Potentiostatic studies of the influence of temperature on lead-silver anodes during electrowinning and decay period

The electrochemical behaviour of the Pb-0.7% Ag anode has been investigated in zinc sulphuric acid electrolyte containing 5, 8, 12g/L Mn2+ by electrochemical measurements at different temperatures of 35 degrees C, 40 degrees C, 45 degrees C. It was observed by cyclic voltammetry before electrolysis that temperature increase from 35 degrees C to 45 degrees C resulted in a decrease in the oxidation peak I (Pb PbSO4) and an increase in the oxygen evolution peak II (2H(2)O O-2+4H(+)+4e). At 2.01V/SHE, the current densities of Pb-0.7% Ag anode in sulphuric acid solution containing 8g/L Mn2+ at 35 degrees C, 40 degrees C and 45 degrees C increased from 26.5 at 35 degrees C to 28.5 and 37.7mA/cm(2) at 40 and 45 degrees C, respectively. In the presence of ZnSO4 addition to the sulphuric acid solution, the anodic current of oxygen evolution at 2.01V/SHE decreased by approximate to 18% at 40 degrees C. After 2h of potentiostatic polarisation in the presence of zinc sulphate addition at 2.01V/SHE, electrochemical Noise Measurements showed that the admittance (corrosion rate) of the Pb-0.7% Ag anode in the zinc electrolyte increased with the increase in temperatures during decay. This tendency was also confirmed by linear polarisation and impedance measurements.