流态化还原铁精粉粘结过程试验研究

Experimental Study on Sticking Process During Reduction of Iron Ore Concentrate Fines in Fluidized Bed

采用热态可视化流化床装置研究了铁精粉流态化还原过程,描述了流化床粘结失流过程的一些宏观表现和颗粒的微观变化。研究发现,失流后不同还原剂引起的料层膨胀程度明显不同,例如用H2作还原剂时料层膨胀40%左右,而用CO时膨胀会达到82%,而且颗粒间的粘结强度也与还原剂的种类有关。同时,适当降低还原温度可以延缓失流的发生也得到了验证,而且CO比H2更为明显。微观上发现这些差异皆与不同还原剂引起的铁晶体不同形态有关。

By the use of thermal state visualized fluidized bed,sticking process during reduction of concentrate fines was investigated.The macrography view of fluidized bed and microcosmic changes of particles were described.It is found that different reductants lead to different swelling levels of batch layer.Swelling is about 40% in H2-N2 mixtures,but it rises to 82% in CO-N2 mixtures.In addition,sticking strength between grains relates to the type of reductant.Furthermore,it is proved that the sticking is postponable by lessening aptly temperature of reduction and the effects of CO are more obvious than that of H2.The results of microcosmic studies showed that these differences are connected with iron crystals morphology.