氢气还原铁氧化物反应表观活化能的评估

Assessment of Apparent Activation Energies for Reduction Reactions of Iron Oxides by Hydrogen

搜集并评估了氢气还原铁氧化物反应的表观活化能。分析了反应动力学条件与反应机理和表观活化能的关系。得出：气体内扩散控速和铁离子固态扩散控速时，还原过程的表观活化能分别为８．０～２８．０ ｋＪ／ｍ ｏｌ和＞ ９０ ｋＪ／ｍ ｏｌ；界面化学反应控速时，将Ｆｅ２Ｏ３，Ｆｅ３Ｏ４ 和‘ＦｅＯ’还原为Ｆｅ的表观活化能分别为４０．０～７０．０ ｋＪ／ｍ ｏｌ，５５．０～６５．０ ｋＪ／ｍ ｏｌ和４２．０～５２．０ ｋＪ／ｍ ｏｌ；两个环节混合控速时，表观活化能介于每个环节单独控速的表观活化能范围之间。

The apparent activation energies of reduction reactions of iron oxides by hydrogen are collected and assessed . The relations among the apparent activation energies , kinetic factors and mechanisms of the reactions are analyzed . The apparent activation energies assessed are : 8.0～28.0 kJ/mol and >90.0 kJ/mol for the reduction processes under gas intrinsic diffusion control and solid state iron ion diffusion control respectively; 40.0～70.0 kJ/mol, 55.0～65.0 kJ/mol and 42.0～52.0 kJ/mol for the reductions from Fe 2O 3, Fe 3O 4 and ‘FeO’ to Fe under interfacial chemical reaction control respectively. The ranges of the apparent activation energies of the reactions under mixed control of two steps are between the ranges of the two apparent activation energies if one of the two steps controls the reactions.