氢气还原氧化铁动力学的非等温热重方法研究

来源期刊：钢铁2009年第2期

论文作者：庞建明 郭培民 赵沛 曹朝真

文章页码：11 - 14

关键词：非等温方法； 氧化铁； 动力学； 热重分析

Key words：nonisothermal method； hematite； kinetics； TGA

摘    要：用非等温热重分析法对氢气还原不同粒度细微氧化铁的动力学进行了研究。研究表明:铁矿粉粒度越小,起始反应温度越低,反应速度越快,反应达到平台期时所对应的还原率越高;平均粒度为3.5 mm的铁矿粉在400℃还原反应开始,700℃左右开始反应加快,达到平台期时的还原率为77%,而平均粒度为2μm的铁矿粉在100℃已经开始反应,350℃反应加快,达到平台期时的还原率为98%,而且在600℃时还原率就达到了100%;铁矿粉粒度从3.5 mm降到2μm后,还原反应的表观活化能从73.3 kJ/mol降低到30.46 kJ/mol;同时通过分析氢气还原氧化铁的反应机理得出,内扩散和界面化学反应均对整个反应过程起限制作用。

Abstract: Kinetics of reduction of hematite by H2 was studied using nonisothermal thermogravimetric method.The finer the particle size of hematite,the lower starting reaction temperature is.The higher reaction speed,the higher reduction rate at the stationary region is.For 3.5 mm iron oxide powder,reduction started at about 400 ℃,and accelerated from about 700 ℃,and the reduction rate at the stationary region was 77%.But for 2 μm iron oxide powder,reduction already started at about 100 ℃,and accelerated from about 350 ℃,and the reduction rate at the stationary region was 98%,and that the percent reduction rate was 100% at 600 ℃.With the particle size of hematite reducing from 3.5 mm to 2 μm,the apparent activation energy of reduction droped to 30.46 kJ/mol from 73.3 kJ/mol: the analysis showed that both inner diffusion and interface chemical reaction play important roles in whole reaction process.