The extraction of Nd from waste Nd–Fe–B alloys by the glass slag method

Saito, Tetsuji; Sato, Hiroo; Ozawa, Shumpei; Yu, Juan; Motegi, Tetsuichi

doi:10.1016/s0925-8388(02)01202-1

Cited by 102 publications

(46 citation statements)

References 13 publications

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“…It has been well known that Nd could be obtained from NdFeB magnet scraps by sulfuric acid leaching followed by precipitation of Nd salts [6][7][8]. Because this method dissolves iron as well as neodymium, there are disadvantages such as high consumption of sulfuric acid and large amount of wastewater discharged.…”

Section: Introductionmentioning

confidence: 99%

“…Because this method dissolves iron as well as neodymium, there are disadvantages such as high consumption of sulfuric acid and large amount of wastewater discharged. Many methods have been reported to extract selectively Nd from waste NdFeB magnets such as roasting followed by sulfuric acid leaching [9], selective chlorination of Nd using NH4Cl [4], selective extraction of Nd using molten Mg [5,10] and slag materials [6], and leaching with hydrochloric acid and oxalic acid [11]. These methods require strong acid or should be performed at high temperature over 700 °C.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Grinding and Roasting Conditions on the Selective Leaching of Nd and Dy from NdFeB Magnet Scraps

Yoon

Kim

Chung

et al. 2015

Metals

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Abstract:The pretreatment processes consisting of grinding followed by roasting were investigated to improve the selective leaching of Nd and Dy from neodymium-iron-boron (NdFeB) magnet scraps. The peaks of Nd(OH)3 and Fe were observed in XRD results after grinding with NaOH as the amount of water addition increased to 5 cm 3 . These resultsindicate that the components of Nd and Fe in NdFeB magnet could be changed successfully into Nd(OH)3 and Fe, respectively. In the roasting tests using the ground product, with increasing roasting temperature to 500 °C, the peaks of Nd(OH)3 and Fe disappeared while those of Nd2O3 and Fe2O3 were shown. The peaks of NdFeO3 in the sample roasted at 600 °C were observed in the XRD pattern. Consequently, 94.2%, 93.1%, 1.0% of Nd, Dy, Fe were leached at 400 rpm and 90 °C in 1 kmol· m −3 acetic acid solution with 1% pulp density using a sample prepared under the following conditions: 15 in stoichiometric molar ratio of NaOH:Nd, 550 rpm in rotational grinding speed, 5 cm 3 in water addition, 30 min in grinding time, 400 °C and 2 h in roasting temperature and time. The results indicate that the selective leaching of Nd and Dy from NdFeB magnet could be achieved successfully by grinding and then roasting treatments. OPEN ACCESSMetals 2015, 5 1307

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effect of Grinding and Roasting Conditions on the Selective Leaching of Nd and Dy from NdFeB Magnet Scraps

Yoon

Kim

Chung

et al. 2015

Metals

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“…As summarized in Tables 1 and 2, the former removes oxygen using calciothermic reduction to reduce REOs without melting the magnet, while the latter uses flux to extract REOs from the waste to recover Nd-Fe-B alloy. 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.…”

Section: Recycling or Recovery Via Oxidationmentioning

confidence: 99%

“…Saito et al [38] developed a method using a glass slag whereby magnet scrap is melted and brought into contact with a molten flux exploiting the strong affinity of REs with the slag. During undercooling, a reaction between molten alloy and flux takes place to selectively dissolve the REs from the alloys and supercool to a glass.…”

Section: Separation Of Re As Reos From Oxidized Magnet Wastementioning

confidence: 99%

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

Firdaus

Rhamdhani

Durandet

et al. 2016

J. Sustain. Metall.

108

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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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“…Recently, we have succeeded in the recovery of Nd from Nd-Fe-B magnets by the reaction between the molten Nd-Fe-B materials and the molten glass slag materials. 9) In this study, the use of the glass slag method in the extraction of Sm from the Sm-Co magnets, which have become renewed interests as the high temperature permanent magnets. 10,11) The degree of the extraction of Sm from the Sm-Co alloys is evaluated by chemical and microstructural analyses of the Sm-Co alloys processed by the glass slag method.…”

Section: Introductionmentioning

confidence: 99%

The Extraction of Sm from Sm-Co alloys by the Glass Slag Method

et al. 2003

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The use of the glass slag method in the extraction of Sm from Sm-Co alloys was studied. The magnetic SmCo 5 phase decomposed into Sm oxide phase and Co phases by the glass slag method. The Sm oxide phase was extracted by the surrounding molten glass slag materials in the glass slag method. The resultant alloys consisted of neither SmCo 5 phase nor Sm oxide phase. In the glass slag method, the Sm-Co alloys were separated into Sm-containing glass slag material and a Co-B alloy. The glass slag method was suitable for the extraction of samarium from the Sm-Co alloys as was the case for the extraction of neodymium from the Nd-Fe-B alloys.

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The extraction of Nd from waste Nd–Fe–B alloys by the glass slag method

Cited by 102 publications

References 13 publications

The Effect of Grinding and Roasting Conditions on the Selective Leaching of Nd and Dy from NdFeB Magnet Scraps

The Effect of Grinding and Roasting Conditions on the Selective Leaching of Nd and Dy from NdFeB Magnet Scraps

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

The Extraction of Sm from Sm-Co alloys by the Glass Slag Method

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