Sulfur Removal and Iron Recovery from High-Pressure Acid Leaching Residue of Nickel Laterite Ore

High-pressure acid leach (HPAL) residue from laterite nickel ore is a potentially valuable resource for ironmaking; however, its efficient utilization is hindered by its high sulfur content. In this study, an effective and straightforward method is proposed for sulfur removal from HPAL residue. The process involves sieving and sodium carbonate leaching, enabling significant sulfur reduction from 5.12 to 0.81% and simultaneous enrichment of iron content from 47.12 to 55.27%. The sulfur content in the treated HPAL residue falls below the permissible level for the ironmaking industry, rendering it suitable for use as a low-grade iron ore. This innovative approach not only facilitates the valuable utilization of HPAL residues but also mitigates solid waste emissions, addressing the economic and environmental challenges associated with large stockpiles of solid waste.