Solvent extraction of tin(IV) with PC-88A from sulfuric acid solutions containing chloride ions

Solvent extraction of tin(IV) with PC-88A in EXXSOL D-80 diluent from sulfu ric acid solutions containing chloride ions was investigated to elucidate t he effect of the concentration of the reactant species and the stoichiometr ic relation of the extraction reaction. Because of a difference in extracti on mechanism from the usual cation exchange mechanism for metals with acidi c extractants, tin(IV) was more strongly extracted from high concentrations of sulfuric acid and the extraction increased with increasing sulfuric aci d concentration. By plotting the distribution ratio against activity of sul furic acid, it was found to have a 3(rd) order dependence on the activity. The distribution ratio was found to have a first order dependency on the co ncentration of the dimeric reagent. The extraction increased with increasin g concentration of chloride at low chloride concentrations while it decreas ed at high chloride concentrations. From these experimental results, it was inferred that tin(IV) is extracted as the complex, SnCl(HSO4)SO4 . 2HR.