Catalytic Oxidation and Kinetics of Oxidation of Coal-derived Pyrite by Electrolysis

The catalytic oxidation of coal-derived pyrite into SO 2-_4 and Fe 3+ and kinetics of oxidation of coal-derived pyrite by electrolysis was studied in a batch reactor. In this paper, the influence of electrolysis conditions, including particle size, electrolysis potential, time, temperature, the acidity of electrolysis solutions, the concentration of additive, the concentration of pyrite, on the rate of conversion of pyrite (C_r), are described. It is obvious that the rate of conversion of pyrite (C_r) increases with the raise of potential, time, temperature, acidity and the concentration of catalyst (MnSO_4), but decreases with the raise of concentration of pyrite. These experimental data were analyzed on the basis of unreacted shrinking core model. The reaction-controlling step was found to be the chemical reaction between Mn 3+ and pyrite. The apparent activation energy for oxidation of coal-derived pyrite into SO 2-_4 and Fe 3+ by electrolysis is 29.6 kJ/mol.