Identification of the significant factors determining extractability of Ni and Cu after sulfation roasting of a PGM-bearing chromitite ore

It was possible to decompose the chromatic-ferritic structure and produce water-soluble metal species by roasting the ore containing 12.80 g/t Pt, 15.20 g/t Pd, 0.0646% Cu, 0.31% Ni, 13.60% Fe and 10.40% Cr. Approximately 90% Ni and 77% Cu were recovered after roasting at 550 °C in closed atmosphere for 2 h with 462 kg/t H2SO4, 76.9 kg/t Na2SO4 and by leaching at 80 °C with 2 wt% solid density for 24 h. The raw ore, roasted mass and water-leach residue were characterized by fire assay and Tescan Integrated Mineral Analysis (TIMA GM Model). Pt + Pd grade has been upgraded from 28 (raw ore) to 32.38 g/t (water-leach residue).