微纳米氧化铁粉低温还原特性的研究

研究了低温还原微纳米氧化铁粉的还原特性与机理。用高能球磨法获得的微纳米氧化铁粉在280～400 ℃内用氢气还原，并测定还原后粉末中氧、计算氧化铁粉末的还原率，通过扫描电子显微镜来观察还原铁粉的形貌；找出了氧化铁粒度、还原温度和还原时间等参数对氧化铁还原率、铁粉粒度和粒度分布、铁粉形貌等的影响。从动力学的角度，探讨了粉末细化对低温氢气还原氧化铁活化能的影响。研究结果指出，微纳米氧化铁粉的还原反应遵循吸附自动催化理论，反应动力学遵循界面化学反应理论，研究获得了反应所对应的反应机制函数和相应的动力学方程。

Research on Reduction Characteristic of Micron nanometerFerric Oxide Powder at Low Temperature

Kinetic of reduction, as well as characteristic and mechanism, of micron nanometer ferric oxide powder at low temperature was investigated. The powder was obtained by high energy milling and then reduced at 280-400℃ with hydrogen. Oxygen in the reduced powder was determined and reduction rate was calculated. Morphology of the reduced powder was analyzed by SEM. Influence of the iron oxide size and reduction temperature and time on reduction rate, reduced powder size and distribution and morphology was found. Influence of reduction activation energy of micron nanometre ferric oxide powder at low temperature was investigated in consideration of kinetic. The analytic results show that the reaction of superfine ferric oxide powder can be explained with the theory of adsorption. The process of the reaction is under co control between interfacial chemical reaction and gas inner diffusion. The apparent activation energies are assessed. After analysis of the relations between reduction temperature and reduction rate, the reaction mechanism and dynamic equation of reduction reaction of ferric oxide powder with hydrogen are found out.