A Study on the Reduction Behavior of FeO by Analyzing Pore Characteristics Using the Labyrinth Coefficient at High Temperature

The effect of extrinsic porosity on the reduction behavior of FeO was evaluated by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and the Brunauer–Emmett–Teller (BET) technique and analyzed using the labyrinth coefficient of FeO. The extrinsic pore exhibited an abnormal effect on reduction behavior in the range of less than 50% reduction degree, despite the increase in apparent porosity. SEM and BET analysis indicated that the abnormal reduction behavior by extrinsic pores at the initial reduction stage was speculated to be due to the characteristic of extrinsic pore that is open only at one end. However, the overall porosity and reduction rate after a 40% reduction revert to the normal relationship. In addition, the experimental results indicated that the abnormal effect of the extrinsic pores in the initial stage was mitigated by an increase in the temperature. The abnormal effect of extrinsic porosity on FeO reduction was mathematically analyzed using the labyrinth coefficient. It can be summarized that not only the number of pores, but also their quality and distribution are important in determining the reduction rate.