Magnetohydrodynamic Separation in Metal

Casting with Superconducting Coils

In cooperation with the Lucchini Research Laboratories,
Lucchini Group C.R.S., (Dr. P. Folgarait)

·       In metal processing applications the separation of small nonmetallic inclusions from molten metals is a problem of primary interest.

·       Usually, a metallic melt contains a large number of small solid inclusions (10-100 mm). For example, a typical aluminum melt contains 500-10 000 particles/kg of small particles of oxides (AlO, MgAlO), and carbides (SiC, AlC).

·       Inclusions in alloys reduce mechanical properties (workability), are detrimental to surface finish, increase porosity, and increase corrosion.

·       Conventional electromagnetic separation methods in metal casting are:

1) separation by an electromagnetic induction coil;

2) separation by a travelling magnetic field;

3) separation with superimposed current and superimposed magnetic field.

·       The use of low-intensity magnetic fields and currents are not efficient for two reasons. The first reason is a low Lorentz force density that is insufficient to separate inclusions less than or equal to 50 mm in size. The second is a poor power efficiency with respect to the concomitant Joule’s heating of molten metal. The power is primarily consumed to heat the melt instead of separating the inclusions.

·       We experimentally analyzed the magnetohydrodynamic separation with an externally injected electric current.