Effect of Na_2O and B_2O_3 on the Distribution of P_2O_5 between Solid Solution and Liquid Phases Slag

摘要

With the development of multiphase slag system for hot-metal treatment to achieve better dephospho-rization efficiency, it is very important to improve the distribution ratio of P_2O_5 between the solid solution (2CaO·SiO_2-3CaO·P_2O_5) and liquid phase slag. This study was carried out to investigate the effects of Na_2O and B_2O_3 on P_2O_5 distribution ratio and morphologies of corresponding solid solutions in CaO-SiO_2-Fe_2O_3-P_2O_5 slag system. The results indicated that the distribution ratio of P_2O_5 would be improved with the increase of Na_2O content due to the formation of (2CaO·SiO_2-Na_2O·2CaO·P_2O_5) solid solution with a similar morphology as that of reference solid solution (2CaO·SiO_2·3CaO·P_2O_5) in the reference slag. While B_2O-3 plays an opposite role, it would not only reduce the phosphorus distribution ratio, but also change the morphology of its corresponding solid solution due to the formation of complex solid solution (2CaO·SiO_2-Ca_(9.93)(P_(5.84)B_(0.16)O_(24)) (B_(0.67)O_(1.79))). Besides, the effect of cooling rate on the size of the solid solution was also studied. It would provide an instructive way for the design of multiphase slag for hot metal treatment.