The transformation towards the use of climate-friendly technologies is associated with an expansion of wind energy and electric drives. Powerful magnets are an important component of these applications and their required quantities will also increase. At the end of the life cycle FeNdB magnets are a valuable resource that must be preserved to conserve natural resources and to be more independent from China as the main supplier of rare earth metals and magnets.
There are various ways to recycle used magnets. In direct recycling, FeNdB-based recyclate powders are obtained from the used magnets through hydrogen embrittlement and grinding. The recyclate powders are then processed into recycled magnets by sintering again in the desired geometry. In contrast to elementary recycling, no problematic chemicals and little energy are required. Due to the high oxygen affinity of the rare earth metals, some of the rare earth-rich phase, which is essential for high magnetic properties, is lost during recycling and fresh rare earth-rich powder usually has to be added.

In this contribution, different types of magnets are embrittled to obtain recyclate powders for the laboratory recycling process. The quality of the powders and the subsequently produced recycled magnets are assessed with regard to oxide content, microstructures and magnetic properties. The magnetic properties are influenced by the type (Dy-free, Dy-containing) and quantity of rare earth rich additives. For ecological and economic reasons the amount of new material is kept as low as possible.  The influence of the processing parameters on the evolution of the oxides is evaluated. The number of oxide particles and their size distributions are measured by microscopic methods. The oxide chemistry is analyzed with XRD and EDS measurements.