为深入了解氧化球团在微波竖炉中的升温以及煤基直接还原行为,实验采用铁精矿氧化球团作为基础原料,在气体还原剂条件下进行预还原,通过控制还原时间得到不同还原度铁氧化物球团,并从不同还原度铁氧化物球团的结构以及性能出发,研究它们在微波场中的升温性能及其还原变化.电磁性能测试结果表明,球团中的铁及其氧化物在微波场中的升温速度从快到慢依次为:Fe3O4,Fe2O3,Fe,FeO.微波加热还原结果分析及矿相结构观察显示,Fe2O3的深还原时间较长,物相多重转变,造成过程温度和还原气氛跟不上氧化物的还原反应速度；Fe3O4阶段升温速度快,结构松散,有助于进一步的还原,但进入浮士体(FeO的固溶体)阶段后孔隙率降低,升温速度骤降,造成还原的困难；在还原度达到66.90％时,表层以金属铁相为主,孔洞发达,吸波性能强,在气化反应有效进行的条件下,球团将会实现快速还原.%To study the coal-based direct reduction behavior and temperature rising characteristics of oxidized pellets in microwave shaft furnace, this experiment first prepared several groups iron oxide pellets at different reduction degree by control roasting time in condition of gaseous reducing agent from iron concentrate pellets, then based on structure and properties of iron oxide pellets at different reduction degree, a serials of research about temperature rising characteristics and reduction behavior of them were done in microwave field. The electromagnetic properties results show that the rate of temperature rising of iron oxide powder in microwave field from higher to lower rate is: Fe3O4, Fe2O3, Fe, FeO. The reduction results and mineralogical structure of pellets after microwave heating show that Fe2O3 has longer reduction time and several changes of physical phase, and makes the rate of reduction reaction mismatching with temperature and reduction atmosphere; Fe3O4 has a rapid heating rate and loose structure which is helpful to reduction, but while ferrous oxide appears in the pellet, the rate of reduction decreases because the porosity reduced arid temperature rising rate slowed. When reduction degTee reaches 66.90%, the pellet surface metallization has a developed porosity and stronger electromagnetic wave absorbency which has a fast reduction when gasification reaction is carried out effectively.
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