Solvent extraction of rhodium, ruthenium, and iridium with HDEHP

Abstract

Solvent extraction of rhodium, ruthenium, and iridium with HDEHP from thioureachloride media was investigated. Under the conditions ([Cl−]=0.50 M, [HDEHP]=1.0M, [SC(NH2)2]=0.50M, pH=4.50, phase contact time 1 min), Rh(III) is extracted 88.3%, Ru(III) and Ir(III) 40.8% and 28.5% respectively at phase ratio 1∶1. The formation of rhodium-thiourea complexes in aqueous solutions, even at 5M chloride concentration, with the possible composition Rh[SC (NH2)2]63+ is confirmed by the observed molar ratio of thiourea to rhodium and UV-spectra.