Pyrometallurgical processing of a low copper content concentrate based on a thermodynamic assessment.

Highlights • An alternative method for CuSO 4 has been proposed using a low copper content concentrate. • A thermodynamics assessments was made in order to support the process. • The SO 2 (g) enrichment has significant effects on reaction system. • The proposed methodology allowed the complete separation of Cu from Fe. • It was observed that the roasting must be conducted above 600 °C in order to separate Cu and Fe. Abstract Concentrates containing sulphide minerals are an important raw material source in the extractive metallurgy of nonferrous metals. This study aims to evaluate the pyrometallurgical processing of a sulphide concentrate with a relatively low copper content through an alternative methodology (roasting-leaching route), in order to selectively obtain CuSO 4 and Fe 2 O 3 for the chemical industry. The thermodynamic behaviour of the concentrate was evaluated in order to identify the conditions to fulfil the aforementioned selectivity. The presence of SO 2 (g) in the reaction system could be responsible for increasing CuSO 4 stability without compromising FeSO 4 dissociation. Subsequently, experiments were carried out to evaluate the temperature and chemical composition of the atmosphere. Both obtained products and raw materials were characterized using common techniques (e.g. X-Ray Diffraction and SEM/EDS). Finally, some roasting products were submitted to water solubilisation tests in order to verify, in practice, the selective conversion of copper and iron sulphides into CuSO 4 and Fe 2 O 3. The proposed methodology allowed for complete separation of Cu from Fe, roasting experiments conducted at 873 K (600 °C) and 923 K (650 °C). This was observed in praxis through the formation of a blue liquor, typically copper sulphate, and a brown solid residue which was deprived of Cu, as verified by the applied characterization methods. [ABSTRACT FROM AUTHOR]