高反応性フェロコークス製造技術の基礎検討

抄録

The development of production and utilization technology of highly reactive coke is significant in order to improve blast furnace reaction efficiency. In this report, some fundamental aspects of highly reactive iron coke produced in a coke oven chamber were investigated. First, the effects of catalytic Fe powder addition to coal before carbonization on coke strength were investigated. The addition of Fe powder decreased coal caking property and hence resultant coke drum index (DI¹⁵⁰₁₅). On the other hand it increased coke reactivity (JIS coke reactivity index and CRI) to a great extent. This means that caking property of blended coals needs to be adjusted higher to produce the iron coke with properstrength and high reactivity. Secondly, it was shown that the iron ore reacts with silica brick at 1200°C in a condition similar to that in a cokeoven chamber. The iron ore and silica reacted to produce fayalite (2FeO·SiO₂) and the brick was damaged. On the other hand, it was proved that the iron ore does not react with silica brick at 1 100°C in the above condition. Based on this fundamental study, the iron coke with proper strength and high reactivity was successfully produced in coke ovens on a commercial scale by adjusting the coal blend composition and the coke oven temperature. Furthermore it was revealed that about 70% of iron in iron ore powder added to coal was reduced to metallic iron during carbonization in coke ovens.