PRACTICE OF HIGH EFFICIENCY DEPHOSPHORIZATION OF LIME POWDER BY BLOWING IN ELECTRIC FURNACE
Dephosphorization is one of the core problems in steelmaking process.Dephosphorization in EAF smelting process is mainly through strengthening mass transfer diffusion to promote the oxidation of phosphorus at the slag-liquid steel interface.Shan Steel Laiwu Branch 50 t electric furnace mainly produces superior special steel,most of the steel requires phosphorus content＜0.02％,some steel requires phosphorus content ≤0.010％,the task of dephosphorization of electric furnace is heavy,there are many times in the production process to add lime,affecting the production efficiency.In view of the large temperature drop and long smelting time caused by the addition of lime and dephosphorization,it is difficult to meet the problems of efficient smelting of low-phosphorus steel by electric furnace,by adding a lime powder device on the electric furnace platform,adding bulk lime powder in bags into the powder spray tank,in the early stage of electric furnace smelting,the temperature in the furnace is 1 470～1 500 ℃ and the mode of low oxygen.The lime powder with the particle size of 0～10 mm was sprayed into the electric furnace to improve the dephosphorization efficiency in the early smelting stage.After the powder spraying,adjust the oxygen supply to 5 000～5 500 Nm3/h,stir for dephosphorization,and achieve efficient dephosphorization.The smelting practice results of 42CrMoA and 22CrMoH steel show that the phosphorus content is reduced by 0.007 3％～0.007 5％,the lime consumption is reduced by 7.3～8.0 kg/t steel,the average smelting period is shortened by 4.2～4.6 min,and the smelting effect is good.
electric furnacelime powderinjection devicedephosphorizationsmelting cycle
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