TITLE:
Dissolution Kinetics and Leaching of Rutile Ore in Hydrochloric Acid
AUTHORS:
Alafara A. Baba, Folahan A. Adekola, Emmanuela E. Toye, Rafiu B. Bale
KEYWORDS:
Dissolution, Leaching, Hydrochloric Acid
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.8 No.10,
October
20,
2009
ABSTRACT: Experiments on the dissolution kinetics and leaching of rutile ore by hydrochloric acid have been
carried out. The influence of acid concentration, temperature, stirring speed and particle
diameter on the leaching of the ore were examined. The dissolution rates were greatly influenced
by the hydrogen ion concentration, temperature, stirring speed and particle diameter. Kinetic
data analysis showed that the dissolution mechanism followed a diffusion controled shrinking
core model with the surface chemical reaction as the rate controlling step. The study showed that
with 4M HCl solution, about 82.3 % of 10g rutile ore per litre of leachant at 80oC was dissolved
within 120min., using 0.045-0.075mm particle diameter at a stirring speed of 360rpm. The
reaction order with respect to hydrogen ion concentration was found to be 1.0, while
42.28kJ/mol was calculated for the activation energy of the dissolution process. Finally, the Xray
diffraction spectrum showed that the residual solid which amounted to 18% of the initial
solid material contained silica (a-SiO2) and are formed around the shrinking core of the unreacted material.