Dynamic Changes in Interfacial Tension between Liquid Fe Alloy and Molten Slag Induced by Chemical Reactions

The authors investigated the change in the interfacial tension with time for various combinations of molten slag and liquid Fe to elucidate the mechanism of the change in interfacial tension between liquid Fe alloy and molten slag over time accompanying reduction/oxidation reactions. The behavior of the change in the interfacial tension over time can be explained by the adsorption of oxygen at the interface and the diffusion of oxygen from the interface into the bulk of the liquid Fe and molten slag. In addition to that, we found that the interfacial tension decreases slowly and greatly from its initial value to a minimum point and then increases slowly to the final equilibrium state when molten silicate slag with low viscosity is brought into contact with liquid Fe without Al content and some of its SiO2 decomposes and dissolves into the liquid Fe. From these results, we suggest that the detachment of oxygen adsorbed at the interface into the liquid Fe is very slow and may be the rate-limiting step.