Atmospheric leaching of Ni Co Cu and Zn from sulfide t 2024 Minerals Engi

The growing demand for nickel and cobalt increases the interest in extracting metals from secondary sources, such as flotation tailings. A preferential strategy for the processing of the complex and/or low-grade secondary sources may be material integration into existing primary processes. In this research, a robust sulfuric acid leaching treatment was studied for metal extraction from sulfidic flotation tailings (Ni 0.45 %, Co 0.80 %, Cu 0.20 %, Zn 0.58 %). The impact of leaching parameters on metals extraction was studied; oxygen gas (1 – 2 L/ min), ferric ions (0.05 – 0.3 M), and hydrogen peroxide (0.5 – 0.8 M), temperature (30 – 90 ◦ C), sulfuric acid concentration (0.2 – 2 M), and solid – liquid ratio (50 – 100 g/L). It was found that after 30-minutes 20.0 % of nickel, 5.6 % of cobalt, and 33.0 % of the main impurity iron were extracted using oxygen as oxidant. Increasing temperature and sulfuric acid concentration positively impacted extraction, while the further addition of ferric ions and hydrogen peroxide additionally increased extraction levels for nickel and cobalt. The results suggest that the mineralogy of the investigated tailings limited feasible metals extraction up to ≈ 20 % for nickel and ≈ 10 % for cobalt, with efficient zinc extraction and restricted copper extraction.