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The Chinese Journal of Process Engineering ›› 2025, Vol. 25 ›› Issue (5): 510-521.DOI: 10.12034/j.issn.1009-606X.224318

• Research Paper • Previous Articles     Next Articles

Effect of addition of hematite and limonite on oxidation kinetics and roasting performance of fluxed magnetite pellets

Wei RAN1,  Jian PAN1,2,  Congcong YANG1,2*,  Deqing ZHU1,2,  Zengfu WU3,  Qinghua LIU3,  #br# Qian ZHANG1   

  1. 1. School of Minerals Processing and Bioengineering, Central South University, Changsha, Hunan 410083, China 2. Low Carbon and Hydrogen Metallurgy Research Center, Central South University, Changsha, Hunan 410083, China 3. Northern Engineering and Technology Corporation (Dalian), MCC, Dalian, Liaoning 116600, China
  • Received:2024-10-14 Revised:2024-11-18 Online:2025-05-28 Published:2025-05-30
  • Contact: YANG Cong-cong CongcongYANG smartyoung@csu.edu.cn

配加赤-褐铁矿对熔剂性磁铁矿球团氧化动力学和焙烧性能的影响

冉微1， 潘建1,2， 杨聪聪1,2*， 朱德庆1,2， 吴增福3， 刘庆华3， 张倩1   

  1. 1. 中南大学资源加工与生物工程学院，湖南 长沙 410083 2. 中南大学低碳与氢冶金研究中心，湖南 长沙 410083 3. 中冶北方(大连)工程技术有限公司，辽宁 大连 116600
  • 通讯作者: 杨聪聪 smartyoung@csu.edu.cn
  • 基金资助:
    中国宝武低碳冶金创新基金资助项目

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Abstract: Firstly, simultaneous thermal analysis (TG-DSC) was employed to uncover the impacts of hematite-limonite and finely ground limestone on the oxidation process of magnetite. It was discovered that the decomposition and escape of calcium carbonate in limestone and the crystallization water in limonite inhibited the oxidation of magnetite. Subsequently, the influence mechanism of adding finely ground hematite-limonite on the oxidation kinetics of fluxed magnetite pellets under different ore blending conditions was emphatically studied. And the internal relationship between the oxidation degree of pellets and their roasting performance under the process conditions simulating the belt roaster was revealed. The results indicated that when the oxidation temperature was within the range of 850~1000℃, the pellets with different ratios of hematite-limonite were controlled by chemical reactions in the early stage of the oxidation reaction. It was also found that the higher the addition of hematite-limonite, the higher the apparent activation energy. Moreover, the apparent activation energy in the early oxidation stage of pellets with limonite added was higher than that of pellets with an equal amount of hematite added at the same basicity. The main reason for this was that the removal of crystallization water from the former pellets took away part of the heat and reduces the oxygen partial pressure during the heating process. Unlike the traditional grate kiln process, for the belt roaster, the oxidation degree of the pellets in the preheating stage was not necessarily the higher the better. When the oxidation degree of the pellets in the preheating stage was too high, it led to less heat being provided by the oxidation of Fe3O4 in the roasting stage, which was detrimental to the improvement of the pellets' strength.

Key words: oxidation kinetics, hematite and limonite, fluxed pellets, magnetite, roasting performance, belt roaster

摘要： 采用同步热分析(TG-DSC)揭示了赤-褐铁矿、细磨石灰石对磁铁矿氧化过程的影响，发现石灰石中碳酸钙和褐铁矿中结晶水的分解和逸出会抑制磁铁矿的氧化。考察了配加细磨赤-褐铁矿对不同配矿条件下熔剂性磁铁矿球团氧化动力学的影响机制，并揭示了模拟带式焙烧机工艺条件下球团氧化度与其焙烧性能之间的内在关联。结果表明，在850~1000℃，配加了不同含量赤-褐铁矿的球团在氧化前期均受化学反应控制；赤-褐铁矿的配加量越高，表观活化能越高，且在碱度相同时，配加褐铁矿的球团氧化前期活化能比配加等量赤铁矿的球团高，主要原因是前者在加热过程中结晶水的脱除带走了部分热量，降低了氧分压。不同于传统链篦机-回转窑工艺，带式焙烧机预热段的球团氧化度并非越高越好，球团预热阶段氧化度过高，导致焙烧阶段因Fe3O4氧化提供的热量较少，反而不利于提高球团的强度。

关键词: 氧化动力学, 赤-褐铁矿, 熔剂性球团, 磁铁矿, 焙烧特性, 带式焙烧机