首钢A高炉炉渣降低MgO的热力学分析

为了研究首钢A高炉炉渣降低MgO的可行性，利用FactSage热力学软件，从理论上解析首钢A高炉炉渣中MgO对固相析出温度和黏度的影响。研究发现，A高炉炉渣固相析出温度在1 400 ℃左右，炉渣在高炉炉缸中全为液相并具有较好的流动性。1 500 ℃下，现有炉渣组分在相图中液相区，若MgO含量降低，炉渣仍处在液相区。MgO质量分数在2.87%～7.37%区间变化时，随MgO含量升高，固相析出温度增加；MgO质量分数升高1%，炉渣固相析出温度升高约3.73 ℃。随MgO含量升高，炉渣黏度降低。1 500 ℃下，MgO质量分数升高1%时，炉渣黏度降低0.014 Pa·s。分析认为，炉缸热状态较好(铁水温度在1 480 ℃以上)时，适当降低MgO质量分数至6%，炉渣黏度不会受较大影响；炉缸热状态较差(铁水温度在1 480 ℃以下)时，不建议降低MgO含量。

Thermodynamic analysis of reducing MgO content in slag for blast furnace A in Shougang

With the trend of large- size of blast furnace, the higher demands for the slag property, especially the mobility and stability in high temperature were put forward in production. The appropriate melting temperature and viscosity were required for the blast furnace smelting. Based on the thermodynamic software FactSage, the effects of the MgO content on the liquidus temperature and viscosity of the slag for blast furnace A of Shougang were analyzed. The results showed that liquidus temperature is about 1 400 ℃ of the slag for blast furnace A, and the slag was fully liquid and had a good mobility. The slag composition was in the liquid phase region at 1 500 ℃. If reducing the MgO content, the slag was still in the liquid phase region. When the MgO mass fraction was in the range of 2.87%- 7.37%, the liquidus temperature increased with the increase of the MgO content. And when increasing the MgO mass fraction of 1%, the slag liquidus temperature increased 3.73 ℃. The slag viscosity reduced with increasing the MgO content. And the slag viscosity reduced 0.014 Pa·s with increasing the MgO mass fraction of 1%. It was considered when the hearth heat condition was good(hot metal temperature above 1 480 ℃), reducing the MgO mass fraction to 6% had little impact on the slag viscosity. But when the hearth heat condition was bad(hot metal temperature is below 1 480 ℃), reducing the reduction of the MgO content was not recommended.