Dissolution Kinetics of Calcined Ulexite in Ammonium Chloride Solutions.

Abstract

In this study, the leaching kinetics of calcined ulexite in ammonium
chloride solutions were investigated. The effect of calcination
temperature, solution concentration, reaction temperature and prehydration
were chosen as parameters. It was observed that the rate
of dissolution increased with increasing calcination temperature,
solution concentration and reaction temperature, while it was not
affected by prehydration. Employing graphical and statistical methods,
the dissolution rate, based on homogeneous reaction model,
can be shown as: (1 - X)^-1 - 1 = k(NH₄Cl)^4/5. The activation energy
for the dissolution of the ulexite sample calcined at 160°C was
found to be 62.65 kJ mol^-1.