Theoretical and experimental study of inclusion removal from molten metal under an alternating electromagnetic force field

One of the emerging technologies for the production of clean metals is electromagnetic filtration. This dissertation describes the work done on the theory of electromagnetic separation in alternating electromagnetic fields together with the experimental results obtained on the removal of silica particles from molten aluminum from an induced current separator.; Analytical expressions have been developed for describing the electric and magnetic fields, and the separation force for a spherical particle in an infinite conducting medium subjected to an alternating magnetic field. It was found that the magnitude and direction of the separation force depends on the ratio of electrical conductivity of the fluid and the sphere as well as the frequency of the applied field. Analytical expressions were also developed for the MHD flow in and around the particle. The solutions revealed two characteristic secondary flows; one is driven by the distortion of the electric current around the particle, while the other is driven by forces resulting from the interaction of the current and the applied magnetic field.; The results of the experimental study on removal of silica particles from aluminum showed complete removal of the particles from the melt, and the rate of inclusion removal was found to depend on the applied magnetic field strength and the particle size. A mathematical model has been developed for describing the rate of inclusion removal from the metal in the induced current separator. The model was found to accurately predict the measured removal rates. The effects of the processing parameters on time for complete removal of inclusions in induced current separators are discussed.