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David Dupont
David Dupont

Powerful magnets are pulling the world in a more sustainable direction

Magnets,

Every child is amazed when he is given a magnet to play with for the first time. Their invisible power to attract metals still captures the imagination and continuously leads to new innovations both in the nanoworld as magnetic nanoparticles and magnetic fluids, but also in the macroworld in the form of MRI scanners, wind mills, superconductors, magnetic levitation trains, magnetic refrigeration or even the CERN particle accelerator.

Magnetic behaviour is observed in materials that contain zones with net orientation of their electron spins in a certain direction. This creates a north and a south pole and invisible magnetic field lines run from one pole to the other. It is easy to visualise this using a bar magnet and iron shavings, as the iron shavings all align with the magnetic field lines. Depending on the material and its electronic properties, it will experience a strong attraction to a magnet or not. Sand, for example, is not attracted by a magnet, while iron certainly is.

Magnets: attracting sustainability

Permanent magnets and electromagnets are crucial in many green and high-tech items including headphones, speakers, hard disk drives, electric motors, wind mills, dynamos and many others.1 A car can contain over different 100 magnets to control all the electronic motors in the car hidden for example in the brakes, speakers, seats, windows, heaters, A/C, engine, adjustable mirrors and rooftops. In an effort to miniaturise all these motors, neodymium-iron-boron magnets (NdFeB) have taken over an important part of the (high-tech) magnet market. These magnets are unmatched in strength, which helps the miniaturization of devices.  They are more expensive though, since they contain large amounts of valuable rare-earth metals.2 Efforts to reduce or replace these critical elements have not yielded conclusive results and, to this day, NdFeB magnets are still the most powerful, widely available magnets on the market. The evolution of green tech is expected to drive a massive increase in the demand for neodymium and dysprosium, two of the most critical rare-earth elements.3 A scarcity  of these rare-earth elements could effectively hinder the further development of green technologies.4,5 Large efforts are therefore being made to recycle these magnets from end-user products like cars and hard disks.6

 

In any case, with a yearly consumption of 700.000 tons of permanent magnets every year, it is fair to say that magnets are here to stay as they have entered  every part of our lives  and will continue to do so.7 Strong and reliable permanent magnets are a crucial part of the future.

 

The levitating train and still, much more to come…

New applications are still emerging like the magnetic levitation trains (Maglev) in Asia, and  many more new developments are bound to  follow in this century – see below.

The attraction power of a magnetic is free,  lasts forever and can be incredibly strong when scaled up. Speeding up elementary particles to the speed of light in CERN, looking at the inside of the brain in an MRI scanner or levitating entire trains while they move at breathtaking speeds across Japan – even today reality shows that magnets can achieve surprising feats.

Besides being important for many applications, magnets are also fun to experiment with. Some effects are so bizarre that even trained scientists cannot help but to be amazed by some of the behaviours exhibited by magnetic materials like ferrofluids or levitating strawberries.

Ferrofluid:


 

 levitating strawberry

 

References

  1. http://www.prnewswire.com/news-releases/permanent-magnets—types-applications-new-developments-industry-structure-and-global-markets-273850501.html
  2. Report on Critical raw materials for the EU; European Commission, DG Enterprise & Industry: Brussels, 2014.
  3. Alonso, E.; Sherman, A. M.; Wallington, T. J.; Everson, M. P.; Field, F. R.; Roth, R.; Kirchain, R. E. Evaluating Rare Earth Element Availability: A Case with Revolutionary Demand from Clean Technologies. Environ. Sci. Technol. 2012, 46, 3406-3414.
  4. http://www.cnet.com/news/rare-earth-metal-recycling-needed-to-power-green-tech/
  5. http://e360.yale.edu/feature/a_scarcity_of_rare_metals_is_hindering_green_technologies/2711/
  6. Binnemans, K.; Jones, P. T.; Blanpain, B.; Van Gerven, T.; Yang, Y.; Walton, A.; Buchert, M. Recycling of rare earths: a critical review. J. Clean. Prod. 2013, 51, 1-22.
  7. Roskill Consulting, Permanent Magnets the Demand for Rare Earths, 2012.

 

Images credits and references