Dissolution Kinetics of Thermally Dehydrated Colemanite in Perchloric Acid Solutions

Abstract

In this study, the dissolution of thermally dehydrated colemanite

in aqueous perchloric acid solutions was investigated

in a batch reactor employing the parameters of solid to liquid

ratio, particle size, temperature and acid concentration. It was

found that the dissolution rate increased with increasing

temperature and acid concentration, decreasing particle size

and solid to liquid ratio. No important effect of stirring speed

was observed. The dissolution kinetics of colemanite was

examined according to heterogeneous and homogeneous

reaction models and it was found that the dissolution rate

was controlled by heterogeneous chemical reaction. The

activation energy of the process was determined to be 41.07

kJ mol^-1. The experimental data were tested by graphical and

statistical methods and it was found that the following model

best fit the experimental data

1 - (1-X)^1/3 = 7.56 × 10⁵ (Rp)^-0.1076 × (C_A)^0.4629 × (S/L) -

0.2525 × e^-4938.7/T × t