METHOD OF BLOWING-DOWN OF BLAST FURNACE WITH LOWERING STOCK

PROBLEM TO BE SOLVED: To provide a method of blowing-down of a blast furnace with lowering a stock by which a lowering level is decided not by restriction on work but by focusing attention on a cohesive zone.SOLUTION: A method of blowing-down of a blast furnace with lowering a stock is provided in which blowing-down is performed with lowering a stock of material charged in a blast furnace, then a repair work is performed on a furnace wall structure at an intermediate position of a blast furnace shaft part and thereafter, a start-up blast is performed. In the method, a distance from a stock line to a top of a curve Ca on the upper surface of a cohesive zone is represented by La, a column having a radius of 0.4×Ra (=Rb) from a furnace center with respect to a radius Ra of a throat of the blast furnace is assumed, a distance from the stock line to an intersection point between the column having the radius of Rb and a curve Cb on the lower surface of the cohesive zone is represented by Lc, and in this case, a lowering stock level Lt is set to the Lc or higher when a level Ls of a repairing work position in the furnace wall structure is La≤Ls