Method for denitrifying molten steel

Abstract

Proposed is a technology capable of inexpensively and stably reducing the nitrogen concentration in molten steel within a melting furnace or a refining furnace to a low nitrogen concentration range. Provided is a method for denitrifying molten steel including supplying an oxygen-containing gas and a carbon source carried with a carrier gas to the molten steel charged into a melting furnace or a refining furnace, in which the oxygen-containing gas and the carbon source are simultaneously blown onto the molten steel under a condition that, provided that a triangle ΔXYZ is defined by connecting, in a plan view seen from above, a distal end (point X) of a discharge port of a carbon-source blowpipe; an intersection point (point Y) between an inner wall of the furnace and a line obtained by extending a central axis of a carbon source blowing direction; and a distal end (point Z) of a discharge port of an oxygen-blowing lance, that a point W is positioned on a side XY that is away from the point X by a distance ⅔ a length of the side XY, and that an angle) θ1(°) is an angle ∠XZW, an angle θ2(°) of an oxygen-containing-gas blowing direction that is open toward a Y side with respect to a side ZX passing through the distal end (point Z) of the discharge port of the oxygen-blowing lance in the plan view seen from above is a positive value and is the angle θ1 or less.

Dependencies are inferred from the claim text.