At No. 3 blast furnace of Kimitsu Works, a test operation was planned to foresee the lower limit of fuel rate (the target was 430kg/t-Pig) mainly by controlling the softening-melting zone in the furnace. As a result of the operation, the new record of fuel rate 431kg/t-Pig was attained in March, 1975.
Based on the result of the test operation, the technique to lower fuel rate was investigated and the lower limit of fuel rate to be attained in next 10 years (about 400kg/t-Pig) was estimated by use of mathematical model. The technique for attaining this fuel rate is mainly in the improvement of raw material properties.
