The European Union has set itself the goal of achieving climate neutrality by 2050, a milestone that depends on the continent's ability to develop and implement clean energy and mobility solutions in a way that is both economically viable and environmentally sustainable. The amount of critical raw materials (CRM) needed to facilitate this energy transition is significant. In addition, industrial and household appliances will need to meet stringent energy efficiency standards to support this transition. The most energy-efficient electric motors and generators contain rare earth permanent magnets. While EU companies are world leaders in the production of electric motors, they are completely dependent on imports for the entire value chain of rare earth magnet materials. (Bernd Schaferet.al, A Report of the Rare Earth Magnets and Motors Cluster, Berlin 2021).

Rare earth elements (REEs) are essential components of these permanent magnets, which are critical for many applications that are vital to Europe's future. It is well known that REEs from China have been the main source for Europe, that supplies are uncertain, and that the Chinese production chain is generally unsustainable. At the same time, the demand for REEs for the production of new PMs is expected to double in 15 years.

In light of this data, our work focuses on the collection of EOL magnets and the sustainable recycling and reprocessing of PM from sources, concentrating on the most common and readily available source of economically recyclable electric motors: domestic appliances. We are developing new dismantling and recovery processes for PM on high-availability scrap and reprocessing lines. In HPMS (Hydrogen Processing of Magnetic Scrap)^1,2 we use an already established method of hydrogenation followed by grinding, degassing, and coating of sensitive powders. The HDDR (Hydrogenation-Disproportionation-Desorption-Regeneration)³ process has been implemented to simplify and minimize the steps in the recycling process.

Initial, ongoing pilot trials for the production of sintered and bonded magnets from recycled magnets confirm the waste-free, economic processing and future independence from unstable REE sources. For the production of sintered magnets, a new sustainable process of rapid consolidation is used, while for bonded magnets the most sensitive part to protect the reactive powders is the coating with a few monolayers of chemically bound coating precursor. In addition to magnetic measurements, various analytical techniques (SEM, HRTEM, XPS) are used to characterize the powders obtained by HPMS and HDDR processes, as well as the final magnets.

*This work is part of the “INSPIRES” project financed by EIT RawMaterials, Proposal Number 20090 (project website: https://eitrawmaterials.eu/project/inspires/).

In this study, we explore the challenge of creating anisotropic permanent magnets through the process of additive manufacturing, specifically using material extrusion (MEX). Typically, the production of anisotropic magnets requires the application of an external magnetic field, with the most cost-effective approach being the utilization of permanent magnets in a specific orientation to align the particles. However, when employing a filament-based 3D printer or material extruder, generating an adequate magnetic field presents certain difficulties. The simplest method involves printing directly atop a permanent magnet, as shown in previous studies. [1] However, this approach restricts the magnet's height due to the diminishing magnetic field with distance, eventually leading to a point where particle orientation ceases. Contrary to predictions, our observations revealed that the printed magnet not only sustains but also extends the magnetic field of the underlying permanent magnet. This results in a greater degree of anisotropy at distances further from the magnetic field source than initially anticipated. This discovery opens up new possibilities for more intricate designs, circumventing the limitations imposed by space constraints for permanent magnet placement by leveraging the magnetic field extension provided by the previously printed magnet.