Studies on the Selective Separation of Ir(IV), Ru(III) and Rh(III) from Chloride Solutions using Alamine 336 in Kerosene

Abstract

The liquid–liquid extraction of Ir(IV), Ru(III), and Rh(III) from chloride solution was studied under different conditions of aqueous‐ and organic‐phase component concentrations using Alamine 336 (A336) as an extractant. The differences obtained in the extraction of individual metals at different concentrations of A336 and HCl in the organic and aqueous phases respectively were used to mutually separate the three metals. A two‐step separation scheme was proposed. In the first step, Ir(IV) was selectively extracted using a solvent comprised of 0.1% A336 and 10% TBP in kerosene. In the second step, Ru(III) was quantitatively extracted using a solvent comprised of 5% A336 and 10% TBP in kerosene (all % v/v). Rh(III) was selectively left behind in the raffinate. Under controlled experimental conditions, we were able to eliminate the base metal ions commonly associated with Ir, Ru, and Rh during the extraction and the stripping process.