METHOD OF DENITROGENATION OF MOLTEN STEEL AND METHOD OF STEEL PRODUCTION Russian patent published in 2025 - IPC C21C7/00 C21C7/76 

FIELD: performing operations.

SUBSTANCE: invention relates to a method of removing nitrogen, comprising loading molten steel into a reaction vessel, such as a ladle, and bringing molten steel into contact with slag, which is further formed on the surface of molten steel, and also relates to a method of producing steel using said method of removing nitrogen. Method is a de-nitration process, in which slag, including CaO and Al₂O₃, is formed at interconnected stages, one of which is made in order to introduce into molten steel Al in form of a substance containing metallic Al, for deoxidation of molten steel and obtaining Al-containing molten steel, and another step is carried out in order to introduce CaO in the form of a substance containing CaO, which is brought into contact with the Al-containing molten steel to remove nitrogen from the molten steel, while molten steel is mixed with specific power ε, making 60–500 W/t, concentration of Al in molten steel, atmospheric pressure in the furnace and composition of slag are controlled in a predetermined range and either condition (A) or condition (B) is selected so that concentration of nitrogen [N]f reaches 35 ppm by weight or lower, where, according to condition (A), during the process of denitration, the concentration of MgO (MgO) in the slag is set below 5.0 wt.%, excluding 0, and, according to condition (B), the concentration of MgO in the slag is in range of 5.0 wt.% to 20.0 wt.%, and during the process of de-nitration, the temperature Tf of the molten steel subjected to de-nitration is increased by 5 °C or more with each increase in concentration of MgO (MgO) in slag by 1.0 wt.% over 5.0 wt.% compared to temperature of molten steel during said denitrogenation process, which is required to reduce concentration of nitrogen in molten steel to a given value when concentration of MgO in slag is 5.0 wt.%.

EFFECT: fast and reliable provision of the range of minimum concentrations of nitrogen without upper gas blowing.

4 cl, 6 dwg, 1 tbl