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 H(2)O(2) concentration. Oxidation of galena with H(2)O(2) to produce lead sulphate which dissolves by complexing Ph(2+) with acetate anion (PbCH(3)COO(+) and Pb(CH(3)COO)(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)I in the temperature range 30-70 degrees C. Both HAc and H(2)O(2) affect the rate of extraction of lead as an acetate complex. The order of reaction was 0.79 and 0.31 for H(2)O(2) and HAc concentrations, respectively. (C) 2007 Elsevier B.V. All rights reserved.