Does Interfacial Tension Play the Most Important Role in Slag-Metal Reactions? An Important Aspect in Process Optimization

In view of the nature of heterogeneous reaction of many materials processes, great attention has been paid to the reaction interfaces. Very often, the interfacial tension is given the foremost importance in the study of interfaces in general and slag-metal reactions in particular. As an example, the dependence of entrainment of ladle slag into liquid steel on interfacial tension has been the topic of many researchers.In the present work, the interface between liquid silicon and CaO-SiO₂ slag and the interfacial reaction between silicon and graphite were studied experimentally to gain an insight into the impacts of chemical driving force and interfacial tension on the interfacial phenomena. The results strongly suggested that the chemical driving force could play dominating role in determining the interface, while the interfacial tension would only become important when the slag and metal were reaching equilibrium. Based on the experimental findings, the kinetics of the slag-metal reaction was discussed. Also, the possibility of the entrainment of ladle slag as a source of nonmetallic inclusions was evaluated. The present study would like to draw researchers’ attention regarding the important role of Gibbs energy of the reaction at the interface in the interfacial phenomena and therefore getting an improved understanding of the reaction process.