| 摘要 |
<p>PURPOSE: To desulfurize to refine molten iron with an excellent so removal efficiency by ejecting desulfurizing agent into the molten iron from a lance and blowing reducing gas at a specific position on the molten iron surface. CONSTITUTION: At the time of pre-desulfurization for refining molten iron previously to the refining of the molten iron tapped from a blast furnace into molten steel by decarburize-refining, the lance is dipped into the molten iron and powdery flux for desulfurization having composition composed of 20wt.% CaF2 and the balance CaO is ejected into the molten iron, and also, the reducing gas having a composition contg. <65% H2 , <43% CH4 and <16% CO is blown onto the molten iron surface from another top-blowing lance. In this case, coke oven gas is used as the reducing gas, and the operation is executed in a condition satisfying d<=0.25H+0.65D, wherein an interval between the tip part of the blowing lance and the molten iron surface is defined as H, a dipping depth of the blowing lance for desulfurizing flux as D and a horizontal interval between both lances as (d) to desulfurize-refine the molten iron in the excellent SOx removal efficiency.</p> |
