Leaching Kinetics of Colemanite in Perchloric Acid Solutions

Abstract

Boron minerals are crucial for our world. Colemanite, which is one of the most widely available boron minerals, has the chemical formula of Ca2·5B6O7·5H2O and a monoclinic crystal structure. The parameters selected for this study are particle size, reaction temperature, acid concentration, solid to liquid ratio and stirring speed. The dissolution rate of colemanite was found to increase with decreasing particle size and solid to liquid ratio, with increasing reaction temperature and acid concentration, while it was not affected by stirring speed. A model equation was constructed for the process. Employing graphical and statiscal methods, the dissolution rate, based on heterogeneous reaction model and evaluation of the experimental data and the mathematical model revealed that the dissolution process was found to be controlled by chemical reaction and the activation energy of this process was estimated to be 46.475 kJ mol–1. The mathematical model to represent the kinetics of this process can be expressed as: 1 – (1 – X)1/3 = 7.73 × 105 × (Rp)–0.2735 × (CA)0.1891 × (S/L)–0.2318 × e–5589.96/T × t.