2009 Volume 95 Issue 3 Pages 268-274
The role of 2CaO·SiO2 phase on the formation of P2O5 condensed phase should be clarified to elucidate the microscopic dephosphorization mechanisms and to improve the hot metal dephosphorization efficiency by using CaO-based FeOx–CaO–SiO2–P2O5 multi phase flux. In the present study, solid 2CaO·SiO2 piece was reacted with molten FeOx–CaO–SiO2–P2O5 slag for 1 to 60 s at 1673K, and the reaction interface between solid 2CaO·SiO2 and molten FeOx–CaO–SiO2–P2O5 slag was observed and analyzed by SEM and EDS.
The dissolution of 2CaO·SiO2 into the molten slag and the penetration of molten slag into solid 2CaO·SiO2 simultaneously occurred. The 2CaO·SiO2–3CaO·P2O5 was formed from solid 2CaO·SiO2 and P2O5 in the slag. On the other hand, during the penetration of slag, the P2O5 in the slag reacted with 2CaO·SiO2 to form 2CaO·SiO2–3CaO·P2O5 phase. The P2O5 content of 2CaO·SiO2–3CaO·P2O5 phase existing in solid 2CaO·SiO2 region was lower than that observed at the 2CaO·SiO2 saturated liquid phase region because of the lower P2O5 content of penetrating slag than that of 2CaO·SiO2 saturated liquid slag. The 2CaO·SiO2 saturated liquid slag region and the region where P2O5 condensed phase was observed at the interface expanded with time.
