Toward the responsible use of rare earths throughout their life cycle: results from the CNRS scientific expert review

Often confused with rare metals, rare earths are not rare, and are included among critical metals, without entirely overlapping with them. Rare earths have a wide range of uses, as well as strategic considerations. They are present in numerous miniaturized electronic devices, required for medical imaging and industrial tools that produce a large variety of products, and also represent a key link in the energy transition. China controls 90% of rare-earth refining capacity today, while France has no deposits in its subsoil that are usable in the short term. The collective expert review focused on systematically analysing the scientific literature, setting out from their uses and exploring their responsible use as a potential pillar of supply security policy. This approach breaks out into three aspects: 

• reducing the use of rare earths by replacing them in materials, or via the more moderate use of products containing them; 

• recycling them via “urban mining2 ”;

• and extracting differently by using more environmentally-friendly processes, alternative supply sources, and giving greater consideration to the social aspect of extraction.

Reducing the use of rare earths

Rare-earth extraction processes and waste represent a proven risk for the environment, especially in highly contaminated areas such as mining or transformation sites. Extraction and transformation therefore lead to intense social tension locally, notably due to health and environmental risks. 

There are multiple levers for reducing rare-earth consumption. They include replacing rare earths in materials with other less critical elements, improving the efficiency of the devices that use them, and adopting an approach emphasising moderate use. The latter can, for example, be in keeping with the functionality economy, which prioritizes the use rather than the possession of shared equipment, with a view to reducing raw material demand, all while maintaining the expected service. 

The results of the collective scientific expertise underscore the potential of reduced rare earth use in materials and devices. With respect to permanent magnets, the literature shows that certain processes reduce the quantity of some critical rare earths, whose supply in France and Europe is especially under pressure. Using magnets with no rare earths would require increasing their mass four or five times in order to preserve the same performance. Finally, with regard to the machines using these materials, a well-documented avenue for reduction involves the arrangement of permanent magnets in the mobile part of the motor, and their combination with magnets that do not have rare earths, or that use technologies that do not use magnets.

European regulations for raw materials, which include rare earths, prioritise the strategic security of European industries in connection with levers for moderation. Multiple research efforts have called for a greater role for moderation-based aspects—already present in French and European legislation—within regulations pertaining to critical raw materials, with the circular economy directly contributing to supply security. The creation of a European preference in public markets is also addressed by the literature.

Recycling rare earths

Recycling is a more responsible alternative to the production of rare earths, yet its rate is stagnant globally, with less than 1% of rare earths being recycled. Material life cycle and flow analyses nevertheless show that recycling processes have a smaller carbon footprint than primary extraction. Innovative pre-treatment technologies and metallurgical processes–in addition to the development of short recycling loops–significantly reduce environmental impact, and offer high recovery yields. With its demonstrated technical feasibility, recycling has considerable potential, while usage waste represents a credible and more responsible secondary resource. 

The quantity of rare earths contained in permanent magnets (electrical vehicle motors, offshore wind turbines, electronic waste, etc.) produced in 2020 would represent one quarter of rare-earth mining production for that same year. However, recycling’s potential depends on the concentration of rare earths in materials, as well as the number of objects that must be collected in order to recover them. For instance, 2,000,000 telephones must be collected to recover enough rare earths for a single offshore wind turbine. Collecting them represents a logistical and economic constraint. While law relating to the circular economy and waste management applies to the recycling of products containing rare earths, no legislation specifically requires mentioning that the latter are contained in products, or indicates the specific actions that must be taken regarding their recycling. While the literature shows that public action plays a decisive role in structuring a market for recycling, the legal framework and policy incentives do not yet allow for a stable sector.
 

Extracting rare earths differently

While France possesses marine mineral resources that could represent a rare-earth supply source, major uncertainty remains as to their quantification, economic profitability, and technical challenges. Most especially, the scope of damage would be such that it is impossible to determine whether the seabed would return to equilibrium after its exploitation. Mining and industrial waste are estimated as having the greatest potential as rare-earth sources in France and Europe. While rare-earth concentrations are often lower than those in primary deposits, considerable volumes of such stocks make them interesting potential sources for producing rare earths, especially via the zero-waste approaches described in the literature. For example, the quantity of rare earths contained in the residue from alumina extraction (from bauxite or red mud) or in coal ash (from coal-fired power plants) produced in 2020 is on the same order of magnitude as the global production extracted from mines that same year. However, the data available on these stocks and their properties remain limited. More innovative and environmentally-friendly extractive processes, such as integrating bioprocesses using micro-organisms or plants, are being studied and developed in laboratories.

The scientific expert review also addresses changes to mining law. The literature identified the framework for social and environmental responsibility on the part of mining enterprises as being too lax. It nonetheless emphasizes that French and European law is evolving towards stronger requirements with respect to the “duty of vigilance,” which in concrete terms imposes more responsible extraction of ore on enterprises throughout the value chain, including in third countries. In addition, there are regulatory frameworks requiring enterprises to disclose their environmental and social impact,  which could take the form of technological tools that provide public data. With regard to the social acceptability of mines, the literature points out that contestation emerges in the absence of a preceding debate on the very opportunity of developing new mines. Such contestation cannot be resolved simply through educational or compensatory approaches for the affected local populations.

To consult the synthesis online, click here

Reference :

Towards responsible use of rare earths throughout their life cycle: what are the future prospects in terms of sobriety, recycling and production methods? Synthesis of the Collective Scientific Expert Review. CNRS. 2025.
 

Chief scientists :

Pascale Ricard, CNRS ; Clément Levard, CNRS ; Romain Garcier, ENS de Lyon, on en expert mission for the CNRS.

In addition to the three chief scientists, the main experts who contributed to this work are: Kevin Bernot, Bénédicte Cenki-Tok, Marie Forget, Olga Fuentes, Laure Giamberini, Emilie Janots, Brice Laurent, Gilles Lhuilier, Frédéric Mazaleyrat, Stéphane Pellet-Rostaing, Guido Sonnemann, Eric Van Hullebusch, Fanny Verrax and Alexandre Violle. 

• 2“Urban mining” represents the waste from electronic devices, offshore wind turbines, etc. They are central to industrial strategies. Their recognition as a national sovereignty issue raises the question of whether they can serve as the basis for a large-scale circular economy.