Leaching kinetics of neodymium in sulfuric acid from E-scrap of NdFeB permanent magnet

Yoon, Ho-Sung; Kim, Chul-Joo; Chung, Kyeong Woo; Lee, Su-Jeong; Joe, Aram; Shin, Yang-Ho; Lee, Se-Il; Yoo, Seung-Joon; Kim, Jin-Geol

doi:10.1007/s11814-013-0259-5

Cited by 56 publications

(28 citation statements)

References 8 publications

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“…Heating improves the kinetics of the leaching process, as noted by Yoon et al (2014a) when studying the leaching kinetics of NdFeB magnet powder with sulphuric acid. Optimum leaching conditions in this case were determined to be 3 M sulphuric acid, 4 h leaching time, 70°C and a pulp density of 110.8 g/L.…”

Section: Leaching Of Reesmentioning

confidence: 90%

Reclaiming rare earth elements from end-of-life products: A review of the perspectives for urban mining using hydrometallurgical unit operations

et al. 2015

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Section: Leaching Of Reesmentioning

confidence: 90%

Reclaiming rare earth elements from end-of-life products: A review of the perspectives for urban mining using hydrometallurgical unit operations

et al. 2015

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“…The optimal conditions were a solid-to-liquid ratio (S:L) of 20 g/L, 15 min leaching time, and 3 M hydrochloric acid or 1.5 M sulphuric acid. In 2014, Yoon et al [14] carried out a similar investigation and reported that increasing the leaching temperature gave an increased leaching effect of H 2 SO 4 when leaching the NdFeB magnetic scrap. The optimal leaching conditions were determined to be 4 h leaching time at 70°C using 3 M H 2 SO 4 .…”

Section: Introductionmentioning

confidence: 99%

Separation of Heavy Rare-Earth Elements from Light Rare-Earth Elements Via Solvent Extraction from a Neodymium Magnet Leachate and the Effects of Diluents

Gergorić

Ekberg

Steenari

et al. 2017

J. Sustain. Metall.

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In recent decades, rare-earth elements (REEs) have seen a considerable increase in usage in modern technologies and the so-called green energy sources. The REEs are currently regarded to be among the most critical elements by the European Union (EU) and the United States (USA). Large investments are made in the research of recycling of the REEs from end-of-life products and E-scrap. One potential source for recycling of larger amounts of neodymium and dysprosium are end-of-life neodymium magnets. In this work, the selective extraction of REEs from a sulfuric media leachate (containing Nd, Dy, Pr, Gd, Co, and B) obtained by selective roasting of NdFeB waste and leaching was investigated. The extracting agent D2EHPA (di-(2-ethylhexyl) phosphoric acid) diluted in Solvent 70, hexane, octane, cyclohexanone, chloroform, 1-octanol, and toluene was used for the investigation of the effects of using different diluents on the extraction of REEs and the separation between the light and the heavy REEs. The concentrations of D2EHPA in the used diluents were 0.3, 0.6, 0.9, and 1.2 M. The highest separation factors between the heavy and the light REEs were achieved using 0.3 M D2EHPA in hexane, while no B or Co extraction was measurable. The REEs were completely extracted as a group using 0.9 M or 1.2 M D2EHPA in either octane or hexane, also with no B or Co extraction. The aliphatic nonpolar diluents showed better properties than the aromatic and polar ones. The complete stripping of REEs from the loaded organic phases was proven to be efficient using hydrochloric acid at concentrations of 2 M or higher.

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“…After drying and high-temperature treatment, the powder was leached in demineralized water for 15 min to 24 h, which led to >95% recovery of REEs while Fe remained in the solid residue in the form of a sulfate. In 2014, Yoon et al [10] studied the leaching of NdFeB magnet scrap using H 2 SO 4 at different temperatures and concentrations. The optimal leaching conditions were determined to be 70 • C and 3 mol/L H 2 SO 4 with a leaching time of 4 h. In 2013, Lee et al [11] carried out an investigation on leaching of NdFeB magnets using H 2 SO 4 , HCl, HNO 3 , and NaOH.…”

Section: Introductionmentioning

confidence: 99%

Leaching and Recovery of Rare-Earth Elements from Neodymium Magnet Waste Using Organic Acids

Gergorić

Ravaux²,

Steenari

et al. 2018

Metals

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Over the last decade, rare-earth elements (REEs) have become critical in the European Union (EU) in terms of supply risk, and they remain critical to this day. End-of-life electronic scrap (e-scrap) recycling can provide a partial solution to the supply of REEs in the EU. One such product is end-of-life neodymium (NdFeB) magnets, which can be a feasible source of Nd, Dy, and Pr. REEs are normally leached out of NdFeB magnet waste using strong mineral acids, which can have an adverse impact on the environment in case of accidental release. Organic acids can be a solution to this problem due to easier handling, degradability, and less poisonous gas evolution during leaching. However, the literature on leaching NdFeB magnets waste with organic acids is very scarce and poorly investigated. This paper investigates the recovery of Nd, Pr, and Dy from NdFeB magnets waste powder using leaching and solvent extraction. The goal was to determine potential selectivity between the recovery of REEs and other impurities in the material. Citric acid and acetic acid were used as leaching agents, while di-(2-ethylhexyl) phosphoric acid (D2EHPA) was used for preliminary solvent extraction tests. The highest leaching efficiencies were achieved with 1 mol/L citric acid (where almost 100% of the REEs were leached after 24 h) and 1 mol/L acetic acid (where >95% of the REEs were leached). Fe and Co—two major impurities—were co-leached into the solution, and no leaching selectivity was achieved between the impurities and the REEs. The solvent extraction experiments with D2EHPA in Solvent 70 on 1 mol/L leachates of both acetic acid and citric acid showed much higher affinity for Nd than Fe, with better extraction properties observed in acetic acid leachate. The results showed that acetic acid and citric acid are feasible for the recovery of REEs out of NdFeB waste under certain conditions.

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Leaching kinetics of neodymium in sulfuric acid from E-scrap of NdFeB permanent magnet

Cited by 56 publications

References 8 publications

Reclaiming rare earth elements from end-of-life products: A review of the perspectives for urban mining using hydrometallurgical unit operations

Reclaiming rare earth elements from end-of-life products: A review of the perspectives for urban mining using hydrometallurgical unit operations

Separation of Heavy Rare-Earth Elements from Light Rare-Earth Elements Via Solvent Extraction from a Neodymium Magnet Leachate and the Effects of Diluents

Leaching and Recovery of Rare-Earth Elements from Neodymium Magnet Waste Using Organic Acids

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