粉煤直接还原磷铁矿的非等温动力学模型

Non-isothermal Kinetics Model for Direct Reduction of Phosphorus Iron Ore by Powdered Coal

以粉煤为还原剂,对惠民高磷铁矿进行了直接还原实验,利用热重实验结果,分析了整个过程的化学反应规律,并考虑挥发份及固定碳的还原作用,建立了高磷铁矿直接熔融还原反应过程模型:即褐铁矿脱结晶水-四级反应成核生长模型,赤铁矿的预还原阶段四级反应模型与终还原阶段二级化学反应减速模型。该模型还指出,由于温度的升高引起分子振荡激发,增加反应通道,提高了反应级数及扩散系数。

With powdered coal as reducing agent, the direct-reduction of Huimin high-phosphorus iron ore was examined. The analysis of chemical reaction rule for the whole process was presented based on TGA experiment results. Then, with the reduction reaction of volatile component and fixed carbon taken into consideration, the reaction process model for direct smelting reduction of high-phosphorus iron ore was constructed, consisting of model for removal crystal water in limonite-fourth-order reaction of nucleation and crystal growth, a fourth-order reaction model of hematite at pre-reduction stage and reducing model of second-order chemical reaction at the final reduction stage. It also can be seen from the model that a temperature rise will result in molecular vibration and an increase in reaction channel, thus both reaction order and diffusion coefficient increased.