Structural Characteristic and Formation Rule of Iron Ore Sinter

Complex sinter structure of iron ore was analyzed and characterized with use of high-power and high-resolusion computerized tomography scanner newly developed. Image analysis system for CT figures was enabled (1) to visualize and observe three dimensional structure of inner portion of sinter, (2) to quantify densification degree of sintered parts, (3) to quantify geometric characteristic from the view point of topology and fractal as well as porosity by size, and (4) to simulate gas flow through pores in sintered body. Distinct relationship between pore size and pore type, that means the difference between open and closed pore, was found. By measuring densification degree distribution of inner sintered body, homogeneity of sintering and ratio of insufficiently sintered portion were evaluated. By analyses of cluster or pore size distribution, structure of iron ore sinter was found to be fractal. Structural changes in cluster and pore size, and densification degree of solid portion, which occur simultaneously during sintering were quantified. These structural changes were found to be ruled by bonding percolation theory. The theory suggests that sintering condition corresponding to the critical point of percolation theory is the best for both gas flow through sintering layer and product yield. Based on the foundings, by checking the fundamentals of experience-based DL process, a new type of feeder, Intensified Sifting Feeder, which ennable to make idealized raw-packed structure was developed, and furthermore reduction of sinter cake load was found to improve permeability with change of pore network.