复合粘结剂球团和氧化球团直接还原对比研究

对复合粘结剂球团和氧化球团微观结构、还原动力学参数、还原后强度进行了试验研究。研究结果表明: 复合粘结剂球团中矿物颗粒细小, 平均尺寸为59～104 μm², 孔隙率高, 达到54％～56%, 而氧化球团中矿物颗粒粗大, 平均尺寸为1 047 μm², 孔隙率低, 为30%; 当还原温度大于900 ℃时, 复合粘结剂球团可快速还原, 而氧化球团需要大于1 000 ℃; 800～1 000 ℃还原过程中, 复合粘结球团化学反应速率常数k和扩散系数D_e明显大于氧化球团; 还原后, 复合粘结剂球团结构完整, 强度远大于氧化球团。研究结果表明, 在直接还原工艺中, 复合粘结剂球团具有孔隙率高、还原速度快、强度高的优点。

Comparison Study on Direct Reduction of Composite Binder Pellets and Oxidized Pellets

Experimental studies on microstructure, reduction Kinetics parameters and strength after reduction of composite binder pellets and oxidized pellets were carried out. The results showed that the mineral particles in composite binder pellets were fine, the average size was 59～104 μm², the porosity was high and reached 54%～57%, while the mineral particles in oxidized pellets were coarse, the average size was 1 047μm², the porosity was low and was 30%. When the reduction temperature was above  900 ℃, the composite binder pellets can be reduced rapidly, while the temperature needed by oxidized pellets was more than 1 000 ℃. During reduction process at 800～1 000 ℃, the chemical reduction rate constant K and diffusion coefficient D_e of composite binder pellets were significantly larger than that of oxidized pellets. After reduction, the structure of composite binder pellets was complete and the strength was much larger than that of oxidized ones. The results indicated that composite binder pellets have advantages of high porosity, rapid reduction rate and high strength during direct reduction process.