CO还原Fe2O3过程中金属铁析出的微观行为

 通过原位观察和同步热分析的方式，研究气固两相界面还原反应时金属铁析出形态、矿相结构演变过程，明确金属铁的析出形态与显微结构、黏结特性之间的关系。结果表明，CO气氛下Fe2O3还原时金属铁主要以纤维状生成的铁晶须为主，还原速率是决定这种形态差异的主要原因；在Fe2O3→Fe3O4→FeO中只会因晶格转变产生体积大小变化，且伴有裂纹和孔洞的发生，没有铁晶须生成；在FeO→Fe中出现铁晶须形核和生长，且铁晶须是100%的纯金属铁。要避免铁晶须生成，就要在FeO→Fe转变时抑制铁原子的定向迁移。

Micro-Behavior of the Precipitation of Metallic Fe in the Reduction of Fe_2O_3 Under CO Atmosphere

The precipitation morphology of metallic iron and evolution process of mineralogical structure at gas-solid interface during reduction were studied by in situ observation and thermal analysis to identify the relationships between the precipitation morphology of metallic iron and micro-structure, sticking property. Results indicate that metallic iron is mainly formed as iron whisker with fibrous shape in the Fe2O3 reduction under CO atmosphere, and reduction rate is main reason for the difference of this morphology. In the conversion of Fe2O3→Fe3O4→FeO, the volume is changed just due to lattice transformation, also accompanying crack and hole take place, and no iron whiskers form. The nucleation and growth of iron whiskers (100% pure iron) proceed in the conversion of FeO→Fe. Therefore, in order to avoid the formation of iron whiskers, the oriented migration of atom iron should be inhibited in the conversion of FeO→Fe.