Magnetic separation using high- superconductors

Abstract

A magnetic separator with an iron return circuit that employs a high- superconducting coil has been built on a small scale. This type of separator, using an iron yoke, has been used by the mineral industry for many years and there appears to be an opportunity for the retrofitting of superconducting coils into existing machines to run them much more cheaply and closer to saturation. This paper describes the design requirements of such an apparatus when a high- superconducting coil is used to generate ampère-turns instead of a resistive one, and in particular the necessity to limit the magnetic stray field at the coil below the critical values. The strong anisotropy of the critical current characteristics with respect to the direction of the magnetic field of the present high- tapes imposes the consideration of two load lines, one for the axial field and one for the radial field at the solenoid. From this analysis the radial component, perpendicular to the tape surface and hence in the low direction, determines the upper limit for the operating current at 77 K. The analysis has been carried out using a 3D finite element package to model the apparatus and to calculate magnetic fields in the air gap of the separator and on the coil windings. The performance of the separator has been tested at 77 K.

Effects of filter shapes on the capture efficiency of a superconducting high-gradient magnetic separation system

“…Recently, high-gradient magnetic separation (HGMS) has been researched for the development of highly compact wastewater treatment systems [6][7][8][9][10]. The use of a superconducting magnet enhances the filtration performance of the HGMS system, because the absence of Joule heating losses leads to the facile generation of high magnetic fields.…”

Theory of high gradient attractive magnetic separation of superconducting materials and its experimental verification by YBa2Cu3Oxparticles

“…In high gradient high magnetic field separation of ferromagnetic materials from less magnetic ones [24], a similar principle is implemented, although systems using steel wool [25,26] provide attraction for both χ > 0 and χ < 0 particles. In the present solution, strong χ > 0 matter in the normal state may be filtered by a precolumn.…”