Electrochemical study of Pb anodes for zinc electrowinning industry

The corrosion resistance and electrochemical behaviour of recovery (recovery anodes are made of remelted alloys) Pb, Pb-0.4Ag (wt-%) and Pb-0.1Ag-0.07Ca (wt-%), anode alloys in acidic zinc sulphate electrolyte were investigated. Their electrocatalytic activity towards oxygen evolution reaction (OER) and corrosion resistance were evaluated using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) methods. The EIS data were approved by Kramers-Kroning transformation (KKT). Also the corrosion resistance of virgin (virgin anodes are made of freshly mined ore which cast from more than 60 ton molten alloy) pure lead anode was compared with recovery pure lead anode by their Tafel diagrams in acidic zinc sulphate electrolyte. Microstructures of the anode alloys were observed using scanning electron microscopy. The results point to that anode Pb-0.4Ag (wt-%) alloy had the lowest corrosion current among the three examined anodes followed by Pb and Pb-0.1Ag-0.07Ca (wt-%), alloys. Also, corrosion resistance the virgin Pb anode is more than recovery one.