Lead-Based Anodes for Copper Electrowinning: Effect of Grain Size on Mechanical and Anticorrosion Properties

Abstract

The aim of this paper was to study the effect of the grain size of lead-based anodes for copper electrowinning on their mechanical and anticorrosion properties. Aged anodes were cold rolled to different thicknesses, achieving reductions varying from their standard 50% up to 75%. The grain size, yield stress, and corrosion behavior of the different rolled samples was evaluated by galvanostatic polarization essays. It was found that by lowering the grain size, the yield stress of the anodes increased up to 66 MPa and the improved anodes maintained a higher yield stress with time and throughout temperature operation in cells, as compared with the currently used anodes. Also, a significant diminution of the corroded mass, up to 30%, was observed as cold reduction increased due to the formation of a more compact and less permeable PbSO₄ at lower grain size.