A kinetic model to predict the compositions of metal, slag and inclusions during ladle refining: Part2. condition to control the inclusion composition

A kinetic model to simulate the reactions in a ladle furnace was developed in the previous paper. The following parameters were considered in this model; (1) ratio of the entrapment of slag in the molten steel, (2) ratio of the floatation of the deoxidation products and inclusions originating from the slag, (3) ratio of the agglomeration of deoxidation products with inclusions originating from the slag and (4) ratio of the volume of the bulk zone to the total volume of molten steel and that of slag phase. These parameters were optimized using sensitivity calculation by comparison with operational results as the parameters affected the amount and composition of inclusions. Then, the method to suppress the formation of MgO·Al²O³ spinel-type inclusion was discussed using the optimized parameters. The calculated results showed that the formation of MgO·Al²O ³spinel-type inclusion could be suppressed by optimizing the additional amount of Al, initial content of MgO in the slag, and slag basicity in addition to the Ca treatment. The changes in the inclusions calculated using the kinetic model were in good agreement with those predicted by the phase stability diagram. The developed model was useful for optimizing the operation of a ladle furnace.