The operation condition of blast furnace in Japan has been currently changed by the following issues ; green house problems, shortage of coke supply and high production derived from rapid growth of Asian countries. From these backgrounds, high productivity and low reducing agent rate operation in blast furnace will be demanded for Japanese steel industries.
In this paper, the roles of coke, which strongly affects on the blast furnace operation, are discussed, and in-furnace phenomena at low reducing agent rate and high productivity conditions are clarified. On the basis of these discussions, the desirable coke properties to attain the above purpose are described. As a result, the increase in coke diameter and strength to keep permeability and the control of coke reactivity are evaluated to be important so as to achieve low reducing agent rate and high productivity operation of blast furnace.