Carbon Monoxide Reduction and Accompanying Swelling of Iron Oxide Compacts
Carbon Monoxide Reduction and Accompanying Swelling of Iron Oxide Compacts
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DOI：
10.2355/isijinternational.36.164
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发表时间：
1996-02
影响因子：
1.8
通讯作者：
M. Nasr;A. A. Omar-A.;M. Hessien;A. A. Ei-Geassy-A.
中科院分区：
文献类型：
--
作者：
M. Nasr;A. A. Omar-A.;M. Hessien;A. A. Ei-Geassy-A.
纯Fe_2 O_3压坯在1373 K下焙烧1小时，然后在973- 1373 K下用CO还原。通过失重技术跟踪复位，而通过位移法测量体积变化。通过反射光显微镜检查了烧结和还原压坯的结构，同时通过X射线衍射技术鉴定了不同的相。这些测量与动力学数据进行了关联，以更好地理解气-固反应机理和伴随的溶胀现象。在1173 K下完全还原的压坯的最高溶胀值为176%，而在相同温度下还原90%的压坯的最大溶胀值为224%。在所有的还原温度下，膨胀增加的减少程度增加到90%，其中获得最大的膨胀值，然后由一个小的减少膨胀时，压坯完全减少。过度膨胀归因于形成的金属铁和/或碳化铁中的碳以及它们与氧反应形成CO和/或CO2。提出了铁粒破碎和压坯膨胀的机理，并与还原条件相关联。
Pure Fe2O3 compacts were fired at 1373K for one hour then reduced with CO at 973-1373K. Reduction was followed up by means of weight-loss technique whereas volume change was measured by displacement method. The structure of the fired and reduced compacts was examined by reflected light microscope while the different phases were identified by X-ray diffraction technique. These measurements together with kinetic data were correlated for better understanding the gas-solid reaction mechanisms and the accompanying swelling phenomenon. A highest swelling value of 176% was obtained for compacts completely reduced at 1173K whereas a maximum swelling of 224% was obtained for compacts 90% reduced at the same temperature. At all reduction temperatures swelling increased with the increase in reduction extent up to 90% where a maximum swelling value was obtained followed by a small decrease in swelling when compacts were completely reduced. Excessive swelling was attributed to the carbon in metallic iron and/or iron carbide formed and their reactions with oxygen forming CO and/or CO2. A mechanism of disintegration of iron grains and swelling of the compacts has been proposed and correlated with reduction conditions.