针对包头固阳褐铁矿磁化焙烧过程中含有丰富孔隙结构的特点，采用氮气吸附法在77 K下对－0．074 mm褐铁矿粉进行了吸附⁃脱附等温线测定，研究了其孔径分布、比表面积等孔结构变化，计算得到其脱水矿的体积比表面积为1．152×108 m2／m3。在此基础上，考虑到还原气体浓度、化学反应和孔隙结构变化对褐铁矿颗粒磁化焙烧过程的影响，提出了传热、传质与孔隙变化的耦合动力学模型，以模拟褐铁矿颗粒在773～873 K温度区间下的磁化焙烧过程。通过数值计算得到颗粒在不同温度下的还原度随时间的变化，同时模拟了一氧化碳在颗粒内部的浓度分布变化，颗粒粒度为－74μm，873 K下，CO浓度为10％时，还原度达到1时所需时间为80 s。%In view of the abundant pore structure of Guyang limonite in the process of magnetizing roasting, nitrogen adsorption⁃desorption isotherms of limonite at the size of -0.074 mm were determined at 77 K, with the changes in pore size distribution and specific surface area of the limonite studied, resulting in the calculation of specific surface area per volume for the dehydrated ore at 1.152×108 m2/m3. With the effects of reducing gas concentration, chemical reaction and variation of pore structure on the magnetizing roasting of limonite particles taken into account, a coupling dynamic model for heat transfer, mass transfer and pore structure variations was proposed to simulate the magnetizing roasting process of limonite particle at the temperature of 773~873 K. The variations in the reduction of particles with time at different temperature were obtained by numerical calculation, and variations in the concentration distribution of carbon monoxide in the particle were also simulated. It took 80 s for the limonite particle with particle size of -74 μm at the temperature of 873 K, with CO concentration of 10%, to achieve the reduction degree of 1.
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