LIQUID-LIQUID EXTRACTION AND SEPARATION OF RHODIUM(III) FROM OTHER PLATINUM GROUP METALS WITH CYANEX 925

Abstract

Liquid-liquid extraction of platinum group metals Rh(III), Pt(IV), and Pd(II) was carried out from aqueous chloride media with Cyanex 925 in the absence and presence of tin (II) chloride. In the absence of tin (II) chloride, the order of extraction was found to be Pd > Pt > Rh. However, in the presence of tin (II) chloride, it changed to Pt > Rh and is negligible in the case of palladium. The extraction of rhodium was studied under the influence of variables such as hydrochloric acid, reagent, and tin (II) chloride concentrations; equilibration time; and effect of diverse ions. The separation of Rhodium (III) from Pt(IV) and Pd(II) was enabled because of differences in their extraction and stripping abilities when Cyanex 925 is used.

Keywords:

• Extraction
• Rh(III)
• Cyanex 925
• Stripping
• Separation

ACKNOWLEDGMENT

The authors are thankful to Cytec Canada Inc, Canada, for supplying the Cyanex 925 gift sample.