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小水媛媛
2011-04-16 0人阅读 举报 0 0 暂无简介

简介:本文档为《2pdf》,可适用于工程科技领域

MineralProcessingTechnologyAnIntroductiontothePracticalAspectsofOreTreatmentandMineralRecovery,byBarryAWills,TimNapierMunn·ISBN:·Publisher:ElsevierScienceTechnologyBooks·PubDate:OctoberPrefacetothEditionAlthoughminingisaconservativeindustry,economicdriverscontinuetoencourageinnovationandtechnologicalchangeInmineralprocessing,equipmentvendors,researchersandtheoperationsthemselvesworktodeveloptechnologiesthataremoreefficient,oflowercostandmoresustainablethantheirpredecessorsTheresultsareapparentinnewequipmentandnewoperatingpracticeAnytextbookneedstoreflectthesechanges,andBarryWills'classicisnoexceptionItisnearlyyearssinceMineralProcessingTechnologywasfirstpublished,andithasbecomethemostwidelyusedEnglishlanguagetextbookofitskindThesixtheditionappearedinandBarryandhispublishersfeltthatitwasagaintimetobringthetextuptodateTheyapproachedtheJuliusKruttschnittMineralResearchCentreattheUniversityofQueenslandtotakeonthechallengingtaskMycolleaguesandIagreedtodosowithsometrepidationThebook'swelldeservedreputationandutilitywereatstake,andthemagnitudeofthetaskwasclearRevisingsomeoneelse'stextisnotaneasythingtodosuccessfully,andtherewasarealdangerofthrowingthebabyoutwiththebathwaterThevalueofMineralProcessingTechnologyliesinitsclearexpositionoftheprinciplesandpracticeofmineralprocessing,withexamplestakenfrompracticeIthasfoundfavourwithstudentsofmineralprocessing,thosetrainedinotherdisciplineswhohaveconvertedtomineralprocessing,andasareferencetocurrentequipmentandpracticeItwasimportantthatitsappealtothesedifferentcommunitiesbepreservedandifpossibleenhancedWethereforeadoptedthefollowingguidelinesinrevisingthebookThetheditionisindeedarevision,notacompleterewriteThisdecisionwasbasedontheviewthat"ifitain'tbroke,don'tfixit"Eachdiagram,flowsheet,referenceorpassageoftextwasconsideredasfollowsIfitreflectedcurrentknowledgeandpractice,itwasleftunchanged(ormodestlyupdatedwherenecessary)Ifithadbeenentirelysuperseded,itwasremovedunlesssomeusefulprincipleorpieceofhistorywasbeingillustratedWheretheintroductionofnewknowledgeorpracticewasthoughttobeimportanttopreservethebook'scurrency,thiswasdoneAsaconsequence,somechaptersremainrelativelyunscathedwhereasothershaveexperiencedsubstantialchangesAparticularproblemarosewiththeextensivereferencestoparticularmachines,concentratorsandflowsheetsWherethepointbeingillustratedremainedvalid,theseweregenerallyretainedintheinterestofminimisingchangestothestructureofthebookWheretheywereclearlyoutofdateinamisleadingsenseandorwherealternativedevelopmentshadattainedthestatusofcurrentpractice,newmaterialwasaddedItisperhapsameasureofBarryWills'originalachievementthatithastakenmorethanadozenpeopletopreparethislatesteditionIwouldliketoacknowledgemygratitudetomycolleaguesattheJKMRCandelsewhere,listedbelow,forsubscribingtheirknowledge,experienceandvaluabletimetothisgoodcausedoingsohasnotbeeneasyEachchapterwashandledbyaparticularindividualwithexpertiseinthetopic(severalindividualsinthecaseofthelargerchapters)ImustalsothanktheeditorialstaffatElsevier,especiallyMirandaTurnerandHelenEaton,fortheirsupportandpatience,andBarryWillsforhisencouragementoftheenterpriseMyjobwastocontributesomeofthechapters,torestrainsomeofthemoreidiosyncraticstylisticextravagancies,andtohelpmakethewholethinghappenTomisquotethegreatcomicgeniusSpikeMilligan:thelasttimeIeditedabookIsworeIwouldneverdoanotheroneThisisitTimNapierMunnDecemberContributorsChapters,,,,ChaptersandChapterChaptersandChapterChapterChapters,andChapterAppendixIIIProfTimNapierMunn(JKMRC)DrGlenCorder(JKTech)DrRobMorrison(JKMRC)andDrMichaelDunglison(JKTech)DrToniKojovic(JKMRC)DrFrankShi(JKMRC)MarkoHilden(JKMRC)andDeanDavid(GRDMinproc,formerlywithJKTech)DrPeterHoltham(JKMRC)DrDanAlexander(JKTech),DrEmmyManlapig(JKMRC),DrDeeBradshaw(DeptChemicalEngineering,UniversityofCapeTown)andDrGregHarbort(JKTech)DrMichaelDunglison(JKTech)AcknowledgementsSecretarialassistanceOtheracknowledgementsVynetteHollidayandLibbyHill(JKMRC)ProfJPFranzidis(JKMRC)andEvieFranzidisfortheirworkonanearlierincarnationofthisprojectDrAndrewThorntonandBobYenchofMipacforhelpwithaspectsofprocesscontrolTheJuliusKruttschnittMineralResearchCentre,TheUniversityofQueensland,foradministrativesupportThelogosoftheUniversityandtheJKMRCarepublishedbypermissionofTheUniversityofQueensland,theDirector,JKMRCTableofContentsIntroductionOrehandlingMetallurgicalaccounting,controlandsimulationParticlesizeanalysisComminutionCrushersGrindingmillsIndustrialscreeningClassificationGravityconcentrationDensemediumseparation(DMS)FrothflotationMagneticandelectricalseparationOresortingDewateringTailingsdisposalAppMetallicoremineralsAppCommonnonmetallicoresAppExcelspreadsheetsforformulaeinchapterIntroductionMineralsandoresMineralsTheformsinwhichmetalsarefoundinthecrustoftheearthandasseabeddepositsdependontheirreactivitywiththeirenvironment,particularlywithoxygen,sulphur,andcarbondioxideGoldandplatinummetalsarefoundprincipallyinthenativeormetallicformSilver,copper,andmercuryarefoundnativeaswellasintheformofsulphides,carbonates,andchloridesThemorereactivemetalsarealwaysincompoundform,suchastheoxidesandsulphidesofironandtheoxidesandsilicatesofaluminiumandberylliumThenaturallyoccurringcompoundsareknownasminerals,mostofwhichhavebeengivennamesaccordingtotheircomposition(eggalenaleadsulphide,PbSsphaleritezincsulphide,ZnScassiteritetinoxide,SnO)MineralsbydefinitionarenaturalinorganicsubstancespossessingdefinitechemicalcompositionsandatomicstructuresSomeflexibility,however,isallowedinthisdefinitionManymineralsexhibitisomorphism,wheresubstitutionofatomswithinthecrystalstructurebysimilaratomstakesplacewithoutaffectingtheatomicstructureThemineralolivine,forexample,hasthechemicalcomposition(Mg,Fe)SiO,buttheratioofMgatomstoFeatomsvariesindifferentolivinesThetotalnumberofMgandFeatomsinallolivines,however,hasthesameratiotothatoftheSiandOatomsMineralscanalsoexhibitpolymorphism,differentmineralshavingthesamechemicalcomposition,butmarkedlydifferentphysicalpropertiesduetoadifferenceincrystalstructureThus,thetwomineralsgraphiteanddiamondhaveexactlythesamecomposition,beingcomposedentirelyofcarbonatoms,buthavewidelydifferentpropertiesduetothearrangementofthecarbonatomswithinthecrystallatticeTheterm"mineral"isoftenusedinamuchmoreextendedsensetoincludeanythingofeconomicvaluewhichisextractedfromtheearthThus,coal,chalk,clay,andgranitedonotcomewithinthedefinitionofamineral,althoughdetailsoftheirproductionareusuallyincludedinnationalfiguresformineralproductionSuchmaterialsare,infact,rocks,whicharenothomogeneousinchemicalandphysicalcomposition,asareminerals,butgenerallyconsistofavarietyofmineralsandformlargepartsoftheearth'scrustForinstance,granite,whichisoneofthemostabundantigneousrocks,iearockformedbycoolingofmoltenmaterial,ormagma,withintheearth'scrust,iscomposedofthreemainmineralconstituents,feldspar,quartz,andmicaThesethreehomogeneousmineralcomponentsoccurinvaryingproportionsindifferentpartsofthesamegranitemassCoalsarenotmineralsinthegeologicalsense,butagroupofbeddedrocksformedbytheaccumulationofvegetablematterMostcoalseamswereformedovermillionyearsagobythedecompositionofvegetablematterfromthedensetropicalforestswhichcoveredcertainareasoftheearthDuringtheearlyformationofthecoalseams,therottingvegetationformedthickbedsofpeat,anunconsolidatedproductofthedecompositionofvegetation,foundinmarshesandbogsThislaterbecameoverlainwithshales,sandstones,mud,andsilt,andundertheactionoftheincreasingpressureandtemperatureandtime,thepeatbedsbecamealtered,ormetamorphosed,toproducethesedimentaryrockknownascoalThedegreeofalterationisknownastherankofthecoal,thelowestranks(ligniteorbrowncoal)showinglittlealteration,whilethehighestrank(anthracite)isalmostpuregraphite(carbon)Wills'MineralProcessingTechnologyMetallicoreprocessingMetalsTheenormousgrowthofindustrialisationfromtheeighteenthcenturyonwardledtodramaticincreasesintheannualoutputofmostmineralcommodities,particularlymetalsCopperoutputgrewbyafactorofinthetwentiethcenturyalone,andaluminiumbyanastonishingfactorofinthesameperiodFigureshowstheworldproductionofaluminium,copperandzincfortheperiod(datafromUSGS,)AllthesemetalssufferedtoagreaterorlesserextentwhentheOrganisationofPetroleumExportingCountries(OPEC)quadrupledthepriceofoilin,endingthegreatpostwarindustrialboomThesituationworsenedin,whentheIranianrevolutionandthentheIranIraqwarforcedthepriceofoilupfrom$tonearly$abarrel,plungingtheworldintoanotheranddeeperrecession,whileearlyinaglutintheworld'soilsupplycutthepricefrom$abarrelinDecembertobelow$inIraq'sinvasionofKuwaitinpushedthepriceupagain,from$inJulytoapeakof$inOctober,althoughbythenoftheworld'senergywasbeingprovidedbynaturalgasIn,overproductionandtheAsianeconomiccrisisdepressedoilpricestoaslowas$abarrelfromwhereithasclimbedsteadilytoarecordfigureofover$abarrelin,drivenlargelybydemandespeciallyfromtheemergingAsianeconomies,particularlyChinaTheselargefluctuationsinoilpriceshavehadasignificantimpactonmetalliferousoremining,duetotheir,influencebothontheworldeconomyandthusthedemandformetals,anddirectlyontheenergycostsofminingandprocessingIthasbeenestimatedthattheenergycostincopperproductionisaboutofthesellingpriceofthemetal(Dahlstrom,)ThepriceofmetalsisgovernedmainlybysupplyanddemandSupplyincludesbothnewlyminedandrecycledmetal,andrecyclingisnowasignificantcomponentofthelifecycleofsomemetalsaboutofleadsupplycomesfromrecycledsourcesTherehavebeenmanyprophetsofdoomovertheyearspessimisticallypredictingtheimminentexhaustionofmineralsupplies,themostextremeperhapsbeingthenotorious"LimitstoGrowth"reporttotheClubofRomein,whichforecastthatgoldwouldrunoutin,zincin,andoilby(Meadowsetal,)Infactmajoradvancesinproductivityandtechnologythroughoutthetwentiethcenturygreatlyincreasedboththeresourceandthesupplyofnewlyminedmetals,throughgeologicaldiscoveryandreductionsinthecostofproductionThisactuallydrovedownmetalpricesinrealterms,whichreducedtheprofitabilityofminingcompaniesandhadadamagingeffectoneconomiesheavilydependentonmining,particularlythoseinAfricaandSouthAmericaThisinturndrovefurtherimprovementsinproductivityandtechnologyClearlymineralresourcesarefinite,butsupplyanddemandwillgenerallybalanceinsuchFigureWorldproductionofaluminium,copperandzincfortheperiodawaythatifsuppliesdeclineordemandincreases,thepricewillincrease,whichwillmotivatethesearchfornewdeposits,ortechnologytorendermarginaldepositseconomic,orevensubstitutionbyothermaterialsInterestinglygoldisanexception,itspricehavingnotchangedmuchinrealtermssincethesixteenthcentury,duemainlytoitsuseasamonetaryinstrumentandastoreofwealth(Humphreys,)EstimatesofthecrustalabundancesofmetalsaregiveninTable(Taylor,),togetherwiththeactualamountsofsomeofthemostusefulmetals,toadepthofkm(ChiLung,)Theabundanceofmetalsintheoceansisrelatedtosomeextenttothecrustalabundances,sincetheyhavecomefromtheweatheringofthecrustalrocks,butsuperimposeduponthisaretheeffectsofacidrainwatersonmineralleachingprocessesthusthemetalavailabilityfromseawatershowninTable(ChiLung,)doesnotfollowpreciselythatofthecrustalabundanceTheseabedmaybecomeaviablesourceofmineralsinthefutureManganesenoduleshavebeenknownsincethebeginningofthenineteenthcentury(Mukherjeeetal,),andrecentlymineralrichhydrothermalventshavebeendiscoveredandplansarebeingmadetominethem(Scott,)ItcanbeseenfromTablethateightelementsaccountforoveroftheearth'scrustisIntroductionTableAbundanceofmetalintheoceansElementAbundanceElementinseawater(tonnes)Abundanceinseawater(tonnes)MagnesiumSiliconAluminiumIronMolybdenumZincTinUraniumCopperNickelVanadium}TitaniumCobalt}~SilverTungstenChromiumGoldZirconiuml~Platinum<siliconandoxygen,andonlythreeoftheindustriallyimportantmetals(aluminium,iron,andmagnesium)arepresentinamountsaboveAlltheotherusefulmetalsoccurinamountsbelowcopper,forexample,whichisthemostimportantnonferrousmetal,occurringonlytotheextentofItisinterestingtonotethatthesocalledcommonmetals,zincandlead,arelessplentifulthantherareearthmetals(cerium,thorium,etc)Itisimmediatelyapparentthatifthemineralscontainingtheimportantmetalswereuniformlydistributedthroughouttheearth,theywouldbesothinlydispersedthattheireconomicextractionwouldbeimpossibleHowever,theoccurrenceofmineralsinnatureisregulatedbythegeologicalTableAbundanceofmetalintheoceansElementAbundance()Amountinkmofcrust(tonnes)ElementAbundance()Amountinkmofcrust(tonnes)(Oxygen)SiliconAluminiumIronCalciumSodiumMagnesiumPotassiumTitaniumManganeseBariumStrontiumRareearthsZirconiumVanadiumChromiumNickelZincCopperCobaltLeadUraniumTinTungstenMercury•Silver•Gold<xPlatinummetals<•<Wills'MineralProcessingTechnologyconditionsthroughoutthelifeofthemineralAparticularmineralmaybefoundmainlyinassociationwithonerocktype,egcassiteritemainlyassociateswithgraniterocks,ormaybefoundassociatedwithbothigneousandsedimentaryrocks(iethoseproducedbythedepositionofmaterialarisingfromthemechanicalandchemicalweatheringofearlierrocksbywater,ice,andchemicaldecay)Thus,whengraniteisweathered,cassiteritemaybetransportedandredepositedasanalluvialdepositDuetotheactionofthesemanynaturalagencies,mineraldepositsarefrequentlyfoundinsufficientconcentrationstoenablethemetalstobeprofitablyrecoveredItistheseconcentratingagenciesandthedevelopmentofdemandasaresultofresearchanddiscoverywhichconvertamineraldepositintoanoreMostoresaremixturesofextractablemineralsandextraneousrockymaterialdescribedasgangueTheyarefrequentlyclassedaccordingtothenatureofthevaluablemineralThus,innativeoresthemetalispresentintheelementaryformsulphideorescontainthemetalassulphides,andinoxidisedoresthevaluablemineralmaybepresentasoxide,sulphate,silicate,carbonate,orsomehydratedformoftheseComplexoresarethosecontainingprofitableamountsofmorethanonevaluablemineralMetallicmineralsareoftenfoundincertainassociationswithinwhichtheymayoccurasmixturesofawiderangeofparticlesizesorassinglephasesolidsolutionsorcompoundsGalenaandsphalerite,forexample,associatethemselvescommonly,asdocoppersulphidemineralsandsphaleritetoalesserextentPyrite(FeS)isveryoftenassociatedwiththesemineralsOresarealsoclassifiedbythenatureoftheirgangues,suchascalcareousorbasic(limerich)andsiliceousoracidic(silicarich)AnorecanbedescribedasanaccumulationofmineralinsufficientquantitysoastobecapableofeconomicextractionTheminimummetalcontent(grade)requiredforadeposittoqualifyasanorevariesfrommetaltometalManynonferrousorescontain,asmined,aslittleasmetal,andoftenmuchlessGoldmayberecoveredprofitablyinorescontainingonlypartpermillion(ppm)ofthemetal,whereasironorescontaininglessthanaboutmetalareregardedasoflowgradeEverytonneofmaterialinthedeposithasacertaincontainedvaluewhichisdependentonthemetalcontentandcurrentpriceofthecontainedmetalForinstance,atacopperpriceofsandamolybdenumpriceofsadepositcontainingcopperandmolybdenumhasacontainedvalueofmorethansThedepositwillbeeconomictowork,andcanbeclassifiedasanoredepositif:Containedvaluepertonne>(totalprocessingcostslossesothercosts)pertonneAmajorcostismining,andthiscanvaryenormously,fromonlyafewpencepertonneoforetowelloversHightonnageoperationsarecheaperintermsofoperatingcostsbuthavehigherinitialcapitalcostsThesecapitalcostsarepaidoffoveranumberofyears,sothathightonnageoperationscanonlybejustifiedforthetreatmentofdepositslargeenoughtoallowthisSmallorebodiesareworkedonasmallerscale,toreduceoverallcapitalcosts,butcapitalandoperatingcostspertonnearecorrespondinglyhigher(Ottley,)Alluvialminingisthecheapestmethodand,ifonalargescale,canbeusedtomineoresofverylowcontainedvalueduetolowgradeorlowmetalprice,orbothForinstance,inSEAsia,tinorescontainingaslittleasSnareminedbyalluvialmethodsTheseoreshadacontainedvalueoflessthansbutverylowprocessingcostsallowedthemtobeeconomicallyworkedH

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