Abstract: According to thermodynamics studying on the balance of dephosphorization and phosphorus reduction, the relationship between pouring temperature and slag basicity at first deslagging for double slag process in 120 t converter smelting low phosphorus steel has been difined. According to calculating phosphorus partition ratio Lp, it gets the influence of basicity、(FeO) on Lp at 1450 °C. and obtains the optimal dephosphorization slag basicity and (FeO) value through Factsage software. The calculation shows that with the increase of slag basicity, the optimal temperature ranges for dephosphorization move to high； the optimal basicity is 2 and (FeO) is 20% ~25% at 1450 °C for first deslagging process.

摘要： 通过脱磷与还原磷的平衡热力学研究,确定了120 t转炉双渣法冶炼低磷钢时最佳一次倒渣温度与碱度之间的关系。通过对磷分配比Lp计算,得到了1450℃下,碱度、(FeO)对其影响。结合热力学软件Factsage,得到最佳的脱磷渣碱度和(FeO)。计算表明,随着炉渣碱度的增大,最佳脱磷温度区间向高温区移动;1450℃下,最佳的第一次倒渣碱度为2,最佳(FeO)为20%～25%。