Magnetohydrostatic separation
Magnetohydrostatic separation (also magnetohydrostatic separation , magnetic leviation ) is a mechanical process for sorting non-magnetic particles, especially metals or minerals (ores), which is based on their different densities .
A ferrofluid ( magnetic fluid) is introduced into an inhomogeneous magnetic field that forms between two magnetic pole pieces; the strength of the magnetic field increases downwards. As a result, the ferrofluid experiences a downward force that acts in addition to gravity. This increases the buoyancy on non-magnetic bodies floating in it. If you change the strength of the magnetic field, the lift force changes; this can therefore be adapted to the density of the materials to be separated. The particles are then separated by the sink-swim process ; H. Lower density particles can be removed from the surface, higher density particles sink to the bottom. Magnetohydrostatic separation processes can be set to a certain (constant) density, or the magnetic field can be slowly increased with an electromagnet so that bodies of ever greater density come to the surface and are skimmed off one after the other.
The magnetohydrostatic separation process is used for high density materials when there are no suitable liquids of sufficient density in which such materials float.
literature
- Y. Zimmels, Y. Tuval, IJ Lin, Principles of high-gradient magnetogravimetric separation, IEEE Transactions on Magnetics, Volume 13, pp. 1045-1052 (1977).