<p>Ladle furnace slag (LFS) is a solid waste by-product generated during the secondary steelmaking process and is utilized in applications like cement production, cementitious materials, concrete aggregates and CO₂ sequestration. However, its utilization is often limited due to several challenges, such as delayed setting times, low hydration activity, and the risk of disintegration into powder during cooling caused by volume expansion. These issues are further compounded by its complex mineral structure and variable chemical composition. The present study proposes a novel and sustainable method for the utilization of aluminium-killed LFS which typically contains 30 wt% Al₂O₃. The process involves alkaline leaching using sodium carbonate (Na₂CO₃) under optimized conditions as liquid-to-solid ratio of 5 at 70&#xa0;°C allowing alumina recovery rates exceeding 85%. CO₂ purging promotes the precipitation of aluminium hydroxide while sodium carbonate is regenerated with 96% efficiency and reused in successive leaching cycles. This approach offers an effective solution for recovering alumina from aluminium-killed LFS, transforming industrial waste into a valuable resource. It supports de-carbonization efforts, requires minimal capital investment, and aligns with sustainability goals by lowering environmental impact. The resulting residue, composed of precipitated calcium carbonate (CaCO₃), can be calcined and used either as a partial flux replacement in steelmaking or as an alternative raw material in Portland cement production.</p> Graphical Abstract <p></p>