Thermodynamic Modeling of Sn–C and Fe–Sn–C Systems for the Tramp Elements Control in Steel Production

The increasing use of low‐grade ores and ferrous scrap introduces tramp elements such as Sn into iron and steel, which are difficult to remove by conventional methods. This study investigates the behavior of Sn in the Fe–Sn–C system through experiments and thermodynamic modeling using the modified quasichemical model for the liquid phase within the CALculation of PHAse Diagrams framework. The model accurately predicts carbon solubility in liquid, liquid–liquid miscibility, and the activity coefficient of Sn over a wide range of temperatures and carbon concentrations. Key thermodynamic properties including activity coefficient of Sn in liquid, vapor pressures, and partition coefficient of Sn between solid and liquid are derived to identify optimal conditions for Sn removal. Interaction parameters are derived from the developed thermodynamic model for the liquid steel. These findings offer a foundation for industrial application of evaporation‐based refining methods to control tramp elements.