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采用热失重法在900~1 100℃的范围和CO的体积分数为100%的气氛条件下,对武钢球团矿进行恒温还原实验,通过阿伦尼乌斯(Arrhenius)图和未反应核模型公式分别计算了还原反应的表观活化能和反应速率常数、扩散系数,并判断反应速度的限制性环节,使用场发射扫描电子显微镜(FESEM)和能谱分析(EDS)观察了球团矿在还原过程不同阶段的微观形貌和铁的氧化物的形式,分析了球团矿的反应机理。结果表明:在球团矿还原反应前期至中后期的大部分时间内,反应的限制性环节为界面化学反应,而后期限制性环节改变为固相扩散;球团矿还原是按照铁的氧化物从高级到低级的顺序进行的,采用未反应核模型进行动力学分析是正确的。
The experiment of isothermal reduction of Wuhan Iron and Steel (Group) pellets was carried out by the method of thermogravimetry under the temperature of 900 ~ 1 100 ℃ and the volume fraction of CO of 100%. The Arrhenius diagram and the unreacted core model The formulas were used to calculate the apparent activation energy, the reaction rate constant and the diffusion coefficient of the reduction reaction, respectively, and to determine the limiting part of the reaction rate. The emission of the pellets in the pellets was measured by using field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS) The microscopic morphology and the form of iron oxides at different stages of the reduction process were analyzed and the reaction mechanism of pellets was analyzed. The results show that most of the reaction from the early stage to the middle and late stage of the pellet reduction reaction is the interfacial chemical reaction and the later restrictive stage changes to the solid phase diffusion. The pellet reduction is carried out according to the iron oxide From high to low order, the kinetic analysis using the unreacted nuclear model is correct.