HomeEducationDoctorate (PhD & EngD)For current candidatesPhD infoUpcoming public defencesFULLY DIGITAL (UNTIL FURTHER NOTICE) : PhD Defence Jaap Kosse | Superconducting magnets for magnetic density separation - A NbTi based demonstrator

FULLY DIGITAL (UNTIL FURTHER NOTICE) : PhD Defence Jaap Kosse | Superconducting magnets for magnetic density separation - A NbTi based demonstrator

Superconducting magnets for magnetic density separation - A NbTi based demonstrator

Due to the COVID-19 crisis measures the PhD defence of Jaap Kosse will take place online (until further notice).

The PhD defence can be followed by a live stream.

Jaap Kosse is a PhD student in the research group Energy, Materials and Systems (EMS). His supervisors are prof.dr.ir. H.J.M. ter Brake and prof.dr.ir. H.H.J. ten Kate from the Faculty of Science and Technology (TNW).

The presented work concerns the design of a superconducting magnet for use in Magnetic Density Separation (MDS). This magnet is being constructed at the University of Twente and will serve in a demonstrator set-up for the separation of shredded electronic materials.

MDS is a novel separation technology, developed at the University of Delft, that can be used in for example the recycling industry. The technique is based on the combination of a fluid that is strongly attracted by magnetic fields (a ferrofluid) and a magnetic field with a strong gradient in a single direction. When shredded non-magnetic particles are inserted in the fluid bed, they will move towards different stable depths in the fluid that corresponds to their mass density. This means the MDS process can separate multiple densities in one single step, for example different plastics or electronics.

State-of-the-art MDS systems use permanent magnets. Compared to these magnets, superconducting magnets can offer several benefits. Superconductors can generate a stronger magnetic field, increasing the upwards force. This allows the separation of dense particles such as lead and copper. Another advantage that comes with the stronger magnetic field is that a lower concentration of magnetic nanoparticles in the fluid can be used while maintaining a strong upwards force. This reduces operation expenditure, because the ferrofluid is expensive and must be regularly replenished because a fraction of the fluid is lost during post-processing of separated particles.

A second advantage in using superconducting magnets for MDS results from the fact that the separation resolution scales linearly with the pole size of the magnet. This pole size is limited for permanent magnets due to practical considerations. Electromagnets, made out of coils, do not have this limitation, and thus an enhanced separation resolution is possible.

The presented work involves the design and construction of the first superconducting magnet for use in magnetic density separation.