The kinetics of the silicon oxidation of the hot metal with the iron oxide slag was studied. The experiment was carried out by the high frequency induction furnace using a graphite susceptor and a fused magnesia crucible. Three ratedetermining steps were found depending upon the FeO content in the slag. The rate of silicon oxidation oxidation was controlled by the silicon transfer in the metal phase when FeO content in the slag was more than 40%. In this region, the rate of silicon oxidation was not affected by carbon and manganese oxidations. When FeO in the slag reduced to less than 40 %, the rate of silicon oxidation was controlled by transfers of silicon in the metal and FeO in the slag. In this region the rate of silicon oxidation was suddenly slowed down. Further, it was assumed that under the FeO content less than 10% the rate of silicon oxidation was controlled by the transfer of FeO in the slag phase. In the industrial experiment, these results were also confirmed, and significance of stirring was further recognized.
