MgO对高碱度高铝烧结矿的影响

 随着钢铁企业高铝铁矿粉使用比例的提高,带来了高炉炉渣黏度增大、渣铁分离困难等一系列问题。采用烧结杯试验,研究了MgO含量增加对高碱度高铝烧结矿经济技术指标、冷强度和冶金性能的影响,采用Nova400 NanoSEM型场发射扫描电子显微镜分析了烧结矿微观结构。试验结果表明,高碱度高铝烧结矿中MgO质量分数从1.72%提高到2.49%时,垂直烧结速度降低4.38 mm/min,利用系数降低0.51 t/(m2·h),低温还原粉化指数增加6.7%;当烧结矿中MgO质量分数为2.11%时,转鼓指数和还原度最高,分别达到61.93%和86.39%;Mg2+主要固溶在磁铁矿晶格中并替代Fe2+,替代的质量分数最高达3.64%,生成的含镁磁铁矿抑制烧结矿降温过程中由Fe₃O₄→Fe₂O₃氧化过程的相变,减少了二次赤铁矿的生成,有利于改善烧结矿的低温还原粉化性能。研究结果可以为改善高碱度高铝烧结矿性能和提高炉渣流动性提供理论指导和参考依据。

Influence of MgO on high basicity high alumina sinter

The increase of the proportion of high Al2O3 content iron ore fine in iron and steel enterprises has brought about a series of problems such as the increase of the viscosity of blast furnace slag and the difficulty of the separation of slag and iron.The effect of increasing MgO content on the technical and economic index,the cold strength,and metallurgical properties of high basicity and high alumina sinter was studied through the sinter pot test.Nova 400 NanoSEM field emission scanning electron microscope was used to analyze the microstructure of the sinter.The experimental results show that when the mass percent of MgO in the sinter with high alkalinity and high aluminum increases from 1.72% to 2.49%,the vertical sintering speed decreases by 4.38 mm/min,the utilization coefficient decreases by 0.51 t/(m²·h),and the low-temperature reduction degradation index increases by 6.7%.When the mass percent of MgO in the sinter is 2.11%,the drum index and the reducibility index are the highest,reaching 61.93%and 86.39%respectively.Mg²⁺ is mainly solid dissolved in the magnetite lattice and replaces Fe²⁺,and the mass fraction of the replacement reaches up to 3.64%.The generated magnesium-containing magnetite inhibits the phase transition from Fe₃O₄ to Fe₂O₃ oxidation process in the sinter cooling process,which reduces the generation of secondary hematite and is conducive to improving the low-temperature reduction degradation performance of the sinter.The research results can provide theoretical guidance and reference for improving the properties of high-basicity and high-alumina sinter and adjusting the fluidity of blast furnace slag.