Green Recovery of Rare Earths from Waste Cathode Ray Tube Phosphors: Oxidative Leaching and Kinetic Aspects

Yin, Xiaofei; Wu, Yufeng; Tian, Xiangmiao; Zhang, Yinan; Zuo, Tieyong

doi:10.1021/acssuschemeng.6b01965

Cited by 37 publications

(19 citation statements)

References 27 publications

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“…Therefore, it is often mixed with cheaper yttrium-containing mischmetal or with HREEs. For this reason, magnesium alloys are very interesting from the point of view of consuming the excess of yttrium that will become available from the recycling of lamp phosphors from end-of-life fluorescent lamps [88,[121][122][123][124] and from CRT phosphor waste [88,[125][126][127][128]. It can also be used to consume most of the REEs that are available in excess (La, Ce, Sm, Gd, Ho, Er, Tm), thereby balancing their markets as well.…”

Section: Magnesium and Aluminum Alloys As A Possible Solution To The mentioning

confidence: 99%

Rare Earths and the Balance Problem: How to Deal with Changing Markets?

Binnemans

Jones

Müller

et al. 2018

J. Sustain. Metall.

241

136

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The balance between the market demand and the natural abundance of the rare-earth elements (REEs) in ores, often referred to as the Balance Problem (or the Balancing Problem), is a major issue for REE suppliers. The ideal situation is a perfect match between the market demand for and the production of REEs, so that there are no surpluses of any of the REEs. This means that the rare-earth industry must find new uses for REEs that are available in excess and search for substitutes for REEs that have either limited availability or are high in demand. We present an overview of the trends in the applications for the different REEs and show that the demand for REEs for use in magnets, catalysts, and alloys is still increasing, while the application of REEs in polishing agents, glass, and ceramics are stable. On the other hand, the use of REEs in nickel-metal-hydride (NiMH) batteries and lamp phosphors is decreasing. These changes in the REE market have an influence on the Balance Problem, because the REEs that can be recycled from fluorescent lamps, cathode-ray tubes (CRTs), and NiMH batteries have to be at least partly reused in other applications. Magnesium and aluminum alloys offer an opportunity to mitigate the Balance Problem caused by these changes in the REE market. This is illustrated for REEs that can be recycled from fluorescent-lamp phosphor waste, CRT phosphors, and NiMH batteries. At present, five REEs (Nd, Eu, Tb, Dy, and Y) are being considered as very critical by Europe, the United States, and Japan, but we forecast that in the medium term, only neodymium will remain a critical REE. This paper discusses the relationship between criticality and the Balance Problem and shows how this relationship influences the market for specific REEs.

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Section: Magnesium and Aluminum Alloys As A Possible Solution To The mentioning

confidence: 99%

Rare Earths and the Balance Problem: How to Deal with Changing Markets?

Binnemans

Jones

Müller

et al. 2018

J. Sustain. Metall.

241

136

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“…Fig3 showed the systematic two step leaching process of waste fluorescent powder [10], here it is reported that during 1 st step the leach liquor contains a higher percentage of Y and Eu and 2 nd step leach liquor is reached in Ce and Tb metal. Different researcher studied the differentleaching agent for recycling of REMs such as Eu and Y from CRT waste [24,53,54,55,56,57].…”

Section: Dual Acid Leachingmentioning

confidence: 99%

Recycling of REMS and removal of toxic metals from fluorescent and CRT waste: a review

2020

Biointerface Res Appl Chem

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Fluorescent lamp and cathode ray tube (CRT) waste considered as hazardous waste by commission of European communities and resource conservation and recovery act (RCRA). Due to the presence of mercury and lead in fluorescent waste and cathode ray tube waste, it is highly toxic for environment. Simultaneously, these wastes are also a vital source of different rare earth elements (REEs) such as Y, Eu, Ce, Tb and La. REEs are the most critical resources in the development of both traditional and high-tech industries all over the world. In order to prevent the misuse of natural resources, recycling of REEs from fluorescent and CRT waste is an effective step for accelerating the sustainable use of resources and protect environmental pollution from mining. So, recovery of REEs as well as removal of contaminated hazardous metals such as Hg and Pb from waste is a challenging task. Many researchers in the last few years focused on the development of different process such as solvent extraction, selective leaching, and precipitation for recovery of rare earth elements as well as the removal of toxic metal from waste. Particularly recoveries of yttrium and europium metals are the main interest of many researchers due to huge application in CFL bulbs and CRT tubes. Selective leaching of Y and Eu can be obtained in dilute acid solution with moderate temperature. Dissolution of Pb in leaching process can be avoided by leaching with H2SO4 as it forms insoluble sulfate. While coming to solvent extraction, three major classes of conventional extractantshavebeen used for extraction of REEs such as cation exchanger, solvating extractants and anion exchangers. The use of ionic liquids instead of conventional extractantsismore interesting in modern research because of their high thermal stability, nontoxic and high extraction ability. They are used for effective recovery of REEs from e-waste.

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“…Hydrometallurgical method has some advantages over pyrometallurgical one, such as lower energy consumption, lower toxic gas emission, and more effective leaching of metals . The conventional hydrometallurgical process for REEs recovery uses various types of mineral acids as leaching agents, such as hydrochloric acid (HCl), sulfuric acid (H 2 SO 4 ), and nitric acid (HNO 3 ) . Review literatures of acid extraction of Y and Eu revealed that high temperature, long reaction time, and concentrated acid are needed in leaching …”

Section: Introductionmentioning

confidence: 99%

“…5 The conventional hydrometallurgical process for REEs recovery uses various types of mineral acids as leaching agents, such as hydrochloric acid (HCl), sulfuric acid (H 2 SO 4 ), and nitric acid (HNO 3 ). 6,17,18 Review literatures of acid extraction of Y and Eu revealed that high temperature, long reaction time, and concentrated acid are needed in leaching. [19][20][21] 3860 www.soci.org J Lie, S Ismadji, J-C Liu…”

Section: Introductionmentioning

confidence: 99%

Microwave‐assisted leaching of rare earth elements (Y and Eu) from waste cathode ray tube phosphor

Lie

Ismadji

Liu

2019

J of Chemical Tech & Biotech

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BACKGROUND Phosphor in discarded cathode ray tube (CRT) contained valuable metals, yttrium (Y) and europium (Eu), which are categorized as technology‐critical elements (TCEs) in terms of their supply risk and importance in emerging technologies. Microwave‐assisted leaching was applied to recover Y and Eu from waste CRT with sulfuric acid (H2SO4) solution as the leaching agent in the current study. It is aimed to develop an alternative leaching method of valuable metals from waste CRT phosphor. RESULTS The effects of microwave power and acid concentration on leaching efficiency of Y and Eu were investigated. Shrinking‐core model could describe the leaching kinetics of Y and Eu well and it was controlled by chemical reaction and diffusion through the product layer. Higher leaching efficiency was found when microwave power increased from 200 to 600 W, and was also found as acid concentration increased from 0.5 to 2 mol L−1. Leaching efficiency of Y and Eu were 78.07% and 100%, respectively, for Y and Eu within 60 min at microwave power of 400 W, using 2 mol L−1 of H2SO4 at 10 g L−1 of solid to liquid ratio. Compared with conventional leaching, microwave‐assisted leaching is an alternative technology that could shorten reaction time significantly. CONCLUSIONS The concentration of acid and microwave power affected microwave‐assisted leaching of Y and Eu from waste CRT phosphor. Microwave‐assisted leaching could be an alternative process for rare earth elements recovery. © 2019 Society of Chemical Industry

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Green Recovery of Rare Earths from Waste Cathode Ray Tube Phosphors: Oxidative Leaching and Kinetic Aspects

Cited by 37 publications

References 27 publications

Rare Earths and the Balance Problem: How to Deal with Changing Markets?

Rare Earths and the Balance Problem: How to Deal with Changing Markets?

Recycling of REMS and removal of toxic metals from fluorescent and CRT waste: a review

Microwave‐assisted leaching of rare earth elements (Y and Eu) from waste cathode ray tube phosphor

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