OPERATING METHOD FOR TOP AND BOTTOM BLOWN CONVERTER

PURPOSE:To prevent the deterioration of a bottom blowing nozzle and to improve the service life thereof by embedding plural pieces of small-diameter metallic pipe nozzles into refractories in the longitudinal direction of the converter base, mounting a refractory nozzle and blowing uniformly gaseous CO2 via a hermetic wind box to the nozzle. CONSTITUTION:Plural pieces of the small-diameter metallic single pipe nozzle 11 are embedded into the refractories 12 in the longitudinal direction thereof to constitute the bottom blowing nozzle 10. The bottom blowing nozzle 10 is fixed and held to the converter bottom and the hermetic wind box 13 having a function as a gas header is provided to the bottom thereof. The nozzle is connected to a gas supplying pipe 15. The gaseous O2 is blown from a top blowing lance 30 upon starting of blowing with the above-mentioned constitution and the gaseous CO2 is blown from the bottom blowing nozzle 10. A stable mushroom is formed if the pressures of the gaseous CO2 to the respective single pipe nozzles 11 are made uniform and if the gaseous CO2 is blown by increasing the linear flow rate thereof at the nozzle outlets. The service life of the bottom blowing nozzle 10 is thus improved.