Recovery Process Development for the Rare Earths from Permanent Magnet Scraps Leach Liquors

Yoon, Ho-Sung; Kim, Chul-Joo; Chung, Kyeong Woo; Kim, Sung-Don; Kumar, J. Rajesh

doi:10.5935/0103-5053.20150077

Cited by 16 publications

(21 citation statements)

References 1 publication

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“…Extraction becomes a very useful tool when choosing a suitable solvent [11][12][13][14][15]. The rare earth solutions were prepared by the dissolution of the peroxycarbonate precipitate of Dy, Gd, and traces of Yb with HCl.…”

Section: Extraction Experimentsmentioning

confidence: 99%

“…Yttrium and dysprosium is separated via solvent extraction technique from different acid media using different solvents such as Cyanex 923, bis (2, 4, 4-trimethylpentyl) dithiophosphinic acid, sec-octylphenoxy acetic acid [CA12] synergtic with bis (2, 4-4-trimethylpentyl) phosphinic acid [Cyanex 272], and trialkyl phosphine oxide (TPO) [11][12][13][14][15]. Mohammadi et al (2015) studied the separation of Dy, Nd, and Y by solvent extraction using D2EHPA and EHEHPA.…”

Section: Introductionmentioning

confidence: 99%

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Recovery of Yttrium and Dysprosium from the Rare Earth Concentrate, Southwestern Sinai, Egypt

Fawzy

El-Hady

2018

Arab Journal of Nuclear Sciences and Applications

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Section: Extraction Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Recovery of Yttrium and Dysprosium from the Rare Earth Concentrate, Southwestern Sinai, Egypt

Fawzy

El-Hady

2018

Arab Journal of Nuclear Sciences and Applications

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“…Production scrap of Nd-Fe-B permanent magnets, or just Nd-Fe-B production scrap, is currently considered as the most valuable secondary resource of neodymium and dysprosium [1]. Several flowsheets have been developed for the recovery of rare-earth elements (REEs) from Nd-Fe-B scrap, via direct or indirect recycling [1][2][3][4][5][6][7][8]. Roasting of Nd-Fe-B permanent magnets is known to improve the selectivity and the dissolution rate of the consequent leaching step [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Selective Roasting of Nd–Fe‒B Permanent Magnets as a Pretreatment Step for Intensified Leaching with an Ionic Liquid

Orefice

Bulck

Blanpain

et al. 2019

J. Sustain. Metall.

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Oxidative roasting of Nd-Fe-B permanent magnets prior to leaching improves the selectivity in the recovery of rare-earth elements over iron. However, the dissolution rate of oxidatively roasted Nd-Fe-B permanent magnets in acidic solutions is very slow, often longer than 24 h. Upon roasting in air at temperatures above 500 °C, the neodymium metal is not converted to Nd 2 O 3 , but rather to the ternary NdFeO 3 phase. NdFeO 3 is much more difficult to dissolve than Nd 2 O 3. In this work, the formation of NdFeO 3 was avoided by roasting Nd-Fe-B permanent magnet production scrap in argon atmosphere, having an oxygen content of p O 2 ≤ 10 −20 atm, with the addition of 5 wt% of carbon as an iron reducing agent. For all the non-oxidizing iron roasting conditions investigated, the iron in the Nd-Fe-B scrap formed a cobalt-containing metallic phase, clearly distinct from the rare-earth phase at microscopic level. The thermal treatment was optimized to obtain a clear phase separation of metallic iron and rare-earth phase also at the macroscopic level, to enable easy mechanical removal of iron prior to the leaching step. The sample roasted at the optimum conditions (i.e., 5 wt% carbon, no flux, no quenching step, roasting temperature of 1400 °C and roasting time of 2 h) was leached in the water-containing ionic liquid betainium bis(trifluoromethylsulfonyl)imide, [Hbet][Tf 2 N]. A leaching time of only 20 min was sufficient to completely dissolve the rare-earth elements. The rare-earth elements/iron ratio in the leachate was about 50 times higher than the initial rare-earth elements/iron ratio in the Nd-Fe-B scrap. Therefore, roasting in argon with addition of a small amount of carbon is an efficient process step to avoid the formation of NdFeO 3 and to separate the rare-earth elements from the iron, resulting in selective leaching for the recovery of rare-earth elements from Nd-Fe-B permanent magnets.

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“…Traditional multi-stage solvent extraction results in organic solvent byproduct waste. Extraction and recovery of REEs from end-of-life products is very similar to recovery of REEs from ore, in that strong mineral acid usage to dissolve REEs from the various matrices is the most feasible approach as evidenced by the majority of reports in literature where end-of-life products are concerned [13][14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Extraction of Rare Earth Elements from Chloride Media with Tetrabutyl Diglycolamide in 1-Octanol Modified Carbon Dioxide

Case

Fox

Baek

et al. 2019

Metals

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Rare earth elements (REEs) are critical to our modern world. Recycling REEs from used products could help with potential supply issues. Extracting REEs from chloride media with tetrabutyl diglycolamide (TBDGA) in carbon dioxide could help recycle REEs with less waste than traditional solvents. Carbon dioxide as a solvent is inexpensive, inert, and reusable. Conditions for extraction of Eu from aqueous chloride media were optimized by varying moles percent of 1-octanol modifier, temperature, pressure, Eu concentration, TBDGA concentration, Cl− concentration, and HCl concentration. These optimized conditions were tested on a Y, Ce, Eu, Tb simulant material, REEs containing NdFeB magnets, and lighting phosphor material. The optimized conditions were found to be 23 °C, 24.1 MPa, 0.5 mol% 1-octanol, with an excess of TBDGA. At these conditions 95 ± 2% Eu was extracted from 8 M (mol/m3) HCl. Extraction from the mixed REE simulate material resulted in separation of Y, Eu, and Tb from the Ce which remained in the aqueous solution. The extraction on NdFeB magnet dissolved into 8 M HCl resulted in extraction of Pr, Nd, Dy, and Fe >97%. This results in a separation from B, Al, and Ni. Extraction from a trichromatic lighting phosphor leachate resulted in extraction of Y and Eu >93% and no extraction of Ba, Mg, and Al.

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Recovery Process Development for the Rare Earths from Permanent Magnet Scraps Leach Liquors

Cited by 16 publications

References 1 publication

Recovery of Yttrium and Dysprosium from the Rare Earth Concentrate, Southwestern Sinai, Egypt

Recovery of Yttrium and Dysprosium from the Rare Earth Concentrate, Southwestern Sinai, Egypt

Selective Roasting of Nd–Fe‒B Permanent Magnets as a Pretreatment Step for Intensified Leaching with an Ionic Liquid

Extraction of Rare Earth Elements from Chloride Media with Tetrabutyl Diglycolamide in 1-Octanol Modified Carbon Dioxide

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