Determination Of Heavy Materials As Copper,Cadmium,Cobalt And Nickel In Zinc Hydrometallugry

Hydrometallugry produces more than80%of zinc at present days, the technichs process consists of steps as roasting, leaching, purification and electrolytic deposition. No less than20kinds of impurities exist in zinc electrolyte,such as K,Ca,Na,Mg,Al,Pb,Cd,Fe,Mn,Ag,Co,Ni,Cu,Ge,Te, Se, Sb,As,Hg,Ga,etc,which influence current efficiency and the quality of zinc.Some of these impurities are more harmful when coexisting than existing for itself.Therefore,it’s vital to determine and control the concentration of impurities in zinc electrolyte in real time.Methods of impurities determination in coppermetallugry industry include traditional chemical analysis and instrumental analysis.Because of slow preceeding,traditional chemical analysis methods have gradually gone out of use. Optical methods and electrochemical methods are mainly used in instrumental analysis. Commonly used instrumental analytical methods contain polarography, voltammetry, atomic abosorption spectrophotometry,atomic emissions pectrophotometry,etc.Electrochemi cal analysis advantages in straightforward procedure,low cost,etc. This article mainly concern the methods of spectrophotometry and electrochemical methods,combining flow injection analysis and K-matrix method in determination of impurities in Zinc electrolyte.The K-matrix method makes it possible to calculate the overlapping absorption curves of Cu,Cd and Ni.By this photometric determination method,we get the concentration of Cu,Cd,Ni are5.78×10-7mol/L、4.30×10-7mol/L5.30×10-7mol/L.This article also deals with method of dissolving sediment in zinc electrolyte transfer line.The self-made disincrustant can dissolve the sediment short time at room temperature.The differential pulse anodic stripping voltammetric (DPASV) method described in this work achieves the required resolution for the determination of cadmium,copper and colbat in zinc plant electrolyte in the solution consisting of HAc-NaAc(as buffer solution),NH4Cl and vitamin C.The potential of peak reduction current for Cd2+, Cu2+, Co2+are-0.82V,-0.22V,+0.02V(vs.SCE), the linear ranges are6×10-7～2.5×10-5 mol/L,3×10-7～3×10-5mol/L,1.5×10-6～3.0×10-4mol/L.The method is applied to the determination of actual samples, with the relative standard deviation less than5%and recovery of95.94～101.90%.and the results are consistent with the ICP-AES method.