8th International Congress on Science and Technology of Ironmaking - ICSTI 2018

Improved permeability and increased gas utilization have been desired in order to achieve low coke rate operation of blast furnaces. Coke mixed charging in the ore layer is one measure for realizing these improvements. A new charging technique for mixing nut coke in the ore layer at a blast furnace with a center feed type bell-less top was developed and investigated in an experiment with a 1/18.8 scale model of an actual blast furnace at JFE Steel. The discharge pattern of the mixed nut coke discharged from the bell-less top was improved, and the radial distribution of the mixed nut coke ratio at the furnace top after the mixed materials were charged in the blast furnace was also improved by the new charging technique in which nut coke was charged in the determined port of the upper bunker before ore was charged in the upper bunker. The new charging technique was applied to an actual blast furnace at JFE Steel, and improvement of gas permeability and a decrease in coke rate were confirmed.