Abstract
The rate of oxidation of C in Fe-C, Fe-C-Si and Fe-C-P melts ( [%C] = 4.4 ) by FeO in Li2O-CaO-SiO2 slag has been investigated under the condition of mechanical stirring at 1300°C. The initial concentration of FeO in the slag was varied from 4.6 to 20% and those of Si and P in the melt were varied from 0.004 to 0.33% and from 0 to 0.1%, respectively. In the experiment for investigating the effect of P in the slag on the C oxidation, the initial concentration of P in the slag was changed in the range of 02%. It is found that the C oxidation rate greatly reduces when a small amount of P is added to the slag while P in the metal has no significant effect on the C oxidation. The rate of C oxidation decreases with increasing Si concentration in the metal.
A mathematical reaction model is proposed for the oxidation of C in the metal by FeO in the slag. The model assumes the existence of CO bubbles in the slag-metal interfacial region. Three rate determining steps are taken into account, namely chemical reaction at the gas-slag interface, mass transfer of CO2 in the bubble and chemical reaction at gas-metal interface. The experimental result is in good agreement with that calculated from the model.
