Separation of platinum and palladium from chloride solution by solvent extraction using Alamine 300

Abstract

The separation of platinum and palladium from chloride solution by solvent extraction, using Alamine 300 as an extractant, has been studied. The effect of different parameters such as the concentration of HCl in the feed solution, NaCl concentration, extractant concentration, and platinum and palladium concentrations in the feed solution has been evaluated. Stripping behavior was also studied using different stripping agents, such as sodium thiocyanate and thiourea. Using a saturated solution of sodium chloride at a pH 1.5, platinum was selectively extracted as the major component, along with minor amounts of palladium. By adding a saturated solution of NaCl to the aqueous phase, palladium extraction could be decreased. Additionally, with the use of 0.5 M HCl in place of NaCl, both metals were studied. Selective stripping of platinum accomplished using sodium thiocyanate, and the selective removal palladium was achieved with sodium thiosulfate. This process can achieve a 99.9% purity of platinum even in very dilute solution.