1994 Volume 34 Issue 8 Pages 649-656
A kinetic study has been made on decarburization of molten iron of low carbon and oxygen concentrations with solid oxides. Electrolytic iron was melted in a MgO, Al2O3 or CaO crucible. The mass of iron and the initial carbon concentration were varied between 137 and 627 g and between 30 and 480 ppm. The initial oxygen concentration was below 50 ppm, and oxygen for the decarburization was supplied by the crucible oxide. Experiments were made with blowing argon gas (1000 Ncm3/min) onto the melt surface at 1580°C.
The rate of decarburization decreases in the order of MgO, Al2O3 and CaO and is almost independent of the stirring condition of the bath. For the carbon concentration >100 ppm, the rate of decarburization does not change with the initial carbon concentration. From these results, it is considered that the rate is controlled by the dissociation reaction of the oxide. For the carbon concentration <100 ppm. The rate decreases with decreasing carbon concentration. In this case, the rate is presumed to be controlled by the dissociation reaction of oxide, formation reaction of CO at crucible-melt interface and CO mass transfer. A mathematical model is proposed to explain the rate of decarburization.