The invention relates to the technical field of the
steelmaking industry, in particular to a method for
steelmaking and
denitrification of a VD furnace through CO2. The method for
steelmaking and
denitrification of the VD furnace through CO2 is suitable for the VD refinement of 30-350 t of steel ladles. According to the refinement process, bottom blowing of CO2 or CO2-Ar is performed through the steel ladles; different bottom blowing
modes are adopted in all stages, the small-flow
gas mixing bottom blowing is adopted in the
liquid steel composition even-mixing stage, and
liquid steel oxidationis prevented and the vacuumizing speed is increased; the high-flow bottom blowing of pure CO2 is adopted in the high vacuum
decarburization stage,
decarburization of CO2 is promoted, and then deep
denitrification is achieved and
dehydrogenation is enhanced; normal operation of a bottom blowing component is ensured by switching bottom blowing of Ar and high-pressure spraying and blowing in the bottom blowing repetition stage; and in the
liquid steel purifying stage, bottom soft blowing of CO2-Ar
mixed gas is performed, rapid flotation of
nonmetal inclusions is promoted, and at the same time, CO2 gas is the main part of blowing, heat
impact on a bottom blowing
nozzle is reduced, the bottom blowing service life is prolonged, and finally low-cost
smelting of low-
nitrogen steel through the VDfurnace is achieved.