Solid State Extraction of Nickel from Nickel Sulfide Concentrates

The conventional smelting and refining of Ni sulfide concentrates is an effective strategy for extracting Ni from sulfide ores. However, during the smelting process, sulfur is oxidized to sulfur dioxide (SO2), which poses a significant environmental hazard. The present work investigates the feasibility of an alternative process to recover Ni as a ferronickel (FeNi) alloy while retaining the bulk of the sulfur in a solid phase (FeS), mitigating potential SO2 emissions. A Ni concentrate blended with iron was treated at 950 °C under an Ar atmosphere for 2 h, yielding a FeNi containing ∼22 wt% Ni and a residual iron sulfide containing <2.2 wt% Ni. The composition of these FeNi alloy particles is in good agreement with thermodynamic predictions.