CONTROLLING METHOD FOR RATE OF METALLIZATION OF REDUCED SUBSTANCE IN SUSPENDING LAYER

摘要

PURPOSE:To enable the rates of metallization corresponding to the true specific gravities of the reduced iron drawn out from a reducing furnace by measuring said specific gravities. CONSTITUTION:The true specific gravities of the reduced iron produced by using various reducing gases such as CO, H2, CO+H2, etc. by fluid layers, suspending layers, jet layers, etc. have the relations expressed by linear equation with the rates of metallization at above 70% of the rate of metallization as illustrated. How much will be the true specific gravities by what operating conditions is beforehand empirically obtained. Then, a part of the reduced iron drawn out from the reducing furnace is sampled and the true specific gravity of the reduced iron is measured in 3 to 5 minutes by using an air comparison type specific gravity measuring instrument or the like after quenching in a non-oxidative atmosphere. If the value thus obtained is not the value corresponding to the required rate of metallization, the operating conditions such as the stagnating time in the reducing furnace, the temperature of fluid layers and reducing gas, etc. are so changed that the reduced iron becomes of the required true specific gravity.