温度对氢气还原铁氧化物过程膨胀性能的影响

Effect of temperature on swelling behavior of ferric oxide during hydrogen reduction process

为探究球团矿还原过程中产生恶性膨胀的问题,研究了温度对H2还原Fe2O3样条过程中膨胀性能的影响,并采用PCY-G膨胀仪进行在线检测,通过对比不同温度条件下还原产物的外观形貌与显微结构,解释还原反应产生膨胀差异的原因。实验结果表明,H2还原气氛下,随着还原温度的升高,800℃下样条膨胀最大,样条的最大膨胀量出现先增加后减小的趋势;还原反应达到最大膨胀量所用时间逐渐缩短。随着还原温度的升高,铁相连接更加紧密,样条内外产生更大应力差,致使900℃条件下的还原反应提前进入铁相收缩的状态。

To explore the malignant swelling during the reduction process of iron ore pellets,the influences of temperature on swelling behavior of ferric oxide specimens reduced by hydrogen were investigated,and the high-temperature PCY-G dilatometer was used to test that online.The appearance and microstructure of the products reduced at different temperatures are compared,explaining the difference in swelling caused by the reduction.The results show that in the atmosphere of hydrogen,with the temperature rising,specimens swell mostly when the reduction temperature is 800℃,the maximum swelling of the specimen increases first and then decreases,and the time taken for the reduction reaction to reach the maximum swelling is gradually shortened.As the reduction temperature increases,the iron phase links more closely,which results in larger stress difference inside and outside the specimen;therefore,the reaction enters the state of shrinkage of iron phase prematurely at 900℃.