China Nonferrous Metallurgy

Currently, arsenic is the only impurity known to inhibit copper anode passivation. In copper electrorefining, copper anodes must contain a certain amount of arsenic to obtain high quality cathode copper. Anode passivation is prone to occur in low-arsenic anode electrolysis, which can cause such problems as increased power consumption, worsen cathode copper quality and reduced production capacity. Based on this, the paper analyzes the formation mechanism of low-arsenic anode passivation with respect to the impact the arsenic on the microstructure of copper anode, discusses the impact of copper and acid concentration, temperature and additive in the electrolyte on the electrolytic process and proposes key technology of inhibiting anode passivation. Under the process conditions that the electrolyte temperature is 65℃, copper and acid concentration is lowered to 40g/L and 165g/L respectively, glycerine is added based on the original additive, the current density rises to 280A/m² and there is no anode passivation of low-arsenic anode, which significantly improves the production efficiency of copper electrolysis.