Phosphate enrichment mechanism in CaO-SiO2-FeO-Fe2O3-P2O5 steelmaking slags with lower binary basicity

The addition of silica to steelmaking slags to decrease the binary basicity can promote phosphate enrichment in quenched slag samples. In this study, we experimentally investigated phosphate enrichment behavior in CaO-SiO2-FeO-Fe2O3-P2O5 slags with a P2O5 content of 5.00% and the binary basicity B ranging from 1.0 to 2.0, where the (%Fe (t) O)/(%CaO) mass percentage ratio was maintained at 0.955. The experimental results are explained by the defined enrichment degree of solid solution 2CaO center dot SiO2-3CaO center dot P2O5 (C2S-C3P), where is a component of the developed ion and molecule coexistence theory (IMCT)-N (i) model for calculating the mass action concentrations N (i) of structural units in the slags on the basis of the IMCT. The asymmetrically inverse V-shaped relation between phosphate enrichment and binary basicity B was observed to be correlated in the slags under applied two-stage cooling conditions. The maximum content of P2O5 in the C2S-C3P solid solution reached approximately 30.0% when the binary basicity B was controlled at 1.3.