Maintaining the working profile of blast furnaces during service

This article looks at the current working profile of blast furnaces at the Krivorozhstal’ combine. The profiles were formed during a period in which the operation of the furnaces was not forced, the supply of raw materials was inconsistent, and furnace output was irregular. The results of studies show a need for closer monitoring of the cooling system and the parameters of the profile of furnaces in the period before a scheduled maintenance. Timely action needs to be taken to eliminate problems in furnace operation caused by the presence of thick slag crusts. It is shown that the variable slag-formation conditions about the furnace circumference are due mainly to factors that affect the smelting operation from below — nonuniform blast delivery and a nonuniform distribution of the blast among the tuyeres, as well as local differences in drainage and the movement of coke in the hearth. These differences depend on the location of the iron notches. It is noted that the aggressiveness of alkalis and zinc in blast-furnace shafts has increased. An efficient furnace profile can be maintained by limiting the entry of aggressive compounds into the furnace and washing its interior to remove such compounds from the circulation loop.