Effect of Current Densities on the Electrochemical Behavior of a Flat Plate Pb-Ag Anode for Zinc Electrowinning

Abstract

： Westudiedtheanodicpotential,corrosionrate,andanodicpassivelayerofaflatplatePb鄄Ag(0.8% (massfraction, w)anodeoveralongperiodofpolarizationunderdifferentcurrentdensities.Additionally,thecathode currentefficiencyandqualityofthezincproductintheZnSO 4 鄄MnSO 4 鄄H 2 SO 4 electrolytewerealsostudied.The morphologyoftheanodicpassivelayerwascharacterizedbyscanningelectronmicroscopy(SEM).Theresultsshow thatthecurrentdensitygreatlyaffectstheelectrochemicalbehavioroftheanodeandthecathodeduringzinc electrowinningirrespectiveofMn 2+ .Withanincreaseinthecurrentdensity,theanodicpotential,corrosionrate, cathodecurrentefficiency,andquantityofanodeslimeincreasedwhilethePbcontentinthezincproductdecreased. Whenthecurrentdensitydecreasedfrom500to200A • m-2 intheZnSO 4 鄄MnSO 4 鄄H 2 SO 4 electrolyte,thestableanodic potentialandthecorrosionratedecreasedby64mVand40%,respectively.Underalowercurrentdensity,theanodic potentialstabilizesmoreeasilyandthepassivelayerthatformsonthesurfaceoftheanodeisdenseranditadheres bettertothebasebody,whichisadvantageousforthereductionofthecorrosionrate.Therefore,toreducetheanodic potential,corrosionrate,andthequantityofanodeslime,increasethecathodecurrentefficiencyandqualityofzinc product,wesuggestedthattheidealworkingconditionforzincelectrowinningisahighercathodiccurrentdensityand loweranodiccurrentdensity.

The Influence of Anode Composition on Energy Consumption and Current Efficiency in Zinc Electrowinning

“…It can be inferred that the oxygen evolution reaction becomes faster as the Bi content increases in the alloys. 28 Finally, as the chemical and physical properties of Bi is similar to Pb, they will be separated with difficulty. [29][30][31] In the present research, effect of the main parameters on the zinc electrowinning has been studied with Taguchi method (L 25 ), signal-tonoise analysis and analysis of variance (ANOVA) that were infrequent in literature.…”