Study the Impact of Various Parameters of slag and metal on Steel Desulphurization by Thermodynamic Simulation

摘要

The desulphurization in secondary treatment of steel depends on many factors like oxygen potential of the slag, chemical composition and physical properties of slag, chemistry of steel etc. There are many expressions to describe slag desulphurization capability, like sulphur partition coefficient, sulphide capacity etc. There are functional dependencies also on slag desulphurization capability with basicity of slag, calcium - aluminate ratio in slag or content of easily reducible oxides (FeO+MnO) in slag. Thermodynamic database software can be applied as a tool for understanding the impact of process parameters on desulphurization by calculating slag metal interaction and characterization of ladle slag. FactSage thermodynamic software, having a wide range of database and calculation module, is able and used in prediction of slag properties such as viscosity, temperature of formation and precipitation of liquid phase, calculation of slag and metal equilibrium, calculation of phase equilibrium diagram etc. FactSage-6.4 was applied to evaluate different thermodynamic properties like, equilibrium solidification, solidus point, liquidus point, viscosity, equilibrium sulphur partition ratio of different slag types in the present work. Co-relation of different parameters like oxygen potential of slag (FeO+MnO content of the slag), Basicity (CaO/Si02 ratio) of the slag, CaO/AI203 ratio and percentage of aluminium in steel, on desulphurization ability of slag were studied using thermodynamic simulations and the comparison was made for different parameters on their impact on the final output.