Article
Geochemistry & Geophysics
Harry Watts, Tonya Fisher
Summary: Monazite is a poorly soluble rare earth phosphate mineral that is difficult to break down in industry processes using concentrated sulphuric acid or caustic soda. A new method has been developed for a direct and rapid breakdown of monazite through simple dissolution under milder conditions, avoiding the use of strong acids/bases and reducing the risk of dust exposure from fine grinding particles.
Article
Engineering, Environmental
Ghazaleh Shakiba, Roozbeh Saneie, Hadi Abdollahi, Ehsan Ebrahimi, Ali Rezaei, Mohsen Mohammadkhani
Summary: In this paper, deep eutectic solvents (DESs) were applied as a green replacement for conventional solvents in the leaching process of REEs from monazite. The DES comprised of 2ChCl:1PTSA exhibited the highest extraction efficiency.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Engineering, Environmental
Siiri Peramaki, Antti Tiihonen, Joona Rajahalme, Sylva Larsson, Elmeri Lahtinen, Joni Niskanen, Roshan Budhathoki, Ari Vaisanen
Summary: An efficient leaching process has been developed for extracting nickel, cobalt, and rare earth elements (REEs) from spent nickel metal hydride (NiMH) battery waste. This process involves dry chlorination followed by water leaching, and it has shown high metal recovery rates and environmental friendliness, making it a potential alternative to traditional mineral acid leaching.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2022)
Article
Engineering, Chemical
Wei Liu, Zhongqing Xiao, Subodh Das, Wencai Zhang
Summary: This study conducted direct acid leaching to recover rare earth elements from an allanite ore, and examined the effects of operational variables on the extraction efficiency. The results showed that under certain conditions, the extraction efficiency of rare earth elements was high.
MINERALS ENGINEERING
(2024)
Article
Engineering, Chemical
Bin Ji, Qi Li, Rick Honaker, Wencai Zhang
Summary: The leaching recovery of rare earth elements (REEs) from kaolinite samples was significantly increased by pretreatment through calcination, likely due to the liberation of encapsulated REE-bearing minerals and conversion to more soluble forms. This study also found that the REEs were primarily associated with REE-bearing minerals within kaolinite aggregates, with only a small fraction occurring in an ion-adsorption form. The research suggests that the modes of occurrence and association characteristics of REEs with kaolinite are complex.
MINERALS ENGINEERING
(2022)
Article
Environmental Sciences
Sabrina F. Lutke, Marcos L. S. Oliveira, Samuel R. Waechter, Luis F. O. Silva, Tito R. S. Cadaval, Fabio A. Duarte, Guilherme L. Dotto
Summary: This study investigates the leaching conditions and mechanisms of rare earth elements (REE) from phosphogypsum (PG). Through experimental design and optimization, high leaching efficiency values were obtained using sulfuric acid at a concentration of 2.9 mol L-1, a solid/liquid ratio of 1.7/20 g mL(-1), and a temperature of 55 C. The leaching kinetics results indicated that most REE reached equilibrium in about 20 minutes, and the mechanism investigation suggested that surface chemical reaction and diffusion through the boundary layer controlled the leaching process.
Article
Geochemistry & Geophysics
Vitor L. Gontijo, Leandro Augusto Viana Teixeira, Virginia Sampaio Teixeira Ciminelli
Summary: This work investigates the effect of sulfuric acid baking on the extraction of rare earth elements (REE) from waste rock samples from a phosphate mine. The study highlights the role of different mineralogical assemblages, weathering degree, and the behavior of impurities (iron, phosphorus, and calcium) on REE extraction. The optimal conditions for selective leaching of REE were found to be sulfuric acid baking at 25°C for 15 minutes with an H2SO4:sample (w/w) mass ratio of 0.45:1. Iron-rich samples showed reduced REE extraction and increased iron dissolution with increasing temperature, while higher REE and lower iron extraction were observed with a higher sulfuric acid/sample mass ratio (0.95:1). Calcium-rich samples exhibited lower REE extraction due to the entrapment of REE-bearing minerals by a gypsum layer and the uptake of lanthanides by calcium sulfate compounds formed during leaching.
Article
Engineering, Chemical
Zhang Zhihan, Wang Zhi, Wang Dong, Lin Yong, Xiao Wanhai, Liu Chenghao, Liuyimei Yang, Wu Jian, Li Guobiao
Summary: Rare earth elements (REEs) are crucial for industrial development, and it is important to recycle them from waste containing REEs; however, challenges of high acid consumption and heavy pollution still persist. This study found that the insoluble phase of NdFeO3 significantly inhibited the leaching efficiency of REEs in roasted NdFeB waste. Mechanical activation was an effective method to destroy the structure of the insoluble NdFeO3 phase and increase the leaching efficiency of REEs. This work provides a green strategy and theoretical basis for efficiently recovering REEs from NdFeB waste.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Article
Engineering, Chemical
Iryna Makarava, Aliaksandr Kasach, Dzmitry Kharytonau, Irina Kurilo, Markku Laatikainen, Eveliina Repo
Summary: This study investigates the development of an effective technology for recovering critical rare-earth elements (REEs) from end-of-life permanent magnets. Chemical and electrochemical leaching of NdCeFeB magnets in sulfuric acid with varying concentrations of oxalic acid were examined. It was found that efficient separation of REEs can be achieved at specific concentrations of oxalic acid, and the leaching rate is substantially higher in electrochemical leaching compared to chemical leaching.
MINERALS ENGINEERING
(2022)
Article
Energy & Fuels
Vinoth Kumar Kuppusamy, Maria Holuszko
Summary: The applicability of sulfuric acid baking followed by water leaching (ABWL) for enhancing rare earth element (REE) leaching recovery from coal tailings was investigated in this study. The results showed that ABWL significantly improved REE extraction, reaching around 80% recovery. During the ABWL process, rare earth minerals in the sample were transformed into easily soluble rare earth sulfates.
Article
Engineering, Chemical
Ahmad Nawab, Xinbo Yang, Rick Honaker
Summary: This study introduces a new method for recovering rare earth elements (REEs), especially heavy rare earth elements (HREEs), from coal at lower acid concentrations. Different treatment methods, including roasting and direct acid baking, were investigated and compared. The results showed that direct acid baking at a lower temperature provided the best recovery of both light rare earth elements (LREEs) and HREEs. Roasting followed by acid baking also achieved high recovery rates. The improved recovery was attributed to the dehydroxylation of clay minerals and subsequent release of REE-bearing minerals.
MINERALS ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Bin Ji, Qi Li, Qingqing Huang, Wencai Zhang
Summary: Phosphatic clay, a waste material from phosphate ore beneficiation, was used in this study for rare earth element (REE) recovery. By using HCl extraction and calcination pretreatment methods, the recovery rates were improved. However, increasing the calcination temperature led to reduced recovery rates, likely due to mineral changes.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Nanoscience & Nanotechnology
Congying Wang, Xueqiong Zhang, Jiefei Li, Xingyue Qi, Ziyang Guo, Hang Wei, Haibin Chu
Summary: Layered rare-earth hydroxides (LREHs) were prepared and used to fabricate supported Au catalysts. Among these catalysts, Au/LPrO displayed the best performance in glycerol conversion to lactic acid, highlighting the significant influence of the rare-earth ions on catalytic activities.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Zhili Li, Zhihao Xie, Jie Deng, Dongsheng He, Hengqin Zhao, Huan Liang
Summary: The leaching of rare earth elements from phosphate rock follows a shrinking core model with two distinct stages: a fast reaction stage and a slow reaction stage. The leaching rate in the fast reaction stage is controlled by solid product layer diffusion, while in the slow reaction stage, both solid product layer diffusion and chemical reaction play a role.
Article
Green & Sustainable Science & Technology
Pramesti Prihutami, Agus Prasetya, Wahyudi Budi Sediawan, Himawan Tri Bayu Murti Petrus, Ferian Anggara
Summary: The production of fly ash as a solid waste of coal combustion in Indonesia has been increasing with the growth of electricity demand, posing environmental pollution and health hazards. Utilizing citric acid in leaching experiments on magnetic fly ash revealed a significant temperature-dependent effect on element recovery, following different kinetic models at low and high temperatures.
JOURNAL OF SUSTAINABLE METALLURGY
(2021)
Article
Chemistry, Physical
J. Zamora, T. Bautista, N. S. Portillo-Velez, A. Reyes-Montero, H. Pfeiffer, F. Sanchez-Ochoa, H. A. Lara-Garcia
Summary: Experimental and DFT studies were conducted on the structural, magnetic, and optical properties of RFeO3 perovskites. The perovskites exhibited an orthorhombic crystal structure and weak ferromagnetic behavior. They were confirmed to be semiconductors with a bandgap of approximately 2.1 eV.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Xianxiang Lv, Jing Jin, Weiguang Yang
Summary: By depositing TiN and TiO2 surface layers on AlSi films, the electrochemical performance of silicon-based anodes can be significantly improved, suppressing volume expansion and promoting the formation of a stable SEI layer.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Sharafat Ali, Haider Ali, Syedul Hasnain Bakhtiar, Sajjad Ali, Muhammad Zahid, Ahmed Ismail, Pir Muhammad Ismail, Amir Zada, Imran Khan, Huahai Shen, Rizwan Ullah, Habib Khan, Mohamed Bououdina, Xiaoqiang Wu, Fazal Raziq, Liang Qiao
Summary: The construction and optimization of redox-heterojunctions using a bifunctional phosphate as an electron-bridge demonstrated significant improvements in photo catalytic activity, including enhanced dispersion, reduced interfacial migration resistance, and increased abundance of active-sites.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Ren-Ni Luan, Na Xu, Chao-Ran Li, Zhi-Jie Zhang, Yu-Sheng Zhang, Jun Nan, Shu-Tao Wang, Yong-Ming Chai, Bin Dong
Summary: Extensive research has revealed that oxygen evolution reaction (OER) in alkaline conditions involves dynamic surface restructuring. The development and design of sulfide/oxide pre-catalysts can reasonably adjust the composition and structure after surface reconstruction, which is crucial for OER. This study utilized a simple two-step hydrothermal method to achieve in situ S leaching and doping, inducing the composition change and structure reconstruction of CoFe oxides. The transformed FeOOH and CoOOH exhibited excellent OER activity and could be easily mass-produced using low-cost iron based materials and simple methods.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Jun'an Lai, Daofu Wu, Peng He, Kang An, Yijia Wang, Peng Feng, WeiWei Chen, Zixian Wang, Linfeng Guo, Xiaosheng Tang
Summary: Zero-dimensional organic-inorganic metal halides (OMHs) are gaining attention in the fabrication of light-emitting diodes due to their broad emission band and high photoluminescence quantum yield. This work synthesized a zero-dimensional organic tetraphenylphosphonium bismuth chloride (TBC) that showed efficient blue light emission, with the emission mechanism attributed to the transition of Bi3+ ions. White light-emitting diodes (WLEDs) were fabricated using TBC, along with green-emitting and red-emitting single crystals, achieving single-component white emissions. These findings demonstrate the different emission mechanism of ns2 ions-based OMHs and highlight the potential of bismuth-based OMHs in WLEDs applications.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Xuewei Liang, Yunhai Su, Taisen Yang, Zhiyong Dai, Yingdi Wang, Xingping Yong
Summary: The revolutionary design concept of high-entropy alloys has brought new opportunities and challenges to the development of advanced metal materials. In this work, AlCrCuFe2NiTix high-entropy flux cored wires were prepared by combining the design idea of a high-entropy alloy with the characteristics of flux cored wire. AlCr-CuFe2NiTix high-entropy surfacing alloys were prepared using gas metal arc welding technology. The wear properties of the alloys were analyzed, and the phase composition, microstructure, strengthening mechanism, and wear mechanism were discussed. The results show that the alloys exhibit a dendritic microstructure with BCC/B2 + FCC phases. Increasing Ti content leads to the precipitation of Laves phase. The alloys show improved microhardness and wear resistance due to the precipitation of coherent B2 and Laves phases. However, excessive Ti addition results in the increase of Laves phase and reduced wear resistance of the alloys.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
M. Vadivel, M. Senthil Pandian, P. Ramasamy, Qiang Jing, Bo Liu
Summary: This work presents the enhanced photocatalytic and electrochemical performance of g-C3N4 assisted PAA on CoFe2O4 ternary nanocomposites. The incorporation of PAA and g-C3N4 improves the separation efficiency of photogenerated charge carriers, resulting in superior photocatalytic degradation and high specific capacitance values.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Vibhu T. Sivanandan, Ramany Revathy, Arun S. Prasad
Summary: In this study, pure and doped cobalt ferrite nanoparticles were prepared using the sol-gel auto-combustion method with the aid of lemon juice as eco-fuel. The crystal structure, lattice parameter, crystallite size, microstrain, optical parameters, and room temperature magnetic properties of the samples were analyzed. The effect of doping on the magnetic properties was also investigated.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Qing Guo, Bowen Zhang, Benzhe Sun, Yang Qi
Summary: This study prepared ZnO films with various nonpolar preferred orientations using conventional chemical bath deposition method and characterized their growth process and mechanism. It was found that the type and concentration of nitrate could control the preferred orientation and surface roughness of ZnO films. Additionally, ZnO films with different preferred orientations exhibited different optical properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Chong Zhang, Yan Liu, Zhaoyan Wang, Hang Yang
Summary: In this study, six bimetallic FeCo particles were synthesized via the hydrothermal method at different Fe:Co ratios. The Fe:Co ratio not only modulates the composition of the particles but also influences their structure and magnetic properties. The FeCo alloys showed a transformation from an Fe-based structure to a Co-based structure with increasing Co content. The Fe:Co ratio of 1:1 and 3:1 resulted in particles with the highest and lowest saturation magnetization, respectively.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Jianning Zhang, Jing Li, Yiren Wang, Xiaodong Mao, Yong Jiang
Summary: We conducted a study on the formation of ultra-fine Y-Ti-Ta-O nano-oxides in Ta+B micro-alloyed 13CrWTi-ODS alloys using electron microscopy and first-principles calculations. The Y-Ti-Ta-O nano-oxides were found to be mainly Y2(Ti,Ta)2O7, with an average size of 7 nm and a number density of 6.8 x 1023 m-3. Excess boron was found to enhance the adhesion of some low-sigma grain boundaries but weaken the Fe/Y2Ti2O7 interface, while excess tantalum enhanced the Fe/Y2Ti2O7 interface but caused serious degradation of grain boundaries.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Yirong Fang, Pei Cheng, Hang Yuan, Hao Zhao, Lishu Zhang
Summary: A new composite system of nitrogen-doped reduced graphene oxide and black phosphorus quantum dots has been developed for tumor therapy, showing improved electrochemical properties and stability. The system generates hydrogen peroxide and hydroxyl radical to effectively kill tumor cells.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Xiufang Qin, Yuanli Ma, Hui Zhang, Ting Zhang, Fang Wang, Xiaohong Xu
Summary: The structure and magnetism of cobalt ferrites after Mn2+-Tb3+ co-doping were studied. Co-doped samples exhibited cubic spinel structure and spherical shape of ferrite nanoparticles. The redistribution of Co2+ and Fe3+ ions between octahedral and tetrahedral sites was observed due to Mn2+-Tb3+ co-doping. The coercivity and magnetization saturation of co-doped samples were significantly improved, leading to a maximum energy product that is 190% higher than that of the un-doped sample.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Ho Yeon Lee, Wonjong Yu, Yoon Ho Lee
Summary: Recently, there has been an increasing interest in developing ultra-fine nanostructured electrodes with extensive reaction areas to enhance the performance and low-temperature operation of solid oxide fuel cells. The use of a refined approach involving co-sputtering metal alloys and oxide targets has demonstrated the feasibility of nano-columnar structures in perovskite-based electrodes, expanding the temperature range of thin film electrodes. This study systematically examines the effects of chamber pressure control in the co-sputtering process and identifies the intricate relationship between sputtering pressure and film structure. By fine-tuning the columnar growth in the electrode, significant improvements in performance and thermo-mechanical properties were achieved, resulting in high-performance all-sputtered solid oxide fuel cells.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Physical
Qianyun Bai, Xiaoxiao Yan, Da Liu, Kang Xiang, Xin Tu, Yanhui Guo, Renbing Wu
Summary: This study proposes a simple method to develop a non-precious transition metal-based electrocatalyst with high catalytic activity and robustness for the hydrogen evolution reaction. The as-synthesized electrode exhibits a low overpotential and high current density, indicating its potential in energy conversion.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)