Effects of Co2+ in diaphragm electrolysis on the electrochemical and corrosion behaviors of Pb[sbnd]Ag and Pb anodes for zinc electrowinning

Abstract

In this study, the influence of Co2+ (2 g/L) on the electrochemical behavior of cast Pb−Ag (0.6 wt%) anode and cast Pb anode was investigated in diaphragm electrolysis by galvanostatic polarization, cyclic voltammetry, and anodic polarization and with Tafel curves. In addition, analyses of the anodic weight loss, metal ion concentration, phase analysis, and scanning electron microscopy images of the oxide layer and substrate were also conducted. The results show that the diaphragm electrolysis cell completely prevented the metal ions in the anode chamber from penetrating into the cathode chamber. The Co2+ in the solution was gradually oxidized to Co3+ during the oxygen evolution reaction (OER), which facilitated the reduction of the potential of the OER, decreased the time for the potential of the Pb−Ag (0.6 wt%) anode and Pb anode to stabilize, and improved the corrosion resistance of the Pb−Ag (0.6 wt%) anode and Pb anode by weakening the oxidation of the anodic metal substrate during the OER.