Value Analysis of Neodymium Content in Shredder Feed: Toward Enabling the Feasibility of Rare Earth Magnet Recycling

Bandara, H. M. Dhammika; Darcy, Julia W.; Apelian, Diran; Emmert, Marion H.

doi:10.1021/es405104k

Cited by 37 publications

(33 citation statements)

References 27 publications

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“…Less than 1% of the REEs were recycled by 2011 [1], and no data have been provided on the development of new large-scale processes. The scarcity of data on the quantity of REE materials from magnets in the waste streams and the fate of the magnets after shredding has handicapped the development of REE recycling processes [5]. One route by which the REEs can be recovered from magnets is hydrometallurgical in nature.…”

Section: Introductionmentioning

confidence: 99%

Characterization and Leaching of Neodymium Magnet Waste and Solvent Extraction of the Rare-Earth Elements Using TODGA

Gergorić

Ekberg

Foreman

et al. 2017

J. Sustain. Metall.

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The rare-earth elements (REEs) are considered as some of the most critical elements in the EU and the USA today. E-scrap, such as end-of-life neodymium magnets, could be a viable secondary source for the recovery of these elements. Neodymium magnets (NdFeB) consist of considerable amounts of Nd, Dy, Pr, and some other REEs, depending on the specific application. Apart from REEs, neodymium magnets are made up of around 60% iron, which can pose a challenge in their recycling. For example, iron can be dissolved along with other elements during leaching or co-extracted during solvent extraction. In this work, extraction of REEs with TODGA (tetraoctyl-diglycolamide) from a real leachate, obtained by neodymium magnet powder dissolution in nitric acid, was studied. The goal was to selectively extract the REEs from other elements in the solution. TODGA was used as the extracting agent due to its selective extraction properties for REEs and other f-block elements. The influence of the diluent on the overall extraction and the selectivity of the extraction was studied in order to determine application feasibility of future processes. To this end, experiments using Solvent 70 (hydrocarbons C11-C14, B0.5 wt% aromatics), hexane, toluene, cyclohexanone and 1-octanol as the diluents were performed. TODGA has shown good selectivity between REEs and other elements in solution under almost all conditions, reaching the highest distribution ratios of REEs in the aliphatic diluents, while the distribution ratios of other non-REEs reach a mere value of 0.1. An exception was cyclohexanone, which has the ability to extract small amounts of ions itself. The highest separation factors between Dy and the light REEs (Nd and Pr) were observed with a 0.01 M solution of TODGA in Solvent 70. REEs, as group, were extracted with 0.1 M solutions of TODGA in all diluents except for cyclohexanone, which led to extraction of Al and B at amounts greater than 10%. Stripping with over 98% efficiency was achieved using MQ water in one step.

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Section: Introductionmentioning

confidence: 99%

Characterization and Leaching of Neodymium Magnet Waste and Solvent Extraction of the Rare-Earth Elements Using TODGA

Gergorić

Ekberg

Foreman

et al. 2017

J. Sustain. Metall.

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“…The described analysis does not take into account the potential future changes in the processing of end-of-life cars; as such, disassembly before shredding will not be discussed in detail. Using minimum and maximum values for the Nd content in shredder feed (light duty vehicle/LDVs, household appliances, other sources) as described by us previously [10], two different scenarios were considered in our forecast for the next 20 years: (1) Hybrid vehicle (HEVs) and electric vehicles (EVs) are not shredded with conventional LDVs and household appliances and (2) HEVs and EVs are shredded with conventional LDVs and household appliances. This distinction is important to arrive at accurate conclusions due to the much higher Nd content of HEVs and EVs when compared to conventional vehicles [11].…”

Section: Introductionmentioning

confidence: 99%

Rare Earth Recycling: Forecast of Recoverable Nd from Shredder Scrap and Influence of Recycling Rates on Price Volatility

Bandara

Mantell

Darcy

et al. 2015

J. Sustain. Metall.

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This manuscript quantifies the recoverability of the rare earth (RE) element neodymium from shredder scrap during the next two decades and provides a forecast of recycling rates until 2034 based on these calculations. In combination with this forecast, an analysis of historical price and recycling trends for several critical (i.e., platinum group metals, zinc, tantalum, cobalt, antimony, and tungsten) and non-critical materials (i.e., tin, chromium, gold, and copper) results in general conclusions for the future price volatility of REs in dependence on expected recycling rates.

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“…Despite this assertion, as recently as 2011, less than 1% of RE-containing materials were being recycled (21). These low recycling rates stem from a combination of sporadic collection procedures and lack of efficient separations and preprocessing steps (22)(23)(24)(25)(26)(27).To contribute to incentivizing the "urban mining" of REcontaining materials, we recently initiated efforts toward new, simplified methods in RE separations (28). Our initial work focused on the separation of neodymium (Nd) and dysprosium (Dy), two key components of neomagnets (Nd 2 Fe 14 B).…”

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confidence: 99%

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confidence: 99%

Accomplishing simple, solubility-based separations of rare earth elements with complexes bearing size-sensitive molecular apertures

Bogart

Cole

Boreen

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Rare earth (RE) metals are critical components of electronic materials and permanent magnets. Recycling of consumer materials is a promising new source of rare REs. To incentivize recycling, there is a clear need for the development of simple methods for targeted separations of mixtures of RE metal salts. Metal complexes of a tripodal hydroxylaminato ligand, TriNOx 3-, featured a size-sensitive aperture formed of its three η 2 -(N,O) ligand arms. Exposure of cations in the aperture induced a self-associative equilibrium comprising RE(TriNOx)THF and [RE(TriNOx)] 2 species. Differences in the equilibrium constants K dimer for early and late metals enabled simple separations through leaching. Separations were performed on RE1/RE2 mixtures, where RE1 = La-Sm and RE2 = Gd-Lu, with emphasis on Eu/Y separations for potential applications in the recycling of phosphor waste from compact fluorescent light bulbs. Using the leaching method, separations factors approaching 2,000 were obtained for early-late RE combinations. Following solvent optimization, >95% pure samples of Eu were obtained with a 67% recovery for the technologically relevant Eu/Y separation. (11)(12)(13)(14). Limitations associated with their beneficiation and separations, especially their solvent-, waste-, and energy intensities, have contributed to the concentration of suppliers in the People's Republic of China. Supply risks for these elements have emerged, particularly in the face of current and growing demand in the next 20 y (15, 16). Because the global marketplace for these elements is dominated by a single source (17), prices for primary rare earth (RE) materials are volatile (18). As a result, the US Department of Energy has classified many of these elements as "critical" (19). There is a clear need to find potential new supplies of these elements.Recent life cycle assessments have indicated that recycling of consumer materials is a promising alternative to conventional production processes (20). Despite this assertion, as recently as 2011, less than 1% of RE-containing materials were being recycled (21). These low recycling rates stem from a combination of sporadic collection procedures and lack of efficient separations and preprocessing steps (22)(23)(24)(25)(26)(27).To contribute to incentivizing the "urban mining" of REcontaining materials, we recently initiated efforts toward new, simplified methods in RE separations (28). Our initial work focused on the separation of neodymium (Nd) and dysprosium (Dy), two key components of neomagnets (Nd 2 Fe 14 B). We disclosed the development of the tripodal nitroxide ligand, [((2-t BuNO)C 6 H 4 CH 2 ) 3 N] 3− (TriNOx 3-), which induced a selfassociation equilibrium between monomeric Nd(TriNOx)THF/ dimeric [Nd(TriNOx)] 2 species. The position of this equilibrium was found to be strongly dependent on the size of the RE cation. We showed proof of concept that differences in the self-association equilibrium constants between Nd and Dy could be exploited to achieve 95% pure materials through a simple leachi...

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Value Analysis of Neodymium Content in Shredder Feed: Toward Enabling the Feasibility of Rare Earth Magnet Recycling

Cited by 37 publications

References 27 publications

Characterization and Leaching of Neodymium Magnet Waste and Solvent Extraction of the Rare-Earth Elements Using TODGA

Characterization and Leaching of Neodymium Magnet Waste and Solvent Extraction of the Rare-Earth Elements Using TODGA

Rare Earth Recycling: Forecast of Recoverable Nd from Shredder Scrap and Influence of Recycling Rates on Price Volatility

Accomplishing simple, solubility-based separations of rare earth elements with complexes bearing size-sensitive molecular apertures

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