天铁热轧180t转炉少渣低温高效脱磷冶炼工艺

为优化转炉冶炼工艺，进行了180 t顶底复吹转炉的少渣低温高效冶炼试验，实现前期渣碱度平均为1.91，前期脱磷率平均为56.25%，后期渣碱度平均为3.02，终点脱磷率平均大于90%，过程石灰、白云石消耗分别降低30%、20%以上。得出冶炼前期碱度为1.5~2.0，熔池温度为1350~1400℃更有利于铁水磷的脱除；随终点出钢温度与终渣碱度的提高,终点出钢磷质量分数增加；分析前期的快速化渣有利于铁水磷更多地脱除到前期渣中；冶炼后期的少渣操作容易造成“返干”，是影响后期冶炼效果的关键因素。

Less slag low temperature high efficient dephosphorization process of 180 t BOF in Tianjin Iron Plant

For the purpose of the improvement of converter process, trail experiments of less slag low temperature high efficient dephosphorization process of 180 t top bottom combined blowing BOF were conducted. The results showed that the basicity of the initial slag and the end point slag was 1.91 and 3.02 on average, respectively. And the dephosphorization ratio reached 56.25% in the initial period but more than 90% at the end point. At the same time, the consumption of lime and dolomite dropped by over 30% and over 20%, respectively. It was concluded that the basicity of 1.5-2.0 and temperature of 1350-1400℃ in the initial period did good to the hot metal dephosphorization. And the phosphor content of molten steel increased with the increase of the tapping temperature and the end point slag basicity. The slag that was smelting rapidly in the initial period was helpful for removing more phosphorus form the hot mental to the slag. The slag getting dry, which can be caused by the decrease of slag in the later stage of smelting, was the key factor that affected the end point smelting effect.