Leaching Kinetics of Stibnite in Sodium Hydroxide Solution

The leaching kinetics of stibnite in basic solution has been investigated. spherical pellets of antimony sulphide were dissolved in 1 molar sodium hydroxide solutions at different temperatures. it was found that the shrinking core with ash layer model could satisfactorily explain the dissolution process. using this model, it was found that initially the rate controlling step was a chemical reaction with activation energy of 10.2 kj/mol. as the ash layer built up, diffusion through the ash layer became the rate controlling step. the activation energy for this step was found to be 33.4 kj/mol. it was also observed that smaller particle size, larger solid to liquid ratio, and higher naoh solution concentrations resulted in higher concentrations of stibnite in the leach solution.