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在800~1 100℃范围内、H_2体积分数为99.99%的气氛条件下,采用气基直接还原工艺对贵州鲕状赤铁矿进行了恒温还原研究,使用X射线衍射仪和光学显微镜对还原产物进行了表征,通过阿伦尼乌斯公式计算了还原反应的表观活化能,并采用未反应核模型判断了还原反应的限制性环节。结果表明:当还原温度为1 100℃,还原时间为150min,二元碱度为1.0时,可以获得金属化率为91.15%的直接还原产物,原矿中加入CaO促进了FeAl_2O_4和Fe_2SiO_4的还原,是还原产物金属化率提高的主要原因。动力学结果表明:原矿在900~1 100℃的还原过程中受气体内扩散控制,其表观活化能为18.95kJ/mol,并且在典型气体内扩散范围内。
Under the atmospheric conditions of 800 ~ 1 100 ℃ and H_2 volume fraction of 99.99%, the gas-based direct reduction process was used to carry out isothermal reduction of oolitic hematite in Guizhou. XRD and optical microscope were used to analyze the reduction products The Arrhenius formula was used to calculate the apparent activation energy of the reduction reaction and the unreacted core model was used to determine the limiting part of the reduction reaction. The results showed that when the reduction temperature was 1 100 ℃, the reduction time was 150 min and the binary basicity was 1.0, the direct reduction product with the metalization rate of 91.15% could be obtained. Adding CaO to the ore promoted the reduction of FeAl_2O_4 and Fe_2SiO_4 Reduction of the main reasons for the increase of metallization rate. The kinetic results show that the ore is controlled by gas diffusion during the reduction from 900 ℃ to 1 100 ℃, and its apparent activation energy is 18.95kJ / mol, which is within the range of typical gas diffusion.