Kinetics of silver leaching from manganese-silver associated ores in sulfuric acid solution in the presence of hydrogen peroxide

Abstract

Kinetics of silver leaching from a manganese-silver associated ore in sulfuric acid solution in the presence of H2O2 has been investigated in this article. It is found that sulfuric acid and hydrogen peroxide have significant effects on the leaching rate of silver. The reaction orders of H2SO4 and H2O2 were determined as 0.80 and 0.68, respectively. It is found that the effects of temperature on the leaching rate are not marked, the apparent activation energy is attained to be 8.05 kJ/mol within the temperature range of 30 °C to 60 °C in the presence of H2O2. Silver leaching is found to be diffusion-controlled and follows the kinetic model: 1−2x/3−(1−x)2/3=Kt. It is also found that particle size presents a clear effect on silver leaching rate, and the rate constant (k) is proportional to d−20.