PURPOSE: To obtain ultra-low phosphorus pig iron by using ordinary coke for metallurgy by blowing oxygen-contg. hot air into a furnace from plural tuyeres of two stages, upper and lower, intermittently blowing iron oxide-contg. powder and granular materials into the furnace from the upper tuyere and specifying a furnace top gas temp.
CONSTITUTION: The oxygen-contg. hot air 10 is blown into the coke packed bed type vertical furnace 1 from the plural tuyeres 2, 3 arranged in two stages, upper and lower, in the drum wall part of the furnace 1. The powder and granular materials 5 contg. the iron oxide are blown into the furnace 1 via the upper tuyere 2 and the furnace top gas temp. is kept at ≥700°C, by which the iron oxide is subjected to smelting reduction. At this time, the blowing of the powder and granular materials 5 from the upper tuyere 2 is executed intermittently, by which the melt from the upper part of the furnace is intermittently dropped. The phosphorus formed in the furnace have decreases chances of contact with the melt and the rephosphorization into the molten iron is suppressed. The iron oxide is preferably incorporated at ≥20wt.% into the powder and granular materials. As a result, the extra-low phosphorus pig iron is stably produced. Fuel of 0% phosphorus-component is blown form the lower tuyere 3 into the furnace.
NIKO KIYOSUKE
MARUSHIMA HIROYA
MOMOKAWA HIDEYUKI
KOMAMURA SEI
