Abstract: Leaching process of Mn from low grade pyrolusite with SO2 in liquid phase was studied. Effects of agitation speed

leaching temperature

SO2 concentration and pH on Mn extraction rate were determined. Changes of particle size and surface element content of pyrolusite were determined. The results indicate that effect of outward diffusion can be eliminated when agitation speed at 400r/min. Mn extraction rate increases with increasing temperature

SO2 concentration and decreasing pH. A decrease of pyrolusite particle size at 20%

a decrease of Mn at 73% and a increase of Si at 18% on pyrolusite surface were found when Mn extraction rate at 80%. The leaching kinetics showed that the leaching reaction is controlled by both chemical reaction on particle surface and diffusion across the product layer. The determined activation energy was found to be 36.85 kJ/ mol and the reaction orders with respect to SO2 concentration and H+ were 1.5995 and 0.5884

respectively.