Numerical simulation of slag-foaming dynamics in CaO–SiO₂–Al₂O₃–FeO steelmaking slags

Slag foaming is an important operation in electric arc furnace steelmaking, and modern steel shops worldwide currently apply this practice. However, an efficient slag-foaming practice requires not only control of the process variables at the industrial scale but also a fundamental understanding of the foaming phenomena, which can be achieved through the development of mathematical models. However, research in this field is lacking owing to the extreme complexity of slag foaming. In this study a 3D computational fluid dynamics model was developed using the Euler–Euler multiphase flow model coupled with a population balance model. The model predicted the foam height and foaming index. It was validated for batch smelting slags containing CaO–SiO₂–Al₂O₃–FeO slags at 1773 K and constant slag basicity, with an error of less than 1.4%. When applied to steelmaking slags, the model accurately reproduced slag foaming. The model predictions indicated that increasing the FeO content from 3wt% to 30wt% decreased the foaming index from approximately 1.3 to 0.5.