The Dynamic Interfacial Oxygen Potential Between Iron-Carbon Droplets and Oxidizing Slag

The dynamic nature of the interfacial oxygen potential during dephosphorization was investigated based on the concept that PO2$$ P_{{{\text{O}}_{2} }} $$ at the interface between slag and liquid metal is determined by the balance between oxygen supply from reducible oxides in the slag and oxygen consumption by alloying elements in the metal. Combining this approach with the knowledge that at the phosphorus reversion point the interfacial oxygen potential can be determined from the bulk phosphorus partition ratio, the mass transfer coefficient for FeO, kFeO, was determined for different slags and found to increase with increasing FeO content. In foamy slags, kFeO was found to be a linear function of slag liquid fraction. Equating the mass transfer rate of FeO in the slag with decarburization rate, the dynamic interfacial oxygen potential was calculated over the course of the reaction, and its effect on the rate determining step for dephosphorization was evaluated.