Effect of added cobalt ion on copper electrowinning from sulfate bath using doped polyaniline and Pb-Ag anodes

Abstract

Effect of added Co 2+(aq) on copper electrowinning was studied using doped polyaniline (Pani) and Pb-Ag(1%) anodes and a stainless steel cathode. The presence of added Co 2+(aq) in the electrolyte solution was found to decrease the anode potentials. The optimum level of Co 2+(aq) concentration in the electrolyte, with respect to the maximum saving of power consumption was established. Linear sweep voltammetry (LSV) was used to study the influence of added Co 2+(aq) on the anodic processes in a copper sulfate-sulfuric acid electrolyte. The oxygen-evolution potential for Pani anode is depolarised at lower current densities (⩽0.01 A/cm 2) and attains saturation at ρ(Co 2+) o≈0.789 g/L; whilst the oxygen-evolution potential for Pb-Ag(1%) anode is depolarised at higher current densities (⩽0.02 A/cm 2) and attains saturation at ρ(Co 2+) o≈1.315 g/L. The preferred orientations of the copper deposits change from (220) to (111) with the addition of 0.394–0.789 g/L Co 2+ but higher concentrations favor (220) orientation again.