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:

• (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.