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<p>Given the limitations of traditional sintering in terms of high energy consumption and pollution, electromagnetic induction sintering emerges as a promising carbon-free alternative. The electrical conduction behavior, phase composition, and microstructure of the Fe<sub>2</sub>O<sub>3</sub> polycomponent system (doped with MgO, Al<sub>2</sub>O<sub>3</sub>, SiO<sub>2</sub>, and CaO)&#xa0;were investigated to explore the fundamental theory and application potential of electromagnetic induction sintering. Experimental results show that MgO and CaO doping suppress the increase in Fe<sub>2</sub>O<sub>3</sub> resistance. At 600&#xa0;°C, the resistance of Fe<sub>2</sub>O<sub>3</sub> decreased from 6.89 × 10<sup>4</sup> to 1.88 × 10<sup>4</sup>&#xa0;Ω with increasing MgO content (a 72.71% reduction). Similarly, as CaO doping rose from 0.5% to 2.0%, resistance dropped from 8.23 × 10<sup>4</sup> to 3.81 × 10<sup>4</sup>&#xa0;Ω (53.70% reduction). In contrast, Al<sub>2</sub>O<sub>3</sub> and SiO<sub>2</sub> doping increased resistance: Al<sub>2</sub>O<sub>3</sub> content (0.5%–3.5%) raised resistance by 88.06%, while SiO<sub>2</sub> (2.0%–8.0%) increased it by 71.40%, exceeding pure Fe<sub>2</sub>O<sub>3</sub>. Conduction activation energy analysis revealed that MgO and CaO lowered activation energy, whereas Al<sub>2</sub>O<sub>3</sub> and SiO<sub>2</sub> raised it, hindering electron migration. X-ray diffraction indicated that MgO doping promoted the transformation of Fe<sub>2</sub>O<sub>3</sub> to Fe<sub>3</sub>O<sub>4</sub> and enhanced conductivity via grain growth. Al<sub>2</sub>O<sub>3</sub> induced lattice distortion,&#xa0;and above 2.5% doping, cracks and porosity increased. SiO<sub>2</sub> formed silicate phases, causing liquid-phase grain bonding, and&#xa0;excessive doping harmed conductivity. CaO improved densification by generating a calcium ferrite phase. </p>

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Transition from carbon-based to electric induction sintering of iron ore: phase evolution and conductivity kinetics in multicomponent Fe2O3 systems doped with gangue oxides

  • 期刊论文

  • 发表日期：

    2026年7月9日

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  • Ren-De Chang,
  • Cheng-Yi Ding,
  • Yi-Bin Wang,
  • Rui-Rui Wei,
  • Hong-Ming Long,
  • Xiao-Qing Xu,
  • Jian He,
  • Qing-Min Meng,
  • Tie-Jun Chun

摘要

Given the limitations of traditional sintering in terms of high energy consumption and pollution, electromagnetic induction sintering emerges as a promising carbon-free alternative. The electrical conduction behavior, phase composition, and microstructure of the Fe2O3 polycomponent system (doped with MgO, Al2O3, SiO2, and CaO) were investigated to explore the fundamental theory and application potential of electromagnetic induction sintering. Experimental results show that MgO and CaO doping suppress the increase in Fe2O3 resistance. At 600 °C, the resistance of Fe2O3 decreased from 6.89 × 104 to 1.88 × 104 Ω with increasing MgO content (a 72.71% reduction). Similarly, as CaO doping rose from 0.5% to 2.0%, resistance dropped from 8.23 × 104 to 3.81 × 104 Ω (53.70% reduction). In contrast, Al2O3 and SiO2 doping increased resistance: Al2O3 content (0.5%–3.5%) raised resistance by 88.06%, while SiO2 (2.0%–8.0%) increased it by 71.40%, exceeding pure Fe2O3. Conduction activation energy analysis revealed that MgO and CaO lowered activation energy, whereas Al2O3 and SiO2 raised it, hindering electron migration. X-ray diffraction indicated that MgO doping promoted the transformation of Fe2O3 to Fe3O4 and enhanced conductivity via grain growth. Al2O3 induced lattice distortion, and above 2.5% doping, cracks and porosity increased. SiO2 formed silicate phases, causing liquid-phase grain bonding, and excessive doping harmed conductivity. CaO improved densification by generating a calcium ferrite phase.