This article briefly reviews the major research progress of 9 typical material fields,including rare earth luminescence materials,catalysis,rare earth materials for biomedical applications,magnetic materials,optical crystals,molecular-based materials,energy materials,metals and alloys,as well as rare earth extraction,separation and recycling in the year 2024.The aim of the review is to summarize the past and look into the future,and it will provide a basic overview of domestic work in related fields last year.Due to the abundance of content,the review strives to be concise.
The magneto-optical response of chiral materials holds significant potential for applications in physics, chemistry, and biology. However, exploration of the near-infrared (NIR) magneto-optical response remains limited. Herein, we report the synthesis and strong NIR-II magneto-optical activity of three pairs of chiral 3d-4f clusters of R/S-Ln(15)Cu(54) (Ln = Sm, Gd, and Dy). Structural analysis reveals that R/S-Ln(15)Cu(54) features a triangular prism cage with C-3 symmetry. Interestingly, magnetic circular dichroism (MCD) spectra exhibit remarkable magneto-optical response in the NIR-II region, driven by the f-f transition. The maximum g-factor of R/S-Sm15Cu54 reaches 5.5 x 10(-3) T-1 around 1300-1450 nm, surpassing values associated with Dy-III and Cu-II ions. This remarkable NIR-II magneto-optical activity may be attributed to strong magnetic-dipole-allowed f-f transitions and helix chirality of the structure. This work not only presents the largest Ln-Cu clusters to date but also demonstrate the key role of magnetic-dipole-allowed transitions on magneto-optical activity.
Critical metals in coal-based byproducts have been gradually regarded as one of the most important alternative resources due to the market parameters, strategic perspective, and advanced technology. In this study, the mechanism of calcination-acid leaching for rare earth elements (REY) recovery from coal gangue of Jungar coalfield was proposed based on the results of sample characteristics, extraction law, kinetic analysis, and typical mineral leaching. The micro-particles of bastnaesite and monazite were found and embedded in the kaolinite via micro-observation with SEM-EDS. Kaolinite in coal gangue calcined at 600 ℃ was transformed into highly positively reactive metakaolinite, enhancing the dissolution of aluminum (Al) and exposing the rare earth minerals encapsulated within the particles. Meanwhile, bastnaesite was thermally decomposed into rare earth oxides and rare earth fluorides. Rare earth oxides are more easily dissolved by acid, and the fluoride ions and the aluminum ions form a stable complex ion [AlF6]3-, which promotes the dissolution of rare earth fluoride. In addition, a high REY and Al recovery (78.8% of REY, and 88.5% of Al), came true from calcined coal gangue at optimal conditions. The leaching kinetics showed that REY leaching followed the hybrid control model of interfacial transfer and diffusion through solid layer, while Al leaching is controlled by chemical reaction. The leaching test of bastnaesite and monazite shows that the leaching efficiency of LREY is higher than that of HREY in coal gangue, which is controlled by monazite. This may be related to the crystal structure and the radius of trivalent rare earth ions. This study provides a useful reference for the extraction of REY from coal gangue.
Nanomaterials with unique emission in the second near-infrared window(NIR-Ⅱ,1000 nm-1700 nm)are regarded as the promising probes for visualization of tumor vessels and cerebrovascular architecture,because of their superior features such as deep tissue penetration and large imaging resolution.
Polymer waveguide devices have attracted increasing interest in several rapidly developing areas of broadband communications since they are easily adaptable to on-chip integration and promise low propagation losses. As a key member of the waveguide gain medium, lanthanide doped nanoparticles have been intensively studied to improve the downconversion luminescence. However, current research efforts are almost confined to erbium-doped nanoparticles and amplifiers operating at the C-band; boosting the downconversion luminescence of Tm3+ for S-band optical amplification still remains a challenge. Here we report a Tb3+-induced deactivation control to enhance Tm3+ downconversion luminescence in a stoichiometric Yb lattice without suffering from concentration quenching. We also demonstrate their potential application in an S-band waveguide amplifier and record a maximum optical gain of 18 dB at 1464 nm. Our findings provide valuable insights into the fundamental understanding of deactivation-controlled luminescence enhancement and open up a new avenue toward the development of an S-band polymer waveguide amplifier with high gain.
Whereas the genesis of carbonatitic rare earth element (REE) deposits has long been a focus of study, the controls on mobilization and mineralization of REEs during magmatic-hydrothermal processes still remain open to debate. Here, we present our investigation of the dissolution and crystallization of REE (fluor)carbonate minerals in alkaline carbonate brine-melts up to 850°C and 11.6 kbar. Our results show that REEs are soluble in Na 2 CO 3 brine-melts, achieving concentrations exceeding 8 weight % at temperatures above 650°C. The addition of calcium and/or fluoride has minimal impact on REE mobilization, whereas introduction of silica suppresses REE solubilities by half, due to britholite formation above 550°C. Upon cooling, sodium and REEs combine to crystallize in burbankite or carbocernaite in sodium-enriched brine-melts, even at fluoride saturation. However, while the brine-melts contain substantial ferro- or aluminosilicate, REE mineralization in fluorcarbonates occurs after sufficient sodium precipitation in alkaline silicate minerals, hence revealing how silicate and sodium carbonate govern REE mineralization.
We reported on the spectral properties and dual-wavelength laser performances of a novel, to the best of our knowledge, Nd:Gd1.8Y1.2ScAl4O12 (Nd:GYSAG) crystal for the first time. The absorption spectra, emission spectra, and fluorescence lifetime were systematically investigated. Further, a continuous-wavelength (CW) laser output power up to 5.02 W was obtained under an absorbed pump power of 9.45 W with slope and optical-to-optical efficiencies of 59.4% and 53.1%, respectively, at 1061.2 and 1063.2 nm. A stable passively Q-switched (PQS) laser employing Cr:YAG as a saturable absorber (SA) was realized. The maximum average output power of 0.756 W with a slope of near 34.4% was obtained with the pulse width, pulse energy, and peak power of 14.0 ns, 128.1 µJ, and 9.15 kW, respectively. The results indicate that the Nd:GYSAG crystal is an excellent laser medium for generating a high-efficiency dual-wavelength laser and has potential in terahertz (THz) laser generation.
This paper proposes a method for the short-process recovery and reuse of rare earth secondary resources. Low-value rare earth polishing powder waste (WP), trichromatic phosphor waste (WT), NdFeB permanent magnetic waste (WN), and SmCo permanent magnetic waste (WS) were used as the raw materials. Based on the concept of combinatorial chemistry, energy-efficient cool pigments and environmental remediation materials were synthesized by a solid-phase method. The results showed that the synthesized materials had fluorite-type and garnet-type structures. In terms of cool pigments, doping with different rare earth permanent magnets can enrich the color (including yellow, green, brown, gray, and blue) and cause fluctuations in the near-infrared (NIR) reflectance (59.05-99.54%) and NIR solar reflectance (55.32-95.64%). Yellow fluorite-type pigments (WP: WT=1:1) have the highest NIR reflectance (R=99.54%), while brown fluorite-type pigments (WP: WN=1:0.1) and blue garnet-type pigments (WP:WS=1:0.1) have relatively high NIR reflectance, 88.18% and 59.30%, respectively. The synthesized pigments possessed better chemical stabilities and thermal insulation performance. In terms of environmental remediation materials, the adsorption capacities of fluorite-type materials for F- and PO43- can reach 84.03 mg/g and 85.3 mg/g, respectively. In summary, materials synthesized from rare earth waste exhibit excellent potential for use in energy-efficient wastewater treatment and promote the sustainable utilization of secondary rare earth resources.
This paper presents a novel rare earth-based chromate (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)CrO3 for high-temperature thermistor applications. X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy tests reveal that the material is a high-entropy ceramic with a perovskite structure, exhibiting a dense microstructure with a relative density of 97.6%. Electrical analysis shows that (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)CrO3 exhibits high resistivity at high temperatures but with a material constant of 1,968 K, making it capable of meeting the resistance requirements for commercial thermistors over an ultrawide temperature range of 25 – 1,300 °C. AIMD simulations indicate the excellent structural stability of (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)CrO3 even at 1,300 °C, suggesting promising high-temperature aging characteristics. Further aging tests demonstrate that its resistance only drifted by 4.57% after being subjected to 1,300 °C for 1,000 h. The above findings represent breakthroughs in terms of maximum operating temperature, applicable temperature range, aging performance and sintering densification for chromate-based high-temperature thermistor ceramics.
Bioleaching is considered an alternative to traditional rare earth extraction technology. However, since rare earth elements exist as complexes in bioleaching lixivium, they cannot be directly precipitated by normal precipitants, which restricts their further development. This structurally stable complex is also a common challenge in various types of industrial wastewater treatment. In this work, a new method called a three-step precipitation process is first proposed to efficiently recover rare earth-citrate (RE-Cit) complexes from (bio)leaching lixivium. It consists of coordinate bond activation (carboxylation by pH adjustment), structure transformation (Ca2+ addition) and carbonate precipitation (soluble CO32- addition). The optimization conditions are determined to adjust the lixivium pH to around 2.0, then add calcium carbonate until the n(Ca2+): n(Cit3-) is more than 1.4:1 and lastly add sodium carbonate until n(CO32-): n(RE3+) is more than 4:1. The results of precipitation experiments using imitated lixivium show that the rare earth yield is more than 96% and the impurity aluminum yield is less than 20%. Subsequently, pilot tests (1000 L) using real lixivium were successfully conducted. The precipitation mechanism is briefly discussed and proposed by thermogravimetric analysis, Fourier infrared spectroscopy, Raman spectroscopy and UV spectroscopy. This technology is promising in the industrial application of rare earth (bio)hydrometallurgy and wastewater treatment due to its advantages of high efficiency, low cost, environmental friendliness and simple operation.
As yet, Mg alloys acting as the medical implants have drawn extensive attention, due to their spontaneous degradability, effective load-transmissibility and the excellent biocompatibility, particularly in bone tissue reconstruction and vascular radial-support. Regrettably, they were inevitably affected by the tension/compression-torsion, dynamic erosion and corrosion fatigue under complex service conditions, which lead to premature failure of implantation-materials. Micro-alloying addition is an effective way to delay the rapid degradation, especially in rare-earth micro-composite addition. It can not only reduce intensities of galvanic-corrosion by refining the grain sizes and adjusting the Volta-potentials distribution of the precipitates, but also modify the compositions and biocompatibility of the degradation products. Moreover, the higher compress tress on the surface can improve the stability and densification of the film layer, which enhanced the corrosion resistance. Thus, the latest research progress about in vivo/vitro degradation behaviors and biocompatibility of rare-earth Mg alloys is reviewed; The internal relationships between rare-earth elements, phase features and degradation behaviors of Mg alloys are summarized. Moreover, the effects of rare-earth addition on the film-characteristics are deeply explained, and the induced mechanisms of rare earth elements on the biocompatibility are revealed.
On'June 15th,the General Office of the Shanghai Municipal People's Government issued the"Three-Year Action Plan for Promoting High-Quality Development of the Manufacturing Industry in Shanghai(2023-2025)".
Chinese scientists have developed a greener and more efficient mining technique to recover rare-earth elements(REEs)from weathering crusts,revealing new paths for the sustainable harvest of natural resources.
This article briefly introduces the current industrial development status of rare earth polishing powder at home and abroad,summarizes and classifies the types and production processes of existing rare earth polishing powder,analyzes its technical status and existing problems,and the application prospects of rare earth polishing powder.
"Rare earth"has become one of the hot topics in recent years for its applications in automobile,national defense and new energy fields.The countries like the USA,Japan,the EU and China carried out different rare earth strategies largely because they either have rare earth reserves or actively involve in rare earth applications.
Recovery of rare earth elements(REEs)from mine wastewater is essential for maintaining rare earth reserves and sustainable application of REEs.In the present study,we prepared a phosphoric acid modified kaolin(P-K)adsorbent by a simple mechanochemical process for the selective recovery of REEs from rare earth wastewater.The impacts of phosphoric acid dosage,milling duration,initial pH,temperature,initial ion concentration,and adsorbent dosage on the selective adsorption of REEs were investigated.The findings demonstrate that the adsorption of REEs by P-K follows pseudo-second-order kinetic model and the Langmuir isotherm model,and is dominated by chemical adsorption,with a maximum adsorption capacity of 19.82 mg/g at 50 ℃.Additionally,in an original mine wastewater,the recovery rate of REEs can reach more than 90％,whereas the adsorption rates of calcium,magnesium and,ammonia nitrogen(whose concentration is 18 times that of REEs)are nearly zero,indicating that P-K has extremely high selectivity for REEs.Furthermore,the feedstock solution containing 40 mg/L of REEs may be concentrated to 3,510 mg/L following enrichment treatment,and 99.9％ of the REEs are eluted using a low concentration of hydrochloric acid.The findings illustrate that P-K has a wide range of potential applications in the treatment of rare earth industrial effluents.
Rare earth doping has been proved to be an effective method to improve hydrogen storage properties of Mg-based alloys.In this work,the effect of rare earth(Y,Ce,La,Sc)doping on the thermal stability,electronic property and hydrogen adsorption/desorption behavior of Mg2Ni(010)surface are systematically investigated by first principles calculation.The results show that rare earth doping in Mg2Ni(010)surface are thermodynamic feasible.The calculated electronic structures shown that rare earth atoms weaken the binding strength between H and Mg2Ni(010)substrate,thus reduce the hydrogen diffusion and desorption energies barriers,and improve the hydrogen storage properties of Mg2Ni.Among the four rare earth elements,Ce shows the best potential.Notably,the substitution doping of Ce to Mg atom significantly reduces the H diffusion barrier by 0.32 eV and H2 desorption barrier by 1.0 eV.This discovery provides a direction for the preparation of rare earth doped Mg2Ni hydrogen storage materials.
Global transition towards low-carbon future is threatened by supply risks surrounding critical raw materials, particularly the rare earth, scarce, and scattered metals (RSSM) with poor mineral endowments. Thus, the metal recycling from various end-of-life products are widely advocated and advanced as a key strategy, but the present understanding of their recycling potentials, limitations and challenges is quite scattered and limited. Here, this paper conducts a literature review, based on the PRISMA analysis of approximately 160 types of relevant studies from 2010 to 2021, to provide sophisticated knowledge related to the recycling status, progress, and future directions of 34 types of RSSM. Results indicate only a part of those metals can be recycled due to the obstacles in metal design as well as societal and economic factors in its usage and recycling, and the corresponding obstacles for each metal are further identified by key factors including complexity of the product design, more complex end-use of metal, and lack of suitable infrastructure for collection. Thus, the jointed efforts from all stakeholders along metal cycle from material design, use, throughout to final recycling are highly suggested and urged to secure metal base for future circular and low-carbon economy.
This study explores the time and frequency spillover relationship between the political risk (PR) of major importers and exporters and the stock returns of China's rare earths (RER) by using the spillover index proposed by Diebold and Yilmaz (2012, 2014) (D&Y (2012, 2014)) and Baruník and Křehlík (2018) (B&K (2018)). The research results indicate that the average total spillovers between PR and RER are 35.55%, in which short-term spillovers play a dominant role with the average proportion of 71.21%. In particular, the spillover index increases significantly during major financial and political events, including the global financial crisis, European debt crisis, China-Japan diplomatic event, the crisis between Russia and Ukraine, the announcement of WTO dispute resolution about rare earths (REs) and the US presidential election. In addition, Myanmar has the largest PR index, which is also the biggest contributor in the spillover network regardless of time periods. In terms of RER, it is a net receiver of spillovers from PR, which obtains more spillovers from importing countries than exporting countries. Generally, Japan, Estonia, Myanmar and the Netherlands are the top spillover emitters to RER while Germany, France, Japan and India are the main spillover receivers from RER. Moreover, Japan emits evidently more spillovers to RER in the long term and during major political event.
After recovering rare earth from neodymium-iron-boron(Nd-Fe-B)magnet waste via oxidation roasting-hydrochloric acid leaching,extracting rare earths and cobalt from remaining leach residue,containing about 0.67％(w/w)RE and 0.36％Co,is environmentally and economically important.
