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A method to produce coke in 'lump' form with high strength and reactivity through the addition of a catalyst was investigated in order to improve blast furnace reaction efficiency. The addition of Ca compounds to coal before carbonization was found to considerably increase the reactivity of the coke at a low temperature range in the thermal reserve zone of a blast furnace. Furthermore it was proved that strong, highly reactive 'lump' form coke could be produced by adding a Ca-rich non-caking coal and adjusting the coal blend composition. Based on this fundamental study, the Ca-rich coke was successfully produced in coke ovens on a commercial scale, both at Kimitsu and Muroran works. The use of the Ca-rich coke in the Muroran No. 2 blast furnace was found to cause a decrease in the reducing agent rate by 10 kg/t-p. This technology, producing coke of high reactivity and strength through catalyst addition, is promising as a means of improving the reaction efficiency of a blast furnace.

The 150 year history of the Japanese steel industry dates from the first western blast furnace, which was built by T. Ohashi in 1857. Modern blast furnace operation at integrated steel works in Japan started in 1901 with the first blow-in of Higashida No. 1 blast furnace at Yawata Steel Works. Throughout the prewar and postwar periods, the steel industry has supported the Japanese economy as a key industry which supplies basic materials for social infrastructure and development.After the period of recovery following the destruction caused by World War II, Chiba Works of Kawasaki Steel Corporation (now JFE Steel Corporation) was built and began operation in 1953 as the first integrated steel works in the Keiyo Industrial Region after the war. During Japan's period of high economic growth, many coastal steel works with large blast furnaces having inner volumes of more than 3 000 m 3 and even 5 000 m 3 were built to enable efficient marine transportation of raw materials and steel products. Japanese steel makers introduced and improved the most advanced technologies of the day, which included high pressure equipment, stave cooler systems, bell-less charging systems, etc. As a result, Japanese steel works now lead the world in low reducing agent rate (RAR) operation, energy saving, and long service life of blast furnaces and coke ovens.Following the Oil Crises of the 1970s, the Japanese steel industry changed energy sources from oil to coal and implemented cost-oriented operation design and technology. In 2012, the Japanese steel industry produced approximately 80 million tons of hot metal from 27 blast furnaces, including large-scale furnaces with inner volumes over 5 000 m 3 . During this period, the industry has faced many economic and social challenges, such as the high exchange rate of the yen, oligopoly in the mining industry, global warming, and the surge in iron ore and coal prices driven by the rapid growth of the BRICs. The industry has successfully responded to these challenges and maintained its international competitiveness by developing advanced technologies for pulverized coal injection, expanded use of low cost iron resources, recycling for environmental preservation, and CO2 mitigation.In this paper, the prospects for ironmaking technologies in the coming decades are described by reviewing published papers and looking back on the history of developments in ironmaking during the last 100 years.

To discuss sinter condition for lowering dripping temperature of molten iron and enhancing reducibility, reduction behavior of sinter samples with extensive range of chemical composition was measured with reduction test under load. Basicity was found to have dominant influence on dripping temperature and should be in the range between 1.0 and 1.5. A further decrease in dripping temperature was achieved by decreasing Al 2 O 3 content and increasing MgO content in sinter, which was related with low liquidus temperature, low viscosity and fast smelting-reduction of slag containing low FeO content. In contrast, reducibility and mineralogy of sinter influenced softening-melting behavior as well. Increasing fine pores could improve softening-melting behavior as a result of enhancing reducibility. Finally optimized sinter, containing 1.0-1.5 basicity, low Al 2 O 3 and high MgO content was proposed. This chemical composition of sinter could lower dripping temperature by 80°C with fairly high permeability of sinter layer compared to conventional sinter. Possibility of the further improvement of softening-melting behavior at a constant chemical composition with controlling sinter mineralogy was discussed.KEY WORDS: agglomeration; iron ore sinter; reduction; dripping; softening-melting; porosity; microstructure.* Notification: As the word expressing the same phenomenon is different among past papers, authors defined the temperature at which the first drip takes place as dripping temperature and the temperature at which pressure drop starts to increase as softening-melting temperature in the present study.teristics such as grain size of hematite and distribution of gangue minerals seems to have the influence on reduction behavior via forming microstructure and pore structure during reduction even at a constant chemical composition of sinter. However the information on sinter mineralogy on high-temperature reduction is still limited. 17) In the present paper, reduction tests under load of sinter with extensive range of chemical composition have been performed and optimization of chemical composition, pore structure and microstructure was discussed to attain suitable properties of sinter for the innovative blast furnace. In particular, conditions for low-temperature drip of molten iron has been focused. Experimental Methods Sinter and PelletsSinter samples with different chemical compositions (basicityϭ1.2-2.6, SiO 2 ϭ3.0-6.8 mass%, Al 2 O 3 ϭ1.1-3.2 mass%, MgOϭ0.2-2.5 mass%) were produced by using a pot simulator whose diameter was 30 cm and 60 cm in bed height. Blending conditions of iron ores and fluxes were changes to attain desired chemical compositions. Table 1 shows chemical compositions of iron ores and fluxes used in the present study. Ore A is Brazilian soft hematite ore and Ore B is Brazilian hard hematite ore. Ore C is Australian soft hematite ore. Ore D is Indian soft hematite ore. Ore E and Ore F are Australian Pisolitic limonite ores. Coke content in a raw mixture was adjusted to maintain sufficient value of si...

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