Processing of chalcopyrite concentrate by sulfating roasting

Chalcopyrite (CuFeS₂) is one of the primary minerals processed on an industrial scale for copper production and often dominates copper concentrates sent for pyrometallurgical processing. This study demonstrates the efficient and selective extraction of copper from chalcopyrite concentrate through sulfating roasting, sulfuric acid leaching, and solvent extraction. At a roasting temperature of 700 °C for 1.5 h, chalcopyrite fully decomposes into hematite (Fe₂O₃) and chalcanthite (CuSO₄). Leaching the calcine with a 0.02 M sulfuric acid solution transfers most of the copper to the aqueous phase, while iron concentrates in the solid residue. Additionally, precious metals concentrate in the residue after leaching of the calcine, with the following content in g/t: Pd – 41.61, Pt – 5.65, Ag – 96.22, Au – 4.81. The removal of iron from the leach solution using solvent extraction with di-2-ethylhexyl phosphoric acid was highly effective: with a 25 % extractant solution and an organicto-aqueous ratio of 1:1 over two stages, the iron concentration in the aqueous phase dropped from 3.05 to 0.01 g/dm³, and with an organic-toaqueous ratio of 1:2 over four stages, it decreased to 0.006 g/dm3. After iron purification and solution evaporation, copper sulfate was obtained with the following composition (%): CuSO₄·5H₂O – 99.84 (equivalent to 25.42 % copper), Ni – 0.014, Al – 0.007, Fe – 0.0003, As – 0.0002.