WorldWideScience

Sample records for aqueous rare earth

  1. Uranium, thorium and rare earth extraction and separation process by processing their chloride aqueous solutions

    International Nuclear Information System (INIS)

    The different steps of the process are the following: uranium and iron extraction by a neutral organic phosphorus compound and thorium and rare earth recovery in an aqueous solution, iron recovery in acid aqueous phase, concentration of the thorium and rare earth aqueous solution followed by thorium extraction with a organic phosphorus compound and rare earth recovery in the aqueous phase, thorium recovery in acid aqueous phase

  2. Rare earths in barites: distribution and effects on aqueous partitioning

    International Nuclear Information System (INIS)

    A large variety of barites collected from marine and continental environments was analyzed by neutron activation for the rare-earth elements (REE) La, Ce, Sm, Eu and Dy. Relative to chondrites all barites show a decrease of the lighter REE from La toward Eu. The abundance and distribution of rare earths in barites show a distinction of barite types. Deep-sea barites have large REE concentrations as do other authigenic deep-sea minerals and display the chondrite normalized Eu minimum, but not the negative Ce anomaly, of sea water. Other barites, mostly on land, some hydrothermal, and others of shallow marine origin, display lower total Ree concentrations. Chondrite normalized positive Eu anomalies are displayed by those varieties of reducing sedimentary and metamorphic origin. Distribution of REE in barite can be attributed both to crystallographic constraints of substitution and to solution complexing of REE in the precipitating medium. Plots of rare earth partitioning versus effective ion size suggest that the decreasing enrichment toward Eu for all barite types is caused by crystallographic constraints due to contraction of the substituting REE ion sizes relative to the size of the host Ba ion. Solution effects on REE substitution in barite can be evaluated. Under normal sea water conditions, solution complexing plays a minor role. However, increased alkalinities of reducing sediments and increased brine chlorinities could cause significant complexing and deplete REE heavier than Eu. Besides Dy in barites, this could be true for aqueous precipitation of REE in general. (author)

  3. Rare earths

    International Nuclear Information System (INIS)

    General mineralogical-geochemical and analytical characteristics of (lanthanides and yttrium) are presented. It is pointed out that individual RE in complex chemical composition samples are successfully determined by physical methods of the analysis (emission spectral method, spark mass spectrometry method, neutron + activation analysis). RE sum determination is performed by spectrophotometric titrimetric or gravimetric methods. Principal methods of RE separation and concentration, methods of analytical samples dissolution are considered. Detailed descriptions of some specific techniques of determining rare earths in rocks, ores and minerals are presented

  4. Rare Earth Market Review

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ 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.

  5. Rare Earth Resolution

    Institute of Scientific and Technical Information of China (English)

    Mei Xinyu

    2012-01-01

    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.

  6. Extraction-photometric determination of rare earths with carrying out of colour reaction in aqueous-organic medium

    International Nuclear Information System (INIS)

    The accelerated and safe technique of rare earths (REE) determination in mineral raW materials and products of their processing of complex chemical composition is developed. The technique envisages break-down of the sample weighed amount by treatment with the mixtures of acids at heating, extraction of REE with technical mixture of fatty acids C7-C9 and subsequent determination of REE microamounts in the extract. The coloured reaction of REE with arsenazo 3 is carried out in aqueous-organic solution which is prepared when mixing the extract with ice acetic and 0.01 M hydrochloric acids

  7. Spectrophotometric determination of Rare Earth Elements in aqueous nitric acid solutions for process control.

    Science.gov (United States)

    Rodionova, Oxana Ye; Tikhomirova, Tatyana I; Pomerantsev, Alexey L

    2015-04-15

    Noninvasive analytical control is of special interest for the complicated and hazardous production processes. On-line monitoring provides a unique opportunity to determine critical concentrations rapidly and without serious risks to operating personnel and the environment. Models for quantitative determination of concentrations of Rare Earth Elements in complex mixtures in nitric acid serve for these purposes. Here, the feasibility of simultaneous determination of cerium, praseodymium, and neodymium using the whole UV-vis spectroscopic range, together with chemometric data processing, is studied. The predictability of two chemometric techniques, partial least squares regression and correlation constrained multivariate curve resolution-alternating least squares are compared. Models' performances are analyzed in out-of-control cases. PMID:25818140

  8. Solvent extraction of rare earth(3) nitrates with dioctylisoamylphosphine oxide from aqueous solutions

    International Nuclear Information System (INIS)

    Distribution of lanthanide(3) and yttrium(3) nitrates (Re(3)) between their aqueous solutions and 30% solution of dioctylisoamylphosphine oxide (DOIAPO, S) in kerosene and n-pentadecane at 298.15 K, pH 2 is studied. Production of [Ln(NO3)3S3] composition solvates is ascertained. Equations for describing isotherms of Re(3)DOIAPO nitrate extraction under a broad variation of aqueous and organic phase composition are proposed. Values of phase extraction equilibria constants are determined. It is ascertained that extraction constant values grow under transition from lanthanum(3) to europium(3), and then are reduced under transition from gadolinium(3) to lutetium(3). Extraction constant value for yttrium is between extraction constant values for thulium(3) and ytterbium(3). 14 refs., 2 figs., 3 tabs

  9. Afganistan and rare earths

    OpenAIRE

    Emilian M. Dobrescu; Edith Mihaela Dobre

    2013-01-01

    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 ...

  10. Thermodynamic studies on the interaction between some amino acids with some rare earth metal ions in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, AbdAllah A.; Bakr, Moustafa F.; Abd El-Fattah, Khaled A

    2003-11-06

    The interactions between the amino acids (glycine and L-threonine) with some rare earth metal ions (Pr{sup 3+}, Nd{sup 3+}, Eu{sup 3+}, Gd{sup 3+}, Dy{sup 3+}, Ho{sup 3+} and Yb{sup 3+}) were studied at a wide range from ionic strengths (0.07-0.32 M KNO{sub 3}) and temperatures (25-45 deg. C) in aqueous solutions by using Bjerrum potentiometric method. The stoichiometric and thermodynamic stability constants were calculated as well as the standard thermodynamic parameters ({delta}G deg., {delta}H deg. and {delta}S deg. ) for all possible reactions that occur. The degree of formation (n-bar) for all studied systems was determined and discussed. The thermodynamic parameters differences ({delta}{delta}G deg., {delta}{delta}H deg. and {delta}{delta}S deg. ) were calculated and discussed to determine the factors which control these complexation processes from the thermodynamic point of view.

  11. Rare (Earth Elements [score

    Directory of Open Access Journals (Sweden)

    Camilo Méndez

    2014-12-01

    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.

  12. Magnetic rare earth superlattices

    DEFF Research Database (Denmark)

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

    1991-01-01

    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...

  13. Afganistan and rare earths

    Directory of Open Access Journals (Sweden)

    Emilian M. Dobrescu

    2013-05-01

    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.

  14. China Rare Earth Market Review

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ 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.

  15. China Rare Earth Market Review

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ 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.

  16. 2004 China Rare Earth Review

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    production1. Rare Earth MineralsIn 2004, output of rare earth minerals kept on increasing,approached 98,300 tons including Baotou ore 46,600 tons,Sichuan ore 21,700 tons and ion adsorption rare earth ore30,000 tons (calculated by REO, following the same),increasing 6.84% over previous year (Table 1).Table 1 Constitution of Chinese Rare Earth Mineralsin 2004 (REO, ton)OutputTotalMixed RE Ore46,600Ion AdsorptionRE Ore30,000Bastnaesite21,70198,3102. Rare Earth Smelted and Separated ProductsProduction of rare e...

  17. China Rare Earth Market Review

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ 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.

  18. Japanese Rare Earth Market

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    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...

  19. Magnetic rare earth superlattices

    DEFF Research Database (Denmark)

    Majkrzak, C.F.; Kwo, J.; Hong, M.; Yafet, Y.; Gibbs, D.; Chien, C.L.; Bohr, Jakob

    1991-01-01

    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....... The primary goal of this article is to review the new and interesting magnetic structures which have been discovered in these novel superlattice systems and to consider what implications the observed phases have on our understanding of the underlying microscopic magnetic interactions. In particular......, the effects of the artificial periodicity or compositional modulation, finite layer thickness, and epitaxial strain on the resulting long range magnetic order of Gd-Y, Dy-Y, Ho-Y, Er-Y, and Gd-Dy superlattices are described....

  20. Rare earth ferrosilicon alloy

    International Nuclear Information System (INIS)

    In order to obtain RE ferrosilicon alloy with good quality and competitive price, it is essential that proper choice of raw materials, processing technology and equipments should be made based on the characteristics of Bai-Yun-Ebo mineral deposits. Experimental work and actual production practice indicate that pyrometallurgical method is suitable for the extraction and isolation of the rare earths and comprehensive utilization of the metal values contained in the feed material is capable of reducing cost of production of RE ferrosilicon alloy. In the Bai-Yun-Ebo deposit, the fluorite type medium lean ore (with respect to iron content) makes a reserve of considerable size. The average content of the chief constituents are given

  1. China rare earth market review

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    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

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    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.

  3. China rare earth market review

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    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.

  4. China Rare Earth Market Review

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    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.

  5. China's rare-earth industry

    Science.gov (United States)

    Tse, Pui-Kwan

    2011-01-01

    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.

  6. Rare earths 1998 market update

    International Nuclear Information System (INIS)

    The rare earth industry has always been a world of rapid change with the emergence of new markets, new ores and new players, as well as the disappearance of old applications. Rare earth based products are used in a great diversity of applications such as hard disk drives, CD drives, batteries, capacitors, pigments, ceramics, polishing powders, fuel cells, flints, catalyst converter, fluid cracking catalysts, etc. South East Asia holds the largest share of the known reserve of rare earth ores and is one of the major markets for rare earth compounds; in the last ten years, China has become the largest producer of rare earth intermediates as well as an important exporter of separated rare earth elements. Today, China has approximately 150 factories producing rare earth compounds, most of which are experiencing financial difficulties due to the lack of knowledge of true market needs, lack of control of their distribution channels and production over-capacity. Recently the Chinese rare earth producers have recognized the situation and efforts are underway to rationalize rare earth production. Japan has dominated many of the major application markets, and is by far the largest market for metal and alloy products. This will remain the case for the next five years; however, new countries are emerging as significant users of rare earth products such as Korea, Taiwan and Malaysia. During the last ten years rare earth producers adjusted to several radical changes that affected the raw materials, the application mix and the price structure. New producers have emerged, especially from China; some have subsequently stopped their activities while others have focused their efforts in a specific market segment

  7. Effect of Rare Earth Oxide Content on Nanograined Base Metal Electrode Multilayer Ceramic Capacitor Powder Prepared by Aqueous Chemical Coating Method

    Science.gov (United States)

    Zhang, Yichi; Wang, Xiaohui; Kim, Jinyong; Li, Longtu

    2013-02-01

    The aqueous chemical coating route is highly effective in preparing BaTiO3 nanoparticles uniformly coated with additives. Such nanoparticles can be used to produce nano-grained temperature stable BaTiO3 ceramics with core-shell structure, fulfilling the need of next-generation ultrathin layer base metal electrode (BME) multilayer ceramic capacitors (MLCCs). Rare earth oxides are an important class of additives owing to their ability to fulfill both donor and acceptor roles. In this paper, the effects of Y2O3 and Ho2O3 co-dopant content on dielectric and microstructural properties were investigated. By applying chemical coating, BaTiO3-based high performance temperature stabilized ceramics with the average grain size of about 130 nm, which met the requirement of next generation BME MLCCs, were obtained.

  8. The Not-So-Rare Earths.

    Science.gov (United States)

    Muecke, Gunter K.; Moller, Peter

    1988-01-01

    Describes the characteristics of rare earth elements. Details the physical chemistry of rare earths. Reviews the history of rare earth chemistry and mineralogy. Discusses the mineralogy and crystallography of the formation of rare earth laden minerals found in the earth's crust. Characterizes the geologic history of rare earth elements. (CW)

  9. Phase stable rare earth garnets

    Science.gov (United States)

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

    2013-06-11

    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.

  10. On the Rare Earth Frontier

    OpenAIRE

    Klinger, Julie Michelle

    2015-01-01

    Rare earth elements are not rare at all. They are essential for the hardware of contemporary life as we know it, every contemporary industrialized society depends on them, and there are no known alternatives. Yet the geography of their production is strange. In 2009, China accounted for 97% percent of global production, with the majority coming from the Bayan Obo mine operated by the state-owned enterprise Baotou Rare Earth Group on the southern Mongolian steppe. When gradually intensifyin...

  11. Processing of rare earth concentrates

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

    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.

  12. IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 3. Heavy Lanthanides (Gd–Lu)

    Energy Technology Data Exchange (ETDEWEB)

    Mioduski, Tomasz [Institute of Nuclear Chemistry and Technology, 03195 Warszawa (Poland); Gumiński, Cezary, E-mail: cegie@chem.uw.edu.pl [Department of Chemistry, University of Warsaw, 02093 Warszawa (Poland); Zeng, Dewen, E-mail: dewen-zeng@hotmail.com [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)

    2015-06-15

    This is the third part of the volume devoted to solubility data for the rare earth metal (REM) fluorides in water and in aqueous ternary and multicomponent systems. It covers experimental results of trivalent fluorides of Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu (so-called heavy lanthanides), since no quantitative data on solubilities of TbF{sub 4} and YbF{sub 2} (the most stable compounds at these valencies) are available. The related literature has been covered through the end of 2014. Compilations of all available papers with the solubility data are introduced for each REM fluoride with a corresponding critical evaluation. Every such assessment contains a collection of all solubility results in aqueous solution, a selection of suggested solubility data, a solubility equation, and a brief discussion of the multicomponent systems. Only simple fluorides (no complexes or double salts) are treated as the input substances in this report. General features of the systems, such as nature of the equilibrium solid phases, solubility as a function of temperature, influence of ionic strength, solution pH, mixed solvent medium on the solubility, quality of the solubility results, and the solubility as a function of REM atomic number, have already been presented in Part 1 of the volume.

  13. Rare earth industries: Downstream business

    International Nuclear Information System (INIS)

    The value chain of the rare earths business involves mining, extraction, processing, refining and the manufacture of an extensive range of downstream products which find wide applications in such industries including aerospace, consumer electronics, medical, military, automotive, renewable wind and solar energy and telecommunications. In fact the entire gamut of the high-tech industries depends on a sustainable supply of rare earths elements. The explosive demand in mobile phones is an excellent illustration of the massive potential that the rare earths business offers. In a matter of less than 20 years, the number of cell phones worldwide has reached a staggering 5 billion. Soon, going by the report of their growth in sales, the world demand for cell phones may even exceed the global population. Admittedly, the rare earths business does pose certain risks. Top among the risks are the health and safety risks. The mining, extraction and refining of rare earths produce residues and wastes which carry health and safety risks. The residues from the extraction and refining are radioactive, while their effluent waste streams do pose pollution risks to the receiving rivers and waterways. But, as clearly elaborated in a recent report by IAEA experts, there are technologies and systems available to efficiently mitigate such risks. The risks are Rare Earth manageable. However, it is crucial that the risk and waste management procedures are strictly followed and adhered to. This is where effective monitoring and surveillance throughout the life of all such rare earths facilities is crucial. Fortunately, Malaysia's regulatory standards on rare earths follow international standards. In some areas, Malaysia's regulatory regime is even more stringent than the international guidelines. (author)

  14. China Rare Earth Holdings Limited

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    Chang-Mao Hung

    2011-01-01

    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.

  16. Rare Earth Separation in China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    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.

  17. Development Trend of Rare Earth Standardion Work

    Institute of Scientific and Technical Information of China (English)

    Ma Jie; Lin Jirong; Zhao Fei; Zhang Xiuyan

    2004-01-01

    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.

  18. Sulfochrome interaction with rare earths

    International Nuclear Information System (INIS)

    The reactions between 3,3'-dimethyl-4hydroxyfuchson-4'.(5,5'-dicarboxy-2'',4''-disulfonic acid as its diammonium salt (sulfochrom, SC) and the rare earths have been studied spectrophotometrically in the absence and in the presence of o-phenanthroline (Phen). Regions have been found for the existance of two-component and mixed complexes as dependent of the pH and the serial number of the rare earth. The slope analysis has shown that the molar ratio of the components in the mixed-ligand compound is M:SC:Phen=1:2:2. A procedure is suggested of determining some elements of the yttrium subgroup in the presence of the cerium subgroup elements

  19. Rare Earth Optical Temperature Sensor

    Science.gov (United States)

    Chubb, Donald L.; Wolford, David S.

    2000-01-01

    A new optical temperature sensor suitable for high temperatures (greater than 1700 K) and harsh environments is introduced. The key component of the sensor is the rare earth material contained at the end of a sensor that is in contact with the sample being measured. The measured narrow wavelength band emission from the rare earth is used to deduce the sample temperature. A simplified relation between the temperature and measured radiation was verified experimentally. The upper temperature limit of the sensor is determined by material limits to be approximately 2000 C. The lower limit, determined by the minimum detectable radiation, is found to be approximately 700 K. At high temperatures 1 K resolution is predicted. Also, millisecond response times are calculated.

  20. Rare earth industries: Upstream business

    International Nuclear Information System (INIS)

    Evidently, many factors contribute to the rush to invest in the unprecedented revival of rare earths. One major reason has to do with the rapidly growing world demand. The other reason relates to the attractive price of rare earths which is projected to stay strong in the coming years. This is because supply is predicted to have difficulty keeping pace with demand. Experts believe a major driver of global rare earths demand is the forecasted expansion in the green economy. Climate change is a major driver of the green economy. With climate change, there is concern that the uncontrolled emission of the greenhouse gases, especially carbon dioxide, can lead to catastrophic consequences for the world. This has been documented in countless studies and reports. Another important driver of the green economy is the growing shortfall in many resources. The world is now experiencing declines in key resources to meet a growing global demand. With more than 6 billion people now in the world and growing, the pressure exerted on global resources including energy, water and food is a major concern. Recent demand surge in China and India has dented the supply position of major world resources. The much quoted Stern Report from the UK has warned that, unless immediate steps are taken to reduce greenhouse gas emissions, it may be a costly exercise to undertake the corrections later. Since energy use, especially fossil fuels, is a major contributor to climate change, greener options are being sought. Add to that the fact that the fossil energy resources of the world are declining, the need to seek alternatives becomes even more urgent. One option is to change to renewable energy sources. These include such potentials as solar, wind and biomass. Rare earths have somehow become a critical feature of the technologies in such renewable. Another option is to improve the efficient use of energy in transport, buildings and all the other energy intensive industries. Again the technologies in

  1. Rare Earths and Magnetic Refrigeration

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    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.

  2. Rare Earth Oxide Thin Films

    CERN Document Server

    Fanciulli, Marco

    2007-01-01

    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.

  3. Baotou Research Institute of Rare Earths

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Established in 1963, Baotou Research Institute of Rare Earths is the largest comprehensive institute engaging in R (εt) D and application of rare Dr. Zhao Zengqi. President of BRIRE earths in China.

  4. 2006 Rare Earth Export Quota

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ 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.

  5. Rare earths, the lanthanides, yttrium and scandium

    Science.gov (United States)

    Hedrick, J.B.

    2006-01-01

    In 2005, rare earths were not mined in the United States. The major supplier, Molycorp, continued to maintain a large stockpile of rare-earth concentrates and compounds. Consumption decreased of refined rare-earth products. The United States remained a major importer and exporter of rare earths in 2005. During the same period, yttrium was not mined or refined in the US. Hence, supply of yttrium compounds for refined yttrium products came from China, France and Japan. Scandium was not also mined. World production was primarily in China, Russia and Ukraine. Demand for rare earths in 2006 is expected to be closely tied to economic conditions in the US.

  6. Research on Rare Earth Encapsulated Luminescent Material

    Institute of Scientific and Technical Information of China (English)

    Yu Zhiwei; Liu Chengdong; Qi Xiaopeng

    2004-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    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.

  8. Refining of light rare, rare earth and radioactive metals

    International Nuclear Information System (INIS)

    Overview of technologies for the production of high-purity light rare, rare earth, radioactive metals and their compounds: electrolytic refining, vacuum distillation, electron-beam and zone melting, directed crystallization, electrotransfer, extraction, ion exchange

  9. Laser emission spectrography of rare earth elements

    International Nuclear Information System (INIS)

    Emission spectrography of rare earth elements in several matrixes is studied by using a Q-switched ruby laser as an exciting source for macro analysis. The emission intensities of rare earth elements are considerably affected by the matrixes. The emission intensities of rare earth elements are most intense in sodium chloride matrix, but fairly suppressed in sodium sulfate matrix. Scandium, yttrium, europium, and ytterbium, in sodium chloride matrix are detected down to concentrations of ppm order with one laser shot. The emission intensities of rare earth elements in refractory oxides, such as aluminum oxide or rate earth oxides, are about two orders of magnitude less than those in sodium chloride matrix. (auth.)

  10. Rare earth industries: Strategies for Malaysia

    International Nuclear Information System (INIS)

    Evidently, many reports cite Malaysia as having reasonably substantial amounts of rare earths elements. In fact, based on the rare earths found in the residual tin deposits alone, Malaysia has about 30,000 tonnes. This does not take into account unmapped deposits which experts believe may offer more tonnages of rare earths. Brazil which is reported to have about 48,000 tonnes has announced plans to invest aggressively in the rare earths business. China has on record the largest reserves with about 36 million tonnes. This explains why China has invested heavily in the entire value chain of the rare earths business. Chinas committed investment in rare earths started many years ago when the country's foremost leaders proclaimed the strategic position of rare earths in the world economy. That forecast is now a reality where the rise in the green high-tech economy is seen driving global demand for rare earths in a big way. Malaysia needs to discover and venture into new economic growth areas. This will help fuel the country's drive to achieve a high income status by 2020 as articulated in the New Economic Model (NEM) and the many supporting Economic Transformation Plans that the Government has recently launched. Rare earths may be the new growth area for Malaysia. However, the business opportunities should not just be confined to the mining, extraction and production of rare earths elements alone if Malaysia is to maximise benefits from this industry. The industry's gold mine is in the downstream products. This is also the sector that China wants to expand. Japan which now controls about 50 % of the global market for downstream rare earths-based high-tech components is desperately looking for partners to grow their stake in the business. Malaysia needs to embark on the right strategies in order to build the rare earths industry in the country. What are the strategies? (author)

  11. Rare earth - no case for government intervention

    OpenAIRE

    Georg Zachmann

    2010-01-01

    China has officially restricted exports of rare earth for several years and announced this year it will further tighten exports. Rare earth is a group of 17 different metals, usually found clustered together. These metals have hundreds of different industry applications. For example, they are used in certain high capacity magnets, batteries and lasers. As the rare earth elements are used in sectors that are assumed to have an over-proportionate growth potential (eg. green-technology), policy ...

  12. Review on Rare Earth/Polymer Composite

    Institute of Scientific and Technical Information of China (English)

    刘力; 张立群; 赵素合; 金日光; 刘美琳

    2002-01-01

    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.

  13. Alaska's rare earth deposits and resource potential

    Science.gov (United States)

    Barker, James C.; Van Gosen, Bradley S.

    2012-01-01

    Alaska’s known mineral endowment includes some of the largest and highest grade deposits of various metals, including gold, copper and zinc. Recently, Alaska has also been active in the worldwide search for sources of rare earth elements (REE) to replace exports now being limitedby China. Driven by limited supply of the rare earths, combined with their increasing use in new ‘green’ energy, lighting, transportation, and many other technological applications, the rare earth metals neodymium, europium and, in particular, the heavy rare earth elements terbium, dysprosium and yttrium are forecast to soon be in critical short supply (U.S. Department of Energy, 2010).

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

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhanheng

    2011-01-01

    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.

  15. 2nd conference on rare earths

    International Nuclear Information System (INIS)

    The conference heard a total of 16 papers of which 8 were incorporated in INIS, namely those dealing with the separation of rare earths from mineral raw materials (Kola apatite, bastnaesite ore), the best methods of preparing rare earth compounds for the production of polishing powders, and design of an experimental mixer-settler. (E.S.)

  16. Theory of Rare-Earth Alloys

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1977-01-01

    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...

  17. Rare earth elements and strategic mineral policy

    NARCIS (Netherlands)

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

    2010-01-01

    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

  18. Rare Earth Elements Distribution in Beryl

    International Nuclear Information System (INIS)

    Laser ablation method is applied to a double focusing inductively coupled plasma mass spectrometer to determine the rare earth element distribution in some selected beryl samples. White, green and blue beryl samples are selected from the Egyptian eastern desert. Distributions of chondrite- normalized plot for the rare earth element in the selected beryl samples are investigated

  19. Soluble rare-earth chalcogenides

    Science.gov (United States)

    Pernin, Christopher G.

    1999-11-01

    The cluster Eu8(DMF)13(mu4-O)(mu 3-OH)12(Se3)(Se4)2(Se 5)2 was synthesized from the reaction of EuCl3 dissolved in tetrahydrofaran with K2Se4 dissolved in N,N-dimethylformamide (DMF). The Eu8(O)(OH)12 10+ core is the first example such a polyoxometallo-core. The compound is further unusual in that it contains three different polyselenide chain lengths attaching adjacent Eu atoms. A similar reaction between Ln Cl3·6H2O and K2Se4 in DMF was found to produce the cluster compounds Gd8(DMF) 13(mu4-O)(mu3-OH)12(Se3)(Se 4)2(Se5)2, Yb8 (DMF) 11(mu4-O)(mu3-OH)12(Se4) 2(Se5)2Cl2·(DMF), and Y 8(DMF)12(mu4-O)(mu3-OH)12 (Se4)4Cl2·(DMF)6. Each of these clusters has a similar Ln8(mu 4-OH)(mu3-OH)1210+ core coordinated by a variety of polyselenide and chloride ligands. The organometallic rare-earth chalcogenide compounds (C5H 5)2Y [N( Q PPh2)2] ( Q = S, Se) have been prepared in good yield from the protonolysis reaction between CP3Y and HN( Q PPh2)2 in THF. In both compounds, the [N( Q PPh2)2]-- ligand is bound eta 3 to the Y center. The Y atom is also coordinated to two (C5 H5)-- ligands and so is formally 9-coordinate. 1H, 31P, 77Se, and 89Y NMR data indicate that the solid state connectivity is retained in solution. The compounds (C5H5)2Ln[N( Q PPh2)2] (Ln = La, Gd, Er, Yb, for Q = Se; Ln = Yb for Q = S) were synthesized. The series of compounds indicates that the smaller rare-earth elements cannot accommodate eta3-bonding from the imidodiphosphinochalcogenido ligand. The compounds Y[N( Q PPh2)2]3 ( Q = S (1), Se(2)) have been synthesized from the reactions between Y[N(SiMe3)2]3 and HN( Q PPh2)2. In 1, the Y atom is surrounded by three similar [N(SPPh2)2]-- ligands bound eta3 through two S atoms and an N atom. In 2 , the Y atom is surrounded again by three [N(SePPh2) 2]-- ligands, but two are bound eta2 through the two Se atoms and the other ligand is bound eta3 through the two Se atoms and an N atom. Although a fluxional process is detected in the 31P and 77Se NMR spectra

  20. Contribution for the studies of rare earth dithionates

    International Nuclear Information System (INIS)

    The main objective of this work is the synthesis and investigation of some properties of rare earth dithionates. The rare earth dithionates were prepared from the respective sulphates, by the reaction of the latter with BaS sub(2) O sub(6) in aqueous solutions. The lanthanide ion content was estimated by complexometric titration with EDTA; analysis for H were carried out by microanalysis and the water content was determinated by Karl Fischer titration. This experimental results in addition to thermogravimetric (TG) data gave the stoichiometry of the compounds. (author)

  1. Solar Energy Cell with Rare Earth Film

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

    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.

  2. Recovery of rare earths from red mud

    International Nuclear Information System (INIS)

    The prospect for the recovery of rare earths from red mud, the bauxite tailings from the production of alumina is examined. The Jamaican red mud by far has the higher trace concentrations of lanthanum, cerium, neodymium, and yttrium. Scandium is also present. The dissolution of the rare earth is a major extraction problem because of the large volume of other materials. The recovery processes that have been proposed include the production of co-products such as iron, alumina, and titanium concentrates, with the rare earths going with the titanium. In this paper a critical examination of the possible processes are presented with the recommended research projects to be carried out

  3. China Not the Only Rare Earth Exporter

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    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

  4. Rare earth element mines, deposits, and occurrences

    Data.gov (United States)

    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...

  5. Rare earth aerosol analysis by XRF

    International Nuclear Information System (INIS)

    An analytical method utilizing x-ray fluorescence (XRF) spectrometry is described to determine simultaneously the amounts of lanthanum, cerium, praseodymium, and neodymium in air-filter samples collected at a rare-earth processing refinery in Illinois

  6. Partitioning properties of rare earth ores in China

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

    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.

  7. 2004 Top 10 Chinese Rare Earth Events

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    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

  8. Chromatographic separation and analysis of rare earths

    International Nuclear Information System (INIS)

    It is shown that difficult inorganic separation problems can be solved by a simple and inexpensive method. Examples: 1. Separation of rare earths by means of thin-layer chromatography in analyses of minerals, highest grade materials, and fission products within a fuel element; 2. Separation and quantitative determination of rare earths by means of high-pressure liquid chromatography in analyses of monazite sands, cerium composition metals, and fission products. (RB)

  9. Method for rare earth extraction from phosphogypsum

    International Nuclear Information System (INIS)

    A method for rare earth extraction from phosphogypsum, permitting to increase the degree of extraction and to simplify the process, has been suggested. Phosphogypsum is treated by a solution of ammonium carbonate, the precipitate of calcium carbonate formed is dissolved in 55-70% of stoichiometry of nitric acid and insoluble residue is dissolved in HNO3. The degree of rare earth extraction into solution reaches 94-98%

  10. Government Documents on Rare Earth Minerals

    OpenAIRE

    Chapman, Bert

    2012-01-01

    Rare earth minerals contain unique chemical and physical properties such as lanthanum, are found in small concentrations, need extensive precise processes to separate, and are critical components of modern technologies such as laser guidance systems, personal electronics such as Blackberries, and satellites. The U.S. has some rare earth resources, but is heavily dependent on access to them from from Afghanistan, Bolivia, and China. Losing access to these resources would have significant econo...

  11. Superconductivity in rare earth and actinide compounds

    International Nuclear Information System (INIS)

    Rare earth and actinide compounds and the extraordinary superconducting and magnetic phenomena they exhibit are surveyed. The rare earth and actinide compounds described belong to three classes of novel superconducting materials: high temperature, high field superconductors (intermetallics and layered cuprates); superconductors containing localized magnetic moments; heavy fermion superconductors. Recent experiments on the resistive upper critical field of high Tc cuprate superconductors and the peak effect in the critical current density of the f-electron superconductor CeRu2 are discussed. (orig.)

  12. Review and forecast of China rare earth industry

    Institute of Scientific and Technical Information of China (English)

    SONG Hongfang; HONG Mei

    2010-01-01

    @@ China rare earth industry develops in a fast and stable way in recent years. Domestic rare earth consumption increases rapidly and the consumption structure is markedly optimized. Export volume of rare earths is reduced but the price rises. Rare earth industrial clusters develop fast and harmoniously. Exploitation, distribution and utilization of rare earth resources are further improved. Rare earth enterprises step forward to-ward the scaled and group managing way. The industry concentration is significantly enhanced.

  13. Magnetic Rare-Earth Superlattices

    DEFF Research Database (Denmark)

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

    1988-01-01

    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...

  14. Investigation of solvent extraction of rare earths and Am with triisoamyl phosphate

    International Nuclear Information System (INIS)

    Extraction of nitric acid, microamounts of individual rare earths, mixtures of rare earth macroamounts by triisoamyl phosphate (TIAP) depending on the HNO3, LiNO3 cconcentration and concentration of extratant in dodecane has been studied. It is shown that Ln(NO3)3x3TIAP is the main form of the rare earth existence in the organic phase. Comparison of extraction properties of TBP and TIAP, as to rare earths, has shown that TIAP differs but slightly from TBP in extractability and selectivity and it can be used in the rare earth separation processes. A lower solubility of TIAP in the aqueous phase and the absence of the third phase during extraction of rare earth macroamounts by TIAP solutions in a neutral diluent are the advantages of TIAP, as compared with TBP, for the rare earth separation

  15. Anisotropy of rare-earth magnets

    Institute of Scientific and Technical Information of China (English)

    R.Skomski; D.J.Sellmyer

    2009-01-01

    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.

  16. On the formation and structure of rare-earth element complexes in aqueous solutions under hydrothermal conditions with new data on gadolinium aqua and chloro complexes

    Science.gov (United States)

    Mayanovic, Robert A.; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

    2007-01-01

    Synchrotron X-ray spectroscopy experiments were made on the Gd(III) aqua and chloro complexes in low pH aqueous solutions at temperatures ranging from 25 to 500????C and at pressures up to 480??MPa using a hydrothermal diamond anvil cell. Analysis of fluorescence Gd L3-edge X-ray absorption fine structure (XAFS) spectra measured from a 0.006m Gd/0.16m HNO3 aqueous solution at temperatures up to 500????C and at pressures up to 260??MPa shows that the Gd-O distance of the Gd3+ aqua ion decreases steadily at a rate of ??? 0.007??A??/100????C whereas the number of coordinated H2O molecules decreases from 9.0 ?? 0.5 to 7.0 ?? 0.4. The loss of water molecules in the Gd3+ aqua ion inner hydration shell over this temperature range (a 22% reduction) is smaller than exhibited by the Yb3+ aqua ion (42% reduction) indicating that the former is significantly more stable than the later. We conjecture that the anomalous enrichment of Gd reported from measurement of REE concentrations in ocean waters may be attributed to the enhanced stability of the Gd3+ aqua ion relative to other REEs. Gd L3-edge XAFS measurements of 0.006m and 0.1m GdCl3 aqueous solutions at temperatures up to 500????C and pressures up to 480??MPa reveal that the onset of significant Gd3+-Cl- association occurs around 300????C. Partially-hydrated stepwise inner-sphere complexes most likely of the type Gd(H2O)??-nCln+3-n occur in the chloride solutions at higher temperatures, where ?? ??? 8 at 300????C decreasing slightly to an intermediate value between 7 and 8 upon approaching 500????C. This is the first direct evidence for the occurrence of partially-hydrated REE Gd (this study) and Yb [Mayanovic, R.A., Jayanetti, S., Anderson, A.J., Bassett, W.A., Chou, I-M., 2002a. The structure of Yb3+ aquo ion and chloro complexes in aqueous solutions at up to 500 ??C and 270 MPa. J. Phys. Chem. A 106, 6591-6599.] chloro complexes in hydrothermal solutions. The number of chlorides (n) of the partially-hydrated Gd

  17. Rare earth phosphors and phosphor screens

    Science.gov (United States)

    Buchanan, Robert A.; Maple, T. Grant; Sklensky, Alden F.

    1981-01-01

    This invention relates to rare earth phosphor screens for converting image carrying incident radiation to image carrying visible or near-visible radiation and to the rare earth phosphor materials utilized in such screens. The invention further relates to methods for converting image carrying charged particles to image carrying radiation principally in the blue and near-ultraviolet region of the spectrum and to stabilized rare earth phosphors characterized by having a continuous surface layer of the phosphors of the invention. More particularly, the phosphors of the invention are oxychlorides and oxybromides of yttrium, lanthanum and gadolinium activated with trivalent cerium and the conversion screens are of the type illustratively including x-ray conversion screens, image amplifier tube screens, neutron imaging screens, cathode ray tube screens, high energy gamma ray screens, scintillation detector screens and screens for real-time translation of image carrying high energy radiation to image carrying visible or near-visible radiation.

  18. Valence of 'divalent' rare earth metals

    International Nuclear Information System (INIS)

    It is generally recognized that light rare earths change their valence from 2 to 3 when forming a bulk metal while remaining divalent at the surface. However, performed DFT calculations ultimately indicate that the higher-binding-energy peaks in photoemission spectra (like the -5.3 eV peak for Sm), characteristic of the trivalent 4fn-15d1 configuration, correspond not to the ground state, but to excited states induced by radiation. This means that the trivalent state is not inherent for the bulk of divalent rare earths, and therefore they do not become trivalent.

  19. Rare earths and the balance problem

    OpenAIRE

    Binnemans, Koen; Jones , Peter Tom

    2015-01-01

    Maintaining the balance between the demand by the economic markets and the natural abundance of the rare-earth elements (REEs) in ores constitutes a major challenge for manufacturers of these elements. This is the so-called balance problem (or balancing problem). The ideal situation is a perfect match between the demand and (production) supply of REEs, so that there are no surpluses of any of the REEs. The balance problem implicates that the rare-earth industry has to either find new applicat...

  20. 2007 China Rare Earths Import & Export Analysis and Suggestions (continued)

    Institute of Scientific and Technical Information of China (English)

    Yin Jianhua; Zuo Xichao

    2008-01-01

    @@ 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.

  1. 2011 Review and outlook of China rare earth market

    Institute of Scientific and Technical Information of China (English)

    Zhang Lihua; Bai Jinlong

    2012-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    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

  3. Replacing the Rare Earth Intellectual Capital

    Energy Technology Data Exchange (ETDEWEB)

    Gschneidner, Jr., Karl

    2011-04-01

    The rare earth crisis slowly evolved during a 10 to 15 year period beginning in the mid-1980s, when the Chinese began to export mixed rare earth concentrates. In the early 1990s, they started to move up the supply chain and began to export the individual rare earth oxides and metals. By the late 1990s the Chinese exported higher value products, such as magnets, phosphors, polishing compounds, catalysts; and in the 21st century they supplied finished products including electric motors, computers, batteries, liquid-crystal displays (LCDs), TVs and monitors, mobile phones, iPods and compact fluorescent lamp (CFL) light bulbs. As they moved to higher value products, the Chinese slowly drove the various industrial producers and commercial enterprises in the US, Europe and Japan out of business by manipulating the rare earth commodity prices. Because of this, the technically trained rare earth engineers and scientists who worked in areas from mining to separations, to processing to production, to manufacturing of semifinished and final products, were laid-off and moved to other fields or they retired. However, in the past year the Chinese have changed their philosophy of the 1970s and 1980s of forming a rare earth cartel to control the rare earth markets to one in which they will no longer supply the rest of the world (ROW) with their precious rare earths, but instead will use them internally to meet the growing demand as the Chinese standard of living increases. To this end, they have implemented and occasionally increased export restrictions and added an export tariff on many of the high demand rare earth elements. Now the ROW is quickly trying to start up rare earth mines, e.g. Molycorp Minerals in the US and Lynas Corp. in Australia, to cover this shortfall in the worldwide market, but it will take about five years for the supply to meet the demand, even as other mines in the ROW become productive. Unfortunately, today there is a serious lack of technically trained

  4. Diagnostic study about lanthanides (rare earths)

    International Nuclear Information System (INIS)

    The world situation of rare earths (lanthanides) is evaluated, and a comparison of the Brazilian situation in respect to other countries is established, concerning the following aspects: geology of mineral deposits; main sources, uses, reserves and production; their consumption, prices and state-of-art of geological researches and industrial processes for physical and chemical separation / concentration of these elements. (C.L.B.)

  5. China Not the Only Rare Earth Exporter

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ 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.

  6. Alternative value chains for rare earths

    DEFF Research Database (Denmark)

    Machacek, Erika; Fold, Niels

    2014-01-01

    The 2011 peak in rare earth element (REE) prices revealed a vast knowledge gap on the REE-based industry considered to be almost monopolized by Chinese players. A global value chain (GVC) framework is used to provide an understanding of value-adding segments of REE in their transformation from mine...

  7. Rare earth phosphors and phosphor screens

    International Nuclear Information System (INIS)

    Advances in the use of stabilized rare earth phosphors and of conversion screens using these materials are examined. In particular the new phosphors discussed in this invention consist of oxybromides of yttrium, lanthanum and gadolinium with a luminescent activator ion stabilized by an oxychloride or oxyfluoride surface layer and the conversion screens include trivalent cerium as the activator ion. (U.K.)

  8. Laser selective photoionization of rare earth

    International Nuclear Information System (INIS)

    The IEAv has special interest in the studies of rare earth isotope applications in laser medium and integrated optics. We are starting to work with Ytterbium, Erbium, Dysprosium and Neodymium laser selective photoionization research. In addition, we are starting studies to analyze the possibility of producing selective photoionization departing from ores, using laser ablation as vapor source. (authors)

  9. Effects of Rare Earth Impurities on Photochromic Characteristics of Rare Earth Orthoniobates

    Science.gov (United States)

    Suemune, Yasutaka

    1983-11-01

    Some rare earth orthoniobates, RNbO4, have been found to exhibit photochromic properties ascribed to the formation of color centers. Compounds with rare earths, R, of gadolinium and ytterbium, have been shown to have a particularly long duration of visible coloration after ultraviolet (UV) irradiation at room temperature. Partial substitution of praseodymium or terbium as the rare earths enhances these UV coloration characteristics. Substitution of about 0.8% of terbium is remarkably effective in accelerating the thermal bleaching, increasing the bleaching rate by about one order of magnitude.

  10. Modelling the liquid-liquid extraction of nitric acid and lanthanide nitrates by tributylphosphate. Study of the influence of the aqueous phase composition on the selectivity of rare earth separation

    International Nuclear Information System (INIS)

    This research thesis reports the application of advances in the modelling of liquid-liquid extraction to a quantitative processing of the selectivity of separations. It is here applied to the extraction-based separation of lanthanide nitrates by using the tributylphosphate (TBP) in nitric environment as this system is interesting for industrial applications in hydro-metallurgy of rare earths as well as in the processing of irradiated nuclear fuels. Experimental data are acquired and then used in the Mikulin-Sergievskii-Dannus model. Complete modelling is thus obtained which allowed the complex problem of extraction of nitric acid and of lanthanide to be addressed, and the existence of a hybrid solvate to be supported. A mathematical expression of the separation factor of two lanthanides is proposed and used to highlight its influencing parameters, i.e. water activity in the aqueous phase, and the rate of the effective extraction constants of the two elements to be separated. Experimental observations are thus interpreted. The selection of optimal separation conditions is thus justified, and, in some cases, the system selectivity can be predicted

  11. Separation of rare earth elements by microorganisms

    International Nuclear Information System (INIS)

    The selective accumulation of rare earth elements in Gram-positive bacteria and actinomycetes was examined. The resting cells of 18 strains having high capacities to accumulate rare earth elements were screened for selectivity using a solution containing 5 elements: Y, La, Sm, Er, and Lu. Among the strains tested, Bacillus megaterium accumulated Sm, Streptomyces albus accumulated Lu, and Arthrobacter nicotianae accumulated both Sm and Lu in higher quantities than the other metals. Similar results were also obtained from a solution containing Y and 14 rare elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). The amount of Sm accumulated in B. megaterium and that of Lu accumulated in S. albus increased as the initial metal concentration increased. S. albus and B. megaterium cells show the highest capacity to accumulate Lu and Sm, respectively, from a solution containing 5 elements, Y, La, Sm, Er, and Lu when each metal concentration ranged from 20 to 100 μM. These results suggest that the separation of these two rare earth elements using microorganisms should be possible. (author)

  12. Study on the determination of 14 individual rare earth elements and yttrium in rare earth oxides by inductively coupled plasma mass spectroscopy (ICP-MS)

    International Nuclear Information System (INIS)

    The simultaneous determination of 14 rate earth elements and (Y) in rare earth oxide by inductively coupled plasma mass spectroscopy (ICP-MS) was studied. The rare earth oxide sample was dissolved in nitric acid and the aqueous solution containing 14 rare earth elements and Y was measured on the ICP-MS under the optimum conditions such as: concentration of nitric acid, coolant argon flow rate, sample uptake rate, sampling depth, sample uptake time and other characteristic parameters of instrument. The analytical procedure was set-up and that was applied for the determination of these above-mentioned elements in the rare earth oxide samples by ICP-MS with acceptable precision and accuracy. (author)

  13. Rare earth optogalvanic spectroscopy: preliminary results

    International Nuclear Information System (INIS)

    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)

  14. Sulphide glasses doped with rare earth elements

    Czech Academy of Sciences Publication Activity Database

    Ležal, Dimitrij; Zavadil, Jiří; Procházková, Olga

    Bratislava : Slovak Technical University, 1999, s. 29-31 ISBN 80-8040-098-9. [Applied physics of condensed matter. Kočovice (SK), 23.06.1999-25.06.1999] R&D Projects: GA ČR GA104/99/0342; GA ČR GA102/99/0341 Institutional research plan: CEZ:AV0Z4032918 Keywords : fibre lasers * rare earth elements * sulphide glasses Subject RIV: CA - Inorganic Chemistry

  15. China’s rare earth trade analysis

    OpenAIRE

    Oana Maria STANCULESCU

    2011-01-01

    In current times, eco trend is promoted in all areas, therefore finding alternative energy sources is required. Most modern technology that does not harm the environment is based on different amounts of Dysprosium, Terbium, Neodymium, and so on. Solar panels, wind turbines, hybrid cars and many other electronics such as televisions are using such elements. Respecting the principles of free trade, countries such as Japan or the U.S. imported from China large quantities of rare earth to pursue ...

  16. Phase Behavior of Rare Earth Manganites

    Institute of Scientific and Technical Information of China (English)

    Naoki Kamegashira; Hiromi Nakano; Gang Chen; Jian Meng

    2004-01-01

    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.

  17. Mineralogy of the rare earth elements

    International Nuclear Information System (INIS)

    This paper contains mineralogic properties of the rare earth elements (REE). Notes are given on total REE abundances, distribution patterns, and modes of occurrence. References are confined as far as possible to papers containing usable REE data. The minerals are grouped alphabetically within each major cationic group. The paper includes an alphabetic table of mineral names, chemical formulas, crystal system and section number. It functions as a handy entrance to the mineralogic and bibliographic paper. (G.J.P.)

  18. Rare earths in ceramic materials technology

    International Nuclear Information System (INIS)

    Rare earth elements are mainly exploited for electronic devices, but far from negligible is their importance in materials for structural applications, i.e. for their mechanical properties, useful in modern technologies. For example, widely renown is the role of rare earth oxides in the study of zirconia (zirconium dioxide, ZrO2), by far the most interesting ceramic material for structural applications. Among rare earth oxides, ceria (cerium dioxide, CeO2) has played a fundamental role because at room temperature it stabilizes the tetragonal phase of zirconia, which is the most interesting phase from a mechanical point of view. In this presentation the main characteristics of the system CeO2-ZrO2 are outlined, along with the mechanical properties of binary alloys of the two oxides; these properties are evaluated as a function of their composition and microstructure. Some of these alloys exhibited behaviour completely unexpected for ceramic materials, e.g. the Shape Memory Effect (SME) and the Gorsky Effect. (orig.)

  19. Anthropogenic Cycles of Rare Earth Elements

    Science.gov (United States)

    Du, X.; Graedel, T. E.

    2009-12-01

    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

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

    Institute of Scientific and Technical Information of China (English)

    Nilanjana Das; Devlina Das

    2013-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    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.

  2. Reduction property of rare earth oxide doped molybdenum oxide

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    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.

  3. Distribution of rare earths in liver of mice administered with chloride compounds of 12 rare earths

    International Nuclear Information System (INIS)

    Full text: Rare earths are used in high technology field, however, the information on their biological effects are not sufficient. The behaviour of rare earths in biology is of interest in connection with their toxicity. In the present study, the distribution of rare earths in liver of mice administered with these elements was investigated. The effects on Ca and other biological essential elements were also determined. Male mice (5 weeks old) were injected with one of 12 kinds of rare earths (chlorides of Y, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb) at the dose of 25 mg/KXg body weight. After 20 hours of administration, mice were sacrificed, then liver and other organs were taken out. Liver was homogenized and separated by centrifugation. The concentrations of rare earths administered were measured by microwave-induced plasma-mass spectrometry (MIP-MS) after acid digestion. The concentrations of administered elements in whole liver were about 100μg/g (wet weight), where the difference between elements was few. Distribution amounts of elements administered in four fractions were following order; 700μg precipitate > mitocondrial fraction > microsomal fraction > cytosol. The relative contents in these fractions, however, was different depending on the element administered. Calcium concentrations in liver of administered mice were higher than those of control mice. Increase of Ca concentrations were observed in all four fractions and the increase ratio was also dependent on the elements administered

  4. Rare earth elements materials production from apatite ores

    Science.gov (United States)

    Anufrieva, A. V.; Andrienko, O. S.; Buynovskiy, A. S.; Makaseev, Y. N.; Mazov, I. N.; Nefedov, R. A.; Sachkov, V. I.; Stepanova, O. B.; Valkov, A. V.

    2016-01-01

    The paper deals with the study of processing apatite ores with nitric acid and extraction of the rare earth elements. The rare earth elements can be successfully separated and recovered by extraction from the nitrate- phosphate solution, being an tributyl phosphate as extraction agent. The developed scheme of the processing apatite concentrate provides obtaining rare earth concentrates with high qualitative characteristics.

  5. Rare earth elements behavior in Peruibe black mud

    International Nuclear Information System (INIS)

    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)

  6. Guangdong to Build a Rare Earth Industry Chain

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>On February 27,Guangdong Rare Earth Industry Group(GREIG),which is China’s first large group spanning the whole rare earth industry chain,was set up in Guangzhou.Since the State Council put forward the largeenterprise(group) strategy for the rare earth

  7. ESR investigations of some rare earth pseudo binary intermetallic compounds

    International Nuclear Information System (INIS)

    The author presents the results of an electron spin resonance study on several rare earth-Be13 compounds, the Au: Er alloy system, and Nd3+ and Gd3+ in rare earth-Rh2 and rare earth-Ir2 cubic Laves phase compounds. (G.T.H.)

  8. 40 CFR 721.6005 - Rare earth phosphate (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Rare earth phosphate (generic). 721... Substances § 721.6005 Rare earth phosphate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified generically as rare earth phophate (PMNs...

  9. Stuffed rare earth pyrochlore solid solutions

    International Nuclear Information System (INIS)

    Synthesis and crystal structures are described for the compounds Ln 2(Ti2-xLnx )O7-x/2, where Ln=Tb, Dy, Ho, Er, Tm, Yb, Lu, and x ranges from 0 to 0.67. Rietveld refinements of X-ray powder diffraction data indicate that in the Tb and Dy titanate pyrochlores, the extra Ln 3+ cations mix mainly on the Ti4+ site with little disorder on the original Ln 3+ site. For the smaller rare earths (Ho-Lu), stuffing additional lanthanide ions results in a pyrochlore to defect fluorite transition, where the Ln 3+ and Ti4+ ions become completely randomized at the maximum (x=0.67). Initial magnetic characterization for the fully stuffed x=0.67 samples for Ln=Tb-Yb shows no long range ordering down to 2 K, and only partial saturation of the full expected magnetic moment under applied fields up to 5 T. In all of these Ln-Ti-O pyrochlores, the addition of magnetic Ln 3+ in place of non-magnetic Ti4+ adds edge sharing tetrahedral spin interactions to a normally corner sharing tetrahedral network of spins. The increase in spin connectivity in this family of solid solutions represents a new avenue for investigating geometrical magnetic frustration in the rare earth titanate pyrochlores. - Graphical abstract: A simplified model of the transition from pyrochlore to fluorite in the series Ln 2(Ti2-xLnx )O7-x/2 (Ln=Tb-Lu, 0≤x≤0.67), with Ho as an example. The separate corner sharing tetrahedral lattices of cations in the pyrochlore structure develop into edge sharing tetrahedra as extra Ln is stuffed in place of Ti. The increased spin connectivity in these new materials represents a new avenue of study in the well-known rare earth titanate pyrochlores in view of geometrical magnetic frustration

  10. Port Pirie rare earths plant stage 3

    International Nuclear Information System (INIS)

    SX Holdings Limited intends to establish a rare earths plant at Port Pirie, South Australia. The proposal involves three stages of development, Stage 3 being to develop a monazite cracking plant and associated rare earths separation facility with the capacity to process up to 8,000 t/a of monazite-type ores. The proposed initial capacity is 4,000 t/a. This Draft Environmental Impact Statement relates to Stage 3 and is based on a monazite processing capacity of 8,000 t/a. The justification of the project is given in terms of use and the market for rare earths, the economic and environmental benefits of the proposal, the site selection process, site rehabilitation, and the consequences of not proceeding. A detailed description of the project is given, including the treatment process, site development and facilities, the supply of raw materials, product and waste handling, transport and storage, plant commissioning, operation and decommissioning, construction and staffing. The environmental issues entailed in the proposed development are discussed and include social effects, land use and infrasturcture considerations, risk management and transport. Occupational and environmental radiation issues, including assessments of exposure pathways and doses, management and monitoring, disposal of monosite residue are also discussed. It is estimated that the effects of disposal of 2,330 t/year of radioactive slurry in the sub-aerial tailing disposal system at Olympic Dam will be negligible. Moreover, the gamma dose increases would not result in any significant increase in occupational exposures. 38 refs., tabs., ills

  11. Coriolis attenuation in the rare earth region

    International Nuclear Information System (INIS)

    It is shown that the observed rotational band structure in a number of odd-proton and odd-neutron nuclei situated in the rare earth region, can be reproduced in the particle-rotor model without any ad hoc reduction of the Coriolis matrix elements if a value of the pairing gap parameter, which is about 30-40% of that deduced from the corresponding odd-even mass difference, is used. The importance of the proper choice of the pairing gap parameter in the study of the Coriolis attenuation problem is emphasised. (orig.)

  12. Raman investigations of rare earth orthovanadates

    Science.gov (United States)

    Santos, C. C.; Silva, E. N.; Ayala, A. P.; Guedes, I.; Pizani, P. S.; Loong, C.-K.; Boatner, L. A.

    2007-03-01

    Polarized Raman spectroscopy has been used to obtain the room-temperature phonon spectra of the series of rare earth orthovanadate single crystals: SmVO4, HoVO4, YbVO4, and LuVO4. The observed Raman frequencies follow the overall mode distribution expected for REVO4 compounds with the tetragonal zircon structure. The variation of the mode frequency with atomic number across the lanthanide orthovanadate series was investigated, and the trend exhibited by the internal modes was explained by considering the force constants of VO4 tetrahedron.

  13. Raman Investigations of Rare-Earth Orthovanadates

    Energy Technology Data Exchange (ETDEWEB)

    Santos, C. C. [Universidade Federal do Ceara, Ceara, Brazil; Silva, E. N. [Universidade Federal do Ceara, Ceara, Brazil; Ayala, A. P. [Universidade Federal do Ceara, Ceara, Brazil; Guedes, I. [Universidade Federal do Ceara, Ceara, Brazil; Pizani, P. S. [Universidade Federal de Sao Carlos, Caixa Postal, Brazil; Loong, C. K. [Argonne National Laboratory (ANL); Boatner, Lynn A [ORNL

    2007-01-01

    Polarized Raman spectroscopy has been used to obtain the room-temperature phonon spectra of the series of rare earth orthovanadate single crystals: SmVO4, HoVO4, YbVO4 and LuVO4. The observed Raman frequencies follow the overall mode distribution expected for RVO4 compounds with the tetragonal zircon structure. The variation of the mode frequency with atomic number across the lanthanide orthovanadate series was investigated, and the trend exhibited by the internal modes was explained by considering the force constants of VO4 tetrahedron.

  14. Characterization of a rare earth oxide obtained from xenotime mineral

    International Nuclear Information System (INIS)

    This paper reports on the characterization of a rare earth oxide obtained by hydrometallurgy of the mineral xenotime, an yttrium phosphate containing other rare earths, and comparison with mixtures of rare earth oxides prepared in different ways. The results indicated that hydrometallurgy from xenotime yielded a solid solution of the rare earth oxides. However, when the pure rare earth oxides were simply mixed physically then heat-treated at 1000 deg. C, a similar solid solution was not obtained. On the other hand, when the mixtures were prepared using a co-precipitation process, subsequent heat treatment did produce oxide solid solutions similar to that produced by hydrometallurgy of xenotime

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Imashuku, Susumu, E-mail: imashuku.susumu.2m@kyoto-u.ac.jp; Fuyuno, Naoto; Hanasaki, Kohei; Kawai, Jun [Department of Materials Science and Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan)

    2013-12-15

    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.

  17. Thermoelectric transport in rare-earth compounds

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, Ulrike

    2007-07-01

    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.)

  18. Photoelectron spectra of rare earth acetylacetonates

    International Nuclear Information System (INIS)

    By the method of gaseous photoelectron spectroscopy electron structure of rare earth acetylacetonates, prepared by means of thermolysis in spectrometer of the corresponding MA3·Q adducts (Q=DMSO, HMPA), has been studied. From yttrium series compounds only for Y, Dy, Ho, Er, Lu derivatives the spectra do not contain the bands of decomposition product-acetone. Out of three studied compounds of cerium groups (M=La, Sm, Nd) only for LaA3 the attempt to record photoelectron spectrum has failed. In the first three bands of all the compounds a-e-splitting is detected, which is caused by the contribution of metal AO to molecular orbital. The greatest splitting is characteristic for n--electrons of ScA3 and LuA3. Increase in ionization energy of Π3-- and n--electrons with an increase in rare earth ordinal number is caused by lanthanide compression and constitutes 0.2-0.3 eV

  19. Thermoelectric transport in rare-earth compounds

    International Nuclear Information System (INIS)

    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 Ce3Rh4Sn13 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 Lu1-xYbxRh2Si2 and CexLa1-xNi2Ge2 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.)

  20. Processing of monazite at the rare earth division,Udyogamandal

    International Nuclear Information System (INIS)

    The processing techniques adopted at the Rare Earth Division of the Indian Rare Earths Limited at Udyogamandal, for the production of rare earth compounds of various compositions and purity grades are reviewed. Over 100 different compounds are produced and marketed, and these include mixed rare earths chloride, crude thorium concentrate, cerium oxide, cerium hydrate, rare earths carbonate, didymium salts and individual rare earth oxides and salts. Also, the trisodium phosphate obtained as byproduct in the processing of monazite, is recovered and marketed. The process scheme for monazite essentially involves alkaline digestion of ground monazite, removal of the by-product trisodium phosphate, separation of thorium through preferential dissolution of rare earths hydroxide in hydrochloric acid under controlled pH and temperature conditions followed by purification, and evaporation of the chloride solution to yield pure rare earths chloride. Part of the chloride is utilised for the production of individual rare earth compounds after separation by solvent extraction and ion exchange processes. Individual rare earth compounds of 99.99 %+ purity are regularly produced to cater to the demand within the country. (author) 8 figs., 1 tab

  1. Preparation and characterization of nano rare earths

    Energy Technology Data Exchange (ETDEWEB)

    Song Xiaoyan; Lu Nianduan; Liu Xuemei; Lu Qingmei; Zhang Jiuxing; Zhou Meiling [School of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Chinese Ministry of Education, Beijing University of Technology, Beijing 100022 (China); Sun Lixian [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Rettenmayr, Markus [Institute of Materials Science and Technology, Friedrich-Schiller-University Jena, D-07743 Jena (Germany); Yin Fuxing [National Institute for Materials Science, Sengen 1-2-1, Tsukuba 305-0047 (Japan)], E-mail: xysong@bjut.edu.cn

    2008-02-15

    Rare earth (RE) nanoparticles with single-crystal structure and controllable size, and RE nanocrystalline bulks with ultrafine grain sizes (3-8 nm), were prepared with a home-configured 'oxygen-free' in situ synthesis system. Systematic investigations revealed the characteristic structures and properties of the nano REs. As compared with the conventional polycrystalline REs, the prepared ultrafine nanocrystalline REs show remarkably different physical, thermal and mechanical properties, which are of broad scientific and engineering interest. The series of structure and property characterizations are significant to further develop the fundamental database for the nano REs. As a particular contribution to the characterization of the RE family on the nanoscale, this work implements a clear guideline for the composition design and the scale control in the development of advanced nano RE functional and structural materials.

  2. Preparation and characterization of nano rare earths

    International Nuclear Information System (INIS)

    Rare earth (RE) nanoparticles with single-crystal structure and controllable size, and RE nanocrystalline bulks with ultrafine grain sizes (3-8 nm), were prepared with a home-configured 'oxygen-free' in situ synthesis system. Systematic investigations revealed the characteristic structures and properties of the nano REs. As compared with the conventional polycrystalline REs, the prepared ultrafine nanocrystalline REs show remarkably different physical, thermal and mechanical properties, which are of broad scientific and engineering interest. The series of structure and property characterizations are significant to further develop the fundamental database for the nano REs. As a particular contribution to the characterization of the RE family on the nanoscale, this work implements a clear guideline for the composition design and the scale control in the development of advanced nano RE functional and structural materials

  3. Ecological effect of rare earth elements

    International Nuclear Information System (INIS)

    Water and soil culture were carried out to study the ecological effect of rare earth elements (REEs) in the aspect of plant-soil system. Contents of REEs were determined by instrumental neutron activation analysis (INAA). There was a limit to REEs-tolerance of crops, which differed with the development periods of plant and soil types. The REEs concentration in plant, especially in root, was marked related to the concentration in culture material. Beyond the concentration-limit appeared phototoxicity. The chemical behavior of REEs in plants and soils varied with soil types and elements. The bio-availability of REEs in soil mainly depended on the exchangeable fraction of REEs affected strongly by the physi-chemical properties of soils

  4. Octupole vibrations in rare-earth nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Buessing, Marc Andre; Elvers, Michael; Endres, Janis; Hasper, Jens; Zilges, Andreas [Institut fuer Kernphysik, Universitaet Koeln, D-50823 Koeln (Germany)

    2009-07-01

    The systematics of octupole vibrations in the region of rare-earth nuclei are still not well understood. First test measurements have been carried out at the FN Tandem accelerator of the University of Cologne. The gamma-ray spectroscopy was performed at the highly-efficient HORUS spectrometer which consists of 16 High-Purity Germanium detectors. The nucleus {sup 158}Dy has been investigated via the reactions {sup 156}Gd({alpha},2n) and {sup 149}Sm({sup 12}C,3n), furthermore the nucleus {sup 154}Dy was studied via the reaction {sup 144}Nd({sup 14}N,4n). In addition measurements with the (p,p{sup '}) reaction were carried out on the nuclei {sup 142}Nd and {sup 172}Yb. First results of these measurements are shown in the context of existing data for this mass region.

  5. Production of rare earth polishing powders in Russia

    International Nuclear Information System (INIS)

    in a suspension; polishing powder Ftoropol with addition of fluorine and higher contents of cerium dioxide (at least 70% by mass) that has a higher polishing ability and is attrition-proof, used for high-speed treatment of optical lenses, mirrors, TV screens and eyeglasses. The rare earth polishing powders made in Russia possess the following physico-chemical properties and performance characteristics; cerium dioxide content in solid REE solution - 50-90% by mass; F-ion content (in Ftoropol powder) - 8-14% by mass; non-REE content of sodium, calcium, strontium and iron impurities - at most 0.1% by mass of each element; natural radionuclide content of thorium, uranium, actinium, potassium-40 series, total standard specific activity - 0.45-0.85 Bq/g; - average particle size, 2.0-3.5 μm; density - 6.3-6.8 g/cm3; pH of aqueous extract, 6-7; sedimentary stability - 10-20 minutes; polishing ability - 45-60 mg per 31 minutes (for polishing resin); abrasive inclusions - none. The report gives analysis of the. Russian powders compared against the best world analogues such as Cerox (Rhone Poulenc Company, France), Regipol (London and Scandinavian Division Chemical Company, England), etc. The analysis results imply, that the chief characteristics (granulometric composition, polishing ability and service life) of the Russian samples do not yield to the best foreign analogues, and in some properties (radionuclide content, sedimentary stability and scratching inclusions quantity) even surpass them

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

    Institute of Scientific and Technical Information of China (English)

    许涛; 彭会清

    2009-01-01

    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 ...

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

    Institute of Scientific and Technical Information of China (English)

    SONG Hongfang; HONG Mei

    2011-01-01

    @@ 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.

  8. Enhanced pinning in mixed rare earth-123 films

    Science.gov (United States)

    Driscoll, Judith L.; Foltyn, Stephen R.

    2009-06-16

    An superconductive article and method of forming such an article is disclosed, the article including a substrate and a layer of a rare earth barium cuprate film upon the substrate, the rare earth barium cuprate film including two or more rare earth metals capable of yielding a superconductive composition where ion size variance between the two or more rare earth metals is characterized as greater than zero and less than about 10.times.10.sup.-4, and the rare earth barium cuprate film including two or more rare earth metals is further characterized as having an enhanced critical current density in comparison to a standard YBa.sub.2Cu.sub.3O.sub.y composition under identical testing conditions.

  9. Extraction of rare earths and hydrochloric acid by trialkylphosphine oxide

    International Nuclear Information System (INIS)

    Extraction of rare earth chlorides and hydrochloric acid by trialkylphosphine oxide with different radicals (POR) (RR'2PO-POR, where RR'=alkyl of a normal structure, containing 7 to 9 carbon atoms, R=isoamyl) has been studied. Distribution of lanthanum-, neodymium-, lutetium- and yttrium chlorides during extraction with 1.28 mol/l POR solution in white spirit is investigated in the salt concentration range in the equilibrium aqueous phase from 0 to 2.8 mol/l. Lanthanide distribution coefficients increase with an increase in the order number of elements, with the separation coefficients of two extreme members of the series (Lu and La) for chlorides and nitrates constituting 100 and 80, respectively microquantities of Ln against the background of macroquantities of La is 2.6 mol/l. According to the results of measurements of viscosity, electric conductivity and water content in the extracts a conclusion is made on the state of salt in the organic phase. In the systems POR-LnCl3-HCl-H2O the hydrochloric acid extraction increases with an increase in the rare earth chloride concentration and order number of the element

  10. Fabrication of Superhydrophobic and Luminescent Rare Earth/Polymer complex Films.

    Science.gov (United States)

    Wang, Zefeng; Ye, Weiwei; Luo, Xinran; Wang, Zhonggang

    2016-01-01

    The motivation of this work is to create luminescent rare earth/polymer films with outstanding water-resistance and superhydrophobicity. Specifically, the emulsion polymerization of styrene leads to core particles. Then core-shell-structured polymer nanoparticles are synthesized by copolymerization of styrene and acrylic acid on the core surface. The coordination reaction between carboxylic groups and rare earth ions (Eu(3+) and Tb(3+)) generates uniform spherical rare earth/polymer nanoparticles, which are subsequently complexed with PTFE microparticles to obtain micro-/nano-scaled PTFE/rare earth films with hierarchical rough morphology. The films exhibit large water contact angle up to 161° and sliding angle of about 6°, and can emit strong red and green fluorescence under UV excitation. More surprisingly, it is found that the films maintain high fluorescence intensity after submersed in water and even in aqueous salt solution for two days because of the excellent water repellent ability of surfaces. PMID:27086735

  11. Towards the development of rare earth free permanent magnets

    International Nuclear Information System (INIS)

    At present, the conventional rare earth hard magnets have dominated the market and Fe-Nd-B is the most efficient class of permanent magnets. The rare earth crisis in recent decades has led to find an alternative to present day hard magnetic materials. The ferrimagnetic Fe3Se4 with large uniaxial magnetocrystalline anisotropy is a potential low cost candidate for rare earth free permanent magnet. Fe3Se4 nanocrystals were synthesized by a simple hot colloidal method

  12. Analysis and Outlook of Global Rare Earth Market

    Institute of Scientific and Technical Information of China (English)

    XIONG Jiaqi

    2008-01-01

    @@ 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.

  13. Mechanism of Rare Earth Incorporation and Crystal Growth of Rare Earth Containing Type-I Clathrates

    Science.gov (United States)

    2015-01-01

    Type-I clathrates possess extremely low thermal conductivities, a property that makes them promising materials for thermoelectric applications. The incorporation of cerium into one such clathrate has recently been shown to lead to a drastic enhancement of the thermopower, another property determining the thermoelectric efficiency. Here we explore the mechanism of the incorporation of rare earth elements into type-I clathrates. Our investigation of the crystal growth and the composition of the phase Ba8–xRExTMySi46–y (RE = rare earth element; TM = Au, Pd, Pt) reveals that the RE content x is mainly governed by two factors, the free cage space and the electron balance. PMID:26823658

  14. Chemical bond properties of rare earth ions in crystals

    International Nuclear Information System (INIS)

    By using the dielectric description theory of ionicity of solids, chemical bond properties of rare earth ions with various ligands are studied. Calculated results show that chemical bond properties of the same rare earth ion and the same ligand in different crystals depend on the crystal structures. In a series of compounds, chemical bond properties of crystals containing different rare earth ions are similar. The magnitude of covalency of chemical bonds of trivalent rare earth ions and various ligands has an order like F< Cl< Br< As< Sb. (orig.)

  15. Storing Solar Energy Performance on Rare Earth Windowpane

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

    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.

  16. Epoxide polymers containing coordinated ions of rare earth elements

    International Nuclear Information System (INIS)

    Polymerization of phosphorus-containing glycidyl ester mixed with rare earth salts (rare earths = La, Pr, Nd, Gd - Lu, Y, Sc) at different ratios of components in the temperature range of 40 - 80 Deg C was studied for preparation of polymers with a high content of rare earths. The polymers prepared were characterized by the methods of electron and IR spectroscopy and thermomechanics. It was ascertained that solid optically transparent polymers containing up to 25 wt. % of coordinate-bound rare earth ions can be prepared using the method described

  17. Rare earth impact on glass structure and alteration kinetics

    International Nuclear Information System (INIS)

    This work is related to the question of the geological deep repository of high-level waste glass. These wastes include fission products and minor actinides, elements which can be simulated by rare earths. As new glass compositions could enable increased rare earth concentrations, it is crucial to know and understand rare earth impact on glass structure on the one hand, and on glass alteration kinetics or their incorporation into an altered layer. This work studied simplified borosilicate glasses in order to limit synergetic effects between rare earths and other elements. Various complementary techniques were used to characterize pristine and altered glasses (solid-high resolution NMR, Raman spectroscopy, fluorescence, SIMS, SAXS). Firstly, the structural role of a rare earth is discussed and is compared to a calcium cation. The local environment of rare earths is also probed. Secondly, rare earth (nature and concentration) impact on several alteration regimes was studied (initial rate, rate drop). Then, after alteration, rare earth elements being retained within the altered layer, the structural impact of rare earth elements (and their local environment) in this alteration layer was also investigated. (author)

  18. Mechanism of Rare Earth Incorporation and Crystal Growth of Rare Earth Containing Type-I Clathrates

    OpenAIRE

    Prokofiev, Andrey; Svagera, Robert; Waas, Monika; Weil, Matthias; Bernardi, Johannes; Paschen, Silke

    2015-01-01

    Type-I clathrates possess extremely low thermal conductivities, a property that makes them promising materials for thermoelectric applications. The incorporation of cerium into one such clathrate has recently been shown to lead to a drastic enhancement of the thermopower, another property determining the thermoelectric efficiency. Here we explore the mechanism of the incorporation of rare earth elements into type-I clathrates. Our investigation of the crystal growth and the composition of the...

  19. Complex formation constant and hydration number change of aqua-rare earth ions

    International Nuclear Information System (INIS)

    Full text: It is now well established that the inner-sphere hydration number of aqua-rare earth ions changes from nine to eight in the middle of the rare earth series. This hydration number change greatly affects the complex formation of rare earth ions as we observe irregular variations in most series behaviours of the complex formation constant (K) in aqueous solution systems when K being plotted against 1/r or r (r is ionic radius of rare earth ion). Furthermore, it shows very anomalous concentration dependence in the sense that nona-aqua Ln3+ ion increases in number with increase in salt concentration in aqueous rare earth salt solution (salt chloride, perchlorate). In this report, a theoretical derivation of the formation constant (K) for the inner-sphere complex formation of rare earth ions with a monodentate ligand was made by taking account of both the hydration number change in the middle of the series and its anomalous salt concentration dependence. The series behaviour of the formation constant against 1/r (or r) is successfully explained with using the empirical finding that K varies almost linearly with 1/r (or r) in the region where only one hydration number dominates. This success is also taken as evidence that the anomalous salt concentration dependence of the hydration number change is caused by the outer-sphere complex formation of rare earth ions with the condition that nona-aqua rare earth ions form outer-sphere complexes more easily than octa-aqua ions

  20. Rare earth silicide nanowires on silicon surfaces

    International Nuclear Information System (INIS)

    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 Γ 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 DySi2-monolayer and the Dy3Si5-multilayer on the Si(111) surface are investigated in comparison to the known ErSi2/Si(111) and Er3Si5/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 parallel space is elliptical at the anti M points, while the hole pocket at the anti Γ 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 of the sample surface, which are oriented in the same

  1. Improved Rare-Earth Emitter Hollow Cathode

    Science.gov (United States)

    Goebel, Dan M.

    2011-01-01

    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

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

    Indian Academy of Sciences (India)

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

    2012-03-01

    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.

  3. Barocaloric effect in rare earth compounds

    Science.gov (United States)

    Antunes de Oliveira, Nilson

    2014-03-01

    The magnetic barocaloric effect, which is characterized by the isothermal entropy change and adiabatic temperature change upon pressure variation can be a very useful to improve the performance of magnetic refrigerator. In this work, we discuss the barocaloric effect in rare earth compounds. To this end we use a model of interacting localized magnetic moments. In the first part of the work we make a systematic analysis in terms of the model parameters, considering the simplest case whose angular momentum is 1/2. Our calculations show that the behavior of the barocaloric quantities can be normal, inverse or anomalous. In the second part of the work, we apply the model to describe the barocaloric effect in the compounds RCo2, Gd5Si2Ge2 and Tb5Si2Ge2. Our theoretical calculations for Gd5Si2Ge2 is in a reasonable agreement with the available experimental data. Our calculations for the other compounds, need experimental data to be confirmed. CNPq, FAPERJ

  4. Ultrasonic attenuation in rare-earth monoarsenides

    Indian Academy of Sciences (India)

    BHALLA VYOMA; SINGH DEVRAJ; JAIN S K; KUMAR RAJ

    2016-06-01

    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.

  5. Weed Seed Labelling with Rare Earth Elements

    International Nuclear Information System (INIS)

    The dormancy period of weed seed under field conditions so far could not be determined with reliability because of the lack of a suitable method for labelling seed. Rademacher and co-workers labelled weed seed with 35S for studying germination in relation to different methods of soil cultivation. Since 35S has a half-period of 87.1 d only, labelling is practically ineffective after one year. The authors of this paper therefore tried to label weed seed with lanthanum, europium and dysprosium. Since these elements (1) do not occur in the standard soils in interfering quantities, and (2) can easily be determined by neutron activation analysis, they are useful for non-radioactive labelling. In pot experiments they were added like fertilizers before the soil was seeded with Sinapsis alba or Vicia villosa. After harvesting, samples of the plants' roots, stems, leaves, and seed were irradiated in the reactor and the rare earth elements determined by neutron-activation analysis. Evaluation of the results disclosed that traceable quantities of lanthanum, europium, and dysprosium were present in roots, stems, and leaves, but not in the grains of seed. It is the intention, in further experiments, to increase the concentration of the applied elements up to the limit of compatibility, and to find out whether a more concentrated supply will increase the incorporation in seeds. If one of these elements is present in a reasonable concentration, experiments with labelled weed seed will be possible for periods of several years. (author)

  6. Magnetic properties of rare earth iron compounds

    International Nuclear Information System (INIS)

    In this thesis, a study is made of hyperfine interactions in the intermetallic compounds Rsub(x)Fesub(y) (R = rare earth, Y or Th) by using the Moessbauer effect in the 57Fe nucleus. The hyperfine interactions in two series of Rsub(x)Fesub(y) compounds, for which Ysub(x)Fesub(y) and Ersub(x)Fesub(y) were chosen, are studied. Thus a comparison can be made between the magnetic properties of compounds with diamagnetic yttrium and ferromagnetic erbium, respectively. In addition, the magnetic anisotropy of these compounds Ysub(x)Fesub(y) and Ersub(x)Fesub(y) has been investigated. The major part of this thesis concerns a study of the R2Fe17 intermetallic compounds. Since Co or Ni substitution for Fe in R2Fe17 compounds results in a fast increase of the Curie temperature, some pseudobinary R2Fesub(17-x)Msub(x) compounds with R = Tm and Er and M = Co and Ni, have been investigated. ThFe5 has been studied, since it is the only known existing RFe5 compound with a crystal structure which is closely related to that of Th2Fe17

  7. Rare-earth-doped fluorozirconate fiber lasers

    International Nuclear Information System (INIS)

    Rare-earth-doped fiber lasers fabricated using silica-based fibers are rapidly becoming an established technology. Simultaneously, in the search for lower losses to achieve longer repeaterless communications links, another fiber technology based on fluorozirconate glasses is emerging. Fluorozirconate glass systems are known to be suitable laser hosts, and the authors have already reported Nd-doped fiber lasers using this technology. Recently the authors have used a 0.5-m length of 44-μm core fluorozirconate fiber doped with 1000 ppm of Nd3+ ions in a longitudinally pumped Fabry-Perot cavity with a 90% output coupler. They observed lasing at 1.05 μm with a threshold of 33-mW launched power at 514 nm and a slope efficiency of 16.8%. The authors attribute this improvement to the higher dopant concentration, better fiber to mirror coupling, and more optimum output coupler reflectivity. In addition the same fiber used with two high-reflector mirrors at 1.35μm produced lasing at 1.35μm with a threshold of 60-mW launched power

  8. Rare earth elements: Yttrium and higher plants

    Directory of Open Access Journals (Sweden)

    Kastori Rudolf R.

    2010-01-01

    Full Text Available Rare earth elements (REEs form a chemically uniform group with very similar physical and chemical properties. The REEs include the elements scandium, yttrium, and the lanthanides from lanthanum to lutetium. They are widely distributed and present in all parts of the biosphere. REEs are required in industry, agriculture, medicine, biotechnology, environmental problems and many other fields. Lately, many experiments show their positive or negative, first of all nonspecific, effect on life processes of higher plants as well as growth and yield of cultivated species, but the physiological mechanisms are still not well understood. It has been determined that yttrium is widely distributed in plants, as well as that certain plant species uptake yttrium at different extent. Its highest accumulation is in the root and the leaf. Although yttrium was discovered more than two centuries ago, its effect on higher plants - their anatomical and morphological built, physiological and biochemical processes etc. - is very little known. One of the basic reasons is that yttrium, as well as other REEs elements, according to current knowledge, is not biogenic for higher plants and - wider - for live organisms. The objective of this paper is to concisely show previous knowledge about yttrium in the plant world.

  9. Current situation and outlook of China rare earth industry (continued)%Current situation and outlook of China rare earth industry (continued)

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    (1) Regional rare earth economy basically formed and consolidation of rare earth industry is progressing steadily Baotou Steel Rare Earths has consolidated the rare earth industry in Inner Mongolia and Northern Rare Earth Group led by Baotou Steel (Group) Company has been established. Consolidation Work Plan for Upstream Enterprises in Inner Mongolia Autonomous Region was announced on May 4, 2011. Based on the document, except Baotou Steel Rare Earths, total 35 companies (5 in Huhhot,

  10. MBE growth and characterisation of light rare-earth superlattices

    DEFF Research Database (Denmark)

    Ward, R.C.C.; Wells, M.R.; Bryn-Jacobsen, C.;

    1996-01-01

    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...

  11. Method of producing a ductile rare-earth containing superalloy

    International Nuclear Information System (INIS)

    A method is provided for producing ductile superalloys containing rare-earth metals, lanthanum, and yttrium by melting the desired alloy composition by conventional melt practices, adding the rare-earth metals, lanthanum or yttrium to the molten composition, forming the alloy composition into solid electrodes, remelting the solid electrode by electroslag remelting, techniques and casting the remelted alloy

  12. Energy transfer processes in rare-earth compounds

    International Nuclear Information System (INIS)

    In this thesis the results are described of an investigation into the radiationless transfer of electronic excitation energies in various Eu3+ and Tb3+ compounds, which show structural peculiarities in the rare-earth sublattice. These peculiarities are an one-dimensional sublattice as well as two different crystallographic locations for the rare-earth ion. 154 refs.; 43 figs.; 12 tabs

  13. Imports εt Exports Review of Chinese Rare Earths

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ 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.

  14. Separation of rare earths from solutions of phosphoric acid

    International Nuclear Information System (INIS)

    Rare earths are separated from 6M phosphoric acid by adsorption onto cation resin BIORAD AG50W-X8. The phosphoric acid is then washed from the column, and the rare earths are eluted with 4M hydrochloric acid

  15. Review and outlook of 2008 China rare earth market

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lihua

    2009-01-01

    @@ 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.

  16. Determination of active oxygen content in rare earth peroxides

    International Nuclear Information System (INIS)

    The content of active oxygen in rare earth peroxides have been determined after the dissolution of the samples with hydrocloridic acid in the presence of potassium iodide. The free generated iodine is titrated with sodium thiosulfate using starch as indicator. The oxidation of iodide to the free iodine indicates the presence of a higher valence state rare earth oxide, until now specifically recognized for the oxides of cerium (Ce O2), praseodymium (Pr6 O11) and terbium (TB4 O7). recently the authors synthesized a new series of rare earth compounds, the peroxides. These new compounds were prepared by precipitating the rare earth elements complexed with carbonate ion by addition of hydrogen peroxide. the authors demonstrated that all rare earth elements, once solubilized by complexing with carbonate ion, are quantitatively precipitated as peroxide by addition of hydrogen peroxide. (author)

  17. Rare earth resources development and its NORM radiation protection

    International Nuclear Information System (INIS)

    There is growing demand for rare earth elements as raw materials for industrial goods such as high performance magnet. Thus, rare earth resources attract a lot of strategic attention internationally. The rare earth ore often contains uranium and thorium, that are Naturally Occurring Radioactive Material (NORM). Usually, such radioactive substances almost remain in the waste yielded in the extraction process for rare earth elements. Therefore, radiation protection is required in all of operation phases from mining and refining to waste disposal, and it is appropriate to the purpose to use the reference level of intervention in the ICRP recommendation. To ensure resource development, it is important that sites where wastes were disposed of are reused under monitored natural attenuation of the chemical conditions of the wastes after early physical stabilization of the land. This paper illustrates current status of rare earth development along with related radiation protection issue. (author)

  18. Rare earth silicide nanowires on silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wanke, Martina

    2008-11-10

    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

  19. Fluoride solid electrolytes containing rare earth elements

    Institute of Scientific and Technical Information of China (English)

    Viera Trnovcová; Pavel P. Fedorov; Ivan Furár

    2008-01-01

    Relations between the structure, ionic conductivity and dielectric properties of fluoride systems of different structures containing rare earth elements were presented. Superionic conductivities, by fluoride ions, of fluorite-structured (MF2-REF3, M=Ba, Pb, RE=La-Lu, Sc, Y), orthorhombic (REF3, RE=Tb-Er,Y), tysonite-structured (REF3-MF2, RE=La-Nd, M=Sr), monoclinic (BaRE2F8, RE=Ho-Yb, Y) fluoride single crystals and eutectic composites (LiF-REF3, RE=La-Gd,Y) were compared. Anisotropy of electrical properties of crystals with a lower symmetry was explained by modeling optimum ionic paths. For explanation of concentration dependences of fast ionic conductivity, models of aggregation of defects into clusters were proposed. In fluorite-structured crystals, the highest ionic conductivity was found for PbF2: 7 mol% ScF3 (at 500 K, σ500=0.13 S/cm). In tysonite-structured crystals, the highest ionic conductivity was found for LaF3: 3 mol% SrF2 (σ500=2.4×10-2 S/cm). Different types of coordination polyhedrons and their different linking in orthorhombic and tysonite structure explained large differences between conductivities in both structures. Eutectic systems, prepared as directionally solidified composites, enabled to study some orthorhombic fluoride phases (GdF3, SmF3), which cannot be prepared as single crystals. An influence of the orthorhombic-tysonite phase transition on the ionic conductivity was shown.

  20. Magnetic form factors of rare earth ions

    International Nuclear Information System (INIS)

    The magnetic scattering of neutrons by atoms has been investigated by exploiting its similarity to the radiation problem in spectroscopy. Expressions for the magnetic scattering amplitude were developed for cases in whcih an atom in the l/sup n/ electronic configuration is described either by a relativistic or nonrelativistic Hamiltonian. For each of these cases, it has been shown that the magnetic scattering amplitude can be expressed in terms of relativistic or nonrelativistic matrix elements of magnetic and electric multipole operators. For a nonrelativistic atom, the calculation of these matrix elements has been separated into evaluating radial matrix elements and matrix elements of Racah tensors W/(sup 0,k)k/ and W/(sup 1,k')k/. For a relativistic atom the effective operator approach has been used to define effective multipole operators so that a relativistic result is obtained by taking matrix elements of these effective operators between nonrelativistic states of the atom. The calculation of matrix elements of these effective operators has been reduced to evaluating relativistic radial integrals and matrix elements of the Racah tensors taken between nonrelativistic states of the atom. It is shown tha for the case of elastic scattering by either a relativistic or nonrelativistic atom in single Russel-Saunders state, the magnetic scattering amplitude can be written in the conventional form p(vector q)vector q/sub m/.vector sigma. General expressions for p(vector q) as well as elastic magnetic form factorshave been obtained. The formalism has been illustrated throughout by applying it to the case of scattering by rare earth ions

  1. Rare earth elements in Hamersley BIF minerals

    Science.gov (United States)

    Alibert, Chantal

    2016-07-01

    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.

  2. METHOD OF SEPARATING TETRAVALENT PLUTONIUM VALUES FROM CERIUM SUB-GROUP RARE EARTH VALUES

    Science.gov (United States)

    Duffield, R.B.; Stoughton, R.W.

    1959-02-01

    A method is presented for separating plutonium from the cerium sub-group of rare earths when both are present in an aqueous solution. The method consists in adding an excess of alkali metal carbonate to the solution, which causes the formation of a soluble plutonium carbonate precipitate and at the same time forms an insoluble cerium-group rare earth carbonate. The pH value must be adjusted to bctween 5.5 and 7.5, and prior to the precipitation step the plutonium must be reduced to the tetravalent state since only tetravalent plutonium will form the soluble carbonate complex.

  3. Numerical Simulation on the Device of Rare Earth Oxide Preparation by Rare Earth Chloride Spray Pyrolysis

    Directory of Open Access Journals (Sweden)

    Yan Liu

    2015-01-01

    Full Text Available Based on the industrial applications of jet pyrolysis technology and it being used for the production of rare earth oxides, the paper hopes to find out an efficient, economic, and environmental friendly new technology which is suitable for production of rare earth oxides. In this paper, a chloride pyrolysis water model is designed, and standard κ-ε turbulence model and VOF model were coupled to simulate the three-dimensional steady gas-liquid flow in jet reactor. The valuable parameter we got provides strong basis for the experimental equipment manufacturing in thermal state and determining test program. Conclusions show that when the drainage tube diameter is 3 mm, it can guarantee that two-phase distribution of the gas-liquid is more uniform and easy for gas-liquid mixing in the tail region of the Venturi tube. If the fluid near the middle of the duct in front of the Venturi starts to reach equilibrium as constant speed flowing, it proves that elongated pipe is conducive to obtain a stable flow of air required by experiments. In the adjustable pipeline location of the Venturi tube, fluid can form a closed loop and generate reflux in the export where atomization and gas-liquid mixing have good effects.

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

    Institute of Scientific and Technical Information of China (English)

    Qian Jiuhong; Li Guoping

    2004-01-01

    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.

  5. Bioleaching of rare earth elements from monazite sand.

    Science.gov (United States)

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

    2016-02-01

    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. PMID:26332985

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

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ 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.

  7. Electrowinning of high purity individual rare earth metals - a review

    International Nuclear Information System (INIS)

    Rare earth metals are finding applications in various fields. The demand for purer individual metals is increasing. The two important methods of preparation of the pure metals are Metallothermic Reduction and Electrowinning. In Electrowinning, the rare earth fluoride, chloride or oxide is elctrolysed using direct current. Fused salt electrolysis is the commonly used method. The important developments in the area of electrometallurgy is summarised in this paper. In general, the paper deals with the important findings and developments in the process development of electrowinning of rare earth elements. (author) 49 refs., 1 fig., 1 tab

  8. Advances on Rare Earth Application in Pollution Ecology

    Institute of Scientific and Technical Information of China (English)

    Huang Xiaohua; Zhou Qing; Zhang Guangsheng

    2005-01-01

    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.

  9. Rare earth doped solid state laser gain medium

    International Nuclear Information System (INIS)

    Among the rare earths, Nd has been one of the most popular laser active ions, however in recent times there is lot of interest on other ions like Yb as it has low quantum defect. This talk shall focus mainly on the growth of rare earth doped YVO4 single crystals by optical floating zone technique. Single crystals of YVO4 doped with rare earth is widely used for compact diode pumped solid state lasers as it offers several advantages like high slope efficiency, low laser threshold, wide pumping bandwidth and linearly polarized emission

  10. Influence of Rare Earth on Carbide in Weld Metal

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yuan-Bin; REN Deng-Yi

    2003-01-01

    The influence of rare earths (RE) on carbides in high carbon steel weld metal was studied by transmission electron microscope (TEM) and energy dispersive X-ray microanalysis (EDX). It is found that rare earth markedly affects the quantity, morphology and distribution of carbides. The precipitating mechanism of carbides was proposed in which rare earth compounds with high surface energy serve as the nucleation sites for carbides in superheated liquid metal and the induced carbides are precipitated extensively and distributed evenly. The preferential precipitation of carbides decreases the carbon content in matrix, which is transformed into low carbon lath martensite after welds are chilled to room temperature.

  11. Preparation and properties of 3-nitro phthalates of rare earth elements and some transition elements

    International Nuclear Information System (INIS)

    All investigated rare earths nitro phthalates have been prepared by chemical reactions of 3-nitro phthalic acid and respective hydroxides. The products' purity and their structure have been identified by means of IR spectra. The crystal structure of interesting compounds have also been investigated. The powder Debye's-Scherrer's roentgenographic method has been used. Dehydratation process for 3-nitro phthalates of rare earths and some transition elements has been studied during their heating up to 523 K. Solubilities in water and conductivities of aqueous solutions for all investigated compounds have been determined in 293 K. Physico-chemical properties of 3-nitro phthalates of rare earths and transition elements have been compared with respective values for phthalates, well known from the literature. The influence of nitro group presence in the molecule has been discussed on that base. 105 refs, 26 figs, 30 tabs

  12. Extraction and stripping of rare earths using mixtures of acidic phosphorusbased reagents

    Institute of Scientific and Technical Information of China (English)

    WANG Xianglan; LI Wei; LI Deqian

    2011-01-01

    Studies were carried out on the extraction characters of trivalent rare earths from chloride solutions using organophosphorus acids 2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester (HEHEHP) combined with [di-(2-ethylhexyl)-phosphoric acid (HDEHP), isopropylphosphonic acid l-hexyl-4-ethyloctyl ester (HHEOIPP), bis(2,4,4-trimethylpentyl)-phosphinic acid (Cyanex 272), bis(2,4,4-trimethypen-tyl)-monothiophosphinic acid (Cyanex 302) or bis(2,4,4-trimethypentyl)-dithiophosphinic acid (Cyanex 301)] as extractants. The effect of the equilibrium aqueous acidity on the extraction was studied. According to the corresponding separation factors for adjacent pairs of rare earths,it could be concluded that HEHEHP and Cyanex 272 could be employed for the separation of Tm(Ⅲ), Yb(Ⅲ), Lu(Ⅲ) from the other rare earths. Taking Yb(Ⅲ) as an example, based on the different stripping acid, the potential of the stripping was estimated.

  13. Extraction of yttrium group rare earth and yttrium(3) nitrates with tri-n-butylphosphates from multicomponent solutions

    International Nuclear Information System (INIS)

    Extraction of yttrium group rare earth metals(3) nitrate and yttrium(3) nitrate from multicomponent solutions of tri-n-butylphosphate at T = 298.15 K and pH 2 was considered. Physicochemical and mathematical models describing distribution of lanthanides (samarium-lutetium) and yttrium(3) in the multicomponent solutions, depending on total concentration of rare earth metal ions in aqueous solution and composition of concentrates, are presented

  14. Compact Rare Earth Emitter Hollow Cathode

    Science.gov (United States)

    Watkins, Ronald; Goebel, Dan; Hofer, Richard

    2010-01-01

    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

  15. Trace recovery of uranium and rare earth contained in phosphates by liquid-liquid extraction in sulfuric attack liquor

    International Nuclear Information System (INIS)

    Uranium and rare earths can be recovered in sedimentary phosphates during the wet processing of the ore by sulfuric acid giving raw phosphoric acid at 30 per cent of P2O5. Practically all the uranium contained and only part of rare earths are put into solution in this treatment. Separation of these elements in the phosphoric solution is obtained by liquid-liquid extraction with alkylphosphoric acids and especially with their mono and di esters. Partition isotherms are determined and counter-current tests are effected. Uranium and rare earths reextraction from these solvents can be simultaneous or separate with aqueous solutions alkaline or containing HF or by antisynergism. Pros and cons of each reextraction process are discussed. In conclusion HDEHP or OPPA are recommended because of availability, stability and hydrodynamic, OPPA less selective with rare earths allows the recovery with uranium of ceric earths, yttrium and yttric earths

  16. Science and technology of the rare earth elements

    International Nuclear Information System (INIS)

    The present work studies the chemical physics properties, the different methods of analysis (neutron activation, emission spectrometry, chromatography), and the techniques of separation of rare earth (electrodeposition, thermic decomposition, salts distillation and ions exchange)

  17. Magneto-Optical Experiments on Rare Earth Garnet Films.

    Science.gov (United States)

    Tanner, B. K.

    1980-01-01

    Describes experiments in which inexpensive or standard laboratory equipment is used to measure several macroscopic magnetic properties of thin rare earth garnet films used in the manufacture of magnetic bubble devices. (Author/CS)

  18. Monolithic Rare Earth Doped PTR Glass Laser Project

    Data.gov (United States)

    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...

  19. Dendriform pulmonary ossification in patient with rare earth pneumoconiosis

    OpenAIRE

    Yoon, H.; Moon, H.; Park, S.; J. Song; Lim, Y.; Kohyama, N

    2005-01-01

    The case history is presented of a patient with pathologically proven dendriform pulmonary ossification and rare earth pneumoconiosis confirmed by analytical transmission electron microscopy. This is thought to be the first report of this association.

  20. Local magnetic susceptibility in rare-earth compounds

    CERN Document Server

    Shiozawa, H; Obu, K

    2003-01-01

    The element specific magnetic susceptibilities of some rare-earth compounds are estimated by measuring magnetic circular dichroism at rare-earth M sub 4 sub , sub 5 absorption edges. The temperature dependences of the rare-earth 4f local magnetic susceptibilities in dense Kondo materials, CeNi, CeSn sub 3 and CeRu sub 4 Sb sub 1 sub 2 , are remarkably different from those of the bulk magnetic susceptibilities measured by a conventional magnetometer, although the 4f electron is regarded to mainly hold the magnetic moment in these compounds. In contrast, the rare-earth 4f local magnetic susceptibility of ferromagnetic NdFe sub 4 P sub 1 sub 2 shows almost as similar behavior as the bulk one.

  1. ORIGIN OF COBALT ANISOTROPY IN RARE EARTH-COBALT INTERMETALLICS

    OpenAIRE

    Ballou, Rafik; Lemaire, R.

    1988-01-01

    The strong cobalt anisotropies in rare earth-cobalt intermetallics are shown to arise from orbitally selective 3d band energy dispersion due to either chain like or layered like cobalt staking rather than from usual crystal field effect.

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

    Science.gov (United States)

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

    2016-01-01

    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.

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

    Science.gov (United States)

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

    2014-01-01

    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. A study of rare earth doped silicate and phosphate glasses

    OpenAIRE

    Bowron, Daniel Timothy

    1994-01-01

    The complementary techniques of X-ray diffraction and EXAFS have been applied to silicate and phosphate glass systems containing varying quantities of rare earth elements. The silicate systems that have been studied are rare earth doped fibre optic preforms of interest to the optoelectronics and telecommunications industry. Techniques were developed to allow spatially resolved diffraction and EXAFS data to be taken from the small ~1mm diameter core region of the preforms. Absorpt...

  5. Theoretical prediction of topological insulator in ternary rare earth chalcogenides

    OpenAIRE

    Yan, Binghai; Zhang, Hai-Jun; Liu, Chao-Xing; Qi, Xiao-Liang; Frauenheim, Thomas; Zhang, Shou-Cheng

    2010-01-01

    A new class of three-dimensional topological insulator, ternary rare earth chalcogenides, is theoretically investigated with ab initio calculations. Based on both bulk band structure analysis and the direct calculation of topological surface states, we demonstrate that LaBiTe3 is a topological insulator. La can be substituted by other rare earth elements, which provide candidates for novel topological states such as quantum anomalous Hall insulator, axionic insulator and topological Kondo ins...

  6. Social and Environmental Impact of the Rare Earth Industries

    OpenAIRE

    Saleem H. Ali

    2014-01-01

    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 (LA...

  7. Rare Earth Doped Polymer Waveguide Materials and Devices

    Institute of Scientific and Technical Information of China (English)

    Edwin; Y.B.Pun

    2007-01-01

    1 Results Rare earth doped waveguide amplifiers and devices have been demonstrated in silica, crystal and other glass hosts. These rare earth doped optical waveguide devices are based on inorganic materials. Many processing steps are required and can lead to long fabrication time and low yield.Polymer materials offer many distinct properties compared to inorganic materials, such as ease of fabrication, low production costs, simple processing steps, and compatibility with micro-fabrication technologies. ...

  8. Chromates (3) and chromates (5) of rare earths

    International Nuclear Information System (INIS)

    Data on preparation methods, structure and properties of chromates (3, 5) and mixed chromates (3) of rare earths, scandium and yttrium are generalized. Phase diagrams of systems Ln2O3-Cr2O3 (Ln - rare earths, Sc, Y), chemical and thermodynamic properties of chromates (3, 5), their crystal structure and character of thermal decomposition are considered. Application fields of the compounds mentioned are suggested

  9. Rare Earth-Activated Silica-Based Nanocomposites

    Directory of Open Access Journals (Sweden)

    C. Armellini

    2007-01-01

    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.

  10. Electronic structure and properties of rare earth and actinide intermetallics

    International Nuclear Information System (INIS)

    There are 188 contributions, experimental and theoretical, a few on rare earth and actinide elements but mostly on rare earth and actinide intermetallic compounds and alloys. The properties dealt with include 1) crystal structure, 2) magnetic properties and magnetic structure, 3) magnetic phase transformations and valence fluctuations, 4) electrical properties and superconductivity and their temperature, pressure and magnetic field dependence. A few papers deal with crystal growth and novel measuring methods. (G.Q.)

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

    CERN Document Server

    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

    1999-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    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.

  13. On possibility of flotation separation of rare earth ions

    International Nuclear Information System (INIS)

    The possibility of flotation separation of rare earth ions is shown by their crushed precipitating with fatty-acid collectors and subsequent flotation of the formed precipitations. The object of investigation are binary chloride mixtures of lanthanum and yttrium, lanthanum and europium, europium and gadolinium. The pH values of solutions equal to 3.0-7.5; each metal concentration in solutions - 100 mg/l. 0.07 M potassium caprate water solution has been used as rare earth ion precipitant. It has been found out that effective rare earth ion flotation separation is possible only within the strictly determined range of pH values of their solutions, which lies between 4 and 5. It has been shown that rare earth ion separation increase can be achieved by the multiple repetition of the separation process. The duration of rare earth salts solutions mixing after addition to them the collector does not considerably influence the effectiveness of rare earth ion flotation separation

  14. Rare earth industries; Moving Malaysia's Green Economy Forward

    International Nuclear Information System (INIS)

    There is a famous saying, Where there is risk, there is opportunity. Rare earths present both health and environmental risks as well as potential economic opportunities. However, the risks are manageable thanks to improved technologies and a better understanding of the implications on health and the environment. This explains why there is a rush by many countries to reopen old mines and increase investment in the production of rare earths concentrate and their high value downstream products. Why is there such a scramble to risk money on rare earths? What have ignited global demand? Where are the opportunities? How are the risks associated with rare earths managed? Can Malaysia benefit from this new growth industry? What should be our strategies? This report, produced by the joint Working Group of the Academy of Sciences Malaysia (ASM) and the Majlis Professor Negara (MPN), discusses the science of rare earths and their business prospects; and proposes some strategic directions for Malaysia. The analysis is based on information culled from various secondary sources as well as the groups engagement with experts from the Rare Earths Society of China. (author)

  15. Adjacent stage impurity ratio in rare earth countercurrent extraction process

    Institute of Scientific and Technical Information of China (English)

    CHENG Fuxiang; WU Sheng; LIAO Chunsheng; YAN Chunhua

    2013-01-01

    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.

  16. Application of the phase transfer catalyst in rare earth solvent extraction

    International Nuclear Information System (INIS)

    In order to overcome the stripping difficulty and reduce the equilibrium time in heavy rare earth separation with acidic organophosphorous extractants, the phase transfer catalysis (PTC) technique was introduced to the solvent extraction process. It was especially applied to the stripping section, which was called phase transfer catalysis stripping (PTCS) process. In the PTCS process, an acidic phosphorous extractant was mixed with another extractant which could transfer hydrogen ion from aqueous phase to organic phase and almost did not extract rare earth ions, so that the stripping efficiency could be improved and the stripping extraction equilibrium be accelerated. The reaction mechanism of the PTCS and the requisite properties for a feasible PTCS catalyst in the rare earth extraction were studied. We selected D2EHPA as the extractant, Alamine 336 as the PTCS catalyst and mixed rare earth chlorides as the feed to test the PTCS phenomenon. Based on the experimental data, the possibility of applying the PTCS technique in rare earth solvent extraction was discussed. (authors)

  17. Precipitation of the rare earth double sodium and rare earths from the sulfuric liquor and the conversion into rare earth hydroxides through meta ethic reaction

    International Nuclear Information System (INIS)

    This work presents the purification study of the rare earths through precipitation of rare earth and sodium (Na TR (SO4)2. x H2O)) double sulfate and his conversion to rare earths hydroxide TR(OH)3 by meta ethic reaction through the addition of sodium hydroxide solution to the solid double sulfate. The study used the sulfuric liquor as rare earth sample, generated in the chemical processing of the monazite with sulfuric acid by the Industrias Nucleares do Brasil - INB, Brazil, after the thorium and uranium extraction. The work investigated the influence of the main variables involved in the precipitation of Na TR(SO4)2.xH2O and in the conversion for the TR(OH)3, as follows: type and excess of the precipitation agent, temperature and time reaction. The obtained solid composites were characterized by X-ray diffraction, infrared and chemical analysis. The double sulfate diffractogram indicated the Na TR(SO4)2 mono-hydrated. The characterization of the metatese products has shown that, for obtaining the complete conversion of NaTR(SO4)2.H2O into TR(OH)3, the reaction must be hot processed (∼70 deg C) and with small excess of Na OH (≤ 5 percent). (author)

  18. Green inhibitors. Rare Earth based systems

    International Nuclear Information System (INIS)

    Lanthanum, Cerium and Samarium chlorides have been investigated as uniform and pitting corrosion inhibitors of AISI 434 and AISI 304 stainless steels and AA 5083 Al-Mg alloy in 3.5% Na Cl aerated aqueous solutions. Their inhibitor power was evaluated by using electrochemical techniques such as Linear and Cyclic Polarisation. In each case, the highest protection degree was found in the solution dropped with 500 ppm of CeCl3. Similar results were obtained for additions of 500 ppm of LaCl3. Scanning Electron Microscopy and Energy Dispersive Spectroscopy allowed us to confirm the cathodic nature of the inhibition process. (Author) 27 refs

  19. Adsorptive separation of rare earths by using chelating chitosan

    International Nuclear Information System (INIS)

    Two kinds of chelating chitosan were prepared by chemically modifying chitosan with functional groups of EDTA or DTPA, abbreviated as EDTA- and DTPA-chitosan hereafter, respectively, to investigate the adsorption behaviour for rare earths the mutual separation of which is the most difficult among metal ions on these chelating chitosan from dilute hydrochloric or sulfuric acid solution. The plots of the distribution ratio of a series of rare earths against equilibrium pH lay on different straight lines with slope of 3 corresponding to each earth for both of two chelating chitosan, suggesting that 3 hydrogen ions are released for the adsorption of unit ion of each rare earth by chelate formation with the functional group of EDTA or DTPA and that mutual adsorptive separation between adjacent rare earth is possible with these chelating chitosan. Apparent equilibrium constants of the adsorption were evaluated from the intercepts of these straight lines with the ordinate for each rare earth and for both chelating chitosan. It was found that the equilibrium constants of adsorption on EDTA- or DTPA-chitosan are quite analogous to those of chelate formation with EDTA or DTPA themselves, suggesting that chelating characteristics of these complexones is still maintained after their immobilization on polymer matrices of chitosan. (author)

  20. Production and identification of rare-earth doped lithium triborate

    Energy Technology Data Exchange (ETDEWEB)

    Ardicoglu, Burcu [Mining Engineering Department, Middle East Technical University, 06531 Ankara (Turkey); Ozbayoglu, Guelhan [Mining Engineering Department, Middle East Technical University, 06531 Ankara (Turkey)]. E-mail: gulhano@metu.edu.tr; Ozdemir, Zeynep [Mining Engineering Department, Middle East Technical University, 06531 Ankara (Turkey); Yilmaz, Aysen [Chemistry Department, Middle East Technical University, 06531 Ankara (Turkey)

    2006-07-20

    Research in the field of non-linear optical (NLO) devices lead to an increasing interest in new borate compounds, capable of expanding the frequency range provided by common laser sources. Lithium triborate (LBO) is a newly developed ideal non-linear optical crystal used in laser weapon, welder, radar, tracker, surgery, communication, etc. In this study, synthesis and identification of rare-earth doped lithium triborate was carried out. Borates containing rare-earth elements are of great interest since they are found to be superior in non-linear optical applications. Lithium triborate was produced from the solid-state reaction. Lithium triborate was then doped with some rare-earth elements (Gd, La, Y, etc.) in several different concentrations. In this study, LBO samples doped with Gd are presented. Characterization of the new products was done by X-ray diffraction (XRD) and infrared (IR) analysis. Differential thermal analysis (DTA) was used for examination of the thermal properties of the compounds, morphology of new compounds was observed by scanning electron microscopy (SEM). The compounds are then subjected to thermoluminescence (TL) studies. From the XRD studies, no change related to addition of the rare-earth elements was observed. IR analysis showed that there is no change related to B-O link with the addition of rare-earth elements. DTA studies showed that the melting point of LBO decreases with the addition of rare-earth elements. In the SEM images, particles of rare-earth elements and lithium triborate were observed clearly.

  1. The recovery of rare earth elements (REE) from beach sands

    International Nuclear Information System (INIS)

    This preliminary study describes a metallurgical process that will extract, recover and produce REE oxides from beach sands obtained from Ombo, San Vicente, northern Palawan. The beach sands contain REE minerals of allanite and small amounts of monazite. Allanite is a sorosilicate mineral containing rare earths, thorium and uranium. Monazite is the anhydrous phosphate of cerium and the lanthanum group of rare earths with thorium commonly present in replacement for cerium and lanthanum. Collected beach sand were first pan-concentrated in-situ to produce heavy mineral concentrates. Screening using a 32 mesh (0.500 mm) sieve was done at the Nuclear Materials Research Laboratory to remove oversize sand particles. The -32 mesh fraction was treated with bromoform (sp. gr. 2.89) to separate the heavy minerals from siliceous gangue. Grinding to -325 mesh size (0.044mm) followed to liberate the minerals prior to leaching. Two acids leachants were used - concentrated HCl for the first trial and a mixture of concentrated HCl and HNO3 (10:1 volume ratio) for the second trial. Both leaching trials were carried out at 180oC for 7 hours or until dry. The resulting leached residues were re-dissolved in concentrated HCl and filtered. IonquestR 801, an organophosphorous extractant, was added to the filtrate to separate the radioactive thorium from REE. Sodium hydroxide was added to the aqueous phase to precipitate the REE. After filtering the precipitate, it was dissolved in HCl. The acid solution was repeatedly extracted three (3) times with IonquestR 801 to remove iron and other contaminants. Ammonium hydroxide was added to the final solution to precipitate the REE, which was then dried in the oven. The precipitate was calcined/roasted in the furnace at two different temperatures for different periods of time to burn off the organic matter and to form oxides. Results of the XRD analysis showed peaks of the calcined precipitate matching with the peaks of lanthanum oxide standard

  2. Rare earth elements in synthetic zircon. 1. synthesis, and rare earth element and phosphorus doping.

    Energy Technology Data Exchange (ETDEWEB)

    Hanchar, J. M.; Finch, R. J.; Hoskin, W. O.; Watson, E. B.; Cherniak, D. J.; Mariano, A. N.; Chemical Engineering; George Washington Univ.; Univ. of Canterbury; Australian National Univ.; Rensselaer Polytechnic Inst.

    2001-05-01

    Sedimentary mineral assemblages commonly contain detrital zircon crystals as part of the heavy-mineral fraction. Age spectra determined by U-Pb isotopic analysis of single zircon crystals within a sample may directly image the age composition--but not the chemical composition--of the source region. Rare earth element (REE) abundances have been measured for zircons from a range of common crustal igneous rock types from different tectonic environments, as well as kimberlite, carbonatite, and high-grade metamorphic rocks, to assess the potential of using zircon REE characteristics to infer the rock types present in sediment source regions. Except for zircon with probable mantle affinities, zircon REE abundances and normalized patterns show little intersample and intrasample variation. To evaluate the actual variation in detrital zircon REE composition in a true sediment of known mixed provenance, zircons from a sandstone sample from the Statfjord Formation (North Sea) were analyzed. Despite a provenance including high-grade metasediment and granitoids and a range in zircon age of 2.82 b.y., the zircon REEs exhibit a narrow abundance range with no systematic differences in pattern shape. These evidences show zircon REE patterns and abundances are generally not useful as indicators of provenance.

  3. TUNGSTEN ELECTRODES CONTAINING THREE TYPES OF RARE EARTH OXIDES

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Three types of tungsten electrodes containing three rare earth oxides, namely Y2O3, La2O3,and CeO2 and one with Y2O3 and CeO2 were prepared, in which the total contents of rare earth oxides are 2.2 % in mass, and the characteristics of these electrode materials were studied. By TIG welding, the welding characteristics including arc starting, arc static properties and electrode consumption of these electrodes were also analyzed. The results suggest that the electrodes added three rare earth oxides are more favorable for processing than that added two rare earth oxides. All the electrodes activated with two or more rare earth oxides are more superior to W-ThO2 in operating, and the electrode combined with Y2O3 and CeO2 shows the best properties when it is used at a heavy current for a long time. The analyses of the results of electrode consumption indicates that the rim forming during arcing is one of the important reasons for electrode's heavy erosion,and the increased Y2O3 content in electrodes is beneficial to retard the formation of rim, and leads to the improvement of consumption resistance of the electrodes.

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

    Institute of Scientific and Technical Information of China (English)

    马建军; 张淑侠; 朱京涛; 吴贺平

    2004-01-01

    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.

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

    Science.gov (United States)

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

    2016-03-01

    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.

  6. Effect of rare earth oxides on the properties of bio-soluble alkaline earth silicate fibers

    Institute of Scientific and Technical Information of China (English)

    王玺堂; 刘浩; 王周福; 马妍

    2016-01-01

    Using natural mineral wollastonite, talc and quartz sands as raw materials, rare earth oxides (La2O3, Nd2O3 and Y2O3) as additives, the bio-soluble alkaline earth silicate fibers were prepared by melting and blowing process. The viscosity of the molten ma-terials, bio-solubility and crystallization behavior of the fiber were investigated. The results indicated that the fiber drawing tempera-ture range could be broadened since the slope of the temperature-viscosity curve decreased with adding rare earth oxide. The addition of rare earth oxide was beneficial to the increase of crystallization temperature by strengthening the network structure of the fiber. The existence of rare earth oxide in the fibers would reduce the solubility of the fibers, which still belonged to bio-soluble fibers.

  7. Rare Earths and Clean Energy: analyzing China's upper hand

    International Nuclear Information System (INIS)

    An ominous but avoidable resource crunch in the so-called 'rare earth elements' is now threatening the development of a number of key industries from energy to defense to consumer electronics. As key components in the latest generation of technologies, including specialized magnets for windmills and hybrid cars, lasers for range finders and 'smart' munitions, and phosphors for LCD screens, demand for these rare metals is expected to grow rapidly in the years to come. But decades of under-investment in the mining and separation of these elements across the globe has left the industry ill-prepared to meet thi s growing demand. Over the years, only China has recognized the strategic significance of these resources and has succeeded in gaining a near monopoly on production, currently churning out 97% of the world' s rare earth oxides. Faced with problems of its own, and eager to use its resource advantage to master higher levels of value-added production of rare earth-dependent products, China has increasingly limited the rest of the world's access to these raw materials. This only complicates what was already projected to be a problematic resource shortage. This issue demands a higher quality of public debate. Rare earth consuming countries outside of China have only recently become aware of their dependence and started to take stock of the risks. Time is of the essence. Bringing new supplies online to meet growing demand is a long, complicated and risky process but is nevertheless necessary to ensure the development of high tech industries, notably clean energy. Accessible reserves of rare earths do exist outside of China and mitigating the effects of the looming shortage requires opening up these reserves to production. Yet, as the Chinese experience attests, there are substantial risks to the environment associated with mining and separating rare earths. Care must be taken to ensure responsible mining practices across the globe. Longer-term solutions, such as

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

    Science.gov (United States)

    Inoue, Katsutoshi; Alam, Shafiq

    2013-10-01

    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.

  9. Redox reactions in rare earth chloride molten electrolytes

    International Nuclear Information System (INIS)

    Rare earth (REM, Ln) solutions in chloride melts including MCI+LnCl3 mixtures, where M - alkali metals, were investigated by potentiometry, voltammetry, conductometry in wide concentration and temperature intervals. Findings present complete and trusty information on the valent state of rare earths, structure and composition of complex ions affecting essentially on properties of electrolytes. It is demonstrated that the coexistence of rare earth ions with different oxidation level formed as a result of possible redox reactions: 2Ln3+ + Ln ↔3Ln2+, Ln2+ + Ln↔2Ln+ and nM+ + Ln↔nM + Lnn+ appears sharply in thermodynamic and transport properties of molten Ln-LnCl3 and Ln-LnCl3-MCl systems

  10. Investigation and modelling of rare-earth activated waveguide structures

    International Nuclear Information System (INIS)

    In this paper the overview of the recent study on the rare-earth activated waveguides performed in the Optoelectronic Department of IMiO is presented. We reported on the development of rare earth-doped fluorozirconate (ZBLAN) glass fibers that allow a construction of a new family of visible and ultraviolet fiber lasers pumped by upconversion. Especially the performance of holmium devices is presented. The properties of laser planar waveguides obtained by the LPE process and the growth conditions of rare earths doped YAG layers are presented. In this paper we present also the theoretical study of the nonlinear operation of planar waveguide laser, as an example the microdisk Nd:YAG structure is discussed. We derived an approximate formula which relates the small signal gain in the Nd:YAG active medium and the laser characteristics, obtained for whispering-gallery modes and radial modes, to the output power and real parameters of the laser structure (authors)

  11. Method for treating rare earth-transition metal scrap

    Science.gov (United States)

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

    1992-12-29

    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.

  12. Determination of the heavy rare earth radionuclides in melted rock

    International Nuclear Information System (INIS)

    There are some heavy rare earth radionuclides in the melted rocks, such as 160Tb, 168,170Tm, 88,91Y, 174,177Lu, 169Yb, etc.. Because their contents are very low in the melted rocks and the light rare earth fission products are interfered with their determination, it is very complicated to measure them quantitatively. So a new method has been studied in which P507 resin is used to separate and purify the rare earths. Radioactive sources are prepared by the pieces of filter paper for determining chemical yield with X-fluorescence analysis, and radioactive activity is determined with the γ-spectra analysis. It is proved that this method has satisfied the demands of experiments

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

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    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.

  14. Ternary rubidium rare-earth sulphides: synthesis and structure

    International Nuclear Information System (INIS)

    The sulphides Rb Ln S2, where Ln = rare earth metal, could be synthesized by heating a mixture of rubidium carbonate and the selected rare earth sesquioxide in a stream of H2 S. The ternary sulphides form thin mostly coloured plate-like crystals. All compounds crystallize in the α-Na Fe O2 structure type. Relations between the cell parameters as well as the z parameters of the sulphur atoms and the atomic number of the rare earth metals are discussed. The Madelung Part of Lattice Energy [MAPLE] is discussed in detail. All ternary sulphides Rb Ln S2 and Cs Ln S2 are MAPLE-exothermic. (authors). 20 refs., 6 tabs., 5 figs

  15. Spectroscopic properties of rare earths in optical materials

    CERN Document Server

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

    2005-01-01

    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.

  16. Study of determination of rare earth elements by complexometry

    International Nuclear Information System (INIS)

    In this research work, complexometry method has been used for determination of Rare Earth Elements. The reactivity of 5-Bromo-2-(2-pyridylazo)-diethylamino phenol (5-BrPADAP) in the presence of Polyoxyethylene-iso-octano-phenylate (TritomX-100) has been studied and the optimum conditions such as effects of Ph, concentration reagents and interference effect of coexistent ions has been established for the complexometry determination of the individual and mixed of Rare Earth Elements. It was obtained that the absorption peak at 550 nm and its calibration curve to concentration 0.81 p.p.m. was linear. The results was shown that this method is very sensitive (E=1. 16-1. 29x105 L.mol-1.cm-1). It was shown that complexometry method is a worthwhile, simple, rapid and commercial technique having suitable precision and accuracy in design, separation and purification flowsheet from mineral containing Rare Earth Elements

  17. Removal of Phosphorus in Metallurgical Silicon by Rare Earth Elements

    Science.gov (United States)

    Tang, Kai; Løvvik, Ole Martin; Safarian, Jafar; Ma, Xiang; Tangstad, Merete

    2014-09-01

    Removal of phosphorus in metallurgical silicon is one of the crucial steps for the production of solar grade Si feedstock. The possibility of doping rare earth elements for phosphorus removal has in this work been studied both theoretically and experimentally. Thermochemical properties of Ce, Nd, and Pr monophosphides have first been estimated by ab initio thermodynamic simulations based on density functional theory and the direct phonon method. The reliability of the first principles calculations was assessed by coupling with the phase diagram data of the Pr-P system. Equilibrium calculations confirmed the existence of stable rare earth monophosphides in solid silicon. Experimental investigations were then carried out, employing a high temperature resistance furnace. The Ce-doped silicon samples were examined by electron probe micro analyzer and inductively coupled plasma analysis. The efficiency of phosphorus removal by means of rare earth doping was discussed in detail in the paper.

  18. Studies on Three Liquid Phase Extraction (TLPE) system for separation of rare earths

    International Nuclear Information System (INIS)

    Three-liquid-phase extraction (TLPE) is relatively a new separation technique, which takes the advantage of the differences in physicochemical properties of three coexisted phases to achieve multi-phase liquid separation of two or more components in one-step extraction. TLPE system consists of three liquid layers namely an organic solvent phase (organophosphorous type) and two aqueous phases one rich in polymer phase (poly alkylene glycol) and other a salt solution. To study the feasibility of using such system for separation of rare earths, it is important to optimize the preparatory conditions by selective suitable polymer and salt solutions at an appropriate pH to obtain a stable three phase layers to effect the separation. D2EHPA (di-2-ethyl hexyl phosphoric acid) is a well- established extractant in the rare earth industry and has been chosen in the present work to form a TLPE with polymer and salt solution. In the present investigation after preparing the stable three phase, the feasibility of using TLPE has been examined to separate rare earths from a multicomponent solutions. This study has demonstrated the ability of TLPE having D2EHPA as organic phase to separate rare earths from a multicomponent system. Effect of pH, concentration and types of polymer, complexing agent and D2EHPA concentration has been studied. Variation in pH study indicated that 4.0 leads to extraction of rare earths in the polymer phase. PEG 600 was found to be best amongst the polymer investigated. Presence of DTPA as complexing agent in the salt solution having pH >4.0 resulted in enhanced extraction of rare earths in PEG phase

  19. Rare earth aerosol analysis by x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    An analytical method for the determination of four lanthanides in air filter samples is described. The method involves simultaneous quantitative determinations of La, Ce, Pr, and Nd at the microgram level by x-ray fluorescence spectrometry without chemical separation of these rare earths and without serious interferences from the dust matrices on the filters. The method has been used successfully to analyze some air filter samples collected at a rare earth processing refinery in Illinois. A description of the development of the method is given as well as the results obtained by using this method on the air filter samples. The reproducibility of the results was generally +-5%

  20. MBE growth and characterisation of light rare-earth superlattices

    DEFF Research Database (Denmark)

    Ward, R.C.C.; Wells, M.R.; Bryn-Jacobsen, C.; Cowley, R.A.; Goff, J.P.; McMorrow, D.F.; Simpson, J.A.

    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...... trends similar to bulk alloys, with a range of compositions between Ho0.55Pr0.45 and Ho0.35Pr0.65 where the Sm delta-structure is stable, separating more extensive regions of hcp and dhcp solid solutions....

  1. Magnetic Alignment Study of Rare-Earth-Containing Liquid Crystals

    OpenAIRE

    Galyametdinov, Yury; Haase, Wolfgang; Goderis, Bart; Moors, Dries; Driesen, Kris; Van Deun, Rik; Binnemans, Koen

    2007-01-01

    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)...

  2. Rare earth substituted YBa2Cu3Ox

    International Nuclear Information System (INIS)

    We present some selected results obtained using rare earth Mossbauer spectroscopy, on YBa2Cu3Ox partially and/or totally substituted by Yb3+, Er3+ or Dy3+. We report measurements of the single ion crystal field anisotropy and of the size, direction and ordering temperature of the rare earth sublattice magnetic moments. We use dilute 170Yb3+ ions to probe both the Cu(2) derived internal (molecular) fields and the fluctuation frequencies of the short range correlated Cu(2) moments. We monitor these frequencies as the carrier level is changed up towards the threshold needed to stabilise superconductivity

  3. Concentration of light rare earths process by amoniacal precipitation

    International Nuclear Information System (INIS)

    A procedure for the separation and concentration of light rare earths using a mixture of ammonia and water was developed. As a result technical concentrates of rare earths were obtained and the physical separation in the filtration step was improved. The filtration parameters (cake resistance r0 and filtration web resistance R) were obtained for this process being they 5,5.1011 cm/g and 3,4.1013 cm-1 respectively. The proposed technology concentrates (Ce, La and Nd) with purities ranging from: 85-90 %, 85-87 % and 42-65 % respectively in only one precipitation step

  4. THE RARE EARTH PEAK: AN OVERLOOKED r-PROCESS DIAGNOSTIC

    Energy Technology Data Exchange (ETDEWEB)

    Mumpower, Matthew R.; McLaughlin, G. C. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Surman, Rebecca, E-mail: mrmumpow@ncsu.edu, E-mail: gail_mclaughlin@ncsu.edu, E-mail: surmanr@union.edu [Department of Physics and Astronomy, Union College, Schenectady, NY 12308 (United States)

    2012-06-20

    The astrophysical site or sites responsible for the r-process of nucleosynthesis still remains an enigma. Since the rare earth region is formed in the latter stages of the r-process, it provides a unique probe of the astrophysical conditions during which the r-process takes place. We use features of a successful rare earth region in the context of a high-entropy r-process (S {approx}> 100k{sub B} ) and discuss the types of astrophysical conditions that produce abundance patterns that best match meteoritic and observational data. Despite uncertainties in nuclear physics input, this method effectively constrains astrophysical conditions.

  5. The Rare Earth Peak : An Overlooked r-Process Diagnostic

    CERN Document Server

    Mumpower, M; Surman, R

    2012-01-01

    The astrophysical site or sites responsible for the r-process of nucleosynthesis still remains an enigma. Since the rare earth region is formed in the latter stages of the r-process it provides a unique probe of the astrophysical conditions during which the r-process takes place. We use features of a successful rare earth region in the context of a high entropy r-process (S>100k_B) and discuss the types of astrophysical conditions that produce abundance patterns that best match meteoritic and observational data. Despite uncertainties in nuclear physics input, this method effectively constrains astrophysical conditions.

  6. Integrated Automation System for Rare Earth Countercurrent Extraction Process

    Institute of Scientific and Technical Information of China (English)

    柴天佑; 杨辉

    2004-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ 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.

  8. Current extraction and separation of uranium, thorium and rare earths elements from monazite leach solution using organophosphorous extractants

    International Nuclear Information System (INIS)

    A new process based on solvent extraction has been developed for separation of uranium, thorium and rare earths from monazite leach solution using organophosphorous extractants. The Thorium cake coming from monazite source was dissolved in HNO3 medium in presence of trace amount of HF for feed preparation. The separation of U(VI) was carried out by liquid-liquid extraction using tris-2-ethyl hexyl phosphoric acid (TEHP) in dodecane leaving thorium and rare earths elements in the raffinate. The thorium from raffinate was selectively extracted using 1M tri iso amyl phosphate (TiAP) in dodecane in organic phase leaving all rare earths elements in aqueous solution. The uranium and thorium from organic medium was quantitatively stripped using 0.05 M HNO3 counter current mode. Results indicate the quantitative separation of uranium, thorium and rare earths from thorium cake (monazite source) using organophosphorous extractant in counter current mode

  9. Determination of rare-earth elements in geological materials by inductively coupled argon plasma atomic emission spectrometry (ICAP-AES)

    International Nuclear Information System (INIS)

    The determination of 12 rare earth elements viz Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Y and Yb in geological materials, particularly in silicate rocks by ICAP-AES method is descried. Here, the stepwise chemical separation of major elements (Si, Al, Fe, Mg) followed by precipitation of rare earth with fluoride-hydroxide cycles is carried out. This precipitate which is mainly rare earths, is dissolved in HNO3 to get final clear solution. Synthetic aqueous standards are prepared containing rare earths only in the concentration range 0.01 μg/ml to 0.2 μg/ml. JY 1 m Czerny-Turner scanning monochromator is used to measure intensities of rare earth analytical lines selected. The mean relative standard deviation lies between 0.8% to 4.0% for all the elements determined. The mica schist samples are dissolved in HNO3 in combination with diluted HF (1:100) and few drops of perchloric acid. The end sample is taken in 5% nitric acid. Clear solution is obtained which is evaporated to near dry and finally made to a known volume with water. JY -2000 ICP- AES sequential atomic emission spectrometer is used to measure intensities of rare earth elements. Single rare earth element standard solutions are used in the concentration range of 0.l ppm to 10 ppm. (author)

  10. Recovery of lead-208 radiogenic of residues of thorium with rare earth

    International Nuclear Information System (INIS)

    In the middle of the years 1970 in IPEN, considerable work for the purification and conversion of uranium and thorium project, the production of thorium nitrate, a pilot scale from different compounds of Thorium was accomplished; This installation of thorium nitrate produced for national marketing, given the industry of incandescent lighting gas mangles.. The method used by this installation was the purification by solvent extraction with pulsed columns. The thorium was in the organic phase, which was reversed as of thorium nitrate with a high degree of purity. The aqueous phase of this chemical process, containing impurities, some not extracted thorium and virtually all rare earths was precipitated in the form of a hydroxide. This was called RETOTER hydroxide (residue of Thorium and Rare Earth). This residue containing thorium, rare earth and some impurities such as lead-208 product of the decay of thorium-232 were stored in the shed of safeguarding IPEN for further recovery of thorium and rare earth. In this work was studied the recovery of lead-208, nuclear material of interest, separating it by the technique of cementation , where it adds zinc metallic to an acid solution of RETOTER, holding up the lead on the surface of the metallic zinc. (author)

  11. Rare earth intermetallic compounds produced by a reduction-diffusion process

    International Nuclear Information System (INIS)

    A reduction-diffusion process is given for producing novel rare earth intermetallic compounds, such as cobalt--rare earth intermetallic compounds, especially compounds useful in preparing permanent magnets. A particulate mixture of rare earth metal halide, cobalt and calcium hydride is heated to effect reduction of the rare earth metal halide and to diffuse the resulting rare earth metal into the cobalt to form the intermetallic compound

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

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ 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".

  13. Rare earths'98. The international rare earths conference, including radio lanthanides in nuclear medicine therapy. Programme and abstracts

    International Nuclear Information System (INIS)

    The rare earth elements and compounds have unique spectroscopic, magnetic and chemical properties. These materials not only provide interesting windows into many aspects of science but are being used in an ever increasing number of strategic applications, particularly in the high growth sectors of world economics. The conference covered various aspects of rare earths elemets and compounds, including photophysics, luminescence and spectroscopy, magnetic materials, minerals and materials characterisation, extraction and co-ordination chemistry, electronic and electrical properties as well as their applications in agriculture, nuclear medicine and environmental studies

  14. Systematic hardness measurements on some rare earth garnet crystals

    Indian Academy of Sciences (India)

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

    2001-10-01

    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.

  15. Thermally stimulated tunneling in rare-earth-doped oxyorthosilicates

    Czech Academy of Sciences Publication Activity Database

    Vedda, A.; Nikl, Martin; Fasoli, M.; Mihóková, Eva; Pejchal, Jan; Dušek, Michal; Ren, G.; Stanek, C.R.; McClellan, K.J.; Byler, D.D.

    2008-01-01

    Roč. 78, č. 19 (2008), 195123/1-195123/8. ISSN 1098-0121 R&D Projects: GA MŠk ME08034; GA AV ČR IAA100100810 Institutional research plan: CEZ:AV0Z10100521 Keywords : scintillator * orthosilicates * rare earth doped * thermoluminescence * tunnelling Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.322, year: 2008

  16. Giant gain in a rare-earth-ion-doped waveguide

    NARCIS (Netherlands)

    Geskus, Dimitri; Aravazhi, Shanmugam; Garcia Blanco, Sonia; Pollnau, Markus

    2011-01-01

    The high dopant concentration, large transition cross-section, and strong light confinement in a large-refractive-index-contrast KGd0.535Yb0.475(WO4)2 channel waveguide on a KY(WO4)2 substrate enable the demonstration of a modal gain of ~1000 dB/cm in a rare-earth-ion-doped material.

  17. Uncovering the end uses of the rare earth elements

    International Nuclear Information System (INIS)

    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

  18. Hydrogen-absorbing characteristics of 15 rare earth elements

    International Nuclear Information System (INIS)

    The amounts of absorbed hydrogen and the rates of hydrogen-absorption reaction were measured for 15 rare earth elements. The cohesive energy and energy fluctuation of metal clusters were also calculated by using the extended-Hueckel method. The characteristics of each rare earth element in the capacity of hydrogen absorption and the reaction rate were discussed by comparing the experimental results with the calculated ones. The major results are as follows. (i) Hydrogen/metal ratios (H/M) of rare-earth metals are nearly constant, ∼3, except for Eu and Yb; (ii) the rate of hydrogen-absorption reaction may be determined by the product of (magnitude of energy fluctuation) and (density of states); (iii) the 15 rare-earth elements would be classified into four groups: Group 1 (Ce, Pr, Nd), Group 2 (Sm, Gd, Tb, Dy, Ho, Er), Group 3 (Tm, Yb, Lu) and Group 4 (Y, La, Eu) and (iv) the rate of hydrogen-absorption reaction is remarkably promoted by pre-heating the metals before the reaction

  19. Crystalline and amorphous rare-earth metallic compounds

    International Nuclear Information System (INIS)

    During the last years the study of magnetic behaviour of rare-earth (or yttrium) compounds with cobalt and iron has growth of interest. This interest of justified by a large area of experimental and theoretical problems coming into being in the study of some rare-earth materials as well as in their technical applications. In the last three years a great number of new rare earth materials were studied and also new models explaining the magnetic behaviour of these systems have been used. In this paper we refer especially to some typical systems in order to analyse the magnetic behaviour of iron and cobalt and also the part played by the magnetic interactions in the values of the cobalt or iron moments. The model used will be generally the molecular field model. In the second chapter we present comparatively the structure of crystalline and amorphous compounds for further correlation with the magnetic properties. In chapter III we analyse the magnetic interactions in some crystalline and amorphous rare-earth alloys. Finally, we exemplify the ways in which we ensure better requried characteristics by the technical utilizations of these materials. These have in view the modifications of the magnetic interactions and are closely related with the analysis made in chapter III

  20. Automation System in Rare Earths Countercurrent Extraction Processes

    Institute of Scientific and Technical Information of China (English)

    贾江涛; 严纯华; 廖春生; 吴声; 王明文; 李标国

    2001-01-01

    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.

  1. Potential synergy: the thorium fuel cycle and rare earths processing

    International Nuclear Information System (INIS)

    The use of thorium in nuclear power programs has been evaluated on a recurring basis. A concern often raised is the lack of 'thorium infrastructure'; however, for at least a part of a potential thorium fuel cycle, this may less of a problem than previously thought. Thorium is frequently encountered in association with rare earth elements and, since the U.S. last systematically evaluated the large-scale use of thorium (the 1970's,) the use of rare earth elements has increased ten-fold to approximately 200,000 metric tons per year. Integration of thorium extraction with rare earth processing has been previously described and top-level estimates have been done on thorium resource availability; however, since ores and mining operations differ markedly, what is needed is process flowsheet analysis to determine whether a specific mining operation can feasibly produce thorium as a by-product. Also, the collocation of thorium with rare earths means that, even if a thorium product stream is not developed, its presence in mining waste streams needs to be addressed and there are previous instances where this has caused issues. This study analyzes several operational mines, estimates the mines' ability to produce a thorium by-product stream, and discusses some waste management implications of recovering thorium. (authors)

  2. Local magnetism in rare-earth metals encapsulated in fullerenes

    NARCIS (Netherlands)

    De Nadai, C; Mirone, A; Dhesi, SS; Bencok, P; Brookes, NB; Marenne, [No Value; Rudolf, P; Tagmatarchis, N; Shinohara, H; Dennis, TJS; Marenne, I.; Nadaï, C. De

    2004-01-01

    Local magnetic properties of rare-earth (RE) atoms encapsulated in fullerenes have been characterized using x-ray magnetic circular dichroism and x-ray absorption spectroscopy (XAS). The orbital and spin contributions of the magnetic moment have been determined through sum rules and theoretical mode

  3. Prospects of using thermoemission properties of rare earth hexaborides

    International Nuclear Information System (INIS)

    Results of earlier conducted experimental study of thermoemission properties of LaB6(100) monocrystal were analyzed. Peculiarities, resulted from marrowness of interelectrode path of thermoemission converter, used in suggested technique, were taken into account. Prospects of using thermoemission properties of rare earth elements in electronics were discussed. 7 refs

  4. Enthalpies of formation and atomization energies of rare earth halides

    International Nuclear Information System (INIS)

    On the basis of experimentally determined atomization energies and formation enthalpies of gaseous rare earth chlorides and theoretical insights of quantum-chemical model ''atom in a molecule'' the analysis of the known literature data on formation enthalpies and atomization energies for lanthanide fluorides, bromides and iodides has been carried out and their values are assessed for unexplored molecules

  5. Complex Electronic Structure of Rare Earth Activators in Scintillators

    International Nuclear Information System (INIS)

    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.

  6. Complex Electronic Structure of Rare Earth Activators in Scintillators

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2015-10-27

    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. Primary Results of New Rare Earth Materials for Hongti Grape

    Institute of Scientific and Technical Information of China (English)

    He Qiong; Gu Jiangyuan; Wang Jiachen

    2004-01-01

    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.

  8. Rare earth point defects in GaN

    Energy Technology Data Exchange (ETDEWEB)

    Sanna, S.

    2007-12-14

    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.)

  9. Study of alpha activity in the region of rare earths

    International Nuclear Information System (INIS)

    The alpha decay half-lives of the Nd144, Cd152 and Er162 isotopes were redetermined using Ilford L4 nuclear emulsions charged with rare earth complexes of natural isotopic composition. The results were compared to results obtained by other authors, and with results calculated by potential barrier penetration theory. (M.C.K.)

  10. Bone uptake of rare earths and transuranic elements

    International Nuclear Information System (INIS)

    In the first part of this paper formation conditions of citric complexes of rare earths and transuranic elements are presented. In the second part, role of binding proteins in plasma is emphasized. Finally biological behaviour of the injected elements is evidenced. A general mechanism for fixation of these elements in bone and liver is proposed

  11. Solubility of fluorides of alkaline earth metals and some rare earths in anhydrous trifluoroacetic acid

    International Nuclear Information System (INIS)

    Solubility of fluorides of alkaline earth and some rare earth metals in anhydrous trifluoroacetic acid is studied. For each type of fluoride solubility depends on the ionic radius of the cation. Solubility of fluorides of alkaline earth metals grows from magnesium to barium. All the fluorides in anhydrous trifluoroacetic acid form solvates. Solvates of strontium and scandium fluorides are shown to decompose at 110 and 150 deg C respectively

  12. Extraction of rare-earth elements from nitric solutions by phosphoryl-containing podands

    International Nuclear Information System (INIS)

    The extraction of microquantities of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y from HNO3 solutions by phosphoryl-containing podands of various structures has been studied.. It has been found that the maximum extraction of rare earth elements is exhibited by reagents containing one ether oxygen atom in the molecule, bound to diphenylphosphoryl or ditolylphosphoryl groups by methylene and o-phenylene fragments. The structure of these reagents is best suited for the polydentate coordination of the ligand and the conditions of a chelate complex formation. The effect of HNO3 concentration in the aqueous phase and that of the nature of an organic diluent on the extraction of rare earth elements and Y are considered. Stoichiometric of the extracted complexes has been determined and the extraction constants calculated

  13. Geochemistry of the rare earths: determination and applications

    International Nuclear Information System (INIS)

    The Earth was formed starting from a chemically homogeneous matter with specific mineralogical and chemical characteristics: nucleus, mantle and crust. About 90 % of the Earth, globally considered, is made up of iron, oxygen, silicon and magnesium. The main part of the iron is concentrated in the nucleus, it is to say, in the central layer. In the crust, the three more abundant elements that conform the external layer of the Earth are oxygen (46%) silicon (28%) and aluminium (8%). The mantle, located between the nucleus and the crust, is made up basically by silicon, magnesium and iron. There exist another elements, for instance, the lanthanides which can give a lot of information about the initial differentiation processes of the Earth. The rare earths or lanthanides are a group of 15 elements included in the atomic numbers 57 to 71 (from lanthanum to lutetium) of the periodic chart; their electronic configurations cause that the 15 elements present chemical characteristics quite similar. An important part of this article is dedicated to the analytical chemistry of the rare earths, presenting both nuclear and nonnuclear analytical methods. This paper is divided in the following sections: Geochemical and chemical properties, Applications to the study of terrestrial processes, and Analytical chemistry. (Author)

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

    Institute of Scientific and Technical Information of China (English)

    HU YUE

    2011-01-01

    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.

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

    DEFF Research Database (Denmark)

    Touborg, P.; Høg, J.

    1974-01-01

    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...

  16. Interplay of iron and rare-earth magnetic order in rare-earth iron pnictide superconductors under magnetic field

    Science.gov (United States)

    Lei-Lei, Yang; Da-Yong, Liu; Dong-Meng, Chen; Liang-Jian, Zou

    2016-02-01

    The magnetic properties of iron pnictide superconductors with magnetic rare-earth ions under strong magnetic field are investigated based on the cluster self-consistent field method. Starting from an effective Heisenberg model, we present the evolution of magnetic structures on magnetic field in R/FeAsO (R = Ce, Pr, Nd, Sm, Gd, and Tb) and R/Fe2As2 (R = Eu) compounds. It is found that spin-flop transition occurs in both rare-earth and iron layers under magnetic field, in good agreement with the experimental results. The interplay between rare-earth and iron spins plays a key role in the magnetic-field-driven magnetic phase transition, which suggests that the rare-earth layers can modulate the magnetic behaviors of iron layers. In addition, the factors that affect the critical magnetic field for spin-flop transition are also discussed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11104274, 11274310, and 11474287) and the Fundamental Research Funds for the Central Universities, China (Grant No. 27R1310020A).

  17. Research on manufacturing aluminum - rare earth alloy with a high content of rare earth (> 20% RE) from total rare earth oxides by thermit reduction

    International Nuclear Information System (INIS)

    In this report, several theoretical principles of thermit reduction method used for metal oxides to obtain metals, ferroalloys and ligatua with technical purity are presented. Manufacture of aluminum-rare earth alloys by thermit reduction is also described in the report. Data that are generalized based on thermo-kinetic calculation of the thermit reduction and selection of technological flow-sheet based on thermal effect will partly clarify research results in investigating typical features of the process and identify measures to reduce metal loss in discharged slags. (author)

  18. Separation of uranium from rare earths in chloride medium using Alamine 336

    International Nuclear Information System (INIS)

    Present work was carried out to optimize a process to separate uranium from rare earths using Alamine-336 (tri-n-octyl amine). This paper describes the process of extraction of uranium from chloride liquor generated after dissolution of impure SDU cake in hydrochloric acid. The solvent used in this study is Alamine-336 which was procured from M/s. Chemical Centre, Mumbai. Dodecane was used as diluent and isodecanol as phase modifier. The extraction and stripping experiments were carried out in separating funnels shaken manually at room temperature. The contact time was fixed at five minutes for all the experiments. Following contact, the aqueous phase and the organic phase were separated and the aqueous phase was taken up for analysis. Analysis of uranium and rare earths were done by ICP-AES. Metal extraction by amines depends on the capacity of the metallic ions to form anionic/neutral species in the aqueous media; these species are then extracted by anion exchange mechanism or by adduct formation respectively

  19. The formation of crystals in glasses containing rare earth oxides

    International Nuclear Information System (INIS)

    Korean spent nuclear fuel will reach the capacity of the available temporary storage by 2016. Pyroprocessing and direct disposal seems to be an alternative way to manage and reuse spent nuclear fuel while avoiding the wet reprocessing technology. Pyroprocessing produces several wastes streams, including metals, salts, and rare earths, which must be converted into stabilized form. A suitable form for rare earth immobilization is borosilicate glass. The borosilicate glass form exhibits excellent durability, allows a high waste loading, and is easy to process. In this work, we combined the rare earths waste of composition (in wt%) 39.2Nd2O3–22.7CeO2–11.7La2O3–10.9PrO2–1.3Eu2O3–1.3Gd2O3–8.1Sm2O3–4.8Y2O3 with a baseline glass of composition 60.2SiO2–16.0B2O3–12.6Na2O–3.8Al2O3–5.7CaO–1.7ZrO2. Crystallization in waste glasses occurs as the waste loading increases. It may produce complicate glass processing and affect the product quality. To study crystal formation, we initially made glasses containing 5%, 10% and 15% of La2O3 and then glasses with 5%, 10% and 15% of the complete rare earth mix. Samples were heat-treated for 24 hours at temperatures 800°C to 1150°C in 50°C increments. Quenched samples were analyzed using an optical microscope, scanning electron microscope with energy dispersive spectroscopy, and x-ray diffraction. Stillwellite (LaBSiO5) and oxyapatite (Ca2La8Si6O26) were found in glasses containing La2O3, while oxyapatite (Ca2La8Si6O26 and NaNd9Si6O26) precipitated in glasses with additions of mixed rare earths. The liquidus temperature (TL) of the glasses containing 5%, 10% and 15% La2O3 were 800°C, 959°C and 986°C, respectively; while TL was 825°C, 1059°C and 1267°C for glasses with 5%, 10% and 15% addition of mixed rare earth oxides. The component coefficients TB2O3, TSiO2, TCaO, and TRE2O3 were also evaluated using a recently published study

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

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <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

  1. Efficient separation of transition metals from rare earths by an undiluted phosphonium thiocyanate ionic liquid.

    Science.gov (United States)

    Rout, Alok; Binnemans, Koen

    2016-06-21

    The ionic liquid trihexyl(tetradecyl)phosphonium thiocyanate has been used for the extraction of the transition metal ions Co(ii), Ni(ii), Zn(ii), and the rare-earth ions La(iii), Sm(iii) and Eu(iii) from aqueous solutions containing nitrate or chloride salts. The transition metal ions showed a high affinity for the ionic liquid phase and were efficiently extracted, while the extraction efficiency of the rare-earth ions was low. This difference in extraction behavior enabled separation of the pairs Co(ii)/Sm(iii), Ni(ii)/La(iii) and Zn(ii)/Eu(iii). These separations are relevant for the recycling of rare earths and transition metals from samarium cobalt permanent magnets, nickel metal hydride batteries and lamp phosphors, respectively. The extraction of metal ions from a chloride or nitrate solution with a thiocyanate ionic liquid is an example of "split-anion extraction", where different anions are present in the aqueous and ionic liquid phase. Close to 100% loading was possible for Co(ii) and Zn(ii) up to a concentration of 40 g L(-1) of the transition metal salt in the initial aqueous feed solution, whereas the extraction efficiency for Ni(ii) gradually decreased with increase in the initial feed concentration. Stripping of Co(ii), Zn(ii) and Ni(ii) from the loaded ionic liquid phase was possible by a 15 wt% NH3 solution. The ionic liquid could reused after extraction and stripping. PMID:27243450

  2. Recent developments of rare-earth-free hard-magnetic materials

    Science.gov (United States)

    Li, Da; Pan, DeSheng; Li, ShaoJie; Zhang, ZhiDong

    2016-01-01

    Recent advances in rare-earth-free hard-magnetic materials including magnetic bulk, thin films, nanocomposites and nanostructures are introduced. Since the costs of the rare-earth metals boosts up the price of the high-performance rare-earth permanent magnets, there is a much revived interest in various types of hard-magnetic materials based on rare-earth-free compounds. The 3d transition metals and their alloys with large coercivity and high Curie temperatures (working temperatures) are expected to overcome the disadvantages of rare-earth magnets. Making rare-earth-free magnets with a large energy product to meet tomorrow's energy needs is still a challenge.

  3. Thermodynamic parameters and stabilities of some rare-earth metal ion chelates of alpha-valine

    International Nuclear Information System (INIS)

    Solution equilibrium for some rare-earth metal ions with valine have been studied potentiometrically in aqueous medium at temperature from 25 to 55 deg. C and ionic strength from 0.1 to 1.0 mol dm/sup -3/NaClO/sub 4/. The thermodynamic parameters delta H, delta S, delta G for the formation process were evaluated in terms of temperature, ionic strength and nature of metal ion present. The stability of the complexes was found to: La(III)< Nd(III)< Gd(III)< Eu(III)Yb(III)< Lu(III). (author)

  4. Electrodeposition of luminescent composite metal coatings containing rare-earth phosphor particles

    OpenAIRE

    Ganapathi, Murugan; Eliseeva, Svetlana V.; Brooks, Neil; Soccol, Dimitri; Fransaer, Jan; Binnemans, Koen

    2012-01-01

    Mixtures of acetamide and dimethylsulfone (DMSO2) with dissolved anhydrous transition metal chlorides are introduced as new non-aqueous electrolytes for the preparation of composite metal coatings with embedded hydrophilic particles via an electrolytic co-deposition process. Red-emitting (Eu2O3 and Y2O3:Eu3+), yellow-emitting (Y3Al5O12:Ce3+), green-emitting (Gd2O2S:Tb3+) and blue-emitting (BaMg2Al16O27:Eu2+) rare-earth phosphor particles and yttrium oxide particles have been embedded into thi...

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

    Directory of Open Access Journals (Sweden)

    Yliruokanen, I.

    1995-12-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

    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.

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

    DEFF Research Database (Denmark)

    Williams, R. W.; Mackintosh, Allan

    1968-01-01

    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...

  8. Microstructural characterisation of epitaxial rare earth metal based films

    International Nuclear Information System (INIS)

    Epitaxial rare earth films and superlattices grown by molecular beam epitaxy, MBE, can be designed to investigate theoretical predictions of the magnetic and electronic properties of the metals. These investigations ideally require smooth epitaxial layers with atomically flat interfaces and therefore the microstructure of selected epitaxial rare earth systems has been characterised by a combination of techniques. These systems were grown on a (110) niobium parallel (112-bar0) sapphire substrate. Because the crystallographic quality of the subsequent layers is influenced by the quality of the substrate, the niobium-sapphire interface was studied with transmission electron microscopy, TEM, and high resolution electron microscopy, HREM, to identify uniquely the misfit dislocation network. Conventional TEM specimen preparation techniques were inappropriate for the preparation of metallic foils, and so appropriate specimen preparation techniques were developed. HREM was used to characterise the strain relief mechanisms within a partially relaxed holmium/yttrium superlattice

  9. Investigation into thermal decomposition of rare earth metaantimonates

    International Nuclear Information System (INIS)

    Thermal decomposition of rare earth metaantimonates of Ln(SbO3)3 has been studied by the chemical, X-ray fluorescent, and X-ray phase analyses within the temperature range of 900-1400 deg C. The formation of intermediate compounds has been established, namely, rare earth antimonates Lnsub(2)Sbsub(3)Osub(10.5)(1) and LnSbO4(2), and of the final LnSbO7(3), where Ln=La, lanthanides in the series of Pr-Lu. The crystal structure of these compounds has been determined by the analytical method: 1 compound has a hexagonal lattice, 2 rhombic lattice, and 3 compound crystallizes in the structure of the fluoride type

  10. Coupled channels optical model potential for rare earth nuclei

    International Nuclear Information System (INIS)

    The global spherical optical model by Koning and Delaroche is generalized to enable its use in coupled-channel calculations on well deformed nuclei in the rare-earth region. The generalization consists in adding the coupling of the ground state rotational band, deforming the potential by introducing appropriate quadrupole and hexadecupole deformations and correcting the optical model potential radius to preserve the volume integral of the spherical optical potential. We choose isotopes of three rare-earth elements (W, Ho, Gd), which are known to be nearly perfect rotors, to perform a consistency test of our conjecture on integrated cross sections as well as on angular distributions for elastic and inelastic neutron scattering. The only additional input are experimentally determined deformations, which we employ without any adjustments. The results are clearly superior compared to the spherical optical model calculations with dramatic improvement at low incident energies. (author)

  11. Electrons and Spin Waves in Heavy Rare Earth Metals

    DEFF Research Database (Denmark)

    Mackintosh, A. R.

    1972-01-01

    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...... understanding on a more quantitative basis. The experimental evidence on the electronic structure of the rare earths is still rather meager but, so far as it goes, is in accord with the detailed description provided by band structure calculations. On the other hand, the experimental study of the magnon...... dispersion relations by inelastic neutron scattering has provided a wealth of information about the interactions between the local moments, associated with the incompletely filled 4f subshell, and the rest of the crystal. The main emphasis in these notes will be on the interrelation between the electronic...

  12. Radioluminescence of rare-earth doped aluminum oxide

    International Nuclear Information System (INIS)

    Al2O3:C is one of the most used radioluminescence materials for fiberoptic dosimetry due mainly to its high efficiency. However, this compound presents the drawback of emitting in the spectral region, where the spurious radioluminescence of fibers is also important. In this work, sintered samples of Al2O3:C doped with Tb, Sm, Ce and Tm have been prepared by combustion synthesis and their radioluminescence responses have been evaluated. The influence of the different activators on the radioluminescence spectra has been investigated. - Highlights: ► Rare earth doped Al2O3 as radiation detector for fiberoptic dosimetry evaluated. ► Samples fabricated by low cost combustion synthesis (CS) route. ► Positive: CS successes to incorporate rare earth cations into Al2O3 host. ► Positive: Constant response on dose, no afterglow and red emission. ► Negative: low efficiency. CS procedure deserves improvement.

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

    Energy Technology Data Exchange (ETDEWEB)

    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: tomas.calderon@uam.es; Jaque, D.; Garcia Sole, J. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Cantoblanco, Madrid (Spain)

    2008-05-15

    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.

  14. Preparation and Characterization of Rare Earth Doped Fluoride Nanoparticles

    OpenAIRE

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

    2010-01-01

    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...

  15. New rare earth-based magnetocaloric materials for magnetic refrigeration

    OpenAIRE

    Mayer, Charlotte

    2011-01-01

    The studies presented in this manuscript deal with the synthesis and characterization of new rare-earth based magnetocaloric materials for magnetic refrigeration applications. The first chapter is an introduction to the concepts of magnetocaloric effect and magnetic refrigeration and establishes a review of the magnetocaloric materials existing today. Two research axes were explored in order to obtain materials with a high refrigeration capacity (RC) and to identify strategies for improving t...

  16. Disposal of Rare Earth NORM Residues in Jiangsu Province, China

    International Nuclear Information System (INIS)

    The present situation of NORM residues arising from rare earths extraction and separation in Jiangsu Province has been investigated comprehensively. The management of these residues is discussed and analysed with respect to the separation technology, the activity concentrations, the amounts of residue generated and the regional eco-environmental features. Some conclusions and suggestions on the disposal of these NORM residues are given, with reference to the relevant national laws, regulations and standards. (author)

  17. Growth of rare earth garnet layers by liquid phase epitaxy

    Czech Academy of Sciences Publication Activity Database

    Nitsch, Karel; Cihlář, Antonín; Rodová, Miroslava; Král, Robert

    Bratislava: N, 2009 - (Koman, M.; Mikloš, D.), s. 54-55 ISBN 978-80-89088-81-2. [Development of Materials Science in Research and Education - DMS -RE 2009 /19./. Závažná Poruba (SK), 31.08.2009-04.09.2009] R&D Projects: GA AV ČR KAN300100802 Institutional research plan: CEZ:AV0Z10100521 Keywords : LPE * rare earth aluminium garnet layers * scintillation Subject RIV: BM - Solid Matter Physics ; Magnetism

  18. Rare earth(3) nitrates extraction with trialkylmethylammonium nitrate in toluene

    International Nuclear Information System (INIS)

    Extraction of rare earth(3) nitrates [praseodymium(3)-lutetium(3)] with trialkylmethylammonium nitrate in toluene at T = 298.15 K and pH 2 is studied. Extraction isotherms are described with regard to formation of compounds of (R4N)i[Ln(NO3)3+i] composition (i = 2, 3) in organic phase. Values of extraction constants are calculated, they are decreasing in the praseodymium(3) - lutetium(3) series

  19. Rare earth elements and oxides in liquid phase epitaxy

    Czech Academy of Sciences Publication Activity Database

    Procházková, Olga; Grym, Jan; Zavadil, Jiří; Kopecká, M.

    2006-01-01

    Roč. 100, č. 8 (2006), s. 640--. ISSN 0009-2770. [Sjezd chemických společností /58./. Ústí nad Labem, 04.09.2006-08.09.2006] R&D Projects: GA ČR(CZ) GA102/06/0153 Institutional research plan: CEZ:AV0Z20670512 Keywords : semiconductor technology * rare earth metals Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.431, year: 2006

  20. Neutron diffraction studies of rare-earth doped borate glasses

    International Nuclear Information System (INIS)

    Rare-earth ions included in glassy host networks have been studied as prototype systems for nuclear waste management. They are known to exhibit well defined absorptions in the visible region. Optical studies of glasses doped with two different rare-earth ions have been shown to display absorption spectra that are linear combinations of the component rare-earths appropriately weighted by their relative proportions in the glass. Investigations of local structure by diffraction methods may lead to an understanding of the origin of such rare-earth ion interactions. A set of borate glasses have been prepared in which Nd and Pr ions were included in the relative proportions of 1:3 and 3:1 for the two ions. Alumina was added (5 mole%) for ease of preparation and the borate component was 75%. The glasses were quenched in air at room temperature. The host glass was prepared from 11B boric acid for the neutron diffraction measurements. The data presented here were from X-ray diffraction (CuKα Rigaku D-MAX/B rotating anode) and neutron diffraction using the High Q diffractometer at Dhruva Reactor, B.A.R.C., For both types of measurement, the glasses were crushed to fine powders. The neutron data were collected with the powders in 6 mm diameter, 5 cm high vanadium cans. The structure factors of both glasses and that for the undoped borate glass from the neutron diffraction data are shown. The total correlation functions T(r) are displayed. The presence of the R-O correlations may be observed at about 3.2 Å. Separations of these correlations from both X-ray and neutron data will be presented. (author)

  1. X-ray dichroism of rare earth materials

    International Nuclear Information System (INIS)

    The theme of this thesis is the investigation of the strong polarization dependende, or dichroism, that occur in the X-ray absorption spectra of rare earth materials. The rare earth elements distinguish themselves from the other elements through the behaviour of the 4f electrons which form the valence shell. This shell lies deep inside the atom, with the result that influences from the surrounding solid are well screened off by the outer electrons, so that even in the solid the 4f shell behaves very much like a in free atom or ion, and is almost completely spherically symmetric. Perturbations from the solid environment however always disturb this symmetry to some extend, with the result that the absorption spectrum becomes dependent on the mutual orientation of the polarization vector of the radiation and the ion. Earlier the existence of a strong magnetic X-ray dichroism (MXD) in the 3d→4f transitions of rare earths. In this thesis this work is extended, to a small degree theoretically but mainly experimentally. MXD is used in experiments on bulk sample, terbium iron garnet, and on rare earth overlayers on a ferromagnetic surface, Ni(110). The results of the latter study show unequivocally the potential of the MXD technique. The second theme of the thesis concerns experimental developments in soft X-ray spectroscopy. A description is given of a double crystal monochromator beamline that was constructed by our group at LURE, France. Results of the use of an organic crystal - multilayer comination in such a monochromator is described. Also a method is described for the characterization of the resolution of soft X-ray monochromators. Finally a contribution to the characterization of the electron yield technique in the soft X-ray range is given. (author). 296 refs.; 64 figs.; 59 schemes; 9 tabs

  2. Rare-Earth Doped Nanocrystalline Phosphors for Field Emission Displays

    Directory of Open Access Journals (Sweden)

    P. Psuja

    2007-01-01

    Full Text Available The cathodoluminescence properties of rare-earth (RE = Ce, Eu, Tb doped nanocrystalline phosphors (Y2O3, Y3Al5O12 were investigated. Their structure and morphology were determined and correlated with optical properties. The effect of grain sizes on emission yield of RE doped nanophosphors has been investigated. A possibility of application of RE doped nanophosphors for efficient field emission display (FED devices has been discussed.

  3. Magnetostatic Effects in the Nucleation of Rare Earth Ferromagnetic Phases

    Energy Technology Data Exchange (ETDEWEB)

    Durfee, C. S.; Flynn, C. P.

    2001-07-30

    It has been reported that superheating, supercooling, and explosive kinetics coupled to other degrees of freedom occur at the ferromagnetic transitions of Er and Dy, and that metastable phases occur during the transition kinetics of Er. We explain these observations in terms of magnetostatic energy, which requires highly eccentric nuclei in the homogeneous nucleation of magnetic transitions in heavy rare earths. The magnetostatics favor transitions through ferrimagnetic intermediaries. The unusual kinetics derive from effective spin lattice relaxation.

  4. NEUTRON DIFFRACTION STUDIES OF RARE EARTH IONS IN GLASSES

    OpenAIRE

    Wright, A; Etherington, G.; Erwin Desa, J.; Sinclair, R.

    1982-01-01

    The environment of the rare earth ions in vitreous Sm2O3-Al2O3-GeO2 has been studied using the neutron diffraction anomalous dispersion technique and that in vitreous NaF-DyF3-BeF2 by isotopic substitution. The mean Sm-O and Dy-F distances are 2.420 and 2.301 Å respectively.

  5. Rare-earth doped chalcogenide glass fibre laser

    OpenAIRE

    Schweizer, T.; Samson, B.N.; Moore, R C; Hewak, D.W.; Payne, D.N.

    1997-01-01

    We report on the first laser action in a rare-earth doped chalcogenide glass fibre. Laser action at 1080nm was obtained in a 22mm long gallium lanthanum sulphide glass fibre with a neodymium doped core, fabricated by the rod-in-tube technique. The laser was pumped continuous wave with a Ti:sapphire laser at 815nm and showed a self-pulsing behaviour.

  6. Trade Group Rules Against China in Rare Earths Dispute

    Science.gov (United States)

    Showstack, Randy

    2014-04-01

    The World Trade Organization (WTO) has ruled against China in a trade dispute over rare earth elements (REE) as well as tungsten and molybdenum, the group announced on 26 March. The European Union, Japan, and the United States brought trade cases against China in March 2012 concerning alleged unfair export restraints on the materials (see Eos, 93(13), 134-135, doi:10.1029/2012EO130002).

  7. Alternatives to Rare Earth Permanent Magnets for Energy Harvesting Applications

    Science.gov (United States)

    Khazdozian, Helena; Hadimani, Ravi; Jiles, David

    Direct-drive permanent magnet generators (DDPMGs) offer increased reliability and efficiency over the more commonly used geared doubly-fed induction generator, yet are only employed in less than 1 percent of utility scale wind turbines in the U.S. One major barrier to increased deployment of DDPMGs in the U.S. wind industry is NdFeB permanent magnets (PMs), which contain critical rare earth elements Nd and Dy. To allow for the use of rare earth free PMs, the magnetic loading, defined as the average magnetic flux density over the rotor surface, must be maintained. Halbach cylinders are employed in 3.5kW Halbach PMGs (HPMGs) of varying slot-to-pole ratio to concentrate the magnetic flux output by a lower energy density PM over the rotor surface. We found that for high pole and slot number, the increase in magnetic loading is sufficient to allow for the use of strontium iron oxide hard ferrite PMs and achieved rated performance. Joule losses in the stator windings were found to increase for the hard ferrite PMs due to increased inductance in the stator windings. However, for scaling of the HPMG designs to 3MW, rated performance and high efficiency were achieved, demonstrating the potential for elimination for rare earth PMs in commercial scale wind turbines. This work was supported by the National Science Foundation under Grant No. 1069283 and a Barbara and James Palmer Endowment at Iowa State University.

  8. On the solubility of rare earth fluorides in mineral acids

    International Nuclear Information System (INIS)

    The results of the investigation of rare earth fluoride solubility in a wide range of nitric acid concentrations are presented. The fluoride solubility monotonously increases with the nitric acid concentration and upon attaining a certain maximum again decreases. The maximum solubility region for all fluorides studied is located in definite concentration limits of the acid. The YF3 these values correspond to 2.0 g/l, for NdF3-2.32, SmF3 -2.25, PrF3 - 0.72, EuF3 - 1.66 g/l within the limits of 3.1-6.0 mol/l of nitric acid. Such course of the solubility curve is bound up with the change of hydrogen ion concentration in the solution. Solubility product values have been obtained for rare earth fluorides in the HNO3 concentration range from 0.42 to 1.3 mol/l. It is shown that rare earth fluorides have low solubility product values in nitric acid and their solubility product values depend on hydrogen ion concentration

  9. The systematics of thermoluminescence in rare earth activated sulfate lattices

    International Nuclear Information System (INIS)

    A systematic survey of the thermoluminescence (TL) of rare earth activated sulfates of Be, Mg, Ca, Sr, Ba, Zn, Cd, and Pb was made. The sulfates of Sr, Ba, and Cd (as well as Ca) were found to exhibit an extremely bright TL following gamma irradiation, many of the phosphors being comparable in efficiency to CaSO4:Dy (Harshaw). The temperature of the glow peak induced by a rare earth ion in a given lattice was found to be determined only by the valence state of the rare earth. A decrease in trap depth with increasing lattice spacing was also observed. The most sensitive of these new phosphors are SrSO4:Tb3+ and BaSO4:Eu2+. Due to their relatively high-Z and large efficiency, these phosphors could prove useful as quality indicators for personnel dosimetry or for detecting very small exposures of low-energy x-rays (of a known quality). The TL properties of interest in dosimetry were determined for these phosphors. (author)

  10. Magnetism of perovskite cobaltites with Kramers rare-earth ions

    Energy Technology Data Exchange (ETDEWEB)

    Jirák, Z., E-mail: jirak@fzu.cz; Hejtmánek, J.; Knížek, K.; Novák, P.; Šantavá, E. [Institute of Physics ASCR, Cukrovarnická 10, 162 00 Prague 6 (Czech Republic); Fujishiro, H. [Faculty of Engineering, Iwate University, Morioka 020-8551 (Japan)

    2014-05-07

    The band-gap insulators RECoO{sub 3} (RE = Nd{sup 3+}, Sm{sup 3+}, and Dy{sup 3+}) with Co{sup 3+} ions stabilized in the non-magnetic low-spin state have been investigated by specific heat measurements. The experiments evidence an antiferromagnetic ordering of the rare earths with Néel temperature of T{sub N} = 1.25, 1.50, and 3.60 K for NdCoO{sub 3}, SmCoO{sub 3}, and DyCoO{sub 3}, respectively. With increasing external field, the lambda peak in specific heat, indicative of the transition, shifts to lower temperatures and vanishes for field of about 3 T. Starting from this point, a broader Schottky peak is formed, centered in 1 K range, and its position is moved to higher temperatures proportionally to applied field. The origin of the peak is in Zeeman splitting of the ground Kramers doublet, and the gradual shift with field defines effective g-factors for the rare-earth pseudospins in studied compounds. The results obtained are confronted with the calculations of crystal field splitting of the rare-earth multiplets.

  11. Volatility and thermal stabilty of rare earth pivaloiltrifluoroacetonates

    International Nuclear Information System (INIS)

    Thermal stability of pivaloltrifluoroacetonates of rare earth metals (Ln(PTA)3) and the influence of their hydrate composition on the volatility and thermal stability of complexes have been investigated, tris-Chelates have been obtained by the interaction of HPTA (C8H11O2F3) with salts of rare earth metals in the neutral homogeneous or heterogeneous medium. The structure of synthethized complexes corresponds to Ln(PTA)3xnH2o (n=1, 2). The products have been dried in vacuum in presence of P2O5. The investigation of the volatility and thermal stability of obtained compounds has been made by means of thermogravimetrical and differentially-thermal analysis together with mass-spectrometry data. The increase of volatility of anhydrous complexes in the series from La to Lu being characteristical for compounds of rare earth metals have been established. The evaporation of the great part of complexes has been occurred with partial decomposition. The role of the latter process decreases from La to Lu compounds. The presence of water in complexes leads to substantial decrease in the volatility and thermal stability of dihydrates. Monohydrates of the complexes of higher lanthanoids have been found to dehydrate and evaporate practically without residue and decomposition

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

    CERN Document Server

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

    2016-01-01

    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...

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

    Science.gov (United States)

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

    2015-11-01

    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. PMID:26139395

  14. Social and Environmental Impact of the Rare Earth Industries

    Directory of Open Access Journals (Sweden)

    Saleem H. Ali

    2014-02-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    梁鹏; 张艺; 汪东风; 徐莹; 罗斓

    2013-01-01

    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.

  16. Novel precursors for the deposition of rare earth oxides

    International Nuclear Information System (INIS)

    During this work rare earth solvates with nitrate and perchlorate anions have been investigated. All compounds have been structurally characterized and analyzed using thermal gravimetric analysis. The decomposition residues were analyzed using powder diffraction methods. Almost all compounds showed a characteristically intense exothermic decomposition step during the thermal decomposition, most likely caused by an intramolecular redox reaction between the nitrate or perchlorate anion respectively and the organic solvent molecules. The nitrates RE(NO3)3(CH(OCH3)3)2 (RE = Sm, Eu) were isolated and characterized for the first time as the intermediate of the dehydration reaction with trimethyl orthoformate. The known compound group of dimethoxyethane solvates was then expanded with RE(NO3)3(O2C4H10) (RE = La, Sm, Eu). Considering the possible use as precursor material the already described neodymium compound is also discussed. The thermal decomposition of these compounds yields the respective cubic rare earth oxide and shows the typical intense exothermic decomposition reaction. A variety of different precursor system based on nitrate solvates for the deposition of rare earth oxide layers on a silicon surface was developed and investigated in collaboration with the group of Prof. Dr. Al-Shamery (Univ. Oldenburg). Ultra thin films on a H-Si(111) surface were obtained via the deposition of the precursor, which was dissolved in organic solvents. An oxide layer was detected after the heating of the sample. The film thickness was measured as < 10 nm, whereas the thickness of the film was controlled by the concentration of the precursor solution. Sm(ClO4)3(CH(OCH3)3)3 was isolated and characterized for the first time as the intermediate of the dehydration reaction with trimethyl orthoformate. Eu(ClO4)3(CH(OCH3)3)2(MeOH)2 was obtained without recrystallization. The methanol molecules, formed during the hydrolysis of the trimethyl orthoformate, were not fully replaced by the

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

    Institute of Scientific and Technical Information of China (English)

    YAN Kai; ZHEN Qiang; Song Xiwen

    2007-01-01

    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.

  18. Geochemistry of rare earths in main media of clay formation and sedimentation

    International Nuclear Information System (INIS)

    This work aims i) at a better knowledge of rare earth behavior in surface conditions and ii) possible use of rare earth as a marker for argilaceous mineral genesis. Chemical properties of rare earths and geochemistry of these elements in main rocks are recalled. Rare earth behaviour during continental alteration process, experimental hydrolysis of various magmatic materials and rare earth geochemistry in argilaceous minerals in continental shelf are examined. Then some aspects of rare earth behaviour in oceans are studied: alteration of sea bed and hydrothermalism rare earth distribution in pelagic sediments red clays of deep seas and manganese nodules. In conclusion rare earth behaviour in sedimentary processes of the exogenous cycle is summarized

  19. The study of mutual influence of rare earth(3) ions during their extraction with tri-n-butylphosphate from multicomponent nitrate solutions

    International Nuclear Information System (INIS)

    Extraction of yttrium subgroup rare earth metal(3) nitrates and yttrium(3) nitrate from multicomponent solutions of tri-n-butylphosphate at T = 298.15 K and pH = 2 was considered. Physicochemical and mathematical models, describing the distribution and mutual effect of lanthanides (samarium-lutetium) and yttrium(3) in the multicomponent solutions, depending on total concentration of rare earth metal ions in aqueous phase and composition of concentrates, are given

  20. Synthetic Investigations in Rare-Earth Borates, Gallates, Oxides, and Gallium Oxonitrides at Extreme Conditions

    OpenAIRE

    Hering, Stefanie Alexandra

    2010-01-01

    The present phD thesis concerns synthetic investigations under extreme conditions of high-temperature and high-pressure. The high-temperature / high-pressure experiments, performed using a multianvil high-pressure device, led to the first single crystals of various rare-earth gallates, rare-earth borates, rare-earth oxides and gallium oxonitrides.

  1. 77 FR 58578 - Certain Sintered Rare Earth Magnets, Methods of Making Same and Products Containing Same...

    Science.gov (United States)

    2012-09-21

    ... COMMISSION Certain Sintered Rare Earth Magnets, Methods of Making Same and Products Containing Same... the sale within the United States after importation of certain sintered rare earth magnets, methods of... after importation of certain sintered rare earth magnets, methods of making same and products...

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

    OpenAIRE

    Cramer, A.J.; J. M. Cole; FitzGerald, V.; Honkimaki, V.; Roberts, M A; Brennan, T.; Martin, R A; Saunders, G. A.; Newport, Robert J

    2013-01-01

    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(P2O 5)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, RP 5O14. Thereupon, the effects of rare-earth co-dopin...

  3. Rare earths in electroluminescent and field emission display phosphors

    International Nuclear Information System (INIS)

    Monochrome electroluminescent flat panel displays based on ZnS:Mn have commercially been available for several years and now multicolor devices are coming to the market. Colors are usually produced by rare earth activators in ZnS or alkaline earth sulfide matrices. The materials studied include ZnS:Tb, ZnS:Sm, ZnS:Tm, CaS:Eu, CaS:Tb, SrS:Ce and thiogallates (Ca, Sr)Ga2S4 doped with Ce or Eu. The most promising approach to full color devices is that with ZnS:Mn (yellow) and SrS:Ce (blue-green) broad band phosphors and color filters. Field emission displays (FED) are based on cathodoluminescence where the electrons used in excitation originate from an addressable array of microtip cathodes. The operation voltage can vary (300 V-8 kV) but green emitting ZnO:Zn is so far the only phosphor which gives applicable luminance efficiency at low voltages. The problems in FED phosphors and the results obtained with rare earth containing phosphors are reviewed. (orig.)

  4. Study on Yen Phu rare earth ore concentrate treatment technology and separation of major heavy rare earth elements by solvent extraction method

    International Nuclear Information System (INIS)

    Aliquat 336 systems have been optimized using the computer simulation program. The solution containing > 80% pure Y2O3 after upgrading by PC88A (18 extraction, 18 scrubbing and 10 stripping stages) is purified further by another cycle of SX (24 extraction, 10 scrubbing and 10 stripping stages) with 25% Aliquat 336 in kerosene in presence of 1.0 M NH4SCN and 2.0 M NH4Cl. The impurities of Ho, Er, and another heavy elements are extracted leaving >99.9% pure Y2O3 in the aqueous phase. The yield of the process is > 85%. 4. Separation and purification of europium: The isolation and purification of europium consists of following steps: isolation of Eu by reduction on zinc column and precipitation in the form EuSO4 by H2SO4 under CO2 atmosphere; first purification by conversion of EuSO4 to EuCl3, reduction and precipitation in the form EuSO4; and second purification by reduction on zinc column and precipitation of other rare earth elements in the form RE(OH)3 by NH4Cl-NH4OH buffer of pH = 10 under atmosphere N2. Eu2O3 of 99.9% purity has been recovered with overall yield. 5. Separation and purification of gadolinium: The middle subgroup after Eu removing is subject to Gd recovery by SX with PC88A. The SX parameters for Gd separation had been optimized by computer program. The separation process consists of 12 extraction, 12 scrubbing and 6 stripping stages. The acidity of scrubbing solution is 1.0.M HCl. The purity and yield of the Gd separation process were > 98% and >85% respectively. The obtained Gd2O3 was purified by Eu removing using zinc column and H2SO4. The final purity of the Gd2O3 was reached value 99%. 6. Overall schema for individual separation of some rare earth elements of high purity from Yenphu rare earth ore concentrate: Based on the above obtained results, overall schema for individual separation of some rare earth elements (Y, Gd, Eu and Sm) of high purity from Yenphu rare earth ore concentrate has been proposed. The schema consists of REE ore concentrate

  5. Radiation effects on rare-earth doped optical fibers

    International Nuclear Information System (INIS)

    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 (Er3+ and/or Yb3+) 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)

  6. Study of rare earth elements as material for control rods

    International Nuclear Information System (INIS)

    The properties of rare earth elements as the material for control rods were studied. The rare earth elements, especially europium oxide, has the nuclear property corresponding to boron carbide, and its neutron absorption process does not emit alpha particles. The elements produced as a result of neutron capture also have large capture cross sections. This paper presents survey report on the properties and nuclear properties of rare earth elements, and comparison with other materials. Preliminary experiment was performed to make the pellets of europium oxide, and is described in this paper. Because of large density, the crystal form to be made was monoclinic system. Europium hydroxide was decomposed at 10000C and 10-5 torr. The obtained powder was dipped into benzene, and dryed in the air at 4500C. This powder was pressed and sintered in the air for one hour at 15000C. The density of the obtained pellets was 97.0% of the theoretical density. The cross section of europium for fast neutron absorption is not yet accurately obtained, and is in the range between 4.65 and 8.5 barn for 151Eu(n,γ) reaction. Since chain absorption reaction is caused in Eu, the overall capability of neutron absorption is not much changed by the loss of original material due to absorption. The pellets of europium oxide may be handled in air, but must be kept in dry atmosphere. The reactions of europium oxide with various metals were also investigated. The characteristic behavior in case of irradiation depends on the amount of silicon contained, and it was very good if the amount was less than 0.03%. (Kato, T.)

  7. Transition Probabilities of the Rare Earth Neutral Lanthanum

    Science.gov (United States)

    Palmer, Andria; Lawler, James E.; Den Hartog, Elizabeth

    2015-01-01

    In continuation of a long-standing project to measure transition probabilities for rare earth elements, La i is currently being studied. Transition probabilities of the rare earths and other elements are determined in order to assist astronomers in making stellar spectroscopy more quantitative. Atomic spectroscopy is a key tool for astronomers as it provides nearly all the details about the physics and chemistry of the universe outside of our solar system. Rare earth elements tend to have complex electronic structure due to their open 4f, 5d, 6s, and 6p shells. This leads to a rich spectrum throughout the ultraviolet, visible and near-infrared, making them very accessible elements for study in stellar photospheric spectra. A transition probability is the probability per unit time for a transition to occur between an upper level and a lower level. The process for measuring transition probabilities is by using the well-established technique of time-resolved laser-induced fluorescence to measure the radiative lifetimes for each upper level. This is then combined with branching fractions measured using a 1m high-resolution Fourier Transform Spectrometer. Radiative lifetimes for ~70 upper levels of neutral La along with their associated branching fractions will be reported, resulting in the determination of several hundred new transition probabilities. These transition probabilities will assist astronomers in analyzing the chemical compositions of older, cooler stars which give insight into the origins of the chemical elements.This work supported by by NSF grant AST-1211055 (JEL & EDH) and by the NSF REU program (AJP).

  8. High purity neodymium acetate from mixed rare earth carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Carlos A. da Silva; Rocha, Soraya M. Rizzo da; Vasconcellos, Mari E. de; Lobo, Raquel M.; Seneda, Jose A., E-mail: cqueiroz@ipen.b, E-mail: smrrocha@ipen.b, E-mail: mstela@ipen.b, E-mail: rmlobo@ipen.b, E-mail: jaseneda@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Pedreira, Walter dos R., E-mail: walter.pedreira@fundacentro.gov.b [Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho (FUNDACENTRO), Sao Paulo, SP (Brazil)

    2011-07-01

    A simple and economical chemical process for obtaining high purity neodymium acetate is discussed. The raw material in the form rare earth carbonate is produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography technique with a strong cationic resin, proper to water treatment, and without the use of retention ions was used for the fractionating of the rare earth elements (REE). In this way, it was possible to obtain 99.9% pure Nd{sub 2}O{sub 3} in yields greater than or equal 80%, with the elution of the REE using ammonium salt of ethylenediaminetetraacetic acid (EDTA) solution in pH controlled. The complex of EDTA-neodymium was transformed into neodymium oxide, which was subsequently dissolved in acetic acid to obtain the neodymium acetates. Molecular absorption spectrophotometry was used to monitor the neodymium content during the process and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the neodymium acetates. The typical neodymium acetates obtained contain the followings contaminants in {mu}g g{sup -1}: Sc(5.1); Y (0.9); La (1.0); Ce (6.1); Pr (34,4); Sm (12.8); Eu (1.1); Gd (15.4); Tb (29.3); Dy (5.2), Ho(7.4); Er (14.6); Tm (0.3); Yb (2.5); Lu (1.0). The high purity neodymium acetates obtained from this procedure have been applied, replacing the imported product, in research and development area on rare earth catalysts. (author)

  9. Phase transitions in rare earth tellurides under pressure

    International Nuclear Information System (INIS)

    Using first-principles calculations we have studied the valence and structural transitions of the rare earth monotellurides RTe (R = Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb) under pressure. The self-interaction corrected local spin-density approximation is used to establish the ground state valence configuration as a function of volume for the RTe in both the NaCl (B1) and CsCl (B2) structures. We find that in ambient conditions all the RTe are stabilized in the B1 structure. A trivalent (R3+) rare earth ground state is predicted for the majority of the RTe, with the exception of SmTe, EuTe, DyTe, TmTe and YbTe, where the fully localized divalent (R2+) rare earth configuration is found to be energetically most favourable. Under pressure, the trivalent RTe undergo structural transitions to the B2 structure without associated valence transition. The divalent RTe on the other hand are characterized by a competition between the structural and electronic degrees of freedom, and it is the degree of f-electron delocalization that determines the sequence of phase transitions. In EuTe and YbTe, where respectively the half-filled and filled shells result in a very stable divalent configuration, we find that it is the structural B1 → B2 transition that occurs first, followed by the R2+ → R3+ valence transition at even higher pressures. In SmTe, DyTe and TmTe, the electronic transition occurs prior to the structural transition. With the exception of YbTe, the calculated transition pressures are found to be in good agreement with experiment. (paper)

  10. Colorimetric determination of manganese in rare earth compounds

    International Nuclear Information System (INIS)

    A way of Mn microimpurity determination in rare earths and their oxides with an exception of cerium is suggested. The method is based on preliminary Mn impurity concentration by means of flocculation of colloid solutions of manganese diethyldithiocarbaminate and thioxinate with an aid of polyacrylamide. The impurity concentrate is mineralized and then Mn is determined by standard permanganate procedure. 1000-multiple quantities of Al, Cr, Cu, Fe, Ni, Pb, Ti, V do not influence Mn determination. The detection limit is 5x10-6%

  11. Preparation of Rare-Earth Composite Ferrite Magnetic Fluid

    Institute of Scientific and Technical Information of China (English)

    蒋荣立; 刘永超; 刘守坤; 鞠明礼

    2004-01-01

    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.

  12. Resonance electronic Raman scattering in rare earth crystals

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G.M.

    1988-11-10

    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.

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

    Institute of Scientific and Technical Information of China (English)

    张自立; 常江; 等

    2002-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    张自立; 常江; 汪成胜; 柴绍明; 韩修明; 李瑞

    2002-01-01

    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.

  15. Rare earth elements distribution in marine sediments of Malaysia coasts

    Institute of Scientific and Technical Information of China (English)

    Rezaee; Ebrahim; Saraee; Khadijeh; Saion; B.Elias; Abdul; Khalik; Wood; Abdi; Mohammad; Reza

    2009-01-01

    In the east coast Peninsular Malaysia region,sediments are transported by several rivers from the east Malaysia into the South China Sea estuary.In the vicinity of the five river estuaries core sediments were collected in order to investigate rare earth elements(REEs) profile.Core sediments were divided into strata of between 2 to 4 cm intervals and prepared for analyzing by ICP-AES.REE concentrations of 54.3 μg/gr at 24-26 cm in EC4 increased to 114.1 μg/gr at 20-22 cm in EC5.The measured concentration of ...

  16. Rare-earth magnets and their applications. Vol. 2. Proceedings

    International Nuclear Information System (INIS)

    The following topics were dealt with: permanent magnets, rare- earth magnets, manufacturing, markets, powder metallurgy, sintering, mechanical alloying, nanocrystalline magnets, Curie temperature, domain structure, exchange coupling, stoichiometry effects, coercive force, remanence, magnetisation distribution, demagnetisation, mechanical properties, deformation behaviour, microstructure, grain size effects, texture, magnetic anisotropy, hydrogen assisted processing, nitriding, hydrogen embrittlement, permanent magnet motors, permanent magnet generators, brushless machines, linear motors, DC motors, AC motors, servomotors, magnetic levitation, magnetic field calculations, magnetic damping, magnet system design, system optimisation, corrosion protection, magnetometers, hard magnetic films, magnetostriction, magnetic multilayers, spin glass behaviour

  17. Rare-earth elements in recent calcareous benthic organisms

    International Nuclear Information System (INIS)

    Fresh and aged samples of foraminifera and red algae from two different climatic areas (the Great Barrier Reefs of Australia and the northwestern Mediterranean Sea) were analyzed by non-destructive thermal and epithermal neutron activation for some traces and rare-earth elements (REE). Mechanisms were tentatively proposed to explain the measured distributional differences: iron scavenging effect, microbial intervention at given stages of very early diagenesis, feeding behaviour organisms... REE and traces follow increases of of iron content during biodiagenesis; this process does not apparently originate discrimination in the distributional pattern of Ree. Eu negative and Ce positive anomalies were recorded in types of organisms; these anomalies were explained by bioprocesses. (author)

  18. Rare-earth elements in recent calcareous benthic organisms

    International Nuclear Information System (INIS)

    Fresh and aged samples of foraminifera and red algae from two different climatic areas (Australia and the Mediterranean Sea) were analyzed by non-destructive thermal and epithermal neutron activation for some traces and rare-earth elements (REE). Mechanisms were tentatively proposed to explain the measured distributional differences: iron scavenging effect, microbial intervention at given stages of very early diagenesis, feeding behaviour of organisms. REE and traces follow increases of iron content during biodiagenesis; this process does not apparently originate discrimination in the distributional pattern of REE. (author)

  19. A fast dynamic mode in rare earth based glasses.

    Science.gov (United States)

    Zhao, L Z; Xue, R J; Zhu, Z G; Ngai, K L; Wang, W H; Bai, H Y

    2016-05-28

    Metallic glasses (MGs) usually exhibit only slow β-relaxation peak, and the signature of the fast dynamic is challenging to be observed experimentally in MGs. We report a general and unusual fast dynamic mode in a series of rare earth based MGs manifested as a distinct fast β'-relaxation peak in addition to slow β-relaxation and α-relaxation peaks. We show that the activation energy of the fast β'-relaxation is about 12RTg and is equivalent to the activation of localized flow event. The coupling of these dynamic processes as well as their relationship with glass transition and structural heterogeneity is discussed. PMID:27250316

  20. Anomalous Hall Effect in a Feromagnetic Rare-Earth Cobalite

    Science.gov (United States)

    Samoilov, A. V.; Yeh, N. C.; Vasquez, R. P.

    1996-01-01

    Rare-Earth manganites and cobalites with the perovskite structure have been a subject of great recent interest because their electrical resistance changes significantly when a magnetic field is applied...we have studied the Hall effect in thin film La(sub 0.5)Ca(sub 0.5)CoO(sub 3) material and have obtained convincing evidence fo the so called anomalous Hall effect, typical for magnetic metals...Our results suggest that near the ferromagnetic ordering temperature, the dominant electron scattering mechanism is the spin fluctuation.

  1. Investigation of anodic behaviour of rare earth amalgams

    International Nuclear Information System (INIS)

    Using the method of anode decomposition at a constant potential the electrochemical behaviour is investigated of amalgams of rare-earth metals (REM): lanthanum, cerium, praseodymium, neodymium, gadolinium, terbium, dysprosium, holmium, and erbium. It has been established that on reduction of REM, a finely dispersed powder of an intermetallic compound of an approximate composition RHg is formed on mercury. On ageing of amalgams of lanthanum and metals of the cerium group this intermetallic compound undergoes phase transformations. In the case of metals of the yttrium group this intermetallide loses its wettability and floats up on the mercury surface

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

    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.

  3. Unlocking the potential of Rare Earth Resources in Europe

    OpenAIRE

    Arvaniditis, Nikolaos; Goodenough, Kathryn

    2014-01-01

    During the last decade the non‐energy raw materials have become part of the EU’s new industrial strategy and growth agenda, with increased funding opportunities in the field of mineral resources. The four‐year (2009–2013) ProMine project has provided a well documented knowledge base of Europe's non‐energy raw material resource potential. The ongoing EURARE project is focused on enhancing the value chain perspectives for European Rare Earth Elements (REE) and the Minerals 4EU pr...

  4. Rare earth element patterns in biotite, muscovite, and tourmaline minerals

    International Nuclear Information System (INIS)

    Rare earth element concentrations in the minerals biotite and muscovite from the mica schist country rocks of the Etta pegmatite and tourmalines from the Bob Ingersoll pegmatite have been measured by INAA and CNAA. The concentrations range from 10-4 g/g to 10010 g/g/. The Ree patterns of biotite, muscovite and tourmaline reported herin are highly fractionated from light to heavy REE. The REE concentrations in biotite and muscovite are high and indigenous. The pegmatite tourmalines contain low concentrations of REE. Variations in tourmaline REE patterns reflect the geochemical evolution of pegmatite mel/fluid system during crystallization. (author)

  5. Rare earth element patterns in biotite, muscovite and tourmaline minerals

    International Nuclear Information System (INIS)

    Rare earth element concentrations in the minerals biotite and muscovite from the mica schist country rocks of the Etta pegmatite and tourmalines from the Bob Ingersoll pegmatite have been measured by INAA and CNAA. The concentrations range from 10-4 g/g to 10/sup -10g//sub g/. The REE patterns of biotite, muscovite and tourmaline reported herein are highly fractionated from light to heavy REE. The REE concentrations in biotite and muscovite are high and indigenous. The pegmatite tourmalines contain low concentrations of REE. Variations in tourmaline REE patterns reflect the geochemical evolution of pegmatite melt/fluid system during crystallization

  6. Thermoluminescence dosimetry of rare earth doped calcium aluminate phosphors

    Indian Academy of Sciences (India)

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

    2006-04-01

    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.

  7. Recent Progress on Nanoscale Rare Earth Luminescent Materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    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 element content of cryptocrystalline magnesites of Konya, Turkey

    Science.gov (United States)

    Zedef, Veysel; Russell, Michael

    2016-04-01

    We examined the rare earth element content of several cryptocrystalline magnesites as well as hydromagnesite, host rock serpentinites, lake water and hot spring water from Turkey. Southwestern Turkey hosts cryptocrystalline magnesites, sedimentary magnesites with presently forming, biologically mediated hydromagnesites and travertines. Our results show the REE content of the minerals, rocks and waters are well below detection limits. One hydromagnesite sample from Lake Salda has slightly high La (2.38ppb), Ce (3.91 ppb) and Nd (1.68 ppb) when compared to other samples, but these are also still below detection limits of the method we followed.

  9. Rare-earth pnictides and chalcogenides from first-principles.

    Science.gov (United States)

    Petit, L; Szotek, Z; Lüders, M; Svane, A

    2016-06-01

    This review tries to establish what is the current understanding of the rare-earth monopnictides and monochalcogenides from first principles. The rock salt structure is assumed for all the compounds in the calculations and wherever possible the electronic structure/properties of these compounds, as obtained from different ab initio methods, are compared and their relation to the experimental evidence is discussed. The established findings are summarised in a set of conclusions and provide outlook for future study and possible design of new materials. PMID:27165563

  10. Resonance electronic Raman scattering in rare earth crystals

    International Nuclear Information System (INIS)

    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: Ce3+(4f1) in single crystals of LuPO4 and Er3+(4f11) in single crystals of ErPO4. 134 refs., 92 figs., 33 tabs

  11. Spectra of fluorinated rare earth. beta. -diketonates with added ligands

    Energy Technology Data Exchange (ETDEWEB)

    Khomenko, V.S.; Lozinskij, M.O.; Fialkov, Yu.A.; Rasshinina, T.A.; Krasovskaya, L.I. (AN Belorusskoj SSR, Minsk. Inst. Fiziki; AN Ukrainskoj SSR, Kiev. Inst. Organicheskoj Khimii)

    1984-01-01

    Different-ligand rare earth complexes are synthesized. Fluorated ..beta..-diketones, triethylphosphine oxide and trifluoracetic acid are used as active ligands. Mass-spectra of low and high resolution are taken at the energy of ionizing electrons of 70 eV, as well as luminescence spectra of complexes. Fragmentation ways of complexes decomposition under electron shock are studied. A series of changing the bound strength of additional ligands with europium in mixed complexes is determined. It is shown that the introduction of additional ligands can purposefully change physical and chemical properties of complexes.

  12. Marine geochemistry of the rare earth elements: a review

    International Nuclear Information System (INIS)

    The rare earth elements (REE) form a coherent group because of their systematic decrease in atomic radii with increasing atomic number and predominant +3 oxidation state. This makes them particularly useful in the study of marine geochemistry. The fact that two members of the group are often found in anomalous oxidation states allows a study of the fractionation of these REE from their neighbours and provides an insight into the geochemical behaviour of the REE in the marine environment. Thus the chemistry and relative abundances of the REE can be used to assess the origin and depositional environments of modern sediments. (author)

  13. Concept of separation technology for rare earth elements

    International Nuclear Information System (INIS)

    The initial raw material for the designed separation of rare earth elements were flotation concetrates of bastnaesite ore from the Vietnamese Socialist Republic or phosphate concentrates produced during the manufacture of NPK fertilizer from the Kola apatite. A unified hydrometallurgical method shown in the figure was suggested for the reprocessing of the said concentrates. Liquid concentrate with a low content of Ce, without Th and with minimum content of fluorides enters the extraction separation: Di-2-ethylhexylphosphoric acid is used as the extraction agent. (E.S.). 1 fig

  14. Small hole polarons in rare-earth titanates

    International Nuclear Information System (INIS)

    We investigate the behavior of hole polarons in rare-earth titanates by combining optical conductivity measurements with first-principles hybrid density functional calculations. Sr-doped GdTiO3 (Gd1−xSrxTiO3) was grown by molecular beam epitaxy. We show that a feature in the optical conductivity that was previously identified with the Mott-Hubbard gap is actually associated with the excitation of a small polaron. The assignment is based on an excellent match between the experimental spectra and first-principles calculations for polaron excitation mechanisms

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

    Science.gov (United States)

    Tay, Jian Wei; Ledingham, Patrick M; Longdell, Jevon J

    2010-08-10

    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 étendue. The method also has the benefit that high sensitivity can be obtained with moderate absorption contrast for the spectral holes. PMID:20697433

  16. Rare-earth pnictides and chalcogenides from first-principles

    Science.gov (United States)

    Petit, L.; Szotek, Z.; Lüders, M.; Svane, A.

    2016-06-01

    This review tries to establish what is the current understanding of the rare-earth monopnictides and monochalcogenides from first principles. The rock salt structure is assumed for all the compounds in the calculations and wherever possible the electronic structure/properties of these compounds, as obtained from different ab initio methods, are compared and their relation to the experimental evidence is discussed. The established findings are summarised in a set of conclusions and provide outlook for future study and possible design of new materials.

  17. Thermochemical properties of rare earth complexes with salicylic acid

    International Nuclear Information System (INIS)

    Fourteen rare earth complexes with salicylic acid RE(HSal)3.nH2O (HSal = C7H5O3; RE = La-Sm, n = 2; RE = Eu-Lu, n = 1) were synthesized and characterized by elemental analysis, and their thermal decomposition mechanism were studied with TG-DTG technology. The constant-volume combustion energies of complexes, ΔcU, were determined by a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, ΔcHm0, and standard molar enthalpies of formation, ΔfHmo, were calculated

  18. Study about chemical and radiological toxicity of rare earths

    International Nuclear Information System (INIS)

    The maximum permissible concentration in workplace air for an admixture of rare earths is calculated to be 1.47 mg/m3 of air. This value takes into account the biological mean-life of those chemical elements in human body and acute toxicological data. A simplified mathematical models is done that describes the body content of this product as a time function, for cronic intoxication by air particulate inhalation. Under the radiological point of view the limit calculated for the air concentration is about 100 mg/m3, showing that the chemical toxity of these products is predominant. (Author)

  19. Synthesis of nanocrystalline rare earth oxides by glycothermal method

    International Nuclear Information System (INIS)

    The reaction of yttrium acetate hydrate in 1,2-propanediol at 300 deg. C yielded a product containing acetate groups and glycol moieties. From this product, Y2O3 was directly crystallized at 400 deg. C without the formation of a carbonate oxide phase. The thus-obtained Y2O3 samples had a small crystallite size (2.2 nm) and significantly large surface area (280 m2/g). Other nanocrystalline rare earth (Gd-Yb) oxides were also obtained by this method

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

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    By Lihua ZHANG; Mingsheng YANG; Xiaofang LIU

    2011-01-01

    @@ 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. Iron - rare earths separation through double salt, oxalate precipitation - a combined process

    International Nuclear Information System (INIS)

    Sodium diuranate (SDU) obtained at Heavy Water Board (HWB) during uranium recovery from phosphoric acid by D2EHPA-TBP process contains significant amount of iron and valuable rare earths particularly heavier rare earths such as Y, Er, Yb, Dy etc. Separation of valuable rare earths and iron from SDU is essential to get nuclear grade pure uranium. In the present work efforts have been made to devise a solvent extraction cum precipitation process to separate uranium from rare earths and iron followed by selective separation of rare earths from iron by precipitation route

  3. Extraction of trivalent rare-earth metal nitrates by solutions of tributyl phosphate and diisooctylmethylphosphonate in kerosene

    International Nuclear Information System (INIS)

    Isotherms of extraction of trivalent rare-earth metal nitrates in the series lanthanum-lutetium, yttrium by 0.5-2.5 M solutions of tri-n-buty1 phosphate and diisooctyl methylphosphonate in kerosene at 298.15 K, pH 2 are presented. The influence of the ionic strength of aqueous phase and extractant concentration on the concentration extraction constants in the case of formation of metal(III) trisolvates in organic phase is given by equation

  4. Solvent extraction of rare earths from thiocyanate medium using N,N,N',N'-tetra-2-ethylhexyl diglycolamide

    International Nuclear Information System (INIS)

    TEHDGA (N,N,N',N'-tetra-2-ethylhexyl diglycolamide), a neutral extractant, has been explored for separation of Yttrium from other heavy rare earths (Er) from thiocyanate medium. Presence of 5%(v/v) isodecyl alcohol was found to be optimum to prevent third phase formation. Experimental variables such as TEHDGA concentration (0.05M-0.2M), thiocyanate concentration (0.01M-0.04M), aqueous pH, rare earth concentration (0.25g/L-5g/L), temperature (35℃-65℃), stripping reagents on extraction of rare earths were investigated. The extraction of rare earths increased with increase in TEHDGA concentration and the dependency of distribution ratio of rare earth on TEHDGA concentrations is shown. The slopes were analysed to be approximately 3 for all the rare earths. The effect of thiocyanate concentration on distribution ratio is depicted. Based on slope analysis technique, the extracted species was found to be RE(SCN)3.3TEHDGA. The distribution ratio values decreased, may possibly be due to decrease in free extractant concentration in the organic phase, from 8.4 to 0.1 for Y with increase in yttrium concentration in the range of 0.25g/L to 5g/L. The extraction of rare earth decreased with increase in temperature indicating exothermic in nature and the enthalpy change (ΔH) obtained for Y(III) was -14.27KJ/mol. Among stripping reagents studied, oxalic acid was efficient in quantitative stripping of rare earths from TEHDGA. The extraction efficiency for rare earths by TEHDGA increased with increase in atomic number: La< Ce< Pr< Nd< Sm< Y< Eu< Gd< Tb< Dy< Ho< Er< Tm< Lu irrespective of thiocyanate concentration. Separation factors between these metal ions were also evaluated. High separation factor of 6.4 for Er/Y pair at 0.03M thiocyanate has indicated the feasibility of using TEHDGA as extractant to separate Y from Er and other rare earths as an alternative for Aliquat 336-thiocyanate system developed in our laboratory

  5. Heavy rare earths, permanent magnets, and renewable energies: An imminent crisis

    International Nuclear Information System (INIS)

    This article sounds the alarm that a significant build-out of efficient lighting and renewable energy technologies may be endangered by shortages of rare earths and rare earth permanent magnets. At the moment, China is the predominant supplier of both and its recent rare earth industrial policies combined with its own growing demand for rare earths have caused widespread concern. To diversify supplies, new mining—outside of China—is needed. But what many observers of the “rare earth problem” overlook is that China also dominates in (1) the processing of rare earths, particularly the less abundant heavy rare earths, and (2) the supply chains for permanent magnets. Heavy rare earths and permanent magnets are critical for many renewable energy technologies, and it will require decades to develop new non-Chinese deposits, processing capacity, and supply chains. This article clarifies several misconceptions, evaluates frequently proposed solutions, and urges policy makers outside of China to undertake measures to avert a crisis, such as greater support for research and development and for the cultivation of intellectual capital. - Highlights: • Rare earths are needed for many efficient lighting and renewable energy technologies. • The industries for rare earths and permanent magnets are dominated by China. • China's reliability is compromised, necessitating non-Chinese mining and processing. • Recycling, substitution and reducing rare earth content are long-term solutions only. • Policy makers should support development of supply chains and intellectual capital

  6. Synthesis of rare earth sulfides and their UV-vis absorption spectra

    Institute of Scientific and Technical Information of China (English)

    YUAN Haibin; ZHANG Jianhui; YU Ruijin; SU Qiang

    2009-01-01

    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.

  7. Magnetic and Magnetoelectric Properties of Rare Earth Molybdates

    Directory of Open Access Journals (Sweden)

    B. K. Ponomarev

    2012-01-01

    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.

  8. Light Emission from Rare-Earth Doped Silicon Nanostructures

    Directory of Open Access Journals (Sweden)

    P. Mascher

    2008-05-01

    Full Text Available Rare earth (Tb or Ce-doped silicon oxides were deposited by electron cyclotron resonance plasma-enhanced chemical vapour deposition (ECR-PECVD. Silicon nanocrystals (Si-ncs were formed in the silicon-rich films during certain annealing processes. Photoluminescence (PL properties of the films were found to be highly dependent on the deposition parameters and annealing conditions. We propose that the presence of a novel sensitizer in the Tb-doped oxygen-rich films is responsible for the indirect excitation of the Tb emission, while in the Tb-doped silicon-rich films the Tb emission is excited by the Si-ncs through an exciton-mediated energy transfer. In the Ce-doped oxygen-rich films, an abrupt increase of the Ce emission intensity was observed after annealing at 1200∘C. This effect is tentatively attributed to the formation of Ce silicate. In the Ce-doped silicon-rich films, the Ce emission was absent at annealing temperatures lower than 1100∘C due to the strong absorption of Si-ncs. Optimal film compositions and annealing conditions for maximizing the PL intensities of the rare earths in the films have been determined. The light emissions from these films were very bright and can be easily observed even under room lighting conditions.

  9. The Magnetic Ordering of Heavy Rare Earth Metals

    Science.gov (United States)

    Nordström, Lars

    1998-03-01

    The electronic and magnetic structures of the rare earth metals with hcp structure (Gd--Tm) are calculated by a full-potential LAPW method, which allows for non-collinear magnetism within the local approximation to spin-density functional theory. The 4f electrons are taken as localized, but their spin moment constrained as to fulfil Russel-Saunders coupling, polarizes the itinerant valence electrons. It is found that there are two competing magnetic structures; the ferromagnetic state, which dominates for the left-most elements (Gd and Tb), and a planar helical wave, which is found to have lowest energy for the last elements Er and Tm. In Ho the competition between the two leads to a compromise --- a helical cone. This trend is in accordance with the experimental situation. The mechanism behind the stabilization of the helical wave is confirmed to be an opening of a partial gap at the so-called ``webbing'' of the Fermi surface. This feature is found to exhibit nesting, a fact which is known both from earlier non-spin-polarized calculations and de Haas-van Alphen measurements. In contrast to prevailing models and earlier more primitive calculations, this nesting is found to exist for all elements, i.e. even for gadolinium. Instead, the magnitude of the spin splitting of the valence electrons due to the magnetic 4f states, is found to be an important quantity which has been missed out in the standard models for the magnetic structure of the rare earths.

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

    CERN Document Server

    Gajum, N R

    2001-01-01

    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...

  11. High purity samarium oxide from mixed rare earth carbonates

    International Nuclear Information System (INIS)

    A simple and economical chemical process for the production of highly pure samarium oxides is discussed. The raw material, which was used in the form of rare earth carbonates was produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography was performed using a strong cationic resin that is typically employed in water treatment processes to fractionate rare earth elements (REE) without the use of retention ions. Under these conditions, 99.9% pure Sm2O3 was eluted using the ammonium salt of ethylenediaminetetraacetic acid (EDTA) at a controlled pH. The EDTA-samarium complex was separated from EDTA and then precipitated as oxalate and fired to samarium oxide. Molecular absorption spectrophotometry was used to monitor the samarium content during the proposed process, and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the samarium oxide. Typical samarium oxide obtained from the proposed procedure contained the following contaminants in micrograms per gram: Sc (20.90); Y (11.80); La (8.4); Ce (4.3); Pr (2.5); Nd (5.1); Eu (94); Gd (114); Tb (3.6); Dy (2.5), Ho (2.3); Er (3.0); Tm (2.3); Yb (38,2); Lu (25.6). The high-purity samarium oxides produced in the present study can be used as an alternative to imported products in research and development applications. (author)

  12. Determination of free boron in rare earth hexaborides

    International Nuclear Information System (INIS)

    The method of N.I. Timofeeva et al. (1968) for the determination of free B in rare earth hexaborides was modified by replacing the 1:10 HNO3 by nonoxidizing 2:1 or 3:1 H2SO4 to dissolve the hexaborides and leave free B in the residue. A sample of 0.5-1.0 g rare earth hexaboride was heated in 50-80 ml 3:1 H2SO4 at 2100 for 2 hr, and the cool solutions was diluted. The residue containing free B and B4C was filtered, rinsed, and heated in dilute HNO3 at mild temperature for 15-20 min. The filtrate was separated from insoluble B4C, neutralized with 10% NaOH, and H3BO3 was titrated with NaOH in the presence of inverted sugar vs. phenophthalein. The free B content was underestimated by less than or equal to 4.3% in nearly all cases. The proposed technique is applicalbe to hexaborides of La, Y, Ce, Pr, Nd, Sm, Gd, and Eu

  13. Adsorption of rare earths with crown ether adsorbents

    International Nuclear Information System (INIS)

    Crown ether - phosphotungstic acid (PW) and crown ether -phosphomolybdic acid (PMo) precipitates, and also the granular entrapped crown ether - PMo (or PW) in polyacrylamide, were prepared and applied as adsorbents for rare earth metal ions. Adsorbents containing 15-crown-5, such as 15-crown-5 - PMo, were better adsorbents than the other crown ether precipitates. The adsorption capacity of 15-crown-5 - PMo for Eu3+ was determined and corresponded to about 0.166 mmol of Eu3+ per gram of the absorbent. The effects of pH and metal ion concentration on adsorption were also investigated. Crown ether - PMo (or PW) precipitates underwent hydrolysis at pH >= 1, but the granular entrapped crown ether - PMo (or PW) - polyacrylamide adsorbents were not hydrolysed at pH >= 1. The adsorption of individual rare earth ions with 15-crown-5 - PMo - polyacrylamide showed that Tb3+, Nd3+, Eu3+ and Gd3+ were readily adsorbed, but adsorption was difficult for Ce4+, Sm3+ and Dy3+. (author)

  14. Assessing rare earth elements in quartz rich geological samples.

    Science.gov (United States)

    Santoro, A; Thoss, V; Guevara, S Ribeiro; Urgast, D; Raab, A; Mastrolitti, S; Feldmann, J

    2016-01-01

    Sodium peroxide (Na2O2) fusion coupled to Inductively Coupled Plasma Tandem Mass Spectrometry (ICP-MS/MS) measurements was used to rapidly screen quartz-rich geological samples for rare earth element (REE) content. The method accuracy was checked with a geological reference material and Instrumental Neutron Activation Analysis (INAA) measurements. The used mass-mode combinations presented accurate results (only exception being (157)Gd in He gas mode) with recovery of the geological reference material QLO-1 between 80% and 98% (lower values for Lu, Nd and Sm) and in general comparable to INAA measurements. Low limits of detection for all elements were achieved, generally below 10 pg g(-1), as well as measurement repeatability below 15%. Overall, the Na2O2/ICP-MS/MS method proved to be a suitable lab-based method to quickly and accurately screen rock samples originating from quartz-rich geological areas for rare earth element content; particularly useful if checking commercial viability. PMID:26595776

  15. High purity samarium oxide from mixed rare earth carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Carlos A. da S.; Seneda, Jose A.; Vasconcellos, Mari E. de, E-mail: cqueiroz@ipen.br, E-mail: jaseneda@ipen.br, E-mail: mstela@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Pedreira Filho, Walter dos R., E-mail: walter.pedreira@fundacentro.gov.br [Fundaco Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho (FUNDACENTRO), Sao Paulo, SP (Brazil)

    2013-07-01

    A simple and economical chemical process for the production of highly pure samarium oxides is discussed. The raw material, which was used in the form of rare earth carbonates was produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography was performed using a strong cationic resin that is typically employed in water treatment processes to fractionate rare earth elements (REE) without the use of retention ions. Under these conditions, 99.9% pure Sm{sub 2}O{sub 3} was eluted using the ammonium salt of ethylenediaminetetraacetic acid (EDTA) at a controlled pH. The EDTA-samarium complex was separated from EDTA and then precipitated as oxalate and fired to samarium oxide. Molecular absorption spectrophotometry was used to monitor the samarium content during the proposed process, and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the samarium oxide. Typical samarium oxide obtained from the proposed procedure contained the following contaminants in micrograms per gram: Sc (20.90); Y (11.80); La (8.4); Ce (4.3); Pr (2.5); Nd (5.1); Eu (94); Gd (114); Tb (3.6); Dy (2.5), Ho (2.3); Er (3.0); Tm (2.3); Yb (38,2); Lu (25.6). The high-purity samarium oxides produced in the present study can be used as an alternative to imported products in research and development applications. (author)

  16. Samarium-cobalt type rare earth permanent magnets

    International Nuclear Information System (INIS)

    Permanent magnets are one of the oldest and largest applications of magnetic materials and form an integral part of our modern industrial society. They belong to a special class of functional materials and are characterized for remanence (flux output from the magnet), coercivity (resistance to demagnetization) and energy product (material energy density) from the second quadrant of the magnetic hysteresis loop. The reliability, stability, size, weight, cost and performance of many electro-technical devices depend mainly on the properties of permanent magnets used in them. There are three important families of permanent magnets viz., Ferrites, Alnicos and Rare Earth Permanent Magnets (REPMs) with energy product values ranging from 3 to 50 MGOe and among the front ranking high performance REPMs, SmCo5, Sm2Co17 type and NdFeB alloys are technologically the most important materials. They are used in a wide range of applications ranging from consumer products to very specialized areas of tele-communications, microelectronics, defence, space, avionics etc. While NdFeB has the highest energy product, Sm-Co based magnets are preferred for most critical applications where temperature stability of magnetic properties is essential because of their significantly higher Curie temperatures. In this presentation some of the key challenges associated with these Sm-Co based rare earth permanent magnets will be highlighted. (author)

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

    International Nuclear Information System (INIS)

    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−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 CoFe2O4 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

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

    DEFF Research Database (Denmark)

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

    1978-01-01

    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 ...... to vary only slightly with temperature. They are further assigned to definite R's in the unit cell, which cannot be done from macroscopic magnetic measurements.......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...

  19. Rare Earth Metal/semiconductor Interfaces and Compounds

    Science.gov (United States)

    Nogami, Jun

    Interfaces formed at room temperature by incremental deposition of rare earth metals onto semiconductor substrates have been studied with surface sensitive soft X-ray photoelectron spectroscopy. The trends in core level lineshape and intensity with increasing metal coverage have been used to deduce an outline of the evolution and the final morphology of the interfacial region on a microscopic scale. Measurements were taken for Ytterbium (Yb) on Silicon (Si), Germanium, and Gallium Arsenide, and for Gadolinium (Gd) and Europium (Eu) on Silicon. The Yb/Si interface work was supported by comparable measurements of bulk Yb silicide samples of known composition and crystal structure. In a general sense, the behavior of all the systems studied is similar. At very low metal coverages, the metal atoms chemisorb and are weakly bonded to the substrate. The 4f core levels indicate that the metal-metal atom coordination is relatively low at this stage. The interaction with the substrate strengthens with increasing coverage, culminating in the formation of a strongly reacted phase at between 1 and 3 monolayers (ML). The strong reaction is limited to a narrow region at room temperature. At less than 10 ML coverage, the surface of the sample is almost indistinguishable from the pure metal. Details of the behavior such as the reactivity at low coverage, the compounds formed at the interface, the morphology at the surface at intermediate coverages, the final interfacial width, and the amount of substrate atom outdiffusion and surface segregation can all vary from system to system. It is in explaining the causes of some of these differences that insight about what governs the behavior of all of these rare earth metal/semiconductor systems has been obtained. The divalent metals (Yb, Eu) are significantly less reactive than trivalent Gd at sub-monolayer coverages. For the divalent metals the formation of a metal-rich phase is strongly favored in the reaction at the interface, whereas

  20. Rare earth minerals and resources in the world

    Energy Technology Data Exchange (ETDEWEB)

    Kanazawa, Yasuo [Human Resource Department, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba 305-8568 (Japan)]. E-mail: y.kanazawa@aist.go.jp; 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)

    2006-02-09

    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

  1. Thermochemical study of rare earth and nitrogen incorporation in glasses

    Science.gov (United States)

    Zhang, Yahong

    Rare earth containing aluminosilicate, borosilicate, aluminate and nitrogen containing aluminosilicate glasses are technically important materials. They have extraordinary physical and chemical properties such as high glass transition temperature, very low electrical conductivity, and excellent chemical stability. These unique properties lead to applications as coatings on metals and ceramics, optical fibers, semiconductors, and nuclear waste containment materials. In addition, such systems contain the most widely used additives for sintering of Si3N4, SiAlON and SiC ceramics for high temperature applications. Thermodynamic properties and the relations among energetics, structure and bonding are essential to controlling processing parameters to synthesize, at lower cost, materials having better properties. Earlier investigations mainly pertained to specific physical properties of rare-earth doped oxide and oxynitride glasses. Work on the thermodynamic stability and materials compatibility has been very sparse. High temperature solution calorimetry in molten oxide solvents is a powerful tool for the thermodynamic study of refractory materials. With implementation and improvement, this technique has been applied to the first measurement of enthalpies of formation of RE-Si-Al-O glasses, REAlO3 glasses, RE-Si-Al-O-N glasses, and Si3N 4 and Ge3N4 with high pressure spinel structure. The first successful synthesis of REAlO3 glasses has been achieved by containerless melting. Their large enthalpies of crystallization confirm that they are reluctant glass formers. For glasses along the 2REAlO3 -3SiO2 join, the strongly negative heats of mixing support the absence of miscibility gaps except possibly at very high silica content. Energetic evidence has been presented for incipient phase-ordered regions in Gd- or Hf-containing sodium alumino-borosilicate glasses for plutonium immobilization. Linear relations between enthalpies of formation of RESiAlON glasses from elements and

  2. Preparation and Characterization of Rare Earth Doped Fluoride Nanoparticles

    Directory of Open Access Journals (Sweden)

    Timothy A. DeVol

    2010-03-01

    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.

  3. Gaps and pseudogaps in perovskite rare earth nickelates

    Energy Technology Data Exchange (ETDEWEB)

    Allen, S. James; Ouellette, Daniel G.; Kally, James; Kozhanov, Alex [Department of Physics, University of California, Santa Barbara, California 93106 (United States); Hauser, Adam J.; Mikheev, Evgeny; Zhang, Jack Y.; Moreno, Nelson E.; Son, Junwoo; Stemmer, Susanne [Materials Department, University of California, Santa Barbara, California 93106 (United States); Balents, Leon [Department of Physics, University of California, Santa Barbara, California 93106 (United States); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States)

    2015-06-01

    We report on tunneling measurements that reveal the evolution of the quasiparticle state density in two rare earth perovskite nickelates, NdNiO{sub 3} and LaNiO{sub 3}, that are close to a bandwidth controlled metal to insulator transition. We measure the opening of a sharp gap of ∼30 meV in NdNiO{sub 3} in its insulating ground state. LaNiO{sub 3}, which remains a correlated metal at all practical temperatures, exhibits a pseudogap of the same order. The results point to both types of gaps arising from a common origin, namely, a quantum critical point associated with the T = 0 K metal-insulator transition. The results support theoretical models of the quantum phase transition in terms of spin and charge instabilities of an itinerant Fermi surface.

  4. Proposal for laser cooling of rare-earth ions

    Science.gov (United States)

    Lepers, Maxence; Hong, Ye; Wyart, Jean-François; Dulieu, Olivier

    2016-01-01

    The efficiency of laser cooling relies on the existence of an almost closed optical-transition cycle in the energy spectrum of the considered species. In this respect, rare-earth elements exhibit many transitions which are likely to induce noticeable leaks from the cooling cycle. In this work, to determine whether laser cooling of singly ionized erbium Er+ is feasible, we have performed accurate electronic-structure calculations of energies and spontaneous-emission Einstein coefficients of Er+, using a combination of ab initio and least-squares-fitting techniques. We identify five weak closed transitions suitable for laser cooling, the broadest of which is in the kilohertz range. For the strongest transitions, by simulating the cascade dynamics of spontaneous emission, we show that repumping is necessary, and we discuss possible repumping schemes. We expect our detailed study on Er+ to give good insight into the laser cooling of neighboring ions such as Dy+.

  5. Crystallization of mixed rare earth (didymium) molybdates in silica gel

    Indian Academy of Sciences (India)

    Sanjay Pandita; Ravender Tickoo; K K Bamzai; P N Kotru; Neera Sahni

    2001-10-01

    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.

  6. Preparing Process of Cerium Acetate and Rare Earth Acetate

    Institute of Scientific and Technical Information of China (English)

    Qiao Jun; Ma Ying; Xu Yanhui; Zhang Jun; Chang Shu; Hao Xianku

    2004-01-01

    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.

  7. Radioluminescence of rare-earth doped aluminum oxide

    Energy Technology Data Exchange (ETDEWEB)

    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: msantiag@exa.unicen.edu.ar [Universidade Federal de Pernambuco, Departamento de Energia Nuclear, Av. Prof. Luiz Freire 1000, Recife, PE 50740-540 (Brazil)

    2011-10-15

    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)

  8. Synthesis and characterization of hydrogel bonded with rare earth

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

    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.

  9. Rare earth element determination by HPLC method with postcolumn derivatization

    International Nuclear Information System (INIS)

    Standard rare earth element solutions were prepared from the oxides of the elements. HPLC was used for the element separation and determination. Three complex-forming agents were used for derivation. The best results were achieved when arsenazo III was used. With Chromazurol S at pH = 9.5, the results were significantly dependent on the agent age while chlorophosphonazo III showed significantly lower sensitivity. The optimum values were determined of pH, agent concentration, capillary length and flow rate. The suitability of the method developed was tested on standard materials. Accuracy of determination for the individual elements ranged within 1.6% (Nd) and 7.4% (Eu). The duration of analysis was 25 minutes for a sample containing all lanthanoids. (M.D.). 1 fig., 1 tab., 28 refs

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

    Indian Academy of Sciences (India)

    R Nirmala; A V Morozkin; S K Malik

    2015-06-01

    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.

  11. Rare earth doped gallium nitride layers for photonics applications

    Czech Academy of Sciences Publication Activity Database

    Prajzler, V.; Hüttel, I.; Špirková, L.; Oswald, Jiří; Peřina, Vratislav; Zavadil, Jiří; Hamáček, J.; Machovič, V.; Burian, Z.

    Bellingham : SPIE The International Society for Optical Engineering, 2006 - (Tománek, P.; Hrabovský, M.; Miler, M.; Senderáková, D.), p.618018.1-618018.6 ISBN 0-8194-6236-5. ISSN 0277-786X. - (Proceedings of SPIE. 6180). [Photonics Prague 2005. International Conference on Photonics, Devices and Systems /5./. Prague (CZ), 08.06.2005-11.06.2005] R&D Projects: GA ČR(CZ) GA104/03/0385; GA ČR(CZ) GA104/03/0387 Institutional research plan: CEZ:AV0Z2067918 Keywords : gallium compounds * rare earth compounds * photoluminescence Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  12. Holeburning in rare earth doped nanoparticles of MgS

    International Nuclear Information System (INIS)

    In this paper we report the optical holeburning in nanoparticles of Eu-doped in MgS. In the form of microparticles and thin films MgS:Eu is known to have very favorable characteristics for spectral holeburning-based memories. Nanoparticles of MgS:Eu have been produced by quench condensing the laser ablated vapors from a solid target. The pressure of the ambient gas in the chamber has been used to control the size of particles. Our experiments produced particles as small as 3 nm in diameter. Results are presented on holeburning characteristics of nanoparticles, especially, their thermal behavior. These results are discussed with reference to rare earth based high-density memories

  13. Holeburning in rare earth doped nanoparticles of MgS

    Energy Technology Data Exchange (ETDEWEB)

    Dardona, Sameh; Konjhodzic, Aras; Chhabria, Deepika; Salihoglu, Omer; Hasan, Zameer E-mail: zhasan@temple.edu

    2004-05-01

    In this paper we report the optical holeburning in nanoparticles of Eu-doped in MgS. In the form of microparticles and thin films MgS:Eu is known to have very favorable characteristics for spectral holeburning-based memories. Nanoparticles of MgS:Eu have been produced by quench condensing the laser ablated vapors from a solid target. The pressure of the ambient gas in the chamber has been used to control the size of particles. Our experiments produced particles as small as 3 nm in diameter. Results are presented on holeburning characteristics of nanoparticles, especially, their thermal behavior. These results are discussed with reference to rare earth based high-density memories.

  14. Supramolecular structures constructed from three novel rare earth metal complexes

    Indian Academy of Sciences (India)

    Huaze Dong; Xiaojun Feng; Xia Liu; BiN Zheng; Jianhong Bi; Yan Xue; Shaohua Gou; Yanping Wang

    2015-05-01

    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.

  15. Rare earth element patterns in biotite muscovite and tourmaline minerals

    International Nuclear Information System (INIS)

    Rare earth element (REE) concentrations in the minerals biotite and muscovite from the mica schist country rocks of the Etta pegmatite and tourmalines from the Bob Ingersoll pegmatite were measured by instrumental NAA and comprehensive NAA. The concentrations range from 10-4 g/g to 10-10 g/g. The REE patterns of biotite, muscovite and tourmaline reported herein are highly fractionated from light to heavy REE. The REE concentrations in biotite and muscovite are high and indigeneous. The pegmatite tourmalines contain low concentrations of REE. Variations in tourmaline REE patterns reflect the geochemical evolution of pegmatite melt/fluid system during crystallization. (author) 10 refs.; 4 figs.; 3 tables

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

    Institute of Scientific and Technical Information of China (English)

    Li Jinhua

    2004-01-01

    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.

  17. Growth features of rare-earth scandium garnets

    International Nuclear Information System (INIS)

    The growth features of rare-earth scandium garnets (RESG) are closely connected with peculiarities of the nature of scandium garnets. The speciality of RESG first of all consists in complex scandium isomorphism, which is connected with redistribution of Sc3+ on sublattices of the garnet structure. The scandium isomorphism in RESG considerably influences the crystal growth, since scandium garnets possess a wide range of homogeneity at rather flat liquids. The presence of chromium ions in RESG strongly increases the absorption capability of the medium and leads to the rise of interface instability during the growth. The principal differences between ScGa- and ScAl-garnets concerning crystallization features are considered. (author). 38 refs., 2 figs

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    long as the rhabdophane structure is preserved. The bound hydrate water is accommodated in the rhabdophane structure and is stable at temperatures of up to 650 oC. The thermal stability of the hydrate water and the phosphate structure are of significance for the proton conductivity. The LaPO4·0.6H2O......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 to...... the monazite structure upon dehydration. The thermal stability of the hydrate is studied and found to contain water of two types, physically adsorbed and structurally bound hydrate water. The adsorbed water is correlated to the specific surface area and can be reversibly recovered when dehydrated as...

  19. Calculation of magnetic circular dichroism of rare-earth elements

    International Nuclear Information System (INIS)

    We present atomic calculations for the magnetic circular dichroism (MCD) in the 4d→4f excitation region of Eu, Gd, Tb, Dy, and Ho metal. The spectral shapes at T=0 K for non-polarized, right and left circularly polarized light, and their difference spectra are given. The interference effect between the 4d→4f excitation followed by 4d-4f4f super-Coster-Kronig decay process and the 4f→εg direct excitation process, which is known as the Fano effect, is considered in the calculations. The result reproduces the overall features of recently measured experiments. It is essential to consider the Fano effect for the understanding of the heavy rare-earth 4d→4f absorption and their MCD. (author)

  20. Clean separation technologies of rare earth resources in China

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

    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.

  1. Coupled-channel optical model potential for rare earth nuclei

    CERN Document Server

    Herman, M; Palumbo, A; Dietrich, F S; Brown, D; Hoblit, S

    2013-01-01

    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...

  2. Electronic and structural properties of rare earth pnictides

    Directory of Open Access Journals (Sweden)

    Bhardwaj Ramakant

    2016-03-01

    Full Text Available In the present paper structural and electronic properties of rare earth pnictides have been presented. The present calculation has been performed using self-consistent tight binding linear muffin tin orbital (TB-LMTO method within the local density approximation (LDA. The studied compounds undergo a structural phase transition from NaCl-type structure to CsCl-type structure. The electronic band structure and density of states of the pnictides have been reported. The equilibrium lattice parameter a (Å, bulk modulus B (GPa, number of f-states at the Fermi level Nf (states/Ry cell and volume collapse of AmBi and CmBi have also been reported. The calculated equilibrium structural parameters are in good agreement with the available experimental results.

  3. Dynamic population gratings in rare-earth-doped optical fibres

    Energy Technology Data Exchange (ETDEWEB)

    Stepanov, Serguei [Optics Department, CICESE, km.107 carr. Tijuana-Ensenada, Ensenada, 22860, BC (Mexico)], E-mail: steps@cicese.mx

    2008-11-21

    Dynamic Bragg gratings can be recorded in rare-earth (e.g. Er, Yb) doped optical fibres by two counter-propagating mutually coherent laser waves via local saturation of the fibre optical absorption or gain (in optically pumped fibres). Typical recording cw light power needed for efficient grating formation is of sub-mW-mW scale which results in characteristic recording/erasure times of 10-0.1 ms. This review paper discusses fundamental aspects of the population grating formation, their basic properties, relating wave-mixing processes and also considers different applications of these dynamic gratings in single-frequency fibre lasers, tunable filters, optical fibre sensors and adaptive interferometry.

  4. A review of fractionations of rare earth elements in plants

    Institute of Scientific and Technical Information of China (English)

    LIANG Tao; DING Shiming; SONG Wenchong; CHONG Zhongyi; ZHANG Chaosheng; LI Haitao

    2008-01-01

    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.

  5. Structural and mechanical stability of rare-earth diborides

    Institute of Scientific and Technical Information of China (English)

    Haci Ozisik; Engin Deligoz; Kemal Colakoglu; Gokhan Surucu

    2013-01-01

    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.

  6. Solvent extraction of carbonate complexes of rare earths

    International Nuclear Information System (INIS)

    Extraction of rare earth elements of yttrium subgroup from KHCO3 solutions with solutions of primary alkylamines (C10-C14) in CCl4 with the addition of propanole is investigated using holmium and ytterbium as an example. Using the methods of IR, PRM spectroscopy and chemical analysis of the saturated organic phase associates composition is studied. The simplest extarcted compounds can be presented with the formulas: n-C3H7OH x (C12H25NH3)7 [OH(CO3)5] and n-C3H7OH x bH2O(C12H25NH3)5 [Yb(CO3)4 x (Csub(3)Hsub(7)OH)sub(x)]. In holmium associate carbonatogroup is coordinated mainly according to bidentate type and in ytterbium associate - according to monodentate type. Moleculas of propyl alcohol are included in the coordination sphere of ytterbium associate

  7. Studies on the extraction of rare earth complexes with 8-hydroxyquinoline

    International Nuclear Information System (INIS)

    The extraction of Y(III), La(III) and Nd(III) with 8-hydroxyquinoline (HOx) in chloroform from aqueous and water-methanol solutions have been studied. Y(III), Pr(III) and Nd(III) ions were found to be extracted from aqueous phase as the complexes LnOx3. It was stated that the addition of methanol (MeOH) to aqueous phase causes the synergistic effect. In the presence of MeOH Y(III), Pr(III) and Nd(III) under the given conditions are extracted as solvates LnOx3 · 2MeOH, whereas La(III) as self-adduct LaOx3 · HOx. The values of pH0.5, pH0.5*, suitable extraction equilibrium constants and two-phase stability constants for the complexes LnOx3 were determined. The separation factors of Y(III), Pr(III), Nd(III) for the individual rare earth elements were calculated. (author). 28 refs, 5 figs, 2 tabs

  8. Pressure-induced exotic states in rare earth hexaborides

    Science.gov (United States)

    Sun, Liling; Wu, Qi

    2016-08-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bulai, G., E-mail: georgiana.bulai@uaic.ro [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)

    2015-09-15

    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.

  10. Pressure-induced exotic states in rare earth hexaborides.

    Science.gov (United States)

    Sun, Liling; Wu, Qi

    2016-08-01

    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. PMID:27376406

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

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Mertig, I.

    1990-01-01

    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......f states. The calculated electron-phonon mass enhancement λ exhibits a pronounced variation through the series with a maximum value of 1.07 in Pr and a minimum of 0.3 in Ho. We analyze the experimental data from specific heat and de Haas–van Alphen measurements in light of the calculated electron...

  12. Study on recovering directly the commercial cerium oxide and total of residue rare earths from Dongpao bastnasite concentrate

    International Nuclear Information System (INIS)

    A technology for decomposition roasting and sequential leaching processes of Dong Pao bastnasite concentrate to recover directly commercial cerium oxide and total of residue rare earth elements from the leaching solution of the roasted product have been investigated. The bastnasite concentrate is initially roasted at temperature range of 600 - 650 degC and for time of 4 hrs in order to decompose and convert the hardly soluble carbonate forms of ore into easily soluble oxide. The roasted solid is then leached with sulfuric acid solution of 6N at 60 degC for 4 hrs to convert rare earths in oxide and fluoride form into rare earth sulfate. The recovery yield of rare earths of these stages is more than 95%. The attention has especially been paid on recovering directly the commercial cerium oxide and total of residue rare earth element from the above leaching solution. Complex ions of CeSO42+, Ce(SO4)2, Ce(SO4)32- and Ce(SO4)44- exist in aqueous solution of cerium (IV) sulfate. Based on the property, the method of ion - sieve with DOWEX cation resin column has been applied to estimating separation of the ceric complex anions from Ln(III). The survey showed that most of the ceric complex anions are separated from total of residue rare earths. The latter which are absorbed in the cation column are recovered by elution of HCl of 4N. The recovery yield of cerium can only be reached 20% but the purity of that is very high, can be reached 99.6%. About 5 kg of CeO2 of high grade and 5 kg of TREO of commercial specification have been produced. (author)

  13. Charge ordering in perovskite rare-earth titanate compounds

    International Nuclear Information System (INIS)

    Having a single electron in the 3d shell, the rare-earth (RE) titanates RETiO3 have attracted strong interest to study the complex interplay of charge, orbital and magnetic degrees of freedom. Substituting divalent earth-alkali for the RE, a metal-insulator transition is induced, which in case of Y1-xCaxTiO3 occurs only at rather high doping. We have studied the hole-doped system (Y,Er,Lu)1-xCaxTiO3 by various diffraction techniques, by resistivity and by magnetic susceptibility measurements. This system shows a complex phase diagram of structural distortions accompanied by a metal-insulator transition. We ascribe the complex behavior to the coexistence of an insulating monoclinic phase with a metallic low-temperature orthorhombic phase. Our neutron diffraction data show that charge ordering occurs in the monoclinic phase. Even away from half-doping, we find two distinct Ti sites in a checkerboard arrangement, with significantly different TiO6 coordination

  14. Magnetic properties of rare earth oxides with perovskite structure

    International Nuclear Information System (INIS)

    A perovskite composite oxide is represented by the general formula of ABO3. Cations at the B site characterize magnetic properties of the oxide. Many studies have been accumulated for transition metal elements at the B sites. In this report the studies of rare earth elements at the B sites are reviewed. In rare elements, tetravalent ions such as Ce4+, Pr4+ and Tb4+ can occupy the B sites with Ba and Sr ions at the A sites. Both the SrTbO3 and BaTbO3 have an orthorhombic structure and show the antiferromagnetic transition at about 33 K, which is originated from terbium ions coupled antiferromagnetically with the six neighboring terbium ions. A tetravalent praseodymium perovskite SrPrO3 shows no existence of the magnetic ordering down to 2.0 K. This is in contrast to the result of isomorphous BaPrO3, which shows an antiferromagnetic transition at 11.5 K. A double perovskite structure is represented by the formula A2LnMO6 (A=Ba, Sr, Ca; M=Ru, Ir). In a double perovskite compound Ba2PrRuO6, the Pr3+ and Ru5+ ions are arranged with regularity over the six-coordinate B sites. This compound transforms to an antiferromagnetic state below 117 K. Antiferromagnetic transition temperatures TN for isomorphous Sr and Ca show a clear tendency, TN(A=Ba)>TN(Sr)>TN(Ca), in the compounds with the same rare earth elements (Ln). The 6H-perovskite structure Ba3LnRu2O9 consists of linkages between LnO6 octahedra and Ru2O9 dimers made from face-shared RuO6 octahedra. The 6H-perovskite structure Ba3MRu2O9 (M=Sc, Y, La, Nd-Gd, Dy-Lu) have the valence state of Ba3M3+Ru24.5+O9. The magnetic susceptibilities show a broad maximum at 135-370 K. This magnetic behavior is ascribed to the antiferromagnetic coupling between two Ru ions in a Ru2O9 dimer and to the magnetic interaction between the Ru2O9 dimers. (author)

  15. Situation and Developing Trend of Rare-Earth Countercurrent Extraction Processes Control

    Institute of Scientific and Technical Information of China (English)

    柴天佑; 杨辉

    2004-01-01

    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.

  16. Possibility study of use rare earth deposit from Araxa, Minas Gerais State

    International Nuclear Information System (INIS)

    Prospecting work done by Instituto de Pesquisas Radioativas on the Barreiro area (Araxa, M.G.) has shown the existence of a rare earth deposit of about 700.000 ton, averaging 13,5 % rare earth oxide, mainly associated to the mineral monazite. In a first stage, the conventional mineral dressing methods were tried to treat the monazite. This was followed by a study of a chemical process for the production of rare earth compounds of commercial grade. The conventional methods of mineral dressing tested did not lead to satisfactory results. This was assumed to be due to insufficient liberation of the monazite. However, the application of the chemical process to the natural material, using concentrated sulfuric acid in the initial attack, allowed more than 90% rare earth extraction and a subsequent yield of commercial grade rare earth oxide, with over 75% rare earth recovery. (author)

  17. Immobilization of Radioactive Rare Earth oxide Waste by Solid Phase Sintering

    International Nuclear Information System (INIS)

    In the pyroprocessing of spent nuclear fuels, LiCl-KCl waste salt containing radioactive rare earth chlorides are generated. The radioactive rare earth oxides are recovered by co-oxidative precipitation of rare earth elements. The powder phase of rare earth oxide waste must be immobilized to produce a monolithic wasteform suitable for storage and ultimate disposal. The immobilization of these waste developed in this study involves a solid state sintering of the waste with host borosilicate glass and zinc titanate based ceramic matrix (ZIT). And the rare-earth monazite which synthesised by reaction of ammonium di-hydrogen phosphate with the rare earth oxides waste, were immobilized with the borosilicate glass. It is shown that the developed ZIT ceramic wasteform is highly resistant the leaching process, high density and thermal conductivity.

  18. Technology of production of high-level concentrate of rare earths from Kola apatite

    International Nuclear Information System (INIS)

    The procedure is described of separating rare earth elements from the Kola apatite which contains 0.7 to 1.0% oxides of rare earths. The separation takes place during the manufacture of combined fertilizer NPK-1. During the manufacture of the fertilizer the solution is neutralized with the precipitation of phosphates of rare earths. Increasing pH is accompanied by increased yield of the sum of rare earths. The yield is higher for lighter lanthanoids than for heavier lanthanoids. The phosphate concentrate is decomposed by nitric acid and rare earth elements are precipitated by oxalic acid. Following the annealing of the oxalate concentrate the obtained oxide concentrate will contain 92 to 95% oxides of rare earths. (E.S.)

  19. History and Present Situation and Developing Tendency of Rare Earth Applied in Agriculture

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@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.

  20. Purification of rare earths nitrate solution yielded from Bangka's monazite ore processing using solvent extraction method

    International Nuclear Information System (INIS)

    Monazite Bangka ore processing has several steps i.e. ore preparation, decomposition, dissolution, purification, and drying. The experiment has done on residue dissolution of base decomposition of Bangka's monazite decomposition using nitric acid to produce rare earths nitrate with the solvent condition HNO3 14 N H2O2 20 cc/50 gram, time one hour, feed and solvent ratio = 1:1 (volume) and at room temperature. The experiment goal is to find optimal condition of rare earth nitrate purification from and Th using solvent extraction. The parameters are diluents feed (normal feed), ratio aqueous and organic (A/O), TBP/Kerosene content and extraction time. The results are the optimal extraction condition: feed extraction RE (NO3)3 7 N or none diluents, ratio A/O = 1:1, TBP / Kerosene content 40%, extraction time 5 minutes and at room temperature with U recovery = 93.13 %, h = 86.04 %, RE2O3 = 4.05 %, PO4 = can not be detected

  1. Group separation of rare earth substances utilizing supercritical fluid extraction technique

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Ki Pung; Joung, Seung Nam; Kim, Sun Hee; Jeon, Seong Ho; Choi, Eun Hyun [Sogang University, Seoul (Korea)

    1998-04-01

    The solubilities of TBP and DEHPA in supercritical CO{sub 2} were measured at various equilibrium temperatures(i.e., 313.15, 323.15, 333.15K) and pressures(i.e., 10, 15, 20, 25MPa). It is observed that both the solubilities of TBP and DEHPA are increasing wit increasing temperatures and pressures(ant, thus the density). In general TBP showed higher solubility than DEHPA in CO{sub 2}. were carried out for recovering rare earth elements from the aqueous acidic feed waste solutions. We found that the level of Nd extraction with such supercritically mixed solvent tends to decreasing with increasing HNO{sub 3} and tends to uniform with increasing temperature and pressures. Also, extraction of rare earth TPPO, and TOPO in supercritical CO{sub 2}. For example, the SFE of Nd by these supercritical CO{sub 2}-containing organic solvents showed that the case of TBPO was higher than that of any other organic solvent. (author). 46 refs., 36 figs., 12 tabs.

  2. Effect of rare earth ions on the properties of glycine phosphite single crystals

    Science.gov (United States)

    Senthilkumar, K.; Moorthy Babu, S.; Kumar, Binay; Bhagavannarayana, G.

    2013-01-01

    Optically transparent glycine phosphite (GPI) single crystals doped with rare earth metal ions (Ce, Nd and La) were grown from aqueous solution by employing the solvent evaporation and slow cooling methods. Co-ordination of dopants with GPI was confirmed by X-ray fluorescence spectroscopic analysis. Single crystal X-ray diffraction analysis was carried out to determine the lattice parameters and to analyze the structural morphology of GPI with dopants, which indicates that cell parameters of doped crystals were significantly varied with pure GPI. Crystalline perfection of doped GPI crystals was determined by high resolution X-ray diffraction analysis by means of full width at half maximum values. Influence of the dopants on the optical properties of the material was determined. Paraelectric to ferroelectric transition temperature (Tc) of doped GPI crystals were identified using differential scanning calorimetric measurements. Piezoelectric charge coefficient d33 was measured for pure and doped GPI crystals. Hysteresis (P-E) loop was traced for ferroelectric b-axis and (100) plane of pure and doped GPI crystals with different biasing field and ferroelectric parameters were calculated. Mechanical stability of crystals was determined by Vickers microhardness measurements; elastic stiffness constant 'C11' and yield strength 'σy' were calculated from hardness values. Mechanical and ferroelectric properties of doped crystals were improved with doping of rare earth metals.

  3. Preparation and photocatalytic activity of rare earth doped TiO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Stengl, Vaclav [Institute of Inorganic Chemistry v.v.i. AS CR, 250 68 Rez (Czech Republic)], E-mail: stengl@iic.cas.cz; Bakardjieva, Snejana; Murafa, Nataliya [Institute of Inorganic Chemistry v.v.i. AS CR, 250 68 Rez (Czech Republic)

    2009-03-15

    A one-step, a one-pot, no post-synthesis calcination and no sol-gel synthesis was used for preparation of rare earth doped visible-light sensitive titania. This method is easy transferable to industrial conditions, is ecologically friendly and make it possible to production of low-cost photocatalytic pigment. The products were characterized by all common techniques (X-ray diffraction (XRD), BET and porosity, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM), UV/VIS spectra). The photocatalytic activity of the prepared samples was assessed by the photocatalytic decomposition of Orange II dye in an aqueous slurry under irradiation of 254, 365 and 400 nm wavelength. The rare earth (La, Ce, Pr, Nd, Sm, Eu, Dy, Gd) for doped titania were used, the best photocatalytic properties in visible light have samples doped with Nd{sup 3+} ions (k = 0.0272 min{sup -1} for UV and 0.0143 min{sup -1} for visible light)

  4. Equilibrium studies on mixed ligand complexes of some tripositive rare earth ions

    International Nuclear Information System (INIS)

    Interaction of the rare earth ions, La3+, Ce3+, Pr3+, Nd3+, Sm3+ and Eu3+ with the pair of ligands 1-amino-2-naphthol-4-sulphonic acid (an, H2A) and o-aminophenol (ap, HB) have been studied in aqueous solution at 25 degC (μ=0.1 M KNO3/NaCl). Equilibrium constants of the reactions involving the formations of the mixed ligand species MAB, MA2B2-, MB2A- (M = metal ion) and the binary complexes containing up to three ligand molecules have been evaluated from the pH-metric data, and coordinating behaviour of the ligands in the formation of the mixed ligand complexes has been discussed. (author). 10 refs., 1 tab., 1 fig

  5. Interfacial assembly of sandwich mixed (Phthalocyaninato)(Porphyrinato) rare earth triple-decker complexes

    International Nuclear Information System (INIS)

    Interfacial assembly of sandwich mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes [(Pc)Eu(Pc)Eu(TPyP)] (1) and [(TPyP)Sm(Pc)Sm(TPyP)] (2) (Pc = phthalocyaninate, TPyP = meso-tetrakis(4-pyridyl)porphyrinate) has been comparatively studied at the air/pure water and the air/CdCl2 aqueous solution subphase interfaces. Surface pressure-area isotherms revealed the remarkable increase of limiting mean molecular area of the triple-deckers with the presence of Cd2+, suggesting the occurrence of in situ interfacial coordination. The formation of coordination bonds between the pyridyl groups of TPyP macrocycles in the triple-deckers and Cd2+ ions from the subphase was further supported by FT-IR spectroscopic data. Electronic absorption measurements showed the formation of J-aggregates of the triple-decker molecules in the interfacial assembled films.

  6. Equilibrium studies on interactions of rare earth ions with phytic acid

    International Nuclear Information System (INIS)

    The interaction between phytic acid and trivalent rare earth metal ions, viz., Ce3+, Pr3+, Nd3+, Sm3+, Gd3+, Tb3+, Dy3+ and HO3+ has been investigated potentiometrically at 25degC. The proton-ligand stability constants (pKYH) of phytic acid and the stability constants (logK) of metal complexes formed in aqueous medium (μ = 0.1 M NaClO4) have been evaluated. The results indicate that eight protons of phytic acid are highly acidic, two are weakly acidic and two very weakly acidic, titrable in the pH ranges 1.2-4.9, 5.0-8.15 and 8.3-11.0 respectively. The stability of each phytic acid-lanthanide ion complex decreases with an increase in pH and follows the usual trend through the series. (author). 11 refs., 2 tabs

  7. X-ray fluorescence analysis of high purity rare earth oxides for common trace rare earth impurities

    International Nuclear Information System (INIS)

    Methods for the determination of individual trace common rare earth (RE) elements have been developed for fifteen RE oxide matrices viz. La2O3 to Lu2O3 and Y2O3. In general, for each matrix, two or three neighbouring elements on both sides of the matrix element are determined. The minimum determination limit (MDL) achieved is 0.002% for most of the elements. Special efforts were made to use a small amount of sample (as low as 400 mg) for the analysis by the use of double layer pellet technique and critical thickness studies. Practical experiences with 15 RE matrices, most of which are investigated for the first time, are discussed. Details of selection of instrumental parameters and analysis lines, precision and accuracy and preparation of samples and synthetic standards are given. Theoretical minimum detection limit (TMDL) for each analyte element is calculated in all the 15 matrices. (author). 50 tabs., 2 figs

  8. Method development for determination and recovery of rare earth elements from industrial fly ash

    OpenAIRE

    Perämäki, Siiri

    2014-01-01

    Rare earth elements (REE) are important in numerous high technology applications and in addition their supply risk is high, which gives rise to studying new sources for rare earth elements. Rare earth element concentrations in industrial fly ash samples collected from Finnish power plants, using a mixture of peat and biomass as a fuel, have been determined. Two sample pre-treatment methods, ultrasound- and microwave-assisted acid digestions, have been applied to fly ash samples. Measurement c...

  9. Reduction Chemistry of Rare-Earth Metal Complexes: Toward New Reactivity and Properties

    OpenAIRE

    Huang, Wenliang

    2013-01-01

    Rare-earths are a group of metals with fascinating physical properties and intriguing chemical reactivity. Organometallic rare-earth chemistry is of particular interest because of the increasing number of their applications in industry and consumer goods as well as the importance of understanding their physical and chemical properties. Despite the dominance of the trivalent oxidation state, recently, low-valent organometallic rare-earth compounds were characterized and showed interesting reac...

  10. Rare Earth Export Quota in the Second Half of 2008 Promulgated

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ 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.

  11. Modeling Preparative Chromatographic Separation of Heavy Rare Earth Elements and Optimization of Thulium Purification

    OpenAIRE

    Max-Hansen, Mark; Knutson, Hans-Kristian; Jönsson, Christian; Degerman, Marcus; Nilsson, Bernt

    2015-01-01

    Rare Earth Elements are in growing demand globally. This paper presents a case study of applied mathematical modeling and multi objective optimization to optimize the separation of heavy Rare Earth Elements, Terbium-Lutetium, by means of preparative solid phase extraction chromatography, which means that an extraction ligand, HDEHP, is immobilized on a C18 silica phase, and nitric acid is used as an eluent. An ICP-MS was used for online detection of the Rare Earths. A methodology for calibrat...

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

    OpenAIRE

    Timothy Ault; Steven Krahn; Allen Croff

    2015-01-01

    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...

  13. The establishment of preferred values for a series of rare-earth samples

    International Nuclear Information System (INIS)

    The report correlates the analytical data supplied by twelve laboratories for five samples of rare-earth materials, giving the results, their statistical treatment, and brief descriptions of the analytical methods used. Preferred mean values are given for total rare-earth oxides, thorium oxide, and some of the individual rare-earth elements. Additional results for the major and minor elements in the carbonatite sample (NIM 18/69) are also included

  14. Metal sulfide and rare-earth phosphate nanostructures and methods of making same

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Stanislaus; Zhang, Fen

    2016-06-28

    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.

  15. The origin of increase of damping in transition metals with rare earth impurities

    OpenAIRE

    Hohlfeld, A. Rebei J.

    2006-01-01

    The damping due to rare earth impurities in transition metals is discussed in the low concentration limit. It is shown that the increase in damping is mainly due to the coupling of the orbital moments of the rare earth impurities and the conduction $p$-electrons. It is shown that an itinerant picture for the host transition ions is needed to reproduce the observed dependence of the damping on the total angular moment of the rare earths.

  16. Overall Performance of Rare Earth Industry this year willExperience Significant Shrinkage

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>Chen Yanhai,Director of the Department of Raw Materials,the Ministry of Industry and Information Technology,said at the Fifth Baotou Rare Earth Industry Forum held on August 8 that there still exists rampant illegal and rulebreaking mining and production of rare earth in China,which seriously affects the development of the entire rare earth industry,in the first half

  17. Solvent extraction of rare earth (3) nitrates by trialkylmethylammonium nitrate from multicomponent solutions

    International Nuclear Information System (INIS)

    The extraction of rare earth (3) [praseodymium-lutetium, yttrium (3)] nitrates 0.4-1.10 mol/dm3 by solution of trialkyl-methylammonium in kerosene was studied. It is found that di- and trisolvates of rare earth (3) nitrates is formed in organic phase, extraction constants are determined. Physicochemical and mathematical models descriptive of distribution of metal (3) nitrates in binary and multicomponent systems are given. Optimum field of concentrations of rare earth mixture in rare earths was established during use of solutions of trialkylmethyl-ammonium nitrate in diluent

  18. Plain radiography with a rare-earth screen: comparison with calcium tungstate screen

    International Nuclear Information System (INIS)

    Plain radiographic examinations were performed on 388 patients (adult and pediatric) using either a calcium tungstate or rare-earth screen. Radiographs were compared for overall image quality, mottle, contrast, density, and detail. The rare-earth screen produced radiographs with significantly more mottle than did the standard screen. This was the result of minor differences between the grading of optimal and good. A major advantage or rare-earth screens is a 50% or more reduction in radiation exposure. The results here show that rare-earth screens may be used in plain radiographic examinations without a clinically important decrease in image quality

  19. Extraction-chromatographic determination of rare earths in alloys on the base of aluminium, containing scandium

    International Nuclear Information System (INIS)

    Extraction-chromatographic behaviour of rare earths, scandium and aluminium has been studied in extraction systems of tributylphosphate - HNO3 and di-(2-ethylhexyl)-phosphoric acid - HCl with the aim to choose the conditions of their separation. The chemical yield of scandium and terbium determined by the method of labelled atoms was for scandium of 90+-3% and for terbium of 88+-2%. The yield of rare earths lighter than terbium was less than 80%. While analyzing alloys containing yttrium, terbium or heavier rare earths, tributylphosphate should be used as extragent, and in case of rare earths lighter than terbium di-(2-ethylhexyl)-phosphoric acid should be used

  20. Calculation of binary phase diagrams between the actinide elements, rare earth elements, and transition metal elements

    International Nuclear Information System (INIS)

    Attempts were made to apply the Kaufman method of calculating binary phase diagrams to the calculation of binary phase diagrams between the rare earths, actinides, and the refractory transition metals. Difficulties were encountered in applying the method to the rare earths and actinides, and modifications were necessary to provide accurate representation of known diagrams. To calculate the interaction parameters for rare earth-rare earth diagrams, it was necessary to use the atomic volumes for each of the phases: liquid, body-centered cubic, hexagonal close-packed, and face-centered cubic. Determination of the atomic volumes of each of these phases for each element is discussed in detail. In some cases, empirical means were necessary. Results are presented on the calculation of rare earth-rare earth, rare earth-actinide, and actinide-actinide diagrams. For rare earth-refractory transition metal diagrams and actinide-refractory transition metal diagrams, empirical means were required to develop values for the enthalpy of vaporization for rare earth elements and values for the constant (C) required when intermediate phases are present. Results of using the values determined for each element are presented

  1. Understanding the influence of nanoenvironment on luminescence of rare-earth ions

    Indian Academy of Sciences (India)

    Pushpal Ghosh; Amitava Patra

    2005-11-01

    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.

  2. Effects of rare earths on friction and wear characteristics of magnesium alloy AZ91D

    Institute of Scientific and Technical Information of China (English)

    祁庆琚; 刘勇兵; 杨晓红

    2003-01-01

    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.

  3. A study on the Deactivation of Usy Zeolites with Different Rare Earth Contents

    Directory of Open Access Journals (Sweden)

    Henriques C.A.

    1998-01-01

    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.

  4. Degradation of reactive, acid and basic textile dyes in the presence of ultrasound and rare earths [Lanthanum and Praseodymium].

    Science.gov (United States)

    Srivastava, Pankaj; Goyal, Shikha; Patnala, Prem Kishore

    2014-11-01

    Degradation of five textile dyes, namely Reactive Red 141 (RR 141), Reactive Blue 21 (RB 21), Acid Red 114 (AR 114), Acid Blue 113 (AB 113) and Basic Violet 16 (BV 16) in aqueous solution has been carried out with ultrasound (US) and in combination with rare earth ions (La(3+) and Pr(3+)). Kinetic analysis of the data showed a pseudo-first order degradation reaction for all the dyes. The rate constant (k), half life (t1/2) and the process efficiency (φ) for various processes in degradation of dyes under different experimental conditions have been calculated. The influence of concentrations of dyes (16-40mg/L), pH (5, 7 and 9) and rare earth ion concentration (4, 12 and 20mg/L) on the degradation of dyes have also been studied. The degradation percentage increased with increasing rare earth amount and decreased with increasing concentration of dyes. Both horn and bath type sonicators were used at 20kHz and 250W for degradation. The sonochemical degradation rate of dyes in the presence of rare earths was related to the type of chromophoric groups in the dye molecule. Degradation sequence of dyes was further examined through LCMS and Raman spectroscopic techniques, which confirmed the sonochemical degradation of dyes to non-toxic end products. PMID:24491599

  5. 75 FR 25293 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Rare Earth...

    Science.gov (United States)

    2010-05-07

    ... Antitrust Division Notice Pursuant to the National Cooperative Research and Production Act of 1993--Rare.... (``the Act''), the Rare Earth Technology Consortium (``RETC'') has filed written notifications... to the venture are: Rare Earth Industry and Tecimology Association, Greenwood Village, CO;...

  6. Fourier transformation IR spectroscopy of rare earth hydrides and manganates

    International Nuclear Information System (INIS)

    The publication describes IR optical investigations of rare earth hybrids and manganates. Both of these material systems have a pronounced interaction with light in the IR spectral region and are therefore well suited for Fourier transformation IR spectroscopy. Especially the spectra of the La1-xCaxMnO3 films contain many structures that derive both from the investigated film and the substrate. Quantitative information on the properties of the material system is obtained by separating the optical properties of LCMO from the substrate by means of adaptation using a multilayer formalism. The temperature dependence of the IR spectra was investigated down to the low-temperature range. Splitting and frequency shifts of the phonon modes were quantified, and the sensitive influence of the oxygen concentration of the samples on their optical properties was demonstrated. As representatives of the class of rare earth hybrids, various aspects of the material systems NdH2, EuH2 and YHx were investigated in thin film samples grown on substrates by means of molecular beam epitaxy. Detailed RHEED and Auger electron spectroscopy investigations provided information on the growth process, crystalline structure and chemical composition of the samples. By using a buffer layer between the rare earth metals and the palladium protective layer which is necessary with Nd and Eu, the minimum thickness of the Pd layer could be reduced about by half. The structural changes resulting from hydrogen loading are investigated by means of Raman measurements of the Nd hydride. The raman-active phonons that were observed for the first time by this method are strongly dependent on the crystal structure, i.e. the various phases are identified as a function of the hydrogen concentration. With the aid of the isotope effect, the origin of the phonons observed in the IR reflection and transmission spectra can be attributed to hydrogen oscillations. Evaluation of the spectra by multilayer formalism provides

  7. Combinatorial investigation of rare-earth free permanent magnets

    Science.gov (United States)

    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

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

    Science.gov (United States)

    Chemin, Marie-Charlotte

    2015-04-01

    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

  9. Short-life neutronodeficient isotopes of rare-earth elements

    International Nuclear Information System (INIS)

    In this work the following isotopes and isomers of the rare-earth elements were identified mostly for the first time and some verified: 157Tm(Tsub(1/2) = 3.6 min), 158Yb(Tsub(1/2) = 1.1 min), 159Yb(Tsub(1/2) = 1.75 min), 160Yb(Tsub(1/2) = 4.8 min), 148sup(m)Tb(Tsub(1/2) = 2.1 min), 149sup(m)Tb(Tsub(1/2) = 4.5 min), 150sup(m)Tb(Tsub(1/2) = 6.0 min) and 152Tb(Tsub(1/2) = 4.0 min). All of them were obtained in the spallation reactions on thin tantalum targets bombarded with a 660 MeV proton beam. The terbium isomers were also obtained in the heavy-ion reactions 141Pr(12C,xn) Tb and 139La(16O,xn)Tb. A method of fast extraction of rare-earth element isobars by direct separation from the tantalum targets was developed. The tantalum targets were placed in the ion source with surface ionization of the mass-separator. Semiconductor detectors were used for X-ray and γ-ray as well as α-particle spectra measurements. On the basis of experimental results, decay schemes of investigated isotopes (except 159Yb) were prepared. Some regularities in the α-decay energies were observed for isotones with N = 84 and N = 86. Two-quasiparticle states of the multiplets [π(hsub(11/2)) v (fsub(7/2))] in odd-odd Tb isotopes and [v(hsub(9/2)) v (fsub(7/2)) in even-even Gd isotopes were observed. Existence of these states indicates that the pure collective models are not sufficient to explain properties of nuclei in the region of N = 82 and Z = 64. Conclusions are presented on the method of fast isotope separation, techniques of measurements, methods of isotope (isomer) identification and their application in work with mass-separators on high-energy proton beams. (author)

  10. Superconductivity and magnetism in rare-earth nickel boronitrides

    International Nuclear Information System (INIS)

    Quaternary rare-earth nickel boronitrides R3Ni2B2N(3-x) are intermetallic compounds with a unique layered crystal structure where NiB layers (PbO-type sheets) alternate with LaN triple-layers (rock salt type sheets). They exhibit interesting physical properties such as superconductivity and rare earth magnetism and are, thus, candidates for studying the interplay of superconductivity and magnetism. In the scope of this thesis crystal-chemistry and electronic ground state properties of R3Ni2B2N(3-x) with R=La, Ce, Pr, and Nd were investigated. Powder X-ray diffraction studies confirmed all these compounds and their solid solutions to crystallize in the body centered tetragonal La3Ni2B2N3 structure type. The substitution of La by Ce, Pr or Nd in (La,R)3Ni2B2N(3-x) leads to a gradual suppression of superconductivity which is analyzed in terms of Abrikosov-Gorkov pair breaking effects. While the novel compound Nd3Ni2B2N(3-x) shows a ferrimagnetic ordering and a spin re-orientation transition to a nearly antiferromagnetic state, Pr3Ni2B2N(3-x) is found to exhibit no long range magnetic order. Temperature dependent physical properties characterize Ce3Ni2B2N(3-x) as an intermediate valence system with a cerium valence near 3.2. The electrical resistivity and thermoelectric power of Ce3Ni2B2N(3-x) are analyzed in terms of the degenerate Anderson lattice model. From X-ray and neutron powder diffraction studies on La3Ni2B2N(3-x) a finite width of formation with respect to the N-stoichiometry is observed. The normal and superconducting state properties of La3Ni2B2N(3-x) were investigated by means of transport, magnetic and calorimetric measurements. A remarkable correlation and a systematic reduction of the superconducting transition temperature Tc from about 14 K to 12 K as well as changes of normal state characteristics like the residual resistivity with an increasing density of N-vacancies is established. A strong pair-breaking effect caused by vacancies or other non

  11. Promising wastewater treatment using rare earth-doped nanoferrites

    Science.gov (United States)

    Ahmed, M. A.; Bishay, Samiha T.; Khafagy, Rasha M.; Saleh, N. M.

    2014-01-01

    Single-phases of the spinel nanoferrites Zn0.5Co0.5Al0.5R0.04Fe1.46O4; 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 Sm3+ and Ce3+ resulted in the formation of nanospheres with average diameter of 14 and 30 nm respectively. In addition to the granular nanospheres, doping with Pr3+ and La3+ 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 Ce3+ to Ce4+ 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 (μeff) decreased, while the Curie temperature (TC) 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.

  12. Promising wastewater treatment using rare earth-doped nanoferrites

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, M.A., E-mail: moala47@hotmail.com [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)

    2014-01-15

    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

  13. High pressure behaviour of heavy rare earth mono antimonides

    International Nuclear Information System (INIS)

    We have investigated theoretically the high-pressure structural phase transition and cohesive properties of two heavy rare earth mono antimonides (RESb; RE = Dy and Lu) by using two body interionic potential with necessary modifications to include the effect of Coulomb screening by the delocalized 4f electrons of the RE ion. The peculiar properties of these compounds have been interpreted in terms of the hybridization of f electrons with the conduction band and strong mixing of f states of RE ion with the p orbital of neighboring pnictogen ion. These compounds exhibit first order crystallographic phase transition from their NaCl (B1) phase to CsCl (B2) phase at 23.6 GPa and 25.4 GPa respectively. The bulk modulii of RESb compounds are obtained from the P-V curve fitted by the Birch equation of state. We also calculated the RE-RE distance as a function of pressure. Elastic properties of these compounds have also been studied and their second order elastic constants are calculated.

  14. Rare earth elements in some bottled waters of Serbia

    Directory of Open Access Journals (Sweden)

    Todorović Maja

    2013-01-01

    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.

  15. Interactions of rare earth elements with bacteria and organic ligands

    International Nuclear Information System (INIS)

    We investigated the interactions of rare earth elements (REEs) Eu(III) and/or Ce(III, IV) with the common soil bacterium Pseudomonas fluorescens and organic ligands, such as malic acid, citric acid, a siderophore (DFO), cellulose, chitin, and chitosan. Malic acid formed complexes with Eu(III), but degradation of malic acid was observed when the ratio of malic acid to Eu(III) was higher than 100. Citric acid formed a stoichiometric complex with Eu(III) that was not degraded by P. fluorescens. Adsorption of Eu(III) from the DFO complex occurred as a free ion dissociated from DFO and not as the Eu(III)-DFO complex. Cerium(III) was oxidized to Ce(IV) during complexation with DFO to form the Ce(IV)-DFO complex. Time-resolved laser-induced fluorescence spectroscopy (TRLFS) analysis showed that cellulose, chitin, and chitosan, respectively, formed a weak complex, an inner-spherical complex, and an outer-spherical complex with Eu(III). This method also demonstrated that the coordination environment of Eu(III) adsorbed on P. fluorescens possessed similar characteristics to that of chitin, and revealed that adsorption of Eu(III) on P. fluorescens was through a multidentate and predominantly inner-spherical coordination

  16. Attenuation of rare earth elements in a boreal estuary

    Science.gov (United States)

    Åström, Mats E.; Österholm, Peter; Gustafsson, Jon Petter; Nystrand, Miriam; Peltola, Pasi; Nordmyr, Linda; Boman, Anton

    2012-11-01

    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 extract metals from the settling material. Aluminium, Fe and REE transported by the acidic creek were extensively removed in the inner/central estuary where the acidic water was neutralised, whereas Mn was relatively persistent in solution and thus redistributed to particles and deposited further down the estuary. The REE removal was caused by several contemporary mechanisms: co-precipitation with oxyhydroxides (mainly Al but also Fe), complexation with flocculating humic substances and sorption to suspended particles. Down estuary the dissolved REE pool, remaining after removal, was fractionated: the Humic Model after revision and updating, predicted that the dissolved (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.

  17. Proposal for laser cooling of rare-earth ions

    Science.gov (United States)

    Dulieu, Olivier; Hong, Ye; Wyart, Jean-François; Lepers, Maxence

    2016-05-01

    The efficiency of laser cooling relies on the existence of an almost closed optical-transition cycle in the energy spectrum of the considered species. In this respect, rare-earth elements exhibit many transitions which are likely to induce noticeable leaks from the cooling cycle. In this work, to determine whether laser cooling of singly ionized erbium Er+ is feasible, we have performed accurate electronic-structure calculations of energies and spontaneous-emission Einstein coefficients of Er+, using a combination of ab initio and least-squares-fitting techniques. We identify five weak closed transitions suitable for laser cooling, the broadest of which is in the kilohertz range. For the strongest transitions, by simulating the cascade dynamics of spontaneous emission, we show that repumping is necessary, and we discuss possible repumping schemes.We expect our detailed study on Er+ to give good insight into the laser cooling of neighboring ions such as Dy+. Supported by ``Agence Nationale de la Recherche'' (ANR), under the project COPOMOL (Contract No. ANR-13-IS04-0004-01).

  18. Oil-refinery and automotive emissions of rare earth elements

    International Nuclear Information System (INIS)

    The concentration pattern of rare-earth elements (REEs) in emissions from oil refineries and newer-model automobiles shows a distortion from the crustal abundance pattern. The REEs arise from the zeolite cracking catalysts used in petroleum refining and emission-control substrates used in automobile catalytic converters, respectively. Ten petroleum cracking catalysts from four countries and 12 catalytic converters from five automobile manufacturers were characterized for their REE content. The cracking catalysts are highly enriched in light REEs, whereas the automobile catalysts are enriched primarily in Ce. Incorporation of zeolite catalysts into refined oil provides new atmospheric elemental signatures for tracing emissions from refineries and oil-fired power plants on a regional scale. Though both have enhanced La/REE ratios, emissions from these two sources can be distinguished by their La/V ratios. Although REE demand by the petroleum industry has dropped considerably in recent years, automobile catalytic converters containing REEs are expected to increase dramatically as more stringent emission regulations are adopted in Europe, Japan and the US

  19. Thermoemission properties of tungsten with additions of rare earth oxides

    International Nuclear Information System (INIS)

    Thermoemission properties of tungsten with addition of rare earth oxides are studied in the superhigh vacuum set with oil-free pumping system. Electronic work function eφ is determined by the method of total saturation current. Temperature dependences are obtained of the work function for three types of cathodes: W+La2O3; W+φ2O3 and W+Dy2O3. It is stated, that the first two types eφ decreases approximately from 4.2 to 3.3 eV and from 4.5 to 3.8 eV, respectively, after activation at proper temperatures. These cathodes are the most effective ones at the temperature of 1700 (W+La2O3) and 1900-2100 K (W+ φ4O3). The work function of cathodes with addition of dysprosium oxide did not practically vary (4.55-4.3 eV) within the whole studied temperature interval (1500-2100 K)

  20. Spin voltage generation across rare earth spin filter barriers

    Science.gov (United States)

    Miao, Guoxing; Chang, Joonyeon; Moodera, Jagadeesh

    2011-03-01

    When a metal is in close contact with a rare-earth based magnetic compound, strong exchange interaction exists between the localized 4f electrons and the free moving conduction electrons. One important consequence is that the spin degeneracy among the conduction electrons is lifted, showing up as an effective Zeeman splitting higher than tens of Tesla in low dimensional systems such as graphene and other 2DEG. We perform our work using a vertical transport geometry, which consists of double spin filtering barriers based on a ferromagnetic Eu chalcogenide - EuS. A thin Al metallic layer is sandwiched in the middle and its conduction electrons thus experience the strong spin splitting, which is subsequently detected via the spin filtering effect. A spontaneous spin dependent voltage appears across such a device, and its polarity is directly determined by the EuS/Al interface. The voltage level difference between the spin-parallel and -antiparallel configurations is as large as a few mV. Such spin splitting also induces a clear universal behavior in the observed TMR bias dependence. Such spin voltage effect offers a possibility of directly converting magnetic exchange energy into electrical power. This work is supported by NSF DMR 0504158, ONR N00014-06-1-0235, and KIST-MIT project funds.

  1. Synthesis, structure, and physical properties of new rare earth ferrocenoylacetonates.

    Science.gov (United States)

    Koroteev, Pavel S; Dobrokhotova, Zhanna V; Ilyukhin, Andrey B; Efimov, Nikolay N; Rouzières, Mathieu; Kiskin, Mikhail A; Clérac, Rodolphe; Novotortsev, Vladimir M

    2016-04-12

    New ferrocenoylacetonate complexes of several rare earth elements, [Ln(fca)3(bpy)]·MeC6H5 (Ln = Pr (), Eu (), Gd (), Tb (), Dy (), Ho (), Y (); bpy - 2,2'-bipyridine; Hfca - FcCOCH2COMe) as well as scandium ferrocenoylacetonate [Sc(fca)3]·0.5MeC6H5 (), were synthesized and characterized by single crystal X-ray diffraction analysis. In the crystal lattice of the isostructural complexes , two [Ln(fca)3(bpy)] molecules form a pair due to stacking interactions between the bpy ligands. The Ln(3+) ions are coordinated in a square antiprism geometry with a coordination number of 8. The Sc(3+) ions in complex are coordinated in an octahedral geometry. Thermolysis of complexes was studied under air and argon atmospheres; in the first case, it affords perovskites LnFeO3 as one of the products. Complexes display single-molecule magnet properties, and the effective relaxation barrier for the Dy complex , was found to be Δeff/kB = 241 K, which is one of the highest values obtained for a mononuclear β-diketonate lanthanide complex. PMID:26948276

  2. Rare earth elements occurrences in the Northern Territory

    International Nuclear Information System (INIS)

    A description of the rare earth elements (REE), their occurrence and main applications is given. Currently, Australia is the largest producer of monazite (the principal source of REE) accounting for 40% of the total world production. Nevertheless, in Australia, and particularly in the Northern Territory, past mineral exploration has not been specifically targeted at REE, therefore the current knowledge on REE occurrences is limited. Elevated levels have been however recorded in six geological terrains: the Pine Creek Geosyncline, Southern McArthur Basin-murphy Inlier, Davenport Province, Arunta Orogen, Birrindudu Basin and Musgrave Block. They are briefly described. While the REE occurrences are not of economic proportion, they do record elevated levels in stream sediments, rock chip and drillcore analysis. In the majority of cases, the occurrences relate to the regionally folded Early Proterozoic metasediments and granitoid intrusives. Data sheets designated to present brief, factual information on these deposits are microfilmed and included in the volume's back pocket. 41 refs., 5 tabs., 1 fig

  3. Pulsed field magnetization in rare-earth kagome systems

    International Nuclear Information System (INIS)

    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. (paper)

  4. Rare-earth-activated wide bandgap materials for scintillators

    International Nuclear Information System (INIS)

    Open f-shell rare-earth (RE) ions in wide bandgap host materials are usually characterized by closely spaced electronic levels due to various electron configurations and charge states. These levels provide convenient luminescent transitions that can be excited by efficient recombination of charge carriers generated in the host material by ionizing radiation. Therefore, it is the area of ionizing radiation detectors, where search for new, fast and efficient scintillator materials for high-energy physics and nuclear medicine, has yielded much of the recent advances in the understanding of radioluminescence and scintillation mechanism in some solid state, UV and VUV luminescent, RE-activated materials. In this paper we shall present selected results of basic experiments such as radioluminescence, VUV spectroscopy, time profiles and thermoluminescence, on barium fluoride (activated with Ce, Pr, Nd, Tb) and two aluminum perovskites, YAlO3 and LuAlO3, activated with Ce. We shall demonstrate that these results point to consecutive carrier capture and recombination at RE ions as the basic mechanism of radioluminescence and scintillation in these materials, despite the strong self-trapping and poor charge transport properties. Consequently, various electron and/or hole traps that intercept and retain for some time the recombining charge carriers play an active role influencing both the scintillation light yield and time profiles of scintillation pulses in these and many other wide bandgap RE-activated luminescent materials

  5. Material and Energy Requirement for Rare Earth Production

    Science.gov (United States)

    Talens Peiró, Laura; Villalba Méndez, Gara

    2013-10-01

    The use of rare earth metals (REMs) for new applications in renewable and communication technologies has increased concern about future supply as well as environmental burdens associated with the extraction, use, and disposal (losses) of these metals. Although there are several reports describing and quantifying the production and use of REM, there is still a lack of quantitative data about the material and energy requirements for their extraction and refining. Such information remains difficult to acquire as China is still supplying over 95% of the world REM supply. This article attempts to estimate the material and energy requirements for the production of REM based on the theoretical chemical reactions and thermodynamics. The results show the material and energy requirement varies greatly depending on the type of mineral ore, production facility, and beneficiation process selected. They also show that the greatest loss occurs during mining (25-50%) and beneficiation (10-30%) of RE minerals. We hope that the material and energy balances presented in this article will be of use in life cycle analysis, resource accounting, and other industrial ecology tools used to quantify the environmental consequences of meeting REM demand for new technology products.

  6. Magnetization of rare earth kagome systems in pulsed fields

    Science.gov (United States)

    Hoch, Michael; Mun, Eun; Harrison, Neil; Zhou, Haidong

    2014-03-01

    The rare earth kagome systems R3 Ga5 SiO14 (R = Nd or Pr) exhibit cooperative paramagnetism at low temperatures. Evidence for correlated spin clusters in these weakly frustrated systems has previously been obtained in neutron scattering experiments. The present pulsed field (0 - 60 T) low temperature magnetization measurements on single crystals of Nd3 Ga5 SiO14 (NGS) and Pr3 Ga5 SiO14 (PGS) have revealed striking differences in the magnetic responses of these two materials. At 1.6 K NGS shows a low field plateau, saturation of the magnetization for μ0 H > 10 T and significant hysteresis while the PGS magnetization does not saturate in fields up to 60 T and shows no hysteresis or plateaus. While Nd3+ (J = 9/2) is a Kramers ion Pr3+ (J = 4) is not. The exchange couplings J ~ 1 K are similar for PGS and NGS but the crystal field splittings and anisotropies are quite different. The marked contrast in the behavior of the two kagome systems is attributed to differences in the spin cluster structures and dynamics. The pulsed field approach has great potential for investigating kagome cluster dynamics at low temperatures.

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

    Science.gov (United States)

    Bulai, G.; Diamandescu, L.; Dumitru, I.; Gurlui, S.; Feder, M.; Caltun, O. F.

    2015-09-01

    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-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 CoFe2O4 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.

  8. Pulsed field magnetization in rare-earth kagome systems

    Science.gov (United States)

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

    2016-02-01

    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. Oxidation Effects in Rare Earth Doped Topological Insulator Thin Films.

    Science.gov (United States)

    Figueroa, A I; van der Laan, G; Harrison, S E; Cibin, G; Hesjedal, T

    2016-01-01

    The breaking of time-reversal symmetry (TRS) in topological insulators is a prerequisite for unlocking their exotic properties and for observing the quantum anomalous Hall effect (QAHE). The incorporation of dopants which exhibit magnetic long-range order is the most promising approach for TRS-breaking. REBiTe3, wherein 50% of the Bi is substitutionally replaced by a RE atom (RE = Gd, Dy, and Ho), is a predicted QAHE system. Despite the low solubility of REs in bulk crystals of a few %, highly doped thin films have been demonstrated, which are free of secondary phases and of high crystalline quality. Here we study the effects of exposure to atmosphere of rare earth-doped Bi2(Se, Te)3 thin films using x-ray absorption spectroscopy. We demonstrate that these RE dopants are all trivalent and effectively substitute for Bi(3+) in the Bi2(Se, Te)3 matrix. We find an unexpected high degree of sample oxidation for the most highly doped samples, which is not restricted to the surface of the films. In the low-doping limit, the RE-doped films mostly show surface oxidation, which can be prevented by surface passivation, encapsulation, or in-situ cleaving to recover the topological surface state. PMID:26956771

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

    Science.gov (United States)

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

    2013-06-14

    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. PMID:23518599

  11. A Rare Earth High-iron Aluminum Alloy Cable Company to Settle in Chongqing

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>On September 14,the reporter learnt from the Seminar on Application of New Rare Earth High-iron Aluminum Alloy Cable Technologies for Energy Conservation and Environmental Protection held by Chongqing Electric Industry Association that a rare earth high-iron aluminum alloy cable company with

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

    Institute of Scientific and Technical Information of China (English)

    Xu Yue; Lu Liguo; Bai Jing

    2007-01-01

    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.

  13. Giant optical gain in rare-earth-ion-doped thin films and waveguides

    NARCIS (Netherlands)

    Geskus, D.; Aravazhi, S.; Garcia Blanco, S.M.; Pollnau, M.

    2011-01-01

    In a rare-earth-ion-doped double tungstate channel waveguide amplifier, we demonstrate an ultra-high modal gain of 950 dB/cm, two order of magnitude higher than in other rare-earth-ion-doped materials and comparable to modal gain in semiconductors.

  14. Hydrothermal method of synthesis of rare-earth tantalates and niobates

    Science.gov (United States)

    Nyman, May D; Rohwer, Lauren E.S.; Martin, James E

    2012-10-16

    A hydrothermal method of synthesis of a family of rare-earth Group 5 oxides, where the Group 5 oxide is a niobate or tantalate. The rare-earth Group 5 oxides can be doped with suitable emitter ions to form nanophosphors.

  15. CATALYTIC ACTIVITIES OF RARE-EARTH CALIXARENE COMPLEXES IN POLYMER SYNTHESES

    Institute of Scientific and Technical Information of China (English)

    Zhi-quan Shen

    2005-01-01

    The studies of our group on the catalytic activities of rare earth calixarene complexes in polymer syntheses are reviewed. Rare earth calixarene complexes are effect catalysts for the polymerizations of butadiene, isoprene, ethylene,styrene, propylene oxide, styrene oxide, trimethylene carbonate and 2,2-dimethyl-trimethylene carbonate.

  16. Synthesis, structure peculiarities and electric conductivity of alkali metal-rare earth silicates (germanates)

    International Nuclear Information System (INIS)

    The process of obtaining of rare earth-alkali metal silicates (germanates) is studied. The analysis of possibilities of structural disordering of alkaline cations in these structures is given. The interaction of the structure of different by the composition alkali alkali metal - rare earth silicates with electric conductivity values is shown

  17. Neural Networks Based Component Content Soft-Sensor in Countercurrent Rare-Earth Extraction

    Institute of Scientific and Technical Information of China (English)

    杨辉; 谭明皓; 柴天佑

    2003-01-01

    The equilibrium model for multicomponent rare earth extraction is developed using neural networks, which combined with the material balance model could give online prediction of component content in countercurrent rare earth extraction production. Simulation experiments with industrial operation data prove the effect iveness of the hybrid soft- sensor.

  18. Coated air-stable cobalt--rare earth alloy particles and method

    International Nuclear Information System (INIS)

    A process is described for producing novel air-stable coated particles of a magnetic transition metal-rare earth alloys. An organometallic compound which decomposes at a temperature below 5000C is heated to produce a metal vapor which is contacted with particles of a transition metal-rare earth alloy to deposit a metal coating on the particles. (U.S.)

  19. 40 CFR 421.270 - Applicability: Description of the primary rare earth metals subcategory.

    Science.gov (United States)

    2010-07-01

    ... primary rare earth metals subcategory. 421.270 Section 421.270 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Primary Rare Earth Metals Subcategory § 421.270 Applicability: Description of the primary...

  20. Selective Extraction of Rare Earth Elements from Permanent Magnet Scraps with Membrane Solvent Extraction.

    Science.gov (United States)

    Kim, Daejin; Powell, Lawrence E; Delmau, Lætitia H; Peterson, Eric S; Herchenroeder, Jim; Bhave, Ramesh R

    2015-08-18

    The rare earth elements (REEs) such as neodymium, praseodymium, and dysprosium were successfully recovered from commercial NdFeB magnets and industrial scrap magnets via membrane assisted solvent extraction (MSX). A hollow fiber membrane system was evaluated to extract REEs in a single step with the feed and strip solutions circulating continuously through the MSX system. The effects of several experimental variables on REE extraction such as flow rate, concentration of REEs in the feed solution, membrane configuration, and composition of acids were investigated with the MSX system. A multimembrane module configuration with REEs dissolved in aqueous nitric acid solutions showed high selectivity for REE extraction with no coextraction of non-REEs, whereas the use of aqueous hydrochloric acid solution resulted in coextraction of non-REEs due to the formation of chloroanions of non-REEs. The REE oxides were recovered from the strip solution through precipitation, drying, and annealing steps. The resulting REE oxides were characterized with XRD, SEM-EDX, and ICP-OES, demonstrating that the membrane assisted solvent extraction is capable of selectively recovering pure REEs from the industrial scrap magnets. PMID:26107531

  1. Remediation of Rare Earth Element Pollutants by Sorption Process Using Organic Natural Sorbents

    Directory of Open Access Journals (Sweden)

    Monica Butnariu

    2015-09-01

    Full Text Available The effects of the sorption of environmental applications by various source materials of natural organic matter, i.e., bone powder, was examined. Sorption capacities and subsequent rare earth element retention characteristics of all metals tested were markedly increased by ionic task-specific. In this study, the abilities of three models’ isotherms widely were used for the equilibrium sorption data: Langmuir, Freundlich and Redlich-Peterson. For all studied metal ions the maximum adsorption capacity is close to those experimentally determined. The characteristic parameters for each isotherm and related coefficients of determination have been determined. The experimental data achieved excellent fits within the following isotherms in the order: Langmuir > Redlich-Peterson > Freundlich, based on their coefficient of determination values. The bone powder has developed higher adsorption performance in the removal process of Nd(III, Eu(III, La(III from aqueous solutions than in the case of the removal process of Cs(I, Sr(II and Tl(I from aqueous solutions. The described relationships provide direct experimental evidence that the sorption-desorption properties of bone powder are closely related to their degree of the type of the metal. The results suggest a potential for obtaining efficient and cost-effective engineered natural organic sorbents for environmental applications.

  2. Study on Mechanism of Formation of Volcanic Rock in North Altay by Using Rare Earths

    Institute of Scientific and Technical Information of China (English)

    袁峰; 周涛发; 岳书仓

    2003-01-01

    The characteristics of rare earth elements in the Devonian and Carboniferous volcanic rocks were studied in the north Altay. And the mechanism of formation of volcanic rocks were discussed by using the rare earth elements. The correlativity of rare earth elements and major elements shows that the fractional crystallization is undistinguishable during the formation of Devonian and Carboniferous volcanic rocks, and the mechanism of formation of volcanic rocks may be the partial melting. The further study of the relationship of manifold rare earth elements shows that the mechanism of formation of Devonian and Carboniferous volcanic rocks in the north Altay is the partial melting. And the result also shows that the rare earth elements in the Devonian and Carboniferous volcanic rocks inherited the characteristics of those in its source materiels.

  3. Electronic and magnetic coupling between rare-earth adatoms and the Fe(001) surface

    International Nuclear Information System (INIS)

    The spin-dependent electronic structure of monolayer coverages of rare-earth metals on Fe(001) has been studied by spin-resolved photoelectron spectroscopy with synchrotron radiation. The highly spin-polarized photoemission from the localized 4f levels of Gd, Tb, and Dy on Fe(001) reveals the antiparallel coupling between these heavy rare earths and the Fe spin moment. Exchange-split final-state multiplet terms of the 4f spectra of the heavy rare earths are explicitly distinguished by direct observation of opposite polarization. For 1 monolayer of the light rare-earth Nd on Fe(001) the rare-earth magnetic moment couples parallel to the Fe magnetic moment

  4. Contribution to the study of rare earth separation by ion exchange, using ammonium lactate

    International Nuclear Information System (INIS)

    Using the technique of chromatography on a column of Dowex 50 resin, heated to 87 deg. C, we have studied the separation of rare earths (from holmium to praseodymium) which may be produced with the cyclotron by heavy ions, α or protons. From an ammonium lactate solution M at pH 5, separations are carried out by varying the dilution as a function of the quantity of the target rare earth and of its position during elution. When weighable quantities of the rare earth (more than 5 mg) appear towards the end of the elution, the separation is little affected this case approaches that of a tracer mixture of rare earths; if on the other hand weighable quantities of the rare earth are washed through at the beginning of the chromatogram, the dilution must be adjusted in order to obtain a good separation. (author)

  5. Mechanism of effect of rare earth oxides on high temperature corrosion resistance of weld metal

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-yong; WANG Bao; ZHANG Han-qian

    2006-01-01

    Through the addition of rare earth oxides into the coating of electrodes, the high temperature oxidation and sulphidation resistance of weld metal were studied. The transfer mechanism of rare earth oxides from coating to the welding pool and the physicochemical reaction during the process were analyzed. With the application of scanning electron microscope and energy spectrometer, the mechanism of weld metal corrosion in air and sulphur environment were studied. The result shows that the addition of rare earth oxides can improve the high temperature resistance of weld metal, especially in sulphidation environment. The electrodes in which La2O3 is added have better performance than the electrodes in which CeO2 is added. The existence form and distribution characteristic of rare earth are defined. It is believed that the marked effect of rare earth oxides in sulphur environment is related to the corrosion mechanism.

  6. Energy transfer and NIR emission in rare earth tri-doped barium lanthanum fluoro tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, J. Suresh; Pavani, K.; Graca, M.P.F.; Soares, M.J. [Department of Physics and I3N, University of Aveiro (Portugal); Venkataiah, G. [Department of Physics, Sri Venkateswara University, Tirupati (India); Jayasimhadri, M. [Department of Applied Physics, Delhi Technological University, Delhi (India)

    2014-09-15

    Barium lanthanum fluoro tellurite (BLFT) glasses doped with rare earth ions (ErF{sub 3}, PrF{sub 3} and YbF{sub 3}) both singly or in combinations were prepared by melt-quench technique and analysed spectroscopically. The prepared glasses were found to be mechanically strong and transparent. Optical absorption and NIR fluorescence were measured to the highly transparent and stable glass samples. Judd-Ofelt parameters and radiative properties were estimated for the single rare earth doped BLFT glasses using the optical absorption spectra. NIR fluorescence is measured using laser excitation. From the NIR emission spectra, energy transfer among the rare earth ions is analysed in the rare earth tri-doped BLFT glasses. These rare earth tri-doped BLFT glasses are found to be highly useful for the multi- wavelength emission in the NIR region for opto-electronic applications. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Energy transfer and NIR emission in rare earth tri-doped barium lanthanum fluoro tellurite glasses

    International Nuclear Information System (INIS)

    Barium lanthanum fluoro tellurite (BLFT) glasses doped with rare earth ions (ErF3, PrF3 and YbF3) both singly or in combinations were prepared by melt-quench technique and analysed spectroscopically. The prepared glasses were found to be mechanically strong and transparent. Optical absorption and NIR fluorescence were measured to the highly transparent and stable glass samples. Judd-Ofelt parameters and radiative properties were estimated for the single rare earth doped BLFT glasses using the optical absorption spectra. NIR fluorescence is measured using laser excitation. From the NIR emission spectra, energy transfer among the rare earth ions is analysed in the rare earth tri-doped BLFT glasses. These rare earth tri-doped BLFT glasses are found to be highly useful for the multi- wavelength emission in the NIR region for opto-electronic applications. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Decomposition of bastnasite and monazite mixed rare earth minerals calcined byalkali liquid

    Institute of Scientific and Technical Information of China (English)

    XU Yanhui; LIU Haijiao; MENG Zhijun; CUI Jianguo; ZHAO Wenyi; LI Liangcai

    2012-01-01

    The process of decomposion of the bastnasite and monazite rare earth concentrates by alkali solutions was investigated.The mixed slurries of the rare earth concentrates and the alkali solutions were calcined at different temperatures in a rotary tubular electric furnace.The effects of calcination temperature on the decomposing ratio of rare earth,the oxidation ratio of cerium,the stripping of fluorine and phosphorous after calcinations,and the adaptability of the process to the mixed rare earth concentrates of different grade were studied.The results showed that the decomposition ratio of rare earth and the oxidation ratio of cerium could reach 95.8% and 93.7%,respectively,while the calcinating temperature was above 300 ℃.

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

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    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.

  10. Separation of Rare Earth Elements from Monazite Ore Decomposition Process by Ion Exchange Column

    International Nuclear Information System (INIS)

    Separation of rare earth elements from monazite ore decomposition process was studied by using ion exchange columns filled with Dowex 50 WX8 resin. Mixed rare earth chloride from monazite composed of La, Ce, Pr, Nd, Y, Sm, Gd and Dy was adsorbed by resin in the column and 0.015 M EDTA was used to elute adsorbed rare earth elements through columns of Cu+2 adsorbed resin at linear flow rate of 0.636 and 0.212 cm/min. It was found that rare earth elements were eluted respectively by their atomic weight from heavy to light elements except Y which are Dy, Y, Gd, Sm, Nd, Pr, Ce and La. Ion exchange column has shown a potential method in separation and purification of individual rare earth elements

  11. Viscosity and thermal expansion of rare earth containing soda-lime-silicate glass

    International Nuclear Information System (INIS)

    Viscosity, coefficient of thermal expansion, glass transition temperature and dilatometric softening temperature of soda-lime-silicate glass doped with rare earth oxides (La2O3, CeO2, Nd2O3) were investigated by the rotating crucible viscometer and dilatometry, the melting temperature and activation energy for viscous flow of the studied melt were derived on the basis of Arrhenius equation, in order to reveal the effects of rare earth elements on the behavior of soda-lime-silicate glass. The results show that introduction of rare earth oxides increases the coefficient of thermal expansion, decreases viscosity of soda-lime-silicate glass, and Nd2O3 is an exception in viscosity. The glass transition temperature, dilatometric softening temperature, melting temperature and activation energy for viscous flow of soda-lime-silicate glass doped with rare earth oxides increase with increasing cationic field strength of corresponding rare earth ions.

  12. Role of multi-microalloying by rare earth elements in ductilization of magnesium alloys

    Directory of Open Access Journals (Sweden)

    Yuanding Huang

    2014-03-01

    Full Text Available The present work investigates the influences of microalloying with rare earths on the mechanical properties of magnesium alloys. The amount of each rare earth element is controlled below 0.4 wt.% in order not to increase the cost of alloy largely. The synergic effects from the multi-microalloying with rare earths on the mechanical properties are explored. The obtained results show that the as-cast magnesium alloys multi-microalloying with rare earths possesses a quite high ductility with a tensile strain up to 25–30% at room temperature. Moreover, these alloys exhibit much better corrosion resistance than AZ31 alloy. The preliminary in situ neutron diffractions on the deformation of these alloys indicate that the multi-microalloying with rare earths seems to be beneficial for the activation of more slip systems. The deformation becomes more homogeneous and the resultant textures after deformation are weakened.

  13. Extraction of rare earths from effluent generated during uranium purification

    International Nuclear Information System (INIS)

    Effluent generated during Uranium purification at TDP using tributylphosphate (TBP) extraction is mainly a nitrate solution containing Rare Earth Elements (REE) like Y (5-6 gm/L), Yb (3-4 gm/L), Er (500-1000 mg/L) along with others like U (20-30 mg/L), Fe, Na (20-25 gm/L), Ca (1-1.5 gm/L), NO3- (300-350 gm/L), P (3-4 gm/L). This solution was taken up as feed for REE extraction studies using TBP as extractant in Heavy Normal Paraffin (HNP) diluent. TBP (Brand name TOPS . 03TM, > 99.0% by GC) used in this studies was produced at HWP, Talcher. The free acidity of the feed was adjusted to ≈1N. HNP was chosen as diluent due to its higher Flash Point (F.P. 95℃) than earlier reported kerosene (F.P. 75), benzene (F.P. - 11.6℃) ), Xylene (F.P. 32℃)) etc. The percentage extraction (%E) of REE increased initially with increase in TBP concentration to a certain value and thereafter at further higher concentrations there was no considerable change. Solvents were pre-equilibrated with HNO3. The extraction conditions were O/A = 1, Tmix: 30 min, Tsep: 2 Hrs, T: 25℃) . The samples were analysed using ICP-OES (HORIBA Jobin Yvon make). Mixing for fixed time at a fixed RPM was made in a beaker using a magnetic needle on the magnetic stirrer in both extraction and stripping studies

  14. Chemical compatibility of rare earth cobaltite perovskites with YSZ

    International Nuclear Information System (INIS)

    Rare earth cobaltite perovskites are interesting cathode materials for the reduced temperature SOFC because of their high catalytic activity for oxygen reduction. The chemical compatibility of perovskites in Ln1-xSrxCoO3-δ(Ln=Sm, Dy), Ln0.4Sr0.6Co0.8Fe0.2O3-δ (Ln=La, Pr, Nd, Sm, Gd), Gd0.8Ca0.2Co1-xMnxO3-δ with 8 mol% yttria stabilized zirconia(8YSZ) has been investigated. Powder mixtures of these perovskites and 8YSZ have been annealed at different temperatures for 96 h in air. As the main reaction product, SrZrO3 has been found in 8YSZ/Ln, 1-xSrxCoO3-δ(Ln=Sm,Dy) with high Sr content and 8YSZ/Ln0.4Sr0.6Co0.8Fe0.2O3-δ (Ln=La,Pr,Nd,Sm,Gd) at 900 deg C. No reaction product has been detected in 8YSZ/Gd0.8Ca0.2Co1-6MnxO3-δ by XRD. However, significant diffusion of Co into 8YSZ has been found by EDX at the interface of 8YSZ/ Gd0.8Ca0.2Co0.6Mn0.4O3-δ after annealing at 1200 deg C for 24h. The bond-valence model has been used to discuss the chemical compatibility of the different perovskites with 8YSZ. Copyright (1999) Australasian Ceramic Society

  15. Rare Earth Element Partitioning in Lunar Minerals: An Experimental Study

    Science.gov (United States)

    McIntosh, E. C.; Rapp, J. F.; Draper, D. S.

    2016-01-01

    The partitioning behavior of rare earth elements (REE) between minerals and melts is widely used to interpret the petrogenesis and geologic context of terrestrial and extra-terrestrial samples. REE are important tools for modelling the evolution of the lunar interior. The ubiquitous negative Eu anomaly in lunar basalts is one of the main lines of evidence to support the lunar magma ocean (LMO) hypothesis, by which the plagioclase-rich lunar highlands were formed as a flotation crust during differentiation of a global-scale magma ocean. The separation of plagioclase from the mafic cumulates is thought to be the source of the Eu depletion, as Eu is very compatible in plagioclase. Lunar basalts and volcanic glasses are commonly depleted in light REEs (LREE), and more enriched in heavy REEs (HREE). However, there is very little experimental data available on REE partitioning between lunar minerals and melts. In order to interpret the source of these distinctive REE patterns, and to model lunar petrogenetic processes, REE partition coefficients (D) between lunar minerals and melts are needed at conditions relevant to lunar processes. New data on D(sub REE) for plagioclase, and pyroxenes are now available, but there is limited available data for olivine/melt D(sub REE), particularly at pressures higher than 1 bar, and in Fe-rich and reduced compositions - all conditions relevant to the lunar mantle. Based on terrestrial data, REE are highly incompatible in olivine (i.e. D much less than 1), however olivine is the predominant mineral in the lunar interior, so it is important to understand whether it is capable of storing even small amounts of REE, and how the REEs might be fractionatied, in order to understand the trace element budget of the lunar interior. This abstract presents results from high-pressure and temperature experiments investigating REE partitioning between olivine and melt in a composition relevant to lunar magmatism.

  16. Rare earth element analysis indicates micropollutants in an urban estuary

    Science.gov (United States)

    Mohajerin, T. J.; Johannesson, K. H.; Kolker, A.; Burdige, D. J.; Chevis, D.

    2011-12-01

    Rare earth element analysis of Bayou Bienvenue waters shows anomalously high gadolinium, Gd, concentrations relative to its nearest neighbors in the REE series, europium and terbium. The anomalously high Gd concentrations indicate anthropogenic input from waste-water treatment plants in the area as anthropogenic Gd input can be traced back to its use as a contrast agent in magnetic resonance imaging in hospitals. Others have shown that anomalously high levels of Gd in natural waters are likely to be associated with other micropollutants that also occur in hospital effluent and that are not removed in the wastewater treatment process, including pharmaceuticals in the form of steroids, antihistamines, and antibiotics. Estuaries serve as many important ecological roles and have been shown to act as a filter for pollutants. To better understand the transport, biogeochemical cycling, and ultimate fate of trace elements in estuaries, I collected surface water samples from Bayou Bienvenue, a wetland triangle that covers an area of 427 acres directly adjacent to New Orleans, Louisiana. Water samples from Bayou Bienvenue were collected along the salinity gradient and subsequently filtered through progressively smaller pore-size filters. The resulting fractions were analyzed for trace element concentions, including the REEs, by magnetic sector ICP-MS. The attached figure shows the Gd anomaly present in the particulate (>0.45μm) fraction. Upper continental crust (UCC)-normalized plots of colloidal REEs (0.02μm - 0.45μm) fraction is lacking this anomaly indicating anthropogenic Gd is found chiefly in the particulate fraction in Bayou Bienvenue. No clear relationship between Gd concentration and salinity was apparent.

  17. Pyrohydrolysis of rare-earth trifluorides in moist air

    Science.gov (United States)

    Yonezawa, Susumu; Jae-Ho, Kim; Takashima, Masayuki

    2002-11-01

    The kinetics of pyrohydrolysis of rare-earth trifluorides, LnF 3 (Ln = Y and La-Lu) have been investigated by means of thermogravimetry. There were two definite breaks on the TG curves that correspond to the conversion of LnF 3 into LnOF and from LnOF into Ln 2O 3, except for CeF 3. The beginning temperature of pyrohydrolysis decreased gradually and the reaction rate increased with increasing the acidity of Ln 3+ due to decrease of the ionic radius. The rate equation of conversion from LnF 3 to LnOF was expressed by [1-(1- x) 1/3]= kt, where x is defined as the reaction ratio, with x=1 when LnF 3 is completely transformed into LnOF. This rate equation is derived as the tarnishing reaction (LnF 3 particle is covered with LnOF layer) in which the rate-determining step is the surface reaction. It was assumed that cracks as gas paths were formed in the LnOF layer produced from the surface of sample particles, because of the smaller molar volume of LnOF compared with LnF 3. On the reaction from LnF 3 to LnOF, Ln 4O 3F 6 was detected in the XRD pattern. From the results of the kinetic study, the activation energy of pyrohydrolysis of LnF 3 decreased with increasing Ln 3+ atomic number by the same reason as the decrease of starting temperature of pyrohydrolysis.

  18. Fertiliser characterisation: Major, trace and rare earth elements

    Energy Technology Data Exchange (ETDEWEB)

    Otero, N. [Departament de Cristal lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain)]. E-mail: notero@ub.edu; Vitoria, L. [Departament de Cristal lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain); Soler, A. [Departament de Cristal lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain); Canals, A. [Departament de Cristal lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain)

    2005-08-15

    In recent years, there has been increasing concern regarding the chemical impact of agricultural activities on the environment so it is necessary to identify contaminants, and/or characterise the sources of contamination. In this study, a comprehensive chemical characterisation of 27 fertilisers of different types used in Spain has been conducted; major, minor and trace elements were determined, including rare earth elements. Results show that compound fertilisers used for fertigation or foliar application have low content of heavy metals, whereas fertilisers used for basal and top dressing have the highest content of both REE and other heavy metals. REE patterns of fertilisers have been determined in order for them to be used as tracers of fertilisers in future environmental studies. Furthermore in this work REE patterns of fertilisers are used as tracers of the source of phosphate in compound fertilisers, distinguishing between phosphorite and carbonatite derived fertilisers. Fertilisers from carbonatites have higher contents of REE, Sr, Ba and Th whereas fertilisers from phosphorites have higher contents of metals of environmental concern, such as Cd, U and As; and the sum of the heavy metals is higher. Some of the analysed fertilisers have Cd concentrations that exceed maximum values established in some countries and can be expected to produce long-term soil accumulation. Furthermore, other elements such as U, As and Cr are 10-50 times higher in concentration than those of Cd, but there is no legislation regarding them, therefore it is necessary to regulate fertiliser compositions in order to achieve environmental protection of soils and waters.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Accumulation of Rare Earth Elements in Various Microorganisms

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The removal of rare earth elements (REEs) from solution in various microorganisms was examined. Seventy-six strains from 69 species (22 bacteria, 20 actinomycetes, 18 fungi, and 16 yeasts) were tested. Initially, Sm was used to test the removal capabilities of the various organisms. Gram-positive bacteria, such as Bacillus licheniformis, B. subtilis, Brevibacterium helovolum, and Rhodococcus elythropolis, exhibited a particularly high capacity for accumulating Sm. In particular, the B. lichemiformis cells accumulated approximately 316 μmol Sm per gram dry wt. of microbial cells. A full suite of screenings was then conducted to compare the abilities of the organisms to remove Sc, Y, La, Er, and, Lu from solution. Tests were done with solutions containing one REE at a time. Accumulation was nearly identical for the various metals and organisms. However, when solutions with equimolar amounts of two REEs were used, preferential removal from solution was observed. When an Eu/Gd solution was used, gram-positive bacteria removed more Eu and Gd as compared to actinomycetes. When Eu/Sm combination was used, gram-positive bacteria removed equal mounts of both metals and some actinomycetes removed more Eu. The selective removal was quantified by calculating separation factors (S. F.), which indicated that Streptomyces levoris cells accumulated the greatest proportion of Eu. The removal of REEs from a solution containing five metals (Y, La, Sm, Er, and Lu) was then examined. Mucor javanicus preferentially accumulated Sm and S. flavoviridis preferentially accumulated Lu. The effects of pH and Sm concentration on the accumulation of Sm by B. licheniformis were also examined. Accumulation increased at higher pH and at greater solution concentrations.

  1. Carbonatite and alkaline intrusion-related rare earth element deposits–A deposit model

    Science.gov (United States)

    Verplanck, Philip L.; Van Gosen, Bradley S.

    2011-01-01

    The rare earth elements are not as rare in nature as their name implies, but economic deposits with these elements are not common and few deposits have been large producers. In the past 25 years, demand for rare earth elements has increased dramatically because of their wide and diverse use in high-technology applications. Yet, presently the global production and supply of rare earth elements come from only a few sources. China produces more than 95 percent of the world's supply of rare earth elements. Because of China's decision to restrict exports of these elements, the price of rare earth elements has increased and industrial countries are concerned about supply shortages. As a result, understanding the distribution and origin of rare earth elements deposits, and identifying and quantifying our nation's rare earth elements resources have become priorities. Carbonatite and alkaline intrusive complexes, as well as their weathering products, are the primary sources of rare earth elements. The general mineral deposit model summarized here is part of an effort by the U.S. Geological Survey's Mineral Resources Program to update existing models and develop new descriptive mineral deposit models to supplement previously published models for use in mineral-resource and mineral-environmental assessments. Carbonatite and alkaline intrusion-related REE deposits are discussed together because of their spatial association, common enrichment in incompatible elements, and similarities in genesis. A wide variety of commodities have been exploited from carbonatites and alkaline igneous rocks, such as rare earth elements, niobium, phosphate, titanium, vermiculite, barite, fluorite, copper, calcite, and zirconium. Other enrichments include manganese, strontium, tantalum, thorium, vanadium, and uranium.

  2. Rare earth ion modified TiO2 sols for photocatalysis application under visible light excitation

    Institute of Scientific and Technical Information of China (English)

    XIE Yibing; YUAN Chunwei

    2004-01-01

    TiO2 sols modified by rare earth (RE) ions (Ce4+, Eu3+, or Nd3+) were prepared by coprecipitation-peptization method. The photocatalysis activity was studied by investigating the photodegradation effects of active brilliant red dye X-3B. It is found that TiO2 sols modified by Ce4+, Eu3+, or Nd3+ have the anatase crystalline structure, which are prepared at 70°C. All REn+-TiO2 sol samples have uniform nanoparticles with similar morphology, which are homogenously distributed in aqueous colloidal systems. The particle sizes are 10, 8, and 12 nm for Nd3+-TiO2, Eu3+-TiO2, and Ce4+-TiO2, respectively.The character of ultrafine and positive charge sol particles contributes to the good adsorption of X-3B dye molecule on the surface of titania (about 30% X-3B adsorption amount). Experimental results exhibit that REn+-TiO2 sol photocatalysts have the capability to photodegrade X-3B under visible light irradiation. Nd3+-TiO2 and Eu3+-TiO2 show higher photocatalytic activity than Cea+-TiO2, which is due to the difference of standard redox potential of REn+/RE(n-1)+. REn+-TiO2 sols demonstrate more excellent interfacial adsorption and photodegradation effects to X-3B than P25 TiO2 crystallites. Moreover, the degradation mechanism of X-3B is proposed as dye photosensitization and electron scavenging by rare earth ions.

  3. Chemical equilibrium constants of rare earth nitrates and tri-n-butyl phosphate complex formation

    Institute of Scientific and Technical Information of China (English)

    Kalaya Changkrueng; Deacha Chatsiriwech

    2011-01-01

    Mixed rare earth nitrates (REi(NO3)3) in the aqueous solution was mixed with tri-n-butyl phosphate (TBP,(n-C4H9O)3PO) dissolved in kerosene for the formation of their corresponding complexes (REi(NO3)3·n1(n-C4H9O)3PO) at 303 K.The effects of initial concentrations of both TBP and mixed rare earth nitrates on the equilibrium constants of their complex formations were investigated.The complexes were formed almost immediately after mixing.The simultaneous formations reached their chemical equilibria within a few minutes by shaking the mixture at 200 r/min.The chemical equilibrium constants of the complex formations were independent of the initial TBP concentrations.However,they were decreased by reducing the concentration of REi(NO3)3.All equilibrium constants of the simultaneous complex formations were less than 0.7,while the average molar ratio of TBP to REi(NO3)3 of the complexes varied between 1.0 and 1.6.The chemical equilibrium constant for the formation of La(NO3)3·(n-C4HgO)3PO was 0.09,while that of Dy(NO3)3·(n-CaH9O)3PO was 0.68.The ascending sequence of chemical equilibrium constants for the simultaneous formations was La,Ce,Pr,Nd,Eu,Y,Srn,Gd,and Dy.

  4. Removal of Uranium and Thorium from Kvanefjeld Rare Earth Intermediate Product

    International Nuclear Information System (INIS)

    Rare earth elements are commonly encountered in close geological association with radioactive minerals. In particular, thorium is often found in the same minerals as rare earth elements, making their combined treatment necessary. The paper discusses the metallurgical flowsheet developed for the Kvanefjeld rare earth and uranium deposit located in southern Greenland. The Kvanefjeld and associated deposits are well recognized as one of the largest rare earth and uranium deposits in the world. The minerals which contain the rare earth elements also contain economically viable amounts of uranium and potentially economically viable amounts of thorium. Metallurgical studies using flotation have been successful in producing a high grade concentrate which consists of 13% rare earth oxide, 0.2% triuranium octaoxide and 0.8% thorium. Due to the unique nature of the minerals contained within the deposit, a customized hydrometallurgical flowsheet was developed to treat the concentrate. The hydrometallurgical flowsheet has been well tested and is capable of producing a high grade mixed rare earth product which is very low in uranium and thorium. A separate uranium oxide product can also be produced using commercially established solvent extraction. The Kvanefjeld project is currently at the feasibility study stage, with metallurgical designs of both the concentrator and hydrometallurgical plant well advanced. The paper discusses the metallurgical flowsheet and show the deportment of NORM throughout the flowsheet. The issues of NORM deportment and strategies for removal and safe disposal are also discussed. (author)

  5. Processes for the production of rare earths from monazite (Paper No. 36)

    International Nuclear Information System (INIS)

    A few typical cases are briefly described to illustrate different methods available for rare earth concentration and separation from mixed rare earths chloride obtained for monazite. In the case of cerium, rare earths chloride mixture is treated with sodium sulphate to precipitate rare earths as double sulphates from which hydroxide cake is prepared. The cake is dried to oxidise cerium. Trivalent rare earths are selectively leached and the product is treated with HNO3. The resulting ceric nitrate solution is purified by liquid-liquid extraction using TBP. The scrubbed extract is reduced with H2O2 and cerous nitrate is recovered by evaporation. Lanthanum is first concentrated by selective precipitation of hydroxides from rare earths chloride using air-ammonia mixture. The hydroxyde cake is dissolved in HNO3 and NH4NO3 to get the double nitrate which is subjected to counter current crystallisation for purification. Europium is present at a concentration of 0.01% in the rare earths chloride. It is concentrated in several steps by liquid-liquid extraction using di-2-ethyl hexyl phosphoric acid. The product is purified by selective reduction and europium is obtained as europium sulphate. In the same solvent extraction process samarium and gadolinium are also concentrated to about 25%. They are further upgraded to above 90% purity by repetion of liquid-liquid extraction technique. Cerium, lanthanum and europium obtained by the above processes analyse > 99% as oxides. (M.G.B.)

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

    Directory of Open Access Journals (Sweden)

    Timothy Ault

    2015-03-01

    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.

  7. Influence of Rare Earth Element Supply on Future Offshore Wind Turbine Generators

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Abrahamsen, Asger Bech; Henriksen, Matthew Lee

    2011-01-01

    , highlighting their advantages and disadvantages in serving as long term solutions for offshore wind farms. Finally, a direct drive induction generator and a high temperature superconducting generator topology, which respectively are not and very little dependent on rare earth elements, are presented as...... earth material, and there are indications that Chinese rare earth exports will decrease in the near future as China seeks to maintain a sufficient supply of these materials. The magnetic properties of some particular rare-earth elements have made them very useful in producing high power density...... electrical machines. Such machines are utilized in applications such as electric cars, and wind turbines. This paper will examine the rare earth supply issue, in order to comment on its relevance to the wind turbine industry. The wind turbine topologies which are currently being used are compared...

  8. Structure and properties of intermetallic ternary rare earth compounds

    International Nuclear Information System (INIS)

    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

  9. Rare Earth elements as sediment tracers in Mangrove ecosystems

    Science.gov (United States)

    Ramanathan, A. L.; Swathi, S.

    2013-05-01

    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

  10. Investigating Rare Earth Element Systematics in the Marcellus Shale

    Science.gov (United States)

    Yang, J.; Torres, M. E.; Kim, J. H.; Verba, C.

    2014-12-01

    The lanthanide series of elements (the 14 rare earth elements, REEs) have similar chemical properties and respond to different chemical and physical processes in the natural environment by developing unique patterns in their concentration distribution when normalized to an average shale REE content. The interpretation of the REE content in a gas-bearing black shale deposited in a marine environment must therefore take into account the paleoredox conditions of deposition as well as any diagenetic remobilization and authigenic mineral formation. We analyzed 15 samples from a core of the Marcellus Shale (Whipkey ST1, Greene Co., PA) for REEs, TOC, gas-producing potential, trace metal content, and carbon isotopes of organic matter in order to determine the REE systematics of a black shale currently undergoing shale gas development. We also conducted a series of sequential leaching experiments targeting the phosphatic fractions in order to evaluate the dominant host phase of REEs in a black shale. Knowledge of the REE system in the Marcellus black shale will allow us to evaluate potential REE release and behavior during hydraulic fracturing operations. Total REE content of the Whipkey ST1 core ranged from 65-185 μg/g and we observed three distinct REE shale-normalized patterns: middle-REE enrichment (MREE/MREE* ~2) with heavy-REE enrichment (HREE/LREE ~1.8-2), flat patterns, and a linear enrichment towards the heavy-REE (HREE/LREE ~1.5-2.5). The MREE enrichment occurred in the high carbonate samples of the Stafford Member overlying the Marcellus Formation. The HREE enrichment occurred in the Union Springs Member of the Marcellus Formation, corresponding to a high TOC peak (TOC ~4.6-6.2 wt%) and moderate carbonate levels (CaCO3 ~4-53 wt%). Results from the sequential leaching experiments suggest that the dominant host of the REEs is the organic fraction of the black shale and that the detrital and authigenic fractions have characteristic MREE enrichments. We present our

  11. Structure and properties of intermetallic ternary rare earth compounds

    Energy Technology Data Exchange (ETDEWEB)

    Casper, Frederick

    2008-12-17

    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

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

    Science.gov (United States)

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

    2016-03-01

    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 310tons, 980tons and 80tons rare earth metal resp., while recycled flows are 35tons, 110tons and 30tons 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. PMID:26818182

  13. Biogeochemistry of the rare-earth elements with particular reference to hickory trees

    Science.gov (United States)

    Robinson, W.O.; Bastron, H.; Murata, K.J.

    1958-01-01

    Hickory trees concentrate the rare-earth elements in their leaves to a phenomenal degree and may contain as much as 2300 p.p.m. of total rare earths based on the dry weight of the leaves. The average proportions of the individual elements (atomic percent of the total rare-earth elements) in the leaves are: Y 36, La 16, Ce 14, Pr 2, Nd 20, Sm 1, Eu 0.7, Gd 3, Tb 0.6, Dy 3, Ho 0.7, Er 2, Tm 0.2, Yb 1, and Lu 0.2. The similarity in the proportions of the rare-earth elements in the leaves and in the exchange complex of the soil on which the hickory trees grow indicates that the trees do not fractionate the rare earths appreciably. The variation of the rare-earth elements in the leaves and soils can be explained generally in terms of the relative abundance of the cerium group and the yttrium group, except for the element cerium. The large fluctuations in the proportion of cerium [Ce/(La + Nd) atomic ratios of 0.16 to 0.86] correlate with oxidation-reduction conditions in the soil profile. The substitution of dilute H2SO3 for dilute HC1 in the determination of available rare-earth elements brings about a large increase in the proportion of cerium that is extracted from an oxygenated subsoil. These relationships strongly suggest that quadrivalent cerium is present in oxygenated subsoil and is less available to plants than the other rare-earth elements that do not undergo such a change in valence. A few parts per billion of rare-earth elements have been detected in two samples of ground water. ?? 1958.

  14. Proceedings of the national conference on rare earth processing and utilization - 2014: abstracts

    International Nuclear Information System (INIS)

    The rare earth elements (REEs) are becoming increasingly important in the transition to a low-carbon, circular economy, considering their essential role in permanent magnets, lamp phosphors, rechargeable nickel metal hydride batteries and catalysts and other green applications. The increasing popularity of hybrid and electric cars, wind turbines and compact fluorescent lamps is causing an increase in the demand and price of REEs. The European Commission considers the REEs as the most critical raw materials group, with the highest supply risk. According to the medium-term criticality matrix of the U.S. Department of Energy (DOE), the five most critical REEs are neodymium (Nd), europium (Eu), terbium (Tb), dysprosium (Dy) and yttrium (Y). China is presently producing more than 90% of all rare earths, although they possess less than 40% of the proven reserves. Due to large and increasing domestic demands, China tightened its REE export quota from 2012 onwards. These export quotas caused serious problems for REE users outside of China. To tackle the REE supply challenge, several approaches have been proposed. Fortunately India is blessed with large resources of rare earths in the form of monazite found in the beach sands of Kerala, Tamil Nadu and Odisha. Indian Rare Earths Limited at Aluva near Kochi used to produce mainly mixed rare earths chloride and export to USA, UK, France, Japan, etc. During the 1990s and early 2000s this plant exported pure oxides of samarium, neodymium, etc. to developed countries. This national conference has expanded its canvas by including newer emerging areas in rare earths recycling, environmental issues, recent advances in rare earth material science, rare earth research and development initiatives around the world which provide a platform for the growth of rare earth Industry. Papers relevant to INIS are indexed separately

  15. Study On Beneficiation Technology Of Dong Pao Rare-Earth-Barite-Fluorite With Two Product Plans About Content And Recovery Of Rare-Earth Fine Ores

    International Nuclear Information System (INIS)

    The ore sample used in the research was taken from the F3 ore bodies and the sample of the F7, F9 and F16 ore bodies which contain the average of 5.98% TR2O3; they are multi-metals ore which is difficult to enrich, highly weather with very complex ingredients. The process of the experiment is the ore is crushed, ground, screened and classified reasonably to -0.1 mm and divided into 3 particle size with the following technique: (1) -0.020 mm is primary sludge and the rare-earth fine ore; (2) 0.075-1 mm is gotten through the sludge concentrating table with the output is the 2 parts: the heavy part which is dried magnetic separator with high magnetism to get the rare-earth fine ore and the light one; (3) Light minerals, non-magnetic and ferromagnetic minerals group are ground together to 85% of them get size within -0.075 mm then mix it with 0.020-0.075 mm group. Using flotation separator, get barite-rare earth mixture and fluorite. After that, we separate this mixture by secondary flotation and get refined rare earth, barite and fluorite mineral. The result of the theme: (1) product plan A-rare-earth fine ore has TR2O3 content archive 42.07% with recovery is 69.70%; (2) product plan B-rare-earth fine ore has TR2O3 content archive 29.64% with recovery is 80.01%. (author)

  16. Studies on Standard Formation Enthalpies of Rare Earth Compounds by Using Structural Parameters

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The atomic structural parameter Pi=(Zi*/ni*) (1+ni*/ni) (1+mi/Z) and the molecular structural parameter P=Σni=1Pi are defined. The standard formation enthalpies (ΔfHφm) of 74 species of rare earth compounds were studied with P, and the correlation coefficient is R>0.94. The structural factors and the properties of rare earth compounds are influenced by the Zi*, ni*, ni, mi, Z. This study has special referential value to predict the properties of rare earth compounds.

  17. Synthesis and Characterization of Rare Earth Solid Complexes with Sodium 5-Aminosalicylate

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiuying; Li Shujing; Lei Xuefeng; Ma Junxian

    2005-01-01

    Ten new rare earth solid complexes were synthesized by the reaction of sodium 5-aminosalicyliate with rare earth chloride. The structure character, physical and chemical properties of these complexes were studied by IR, UV, 1H NMR spectra, TG-DTA, fluorescence, elemental analyses, molar conductance and magnetic susceptibility. The ten rare earth complexes exist in dimeric form probably and the coordination number is seven. The antibacterial activity of the ligand and six complexes was also tested against Staphylococcus aureus, Escherichia coli and Bacillus subtilis, and the effect of Yb complex at 20 mg·ml-1 against Staphylococcus aureus is most significant.

  18. Effect of Rare Earths on Corrosion Resisting Properties of Carbon-Manganese Clean Steels

    Institute of Scientific and Technical Information of China (English)

    郭锋; 林勤; 孙学义

    2004-01-01

    Electrochemistry experiments were made on carbon-manganese clean steel with rare earths Ce and La respectively to observe corrosion parameters such as corrosion current icorr, and characteristic potential of pitting Eb. The results indicate that the rare earths have effect on corrosion resisting properties of carbon-manganese clean steel, and the optimum contents of La is about 0.011% (mass fraction) and Ce about 0.014% (mass fraction) respectively. The change of corrosion resistance is related to the action of rare earths on microstructure and effect on surface state of samples in the process of polarization.

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

    Institute of Scientific and Technical Information of China (English)

    由芳田; 黄世华; 时秋峰

    2010-01-01

    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...

  20. Rare Earth Application in Sealing Anodized Al-Based Metal Matrix Composites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new method for corrosion protection of Al-based metal matrixcomposites (MMC) was developed using two-step process, which involves anodizing in H2SO4 solution and sealing in rare earth solution. Corrosion resistance of the treated surface was evaluated with polarization curves.The results showed that the effect of the protection using rare earth sealing is equivalent to that using chromate sealing for Al6061/SiCp. The rare earth metal salt can be an alternative to the toxic chromate for sealing anodized Al MMC.