Abstract
Platinum group metals(PGMs), such as rhodium(Rh) and ruthenium(Ru), are rare and unevenly distributed in the earth's crust. They are used in automobile catalytic converters and electronic equipment. The consumption of such rare resources is unsustainable; therefore, recycling technologies are needed. In this paper, the chemical properties and separation/recovery of Rh and Ru, and PGM smelting/refining technologies are reviewed. In PGM refining processes, Rh and Ru are converted into chloride complexes. To effectively separate each metal, operating conditions of the reaction have to be optimized. The valences of PGM chloro-complexes change with redox potential, and the distributions between chloro- and aquo- complexes vary with chloride ion concentration. The Ru and Os oxides are separated by distillation.
