Braunschweig, Düsseldorf – Das Fraunhofer Institut plant ein europäisch gefördertes Forschungsprojekt mit dem Thema „Recycling von Seltenen Erden“. Kernpunkt ist nach dem Sammeln und Aufbereiten der Abfallstoffe die komplette chemische Auflösung der Wertstoffe, das Überführen in sogenannte ionische Flüssigkeiten und die galvanische Abscheidung der Seltenen Erden als Metall. Hierfür suchen das Institut europäische Firmen, die an einer Mitarbeit interessiert sind; bedingt durch das Programm, werden vorzugsweise klein- und mittelständische Unternehmen gesucht.

(Die Beschreibung des Programms erfolgt aufgrund der internationalen Ausrichtung in Englisch.) Together with a competent consortium the Fraunhofer IST plans an EU-funded project in order to develop the basics for the technically and economically meaningful recycling process of rare earth metals (RE) from disused light metal alloys (i. e. scandium in Al) or lanthanum from fluid catalytic cracking (FCC) catalysts.

Export strictly controlled

Rare earth elements have many functional properties and have been widely applied in magnetic, superconducting, optical materials and electronic devices as well as being used in automotive catalysts. Currently the bulk of rare earth elements is produced in China, whose government strictly controls the export of these strategic materials. Most developed countries import almost all required rare earth elements from China, particularly neodymium Nd, which has been employed for producing neodymium–iron–boron (Nd–Fe–B) permanent magnets.

According to appraisals, the market of neodymium will increase by a factor of 3.8 between 2006 and 2030; the market for scandium, which has a technical importance for fuel cells and new Al alloys will increase by a factor of 2.3 within the same period. About 50 percent of rare earth oxides will be used as catalysts in automotive industry and crude oil refining.

RE recycling very uncommon

A recycling process, from an industrial point of view, could be an efficient way to get rare earth elements from scrap, considering the fact that most of the rare earth elements are produced almost exclusively in one particular country (China). However, until now, the recycling of rare earth elements could be stated as being very uncommon, e. g. most of the fluid catalytic cracking catalysts from catalytic cracking processes in German oil refineries were completely used as additives for concrete. Until now there is no interest in recycling rare earth elements from FCC catalysts (mostly Lanthanum), although the FCC catalysts worldwide contain about 20 percent of rare earth elements.

The commercial production of RE metals will be performed by the chemical reduction of RE-fluorides by metallic calcium, which causes a lot of severe ecological problems. Other preparation methods are the high temperature molten salt electrolysis and the electrodeposition using volatile and inflammable organic electrolytes.

Electrodeposition of RE inionic liquids

Based on this process, a new way is the electrodeposition of rare earth metals inionic liquids (IL) as an alternative for the recycling process. ILs seem to be ideal electrolytes due to their low toxicity and little environmental impact as well as their wide electrochemical windows.

Electrodeposition of RE from aqueous systems is completely impossible. As stated in literature, most of lanthanides can be electrodeposited from ionic liquids, such as yttrium, lanthanum, samarium, europium, gadolinium, dysprosium, terbium, thulium and ytterbium.

More information from Dr. Andreas Dietz (Email: andreas.dietz@ist.fraunhofer.de, phone +49 531 2155 646, mobile 0178 2155 011), Fraunhofer IST, Braunschweig; Dr. Essam Moustafa (Email: essam.moustafa@ist.fraunhofer.de), Fraunhofer IST, Braunschweig; Institut für Seltene Erden und Metalle e.V. (Email: info@institutselteneerden.com), Internet: institutselteneerden.com.

Quelle: Pressebox

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