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    <link:label id="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Target Allocation, Percentage</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_acc2c84c-5c0b-42da-8a25-a9f96f789047_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Expected contributions in next twelve months</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:type="arc" order="1"/>
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    <link:label id="lab_cenx_NumberOfLaborUnionsUnderNewLaborAgreement_documentation_en-US" xlink:label="lab_cenx_NumberOfLaborUnionsUnderNewLaborAgreement" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The number of labor unions representing a group of employees.</link:label>
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    <link:label id="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_eb6f7e82-6c6f-41b7-845f-55cd692ada3f_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party [Axis]</link:label>
    <link:label id="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_label_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_45d94089-12e4-4287-94f7-a6f22d90fb2f_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Change in fair value of plan assets [Roll Forward]</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward"/>
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    <link:label id="lab_cenx_AluminaMember_9b1915e1-a53c-4c92-a02a-fd20f496e795_terseLabel_en-US" xlink:label="lab_cenx_AluminaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Alumina [Member]</link:label>
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    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_69bbf836-cca8-4ede-a471-77a367e3e5bc_verboseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">LIABILITIES AND SHAREHOLDERS&#8217; EQUITY</link:label>
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    <link:label id="lab_dei_SecurityExchangeName_d68c4373-4e9a-4ffc-95a2-832d9df9519f_terseLabel_en-US" xlink:label="lab_dei_SecurityExchangeName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Security Exchange Name</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_01752408-0da1-41ed-bf12-2ab5430d51d5_periodStartLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair value of plan assets at beginning of year</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_dc18ef9b-e9a2-4b3f-b0fc-f23ccdd75f5c_periodEndLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair value of assets at end of year</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_54664112-f915-44f3-a7f8-fd978adce9dc_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair value of assets</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Amount</link:label>
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    <link:label id="lab_us-gaap_LiabilitiesCurrent_a24c48d1-2851-49ec-97cb-6f2ae808f1f3_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total current liabilities</link:label>
    <link:label id="lab_us-gaap_LiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liabilities, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="lab_us-gaap_LiabilitiesCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_a65ace3c-a7f4-47fe-a8f4-f20b4748352b_terseLabel_en-US" xlink:label="lab_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reclassification out of Accumulated Other Comprehensive Income [Member]</link:label>
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    <link:label id="lab_cenx_DebtDomestic_1064ec3a-4115-4fed-8ec9-6946a8837cdd_terseLabel_en-US" xlink:label="lab_cenx_DebtDomestic" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">U.S. revolving credit facility</link:label>
    <link:label id="lab_cenx_DebtDomestic_label_en-US" xlink:label="lab_cenx_DebtDomestic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt, Domestic</link:label>
    <link:label id="lab_cenx_DebtDomestic_documentation_en-US" xlink:label="lab_cenx_DebtDomestic" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt, Domestic</link:label>
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    <link:label id="lab_cenx_PercentageofWorkForceinUnion_569bc340-dd38-4ab4-a695-112b5e952f5c_terseLabel_en-US" xlink:label="lab_cenx_PercentageofWorkForceinUnion" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage of Company's work force represented by a union</link:label>
    <link:label id="lab_cenx_PercentageofWorkForceinUnion_label_en-US" xlink:label="lab_cenx_PercentageofWorkForceinUnion" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage of Work Force in Union</link:label>
    <link:label id="lab_cenx_PercentageofWorkForceinUnion_documentation_en-US" xlink:label="lab_cenx_PercentageofWorkForceinUnion" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The percentage of a Company's work force that are subject to collective bargaining agreements.</link:label>
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    <link:label id="lab_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_35c9b6a2-e7a1-4c79-b212-51df107ca73d_terseLabel_en-US" xlink:label="lab_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Prepaid and other current assets</link:label>
    <link:label id="lab_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_label_en-US" xlink:label="lab_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Prepaid Expense and Other Assets, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:to="lab_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_VariableRateDomain_2cb63194-391a-4efc-8e36-fec38a1ec2bf_terseLabel_en-US" xlink:label="lab_us-gaap_VariableRateDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Variable Rate [Domain]</link:label>
    <link:label id="lab_us-gaap_VariableRateDomain_label_en-US" xlink:label="lab_us-gaap_VariableRateDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Variable Rate [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VariableRateDomain" xlink:to="lab_us-gaap_VariableRateDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_a6ced05d-5516-4ba7-bcc9-90e2a1e50caf_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2025</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Expected Future Benefit Payment, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_520c3918-3aed-44f9-b96a-ecaffca95ca3_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Valuation allowance</link:label>
    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_label_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:to="lab_us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetsAbstract_3642399a-b588-48ec-a089-84a4dae9dd39_verboseLabel_en-US" xlink:label="lab_us-gaap_AssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">ASSETS</link:label>
    <link:label id="lab_us-gaap_AssetsAbstract_label_en-US" xlink:label="lab_us-gaap_AssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="lab_us-gaap_AssetsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_a53a93e2-1c41-4163-ba74-f3fd6a09431a_terseLabel_en-US" xlink:label="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment, Name [Axis]</link:label>
    <link:label id="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_label_en-US" xlink:label="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment, Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="lab_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_cf0d2afb-4231-405a-b932-cb2d6e16942d_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccountingPoliciesAbstract_3fa3caed-379f-468c-9a37-2439a40f52a7_terseLabel_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:label id="lab_us-gaap_AccountingPoliciesAbstract_label_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingPoliciesAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountingPoliciesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountingPoliciesAbstract" xlink:to="lab_us-gaap_AccountingPoliciesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EntityWideRevenueMajorCustomerLineItems_fdd3d162-22c2-44d6-8a41-3e4da2e1f10d_terseLabel_en-US" xlink:label="lab_us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue, Major Customer [Line Items]</link:label>
    <link:label id="lab_us-gaap_EntityWideRevenueMajorCustomerLineItems_label_en-US" xlink:label="lab_us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue, Major Customer [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EntityWideRevenueMajorCustomerLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:to="lab_us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3_42efe044-c44f-4c90-acee-c73954aed32d_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Transfers out of Level 3</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3" xlink:to="lab_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_CurrentStateAndLocalTaxExpenseBenefit_45186482-77d4-4bca-8071-12f759bd64c6_terseLabel_en-US" xlink:label="lab_us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">State current expense (benefit)</link:label>
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    <link:label id="lab_us-gaap_StatementTable_87268419-fbc8-408f-b657-7311eb9ade94_terseLabel_en-US" xlink:label="lab_us-gaap_StatementTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statement [Table]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RepaymentsOfRelatedPartyDebt" xlink:to="lab_us-gaap_RepaymentsOfRelatedPartyDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_EconomicOwnershipPercentageByRelatedParty_f92256bd-8256-4cc4-a8f5-15a83b8d8f43_terseLabel_en-US" xlink:label="lab_cenx_EconomicOwnershipPercentageByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Glencore economic ownership</link:label>
    <link:label id="lab_cenx_EconomicOwnershipPercentageByRelatedParty_baee4b68-88cf-4c64-bd5e-92d46ed4f979_verboseLabel_en-US" xlink:label="lab_cenx_EconomicOwnershipPercentageByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Economic ownership percentage by related party</link:label>
    <link:label id="lab_cenx_EconomicOwnershipPercentageByRelatedParty_label_en-US" xlink:label="lab_cenx_EconomicOwnershipPercentageByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Economic Ownership Percentage By Related Party</link:label>
    <link:label id="lab_cenx_EconomicOwnershipPercentageByRelatedParty_documentation_en-US" xlink:label="lab_cenx_EconomicOwnershipPercentageByRelatedParty" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The percentage of common stock and preferred stock of the company owned by a related party.</link:label>
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    <link:label id="lab_cenx_MidwestPremiumMWPMember_73a9ebd2-4092-4dc9-9b96-38f1f8597a51_terseLabel_en-US" xlink:label="lab_cenx_MidwestPremiumMWPMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Midwest Premium (MWP) [Member]</link:label>
    <link:label id="lab_cenx_MidwestPremiumMWPMember_label_en-US" xlink:label="lab_cenx_MidwestPremiumMWPMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Midwest Premium (MWP) [Member]</link:label>
    <link:label id="lab_cenx_MidwestPremiumMWPMember_documentation_en-US" xlink:label="lab_cenx_MidwestPremiumMWPMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Midwest Premium (MWP) [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_MidwestPremiumMWPMember" xlink:href="cenx-20201231.xsd#cenx_MidwestPremiumMWPMember"/>
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    <link:label id="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_70e66ef5-981a-4f13-a70f-0739cac260d7_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_1faeb18d-df52-4456-bd5d-6336146747ba_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Expected return on plan assets</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Expected Return (Loss) on Plan Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DerivativeGainLossOnDerivativeNet_034ea43f-06f1-4d1b-b6fd-2ab9440c6397_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeGainLossOnDerivativeNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, gain (loss) on derivative, net</link:label>
    <link:label id="lab_us-gaap_DerivativeGainLossOnDerivativeNet_label_en-US" xlink:label="lab_us-gaap_DerivativeGainLossOnDerivativeNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Gain (Loss) on Derivative, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeGainLossOnDerivativeNet" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeGainLossOnDerivativeNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeGainLossOnDerivativeNet" xlink:to="lab_us-gaap_DerivativeGainLossOnDerivativeNet" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_PerformanceBasedShareAwardsMember_910591e5-25e7-4de6-a825-6d0439b97810_terseLabel_en-US" xlink:label="lab_cenx_PerformanceBasedShareAwardsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Performance-based share awards</link:label>
    <link:label id="lab_cenx_PerformanceBasedShareAwardsMember_label_en-US" xlink:label="lab_cenx_PerformanceBasedShareAwardsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Performance Based Share Awards [Member]</link:label>
    <link:label id="lab_cenx_PerformanceBasedShareAwardsMember_documentation_en-US" xlink:label="lab_cenx_PerformanceBasedShareAwardsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Performance Based Share Awards [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_PerformanceBasedShareAwardsMember" xlink:href="cenx-20201231.xsd#cenx_PerformanceBasedShareAwardsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cenx_PerformanceBasedShareAwardsMember" xlink:to="lab_cenx_PerformanceBasedShareAwardsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentRedemptionPeriodThreeMember_1d4afee0-d20b-46b7-a7a8-b981497534c0_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentRedemptionPeriodThreeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2023 [Member]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentRedemptionPeriodThreeMember_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentRedemptionPeriodThreeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Redemption, Period Three [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodThreeMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodThreeMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodThreeMember" xlink:to="lab_us-gaap_DebtInstrumentRedemptionPeriodThreeMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid_1d0211a9-f8cc-4e19-8107-c257c1264be3_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Capital expenditures</link:label>
    <link:label id="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid_label_en-US" xlink:label="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Capital Expenditures Incurred but Not yet Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:to="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_9554ecd6-98ad-4a45-a5d1-c5d4b6865147_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Issuance for share-based compensation plans (shares)</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_60707878-ed2c-4cd9-a0ab-3189755d8e9c_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]</link:label>
    <link:label id="lab_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_label_en-US" xlink:label="lab_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward" xlink:to="lab_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_PowerSupplyAgreementTerminationNoticePeriod_57bc80b4-5318-47c6-9e17-385549cb6d11_terseLabel_en-US" xlink:label="lab_cenx_PowerSupplyAgreementTerminationNoticePeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Power supply agreement, termination notice period</link:label>
    <link:label id="lab_cenx_PowerSupplyAgreementTerminationNoticePeriod_label_en-US" xlink:label="lab_cenx_PowerSupplyAgreementTerminationNoticePeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Power Supply Agreement, Termination Notice Period</link:label>
    <link:label id="lab_cenx_PowerSupplyAgreementTerminationNoticePeriod_documentation_en-US" xlink:label="lab_cenx_PowerSupplyAgreementTerminationNoticePeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Power Supply Agreement, Termination Notice Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_PowerSupplyAgreementTerminationNoticePeriod" xlink:href="cenx-20201231.xsd#cenx_PowerSupplyAgreementTerminationNoticePeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cenx_PowerSupplyAgreementTerminationNoticePeriod" xlink:to="lab_cenx_PowerSupplyAgreementTerminationNoticePeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract_fb5fba86-54ae-45cb-80ca-35f347e89f58_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred tax assets:</link:label>
    <link:label id="lab_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred Tax Assets, Net of Valuation Allowance [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:to="lab_us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_ValuationAllowanceDeferredTaxAssetReleaseofValuationAllowance_74a13f2b-c38d-446a-af60-c08cf942b5ea_negatedTerseLabel_en-US" xlink:label="lab_cenx_ValuationAllowanceDeferredTaxAssetReleaseofValuationAllowance" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Release of valuation allowance</link:label>
    <link:label id="lab_cenx_ValuationAllowanceDeferredTaxAssetReleaseofValuationAllowance_label_en-US" xlink:label="lab_cenx_ValuationAllowanceDeferredTaxAssetReleaseofValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Valuation Allowance, Deferred Tax Asset, Release of Valuation Allowance</link:label>
    <link:label id="lab_cenx_ValuationAllowanceDeferredTaxAssetReleaseofValuationAllowance_documentation_en-US" xlink:label="lab_cenx_ValuationAllowanceDeferredTaxAssetReleaseofValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Valuation Allowance, Deferred Tax Asset, Release of Valuation Allowance</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_ValuationAllowanceDeferredTaxAssetReleaseofValuationAllowance" xlink:href="cenx-20201231.xsd#cenx_ValuationAllowanceDeferredTaxAssetReleaseofValuationAllowance"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cenx_ValuationAllowanceDeferredTaxAssetReleaseofValuationAllowance" xlink:to="lab_cenx_ValuationAllowanceDeferredTaxAssetReleaseofValuationAllowance" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_d4981dc7-e5a0-48a1-86e3-a038d41a9c21_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment, Type [Axis]</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-Lived Tangible Asset [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
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    <link:label id="lab_srt_NameOfMajorCustomerDomain_b9f71274-13aa-4e9d-be53-e20885bce2fc_terseLabel_en-US" xlink:label="lab_srt_NameOfMajorCustomerDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Major Customer [Domain]</link:label>
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    <link:label id="lab_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_d651af2d-b636-490f-acb4-3e2a65f37ff7_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease, weighted average discount rate, percent</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentFeeAmount_3fbc699b-bf89-4fbb-b844-bac5787f96fe_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentFeeAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Financing fees</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentFeeAmount_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentFeeAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Fee Amount</link:label>
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    <link:label id="lab_dei_EntityIncorporationStateCountryCode_d16fbc1a-15f7-49c4-9af3-332e92ff72a4_terseLabel_en-US" xlink:label="lab_dei_EntityIncorporationStateCountryCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Incorporation, State or Country Code</link:label>
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    <link:label id="lab_us-gaap_DerivativeContractTypeDomain_4f8e5cc2-5a16-40f1-9b96-7175d45355e8_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeContractTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative Contract [Domain]</link:label>
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    <link:label id="lab_cenx_LongTermIncentivePlanMember_e9f11698-f67d-43ef-9a4d-05afc40ef702_terseLabel_en-US" xlink:label="lab_cenx_LongTermIncentivePlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long Term Incentive Plan [Member]</link:label>
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    <link:label id="lab_cenx_LongTermIncentivePlanMember_documentation_en-US" xlink:label="lab_cenx_LongTermIncentivePlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The Long Term Incentive Plan ("LTIP") is designed to align compensation with the interests of our stockholders by linking compensation to share price appreciation and total stockholder return over a multi-year period.</link:label>
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    <link:label id="lab_us-gaap_NumberOfOperatingSegments_0d5c9f88-8053-4ac5-82fb-f742d8248db2_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfOperatingSegments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of operating segments</link:label>
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    <link:label id="lab_us-gaap_DueToAffiliateNoncurrent_f92db08e-9b50-4d89-adb4-65ffde579906_terseLabel_en-US" xlink:label="lab_us-gaap_DueToAffiliateNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Due to affiliates - less current portion</link:label>
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    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_159a308d-2651-49ca-9790-5bff9080d2d0_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net cash provided by financing activities</link:label>
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    <link:label id="lab_cenx_ContingentObligationAccruedInterest_documentation_en-US" xlink:label="lab_cenx_ContingentObligationAccruedInterest" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This amount represents the accrued interest on the E.ON contingent obligation, which is defined as the sum of the carrying values as of the balance sheet date of the E.ON Contingent Obligation which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year or the normal operating cycle, if longer. The E.ON contingent obligation consists of the aggregate E.ON payments. Obligation to make repayments is contingent upon certain operating criteria. When the conditions for repayment are met, and for so long so those conditions continue to be met, there is obligation to make principal and interest payments.</link:label>
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    <link:label id="lab_dei_EntityCurrentReportingStatus_1b8b15c4-fb69-4ac3-8146-cb72279cc004_terseLabel_en-US" xlink:label="lab_dei_EntityCurrentReportingStatus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Current Reporting Status</link:label>
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    <link:label id="lab_us-gaap_EarningsPerSharePolicyTextBlock_e35b1fc9-7016-4bb0-9d91-0f9aae382560_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings per share</link:label>
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    <link:label id="lab_us-gaap_StockholdersEquity_29599adb-c73d-4108-a0eb-8357d7a3d520_totalLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total shareholders&#8217; equity</link:label>
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    <link:label id="lab_us-gaap_StockholdersEquity_52075616-2dda-496a-adda-c2fa235e5282_periodEndLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Balance, end</link:label>
    <link:label id="lab_us-gaap_StockholdersEquity_label_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders' Equity Attributable to Parent</link:label>
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    <link:label id="lab_us-gaap_ValuationTechniqueDiscountedCashFlowMember_202558de-1272-46c8-ae49-45057e4254aa_terseLabel_en-US" xlink:label="lab_us-gaap_ValuationTechniqueDiscountedCashFlowMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Discounted Cash Flow [Member]</link:label>
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    <link:label id="lab_dei_EntityAddressCityOrTown_1a365d18-43c4-420e-8e9e-cacf181173c1_terseLabel_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, City or Town</link:label>
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    <link:label id="lab_cenx_ScheduleOfCommonandPreferredStockRollForwardTableTextBlock_a0a7ac5a-3109-4c6a-b75c-62dde7a83f8c_terseLabel_en-US" xlink:label="lab_cenx_ScheduleOfCommonandPreferredStockRollForwardTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of common and preferred stock activity</link:label>
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    <link:label id="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis_871cba28-584c-415b-9b9a-3b4360b491cd_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Hierarchy and NAV [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis_label_en-US" xlink:label="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Hierarchy and NAV [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
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    <link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_83b3bf5e-9955-4161-a33a-70070a2b6137_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Service-Based Share Awards [Member]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:to="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear_94203b73-0eee-490b-83ca-74bd5f0d38fd_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Medical cost inflation rate</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear"/>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_a08e7cc7-cbd3-4b16-9044-54df42fd6e44_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2025</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive"/>
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    <link:label id="lab_cenx_TrustAssetsFairValueDisclosure_fc772cce-542f-468e-a647-8e9738e8d6bf_verboseLabel_en-US" xlink:label="lab_cenx_TrustAssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Trust assets</link:label>
    <link:label id="lab_cenx_TrustAssetsFairValueDisclosure_label_en-US" xlink:label="lab_cenx_TrustAssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Trust Assets, Fair Value Disclosure</link:label>
    <link:label id="lab_cenx_TrustAssetsFairValueDisclosure_documentation_en-US" xlink:label="lab_cenx_TrustAssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair value as of the balance sheet date of all trust assets as of the balance sheet date.</link:label>
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    <link:label id="lab_cenx_AdditionalfinancialinformationdisclosuresAbstract_0d25baa0-c94d-46ef-9405-d767a303db51_terseLabel_en-US" xlink:label="lab_cenx_AdditionalfinancialinformationdisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Additional financial information disclosures [Abstract]</link:label>
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    <link:label id="lab_cenx_AdditionalfinancialinformationdisclosuresAbstract_documentation_en-US" xlink:label="lab_cenx_AdditionalfinancialinformationdisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Additional financial information disclosures</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_AdditionalfinancialinformationdisclosuresAbstract" xlink:href="cenx-20201231.xsd#cenx_AdditionalfinancialinformationdisclosuresAbstract"/>
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    <link:label id="lab_cenx_GrundartangiHSLandsvirkjunandORMember_d8dd4ad8-b4db-45f0-a550-2b0eff9a853f_terseLabel_en-US" xlink:label="lab_cenx_GrundartangiHSLandsvirkjunandORMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Grundartangi - HS, Landsvirkjun and OR [Member]</link:label>
    <link:label id="lab_cenx_GrundartangiHSLandsvirkjunandORMember_label_en-US" xlink:label="lab_cenx_GrundartangiHSLandsvirkjunandORMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Grundartangi - HS, Landsvirkjun and OR [Member]</link:label>
    <link:label id="lab_cenx_GrundartangiHSLandsvirkjunandORMember_documentation_en-US" xlink:label="lab_cenx_GrundartangiHSLandsvirkjunandORMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Grundartangi - HS, Landsvirkjun and OR [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_GrundartangiHSLandsvirkjunandORMember" xlink:href="cenx-20201231.xsd#cenx_GrundartangiHSLandsvirkjunandORMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cenx_GrundartangiHSLandsvirkjunandORMember" xlink:to="lab_cenx_GrundartangiHSLandsvirkjunandORMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShortTermLeaseCost_81a29a4f-0e7f-4aa3-aa6c-79f87a0dbb65_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermLeaseCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short term lease expense</link:label>
    <link:label id="lab_us-gaap_ShortTermLeaseCost_label_en-US" xlink:label="lab_us-gaap_ShortTermLeaseCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term Lease, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermLeaseCost" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermLeaseCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShortTermLeaseCost" xlink:to="lab_us-gaap_ShortTermLeaseCost" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncreaseMax_909c0060-56b8-4e93-addd-88e7ae181d9e_terseLabel_en-US" xlink:label="lab_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncreaseMax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Rate of compensation increase, group 2</link:label>
    <link:label id="lab_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncreaseMax_label_en-US" xlink:label="lab_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncreaseMax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase, Max</link:label>
    <link:label id="lab_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncreaseMax_documentation_en-US" xlink:label="lab_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncreaseMax" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The maximum expected rate of compensation increases (for pay-related plans).</link:label>
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    <link:label id="lab_cenx_DeferredTaxAssetsForeignBasisDifferences_2bb0330b-c02c-4dac-93f0-399b5bd4acc6_terseLabel_en-US" xlink:label="lab_cenx_DeferredTaxAssetsForeignBasisDifferences" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Foreign basis differences</link:label>
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    <link:label id="lab_cenx_ServiceBasedShareAwardsMember_ae3e6957-919c-4226-914c-080a5e098663_terseLabel_en-US" xlink:label="lab_cenx_ServiceBasedShareAwardsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Service-Based Share Awards [Member]</link:label>
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    <link:label id="lab_us-gaap_StatementClassOfStockAxis_7a211fa2-0c9e-4453-aea1-c7da5227d3fc_terseLabel_en-US" xlink:label="lab_us-gaap_StatementClassOfStockAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Class of Stock [Axis]</link:label>
    <link:label id="lab_us-gaap_StatementClassOfStockAxis_label_en-US" xlink:label="lab_us-gaap_StatementClassOfStockAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Class of Stock [Axis]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementClassOfStockAxis" xlink:to="lab_us-gaap_StatementClassOfStockAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfDerivativeInstrumentsTextBlock_74af6570-f0da-4960-9f02-69be0743c5a9_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDerivativeInstrumentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of net gain (loss) on forward and derivative contracts</link:label>
    <link:label id="lab_us-gaap_ScheduleOfDerivativeInstrumentsTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDerivativeInstrumentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Derivative Instruments [Table Text Block]</link:label>
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    <link:label id="lab_cenx_SegmentReportingCorporateUnallocatedAssets_aeda3aa6-5826-47b5-8df1-1edaa89ea70a_terseLabel_en-US" xlink:label="lab_cenx_SegmentReportingCorporateUnallocatedAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Corporate, unallocated</link:label>
    <link:label id="lab_cenx_SegmentReportingCorporateUnallocatedAssets_label_en-US" xlink:label="lab_cenx_SegmentReportingCorporateUnallocatedAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Segment Reporting Corporate Unallocated Assets</link:label>
    <link:label id="lab_cenx_SegmentReportingCorporateUnallocatedAssets_documentation_en-US" xlink:label="lab_cenx_SegmentReportingCorporateUnallocatedAssets" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The remaining assets are unallocated corporate assets. Not including: Segment assets include cash and cash equivalents, accounts receivable, due from affiliates, prepaid and other current assets, inventory, intangible assets and property, plant and equipment-net.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_SegmentReportingCorporateUnallocatedAssets" xlink:href="cenx-20201231.xsd#cenx_SegmentReportingCorporateUnallocatedAssets"/>
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    <link:label id="lab_us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount_c7a6cb84-075b-4cff-831e-aae25c2ad102_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Company matching contribution to defined contribution (401(k)) plans</link:label>
    <link:label id="lab_us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount_label_en-US" xlink:label="lab_us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Contribution Plan, Employer Discretionary Contribution Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" xlink:to="lab_us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_DebtOfferToPurchasePercentageOfOutstandingAmount_b66d08f5-1cf8-414f-a65d-fe59dcac3080_terseLabel_en-US" xlink:label="lab_cenx_DebtOfferToPurchasePercentageOfOutstandingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage of outstanding amount, offer to purchase</link:label>
    <link:label id="lab_cenx_DebtOfferToPurchasePercentageOfOutstandingAmount_label_en-US" xlink:label="lab_cenx_DebtOfferToPurchasePercentageOfOutstandingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Offer To Purchase Percentage Of Outstanding Amount</link:label>
    <link:label id="lab_cenx_DebtOfferToPurchasePercentageOfOutstandingAmount_documentation_en-US" xlink:label="lab_cenx_DebtOfferToPurchasePercentageOfOutstandingAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Offer To Purchase Percentage Of Outstanding Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_DebtOfferToPurchasePercentageOfOutstandingAmount" xlink:href="cenx-20201231.xsd#cenx_DebtOfferToPurchasePercentageOfOutstandingAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cenx_DebtOfferToPurchasePercentageOfOutstandingAmount" xlink:to="lab_cenx_DebtOfferToPurchasePercentageOfOutstandingAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_IndustrialRevenueBondsCurrent_1a073834-ac12-4df0-83b7-6a02dc2bdabd_terseLabel_en-US" xlink:label="lab_cenx_IndustrialRevenueBondsCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Industrial revenue bonds</link:label>
    <link:label id="lab_cenx_IndustrialRevenueBondsCurrent_0cd1754e-20fe-46b0-b1e1-2c12a1a82221_verboseLabel_en-US" xlink:label="lab_cenx_IndustrialRevenueBondsCurrent" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Hancock County industrial revenue bonds (IRBs) due April 2028, interest payable quarterly (variable interest rates (not to exceed 12%))</link:label>
    <link:label id="lab_cenx_IndustrialRevenueBondsCurrent_label_en-US" xlink:label="lab_cenx_IndustrialRevenueBondsCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Industrial Revenue Bonds, Current</link:label>
    <link:label id="lab_cenx_IndustrialRevenueBondsCurrent_documentation_en-US" xlink:label="lab_cenx_IndustrialRevenueBondsCurrent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Carrying value as of the balance sheet date of the long-term debt associated with industrial revenue bonds. For classified balance sheets, these bonds are considered current assets because they are remarketed weekly and the bonds could be required to be repaid upon demand if there is a failed remarketing.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_IndustrialRevenueBondsCurrent" xlink:href="cenx-20201231.xsd#cenx_IndustrialRevenueBondsCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cenx_IndustrialRevenueBondsCurrent" xlink:to="lab_cenx_IndustrialRevenueBondsCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_CondensedStatementOfIncomeCaptionsLineItems_4df3157b-280a-44e9-86f0-b7d055971492_terseLabel_en-US" xlink:label="lab_srt_CondensedStatementOfIncomeCaptionsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Condensed Statement of Income Captions [Line Items]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedStatementOfIncomeCaptionsLineItems" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedStatementOfIncomeCaptionsLineItems"/>
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    <link:label id="lab_us-gaap_QuarterlyFinancialDataAbstract_3e992b92-7df9-43b4-a143-3f51f7891fa3_terseLabel_en-US" xlink:label="lab_us-gaap_QuarterlyFinancialDataAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Quarterly Financial Data [Abstract]</link:label>
    <link:label id="lab_us-gaap_QuarterlyFinancialDataAbstract_label_en-US" xlink:label="lab_us-gaap_QuarterlyFinancialDataAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Quarterly Financial Data [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_QuarterlyFinancialDataAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_QuarterlyFinancialDataAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_QuarterlyFinancialDataAbstract" xlink:to="lab_us-gaap_QuarterlyFinancialDataAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LiabilitiesFairValueDisclosure_3338c249-99fa-4769-a957-dd2d9678ef12_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">TOTAL</link:label>
    <link:label id="lab_us-gaap_LiabilitiesFairValueDisclosure_label_en-US" xlink:label="lab_us-gaap_LiabilitiesFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Financial and Nonfinancial Liabilities, Fair Value Disclosure</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosure" xlink:to="lab_us-gaap_LiabilitiesFairValueDisclosure" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrent_97bb68e4-36ac-4cc7-8751-ae93c043ed27_terseLabel_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued and other current liabilities</link:label>
    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued Liabilities, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:to="lab_us-gaap_AccruedLiabilitiesCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareDiluted_1c680dc2-e421-41ff-81c1-dc66ec4065c9_verboseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Diluted earnings (loss) per share (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareDiluted_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share, Diluted</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareDiluted"/>
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    <link:label id="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock_1317e6a6-3d24-49a0-b67d-5111b5cd6966_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of revenue from external customers and long-lived assets, by geographical areas</link:label>
    <link:label id="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]</link:label>
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    <link:label id="lab_cenx_PaymentOfDebtRetirementCostsNet_aa5cf1a3-7c9a-49f0-bb07-cdc801c76dc5_negatedTerseLabel_en-US" xlink:label="lab_cenx_PaymentOfDebtRetirementCostsNet" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt retirement costs</link:label>
    <link:label id="lab_cenx_PaymentOfDebtRetirementCostsNet_label_en-US" xlink:label="lab_cenx_PaymentOfDebtRetirementCostsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Payment of Debt Retirement Costs, Net</link:label>
    <link:label id="lab_cenx_PaymentOfDebtRetirementCostsNet_documentation_en-US" xlink:label="lab_cenx_PaymentOfDebtRetirementCostsNet" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Payment of Debt Retirement Costs, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_PaymentOfDebtRetirementCostsNet" xlink:href="cenx-20201231.xsd#cenx_PaymentOfDebtRetirementCostsNet"/>
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    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesNetAbstract_a3011fbf-8770-490b-84d7-295d250558b1_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred tax liabilities:</link:label>
    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesNetAbstract_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred Tax Liabilities, Net [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNetAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:to="lab_us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfStockByClassTable_751f4a34-1c52-4b49-b22e-5e577c4afa2e_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfStockByClassTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Stock by Class [Table]</link:label>
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    <link:label id="lab_dei_EntityAddressAddressLine1_168a05fa-9d59-493b-af22-cc722b785c91_terseLabel_en-US" xlink:label="lab_dei_EntityAddressAddressLine1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, Address Line One</link:label>
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    <link:label id="lab_cenx_SebreeMember_documentation_en-US" xlink:label="lab_cenx_SebreeMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Sebree [Member]</link:label>
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    <link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_1b44ab48-3eb2-4406-885a-9c3e5865fead_totalLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total deferred expense (benefit)</link:label>
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    <link:label id="lab_us-gaap_DerivativeFairValueOfDerivativeLiability_67ccc1be-933b-4402-8ce2-fbb80c0677f1_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liability Fair Value</link:label>
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    <link:label id="lab_cenx_LitigationSettlementInstallmentPeriod_0cbd3c24-c1e4-4a5d-b492-a09581d84a93_terseLabel_en-US" xlink:label="lab_cenx_LitigationSettlementInstallmentPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Litigation settlement installment period</link:label>
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    <link:label id="lab_cenx_ContingentObligationMember_927d8ca6-2a50-4b47-9e6a-60e0b0bc32c6_terseLabel_en-US" xlink:label="lab_cenx_ContingentObligationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contingent obligation [Member]</link:label>
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    <link:label id="lab_srt_MaximumMember_3f9a66f3-cb93-4a95-a9de-5dc8419ec329_terseLabel_en-US" xlink:label="lab_srt_MaximumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maximum [Member]</link:label>
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    <link:label id="lab_us-gaap_PreferredStockSharesAuthorized_520757c9-ec2c-4240-bcb8-40b8d3accaa7_verboseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred stock, shares authorized (shares)</link:label>
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    <link:label id="lab_cenx_BhhMember_documentation_en-US" xlink:label="lab_cenx_BhhMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">A related party.</link:label>
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    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign_f0917408-d65c-4aa8-8aea-63b8dea67041_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Foreign&#160;</link:label>
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    <link:label id="lab_dei_EntityShellCompany_dbda072e-0b64-4635-ae69-6d1e28a07cd4_terseLabel_en-US" xlink:label="lab_dei_EntityShellCompany" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Shell Company</link:label>
    <link:label id="lab_dei_EntityShellCompany_label_en-US" xlink:label="lab_dei_EntityShellCompany" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Shell Company</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentRedemptionTable_abc0fc8b-48f4-4f41-be35-0b01f2a16cd5_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentRedemptionTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument Redemption [Table]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentRedemptionTable_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentRedemptionTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument Redemption [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentRedemptionTable" xlink:to="lab_us-gaap_DebtInstrumentRedemptionTable" xlink:type="arc" order="1"/>
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    <link:label id="lab_dei_DocumentType_1340321e-3e37-4b77-a966-2ac9b6d4c694_terseLabel_en-US" xlink:label="lab_dei_DocumentType" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Type</link:label>
    <link:label id="lab_dei_DocumentType_label_en-US" xlink:label="lab_dei_DocumentType" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Type</link:label>
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    <link:label id="lab_dei_IcfrAuditorAttestationFlag_1356ad45-22f9-4e05-ad91-11034357de0d_terseLabel_en-US" xlink:label="lab_dei_IcfrAuditorAttestationFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">ICFR Auditor Attestation Flag</link:label>
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    <link:label id="lab_us-gaap_OtherNonoperatingIncomeExpense_15880ad7-6d36-4dc5-a76b-23806760237d_verboseLabel_en-US" xlink:label="lab_us-gaap_OtherNonoperatingIncomeExpense" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other income (expense) - net</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpense" xlink:to="lab_us-gaap_OtherNonoperatingIncomeExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TreasuryStockMember_ce561370-8b15-4f2c-acd8-c2e0d267756a_terseLabel_en-US" xlink:label="lab_us-gaap_TreasuryStockMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Treasury stock, at cost</link:label>
    <link:label id="lab_us-gaap_TreasuryStockMember_44a2fc0d-b727-4d8a-8870-6269c1db96b5_verboseLabel_en-US" xlink:label="lab_us-gaap_TreasuryStockMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Treasury</link:label>
    <link:label id="lab_us-gaap_TreasuryStockMember_label_en-US" xlink:label="lab_us-gaap_TreasuryStockMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Treasury Stock [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TreasuryStockMember" xlink:to="lab_us-gaap_TreasuryStockMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock_733c4a80-5fd0-4e6b-800d-4322ade6a705_terseLabel_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Pension and Other Postretirement Benefits</link:label>
    <link:label id="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Retirement Benefits [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:to="lab_us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_8ae92581-ed09-49e3-9515-3ba9c86657e9_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Components of Accumulated Other Comprehensive Loss</link:label>
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    <link:label id="lab_us-gaap_FairValueInputsLevel3Member_96b046e7-8324-44e0-bb65-49a7a4c73c7d_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel3Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Level 3</link:label>
    <link:label id="lab_us-gaap_FairValueInputsLevel3Member_label_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel3Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value, Inputs, Level 3 [Member]</link:label>
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    <link:label id="lab_us-gaap_InventoryWriteDown_f8e194b3-0d4a-425b-82a6-f3ddd85e8e12_terseLabel_en-US" xlink:label="lab_us-gaap_InventoryWriteDown" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lower of cost or NRV inventory adjustment</link:label>
    <link:label id="lab_us-gaap_InventoryWriteDown_label_en-US" xlink:label="lab_us-gaap_InventoryWriteDown" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inventory Write-down</link:label>
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    <link:label id="lab_us-gaap_SecuredDebt_7194fe4c-3e5d-4fb8-a798-49737f61e2a8_terseLabel_en-US" xlink:label="lab_us-gaap_SecuredDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revolving credit facility</link:label>
    <link:label id="lab_us-gaap_SecuredDebt_label_en-US" xlink:label="lab_us-gaap_SecuredDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Secured Debt</link:label>
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    <link:label id="lab_us-gaap_RetainedEarningsAccumulatedDeficit_97d0a5da-41ba-4c18-99e9-3a705ed09a2d_verboseLabel_en-US" xlink:label="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accumulated deficit</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
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    <link:label id="lab_us-gaap_RepaymentsOfLinesOfCredit_74253b09-6660-4977-93c2-7d731342c894_negatedLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfLinesOfCredit" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Repayments under revolving credit facilities</link:label>
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    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_a91fe08a-f44c-4a83-9f35-374a3e034a33_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Tax over financial statement depreciation</link:label>
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    <link:label id="lab_us-gaap_PaymentsForLegalSettlements_631af7ae-9aca-4afc-a095-f421f08669a7_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsForLegalSettlements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Ravenswood retiree legal settlement</link:label>
    <link:label id="lab_us-gaap_PaymentsForLegalSettlements_label_en-US" xlink:label="lab_us-gaap_PaymentsForLegalSettlements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Payments for Legal Settlements</link:label>
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    <link:label id="lab_cenx_PercentageOfDomesticWorkForceInUnion_da09bd02-c6d7-46e4-813f-647dadc14d6b_verboseLabel_en-US" xlink:label="lab_cenx_PercentageOfDomesticWorkForceInUnion" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage of U.S. based work force represented by a union</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfChangeInAssetRetirementObligationTableTextBlock_43fdccde-6244-4683-9fbc-849f696429b9_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfChangeInAssetRetirementObligationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of changes in asset retirement obligations</link:label>
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    <link:label id="lab_us-gaap_DerivativeLiabilities_9c76ab02-dfe5-4134-9dca-ca0258556292_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative instruments</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeLiabilities" xlink:to="lab_us-gaap_DerivativeLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_c3398792-8c5a-41b9-896f-d2f17ea3a2ee_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:</link:label>
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    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerAbstract_8abbad75-63b8-4abb-80d0-ca09b679d325_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue from Contract with Customer [Abstract]</link:label>
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    <link:label id="lab_cenx_ContingentObligation_5e223831-153d-4dc4-8108-c45e64ed07e5_negatedTotalLabel_en-US" xlink:label="lab_cenx_ContingentObligation" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contingent obligation</link:label>
    <link:label id="lab_cenx_ContingentObligation_label_en-US" xlink:label="lab_cenx_ContingentObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contingent Obligation</link:label>
    <link:label id="lab_cenx_ContingentObligation_documentation_en-US" xlink:label="lab_cenx_ContingentObligation" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Sum of the carrying values as of the balance sheet date of the E.ON Contingent Obligation which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year or the normal operating cycle, if longer. The E.ON contingent obligation consists of the aggregate E.ON payments. Obligation to make repayments is contingent upon certain operating criteria. When the conditions for repayment are met, and for so long so those conditions continue to be met, there is obligation to make principal and interest payments.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_ContingentObligation" xlink:href="cenx-20201231.xsd#cenx_ContingentObligation"/>
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    <link:label id="lab_us-gaap_OtherOperatingIncome_5db91faf-76e2-4e68-a7e1-b4653235d25d_terseLabel_en-US" xlink:label="lab_us-gaap_OtherOperatingIncome" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other customers</link:label>
    <link:label id="lab_us-gaap_OtherOperatingIncome_label_en-US" xlink:label="lab_us-gaap_OtherOperatingIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Operating Income</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherOperatingIncome" xlink:to="lab_us-gaap_OtherOperatingIncome" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationTotalRealizedUnrealizedGainsLossesAbstract_80cea20e-ad66-4ea8-8910-d0187117e001_terseLabel_en-US" xlink:label="lab_cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationTotalRealizedUnrealizedGainsLossesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total realized/unrealized gains (losses)</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationTotalRealizedUnrealizedGainsLossesAbstract" xlink:href="cenx-20201231.xsd#cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationTotalRealizedUnrealizedGainsLossesAbstract"/>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation_087551eb-a2e5-4604-9da0-6cb6ee9c1577_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Projected benefit obligation for plans with accumulated benefit obligations in excess of plan assets</link:label>
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    <link:label id="lab_cenx_PerformancebasedShareExpense_d36edfe7-d66f-411a-9e8a-67d0ad78aa60_terseLabel_en-US" xlink:label="lab_cenx_PerformancebasedShareExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Performance-based share expense</link:label>
    <link:label id="lab_cenx_PerformancebasedShareExpense_label_en-US" xlink:label="lab_cenx_PerformancebasedShareExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Performance-based Share Expense</link:label>
    <link:label id="lab_cenx_PerformancebasedShareExpense_documentation_en-US" xlink:label="lab_cenx_PerformancebasedShareExpense" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The amount of expense, gross of income tax, recognized during the period arising from performance-based share arrangements.</link:label>
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    <link:label id="lab_us-gaap_LettersOfCreditOutstandingAmount_3975a477-eaa4-43ba-8926-ab6de345d201_terseLabel_en-US" xlink:label="lab_us-gaap_LettersOfCreditOutstandingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Outstanding letters of credit issued</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LettersOfCreditOutstandingAmount" xlink:to="lab_us-gaap_LettersOfCreditOutstandingAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskByTypeAxis_426bfabc-3d31-46cb-8be5-90ef2f8449cc_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Concentration Risk Type [Axis]</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskByTypeAxis_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Concentration Risk Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis" xlink:to="lab_us-gaap_ConcentrationRiskByTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_AccumulatedOtherComprehensiveIncomeTaxEffect_45db99f3-9978-438a-9637-77ed08706848_negatedTerseLabel_en-US" xlink:label="lab_cenx_AccumulatedOtherComprehensiveIncomeTaxEffect" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income tax effect</link:label>
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    <link:label id="lab_cenx_AccumulatedOtherComprehensiveIncomeTaxEffect_documentation_en-US" xlink:label="lab_cenx_AccumulatedOtherComprehensiveIncomeTaxEffect" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The tax effect of AOCI as reported on the balance sheet.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_AccumulatedOtherComprehensiveIncomeTaxEffect" xlink:href="cenx-20201231.xsd#cenx_AccumulatedOtherComprehensiveIncomeTaxEffect"/>
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    <link:label id="lab_cenx_ValuationAllowanceDeferredTaxAssetRemeasurementDueToTaxCutsJobsAct_99b22ca7-3bd4-42a8-94f9-0d86a67eb9d6_terseLabel_en-US" xlink:label="lab_cenx_ValuationAllowanceDeferredTaxAssetRemeasurementDueToTaxCutsJobsAct" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remeasurement of deferred tax assets</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_cenx_ValuationAllowanceDeferredTaxAssetRemeasurementDueToTaxCutsJobsAct" xlink:href="cenx-20201231.xsd#cenx_ValuationAllowanceDeferredTaxAssetRemeasurementDueToTaxCutsJobsAct"/>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanInformationAboutPlanAssetsAbstract_088b57ed-3226-4308-8b9f-c38818c3e001_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanInformationAboutPlanAssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Information about Plan Assets [Abstract]</link:label>
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    <link:label id="lab_srt_CondensedBalanceSheetStatementsCaptionsLineItems_b5be416a-0970-4343-9bfb-7720c1e972e5_terseLabel_en-US" xlink:label="lab_srt_CondensedBalanceSheetStatementsCaptionsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Condensed Balance Sheet Statements, Captions [Line Items]</link:label>
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    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies_387cb642-83fb-4c86-8877-7b2405489d1e_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Changes in uncertain tax reserves</link:label>
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    <link:label id="lab_cenx_Mt.HollyMember_9d9a2dc7-44df-45c4-94c6-8113f2a9653c_terseLabel_en-US" xlink:label="lab_cenx_Mt.HollyMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Mt. Holly [Member]</link:label>
    <link:label id="lab_cenx_Mt.HollyMember_label_en-US" xlink:label="lab_cenx_Mt.HollyMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Mt. Holly [Member]</link:label>
    <link:label id="lab_cenx_Mt.HollyMember_documentation_en-US" xlink:label="lab_cenx_Mt.HollyMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Mt. Holly [Member]</link:label>
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    <link:label id="lab_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_a3d74cf7-1390-4d16-a251-a465f21a9efb_terseLabel_en-US" xlink:label="lab_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining authorized repurchase amount</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember_f07af902-825f-4985-a486-239438a49c12_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">International equities</link:label>
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    <link:label id="lab_us-gaap_PreferredStockParOrStatedValuePerShare_e38aac86-f1a2-4051-8368-783aabc4a9f8_verboseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred stock, par value (in dollars per share)</link:label>
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    <link:label id="lab_dei_DocumentsIncorporatedByReferenceTextBlock_8358eba6-00ca-4944-ab65-57a2af7a6198_terseLabel_en-US" xlink:label="lab_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Documents Incorporated by Reference</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock_ebdde407-7c0b-41cc-862b-1ad9fd0969f9_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reconciliation of the statutory U.S. Federal income tax rate to the effective income tax rate on income (loss)</link:label>
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    <link:label id="lab_cenx_OtherMember_4147e981-4886-48b7-9dfb-6e6aba773808_terseLabel_en-US" xlink:label="lab_cenx_OtherMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other [Member]</link:label>
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    <link:label id="lab_cenx_OtherMember_documentation_en-US" xlink:label="lab_cenx_OtherMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The other geographic segment representing facts about a reporting entity disaggregated by the geographic area of the entities activities.</link:label>
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    <link:label id="lab_dei_LegalEntityAxis_788a7854-81b3-4261-bba8-d4f61582cfb5_terseLabel_en-US" xlink:label="lab_dei_LegalEntityAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Legal Entity [Axis]</link:label>
    <link:label id="lab_dei_LegalEntityAxis_label_en-US" xlink:label="lab_dei_LegalEntityAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Legal Entity [Axis]</link:label>
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    <link:label id="lab_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_950059af-8ad5-4cd3-9c9f-aa449689c3c1_terseLabel_en-US" xlink:label="lab_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other comprehensive (loss) before reclassifications</link:label>
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    <link:label id="lab_dei_CityAreaCode_dcd88b22-24c5-431b-af96-463abb2fe1fb_terseLabel_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">City Area Code</link:label>
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    <link:label id="lab_srt_NonGuarantorSubsidiariesMember_d37457c3-2894-44a3-ba5c-4b42d2411522_terseLabel_en-US" xlink:label="lab_srt_NonGuarantorSubsidiariesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Combined Non-Guarantor Subsidiaries [Member]</link:label>
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    <link:label id="lab_us-gaap_IncomeTaxAuthorityAxis_fe136a5d-cb5a-42cf-a8c8-32be8b3681dc_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxAuthorityAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Tax Authority [Axis]</link:label>
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    <link:label id="lab_dei_DocumentPeriodEndDate_5fcfcfe7-bdd5-4349-b574-e227da91e70f_terseLabel_en-US" xlink:label="lab_dei_DocumentPeriodEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Period End Date</link:label>
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    <link:label id="lab_us-gaap_StockRepurchaseProgramAuthorizedAmount1_b36b56b9-cb58-46e9-b28b-fafa02b8d2f4_terseLabel_en-US" xlink:label="lab_us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Authorized repurchase amount</link:label>
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    <link:label id="lab_cenx_ContingentObligationPrincipal_2e3d5c17-4fb2-49e0-9836-41cc32d25c36_negatedTerseLabel_en-US" xlink:label="lab_cenx_ContingentObligationPrincipal" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contingent obligation &#8211; principal</link:label>
    <link:label id="lab_cenx_ContingentObligationPrincipal_label_en-US" xlink:label="lab_cenx_ContingentObligationPrincipal" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contingent Obligation, Principal</link:label>
    <link:label id="lab_cenx_ContingentObligationPrincipal_documentation_en-US" xlink:label="lab_cenx_ContingentObligationPrincipal" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This amount represents the principal amount of the E.ON contingent obligation, which is defined as the sum of the carrying values as of the balance sheet date of the E.ON Contingent Obligation which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year or the normal operating cycle, if longer. The E.ON contingent obligation consists of the aggregate E.ON payments. Obligation to make repayments is contingent upon certain operating criteria. When the conditions for repayment are met, and for so long so those conditions continue to be met, there is obligation to make principal and interest payments.</link:label>
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    <link:label id="lab_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_2d766457-b97f-4223-a3eb-6b2f7aec9475_terseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnDerivativeInstrumentsNetPretax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net gain (loss) on forward and derivative contracts</link:label>
    <link:label id="lab_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_label_en-US" xlink:label="lab_us-gaap_GainLossOnDerivativeInstrumentsNetPretax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gain (Loss) on Derivative Instruments, Net, Pretax</link:label>
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    <link:label id="lab_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_64d83918-a7e7-4554-8920-8564936bad3e_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">ROUL - current [extensible list]</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList"/>
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    <link:label id="lab_us-gaap_DisaggregationOfRevenueTableTextBlock_90ba6c67-9153-4428-9ba6-0b9a64b0ab60_terseLabel_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disaggregation of revenue</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:to="lab_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetRetirementObligationLiabilitiesIncurred_666b0276-0d81-44a2-aa3c-584d6a292a67_terseLabel_en-US" xlink:label="lab_us-gaap_AssetRetirementObligationLiabilitiesIncurred" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Additional ARO liability incurred</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetRetirementObligationLiabilitiesIncurred" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetRetirementObligationLiabilitiesIncurred"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetRetirementObligationLiabilitiesIncurred" xlink:to="lab_us-gaap_AssetRetirementObligationLiabilitiesIncurred" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount_d1f59dea-e943-4619-9cba-13ec2c15c2a4_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based payment arrangement, amount capitalized</link:label>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount_label_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Amount Capitalized</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount" xlink:to="lab_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock_ba717f3c-5baf-4a85-8dbf-d91913b717e0_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Summary of share-based compensation expense</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongtermDebtTypeDomain_26055fab-bc9d-4168-8b96-40bca42afc9e_terseLabel_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Type [Domain]</link:label>
    <link:label id="lab_us-gaap_LongtermDebtTypeDomain_label_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongtermDebtTypeDomain" xlink:to="lab_us-gaap_LongtermDebtTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_CoverAbstract_bef8459c-9314-4a5e-86db-fa53e52b0e26_terseLabel_en-US" xlink:label="lab_dei_CoverAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cover [Abstract]</link:label>
    <link:label id="lab_dei_CoverAbstract_label_en-US" xlink:label="lab_dei_CoverAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cover [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CoverAbstract" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_CoverAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CoverAbstract" xlink:to="lab_dei_CoverAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost_30af2fa2-f5e0-4129-a48e-08f5eb04dad4_terseLabel_en-US" xlink:label="lab_us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contributions of Century Aluminum Company</link:label>
    <link:label id="lab_us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost_label_en-US" xlink:label="lab_us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Multiemployer Plan, Pension, Significant, Employer Contribution, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost" xlink:to="lab_us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_DebtInstrumentInterestRateStatedPercentageAdditionalNotesOrCash_30809add-3f1b-4734-bc05-d24580e85ba4_terseLabel_en-US" xlink:label="lab_cenx_DebtInstrumentInterestRateStatedPercentageAdditionalNotesOrCash" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest rate, additional notes or cash percentage</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_cenx_DebtInstrumentInterestRateStatedPercentageAdditionalNotesOrCash" xlink:href="cenx-20201231.xsd#cenx_DebtInstrumentInterestRateStatedPercentageAdditionalNotesOrCash"/>
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    <link:label id="lab_us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock_25e9c1a7-8120-4602-8317-21dadd632922_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Components of pre-tax book income (loss)</link:label>
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    <link:label id="lab_cenx_AccruedLiabilitiesCurrentandOther_a16a5b34-29e5-4117-95a5-1fde129cef3c_terseLabel_en-US" xlink:label="lab_cenx_AccruedLiabilitiesCurrentandOther" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued and other current liabilities</link:label>
    <link:label id="lab_cenx_AccruedLiabilitiesCurrentandOther_label_en-US" xlink:label="lab_cenx_AccruedLiabilitiesCurrentandOther" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued Liabilities, Current and Other</link:label>
    <link:label id="lab_cenx_AccruedLiabilitiesCurrentandOther_documentation_en-US" xlink:label="lab_cenx_AccruedLiabilitiesCurrentandOther" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued Liabilities, Current and Other</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_AccruedLiabilitiesCurrentandOther" xlink:href="cenx-20201231.xsd#cenx_AccruedLiabilitiesCurrentandOther"/>
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    <link:label id="lab_us-gaap_FixedIncomeSecuritiesMember_63f3b1c4-5556-46db-b681-94dea592446d_terseLabel_en-US" xlink:label="lab_us-gaap_FixedIncomeSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fixed income</link:label>
    <link:label id="lab_us-gaap_FixedIncomeSecuritiesMember_label_en-US" xlink:label="lab_us-gaap_FixedIncomeSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fixed Income Securities [Member]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FixedIncomeSecuritiesMember" xlink:to="lab_us-gaap_FixedIncomeSecuritiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_ContingentObligationDerivativeAsset_01284ec6-4d18-4570-94cd-93131ac6ab3f_terseLabel_en-US" xlink:label="lab_cenx_ContingentObligationDerivativeAsset" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contingent obligation &#8211; derivative asset</link:label>
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    <link:label id="lab_cenx_ContingentObligationDerivativeAsset_documentation_en-US" xlink:label="lab_cenx_ContingentObligationDerivativeAsset" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This amount represents the derivative asset recorded for the E.ON contingent obligation, which is defined as the sum of the carrying values as of the balance sheet date of the E.ON Contingent Obligation which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year or the normal operating cycle, if longer. The E.ON contingent obligation consists of the aggregate E.ON payments. Obligation to make repayments is contingent upon certain operating criteria. When the conditions for repayment are met, and for so long so those conditions continue to be met, there is obligation to make principal and interest payments.</link:label>
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    <link:label id="lab_us-gaap_LesseeOperatingLeasesTextBlock_a7706373-be5d-45a7-9f5d-a40d463b8434_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Leases</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeasesTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeasesTextBlock"/>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanServiceCost_a1b6492e-ee0f-4d3e-a84d-d5455e846280_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanServiceCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Service cost</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanServiceCost_ce02a47f-96b2-471f-9560-0d3d70123ac7_verboseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanServiceCost" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Service cost</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanServiceCost_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanServiceCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Service Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanServiceCost" xlink:to="lab_us-gaap_DefinedBenefitPlanServiceCost" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConcentrationRiskByBenchmarkAxis_60e115a5-64f3-44d4-a70b-2dcced597431_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Concentration Risk Benchmark [Axis]</link:label>
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    <link:label id="lab_us-gaap_CostOfGoodsAndServicesSold_5ac0a780-e800-425a-88fd-8c8047a801c3_terseLabel_en-US" xlink:label="lab_us-gaap_CostOfGoodsAndServicesSold" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cost of goods sold</link:label>
    <link:label id="lab_us-gaap_CostOfGoodsAndServicesSold_6fd3a1de-62df-4a15-bcac-ffc502f252b9_verboseLabel_en-US" xlink:label="lab_us-gaap_CostOfGoodsAndServicesSold" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cost of Goods and Services Sold</link:label>
    <link:label id="lab_us-gaap_CostOfGoodsAndServicesSold_label_en-US" xlink:label="lab_us-gaap_CostOfGoodsAndServicesSold" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cost of Goods and Services Sold</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSold" xlink:to="lab_us-gaap_CostOfGoodsAndServicesSold" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementEquityComponentsAxis_2635327a-ea02-47cb-9de1-36d6e011fd98_terseLabel_en-US" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Components [Axis]</link:label>
    <link:label id="lab_us-gaap_StatementEquityComponentsAxis_label_en-US" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Components [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementEquityComponentsAxis" xlink:to="lab_us-gaap_StatementEquityComponentsAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_UnderlyingDerivativeEnergyAvailable_5e66184f-091a-40a8-9914-954efcc68605_terseLabel_en-US" xlink:label="lab_cenx_UnderlyingDerivativeEnergyAvailable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Underlying, derivative energy, available</link:label>
    <link:label id="lab_cenx_UnderlyingDerivativeEnergyAvailable_label_en-US" xlink:label="lab_cenx_UnderlyingDerivativeEnergyAvailable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Underlying, Derivative Energy, Available</link:label>
    <link:label id="lab_cenx_UnderlyingDerivativeEnergyAvailable_documentation_en-US" xlink:label="lab_cenx_UnderlyingDerivativeEnergyAvailable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Underlying, Derivative Energy, Available</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_UnderlyingDerivativeEnergyAvailable" xlink:href="cenx-20201231.xsd#cenx_UnderlyingDerivativeEnergyAvailable"/>
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    <link:label id="lab_us-gaap_DebtInstrumentNameDomain_791ad9df-795a-487e-8f57-c1834e3a1e3d_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Name [Domain]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentNameDomain_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentNameDomain" xlink:to="lab_us-gaap_DebtInstrumentNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxAssetsGross_24e84980-21fd-4a14-965e-66e798bdf1ee_totalLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsGross" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total deferred tax assets</link:label>
    <link:label id="lab_us-gaap_DeferredTaxAssetsGross_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred Tax Assets, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsGross" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsGross" xlink:to="lab_us-gaap_DeferredTaxAssetsGross" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MinimumMember_f3533b53-8c14-4760-8579-2035fe3a8916_terseLabel_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Minimum [Member]</link:label>
    <link:label id="lab_srt_MinimumMember_label_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Minimum [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MinimumMember" xlink:to="lab_srt_MinimumMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BalanceSheetLocationDomain_936633c3-5e32-43cd-bdf2-08ed381955dd_terseLabel_en-US" xlink:label="lab_us-gaap_BalanceSheetLocationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Balance Sheet Location [Domain]</link:label>
    <link:label id="lab_us-gaap_BalanceSheetLocationDomain_label_en-US" xlink:label="lab_us-gaap_BalanceSheetLocationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Balance Sheet Location [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BalanceSheetLocationDomain" xlink:to="lab_us-gaap_BalanceSheetLocationDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment_00765d7c-5e45-4a75-a82c-d4f6ed724f48_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Loss on sale of BHH</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment_e0c279a3-23ba-4167-acb4-fc6da42fb2e5_negatedLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">BBH impairment</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Method Investment, Other than Temporary Impairment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment" xlink:to="lab_us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_CondensedFinancialStatementsTextBlock_3eeb4be4-e099-49fd-b482-4e7c1ffa48af_terseLabel_en-US" xlink:label="lab_srt_CondensedFinancialStatementsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Condensed Consolidating Financial Information</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedFinancialStatementsTextBlock" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedFinancialStatementsTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_CondensedFinancialStatementsTextBlock" xlink:to="lab_srt_CondensedFinancialStatementsTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation_65eb2595-04cb-4017-a297-42f656101c3b_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accumulated benefit obligation for plans with accumulated benefit obligations in excess of plan assets</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation"/>
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    <link:label id="lab_us-gaap_PlanAssetCategoriesDomain_36e7f89a-752e-4e6e-8e43-74bdd7538e0a_terseLabel_en-US" xlink:label="lab_us-gaap_PlanAssetCategoriesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Category [Domain]</link:label>
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    <link:label id="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_161690cc-6688-4287-9996-1cd3f2717e1a_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds from sale of property, plant and equipment</link:label>
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    <link:label id="lab_us-gaap_NumberOfReportableSegments_0fb4e826-1650-4a70-a421-2ea65e33f9e9_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfReportableSegments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of reportable segments</link:label>
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    <link:label id="lab_us-gaap_RetirementPlanTypeDomain_58c3fec5-2b72-4028-a11d-043c62af6131_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Retirement Plan Type [Domain]</link:label>
    <link:label id="lab_us-gaap_RetirementPlanTypeDomain_label_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Retirement Plan Type [Domain]</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable_c00d89a0-9467-4864-a061-6a986f9272a8_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Equity Method Investments [Table]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
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    <link:label id="lab_us-gaap_DebtInstrumentInterestRateEffectivePercentage_ee4df323-4cb7-43d7-b100-fce90fe1cc30_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Effective interest rate (percent)</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
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    <link:label id="lab_srt_ConsolidationItemsAxis_45d65b08-def5-4649-b990-eff7e4ce837b_terseLabel_en-US" xlink:label="lab_srt_ConsolidationItemsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Consolidation Items [Axis]</link:label>
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    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax_5fdd319d-d09b-43f0-8e9f-571f82189e82_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net gain (loss) arising during the period</link:label>
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    <link:label id="lab_us-gaap_NondesignatedMember_6d40f5f9-4841-4621-934f-bad6b0d342d3_terseLabel_en-US" xlink:label="lab_us-gaap_NondesignatedMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Not Designated as Hedging Instrument [Member]</link:label>
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    <link:label id="lab_cenx_ShareAndPerformanceBasedCompensationExpenseAbstract_fb7af0e0-aba0-441d-9b7b-9b3a4e71cdba_terseLabel_en-US" xlink:label="lab_cenx_ShareAndPerformanceBasedCompensationExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share and performance-based compensation expense [Abstract]</link:label>
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    <link:label id="lab_us-gaap_AccountsReceivableNetCurrent_03dfb7f4-2719-481b-890d-5157ff5b72d2_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsReceivableNetCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts receivable - net</link:label>
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    <link:label id="lab_us-gaap_MinorityInterestOwnershipPercentageByParent_f0d8dcd9-b215-4713-862e-0368911eba5a_terseLabel_en-US" xlink:label="lab_us-gaap_MinorityInterestOwnershipPercentageByParent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Ownership percentage</link:label>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_0c0a6529-116b-43ec-aee4-bbd65b346c96_totalLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total</link:label>
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    <link:label id="lab_us-gaap_GrossProfit_103da088-29b0-43fb-b0c2-9832ebcc0f28_totalLabel_en-US" xlink:label="lab_us-gaap_GrossProfit" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gross profit (loss)</link:label>
    <link:label id="lab_us-gaap_GrossProfit_dd312dd6-6fd4-4730-9620-cbcf380daf3b_terseLabel_en-US" xlink:label="lab_us-gaap_GrossProfit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gross profit (loss)</link:label>
    <link:label id="lab_us-gaap_GrossProfit_label_en-US" xlink:label="lab_us-gaap_GrossProfit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gross Profit</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_e717f674-ac9d-43ac-8f4c-e6e8af1e3d5e_verboseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, plant and equipment - net</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_35467681-6690-43de-860e-012a0208b4c3_totalLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, plant and equipment - net</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment, Net</link:label>
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    <link:label id="lab_srt_ReportableLegalEntitiesMember_22fcb029-54f8-4a2f-97d0-4d46b51866b0_terseLabel_en-US" xlink:label="lab_srt_ReportableLegalEntitiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reportable Legal Entities [Member]</link:label>
    <link:label id="lab_srt_ReportableLegalEntitiesMember_label_en-US" xlink:label="lab_srt_ReportableLegalEntitiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reportable Legal Entities [Member]</link:label>
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    <link:label id="lab_dei_EntityTaxIdentificationNumber_bb45c17a-8e2b-4eef-b89e-ccf4bd58537a_terseLabel_en-US" xlink:label="lab_dei_EntityTaxIdentificationNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Tax Identification Number</link:label>
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    <link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_8da8b15a-67bc-4c42-929b-8a679fd351df_terseLabel_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based compensation</link:label>
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    <link:label id="lab_us-gaap_NetIncomeLoss_e9e90eb0-00b0-4e5a-8eb8-ee56e3a4251e_totalLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net income (loss)</link:label>
    <link:label id="lab_us-gaap_NetIncomeLoss_27602d30-4290-48f6-a9c5-aa6c33185f15_verboseLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net income (loss)</link:label>
    <link:label id="lab_us-gaap_NetIncomeLoss_438d3f13-6871-482e-9061-318d88c489d8_terseLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net income (loss)</link:label>
    <link:label id="lab_us-gaap_NetIncomeLoss_label_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Income (Loss) Attributable to Parent</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="lab_us-gaap_NetIncomeLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_30c0afbf-0829-4f42-98fa-c6cb50a8d004_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Change in operating assets and liabilities:</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (Decrease) in Operating Capital [Abstract]</link:label>
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    <link:label id="lab_us-gaap_RepaymentsOfOtherShortTermDebt_92c541c9-68c9-4094-9bec-93fe7d4d2e4e_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfOtherShortTermDebt" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Repayment on other short-term borrowings</link:label>
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    <link:label id="lab_us-gaap_InventoryDisclosureTextBlock_2c133a0c-7947-4b71-85bc-2d4f2a57c547_verboseLabel_en-US" xlink:label="lab_us-gaap_InventoryDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inventories</link:label>
    <link:label id="lab_us-gaap_InventoryDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_InventoryDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inventory Disclosure [Text Block]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryDisclosureTextBlock" xlink:to="lab_us-gaap_InventoryDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LondonInterbankOfferedRateLIBORMember_0796b008-ab8c-4ab3-908b-e6858cf93c58_verboseLabel_en-US" xlink:label="lab_us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">LIBOR [Member]</link:label>
    <link:label id="lab_us-gaap_LondonInterbankOfferedRateLIBORMember_e43b6a8a-cec2-45cb-b20b-44c2de9a28a9_terseLabel_en-US" xlink:label="lab_us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">London Interbank Offered Rate (LIBOR) [Member]</link:label>
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    <link:label id="lab_us-gaap_DerivativeNonmonetaryNotionalAmountMass_f32932b4-da79-4c4a-a11b-6b5dd1c48a00_verboseLabel_en-US" xlink:label="lab_us-gaap_DerivativeNonmonetaryNotionalAmountMass" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative asset (in tones)</link:label>
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    <link:label id="lab_us-gaap_DerivativeNonmonetaryNotionalAmountMass_label_en-US" xlink:label="lab_us-gaap_DerivativeNonmonetaryNotionalAmountMass" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivative, Nonmonetary Notional Amount, Mass</link:label>
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    <link:label id="lab_cenx_LitigationSettlementAnnualInstallment_6d384573-7b4f-4434-b903-a898a18b3e86_terseLabel_en-US" xlink:label="lab_cenx_LitigationSettlementAnnualInstallment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Litigation settlement, annual installment</link:label>
    <link:label id="lab_cenx_LitigationSettlementAnnualInstallment_label_en-US" xlink:label="lab_cenx_LitigationSettlementAnnualInstallment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Litigation Settlement, Annual Installment</link:label>
    <link:label id="lab_cenx_LitigationSettlementAnnualInstallment_documentation_en-US" xlink:label="lab_cenx_LitigationSettlementAnnualInstallment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Litigation Settlement, Annual Installment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_LitigationSettlementAnnualInstallment" xlink:href="cenx-20201231.xsd#cenx_LitigationSettlementAnnualInstallment"/>
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    <link:label id="lab_dei_CurrentFiscalYearEndDate_ca74f982-0d25-42c1-9b3a-9ad7e8590e30_terseLabel_en-US" xlink:label="lab_dei_CurrentFiscalYearEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Current Fiscal Year End Date</link:label>
    <link:label id="lab_dei_CurrentFiscalYearEndDate_label_en-US" xlink:label="lab_dei_CurrentFiscalYearEndDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Current Fiscal Year End Date</link:label>
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    <link:label id="lab_cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationUnrealizedGainsLosses_bb70656a-6c54-4b06-b148-5ab4b6c782e8_terseLabel_en-US" xlink:label="lab_cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationUnrealizedGainsLosses" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Change in unrealized gains (losses)</link:label>
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    <link:label id="lab_cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationUnrealizedGainsLosses_documentation_en-US" xlink:label="lab_cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationUnrealizedGainsLosses" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Unrealized Gains (Losses)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationUnrealizedGainsLosses" xlink:href="cenx-20201231.xsd#cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationUnrealizedGainsLosses"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationUnrealizedGainsLosses" xlink:to="lab_cenx_FairValueNetDerivativeAssetLiabilityMeasuredonRecurringBasisUnobservableInputsReconciliationUnrealizedGainsLosses" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_SegmentReportingPrimaryAssets_348b76b9-fd2f-4149-916a-25256a6a3426_terseLabel_en-US" xlink:label="lab_cenx_SegmentReportingPrimaryAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Primary</link:label>
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    <link:label id="lab_cenx_SegmentReportingPrimaryAssets_documentation_en-US" xlink:label="lab_cenx_SegmentReportingPrimaryAssets" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Segment assets include cash and cash equivalents, accounts receivable, due from affiliates, prepaid and other current assets, inventory, intangible assets and property, plant and equipment-net; the remaining assets are unallocated corporate assets.</link:label>
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    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_20a3694c-3988-4c8d-a05c-1741773a3ebf_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accumulated Other Comprehensive Income (Loss) [Line Items]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ParentCompanyMember_e15fd957-e508-4791-8e98-4b342209e109_terseLabel_en-US" xlink:label="lab_srt_ParentCompanyMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The Company [Member]</link:label>
    <link:label id="lab_srt_ParentCompanyMember_label_en-US" xlink:label="lab_srt_ParentCompanyMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Parent Company [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ParentCompanyMember" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ParentCompanyMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ParentCompanyMember" xlink:to="lab_srt_ParentCompanyMember" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateofCompensationIncreaseYearOneAndThereafter_45d82cf0-1c30-4ee2-bcf7-6a39525bc205_terseLabel_en-US" xlink:label="lab_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateofCompensationIncreaseYearOneAndThereafter" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Rate of compensation increase, year one and thereafter</link:label>
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    <link:label id="lab_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateofCompensationIncreaseYearOneAndThereafter_documentation_en-US" xlink:label="lab_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateofCompensationIncreaseYearOneAndThereafter" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase, Year One And Thereafter</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateofCompensationIncreaseYearOneAndThereafter" xlink:href="cenx-20201231.xsd#cenx_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateofCompensationIncreaseYearOneAndThereafter"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateofCompensationIncreaseYearOneAndThereafter" xlink:to="lab_cenx_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateofCompensationIncreaseYearOneAndThereafter" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_223d62b8-00e1-4f6f-8a77-74ab36a6f2ba_terseLabel_en-US" xlink:label="lab_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">LIABILITIES:</link:label>
    <link:label id="lab_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_label_en-US" xlink:label="lab_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:to="lab_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InventorySuppliesNetOfReserves_a5643fa6-4bb4-4b35-afe4-324e142a9b64_terseLabel_en-US" xlink:label="lab_us-gaap_InventorySuppliesNetOfReserves" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating and other supplies</link:label>
    <link:label id="lab_us-gaap_InventorySuppliesNetOfReserves_label_en-US" xlink:label="lab_us-gaap_InventorySuppliesNetOfReserves" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inventory, Supplies, Net of Reserves</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventorySuppliesNetOfReserves" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventorySuppliesNetOfReserves"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventorySuppliesNetOfReserves" xlink:to="lab_us-gaap_InventorySuppliesNetOfReserves" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ForeignLineOfCreditMember_7b998d51-b172-480c-95cb-00e99c61d942_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignLineOfCreditMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Iceland revolving credit facility [Member]</link:label>
    <link:label id="lab_us-gaap_ForeignLineOfCreditMember_label_en-US" xlink:label="lab_us-gaap_ForeignLineOfCreditMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Foreign Line of Credit [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignLineOfCreditMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignLineOfCreditMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignLineOfCreditMember" xlink:to="lab_us-gaap_ForeignLineOfCreditMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_8d16015f-dc94-4ed0-95be-68fef57533ec_terseLabel_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental Cash Flow Information:</link:label>
    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_label_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental Cash Flow Information [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember_809b1e05-348d-4294-896c-b93da48d96db_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">U.S. equities</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Equity Securities, US [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember" xlink:to="lab_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_PensionContributionsAboveRequiredMinimumRemaining_94dbc3fd-b7c5-4fbb-993a-e8bd0c94e4f5_terseLabel_en-US" xlink:label="lab_cenx_PensionContributionsAboveRequiredMinimumRemaining" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Pension contributions above minimum remaining</link:label>
    <link:label id="lab_cenx_PensionContributionsAboveRequiredMinimumRemaining_label_en-US" xlink:label="lab_cenx_PensionContributionsAboveRequiredMinimumRemaining" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Pension Contributions Above Required Minimum, Remaining</link:label>
    <link:label id="lab_cenx_PensionContributionsAboveRequiredMinimumRemaining_documentation_en-US" xlink:label="lab_cenx_PensionContributionsAboveRequiredMinimumRemaining" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Pursuant to the terms of the settlement agreement with the Pension Benefit Guaranty Corporation, this amount represents the remaining additional contributions (above any minimum required contributions) to our defined benefit pension plans.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_cenx_PensionContributionsAboveRequiredMinimumRemaining" xlink:href="cenx-20201231.xsd#cenx_PensionContributionsAboveRequiredMinimumRemaining"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_cenx_PensionContributionsAboveRequiredMinimumRemaining" xlink:to="lab_cenx_PensionContributionsAboveRequiredMinimumRemaining" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentLineItems_860b58f3-4f17-4359-9567-04834d0be539_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment [Line Items]</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentLineItems_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_fa38e022-ea3b-4d54-9331-0110cf85cecc_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment, Type [Domain]</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-Lived Tangible Asset [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_f681735a-899d-4cf9-9d18-0f160a77c17c_negatedLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Benefits paid</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Benefits Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:to="lab_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DueToRelatedPartiesCurrentAndNoncurrent_e598bb9f-ae17-4b7c-bf24-d589c528925e_terseLabel_en-US" xlink:label="lab_us-gaap_DueToRelatedPartiesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Due to related parties</link:label>
    <link:label id="lab_us-gaap_DueToRelatedPartiesCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_DueToRelatedPartiesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Due to Related Parties</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueToRelatedPartiesCurrentAndNoncurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DueToRelatedPartiesCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DueToRelatedPartiesCurrentAndNoncurrent" xlink:to="lab_us-gaap_DueToRelatedPartiesCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTextBlock_69effe13-d2db-4fd1-bb61-255dbe4d39bc_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Summary of property, plant and equipment</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTextBlock_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_cenx_OtherPrimaryAluminumDeliveryCommitmentsAndContractsOpenPositionVolume_72810534-d567-41d1-9417-b04c5ff98830_terseLabel_en-US" xlink:label="lab_cenx_OtherPrimaryAluminumDeliveryCommitmentsAndContractsOpenPositionVolume" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other forward delivery contracts to sell primary aluminum (in tonnes)</link:label>
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    <link:label id="lab_cenx_OtherPrimaryAluminumDeliveryCommitmentsAndContractsOpenPositionVolume_documentation_en-US" xlink:label="lab_cenx_OtherPrimaryAluminumDeliveryCommitmentsAndContractsOpenPositionVolume" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total amount of primary aluminum committed to be supplied under existing contracts or agreements outside of major long-term supply commitments.</link:label>
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    <link:label id="lab_cenx_PowerAvailable_documentation_en-US" xlink:label="lab_cenx_PowerAvailable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The power currently available under the power purchase agreement.</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax_c22045df-b21e-4b77-989d-f91bb38d0333_totalLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total</link:label>
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    <link:label id="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_44fc322b-aca0-4639-85a4-db9a43d75541_negatedLabel_en-US" xlink:label="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Less accumulated depreciation</link:label>
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    <link:label id="lab_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings_e385d2ce-8499-4402-a8e6-f5d735d4cd2b_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Included in net income (loss)</link:label>
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    <link:label id="lab_cenx_StockRepurchaseProgramAdditionalAuthorizedAmount_dee074a6-89f5-430f-900b-1f00e2246881_terseLabel_en-US" xlink:label="lab_cenx_StockRepurchaseProgramAdditionalAuthorizedAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Additional repurchase amount</link:label>
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    <link:label id="lab_us-gaap_RelatedPartyTransactionsAbstract_b201dfa0-f6b8-4cb7-b56f-d80b6c634ddf_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party Transactions [Abstract]</link:label>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_65f413a0-9418-49e1-880c-b8764622df20_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of maturities of operating lease liability balances</link:label>
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    <link:label id="lab_us-gaap_RetainedEarningsMember_9c0d3c62-9e37-4718-8505-f34b9f047acc_terseLabel_en-US" xlink:label="lab_us-gaap_RetainedEarningsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accumulated deficit</link:label>
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    <link:label id="lab_us-gaap_ShortTermDebtTypeDomain_23721629-b8a6-4e83-b577-5b39e0b32560_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term Debt, Type [Domain]</link:label>
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    <link:label id="lab_us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList_e84c7e08-f77b-4403-8c48-f8a62e74c9e8_terseLabel_en-US" xlink:label="lab_us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Surcharge Imposed</link:label>
    <link:label id="lab_us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList_label_en-US" xlink:label="lab_us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Multiemployer Plan, Pension, Significant, Surcharge [Fixed List]</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_42c6b252-7085-4ff4-b608-8abebf8246bf_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment</link:label>
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    <link:label id="lab_cenx_DefinedContributionPlanAgeRequirementforFutureAccruals_3d4d3fe7-0009-4df9-962c-106ab89b5a41_terseLabel_en-US" xlink:label="lab_cenx_DefinedContributionPlanAgeRequirementforFutureAccruals" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Age requirement for future accruals</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_cenx_DefinedContributionPlanAgeRequirementforFutureAccruals" xlink:href="cenx-20201231.xsd#cenx_DefinedContributionPlanAgeRequirementforFutureAccruals"/>
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    <link:label id="lab_cenx_ShortTermPowerAgreementSupplyFromThirdPartyPercentage_56cefb16-e2b5-4a3f-929f-23255f8369ab_terseLabel_en-US" xlink:label="lab_cenx_ShortTermPowerAgreementSupplyFromThirdPartyPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term power agreement, supply from third party (percent)</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_cenx_ShortTermPowerAgreementSupplyFromThirdPartyPercentage" xlink:href="cenx-20201231.xsd#cenx_ShortTermPowerAgreementSupplyFromThirdPartyPercentage"/>
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    <link:label id="lab_us-gaap_IncreaseDecreaseInDueToRelatedPartiesCurrent_126abfb2-acdb-4bfa-a5be-c01e7cbb1216_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInDueToRelatedPartiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Due to affiliates</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInDueToRelatedPartiesCurrent" xlink:to="lab_us-gaap_IncreaseDecreaseInDueToRelatedPartiesCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TreasuryStockValue_26117e19-ae62-4690-81b6-8b178844d83f_negatedLabel_en-US" xlink:label="lab_us-gaap_TreasuryStockValue" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Treasury stock, at cost</link:label>
    <link:label id="lab_us-gaap_TreasuryStockValue_label_en-US" xlink:label="lab_us-gaap_TreasuryStockValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Treasury Stock, Value</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TreasuryStockValue" xlink:to="lab_us-gaap_TreasuryStockValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareTextBlock_8fd8b728-cd2e-4156-817f-a2592eb845a6_verboseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings (Loss) Per Share</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareTextBlock" xlink:to="lab_us-gaap_EarningsPerShareTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PensionPlansDefinedBenefitMember_73f996aa-f6e8-44a6-afca-6513ab5239f2_terseLabel_en-US" xlink:label="lab_us-gaap_PensionPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Pension</link:label>
    <link:label id="lab_us-gaap_PensionPlansDefinedBenefitMember_label_en-US" xlink:label="lab_us-gaap_PensionPlansDefinedBenefitMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Pension Plan [Member]</link:label>
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    <link:label id="lab_us-gaap_AssetRetirementObligationAccretionExpense_fbe5745b-04fa-40c3-aaf3-8be68598d8ad_terseLabel_en-US" xlink:label="lab_us-gaap_AssetRetirementObligationAccretionExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accretion expense</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:to="lab_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
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