| 摘要 |
<p>PURPOSE:To promote the effective contact of a refining agent with molten steel and to improve the refining effect by supplying stirring gas from a fixed depth from the molten steel surface and adding the refining agent on bubble activating surface. CONSTITUTION:A large diameter immersion tube 2 reducing the pressure is dipped into the molten steel 4 in a ladle 1 and stirring gas 5 is supplied from a porous plug 3 at the bottom part of the ladle 1. Then the stirring gas is supplied from the position being deeper than 0.5 H to the molten steel height H. Further, the bubble activating area (a) formed in the range diameter immersion tube 2 is made to be 40-95% and also, the flux for refining is added onto the molten steel surface in the large diameter immersion tube from a refining agent blowing lance 6. The refining agent grains are sufficiently stirred together with the molten steel in the large diameter immersion tube 2 and floated up and separated to the outer part from the lower end of the immersion tube 2 in order. Therefore, the refining agent for dephosphorization is added in the non-oxidizing condition, and after passing the several time, the deoxidizer is added and successively, even if the refining agent for desulfurization is added, without developing rephosphorization, the sulfurizing reaction can be progressed.</p> |
