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

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