The carbon neutrality continues to require reduction of carbon usage in ironmaking and steelmaking
processes. Specially, it is expected that the hot metal ratio (HMR) in the steelmaking process should
be reduced essentially. Unfortunately, the reduction of the HMR in converter can bring about poor
environment for nitrogen removal from molten Fe. From this situation, nitrogen prediction model has
been developed to understand the fundamental of behaviour of nitrogen and quantitatively interpret
its content changes in the converter process. Thermodynamic and kinetic approaches were
improved based on existing mathematical model and attempted to predict nitrogen content in realtime
by combining process data. In present study, heat supply from the oxidation (mainly carbon and
silicon) and CO evolution in the converter are considered, and scrap melting due to the heat transfer
from the molten Fe to the solid scrap charged in the converter also be considered.