A STUDSTUDYY OOFF INTEGRATEINTEGRATEDD LEACHINLEACHINGG ANANDD ELECTROWINNINGELECTROWINNING
OOFF COPPECOPPERR FROFROMM CHALCOPYRITCHALCOPYRITEE OREORE
USINUSINGG CHLORIDCHLORIDEE MEDIAMEDIA
bbyy
PrashanPrashantt KumaKumarr SarswatSarswat
A thesithesiss submittedsubmitted toto ththee facultyfaculty ofof ThThee UniversitUniversityy ofof UtahUtah iinn partiapartiall fulfillmenfulfillmentt ofof ththee requirementrequirementss foforr ththee degredegreee ofof
MasterMaster ofof ScienceScience
DepartmentDepartment ofof MetallurgicalMetallurgical EngineeringEngineering
TheThe UniversityUniversity ofof UtahUtah
MayMay 20102010 CopyrighCopyrightt © PrashanPrashantt KumaKumarr SarswaSarswatt 20102010
AlAlll RightRightss ReservedReserved THE UNIVERSITY OF UTAH GRADUATE SCHOOL
SUPERVISORY COMMITTEE APPROVAL
of a thesis submitted by
Prashant Kumar Sarswat
This thesis has been read by each member of the following supervisory conunittee and by majority vote has been found to be satisfactory.
z reb w{O
Sivaraman Guruswamy � THE UNIVERSITY OF UTAH GRADUATE SCHOOL
FINAL READING APPROVAL
To the Graduate Council of the University of Utah:
Date Mi ael L. Free
C air: Supervisory Committee
Approved for the Major Department
Jan D. Miller Chair
Approved for the Graduate Council
arles MWight Dean of The Graduate School ABSTRACT
Hydrometallurgical recovery of copper from chalcopyrite ore using chloride media has several advantages over sulfate based processes: faster kinetics; high solubility of metals; easy oxidation of sulfides; reduced energy consumption step due to utilization of one electron per atom of copper formation, rather than two in most electrowinning operations; and conversion
from water hydrolysis to ferric ferrous half-cell reaction, which reduces cell voltage.
Disadvantages include corrosivity and reduced limiting current density during electrowinning.
A comparison of advantages and disadvantages indicates that leaching of sulfide ore or concentrate in chloride media may be advantageous. Several chloride media have been examined for copper extraction. Cupric chloride and ferric chloride solutions have already proven to be efficient leaching agents; ferrous chloride has been utilized for copper production by means of the Hunt and Douglas process. Cupric/cuprous ion ratio plays a vital role for leaching kinetics. Individually, ferric and cupric ions have proven to be good leaching agents; a combination of ferric/ferrous and cupric/cuprous ions has been explored in this research by conducting factorial design of experiments. Simultaneous leaching and clectrowinning is explored in this study as a way to reduce processing and energy costs. Electrowinning has been performed using a solution similar to that being utilized for leaching; factorial design experiments were also conducted to study various factors which affect electrowinning.
3 2 2 In summary, this study is focused on determining the effects of Fe +, Fe +, Cu +, Cu+ and
acid concentration on leaching of chalcopyrite as well as the electrowinning of copper from the
------resultinresultingg leachingleaching solutionsolution usinusingg a chloridechloride mediummedium.. A lablab scalescale designdesign ooff experimentsexperiments forfor integrateintegratedd leachinleachingg anandd electrowinninelectrowinningg ooff coppecopperr fromfrom ororee iiss discusseddiscussed.. PossiblePossible variationvariationss ofof experimentalexperimental parameterparameterss ttoo improveimprove performancperformancee araree alsalsoo discusseddiscussed.. ResultResultss showeshowedd thathatt highhigh hydrochlorihydrochloricc acidacid andand cupriccupric ioionn concentratioconcentrationn assisteassistedd leachingleaching;; oonn ththee otheotherr hand, electrowinningelectrowinning ofof coppecopperr frofromm chalcopyritechalcopyrite ororee leachinleachingg solutionsolution usinusingg chloridchloridee medimediaa iiss muchmuch feasiblefeasible whewhenn aciacidd anandd cupricupricc ioionn concentrationconcentrationss areare lowlow (0.0(0.055 M/Mill anandd 0.00.011 MM/lil,, respectively).respectively).
v TABLTABLEE OOFF CONTENTSCONTENTS
ABSTRACABSTRACTT ...... iviv
LISLISTT OOFF TABLETABLESS ...... viiviiii
ACKNOWLEDGEMENTACKNOWLEDGEMENTSS ...... ixix
ChapteChapterr
11.. INTRODUCTIOINTRODUCTIONN ...... 1
1.11.1 OvervieOvervieww ooff fundamentafundamentall ooff metametall leachinleachingg .. " ...... 1 1.21.2 OvervieOvervieww ooff fundamentafundamentall ooff metametall electrowinninelectrowinningg ...... 2 1.31.3 OvervieOvervieww ooff conventionaconventionall chalcopyritchalcopyritee processinprocessingg ...... 6 1.41.4 OvervieOvervieww ooff sulfidsulfidee basebasedd anandd chloridchloridee basebasedd mediamedia foforr coppecopperr electrowinningelectrowinning ...... 8 1.51.5 OverviewOverview oofleachingf leaching ofof chalcopyritchalcopyritee oreore witwithh ususee ofof ironiron chlorideschlorides andand coppercopper chloridechloridess ...... 1010
2.2. EXPERIMENTAEXPERIMENTALL PROCEDUREPROCEDURESS ...... 1212
2.12.1 ListList ooff chemicalschemicals usedused ...... 1212 2.22.2 LeachantLeachant compositioncomposition ...... '" ...... 1313 2.32.3 ElectrochemicalElectrochemical cellcell andand instrumentationinstrumentation ...... 1313 2.42.4 ExperimentalExperimental proceduresprocedures ...... 1414 2.4.12.4.1 ColumnColumn leachingleaching experimentsexperiments withwith electrowinningelectrowinning ...... 1414 2.4.22.4.2 FactorialFactorial designdesign columncolumn leachingleaching experimentsexperiments ...... 1616 2.4.32.4.3 FactorialFactorial designdesign electrowinningelectrowinning experimentsexperiments ...... 2020 2.4.42.4.4 ElectrowinningElectrowinning testtest matrixmatrix II.II ...... 2222 2.4.52.4.5 ImageImage analysisanalysis ...... 2424 2.52.5 DetailedDetailed leachingleaching kineticskinetics evaluationevaluation ...... 2424
3.3. RESULTSRESULTS ANDAND DISCUSSIONDISCUSSION ...... '" ...... 2727
3.13.1 EvaluationEvaluation ofof primaryprimary combinedcombined leachingleaching andand electrowinningelectrowinning experimentsexperiments ...... 2727 3.1.13.1.1 ConsumptionConsumption ofof acidacid ...... 29 29 3.1.23.1.2 ConcentrationConcentration ofof coppercopper andand ironiron (ICPMS(ICPMS analysis)analysis) ...... 3030 3.1.33.1.3 RecoveryRecovery ofof coppercopper byby electrowinningelectrowinning ...... 3030 3.23.2 AnalysisAnalysis ofof factorialfactorial designdesign columncolumn leachingleaching experimentsexperiments ...... 3333 3.3.33 AnalysiAnalysiss ooff leachin leachingg experimentexperimentss ...... 4040 3.3.3.3.11 ModeModell 11:: sphericasphericall particlparticlee undeunderr reactioreactionn controcontrol..l ...... 4242 3.3.3.3.22 ModeModell 22:: sphericasphericall particlparticlee undeunderr producproductt layelayerr controcontrol..l ...... 4343 3.3.44 AnalysiAnalysiss ooff factoriafactoriall desigdesignn electrowinninelectrowinningg experimentexperimentss ...... 4646 3.4.3.4.11 ComparisoComparisonn ooff currencurrentt efficiencefficiencyy (experimenta(experimentall anandd simulatedsimulated)) ...... 4646 3.4.3.4.22 AnalysiAnalysiss ooff electroplateelectroplatedd samplsamplee ...... 662 2 3.4.3.4.33 FactoriaFactoriall desigdesignn analysianalysiss ooff experimentexperimentss ...... 6655 3.3.55 AnalysiAnalysiss ooff electrowinninelectro winningg testestt matrimatrixx IIII ...... 6699
44.. CONCLUSIONCONCLUSIONSS ...... 7733
AppendiceAppendicess
AA.. IMAGEIMAGESS OOFF ELECTROPLATEELECTROPLATEDD SAMPLESAMPLESS ...... 757 5
BB.. CONCENTRATIOCONCENTRATIONN OOFF IONIIONICC SPECIESPECIESS ...... 78 78
CC.. EXPERIMENTAEXPERIMENTALL ANANDD SIMULATESIMULATEDD CURRENCURRENTT DENSITYDENSITY ANANDD CURRENCURRENTT POTENTIAPOTENTIALL RELATIONSHIRELATIONSHIPP FOFORR DIFFERENDIFFERENTT TESTTESTSS ...... 8484
REFERENCEREFERENCESS ...... 8787
Vllvii LISLISTT OOFF TABLESTABLES
TablTablee PagePage
2.12.1:: LeachinLeachingg solutiosolutionn detaildetailss foforr combinecombinedd leachinleachingg anandd EEWW testtestss ...... 1616
2.22.2:: ThreThreee - factofactorr desigdesignn ooff experimentexperimentss aatt highighh anandd loloww levellevelss ...... 1717
2.32.3:: FactoriaFactoriall desigdesignn testestt matrimatrixx foforr leachinleachingg anandd electrowinninelectrowinningg ...... 2121
2.42.4:: ElectrowinninElectrowinningg testestt matrimatrixx IIII ...... 2323
3.13.1:: FactorialFactorial desigdesignn analysianalysiss matrimatrixx foforr testtestss aass summarizedsummarized in Table 2.2, copper recovery is chosen as response variable ...... 38 in Table 2.2, copper recovery is chosen as response variable 38 3.2: Forward and backward constant values, estimated by sensitivity analysis ...... 60 3.2: Forward and backward constant values, estimated by sensitivity analysis 60 3.3: Factorial design matrix output for experiments, discussed in section 2.4.3 ...... 66 3.3: Factorial design matrix output for experiments, discussed in section 2.4.3 66 ACKNOWLEDGEMENTSACKNOWLEDGEMENTS
I wouldwould likelike toto expressexpress mymy smceresincere gratitudegratitude toto mymy parentsparents forfor theirtheir indefatigableindefatigable supportsupport throughouthroughoutt mmyy educationeducation.. MMyy deepestdeepest thankthankss areare duedue ttoo mmyy mothemotherr ManoramaManorama SharmaSharma forfor encouragingencouraging mmee frofromm childhood.childhood. I amam ververyy gratefugratefull foforr thethe excellentexcellent supportsupport ooff mmyy advisor,advisor,
ProfProf MichaeMichaell L.L. Free,Free, anandd ththee invaluablinvaluablee instructioinstructionn provideprovidedd bbyy mmyy supervisorysupervisory committeecommittee membersmembers,, ProProff S.S. Guruswamy,Guruswamy, andand ProfProf H.H. YY.. Sohn.Sohn. I gratefullygratefully acknowledgacknowledgee financialfinancial supportsupport provideprovidedd bbyy ththee CenteCenterr ooff AdvanceAdvancedd SeparationSeparation TechnologyTechnology (CAST).(CAST). ManManyy thankthankss gogo toto KareKarenn HayneHayness anandd KaKayy ArgylArgylee foforr excellenexcellentt support;support; ttoo AphicharAphichartt RodchanarowaRodchanarowann foforr hishis helhelpp anandd valuablvaluablee suggestions;suggestions; toto JuliJuliee VogeVogell foforr herher assistanceassistance inin somcsome ofof ththee experiments.experiments. I alsoalso acknowledgacknowledgee ththee excellentexcellent supportsupport ooff ththee membermemberss ooff ththee CorrosionCorrosion LabLab,, specificallyspecifically
SoumyaSoumya KarKar.. MMyy deedeepp sensesense ooff gratitudgratitudee isis foforr mmyy sistersister VeenVeenaa SharmaSharma foforr mentamentall support.support.
ThanksThanks ttoo alalll mmyy colleaguescolleagues iinn IIlITT KanpuKanpurr whwhoo helpehelpedd anandd encouragedencouraged mmee ttoo pursupursuee higherhigher educationeducation.. I alsalsoo extendextend thankthankss toto mmyy brothebrotherr Jeetendra,Jeetendra, whwhoo wawass alwaysalways availablavailablee ttoo helhelpp me.me.
ThanksThanks ttoo mmyy wifwifee ShachiShachi forfor mentamentall encouragement.encouragement. I amam foreverforever gratefugratefull toto allall ooff thethe instructorsinstructors whwhoo havhavee guidedguided mmyy wawayy durinduringg mmyy studiesstudies anandd ttoo ththee MetallurgicaMetallurgicall EngineeringEngineering
DepartmentDepartment.. CHAPTERCHAPTER 1
INTRODUCTIOINTRODUCTIONN
TnIn thithiss chapterchapter,, differendifferentt aspectaspectss ofof leachinleachingg ooff chalcopyritchalcopyritee or oree anandd simultaneoussimultaneous electrowinninelectro winningg araree discusseddiscussed.. UsUsee ooff chloridchloridee medimediaa forfor recoveryrecovery ofof coppercopper iiss alsoalso reviewed.reviewed.
First,First, anan overvieovervieww ooff differendifferentt fundamentalsfundamentals iiss discusseddiscussed,, anandd further,further, theitheirr subsequentsubsequent applicationapplication iiss analyzed.analyzed. ConventionalConventional methodmethodss ooff recoverrecoveryy ofof coppercopper fromfrom chalcopyritechalcopyrite areare alsoalso discusseddiscussed.. AAnn overvieovervieww ooff chloridchloridee basedbased recoverrecoveryy anandd sulfatesulfate basebasedd recoverrecoveryy ooff coppercopper iiss alsalsoo discusseddiscussed.. FinallyFinally,, aann overvieovervieww ooff leachinleachingg ofof chalcopyritechalcopyrite ororee witwithh ususee ofof ironiron chloridechloridess anandd coppecopperr chloridechloridess iiss discussed.discussed.
1.11.1 OvervieOvervieww ooff fundamentalfundamental ooff metametall leachingleaching
LeachingLeaching cacann bbee defineddefined asas a techniqutechniquee bbyy whicwhichh removaremovall ofof materiamateriall cacann bbee donedone byby dissolvindissolvingg iitt awayaway fromfrom solidssolids.. IInn conventionalconventional leachinleachingg [3],[3], ththee solidsolid iiss generallgenerallyy a stationarystationary heaheapp oror pilpilee ooff ororee anandd solutionsolution percolatepercolatess througthroughh ththee solid.solid. SolventSolvent andand solisolidd areare mixemixedd andand allowedallowed ttoo attaiattainn equilibriumequilibrium,, anandd twtwoo phasephasess areare separated.separated. IInn thethe cascasee ofof leachingleaching ooff chalcopyritechalcopyrite,, leachinleachingg resultresultss iinn a copper-bearincopper-bearingg solutionsolution.. NextNext,, ththee coppercopper ionsions frofromm ththee copper-bearincopper-bearingg solutiosolutionn areare extracteextractedd usinusingg aann organiorganicc extractantextractant,, whicwhichh isis dissolvedissolvedd iinn aann organiorganicc solvent.solvent. ThThee mosmostt commonlcommonlyy useusedd extractanextractantt isis hydroxyphenyhydroxyphenyll oximeoxime
[4][4].. IInn thithiss step,step, twtwoo differendifferentt phasephasess (organi(organicc anandd aqueous)aqueous) araree formedformed sincesince ththee organicorganic 2 phasephase,, whicwhichh containscontains thethe extractantextractant isis nonpolarnonpolar andand thethe aqueousaqueous phasphasee isis polarpolar.. TheThe coppercopper ionsions iinn ththee aqueousaqueous phasephase willwill attachattach ttoo ththee extractant,extractant, therebtherebyy loadingloading ththee extractant.extractant. AA phasphasee separationseparation betweebetweenn aqueousaqueous andand organicorganic phasephase occursoccurs next.next. TheThe aqueousaqueous phasephase isis strippedstripped ofof coppercopper ions,ions, andand iitt isis calledcalled raffinateraffinate.. TheThe raffinateraffinate iiss sentsent bacbackk toto thethe leachingleaching process.process. CopperCopper inin thethe loadedloaded organicorganic mediumediumm isis strippedstripped intointo lealeann electrolyteelectrolyte toto makemake itit richrich electrolyte.electrolyte. LastlyLastly,, coppercopper inin ricrichh electrolyteelectrolyte isis convertedconverted ttoo elementalelemental coppercopper byby electrowinningelectrowinning andand thethe resultingresulting leanlean electrolyteelectrolyte iiss sentsent bacbackk toto ththee procesprocesss toto replenisreplenishh thethe coppecopperr [4].[4]. ThThee extractionextraction andand strippingstripping ofof coppercopper fromfrom solutionssolutions witwithh oximeoxime solventsolvent extractanextractantt cancan bbee expressedexpressed asas equationequation [1.1][1.1] andand [1.2].[1.2].
2+ + Loading:Loading: 2RH(org) + Cu (aq)
+ 2+ Stripping:Stripping: R22Cu(orCU(org)g) + 2H+2H H^ 2RH(org)2RH(org) + Cu + (aq)(aq ) [1.2][1.2]
1.21.2 OverviewOverview ofof fundamentalfundamental ofof metalmetal electrowinningelectrowinning
ElectrowinninElectrowinningg cancan bbee defineddefined asas processprocess ofof removingremoving a metalmetal fromfrom solutionsolution electrolyticallelectrolyticallyy [3].[3]. WheWhenn metalmetal bearingbearing solutionsolution isis kepkeptt insideinside ththee electrochemicalelectrochemical cellcell undeunderr appliedapplied voltage,voltage, positivpositivee metametall ionionss attractattract towardtoward thethe cathodecathode andand areare reducedreduced intointo elementalelemental metalmetal.. InIn ththee cascasee ofof coppercopper electrowinning,electrowinning, purepure metalmetal isis collectedcollected onon ththee cathode.cathode.
TToo countecounterr balancebalance ththee electronselectrons forfor wholwholee system,system, anotheranother reaction,reaction, oxidation,oxidation, occursoccurs onon thethe anode.anode. AAss mosmostt ofof electrowinningelectrowinning occursoccurs onon aqueousaqueous mediamedia,, typicaltypical oxidationoxidation reactioreactionn isis hydrolysihydrolysiss ooff waterwater [3].[3]. TheThe twotwo half-celhalf-celll reactionreactionss cancan bbee writtewrittenn asas equationequation [1.3][1.3] andand [1.4].[1.4].
Mn+ + ne" + 2H20 «-> 02 + 4H + 4e~ [1.4][1.4] NeNett reactionreaction cancan bebe writtewrittenn aass equationequation [1.5].[1.5]. n+ + 4M + 2nH20 n02 + 4nH + 4M [[1.5 1.5]] ElectrowinningElectrowinning cancan bbee understoounderstoodd byby thethe diagramdiagram shownshown inin FigureFigure 1.1.1.1, Anode(+) ~ H,O FigurFiguree 1.1:1.1: SchematicSchematic diagramdiagram ofof thethe coppecopperr electrowinningelectrowinning process.process. 4 NoN oww considerconsider ththee followinfollowingg electrochemicalelectrochemical reactionreaction,, writtewrittenn aass equatioequationn [1.6]:[1.6]: Xp+ + ne- X m+ [1.6][1.6] ThThee associatedassociated electrochemicaelectrochemicall ratratee ofof reactioreactionn cacann bbee writtewrittenn aass equatioequationn [1.7][1.7] FE (\- UsinUsingg transitiotransitionn statstatee theortheoryy fromfrom chemicachemicall kinetickineticss iitt isis possiblpossiblee ttoo relaterelate thethe frefreee energieenergiess ofof activatioactivationn ttoo ththee ratratee constantsconstants kkbb oorr kfkf.. TheseThese araree predictepredictedd bbyy equatioequationn [1.8].[1.8]. kf=kbexp(-*%T) [1.8][1.8] kkbb anandd kkaa araree backwarbackwardd andand forwarforwardd reactioreactionn constantsconstants;; ¢ m+ p+ araree bulbulkk concentrationconcentration ooff speciesspecies X + anandd XP+; ; z iiss numbenumberr ofof electronelectronss transferretransferredd iinn thethe ratratee limitinlimitingg stepstep;; F iiss FaradaFaradayy constant;constant; E iiss electrochemicaelectrochemicall potentialpotential;; R iiss universauniversall gasgas constant,constant, A~GG iiss energenergyy ooff activationactivation anandd T iiss temperaturetemperature.. ThThee tertermm ¢ reflects reflect thes th sensitivitye sensitivit y ooff thethe transitiotransitionn statstatee ttoo ththee appliedapplied voltagevoltage.. IIff ¢ ThiThiss reactioreactionn provideprovidess currencurrentt densitdensityy foforr ononee half-celhalf-celll reaction.reaction. CompleteComplete electrochemicalelectrochemical reactionreactionss involvininvolvingg aatt leasleastt twtwoo halhalff celcelll reactionreactionss cacann bbee writtewrittenn asas equationequation [1.9].[1.9]. 5 Xp+ + Ym+ Xm+ + Yp+ [1.9][1.9] ThThee cathodicathodicc reactioreactionn currencurrentt densitdensityy ofof ththee half-celhalf-celll reactioreactionn musmustt bbee equaequall ttoo thethe oppositoppositee ofof ththee reactioreactionn thathatt occursoccurs anodicallyanodically [3].[3]. FoForr mormoree thathann ononee anodianodicc anandd cathodiccathodic reaction,, ththee sumsum ooff cathodicathodicc currentcurrentss balancebalancess ththee sumsum ofof anodianodicc currents.currents. ThiThiss relationshiprelationship cacann bbee writtewrittenn aass equationequation [1.10].[1.10]. Sr. ii cacathodithodic = "S-r. i i anodianodicc [1.10][1.10] AAtt equilibriumequilibrium thertheree iiss nnoo nenett flowflow ooff electrons,, eveneven thougthoughh forwardforward anandd backwarbackwardd reactionsreactions stillstill occur.occur. TheThe currencurrentt densitdensityy ooff thithiss equilibriuequilibriumm electroelectronn exchangeexchange procesprocesss iiss knowknownn asas thethe equilibriumequilibrium exchangexchangee currentcurrent densitdensityy (io(io) anandd expresseexpressedd asas equationequation [1.11].[1.11]. FE . k ( HenceHence,, ththee electrochemicalelectrochemical raterate ofof reactioreactionn cacann bbee writtewrittenn asas equationequation [1.12].[1.12]. i = i. [[1.12 1.12]] wherwheree 11n isis overpotential.overpotential. InIn ththee casecase ofof electrowinningelectro winning,, voltagvoltagee iiss applieappliedd bbyy aann externaexternall source.source. ThThee voltagvoltagee iiss a functiofunctionn ofof solutionsolution andand interfacialinterfacial resistances,, currencurrentt aanndd overaloveralll area.. ItIt isis alsalsoo a functionfunction 6 ooff temperaturetemperature.. InIn thithiss procesprocesss ththee systemsystem iiss forceforcedd ttoo ggoo backwarbackwardd bbyy aann applieappliedd voltage,voltage, ratheratherr thathann freefree energy.. ThThee applieappliedd voltagvoltagee cacann bbee expressedexpressed asas equationequation [1.13].[1.13]. ~ V applied = ~ V half cells + ~ V cathodic overpotential + ~ V anodic overpotential + IR solution + IRother [1.13] ThisThis appliedapplied voltagvoltagee iiss relaterelatedd ttoo ththee ratratee ooff electrowinningelectrowinning.. FigureFigure 1.21.2 representrepresentss completecomplete detaildetailss ooff allall procesprocesss anandd relaterelatedd electrochemicalelectrochemical potentialspotentials.. IIff severaseverall reactionsreactions taktakee placeplace simultaneouslysimultaneously aatt ththee electrode,electrode, a partiapartiall electrodelectrodee currencurrentt densitdensityy jjkk cancan bbee assignedassigned ttoo eacheach individuaindividuall reactionreaction.. ThThee partiapartiall currentcurrent densitydensity dependdependss oonn ththee stoichiometrystoichiometry ofof ththee reactionreaction anandd oonn ththee amountamount ooff substancsubstancee ooff X reactinreactingg (pe(perr uniunitt timtimee anandd peperr uniunitt electrodelectrodee areaarea)) inin ththee reactioreactionn consideredconsidered.. ThThee theoreticatheoreticall currentcurrent efficiencefficiencyy ofof reactionreaction,, Ek,Ek, isis definedefinedd asas thethe ratiratioo ooff jjkk ttoo ththee totatotall currencurrentt densitdensityy aass equationequation [1.14].[1.14]. Current efficiency = >1:: jj [1.14][1.14] wherwheree k iiss indiceindicess forfor individualindividual componencomponentt anandd iitt isis summesummedd overover numbenumberr totatotall components. 1.31.3 OverviewOverview ooff conventionalconventional chalcopyritchalcopyritee processingprocessing IInn general,, conventionalconventional chalcopyritchalcopyritee processinprocessingg cacann bbee dividedividedd intintoo twtwoo categories:categories: pyrometallurgicapyrometallurgicall anandd hydrometallurgicahydrometallurgicall methodmethodss [5].[5]. InIn pyrometallurgicapyrometallurgicall coppercopper extractioextractionn frofromm chalcopyritechalcopyrite,, ththee ororee iiss firsfirstt crushedcrushed anandd groungroundd ttoo ththee requirerequiredd size.size. ThenThen, 7 :I -- --- l------ ______L~~ : ' ~O[ ~verpotenti~ Ll.Vap p Ii ed Potential Ll.Vh alf cells ______~ _____ l __ I Ll.V cathodic overpotential -----1------ log Iii log IiI...... I e e C u 'OWllUW\O"e- FigureFigure 1.2:1.2: SchematiSchematicc diagradiagramm ooff relationshirelationshipp betweebetweenn logarithlogarithmm ofof currentcurrent densitydensity andand electrowinninelectrowinningg potential.potential. 8 chalcopyritechalcopyrite inin ththee crushecrushedd anandd groundground ororee iiss concentratedconcentrated bbyy flotation.flotation. DuringDuring flotation,flotation, crushecrushedd anandd groundground oreore iiss mixemixedd witwithh a suitablesuitable collectorcollector.. ThisThis collectocollectorr consistsconsists mostlymostly ofof ofof xanthatesxanthates,, whicwhichh araree introduceintroducedd iinn ththee slurryslurry containingcontaining ththee oreore particlesparticles.. ThThee collectorcollector absorbabsorbss oonn chalcopyritchalcopyritee particleparticless anandd iinn turntum,, ththee surfacsurfacee ofof chalcopyritchalcopyritee particleparticless becomesbecomes hydrophobichydrophobic.. AiAirr iiss thethenn passepassedd fromfrom ththee bottobottomm ooff ththee tantankk througthroughh ththee slurry.slurry. TheThe hydrophobihydrophobicc particleparticless ofof collectocollectorr coatecoatedd chalcopyritechalcopyrite thethenn attachattach ttoo aiairr bubblebubbless ttoo produceproduce froth, whicwhichh iiss collectecollectedd aatt ththee surfacsurfacee ooff ththee slurry.slurry. TheThe coppecopperr concentratconcentratee isis thethenn smeltedsmelted iinn a furnacefurnace aatt 1250°C1250°C ttoo removremovee ththee sulfursulfur anandd iroironn bbyy oxidizingoxidizing iitt witwithh oxygenoxygen [7].[7]. SulfurSulfur dioxiddioxidee andand iroironn oxidoxidee araree formeformedd aass a resulresultt ofof ththee oxygenoxygen exposure.exposure. BByy removinremovingg sulfursulfur anandd iroironn iinn ththee mattmattee makinmakingg processprocess,, coppecopperr mattmattee containincontainingg 50-70%50-70% CuCu iiss obtaineobtainedd [7][7].. ThThee sulfursulfur dioxiddioxidee iiss typicalltypicallyy convertedconverted ttoo sulfurisulfuricc acidacid inin anan acidacid plantplant andand ththee iroironn oxideoxide isis usuallusuallyy absorbeabsorbedd intintoo slagslag anandd discarded.discarded. ThisThis coppercopper mattmattee thenthen undergoesundergoes a convertingconverting stepstep ttoo removremovee ththee remaininremainingg sulfursulfur andand iron.iron. TheThe convertingconverting processprocess taketakess placeplace atat approximatelyapproximately 1250°C1250°C bbyy blowinblowingg oxygeoxygenn throughthrough coppecopperr mattematte.. ThisThis procesprocesss resultresultss iinn a relativelrelativelyy purpuree coppecopperr metalmetal,, calledcalled blisteblisterr coppercopper,, whicwhichh containscontains aboutabout 98.5%98.5% coppercopper [8].[8]. ThiThiss blisteblisterr coppecopperr iiss thethenn furtherfurther refinerefinedd pyrometallurgicallpyrometallurgicallyy iinn anan anodeanode furnacfurnacee followedfollowed bbyy electrorefininelectrorefiningg iinn a tantankk houshousee ttoo obtainobtain highighh puritpurityy electrolytielectrolyticc gradgradee coppercopper (approximatel(approximatelyy 99.9999.99%% Cu).Cu). 1.41.4 OverviewOverview ofof sulfatesulfate basebasedd andand chloridchloridee basebasedd mediamedia foforr coppercopper electrowinningelectrowinning CoppeCopperr electroelectrowinnin winningg fromfrom sulfatesulfate basebasedd aqueousaqueous medimediaa iiss thethe traditionaltraditional andand commoncommon methodmethod foforr conventionaconventionall electrowinningelectrowinning [9].[9]. HerHeree reductioreductionn ooff cupricupricc ionion taketakess placplacee onon a cathodecathode,, consumingconsuming twtwoo electronelectronss peperr ion.ion. ThisThis methomethodd ooff clectrowinningelectrowinning produceproducess a flatflat 9 cathodcathodee sheetsheet asas showshownn inin FigureFigure 1.3.1.3. BecausBecausee ooff thithiss characteristic,, thithiss sheesheett cancan bbee easilyeasily removeremovedd frofromm ththee cathodecathode.. OOnn ththee otherother hand,hand, electrodepositselectrodeposits produceproducedd frofromm chloridchloridee mediamedia tentendd ttoo bbee granulargranular.. HenceHence iitt iiss difficuldifficultt ttoo utilizutilizee traditionatraditionall sheetsheet harvestinharvestingg equipmentequipment forfor halidehalide basebasedd electrowinningelectrowinning ofof copper.copper. SulfateSulfate basebasedd chalcopyritchalcopyritee leachinleachingg isis ververyy slosloww duedue ttoo passivpassivee layelayerr formationformation onon thethe mineraminerall surfacsurfacee [10].[10]. However,, iitt hahass beebeenn shownshown thathatt chalcopyritchalcopyritee leachinleachingg iinn halidhalidee mediamedia isis relativelrelativelyy fastefasterr [1 ,, 2,, anandd 11].11]. AnotheAnotherr advantageadvantage ooff chloridechloride basebasedd leachinleachingg iiss reducedreduced electronelectron consumption.. CopperCopper metametall depositdepositss duduee toto reductioreductionn ooff cuproucuprouss ioionn inin ththee cascasee ofof halidhalidee basedbased mediumediumm electrowinning.electrowinning. ThuThuss reductioreductionn ooff coppecopperr iinn halidhalidee mediumediumm consumesconsumes oneone electroelectronn peperr molmolee ooff CCuu iinn contrastcontrast ttoo twtwoo electronelectronss peperr molemole ofof coppecopperr whewhenn reducedreduced fromfrom sulfatesulfate medium.. Consequently,, powepowerr consumptioconsumptionn foforr electrowinninelectrowinningg isis lessless thathann thatthat fromfrom sulfatsulfatee mediummedium.. InIn addition,, reductioreductionn in iroironn medimediaa reducereducess anodanodee energyenergy requirementrequirementss andand eliminateeliminatess aciacidd mistinmistingg bbyy replacinreplacingg watewaterr hydrolysihydrolysiss witwithh ferrousferrous oxidationoxidation.. c C A c A T T H T H SulfatSulfatee o0 0 ChloridChloridee D O MediaMedia D MediaMedia E E AfteAfterr HarvestingHarvesting III III ~ II~· P. III ~ CathodeCathode GranulaGranularr SheeSheett ElectrodepositsElectrodeposits FigureFigure 1.3:1.3: ComparisonComparison ooff electrodepositselectrodeposits frofromm sulfatesulfate andand chloridchloridee media.media. 1010 1.51.5 OvervieOvervieww oofleachingf leaching ofof chalcopyritechalcopyrite ororee witwithh ususee ofof ironiron chloridechloridess anandd coppercopper chlorideschlorides FerriFerricc anandd cupricupricc chloridchloridee solutionssolutions areare ververyy effectiveffectivee oxidizinoxidizingg agentagentss foforr leachinleachingg ofof sulfidesulfide mineralsminerals.. ThThee CLEARCLEAR procesprocesss utilizeutilizess a methomethodd ofof directdirect treatmentreatmentt ooff coppercopper concentrateconcentratess witwithh thesthesee twtwoo solutionsolutionss [4].[4]. TherTheree areare twtwoo stagestagess ofof leachingleaching iinn a lixiviantlixiviant containincontainingg sodiusodiumm chloridechloride,, ironiron chlorideschlorides,, anandd coppecopperr chlorides.chlorides. TheThe firstfirst stagstagee leach,leach, anan oxidatiooxidationn stage,stage, iiss essentiallyessentially witwithh ferricferric chloride,chloride, whicwhichh woulwouldd follofolloww ththee mechanismechanismm asas expresseexpressedd aass equatioequationn [1.15].[1.15]. CuFeS2+CuFeS2+ 4FeCl4FeCh3 -----+-> CuChCuCl2 + 5 FeChFeCl2 + 2So2S° [[1.15 1.15]] TheThe secondsecond leachingleaching stage,stage, a reductioreductionn stage,stage, useusess chalcopyritechalcopyrite ttoo reacreactt witwithh cupricupricc chloride,chloride, expressedexpressed aass equatioequationn [1.16].[1.16]. CuFeS2+CuFeS2+3CuCl 3CuCh2 ------+» 4CuC4CuCIl + FeChFeCl2 + 2S2So° [[1.16 1.16]] SodiumSodium chloridechloride iiss addeaddedd ttoo keekeepp cuprouscuprous chloridechloride inin solution.solution. ThThee solutionsolution iiss electrolyzedelectrolyzed inin a diaphragmdiaphragm cellcell wherewhere halfhalf ofof thethe coppercopper isis depositeddeposited cathodicallycathodically andand thethe remainingremaining solutionsolution isis oxidizedoxidized atat anan insolublinsolublee anode.anode. HerHeree electrowinningelectrowinning iiss a low-energlow-energyy stepstep becausebecause thethe anodanodee oxidizeoxidizess CuCICuCl ttoo CuChCuCl2 whilwhilee ththee cathodecathode reducereducess CuCICuCl ttoo metametall aatt a ververyy lowlow cellcell potentialpotential.. AccordingAccording ttoo studystudy shownshown bbyy HiratHiratoo etet al.al. [1-2][1-2] leachinleachingg ooff chalcopyritchalcopyritee exhibitexhibitss halfhalf ordeorderr dependencydependency oonn FeCFeClb3 concentrationconcentration anandd itit isis independentindependent ofof FeClFeCh2 concentrationconcentration.. InIn additionaddition,, changchangee iinn mixemixedd potentiapotentiall wawass onlonlyy observedobserved duedue toto changechange inin concentratioconcentrationn ofof 1111 FeCl3FeCb.. OOnn thethe otherother hand,hand, a studstudyy showshownn bbyy HiratoHirato etet al.al. [1-2][1-2] concludeconcludess thathatt ththee leachingleaching ofof chalcopyritechalcopyrite withwith CuChCuC^ followsfollows linealinearr kinetickineticss oveoverr aann extendeextendedd periodperiod,, followedfollowed bbyy anan acceleratioaccelerationn stagestage,, asas a resulresultt ofof aann increaseincrease iinn ththee reactioreactionn surfacesurface area.area. ThThee leachinleachingg ratratee ofof chalcopyritchalcopyritee wawass proportionaproportionall ttoo [CUCh]O.5,[Q1CI2]0'5, whereawhereass iitt wawass inverselinverselyy proportionaproportionall toto [CuCI]05.[CuCl]05. BotBothh reactionreaction 1 anandd 2 suggestsuggest thathatt leachinleachingg kinetickineticss dependsdepends oonn cupricupricc ioionn toto cuprouscuprous ionion ratiratioo aass welwelll asas ferricferric ioionn ttoo ferrousferrous ioionn ratioratio;; howevehoweverr ththee exacexactt mechanismechanismm ofof reactionreaction,, iinn presencpresencee ofof allall species,species, iiss nonott knowknownn ttoo datedate.. HencHencee aann experimentexperiment matrimatrixx isis designedesignedd ttoo studystudy ththee effecteffect ooff botbothh ironiron anandd coppecopperr chloridchloridee foforr examinatioexaminationn ofof a possiblepossible optimuoptimumm outputoutput.. InIn additionaddition,, leachinleachingg kinetickineticss foforr ororee inin ththee presencpresencee ofof thesthesee speciesspecies iiss alsoalso a subjectsubject ofof discussiondiscussion inin thisthis piecepiece ofof research.research. IInn industry,industry, leachingleaching processeprocessess cancan taktakee placplacee iinn heapsheaps,, dumpdumpss oorr vesselsvessels.. IInn heapheap leachinleachingg processeprocessess ththee solisolidd particleparticless areare depositedepositedd oonn sloped,sloped, essentiallessentiallyy imperviouimperviouss padspads.. AA leachinleachingg solutionsolution isis sprayedsprayed oror drippedrippedd onon totopp ofof ththee heapheap,, andand ththee solutiosolutionn graduallygradually percolatepercolatess througthroughh ththee bebedd dowdownn ttoo ththee imperviouimperviouss pad.pad. ThThee loadeloadedd oorr "pregnant""pregnant" leachleach solutionsolution iiss sentsent ttoo a recoverrecoveryy step.step. IInn ththee cascasee ofof columcolumnn leaching,leaching, solisolidd particleparticless areare placedplaced insidinsidee a cylindricalcylindrical columncolumn andand leachinleachingg solutionsolution iiss circulatecirculatedd iinn ththee columncolumn.. ThisThis solutiosolutionn isis thethenn sentsent toto ththee recoverrecoveryy step.step. InIn ourour casecase,, closeclosedd looloopp columcolumnn leachinleachingg wawass chosechosenn foforr somesome ooff thethe experiments.experiments. TheThe closedclosed looloopp naturnaturee ooff combinecombinedd columcolumnn leachinleachingg withwith electrowinningelectrowinning procesprocesss cancan makmakee a contributioncontribution towardtowardss addressinaddressingg environmentaenvironmentall issuesissues forfor suchsuch processingprocessing.. ThThee leachinleachingg andand electrowinningelectrowinning conditionsconditions areare examinedexamined separatelseparatelyy byby conductingconducting factoriafactoriall desigdesignn ofof experimentexperimentss iinn nexnextt section.section. CHAPTERCHAPTER 2 EXPERIMENTEXPERIMENTA ALL PROCEEDURESPROCEEDURES IInn thithiss chaptechapterr electrolyteelectrolyte composition,composition, columncolumn design,design, instrumentation,instrumentation, electrochemicalelectrochemical cellcell andand experimentaexperimentall procedureproceduress areare discussed.discussed. TheThe chemicalschemicals useusedd forfor thisthis studystudy areare listedlisted alonalongg withwith informatioinformationn regardinregardingg ththee associatedassociated sourcesource andand puritypurity.. ElectrochemicalElectrochemical cellscells andand otherother instrumentinstrument areare alsalsoo discussed.discussed. Lastly,Lastly, allall ofof experimentalexperimental proceduresprocedures usedused inin thisthis studystudy areare discussediscussedd inin thisthis chapter.chapter. 2.2.11 ListList ofof chemicalschemicals usedused CupricCupric chloridechloride dihydratedihydrate (CuCb.2H(CuCl2.2H220,0, MW~170.48MW~ 170.48,, puritpurityy 99%)99%) waswas obtainedobtained fromfrom EMEMDD chemicals.chemicals. SodiumSodium chloridechloride (NaCI,(NaCl, MWMW ~ 58.44,58.44, 99%99% purity)purity),, calciumcalcium chloridechloride (CaCl(CaCb,2, MMWW ~1l0.98,-110.98, 99%99% purity)purity),, nitricnitric acidacid (HN03,(HNO3, MWMW ~ 63.01,63.01, assayassay 68-70%)68-70%) andand cuproucuprouss chloridechloride (CuCI,(CuCl, MMWW ~ 99.00,99.00, puritpurityy 90%)90%) werewere obtainedobtained fromfrom MallinckrodtMallinckrodt ChemicalsChemicals., ferricferric chloridechloride anhydrousanhydrous ( FeCh,FeCl3, MWMW ~ 162.21,162.21, puritypurity 98%98%)) waswas obtainedobtained fromfrom AcroAcross Chemicals.Chemicals. FerrousFerrous chloridechloride tetrtetraa hydrathydratee (FeCb.4H(FeCl2.4H220,0, MW~198.81MW~198.81,, puritypurity 99%)99%) waswas obtaineobtainedd fromfrom FisheFisherr Scientific.Scientific. HydrochloriHydrochloricc acidacid (HCI,(HC1, MMWW ~ 36.46,36.46, assayassay 36.5-38%)36.5-38%) waswas obtaineobtainedd frofromm EMDEMD Chemicals.Chemicals. AlAlll ofof thesthesee chemicalschemicals werweree usedused withoutwithout anyany furtherfurther purificationpurification.. AlAlll ofof ththee solutionssolutions werweree preparepreparedd usingusing ASTASTMM TypeType I water.water. 1313 2.22.2 LeachantLeachant compositioncomposition IInn mosmostt ofof ththee experimentsexperiments,, thethe compositiocompositionn ofof leachantleachant anandd electrolyteelectrolyte wawass keptkept constantconstant forfor leachingleaching andand electrowinning.electrowinning. TheThe maimainn sourcesource ofof coppecopperr durinduringg experimentexperimentss waswas cuprouscuprous chloride,chloride, bubutt foforr completecomplete examinationexamination ooff combinedcombined leachinleachingg anandd electrowinningelectrowinning iroironn chloridechloride andand cupriccupric chloridchloridee werweree used.used. AAss solubilitysolubility ooff CuCCuCll iinn watewaterr iiss ververyy low,low, anan indifferenindifferentt salt,salt, sodiumsodium chloridechloride,, wawass alsalsoo addeaddedd iinn somsomee experimentsexperiments.. NaCNaCIl doesdoes nonott causecause anyany precipitatioprecipitationn ooff ththee coppercopper frofromm solution,solution, althoughalthough ititss presencpresencee increaseincreasess ththee ionicionic strengthstrength ooff solutionsolution.. AlAlll experimentexperimentss werweree performeperformedd usinusingg hydrochlorihydrochloricc aciacidd whicwhichh alsoalso increasesincreases solubilitysolubility ofof cuproucuprouss ions.ions. 2.2.33 ElectrochemicaElectrochemicall celcelll anandd InstrumentationInstrumentation AllAll electrodepositioelectrodcpositionn experimentsexperiments werweree performeperformedd usinusingg a twtwoo electrodelectrodee celcelll consistinconsistingg ofof a leadlead anodeanode andand stainlessstainless steelsteel workingworking electrodeelectrode (Cathode).(Cathode). ForFor combinedcombined leachingleaching andand electrowinning,electrowinning, a platinuplatinumm mesmeshh electrodeelectrode wawass chosechosenn aass ththee countecounterr electrodelectrodee (anode).(anode). ForFor potentiodynamipotentiodynamicc experimentsexperiments stainlessstainless steelsteel electrodeselectrodes (working)(working),, lealeadd countercounter electrodes,electrodes, anandd saturatedsaturated calomecalomell referencreferencee electrodeselectrodes werweree chosen.chosen. ThThee referencreferencee electrodelectrodee isis anan AccumeAccumett ElectrodElectrodee fromfrom FisheFisherr Scientific.Scientific. ThThee platinuplatinumm countecounterr electrodelectrodee wawass obtainedobtained fromfrom BeckmaBeckmann instruments.instruments. ElectrochemicaElectrochemicall testtestss werweree conductedconducted usinusmgg a EG&GEG&G 273273 (operated(operated usinusingg PowersuitePowersuite software,software, bbyy PrincetoPrincetonn appliedapplied researchresearch)) andand a PCI4/75PCI417500 potentiostapotentiostatt (operate(operatedd usinusingg virtualvirtual front panepanell software),software), madmadee bbyy GamryGamry Instruments,Instruments, connectedconnected ttoo anan IBIBMM compatiblecompatible PPCC andand AFASAF ASRR rotatorotatorr fromfrom PinPinee Instruments.Instruments. 1414 2.2.44 ExperimentaExperimentall proceduresprocedures AlAlll ooff ththee experimentalexperimental procedureproceduress usedused iinn thithiss studystudy areare discusseddiscussed Inin detaidetaill iinn thisthis sectionsection.. TheseThese experimentalexperimental procedureproceduress areare provideprovidedd forfor columncolumn leachinleachingg experiments,experiments, factorialfactorial desigdesignn leachingleaching experiments,experiments, factorialfactorial designdesign electrodepositionelectrodeposition experiments,experiments, electroelectrowinnin winningg matrixmatrix experimentexperimentss (using(using CaClCaCh2 anandd glue)glue),, potentiodynamipotentiodynamicc scanscan experiments,experiments, andand ImagImagee analysisanalysis usinusingg PAXPAX®® Cam.Cam. 2.4.2.4.11 ColumnColumn leachinleachingg experimentsexperiments witwithh electrowinningelectrowinning A lablab scalescale experimentalexperimental setupsetup waswas establishedestablished inin orderorder toto evaluateevaluate preliminarpreliminaryy viabilityviability ofof combinedcombined leachingleaching anandd electrowinninelectrowinningg (EW(EW)) aass shownshown iinn FigurFiguree 2.12.1.. OneOne goagoall ofof thisthis researcresearchh isis toto testestt ththee feasibilitfeasibilityy ooff simultaneoussimultaneous leachingleaching anandd electrowinnningelectrowinnning.. ThereforeTherefore leachinleachingg solutionsolution (after(after passinpassingg througthroughh anan ororee columncolumn)) isis utilizeutilizedd forfor electrowinning.electrowinning. LeachinLeachingg solutionsolution wawass circulatecirculatedd fromfrom ththee EEWW tantankk througthroughh ththee columcolumnn (filled(filled withwith ore),ore), andand thethenn returnedreturned ttoo thethe EEWW tanktank.. ChemicalChemical reactioreactionn betweebetweenn ororee andand solutiosolutionn iiss responsiblresponsiblee forfor leachingleaching.. ContinuousContinuous circulatio circulationn ofof solutionsolution causecausess dissolutiodissolutionn ooff ganguganguee mineralmineral.. TheThe recirculatinrecirculatingg solutiosolutionn wawass maintainemaintainedd atat a sesett ppHH bbyy a ppHH controllercontroller.. EEhh anandd ppHH ofof thethe solutionsolution werweree continuouslycontinuously monitoredmonitored.. ElectrowonElectrowon coppecopperr wawass measuremeasuredd bbyy weighweightt inin regularegularr intervals.intervals. StainlessStainless steelsteel electrodeselectrodes werweree useusedd aass ththee workinworkingg electrodeselectrodes.. PlatinumPlatinum mesmeshh electrodelectrodee wawass chosechosenn aass ththee countercounter electrodeelectrode.. ElectrowinninElectrowinningg operationoperation wawass carriedcarried ououtt iinn galvanostatigalvanostaticc modemode atat 5 mArnA.. SolutionSolution fromfrom a glasglasss reservoireservoirr wawass circulatedcirculated throughthrough ththee ororee columncolumn,, whicwhichh iiss designeddesigned inin suchsuch mannermanner thathatt onlonlyy solutiosolutionn cancan paspasss througthroughh ththee oreore andand itit shouldshould notnot flowflow bacbackk towardtowardss ththee pumpumpp side.side. TToo ensurensuree appropriatappropriatee flowflow adequateadequate glassglass beadbeadss andand plastiplasticc mesmeshh werweree used.used. 1515 Hel to ma n pH FigurFiguree 2.12.1:: A schematicschematic diagramdiagram showingshowing columncolumn leachinleachingg operationoperation andand electrowinning,electrowinning, simultaneously.simultaneously. TheThe arrowsarrows showshow ththee directiondirection ofof flowflow ofof leachingleaching solution.solution. 1616 AlAlll experimentexperimentss werweree carriecarriedd ououtt atat roomroom temperaturetemperature.. ConsumptionConsumption ofof acidacid (HCI)(HC1) waswas monitoremonitoredd andand dayday ttoo dayday consumptioconsumptionn wawass recordedrecorded.. RegulaRegularr monitorinmonitoringg ofof electrodepositeelectrodepositedd coppecopperr wawass alsalsoo performedperformed.. ThThee leachinleachingg solutiosolutionn compositioncomposition iiss specifiedspecified iinn TablTablee 2.12.1.. 2.4.22.4.2 FactoriaFactoriall desigdesignn columcolumnn leachinleachingg experimentsexperiments IInn orderorder ttoo explorexploree ththee effecteffect ofof individuaindividuall componentscomponents liklikee acidacid concentration,concentration, concentratioconcentrationn ofof ferricferric andand ferrousferrous ionion,, concentrationconcentration ooff cupricupricc anandd cuproucuprouss ionion,, a factorialfactorial designdesign ofof experimentsexperiments wawass establishedestablished.. FactoriaFactoriall experimentexperimentss allowallow uuss toto studystudy ththee effecteffect ofof eacheach factofactorr onon ththee responsresponsee variablevariable,, asas welwelll aass effectseffects ofof interactioninteractionss betweebetweenn individualindividual factorsfactors onon ththee responsresponsee variable.variable. FactorFactorss chosenchosen inin thithiss cascasee araree effeceffectt ofof individualindividual componentcomponentss (acid(acid concentrationconcentration,, ratiratioo ooff concentratioconcentrationn ofof ferricferric anandd ferrouferrouss ionion,, andand ratiratioo ofof concentratioconcentrationn ooff cupriccupric anandd cuprouscuprous ion)ion).. InIn mosmostt ooff ththee factoriafactoriall experimentsexperiments eacheach factorfactor hashas onlyonly twtwoo levellevelss (hig(highh andand low)low).. NoNoww consideconsiderr anan experimentexperiment usinusingg 3 factorfactorss AA,, BBand and C withwith TablTablee 2.12.1:: LeachinLeachingg solutiosolutionn detaildetailss forfor combinedcombined leachinleachingg andand EEWW teststests ParameteParameterr DetailDetailss ConstituentsConstituents 1.9M1.9M CaClCaCh,2, 0.10.1MM CuCh,CuCl2, MasMasss ooff oreore 500500 gramgram SizeSize ofof oreore (-14 ++ 3535)) meshmesh VolumVolumee ooff solutionsolution 10001000 mlml ppHH ooff solutionsolution 1.51.5 FloFloww raterate 2.2.88 liter/hourliter/hour 1717 2 levellevelss (high(high andand low).. ThisThis willwill resulresultt inin 8 treatmenttreatment combinations.combinations. A setset ofof teststests thatthat follofolloww factoriafactoriall desigdesignn approachapproach witwithh variablevariabless AA,, BBand and C testetestedd atat highighh (+(+)) andand loloww ((--) levellevelss iiss presentepresentedd iinn TableTable 2.2.. TheThe valuvaluee ofof maimainn effeceffectt parameteparameterr andand interactiointeractionn effecteffect parameteparameterr isis indicativindicativee ofof hohoww strongstrong individualindividual factorfactor affectsaffects ththee responsresponsee variable.. ThThee nullnull outcomeoutcome indicateindicatess ththee neutralitneutralityy ofof effecteffect parameterparameter.. ThThee relativerelative effectseffects ofof ththee parameparameterterss areare shownshown below:below: (A) = (-Yi+ Y2 -Y3 +Y4 -Y5 + Y6 -Y7 +Y8)/8 (B) = (-Y1-Y2 +Y3 +Y4 -Y5 -Y6 +Y7 +Y8)/8 (C) = (-Y,- Y2 -Y3 -Y4 +Y5 + Y6 +Y7 +Y8)/8 TablTablee 2.22.2:: Three-factoThree-factorr desigdesignn ooff experimentsexperiments aatt hhigighh andand loloww levelslevels RuRunn A B C AABB AACC BBCC ABABCC ObservationObservation "11 - - - + + + - Y,Yj 2 + - - - - + + YY22 3 - + - - + - + YY33 4 + + - + - - + YY44 5 -- + + -- + YYs5 6 + - + - + - - YY66 7 - + + -- + - YY77 8 + + + + + + + YsY8 1818 (AB) = (Yi+ Y2 - Y3 -Y4 -Y5 -Y6 + Y7 +Y8)/8 (AC) = (Yi-Y2 +Y3 -Y4 - Y5 - Y6 -Y7 +Y8)/8 (BC) = (Yi+ Y2 - Y3 -Y4 - Y5 - Y6 +Y7 +Y8)/8 (ABC) = (-Yi+ Y2 +Y3 -Y4 +Y5 -Y6 - Y7 +Y8)/8 Mean = (Yi+ Y2 +Y3 +Y4 +Y5 + Y6 +Y7 +Y8)/8 ChalcopyritChalcopyritee oreore ooff sizesize (-3(-355 +100+100)) wawass taketakenn anandd wewett screenedscreened properlproperlyy foforr removaremovall ofof finesfines.. OrOree wawass thethenn driedriedd foforr furthefurtherr use.. A smallsmall 5050 mmll burettburettee wawass useusedd foforr leaching.leaching. LeachinLeachingg solutionsolution fromfrom thethe reservoireservoirr iiss pumpepumpedd intointo ththee burettburettee wherwheree iitt fluidizefluidizedd oreore particlesparticles.. ThiThiss fluidfluid iiss sensentt bacbackk toto ththee reservoirreservoir.. ThisThis operationoperation iiss carriecarriedd outout forfor a perioperiodd ofof twtwoo daysdays.. A schematicschematic diagramdiagram foforr ththee leachinleachingg setupsetup inin smallsmall columncolumnss isis shownshown iinn FigureFigure 2.22.2.. ParametersParameters:: SizSizee ooff oreore -35-35 ++10 1000 meshmesh TimTimee ofof leachingleaching 2 daysdays MasMasss ofof oreore 5 gramgram VolumVolumee ooff leachinleachingg solutionsolution 202000 mlml FlowFlow ratratee ooff solutionsolution 2.2.88 LlhourL/hour 1919 Small Column II Glass Chamber Leaching solution J..",o.--- FigureFigure 2.22.2:: SchematicSchematic diagramdiagram showinshowingg leachingleaching ofof oreore inin a smallsmall columcolumnn forfor ththee timetime ooff twtwoo days.days. 2020 TheThe testestt matrimatrixx forfor eighteight experimentsexperiments isis shownshown inin TableTable 2.3.2.3. AsAs statedstated aboveabove thethe matrixmatrix isis factorialfactorial designeddesigned soso asas toto tindfind outout thethe effectseffects ofof individualindividual parametersparameters.. TheThe ratiratioo ofof cupriccupric ioionn toto cuproucuprouss ionion,, ferricferric toto ferrousferrous ion,ion, andand concentrationconcentration ofof HClHC1 areare chosenchosen asas factorsfactors andand thethe amounamountt ofof coppercopper extractedextracted (gm/gm(gm/gm ofof ore)ore) asas ththee responseresponse variablevariable.. TheThe rangerangess ofof concentrationsconcentrations werweree chosenchosen basebasedd onon anticipatedanticipated operatingoperating parametersparameters.. TheThe ppHH ofof eacheach solutionsolution wawass measuredmeasured beforbeforee andand afterafter leaching.leaching. AfterAfter completioncompletion ofof leaching,leaching, solidsolid waswas filteredfiltered outout fromfrom ththee columncolumn andand dried.dried. SolidSolid leachingleaching residueresidue wawass completelycompletely groundground andand digestedigestedd iinn aquaquaa regiaregia.. EqualEqual amountsamounts ofof solidsolid fromfrom eacheach testtest werewere digesteddigested inin aquaaqua regia,regia, diluted,diluted, andand sendsend forfor ICPMSICPMS analysis.analysis. ToTo confirmconfirm thethe resultresultss ofof columncolumn leachingleaching experimentsexperiments,, beakerbeaker testtestss werewere alsoalso performedperformed usingusing similarsimilar parameteparameterr asas useusedd forfor factorialfactorial designdesign experiments.experiments. OreOre samplesample waswas mixedmixed withwith leachingleaching solutionsolution andand stirredstirred vigorouslvigorouslyy inin a beakerbeaker forfor 1 day.day. AfterAfter completioncompletion ofof leaching,leaching, ICPMSICPMS analysisanalysis ofof digesteddigested oreore waswas performeperformedd anandd thethe resultsresults werweree useuse ttoo comparecompare witwithh columncolumn testtest results.results. 2.4.32.4.3 FactorialFactorial designdesign electrowinningelectrowinning experimentsexperiments InIn orderorder toto evaluateevaluate electrowinningelectrowinning performanceperformance,, thethe samesame solutionssolutions werewere usedused forfor bothboth electrowinningelectrowinning andand mineraminerall leaching.leaching. ThisThis isis essentialessential toto evaluateevaluate combinedcombined leachingleaching andand electrowinningelectrowinning bbyy usinusingg ththee samesame solution.solution. StainlessStainless steelsteel cathodescathodes (thickness(thickness = 0.060.06 mmmm 2 andand areaarea 2-32-3 cmcm ) werweree usedused.. CathodesCathodes andand anodesanodes werweree spacedspaced 1 cmcm apart.apart. InIn orderorder toto simulatesimulate anan actuaactuall tanktank househouse environment,environment, leadlead isis usedused asas ththee anode.anode. LeaLeadd isis resistanresistantt toto corrosion;corrosion; itit iiss anan oxygenoxygen evolvingevolving electrodeelectrode.. (Use(Use ofof reusablreusablee stainlessstainless steelsteel electrodeselectrodes establishedestablished earlierearlier inin thethe IsIsaa procesprocesss [12][12] allowsallows currentcurrent densitydensity toto bbee increasedincreased byby 10%10% overover previoupreviouss starterstarter sheetsheet technology.technology.)) TheThe volumvolumee ofof electrolyteelectrolyte forfor eacheach testtest wawass 100100 ml.ml. 2121 TableTable 2.32.3:: FactoriaFactoriall desigdesignn testtest matrixmatrix forfor leachinleachingg andand electrowinningelectrowinning TesTestt IDID CuCu++(M)++(M) CuCu+(M)+(M) FeFe+++(M)+++(M) FeFe++(M)++(M) HC1(MHCI(M)) CuOCu01-09Fe01-09H0 1-09FeO 1-09H055 0.010.01 0.090.09 0.00.011 0.00.099 0.00.055 Cu09-01Fe01-09H0Cu09-01FeOl-09H055 0.00.099 0.00.011 0.00.011 0.00.099 0.00.055 CuOl-09Fe09-01H05Cu01-09Fe09-01H05 0.00.011 0.00.099 0.00.099 0.00.011 0.00.055 Cu09-01Fe09-01H0Cu09-01Fe09-01H055 0.00.099 0.00.011 0.00.099 0.00.011 0.00.055 Cu01-09Fe01-09H1CuOl-09FeOl-09HI55 0.00.011 0.00.099 0.00.011 0.090.09 0.10.155 Cu09-01Fe01-09H1Cu09-01FeOl-09HI55 0.00.099 0.00.011 0.00.011 0.090.09 0.10.155 Cu01-09Fe09-01H1CuOl-09Fe09-01HI55 0.00.011 0.00.099 0.0 0.099 0.010.01 0.10.155 Cu09-01Fe09-01H1Cu09-0 1F e09-0 1H 155 0.00.099 0.00.011 0.00.099 0.00.011 0.10.155 ThThee chemicalchemicalss usedused foforr thesthesee experimentexperimentss include:include: 1.1. CuClCuCh.2. 2H220 22.. CuCICuCl 33.. FeClFeCh3 44.. FeCh.4HFeCl2.4H2200 55.. HCIHC1 ElectrowinninElectrowinningg operationoperationss werweree carriecarriedd ououtt atat 40°C40°C.. ThThee durationduration ooff electrowinningelectrowinning waswas 2200 hourhourss foforr eaceachh set.set. Initially,Initially, highighh currentcurrent densitydensity,, 2255 mA/cmA/cmm 2 waswas useusedd foforr a shortshort timetime (10(1000 secondsecond)) ttoo assisassistt iinn uniforuniformm depositiodepositionn foforr latelaterr timetime.. DepositioDepositionn wawass carriecarriedd outout usingusing 2 galvanostatigalvanostaticc currencurrentt aatt 5 mA/cmmA/cm . TheThe schematicschematic diagradiagramm foforr thithiss procesprocesss isis shownshown inin FigurFiguree 2.3.2.3. ThThee ratiratioo ooff cupricupricc ionion ttoo cuproucuprouss ionion,, ferriferricc ioionn ttoo ferrousferrous ioionn andand HCIHC1 concentratioconcentrationn araree chosechosenn aass factorfactorss anandd currencurrentt efficiencyefficiency asas ththee responsresponsee variable.variable. TheThe solutionsolution compositionscompositions araree providedprovided iinn TablTablee 2.32.3.. 2222 TemperaturTemperaturee ThermometerThermometer Lead anode ControllerController EWEW tantankk Lead anode SSSS cathodecathode TemperaturTemperaturee PotentiostatPotentiostat controlledcontrolled bathbath FigureFigure 2.3:2.3: SchematicSchematic diagramdiagram representingrepresenting electrowinningelectrowinning operationoperation carriedcarried outout inin a constanconstantt temperaturetemperature bath.bath. 2.4.42.4.4 ElectrowinningElectrowinning testestt matrixmatrix IIII FactorialFactorial designdesign experimentsexperiments werweree conductedconducted toto exploreexplore effectseffects ofof variouvariouss factorsfactors asas statedstated inin ththee previousprevious section.section. HoweveHoweverr toto achieveachieve goodgood cathodicathodicc coppercopper quality,, organicorganic additiveadditive isis anan essentiaessentiall constituentconstituent forfor thethe electrolyte.electrolyte. AdditiveAdditivess producproducee finefine grained,, purepure anandd attractiveattractive coppercopper electrodeposition.electrodeposition. AdditivesAdditives areare alsalsoo effectiveeffective forfor reducinreducingg dendriticdendritic growthgrowth inin cathodes.cathodes. InIn manmanyy casescases leachingleaching solutionssolutions produceproduce Jarosite.. JarositeJarosite formationformation tendstends toto decreasedecrease atat lowlow ppHH levelslevels.. Also,, lowlow pHpH levelslevels araree usuallyusually needeneededd toto extractextract metals.metals. Thus,, inin orderorder toto maintainmaintain leachingleaching andand minimizminimizee JarositJarositee formationformation iinn leachingleaching columns,columns, anan additionaladditional correspondingcorresponding setset ofof electroelectrowinnin winningg experimentsexperiments werewere conductedconducted usinusingg thethe solutionsolution configurationconfiguration shownshown iinn TableTable 2.4.. AAss solubilitysolubility ofof CuClCuCl inin watewaterr isis ververyy low,, hencehence inin thesethese experimentsexperiments calciumcalcium chloridchloridee (an(an indifferentindifferent salt)salt) wawass addedadded toto produceproduce gypsumgypsum ratheratherr thanthan 2233 jarositejarosite.. ItIt alsalsoo causescauses incrementincrement ooff ioniionicc strengthstrength ooff solution.solution. StainlessStainless steelsteel cathodecathode z2 ((thicknes((thicknesss = 0.060.06 mm)mm) andand areareaa (2-3(2-3 cm )))) werweree spacedspaced 1 cmcm apart;apart; TeflonTeflon spacerspacerss werewere useusedd foforr thithiss purpospurposee (spacing(spacing = 1 cm).cm). IInn ordeorderr ttoo simulatesimulate aann actuaactuall tantankk househouse environment,environment, leadlead isis useusedd aass ththee anode.anode. TheThe volumvolumee ooff electrolyteelectrolyte forfor eacheach sesett wawass 100100 ml.ml. ElectrowinningElectrowinning operationoperationss werweree carriecarriedd ououtt aatt 40°C40°C.. TheThe durationduration ofof electrowinningelectrowinning wawass 2020 hourhourss foforr eacheach set.set. InitiallInitiallyy highighh current,current, 22S5 mA/cmA/cmm 2 wawass useusedd initiallinitiallyy foforr a shortshort timetime (100(100 second)second) ttoo assistassist witwithh uniformuniform depositiondeposition.. DepositioDepositionn wawass carriecarriedd ououtt usinusingg galvanostaticgalvanostatic 2 currentcurrent atat S5 mA/cm .. 100100 ppppmm ooff collagencollagen glugluee wawass useusedd forfor eaceachh testtest.. ChlorideChloride saltsalt (O.lS(0.15 MM CaCb)CaC^) wawass alsoalso usedused.. HydrochloricHydrochloric aciacidd (O.lS(0.15 M)M) wawass useusedd forfor eacheach test.test. TableTable 2.42.4:: ElectrowinningElectrowinning testestt matrimatrixx IIII TestTest IDID Cu22++(M)(M) CU+(M)Cu+(M) Fe33++(M)(M) Fe22+\M)(M) I (mAlcm2)(mA/cmz) CulO-OOFeOO-0Cu 1O-OOF eOO-OO0 0.10.100 0.00.000 0.000.00 0.0 0.000 S5 Cu00-10Fe00-0CuOO-1 OF eOO-OO0 0.00.000 0.10.100 0.000.00 0.000.00 5 CuOO-1Cu00-10Fel0-0 OF e 10-00 0 0.00.000 0.10.100 0.100.10 0.000.00 5 CuOO-1Cu00-10Fe00-0 OF eOO-033 0.000.00 0.10.100 0.000.00 0.100.10 5 CuOO-10FeOO-03Cu00-10Fe00-03 0.00.000 0.10.100 0.000.00 0.030.03 5 CuOO-IOFeOO-01Cu00-10Fe00-01 0.000.00 0.10.100 0.000.00 0.010.01 5 CuOO-10Fe03-00Cu00-10Fe03-00 0.000.00 0.10.100 0.030.03 0.000.00 5 CuOO-1Cu00-10Fe01-0 OF eO 1-000 0.000.00 0.10.100 0.00.011 0.000.00 5 CuOO-10Fe05-05CuOO-10Fe05-05 0.000.00 0.10.100 0.00.055 0.00.055 5 CuOS-OSFeOS-05Cu05-05Fe05-05 0.050.05 O.OS0.05 O.OS0.05 O.OS0.05 5 Cu03Cu03-06Fe05-0 -06F eOS-OS5 0.030.03 0.070.07 0.00.055 0.050.05 5 Cu02-08FCu02-08Fe05-0 eOS-OS5 0.020.02 0.080.08 0.00.055 0.050.05 5 Cu01-09FeOS-OSCu01-09Fe05-05 0.010.01 0.090.09 0.00.055 0.050.05 5 2424 2.4.2.4.55 ImagImagee analysisanalysis ImagImagee analysianalysiss wawass carriecarriedd ououtt usinusingg a PAXCaPAXCamm digitadigitall cameracamera (model(model PXPX 5 CM)CM) atat differendifferentt magnificationsmagnifications.. ImageImage J softwaresoftware wawass useusedd ttoo determindeterminee ththee deposidepositt coveragcoveragee area.area. A BinoculaBinocularr StereoStereo ZooZoomm MicroscopMicroscopee fromfrom AmscopAmscopee wawass useusedd forfor lowerlower magnificationmagnification Images.images. AAnn AxioskoAxioskopp microscopmicroscopee frofromm ZeisZeisss wawass useusedd foforr highehigherr magnificatiomagnificationn images.images. PAX-iPAX-itt softwaresoftware wawass useusedd forfor imagimagee acquisitionacquisition anandd analysis.analysis. PercenPercentt electrodepositelectrodeposit coveragecoverage wawass calculatedcalculated usinusingg ImagImagee J softwaresoftware.. ThThee procesprocesss ooff depositdeposit imageimage conversionconversion toto blacblackk anandd whitwhitee isis illustrateillustratedd iinn FigurFiguree 2.4.2.4. 2.2.55 DetaileDetailedd leachinleachingg kinetickineticss evaluationevaluation LeachinLeachingg experimentexperimentss werweree carriedcarried ououtt foforr variouvariouss ororee particlparticlee sizessizes ttoo evaluateevaluate detaileddetailed leachingleaching kinetickineticss andand sizesize dependencedependence behaviorbehavior.. ThesThesee experimentsexperiments werweree carriecarriedd outout forfor 144144 hourshours.. LeachanLeachantt foforr thesthesee experimentexperimentss wawass selecteselectedd fromfrom experimentsexperiments thathatt showcdshowed thethe higheshighestt recoverrecoveryy ooff coppercopper afterafter twtwoo daydayss ooff leachingleaching.. AlAlll ooff thesthesee experimentexperimentss werewere conducteconductedd atat rooroomm temperaturetemperature.. SolutioSolutionn mixinmixingg / stirringstirring wawass provideprovidedd bbyy meansmeans ooff a TeflonTeflon rotatorrotator.. A smallsmall amounamountt ooff oreore aass welwelll asas solutionsolution wawass taketakenn fromfrom thethe batbathh foforr chemicalchemical analysis.analysis. ThesThesee experimentsexperiments werweree performeperformedd usinusingg ththee followingfollowing parameterparameterss accordinaccordingg ttoo thethe sesett uupp shownshown iinn FigurFiguree 2.5.2.5. ParametersParameters:: 1.1. TemperatureTemperature:: RoomRoom temperaturetemperature 22.. RPM:RPM:20 2000 33.. MassMass ofof ore:ore: 2255 gramgram 44.. VolumVolumee ofof solution:solution: 500500 mlml 2525 D '- Threshold GJ IQl~ ~ l ~ l 255 _~ ______1lJ 255 D FigurFiguree 2.42.4:: StepsSteps toto obtainobtain a blacblackk andand whitwhitee imagimagee bbyy usinusingg imagimagee J software.software. TheThe imageimage iiss capturedcaptured,, thresholdedthresholded,, thethenn convertedconverted ttoo a blacblackk andand whitwhitee image.image. 2266 Rotator Temperature Controlled Speed Control bath FigurFiguree 2.52.5:: SchematiSchematicc diagradiagramm representinrepresentingg a stirredstirred,, batcbatchh leachinleachingg testestt setusetupp usinusingg a constanconstantt temperaturtemperaturee bath.bath. CHAPTERCHAPTER 3 RESULTRESULTSS ANANDD DISCUSSIONDISCUSSION 3.13.1 EvaluationEvaluation ooff primarprimaryy combinecombinedd leachinleachingg andand electroelectrowinnin winningg experimentsexperiments TheThe goalgoal ofof thithiss investigatioinvestigationn wawass ttoo evaluatevaluatee ththee viabilitviabilityy ooff extractioextractionn andand recoverrecoveryy ofof coppecopperr bbyy combinedcombined leachinleachingg ofof chalcopyritchalcopyritee ororee andand electroplatinelectroplatingg ooff ththee coppercopper extracted.extracted. SeveralSeveral attemptsattempts havhavee alreadyalready beebeenn madmadee iinn ththee leachingleaching ofof chalcopyritechalcopyrite concentrateconcentrate.. MostMost ofof thethe associateassociatedd researcresearchh iiss donedone usinusingg sulfatesulfate medimediaa aass ththee leachinleachingg solution.solution. IInn ththee cascasee ofof sulfatesulfate medimediaa leachinleachingg ooff chalcopyritechalcopyrite,, iitt wawass commonlcommonlyy observeobservedd thathatt mineraminerall particlesparticles becambecamee progressivelprogressivelyy envelopedenveloped witwithh thickeninthickeningg layelayerr ofof elementaelementall sulfursulfur,, whicwhichh causescauses impedanceimpedance ttoo leachinleachingg [10].[10]. LeachinLeachingg ooff chalcopyritchalcopyritee oreore witwithh chloridechloride medimediaa hahass beenbeen showshownn ttoo bbee fasterfaster thathann sulfatesulfate medimediaa duduee ttoo a reductioreductionn ooff passivation.passivation. ChloridChloridee solutionsolution containingcontaining coppercopper ionionss formformss cuprouscuprous anandd cupricupricc ioIOnn complexes,complexes, + (CuCl(CuCI+,, CuCb-,CuCl2~, CuCh-CuCl3~ anandd CuCli-)CuCl/") [13].[13]. StabilityStability ofof coppecopperr ionionss duduee ttoo ththee formationformation ofof chloro-complexechloro-complexess enhancesenhances leachingleaching efficiencyefficiency [14-15].[14-15]. DissolutioDissolutionn ofof CuFeS2CuFeS2 cacann bebe expressedexpressed bbyy reactionreactionss [3.1][3.1] andand [3.2].[3.2]. 2+2+ 4 C + 2+2+ 2 0 CuFeSCuFeS2(s)2(S) + 33Cu C u = 4 Cuu + Fe + 2 S° [3.1[3.1 ] + 2 CuFeS2(s)CuFeS2(s) + 3 [CuClt[CuCl] + 1111C1 cr" = 4 [CuCl[Cucht3] ~ + FeClFeCb2 + 2 S [3.2][3.2] 2288 CommoCommonn sourcesourcess ooff free chloridchloridee ionionss araree NaClNaCI,, HCHCI1 anandd CaCl2CaCb.. AlthougAlthoughh combinedcombined leachinleachingg anandd electrowinninelectrowinningg iiss dondonee usinusingg CaClCaCb2 aass welwelll aass NaClN aCI,, CalciuCalciumm chloridchloridee iiss moremore usefuusefull iinn preventinpreventingg JarositJarositee formatioformationn bbyy removinremovingg SOSO/4 "-.. HydrometallurgicaHydrometallurgicall extractioextractionn ooff coppecopperr fromfrom chalcopyritchalcopyritee bbyy chloridchloridee medimediaa cacann bebe explaineexplainedd bbyy reactionreactionss discussediscussedd previouslpreviouslyy [15][15].. IInn thithiss typtypee ooff leachingleaching,, solutiosolutionn iiss continuouslcontinuouslyy circulatecirculatedd iinn aann electrowinninelectrowinningg chamber/reservoirchamber/reservoir.. ThThee maimainn reactioreactionn aatt thethe electrowinninelectrowinningg anodanodee iiss describedescribedd aass equatioequationn [3[3.3].3].. + H20 -> [O] + 2H + 2e" E° = 1.23 V [3.3][3.3] ThiThiss operatiooperationn generategeneratess nascennascentt oxygeoxygenn whicwhichh cacann oxidizoxidizee ferrouferrouss iolOnn ttoo ferriferricc lOnion accordinaccordingg ttoo ththee reactionreaction:: 2+ + 3+ 2 Fe + 2H + [O] -> 2 Fe + H2Q [3.4][3.4] TheThe resultinresultingg ferricferric ioionn cancan assisassistt leachinleachingg accordinaccordingg ttoo ththee reaction:reaction: 3+ 2+ 2+ CuFeS2 + 4 Fe -> Cu + 5Fe + 2S [3[3.5.5]] 2 Generated Cu94+- can be plated at the cathode according to the reaction: Generated Cu can be plated at the cathode according to the reaction: Cu2+ + 2e"^Cu° EOE° = 0.340.34 V [3[3.6.6]] 2929 3.1.13.1.1 ConsumptionConsumption ofof acidacid AciAcidd consumptioconsumptionn isis highhigh initially,initially, andand thethenn itit becomesbecomes constantconstant afterafter a periodperiod ofof a fewfew daydayss inin mostmost ofof ththee teststests performedperformed inin thisthis study.study. InitialInitial highighh consumptioconsumptionn ofof acidacid isis thethe resulresultt ofof reactionreactionss nearnear ththee surfacesurface ofof oreore particles.particles. InitialInitial pHpH isis kepkeptt loloww asas leachinleachingg isis feasiblefeasible inin ththee lowlow pHpH regimeregime.. TheThe cumulativecumulative acidacid consumptionconsumption peperr unitunit massmass ofof oreore approachesapproaches a constanconstantt valuevalue.. OneOne possiblepossible explanationexplanation forfor thithiss isis ththee formationformation ofof a reactionreaction producproductt layerlayer atat ththee surfacesurface ofof thethe mineraminerall particleparticle.. AnotherAnother possiblepossible reasonreason isis thathatt a highhigh amountamount ooff acidacid isis neededneeded initiallyinitially toto dissolvedissolve acidacid solublesoluble components.components. OnceOnce thesethese componentscomponents dissolvedissolve fromfrom ththee ore, veryvery littlelittle acidacid isis consumed.consumed. ThusThus thethe acidacid consumptionconsumption ratratee declinesdeclines significantlysignificantly afterafter a fewfew days.days. OneOne setset ofof resultresultss forfor acidacid consumptionconsumption isis shownshown iinn FigureFigure 3.13.1.. g 0.6 ..a. E 0.5 111- ::l ~ g ~ 0.4 o 0 ~ E 0.3 o ra ra ~ ~ ~0.2 ..ra- E 0.1 o o0 2 4 6 8 1010 1212 1414 Time(DaysTime(Days)) FigureFigure 3.13.1:: CumulativeCumulative acidacid consumption/gramconsumption/gram ofof oreore iiss shownshown forfor combinedcombined columncolumn leachingleaching andand EEWW testestt asas discussediscussedd inin sectionsection 2.5.1.2.5.1. TheThe compositioncomposition ooff solutionsolution isis alsoalso mentionedmentioned inin TableTable 2.12.1.. 3030 3.1.23.1.2 ConcentratioConcentrationn ofof coppercopper andand ironiron (lCPMS(ICPMS analysis)analysis) ThThee resultresultss ofof ICPMICPMSS analysisanalysis ooff leachingleaching solutionssolutions areare shownshown inin FigureFigure 3.23.2 andand FigureFigure 3.33.3 TheThe sequencesequence ofof coppercopper extractionextraction isis assumedassumed asas follows:follows: 3 1.1. CopperCopper isis liberatedliberated fromfrom CuFeS2CuFeS2 bbyy Fe3+-'-,, itit causingcausing increasedincreased dissolveddissolved coppercopper concentrationconcentration iinn ththee columncolumn 94- 2. Movement of dissolved copper (Cu2+) from the column to the electrowinning 2. Movement of dissolved copper (Cu ) from the column to the electrowinning 2 chamber which increases Cu + concentration in electrowinning chamber chamber which increases Cu concentration in electrowinning chamber 3. Increased mass of the working electrode due to electroplating of copper 3. Increased mass of the working electrode due to electroplating of copper 4. Reduced copper concentration in the solution returning to the leaching column 4. Reduced copper concentration in the solution returning to the leaching column A slow rate of increment of dissolved copper increase indicates copper electroplating is A slow rate of incremen2 t of dissolved copper increase indicates copper electroplating is faster than the rate of Cu + transfer from the column to the electrowinning chamber. It can faster than the rate of Cu transfer from the column to the electrowinning chamber. It can 3 2 also be assumed that the total iron is the sum ofFe + and Fe + ions. There is likely a lowering also be assumed that the total iron is the sum of Fe and Fe ions. There is likely a lowering in concentration of ferrous ion and increase of concentration of ferric ions. Concentration in concentration of ferrous ion and increase of concentration of ferric ions. Concentration increase of iron in electrowinning chamber might be due to increase in concentration of increase of iron in electrowinning chamber might be due to increase in concentration of ferrous ion (ferric ion assisted leaching). ferrous ion (ferric ion assisted leaching). 3.1.3.1.33 RecoveryRecovery o0 f CopperCopper bbyy EIElectrowinnin ectrowinningg CumulativeCumulative recoverrecoveryy ofof electrowonelectrowon coppercopper isis representerepresentedd inin FigureFigure 3.4.3.4. AAss 6.36.3 gramsgrams ofof coppecopperr waswas addedadded initiallyinitially inin ththee formform ofof chloridechloride salt,salt, itit cancan bebe observedobserved thathatt mostmost ofof thethe initiallinitiallyy dissolveddissolved coppercopper wawass recoveredrecovered withinwithin 6 days.days. ItIt cancan bbee observedobserved thathatt thethe ratratee ofof coppercopper recoverrecoveryy isis fasterfaster initially,initially, andand thenthen itit achievesachieves a constantconstant slowerslower rate.rate. ThisThis behaviorbehavior cancan bebe understoounderstoodd bbyy ththee factfact thatthat raterate ofof recoveryrecovery dependsdepends onon coppercopper dissolveddissolved inin solution.solution. InitiallyInitially ththee amountamount ofof coppercopper isis highighh andand subsequentlysubsequently itit decreasesdecreases asas coppercopper isis beingbeing extractedextracted frofromm solutionsolution byby electrowinning.electrowinning. AnalysisAnalysis ofof FigureFigure 3.43.4 impliesimplies thatthat combinedcombined 3131 00.007.00788 -0 E • ...IVR5 O01) 00.007.00766 -E ...IVTO ~—Os '0 ]Q)g ~2 0.00740.0074 > 0o • 0 I/) I/) '0... 00.007.00722 Q) a.Q- a.Q- 0O Uo 00.00.0077 • 0 2 3 4 5 6 7 TimeTime ofof leachingleaching (days)(days) FigureFigure 3.2:3.2: ConcentrationConcentration ofof coppercopper (gram/gram(gram/gram ofof ore)ore) forfor combinedcombined leachinleachingg andand electrowinningelectrowinning testtest.. TheThe compositioncomposition ofof solutionsolution isis mentionementionedd inin TableTable 2.1.2.1. TheThe experimentexperiment wawass carriedcarried outout atat rooroomm temperaturtemperaturee andand averageaverage raterate ofof electrowinningelectrowinning ofof 22 1010 mA/cmmA/cm •. 3232 -o0 0.016 E 0.014 • ~ '-(0 01 i_ 0.012 • -E ~Ui E'- 0.01 re01- - Q) 3-5"0 '-- 0.008 Q) 0 ~> 0.006 0 IIIo .~w 0.004 • "0T3 r:::: 0.002 C0 '-o 0 0 2 4 66 8 TimTimee ofof leaching(days)leaching(days) FigurFiguree 3.3:3.3: ConcentrationConcentration ofof dissolveddissolved ironiron (gram/gram(gram/gram ofof ore).ore). TheThe compositioncomposition ofof solutionsolution iiss mentionementionedd inin TableTable 2.12.1.. 3333 1.4 • 1.2 • • • 1 • •• • 0.8 0.6 • 0.4 • 0.2 o o0 5 1010 1515 2200 Time(daysTime(days)) FigurFiguree 3.43.4:: CumulativeCumulative recoverrecoveryy ooff coppercopper foforr testestt asas discussediscussedd iinn sectiosectionn 2.4.12.4.1.. TheThe compositioncomposition ooff solutiosolutionn iiss alsoalso mentionementionedd iinn TablTablee 2.12.1.. leachinleachingg andand electrowinningelectrowinning cacann bbee potentiallpotentiallyy feasible.feasible. ItIt iiss obviouobviouss fromfrom ththee grapgraphh thatthat initiainitiall dissolvedissolvedd coppecopperr iiss recovererecoveredd withiwithinn 6 days.days. ThThee sourcesource ofof remaininremainingg coppercopper iiss thethe oreore.. 3.23.2 AnalysiAnalysiss ofof factorialfactorial designdesign columncolumn leachingleaching experimentsexperiments ThThee ppHH ofof leachinleachingg solutionsolution beforbeforee anandd afteafterr leachinleachingg presentepresentedd inin FigureFigure 3.3.55 showsshows a trend.. A larglargee changchangee inin ppHH isis observeobservedd forfor ththee solutionsolution havinhavingg a loloww concentrationconcentration ooff acid.acid. ThiThiss trentrendd iiss justifiejustifiedd becausbecausee consumptioconsumptionn ofof aciacidd causecausess larglargee changeschanges inin ppHH inin ththee highighh pHpH regimeregime.. PotentiostatiPotentiostaticc measurementmeasurementss carriedcarried outout bbyy LundstromLundstrom eett al.al. suggessuggestt thathatt thethe reactionreaction mechanismechanismm (leaching(leaching ofof chalcopyritechalcopyrite witwithh chloridechloride media)media) changeschanges betweebetweenn ppHH 2 andand 22.2.255 3344 44 3.5 o pH (before) 3 • pH(after) 2.5 J: Q. 2 1.5 1 TesTestt I10D FigurFiguree 3.53.5:: ComparisoComparisonn ooff ppHH ooff leachinleachingg solutiosolutionn beforbeforee anandd afteafterr leaching,leaching, compositiocompositionn ooff solutiosolutionn iiss presentepresentedd iinn TablTablee 2.2.22 foforr eaceachh testestt ID.ID. 3355 [15].[15]. ItIt causecausess ththee fonnationformation ofof passivpassivee layelayerr onon ththee surfacsurfacee ooff mineral/ormineral/oree whicwhichh impedesimpedes dissolution,dissolution, whichwhich isis normallnonnallyy highehigherr atat loloww pHpH.. ThThee objectivobjectivee ofof ththee factoriafactoriall designdesign experimentexperiment iiss ttoo evaluateevaluate combinationcombinationss ofof allall indicateindicatedd ioniionicc species,species, mentionementionedd inin TablTablee 2.12.1,, whicwhichh causecause maximumaximumm recoverrecoveryy ooff coppercopper.. AnotheAnotherr purpospurposee ooff ththee factorialfactorial designdesign experimenexperimentt isis ttoo studstudyy thethe effecteffect ooff individuaindividuall factorsfactors onon ththee responsresponsee variablevariable.. TheThe combinatiocombinationn ofof parameteparameterr showingshowing minimumImmumm coppercopper anandd iroironn concentratioconcentrationn Inin ththee oreore residueresidue,, whicwhichh correspondscorresponds ttoo ththee maximumaximumm leachingleaching,, wawass selecteselectedd foforr a mormoree detaileddetailed leachinleachingg kinetickineticss study.study. DreisingeDreisingerr etet al.al. [16][16] havhavee alreadalreadyy reportereportedd enhanceenhancedd leachinleachingg iinn thethe presencpresencee ooff chloridechloride mediamedia.. OneOne ooff ththee advantageadvantagess ooff chloridchloridee medimediaa leachinleachingg iiss thathatt thertheree isis a lowlow overpotentialoverpotential toto oxidationoxidation ofof sulfides.sulfides. ThisThis lowlow overpotentialoverpotential toto oxidationoxidation isis notnot observedobserved inin sulfatesulfate basebasedd leachingleaching.. AlthoughAlthough iitt iiss harhardd ttoo makmakee conclusionsconclusions frofromm variousvarious studiestudiess becausbecausee ofof differentdifferent experimentalexperimental conditions,conditions, somesome ooff whicwhichh araree controversial,controversial, iitt isis likellikelyy thathatt mormoree thathann oneone phenomenophenomenonn iiss involveinvolvedd iinn ththee inhibitioinhibitionn ofof chalcopyritechalcopyrite leaching.leaching. A combinationcombination ofof ferric/ferrousferric/ferrous ioionn andand cupric/cuprouscupric/cuprous ionsions mighmightt havehave a synergisticsynergistic effecteffect [17].[17]. ThiThiss studystudy wawass undertakeundertakenn ttoo investigateinvestigate thesthesee effectseffects mormoree thoroughlythoroughly.. AlthoughAlthough fluctuatiofluctuationn iiss observeobservedd forfor IepICP datadata foforr differendifferentt setsetss ofof experimentsexperiments,, ththee datdataa follofolloww a similarsimilar trendtrend.. TheThe leachinleachingg solutionsolution witwithh loloww ferriferricc ionion,, highighh ferrouferrouss ionion,, highighh cupriccupric ionion,, lowlow cuproucuprouss ionion andand highighh acidacid quantitquantityy causescauses maximumaximumm leaching,leaching, thithiss combinationcombination showsshows consistencyconsistency forfor threthreee similarsimilar teststests,, andand henchencee thithiss combinationcombination wawass chosenchosen forfor a morcmore detailedetailedd analysisanalysis.. SeSett "0""0" representrepresentss ororee samplesample withouwithoutt leachinleachingg (tota(totall coppecopperr contentcontent inin oreore iiss 0.58%,0.58%, whicwhichh iiss iinn closeclose proximitproximityy ttoo typicatypicall loloww gradgradee oreore coppecopperr contentcontent)) [18].[18]. AccordingAccording ttoo WilsoWilsonn eett al.[6]al.[6] thethe ratiratioo ofof cuproucuprouss ttoo cupriccupric ionionss mustmust bbee leslesss thathann 1.91.9 iinn orderorder 3636 toto makmakee thethe followingfollowing reactioreactionn thermodynamicallythermodynamically mormoree feasiblfeasiblee duedue ttoo stabilitystability ooff cuprouscuprous ionsions inin complexes.complexes. + 2 CuFeS2(s)CuFeS2{s) + 3 [CuClt[CuCl] + 11cr11C1" == 44 [CuChf[CuCl3] ~ ++ FeChFeCl2 ++ 2S2S (~G0298(AG°298 == lOA10.4 Kcal/mol)Kcal/mol) [3.8][3.8] MauricMauricee eett al.[14a1.[14]] proposeproposedd reactioreactionn (equation(equation [3.9])[3.9]) whenwhen leachingleaching iiss carriecarriedd ououtt bbyy usingusing ferricferric chloride.chloride. + + CuFeS2(s)CuFeS2(s) + 4 FeCI/FeCl2 +3Cr=+3C1 = CuCCuCIl + ++ 55 FeClFeCh2 ++ 22SS (AG°(~G0298298 == -16.-16.77 Kcal/molKcal/mol)) [3.9[3.9]] whenwhen excesexcesss chloridchloridee ionion iiss presentpresent,, a possiblpossiblee reactionreaction iiss expressedexpressed aass equation:equation: CuFeS2(s)CuFeS2(s) + 3 FeClFeCh3 = CuCICuCl + 4 FeClFeCh2 + 2 SSO° [3.10][3.10] TheThe standardstandard freefree energyenergy changchangee ooff a leachinleachingg reactioreactionn witwithh ferriferricc chloridchloridee iiss negative,negative, whereawhereass thathatt witwithh cupricupricc chloridchloridee iiss positivepositive.. ThuThuss undeunderr standarstandardd conditionconditionss ferricferric chloridechloride leachingleaching iiss mormoree feasiblfeasiblee thathann cupricupricc chloridechloride leachingleaching.. CupriCupricc chloridchloridee leachingleaching isis thermodynamicthermodynamic feasiblefeasible inin highighh CuCI+CuCl+ andand crCI" concentrationsconcentrations.. WheWhenn ththee concentrationconcentration ofof + 2+ Cu+ aatt somesome stagestage reachereachess 1.91.9 timestimes ththee Cu + concentrationconcentration,, ththee freefree energyenergy changchangee ofof reactionreaction willwill nnoo longelongerr bbee negativnegativee anandd reactioreactionn wilwilll nnoo longerlonger spontaneous.spontaneous. AlthougAlthoughh ththee previoupreviouss reactionsreactions areare proposedproposed forfor ororee concentrateconcentrate,, reactionreactionss areare alsalsoo likelylikely ttoo occuroccur forfor leachingleaching ooff loloww gradegrade oreore inin testtestss wherewhere ththee ratiratioo ofof cuprouscuprous ttoo cupriccupric ioionn iiss 0.110.11 whicwhichh iiss leslesss thathann 1.91.9 forfor TesTestt IIDD Cu0901Fe0109H15Cu0901Fe0109H15.. ThiThiss combinationcombination resultresultss iinn maximummaximum 2 leachinleachingg ofof ore.ore. HencHencee ththee CuCu +I/ CCuu -'- ratiratioo factorfactor shoulshouldd havhavee a positivpositivee effeceffectt overover thethe responseresponse variablvariablee (recovery)(recovery) inin a statisticalstatistical analysis.analysis. ThiThiss observatioobservationn iiss evidentevident frofromm thethe 3737 resultsresults ofof ththee factorialfactorial designdesign analysisanalysis shownshown inin TableTable 3.1.3.1. TheThe dissolveddissolved coppercopper atat thethe endend ofof eacheach testestt isis representedrepresented inin FigurFiguree 3.6.3.6. HydrochloriHydrochloricc acidacid isis a sourcesource ofof chloridechloride ions.ions. Thus,Thus, thethe reactioreactionn iiss mormoree feasiblefeasible atat lowlow ppHH whenwhen thethe crCI" concentrationconcentration isis highhigh duedue ttoo thethe formatioformationn ofof chlorocomplexeschlorocomplexes [15].[15]. AAss expectedexpected ththee factorialfactorial designdesign analysisanalysis representedrepresented inin TableTable 3.1,3.1, showsshows thatthat highhigh HCIHC1 concentrationconcentration hahass a positivpositivee effecteffect overover ththee responseresponse variable.variable. TheThe factorialfactorial designdesign analysisanalysis utilizeutilizess coppercopper recovererecoveredd (gram/gram(gram/gram ofof ore)ore) asas thethe responseresponse variablevariable.. ThisThis valuvaluee cancan bbee calculatedcalculated bbyy deductingdeducting ththee amountamount ofof coppercopper inin ththee residueresidue fromfrom ththee totaltotal coppercopper presentpresent inin ththee baselinebaseline sample.sample. CopperCopper recoveryrecovery isis shownshown inin FigureFigure 3.7.3.7. ThThee factorsfactors useusedd iinn ththee factorialfactorial designdesign analysisanalysis are:are: 2 • VariableVariable 1 = Cu2+ / Cu+Cu+ = factorfactor 1 3 2 • VariableVariable 2 = FeFe ++// FeFe 2+ = factofactorr 2 • VariableVariable 3 = HCIHC1 concentrationconcentration = factorfactor 33 TheThe factoriafactoriall designdesign analysisanalysis resultresultss (as(as discusseddiscussed inin sectionsection 2.5.2)2.5.2) areare shownshown inin TableTable 3.13.1 wherewhere thethe effectseffects andand interactioninteraction parametersparameters areare presentedpresented.. AlAlll factorsfactors werewere determineddetermined toto bebe independentlindependentlyy statisticallystatistically significantsignificant basedbased onon theirtheir effecteffect onon ththee response.response. TheThe estimatesestimates ofof factorfactorss areare thethe deviationsdeviations ofof ththee meanmean ofof negativenegative settingssettings fromfrom thethe meanmean ofof positivepositive settingssettings foforr ththee respectiverespective factorsfactors basedbased onon testestt parameterparameterss inin TableTable 2.1.2.1. IfIf ththee valuevalue ofof variablevariable 1 (Cu(Cu 2+/Cu+)/Cu ) (ratio(ratio ofof concentration)concentration) isis changedchanged fromfrom lowlow toto highhigh,, thethe expectedexpected improvementimprovement ooff responsresponsee variablevariable (recovery)(recovery) isis 0.001026.0.001026. SimilarlySimilarly forfor variablvariablee (3),(3), ifif hydrochlorichydrochloric acidacid concentrationconcentration iiss changedchanged fromfrom lowlow ttoo highhigh,, wwee cancan expectexpect improvemenimprovementt bbyy 0.0017760.001776 withwith 3 0 respecrespectt toto initialinitial valuevalue.. BasedBased oonn 2 -" designdesign ofof experimentsexperiments modelmodel,, distributiondistribution ofof residualresidual valuevaluess werweree examined.examined. ThesThesee valuevaluess areare comparedcompared usingusing differencedifference betweenbetween predictepredictedd andand 3388 TablTablee 3.13.1:: FactorialFactorial desigdesignn analysisanalysis matrimatrixx forfor testtestss aass summarizesummarizedd iinn TablTablee 2.22.2,, coppercopper recoverrecoveryy isis chosenchosen aass ththee responsresponsee variablevariable FactoFactorr EffecEffectt StandardStandard ErrorError F P Mean/IntercMeanllnterc.. 0.0026880.002688 0.0001370.000137 - - (l)Varl(l)Varl 0.001020.0010266 00.00027.0002744 29.6419829.64198 0.1156410.115641 (2)Var2(2)Var2 -0.000924-0.000924 0.0002740.000274 1313.4444.444444 0.1695010.169501 (3)Var(3)Var33 0.001770.0017766 00.00027.0002744 65.7901265.79012 0.078090.0780933 1 byby 22 -0.000707-0.000707 0.000270.0002744 6.530866.53086 0.237450.2374511 1 byby 33 -0-0.00037.0003744 0.000270.0002744 3.56793.567900 0.309970.3099700 2 bbyy 3 -0.000557-0.000557 0.000270.0002744 4.456794.45679 0.281620.2816244 -eo 0.007 r- -o 0.006 E ...III 0.005 r-- - tn E 0.004 - ...III - ~ 0.003 r-- - ., r-- Q) > 0.002 "0 I/) 0.001 .,I/) ... o n Q) Q. Q. o U TestlDTest ID FigurFiguree 3.6:3.6: CoppeCopperr (gram/gra(gram/gramm ooff ore)ore) forfor digesteddigested ororee aass basebasedd onon ICICPP analysis.analysis. CompositionComposition ofof solutionsolution iiss presentepresentedd iinn TableTable 2.2.22 foforr eacheach test.test. 39 ~£ 0.0060.006 -r------'0o |E 0.0050.005 III ~J? 0.0040.004 E S~ 0.003 J> 0.003 1j 1~ 0.0020.002 > o> ~ 0.001 ...| 0.001 S~. 0 4-~~~~~~~--~~--~~--~~--~~--~~--~-----~ ac.. o Cu01·Cu01- Cu09 Cu09·- Cu01Cu01·- Cu09·Cu09- Cu01 Cu01·- Cu09·Cu09- Cu01·Cu01- Cu09Cu09·- uO 09Fe0109Fe01·- 0101Fe01 Fe01-· 09Fe09·09Fe09- 01Fe0901 Fe09·- 09Fe01·09Fe01- 01Fe0101 Fe01·- 09Fe0909Fe09·- 01Fe0901 Fe09·- 09H009H055 09H0509H05 01H001H055 01H0501H05 09H1 09H155 09H1 09H155 01H1501H15 01H1 01H155 TesTestt I10D FigurFiguree 3.7:3.7: CopperCopper recoveredrecovered forfor digesteddigested oreore determineddetermined bbyy ICPICP analysis.analysis. CompositioCompositionn ofof solutionsolution iiss presentedpresented iinn TableTable 2.2.22 foforr eacheach testestt ID.ID. 4400 observeobservedd valuevalue.. StatisticalStatistical significancsignificancee "p""p" levellevel iiss alsalsoo calculatecalculatedd bbyy STSTATISTIC A TISTICAA tool,tool, whicwhichh iiss measurmeasuree ooff ththee validitvalidityy ofof ththee resultresult.. ThThee valuvaluee ofpof p representrepresentss thethe decreasingdecreasing indexindex ofof reliabilitreliabilityy ooff ththee resultsresults.. OnlyOnly variablvariablee 3 showshowss a valuvaluee 0.078,0.078, whichwhich iiss iinn closeclose proximityproximity ttoo 0.050.05,, whicwhichh iiss ththee boundarboundaryy levellevel forfor validityvalidity.. ThusThus,, thethe effecteffect ooff variablvariablee 3 onon responsresponsee variablvariablee cancan bbee assumedassumed ttoo bbee statisticallstatisticallyy significantsignificant.. OtheOtherr valuevaluess ofof p araree lessless significant.significant. F statisticsstatistics werweree alsoalso evaluatedevaluated toto findfind thethe extentextent toto whicwhichh thethe meanmeanss ofof experimentalexperimental conditionsconditions differdiffer moremore thathann woulwouldd bbee expectedexpected.. F statisticstatisticss valuevaluess werweree calculatecalculatedd ttoo testestt thethe nulnulll hypothesishypothesis.. ItIt cancan bbee observedobserved thathatt a highighh cupriccupric ionion// cuproucuprouss ioionn ratiratioo hahass a positivepositive effeceffectt onon leachingleaching,, anandd highighh aciacidd concentrationconcentration alsalsoo hahass a positivpositivee effeceffectt oonn leaching.leaching. ThThee 3 DD ploplott (Figure(Figure 3.8)3.8) ooff coppercopper recoverrecoveryy versuversuss ratiratioo ooff cupriccupric ionion ttoo cuproucuprouss ioionn anandd ratiratioo ofof ferriferricc ionion ttoo ferrousferrous ioionn iiss drawndrawn usinusingg STSTATISTIC A TISTICAA 9 tooltool,, wherwheree thethe maximummaximum differencedifference regimregimee isis shownshown iinn ththee forfonnm ofof contours.contours. 3.3.33 AnalysiAnalysiss ofleachingof leaching experimentsexperiments AnalysisAnalysis ooff leachingleaching experimentsexperiments,, discussediscussedd iinn sectionsection 2.62.6,, ISis donedone foforr vanousvarious chalcopyritechalcopyrite ororee particlparticlee sizes.sizes. TheThe concentratioconcentrationn ooff coppercopper andand ironiron iinn leachinleachingg solutionsolution waswas detennineddetermined aatt differentdifferent timtimee intervalintervalss bbyy ICPMICPMSS analysisanalysis.. ChemicalChemical analysisanalysis ofof residuaresiduall oreore wawass alsoalso dondonee iinn regularegularr intervalsintervals.. ConcentratioConcentrationn ooff coppercopper iinn solutionsolution cancan bbee comparedcompared withwith ththee totatotall amountamount ooff coppercopper presenpresentt iinn ththee oreore.. TotaTotall recoverrecoveryy ofof chemicalchemical speciesspecies mustmust bebe equalequal ttoo totatotall depletiodepletionn ofof chemicachemicall speciespeciess iinn oreore.. ICICPP resultresultss ooff leachingleaching solutiosolutionn andand residuaresiduall oreore chemicalchemical analysianalysiss werewere comparecomparedd anandd foundfound ttoo bbee consistenconsistentt witwithh a masmasss balancebalance (standard(standard erroerrorr =5%)=5%).. FigurFiguree 3.93.9 presentpresentss ththee concentrationconcentration ofof coppecopperr atat differendifferentt timetime 4411 0.001 0.006 005 • > 0.005 0. _ < 0.0047 04 o·0 D < 0.0040 ~ • < 0.0037 03 <> S 0 _ < 0. 00 27 ~ o· ~ O.OOZ 01 O· 0 FigurFiguree 3.83.8:: 33DD contoucontourr ploplott foforr recovererecoveredd coppecopperr vs.. differendifferentt factorsfactors,, basebasedd oonn outputoutput ooff factoriafactoriall desigdesignn experimentsexperiments.. DetailDetailss ooff experimentexperimentss araree presentepresentedd iinn TablTablee 2.2.2.2. 4242 4 3.5 ::::::: -E Cl... -G) 3 c. c. -+- (-14+35) mesh 0 U ___ (-4+14) mesh 2.5 -6- (-270) mesh 2 o 1 2 3 4 5 6 7 Time (day) FigureFigure 3.93.9:: ConcentrationConcentration ofof CuCu (gmlliter)(gm/liter) vs.vs. timtimee forfor 2525 gramsgrams ofof chalcopyritechalcopyrite oreore waswas usedused iinn 505000 mlml ofof solutionsolution (Test(Test IDID Cu0901Fe0109H15).Cu0901Fe0109H15). AllAll experimentsexperiments werewere carriedcarried outout forfor 144144 hourshours atat roomroom temperature.temperature. intervals.. TheThe goalgoal ofof thesthesee leachingleaching experimentsexperiments waswas ttoo determinedetermine thethe timetime dependentdependent conversionconversion oorr disdissolutiosolutionn ofof chalcopyritechalcopyrite oreore particlesparticles.. TheThe resultinresultingg leachingleaching datadata cancan bebe usedused toto predicpredictt ththee recoverrecoveryy forfor differentdifferent oreore particleparticle sizessizes asas welwelll asas toto predictpredict economiceconomic viabilitviabilityy ofof ththee operation.operation. DataData obtainedobtained frofromm ICPICP analysesanalyses ofof solutionssolutions ccaan bbee usedused toto determinedetermine whichwhich modelmodel besbestt describesdescribes reactionreaction kineticskinetics ofof solidsolid ororee particleparticle leaching.leaching. TwoTwo leachingleaching modelsmodels werweree evaluatedevaluated usinusingg thethe setset ofof datadata. 3.3.3.3.11 Modell:Model 1: sphericalspherical particlparticlee undeunderr reactioreactionn controlcontrol WhenWhen reactioreactionn controlledcontrolled leachingleaching involvesinvolves purepure particleparticless witwithh oror withouwithoutt producproductt layerslayers asas welwelll asas particlesparticles witwithh piecepiecess interlockeinterlockedd iinn a nonreactivenonreactive matrix,, thisthis modemodell cancan bbee used.used. 4433 ThiThiss assumptioassumptionn cacann bbee expresseexpressedd aass equatioequationn [3.11].[3.11]. tt a 1-(1-a)l-(l-a) 1/1I33 [3.11[3.11]] wherwheree tt = timtimee ooff leachingleaching a = fractiofractionn reactedreacted 3.3.3.3.22 ModeModell 22:: sphericasphericall particlparticlee undeunderr producproductt layelayerr controlcontrol IInn ModeModell 2 aann entitentityy iiss disseminatedisseminatedd withiwithinn a nonreactivnonreactivee matrixmatrix.. ModeModell 2 alsalsoo applieappliess ttoo casecasess iinn whicwhichh producproductt layelayerr iiss formeformedd oonn purpuree particles.particles. ModeModell 2 kinetickineticss leadleadss toto:: t a l-3(l-arI-3(1-a)2/J 3 + 2(I-a)2(l-a) [3.12[3.12]] wherwheree t iiss timtime;e ; a = fractionfraction reactedreacted ItIt iiss assumeassumedd thathatt alalll ororee particleparticless foforr analysisanalysis areare spherical.spherical. ThThee fitfit ooff datdataa ttoo ModeModell 2 iiss presentepresentedd iinn FigurFiguree 3.1 0 whereawhereass thatthat forfor ModeModell 1 iiss shownshown inin FigurFiguree 3.113.11.. DatDataa inin FigureFigure 3.103.10 andand 3.113.11 indicateindicate ththee loweslowestt correlationcorrelation coefficientcoefficient valuevalue isis forfor ththee smallestsmallest sizesize particle.particle. OneOne reasonreason forfor thisthis deviationdeviation isis thatthat -270-270 meshmesh particlesparticles containcontain a rangrangee ofof differentdifferent particlparticlee sizes,sizes, whereaswhereas thethe leachingleaching modelmodelss assumeassume monosizemonosize particles.. TheThe -4-4+1 +144 sizesize particlesparticles provideprovide thethe bestbest modelmodel fitfit forfor leachingleaching byby thethe ModelModel 2 kinetics.kinetics. 4444 0.3 1.2 • -270 mesh 0.25 M • (-4+14) mesh Y = 0.0016x - 0.0347 • N R2 = 0.8078 -< 0.2 ~ (-14+35) mesh 0.8 n:s -I "("'" 0.15 0.6 n:s I -n:s M 0.1 y=O 0.4 N -I R2 = 0.9539 "("'" 0.05 y = 5E-05x - 0.0005 0.2 R2 = 0.9647 0 • 0 0 20 40 60 80 100 120 140 160 Time(hours)Time(hours) FigureFigure 3.10:3.10: LeachinLeachingg parameteparameterr 1_3(I_a)2l-3(l-a) /3 + 2(l-a2(I-a)) vsvs.. timtimee foforr 2255 gramgramss ofof chalcopyritechalcopyrite ororee wawass useusedd inin 505000 mmll ooff solutiosolutionn (Tes(Testt IDID Cu0901Fe0109H15)Cu0901FeOl09HI5).. AllAll experimentsexperiments werweree carriedcarried ououtt foforr 144144 hourshours atat rooroomm temperature.temperature. 4545 0.7 1.2 • -270 mesh • 0.6 • (-4+14) mesh y = 0.0042x - 0.0525 1 R2 = 0.9038 fl (-14+35) mesh 0.5 0.8 M oor- -< 0.4 -co y = 0.0031x + 0.0022 0.6 co oor-• R2 = 0.989 • 0.3 -oor- 0.4 0.2 y = 0.0006x + 0.0042 R2 = 0.9913 0.1 • 0.2 0 0 0 50 100 150 200 Time (hours) FigureFigure 3.11:3.11: LeachingLeaching parameteparameter"r " 1-(1-a)Il-(l-a) /3"" vs.vs. timtimee forfor 2255 gramgramss ooff chalcopyritechalcopyrite oreore waswas useusedd iinn 500500 mmll ooff solutionsolution (Tes(Testt IDID Cu0901Fe0109H15)Cu0901FeOl09HI5).. AlAlll experimentsexperiments werewere carriedcarried ououtt foforr 144144 hourhourss atat rooroomm temperature.temperature. 4466 3.3A4 AnalysiAnalysiss ooff factoriafactoriall desigdesignn electrowinningelectrowinning ExperimentsExperiments 3.4.3 A .1l ComparisoComparisonn ooff currencurrentt efficiencyefficiency (experimental(experimental andand simulated)simulated) ElectrowinninElectrowinningg iiss carriedcarried outout usinusingg electrolyteselectrolytes aass discusseddiscussed iinn sectionssections 2.2.22 andand 2.32.3.. EachEach electrolyteelectrolyte containscontains a varietvarietyy ooff ioniionicc species.species. TheThe concentrationsconcentrations ooff speciesspecies inin thisthis studystudy werweree calculatecalculatedd usinusingg VisuaVisuall MinteMinteqq softwaresoftware.. TheseThese valuevaluess araree shownshown iinn AppendiAppendixx A.A. 2 2 3 MajorMajor ioniionicc speciesspecies iinn ththee electrolyteelectrolyte araree CCuu +, CCuu +, CuClCuCb-2" ,Fe, Fe +, FeFe + , H + ,cr, CI" anandd OKOH" ionsions.. AlAlll otherother ioniionicc speciesspecies areare neglecteneglectedd asas theitheirr concentratioconcentrationn iiss ververyy lowlow.. RecoveryRecovery ofof coppecopperr aatt ththee workinworkingg electrodelectrodee occuroccurss duduee ttoo reductioreductionn ooff coppecopperr fromfrom cupriccupric andand cupriccupric ionionss asas welwelll aass fromfrom coppecopperr chloridechloride complexescomplexes.. TheThe followinfollowingg areare ththee reactionreactionss ooff greatestgreatest importanceimportance,, writtewrittenn as:as: Cuz+ +2e" Cu [3.13][3.13] Cu + e" Cu [3.14][3.14] CuCl2" + e"-»Cu + 2Cl [3.15][3.15] Fe 2+ [3.16][3.16] + 2H + e" -> H2 [3.17][3.17] + 2H20 4H + 02 + 4e" [3.18][3.18] [3.19][3.19] 4747 TheThe ratiratioo ooff weighweightt ofof coppercopper metametall depositedepositedd onon ththee cathodcathodee ttoo ththee theoreticatheoreticall weightweight obtainedobtained fromfrom Faraday'Faraday'ss LaLaww iiss usedused ttoo calculatcalculatee currencurrentt efficiency,efficiency, writtewrittenn asas equationequation [3.20-3.22][3.20-3.22] „ . . WeighWeightt ooff metametall deposidepositt _ Current efficiencyr£ = r[3.20] Current efficiency = Theoretical weight obtained from Faraday's Law [3.20] Theoretical weight obtained from Faraday's Law ! . , . , TotaTotall chargchargee flofloww _ _. _ where theoreticalt weight = r [3.21] where theoretical weight = charge require for one mole of deposit P-21J charge require for one mole of deposit TotaTotall chargecharge = CurrentCurrent densitdensityy * areareaa * timtimee durationduration ofof currencurrentt flowflow [3.22][3.22] InIn ththee casecase ooff ththee reductioreductionn reactionreactionss occurrinoccurringg aatt aann electrodeelectrode,, thethe theoreticatheoreticall masmasss cacann bebe calculatecalculatedd iinn ththee followingfollowing mannemannerr (base(basedd oonn discussiodiscussionn iinn sectiosectionn 1.2):1.2): TotalTotal coppecopperr iinn ththee solutiosolutionn cancan bbee representerepresentedd asas:: [Cu][Cu] CoppeCopperr complexecomplexess anandd ioniionicc formformss iinn thithiss studstudyy cacann bbee representerepresentedd primarilprimarilyy asas:: [Cu+],[Cu+], 2+ [Cu ], and [CuCl2"] TheThe totatotall concentratioconcentrationn ooff coppercopper iiss ththee susumm ooff individuaindividuall ioniionicc speciesspecies concentrationconcentrationss andand showshownn inin equatioequationn [3.23].[3.23]. + 2+ [Cu] = [Cu ] + [Cu ] + [CuCl2~] [3.23][3.23] ThThee totatotall masmasss anandd theoreticatheoreticall weighweightt cacann bbee expresseexpressedd asas shownshown bbyy equatioequationn [3.24].[3.24]. TheoreticaTheoreticall weighweightt anandd totatotall chargchargee flowflow araree expresseexpressedd aass equationequationss [3.25][3.25] anandd [3.26],[3.26], respectivelyrespectively.. 4488 Total charge flow r .„ 2+2 _._ r^ ,.,1 _ Mass = Total charge flow x[Cu ++] / 1 + [Cu2+ +] / 2 + [CuCl; ] Mass= - xlCu ]/\ + [Cu ]/2 + [CuCl ]/l11]| [3.24[3 .24]] [Cu] x 2 [Cu] x 9648596485 Q wherwheree theoreticatheoreticall weighweightt = ——— [3.25][3.25] 96485.96485.33 0Q = CurrenCurrentt densitdensityy x area x timtimee ooff currencurrentt flofloww [3.26][3.26] FoForr electrodepositioelectrodepositionn ooff coppecopperr only,, reactioreactionn [3.13][3 .13],, [3.14],, anandd [3.15[3.15]] araree considereconsideredd asas 22+ + ththee reactionreactionss ooff importancimportancee anandd henchencee Cu +,, Cu+ anandd CuCkCuCh" - araree considereconsideredd foforr reduction.. 2 ThThee reactioreactionn involvininvolvingg ththee conversioconversionn ooff CuClCuCI3{" ttoo coppecopperr conversioconversionn iiss ignoreignoredd becausebecause 2 concentratioconcentrationn ooff C11CI3CuCb 2"- isis 100100 timestimes lowerlower thanthan thethe CuChCuCl2"- concentration.concentration. OtherOther complexescomplexes araree ignoreignoredd becausbecausee ooff theitheirr loloww concentrations.concentrations. ExperimentaExperimentall currencurrentt efficiencefficiencyy cacann bbee determinedeterminedd iinn ththee followinfollowingg steps: A generagenerall electrochemicaelectrochemicall reactioreactionn cacann bbee writtewrittenn aass equatioequationn [3.27].[3.27]. OOxx + ne"- -~> RedRed [3.27][3.27] "Ox" iiss ththee oxidizedoxidized formform ofof speciesspecies andand "Red" iiss ththee reducereducedd formform ofof speciesspecies.. ThThee ratratee ofof electrochemicalelectrochemical reactioreactionn cancan bbee writtewrittenn asas equationequation [3.28].[3.28]. RateRate (forward(forward reaction)reaction) = krkfoorwarrwadrd [Ox][Ox] [3.28][3.28] SimilarlySimilarly backwardbackward reactionreaction cancan bbee expressedexpressed asas equationequation [3.29][3.29]. 4499 RateRate (backwar(backwardd reactionreaction)) = kbacakwarckwardd [Red][Red] [3[3.29.29]] CurrentCurrent densitydensity cacann alsoalso bbee determineddetermined usinusingg ththee equatioequationn [3.30).[3.30]. I bbackwarac kwardd =- Z F kbkbackwarackwardd [Red][Red] [3[3.30.30]] wherwheree n iiss ioionn charge,, z isis electronselectrons involveinvolvedd iinn ratratee determiningdetermining step,, anandd F isis faradayfaraday constant.constant. AnodiAnodicc currentcurrent cacann bbee writtewrittenn asas equatioequationn [3.31).[3.31]. lia =- F KbackwarKbackwardd CrCreductioeductionn exexpp (aaFEicmFE hT ) [3.31[3.31]] Similarly,, cathodicathodicc currentcurrent cacann bbee writtewrittenn asas equatioequationn [3.32).[3.32]. i = F Kforward C ation exp f- OcFE/ J)J [3[3.32.32]] i c = F Kforward Coxidoxidation exp ( - acFER hr ) wherwheree Uaa andand aUc araree chargecharge transfetransferr coefficients.coefficients. ItIt iiss ofteoftenn assumedassumed that:that: aUa + Uacc = 1 BaseBasedd onon discussiodiscussionn iinn sectionsection l.21.2,, ButlerButler --VolmeVolmerr equatioequationn isis writtewrittenn aass equatioequationn [3.33).[3.33]. 5050 ._ .[ (aaFl]/) (-acFl]/)] [3.33][3.33] li -— -lo—i Q expexp IRT - exp IRT 11rj = EE-- EoE0 wherewhere EEoo iiss ththee NernsNemstt equilibriuequilibriumm potentiapotentiall atat zerozero currentcurrent density.density. UsUsee ofof ththee Butler-VolmerButler-Volmer equatioequationn iiss justifiejustifiedd whewhenn electricaelectricall currencurrentt aatt ththee electrodeelectrode dependsdepends oonn electrodeelectrode potentialpotential.. WheWhenn ththee electrodeelectrode reactionreactionss areare masmasss transfetransferr controlled,controlled, currencurrentt nnoo longerlonger dependdependss onon potentialpotential.. InsteadInstead,, undeunderr masmasss transportransportt controcontroll ratratee iiss limitedlimited bbyy diffusiodiffusionn aatt ththee limitinglimiting currencurrentt densitydensity,, iLiL-. ThisThis relationshirelationshipp isis expresseexpressedd aass equationequation [3.34].[3.34]. nFDC b [3.34][3.34] 8 wherwheree n iiss numbenumberr ooff electronselectrons involvedinvolved inin ththee electrodeelectrode reactionreaction F = FaradayFaraday constant,constant, D = DiffusionDiffusion constant,constant, 8 = DiffusionDiffusion layerlayer thickness,thickness, Cb = BulkBulk concentratioconcentrationn A modifiemodifiedd Butler-VolmeButler-Volmerr equationequation whicwhichh correctscorrects forfor masmasss transporttransport waswas useusedd iinn thisthis study.study. SolutioSolutionn resistancresistancee isis considereconsideredd anandd compensatedcompensated.. ThThee currencurrentt potentiapotentiall relationshiprelationship (plot(plot ooff E vsvs.. lologg Iii),|i|), givegivess informatioinformationn forfor singlesingle aass welwelll asas multiplmultiplee electrochemicalelectrochemical reactionreactionss occurrinoccurringg inin ththee system.system. ReactioReactionn potentiapotentiall cacann alsalsoo bbee determineddetermined fromfrom currentcurrent flowflow informationinformation.. IndividuaIndividuall currencurrentt cacann alsalsoo determineddetermined bbyy findingfinding ththee abscissabscissaa forfor eacheach reactionreaction asas shownshown inin FigurFiguree 3.123.12.. CurrentCurrent efficiencefficiencyy foforr multiplmultiplee reactioreactionn systemsystemss cancan bebe 5511 ReactionReaction 3 Reaction 2 E SumSum ooff reactionsreactions --- \ EEo0 \ ... loglog 11III1 logl111logliil log|l2| log|l3| LlogHog IIIIII FigureFigure 3.123.12:: LogLog (Current(Current)) vsvs.. PotentiaPotentiall grapgraphh forfor a multielectrochemicamultielectrochemicall reactionreaction system.system. ThreThreee differentdifferent reactionsreactions araree considereconsideredd ttoo demonstratedemonstrate ththee ratratee ofof reactionreaction calculationcalculation foforr individuaindividuall asas welwelll aass overalloverall currencurrentt efficiency.efficiency. calculatedcalculated byby addingadding ththee currentcurrent densitdensityy forfor ththee sumsum ofof coppecopperr reductioreductionn reactionreactionss dividedividedd byby ththee totatotall cathodiccathodic currencurrentt densitydensity.. ItIt cacann bbee expresseexpressedd asas equationequation [3.35].[3.35]. I current( Copper) Current efficiency = " [3[3.35.35]] L. current( cathodic) BasedBased onon thisthis concept,concept, ththee averagaveragee experimentalexperimental currencurrentt efficiencyefficiency isis calculatecalculatedd forfor threethree setsetss ooff experiments.experiments. SIMMERSIMMER (Simulator(Simulator forfor IntegratedIntegrated MetallurgicalMetallurgical andand MaterialsMaterials ElectrochemicalElectrochemical ReactionReaction)) software,, developeddeveloped iinn ththee DepartmenDepartmentt ooff MetallurgicalMetallurgical EngineeringEngineering wawass usedused ttoo calculatcalculatee ththee theoreticatheoreticall currencurrentt efficiency.efficiency. TheThe softwaresoftware interfaceinterface windowindoww iiss shownshown inin FigurFiguree 3.133.13.. ThisThis softwaresoftware cacann simulatesimulate potentiodynamipotentiodynamicc scascann resultresultss forfor 5252 ~ SIMMERSIMMER (Simulator(Simulator forfor IntegratedIntegrated MetallurgicalMetallurgical andand MaterialsMaterials ElectrochemicalElectrochemical Reactions)Reactions) GJ[Q)f-~]f5 [gJ| X GrapGraphh LimitsLimits SpeciesSpecies 2.5e0 InformationInformation LogfLogXlX minmin (A/m2lJ (A/m2) ) r-r--IT3LogfLogXlX max (A/m2lJ(A/m2) J J7*~ Y min mi n(Volt [voltss) ] ~rZ5 Y max ma x(Volt (Voltss) ) F5" ElectrodElectrodee ReactionReactions ReferencReferencee PointsPoints (lNhite(White Squares)Squares) lologg Iii|i |(A/m2) (A/m2 ) Y (Volt (Voltss) ) logliloglill (A/m2)(A/m2 ) Y (Volt (Voltss) ) ExperimentaExperimentall 1|o0 1jo0 1F0 ~ 10 Conditions E(V) Id 1jo0 1|o0 1[05 1lo0 SuSurfactanrfactantt 1!o0 1lo0 1lo""0 ' 1|o0 InformatioInformationn 1|0 1fo0 1F0 ~ 1^0 ResolutioResolutionn M(V ) CalculatioCalculationn RangeRange M(V ) RunRun calculalioncalculation [D.OO1'10.001 lowerlimiitlower limit fT.5i-2.5 -2.5e0 fil ..e /graph/ graph 110.0000022 upperupper limitlim* |2.5 SaveSave OutputOutpu t -3. ~ Working Electrode Data (Colored Squares) Graph Working Electrode Data (Colored Squares) PotentialPotential CalculateCalculatedd Color ElectrochemicaElectrochemicall ReactionReaction Pot.. ntial M Rat.. (Alm2) 1-1. 81 e+OOO (V)(V) Rate(A/m2Rate (Alm2)) Potential (V) pi]71-0.0(7 Rate(A/m2) -1.81e+000 RedRed 1|lFe31 Fe3++ ++ 1 e1e--= =1 F e2+1Fe2 + 1jo0 1j-1.37e+00-1 .37e+001 CCountero unter ElectrodeEIectrode DataData (PointslThin(Points/Thin Une)Line) Blue 12H+ + 2e- = 2H2(aq) 10 14.90e+000 Pot.. ntial M r;;;;-7~ Rate(A/m2Rat.. (Alm2)) ljinsuffiinsuffic.c ratratee Blue |2H+ + 2e- = 2H2(aq) |o |4.90e+000 Potential (V) f Gr ....n 14H+ + 1 02(aq) + 4e- = 2H20 1-452e+001 CelCelll VoltageVoltage Green )4H+ + 102(aq) + 4e- = 2H20 1F0 ~ ]-4.52e+001 RelativRelativee toto CelCelll PowerPower Yelloy ..llow w 1j1CuCI21 CuCI2- ++ 1 e-1e=- 1= Cu 1C +u 2CI + 2CI- 10 1]4.90e-004.90e-0011 WorkinWorkingg Electr_Electr . DensityDensity OpenOpen CircuitCircuit Pot._ (V)(V) (W/m2) PotentiaPotentialMl (V) OrangeOrange 1|1CU21 Cu2++ + 2e 2e-- == 1 Cu1C u 1fo0 1J3.17e+003.17e+0011 (W/mZ) PurplPurplee 1|1CU1 Cu+ ++ 1 1e e- -= =1 Cu 1C u 1fo0 1|3.27e-003. 27e-0033 llououtt ofof rangerange l[outoout off ranranggee 1j-0.082-008288 FigureFigure 3.133.13:: SIMMERSIMMER window.window. 5353 sixsix simultaneoussimultaneous electrochemicaelectrochemicall reactionreactionss inin ththee systemsystem.. IItt requirerequiress ththee followinfollowingg inputinput forfor simulationsimulation:: aa.. ConcentrationConcentration andand chargecharge forfor eaceachh ioniionicc speciesspecies ooff importanceimportance bb.. DiffusivitDiffusivityy ooff ioniionicc speciesspecies c.c. ForwardForward andand backwarbackwardd reactioreactionn constanconstantt valuevaluess foforr eaceachh ofof reactionreaction d.d. ThermodynamiThermodynamicc datdataa forfor eaceachh speciesspecies e.e. TotalTotal solutionsolution resistanceresistance ff.. AngulaAngularr velocitvelocityy ofof rotatinrotatingg disdiscc electrodeelectrode g.g. WorkinWorkingg electrodeelectrode potentiapotentiall witwithh respecrespectt ttoo SHESHE ConcentratioConcentrationn ooff eacheach ioniionicc speciesspecies isis calculatecalculatedd fromfrom VisuaVisuall MinteMinteqq softwaresoftware.. DiffusivityDiffusivity ooff ionicionic speciespeciess iiss taketakenn fromfrom variouvariouss sourcessources [1-17].[1-17]. TotalTotal solutionsolution resistancresistancee forfor eacheach electrolyteelectrolyte isis calculatedcalculated usinusingg electrochemicaelectrochemicall impedanceimpedance spectroscopy.spectroscopy. A defaultdefault symmetrysymmetry factorfactor wawass chosenchosen foforr simulationsimulation.. RatRatee constantsconstants foforr reactionreactionss areare determineddetermined usinusingg a sensitivitysensitivity analysisanalysis.. WorkingWorking electrodelectrodee potentiapotentiall witwithh respecrespectt toto ththee standarstandardd hydrogenhydrogen electrodeelectrode (SHE(SHE)) iiss calculatecalculatedd frofromm potentiodynamipotentiodynamicc scanscanss iinn actuaactuall electrolyteelectrolyte.. ThiThiss softwaresoftware iiss designedesignedd forfor rotatinrotatingg disdiscc electrodeelectrode experimentsexperiments.. HoweverHowever,, alalll factorialfactorial desigdesignn experimentsexperiments werweree conducteconductedd usinusingg paralleparallell platplatee electrodeselectrodes.. TheThe rotatinrotatingg discdisc electrodelectrodee equivalenequivalentt angularangular velocitvelocityy forfor paralleparallell platplatee electrodeelectrodess wawass estimatedestimated bbyy equatinequatingg SherwooSherwoodd numbers.numbers. ThThee SherwoodSherwood numbenumberr foforr rotatinrotatingg disdiscc electrodeelectrodess cancan bbee expressedexpressed aass showshownn iinn equationequation [3.36][3.36] [19-22].[19-22]. o.ss0 5 0.330 33 S h( rotating disc) —= C R eroatating disc uJ c J where C = 0.616 [3.36] ^h(rotating disc) C Reroatatingdlsc SC^ where C = 0.616 [3.36] 5454 Similarly,Similarly, forfor paralleparallell platplatee electrodeselectrodes SherwoodSherwood numbenumberr cacann bbee expressedexpressed asas equatioequationn [3.37][3.37] [19-22].[19-22]. S 0.33 e / S = CR 0.33 (d 3)0.33 [3.37] ShWhpp =CRj^Srf/.W c ~xf [3.37] wherwheree de e = 2 x ChanneChannell heighheightt (channe(channell heighheightt ~ 1cm)1 cm) Xx = flofloww widtwidthh (i(inn paralleparallell platplatee electrodeelectrode useusedd iinn experimentexperiment spacingspacing iiss kepkeptt = 1 cm)cm) C == 1.8491.849 [20-22][20-22] 4 RepReppp == ReynoldReynoldss NumbeNumberr (fo(forr paralleparallell platplatee electrodeelectrode)) == 2.2.00 xx 10104 Schmidt Number can be expressed as Schmidt Number can be expressed as Sc = Schmidt Number = Kinematic Viscosity/Diffusivity Sc = Schmidt Number = Kinematic Viscosity/Diffusivity For water based solution Schmidt number can be assumed to be 1000 [12-15] For water based solution Schmidt number can be assumed to be 1000 [12-15] 2 ReynoldsReynolds numbenumberr = ReRerotatingdirotating disscc = r ww/ul fl. (fo(forr rotatinrotatingg disc)disc) wherwheree r = radiuradiuss ofof discdisc;; w = angulaangularr velocityvelocity;; fl|i = kinematikinematicc viscosityviscosity AssumptionsAssumptions:: • KinematiKinematicc viscositviscosityy isis assumeassumedd constantconstant • ReynoldsReynolds numbenumberr iiss assumeassumedd constantconstant 5555 • ReynoldsReynolds numbernumber forfor rotatingrotating discdisc electrodeelectrode isis a functionfunction ofof radiusradius squaredsquared whichwhich cancan bbee calculatecalculatedd bbyy equatinequatingg ththee discdisc areareaa ttoo thathatt ooff actualactual areareaa exposeexposedd iinn electrolyte.electrolyte. BByy equatinequatingg ththee SherwooSherwoodd numbenumberr forfor thesthesee casescases,, anan equivalenequivalentt angularangular velocitvelocityy ooff rotatingrotating disdiscc electrodelectrodee cancan bbee writtewrittenn aass equatioequationn [3.38].[3.38]. 2 lOOOxZ) 1.86 OJ= 1000XD[~]2 x[R X2]O.660M co- x[Rex2] [3.38][3.38] r2 0.610.6166 e 11 2 44 ((0D = 10-10"" mm2/s,/s, RRce = 2.2.00 x 10 ,, radiuradiuss equivalenequivalentt isis calculatecalculatedd bbyy equatingequating area)area) EquatioEquationn [3.38][3.38] assumesassumes aann averageaverage angulaangularr velocitvelocityy equivalentequivalent forfor ththee paralleparallell plateplate electrodelectrodee case,case, whicwhichh wawass estimatedestimated ttoo bbee 1.61.6 radian/sec.radian/sec. StepsSteps ttoo obtainobtain simulatesimulatedd potentiodynamipotentiodynamicc scanscan resultsresults andand currencurrentt efficiency:efficiency: l.1. WorkingWorking electrodeelectrode potentiapotentiall iiss entereenteredd iinn ththee inpuinputt windowindoww (Figur(Figuree 3.13).3.13). AlAlll otherother inputinputss areare kepkeptt aatt defauldefaultt values.values. 22.. BByy clickingclicking ththee speciespeciess informatioinformationn icon,icon, anotheranother windowindoww (Figur(Figuree 3.14)3.14) opensopens,, wherewhere alalll ioniionicc species,species, theitheirr diffusiodiffusionn constanconstantt anandd chargecharge oonn eacheach ioniionicc speciesspecies areare entered.entered. 33.. BByy clickinclickingg ththee electrodeelectrode reactioreactionn windowwindow anotheranother windowindoww (Figure(Figure 3.153.15)) appearsappears wherwheree alalll detaildetailss ofof electrochemicaelectrochemicall reactioreactionn anandd anodianodicc /cathodi/cathodicc reactioreactionn constantsconstants areare entered.entered. 44.. AnodiAnodicc anandd cathodicathodicc reactioreactionn constantsconstants araree entered.entered. 5.5. BByy clickinclickingg ththee experimentaexperimentall condition conditionss icoiconn anotheanotherr windowwindow (Figure(Figure 3.16)3.16) appearsappears wherwheree informatioinformationn relaterelatedd ttoo angulaangularr velocitvelocityy andand totatotall solutiosolutionn resistancresistancee areare entered.entered. 6.6. BByy clickingclicking ththee rurunn icoiconn outputoutput wilwilll appeaappearr iinn ththee firstfirst windowindoww iinn ththee formform ofof thethe totaltotal summedsummed ratesrates ooff reactionreaction,, individuaindividuall ratesrates,, anandd currencurrentt efficiencyefficiency cacann bbee calculated:calculated: 5656 Species Data Input Retrieve Input Data Save Input Data StStdd FreFreee EnEn AdsAds.. Cons!.Const . DiffusivitDiffusivityy NamNamee molalitmolalityy (m)(m ) ActivitActivityy Coel.Coef . (J/mol(J/mol)) WorkinWorkingg EI.El . ChargChargee (m2/sec)(m2/sec) SpeciesSpecies AA jFe2Fe2++ 10.084008477 11 1I-7887-788700 11 12 10.000000000.0000000011 SpeciesSpecies 8B IFe3Fe3++ 1 0.002630.0026~) 11 1-4600•4600 11 1(3 10.0000000000.00000000088 SpeciesSpecies C IFFee 11 11 10. 11 ro--l0 0.0000000000.o.o.o.o.o.o.o.o.o.11 SpeciesSpecies D IHH+ + 10.235G32G20.2356326211 11 10. 11 r;--11 0.0000000090.o.o.o.o.o.o.o.o.933 SpeciesSpecies E 102(aq)02(aq) 10.00130. ·001333 11 111640640.00 11 1o0 10.0.0.0.0.0.0.0.0.2260.00000000226 SpeciesSpecies F H2H2O0 11 11 1-•237142371411 11 ro-l0 0.0000000022o.·o.o.o.o.o.o.o.o.2244 SpeciesSpecies G IH2(aqH2(aq)) 10.000820.0.00.8222 11 11760017600 11 1o0 10.000000000.·0.0.0.0.0.0.0.0.33 Species H 10H-OH- 10.000000000.0.00.0.0.0.0.00.0 11 1-157328-157328 11 1--11 10.00000000520.·0000.0.0.0.05255 ·SpeciesSpecies I1 IcuCu 11 11 1io0. 11 ro---l0 0.000000000o.·o.o.Oo.o.o.o.0011 SpeciesJSpecies J ICu2+Cu2+ 10.0078860.00788666 11 1J6552655200 11 12 10.0.00000000007·0.0.0.0.0.0.0.0.0.0.711 SpeciesSpecies K IZn2Zn2++ 11 11 11-14726-1472600. 11 ~ 10.000000000.·000.0.0.0.0.0.11 SpeciesSpecies LL jCu+Cu+ 10.00000500.0.00.0.0.50.33 11 1499849980.0 11 ~1 10.000.0.0.0.0.0.0005300000000000053 SpecieSpeciess M IS042-SD42- 11 11 1|-74463-744630.0 11 1•-22 10.000000000.·00.0.0.0.0.0.0.11 SpeciesSpecies N jNaNa++ 11 11 1-26190-26190.0.0 11 ~1 10.0.0.0.0.0.0.0.0.10.000000001 SpecieSpeciess 0 CICI-- 10.340.3488 11 1i-131270. -131270 11 1-1 110.00000000200. 0.0.0.0.0.0.0.0.20.33 FigurFiguree 3.143.14:: SIMMERSIMMER speciesspecies datdataa input.input. 5757 y| •(§ pel SpeciesSpecies IIdentitie denti1iess 'INW C 0o 0 R U A: B: KKIl N * |Fe2jFe2+* B: I|Fe3Fe3++ C I|FFee D: IH+jH + E: 1|02(aq02(aq)) N T G E F: : |H2IH200 G: I|H2(aqH2(aq)) HH:: JOH10H-- l: I: jCIucu JJ:: I|Cu2Cu2++ E R L E fcK: |Zn2IZn2+t LL:: I|Zznn M:: 1[s0425042-- N:: IJNNa+ 0: I[ciCI-- E L a+ C E T Cc R T o0 R ElectrochemicalElectrochemical ReactionsReactions D 0 E D E AnoAnodd CatCathh E EExamplxamplee ReaReactionction:: 1A + 2BB + 2e2e-- = 2C2C + D AlphAlphaa AlphAlphaa RxR~nn RxR~nn Ca(Cathh AnoAnodd ConConsst ConsConst 1, I1fBn is" +* Ir~ Ir *+ r rr *+ rrr*F"*-mmm r +11 e- = rIA +rr +rl +rrm fO"5J0.5 |05fD.5 fki8|le18 1|0.0020 . 00~i pP r 2FF11fT* +f2FP*rr ro + r 1* + rrr*mmmmF"i r + r e- = II+ II + II + PINN fO"5|0.5 |l.f1:55 fk8|le8 ~10 r r 3 f4fD + Fif*rrr;- IE + r r- + rmr--FF r +f4 e- = f21F <+'Imrr + rr < +r,r r fO"5J0.5 f1.5jlj 1|000000000000 /4e24|4e24 r Pp 4 flIN + Irr-rr r + r r- + rrr.mmmFT'F r +r e- = II+ II + rrt +f210 ? fO"5J0.5 |0.jD.5"5 f12OO"11200 fD.06110.001 Pp r ~ flfT + Im I + mr r + rrr^-mmmr r + f2 e- = rll +rr +Ir + rrr ID.5|0.5 |0.jD.5"5 110.070.0722 ro.onJ0.072 pP r E FTf1fL* + Irr*rr r + r r* + rrr*mmmm r + f1 e- = 1111 +Ir + 'I + mIr [D.5J0.5 \D.5|0.5 res|le8 res|le8 p9 r 4 FigurFiguree 3.153.15:: SIMMERSIMMER electrochemicaelectrochemicall reactioreactionn input.input. 5588 P~i ExperimentaExperimentall ConditionConditionss DatDataa EntrEntryy PanePanell El?GJ[Q)~! RotationaRotationall VelocityVelocity (RPM)[RPM ] 14S4800 o ReferencReferencee ElectrodElectrodee 10 Potentiall (V)(V) BoundarBoundaryy LayerLayer ThickneThicknessss (m(m)) (default(defaults toto internal interna l I calculatiocalculationn iiff leftleft blank)blank) ElectrodElectrodee AreaArea (m2)(m2 ) |0.0004210.0004266 IoniIonicc StrengthStrength (defaults(defaults toto internainternall calculationcalculation ifif leftleft I blankblank)) KinematiKinematicc ViViscositscosityy (m2/(m2/secsec)) (default(defaultss ttoo purepure waterwater value value I (0.000001(0.000001)) atat 40C4oC ifif left lef t blankblank)) EstimateEstimatedd UncompenUncompensatesatedd SolutioSolutionn ResistancResistancee (Ohms)(Ohms) 1|11 OtheOtherr ReResistancsistancee |o0 (Ohms(Ohms) 1 A FigurFiguree 3.163.16:: SIMMESIMMERR experimentaexperimentall conditionconditionss inpuinputt window.window. 5959 _. • , ^ r-r- • SumSum ooff individuaindividuall rates(Cu)rates(Cu) Theoretical Current efficiency = [3.39] Theoretical Current erriciency = Total rate of reaction [3.39\ Total rate of reaction ForwardForward andand backwarbackwardd reactioreactionn constantconstantss useusedd inin thithiss simulationsimulation areare determineddetermined bbyy fittingfitting potentiodynamipotentiodynamicc scanscan datdataa witwithh SIMMERSIMMER datdataa assisteassistedd bbyy a sensitivitsensitivityy analysis.analysis. InitiallyInitially,, thethe valuvaluee ooff thesthesee constantsconstants areare chosechosenn closclosee ttoo ththee individuaindividuall reactioreactionn constanconstantt foforr singlesingle reactionsreactions,, bubutt foforr complexcomplex mixemixedd reactioreactionn systems,systems, ththee valuevaluess werweree alteredaltered.. SIMMERSIMMER softwarsoftwaree wawass rurunn usinusingg defauldefaultt valuevaluess anandd totatotall currents.currents. CurrentCurrent efficiencyefficiency isis calculatedcalculated usinusingg thesthesee valuesvalues.. BecausBecausee ofof complecomplexx reactioreactionn systems,systems, valuevaluess obtainedobtained dodo nonott matcmatchh wellwell withwith experimentaexperimentall currencurrentt efficiencyefficiency untiuntill appropriateappropriate adjustmentadjustmentss areare mademade.. A newnew simulatiosimulationn iiss thethenn performeperformedd anandd adjustmentadjustmentss ttoo kkaa anandd kkbb areare madmadee untiuntill ththee differencedifference betweebetweenn experimentalexperimental andand simulatedsimulated currencurrentt efficiencies,efficiencies, anandd experimentalexperimental andand simulatedsimulated currencurrentt densitydensity,, areare withiwithinn 1010%% forfor mosmostt teststests.. AssociateAssociatedd constanconstantt valuevaluess areare listelistedd iinn TableTable 3.23.2.. BaseBasedd onon reactioreactionn constanconstantt valuesvalues,, currencurrentt efficiencefficiencyy iiss calculated.calculated. TotaTotall currentcurrent (rate(rate ofof reactionreaction)) iiss alsalsoo calculatecalculatedd andand comparecomparedd witwithh experimentalexperimental valuevalue.. A sensitivitsensitivityy analysianalysiss isis dondonee forfor k valuevaluess whicwhichh araree lOlOxx greategreaterr oror leslesss thathann assumeassumedd selectedselected values.values. FigureFiguress 3.13.177 anandd 3.183.18 suggestsuggest thathatt assumeassumedd kkaa anandd kkbb valuevaluess araree betterbetter thathann higherhigher oror lowelowerr valuesvalues testetestedd iinn sensitivitysensitivity analysisanalysis becausbecausee thetheyy givgivee ththee besbestt fit witwithh experimentalexperimental data.data. ThThee currencurrentt efficiencefficiencyy andand totatotall currencurrentt iiss alsalsoo calculatecalculatedd andand shownshown inin FigureFiguress 3.173.17 andand 3.183.18 forfor one-tentone-tenthh anandd tenfoltenfoldd multiplemultipless ooff ththee besbestt fittingfitting k valuvaluee ttoo illustrateillustrate ththee sensitivitysensitivity ooff ththee responsresponsee variablvariablee ttoo changeschanges iinn k valuevalue.. DetailDetailss ooff variouvariouss parametersparameters,, diffusiondiffusion coefficient,coefficient, kkbb anandd kkaa valuesvalues,, solutiosolutionn resistanceresistance,, andand symmetrysymmetry factorsfactors,, araree tabulatetabulatedd IIIin AppendiAppendixx AA.. ThThee totatotall ratratee ofof reactioreactionn anandd ththee ratratee ooff individuaindividuall electrochemicalelectrochemical reactionsreactions 6600 TableTable 3.2:3.2: ForwardForward andand backwarbackwardd constanconstantt valuesvalues,, estimateestimatedd bbyy sensitivitysensitivity analysisanalysis ka kkbb ElectrochemicalElectrochemical ReactionReaction 1 1 (MoleU'S"(MoleL-'S-')) (MoleL/'S"(MoleL-1S- )) 18 18 0.000.0022 33+ 22+ 1lxlO x 10 Fe + + ee-- -~> FeFe + s8 1010 + 11x10 X 10 2H+ + 2e-2e" -~> HH22 24 1 24 + 1 4xl04 X 10 4H+ + 02 + 4e4e-" -~> 2H2H22O0 12001200 0.0010.001 CuClCuCb-2~ + e~^Ce- ~ Cuu + 2CI2Cl 00.07.0722 0.0720.072 22+ Cu ++2e +2e'- ~-^C Cuu 88 88 1lxlO X 10 1lxlO X 10 Cu+ ++e- e" -~> CuCu 80 70 r o Expt r- • kl10 >. 60 ~ (J ok c FigureFigure 3.17:3.17: ExperimentaExperimentall andand theoreticatheoreticall currentcurrent efficiencefficiencyy anandd sensitivitsensitivityy analysisanalysis forfor differentdifferent KaKa values.values. 6161 9 8 o Expt . k r- r- 7 o kl10 010 k r- ~ 6 - 5 r- r- - r- c:: -~ 4 I: - r- r- r- <3 3 f0- r, 2 1 o ..... Cu01- Cu09Cu09-- Cu01 Cu01-- Cu09-Cu09- Cu01Cu01-- Cu09 Cu09-- Cu01-Cu01- Cu09Cu09-- 09Fe0109Fe01-- 01Fe01-01Fe01- 09Fe09-09Fe09- 01Fe09 01Fe09-- 09Fe01 09Fe01-- 01Fe01-01Fe01- 09Fe09 09Fe09-- 01Fe09 01Fe09-- 09H009H055 09H0 09H055 01H0501H05 01H0501H05 09H1 09H155 09H109H155 01H1501H15 01H1 01H155 TesTestt I10D FigurFiguree 3.183.18:: ExperimentalExperimental anandd theoreticatheoreticall currencurrentt densitydensity andand sensitivitsensitivityy analysianalysiss forfor differendifferentt KKaa vvaluesalues.. 6262 areare outputoutputss ooff SIMMER.SIMMER. AnAn E vsvs.. loglog (I(1)) grapgraphh cacann alsalsoo bbee plotteplottedd foforr alalll simulationsimulationss usingusing SIMMERSIMMER data.data. TheThe comparisoncomparison betweebetweenn twtwoo samplesampless ofof actualactual potentiodynamipotentiodynamicc scanscan anandd simulatedsimulated scansscans isis shownshown iinn FiguresFigures 3.13.199 andand 3.20.3.20. ItIt cacann bbee observeobservedd iinn FigureFiguress 3.13.199 andand 3.203.20 thatthat simulatesimulatedd currencurrentt anandd potentiapotentiall relationshirelationshipp matcmatchh reasonablreasonablyy welwelll witwithh experimentalexperimental potentiodynamipotentiodynamicc results.results. 3.4.23.4.2 AnalysiAnalysiss ooff ElectroplateElectroplatedd samplesample CharacterizationCharacterizationss ofof electrodepositedelectrodeposited samplessamples werweree performeperformedd bbyy imagimagee analysis.analysis. OneOne ofof ththee analyseanalysess iiss surfacsurfacee coveragecoverage ooff electrodepositedelectrodeposited coppecopperr foforr variouvariouss testestt conditions.conditions. ImagesImages ooff variousvarious samplessamples werweree evaluatedevaluated usinusingg ImageImage J softwaresoftware.. BByy usinusingg propeproperr thresholdthreshold adjustmenadjustmentt conditionconditionss a colocolorr imagimagee cancan bbee changechangedd intointo a blacblackk andand whitwhitee formaformatt anandd thethe percentagpercentagee ooff coveragcoveragee ofof blacblackk andand whitwhitee pixelpixelss cacann bbee calculatedcalculated.. HenceHence inin thithiss wayway percentagpercentagee coveragecoverage ooff surfacesurface cacann bbee calculated.calculated. _ _ totatotall areaarea ooff electrodelectrodee coverecoveredd bbyy electrodeposielectrodepositt .„ P ercentage 0 f coverage = ------''------''---- [3.40] Percentage or coverage = total area of electrode [3.40J total area of electrode PercenPercentt coveragecoverage ooff variouvariouss electrodepositedelectrodeposited samplessamples araree comparecomparedd andand showshownn inin FigureFigure 3.213.21.. PercentPercent coveragecoverage isis alsoalso comparedcompared witwithh currencurrentt efficiencefficiencyy inin FigurFiguree 3.22.3.22. ItIt cacann bebe observeobservedd thathatt simulatedsimulated currentcurrent andand potentiapotentiall relationshirelationshipp matcmatchh reasonablreasonablyy welwelll withwith experimentalexperimental potentiodynamipotentiodynamicc resultresultss foforr mosmostt cases.cases. 63 0.4 0.2 -0.4 b& log(l) FigureFigure 3.193.19:: ExperimentalExperimental andand simulatedsimulated currentcurrent andand potentialpotential relationshirelationshipp forfor testestt idid CuOl-09FeOl-09HOS.Cu01-09Fe01-09H05. DetailsDetails ofof experimentsexperiments areare listedlisted inin TableTable 2.2.2.2. -6* -+-ByBy SIMMESIMMERR _ ExperimentalExperimental 0.50.5 0.30.3 CL sur> LU -3.5-3.5 -0-0..3 -0.5-0.5 10g(l)log(i) FigurFiguree 3.20:3.20: ExperimentalExperimental andand simulatedsimulated currentcurrent andand potentiapotentiall relationshirelationshipp forfor testtest idid CuOl-09Fe09-01H1S.Cu01-09Fe09-01H15. DetailDetailss ofof experimentsexperiments areare listedlisted inin TableTable 2.2.2.2. 64 100 80 ;e-o Q) 60 C) ...IV 40 o~ u 20 o Cu01-Cu01- Cu09-Cu09- Cu01-Cu01- Cu09-Cu09- Cu01 Cu01-- Cu09-Cu09- Cu01 Cu01-- Cu09-Cu09- 09Fe0109Fe01-- 01Fe01 01Fe01-- 09Fe09 09Fe09-- 01Fe09 01Fe09-- 09Fe01-09Fe01- 01Fe0101Fe01-- 09Fe09-09Fe09- 01Fe09-01Fe09- 09H0509H05 09H009H055 01H0 01H055 01H0501H05 09H109H155 09H1509H15 01H101H155 01H1501H15 TestTest 10ID FigurFiguree 3.213.21:: ComparisonComparison ooff percentagpercentagee coverage.coverage. 60 50 • [ ] ] c~ 40 CD • 'u In 30 A C + • Cu01-09Fe01Cu01-09Fe01-09H05- 09H05 • Cu09-01Cu09-01Fe01 Fe01-09H05- 09H05 ~ Xx ::::I 20 ACu01-09Fe09D.. Cu01-09Fe09-01- 01H0 H055 0 Cu09-0Cu09-01Fe09 1 Fe09-01- 01H0 H055 •o Cu01-09Fe01Cu01-09Fe01-09H15- 09H15 10 • Cu09-01Cu09-01Fe0 Fe01-09H1 09H1 155 + Cu01-09Fe09-01Cu01-09Fe09- 01H1 H 155 -Cu09-01-Cu09-01Fe09 Fe09-01- 01H1 H155 0 0 2200 4400 6060 8800 100100 PercentPercent coveragecoverage FigurFiguree 3.22:3.22: ComparisoComparisonn ofof percentagpercentagee coveragcoveragee andand efficiency.efficiency. 6565 ItIt iiss observeobservedd thathatt minimuminimumm coveragcoveragee isis forfor highighh cupricupricc andand highighh ferriferricc ioionn concentration.concentration. IInn contrastcontrast,, maximumaximumm coveragecoverage iiss observeobservedd forfor ththee loloww cupriccupric andand lowlow ferricferric ionion combinationcombination.. ItIt iiss observeobservedd thathatt highighh coveragcoveragee isis obtainedobtained foforr highehigherr currencurrentt efficiencyefficiency casescases asas expected.expected. 3.4.33.4.3 FactoriaFactoriall desigdesignn analysianalysiss ofof experimentsexperiments A factorialfactorial designdesign matrimatrixx waswas designeddesigned iinn orderorder ttoo measurmeasuree effectseffects ofof threthreee variablevariabless (A,(A, B anandd CC)) oonn ththee desiredesiredd procesprocesss outpuoutputt variablevariable.. EighEightt experimentsexperiments araree requirerequiredd foforr a 3-factor,3-factor, 2-level2-level design.design. A representrepresentss ththee ratiratioo ofof cupricupricc anandd cuproucuprouss ionion,, B representrepresentss ththee ratiratioo ofof ferricferric anandd ferrousferrous ioionn andand C representrepresentss ththee HCHCI1 concentration.concentration. AAss AA,, BandB and C areare presumepresumedd toto bbee controllecontrolledd independentlyindependently,, testtestss werweree performeperformedd aatt twtwoo levellevelss (high(high anandd lowlow)) iinn ordeorderr toto determinedetermine ththee effecteffect ofof changchangee iinn levelevell ooff ththee variablevariable onon ththee output.output. IInn TablTablee 3.3,3.3, ththee highhigh levellevel iiss indicateindicatedd bbyy "+"+"" sigsignn anandd ththee lowlow levelevell bbyy "-"-"" signsign,, respectivelyrespectively.. HigHighh andand lowlow levelslevels forfor interactioninteractionss A witwithh BB,, A witwithh C,C, B witwithh C anandd A witwithh BBand and C araree representerepresentedd bbyy AB,AB, ACAC,, BBCC anandd ABCABC,, respectivelyrespectively.. TheThe relativrelativee effectseffects ooff suchsuch interactioninteractionss onon ththee observedobserved valuevaluess cancan bbee evaluateevaluatedd usinusingg thisthis approach.approach. FromFrom ththee resultresultss ofof ththee factoriafactoriall desigdesignn analysisanalysis,, iitt cacann bbee concludeconcludedd thathatt highhigh ferricferric toto ferrouferrouss ratiratioo hahass maximumaximumm adversadversee effecteffect onon electro-depositionelectro-deposition currencurrentt efficiency.efficiency. ThisThis effecteffect cacann bbee observedobserved visuallvisuallyy iinn FigureFiguress 3.23.233 anandd 3.243.24.. FigurFiguree 3.23.233 showshowss thathatt electrodepositionelectrodeposition aass welwelll aass surfacesurface coveragcoveragee iiss reducereducedd foforr electrolyteselectrolytes witwithh highighh (F(Fee 3+/Fe/Fe 2+).). HigHighh contentcontent ofof aciacidd aass welwelll aass highighh cupric/cuproucupric/cuprouss ratiratioo alsalsoo causecausess aann adverseadverse effecteffect onon electrodeposition/currenelectrodeposition/currentt efficiency.efficiency. 6666 TablTablee 3.33.3:: FactoriaFactoriall desigdesignn matrimatrixx outpuoutputt foforr experiments,experiments, discussediscussedd iinn sectionsection 2.4.3.2.4.3. RuRunn Cu22++/Cu/Cu+ Fe3+3lFeW2+ + HCHCI1 CurrenCurrentt ObserveObservedd TesTestt IDID A B C EfficiencEfficiencyy ValuValuee (%)(%) Cu01-09Fe01-09H0CuOl-09FeOl-09H055 1 - - - 5454 YYll Cu09-01FeOl-09H05Cu09-01Fe01-09H05 2 + - - 51.51.66 YY22 , Cu01-09Fe09-01H0CuOl -09Fe09-01 H055 3 - + - 3322 YY33 1 Cu09-01Fe09-01H0Cu09-01Fe09-01H055 4 + + - 2222 YY44 Cu01-09Fe01-09H1CuOl-09FeOl-09HI55 5 - - + 4477 YY55 Cu09-01Fe01-09H1Cu09-0 1F eO 1-09H 155 6 + - + 4040 YY66 Cu01-09Fe09-01H1CuOl -09Fe09-01HI55 7 - + + 2277 YY77 Cu09-01Fe09-01H1Cu09-0 1F e09-0 1H 155 8 + + + 2288 YY88 EffectEffectss ofof differendifferentt variablevariabless andand interactiointeractionn parameterparameterss are:are: 2 (A) =- (Cu2++/Cu/Cu+)) =-4.= -4.66 (effect(effect ofof variablvariablee A)A) 2 (B)(B) = (Fe3++//FeFe 2++)) = -20.9-20.9 (effect(effect ofof variablvariablee B)B) (C(C)) = (HC1(HCl)) = -4.-4.44 (effect(effect ooff variablvariablee C)C) (AB(AB)) = 0.0.11 (interactio(interactionn parameter)parameter) (AC(AC)) =1.= 1.66 (interactio(interactionn parameter)parameter) (BC(BC)) = 4.4.99 (interactio(interactionn parameter)parameter) (ABC(ABC)) = 33..9 (interaction(interaction parameter)parameter) MeaMeann = 37.737.7 6767 Test ID CuOl-09FeOl-09H05 Test ID Cu09-01FeOl-09H05 Test ID CuOl-09Fe09-01H05 Test ID Cu09-01Fe09-01H05 FigurFiguree 3.233.23:: ImagesImages ooff electroplatedelectroplated samplessamples,, testestt conditionconditionss areare representerepresentedd inin TableTable 2.22.2.. 6688 > TestTest IIDD CuOl-09PeOl-09H15Cu01-09Fe01-09H15 TesTestt IDID Cu09-01PeOl-09H15Cu09-01Fe01-09H15 —• TestTest IDID CuOl-09Pe09-01H15Cu01-09Fe09-01H15 TestTest IDID Cu09-01Pe09-01H15Cu09-01Fe09-01H15 FigureFigure 3.243.24:: ImageImagess ooff electroplateelectroplatedd samples,samples, testestt conditionsconditions araree representerepresentedd inin TableTable 2.22.2.. 6699 ThisThis trendtrend cancan bbee representerepresentedd inin FigurFiguree 3.253.25,, wherwheree iitt cancan bbee observeobservedd thathatt highighh currentcurrent efficiencyefficiency iiss associateassociatedd witwithh a loloww fcrric/ferrousferric/ferrous anandd cupric/cuproucupric/cuprouss ratiratioo combinationcombination.. ItIt hashas alreadyalready beebeenn reportereportedd thathatt electrolysiselectrolysis ofof cupriccupric chloridchloridee causescauses corrosiocorrosionn ofof coppercopper cathodecathode andand causescauses precipitatioprecipitationn ofof CuCCuCIl [13].[13]. ReductioReductionn iinn currentcurrent efficiencefficiencyy inin ththee presencpresencee ofof cupriccupric ioionn inin cuproucuprouss chloridechloride solutionsolution hahass alreadalreadyy beebeenn reportereportedd iinn thithiss study.study. A possiblepossible explanationexplanation forfor thethe reductioreductionn ofof currencurrentt efficiencyefficiency iiss ththee dissolutiodissolutionn ooff coppecopperr cathodcathodee inin presencpresencee ofof cupricupricc ionionss [13].[13]. CurrenCurrentt efficiencefficiencyy dropsdrops witwithh increasinincreasingg concentrationconcentration ooff ferricferric ionsions aass iiss evidenevidentt fromfrom factoriafactoriall desigdesignn experimentsexperiments aass welwelll aass simulation.simulation. PowerPower consumptionconsumption alsalsoo increaseincreasess witwithh increasincreasee iinn concentratioconcentrationn ooff ferricferric ionsions.. ThThee ratratee ooff ferriferricc ionion reductionreduction iiss limitelimitedd bbyy diffusiodiffusionn ofof ferricferric ionionss ttoo ththee electrodeelectrode surfacesurface.. ThThee standardstandard reductioreductionn potentiapotentiall foforr Fe33++/Fe/Fe212+ isis 0.70.777 V anandd thathatt forfor Cu2+ /C/Cuu iiss 0.34V0.34V.. Thus,Thus, whewhenn ferricferric ioionn iiss presenpresentt durinduringg electrowinning,electrowinning, reductioreductionn ooff ferriferricc ioionn taketakess placplacee firstfirst whicwhichh consumesconsumes mucmuchh ofof ththee currentcurrent.. ThesThesee ionsions reducreducee rapidlrapidlyy aass thetheyy diffusdiffusee ttoo ththee surface.surface. HighHigh dissolutiodissolutionn ooff cathodcathodee duduee toto chloridechloride ionion presencpresencee hahass alsalsoo beebeenn reportereportedd [13].[13]. HydrochloricHydrochloric aciacidd iiss a sourcsourcee ooff chloridchloridee ionsions,, anandd itit thereforthereforee hahass aann adverseadverse effecteffect oonn electroelectrowinnin winningg currencurrentt efficiency.efficiency. 3.53.5 AnalysiAnalysiss ofof electroelectrowinnin winningg testestt matrimatrixx IIII OutputOutput ofof testestt matrimatrixx IIII (Table(Table 2.42.4)) confirmsconfirms ththee resultresultss ooff factoriafactoriall desigdesignn experimentexperimentss asas discussediscussedd earlier.earlier. HigHighh ferricferric ioionn concentrationconcentration causescauses a reductioreductionn iinn currencurrentt efficiency.efficiency. WheWhenn ththee relativrelativee concentrationconcentration ofof ferrousferrous ioionn increases,increases, currentcurrent efficiencefficiencyy alsoalso increasesincreases.. OnOn ththee otherother handhand,, highighh cuproucuprouss andand lowlow ferricferric ioionn combinationcombinationss resulresultt inin maximumaximumm efficiency.efficiency. FigurFiguree 3.263.26 representrepresentss currentcurrent efficiencefficiencyy foforr eaceachh experiment.experiment. 70 21>1>(3_0)2**(3-0) designdesign . >70 . <70 . <60 D <50 0<40 . <30 . <20 '0 Figure 3.25: Contour plot of current efficiency vs. different variables. 7711 70 ~ 60 " >. (.) 50 r::: .~ (.) 40 ;;::: -w 30 -r::: ... Test 10 FigurFiguree 3.26:3.26: CurrenCurrentt efficiencyefficiency isis plotteplottedd foforr eacheach TesTestt IIDD basebasedd oonn testtestss anandd conditioncondition inin TableTable 2.32.3.. CurrentCurrent efficiencefficiencyy resultresultss cancan bbee correlatedcorrelated witwithh ferriferricc ioionn concentration.. FigurFiguree 3.273.27 showsshows currentcurrent efficiencyefficiency decreasesdecreases asas a functiofunctionn ooff increasingincreasing ferricferric ioionn concentration.concentration. AccordinAccordingg ttoo resultresultss ofof factorialfactorial desigdesignn experimentsexperiments highighh cupric/cuproucupric/cuprouss ratiratioo alsoalso causescauses anan adversadversee effeceffectt oonn electroelectro-- deposition/currendeposition/currentt efficiencyefficiency.. ThiThiss iiss evidentevident frofromm FigureFigure 3.28,3.28, whicwhichh showshowss anan increasincreasee inin concentratioconcentrationn ooff cupriccupric ionion thathatt iiss associateassociatedd witwithh ththee reductionreduction inin currencurrentt efficiency.efficiency. 7272 60 50 ~ ~ ~ 40 r:: CI) 'ij IE 30 w ...r:: ...CI) 20 ::::I y = -4238.1x2 - 6,1905x + 50 0 10 R2 = 1 0 I 1 1 1 1 1 1 0 0.020.02 0.040.04 00.0.066 0.080.08 00..11 0.120.12 ConcentratioConcentrationn ooff FerricFerric IonIon (mole/I)(mole/I) FigurFiguree 3.273.27:: CurrentCurrent efficiencefficiencyy isis plotteplottedd foforr differentdifferent ferriferricc ioionn concentration.concentration. 6060 5500 >- (.) c: 40 ,~ (.) ;;::: -CI) 30 c: -CI) .... ::J 20 U 10 0 > 1 1 1 VerVeryy lowlow VeryVery high high CuprouCuprouss ionion ttoo cupriccupric ionion ratioratio FigurFiguree 3.28:3.28: CurrentCurrent efficiencyefficiency iiss comparecomparedd foforr cuprouscuprous ioionn ttoo cupricupricc ioionn ratioratio (lo(loww forfor testestt IIDD CulO-OOFeOO-0CulO-OOFeOO-OO0 anandd highighh forfor testestt IIDD CuOO-lOFeOO-OO).Cu00-10Fe00-00). CHAPTECHAPTERR 4 CONCLUSIONCONCLUSIONSS ReasonablReasonablee infonnationinformation regardinregardingg ththee effectseffects ooff FFee 3+,, FeFe 2+ , CuCu 2+,, CCu+u andand hydrochlorichydrochloric acidacid concentratioconcentrationn onon chalcopyritchalcopyritee ororee leachinleachingg asas welwelll asas electrowinninelectrowinningg ofof coppercopper usingusing chloridchloridee medimediaa hahass beebeenn detennineddetermined anandd modelemodeledd inin thisthis study.study. IntegratioIntegrationn ofof leachingleaching chalcopyritechalcopyrite oreore anandd electrowinningelectrowinning ooff coppercopper waswas carriedcarried ououtt usinusingg calciucalciumm chloridchloridee andand cupriccupric chloridchloridee aatt acidicacidic ppHH levelslevels,, (hydrochloric(hydrochloric aciacidd iiss used)used).. ThThee resultresultss indicatindicatee suchsuch anan integratedintegrated processprocess,, whicwhichh coulcouldd potentiallpotentiallyy reducreducee energenergyy consumptioconsumptionn oveoverr currentcurrent commercialcommercial hydrometallurgicahydrometallurgicall technologietechnologiess aass welwelll asas reducereduce cellcell voltagvoltagee anandd currencurrentt inin electrowinning,electrowinning, mamayy bebe possible.possible. BaseBasedd onon ththee rangrangee evaluatedevaluated iinn thithiss study,study, goodgood recoverrecoveryy ofof coppecopperr durinduringg leachinleachingg isis feasiblfeasiblee aatt hydrochlorihydrochloricc acidacid anandd cupriccupric ioionn concentrationsconcentrations ooff 0.150.15 mole/molell1 andand 0.00.099 mole/lmole/1 respectively.respectively. FactoriaFactoriall designdesign experimentsexperiments analysisanalysis showedshowed weaweakk signsignss ofof a smallsmall negativenegative effeceffectt ooff ferric/ferrouferric/ferrouss ionion ratiratioo oonn recovery.recovery. ElectrowinninElectrowinningg ofof coppercopper fromfrom chalcopyritchalcopyritee oreore usinusingg chloridechloride medimediaa wawass shownshown ttoo bebe possiblpossiblee atat loloww acidacid (0.0(0.055 mole/1molell)) concentratioconcentrationn anandd lowlow cupricupricc ioionn (0.0(0.011 mole/I)mole/1) concentrationconcentration.. HighHigh ferricferric ioionn concentratioconcentrationn hahass ththee maximumaXImumm adversadversee effecteffect onon electrowinningelectrowinning.. TheThe percentagpercentagee ofof electrodepositedelectrodeposited coveragecoverage areareaa (als(alsoo indicativindicativee ofof 7474 depositiodepositionn qualityquality)) iinn shorshortt testtestss wawass measuremeasuredd anandd foundfound ttoo bbee consistenconsistentt witwithh expectedexpected currentcurrent efficiencefficiencyy trendtrendss iinn mosmostt cases.cases. CurrenCurrentt efficiencefficiencyy valuevaluess simulatesimulatedd usinusingg SIMMERSIMMER softwarsoftwaree showedshowed googoodd agreementagreement witwithh (within(within 10%)10%) measuremeasuredd currentcurrent efficiencies.efficiencies. IInn addition,, simulatesimulatedd (SIMMER)(SIMMER) potentiodynamipotentiodynamicc scansscans werweree iinn googoodd agreementagreement witwithh measuremeasuredd data.data. APPENDIAPPENDIXX AA IMAGEIMAGESS OFOF ELECTROPLATEDELECTROPLATED SAMPLESSAMPLES 76 FigurFIguree AlAI:: ImageImage of electroplatedelectroplated samplesample (Test(Test FigurFiguree A2A2:: ImagImagee ofof FigureFigure A3A3:: ImagImagee ofof Id:: CulO-OOFeOO-OO)Cul0-00Fe00-00), electroplatedelectroplated samplesample electroplateelectroplatedd samplsamplee (Test(Test detailsdetails ofof experimentexperiment areare (Tes(Testt IdId:: CuOO- IdId:: CuOO-IOFeIOCu00-10Fel0-00)-OO), givegivenn inin TablTablee 2.4.2.4. 10Fe00-00)IOFeOO-OO),, detaildetailss ofof detailsdetails ofof experimenexperimentt areare experimentexperiment araree givengiven givegivenn iinn TablTablee 2.4.2.4. iinn TableTable 2.4.2.4. FigurFiguree A4:: ImagImagee ofof electroplatedelectroplated samplesample (Test(Test IdId:: CuOI-09Fe05Cu01-09Fe05-05)-05), detaildetailss ooff experimenexperimentt areare givengiven iinn TablTablee 2.4.2.4. FigurFiguree A5A5:: ImagImagee ofof FigurFiguree A6:: ImageImage ofof FigurFiguree A7:: ImagImagee ofof electroplateelectroplatedd samplsamplee (Test(Test electroplatedelectroplated samplesample (Test(Test electroplatedelectroplated samplesample (Test(Test Id:: CuOO-IOFeOO-03)Cu00-10Fe00-03), Id:: CuOO-IOFeOO-OI)Cu00-10Fe00-01), Id:: CuOOCu00-10Fe03-00)-IOFe03-00), detaildetailss ofof experimenexperimentt areare detaildetailss ooff experimenexperimentt areare detaildetailss ooff experimenexperimentt areare givengiven iinn TablTablee 2.4.. givengiven iinn TablTablee 2.4.. givegivenn iinn TablTablee 2.4.. 77 FigurFiguree A8A8:: ImagImagee ofof FigurFiguree A9A9:: ImagImagee ofof FigurFiguree A10AIO:: ImagImagee ofof electroplatedelectroplated samplesample (Tes(Testt Id:Id: electroplateelectroplatedd samplsamplee (Tes(Testt Id:Id: electroplateelectroplatedd samplesample (Test(Test Cu00-10Fe01-00)CuOO-IOFeOI-OO),, detailsdetails ofof CuOO-IOFe05-05),Cu00-10Fe05-05), detailsdetails ofof Id:Id: Cu05-05Fe05-05), experimentexperiment araree givegivenn iinn TableTable experimentexperiment araree givengiven inin TableTable detaildetailss ooff experimenexperimentt areare 2.42.4.. 2.4.. givegivenn inin TableTable 2.4.2.4. FigurFiguree AllAll:: ImagImagee ofof FigurFiguree A12A12:: ImagImagee ofof FigurFiguree A13A13:: ImagImagee ofof electroplateelectroplatedd samplesample (Test(Test electroplateelectroplatedd samplesample (Tes(Testt Id:Id: electroplatedelectroplated samplesample (Test(Test Id:Id: Cu03-06Fe05-05),Cu03-06Fe05-05), Cu02-08Fe05-05),, detaildetailss ofof Id:: CuOCu01-09Fe05-05) I-09Fe05-05),, detailsdetails ofof experimenexperimentt areare experimentexperiment areare givegivenn iinn TableTable detaildetailss ooff experimenexperimentt areare givengiven inin TablTablee 2.4.2.4. 2.42.4.. givengiven iinn TableTable 2.4.2.4. APPENDIAPPENDIXBX B CONCENTRATIOCONCENTRATIONN OOFF IONIIONICC SPECIESSPECIES 7979 0.. 09 0..0 08 - •oC Cu01-09Fe0u01-09Fe01-09H051 -09H05 • CCu09-01Fe0u09-01 Fe01-09H051 -09H05 £~.... 0.. 0707 o• CCu01-09Fe09-01H0u01-09Fe09-01 H05 11:: o• CCu09-01Fe09-01H0u09-01 F e09-01 H055 i1 0o.06.0 6 .• CCu01-09Fe0u01-09Fe01-09H151 -09H15 •1:1 CCu09-01Fe0u09-01 Fe01-09H151 -09H15 ~f 0o. 0505 • CCu01-09Fe09-01H1u01-09F e09-01 H155 Ii.... „ o• Cu09-01Cu09-01Fe09-01H1 Fe09-01 H155 ::s 0.0. 04 4) ~ ;:;1 0.00 03 u 00.02. 02 - 0.0011 o0 1L['1 an j - ruin , nj~i III i CuCCuCIl ((a<|01<1) CC11CIuCI++ CuCI2CuCI?--CCuCIuCI2? CuCI3 CuCI3- CuCuCI3-C13-22 CuCI4-CuCI4-?2 CC11OHuOH++ (aq(01<1)) FigureFigure BlBl:: ConcentrationConcentration ofof differentdifferent coppecopperr complexecomplexess iinn solutionsolution (determine(determinedd usingusing VisualVisual MinteqMinteq softwaresoftware)) foforr differendifferentt testestt IDsIDs,, detailsdetails ofof experimentsexperiments areare listelistedd iinn TableTable 2.22.2.. 0.000020.0000255 -, ^ 0.000020.00002 •C Cu01-09Fe01-09HOSCu01-09Fe01-09H05 -;-0) ...u • CU09Cu09-01Fe01-09H0-01 Fe01-09HOS5 ::::*i I-CIJ o• Cu01-09Fe09-01Cu01-09Fe09-01H0 HOS5 '0 o CU09-01 Fe09-01 HOS EI 00.00001.0000155 • Cu09-01Fe09-01H05 'E'~c • Cu01-09Fe01-09H1SCu01-09Fe01-09H15 .02 ;;*•> •C CU09-01Cu09-01Fe01-09H1 Fe01-09H155 nI ... 0.00001 • Cu01Cu01-09Fe09-01H1-09Fe09-01 H155 s:::: -ICIJ 0.00001 o Cu09-01 Fe09-01 H15 0 • Cu09-01Fe09-01H15 s:::: 0 Uo 0.000005 0 0.000005 0 Cu+1Cu+1 FigureFigure B2B2:: ConcentratioConcentrationn ooff cuprouscuprous ionionss inin solutionsolution (determine(determinedd usinusingg VisuaVisuall MinteqMinteq software)software) foforr differentdifferent testestt IDsIDs,, detaildetailss ooff experimentsexperiments areare listelistedd iinn TablTablee 2.2.2.2. 8800 0 .08 0 .07 • Cu01-09Fe01-09H05Cu01 09Fe01-09H05 Q) ... 0.06 •• CU09-01Cu09 01Fe01-09H0 Fe01 -09H055 ::::::~ Q) o• Cu01-09Fe09Cu01 09Fe09-01H0-01 H055 '0 0 .05 o CU09-01 Fe09-01 H05 E • Cu09 01Fe09-01H05 C •• Cu01-09Fe01-09H15CuOt 09Fe01-09H15 0 0.04 :;::; o• Cu09-01Fe01-09H15Cu09-01Fe01-09H15 co ... • Cu01-09Fe09-01Cu01- H15 s::: 0 .03 09Fe09-01H15 -Q) o• CU09-01Cu09 Fe09-01 H15 () 01Fe09-01H15 s::: 0 0.02 () 0 .01 0 Cu+2Cu+2 FigureFigure B3:B3: ConcentrationConcentration ofof cupriccupric ionsions inin solutionsolution (determined(determined usingusing VisualVisual MinteqMinteq software)software) forfor differentdifferent testtest IDs,IDs, detailsdetails ofof experimentsexperiments areare listedlisted inin TableTable 2.2.2.2. 00.0.099 i 0.080.08 o• Cu01-09Fe01Cu01-09Fe01-09H0-09H055 -sQ)r 0.07o.07 -... • Cu09-01 Fe01-09H05 :::: • Cu09-01Fe01-09H05 -aQ) 00.0.066 •o Cu01-09Fe09-01Cu01-09Fe09-01H0 H055 '0 •o Cu09-01Cu09-01Fe09-01H0 Fe09-01 H055 SE 0.05 C 0 .05 • Cu01-09Fe01-09H15Cu01-09Fe01-09H15 0 :;::; o Cu09-01 Fe01-09H15 co 0.00 .044 • Cu09-01Fe01-09H15 ... • Cu01-09Fe09-01 H15 s::: • Cu01-09Fe09-01H15 -oQ) 0.030.03 o CU09-01 Fe09-01 H15 () • Cu09-01Fe09-01H15 s::: 0 O() 00.0.022 0.00.Q11 0 CuCI2CuCI2-- CuCICuCI22 (aq)(aq) FigurFiguree B4B4:: ConcentratioConcentrationn ooff differendifferentt chlorchloroo complecomplexx ooff coppecopperr iinn solutiosolutionn (determined(determined usinusingg VisuaVisuall MinteMinteqq softwaresoftware)) foforr differendifferentt testestt IDsIDs,, detaildetailss ooff experimentexperimentss araree listelistedd iinn TablTablee 2.22.2.. 811 0.000030 .0000355 0.000030.00003 •C Cu01Cu01- 09Fe01-09H0509Fe01-09H05 CIl j--:e 0.0000250.000025 • CU09Cu09- 001Fe01 1 Fe01-09H05-09H05 ~ CIl •o Cu01-09Fe09-01Cu01 09Fe09-01H0 H055 "'05 E •o CU09-01Cu09 01Fe09 Fe09-01-01H0 H055 £ 00.0000.000022 ~ • Cu01-09Fe01-09H15Cu01 09Fe01-09H15 ;0 C• CU09-01Cu09 01Fe01 Fe01-09H15-09H15 ...III 0.000015 1:2 0.000015 • Cu01-09Fe09-01Cu01 09Fe09-01H1 H155 CIl •o Cu09-01Fe09Cu09-01Fe0 9 --01H101H155 § 0.00000 .000011 (,) 0.0000050.000005 0 CuCI3-CuCI3- FigurFiguree B5B5:: ConcentratioConcentrationn ooff CuC^CuCh-" iinn solutionsolution (determine(determinedd usinusingg VisuaVisuall MinteqMinteq software)software) foforr differendifferentt testestt IDsIDs,, detaildetailss ofof experimentexperimentss areare listelistedd iinn TableTable 2.2.2.2. 0.000000080.00000008 0.00000000 .000000077 Cu01-09Fe01-09H05 Q) • Cu01-09Fe01-09H05 ?... 0.000000060.00000006 :t:jg • Cu09-01Fe01-09H05Cu09-01Fe01-09H05 ~ CIl •o Cu01-09Fe09Cu01-09Fe09-01H0-01H055 (5"5 00.0000000.000000055 o CU09-01 Fe09-01 H05 E, • Cu09-01Fe09-01H05 C • Cu01-09Fe01-09H15Cu01-09Fe01-09H15 o0 00.0000000.000000044 1 ; Oc CU09-01Cu09-01Fe01-09H1 Fe01-09H155 III2 ... • Cu01-09Fe09-01H15Cu01-09Fe09-01H15 1: 0.00000000 .000000033 CIl o• Cu09-01Cu09-01Fe09-01H1 Fe09-01 H155 o(,)c:: 0 0 .00000002 (,)o 0.00000002 o 0 .00000001 0.00000001 0 0 CuC14-2CuCI4-2 Figure B6: Concentration of CuCI/-2 in solution (determined using Visual Minteq software)Figure B6 for: Concentratio different testn IDs,of detailsCuCLj "of i nexperiments solution (determine are listed din usinTableg 2.2.Visua l Minteq software) for different test IDs, details of experiments are listed in Table 2.2. 82 00..1 0.090.09 _ 00.0.088 • Cu01-09Fe01Cu01-09Fe01-09H0-09H055 Q)a -... • CU09-01Cu09-01Fe01-09H0 Fe01-09H055 ~| 0.070.07 Q;o o• Cu01-09Fe09-01Cu01-09Fe09-01H0 H055 "0 o CU09-01 Fe09-01 H05 E| 00.0.066 • Cu09-01Fe09-01H05 l: • Cu01-09Fe01-09H15Cu01-09Fe01-09H15 0 0.05 :;:;§ 0.05 o• Cu09-01Fe01-09H15Cu09-01Fe01-09H15 ctS ...(0 0.04 • CUOCu01-09Fe09-01H1 1-09Fe09-0 1 H155 ...I: 4Q)= 0.04 o CU09-01 Fe09-01 H15 CJ • Cu09-01Fe09-01H15 I:c 0.03 0o uo 00.0.023 -I o 0.01 ° 0.02 0 0.01 Fe+2Fe+2 0 FigurFiguree B7B7:: ConcentrationConcentration ofof ferrouferrouss ionionss iinn solutiosolutionn (determined(determined usinusingg VisuaVisuall MinteqMinteq software)software) foforr differendifferentt testestt IDs.IDs. detailsdetails ofof eXDerimentsexoeriments araree listelistedd iinn TablTablee 2.2.2.2. 0.030.0355 0.03 HCu01-09Fe01-09H0Cu01-09Fe01-09H055 -Q) ... • Cu09-01Fe01-09H05 ~ 0.025 • Cu09-01Fe01-09H05 :::::: Q) •o Cu01-09Fe09-0Cu01-09Fe09-01H0 1 H055 "0 •o CU09-01Cu09-01Fe09-01H0 Fe09-01 H055 E 0.02 l: • Cu01-09Fe01-09H15Cu01-09Fe01-09H15 0 :;:; OCu09-01Fe01-09H1o Cu09-01Fe01-09H155 ctS 0.015 ... • Cu01-09Fe09-01H15Cu01-09Fe09-01H15 ...I: Q) o CU09-01 Fe09-01 H15 CJ • Cu09-01Fe09-01H15 I: 0.01 u0 0.005 0 Fe+Fe+33 FigurFiguree B8B8:: ConcentratioConcentrationn ooff ferriferricc ionionss iinn solutiosolutionn (determine(determinedd usinusingg VisuaVisuall MinteqMinteq softwaresoftware)) foforr differendifferentt testestt IDsIDs,, detaildetailss ooff experimentexperimentss araree listelistedd iinn TablTablee 2.22.2.. 8383 1.6E-091.6E-09 ^ 1.4E-091.4E-09 - CHCu01-09Fe01-09H0 Cu01-09Fe01 -09H055 Q) ... re ) 1.2E-091.2E-09 • Cu09-01Fe01-09H05Cu09-01Fe01-09H05 :!: li t Q;"a> o• Cu01Cu01-09Fe09-01H0-09Fe09-01 H055 '0o 11E-0 E-099 o• Cu09-01Cu09-01Fe09-01H0 Fe09-01 H055 E I: • Cu01-09Fe01-09H15Cu01-09Fe01-09H15 8E-108E-10 - 0 io n :;; o0CuO9-O1FeO1-O9H1 Cu09-01 Fe01-09H155 C'a a t ... • Cu01Cu01-09Fe09-01H1-09Fe09-01 H155 r::::: nt i 6E-106E-10 -Q) Cu09-01 Fe09-01 H15 0CD o• Cu09-01Fe09-01H15 r:::::cO 0o 4E-104E-10 - uO 2E-102E-10 0 - FeOH+FeOH+ FigureFigure B9:B9: ConcentrationConcentration ofof FeOH + ionsions iinn solutionsolution (determined(determined usingusing VisuaVisuall MinteqMinteq software)software) forfor differentdifferent testtest IDsIDs,, detailsdetails ofof experimentsexperiments areare listedlisted inin TableTable 2.22.2.. 00.00.0033 0.00250.0025 - -. • Cu01-09Fe01-09H0509H05 Q) :t:... • Cu09-01Fe01-09H0509H05 =:::: Q) 0 .002 []• Cu01-09Fe09-01H001 H055 '0 [] CU09-01 Fe09-01 H05 E • Cu09-01Fe09-01H05 C • Cu01-09Fe01-09H109H155 0 0 .0015 :;; m[J Cu09-01Fe01-09H15Cu09-01Fe01-09H15 ...C'a 1: • Cu01Cu01-09Fe09-09Fe09-01H101H155 gQ) 0 .001 []• Cu09Cu09--01Fe0 01Fe099 -01H1-01H155 0 U 0.0005 0 FeOH+FeOH+22 FigurFiguree B10BIO:: ConcentratioConcentrationn ooff FeOFeOHH 2+ ionionss iinn solutiosolutionn (determine(determinedd usinusingg VisuaVisuall MinteqMinteq softwaresoftware)) foforr differendifferentt testestt IDsIDs,, detaildetailss ooff experimentexperimentss araree listelistedd iinn TablTablee 2.22.2.. APPENDIAPPENDIXCX C EXPERIMENTALEXPERIMENTAL ANANDD SIMULATEDSIMULATED CURRENCURRENTT DENSITDENSITYY ANDAND CURRENTCURRENT POTENTIAPOTENTIALL RELATIONSHIPRELATIONSHIP FORFOR DIFFERENTDIFFERENT TESTSTESTS 85 -+-By• By SIMMER SIMMER —•-B-+-Byy SIMMERSIMMER 0.6 0.5 ___ Experimental __ Experimental 0.5 •Experimental • Experimental 0.4 0.0.33 0.2 -*.5 -4 -3.-3 .5 -3 -2.5 * -3.5-3.5 --33 -0.-0.55 - -0.6 fc*- 10g(l)log(i) FigurFiguree CIC1:: PotentialPotential VVss lologg |iIii| FigurFiguree C2C2:: PotentialPotential VVss loglog |iIi|i graphgraph forfor TestTest IIdd Cu09-0Cu09-01Fe01 1F eO 1-- graphgraph foforr TesTestt IdId Cu01-09Fe09-Cu01-09Fe09- 09H0509H05,, detaildetailss ooff experimenexperimentt areare 01H0501H05,, detailsdetails ofof experimentexperiment areare givegivenn iinn TablTablee 2.32.3.. givengiven inin TablTablee 2.32.3.. -6T6- -+-By SIMMER ~BySIMMER• By SIMMER 0.6 • By SIMMER ___ Experimental 0.0.44 _ •Experimental Experimental • Experimental 0.4 0.2 0.2 0.2 -3.5 -3 -A5 -0.6 -0.4 10log(l9(1)) FigurFiguree C3C3:: PotentialPotential VVss lologg |iIii| FigureFigure C4:C4: PotentialPotential VVss loglog |iIi|i graphgraph forfor TestTest IIdd Cu09-Cu09- graphgraph foforr TesTestt IdId CuOCuOl 1-- 01Fe09-01H0501Fe09-01H05,, detailsdetails ofof 09Fe01-09H05,09Fe01-09H05, detaildetailss ofof experimenexperimentt araree givegivenn inin TableTable experimenexperimentt areare givegivenn iinn TableTable 2.32.3.. 2.32.3.. 8866 __• By By SIMMER SIMME R -+-By• By SIMMER SIMMER 0.4 __ Experimental 0.50.5 ___• E Experimentaxperimental l • Experimental 0.3 0.2 0.3 H ~ Q w ~ 5 -4 -3.5 w -4.5 •1 -3.5-3.5 -3 -0.3-0.3 -0.4 -0.5-0.5 10g(l)log(l) 10g(l)log(i) FigurFiguree C5:C5: PotentiaPotentiall VVss loglog |iIi|i FigureFigure C6:C6: PotentiaPotentiall VVss lologg |iIii| grapgraphh forfor TestTest IIdd Cu09-01FeOl-Cu09-01Fe01- graphgraph forfor TestTest IdId CuOCuOl 1-- 09H1509H 15,, detaildetailss ofof experimenexperimentt areare 09Fe09-01HI5,09Fe09-01H15, detaildetailss ofof givegivenn iinn TablTablee 2.32.3.. experimentexperiment araree givengiven inin TableTable 2.32.3.. -Mr __ By SIMMER —•-B-+-Byy SIMMERSIMMER • By SIMMER ___ Experimental 0.4 __• ExperimentaExperimentall 0.0.55 • Experimental 0.4 0.0.33 0.0.22 ; ~ w w • X ~-3.-3 .5 '--33 -0.-0.33 -0.4 -0.-0.55 -0.4 ^f- 10g(l)log(l) 10g(l)log(i) FigurFiguree C7:CI: PotentiaPotentiall VVss loglog FigurFiguree C8:C8: PotentiaPotentiall VVss loglog |iIii| Iii|i| graphgraph forfor TesTestt IdId CuOCuOl 1-- grapgraphh foforr TestTest IIdd Cu09-01Fe09-Cu09-01Fe09- 09FeOl-09HI5,09Fe01-09H15, detaildetailss ofof 01H15,, detaildetailss ofof experimenexperimentt areare experimentexperiment areare givegivenn inin givegivenn iinn TablTablee 2.32.3.. 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