NOZZLE FOR REFINING MOLTEN METAL AND BLOWING METHOD OF GAS

摘要

PURPOSE:To decrease the bottom tapping pehnomenon in refractories and to suppress the erosion thereof in a bottom blowing nozzle having plural through- holes by bisecting the through-holes to an outside circumferential part and a central part and forming the through-holes as respectively separate systems. CONSTITUTION:Refractories 10 disposed and embedded with plural through-holes 9 in suitable positions is covered externally with a winding iron plate 6. A pressure box 12 is so provided as to conduct gas to the holes 9 positioned in the central part and a pressure box 13 is provided to conduct gas to the holes 9 positioned in the outside circumferential part. Inert gas such as Ar, N2 or the like is blown from the box 13 and oxidative gas such as CO2 is blown from the box 12 in the case of blowing the gas into the furnace. It is possible to vary the flow rates of the respective gases in this stage and the flow rate of the inert gas is maintained at the velocity of the sound or higher.