Electromagnetically modified filtration of aluminum melts - Part I: Electromagnetic theory and 30 PPI ceramic foam filter experimental results

Abstract

In the present work, laboratory-scale continuous filtration tests of liquid A356 aluminum alloy have been performed. The tests were conducted using standard 30 PPI (pores per inch) ceramic foam filters combined with magnetic flux densities (~0.1 and 0.2 T), produced using two different induction coils operated at 50 Hz AC. A reference filtration test was also carried out under gravity conditions, i.e., without an applied magnetic field. The obtained results clearly prove that the magnetic field has a significant affect on the distribution of SiC particles. The influence of the electromagnetic Lorentz forces and induced bulk metal flow on the obtained filtration efficiencies and on the wetting behavior of the filter media by liquid aluminum is discussed. The magnitudes of the Lorentz forces produced by the induction coils are quantified based on analytical and COMSOL 4.2® finite element modeling. © 2013 The Minerals, Metals & Materials Society and ASM International.