Extraction and separation studies on Pt(IV), Ir(III) and Rh(III) using sulphur containing extractant

Abstract

The present work reports distribution of platinum(IV), iridium(III) and rhodium(III) from HCl, H2SO4 and HNO3 (0.1–6molL−1) media using Cyanex 471X diluted with toluene. Detailed studies have been conducted to evaluate the effect of different variables influencing the extraction such as equilibration time, temperature, diluent and concentration of extractant. An assessment of the loading capacity, regeneration power and stability of extractant has been made. The extraction behaviour of associated metals namely gold, silver, iron, nickel, cobalt, chromium and copper has been investigated and the conditions for their binary separations involving platinum metals have been optimised. The stoichiometric composition of the extracting platinum and iridium species have been identified. Based on the extraction data separation schemes have been designed to recover platinum, iridium and rhodium from synthetic mixture and real sample.