A Kinetic Study on Leaching of Colemanite in Ammonium Nitrate Solutions

Abstract

The dissolution of colemanite in aqueous ammonium nitrate solutions was investigated in a batch reactor in terms of stirring speed, particle size, reaction temperature, solid-to-liquid ratio and solution concentration. The results showed that the dissolution rate increased with increasing temperature and concentration of ammonium nitrate solution as well as decreasing particle size and solid-to-liquid ratio, while no important effect of stirring speed was observed on dissolution rate. Colemanite could be dissolved up to 100 percent in aqueous ammonium nitrate solutions. The dissolution kinetics of colemanite was examined according to heterogeneous and homogeneous reaction models. The experimental data revealed high activation energy, indicating that the dissolution rate based on heterogeneous reaction models can be expressed as 1-(1-X)(1/3)=3.28x10(4).D-0.653 7.C-1.295 8.(S/L)(-0.490 9).e(-41.40)(RT).t. The activation energy of the process was found to be 41.40 kJ.mol(-1).