2015 年 55 巻 6 号 p. 1165-1171
A technique for controlling the mixed coke distribution in the ore layer was investigated in order to achieve low RAR operation of the blast furnace. A reduction test under load was performed with various mixed coke ratio distributions in the height direction. As a result, the ore reduction degree with a high mixed coke ratio in the upper part of the ore layer mixed with coke was higher than ore reduction degree with a uniform mixed coke ratio from the upper part to the lower part of the layer. The effect of the charging pattern on the mixed coke distribution in the ore layer mixed with coke was investigated by a scale model experiment. As a result, it was possible to form an ore layer with a high coke ratio in the upper part of the ore layer mixed with coke at the furnace top by controlling the burden shape of the mixed materials stacked in the top bunker. An operating test was carried out at JFE Steel’s Chiba No. 6 blast furnace on the basis of the laboratory test results. Gas utilization improved after this technique was applied.
