Mechanism of Oxidative Refining of Platinum Group Metals at the Temperature Gradient

Refining of the platinum-rhodium alloys attracts attention because it opens up the possibility of efficient recycling of raw materials. The remelting process of the platinum-rhodium alloy in the presence of the powder based on Al₂O₃ in an inductive furnace at the temperature gradient in an oxygen atmosphere for eliminating the hard-to-remove copper contaminants was studied. The dependences of the purification rate on the dispersity of the powder based on Al₂O₃, as well as on the Rh content in the initial alloy were established. The interactions of the components involved in the refining process were comprehensively investigated by atomic emission spectroscopy, atomic absorption spectroscopy, X-ray fluorescence analysis, and secondary ion mass spectroscopy.