Dissolution kinetics of galena in acetic acid solutions with hydrogen peroxide

The kinetics of leaching lead from galena in acetic (ethanoic) acid solutions with hydrogen peroxide are investigated with regard to stirring speed, temperature and concentration of HAc and H2O2 concentration. Oxidation of galena with H2O2 to produce lead sulphate which dissolves by complexing Pb2+ with acetate anion (PbCH3COO+ and Pb(CH3COO)2). Results indicate that the rate of galena dissolution is controlled by a surface chemical reaction with an apparent activation energy is 65.6 kJ mol− 1 in the temperature range 30–70 °C. Both HAc and H2O2 affect the rate of extraction of lead as an acetate complex. The order of reaction was 0.79 and 0.31 for H2O2 and HAc concentrations, respectively.