Abstract:T, he influence of mechanical activation on the leaching kinetics of arsenopyrite was studied using a planetary centrifugal mill. It shows that mechanical activat ion can enhance the leaching process of arsenopyrite in a nitric-sulfate acidic solution. The leaching ratio within 20min leaching time can increase from 2% to 80％～100%; 10 and 20 minutes' activation ca n depress the apparent activation energy of leaching reaction from 54.5kJ/mol to 39.0kJ/mol and 34.0kJ/mol, respectively. This means that the leaching reaction becomes little dependent on temperature, and arsenopyrite can change from refractory to flexible one; mechanical activation also increases the interplanar distance between crystal faces. The displacement of atoms from its equilibrium position indicates the increase in inner energy.

Key words: mechanical activation; mechanochemistry; arsenopyrite; leaching; kinetics