Study on Nickel Extraction from Ultramafic Nickel Sulfide Concentrates with Various Nickel Contents

With the depletion of high-grade nickel sulfide ores and the growing demand for green nickel, it is imperative to study the feasibility of extracting nickel from unconventional resources such as low-grade ultramafic nickel sulfide ores. The ultramafic nickel ores contain pentlandite, pyrrhotite, as well as magnesium silicates. The established smelting technique is limited to processing ultramafic nickel concentrates due to the high MgO levels. The authors proposed a two-stage solid-state thermal upgrading process by metallic iron addition to extract nickel into a ferronickel alloy. The present study investigated the effect of the nickel content of three ultramafic concentrates with %Ni = 7, 7.7, and 8.1, on the effectiveness of nickel extraction. Nickel extraction to ferronickel, nickel grade in the alloy, and the ferronickel particle size were compared.