VERTICAL FURNACE AND METHOD OF OPERATING THE SAME

摘要

A vertical furnace capable of producing pig iron by charging an iron source of high metallization ratio whose average metallization ratio is 95% or higher and a solid fuel containing 70 to 100 mass% of blast furnace coke in layered form or mixed form from the furnace top onto a bed of coke filling an inferior section of the furnace and melting the iron source while sending air through tuyeres of the inferior part of the furnace. The vertical furnace is characterized in that (i) the distance from the lower face of the tuyere of the stage lowest in the direction of the furnace height to the upper face of bottom plate laid on the furnace bottomis 0.7-fold or more of the furnace diameter at the location of the lower face of the tuyere and (ii) as calculated from the heat conductivities and thicknesses of lining refractories respectively applied onto a shaft part, a tuyere periphery, a wall portion on the furnace bottom side and the bottom plate on the furnace bottom, the furnace body heat radiation per the internal volume of furnace height range from the shaft part to the bottom plate on the furnace bottom is 0.15 Mw/m3 or less.