循环流化床燃烧及还原焙烧铁矿石试验研究

CFB combustion and experimental study on its reductive roasting of iron ore

运用管式炉和小型循环流化床装置,对湖北某鲕状赤铁矿进行了磁化焙烧—弱磁选试验研究。管式炉磁化焙烧结果表明,在还原性气氛中,将粒径分布于74～150μm的铁矿石5 g在670℃恒温焙烧40 min,经水淬、除渣、研磨后,运用湿式磁选管在192 mT磁感应强度下对焙烧矿物进行弱磁选,可将铁品位由原矿的47.45%提至51.78%;而在同样的实验条件下,运用循环流化床局部还原性气氛磁化焙烧100 g铁矿石只需15 min,并获得铁品位53.47%,TFe回收率56.88%的选别指标。因而证明利用循环流化床的局部还原性气氛提质铁矿石不仅是可行的,而且可以有效地提高磁化焙烧效率。

Using the devices of tube furnace and CFB,experiments on roasting-magnetic separation of Hubei oolitic hematite were conducted.The results of magnetic roasting of hematite in tube furnace showed that,after 40 minutes roasting of the iron ore with the size of 74 μm ~ 150 μm and the weight 5 g at the temperature of 670 ℃ in local reducing atmosphere,water quenching,slag removal and grinding were made,and then using wet type magnetic tube the iron ore was separated with the magnetic induction 192 mT,grade of iron ore can be raised from 47.45% to 51.78%.But in the same situation,to finish magnetic roasting of iron ore with the weight of 100g,only 5 minutes were needed in local reducing atmosphere of CFB,in the same time the grade 53.47% and iron recovery rate 56.88 % of iron ore can be obtained.So that the use of circulating fluidized bed to improve the quality of iron ore in local reducing atmosphere was not only feasible,but also can raise the roasting efficiency.