Modeling of Inclusion Removal in Ladle Refining

Gas injection is widely used in secondary refining processes to homogenize chemical composition and temperature and to remove inclusions. It is an industrial requirement to minimize the size and concentration of inclusions in the product while minimizing production time to save energy and lessen refractory wear. Gas bubbling is effective to increase the cleanliness of steel mainly by two mechanisms. Firstly, gas bubbling creates the buoyant plume that generates the recirculation flow pattern in the ladle which enhances the transport of inclusions to the top surface, and turbulent mixing with the slag layer to remove the inclusions. Secondly, many inclusions collide with the bubbles and are carried quickly to the top surface, owing to the much higher floatation velocity of a gas bubble, relative to an inclusion.