Leaching of a Nigerian Columbite in Hydrochloric Acid: Dissolution Kinetics

This paper presents the kinetics of dissolution of a Nigerian columbite mineral ore sample in hydrochloric acid media. The effects of acid concentration, process temperature, stirring rate and particle size on the dissolution rate were examined. Experimental results showed that the columbite dissolution increases with increasing acid concentration, temperature, stirring speed and decreases with particle size. With 4.0 M HCl solution, about 15.37% of columbite was dissolved within 120 minutes using < 0.15 mm particle size at a temperature of 80℃ and a stirring speed of 360 rpm. The result of the study indicated that the leaching data fitted a diffusion model. Values of 0.5, 22.40 kJmol-1 and 1.51 X 10-5 min-1 were calculated as reaction order, activation energy and Arrhenius constant, respectively for the dissolution process.