Rate of Oxidation of Manganese in Liquid Iron by Fe_tO(+MnO)-CaO(+MgO)-SiO₂ Slag

Abstract

The rate of oxidation of manganese in liquid iron by slag was investigated by measuring the change of manganese and oxygen contents of liquid iron covered with Fe_tO(+MnO)-CaO(+MgO)-SiO₂ slag in a magnesia crucible. Experiments were carried out with slags of basicity(=(CaO+MgO)/SiO₂) from 0.37 to 1.49 and Fe_tO content from 24 to 75 wt% at 1600°C.
The oxidation reaction of manganese proceeded comparatively slowly except at the initial period and the equilibrium between liquid iron and slag was not attained within 60 min.
The experimental results were interpreted by the rate equation derived from the assumption that the reaction rate was controlled by the transfer of Mn, O, (MnO) and (FeO) in the boundary layers and the driving force of the reaction varied with proceeding of the reaction. The effect of Fe_tO content of slag on the reaction rate was observed more clearly in the driving force than in the mass transfer coefficient.
The effect of slag basicity on the reaction rate was not clear.