Solvent Extraction of Rhodium and Ruthenium from Chloride Solutions added Tin(II) with TOA and TOMAC in Benzene

Abstract

The demand for PGMs is increasing year by year due to their excellent physical and chemical properties. Moreover, in order to meet the demand, it is important to develop a highly efficient recovery process of PGMs from secondary resources. Solvent extraction applied to refining process for PGMs offers several advantages over the traditional pre­ cipitation methods and distillation. Solvent extraction efficiency of Rh and Ru from chloride solutions is very low. How­ ever, the extraction efficiency of Rh and Ru can be improved by adding Sn(II) to chloride solutions. In the present study, the extraction of Rh and Ru from hydrochloric acid solutions with tri-n-octylamine (TOA) and tri­octyl methyl ammonium chloride (TOMAC) diluted with benzene were tested to clarify the effect of addition of Sn(II) on the extraction of Rh and Ru and stripping of Rh and Ru. The addition of Sn(II) was effective for the extraction of Rh and Ru and the stripping of Rh and Ru with solutions of sodium nitrite prepared with sodium hydoxide was effective.