BLAST FURNACE OPERATION METHOD

PURPOSE: A blast furnace operation method is provided to stabilize conditions of a blast furnace and reduce fuel ratio by changing the form of a storage hopper of charging materials used in the blast furnace from funnel flow to mass flow, thereby arbitrarily controlling grain size distribution in a radius direction of the blast furnace. CONSTITUTION: In a blast furnace operation method for manufacturing molten iron by charging a charging material stored in a storage bin into a blast furnace through a top bunker with a surge hopper and a hopper part, the blast furnace operation method comprises the processes of determining critical hopper inclined angles in which a discharging form of the charging materials is changed from funnel flow to mass flow for each principal charging materials by discharging the charging materials through the hopper as changing an inclined angle formed by a horizontal surface and an outer surface of the hopper for charging materials charged into the blast furnace; selecting the largest critical hopper inclined angle in the critical hopper inclined angles for the charging materials; and using a top bunker equipped with the hopper part so that an inclined angle of the hopper part is the same as or more than the above selected largest critical hopper inclined angle as the top bunker, using a surge hopper that is constructed so that an inclined angle is the same as or more than the above obtained critical hopper inclined angles for each of the charging materials as the surge hopper, and storing the charging materials sorted per grain sizes in the storage bin by sorting the charging materials per grain sizes.