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过程工程学报 ›› 2023, Vol. 23 ›› Issue (5): 755-762.DOI: 10.12034/j.issn.1009-606X.222148

• 研究论文 • 上一篇    下一篇

不同比表面积铁精矿球团氧化动力学

顾宝澍， 马叙叙， 朱子康， 丁佰根， 罗邦曹， 春铁军*   

  1. 安徽工业大学冶金工程学院，安徽 马鞍山 243032
  • 收稿日期:2022-04-26 修回日期:2022-07-31 出版日期:2023-05-28 发布日期:2023-06-01
  • 通讯作者: 春铁军 springcsu@126.com
  • 基金资助:
    安徽省自然科学基金面上项目;大学生创新创业训练计划

Oxidation kinetics of pellets prepared from iron concentrate with different specific surface areas

Baoshu GU,  Xuxu MA,  Zikang ZHU,  Baigen DING,  Bangcao LUO,  Tiejun CHUN*   

  1. School of Metallurgical Engineering, Anhui University of Technology, Ma'anshan, Anhui 243032, China
  • Received:2022-04-26 Revised:2022-07-31 Online:2023-05-28 Published:2023-06-01
  • Contact: CHUN Tie-jun springcsu@126.com

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摘要： 采用了不同比表面积铁精矿制备球团，分别在不同的温度(1000~1075℃)和时间(0~18 min)内进行了氧化动力学实验。结合基元化学反应和未反应核模型计算球团氧化过程的动力学方程和表观活化能，判断氧化过程的限制性环节。结果表明，随着温度升高和时间延长，氧化率逐渐提高；随着铁精矿比表面积提高，氧化率降低，球团的反应速率常数减小。铁精矿比表面积为849 cm2/g的球团在氧化前期(前3 min)和氧化后期的活化能分别为55.19和26.72 kJ/mol，比表面积为1445 cm2/g的球团在氧化前期(前3 min)和氧化后期的活化能分别为61.73和27.88 kJ/mol，两种球团氧化前期的限制环节为化学反应控制，氧化后期的限制环节为化学反应及气体内扩散混合控制，与未反应核模型得到的结论一致。原料比表面积的提高导致球团的孔隙率下降，影响气体从球团颗粒表面扩散到内部，球团的氧化率和氧化速度下降。

关键词: 比表面积, 球团矿, 氧化动力学, 孔隙率

Abstract: Iron concentrate pellets are an important burden for ironmaking in blast furnaces and high pellets rate is an effective way to reduce carbon emissions. The oxidation kinetics of pellets can be improved to optimize the pellet production process and increase the yield. In this work, the pellets prepared from the iron concentrates with different specific surface areas (SSAs) are oxidized at different temperatures for different time. The result shows that the oxidation rate increases dramatically with increasing temperature and time in the early stage, but increases slowly in the late stage. The apparent oxidation rate constant decreases with the incremental SSA of iron concentrates. The unreacted core model was used to establish the oxidation kinetic equations. For the pellets with SSA of 849 cm2/g, the activation energy is 55.19 kJ/mol in the early oxidation stage and that is 26.72 kJ/mol in the late oxidation stage. For the pellets with SSA of 1445 cm2/g, the activation energy is 61.73 kJ/mol in the early oxidation stage and that is 27.88 kJ/mol in the late oxidation stage. The restrictive steps for the oxidation of the two pellets are consistent. Chemical reaction controls the early stage of oxidation and the late stage of oxidation is controlled both by chemical reaction and gas internal diffusion. High SSA leads to a decrease in the porosity of the oxidized pellets, which affects the gas diffusion from the surface to the interior of the particles. Thus, both the oxidation degree and oxidation rate decrease.

Key words: Specific surface area, pellet, oxidation kinetics, porosity