Electrochemical Behavior of Pb-Co Anodes in Sulfuric Acid Electrolyte Containing Cl- Ions

Abstract:

Pb-Co anodes with different Co contents (0.5wt%, 1wt%, and 2wt%) were prepared by powder metallurgy, and the traditional Pb-Ca-Sn anode was used as the reference for comparison. The electrochemical behavior of the anodes in the electrolyte containing 160 g/L H₂SO₄ and 500 mg/L Cl^- ions was evaluated by electrochemical measurements. The phase composition, surface morphologies, and element distribution of the anodic oxide layers after galvanostatic polarization for 72 h were investigated. With increasing the Co content, the anodic potential, charge transfer resistance, and oxygen evolution overpotential of the Pb-Co anodes are decreased gradually. After galvanostatic polarization for 72 h, the oxygen evolution overpotential of Pb-2wt% Co anode is lower than that of Pb-Ca-Sn anode by 101 mV. In addition, due to the presence of Cl^- ions, the charge transfer is improved, the oxygen evolution reaction is inhibited, and the oxide layer is deteriorated.

Key words:copper electrowinning;Pb-Co anode;oxygen evolution reaction;corrosion resistance;Cl^- ion