6533b830fe1ef96bd1297882

RESEARCH PRODUCT

Développement d'un procédé électrochimique pour le recyclage du néodyme à partir de déchets électroniques

Mickaël Mery

subject

Electronic scraps[CHIM.MATE] Chemical Sciences/Material chemistryPermanent magnetsÉlectrochimieNéodyme[CHIM.MATE]Chemical Sciences/Material chemistryDéchets électroniquesNeodyniumMolten saltsAimant permanentsElectrochemistryRecyclingRecyclageSels fondus

description

Neodymium belongs to the lanthanide’s serie of the period system and is the key component of the permanent magnets Nd2Fe14B which are implemented in electronic devices and “green” technologies like wind turbines or electric cars and bicycles. Nowadays, only one percent of the neodymium in electronic scraps is recycled. Due to the geopolitical considerations and a strong increase of the use of permanent magnets, there is an impoverishment of the raw material resources leading to an instable market.Since some decades, few recycling processes have been developed on a lab scale without any upscaling to the industrial scale. The existing processes have several drawbacks like multiple steps to obtain the final desired product. This means that these methods have a long process time or use a large amount of chemical productsThe aim of this research was the development of a pyrochemical process, which could be an alternative to the existing recycling processes in order to extract neodymium from electronic scraps with less steps, a smaller amount of chemical products and a higher recovery rate of the rare neodymium. For this purpose a special reaction chamber has been created which resists to the severe experimental conditions induced by the use of high temperatures and corrosive molten salts. Moreover the electrochemical behaviour of neodymium in different chloride- and fluoride-based molten salts was studied in order to find the most appropriated setup.We could prove that the pyrochemical method could be the solution to recover neodymium from the old permanent magnets under its metallic form in just one single reaction step during an electrolysis.

https://tel.archives-ouvertes.fr/tel-02078774/file/These_MERY_UTBM.pdf