Article
Engineering, Environmental
Patricia Wamea, Mica L. Pitcher, Joy Muthami, Amir Sheikhi
Summary: Rare earth elements are critical in advanced industries, but the world is facing shortages and challenges in sustainable removal. The development of AHNC, a bio-based technology, shows promising results in high-capacity and selective removal of Nd3+ from aqueous media.
CHEMICAL ENGINEERING JOURNAL
(2022)
Review
Metallurgy & Metallurgical Engineering
Yasmim Sagrillo Pimassoni, Maria Tereza Weitzel Dias Carneiro Lima, Luciana Harue Yamane, Renato Ribeiro Siman
Summary: Rare earth elements (REE) are critical metals with high supply risk and growing demand. Waste electrical and electronic equipment (WEEE) is a potential secondary source for recovering REE, but there are challenges and gaps in the recovery process. Hydrometallurgical processes using sulfuric acid have been mainly studied, and sequential processes and recovery from different residues are lacking.
Article
Environmental Studies
Yizhou Li, Yibo Wang, Jianping Ge
Summary: This study adopted a dynamic material flow approach to trace the flows and stocks of dysprosium in China from 2011 to 2020. It revealed the characteristics of dysprosium mining and provided a more realistic estimation of supply and demand balance. The study also addressed the overlooked issue of dysprosium final product recycling. The results showed that dysprosium supply mainly comes from mining, with the largest contribution from Jiangxi Province, accounting for 46% of the total mining amount; from 2011 to 2020, the total dysprosium demand was 132,828 tons, of which 25% was exported; the supply-demand gap was mainly due to dysprosium mining, accounting for approximately 46% of the total supply from 2011 to 2020; and China exhibited a vast dysprosium recycling potential with increasing in-use stocks.
Article
Metallurgy & Metallurgical Engineering
Luver Echeverry-Vargas, Nestor Ricardo Rojas-Reyes, Luz Marina Ocampo-Carmona
Summary: This paper investigates the leaching conditions of hydrochloric acid and sulfuric acid for the maximum extraction of cerium, lanthanum, and neodymium from a dephosphorized monazite concentrate. The experiments showed that sulfuric acid performed better in terms of extraction efficiency. The addition of hydrogen peroxide further enhanced the dissolution of rare earth elements in sulfuric acid. The recovered rare earths can be converted to oxides through precipitation with oxalic acid and subsequent calcination.
Article
Green & Sustainable Science & Technology
Jingxuan Geng, Han Hao, Xin Sun, Dengye Xun, Zongwei Liu, Fuquan Zhao
Summary: This study focuses on conducting a static material flow analysis of neodymium in China to quantitatively analyze the industrial chain structure of neodymium and to calculate the neodymium output from illegal mining. The results show that a considerable amount of primary neodymium resources in China come from illegal mining, emphasizing the importance of recycling neodymium from end-of-life products to reduce illegal mining and meet the increasing demand for neodymium.
JOURNAL OF INDUSTRIAL ECOLOGY
(2021)
Article
Geochemistry & Geophysics
Anna Klemettinen, Andrzej Zak, Ida Chojnacka, Sabina Matuska, Anna Lesniewicz, Maja Welna, Zbigniew Adamski, Lassi Klemettinen, Leszek Rycerz
Summary: A simplified method for leaching rare earth elements from NdFeB magnets was investigated, allowing selective leaching of NdFeB while leaving nickel in a solid state. The use of hydrochloric and sulfuric acids as leaching agents can increase the concentration of rare earth ions in the obtained solutions.
Article
Geochemistry & Geophysics
Anna Klemettinen, Zbigniew Adamski, Anna Lesniewicz, Leszek Rycerz
Summary: Hydrometallurgical methods for NdFeB recycling require a lot of energy, water and chemicals, which hinder their industrial applicability. This study developed a simplified process for rare earth elements (REE) recovery from spent NdFeB magnets and investigated the possibility of regenerating the leaching agent and water. The scaling up of the recycling process was also tested, with promising results in terms of rare earth precipitation efficiency and solution recirculation.
Article
Materials Science, Multidisciplinary
Jayesh Shanthi Bhavan, Jubin Joy, Ashwath Pazhani
Summary: The sustained growth of the electronic and electrical industries emphasizes the importance of efficient energy utilization and recycling of electronic waste. This study aims to identify and explore the recycling possibilities of rare earth materials in electronic waste through material characterization techniques.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Hanwen Chung, Srecko Stopic, Elif Emil-Kaya, Sebahattin Gurmen, Bernd Friedrich
Summary: This paper proposes a pyrometallurgical recycling method for end-of-life NdFeB magnets, achieving the recovery of rare earth elements (REEs) and producing a new concentrate. The metal phase obtained from the smelting process has a high Fe content, while the slag phase contains a mixture of RE-oxides and Fe2O3. The obtained slag concentrate can be further treated to obtain rare earth elements.
Review
Biochemistry & Molecular Biology
Laura Castro, Maria Luisa Blazquez, Felisa Gonzalez, Jesus angel Munoz
Summary: Biohydrometallurgy, a method of recovering metals through microbially mediated processes, has gained attention for extracting critical resources such as rare earth elements. The interest in rare earth elements is growing due to their applications in novel technologies and green economy, with biohydrometallurgy being used to extract resources from waste streams to support innovative mining and promote a circular economy.
Article
Chemistry, Multidisciplinary
Yating Yuan, James Gaugler, Juntian Fan, Bishnu Prasad Thapaliya, Huimin Luo, Abderrahman Atifi, Luis A. Diaz, Sheng Dai
Summary: The electrochemical deposition of rare earth metals at room temperature has gained increasing attention for its energy efficiency advantage over traditional processes. However, the formation of a passivating fluoride layer during electrolyte decomposition is often overlooked, leading to the rapid decay of deposition current and hindering practical application. To address this issue, a fluorine-free electrolyte utilizing borohydride anion was demonstrated, enabling efficient electrodeposition of rare earth metals without passivation effect. Synergetic effects between rare earth borohydride and lithium borohydride were observed, promoting dissociation and improving ionic conductivity and electrochemical performance.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Environmental Sciences
Andrew Turner, John W. Scott, Lee A. Green
Summary: Rare earth elements (REEs) were detected in consumer plastics, likely originating from recycled electronic plastics. Some plastics contained REEs even without detectable flame retardants markers, indicating a more generic source of these elements in consumer plastics.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Geochemistry & Geophysics
Brian A. Haley, Yingzhe Wu, Jesse M. Muratli, Chandranath Basak, Leopoldo D. Pena, Steven L. Goldstein
Summary: Data on dissolved rare earth elements and neodymium isotopes in the Eastern Equatorial Pacific were compared with other data to evaluate current geochemical theories, revealing inconsistencies and suggesting non-conservative components may be at play in the water column.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Review
Geochemistry & Geophysics
Konstantina Pyrgaki, Vasiliki Gemeni, Christos Karkalis, Nikolaos Koukouzas, Petros Koutsovitis, Petros Petrounias
Summary: Mining waste and mine water discharges are potential sources of rare earth elements, but they also contain high concentrations of toxic substances. Different types of ore deposits, ranging from coal to bauxite to phosphate rock, exhibit a wide range of total rare earth element concentrations.
Article
Chemistry, Multidisciplinary
Nighat Afroz Chowdhury, Sidi Deng, Hongyue Jin, Denis Prodius, John W. Sutherland, Ikenna C. Nlebedim
Summary: The paper introduces an innovative technology using copper nitrate to dissolve REEs in NdFeB magnet swarf and recover them with a recovery rate of nearly 97%. The economic and environmental impacts have been quantified, showing the feasibility and benefits of adopting this acid-free dissolution technology for recycling.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2021)
Article
Environmental Sciences
Basudev Swain, Duck-Hee Lee, Chan Gi Lee, Kyung-Soo Park
Summary: The disposal of LED waste involves the recovery of hazardous substances such as arsenic and important metals like gallium, with South Korea focusing on securing a stable supply chain and promoting the concept of urban mining.
WASTE AND BIOMASS VALORIZATION
(2021)
Article
Nanoscience & Nanotechnology
Hyeongsub So, Sung-Jae Won, Jihoon Park, Soong Ju Oh, Leeseung Kang, Kyou-Hyun Kim
Summary: This study investigated the effect of different CuxMgx/10 content in Al-Cu-Mg-based alloys, with Cu6.0Mg0.60 alloy showing the highest mechanical properties. The amount of CuxMgx/10 solutes influences the macroscopic and microscopic structures of the fabricated alloys, with higher content leading to grain size refinement and accelerated formation of theta' strengthening phase. Additionally, a higher content of CuxMgx/10 induces significant microscopic structural distortion, impacting the tensile properties of the developed alloys.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Min-Jung Park, Hyeongsub So, Kyou-Hyun Kim, Jai-Won Byeon, Leeseung Kang
Summary: The natural aging response of the Al-20Zn-3Cu alloy shows a significant increase in ultimate tensile strength up to 12 months, mainly induced by the diffusion of Zn element. The decrease in volume fraction of eutectoid lamellae at the early stage of natural aging leads to an increase in tensile strength, followed by the enhancement of nanoprecipitates growth rate by clusters of solute atoms formed by Zn diffusion into the Al matrix after 9 months.
Article
Materials Science, Multidisciplinary
Jieun Lee, Basudev Swain, Bon Woo Gu, Chan-Gi Lee, Jin-Ho Yoon
Summary: The study has successfully developed a method for extracting and recovering metal values from semiconductor industry tantalum scrap through a combination of hydrometallurgy and pyrometallurgy techniques, including understanding of thermochemistry, determination of suitable oxidation conditions, and effective leaching methods.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2021)
Article
Green & Sustainable Science & Technology
Basudev Swain, Jae Ryang Park, Chan Gi Lee
Summary: The concern for environmental impact of end-of-life vehicles and strict environmental regulations have led to the development of recycling processes for different components such as metal, plastic, glass, and rubber. In this study, an industrial-scale recycling process for end-of-life vehicle windshield glass was developed to recover polyvinyl butyral and glass components. The process involves size reduction and separation of constituent materials, achieving high recovery efficiency for both polyvinyl butyral and glass.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Materials Science, Multidisciplinary
Hyeongsub So, Jae-Hong Shin, Leeseung Kang, Chanuk Jeong, Kyou-Hyun Kim
Summary: The effect of solution temperature (T-sol. = 440-530 degrees C) on the mechanical properties of Al-3.4Cu-0.34Mg-0.3Mn-0.17Ag alloy was investigated. It was found that the alloy showed the highest mechanical strength of sigma(UTS) = ~329 MPa at a T-sol. value of 470 degrees C. The microstructural investigation revealed that the different mechanical properties at different T-sol. values were attributed to grain growth, precipitation hardening, and the formation of large particles at the grain boundaries. The relationships between the microstructural evolution and the mechanical properties were explored with respect to different values of T-sol.
Article
Materials Science, Multidisciplinary
Basudev Swain
Summary: Rare earth metals (REMs) play a critical role in strategic applications such as consumer electronics and clean energy. However, the REM supply chain heavily relies on primary resources, while secondary resources like red mud (RM) containing REMs remain largely unexplored. The current research shows a significant amount of REM oxide in RM, indicating the potential to unlock this resource through efficient technology and research, transforming the supply chain bottleneck into an abundant source.
Article
Engineering, Environmental
Basudev Swain, Jieun Lee, Bon Woo Gu, Chan-Gi Lee, Jin-Ho Yoon
Summary: Global production of tantalum is unable to meet the increasing demand from the electronics industry, with the majority being supplied by Congo and Rwanda. To address this issue, the development of secondary resources and improvement of recycling technologies can provide a solution.
Article
Geosciences, Multidisciplinary
Basudev Swain, Kadambini Sarangi, Jay Ryang Park, Chan Gi Lee
Summary: The Debye-Huckel and Bronsted-Bjerrum theory were applied to study the effect of ionic strength on the separation factor in supported liquid membrane process for Cu(II) and Zn(lI) using D2EHPA as a mobile carrier. A mathematical model based on the two theories was developed and experimental results showed good agreement with calculated values.
GEOSYSTEM ENGINEERING
(2022)
Article
Geosciences, Multidisciplinary
Basudev Swain, Jae-Chun Lee
Summary: This paper discusses the separation of platinum and palladium from chloride solutions using liquid-liquid extraction with Alamine 308 as the extractant. The study evaluates the effects of different process parameters on the separation behavior, such as the concentrations of HCl, NaCl, platinum, and palladium in the aqueous solution, and the concentration of Alamine 308 in the organic phase. Selective stripping of platinum and palladium was achieved using NaSCN and (NH2)(2)CS respectively. The process ensures the separation and recovery of platinum and palladium with 99.99% purity from a mixed solution.
GEOSYSTEM ENGINEERING
(2022)
Review
Biotechnology & Applied Microbiology
Basudev Swain
Summary: Progressive integration of rare earth metals (REMs) in modern technologies and the critical supply chain bottleneck for REM production from primary mineral resources make the recovery of REMs from anthropogenic waste significant and promising. This review analyzes the importance of anthropogenic waste for REM recovery, recycling technologies for sustainable valorization of REMs, and the associated challenges and opportunities. Various anthropogenic wastes, such as spent magnets, batteries, phosphors, red mud, slag, and coal byproducts, contain a significant amount of REMs that can be circularized through valorization technologies. However, industrial-scale valorization processes, clear strategies, roadmaps, policies, efforts, funding, and diversified research are lacking, posing challenges to efficient REM recovery.
REVIEWS IN ENVIRONMENTAL SCIENCE AND BIO-TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Sung-Jae Won, Hyeongsub So, Jung-Woo Han, Soong Ju Oh, Leeseung Kang, Kyou-Hyun Kim
Summary: We demonstrate the effects of Sc and Be microalloying on the mechanical properties of Al-Zn-Mg-Cu-based alloys through comprehensive microstructural investigation. Sc microalloying enhances the tensile properties of an Al-9.0Zn-3.0Mg-3.0Cu alloy, while simultaneous microalloying with Sc and Be reduces the mechanical strength of a synthesized Al alloy. The microstructural investigation reveals that Sc microalloying leads to Al grain refinement, the formation of hardening phases, and an increase in the solid solution of Al.
Article
Environmental Sciences
Jae Ryang Park, Chan Gi Lee, Basudev Swain
Summary: Currently, more than 55% of global indium production is consumed for indium tin oxide (ITO) production driven by the demand for flat panel displays (FPDs) or LCDs. Waste LCDs, accounting for 12.5% of global e-waste, pose a threat to the environment. Recycling waste LCDs for indium recovery is a potential solution, and a bench-scale process for beneficiation and classification of ITO concentrate has been investigated.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Review
Environmental Sciences
Basudev Swain, Ata Akcil, Jae-chun Lee
Summary: Significantly unexploited red mud contains valuable rare earth metals and other metals that can be recovered through an industrial-scale valorization process. The global red mud inventory could reach 4 billion tons by 2020, with a potential value of approximately $4.3 trillion in rare earth metals. This article discusses the challenges and opportunities of valorizing red mud and proposes a feasible sequential metal recovery process.
CRITICAL REVIEWS IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY
(2022)
Proceedings Paper
Metallurgy & Metallurgical Engineering
Basudev Swain, Jae Ryang Park, Kyung Soo Park, Chan-Gi Lee, Hyun Seon Hong, Jae-chun Lee
Summary: In this study, industrial-scale indium recovery from various e-waste resources like waste LCD, LED, and LCD industry etching wastewater has been achieved through the development and integration of processes. A demonstration plant has been established for indium recovery, with almost complete recovery of indium. The integration of different processes can help address pressing issues in the semiconductor manufacturing industry and ITO industry, such as waste disposal, indium recovery, and circular economy.
RARE METAL TECHNOLOGY 2021
(2021)
Article
Engineering, Environmental
Xiaojian Liu, Bei Wang, Yayun Ma, Xiangyang Zhou, Juan Yang, Yuehui He, Jingjing Tang, Fanyun Su, Wan Yang
Summary: This study proposes a combined process of reduction roasting of herb-medicine residue and oxalic acid leaching to improve the recovery efficiency of lithium from spent lithium-ion batteries. By utilizing the reducing gas produced from the pyrolysis of herb-medicine residue, the layered structure of the cathode powder is destroyed and converted into Li2CO3, Ni, Co, and MnO. Additionally, selective extraction of lithium is achieved using oxalic acid, and the efficiency and kinetics of lithium extraction are improved under the combined action of herb-medicine residue and oxalic acid.
Article
Engineering, Environmental
Muxina Konarova, Nuno Batalha, Gabriel Fraga, Mohamed H. M. Ahmed, Steven Pratt, Bronwyn Laycock
Summary: This study presents a proof of concept for a technology that integrates PET recovery from mixed plastic waste and plastic pyrolysis. By depolymerizing PET into TPA using a low volatility oil as medium, it achieves low-pressure operation and a selective separation and recovery of TPA from the product mix. Full PET conversion and high TPA recovery were achieved, making it an effective solution for processing mixed waste streams and improving the yield and quality of liquid product from thermal pyrolysis compared to untreated feedstock.
Article
Engineering, Environmental
Zhenhua Sun, Jing Li, Xuejiang Wang, Siqing Xia, Jianfu Zhao
Summary: This study investigated the influence of in-situ formed MgFe2O4 on the hydrothermal treatment of swine manure. The results showed that the in-situ formation of MgFe2O4 improved the dehydration and decarboxylation of organic components in swine manure, thereby improving its carbonization degree. Furthermore, it enhanced the stabilization of heavy metals and the retention of phosphorus. MgFe2O4 modified hydrochars exhibited remarkable adsorption capacity for Pb(II) and Cu(II) without any leaching of heavy metals.
Article
Engineering, Environmental
Yijing Jiang, Boyang Leng, Jingxin Xi
Summary: The increased generation of municipal solid waste has had a significant impact on the economy, environment, and public health. The current waste treatment process has limitations. By developing a comprehensive social costing model, this study assesses the impacts of municipal solid waste management throughout its life cycle and provides policymakers with best practices and feasibility information.
Article
Engineering, Environmental
Marina Hernandes de Paula e Silva, Ricardo Coser Mergulha, Jose Geraldo Vidal Vieira, Andrea Brasco Pampanelli, Rodrigo Salvador, Diogo Aparecido Lopes Silva
Summary: This study developed and implemented a self-assessment tool to assist companies in decision-making processes for establishing circular flows based on Lean Manufacturing and Circular Economy principles. The tool utilized a maturity model and was applied to nine companies of varying characteristics. The findings revealed that certain companies showed higher maturity in water-waste and chemical-emissions management, with larger enterprises focusing on these strategies. However, many companies lacked sufficient training and employee awareness prior to seeking cleaner alternatives, and comprehensive actions to manage the product lifecycle were lacking. To address these gaps, the tool provided tailored recommendations for each company to improve their processes, products, and value chain.
Article
Engineering, Environmental
Gamze Dogdu, Turgay Pekdemir, Sanaz Lakestani, Seyda Karabork, Osman Cavus
Summary: This paper presents data on food waste associated with mini size food packaging services, highlighting the difficulties in emptying the food and consumer wastefulness as the main causes. These findings have significant implications for the sustainability of food and relevant packaging.
Article
Engineering, Environmental
Qingxia Li, Xin Kong, Yuxin Chen, Jianan Niu, Jia Jing, Jin Yuan, Yifeng Zhang
Summary: This study investigates how to enhance methane production from food waste after hydrothermal pretreatment. The results demonstrate a significant increase in methane yield when zero-valent iron and magnetite are used together, and high organic loading is favorable for methane production. Microbial diversity analysis further reveals the dominant pathways and metabolic processes involved in methane generation.
Article
Engineering, Environmental
D. H. H. Sim, I. A. W. Tan, L. L. P. Lim, E. T. Lau, B. H. Hameed
Summary: The development of controlled-release fertilizer formulation is important for preventing environmental pollution caused by nutrient leaching and volatilization. This study combined biochar-based fertilizer with encapsulation technology to improve the nutrient release mechanism. Optimal conditions for synthesizing urea-impregnated biochar (UIB) were determined using central composite design, and the release of nitrogen was described by mathematical models. Results showed that encapsulated UIB (EUIB) achieved complete release of nitrogen in water and exhibited improved water retention in sandy-textural soil. Therefore, EUIB derived from peppercorn waste has the potential to be used as a sustainable controlled-release fertilizer for agriculture.
Article
Engineering, Environmental
Yuchuan Wang, Neslihan Akdeniz
Summary: Incorporating biochar into composting systems can increase compost temperatures. This study developed a heat transfer model for a biochar-amended co-composting system and found that biochar increased thermal conductive losses but also enhanced microbial activity, resulting in an overall increase in total heat unit. When biochar was applied on the surface, it mainly functioned as an insulator.
Article
Engineering, Environmental
George Tsalis, Birger Boutrup Jensen, Jessica Aschemann-Witzel
Summary: This paper empirically explores the relationship between retail price promotions and household food waste. The results show that households with a higher proportion of discount food purchases and environmental awareness tend to waste less food, while larger households and those lacking food handling skills tend to waste more food.
Article
Engineering, Environmental
Lukas Friederici, Arne Koch, Patrick Martens, Jana Pantzke, Sebastiano Di Bucchianico, Thorsten Streibel, Christopher P. Rueger, Ralf Zimmermann
Summary: The increasing demand for lightweight materials has led to a rise in fiber-reinforced plastic (FRP) production. However, the properties and compositional range of FRPs pose challenges to recycling strategies. Pyrolysis has emerged as a promising method for separating the fibers from the polymer matrix. This study investigated the pyrolysis process using thermal analysis and high-resolution mass spectrometry, and also assessed the toxicity of the recovered fibers using an in vitro model.
Review
Engineering, Environmental
Devika Kannan, Shakiba Khademolqorani, Nassibeh Janatyan, Somaieh Alavi
Summary: This paper introduces Smart Waste Management (SWM) that applies Industry 4.0 technologies in waste management. A framework called SWM4.0 is developed, which highlights the importance of smart people, smart cities, smart enterprises, and smart factories in achieving successful waste management. The paper also suggests future research directions and managerial implications.