70 t顶底复吹转炉石灰石双渣脱磷工艺实践
Practice of Limestone Double Slag Dephosphorization Process in 70 t Top-Bottom Combined Blowing Converter

70 t顶底复吹转炉石灰石双渣脱磷工艺实践表明：转炉石灰石双渣工艺一次倒炉最佳温度控制范围为1370℃~1420℃，碱度范围1.7~2.1，w(FeO)范围17%~21%，一倒脱磷率平均为54.2%；脱碳阶段使用石灰石造渣，产生的CO₂提高熔池搅拌强度优化脱磷动力学条件；终渣碱度控制在3.2~3.5，w(FeO)含量控制在13.8%~14.9%，出钢温度在1640℃~1660℃时，脱磷率平均73.5%；相比脱磷期加入石灰石，脱碳期加石灰石双渣工艺钢铁料消耗降低约0.9 kg/t；与石灰双渣法相比，石灰石双渣工艺降本约7.31元/t。
The practice of Limestone double slag dephosphorization process in 70 t top-bottom combined blowing converter shows that the optimal first deslagging temperature range was 1370？C~1420？C, when the basicity was controlled at 1.7~2.1, the w(FeO) in slag at 17%~21%, the average dephosphorization rate was 54.2% in limestone double slag dephosphorization process. The CO₂ generated in decarburization period in which adding limestone improved the stirring intensity of bath and dephosphorization kinetic conditions. The average dephosphorization rate was 73.5% when the basicity of final slag was controlled at 3.2~3.5, the w(FeO) in slag at 13.8%~14.9%, and the tapping temperature was 1640？C~1660？C. Compared with adding limestone in dephosphorization period, the consumption of hot metal and scrap of double slag, adding limestone in the process of decarburization period was reduced by about 0.9 kg/t; Compared with lime double slag process, the cost of limestone double slag process was reduce about 7.31 yuan per ton steel.