Among the elements composing the crust of the earth, iron exists in the largest quantity next to oxygen, silicon, and aluminum. Iron exists as natural ores in the form of oxides, and the estimated amount of ore deposits in the world is approximately 800 billion tons. Typical ores are hematite (Fe2O3) and magnetite (Fe3O4), having theoretical iron contents of 70% and 72%, respectively. The iron content of practical ores is about 65% at maximum, and these ores include 2-6% silica and 1-3% alumina (Al2O3). Representative sources of iron ores are found in mainland China, Brazil, Australia, the former USSR, America, India, Canada, South Africa, and elsewhere. The phosphorus and sulfur contents of ores differ greatly according to their origin. High-grade iron ore is crushed for sizing, producing both fine ore as well as lump ore. To beneficiate low-grade ore, it is first pulverized into finer particles called pulverized ore. Both fine and pulverized ores are then subjected to pre-treatments before they are charged into the BF; that is, the fine ore is processed into sintered ore by sintering, and pulverized ore is processed into pellets by pelletizing. In Japan, the proportions of iron ores charged into the BF are, at present, 15% lump ore, 10% pellets, and 75% sintered ore. Thus, pretreated iron ores represent a large majority of the ore used. In the sintering process, fine ores 2-3mm in diameter are mixed with coke breeze as a fuel. Burnt limestone powder is used as a flux. These materials are charged in an iron box called a pallet before being ignited. Fine ore particles are partially melted and combined by the combustion heat of the coke to form an agglomerate which is then subjected to crushing and screening processes in order to obtain sintered ore 15-30mm in diameter. The Dwight-Lloyd type of sintering machine is mainly used, sintering being conducted continuously by transferring pallets placed on a caterpillar. Pelletizing is a process that involves mixing very finely ground particles of ore of less than 200 mesh with fluxing materials such as limestone and dolomite and then shaping them into balls 10-15mm in diameter by a pelletizer, and hardening the balls by firing with heavy oil and/or coal as a fuel. Cold-bond pellets are also produced by pelletizing, and do not require firing. At present, small-scale equipment for producing cold-bond pellets is in operation mainly to treat the dust collected in steel works. This technology offers great promise for the future in terms of energy-saving and reducing environmental pollution. Compared with sintered ore, pellets have a higher iron- and a lower gang-content, and pelletizing is suitable for treating the very fine ore that will predominate in the future. However, pellets have the disadvantages that more fossil fuel is consumed during pelletizing and it is difficult to control the radial distribution of the thickness of pellets charged in the BF.