Effect of Cl⁻/Mn²⁺ ions on the oxygen evolution and corrosion behaviors of 3D-Pb-Ca-Sn anode for copper electrowinning

In this research, the 3D-Pb-Ca-Sn anode was fabricated and may be a promising anode for copper electrowinning. The effects of Cl⁻ and Mn²⁺ ions on the oxygen evolution and corrosion behaviors of 3D-Pb-Ca-Sn anode were investigated by electrochemical methods. Besides, the phase composition, morphology and element distribution of the oxide layer were also studied. Compared with the traditional Pb–Ca–Sn alloy, 3D-Pb-Ca-Sn anode shows much lower anodic potential, oxygen evolution overpotential and cell voltage, but higher exchange current density. The oxygen evolution overpotential of 3D-Pb-Ca-Sn anode is 0.702 V at a current density of 200 A/cm², which is 75 mV lower than that of Pb–Ca–Sn anode, suggesting potential power savings. These characteristics are mainly attributed to the increase of specific surface area. Although the presence Cl⁻ ions deteriorate the corrosion of the anode, the stability of 3D-Pb-Ca-Sn anodic layer is enhanced by the combined action of Mn²⁺ ions and its excellent 3D structure.