210 t转炉双渣法冶炼深冲钢DC04的脱磷工艺实践

通过热力学计算得出转炉双渣法前期脱磷最佳温度为1 320~1 355℃,前期渣碱度宜为1.3~1.6,并在210 t顶底复吹转炉进行4炉DC04钢工业试验。结果表明,通过留渣量60%~80%的留渣操作,吹炼3~4 min进行倒渣操作,加入生白云石10 kg/t,球团15kg/t,前期渣样组成为33%~39%CaO,20%~25%SiO₂(碱度1.3~1.6),后期二次造渣加石灰16 kg/t,球团15kg/t和轻烧白云石10 kg/t,后期渣样组成44%~47%CaO,≤15%SiO₂(碱度2.85~3.20),使双渣法出钢平均[P]为0.014%,双渣法[Mn]收得率≤30%,前期渣中TFe含量为8.0%~12.0%,对后期渣中TFe含量影响较小。

Practice of Dephosphorization Process in 210 t BOF Steelmaking for Deep-Drawing Steel DC04 by Double Slag Method

According to thermodynamic calculation it is obtained that by BOF double slag method in earlier stage the optimum temperature for dephosphorization is 1 320 ~ 1 355 ℃ and the suitable basicity of slag is 1.3 ~ 1.6, and the commercial production test of 4 heats of steel DC04 by 210 t top and bottom combined blowing converter has been carried out. Results show that with the controlling measures including 60% ~80% slag amount heels by remaining slag operation, blowing for 3 ~4 min then carrying out the skimming earlier slag operation, and adding green dolomite 10 kg/t and pellet 15 kg/t  ingredient of earlier slag sample being 33% ~39% CaO and 20% 〜25% SiO₂ (basicity L 3 〜1. 6) , in later stage secondary slagging adding lime 16 /t, pellet 15 kg/t and light-burned dolomite 10 kg/t, ingredient of later slag sample being 44% ~47% CaO and ≤15% SiO₂ (basicity 2. 85 - 3. 20) , during tapping by double slag method the average [P] is 0. 014% , the yield of [ Mn ] is ≤30% , and the TFe content in slag in earlier stage is 8. 0% ~ 12% , that has not appreciable influence on the TFe content in slag in later stage.