Effect of Ultrafine Powder of Hematite and Magnetite on Granulation Characteristics of Iron Oxide

Effect of ultrafine powder of Hematite and Magnetite on granulation characteristics of iron oxide was investigated by mixing and exterior coating granulation. The results obtained are follows: (1) In the case of Hematite Ore H, particle diameter of granule is increase with increasing the amount of fine powder in both mixing granulation and exterior coating granulation. On the other hand, in the case of Magnetite Ore M, particle diameter of granule is increase with increasing the amount of fine powder in mixing granulation. In the case of exterior coating granulation using Magnetite Ore M, particle diameter of granule is increase with increasing until 20 mass% of added fine powder but particle diameter of granule is decrease when the amount of fine powder added 30 mass%. (2) The particle diameter dependence of wet strength is relatively small in both mixing and exterior coating granulation. Except for 30 mass% of added fine Magnetite ore M in exterior coating granulation, wet strength of granule is not increase even if the amount of added fine Hematite Ore H and Magnetite ore M is increase. Therefore, it is considered that wet strength of granule is determined by adhesion force of liquid bridge. (3) In mixing granulation, the particle diameter dependence of dry strength is relatively small. In the case of exterior coating granulation, dry strength of granule is decrease with increasing the particle diameter of granule. The dry strength of granule made from mixing granulation is larger than that of exterior coating granulation.