Preparation of High Nickel Grade Ferronickel From Nickel Sulfide Concentrate with Minimal Sulfur Dioxide Emission

Nickel is a key element for stainless steel and lithium-ion batteries. However, the conventional extraction of nickel from sulfide ores generates large amounts of sulfur dioxide and slag and demands complex-refining processes to produce marketable products. The authors have proposed a sustainable nickel extraction strategy that retained the bulk of sulfur as solid iron sulfide and extracted nickel value into ferronickel simultaneously. This simple thermal treatment comprised two stages and yielded high nickel grade, high nickel extraction, and large ferronickel grains. The present study demonstrates that these grains of ferronickel can be efficiently separated from the nickel-depleted iron sulfide matrix. The high nickel grade (30 mass pct) and relatively low remaining sulfur concentration (4 mass pct) of the recovered ferronickel concentrate make it a potential feedstock for either stainless steel or nickel-containing cathode material.