CO气氛下CaO、MgO对金属铁析出微观形貌的影响

采用原位观察和同步热分析的方法, 研究了CaO和MgO对氧化铁气基还原过程中金属铁的成核和生长过程的影响。并结合扫描电镜、能谱和红外光谱等分析, 从微观角度揭示矿相组成CaO、MgO对气体还原时气固界面上金属铁析出行为的影响机理。实验结果表明, CaO和MgO通过改变FeO→Fe转变速率来影响金属铁析出形态。其中掺入MgO是通过降低还原速率的方式抑制铁晶须生长, 掺入质量分数达2%即可完全消除铁晶须；而CaO通过加速还原来抑制铁晶须生长, 掺入质量分数达8%时铁晶须消失。

Influences of CaO and MgO on Precipitation Micro-morphology of Metallic iron under CO Atmosphere

The influences of CaO and MgO on the nucleation and growth of metallic iron in gas-based reduction of Fe2O3 were investigated by in-situ observation and simultaneous thermal analysis methods. Moreover, the mechanism of the influence of CaO and MgO on the precipitation behavior of metallic iron at the gas-solid interface in the gas-based reduction was analyzed from the microscopic point by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and Fourier transform infrared spectroscopy(FTIR). The experimental results show CaO and MgO affect the precipitation morphology by changing FeO→Fe conversion rate. Doping MgO inhibited the growth of iron whiskers by decreasing reduction rate. When the doping mass fraction reached 2%, iron whiskers completely disappeared. However, doping CaO inhibited the growth of iron whiskers by accelerating the reduction, which disappeared when the mass fraction reached 8%.