Life-cycle assessment and sustainable supply potential of charcoal for low-emission silicomanganese production in Gabon

Silicomanganese (SiMn) is an important alloy in steelmaking. The production relies on metallurgical coke, causing hard-to-abate emissions. Replacing metallurgical coke with charcoal is a promising mitigation option, but its environmental impacts remain unclear. This study performs a comparative life-cycle assessment of charcoal substitution in SiMn production in Gabon and evaluates domestic biomass potential. The climate impact of conventional SiMn production is 3019 ± 142 kg CO 2 -equivalents per tonne of alloy. Charcoal from rectangular masonry kilns reduces this impact by ∼60% when replacing ∼75% of coke during sintering and smelting. Terrestrial acidification, non-renewable energy use and human health impacts are reduced by 57%, 67% and 10%, respectively. Domestic charcoal demand can be met by establishing biomass plantations on recently abandoned cropland, with potential for surplus production, but areas are highly fragmented. Expansion into adjacent areas with relatively low value for ecosystem carbon storage and biodiversity can increase connectivity and improve logistics.