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Gallardo K, Valdivia D, Jara A, Castillo R. The importance of the pretreatment of samples in Nd quantification from NdFeB magnets through inductively coupled plasma atomic emission spectroscopy (ICP-OES)-a rapid and streamlined methodology. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2023; 58:935-941. [PMID: 37791682 DOI: 10.1080/10934529.2023.2264135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 09/15/2023] [Indexed: 10/05/2023]
Abstract
In this study, we emphasize the critical role of sample pretreatment. We report on the behavior of NdFeB magnet samples exposed to four different acid media for digestion. NdFeB magnets are becoming a significant source of neodymium, a rare-earth element critical to many technologies and a potential substitute for traditional mining of the element. To address this, we meticulously tested nitric acid, hydrochloric acid, acetic acid, and citric acid, all at a concentration of 1.6 M, as economical and environmentally friendly alternatives to the concentrated mineral acids commonly used in the leaching of these materials. The pivotal stage involves the initial characterization of samples in the solid state using SEM-EDX and XPS analysis to obtain their initial composition. Subsequently, the samples are dissolved in the four aforementioned acids. Finally, neodymium is quantified using ICP-OES. Throughout our investigation, we evaluated some analytical parameters to determine the best candidate for performing the digestion, including time, limits of detection and quantification, accuracy, recovery of spike samples, and robustness. After careful consideration, we unequivocally conclude that 1.6 M nitric acid stands out as the optimal choice for dissolving NdFeB magnet samples, with the pretreatment of the samples being the critical aspect of this report.
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Affiliation(s)
- Karem Gallardo
- Departamento de Química, Universidad Católica del Norte, Antofagasta, Chile
- Centro de Investigación Científica y Tecnológica del Agua y Sustentabilidad en el Desierto CEITSAZA, Universidad Católica del Norte, Antofagasta, Chile
| | - Dayana Valdivia
- Departamento de Química, Universidad Católica del Norte, Antofagasta, Chile
| | - Andrea Jara
- Departamento de Química, Universidad Católica del Norte, Antofagasta, Chile
- Centro de Investigación Científica y Tecnológica del Agua y Sustentabilidad en el Desierto CEITSAZA, Universidad Católica del Norte, Antofagasta, Chile
| | - Rodrigo Castillo
- Departamento de Química, Universidad Católica del Norte, Antofagasta, Chile
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2
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Krishna R, Dhass AD, Arya A, Prasad R, Colak I. An assessment of the strategies for the energy-critical elements necessary for the development of sustainable energy sources. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:90276-90297. [PMID: 37273062 PMCID: PMC10241139 DOI: 10.1007/s11356-023-28046-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 05/29/2023] [Indexed: 06/06/2023]
Abstract
There have been several strategies developed to increase the diversified supply of energy so that it can meet all of the future demands for energy. As a result, to ensure a healthy and sustainable energy future, it is imperative to warrant reliable and diverse energy supply sources if the "green energy economy" is to be realized. The purpose of developing and deploying clean energy technologies is to improve our overall energy security, reduce our carbon footprint, and ensure that the generation of energy is secure and reliable in the future, making sure that we can spur economic growth in the future. In this paper, advancements in alternative sources of energy sustainability and strategies will be examined to ensure there will be enough fuel to supply all the future demands for energy. Several emerging clean energy technologies rely heavily on the availability of materials that exhibit unique properties that are necessary for their development. This paper examines the roles that rare earth and other energy-critical materials play in securing a clean energy economy and the development of clean energy economies in general. For the development of these technologies to be successful and sustainable, a number of these energy-critical materials are at risk of becoming unavailable. This is due to their limited availability, disruptions in supply, and a lack of suitable resources for their development. An action plan focusing on producing energy-critical materials in energy-efficient ways is discussed as part of an initiative to advance the development of clean and sustainable energy.
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Affiliation(s)
- Ram Krishna
- Department of Metallurgical and Materials Engineering, National Institute of Technology Jamshedpur, Jamshedpur, Jharkhand, India.
| | | | - Abhishek Arya
- Department of Metallurgical and Materials Engineering, National Institute of Technology Jamshedpur, Jamshedpur, Jharkhand, India
| | - Ranjit Prasad
- Department of Metallurgical and Materials Engineering, National Institute of Technology Jamshedpur, Jamshedpur, Jharkhand, India
| | - Ilhami Colak
- Department of Electrical and Electronics Engineering, Nisantasi University, Istanbul, Turkey
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3
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Habibzadeh A, Kucuker MA, Gökelma M. Review on the Parameters of Recycling NdFeB Magnets via a Hydrogenation Process. ACS OMEGA 2023; 8:17431-17445. [PMID: 37251130 PMCID: PMC10210235 DOI: 10.1021/acsomega.3c00299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 04/24/2023] [Indexed: 05/31/2023]
Abstract
Regarding the restrictions recently imposed by China on the export of rare-earth elements (REEs), the world may face a serious challenge in supplying some REEs such as neodymium and dysprosium soon. Recycling secondary sources is strongly recommended to mitigate the supply risk of REEs. Hydrogen processing of magnetic scrap (HPMS) as one of the best approaches for magnet-to-magnet recycling is thoroughly reviewed in this study in terms of parameters and properties. The processes of hydrogen decrepitation (HD) and hydrogenation-disproportionation-desorption-recombination (HDDR) are two common methods for HPMS. Employing a hydrogenation process can shorten the production route of new magnets from the discarded magnets compared to other recycling routes such as the hydrometallurgical route. However, determining the optimal pressure and temperature for the process is challenging due to the sensitivity to the initial chemical composition and the interaction of temperature and pressure. Pressure, temperature, initial chemical composition, gas flow rate, particle size distribution, grain size, and oxygen content are the effective parameters for the final magnetic properties. All these influencing parameters are discussed in detail in this review. The recovery rate of magnetic properties has been the concern of most research in this field and can be achieved up to 90% by employing a low hydrogenation temperature and pressure and using additives such as REE hydrides after hydrogenation and before sintering.
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Affiliation(s)
- Alireza Habibzadeh
- Department
of Materials Science and Engineering, Izmir
Institute of Technology, 35430 Izmir, Türkiye
| | - Mehmet Ali Kucuker
- Department
of Environmental Engineering, Izmir Institute
of Technology, 35430 Izmir, Türkiye
| | - Mertol Gökelma
- Department
of Materials Science and Engineering, Izmir
Institute of Technology, 35430 Izmir, Türkiye
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4
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Kumari A, Kumar Sahu S. A comprehensive review on recycling of critical raw materials from spent neodymium iron boron (NdFeB) magnet. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2023.123527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
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5
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Comparison of the Preparation Process of Rare Earth Oxides from the Water Leaching Solution of Waste Nd-Fe-B Magnets’ Sulfate Roasting Products. Processes (Basel) 2022. [DOI: 10.3390/pr10112310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The new process developed here consisting of sulfurization roasting transformation and water immersion can effectively realize the separation of rare earth elements (REEs) and impurities from spent Nd-Fe-B magnets. For the industrial application of the new process, it is critical to determine how to economically and efficiently prepare rare earth oxide (RExOy) products with higher purity from the obtained water leaching solution. Therefore, according to rare earth sulfate (RE2(SO4)3) solution characteristics, the oxalic acid precipitation–calcination method, sodium carbonate precipitation–calcination method, and double sulfates precipitation–alkali conversion–calcination method were optimized and compared. The results show that the recovery efficiency of REE recovery via the oxalic acid precipitation–calcination method is 99.44%, and the purity of RExOy is 99.83% under optimal technological conditions. However, the cost of oxalic acid precipitation is higher. The process consisting of the double sulfates precipitation–alkali conversion–calcination method is relatively complicated, the recovery efficiency of REEs is 97.95%, and the purity of the RExOy is 98.04%. The recovery efficiency of the REEs and the purity of the RExOy obtained from the sodium carbonate precipitation–calcination method are 99.12% and 98.33%, respectively. Moreover, the recycling cost of sodium carbonate precipitation is the lowest among the three processes for preparing RExOy, so it has industrial application potential. The obtained results for REE recovery from spent Nd-Fe-B magnets in this research can provide theoretical guidance for the innovation of the recycling process for REEs as secondary resources.
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6
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Selective extraction and separation of REEs from NdFeB magnets scrap using co-chlorination and water leaching. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.122452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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7
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Wen Z, Chen H, Pan J, Jia R, Yang F, Liu H, Zhang L, Zhang N, Zhou C. Grinding activation effect on the flotation recovery of unburned carbon and leachability of rare earth elements in coal fly ash. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2021.117045] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Ferreira N, Fabre E, Henriques B, Viana T, Costa M, Pinto J, Tavares D, Carvalho L, Pinheiro-Torres J, Pereira E. Response surface approach to optimize the removal of the critical raw material dysprosium from water through living seaweeds. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 300:113697. [PMID: 34543961 DOI: 10.1016/j.jenvman.2021.113697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/29/2021] [Accepted: 09/05/2021] [Indexed: 06/13/2023]
Abstract
Dysprosium (Dy) is a rare earth element with a high economic and strategic value, and simultaneously an emerging contaminant, whose removal from wastewaters is gaining increasing attention. In this work, the Response Surface Methodology (RSM) combined with a Box-Behnken Design (3 factors-3 levels) was used to optimize the key operational conditions that influence the uptake of Dy by two living seaweed, Ulva sp. and Gracilaria sp.. The initial concentration of Dy (10-500 μg/L), water salinity (10-30), and seaweed dosage (0.5-5.5 g/L) were the independent variables, while the removal efficiency (%) and bioaccumulation (q, μg/g) were the response variables. Results highlighted the high capacity of both species to capture Dy. After 168 h, the optimal conditions that led to a maximum of 91 % of Dy removed by Gracilaria sp. were: 500 μg of Dy per L of water, salinity 10, and 5.5 g of seaweed per L. For Ulva sp., a maximum removal percentage of 79 % was achieved in the conditions: any initial concentration of Dy, salinity 20, and seaweed dosage of 3.7 g/L. Independently of the species, the response surfaces showed that the most important variable for the removal is the seaweed dosage, while for bioaccumulation is the initial concentration of Dy. Using RSM, it was possible to obtain the optimal operating conditions for Dy removal from waters, which is a fundamental step toward the application of the proposed technology at large scale.
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Affiliation(s)
- Nicole Ferreira
- LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro, Portugal
| | - Elaine Fabre
- LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro, Portugal
| | - Bruno Henriques
- LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro, Portugal.
| | - Thainara Viana
- LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro, Portugal
| | - Marcelo Costa
- LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro, Portugal
| | - João Pinto
- LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro, Portugal
| | - Daniela Tavares
- LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro, Portugal
| | - Lina Carvalho
- Central Laboratory of Analysis (LCA), University of Aveiro, Aveiro, Portugal
| | | | - Eduarda Pereira
- LAQV-REQUIMTE - Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro, Portugal
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9
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Haider SK, Kim D, Kang YS. Four-step eco-friendly energy efficient recycling of contaminated Nd 2Fe 14B sludge and coercivity enhancement by reducing oxygen content. Sci Rep 2021; 11:22255. [PMID: 34782678 PMCID: PMC8593190 DOI: 10.1038/s41598-021-01382-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
Complete recycling of Nd2Fe14B sludge by chemical methods has gained significance in recent years, however, it is not easy to recycle highly contaminant sludge and obtain product with good magnetic properties. Herein we report a simple four-step process to recycle the Nd2Fe14B sludge containing ~ 10% of contaminants. Sludge was leached in H2SO4 and selectively co-precipitated in two steps. In the first co-precipitation, Al3+ and Cu2+ were removed at pH 6. Thereafter, in the second co-precipitation Fe2+ and RE3+ sulfates were converted to the Fe and RE hydroxides. By annealing at 800 °C RE and Fe hydroxides precipitates were converted to the oxides and residual carbon was oxidized to CO2. After the addition of boric acid, Fe and RE oxides were reduced and diffused to the (Nd-RE)2Fe14B by calciothermic reduction diffusion. Removal of CaO by washing with D.I. water in glove box reduced the oxygen content (~ 0.7%), improved crystallinity and enhanced the magnetic properties significantly. Coercivity increased more than three times (from 242.71 to 800.55 kA/m) and Mr value was also enhanced up to more than 20% (from 0.481 to 0.605 T). In this green process Na2SO4 and Ca(OH)2 were produced as by-product those are non-hazardous and were removed conveniently.
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Affiliation(s)
- Syed Kamran Haider
- Convergence Research Center for Development of Mineral Resources, Korea Institute of Geoscience and Mineral Resources, 124, Gwahakro, Yuseonggu, Daejeon, 34132, Korea.,Powder and Ceramics Division, Korea Institute of Materials Science, 797, Changwondaero, Seongsangu, Changwon, Gyeongnam, 51508, Korea.,Department of Chemistry, Sogang University, 35, Baekbeomro, Mapogu, Seoul, 04107, Korea
| | - Dongsoo Kim
- Convergence Research Center for Development of Mineral Resources, Korea Institute of Geoscience and Mineral Resources, 124, Gwahakro, Yuseonggu, Daejeon, 34132, Korea. .,Powder and Ceramics Division, Korea Institute of Materials Science, 797, Changwondaero, Seongsangu, Changwon, Gyeongnam, 51508, Korea.
| | - Young Soo Kang
- Department of Chemistry, Sogang University, 35, Baekbeomro, Mapogu, Seoul, 04107, Korea.
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10
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Ji B, Zhang W. Rare earth elements (REEs) recovery and porous silica preparation from kaolinite. POWDER TECHNOL 2021. [DOI: 10.1016/j.powtec.2021.06.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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11
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Abstract
The growing production of green technologies (such as electric vehicles and systems for renewable electricity production, e.g., wind turbine) is increasing the rare earth element (REE) demands. These metals are considered critical for Europe for their economic relevance and the supply risk. The end-of-life permanent magnets are considered a potential secondary resource of REEs thanks to their content of neodymium (Nd), praseodymium (Pr) or dysprosium (Dy). The scientific literature reports many techniques for permanent magnet recovery. This work used a life cycle assessment (LCA) to identify the most sustainable choice, suggesting the possible improvements to reduce the environmental load. Three different processes are considered: two hydrometallurgical treatments (the first one with HCl and the other one with solid-state chlorination), and a pyrometallurgical technique. The present paper aims to push the stakeholders towards the implementation of sustainable processes for end-of-life permanent magnet exploitation at industrial scale.
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12
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Freitas R, Cardoso CED, Costa S, Morais T, Moleiro P, Lima AFD, Soares M, Figueiredo S, Águeda TL, Rocha P, Amador G, Soares AMVM, Pereira E. New insights on the impacts of e-waste towards marine bivalves: The case of the rare earth element Dysprosium. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 260:113859. [PMID: 31991344 DOI: 10.1016/j.envpol.2019.113859] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 11/30/2019] [Accepted: 12/19/2019] [Indexed: 06/10/2023]
Abstract
With the technological advances and economic development, the multiplicity and wide variety of applications of electrical and electronic equipment have increased, as well as the amount of end-of-life products (waste of electrical and electronic equipment, WEEE). Accompanying their increasing application, there is an increasing risk to aquatic ecosystems and inhabiting organisms. Among the most common elements present in WEEE are rare earth elements (REE) such as Dysprosium (Dy). The present study evaluated the metabolic and oxidative stress responses of mussels Mytilus galloprovincialis exposed to an increasing range of Dy concentrations, after a 28 days experimental period. The results obtained highlighted that Dy was responsible for mussel's metabolic increase associated with glycogen expenditure, activation of antioxidant and biotransformation defences and cellular damage, with a clear loss of redox balance. Such effects may greatly impact mussel's physiological functions, including reproduction capacity and growth, with implications for population conservation. Overall the present study pointed out the need for more research on the toxic impacts resulting from these emerging pollutants, especially towards marine and estuarine invertebrate species.
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Affiliation(s)
- Rosa Freitas
- Departamento de Biologia & CESAM, Universidade de Aveiro, 3810-193, Aveiro, Portugal.
| | - Celso E D Cardoso
- Departamento de Química & LAQV-REQUIMTE, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Silvana Costa
- Departamento de Biologia & CESAM, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Tiago Morais
- Departamento de Química, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Pedro Moleiro
- Departamento de Química, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - André F D Lima
- Departamento de Química, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Márcio Soares
- Departamento de Química, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Samuel Figueiredo
- Departamento de Química, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Tiago L Águeda
- Departamento de Química, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Pedro Rocha
- Departamento de Química, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Gonçalo Amador
- Departamento de Química, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Amadeu M V M Soares
- Departamento de Biologia & CESAM, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Eduarda Pereira
- Departamento de Química & LAQV-REQUIMTE, Universidade de Aveiro, 3810-193, Aveiro, Portugal
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13
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Recycling of ultrafine NdFeB waste by the selective precipitation of rare earth and the electrodeposition of iron in hydrofluoric acid. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2019.115870] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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14
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Cardoso CED, Almeida JC, Lopes CB, Trindade T, Vale C, Pereira E. Recovery of Rare Earth Elements by Carbon-Based Nanomaterials-A Review. NANOMATERIALS 2019; 9:nano9060814. [PMID: 31146505 PMCID: PMC6630350 DOI: 10.3390/nano9060814] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 05/16/2019] [Accepted: 05/21/2019] [Indexed: 11/16/2022]
Abstract
Modern societies depend strongly on electronic and electric equipment (EEE) which has a side effect result on the large production of electronic wastes (e-waste). This has been regarded as a worldwide issue, because of its environmental impact-namely due to non-adequate treatment and storage limitations. In particular, EEE is dependent on the availability of rare earth elements (REEs), considered as the "vitamins" of modern industry, due to their crucial role in the development of new cutting-edge technologies. High demand and limited resources of REEs in Europe, combined with potential environmental problems, enforce the development of innovative low-cost techniques and materials to recover these elements from e-waste and wastewaters. In this context, sorption methods have shown advantages to pre-concentrate REEs from wastewaters and several studies have reported the use of diverse nanomaterials for these purposes, although mostly describing the sorption of REEs from synthetic and mono-elemental solutions at unrealistic metal concentrations. This review is a one-stop-reference by bringing together recent research works in the scope of the application of carbon nanomaterials for the recovery of REEs from water.
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Affiliation(s)
- Celso E D Cardoso
- Chemistry Department, CICECO and CESAM & LAQV-REQUIMTE, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
| | - Joana C Almeida
- Chemistry Department, CICECO and CESAM & LAQV-REQUIMTE, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
| | - Cláudia B Lopes
- Chemistry Department, CICECO and CESAM & LAQV-REQUIMTE, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
| | - Tito Trindade
- Chemistry Department, CICECO and CESAM & LAQV-REQUIMTE, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
| | - Carlos Vale
- Interdisciplinar Centre of Marine and Environmental Research, 4450-208 Matosinhos, Portugal.
| | - Eduarda Pereira
- Chemistry Department, CICECO and CESAM & LAQV-REQUIMTE, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
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15
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Solvent Extraction and Separation of Nd, Pr and Dy from Leach Liquor of Waste NdFeB Magnet Using the Nitrate Form of Mextral® 336At in the Presence of Aquo-Complexing Agent EDTA. METALS 2019. [DOI: 10.3390/met9020269] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
:Solvent extraction and separation of Pr, Nd and Dy from a synthetic leach solution of spent NdFeB magnet from wind turbines in the presence of aquo-complexing agent Ethylenediaminetetraacetic acid (EDTA) was studied using the nitrate form of Mextral® 336At ([336At][NO3]) as an extractant. The effect of different process parameters such as pH, extractant, nitrate, and EDTA concentrations on the extraction of Pr, Nd and Dy was studied. The extraction of these rare earths elements follows the order Pr > Nd > Dy, whereas EDTA forms stable complexes in the order Dy > Nd > Pr. The synergy of these two effects improved the selectivity among these elements as compared to when no aquo-complexing agent was used. The mechanism of extraction of rare earth elements was established by slope analysis method. The Fourier-Transform Infrared Spectroscopy (FTIR) spectra of [336At][NO3] and extracted Nd complex were recorded to understand the interaction of extractant with rare earth metal ions in the organic phase.
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16
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Kumari A, Sinha MK, Pramanik S, Sahu SK. Recovery of rare earths from spent NdFeB magnets of wind turbine: Leaching and kinetic aspects. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 75:486-498. [PMID: 29397277 DOI: 10.1016/j.wasman.2018.01.033] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/23/2018] [Accepted: 01/23/2018] [Indexed: 05/15/2023]
Abstract
Increasing demands of rare earth (RE) metals for advanced technological applications coupled with the scarcity of primary resources have led to the development of processes to treat secondary resources like scraps or end of life products that are often rich in such metals. Spent NdFeB magnet may serve as a potential source of rare earths containing around ∼30% of neodymium and other rare earths. In the present investigation, a pyro-hydrometallurgical process has been developed to recover rare earth elements (Nd, Pr and Dy) from the spent wind turbine magnet. The spent magnet is demagnetized and roasted at 1123 K to convert rare earths and iron to their respective oxides. Roasting of the magnet not only provides selectivity, but enhances the leaching efficiency also. The leaching of the roasted sample with 0.5 M hydrochloric acid at 368 K, 100 g/L pulp density and 500 rpm for 300 min selectively recovers the rare earth elements almost quantitatively leaving iron oxide in the residue. Leaching of rare earth elements with hydrochloric acid follows the mixed controlled kinetic model with activation energy (Ea) of 30.1 kJ/mol in the temperature range 348-368 K. The leaching mechanism is further established by characterizing the leach residues obtained at different time intervals by scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD). Individual rare earth elements from the leach solution containing 16.8 g/L of Nd, 3.8 g/L Pr, 0.28 g/L of Dy and other minor impurity elements could be separated by solvent extraction. However, mixed rare earth oxide of 99% purity was produced by oxalate precipitation followed by roasting. The leach residue comprising of pure hematite has a potential to be used as pigment or can find other applications.
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Affiliation(s)
- Aarti Kumari
- Metal Extraction and Recycling Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-NML, Jamshedpur 831007, India
| | - Manish Kumar Sinha
- Metal Extraction and Recycling Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007, India
| | - Swati Pramanik
- Metal Extraction and Recycling Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007, India
| | - Sushanta Kumar Sahu
- Metal Extraction and Recycling Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007, India; Academy of Scientific and Innovative Research (AcSIR), CSIR-NML, Jamshedpur 831007, India.
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17
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An environmentally friendly electro-oxidative approach to recover valuable elements from NdFeB magnet waste. Sep Purif Technol 2018. [DOI: 10.1016/j.seppur.2017.09.053] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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