METALLURGICAL PROCESS FOR MANUFACTURING ELECTROWINNING LEAD AND LEAD ALLOY ELECTRODES

Lead and lead-alloy anodes for electrowinning metals such as zinc, copper, lead, tin, nickel and manganese from sulfuric acid solutions, whereby the electrodes are processed by a repetitive sequence of cold deformation and recrystallization heat treatment, within specified limits of deformation, temperature and annealing time, to achieve an improved microstructure consisting of a high frequency of special low Σ CSL grain boundaries (i.e. ⊃50 %). The resultant electrodes possess significantly improved resistance to intergranular corrosion, and yield (1) extended service life, (2) the potential for reduction in electrode thickness with a commensurate increase in the number of electrodes per electrowinning cell, and (3) the opportunity to extract higher purity metal product.