The rare earth group consists of 17 elements which are chemically very similar. The rare earth elements are used a wide variety of applications including for example catalysis and lighting. However the most valuable use of rare earth elements is in permanent magnets. There are two main compositions of rare earth magnet which are based upon neodymium iron boron (NdFeB) or samarium cobalt (Sm:Co).
Rare earth magnets play a fundamental role in energy generation and utilisation, which is becoming increasingly important as we move towards an electricity based society. They play a vital role in the aerospace, robotics, electronic, wind turbine, medical, military and automotive industries. There are hundreds of magnets required in electric and hybrid cars within key applications such as drive motors, fans, generators, power steering, pumps, seat motors and loudspeakers.
Today very little rare earth material is recycled which is partly due to the technological difficulties in separating magnets from waste streams. For example to remove an NdFeB magnet contained within a computer hard disk drive would require the removal of 8-10 security screws and the magnet is glued in placed and coated in Ni. A great majority of electronic and automotive waste streams are shredded today. On shredding the contained NdFeB magnets break up into a friable magnetised NdFeB powder which then sticks to the ferrous scrap and the shredder itself.
Robotics
Wind Turbines
Motors in Electric Cars
Computer Hard Drives
HPMS offers an extremely efficient method to extract magnets from end of life waste streams as a pure NdFeB alloy powder with a very low environmental footprint. During HPMS, products are exposed to hydrogen at atmospheric pressure and room temperature. The NdFeB magnets break apart and crucially the powder which is generated is demagnetised which makes it easier to extract. The nickel coating peels away from the surface of the magnets and this can be separated using mechanical means. The extracted NdFeB powder is of a purity whereby it can be re-processed into new magnetic materials or rare earth alloys. HyProMag Ltd will be targeting a wide range of end of life applications.
Illustration of the HPMS process applied to the voice coil assembly of a hard disk drive.
Pilot HPMS reactor capable of processing 5kg of NdFeB
