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<p>H<sub>2</sub> has been identified as a clean and promising reductant, offering an environmentally friendly alternative to C and CO for iron ore reduction. The H<sub>2</sub> reduction of ordinary iron ores has been widely studied and industrially practiced, but the H<sub>2</sub> reduction of vanadium titanomagnetite ores, a valuable mineral, is challenging and remains an area of active investigation. In this study, isothermal reduction experiments of vanadium titanomagnetite pellet (VTP) and ordinary pellet were conducted. The phase transformation and microstructure evolution during the reduction process were systematically characterized by FactSage, X-ray diffraction, electron probe microanalysis, and mercury porosimetry. The results show that the H<sub>2</sub> reduction rate of VTP is significantly higher than CO. The reduction paths by CO and H<sub>2</sub> basically advance along the direction of FeO, and the Fe<sub>2</sub>TiO<sub>4</sub> interspersed with FeO is difficult to be reduced, but the ΔG<sub>m</sub><sup>θ</sup> of H<sub>2</sub> reduction of Fe<sub>2</sub>TiO<sub>4</sub> is lower than that of CO. It was also found that the process of CO reduction is from the periphery to the center, exhibiting a gradual advancement, while the process of H<sub>2</sub> reduction is more periphery and less center, presenting a multi-point blossoming. Furthermore, a large number of micropores (0.1–1&#xa0;μm) are formed during the reduction process, which enlarges the pellet porosity and changes the pore size distribution from single peak to bimodal peak. The micropores generated by H<sub>2</sub> reduction are smaller than CO, leading to a larger porosity of the H<sub>2</sub>-reduced pellet. Through a triple mechanism of lowering the thermodynamic energy barrier, altering the microscopic reduction pattern, and optimizing the pore structure, H<sub>2</sub> weakens the reduction bottleneck of VTP, providing a scientific basis for its industrial application.</p> Graphical Abstract <p></p>

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Comparative Study of Vanadium Titanomagnetite Pellet and Ordinary Pellet Reduced by CO or H2

  • 期刊论文

  • 发表日期：

    2025年8月25日

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  • Chen Yin,
  • Yunpeng Fang,
  • Lei Luo,
  • Yanjun You,
  • Chenguang Bai,
  • Shengfu Zhang,
  • Mao Chen

摘要

H2 has been identified as a clean and promising reductant, offering an environmentally friendly alternative to C and CO for iron ore reduction. The H2 reduction of ordinary iron ores has been widely studied and industrially practiced, but the H2 reduction of vanadium titanomagnetite ores, a valuable mineral, is challenging and remains an area of active investigation. In this study, isothermal reduction experiments of vanadium titanomagnetite pellet (VTP) and ordinary pellet were conducted. The phase transformation and microstructure evolution during the reduction process were systematically characterized by FactSage, X-ray diffraction, electron probe microanalysis, and mercury porosimetry. The results show that the H2 reduction rate of VTP is significantly higher than CO. The reduction paths by CO and H2 basically advance along the direction of FeO, and the Fe2TiO4 interspersed with FeO is difficult to be reduced, but the ΔGmθ of H2 reduction of Fe2TiO4 is lower than that of CO. It was also found that the process of CO reduction is from the periphery to the center, exhibiting a gradual advancement, while the process of H2 reduction is more periphery and less center, presenting a multi-point blossoming. Furthermore, a large number of micropores (0.1–1 μm) are formed during the reduction process, which enlarges the pellet porosity and changes the pore size distribution from single peak to bimodal peak. The micropores generated by H2 reduction are smaller than CO, leading to a larger porosity of the H2-reduced pellet. Through a triple mechanism of lowering the thermodynamic energy barrier, altering the microscopic reduction pattern, and optimizing the pore structure, H2 weakens the reduction bottleneck of VTP, providing a scientific basis for its industrial application.

Graphical Abstract