Author(s)

Olushola S. AYANDA, Folahan A. ADEKOLA, Alafara A. BABA, Olalekan S. FATOKI, Bhekumusa J. XIMBA

Department of Chemistry, Faculty of Applied Sciences, Cape Peninsula University of Technology, P.O. Box 652, Cape Town, South Africa..
Department of Chemistry, University of Ilorin, P.M.B 1515, Ilorin, Nigeria..

Studies on the kinetics of dissolution of a Nigerian lateritic soil in acids media including hydrochloric, nitric and sulphuric acids have been undertaken. The elemental and mineralogical characterization, loss of mass on ignition, moisture content and pH of the material suspension in water were determined. The effects of acid concentration, process temperature, stirring rate and particle size on the dissolution rate were investigated. Experimental results indicated that laterite dissolution was greatly influenced by hydrogen ion concentration and the leaching data fitted a diffusion model. The linear dependence of the rate constant k on 1/r_o ² supported the proposed kinetic model. Values of 60.23 kJmol^-1, 64.31 kJmol^-1 and 67.53 kJmol^-1 were obtained for the activation energies of laterite dissolution in hydrochloric, nitric and sulphuric acids respectively; and the order of reaction was approximately one with respect to each of the three acids.

Lateritic soil, Dissolution kinetics, Hydrochloric acid, Nitric acid, Sulphuric acid.

O. AYANDA, F. ADEKOLA, A. BABA, O. FATOKI and B. XIMBA, "Comparative Study of the Kinetics of Dissolution of Laterite in some Acidic Media," Journal of Minerals and Materials Characterization and Engineering, Vol. 10 No. 15, 2011, pp. 1457-1472. doi: 10.4236/jmmce.2011.1015113.