Kinetic Study on Phosphate Enrichment Behavior in CaO–SiO2–FeO–Fe2O3–P2O5 Steelmaking Slags

The iso-thermal crystallization behavior of phosphate-enriched phase has been experimentally investigated in the rapidly quenched CaO-SiO2-FeO-Fe2O3-P2O5 steelmaking slags under different cooling schedules. The experimental results indicate that increasing endpoint temperature from 1453 to 1533 K and prolonging holding time from 2 to 60 min can result in an increasing tendency of the size of phosphate-enriched phase in the shape of one-dimensional rod. The crystallization kinetics of phosphate-enriched phase in steelmaking slags has been described by Avrami equation. The Avrami constant n was obtained to be 0.472, while the crystallization rate constant k was recommended as In k = 57.40 + 12, 273.96/T - 8.25 In T - 5.5 x 10(-3)T. Thus, the apparent activation energy E of crystallization is recommended as E = 537.60 - 206.015T kJ/mol.