Technical note: Flotation as a method for concentration of precious metals in electric arc furnace slag

Automobile exhaust catalysts and electronic equipment, for instance, are rich in platinum group metals (PGMs). At the end of their lifecycles catalytic converters are smelted in electric arc furnaces (EAF) for PGM recovery. With approx. 40ppm, PGM depleted EAF slags still contain significantly higher amounts of PGMs than common primary sources (3–10ppm), in contrast to which the material is oxidic or elementary. Until present, there is no utilisation potential for oxidic EAF slag material. Flotation emerged as a possible option for enriching PGMs from EAF slag. Highest enrichment factor (107±9) was determined for Pt by flotation with sodium O,O′-diethyl dithiophosphate (Na-DEDTP) as collector and polypropylene glycol (PPG) as frother. The Pt content of the concentrate was approx. 1500ppm at a recovery rate up to 17±4%. •Flotation study for PGM recovery from an oxidic EAF slag with 40ppm PGMs•Highest enrichment factor of 107 for Pt by single step flotation•Pt content of the concentrate ~1500ppm at a recovery rate up to 17%