KINETICS OF CHROMIUM AND MANGANESE DISSOLUTION FROM A TITANIUM MINERAL

The kinetics and mechanism of leaching of chromium and manganese values from powdered ilmenite ore was studied in HCI solutions at 40-70(degree)C. The effect of different physico-chemical parameters on the leaching rates of Cr and Mn values are also investigated. The leaching rates of both Cr and Mn values increased with increasing temperature and HCI concentration, but decreased with increasing particle size of the ore, and was independent of stirring speed. Analysis of the data with shrinking core model and the relatively high apparent activation energies (>70 kJ.mol^-1) indicate that the leaching rate was controlled by a chemical reaction at the mineral surface.