富氧率对钒钛磁铁矿球团还原行为的影响

模拟研究了不同富氧率条件下钛磁铁矿氧化球团的还原过程.通过扫描电镜观察钒钛磁铁矿球团还原过程中的微观结构变化,结合能谱仪研究分析了还原过程中产物的分布变化.结果表明,富氧率的提高对还原度和还原速率提高有明显促进作用.还原过程中钛铁分离伴随着Al元素向高钛矿中迁移富集,最终Al与Ti原子数比为1∶3,Al很可能与钛铁氧化物固溶,形成某种复合化合物并导致球团矿还原难度增加.运用三种不同模型对球团矿还原过程对比分析,发现混合模型可以很好地表征球团矿不同阶段的还原过程.利用混合模型计算得出球团矿还原过程的动力学参数.结果表明,随着富氧率的升高,球团矿还原活化能逐渐降低,从不富氧到富氧79%条件下,活化能由26.5 k J/mol降低到19.68 k J/mol,活化能的降低增加了相同条件下活化分子的数量,提高了反应速率,有利于球团矿在较低还原温度条件下快速反应.

Influence of Oxygen Enrichment Rate on Reduction Behavior of Titanomagnetite Pellets

The reduction process of titanomagnetite concentrate pellets was studied under the simulated condition of blast furnace with different oxygen enrichment rate. The microstructure of the pellets during reduction was observed by scanning electron microscopy. The distribution of different elements in ores was identified by energy dispersive spectrometry. The kinetics of the reduction process was also analyzed. The results show that both the reduction rate and reaction rate increases with the increase of oxygen enrichment rate. Al atoms migrate and get enrichment in high titanium content iron ores， eventually Al and Ti atomic number ratio is 1∶3. Al is likely to solute into titanium iron oxides to form a kind of composite iron compound which results in the restrain of reduction. Three models were used to analyze the reduction process comparatively， and it was shown that the hybrid model was in good agreement with the whole process. The kinetic parameters of pellets reduction process were calculated using the hybrid model. The results exhibit that with the increase of the rate of oxygen enrichment from zero to 79%， the reduction activation energy decreases from 26.5kJ/mol to 19.68kJ/mol.