天铁180t转炉少渣低温高效脱磷冶炼工艺实践

Smelting Process Practice of Less slag Lower Temperature High Efficient Dephosphorization at Tiantie Hot Rolling 180 t Converter

为优化转炉冶炼工艺,对180 t顶底复吹转炉进行少渣低温高效冶炼试验,采用少渣冶炼工艺,即：兑铁→脱磷期冶炼→前期倒渣→脱碳期冶炼→终点出钢,实现了前期渣碱度平均1.91,前期脱磷率平均56.25%,后期渣碱度平均3.02,终点脱磷率平均〉90%,过程石灰、白云石消耗分别降低30%、20%以上。冶炼前期碱度1.5~2.0,熔池温度1 350~1 400℃更有利于铁水中磷的脱除;随着出钢温度和终渣碱度的提高,钢中磷含量增加。

In order to optimize converter melting process, less slag lower temperature high efficient melting test was carried out on 180 t top and bottom blowing converter. Less slag melting process, i.e., hot metal charging → melting during dephosphorization phase → deslagging at early phase → melting during decarburization phase → tapping at end point, realized an average slag basicity of 1.91 at early phase, an average dephosphorization rate of 56.25% at early phase, an average slag basicity of 3.02 at latter phase, an average dephosphorization rate of 90% at end point and the reduction of over 30% and 20% of lime and dolomite consumption respectively. The author points out the basicity of 1.5 ~2.0 at early melting phase and the bath temperature of 1,350 ~1,400 ℃ are favorable for hot metal dephosphorization; phosphorous content at end point tapping will increase with the increase of end point temperature and end slag basicity.