As has often made global headlines in recent years, rare earth elements are essential for manufacturing, but are often imported through complex processes, creating awkward geopolitical dependencies. One such example is the rare earth metal neodymium, 90 per cent of which is processed in China. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), in collaboration with their project partner TU Bergakademie Freiberg and other stakeholders, are improving recycling methods to recover rare earth elements from old magnets.
The researchers are focusing on neodymium magnets, which the Fraunhofer team counts among the strongest permanent magnets in the world. The institute notes that the combination of neodymium, iron and boron is used in electric vehicles, as well as in wind turbines and electronic products such as speakers, smartphones and hard drives. Global demand for permanent magnets is rising, with estimates suggesting an annual growth rate of up to 8.3 per cent. As the research partners point out, it is very important to recycle hard-to-source rare earth elements like neodymium domestically, but this also involves very complex processes.
Reusing neodymium for new magnets requires a very high level of purity. According to Fraunhofer IKTS, magnets in Europe are currently collected at the end of their first use and sent to China to be reprocessed there.
In the EU project NEO-CYCLE, 23 partners are developing processes to extract valuable raw materials within Europe. Dr Sandra Pavón, head of the Hydrometallurgical Recycling and Raw Material Chemistry group at Fraunhofer IKTS, says, “We aim to recover rare earth elements from electronic waste and use them in high-value products such as green fertilisers and in the production of pharmaceuticals. This will close the materials loop, protect the environment and help reduce global dependence on strategic resources,” she explains.
The upcycling process is possible for various types of magnets. In the NEO-CYCLE project, the focus is on Hard Disk Drives (HDDs), i.e., hard disk drives from discarded computers and laptops that contain neodymium magnets. “We are testing two methods for processing the magnets – solid-state chlorination and electrochemical processes – to determine the most suitable technology,” explains Pavón.
In the solid-state chlorination process, the project partner TU Bergakademie Freiberg adds ammonium chloride instead of conventional hydrochloric acid to the neodymium-boron-iron mixture from the waste and converts it directly into metal chlorides and high-purity ammonia solution in a thermal process. The method is already patented and is being used for fluorescent lamps. Researchers are now testing whether this approach can also be applied to the upcycling of magnets. The results show that metal chlorides can be dissolved much more efficiently from the magnet material, achieving almost complete extraction of the metals with relatively low chemical consumption.
In the second tested method, the researchers introduce pulverised magnet waste into an electrochemical cell. An electrolyte, such as diluted sulphuric acid, serves as the reaction medium for the electrochemical processes. A boron solution is first extracted from the magnets, which is later concentrated. This solution can be used in the chemical and pharmaceutical industries.
The researchers at Fraunhofer IKTS then further separate the products obtained from the two processes, applying their expertise in metal separation and process water treatment. Sandra Pavón and her team use a selective hydrometallurgical process to first extract neodymium and iron. After this, the metal salts can be obtained in their pure form. The separated substances are further upgraded by the project partners and supplied not only to the chemical and pharmaceutical industries but also to sectors such as the hydrogen economy and the fertiliser industry.
The NEO-CYCLE project is funded by the European Union under the Horizon Europe programme. The project runs for four years and is expected to produce a pilot plant, among other things. Sandra Pavón summarises: “The procedure starts with products that have reached the end of their life cycle. At its end, we can supply four different industries with valuable recycled raw materials.”
