Converting process with slag separation and recycle

A process for converting platinum group metal (PGM) collector alloy, comprising a cycle of the steps of:

• (a) introducing a converter feed into a pot of a converter holding a molten alloy pool, wherein the converter feed comprises:
• (i) 100 parts by weight of a collector alloy comprising no less than 0.5 wt % PGM, no less than 40 wt % iron, no less than 0.5 wt % nickel, no more than 3 wt % sulfur, and no more than 3 wt % copper, based on the total weight of the collector alloy;
• and
• (ii) recycled converter slag in an amount of from about 5 to 100 parts by weight per 100 parts by weight of the collector alloy;
• (b) injecting oxygen-containing gas into the alloy pool to convert iron from the collector alloy to iron oxide and enrich PGM in the alloy pool, wherein the introduction of the converter feed and the injection of the oxygen containing gas are at least partially concurrent;
• (c) allowing a slag comprising the iron oxide to collect in a low-density layer above the alloy pool;
• (d) tapping the low-density layer to recover the slag from the converter;
• (e) separating the slag recovered in step (d) into a first slag portion for recycle to converter feed in step (a) and a second slag portion that is not recycled to step (a);
• and
• (f) tapping the alloy pool to recover the PGM-enriched alloy.