麦肯锡 -清理混合废料：借助循环模式实现铝产业脱碳 Cleaning up mixed scrap Decarbonizing aluminum through circularity

Mcsey

&company

Cleaningupmixedscrap:Decarbonizingaluminumthroughcircularity

Theenergytransitionisleadingtoincreaseddemandforaluminum.Recoveringspecificalloysfrommixedscrapcouldplayacriticalroleinachievingnet-zeroemissionsandimprovingcircularity.

ThisarticleisacollaborativeeffortbyPeterSpillerandToralfHagenbruch,withIlanaKochetkova,MadickeEmbrechts,PatriciaBingoto,andVladislavVasilenko,representingviewsfromMcKinsey’sEnergy&MaterialsPractice

November2025

Cleaningupmixedscrap:Decarbonizingaluminiumthroughcircularity2

Executivesummary

Aluminumisamajorbuildingblockoftraditionalindustries,suchasconstructionandpackaging,aswellasthenet-

zerotransition.1Aluminumisessentialforlow-carbon

applications,suchaselectricvehicles(EVs),renewable-

energytechnologies,solarphotovoltaics(PV),wind

turbines,andrelatedelectricitytransmission.Thatsaid,

theproductionofprimaryaluminum²isenergy-intensive

andcanresultinsignificantCO₂emissionswhenusing

fossilfuel–basedelectricity.Furthermore,emissionsfromtheconsumptionofcarbonanodesduringelectrolysisareparticularlydifficulttoabate,andupstreamproductionandrefiningprocessesforprimaryaluminum(whichrequire

theuseofcoal,heavyfueloil,ornaturalgas)canleadtosignificantembeddedemissions.³

Althoughaddressingtheconsumptionoffossilfuelsin

theproductionofprimaryaluminumremainsimportant,

recyclingaluminum,especiallyfrompostconsumerscrap,couldbeamoreefficientandfastergatewaytoachievingnet-zeroemissionsbecauseitrequiresonly5percentoftheenergyneededforprimaryproduction.Momentum

forsecondaryaluminumisbuilding.Onthedemand

side,majorcustomersintheautomotiveandpackaging

industriesaresettinghighrecycled-contenttargetsfor

materials,includingaluminum.Andonthesupplyside,

regulationssuchastheCriticalRawMaterialsActinthe

EuropeanUnionandtheInflationReductionActinthe

UnitedStatesarepromotingthedevelopmentofsecondary-

aluminumcapacitythroughimprovedrecyclingtargetsandinvestmentsinsecondary-materialscapacity.

Thisarticleispartofaseriesonincreasingthecircularityofmaterials.Totapthegrowingsecondary-aluminummarket,recyclersandcustomersaimingforcircular,lower-carbon

aluminumcantacklecollectionandsortationbottlenecksinthealuminumvaluechaintoboostrecyclingratesandstepuptherecoveryandpreservationofhigh-valuealloys.

1Formoreonthepathtonetzero,see“Thenet-zerotransition:Whatitwouldcost,whatitcouldbring,”McKinsey,January2022.

2Primaryaluminumisaluminumproducedfromextractingbauxite,refiningalumina,andextractingaluminumfromthesmeltingprocess;secondaryaluminumisproducedfromtherecyclingofaluminumscrap.

3Aluminumdecarbonizationatacostthatmakessense,MissionPossiblePartnership,April2023.

Aluminumdemandisexpectedtogrowbymorethan2percentperannuminthenextdecade

From2025to2035,globaldemandforaluminumis

expectedtoincreasefromapproximately106to130millionmetrictons(Mt),withdemandmainlyresultingfromgrowthinenergytransitionapplicationsandtraditionalend-use

segments,withaCAGRof2.1percentperannum.

Thisincreaseindemandwillmainlystemfromgrowthintheautomotiveindustryandtheaforementionedenergyapplications(anincreaseof15Mt)aswellasincreasedadoptionofEVs,whichtypicallyhavehigheraluminumcontentthaninternalcombustionenginevehicles.

Themajorityofgrowthonthesupplysidecouldcomefromsecondaryaluminum,mainlydrivenbygreateravailability

ofpostconsumer-scrapvolumesinChina.Atthesametime,primaryproductionwilllikelyaccountforabout30percentofsupplygrowth,basedonthecommittedprojectpipeline.

Theenergytransitioncouldleadtoincreasedaluminumdemand,withasupply–demandgapoffourmillionmetrictonsby2035.

Globaltotaldemandandsupply,¹2025–35,millionmetrictons

PrimarysupplySecondarysupplyTotaldemand

106

130

106

5

48

78

Totalsupply(primaryandsecondary)Totaldemand

105

32

73

ChinaRestof

world

8

16

2035supply–demandgap

Secondarygrowth

Primarygrowth

2035demand

2025demand

2035supply

2025supply

130

126

16

4

1Supplyaccountsforannouncedcapacityclosuresandcurtailments.

Source:InternationalAluminiumInstitute;MineSpansAluminumQ22025

Cleaningupmixedscrap:Decarbonizingaluminiumthroughcircularity3

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Optimizingcircularaluminumvaluechainscouldbolstersupply

Thefollowingfeedstocksofsecondarymaterialscanhelpsupportincreaseddemand:

1.Preconsumerscrap.Aluminumscrapcomingfrom

casting,semiproduction,andfabricationaccounts

forapproximatelyone-thirdoftheglobalscrappool.4Thesevolumestypicallyhavehighratesofcollectionandcanbedirectlyremelted.

2.Postconsumerscrap.Aluminumscrapcomingfromend-of-lifeapplicationsaccountsfortheremainingtwo-thirdsofglobalscrap.5Postconsumerscrap

requiresadequatecollectionaswellasfurtherstepsforsortationandshreddingbeforeitcanberefinedandmeltedforreuse.

4“Post-consumeraluminiumscraptops20milliontonnesforthefirsttime,”InternationalAluminiumInstitute,May25,2021.

5“Post-consumeraluminiumscraptops20milliontonnesforthefirsttime,”InternationalAluminiumInstitute,May25,2021.

Aluminumscrapcanberecoveredthroughoutthevaluechain,frommanufacturingtoend-of-lifeproducts.

Overviewofthealuminumvaluechain

Mostmaterialrecovered;significantdowncycling

Determinessecondarymaterialquality

Refiningandmelting

Sortingandshredding

Secondaryvaluechain

Secondarysupply

Postconsumerscrap

Preconsumerscrap

Variesbyregion

Collection

Productionstep

Downstream

Semiproduction

Materialfiow

Fabrication

Midstream

Aluminumsmelting

Upstream

Bauxitemining

Primary

valuechain

Aluminarefining

Formatcasting

Source:InternationalAluminiumInstitute;MetalBulletin;USGeologicalSurvey

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Thehighshareofmixedscrapisakeychallengeforaluminumrecycling

Inmanufacturingprocessesandproducts,aluminumisoftencommingled,makingitdifficulttorecoverandpreservespecificalloys.Inmanycases,thiscanlimitrecyclingofmixedscrapandcastalloys.

Preconsumerscrapaccountsforaboutone-thirdoftotal

scrapvolume,whiletheremainingvolumescomefrom

postconsumerscrap.Withcurrentindustrypractices,a

largeshareofpostconsumerscrapisnotsegregated

andendsupinmixed-scrappools,whereitiseventually

downcycled,withoutspecifichigh-valuealloysbeing

recovered.Forexample,6xxx-seriesalloys(classifiedby

theirmagnesiumandsiliconcontentandwhichweestimatemayreachatotaldemandofabout34Mtin2035)seelowerratesofrecyclingandaremostlyusedin7xxx-seriesorcastalloys,whichcanhandleahighershareofimpurities.

WiththegrowingshareofEVs,mixedscraptraditionally

usedincastalloysforinternalcombustionengineblocks

couldseeitsdemandreducedalongwiththedeclineof

automotivecastings,resultinginaneedtoimprovesortationandrecyclingpractices.

Alargeshareofrecoveredaluminumisgradedasmixedscrap.

Shareofaluminumscrapcomposition,bycategory,%

68

TotalscrapPreconsumerPostconsumerSegregatedSegregatedMixedscrap

scrapscrapcastingscrapwroughtscrap

Majorityoftotal

scrapwith

potentialregardingcollectionrates

Tighteralloytolerances,canbereused(eg,beverage

cans,heatexchangers,extrusionparts)

3

100

Highly(+90%)

collectedand

recovered(technicallimitsarepushed)

34

Broaderalloy

tolerances,mainlyusedforengineblocksandtransmissionhousings

13

51

Note:Figuresmaynotsumtototals,becauseofrounding.

Cleaningupmixedscrap:Decarbonizingaluminiumthroughcircularity5

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Althoughaluminumisalreadyhighlyrecycledtoday,therearelargediscrepanciesbetween

regionsandgradesofalloy

Collectionandrecoveryratesofaluminumscrapvaryacrossregionsandscrapsources.

Preconsumerscraphashighratesofcollectionandrecovery,primarilybecauseofitshighvalueandtherelativelylimiteddiversityinthescrapflow.

Bycontrast,postconsumerscraphascomparativelylargercollectionandrecoverylosses,althoughdifferences

existacrossend-usesegmentsandregions.Forexample,collectionratesinbeveragepackagingvarysignificantly

fromcountrytocountry,rangingfrom75percentinthe

broaderEuropeanUnionto99percentinGermany.6For

othertypesofpackaging,suchasaluminumfoil,collectionislowanddifficulttoimplement,andmaterialcanoftengetlostinmunicipalwaste.

6“Recordnumberofusedaluminiumbeveragecansrecycledasindustrydrivestoward100%circularityby2050,”EuropeanAluminium,February10,2025.

Mixedscrapaccountsforaroundhalfofthetotalavailablealuminumscrap.

Globalaluminumscrapsupplypergrade,2035,millionmetrictons

PostconsumerscrapPreconsumerscrapMixedscrap

~70%

1xxx

Packaging

Batteries(ie,cathodefoils)

5xxx

Automotive

BeveragecanlidsConstruction

6xxx

AutomotiveConstructionMachinery

7xxx

Aerospace

AutomotiveConstruction

GradesCollectedand

(useexamples)Scrappool¹UncollectedUnrecoveredrecovered¹Mixedscrap

8.2

13.7

11.1

5.1

11.92.8

0.9

6.91.20.6

6.7

1.5

21.9

14.9

2.71.1

~80%

~60%

~70%

4.9

8.9

3.6

9.7

1Includingbothpreconsumerandpostconsumerscrap.Source:McKinseyMetalSpansandMineSpans

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Inadditiontotacklingthechallengesofmixed-scrappools,improvingcollectionandrecoveryratescouldleadtoadditionalopportunitiestoimproveoverallrecyclingrates

Inspecificregions,suchasChinaandNorthAmerica,thereispotentialtoincreasecollectionrates.For5xxx-series

alloys,whicharemainlyusedintransportationandbuildingstructures,approximately6.2Mtofaluminumcouldremainuncollectedby2035.

Regulationsandimprovedinfrastructurecouldincrease

usablescrappoolsandsubsequentlyimprovecollections

rates.Doingsowouldlikelyentailseparatemunicipaland

industrialwastecollectionschemes,whichcouldreducetheshareofaluminumscrapthatiscollectedbutunrecovered.

Therearesignificantpoolsofuncollectedandunrecoveredaluminumacross5xxx-seriesalloys,mainlyinChinaandNorthAmerica.

Estimateduncollectedandunrecoveredpostconsumerscrap,2035,thousandmetrictons

Size100UncollectedCollectedbutunrecovered

ConstructionTransportationMachineryEnergyAppliancesPackagingOther

China

CIS¹

DevelopedAsia²

Eastern

Europe

India

Latin

America

MENA³

North

America

Oceania

OtherAsia⁴

Sub-SaharanAfrica

Western

Europe

Collectionand

recoverydynamics

Highcollectionratesduetohighabsolutevolume(demand)

Lowvolumesonuncollectedandverylowvolumesoncollectbutunrecoveredscrap

End-of-lifecanlidswithlowcollectionrates

Unrecovered:1,200kt

Uncollected:6,200kt

1CommonwealthofIndependentStates(Armenia,Belarus,Kazakhstan,Kyrgyzstan,Moldova,Russia,Tajikistan,andUzbekistan).2IncludingJapanandSouthKorea.

3MiddleEastandNorthAfrica.

4IncludingIndonesia,Thailand,andVietnam.

Cleaningupmixedscrap:Decarbonizingaluminiumthroughcircularity7

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Recoveringspecificalloysfrommixedscraprequiresimprovedsortingpractices

Today,mostmixedscrapiseitherexportedformanual

sortinginbest-costlocationsordowncycledwithout

specific,high-valuealloysbeingrecovered.Advanced

sortationandrepurificationcanhelpaddressthischallenge.

Ofthetwo,advancedsortationisalreadycost-competitive,butitrequiressignificantworkandcommitmenttolaunch

atscale.Anexemplaryadvanced-sortingprocessentails

producingtwitch(akeyrawmaterial)fromZorba7through

acombinationoftechnologies—X-rayfluorescence,

X-raytransmission(XRT),andlaser-inducedbreakdown

spectroscopy—thatseparatelightandheavyfractions.Fromthere,aluminumscrapcouldbesortedintocastalloysand

individualwroughtalloys(suchas5xxxor6xxx),reducingtheshareofdowncycledaluminum.Withtoday’stechnologies,ascaleof30,000to40,000metrictonsofscrapperannum

couldallowprocessingcostsofabout$200to$300per

metricton8andcreateapositivebusinesscasewithamarginof$50to$150permetricton—withhigher-valuemetal

fractionsoffsettingtheadditionalprocessingefforts.

Bycontrast,repurificationtechnologiescouldhelpproduce1xxx-seriesalloys.However,repurificationandother

technologiestypicallyconsumemoreenergyandareatearlierstagesofdevelopmentthanothertechnologies.

Althoughadvancedsortingtechnologyhasprogressed

significantlyoverthepastfewyears,settingupsuchcircularvaluechainsremainschallenging,andthereissignificant

potentialforgreaterefficiency.Movingforward,tackling

mixedscrapcouldbenefitfromcollaborativeapproachestoalignstakeholdersacrosslocalvaluechains.Suchalliancescanhelppoolresources,shareknowledge,andinvestin

advancedtechnologies,whichcouldthereforestreamline

7Zorbafraction,shreddednonferrousscrapfraction,mainlyconsistingofaluminum,butitcancontainothernon-ferrousfractions(brass,zinc,nickel,andcopper).

8ThefullprocessingcostaccountsforZorba,lightandheavysortingusingXRT,alloy-levelsortingusingLIBS,andothercosts,suchaslogisticsandhandling.

Improvingcircularityinaluminumrequiresaddressingmixedscrapalongtheentirevaluechain.

EddyXRTandXRTand

currentXRF¹XRF

HeavyCast

metalsaluminum

Fine

Zorba

Wroughtaluminum

LIBS²

5xxx,6xxx

Coarse

fractionMediumgrain

Undersize

Screening

Screening

Oversizemanualsorting

Postconsumervehiclesscrap

ZorbaTwitch

Eddycurrent

Traditionalroute

1X-raytransmissionandX-rayfiuorescence.2Laser-inducedbreakdownspectroscopy.

Cleaningupmixedscrap:Decarbonizingaluminiumthroughcircularity8

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operations,acceleratelearningcurves(subsequently

reducingcosts),andimprovetheoverallefficiencyof

therecyclingprocess.Throughback-to-backofftake

agreementsandsynergeticcommercialmodels,alliancescouldalsohelpensurethatpartnerscommitoverthelongterm,whichisparticularlyimportantwhensecuringa

continuousflowofscrapmaterials.

Anumberofrecentalliancesdemonstratethepotential

ofpartnershipstotacklethesechallenges.Forexample,

Constellium’scollaborationwithOSRisworkingon

enhancements