| 摘要 |
<p>PROBLEM TO BE SOLVED: To effectively desulfurize molten steel with little quantity of flux without using slag-making agent of fluoride, etc., by injecting desulfurizing flux containing Mg and lime into the molten steel having a specifized oxygen concn. together with carrier gas. SOLUTION: It is desirable that the desulfurizing flux composed of Mg and lime and having 5-30% Mg content and no fluoride injects together with the carrier gas into the molten steel having 10-100 ppm oxygen concn. It is desirable that injecting quantity of the desulfurizing flux is 0.1-1.0 kg/min/ton and the flow rate of the carrier gas is 0.002-0.02 nm3/min/ton. The injection depth of the desulfurizing flux is regulated to >=125 cm to raise the reaction efficiency. Oxygen concn. in the upper space during desulfurizing is regulated to <=2% to restrain the generation of the low grade oxide, and it is controlled that (SiO2+TiO2+MnO+T.Fe+Al2O3) becomes 40-10% and (CaO+MgO)/(SiO2+Al2 O3) becomes 2.5-4.5, in the top slag after desulfurizing, to restrain resulfurization.</p> |
