Kinetic Study of Dephosphorization of Liquid Iron with Solid CaO

Abstract

A kinetic study is made of dephosphorization of liquid iron-phosphorus alloy with solid CaO and oxidizing gas. Iron-phosphorus alloy is melted in CaO crucible at 1600°C and then phosphorus in molten iron is oxidized by H₂-H₂O gas mixture (PH₂O/PH₂≈0.20-0.65).
The results are summarized as follows.
1) The maximum value and the minimum value of oxygen content of molten Fe-P alloy appear during dephosphorizing.
2) Dephosphorization reaction is divided into three periods; at the first period, chemical reaction is rate limiting step, in the second period, dephosphorization rate depends on the rate of oxygen supply from gas to molten iron, and transport of phosphorus in solid CaO is rate limiting step in the final period.