Wet chemical pathways for high‐purity nickel sulphate production from nickel pig iron

Abstract A liquid ion exchange‐based process was developed to produce high‐purity NiSO 4 .6H 2 O from nickel pig iron (NPI) using the carboxylic acid extractant Versatic™ Acid 10 (VS10). Iron impurities in the leach liquor were removed via jarosite precipitation, which was further converted into haematite to diversify its application as a value‐added pigment. Nickel was selectively extracted, scrubbed, and stripped under optimized conditions, yielding concentrated NiSO 4 solutions with negligible impurities. The process was validated in a laboratory‐scale mixer–settler unit, achieving a nickel recovery rate exceeding 99% and producing a strip solution containing 113 g/L Ni with combined impurity levels of only 0.061 g/L. Subsequent crystallization yielded NiSO 4 · 6H 2 O of 99.99% purity and 22.3% Ni content, meeting battery‐grade specifications. The overall nickel loss across the entire process was approximately 3.5%. Beyond its technical success, the process embodies circular economy principles by valorizing iron by‐products as pigments and minimizing waste streams, thereby enhancing resource efficiency. Continuous operation confirmed the scalability and industrial viability of the process, establishing a sustainable core technology for high‐purity nickel sulphate production while reinforcing the domestic supply chain for critical materials.