The induration process and oxidation kinetics of Hongge vanadium titanium-bearing magnetite (HVTM) pellets have been investigated by employing X-ray diffraction, scanning electron microscope, energy-dispersive spectroscopy, thermogravimetric and differential thermal analysis and thermogravimetric and differential scanning calorimetry. The results indicated that HVTM was a high-chromium vanadium-bearing titanomagnetite containing 1.48 wt-% Cr2O3, and the crystal stock strength was 625 N. The compressive strength of HVTM pellets could be improved by increasing the roasting temperature and roasting time. Under the optimum conditions of oxidation roasting at 1200°C for 15 min, the compressive strength was found to be 2893 N. The phase transformations of the valuable elements could be described as follows: Fe3O4→Fe2O3; Fe2VO4→(Cr0.15V0.85)2O3; Fe2.75Ti0.25O4→FeTiO3→Fe9TiO15; FeCr2O4→(Fe0.6Cr0.4)2O4, Fe0.7Cr1.3O3, (Cr0.15V0.85)2O3. Three stages were identified during the induration process: initial oxidation, later oxidation, and haematite re-crystallisation, poly-crystallisation and induration. The development of strength mainly occurred in the last stage. Kinetic parameters of the oxidation process were determined from heating experiments. The results showed that the average value of activation energy was calculated to be 69.33 kJ mol−1 by the Flynn–Wall–Ozawa methods. This study aims to provide theoretical and technical bases for the effective utilisation of HVTM ore for use in either blast furnaces or shaft furnaces.

中文翻译：

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红格含钒钛磁铁矿球团氧化硬化过程及动力学

采用X射线衍射、扫描电子显微镜、能量色散谱、热重和差热分析以及热重和差示扫描量热法研究了红格含钒钛磁铁矿（HVTM）球团的硬化过程和氧化动力学。结果表明，HVTM 是一种含 1.48 wt-% Cr2O3 的高铬钒钛磁铁矿，晶体坯料强度为 625 N。提高焙烧温度和焙烧时间可以提高 HVTM 球团的抗压强度。在1200°C氧化焙烧15 min的最佳条件下，抗压强度为2893 N。有价值元素的相变可描述为：Fe3O4→Fe2O3；Fe2VO4→(Cr0.15V0.85)2O3；Fe2。75Ti0.25O4→FeTiO3→Fe9TiO15；FeCr2O4→(Fe0.6Cr0.4)2O4、Fe0.7Cr1.3O3、(Cr0.15V0.85)2O3。在硬化过程中确定了三个阶段：初始氧化、后期氧化和赤铁矿重结晶、多晶和硬化。实力的发展主要发生在后期。氧化过程的动力学参数由加热实验确定。结果表明，通过Flynn-Wall-Ozawa方法计算的活化能平均值为69.33 kJ mol-1。本研究旨在为高炉或竖炉有效利用HVTM矿石提供理论和技术基础。和赤铁矿重结晶、多晶和硬化。实力的发展主要发生在后期。氧化过程的动力学参数由加热实验确定。结果表明，通过Flynn-Wall-Ozawa方法计算的活化能平均值为69.33 kJ mol-1。本研究旨在为高炉或竖炉有效利用HVTM矿石提供理论和技术基础。和赤铁矿重结晶、多晶和硬化。实力的发展主要发生在后期。氧化过程的动力学参数由加热实验确定。结果表明，通过Flynn-Wall-Ozawa方法计算的活化能平均值为69.33 kJ mol-1。本研究旨在为高炉或竖炉有效利用HVTM矿石提供理论和技术基础。