Sample records for rare earth materials

  1. Research on Rare Earth Encapsulated Luminescent Material

    Yu Zhiwei; Liu Chengdong; Qi Xiaopeng


    A new method of preparation of irradiative material by using rare earth as luminophor and inorganic powder as base nucleus was presented.Rare earth was used to make colloid, which was mixed with base nucleus solution,where deposition/attachment reaction took place and rare earth was adhered onto the surface of base nucleus, hence yielding a new rare earth encapsulated irradiative material.Fluorescent spectrum analysis shows that this material possesses two emission peaks, one within 400 ~ 500 nm and the other within 580 ~ 700 nm, reflecting the luminous characteristics of original rare earth material.

  2. Application progress of rare earth nano-materials

    Xiao Zhe


    @@ Total rare earth consumption exceeded 72,600 tREO domestically in China in 2007, among which over 38,500 tREO were consumed in functional materials like permanent magnetic materials, fluorescent materials, hydrogen storage materials, catalytic materials and polishing powders,representing 53% of total RE consumption. Production and application of RE performance materials have been the main force promoting the development of China rare earth industry.

  3. Application of Rare Earths in Thermal Barrier Coating Materials

    Xueqiang CAO


    Rare earths are a series of minerals with special properties that make them essential for applications including miniaturized electronics, computer hard disks, display panels, missile guidance, pollution controlling catalysts,H2-storage and other advanced materials. The use of thermal barrier coatings (TBCs) has the potential to extend the working temperature and the life of a gas turbine by providing a layer of thermal insulation between the metallic substrate and the hot gas. Yttria (Y2O3), as one of the most important rare earth oxides, has already been used in the typical TBC material YSZ (yttria stabilized zirconia). In the development of the TBC materials, especially in the latest ten years, rare earths have been found to be more and more important. All the new candidates of TBC materials contain a large quantity of rare earths, such as R2Zr2O7 (R=La, Ce, Nd,Gd), CeO2-YSZ, RMeAI11O19 (R=La, Nd; Me=Mg, Ca, Sr) and LaPO4. The concept of double-ceramiclayer coatings based on the rare earth materials and YSZ is effective for the improvement of the thermal shock life of TBCs at high temperature.

  4. Spectroscopic properties of rare earths in optical materials

    Parisi, Jürgen; Osgood, R; Warlimont, Hans; Liu, Guokui; Jacquier, Bernard


    Aimed at researchers and graduate students, this book provides up-to-date information for understanding electronic interactions that impact the optical properties of rare earth ions in solids. Its goal is to establish a connection between fundamental principles and the materials properties of rare-earth activated luminescent and laser optical materials. The theoretical survey and introduction to spectroscopic properties include electronic energy level structure, intensities of optical transitions, ion-phonon interactions, line broadening, and energy transfer and up-conversion. An important aspect of the book lies in its deep and detailed discussions on materials properties and the potential of new applications such as optical storage, information processing, nanophotonics, and molecular probes that have been identified in recent experimental studies. This volume will be a valuable reference book on advanced topics of rare earth spectroscopy and materials science.

  5. Advances in Rare Earth Application to Semiconductor Materials and Devices



    The development of rare earths (RE) applications to semiconductor materials and devices is reviewed. The recent advances in RE doped silicon light emitting diodes (LED) and display materials are described. The various technologies of incorporating RE into semiconductor materials and devices are presented. The RE high dielectric materials, RE silicides and the phase transition of RE materials are also discussed. Finally, the paper describes the prospects of the RE application to semiconductor industry.

  6. Primary Results of New Rare Earth Materials for Hongti Grape

    He Qiong; Gu Jiangyuan; Wang Jiachen


    New rare earth (RE) materials including RE phosphate as base fertilizer, bioactive RE micro-fertilizer and RE entire plant nutrition agent as topdressing fertilizer are treated on Hongti grope.The result showes that the plant leaves become thicker, the color is dark green, the plant disease index is lower, and the sugar content significantly increases.

  7. Recent Progress on Nanoscale Rare Earth Luminescent Materials


    1 Results The size of nanoscale rare earth luminescent materials is often smaller than that of the excitement or emission wavelength,and it has amazing surface state density. Therefore,it shows a lot of new luminescent phenomena such as the shift of CTS,the broadening of emission peaks,the variation of fluorescent lifetimes and quantum efficiency,and the increase of quenching concentration.It is not only of academic interest but also of technological importance for advanced phosphor applications to rese...

  8. Rare earth boride electron emitter materials fabrication and evaluation

    Swanson, L. W.; Davis, P. R.; Gesley, M. A.


    Techniques were developed for routine preparation of single crystal rods of LaB6, CeB6 and PrB6 by arc float zone refining. Single crystal, oriented samples were prepared from these rods and mounted as cathodes for testing. Several mounting systems were used, and flat, pointed cone and truncated cone thermionic cathodes were studied. Pointed field emitters of LaB6(100) were also investigated. Variation of thermionic emitted current density and thermal stability of materials were studied as functions of rare earth element, bulk stoichiometry and crystal orientation. Life tests were performed on several different LaB6(100) cathodes. One such cathode operated for over 3000 hours at approximately 10 A/sq cm emitted current density with no serious physical degradation. Surface properties of the materials were investigated by various surface analysis techniques.


    Reed, D. W.; Fujita, Y.; Daubaras, D. L.; Bruhn, D. F.; Reiss, J. H.; Thompson, V. S.; Jiao, Y.


    Bioleaching offers a potential approach for recovery of rare earth elements (REE) from recyclable materials, such as fluorescent lamp phosphors or degraded industrial catalysts. Microorganisms were enriched from REE-containing ores and recyclable materials with the goal of identifying strains capable of extracting REE from solid materials. Over 100 heterotrophic microorganisms were isolated and screened for their ability to produce organic acids capable of leaching REE. The ten most promising isolates were most closely related to Pseudomonas, Acinetobacter and Talaromyces. Of the acids produced, gluconic acid appeared to be the most effective at leaching REE (yttrium, lanthanum, cerium, europium, and terbium) from retorted phosphor powders (RPP), fluidized cracking catalyst (FCC), and europium-doped yttrium oxide (YOEu). We found that an Acinetobacter isolates, BH1, was the most capable strain and able to leach 33% of the total REE content from the FCC material. These results support the continuing evaluation of gluconic acid-producing microbes for large-scale REE recovery from recyclable materials.

  10. Effect of rare earth substitution in cobalt ferrite bulk materials

    Bulai, G., E-mail: [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania); Diamandescu, L. [National Institute of Material Physics, P.O. Box MG-7, 07125 Bucharest (Romania); Dumitru, I.; Gurlui, S. [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania); Feder, M. [National Institute of Material Physics, P.O. Box MG-7, 07125 Bucharest (Romania); Caltun, O.F. [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania)


    The study was focused on the influence of small amounts of rare earth (RE=La, Ce, Sm, Gd, Dy, Ho, Er, Yb) addition on the microstructure, phase content and magnetic properties of cobalt ferrite bulk materials. The X-Ray diffraction measurements confirmed the formation of the spinel structure but also the presence of secondary phases of RE oxides or orthoferrite in small percentages (up to 3%). Density measurements obtained by Archimedes method revealed a ~1 g cm{sup −3} decrease for the RE doped cobalt ferrite samples compared with stoichiometric one. Both the Mössbauer and Fourier Transform Infrared Spectrocopy analysis results confirmed the formation of the spinel phase. The saturation magnetization and coercive field values of the doped samples obtained by Vibrating Sample Magnetometry were close to those of the pure cobalt ferrite. For magnetostrictive property studies the samples were analyzed using the strain gauge method. Higher maximum magnetostriction coefficients were found for the Ho, Ce, Sm and Yb doped cobalt ferrite bulk materials as related to the stoichiometric CoFe{sub 2}O{sub 4} sample. Moreover, improved strain derivative was observed for these samples but at higher magnetic fields due to the low increase of the coercive field values for doped samples. - Highlights: • Substitution by a large number of rare earth elements was investigated. • First reported results on magnetostriction measurements of RE doped cobalt ferrite. • The doped samples presented an increased porosity and a decreased grain size. • Increased magnetostrctive response was observed for several doped samples.

  11. Rare earth elements exploitation, geopolitical implications and raw materials trading

    Chemin, Marie-Charlotte


    Rare earth elements (REE) correspond to seventeen elements of the periodic table. They are used in high technology, cracking, electric cars' magnet, metal alloy for batteries, and also in phone construction or ceramics for electronic card. REEs are an important resource for high technology. This project targets 16 years old students in the subject "personalized aid" and will last six weeks. The purpose of this project is to develop autonomy and research in groups for a transdisciplinary work. This project gathers knowledge in geology, geography and economics. During the first session students analyze the geology applications of the REE. They begin the analysis with learning the composition in different rocks such as basalt and diorite to make the link with crystallization. Then they compare it with adakite to understand the formation of these rocks. In the second session, they study REE exploitation. We can find them as oxides in many deposits. The principal concentrations of rare earth elements are associated with uncommon varieties of igneous rocks, such as carbonatites. They can use Qgis, to localize this high concentration. In the third session, they study the environmental costs of REE exploitation. Indeed, the exploitation produces thorium and carcinogenic toxins: sulphates, ammonia and hydrochloric acid. Processing one ton of rare earths produces 2,000 tons of toxic waste. This session focuses, first, on Baotou's region, and then on an example they are free to choose. In the fourth session, they study the geopolitical issues of REE with a focus on China. In fact this country is the largest producer of REE, and is providing 95% of the overall production. REE in China are at the center of a geopolitical strategy. In fact, China implements a sort of protectionism. Indeed, the export tax on REE is very high so, as a foreign company, it is financially attractive to establish a manufacturing subsidiary in China in order to use REE. As a matter of fact

  12. Primary Study on Effects of New Rare Earth Agro-Materials on Potato

    Yang Qifeng; Mao Wanhu; Wang Jiachen; Xing Guo; Yang Jun; Liu Xiangsheng


    Using common phosphate as a check, we studied the growth and yield of potato by new rare earth agro-materials including rare earth phosphate (base fertilizer), rare earth whole plant nutrient fertilizer, and amino acid chelated rare earth ( top dressing), which were used in a single or mixed way in Dingxi city, Gansu Province.The results are as follows that ( 1 ) After using new rare earth materials, the plant height increases by 0.4 ~ 5.6 cm and the ripen period is delayed by 4 ~ 9 d.(2) They can improve the potato economic characteristics, enhance productivity, decrease black leg and late blight.The disease index is decreased by 1.6% ~ 10.6%, single plant potato number increases by 0.3 ~ 0.5, and single plant yield increases by 80 g ~ 130 g.(3) The effect of increased yield is significant, and mixed use is better than single use.In the single material treatments, rare earth phosphate is the best, rare earth whole plant nutrient fertilizer and amino acid chelated rare earth are the second, and the increased rate are 14.5%, 8.4%, 9.2% so the material mixture-rare earth phosphate mixed of rare earth whole plant nutrient fertilizer or with amino acid chelated rare earth is economically useable, and increase rate are 25.2% and 24.4% compared with common phosphate.

  13. Effects of Rare Earths on Properties and Microstructure of Automotive Friction Materials

    Xu Yue; Lu Liguo; Bai Jing


    Rare earth compounds as modifiers used widely in modern friction materials can enhance the interracial binding of constituents of materials and improve the comprehensive properties of materials evidently. However, there are still few reports on application of rare earth in automotive friction materials. In order to study the effect mechanism of rare earths in friction materials, a rare earth compound was selected as additive and the effects of materials doped with or without rare earth on friction and wear properties of materials were studied. The microstructure and worn surface morphology were observed by scanning electron microscopy and the macro performance was discussed. Worn surface element constitution of materials was analyzed by energy dispersive spectroscopy. Effect mechanism of rare earths on friction and wear behaviors of friction materials were discussed. The results show that doping rare earths in friction materials can stabilize friction Coefficient, lower the wear rate of materials and increase the impact strength of materials. The flexibility and fracture resistance of materials is greatly improved. Worn surface of materials doped with rare earth is compact and the surface adhesion is greatly enhanced.

  14. Composition, Processing Technology and Property of Ceramic Die Materials Containing Rare Earth Additives

    Xiao Guangchun; Xu Chonghai; Fang Bin


    Development and application of new ceramic die materials is one of the important topics in the field of die research. The composition, processing technology, mechanical property and engineering performance of the ceramic materials such as cermet, ZTA, TZP, TZP/Al2O3, TZP/TiC/Al2O3, PSZ and Sialon, etc., with rare earth yttrium, lanthanum and cerium, and so on working as additives, were investigated and analyzed in the present study. Problems existed in the research and application of rare earth ceramic die materials were discussed. Rare earth additives can effectively improve the mechanical property and engineering performance of ceramic die materials. Thus, it will have further perspectives of wider application. More attention should be paid in the future to the toughening and strengthening of the ceramic die materials, the adding forms and kinds of rare earth elements and acting mechanisms of rare earth additives in ceramic die materials.

  15. Rare earth-doped materials with enhanced thermoelectric figure of merit

    Venkatasubramanian, Rama; Cook, Bruce Allen; Levin, Evgenii M.; Harringa, Joel Lee


    A thermoelectric material and a thermoelectric converter using this material. The thermoelectric material has a first component including a semiconductor material and a second component including a rare earth material included in the first component to thereby increase a figure of merit of a composite of the semiconductor material and the rare earth material relative to a figure of merit of the semiconductor material. The thermoelectric converter has a p-type thermoelectric material and a n-type thermoelectric material. At least one of the p-type thermoelectric material and the n-type thermoelectric material includes a rare earth material in at least one of the p-type thermoelectric material or the n-type thermoelectric material.

  16. China Rare Earth Market Review


    @@ February, 2010 Rare earth separation plants and downstream producers like NdFeB magnetic materials and phosphor materials successively ceased production due to Spring Festival, Chinese New Year. Transactions in rare earth market were few affected by public holidays.

  17. Effect of Rare Earth Phosphate Composite Materials on Cleanout Oil-Dirty Property of Ceramics

    Liang Jinsheng; Zhang Jin; Liang Guangchuan; Wang Lijuan; Li Guosheng; Meng Junping; Pan Yanfen


    The ceramics with cleaning easily up oil-dirty property were prepared by doping enamel slurry with rare earth elements phosphate composite materials, and then the influence mechanisms of rare earth elements phosphate composite materials on the cleaning easily up oil-dirty property of ceramic were studied by testing the surface tension and contact angle of water, latex stability inside of ceramic product. Results that the ceramic doped enamel slurry with rare earth phosphate composite materials can reduce obviously the surface tension and contact angle of water, and make latex more stable, and so the ceramics possess excellent cleanout oil-dirty property.

  18. Rare Earth Market Review


    @@ Oversupply of rare earths led to the significant price drop of rare earth mineral products and separated products in Chinese domestic market. To stabilize the price, prevent waste of resources, further improve regulation capability on domestic rare earth market and rare earth price and maintain sustaining and healthy development of rare earth industry, partial rare earth producers in Baotou and Jiangxi province projected to cease the production for one month.

  19. Theoretical and Computational Studies of Rare Earth Substitutes: A Test-bed for Accelerated Materials Development

    Benedict, Lorin X. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    Hard permanent magnets in wide use typically involve expensive Rare Earth elements. In this effort, we investigated candidate permanent magnet materials which contain no Rare Earths, while simultaneously exploring improvements in theoretical methodology which enable the better prediction of magnetic properties relevant for the future design and optimization of permanent magnets. This included a detailed study of magnetocrystalline anisotropy energies, and the use of advanced simulation tools to better describe magnetic properties at elevated temperatures.

  20. Experiments of Applying the Rare-Earth Modifying Agents in New Dental Materials Preparation

    Chen Xiaohu; Wang Hua; Wang Qin; Li Xiaodi; Ma Rui


    Harmless rare-earth modifying agents were prepared by orthogonal experiments. A new resin material was synthesized with the qualities such as rigidity, rubbing abrasion, aging, luster and plasticity better than the dental resin materials in common used. It could be used as the substitutes for the applied resin teeth materials.

  1. Effects of rare earth element lanthanum on the microstructure of copper matrix diamond tool materials


    Effects of rare earth element La on the microstructure of Cu matrix diamond tools were researched under the conditions of various materials componentsand the process parameters in order to improve materials properties. SEM, XPS and X-ray were used to investigate the fracture section, microstructure and the element valence in materials. The results shown that the combination of rare earth element La and transition element Ti is advantageous to the bonding state between diamond particles and matrix, so it can improve the materials properties. Suitable sintering temperature is 790℃.

  2. Preparation and Characterization of Rare Earth Composite Materials Radiating Far Infrared for Activating Liquefied Petroleum Gas


    Rare earth composite materials radiating far-infrared rays were prepared according to far infrared absorption spectrum of main component in liquefied petroleum gas (LPG). The composite materials were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transformed infrared spectra(FTIR). The results show that after the composite materials were calcined at 873 K for 4 h, FTIR spectra of rare earth composite materials display two new peaks at 1336 and 2926 cm-1 available for activating LPG.

  3. Effect of Rare Earth Composite Ceramic Materials on Oil Combustion of Oil-Burning Boiler


    The rare earth composite ceramic materials were prepared using rare earths and far infrared natural mineral. The effects of the as-prepared ceramic materials on the oil consumption and air pollutants emissions of oil-burning boiler were investigated. The results show that the composite ceramic materials can radiate higher intensity of far infrared. The molecular movement is strengthened and the chemical bonds of the molecules are easily ruptured when the diesel oil is dealt with the composite materials. The oil-saving rate of the RBS·VH-1.5 boiler dealt with the rare earth composite ceramic materials is 3.49%, and the reducing rates of CO and NO in the exhaust gas are 25.4% and 9.7%, respectively.

  4. Photo-Catalyzed Rare Earth Materials with Ability to Translate Free Radicals into Negative Ions

    Jin Zongzhe; Zhang Zhili; Wei Gang; Huang Lirong


    Materials with function of producing negative ions effection,containing valency-variable rare earth elements and semiconductor oxide,were fabricated.Free radicals produced by the materials were tested.The result shows that the materials can produce quite a few free radicals as·O-2 no matter whether they are under illumination of ultraviolet radiation or under visible light radiation,or under no light radiation, demonstrating semiconductor oxide can be catalysed under the visible light radiation.At the same time the result shows there is direct relation between the number of free radicals and of the negative ion produced by the materials,which meant that during photo-catalyzed and redox process of valency-variable rare earth elements free radicals translate into negative ions. A circular model is presented involving circulating change of valency-variable rare earth elements and water and oxygen absorbed on the surface of materials under the condition of photocatalysis.

  5. Rare earth based nanostructured materials: synthesis, functionalization, properties and bioimaging and biosensing applications

    Escudero, Alberto; Becerro, Ana I.; Carrillo-Carrión, Carolina; Núñez, Nuria O.; Zyuzin, Mikhail V.; Laguna, Mariano; González-Mancebo, Daniel; Ocaña, Manuel; Parak, Wolfgang J.


    Rare earth based nanostructures constitute a type of functional materials widely used and studied in the recent literature. The purpose of this review is to provide a general and comprehensive overview of the current state of the art, with special focus on the commonly employed synthesis methods and functionalization strategies of rare earth based nanoparticles and on their different bioimaging and biosensing applications. The luminescent (including downconversion, upconversion and permanent luminescence) and magnetic properties of rare earth based nanoparticles, as well as their ability to absorb X-rays, will also be explained and connected with their luminescent, magnetic resonance and X-ray computed tomography bioimaging applications, respectively. This review is not only restricted to nanoparticles, and recent advances reported for in other nanostructures containing rare earths, such as metal organic frameworks and lanthanide complexes conjugated with biological structures, will also be commented on.

  6. Rare Earth Resolution

    Mei Xinyu


    BEFORE the early 1970s, China had no rare earth exports, and the world rare earth market was dominated by the United States, Europe and Japan. In the 1970s, China began to enter the world rare earth market and its share has picked up sharply in the following decades. Today, having the monopoly over global rare earth production, China must improve the benefits from rare earth production, not only from producing individual rare earth products, but also from mastering the intensive processing of rare earth products.

  7. Study on preparation and application performance of blue sky rare earth light storage and emission material

    ZHOU; Shao-hui; NI; Hai-yong; HUANG; Zhao-hui; LI; Xu-bo; DING; Jian-hong; ZHANG; Zhen


    Under reduction atmosphere, a blue sky rare earth silicate light storage and emission material was prepared by high temperature solid phase synthesis. The best constituent ratio of this material was determined through orthogonal experiment, and its excitation and emission spectra and X-ray diffraction patterns were measured. And a comparative study was conducted on its application properties.

  8. Enhanced Photoactivity of Layered Nanocomposite Materials Containing Rare Earths, Titanium Dioxide and Clay


    The nanocomposite materials containing rare earths, titanium dioxide and clay (RE/TiO2/Clay) were characterized and tested for the photocatalytic decomposition of formaldehyde. The results show that nanocomposite materials prepared by doping appropriate rare earth elements have better photocatalytic properties than that prepared by doping excessive rare earth elements. The photocatalytic mechanism of composite materials was studied by integrating the theory of photocatalysis with experiment results. Because the site of photocatalytic reaction was limited in the interspace of clay, photocatalytic reaction occurred by two steps: firstly, organic molecules dispersed into the interlayers of clay; secondly, organic molecules and photocatalyst of RE/TiO2 occurred photocatalytic reaction, resulting in forming carbon dioxide.

  9. Enhanced Laser Cooling of Rare-Earth-Ion-Doped Composite Material

    JIA You-Hua; ZHONG Biao; JI Xian-Ming; YIN Jian-Ping


    We predict enhanced laser cooling performance of rare-earth-ions-doped glasses containing nanometre-sized ultrafine particles, which can be achieved by the enhancement of local field around rare earth ions, owing to the surface plasma resonance of small metallic particles. The influence of energy transfer between ions and the particle is theoretically discussed. Depending on the particle size and the ion emission quantum efficiency, the enhancement of the absorption is predicted. It is concluded that the absorption are greatly enhanced in these composite materials, the cooling power is increased as compared to the bulk material.

  10. Solid-State Lasers for Bathymetry and Communications. Studies of Four Rare-Earth Materials.


    The envelope was cerium -doped quartz, to reduce UV emission. The lamp was operated in simmer mode. The pulse forming network contained a 50-PF...class of solid state lasing materials called rare-earth fluorides . In these materials, the host lattice is LiYF4 (often called YLF), and the active...1971-1973 in which terbium-doped rare-earth fluorides were grown, and spectroscopy and lasing measurements conducted. A sample of Tb:LiGdF4 was lased

  11. Rare Earth Market Review


    @@ Rare earth market continued drop tendency.There was not much transaction of didymium oxide and the alloy. Affected by reduced order of NdFeB magnetic materials and inactive dealings of didymium mischmetal,price of didymium mischmetal had dropped from RMB ¥95,000~98,000/ton to RMBY 93,000~95,000/ton currently.

  12. Molycorp to acquire leading rare earth processor Neo Material Technologies in $1.3 Billion Deal


    Molycorp, Inc. ("Molycorp") and /Neo Material Technologies Inc. ("Neo Materials,' or "Neo") announced on March 8th the signing of a definitive agreement under which Molycorp will acquire Neo Materials for approximately CDN $1.3 billion. This will create one of the most technologically advanced, vertically integrated rare earth companies in the world.

  13. When materials become critical : lessons from the 2010 rare earth crisis

    Sprecher, B.


    This dissertation is the culmination of over four years research on the rare earth element neodymium in the context of the 2010 REE crisis. Neodymium is a generally recognized ‘critical’ material with a relevant application in the form of NdFeB magnets, both for sustainable energy technologies as we

  14. Research on toughening mechanisms of alumina matrix ceramic composite materials improved by rare earth additive

    ZHANG Xihua; LIU Changxia; LI Musen; ZHANG Jianhua


    Mixed rare earth elements were incorporated into alumina ceramic materials. Hot-pressing was used to fabricate alumina matrix composites in nitrogen atmosphere protection. Microstructures and mechanical properties of the composites were tested. It was indicated that the bending strength and fracture toughness of alumina matrix ceramic composites sintered at 1550℃ and 28 Mpa for 30 min were improved evidently. Besides mixed rare earth elements acting as a toughening phase, AlTiC master alloys were also added in as sintering assistants, which could prompt the formation of transient liquid phase, and thus nitrides of rare earth elements were produced. All of the above were beneficial for improving the mechanical properties of alumina matrix ceramic composites.

  15. Rare-earth-doped materials for applications in quantum information storage and signal processing

    Thiel, C.W., E-mail: thiel@physics.montana.ed [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Boettger, Thomas, E-mail: tbottger@usfca.ed [Department of Physics and Astronomy, University of San Francisco, 2130 Fulton St., San Francisco, CA 94117 (United States); Cone, R.L., E-mail: cone@montana.ed [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)


    Realization of practical quantum memory and optical signal processing systems critically depends on suitable materials that offer specific combinations of properties. Solid-state materials such as rare-earth ions doped into dielectric crystals are one of the most promising candidates for several quantum information storage protocols, including quantum storage of single photons. This article provides an overview of rare-earth-doped material properties and summarizes some of the most promising materials studied in our laboratory and by other groups for applications in quantum information storage and for ultra-wide bandwidth signal processing. Understanding and controlling spectral diffusion in these materials, which ultimately limits the achievable performance of any quantum memory system, is also briefly reviewed. Applications in quantum information impose stringent requirements on laser phase and frequency stability, and employing a narrow spectral hole in the inhomogeneous absorption profile in these materials as a frequency reference can dramatically improve laser stability. We review our work on laser frequency and phase stabilization and report our recent results on using a narrow spectral hole as a passive dynamic spectral filter for laser phase noise suppression, which can dramatically narrow the laser linewidth with or without the requirement of active feedback. - Research highlights: Rare-earth materials offer key properties for quantum memory and signal processing. Physics and properties of rare-earth optical transitions in solids are reviewed. Details of 47 promising optical transitions are tabulated and compared. A new narrow-band dynamic filtering method using spectral hole burning is discussed. Results of successful passive laser phase noise suppression are presented.

  16. China rare earth market review


    June 20-30 2012 Affected by a sustained slump in the demand from downstream industries, rare earth market remained flat recently. There were not many inquiries for rare earth products in the spot market. Consumers lacked of confidence in the future market. As for the downstream industries, the market of NdFeB magnetic materials and phosphors were in the doldrums. Ceramic, catalyst and polishing powder industries maintained weak. Affected by the global economy, export market of rare earth was weak.

  17. China rare earth market review


    Rare earth market remained weak recently. Dealings of light and heavy rare earth products were sluggish. Demand for didymium and dysprosium related products was soft and purchasers were not interested in replenishing their stocks. The market of NdFeB magnetic materials and phosphors remained inactive. Meanwhile, ceramic, catalyst and polishing powder industries were weak. Affected by global economical recession, export market of rare earth remained weak.

  18. China rare earth market review


    Rare earth market was weak recently. There was still no sign of recovery in NdFeB magnetic materials and phosphors market. The market of ceramic, catalyst and polishing powder were in the doldrums. Rare earth deep processing enterprisers hesitated to purchase rare earth products and considered that there was room for further price reduction. Global economy slowed down and there was no sign of improvement yet. The export market was sluggish and transactions were inactive.

  19. Development and Application of Rare Earth Permanent Magnet (REPM) Material in Electric Machines


    With the development of permanent materials, the development and application of permanent material electric machine (REPM) have been more mature. At first the state of development and application of REPM electric machine is presented in this paper, many RMEM have been produced in volume such as the pilot exciter used for power set of large-scale thermal power station, the special RMEM synchronous motor for textile, the starter motor for automobile, the brushless permanent magnet DC motor for electric facilities, permanent magnet servomotor for numerical controlled machine tool, rare-earth torque motor, special micro-motor for automobile and so on. Secondly the field of application of REPM electric machine and remaining problems is analyzed, because of the price of the rare-earth permanent magnet materials, the cost of RMEM is currently higher than that of induction machine, on the other side the dispersibility of performance of rare-earth permanent magnet materials and the limitation of technique of integral excitation are also remaining problems, above-mentioned problems handicapped the popularization of REPMEM. At last the developing prospect and trend of REPM electric machines is described, there are four promising types of PMEM: economical type, high performance type, high efficiency and energy-saving type, micromation, intelligibility type. With the appearance of new REPM material and the improvement of its performance and the continuous perfection of performance of electric-power electronic components, the development and the application of REPM electric machines will be further progressed.

  20. [Broad excitation band alkaline-earth silicate luminescent materials activated by rare earth and its applications].

    Xia, Wei; Lei, Ming-Kai; Luo, Xi-Xian; Xiao, Zhi-Guo


    Series of novel broad excitation band phosphors M2 MgSis O7 : Eu, Dy(M = Ca, Sr) were prepared by a high temperature solid-state reaction method. The crystal structure of compound was characterized. And the effects of part substitution of alkaline-earth on crystal structure, photoluminescence spectra and luminescence properties were also investigated. It is found that the excitation band of silicate luminescent materials extend to visible region and they exhibit yellow, green and blue long after-glow luminescence after excited by ultraviolet or visible light. Ca MgSi O7 : Eu, Dy luminescent materials can be excited effectively under the 450-480 nm range and exhibit a strong emission at 536 nm, nicely combining with blue light emitted by InGaN chips to produce white light. This promises the silicate luminescent materials a potential yellow phosphor for white LED.

  1. China rare earth market review


    October 21-31,2012 Recently, dealings of rare earth remained stagnant. Consumers hesitated to increase their stocks for the fear of further decline in rare earth prices. It was difficult for suppliers to sell products and they had reduced quotations to attract buyers. It did not show demand from end users could rebound in short terms. Dealings of rare earth products in spot market were few. The market of NdFeB magnetic materials, phosphors, catalysts, polishing powders and ceramics remained sluggish. There was no sign of picking up in world economy. Export market of rare earths maintained inactive.

  2. Baotou Rare Earth Became the World’s Biggest High Performance Magnetic Material Base


    <正>The High Performance Magnetic Material Phase II Project,an industry upgrading project implemented by Inner Mongolia Baotou Iron&Steel Rare Earth(Group)Hi-tech Co.,Ltd,recently basically finished equipment commissioning,signifying that the enterprise had developed the production capacity of15000 t/a Nd-Fe-B strip casting alloy and 5000t/a Nd-Fe-B magnet,thus becoming the world’s

  3. Neutron Activation Analysis of the Rare Earth Elements (REE) - With Emphasis on Geological Materials

    Stosch, Heinz-Günter


    Neutron activation analysis (NAA) has been the analytical method of choice for rare earth element (REE) analysis from the early 1960s through the 1980s. At that time, irradiation facilitieswere widely available and fairly easily accessible. The development of high-resolution gamma-ray detectors in the mid-1960s eliminated, formany applications, the need for chemical separation of the REE from the matrix material, making NAA a reliable and effective analytical tool. While not as precise as isotopedilution mass spectrometry, NAA was competitive by being sensitive for the analysis of about half of the rare earths (La, Ce, Nd, Sm, Eu, Tb, Yb, Lu). The development of inductively coupled plasma mass spectrometry since the 1980s, together with decommissioning of research reactors and the lack of installation of new ones in Europe and North America has led to the rapid decline of NAA.

  4. Influence of Composite Phosphate Inorganic Antibacterial Materials Containing Rare Earth on Activated Water Property of Ceramics

    梁金生; 梁广川; 祁洪飞; 吴子钊; 冀志江; 金宗哲


    Antibacterial ceramic was prepared by doping enamel slurry with composite phosphate inorganic antibacterial materials containing rare earth (inorganic antibacterial additives), and then the mechanisms for activating water and improving seed germinative property were tested by nuclear magnetic resonance (NMR) and the method of testing oxygen dissolved in activated water. Results show that the half peak width of 17O-NMR for tap water activated by the antibacterial ceramic drops from 115.36 to 99.15 Hz, and oxygen concentrations of activated water increase by 20%, germinate rate of horsebean and earthnut seeds increases by 12.5% and 7.5%, respectively. Therefore antibacterial ceramic doped enamel slurry with inorganic antibacterial additives containing rare earth can reduce the volume of clusters of water molecules, improve activation of tap water, and promote plant seeds germinate.

  5. Japanese Rare Earth Market


    Since China cancelled export rebate in May this year,prices of magnetic materials related rare earth productscontinuously rose. Increasing production cost is largelyattributed to investment in environmental protectionequipments. Prices of Nd and Dy metals rose 20~30% over thebeginning of this year.Price of Nd was USD 11.5 - 12/Kg from USD 9/Kg at theend of 2004, up 30%. Price of Dy rose to USD 65- 70/Kg fromUSD 50/Kg early this year, up 20%. Price of Pr climbed to USD13.5 - 14/Kg from USD 11/Kg, up 30%. Pri...

  6. China rare earth market review


    Rare earth market remained stagnant recently. The buyers did not show willingness to replenish raw materials affected by weak demand. Most persons in rare earth circle were not confident with the short-term rare earth market. Demand for didymium mischmetal was soft recently. The market of dysprosium related products was quiet and NdFeB magnet producers were inactive in the purchase. Phosphor market was stagnant as well. Buyers were cautious on replenishing the material. There were few inquiries for europium oxide (99.9%) in spot market and transactions were difficult.

  7. Improved Electrical Insulation of Rare Earth Permanent Magnetic Materials With High Magnetic Properties

    CHANG Ying; WANG Da-peng; LI Wei; PAN Wei; YU Xiao-jun; QI Min


    Rare earth permanent magnetic materials are typical electrical conductor, and their magnetic properties will decrease because of the eddy current effect, so it is difficult to keep them stable for a long enough time under a high frequency AC field. In the present study, as far as rare earth permanent magnets are concerned, for the first time, rare earth permanent magnets with strong electrical insulation and high magnetic performance have been obtained through experiments, and their properties are as follows:(1) Sm2TM17: Br=0.62 T, jHc=803.7 kA/m, (BH)m= The magnetic properties of Sm2TM17 and NdFeB are obviously higher than those of ferrite permanent magnet, and the electric insulating characteristics of Sm2TM17 and NdFeB applied have in fact been approximately the same as those of ferrite. Therefore, Sm2TM17 and NdFeB will possess the ability to take the place of ferrite under a certain high frequency AC electric field.

  8. Experiment on Nonlinear Properties Coupling Electromagnetism with Mechanics of Giant Rare Earth Magnetostrictive Materials

    Yuan Huiqun; Sun Huagang


    The electromagnetic and mechanical coupling properties of giant rare earth giant magnetostriction material TbxDy1 -xFe2 -z (0. 27 ≤x ≤ 0.3, 0 ≤ z ≤ 0.1 ) alloys were investigated by means of self-fabricated test apparatus. The effect of coupling mechanical with electromagnetic on magnetostrictive strain coefficient was discussed. The physical model of the coupling system was established. Based on the equivalent circuit of the coupling system, the magnetomechanical coupling coefficient was derived by means of impedance resistance analysis method.

  9. Rare Earth Market Review


    @@ July 20~31 Rare earth market still went downward, which was mainly led by sluggish demand for didymium products. Weak demand by domestic NdFeB market was attributed to continuous price falling of didymium mischmetal.

  10. Processing of rare earth concentrates

    Pamela Alex; R. C. Hubli; A.K. Suri


    The paper describes process details for extraction of rare earths from an intermediate grade concentrate of Madhya Pradesh region in India and a South African slag. The xenotime concentrate obtained from the former place was an intermediate grade (47%) rare earth phosphate containing both monazite and xenotime. The South African slag was a low-grade waste product typically containing only 4% of rare earths. The rare earth resource concentrates have been treated individually by different methods such as alkali fusion and alkali leaching to convert them into their mixed oxides. Both types of materials have been processed and greater than 98% solubilization of metal values has been achieved in the intermediate grade xenotime and 80% from the South African slag. The residue of xenotime hydroxide has been washed thoroughly to collect the sodium phosphate, as by-product and the slurry pH have been adjusted to separate rare earths from thorium effectively. Other impurities such as uranium and iron have been removed by precipitation of rare earths by oxalic acid. It has been possible to recover >95% yttrium along with other rare earth oxides.

  11. Preparation, Characterization and Luminescent Properties of MCM-41 Type Materials Impregnated with Rare Earth Complex


    Hybrid materials incorporating Eu-(TTA)3.2H2O(hereafter designated as Eu-TTA, with TTA:thenoyltrifluoroacetone)in unmodified or modified MCM-41 by 3-aminopropyl-triethoxysilane (APTES)were prepared by impregnation method.The obtained materials were characterized using X-ray diffraction(XRD),IR and diffuse reflectance spectroscopy and luminescence spectra.All the hybrid samples exhibited the characteristic emission bands of Eu3+ under UV light excitation at room temperature, and the excitation spectra showed significant blue-shifts compared to the pure rare-earth complex. Although the red emission intensity in the modified hybrid was almost the half of the red emission intensity in the pure Eu-TTA complex at room temperature,the hybrid showed a much higher thermal stability due to the shielding character of the MCM-41host.

  12. High pressure {mu}SR studies: rare earths and related materials

    Kalvius, G.M., E-mail:; Schreier, E. [Technical University Munich, Physics Department (Germany)], E-mail:; Ekstroem, M.; Hartmann, O. [Uppsala University, Physics Department (Sweden); Henneberger, S., E-mail:; Kratzer, A. [Technical University Munich, Physics Department (Germany)], E-mail:; Waeppling, R. [Uppsala University, Physics Department (Sweden); Martin, E., E-mail:; Burghart, F.J. [Technical University Munich, Physics Department (Germany)], E-mail:; Ballou, R.; Deportes, J. [CNRS, Laboratoire Louis Neel (France); Niedermayer, Ch. [University of Constance, Faculty of Physics (Germany)


    After a short introduction to {mu}SR with respect to the study of magnetic properties, followed by a brief outline of the principle of the high pressure-low temperature {mu}SR spectrometer installed at the Paul Scherrer Institute, we discuss some measurements on rare earth materials employing this instrument. They are concerned with: (1) The pressure dependence of the spin turning process in ferromagnetic Gd. (2) The volume dependence of the internal magnetic field in the heavy rare earth metals Gd, Dy, and Ho in their ordered magnetic states. (3) The response of the (first order) magnetic transition in the frustrated antiferromagnets of type RMn{sub 2} (R = Y,Gd) to pressure. (4) The variation of magnetic parameters with pressure in La{sub 2}CuO{sub 4} (powder sample), the antiferromagnetic parent compound of the high T{sub C} superconductors of type La{sub 2-x}(Sr, Ba){sub x}CuO{sub 4}. In conclusion a short outlook on further developments is given.

  13. Radiation Field Forming for Industrial Electron Accelerators Using Rare-Earth Magnetic Materials

    Ermakov, A. N.; Khankin, V. V.; Shvedunov, N. V.; Shvedunov, V. I.; Yurov, D. S.


    The article describes the radiation field forming system for industrial electron accelerators, which would have uniform distribution of linear charge density at the surface of an item being irradiated perpendicular to the direction of its motion. Its main element is non-linear quadrupole lens made with the use of rare-earth magnetic materials. The proposed system has a number of advantages over traditional beam scanning systems that use electromagnets, including easier product irradiation planning, lower instantaneous local dose rate, smaller size, lower cost. Provided are the calculation results for a 10 MeV industrial electron accelerator, as well as measurement results for current distribution in the prototype build based on calculations.

  14. Rare (Earth Elements [score

    Camilo Méndez


    Full Text Available Rare (Earth Elements is a cycle of works for solo piano. The cycle was inspired by James Dillon’s Book of Elements (Vol. I-V. The complete cycle will consist of 14 pieces; one for each selected rare (earth element. The chosen elements are Neodymium, Erbium, Tellurium, Hafnium, Tantalum, Technetium, Indium, Dysprosium, Lanthanium, Cerium, Europium, Terbium, Yttrium and Darmstadtium. These elements were selected due to their special atomic properties that in many cases make them extremely valuable for the development of new technologies, and also because of their scarcity. To date, only 4 works have been completed Yttrium, Technetium, Indium and Tellurium.

  15. Sol-gel-derived hybrid materials multi-doped with rare-earth metal ions

    Zelazowska, E.; Rysiakiewicz-Pasek, E.; Borczuch-Laczka, M.; Cholewa-Kowalska, K.


    Four different hybrid organic-inorganic materials based on TiO2-SiO2 matrices with organic additives and doped with rare-earth metal ions (III) from the group of europium, cerium, terbium, neodymium, dysprosium and samarium, were synthesized by sol-gel method. Tetraethyl orthosilicate, titanium (IV) isopropoxide and organic compounds, such as butyl acrylate, butyl methacrylate, ethyl acetoacetate, ethylene glycol dimethacrylate, ethyl acetate, propylene carbonate, organic solvents and certain inorganic salts were used in the synthesis. The inorganic part of the sols, which were used in the synthesis of all the hybrid materials, was prepared separately and then the organic parts were added. The materials obtained were aged for three weeks at room temperature and then heated in an electric oven for three hours at temperatures of 80 °C-150 °C. Scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM/EDX); X-ray diffraction (XRD); Fourier transform infrared spectroscopy (KBr technique); 29Si magic-angle spinning nuclear magnetic resonance; and fluorescence spectroscopy were used for the examination of morphology, microstructure and luminescence properties, respectively. Photoluminescence properties with relatively intense narrow emission lines of Tb, Eu, Dy, Nd, Sm respectively to the RE-ions doping, were observed for all the hybrid materials.

  16. Magnetic rare earth superlattices

    Majkrzak, C.F.; Kwo, J.; Hong, M.;


    Advances in molecular beam epitaxy deposition techniques have recently made it possible to grow, an atomic plane at a time, single crystalline superlattices composed of alternating layers of a magnetic rare earth, such as Gd, Dy, Ho, or Er, and metallic Y, which has an identical chemical structure...

  17. Rare Earth based Sol-Gel Materials: An Intra- and Inter- Collegiate Collaborative Research Project

    Silversmith, Ann


    Sol-gel glasses containing rare earth (RE) impurities form an exciting class of new optical materials with potential uses as phosphors and solid state laser media. The low temperature glass synthesis based on the liquid organic precursor tetramethoxysilane allows incorporation of higher RE concentrations than in traditional melt glasses without compromising the amorphous character of the material. The synthesis and spectroscopic characterization of these materials have together formed the basis for a fruitful interdisciplinary and multi-institutional research collaboration. All materials used in this project are made by Hamilton College chemistry students; spectroscopy experiments are performed by students and faculty in the physics departments at Hamilton, Franklin and Marshall, and Davidson Colleges. In this talk results from two ongoing spectroscopic investigations will be presented, both connected to the long-term goal of improving the low fluorescence efficiency of these materials. The first is the chelation of the RE metal to create an enhanced fluorescence excitation path and to physically separate the RE from the sol-gel matrix. Chelating molecules absorb strongly in the uv, and subsequent energy transfer can produce intense visible emission from the RE. Results are presented for the chelating agent 2,6-pyridine-dicarboxylic acid (PDC) bound to europium ions and incorporated into gels. Red emission from europium follows excitation into the PDC absorption band below 300nm. The second investigation focuses on fluorescence quenching of blue emission from trivalent terbium. Two separate mechanisms -energy transfer from terbium to residual hydroxide ions and among terbium ions - lead to reduced intensity of the blue emission lines relative to other longer wavelength signals.

  18. Effects of rare earth elements on properties of AB5-type electrode materials at different temperature


    Discharge property is an important factor to evaluate electrode materials. The discharge capacity of the hydrogen-storing alloys are not only influenced by its thermodynamic property but also closely related to its dynamic property. When the temperature changes, the degrees of influence of the above-mentioned two factors on the discharge performance vary accordingly. As a consequence, adjusting compositions of the alloys to make them have good discharge performance under a relatively wide range of temperature is of great significance. On the basis of great deal of experimental investigation, the optimum combination of rare earth elements in hydrogen-storing electrode materials using at-30-55℃ is determined and the relationships between the cell parameters and discharge performance of alloys at -30℃ are discussed. Additionally, the DFEC calculation method has been improved to predict the discharge capacities, which is in good agreement with the experimental ones. This is of theoretical significance in investigating new hydrogen-storing alloys of the AB5 type.

  19. Afganistan and rare earths

    Emilian M. Dobrescu


    Full Text Available On our planet, over a quarter of new technologies for the economic production of industrial goods, are using rare earths, which are also called critical minerals and industries that rely on these precious items being worth of an estimated nearly five trillion dollars, or 5 percent of world gross domestic product. In the near future, competition will increase for the control of rare earth minerals embedded in high-tech products. Rare minerals are in the twenty-first century what oil accounted for in the twentieth century and coal in the nineteenth century: the engine of a new industrial revolution. Future energy will be produced increasingly by more sophisticated technological equipment based not just on steel and concrete, but incorporating significant quantities of metals and rare earths. Widespread application of these technologies will result in an exponential increase in demand for such minerals, and what is worrying is that minerals of this type are almost nowhere to be found in Europe and in other industrialized countries in the world, such as U.S. and Japan, but only in some Asian countries, like China and Afghanistan.

  20. Spectroscopic analyses of trivalent rare-earth ions doped in different host materials

    Chandrasekharan, Sreerenjini


    Trivalent rare-earth (RE3+) ions of 4f n electronic configurations are found to possess potential applications in the field of optoelectronic and biophotonic technologies owing to their unique optical properties. They have been used as optical activators in a large number of solid-state laser host materials due to their rich energy level structure. This work focuses on the spectroscopic study of two RE 3+ ions, namely, trivalent erbium and neodymium (Er3+ and Nd3+, respectively), embedded in some important single crystal and nanocrystalline host materials including yttrium orthoaluminate (YAlO3), erbium oxide (Er2O3), yttrium oxide (Y2O3) and a combined host system of Y2O 3 and a vinyl polymer named Polymethyl Methacrylate (PMMA). Each one of these host materials are known to be unique for their characteristic properties such as chemical durability, thermal stability, optical clarity, wide band gaps, biocompatibility, and success as phosphors in various optoelectronic devices. The complete material characterization has been performed through morphology analyses using advanced microscopy techniques and spectroscopic analyses of the characteristic absorption and emission spectra by applying phenomenological crystal-field splitting and Judd-Ofelt techniques. The important spectroscopic parameters such as line strengths, radiative decay rates, and branching ratios have been obtained for the intermanifold transitions from the upper multiplets to the corresponding lower-lying multiplet manifolds 2S+1LJ of RE3+ ions doped in various host systems. Using the radiative decay rates, radiative life times are obtained and the experimental analyses of the fluorescent spectra yield the measured lifetimes of emitting metastable states. Finally, the results are compared with the previously published set of values for the same ions doped in similar type of host systems. Detailed analyses of the spectroscopic properties show that the studied systems RE3+ doped single crystals and

  1. Multifunctional rare earth or bismuth oxide materials for catalytic or electrical applications

    Gavarri J.R.


    Full Text Available We present a review on catalytic or electrical properties of materials based on rare earth (RE oxides (CeO2, La2O3, Lu2O3 or bismuth based composite systems CeO2-Bi2O3, susceptible to be integrated into catalytic microsystems or gas sensors. The polycrystalline solids can be used as catalysts allowing conversion of CO or CH4 traces in air-gas flows. Fourier Transform infrared spectroscopy is used to determine the conversion rate of CO or CH4 into CO2 through the variations versus time and temperature of vibrational band intensities. The time dependent reactivities are interpreted in terms of an adapted Avrami model. In these catalytic analyses the nature of surfaces of polycrystalline solids seems to play a prominent role in catalytic efficiency. Electrical impedance spectroscopy allows analyzing the variation of conductivity of the system CeO2-Bi2O3. In this system, the specific high ionic conduction of a Bi2O3 tetragonal phase might be linked to the high catalytic activity.

  2. Study on BSTO/MgO Ferroelectric Materials for Phase Shift Doped with Rare Earth Oxides

    Yang Chunxia; Zhou Hongqing; Liu Min; Wu Hongzhong


    Barium strontium titanate/magnesia (BSTO/MgO) ferroelectric materials for phase shift were prepared by traditional ceramic process-solid phase synthesis. The effects of various rare earth oxides of 0.5% on dielectric behaviors of BSTO/MgO composites were studied in terms of permittivity, loss tangent and tunability both at low and high frequencies. The dielectric constant of Y2O3 and Er2O3 doped samples decreases from 160 to 120, and the microwave loss of La2O3 and Er2O3 doped samples decreases from 8.2×10-3 to 6.8×10-3. Only La2O3 increases the tunability of BSTO/MgO system, from 13.6% to 14.8%. For the La2O3 doped sample, the value of tunability is more than 14% with the external DC field 4000 V*mm-1 and the microwave loss at 2.47 GHz is 6.77×10-3 and, hence, it can basically meet the requirements of phase shifters working at microwave frequencies. The influence mechanism was discussed preliminarily.

  3. Rare earth elements and critical metal content of extracted landfilled material and potential recovery opportunities

    Gutiérrez-Gutiérrez, Silvia C.; Coulon, Frédéric; Jiang, Ying; Wagland, Stuart, E-mail:


    Highlights: • Samples from multiple core drills were obtained from 4× landfill sites in the UK. • Each sample analysed for rare earth elements, critical metals and valuable metals. • Two stage microwave digestion method ensuring high yield. • High quantities of copper and aluminium were observed in the soil layers of landfill. • Across 4× landfills aluminium and copper present has a value of around $400 million. - Abstract: Rare earth elements (REEs), Platinum group metals (PGMs) and other critical metals currently attract significant interest due to the high risks of supply shortage and substantial impact on the economy. Their uses in many applications have made them present in municipal solid waste (MSW) and in commercial and industrial waste (C&I), since several industrial processes produce by-products with high content of these metals. With over 4000 landfills in the UK alone, the aim of this study was to assess the existence of these critical metals within landfills. Samples collected from four closed landfills in UK were subjected to a two-step acid digestion to extract 27 metals of interest. Concentrations across the four landfill sites were 58 ± 6 mg kg{sup −1} for REEs comprising 44 ± 8 mg kg{sup −1} for light REEs, 11 ± 2 mg kg{sup −1} for heavy REEs and 3 ± 1 mg kg{sup −1} for Scandium (Sc) and 3 ± 1.0 mg kg{sup −1} of PGMs. Compared to the typical concentration in ores, these concentrations are too low to achieve a commercially viable extraction. However, content of other highly valuable metals (Al and Cu) was found in concentrations equating to a combined value across the four landfills of around $400 million, which increases the economic viability of landfill mining. Presence of critical metals will mainly depend on the type of waste that was buried but the recovery of these metals through landfill mining is possible and is economically feasible only if additional materials (plastics, paper, metallic items and other) are

  4. Rare Earth Oxide Thin Films

    Fanciulli, Marco


    Thin rare earth (RE) oxide films are emerging materials for microelectronic, nanoelectronic, and spintronic applications. The state-of-the-art of thin film deposition techniques as well as the structural, physical, chemical, and electrical properties of thin RE oxide films and of their interface with semiconducting substrates are discussed. The aim is to identify proper methodologies for the development of RE oxides thin films and to evaluate their effectiveness as innovative materials in different applications.

  5. Synthesis and characterization of rare earth doped novel optical materials and their potential applications

    Pokhrel, Madhab

    There are many application of photonic materials but selection of photonic materials are always constrained by number of factors such as cost, availability of materials, thermal and chemical stability, toxicity, size and more importantly ease of synthesis and processing along with the efficient emission. For example, quantum dots are efficient emitter but they are significantly toxic, whereas dyes are also efficient emitters but they are chemically unstable. On the other hand, display and LED requires the micron size particles but bio application requires the nano-sized particles. On the other hand, laser gain media requires the ceramics glass or single crystal not the nanoparticles. So, realization of practical optical systems critically depends on suitable materials that offer specific combinations of properties. Solid-state powders such as rare-earth ions doped nano and micron size phosphors are one of the most promising candidates for several photonic applications discussed above. In this dissertation, we investigate the upconversion (UC) fluorescence characteristics of rare earth (RE) doped M2O2S (M = Y, Gd, La) oxysulphide phosphors, for near-infrared to visible UC. Both nano and micron size phosphors were investigated depending on their applications of interest. This oxysulphide phosphor possesses several excellent properties such as chemical stability, low toxicity and can be easily mass produced at low cost. Mainly, Yb3+, Er3+, and Ho3+ were doped in the host lattice, resulting in bright red, green, blue and NIR emissions under 980 nm and 1550 nm excitation at various excitation power densities. Maximum UC quantum yields (QY) up to 6.2 %, 5.8%, and 4.6% were respectively achieved in Yb3+/Er3+ :La2O2S, Y2O2S, and Gd2O 2S. Comparisons have been made with respect to reported most efficient upconverting phosphors beta-NaYF4:20 % Yb/ 2% Er. We believe that present phosphors are the most efficient and lower excitation threshold upconverting phosphors at 980 and

  6. China Rare Earth Market Review


    @@ Active demands from downstream industry drove the price rise of rare earth products in Chinese domestic marketrecently, particularly didymium and dysprosium products. Prices of other rare earth products remained stable.

  7. China rare earth market review


    Rare earth market fluctuated slightly recently and the transactions remained sluggish. Environment control was strengthened in southern China and many rare earth plants had gone out of production. Some traders were considering selling commodities at low p

  8. Hunan Rare Earth Group Approved


    <正>Following Guangdong,Guangxi,Fujian and Jiangxi,Hunan announced that it would consolidate its rare earth resources-the consolidation plan of Hunan Rare Earth Group has been approved. Consolidation of the rare earth industry of south China is in full swing.According to "Several Opinions of the State Council on Promoting the Sustainable and Healthy Development of Rare Earth Industry"(hereinafter referred to as "Several Opinions")released in 2011,

  9. China Rare Earth Market Review


    September 20-30, 2011 Rare earth market remained steady recently. Quoted prices of didymium products by separation and smelting plants kept stable. Some rare earth industrial zones in Baotou, Sichuan and Ganzhou had suspended production with the intensified environmental protection control and consolidation of rare earth industry. Persons in the industry hold a positive attitude toward the rare earth market after the National Day' s holiday in China. The market will develop healthily and orderly in the future.

  10. China Rare Earth Market Review


    @@ Supply of rare earth concentrate remained tight recently. Rare earth market exhibited rising tendency holistically Affected by tight supply of rare earth concentrate, many plants were operated under the capacity. Supply of didymium oxide got tighter and the price was on rising.

  11. Rare Earths and Magnetic Refrigeration


    Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrigerants in most cooling devices, and for many cooling application the Nd2Fe14B permanent magnets are employed as the source of the magnetic field. The status of the near room temperature magnetic cooling was reviewed.

  12. Recovering heavy rare earth metals from magnet scrap

    Ott, Ryan T.; McCallum, Ralph W.; Jones, Lawrence L.


    A method of treating rare earth metal-bearing permanent magnet scrap, waste or other material in a manner to recover the heavy rare earth metal content separately from the light rare earth metal content. The heavy rare earth metal content can be recovered either as a heavy rare earth metal-enriched iron based alloy or as a heavy rare earth metal based alloy.

  13. New Mid-IR Lasers Based on Rare-Earth-Doped Sulfide and Chloride Materials

    Nostrand, M


    Applications in remote-sensing and military countermeasures have driven a need for compact, solid-state mid-IR lasers. Due to multi-phonon quenching, non-traditional hosts are needed to extend current solid-state, room-temperature lasing capabilities beyond {approx} 4 {micro}m. Traditional oxide and fluoride hosts have effective phonon energies in the neighborhood of 1000 cm{sup -1} and 500 cm{sup -1}, respectively. These phonons can effectively quench radiation above 2 and 4 {micro}m, respectively. Materials with lower effective phonon energies such as sulfides and chlorides are the logical candidates for mid-IR (4-10 {micro}m) operation. In this report, laser action is demonstrated in two such hosts, CaGa{sub 2}S{sub 4} and KPb{sub 2}Cl{sub 5}. The CaGa{sub 2}S{sub 4}:Dy{sup 3+} laser operating at 4.3 {micro}m represents the first sulfide laser operating beyond 2 {micro}m. The KPb{sub 2}Cl{sub 5}:Dy{sup 3+} laser operating at 2.4 {micro}m represents the first operation of a chloride-host laser in ambient conditions. Laser action is also reported for CaGa{sub 2}S{sub 4}:Dy{sup 3+} at 2.4 {micro}m, CaGa{sub 2}S{sub 4}:Dy{sup 3+} at 1.4 {micro}m, and KPb{sub 2}Cl{sub 5}:Nd{sup 3+} at 1.06 {micro}m. Both host materials have been fully characterized, including lifetimes, absorption and emission cross sections, radiative branching ratios, and radiative quantum efficiencies. Radiative branching ratios and radiative quantum efficiencies have been determined both by the Judd-Ofelt method (which is based on absorption measurements), and by a novel method described herein which is based on emission measurements. Modeling has been performed to predict laser performance, and a new method to determine emission cross section from slope efficiency and threshold data is developed. With the introduction and laser demonstration of rare-earth-doped CaGa{sub 2}S{sub 4} and KPb{sub 2}Cl{sub 5}, direct generation of mid-IR laser radiation in a solid-state host has been demonstrated. In

  14. Computer simulations of rare earth sites in glass: experimental tests and applications to laser materials

    Weber, M.J.


    Computer simulations of the microscopic structure of BeF/sub 2/ glasses using molecular dynamics are reviewed and compared with x-ray and neutron diffraction, EXAFS, NMR, and optical measurements. Unique information about the site-to-site variations in the local environments of rare earth ions is obtained using optical selective excitation and laser-induced fluorescence line-narrowing techniques. Applications and limitations of computer simulations to the development of laser glasses and to predictions of other static and dynamic properties of glasses are discussed. 35 references, 2 figures, 2 tables.

  15. Powder metallurgical processing of magnetostrictive materials based on rare earth-iron intermetallic compounds

    Malekzadeh, M.


    Procedures are described for fabrication of high density rare earth-iron magnetostrictive compounds by powder metallurgical techniques. The fabrication involves a sequence of steps which includes preparing the pre-alloyed compounds, pulverizing them into a fine powder, compacting in suitable sizes and shapes, and sintering. Samples prepared by these procedures are carefully characterized by scanning electron microscopy, x-ray diffraction, dilatometry, and magnetic measurements. Process steps are found to exert important influences upon densities, microstructure and magnetic properties attained after densification. Investigations on a number of these process steps, including milling time and medium, sintering, and magnetic powder alignment are described.

  16. Palladium-rare-earth metal alloys-advanced materials for hydrogen power engineering


    Hydrogen of no less than 99. 999 % (vol. fraction) purity is a principal power media of hydrogen power engineering. A single method for the preparation of high purity hydrogen consists in its separation from vapour-gas mixtures via the selective diffusion of hydrogen through a palladium membrane. The rate of hydrogen diffusion and the strength and stability during the operation in aggressive gases are important characteristics of palladium membranes. The increase in the strength, plasticity, and hydrogen-permeability of membrane alloys can be reached by alloying palladium with the formation of solid solutions.The formation of wide ranges of palladium-rare-earth metal (REM) solid solutions is an interesting feature of palladium. Earlier, we have shown that the alloying of Pd with REM substantially increases the rate of hydrogen diffusion and markedly increases the strength of palladium on retention of the adequate plasticity.In this work, we have studied alloys of the Pd-Y and Pd-Y-Me systems. It was shown that the following conditions should be satisfied to prepare high-quality alloys exhibiting high service properties: (1)the use of high-purity components (whose purity is no less than 99.95%, mass fraction), in particular,high-purity Y prepared by vacuum distillation, and (2) holding the reached purity for the final product.For this purpose, we suggested a cycle of manufacturing operations including the preparation of a vacuumtight foil of 50 (m thick as the final stage.The hydrogen-permeability of the alloys was measured at different temperatures and hydrogen pressures. The instability of operation of binary Pd-Y alloys w alloying the composition with a Ⅷ Group metal. For example, the alloy of the optimum composition Pd-8Y-Me in the annealed state exhibits the following mechanical properties: HV= 75 kg/mm2 , σu = 58 kg/mm2 , and δ= 20%. Its hydrogen-permeability (QH2) measured as a function of the temperature exceeds that of the Pd-23Ag alloy (that is widely

  17. Application and Demonstration of a Series of Rare Earth Drought Resistant Materials in Western Area of China

    Wang Guoqiang; Wang Jiachen


    The application and effects for a series of rare earth (RE) drought resistant materials used in arid, salina,hungriness, wind defending and sand fixing matter, withdraw farming and return to grass and forest in western of China were reported.The important discussion was technological innovation within two years: such as seed clothing agent,RE liquid field film, RE grass and woods transplant living agent, and RE complex pesticide development and application.

  18. Estimation of the physico-chemical parameters of materials based on rare earth elements with the application of computational model

    Mamaev, K.; Obkhodsky, A.; Popov, A.


    Computational model, technique and the basic principles of operation program complex for quantum-chemical calculations of material's physico-chemical parameters with rare earth elements are discussed. The calculating system is scalable and includes CPU and GPU computational resources. Control and operation of computational jobs and also Globus Toolkit 5 software provides the possibility to join computer users in a unified system of data processing with peer-to-peer architecture. CUDA software is used to integrate graphic processors into calculation system.

  19. Formation cause,composition analysis and comprehensive utilization of rare earth solid wastes

    许涛; 彭会清


    Based on practical situation of rare earth industrial chain,production process and rare earth materials that could produce solid wastes on batch were discussed.Formation cause,formation volume,composition analysis and comprehensive utilization of the solid wastes of rare earth hydrometallurgy slag,electrolysis slag,Fe-based rare earth permanent magnetic materials,Co-based rare earth permanent magnetic materials,rare earth hydrogen storage materials,rare earth polishing powders and rare earth catalysts were ...

  20. China Rare Earth Market Review


    Rare earth market was relatively stable recently. There was not much change to the quotations by suppliers. Inquiries for most products increased in spot market and so did to the transactions. Recently, rare earth special invoices attracted the attention in the industry again. It is likely to result in price rise of many rare earth products if the special invoice system can put into effect in the near term.

  1. China rare earth market review


    November 1-10, 2012 Some key rare earth producers had paused production since the last ten day period of October in order to retain normal production and market order and stabilize rare earth prices. The production suspension measure by the plants together with severe cracking down on illegal mining by the government had some influence on sluggish market recently. Data showed rapid price increase of major rare earth products after sharp decline previously.

  2. China Rare Earth Market Review


    Rare earth market remained sluggish and quiet holistically recently. Didymium-related market was quiet and the consumers were hesitating in replenishing their inventories. Inquiries for dysprosium-related products were few and the transactions were inactive, Demand for europium oxide (99.99%) was weak and the trade was far from brisk. Baogang Rare Earth suspended production, which has a positive effect in stabilizing the whole rare earth market. But prices of rare earth products did not go up rapidly. This means there were still large inventories in the market.

  3. Rare earth monopnictides and monochalcogenides from first principles: towards an electronic phase diagram of strongly correlated materials

    Petit, Leon; Tyer, R.; Szotek, Z.


    We present the results of an ab initio study of the electronic structure of 140 rare earth compounds. Specifically, we predict an electronic phase diagram of the entire range of rare earth monopnictides and monochalcogenides, composed of metallic, semiconducting and heavy fermion-like regions...... and exhibiting valency transitions brought about by a complex interplay between ligand chemistry and lanthanide contraction. The calculations exploit the combined effect of a first-principles methodology, which can adequately describe the dual character of electrons, itinerant versus localized, and high...... calculated to within ~1.5% of the experimental values, and its ability to describe localization phenomena in solids, makes it a competitive atomistic simulation approach in the search for and design of new materials with specific physical properties and possible technological applications....

  4. Effect of rare earth ions on transition temperature in perovskite materials by on-line ultrasonic studies

    Sundararaman Sankarrajan


    Full Text Available On-line measurements of ultrasonic longitudinal velocity, shear velocity and longitudinal attenuation were carried out on R1-xSr xMnO3 perovskites (R = La, Pr, Nd and Sm for different compositions of Sr, at a fundamental frequency of 5 MHz over wide range of temperatures using the through-transmission method. The observed maxima/minima in velocities and attenuation have been discussed with decrease in ionic radii and composition. As a decrease in the ionic radii of rare earth elements leads to a decrease in transition temperature (Tc, the results that are observed show that measurement is one of the best tools to explore the structural/phase transition on-line velocity in perovskite manganese materials as a function of the ionic radii of rare earth elements.

  5. Review on Rare Earth/Polymer Composite

    刘力; 张立群; 赵素合; 金日光; 刘美琳


    The special properties of rare earth/polymer composite were described. More emph asis was put on the radiation shielding and magnetic properties. In the applicat ion to X-ray shielding, rare earth/polymer composite can make up the feeble abs o rbing area. If the rare earth content is high enough, it can demonstrate strong ability for thermal neutron absorption; The composite has strong paramagnetism. The feasibility of preparing magnetic rare earth/polymer composite was discussed . In addition, three preparation methods were introduced: simple polymerization, mixing and reaction processing. The effect of the rare earth/polymer composites pre -sturcture and the coordinate number of rare earth ions on the light property w as a nalyzed. Rare earth/polymer composite may have the structure and property simlar to those of the ionomer. The feasibility of the in-situ preparation of the rare earth/polymer nano structure is indicated. Besides, the relationship betwe en structure and properties of the rare earth/polymer composite was discussed. T he problems associated with such composite materials were also presented.

  6. Prices of Rare Earth Products Tend to Rise(Continued)


    8. Ji Daiyu, General Manager of Baotou Xinyuan RareEarth Hi-Tech Materials Co. LtdControl gross to stabilize prices. Chinese rare earth is precious strategic resource. The more it is exploit, the less it will be. The State has put forward rare earth policy of "strengthen management, protect resource, develop scientifically and face international". Chinese rare earth

  7. China's rare-earth industry

    Tse, Pui-Kwan


    Introduction China's dominant position as the producer of over 95 percent of the world output of rare-earth minerals and rapid increases in the consumption of rare earths owing to the emergence of new clean-energy and defense-related technologies, combined with China's decisions to restrict exports of rare earths, have resulted in heightened concerns about the future availability of rare earths. As a result, industrial countries such as Japan, the United States, and countries of the European Union face tighter supplies and higher prices for rare earths. This paper briefly reviews China's rare-earth production, consumption, and reserves and the important policies and regulations regarding the production and trade of rare earths, including recently announced export quotas. The 15 lanthanide elements-lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium (atomic numbers 57-71)-were originally known as the rare earths from their occurrence in oxides mixtures. Recently, some researchers have included two other elements-scandium and yttrium-in their discussion of rare earths. Yttrium (atomic number 39), which lies above lanthanum in transition group III of the periodic table and has a similar 3+ ion with a noble gas core, has both atomic and ionic radii similar in size to those of terbium and dysprosium and is generally found in nature with lanthanides. Scandium (atomic number 21) has a smaller ionic radius than yttrium and the lanthanides, and its chemical behavior is intermediate between that of aluminum and the lanthanides. It is found in nature with the lanthanides and yttrium. Rare earths are used widely in high-technology and clean-energy products because they impart special properties of magnetism, luminescence, and strength. Rare earths are also used in weapon systems to obtain the same properties.

  8. Phase stable rare earth garnets

    Kuntz, Joshua D.; Cherepy, Nerine J.; Roberts, Jeffery J.; Payne, Stephen A.


    A transparent ceramic according to one embodiment includes a rare earth garnet comprising A.sub.hB.sub.iC.sub.jO.sub.12, where h is 3.+-.10%, i is 2.+-.10%, and j is 3.+-.10%. A includes a rare earth element or a mixture of rare earth elements, B includes at least one of aluminum, gallium and scandium, and C includes at least one of aluminum, gallium and scandium, where A is at a dodecahedral site of the garnet, B is at an octahedral site of the garnet, and C is at a tetrahedral site of the garnet. In one embodiment, the rare earth garment has scintillation properties. A radiation detector in one embodiment includes a transparent ceramic as described above and a photo detector optically coupled to the rare earth garnet.

  9. Recent development in clusters of rare earths and actinides. Chemistry and materials

    Zheng, Zhiping (ed.) [Arizona Univ., Tucson, AZ (United States). Dept. of Chemistry and Biochemistry


    This book contains the following eight contributions: 1. Lanthanide Hydroxide Cluster Complexes via Ligand-Controlled Hydrolysis of the Lanthanide Ions (Zhonghao Zhang, Yanan Zhang, and Zhiping Zheng); 2. Synthesis and Structures of Lanthanide-Transition Metal Clusters (Xiu-Ying Zheng, Xiang-Jian Kong, and La-Sheng Long); 3. Hydrothermal Synthesis of Lanthanide and Lanthanide-Transition-Metal Cluster Organic Frameworks via Synergistic Coordination Strategy (Jian-Wen Cheng and Guo-Yu Yang); 4. Oxo Clusters of 5f Elements (Sarah Hickam and Peter C.); 5. Construction and Luminescence Properties of 4f and d-4f Clusters with Salen-Type Schiff Base Ligands (Xiaoping Yang, Shiqing Wang, Chengri Wang, Shaoming Huang, and Richard A.); 6. 4f-Clusters for Cryogenic Magnetic Cooling (Yan-Cong Chen, Jun-Liang Liu, and Ming-Liang Tong); 7. Lanthanide Clusters Toward Single-Molecule Magnets (Tian Han, You-Song Ding, and Yan-Zhen Zheng); 8. Molecular Rare Earth Hydride Clusters (Takanori Shima and Zhaomin Hou).

  10. Influence of Doping Rare Earth on Performance of Lithium Manganese Oxide Spinels as Cathode Materials for Lithium-Ion Batteries

    Tang Zhiyuan; Zhang Na; Lu Xinghe; Huang Qinghua


    Some rare earth doping spinel LiMn2-xRExO4 (RE=La, Ce, Nd) cathode materials for lithium ion batteries were synthesized by the solid-state reaction method. The structure characteristics of these produced samples were investigated by XRD, SEM, and particle size distribution analysis. According to the microstructure and charge-discharge testing, the effect of doping rare earth on stabilizing the spinel structure was analyzed. Through a series of doping experiments, it is shown that when the doping content x within the range of 0.01~0.02 the cycle performance of the materials is greatly improved. The discharge capacity of the sample LiMn1.98La0.02O4, LiMn1.98Ce0.02O4 and LiMn1.98Nd0.02O4 remain 119.1, 114.2 and 117.5 mAh*g-1 after 50 cycles.

  11. China Rare Earth Holdings Limited


    China Rare Earth Holdings Limited is a large trans-area corporation and a public company listed in Hong Kong Stock Exchange (Name: China Rare Earth, Code: 0769), with headquarter in Hong Kong. Located on the bank of beautiful Taihu Lake, the subsidiary in Yinxing covers area of 200,000 m2. It has nearly 1,000 employees, 30% of whom are technical staffs. After self-administration and effort, the company passed ISO 9001: 2000 and ISO 14000 Certificaitons.

  12. China Rare Earth Market Review


    Rare earth market remained depressed after the New Year affected by the weak demand. Purchaser preferred to consume inventories rather than increase the stockpile. There was a strong wait-and-see atmosphere in the market. Driven by the intense desire to sell out the commodities, traders further decreased their quoted price for rare earth products. Most persons in the market preferred to hold commodities and waited for a rise in the market after the Spring Festival.

  13. China rare earth market review


    March 21-31,2012 Rare earth market rebounded holistically recently. Price of didymium products rose slightly after being stable for one month. There were also increases in the prices of europium oxide and terbium oxide, which led to a rush by phosphor plants. The market of yttrium-medium and europium-rich minerals remained stagnant though the rare earth market recovered. Price of the mineral was around RMB ¥210,000-250,000/ton.

  14. China Rare Earth Market Review


    November 20-30.2011 Weak demand resulted in the slack rare market. Consumers did not intend to rep earth enish inventories yet and transactions of rare earth products were stagnant. The market of didymium-related products was in the doldrums. Demand for dysprosium-related products was sluggish. Inquiries for europium oxide (99.9%) were few and dealings of the product were difficult.

  15. Effect of rare earth ions doping on properties of LiFePO4/C cathode material

    王丽; 焦昌梅; 梁广川; 赵南南; 王亚勉; 李琳慈


    LiFe0.99RE0.01PO4/C cathode material was synthesized by solid-state reaction method using FeC2O4·2H2O, Li2CO3, NH4H2PO4, RE(NO3)3·nH2O as raw materials and glucose as a carbon source. The doping effects of rare earth ions, such as La3+, Ce3+, Nd3+, on the structure and electrochemical properties of LiFePO4/C cathode material were systematically investigated. The as-prepared samples were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and particle size analysis. The electrochemical properties were investigated in terms of constant-current charge/discharge cycling tests.The XRD results showed that the rare earth ions doping did not change the olivine structure of LiFePO4, and all the doped samples were of single-phase with high crystallinity. SEM and particle size analysis results showed that the doping of La3+, Ce3+ and Nd3+ led to the decrease of particle size. The electrochemical results exhibited that the doping of La3+ and Ce3+ could improve the high-rate capability of LiFePO4/C cathode material, among which, the material doped with 1% Ce3+ exhibited the optimal elec-trochemical properties, whose specific discharge capacities could reach 128.9, 119.5 and 104.4 mAh/g at 1C, 2C and 5C rates, re-spectively.

  16. Rare Earth Elements-Doped LiCoO2 Cathode Material for Lithium-Ion Batteries

    魏进平; 曹晓燕; 潘桂玲; 叶茂; 阎杰


    Some compounds of LiCo1-xRExO2 (RE=rare earth elements and x=0.01~0.03) were prepared by doping rare earth elements to LiCoO2 via solid state synthesis. The microstructure characteristics of the LiCo1-xRExO2 were investigated by XRD. It was found that the lattice parameters c are increased and the lattice volumes are enlarged compared to that of LiCoO2. Moreover, the performance of LiCo1-xRExO2 as the cathode material in lithium ion battery is improved, especially LiCo1-xYxO2 and LiCo1-xLaxO2. The initial charge/discharge capacities of LiCo0.99Y0.01O2 and LiCo0.99La0.01O2 are 174/154 (mAh*g-1) and 159/149 (mAh*g-1) respectively, while those for LiCoO2 working in the same way are only 139/131 (mAh*g-1).

  17. Preparation, structure and catalytic performances of rare earth catalytic materials%稀土催化材料的制备、结构及催化性能

    詹望成; 郭耘; 郭杨龙; 龚学庆; 王艳芹; 卢冠忠


    The research and development of rare earth catalytic materials will greatly promote the high-efficiency utilization of abundant rare earth elements, such as La and Ce. Rare earth elements have under-filled 4f orbits and lanthanide contraction, resulting in their unique catalytic performances when used as an active component or the carrier of catalysts. This paper reviews the progress in the preparation, structural and catalytic properties of rare earth catalytic materials, containing rare earth oxides, rare earth composite oxides, rare earth-noble metal catalysts and rare earth modified porous materials. The effects of rare earth elements on the structures, activities and stabilities of the concerned catalysts are mainly described. As well as, the interactions between rare earth metals and transition metals or noble metals are also elaborated, which are critical for the performances of the catalysts. Finally, the development thinking for rare earth catalytic materials is put forwarded and outlooked.%稀土催化材料的研究和发展为La和Ce等高丰度轻稀土元素的高质、高效利用提供了有效的途径.稀土元素具有未充满电子的4f轨道和镧系收缩等特征,作为催化剂的活性组分或载体使用时表现出独特的催化性能.本文从稀土氧化物、稀土复合氧化物、稀土-贵金属催化剂、稀土改性多孔催化材料等稀土催化材料出发,重点介绍和讨论了稀土的添加对催化剂的结构、活性和稳定性等的影响,阐述了稀土与过渡金属及氧化物、稀土与贵金属之间的相互作用,及对催化剂催化性能的影响.并对稀土催化材料的研究和发展提出了思考和展望.

  18. Rare Earth Separation in China


    During the last decade, China rare earth (RE) industry has made significant progress and become one of the most important producers in the world. In this paper, the recent developments in both fundamental research and industrial application are briefly reviewed: (1) the development and application of Theory of Countercurrent Extraction, (2) the novel solvent extraction process and its application in industry for separating heavy rare earth elements (Tm, Yb, Lu), yttrium (Y), and scandium (Sc), (3) the on-line analysis and automatic control of countercurrent extraction, (4) the eco-friendly process for RE/Th separation of bastnasite in Sichuan Province and electrochemical process for Eu/RE separation, and (5) the optimized flowcharts for typical rare earth minerals in China.

  19. Use of natural clays as sorbent materials for rare earth ions: Materials characterization and set up of the operative parameters.

    Iannicelli-Zubiani, Elena Maria; Cristiani, Cinzia; Dotelli, Giovanni; Gallo Stampino, Paola; Pelosato, Renato; Mesto, Ernesto; Schingaro, Emanuela; Lacalamita, Maria


    Two mineral clays of the montmorillonite group were tested as sorbents for the removal of Rare Earths (REs) from liquid solutions. Lanthanum and neodymium model solutions were used to perform uptake tests in order to: (a) verify the clays sorption capability, (b) investigate the sorption mechanisms and (c) optimize the experimental parameters, such as contact time and pH. The desorption was also studied, in order to evaluate the feasibility of REs recovery from waters. The adsorption-desorption procedure with the optimized parameters was also tested on a leaching solution obtained by dissolution of a dismantled NdFeB magnet of a hard-disk. The clays were fully characterized after REs adsorption and desorption by means of X-ray powder diffraction (XRPD) and X-ray photoelectron spectroscopy (XPS); the liquid phase was characterized via Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) analyses. The experimental results show that both clays are able to capture and release La and Nd ions, with an ion exchange mechanism. The best total efficiency (capture ≈ 50%, release ≈ 70%) is obtained when the uptake and release processes are performed at pH=5 and pH=1 respectively; in real leached scrap solutions, the uptake is around 40% but release efficiency is strongly decreased passing from a mono-ion system to a real system (from 80% to 5%). Furthermore, a strong matrix effect is found, with the matrix largely affecting both the uptake and the release of neodymium.

  20. Research into processes of production of hydrides of materials containing rare-earth metals and their corrosion

    Sofronov, V. L.; Kartashov, E. Y.; Molokov, P. B.; Zhiganov, A. N.; Kalaev, M. E.


    Production of permanent magnets on basis of rare earth elements (REE) is implemented by means of powder metallurgy, therefore a technologically important operation is the multistage mechanical crushing of materials to the extent of domains. The promising technique of crushing of magnetic materials is their consistent hydrogenation-dehydrogenation that allows obtaining nano-dispersed powders which are stable enough in air. Hydrogenation apparatuses, as opposed to conventional grinding machines, do not comprise motion works and their producing capacity is much higher. Hydrogenation process does not require any additional preparation of materials and it excludes undermilling and overmilling as well as material oxidation. The paper presents the results of investigation on the temperature effect on the hydrogenation process of Nd-Fe alloys. The study results on the corrosion stability of ligature hydrides under various conditions are also given. Kinetic parameters of the hydrogenation process of ligatures are determined. The phase composition of corrosion products is detected. Guidelines on hydride powder storage are given.

  1. China Rare Earth Market Review


    August 20-31, 2011 Rare earth market did not show the sign of picking-up and remained stagnant recently. Most suppliers continued to decrease their quoted price, but leading producers in northern and southern China did not adjust their quoted price. Most rare earth plants in southern China had not yet resumed production. Quoted price of didymium products swung and the quoted prices of dysprosium-related products were slipping affected by weak demand. Inquiries for europium oxide were decreasing affected by the slow phosphor market.

  2. MOCVD and ALD of rare earth containing multifunctional materials. From precursor chemistry to thin film deposition and applications

    Milanov, Andrian Petrov


    The present thesis deals with the development of metal-organic complexes of rare elements. They should be used as novel precursors for the production of rare earth thin films by metal-organic chemical vapor deposition (MOCVD) and Atomic Layer Deposition (ALD). Within the work two precursor classes were examined, the tris-Malonato-complexes as well as the tris-Guanidinato-complexes of a series of rare earth metals. The latter showed excellent properties regarding to their volatility, their thermal stability, the defined decomposition and high reactivity towards water. They have been successfully used as precursors for the MOCVD of rare earth oxide layers. By using of a gadolinium guanidinate it could also be shown that the rare earth guanidinates are promising precursors for ALD of rare earth oxide and MOCVD of rare earth nitride layers. [German] Die vorliegende Dissertation beschaeftigt sich mit der Entwicklung von metallorganischen Komplexen der Seltenerd-Elemente. Diese sollten als neuartigen Precursoren fuer die Erzeugung von seltenerdhaltigen Duennschichten mittels Metallorganischer Chemischer Dampfabscheidung (MOCVD) und Atomic Layer Deposition (ALD) eingesetzt werden. Innerhalb der Arbeit wurden zwei Precursorklassen untersucht, die Tris-Malonato-Komplexe sowie die Tris-Gunanidinato-Komplexe einer Reihe von Seltenerdmetallen. Letztere zeigten hervorragende Eigenschaften bezueglich ihrer Fluechtigkeit, ihrer thermischen Stabilitaet, der definierten Zersetzung und der hohen Reaktivitaet gegenueber Wasser. Sie wurden erfolgreich als Precursoren fuer die MOCVD von Seltenerd-Oxid-Schichten eingesetzt. Unter Verwendung eines Gadolinium Guanidinats konnte ausserdem gezeigt werden, dass die Seltenerd-Guanidinate vielversprechende Precursoren fuer die ALD von Seltenerd-Oxid-Schichten sowie die MOCVD von Seltenerd-Nitrid-Schichten darstellen.

  3. Development Trend of Rare Earth Standardion Work

    Ma Jie; Lin Jirong; Zhao Fei; Zhang Xiuyan


    Rare earth standardization was developed along with rare earth industry.In recent decades, great advances have been made in China rare earth industry.This paper describes the status of rare earth standardization, problems existed and ways to perfect.Now the number of Chinese Rare Earth Standards has increased to 232 with expanding of the categories and covering scope of rare earth products.But the present standard system cannot be completely suited with rare earth production and trade, and not keep pace with the advance of technology.Standards are important rules in world trade and must be acted on.

  4. Effect of Rare Earth Elements (Er, Ho) on Semi-Metallic Materials (ScN) in an Applied Electric Field

    Kim, Hyunjung; Park, Yeonjoon; King, Glen C.; Lee, Kunik; Choi, Sang H.


    The development of materials and fabrication technology for field-controlled spectrally active optics is essential for applications such as membrane optics, filters for LIDARs, windows for sensors, telescopes, spectroscopes, cameras and flat-panel displays. The dopants of rare earth elements, in a host of optical systems, create a number of absorption and emission band structures and can easily be incorporated into many high quality crystalline and amorphous hosts. In wide band-gap semiconductors like ScN, the existing deep levels can capture or emit the mobile charges, and can be ionized with the loss or capture of the carriers which are the fundamental basis of concept for smart optic materials. The band gap shrinkage or splitting with dopants supports the possibility of this concept. In the present work, a semi-metallic material (ScN) was doped with rare earth elements (Er, Ho) and tested under an applied electric field to characterize spectral and refractive index shifts by either Stark or Zeeman Effect. These effects can be verified using the UV-Vis spectroscopy, the Hall Effect measurement and the ellipsometric spectroscopy. The optical band gaps of ScN doped with Er and doped with Ho were experimentally estimated as 2.33eV and 2.24eV ( 0.2eV) respectively. This is less than that of undoped ScN (2.5 0.2eV). The red-shifted absorption onset is a direct evidence for the decrease of band gap energy (Eg), and the broadening of valence band states is attributable to the doping cases. A decrease in refractive index with an applied field was observed as a small shift in absorption coefficient using a variable angle spectroscopic ellipsometer. In the presence of an electric field, mobile carriers are redistributed within the space charge region (SCR) to produce this electro-refractive effect. The shift in refractive index is also affected by the density and location of deep potential wells within the SCR. In addition, the microstructure change was observed by a TEM

  5. China Rare Earth Market Review


    June 20-30, 2011 Prices of heavy rare earth products remained soaring. The same happened to dysprosium and its related products due to tight supply. Separation plants held tightly of europium oxide. Refining plants took a positive attitude toward the ma

  6. Rare earth doped nanoparticles in organic and inorganic host materials for application in integrated optics

    Dekker, R.; Hilderink, L.T.H.; Diemeer, Mart; Stouwdam, J.W.; Sudarsan, V; van Veggel, F.C.J.M.; Driessen, A.; Worhoff, Kerstin; Misra, D; Masscher, P.; Sundaram, K.; Yen, W.M.; Capobianco, J.


    The preparation and the optical properties of lanthanum fluoride (LaF3) nanoparticles doped with erbium and neodymium will be discussed. Organic and inorganic materials in the form of polymers and sol-gels were used to serve as the hosts for the inorganic nanoparticles, respectively. The organic

  7. Comprehensive Recycling of the Abandoned Rare Earth Functional Materials%废弃稀土功能材料的综合回收利用

    张博; 王威; 高照国


    China possesses the most abundant rare earth resources of the world .In recent years,as the increase of consumption demand and the long -term predatory exploitation,the reserves of the rare earth rapidly declined .The abandoned rare earth functional materials contain large amounts rare earth metals and other valuable elements .Therefore ,the efficiently clean utilization of the aban-doned rare earth functional materials is an important way to ease the contradiction between the sup-ply and demand of the rare earth resources .In this paper,the comprehensive utilization process of the rare earth permanent magnet materials , the rare earth hydrogen storage materials and the rare earth phosphor materials were reviewed .Based on the comparative analysis of the advantages and disadvantages of the different processes , a number of advises to solve the existing problems were proposed .%中国稀土储量居世界第一位,但随着稀土需求量的增加以及长期以来稀土资源掠夺式开采等因素的影响,我国稀土储量锐减。废弃稀土功能材料含有大量的稀土和其他有价金属元素,因此,对废弃稀土功能材料进行高效清洁利用是缓解我国稀土资源供需矛盾的重要途径。对稀土永磁材料、稀土储氢材料、稀土荧光粉材料等废弃稀土功能材料的综合利用工艺进行了综述,在比较不同工艺优缺点的基础上提出了一些解决现存问题的建议。

  8. RE Advanced Materials Pushing the Development of Chinese Rare Earth Industry (Continued)

    ZHAO Zengqi


    @@ 2.3 Unbalanced production and sales will be worsened There is still diversity of the demand for various RE products in the following few years.Especially,fast development of NdFeB permanent magnetic materials worsens the unbalanced situation of RE market.Besides,with the development of science and technology,some traditional RE applications are challenged by new technology or new products.

  9. Numerical Research of Materials Crystal Lattice Parameters Based on Rare-Earth Metals

    Obkhodsky Artem


    Full Text Available Geometrical parameters (coordinates and angles of CeO2 crystal lattice by molecular dynamics method are calculated. Calculated parameters of crystal lattice are applied for definition the energy band structure via Hartree-Fock method in an approximation to CO LCAO (crystal orbitals as linear combination of atomic orbitals and using the model of cyclic cluster. Calculated minimum energy band p-d is within the value range of experimental data. Valence band maximum is 4.2 while minimum energy band p-d width is 2.8 eV Quantum-chemical calculations are accelerated by Schwarz inequality and direct inversion method in iterative subspace. The obtained mathematical model is implemented into software package for calculating material properties.

  10. Novel indicators for the quantification of resilience in critical material supply chains, with a 2010 rare earth crisis case study.

    Sprecher, Benjamin; Daigo, Ichiro; Spekkink, Wouter; Vos, Matthijs; Kleijn, Rene; Murakami, Shinsuke; Kramer, Gert Jan


    We introduce several new resilience metrics for quantifying the resilience of critical material supply chains to disruptions, and validate these metrics using the 2010 rare earth element (REE) crisis as a case study. Our method is a novel application of Event Sequence Analysis, supplemented with interviews of actors across the entire supply chain. We discuss resilience mechanism in quantitative terms - time lags, response speeds and maximum magnitudes - and in light of cultural differences between Japanese and European corporate practice. This quantification is crucial if resilience is ever to be taken into account in criticality assessments, and a step towards determining supply and demand elasticities in the REE supply chain. We find that the REE system showed resilience mainly through substitution and increased non-Chinese primary production, with a distinct role for stockpiling. Overall, annual substitution rates reached 10% of total demand. Non-Chinese primary production ramped up at a speed of 4% of total market volume per year. The compound effect of these mechanism was that recovery from the 2010 disruption took two years. The supply disruption did not nudge a system towards an appreciable degree of recycling. This finding has important implications for the circular economy concept, indicating that quite a long period of sustained material constraints will be necessary for a production-consumption system to naturally evolve towards a circular configuration.

  11. Hydrodynamic resistance parameters for ErPr rare-earth regenerator material under steady and periodic flow conditions

    Pathak, M. G.; Helvensteijn, B. P.; Patel, V. C.; Ghiaasiaan, S. M.; Mulcahey, T. I.; Kashani, A.; Feller, J. R.


    The regenerator, typically a microporous structure that is subject to periodic flow of a cryogenic fluid, is a critical component of pulse tube or Stirling cryocoolers, which are widely used for high-demand aerospace and defense applications. In this investigation, experiments were conducted in which steady and oscillatory flows of helium were imposed on ErPr rare-Earth regenerator filler material and mass flow and pressure drop data were recorded under ambient temperature conditions. A computational fluid dynamics (CFD)-assisted method was applied for the analysis and interpretation of the experimental data. The permeability and inertial coefficients that lead to agreement between the experimental data and computational simulations were iteratively obtained. The Darcy permeability and Forchheimer inertial coefficients were obtained and were found to be functions of the system charge pressure, operating frequency, and compressor piston stroke within the studied range of interest. The results also exhibit that the periodic flow hydrodynamic resistance parameters are in general different than steady flow parameters.

  12. Rare Earths; The Fraternal Fifteen (Rev.)

    Gschneidner, Jr., Karl A. [Iowa State University; Ames Laboratory


    Rare earths are a set of 15 elements: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. They are not rare and not earths; they are metals and quite abundant. They are studied to develop commercial products which are beneficial to mankind, and because some rare earths are important to fission products.

  13. 2006 Rare Earth Export Quota


    @@ According to correlative stipulations in "Goods Import εt Export Administrating Statute of P.R.C", 2006export quota for important industrial products was issued by the Ministry of Commerce of P.R.C. on December 30th of 2005. Export quota of rare earth products is 45,000 tons. It is said the quota will be distributed in two batches. The first batch of quota will reach 70-80% of the total with 21,700 - 24,800tons for domestic companies and 10,500 - 12,000 tons for foreign invested companies. Quota will be distributed to relevant enterprises directly in recent days.

  14. Benefit of Rare-Earth "Smart Doping" and Material Nanostructuring for the Next Generation of Er-Doped Fibers

    Savelii, Inna; Bigot, Laurent; Capoen, Bruno; Gonnet, Cedric; Chanéac, Corinne; Burova, Ekaterina; Pastouret, Alain; El-Hamzaoui, Hicham; Bouazaoui, Mohamed


    Erbium-doped fiber amplifiers (EDFAs) for harsh environments require to develop specific fabrication methods of Er 3+-doped fibers (EDFs) so as to limit the impact of radiation-induced absorption. In this context, a compromise has to be found between the concentration of Erbium and the glass composition. On the one hand, high concentration of Er 3+ ions helps to reduce the length of the EDF and hence the cumulated attenuation but generally leads to luminescence quenching mechanisms that limit the performances. On the other hand, so as to avoid such quenching effect, glass modifiers like Al 3+ or P 5+ ions are used in the fabrication of commercial EDFs but are not suitable for applications in harsh environment because these glass modifiers are precursors of radiation-induced structural defects and consequently of optical losses. In this work, we investigate the concept of smart doping via material nanostructuring as a way to fabricate more efficient optical devices. This approach aims at optimizing the glass composition of the fiber core in order to use the minimal content of glass modifiers needed to reach the suited level of performances for EDFA. Er 3+-doped alumina nanoparticles (NPs), as precursor of Er 3+ ions in the preform fabrication process, were used to control the environment of rare-earth ions and their optical properties. Structural and optical characterizations of NP-doped preforms and optical fibers drawn from such preforms demonstrate the interest of this approach for small concentrations of aluminum in comparison to similar glass compositions obtained by a conventional technique.

  15. Benefit of Rare-Earth "Smart Doping" and Material Nanostructuring for the Next Generation of Er-Doped Fibers.

    Savelii, Inna; Bigot, Laurent; Capoen, Bruno; Gonnet, Cedric; Chanéac, Corinne; Burova, Ekaterina; Pastouret, Alain; El-Hamzaoui, Hicham; Bouazaoui, Mohamed


    Erbium-doped fiber amplifiers (EDFAs) for harsh environments require to develop specific fabrication methods of Er (3+)-doped fibers (EDFs) so as to limit the impact of radiation-induced absorption. In this context, a compromise has to be found between the concentration of Erbium and the glass composition. On the one hand, high concentration of Er (3+) ions helps to reduce the length of the EDF and hence the cumulated attenuation but generally leads to luminescence quenching mechanisms that limit the performances. On the other hand, so as to avoid such quenching effect, glass modifiers like Al (3+) or P (5+) ions are used in the fabrication of commercial EDFs but are not suitable for applications in harsh environment because these glass modifiers are precursors of radiation-induced structural defects and consequently of optical losses. In this work, we investigate the concept of smart doping via material nanostructuring as a way to fabricate more efficient optical devices. This approach aims at optimizing the glass composition of the fiber core in order to use the minimal content of glass modifiers needed to reach the suited level of performances for EDFA. Er (3+)-doped alumina nanoparticles (NPs), as precursor of Er (3+) ions in the preform fabrication process, were used to control the environment of rare-earth ions and their optical properties. Structural and optical characterizations of NP-doped preforms and optical fibers drawn from such preforms demonstrate the interest of this approach for small concentrations of aluminum in comparison to similar glass compositions obtained by a conventional technique.

  16. Rare-earth oxide nanostructures: rules of rare-earth nitrate thermolysis in octadecylamine.

    Wang, Dingsheng; Wang, Zhongying; Zhao, Peng; Zheng, Wen; Peng, Qing; Liu, Liqin; Chen, Xueyuan; Li, Yadong


    The decomposed regularity of rare-earth nitrates in octadecylamine (ODA) is discussed. The experimental results show that these nitrates can be divided into four types. For rare-earth nitrates with larger RE(3+) ions (RE=rare earth, La, Pr, Nd, Sm, Eu, Gd), the decomposed products exhibited platelike nanostructures. For those with smaller RE(3+) ions (RE=Y, Dy, Ho, Er, Tm, Yb), the decomposed products exhibited beltlike nanostructures. For terbium nitrate with a middle RE(3+) ion, the decomposed product exhibited a rodlike nanostructure. The corresponding rare-earth oxides, with the same morphologies as their precursors, could be obtained when these decomposed products were calcined. For cerium nitrate, which showed the greatest differences, flowerlike cerium oxide could be obtained directly from decomposition of the nitrate without further calcination. This regularity is explained on the basis of the lanthanide contraction. Owing to their differences in electron configuration, ionic radius, and crystal structure, such a nitrate family therefore shows different thermolysis properties. In addition, the potential application of these as-obtained rare-earth oxides as catalysts and luminescent materials was investigated. The advantages of this method for rare-earth oxides includes simplicity, high yield, low cost, and ease of scale-up, which are of great importance for their industrial applications.

  17. Visualizing Earth Materials

    Cashman, K. V.; Rust, A.; Stibbon, E.; Harris, R.


    Earth materials are fundamental to art. They are pigments, they are clay, they provide form and color. Earth scientists, however, rarely attempt to make the physical properties of Earth materials visible through art, and similarly many artists use Earth materials without fully understanding their physical and chemical properties. Here we explore the intersection between art and science through study of the physical properties of Earth materials as characterized in the laboratory, and as transferred to paper using different techniques and suspending media. One focus of this collaboration is volcanic ash. Ash is interesting scientifically because its form provides information on the fundamental processes that drive volcanic eruptions, and determines its transport properties, and thus its potential to affect populations far downwind of the volcano. Ash properties also affect its behavior as an art material. From an aesthetic point of view, ash lends a granular surface to the image; it is also uncontrollable, and thus requires engagement between artist and medium. More fundamentally, using ash in art creates an exchange between the medium and the subject matter, and imparts something of the physical, visceral experience of volcanic landscapes to the viewer. Another component of this work uses powdered rock as a printing medium for geologic maps. Because different types of rock create powders with different properties (grain size distributions and shapes), the geology is communicated not only as color, but also by the physical characteristics of the material as it interacts with the paper. More importantly, the use of actual rocks samples as printing material for geologic maps not only makes a direct connection between the map and the material it represents, but also provides an emotional connection between the map, the viewer and the landscape, its colors, textures and geological juxtapositions. Both case studies provide examples not only of ways in which artists can

  18. Rare-Earth-Free Traction Motor: Rare Earth-Free Traction Motor for Electric Vehicle Applications



    REACT Project: Baldor will develop a new type of traction motor with the potential to efficiently power future generations of EVs. Unlike today’s large, bulky EV motors which use expensive, imported rare-earth-based magnets, Baldor’s motor could be light, compact, contain no rare earth materials, and have the potential to deliver more torque at a substantially lower cost. Key innovations in this project include the use of a unique motor design, incorporation of an improved cooling system, and the development of advanced materials manufacturing techniques. These innovations could significantly reduce the cost of an electric motor.

  19. Earth materials and earth dynamics

    Bennett, K; Shankland, T. [and others


    In the project ''Earth Materials and Earth Dynamics'' we linked fundamental and exploratory, experimental, theoretical, and computational research programs to shed light on the current and past states of the dynamic Earth. Our objective was to combine different geological, geochemical, geophysical, and materials science analyses with numerical techniques to illuminate active processes in the Earth. These processes include fluid-rock interactions that form and modify the lithosphere, non-linear wave attenuations in rocks that drive plate tectonics and perturb the earth's surface, dynamic recrystallization of olivine that deforms the upper mantle, development of texture in high-pressure olivine polymorphs that create anisotropic velocity regions in the convecting upper mantle and transition zone, and the intense chemical reactions between the mantle and core. We measured physical properties such as texture and nonlinear elasticity, equation of states at simultaneous pressures and temperatures, magnetic spins and bonding, chemical permeability, and thermal-chemical feedback to better characterize earth materials. We artificially generated seismic waves, numerically modeled fluid flow and transport in rock systems and modified polycrystal plasticity theory to interpret measured physical properties and integrate them into our understanding of the Earth. This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL).

  20. The Chinese Society of Rare Earth is Studying The Feasibility of Marketing Rare Earth Futures


    Lin Donglu,secretary-general of the Chinese Society of Rare Earth recently said,the Chinese Society of Rare Earth undertook the research on subject of the National Social Science Fund Foundation on the reform of Chinese rare earth trading pricing mechanism on promoting RMB globalization,and is focusing on studying the feasibility of marketing rare earth futures variety.

  1. Analysis and Outlook of Global Rare Earth Market

    XIONG Jiaqi


    @@ When enterd into 21st century,global rare earth market exhibits pleasing situation in recent years,profitig from fast development of global economy.China represented nearly 60% of global rare earth consumption in 2007.Rare earth consumtion in five advanced materisls including permanent magnets,polishing powder,hydrogen storage materisls,fluorescent materials and auto catalysts accounted for 60% of the tutal consumption.

  2. Rare earth elements: end use and recyclability

    Goonan, Thomas G.


    Rare earth elements are used in mature markets (such as catalysts, glassmaking, lighting, and metallurgy), which account for 59 percent of the total worldwide consumption of rare earth elements, and in newer, high-growth markets (such as battery alloys, ceramics, and permanent magnets), which account for 41 percent of the total worldwide consumption of rare earth elements. In mature market segments, lanthanum and cerium constitute about 80 percent of rare earth elements used, and in new market segments, dysprosium, neodymium, and praseodymium account for about 85 percent of rare earth elements used. Regardless of the end use, rare earth elements are not recycled in large quantities, but could be if recycling became mandated or very high prices of rare earth elements made recycling feasible.

  3. Rare earths & climate change,new energy,energy conservation and pollution reduction(continued)


    @@ Ⅲ.Contribution of rare earths to energy conservation Rechargeable batteries and rare earth permanent magnetic motor matching with batteries in every Prius car consume approximately 10 kg of rare-earth hydro-gen storage materials and 2 kg of rare earth permanent magnetic materials respectively.

  4. Replacing the Rare Earth Intellectual Capital

    Gschneidner, Jr., Karl


    personnel to bring the entire rare earth industry, from mining to original equipment manufacturers (OEM), up to full speed in the next few years. Accompanying this decline in technical expertise, innovation and new products utilizing rare earth elements has slowed dramatically, and it may take a decade or more to recapture America's leading role in technological advancements of rare earth containing products. Before the disruption of the US rare earth industry, about 25,000 people were employed in all aspects of the industry from mining to OEM. Today, only about 1,500 people are employed in these fields. The ratio of non-technically trained persons to those with college degrees in the sciences or engineering varies from about 8 to 1 to about 4 to 1, depending on the particular area of the industry. Assuming an average of 6 to 1, the number of college degree scientists and engineers has decreased from about 4,000 to 250 employed today. In the magnetic industry the approximate numbers are: 6,000 total with 750 technically trained people in the 1980s to 500 totally employed today of which 75 have degrees. The paucity of scientists and engineers with experience and/or training in the various aspects of production and commercialization of the rare earths is a serious limitation to the ability of the US to satisfy its own needs for materials and technologies (1) to maintain our military strength and posture, (2) to assume leadership in critical energy technologies, and (3) to bring new consumer products to the marketplace. The lack of experts is of even greater national importance than the halting in the 1990s and the recent restart of the mining/benification/separation effort in the US; and thus governmental intervention and support for at least five to 10 years will be required to ameliorate this situation. To respond quickly, training programs should be established in conjunction with a national research center at an educational institution with a long tradition in

  5. Rare earth metal doped CeO2-based catalytic materials for diesel soot oxidation at lower temperatures

    A Rangaswamy; Putla Sudarsanam; Benjaram M Reddy


    In this work, the influence of trivalent rare-earth dopants (Sm and La) on the structure-activity properties of CeO2 was thor-oughly studied for diesel soot oxidation. For this, an optimized 40%of Sm and La was incorporated into the CeO2 using a facile co-precipitation method from ultra-high dilute aqueous solutions. A systematic physicochemical characterization was carried out using X-ray diffraction (XRD), transmission electron microscopy (TEM), Brumauer-Emmett-teller method (BET) surface area, X-ray pho-toelectron spectroscopy (XPS), Raman, and H2-temperature programmed reduction (TPR) techniques. The soot oxidation efficiency of the catalysts was investigated using a thermogravimetric method. The XRD results suggested the formation of nanocrystalline sin-gle phase CeO2-Sm2O3 and CeO2-La2O3 solid solutions. The Sm-and La-doped CeO2 materials exhibited smaller crystallite size and higher BET surface area compared with the pure CeO2. Owing to the difference in the oxidation states of the dopants (Sm3+and La3+) and the Ce4+, a number of oxygen vacancies were generated in CeO2-Sm2O3 and CeO2-La2O3 samples. The H2-TPR studies evidenced the improved reducible nature of the CeO2-Sm2O3 and CeO2-La2O3 samples compared with the CeO2. It was found that the addition of Sm and La to the CeO2 outstandingly enhanced its catalytic efficiency for the oxidation of diesel soot. The observed 50%soot con-version temperatures for the CeO2-Sm2O3, CeO2-La2O3 and CeO2 were~790, 843 and 864 K (loose contact), respectively, and similar activity order was also found under the tight contact condition. The high soot oxidation efficacy of the CeO2-Sm2O3 sample was at-tributed to numerous catalytically favourable properties, like smaller crystallite size, larger surface area, abundant oxygen vacancies, and superior reducible nature.

  6. Characterization and recovery of rare earth elements from electronic scrap

    Bristøl, Lene Marie Lysgaard


    The rare earth elements are a group of 17 elements consisting of the lantahnide series, scandium and yttrium. The application with the largest rare earth consumption is the permanent rare earth magnets. The neodymium-iron-boron magnets are the strongest permanent magnetic material known and are widely used. There is a concern that there will be a shortage in Nd-Fe-B magnets in short time. This has lead to an increased interest in the recycling of the rare earth magnets in the world.This proje...

  7. 稀土催化材料的应用及研究进展%Current status and perspectives of rare earth catalytic materials and catalysis

    詹望成; 郭耘; 龚学庆; 郭杨龙; 王艳芹; 卢冠忠


    Rare earth elements possess 4f orbitals without full electron occupancy and lanthanide contraction. This characteristic results in their unique catalytic performance when they are used as active com-ponents or as catalyst supports. Research into and the development of rare earth catalytic materials will significantly promote the high-efficiency utilization of abundant rare earth elements, such as lanthanum and cerium. Currently, rare earth catalytic materials play an important role in such areas as the petroleum chemical industry, the catalytic combustion of fossil fuels, automotive emissions control, the purification of industrial waste air, and solid solution fuel cells. In this paper, we review the application of and recent research progress that has been made on rare earth catalytic materials, including relative theoretical research. The effects of rare earth elements on the structure, activity, and stability of the catalysts of interest are described.%稀土元素具有未充满电子的4f轨道和镧系收缩等特征,当用作催化剂的活性组分或载体时常常表现出独特的催化性能。稀土催化材料的研究和发展为La和Ce等高丰度轻稀土元素的高质、高效利用提供了有效的途径。目前稀土催化材料在石油化工、化石燃料的催化燃烧、机动车尾气净化、工业废气治理和固体氧化物燃料电池等领域发挥着重要的作用。本文综述了稀土催化材料的应用以及理论研究进展,重点讨论了稀土元素对所涉及催化剂的结构、活性和稳定性等的影响。

  8. Funing Rare Earths Industrial Co. Ltd


    The company covers separation with whole lines of light, medium and heavy rare earths, with annual separation volume of rare earth oxides of 4,500 tons. It also produces rare earth oxides, fluorides and salts. Products with high-purity and super-high-purity are produced according to customer's request. Under the technological guidance of domestic experts and application of modern high-pressure

  9. Anthropogenic Cycles of Rare Earth Elements

    Du, X.; Graedel, T. E.


    This research will develop quantitatively resolved anthropogenic cycles and in-use stocks for the rare earth metals specifically cerium, lanthanum and dysprosium in Japan, China, and the U.S. for the year of 2007. Rare earth elements (REE) is a group of 17 scare metals widely used in a growing number of emerging technologies and have been in high demand for emerging technologies as raw materials during past the three decades. New market participants from newly industrializing countries, primarily China, have had strong impacts on the demand of share. Consequently, the importance to sustain a reliable, steady, uninterrupted supply on global market triggered comprehensive research to recognize and understand the life cycles of rare earths. Moreover, because China plays a dominant role in mining production since 1990, it requires the assessment for the countries, which are almost completely dependent on imports from China with respect to rare earth resources. The study aims to analyze the flows and stocks of rare earth elements individually as elemental form in spite of their natural geological co-occurrence and mixed composition in applications. By applying the method of Material Flow Analysis (MFA) work has been done on evaluating current and historical flows of specific technologically significant materials, for example, copper, zinc, nickel, etc., determining the stocks available in different types of reservoirs (e.g., lithosphere, in-use) and the flows among the reservoirs, developing scenarios of possible futures of metal use, and assessing the environmental and policy implications of the results. Therefore, REE as a new target deserves inclusion because of its potential demand-supply conflict and importance to secure the competitive advantage of technical innovation in future. This work will generate a quantitatively resolved anthropogenic life cycle and in-use stocks for REE for the main target countries for a chosen year, 2007, providing flows and stocks from

  10. Opinions on hot discussions in connection with rare earths recently (continued)


    @@ IV.Rare earths are mostly for civil uses Rare earth elements have excellent physical properties including optical, electric, magnetic, superconductive and catalytic performances and outstanding .chemical properties.The value of rare earths is mostly embodied in their applications.Rare earths are prepared into various advanced materials with different performances.Therefore, rare earths enjoy the reputation of "industrial monosodium glutamate" and "treasury of advanced materials".

  11. Rare-Earth-Free Permanent Magnets for Electrical Vehicle Motors and Wind Turbine Generators: Hexagonal Symmetry Based Materials Systems Mn-Bi and M-type Hexaferrite

    Hong, Yang-Ki [University of Alabama; Haskew, Timothy [University of Alabama; Myryasov, Oleg [University of Alabama; Jin, Sungho [University of California San Diego; Berkowitz, Ami [University of California San Diego


    The research we conducted focuses on the rare-earth (RE)-free permanent magnet by modeling, simulating, and synthesizing exchange coupled two-phase (hard/soft) RE-free core-shell nano-structured magnet. The RE-free magnets are made of magnetically hard core materials (high anisotropy materials including Mn-Bi-X and M-type hexaferrite) coated by soft shell materials (high magnetization materials including Fe-Co or Co). Therefore, our research helps understand the exchange coupling conditions of the core/shell magnets, interface exchange behavior between core and shell materials, formation mechanism of core/shell structures, stability conditions of core and shell materials, etc.

  12. Recycling of Rare Earth Elements

    Lorenz, Tom; Bertau, Martin


    Any development of an effective process for rare earth (RE) recycling has become more and more challenging, especially in recent years. Since 2011, when commodity prices of REs had met their all-time maximum, prices have dropped rapidly by more than 90 %. An economic process able to offset these fluctuations has to take unconventional methods into account beside well-known strategies like acid/basic leaching or solvent extraction. The solid-state chlorination provides such an unconventional method for mobilizing RE elements from waste streams. Instead of hydrochloric acid this kind of chlorination decomposes NH4Cl thermally to release up to 400 °C hot HCl gas. After cooling the resulting solid metal chlorides may be easily dissolved in pH-adjusted water. Without producing strongly acidic wastes and with NH4Cl as cheap source for hydrogen chloride, solid-state chlorination provides various advantages in terms of costs and disposal. In the course of the SepSELSA project this method was examined, adjusted and optimized for RE recycling from fluorescent lamp scraps as well as Fe14Nd2B magnets. Thereby many surprising influences and trends required various analytic methods to examine the reasons and special mechanisms behind them.

  13. Global rare earth resources and scenarios of future rare earth industry

    CHEN Zhanheng


    It is known to all that China is abundant in rare earth resources. But rare earth deposits are really not that rare in the earth crust. In the five continents, i.e. Asia, Europe, Australia, North and South America, and Africa, there are about thirty four countries found to have rare earth deposits; Brazil might surpass China and rank the first in rare earth deposits. At present, investment in rare earth production was surged,there have been about 200 projects, and the total production for 25 of them would be more than 170 thousand tons after 2015, a multi-supply system on rare earths is being established worldwide. Cautions on the investment of rare earth production are involved.

  14. Rare earth elements and strategic mineral policy

    Kooroshy, J.; Korteweg, R.; Ridder, M. de


    Newspapers report almost daily on international tensions around ‘strategic’ or ‘critical’ minerals such as rare earth elements. The temporary freeze of rare earth exports from China to Japan in late 2010 in retaliation of the capture of a Chinese captain is but one example of the strategic use of no

  15. Thermal Stability and Proton Conductivity of Rare Earth Orthophosphate Hydrates

    Anfimova, Tatiana; Li, Qingfeng; Jensen, Jens Oluf


    Hydrated orthophosphate powders of three rare earth metals, lanthanum, neodymium and gadolinium, were prepared and studied as potential proton conducting materials for intermediate temperature electrochemical applications. The phosphates undergo a transformation from the rhabdophane structure...

  16. Chinalco Rare Earth has Surpassed Ganzhou to Become the Biggest Giant in South China Rare Earth


    As the pillar enterprise in Chinalco rare earth unit,Chinalco Guangxi Rare Earth Company firmly grasped the historical opportunity of the state government supporting six big groups including Chinalco to integrate and develop domestic rare earth enterprises,riding the east wind to stand out,recently,it made significant

  17. Rare Earth Metals: Resourcefulness and Recovery

    Wang, Shijie


    When we appreciate the digital revolution carried over from the twentieth century with mobile communication and the Internet, and when we enjoy our high-tech lifestyle filled with iDevices, hybrid cars, wind turbines, and solar cells in this new century, we should also appreciate that all of these advanced products depend on rare earth metals to function. Although there are only 136,000 tons of annual worldwide demand, (Cho, Rare Earth Metals, Will We Have Enough?)1 rare earth metals are becoming such hot commodities on international markets, due to not only to their increasing uses, including in most critical military hardware, but also to Chinese growth, which accounts for 95% of global rare earth metal production. Hence, the 2013 technical calendar topic, planned by the TMS/Hydrometallurgy and Electrometallurgy Committee, is particularly relevant, with four articles (including this commentary) contributed to the JOM October Issue discussing rare earth metals' resourcefulness and recovery.

  18. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman


    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) & 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) &29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of 232Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.

  19. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    AL-Areqi, Wadeeah M., E-mail:; Majid, Amran Ab., E-mail:; Sarmani, Sukiman, E-mail: [Nuclear Science Programme, School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi (Malaysia)


    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of {sup 232}Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.

  20. Rare-earth-ion-doped double-tungstate waveguides

    Pollnau, M.


    It has been recognized that the monoclinic double tungstates KY(WO4)2, KGd(WO4)2, and KLu(WO4)2 possess a high potential as rare-earth-ion-doped solid-state laser materials, partly due to the high absorption and emission cross-sections of rare-earth ions when doped into these materials. Besides, the

  1. Hydrophobicity of rare-earth oxide ceramics

    Azimi, Gisele; Dhiman, Rajeev; Kwon, Hyuk-Min; Paxson, Adam T.; Varanasi, Kripa K.


    Hydrophobic materials that are robust to harsh environments are needed in a broad range of applications. Although durable materials such as metals and ceramics, which are generally hydrophilic, can be rendered hydrophobic by polymeric modifiers, these deteriorate in harsh environments. Here we show that a class of ceramics comprising the entire lanthanide oxide series, ranging from ceria to lutecia, is intrinsically hydrophobic. We attribute their hydrophobicity to their unique electronic structure, which inhibits hydrogen bonding with interfacial water molecules. We also show with surface-energy measurements that polar interactions are minimized at these surfaces and with Fourier transform infrared/grazing-angle attenuated total reflection that interfacial water molecules are oriented in the hydrophobic hydration structure. Moreover, we demonstrate that these ceramic materials promote dropwise condensation, repel impinging water droplets, and sustain hydrophobicity even after exposure to harsh environments. Rare-earth oxide ceramics should find widespread applicability as robust hydrophobic surfaces.



    Full Text Available Results of development and certification of reference materials of composition of heat resisting nickel alloy with the certified values of content of detrimental impurities (Zn, Cd, Pb, Tl, Bi, In, Ag, Sb, Ga, Ge, As, Se, Sn, Te, Mn, Cu, rare earth elements (Pr, Nd, Dy, Gd, Ho, Er, Nb, Sc, Y, La, Ce, and also other impurities (P, B, Fe, Si, V, Ru, Zr, Hf, Ca, Mg are given. Developed CRMs are used for calibration of optical emission spectrometers, mass-spectrometers with glow discharge and laser sampling and others.

  3. Rare earth permanent-magnet alloys’ high temperature phase transformation in situ and dynamic observation and its application in material design

    Pan, Shuming


    The process of high temperature phase transition of rare earth permanent-magnet alloys is revealed by photographs taken by high voltage TEM. The relationship between the formation of nanocrystal and magnetic properties is discussed in detail, which effects alloys composition and preparation process. The experiment results verified some presumptions, and were valuable for subsequent scientific research and creating new permanent-magnet alloys. The publication is intended for researchers, engineers and managers in the field of material science, metallurgy, and physics. Prof. Shuming Pan is senior engineer of Beijing General Research Institute of Non-ferrous Metal.

  4. Chinalco and China National Administration of Coal Geology Jointly Built Guangxi Rare Earth Industrial Base


    <正>On June 3,Chinalco and China National Administration of Coal Geology signed cooperation agreement for strategic cooperation&cooperation agreement between Chinalco Guangxi Nonferrous Rare Earth Development Company and Xuzhou Jin Shi Pengyuan Rare Earth Material Factory.According to the agreement,both sides would jointly support Chinalco Guangxi Nonferrous Rare Earth Development Company and Xuzhou Jin Shi Pengyuan Rare Earth Material Factory to carry out comprehensive cooperation covering rare

  5. Rare earths: Market disruption, innovation, and global supply chains

    Eggert, Roderick; Wadia, Cyrus; Anderson, Corby; Bauer, Diana; Fields, Fletcher; Meinert, Lawrence D.; Taylor, Patrick


    Rare earths, sometimes called the vitamins of modern materials, captured public attention when their prices increased more than ten-fold in 2010 and 2011. As prices fell between 2011 and 2016, rare earths receded from public view—but less visibly they became a major focus of innovative activity in companies, government laboratories and universities. Geoscientists worked to better understand the resource base and improve our knowledge about mineral deposits that will be mines in the future. Process engineers carried out research that is making primary production and recycling more efficient. Materials scientists and engineers searched for substitutes that will require fewer or no rare earths while providing properties comparable or superior to those of existing materials. As a result, even though global supply chains are not significantly different now than they were before the market disruption, the innovative activity motivated by the disruption likely will have far-reaching, if unpredictable, consequences for supply chains of rare earths in the future.

  6. Solar Energy Cell with Rare Earth Film

    Li Baojun; Yang Tao; Zhou Yao; Zhou Meng; Fu Xiliang; Fu Li


    The characteristic of the solar energy cell with the rare earth film according to theory of molecular structure was introduced.When sunlight shines, the molecules of the rare earth film can absorb energy of the photon and jump to the excited state from the basic state, and play a role in storing solar energy.When sunlight do not shine, the electron of the excited state returns to the basic state, the rare earth film can automatically give out light and shine to surface of the solar cell, which can make solar cell continuously generate electric current.The rare earth film can absorb direct,scattering sunlight, and increase density of solar energy to reach surface of the solar cell, and play focusing function.The rare earth film can bear 350 ~ 500 ℃, which make the solar cell be able to utilize the focusing function system.Because after luminescence of the rare earth film, it can release again the absorbed solar energy through 1 ~ 8 h, and play a role in storing solar energy; The solar cell with the rare-earth film can generate electricity during night and cloudy days, and remarkably increase efficiency of the solar cell.

  7. Geochemistry of Rare Earth Elements in Aktishikan Gold Deposit, Xinjiang

    袁峰; 周涛发; 岳书仓


    The characteristics and the models of rare earth elements in the geolo gical bodies and the hydrothermal water balanced with the adamellite were compre h ensively studied in Aktishikan gold deposit,Nurt area of Altay,Xinjiang.And th e behavior of rare earth elements during metasomatic alteration was discussed by using the isocon method of Grant.The results show that the rare earth elements a re inert during metasomatic alteration,the hydrothermal water has no relation t o the magmatic water,and the gold material sources mainly stem from the wall rock.

  8. Multi-walled carbon nanotube-based ternary rare earth (Eu3+, Tb3+) hybrid materials with organically modified silica-oxygen bridge.

    Li, Qiu-Ping; Yan, Bing


    A series of ternary rare earth (Eu(3+), Tb(3+)) complexes are covalently coated to the 3-aminopropyltriethoxysilane functionalized multi-walled carbon nanotube (MWCNT) by a simple in situ sol-gel method by the bifunctional silylated monomer TTA-Si and TAA-Si (TTA-Si and TAA-Si are 3-(triethoxysilyl)propylisocyanate (TEPIC) modified thenoyltrifluoroacetone (TTA) and trifluoroacetylacetone (TAA), respectively). The resulting materials are characterized by Fourier transform infrared spectra, scanning electronic microscope, transmission electron microscope, thermogravimetric analysis, ultraviolet visible diffused reflection measure, photoluminescence spectra, and X-ray diffraction. The photoluminesce measurements indicated that these hybrids exhibit characteristic red and green luminescence originating from the corresponding ternary rare earth ion (Eu(3+), Tb(3+)). The luminescence quenching effect of MWCNT networks have been successfully restrained by coating a relatively thicker silica-oxygen-based organic-inorganic complex. Furthermore, the fluorescence lifetimes and emission quantum efficiencies of Eu(3+) hybrid materials are also determined. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Rare Earth Doped High Temperature Ceramic Selective Emitters

    Chubb, Donald L.; Pal, AnnaMarie; Patton, Martin O.; Jenkins, Phillip P.


    As a result of their electron structure, rare earth ions in crystals at high temperature emit radiation in several narrow bands rather than in a continuous blackbody manner. This study develops a spectral emittance model for films of rare earth containing materials. Although there are several possible rare earth doped high temperature materials, this study was confined to rare earth aluminum garnets. Good agreement between experimental and theoretical spectral emittances was found for erbium, thulium and erbium-holmium aluminum garnets. Spectral emittances of these films are sensitive to temperature differences across the film. Emitter efficiency is also a sensitive function of temperature. For thulium aluminum garnet the efficiency is 0.38 at 1700 K but only 0.19 at 1262 K.

  10. Thermoelectric transport in rare-earth compounds

    Koehler, Ulrike


    This work focuses on the thermoelectric transport in rare-earth compounds. The measurements of the thermal conductivity, thermopower, and Nernst coefficient are supplemented by investigations of other quantities as magnetic susceptibility and specific heat. Chapter 2 provides an introduction to the relevant physical concepts. Section 1 of that chapter summarizes the characteristic properties of rare-earth systems; section 2 gives an overview on thermoelectric transport processes in magnetic fields. The applied experimental techniques as well as the new experimental setup are described in detail in Chapter 3. The experimental results are presented in Chapter 4-6, of which each concentrates on a different subject. In Chapter 4, various Eu clathrates and the skutterudite-like Ce{sub 3}Rh{sub 4}Sn{sub 13} are presented, which have been investigated as potential thermoelectric materials for applications. Chapter 5 focusses on the study of the energy scales in the heavy-fermion series Lu{sub 1-x}Yb{sub x}Rh{sub 2}Si{sub 2} and Ce{sub x}La{sub 1-x}Ni{sub 2}Ge{sub 2} by means of thermopower investigations. Chapter 6 is dedicated to the thermoelectric transport properties of the correlated semimetal CeNiSn with special emphasis on the Nernst coefficient of this compound. (orig.)

  11. Rare earth elements in nuclear medicine

    Kodina G.E.; Kulakov V.N.; Sheino I.N.


    The review focuses on the key applications of stable and radioactive isotopes of rare earth elements in the technology of nuclear medicine, radionuclide diagnostics and therapy, as well as magnetic resonance imaging and binary radiotherapy technologies.

  12. Rare earth elements in nuclear medicine

    Kodina G.E.


    Full Text Available The review focuses on the key applications of stable and radioactive isotopes of rare earth elements in the technology of nuclear medicine, radionuclide diagnostics and therapy, as well as magnetic resonance imaging and binary radiotherapy technologies.

  13. Rare earth element mines, deposits, and occurrences

    U.S. Geological Survey, Department of the Interior — This dataset contains location, geologic and mineral economic data for world rare earth mines, deposits, and occurrences. The data in this compilation were derived...

  14. Rare Earth: Production, Trade and Demand

    HONG Feng


    @@ Editor's note: The paper was quoted from the papers collection of the "19th International Workshop on Rare Earth Permanent Magnets & Their Applications", held in Beijing on August 30-Spetember 2 of 2006.

  15. China Not the Only Rare Earth Exporter


    Since China announced it was reducing exports of rare earth,there have been continuous voices in the international community demanding China expand exports or seek alternative resources. The United States has also complained to the WTO that China is hoarding the commodity. Subjected to scathing censure,what difficulties are facing China’s rare earth industry? When other countries seek alternative resources,how is the Chinese rare earth market affected? Economy&Nation Weekly,Xinhua News Agency’s finance magazine,recently interviewed Lin Donglu,Secretary General of the Chinese Society of Rare Earths,and Wang Hongqian, General Manager of China Non-Ferrous Metal Industry’s Foreign Engineering and Construction Co.Ltd.Edited excerpts follow

  16. Rare Earth-Activated Silica-Based Nanocomposites

    C. Armellini


    Full Text Available Two different kinds of rare earth-activated glass-based nanocomposite photonic materials, which allow to tailor the spectroscopic properties of rare-earth ions: (i Er3+-activated SiO2-HfO2 waveguide glass ceramic, and (ii core-shell-like structures of Er3+-activated silica spheres obtained by a seed growth method, are presented.



    Remarkable improvements have been made on the crystal growth of rare earth pnictides and chalchogenides by the development of new growth technique and the construction of several new equipments for the crystal growth such as electron beam welding system of tungsten crucible provided with large glove box and vacuum HF furnace. This system has really worked on obtaining excellent quality of single crystals and made easier to explore unknown materials of rare earth compounds. Interesting and att...

  18. 2004 Top 10 Chinese Rare Earth Events


    1. Management to the Investment in Rare Earth IndustryConfirmedIn July 2004, "Decision on the Reform in Investment System" was formally publicized by the State Council of the People's Republic of China. The fifth item in the Decision stipulates that ore exploitation, smelting & separation and rare earth deep-processed projects with total investment over RMB¥100 million should be approved by the investment governing department of the State Council, and that other

  19. 12 Ministries Control Rare Earth Exports


    <正>"It is very natural to reserve rare earth as a strategic resource.Many countries do this,including China."On April 8,Sun Lihui,Vice Director of Metal Section of Chemicals Import & Export Commerce Chamber of China Minmetals Corporation told a reporter that as early as 2006,China has launched a strategic plan for rare earth,"but it was interrupted by the subsequent financial crisis."

  20. Ternary rare earth-lanthanide sulfides

    Takeshita, Takuo; Gschneidner, Jr., Karl A.; Beaudry, Bernard J.


    A new ternary rare earth sulfur compound having the formula: La.sub.3-x M.sub.x S.sub.4 where M is a rare earth element selected from the group europium, samarium and ytterbium and x=0.15 to 0.8. The compound has good high-temperature thermoelectric properties and exhibits long-term structural stability up to C.

  1. Partitioning properties of rare earth ores in China

    CHI Ru'an; LI Zhongjun; PENG Cui; ZHU Guocai; XU Shengming


    The properties of rare earth partitioning in Chinese industrial rare earth ores were analyzed. Rare earth ores can be divided into the single-mineral type ore with bastnaesite, the multi-mineral type ore with bastnaesite and monazite, and the weathering crust type. Both the Bayan Obo rare earth ore and the Zhushan rare earth ore are a kind of mixed ore, consisting of bastnaesite and monazite. Their rare earth partitionings are strongly enriched in light rare earths, where CeO2 is 50% and the light rare earth partitioning is totally over 95%. The Mianning rare earth ore as well as the Weishan rare earth is a kind of rare earth ore only having bastnaesite. Their rare earth partitionings are also strongly enriched in light rare earths,in which CeO2 is 47% and the light rare earth partitioning is totally over 94%. For the weathering crust type rare earth ore,there are the Longnan rare earth ore, the Xunwu rare earth ore, and the middle yttrium and rich europium ore. In the Longnan rare earth ore, which is strongly enriched in heavy rare earths, Y2O3 is 64.83%, and the heavy and light rare earth partitionings are 89.40% and 10.53%, respectively. In the Xunwu rare earth ore, which is strongly enriched in light rare earths, CeO2 is 47.16%, and the light rare earth partitioning is totally 93.25%. Y and Eu are enriched in the middle yttrium and rich europium ore. Its middle rare earth partitioning is totally over 10%, and Eu2O3 and Y2O3 are over 0.5% and 20%,respectively, which are mainly industrial resources of the middle and the heavy rare earths.

  2. Introducing a multi-criteria indicator to better evaluate impacts of rare earth materials production and consumption in life cycle assessment

    N. Adibi; Z. Lafhaj; E.D. Gemechu; G. Sonnemann; J. Payet


    Life cycle assessment (LCA) is based on the basic principles of sustainable development. LCA method demonstrated its efficiency in providing a systematic environmental assessment approach of a product or a process. The effectiveness and efficiency of these methods lies in the fact that they take into account all life cycle stages of a product, from the extraction of raw materials to end of life treatment (recycling, ...) through an assessment covering different impact categories such as climate change, human health, ecosystems and resources. Existing LCA indicators reflect different issues surrounding resource depletion, creating inconsistency and moreover confusion among LCA practitioners. The evaluation of different life cycle impacts assessment (LCIA) methods done by EC JRC showed that available models did not address the same parameters:short-vs long-term, stock vs backup technology, etc. It also showed that if the correlation between the methods was sufficient for some resources, others such as rare earth elements showed a high level of inconsistency between methods. It was therefore necessary to develop a relevant indicator and harmonized assessment of impacts on resources in LCA. Furthermore, a resource strategy indicator based on the three pillars of sustainable development (eco-nomic, environmental and social) would better address wider challenges and making it a more powerful decision making tool. This study aimed to introduce an indicator for evaluating the strategy implications of metal resources for products and to compare different ways of production resulting from extraction of raw materials or recycling, with a special focus on rare earth materials. The indicator would assess the impacts based on a reserve-resource vision [BGS NERC] and the evolution over time and founded over three pa-rameters:technical feasibility, economic viability and political stability (including social and environmental aspects) in representing countries.

  3. Magnetic Rare-Earth Superlattices

    Majkrzak, C.F.; Gibbs, D.; Böni, P.


    The magnetic structures of several single‐crystal, magnetic rare‐earth superlattice systems grown by molecular‐beam epitaxy are reviewed. In particular, the results of recent neutron diffraction investigations of long‐range magnetic order in Gd‐Y, Dy‐Y, Gd‐Dy, and Ho‐Y periodic superlattices...... are presented. In the Gd‐Y system, an antiphase domain structure develops for certain Y layer spacings, whereas modified helical moment configurations are found to occur in the other systems, some of which are commensurate with the chemical superlattice wavelength. References are made to theoretical interaction...

  4. Thermal Expansion and Thermal Conductivity of Rare Earth Silicates

    Zhu, Dongming; Lee, Kang N.; Bansal, Narottam P.


    Rare earth silicates are considered promising candidate materials for environmental barrier coatings applications at elevated temperature for ceramic matrix composites. High temperature thermophysical properties are of great importance for coating system design and development. In this study, the thermal expansion and thermal conductivity of hot-pressed rare earth silicate materials were characterized at temperatures up to 1400 C. The effects of specimen porosity, composition and microstructure on the properties were also investigated. The materials processing and testing issues affecting the measurements will also be discussed.

  5. Anisotropy of rare-earth magnets

    R.Skomski; D.J.Sellmyer


    Rare-earth intermetallics such as Nd2FeI4B and Sm-Co are widely used as high-performance permanent magnets,because they combine high magnetocrystalline anisotropy with reasonable magnetization and Curie temperature.The anisotropy is a combined effect of spin-orbit coupling and electrostatic crystal-field interactions.The main contribution comes from the rare-earth 4f electrons,which are well-screened from the crystalline environment but exhibit a strong spin-orbit coupling.In this limit,the magnetocrystalline anisotropy has a very transparent physical interpretation,the anisotropy energy essentially being equal to the energy of Hund's-rules 4f ion in the crystal field.The corresponding expression for the lowest-order uniaxial anisotropy constant K1 is used to discuss rare-earth substitutions,which have recently attracted renewed interest due to shifts in the rare-earth production and demand.Specific phenomena reviewed in this article are the enhancement of the anisotropy of Sm2Fe17 due to interstitial nitrogen,the use of Sm-Co magnets for high-temperature applications,and the comparison of rare-earth single-ion anisotropy with other single-ion and two-ion mechanisms.

  6. Rare earth elements and permanent magnets (invited)

    Dent, Peter C.


    Rare earth (RE) magnets have become virtually indispensible in a wide variety of industries such as aerospace, automotive, electronics, medical, and military. RE elements are essential ingredients in these high performance magnets based on intermetallic compounds RECo5, RE2TM17 (TM: transition metal), and RE2TM14B. Rare earth magnets are known for their superior magnetic properties—high induction, and coercive force. These properties arise due to the extremely high magnetocrystalline anisotropy made possible by unique 3d-4f interactions between transition metals and rare earths. For more than 40 years, these magnets remain the number one choice in applications that require high magnetic fields in extreme operating conditions—high demagnetization forces and high temperature. EEC produces and specializes in RECo5 and RE2TM17 type sintered magnets. Samarium and gadolinium are key RE ingredients in the powder metallurgical magnet production processes which include melting, crushing, jet milling, pressing, sintering, and heat treating. The magnetic properties and applications of these magnets will be discussed. We will also briefly discuss the past, current, and future of the permanent magnet business. Currently, over 95% of all pure rare earth oxides are sourced from China, which currently controls the market. We will provide insights regarding current and potential new magnet technologies and designer choices, which may mitigate rare earth supply chain issues now and into the future.

  7. Improved Rare-Earth Emitter Hollow Cathode

    Goebel, Dan M.


    An improvement has been made to the design of the hollow cathode geometry that was created for the rare-earth electron emitter described in Compact Rare Earth Emitter Hollow Cathode (NPO-44923), NASA Tech Briefs, Vol. 34, No. 3 (March 2010), p. 52. The original interior assembly was made entirely of graphite in order to be compatible with the LaB6 material, which cannot be touched by metals during operation due to boron diffusion causing embrittlement issues in high-temperature refractory materials. Also, the graphite tube was difficult to machine and was subject to vibration-induced fracturing. This innovation replaces the graphite tube with one made out of refractory metal that is relatively easy to manufacture. The cathode support tube is made of molybdenum or molybdenum-rhenium. This material is easily gun-bored to near the tolerances required, and finish machined with steps at each end that capture the orifice plate and the mounting flange. This provides the manufacturability and robustness needed for flight applications, and eliminates the need for expensive e-beam welding used in prior cathodes. The LaB6 insert is protected from direct contact with the refractory metal tube by thin, graphite sleeves in a cup-arrangement around the ends of the insert. The sleeves, insert, and orifice plate are held in place by a ceramic spacer and tungsten spring inserted inside the tube. To heat the cathode, an insulating tube is slipped around the refractory metal hollow tube, which can be made of high-temperature materials like boron nitride or aluminum nitride. A screw-shaped slot, or series of slots, is machined in the outside of the ceramic tube to constrain a refractory metal wire wound inside the slot that is used as the heater. The screw slot can hold a single heater wire that is then connected to the front of the cathode tube by tack-welding to complete the electrical circuit, or it can be a double slot that takes a bifilar wound heater with both leads coming out

  8. Current Status on Resource and Recycling Technology for Rare Earths

    Takeda, Osamu; Okabe, Toru H.


    The development of recycling technologies for rare earths is essential for resource security and supply stability because high-quality rare earth mines are concentrated in China and the demand for rare earth metals such as neodymium and dysprosium, used as raw materials in permanent magnets (neodymium magnet), is expected to increase rapidly in the near future. It is also important to establish a recycling-based society from the perspective of the conservation of finite and valuable mineral resources and the reduction of the environmental load associated with mining and smelting. In this article, the current status of rare earth resource as well as that of recycling technology for the magnets is reviewed. The importance of establishing an efficient recycling process for rare earths is discussed from the characteristics of supply chain of rare earths, and the technological bases of the recycling processes for the magnet are introduced. Further, some fundamental researches on the development of new recycling processes based on pyrometallurgical process are introduced, and the features of the recycling processes are evaluated.

  9. 2011 Review and outlook of China rare earth market

    Zhang Lihua; Bai Jinlong


    In 2011, the start year of the "Twelfth-Five Year Plan" program, a series of policies were issued targeting on rare earth industry. Price of rare earths fluctuated sharply during 2011 and consumers were concerned about the supply of rare earth. There was a big change in rare earth industry.

  10. 2007 China Rare Earths Import & Export Analysis and Suggestions (continued)

    Yin Jianhua; Zuo Xichao


    @@ 4. Increasing import of rare earth resources products As a big producer and an important export country of rare earth products for years, rare earths import is in an auxiliary position in China. import volume is rather small. However, since the strengthened macro control measures and restriction of mining scale in 2007, domestic rare earth supply was tight in China.

  11. Red mud as secondary source for critical raw materials - purification of rare earth elements by liquid/liquid extraction

    Ujaczki, Éva; Zimmermann, Yannick; Gasser, Christoph; Molnár, Mónika; Feigl, Viktória; Lenz, Markus


    BACKGROUND: Critical raw materials (CRM) are crucial to Europe's economy and essential to maintaining and improving our quality of life due to their usage for production of many devices. Red mud is generated from alumina production where bauxite is digested in hot sodium hydroxide solution during

  12. China Not the Only Rare Earth Exporter


    @@ Since China announced it was reducing exports of rare earth,there have been continuous voices in the international community demanding China expand exports or seek alternative resources.The United States has also complained to the WTO that China is hoarding the commodity.

  13. Non-rare earth magnetic nanoparticles

    Carpenter, Everett E.; Huba, Zachary J.; Carroll, Kyler J.; Farghaly, Ahmed; Khanna, Shiv N.; Qian, Meichun; Bertino, Massimo


    Continuous flow synthetic methods are used to make single phase magnetic metal alloy nanoparticles that do not contain rare earth metals. Soft and hard magnets made from the magnetic nanoparticles are used for a variety of purposes, e.g. in electric motors, communication devices, etc.

  14. Status and development tendency of rare-earth permanent magnet materials%稀土永磁材料的现状与发展趋势



    作为稀土最重要的应用领域之一,稀土永磁材料是支撑现代社会的重要基础功能材料,与人们的生活息息相关。近10余年来,全球烧结钕铁硼磁体毛坯产量年均增长率为20%,我国年均增长率为28%;全球粘结钕铁硼磁体产量年均增长率为7%,我国年均增长率为21%。2012年,我国烧结钕铁硼磁体毛坯产量和粘结钕铁硼磁体产量分别为8.3万吨和4400吨,达到历史最高。近两年,具有高使用温度和优异耐腐蚀性的烧结钐钴磁体和热压/热变形辐射钕铁硼取向环形磁体的产量也有所增长。低碳经济对烧结钕铁硼磁体的综合磁性能指标“(BH)max (MGOe)+Hcj(kOe)”提出了越来越高的要求,目前该指标已超过70;Tb/Dy晶界扩散提高Hcj成为烧结钕铁硼的新热点,已开发出多种扩散技术并用于批量生产。利用氦气气流磨并结合无氧工艺建成的无或低Tb/Dy生产线已经在日本投入运行。粘结磁体方面,各向同性钕铁硼磁粉的国产化进程在加快,(BH)max=15MGOe的高性能磁粉已经面市,成本及耐蚀性更优的快淬Sm-Fe-N磁粉也在大力研发中;HDDR处理的各向异性钕铁硼磁粉已经商品化。高性价比的各向异性磁体成形技术正在开发,挤出成形工艺可制备直径60mm、壁厚1mm的辐射取向薄壁环。为了进一步高效利用稀土,西方国家和中国正在积极开展稀土永磁材料的回收利用。丰富的稀土资源,广阔的应用市场,稀土永磁材料将迎来更加美好的前景。%As one of the most important application for rare earth, the rare-earth permanent magnet material, which closely relates to people’s daily life, is an important fundamental functional material to support modern society. For recent ten years, the average annual growth rate of sintered Nd-Fe-B magnets output is 20% for the whole world and 28% for China. The average annual growth rate of bonded Nd

  15. Influence of processing on structure property correlations in τ-MnAl rare-earth free permanent magnet material

    Singh, Nidhi; Mudgil, Varun; Anand, Kanika; Srivastava, A.K.; Kotnala, R.K.; Dhar, Ajay, E-mail:


    Highlights: • The reported magnetic properties of τ-MnAl show a significant scatter in their data. • We report the synthesis of τ-MnAl employing different processing routes. • The observed magnetic properties were correlated with the synthesis route. • The resulting microstructure has been correlated with the magnetic properties. - Abstract: In order to understand the genesis of the magnetic τ-phase of MnAl alloy, which due to its multiphase nature is generally difficult to synthesize as a single-phase, we have synthesized it employing three different materials processing routes, namely, arc melting, mechanical alloying, and a combination of these two. Structural and microstructural characterizations employing X-ray diffraction and high resolution transmission electron microscopy demonstrate that irrespective of the material processing route employed, the formation of τ-MnAl phase was always accompanied by other non-magnetic phases, e.g., β-MnAl and γ-MnAl. However, the relative fraction of these phases was found to be dependent on the materials processing route and hence on the grain size of the parent phase. The arc melted alloy had the largest grain size and the highest fraction of the τ-MnAl phase, while the alloy prepared by mechanical alloying showed the smallest grain size and the lowest fraction of the magnetic phase. The largest value of Curie temperature, magnetic moment, coercivity and remanence were observed in the sample prepared by a combination of arc melting and mechanical alloying. Our results suggest that in addition to the τ-MnAl phase fraction the magnetic properties could be related to the density of structural defects.

  16. Tuning bad metal and non-Fermi liquid behavior in a Mott material: Rare-earth nickelate thin films.

    Mikheev, Evgeny; Hauser, Adam J; Himmetoglu, Burak; Moreno, Nelson E; Janotti, Anderson; Van de Walle, Chris G; Stemmer, Susanne


    Resistances that exceed the Mott-Ioffe-Regel limit (known as bad metal behavior) and non-Fermi liquid behavior are ubiquitous features of the normal state of many strongly correlated materials. We establish the conditions that lead to bad metal and non-Fermi liquid phases in NdNiO3, which exhibits a prototype bandwidth-controlled metal-insulator transition. We show that resistance saturation is determined by the magnitude of Ni eg orbital splitting, which can be tuned by strain in epitaxial films, causing the appearance of bad metal behavior under certain conditions. The results shed light on the nature of a crossover to a non-Fermi liquid metal phase and provide a predictive criterion for Anderson localization. They elucidate a seemingly complex phase behavior as a function of film strain and confinement and provide guidelines for orbital engineering and novel devices.

  17. Rare Earth Elements Geochemistry of Laowan Gold Deposit in Henan Province: Trace to Source of Ore-Forming Materials


    The compositions of REE in quartz and pyrite from the main stage of the Laowan gold deposit in Henan Province and that in quartz from Laowan granite were determined by inductively coupled plasma-mass-spectrometry (ICP-MS) to trace the source of ore-forming materials. Meanwhile, the REE compositions of the deposit ore, granite and metamorphic wall rock were also considered for comparative studies in detail. The range of ∑REE of quartz and pyrite from the deposit ores is 4.18×10-6~30.91×10-6, the average of ∑REE is 13.39×10-6, and the average of ∑REE of quartz in the Laowan granite is 6.68×10-6. There is no distinct difference of REE parameters between the deposit ore quartz and granite quartz. The quartz in gold deposit has the same REE particular parameters as quartzes from Laowan granite, such as δEu, δCe, (La/Yb)N and (La/Sm)N, partition degree of LREE to HREE, especially, the chondrite-normalized REE patterns, but no similarity to those from metamorphic wall rock, which shows that ore-forming hydrothermal fluid is mainly the fluid coming from the Laowan granite magma, rather than metamorphic fluid. Meanwhile, comparison studies on REE features between minerals from the deposit ores and related geological bodies in the deposit show that REE characteristics of minerals can serve as an indicator of ore-forming fluid properties and sources, while the REE characteristics of the bulk samples (such as deposit ores, granites and wall rocks) can not trace the source of the ore-forming materials exactly.

  18. Ultrasonic attenuation in rare-earth monoarsenides



    The present paper deals with the theoretical calculation of mechanical and thermophysical properties of rare-earth monoarsenides, XAs (X: Np, Pu, Th and U) using elastic constants as the input parameters. These second- and third-order elastic constants (SOECs and TOECs) are determinedin the temperature range 100–500K using Coulomb and Born–Mayer potential upto second nearest neighbours. In order to provide the link between mechanical and dynamical behaviour of crystals, parameters such as Young’s modulus, bulk modulus, Poisson’s ratio etc. are also calculated.In addition, the Cauchy relationship is obeyed by the chosen monoarsenides and are fairly anisotropic, which results in the measurement of longitudinal and shear wave velocities along $\\langle100 \\rangle$, $\\langle110\\rangle$ and $\\langle 111\\rangle$ directions. The toughness/fracture $(G/BT)$ ratio is greater than 0.60, which implies that XAs compounds are brittle at room temperature. Further, the Debye temperature is computed using Debye average velocity as the input parameter. It helps in the characterization of lattice vibrations of a solid. In this work, ultrasonic attenuation due to phonon–phonon interaction$\\alpha/f^2_{\\rm p−p}$ and thermoelastic loss $\\alpha/f ^{2}$th are computed for XAs from 100 to 500K using Mason’s theory. It further helps in evaluating the microstructural properties of the chosen materials. The obtained results indicate that XAs is mechanically stable and are compared with data availablein the literature.

  19. Effect of γ-radiation on thermoluminescence in rare earths doped NaMgSO4Cl material

    Choubey, S. R.; Gedam, S. C.; Dhoble, S. J.


    The thermoluminescence (TL) characteristics, effect of γ-radiation on NaMgSO4Cl: X (X = Tb; Ce, Tb; Dy; Dy, Eu) and trapping parameters in TL material prepared by wet chemical synthesis (WCS) method are studied. The intensity of these phosphors is compared with TLD CaSO4: Dy phosphor. The phosphor has a simple TL glow curve structure. The phosphors NaMgSO4Cl: Tb (between the range of 257-284°C); NaMgSO4Cl: Dy (173°C) and NaMgSO4Cl: Dy, Eu (156°C) have a single prominent peak, whereas NaMgSO4Cl: Ce, Tb has two peaks located at 154°C and 233°C indicating single and double trapping sites, respectively. It is found that intensity tends to be increase with increased concentrations of the activators. The TL glow curves of the phosphors have been recorded and irradiated at a rate of 0.99 kGyh-1 for 5 Gy γ-rays dose. The paper also discusses the kinetic parameters evaluated by Chen's half width method such as activation energy E (eV) and frequency factor S (s-1).

  20. Effect of Rare Earths on Composition and Activities of Rare Earth Elements Binding Glycoprotein in Tea

    汪东风; 李俊; 赵贵文; 王常红; 魏正贵; 尹明


    The effects of spraying rare earths(RE) on composition and activities of tea polysaccharide were measured by inductively coupled plasma mass spectrometry (ICP-MS), gas chromatography(GC), amino acid analyzer and animal models. The results show that there are rare earth elements binding glycoprotein in tea (REE-TGP). The effects of RE on composition and content of saccharides in REE-TGP are not obvious. The contents of Hypro and Ser in REE-TGP are evidently enhanced in comparison with that in control (not treated with rare earth), but the content of Glu is smaller than that from control. The content of La in REE-TGP from the tea garden sprayed rare earth is 193% higher than that in control. REE-TGP declines content of blood sugar in mice and enhances immunization of rat, which are very evident when the animals are treated by REE-TGP from the tea garden sprayed RE.

  1. Research of Optical Performance On Rare-Earth Optical Fiber

    Li Baojun; Zhou Meng; Yang Tao; Zhou Yao; Fu Li; Li Tiansi; YangShilong


    The rare-earth optical fiber is made of organic material and inorganic rare earth material.It can be used to absorb and transfer solar energy.When sunlight irradiates, it may absorb and transfer solar energy automatically; while at night or without sunlight it may give out light and play role of decoration.By utilizing high transmissivity of organic material and heat-resisting performance of inorganic material, we know the reorganization of material performance under the melting condition, and make empty core bear the high temperature of 150 ~200 ℃.When the light spreads in light guide, some light energy travels along the direction of light guide, and is introduced in the room directly.Another part of light energy is absorbed and stored by light guide, and can release light again after 8 ~ 12 h.

  2. Alleviation Effects of Rare Earth on Cd Stress to Rape

    马建军; 张淑侠; 朱京涛; 吴贺平


    Using rapes as test materials, the fastness expression and alleviation effect of rapes were studied under Cd stress condition, as the rapeseeds were dipped in the single element(La, Ce, Nd, Pr)and mixed rare earth(RE). The results indicate that, under Cd stress, the dry and fresh weight are increased by both the single element and mixed rare earth treatment, and the fastness of rape is improved.The single element of rare earth decreases the Cd content in rape roots and transmits Cd to the edible parts above the ground in which the alleviation effect of Ce is most significant.La treatment takes the second place, so that the poisonous effect of heavy metal Cd is eased.The mixed rare earth doesn't alleviate the assimilation of Cd in rape roots, but accelerates the transfer of Cd to the parts above the ground. The research puts forward that the alleviation of rare earth on Cd stress has connection with the decrease of Ca content.

  3. Study on Microstructure of Alumina Based Rare Earth Ceramic Composite


    Analysis techniques such as SEM, TEM and EDAX were used to investigate the microstructure of rare earth reinforced Al2O3/(W, Ti)C ceramic composite. Chemical and physical compatibility of the composite was analyzed and interfacial microstructure was studied in detail. It is found that both Al2O3 and (W, Ti)C phases are interlaced with each other to form the skeleton structure in the composite. A small amount of pores and glass phases are observed inside the material which will inevitably influence the physical and mechanical property of the composite. Thermal residual stresses resulted from thermal expansion mismatch can then lead to the emergence of dislocations and microcracks. Interfaces and boundaries of different types are found to exist inside the Al2O3/(W, Ti)C rare earth ceramic composite, which is concerned with the addition of rare earth element and the extent of solid solution of ceramic phases.

  4. Theory of Rare-Earth Alloys

    Lindgård, Per-Anker


    A mean-field random alloy theory combined with a simple calculation of the exchange interaction J(c,Q) is shown to quantitatively account for the phase diagrams for alloys of rare-earth metals with Y, Lu, Sc, and other rare-earth metals. A concentration-dependent J(c,Q) explains the empirical 2...... to account for all alloys except the Sc based. The exceptional behavior of the Sc alloys is due to a low density of states for Sc. A brief discussion is given of the effect on the mean-field results of changes in volume or c/a ratio and of critical fluctuations. Since the physical mechanisms of these ideal...

  5. Rare Earth Additions in Continuously Cast Steel

    Wilson, William G.; Heaslip, L. J.; Sommerville, I. D.


    Rare earth (lanthanide metals) addiiions to continuously cast steel are particularly advantageous because of their ability to refine as-cast structures, reduce segregation and increase hot ductility at temperatures just below that of solidification. The complete shape control of sulfides in steels containing Rare Earth Metals (REM), whether continuously cast or ingot cast, is primarily responsible for improvements in ductility related mechanical properties, weldability, fatigue resistance and resistance to hydrogen damage. Complete sulfide shape control can be obtained with REM additions at sulfur levels as high as.020%. The greatest improvements, however, are obtained with REM additions to low sulfur steels. However, to achieve full operational advantages afforded by REM, nozzle blockage problems must be circumvented. Water model studies indicate a possible solution.

  6. VUV spectroscopy of nominally pure and rare-earth ions doped LiCaAIF6 single crystals as promising materials for 157 nm photolithography

    Cefalas, Alkiviadis C.; Sarantopoulou, Evangelia; Kollia, Z.; Abdulsabirov, R. Y.; Korableva, S. L.; Naumov, A. K.; Semashko, V. V.; Kobe, S.; McGuiness, P. J.


    Recently it was found that birefringence is induced in CaF2 crystals when they are illuminated with laser light at 157 nm. Taking into consideration that CaF2 is the only optical material used in 157 nm photolithography today, the possibility to use new wide band gap fluoride crystals as optical elements for 157 nm photolithography, even those of non-cubic symmetry, should be considered. Additionally fluoride dielectric crystals with wide band gaps doped with trivalent rare-earth (RE) ions can be used as passive or active optical elements int eh VUV. For doped crystals, applications depend on the structure of the energy level pattern of the 4fn-15d electronic configuration and RE ion concentration. In this work we are exploiting the use of wide band gap fluoride dielectric crystals doped with RE ions. The laser induced fluorescence spectrum at 157 nm, and the absorption spectra of the LiCaAlF6 crystals, pure and doped with RE ions, were investigated in the VUV region of the spectrum. A new m4tehod for monitoring RE concentration in wide band gap fluoride crystals, that is based on vibrating sample magnetometer measurement is presented as well.

  7. Supramolecular Assembly of Molecular Rare-Earth-3,5-Dichlorobenzoic Acid-2,2':6',2″-Terpyridine Materials: Structural Systematics, Luminescence Properties, and Magnetic Behavior.

    Carter, Korey P; Thomas, Kara E; Pope, Simon J A; Holmberg, Rebecca J; Butcher, Ray J; Murugesu, Muralee; Cahill, Christopher L


    The syntheses and crystal structures of 16 new rare-earth (RE = La(3+)-Y(3+))-3,5-dichlorobenzoic acid-terpyridine molecular materials characterized via single-crystal and powder X-ray diffraction are reported. These 16 complexes consist of four unique structure types ranging from molecular dimers (La(3+) and Ce(3+)) to tetramers (Pr(3+)-Y(3+)) as one moves across the RE(3+) series. This structural evolution is accompanied by subsequent changes in modes of supramolecular assembly (halogen bonding, halogen-π, halogen-halogen, and π-π interactions). Solid-state visible and near-infrared lifetime measurements were performed on complexes 6 (Sm(3+)), 7 (Eu(3+)), 9 (Tb(3+)), 10 (Dy(3+)), 11 (Ho(3+)), 12 (Er(3+)), and 14 (Yb(3+)), and characteristic emission was observed for all complexes except 11. Lifetime data for 11, 12, and 14 suggest sensitization by the terpy antenna does occur in near-infrared systems, although not as efficiently as in the visible region. Additionally, direct current magnetic susceptibility measurements were taken for complexes 10 (Dy(3+)) and 12 (Er(3+)) and showed dominant ferromagnetic behavior.

  8. Removal of ammonia from aqueous solutions by catalytic oxidation with copper-based rare earth composite metal materials: catalytic performance, characterization, and cytotoxicity evaluation

    Chang-Mao Hung


    Ammonia (NH3) has an important use in the chemical industry and is widely found in industrial wastewater.For this investigation of copper-based rare earth composite metal materials,aqueous solutions containing 400 mg/L of ammonia were oxidized in a batch-bed reactor with a catalyst prepared by the co-precipitation of copper nitrate,lanthanum nitrate and cerium nitrate.Barely any of the dissolved ammonia was removed by wet oxidation without a catalyst,but about 88% of the ammonia was reduced during wet oxidation over the catalysts at 423 K with an oxygen partial pressure of 4.0 MPa.The catalytic redox behavior was determined by cyclic voltammetry (CV).Furthermore,the catalysts were characterized using thermogravimetric analyzer (TGA) and scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX),which showed that the catalytic behavior was related to the metal oxide properties of the catalyst.In addition,the copper-lanthanum-cerium composite-induced cytotoxicity in the human lung MRC-5 cell line was tested,and the percentage cell survival was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetra-zolium (MTS) analysis in vitro.No apparent cytotoxicity was observed when the human lung cells were exposed to the copper-lanthanum-cerium composite.

  9. Model for the magnetic phases observed at low temperatures in reduced YBa2Cu3O6+x materials with Al substitution for Cu or rare earth ions for Ba

    Andersen, N.H.; Uimin, G.


    From a classical statistical model it is shown that the low temperature antiferromagnetic AFII phase, observed in reduced YBa2Cu3O6+x type materials with Al in the CuOx basal plane or rare earth on the Ba site, results from an effective ferromagnetic coupling between adjacent CuO2 double layers...

  10. Rare earth optogalvanic spectroscopy: preliminary results

    Destro, Marcelo G.; Neri, Jose W.; Rodrigues, Nicolau A.S.; Silveira, Carlos A.B.; Riva, Rudimar [Instituto de Estudos Avancados (IEAv/EFO), Sao Jose dos Campos, SP (Brazil). Div. de Fotonica]. E-mail:; Victor, Alessandro R. [Instituto Tecnologico de Aeronautica (ITA), Sao Jose dos Campos, SP (Brazil)


    The IEAv has special interest in the studies of rare earth isotope applications in laser medium and integrated optics as well as aerospace research. We are starting to work with Ytterbium, Erbium, Dysprosium and Neodymium laser selective photoionization research. This paper describes the preliminary results of emission and optogalvanic spectroscopy obtained from a Neodymium hollow cathode lamps. Furthermore these results were used to setup our laser systems to work to leads a Nd isotopes selective laser photoionization. (author)

  11. Systematic variation of rare earths in monazite

    Murata, K.J.; Rose, H.J.; Carron, M.K.


    Ten monazites from widely scattered localities have been analyzed for La, Ce, Pr, Nd, Sm, Gd, Y and Th by means of a combined chemical and emission spectrographic method. The analytical results, calculated to atomic percent of total rare earths (thorium excluded), show a considerable variation in the proportions of every element except praseodymium, which is relatively constant. The general variation trends of the elements may be calculated by assuming that the monazites represent different stages in a fractional precipitation process, and by assuming that there is a gradational increase in the precipitability of rare earth elements with decreasing ionic radius. Fractional precipitation brings about an increase in lanthanum and cerium, little change in praseodymium, and a decrease in neodymium, samarium, gadolinium, and yttrium. Deviations from the calculated lines of variation consist of a simultaneous, abnormal increase or decrease in the proportions of cerium, praseodymium, and neodymium with antipathetic decrease or increase in the proportions of the other elements. These deviations are ascribed to abnormally high or low temperatures that affect the precipitability of the central trio of elements (Ce, Pr, Nd) relatively more than that of the other elements. The following semiquantitative rules have been found useful in describing the composition of rare earths from monazite: 1. 1. The sum of lanthanum and neodymium is very nearly a constant at 42 ?? 2 atomic percent. 2. 2. Praseodymium is very nearly constant at 5 ?? 1 atomic percent. 3. 3. The sum of Ce, Sm, Gd, and Y is very nearly a constant at 53 ?? 3 atomic percent. No correlation could be established between the content of Th and that of any of the rare earth elements. ?? 1953.

  12. Phase Behavior of Rare Earth Manganites

    Naoki Kamegashira; Hiromi Nakano; Gang Chen; Jian Meng


    Among complex oxides containing rare earth and manganese BaLn2Mn2O7 (Ln=rare earth) with the layered perovskite type and Ln2(Mn, M)O7 with pyrochlore-related structure were studied since these compounds show many kinds of phases and unique phase transitions. In BaLn2Mn2O7 there appear many phases, depending on the synthetic conditions for each rare earth. The tetragonal phase of so-called Ruddlesden-Popper type is the fundamental structure and many kinds of deformed modification of this structure are obtained. For BaEu2Mn2O7 at least five phases have been identified from the results of X-ray diffraction analysis with the space group P42/mnm, Fmmm, Immm and A2/m in addition to the fundamental tetragonal I4/mmm phase. In the pyrochlore-related type compounds, Ln2Mn2-xMxO7 (M=Ta, Nb, W etc), there also appear several phases with different crystal structures. With regard to every rare earth, Ln2MnTaO7 phase is stable only for excess Ta and can be obtained under high oxygen partial pressure process. This group has trigonal structure with zirkelite type (P3121 space group). On the other hand Ln2Mn2/3Nb4/3O7 phase has monoclinic (C2/c space group) and zirconolite type structure. All of these structural models have the fundamental structure based on HTB (hexagonal tungsten bronze) layers formed by the arrangement of oxygen octahedra.

  13. Molecular catalysis of rare-earth elements

    Roesky, Peter W. (ed.) [Karlsruhe Institute of Technology (KIT) (Germany). Inst. of Inorganic Chemistry


    This volume reviews the recent developments in the use of molecular rare-earth metal compounds in catalysis. Most of the applications deal with homogenous catalysis but in some cases, heterogeneous systems are also mentioned. The rare-earth elements, which are the lanthanides and their close relatives - scandium and yttrium - have not been in the focus of molecular chemistry for a long time and therefore have also not been considered as homogenous catalysts. Although the first organometallic compounds of the lanthanides, which are tris(cyclopentadienyl) lanthanide complexes, were already prepared in the 1950s, it was only in the late 1970s and early 1980s when a number of research groups began to focus on this class of compounds. One reason for the development was the availability of single crystal X-ray diffraction techniques, which made it possible to characterize these compounds.Moreover, new laboratory techniques to handle highly air and moisture sensitive compounds were developed at the same time. Concomitant with the accessibility of this new class of compounds, the application in homogenous catalysis was investigated. One of the first applications in this field was the use of lanthanide metallocenes for the catalytic polymerization of ethylene in the early 1980s. In the last two or three decades, a huge number of inorganic and organometallic compounds of the rare-earth elements were synthesized and some of them were also used as catalysts. Although early work in homogenous catalysis basically focused only on the hydrogenation and polymerization of olefins, the scope for catalytic application today is much broader. Thus, a large number of catalytic {sigma}-bond metathesis reactions, e.g. hydroamination, have been reported in the recent years. This book contains four chapters in which part of the recent development of the use of molecular rare-earth metal compounds in catalysis is covered. To keep the book within the given page limit, not all aspects could be

  14. Magnetic Partitioning Nanofluid for Rare Earth Extraction from Geothermal Fluids

    McGrail, Bernard P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Thallapally, Praveen K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Liu, Jian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nune, Satish K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    Rare earth metals are critical materials in a wide variety of applications in generating and storing renewable energy and in designing more energy efficient devices. Extracting rare earth metals from geothermal brines is a very challenging problem due to the low concentrations of these elements and engineering challenges with traditional chemical separations methods involving packed sorbent beds or membranes that would impede large volumetric flow rates of geothermal fluids transitioning through the plant. We are demonstrating a simple and highly cost-effective nanofluid-based method for extracting rare earth metals from geothermal brines. Core-shell composite nanoparticles are produced that contain a magnetic iron oxide core surrounded by a shell made of silica or metal-organic framework (MOF) sorbent functionalized with chelating ligands selective for the rare earth elements. By introducing the nanoparticles at low concentration (≈0.05 wt%) into the geothermal brine after it passes through the plant heat exchanger, the brine is exposed to a very high concentration of chelating sites on the nanoparticles without need to pass through a large and costly traditional packed bed or membrane system where pressure drop and parasitic pumping power losses are significant issues. Instead, after a short residence time flowing with the brine, the particles are effectively separated out with an electromagnet and standard extraction methods are then applied to strip the rare earth metals from the nanoparticles, which are then recycled back to the geothermal plant. Recovery efficiency for the rare earths at ppm level has now been measured for both silica and MOF sorbents functionalized with a variety of chelating ligands. A detailed preliminary techno-economic performance analysis of extraction systems using both sorbents showed potential to generate a promising internal rate of return (IRR) up to 20%.

  15. Rare Power China begins reinvigorate the rare earth industry after decades of underselling the valua metals

    HU YUE


    On May 19,the State Council released Guidelines to Promote Sustainable and Sound Development of the Rare Earth Industry,delivering a strong boost to the fragmented industry.Rare earth elements,a collection of 17 elements,are among the most soughtafter materials for modern manufacturing.Their unique magnetic and phosphorescent properties make them vital ingredients in sophisticated hi-tech devices like batteries,magnets,wind turbines,cellphones,electric cars and flat-screen televisions.However,mining and smelting the elements are difficult and costly.

  16. Synthesis, Characterization and Antibacterial Activity of Hybrid Materials of Rare Earth and Chitosan%稀土壳聚糖杂化材料的制备、表征及抑菌活性研究

    欧玉静; 吴龑平; 李红霞; 王坤杰; 张德懿


    在室温条件下,以天然高分子材料壳聚糖和稀土纳米氧化物为原料,用表面接枝法制备了两种RE2O3-TDI-壳聚糖(TDI=甲苯-2,4-二异氰酸酯,RE=镧,钕)杂化复合物,借助红外(IR)、热重(DSC-TG)、扫描电镜(SEM)等测试技术对所制备的壳聚糖杂化材料的物化性能进行了表征,并采用培养基扩散法和营养肉汤稀释法等抑菌实验方法对其进行了抑菌活性实验,结果表明该稀土纳米壳聚糖杂化材料具有很好的热稳定性及抑菌性能.%The two hybrid materials of RE2O3-TDI-CTS ( TDI= Toluene-2, 4-diisocya-nate, RE = La, Nd) were prepared by surface grafting. The TDI was grafted on nano-rare earth oxides and chitosan with natural polymer material chitosan and nano-rare earth oxides at room temperature, to obtain rare earth chitosan hybrid. The hybrid materials were characterized by IR, TG and SEM, which confirmed that the chi- tosan was grafted on the surface of rare-earth nano-ox-ide of TDI. Its biological antibacterial activity experiments were studied based on the medium diffusion and nutrient broth dilution. The experiments' results indicated that the rare earth nano-oxides chitosan hybrid materials have good thermal stability and antibacterial properties.

  17. An Integrated Rare Earth Elements Supply Chain Strategy


    FL: CRC Press, 2005) 1, 61, 59. 7 Gupta and Krishnamurthy, Extractive Metallurgy of Rare Earths, 21, 22, 32; Cindy A. Hurst, ―China‘s Ace in the...Supply Chain, Briefing for Congressional Committees, 27. 17 Ibid, 24. 18 Gupta and Krishnamurthy, Extractive Metallurgy of Rare Earths, 57. 19 Ibid...Oct 12, 2010): 3. 38 Gupta and Krishnamurthy, Extractive Metallurgy of Rare Earths, 94. 39 U.S. Government Accountability Office, Rare Earth

  18. Reduction property of rare earth oxide doped molybdenum oxide


    Rare earth oxide doped molybdenum powders were prepared by the reduction of rare earth nitrites doped MoO3. The effect of rare earth oxide on the reduction behavior of molybdenum oxide had been studied by means of Temperature Programmed Reduction (TPR), thermal analysis, X-ray diffraction. Doping rare earth oxide in the powder could lower the reduction temperature of molybdenum oxide and decrease the particle size of molybdenum. The mechanism for the effects had been discussed in this paper.

  19. 2007 China Rare Earths Import & Export Analysis and Suggestions


    @@ Ⅰ. Chinese rare earth import & export status in 2007 China further strengthened regulations on import & export of rare earth products in 2007. Firstly, NDRC changed the guidance for rare earth production from guiding plan into mandatory plan at the year beginning.

  20. CISRI Competes for Light Rare Earth in North China


    <正>In the light rare earth market of north China,REHT,the largest rare earth enterprise in the world,has to face a bitter rival in competition.As 3 SOEs(CHINALCO,Minmetals and CNMC)are vying for the medium and heavy rare earth market of South China,a smaller SOE,i.e.,China Iron & Steel Research

  1. China is Planning to Raise rare Earth Resource Tax Again


    <正>In the face of the current situation of the lost WTO dispute on rare earth,and cancellation of export tariff for partial rare earth products,efforts of regulation and integration on rare earth by the state government will again be tightened.Reporters of the Economic Information Daily recently learned from authoritative sources that relevant ministries are

  2. Rare earth elements behavior in Peruibe black mud

    Torrecilha, Jefferson K.; Carvalho, Leandro P.; Gouvea, Paulo F.M.; Silva, Paulo S.C. da, E-mail: [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)


    Rare earth elements in sediments have been used as powerful tools for environmental studies because of their behavior during geochemical processes and are also widely accepted as reliable provenance tracers because they are largely water-immobile and thus behave conservatively during sedimentary processes. The Peruibe Black Mud (PBM) is a sedimentary deposit originated from the interactions of marine sediments and organic matter in an estuarine environment that originates a peloid currently used for medicinal purposes. The objective of this study was to examine rare earth elements pattern distribution in the Peruibe black mud sedimentary deposit as a proxy for its geochemical development. Elemental ratios such as LaN/YbN, Th/U and La/Th were determined and a normalization of the mean rare earth elements concentrations in the samples related to NASC indicates that the light (La to Eu) rare earth elements present values close to the unity while the heavy (Tb to Lu) rare earth elements are depleted related to NASC. It can be observed that the light rare earth elements present enrichment values slightly enriched over the unity while the heavy rare earth elements present values generally below the unity reflecting the enrichment of the light rare earth elements over the heavy rare earth. Rare earth elements concentrations determined in Peruibe black mud samples showed a distribution similar to that found in the NASC for the light rare earth elements and depleted for the heavy rare earth elements. (author)

  3. Byproduct metals and rare-earth elements used in the production of light-emitting diodes—Overview of principal sources of supply and material requirements for selected markets

    Wilburn, David R.


    The use of light-emitting diodes (LEDs) is expanding because of environmental issues and the efficiency and cost savings achieved compared with use of traditional incandescent lighting. The longer life and reduced power consumption of some LEDs have led to annual energy savings, reduced maintenance costs, and lower emissions of carbon dioxide, sulfur dioxide, and nitrogen oxides from powerplants because of the resulting decrease in energy consumption required for lighting applications when LEDs are used to replace less-energy-efficient sources. Metals such as arsenic, gallium, indium, and the rare-earth elements (REEs) cerium, europium, gadolinium, lanthanum, terbium, and yttrium are important mineral materials used in LED semiconductor technology. Most of the world's supply of these materials is produced as byproducts from the production of aluminum, copper, lead, and zinc. Most of the rare earths required for LED production in 2011 came from China, and most LED production facilities were located in Asia. The LED manufacturing process is complex and is undergoing much change with the growth of the industry and the changes in demand patterns of associated commodities. In many respects, the continued growth of the LED industry, particularly in the general lighting sector, is tied to its ability to increase LED efficiency and color uniformity while decreasing the costs of producing, purchasing, and operating LEDs. Research is supported by governments of China, the European Union, Japan, the Republic of Korea, and the United States. Because of the volume of ongoing research in this sector, it is likely that the material requirements of future LEDs may be quite different than LEDs currently (2011) in use as industry attempts to cut costs by reducing material requirements of expensive heavy rare-earth phosphors and increasing the sizes of wafers for economies of scale. Improved LED performance will allow customers to reduce the number of LEDs in automotive, electronic

  4. Enhanced separation of rare earth elements

    Lyon, K. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Greenhalgh, M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Herbst, R. S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Garn, T. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Welty, A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Soderstrom, M. D. [Cytec Solvay Group, Tempe, AZ (United States); Jakovljevic, B. [Cytec Solvay Group, Niagara Falls, ON (Canada)


    Industrial rare earth separation processes utilize PC88A, a phosphonic acid ligand, for solvent extraction separations. The separation factors of the individual rare earths, the equipment requirements, and chemical usage for these flowsheets are well characterized. Alternative ligands such as Cyanex® 572 and the associated flowsheets are being investigated at the pilot scale level to determine if significant improvements to the current separation processes can be realized. These improvements are identified as higher separation factors, reduced stage requirements, or reduced chemical consumption. Any of these improvements can significantly affect the costs associated with these challenging separation proccesses. A mid/heavy rare earth element (REE) separations flowsheet was developed and tested for each ligand in a 30 stage mixer-settler circuit to compare the separation performance of PC88A and Cyanex® 572. The ligand-metal complex strength of Cyanex® 572 provides efficient extraction of REE while significantly reducing the strip acid requirements. Reductions in chemical consumption have a significant impact on process economics for REE separations. Partitioning results summarized Table 1 indicate that Cyanex® 572 offers the same separation performance as PC88A while reducing acid consumption by 30% in the strip section for the mid/heavy REE separation. Flowsheet Effluent Compositions PC88A Cyanex® 572 Raffinate Mid REE Heavy REE 99.40% 0.60% 99.40% 0.60% Rich Mid REE Heavy REE 2.20% 97.80% 0.80% 99.20% Liquor Strip Acid Required 3.4 M 2.3 M Table 1 – Flowsheet results comparing separation performance of PC88A and Cyanex® 572 for a mid/heavy REE separation.

  5. Uncovering the end uses of the rare earth elements

    Du, Xiaoyue, E-mail: [Swiss Federal Laboratories for Materials Science and Technology (EMPA), Lerchenfeldstrasse 5, 9014 St. Gallen (Switzerland); Yale University, 195 Prospect Street, New Haven CT 06511 (United States); Graedel, T.E. [Yale University, 195 Prospect Street, New Haven CT 06511 (United States)


    The rare earth elements (REE) are a group of fifteen elements with unique properties that make them indispensable for a wide variety of emerging and conventional established technologies. However, quantitative knowledge of REE remains sparse, despite the current heightened interest in future availability of the resources. Mining is heavily concentrated in China, whose monopoly position and potential restriction of exports render primary supply vulnerable to short term disruption. We have drawn upon the published literature and unpublished materials in different languages to derive the first quantitative annual domestic production by end use of individual rare earth elements from 1995 to 2007. The information is illustrated in Sankey diagrams for the years 1995 and 2007. Other years are available in the supporting information. Comparing 1995 and 2007, the production of the rare earth elements in China, Japan, and the US changed dramatically in quantities and structure. The information can provide a solid foundation for industries, academic institutions and governments to make decisions and develop strategies. - Highlights: • We have derived the first quantitative end use information of the rare earths (REE). • The results are for individual REE from 1995 to 2007. • The end uses of REE in China, Japan, and the US changed dramatically in quantities and structure. • This information can provide solid foundation for decision and strategy making.

  6. Note: Portable rare-earth element analyzer using pyroelectric crystal

    Imashuku, Susumu, E-mail:; Fuyuno, Naoto; Hanasaki, Kohei; Kawai, Jun [Department of Materials Science and Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan)


    We report a portable rare-earth element analyzer with a palm-top size chamber including the electron source of a pyroelectric crystal and the sample stage utilizing cathodoluminescence (CL) phenomenon. The portable rare-earth element analyzer utilizing CL phenomenon is the smallest reported so far. The portable rare-earth element analyzer detected the rare-earth elements Dy, Tb, Er, and Sm of ppm order in zircon, which were not detected by scanning electron microscopy-energy dispersive X-ray spectroscopy analysis. We also performed an elemental mapping of rare-earth elements by capturing a CL image using CCD camera.

  7. Study on rare earth/alkaline earth oxide-doped CeO2 solid electrolyte

    YAN Kai; ZHEN Qiang; Song Xiwen


    Five types of rare earth/alkaline earth oxide-doped CeO2 superfine-powders were synthesized by a low-temperature combustion technique. The relevant solid electrolyte materials were also sintered by pressureless sintering at different temperatures. The results of X-ray diffraction and transmission electron microscopy showed that the grain size of the powders was approximately 20-30 nm, and rare earth/alkaline earth oxides were completely dissolved into ceria-based solid solution with fluorite structure. The electrical conductivities of the Sm2O3-CeO2 system were measured by the ac impedance technique in air at temperatures ranging from 513-900℃. The results indicated that the ionic conductivities of Sm0.20Ce0.8O1.875 solid electrolyte increase with increasing sintering temperature, and the relationship between the conductivities and measuring temperature obeys the Arrhenius equation. Then the Sm2O3-CeO2 material was further doped with other rare earth/alkaline earth oxide, and the conductivities improve with the effective index.

  8. Compact Rare Earth Emitter Hollow Cathode

    Watkins, Ronald; Goebel, Dan; Hofer, Richard


    A compact, high-current, hollow cathode utilizing a lanthanum hexaboride (LaB6) thermionic electron emitter has been developed for use with high-power Hall thrusters and ion thrusters. LaB6 cathodes are being investigated due to their long life, high current capabilities, and less stringent xenon purity and handling requirements compared to conventional barium oxide (BaO) dispenser cathodes. The new cathode features a much smaller diameter than previously developed versions that permit it to be mounted on axis of a Hall thruster ( internally mounted ), as opposed to the conventional side-mount position external to the outer magnetic circuit ("externally mounted"). The cathode has also been reconfigured to be capable of surviving vibrational loads during launch and is designed to solve the significant heater and materials compatibility problems associated with the use of this emitter material. This has been accomplished in a compact design with the capability of high-emission current (10 to 60 A). The compact, high-current design has a keeper diameter that allows the cathode to be mounted on the centerline of a 6- kW Hall thruster, inside the iron core of the inner electromagnetic coil. Although designed for electric propulsion thrusters in spacecraft station- keeping, orbit transfer, and interplanetary applications, the LaB6 cathodes are applicable to the plasma processing industry in applications such as optical coatings and semiconductor processing where reactive gases are used. Where current electrical propulsion thrusters with BaO emitters have limited life and need extremely clean propellant feed systems at a significant cost, these LaB6 cathodes can run on the crudest-grade xenon propellant available without impact. Moreover, in a laboratory environment, LaB6 cathodes reduce testing costs because they do not require extended conditioning periods under hard vacuum. Alternative rare earth emitters, such as cerium hexaboride (CeB6) can be used in this

  9. Gyroscopic g factor of rare earth metals

    Ogata, Y.; Chudo, H.; Ono, M.; Harii, K.; Matsuo, M.; Maekawa, S.; Saitoh, E.


    We develop the in situ magnetization measurement apparatus for observing the Barnett effect consisting of a fluxgate sensor, a high speed rotor with frequencies of up to 1.5 kHz, and a magnetic shield at room temperature. The effective magnetic field (Barnett field) in a sample arising from rotation magnetizes the sample and is proportional to the rotational frequency. The gyroscopic g factor, g ' , of rare earth metals, in particular, Gd, Tb, and Dy, was estimated to be 2.00 ± 0.08, 1.53 ± 0.17, and 1.15 ± 0.32, respectively, from the slopes of the rotation dependence of the Barnett field. This study provides a technique to determine the g ' factor even in samples where the spectroscopic method may not be available.

  10. Parity Violation Experiments with Rare Earth Atoms

    Budker, Dmitry


    Since the first suggestions (V. A. Dzuba, V. V. Flambaum, and I. B. Khriplovich, Z. Phys. D1, 243 (1986).), (A. Gongora and P. G. H. Sandars, J. Phys. B 19, L291 (1986).) to search for parity violation in the rare earth atoms, experiments have been carried out by groups in Novosibirsk, Oxford, Hiroshima and Berkeley with Sm, Yb and Dy. The status of these experiments will be reviewed, with some details given on recent Berkeley Dy results ( A.-T. Nguyen, D. Budker, D. DeMille, and M. Zolotorev, Submitted to Phys. Rev. A.). Progress of the Berkeley Yb experiment ( D. DeMille, Phys. Rev. Lett. 74, 4165 (1995).), ( C.J. Bowers, D. Budker, E.D. Commins, D. DeMille, S.J. Freedman, A.-T. Nguyen, S.-Q. Shang, and M. Zolotorev, Phys. Rev. A 53, 3103-9(1996). ) will be described elsewhere at this meeting by C. J. Bowers et al.

  11. Magnetic anisotropies of rare-earth compounds

    Loewenhaupt, M.; Rotter, M.; Kramp, S.


    There are two kinds of magnetic anisotropy in rare-earth compounds: the single-ion anisotropy caused by the crystal field (CF) and the anisotropy of the two-ion interactions. Both types of anisotropy have to be considered to arrive at a consistent description of the magnetic properties of the orthorhombic intermetallic compound NdCu 2. From the analysis of NdCu 2 we can derive predictions for the type of ordering in other isostructural RCu 2 compounds, that agree well with experimental results: If the magnetic moments point into the crystallographic b-direction, an ordering wave vector of (2/3 0 0) is expected. If the moments are oriented perpendicular to b then the ordering wave vector is (2/3 1 0) .

  12. Social and Environmental Impact of the Rare Earth Industries

    Saleem H. Ali


    Full Text Available The use of rare earth elements in various technologies continues to grow despite some alternatives being found for particular uses. Given a history of ecological concerns about pollution from rare earth mines, particularly in China, there are growing social and environmental concerns about the growth of the mining and mineral processing in this sector. This is best exemplified by the recent social and environmental conflict surrounding the development of the Lynas Advanced Materials Plant (LAMP in Kuantan, Malaysia which led to international activism and claims of environmental and social injustice. This paper analyses the structure of environmental and social conflicts surrounding rare earth minerals and opportunities for improving the social and environmental performance of the sector. Many of these elements are used for green technologies. Opportunities exist that offer a more circular supply chain following industrial ecological principles through which reuse and recycling of the materials can provide a means of mitigating social and environmental conflicts in this sector. In addition, public engagement processes that recognize community concerns about radiation, and transparent scientifically predicated decision-making through an appropriate governance structure within regulatory organizations are also presented.

  13. The MIIT Again Urged to Set Up Large Rare Earth Groups


    <正>According to the"Economic Operation of The Rare Earth Industry in 2013"public notice published by the Ministry of Industry and Information Technology,speeding up the establishment of large rare earth enterprise group was placed at conspicuous position.Recently,the Department of Raw Materials,Ministry of Industry and Information

  14. Opinions on hot discussions in connection with rare earths recently

    SONG Hongfang; HONG Mei


    @@ Rare earth industry, with production value less than 30 trillion yuan, has become the hot topic both inside China and in the rest of the world since 2009. Even in stock market, rare earth was one of the most active sectors. Media in various countries, specialists in different fields and many political figures worldwide as well as some netizens showed extraordinary concerns on rare earths. Many heated arguments were made on the hot and even some sensitive topics about rare earth industry. Rare earth issues seem to be beyond the industrial production today, but the subject focused on economy, politics and strategic importance. The word "rare earth" was a yearly hot point or a key word in 2010.

  15. Study on Mechanism of Rare Earth PVC Stabilizer

    彭振博; 胡斌; 苏庆德; 曲锦忠


    Rare earth compounds can be used as PVC thermal stabilizers. According to the infrared spectra of the mixture of PVC and some stearates, the mechanism of stabilization of different stearates was studied. The specialty of rare earth stabilizers was found. They can change the conformation of PVC and restrain the elimination of HCl. From this aspect, the unique synergetic effect with other stabilizers of rare earth compounds can be explained.

  16. GRNM Likely to Spearhead Reshuffle of Guangdong Rare Earth Industry


    <正>"Guangdong intends to build a rare earth platform named Guangdong Rare Earth Group, and the plan has been probably approved recently." An insider of local government said, "although there is no final conclusion, but the Guangdong’s intention to build a general platform of rare earth is clear." Since Guangdong Rising Nonferrous Metals Group Co., Ltd. (GRNM) is the only local state-owned enterprise leading

  17. China Limits the Mining Quantity of Tungsten and Rare Earth


    <正>Based on a notice issued by the Ministry of Land Resources, China’s tungsten mining quantity in 2006 will be controlled to 59,060 tons in concentrates form, which include 4,250 tons of recycled tungsten. And the rare earth mining quantity in 2006 will also be controlled to 86,620 tons (REO) including 8,320 tons of heavy rare earth and 78,200 tons of light rare earth.

  18. Study on Copolymerization of Rare Earth-Carboxylic Acid Complex

    Qiu Guanmin(邱关明); Zhang Ming(张明); Yan Chang hao(严长浩); Zhou Lanxiang(周兰香); Dai Shaojun(戴少俊); Okamo to Hiroshi


    Complex of rare earth with carboxylic acid was prepared by precipita tion and direct method. It was copolymerized with such monomers as acrylic acid and other ones to synthesize ionomer of rare earth and organic polymer with different rare earth contents. Its glass-transition temperature and heat stability were analyzed by TG and DTA. Infra-red detector was used to show its structure. The effect of rare earth complex prepared by different methods on copolymerization and properties of copolymers was also discussed.

  19. Storing Solar Energy Performance on Rare Earth Windowpane

    Li Baojun; Zhou Yao; Fu Li; Yang Tao; Li Tiansi; Li Ying


    The windowpane as the enclosure and decorative component of buildings is main part of energy consumption and the heat loss through window is almost 4% of the heating consumption in buildings. Using rare earth element,the glass can possess the performance of absorbing sunlight, storing heat, increasing the temperate of itself, and decreasing the inner heat load so as to play the double functions of saving energy and environmental protection. The experiment method of the rare earth windowpane, and analyses sunlight absorbing process of the rare earth element on photoelectric principle, and gives the changing curve with environment temperate -time of the rare earth windowpane surface were introduced.

  20. The Rare Earth Magnet Industry and Rare Earth Price in China

    Ding Kaihong


    Full Text Available In the past four years, the price of rare earth metal fluctuates sharply for many reasons. Currently, it has become more stable and more reasonable. This presentation is focused on the effect about the rare earth metal price. Some motor manufacturers have shifted from rare earth permanent magnet to ferrite magnet. Many motor manufacturers changed the design for the motor cooling system to make the motor function at a lower temperature. Thus the consumption of Dy can be markedly reduced. As for manufacturer of NdFeB magnet, we are also trying to optimize our process to reduce to dependence of HREE such as Dy and Tb. HS process have been introduced to solve the problem. With more and more people focusing and engaging on the REE industry, the price of REE will be more transparent without too many fluctuations. China is considering the problems of balancing the environment, energy sources, and labor sources. The application field about NdFeB such as wind turbine generator, HEV/EV, FA /OA is flourishing.

  1. Properties of rare-earth iron garnets from first principles

    Nakamoto, Ryan; Xu, Bin; Xu, Changsong; Xu, Hu; Bellaiche, L.


    Structural and magnetic properties of rare-earth iron garnets (RIG), which contain 160 atoms per unit cell, are systematically investigated for rare-earth elements varying from La to Lu (and including Y), by performing spin polarized density-functional calculations. The effects of 4 f electrons (as core or as valence electrons) on the lattice constant, internal coordinates, and bond lengths are found to be rather small, with these predicted structural properties agreeing rather well with available experiments. On the other hand, treating such electrons as valence electrons is essential to interpret the total magnetization measured in some RIG at low temperature, the different orientation and magnitude of the magnetizations that Fe and rare-earth ions can adopt and to also explain why some RIG have a compensation temperature while others do not. The magnetic exchange couplings and orbital-projected density of states are also reported for two representative materials, namely Gd3Fe5O12 and Nd3Fe5O12 , when accounting for their 4 f electrons.

  2. Rare earth-ruthenium-magnesium intermetallics

    Stein, Sebastian; Kersting, Marcel; Heletta, Lukas; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie


    Eight new intermetallic rare earth-ruthenium-magnesium compounds have been synthesized from the elements in sealed niobium ampoules using different annealing sequences in muffle furnaces. The compounds have been characterized by powder and single crystal X-ray diffraction. Sm{sub 9.2}Ru{sub 6}Mg{sub 17.8} (a=939.6(2), c=1779(1) pm), Gd{sub 11}Ru{sub 6}Mg{sub 16} (a=951.9(2), c=1756.8(8) pm), and Tb{sub 10.5}Ru{sub 6}Mg{sub 16.5} (a=942.5(1), c=1758.3(4) pm) crystallize with the tetragonal Nd{sub 9.34}Ru{sub 6}Mg{sub 17.66} type structure, space group I4/mmm. This structure exhibits a complex condensation pattern of square-prisms and square-antiprisms around the magnesium and ruthenium atoms, respectively. Y{sub 2}RuMg{sub 2} (a=344.0(1), c=2019(1) pm) and Tb{sub 2}RuMg{sub 2} (a=341.43(6), c=2054.2(7) pm) adopt the Er{sub 2}RuMg{sub 2} structure and Tm{sub 3}Ru{sub 2}Mg (a=337.72(9), c=1129.8(4) pm) is isotypic with Sc{sub 3}Ru{sub 2}Mg. Tm{sub 3}Ru{sub 2}Mg{sub 2} (a=337.35(9), c=2671(1) pm) and Lu{sub 3}Ru{sub 2}Mg{sub 2} (a=335.83(5), c=2652.2(5) pm) are the first ternary ordered variants of the Ti{sub 3}Cu{sub 4} type, space group I4/mmm. These five compounds belong to a large family of intermetallics which are completely ordered superstructures of the bcc subcell. The group-subgroup scheme for Lu{sub 3}Ru{sub 2}Mg{sub 2} is presented. The common structural motif of all three structure types are ruthenium-centered rare earth cubes reminicent of the CsCl type. Magnetic susceptibility measurements of Y{sub 2}RuMg{sub 2} and Lu{sub 3}Ru{sub 2}Mg{sub 2} samples revealed Pauli paramagnetism of the conduction electrons.

  3. Rare-earth metal prices in the USA ca. 1960 to 1994

    Hedrick, James B.


    Rare-earth metal prices were compiled from the late 1950s and early 1960s through 1994. Although commercial demand for rare-earth metals began in 1908, as the alloy mischmetal, commercial quantities of a wide range of individual rare-earth metals were not available until the late 1950s. The discovery of a large, high-grade rare-earth deposit at Mountain Pass. CA, USA, in 1949, was significant because it led to the production of commercial quantities or rare-earth elements that reduced prices and encouraged wider application of the materials. The availability of ore from Mountain Pass, and other large rare-earth deposits, especially those in Australia and China, has provided the world with abundant resources for rare-earth metal production. This availability, coupled with improved technology from Government and private-sector metallurgical research, has resulted in substantial decreases in rare-earth metal prices since the late 1950s and early 1960s. Price series for the individual rare-earth metals (except promethium) are quoted on a kilogram basis from the late 1950s and early 1960s through 1994. Prices are given in US dollars on an actual and constant dollar basis. Industrial and economic factors affecting prices during this time period are examined.

  4. Rare-earth doped (alpha'/beta')-sialon ceramics

    Gajum, N R


    combination of light and heavy rare-earth (Yb-Nd and Gd-Nd), and then pressureless sintered and compared with the single cation materials. Materials in the as sintered state were composed of a high alpha' sialon content with a minor amount of beta' sialon and 12H A1N polytype indicating that the heavy rare-earth (which is the principal alpha' stabilizer) has a dominant effect although EDAX analysis confirmed the presence of both cations (light and heavy) within the alpha' structure. The research also compared, and developed an understanding of, the thermal stability of alpha'-sialon using single Yb or mixed cations. The Yb single cation alpha'/beta' materials exhibited excellent stability over a range of temperature (1200 - 1600 deg C) and for different periods of time up to 168 hrs. The heat treatments result in the crystallisation of the residual phase as a Yb garnet phase which formed at approx 1300 deg C. The mixed cation alpha'/beta' materials showed some alpha'-beta' transformation. The transformation w...

  5. Multicomponent, Rare-Earth-Doped Thermal-Barrier Coatings

    Miller, Robert A.; Zhu, Dongming


    Multicomponent, rare-earth-doped, perovskite-type thermal-barrier coating materials have been developed in an effort to obtain lower thermal conductivity, greater phase stability, and greater high-temperature capability, relative to those of the prior thermal-barrier coating material of choice, which is yttria-partially stabilized zirconia. As used here, "thermal-barrier coatings" (TBCs) denotes thin ceramic layers used to insulate air-cooled metallic components of heat engines (e.g., gas turbines) from hot gases. These layers are generally fabricated by plasma spraying or physical vapor deposition of the TBC materials onto the metal components. A TBC as deposited has some porosity, which is desirable in that it reduces the thermal conductivity below the intrinsic thermal conductivity of the fully dense form of the material. Undesirably, the thermal conductivity gradually increases because the porosity gradually decreases as a consequence of sintering during high-temperature service. Because of these and other considerations such as phase transformations, the maximum allowable service temperature for yttria-partially stabilized zirconia TBCs lies in the range of about 1,200 to 1,300 C. In contrast, the present multicomponent, rare-earth-doped, perovskite-type TBCs can withstand higher temperatures.

  6. Accumulation of rare earth elements by siderophore-forming Arthrobacter luteolus isolated from rare earth environment of Chavara, India

    E S Challaraj Emmanuel; T Ananthi; B Anandkumar; S Maruthamuthu


    In this study, Arthrobacter luteolus, isolated from rare earth environment of Chavara (Quilon district, Kerala, India), were found to produce catechol-type siderophores. The bacterial strain accumulated rare earth elements such as samarium and scandium. The siderophores may play a role in the accumulation of rare earth elements. Catecholate siderophore and low-molecular-weight organic acids were found to be present in experiments with Arthrobacter luteolus. The influence of siderophore on the accumulation of rare earth elements by bacteria has been extensively discussed.

  7. Research trends in rare earths: A preliminary analysis



    The research trend in rare earths has been studied using the Chemical Abstracts (CA) data.The number of papers published from China has been increasing very rapidly since 2001 and today China is the top country in terms of paper contribution on rare earths.This article presents a comparative study of R & D trends among China,Japan and USA.

  8. Rare earth element enrichment using membrane based solvent extraction

    Makertiharta, I. G. B. N.; Dharmawijaya, P. T.; Zunita, M.; Wenten, I. G.


    The chemical, catalytic, electrical, magnetic, and optical properties of rare earth elements are required in broad applications. Rare earth elements have similar physical and chemical properties thus it is difficult to separate one from each other. Rare earth element is relatively abundant in earth's crust but rarely occur in high concentrated deposits. Traditionally, ion-exchange and solvent extraction techniques have been developed to separate and purify single rare earth solutions or compounds. Recently, membrane starts to gain attention for rare earth separation by combining membrane and proven technologies such as solvent extraction. Membrane-based process offers selective, reliable, energy efficient and easy to scale up separation. During membrane-based separation process, one phase passes through membrane pores while the other phase is rejected. There is no direct mixing of two phases thus the solvent loss is very low. Membrane can also lower solvent physical properties requirement (viscosity, density) and backmixing, eliminate flooding phenomenon and provide large interfacial area for mass transfer. This paper will summarize research efforts in developing membrane technology for rare earth element separation. Special attention will be given to solvent extraction related process as the commonly used method for rare earth element separation. Furthermore, membrane configuration and its potentials will also be discussed.

  9. Shanghai Rare Earth Industry Scale is Expected to Double


    <正>A new organization in the rare earth industry circle in Shanghai initiated and set up by 14 enterprises and public institutions called "Shanghai Rare Earth Association", formally declared its establishment recently. This marked China’s only specialized and non-profit

  10. Imports εt Exports Review of Chinese Rare Earths


    @@ China developed herself from being predominant at RE resources into a country with the largest production, the highest export volume and the largest application of rare earth products in the world. Today, China plays a leading role in the global rare earth market.

  11. Review and outlook of 2008 China rare earth market

    ZHANG Lihua


    @@ I.Environment and trend of RE market 1.Operation environment in 2008 Chinese government further strengthened its macro-control on rare earth industry in 2008.Mandatory planning policy was implemented in the production of rare earth minerals and smelted products.

  12. China Aluminum Guangxi Nonferrous Rare Earth Mining Company Limited was Founded


    <正>The China Aluminum Guangxi Non-ferrous Rare Earth Mining Company Limited co-built by Aluminium Corporation of China,Guangxi Non-ferrous Metal Group Company Limited,and Grirem Advanced Materials Co.,Ltd.was

  13. Rare earth silicide nanowires on silicon surfaces

    Wanke, Martina


    The growth, structure and electronic properties of rare earth silicide nanowires are investigated on planar and vicinal Si(001) und Si(111) surfaces with scanning tunneling microscopy (STM), low energy electron diffraction (LEED) and angle-resolved photoelectron spectroscopy (ARPES). On all surfaces investigated within this work hexagonal disilicides are grown epitaxially with a lattice mismatch of -2.55% up to +0.83% along the hexagonal a-axis. Along the hexagonal c-axis the lattice mismatch is essentially larger with 6.5%. On the Si(001)2 x 1 surface two types of nanowires are grown epitaxially. The socalled broad wires show a one-dimensional metallic valence band structure with states crossing the Fermi level. Along the nanowires two strongly dispersing states at the anti J point and a strongly dispersing state at the anti {gamma} point can be observed. Along the thin nanowires dispersing states could not be observed. Merely in the direction perpendicular to the wires an intensity variation could be observed, which corresponds to the observed spacial structure of the thin nanowires. The electronic properties of the broad erbium silicide nanowires are very similar to the broad dysprosium silicide nanowires. The electronic properties of the DySi{sub 2}-monolayer and the Dy{sub 3}Si{sub 5}-multilayer on the Si(111) surface are investigated in comparison to the known ErSi{sub 2}/Si(111) and Er{sub 3}Si{sub 5}/Si(111) system. The positions and the energetic locations of the observed band in the surface Brillouin zone will be confirmed for dysprosium. The shape of the electron pockets in the (vector)k {sub parallel} space is elliptical at the anti M points, while the hole pocket at the anti {gamma} point is showing a hexagonal symmetry. On the Si(557) surface the structural and electronic properties depend strongly on the different preparation conditions likewise, in particular on the rare earth coverage. At submonolayer coverage the thin nanowires grow in wide areas

  14. Rare earth elements in Hamersley BIF minerals

    Alibert, Chantal


    Minerals from the Hamersley banded iron formation, Western Australia, were analyzed for Y and rare earth elements (YREEs) by laser ablation ICP-MS to investigate diagenetic pathways, from precursor phases to BIF minerals. One group of apatites carries the seawater REE signature, giving evidence that P and REEs, thoroughly scavenged from the water column by Si-ferrihydrite particles, were released upon microbial Fe3+ reductive dissolution of Si-ferrihydrite in pore-water and finally sequestered mainly in authigenic apatite. The absence of fractionation between apatite and seawater suggests that REE were first incorporated into an amorphous calcium phosphate as fully hydrated cations, i.e. as outer-sphere complexes. The iron oxides and carbonates carry only a small fraction of the whole-rock REE budget. Their REE patterns are distinctly enriched in Yb and show some M-type tetrad effect consistent with experimental Kd(REE) between solid and saline solution with low carbonate ion concentrations. It is deduced that hematite formed at an incipient stage of Fe2+-catalyzed dissolution of Si-ferrihydrite, via a dissolution-reprecipitation pathway. The REE pattern of greenalite, found as sub-micron particles in quartz in a chert-siderite sample, is consistent with its authigenic origin by precipitation in pore-water after dissolution of a small amount of Si-ferrihydrite. Magnetite carries very low YREEs (ppb-level), has an homogeneous pattern distinctly enriched in the mid-REEs compared to hematite, and includes a late population depleted in light-REEs, Ba and As. Magnetite forming aggregates and massive laminae is tentatively interpreted as reflecting some fluid-aided hematite-magnetite re-equilibration or transformation at low-grade metamorphic temperatures.

  15. 稀土锆酸盐热障涂层材料研究进展%Research Progresses of Rare-Earth Zirconate Ceramic Materials for Thermal Barrier Coatings

    项建英; 陈树海; 黄继华; 周国栋; 梁文建; 汪瑞军; 何箐


    稀土锆酸盐是最有希望应用于未来高性能航空发动机的热障涂层材料之一.归纳了国内外研究者在稀土锆酸盐类陶瓷材料上取得的结果,系统分析了不同位置全取代或部分取代得到的掺杂陶瓷材料的热物理性能和力学性能,并讨论了热障涂层材料研究的发展趋势,最后指出了稀土高酸盐热障涂层材料需要进一步研究的关键问题.%Rare-earth zirconates is one of the prospective thermal barrier coatings (TBCs) materials for use in high performance turbine engine in the future. The research progress of home and abroad is summarized, and the ther-mo-physical and mechanical properties of ceramic materials which substituted by completely or partly at different elements were analyzed systematically. The research progress and development tendency of ceramic materials for TBCs are analyzed and investigated, and then some key problems of rare-earth zirconates as TBCs materials in further reac-her are reviewed in the end.

  16. Some Rare Earth Metallic Organohydrides with Biindenyl as the Ligand


    @@ Introduction It is well known that organometallic hydrides of rare earth metals are the catalysts and reducing reagents for the catalysis polymerization of alkenes and the catalysis hydrogenation of alkenoalkynes. There are four methods for the syntheses of organometallic hydrides of rare earth metals: (1) the thermal atomization of metals, I. E. , the interaction of a rare earth metal with alkenes with a terminal alkyne; (2) the Ln-C σ bond is broken with H2; (3) metallic hydride replacement[1], I. E., NaBH4, LiA1H4 and Na can be used to react with organometallic compounds of rare earth metals; (4) the elimination ofβ-H, I. E. , in the presence of LiC1, the elimination of theβ-H of the alkyl compounds of rare earth metals gives the target product. The organohydrides of biindenyl samarium, biindenyl gadolinium and biin denyl dysprosium were obtained with NaH reduction method.

  17. Studies on solid phase synthesis,characterization and fluorescent property of the new rare earth complexes

    Shi, Jianwei; Xiaoxu TENG; Wang, Linling; Long, Rong


    Rare earth-β-diketone ligand complex luminescent material has stable chemical properties and excellent luminous property. Using europium oxide and (γ-NTA) as raw materials, novel rare earth-β-dione complexes are synthesized by solid state coordination chemistry. The synthesis temperature and milling time are discussed for optimization. Experimental results show that the suitable reaction situation is at 50 ℃ and 20 h for solid-phase synthesis. The compositions and structures of the complexes...

  18. Preparation and Easy-Cleaning Property of Rare Earth Composite Ceramic


    Rare earth and far-infrared mineral composite materials were added to ceramic glazes to prepare easy-cleaning ceramic. The morphology of easy-cleaning ceramic was observed by SEM. The influence of easy-cleaning ceramic on water surface tension and contact angles of water were investigated. Through calculation of ceramic surface free energy and observation of oil drop on ceramic surface in water, the easy-cleaning mechanism of rare earth composite ceramic was studied. It is found that the rare earth composite ceramic can make water surface tension decrease. The surface free energy and the polar component of rare earth composite ceramic are increased. The rare earth composite ceramics have the easy-cleaning property.

  19. Method for determination of small amounts of rare earths and thorium in phosphate rocks

    Waring, C.L.; Mela, H.


    In laboratory investigations, interest developed in the possible rare-earth content of phosphate samples from Florida and the northwestern United States. Because of the difficulty of making chemical determinations of traces of individual rare earths, a combined chemical-spectrographic method was investigated. After removal of iron by the extraction of the chloride with ether, the rare earths and thorium are concentrated by double oxalate precipitation, using calcium as a carrier. The rare earths are freed from calcium by an ammonium hydroxide precipitation with a fixed amount of aluminum as a carrier. The aluminum also serves as an internal standard in the final spectrographic analysis. The method will determine from 0.02 to 2 mg. of each rare earth with an error no greater than 10%. The investigation has resulted in a fairly rapid and precise procedure, involving no special spectrographic setup. The method could be applied to other types of geologic materials with the same expected accuracy.

  20. Forms of Rare Earth Elements in Soils:II.Differentiation of Rare Earth Elements



    The present paper deals mainly with the relationships between the distribution of rare earth elements (REE) in different forms in soils and the atomic number and with the odd-even phenomenon in the distribution of ionic lanthanides in soils.The enrichment tendency of light REE relative to heavy REE in soils was pointed out on the experimental results about the proportions of Ce-group and Y-group elements in different REE forms in soils.Meanwhile,the differentiation of Tm in different soil REE forms was compared and the reasons why Tm is enriched in soils were preliminarily discussed.

  1. Transferred hyperfine interaction between the rare-earth ions and the fluorine nuclei in rare-earth trifluorides

    Hansen, P. E.; Nevald, Rolf; Guggenheim, H. G.


    The isotropic and anisotropic transferred hyperfine interactions between F ions in the two chemically inequivalent sites and the rare-earth ions (R) have been derived from 19F NMR measurements in the temperature region 100-300 K on single crystals of TbF3 and DyF3. The isotropic interactions...... are found to be negative and constant in this temperature region and with the numerical values decreasing slightly from TbF3 to DyF3. The anisotropic interactions, when the point dipole contributions are subtracted, are found to be substantially smaller and about equal for the two materials. The crystals...

  2. Status of Research on Application of High Purity Rare Earth Oxides in Solid Oxide Fuel Cells

    Ma Zhihong; Qiu Jufeng


    The solid oxide fuel cell (SOFC) is a high-efficient and environmentally friendly power generation system.The rare earth oxide materials are used extensively in the manufacturing of SOFC components.In particular, the CeO2doped with Gd2O3 or Sm2O3, lanthanide perovskite oxides are indispensable and key materials for developing the intermediate temperature SOFC.The research and development status of application of high purity rare earth oxides in SOFC was overviewed.The rare earth oxide-based and -doped materials were discussed for the SOFC components.Concerning the rare earth oxides applicable to SOFC, several topics were also pointed out for further researching and developing.

  3. Rare Earth Elements in Global Aqueous Media

    Noack, C.; Karamalidis, A.; Dzombak, D. A.


    We are examining the occurrence and abundance of rare earth elements (REE) associated with produced waters from shale gas development, and factors controlling aqueous REE concentrations in geochemical environments, to provide information for: (1) potential recovery of REE as a valuable byproduct, and (2) utilization of unique REE signatures as a risk assessment tool. REE include the lanthanide series of elements - excluding short-lived, radioactive promethium - and yttrium. These elements are critical to a wide variety of high-tech, energy efficient applications such as phosphors, magnets, and batteries. Escalating costs of REE resulting from divergent supply and demand patterns motivates the first goal. The second goal relates to the search for a reliable, naturally occurring tracer to improve understanding of fluid migration and water-rock interactions during hydraulic fracturing and natural gas recovery. We compiled data from 100 studies of REE occurrence and concentrations in groundwaters, ocean waters, river waters, and lake waters. In the groundwater systems documented, total dissolved REE concentrations ranged over eight orders of magnitude; however the average concentrations across the lanthanides varied by less than two orders of magnitude. This leads to exceptional inter-element correlations, with a median correlation coefficient greater than 0.98, implying potential usefulness of REE ratios for groundwater signatures. Reports describing reactions governing REE solubilization were also investigated. We assembled information about important solution chemistries and performed equilibrium modeling using PHREEQC to examine common hypotheses regarding the factors controlling REE compositions. In particular, effects of pH, Eh, and common complexing ligands were evaluated. Produced and connate waters of the Marcellus shale are well characterized for their major chemical elements. There is a dearth of knowledge, however, regarding the occurrence of REE in

  4. The Development Status and Trends of Optical Functional Materials in China’ s Rare Earth Industry%稀土光功能材料产业发展现状与趋势



    稀土是功能性材料、战略物资的源头,光与色的精灵,稀土“应用”是科技创新、自主知识产权、原创核心技术的精髓。在研发生产全面提升高效灯用稀土三基色、多组份荧光粉的同时,需加快对白光LED照明用蓝光和紫外激发的黄色、橙色、红色、深红色、绿色、蓝绿色、蓝色荧光粉和新型宽色域、高密度、全光谱荧光粉以及EL、OEL、OLED、稀土配合物、荧光染料、量子点纳米晶、荧光微晶玻璃、透明陶瓷荧光材料的研制开发和产业化,进一步加强自主知识产权保护和应用创新的力度。%Rare earth is the functional material, the source of strategic materials, elves of light and color.“Application” of rare earth is the essence of science and technology innovation, intellectual property rights, and the original core technology.In the R & D to enhance the efficient use of rare earth trichromatic lamp, multi-component phosphor, while the need to speed up the research and development and industrialization of white LED lighting with blue and ultraviolet excitation of yellow, orange, red, dark red, green, blue and green, blue phosphors and a new wide color gamut, high-density, full-spectrum fluorescent and EL, OEL, OLED, rare earth complexes, fluorescent dyes, quantum dot nanocrystals, fluorescent glass ceramics, transparent ceramic fluorescent materials, and further strengthen independent IPR protection and application innovation.


    F.S. Chen; Y.X. Liu; D.K. Liang; L.M. Xiao


    The microstructure of plasma nitrided layer catalyzed by rare-earth elements has beenstudied with TEM. The results show that the grains of γ'-Fe4N phase are refinedby rare-earth elements and the plane defects in boundary are increased by rare-earthelements. The addition of rare-earth element increases the bombardment effect andthe number of crystal defects such as vacancies, dislocation loops, twins and stackingfaults in γ'-Fe4N phase and can produce the high-density dislocations in the ferrite ofdiffusion layer at a distance 0. 08mm from the surface. The production of a numberof crystal defects is one of important reasons why rare-earth element accelerates thediffusion of nitrogen atoms during plasma-nitridiug.

  6. Bioleaching of rare earth elements from monazite sand.

    Brisson, Vanessa L; Zhuang, Wei-Qin; Alvarez-Cohen, Lisa


    Three fungal strains were found to be capable of bioleaching rare earth elements from monazite, a rare earth phosphate mineral, utilizing the monazite as a phosphate source and releasing rare earth cations into solution. These organisms include one known phosphate solubilizing fungus, Aspergillus niger ATCC 1015, as well as two newly isolated fungi: an Aspergillus terreus strain ML3-1 and a Paecilomyces spp. strain WE3-F. Although monazite also contains the radioactive element Thorium, bioleaching by these fungi preferentially solubilized rare earth elements over Thorium, leaving the Thorium in the solid residual. Adjustments in growth media composition improved bioleaching performance measured as rare earth release. Cell-free spent medium generated during growth of A. terreus strain ML3-1 and Paecilomyces spp. strain WE3-F in the presence of monazite leached rare earths to concentrations 1.7-3.8 times those of HCl solutions of comparable pH, indicating that compounds exogenously released by these organisms contribute substantially to leaching. Organic acids released by the organisms included acetic, citric, gluconic, itaconic, oxalic, and succinic acids. Abiotic leaching with laboratory prepared solutions of these acids was not as effective as bioleaching or leaching with cell-free spent medium at releasing rare earths from monazite, indicating that compounds other than the identified organic acids contribute to leaching performance.

  7. [Content of rare earth elements in wild Hypericum japonicum Thunb].

    Wei, Zhen-Lin; Rui, Yu-Kui; Tian, Zhi-Huan


    Rare earth elements are important nutritional elements for human health, and today more and more attention has been paid to the effective components in Chinese traditional medicine, especially to rare earth elements. Fifteen rare earth elements in wild hypericum japonicum Thunb were analyzed by the methods of ICP-MS. The results showed that the concentrations of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Tm, Lu and Y ranged from 6 ng x g(-1) x DW to 14 522 ng x g(-1) x DW, and among them the concentrations of La, Ce and Nd were higher than 2 000 ng x g(-1) x DW. Compared with the concentration of rare earth elements in rice, corn, wheat and barley, the total concentration of rare earth elements in hypericum japonicum Thunb was much higher, which could be the mechanism of curative effect of hypericum japonicum Thunb on liverish diseases. The character of elements and the content of rare earth elements in soil should be responsible for the difference, but the distributive mechanism of rare earth elements in hypericum japonicum Thunb should be further studied.

  8. Study on Competitive Power of Rare Earth Industry in China

    Qian Jiuhong; Li Guoping


    China is abundant of rare earth resources, it has been the biggest producer, consumer and supplier. The superiority and the scale within the last 40 years make it possible to develop China's rare earth industry in a higher degree.But the superiority of rare earth resources has not turned into the economic superiority, and the development of rare earth industry in China with high speed does not lead to high benefits. Therefore, it has become the hot point and vital task now how to resolve the main problems of rare earth industry in China and how to make its rare earth industry grow healthily and steadily through transforming resources, adjusting structure, escalating industry, bringing forth new ideas in technology. This article aims at analyzing the competitive power of China's rare earth industry in the application of "Diamond framework, Determinants of National Advantage" written by Michael Porter, the well-known economist,based on the analysis, the author puts forward a strategic proposal to raise the competitive power.

  9. 75 FR 25293 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Rare Earth...


    ... materials and products beginning with extraction of rare earths and ending with marketing and sale of such... earth products and technology to enhance the U.S. military's war fighting capabilities for the...

  10. Effects of rare-earth co-doping on the local structure of rare-earth phosphate glasses using high and low energy X-ray diffraction.

    Cramer, Alisha J; Cole, Jacqueline M; FitzGerald, Vicky; Honkimaki, Veijo; Roberts, Mark A; Brennan, Tessa; Martin, Richard A; Saunders, George A; Newport, Robert J


    Rare-earth co-doping in inorganic materials has a long-held tradition of facilitating highly desirable optoelectronic properties for their application to the laser industry. This study concentrates specifically on rare-earth phosphate glasses, (R2O3)x(R'2O3)y(P2O5)(1-(x+y)), where (R, R') denotes (Ce, Er) or (La, Nd) co-doping and the total rare-earth composition corresponds to a range between metaphosphate, RP3O9, and ultraphosphate, RP5O14. Thereupon, the effects of rare-earth co-doping on the local structure are assessed at the atomic level. Pair-distribution function analysis of high-energy X-ray diffraction data (Q(max) = 28 Å(-1)) is employed to make this assessment. Results reveal a stark structural invariance to rare-earth co-doping which bears testament to the open-framework and rigid nature of these glasses. A range of desirable attributes of these glasses unfold from this finding; in particular, a structural simplicity that will enable facile molecular engineering of rare-earth phosphate glasses with 'dial-up' lasing properties. When considered together with other factors, this finding also demonstrates additional prospects for these co-doped rare-earth phosphate glasses in nuclear waste storage applications. This study also reveals, for the first time, the ability to distinguish between P-O and P[double bond, length as m-dash]O bonding in these rare-earth phosphate glasses from X-ray diffraction data in a fully quantitative manner. Complementary analysis of high-energy X-ray diffraction data on single rare-earth phosphate glasses of similar rare-earth composition to the co-doped materials is also presented in this context. In a technical sense, all high-energy X-ray diffraction data on these glasses are compared with analogous low-energy diffraction data; their salient differences reveal distinct advantages of high-energy X-ray diffraction data for the study of amorphous materials.

  11. Radiological Impacts and Regulation of Rare Earth Elements in Non-Nuclear Energy Production

    Timothy Ault


    Full Text Available Energy industries account for a significant portion of total rare earth usage, both in the US and worldwide. Rare earth minerals are frequently collocated with naturally occurring radioactive material, imparting an occupational radiological dose during recovery. This paper explores the extent to which rare earths are used by various non-nuclear energy industries and estimates the radiological dose which can be attributed to these industries on absolute and normalized scales. It was determined that typical rare earth mining results in an occupational collective dose of approximately 0.0061 person-mSv/t rare earth elements, amounting to a total of 330 person-mSv/year across all non-nuclear energy industries (about 60% of the annual collective dose from one pressurized water reactor operated in the US, although for rare earth mining the impact is spread out over many more workers. About half of the collective dose from non-nuclear energy production results from use of fuel cracking catalysts for oil refining, although given the extent of the oil industry, it is a small dose when normalized to the energy equivalent of the oil that is used annually. Another factor in energy industries’ reliance on rare earths is the complicated state of the regulation of naturally occurring radiological materials; correspondingly, this paper also explores regulatory and management implications.

  12. Advances on Rare Earth Application in Pollution Ecology

    Huang Xiaohua; Zhou Qing; Zhang Guangsheng


    The use of rare earth for inducing plant resistance was reviewed. The important developments in recent years were described, and rare earth can alleviate the pollution of acid rain, ozone, pesticide, heavy metals etc. in environment. The authors suggest that the mechanism of rare earth to inducing plant resistance and reducing plant injury is to control biochemical metabolism web in plant cell, to adjust its protection system of free radical, to maintain its photosynthesis, to protect cell membrane system and to carry through its function on mineral metabolism. Meanwhile some problems in the field were discussed as well.

  13. Review and forecast of China rare earth industry (continued)


    @@ 3. Current rare earth export situation a. RE export enterprises To further strengthen administration on export of rare earths and standardize export system, the Ministry of Commerce instituted the "Qualification Standards and Application Procedures for Rare Earth Export Enterprises" in 2006, which regulated the export from production capacity, technologies, safety & environmental protection and credit of enterprises, hence to standardize the export system. There were 47 RE export enterprises announced in common trade in 2006, while it dropped to 41 ones in 2007 and 25 in 2008. There were merely 23 export enterprises in 2009.

  14. Thermal Oxidation Resistance of Rare Earth-Containing Composite Elastomer

    邱关明; 张明; 周兰香; 中北里志; 井上真一; 冈本弘


    The rare earth-containing composite elastomer was obtained by the reaction of vinyl pyridine-SBR (PSBR) latex with rare earth alkoxides, and its thermal oxidation resistance was studied. After aging test, it is found that its retention rate of mechanical properties is far higher than that of the control sample. The results of thermogravimetric analysis show that its thermal-decomposing temperature rises largely. The analysis of oxidation mechanisms indicates that the main reasons for thermal oxidation resistance are that rare earth elements are of the utility to discontinue autoxidation chain reaction and that the formed complex structure has steric hindrance effect on oxidation.

  15. Separation of rare earth elements by tertiary pyridine type resin

    Suzuki, Tatsuya [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)]. E-mail:; Itoh, Keisuke [Graduate School of Material Science and Engineering, Shibaura Institute of Technology, Shibaura, Minato-ku, Tokyo 108-8584 (Japan); Ikeda, Atsushi [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Aida, Masao [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Ozawa, Masaki [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Oarai Engineering Center, Japan Nuclear Cycle Development Institute, Narita-machi, Oarai-machi, Higashiibaraki-gun, Ibaraki 311-1393 (Japan); Fujii, Yasuhiko [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)


    The novel separation method of rare earth elements by using the tertiary pyridine type resin with methanol and nitric acid mixed solution was developed. The separating operation in this method is very simple and easy, and the waste generation in this method is expected to be low. The adsorption and separation behaviors of rare earth elements were investigated with changing the nitric acid concentration, the methanol concentration, and the alcoholic species. It was confirmed that the rare earth elements can be well separated mutually.

  16. Magnetocaloric effect in rare-earth intermetallics: Recent trends

    R Nirmala; A V Morozkin; S K Malik


    Magnetocaloric effect (MCE) is the change in isothermal magnetic entropy (m)and adiabatic temperature (ad) that accompany magnetic transitions in materials during the application or the removal of magnetic field under adiabatic conditions. The physics of MCE gets enriched by correlated spin-lattice degrees of freedom. This phenomenon has been actively investigated over the past few decades as it holds a promise for an alternate method of refrigeration/heat pumping. This has already resulted in several reviews on this topic. This paper focusses on some recent trends in this field and prospects of using rare-earth-based materials as active magnetic refrigerants over a broad temperature range that includes gas liquefaction and near-room temperature refrigeration/heating.

  17. Geochemistry of Rare Earth Elements in Aktishikan Gold Deposit,Xinjiang

    袁峰; 周涛发; 等


    The characteristics and the models of rare earth elements in the geological bodies and the hydrothermal water balancel with the adamellite were comprehensivealy studied in Aktishikan gold deposit,Nurt area of Altay,Xinjiang,And the behavior of rare earth elements during metasomatic alteration was discussed by using the isocon method of Grant,The results show that the rare earth elements are inert during metasomatic alteration,the hydrotheraml water has no relation to the magmatic water,and the gold material sources mainly stem from the wall rock.

  18. Hydrothermal synthesis of mixed rare earth-alkali metal or ammonium fluorides

    由芳田; 黄世华; 时秋峰


    The recent results on hydrothermal synthesis of mixed rare earth-alkali or ammonium fluorides were presented. The initial ratios of the starting materials, pH value and reaction temperature were the critical factors for obtaining the single-phase product. Four main types of complex rare earth fluorides, AREF4, A2REF5, ARE2F7 and ARE3F10 (A=Na+, K+, Rb+, NH4+), appeared in the primary hydrothermal reactions. The correlation between cation sizes and the formation of mixed rare earth fluorides under mild hydro...

  19. A political economy of China's export restrictions on rare earth elements

    Pothen, Frank [Zentrum fuer Europaeische Wirtschaftsforschung GmbH (ZEW), Mannheim (Germany); Fink, Kilian [Frankfurt Univ. (Germany)


    We investigate why governments restrict exports of exotic raw materials taking rare earth elements as a case study. Trade restrictions on exotic materials do not have immediate macroeconomic effects. Relocating rare earth intensive industries is found to be the main reason behind China's export barriers. They are part of a more extensive strategy aiming at creating comparative advantages in these sectors and at overcoming path dependencies. Moreover, export barriers serve as a second-best instrument to reduce pollution and to slow down the depletion of exhaustible resources. Growing domestic rare earth consumption renders those increasingly ineffective. Rising reliance on mine-site regulation indicates that this fact is taken into account. Rare earth extraction is dominated by a few large companies; the demand side is dispersed. That speaks against successful lobbying for export restrictions. It appears as if the export barriers are set up to compensate mining firms.

  20. Bacterial Cell Surface Adsorption of Rare Earth Elements

    Jiao, Y.; Park, D.; Reed, D.; Fujita, Y.; Yung, M.; Anderko, A.; Eslamimanesh, A.


    Rare earth elements (REE) play a critical role in many emerging clean energy technologies, including high-power magnets, wind turbines, solar panels, hybrid/electric vehicle batteries and lamp phosphors. In order to sustain demand for such technologies given current domestic REE shortages, there is a need to develop new approaches for ore processing/refining and recycling of REE-containing materials. To this end, we have developed a microbially-mediated bioadsorption strategy with application towards enrichment of REE from complex mixtures. Specifically, the bacterium Caulobacter crescentus was genetically engineered to display lanthanide binding tags (LBTs), short peptides that possess high affinity and specificity for rare earth elements, on its cell surface S-layer protein. Under optimal conditions, LBT-displayed cells adsorbed greater than 5-fold more REE than control cells lacking LBTs. Competition binding experiments with a selection of REEs demonstrated that our engineered cells could facilitate separation of light- from heavy- REE. Importantly, binding of REE onto our engineered strains was much more favorable compared to non-REE metals. Finally, REE bound to the cell surface could be stripped off using citrate, providing an effective and non-toxic REE recovery method. Together, this data highlights the potential of our approach for selective REE enrichment from REE containing mixtures.

  1. Protonic conduction in rare earth orthophosphates with the monazite structure

    Kitamura, N.; Amezawa, K.; Yamamoto, N. [Graduate School of Human and Environmental Studies, Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); Tomii, Y. [Graduate School of Energy Science, Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan)


    Electrical conduction in rare earth orthophosphates, LnPO{sub 4} (Ln=La, Pr, Nd and Sm), with the monazite structure (P2{sub 1}/n) was investigated by using conductivity measurements at 500-925 C. From the conductivities of undoped and 1 mol% Sr-doped LnPO{sub 4} under wet (H{sub 2}O and D{sub 2}O) and dry atmospheres, it was found that LnPO{sub 4} began to conduct protons under wet atmosphere by substituting Sr for Ln. The conductivity behavior of 1 mol% Sr-doped LnPO{sub 4} versus p(H{sub 2}O) and p(O{sub 2}) was discussed in terms of the defect equilibria. It was concluded that protonic conduction was dominant in the materials though electron holes contributed slightly to the total conductivity as temperature increased. All the 1 mol% Sr-doped LnPO{sub 4} investigated in this study exhibited similar electrical conduction regardless of rare earth element used.

  2. Structural flexibility in magnetocaloric RE5T4 (RE=rare-earth; T=Si,Ge,Ga) materials: Effect of chemical substitution on structure, bonding and properties

    Misra, Sumohan [Iowa State Univ., Ames, IA (United States)


    The binary, ternary and multicomponent intermetallic compounds of rare-earth metals (RE) with group 14 elements (Tt) at the RE5Tt4 stoichiometry have been known for over 30 years, but only in the past decade have these materials become a gold mine for solid-state chemistry, materials science and condensed matter physics. It all started with the discovery of a giant magnetocaloric effect in Gd5Si2Ge2, along with other extraordinary magnetic properties, such as a colossal magnetostriction and giant magnetoresistance. The distinctiveness of this series is in the remarkable flexibility of the chemical bonding between well-defined, subnanometer-thick slabs and the resultant magnetic, transport, and thermodynamic properties of these materials. This can be controlled by varying either or both RE and Tt elements, including mixed rare-earth elements on the RE sites and different group 14 (or T = group 13 or 15) elements occupying the Tt sites. In addition to chemical means, the interslab interactions are also tunable by temperature, pressure, and magnetic field. Thus, this system provides a splendid 'playground' to investigate the interrelationships among composition, structure, physical properties, and chemical bonding. The work presented in this dissertation involving RE5T4 materials has resulted in the successful synthesis, characterization, property measurements, and theoretical analyses of various new intermetallic compounds. The results provide significant insight into the fundamental magnetic and structural behavior of these materials and help us better understand the complex link between a compound's composition, its observed structure, and its properties.

  3. Multilayer Thermal Barrier Coating (TBC) Architectures Utilizing Rare Earth Doped YSZ and Rare Earth Pyrochlores

    Schmitt, Michael P.; Rai, Amarendra K.; Bhattacharya, Rabi; Zhu, Dongming; Wolfe, Douglas E.


    To allow for increased gas turbine efficiencies, new insulating thermal barrier coatings (TBCs) must be developed to protect the underlying metallic components from higher operating temperatures. This work focused on using rare earth doped (Yb and Gd) yttria stabilized zirconia (t' Low-k) and Gd2Zr2O7 pyrochlores (GZO) combined with novel nanolayered and thick layered microstructures to enable operation beyond the 1200 C stability limit of current 7 wt% yttria stabilized zirconia (7YSZ) coatings. It was observed that the layered system can reduce the thermal conductivity by approximately 45 percent with respect to YSZ after 20 hr of testing at 1316 C. The erosion rate of GZO is shown to be an order to magnitude higher than YSZ and t' Low-k, but this can be reduced by almost 57 percent when utilizing a nanolayered structure. Lastly, the thermal instability of the layered system is investigated and thought is given to optimization of layer thickness.

  4. 废旧氢镍电池负极材料中稀土的资源化利用%The utilization of rare earth from waste hydrogen-nickel battery cathode materials



    A hydrometallurgical flow is designed to recover rare earth, nickel and cobalt from the anode of hydrogen-nickel battery. The recovery procedure includes: anode leaching with sulfuric acid; rare earth sepa-ration in the form of rare earth sulfate from nickel and cobalt; rare earth sulphate neutralization; rare earth, Zn2+and Mn2+separation in the lixivium from nickel and cobalt by using P507 (2-ethylhexyl dihydrogen phos-phate)and kerosene as extractant; stripping rare earth with HCl. The stripping solution is neutralized by rare earth hydroxide resulting the rare earth chloride. The total recovery ratios of rare earth, nickel and cobalt are 98.4%and 98.5%respectively.%设计了综合回收氢镍电池负极材料中稀土元素并同时回收镍、钴的湿法冶金流程.该流程回收的主要步骤包括:硫酸浸出负极,使大部分稀土以硫酸稀土的形式与镍、钴分离,硫酸稀土经碱转化为氢氧化稀土;进入浸出液的稀土,用P507+煤油萃取使其与镍、钴分离,并同时将锌、锰等杂质与镍、钴分离;用HCl反萃稀土,反萃液与氢氧化稀土中和得到氯化稀土.稀土的综合回收率为98.4%,镍、钴的综合回收率为98.5%.

  5. Monolithic Rare Earth Doped PTR Glass Laser Project

    National Aeronautics and Space Administration — The main goal of the project is to demonstrate the feasibility of a monolithic solid state laser on the basis of PTR glass co-doped with luminescent rare earth ions....

  6. Prospects for trivalent rare earth molecular vapor lasers for fusion

    Krupke, W.F.


    The dynamical properties of three types of RE/sup 3 +/ molecular vapors were considered: (1) rare earth trihalogens, (2) rare earth trihalogens complexed with transition metal trihalogens, and (3) rare earth chelates. Radiative and nonradiative (unimolecular and bimolecular) transition probabilities have been calculated using phenomenological models predicted on the unique electronic structure of the triply ionized RE ion (well shielded ground electronic configuration of equivalent of electrons). Although all the lanthanide ions have been treated in some detail, specific results are presented for the Nd/sup 3 +/ and Tb/sup 3 +/ ions to illustrate the systematics of these vapors as a class of new laser media. Once verified, these phenomenological models will provide a powerful tool for the directed experimental exploration of these systems. Because of the structural similarity to the triply ionized actinides, comments offered here for the lanthanide rare earth series generally apply to gaseous actinide lasers which are also under consideration.

  7. Synthesis of Polyketone STCO Promoted by Rare Earth Catalyst

    GUO Jintang; ZHENG Yonghui; WANG Bo; TIAN Jing


    To lower the cost of polyketone synthesis, rare earth coordinate catalyst was introduced to the copolymerization of carbon monoxide (CO) and styrene (ST) to synthesize aliphatic polyketone STCO.The catalytic system was composed of rare earth neodymium acetate, yttrium acetate,2,2'-bipyridine, p-toluensulfonic acid, cupric p-toluensulfonate, and 1,4-benzoquinone.The catalyst and the copolymer were characterized by infrared spectrum and X-ray photoelectron spectroscopy respectively.The effects of each component of catalytic system and the kinds of rare earth acetates on catalytic activity of copolymerization were investigated.The results show that the proposed rare earth has distinct catalytic activity in the copolymerization of CO and ST and the maximum activity can reach 303.3 gSTCO/(mol·h).

  8. Rare Earth Market Review August 20-31


    @@ Rare earth market still went downward affected by continuous price fall of didymium oxide and didymium mischmetal. However, the market of europium oxide (99.99%) remained stable, with price rose slightly.

  9. Rare Earth Doped Optical Fibre From Oxide Nanoparticles

    Minati Chatterjee; Aharon Gedanken; Renata Reisfeld; Ranjan Sen; Mrinmay Pal; Milan Naskar; Mukul Paul; Shyamal Bhadra; Kamal Dasgupta; Dibyendu Ganguli; Tarun Bandyopadhyay


    Rare earth (RE) doped optical fibres were fabricated by using RE oxides coated silica nanoparticles. The fibre properties are comparable to those prepared by conventional techniques. The process offers better control over RE incorporation and homogeneity in the preform.

  10. China vows equal treatment in rare earth regulation


    BEIJING, July 15 (Xinhua)-- China pledged it will abide by World Trade Organization rules and apply "same policies" to both domestic and overseas companies in rare earth production, processing and export.

  11. Rare Earth Doped Silica Nanoparticles via Thermolysis of a Single Source Metallasilsesquioxane Precursor

    Davies, Gemma-Louise; O'Brien, John; Gun'Ko, Yurii K.


    Rare earth metal doped silica nanoparticles have significant advantages over traditional organic dyes and quantum dots. Silsesquioxanes are promising precursors in the production of silica nanoparticles by thermolysis, due to their structural similarities with silica materials. This manuscript describes the production of a new Eu3+-based metallasilsesquioxane species and its use as a single source precursor in the thermolytic production of luminescent rare earth metal doped silica nanoparticles with characteristic emission in the visible region of the spectrum.

  12. Magneto-structural correlations in rare-earth cobalt pnictides

    Thompson, Corey Mitchell

    Magnetic materials are used in many applications such as credit cards, hard drives, electric motors, sensors, etc. Although a vast range of magnetic solids is available for these purposes, our ability to improve their efficiency and discover new materials remains paramount to the sustainable progress and economic profitability in many technological areas. The search for magnetic solids with improved performance requires fundamental understanding of correlations between the structural, electronic, and magnetic properties of existing materials, as well as active exploratory synthesis that targets the development of new magnets. Some of the strongest permanent magnets, Nd 2Fe14B, SmCo5, and Sm2Co17, combine transition and rare-earth metals, benefiting from the strong exchange between the 4f and 3d magnetic sublattices. Although these materials have been studied in great detail, the development of novel magnets requires thorough investigation of other 3d-4 f intermetallics, in order to gain further insights into correlations between their crystal structures and magnetic properties. Among many types of intermetallic materials, ternary pnictides RCo 2Pn2 (R = La, Ce, Pr, Nd; Pn = P, As) are of interest because, despite their simple crystal structures, they contain two magnetic sublattices, exchange interactions between which may lead to rich and unprecedented magnetic behavior. Nevertheless, magnetism of these materials was studied only to a limited extent, especially as compared to the extensive studies of their silicide and germanide analogues. The ThCr2Si2 structure type, to which these ternary pnictides belong, is one of the most ubiquitous atomic arrangements encountered among intermetallic compounds. It accounts for over 1000 known intermetallics and has received increased attention due to the recently discovered FeAs-based superconductors. This dissertation is devoted to the investigation of magnetostructural relationships and anomalous magnetic behaviors in rare

  13. Rare-earth loaded liquid scintillator (for LENS experiment)

    Barabanov, I R; Kornoukhov, V N; Yanovich, E A; Zatsepin, G T; Danilov, N A; Korpusov, G V; Kostukova, G V; Krylov, Y S; Yakshin, V V


    Rare-earth (Yb/Gd) complexes with neutral organophosphorus ligands are briefly discussed for their application in liquid scintillation technique. To evaluate the principal feasibility of rare-earth loaded scintillator, the ytterbium chloride complexes with tri-isoamylphosphine oxides were synthesized. Relative scintillation efficiency (RSE) for two Yb concentrations (78 and 88 g/L) was measured by means of the internal conversion exitation from Cs-137. The results obtained were 50 and 40% respectively.

  14. Hydrogen solubility in rare earth based hydrogen storage alloys

    Uchida, Hirohisa [Tokai Univ., Kanagawa (Japan). School of Engineering; Kuji, Toshiro [Mitsui Mining and Smelting Co. Ltd., Saitama (Japan)


    This paper reviews significant results of recent studies on the hydrogen storage properties of rare earth based AB{sub 5} (A: rare earth element, B: transition element) alloys The hydrogen solubility and the hydride formation, typically appeared in pressure-composition isotherms (PCT), are strongly dependent upon alloy composition, structure, morphology and even alloy particle size. Typical experimental results are shown to describe how these factors affect the hydrogen solubility and storage properties.

  15. Determination of rare earth elements in plant protoplasts by MAA


    A preliminary study on the speciation of rare earth elements in plant cells has been carried out by molecular activation analysis (MAA). Mesophyll protoplasts of Brassica napus were isolated by enzymatic digestion. After being washed with isosmotic solution containing EDTA for several times, the protoplasts were purified by gradient centrifugation. Then the concentration of rare earth elements (REEs) in the protoplasts was determined by neutron activation analysis. The result shows that REEs can enter the cells of the plant.

  16. Ferroelectricity of domain walls in rare earth iron garnet films.

    Popov, A I; Zvezdin, K A; Gareeva, Z V; Mazhitova, F A; Vakhitov, R M; Yumaguzin, A R; Zvezdin, A K


    In this paper, we report on electric polarization arising in a vicinity of Bloch-like domain walls in rare-earth iron garnet films. The domain walls generate an intrinsic magnetic field that breaks an antiferroelectric structure formed in the garnets due to an exchange interaction between rare earth and iron sublattices. We explore 180° domain walls whose formation is energetically preferable in the films with perpendicular magnetic anisotropy. Magnetic and electric structures of the 180° quasi-Bloch domain walls have been simulated at various relations between system parameters. Singlet, doublet ground states of rare earth ions and strongly anisotropic rare earth Ising ions have been considered. Our results show that electric polarization appears in rare earth garnet films at Bloch domain walls, and the maximum of magnetic inhomogeneity is not always linked to the maximum of electric polarization. A number of factors including the temperature, the state of the rare earth ion and the type of a wall influence magnetically induced electric polarization. We show that the value of polarization can be enhanced by the shrinking of the Bloch domain wall width, decreasing the temperature, and increasing the deviations of magnetization from the Bloch rotation that are regulated by impacts given by magnetic anisotropies of the films.

  17. Ferroelectricity of domain walls in rare earth iron garnet films

    Popov, A. I.; Zvezdin, K. A.; Gareeva, Z. V.; Mazhitova, F. A.; Vakhitov, R. M.; Yumaguzin, A. R.; Zvezdin, A. K.


    In this paper, we report on electric polarization arising in a vicinity of Bloch-like domain walls in rare-earth iron garnet films. The domain walls generate an intrinsic magnetic field that breaks an antiferroelectric structure formed in the garnets due to an exchange interaction between rare earth and iron sublattices. We explore 180° domain walls whose formation is energetically preferable in the films with perpendicular magnetic anisotropy. Magnetic and electric structures of the 180° quasi-Bloch domain walls have been simulated at various relations between system parameters. Singlet, doublet ground states of rare earth ions and strongly anisotropic rare earth Ising ions have been considered. Our results show that electric polarization appears in rare earth garnet films at Bloch domain walls, and the maximum of magnetic inhomogeneity is not always linked to the maximum of electric polarization. A number of factors including the temperature, the state of the rare earth ion and the type of a wall influence magnetically induced electric polarization. We show that the value of polarization can be enhanced by the shrinking of the Bloch domain wall width, decreasing the temperature, and increasing the deviations of magnetization from the Bloch rotation that are regulated by impacts given by magnetic anisotropies of the films.

  18. Reverse engineering nuclear properties from rare earth abundances in the r process

    Mumpower, M. R.; McLaughlin, G. C.; Surman, R.; Steiner, A. W.


    The bulk of the rare earth elements are believed to be synthesized in the rapid neutron capture process or r process of nucleosynthesis. The solar r-process residuals show a small peak in the rare earths around A∼ 160, which is proposed to be formed dynamically during the end phase of the r process by a pileup of material. This abundance feature is of particular importance as it is sensitive to both the nuclear physics inputs and the astrophysical conditions of the main r process. We explore the formation of the rare earth peak from the perspective of an inverse problem, using Monte Carlo studies of nuclear masses to investigate the unknown nuclear properties required to best match rare earth abundance sector of the solar isotopic residuals. When nuclear masses are changed, we recalculate the relevant β-decay properties and neutron capture rates in the rare earth region. The feedback provided by this observational constraint allows for the reverse engineering of nuclear properties far from stability where no experimental information exists. We investigate a range of astrophysical conditions with this method and show how these lead to different predictions in the nuclear properties influential to the formation of the rare earth peak. We conclude that targeted experimental campaigns in this region will help to resolve the type of conditions responsible for the production of the rare earth nuclei, and will provide new insights into the longstanding problem of the astrophysical site(s) of the r process.

  19. An introduction to the economics of rare earths

    Bartekova, E.


    The aim of this paper is to examine the supply risk of rare earths and its impact on low carbon technologies deployment. Bringing together seemingly disconnected strands of scientific literature, this multidisciplinary approach allows to provide an overarching overview of the economics of rare

  20. Radioluminescence of rare-earth doped aluminum oxide

    Santiago, M.; Molina, P. [Universidad Nacional del Centro de la Provincia de Buenos Aires, Instituto de Fisica Arroyo Seco, Pinto 399, 7000 Tandil (Argentina); Barros, V. S.; Khoury, H. J.; Elihimas, D. R., E-mail: [Universidade Federal de Pernambuco, Departamento de Energia Nuclear, Av. Prof. Luiz Freire 1000, Recife, PE 50740-540 (Brazil)


    Carbon-doped aluminum oxide (Al{sub 2}O{sub 3}:C) is one of the most used radioluminescence (Rl) materials for fiberoptic dosimetry due to its high efficiency and commercial availability. However, this compound presents the drawback of emitting in the spectral region, where the spurious radioluminescence of fibers is also important. In this work, the radioluminescence response of rare-earth doped Al{sub 2}O{sub 3} samples has been evaluated. The samples were prepared by mixing stoichiometric amounts of aluminum nitrate, urea and dopants with different amounts of terbium, samarium, cerium and thulium nitrates varying from 0 to 0.15 mo 1%. The influence of the different activators on the Rl spectra has been investigated in order to determine the feasibility of using these compounds for Rl fiberoptic dosimetry. (Author)

  1. Clean separation technologies of rare earth resources in China

    LIAO Chunsheng; WU Sheng; CHENG Fuxiang; WANG Songling; LIU Yan; ZHANG Bo; YAN Chunhua


    After a review on the conventional separation process of rare earths (RE),hyperlink extraction technology was introduced and a potential process was proposed for clean separation of RE.A great amount of acid,base and water was consumed in the conventional RE separation process which included the procedures of raw material dissolving,extraction separation and precipitation.Therefore hyperlink extraction technology had been developed,by which the repeated consumption of acid and base could be avoided during the extraction process.And based on the theory and successful applications of the hyperlink extraction technology,we proposed the integral hyperlink process in which the intermediate acid resulted in individual procedures would be recycled and reused after being treated.The proposed process would make it feasible to consume no chemicals except for oxalic acid,and so could be a promising clean separation technology with a significant reduction on consumption and emission.

  2. Rapidly solidified Mg-Al-Zn-rare earth alloys

    Chang, C.F.; Das, S.K.; Raybould, D.


    Among the light metal alloys, magnesium is the lightest structural material except for beryllium, and yet magnesium alloys have not seen extensive use because of their poor strength and corrosion resistance. Rapid solidification technology offers a possible solution to these problems. A number of Mg-Al-Zn alloys containing rare earth (RE) elements (e.g. Ce, Pr, Y, and Nd) have been investigated using rapid solidification processing for possible structural applications. The processing consists of planar flow or jet casting into ribbons, pulverization of ribbon to powder, and consolidation of powder into bulk shapes. The mechanical properties of some of these alloys show attractive combinations of strength, ductility and corrosion resistance. The microstructures of these alloys are correlated with their mechanical properties. The rapidly solidified Mg-Al-Zn-RE alloys show great potential for applications in automotive and aerospace industries. 7 references.

  3. Synthesis and characterization of hydrogel bonded with rare earth

    YAN Changhao; JIAO Lianlian; GUO Chunfang; ZHANG Ming; QIU Guanming


    Chitosan-poly(acrylic acid) hydrogel bonded with Eu3+ was prepared by radical solution polymerization. Biodegradable chitosan,N,N'-methylen-diacrylamide, and potassium persulphate were used as the basic material, cross-linking agent, and initiator, respectively. The structure and thermal property of hydrogel were characterized by infrared spectrometry, X-ray diffraction, scanning electron microscopy, and differential scanning calorimetry. The swollen property and fluorescent performance were also characterized. The results showed that the rare earth presented unique distribution in the hydrogel due to the formation of chemical bonds after polymerization. The glass transition tem-perature of the hydrogel decreased remarkably, which might broaden the range of its elastic application considerably. Moreover, the charac-teristic fluorescent emission of Eu3+ was observed in the hydrogel, which was indicative of the excellent luminescent performance.

  4. Structural and mechanical stability of rare-earth diborides

    Haci Ozisik; Engin Deligoz; Kemal Colakoglu; Gokhan Surucu


    Structural and mechanical properties of several rare-earth diborides were systematically investigated by first principles calculations.Specifically,we studied XB2,where X =Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,and Lu in the hexagonal A1B2,ReB2,and orthorhombic OsB2-type structures.The lattice parameters,bulk modulus,bond distances,second order elastic constants,and related polycrystalline elastic moduli (e.g.,shear modulus,Young's modulus,Poisson's ratio,Debye temperature,sound velocities) were calculated.Our results indicate that these compounds are mechanically stable in the considered structures,and according to "Chen's method",the predicted Vickers hardness shows that they are hard materials in A1B2-and OsB2-type structures.

  5. Effect of Annealing on Rare Earth Based Hydrogen Storage Alloys

    Li Jinhua


    Rare earth-based hydrogen storage alloy used as negative electrode materials for nickel-metal hydride (Ni-MH) batteries are used commercially.The effect of annealing treatment with different annealing temperature and time on the MLNi3.68 Co0.78 Mn0.35 Al0.27 and MMNi3.55 Co0.75 Mn0.40 Al0.30 alloys were investigated.The crystal microstructure,pressure-composition-isotherms (p-C-T) and electrochemical properties of alloys were examined by X-ray diffraction (XRD), automatic PCI monitoring system and electrical performance testing instruments.The optimum annealing treatment conditions of two kinds of alloys were determined.

  6. Commercial Reserve will Help Rare Earth Industry to Leave Behind Cold Winter


    As key component in the construction of rare earth strategy reserve system,the rare earth commercial reserve,an initiative advocated by the state government,spontaneously carried out by several major rare earth enterprise groups to target at reform of the supply front for the rare earth industry,formally kicked off.The encouraging news is that,within a matter of one month,affected by news of rare earth commercial reserve,rare earth market prices

  7. Protecting the environment and public health from rare earth mining

    Huang, Xiang; Zhang, Guochun; Pan, An; Chen, Fengying; Zheng, Chunli


    As increasing demand for green energy and high-tech devices grows, so does the rising prospecting of rare earth metals required for their production. Protecting the environment and public health from rare earth element (REE) mining as well as emerging pollutants is urgently required to achieve sustainable development. This study mapped Earth's hidden REE deposits to identify potential contamination hotspots with the aim of preventing its deleterious effects on the environment. We worry that there would be widespread tailing facilities concomitant with serious pollutions, such as the Bayan Obo tailings site, and argue that a tradeoff between the underground REE exploration and environment conservation should be reached as soon as possible.

  8. Instability of some divalent rare earth ions and photochromic effect

    Egranov, A. V.; Sizova, T. Yu.; Shendrik, R. Yu.; Smirnova, N. A.


    It was shown that the divalent rare earth ions (La, Ce, Gd, Tb, Lu, and Y) in cubic sites in alkaline earth fluorides are unstable with respect to electron autodetachment since its d1(eg) ground state is located in the conduction band which is consistent with the general tendency of these ions in various compounds. The localization of doubly degenerate d1(eg) level in the conduction band creates a configuration instability around the divalent rare earth ion that leading to the formation of an...

  9. Prospective analysis of the flows of certain rare earths in Europe at the 2020 horizon.

    Rollat, Alain; Guyonnet, Dominique; Planchon, Mariane; Tuduri, Johann


    This paper proposes a forecast of certain rare earth flows in Europe at the 2020 horizon, based on an analysis of trends influencing various actors of the rare earth industry along the value chain. While 2020 is indicated as the forecast horizon, the analysis should be considered as more representative of the next decade. The rare earths considered here are used in applications that are important for a low-carbon energy transition and/or have a significant recycling potential: NdFeB magnets (Pr, Nd, Dy), NiMH batteries (Pr, Nd) and fluorescent lamp phosphors (Eu, Tb, Y). An analysis of major trends affecting the rare earth industry in Europe along the value chain (including extraction, separation, fabrication, manufacture, use and recycling), helps to build a scenario for a material flow analysis of these rare earths in Europe. The scenario assumes in particular that during the next decade, there exists a rare earth mine in production in Europe (with Norra Kärr in Sweden as a most likely candidate) and also that recycling is in line with targets proposed in recent European legislation. Results are presented in the form of Sankey diagrams which help visualize the various flows for the three applications. For example, calculations forecast flows from extraction to separation of Pr, Nd and Dy for magnet applications in Europe, on the order of 310 tons, 980 tons and 80 tons rare earth metal resp., while recycled flows are 35 tons, 110 tons and 30 tons resp. Calculations illustrate how the relative contribution of recycling to supply strongly depends on the situation with respect to demand. Considering the balance between supply and demand, it is not anticipated any significant shortage of rare earth supply in Europe at the 2020 horizon, barring any new geopolitical crisis involving China. For some heavy rare earths, supply will in fact largely outweigh demand, as for example Europium due to the phasing out of fluorescent lights by LEDs.

  10. Dynamics of dipolar defects in rare earth-doped alkaline-earth fluoride crystals

    Charnock, Forrest Taylor

    Alkaline-earth fluoride crystals such as SrF2 provide an excellent sample material for investigating the physics of point defects in crystal lattices. High quality crystals are easily grown, and they readily accept many dopant ions into the lattice, particularly rare earth ions. Rare earth dopant ions (typically trivalent) occupy substitutional sites in the lattice by replacing a Sr2+ ion. Due to the extra charge of the rare earth ion, charge compensation is often provided by an extra fluoride ion (F--) located in a nearby interstitial position. If located in the nearest-neighbor (nn) interstitial position, it forms a defect with C4n symmetry; if located in the next-nearest-neighbor (nnn) intersitial position, it forms a defect with C3n symmetry. Given sufficient thermal energy, this interstitial F ion can move to adjacent interstitial sites and hence reorient the defect. The rate w at which the ion moves from one interstitial site to another is well described by a simple Arrhenius expression: w=n0e-E/kT , where n0 is the attack frequency of the F-- and E is the activation energy. This motion can profoundly affect both the electronic polarizability of the material and the polarization of light emitted or absorbed by the rare earth ion. This thesis describes the normal mode motion of interstitial ions which may occupy either nn or nnn interstitial sites. Using electron paramagnetic resonance (EPR), I observed the relative populations of nn and nnn defects in SrF2 doped with Gd3+ as a function of temperature. These measurements show that dipolar reorientation of the nnn F occurs through the nn interstitial position. Not all interstitial F-- motion is thermally driven. Fluorescence depolarization measurements of SrF2:Pr3+ indicate that optically stimulating a Pr3+ may induce interstitial motion of a nn F--. Such motion was confirmed by showing that nn defects in SrF2:Pr3+ may be polarized at very low temperatures when the sample is illuminated with resonant light. I

  11. Mining and Exploitation of Rare Earth Elements in Africa as an Engagement Strategy in US Africa Command


    extraction difficult and costly, since they pose the risk of radiation leaks.”8 “In the few cases in which the rare-earth ion can be oxidized or... solvents are then applied to the bastnaesite to separate out the rare earths. Once separated, they are reprocessed to increase the purity level...material was the rare earth element flourocarbonate bastnaesite.29 The discouraged miners moved on. The Molybdenum Corporation laid claim to the

  12. Rare Earth Elements - A New Challenge for the World Economy

    Cristina Bumbac


    Full Text Available Rare Earth Elements or Rare Earth Metals (REM are a collection of seventeen chemical elements in the periodic table, namely scandium, yttrium and fifteen lanthanides. The term "rare earth" arises from the rare earth minerals from which they were first isolated. They are uncommon oxide-type minerals (earths found in Gandolinite extracted from one mine in Sweden. The first discovery was made in 1794, but it was only in 1940 that the scientist Frank Spedding developed an ion exchange procedure for separating and purifying the REM. For the next decades, they were hardly used in some "minor" industrial fields. Only after 2000 their importance grew, once the multitude of possibilities to use them was discovered due to technological progress. Now REM are incorporated into almost all modern technological devices: superconductors, magnets, electronic polishers, refining catalysts hybrid car components and military techniques. They are used in small quantities, but due to their extraordinary properties the prices are very high. The main problem is that China dominates this market, with 97% of total global supply. The highest concentration of rare earth metals are in Inner Mongolia in China, Mountain Pass in California U.S.A. and in Mount Weld in Australia. The developed countries are far behind China regarding production and are indeed depending on Chinese exports. Hence, there is a difficult situation on this particular market, with an uncertain future.

  13. Contributed Review: A review of the investigation of rare-earth dopant profiles in optical fibers

    Sidiroglou, F.; Baxter, G. [Optical Technology Research Laboratory, College of Engineering and Science, Victoria University, P.O. Box 14428, Melbourne, VIC 8001 (Australia); Roberts, A. [School of Physics, The University of Melbourne, Melbourne, VIC 3010 (Australia)


    Rare-earth doped optical fibers have captivated the interest of many researchers around the world across the past three decades. The growth of this research field has been stimulated primarily through their application in optical communications as fiber lasers and amplifiers, although rare-earth doped optical fiber based devices are now finding important uses in many other scientific and industrial areas (for example, medicine, sensing, the military, and material processing). Such wide commercial interest has provided a strong incentive for innovative fiber designs, alternative glass compositions, and novel fabrication processes. A prerequisite for the ongoing progress of this research field is developing the capacity to provide high resolution information about the rare-earth dopant distribution profiles within the optical fibers. This paper constitutes a comprehensive review of the imaging techniques that have been utilized in the analysis of the distribution of the rare-earth ion erbium within the core of optical fibers.

  14. Contributed Review: A review of the investigation of rare-earth dopant profiles in optical fibers

    Sidiroglou, F.; Roberts, A.; Baxter, G.


    Rare-earth doped optical fibers have captivated the interest of many researchers around the world across the past three decades. The growth of this research field has been stimulated primarily through their application in optical communications as fiber lasers and amplifiers, although rare-earth doped optical fiber based devices are now finding important uses in many other scientific and industrial areas (for example, medicine, sensing, the military, and material processing). Such wide commercial interest has provided a strong incentive for innovative fiber designs, alternative glass compositions, and novel fabrication processes. A prerequisite for the ongoing progress of this research field is developing the capacity to provide high resolution information about the rare-earth dopant distribution profiles within the optical fibers. This paper constitutes a comprehensive review of the imaging techniques that have been utilized in the analysis of the distribution of the rare-earth ion erbium within the core of optical fibers.

  15. Complex rare-earth aluminum hydrides: mechanochemical preparation, crystal structure and potential for hydrogen storage.

    Weidenthaler, Claudia; Pommerin, André; Felderhoff, Michael; Sun, Wenhao; Wolverton, Christopher; Bogdanović, Borislav; Schüth, Ferdi


    A novel type of complex rare-earth aluminum hydride was prepared by mechanochemical preparation. The crystal structure of the REAlH(6) (with RE = La, Ce, Pr, Nd) compounds was calculated by DFT methods and confirmed by preliminary structure refinements. The trigonal crystal structure consists of isolated [AlH(6)](3-) octahedra bridged via [12] coordinated RE cations. The investigation of the rare-earth aluminum hydrides during thermolysis shows a decrease of thermal stability with increasing atomic number of the RE element. Rare-earth hydrides (REH(x)) are formed as primary dehydrogenation products; the final products are RE-aluminum alloys. The calculated decomposition enthalpies of the rare-earth aluminum hydrides are at the lower end for reversible hydrogenation under moderate conditions. Even though these materials may require somewhat higher pressures and/or lower temperatures for rehydrogenation, they are interesting examples of low-temperature metal hydrides for which reversibility might be reached.

  16. Study on Preparation and Property of Poly-Aminosilicone-Rare Earth Composite

    Zhang Ming(张明); Qiu Guanming(邱关明); Chen Haiyan(陈海燕); Zhou Lanxiang(周兰香); Inoue Shinich; Okamoto Hiroshi


    The poly-aminosilicone-rare earth composite was prepared by poly-aminosilicone cross-linked with rare earth and active silanol. The thermal stability of the composites was studied by thermogravimetric analysis (TG). Force condition of the composites in electric field was analyzed and relative polarizability was derived. It is found that the composites containing different rare earth ions have different relative polarizability. The experiment results reveal that organosilicon materials with different electrical performance can be obtained by this way. Meanwhile, the absorption and flourescene spectrum of composites were also investigated. Compared to rare earth chloride, the spectrum properties of the composite are changed obviously. The possible reasons for these phenomena were discussed.

  17. Addressing Rare-Earth Element Criticality: An Example from the Aviation Industry

    Ku, Anthony Y.; Dosch, Christopher; Grossman, Theodore R.; Herzog, Joseph L.; Maricocchi, Antonio F.; Polli, Drew; Lipkin, Don M.


    Rare-earth (RE) elements are enablers for a wide range of technologies, including high-strength permanent magnets, energy-efficient lighting, high-temperature thermal barrier coatings, and catalysts. While direct material substitution is difficult in many of these applications because of the specific electronic, optical, or electrochemical properties imparted by the individual rare-earth elements, we describe an example from the aviation industry where supply chain optimization may be an option. Ceramic matrix composite engine components require environmental barrier coatings (EBCs) to protect them from extreme temperatures and adverse reactions with water vapor in the hot gas path. EBC systems based on rare-earth silicates offer a unique combination of environmental resistance, thermal expansion matching, thermal conductivity, and thermal stability across the service temperature window. Several pure rare-earth silicates and solid solutions have been demonstrated in EBC applications. However, all rely on heavy rare-earth elements (HREEs) for phase stability. This article considers the possibility of using separation tailings containing a mixture of HREEs as a source material in lieu of using the high-purity HREE oxides. This option arises because the desired properties of RE-silicate EBCs derive from the average cation size rather than the electronic properties of the individual rare-earth cations. Because separation tailings have not incurred the costs associated with the final stages of separation, they offer an economical alternative to high-purity oxides for this emerging application.

  18. Status of Rare Earths for Agriculture in China

    Wang Jiachen; Yang Jun; Liu Xiangsheng


    Rare Earths (RE) for agriculture is a very typical application and has already brought good economic benefit to Chinese agriculture and farmers.In this paper, the origin, development, status and the future of RE for agriculture in China were discussed.Firstly, through the researches of RE in the fields of physiological activity, physiological and biochemical mechanism, sanitation toxicology and environment security in 1980's, RE has been extended more widely in agriculture, such as crops, vegetables, forest, wood grass and stock breeding, such as cattle, fish and chicken.Secondly, with using of new techniques that were developed in the "State Ninth Five-Year Plan", the utilization area of RE was expanded to broad agricultural space, such as sunlight converting plastic film, RE fertilizer, RE drought resistant and RE water saving materials and new RE top dressing fertilizer.Thirdly, with the development of the nanometer materials, the techniques and process of nanometer RE materials were focused.Around these kinds of materials, the new seed cover matters, new seed mixed matter and new nanometer fertilizer will appear in the near future, and will produce many updated techniques and improve a new round RE application in agriculture.

  19. Rb-Sr age and content of potassium, rubidium strontium, barium, and rare earths in surface material from the Sea of Fertility

    Allegre, C. J.; Birck, J. L.; Loubet, M.; Provost, A.


    The Luna 16 automatic station returned from the Sea of Fertility a 35 cm long column of lunar surface material. 1 g of the Luna 16 lunar surface material, taken at a depth of 22 cm, consists of fine material: surface material and fine fragments of rocks from 1 to 4 mm in diameter. Analyses made on 17 mg of the fine lunar surface material are presented. The results obtained for the Luna 16 surface material are plotted on the diagram of the isotopic evolution of strontium and show that this surface material is most depleted of radiogenic Sr-87 of all the known lunar surface materials and that the point characterizing Lunar 16 lies somewhat to the right of the line corresponding to an age of 4.6 billion years.

  20. Instability of some divalent rare earth ions and photochromic effect

    Egranov, A. V.; Sizova, T. Yu.; Shendrik, R. Yu.; Smirnova, N. A.


    It was shown that the divalent rare earth ions (La, Ce, Gd, Tb, Lu, and Y) in cubic sites in alkaline earth fluorides are unstable with respect to electron autodetachment since its d1(eg) ground state is located in the conduction band which is consistent with the general tendency of these ions in various compounds. The localization of doubly degenerate d1(eg) level in the conduction band creates a configuration instability around the divalent rare earth ion that leading to the formation of anion vacancy in the nearest neighborhood, as was reported in the previous paper [A. Egranov, T. Sizova, Configurational instability at the excited impurity ions in alkaline earth fluorites, J. Phys. Chem. Solids 74 (2013) 530-534]. Thus, the formation of the stable divalent ions as La, Ce, Gd, Tb, Lu, and Y (PC+ centers) in CaF2 and SrF2 crystals during x-ray irradiation occurs via the formation of charged anion vacancies near divalent ions (Re2+va), which lower the ground state of the divalent ion relative to the conductivity band. Photochromic effect occurs under thermally or optically stimulated electron transition from the divalent rare earth ion to the neighboring anion vacancy and reverse under ultraviolet light irradiation. It is shown that the optical absorption of the PC+ centers due to d → d and d → f transitions of the divalent rare-earth ion.

  1. Técnica de bombeio e prova para medidas de absorção de estado excitado e de emissão estimulada, em materiais sólidos dopados com íons terras raras Pump-probe technique for excited state absorption and stimulated emission measurements in rare earth ion doped solid materials

    Andrea Simone Stucchi de Camargo


    Full Text Available Rare earth ion doped solid state materials are the most important active media of near-infrared and visible lasers and other photonic devices. In these ions, the occurrence of Excited State Absorptions (ESA, from long lived electronic levels, is commonplace. Since ESA can deeply affect the efficiencies of the rare earth emissions, evaluation of these transitions cross sections is of greatest importance in predicting the potential applications of a given material. In this paper a detailed description of the pump-probe technique for ESA measurements is presented, with a review of several examples of applications in Nd3+, Tm3+ and Er3+ doped materials.

  2. Method for treating rare earth-transition metal scrap

    Schmidt, Frederick A.; Peterson, David T.; Wheelock, John T.; Jones, Lawrence L.


    Rare earth-transition metal (e.g., iron) scrap (e.g., Nd-Fe-B scrap) is flux (slag) remelted to reduce tramp non-metallic impurities, such as oxygen and nitrogen, and metallic impurities, such as Li, Na, Al, etc., picked up by the scrap from previous fabrication operations. The tramp impurities are reduced to concentrations acceptable for reuse of the treated alloy in the manufacture of end-use articles, such as permanent magnets. The scrap is electroslag or inductoslag melted using a prefused, rare earth fluoride-bearing flux of CaF.sub.2, CaCl.sub.2 or mixtures thereof or the slag resulting from practice of the thermite reduction process to make a rare earth-iron alloy.

  3. Examination of Plasma Nitriding Microstructure with Addition of Rare Earths



    Medium-carbon alloy steel was plasma nitrided with rare earths La,Ce and Nd into the nitriding chamber respectively.The nitriding layer microstructures with and without rare earths were compared using optical microscope,normal SEM and high resolution SEM,as well as TEM.It was found that the extent of the influence on plasma nitriding varies with different contents of rare earth.The effect of plasma nitriding is benefit from adding of Ce or Nd.The formation of hard and brittle phase Fe2-3N can be prevented and the butterfly-like structure can be improved by adding Ce or Nd.However,pure La may prevent the diffusion of nitrogen and the formation of iron nitride,and reduce the depth of diffusion layer.

  4. Thermal shock behavior of rare earth modified alumina ceramic composites

    Sun, Junlong; Liu, Changxia [Ludong Univ., Yantai (China). School of Transportation


    Alumina matrix ceramic composites toughened by AlTiC master alloys, diopside and rare earths were fabricated by hot-pressing and their thermal shock behavior was investigated and compared with that of monolithic alumina. Results showed that the critical thermal shock temperature (ΔT) of monolithic alumina was 400 C. However, it decreased to 300 C for alumina incorporating only AlTiC master alloys, and increased with further addition of diopside and rare earths. Improvement of thermal shock resistance was obtained for alumina ceramic composites containing 9.5 wt.% AlTiC master alloys and 0.5 wt.% rare earth additions, which was mainly attributed to the formation of elongated grains in the composites.

  5. Refining and Mutual Separation of Rare Earths Using Biomass Wastes

    Inoue, Katsutoshi; Alam, Shafiq


    Two different types of adsorption gels were prepared from biomass wastes. The first gel was produced from astringent persimmon peel rich in persimmon tannin, a polyphenol compound, which was prepared by means of simple dehydration condensation reaction using concentrated sulfuric acid for crosslinking. This adsorption gel was intended to be employed for the removal of radioactive elements, uranium (U(VI)) and thorium (Th(IV)), from rare earths. The second gel was prepared from chitosan, a basic polysaccharide, produced from shells of crustaceans such as crabs, shrimps, prawns, and other biomass wastes generated in marine product industry, by immobilizing functional groups of complexanes such as ethylendiaminetetraacetic acid and diethylentriaminepentaacetic acid (DTPA). This gel was developed for the mutual separation of rare earths. Of the two adsorption gels evaluated, the DTPA immobilized chitosan exhibited the most effective mutual separation among light rare earths.

  6. Optical Frequency Comb Spectroscopy of Rare Earth Atoms

    Swiatlowski, Jerlyn; Palm, Christopher; Joshi, Trinity; Montcrieffe, Caitlin; Jackson Kimball, Derek


    We discuss progress in our experimental program to employ optical-frequency-comb-based spectroscopy to understand the complex spectra of rare-earth atoms. We plan to carry out systematic measurements of atomic transitions in rare-earth atoms to elucidate the energy level structure and term assignment and determine presently unknown atomic state parameters. This spectroscopic information is important in view of the increasing interest in rare-earth atoms for atomic frequency standards, in astrophysical investigations of chemically peculiar stars, and in tests of fundamental physics (tests of parity and time-reversal invariance, searches for time variation of fundamental constants, etc.). We are presently studying the use of hollow cathode lamps as atomic sources for two-photon frequency comb spectroscopy. Supported by the National Science Foundation under grant PHY-0958749.

  7. Formation of intermetallic compound at interface between rare earth elements and ferritic-martensitic steel by fuel cladding chemical interaction

    Jun Hwan Kim; Byoung Oon Lee; Chan Bock Lee; Seung Hyun Jee; Young Soo Yoon


    The intermetallic compounds formation at interface between rare earth elements and clad material were investigated to demonstrate the effects of rare earth elements on fuel-cladding chemical interaction (FCCI) behavior.Mischmetal (70Ce-30La) and Nd were prepared as rare earth elements.Diffusion couple testing was performed on the rare earth elements and cladding (9Cr2W steel) near the operation temperature of(sodium-cooled fast reactor) SFR fuel.The performance of a diffusion barrier consisting of Zr and V metallic foil against the rare earth elements was also evaluated.Our results showed that Ce and Nd in the rare earth elements and Fe in the clad material interdiffused and reacted to form intermetallic species according to the parabolic rate law,describing the migration of the rare earth element.The diffusion of Fe limited the reaction progress such that the entire process was governed by the cubic rate law.Rare earth materials could be used as a surrogate for high burnup metallic fuels,and the performance of the barrier material was demonstrated to be effective.

  8. China's Rare Earth Supply Chain: Illegal Production, and Response to new Cerium Demand

    Nguyen, Ruby Thuy; Imholte, D. Devin


    As the demand for personal electronic devices, wind turbines, and electric vehicles increases, the world becomes more dependent on rare earth elements. Given the volatile, Chinese-concentrated supply chain, global attempts have been made to diversify supply of these materials. However, the overall effect of supply diversification on the entire supply chain, including increasing low-value rare earth demand, is not fully understood. This paper is the first attempt to shed some light on China's supply chain from both demand and supply perspectives, taking into account different Chinese policies such as mining quotas, separation quotas, export quotas, and resource taxes. We constructed a simulation model using Powersim Studio that analyzes production (both legal and illegal), production costs, Chinese and rest-of-world demand, and market dynamics. We also simulated new demand of an automotive aluminum-cerium alloy in the US market starting from 2018. Results showed that market share of the illegal sector has grown since 2007-2015, ranging between 22% and 25% of China's rare earth supply, translating into 59-65% illegal heavy rare earths and 14-16% illegal light rare earths. There will be a shortage in certain light and heavy rare earths given three production quota scenarios and constant demand growth rate from 2015 to 2030. The new simulated Ce demand would require supply beyond that produced in China. Finally, we illustrate revenue streams for different ore compositions in China in 2015.

  9. Structure of Rare-earth/Alkali Halide Complexes

    Akdeniz, Z.; Önem, Z. Çiçek; Tosia, M. P.


    Vapour complex formation of rare-earth halides with alkali halides strongly increases the volatility of these compounds. We evaluate the structure taken by such complexes having the chemical formulas MRX4, M2RX5 and M3RX6, where X = F or Cl and typically M = Li or Na and R = La. The roles played by the two types of metal atom is investigated in MRX4 complexes by also taking M = K, Rb or Cs and R = Gd or Lu. The main predictions that emerge from our calculations are as follows: (i) in MRX4 a fourfold coordination of the rare-earth atom is accompanied by twofold or threefold coordination of the alkali atom, the energy difference in favour of the twofold-coordination state being about 0.3 eV in the case of the LiF complexing agent but even changing sign as the ionic radius of either the alkali or the halogen is increased; (ii) in M2RX5 a fivefold coordination of the rare-earth atom is energetically more stable than a fourfold one, by again not more than about 0.3 eV; (iii) in M3RX6 the fivefold and sixfold coordinations of the rare-earth atom are energetically competitive; and (iv) in both M2RX5 and M3RX6 each coordination state can be realized in various forms that differ in detail but are close in energy. Bond fluctuations and disorder around the rare-earth atom can be expected to be a general feature at elevated temperatures, both in the vapour and in liquid rare-earth/alkali halide mixtures.

  10. Integrated Automation System for Rare Earth Countercurrent Extraction Process

    柴天佑; 杨辉


    Lower automation level in industrial rare-earth extraction processes results in high production cost, inconsistent product quality and great consumption of resources in China. An integrated automation system for extraction process of rare earth is proposed to realize optimal product indices, such as product purity,recycle rate and output. The optimal control strategy for output component, structure and function of the two-gradcd integrated automation system composed of the process management grade and the process control grade were discussed. This system is successfully applied to a HAB yttrium extraction production process and was found to provide optimal control, optimal operation, optimal management and remarkable benefits.

  11. Imports (&) Exports Review of Chinese Rare Earths (continued)


    @@ Since 2001, China kept its position of the largest producing country of rare earth magnets in the world and worked on further in the global market. China exported 7,709 tons of rare earth magnets and earned foreign currency of US $ 214 million in 2004, increasing 37.2% and 33.0% over the same period of 2003 respectively. In 2005, China exported 8,756 tons of RE magnets and earned foreign currency of US $ 239 million, up 13.9% and 11.4% over 2004 respectively. The first six export destinations are listed in Table 3.

  12. Microwave studies on double rare earth oxalate crystals

    Elizabeth, Anit [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Joseph, Cyriac [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Paul, Issac [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Ittyachen, M.A. [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Mathew, K.T. [Microwave Imaging and Material Research Laboratory, Department of Electronics, Cochin University of Science and Technology, Kochi 682022 (India)]. E-mail:; Lonappan, Anil [Microwave Imaging and Material Research Laboratory, Department of Electronics, Cochin University of Science and Technology, Kochi 682022 (India); Jacob, Joe [Microwave Imaging and Material Research Laboratory, Department of Electronics, Cochin University of Science and Technology, Kochi 682022 (India)


    Rare earth compounds are recognized for outstanding physical, magnetic and optical properties. The oxalates and molybdates have gained importance for their various properties, which find applications in electro and accusto optical devices. This paper reports the microwave dielectric studies on double rare earth oxalate crystals. Using the cavity perturbation technique dielectric parameters such as complex permittivity and conductivity at microwave frequencies is determined. Using X-ray diffraction study the crystalline nature of the samples was established. The molecular and crystal structures were identified by IR analysis.

  13. Announcement of Resolutions at the 15th Meeting of the 3rd Session of the Board of Directors of Baogang Rare Earth(continued)


    @@ 4. Proposal on Production Expansion of Baotou Rewin Rare Earth Metallic Materials Co., Lid To further enlarge production capacity of neodymium (didymium) metal of Baotou Rewin Rare Earth Metallic Materials Co., Ltd, which is a holding company of Baogang Rare Earth (Baogang Rare Earth holds 58.42% of the shares of Rewin), enhance local utilization rate of neodymium (didymium) oxide inside Baogang Rare Earth and ensure raw materials supply for future development of NdFeB magnetic materials of Baogang Rare Earth, Baogang Rare Earth approves the project of "Investment of Rewin in production expansion of 3,000 tons of neodymium (didymium) metal per annum". Production capacity of neodymium (didymium) metal of Rewin will approach 8,000 tons/year.

  14. Trace Level Rare Earth Elements Separation From Gram Scale Uranium by Calcium Fluoride Coprecipitation

    WANG; Xiu-feng


    In the fission yield measurement of rare earth elements of uranium induced by neutron,and the analysis of rare earth elements in spent fuel,the separation of trace rare earth elements from a large number of uranium has very important significance.We separated trace level rare earth elements from gram scale uranium by calcium fluoride coprecipitation in this paper.

  15. Thin-Film Photoluminescent Properties and the Atomistic Model of Mg2TiO4 as a Non-rare Earth Matrix Material for Red-Emitting Phosphor

    Huang, Chieh-Szu; Chang, Ming-Chuan; Huang, Cheng-Liang; Lin, Shih-kang


    Thin-film electroluminescent devices are promising solid-state lighting devices. Red light-emitting phosphor is the key component to be integrated with the well-established blue light-emitting diode chips for stimulating natural sunlight. However, environmentally hazardous rare-earth (RE) dopants, e.g. Eu2+ and Ce2+, are commonly used for red-emitting phosphors. Mg2TiO4 inverse spinel has been reported as a promising matrix material for "RE-free" red light luminescent material. In this paper, Mg2TiO4 inverse spinel is investigated using both experimental and theoretical approaches. The Mg2TiO4 thin films were deposited on Si (100) substrates using either spin-coating with the sol-gel process, or radio frequency sputtering, and annealed at various temperatures ranging from 600°C to 900°C. The crystallinity, microstructures, and photoluminescent properties of the Mg2TiO4 thin films were characterized. In addition, the atomistic model of the Mg2TiO4 inverse spinel was constructed, and the electronic band structure of Mg2TiO4 was calculated based on density functional theory. Essential physical and optoelectronic properties of the Mg2TiO4 luminance material as well as its optimal thin-film processing conditions were comprehensively reported.

  16. Thin-Film Photoluminescent Properties and the Atomistic Model of Mg2TiO4 as a Non-rare Earth Matrix Material for Red-Emitting Phosphor

    Huang, Chieh-Szu; Chang, Ming-Chuan; Huang, Cheng-Liang; Lin, Shih-kang


    Thin-film electroluminescent devices are promising solid-state lighting devices. Red light-emitting phosphor is the key component to be integrated with the well-established blue light-emitting diode chips for stimulating natural sunlight. However, environmentally hazardous rare-earth (RE) dopants, e.g. Eu2+ and Ce2+, are commonly used for red-emitting phosphors. Mg2TiO4 inverse spinel has been reported as a promising matrix material for "RE-free" red light luminescent material. In this paper, Mg2TiO4 inverse spinel is investigated using both experimental and theoretical approaches. The Mg2TiO4 thin films were deposited on Si (100) substrates using either spin-coating with the sol-gel process, or radio frequency sputtering, and annealed at various temperatures ranging from 600°C to 900°C. The crystallinity, microstructures, and photoluminescent properties of the Mg2TiO4 thin films were characterized. In addition, the atomistic model of the Mg2TiO4 inverse spinel was constructed, and the electronic band structure of Mg2TiO4 was calculated based on density functional theory. Essential physical and optoelectronic properties of the Mg2TiO4 luminance material as well as its optimal thin-film processing conditions were comprehensively reported.

  17. Determination of thorium and of rare earth elements in cerium earth minerals and ores

    Carron, M.K.; Skinner, D.L.; Stevens, R.E.


    The conventional oxalate method for precipitating thorium and the rare earth elements in acid solution exhibits definite solubilities of these elements. The present work was undertaken to establish conditions overcoming these solubilities and to find optimum conditions for precipitating thorium and the rare earth elements as hydroxides and sebacates. The investigations resulted in a reliable procedure applicable to samples in which the cerium group elements predominate. The oxalate precipitations are made from homogeneous solution at pH 2 by adding a prepared solution of anhydrous oxalic acid in methanol instead of the more expensive crystalline methyl oxalate. Calcium is added as a carrier. Quantitative precipitation of thorium and the rare earth elements is ascertained by further small additions of calcium to the supernatant liquid, until the added calcium precipitates as oxalate within 2 minutes. Calcium is removed by precipitating the hydroxides of thorium and rare earths at room temperature by adding ammonium hydroxide to pH > 10. Thorium is separated as the sebacate at pH 2.5, and the rare earths are precipitated with ammonium sebacate at pH 9. Maximum errors for combined weights of thorium and rare earth oxides on synthetic mixtures are ??0.6 mg. Maximum error for separated thoria is ??0.5 mg.

  18. Automation System in Rare Earths Countercurrent Extraction Processes

    贾江涛; 严纯华; 廖春生; 吴声; 王明文; 李标国


    Based on the countercurrent extraction theory for optimized designing and simulating, the rare earth separation processes, the selection of the detecting points (stages) and on-line analysis for elements, the simulation of open loop response and its response speed, the diagnosis and the regulative prescription for running the solvent extraction cascades were studied.

  19. Direct Reuse of Rare Earth Permanent Magnets—Coating Integrity

    Høgberg, Stig; Holbøll, Joachim; Mijatovic, Nenad


    Rare earth permanent magnets can be reused directly as an alternative to traditional recycling methods, in which scrapped magnets are reprocessed into new magnets by undergoing many of the original energy-intensive and expensive production processes. Direct reuse entails using segmented magnet...

  20. Systematic hardness measurements on some rare earth garnet crystals

    D B Sirdeshmukh; L Sirdeshmukh; K G Subhadra; K Kishan Rao; S Bal Laxman


    Microhardness measurements were undertaken on twelve rare earth garnet crystals. In yttrium aluminium garnet and gadolinium gallium garnet, there was no measurable difference in the hardness values of pure and nominally Nd-doped crystals. The hardness values were correlated with the lattice and elastic constants. An analysis of hardness data in terms of the interatomic binding indicated a high degree of covalency.

  1. Strategy of Development of Rare Earth Industry in China

    Su Wenqing


    This work introduced the current situation of the development of domestic and foreign rare earths (RE) industry, discussed the strategic position of RE industry in China, analyzed the problems existing in the course of RE industry development, made strategic thought about the transference from resource advantage to economic advantage, and put forward strategic suggestions about the development of RE industry in our country.

  2. Rare earth point defects in GaN

    Sanna, S.


    In this work we investigate rare earth doped GaN, by means of theoretical simulations. The huge unit cells necessary to model the experimental system, where dilute amount of rare earth ions are used, are handled with the charge self consistent density-functional based-tight binding (SCC-DFTB) calculational scheme. The method has been extended to include LDA+U and simplified self interaction corrected (SIC)-like potentials for the simulation of systems with localised and strongly correlated electrons. A set of tight-binding parameters has been created to model the interaction of GaN with some dopants, including a selection of lanthanide ions interesting due to their optical or magnetic properties (Pr, Eu, Gd, Er and Tm). The f-electrons were treated as valence electrons. A qualitatively correct description of the band gap is crucial for the simulation of rare earth doped GaN, because the luminescence intensity of the implanted samples depends on the size of the host band gap and because the rare earths could introduce charge transition levels near the conduction band. In this work these levels are calculated with the Slater-Janak (SJ) transition state model, which allows an approximate calculation of the charge transition levels by analysing the Kohn-Sham eigenvalues of the DFT. (orig.)

  3. Dissolved rare earth elements in the Black Sea

    Schijf, Johan; Baar, Hein J.W. de; Wijbrans, Jan R.; Landing, William M.


    Concentrations of rare earths in the deep anoxic Black Sea are about one order of magnitude higher than in normal open ocean waters. From a minimum at the suboxic-anoxic interface at about 107 m depth, concentrations increase strongly to a maximum at about 300–400 m depth. Concentrations of Ce range

  4. XU Guangxian: Father of Chinese rare earths chemistry

    XIN Ling


    @@ Decades ago, he invented a cascade extraction theory and technique that have greatly facilitated the production of the so-called "industrial vitamins," shifting China's role from a low-profit exporter of raw ores to the world's dominant supplier of separated individual rare earth compounds and metals in high purity.

  5. Electrons and Spin Waves in Heavy Rare Earth Metals

    Mackintosh, A. R.


    Although the main principles governing the magnetic interactions and magnetic ordering in rare earth metals have been qualitatively understood for some time, it is only relatively recently that a sufficiently detailed study has been made of their electronic and magnetic excitations to place this ...

  6. Complex Electronic Structure of Rare Earth Activators in Scintillators

    Aberg, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Yu, S. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zhou, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    To aid and further the understanding of the microscopic mechanisms behind the scintillator nonproportionality that leads to degradation of the attainable energy resolution, we have developed theoretical and experimental algorithms and procedures to determine the position of the 4f energy levels of rare earth dopants relative to the host band edge states.

  7. International strategic minerals inventory summary report; rare-earth oxides

    Jackson, W.D.; Christiansen, Grey


    Bastnaesite, monazite, and xenotime are currently the most important rare-earth minerals. Bastnaesite occurs as a primary mineral in carbonatites. Monazite and xenotime also can be found in primary deposits but are recovered principally from heavy-mineral placers that are mined for titanium or tin. Each of these minerals has a different composition of the 15 rare-earth elements. World resources of economically exploitable rare-earth oxides (REO) are estimated at 93.4 million metric tons in place, composed of 93 percent in primary deposits and 7 percent in placers. The average mineral composition is 83 percent bastnaesite, 13 percent monazite, and 4 percent of 10 other minerals. Annual global production is about 67,000 metric tons of which 41 percent is from placers and 59 percent is from primary deposits; mining methods consist of open pits (94 percent) and dredging (6 percent). This output could be doubled if the operations that do not currently recover rare earths would do so. Resources are more than sufficient to meet the demand for the predictable future. About 52 percent of the world's REO resources are located in China. Ranking of other countries is as follows: Namibia (22 percent), the United States (15 percent), Australia (6 percent), and India (3 percent); the remainder is in several other countries. Conversely, 38 percent of the production is in China, 33 percent in the United States, 12 percent in Australia, and 5 percent each in Malaysia and India. Several other countries, including Brazil, Canada, South Africa, Sri Lanka, and Thailand, make up the remainder. Markets for rare earths are mainly in the metallurgical, magnet, ceramic, electronic, chemical, and optical industries. Rare earths improve the physical and rolling properties of iron and steel and add corrosion resistance and strength to structural members at high temperatures. Samarium and neodymium are used in lightweight, powerful magnets for electric motors. Cerium and yttrium increase the

  8. Pulsed field magnetization in rare-earth kagome systems

    Hoch, M. J. R.; Zhou, H. D.; Mun, E.; Harrison, N.


    The rare-earth kagome systems R 3Ga5SiO14 (R  =  Nd or Pr) exhibit cooperative paramagnetism at low temperatures. Evidence for correlated spin clusters in these weakly frustrated systems has previously been obtained from neutron scattering and from ESR and NMR results. The present pulsed field (0-60 T, 25 ms) magnetization measurements made on single crystals of Nd3Ga5SiO14 (NGS) and Pr3Ga5SiO14 (PGS) at temperatures down to 450 mK have revealed striking differences in the magnetic responses of the two materials. For NGS the magnetization shows a low field plateau, saturation in high transient fields, and significant hysteresis while the PGS magnetization does not saturate in transient fields up to 60 T and shows no hysteresis or plateaus. Nd3+ is a Kramers ion while Pr3+ is a non-Kramers ion and the crystal field effects are quite different in the two systems. For the conditions used in the experiments the magnetization behavior is not in agreement with Heisenberg model predictions for kagome systems in which easy-axis anisotropy is much larger than the exchange coupling. The extremely slow spin dynamics found below 4 K in NGS is, however, consistent with the model for Kramers ions and provides a basis for explaining the pulsed field magnetization features.

  9. Pulsed field magnetization in rare-earth kagome systems.

    Hoch, M J R; Zhou, H D; Mun, E; Harrison, N


    The rare-earth kagome systems R 3Ga5SiO14 (R  =  Nd or Pr) exhibit cooperative paramagnetism at low temperatures. Evidence for correlated spin clusters in these weakly frustrated systems has previously been obtained from neutron scattering and from ESR and NMR results. The present pulsed field (0-60 T, 25 ms) magnetization measurements made on single crystals of Nd3Ga5SiO14 (NGS) and Pr3Ga5SiO14 (PGS) at temperatures down to 450 mK have revealed striking differences in the magnetic responses of the two materials. For NGS the magnetization shows a low field plateau, saturation in high transient fields, and significant hysteresis while the PGS magnetization does not saturate in transient fields up to 60 T and shows no hysteresis or plateaus. Nd(3+) is a Kramers ion while Pr(3+) is a non-Kramers ion and the crystal field effects are quite different in the two systems. For the conditions used in the experiments the magnetization behavior is not in agreement with Heisenberg model predictions for kagome systems in which easy-axis anisotropy is much larger than the exchange coupling. The extremely slow spin dynamics found below 4 K in NGS is, however, consistent with the model for Kramers ions and provides a basis for explaining the pulsed field magnetization features.

  10. Synthesis and luminescent properties of novel pyrazolone rare earth complexes

    BAO Jiqing; TANG Chunhua; TANG Ruiren


    A novel pyrazolone pyridine-containing ligand,2,6-bis(l-phenyl-4-ethoxycarbonyl-5-pyrazolone-3-yl)pyridine(H2L)was designed and synthesized from Pyridine-2,6-dicarboxylic acid(1),and its Eu(Ⅲ)and Tb(Ⅲ)complexes were prepared.The 1igand and complexes were characterized in detailbased on FT-IR spectra,1H NMR,elemental ahalysis and thermal analysis,and the formula of Ln2L3·4H2O(Ln=Eu or Tb)of rare earth complexes was confirmed.The UV-vis absorption spectm and photoluminescence properties of the complexes were investigated,which showed that the Eu(Ⅲ)and Tb(Ⅲ)ions could be sensitized efficiently by the ligand(H2L)and emit the photoluminescence with high intensity, narrow half-peak width,and monochromic light.The results indicated that the complexes showed potential as excellent luminescent materials.

  11. Mechanisms affecting emission in rare-earth-activated phosphors



    The relatively poor efficiency of phosphor materials in cathodoluminescence with low accelerating voltages is a major concern in the design of field emission flat panel displays operated below 5 kV. The authors research on rare-earth-activated phosphors indicates that mechanisms involving interactions of excited activators have a significant impact on phosphor efficiency. Persistence measurements in photoluminescence (PL) and cathodoluminescence (CL) show significant deviations from the sequential relaxation model. This model assumes that higher excited manifolds in an activator de-excite primarily by phonon-mediated sequential relaxation to lower energy manifolds in the same activator ion. In addition to sequential relaxation, there appears to be strong coupling between activators, which results in energy transfer interactions. Some of these interactions negatively impact phosphor efficiency by nonradiatively de-exciting activators. Increasing activator concentration enhances these interactions. The net effect is a significant degradation in phosphor efficiency at useful activator concentrations, which is exaggerated when low-energy electron beams are used to excite the emission.

  12. 2011 review and outlook of China rare earth market (continued)


    5. Prices of lanthanum and cerium products decreased gradually after reaching the high Prices of lanthanum and cerium products rose rapidly with holistic price soaring in rare earth market during 2011. However, affected by the sluggish demand from international crude oil, petroleum cracking catalysts, glass, special materials and battery industries, the price dropped gradually after it hit the highest level.

  13. Rare earth metals appliance for magnetic admixtures recovery from mineral premixes

    A. A. Shevtsov


    Full Text Available The analysis of the material composition metallomagnetic admixtures of mineral premix. It is shown that the dressed metallomagnetic impurity includes low-magnetic particles with low magnetic susceptibility. Removing these particles from the product stream in process of magnetic separation using high-energy rare earth magnets is a challenging task.

  14. Progress in bulk MgCu2-type rare-earth iron magnetostrictive compounds

    Ren Wei-Jun; Zhang Zhi-Dong


    Studies of bulk MgCu2-type rare-earth iron compounds with Laves phase are reviewed.The relationship between magnetostriction and structural distortion and the consequent crystallographic method for measuring magnetostriction are introduced at first.Then we review recent progress in understanding bulk magnetostrictive Laves phase materials,especially the magnetostriction and the minimization of the anisotropy of the light rare-earth Pr-and Sm-based compounds.Finally,a summary and outlook for this kind of compounds are presented.

  15. The Link between Rare-Earth Peak Formation and the Astrophysical Site of the R Process

    Mumpower, Matthew R.; McLaughlin, Gail C.; Surman, Rebecca; Steiner, Andrew W.


    The primary astrophysical source of the rare-earth elements is the rapid neutron capture process (r process). The rare-earth peak that is seen in the solar r-process residuals has been proposed to originate as a pile-up of nuclei during the end of the r process. We introduce a new method utilizing Monte Carlo studies of nuclear masses in the rare-earth region, that includes self-consistently adjusting β-decay rates and neutron capture rates, to find the mass surfaces necessary for the formation of the rare-earth peak. We demonstrate our method with two types of astrophysical scenario, one corresponding to conditions typical of hot winds from core-collapse supernovae and stellar-mass accretion disks, and one corresponding to conditions typical of the ejection of the material from the tidal tails of neutron star mergers. In each type of astrophysical condition, this method successfully locates a region of enhanced stability in the mass surface that is responsible for the rare-earth peak. For each scenario, we find that the change in the mass surface has qualitatively different features, thus future measurements can shed light on the type of environment in which the r process occurred.

  16. Rare earth activated sintering of MoSi2 and its electric conductivity


    The effects of rare earth on activation sintering of MoSi2 and electric conductivity of the matrix were analyzed on the basis of a method proposed by German and Munir. The results show that the addition of rare earth could refine the powder size and obviously reduce sintering activation energy of MoSi2 which, for rare earth/MoSi2 system, is 83.1  kJ/mol at 1  200~14  00  ℃, about half of that of pure MoSi2. This decreases the sintering temperature of MoSi2 by about 200  ℃at least, and decreases the resistivity of the matrix as well. The mechanism of rare earth activated sintering of MoSi2 is an integrated process mostly ruled by grain boundary diffusion. When the density of materials is identical, the rare earth addition is found to have no noticeable effect on the electric conductivity of MoSi2.

  17. The link between rare earth peak formation and the astrophysical site of the $r$ process

    Mumpower, M R; Surman, R; Steiner, A W


    The primary astrophysical source of the rare earth elements is the rapid neutron capture process ($r$ process). The rare earth peak that is seen in the solar $r$-process residuals has been proposed to originate as a pile-up of nuclei during the end of the $r$ process. We introduce a new method utilizing Monte Carlo studies of nuclear masses in the rare earth region, that includes self-consistently adjusting $\\beta$-decay rates and neutron capture rates, to find the mass surfaces necessary for the formation of the rare earth peak. We demonstrate our method with two types of astrophysical scenarios, one corresponding conditions typical of core-collapse supernova winds and one corresponding to conditions typical of the ejection of the material from the tidal tails of neutron star mergers. In each type of astrophysical conditions, this method successfully locates a region of enhanced stability in the mass surface that is responsible for the rare earth peak. For each scenario, we find that the change in the mass s...

  18. Reverse engineering nuclear properties from rare earth abundances in the $r$ process

    Mumpower, M R; Surman, R; Steiner, A W


    The bulk of the rare earth elements are believed to be synthesized in the rapid neutron capture process or $r$ process of nucleosynthesis. The solar $r$-process residuals show a small peak in the rare earths around $A\\sim 160$, which is proposed to be formed dynamically during the end phase of the $r$ process by a pileup of material. This abundance feature is of particular importance as it is sensitive to both the nuclear physics inputs and the astrophysical conditions of the main $r$ process. We explore the formation of the rare earth peak from the perspective of an inverse problem, using Monte Carlo studies of nuclear masses to investigate the unknown nuclear properties required to best match rare earth abundance sector of the solar isotopic residuals. When nuclear masses are changed, we recalculate the relevant $\\beta$-decay properties and neutron capture rates in the rare earth region. The feedback provided by this observational constraint allows for the reverse engineering of nuclear properties far from ...


    A. V. Gulay


    Full Text Available Ab-Initio simulation of electronic features of sensoring nanomaterials based on rare earth oxides has been made by the example of yttrium oxide. The simulation method for thin films of nanometer scale consisted in the simulation of the material layer of the thickness equal to unit crystal cell size has been proposed within the VASP simulation package. The atomic bond breakdown in the crystal along one of the coordinate axes is simulated by the increase of a distance between the atomic layers along this axis up to values at which the value of free energy is stabilized. It has been found that the valence and conductivity bands are not revealed explicitly and the band gap is not formed in the hyperfine rare earth oxide film (at the film thickness close to 1 nm. In fact the hyperfine rare earth oxide film loses dielectric properties which were exhibited clear enough in continuum.

  20. Lime-Crusted Rammed Earth: Materials Study

    Mileto, Camilla; Vegas López-Manzanares, Fernando; Alejandre, Francisco Javier; Martín, Juan Jesús; Garcia Soriano, Lidia


    This study analyses the durability of rammed-earth wall construction techniques. The analysis focuses on three medieval masonry types from the Castle of Villavieja (Castellón, Spain) using two variations of lime-reinforced rammed earth in its walls: lime-crusted rammed earth and brick-reinforced rammed earth. Materials analysis reveals the good properties of the materials used in the outer wall facing despite its age. It also clearly shows how deterioration depends more on the construction t...

  1. Electron-phonon coupling in the rare-earth metals

    Skriver, Hans Lomholt; Mertig, I.


    We have estimated the strength of the mass enhancement of the conduction electrons due to electron-phonon interaction in the rare metals Sc, Y, and La–Lu. The underlying self-consistent energy bands were obtained by means of the scalar relativistic linear-muffin-tin-orbital method, and the electron......-phonon parameters were calculated within the Gaspari-Gyorffy formulation. For the heavier rare earths Gd–Tm spin polarization was included both in the band-structure calculations and in the treatment of the electron-phonon coupling to take into account the spin splitting of the conduction electrons induced by the 4...

  2. Optical Studies on Rare Earth Lasting Materials

    S.P. Tandon


    Full Text Available Neodymium-doped borate and phosphate glass specimens have been prepared by melt-quenching technique. Their absorption spectra have been recorded in the region 400 -900 nm. From observed absorption spectra,Judd Ofelt (J0, Omega/sub t/, parameters (t = 2, 4 and 6 have been computed. They have been used to calculate the laser parameters, viz., spontaneous emission probability (A, fluorescence branching ratio (Beeta and stimulated emission cross-section (Sigma. They exhibit the suitability of the present glass specimen for laser action. The effects of composition and concentration of the dopant on these parameters have been discussed. A comparative study of stimulated emission cross-section of different types of doped glasses has also been made.

  3. Physicochemical properties of rare earth doped ceria Ce0.9Ln0.1O1.95 (Ln = Nd, Sm, Gd) as an electrolyte material for IT-SOFC/SOEC

    Chaubey, Nityanand; Wani, B. N.; Bharadwaj, S. R.; Chattopadhyaya, M. C.


    Nanosized crystallites of rare earth doped ceria Ce0.9Ln0.1O1.95 (Ln = Nd, Sm, Gd) a promising electrolyte material for Intermediate Temperature - Solid Oxide Fuel Cells/electrolysis cells have been synthesized by standard ceramic route. Detection of impurities in the samples was done by FTIR spectroscopy. X-ray diffraction studies were used for the determination of phase purity, crystal structure and average crystallite size of the samples. Kinetics involved in phase formation has been discussed. Raman study showed a major band around 465 cm-1 in all the samples, which is attributed to the cubic fluorite structure of ceria. It was also found that for samples Ce0.9Ln0.1O1.95 (Ln = Nd, Sm, Gd) the frequency of F2g shifts to lower value. Electrochemical impedance spectroscopy has been used to measure the ionic conductivity of the samples at elevated temperatures. The Gd doped sample showed the highest grain boundary and total conductivity in comparison to Sm and Nd doped sample. Bulk thermal expansion behavior, sintered densities and micro structural features of the samples have also been studied.

  4. The occurrence of rare earth elements in some Finnish mires

    Yliruokanen, I.


    Full Text Available The content of the more abundant rare earths (RE (Y, La, Ce, Pr, Nd and Sm in the ash of 399 peat samples from 26 Finnish mires was determined by X-ray fluorescence spectrometry. The content of all rare earths (La-Lu, Y in 29 samples was also determined by spark source mass spectrometry. The median RE contents in peat ashes from areas where the bedrock consists of rapakivi granite, granite or archean gneiss are reported. Detailed data concerning the individual mires are also presented. The highest RE contents were found in samples from rapakivi granite areas where a strong negative Eu anomaly was also observed. The RE contents were in general highest at the basal peat layers.

  5. Electronic Structure of Rare-Earth Metals. II. Positron Annihilation

    Williams, R. W.; Mackintosh, Allan


    The angular correlation of the photons emitted when positrons annihilate with electrons has been studied in single crystals of the rare-earth metals Y, Gd, Tb, Dy, Ho, and Er, and in a single crystal of an equiatomic alloy of Ho and Er. A comparison of the results for Y with the calculations...... of Loucks shows that the independent-particle model gives a good first approximation to the angular distribution, although correlation effects probably smear out some of the structure. The angular distributions from the heavy rare-earth metals are very similar to that from Y and can be understood...... qualitatively in terms of the relativistic augmented-plane-wave calculations by Keeton and Loucks. The angular distributions in the c direction in the paramagnetic phases are characterized by a rapid drop at low angles followed by a hump, and these features are associated with rather flat regions of Fermi...

  6. Electronic and vibrational spectra of some rare earth trifluoromethanesulfonates crystals

    Paul, P.; Ghosh, M.; Neogy, D.; Mallick, P. K.


    The Raman and infrared spectra of some rare earth (dysprosium and terbium) trifluoromethanesulfonates crystals have been analyzed. Different vibrational frequencies of trifluoromethanesulfonate ions (CF 3SO 3-) are identified and assigned to different vibrations of the SO 3 and CF 3 groups. Electronic transitions of R 3+ ions (R = Dy, Tb) in these salts have been assigned to transitions from the ground to different energy levels of the ground multiplet. The electronic energy levels of the rare earth ions are also determined theoretically with the help of single electron crystal field theory. They are found to yield results not only in good agreement with the observed spectral data but also in good conformity with those obtained previously from magnetic measurements.

  7. Ionoluminescence of trivalent rare-earth-doped strontium barium niobate

    Calvo del Castillo, H. [Departamento de Geologia y Geoquimica, Universidad Autonoma de Madrid, Modulo C-VI, Campus de Cantoblanco, 28049 Cantoblanco, Madrid (Spain); Universidad Nacional Automoma de Mexico, Instituto de Fisica, 04510 Ciudad Universitaria, Mexico D.F. (Mexico); Ruvalcaba, J.L. [Universidad Nacional Automoma de Mexico, Instituto de Fisica, 04510 Ciudad Universitaria, Mexico D.F. (Mexico); Bettinelli, M.; Speghini, A. [Dipartimento Scientifico e Tecnologico, Universita di Verona and INSTM, UdR Verona, Ca Vignal, Strada Le Grazie 15, I-37134 Verona (Italy); Barboza Flores, M. [Centro de Investigacion en Fisica, Universidad de Sonora, Hermosillo, Sonora (Mexico); Calderon, T. [Departamento de Geologia y Geoquimica, Universidad Autonoma de Madrid, Modulo C-VI, Campus de Cantoblanco, 28049 Cantoblanco, Madrid (Spain)], E-mail:; Jaque, D.; Garcia Sole, J. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Cantoblanco, Madrid (Spain)


    Ionoluminescence spectra for different rare-earth ion (Pr{sup 3+} and Eu{sup 3+})-activated Sr{sub x}Ba{sub 1-x}Nb{sub 2}O{sub 6} strontium barium niobate crystals (x=0.33 and 0.60) have been induced with a 3 MeV proton beam for a variety of beam current intensities (45, 40 and 20 nA). The proton-beam induced luminescent spectra have shown features associated with the presence of the rare-earth ion and some spectral features mostly related to the host crystal, which appear only for high beam current intensities. We have compared the ionoluminescence results to those obtained under UV light excitation (photoluminescence technique) where a direct excitation of the band gap would occur.

  8. Magnetomigration of rare-earth ions in inhomogeneous magnetic fields.

    Franczak, Agnieszka; Binnemans, Koen; Jan Fransaer


    The effects of external inhomogenous (gradient) magnetic fields on the movement of the rare-earth ions: Dy(3+), Gd(3+) and Y(3+), in initially homogeneous aqueous solutions have been investigated. Differences in the migration of rare-earth ions in gradient magnetic fields were observed, depending on the magnetic character of the ions: paramagnetic ions of Dy(3+) and Gd(3+) move towards regions of the sample where the magnetic field gradient is the strongest, while diamagnetic ions of Y(3+) move in the opposite direction. It has been showed that the low magnetic field gradients, such the ones generated by permanent magnets, are sufficient to observe the magnetomigration effects of the ions in solution. The present work clearly establishes the behavior of magnetically different ions in initially homogeneous aqueous solutions exposed to magnetic field gradients. To this avail, a methodology for measuring the local concentration differences of metal ions in liquid samples was developed.

  9. Thermochemistry of Rare Earth Silicates for Environmental Barrier Coatings

    Costa, Gustavo; Jacobson, Nathan


    Rare earth silicates are promising candidates as environmental protective coatings (EBCs) for silica-forming ceramics and composites in combustion environments since they are predicted to have lower reactivity with the water vapor combustion products. The reactivity of rare earth silicates is assessed by the thermodynamic activity of the silica component which is best measured by Knudsen effusion mass spectrometry (KEMS). Here, we discuss a novel method based on a reducing agent to increase the partial pressure of SiO(g) which is then used to calculate thermodynamic activity of silica in Y2O3-SiO2 and Yb2O3-SiO2 systems. After the KEMS measurements, samples were probed by X-ray diffraction and their phase content was calculated from Rietveld refinement.

  10. Calcination-Digestion-Desliming of Phosphorus Ore Bearing Rare Earth

    Zhang Qin; Zhang Jie; Wang Jing; Qiu Yue qin


    The recoveries of phosphorus and RE of ore from Zhijin in Guizhou were studied.The influences of the calcination temperature, resident time, the digested time and water volume of the calcinating on concentrate yield by desliming were also investigated by orthogonal design.Appropriate calcination temperature is initial condition that makes carbonate mineral decomposition.The recovery of phosphorus is 83.02% and rare earth is 90.56% in phosphorus concentrate when calcined temperature is 900 ℃, other conditions include: calcined time is 30 min, digestion water volume is 300 ml, digestion time is 20 min.The results show that the pre-treatment of the ore is favorable for the separation and enrichment of rare earth from phosphorus ore, and a process of calcination-digestion-desliming was promised.

  11. Review of Studies on Rare Earth against Plant Disease

    慕康国; 张文吉; 崔建宇; 张福锁; 胡林


    Agricultural application of rare earth (RE) has been generalized for several decades, and it is involved in crops, vegetables and stock raising in China. However, all the researches on RE mainly focus on the fields such as plant physiological activity, physiological and biochemical mechanism, sanitation toxicology and environmental security. Plant protection by using RE and the induced resistance of plant against diseases were summarized. The mechanism of rare earth against plant disease is highlighted, which includes following two aspects. First, RE elements can control some phytopathogen directly and reduce its virulence to host plant. Another possibility is that RE elements can affect host plant and induce the plant to produce some resistance to disease.

  12. Studies on solid phase synthesis,characterization and fluorescent property of the new rare earth complexes

    Jianwei SHI


    Full Text Available Rare earth-β-diketone ligand complex luminescent material has stable chemical properties and excellent luminous property. Using europium oxide and (γ-NTA as raw materials, novel rare earth-β-dione complexes are synthesized by solid state coordination chemistry. The synthesis temperature and milling time are discussed for optimization. Experimental results show that the suitable reaction situation is at 50 ℃ and 20 h for solid-phase synthesis. The compositions and structures of the complexes are characterized by means of elemental analysis, UV-Vis and FTIR methods, and the phase stability of the complex is determined by using TG-DTA technique. It is proved that preparation of waterless binary rare earth complexes by the solid phase reaction method results in a higher product yield. The fluorescence spectra show that between Eu (Ⅲ and γ-NTA, there exists efficient energy transfer, and the rare earth complexes synthesis is an excellent red bright light-emitting material with excellent UV excited luminescence properties.

  13. Characterization of rare-earth doped Si 3 N4 /SiC micro/nanocomposites

    Peter Tatarko


    Full Text Available Influence of various rare-earth oxide additives (La2O3, Nd2O3, Sm2O3, Y2O3, Yb2O3 and Lu2O3 on the mechanical properties of hot-pressed silicon nitride and silicon nitride/silicon carbide micro/nano-composites has been investigated. The bimodal character of microstructures was observed in all studied materials where elongated β-Si3N4 grains were embedded in the matrix of much finer Si3N4 grains. The fracture toughness values increased with decreasing ionic radius of rare-earth elements. The fracture toughness of composites was always lower than that of monoliths due to their finer Si3N4/SiC microstructures. Similarly, the hardness and bending strength values increased with decreasing ionic radius of rare-earth elements either in monoliths or composites. On the other hand, the positive influence of finer microstructure of the composites on strength was not observed due to the present defects in the form of SiC clusters and non-reacted carbon zones. Wear resistance at room temperature also increased with decreasing ionic radius of rare-earth element. Significantly improved creep resistance was observed in case either of composite materials or materials with smaller radius of RE3+.

  14. Observation of anomalous phonons in orthorhombic rare-earth manganites

    Gao, P.; Chen, H. Y.; Tyson, T. A.; Liu, Z. X.; Bai, J. M.; Wang, L. P.; Choi, Y. J.; Cheong, S.-W.


    We observe the appearance of a phonon near the lock-in temperature in orthorhombic REMnO3 (RE denotes rare earth) (RE: Lu and Ho) and anomalous phonon hardening in orthorhombic LuMnO3. The anomalous phonon occurs at the onset of spontaneous polarization. No such changes were found in incommensurate orthorhombic DyMnO3. These observations directly reveal different electric polarization mechanisms in the E-type and incommensurate-type orthorhombic REMnO3.


    JIN Yingtai; ZHANG Xitian; PEI Fengkui; WU Yue


    The reaction mechanisms ofdiene polymerization with homogeneous rare earth catalyst are studied by means of the spectra of 1H- NM R, one- and two- dimensions 13C-NMR. Based on the data of above NMR spectra, it is proposed that the polymerization reaction proceeds according to the following mechanism: η4-diene (cis- (→)trans- )and η3-allyl (syn- (→)anti- ).

  16. Coherent optical ultrasound detection with rare-earth ion dopants

    Tay, Jian Wei; Longdell, Jevon


    We describe theoretical and experimental demonstration for optical detection of ultrasound using a spectral hole engraved in cryogenically cooled rare-earth ion doped solids. Our method utilizes the dispersion effects due to the spectral hole to perform phase to amplitude modulation conversion. Like previous approaches using spectral holes it has the advantage of detection with large \\'etendue. The method also has the benefit that high sensitivity can be obtained with moderate absorption contrast for the spectral holes.

  17. High photoluminescence efficiency in polymer containing rare earth

    Zhefu Wu; Qidan Ling; Xugang Shi; Jiangxin Zhang; Guangxin Zhu


    @@ Three novel kinds of polymers containing rare earth europium have been synthesized and the integrating sphere technique was employed to measure the absolute photoluminescence (PL) efficiency. The PL efficiencies were found to be up to about 40%, which indicates the potential usage in organic light emitting devices (OLED). The energy transfer from ligand to Eu ions and the 5D0 → 7F2 transition of Eu3+ were analyzed under the PL process.

  18. Rare-earth ions doped transparent oxyfluoride glass-ceramics


    In recent years, rare-earth ions doped transparent oxyfluoride glass-ceramics have attracted great attentions for their low phonon energy environments of fluoride nanocrystals and high chemical and mechanical stabilities of oxide glassy matrix. In this chapter, firstly, the crystallization behaviors of the transparent glassceramics containing CaF2 nanocrystals are presented to demonstrate the controllable microstructure evolution of nano-composites. Secondly, the optical properties of the new...

  19. Growth of oriented rare-earth-transition-metal thin films

    Fullerton, E.E.; Sowers, C.H.; Bader, S.D. [Argonne National Lab., IL (United States); Wu, X.Z. [Argonne National Lab., IL (United States)]|[Northern Illinois Univ., DeKalb, IL (United States)


    Rare-earth-transition-metal thin films are successfully grown by magnetron sputtering onto single-crystal MgO substrates with epitaxial W buffer layers. The use of epitaxial W buffer layers allows oriented single-phase films to be grown. Sm-Co films grown onto W(100), have strong in-plane anisotropy and coercivities exceeding 5 T at 5 K whereas Fe-Sm films have strong perpendicular anisotropy and are magnetically soft.

  20. Experimental Temperature and Heat Capacity in Rare Earth Nuclei

    Melby, E.; Bergholt, L.; Guttormsen, M.; Hjorth-Jensen, M.; Ingebretsen, F.; Messelt, S.; Rekstad, J.; Schiller, A.; Siem, S.; Ødegård, S. W.

    Temperature and heat capacity for the rare earth nuclei 162Dy, 166Er and 172Yb have been extracted from experimental data at the Oslo Cyclotron Laboratory (OCL). The starting point to determine thermodynamical quantities is the density of levels as a function of excitation energy. The density of accessible levels in the (3He,α γ)-reaction has been extracted from measured γ-spectra.

  1. Preparation and Characterization of Rare Earth Doped Fluoride Nanoparticles

    Timothy A. DeVol; Basak Yazgan-Kukouz; Baris Kokuoz; DiMaio, Jeffrey R.; Kevin B. Sprinkle; Tiffany L. James; Courtney J. Kucera; JACOBSOHN, Luiz G.; John Ballato


    This paper reviews the synthesis, structure and applications of metal fluoride nanoparticles, with particular focus on rare earth (RE) doped fluoride nanoparticles obtained by our research group. Nanoparticles were produced by precipitation methods using the ligand ammonium di-n-octadecyldithiophosphate (ADDP) that allows the growth of shells around a core particle while simultaneously avoiding particle aggregation. Nanoparticles were characterized on their structure, morphology, and luminesc...

  2. Correlations in rare-earth transition-metal permanent magnets

    Skomski, R., E-mail:; Manchanda, P. [Department of Physics and Astronomy and NCMN, University of Nebraska, Lincoln, Nebraska 68508 (United States); Kashyap, A. [School of Basic Science, IIT Mandi, Mandi, Himachal Pradesh (India)


    It is investigated how electron-electron correlations affect the intrinsic properties of rare-earth transition-metal magnets. Focusing on orbital moment and anisotropy, we perform model calculations for 3d-4f alloys and density-functional theory (DFT) calculations for NdCo{sub 5}. On an independent-electron level, the use of a single Slater determinant with broken spin symmetry introduces Hund's rule correlations, which govern the behavior of rare-earth ions and of alloys described by the local spin density approximation (LSDA) and LSDA + U approximations to DFT. By contrast, rare-earth ions in intermetallics involve configuration interactions between two or more Slater determinants and lead to phenomena such as spin-charge distribution. Analyzing DFT as a Legendre transformation and using Bethe's crystal-field theory, we show that the corresponding density functionals are very different from familiar LSDA-type expressions and outline the effect of spin-charge separation on the magnetocrystalline anisotropy.

  3. Existing State and Partitioning of Rare Earth on Weathered Ores


    The existing state and partitioning of rare earth (RE) on weathered ores in Longnan County (LN), Xingfeng County(XF) and Ninghua County(NH) were characterized systematically by standard geological analytical methods. It is found that RE in the weathered rare earth ores exist as four phases: (a) water soluble, (b) ion-exchangeable, (c) colloidal sediment (oxides), (d) minerals, in which mainly as ion exchangeable phase, accounting for nearly 80% of total RE,with about 20% in the form of colloid sediment phase and mineral phase, but very little as aqueous soluble phase. These rare earth partitioning were mainly chosen mid-heavy RE elements, occupying above 60%, but not equal in the four phases. The mid-heavy RE elements were primarily enriched in the ion exchangeable phase up to 40%, while the containment of cerium dioxide is below 2%. The cerium deficiency occurs in the ion exchangeable phase in weathered ore. It results from that the Ce3+ is oxidized into Ce4+ and changes into CeO2. For LN ore, the containment of Y is high in weathered ore because Y-minerals are abundant in original rock.

  4. Preparation of mixed rare earths modified chitosan for fluoride adsorption

    梁鹏; 张艺; 汪东风; 徐莹; 罗斓


    This paper described the fluoride removal from water using a new adsorbent namely mixed rare earths modified chitosan (CR). Mixed rare earths mainly contained La followed by Ce which was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). La(III)-modified chitosan (CL) was also prepared as control. For the batch technique, the effects of various parameters such as contact time, pH, adsorbent dose, initial fluoride concentration and co-ions on fluoride adsorption were studied. Fourier trans-form infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to characterize adsorbents. It was observed that the fluo-ride adsorption capacity of CR (3.72 mgF-/g) was higher than CL (3.16 mgF-/g) at 2 h. The presence of co-ions such as bicarbonate and carbonate greatly affected the fluoride adsorption from water. Characterization experiments indicated the successful chelation between mixed rare earths and chitosan. The possible fluoride adsorption mechanism of CR was explained by a chemical reaction.

  5. Recovery of rare earth metals through biosorption:An overview

    Nilanjana Das; Devlina Das


    Rare earth metals (REMs) are a series of 17 elements that have widespread and unique applications in high technology, power generation, communications, and defense industries. These resources are also pivotal to emergent sustainable energy and car-bon alternative technologies. Recovery of REMs is interesting due to its high market prices along with various industrial applications. Conventional technologies, viz. precipitation, filtration, liquid-liquid extraction, solid-liquid extraction, ion exchange, super critical extraction, electrowinning, electrorefining, electroslag refining, etc., which have been developed for the recovery of REMs, are not economically attractive. Biosorption represents a biotechnological innovation as well as a cost effective excellent tool for the recovery of rare earth metals from aqueous solutions. A variety of biomaterials such as algae, fungi, bacteria, resin, activated carbon, etc., have been reported to serve as potential adsorbents for the recovery of REMs. The metal binding mechanisms, as well as the parameters in-fluencing the uptake of rare earth metals and isotherm modeling are presented here. This article provides an overview of past achievements and current scenario of the biosorption studies carried out using some promising biosorbents which could serve as an economical means for recovering REMs. The experimental findings reported by different workers will provide insights into this re-search frontier.

  6. The valence and spectral properties of rare-earth clusters

    Peters, L; Litsarev, M S; Katsnelson, A Delin M I; Kirilyuk, A; Johansson, B; Sanyal, B; Eriksson, O


    The rare-earths are known to have intriguing changes of the valence, depending on chemical surrounding or geometry. Here we make predictions from theory that combines density functional theory with atomic multiplet-theory, on the transition of valence when transferring from the atomic divalent limit to the trivalent bulk, passing through different sized clusters, of selected rare-earths. We predict that Tm clusters show an abrupt change from pure divalent to pure trivalent at a size of 6 atoms, while Sm and Tb clusters are respectively pure divalent and trivalent up to 8 atoms. Larger Sm clusters are argued to likely make a transition to a mixed valent, or trivalent, configuration. The valence of all rare-earth clusters, as a function of size, is predicted from interpolation of our calculated results. We argue that the here predicted behavior is best analyzed by spectroscopic measurements, and provide theoretical spectra, based on dynamical mean field theory, in the Hubbard-I approximation, to ease experiment...

  7. Rare Earths of Two Types Granites in Sawuer Region, Xinjiang

    Yuan Feng; Zhou Taofa; Tan Lugui; Fan Yu; Yue Shucang


    The geochemical characteristics of rare earth elements of A type and I type granites were studied in the Sawuer region, Xinjiang. The characteristics of two types granites are different obviously,because the A type and I type granites formed at different stage of the post-collisional period. The Sentasi intrusion and Wokensala intrusion are the I type granites formed at the late of post-collisional period, and there is extrusion translating to extension stress. The characteristics of rare earth elements show that the fractional crystallization of the I type granites is indistinct, and the sources of the I type granites come from the mantle. The Kuoyitasi intrusion and Qiaqihai intrusion are the A type granites formed at the end of post-collisional period, and there is extension stress. The characteristics of rare earth elements show that the fractional crystallization of the A type granites is distinct. The sources of the A type granites come from the mantle but interfused by the crust.

  8. Restoration of rare earth mine areas: organic amendments and phytoremediation.

    Zhou, Lingyan; Li, Zhaolong; Liu, Wen; Liu, Shenghong; Zhang, Limin; Zhong, Liyan; Luo, Ximei; Liang, Hong


    Overexploitation of rare earth mine has caused serious desertification and various environmental issues, and ecological restoration of a mining area is an important concern in China. In this study, experiments involving dry grass landfilling, chicken manure broadcasting, and plant cultivation were carried out to reclaim a rare earth mine area located in Heping County, Guangdong Province, China. The prime focus was to improve soil quality in terms of nutrients, microbial community, enzyme activity, and physicochemical properties so as to reclaim the land. After 2 years of restoration, an increase of organic matter (OM), available potassium (K), available phosphorus (P) levels, and acid phosphatase (ACP) activity and a reduction of the available nitrogen (N) level and urease (URE) activity in soil were achieved compared to the original mined land. The nutrients and enzyme activities in soil with 5 years of restoration were close to or surpass those in the unexploited land as control. The bulk density, total porosity, water holding capacity, pH, and electrical conductivity (EC) of soil were improved, and the number of cultivable microorganisms and the bacterial diversity in soil were greatly increased with time during ecological restoration, especially for surface soil. Furthermore, the artificial vegetation stably grew at the restored mining sites. The results indicated that organic amendments and phytoremediation could ecologically restore the rare earth mining sites and the mined land could finally be planted as farmland.

  9. Magnetization dynamics in rare earth doped NiFe films

    Kiessling, Matthias; Woltersdorf, Georg; Back, Christian [Institut fuer Experimentelle und Angewandte Physik, Universitaet Regensburg, D- 93040 Regensburg (Germany); Thiele, Jan-Ulrich; Schabes, Manfred [Hitachi Global Storage Technologies, 3403 Yerba Buena Road, San Jose, CA 95135 (United States)


    The influence of rare earth dopants on the damping parameter and the resulting possibility to control this parameter were investigated. In our experiments NiFe films were doped with Dysprosium, Holmium, Terbium, and Gadolinium. The magnetization dynamics of these rare earth doped films was mainly studied by means of ferromagnetic resonance (FMR) and network-analyzer ferromagnetic resonance. It is demonstrated that the doping of a NiFe film by a small amount of rare earth elements (Holmium, Terbium and Dysprosium) greatly effects its magnetic relaxation rate. This additional damping is proportional to the doping level. Compared to the pure NiFe film it is possible to increase the damping parameter of the magnetic film by two orders of magnitude. On the other hand Gadolinium as a dopant has no influence on the damping parameter. For small dopant concentrations the in and out-of-plane FMR measurements at various frequencies can be well described by the same damping parameter. This is expected for the Gilbert damping term in the equation of motion. Therefore the increased damping can be attributed to an increased rate of transfer of angular momentum from the spin system to the lattice.

  10. Recovery and separation of rare Earth elements using salmon milt.

    Yoshio Takahashi

    Full Text Available Recycling rare earth elements (REEs used in advanced materials such as Nd magnets is important for the efficient use of REE resources when the supply of several REEs is limited. In this work, the feasibility of using salmon milt for REE recovery and separation was examined, along with the identification of the binding site of REEs in salmon milt. Results showed that (i salmon milt has a sufficiently high affinity to adsorb REEs and (ii the adsorption capacity of the milt is 1.04 mEq/g, which is comparable with that of commercial cation exchange resin. Heavier REEs have higher affinity for milt. A comparison of stability constants and adsorption patterns of REEs discussed in the literature suggests that the phosphate is responsible for the adsorption of REE in milt. The results were supported by dysprosium (Dy and lutetium (Lu LIII-edge extended x-ray absorption fine structure (EXAFS spectroscopy. The REE-P shell was identified for the second neighboring atom, which shows the importance of the phosphate site as REE binding sites. The comparison of REE adsorption pattern and EXAFS results between the milt system and other adsorbent systems (cellulose phosphate, Ln-resin, bacteria, and DNA-filter hybrid revealed that the coordination number of phosphate is correlated with the slope of the REE pattern. The separation column loaded with milt was tested to separate REE for the practical use of salmon milt for the recovery and separation of REE. However, water did not flow through the column possibly because of the hydrophobicity of the milt. Thus, sequential adsorption-desorption approach using a batch-type method was applied for the separation of REE. As an example of the practical applications of REE separation, Nd and Fe(III were successfully separated from a synthetic solution of Nd magnet waste by a batch-type method using salmon milt.

  11. Crystal Fields in Dilute Rare-Earth Metals Obtained from Magnetization Measurements on Dilute Rare-Earth Alloys

    Touborg, P.; Høg, J.


    Crystal field parameters of Tb, Dy, and Er in Sc, Y, and Lu are summarized. These parameters are obtained from magnetization measurements on dilute single crystals, and successfully checked by a number of different methods. The crystal field parameters vary unpredictably with the rare-earth solute....... B40, B60, and B66 are similar in Y and Lu. Crystal field parameters for the pure metals Tb, Dy, and Er are estimated from the crystal fields in Y and Lu....

  12. Investigations into Rare Earth Oxide Use and Behaviour

    Pryce, Owen


    The use of tracers which are applied to soils (distinguishable from tracers naturally present in soils) is increasing. Rare earth oxides (REOs) are the most prevalent of the sediment tracers used to tag soils in this manner. REOs have been applied in a host of different countries, at a range of scales e.g. over watersheds in the USA (Polyakov and Nearing, 2004; Kimoto et al., 2006); to examine rill erosion in China (Li et al., 2006); and to investigate the importance of topographical features in arable fields in the EU (Stevens and Quinton, 2008). Many successful experiments have been conducted using the suit of REO tracers, yielding important information on the behaviour of eroding sediments. However, the majority of publications have focused upon application of REO tracers, applying the tagging and extraction methods developed by Zhang et al., (2001, 2003). Furthermore, the techniques presently being used are known to generate methodological inaccuracies, such as tracer enrichment and non-uniform REO distributions on experimental plots, and analytical interferences when ICP-MS is used for tracer quantification. Unanswered questions regarding the use of REO tracers include: i) what is the effect upon soil of REO tagging?; ii) how is a uniform distribution of REOs in tagged soil achieved? iii) which is the most suitable way of applying REOs, to experimental plots of different scale, and to meet different objectives?; iv) which REOs are unsuitable for sediment tracing?; v) what is the most precise and efficient method of extracting REO tracers from sediments? vi) is the transport behaviour of REO tracers comparable to untagged soils? In an attempt to answer some of these questions, investigations have been conducted into the effect upon soil particle size of different methods of REO tagging. The ability of these methods to provide uniform distributions of REOs in the tagged soil was calculated. The accuracy and precision of published (Zhang et al., 2003; Stevens and

  13. Dry Friction and Wear Characteristics of Rare-Earth/MoSi2 Composite

    张厚安; 龙春光; 陈平; 刘心宇


    The dry friction and wear characteristics of rare earth/MoSi2 composite against 45 steel under different loads were investigated by using an M-200 type friction and wear tester. SEM and XRD were used to analyze the morphology of the friction surface and the phase of worn piece in order to reveal the wear mechanism of rare-earth/MoSi2 composite. Results show that the relationships of friction coefficient, μ, or wear rate, W, of MoSi2 and RE/MoSi2 composite to loads, p, can be fitted well with the following function: μ(or W)= a+bp+cp2+dp3+ep4, where a, b, c, d and e are fitting constants depending on materials and confidence. MoSi2 and rare-earth/MoSi2 composite have excellent wear resistance. When load is in the range of 80~120 N, the wear rate of RE/MoSi2 composite is lower than that of MoSi2 material by about 65%. The main wear mechanism of rare-earth/MoSi2 composite is adhesive wear.

  14. A study on the deactivation of USY zeolites with different rare earth contents

    Henriques, C.A.; Santos, J.O.J. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Quimica; Polato, C.M.S.; Valle, Murta; Aguiar, E.F.S. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica; Monteiro, J.L.F. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Nucleo de Catalise


    The deactivation of USY zeolites different rare earth contents due to the coke formed n-heptane at 450 deg C was studied. The results show that the presence of rare earth elements decreases the cracking and coking activities, increasing catalytic stability. However, reaction selectivity was not significantly influenced. The greater the rare earth content, the lower the cocking rates and the coke contents. The TPO/DSC profiles suggested that the catalytic effect of the rare earth elements promoted coke oxidation. (author)

  15. Structure and properties of intermetallic ternary rare earth compounds

    Casper, Frederick


    The so called material science is an always growing field in modern research. For the development of new materials not only the experimental characterization but also theoretical calculation of the electronic structure plays an important role. A class of compounds that has attracted a great deal of attention in recent years is known as REME compounds. These compounds are often referred to with RE designating rare earth, actinide or an element from group 1-4, M representing a late transition metal from groups 8-12, and E belonging to groups 13-15. There are more than 2000 compounds with 1:1:1 stoichiometry belonging to this class of compounds and they offer a broad variety of different structure types. Although many REME compounds are know to exist, mainly only structure and magnetism has been determined for these compounds. In particular, in the field of electronic and transport properties relatively few efforts have been made. The main focus in this study is on compounds crystallizing in MgAgAs and LiGaGe structure. Both structures can only be found among 18 valence electron compounds. The f electrons are localized and therefor not count as valence electrons. A special focus here was also on the magnetoresistance effects and spintronic properties found among the REME compounds. An examination of the following compounds was made: GdAuE (E=In,Cd,Mg), GdPdSb, GdNiSb, REAuSn (RE=Gd,Er,Tm) and RENiBi (RE=Pr,Sm,Gd-Tm,Lu). The experimental results were compared with theoretic band structure calculations. The first half metallic ferromagnet with LiGaGe structure (GdPdSb) was found. All semiconducting REME compounds with MgAgAs structure show giant magnetoresistance (GMR) at low temperatures. The GMR is related to a metal-insulator transition, and the value of the GMR depends on the value of the spin-orbit coupling. Inhomogeneous DyNiBi samples show a small positive MR at low temperature that depends on the amount of metallic impurities. At higher fields the samples show a

  16. The Association of China Rare Earth Industry Founded to Cope with International Trade Disputes


    <正>On April 8,the long-awaited Association of China Rare Earth Industry was eventually founded in Beijing.The association is composed of 155 members including Chinalco, Minmetals,Baotou Steel Group and Ganzhou Rare Earth,etc.,covering nearly all rare earth

  17. Life cycle inventory of the production of rare earths and the subsequent production of NdFeB rare earth permanent magnets.

    Sprecher, Benjamin; Xiao, Yanping; Walton, Allan; Speight, John; Harris, Rex; Kleijn, Rene; Visser, Geert; Kramer, Gert Jan


    Neodymium is one of the more critical rare earth elements with respect to current availability and is most often used in high performance magnets. In this paper, we compare the virgin production route of these magnets with two hypothetical recycling processes in terms of environmental impact. The first recycling process looks at manual dismantling of computer hard disk drives (HDDs) combined with a novel hydrogen based recycling process. The second process assumes HDDs are shredded. Our life cycle assessment is based both on up to date literature and on our own experimental data. Because the production process of neodymium oxide is generic to all rare earths, we also report the life cycle inventory data for the production of rare earth oxides separately. We conclude that recycling of neodymium, especially via manual dismantling, is preferable to primary production, with some environmental indicators showing an order of magnitude improvement. The choice of recycling technology is also important with respect to resource recovery. While manual disassembly allows in principle for all magnetic material to be recovered, shredding leads to very low recovery rates (<10%).

  18. EU FP7 EREAN training network offers (c)lean recycling solutions for rare-earth magnets


    EREAN is the European Rare Earth Magnet Recycling Network which started its activities in September 2013. It trains 15 young researchers in the direct and indirect recycling of NdFeB permanent magnets. The innovative aspect of the EREAN project is that it addresses the whole materials loop from End-of-Life consumer goods to recycling and the production of new REE magnets, with an integrated life cycle assessment. As is highlighted by the European Rare Earths Competency Network (ERECON),...

  19. EU FP7 EREAN training network offers (c)lean recycling solutions for rare-earth magnets

    Binnemans, Koen; Jones, Peter Tom


    EREAN is the European Rare Earth Magnet Recycling Network which started its activities in September 2013. It trains 15 young researchers in the direct and indirect recycling of NdFeB permanent magnets. The innovative aspect of the EREAN project is that it addresses the whole materials loop from End-of-Life consumer goods to recycling and the production of new REE magnets, with an integrated life cycle assessment. As is highlighted by the European Rare Earths Competency Network (ERECON),...

  20. Radiation effects on rare-earth doped optical fibers

    Girard, S.; Marcandella, C. [CEA Bruyeres-le-Chatel, DIF 91 (France); Ouerdane, Y.; Tortech, B.; Boukenter, A.; Meunier, J.P.; Vivona, M. [Lab. Hubert Curien, CNRS, 42 - Saint-Etienne (France); Vivona, M.; Robin, Th.; Cadier, B. [iXFiber SAS, 22 - lannion (France)


    In this paper, we reviewed our previous work concerning the responses of rare-earth (RE) doped fibers (Yb, Er and Er/Yb) to various types of radiations like gamma-rays, X-rays and protons. For all these harsh environments, the main measured macroscopic radiation-induced effect is an increase of the linear attenuation of these waveguides due to the generation of point defects in the RE-doped core and silica-based cladding. To evaluate the vulnerability of this class of optical fibers for space missions, we characterize the growth and decay kinetics of their radiation-induced attenuation (RIA) during and after irradiation for various compositions. Laboratory testing reveals that this class of optical fibers is very sensitive to radiations compared to passive (RE-free) samples. As a consequence, despite the small length used for space applications, the understanding of the radiation-induced effects in this class of optical fibers becomes necessary before their integration as part of fiber-based systems like gyroscopes or communication systems. In this paper, we more particularly discussed about the relative influence of the rare-earth ions (Er{sup 3+} and/or Yb{sup 3+}) and of the glass matrix dopants (Al, P, ... ) on the optical degradation due to radiations. This has been done by using a set of five prototype optical fibers designed by the fiber manufacturer iXFiber SAS to enlighten the role of these parameters. Additional spectroscopic tools like con-focal microscopy of luminescence are also used to detect possible changes in the spectroscopy of the rare-earth ions and their consequences on the functionality of the active optical fibers. (authors)

  1. Solution thermodynamics of rare-earth metal ions - physicochemical study-

    Amerkhanova, Sh K; Shlyapov, R M; Uali, A S [Buketov Karaganda state university, University str., 28, Karaganda, 100028 (Kazakhstan)], E-mail:


    The results of the studying of interactions in multicomponent systems 'polyvinyl alcohol (PVA) - rare-earth element ion - nitrate of sodium - water' are represented. It is established that for rubidium (I) ions temperature and ionic strength is render destroying action, and for yttrium (III) ions the influence of these factors has return character which is connected with features of an electronic structure of metal ion. It is revealed that a dominating role of non-electrostatic formation composed, hence, the formation of donor-acceptor connection of 'metal - ligand' occurs through atom of oxygen.

  2. Thermoluminescence dosimetry of rare earth doped calcium aluminate phosphors

    K Madhukumar; K Rajendra Babu; K C Ajith Prasad; J James; T S Elias; V Padmanabhan; C M K Nair


    The thermoluminescence (TL) properties of calcium aluminate (CaAl2O4) doped with different rare earth ions have been studied and their suitability for radiation dosimetry applications is discussed. It is observed that monocalcium aluminate doped with cerium is a good dosimeter having linear response up to about 4 kGy of radiation doses. Dopant concentration of 0.25 mol% cerium gives maximum TL emission. The well-defined single peak observed at 295°C can be advantageously used for high temperature dosimetry applications.

  3. Synthesis and Characterization of Rare Earth Complexes of Ferrocenylcarbonylhydrazine

    边占喜; 董彬; 李保国


    Rare earth complexes of ferrocenylcarbonylhydrazine Ln(FH)x(ClO4)3*nH2O (where Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, x=3; Ln = Er, Tm, Yb, Lu, x=4; n=2~6, FH=ferrocenylcarbonylhydrazin) were synthesized and characterized by elemental analyses, MS, IR and 1H NMR spectra. The ligand FH is bidentate, coordinating through the carbonyl oxygen and the amino nitrogen atom. The redox properties of the ligand and its complexes were investigated using cyclic voltammetric method. The solid state fluorescence spectra of Sm, Tb and Dy complexes were also studied.

  4. Resonance electronic Raman scattering in rare earth crystals

    Williams, G.M.


    The intensities of Raman scattering transitions between electronic energy levels of trivalent rare earth ions doped into transparent crystals were measured and compared to theory. A particle emphasis was placed on the examination of the effect of intermediate state resonances on the Raman scattering intensities. Two specific systems were studied: Ce/sup 3 +/(4f/sup 1/) in single crystals of LuPO/sub 4/ and Er/sup 3 +/(4f/sup 11/) in single crystals of ErPO/sub 4/. 134 refs., 92 figs., 33 tabs.

  5. Preparation of Rare-Earth Composite Ferrite Magnetic Fluid

    蒋荣立; 刘永超; 刘守坤; 鞠明礼


    Water-based rare-earth ferrite (RexFe3-xO4)magnetic fluids were prepared by chemical co-precipitation method. The result shows that saturation magnetic intensity of ferrite magnetic fluids can be improved by adding Dy3+ and the saturation magnetic intensity will reach the highest if n(Fe)∶n(Dy3+)=30∶1. The modification and formation mechanism of RexFe3-xO4 particles is discussed in detail. The physicochemical properties are investigated by the Gouy magnetic balance, IR, TEM, XRD, and EDX, etc.

  6. Review, Intelligence and Development of Rare Earths during Biological Evolution

    Qiu Guanming; Li Wei; Zhang Ming; Li Zhe; Yan Changhao; Li Yourong; Ding Guohui


    The relationship between organism and rare earth elements (REE) viewed from evolution was discussed.Some metal ions play key roles in biological functions, however, as the illustration in this article shows, with powerful affinities for oxygen and similar radius, REE can display equally or even more important functions in terms of its biological functions. These attractive characteristics have called more public attention and lead to many applications in agriculture, medicine fields, etc. Furthermore, the article employed the concept of entropy to discuss the dosage effect of REE on organism and the possibility whether REE can become a portion of organism during the evolution.

  7. Mother Lode: The Untapped Rare Earth Mineral Resources of Vietnam


    hundreds of Bq/m 3 of air; the recommended safety limits for civilian exposure are 3.5 mSv/year and 0.15 Bq/m 3 , respectively. 37 REO Mining – a...Commission for Asia and the Pacific. Atlas of Mineral Resources of the ESCAP Region, Vol. 6, Viet Nam. ST/ESCAP/831. Bangkok : UNESCAP, 1990. “US$ 35.5... Bangkok ), July 19, 2013. ProQuest (1400734925). “VINACOMIN and Japanese Firm to Exploit and Process Rare Earth in Lai Chau.” Vietnam National

  8. Electron microscopy of microwave-synthesized rare-earth chromites

    Schmidt, Rainer; Prado-Gonjal, Jesus; Avila, David; Amador, Ulises; Moran, Emilio


    The perovskite rare-earth (RE) chromite series (RE)CrO3 (RE = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb, Lu) has been synthesized in our laboratory using microwave techniques. In this work we will demonstrate how X-ray diffraction (XRD), Rietveld refinement of XRD pattern and complementary High Resolution Transmission Electron Microscopy (HRTEM) were used to confirm that the desired crystal structure had been formed. Field-emission scanning electron microscopy (FE-SEM) gave clear ...

  9. Effect of Rare Earth Elements on Quantity Growth of Ctrps

    张自立; 常江; 等


    The effects of rare earth on the growth of rice,rape and soybean in three kinds of soils were studied with the method supposed by Economic Co-operation and Development organization(OECD),and the EC50(median growth concenrtation)values were obtained,The inhibition of RE on the growth of rice and rape in red soil and on the growth of soybeanin yellow fouvo-aquic soil is higher with stronger poison effects.Compared with other heavy metals such as Hg,Cd,Pb,As,the poison of RE on crops in weaker.

  10. Effect of Rare Earth Elements on Quantity Growth of Crops

    张自立; 常江; 汪成胜; 柴绍明; 韩修明; 李瑞


    The effects of rare earth on the growth of rice, rape and soybean in three kinds of soils were studied with the method supposed by Economic Co-operation and De velopment organization (OECD), and the EC50(median growth concentration)value s were obtained . The inhibition of RE on the growth of rice and rape in red soil and on the gro wth of soybean in yellow fluvo-aquic soil is higher with stronger poison effect s. Compared with other heavy metals such as Hg, Cd, Pb, As, the poison of RE on crops is weaker.

  11. Synthesis and luminescence of some rare earth metal complexes

    Bochkarev, Mikhail N.; Pushkarev, Anatoly P.


    In the present paper the synthesis, photoand electroluminescent properties of new rare earth metal complexes prepared and studied at the Razuvaev Institute of Organometallic Chemistry during the last decade are reviewed. The obtained compounds give luminescence in UV, visible and NIR regions. The substituted phenolates, naphtholates, mercaptobenzothiazolate, 8-oxyquinolinolate, polyfluorinated alcoholates and chalcogenophosphinates were used as ligands. The synthesis and structure of unusual three-nuclear sulfidenitride clusters of Nd and Dy are described. The new excitation mechanism of ytterbium phenolates and naphtholates, which includes the stage of reversible reduction of Yb to divalent state and oxidation of the ligands in the excitation process, is discussed.

  12. Luminescence enhancement of rare earth ions by metal nanostructures



    Well-ordered metal structures,i.e.arrays of nanosized tips on silver surface for studies of the luminescence enhancement of absorbed media with rare earth ions were used.These arrays were prepared by the metal evaporation on track membranes.Calculations of resonance frequencies of tips regarded as semispheroids were done taking into account the interaction between dipoles of tips.They were used to discuss experimental results for media with Eu(NO3)3·6H2O salt basing on data for bulk silver dielectric function.

  13. Influence of Rare Earths on Contact Fatigue of Rail Steels


    Rail/wheel contact fatigue of NbRE rail, Nb rail and U74 rail was investigated using contact fatigue tester. Microstructure and morphology as well as microhardness in the fatigue profiles were analyzed by scanning electron microscope and Vickers hardness respectively. The experimental results show that rare earths are able to delay the initiation and the propagation of fatigue cracks and postpone the surface shelling or spalling, even more, to reduce the crack propagation angle and the crack propagation depth in steady state as well as the plastic deformation area, and to improve work-hardening of the rail steel.

  14. Charge Penetration Effects in Rare-Earth Crystal Fields.


    Interactions, 3. Three-Parameter Theory of Crystal Fields, Harry Diamond Laboratories HDL-TR-1673 (June 1975). 2R. M. Sternheimer , Phys. Rev., 84 (1951...R. M. Sternheimer , Phys. Rev., 84 (1951), 244. (3) R. E. Watson and A. J. Freeman, Phys. Rev., 135 (1964), A1209. (4) D. Sengupta and J. 0. Artman...A RARE-EARTH ION INTO THE CHARGE DI! THE RESULTS ARE CAST INTO A FORM REMINISCENT OF THE STERNHEIMER SHIELDING FA( A PRIME NM(R TO THE NTH POWER) TO

  15. Structural, electronic, mechanical and magnetic properties of rare earth nitrides REN (RE= Pm, Eu and Yb)

    Murugan, A. [Department of physics, N.M.S.S.V.N college, Madurai, Tamilnadu 625019 (India); Rajeswarapalanichamy, R., E-mail: [Department of physics, N.M.S.S.V.N college, Madurai, Tamilnadu 625019 (India); Santhosh, M. [Department of physics, N.M.S.S.V.N college, Madurai, Tamilnadu 625019 (India); Iyakutti, K. [Department of physics and Nanotechnology, SRM University, Chennai, Tamilnadu 603203. India. (India)


    The structural, electronic and mechanical properties of rare earth nitrides REN (RE=Pm, Eu and Yb) are investigated in NaCl and CsCl, and zinc blende structures using first principles calculations based on density functional theory. The calculated lattice parameters are in good agreement with the available results. Among the considered structures, these nitrides are most stable in NaCl structure. A pressure induced structural phase transition from NaCl to CsCl phase is observed in all these nitrides. The electronic structure reveals that these rare earth nitrides are half metallic at normal pressure. These nitrides are found to be covalent and ionic in the stable phase. The computed elastic constants indicate that these nitrides are mechanically stable and elastically anisotropic. Our results confirm that these nitrides are ferromagnetic in nature. A ferromagnetic to non-magnetic phase transition is observed at the pressures of 21.5 GPa and 46.1 GPa in PmN and YbN respectively. - Highlights: • Rare earth nitrides PmN, EuN and YbN are found to be ferromagnetic in nature. • Electronic, structural, elastic and mechanical properties of rare earth nitrides are investigated. • A pressure induced structural phase transition is predicted under high pressure. • Electronic structure reveals that these materials exhibit half-metallic behavior. • Computed elastic moduli obey the mechanical stability condition.

  16. Nanophotonic coherent light-matter interfaces based on rare-earth-doped crystals

    Zhong, Tian; Kindem, Jonathan M.; Miyazono, Evan; Faraon, Andrei


    Quantum light-matter interfaces connecting stationary qubits to photons will enable optical networks for quantum communications, precise global time keeping, photon switching and studies of fundamental physics. Rare-earth-ion-doped crystals are state-of-the-art materials for optical quantum memories and quantum transducers between optical photons, microwave photons and spin waves. Here we demonstrate coupling of an ensemble of neodymium rare-earth-ions to photonic nanocavities fabricated in the yttrium orthosilicate host crystal. Cavity quantum electrodynamics effects including Purcell enhancement (F=42) and dipole-induced transparency are observed on the highly coherent 4I9/2-4F3/2 optical transition. Fluctuations in the cavity transmission due to statistical fine structure of the atomic density are measured, indicating operation at the quantum level. Coherent optical control of cavity-coupled rare-earth ions is performed via photon echoes. Long optical coherence times (T2~100 μs) and small inhomogeneous broadening are measured for the cavity-coupled rare-earth ions, thus demonstrating their potential for on-chip scalable quantum light-matter interfaces.

  17. Ground-state properties of rare-earth metals: an evaluation of density-functional theory.

    Söderlind, Per; Turchi, P E A; Landa, A; Lordi, V


    The rare-earth metals have important technological applications due to their magnetic properties, but are scarce and expensive. Development of high-performance magnetic materials with less rare-earth content is desired, but theoretical modeling is hampered by complexities of the rare earths electronic structure. The existence of correlated (atomic-like) 4f electrons in the vicinity of the valence band makes any first-principles theory challenging. Here, we apply and evaluate the efficacy of density-functional theory for the series of lanthanides (rare earths), investigating the influence of the electron exchange and correlation functional, spin-orbit interaction, and orbital polarization. As a reference, the results are compared with those of the so-called 'standard model' of the lanthanides in which electrons are constrained to occupy 4f core states with no hybridization with the valence electrons. Some comparisons are also made with models designed for strong electron correlations. Our results suggest that spin-orbit coupling and orbital polarization are important, particularly for the magnitude of the magnetic moments, and that calculated equilibrium volumes, bulk moduli, and magnetic moments show correct trends overall. However, the precision of the calculated properties is not at the level of that found for simpler metals in the Periodic Table of Elements, and the electronic structures do not accurately reproduce x-ray photoemission spectra.

  18. Rare Earth Elements: Overview of Mining, Mineralogy, Uses, Sustainability and Environmental Impact

    Nawshad Haque


    Full Text Available Rare earths are used in the renewable energy technologies such as wind turbines, batteries, catalysts and electric cars. Current mining, processing and sustainability aspects have been described in this paper. Rare earth availability is undergoing a temporary decline due mainly to quotas being imposed by the Chinese government on export and action taken against illegal mining operations. The reduction in availability coupled with increasing demand has led to increased prices for rare earths. Although the prices have come down recently, this situation is likely to be volatile until material becomes available from new sources or formerly closed mines are reopened. Although the number of identified deposits in the world is close to a thousand, there are only a handful of actual operating mines. Prominent currently operating mines are Bayan Obo in China, Mountain Pass in the US and recently opened Mount Weld in Australia. The major contributor to the total greenhouse gas (GHG footprint of rare earth processing is hydrochloric acid (ca. 38%, followed by steam use (32% and electricity (12%. Life cycle based water and energy consumption is significantly higher compared with other metals.

  19. Perspectives for the recovery of rare earths from end-of-life fluorescent lamps

    K Binnemans; PT Jones


    This vision paper discusses the advantages and disadvantages of the three main options for the recycling of rare-earth ele-ments from end-of-life fluorescent lamps:(1) direct re-use of the lamp phosphor mixture;(2) separation of the lamp phosphor mixture into the different phosphor components; (3) recovery of the rare-earth content. An overview is given of commercial activities in Europe in the domain of recycling of materials from end-of-life fluorescent lamps and the recovery of rare earths from these lamps. The collection of end-of-life fluorescent lamps is currently driven by a legal framework that prohibited the release of mercury to the environment. The contaminations of the lamp phosphor powders by mercury and by small glass particles of crushed fluorescent lamps are limiting factors in the recycling process. Research should be directed to an advanced clean-up of the reclaimed lamp phosphor fraction, and in particular to the removal of mercury and glass fragments. The recovery of rare earths from the lamp phosphors could be facilitated by taking advantage of the differences in resistance of the different lamp phosphors by chemical attack by inorganic ac-ids and bases.

  20. Structural and crystal chemical properties of rare-earth double phosphates and rare-earth titanate pyrochlores

    Farmer, J. Matt

    Alkali rare-earth double phosphates have been studied for use as long-wavelength scintillators for gamma-ray detection using Si photodiodes. These compounds exhibit layered crystal structures, built from roughly hexagonal atomic layers in the sequence lanthanide, phosphate-alkali, alkali, alkali-phosphate. Details of the crystal symmetry depend on the relative sizes of the rare-earth and alkali metal ions. Single-crystal X-ray diffraction (SXRD) has been used to study these structures at room temperature for K3RE(PO4) 2 (where RE = Lu-Ce, Y, and Sc). The compound K3Lu(PO 4)2 crystallizes with a hexagonal unit cell, space group P-3. The Lu ion is six-coordinated to the oxygen atoms of the phosphate groups. Two lower-temperature phases of K3Lu(PO4) 2 were observed and characterized. The lower-temperature transition results in an increase in coordination of the Lu ion to seven fold. This new structure is isostructural with the room-temperature form of K3Yb(PO 4)2. High-temperature powder neutron diffraction and high-temperature powder XRD have revealed a large thermal expansion anisotropy for K3Lu(PO4)2. The K3RE(PO 4)2 formation enthalpies were determined using high-temperature oxide-melt solution calorimetry. The formation enthalpy from oxides becomes more exothermic with increasing rare-earth radius. Rare-earth titanates, RE2Ti2O7 (where RE = a rare-earth), with the pyrochlore structure are currently being studied for use as potential nuclear, actinide-rich waste forms. Single-crystals were synthesized using a high-temperature flux technique and characterized using single-crystal X-ray diffraction. The cubic lattice parameters display an approximately linear correlation with the RE-site cation radius. The Sm and Eu titanates exhibit a covalency increase between the REO8 and TiO6 polyhedra resulting in a deviation from the increasing linear lattice parameter through the series. Gd2Ti2O7 exhibits the lowest 48f oxygen positional parameter, an effect that can be

  1. Review and outlook for China rare earth industry in recent years

    By Lihua ZHANG; Mingsheng YANG; Xiaofang LIU


    @@ Guided by related policies, China rare earth industry is actively transferring its economic development pattern in recent two years.Series of effective economic stimulus policies and measures were adopted, which further standardize rare earth mining, production and export market.Chinese rare earth industry had finally overcome difficulties brought by global financial crisis and production and marketing in the industry were gradually improved.In 2009, rare earth business thoroughly reversed the unprofitable situation.Total production value exceeded 24 billion yuan in the year.With global economy recovery in 2010, rare earth industry entered into a rapid development period.

  2. High quality factor nanophotonic resonators in bulk rare-earth doped crystals

    Zhong, Tian; Kindem, Jonathan M; Miyazono, Evan; Faraon, Andrei


    Numerous bulk crystalline materials exhibit attractive nonlinear and luminescent properties for classical and quantum optical applications. A chip-scale platform for high quality factor optical nanocavities in these materials will enable new optoelectronic devices and quantum light-matter interfaces. In this article, photonic crystal nanobeam resonators fabricated using focused ion beam milling in bulk insulators, such as rare-earth doped yttrium orthosilicate and yttrium vanadate, are demonstrated. Operation in the visible, near infrared, and telecom wavelengths with quality factors up to 27,000 and optical mode volumes close to one cubic wavelength is measured. These devices enable new nanolasers, on-chip quantum optical memories, single photon sources, and non-linear devices at low photon numbers based on rare-earth ions. The techniques are also applicable to other luminescent centers and crystals.

  3. Structural And Electrical Properties Of The Selected Rare-Earth Oxychlorides

    Dziubaniuk M.


    Full Text Available The preparation and sintering conditions of the selected rare-earth oxychlorides REOCl (Re=La, Nd, Sm, Gd were determined. The purity of materials phase compositions was confirmed by X-ray diffraction method. Further analysis of the data enabled lattice parameters and average grain size determination. The electrical properties of the single phase REOCl materials were investigated by Electrochemical Impedance Spectroscopy in wide temperature range in atmospheric air. The spectra were analyzed by the equivalent circuit fitting. Basing on the values of equivalent circuits parameters the specific conductivities were calculated and presented in the Arrhenius coordinates. Energies of activation were calculated. The determined structural and electrical properties of four different rare-earth oxychlorides were directly compared.

  4. Enhanced Laser Cooling of Rare-Earth-Ion-Doped Glass Containing Nanometer-Sized Metallic Particles

    JIA You-Hun; ZHONG Biao; YIN Jian-Ping


    The enhanced laser cooling performance of rare-earth-ions-doped glasses containing small particles is predicted. This is achieved by the enhancement of local field around rare earth ions, owing to the surface plasmon resonance of small metallic particles. The role of energy transfer between ions and the particle is theoretical discussed. Depending on the particle size and the ion emission quantum efficiency, the enhancement of the absorption and the fluorescence is predicted. Moreover, taking Yb3+-doped ZBLAN as example, the cooling power and heat-light converting efficiency are calculated. It is finally concluded that the absorption and the fluorescence are greatly enhanced in these composite materials, the cooling power is increased compared to the bulk material.

  5. Rare Earth elements as sediment tracers in Mangrove ecosystems

    Ramanathan, A. L.; Swathi, S.


    Rare earth elements have been widely used as geochemical source fingerprints of rocks and sediments to study processes involving cosmo-chemistry, igneous petrology, tectonic setting and for investigations of water-rock interactions and weathering processes including transport of weathering products to the oceans.Many studies have addressed the use of REEs in investigating the environmental impact of human activity and demonstrated that the REE natural distribution in sediment from densely industrialised and populated regions can be altered by anthropogenic influences.The coastal wetlands like Mangroves are ultimate sinks for all the material derived from the terrestrial and marine environment.The high productivity and low ratio of sediment respiration to net primary production gives mangrove sediments the potential for long-term sequestration of these pollutants/metals before reaching the coastal ocean. Geochemical study of REE in these sedimentary systems is useful for determining the nature of the biogeochemical processes. In particular, REE show a great sensitivity to pH changes, redox conditions and adsorption/ desorption reactions. So, they may be used as markers of discharge provenance, weathering processes, changes in environmental conditions in the water and sediments of Mangrove/wetland systems. Our study aims to establish the abundance, distribution and enrichment of REEs to track the sediment sources and biogeochemical processes occurring in the mangrove environment.Core sediments were collected from the different environmental settings within the Pichavaram mangrove area.Higher REE concentration in Pichavaram sediments indicated greater input from sources like terrestrial weathering and anthropogenic activities which in turn are affected by saline mixing and dynamic physico-chemical processes occurring in the mangrove environment. REE enrichment order was attributed to the alkaline pH (7-8.5) and reducing conditions prevailing in the mangrove

  6. MBE growth and characterisation of light rare-earth superlattices

    Ward, R.C.C.; Wells, M.R.; Bryn-Jacobsen, C.


    The molecular beam epitaxy growth techniques which have already successfully produced a range of heavy rare-earth superlattices have now been extended to produce superlattices of two light rare-earth elements, Nd/Pr, as well as superlattices and alloy films of a heavy/light system, Ho/Pr. High......-resolution X-ray diffraction analysis shows the Nd/Pr superlattices to be of high structural quality, while the Ho/Pr superlattices are significantly less so. In the Ho/Pr superlattices, Pr is found to retain its bulk dhcp crystal structure even in thin layers (down to 6 atomic planes thick) sandwiched between...... thick layers of hcp Ho. In addition, neutron diffraction studies of the He/Pr superlattices have shown that the helical Ho magnetic order is not coherent through the dhcp Pr layers, in contrast to previous hcp/hcp superlattices Ho/Y, Ho/Lu and Ho/Er. The series of Ho:Pr alloy films has shown structural...

  7. Homometallic rare-Earth metal phosphinidene clusters: synthesis and reactivity.

    Wang, Kai; Luo, Gen; Hong, Jianquan; Zhou, Xigeng; Weng, Linhong; Luo, Yi; Zhang, Lixin


    Two new trinuclear μ3 -bridged rare-earth metal phosphinidene complexes, [{L(Ln)(μ-Me)}3 (μ3 -Me)(μ3 -PPh)] (L=[PhC(NC6 H4 iPr2 -2,6)2 ](-) , Ln=Y (2 a), Lu (2 b)), were synthesized through methane elimination of the corresponding carbene precursors with phenylphosphine. Heating a toluene solution of 2 at 120 °C leads to an unprecedented ortho CH bond activation of the PhP ligand to form the bridged phosphinidene/phenyl complexes. Reactions of 2 with ketones, thione, or isothiocyanate show clear phospha-Wittig chemistry, giving the corresponding organic phosphinidenation products and oxide (sulfide) complexes. Reaction of 2 with CS2 leads to the formation of novel trinuclear rare-earth metal thione dianion clusters, for which a possible pathway was determined by DFT calculation. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Progress on Study of Luminescence of Rare Earth Organic Chelates

    杨燕生; 安保礼; 龚孟濂; 史华红; 雷衡毅; 孟建新


    Based on the investigation of the luminescence of a series of rare earth organic chelates, some relationships between luminescence and the structure of the chelates were proposed: the intensity of sensitized luminescence of central lanthanide ions(Ln3+) in a rare earth organic chelate depends on (1)the suitability of the energy gap between the excited triplet energy level of the ligands and the lowest excited energy level of Ln3+ ions; (2)the rigidity and planarity of the structure of the chelate molecule; (3)the existence of a suitable secondary ligand which may increase rigidity and the stability of the chelate molecule; and (4) the existence of a suitable π-conjugated system in the chelate molecule. According to the above relationships, 25 novel organic ligands were designed and synthesized, and their lanthanide chelates were prepared. Investigation of the photoluminescence for the new chelates shows that some of the chelates are strongly luminescent, and are applied to fluoroimmunoassay for determination of human immunoglobulin(IgG), to preparation of fluorescent plastics, and to determination of growth hormone for plants. Two novel spectroscopy-probe techniques for structure of coordination compounds and biological molecules were proposed and developed based on vibronic spectroscopy of Tb3+ complexes and fluorescence of Ce3+.

  9. Magnetic alignment study of rare-earth-containing liquid crystals.

    Galyametdinov, Yury G; Haase, Wolfgang; Goderis, Bart; Moors, Dries; Driesen, Kris; Van Deun, Rik; Binnemans, Koen


    The liquid-crystalline rare-earth complexes of the type [Ln(LH)3(DOS)3]-where Ln is Tb, Dy, Ho, Er, Tm, or Yb; LH is the Schiff base N-octadecyl-4-tetradecyloxysalicylaldimine; and DOS is dodecylsulfate-exhibit a smectic A phase. Because of the presence of rare-earth ions with a large magnetic anisotropy, the smectic A phase of these liquid crystals can be easier aligned in an external magnetic field than smectic A phases of conventional liquid crystals. The magnetic anisotropy of the [Ln(LH)3(DOS)3] complexes was determined by measurement of the temperature-dependence of the magnetic susceptibility using a Faraday balance. The highest value for the magnetic anisotropy was found for the dysprosium(III) complex. The magnetic alignment of these liquid crystals was studied by time-resolved synchrotron small-angle X-ray scattering experiments. Depending on the sign of the magnetic anisotropy, the director of the liquid-crystalline molecules was aligned parallel or perpendicular to the magnetic field lines. A positive value of the magnetic anisotropy (and parallel alignment) was found for the thulium(III) and the ytterbium(III) complexes, whereas a negative value of the magnetic anisotropy (and perpendicular alignment) was observed for the terbium(III) and dysprosium(III) complexes.


    Fujita, Y.; Barnes, J.; Fox, S.


    Increasing demand for rare earth elements (REE) is expected to lead to new development and expansion in industries processing and or recycling REE. For some industrial operators, sending aqueous waste streams to a municipal wastewater treatment plant, or publicly owned treatment works (POTW), may be a cost effective disposal option. However, wastewaters that adversely affect the performance of biological wastewater treatment at the POTW will not be accepted. The objective of our research is to assess the effects of wastewaters that might be generated by new rare earth element (REE) beneficiation or recycling processes on biological wastewater treatment systems. We have been investigating the impact of yttrium and europium on the biological activity of activated sludge collected from an operating municipal wastewater treatment plant. We have also examined the effect of an organic complexant that is commonly used in REE extraction and separations; similar compounds may be a component of newly developed REE recycling processes. Our preliminary results indicate that in the presence of Eu, respiration rates for the activated sludge decrease relative to the no-Eu controls, at Eu concentrations ranging from <10 to 660 µM. Yttrium appears to inhibit respiration as well, although negative impacts have been observed only at the highest Y amendment level tested (660 µM). The organic complexant appears to have a negative impact on activated sludge activity as well, although results are variable. Ultimately the intent of this research is to help REE industries to develop environmentally friendly and economically sustainable beneficiation and recycling processes.

  11. Leaching hydrodynamics of weathered elution-deposited rare earth ore


    Both porosity (φ) and permeability (k) of the weathered elution-deposited rare earth ores are basic hydrodynamic parameters for RE leaching. The relationship between k and φ of two typical rare earth ores of South China in the packed bed was investigated by measuring the flow (Q) under various leaching pressure difference (Δp). The experimental results show that the relationship between k and φ is unique, moreover the relationship between Q and Δp is in accord with the Darcy's law. The effects of the type of ores, the leaching reagents and its concentration, the granule ore size on the leaching permeability have also been investigated. It is demonstrated that kH (for heavy RE ore, kH=35.98 mm2)>kM-H (for middle-heavy RE ore,kM-H=28.50 mm2), whereas k(NH4NO3)>k(NH4Cl)>k[(NH4)2SO4], and the k value increases with increasing leaching reagents concentration and granule ore size(k0.60~0.75 mm=99.96 mm2,k0.125~0.60 mm=11.83 mm2, k0.074~0.125 mm=0.84 mm2).

  12. Magnetic and Magnetoelectric Properties of Rare Earth Molybdates

    B. K. Ponomarev


    Full Text Available We present results on ferroelectric, magnetic, magneto-optical properties and magnetoelectric effect of rare earth molybdates (gadolinium molybdate, GMO, and terbium molybdate, TMO, and samarium molybdate, SMO, belonging to a new type of ferroelectrics predicted by Levanyuk and Sannikov. While cooling the tetragonal β-phase becomes unstable with respect to two degenerate modes of lattice vibrations. The β-β′ transition is induced by this instability. The spontaneous polarization appears as a by-product of the lattice transformation. The electric order in TMO is of antiferroelectric type. Ferroelectric and ferroelastic GMO and TMO at room temperature are paramagnets. At low temperatures GMO and TMO are antiferromagnetic with the Neel temperatures TN=0.3 K (GMO and TN=0.45 K (TMO. TMO shows the spontaneous destruction at 40 kOe magnetic field. Temperature and field dependences of the magnetization in TMO are well described by the magnetism theory of singlets at 4.2 K ≤ T ≤ 30 K. The magnetoelectric effect in SMO, GMO and TMO, the anisotropy of magnetoelectric effect in TMO at T = (1.8–4.2 K, the Zeeman effect in TMO, the inversion of the electric polarization induced by the laser beam are discussed. The correlation between the magnetic moment of rare earth ion and the magnetoelectric effect value is predicted. The giant fluctuations of the acoustic resonance peak intensity near the Curie point are observed.

  13. New approaches for rare earth-magnesium based hydrogen storage alloys

    Huaiwei Zhang


    Full Text Available As the most possibility applied to the next generation negative electrode materials of Ni/ MH second battery, rare earth (RE-magnesium (Mg based alloys have been developed over the last few years. Recent advances about the RE-Mg based intermetallic compounds on the crystal structures, hydrogenation behaviors and electrochemical performances are reviewed in the paper. On the other hand, new results about the preparation and modification methods of the alloys are also covered in details.



    Force Base, Dayton OH, March 20th 2013 23. Informatics Aided Discovery of Energy Materials 2013 Kentucky Workshop on Renewable Energy and Energy ...AFRL-AFOSR-VA-TR-2016-0122 Sustainable Alloy Design Searching for Rare Earth Element Alternatives through Crystal Engineering Krishna Rajan IOWA...reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching

  15. NIR persistent luminescence of lanthanide ion-doped rare-earth oxycarbonates: the effect of dopants.

    Caratto, Valentina; Locardi, Federico; Costa, Giorgio Andrea; Masini, Roberto; Fasoli, Mauro; Panzeri, Laura; Martini, Marco; Bottinelli, Emanuela; Gianotti, Enrica; Miletto, Ivana


    A series of luminescent rare-earth ion-doped hexagonal II-type Gd oxycarbonate phosphors Gd2-xRExO2CO3 (RE = Eu(3+), Yb(3+), Dy(3+)) have been successfully synthesized by thermal decomposition of the corresponding mixed oxalates. The Yb(3+) doped Gd-oxycarbonate has evidenced a high persistent luminescence in the NIR region, that is independent from the temperature and makes this materials particular attractive as optical probes for bioimaging.

  16. TEM Analysis of Rare Earth Dopant Distribution in YAG Optical Ceramics


    The research activity on advanced optical materials for various applications, such as lasers, scintillators, phosphors, is greatly increasing with the availability of sintered polycrystalline ceramics, which present some advantages compared to single crystals (sizes, mechanical strength, overall production cost). Understanding their optical properties requires a detailed investigation of their microstructure, especially regarding the exact location of the required dopants (e.g. rare earth ele...

  17. China’s Rare Earths Production Forecasting and Sustainable Development Policy Implications

    Xibo Wang


    Full Text Available Because of their unique physical and chemical properties, Rare earth elements (REEs perform important functions in our everyday lives, with use in a range of products. Recently, the study of China’s rare earth elements production has become a hot topic of worldwide interest, because of its dominant position in global rare earth elements supply, and an increasing demand for rare earth elements due to the constant use of rare earth elements in high-tech manufacturing industries. At the same time, as an exhaustible resource, the sustainable development of rare earth elements has received extensive attention. However, most of the study results are based on a qualitative analysis of rare earth elements distribution and production capacity, with few studies using quantitative modeling. To achieve reliable results with more factors being taken into consideration, this paper applies the generic multivariant system dynamics model to forecast China’s rare earth elements production trend and Hubbert peak, using Vensim software based on the Hubbert model. The results show that the peak of China’s rare earth elements production will appear by 2040, and that production will slowly decline afterwards. Based on the results, the paper proposes some policy recommendations for the sustainable development of China’s—and the world’s—rare earth elements market and rare earth-related industries.

  18. Synthesis of rare earth sulfides and their UV-vis absorption spectra

    YUAN Haibin; ZHANG Jianhui; YU Ruijin; SU Qiang


    Rare earth sulfides were systematically synthesized via the sulfurization of their commercial oxide powders using CS2 gas to shorten sulfurization time, and their UV-vis absorption spectra were investigated. The appropriate sulfurization conditions were studied. For the rare earth sulfides with the same crystal structure, the sulfurization temperature showed increasing tendency with the decrease of rare earth element atomic radii. The UV-vis absorption spectra of rare earth sulfides did not depend on the crystal structure of rare earth sulfides, but on the 4f electronic structure of rare earth element. The data showed that the optical band gaps of rare earth sulfides were irregular, and the values ranged from 1.65 to 3.75 eV.

  19. Value analysis of neodymium content in shredder feed: toward enabling the feasibility of rare earth magnet recycling.

    Bandara, H M Dhammika; Darcy, Julia W; Apelian, Diran; Emmert, Marion H


    In order to facilitate the development of recycling technologies for rare earth magnets from postconsumer products, we present herein an analysis of the neodymium (Nd) content in shredder scrap. This waste stream has been chosen on the basis of current business practices for the recycling of steel, aluminum, and copper from cars and household appliances, which contain significant amounts of rare earth magnets. Using approximations based on literature data, we have calculated the average Nd content in the ferrous shredder product stream to be between 0.13 and 0.29 kg per ton of ferrous scrap. A value analysis considering rare earth metal prices between 2002 and 2013 provides values between $1.32 and $145 per ton of ferrous scrap for this material, if recoverable as pure Nd metal. Furthermore, we present an analysis of the content and value of other rare earths (Pr, Dy, Tb).

  20. Recovery of rare earth elements from El-Sela effluent solutions

    Y.M. Khawassek


    Full Text Available The study area of Gabal El Sela at Halaib environ is located at about 20 km west of Abu Ramad City, Egypt. An uraniferous ore material associated with REE was subjected to sulphuric acid leaching for the extraction of uranium mainly and REEs as a by-product. 93.9% of U and 60% of REEs content were leached using −0.5 mm ground ore with 100 g/l sulfuric acid, acid/ore ratio of 2.0 and agitate for 6 h at 40 °C. After uranium extraction, effluent solutions containing 135 ppm rare earths were treated with 30% ammonium hydroxide to pH of 9.3 to enhance the rare earth elements concentration. The precipitated cake was filtered then dried at 110 °C. The dried cake containing 16.2% rare earth elements was dissolved by hydrochloric acid at pH 1.0. The rare earths precipitated cakes of 36.9, 45.7 and 48.7% REEs were recovered successfully from the chloride leach liquor of 900 ppm rare earths by using 5% v/v from 50% HF, 6% wt/v oxalic acid and 4.8% wt/v oxalic acid to chloride solution with heating for one hour which respectively. 73.5% REEs precipitated cake was achieved by double precipitation, firstly by hydrofluoric acid followed by oxalic acid precipitation.

  1. Rare earth metals in North America; Zeldzame aardmetalen in Noord-Amerika

    Louzada, K.


    The uncertain supply of rare earth metals (Rare Earth Elements) from China for the high tech industry in the U.S. is a barrier for innovation and the high-tech manufacturing industry. Many rare earths are applied in permanent magnets for sustainable energy generation and for energy storage systems in for example electric cars. Also other sectors feel the pressure of shortages. The federal government in the USA and US companies use the opportunity to encourage research into recycling, reducing the use and finding alternatives for rare earths. Canada sees in the uncertain supply and dwindling reserves in the USA and elsewhere an economic opportunity. Canada can start the development of hitherto unprofitable reserves of valuable materials. Both in the USA and Canada, the number of exploration projects in the mining industry has grown significantly [Dutch] De onzekere aanvoer van zeldzame aardmetalen (Rare Earth Elements) uit China voor de hightechindustrie vormt in de VS een hindernis voor innovatie en voor de hightech maakindustrie. Met name in permanente magneten voor duurzame energieopwekking en energieopslagsystemen voor bijvoorbeeld elektrische auto's worden veel zeldzame aardmetalen verwerkt. Ook andere sectoren staan onder druk. De federale overheid en bedrijven in de VS maken van de gelegenheid gebruik om onderzoek naar de recycling, vermindering van het gebruik en alternatieven voor zeldzame aardmetalen te stimuleren. Canada ziet de onzekere aanvoer en slinkende reserves in de VS en elders als een economische kans. Het land kan tot nu toe onrendabele voorkomens van de waardevolle materialen gaan ontwikkelen. Zowel in de VS als in Canada is het aantal exploratieprojecten in de mijnbouw aanzienlijk gegroeid.

  2. Standard model of the rare earths analyzed from the Hubbard I approximation

    Locht, I. L. M.; Kvashnin, Y. O.; Rodrigues, D. C. M.; Pereiro, M.; Bergman, A.; Bergqvist, L.; Lichtenstein, A. I.; Katsnelson, M. I.; Delin, A.; Klautau, A. B.; Johansson, B.; Di Marco, I.; Eriksson, O.


    In this work we examine critically the electronic structure of the rare-earth elements by use of the so-called Hubbard I approximation. From the theoretical side all measured features of both occupied and unoccupied states are reproduced, without significant deviations between observations and theory. We also examine cohesive properties like the equilibrium volume and bulk modulus, where we find, in general, a good agreement between theory and measurements. In addition, we have reproduced the spin and orbital moments of these elements as they are reflected from measurements of the saturation moment. We have also employed the Hubbard I approximation to extract the interatomic exchange parameters of an effective spin Hamiltonian for the heavy rare earths. We show that the Hubbard I approximation gives results which are consistent with calculations where 4 f electrons are treated as core states for Gd. The latter approach was also used to address the series of the heavy/late rare earths. Via Monte Carlo simulations we obtained ordering temperatures which reproduce measurements within about 20 % . We have further illustrated the accuracy of these exchange parameters by comparing measured and calculated magnetic configurations for the heavy rare earths and the magnon dispersion for Gd. The Hubbard I approximation is compared to other theories of the electronic structure, and we argue that it is superior. We discuss the relevance of our results in general and how this makes it possible to treat the electronic structure of materials containing rare-earth elements, such as permanent magnets, magnetostrictive compounds, photovoltaics, optical fibers, topological insulators, and molecular magnets.

  3. Recycling of the rare earth oxides from spent rechargeable batteries using waste metallurgical slags

    Tang K.


    Full Text Available A high temperature process for recycling spent nickel-metal hydride rechargeable batteries has been recently developed at SINTEF/NTNU. The spent battery modules were first frozen with liquid nitrogen for the de-activation and brittle fracture treatment. The broken steel scraps and plastics were then separated by the mechanical classification and magnetic separation. The remaining positive and negative electrodes, together with the polymer separator, were heated to 600-800oC in order to remove the organic components and further separate the Ni-based negative electrode. XRF analyses indicate that the heat-treated materials consist mainly of nickel, rare earth and cobalt oxides. The valuable rare earth oxides were further recovered by the high-temperature slagging treatment. The waste metallurgical slags, consist mainly of SiO2 and CaO, were used as the rare earth oxide absorbent. After the high temperature slagging treatment, over 98% of nickel and cobalt oxides were reduced to the metal phase; meanwhile almost all rare earth oxides remain in the molten slags. Furthermore, EPMA and XRF analyses of the slag samples indicate that the rare earth oxides selectively precipitate in the forms of solid xSiO2•yCaO•zRe2O3. The matrix of slag phase is Re2O3 deficient, typically being less than 5 wt%. This provides a sound basis to further develop the high-temperature process of concentrating the Re2O3 oxides in slags.

  4. Chinalco Guangxi Rare Earth Signed Strategic Cooperation Agreement with Yulin City


    <正>On June 18,Chinalco Guangxi Nonferrous&Rare Earth Development Co.,Ltd("Chinalco Guangxi Rare Earth")signed"Strategic Cooperation Agreement"with Yulin People’s Government,signifying that Guangxi rare earth resource and industry integration development led by Chinalco had made a key step forward.Sun zhaoxue,General Manager of Chinalco,Ding Haiyan,Assistant to General Manager of Chinalco and President of China Rare Metals

  5. Rare earth minerals and resources in the world

    Kanazawa, Yasuo [Human Resource Department, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba 305-8568 (Japan)]. E-mail:; Kamitani, Masaharu [Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8567 (Japan)


    About 200 rare earth (RE) minerals are distributed in a wide variety of mineral classes, such as halides, carbonates, oxides, phosphates, silicates, etc. Due to the large ionic radii and trivalent oxidation state, RE ions in the minerals have large coordination numbers (c.n.) 6-10 by anions (O, F, OH). Light rare earth elements (LREEs) tend to occupy the larger sites of 8-10 c.n. and concentrate in carbonates and phosphates. On the other hand, heavy rare earth elements (HREEs) and Y occupy 6-8 c.n. sites and are abundant in oxides and a part of phosphates. Only a few mineral species, such as bastnaesite (Ce,La)(CO{sub 3})F, monazite (Ce,La)PO{sub 4}, xenotime YPO{sub 4}, and RE-bearing clay have been recovered for commercial production. Bayan Obo, China is the biggest RE deposit in the world. One of probable hypotheses for ore geneses is that the deposit might be formed by hydrothermal replacement of carbonate rocks of sedimentary origin. The hydrothermal fluid may be derived from an alkaline-carbonatite intrusive series. Following Bayan Obo, more than 550 carbonatite/alkaline complex rocks constitute the majority of the world RE resources. The distribution is restricted to interior and marginal regions of continents, especially Precambrian cratons and shields, or related to large-scale rift structures. Main concentrated areas of the complexes are East African rift zones, northern Scandinavia-Kola peninsula, eastern Canada and southern Brazil. Representative sedimentary deposits of REE are placer- and conglomerate-types. The major potential countries are Australia, India, Brazil, and Malaysia. Weathered residual deposits have been formed under tropical and sub-tropical climates. Bauxite and laterite nickel deposit are the representative. Ion adsorption clay without radioactive elements is known in southern China. Weathering processes concentrate REE in a particular clay mineral-layer in the weathered crusts whose source were originally REE-rich rocks like granite

  6. Rare earth and zinc layered hydroxide salts intercalated with the 2-aminobenzoate anion as organic luminescent sensitizer

    Cursino, Ana Cristina Trindade, E-mail: [CEPESQ – Research Centre of Applied Chemistry, Department of Chemistry, Universidade Federal do Paraná – P.O. Box 19081, 81531-980 Curitiba, PR (Brazil); Rives, Vicente, E-mail: [GIR-QUESCAT – Department of Inorganic Chemistry, Universidad de Salamanca, Plaza de la Merced S/N, 37998 Salamanca (Spain); Arizaga, Gregorio Guadalupe Carbajal, E-mail: [Universidad de Guadalajara, Department of Chemistry, Boulevard Marcelino García Barragán 1421, C.P. 44430 Guadalajara, Jalisco (Mexico); Trujillano, Raquel, E-mail: [GIR-QUESCAT – Department of Inorganic Chemistry, Universidad de Salamanca, Plaza de la Merced S/N, 37998 Salamanca (Spain); Wypych, Fernando, E-mail: [CEPESQ – Research Centre of Applied Chemistry, Department of Chemistry, Universidade Federal do Paraná – P.O. Box 19081, 81531-980 Curitiba, PR (Brazil)


    Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The UV absorption ability was improved after intercalation/grafting in relation to that shown by the parent material. - Highlights: • Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide were synthesized. • Intercalated nitrate anions were exchanged by 2-aminobenzoate. • In all the 2-aminobenzoate containing compounds, the grafting reaction was detected. • The UV absorption ability was improved after the exchange reactions. • Rare earth hydroxide salts are potential matrixes to produce luminescent materials. - Abstract: Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The obtained compounds were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and ultraviolet visible (UV–vis) spectroscopies, fluorescence measurements and thermal analysis (TGA/DTA). The results from FTIR spectroscopy suggest a direct coordination of 2-aminobenzoate to the metal cations of the inorganic layered structure. The organic derivative products from the intercalation reactions absorb a broader range of UV-light in relation to that shown by the parent material; the photoluminescence measurements present a strong violet, blue and green luminescence under UV-light excitation for layered compounds with, Zn, Y and Tb, respectively. Rare earth hydroxide salts (RE-LHS) are potential alternative matrices for the immobilization of organic species to produce luminescent materials.

  7. A review of fractionations of rare earth elements in plants

    LIANG Tao; DING Shiming; SONG Wenchong; CHONG Zhongyi; ZHANG Chaosheng; LI Haitao


    Studies were carried out on several aspects of rare earth elements (REEs), such as the theory and practice of their applications in agriculture, their geochemical behaviors in natural and agricultural ecosystems, the mechanisms for the increase of crop yield using REE fertilizer, and their toxicology. However, limited knowledge was available for the transfer processes and the features and mechanisms of distribution and fractionatious of REEs inside plants. The characteristics of REE fractionations in plants can be used to "trace" the pathway of REE transportation from soils (solution) to plants. A better understanding of the mechanisms of REE fractionations was helpful to investigate the controlling factors, including both the internal and the external ones. The characteristics and mechanisms of REE fractionatious in plants and their significance were reviewed. Furthermore, the prospect for these fields was discussed, in hope of providing a new way in studying the bioavailability of REEs and heavy metals.

  8. Coordination field analysis of rare earth complexes with triangular symmetry

    范英芳; 潘大丰; 杨频


    The calculation of the complex matrixes in odd triangular symmetry was accomplished.The configurations of the coordination unit with various triangular symmetries and different ligand numbers were discussed.On the basis of the double-sphere coordination point-charge (DSCPCF) model,the detailed forms of the DSCPCF parameters Bmk and the expressions of the perturbation matrix elements in triangular field (D3,D3h,D3d) were derived.Thereby,the calculation scheme of coordination field perturbation energy of the rare earth complexes with triangular symmetry was constructed After the calculation scheme was programmed,the Stark energies of the crystalline TbAl3(BO3)4 were calculated The results were considerably close to the experimental values

  9. Coupled-channel optical model potential for rare earth nuclei

    Herman, M; Palumbo, A; Dietrich, F S; Brown, D; Hoblit, S


    Inspired by the recent work by Dietrich et al., substantiating validity of the adiabatic assumption in coupled-channel calculations, we explore the possibility of generalizing a global spherical optical model potential (OMP) to make it usable in coupled-channel calculations on statically deformed nuclei. The generalization consists in adding the coupling of the ground state rotational band, deforming the potential by introducing appropriate quadrupole and hexadecupole deformation and correcting the OMP radius to preserve volume integral of the spherical OMP. We choose isotopes of three rare-earth elements (W, Ho, Gd), which are known to be nearly perfect rotors, to perform a consistent test of our conjecture on integrated cross sections as well as on angular distributions for elastic and inelastic neutron scattering. When doing this we employ the well-established Koning-Delaroche global spherical potential and experimentally determined deformations without any adjustments. We observe a dramatically improved a...

  10. Orthodontic rare earth magnets--in vitro assessment of cytotoxicity.

    Bondemark, L; Kurol, J; Wennberg, A


    The aim of this study was to assess and compare in vitro the cytotoxic effects of uncoated and parylene-coated rare earth magnets, used in orthodontics. Cytotoxicity of samarium-cobalt magnets (SmCo5 and Sm2Co17) and neodymium-iron-boron magnets (Nd2Fe14B) was assessed by two in vitro methods, the millipore filter method and an extraction method. Orthodontic stainless steel brackets served as controls. Uncoated SmCo5-magnets showed high cytotoxicity while uncoated Sm2Co17-magnets demonstrated moderate cytotoxicity. Uncoated neodymium-iron-boron magnets, as well as parylene coated Sm2Co17-magnets and parylene-coated neodymium-iron-boron magnets, showed negligible cytotoxicity. Short-term exposure to a static magnetic field did not cause any cytotoxic effect on the cells.

  11. Spectroscopic studies of Yb3+-doped rare earth orthosilicate crystals

    Campos, S.; Denoyer, A.; Jandl, S.; Viana, B.; Vivien, D.; Loiseau, P.; Ferrand, B.


    Infrared transmission and Raman scattering have been used to study Raman active phonons and crystal-field excitations in Yb3+-doped yttrium, lutetium and scandium orthosilicate crystals (Y2SiO5 (YSO), Lu2SiO5 (LSO) and Sc2SiO5 (SSO)), which belong to the same C2h6 crystallographic space group. Energy levels of the Yb3+ ion 2F5/2 manifold are presented. In the three hosts, Yb3+ ions experience high crystal field strength, particularly in Yb:SSO. Satellites in the infrared transmission spectra have been detected for the first time in the Yb3+-doped rare earth orthosilicates. They could be attributed to perturbed Yb3+ sites of the lattices or to magnetically coupled Yb3+ pairs.

  12. Supramolecular structures constructed from three novel rare earth metal complexes

    Huaze Dong; Xiaojun Feng; Xia Liu; BiN Zheng; Jianhong Bi; Yan Xue; Shaohua Gou; Yanping Wang


    Three rare earth metal supramolecular complexes, {[Tb(2)4](ClO4)3·2H2O(1), [Eu(2)2(H2O)5] (ClO4)3(2) and [Gd(NO3)3(2)2]·2CH3CH2OH(3) ( 2 = 3-Dimethylamino-1-pyridin-2-yl-propenone), have been synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. The crystal structure analysis reveals that the coordination numbers of three complexes (1–3) are 8, 9 and 10, respectively. Three complexes assembled into 3D frameworks based on C-H⋯O, O-H⋯O hydrogen bond linkages.

  13. Contents and distribution of rare earth elements in wheat seeds


    Contents of 15 rare earth elements (REEs) in the seeds of 60 breeds of wheat have been analyzed by the inductively-coupled plasma mass spectrometry (ICP-MS). The distribution pattern of contents of REEs in wheat seeds has been observed and compared with that in soils. Comparison with literature data has also been made. The results show that the background of REEs in wheat seeds is 10-11-10-8 g.g-1, 3-4 levels lower than in soils. The distribution pattern is light REEs higher in contents and slight Eu-anomaly, similar to that in soils. The data obtained in this study can accurately represent the background content of REEs in wheat seeds.

  14. Study on Adsorption of Rare Earth Elements by Kaolinite

    Wan Yingxin; Liu Congqiang


    For better understanding the adsorption of rare earth elements (REEs) by clay minerals and its controlling factors, the experiments on adsorption of REEs in solutions with 1 g·L-1 kaolinite were performed at different conditions. The results are as follows: the REEs reach equilibrium in the adsorption-desorption process for 24; Langmuir's adsorption curve is used for modeling the adsorption of REEs by kaolinite; a general trend is that the higher the contents of REEs are, the less obvious the fractionation is. Furthermore, there is significant effect of pH on the adsorption and fractionation of REEs by kaolinite, and the REEs distribution coefficient increases with increasing pH. When pH is nearly neutral, as reaches 7, heavy REEs are more adsorbed than light REEs.

  15. Rare Earth core/shell nanobarcodes for multiplexed trace biodetection.

    Chen, Lei; Li, Xiaomin; Shen, Dengke; Zhou, Lei; Zhu, Dan; Fan, Chunhai; Zhang, Fan


    Multiplexed detection technology has been attractive for its simultaneous assay of several analytes, which play significant roles in applications such as screening for combinatorial chemistry, genetic analysis, and clinical diagnostics. This work reports a novel and potentially powerful encoding system based upon dispersible suspension arrays of multilayer rare earth core/shell nanoparticles that are capable of multiplexed, high-sensitivity reporting for biomolecule detection by the Z-contrast imaging. These nanobarcode arrays are encoded by nanostructure design based on different atomic numbers. With the well-resolved high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) decoding technique, many thousands of unique nanobarcodes can be identified by multilayer core/shell nanostructure. Their applications to multiplexed biodetection of DNA demonstrated the highly sensitive (picomole) features of this novel nanobarcode system.

  16. Crystallization of mixed rare earth (didymium) molybdates in silica gel

    Sanjay Pandita; Ravender Tickoo; K K Bamzai; P N Kotru; Neera Sahni


    Experiments on the growth of mixed rare earth (didymium—a combination of La, Nd, Pr and Sm) molybdates in silica gel medium are reported. The optimum conditions conducive for the growth of these crystals are described and discussed. Concentration programming is reported to enhance the size of crystals by two-fold; the maximum size obtained being about 1 mm3. EDAX results suggest the crystals to be heptamolybdates of type R2Mo7O24, bearing composition La1.23Nd0.43Pr0.29 Sm0.05Mo7O24. The didymium molybdate crystals assume morphologies corresponding to those of spherulites, platelets, cuboids and coalesced crystals. Twinned structure in didymium molybdate crystals are also reported. It is explained that spherulitic morphologies result from aggregates of crystals joining in a spherical envelope. It is suggested that the crystals of didymium molybdates grow by two-dimensional spreading and piling up of layers.

  17. Attenuation of rare earth elements in a boreal estuary

    Åström, Mats E.; Österholm, Peter; Gustafsson, Jon Petter; Nystrand, Miriam; Peltola, Pasi; Nordmyr, Linda; Boman, Anton


    This study focuses on attenuation of rare earth elements (REE) when a boreal creek, acidified and loaded with REE and other metals as a result of wetland drainage, empties into a brackish-water estuary (salinity MINTEQ version 3.0 and the Stockholm Humic Model after revision and updating, predicted that the dissolved (<0.45 μm) REE pool in the estuary is bound almost entirely to humic substances. Acid sulphate soils, the source of the REE and other metals in the creek water, are widespread on coastal plains worldwide and therefore the REE attenuation patterns and mechanisms identified in the studied estuary are relevant for recognition of similar geochemical processes and conditions in a variety of coastal locations.

  18. Preparation and Characterization of Rare Earth Doped Fluoride Nanoparticles

    Timothy A. DeVol


    Full Text Available This paper reviews the synthesis, structure and applications of metal fluoride nanoparticles, with particular focus on rare earth (RE doped fluoride nanoparticles obtained by our research group. Nanoparticles were produced by precipitation methods using the ligand ammonium di-n-octadecyldithiophosphate (ADDP that allows the growth of shells around a core particle while simultaneously avoiding particle aggregation. Nanoparticles were characterized on their structure, morphology, and luminescent properties. We discuss the synthesis, properties, and application of heavy metal fluorides; specifically LaF3:RE and PbF2, and group IIA fluorides. Particular attention is given to the synthesis of core/shell nanoparticles, including selectively RE-doped LaF3/LaF3, and CaF2/CaF2 core/(multi-shell nanoparticles, and the CaF2-LaF3 system.

  19. Preparing Process of Cerium Acetate and Rare Earth Acetate

    Qiao Jun; Ma Ying; Xu Yanhui; Zhang Jun; Chang Shu; Hao Xianku


    Preparing process was presented and the influences of concentration of acetic acid, reaction temperature, the ratio of cerium carbonate and acetic acid, heat preservation time to the yield of cerium acetate were discussed.The crystalline cerium acetate and rare earth acetate such as ( La, Ce, Pr, Nd) (Ac) 3, ( Ce, Pr, Nd) (Ac) 3, ( Pr, Nd, Er,Y) (Ac) 3 and yttrium acetate were prepared under this condition.The shape, structure and composition of the crystals were determined by the methods of SEM, TG-DTA, X-ray diffraction and chemical analysis.The optimum prepared conditions of cerium acetate were described.This prepared process has characteristics such as simple process route, low cost, high yield, good quality, no pollution to environment, etc.

  20. Pressure-induced exotic states in rare earth hexaborides

    Sun, Liling; Wu, Qi


    Finding the exotic phenomena in strongly correlated electron systems (SCESs) and understanding the corresponding microphysics have long been the research frontiers of condensed matter physics. The remarkable examples for the intriguing phenomena discovered in past years include unconventional superconductivity, heavy Fermion behaviors, giant magneto-resistance and so on. A fascinating type of rare earth hexaboride RB6 (R  =  Sm, Yb, Eu and Ce) belongs to a strongly correlated electron system (SCES), but shows unusual ambient-pressure and high-pressure behaviors beyond the phenomena mentioned above. Particularly, the recent discovery of the coexistence of an unusual metallic surface state and an insulating bulk state in SmB6, known to be a Kondo insulator decades ago, by theoretical calculations and many experimental measurements creates new interest for the investigation of the RB6. This significant progress encourages people to revisit the RB6 with an attempt to establish a new physics that links the SCES and the unusual metallic surface state which is a common feature of a topological insulator (TI). It is well known that pressure has the capability of tuning the electronic structure and modifying the ground state of solids, or even inducing a quantum phase transition which is one of the kernel issues in studies of SCESs. In this brief review, we will describe the progress in high pressure studies on the RB6 based on our knowledge and research interests, mainly focusing on the pressure-induced phenomena in YbB6 and SmB6, especially on the quantum phase transitions and their connections with the valence state of the rare earth ions. Moreover, some related high-pressure results obtained from CeB6 and EuB6 are also included. Finally, a summary is given in the conclusions and perspectives section.

  1. Rare earth activated yttrium aluminate phosphors with modulated luminescence.

    Muresan, L E; Popovici, E J; Perhaita, I; Indrea, E; Oro, J; Casan Pastor, N


    Yttrium aluminate (Y3 A5 O12 ) was doped with different rare earth ions (i.e. Gd(3+) , Ce(3+) , Eu(3+) and/or Tb(3+) ) in order to obtain phosphors (YAG:RE) with general formula,Y3-x-a Gdx REa Al5 O12 (x = 0; 1.485; 2.97 and a = 0.03). The synthesis of the phosphor samples was done using the simultaneous addition of reagents technique. This study reveals new aspects regarding the influence of different activator ions on the morpho-structural and luminescent characteristics of garnet type phosphor. All YAG:RE phosphors are well crystallized powders containing a cubic-Y3 Al5 O12 phase as major component along with monoclinic-Y4 Al2 O9 and orthorhombic-YAlO3 phases as the impurity. The crystallites dimensions of YAG:RE phosphors vary between 38 nm and 88 nm, while the unit cell slowly increase as the ionic radius of the activator increases. Under UV excitation, YAG:Ce exhibits yellow emission due to electron transition in Ce(3+) from the 5d level to the ground state levels ((2) F5/2 , (2) F7/2 ). The emission intensity of Ce(3+) is enhanced in the presence of the Tb(3+) ions and is decreased in the presence of Eu(3+) ions due to some radiative or non-radiative processes that take place between activator ions. By varying the rare earth ions, the emission colour can be modulated from green to white and red. Copyright © 2015 John Wiley & Sons, Ltd.

  2. Pressure-induced exotic states in rare earth hexaborides.

    Sun, Liling; Wu, Qi


    Finding the exotic phenomena in strongly correlated electron systems (SCESs) and understanding the corresponding microphysics have long been the research frontiers of condensed matter physics. The remarkable examples for the intriguing phenomena discovered in past years include unconventional superconductivity, heavy Fermion behaviors, giant magneto-resistance and so on. A fascinating type of rare earth hexaboride RB6 (R  =  Sm, Yb, Eu and Ce) belongs to a strongly correlated electron system (SCES), but shows unusual ambient-pressure and high-pressure behaviors beyond the phenomena mentioned above. Particularly, the recent discovery of the coexistence of an unusual metallic surface state and an insulating bulk state in SmB6, known to be a Kondo insulator decades ago, by theoretical calculations and many experimental measurements creates new interest for the investigation of the RB6. This significant progress encourages people to revisit the RB6 with an attempt to establish a new physics that links the SCES and the unusual metallic surface state which is a common feature of a topological insulator (TI). It is well known that pressure has the capability of tuning the electronic structure and modifying the ground state of solids, or even inducing a quantum phase transition which is one of the kernel issues in studies of SCESs. In this brief review, we will describe the progress in high pressure studies on the RB6 based on our knowledge and research interests, mainly focusing on the pressure-induced phenomena in YbB6 and SmB6, especially on the quantum phase transitions and their connections with the valence state of the rare earth ions. Moreover, some related high-pressure results obtained from CeB6 and EuB6 are also included. Finally, a summary is given in the conclusions and perspectives section.

  3. Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

    Martin, Madhavi Z [ORNL; Fox, Dr. Richard V [Idaho National Laboratory (INL); Miziolek, Andrzej W [United States Army Research Laboratory; DeLucia, Frank C [United States Army Research Laboratory; Andre, Nicolas O [ORNL


    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in real-world complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  4. Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

    Martin, Madhavi Z [ORNL; Fox, Dr. Richard V [Idaho National Laboratory (INL); Miziolek, Andrzej W [United States Army Research Laboratory; DeLucia, Frank C [United States Army Research Laboratory; Andre, Nicolas O [ORNL


    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in realworld complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  5. Application of response surface methodology for optimization of parameters for microwave heating of rare earth carbonates

    Yin, Shaohua; Lin, Guo; Li, Shiwei; Peng, Jinhui; Zhang, Libo


    Microwave heating has been applied in the field of drying rare earth carbonates to improve drying efficiency and reduce energy consumption. The effects of power density, material thickness and drying time on the weight reduction (WR) are studied using response surface methodology (RSM). The results show that RSM is feasible to describe the relationship between the independent variables and weight reduction. Based on the analysis of variance (ANOVA), the model is in accordance with the experimental data. The optimum experiment conditions are power density 6 w/g, material thickness 15 mm and drying time 15 min, resulting in an experimental weight reduction of 73%. Comparative experiments show that microwave drying has the advantages of rapid dehydration and energy conservation. Particle analysis shows that the size distribution of rare earth carbonates after microwave drying is more even than those in an oven. Based on these findings, microwave heating technology has an important meaning to energy-saving and improvement of production efficiency for rare earth smelting enterprises and is a green heating process.

  6. Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

    Madhavi Z. Martin; Robert V. Fox; Andrzej W. Miziolek; Frank C. DeLucia, Jr.; Nicolas Andre


    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in realworld complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  7. Effects of Rare Earth Elements on Photocatalytic Antibacterial Properties of Nanometer TiO2 Powders

    Gao Ning; Liang Jinsheng; Meng Junping; Ou Xiuqin


    Nanometer Ce/TiO2 functional materials with photocatalystic antibacterial properties were prepared by dipping TiO2 nanometer powders into RE( NO3 )·nH2O solutions, filtrating, drying and heat treatment, and the enhancement mechanisms of Ce on the nanometer TiO2 were studied by electronic spin resonance(ESR) The results show that TiO2 for photocatalystic antibacterial properties is strengthened evidently by adding Ce, which has a high efficiency of photocatalystic antibacterial properties with the light extent of visible light and ultraviolet radiation. The basic reason for obtaining the strengthened result is that the effective wave length of photocatalystic properties of TiO2 can be expanded to visible light area with the induction of the rare earth elements, whether or not ultraviolet light exists, nanometer TiO2 can produce a great deal of hydroxylic radical(·OH) by treating with rare earth elements.

  8. X-ray resonant exchange scattering of rare-earth nickel borocarbides

    Detlefs, C.


    The purpose of this thesis is to investigate the systematics of the microscopic magnetic order within a series of isostructural compounds and, at the same, to develop the relatively young experimental method of x-ray resonant exchange scattering (XRES). In this thesis, the author presents XRES studies of several rare-earth nickel borocarbides, RNi{sub 2}B{sub 2}C. He shows that XRES, similar to the neutron techniques, allows the determination of the orientation of the magnetic moment by measuring the Q-dependence of the scattered intensity of magnetic Bragg reflections. As samples in this study, he chose the recently discovered family of rare-earth nickel borocarbides, RNi{sub 2}B{sub 2}C, which display a wide variety of magnetic structures. Furthermore, in several of these materials, long range magnetic order coexists with superconductivity over some temperature range.

  9. Fluorescence line-narrowing studies of rare earths in disordered solids

    Hall, D.W.


    This dissertation is made up of two experimental studies dealing with apparently diverse topics within the subject of rare earths (RE) in solids. The first study, described in Part II, concerns the vibrations of a disordered host material about an optically active rare-earth ion as manifested by vibrationally-assisted-electronic, or vibronic transitions. Part III of the dissertation describes an investigation of the influence of site anisotropy on the purely electronic, laser transition of Nd/sup 3 +/ in glass. These two studies are bound together by the common experimental technique of laser-induced fluorescence line narrowing (FLN). By exciting fluorescence with monochromatic light of well-characterized polarization, one may select and observe the response of a single subset of the optically active ions and obtain information that is usually masked by the inhomogeneous nature of disordered solids.

  10. Global demand for rare earth resources and strategies for green mining.

    Dutta, Tanushree; Kim, Ki-Hyun; Uchimiya, Minori; Kwon, Eilhann E; Jeon, Byong-Hun; Deep, Akash; Yun, Seong-Taek


    Rare earth elements (REEs) are essential raw materials for emerging renewable energy resources and 'smart' electronic devices. Global REE demand is slated to grow at an annual rate of 5% by 2020. This high growth rate will require a steady supply base of REEs in the long run. At present, China is responsible for 85% of global rare earth oxide (REO) production. To overcome this monopolistic supply situation, new strategies and investments are necessary to satisfy domestic supply demands. Concurrently, environmental, economic, and social problems arising from REE mining must be addressed. There is an urgent need to develop efficient REE recycling techniques from end-of-life products, technologies to minimize the amount of REEs required per unit device, and methods to recover them from fly ash or fossil fuel-burning wastes.

  11. Fabrication and Luminescence of Rare Earth Complex/SiO2 Hybrid Nanospheres

    赵丹; 秦伟平; 吴长锋; 张继森; 秦冠仕; 林海燕


    The organic rare earth complex was embedded in silica spheres to form inorganic-organic hybrid. Photoactive rare earth complexes with various organic ligands exhibit intense narrow emission band, and the silica is an excellent matrix for inorganic-organic structure. The transmission electron microscope image presents the hybrid nanospheres. The diameter of the hybrid is about 100 nm. The europium complex that incorporated into silica sphere is also proved by the IR spectra, the excitation and emission spectra. The lifetimes of the Eu3+ ions in the hybrid nanospheres and in the pure europium complex were also detected. This hybrid with inhomogeneous compositions exhibits specifically tailored chemical and optical properties, such as perfect thermal and mechanical stability, colorimetric purity and so on. It can be used as luminescent and optical material in EL and PL fields.

  12. Effect of Rare Earths on Mechanical Properties and Microstructures of Si3N4-based Ceramics


    The effects of Y2O3, La2O3 and Nd2O3 on the mechanical properties and microstructures of Si3N4-based ceramics were studied. It shows that a significant improvement in mechanical properties can be obtained by adding rare earths oxides in Si3N4. The fracture toughness and the flexural strength of Si3N4 added with both Y2O3 and La2O3 are 7.8 MPa.m1/2 and 962 MPa, respectively. The main reason is that adding rare earths in Si3N4 can improve the microstructure of the material and increase the aspect ratio of β-Si3N4 grain.

  13. Structural and crystal chemical properties of rare-earth titanate pyrochlores

    Farmer, James Matthew [ORNL; Boatner, Lynn A [ORNL; Chakoumakos, Bryan C [ORNL; Du, Mao-Hua [ORNL; Lance, Michael J [ORNL; Rawn, Claudia J. [Oak Ridge National Laboratory (ORNL); Bryan, Jeff C. [University of Wisconsin


    Rare-earth titanates, RE2Ti2O7 (where RE = a rare-earth) with the pyrochlore structure continue to be investigated for use as potential stable host materials for nuclear and actinide-rich wastes. Accordingly, the present work is directed towards the elucidation of the fundamental structural, physical, and thermochemical properties of this class of compounds. Single-crystals of the rare earth pyrochlores were synthesized using a high-temperature flux technique and were subsequently characterized using single-crystal X-ray diffraction. The cubic lattice parameters display an approximately linear correlation with the RE-site cation radius. Theoretical calculations of the lattice constants and bond lengths of the subject materials were carried out using density functional theory, and the results are compared to the experimental values. The Sm and Eu titanates exhibit a covalency increase between the REO8 and TiO6 polyhedra resulting in a deviation from the increasing linear lattice parameter through the transition series. Gd2Ti2O7 with the 4f7 half-filled f-orbital Gd3+ sub-shell exhibits the lowest 48f oxygen positional parameter. The coefficient of thermal expansion for the rare-earth titanate series is approximately linear, and it has a range of 10.1 11.2 x 10-6 C-1. Raman spectroscopy indicated that the ~530 cm-1 peak associated with the Ti-O stretching mode follows a general trend of decreasing frequency with increasing RE reduced mass.

  14. Characterization and Recovery of Rare Earths from Coal and By-Products

    Granite, Evan J. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Roth, Elliot [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Alvin, Mary Anne [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)


    Coal is a precious resource, both in the United States and around the world. The United States has a 250-year supply of coal, and generates between 30 - 40% of its electricity through coal combustion. Approximately 1 Gt of coal has been mined annually in the US, although the 2015 total will likely be closer to 900 Mt ( Most of the coal is burned for power generation, but substantial quantities are also employed in the manufacture of steel, chemicals, and activated carbons. Coal has a positive impact upon many industries, including mining, power, rail transportation, manufacturing, chemical, steel, activated carbon, and fuels. Everything that is in the earth’s crust is also present within coal to some extent, and the challenge is always to utilize abundant domestic coal in clean and environmentally friendly manners. In the case of the rare earths, these valuable and extraordinarily useful elements are present within the abundant coal and coal by-products produced domestically and world-wide. These materials include the coals, as well as the combustion by-products such as ashes, coal preparation wastes, gasification slags, and mining by-products. All of these materials can be viewed as potential sources of rare earth elements. Most of the common inorganic lanthanide compounds, such as the phosphates found in coal, have very high melting, boiling, and thermal decomposition temperatures, allowing them to concentrate in combustion and gasification by-products. Furthermore, rare earths have been found in interesting concentrations in the strata above and below certain coal seams. Much of the recent research on coal utilization in the United States has focused upon the capture of pollutants such as acid gases, particulates, and mercury, and the greenhouse gas carbon dioxide. The possible recovery of rare earth and other critical elements from abundant coal and by-products is an exciting new research area, representing a

  15. The effects of solidification and atomization on rare-earth alloys

    Anderson, Iver E.; Osborne, M. G.; Ellis, T. W.


    This article discusses the results of experiments involving the application of atomization techniques to the production of three selected rare-earth intermetallic (REI) materials. High-pressure gas atomization and centrifugal atomization into a rotating quench bath have been used to process the alloys. Rapid-solidification processing by atomization techniques is of great benefit since optimum performance of these REI materials demands chemical and structural homogeneity. The results demonstrate that such careful solidification microstructure control is required if the benefits of REI-alloy properties are to be realized with maximum processing efficiency.

  16. Magnetism of Rare-Earth Compounds with Non-Magnetic Crystal-Field Ground Levels

    LIU Zhao-Sen


    @@ Among rare-earth compounds, there are many materials having non-magnetic crystal-field (CF) ground levels.To understand their magnetic behaviour at low temperatures, we study the effects of the CF levels and the Heisenberg-like coupling on the magnetic process of such a crystalline with mean-field and CF theory. It is found that the material can be magnetically ordered if the Heisenberg exchange is sufficiently strong. Additionally we obtain a condition for initial magnetic ordering, and derive a formula for estimating the Curie temperature if the ordering occurs.


    E. P. Lisachenko


    Full Text Available Among the rare-earth metals with natural radioactive isotopes, lantan, lutetium and samarium are allocated a relatively high specific activity. The formation of the additional external radiation keep it close to the significance of the materials to the radiation categories of materials with a high content of natural radionuclides of uranium and thorium family, lanthanum value is much less. Samarium, with acceptable toxicology content in the working area, forms the internal exposure to the limits for professionals. The use of these elements in science and industry requires the radiation-hygienic evaluation.

  18. Development of Strip Casting Technology in Rare Earth Permanent Magnet Alloys and Hydrogen Storage Alloys in China

    Han Weiping; Guo Binglin; Yu Xiaojun; Zhu Jinghan; Cheng Xinghua


    The SC technique is now being applied widely in material preparation, especially in rare earth functional materials in virtue of its advanced process and high performance product. The applications of SC technique in rare earth permanent magnet alloys and hydrogen storage alloys were analyzed integrative, on the basis of summary of SC technique development in this paper. The paper mainly includes development history of SC technology, effect of SC technology on alloy microstructure, application of SC technology in RE storage hydrogen alloy and sintered Nd-Fe-B alloy, development of SC equipment and SC product industry. At the same time, the paper points out the existing problem of SC products.

  19. Situation and Developing Trend of Rare-Earth Countercurrent Extraction Processes Control

    柴天佑; 杨辉


    On the basis of the description of the rare-earth countercurrent extraction process, the on-line detecting method and equipments of rare-earth elements and the application in the process of the rare-earth countercurrent extraction are summarized. The procedure simulation of the computer, the automation control method and its current application are also mentioned in the process of rare-earth countercurrent extraction. The method of soft sensor is proposed. Optimal control method based on object-oriented rare-earth countercurrent extraction process and integrated automation system composed of process management system and process control system are presented, which are the developing direction of the automation of rare-earth countercurrent extraction process.

  20. History and Present Situation and Developing Tendency of Rare Earth Applied in Agriculture


    @@History of rare earth applied in agriculture Concept of rare earth Rare earth(RE for short)is a general designation of 17 elements,including 15 elements of lanthanum system,they are lanthanum (La),cerium (Ce),praseodymium (Pr),neodymium (Nd),promethium(Pm),samarium(Sm),europium(Eu),gadolinium(Gd),terbium(Tb),dysprosium(Dy),holmium(Ho),erbium(Er),thulium(Tm),ytterbium(Yb),lutetium(Lu)),and 2 elements of the same clan with lanthanum system: scandium (Se)and yttrium (Y) in the periodic table of elements.Rare earth look like earth or soil,and their quantity which may be separated from ore are very rare or few,so scientists call them rare earth elements.

  1. Comparative study of rare earth hexaborides using high resolution angle-resolved photoemission

    Ramankutty, S.V., E-mail: [Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Jong, N. de; Huang, Y.K.; Zwartsenberg, B. [Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Massee, F. [Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853 (United States); Bay, T.V. [Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Golden, M.S., E-mail: [Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Frantzeskakis, E., E-mail: [Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands)


    }(001) surface. All in all, our study highlights the suitability of electron spectroscopies like high-resolution ARPES to provide links between electronic structure and function in complex and correlated materials such as the rare earth hexaborides.

  2. Progress in rare-earth-doped nanocrystalline glass-ceramics for laser cooling

    Venkata Krishnaiah, Kummara; Ledemi, Yannick; Soares de Lima Filho, Elton; Loranger, Sebastien; Nemova, Galina; Messaddeq, Younes; Kashyap, Raman


    Laser cooling with anti-Stokes fluorescencewas predicted by Pringsheim in 1929, but for solids was only demonstrated in 1995. There are many difficulties which have hindered laser assisted cooling, principally the chemical purity of a sample and the availability of suitable hosts. Recent progress has seen the cooled temperature plummet to 93K in Yb:YLF. One of the challenges for laser cooling to become ubiquitous, is incorporating the rare-earthcooling ion in a more easily engineered material, rather than a pure crystalline host. Rare-earth-doped nanocrystalline glass-ceramics were first developed by Wang and Ohwaki for enhanced luminescence and mechanical properties compared to their parent glasses. Our work has focused on creating a nanocrystalline environment for the cooling ion, in an easy to engineer glass. The glasses with composition 30SiO2-15Al2O3-27CdF2-22PbF2-4YF3-2YbF3 (mol%), have been prepared by the conventional melt-quenching technique. By a simple post fabrication thermal treatment, the rare-earth ions are embedded in the crystalline phase within the glass matrix. Nanocrystals with various sizes and rare-earth concentrations have been fabricated and their photoluminescence properties assessed in detail. These materials show close to unity photoluminescence quantum yield (PLQY) when pumped above the band. However, they exhibit strong up-conversion into the blue, characteristic of Tm trace impurity whose presence was confirmed. The purification of the starting materials is underway to reduce the background loss to demonstrate laser cooling. Progress in the development of these nano-glass-ceramics and their experimental characterization will be discussed.

  3. The Application of High Performance Liquid Chromatography in the Analysis of Trace Rare Earth

    WANG; Xiu-feng; DING; You-qian


    <正>Rare earth elements are very important in the field of radioanalytical chemistry, for it must be separated and determined in the measurements of burn-up and fission yield. High performance liquid chromatography has become a main method in the separation of rare earth elements due to its obvious advantages, this is, high speed of analysis, high efficiency and easy automation. The ion exchange chromatography is the main means to separate rare earth elements, especially the cation exchange

  4. Preparation and Property of Acrylic Acid Rare Earth Complex and Its Hydrosilylation

    Zhang Ming; Chen Haiyan; Chen Xiaosong; Dai Shaojun; Inoue Shinich; Okamoto Hiroshi


    Acrylic acid rare earth complex was prepared. Its chemical composition was determined by chemical and elemental analysis, and its structure as well as properties was characterized using IR, Fluorescence and UV spectrum, and its solubility was also investigated. Meanwhile a kind of elastic functional polymer with rare earth units in the side chains was produced. It is confirmed by IR spectrum that the Si-H bonds really react with acrylic acid rare earth.

  5. Preparation and Mechanical Performance of Rare Earth-Containing Composite Elastomer

    邱关明; 周兰香; 张明; 中北里志; 井上真一; 冈本弘


    Rare earth-containing PSBR sheet was prepared by reaction of rare earth alkoxide with quaternary ammonium salt of pyridine modified SBR (PSBR) latex, and then it was blended with natural rubber (NR) to produce rare earth-containing composite elastomer. It is found that mechanical performance can be improved remarkably. Analyzed by infrared spectrometry (IR), differential scanning calorimetry (DSC) and cross-linking densitometry, the relationship between structure and performance was discussed.

  6. Methods for preparation of nanocrystalline rare earth phosphates for lighting applications

    Comanzo, Holly Ann; Manoharan, Mohan; Martins Loureiro, Sergio Paulo; Setlur, Anant Achyut; Srivastava, Alok Mani


    Disclosed here are methods for the preparation of optionally activated nanocrystalline rare earth phosphates. The optionally activated nanocrystalline rare earth phosphates may be used as one or more of quantum-splitting phosphor, visible-light emitting phosphor, vacuum-UV absorbing phosphor, and UV-emitting phosphor. Also disclosed herein are discharge lamps comprising the optionally activated nanocrystalline rare earth phosphates provided by these methods.

  7. Rare Earth Export Quota in the Second Half of 2008 Promulgated


    @@ On July the 4th of 2008, in accordance with "Commodities Import and Export Statute of the People's Republic of China", rare earth export quota for ordinary trade in the second half year of 2008 was promulgated by the Ministry of Commerce of P.R.C. Rare earth export quota in the second half of 2008 was distributed to those enterprises that were qualified for the application of rare earth export quota in 2008.

  8. Metal sulfide and rare-earth phosphate nanostructures and methods of making same

    Wong, Stanislaus; Zhang, Fen


    The present invention provides a method of producing a crystalline rare earth phosphate nanostructure. The method comprising: providing a rare earth metal precursor solution and providing a phosphate precursor solution; placing a porous membrane between the metal precursor solution and the phosphate precursor solution, wherein metal cations of the metal precursor solution and phosphate ions of the phosphate precursor solution react, thereby producing a crystalline rare earth metal phosphate nanostructure.

  9. Molecular rare-earth-metal hydrides in non-cyclopentadienyl environments.

    Fegler, Waldemar; Venugopal, Ajay; Kramer, Mathias; Okuda, Jun


    Molecular hydrides of the rare-earth metals play an important role as homogeneous catalysts and as counterparts of solid-state interstitial hydrides. Structurally well-characterized non-metallocene-type hydride complexes allow the study of elementary reactions that occur at rare-earth-metal centers and of catalytic reactions involving bonds between rare-earth metals and hydrides. In addition to neutral hydrides, cationic derivatives have now become available.

  10. Compositional Optimum Design and Experimental Investigation of Rare Earth Containing Ceramic Composite

    Xu Chonghai; Huang Chuanzhen; Ai Xing


    Based on the Al2O3/(W,Ti) C ceramic material, optimum design of the material compositions were carried out, which includes the theoretical calculation of the critical volume fraction of the reinforcement phase, and the optimum design based on the impact resistance, thermal shock resistance and wear resistance, etc. It is found that the optimum volume fraction of (W,Ti)C is 31.2%, 32.8% and 34%, respectively, which is corresponding with the best impact resistance, thermal shock resistance and wear resistance. After comprehensive consideration, the optimum volume fraction of (W,Ti)C in Al2O3/( W, Ti)C ceramic material is finally determined to be 30%. Then, effects of the content of rare earth yttrium on the mechanical property of the Al2O3/30vol% (W,Ti)C ceramic material were investigated experimentally. It indicates that when the content of yttrium is 0.25% ~ 0.5%, both flexural strength and fracture toughness of the rare earth containing ceramic material are further improved with the increment of approximately 10% ~16%.

  11. Combinatorial investigation of rare-earth free permanent magnets

    Fackler, Sean Wu

    The combinatorial high throughput method allows one to rapidly study a large number of samples with systematically changing parameters. We apply this method to study Fe-Co-V alloys as alternatives to rare-earth permanent magnets. Rare-earth permanent magnets derive their unmatched magnetic properties from the hybridization of Fe and Co with the f-orbitals of rare-earth elements, which have strong spin-orbit coupling. It is predicted that Fe and Co may also have strong hybridization with 4d and 5d refractory transition metals with strong spin-orbit coupling. Refractory transition metals like V also have the desirable property of high temperature stability, which is important for permanent magnet applications in traction motors. In this work, we focus on the role of crystal structure, composition, and secondary phases in the origin of competitive permanent magnetic properties of a particular Fe-Co-V alloy. Fe38Co52V10, compositions are known as Vicalloys. Fe-CoV composition spreads were sputtered onto three-inch silicon wafers and patterned into discrete sample pads forming a combinatorial library. We employed highthroughput screening methods using synchrotron X-rays, wavelength dispersive spectroscopy, and magneto-optical Kerr effect (MOKE) to rapidly screen crystal structure, composition, and magnetic properties, respectively. We found that in-plane magnetic coercive fields of our Vicalloy thin films agree with known bulk values (300 G), but found a remarkable eight times increase of the out-of-plane coercive fields (˜2,500 G). To explain this, we measured the switching fields between in-plane and out-of-plane thin film directions which revealed that the Kondorsky model of 180° domain wall reversal was responsible for Vicalloy's enhanced out-of-plane coercive field and possibly its permanent magnetic properties. The Kondorsky model suggests that domain-wall pinning is the origin of Vicalloy's permanent magnetic properties, in contrast to strain, shape, or

  12. Notification on carrying out the special rectification of rare earth production order nationwide


    To implement "Some Opinions of the State Council of P.R.C. on Promoting the Sustainable and Healthy Development of Rare Earth Industry", regulate and standardize rare earth production order and accelerate the transformation of rare earth industry development pattern, the Ministry of Industry and Information Technology, Ministry of Supervision, Ministry of Environmental Protection, the State Administration of Taxation, the State Administration for Industry and Commerce and the State Administration of Work Safety jointly issued the "Notification on Carrying out the Special Rectification of Rare Earth Production Order Nationwide" and decided to carry out the special campaigns from 2011 August 1 to December 31.

  13. Understanding the influence of nanoenvironment on luminescence of rare-earth ions

    Pushpal Ghosh; Amitava Patra


    This paper presents an overview of the recent results on upconversion and photoluminescence of rare-earth ions in nanoenvironments. The role of the rare-earth ion concentration, crystal size and crystal phase on the up- and downconversion emission of rare-earth ions in oxide nanocrystals and their underlying mechanisms are discussed. It is also found that the luminescence lifetime of the excited state rare-earth ions is sensitive to the particle crystalline phase and size. The analysis suggests that the modifications of radiative and nonradiative relaxation mechanisms are due to local symmetry structure of the host lattice and crystal size respectively.

  14. Effects of rare earths on friction and wear characteristics of magnesium alloy AZ91D

    祁庆琚; 刘勇兵; 杨晓红


    The influence of various rare-earth contents on the friction and wear characteristics of magnesium alloyAZ91D was studied. The results show that the wear resistance properties of rare-earth magnesium alloys are betterthan those of the matrix alloy under the testing conditions. Magnesium alloys undergo transition from mild wear tosevere wear. The addition of rare earths refines the structure of alloys, improves the comprehensive behaviors of themagnesium alloys, increases the stability of oxidation films on worn surfaces, enhances the loading ability of rare-earth magnesium alloys, and delays the transition from mild wear to severe wear effectively.

  15. A study on the Deactivation of Usy Zeolites with Different Rare Earth Contents

    Henriques C.A.


    Full Text Available The deactivation of USY zeolites with different rare earth contents due to the coke formed from n-heptane at 450oC was studied. The results show that the presence of rare earth elements decreases the cracking and coking activities, increasing catalytic stability. However, reaction selectivity was not significantly influenced. The greater the rare earth content, the lower the coking rates and the coke contents. The TPO/DSC profiles suggested that the catalytic effect of the rare earth elements promoted coke oxidation.

  16. On-chip quantum storage in a rare-earth-doped photonic nanocavity

    Zhong, Tian; Kindem, Jonathan M.; Rochman, Jake; Miyazono, Evan; Faraon, Andrei; Ferrier, Alban; Goldner, Philippe


    Rare-earth-ion doped crystals are state-of-the-art materials for optical quantum memories and quantum transducers between optical and microwave photons. Here we describe our progress towards a nanophotonic quantum memory based on a rare-earth (Neodymium) doped yttrium orthosilicate (YSO) photonic crystal resonator. The Purcell-enhanced coupling of the 883 nm transitions of Neodymium (Nd3+) ions to the nano-resonator results in increased optical depth, which could in principle facilitate highly efficient photon storage via cavity impedance matching. The atomic frequency comb (AFC) memory protocol can be implemented in the Nd:YSO nano-resonator by efficient optical pumping into the long-lived Zeeman state. Coherent optical signals can be stored and retrieved from the AFC memory. We currently measure a storage efficiency on par with a bulk crystal Nd:YSO memory that is millimeters long. Our results will enable multiplexed on-chip quantum storage and thus quantum repeater devices using rare-earth-ions.

  17. Geology and genesis of uranium-rare earth deposits at Mary Kathleen, Northwest Queensland

    Scott, A.K.; Scott, A.G.


    The Mary Kathleen uranium deposit occurs in 1740-1780 M yr-old calc-silicate metasedimentary and meta-igneous rocks of the Corella Formation which have been tightly folded into the Mary Kathleen Syncline. The Corella Formation consists of mafic and felsic tuffaceous calc-silicates, quartzite, and minor marble, conglomerate and basic volcanics. Uranium-rare earth mineralisation is closely associated with certain mafic rocks and occurs within or close to garnet-rich masses. At Mary Kathleen, uraninite grains are enclosed mainly by allanite which is distributed through massive garnet as an irregular honeycomb of interconnected shoots and lenses. The mineralisation occurs along strike from dioritic rocks and conglomerate and lies close to the axis of the Mary Kathleen Syncline and adjacent to a major fault zone. At other localities allanite-uraninite mineralisation is broadly stratiform. The mineralisation is interpreted to occur at or near centres of basic volcanism. Garnet formation and uranium-rare earth concentrations are believed to be caused by the volcanism, and to be contemporaneous with it. The former is seen as alteration of a hot, saturated pile of volcano-sedimentary material and the latter as intermittent hydrothermal exhalations. Deposition, volcanism, garnet formation, uranium and rare-earth mineralisation, granite and gabbro formation, and tectonism are seen as a continuum of interrelated processes which operated throughout the period of formation of the rocks in the Mary Kathleen Syncline.

  18. A Physicochemical Method for Separating Rare Earths: Addressing an Impending Shortfall

    Schelter, Eric [Univ. of Pennsylvania, Philadelphia, PA (United States)


    There are currently zero operating suppliers of critical rare earth elements La–Lu, Sc, Y (REs), in the western hemisphere. REs are critical materials due to their importance in clean energy and defense applications, including permanent magnets in wind turbines and phosphors in energy efficient lighting. It is not economically viable to produce pure REs in the U.S. given current separations technology. REs production is dominated by suppliers in the People’s Republic of China (PRC) because of their capacity in liquid­liquid solvent extraction (SX) used to purify mixtures. Weak environmental regulations in the PRC also contribute to a competitive advantage. SX is a cost, time, solvent and waste intensive process but is highly optimized and scalable. The low efficiency of SX derives from the small thermodynamic differences in solvation enthalpy between the RE3+ cations. To foster stable domestic RE production there is a critical need for fundamentally new REs chemistry that contributes to disruptive technologies in RE separations. The overall goal of this project was to develop new thermodynamic bases, and apply them, for the solution separation of rare earth metals. We have developed the chemistry of rare earth metals: La–Lu, Sc and Y, with redox active ligands. Our hypothesis for the project was that electron­hole coupling in complexes of certain lanthanide metals with redox active ligands can be used to manifest chemical distinctiveness and affect separations. We also developed separations based on unique solution equilibria from tailored ligands.

  19. Study on preparation and application of novel saponification agent for organic phase of rare earths extraction

    FENG Zongyu; HUANG Xiaowei; LIU Hongji; WANG Meng; LONG Zhiqi; YU Ying; WANG Chunmei


    In view of the problem of ammonia-nitrogen wastewater pollution in rare earths extraction and separation,the novel saponification agent of organic phase,which is magnesium bicarbonate solution,was prepared with the natural rich and cheap dolomite as mw material through carbonation process.The behavior and purification of main impurities ions in the carbonation process as well as the application effect of the novel saponification agent in the extraction and separation was researched.The results showed that the concentration of Fe,Al,Si impurities ions was.less than 5 ppm in the saponification agent through the development of effective removal technology,respectively.When the novel saponification agent was used in the extraction and separation,magnesium utilization rote was more than 95%,and rare earths extraction rate above 99.5% has achieved.Therefore,the technology could replace ammonia-water to saponify the organic phase in rare earth extraction and separation process.

  20. HEHEHP fractional extraction process with three outlets for separation of Am from rare earths

    何培炯; 焦荣洲; 等


    Americium is similar to light rare earths in solvent extraction by HEHEHP.So the fractional extraction process with three outlets,which is widely used on rare earth industrial scale,can be applied to separate Am from La,Ce,Pr,Nd and Sm.The better process parameters can be calculated by the material and distribution balance equations stage by stage with given organic loading.In order to recover 0.99 mole fraction of Am and remove 0.90 mole fraction of light rare earths from the feed solution,in which the mole ratios of La Ce,Am,Pr,Nd,Sm are 0.140,0.199,0.005,0.109,0.487,0.060,the total number of stages needed is 43,that is the extraction sector 18,first scrubbing sector 2 and second scrubbing sector 23.The fractional extraction process with three outlets is simpler and more convenient than two fractional extraction processes with two outltes.

  1. Stabilization effects of third element on CaCu5 type derivatives of rare-earth transition-metal intermetallics


    Part of the results of the key project "Search for novel rare-earth functional materials" supported by the National Natural Science Foundation of China is reviewed. In combination with reports in literature, the effects of the third element M on the formation and stability of La2(Co, M)17, R(Fe, M)12 and R3(Fe, M)29 intermetallic compounds are discussed by considering mixing enthalpy of M with rare-earth, Fe and Co, and atomic radius, electronegativity and electronic configurations, etc. It is concluded that the mixing en thalpy and atomic radius dominate the preferential sites and the minimum amount of M required to stabilize a structure, which ultimately affect the magnetic properties of a compound prominently. This review should provide some heuristic hints for exploiting novel rare-earth transition metal functional materials and for improving their performance.

  2. Diagenetic uptake of rare earth elements by conodont apatite

    Zhang, L.; Algeo, T. J.; Cao, L.; Zhao, L.; Chen, Z. Q.; Li, Z.


    The rare earth element (REE) composition of bioapatite has long been used as a proxy for ancient seawater chemistry and paleomarine environmental reconstruction, based on the assumption of preservation of a hydrogenous (seawater-derived) REE signal. Recent work, however, has begun to question the provenance of REEs in conodonts, emphasizing the importance of REEs released by the lithogenous fraction of the sediment and subsequently adsorbed onto conodont apatite in the burial environment. Here, we investigate patterns of REE and trace-element abundance in conodonts and their host sediments from the Early to Late Ordovician Huanghuachang and Chenjiahe sections of Hubei Province, South China. Several lines of evidence indicate that REEs in the conodont samples were acquired mainly from clay minerals in the host sediment during burial diagenesis: (1) REEs in conodonts show a strong positive correlation to Th and other lithogenic elements; (2) conodonts and whole-rock samples show general patterns of REE and trace-element enrichment that are highly similar to each other and bear no resemblance to seawater elemental concentrations; (3) similar patterns are observed in Triassic conodonts and whole-rock samples; and (4) Y/Ho ratios in conodonts are mostly 90% of REEs from lithogenous sources. Conodonts show pronounced middle rare earth element (MREE) enrichment, a pattern that is unambiguously of diagenetic origin owing to its association with lower Y/Ho ratios. With increasing MREE enrichment of conodont samples, U concentrations and LaN/YbN ratios shift from high to low, and Mn concentrations from low to high. These patterns suggest that conodont diagenesis was initiated at shallow burial depths under suboxic conditions (i.e., in the zone of Mn(IV) and Fe(III) reduction) but continued at greater burial depths, with most acquisition of secondary REEs at later diagenetic stages. Our findings indicate that (1) conodont apatite frequently does not preserve a recognizable

  3. Rare earth elements in scleractinian cold-water corals

    Raddatz, J.; Liebetrau, V.; Hathorne, E. C.; Rüggeberg, A.; Dullo, W.; Frank, M.


    The Rare Earth Elements (REE) have a great potential to trace continental input, particle scavenging and the oxidation state of seawater. These REE are recorded in the skeleton of the cosmopolitan cold-water corals Lophelia pertusa. Here we use an online preconcentration ICP-MS method (Hathorne et al. 2012) to measure REE concentrations in seawater and associated cold-water coral carbonates in order to investigate their seawater origin. Scleractinian cold-water corals were collected in-situ and alive and with corresponding seawater samples covering from the European Continental Margin. The seawater REE patterns are characterized by the typical negative cerium anomaly of seawater, but are distinct for the northern Norwegian Margin and the Oslo Fjord, probably related to continental input. Initial results for the corresponding coral samples suggest that these distinct REE patterns of ambient seawater are recorded by the coral skeletons although some fractionation during incorporation into the aragonite occurs. This indicates that scleractinian cold-water corals can serve as a valuable archive for seawater derived REE signatures, as well radiogenic Nd isotope compositions. In a second step we analysed fossil coral samples from various locations, which were oxidatively and reductively cleaned prior to analysis. Initial results reveal that sediment-buried fossil (early Pleistocene to Holocene) coral samples from the Norwegian Margin and the Porcupine Seabight (Challenger Mound, IODP Site 1317) do not show the expected seawater REE patterns. In particular, the fossil coral-derived REE patterns lack a negative cerium anomaly suggesting that fossil coral-REE patterns do not represent ambient seawater. Thus, we suggest that the oxidative-reductive cleaning method widely used for cleaning of marine carbonates such as foraminifera prior to measurements of seawater-derived trace metal and isotope compositions are not sufficient for REE and Nd isotopes in sediment-buried coral

  4. Promising wastewater treatment using rare earth-doped nanoferrites

    Ahmed, M.A., E-mail: [Materials Science Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt); Bishay, Samiha T.; Khafagy, Rasha M. [Physics Department, Girls College for Arts, Science and Education, Ain Shams University, Cairo (Egypt); Saleh, N.M. [Physics Department, Faculty of Science, Western Mountain University (Libya)


    Single-phases of the spinel nanoferrites Zn{sub 0.5}Co{sub 0.5}Al{sub 0.5}R{sub 0.04}Fe{sub 1.46}O{sub 4}; R=Sm, Pr, Ce and La, were synthesized using the flash auto combustion method. X-ray diffraction (XRD) results indicated that doping nanoferrites with small concentrations of rare earth elements (RE) allowed their entrance to the spinel lattice. Transmission electron microscope (TEM) images revealed that doping with different RE elements resulted in the formation of different nanometric shapes such as nanospheres and nanowires. Doping with Sm{sup 3+} and Ce{sup 3+} resulted in the formation of nanospheres with average diameter of 14 and 30 nm respectively. In addition to the granular nanospheres, doping with Pr{sup 3+} and La{sup 3+} resulted in the formation of some nanowires with different aspect ratios (average length of ≈100 nm and diameter of ≈9 nm) and (average length of ≈150 nm and outer diameter of ≈22 nm) respectively. At fixed temperature, the Ac conductivity (σ) increased as the RE ionic radius increases except for Ce, due to the role of valance fluctuation from Ce{sup 3+} to Ce{sup 4+} ions. La- and Pr-doped nanoferrites showed the highest ac conductivity values, which is most probably due to the presence of large numbers of nanowires in these two types of ferrites. For all entire samples, the effective magnetic moment (μ{sub eff}) decreased, while the Curie temperature (T{sub C}) increased as the RE ionic radius increases. The synthesized rare earth nanoferrites showed promising results in purifying colored wastewater. La-doped ferrite was capable for up-taking 92% of the dye content, followed by Pr-doped ferrite, which adsorbed 85% of the dye, while Sm- and Ce-doped ferrites showed lower dye removal efficiency of 80% and 72% respectively. High dye uptake shown by La- and Pr-doped ferrites is most probably due to the presence of nanowires and their higher Ac conductivity values. These excellent results were not previously reported

  5. The Current Situation and the Utilization Technique of Rare Earth in China%我国稀土废料回收利用技术与现状

    龚卫星; 李艳荣


    论述了我国稀土资源的回收利用现状,从磁性材料、发光材料及催化剂等可回收的稀土废料方面,说明我国回收稀土废料的利用技术仍处于攻坚阶段。如何回收稀土废料中有用的稀土元素,有待进一步研究。%This paper describes the current situation of recycling the rare earth in China. It proves that the utilization technique of rare earth in China is still in the crucial stage based on the recycling situation of rare earth from magnetic materials, luminescence materials and catalyst, etc,. It needs to be further studied on how to recycle the valuable rare earth elements from the rare earth waste.

  6. Synthesis and characterization of anhydrous rare earth metal nitrates, rare earth acetates and rare earth oxyacetates; Synthese und Charakterisierung wasserfreier Seltenerdmetall-Nitrate, -Acetate und -Oxyacetate

    Heinrichs, Christina


    Anhydrous rare-earth metal (RE) nitrates, RE nitrate monohydrates and RE acetates were synthesized by thermal dehydration of RE nitrate hydrates and RE acetate hydrates in an argon flow or vacuum. RE oxyacetates were synthesized by thermal decomposition of RE acetates. Furthermore praseodymium carbonate hydroxide was synthesized by heating Pr carbonate hydrate. The compounds were analyzed by X-ray powder diffraction and, for selected examples, measurements with high-resolution synchrotron radiation were performed. Three new crystal structure types were found for RE nitrates: RE(NO{sub 3}){sub 3} with RE = La - Sm (type I) crystallize monoclinically in space group C2/c with Z = 16 (CN = 12, 11). RE(NO{sub 3}){sub 3} with RE = Y, Eu - Yb (type II) crystallize monoclinically in space group P2{sub 1}/c with Z = 4 (CN = 10) and Lu(NO{sub 3}){sub 3} (type III) monoclinically in space group I2/a with Z = 16 (CN = 8, 7). With decreasing CN (coordination number) a structural trend within the RE nitrates is observed: The RE nitrates of type I with the largest RE{sup 3+} cations build a three-dimensional network, the RE nitrates of type II form close packed layers and the preliminary structural model of Lu(NO{sub 3}){sub 3} (type III) with the smallest RE{sup 3+} cation shows layers and chains. The product of the dehydration of Sc(NO{sub 3}){sub 3} . n H{sub 2}O was indexed monoclinically in space group P2{sub 1}/c. Monohydrates RE(NO{sub 3}){sub 3} . H{sub 2}O with RE = Dy - Yb crystallize isotypically with Y(NO{sub 3}){sub 3} . H{sub 2}O in the triclinic space group P anti 1 with Z = 2 (CN = 9). Pr(CH{sub 3}CO{sub 2}){sub 3} does not crystallize in the known Pr acetate type but in the trigonal space group R anti 3 with Z = 18 (CN = 10) isotypically with the La acetate type which was only known for La(CH{sub 3}CO{sub 2}){sub 3} and Ce(CH{sub 3}CO{sub 2}){sub 3} up to now. In addition to the known Ho acetate type a new crystal structure type (Ho acetate type II) was found for

  7. Origin of heavy rare earth mineralization in South China

    Xu, Cheng; Kynický, Jindřich; Smith, Martin P.; Kopriva, Antonin; Brtnický, Martin; Urubek, Tomas; Yang, Yueheng; Zhao, Zheng; He, Chen; Song, Wenlei


    Heavy rare earth elements (HREE) are dominantly mined from the weathering crusts of granites in South China. Although weathering processes occur globally, no economic HREE resources of this type have yet been found outside China. Here, we report the occurrence of unidentified REE minerals in the granites from South Chinese deposits. They contain high levels of both HREE and light REE, but are strongly depleted in Ce, implying high oxidation state. These REE minerals show higher initial Nd isotope than primary REE-rich minerals (εNd(t)=0.9+/-0.8 versus -11.5+/-0.5). The mineralized weathering crusts inherited REE signature of the granites, but show more Ce depletion and more overall concentration of the REE. We propose, therefore, that highly oxidized, REE-rich fluids, derived from external, isotopically depleted sources, metasomatized the granites, which resulted in Ce depletion as Ce4+ and enrichment of the remaining REE, especially the HREE, contributing to formation of a globally important REE resource.

  8. Study of octupole correlations in rare earth nuclei

    Babilon, M.


    Possible signatures of octupole correlations are discussed in this thesis for the rare earth nuclei {sup 148-154}Sm and {sup 152}Gd. Microscopic models suggest the occurence of strong octupole correlations in nuclei with N {approx} 88. The available data on {sup 148-154}Sm isotopes allowed for the examination of signatures of octupole correlations through the study of systematics in this region within the framework of the spdf Interacting Boson Approximation (IBA) model. It was found that properties of low-lying states can be readily understood with a simple hamiltonian consisting of a known positive parity hamiltonian coupled to a negative parity boson, and that multiple negative parity bosons were needed to describe properties at higher spin. Experiments on {sup 152}Gd have been performed at wright nuclear structure laboratory of yale university to extend the investigations on octupole correlations to other N=88 nuclei. An experiment at the moving tape collector allowed for the determination of decay properties of low-spin levels in {sup 152}Gd. To obtain information on medium-spin states, including their branchings, a fusion evaporation experiment was performed at the SASSYER setup. Existing data were verified and knowledge of state properties was extended towards higher spins. (orig.)

  9. Electrorheological behavior of rare earth-doped barium titanate suspensions


    Doping Y, La, Ce into barium titanate is found to be able to improve its electrorheological (ER) effect in DC electrical field. The yield stress of a typical doped barium titanate/silicone oil suspension is approximately 3.2 -*7〗kPa at 3.5 -*7〗kV/mm, which is 10 times larger than that of pure barium titanate/silicone oil suspensions. The ER effect increases with the decrease of ionic radius of rare earth (RE) dopant when RE concentration remains constant, and the suspensions exhibit a relatively high shear stress when Y, La, Ce mole fractions are 15%, 10%~15%, and 5%, respectively. Dielectric measurements show that the suitable doping with RE element increases dielectric loss of barium titanate and causes very marked dielectric relaxation at low frequency. By measuring X-ray diffraction patterns of doped barium titanate, it is considered that the occurrence of lattice distortion or defects may be responsible for the change of dielectric properties which results in the improvement of ER effect of barium titanate in DC electrical field.

  10. Magnetostriction of some rare earth-aluminum Laves phase compounds

    Pourarian, F.; Wallace, W. E.


    Measurements of the linear and volume magnetostriction of RAl2 cubic Laves compounds in which R is one of the rare earth elements Gd, Dy, Ho or Er, at temperatures between 4.2 K and the Curie temperature of each compound, are reported. Magnetic fields up to 2.5 Tesla were applied, and magnetostriction was measured using standard strain gage techniques. Saturation magnetostrictions of 17 x 10 to the -6th, -1420 x 10 to the -6th, 60 x 10 to the -6th and -920 x 10 to the -6th are determined at 4.2 K for GdAl2, DyAl2, HoAl2 and ErAl2, respectively. Large forced magnetostriction is observed in GdAl2 above the saturation field and the strain temperature dependence shows a decrease in magnitude below 40 K. A linear dependence of magnetostriction on magnetic field was observed for DyAl2 above 40 K, and the observed temperature dependence is interpreted in terms of the lowest order single-ion magnetoelastic theory. An observed decrease in the magnitude of the strain of HoAl2 below 15 K is associated with a change of the easy direction of magnetization, while in the case of ErAl2, magnetostriction is observed to occur normally up to the Curie temperature. Large volume magnetostriction is obtained for all the compounds with the exception of GdAl2.

  11. Effects of Simulated Rare Earth Recycling Wastewaters on Biological Nitrification.

    Fujita, Yoshiko; Barnes, Joni; Eslamimanesh, Ali; Lencka, Malgorzata M; Anderko, Andrzej; Riman, Richard E; Navrotsky, Alexandra


    Increasing rare earth element (REE) supplies by recycling and expanded ore processing will result in generation of new wastewaters. In some cases, disposal to a sewage treatment plant may be favored, but plant performance must be maintained. To assess the potential effects of such wastewaters on biological treatment, model nitrifying organisms Nitrosomonas europaea and Nitrobacter winogradskyi were exposed to simulated wastewaters containing varying levels of yttrium or europium (10, 50, and 100 ppm), and the extractant tributyl phosphate (TBP, at 0.1 g/L). Y and Eu additions at 50 and 100 ppm inhibited N. europaea, even when virtually all of the REE was insoluble. Provision of TBP with Eu increased N. europaea inhibition, although TBP alone did not substantially alter activity. For N. winogradskyi cultures, Eu or Y additions at all tested levels induced significant inhibition, and nitrification shut down completely with TBP addition. REE solubility was calculated using the previously developed MSE (Mixed-Solvent Electrolyte) thermodynamic model. The model calculations reveal a strong pH dependence of solubility, typically controlled by the precipitation of REE hydroxides but also likely affected by the formation of unknown phosphate phases, which determined aqueous concentrations experienced by the microorganisms.

  12. Rare earth elements in some bottled waters of Serbia

    Todorović Maja


    Full Text Available Twenty-one bottled mineral and spring waters from Serbia were analyzed for 16 inorganic chemical parameters, including lanthanides and yttrium which belong to the group of so-called rare earth elements (REE. REE concentrations in the bottled water samples varied over a broad range, from 5.39 to 1585.82 ng/L. Total concentrations in the bottled water samples were calculated taking into account the classification of lanthanides into heavy (HREE and light (LREE, with yttrium added to the HREE group. The LREE concentrations ranged from 3.62 to 1449.63 ng/L, while those of the HREE were from 0 to 136.19 ng/L. Distinct REE signatures were observed in waters that drained specific rocks. The REE patterns in groundwater from granitic and related rocks showed LREE and HREE enrichment, while groundwater with mafic rock influence exhibited slightly LREE enrichment. Several bottled water samples featured naturally-occurring carbon dioxide, whose solutional capacity contributed to the highest REE concentrations in the analyzed samples. High REE concentrations are also a result of sudden changes in oxidation-reduction conditions, which particularly affect La, Ce and Eu. Aquifers developed in granitic and related rocks (methamorphic and sedimentary rocks constitute favorable environments for HREE in groundwater, corroborated by the occurrence of HREE in bottled water samples. The bottled water samples largely exhibited a negative cerium anomaly and nearly all the samples showed a positive europium anomaly.

  13. Continental shelves as potential resource of rare earth elements.

    Pourret, Olivier; Tuduri, Johann


    The results of this study allow the reassessment of the rare earth elements (REE) external cycle. Indeed, the river input to the oceans has relatively flat REE patterns without cerium (Ce) anomalies, whereas oceanic REE patterns exhibit strong negative Ce anomalies and heavy REE enrichment. Indeed, the processes at the origin of seawater REE patterns are commonly thought to occur within the ocean masses themselves. However, the results from the present study illustrate that seawater-like REE patterns already occur in the truly dissolved pool of river input. This leads us to favor a partial or complete removal of the colloidal REE pool during estuarine mixing by coagulation, as previously shown for dissolved humic acids and iron. In this latter case, REE fractionation occurs because colloidal and truly dissolved pools have different REE patterns. Thus, the REE patterns of seawater could be the combination of both intra-oceanic and riverine processes. In this study, we show that the Atlantic continental shelves could be considered potential REE traps, suggesting further that shelf sediments could potentially become a resource for REE, similar to metalliferous deep sea sediments.

  14. Syntheses and structures of new rare-earth metal tetracyanidoborates

    Falk, Fanni; Hackbarth, Liisa; Koeckerling, Martin [Anorganische Festkoerperchemie, Institut fuer Chemie, Universitaet Rostock, Albert-Einstein-Str. 3a, 18059, Rostock (Germany); Herkert, Lorena; Mueller-Buschbaum, Klaus; Finze, Maik [Institut fuer Anorganische Chemie, Institut fuer nachhaltige Chemie and Katalyse mit Bor (ICB), Julius-Maximilians-Universitaet Wuerzburg, Am Hubland, 97074, Wuerzburg (Germany)


    Six new rare-earth metal tetracyanidoborates were prepared and characterized by single-crystal X-ray diffraction. Crystals of these salts contain co-crystallized solvent molecules, such as water, acetone, ethanol, or diethyl ether. In [La(EtOH){sub 3}(H{sub 2}O){sub 2}{B(CN)_4}{sub 3}] (1), [La(EtOH)(H{sub 2}O){sub 4}{B(CN)_4}{sub 3}].Et{sub 2}O (2), and [Y(EtOH)(H{sub 2}O){sub 4}{B(CN)_4}{sub 3}].EtOH (6) the tetracyanidoborate anions are all or in part bonded to the RE{sup 3+} ions, whereas in [Pr(H{sub 2}O){sub 9}][B(CN){sub 4}]{sub 3}.(CH{sub 3}){sub 2}CO (3), [Er(H{sub 2}O){sub 8}][B(CN){sub 4}]{sub 3}.(CH{sub 3}){sub 2}CO (4), and [Lu(EtOH)(H{sub 2}O){sub 7}][B(CN){sub 4}]{sub 3}.EtOH.0.5H{sub 2}O (5) the [B(CN){sub 4}]{sup -} anions are not coordinated to the central metal atoms. Only in 1, one of the three crystallographically independent [B(CN){sub 4}]{sup -} anions acts as a bridging ligand. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)


    ZHAO Jian; YANG Mujie; ZHENG Yi; SHEN Zhiquan


    The neodymium complex supported on styrene-maleic anhydride copolymer (SMA·Nd) has been prepared for the first time and found to be a highly effective catalyst for the polymerization of styrene. The SMA · Nd polymeric complex is characterized by IR and its catalytic activity, and the polymerization features have been investigated in comparison with that of the conventional Ziegler-Natta catalysts. When [Nd] = 1×10-3 mol/L, [M]=5 mol/L, Al/Nd = 170 (mol ratio ) and CCl4/Nd=50(mol ratio), the polymerization conversion of styrene gets to 51.6% in six hours, and the catalytic activity reaches 1852 gPS/gNd, which is much higher than that of conventional rare earth catalysts. The polymerization reaction has an induction period and shows some characteristics of chain polymerization. The polymerization rate is the first order with respect to the concentration of styrene monomer. Addition of FeCl3 does not suppress the polymerization.

  16. Magnetostriction of some rare earth-aluminum Laves phase compounds

    Pourarian, F.; Wallace, W. E.


    Measurements of the linear and volume magnetostriction of RAl2 cubic Laves compounds in which R is one of the rare earth elements Gd, Dy, Ho or Er, at temperatures between 4.2 K and the Curie temperature of each compound, are reported. Magnetic fields up to 2.5 Tesla were applied, and magnetostriction was measured using standard strain gage techniques. Saturation magnetostrictions of 17 x 10 to the -6th, -1420 x 10 to the -6th, 60 x 10 to the -6th and -920 x 10 to the -6th are determined at 4.2 K for GdAl2, DyAl2, HoAl2 and ErAl2, respectively. Large forced magnetostriction is observed in GdAl2 above the saturation field and the strain temperature dependence shows a decrease in magnitude below 40 K. A linear dependence of magnetostriction on magnetic field was observed for DyAl2 above 40 K, and the observed temperature dependence is interpreted in terms of the lowest order single-ion magnetoelastic theory. An observed decrease in the magnitude of the strain of HoAl2 below 15 K is associated with a change of the easy direction of magnetization, while in the case of ErAl2, magnetostriction is observed to occur normally up to the Curie temperature. Large volume magnetostriction is obtained for all the compounds with the exception of GdAl2.

  17. Review on dielectric properties of rare earth doped barium titanate

    Ismail, Fatin Adila; Osman, Rozana Aina Maulat; Idris, Mohd Sobri


    Rare earth doped Barium Titanate (BaTiO3) were studied due to high permittivity, excellent electrical properties and have wide usage in various applications. This paper reviewed on the electrical properties of RE doped BaTiO3 (RE: Lanthanum (La), Erbium (Er), Samarium (Sm), Neodymium (Nd), Cerium (Ce)), processing method, phase transition occurred and solid solution range for complete study. Most of the RE doped BaTiO3 downshifted the Curie temperature (TC). Transition temperature also known as Curie temperature, TC where the ceramics had a transition from ferroelectric to a paraelectric phase. In this review, the dielectric constant of La-doped BaTiO3, Er-doped BaTiO3, Sm-doped BaTiO3, Nd-doped BaTiO3 and Ce-doped BaTiO3 had been proved to increase and the transition temperature or also known as TC also lowered down to room temperature as for all the RE doped BaTiO3 except for Er-doped BaTiO3.

  18. Size distribution of rare earth elements in coal ash

    Scott, Clinton T.; Deonarine, Amrika; Kolker, Allan; Adams, Monique; Holland, James F.


    Rare earth elements (REEs) are utilized in various applications that are vital to the automotive, petrochemical, medical, and information technology industries. As world demand for REEs increases, critical shortages are expected. Due to the retention of REEs during coal combustion, coal fly ash is increasingly considered a potential resource. Previous studies have demonstrated that coal fly ash is variably enriched in REEs relative to feed coal (e.g, Seredin and Dai, 2012) and that enrichment increases with decreasing size fractions (Blissett et al., 2014). In order to further explore the REE resource potential of coal ash, and determine the partitioning behavior of REE as a function of grain size, we studied whole coal and fly ash size-fractions collected from three U.S commercial-scale coal-fired generating stations burning Appalachian or Powder River Basin coal. Whole fly ash was separated into , 5 um, to 5 to 10 um and 10 to 100 um particle size fractions by mechanical shaking using trace-metal clean procedures. In these samples REE enrichments in whole fly ash ranges 5.6 to 18.5 times that of feedcoals. Partitioning results for size separates relative to whole coal and whole fly ash will also be reported. 

  19. Adjacent stage impurity ratio in rare earth countercurrent extraction process

    CHENG Fuxiang; WU Sheng; LIAO Chunsheng; YAN Chunhua


    Impurity components decrease stage by stage in a cascade of rare earth (RE) extraction separation,and adjacent stage impurity ratio (ASIR) which is defined as the ratio of an impurity's contents in the aqueous/organic phase of two adjacent stages can be used to evaluate the capacity of impurity removal for the two stages.On the basis of extraction equilibrium and mass balance,the ASIR in a two-component extraction separation was deducted and its simplified expressions were given for different process sections according to reasonable assumptions.The calculation simulation was then carried out to obtain the ASIR distribution in the cascade.The results showed that in both the extraction and scrubbing sections the ASIR principally increased with the decrease of the molar proportion of the impurity but along with a flat appearing in the purification zone located in the middle of the cascade.The ASIR intuitively exhibits the nmning status of RE extraction separation and purification,which could provide a theoretic guide for investigating the influence factors of RE extraction separation process in practical industry.

  20. Novel laser nanomaterials based on rare-earth compounds

    Patel, Darayas N., E-mail: [Oakwood University, Department of Mathematics and Computer Science, 7000 Adventist Blvd. Huntsville, AL 35896 (United States); Hardy, Lauren A.; Smith, Tabatha J.; Smith, Eva S.; Wright, Donald M. [Oakwood University, Department of Mathematics and Computer Science, 7000 Adventist Blvd. Huntsville, AL 35896 (United States); Sarkisov, Sergey [SSS Optical Technologies, LLC, 515 Sparkman Drive, Suite 122, Huntsville, AL 35816 (United States)


    We report on the infrared-to-visible upconversion luminescence in microcrystalline powders and photonic crystal fibers filled with nanocolloids of trivalent rare-earth ion co-doped NaYF{sub 4} phosphor. The phosphor was prepared using a simple co-precipitation synthetic method. Nanocolloids of the phosphor were prepared by selective precipitation in methanol and laser ablation in water. Optical dynamic scatterometry determined average particle sizes of the nanocolloids of 1.5-1.9 nm in methanol and 83.8-86.4 nm in water. Nanocolloids of these phosphors were utilized as laser filling medium in photonic crystal fibers. - Highlights: Black-Right-Pointing-Pointer Synthesize highly efficient hexagonal-phase NaYF{sub 4}:Er{sup 3+}, Yb{sup 3+} powder and nanocolloid. Black-Right-Pointing-Pointer Laser/amplifier containing the NaYF{sub 4} nanocolloid were pumped with 980 nm diode laser. Black-Right-Pointing-Pointer Emission peaks were observed at 540 nm, 654 nm and 840.4 nm from the fiber arrangement.