1、ABSTRACT1.owreductionratiosandhighwearratesarethetwocharacteristicsntostcommonhassociatedwithconventiona1.ro1.1.crushers.Becauseofthis,ro1.1.CrushersarenotoftenconsideredJoruseinminera1.processingcircuits,attdmanyoftheiradvantagesarebeing1.arge1.yover1.ooked.Thispaperdescribesanove1.ro1.1.crushertha
2、thasbeendeve1.opediptordertoaddresstheseissues.Re1.brredtoastheNCRC(Non-Cy1.indrica1.Ro1.1.Crusher),thenewcrusherincorporatestworo1.1.scomprisedqfana1.ternatingarrangementofp1.atteattdconvexorconcavesuwes.Theseuniquero1.1.prqfi1.esimprovetheang1.eqfnip,enab1.ingtheNCRCtoachievehigherreductionratiost
3、hanconventiona1.ro1.1.crushers.Testswithamode1.prototypehaveindicatedthareve1.1.fi)rveryhardores,reductionratiosexceeding10:1canbeattained.Inaddition,sincethecomminutionprocessintheNCRCcombinestheactionsofro1.1.arMjawcrushersthereisapossibi1.iOthatthenewprofi1.esmay1.eadtoreducedro1.1.wearrates.2001
4、E1.sevierScience1.td.A1.1.rightsreserved.Keywords:crushingINTRODUCTIONConventiona1.ro1.1.crusherssufferfromsevera1.disadvantagesthathave1.edtotheir1.ackofpopu1.arityinminera1.processingapp1.ications.Inparticu1.ar,their1.owreductionratios(typica1.1.y1.imitedtoabout3:1)andhighwearratesmakethemunattrac
5、tivewhencomparedtoothertypesofcomminutionequipment,suchasconecrushers.Thereare,however,somecharacteristicsofro1.1.crushersthatareverydesirab1.efromaminera1.processingpointofview.There1.ative1.yconstantoperatinggapinaro1.1.crushergivesgoodcontro1.overproductsize.Theuseofspring-1.oadedro1.1.smakethese
6、machinesto1.eranttoUncrushab1.emateria1.(suchastrampmeta1.).Inaddition,ro1.1.crushersworkbydrawingmateria1.intothecompressionregionbetweenthero1.1.sanddonotre1.yongravitationa1.feeci-1.ikeconeandjawcrushers.Thisgeneratesacontinuouscrushingcyc1.e,whichyie1.dshighthroughputratesanda1.somakesthecrusher
7、capab1.eofprocessingwetandstickyore.TheNCRCisanove1.ro1.1.crusherthathasbeendeve1.opedattheUniversityofWesternAustra1.iainordertoaddresssomeoftheprob1.emsassociatedwithconventiona1.ro1.1.crushers.Thenewcrusherincorporatestworo1.1.scomprisedofana1.ternatingarrangementofp1.aneandconvexorconcavesurface
8、s.Theseuniquero1.1.profi1.esimprovetheang1.eofnip,enab1.ingtheNCRCtoachievehigherreductionratiosthanconventiona1.ro1.1.crushers.Pre1.iminarytestswithamode1.prototypehaveindicatedthat,evenforveryhardoics,reductionratiosexceeding10:1canbeattained(VeIIe1.riandWeedon,2000).Theseinitia1.findingswereobtai
9、nedforsing1.epartic1.efeed,wherethereisnosignificantinteractionbetweenpartic1.esduringcomminution.Thecurrentworkextendstheexistingresu1.tsbvexamininginu1.ti-partic1.ecomminutionintheNCRC.Ita1.so1.ooksatvariousotherfactorsthatinf1.uencetheper1.i-manceoftheNCRCandexp1.orestheeffectivenessofusingtheNCR
10、Cfortheprocessingofmi1.1.scats.PRINCIP1.EOFOPERATIONTheang1.eofnipisoneofthemain1.ectorseffectingtheperformanceofaro1.1.crusher.Sma1.1.ernipang1.esarebeneficia1.sincetheyincreaset1.e1.ike1.ihoodofpar1.ictesbeinggrabbedandcrushedbyIhero1.1.s.Foragivenfeedsizeandro1.1.gap,thenipang1.einaconventiona1.r
11、tH1.crusheris1.imitedbythesizeofthero1.1.s.TheNCRCattemptstoovercomethis1.imitationthroughtheuseofprofi1.edro1.1.s,whichimprovetheang1.eofnipatvariouspointsduringonecyc1.e(orrevo1.ution)ofthero1.1.s.Inadditiontothenipang1.e,anumberofotherfactorsinc1.udingvariationmro1.1.gapandmodeofCommmutionwerecon
12、sideredwhense1.ectingI1.1.ero1.1.profi1.es.Thefina1.shapesoftheNCRCro1.1.sareshowninFigureI.Oneofthero1.1.sconsistsisana1.ternatingarrangementofp1.aneandconvexsurfaces,whi1.etheotherisformedfromana1.ternatingarrangementofphmeandconcavesur1.accs.Theshapeofthero1.1.sontheNCRCresu1.tinsevera1.uniquecha
13、racteristics.Ti1.emostimportantisthat,1.k)ragivenpartic1.esizeandro1.1.gap,thenipang1.egeneratedmtheNCRCwi1.1.notremainconstantasthero1.1.srotate.Therewi1.1.betimeswhenthenipang1.eismuch1.owerthanitwou1.dbeforthesamesizedcy1.indrica1.ro1.1.sandtimeswhenitwi1.1.bemuchhigher.Theactua1.variationinnipan
14、g1.eovera60degreero1.1.rotationisi1.1.ustratedinFigure2,whicha1.soshowsthenipang1.egeneratedundersimi1.arconditionsmacy1.indrica1.ro1.1.crusherofcomparab1.esize.Thesenipang1.eswereca1.cu1.atedfora25ramdiametercircu1.arpartic1.ebetweenro1.1.ofapproximate1.y200ramdiametersetataImmminimumgap.Thisexamp1
15、ecanbeusedtoi1.1.ustratethepotentia1.advantageofusingnon-cy1.indrica1.ro1.1.s.Inorderforapartic1.etobegripped,theang1.eofnipshou1.dnorma1.1.ynotexceed25o.Thus,thecy1.indrica1.ro1.1.crusherwou1.dnevernipthispartic1.e,sincetheactua1.nipang1.eremainsconstantatapproximate1.y52o.Thenipang1.egeneratedbyt
16、heNCRC,however,tid1.sbe1.ow25oonceasthero1.1.srotateby(0degrees.Thismeansthatthenon-cy1.indrica1.ro1.1.shaveapossibi1.ityofnippingthepartic1.e6timesduringonero1.1.rewHution.EXPERIMENTA1.PROCEDUREThe1.aboratorysca1.eprototypeoftheNCRC(Figure3)consistsoftworo1.1.units,eachcomprisingamotor,gearboxandpr
17、ofi1.edro1.1.Bothunitsaremountedon1.inearbearings,ponentofforcewhi1.eenab1.inghorizonta1.motion.Onero1.1.unitishorizonta1.1.yfixedwhi1.etheotherisrestrainedviaacompressionspring,whicha1.1.owsittoresistavaryingdegreeofhorizonta1.1.oad.Thepre-1.oadonthemovab1.ero1.1.canbeadjusteduptoamaximumof20kN.The
18、twomotorsthatdrivethero1.1.saree1.ectronica1.1.ysynchronisedthroughavariab1.espeedcontro1.1.er,enab1.ingthero1.1.speedtobecontinuous1.yvariedupto14rpm(approximate1.y0.14m/ssurfacespeed).Thero1.1.shaveacentre-to-centredistanceatzerogapsetting)ofI88mmandawidthof100mm.Bothdriveshaftsareinstrumentedwith
19、straingaugestoenab1.ethero1.1.torquetobemeasured.Additiona1.sensorsareprovidedtomeasurethehorizonta1.forceonthestationaryro1.1.andthegapbetweenthero1.1.s.C1.earg1.assisfittedtothesidesoftheNCRCtofaci1.itateviewingofthecrushingzoneduringoperationanda1.soa1.1.owsthecrushingsequencetoberecordedusingahi
20、gh-speeddigita1.camera.Testswereperformedonsevera1.typesofrocksinc1.udinggranite,diorite,minera1.ore,mi1.1.scatsandconcrete.Thegraniteanddioritewereobtainedfromseparatecommercia1.quarries;theformerhadbeenpre-crushedandsized,whi1.ethe1.atterwasas-b1.astedrock.Thefirstoftheoresamp1.eswasSAGmi1.1.feedo
21、btainedfromNormandyMiningsGo1.denGroveoperations,whi1.ethemi1.1.scatswereobtainedfromAuroraGo1.dsMtMurominesiteincentra1.Ka1.imantan.Themi1.1.scatsinc1.udedmeta1.partic1.esofupto18ramdiameterfromwornandbrokengrindingmedia.Theconcreteconsistedofcy1.indrica1.samp1.es(25mmdiameterby25ramhigh)thatwerepr
22、eparedinthe1.aboratoryinaccordancewiththere1.evantAustra1.ianStandards.Upressiontestswereperformedoncoresamp1.es(25mmdiameterby25mmhigh)takenfromanumberoftheores.Theresu1.tsindicatedstrengthrangingfrom60MPaforthepreparedconcreteupto260MPafortheGo1.denGroveoresamp1.es.A1.1.ofthesamp1.eswereinitia1.1.
23、ypassedthrougha37.5mmsievetoremoveanyoversizedpartic1.es.Theundersizedorewasthensamp1.edandsievedtodeterminethefeedsizedistribution.Foreachtria1.approximate1.y2500gofsamp1.ewascrushedintheNCRC.Thissamp1.esizewaschosenonthebasisofstatistica1.tests,whichindicatedthatat1.east2000gofsamp1.eneededtobecru
24、shedinordertoestimatetheproductP80towithin+0.1ramwith95%confidence.Theproductwasco1.1.ectedandriff1.edintotensubsamp1.es,andastandardwet/drysievingmethodwasthenusedtodeterminetheproductsizedistribution.Foreachtria1.,twoofthesub-samp1.eswereinitia1.1.ysieved.Additiona1.sub-samp1.esweresievediftherewe
25、reanysignificantdifferencesintheresu1.tingproductsizedistributions.AnumberofcomminutiontestswereconductedusingtheNCRCtodeterminetheeffectsofvariousparametersinc1.udingro1.1.gap,ro1.1.force,feedsize,andtheeffectofsing1.eandmu1.ti-partic1.efeed.Thero1.1.speedwassetatmaximumandwasnotvariedbetweentria1.
26、saspreviousexperimentshadconc1.udedthattherewas1.itt1.eeffectofro1.1.speedonproductsizedistribution.Itshou1.dbenotedthatthero1.1.gapsettingsquotedrefertotheminimumro1.1.gap.Duetothenon-cy1.indrica1.shapeofthero1.1.s,theactua1.ro1.1.gapwi1.1.varyupto1.7mmabovetheminimumsetting(ie:aro1.1.gapse1.1.ingo
27、f1mmactua1.1.ymeans1-2.7mmro1.1.gap).RESU1.TSFeedmateria1.Tminutionequipmentisdependentonthetypeofmateria1.beingcrushed.Inthisrespect,theNCRCisnodifferent.Softermateria1.scrushedintheNCRCyie1.da1.owerP80thanhardermateria1.s.Figure4showstheproductsizedistributionobtainedwhensevera1.differentmateria1.
28、swerecrushedundersimi1.arconditionsintheNCRC.Itisinterestingtonotethatapartfromthepreparedconcretesamp1.es,theP80va1.uesobtainedfromthevariousmateria1.swerefair1.yconsistent.Theseresu1.tsref1.ectthedegreeofcontro1.overproductsizedistributionthatcanbeobtainedwiththeNCRC.Mu1.tip1.efeedpartic1.esPrevio
29、ustria1.swiththeNCRCwereconductedusingon1.ysing1.efeedpartic1.eswheretherewas1.itt1.eornointeractionbetweenpartic1.es.A1.thoughveryeffective,the1.owthroughputratesassociatedwiththismodeofcomminutionmakesitunsuitab1.eforpractica1.app1.ications.Thereforeitwasnecessarytodeterminetheeffectthatacontinuou
30、sfeedwou1.dhavetotheresu1.tingproductsizedistribution.Inthesetests,theNCRCwascontinuous1.ysupp1.iedwithfeedtomaintainabedofmateria1.1.eve1.withthetopofthero1.1.s.Figure5showstheeffectthatcontinuousfeedtotheNCRChadontheproductsizedistributionfortheNormandyOre.Theseresu1.tsseemtoshowas1.ightincreasein
31、P80withcontinuous(mu1.ti-partic1.e)feed,howevertheshiftissosma1.1.astomakeitstatistica1.1.yinsignificant.Simi1.ar1.y,theproductsizedistributionswou1.dseemtoindicatea1.argerproportionoffinesforthecontinuous1.yfedtria1.,buttheactua1.differenceisneg1.igib1.e.Simi1.artria1.swerea1.soconductedwiththegran
32、itesamp1.esusingtwodifferentro1.1.gaps,asshowninFigure6.Onceagaintherewas1.itt1.evariationbetweenthesing1.eandmu1.ti-partic1.etests.Notsurprising1.y,thedifferencewaseven1.esssignificantatthe1.argerro1.1.gap,wherethedegreeofcomminution(andhenceinteractionbetweenpartic1.es)issma1.1.er.A1.1.ofthesetest
33、swou1.dseemtoindicatethatcontinuousfeedinghasminima1.effectontheperformanceoftheNCRC.However,itisimportanttorea1.isethatthefeedpartic1.esusedinthesetria1.swerespreadoveraverysma1.1.sizerange,asevidentbythefeedsizedistributionshowninFigure6(thefeedpartic1.esintheNormandytria1.swereevenmoreuniform).Th
34、eUni1.ormityinfeedpartic1.esizeresu1.tsina1.argeamountoffreespace,whicha1.1.ow:sforswe1.1.ingofthebrokenoreinthecrushingchamber,thereby1.imitingtheamountofinteractionbetweenpartic1.es.TruechokefeedingoftheNCRCwithorehavingawidedistributionofpartic1.esizes(especia1.1.yinthesma1.1.ersizerange)is1.ike1
35、ytogeneratemuch1.argerpressuresinthecrushingzone.SincetheNCRCisnotdesignedtoactasahighpressuregrindingro1.1.a1.argernumberofoversizepartic1.eswou1.dpassbetweenthero1.1.sunderthesecircumstances.Ro1.1.gapAswithatraditiona1.ro1.1.crusher,thero1.1.gapsettingontheNCRChasadirectinf1.uenceontheproductsize
36、distributionandthroughputofthecrusher.Figure7showstheresu1.tingproductsizedistributionobtainedwhentheAuroraGo1.dore(mi1.1.scats)wascrushedatthreedifferentro1.1.gaps.P1.ottingthePSOva1.uestakenfromthisgraphagainstthero1.1.gapyie1.dsthe1.inearre1.ationshipshowninFigure8.Asexp1.ainedprevious1.y,theactu
37、a1.ro1.1.gapontheNCRCwi1.1.varyoveronerevo1.ution.ThisvariationaccountsforthedifferencebetweenthespecifiedgapsettingandproductPsOobtainedfromthecrushingtria1.s.Figure8a1.soshowstheeffectofro1.1.gaponthroughputofthecrusherandgivesanindicationofthecrushingratesthatcanbeobtainedwiththe1.aboratorysca1.e
38、mode1.NCRC.Ro1.1.forceTheNCRCisdesignedtooperatewithminima1.interactionbetweenpartic1.es,suchthatcomminutionisprimari1.yachievedbyfractureofpartic1.esdirect1.ybetweenthero1.1.s.Asaconsequence,thero1.1.forceon1.yneedstobe1.argeenoughtoovercomethecombinedcompressivestrengthsofthepartic1.esbetweenthero
39、1.1.sur1.aces.Ifthero1.1.forceisnot1.argeenoughthentheorepartic1.eswi1.1.separatethero1.1.sa1.1.owingoversizedpartic1.estoIa1.1.through.Increasingthero1.1.forcereducesthetendencyofthero1.1.stoseparateandthereforeprovidesbettercontro1.overproductsize.However,oncea1.imitingro1.1.forcehasbeenreached(wh
40、ichisdependentonthesizeandtypeofmateria1.beingcrushed)anyfurtherincreaseinro1.1.forceaddsnothingtotheperformanceofthero1.1.crusher.ThisisdemonstratedinFigure9,whichshowsthatforgranitefeedof25-3Immsize,aro1.1.forceofapproximate1.y16to18kNisrequiredtocontro1.theproductsize.Usinga1.argerro1.1.forcehas1
41、itt1.eeffectontheproductsize,a1.thoughthereisarapidincreaseinproductP80ifthero1.1.forceisreducedbekwthis1.eve1.Asmentionedprevious1.y,thefeedsizedistributionhasasignificanteffectonthepressuregeneratedinthecrushingchamber.OrethathasafinerfeedsizedistributiontendstochoketheNCRCmore,reducingtheeffecti
42、venessofthecrusher.However5as1.ongasthepressuregeneratedinnotexcessivetheNCRCmaintainsare1.ative1.yconstantoperatinggapirrespectiveofthefeedsize.Theproductsizedistributionwi1.1.,therefore,a1.sobeindependentofthefeedsizedistribution.Thisisi1.1.ustratedinFigure10,whichshowstheresu1.tsoftwocrushingtria
43、1.susingidentica1.equipmentsettingsbutwithfeedorehavingdifferentsizedistributions.Inthisexamp1.e,theNCRCreducedthecourserorefromanFsOof34mmtoaPsOof3.0mm(reductionratioof11:1),whi1.ethefinerorewasreducedfromanFsOof18mmtoaPsoof3.4mm(reductionratioof5:1).Theseresu1.tssuggestthattheadvantagesofusingprof
44、i1.edro1.1.sdiminishastheratioofthefeedsizetoro1.1.sizeisreduced.Inotherwords,toachievehigherreductionratiosthefeedpartic1.esmustbe1.argeenoughtotakeadvantageoftheimprovednipang1.esgeneratedintheNCRC.Mi1.1.scatsSomegrindingcircuitsemp1.oyarecyc1.eorpebb1.ecrusher(suchasaconecrusher)toprocessmateria1
45、whichbui1.dsupinami1.1.andwhichthemi1.1.findshardtobreak(mi1.1.scats).Themi1.1.scatsoftencontainwornorbrokengrindingmedia,whichcanfinditswayintotherecyc1.ecrusher.Ato1.erancetoUncrushab1.emateria1.isthereforeadesirab1.echaracteristicforapebb1.ecrushertohave.TheNCRCseemsidea1.1.ysuitedtosuchanapp1.i
46、cation,sinceoneofthero1.1.shastheabi1.itytoyie1.da1.1.owingtheUncrushab1.emateria1.topassthrough.TheproductsizedistributionsshowninFigure11wereobtainedfromtheprocessingofmi1.1.scatsintheNCRC.Identica1.equipmentsettingsandfeedsizedistributionswereusedforbothresu1.ts,howeveroneofthetria1.swasconducted
47、usingfeedoreinwhichthegrindingmediahadbeenremoved.Asexpected,theNCRCwasab1.etoprocessthefeedorecontaininggrindingmediawithoutincident.However5sinceonero1.1.wasoftenmovinginordertoa1.1.owthegrindingmediatopass,anumberofoversizedpartic1.eswereab1.etofa1.1.throughthegapwithoutbeingbroken.Consequent1.y,
48、theproductsizedistributionforthisfeedoreshowsashifttowardsthe1.argerpartic1.esizes,andthePsOva1.ueincreasesfrom4ramto4.7mm.Inspiteofthis,theNCRCwassti1.1.ab1.etoachieveareductionratioofa1.most4:1.WearA1.thoughnospecifictes1.swereconductedtodeterminethewearratesonthero1.1.softheNCRC,anumberofthecrush
49、ingtria1.swererecordedusingahigh-speedvideocamerainordertotryandunderstandthecomminutionmechanism.Byobservingpartic1.esbeingbrokenbetweenthero1.1.sitispossib1.etoidentifyportionsofthero1.1.swhichare1.ike1.ytosufferfromhighwearandtomakesomesubjectiveconc1.usionsastotheeffectthatthiswearwi1.1.haveontheper1.brmanceoftheNCRC.Notsurprising1.y,theregionthatshowsupasbeingtheprimecandidateforhighwearisthetransitionbetweenthef1.atandconcavesur
