Dissolution kinetics of calcined colemanite in ammonıum-chloride solution

Abstract

The leaching kinetics of calcined colemanite in ammonium chloride solutions were studied. The effects of calcination temperature, solution concentration, reaction temperature and pre-hydration were evaluated. The rate of dissolution increased with increasing calcination temperature, solution concentration and reaction temperature, while it was not affected by pre-hydration. It was found that the dissolution rate, based on the homogeneous reaction model, can be expressed as: (1-x)-1-1=k[NH4Cl]3/4t. The activation energy for the dissolution of the colemanite sample calcined at 400-degrees-C was found to be 89 kJ mol-1.