低硅含镁球团矿还原行为研究

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英文篇名：Study on reduction behavior of low silicon magnesium pellet 作者：王晓哲 ; 张建良 ; 刘征建 ; 刘东辉 ; 刘兴乐 ; 姜春鹤 英文作者：Wang Xiaozhe;Zhang Jianliang;Liu Zhengjian;Liu Donghui;Liu Xingle;Jiang Chunhe;School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing; 关键词：低硅含镁球团矿 ; 还原过程 ; 还原聚集 ; 孔隙分布 英文关键词：low silicon magnesium pellet;;reduction process;;reduction aggregation;;pore distribution 中文刊名：SJQT 英文刊名：Sintering and Pelletizing 机构：北京科技大学冶金与生态工程学院; 出版日期：2018-02-15 出版单位：烧结球团 年：2018 期：v.43 基金：国家自然科学基金重点支持联合基金项目(U1260202) 语种：中文; 页：SJQT201801010 页数：6 CN：01 ISSN：43-1133/TF 分类号：48-53

摘要

本文研究了低硅含镁球团矿在900℃,CO气氛下的还原过程,并通过X射线衍射仪(XRD)和矿相显微镜测定了球团矿在不同还原度时的物相组成和显微形貌。研究结果表明:Fe_2O_3的还原顺序为Fe_2O_3→Fe_3O_4→FeO→Fe,当还原度由0%增加到10%时,Fe_2O_3被还原成Fe_3O_4,且球团矿由外向内均匀还原;当还原度由10%增加到50%时,Fe_3O_4被还原成FeO,并出现还原聚集现象,其原因是球团矿内部孔隙分布不均匀;此后大多数FeO还原为金属Fe。MgFe_2O_4的还原顺序为:MgFe_2O_4→Mg_(0.239)Fe_(0.761)O→Mg_(0.64)Fe_(2.36)O_4→Fe,其还原反应从球团矿还原度为30%时开始,主要原因是MgFe_2O_4较Fe_2O_3难还原。采用未反应核模型对球团矿还原过程进行动力学分析,得到球团矿在还原前期受界面化学反应控速,还原后期既不受混合控速也不受扩散控速。
        The reduction process of the low silicon magnesium pellet at 900 ℃ under pure CO atmosphere was investigated,and the phase composition and microstructure of pellets at different reduction temperatures were also examined by X-ray diffraction( XRD) and mineral microscope. The results show that the reduction order of Fe_2O_3 was Fe_2O_3→Fe_3O_4→FeO→Fe. When the reduction degree increased from 0% to 10%,Fe_2O_3 was reduced to Fe_3O_4 and the pellets were uniformly reduced from outside to inside. When the reduction degree increased from 10% to 50%,Fe_3O_4 was reduced to Fe O and the phenomenon of reductive aggregation occurred. The reason for above is that the internal pore distribution of the pellets is not uniform,subsequently,most of the Fe O was reduced to metal Fe. The reduction order of Mg Fe_2O_4 was MgFe_2O_4→Mg_(0. 239)Fe_(0. 761)O→Mg_(0.64)Fe_(2.36)O_4→Fe,and the reduction started when the reduction degree of pellets arrived at 30%. The reason for this phenomenon is that Mg Fe_2O_4 is more difficult to be reduced than Fe_2O_3. The kinetic analysis by using the unreacted nuclear model indicate that the pellets reduction were controlled by the interfacial chemical reaction at the early stage,but the later reduction process was neither controlled by the internal diffusion nor the mixed control.

引文

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