Can a demagnetized neodymium magnet be restored?

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Discussion Overview

The discussion revolves around the possibility of restoring the magnetic properties of a demagnetized neodymium magnet (Nd-Fe-B) after it has been subjected to conditions that turn it paramagnetic, specifically focusing on methods of extraction and re-magnetization.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions whether a demagnetized neodymium magnet can regain its magnetic properties after being demagnetized at a temperature above its Curie temperature, particularly through extraction and electrowinning.
  • Another participant argues that neodymium does not naturally occur as a magnet and suggests that simply extracting neodymium from a demagnetized magnet will not restore its magnetic properties, proposing instead to re-magnetize the magnet at the factory.
  • A different viewpoint suggests that heating the magnet above the Curie point while applying a magnetic field could restore its magnetic properties, noting that it may not be necessary to reach the Curie point if a strong enough magnetic field is applied.
  • Another participant challenges the initial premise by stating that dissolving the magnet would alter its properties, questioning the concept of regaining "ferrous properties" since pure neodymium is not ferromagnetic.
  • This participant also inquires about the purpose of the proposed extraction and re-magnetization process.

Areas of Agreement / Disagreement

Participants express differing views on the methods of restoring magnetic properties and the nature of neodymium itself. There is no consensus on the effectiveness of the proposed methods or the implications of extracting neodymium from a demagnetized magnet.

Contextual Notes

There are unresolved assumptions regarding the properties of neodymium and the effects of various processes on its magnetic characteristics. The discussion does not clarify the specific conditions under which the proposed methods would be effective.

juyoung518
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Can a Neodymium magnet get back it's magnetic properties after being demangnetized?

Say that there is a Neodymium magnet(Nd-Fe-B) that has been demagnetized(turned paramagnetic) at a temperature higher than its curie temperature.

If I extract the demagnetized Neodymium(Nd) from the magnet(Nd-Fe-B) by dissoving the magnet in an acidic solution and Electrowinning(Electro extraction) it, will the extracted Neodymium regain it's ferrous properties?
Thanks in advance.
 
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Neodymium isn't naturally a magnet. What I mean is it doesn't come out of the ground magnetised. You have to turn it into a magnet by putting it into a coil and passing a large current through it. So simply extracting the Neodymium from a demagnetised magnet won't turn it back into a magnet.

There is no need to extract the Neodymium. You just send the demagnetised magnet back to the factory and put it through the magnetising coil again.
 
You don't need to dissolve the magnet. If you heat the magnet above the Curie point (~310C), apply a magnetic field, and slowly cool the magnet, then you should restore the magnetic properties. It might not be necessary to reach the Curie point, if you apply a strong enough magnetic field.
 
If you do this dissolving, the fact that initially the magnet is demagnetized is irrelevant. Ferromagnetism is a property of the crystal. So by dissolving the crystal the properties will change anyway.

And Neodymium is paramagnetic so what do you mean by regaining its "ferrous properties"?
Pure Neodymium is not ferromagnetic, is it?

What is the purpose of all this, by the way?
 

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