摘要:
为揭示烧结钛精矿气基还原机理,在CO和N2体积分数分别为30%和70%的还原气氛条件下,开展了烧结钛精矿等温气基还原试验研究,还原温度分别为800、900、1 000℃,对气基还原动力学进行了分析。结果表明:烧结钛精矿中铁氧化物还原度随还原温度和时间增加而增加,整体还原度偏低,还原度接近70%。烧结钛精矿在800~1 000℃气基还原大部分时间内(<140 min)受界面化学反应控制,反应活化能为46.97 kJ/mol;反应后期(>140 min)受扩散控制,反应活化能为99.27 kJ/mol。烧结钛精矿碳热还原过程物相转变历程为:Fe2TiO5→Fe2TiO4→FeTiO3。相同还原时间,烧结钛精矿还原样品中金属铁粒尺寸随温度升高从4.46μm增至30.13μm。
关键词:
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钛精矿 /
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烧结 /
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气基还原 /
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动力学 /
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物相转变
Abstract:
In order to deeply understand the gas-based reduction mechanisms of sintered ilmenite concentrate,the isothermal reduction of the sintered ilmenite concentrate was performed under the reduction atmosphere of 30% CO and 70% N2 at 800,900 and 1 000 ℃,respectively.And the reduction kinetics was analyzed.The reduction degree of iron oxides in the sintered ilmenite concentrate increased with increase of the reduction temperature and time,with a relatively low reduction degree of about 70%.At 800～1 000 ℃,the reduction was controlled by interface chemical reaction during most of the reaction period（＜140 min） of the sintered ilmenite concentrate with the activation energy of 46.97 kJ/mol,while it was predominated by diffusion in the last reduction period（＞140 min） with the activation energy of 99.27 kJ/mol.The main phase transformations during the reduction process can be described as follows:Fe2TiO5→Fe2TiO4→FeTiO3.The particle size of metallic iron in the reduced sample increased from 4.46 μm to 30.13 μm with increase of the temperature under the same reduction time.
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