硫化钠对氰化抑制黄铁矿浮选的作用机理

ZhaoCAO1,2,3,PengWANG1,Wen-boZHANG1,Xiao-boZENG4,Yong-danCAO1

1.InstituteofMiningEngineering,InnerMongoliaUniversityofScienceandTechnology,Baotou014010,China;2.GuangdongInstituteofResourcesComprehensiveUtilization,Guangzhou510650,China;3.StateKeyLaboratoryofRareMetalsSeparationandComprehensiveUtilization,Guangzhou510650,China;4.InstituteofMultipurposeUtilizationofMineralResources,ChineseAcademyofGeologicalScience,Chengdu610041,ChinaReceived3June2019;accepted19November2019Abstract:Themechanismofsodiumsulfide(Na2S)ontheflotationofcyanide-depressedpyriteusingpotassiumamylxanthate(PAX)ascollectorwasinvestigatedbyflotationtestandelectrochemicalmeasurements.TheflotationresultsshowthatbothPAXandNa2Scanpromotetheflotationrecoveryofcyanide-depressedpyriteandtheircombinationcanfurtherimprovethepyriteflotationrecovery.ElectrochemicalmeasurementsshowthatPAXandNa2Sinteractedwithcyanide-depressedpyritethroughdifferentmechanisms.PAXcompetedwithcyanideandwasadsorbedonthepyritesurfaceintheformofdixanthogen,thusenhancingthehydrophobicityandflotationofcyanide-depressedpyrite.UnlikePAX,Na2Srenderedthepyritesurfacehydrophobicthroughthereductionofferricyanidespeciesandtheformationof

elementalsulfurS0andpolysulfideS2n.ThecombinedapplicationofPAXandNa2SinducedsuperiorpyriteflotationrecoverybecauseofasynergisticeffectbetweenPAXandNa2S.Keywords:pyrite;chalcocite;flotation;cyanide;depression;sodiumsulfide1Introduction

Goldgenerallyexistsinmostcopper−goldoresasfreegold,copper-associatedgoldandpyrite-associatedgold,whichareusuallyrecoveredbygravityseparationandsequentialflotationwherecopper-bearingmineralsarefirstfloatedtoasaleablecopper−goldconcentratewithpyritetobedepressed,andthenthedepressedpyriteisactivatedandfloatedtorecovertheassociatedgold[1,2].Chalcopyriteandchalcocitewidelyexistasprimaryandsecondarycopper-bearingminerals,respectively,inmostcopper−goldores.Inthepreviousstudy,wefoundthatthedepressedpyriteinchalcopyriteflotationbylimecouldbefloatedby

theadditionofPAX(potassiumamylxanthate)orNa2Sthroughdifferentmechanisms[3].WhiletheadditionofPAXremovedthehydrophilicmetaloxidationspecies,followedbytheadsorptionofPAXonpyritesurface,theadditionofNa2Sformedelementalsulfurandpolysulfideonpyritesurface,bothofwhichincreasethehydrophobicityofpyrite[3].

However,thechalcocite-dominantcopperoresaremoredifficulttotreatbecausemorecopperionsemanatefromchalcocitethanfromchalcopyritetopromotestrongercopperactivationonpyrite[4−6].Inthiscase,limeisnotanefficientpyritedepressantandcyanideisoftenrequiredtodepresspyriteincopperflotation[7].

Differentmechanismshavebeenproposedto

Foundationitem:Project(51764045)supportedbytheNationalNaturalScienceFoundationofChina;Project(NJYT-18-B08)supportedbyInnerMongoliaYoungScience&TechnologyTalentSupportPlan,China;Project(GK-201804)supportedbyResearchFundProgramofStateKeyLaboratoryofRareMetalsSeparationandComprehensiveUtilization,China;Project(DD20190574)supportedbyChinaGeologicalSurveyProjectCorrespondingauthor:Xiao-boZENG;Tel:+86-13880745178;E-mail:42881697@qq.comDOI:10.1016/S1003-6326(20)65228-1ZhaoCAO,etal/Trans.NonferrousMet.Soc.China30(2020)484−491485explainFORSSBERGpyritedepressionpreferentially[8]foundbycyanide.thatWANGandcyanideandcompounds,adsorbedonpyritesurfacecyanideaswasironflotation.oxidationofxanthateinhibitingonthepyritechemisorptionandpyritecyanidereducedhinderedHowever,thedeWETetal[9]suggestedthatpreventedthemixedpotentialelectrochemicalofpyritesurface,activitieswhichandandetthendepressedtheoxidationpyriteofxanthatetodixanthogenadsorptional[10]haveconfirmedflotation.thattheRecently,preferentialGUOspeciespotentialratherofcyanidethantheondecreasepyriteasferricyanidedepressionwasofpyriteredoxcopperagent,ions,bycyanide.mainlyresponsibleforpyritecyanideWhenactspyriteasisactivatedbypyritecyanidesurfacewhichremovescuprousionsafromdeactivatingactivatedcomplexesviathesuchformationasofstrong2cuprous

xanthates,Cu(CN)34byselectivelydissolvingCu(CN)3cuprous-and

cyanideeffectand-sulfidescopperionsandco-exist,-oxides[11].Whentheofcuprouscyanideonpyriteisthedependentdepressiononsolution.redoxaAspotentialdemonstratedandbyCN/CumoleratioinandreducingenvironmentpromotesGUOtheandcopperPENGuptake[12],cyanideformationofsolution,ofcoppersulfideonpyriteincoppercyanidedepressingit,whilstwhichatmayaactivatepyriteinsteadisbeneficialdissolvestheformedhighcopperCN/Cusulfide,molewhichratio,byTorestoretopyritethefloatabilitydepression.

ofpyritedepressedetagentsalcyanide,[13]someactivatorsmaybeused.LVperoxidesuchandassodiumYANGetal[14]usedoxidizingdepressedtoattributedpyrite.activatethehypochloriteflotationandofhydrogencyanide-whichtotheoxidationTheactivationofcyanidemechanismtowasonformaldehydepyriteeliminatedflotation.thedepressioneffectofcyanatecyanidedepressedtoactivateREDDYtheflotationetalof[15]usedcouldandreactsphalerite,withzinccyanideandfoundthatformaldehydecyanide-surface,desorbthecyanidelayertoformfromcyanohydrinssphaleriteHowever,resultinginefficienttheyfoundinimprovedthatsphaleriteformaldehydeflotation.wasdepressedonpyritetoactivatebecausetheironflotationofcyanide-formaldehyde.

pyriteweretoostabletocyanideberemovedcompoundsbyusedItpyritetohasactivatebeenreportedthatsodiumsulfideismineralsandsometheflotationotherofoxidecyanide-depressedbasebeensulfidecarried[1,16−18].wasinthisoutHowever,fewstudiesmetalhavesystem.tounderlineIntheeffectofsodiumanddepressedinchalcocitetheflotationcurrentstudy,bypyriteadditionthedepressedpyritewasthenfloatedwithcyanidethemechanismofpyriteofsodiumsodiumsulfidesulfide.onTheactivationments.wasstudyTogetherstudiedwithbycyanide-depressedtheelectrochemicalmeasure-enhancementmayprovideofcyanide-depressednewperspectivespreviouspyrite.

onstudythe[3],flotationthis2Experimental

2.1Materials

purchasedThechalcocitewerefromGEOandDiscoveries,pyritepuremineralswerefractionsbothcrushedinlaboratory,andAustralia.0.71−3.35TheymmElementalwereresultsanalysiscollectedandfromX-raythecrushedmaterial.puritiesThewereshowedthatthepyritepowderanddiffractionchalcocite−20°Ccrushedtoeliminatesamples96.0wt.%thewereand96.4wt.%,respectively.surfacekeptinarefrigeratoratchalcociteRTA11Axanthateflotation(dithiocarbamate)oxidation.

collector,wasusedasthecollector,(PAX)wasusedasthepotassiumpyriteflotationamylusedpurityasallandtheandwerefrother.DSF004(analiphaticalcohol)wasuseddirectly.TheywereOtherallofindustrialwithanalyticalreagentgrade.Deionizedchemicalswaterwere(DI),experiments.

aresistivityof18MΩ/cm,wasusedinall2.22.2.1Methods

with10Flotationless100gmLchalcocitetests

waterandandground90gtopyrite80weremixedstainlessthanaddedsteel106μmgrindinginarodmedia.millwt.%particlesThenfor4.8theminpulpusinglimetoa1.5Lflotationcellandconditionedwas12DSF004g/tandRTD11Asodiumcyanideaspyritedepressantswithandforcollected2min.asfrother.aschalcocitecollectorand30g/tFourEachchalcocitereagentconcentrateswasconditionedwereflotationtimeatanof1,air2,3flowand4rateminoffor6eachL/minone.

with486ZhaoCAO,etal/Trans.NonferrousMet.Soc.China30(2020)484−491needed),Afteradded2toPAXchalcocitechalcocite(ifneeded)flotation,tailingandsodiumsulfide(ifand30g/tconditionedDSF004wereforpyriteminsulfideflotationbeforepyriteflotation.ThenaturalpHinsolutionwas9.Whenwithoutsodiumthesulfideadditionwasofsodiumaddedwithaconcentrationof1mmol/Ladded,HClwasconcentratestomaintaineachwerecollectedpH9.inFourpyriteflotationconcentratesone.Allthe1,2,3and4minforassayedandtailingschalcocitewereanddried,pyriteweightedflotationandrecoveriesforchalcociteandpyritegrades2.2.2Electrochemicalcalculation.

andmeasurements

measurementsInthiswork,interactionwereconductedcyclicvoltammetrytounderstand(CV)depressedofPAXandNathe2Swithcyanide-withpyrite.TheexperimentwasperformedmicroscopeCHIconventional(CH920DInstruments,scanningInc.,electrochemicalUSA)withadouble-layerthree-electrodeelectrochemicalcell.Aelectrochemicalwall200cellglasswithreactoraneffectivewasusedastheelectrolyte,mL.AAg/AgClelectrodein3mol/LvolumeKClofareaof1cma2platinumplateelectrodewithasurfaceusedelectrodes,astheandreference,thepolishedpyriteelectrodewereagainstatheAg/AgClrespectively.Potentialscounterwereandmeasuredworkingelectrodepotentialof220mVreferenceagainstaelectrodestandardwhichhydrogenhaseachTheexperiments(SHE).

wereconductedinair.Beforerenewedtest,carbideseveralpaperbythewetsurfaceandpolishingofpyriteelectrodewasrinsedusingwith1200deionizedgritsiliconwaterwascommencedconductedtimes.Openbeforecircuiteachpotential(OCP)sweepapproximatelywhenperformed10theOCPCVwasexperimentstabilizedwhich(aftergoinggoingpotentialfromscan),themin).OCPInCVthentotostudies,cycleswere−800600mVmV(apositive-scanpotentialscan)andthenbacktothe(anegative-OCPforrateof20mV/s.FourcycleswereperformedatabecauseeachoxidizedsecondorthetestandreducedshapethesecondcyclewasadoptedspeciesandthebecamepeakstableintensitysincetheofandExperimentsscan.

andpresencewereperformedintheabsencePAX,individuallyofsodiumandcyanide,incombination.sodiumsulfideThe

reagentsodiumwasaccordingsulfideadded(ifinneeded)theorderandofPAXsodiumcyanide,electrodesolutionwastoconditionedtheflotationfor15procedure.(ifneeded)mininelectrolytePyritereachaftertheadditionofeachreagenttoelectrochemicaltheadsorptionelectrolytemeasurement.equilibriumbeforethe(KClOwas0.1mol/LpotassiumThebackgroundperchlorate1mol/L4)KOHsolutionsolutionandthe[19].

pHwasadjustedto9with3Resultsanddiscussion

3.1Flotation

RTD11AChalcocitedepressed.asfunctionFiguretheflotationwasconductedfirstwith1collectorshowswhilepyritewas10.additionWhenofthecopperpHwasrecoveryadjustedfromcopperbythelimeflotationgradewithoutataspHathe96.4%gradeofofcyanide,theflotationproducedaboutaboutaftercopper10minrecoveryflotation.ataboutPyrite45.1%recoveryofcopperwasstudylime[3]11.6%.whereThispyriteiswasdifferentcompletelyfromthedepressedpreviousbyreportedatpHactivethat10chalcociteinchalcopyriteismoreflotation.electrochemicallyIthasbeeninteractionthanthanmorebetweenisstrongerchalcopyrite,andthegalvanicchalcopyritebetweenchalcociteandpyritepyritecopperdifficultsystemionstoactivateareavailableandpyritefromthe[6].chalcocite−Therefore,bylime.

depressionofpyritepyrite,inchalcociteresultingflotationinmoreNaCNFigureincreased1alsocoppershowsgradethatthesignificantlyadditionofto20057.3%g/tFig.1CoppergradeasfunctionofcopperrecoveryinchalcociteflotationwithpyritedepressedatpH10ZhaoCAO,etal/Trans.NonferrousMet.Soc.China30(2020)484−491487whilePyritedecreasingofactivationrecovery.wascompletelycopperrecoveryslightlyto94.2%.GUOetdepressedwithabout2.6%besolublemitigatedofcopperbycyanideionsal[20]ondemonstratedthattheduepyritetotheflotationformationcouldofconductedAftercuprouschalcocitecyanidecomplexes.

cyanide.torecoverflotation,thepyriteflotationwastheirdepressedcombinationInthepreviouswerestudypyriteadopted[20],PAX,depressedNaby2Sandapproachespyrite.Inthecurrenttoactivatestudy,lime-depressedAspyritewereandtakentheresultstoareactivateshownincyanide-theseFig.2.2.2%canbeseen,pyriterecoverywasonlyaboutpreviousintheabsenceofNa2SandPAXduetotheHowever,depressioninchalcociteflotation.ablethepresenceofeitherNa2SorPAXexample,topromotesufficientpyriteflotation.wasFor68.3%29.8%,atpyriteand48.7%,15g/trecoveryand30g/tincreasedPAX,respectively,to42.6%andandhydrophobic480g/tNa55.4%and63.5%at120,240,3602S,respectively.ThisindicatesthatthethatpresenceproductsofNaformedonpyritesurfacein2SorPAX.Figure2alsoshowspyritethereachedflotation.combination90%at30Asg/tcanofNaPAXbe2Sandseen,and480pyritePAXenhancedg/tNarecovery2S.

Fig.2EffectofPAX,Na2SandtheircombinationonflotationofpyritedepressedbycyanideinchalcociteflotationatpH9indicatingBothNa2SandPAXarereducingagents,pyritefollowingmayinvolvethatactivationelectrochemicaloncyanide-depressedNasection,theelectrochemicalreactions.reactionsIntheof2investigated.

SandPAXwithcyanide-depressedpyritewere3.2ElectrochemicalunderstandCycliccyanide-depressedthevoltammetryanalysis

reactionsof(CV)Nawasusedto2SandPAXpyritepyrite.Firstly,theCVcurvewithofbackgroundelectrodeshownsolutionin0.1atmol/LpotassiumperchlorateandcathodicA2)inFig.on3,therewerepHtwo9wasanodicobtained.peaks(A1AssweepanodicinpeaksthetheCV(C1positive-goingcurveandC2)onthesweepnegative-goingandtwopyriteandresultingpeakA1inwastheattributedofpyriteelectrode.Theformationtotheoxidationofsulfurasulfur-richsulfide(S0),polysulfidessublayer(FeSwhichofmayferricbehydroxide,elementalnshownin(FeEq.(1).

)[21].Thesurface)andreactionmetal-deficient1−xS2forA1isFeS2+3H2O=Fe(OH)3+2S0+3H++3e

(1)

ofPeakA2Eq.pyrite600mV(2)toferricwashydroxideduetotheandaggressivesulfateasoxidationshownin[22].

whentheupperpotentialincreasestoFeS2+11H2O=Fe(OH)3+2SO42−

+19H++15e

(2)

ofprocess.theTheoxidationcathodicspeciespeaksresultedformedfromduringthethereductionferricwashydroxidePeakC1towasferrousattributedhydroxidetothewhilereductionanodicpeakC2ofHS−relatedandC2[10,17].toareshownThethereactionsreductioninEqs.(3)responsibleofelementaland(4),respectively.forpeakssulfurC1toFe(OH)3+e=Fe(OH)2+OH−(3)S0+H2O+2e=HS−+OH−

(4)

electrodeFigurein4theshowspresencetheofCV0.2curvesmmol/LofNaCN,

pyriteFig.solution3CVatpHcurve9ofpyriteelectrodeinbackground488ZhaoCAO,etal/Trans.NonferrousMet.Soc.China30(2020)484−491Fig.4CVcurvesofpyriteelectrodeinthepresenceof0.2mmol/LNaCNwithoutandwithadditionof0.05or0.2mmol/LPAXatpH9withoutPAX.andwiththeadditionof0.05orandofaIncathodicthepresencepeakC3ofappearedNaCN,ananodic0.2peakmmol/L

A3formationpyriteelectrode.surfaceofferricyanidePeakA3ontheCVcurveFe(CN)was3−

duetothe

usingreactionsurfacewhichenhancedwasconfirmedRamanbyspectroscopy.GUO6onetalpyriteThis[10]atFe(CN)−0.35is3−mVshownandinresultedEq.(5).fromPeaktheC3reductioncommencedof

6toFe(CN)4−

6asshowninEq.(6)[23].

FeS2+8CN−=Fe(CN)63−+2SCN−+3e(5)Fe(CN)63−+e=Fe(CN)6

4−(6)

ofPeaksA3andC3whichpresenceFe(CN)3−

indicatetheformation

evenof60.2andmmol/Litsreduction,NaCNrespectively,inthe0.2PAX,mmol/LdisappearedPAX.Afterafterthetheadditionadditionbothweakenedofof0.05ororCV0.2curvetwonewofpyritepeakselectrodeA4andC40.2mmol/Linappearedontheattributedmmol/LdixanthogentoNaCN.theTheseoxidationtwoofnewthepresenceofxanthatepeaksweretoxanthate[24−27].asshowninEq.(7)anditsreductionto2X−=X2+2e

(7)

ofsurface,cyanideFigurespecies4clearlybyindicatesPAXcanthattaketheplacedisplacementonpyriteformedaccompaniedonwhichpyritemeansthatthecyanidespecieshigherbythesurfacecanberemovedbyPAX,indicatedPAXthatconcentration.formationinsolublehydroxylWANGofdixanthogenataferricetxanthate

al[28](Fe(OH)XalkalineFe(OH)XpH2)couldrange.beformedTheformationintheweaklyofinsolubleacidictoferricyanide2maydrive3−

thedisplacementof

as

(Fe(CN)6)frompyritesurfacebyPAXFe(CN)3−

6+OH−+2X−=Fe(OH)X2+6CN−

(8)

canbeThecalculatedGibbsfreeasfollows:

energychange(ΔrG)forEq.(8)rGrGRTln[Fe(OH)X[Fe(CN)32][CN]66][OH][X]2RTln1KFe(CN)36KspFe(OH)X2RTln[Fe(OH)X[Fe(CN)32][CN]66][OH][X]2(9)

where8.314RandTaretheidealgas298.15J/(mol·K)Fe(CN)K,3−

respectively.andthermodynamicconstantofThestabilityconstanttemperature(K)ofof

constant6is1043.6andthesolubilityOH−activitiesconcentration(KofFe(OH)Xproductsp)is2is10−35.5[28].AtpH9,3−

10−5mol/L.Assumingthatthe

pyrite−aqueousofFe(CN)free0.2energychangeinterface6andΔ[10],Fe(OH)Xthecalculated2areunityGibbsatrGforEq.(8)is−9.7negativemmol/LmeanssurfacethatGibbsNaCNthefreeand0.2mmol/LPAX.kJ/molTheatferricyanideenergyFe(CN)change3−

forEq.(8)

6onconcentration.coulddisplaceddixanthogen.

byAfterbedisplaced3−

byPAXatapyritehigh

PAX,Fe(CN)PAX6mayonpyritebeoxidizedsurfacetoisformationThetheofdisplacementdixanthogenmayofbeferricyanideresponsibleandforpresenceflotationofPAXofpyriteasshowndepressedbycyanideintheelectrodeFigurewithoutNaandin5showstheinCVFig.2.

curvesofpyritewiththethepresenceadditionofof0.20.1mmol/LorNaCNwhichreduction,indicatepH9.Itthecanformationbeseenthat0.4mmol/L2SatofFe(CN)peaksA33−

andC3

6anditsdisappearedrespectively,Naaftertheforththeadditionbothadditionofweakened0.1ofororevenNa0.4mmol/L2S.Inaddition,2SbroughtpeakA5isC5anewattributedontheanodicpeakA5andanewcathodictoCVthecurveoxidationofpyriteofelectrode.PeaktheelementalS0speciessulfurmayreact(S0)withasshownsulfideions(S2−to)asubtendinginEq.disulfide

(10)andZhaoCAO,etal/Trans.NonferrousMet.Soc.China30(2020)484−491489Fig.5CVcurvesofpyriteelectrodeinthepresenceof0.2mmol/LNaCNwithoutandwithadditionof0.1or0.4mmol/LNa2SatpH9layer(S2−(S2−

2)onpyritesurfacetoproducepolysulfideFe(CN)n)[29].3−

PeakC5isattributedtothereductionof

formation6onpyritesurface,resultingshowninEq.ofFeS(11)in[30,31].

thepresenceofsulfideinionstheasS2−=S0Fe(CN)+2e

63−

+S2−+e=FeS+6CN−(10)

(11)

increasedThecurrentintensityofpeakA5inFig.5whichwiththeincreaseofNa2Sconcentration,sulfur/polysulfidesuggeststhehigherS0formation2−

ofmoreelemental

peakelementalC2Na/Snonpyritesurfaceatawhich2Sconcentration.wasThecurrentintensityofincreasethatofsulfurNatoHSattributed−alsotoincreasedthereductionwiththeof2Sconcentration.pyritemoreelementalsulfur/polysulfideThisalsoformedsuggestsonreportedsurfaceatahigherNa2SconcentrationasthebyWALKERetal[32].Itwasnotedthat0.4currentintensityofpeakC5withtheadditionofthemmol/LbecauseadditionNaof2S0.1wasmmol/LslightlyNalowerthanthatwith2S.ThismightsurfaceconcentrationinlesstheFe(CN)3−

be

presence6couldofcyanidebeformedwhenonahigherpyrite(S2−reaction)BasedandonoftheNa2aboveSwasoxidationadded.

3−

ofsulfideions

beexpressedofreductionNaofFe(CN)6,theoverallredoxas

2Swithcyanide-depressedpyritecan2Fe(CN)3−

6+3S2−=2FeS+S0+12CN−

(12)

energiesThespeciesinEq.(12)andtheirstandardfreeGibbs’freeofformationenergychangeareshown(ΔinTable1.TherG)ofEq.(12)is

−25.58thiskJ/mol,anegativevalue,confirmingthatEquationreactionofascyanide-depressed(12)wouldmaybebethermodynamicallypossible.showninFig.2.

pyriteresponsibleinthepresencefortheflotationofNa2STable1Fe−S−CNspeciesandtheirstandardfreeenergiesofformationSpeciesΔfGΘ/(kJ·mol−1)Ref.Fe(CN)3−

6

694.92[10]S2−85.8[33]FeS−113.4[34]S00[34]CN−

172.38[10]electrodeFigure6theintheshowspresencetheof0.2CVmmol/LcurvesNaCNofpyrite

withPAXadditionPeaksindividuallyof0.4andmmol/LincombinationNa2Sand0.2atmmol/LformationA4andofofdixanthogenA5whicharepH9.dueresponsibletoforthesulfur/polysulfidexanthateandionsduethetoformationtheoxidationtheoxidationofofelementalon0.4theonpositive-goingpyritesurface,scanrespectively,ofpyriteelectrodebothappearedsulfidewheninrendercombination.mmol/LNa2STheseand0.2hydrophobicmmol/LPAXproductswereaddedClearly,thetimetheadditionpyritesurfaceofPAXstronglyandNahydrophobic.may2SdepressedcanfacilitatebycyanidetheatthesameinflotationofpyritepreviouslychangeFigureofcyanide-depressed7illustrateschalcocitethepyritesurfaceflotation.

inthechemistrypresence

Fig.0.2andmmol/L6CVcurvesNaCNofwithpyriteadditionelectrodeofinthepresenceofpH90.2mmol/LPAXindividuallyand0.4incombinationmmol/LNa2atS490ZhaoCAO,etal/Trans.NonferrousMet.Soc.China30(2020)484−491Fig.7Possiblereactionmechanismsofcyanide-depressedpyritewithNa2S,PAXandtheircombinationofNa2S,PAXandtheircombination.InthepresenceofPAX,thedisplacementofferricyanidebyxanthateionsandtheformationofdixanthogenmayberesponsiblefortheflotationofcyanide-depressedpyriteatahighconcentrationofPAX[8].UnlikePAX,Na2Spromotespyriteflotationthroughthereductionofferricyanidespeciesandtheformationofelementalsulfurandpolysulfide.TheadditionofPAXandNa2SatthesametimemayinducesuperiorpyriteflotationasaresultofthecombinedactionsfromPAXandNa2S.

[2][3][4][5]4Conclusions

(1)BothPAXandNa2Scanbeusedtofloatpyritedepressedbycyanideinchalcociteflotation.However,theircombinationisbetterthaneachofthemtoimprovetheflotationofcyanide-depressedpyrite.

(2)Differentmechanismscouldbeusedtounderlinetheflotationenhancementofcyanide-depressedpyritebyPAXandNa2S.PAXcancompetewithcyanideandbeoxidizedtodixanthogenonpyritesurface,whereasNa2ScanreducetheferricyanidespeciesonpyritewiththeformationofelementalsulfurS0andpolysulfide2−Sn.Therefore,thehydrophobicityandfloatabilityofpyritecanbeimprovedbybothPAXandNa2S.Moreover,theapplicationofPAXandNa2SatthesametimecanfurtherenhancethehydrophobicityandfloatabilityofpyritebecauseofasynergisticeffectbetweenPAXandNa2S.

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1.内蒙古科技大学矿业研究院，包头014010；2.广东省资源综合利用研究所，广州510650；3.稀有金属分离与综合利用国家重点实验室，广州510650；4.中国地质科学院矿产综合利用研究所，成都610041摘要：通过浮选试验及电化学测试，研究戊基黄原酸钾(PAX)为捕收剂时硫化钠对氰化抑制黄铁矿浮选的作用机理。浮选结果表明，PAX和硫化钠单独使用时都可以提高氰化抑制黄铁矿的浮选回收率，但二者组合使用时对PAX与硫化钠在氰化抑制黄铁矿的表面具有不同的作用形式，PAX回收率的提升效果更加显著。电化学结果表明，可取代黄铁矿表面的氰根并以双黄药形式吸附于黄铁矿表面，导致黄铁矿表面疏水及可浮；而硫化钠可还原黄铁矿表面的铁氰化物并在黄铁矿表面生成单质硫和多硫化物，进而使黄铁矿表面疏水。组合使用时由于二者的协同作用会进一步提高黄铁矿的浮选回收率。关键词：黄铁矿；辉铜矿；浮选；氰化物；抑制；硫化钠(EditedbyXiang-qunLI)