Effect of slag/metal interfacial tension on kinetics of dephosphorisation

The effect of interfacial tension on the kinetics of the dephosphorisation of iron has been investigated. X-ray monitoring of the shape of a molten iron droplet in liquid slag showed that there was a marked reduction in the interfacial tension gamma(ms) during periods of rapid mass transfer and an increase in gamma(ms) as the mass transfer process slowed down, similar to that observed for desulphurisation. The dephosphorisation kinetics was found to be first order with respect to phosphorus in the liquid iron and implied that, for the system studied, mass transfer of phosphorus in the slag phase is the Fate controlling step. I&S/1397.