Experimental Study on the Utilization of Bio-carbon Reductants in the Rotary Kiln-Electric Furnace for Ferronickel Production

Indonesia is committed to reducing its CO₂ emissions by 31.89% unconditionally by 2030, as reflected in its Enhanced Nationally Determined Contribution (NDC) reported in 2022. The mining sector, including nickel mining and smelting, contributes around 10% of global energy-related carbon emissions and must play a role in achieving this target. The RKEF (Rotary Kiln-Electric Furnace) process, which accounts for approximately 80% of global laterite nickel production, primarily for ferronickel or nickel pig iron, relies heavily on coal as a reductant and energy source. This study explores the use of biocarbon as a renewable alternative reductant. Laboratory-scale calcination and smelting experiments were conducted using laterite ore and four reductants: coal, palm shell charcoal, rubber wood charcoal, and mixed wood charcoal. All were characterized for proximate and ultimate composition, ash content, and bulk density. Rubber wood charcoal had the highest fixed carbon (73.2 wt%), while palm shell charcoal showed the highest ash content (9.40 wt.%). Nickel reduction ranged from 4.07 to 24.85%, with the highest reduction achieved using rubber wood charcoal. The results demonstrate that all tested bio-carbons are feasible substitutes for coal in the RKEF process, offering a pathway to decarbonize nickel production in support of Indonesia's NDC goals.