Film-drainage, separation and dissolution of Al₂O₃ inclusions across interfaces between molten steel and ladle-, tundish-and mold-slags

This paper presents calculations on the separation times for solid spherical, octahedral and plate-like micro-inclusions across interfaces between molten low carbon steel and ladle-, tundish-, and mold-slags. The effect of inclusion shape on the interfacial capillary force that arises due to the dynamic interfacial energy change during separation has been investigated and it is shown that this has a significant effect on whether the inclusion separates rapidly or settles at the interface. In the case of settled particles, the inclusion dissolution time was computed based on experimental data. For the slags considered, the most significant physical property was found to be the slag viscosity, which resulted in fast separation for the mold and ladle slag when compared to the more viscous tundish slag.