Investigating the Effect of Slag on Decarburization in an AOD Converter Using a Fundamental Model

A high‐temperature thermodynamics model has been coupled with a fundamental mathematical model describing the fluid flow, where boundary conditions were chosen based on data for an industrial AOD converter. Using this model, the effect of both slag phases (a liquid part and a solid part) on the decarburization was studied. More specifically, the separation of chromium oxide to liquid slag as well as the effect of the amount of rigid top slag (solid)on the decarburization was investigated. The liquid slag was considered with respect to the uptake of chromium oxide, while the rigid top slag was only considered with respect to the increase of the metallostatic pressure in the steel melt. The results suggest that separation of chromium oxide to liquid slag results in a decreased decarburization rate. The same conclusion can be drawn with respect to the amount of solid top slag. The figure illustrates our distinction between different types of slags that exist in an AOD. The first stage of injection was simulated for different amounts of a rigid top slag (Figure 3b). Also, the separation of solid chromium oxide in steel to the liquid slag (Figure 3c) was included. It was found that a higher CRE value is theoretically achievable if the amount of top slag can be reduced. Also, the CRE maximum is delayed by the degree of chromium oxide separation to liquid slag.