| 摘要 |
PROBLEM TO BE SOLVED: To provide a preliminary treatment method of molten iron, in which various kinds of refining agents are blown together with carrier gas to molten iron housed in a treatment vessel from an immersion lance immersed in the molten iron, and the molten iron is subjected to a preliminary treatment of any of desiliconization treatment, dephosphorization treatment and desulfurization treatment, and in which reaction efficiencies of the refining agents blown from the immersion lance is improved as compared with conventional ones.SOLUTION: The preliminary treatment method of molten iron is provided in which refining agents are blown together with carrier gas from the discharge hole 1b of an immersion lance 1 immersed in the molten iron housed in a treatment vessel into the molten iron in a horizontal direction, or in an obliquely upward direction or an obliquely downward direction, and the molten iron is subjected to the preliminary treatment of any of desiliconization treatment, dephosphorization treatment and desulfurization treatment. In the method, a sectional shape with respect to an axial center, of the discharge hole is a flat shape having the maximum length L in a longitudinal direction larger than the maximum length W in a lateral direction. |
