PRODUCTION OF LOW SILICON PIG IRON AT THE TIME OF REDUCING PRODUCTION IN BLAST FURNACE

摘要

PROBLEM TO BE SOLVED: To produce a low Si pig iron without rising the Si content in molten iron, at the time of executing the reducing production temporarily reducing iron tapping quantity during the stationary operation in a blast furnace. ;SOLUTION: Blasting quantity blown into the furnace from tuyeres 4 of the blast furnace 1 is kept constant without changing the blasting quantity during the stationary operation, or reversely, by executing increase of the blasting quantity, and also, an operation reducing oxygen quantity in the blasting according to the reducing production ratio of the molten iron. By this method, the blasting quantity blown from the tuyeres 4 is kept to at least a level at the time of the stationary operation. Since the blasting quantity blown into the furnace from the tuyeres 4 in the blast furnace 1 is kept to the same quantity or above of that during the stationary operation even in the case of reducing the production, it is prevented that the depth of raceways formed in the furnace becomes shallow, and dripping speed of molten iron can be kept equally to that during the stationary operation. As a result, the generation of SiO gas transforming zone is restrained and also Si transforming reaction into the molten iron is restrained and the low Si pig iron can be produced.;COPYRIGHT: (C)1997,JPO