Modelling of oxygen steelmaking
Oxygen steelmaking is currently the dominant technology for producing steel from pig iron. The process is complex because of the presence of multiple phases (liquid metal, slag, gas, etc.), many components and the non-steady state/non-homogenous conditions within the process. Mathematical modelling has been widely used to evaluate the process and improve the process control due to the difficulties in measuring and visualizing the system at high temperatures. A computer based model has been developed that incorporates the bloated droplet theory under dynamic conditions to evaluate the influences of bloated droplet theory on the overall kinetics of the process. The basis of the theory is that when the metal droplets ejected to the slag-metal-gas emulsion, the metal droplets become bloated due to the inability of gas generated from the decarburisation reaction to escape from the surface of liquid metal droplets. The governing equations and the forms of numerical computational solution techniques for these models are explained. The model, in conjunction with the industrial data, suggests that bloated droplet theory provides a good explanation of the decarburization curves. Approximately 60% of the decarburisation takes place via metal droplets in the emulsion phase during the main blow. The advantages and limitations of these models are also critically examined and discussed.