Sustainable Valorization of Ladle Slag: A Thermodynamic Optimization for Ferrosilicon Production Through an Aluminothermic Reduction

The steel industry generates considerable volumes of ladle furnace slag, typically containing oxides such as SiO₂, Al₂O₃, CaO, and MgO—substances that can pose environmental hazards if not properly managed. Meanwhile, ferrosilicon is widely employed in steelmaking for deoxidation and alloying but requires energy-intensive production methods. In this work, an aluminothermic reduction process is proposed to convert ladle furnace slag into both ferrosilicon and a residual calcium aluminate slag, thereby addressing slag disposal concerns while producing a valuable alloy. Using the thermodynamic software FactStage, key parameters and stoichiometries were optimized to ensure that the final slag composition remains in the calcium aluminate region, suitable for further industrial applications. The resultant ferrosilicon product aligns with standard specifications, offering a potentially more sustainable and cost-effective route to alloy production. A pilot-scale furnace trial will verify these findings, with the ferrosilicon and the leftover slag characterized via spectroscopy to confirm the viability of scaling up. Overall, this research demonstrates an integrated approach that mitigates slag-related hazards and efficiently recovers ferrosilicon, thereby contributing to a more circular and environmentally responsible steel industry.