Separation of Pt(IV) and Pd(II) from the loaded Alamine 336 by stripping

In the solvent extraction of Pt(IV), Pd(II), and Rh(III) from chloride solution, most of Pt and Pd was extracted into Alamine 336 phase, while extraction percentage of Rh was low. In this study, separation of Pt and Pd from the loaded Alamine 336 solution was investigated as a function of the concentration of stripping agents. HClO4, Na2CO3 and a mixture of HCl and thiourea were tested as stripping agents. In our experimental range, a mixture of HCl and thiourea led to the highest stripping percentage of Pd (> 99%) while the stripping percentage of Pt was less than 8%. The low stripping percentage of Pt by the mixture was related to selective stripping of Pd from the loaded Alamine 336. Our results can be utilized in developing a process to separate Pt, Pd, and Rh from chloride solution by solvent extraction.