EXTRACTION KINETICS OF ZINC BY TRILAURYLAMM0NIUM CHLORIDE AT DIFFERENT CHLORIDE CONCENTRATIONS

The rate of the extraction of zinc by trilaurylammonium chloride (TLAHC1) dissolved in toluene was investigated at different aqueous chloride concentrations, using lithium chloride as bulk electrolyte, ranging from 0.5 mol.dm -3 to 2.0 mol dm -3. The experiments were performed using a modified Lewis cell at 25 °C. The rate of metal extraction was found to increase by increasing the aqueous chloride concentration. The data treatment indicated that ZnCl2 and ZnCl4 2- are both kinetically active species. The addition reaction with ZnCl2 is favoured at low chloride concentration while the anion exchange of ZnCl4 2- prevails at high chloride concentration. The addition reaction was explained in terms or interfacial reaction steps. The anion exchange reaction, due to its fast nature, seems to be controlled by diffusion.