Application of thermodynamic modeling to slag-metal equilibria in steelmaking

Abstract

The knowledge of the non-metallic phases in equilibrium with liquid steel is very important to the design and control of the results of steelmaking operations, in particular deoxidation, desulfurization and inclusion shape control. Thus, through the control of steel and slag composition it is possible, for instance, to tailor non-metallic inclusions to achieve maximum deformability, to avoid nozzle clogging in continuous casting and to optimize the use of deoxidants. However, the solution of this type of problems requires adequate thermodynamic models and corresponding databases both for the metal phase and for the slag. Close interaction with the steelmaking shop makes it possible a) to evaluate the calculation needs for solving these problems, b) apply the selected models and databases to these questions and c) have a feedback with respect to how adequate the solution is to the actual problem. In this work the current models used for these applications are briefly reviewed, their limitations highlighted and the results of their applications both to laboratory and to plant data are presented and compared.