Hirohata No. 1 BF and Kukioka No. 4 BF of Nippon Steel Corporation were blown down in a usual operating state and dissected very cautiously after quenched with water. The conditions in the reducing zone of the furnace shaft are explained in this report.
From these investigations burden distribution, gas flow at the shaft deduced from the burden distribution, changes of burden properties according to the progress of reduction, and the behaviors of Zn, S and alkali materials in the shaft were clarified. Both furnace conditions were carefully compared to the respective operating conditions. The relation between the operating conditions and the changes of burden properties at the shaft were cleared.
Based on the results of dissection, burden testing methods and necessary burden properties are discussed.
