Hydrometallurgical recovery of platinum group metals from spent automotive converters

This work presents studies on the recovery of platinum group metals (PGM), especially platinum and rhodium, from spent automotive converters using hydrometallurgical techniques such as leaching and liquid-liquid extraction. The XRD analysis confirmed the presence of indialite – the high temperature hexagonal form of cordierite (the main catalyst building material) in the solid samples. The influence of time and temperature on the leaching of PGM from spent automotive converters was investigated. The largest amounts of Pt(IV) and Rh(III) were leached with freshly prepared aqua regia and a mixture of HCl, $H_2SO_4$ , and $H2O_2$. Further, liquid-liquid extraction with quaternary phosphonium ionic liquid (Cyphos IL 101) was applied to recover PGM from the leach solutions (after leaching with a mixture of HCl, $H_2SO_4$, and $H_2O_2$ and to separate Pt(IV) from Rh(III).