Segregation behavior for fine particles of sintered ores and coke supplied at the top of a two dimensional cold model of blast furnace

Abstract

The segregation and accumulation behavior for the fines of sintered ore and coke was investigated experimentally with a two-dimensional cold model of blast furnace, charging the fines at the top of the equipment together with coarse particles. The fine particle was 0.5mm in diameter and alumina sphere, 2.6mm in diameter, was used as a coarse material. The following elemental motions govern the fines behavior. (1) The fines fall down through the space between the coarse particles. This permeation is due to the continuous change of the packing structure of the coarse particle bed during the descending motion and the fluidization of the fines. (2) The fines are blown up by the gas flow through the space between the coarse particles. In the peripheral charging method for the fines of sintered ore, there is little fines accumulation in the central part of the shaft and the permeation of fines going ahead of the coarse particles is very quick near the walls. This charging method is effective to secure the central stream of gas. In the horizontal uniform and center charges, the fines accumulation increases in the central part of the shaft and deadman surface. In the case of the fine coke of low density, a critical velocity over which the fines begin to move upward by elutriation is successfully estimated on the basis of the regular cubic arrangement of equal spheres. In the horizontal uniform charge, the bridging over between the walls appears when the accumulated fines layer grows to a certain critical thickness with repeating fines charge. © 2005 ISIJ.