Influence of Fe Ions on Anode Performance and the Mechanism of Action during Copper Electrowinning Process

The performance of the anode varies from the impurity ions in the copper electrowinning process. This work focused on the variation of the electrochemical behavior of the Pb-0.06%Ca-1.2%Sn anode as the Fe ions (Fe³⁺ and/or Fe²⁺) existed in the electrolyte by electrochemical characterization. Copper electrodeposition experiments were conducted under a current density of 300 A/m², with the Fe ion concentration in the electrolyte controlled within the range of 0 to 20 g/L and the Cu ion concentration maintained at 45 g/L at a temperature of 45 °C. The variation in the corrosion resistance, catalytic activity, and structural composition of the anode film layer was analyzed in-depth according to the presence of Fe ions. The results show that the structure of PbO₂ on the surface of the film was changed as Fe ions doped into the anode film, and the oxygen evolution activity of the anode was also improved. However, the corrosion resistance decreased with increasing Fe³⁺ concentration. Furthermore, the addition of 2 g/L Fe²⁺ in the electrolyte containing 2 g/L Fe³⁺ led to an elevation in the corrosion resistance of the anode to some extent and further increased the oxygen evolution activity.