Article
Chemistry, Multidisciplinary
Aditya Ranjan Ray, Sujata Mishra
Summary: Modern scientific progress has made rare earth elements more important due to their specific chemical and physical properties. Proper handling and recovery of valuable products like rare earths will address environmental and societal issues caused by mining and industrial waste.
SUSTAINABLE CHEMISTRY AND PHARMACY
(2023)
Article
Green & Sustainable Science & Technology
Sara Ait Hak, Anasse Sraidi, Khaoula Khaless, Rachid Benhida
Summary: Phosphogypsum (PG), a primary by-product of wet process phosphoric acid production, presents challenges to the fertilizer industry. This study explores the leaching of rare earth elements (REEs) from PG and establishes a strong correlation between REEs concentration and leaching efficiency. Nitric acid and hydrochloric acid are effective leaching agents, with calcium sulfate solubility playing a pivotal role. Kinetics investigations indicate that the diffusion of REEs through the product layer is the rate-controlling step.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Engineering, Environmental
Chenna Rao Borra, Thijs J. H. Vlugt, Yongxiang Yang, Jeroen Spooren, Peter Nielsen, Murugaiyan Amirthalingam, S. Erik Offerman
Summary: This study successfully recovered rare earth oxides from waste polishing materials to produce high-value Al-La-Ce alloys. The development of new alloys through novel processes helps utilize both overproduced primary rare earth oxides and those recovered from waste materials.
RESOURCES CONSERVATION AND RECYCLING
(2021)
Review
Geochemistry & Geophysics
Jean-Luc Mukaba, Chuks Paul Eze, Omoniyi Pereao, Leslie Felicia Petrik
Summary: The demand for rare earth elements in high tech electrical and electronic materials is crucial, but the natural deposits are limited globally, prompting the search for alternative resources. Utilizing hydrometallurgical processes to extract REEs from scrap and waste materials is sustainable and feasible, offering low energy consumption, minimal waste generation, and environmentally friendly benefits. The concentration of REEs in industrial waste such as phosphogypsum is low, making the recovery process challenging, but methods like recrystallization show promising advantages for achieving high REE recovery.
Article
Geology
Zeyang Zhang, Yuhang Jiang, Hecai Niu, Jieqi Xing, Shuang Yan, Ao Li, Qiang Weng, Xiaochen Zhao
Summary: The Zhijin phosphorite deposit is a giant rare earth element deposit from the early Cambrian period, primarily enriched in heavy REEs and contained in apatite. Petrographic observations and microscopic analysis reveal that the francolite grains are composed of nano-apatite crystals, capturing abundant REEs during early diagenesis.
ORE GEOLOGY REVIEWS
(2021)
Article
Geology
Haiying Yang, Zhifang Zhao, Xiaomin Cao, Haifeng Fan, Jiafei Xiao, Yong Xia, Min Zeng
Summary: Based on the early Cambrian REY-rich phosphorite from Zhijin, South China, this study analyzed the characteristics of apatite individuals. It was found that terrigenous clastic apatites have the highest REY levels, while authigenic/diagenetic apatites exhibit higher REY concentrations.
ORE GEOLOGY REVIEWS
(2022)
Article
Environmental Sciences
M. Hermassi, M. Granados, C. Valderrama, C. Ayora, J. L. Cortina
Summary: The study successfully developed a three-stage process to selectively separate and concentrate rare earth elements from other metals, producing a product rich in rare earth elements.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Review
Engineering, Chemical
Guilhem Arrachart, Julien Couturier, Sandrine Dourdain, Clement Levard, Stephane Pellet-Rostaing
Summary: Rare earth elements play crucial roles in advanced technologies, making the development of optimized processes for their recovery necessary. Ionic solvents, including ionic liquids and deep-eutectic solvents, have attracted much attention as an alternative to conventional processes for metal recovery. Significant studies in the last decade regarding the recovery of REEs are presented in this review.
Article
Engineering, Chemical
Houqing Wang, Jinliang Wang, Xiang Lei, Xiaochun Wen, Dewei Li, Fupeng Liu, Wenyue Zhou, Shengming Xu
Summary: In this study, a flash furnace was used to explore the low-temperature reduction behavior of NdFeB magnet scraps. A two-step magnetic separation process was employed to separate metallic Fe and REOs from the reduction product.
Article
Metallurgy & Metallurgical Engineering
Ram Karan, T. Sreenivas, M. Ajay Kumar, D. K. Singh
Summary: This paper presents a study on the applicability of deep eutectic solvents (DES) for the recovery of rare earth elements (REE) from coal flyash. The DES systems showed better leaching performance and higher leach recovery compared to individual hydrogen bond donors and acceptors. The leaching mechanism of REE with DES was proposed.
Article
Engineering, Chemical
Ali Dawood Salman, Tatjana Juzsakova, Akos Redey, Phuoc-Cuong Le, X. Cuong Nguyen, Endre Domokos, Thamer A. Abdullah, Veronika Vagvolgyi, S. Woong Chang, D. Duc Nguyen
Summary: The study aims to develop and improve technological steps to recover rare earth elements (REEs) from red mud, combining hydrometallurgical steps such as acid digestion, ion exchange, and solvent extraction. Various parameters were investigated to achieve optimum REE recovery from red mud.
CHEMICAL ENGINEERING & TECHNOLOGY
(2021)
Review
Materials Science, Multidisciplinary
Aleksandra Rybak, Aurelia Rybak
Summary: This article discusses the issues related to recovering rare earth elements from coal fly ashes, emphasizing the increasing demand and wide range of applications for these elements. Various methods are proposed to improve the efficiency of REE recovery, including traditional methods like physical and acid-base leaching, as well as novel techniques such as membrane separation and biological methods.
Article
Engineering, Environmental
Gyoung G. Jang, Austin Ladshaw, Jong K. Keum, Joshua A. Thompson, Patrick Zhang, Costas Tsouris
Summary: The recovery of rare earth elements (REEs) from industrial and natural streams, such as phosphoric acid sludge, is gaining attention to meet manufacturing industry demands. Phosphoric acid sludge is economically feasible for REE recovery due to its concentrated REE content and valuable phosphoric acid. However, the high viscosity and solids content of the sludge require multistep separation and purification processes. This study used a single-step continuous-flow decanter centrifuge (CFDC) to successfully separate solid and liquid components, achieving high liquid recovery and REE-containing solids recovery.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Applied
Hao Wu, Huashan Yan, Yanzhen Liang, Sen Qiu, Xiaowen Zhou, Dongmei Zhu, Tingsheng Qiu
Summary: This study investigates the transformation mechanism of fluorinated rare earth molten-salt electrolytic slag roasted with sodium carbonate and the regulation mechanism of rare earth leaching under different roasting conditions. The experimental results show that increasing temperature, time, hydrochloric acid concentration, and liquid-solid ratio can effectively promote rare earth recovery, and the optimal conditions have been determined. Under these conditions, rare earths can be biologically transformed at a lower temperature, and the leaching efficiency of rare earths exceeds 98%.
JOURNAL OF RARE EARTHS
(2023)
Review
Engineering, Environmental
Xilin Geng, Ying Liu, Wei Zhang, Liangshi Wang, Jiankang Wen, Jianzhi Sun
Summary: Germanium, with its excellent electrical and optical properties, plays a crucial role in various high-tech fields. However, the recovery efficiency of germanium is low, accompanied by high energy consumption and impurities. Therefore, there is an urgent need for efficient and low-consumption green processes to utilize germanium in zinc concentrate. This paper provides a systematic overview of the basic properties, key technologies, and recent advances in leaching and separation of germanium, focusing on the study of germanium species and coordination reactions.
CHEMICAL ENGINEERING JOURNAL
(2022)