Abstract: By testing in a 15 kg vacuum induction furnace it is obtained that there is obvious dephosphorization effect by respectively adding Li₂O, CaF₂, Na₂O and K₂O in CaO base dephosphorization slag series, of them the CaO base slag containing 5% 10% Li₂O has optimum dephosphorization results. The results of commercial pilot production of 120 t top and bottom combined blowing converter with double slag operation show that as compared with the earlier stage slag without adding lepidolite (/% : 34.58 kg/t lime, 5.41 kg/t dolomite and 3.13 kg/t sinter) in earlier stage of dephosphorization based on adding 31.46 kg/t lime, 3.70 kg/t dolomite and 0.70 kg/t sinter, with adding 13.88 kg/t lepidolite mineral (/% : 56.41SiO_2, 3.80FeO, 4.50Na₂O, 4.17K₂O, 3. 18Li₂O) the oxidizability of converter end slag is lower, the average dephosphorization rate and phosphorus equilibrium distribution coefficient of converter semi-steel is respectively 1.67 time and 2.81 times that without adding lepidolite, the converter end dephosphorization rate and phosphorus equilibrium distribution coefficient is respectively 1.02 times and 1.47 times that without adding lepidolite, as compared with nonadding lepidolite the converter blowing end [P] decreases from 0.009%-0.011% to 0.005%-0.006% to meet the requirement of ultra-low phosphorus steel.

Key words: 120 t Top and Bottom Combined Blowing Converter, Dephosphorization Slag Series, Ultra-Low Phosphorus Steel, Alkali Metal Oxides, Lepidolite Mineral, Dephosphorization

摘要： 通过15 kg真空感应炉试验得出CaO基脱磷渣系中分别添加Li₂O、CaF₂、Na₂O、K₂O后均有明显的脱磷效果,其中Li₂O含量5%~10%时脱磷效果最佳。120 t顶底复吹转炉双渣操作的工业试验结果表明,脱磷前期在加31.46 kg/t石灰、3.70 kg/t白云石和0.70 kg/t烧结矿的基础上添加13.88 kg/t锂云母矿（/%:56.41SiO_2，3.80FeO，4.50Na₂O，4.17K₂O，3.18Li₂O）较未加锂云母矿的渣料（34.58 kg/t石灰,5.41 kg/t白云石,3.13 kg/t的烧结矿）转炉终点渣氧化性低,转炉半钢的脱磷率和磷平衡分配比的平均值分别是未加锂云母矿的1.67倍和2.81倍,转炉终点的脱磷率和磷平衡分配比的平均值是未加锂云母矿的1.02倍和1.47倍,与未加锂云母矿相比,转炉吹炼终点[P]可由0.009%~0.011%降低到0.005%~0.006%,能够满足超低磷钢生产要求。

关键词: 120 t顶底复吹转炉, 脱磷渣系, 超低磷钢, 碱金属氧化物, 锂云母矿, 脱磷