Effect of iron ore reduction on ferro-coke strength with hyper-coal addition

This study investigates the dominant factors affecting the strength of ferro-coke, which is produced by blending iron oxide with coal particles, with the addition of hyper-coal (HPC), to produce a high reactivity and strong coke. A diametral compression test for ferro-coke with and without HPC addition is performed. A three-dimensional ferro-coke model is then developed using micro X-ray computed tomography, and the relative proportions of pore, pore wall, iron, and pore space surrounding the iron particles, termed here "defect", are quantified using this model. Moreover, a stress analysis is performed for the ferro-coke model. The diametral compression tests indicate that the strength of ferro-coke increases with the increasing blending ratio of HPC. The image-based modeling indicates that the wall thickness increases and stress concentration is relaxed with increasing addition of HPC due to enhancement of the adhesiveness of coal particles. On the other hand, the relative proportion of the "defect" is independent of HPC addition. Therefore, ferro-coke strength is found to be determined not by the "defect" around iron oxide but by the wall thickness.