Effect of pretreatment on the anodic behaviour of lead alloys for use in electrowinning operations. I

Lead alloys are widely used as anodes in electrowinning operations, for the recovery of metals such as zinc, copper and chromium. When lead alloys are used as such it takes a long time for the build up of a compact, adherent and protective lead dioxide film. During the initial period prior to the build up of the compact layer of lead dioxide, the rate of anodic dissolution is very high, leading to a decrease in the purity of the cathode deposit. In order to minimize the duration of the conditioning of the anode, it is customary to build up a compact lead dioxide layer by pretreating the anodes in suitable electrolytes. An attempt is made to evaluate the performance of the pretreated electrodes by potentiodynamic methods.