PROCESS FOR THE PRODUCTION OF A PGM-ENRICHED ALLOY

A process for the production of a PGM-enriched alloy comprising 0 to 60 wt.-% of iron and 20 to 99 wt.-% of one or more PGMs selected from the group consisting of platinum, palladium and rhodium, the process comprising the steps of (1) providing a PGM collector alloy comprising 30 to 95 wt.-% of iron, less than 1 wt.-% of sulfur and 2 to 15 wt.-% of one or more PGMs selected from the group consisting of platinum, palladium and rhodium, (2) providing a copper- and sulfur-free material capable of forming a slag-like composition when molten, wherein the molten slag-like composition comprises 40 to 90 wt.-% of magnesium oxide and/or calcium oxide and 10 to 60 wt.-% of silicon dioxide, (3) melting the PGM collector alloy and the material capable of forming a slag-like composition when molten in a weight ratio of 1:0.2 to 1 within a converter until a multi- or two-phase system of a lower high-density molten mass comprising the molten PGM collector alloy and one or more upper low-density molten masses comprising the molten slag-like composition has formed, (4) contacting an oxidizing gas comprising 0 to 80 vol.-% of inert gas and 20 to 100 vol.-% of oxygen with the lower high-density molten mass obtained in step (3) until it has been converted into a lower high-density molten mass of the PGM-enriched alloy, (5) separating an upper low-density molten slag formed in the course of step (4) from the lower high-density molten mass of the PGM-enriched alloy making use of the difference in density, (6) letting the molten masses separated from one another cool down and solidify, and (7) collecting the solidified PGM-enriched alloy.