A multi-scale ICME framework for designing functional aluminosilicate melts in staged deoxidation processes

• Slag-steel interface controls deoxidation through reaction-mass transport synergy. • Cleaner deoxidation cuts Al use by over 60% and reduces process carbon footprint. • Clarified factors influencing the adsorption of hazardous oxides in slag interface. • Multiscale material design links atomic simulation to industrial practice. A rational material design strategy for molten slags is presented to achieve synergistic control over oxide inclusions and process economics in steelmaking. Targeting the CaO–Al 2 O 3 –SiO 2 –6%MgO system, a stage-specific precise deoxidation route is proposed that decouples carbon pre-deoxidation from aluminum final deoxidation. Employing an ICME framework integrating thermodynamic equilibrium analysis and molecular dynamics simulations, processing-structure–property relationships are established. By tailoring slag basicity and the carbon-to-aluminum deoxidation ratio, atomic-scale structural evolution and its decisive influence on transport properties and thermodynamic behavior are revealed. This computationally guided design was validated in an industrial trial. The implemented medium–low basicity slag system within the staged deoxidation process simultaneously enhanced steel cleanliness and cost effectiveness, reducing inclusion density by 1.5 /mm 2 and aluminum consumption by over 60%. This work demonstrates a proactive multiscale design paradigm for functional metallurgical materials, integrating atomic-scale insight, predictive simulation, and industrial validation to address dual challenge of performance and cost.