Separation and recovery of Cu and As from copper electrolyte through electrowinning and SO2 reduction

Cu and As were separated and recovered from copper electrolyte by multiple stage electrowinning, reduction with SO2 and evaporative crystallization. Experimental results showed that when the current density was 200 A/m2, the electrolyte temperature was 55 °C, the electrolyte circulation rate was about 10 mL/min and the final Cu concentration was higher than 25.88 g/L, the pure copper cathode was recovered. By adjusting the current density to 100 A/m2 and the electrolyte temperature to 65 °C, the removal rate of As was 18.25% when the Cu concentration decreased from 24.69 g/L to 0.42 g/L. After As(V) in Cu-depleted electrolyte was fully reduced to As(III) by SO2, the resultant solution was subjected to evaporative crystallization, then As2O3 was produced, and the recovery rate of As was 59.76%. The cathodic polarization curves demonstrated that both Cu2+ concentration and As(V) affect the limiting current of Cu2+ deposition.