Study of electromagnetic separation of nonmetallic inclusions from aluminum melt

Several methods using the concept of electromagnetic separation of nonmetallic inclusions from an aluminum melt were analytically studied and compared in this article. The migration rate of inclusion particles for each method by exerting different types of electromagnetic field, viz. DC electric field with steady magnetic field, AC magnetic field, and AC electric field, was calculated and compared with the gravity settling velocity. Effects of various operating parameters, such as the imposing time of electromagnetic field, the radius of circular pipe, and the magnitude of electromagnetic force, on inclusion removal efficiency were analyzed and illustrated for each case. It was found that the removal efficiency increases with the increase of imposing time and decreases dramatically with the increase of pipe radius, especially for the AC electric field method. As far as the removal of small inclusions is concerned, the AC magnetic field method is the most favorable one because it has the least dependence of removal efficiency upon the particle size. However, high frequency is needed in order to get the optimum results, and the best values of a/delta are in the range of 2 to 3.