转炉尘泥含碳球团还原动力学研究

Research on Reduction Kinetics of Carbon-bearing Pellets of BOF Dust and Sludge

在1473~1573K的N2保护气氛下,通过还原失重实验研究了转炉尘泥所制含碳球团的还原特性.结果表明,还原得到的金属化球团全铁(TFe)在67%以上,金属化率(ηFe)在72%以上,可以作为高炉冶炼的原料;转炉尘泥所制含碳球团在0~100s时间内,反应分数受温度影响较小,在100s以后,受温度的影响逐渐增大,温度越高其值越大,转炉污泥球团还原反应分数随温度的变化更明显,反应结束时间在500s左右,比转炉细灰球团要早大约100s.含碳球团还原速度可由Mckwan方程所表达,还原速度由界面或局部反应控制.根据Arrhenius方程可以计算得出转炉细灰含碳球团的还原反应活化能为74.64kJ/mol,转炉污泥含碳球团的还原反应活化能为77.48kJ/mol.

Through the weight-loss experiments,the reduction characteristics of carbon-bearing pellets which were made of BOF dust or sludge,were investigated in a nitrogen atmosphere at the temperature range from 1473 K to 1573 K.The results showed that the conversion rate of the pellets made of BOF dust and sludge in 0~100 s affected by temperature was smaller.In response,100 s later the influence of temperature increased gradually.The reaction fraction increased with temperature.The reduction reaction of BOF sludge pellets was more distinctly influenced with the change of temperature,the reaction was at end at 500 s and about 100 s earlier than the pellets of fine ashes.The reduction rate of the pellets,which can be expressed by Mckwan equation,was controlled by the interface or local reaction.The reduction activation energy was calculated with Arrhenius equation.The activation energy of the pellets made of BOF fine ash was about 74.64 kJ/mol,and that of the pellets made of BOF sludge was about 77.48 kJ/mol.The TFe and metallization rate,ηFe,of metalized pellets were more than 67% and 72%,which can be used as the raw material of blast furnace.