The Separation of Rhodium and Iridium. III. Secondary Reactions Relating to Chlorination

Abstract

The macroscale separation of rhodium and iridium is a very complex system. This is based on the selective removal of [IrCl₆]²⁻ from the aqueous hydrochloric acid feed solution. There are number of factors involved in the separation process that need to be investigated from a fundamental point of view before their effects on the total system can be assessed. In this article an effort is made to understand the underlying chemistry involved in the separation of Ir(IV) from rhodium. The significance of secondary reactions relating to chlorination is studied and evaluated.

Keywords:

• Rhodium
• Chloridation
• Secondary effects
• IRA‐900

Acknowledgments

The authors wish to thank UPE, Impala Platinum, THRIP, and the FRD for financial support.

Notes

^aThe term chlorine in this context refers to all the different species originating from Cl₂ and present in aqueous solutions. It will be referred to as [Cl₂]_total.