PURPOSE: To prevent a melt loss of a nozzle, and also to attain a sufficient cooling effect, by making cooling gas of controlled quantity flow through a space of a multiple pipe system bottom-blow tuyere provided in a refining vessel.
CONSTITUTION: A concentric multiple pipe system bottom-blow tuyere is provided under the metallic molten bath surface in a refining vessel, and refining gas mainly consisting of oxygen is blown in from an inside pipe 1. Cooling gas is made to flow into a ring-like space between the inside pipe 1 and an outside pipe 2, through a conduit 3 communicating to the cooling gas source. The flow rate of this cooling gas is controlled so as to correspond to the expression I. By this refining method, a nozzle is protected effectively, irrespective of a kind of gas and dimensions of the nozzle.
HOSHIJIMA YOUSUKE
OOGAHIRA KAZUO
