Recovery of ferronickel by green selective reduction of nickel laterite

Abstract The conversion of nickel laterite into ferronickel is commonly done through a high-temperature pyrometallurgical process that utilizes fossil fuels, which leads to environmental emissions. In order to deal with this, a biomass-based selective reduction process is proposed that uses palm shell charcoal (PSC) as the reductant. In this study, we investigate how to selectively reduce saprolytic nickel ore in various conditions, including pelletization, reduction at 1150°C for one hour, and wet magnetic separation. The optimal conditions, determined with 0.3 stoichiometric carbon, yielded a nickel content and recovery of 22.778 wt.% and 27.541 wt.%, respectively. Phases identified in the reduced pellet include forsterite, diopside, ferronickel, troilite, and olivine. Adjusting stoichiometry influences nickel concentration, resulting in increased recovery; however, excessive stoichiometry intensifies iron metallization, reducing nickel content. The addition of sodium sulfate affects nickel and iron recovery by promoting FeS phase formation, resulting in reduced iron recovery.