Leaching and Kinetic Modelling of Molybdenite Concentrate Using Hydrogen Peroxide in Sulfuric Acid Solution

Leaching of molybdenite concentrate with hydrogen peroxide in sulfuric acid solution was investigated to determine the effects of reaction time, reaction temperature, H2O2 concentration, H2SO4 concentration, pulp density and rotation speed on molybdenum extraction and molybdenite dissolution kinetics, using the Taguchi method. From analysis of variance (ANOVA) for molybdenum extraction, the most significant factors were H2O2 concentration, pulp density and reaction temperature. The optimal factor levels to maximize extraction were determined. As the leaching process does not result in an ash layer, only chemically controlled kinetic model was applied. ANOVA for the reaction rate constant showed that H2O2 concentration made the greatest contribution to the model, and reaction time and temperature were also statistically significant factors. The reaction rate constant increased with increasing temperature and H2O2 concentration. The order of reaction with respect to H2O2 and activation energy for the dissolution were determined to be 1.21 and 46.5 kJ/mol, respectively, and a semi-empirical rate equation was derived.