材料期刊网

将球团矿分别在900℃恒温和升温试验条件下还原，研究了球团矿的还原膨胀行为；分析了2种温度条件下球团膨胀机理；对比了2种条件下的试验结果，观察分析了还原后球团的外观和微观组织形貌，得到了导致2种温度条件下球团膨胀差异的原因。研究结果表明：恒温还原球团的最大膨胀值为18.3%，升温还原时为8.3%，恒温还原球团的膨胀行为更加明显；裂纹和气孔的形成以及金属铁的析出形态差异是造成膨胀差异的主要原因。由此得出，为了得到与实际生产相近的还原膨胀行为，球团矿应该在升温条件或模拟的生产条件下进行还原试验。

Experiments were conducted to study the swelling behavior of iron ore pellets in gas-based direct reduction process under two temperature conditions,that are the temperature-rising condition and the 900℃isothermal condition. The two experimental results and the swelling mechanism were analyzed. Also,the difference of swelling behavior be-tween the two reduction conditions was analyzed based on images of appearance and microstructure of the pellets after re-duction. The results showed that the isothermal reduction led to higher reduction swelling index(RSI) compared with the temperature-rise reduction,with the RSI respectively 18.3%and 8.3%. The appearance and microstructure of the pellets after reduction showed that the more the cracks and pores,the higher the RSI,which was also one of reasons for the high-er RSI in the isothermal reduction. In addition,the crystallization of metallic iron was another important reason for the higher RSI. Therefore,to obtain the experiment result of the swelling behavior closing to the actual production process, the experiment should be conducted in the temperature-rising condition or simulated condition.