The effect of initial total oxygen concentration, [mass%O]T0, on the rate of inclusion removal from molten copper has been investigated.
Under the mechanical stirring condition, it is found that the rate constant of inclusion removal, ko, is independent of the rotation speed of stirrer, whereas it is dependent on [mass%O]T0. From the results of microscopic observation of inclusion particles with SEM, size distribution of inclusion particles is obtained. The rate constant, ko, increases with increasing initial value of particle number density and mean radius of inclusion particle. The change in ko with the initial content of inclusion in the metal phase can be interpreted in terms of coagulation of inclusion particles.
Under Ar gas injection stirring condition, ko increases with increasing gas flow rate, while it does not apparently depend on [mass%O] T0. In the case of Ar gas injection stirring condition, the effect of coagulation on the rate of inclusion removal is smaller than that under the mechanical stirring condition. It is considered that the inclusion particles are removed from the melt mainly through adhesion to the gas bubble-metal interface.
