Large batch recycling of waste Nd–Fe–B magnets to manufacture sintered magnets with improved magnetic properties

LI, Xinrui; Yue, Ming; Liu, W.Q.; Li, X.L.; Yi, Xiaolan; Huang, Xiulian; Zhang, D.T.; Chen, J.W.

doi:10.1016/j.jallcom.2015.07.201

Cited by 33 publications

(18 citation statements)

References 16 publications

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“…Zakotnik et al [51] added 1.0 wt.% Nd to recycled jet-milled NdFeB powders, which was sufficient to recover the magnetic properties through a hydrogen decrepitation (HD) method. Li et al blended recycled milled NdFeB magnets with 24 wt.% Nd 22 PrFe 14 B powder, which restored B r to 99.2 pct, i H c to 105.65 pct, and (BH) max to 98.65 pct [52,53]. In two separate studies, the use of DyF 3 salt to produce (Nd,Dy) 2 Fe 14 B shell on the surface of recycled powders was proposed [53,54].…”

Section: Innovation Of Alternative Permanent Magnetic Materialsmentioning

confidence: 99%

The Impact of Magnetic Materials in Renewable Energy‐Related Technologies in the 21st Century Industrial Revolution: The Case of South Africa

Matizamhuka

2018

Advances in Materials Science and Engineering

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Magnetic materials specifically permanent magnets are critical for the efficient performance of many renewable energy technologies. The increased reliance on renewable energy sources has accelerated research in energy-related technologies the world over. The use of rare-earth (RE) metals in permanent magnets continues to be a source of greater concern owing to the limited RE supply coupled with dwindling reserves on the globe. This review focuses on how this has impacted on the state-of-the-art magnetic materials that continue to play a pivotal role in driving renewable energy technologies. Magnetic materials are perceived as key in driving the 21st century industrial revolution, and the participation of South Africa in this energy paradigm is critical in driving a new industrial revolution within the African continent. A number of opportunities are highlighted, and clarity is given on the several ubiquitous misconceptions and the risks on the heavy reliance on a single source for RE magnetic materials.

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Section: Innovation Of Alternative Permanent Magnetic Materialsmentioning

confidence: 99%

The Impact of Magnetic Materials in Renewable Energy‐Related Technologies in the 21st Century Industrial Revolution: The Case of South Africa

Matizamhuka

2018

Advances in Materials Science and Engineering

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“…Porosity control and, consequently, density can be carefully controlled by using powder metallurgy. Presence of pores within the microstructure of a permanent magnet is detrimental to the final properties as the pore is an empty volume that does not contribute to the remanence (Zakotnik et al, 2006;Zakotnik et al, 2008;Zakotnik et al, 2009;Degri, 2014;Li et al, 2015). In addition, it may act as a nucleation site which may cause a decrease in intrinsic coercivity by reversing magnetic domains.…”

Section: Uniquenessmentioning

confidence: 99%

Imanes Permanentes y su Producción por Pulvimetalurgia

Lalana

2018

REVMETAL

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En este estudio se ha revisado la relación histórica entre la pulvimetalurgia y los imanes permanentes. La pulvimetalurgia es una técnica de fabricación basada en la compactación de polvos que son sinterizados para crear un producto sólido. Esta técnica fue utilizada en la producción de imanes permanentes por primera vez en el siglo XVIII y, hoy en día, la mayoría de materiales magnéticos permanentes se fabrican de esta forma. Las propiedades magnéticas dependen de la microestructura del producto final, de la alineación de los dominios magnéticos y de la presencia de porosidad; y la pulvimetalurgia permite un control adecuado de estos factores.

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“…Périgo et al [77] employed the HDDR process to recycle N42 sintered magnets to make isotropic powders and investigated the effect of recombination temperature and H 2 pressure on the magnetic properties of recycled magnets. Li et al [46,78,79] studied the influence of particle distribution and hydrogenation conditions, and found that (1) the oxygen content decreases rapidly as particle size distribution increases and (2) higher H 2 pressure during hydrogenation results in decreasing oxygen content. Both Sheridan et al [80] and Gutfleisch et al [81] used a higher processing pressure during disproportionation and avoided subsequent oxygen exposure by performing both the v-HD and s-DR processes in the same furnace.…”

Section: Recycling Via Hydrogenationmentioning

confidence: 99%

Review of High-Temperature Recovery of Rare Earth (Nd/Dy) from Magnet Waste

Firdaus

Rhamdhani

Durandet

et al. 2016

J. Sustain. Metall.

103

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Rare-earth metals, particularly neodymium, dysprosium, and praseodymium are becoming increasingly important in the transition to a green economy due to their essential role in permanent magnet applications such as in electric motors and generators. With the increasingly limited rare-earth supply and complexity of processing Nd, Dy, and Pr from primary ores, recycling of rare-earth based magnets has become a necessary option to manage supply and demand. Depending on the form of the starting material (sludge or scrap), there are different routes that can be used to recover neodymium from secondary sources, ranging from hydrometallurgical (based on its primary production process), electrochemical to pyrometallurgical. Pyrometallurgical routes provide solution in cases where water is scarce and generation of waste is to be limited. This paper presents a systematic review of previous studies on the high-temperature (pyrometallurgical) recovery of rare earths from magnets. The features and conditions at which the recycling processes had been studied are mapped and evaluated technically. The review also highlights the reaction mechanisms, behaviors of the rare-earth elements, and the formation of intermediate compounds in high-temperature recycling processes. Recommendations for further scientific research to enable the development of recovery of the rare-earth and magnet recycling are also presented.

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Large batch recycling of waste Nd–Fe–B magnets to manufacture sintered magnets with improved magnetic properties

Cited by 33 publications

References 16 publications

The Impact of Magnetic Materials in Renewable Energy‐Related Technologies in the 21st Century Industrial Revolution: The Case of South Africa

The Impact of Magnetic Materials in Renewable Energy‐Related Technologies in the 21st Century Industrial Revolution: The Case of South Africa

Imanes Permanentes y su Producción por Pulvimetalurgia

Review of High-Temperature Recovery of Rare Earth (Nd/Dy) from Magnet Waste

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