METHOD OF REMOVING NITROGEN FROM MOLTEN STEEL, METHOD OF SIMULTANEOUS REMOVAL OF NITROGEN AND SULFUR FROM MOLTEN STEEL, METHOD OF PRODUCING STEEL Russian patent published in 2024 - IPC C21C7/64 C21C7/76 

FIELD: metallurgy.

SUBSTANCE: invention can be used for removal of nitrogen and sulfur during steel refining. Slag containing CaO and Al₂O₃ is formed on top of molten steel loaded into the tank. Oxygen or oxygen with inert gas is blown from above onto slag; at that, slag and molten steel are in contact with each other to remove nitrogen from molten steel. Concentration of Al in molten steel is maintained at or higher than the value defined by formula (1) in accordance with specific mixing power. Oxygen-containing gas is injected so that the ratio between the thickness L_s0 of the slag and the depth of penetration into the slag L_s, formed as a result of blowing with the oxygen-containing gas, corresponds to L_s/L_s0 ≥ 1, wherein concentration of Al (wt.%) in molten steel = −0.072×ln (specific mixing power (W)/t)) + 0.5822 (1).

EFFECT: invention makes it possible to stably and quickly achieve a low range of nitrogen concentrations; besides, removal of sulfur and nitrogen is performed within the framework of one treatment of steel.

8 cl, 7 dwg, 1 tbl, 4 ex