and Fuels Changzhi Li,† Xiaochen Zhao,† Aiqin Wang,† George W. Huber,†,‡ and Tao Zhang*,† †State Key Laborotary of Catalysis, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China ‡Department of Chemical and Biological Engineering, University of WisconsinMadison, Madison, Wisconsin 53706, United States

Catalytic Transformation of Lignin for the Production of Chemicals and Fuels

NdFeB permanent magnets have different life cycles, depending on the applications: from as short as 2–3 years in consumer electronics to 20–30 years in wind turbines. The size of the magnets ranges from less than 1 g in small consumer electronics to about 1 kg in electric vehicles (EVs) and hybrid and electric vehicles (HEVs), and can be as large as 1000–2000 kg in the generators of modern wind turbines. NdFeB permanent magnets contain about 31–32 wt% of rare-earth elements (REEs). Recycling of REEs contained in this type of magnets from the End-of-Life (EOL) products will play an important and complementary role in the total supply of REEs in the future. However, collection and recovery of the magnets from small consumer electronics imposes great social and technological challenges. This paper gives an overview of the sources of NdFeB permanent magnets related to their applications, followed by a summary of the various available technologies to recover the REEs from these magnets, including physical processing and separation, direct alloy production, and metallurgical extraction and recovery. At present, no commercial operation has been identified for recycling the EOL NdFeB permanent magnets and the recovery of the associated REE content. Most of the processing methods are still at various research and development stages. It is estimated that in the coming 10–15 years, the recycled REEs from EOL permanent magnets will play a significant role in the total REE supply in the magnet sector, provided that efficient technologies will be developed and implemented in practice.

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REE Recovery from End-of-Life NdFeB Permanent Magnet Scrap: A Critical Review

Phenolic hydrogen bond donors in the formation of non-ionic deep eutectic solvents: the quest for type V DES

Waste electrical and electronic equipment (WEEE) contains economically significant levels of precious, critical metals and rare earth elements, apart from base metals and other toxic compounds. Rec...

https://hal-insu.archives-ouvertes.fr/insu-02549695/document

Recent advances on hydrometallurgical recovery of critical and precious elements from end of life electronic wastes - a review

A perspective on sustainable energy materials for lithium batteries

Extraction and separation of neodymium and dysprosium from used NdFeB magnets: an application of ionic liquids in solvent extraction towards the recycling of magnets

https://pubs.rsc.org/en/content/articlepdf/2020/gc/d0gc00940g

Solvometallurgical recovery of cobalt from lithium-ion battery cathode materials using deep-eutectic solvents

Deep-eutectic solvents (DESs) are used as a promising alternative to aqueous solutions for the recovery of valuable metals from NdFeB magnets. A deep-eutectic solvent based on choline chloride and lactic acid (molar ratio 1 : 2) was used for the leaching of rare earths and other metals from NdFeB magnets. A process for the separation of Fe, B and Co from Nd and Dy in the deep-eutectic solvent was developed by using the ionic liquid tricaprylmethylammonium thiocyanate (Aliquat 336 SCN, [A336][SCN]) diluted in toluene (0.9 M). The extraction parameters were optimized and stripping of B was efficiently carried out by HCl, while EDTA was employed for the recovery of Fe and Co. The separation of Nd and Dy was assessed by using two different types of extractants, a mixture of trialkylphosphine oxides (Cyanex 923) and bis(2-ethylhexyl)phosphoric acid (D2EHPA). Based on the distribution ratios, separation factors and the ease of subsequent stripping, Cyanex 923 was chosen as the most effective extractant. The purified Dy present in the less polar phase was easily recovered by stripping with water, while the Nd present in the deep-eutectic solvent was recovered by precipitation stripping with a stoichiometric amount of oxalic acid. Nd2O3 and Dy2O3 were recovered with a purity of 99.87% and 99.94%, respectively. The feasibility to scale up this separation process was corroborated by a setup of mixer-settlers and highlighted by the possibility to fully recover and reuse the deep-eutectic solvent and the less polar phases employed in the extractions. The new proposed system based on a deep-eutectic solvent combined with traditional organic extraction phases presented higher selectivities and efficiencies than the analogous aqueous system. Extended X-ray absorption fine structure (EXAFS) was employed to elucidate the different mechanisms for extraction of Co and Fe from the deep-eutectic solvent and from an aqueous solution.

/pdf/separation-of-rare-earths-and-other-valuable-metals-from-2wj75rgcqe.pdf

Separation of rare earths and other valuable metals from deep-eutectic solvents: a new alternative for the recycling of used NdFeB magnets

Lithium is becoming increasingly important due to its essential role in lithium-ion batteries. Over 70% of the global lithium resources are found in salt lake brines, but lithium is always accompan...

Efficient and Sustainable Removal of Magnesium from Brines for Lithium/Magnesium Separation Using Binary Extractants

A solvent extraction method based on the combination of the ionic liquid trihexyl(tetradecyl)phosphonium thiocyanate or nitrate ([C101][SCN], [C101][NO3]) and the neutral extractants Cyanex 923 or tri-n-butyl phosphate (TBP) has been investigated for the separation of Nd(III) and Dy(III) from chloride media. High distribution ratios and separation factors were obtained when using Cyanex 923 diluted in [C101][SCN] 40 : 60 (wt%) and extracting from chloride media. The addition of Cyanex 923 to the ionic liquid has four advantages: (1) increase in the distribution ratios of the rare earths, (2) decrease of the viscosity of the organic phase, hence an improved mass transfer, (3) increase in the loading capacity of the ionic liquid and (4) improvement of the coalescence and phase disengagement, which is of importance when carrying out separations in continuous mode. Different extraction parameters were optimized: concentration of Cyanex 923, chloride concentration in the aqueous phase, equilibration time, pH of the aqueous phase, type of scrubbing and stripping agents. The ionic liquid combined with Cyanex 923 was recycled up to three times without losing its extraction efficiency. McCabe–Thiele diagrams were constructed to determine the number of stages needed for the separation of Nd(III) and Dy(III). Stripping of Dy(III) from the organic phase was easily achieved with water. The feasibility to run this process in continuous mode was tested in a battery of small mixer-settlers (0.12 L and 0.48 L effective volume in the mixer and the settler, respectively). As a result, this process constitutes a novel and scalable alternative for the separation of Nd(III) and Dy(III).

/pdf/separation-of-neodymium-and-dysprosium-by-solvent-extraction-1gfh5txi43.pdf

Separation of neodymium and dysprosium by solvent extraction using ionic liquids combined with neutral extractants: batch and mixer-settler experiments

Sofía Riaño

Papers

Extraction and separation of neodymium and dysprosium from used NdFeB magnets: an application of ionic liquids in solvent extraction towards the recycling of magnets

Solvometallurgical recovery of cobalt from lithium-ion battery cathode materials using deep-eutectic solvents

Separation of rare earths and other valuable metals from deep-eutectic solvents: a new alternative for the recycling of used NdFeB magnets

Efficient and Sustainable Removal of Magnesium from Brines for Lithium/Magnesium Separation Using Binary Extractants

Separation of neodymium and dysprosium by solvent extraction using ionic liquids combined with neutral extractants: batch and mixer-settler experiments