影响圆锥破碎机的片状粒子的一些因素外文文献翻译中英文翻译.docx

影响圆锥破碎机的片状粒子的一些因素外文文献翻译中英文翻译.docx

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影响圆锥破碎机的片状粒子的一些因素外文文献翻译中英文翻译

翻译部分

英文原文

TECHNICALNOTE

SOMEFACTORSWHICHAFFECTTHEGENERATIONOFFLAKYPARTICLESBYACONECRUSHER

A．C．APLINGandN．B．BARRETTT

§DepartmentofMiningandMineralEngineering，UniversityofLeeds，LeedsLS29JT，UK

LindleyPlant，Heage，Derbyshire，UK

（Received6October1995,"accepted15March1996）

ABSTRACT

Theproductsfromaseriesofpilotscaletestshavebeenanalysedforsizeandflakinesstoevaluatesomeofthefactorsaffectingthegenerationofflakymaterialinaconecrusher．Twodifferentfeedsourcescharacterisedintermsofresistancetocrushingandtensilefailurewereusedtoevaluatetheinfluenceofcrusherset．feedrateandofmaterialtypeontheresultantproductcharacter．

Keywords

Industrialminerals；crushing；particlemorphology；comminution

INTRODUCTION

Aggregateproducersmustmeetbothsizeandshapespecifications．TheBS

FlakinessIndex

F.I.=Massflakymaterialinrange×100/Totalmassmaterialinrange

（1）

avoidsarigorousdefinitionofparticleshapebysimplyassigningparticlesaccordingtotheirabilitytopassaspecialslottedgauge．

Theshapeofcrushedproductdependsonthematerialcharacteristicsandthecomminutionmethod．Earlyworkconcludedthatimpactmachinesgivetheleastandconecrushersthemostflakyproductandlowreductionratiosfavourtheproductionofnon—flakyproduct【2】．Conecrushershavemuchlowerrunningcostsparticularlyforharderabrasivematerialsandareinwidespreaduseintheaggregateindustry．

THEPROGRAMMEOFWORK

WorkhasbeenundertakenwiththeObjectiveofevaluatingtheeffectsoffeedrateandcrushersettingonthegenerationofflakymaterialbyaconecrusherfromtwodifferentnaturalmaterials．Twofeedratesandfivecrushersetscoveringtherangeofthemachinewereused．Thelowerfeedrateensuredfreecrushing，withparticlescrushedindependentlyandloadeddirectlybythecrusherfaces．Ahigherlevelallowedmaterialbuildupinthecrusherfeedcavitygivingchokedconditionswhereloadingisachievedthroughaparticlebed．

THEMATERIALS

Thetwofeedmaterialswereofsimilarsize．Thefirstcontainedtwomajorrocktypes；carboniferouslimestone77％，andmillstonegrit（gritstone），23％（RedlandAggregates，Masham，NorthYorkshire），thesecondalsocontainedtwomajorrocks；ametamorphictypeknownlocallyas‘granite’，88％and‘shale’，12％（Tarmac，CliffHillQuarry，Leicestershire）．

Particlecharacterisation

FlakinessIndex【1】determinationwasundertakenforallmaterialslargerthan4．0mm．Forsmallersizes，amicroscopewasusedtodistinguishflakyparticlesandtheindexdeterminedfromtheweightsofthetwocategories．Aconversionfactorwasestablishedbetweenthemethods．Sizeanalysisofallmaterialswasdeterminedbystandardsieveanalysis．

Crushability

ThesimplerRockImpactHardnessNumber（RIHN）【3】wasusedratherthantherecommendedaggregatestrengthtests【4】whichrequireextensivelaboratoryapparatus．Itslinearrelationshipwithtensilestrength【5】，suggestsagoodcorrelationwithgenerationofparticlesbycleavage，animportantmechanisminthegenerationofflakyparticles【6】．TheCrushabilityWorkIndex（CWI）【7】wasdeterminedforcomparison．BothCliffHillspeciesweresubstantiallyharderthanthosefromMasham．

THEPILOTSCALETESTS

TestswereconductedusingaStandardSymons2-footConeCrusherfittedwithafinebowlhavingafeedopeningof57．2thin．andrecommendedminimumdischargesettingof6．4mm，【8】．Productsandfeedforeachoftwentytestswereanalysedforsizeandshape．

DISCUSSIONOFRESULTS

Fullanalyticalresults，presentedelsewhere【9】，allowthecharacterisationoftheproductsintermsof

1）themassfractionineachsizefraction

2）theflakinessindexofeachfraction

3）theflakinessindexofthetotalproduct

4）thedistributionofflakyandnon—flakymaterialbysize

andpermittedtheidentificationofconditionsfavourableforthegenerationofnon—flakymaterial．

Factorsaffectingsizedistributionofproduct

TheMashamproductwasgenerallyfinerthanthatfromtheharderCliffHillmaterialdue，inpart，toitscrushingbehaviour．OnlytheMashammaterialshowedanydifferencebetweenfeedrates，generatingmorefinesduringchokefeeding．Thegranularstructureofthismaterialwouldtendtoencouragethis．AtendencyforthecrushingfacestobeforcedapartbytheharderCliffHillfeedundercrowdedconditionswouldreduceitsproductionoffines．

FactorsaffectingFlakinessIndexofdifferentsizes

ThepatternillustratedinFigure1wasobservedinallcases．Productflakinessof100%atthelargestsize，fallsassizedecreases，passingthroughaminimum，beforethenincreasing．Alllargerparticlestendtobeflakybutatdecreasingsetparticlesofsimilarsizehavetobeincreasinglyflaky（thin）toenablepassagethroughthecrushercavity．

FortheMashamfeedtheflakinessofcoarsersizesisslightlylowerforchokefeeding，moreespeciallyatfinersets．suggestingthatundertheseconditionsflakymaterialismorelikelytobebrokenasaconsequenceoftherestrictedopportunitiesforfavourableorientationwithinthecrushingchamber．

Fig．1FlakinessIndexversussize--MashamProductsfordifferentfeedratesandcrushersets

Inallcasesthesizeatwhichflakinessindexisaminimumisbroadlyrelatedcrusherset，increasingasthecrushersetincreases．Overallproductflakiness，calculatedastheweightedmeanoftheindexforindividualsizefractionsisgenerallylessunderchokefeeding，andreducesassetdecreases．

Factorsaffectingsizesforpeakproduction

Fig．2Productdistributionbyshapeandsize--Mashamchokefeedingacstatedstatedsets

Analternativemeasureofproductcharactergivenbythedistributionofflaky（F）andnon—flaky（N）materialbysize，illustratedinFigure2，alsorevealsdifferencesinbehaviour．

Examinationofthedatarevealed，despitethescatteroftheresults，thatforbothmaterials

（1）peakproduction（bothshapes）isrelatedtosetandinallcasestendstoincreaseandoccurinlargersizesassetincreases．

（2）peakflakeproductionoccursinasizelargerthanthatfornon—flake

Peakflakeandnon-flakeproductionissimilarunderdifferentfeedconditionswiththeCliffHillmaterialbutincreasesandoccursathighersizesassetincreases．whilstfortheMashamfeedmaximumproductionoccursatincreasingsizebutflakeproductiondecreaseswhilstnon-flakeincreases．Chokefeedingconditions，especiallyatfinersets，tendstoresultinmorenon—flakeand1essflakeproductionalthoughtheeffectontheCliffHillmaterialisnoticeableonlyatthefinestset．Largesizesconsistalmostentirelyofflakymaterialwhichescapesbreakageduetofavourableorientation．

GeneralDiscussion

Iftheformoftheproductsizedistributionissimilarthenasmallercrushersetshouldreduceoverallflakinesssinceanyincreaseinflakinessofthecoarsersizeswillbecounterbalancedbyanincreasedproportionofnon—flakyfinersizes．FortheMashamfeedthistendstobethecase．TheresultsforCliffHillare1essclear．Earlierwork[2]suggestedthatflakinessdecreasesathighfeedratesandalsoatlargercrushersets．Theseresultsappeartocontradictthelatterfinding．Howeveroverallflakinessmaskstheeffectsonindividualsizefractions，someofwhichmaynotberequiredasproduct．Largersizedftakyparticlesgeneratedbycrushingatlargesetscouldpresumablyberemovedbyscreeningleavingthefinernon—flakeasproduct．

Theincreasedpeaknon—flakeproductionforlargercrushersetswiththeweakerMashammaterialsuggeststhattheseconditionsfavourthegenerationofaproduct，followingrejectionofcoarsesizesbyscreening，oflowflakiness．

Contrarytoearlierwork[2]theminimumflakinesssizeisalwayslessthanthesizeatwhichtotalproductionisamaximumanddoesnotcorrespondtothesizeofmaximumnon—flakeproduction．Equivalenceofthesetwosizeswouldclearlygeneratethemaximumquantityofnon．flakyproduct，normallytheobjective．Theratioofmaximumproductionsizestominimumflakinesssizeallowsexaminationoftheeffectofcrushingconditionsonnon．flakeproduction，showninFigure3，revealingabroadtrendforthesesizestoapproacheachotherascrushersetdecreases．Thissuggeststhatthemostfavourableconditionsoccurforsmallersets，thatiShighreductionratios．Althoughpeaknon—flakeproductionincreasesassetincreasesitisaccompaniedbygreaterflakeproductinthesamesize．

Thedilemmatheniswhethertherequirementismaximumproductionofnon—flakeandthatgenerationofflakymaterialinthesamesizeisnotaproblem．inwhichcasealowreductionratioseemstoberequired．orwhethertheminimumflakinessindexiSrequired．thatisthegenerationofflakymaterialiStobeminimisedinaparticularsize．Ifthisisthecasethenamuchsmallersetseemstoproducetherequiredresult．Thechoicethenisbetweenmaximumproductionofnon—flakeorminimumflakinessindex．Inrealityacompromisebetweenthetworequirementswilloftengeneratethemaximumproductoftherequiredspecificationandclosecontrolonthesetofthecrushingmachineswillberequiredtoensureoptimumconditionsaremetatalltimes．

Thelargevariationinthedataleadstoadegreeofuncertaintyinrelationtoitsinterpretationandreflectsthedifficultyofobtainingdatainrelationtolargesizedmaterial，neverthelessitisbelievedthatsomeimportanttrendshavebeenidentifiedwhichareofrelevancetotheperformanceofconecrushers．Theworkherehighlightstheimportanceofgatheringfurtherinformationinorderproperlytoquantifytheseeffects．

Fig．3Sizeratioversuscrusherset

CONCLUSIONS

Thebroadconclusionsreachedfromthecurrentworkcanbesummarisedasfollows；

1.Maximumflakinessoccure