中文摘要：

研究预还原球团在微波场中的升温特性,考察预还原球团微波加热中对直接还原的影响,分析铁氧化物煤基微波加热的还原行为。研究结果表明：预还原程度越高,球团中的Fe3O4含量逐渐减少,浮氏体和金属铁含量逐渐增多,对微波的吸收性能逐渐减弱,但是仍然具有较好的吸波能力。预还原球团金属化率越高,得到的海绵铁金属化率越高,在预还原球团金属化率为42.85%（质量分数）,温度为1 000℃,还原时间为48 min,碳氧质量比为1.75：1时,海绵铁金属化率达到97.29%。随着还原反应的进行,铁氧化物的成分不断改变,金属铁颗粒呈星点状分布于浮氏体之间,但并不会形成致密金属壳,为还原反应中的气体交换创造良好的动力学条件。

英文摘要：

The temperature rising behavior of pre-reduced pellets was studied,and the effects of the reductive degree on the behaviors of direct reduction and the reduction behavior of the iron oxides by microwave heating were investigated.The results show that,the higher lever of the pre-reduced pellet,the less content of the Fe3O4.And then,the contents of wustite and Fe increase gradually.Meanwhile microwave-absorbed characteristics tapers off which still has some absorbing ability.The higher degree of the pre-reduced pellet,the higher the sponge iron metallization is.The mass ratio of C to O is 1.75：1,reduction time is 48 min,the degree of the pre-reduced pellet is 42.85%,and the sponge iron metallization is 97.29% at 1 000 ℃.With the reaction of the direct reduction,the content of iron oxides changes.Iron granules disperse around the austenitic instead of formation of dense metal shell,which will create favorable conditions during the gas exchange and improve kinetics conditions.