The recycling of permanent magnets is the breakthrough that markets have been waiting for. For some years now, in the vast world of magnets, there has been discussion about what can still be discovered, invented, and explored. In short, it’s all about the future, a word that can drive research and R&D departments, but also one that can be quite frightening.
China’s presence in the European market worries many sectors, not just the one examined here. This is because China currently holds the monopoly on the extraction and production of rare earth magnets. However, the regions affected by this dominant and “bulky” producer could have an impact on the magnet market. In Europe, in fact, there are many entities that have the potential to try to compete with China’s production of certain types of magnets.
The Process of Recycling Permanent Magnets
The possibility of producing magnets from raw materials that do not come from China —more specifically, from “old” magnets —is being discussed detailly. And so, the term that has been dominating Europe’s last decade, “recycling,” is starting to emerge in the magnet world as well.
How can a recycled permanent magnet be created?
What steps need to be taken?
Is it really possible to break free from China’s dominance in the production of permanent magnets?
To answer these questions, we need to make some premises and considerations to avoid falling into useless dreams and dangerous fantasies. As always, data and facts are the only useful starting points for answering our questions. For example, we can refer to the exhibition held on December 3rd and 4th 2024 in Amsterdam, “The Magnetics Show Europe 2024”, which focused on the future of magnets, new technologies, and where pioneering companies in the sector are investing.
As industry experts, it is essential for us to attend such events to stay updated on the recycling of permanent magnets. This allows us to gather the most important data to analyze what could be the new market, in addition to answering the previously posed questions.
During the many conferences held, several interesting topics emerged, such as raw material extraction, tools for magnets control and analysis, and different types of ferromagnetic materials and their production methods. Among the various topics discussed, there were also insights into GBD (Grain Boundary Diffusion) and the production of “second life” magnets. These are all significant topics that deserve a brief review, without delving too much into technical details.
The Crucial Role of GBD in the Recycling of Permanent Magnets
The GBD technique has been around for a few years, but today, more than ever, it is being analyzed by many companies. This process involves achieving structural uniformity in elements such as Dysprosium, which molecularly bonds with the other elements in the magnet. It’s no longer just adding a component to the mixture for the sintering of the finished product; it is a fully studied, analyzed, and, most importantly, controlled process. Moreover, the GBD process offers the great advantage of using a reduced amount of dysprosium compared to the standard process. The result is cost reduction while maintaining the same performances.
Several companies that use this technique have provided data, especially regarding the control that can be applied to this process. This led to the creation of new alloys that are difficult to produce with traditional methods.
Without going into detail, a magnet made with the GBD technique will be produced with less material and, if desired, with much higher Hcj (intrinsic coercivity) values than a one made without this production method. In addition to this improvement, it is important to underline the uniformity of performance that this process offers in every single portion of the magnet, ensuring homogeneity. High and uniform Hcj values make a magnet more resistant to external demagnetizing fields, one of which is temperature.
Sectors such as aerospace, automotive, defense, and their R&D departments rely very much on the high performance that each component of their products must have. In these terms, controlling the operating temperature of an object is crucial. Having a magnet that allows for better, more balanced, and controlled temperature management, combined with the reduced use of dysprosium, is undoubtedly an advantage.
In conclusion, GBD is a huge advantage for those seeking and wanting an innovative solution that perfectly meets the needs of the current market. And GBD is inevitably linked to the next topic: the recycling of permanent magnets and the so-called “second life.”
What Are the Challenges in the Process of Recycling Permanent Magnets?
In theory, creating magnets from the recovery of raw materials of other magnets is a great idea. Let’s briefly look at the difficulties of this process and the solutions some companies have adopted to make this technology more feasible.
Recycling a Used Magnet
Some methods have been examined for the “destruction” of a used magnet. For example, subjecting it to a certain number of Bars of pressure inside a hyperbaric chamber with hydrogen or nitrogen present. This process “breaks down” the magnet into microscopic elements, which, once filtered, crushed, and processed, are almost ready to be sintered again to create a new magnet. The steps are different and quite complex, but the concept is that it is possible to reprocess used magnets to produce new ones.
The Energy Performance of a Recycled Magnet
The second question concerns the magnetic performance the new object might have once re-sintered and magnetized. No one has yet been able to achieve a recycled magnet with the same initial performance, at least in terms of Br (remanence). However, the results are excellent for the required levels, as about 75-80% of the remanence of the original magnet is recovered. The coercive properties of the magnet are harder to recover. This is where GBD comes into play, which, with a controlled and optimized process, allows for much higher Hcj values. So, we have a fusion of two new concepts with the second life of a magnet, with excellent performance, at least concerning Hcj.
Both innovation and future inevitably follow today’s trends. The concepts of “green” and “recycling” have become the new key terms to refer to, also entering the magnet market.
We’ll conclude with a deliberately provocative question to make people reflect, not so much on the application method discussed, but on the willingness to use this technology and its real feasibility in this sector:
A leading company in the automotive market, which demands the best from each of its components, would be willing to purchase and use a recycled component, instead of a new one? Would it be willing to pay more for it, if produced in Europe (currently)? Knowing that some critical performance metrics (Br) might not be at their maximum potential?
At present, we don’t have an answer to this question, as too many factors come into play to give a definitive answer. At the same time, it does make us think about which direction our efforts should take, in terms of future development and the recycling of permanent magnets.
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