Mechanism of dephosphorization with CaO-SiO2-FetO slags containing mesoscopic scale 2CaO · SiO2 particles

Abstract

Dephosphorization of a liquid Fe-5mass%P alloy with a solid-liquid coexisting flux in which 2CaO · SiO2 particles (20 to 50 μm) are uniformly dispersed in CaO-SiO2-FetO slags has been studied at 1 400°C. For the slag with high SiO2 and low T.Fe contents, the change of slag composition is small and the fraction of 2CaO · SiO2 particles to slag increases slightly during dephosphorization in which the Lpsolid/slag and L pslag/metal values are low. For the slag with moderate SiO2 and high T.Fe contents, the change of slag composition is considerable and the fraction of 2CaO · SiO2 particles to slag increases considerably during dephosphorization in which the Lpsolid/slag and Lpslag/metal values are high at initial period, but these values decrease with time. For the slag with low SiO2 and high T.Fe contents, the change of slag composition is small and the fraction of 2CaO · SiO2 particles to slag decreases slightly during dephosphorization in which the Lpslag/metal and Lpsolid/slag values are high, but Lpsolid/slag value decreases considerably even with small change of slag composition. © 2006 ISIJ.