破碎机外文翻译Word下载.docx
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破碎机外文翻译Word下载.docx
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19,
Gladstone,Qld.4680,Australia(Received3May2001;
accepted4September2001)
ABSTRACT
Lowreductionratiosandhighwearratesarethetwocharacteristicsmostcommonlyassociatedwithconventionalrollcrushers.Becauseofthis,rollcrushersarenotoftenconsideredforuseinmineralprocessingcircuits,andmanyoftheiradvantagesarebeinglargelyoverlooked.Thispaperdescribesanovelrollcrusherthathasbeendevelopedinordertoaddresstheseissues.ReferredtoastheNCRC(Non-CylindricalRollCrusher),thenewcrusherincorporatestworollscomprisedofanalternatingarrangementofplaneandconvexorconcavesurfaces.Theseuniquerollprofilesimprovetheangleofnip,enablingtheNCRCtoachievehigherreductionratiosthanconventionalrollcrushers.Testswithamodelprototypehaveindicatedthat,evenforveryhardores,reductionratiosexceeding10:
1canbeattained.Inaddition,sincethecomminutionprocessintheNCRCcombinestheactionsofrollandjawcrushersthereisapossibilitythatthenewprofilesmayleadtoreducedrollwearrates.
Keywords:
Comminution;
crushing
INTRODUCTION
Conventionalrollcrusherssufferfromseveraldisadvantagesthathavelcdtotheirlackofpopularityinmineralprocessingapplications.Inparticular,theirlowreductionratios(typicallylimitedtoabout3:
1)andhighwearratesmakethemunattractivewhencomparedtoothertypesofcomminutionequipment,suchasconecrushers.Thereare,however,somecharacteristicsofrollcrushersthatareverydesirablefromamineralprocessingpointofview.Therelativelyconstantoperatinggapinarollcrushergivesgoodcontroloverproductsize.Theuseofspring-loaded
rollsmakethesemachinestoleranttouncrushablematerial(suchastrampmetal).Inaddition,rollcrushersworkbydrawingmaterialintothecompressionregionbetweentherollsanddonotrelyongravitationalfeeci~likeconeandjawcrushers.Thisgeneratesacontinuouscrushingcycle,whichyieldshighthroughputratesandalsomakesthecrushercapableofprocessingwetandstickyore.TheNCRCisanovelrollcrusherthathasbeendcvelopedattheUniversityofWesternAustraliainordcrtoaddresssomeoftheproblemsassociatedwithconventionalrollcrushers.Thenewcrusherincorporatestworollscomprisedofanalternatingarrangementofplaneandconvexorconcave
设计巴巴工作室surfaccs.Thcseuniquerollprofilesimprovetheangleofnip,enablingtheNCRCto
achievehigherreductionratiosthanconventionalrollcrushers.Preliminarytestswith
amodelprototypehaveindicatedthat,evenforveryhardoics,
reductionratiosexceeding10:
Icanbeattained(VellelriandWeedon,2000).These
initialfindingswereobtainedforsingleparticlefeed.wherethereisnosignificant
interactionbetweenparticlesduringcomminution.Thecurrentworkextendsthe
existingresultsbvexamininginulti-particlecomminutionintheNCRC.Italsolooksat
variousothcrfactorsthatinfluencctheperli~rmanceoftheNCRCandexplores
theeffectivenessofusingtheNCRCfortheprocessingofmillscats.
PRINCIPLEOFOPERATION
Theangleofnipisoneofthemainlectorseffcctingtheperformanceofarollcrusher.
Smallernipangles
arebeneficialsincetheyincreasetl~elikelihoodofparlictesbcinggrabbedand
crushedbylherolls.Fora
givenfeedsizeandrollgap,thenipangleinaconventionalrtHlcrusherislimitedby
thesizeofthcrolls.
TheNCRCattemptstoovercomethislimitationthroughtheuseofprofiledrolls,
whichimprovetheangle
ofnipatvariouspointsduringonecycle(orrevolution)oftherolls.Inadditiontothe
nipangle,anumber
ofotherfactorsincludingvariationmrollgapandmodeofcommmutionwere
consideredwhenselecting
Illerollprofiles.ThefinalshapesoftheNCRCrollsareshowninFigureI.Oneofthe
rollsconsists{sIan
alternatingarrangementofplaneandconvexsurfaces,whiletheotherisformedfrom
analternating
arrangementofphmeandconcavesurlaccs.
TheshapeoftherollsontheNCRCresultinseveraluniquecharacteristics.Tilemostimportantisthat,lk)r
agivenparticlesizeandrollgap,thenipanglegeneratedmtheNCRCwillnotremainconstantastherolls
设计巴巴工作室
rotate.Therewillbetimeswhenthenipangleismuchlowerthanitwouldbeforthesamesizedcylindrical
rollsandtimeswhenitwillbemuchhighcr.Theactualvariationinnipangleovera60degreerollrotation
isillustratedinFigure2,whichalsoshowsthenipanglegeneratedundersimilarconditionsmacylindrical
rollcrusherofcomparablesize.Thesenipangleswerecalculatedfora25ramdiametercircularparticle
betweenrollofapproximately200ramdiametersetataImmminimumgap.Thisexamplecanbeusedtoillustratethepotentialadvantageofusingnon-cylindricalrolls.Inorderforaparticletobegripped,thc
angleofnipshouldnormallynotexceed25°
.Thus,thecylindricalrollcrusherwouldnevernipthis
particle,sincetheactualnipangleremainsconstantatapproximately52°
.Thenipanglegeneratedbythe
NCRC,however,tidlsbelow25°
onceastherollsrotateby(~0degrees.Thismeansthatthenon-cylindrical
rollshaveapossibilityofnippingtheparticlc6timesduringonerollrewHution.EXPERIMENTALPROCEDUREThelaboratoryscaleprototypeoftheNCRC(Figure3)consistsoftworollunits,eachcomprisingamotor,
gearboxandprofiledroll.Bothunitsaremountedonlinearbearings,whicheffectivelysupportanyvertical
componcntofforcewhileenablinghorizontalmotion.Onerollunitishorizontallyfixedwhiletheotheris
restrainedviaacompressionspring,whichallowsittoresistavaryingdegreeofhorizontalload.Thepre-loadonthemovablerollcanbeadjusteduptoamaximumof20kN.Thetwomotorsthatdrivethe
rollsareelectronicallysynchronisedthroughavariablespeedcontroller,enablingtherollspeedtobe
continuouslyvariedupto14rpm(approximately0.14m/ssurfacespeed).Therollshaveacentre-to-centre
distance~,atzerogapsetting)ofI88mmandawidthof100mm.Bothdriveshaftsareinstrumentedwith
straingaugestoenabletherolltorquetobemeasured.Additionalsensorsareprovidedtomeasurethe
horizontalforceonthestationaryrollandthegapbetweentherolls.Clearglassisfittedtothesidesofthe
NCRCtofacilitateviewingofthecrushingzoncduringoperationandalsoallowsthecrushingsequenceto
bcrecordedusingahigh-speeddigitalcamera.
设计巴巴工作室Testswereperformedonseveraltypesofrocksincludinggranite,diorite,mineralore,millscatsand
concrete.Thegraniteanddioritewereobtainedfromseparatecommercialquarries;
theformerhadbeen
pre-crushedandsized,whilethelatterwasas-blastedrock.ThefirstoftheoresampleswasSAGmillfeed
obtainedfromNormandyMining'
sGoldenGroveoperations,whilethemillscatswereobtainedfrom
AuroraGold'
sMtMurominesiteincentralKalimantan.Themillscatsincludedmetalparticlesofupto
18ramdiameterfromwornandbrokengrindingmedia.Theconcreteconsistedofcylindricalsamples
(25mmdiameterby25ramhigh)thatwerepreparedinthelaboratoryinaccordancewiththerelevant
AustralianStandards.Unconfineduniaxialcompressiontestswereperformedoncoresamples(25mm
diameterby25mmhigh)takenfromanumberoftheores.Theresultsindicatedstrengthrangingfrom60
MPaforthepreparedconcreteupto260MPafortheGoldenGroveoresamples.
Allofthesampleswereinitiallypassedthrougha37.5mmsievetoremoveanyoversizedparticles.The
undersizedorewasthensampledandsievedtodeterminethefeedsizedistribution.Foreachtrial
approximately2500gofsamplewascrushedintheNCRC.Thissamplesizewaschosenonthebasisof
statisticaltests,whichindicatedthatatleast2000gofsampleneededtobecrushedinordertoestimatethe
productP80towithin+0.1ramwith95%confidence.Theproductwascollectedandriffledintotensubsamples,
andastandardwet/drysievingmethodwasthenusedtodeterminetheproductsizedistribution.
Foreachtrial,twoofthesub-sampleswereinitiallysieved.Additionalsub-samplesweresievedifthere
wereanysignificantdifferencesintheresultingproductsizedistributions.
AnumberofcomminutiontestswereconductedusingtheNCRCtodeterminetheeffectsofvarious
parametersincludingrollgap,rollforce,feedsize,andtheeffectofsingleandmulti-particlefeed.Therollspeedwassetatmaximumandwasnotvariedbetweentrialsaspreviousexperimentshadconcludedthat
therewaslittleeffectofrollspeedonproductsizedistribution.Itshouldbenotedthattherollgapsettings
quotedrefertotheminimumrollgap.Duetothenon-cylindricalshapeoftherolls,theactualrollgapwill
varyupto1.7mmabovetheminimumsetting(ie:
arollgapsellingoflmmactuallymeans1-2.7mmroll
gap).
RESULTSFeedmaterialTheperformanceofallcomminutionequipmentisdependentonthetypeofmaterialbeingcrushed.Inthis
respect,theNCRCisnodifferent.SoftermaterialscrushedintheNCRCyieldalowerP80thanharder
materials.Figure4showstheproductsizedistributionobtainedwhenseveraldifferentmaterialswere
crushedundersimilarconditionsintheNCRC.Itisinterestingtonotethatapar
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