2024年3月30日发(作者：错误代码651是什么意思)

Resources,ConservationandRecycling54 (2010) 1074–1083

ContentslistsavailableatScienceDirect

Resources,ConservationandRecycling

journalhomepage:/locate/resconrec

Physicalgeonomics:CombiningtheexergyandHubbertpeakanalysisfor

predictingmineralresourcesdepletion

AliciaValero

∗

,AntonioValero

CentreofResearchforEnergyResourcesandConsumptions,CIRCE,UniversityofZaragoza,MaríadeLuna3,Zaragoza50018,Spain

articleinfoabstract

Thispapershowshowthermodynamicsandinparticulartheexergyanalysiscanhelptoassessthe

degradationdegreeofearth’ourcesmaybephysicallyassessedasitsexergy

contentaswellastheexergyrequiredforreplacingthemfromacompletedegradedstatetothecon-

paper,ananalysisofthestateofour

tpurposeanexergyaccountingof51mineralshas

sallowedestimatingfromgeologicaldatawhen

ainedHubbert’sbell-

shapedcurvesofthemineralandfossilfuelscommoditiescannowberepresentedinanall-together

exergy–timerepresentationherenamedasthe“exergycountdown”.Thisshowsinaveryschematicway

theamountofexergults

showthatthepeakofproductionofthemostimportantmineralsmightbereachedbeforetheendof

nfirmstheHubberttrendcurvesformineralsobtainedbyotherauthorsusing

figuresmaychange,r,assuming

thatthesediscoveriesdouble,

rgyanalysisofmineralscouldconstituteauniversal

andtransparenttoolforthemanagementoftheearth’sphysicalstock.

© 2010 Elsevier B.V. All rights reserved.

Articlehistory:

Received14May2009

Receivedinrevisedform19January2010

Accepted24February2010

Keywords:

Exergy

Hubbertpeak

Scarcity

Fuelminerals

Non-fuelminerals

uction

The20thcenturyhasbeencharacterizedbytheeconomic

owthwasmainly

sustainedbythemassiveextractionanduseoftheearth’smineral

tance,onlyintheUSoverthespanofthelast

century,thedemandformetalsgrewfromalittleover160mil-

liontonstoabout3.3billiontons(MorseandGlover,2000).The

tendencyobservedworldwideinthepresent,isthatconsumption

willcontinueincreasing,especiallyduetotherapiddevelopmentof

Asia,thedesireforahigherlivingstandardofthedevelopingworld

physicallimitationsofour

r,inter-

tly,

mostattentionisfocusedratherontheconsequencesoftheuse

ofnaturalresources,suchasclimatechange,lossofbiodiversityor

pollutionofsoilsandrivers,-

ouslytheformerproblemsneedandareslowlybeingsolvedwith

internationalagreements,disseminationcampaigns,r-

more,thehugeamountofenergyreceivedeverydayfromthesun

(1353J/m

2

s)helpsrestoringatleastpartiallythedamagescaused

∗

Correspondingauthor.

E-mailaddress:aliciavd@().

0921-3449/$–seefrontmatter© 2010 Elsevier B.V. All rights reserved.

doi:10.1016/rec.2010.02.010

tothebiosphere,ontrary,the

naturalrepositionofthegeosphere,whichcomesmainlyfromthe

earth’sinteriorenergy(0.034–0.078J/m

2

s—Skinneretal.,1999),is

closetozerowhencomparedtothatoftheotherexternalearth’s

spheres.

AsdiscussedinValeroandValero(2010),duringmillionsof

years,naturehasformedandconcentratedmineralsthrougha

largenumberofgeologicalprocessessuchasmagmaticseparation,

hydrothermal,sedimentary,residual,etc.(ChapmanandRoberts,

1983)cen-

tratedmineraldepositsserveasamaterialandfuelreservoirfor

moreconcentratedisamineraldeposit,theless

ingofmaterialsimplies

anobviousreductionofthenaturalstockintermsofthemin-

eralsextractedfromtheminesandthefossilfuelsrequiredfor

xtractedmineralsareconcentrated

andfurtherrefinedtoobtainthedesiredrawmaterials,forwhich

y,

thenaturalstockstoredintheearth’scrustgoesintothehands

eusefullifeofproducts

finishes,theybecomedispersed,endingupaswastes(eitheraspol-

lutionordisposedofinlandfills).AsGordonetal.(2006)argue,

therelativesizesoftheremainingstockinthelithosphereand

thestocktransferredtowastesatanygiventimearemeasures

ofhowfarwehaveprogressedtowardtheneedfortotalreliance

,/Resources,ConservationandRecycling54 (2010) 1074–10831075

onrecyclingratherthanonvirginoretoprovidematerialfornew

products.

Unfortunately,theSecondLawofThermodynamicsreflectedin

Eq.(2),tellsusthatastheconcentrationoftheresourceinthe

earth’scrusttendstozero,theenergyrequiredtoextractthemin-

eraltendstoinfiuently,fromapracticalpointofview,

itisimpossibletorecoverresourcesagainwhentheybecomedis-

verydistantfuture,itwillbeeasiertoextractmetals

fromlandfillsthanfromthecrust.

silfuelsor

manyadditiveslikeCr,Mo,Mninsteelorinpaints,orthenewage

ofhigh-techmetalssuchasIn,Ge,Ta,edinnanotechnol-

ogyandmicroelectronicsareimpossibleorextremelydifficultto

scu-Roegen,

1

fatherofecologicaleconomists,states

thatwecanonlyrecycle“carbojunk”.Thatmeansthatwecannot

rmore,theworldwiderushforstrate-

gicmaterialsiscausingdramaticconsequencesinlessdeveloped

countriessuchasirreversibleenvironmentaldamage,corruption

fectisnamedbyHumphreysetal.(2007)as

the“naturalresourcescurse”.

Ourtechnologyisquiteinefficientintheuseofenergyandmate-

rials,urces

arelimited,s

impossibletomanageefficientlytheresourcesonearth,ifwedonot

,

weneedmanagementtools,accountabilityandpoliticalwillto

ractiveIndustriesTransparencyInitiative

(2006)isbecominganinternationallyacceptedstandardforeco-

nomictransparencyintheoil,s

stillinsufficient,sincephysicalandobjectiveinformationabout

theremainingresourcessuchasoregrades,quantityofenergyand

waterrequiredforextraction,theamountofwasterockandother

physicalparametersthatwouldallowanobjectiveanalysisofour

mineralcapitalisrarelypublished.

Rationalmanagementtoolsfortheefficientuseofresources

requireatheoreticalbasis,naturallyprovidedbythermodynamics.

Forathermodynamicist,thisissoobvious,thatitishardtobelieve

of

theSecondLawthroughtheexergyconcept,allowstoprogressinto

tscanbeconvertedintonum-

bers,ective

ofthispaperistocontributetoputSecondLawnumberstothe

naturalresourcesdepletionandinparticulartomineralresources.

Georgescu-Roegenwasoneofthefirstauthorsinrealizingthe

linksbetweentheeconomicprocessandtheSecondLawofthermo-

eminalworkTheEntropyLawandtheEconomic

Process(Georgescu-Roegen,1971),hestatesthat“theentropylaw

itselfemergesasthemosteconomicinnatureofallnaturallaws[...]

andthislawisthebasisoftheeconomyoflifeatalllevels”.More

authorssuchasBerryetal.(1978),Ruth(1995)orRoma(2006)and

RomaandPirino(2009)statethateconomicproductionprocesses

shouldconsiderthermodynamiclimitsonmaterialandenergyuse

tal.(1978)developed

atheoremforfixingtheeconomically-efficientlevelofthermody-

namiceffiample,Ruth(1995)

determinedtheoptimalextractionpathandproductionofironore

ateachperiodoftime,takingintoaccountthermodynamiclimitson

materialandenergyefficiency,thetreatmentoftechnicalchange

throughthetheoryoflearningcurvesandtheevaluationofalterna-

tivetimepathsfromaneconomicandthermodynamicperspective.

Roma(2006)andRomaandPirino(2009)developeddifferentmod-

elsforproductionprocesses,imposingenergyratherthanstandard

1

SeetheinterviewofAntonioValerowithNicholasGeorgescu-Roegenunder:

/boletin/n4/.

ult,theauthors

statethatresourceswillbemoreefficientlyused,reducingthereby

entropicwastes.

Parallelly,concernedenvironmentalistssearchforalternate

oraof

measuringunits(ornumeraires)appear,almostoneperindica-

icular,thosewhoaccountformineralsandfossilfuels,

haveaspectrumofdefinitionsandmeasurementunitsthatactu-

allyimpedetomakeasystematicanduniversallyacceptedaccount

ofwhattheearth’scrustprovidesannuallyandwhatremains.

Ontheotherside,itisobviousthatmoneycannotbethebest

unitofmeasurefortheassessmentofresources,sincecurrency

changesfromonecountrytoanother,itsvaluedependsondif-

ferentfactorsandmoreover,itisimpossibletoquantifynaturein

monetaryterms,

canbecompensatedwithcounteractionslikerecovering,restoring

andreplacingtechniqueswhichobviouslyhaveanassociatedcost.

rtheyaredifficult

toadmit,

argumentthecostisnotmeasuredwithmoneyoreverythingcosts

morethanthemoneywepayshouldbeplacedovereverythingcan

bebought.

So,whichshouldbetheunitofmeasureofcost?Theanswerto

thisquestionisintheSecondLawofThermodynamics:ifthecostis

asacrificeofresources,andthealreadyconsumedresourceshave

beenconsumedforever,onecandeducethatweshouldseethisfact

field,Thermody-

namicsprovidestoolssuchasenergy,entropyorexergy,among

blemwithenergyisthatitdoesnotdistinguish

quality.

Althoughexergyisalsoone-dimensional,itissensibleto

quantityandqualityoftheinterchangedenergyandhasenergy

,exergymeasurestheminimumquantityofuse-

fulenergyrequiredtoprovideasystemforbuildingitfromits

constituentelementsfoundinthereferenceenvironment(R.E.).

Thereferenceenvironmentisahypotheticalandhomogeneous

earth,whereallsubstanceshavebeenreactedandmixed,without

kineticorpotentialenergyandatambientpressureandtempera-

ture.

ndefined,theminimumthermodynamic

costorexergyofanymaterialorenergyfl

isveryimportant,asexergytakesintoaccountallphysicalmanifes-

tationsthatdifferentiatethesystemfromitsenvironment:height,

velocity,pressure,temperature,chemicalcomposition,concentra-

tion,sisnotafunctionofhowmuchweappreciate

things,butontheusefulenergythatcanbereleaseduntilitsdeple-

therhand,theexergyconceptparticipatesinall

propertiesofthecostconcept:itisadditiveandcanbecalculated

processshouldbeconsidered

asreversibleinallitssteps.

Themostimportantcontributionoftheexergyconceptisinits

abilitytoobjectifyallthephysicalmanifestationsinenergyunits,

duct,naturalorarti-

ficialresource,productiveprocessorpollutingemissioncanbe

whyagoodnumberof

researchersbelievethatexergycancontributetotheassessmentof

certainenvironmentalconcerns(Szargut,2005,Brodianski,2005,

Wall,1977,Sciubba,2003,orAyresetal.,2004).

ticalbackground

Themostimportantfeaturesthatfixthevalueofamineral

resourceareononehanditschemicalcompositionandontheother

handitsconcentration—bothcharacteristicswhichcanbeassessed

withthesingleindicatorofexergy.