A Mechanistic Model to Estimate the Effect of Ladle Slag Entrainment on the Tundish Covering Slag Layer

Ladle slag entrainment during the last stages of ladle draining contaminates the liquid steel in the tundish. Another effect of ladle slag is that it contaminates the tundish covering and hinders it to perform its intended functions. Affected area of tundish covering by ladle slag entrainment was quantified using a first principle-based mechanistic model in this study. Ladle slag hits the bottom of the tundish and bounces back towards the tundish cover and forms a plume-like structure. A reduced scale model was developed, and the phenomena of ladle slag entrainment were monitored using a high-speed high-resolution camera along with shadowgraphy. Slag plume velocity was measured automatically using an image processing software, ImageJ. Plume velocity was found to be reducing during last stages of entrainment. Total affected area consists of a primary area and a secondary extension area. Diameters of the primary, secondary, and total affected area are calculated using a first principle-based mechanistic model and validated with the physical modeling experiments. Additionally, the pushing of tundish slag by the ladle slag was observed in one of the four distinct stages of ladle draining condition.