Extraction of Rare Earth Elements as Oxides from a Neodymium Magnetic Sludge

Nakamoto, Masashi; Kubo, Kenji; Katayama, Yohei; Tanaka, Toshihiro; Yamamoto, Tomokazu

doi:10.1007/s11663-011-9618-y

Cited by 48 publications

(30 citation statements)

References 16 publications

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“…The second group includes processes by Saito et al [38], who developed the RE recovery process using glass slag whereby RE contained in REPM waste are oxidized and extracted into B 2 O 3 flux (Route No. 7 in Tables 2 and 3) and the method developed by Nakamoto et al [10] to separate REO from Fe-B using carbon as contact material (Route No. 9 in Tables 2 and 3).…”

Section: Recycling or Recovery Via Oxidationmentioning

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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Section: Recycling or Recovery Via Oxidationmentioning

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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“…Most of the Fe remained in the metal phase. From the cross-sectional morphology, it can be seen that the oxide phases covered more evidently the metal phase, whereas the interface between the two phases became rough, as the experimental temperature increased [1].…”

Section: Extraction Of Rare Earth Elements From Ndfeb Magnetmentioning

confidence: 99%

“…6, 7). Under the experimental condition (1,673-1,823 K, 1-9 h) and the amount of extraction agents employed, all the rare earth in the metal phase were exhausted, and reduction of B 2 O 3 in oxide phase was carried out by carbon from the metal phase [1]. Carbothermic reduction of B 2 O 3 occurs at relatively high temperature, higher than 1,873 K, as shown in Fig.…”

Section: Rare Earth Elements In the Oxide Phasementioning

confidence: 99%

“…The NdFeB permanent magnets contain more than 30 mass% of rare earth elements [1]. It is estimated that 20-30 % neodymium magnets scraps will be produced in the manufacturing process, e.g., processing, sintering, cutting, and polishing [2].…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, the processes based on the high temperature pyrometallurgical treatments have now attracted more attention for their smaller environmental impacts. Owing to the strong affinity of oxygen to rare earth elements, Nakamoto et al reported the extraction of REEs in the form of oxides from neodymium magnetic sludge in 2011 [1]. They found that the boron oxide concentration in the slag phase was decreasing with increasing the holding time in a graphite crucible at 1,723 K. The extraction of Nd from the waste NdFeB alloys by the glass slag method was also proposed by Saito et al in 2003 [8].…”

Section: Introductionmentioning

confidence: 99%

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Extraction of Rare Earth Elements from Permanent Magnet Scraps by FeO–B2O3 Flux Treatment

Bian

Guo

Jiang

et al. 2015

J. Sustain. Metall.

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In order to recover the rare earth elements (REEs) from neodymium permanent magnet scraps, Fe 2 O 3 , B 2 O 3 , and FeO-B 2 O 3 fluxes were designed to extract the REEs. The REEs containing oxides were successfully separated from the Fe-based metals at the temperatures of 1,673, 1,773, and 1,823 K. A mechanism for extraction of REEs has been proposed based mainly on the experimental observations using the flux of FeOÁB 2 O 3 at 1,573 K. Effects of temperature and reaction time were also investigated. The experimental results have shown that increasing temperature and prolonging holding time help the reduction of B 2 O 3 contents in the oxide phase. The FeO-B 2 O 3 fluxes show better extraction efficiency. The purity of rare earth oxide was 98.4 % produced by 2FeOÁB 2 O 3 and the extraction ratios were higher than 99.5 % after the FeO-B 2 O 3 fluxes treatment.

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