Polarization behavior of lead-silver anodes in zinc electrowinning electrolytes

Lead anodes performance is important in zinc electrowinning (EW) as it greatly influences the final product quality and operating costs. Pb-based alloys are used in EW because they are cheap, conductive, and relatively stable at high potentials and low pH. In this study, polarization behavior and the oxygen evolution reaction (OER) on a Pb-Ag alloy were examined as a function of H ₂SO ₄, Mn ²⁺, Cl ^-, Zn ²⁺ concentrations and solution temperature. The slope of the oxygen evolution region and the OER potential were determined using potentiodynamic experiments. Corrosion products were studied using potentiostatic experiments along with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffractometry (XRD). The relationship between surface morphology of the electrode and operating potential was studied.