Improvement of Permeability of Sintering Bed by Adding Dry Particles to Granulated Raw Materials

In order to increase the permeability of the sintering bed for sinter ore productivity, RF-MEBIOS (Return Fine - Mosaic Embedding Iron Ore Sintering) process, in which return fine as dry particle is added to granulated raw materials and then they are charged into a sintering machine, is proposed. In this paper, the pot suction tests and the direct shear tests were carried out to confirm the reason of increasing permeability of the sintering bed by addition of dry particle. As a result, it is proven that the increasing of permeability is caused by two major phenomena. One is by increasing the pseudo-particle size at granulation and the other is by decreasing the bulk density of the sintering bed after charging. The former is achieved by higher moisture content in the raw materials at granulation. The latter is achieved by higher friction in the packed bed composed of dry and wet particle compounds. Therefore, the voids are easy to remain in the sintering bed when the materials are charged into the sinter machine. The influence of the dry particle brand on permeability is not so strong, but larger dry particles make the permeability higher. Also, when the wet particles are added after granulation, the permeability decreased at the same moisture content condition of the packed bed.