Separation and recovery of neodymium and praseodymium from permanent magnet scrap through the hydrometallurgical route

Parhi, Pankaj Kumar; Sethy, Tikina Rani; Rout, P.C.; Sarangi, K.

doi:10.1080/01496395.2016.1200087

Cited by 44 publications

(12 citation statements)

References 28 publications

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“…Optimum conditions for this process were S:L (solid-to-liquid ratio) ratio of 20 g/L, leaching time of 15 min, and concentrations of 3 mol/L HCl and 1.5 mol/L H 2 SO 4 . The vast majority of research so far has been conducted using strong mineral acids for leaching [12][13][14][15]. The extraction of the metals of interest after leaching is most commonly done using solvent extraction agents like di-(2-ethylhexyl) phosphoric acid (D2EHPA), tributyl phosphate (TBP) and 2-ethylhexyl phosphonic acid (HEHEHP) [16], although a lot of research in recent years has been focused on the investigation of solvent extraction using ionic liquids as promising new, environmentally friendly extractants [3,17].…”

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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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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“…For instance, for a fixed leaching time (240 min) and temperature (30 • C), by increasing HCl concentration from 0.05 to 0.3 M or reducing particle size of alloy powders (from 151-180 to 76-105 µm), Nd leaching efficiency has been increased to~99.9% in HCl. The latter effect is attributed to the increased active surface area of the smaller particles, which resulted in higher metal dissolution [31].…”

Section: Recovery Of Nd Via Hydrometallurgymentioning

confidence: 99%

Analysis of Sustainable Methods to Recover Neodymium

Periyapperuma

Sanchez-Cupido

Pringle

et al. 2021

Sustainable Chemistry

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Neodymium (Nd) is one of the most essential rare-earth metals due to its outstanding properties and crucial role in green energy technologies such as wind turbines and electric vehicles. Some of the key uses includes permanent magnets present in technological applications such as mobile phones and hard disk drives, and in nickel metal hydride batteries. Nd demand is continually growing, but reserves are severely limited, which has put its continued availability at risk. Nd recovery from end-of-life products is one of the most interesting ways to tackle the availability challenge. This perspective concentrates on the different methods to recover Nd from permanent magnets and rechargeable batteries, covering the most developed processes, hydrometallurgy and pyrometallurgy, and with a special focus on electrodeposition using highly electrochemical stable media (e.g., ionic liquids). Among all the ionic liquid chemistries, only phosphonium ionic liquids have been studied in-depth, exploring the impact of temperature, electrodeposition potential, salt concentration, additives (e.g., water) and solvation on the electrodeposition quality and quantity. Finally, the importance of investigating new ionic liquid chemistries, as well as the effect of other metal impurities in the ionic liquid on the deposit composition or the stability of the ionic liquids are discussed. This points to important directions for future work in the field to achieve the important goal of efficient and selective Nd recovery to overcome the increasingly critical supply problems.

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“…Numerous approaches for recycling rare-earth elements from scrap have been developed, including selective precipitation [4], solvent extraction [5][6][7][8][9] and cationic exchange [1]. Amongst these approaches, the first step in recycling rare-earth elements is dissolving scrap in strong acids, including sulphuric, nitric and hydrochloric acids [5,6,10].…”

Section: Introductionmentioning

confidence: 99%

Resource Recovery of Waste Nd–Fe–B Scrap: Effective Separation of Fe as High-Purity Hematite Nanoparticles

Zhu

Chen

et al. 2020

Sustainability

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Recycling rare-earth elements from Nd magnet scrap (Nd–Fe–B scrap) is a highly economical process; however, its efficiency is low due to large portions of Fe impurity. In this study, the effective separation of Fe impurity from scrap was performed through an integrated nitric acid dissolution and hydrothermal route with the addition of fructose. Results showed that more than 99% of the scrap was dissolved in nitric acid, and after three dilutions that the Nd, Pr, Dy and Fe concentrations in the diluted acid were 9.01, 2.11, 0.37 and 10.53 g/L, respectively. After the acid was hydrothermally treated in the absence of fructose, only 81.8% Fe was removed as irregular hematite aggregates, whilst more than 98% rare-earth elements were retained. By adding fructose at an Mfructose/Mnitrate ratio of 0.2, 99.94% Fe was precipitated as hematite nanoparticles, and the loss of rare-earth elements was <2%. In the treated acid, the residual Fe was 6.3 mg/L, whilst Nd, Pr and Dy were 8.84, 2.07 and 0.36 g/L, respectively. Such composition was conducive for further recycling of high-purity rare-earth products with low Fe impurity. The generated hematite nanoparticles contained 67.92% Fe with a rare-earth element content of <1%. This value meets the general standard for commercial hematite active pharmaceutical ingredients. In this manner, a green process was developed for separating Fe from Nd–Fe–B scrap without producing secondary waste.

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Separation and recovery of neodymium and praseodymium from permanent magnet scrap through the hydrometallurgical route

Cited by 44 publications

References 28 publications

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

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

Analysis of Sustainable Methods to Recover Neodymium

Resource Recovery of Waste Nd–Fe–B Scrap: Effective Separation of Fe as High-Purity Hematite Nanoparticles

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