Effect of impurities in recycling water on Pb-Ag anode passivation in zinc electrowinning process

Effect of impurities in recycling water on Pb-Ag anode passivation in zinc electrowinning process was investigated by linear scan voltammetry. Results show that passivation process would be affected in the presence of Cl− and F− in recycling water. It was highly advantageous to take H2SO4 concentration as 180 g/L, Mn2+ concentration as 3-5 g/L and F− less than 42 mg/L. However, passivation process would not be affected when Cl− concentration was less than 13 mg/L without any other ions, or when mass ratio of Mn2+ to Cl− existing in electrolyte was 8, where Cl− concentration could reach up to 625 mg/L.