One-Step Extraction of Nickel from Nickel Sulfide Concentrates by Iron Addition

The conventional nickel smelting and refining is the dominant strategy for nickel production from the sulfide nickel ores. The main disadvantages are the significant amount of SO2 emissions during smelting and complex refining processes. In this paper, the authors investigated a solid-state nickel extraction method that recovered nickel values into ferronickel alloy and simultaneously retained the bulk of sulfur of the nickel sulfide concentrate in the solid iron sulfide, thus mitigating the potential SO2 emissions. The results showed that after heat treatment at 1073 K (800 °C) for 240 min, the residual nickel concentration in the resulting sulfide was only 0.6 mass pct and that in the ferronickel alloy was averaging 16 mass pct. The experimental data were in good agreement with the thermodynamic evaluations. Furthermore, the materials and energy balance were assessed for the thermal treatment process.