TITLE:
Comparative Study of the Kinetics of Dissolution of Laterite in some Acidic Media
AUTHORS:
Olushola S. AYANDA, Folahan A. ADEKOLA, Alafara A. BABA, Olalekan S. FATOKI, Bhekumusa J. XIMBA
KEYWORDS:
Lateritic soil, Dissolution kinetics, Hydrochloric acid, Nitric acid, Sulphuric acid.
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.10 No.15,
December
20,
2011
ABSTRACT: 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/ro 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.