Kinetic Study On Compositional Variations Of Steel,Slag And Inclusions In A Multiphase System Of "Steel-Slag-Inclusion-Refractory-Alloy-Air"

A steel-slag-inclusion-refractory-alloy-air multiphase model was developed to calculate the compositional changes of steel,slag and inclusions during the refining process.Reactions between the molten steel and the slag,reactions between the molten steel and inclusions,reactions between the refractory and the molten steel,reactions between the refractory and the slag,the alloy dissolution,the removal of inclusions by floating are all considered in the multiphase model.The influence of different sizes of inclusions on the compositional changes of steel,slag and inclusions were considered in the present study.The mass transfer coefficients are influenced by the average speed of the molten steel,the speed of the molten steel near the side wall and the plume fraction,which are obtained by mathematical simulation.The calculated result of the composition evolution of steel,slag and inclusion is in consistent with the experimental result.Meanwhile,the influence of different slag compositions on inclusion compositions was also calculated using the present model.It is indicated that Al2O3 in inclusions increased with the increasing slag basicity and the decreasing SiO2 content in slag.T.O.in the molten steel could be largely influenced by the gas flow rate and the inclusion diameter.The calculation results also showed that as the diameter of incluion originated from slag entrapment increases,the rate of content change of Al2O3 and SiO2 in inclusions first increases then decreases.The relationship between the mass transfer coefficient and the stirring energy dissipation in the molten steel was obtained by the kinetic model between the MgO refractory and the molten steel.The calculation result showed that the mass transfer coefficient of Mg in the molten steel was kref_Mg=(5.6-4.7×e-0 0966?)×10-4.According to the calculation,the refractory dissolution is mainly caused by the reaction among[Al],[O]and refractory when the dissolved aluminum is higher than the critical value.And the decomposing of MgO refractory occurred when the Al content in steel is lower than the critical aluminum content.