机械活化铁氧化物气基还原热力学再探

Further Investigation on Thermodynamics of Gas Based Reduction of Mechanically-activated Iron Oxides

鉴于以往研究中引用了不准确的铁氧化物气基还原反应标准摩尔吉布斯自由能变化表达式,在自行导出的新的表达式基础上,重新探讨了机械力储能对铁氧化物气基还原热力学的影响规律。除纠正了以往研究中4个方面的错误结果外,还发现:FeO本身的气基还原并不受起始温度的限制,但在Fe3 O4气基还原体系中,FeO的还原具有与Fe3O4还原方式转折温度一致的起始温度;由于Fe3O4还原方式的转折温度随Fe3O4储能的增加而线性下降,故当Fe3O4储能时,Fe3O4和FeO的还原将在低于570℃的温度下发生,同时,与该温度对应的平衡CO压力分数或平衡H2压力分数前者下降而后者提高,即CO还原叉形曲线向低温、低CO压力分数方向移动而H2还原叉形曲线向低温、高H2压力分数方向移动。

In view of the fact that the formulas for standard molar Gibbs free energy change of iron oxides reduction which used in our previous research work are not precise,the impact of stored energy on gas-based reduction thermodynamics of iron oxides are further investigated based on new induced formulas.Except for correcting four errors in previous work,it is found out that FeO gas-based reduction itself is not affected by the starting temperature.But in the Fe3 O4 reduction gas-based reduction system,FeO reduction owns the same starting temperature as Fe3 O4 reduction in transition temperature.the temperature for the transition of the Fe3 O4 reduction decreases linearly with the increase of stored energy for Fe3 O4,so the reduction of Fe3 O4 and FeO occurs at the traditional 570 ℃ below when the stored energy for Fe3 O4 is started.Meanwhile,the equilibrium CO（H2） pressure fraction corresponding to the aforementioned transition temperature decreases（increases） with the increase of stored energy for Fe3 O4,that is,CO reduction forked curve moves in the direction of low temperature and low CO pressure fraction while H2 reduction forked curve moves in the direction of low temperature and high H2 pressure fraction.