An industrial pilot to recycle used rare earth magnets and manufacture new ones

In Grenoble, start-up MagREEsource will launch in September an industrial pilot capable of recycling used rare earth-based magnets and manufacturing new ones. Its ambition is to participate in securing the supply of critical metals in Europe and to transfer the manufacture of magnets to France.

Rare earths, in particular neodymium and dysprosium, are included in the composition of magnets and are listed as critical raw materials for technical and geopolitical reasons. These magnets are present in many objects in our daily lives: motors, generators, pumps, medical equipment, electronics… In Europe, they are almost entirely imported from China, which poses significant autonomy problems. Faced with this situation, startup MagREEsource has developed a technology to recycle used magnets and manufacture new ones. Its ambition is to participate in securing the supply of critical metals in Europe and to re-industrialise the manufacture of magnets in France. Interview with Erick Petit, co-founder and CEO of this Grenoble-based company.

Engineering Techniques: Why is it important to relocate magnet manufacturing?

Erick Petit, co-founder and CEO of MagREEsource. Credit: MagREEsource

Eric Small: Currently, Europe imports more than 95% of its magnets, which are composed of about 70% iron and 30% rare earths (neodymium, dysprosium, praseodymium, etc.). Today, there is a Chinese monopoly not only on the extraction of rare earths, but also on the manufacture of these magnets. For reasons of sovereignty, it is crucial to reallocate this production.

In addition, we are witnessing an explosion in demand linked to the need to decarbonise the economy and to electrify a large number of equipment, all with magnets. For example, between 2020 and 2030, forecasts predict a 12-fold increase in electric car production and a 4.5-fold increase in wind turbines. Magnets are also an issue in certain sensitive sectors such as defense and nuclear submarine manufacturing or Rafales in particular. Faced with this rapidly growing demand, there is a risk of shortages as mining capacities are currently insufficient. It would be possible to open new mines, but it takes several years. In the absence of European production of rare earths, the only solution to achieving sovereignty is to recycle used magnets, which are an abundant resource.

What technologies do you use to recycle them?

Alloys based on rare earths have very specific properties and have the particularity of presenting weak points in the presence of hydrogen. We use a process called hydrogen decrepitation, which consists of injecting this molecule into the grain boundaries to break this alloy and turn this solid element into powder. Its advantage is that each of the powder particles retains the same composition and microstructure as the originals. The patent for this process is public and is even used by the Chinese in their industrial processes.

To optimize the magnetic properties of this powder, we also use technology developed for the Institut Néel, a CNRS laboratory, to absorb the injected hydrogen. This process is patented and we have the exclusive license, but I prefer not to reveal too much, as we are currently developing equipment with the aim of pre-industrializing this technology.

Coarse magnetic powder. Credit: MagREEsource

What types of magnets do you manufacture?

Thanks to a sintering process, we manufacture solid 100% metallic magnets with high magnetic performance. It requires the use of a press and oven and is the most used technique in the design of magnets.

We also make them by injection, mixing magnetic powder with a polymer, which is then injected into a mold. These magnets have lower magnetic performance but allow complex shapes to be designed. For example, they are used in the manufacture of small electric motors, sensors, etc.

Finally, we are developing a third process in-house using a new additive manufacturing technology with the aim of obtaining 100% metallic magnets with high magnetic properties and allowing the creation of complex shapes. It is still in the R&D stage.

What is the main difference between your manufacturing process and those traditionally used?

We operate in a short loop, that is, from recycled powder, we have the advantage of being able to transform it directly into magnets. When these are made from ores extracted from a mine, the manufacturing steps are numerous and lengthy. First there is the chemical route which requires the use of large volumes of acids to transform the ore into rare earth oxide. Then comes the metallurgical route with a reduction phase to obtain the metal, then smelting to design an alloy, from which a magnetic powder is obtained.

What stage of development is your project in?

Today, we have a pilot laboratory capable of recycling used magnets and manufacturing new ones with a production capacity of approximately one ton per year. In September, we will commission an industrial pilot with a capacity of 50 tons with the sale of the magnets produced. We are currently finalizing the regulatory part that takes time, as in addition to hydrogen, magnetic powder has pyrophoric properties(1) . This mini-factory, which will employ 35 people, will not be fully automated and will allow us to continue our R&D work. In 2025, we aim to build a larger plant with a capacity of 500 tons.

_________________________________________________

(1) Which spontaneously ignites in air or emits sparks by slight friction (source: Larousse)

Leave a Comment