Electrochemical Behaviors of Pb-0.8%Ag Rolled Alloy Anode during and after Zinc Electrowinning - CV Investigations

Abstract

In this paper, electrochemical behaviour of Pb0.8%Ag anode during the 15 days galvanostatic electrolysis in acid zinc sulphate electrolyte solution was investigated with Cyclic Voltammetry (CV) techniques. The phase composition of the anodic oxide layers during the electrolysis was observed using X-Ray Diffraction (XRD). The results revealed that the electrochemical oxidation processes and phase formation varied obviously during the electrolysis for it is a process indicating the formation and stabilization of anodic oxide layer. With the increasing electrolysis time, the anodic peak (PbPbSO4) is mainly present a rise trend and gradually moved in the positive direction while the anodic peak (PbSO4β-PbO2, PbOα-PbO2) strongly moved in the negative direction. The cathodic peak (β-PbO2 and α-PbO2PbSO4) and (PbO and PbSO4Pb) mainly present a rise trend and gradually moved in the negative direction. Besides, the corrosion phase of the anodic oxide layers mainly consist of PbSO4, PbO, α-PbO2 and β-PbO2. With the increasing electrolysis time, the content of α-PbO2 presents a declining trend while the content of β-PbO2 a rising trend. The preferred growth orientation of α-PbO2 and β-PbO2 is (111) and (101) planes respectively.