Effect of mechanical activation on the leaching kinetics of pyrrhotite

BET, SEM, and particle size analysis was used for studying the changes in surface and bulk properties of mechanically activated pyrrhotite in a vibrating mill. The results showed that mechanical activation increased microstructure defects and specific surface area of pyrrhotite, and decreased powder particle size. And the formation of aggregates was very obvious. The influence of mechanical activation on leaching kinetics of pyrrhotite by FeCl3–HCl solutions was investigated. When pyrrhotite was mechanically activated for 10 min, 20 min and 40 min, the apparent activation energy decreased from 133 kJ/mol to 33, 26 and 25 kJ/mol, respectively. Compared with the non-mechanical activation method, mechanical activation greatly improved the activity of pyrrhotite and decreased the apparent activation energy, so that the reaction speed was accelerated remarkably.