To increase the utilization fraction of V-Ti-Magnetite ore in the burden of the blast furnace over 80 pct, the technology of “replacing CaO with MgO” was discussed. The high content of TiO2-bearing raw materials leads to a super high TiO2 content in the blast furnace slag, which affects the normal operation of the blast furnace ironmaking process. The physicochemical properties of TiO2-bearing blast furnace slag such as viscosity are fundamentally determined by the high temperature and structure of the slag. In this study, Raman spectroscopy focusing on the effect of TiO2 and MgO/CaO ratio on the structure of super high TiO2-bearing blast furnace slag was performed. The results indicate that most of the Ti4+ ions are in the tetrahedron unit, and a few of Ti4+ ions are in the octahedron unit with a coordination number of six; this is confirmed by the presence an emission spectrum related to Ti-O stretching vibrations at wavenumbers less than 700 cm−1. The mole fraction of the band below 700 cm−1, which is related to the coupling of Al-O stretch vibration and the Ti-O stretch vibrations of Ti4+ in sixfold coordination, increased from 0.14 to 0.19 as the TiO2 content in CaO-SiO2-TiO2-MgO-Al2O3 slag increased from 20 to 34 mass pct. The (Q3)2/(Q2) ratio that is proposed as an index for the degree of polymerization (DOP) of melts decreased from 5.72 × 10−3 to 1.0 × 10−3 as the TiO2 content increased. Increasing the MgO/CaO ratio caused a slight decrease in the fraction of the bands below 700 cm−1 and resulted in the decrease of the (Q3)2/(Q2) ratio; thus, the DOP of the melts increased with increasing MgO/CaO ratio. The quantitative relationship, ln(η) = 0.91 + 0.11·ln((Q3)2/(Q2)), between the high-temperature structure information and the viscosity of TiO2-bearing blast furnace slag was established.

中文翻译：

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炉渣中含有超高 TiO2 的高炉炼铁工艺：炉渣的高温结构

为使高炉炉料中钒钛磁铁矿的利用率提高到80%以上，探讨了“MgO替代CaO”技术。含TiO2原料的高含量导致高炉渣中TiO2含量超高，影响高炉炼铁工艺的正常运行。含TiO2高炉渣的粘度等理化性质从根本上是由渣的高温和结构决定的。在这项研究中，拉曼光谱重点关注 TiO2 和 MgO/CaO 比对超高含 TiO2 高炉渣结构的影响。结果表明，大部分Ti4+离子处于四面体单元中，少数Ti4+离子处于配位数为6的八面体单元中；这通过在波数小于 700 cm-1 处存在与 Ti-O 伸缩振动相关的发射光谱而得到证实。随着CaO-SiO2中TiO2含量的增加，与Al-O伸缩振动和Ti4+六重配位的Ti-O伸缩振动耦合有关的700cm-1以下能带的摩尔分数从0.14增加到0.19 -TiO2-MgO-Al2O3 炉渣从 20 质量 pct 增加到 34 pct。随着 TiO2 含量的增加，作为熔体聚合度 (DOP) 指标的 (Q3)2/(Q2) 比值从 5.72 × 10-3 降低到 1.0 × 10-3。增加 MgO/CaO 比值导致低于 700 cm-1 的谱带分数略有下降，导致 (Q3)2/(Q2) 比值下降；因此，熔体的 DOP 随 MgO/CaO 比的增加而增加。数量关系，ln(η) = 0.91 + 0。