CONVERTER REFINING METHOD

摘要

PURPOSE:To suppress preferential oxidation of Si and to extend the life of a tuyere for which a double-layered pipe is used by operating a converter at the prescribed rate of dilution by an inert gas of O2 passing through the inside pipe of the tuyere which is increased to the rate higher than in a stationary state while Si exists at industrial purity in the bath. CONSTITUTION:The impurities in molten iron are usually oxidized in order of Si and C when the molten iron is oxidation-refined. Si is particularly preferentially oxidized and the oxidation of C is suppressed during this time in the initial period of refining particularly with such a converter as a top and bottom blown converter and a bottom blown converter having large stirring power. The rate of dilution of O2 to be blown through the inside pipe of a double-layered pipe tuyere is increased to the rate higher than in an ordinary condition and the converter is operated at 40-70% rate of dilution in the so-called desiliconization period in the above-mentioned period when a large quantity of heat is generated. As a result, the generation of heat by combustion of Si in the desiliconization period and the corrosion of the slag coating layer by SiO2 are decreased and the rate of eroding the tuyere is retarded.