Anodic Behavior of Pb-Ag-Ca-Sr Alloy in Zinc Electrowinning

Abstract

Over potentials for oxygen evolution reaction, corrosion rate, surface product after polarization and microstructure before and after polarization of Pb-0.2%Ag-0.08%Ca-0.05%Sr quaternary anode in zinc electrowinning were studied and compared with Pb-0.6%Ag binary anode. The results show that over potentials for oxygen evolution reaction on Pb-0.6%Ag and Pb-0.2%Ag-0.08%Ca-0.05%Sr anodes are 675 mV and 790 mV, respectively, while the corrosion current density are 8.2μAcm-2 and 20.1μAcm-2. The surface structure after experiment of in Pb-Ag anodes is dense and tightly attached to the base, while the surface of Pb-Ag-Ca-Sr is loose and porous. The phases of the surface are PbO2, PbSO4 and MnO2 on both anods.