反式破碎机外文翻译

MineralsVolume14,Issue11,November2001,PagesCOMMINUTIONINANON-CYLINDRICALROLLP.VELLETRI~andD.M.WEEDON~~[Dept.ofMechanical&MaterialsEngineering,UniversityofWesternAustralia,35StirlingHwv,Crawley6009,Australia.E-mailpiero@.au§FacultyofEngineeringandPhysicalSystems,CentralQueenslandUniversity,POBoxGladstone,Qld.4680,Australia(Received3May2001;accepted4SeptemberLowreductionratiosandhighwearratesarethetwocharacteristicsmostcommonlyassociatedwithconventionalrollcrushers.Becauseofthis,rollcrushersarenotoftenconsideredforuseinmineralprocessingcircuits,andmanyoftheiradvantagesarebeinglargelyoverlooked.Thispaperdescribesanovelrollcrusherthathasbeendevelopedinordertoaddresstheseissues.ReferredtoastheNCRC(Non-CylindricalRollCrusher),thenewcrusherincorporatestworollscomprisedofanalternatingarrangementofneandconvexorconcavesurfaces.Theseuniquerollprofilesimprovetheangleofnip,enablingtheNCRCtoachievehigherreductionratiosthanconventionalrollcrushers.Testswithamodelprototypehaveindicatedthat,evenforveryhardores,reductionratiosexceeding10:1canbeattained.Inaddition,sincethecomminutionprocessintheNCRCcombinestheactionsofrollandjawcrushersthereisapossibilitythatthenewprofilesmayleadtoreducedrollwearrates.:Comminution;crushingConventionalrollcrusherssufferfromseveraldisadvantagesthathavelcdtotheirlackofpopularityinmineralprocessingapplications.Inparticular,theirlowreductionratios(typicallylimitedtoabout3:1)andhighwearratesmakethemunattractivewhencomparedtoothertypesofcomminutionequipment,suchasconecrushers.Thereare,however,somecharacteristicsofrollcrushersthatareverydesirablefromamineralprocessingpointofview.Therelativelyconstantoperatinggapinarollcrushergivesgoodcontroloverproductsize.Theuseofspring-loadedrollsmakethesemachinestoleranttouncrushablematerial(suchastrampmetal).Inaddition,rollcrushersworkbydrawingmaterialintothecompressionregionbetweentherollsanddonotrelyongravitationalfeeci~likeconeandjawcrushers.Thisgeneratesacontinuouscrushingcycle,whichyieldshighthroughputratesandalsomakesthecrushercapableofprocessingwetandstickyore.TheNCRCisanovelrollcrusherthathasbeendcvelopedattheUniversityofWesternAustraliainordcrtoaddresssomeoftheproblemsassociatedwithconventionalrollcrushers.Thenewcrusherincorporatestworollscomprisedofanalternatingarrangementofneandconvexor设计巴巴surfaccs.Thcseuniquerollprofilesimprovetheangleofnip,enablingtheNCRCtoachievehigherreductionratiosthanconventionalrollcrushers.Preliminarytestswithamodelprototypehaveindicatedthat,evenforveryhardoics,reductionratiosexceeding10:Icanbeattained(VellelriandWeedon,2000).Theseinitialfindingswereobtainedforsingleparticlefeed.wherethereisnosignificantinctionbetweenparticlesduringcomminution.Thecurrentworkextendstheexistingresultsbvexamininginulti-particlecomminutionintheNCRC.Italsolooksatvariousothcrfactorsthatinfluencctheperli~rmanceoftheNCRCandexplorestheeffectivenessofusingtheNCRCfortheprocessingofmillscats.PRINCIPLEOFOPERATIONTheangleofnipisoneofthemainlectorseffcctingtheperformanceofarollSmallerniparebeneficialsincetheyincreasetl~elikelihoodofparlictesbcinggrabbedandcrushedbylherolls.Foragivenfeedsizeandrollgap,thenipangleinaconventionalrtHlcrusherislimitedbythesizeofthcrolls.TheNCRCattemptsto ethislimitationthroughtheuseofprofiledrolls,whichimprovetheangleofnipatvariouspointsduringonecycle(orrevolution)oftherolls.Inadditiontothenipangle,anumberofotherfactorsincludingvariationmrollgapandmodeofcommmutionwereconsideredwhenselectingIllerollprofiles.ThefinalshapesoftheNCRCrollsareshowninFigureI.Oneoftherollsconsists{sIanalternatingarrangementofneandconvexsurfaces,whiletheotherisformedfromanalternatingarrangementofphmeandconcaveTheshapeoftherollsontheNCRCresultinseveraluniquecharacteristics.Tilemostimportantisthat,lk)ragivenparticlesizeandrollgap,thenipanglegeneratedmtheNCRCwillnotremainconstantastherollsrotate.Therewillbetimeswhenthenipangleismuchlowerthanitwouldbeforthesamesizedrollsandtimeswhenitwillbemuchhighcr.Theactualvariationinnipangleovera60degreerollisillustratedinFigure2,whichalsoshowsthenipanglegeneratedundersimilarconditionsmarollcrusherofcomparablesize.Thesenipangleswerecalculatedfora25ramdiametercircularbetweenrollofapproximay200ramdiametersetataImmminimumgap.Thisexamplecanbeusedtoillustratethepotentialadvantageofusingnon-cylindricalrolls.Inorderforaparticletobegripped,thcangleofnipshouldnormallynotexceed25°.Thus,thecylindricalrollcrusherwouldneverparticle,sincetheactualnipangleremainsconstantatapproximay52°.ThenipanglegeneratedbytheNCRC,however,tidlsbelow25°onceastherollsrotateby(~0degrees.Thismeansthattherollshaveapossibilityofniptheparticlc6timesduringonerollrewHution.PROCEDUREThelaboratoryscaleprototypeoftheNCRC(Figure3)consistsoftworollunits,eachcomprisingamotor,gearboxandprofiledroll.Bothunitsaremountedonlinearbearings,whicheffectivelysupportanytofwhileenablinghorizontalmotion.Onerollunitishorizontallyfixedwhileotherrestrainedviaacompressionspring,whichallowsittoresistavaryingdegreeofhorizontalload.Thepre-loadonthemovablerollcanbeadjusteduptoaumof20kN.Thetwomotorsthatdrivetherollsareelectronicallysynchronisedthroughavariablespeedcontroller,enablingtherollspeedtocontinuouslyvariedupto14rpm(approximay0.14m/ssurfacespeed).Therollshaveacentre-distance~,atzerogapsetting)ofI88mmandawidthof100mm.Bothdriveshaftsareinstrumentedstraingaugestoenabletherolltorquetobemeasured.Additionalsensorsareprovidedtomeasurehorizontalonthestationaryrollandthegapbetweentherolls.ClearglassisfittedtothesidesoftheNCRCtofacilitateviewingofthecrushingzoncduringoperationandalsoallowsthecrushingsequencetobcrecordedusingahigh-speeddigital设计巴巴Testswereperformedonseveraltypesofrocksincludinggranite,diorite,mineralore,millscatsandconcrete.Thegraniteanddioritewereobtainedfromseparatecommercialquarries;theformerhadpre-crushedandsized,whilethelatterwasas-blastedrock.ThefirstoftheoresampleswasSAGmillfeedobtainedfromNormandyMining'sGoldenGroveoperations,whilethemillscatswereobtainedAuroraGold'sMtMurominesiteincentraltan.Themillscatsincludedmetalparticlesofupto18ramdiameterfromwornandbrokengrindingmedia.Theconcreteconsistedofcylindrical(25mmdiameterby25ramhigh)thatwerepreparedinthelaboratoryinaccordancewiththerelevantAustralianStandards.Unconfineduniaxialcompressiontestswereperformedoncoresamplesdiameterby25mmhigh)takenfromanumberoftheores.Theresultsindicatedstrengthrangingfrom60MPaforthepreparedconcreteupto260MPafortheGoldenGroveoreAllofthesampleswereinitiallypassedthrougha37.5mmsievetoremoveanyoversizedundersizedorewasthensampledandsievedtodeterminethefeedsizedistribution.Foreachtrialapproximay2500gofsamplewascrushedintheNCRC.Thissamplesizewaschosenonthebasisstatisticaltests,whichindicatedthatatleast2000gofsampleneededtobecrushedinordertoestimatetheproductP80towithin+0.1ramwith95%confidence.Theproductwascollectedandriffledintotenandastandardwet/drysievingmethodwasthenusedtodeterminetheproductsizedistribution.Foreachtrial,twoofthesub-sampleswereinitiallysieved.Additionalsub-samplesweresievedifwereanysignificantdifferencesintheresultingproductsizeAnumberofcomminutiontestswereconductedusingtheNCRCtodeterminetheeffectsofvariousparametersincludingrollgap,roll,feedsize,andtheeffectofsingleandmulti-particlefeed.Therollspeedwassetatumandwasnotvariedbetweentrialsaspreviousexperimentshadconcludedthattherewaslittleeffectofrollspeedonproductsizedistribution.Itshouldbenotedthattherollgapquotedrefertotheminimumrollgap.Duetothenon-cylindricalshapeoftherolls,theactualrollgapwillvaryupto1.7mmabovetheminimumsetting(ie:arollgapsellingoflmmactuallymeans2.7mmRESULTSFeedmaterialTheperformanceofallcomminutionequipmentisdependentonthetypeofmaterialbeingcrushed.Inthisrespect,theNCRCisnodifferent.SoftermaterialscrushedintheNCRCyieldalowerP80thanmaterials.Figure4showstheproductsizedistributionobtainedwhenseveraldifferentmaterialscrushedundersimilarconditionsintheNCRC.Itisinterestingtonotethatapartfromthepreparedsamples,theP80valuesobtainedfromthevariousmaterialswerefairlyconsistent.TheseresultsreflectthedegreeofcontroloverproductsizedistributionthatcanbeobtainedwiththeNCRC.MultiplefeedparticlesPrevioustrialswiththeNCRCwereconductedusingonlysinglefeedparticleswheretherewaslittleornoinctionbetweenparticles.Althoughveryeffective,thelowthroughputratesassociatedwiththisofcomminutionmakesitunsuitableforpracticalapplications.Thereforeitwasnecessarytodeterminetheeffectthatacontinuousfeedwouldhavetotheresultingproductsizedistribution.Inthesetests,thewascontinuouslydwithfeedtomaintainabedofmateriallevelwiththetopoftheFigureshowstheeffectthatcontinuousfeedtotheNCRChadontheproductsizedistributionfortheOre.TheseresultsseemtoshowaslightincreaseinP80withcontinuous(multi-particle)feed,howevertheshiftissosmallastomakeitstatisticallyinsignificant.Similarly,theproductsizedistributionswouldseemtoindicatealargerproportionoffinesforthecontinuouslyfedtrial,buttheactualdifferenceisSimilartrialswerealsoconductedwiththegranitesamplesusingtwodifferentrollgaps,asshownFigure6.Onceagaintherewaslittlevariationbetweenthesingleandmulti-particletests.Notthedifferencewasevenlesssignificantatthelargerrollgap,wherethedegreeofcomminution(andinctionbetweenparticles)is设计巴巴AllofthesetestswouldseemtoindicatethatcontinuousfeedinghasminimaleffectontheperformanceoftheNCRC.However,itisimportanttorealisethatthefeedparticlesusedinthesetrialswerespreadoveraverysmallsizerange,asevidentbythefeedsizedistributionshowninFigure6(thefeedparticlesintheNormandytrialswereevenmoreuniform).Theunilormityinfeedparticlesizeresultsinalargeamountofspace,whichallow:sforswellingofthebrokenoreinthecrushingchamber,therebylimitingamountofinctionbetweenparticles.True"choke"feedingoftheNCRCwithorehavingawidedistributionofparticlesizes(especiallyinthesmallersizerange)islikelytogeneratemuchlargerinthecrushingzone.SincetheNCRCisnotdesignedtoactasa"'highpressuregrindingroll"anumberofoversizeparticleswouldpassbetweentherollsunderthese设计巴巴RollgapAswithatraditionalrollcrusher,therollgapsettingontheNCRChasadirectinfluenceontheproductsizedistributionandthroughputofthecrusher.Figure7showstheresultingproductsizedistributionandthroughputofthecrusher.Figure7showstheresultingproductsizedistributionobtainedwhentheAuroraGoldore(millscats)wascrushedatthreedifferentrollgaps.PlottingthevaluestakenfromthisgraphagainsttherollgapyieldsthelinearrelationshipshowninFigure8.Asexinedpreviously,theactualrollgapontheNCRCwillvaryoveronerevolution.ThisvariationaccountsforthedifferencebetweenthespecifiedgapsettingandproductPs0obtainedfromthetrials.Figure8alsoshowstheeffectofrollgaponthroughputofthecrusherandgivesanindicationofthecrushingratesthatcanbeobtainedwiththelaboratoryscalemodelRollTheNCRCisdesignedtooperatewithminimalinctionbetweenparticles,suchthatcomminutionisprimarilyachievedbyfractureofparticlesdirectlybetweentherolls.Asaconsequence,therollonlyneedstobclargeenoughto ethecombinedcompressivestrengthsoftheparticlesbetweentherollsurlaces.Iftherollisnotlargeenoughthentheoreparticleswillseparatetherollsallowingparticlestolallthrough.Increasingtherollreducesthetendencyoftherollstoseparateandprovidesbettercontroloverproductsize.However,oncealimitingrollhasbeenreached(whichisdependentonthesizeandtypeofmaterialbeingcrushed)anyfurtherincreaseinrolladdsnothingtotheperformanceoftherollcrusher.ThisisdemonstratedinFigure9,whichshowsthatforgranitefeedof25-3Immsize,arollofapproximay16to18kNisrequiredtocontroltheproductUsinglargerrollhaslittleeffectontheproductsize,althoughthereisarapidincreaseinproductP80iftherollisreducedbek>wthislevel.Asmentionedpreviously,thefeedsizedistributionhasasignificanteffectonthepressuregeneratedinthecrushingchamber.Orethathasafinerfeedsizedistributiontendsto"choke"theNCRCmore,reducingtheeffectivenessofthecrusher.However,aslongasthepressuregeneratedinnotexcessivetheNCRCmaintainsarelativelyconstantoperatinggapirrespectiveofthefeedsize.Theproductsizewill,therefore,alsobcindependentofthefeedsizedistribution.ThisisillustratedinFigure10,showstheresultsoftwocrushingtrialsusingidenticalequipmentsettingsbutwithfeedorehavingdifferentsizedistributions.Inthisexample,theNCRCreducedthecourserorefromanFs0of34mmtoaPs0of3.0mm(reductionratioof11:1),whilethefinerorewasreducedfromanFs0of18mmtoaPsoof3.4mm(reductionratioof5:1).Theseresultssuggestthattheadvantagesofusingprofiledrollsdiminishastheratioofthefeedsizetorollsizeisreduced.Inotherwords,toachievehigherreductionratiosthefeed设计巴巴MillscatsSomegrindingcircuitsemployarecycleorpebblecrusher(suchasaconecrusher)toprocessmaterialwhichbuildsupinamillandwhichthemillfindshardtobreak(millscats).Themillscatsoftenwornorbrokengrindingmedia,whichcanfinditswayintotherecyclecrusher.Atolerancetomaterialisthereforeadesirablecharacteristicforapebblecrushertohave.TheNCRCseemsideallysuitedtosuchanapplication,sinceoneoftherollshastheabilitytoyieldallowingtheuncrushablematerialtopassTheproductsizedistributionsshowninFigure11wereobtainedfromtheprocessingofmillscatsintheNCRC.Identicalequipmentsettingsandfeedsizedistributionswereusedforbothresults,howeveroneofthetrialswasconductedusingfeedoreinwhichthegrindingmediahadbeenremoved.Asexpected,NCRCwasabletoprocessthefeedorecontaininggrindingmediawithout.However,sincerollwasoftenmovinginordertoallowthegrindingmediatopass,anumberofoversizedparticlesabletofallthroughthegapwithoutbeingbroken.Consequently,theproductsizedistributionforthisfeedoreshowsashifttowardsthelargerparticlesizes,andthePs0valueincreasesfrom4ramtoInofthis,theNCRCwasstillabletoachieveareductionratioofalmost设计巴巴WearAlthoughnospecificteslswereconductedtodeterminethewearratesontherollsoftheNCRC,anumberofthecrushingtrialswererecordedusingahigh-speedcamerainordertotryandunderstandcomminutionmechanism.ByobservingparticlesbeingbrokenbetweentherollsitispossibletoportionsoftherollswhicharelikelytosufferfromhighwearandtomakesomesubjectiveconclusionsastotheeffectthatthiswearwillhaveontheperlbrmanceoftheNCRC.Notsurprisingly,theregionshowsupasbeingtheprimecandidateforhighwcaristhetransitionbetweentheflatandconcaveWhatissurprisingisthatthisedgedoesnotyasignificantroleingeneratingtheimprovednipTheperformanceoftheNCRCshouldnotbeadverselyeffcctedbyweartothisedgebecauseitisthetransitionbetweenthefiatandconvexsurfaces(ontheopposingroll)thatresultsinthereducedThevide()alsoshowsthattorpartofeachcycleparticlesarecomminutedbetweentheflatsurfacesoftherolls,inmuchthesamewayastheywouldbeinajawcrusher.ThiscanbeclearlyseenonthesequenceofimagesinFigure12.Thewearontherollsduringthispartofthecycleislikely'tobeminimalsincethereislittleornorelativemotionbetweentheparticlesandthesurfaceofthe设计巴巴Theresultspresentedhavedemonstratedsomeofthefactorseffectingthecomminutionofparticlesinanon-cylindricalrollcrusher.Thehighreductionratiosobtainedfromearlysingleparticletestscanstillbeachievedwithcontinuousmulti-particlefeed.However,aswithatraditionalrollcrusher,theNCRCsusceptibletochokefeedingandmustbestarvationfedinordertooperateeffectively.ThetypeofmaterialhaslittleeffectontheperformanceoftheNCRCand,althoughnottested,itisanticipatedthatthemoisturecontentofthefeedorewillalsonotadverselyaffectthecrusher'sper[Brmance.ResultsfromthemillscattrialsareparticularlypromisingbecausetheydemonstratethattheNCRCisabletoprocesscontainingmetalfromworngrindingmedia.Theabovefactors,incombinationwiththeflakynatureoftheproductgenerated,indicatethattheNCRCwouldmakeanexcellentrecycleorpebblecrusher.Italsobeinterestingtodeterminewhetherthereisanydifferenceintheballmillenergyrequiredto productobtainedfromtheNCRCcomparedthatobtainedfromaconecrusher.PresentedatComminution'01,Brisbane,Australia,March2001Copyright©2001PublishedbyElsevier.为这点在矿石处理流程的应用中很少考虑到它们并且忽略了很多它们的优点。本文描述了一个已被发展起来的新颖的对辊破碎机旨在提出这些论点。作NCRC,这种新式破碎机结合了两个辊筒它们由一个交替布置的平面和一个凸的或者凹的表面组成。这种独特的辊筒外形提高了啮合角使NCRC可以达到比传统辊式破碎机更高的破碎比。用一个模型样机做的试验表明即使对于非常硬的矿石破碎比任可以超过10。另外既然在NCRC的破碎处理中结合了辊式和颚式破碎机的作用那就有一种可能那种新的轮廓会带来辊子磨损率的降低。欢迎。尤其是当与其它的一些破碎机比起来诸如圆锥破碎机等比一般局限在3以内和高的磨损率使它们没有。然而从矿石处理—点来 辊筒破碎机有一些非常可取的特 辊筒破碎机的相对稳定的操作设计巴巴度可以很好控制产物粒度。弹簧承重的辊子的使用使这料诸如夹杂金属等。另外辊筒破碎机是这样工作的将物料牵引至辊子之周期避免了高通过率同时也使破碎机可处理潮湿的和胶粘的物料。NCRC是一种新颖的破碎机发明于澳大利亚西部大学为得是提出一些与传统辊筒破碎机相联系的一些问题。新的破碎机结合了两个辊子由间隔布置的平NCRC可达到比传统辊筒破碎机更高的破碎比。用一个模型样机的初步试验已表明即使非常硬的物料超过10的破碎比也可以实现。这些初期的发现是通过单一颗粒进NCRC中用NCRC特性和NCRC在选矿处理中使用效率。啮合角是影响辊筒破碎机性能的重要因一。小的啮合角是有利的因它们增大了物块被辊筒抓住的可能性。对于一个给定的入料粒度和辊隙传统的辊筒破碎机的啮合角受限于辊筒的尺寸。NCRC试图通过有特殊轮廓的辊筒克服这种限制这种轮廓提高了辊筒在一转中变化点的啮合角。至于啮合角在选择辊面时很多其他的因素包括变化的辊隙破碎的方式都考虑了。最终NCRC1所示。其中一个辊子由间隔布置的平面和凸面组成而另一个是NCRC辊筒的形状导致了几个独特的特点其中最重要的就是在辊筒转动时对于一个给定物 NCRC所产生的啮合角将不再保持稳定。时而啮合角比相同尺寸的圆柱辊筒低很多时而高很多。辊子转动中啮合角的实际变化60度2所示2也表示了相同情况下可相比尺寸的圆柱辊筒25毫米的圆形物块放在辊2001毫米的辊筒间计算出来的。这个例子可以用来描述使用非圆柱辊筒的潜在优点。为了抓住物块25度。因此52度。然而在辊筒转过60度时NCRC25度以下。这意味着辊筒每转过一转非圆柱辊筒破碎机可能有6次物块。NCRC的模型由两个辊筒部件组成每一个由发动机、齿轮箱和有形辊筒组成。两个部件都安置性轴承上其有效支持任何垂直部件的力同时保证其水平运动。一个辊筒部件水平固定而另一个通过压缩弹簧限制压缩弹簧14每秒大概0.14米每秒的线速度。辊筒有一个188毫米的中心 100毫米宽两个驱动轴都装有应变 用以测量辊筒扭矩。附加的传感器用以测量固定辊设计巴巴的水平力和辊隙。NCRC的边上装有透明玻璃以便于在运行是观察破碎区域同花岗岩和混凝土各取自商业性的采石场前者先破碎、成形而后者是的岩石。第一种矿石样品是SAG采石场进料取于诺曼底煤矿的GGO 于KAGMM煤矿。采石场弃石含有直径直至18毫米的金属颗粒它们来自于经反复磨削和破碎的介质。混凝土由圆柱体样品直径25毫米、高25毫米组成直径25毫米、高25毫米 取于大量的矿石。结果表明