不同碳质还原剂还原Fe3O4特性的动力学分析

Kinetic Analysis of FeO Reduction Characteristics with Different Carbonaceous Reducing Agents

利用热重分析仪对不同碳质还原剂还原Fe3O4特性进行了热重分析,在不同的升温速率(10℃/min、15℃/min和20℃/min)及氮气保护气氛下,研究了升温速率对还原过程的影响,采用Cost-Redfern方法研究了由橡胶籽油在1 250℃下裂解碳、无烟煤、碳粉还原Fe3O4动力学,计算了活化能并比较其还原活性.结果表明:从TG分析曲线可以明显地看出还原剂还原Fe3O4过程可以分为三个阶段,并且随着升温速率的增大,还原反应的最大失重速率向低温区偏移,但其升温速率对还原反应的最大失重影响不明显.通过动力学分析,对10种典型的机理函数进行拟合,比较它们的相关系数和偏差,得出Shrinking core方程最符合描述还原反应阶段,其三种还原剂的还原活性依次为裂解碳>无烟煤>碳粉.

An thermogravimetric analysis of the properties of Fe3O4reduced by different carbonaceous reducing agents was completed by the thermogravimetric analyzer. The effect of heating rates on the reduction process was studied at different heating rate(10 ℃/min, 15 ℃/min and 20 ℃/min) and nitrogen atmosphere. The reduction kinetics of Fe3O4 by rubber seed oil at 1 250 ℃ was studied by Cost-Redfern method. The activation energy was calculated and its reduction activity was compared. The results showed that the process of reducing Fe3O4 by the reducing agent could be divided into three stages from the TG analysis curve. As the heating rate increased, the maximum weight loss rate of the reduction reaction shifted to the low temperature region, but the heating rate had no obvious influence on the maximum weight loss of the reduction reaction. Through kinetic analysis, linear fitting was performed on ten typical mechanism functions, and their correlation coefficients and deviations were compared. It is concluded that the Shrinking core equation best fitted the description of the reduction reaction stage, and the reducing activity of the three reducing agents was in order:cracked carbon>anthracite>carbon powder.