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Sample records for rubidium-cesium-rare earth element

  1. Scarcity of rare earth elements.

    PubMed

    de Boer, M A; Lammertsma, K

    2013-11-01

    Rare earth elements (REEs) are important for green and a large variety of high-tech technologies and are, therefore, in high demand. As a result, supply with REEs is likely to be disrupted (the degree of depends on the REE) in the near future. The 17 REEs are divided into heavy and light REEs. Other critical elements besides REEs, identified by the European Commission, are also becoming less easily available. Although there is no deficiency in the earth's crust of rare earth oxides, the economic accessibility is limited. The increased demand for REEs, the decreasing export from China, and geopolitical concerns on availability contributed to the (re)opening of mines in Australia and the USA and other mines are slow to follow. As a result, short supply of particularly terbium, dysprosium, praseodymium, and neodymium is expected to be problematic for at least the short term, also because they cannot be substituted. Recycling REEs from electronic waste would be a solution, but so far there are hardly any established REE recycling methods. Decreasing the dependency on REEs, for example, by identifying possible replacements or increasing their efficient use, represents another possibility. PMID:24009098

  2. Rare earth element scavenging in seawater

    NASA Astrophysics Data System (ADS)

    Byrne, Robert H.; Kim, Ki-Hyun

    1990-10-01

    Examinations of rare earth element (REE) adsorption in seawater, using a variety of surface-types, indicated that, for most surfaces, light rare earth elements (LREEs) are preferentially adsorbed compared to the heavy rare earths (HREEs). Exceptions to this behavior were observed only for silica phases (glass surfaces, acid-cleaned diatomaceous earth, and synthetic SiO 2). The affinity of the rare earths for surfaces can be strongly affected by thin organic coatings. Glass surfaces which acquired an organic coating through immersion in Tampa Bay exhibited adsorptive behavior typical of organic-rich, rather than glass, surfaces. Models of rare earth distributions between seawater and carboxylate-rich surfaces indicate that scavenging processes which involve such surfaces should exhibit a strong dependence on pH and carbonate complexation. Scavenging models involving carboxylate surfaces produce relative REE abundance patterns in good general agreement with observed shale-normalized REE abundances in seawater. Scavenging by carboxylate-rich surfaces should produce HREE enrichments in seawater relative to the LREEs and may produce enrichments of lanthanum relative to its immediate trivalent neighbors. Due to the origin of distribution coefficients as a difference between REE solution complexation (which increases strongly with atomic number) and surface complexation (which apparently also increases with atomic number) the relative solution abundance patterns of the REEs produced by scavenging reactions can be quite complex.

  3. What about the rare-earth elements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is insufficient understanding of the nutritional physiology of pecan trees and orchards; thus, affecting nutmeat yield and quality, disease resistance and alternate bearing. An analysis of the rare-earth element composition of pecan and related hickory cousins found that they hyperaccumulate ...

  4. Rare earth element systematics in hydrothermal fluids

    SciTech Connect

    Michard, A. )

    1989-03-01

    Rare earth element concentrations have been measured in hydrothermal solutions from geothermal fields in Italy, Dominica, Valles Caldera, Salton Sea and the Mid-Atlantic Ridge. The measured abundances show that hydrothermal activity is not expected to affect the REE balance of either continental or oceanic rocks. The REE enrichment of the solutions increases when the pH decreases. High-temperature solutions (> 230{degree}C) percolating through different rock types may show similar REE patterns.

  5. Rare earth elements and permanent magnets (invited)

    NASA Astrophysics Data System (ADS)

    Dent, Peter C.

    2012-04-01

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

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

    PubMed

    Imashuku, Susumu; Fuyuno, Naoto; Hanasaki, Kohei; Kawai, Jun

    2013-12-01

    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. PMID:24387481

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

    SciTech Connect

    Imashuku, Susumu Fuyuno, Naoto; Hanasaki, Kohei; Kawai, Jun

    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.

  8. Anthropogenic Cycles of Rare Earth Elements

    NASA Astrophysics Data System (ADS)

    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

  9. Siderophile elements and the earth's formation

    NASA Technical Reports Server (NTRS)

    Jones, J. H.; Capobianco, C. J.; Drake, M. J.; O'Neill, Hugh

    1992-01-01

    Two comments on a work by Murthy (1991) concerning the abundances of siderophile elements in the earth's mantle are presented. In the first comment it is asserted that the basis of Murthy's extrapolation is the assumption that the Gibbs free energy change for the partitioning reaction is independent of temperature, and as this is generally not a valid assumption thermodynamically, and as this is contradicted by most experimental data, the issue of mantle siderophile elements remains unresolved. In the second comment it is asserted that the extrapolation method used by Murthy does not appear to be valid thermodynamically, and that an extrapolation based on generally accepted thermodynamic assumptions yields different results. In a reply, Murthy takes issue with the comments.

  10. Tipping elements in the Earth's climate system

    SciTech Connect

    Lenton, T.M.; Held, H.; Lucht, W.; Rahmstorf, S.; Kriegler, E. |; Hall, J.W.; Schellnhuber, H.J. |

    2008-02-12

    The term 'tipping point' commonly refers to a critical threshold at which a tiny perturbation can qualitatively alter the state or development of a system. Here the authors introduce the term 'tipping element' to describe large-scale components of the Earth system that may pass a tipping point. They critically evaluate potential policy-relevant tipping elements in the climate system under anthropogenic forcing, drawing on the pertinent literature and a recent international workshop to compile a short list, and they assess where their tipping points lie. An expert elicitation is used to help rank their sensitivity to global warming and the uncertainty about the underlying physical mechanisms. Then the authors explain how, in principle, early warning systems could be established to detect the proximity of some tipping points.

  11. Development of a Rare Earth Element Paleoproxy

    NASA Astrophysics Data System (ADS)

    Haley, B. A.; Klinkhammer, G. P.; McManus, J.

    2002-12-01

    The rare earth elements (REEs) have demonstrated considerable potential as paleoproxies for changes in seawater chemistry. However, their utilization in paleoceanographic investigations has been mainly limited to neodymium isotopic analyses in metalliferous deposits and fossil apatite. The goal of being able to use the entire group of elements in foraminiferal shells has proven difficult. The problem with analysis of these elements in this matrix stems mainly from: (1) the ability to clean the shells of diagenetic aberrations and (2) the paucity of REE data in the environment where forams obtain their primary signature. We recently measured pore water profiles of REEs using an interfaced Ion Chromatograph (IC) and Inductively Coupled Plasma Mass Spectrometer (ICP-MS) in a depth transect off the Coast of California, and a profile from off the Peru-Chile margin. The pore water results are surprising and will alter our view of REE marine geochemistry. For example, they call into question the traditional method of calculating a "Ce-anomaly." The profiles also show dramatic changes in REE concentrations and patterns with depth, and demonstrate that the REE signature preserved in epifaunal benthic versus infaunal foram species and diagenetically added phases should be easily identifiable. Preliminary REE results from forams cleaned via a recently developed flow-through technique will be shown and compared to matching pore water data. We will conclude by outlining the potential of foraminiferal REE content for paleoceanography that ranges from water mass tracer to proxies for organic carbon flux and oxygen concentration.

  12. Rare earth elements materials production from apatite ores

    NASA Astrophysics Data System (ADS)

    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.

  13. Rare earth elements in river waters

    NASA Technical Reports Server (NTRS)

    Goldstein, Steven J.; Jacobsen, Stein B.

    1988-01-01

    To characterize the input to the oceans of rare earth elements (REE) in the dissolved and the suspended loads of rivers, the REE concentrations were measured in samples of Amazon, Indus, Mississippi, Murray-Darling, and Ohio rivers and in samples of smaller rivers that had more distinct drainage basin lithology and water chemistry. It was found that, in the suspended loads of small rivers, the REE pattern was dependent on drainage basin geology, whereas the suspended loads in major rivers had relatively uniform REE patterns and were heavy-REE depleted relative to the North American Shale composite (NASC). The dissolved loads in the five major rivers had marked relative heavy-REE enrichments, relative to the NASC and the suspended material, with the (La/Yb)N ratio of about 0.4 (as compared with the ratio of about 1.9 in suspended loads).

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

    SciTech Connect

    Selle, J E

    1992-06-26

    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.

  15. Google Earth locations of USA and seafloor hydrothermal vents with associated rare earth element data

    DOE Data Explorer

    Andrew Fowler

    2016-02-10

    Google Earth .kmz files that contain the locations of geothermal wells and thermal springs in the USA, and seafloor hydrothermal vents that have associated rare earth element data. The file does not contain the actual data, the actual data is available through the GDR website in two tier 3 data sets entitled "Compilation of Rare Earth Element Analyses from US Geothermal Fields and Mid Ocean Ridge (MOR) Hydrothermal Vents" and "Rare earth element content of thermal fluids from Surprise Valley, California"

  16. Rare earth elements in Hamersley BIF minerals

    NASA Astrophysics Data System (ADS)

    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.

  17. Rare earth elements in the Amazon basin

    NASA Astrophysics Data System (ADS)

    Gerard, M.; Seyler, P.; Benedetti, M. F.; Alves, V. P.; Boaventura, G. R.; Sondag, F.

    2003-05-01

    The rare earth element (REE) concentrations of the dissolved and particulate fractions and bed sediment between Manaus and Santarém in the Amazon River, and in some major tributaries, were evaluated. A very important zone in the Amazon basin, the encontro das aguas area where the Rio Solimões and the Rio Negro meet, was especially sampled. Different size fractions were isolated by ultrafiltration. Water samples were collected at different stages of the mixing. Three groups of waters are distinguished: group I has a low pH (<5·5) and is represented by the Negro basin rivers; group II has alkalinity less than 0·2 meq l-1 and is represented by the Rios Tapajós and Trombetas; group III has high alkalinity (>0·2 meq l-1) and higher pH (>6·5) and is represented by the Madeira basin rivers, the Solimões and the Amazon. The highest dissolved REE concentration is in the Rio Negro and the lowest in the Rio Tapajós (dissolved REEs vary by more than a factor of ten). The solubility of REEs is pH dependent: in river waters with a pH < 6 the Ce concentration is twice that of La, whereas in rivers with a higher pH the concentrations of Ce and La are similar. Dissolved REE concentrations are positively correlated with the dissolved organic carbon. Correlations between Fe, Al, and La suggest that La is associated with Al (Fe)-rich organic matter and/or related to dissolved Fe-rich inorganic material. Dissolved REEs normalized to North American shale composite show an enrichment in intermediate/heavy REEs (from Eu to Er), except for the shields rivers (such as Rio Negro and Rio Trombetas). Both of them are depleted in heavy REEs and show a relative Ce enrichment. In contrast, for the Andeans rivers (such as Rio Solimões), light REEs are slightly depleted and a negative Ce relative anomaly occurs. The pattern of the Amazon River at Óbidos confirms the major influence of the Rios Negro and Solimões with REE fractionation. For the Rio Negro, 60 to 70% of REEs are

  18. Alkali element constraints on Earth-Moon relations

    NASA Technical Reports Server (NTRS)

    Norman, M. D.; Drake, M. J.; Jones, J. H.

    1994-01-01

    Given their range of volatilities, alkali elements are potential tracers of temperature-dependent processes during planetary accretion and formation of the Earth-Moon system. Under the giant impact hypothesis, no direct connection between the composition of the Moon and the Earth is required, and proto-lunar material does not necessarily experience high temperatures. Models calling for multiple collisions with smaller planetesimals derive proto-lunar materials mainly from the Earth's mantle and explicitly invoke vaporization, shock melting and volatility-related fractionation. Na/K, K/Rb, and Rb/Cs should all increase in response to thermal volatization, so theories which derive the Moon substantially from Earth's mantle predict these ratios will be higher in the Moon than in the primitive mantle of the Earth. Despite the overall depletion of volatile elements in the Moon, its Na/K and K/Rb are equal to or less than those of Earth. A new model presented here for the composition of Earth's continental crust, a major repository of the alkali elements, suggests the Rb/Cs of the Moon is also less than that of Earth. Fractionation of the alkali elements between Earth and Moon are in the opposite sense to predictions based on the relative volatilities of these elements, if the Moon formed by high-T processing of Earth's mantle. Earth, rather than the Moon, appears to carry a signature of volatility-related fractionation in the alkali elements. This may reflect an early episode of intense heating on Earth with the Moon's alkali budget accreting from cooler material.

  19. Earth, Air, Fire and Water in Our Elements

    ERIC Educational Resources Information Center

    Lievesley, Tara

    2007-01-01

    The idea that everything is made of the four "elements", earth, air, fire and water, goes back to the ancient Greeks. In this article, the author talks about the origins of ideas about the elements. The author provides an account that attempts to summarise thousands of years of theoretical development of the elements in a thousand words or so.

  20. Rare earth element association with foraminifera

    NASA Astrophysics Data System (ADS)

    Roberts, Natalie L.; Piotrowski, Alexander M.; Elderfield, Henry; Eglinton, Timothy I.; Lomas, Michael W.

    2012-10-01

    Neodymium isotopes are becoming widely used as a palaeoceanographic tool for reconstructing the source and flow direction of water masses. A new method using planktonic foraminifera which have not been chemically cleaned has proven to be a promising means of avoiding contamination of the deep ocean palaeoceanographic signal by detrital material. However, the exact mechanism by which the Nd isotope signal from bottom waters becomes associated with planktonic foraminifera, the spatial distribution of rare earth element (REE) concentrations within the shell, and the possible mobility of REE ions during changing redox conditions, have not been fully investigated. Here we present REE concentration and Nd isotope data from mixed species of planktonic foraminifera taken from plankton tows, sediment traps and a sediment core from the NW Atlantic. We used multiple geochemical techniques to evaluate how, where and when REEs become associated with planktonic foraminifera as they settle through the water column, reside at the surface and are buried in the sediment. Analyses of foraminifera shells from plankton tows and sediment traps between 200 and 2938 m water depth indicate that only ˜20% of their associated Nd is biogenically incorporated into the calcite structure. The remaining 80% is associated with authigenic metal oxides and organic matter, which form in the water column, and remain extraneous to the carbonate structure. Remineralisation of these organic and authigenic phases releases ions back into solution and creates new binding sites, allowing the Nd isotope ratio to undergo partial equilibration with the ambient seawater, as the foraminifera fall through the water column. Analyses of fossil foraminifera shells from sediment cores show that their REE concentrations increase by up to 10-fold at the sediment-water interface, and acquire an isotopic signature of bottom water. Adsorption and complexation of REE3+ ions between the inner layers of calcite contributes

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

    SciTech Connect

    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.

  2. Bioleaching of rare earth elements from monazite sand.

    PubMed

    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

  3. MaRGEE: Move and Rotate Google Earth Elements

    NASA Astrophysics Data System (ADS)

    Dordevic, Mladen M.; Whitmeyer, Steven J.

    2015-12-01

    Google Earth is recognized as a highly effective visualization tool for geospatial information. However, there remain serious limitations that have hindered its acceptance as a tool for research and education in the geosciences. One significant limitation is the inability to translate or rotate geometrical elements on the Google Earth virtual globe. Here we present a new JavaScript web application to "Move and Rotate Google Earth Elements" (MaRGEE). MaRGEE includes tools to simplify, translate, and rotate elements, add intermediate steps to a transposition, and batch process multiple transpositions. The transposition algorithm uses spherical geometry calculations, such as the haversine formula, to accurately reposition groups of points, paths, and polygons on the Google Earth globe without distortion. Due to the imminent deprecation of the Google Earth API and browser plugin, MaRGEE uses a Google Maps interface to facilitate and illustrate the transpositions. However, the inherent spatial distortions that result from the Google Maps Web Mercator projection are not apparent once the transposed elements are saved as a KML file and opened in Google Earth. Potential applications of the MaRGEE toolkit include tectonic reconstructions, the movements of glaciers or thrust sheets, and time-based animations of other large- and small-scale geologic processes.

  4. Modeling rammed earth wall using discrete element method

    NASA Astrophysics Data System (ADS)

    Bui, T.-T.; Bui, Q.-B.; Limam, A.; Morel, J.-C.

    2016-03-01

    Rammed earth is attracting renewed interest throughout the world thanks to its "green" characteristics in the context of sustainable development. Several research studies have thus recently been carried out to investigate this material. Some of them attempted to simulate the rammed earth's mechanical behavior by using analytical or numerical models. Most of these studies assumed that there was a perfect cohesion at the interface between earthen layers. This hypothesis proved to be acceptable for the case of vertical loading, but it could be questionable for horizontal loading. To address this problem, discrete element modeling seems to be relevant to simulate a rammed earth wall. To our knowledge, no research has been conducted thus far using discrete element modeling to study a rammed earth wall. This paper presents an assessment of the discrete element modeling's robustness for rammed earth walls. Firstly, a brief description of the discrete element modeling is presented. Then the parameters necessary for discrete element modeling of the material law of the earthen layers and their interfaces law following the Mohr-Coulomb model with a tension cut-off and post-peak softening were given. The relevance of the model and the material parameters were assessed by comparing them with experimental results from the literature. The results showed that, in the case of vertical loading, interfaces did not have an important effect. In the case of diagonal loading, model with interfaces produced better results. Interface characteristics can vary from 85 to 100% of the corresponding earthen layer's characteristics.

  5. Systematic variation of rare-earth elements in cerium-earth minerals

    USGS Publications Warehouse

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

    1957-01-01

    In a continuation of a study reported previously, rare-earth elements and thorium have been determined in monazite, allanite, cerite, bastnaesite, and a number of miscellaneous cerium-earth minerals. A quantity called sigma (???), which is the sum of the atomic percentages of La, Ce, and Pr, is proposed as an index of composition of all cerium-earth minerals with respect to the rare-earth elements. The value of ??? for all of the minerals analysed falls between 58 and 92 atomic per cent. Monazites, allanites, and cerites cover the entire observed range, whereas bastnaesites are sharply restricted to the range between 80 and 92 atomic per cent. The minimum value of ??? for a cerium-earth mineral corresponds to the smallest possible unit-cell size of the mineral. In monazite, this structurally controlled minimum value of ??? is estimated to be around 30 atomic per cent. Neodymium, because of its abundance, and yttrium, because of its small size, have dominant roles in contraction of the structure. In the other direction, the limit of variation in composition will be reached when lanthanum becomes the sole rare-earth element in a cerium-earth mineral. Cerium-earth minerals from alkalic rocks are all characterized by values of ??? greater than 80 atomic per cent, indicating that the processes that formed these rocks were unusually efficient in fractionating the rare-earth elements-efficient in the sense that a highly selected assemblage is produced without eliminating the bulk of these elements. Analyses of inner and outer parts of two large crystals of monazite from different deposits show no difference in ??? in one crystal and a slightly smaller value of ??? in the outer part of the other crystal compared to the inner part. The ??? of monazites from pegmatites that intrude genetically related granitic rocks in North Carolina is found to be either higher or lower than the ??? of monazites in the intruded host rock. These results indicate that the fractionation of the

  6. Alkali elements in the Earth's core: Evidence from enstatite meteorites

    NASA Technical Reports Server (NTRS)

    Lodders, K.

    1995-01-01

    The abundances of alkali elements in the Earth's core are predicted by assuming that accretion of the Earth started from material similar in composition to enstatite chondrites and that enstatite achondrites (aubrites) provide a natural laboratory to study core-mantle differentiation under extremely reducing conditions. If core formation on the aubrite parent body is comparable with core formation on the early Earth, it is found that 2600 (+/- 1000) ppm Na, 550 (+/- 260) ppm K, 3.4 (+/- 2.1) ppm Rb, and 0.31 (+/- 0.24) ppm Cs can reside in the Earth's core. The alkali-element abundances are consistent with those predicted by independent estimates based on nebula condensation calculations and heat flow data.

  7. Magnetic Nanofluid Rare Earth Element Extraction Process Report, Techno Economic Analysis, and Results for Geothermal Fluids

    DOE Data Explorer

    Pete McGrail

    2016-03-14

    This GDR submission is an interim technical report and raw data files from the first year of testing on functionalized nanoparticles for rare earth element extraction from geothermal fluids. The report contains Rare Earth Element uptake results (percent removal, mg Rare Earth Element/gram of sorbent, distribution coefficient) for the elements of Neodymium, Europium, Yttrium, Dysprosium, and Cesium. A detailed techno economic analysis is also presented in the report for a scaled up geothermal rare earth element extraction process. All rare earth element uptake testing was done on simulated geothermal brines with one rare earth element in each brine. The rare earth element uptake testing was conducted at room temperature.

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

    USGS Publications Warehouse

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

    1955-01-01

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

  9. Anthropogenic disturbance of element cycles at the Earth's surface.

    PubMed

    Sen, Indra S; Peucker-Ehrenbrink, Bernhard

    2012-08-21

    The extent to which humans are modifying Earth's surface chemistry can be quantified by comparing total anthropogenic element fluxes with their natural counterparts (Klee and Graedel, 2004). We quantify anthropogenic mass transfer of 77 elements from mining, fossil fuel burning, biomass burning, construction activities, and human apportionment of terrestrial net primary productivity, and compare it to natural mass transfer from terrestrial and marine net primary productivity, riverine dissolved and suspended matter fluxes to the ocean, soil erosion, eolian dust, sea-salt spray, cosmic dust, volcanic emissions, and for helium, hydrodynamic escape from the Earth's atmosphere. We introduce an approach to correct for losses during industrial processing of elements belonging to geochemically coherent groups, and explicitly incorporate uncertainties of element mass fluxes through Monte Carlo simulations. We find that at the Earth's surface anthropogenic fluxes of iridium, osmium, helium, gold, ruthenium, antimony, platinum, palladium, rhenium, rhodium and chromium currently exceed natural fluxes. For these elements mining is the major factor of anthropogenic influence, whereas petroleum burning strongly influences the surficial cycle of rhenium. Our assessment indicates that if anthropogenic contributions to soil erosion and eolian dust are considered, anthropogenic fluxes of up to 62 elements surpass their corresponding natural fluxes. PMID:22803636

  10. Multi-objective optimization of chromatographic rare earth element separation.

    PubMed

    Knutson, Hans-Kristian; Holmqvist, Anders; Nilsson, Bernt

    2015-10-16

    The importance of rare earth elements in modern technological industry grows, and as a result the interest for developing separation processes increases. This work is a part of developing chromatography as a rare earth element processing method. Process optimization is an important step in process development, and there are several competing objectives that need to be considered in a chromatographic separation process. Most studies are limited to evaluating the two competing objectives productivity and yield, and studies of scenarios with tri-objective optimizations are scarce. Tri-objective optimizations are much needed when evaluating the chromatographic separation of rare earth elements due to the importance of product pool concentration along with productivity and yield as process objectives. In this work, a multi-objective optimization strategy considering productivity, yield and pool concentration is proposed. This was carried out in the frame of a model based optimization study on a batch chromatography separation of the rare earth elements samarium, europium and gadolinium. The findings from the multi-objective optimization were used to provide with a general strategy for achieving desirable operation points, resulting in a productivity ranging between 0.61 and 0.75 kgEu/mcolumn(3), h(-1) and a pool concentration between 0.52 and 0.79 kgEu/m(3), while maintaining a purity above 99% and never falling below an 80% yield for the main target component europium. PMID:26375205

  11. Experimental constraints on light elements in the Earth's outer core.

    PubMed

    Zhang, Youjun; Sekine, Toshimori; He, Hongliang; Yu, Yin; Liu, Fusheng; Zhang, Mingjian

    2016-01-01

    Earth's outer core is liquid and dominantly composed of iron and nickel (~5-10 wt%). Its density, however, is ~8% lower than that of liquid iron, and requires the presence of a significant amount of light element(s). A good way to specify the light element(s) is a direct comparison of density and sound velocity measurements between seismological data and those of possible candidate compositions at the core conditions. We report the sound velocity measurements of a model core composition in the Fe-Ni-Si system at the outer core conditions by shock-wave experiments. Combining with the previous studies, we found that the best estimate for the outer core's light elements is ~6 wt% Si, ~2 wt% S, and possible ~1-2.5 wt% O. This composition satisfies the requirements imposed by seismology, geochemistry, and some models of the early core formation. This finding may help us to further constrain the thermal structure of the Earth and the models of Earth's core formation. PMID:26932596

  12. Coal fly ash as a resource for rare earth elements.

    PubMed

    Franus, Wojciech; Wiatros-Motyka, Małgorzata M; Wdowin, Magdalena

    2015-06-01

    Rare earth elements (REE) have been recognised as critical raw materials, crucial for many clean technologies. As the gap between their global demand and supply increases, the search for their alternative resources becomes more and more important, especially for the countries which depend highly on their import. Coal fly ash (CFA), which when not utilised is considered waste, has been regarded as the possible source of many elements, including REE. Due to the increase in the energy demand, CFA production is expected to grow, making research into the use of this material a necessity. As Poland is the second biggest coal consumer in the European Union, the authors have studied different coal fly ashes from ten Polish power plants for their rare earth element content. All the fly ashes have a broadly similar distribution of rear earth elements, with light REE being dominant. Most of the samples have REE content relatively high and according to Seredin and Dai (Int J Coal Geol 94: 67-93, 2012) classification can be considered promising REE raw materials. PMID:25613802

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Contamination in the Rare-Earth Element Orthophosphate Reference Samples

    PubMed Central

    Donovan, John J.; Hanchar, John M.; Picolli, Phillip M.; Schrier, Marc D.; Boatner, Lynn A.; Jarosewich, Eugene

    2002-01-01

    Several of the fourteen rare-earth element (plus Sc and Y) orthophosphate standards grown at Oak Ridge National Laboratory in the 1980s and widely distributed by the Smithsonian Institution’s Department of Mineral Sciences, are significantly contaminated by Pb. The origin of this impurity is the Pb2P2O7 flux that is derived from the thermal decomposition of PbHPO4. The lead pyrophosphate flux is used to dissolve the oxide starting materials at elevated temperatures (≈1360 °C) prior to the crystal synthesis. Because these rare-earth element standards are extremely stable under the electron beam and considered homogenous, they have been of enormous value to electron probe micro-analysis (EPMA). The monoclinic, monazite structure, orthophosphates show a higher degree of Pb incorporation than the tetragonal xenotime structure, orthophosphates. This paper will attempt to describe and rationalize the extent of the Pb contamination in these otherwise excellent materials.

  15. Uncovering the Global Life Cycles of the Rare Earth Elements

    PubMed Central

    Du, Xiaoyue; Graedel, T. E.

    2011-01-01

    The rare earth elements (REE) are a group of fifteen elements with unique properties that make them indispensable for a wide variety of emerging, critical technologies. Knowledge of the life cycles of REE remains sparse, despite the current heightened interest in their future availability. Mining is heavily concentrated in China, whose monopoly position and potential restriction of exports render primary supplies vulnerable to short and long-term disruption. To provide an improved perspective we derived the first quantitative life cycles (for the year 2007) for ten REE: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), and yttrium (Y). Of these REE, Ce and Nd in-use stocks are highest; the in-use stocks of most REE show significant accumulation in modern society. Industrial scrap recycling occurs only from magnet manufacture. We believe there is no post-customer recycling of any of these elements. PMID:22355662

  16. Anthropogenic Disturbance of Element Cycles at the Earth's Surface

    NASA Astrophysics Data System (ADS)

    Sen, I. S.; Peucker-Ehrenbrink, B.

    2012-12-01

    The extent to which humans are modifying Earth's surface chemistry can be quantified by comparing total anthropogenic element fluxes with their natural counterparts [1]. We determine anthropogenic mass transfer of 77 elements from mining, fossil fuel burning, biomass burning, construction activities, and human apportionment of terrestrial net primary productivity, and compared it to natural mass transfer from terrestrial and marine net primary productivity, riverine dissolved and suspended matter fluxes to the ocean, soil erosion, eolian dust, sea-salt spray, cosmic dust, volcanic emissions and - for helium - hydrodynamic escape from the Earth's atmosphere. In addition, we introduce an approach to correct for losses during industrial processing of elements belonging to geochemically coherent groups, and explicitly incorporated uncertainties of element mass fluxes through Monte Carlo simulations [2]. Our assessment indicates that anthropogenic fluxes of iridium, osmium, helium, gold, ruthenium, antimony, platinum, palladium, rhenium, rhodium and chromium are greater than the respective natural fluxes. For these elements mining is the major factor of human dominance, whereas petroleum burning strongly influence the surficial cycle of rhenium. Apart from these 11 elements there are 15 additional elements whose anthropogenic fluxes may surpass their corresponding natural fluxes. Anthropogenic fluxes of the remaining elements are smaller than their corresponding natural fluxes although a significant human influence is observed for all of them. For example, ~20% of the annual fluxes of C, N, and P can be attributed to human activities. Such disturbances, though small compared with natural fluxes, can significantly alter concentrations in near-surface reservoirs and affect ecosystems if they are sustained over time scales similar to or longer than the residence time of elements in the respective reservoir. Examples are the continuing input of CO2 to the atmosphere that

  17. The Earth Based Ground Stations Element of the Lunar Program

    NASA Technical Reports Server (NTRS)

    Gal-Edd, Jonathan; Fatig, Curtis; Schier, James; Lee, Charles

    2007-01-01

    The Lunar Architecture Team (LAT) is responsible for developing a concept for building and supporting a lunar outpost with several exploration capabilities such as rovers, colonization, and observatories. The lunar outpost is planned to be located at the Moon's South Pole. The LAT Communications and Navigation Team (C&N) is responsible for defining the network infrastructure to support the lunar outpost. The following elements are needed to support lunar outpost activities: A Lunar surface network based on industry standard wireless 802.xx protocols, relay satellites positioned 180 degrees apart to provide South Pole coverage for the half of the lunar 28-day orbit that is obscured from Earth view, earth-based ground stations deployed at geographical locations 120 degrees apart. This paper will focus on the Earth ground stations of the lunar architecture. Two types of ground station networks are discussed. One provides Direct to Earth (DTE) support to lunar users using Kaband 23/26Giga-Hertz (GHz) communication frequencies. The second supports the Lunar Relay Satellite (LRS) that will be using Ka-band 40/37GHz (Q-band). This paper will discuss strategies to provide a robust operational network in support of various lunar missions and trades of building new antennas at non-NASA facilities, to improve coverage and provide site diversification for handling rain attenuation.

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

    PubMed

    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

  19. Germanium and Rare Earth Element accumulation in woody bioenergy crops

    NASA Astrophysics Data System (ADS)

    Hentschel, Werner

    2016-04-01

    Germanium and REEs are strategic elements that are used for high tech devices and engineered systems, however these elements are hardly concentrated into mineable ore deposits. Since these elements occur widely dispersed in the earth crust with concentrations of several mgṡkg‑1 (Ge 1.6 mgṡkg‑1, Nd 25 mgṡkg‑1) a new possibility to gain these elements could be phytomining, a technique that uses plants to extract elements from soils via their roots. Since knowledge about accumulating plant species is quite limited we conducted research on the concentrations of strategic elements in wood and leaves of fast growing tree species (Salix spec., Populus spec., Betula pendula, Alnus glutinosa, Fraxinus excelsior, Acer pseudoplatanus). In total 35 study sites were selected in the mining affected area around Freiberg (Saxony, Germany), differing in their species composition and degree of contamination with toxic trace metals (Pb, As, Cd). On each site plant tissues (wood and leaves, respectively) of different species were sampled. In addition soil samples were taken from a soil depth of 0 - 30 cm and 30 - 60 cm. The aim of our work was to investigate correlations between the concentrations of the target elements in plant tissues and soil characteristics like pH, texture, nutrients and concentrations in six operationally defined soil fractions (mobile, acid soluble, oxidizable, amorphic oxides, crystalline oxides, residual or siliceous). Concentrations of elements in soil extracts and plant tissues were measured with ICP-MS. The element Nd was selected as representative for the group of REEs, since this element showed a high correlation with the concentrations of the other REE We found that the concentration of Nd in the leaves (0.31 mgṡkg‑1Nd) were several times higher than in herbaceous species (0.05 mgṡkg‑1 Nd). The concentration of Ge in leaves were ten times lower than that of Nd whereas in herbaceous species Nd and Ge were in equal magnitude. Within

  20. Rare earth element content of cryptocrystalline magnesites of Konya, Turkey

    NASA Astrophysics Data System (ADS)

    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.

  1. Compositional and phase relations among rare earth element minerals

    NASA Technical Reports Server (NTRS)

    Burt, D. M.

    1989-01-01

    A review is presented that mainly treats minerals in which the rare-earth elements are essential constituents, e.g., bastnaesite, monazite, xenotime, aeschynite, allanite. The chemical mechanisms and limits of REE substitution in some rock-forming minerals (zircon, apatite, titanite, garnet) are also derived. Vector representation of complex coupled substitutions in selected REE-bearing minerals is examined and some comments on REE-partitioning between minerals as related to acid-based tendencies and mineral stabilities are presented. As the same or analogous coupled substitutions involving the REE occur in a wide variety of mineral structures, they are discussed together.

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

    SciTech Connect

    Laul, J.C.; Lepel, E.A.

    1986-04-21

    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/sup -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.

  3. Standard reference water samples for rare earth element determinations

    USGS Publications Warehouse

    Verplanck, P.L.; Antweiler, R.C.; Nordstrom, D.K.; Taylor, H.E.

    2001-01-01

    Standard reference water samples (SRWS) were collected from two mine sites, one near Ophir, CO, USA and the other near Redding, CA, USA. The samples were filtered, preserved, and analyzed for rare earth element (REE) concentrations (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) by inductively coupled plasma-mass spectrometry (ICP-MS). These two samples were acid mine waters with elevated concentrations of REEs (0.45-161 ??g/1). Seventeen international laboratories participated in a 'round-robin' chemical analysis program, which made it possible to evaluate the data by robust statistical procedures that are insensitive to outliers. The resulting most probable values are reported. Ten to 15 of the participants also reported values for Ba, Y, and Sc. Field parameters, major ion, and other trace element concentrations, not subject to statistical evaluation, are provided.

  4. Mimicking the magnetic properties of rare earth elements using superatoms

    PubMed Central

    Cheng, Shi-Bo; Berkdemir, Cuneyt; Castleman, A. W.

    2015-01-01

    Rare earth elements (REs) consist of a very important group in the periodic table that is vital to many modern technologies. The mining process, however, is extremely damaging to the environment, making them low yield and very expensive. Therefore, mimicking the properties of REs in a superatom framework is especially valuable but at the same time, technically challenging and requiring advanced concepts about manipulating properties of atom/molecular complexes. Herein, by using photoelectron imaging spectroscopy, we provide original idea and direct experimental evidence that chosen boron-doped clusters could mimic the magnetic characteristics of REs. Specifically, the neutral LaB and NdB clusters are found to have similar unpaired electrons and magnetic moments as their isovalent REs (namely Nd and Eu, respectively), opening up the great possibility in accomplishing rare earth mimicry. Extension of the superatom concept into the rare earth group not only further shows the power and advance of this concept but also, will stimulate more efforts to explore new superatomic clusters to mimic the chemistry of these heavy atoms, which will be of great importance in designing novel building blocks in the application of cluster-assembled nanomaterials. Additionally, based on these experimental findings, a novel “magic boron” counting rule is proposed to estimate the numbers of unpaired electrons in diatomic LnB clusters. PMID:25848014

  5. Mimicking the magnetic properties of rare earth elements using superatoms.

    PubMed

    Cheng, Shi-Bo; Berkdemir, Cuneyt; Castleman, A W

    2015-04-21

    Rare earth elements (REs) consist of a very important group in the periodic table that is vital to many modern technologies. The mining process, however, is extremely damaging to the environment, making them low yield and very expensive. Therefore, mimicking the properties of REs in a superatom framework is especially valuable but at the same time, technically challenging and requiring advanced concepts about manipulating properties of atom/molecular complexes. Herein, by using photoelectron imaging spectroscopy, we provide original idea and direct experimental evidence that chosen boron-doped clusters could mimic the magnetic characteristics of REs. Specifically, the neutral LaB and NdB clusters are found to have similar unpaired electrons and magnetic moments as their isovalent REs (namely Nd and Eu, respectively), opening up the great possibility in accomplishing rare earth mimicry. Extension of the superatom concept into the rare earth group not only further shows the power and advance of this concept but also, will stimulate more efforts to explore new superatomic clusters to mimic the chemistry of these heavy atoms, which will be of great importance in designing novel building blocks in the application of cluster-assembled nanomaterials. Additionally, based on these experimental findings, a novel "magic boron" counting rule is proposed to estimate the numbers of unpaired electrons in diatomic LnB clusters. PMID:25848014

  6. Bacterial Cell Surface Adsorption of Rare Earth Elements

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  7. Trace elemental imaging of rare earth elements discriminates tissues at microscale in flat fossils.

    PubMed

    Gueriau, Pierre; Mocuta, Cristian; Dutheil, Didier B; Cohen, Serge X; Thiaudière, Dominique; Charbonnier, Sylvain; Clément, Gaël; Bertrand, Loïc

    2014-01-01

    The interpretation of flattened fossils remains a major challenge due to compression of their complex anatomies during fossilization, making critical anatomical features invisible or hardly discernible. Key features are often hidden under greatly preserved decay prone tissues, or an unpreparable sedimentary matrix. A method offering access to such anatomical features is of paramount interest to resolve taxonomic affinities and to study fossils after a least possible invasive preparation. Unfortunately, the widely-used X-ray micro-computed tomography, for visualizing hidden or internal structures of a broad range of fossils, is generally inapplicable to flattened specimens, due to the very high differential absorbance in distinct directions. Here we show that synchrotron X-ray fluorescence spectral raster-scanning coupled to spectral decomposition or a much faster Kullback-Leibler divergence based statistical analysis provides microscale visualization of tissues. We imaged exceptionally well-preserved fossils from the Late Cretaceous without needing any prior delicate preparation. The contrasting elemental distributions greatly improved the discrimination of skeletal elements material from both the sedimentary matrix and fossilized soft tissues. Aside content in alkaline earth elements and phosphorus, a critical parameter for tissue discrimination is the distinct amounts of rare earth elements. Local quantification of rare earths may open new avenues for fossil description but also in paleoenvironmental and taphonomical studies. PMID:24489809

  8. Trace Elemental Imaging of Rare Earth Elements Discriminates Tissues at Microscale in Flat Fossils

    PubMed Central

    Gueriau, Pierre; Mocuta, Cristian; Dutheil, Didier B.; Cohen, Serge X.; Thiaudière, Dominique; Charbonnier, Sylvain; Clément, Gaël; Bertrand, Loïc

    2014-01-01

    The interpretation of flattened fossils remains a major challenge due to compression of their complex anatomies during fossilization, making critical anatomical features invisible or hardly discernible. Key features are often hidden under greatly preserved decay prone tissues, or an unpreparable sedimentary matrix. A method offering access to such anatomical features is of paramount interest to resolve taxonomic affinities and to study fossils after a least possible invasive preparation. Unfortunately, the widely-used X-ray micro-computed tomography, for visualizing hidden or internal structures of a broad range of fossils, is generally inapplicable to flattened specimens, due to the very high differential absorbance in distinct directions. Here we show that synchrotron X-ray fluorescence spectral raster-scanning coupled to spectral decomposition or a much faster Kullback-Leibler divergence based statistical analysis provides microscale visualization of tissues. We imaged exceptionally well-preserved fossils from the Late Cretaceous without needing any prior delicate preparation. The contrasting elemental distributions greatly improved the discrimination of skeletal elements material from both the sedimentary matrix and fossilized soft tissues. Aside content in alkaline earth elements and phosphorus, a critical parameter for tissue discrimination is the distinct amounts of rare earth elements. Local quantification of rare earths may open new avenues for fossil description but also in paleoenvironmental and taphonomical studies. PMID:24489809

  9. The elements of the Earth's magnetism and their secular changes between 1550 and 1915

    NASA Technical Reports Server (NTRS)

    Fritsche, H.

    1983-01-01

    The results of an investigation about the magnetic agents outside the Earth's surface as well as the Earth's magnetic elements for the epochs 1550, 1900, 1915 are presented. The secular changes of the Earth's magnetic elements during the time interval 1550 - 1900 are also included.

  10. Core-Mantle Partitioning of Volatile Elements and the Origin of Volatile Elements in Earth and Moon

    NASA Technical Reports Server (NTRS)

    Righter, K.; Pando, K.; Danielson, L.; Nickodem, K.

    2014-01-01

    Depletions of siderophile elements in mantles have placed constraints on the conditions on core segregation and differentiation in bodies such as Earth, Earth's Moon, Mars, and asteroid 4 Vesta. Among the siderophile elements there are a sub-set that are also volatile (volatile siderophile elements or VSE; Ga, Ge, In, As, Sb, Sn, Bi, Zn, Cu, Cd), and thus can help to constrain the origin of volatile elements in these bodies, and in particular the Earth and Moon. One of the fundamental observations of the geochemistry of the Moon is the overall depletion of volatile elements relative to the Earth, but a satisfactory explanation has remained elusive. Hypotheses for Earth include addition during accretion and core formation and mobilized into the metallic core, multiple stage origin, or addition after the core formed. Any explanation for volatile elements in the Earth's mantle must also be linked to an explanation of these elements in the lunar mantle. New metal-silicate partitioning data will be applied to the origin of volatile elements in both the Earth and Moon, and will evaluate theories for exogenous versus endogenous origin of volatile elements.

  11. Elemental processes of transport and energy conversion in Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Angelopoulos, Vassilis

    In the last 5 years observations from several missions and ground based observatories have honed in on the most elemental aspects of flux transport and energy conversion. Dipolarization fronts and their counterpart in the distant magnetotail "anti-dipolarization" fronts, which together are refered to herein as "reconnection fronts", usher the recently reconnected flux tubes from the near-Earth X-points and in the process convert magnetic energy to particle energy and wave radiation. On the tailward side they are responsible for plasmoid formation and acceleration. On the earthward side they result in elemental substorm current wedges or wedglets, which were initially postulated from ground observations alone. Recent observations have revealed how the interaction of wedgelets and the inner magnetosphere takes place. Questions remain with regards to the physics of the energy transfer process from global magnetic energy to local heating and waves, and with regards to the initiation of the X-point activations in space. Observations indicate that the latter may be induced by polar cap or dayside activity, suggesting a direct link between dayside reconnection and nightside phenomena. The likely causal sequence of events and open questions in light of these recent observations, and the field's outlook in anticipation of upcoming coordinated observations from the international Heliophysics System Observatory will be discussed.

  12. Reducing the detection limits of rare earth elements in steels

    SciTech Connect

    Raskevich, V.K.; Maiboroda, I.K.; Frishberg, A.A.; Panfilova, S.Ya.

    1986-12-01

    Chemical and chemicospectral analysis methods make it possible to determine rare-earth elements (REE) reliably in steels, but they are time-consuming and laborious. X-ray fluorescence methods are also characterized by the complicated procedure of preparing standard and production specimens for analysis. In this paper, the authors attempt to develop a spectrographic method of determining the REEs in the steel using standard equipment. The authors prepare synthetic standard specimens for determining Ce, Nd, La, Pr, and Y in steels of various grades by adding titrated solutions of the salts of the determined elements to the powder of the steel without REE with subsequent evaporation, drying, and mixing. The steels were ground by the mechanical method. On the basis of the resulting detection limits and analysis accuracy, the proposed method can be recommended for inspection of the technological process in melting steels and for preparation of standard specimens in the plant. The method is 5-7 times faster than the chemicospectral method.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  15. Isotopic fractionation of rare earth elements in geochemical samples

    NASA Astrophysics Data System (ADS)

    Ishibashi, T.; Ohno, T.

    2015-12-01

    The isotopic composition of Rare Earth Elements(REEs) can be fractionated through various physical and chemical reactions in nature [1]. The isotopic variations of REEs occurring naturally has a potentially significant influence in geochemical research fields. The REEs has key features that their chemical similarities and gradual changes of ionic radius, which may help us to understand the mechanisms of isotopic variations of REEs in nature. Among the REEs, geochemical and physicochemical features of Ce, which could be presence as the tetravalent state, be anomalous, and oxidation state of Ce can change by reflecting the redox conditions of the environment. Therefore, the study of the difference in the degree of isotopic fractionation between Ce and other REEs may provide information on the redox conditions. In this study, we developed a new separation method to determine the mass-dependent isotopic fractionations of REEs in geochemical samples, and examined the optimum concentration of hydrochloric acid for the separation. The samples were decomposed by a mixture of acids, then REEs were separated as a group from major elements using cation exchange resin columns and RE Spec resin. The separations within the REEs group were carried out using Ln2Spec resin. For the recovery of La, Ce, Pr, and Nd, 0.1 M HCl was used, and for isolation of Sm, Eu, and Gd, 0.25 M HCl was used. Then, 0.6 M HCl was used for separation of Tb, and Dy, 1 M HCl was used for separation of Ho, Y, and Er, finally, Tm, Yb, and Lu were collected using 2 M HCl. The yields of all REEs were enough to examine isotopic fractionation in geochemical samples. [1] Ohno and Hirata,Analytical Sciences, 29, 271, 2013

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

    NASA Technical Reports Server (NTRS)

    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.

  17. Geochemical behavior of rare earth elements and other trace elements in the Amazon River

    NASA Astrophysics Data System (ADS)

    Merschel, Gila; Bau, Michael; Dantas, Elton Luiz

    2014-05-01

    Rivers transport large amounts of dissolved and suspended particulate material from the catchment area to the oceans and are a major source of trace metals to seawater. The Amazon River is the world's largest river and supplies approximately 20% of the oceans' freshwater (Molinier et al., 1997). However, the behavior of trace elements, especially particle-reactive elements such as the rare earth elements (REE), within the river as well as in the estuary is not well constrained and rather little is known about their transport mechanisms. This study aims at understanding the transport properties of particle-reactive elements in the Amazon River and some of its major tributaries, including the Rio Solimões, Rio Negro, Tapajos, Xingu and Jari Rivers. Samples were taken at 12 stations, seven of which were located in the Amazon mainstream, while the other five stations sampled its tributaries. To account for the effects of variable discharge, the samples were collected during periods of high and low discharge. We present data for major and trace elements, including REE, of the dissolved and suspended load of these samples. First results indicate that the shale-normalized REE pattern of the dissolved load (filtered through 0.2 µm membranes) of the Amazon mainstream and the Rio Solimões confirm earlier studies (Elderfield et al., 1990; Gerard et al., 2003) and show an enrichment of the middle REE relative to the light and heavy REE (LaSN/GdSN: 0.25 - 0.32; GdSN/YbSN: 1.54 - 1.78). In contrast to the Amazon mainstream and the Rio Solimões, which are considered to be whitewater rivers, blackwater rivers, such as the Rio Negro, have a flat REE pattern with higher REE concentrations than whitewater rivers. The third water-type found in the Amazon Basin is clearwater, e.g. Rio Tapajos, with REE patterns in between those of the other two types, i.e. LaSN/GdSN: 0.55 - 0.70; GdSN/YbSN: 1.26 - 1.55. A similar behavior can be identified for other major and trace elements. While

  18. Effects of spraying rare earths on contents of rare Earth elements and effective components in tea.

    PubMed

    Wang, Dongfeng; Wang, Changhong; Ye, Sheng; Qi, Hongtao; Zhao, Guiwen

    2003-11-01

    Rare earth (RE) fertilizer is widely applied in China to increase the yield and the quality of crops including tea. However, the effects of spraying RE fertilizer on the contents of rare earth elements (REE) and effective components in tea are unknown. The results from basin and field experiments show that the values of the REE concentrations in new shoots of tea plants and the concentration of REE in the soil (REE/REEs) either from control basins or from treatment basins were smaller than those in other parts of tea plant and similar between control and treatment. The longer the interval between spraying RE fertilizer and picking the shoots of tea plants, the less the effects from spraying. About 80% summation operator REE (the sum of the concentrations of 15 REE) in tea, whether it came from spraying or not, was insoluble in the infusion. About 10% the soluble REE of summation operator REE in tea infusion was bound to polysaccharide, and the amount of REE bound polysaccharide decreased over time. At least a 25 day safety interval is needed between spraying and picking if the microelement fertilizer is used, in order to enhance tea output and to ensure tea safety. PMID:14582968

  19. Rare-earth element based permanent magnets: a theoretical investigation

    NASA Astrophysics Data System (ADS)

    Chouhan, Rajiv K.; Paudyal, Durga

    Permanent magnetic materials with large magnetization and high magnetocrystalline anisotropy are important for technical applications. In this context rare-earth (R) element based materials are good candidates because of their localized 4 f electrons. The 4 f crystal field splitting provides large part of magnetic anisotropy depending upon the crystal environment. The d spin orbit coupling of alloyed transition metal component provides additional anisotropy. RCo5 and its derivative R2Co17 are known compounds for large magnetic anisotropy. Here we have performed electronic structure calculations to predict new materials in this class by employing site substitutions. In these investigations, we have performed density functional theory including on-site electron correlation (DFT +U) and L-S coupling calculations. The results show that the abundant Ce substitution in R sites and Ti/Zr substitutions in some of the Co sites help reduce criticality without substantially affecting the magnetic moment and magnetic anisotropy in these materials. This work is supported by the Critical Materials Institute, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office.

  20. Size distribution of rare earth elements in coal ash

    USGS Publications Warehouse

    Scott, Clinton T.; Deonarine, Amrika; Kolker, Allan; Adams, Monique; Holland, James F.

    2015-01-01

    Rare earth elements (REEs) are utilized in various applications that are vital to the automotive, petrochemical, medical, and information technology industries. As world demand for REEs increases, critical shortages are expected. Due to the retention of REEs during coal combustion, coal fly ash is increasingly considered a potential resource. Previous studies have demonstrated that coal fly ash is variably enriched in REEs relative to feed coal (e.g, Seredin and Dai, 2012) and that enrichment increases with decreasing size fractions (Blissett et al., 2014). In order to further explore the REE resource potential of coal ash, and determine the partitioning behavior of REE as a function of grain size, we studied whole coal and fly ash size-fractions collected from three U.S commercial-scale coal-fired generating stations burning Appalachian or Powder River Basin coal. Whole fly ash was separated into , 5 um, to 5 to 10 um and 10 to 100 um particle size fractions by mechanical shaking using trace-metal clean procedures. In these samples REE enrichments in whole fly ash ranges 5.6 to 18.5 times that of feedcoals. Partitioning results for size separates relative to whole coal and whole fly ash will also be reported. 

  1. Investigating Rare Earth Element Systematics in the Marcellus Shale

    NASA Astrophysics Data System (ADS)

    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

  2. Attenuation of rare earth elements in a boreal estuary

    NASA Astrophysics Data System (ADS)

    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 < 6‰). Surface water was collected in a transect from the creek mouth to the outer estuary, and settling (particulate) material in sediment traps moored at selected locations in the estuary. Ultrafiltration, high-resolution ICP-MS and modeling were applied on the waters, and a variety of chemical reagents were used to 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 <1 kDa pool became depleted in the middle REE and the colloidal (0.45 μm-1 kDa) pool depleted in the middle and heavy REE. This fractionation was controlled by the removal process, such that those REE with highest affinity for the settling particles became most depleted in the remaining dissolved pool. Modeling, based on Visual MINTEQ version 3.0 and the Stockholm Humic Model after revision and updating, predicted that the dissolved (<0.45 μm) REE pool in the estuary is bound almost entirely to humic substances. Acid sulphate soils, the source of the REE and other metals in the creek water, are widespread on coastal plains worldwide and therefore the REE attenuation patterns and mechanisms identified in the studied estuary are relevant for recognition of similar geochemical processes and conditions in a variety of coastal locations.

  3. Recovery and Separation of Rare Earth Elements Using Salmon Milt

    PubMed Central

    Takahashi, Yoshio; Kondo, Kazuhiro; Miyaji, Asami; Watanabe, Yusuke; Fan, Qiaohui; Honma, Tetsuo; Tanaka, Kazuya

    2014-01-01

    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. PMID:25490035

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

    USGS Publications Warehouse

    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.

  5. Miocene Coral Skeleton Rare Earth Element Patterns Reflect River Discharge

    NASA Astrophysics Data System (ADS)

    Mertz-Kraus, R.; Brachert, T. C.; Jochum, K. P.

    2010-12-01

    Rare Earth Element (REE) patterns of modern coral skeletons usually reflect the REE composition of ambient seawater which is characterized by heavy REE enriched relative to light REE with NASC (North American Shale Composite) normalized La/Lu ratios of typically <0.4. The REE concentration in coral aragonite is enriched by 3 to 4 orders of magnitude compared to ambient seawater. Here we report trace element data including REE of coral skeletons of Late Miocene age (~9 Ma, Tortonian) from Crete (Eastern Mediterranean). Analyses were done using a 213 nm Nd:YAG laser coupled to an Element2 ICP-MS along the growth axis of the coral skeletons. The profiles show that Ba/Ca ratios have a seasonally induced pattern with high values around the winter months which are identified by δ18O analyses. REE/Ca ratios co-vary with Ba/Ca ratios. Since the Ba/Ca ratio is a proxy used to monitor river discharge, the co-variation suggests the REE/Ca ratio to be a proxy of comparable quality. NASC-normalized REE patterns of the Tortonian corals have negative Ce anomalies like modern corals. However, the Tortonian corals have REE patterns highly enriched in LREE with (La/Lu)N ratios of 4 to 30 which is 1 to 2 orders of magnitude higher compared to modern corals. Al concentrations are low (<10 ppm) and do not correlate with REE concentrations indicating an insignificant fraction of terrigenous material included in the skeleton. Applying distribution coefficients typical for modern corals, the REE composition of the Tortonian ambient water yields (La/Lu)N of about 2 to 16. This range can be explained by binary mixing of modern Eastern Mediterranean sea surface water ((La/Lu)N=0.35, sea surface salinity (SSS) ~38 ‰) with highly LREE-enriched river water ((La/Lu)N >3, salinity ~0.5 ‰) transporting suspended and colloid phases, also highly enriched, especially in LREE, at a ratio of ~9 (seawater):1 (river water). The river water component is considered because paleoenvironmental

  6. PROCESS FOR SEPARATING AMERICIUM AND CURIUM FROM RARE EARTH ELEMENTS

    DOEpatents

    Baybarz, R.D.; Lloyd, M.H.

    1963-02-26

    This invention relates to methods of separating americium and curium values from rare earth values. In accordance with the invention americium, curium, and rare earth values are sorbed on an anion exchange resin. A major portion of the rare earth values are selectively stripped from the resin with a concentrated aqueous solution of lithium chloride, and americium, curium, and a minor portion of rare earth values are then stripped from the resin with a dilute aqueous solution of lithium chloride. The americium and curium values are further purified by increasing the concentration of lithium chloride in the solution to at least 8 molar and selectively extracting rare earth values from the resulting solution with a monoalkylphosphoric acid. (AEC)

  7. Core-Mantle Partitioning of Volatile Siderophile Elements and the Origin of Volatile Elements in the Earth

    NASA Technical Reports Server (NTRS)

    Nickodem, K.; Righter, K.; Danielson, L.; Pando, K.; Lee, C.

    2012-01-01

    There are currently several hypotheses on the origin of volatile siderophile elements in the Earth. One hypothesis is that they were added during Earth s accretion and core formation and mobilized into the metallic core [1], others claim multiple stage origin [2], while some hypothesize that volatiles were added after the core already formed [3]. Several volatile siderophile elements are depleted in Earth s mantle relative to the chondrites, something which continues to puzzle many scientists. This depletion is likely due to a combination of volatility and core formation. The Earth s core is composed of Fe and some lighter constituents, although the abundances of these lighter elements are unknown [4]. Si is one of these potential light elements [5] although few studies have analyzed the effect of Si on metal-silicate partitioning, in particular the volatile elements. As, In, Ge, and Sb are trace volatile siderophile elements which are depleted in the mantle but have yet to be extensively studied. The metal-silicate partition coefficients of these elements will be measured to determine the effect of Si. Partition coefficients depend on temperature, pressure, oxygen fugacity, and metal and silicate composition and can constrain the concentrations of volatile, siderophile elements found in the mantle. Reported here are the results from 13 experiments examining the partitioning of As, In, Ge, and Sb between metallic and silicate liquid. These experiments will examine the effect of temperature, and metal-composition (i.e., Si content) on these elements in or-der to gain a greater understanding of the core-mantle separation which occurred during the Earth s early stages. The data can then be applied to the origin of volatile elements in the Earth.

  8. Rare Earth elements as sediment tracers in Mangrove ecosystems

    NASA Astrophysics Data System (ADS)

    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

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

    USGS Publications Warehouse

    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.

  10. Earth's moderately volatile element composition may not be chondritic: Evidence from In, Cd and Zn

    NASA Astrophysics Data System (ADS)

    Wang, Zaicong; Laurenz, Vera; Petitgirard, Sylvain; Becker, Harry

    2016-02-01

    Current models assume that siderophile volatile elements (SVE) are depleted in bulk Earth to the same extent as lithophile elements of similar volatility. The observed additional depletion of many SVE relative to lithophile elements in the bulk silicate Earth (BSE) is ascribed to partitioning of SVE into Earth's core. However, the assumption of similar volatility of moderately volatile elements during Earth formation processes as in solar gas is quite uncertain. Here, these assumptions will be tested by assessing abundances and ratios of indium and cadmium in the BSE using new data on mantle rocks, and the application of high- and low-pressure-temperature metal-silicate partitioning data. New bulk rock abundance data of In and Cd obtained on bulk rocks of peridotite tectonites and xenoliths by isotope dilution refine previous results inferred from basalts and in-situ analyses of silicate minerals in peridotite xenoliths. The CI chondrite-normalized abundance of In in the BSE is similar to zinc and is 3-4 times higher than Cd. New and published low- and high-P-T metal-silicate partitioning data indicate that, during core formation at a range of conditions, In is always more siderophile than Zn and Cd. Adding the fraction of these elements in Earth's core to the BSE results in bulk Earth compositions that yield higher CI chondrite normalized abundances of In in the bulk Earth compared to Zn and Cd. Because In is more volatile than Zn and Cd in gas of solar composition, suprachondritic In/Zn and In/Cd in the bulk Earth suggest that during formation of Earth or its building materials, the volatilities of these elements and perhaps other volatile elements likely have changed significantly (i.e. In became less volatile). The results also suggest that known carbonaceous chondrites likely did not deliver the main volatile element-rich fraction of the Earth. Various arguments suggest that the loss of moderately volatile elements during planetary accretion should be limited

  11. RARE EARTH ELEMENTS: A REVIEW OF PRODUCTION, PROCESSING, RECYCLING, AND ASSOCIATED ENVIRONMENTAL ISSUES

    EPA Science Inventory

    Rare earth elements (REEs) are a group of 15 chemical elements in the periodic table, specifically the lanthanides. Two other elements, scandium and yttrium, have a similar physiochemistry to the lanthanides, are commonly found in the same mineral assemblages, and are often refe...

  12. Rare Earth Elements: A Tool for Understanding the Behaviour of Trivalent Actinides in the Geosphere

    SciTech Connect

    Buil, Belen; Gomez, Paloma; Garralon, Antonio; Turrero, M. Jesus

    2007-07-01

    Rare earth element (REE) concentrations have been determined in groundwaters, granite and fracture fillings in a restored uranium mine. The granitoids normalized REE patterns of groundwaters show heavy rare earth elements (HREE)-enrichment and positive Eu anomalies. This suggests that the REE are fractionated during leaching from the source rocks by groundwaters. Preferential leaching of HREE would be consistent with the greater stability of their aqueous complexes compared to those of the light rare earth elements (LREE), together with the dissolution of certain fracture filling minerals, dissolution/alteration of phyllosilicates and colloidal transport. (authors)

  13. Rare earth elements and neodymium isotopes in sedimentary organic matter

    NASA Astrophysics Data System (ADS)

    Freslon, Nicolas; Bayon, Germain; Toucanne, Samuel; Bermell, Sylvain; Bollinger, Claire; Chéron, Sandrine; Etoubleau, Joel; Germain, Yoan; Khripounoff, Alexis; Ponzevera, Emmanuel; Rouget, Marie-Laure

    2014-09-01

    We report rare earth element (REE) and neodymium (Nd) isotope data for the organic fraction of sediments collected from various depositional environments, i.e. rivers (n = 25), estuaries (n = 18), open-ocean settings (n = 15), and cold seeps (n = 12). Sedimentary organic matter (SOM) was extracted using a mixed hydrogen peroxide/nitric acid solution (20%-H2O2-0.02 M-HNO3), after removal of carbonate and oxy-hydroxide phases with dilute hydrochloric acid (0.25 M-HCl). A series of experimental tests indicate that extraction of sedimentary organic compounds using H2O2 may be complicated occasionally by partial dissolution of sulphide minerals and residual carbonates. However, this contamination is expected to be minor for REE because measured concentrations in H2O2 leachates are about two-orders of magnitude higher than in the above mentioned phases. The mean REE concentrations determined in the H2O2 leachates for samples from rivers, estuaries, coastal seas and open-ocean settings yield relatively similar levels, with ΣREE = 109 ± 86 ppm (mean ± s; n = 58). The organic fractions leached from cold seep sediments display even higher concentration levels (285 ± 150 ppm; mean ± s; n = 12). The H2O2 leachates for most sediments exhibit remarkably similar shale-normalized REE patterns, all characterized by a mid-REE enrichment compared to the other REE. This suggests that the distribution of REE in leached sedimentary organic phases is controlled primarily by biogeochemical processes, rather than by the composition of the source from which they derive (e.g. pore, river or sea-water). The Nd isotopic compositions for organic phases leached from river sediments are very similar to those for the corresponding detrital fractions. In contrast, the SOM extracted from marine sediments display εNd values that typically range between the εNd signatures for terrestrial organic matter (inferred from the analysis of the sedimentary detrital fractions) and marine organic matter

  14. Rare Earth Element Partition Coefficients from Enstatite/Melt Synthesis Experiments

    NASA Technical Reports Server (NTRS)

    Schwandt, Craig S.; McKay, Gordon A.

    1997-01-01

    Enstatite (En(80)Fs(19)Wo(01)) was synthesized from a hypersthene normative basaltic melt doped at the same time with La, Ce, Nd, Sm, Eu, Dy, Er, Yb and Lu. The rare earth element concentrations were measured in both the basaltic glass and the enstatite. Rare earth element concentrations in the glass were determined by electron microprobe analysis with uncertainties less than two percent relative. Rare earth element concentrations in enstatite were determined by secondary ion mass spectrometry with uncertainties less than five percent relative. The resulting rare earth element partition signature for enstatite is similar to previous calculated and composite low-Ca pigeonite signatures, but is better defined and differs in several details. The partition coefficients are consistent with crystal structural constraints.

  15. Core-Mantle Partitioning of Volatile Elements and the Origin of Volatile Elements in Earth and Moon

    NASA Technical Reports Server (NTRS)

    Righter, Kevin; Pando, K.; Danielson, L.; Nickodem, K.

    2014-01-01

    Depletions of volatile siderophile elements (VSE; Ga, Ge, In, As, Sb, Sn, Bi, Zn, Cu, Cd) in mantles of Earth and Moon, constrain the origin of volatile elements in these bodies, and the overall depletion of volatile elements in Moon relative to Earth. A satisfactory explanation has remained elusive [1,2]. We examine the depletions of VSE in Earth and Moon and quantify the amount of depletion due to core formation and volatility of potential building blocks. We calculate the composition of the Earth's PUM during continuous accretion scenarios with constant and variable fO2. Results suggest that the VSE can be explained by a rather simple scenario of continuous accretion leading to a high PT metal-silicate equilibrium scenario that establishes the siderophile element content of Earth's PUM near the end of accretion [3]. Core formation models for the Moon explain most VSE, but calculated contents of In, Sn, and Zn (all with Tc < 750 K) are all still too high after core formation, and must therefore require an additional process to explain the depletions in the lunar mantle. We discuss possible processes including magmatic degassing, evaporation, condensation, and vapor-liquid fractionation in the lunar disk.

  16. Fluorescent lifetime measurements of rare-earth elements in gallium arsenide. Master's thesis

    SciTech Connect

    Topp, D.J.

    1990-12-01

    Lifetime measurements of the excited states of three GaAs semiconductors doped with the rare earth elements Erbium (Er), Praseodymium (Pr), and Thulium (Tm) has been studied using a pulsed nitrogen laser and germanium detector. The measurements were made with an experimental set up with a system response time of 0.34 microseconds. A 330 milliwatt nitrogen laser with a wavelength of 3370 angstroms was used to excite transitions of the rare earth elements.

  17. Experimental Parameters Affecting Stripping of Rare Earth Elements from Loaded Sorptive Media in Simulated Geothermal Brines

    DOE Data Explorer

    Dean Stull

    2016-05-24

    Experimental results from several studies exploring the impact of pH and acid volume on the stripping of rare earth elements (REEs) loaded onto ligand-based media via an active column. The REEs in this experiment were loaded onto the media through exposure to a simulated geothermal brine with known mineral concentrations. The data include the experiment results, rare earth element concentrations, and the experimental parameters varied.

  18. SEPARATION OF TRANSURANIC ELEMENTS FROM RARE EARTH COMPOUNDS

    DOEpatents

    Kohman, T.P.

    1961-11-21

    A process of separating neptunium and plutonium values from rare earths and alkaline earth fission products present on a solid mixed actinide carrier (Th or U(IV) oxalate or fluoride) --fission product carrier (LaF/sub 3/, CeF/sub 3/, SrF/sub 2/, CaF/sub 2/, YF/sub 3/, La oxalate, cerous oxalate, Sr oxalate, Ca oxalate or Y oxalate) by extraction of the actinides at elevated temperature with a solution of ammonium fluoride and/or ammonium oxalate is described. Separation of the fission-product-containing carriers from the actinide solution formed and precipitation of the neptunium and plutonium from the solution with mineral acid are also accomplished. (AEC)

  19. Rare earth element recycling from waste nickel-metal hydride batteries.

    PubMed

    Yang, Xiuli; Zhang, Junwei; Fang, Xihui

    2014-08-30

    With an increase in number of waste nickel-metal hydride batteries, and because of the importance of rare earth elements, the recycling of rare earth elements is becoming increasingly important. In this paper, we investigate the effects of temperature, hydrochloric acid concentration, and leaching time to optimize leaching conditions and determine leach kinetics. The results indicate that an increase in temperature, hydrochloric acid concentration, and leaching time enhance the leaching rate of rare earth elements. A maximum rare earth elements recovery of 95.16% was achieved at optimal leaching conditions of 70°C, solid/liquid ratio of 1:10, 20% hydrochloric acid concentration, -74μm particle size, and 100min leaching time. The experimental data were best fitted by a chemical reaction-controlled model. The activation energy was 43.98kJ/mol and the reaction order for hydrochloric acid concentration was 0.64. The kinetic equation for the leaching process was found to be: 1-(1-x)(1/3)=A/ρr0[HCl](0.64)exp-439,8008.314Tt. After leaching and filtration, by adding saturated oxalic solution to the filtrate, rare earth element oxalates were obtained. After removing impurities by adding ammonia, filtering, washing with dilute hydrochloric acid, and calcining at 810°C, a final product of 99% pure rare earth oxides was obtained. PMID:25089667

  20. Experimental productivity rate optimization of rare earth element separation through preparative solid phase extraction chromatography.

    PubMed

    Knutson, Hans-Kristian; Max-Hansen, Mark; Jönsson, Christian; Borg, Niklas; Nilsson, Bernt

    2014-06-27

    Separating individual rare earth elements from a complex mixture with several elements is difficult and this is emphasized for the middle elements: Samarium, Europium and Gadolinium. In this study we have accomplished an overloaded one-step separation of these rare earth elements through preparative ion-exchange high-performance liquid chromatography with an bis (2-ethylhexyl) phosphoric acid impregnated column and nitric acid as eluent. An inductively coupled plasma mass spectrometry unit was used for post column element detection. The main focus was to optimize the productivity rate, subject to a yield requirement of 80% and a purity requirement of 99% for each element, by varying the flow rate and batch load size. The optimal productivity rate in this study was 1.32kgSamarium/(hmcolumn(3)), 0.38kgEuropium/(hmcolumn(3)) and 0.81kgGadolinium/(hmcolumn(3)). PMID:24835593

  1. Vanadium oxide bronzes containing rare-earth elements

    SciTech Connect

    Volkov, V.L.; Zubkov, V.G.; Fedyukov, A.S.; Zainulin, Yu.G.

    1988-05-01

    We attempted to make phases having the general formula Ln/sub x/V/sub 2/O/sub 5/ (Ln = La, Eu, Yb) without success; the specimens usually consisted of three phases: the rare-earth orthovanadate LnVO/sub 4/, vanadium(V) oxide, and VO/sub 2/. To shift the process to give Ln/sub x/V/sub 2/O/sub 5/, heat treatment was applied to mixtures of the initial high-purity substances. The x-ray patterns were recorded with a DRON-UM1 apparatus with Cr K..cap alpha.. radiation and were processed by the Poroshok program. The IR spectra were recorded with UR-20 spectrometer with oil mulls.

  2. [Application of ICP-MS to Detect Rare Earth Elements in Three Economic Macroalgaes in China].

    PubMed

    Zhao, Yan-fang; Shang, De-rong; Zhai, Yu-xiu; Ning, Jin-song; Ding, Hai-yan; Sheng, Xiao-feng

    2015-11-01

    In order to investigate the content and distribution of rare earth elements (REE) in main economic macroalgaes in our country, fifteen rare earth elements in three economic macroalgaes (including 30 samples of kelp, 30 samples of laver and 15 samples of Enteromorpha) were detected using ICP-MS method. Results showed that the total content of REE in different species of macroalgaes was different. The highest total content of REE was in Enteromorpha (16,012.0 ng · g⁻¹), while in kelp and laver, the total REE was similar for two macroalgaes (3887.4 and 4318.1 ng · g⁻¹ respectively). The content of fifteen rare earth elements in kelp ranged from 7.9 to 1496.4 ng · g⁻¹; in laver, it ranged from 8.2 to 1836.6 ng · g⁻¹. For Enteromorpha, the concentration of 15 rare earth elements were between 19.2 and 6014.5 ng · g⁻¹. In addition, the content and distribution of different rare earth elements in different macroalgaes was also different. For kelp, the highest content of REE was Ce (1 496.4 ng · g⁻¹), and the second was La (689.1 ng · g⁻¹). For laver, the highest was Y (1836.6 ng · g⁻¹), and the second was Ce (682.2 ng · g⁻¹). For Enteromorpha, the highest was Ce (6014.5 ng · g⁻¹), and the second was La (2902.9 ng · g⁻¹). Present results also showed that three macroalgaes accumulated the light rare earth elements much more than the high rare earth elements. The light rare earth elements occupied 90.9%, 87.3% and 91.1% for kelp, laver and Enteromorpha respectively. The result that the Enteromorpha had high content of rare earth elements could provide important support for opening new research directions for the utilization of Enteromorpha. PMID:26978935

  3. Research of the entry of rare earth elements Eu3+ and La3+ into plant cell.

    PubMed

    Gao, Yongsheng; Zeng, Fuli; Yi, An; Ping, Shi; Jing, Lanhua

    2003-03-01

    Whether rare earth elements can enter into plant cells remains controversial. This article discusses the ultracellular structural localization of lanthanum (La(3+)) and europium (Eu(3+)) in the intact plant cells fed by rare earth elements Eu(3+) and La(3+). Eu-TTA fluorescence analysis of the plasmalemma, cytoplast, and mitochondria showed that Eu(3+) fluorescence intensities in such structures significantly increased. Eu(3+) can directly enter or be carried by the artificial ion carrier A23187 into plant cells through the calcium ion (Ca(2+)) channel and then partially resume the synthesis of amaranthin in the Amaranthus caudatus growing in the dark. Locations of rare earth elements La(3+) and Eu(3+) in all kinds of components of cytoplasmatic organelles were determined with transmission electron microscope, scanning electron microscope, and energy-dispersive X-ray microanalysis. The results of energy-dispersive X-ray microanalysis indicated that Eu(3+) and La(3+) can be absorbed into plant cells and bind to the membranes of protoplasm, chloroplast, mitochondrion, cytoplast, and karyon. These results provide experimental evidence that rare earth elements can be absorbed into plant cells, which would be the basis for interpreting physiological and biochemical effects of rare earth elements on plant cells. PMID:12663949

  4. Molecular Polyarsenides of the Rare-Earth Elements.

    PubMed

    Arleth, Nicholas; Gamer, Michael T; Köppe, Ralf; Konchenko, Sergey N; Fleischmann, Martin; Scheer, Manfred; Roesky, Peter W

    2016-01-22

    Reduction of [Cp*Fe(η(5)-As5)] with [Cp''2Sm(thf)] (Cp''=η(5)-1,3-(tBu)2C5H3) under various conditions led to [(Cp''2Sm)(μ,η(4):η(4)-As4)(Cp*Fe)] and [(Cp''2Sm)2As7(Cp*Fe)]. Both compounds are the first polyarsenides of the rare-earth metals. [(Cp''2Sm)(μ,η(4):η(4)-As4)(Cp*Fe)] is also the first d/f-triple decker sandwich complex with a purely inorganic planar middle deck. The central As4(2-) unit is isolobal with the 6π-aromatic cyclobutadiene dianion (CH)4(2-). [(Cp''2Sm)2As7(Cp*Fe)] contains an As7(3-) cage, which has a norbornadiene-like structure with two short As-As bonds in the scaffold. DFT calculations confirm all the structural observations. The As-As bond order inside the cyclo As4 ligand in [(Cp''2Sm)(μ,η(4):η(4)-As4)(Cp*Fe)] was estimated to be in between an As-As single bond and a formally aromatic As4(2-) system. PMID:26676537

  5. U.S. trade dispute with China over rare earth elements

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2012-03-01

    The U.S. government has brought a new trade case against China over rare earth elements (REE) as well as tungsten and molybdenum, President Barack Obama announced on 13 March. Japan and the European Union also have taken similar actions against China about REEs, which are a group of 17 chemically similar metallic elements that are used in a variety of electronic, optical, magnetic, and catalytic applications. REEs are plentiful in the Earth's crust, although China currently has about 37% of the world's reserves and accounts for more than 95% of the world's production of the elements, according to the British Geological Survey. The United States has requested consultations with China at the World Trade Organization (WTO) concerning "China's unfair export restraints on rare earths, as well as tungsten and molybdenum," the Office of the United States Trade Representative announced in a 13 March statement.

  6. Alkali element depletion by core formation and vaporization on the early Earth

    NASA Technical Reports Server (NTRS)

    Lodders, K.; Fegley, B., Jr.

    1994-01-01

    The depletion of Na, K, Rb, and Cs in the Earth's upper mantle and crust relative to their abundances in chondrites is a long standing problem in geochemistry. Here we consider two commonly invoked mechanisms, namely core formation, and vaporization, for producing the observed depletions. Our models predict that a significant percentage of the Earth's bulk alkali element inventory is in the core (30 percent for Na, 52 percent for K, 74 percent for Rb, and 92 percent for Cs). These predictions agree with independent estimates from nebular volatility trends and (for K) from terrestrial heat flow data. Our models also predict that vaporization and thermal escape during planetary accretion are unlikely to produce the observed alkali element depletion pattern. However, loss during the putative giant impact which formed the Moon cannot be ruled out. Experimental, observational, and theoretical tests of our predictions are also described. Alkali element partitioning into the Earth's core was modeled by assuming that alkali element partitioning during core formation on the aubrite parent body (APB) is analogous to that on the early Earth. The analogy is reasonable for three reasons. First, the enstatite meteorites are the only known meteorites with the same oxygen isotope systematics as the Earth-Moon system. Second, the large core size of the Earth and the V depletion in the mantle requires accretion from planetesimals as reduced as the enstatite chondrites. Third, experimental studies of K partitioning between silicate and metal plus sulfide show that more K goes into the metal plus sulfide at higher pressures than at one atmosphere pressure. Thus partitioning in the relatively low pressure natural laboratory of the APB is a good guide to alkali elemental partitioning during the growth of the Earth.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  9. Rare Earth Element Fractionation During Evaporation of Chondritic Material

    NASA Astrophysics Data System (ADS)

    Wang, J.; Davis, A. M.; Clayton, R. N.

    1993-07-01

    Evaporation experiments suggest that enrichments in the heavy isotopes of oxygen, magnesium, and silicon in some CAIs are caused by kinetic effects during evaporation [1]. Volatility-fractionated REE patterns found in some CAIs have been modeled with some success using equilibrium thermodynamics [2,3], but little is known about kinetic effects on REE patterns. We have begun an investigation of REE fractionation under conditions where large isotope effects are produced by the kinetic isotope effect. We synthesized a starting material containing CI chondritic relative proportions of MgO, Al2O3, SiO2, CaO, TiO2, and FeO, and doped it with 100 ppm each of the REE. Samples of this material were evaporated in a vacuum furnace [4] at 10^-6 torr and 1800 or 2000 degrees C for periods of a few seconds to 5 hr. The mass fraction evaporated ranged from 7.6 to 95.4%. Most residues consist of olivine and glass. Chemical compositions of the residues were determined by electron and ion microprobe. Results for selected elements are shown in Fig. 1. There is no significant evaporation of Ca, Al, and Ti up to 95% mass loss; the evaporation behavior of Mg, Si, and Fe is similar to that found by Hashimoto [5]. There is no significant evaporation of most of the REE up to 95% mass loss. Ce is much more volatile than the other REE under these conditions: a tenfold negative Ce anomaly developed between 60 and 70% mass loss and the anomaly reached 5 X 10^-4 at 95% mass loss. A small Pr anomaly (50% Pr loss) also appeared in the highest-mass-loss residue. Thermodynamic calculations show that Ce has approximately the same volatility as other LREE under solar nebular oxygen fugacity, but is much more volatile than the other REE under oxidizing conditions [6]. We suspect that conditions in the residue in our vacuum evaporation experiments became oxidizing because evaporation reactions involving most major element oxides involve release of oxygen. The four known HAL-type hibonite

  10. Statistical Constraints from Siderophile Elements on Earth's Accretion, Differentiation, and Initial Core Stratification

    NASA Astrophysics Data System (ADS)

    O'Rourke, J. G.; Stevenson, D. J.

    2015-12-01

    Abundances of siderophile elements in the primitive mantle constrain the conditions of Earth's core/mantle differentiation. Core growth occurred as Earth accreted from collisions between planetesimals and larger embryos of unknown original provenance, so geochemistry is directly related to the overall dynamics of Solar System formation. Recent studies claim that only certain conditions of equilibration (pressure, temperature, and oxygen fugacity) during core formation can reproduce the available data. Typical analyses, however, only consider the effects of varying a few out of tens of free parameters in continuous core formation models. Here we describe the Markov chain Monte Carlo method, which simultaneously incorporates the large uncertainties on Earth's composition and the parameterizations that describe elemental partitioning between metal and silicate. This Bayesian technique is vastly more computationally efficient than a simple grid search and is well suited to models of planetary accretion that involve a plethora of variables. In contrast to previous work, we find that analyses of siderophile elements alone cannot yield a unique scenario for Earth's accretion. Our models predict a wide range of possible light element contents for the core, encompassing all combinations permitted by seismology and mineral physics. Specifically, we are agnostic between silicon and oxygen as the dominant light element, and the addition of carbon or sulfur is also permissible but not well constrained. Redox conditions may have remained roughly constant during Earth's accretion or relatively oxygen-rich material could have been incorporated before reduced embryos. Pressures and temperatures of equilibration, likewise, may only increase slowly throughout accretion. Therefore, we do not necessarily expect a thick (>500 km), compositionally stratified layer that is stable against convection to develop at the top of the core of Earth (or, by analogy, Venus). A thinner stable layer

  11. Rare earth element content of thermal fluids from Surprise Valley, California

    DOE Data Explorer

    Andrew Fowler

    2015-09-23

    Rare earth element measurements for thermal fluids from Surprise Valley, California. Samples were collected in acid washed HDPE bottles and acidified with concentrated trace element clean (Fisher Scientific) nitric acid. Samples were pre-concentratated by a factor of approximately 10 using chelating resin with and IDA functional group and measured on magnetic sector ICP-MS. Samples include Seyferth Hot Springs, Surprise Valley Resort Mineral Well, Leonard's Hot Spring, and Lake City Mud Volcano Boiling Spring.

  12. Radioluminescence and thermoluminescence of rare earth element and phosphorus-doped zircon

    SciTech Connect

    Karali, T.; Can, N.; Townsend, P.D.; Rowlands, A.P.; Hanchar, J.M.

    2000-06-01

    The radioluminescence and thermoluminescence spectra of synthetic zircon crystals doped with individual trivalent rare earth element (REE) ions (Pr, Sm, Eu, Gd, Dy, Ho, Er, and Yb) and P are reported in the temperature range 25 to 673 K. Although there is some intrinsic UV/blue emission from the host lattice, the dominant signals are from the rare-earth sites, with signals characteristic of the REE{sup 3+} states. The shapes of the glow curves are different for each dopant, and there are distinct differences between glow peak temperatures for different rare-earth lines of the same element. Within the overall set of signals there are indications of linear trends in which some glow peak temperatures vary as a function of the ionic size of the rare earth ions. The temperature shifts of the peaks are considerable, up to 200{degree}, and much larger than those cited in other rare-earth-doped crystals of LaF{sub 3} and Bi{sub 4}Ge{sub 3}O{sub 12}. The data clearly suggest that the rare-earth ions are active both in the trapping and luminescence steps, and hence the TL occurs within localized defect complexes that include REE{sup 3+} ions.

  13. Composition of the earth's upper mantle. I - Siderophile trace elements in ultramafic nodules

    NASA Technical Reports Server (NTRS)

    Morgan, J. W.; Wandless, G. A.; Petrie, R. K.; Irving, A. J.

    1981-01-01

    The considered investigation is concerned with a reexamination of the question of the distribution of siderophile elements in the earth's upper mantle, taking into account a more unified data base which is now available. A comprehensive suite of ultramafic inclusions was collected as part of the Basaltic Volcanism Study Project and has been analyzed by instrument neutron activation analysis for major, minor, and some lithophile trace elements. In addition, 18 of these rocks and the important sheared garnet lherzolite PHN 1611 have been analyzed by means of radiochemical neutron activation analysis for 7 siderophile elements (Au, Ge, Ir, Ni, Os, Pd, and Re) and 9 volatile elements (Ag, Bi, Cd, In, Sb, Se, Te, Tl, and Zn). The siderophile element data reveal interesting inter-element correlations, which were not apparent from the compiled abundance tables of Ringwood and Kesson (1976) and Chou (1978).

  14. Preliminary study on using rare earth elements to trace non-point source phosphorous loss

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The environmental fate of phosphorus (P) is of concern as P is a primary cause of freshwater eutrophication. Rare earth elements (REEs) have been successfully used in the analysis of soil erosion and pollutant sources, as well as in the analysis of mineral genesis. To better understand the potential...

  15. Undecaprenyl Pyrophosphate Involvement in Susceptibility of Bacillus subtilis to Rare Earth Elements

    PubMed Central

    Ochi, Kozo

    2012-01-01

    The rare earth element scandium has weak antibacterial potency. We identified a mutation responsible for a scandium-resistant phenotype in Bacillus subtilis. This mutation was found within the uppS gene, which encodes undecaprenyl pyrophosphate synthase, and designated uppS86 (for the Thr-to-Ile amino acid substitution at residue 86 of undecaprenyl pyrophosphate synthase). The uppS86 mutation also gave rise to increased resistance to bacitracin, which prevents cell wall synthesis by inhibiting the dephosphorylation of undecaprenyl pyrophosphate, in addition to enhanced amylase production. Conversely, overexpression of the wild-type uppS gene resulted in increased susceptibilities to both scandium and bacitracin. Moreover, the mutant lacking undecaprenyl pyrophosphate phosphatase (BcrC) showed increased susceptibility to all rare earth elements tested. These results suggest that the accumulation of undecaprenyl pyrophosphate renders cells more susceptible to rare earth elements. The availability of undecaprenyl pyrophosphate may be an important determinant for susceptibility to rare earth elements, such as scandium. PMID:22904278

  16. Tracing sediment movement on semi-arid watershed using Rare Earth Elements 1988

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A multi-tracer method employing rare earth elements (REE) was used to determine sediment yield and to track sediment movement in a small semiarid watershed. A 0.33 ha watershed near Tombstone, AZ was divided into five morphological units, each tagged with one of five REE oxides. Relative contributi...

  17. A LOW-COST RARE EARTH ELEMENTS RECOVERY TECHNOLOGY - PHASE I

    EPA Science Inventory

    Physical Sciences, Inc., and the University of Kentucky Center for Applied Energy Research propose to develop a unique enabling technology to significantly reduce U.S. dependency for Rare Earth Elements (REE) on foreign suppliers and our global competitors. Our innovation...

  18. Interactions between exogenous rare earth elements and phosphorus leaching in packed soil columns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rare earth elements (REEs) increasingly used in agriculture as an amendment for crop growth may help to lessen environmental losses of phosphorus (P) from heavily fertilized soils. The vertical transport characteristics of P and REEs, lanthanum (La), neodymium (Nd), samarium (Sm), and cerium (Ce), w...

  19. SEDIMENT REWORKING AND TRANSPORT IN EASTERN LAKE SUPERIOR: IN SITU RARE EARTH ELEMENT TRACER STUDIES

    EPA Science Inventory

    A rare earth element (REE) tracer pellet was deployed at the floor of the Ile Parisienne basin of eastern Lake Superior to measure representative sediment reworking and transport processes in the benthic boundary layer of the prnfundal Great Lakes. Samarium oxide, a high neutron-...

  20. Catalytic Graphitization of Coal-Based Carbon Materials with Light Rare Earth Elements.

    PubMed

    Wang, Rongyan; Lu, Guimin; Qiao, Wenming; Yu, Jianguo

    2016-08-30

    The catalytic graphitization mechanism of coal-based carbon materials with light rare earth elements was investigated using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, selected-area electron diffraction, and high-resolution transmission electron microscopy. The interface between light rare earth elements and carbon materials was carefully observed, and two routes of rare earth elements catalyzing the carbon materials were found: dissolution-precipitation and carbide formation-decomposition. These two simultaneous processes certainly accelerate the catalytic graphitization of carbon materials, and light rare earth elements exert significant influence on the microstructure and thermal conductivity of graphite. Moreover, by virtue of praseodymium (Pr), it was found that a highly crystallographic orientation of graphite was induced and formed, which was reasonably attributed to the similar arrangements of the planes perpendicular to (001) in both graphite and Pr crystals. The interface between Pr and carbon was found to be an important factor for the orientation of graphite structure. PMID:27482724

  1. Fluid rare earth element anlayses from wells RN-12 and RN-19, Reykjanes, Iceland

    DOE Data Explorer

    Andrew Fowler

    2015-07-24

    Results for fluid rare earth elment analyses from Reykjanes wells RN-12 and RN-19. The data have not been corrected for flashing. Samples preconcetrated using chelating resin with IDA functional group (InertSep ME-1). Analyzed using and Element magnetic sctor ICP-MS.

  2. Technical Information Resource on Rare Earth Elements Now Available to Public and Private Sector Stakeholders

    EPA Science Inventory

    A new EPA technical information resource, “Rare Earth Elements: A Review of Production, Processing, Recycling, and Associated Environmental Issues” has been produced as an introductory resource for those interested in learning more about REE mining and alternatives to meet demand...

  3. Studying the volatility of pyrazolone complexes of rare-earth elements by means of Knudsen effusion

    NASA Astrophysics Data System (ADS)

    Lazarev, N. M.; Petrov, B. I.; Bochkarev, L. N.; Safronova, A. V.; Abakumov, G. A.; Arapova, A. V.; Bessonova, Yu. A.

    2014-08-01

    The temperature dependences of the pressure of saturated vapor of pyrazolone complexes of rare-earth elements Ln(PMIP)3 (where Ln = Y, Ho, Er, Tm, Lu; PMIP = 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone) are studied via Knudsen effusion, and the enthalpy of their sublimation is determined. Mass spectra and differential scanning calorimetry data are obtained.

  4. Compilation of Rare Earth Element Analyses from US Geothermal Fields and Mid Ocean Ridge Hydrothermal Vents

    DOE Data Explorer

    Andrew Fowler

    2015-10-01

    Compilation of rare earth element and associated major and minor dissolved constituent analytical data for USA geothermal fields and global seafloor hydrothermal vents. Data is in original units. Reference to and use of this data should be attributed to the original authors and publications according to the provisions outlined therein.

  5. Method to Recover Media Ligand Losses During Sorption of Rare Earth Elements from Simulated Geothermal Brines

    DOE Data Explorer

    Dean Stull

    2016-05-24

    This document describes the method and results of an in-situ experiment used to confirm that ligand bleed from a sorptive media can be contained. The experiment focused on maintaining the media's sorption of rare earth elements (REE) obtained from a simulated geothermal brine doped with known mineral concentrations.

  6. Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets.

    PubMed

    Imashuku, Susumu; Wagatsuma, Kazuaki; Kawai, Jun

    2016-02-01

    Scanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium-iron-boron (NdFeB) and samarium-cobalt (Sm-Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm-Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium. PMID:26739864

  7. Uranium and rare earth elements in CO 2-rich waters from Vals-les-Bains (France)

    NASA Astrophysics Data System (ADS)

    Michard, Annie; Beaucaire, Catherine; Michard, Gil

    1987-04-01

    Waters from springs at Vals-les-Bains result from the mixing of a CO 2-rich, highly mineralized water with dilute, shallow subsurface water. Total content of dissolved species vary from 5 mmol/1 to 100 mmol/1. For many elements, mixing of these waters is non-linear (non-conservative) and further water-rock reactions take place. The pH is controlled by CO 2 outgassing, redox conditions are controlled by both the iron hydroxide-siderite buffer and the introduction of oxygen with shallow subsurface waters. Among the major elements, concentrations of Ca, Mg, Mn, Fe, are related to mixing, CO 2 outgassing and carbonate precipitation. Uranium shows a complex behaviour controlled by carbonate complexing, redox conditions, mixing of waters and leaching from the rocks. The 234U /238U activity ratio is near secular equilibrium. In the more dilute waters, dissolved rare earth element (REE) patterns are almost flat with a slight negative Eu anomaly. In the concentrated waters, heavy rare earth elements (Gd-Yb, HREE) are strongly enriched relative to light rare earth elements (Ce-Eu, LREE). We relate the enrichment in HREE to water chemistry and to complexing with carbonate species.

  8. Study on Orbital Decay of Near Earth Satellites with KS Orthogonal Elements

    NASA Astrophysics Data System (ADS)

    Ps, Sandeep

    STUDY ON ORBITAL DECAY OF NEAR EARTH SATELLITES WITH KS ORTHOGONAL ELEMENTS SANDEEP P S The knowledge of satellite orbit decay and its expected life prior to launch is necessary for mission planning purpose. Several sets of data for various parametric studies is sought quite often, it is necessary to minimize computational time involved for generating decay predictions, keeping the prediction accuracy normally good. A number of factors play dominant role in perturbation modelling for near earth satellites such as oblateness of the Earth, presence of the atmosphere, luni-solar attraction and solar radiation pressure. This paper concerns with the study of orbital decay of near earth satellites with KS orthogonal elements, which provide accurate orbit predictions at low computational time. Perturbations considered are due to oblateness of the Earth and the atmospheric drag. The Earth’s zonal harmonic terms J2 to J6 are included and the drag is modeled with an analytical diurnally oblate atmosphere. Effect of Earth’s geomagnetic and solar activity is included in density and density scale height computations. JACCHIA77 atmospheric model is utilized. The developed software is validated with the orbital data of decayed objects taken from www.space-track.org.

  9. Origin of the earth's moon - Constraints from alkali volatile trace elements

    NASA Technical Reports Server (NTRS)

    Kreutzberger, M. E.; Drake, M. J.; Jones, J. H.

    1986-01-01

    Although the moon is depleted in volatile elements compared to the earth, these depletions are not in accord with simple volatility. For example, the Cs/Rb ratios of the earth and moon inferred from basalt are approximately one seventh and one half of the CI ratio, respectively. Volatility considerations alone predict that the lunar Cs/Rb ratio should be equal to or lower than the terrestrial ratio if the moon was derived entirely from earth mantle material. Thus hypotheses such as rotational fission which invoke derivation of lunar material entirely from the earth's mantle may be excluded. The collisional ejection hypothesis of lunar origin requires at least 18 percent of lunar material to be derived from a projectile with dehydrated CI composition to match the lunar Cs/Rb ratio, and 25-50 percent to match both the lunar Cs/Rb ratio and absolute concentrations of Cs and Rb. It remains to be demonstrated that this relatively large contribution of projectile material is consistent with other elemental abundances and element ratios in the moon.

  10. Heavy metals and rare earth elements source-sink in some Egyptian cigarettes as determined by neutron activation analysis.

    PubMed

    Nada, A; Abdel-Wahab, M; Sroor, A; Abdel-Haleem, A S; Abdel-Sabour, M F

    1999-07-01

    Heavy metals and rare earth elements in two types of cigarettes were studied. The contents of trace elements were determined by using delayed neutron activation analysis. In the present study 11 elements have been detected in popular and fine brand cigarettes marketed in Egypt. Evaluation of these elements with their potential hazards for smokers is briefly discussed. The material balance (source and sink) for each element was determined. Also the ratio of element recovery to the total amount was assessed. PMID:10376325

  11. Structural Responses and Finite Element Modeling of Hakka Tulou Rammed Earth Structures

    NASA Astrophysics Data System (ADS)

    Sranislawski, Daniel

    Hakka Tulous are rammed earth structures that have survived the effects of aging and natural elements upwards of even over a thousand years. These structures have housed the Hakka people of the Fujian Province, China in natural yet modern housing that has provided benefits over newer building materials. The key building material, rammed earth, which is used for the walls of the Hakka Tulou structures, has provided structural stability along with thermal comfort to the respective inhabitants of the Hakka Tulous. Through material testing and analysis this study has examined how the Tulou structures have maintained their structural stability while also providing thermal comfort. Reports of self healing cracks in the rammed earth walls were also analyzed for their validity in this study. The study has found that although the story of the self healing crack cannot be validated, there is reason to believe that with the existence of lime, some type of autogenous healing could occur on a small scale. The study has also found, through the use of nondestructive testing, that both the internal wooden systems (flooring, roof, and column support) and the rammed earth walls, are still structurally sound. Also, rammed earth's high thermal mass along with the use of sufficient shading has allowed for a delay release of heat energy from the walls of the Tulous, thus providing thermal comfort that can be felt during both night and day temperatures. The Hakka Tulou structures have been found to resist destruction from natural disasters such as strong earthquakes even when more modern construction has not. Through finite element modeling, this study has shown that the high volume of rammed earth used in the construction of the Hakka Tulous helps dissipate lateral force energy into much lower stresses for the rammed earth wall. This absorption of lateral force energy allows the rammed earth structures to survive even the strongest of earthquakes experienced in the region. The Hakka

  12. Accurate projected augmented wave (PAW) datasets for rare-earth elements (RE=La-Lu)

    NASA Astrophysics Data System (ADS)

    Topsakal, Mehmet; Wentzcovitch, Renata

    2015-03-01

    We provide accurate projected augmented wave (PAW) datasets for rare-earth (RE) elements with some suggested Hubbard U values allowing efficient plane-wave calculations. Solid state tests of generated datasets were performed on rare-earth nitrides. Through density of state (DOS) and equation of state (EoS) comparisons, generated datasets were shown to yield excellent results comparable to highly accurate all-electron full-potential linearized augmented plane-wave plus local orbital (FLAPW+LO) calculations. Hubbard U values for trivalent RE ions are determined according to hybrid functional calculations. We believe that these new and open-source PAW datasets will allow further studies on rare-earth materials. NSF/EAR 1319361

  13. Highly siderophile elements were stripped from Earth's mantle by iron sulfide segregation.

    PubMed

    Rubie, David C; Laurenz, Vera; Jacobson, Seth A; Morbidelli, Alessandro; Palme, Herbert; Vogel, Antje K; Frost, Daniel J

    2016-09-01

    Highly siderophile elements (HSEs) are strongly depleted in the bulk silicate Earth (BSE) but are present in near-chondritic relative abundances. The conventional explanation is that the HSEs were stripped from the mantle by the segregation of metal during core formation but were added back in near-chondritic proportions by late accretion, after core formation had ceased. Here we show that metal-silicate equilibration and segregation during Earth's core formation actually increased HSE mantle concentrations because HSE partition coefficients are relatively low at the high pressures of core formation within Earth. The pervasive exsolution and segregation of iron sulfide liquid from silicate liquid (the "Hadean matte") stripped magma oceans of HSEs during cooling and crystallization, before late accretion, and resulted in slightly suprachondritic palladium/iridium and ruthenium/iridium ratios. PMID:27609889

  14. Thulium anomalies and rare earth element patterns in meteorites and Earth: Nebular fractionation and the nugget effect

    NASA Astrophysics Data System (ADS)

    Dauphas, Nicolas; Pourmand, Ali

    2015-08-01

    This study reports the bulk rare earth element (REEs, La-Lu) compositions of 41 chondrites, including 32 falls and 9 finds from carbonaceous (CI, CM, CO and CV), enstatite (EH and EL) and ordinary (H, L and LL) groups, as well as 2 enstatite achondrites (aubrite). The measurements were done in dynamic mode using multi-collector inductively coupled plasma mass spectrometers (MC-ICPMS), allowing precise quantification of mono-isotopic REEs (Pr, Tb, Ho and Tm). The CI-chondrite-normalized REE patterns (LaN/LuN; a proxy for fractionation of light vs. heavy REEs) and Eu anomalies in ordinary and enstatite chondrites show more scatter in more metamorphosed (petrologic types 4-6) than in unequilibrated (types 1-3) chondrites. This is due to parent-body redistribution of the REEs in various carrier phases during metamorphism. A model is presented that predicts the dispersion of elemental and isotopic ratios due to the nugget effect when the analyzed sample mass is limited and elements are concentrated in minor grains. The dispersion in REE patterns of equilibrated ordinary chondrites is reproduced well by this model, considering that REEs are concentrated in 200 μm-size phosphates, which have high LaN/LuN ratios and negative Eu anomalies. Terrestrial rocks and samples from ordinary and enstatite chondrites display negative Tm anomalies of ∼-4.5% relative to CI chondrites. In contrast, CM, CO and CV (except Allende) show no significant Tm anomalies. Allende CV chondrite shows large excess Tm (∼+10%). These anomalies are similar to those found in group II refractory inclusions in meteorites but of much smaller magnitude. The presence of Tm anomalies in meteorites and terrestrial rocks suggests that either (i) the material in the inner part of the solar system was formed from a gas reservoir that had been depleted in refractory dust and carried positive Tm anomalies or (ii) CI chondrites are enriched in refractory dust and are not representative of solar composition for

  15. Symmetric charge-transfer cross sections of IIIa rare-earth-metal elements

    SciTech Connect

    Hashida, Masaki; Sakabe, Shuji; Izawa, Yasukazu

    2011-03-15

    Symmetric charge-transfer cross sections of IIIa rare-earth-metal elements (Sc, Y, and Gd) in the impact energy range of 30 to 1000 eV were measured for the first time. The experiments were performed with a crossed-beam apparatus that featured primary ion production by photoionization with a tunable dye laser. Comparing the cross sections of IIIa rare-earth-metal elements ({sigma}{sub Sc}, {sigma}{sub Y}, and {sigma}{sub Gd}) with those of alkali metals or helium {sigma}{sub 0}, we found that {sigma}{sub 0{approx_equal}{sigma}Sc}<{sigma}{sub Y}<{sigma}{sub Gd{approx_equal}}2{sigma}{sub 0}at an impact energy of 1000 eV.

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

    SciTech Connect

    Turanov, A.N.; Karandashev, V.K.; Baulin, V.E.

    1999-11-01

    The extraction of microquantities of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y from HNO{sub 3} 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 HNO{sub 3} 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.

  17. Bishop tuff revisited: new rare Earth element data consistent with crystal fractionation.

    PubMed

    Cameron, K L

    1984-06-22

    The Bishop Tuff of eastern California is the type example of a high-silica rhyolite that, according to Hildreth, supposedly evolved by liquid-state differentiation. New analyses establish that the Bishop Tuff "earlyllate" rare earth element trend reported by Hildreth mimics the relations between groundmass glasses and whole rocks for allanite-bearing pumice. Differences in elemental concentrations between whole rock and groundmass are the result of phenocryst precipitation; thus the data of Hildreth are precisely those expected to result from crystal fractionation. PMID:17837193

  18. Transport of rare earth element-tagged soil particles in response to thunderstorm runoff.

    PubMed

    Matisoff, G; Ketterer, M E; Wilson, C G; Layman, R; Whiting, P J

    2001-08-15

    The downslope transport of rare earth element-tagged soil particles remobilized during a spring thunderstorm was studied on both a natural prairie and an agricultural field in southwestern Iowa (U.S.A.). A technique was developed for tagging natural soils with the rare earth elements Eu, Tb, and Ho to approximately 1,000 ppm via coprecipitation with MnO2. Tagged material was replaced in target locations; surficial soil samples were collected following precipitation and runoff; and rare earth element concentrations were determined by inductively coupled plasma mass spectrometry. Diffusion and exponential models were applied to the concentration-distance data to determine particle transport distances. The results indicate that the concentration-distance data are well described by the diffusion model, butthe exponential model does not simulate the rapid drop-off in concentrations near the tagged source. Using the diffusion model, calculated particle transport distances at all hillside locations and at both the cultivated and natural prairie sites were short, ranging from 3 to 73 cm during this single runoff event. This study successfully demonstrates a new tool for studying soil erosion. PMID:11529577

  19. Evaluating rare earth element availability: a case with revolutionary demand from clean technologies.

    PubMed

    Alonso, Elisa; Sherman, Andrew M; Wallington, Timothy J; Everson, Mark P; Field, Frank R; Roth, Richard; Kirchain, Randolph E

    2012-03-20

    The future availability of rare earth elements (REEs) is of concern due to monopolistic supply conditions, environmentally unsustainable mining practices, and rapid demand growth. We present an evaluation of potential future demand scenarios for REEs with a focus on the issue of comining. Many assumptions were made to simplify the analysis, but the scenarios identify some key variables that could affect future rare earth markets and market behavior. Increased use of wind energy and electric vehicles are key elements of a more sustainable future. However, since present technologies for electric vehicles and wind turbines rely heavily on dysprosium (Dy) and neodymium (Nd), in rare-earth magnets, future adoption of these technologies may result in large and disproportionate increases in the demand for these two elements. For this study, upper and lower bound usage projections for REE in these applications were developed to evaluate the state of future REE supply availability. In the absence of efficient reuse and recycling or the development of technologies which use lower amounts of Dy and Nd, following a path consistent with stabilization of atmospheric CO(2) at 450 ppm may lead to an increase of more than 700% and 2600% for Nd and Dy, respectively, over the next 25 years if the present REE needs in automotive and wind applications are representative of future needs. PMID:22304002

  20. Hydrometallurgical separation of rare earth elements, cobalt and nickel from spent nickel-metal-hydride batteries

    NASA Astrophysics Data System (ADS)

    Rodrigues, Luiz Eduardo Oliveira Carmo; Mansur, Marcelo Borges

    The separation of rare earth elements, cobalt and nickel from NiMH battery residues is evaluated in this paper. Analysis of the internal content of the NiMH batteries shows that nickel is the main metal present in the residue (around 50% in weight), as well as potassium (2.2-10.9%), cobalt (5.1-5.5%), rare earth elements (15.3-29.0%) and cadmium (2.8%). The presence of cadmium reveals that some Ni-Cd batteries are possibly labeled as NiMH ones. The leaching of nickel and cobalt from the NiMH battery powder with sulfuric acid is efficient; operating variables temperature and concentration of H 2O 2 has no significant effect for the conditions studied. A mixture of rare earth elements is separated by precipitation with NaOH. Finally, solvent extraction with D2EHPA (di-2-ethylhexyl phosphoric acid) followed by Cyanex 272 (bis-2,4,4-trimethylpentyl phosphinic acid) can separate cadmium, cobalt and nickel from the leach liquor. The effect of the main operating variables of both leaching and solvent extraction steps are discussed aiming to maximize metal separation for recycling purposes.

  1. Highly siderophile elements in Earth's mantle as a clock for the Moon-forming impact.

    PubMed

    Jacobson, Seth A; Morbidelli, Alessandro; Raymond, Sean N; O'Brien, David P; Walsh, Kevin J; Rubie, David C

    2014-04-01

    According to the generally accepted scenario, the last giant impact on Earth formed the Moon and initiated the final phase of core formation by melting Earth's mantle. A key goal of geochemistry is to date this event, but different ages have been proposed. Some argue for an early Moon-forming event, approximately 30 million years (Myr) after the condensation of the first solids in the Solar System, whereas others claim a date later than 50 Myr (and possibly as late as around 100 Myr) after condensation. Here we show that a Moon-forming event at 40 Myr after condensation, or earlier, is ruled out at a 99.9 per cent confidence level. We use a large number of N-body simulations to demonstrate a relationship between the time of the last giant impact on an Earth-like planet and the amount of mass subsequently added during the era known as Late Accretion. As the last giant impact is delayed, the late-accreted mass decreases in a predictable fashion. This relationship exists within both the classical scenario and the Grand Tack scenario of terrestrial planet formation, and holds across a wide range of disk conditions. The concentration of highly siderophile elements (HSEs) in Earth's mantle constrains the mass of chondritic material added to Earth during Late Accretion. Using HSE abundance measurements, we determine a Moon-formation age of 95 ± 32 Myr after condensation. The possibility exists that some late projectiles were differentiated and left an incomplete HSE record in Earth's mantle. Even in this case, various isotopic constraints strongly suggest that the late-accreted mass did not exceed 1 per cent of Earth's mass, and so the HSE clock still robustly limits the timing of the Moon-forming event to significantly later than 40 Myr after condensation. PMID:24695310

  2. Highly siderophile elements in Earth's mantle as a clock for the Moon-forming impact

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.; Morbidelli, Alessandro; Raymond, Sean N.; O'Brien, David P.; Walsh, Kevin J.; Rubie, David C.

    2014-04-01

    According to the generally accepted scenario, the last giant impact on Earth formed the Moon and initiated the final phase of core formation by melting Earth's mantle. A key goal of geochemistry is to date this event, but different ages have been proposed. Some argue for an early Moon-forming event, approximately 30 million years (Myr) after the condensation of the first solids in the Solar System, whereas others claim a date later than 50 Myr (and possibly as late as around 100 Myr) after condensation. Here we show that a Moon-forming event at 40 Myr after condensation, or earlier, is ruled out at a 99.9 per cent confidence level. We use a large number of N-body simulations to demonstrate a relationship between the time of the last giant impact on an Earth-like planet and the amount of mass subsequently added during the era known as Late Accretion. As the last giant impact is delayed, the late-accreted mass decreases in a predictable fashion. This relationship exists within both the classical scenario and the Grand Tack scenario of terrestrial planet formation, and holds across a wide range of disk conditions. The concentration of highly siderophile elements (HSEs) in Earth's mantle constrains the mass of chondritic material added to Earth during Late Accretion. Using HSE abundance measurements, we determine a Moon-formation age of 95 +/- 32 Myr after condensation. The possibility exists that some late projectiles were differentiated and left an incomplete HSE record in Earth's mantle. Even in this case, various isotopic constraints strongly suggest that the late-accreted mass did not exceed 1 per cent of Earth's mass, and so the HSE clock still robustly limits the timing of the Moon-forming event to significantly later than 40 Myr after condensation.

  3. A Study on Removal of Rare Earth Elements from U.S. Coal Byproducts by Ion Exchange

    NASA Astrophysics Data System (ADS)

    Rozelle, Peter L.; Khadilkar, Aditi B.; Pulati, Nuerxida; Soundarrajan, Nari; Klima, Mark S.; Mosser, Morgan M.; Miller, Charles E.; Pisupati, Sarma V.

    2016-03-01

    Rare earth elements are known to occur in low concentrations in U.S. coals and coal byproducts. These low concentrations may make rare earth element recovery from these materials unattractive, using only physical separation techniques. However, given the significant production of rare earths through ion exchange extraction in China, two U.S. coal byproducts were examined for ion extraction, using ammonium sulfate, an ionic liquid, and a deep eutectic solvent as lixiviants. Extraction of rare earth elements in each case produced high recoveries of rare earth elements to the solution. This suggests that in at least the cases of the materials examined, U.S. coal byproducts may be technically suitable as REE ores. More work is required to establish economic suitability.

  4. Siku: A Sea Ice Discrete Element Method Model on a Spherical Earth

    NASA Astrophysics Data System (ADS)

    Kulchitsky, A. V.; Hutchings, J. K.; Johnson, J.

    2014-12-01

    Offshore oil and gas exploration and production activities in the Beaufort and Chukchi Seas can be significantly and adversely affected by sea ice. In the event of an oil spill, sea ice complicates the tracking of ice/oil trajectories and can hinder cleanup operations. There is a need for a sea ice dynamics model that can accurately simulate ice pack deformation and failure to improve the ability to track ice/oil trajectories and support oil response operations. A discrete element method (DEM) model, where each ice floe is represented by discrete elements that are initially bonded (frozen) together will be used to address the difficulty continuum modeling approaches have with representing discrete phenomena in sea ice, such as the formation of leads and ridges. Each discrete element in the DEM is a rigid body driven by environmental forcing (wind, current and Coriolis forces) and interaction forces with other discrete elements (compression, shear, tension, bond rupture and regrowth). We introduce a new DEM model ``Siku'', currently under development, to simulate ice drift of an ice floe on a spherical Earth. We will present initial free-drift results. Siku is focused on improving sea ice interaction mechanics and providing an accurate geometrical representation needed for basin scale and regional simulations. Upon completion, Siku will be an open source GNU GPL licensed user friendly program with embedded python capability for setting up simulations "scenarios" and coupling with other models to provide forcing fields. We use a unique quaternion representation for position and orientation of polygon sea-ice elements that use a second order integration scheme of sea-ice element motion on the Earth's sphere that does not depend on the location of the element and, hence, avoids numerical problems near the pole.

  5. Determination of rare earth elements in environmental materials by inductively coupled plasma mass spectrometry

    SciTech Connect

    Panday, V.K.; Hoppstock, K.; Becker, J.S.; Dietze, H.J.

    1996-09-01

    Despite the fact that rare earth elements (REE) have found increasing use in modern technology only few data are available on their concentrations in biological and environmental samples. Inductively coupled plasma mass spectrometry (ICP-MS) has been employed to study the concentration of rare earth elements (REE) in various environmental materials (e.g., pine needles, mussel tissue, apple leaves) available from National Institute of Standards and Technology (NIST), the Bureau of European Communities (BCR), and the German Environmental Specimens Bank. After the decomposition of the environmental samples with HNO{sub 3}, the REE (present mostly in the ng/g-range) were separated from the matrix and simultaneously preconcentrated using liquid-liquid extraction with bis(2-ethyl hexyl)-ortho-phosphoric acid (HDEHP) in toluene as a selective reagent at pH = 2 and subsequent back extraction of the elements into the aqueous by 6M HNO{sub 3}. Recoveries of better 90% were obtained for almost all REE. A Perkin Elmer/Sciex ELAN 5000 ICP-MS and HR-ICP-MS ELEMENT from Finnigan MAT were used for quantitative analysis (by external calibration and ID-ICP-MS) of REE. The results of determination of REE concentrations agree well with the data available on some of these materials. Further supplement information on the contents of various REE in these materials.

  6. Normalized rare earth elements in water, sediments, and wine: identifying sources and environmental redox conditions

    USGS Publications Warehouse

    Piper, David Z.; Bau, Michael

    2013-01-01

    The concentrations of the rare earth elements (REE) in surface waters and sediments, when normalized on an element-by-element basis to one of several rock standards and plotted versus atomic number, yield curves that reveal their partitioning between different sediment fractions and the sources of those fractions, for example, between terrestrial-derived lithogenous debris and seawater-derived biogenous detritus and hydrogenous metal oxides. The REE of ancient sediments support their partitioning into these same fractions and further contribute to the identification of the redox geochemistry of the sea water in which the sediments accumulated. The normalized curves of the REE that have been examined in several South American wine varietals can be interpreted to reflect the lithology of the bedrock on which the vines may have been grown, suggesting limited fractionation during soil development.

  7. Quantification of rare earth elements using laser-induced breakdown spectroscopy

    SciTech Connect

    Martin, Madhavi; Martin, Rodger C.; Allman, Steve; Brice, Deanne; Wymore, Ann; Andre, Nicolas

    2015-10-21

    In this paper, a study of the optical emission as a function of concentration of laser-ablated yttrium (Y) and of six rare earth elements, europium (Eu), gadolinium (Gd), lanthanum (La), praseodymium (Pr), neodymium (Nd), and samarium (Sm), has been evaluated using the laser-induced breakdown spectroscopy (LIBS) technique. Statistical methodology using multivariate analysis has been used to obtain the sampling errors, coefficient of regression, calibration, and cross-validation of measurements as they relate to the LIBS analysis in graphite-matrix pellets that were doped with elements at several concentrations. Each element (in oxide form) was mixed in the graphite matrix in percentages ranging from 1% to 50% by weight and the LIBS spectra obtained for each composition as well as for pure oxide samples. Finally, a single pellet was mixed with all the elements in equal oxide masses to determine if we can identify the elemental peaks in a mixed pellet. This dataset is relevant for future application to studies of fission product content and distribution in irradiated nuclear fuels. These results demonstrate that LIBS technique is inherently well suited for the future challenge of in situ analysis of nuclear materials. Finally, these studies also show that LIBS spectral analysis using statistical methodology can provide quantitative results and suggest an approach in future to the far more challenging multielemental analysis of ~ 20 primary elements in high-burnup nuclear reactor fuel.

  8. Quantification of rare earth elements using laser-induced breakdown spectroscopy

    DOE PAGESBeta

    Martin, Madhavi; Martin, Rodger C.; Allman, Steve; Brice, Deanne; Wymore, Ann; Andre, Nicolas

    2015-10-21

    In this paper, a study of the optical emission as a function of concentration of laser-ablated yttrium (Y) and of six rare earth elements, europium (Eu), gadolinium (Gd), lanthanum (La), praseodymium (Pr), neodymium (Nd), and samarium (Sm), has been evaluated using the laser-induced breakdown spectroscopy (LIBS) technique. Statistical methodology using multivariate analysis has been used to obtain the sampling errors, coefficient of regression, calibration, and cross-validation of measurements as they relate to the LIBS analysis in graphite-matrix pellets that were doped with elements at several concentrations. Each element (in oxide form) was mixed in the graphite matrix in percentages rangingmore » from 1% to 50% by weight and the LIBS spectra obtained for each composition as well as for pure oxide samples. Finally, a single pellet was mixed with all the elements in equal oxide masses to determine if we can identify the elemental peaks in a mixed pellet. This dataset is relevant for future application to studies of fission product content and distribution in irradiated nuclear fuels. These results demonstrate that LIBS technique is inherently well suited for the future challenge of in situ analysis of nuclear materials. Finally, these studies also show that LIBS spectral analysis using statistical methodology can provide quantitative results and suggest an approach in future to the far more challenging multielemental analysis of ~ 20 primary elements in high-burnup nuclear reactor fuel.« less

  9. Rare-earth elements in Egyptian granite by instrumental neutron activation analysis.

    PubMed

    El-Taher, A

    2007-04-01

    The mobilization of rare-earth elements (REEs) in the environment requires monitoring of these elements in environmental matrices, in which they are mainly present at trace levels. The similarity in REEs chemical behavior makes the separate determination of each element by chemical methods difficult; instrumental neutron activation analysis (INAA), based on nuclear properties of the elements to be determined, is a method of choice in trace analysis of REEs and related elements. Therefore, INAA was applied as a sensitive nondestructive analytical tool for the determination of REEs to find out what information could be obtained about the REEs of some Egyptian granite collected from four locations in Aswan area in south Egypt as follows wadi El-Allaqi, El-Shelal, Gabel Ibrahim Pasha and from Sehyel Island and to estimate the accuracy, reproducibility and detection limit of NAA method in case of the given samples. The samples were properly prepared together with standards and simultaneously irradiated in a neutron flux of 7 x 10(11)n/cm(2)s in the TRIGA Mainz research reactor facilities. The following elements have been determined: La, Ce, Nd, Sm, Eu, Yb and Lu. The gamma spectra was collected by HPGe detector and the analysis was done by means of computerized multichannel analyzer. The X-ray fluorescence (XRF) was also used. PMID:17208446

  10. Quantification of rare earth elements using laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Martin, Madhavi; Martin, Rodger C.; Allman, Steve; Brice, Deanne; Wymore, Ann; Andre, Nicolas

    2015-12-01

    A study of the optical emission as a function of concentration of laser-ablated yttrium (Y) and of six rare earth elements, europium (Eu), gadolinium (Gd), lanthanum (La), praseodymium (Pr), neodymium (Nd), and samarium (Sm), has been evaluated using the laser-induced breakdown spectroscopy (LIBS) technique. Statistical methodology using multivariate analysis has been used to obtain the sampling errors, coefficient of regression, calibration, and cross-validation of measurements as they relate to the LIBS analysis in graphite-matrix pellets that were doped with elements at several concentrations. Each element (in oxide form) was mixed in the graphite matrix in percentages ranging from 1% to 50% by weight and the LIBS spectra obtained for each composition as well as for pure oxide samples. Finally, a single pellet was mixed with all the elements in equal oxide masses to determine if we can identify the elemental peaks in a mixed pellet. This dataset is relevant for future application to studies of fission product content and distribution in irradiated nuclear fuels. These results demonstrate that LIBS technique is inherently well suited for the future challenge of in situ analysis of nuclear materials. These studies also show that LIBS spectral analysis using statistical methodology can provide quantitative results and suggest an approach in future to the far more challenging multielemental analysis of ~ 20 primary elements in high-burnup nuclear reactor fuel.

  11. Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

    SciTech Connect

    Martin, Madhavi Z; Fox, Dr. Richard V; Miziolek, Andrzej W; DeLucia, Frank C; Andre, Nicolas O

    2015-01-01

    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in real-world complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  12. Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

    SciTech Connect

    Martin, Madhavi Z; Fox, Dr. Richard V; Miziolek, Andrzej W; DeLucia, Frank C; Andre, Nicolas O

    2015-01-01

    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in realworld complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  13. Geochemical fractions of rare earth elements in soil around a mine tailing in Baotou, China

    NASA Astrophysics Data System (ADS)

    Wang, Lingqing; Liang, Tao

    2015-07-01

    Rare earth mine tailing dumps are environmental hazards because tailing easily leaches and erodes by water and wind. To assess the influence of mine tailing on the geochemical behavior of rare earth elements (REEs) in soil, sixty-seven surface soil samples and three soil profile samples were collected from different locations near China’s largest rare earth mine tailing. The total concentration of REEs in surface soils ranged from 156 to 5.65 × 104 mg·kg-1 with an average value of 4.67 × 103 mg·kg-1, which was significantly higher than the average value in China (181 mg·kg-1). We found obvious fractionation of both light and heavy REEs, which was supported by the North American Shale Composite (NASC) and the Post-Archean Average Australian Shale (PAAS) normalized concentration ratios calculated for selected elements (LaN/YbN, LaN/SmN and GdN/YbN). A slightly positive Ce anomaly and a negative Eu anomaly were also found. For all 14 REEs in soils, enrichment was intensified by the mine tailing sources and influenced by the prevailing wind.

  14. Spectral analysis of rare earth elements using laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Martin, Madhavi Z.; Fox, Robert V.; Miziolek, Andrzej W.; DeLucia, Frank C.; André, Nicolas

    2015-06-01

    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in realworld complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  15. Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

    SciTech Connect

    Madhavi Z. Martin; Robert V. Fox; Andrzej W. Miziolek; Frank C. DeLucia, Jr.; Nicolas Andre

    2001-05-01

    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in realworld complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  16. Geochemical fractions of rare earth elements in soil around a mine tailing in Baotou, China.

    PubMed

    Wang, Lingqing; Liang, Tao

    2015-01-01

    Rare earth mine tailing dumps are environmental hazards because tailing easily leaches and erodes by water and wind. To assess the influence of mine tailing on the geochemical behavior of rare earth elements (REEs) in soil, sixty-seven surface soil samples and three soil profile samples were collected from different locations near China's largest rare earth mine tailing. The total concentration of REEs in surface soils ranged from 156 to 5.65 × 10(4) mg·kg(-1) with an average value of 4.67 × 10(3) mg·kg(-1), which was significantly higher than the average value in China (181 mg·kg(-1)). We found obvious fractionation of both light and heavy REEs, which was supported by the North American Shale Composite (NASC) and the Post-Archean Average Australian Shale (PAAS) normalized concentration ratios calculated for selected elements (La(N)/Yb(N), La(N)/Sm(N) and Gd(N)/Yb(N)). A slightly positive Ce anomaly and a negative Eu anomaly were also found. For all 14 REEs in soils, enrichment was intensified by the mine tailing sources and influenced by the prevailing wind. PMID:26198417

  17. Geochemical fractions of rare earth elements in soil around a mine tailing in Baotou, China

    PubMed Central

    Wang, Lingqing; Liang, Tao

    2015-01-01

    Rare earth mine tailing dumps are environmental hazards because tailing easily leaches and erodes by water and wind. To assess the influence of mine tailing on the geochemical behavior of rare earth elements (REEs) in soil, sixty-seven surface soil samples and three soil profile samples were collected from different locations near China’s largest rare earth mine tailing. The total concentration of REEs in surface soils ranged from 156 to 5.65 × 104 mg·kg−1 with an average value of 4.67 × 103 mg·kg−1, which was significantly higher than the average value in China (181 mg·kg−1). We found obvious fractionation of both light and heavy REEs, which was supported by the North American Shale Composite (NASC) and the Post-Archean Average Australian Shale (PAAS) normalized concentration ratios calculated for selected elements (LaN/YbN, LaN/SmN and GdN/YbN). A slightly positive Ce anomaly and a negative Eu anomaly were also found. For all 14 REEs in soils, enrichment was intensified by the mine tailing sources and influenced by the prevailing wind. PMID:26198417

  18. Rare earth elements recycling from waste phosphor by dual hydrochloric acid dissolution.

    PubMed

    Liu, Hu; Zhang, Shengen; Pan, Dean; Tian, Jianjun; Yang, Min; Wu, Maolin; Volinsky, Alex A

    2014-05-15

    This paper is a comparative study of recycling rare earth elements from waste phosphor, which focuses on the leaching rate and the technical principle. The traditional and dual dissolution by hydrochloric acid (DHA) methods were compared. The method of dual dissolution by hydrochloric acid has been developed. The Red rare earth phosphor (Y0.95Eu0.05)2O3 in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce0.67Tb0.33MgAl11O19) and the Blue phosphor (Ba0.9Eu0.1MgAl10O17) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO2 are removed by washing. The insoluble matter is leached by the hydrochloric acid, followed by solvent extraction and precipitation (the DHA method). In comparison, the total leaching rate of the rare earth elements was 94.6% by DHA, which is much higher than 42.08% achieved by the traditional method. The leaching rate of Y, Eu, Ce and Tb reached 94.6%, 99.05%, 71.45%, and 76.22%, respectively. DHA can decrease the consumption of chemicals and energy. The suggested DHA method is feasible for industrial applications. PMID:24681591

  19. Enhanced phytoextraction of germanium and rare earth elements - a rhizosphere-based approach

    NASA Astrophysics Data System (ADS)

    Wiche, Oliver

    2016-04-01

    Germanium (Ge) and rare earth elements (REEs) are economically valuable raw materials that have become an integral part of our modern high tech society. While most of these elements are not actually rare in terms of general amounts in the earth's crust, they are rarely found in sufficient abundances in single locations for their mining to be economically viable. The average concentration of Ge in soils is estimated at 1.6 μg g-1. The REEs comprise a group of 16 elements including La, the group of lanthanides and Y that are abundant in the earth crust with concentrations varying from 35 μg g-1 (La), 40 μg g-1 (Nd), 6 μg g-1 (Gd) and 3.5 μg g-1 (Er) to 0.5 μg g-1 in Tm. Thus, a promising chance to improve supply of these elements could be phytomining. Unfortunately, bioavailability of Ge and REEs in soils appears to be low, in particular in neutral or alkaline soils. A sequential dissolution analysis of 120 soil samples taken from the A-horizons of soils in the area of Freiberg (Saxony, Germany) revealed that only 0.2% of total Ge and about 0.5% of La, Nd, Gd and Er of bulk concentrations were easily accessible by leaching with NH4-acetate (pH 7). Most of the investigated elements were bound to Fe-/Mn-oxides and silicates and were therefore only poorly available for plant uptake. Here we report an environmentally friendly approach for enhanced phytoextraction of Ge and REEs from soils using mixed cultures of plant species with efficient mechanisms for the acquisition of nutrients in the rhizosphere. The rhizosphere is characterized as the zone in soil sourrounding a plant root that consists of a gradient in chemical, physical and biological soil properties driven by rhizodeposits like carboxylates and protons. Some species like white lupin (Lupinus albus) are able to excrete large amounts of organic acid anions(predominantly citrate and malate) and show a particularly high potential for the acidification of the rhizosphere. In our experiments, mixed cultures

  20. Biological availability and environmental behaviour of Rare Earth Elements in soils of Hesse, Central Germany

    NASA Astrophysics Data System (ADS)

    Loell, M.; Duering, R.-A.; Felix-Henningsen, P.

    2009-04-01

    Rare earth elements (REEs) comprise a group of 17 transition metals with very similar chemical and physical properties. They include the elements scandium (Sc), yttrium (Y) and lanthanum (La) and the 14 elements (cerium to lutetium) that follow La in the periodic table. Their average abundance in the earth's crust varies from 0,01 to 0,02% so they are as common as Cu and Pb. Beside their widespread use in industry, REEs are applied in Chinese agriculture. Their beneficial effects both on crop yield and on animal production are reported in various investigations. As a result - by using microelement fertilisers and manure - REEs enter the pedosphere while their fate and behaviour in the environment up to now remains unexamined. The first aim of our investigation was to evaluate the concentration of REEs in agricultural used soils in central Germany (Hesse) by ICP-MS. In addition to their total concentration (aqua regia digestion) their bioavailable contents - determined by EDTA (potentially available fraction) and ammonium nitrate extraction (mobile fraction) - were analysed. The occurrence of the three REE fractions in different soils will be discussed and influencing soil properties (e.g. pH-value, content of clay and organic carbon) will be revealed. Additionally the uptake of REEs by grassland plants was determined and resulting transfer factors will be presented.

  1. Investigation of recovery and recycling of rare earth elements from waste fluorescent lamp phosphors

    NASA Astrophysics Data System (ADS)

    Eduafo, Patrick Max

    Characterization techniques and experimental measurements were used to evaluate a process for recycling rare earth elements (REEs) from spent fluorescent lamp phosphors. QEMSCAN analysis revealed that over 60% of the rare earth bearing minerals was less than 10 microm. A representative sample of the as-received feed contained 14.59 wt% total rare earth elements (TREE) and upon sieving to below 75 microm, the grade increased to 19.60 wt% REE with 98.75% recovery. Based on experimental work, a new process for extracting the chief REEs from end of life fluorescent lamps has been developed. The proposed flowsheet employs a three-stage leaching and precipitation process for selective extraction and recovery of the REEs. Hydrochloric acid was used as lixiviant in batch leach experiments on the phosphor powder. The maximum extraction obtained was 100% for both yttrium and europium under the following leaching conditions: 2.5 M HCl, 70°C, 1 hour, 180 g/L and 600 rpm. However, the solubility of cerium, lanthanum and terbium remained low at these conditions. Kinetic data of the leaching of yttrium and europium showed best fit to the logarithmic rate expression of the empirical model of leaching. Activation energy was calculated to be 77.49 kJ/mol for Y and 72.75 kJ/mol for Eu in the temperature range of 298 to 343 K. Precipitation tests demonstrate that at least 50% excess the stoichiometric amount of oxalic acid is needed to recover yttrium and europium efficiently to produce a pure (Y, Eu) mixed oxide. Total recovery of the REEs was achieved even at very low pH or without any base added. Over 99% pure mixed rare earth oxide at 99% recovery has been attained. An economic assessment of the developed process using operating and capital cost have be undertaken and based on the analysis of the three economic scenarios, two are economic and one is non-economic.

  2. Origin of Volatiles in Earth: Indigenous Versus Exogenous Sources Based on Highly Siderophile, Volatile Siderophile, and Light Volatile Elements

    NASA Technical Reports Server (NTRS)

    Righter, K.; Danielson, L.; Pando, K. M.; Marin, N.; Nickodem, K.

    2015-01-01

    Origin of Earth's volatiles has traditionally been ascribed to late accretion of material after major differentiation events - chondrites, comets, ice or other exogenous sources. A competing theory is that the Earth accreted its volatiles as it was built, thus water and other building blocks were present early and during differentiation and core formation (indigenous). Here we discuss geochemical evidence from three groups of elements that suggests Earth's volatiles were acquired during accretion and did not require additional sources after differentiation.

  3. NEW RARE EARTH ELEMENT ABUNDANCE DISTRIBUTIONS FOR THE SUN AND FIVE r-PROCESS-RICH VERY METAL-POOR STARS

    SciTech Connect

    Sneden, Christopher; Lawler, James E.; Den Hartog, Elizabeth A.; Cowan, John J.; Ivans, Inese I. E-mail: jelawler@wisc.edu E-mail: cowan@nhn.ou.edu

    2009-05-15

    We have derived new abundances of the rare earth elements Pr, Dy, Tm, Yb, and Lu for the solar photosphere and for five very metal-poor, neutron-capture r-process-rich giant stars. The photospheric values for all five elements are in good agreement with meteoritic abundances. For the low-metallicity sample, these abundances have been combined with new Ce abundances from a companion paper, and reconsideration of a few other elements in individual stars, to produce internally consistent Ba, rare earth, and Hf (56 {<=} Z {<=} 72) element distributions. These have been used in a critical comparison between stellar and solar r-process abundance mixes.

  4. On the origin of falling-tone chorus elements in Earth's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Breuillard, H.; Agapitov, O.; Artemyev, A.; Krasnoselskikh, V.; Le Contel, O.; Cully, C. M.; Angelopoulos, V.; Zaliznyak, Y.; Rolland, G.

    2014-12-01

    Generation of extremely/very low frequency (ELF/VLF) chorus waves in Earth's inner magnetosphere has received increased attention recently because of their significance for radiation belt dynamics. Though past theoretical and numerical models have demonstrated how rising-tone chorus elements are produced, falling-tone chorus element generation has yet to be explained. Our new model proposes that weak-amplitude falling-tone chorus elements can be generated by magnetospheric reflection of rising-tone elements. Using ray tracing in a realistic plasma model of the inner magnetosphere, we demonstrate that rising-tone elements originating at the magnetic equator propagate to higher latitudes. Upon reflection there, they propagate to lower L-shells and turn into oblique falling tones of reduced power, frequency, and bandwidth relative to their progenitor rising tones. Our results are in good agreement with comprehensive statistical studies of such waves, notably using magnetic field measurements from THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft. Thus, we conclude that the proposed mechanism can be responsible for the generation of weak-amplitude falling-tone chorus emissions.

  5. Study on the activated laser welding of ferritic stainless steel with rare earth elements yttrium

    NASA Astrophysics Data System (ADS)

    Wang, Yonghui; Hu, Shengsun; Shen, Junqi

    2015-10-01

    The ferritic stainless steel SUS430 was used in this work. Based on a multi-component activating flux, composed of 50% ZrO2, 12.09 % CaCO3, 10.43 % CaO, and 27.49 % MgO, a series of modified activating fluxes with 0.5%, 1%, 2%, 5%, 10%, 15%, and 20% of rare earth (RE) element yttrium (Y) respectively were produced, and their effects on the weld penetration (WP) and corrosion resistant (CR) property were studied. Results showed that RE element Y hardly had any effects on increasing the WP. In the FeCl3 spot corrosion experiment, the corrosion rates of almost all the samples cut from welded joints turned out to be greater than the parent metal (23.51 g/m2 h). However, there was an exception that the corrosion rate of the sample with 5% Y was only 21.96 g/m2 h, which was even better than parent metal. The further Energy Dispersive Spectrometer (EDS) test showed the existence of elements Zr, Ca, O, and Y in the molten slag near the weld seam while none of them were found in the weld metal, indicating the direct transition of element from activating fluxes to the welding seam did not exist. It was known that certain composition of activating fluxes effectively restrain the loss of Cr element in the process of laser welding, and as a result, the CR of welded joints was improved.

  6. Rare earth elements geochemistry in springs from Taftan geothermal area SE Iran

    NASA Astrophysics Data System (ADS)

    Shakeri, Ata; Ghoreyshinia, Sayedkazem; Mehrabi, Behzad; Delavari, Morteza

    2015-10-01

    Concentrations of rare earth elements (REEs) were determined in springs and andesitic-dacitic rocks of Taftan geothermal field. Hydrochemical results of major ions indicate that thermal springs are Na-SO4-Cl and Ca-SO4-Cl types. Concentrations of REEs are in ranges of 10- 4 to 1.2 and 49 to ~ 62 times of chondrite for springwater and rock samples, respectively. The thermal (STS and TTS) and the cold (APS) springs with low pH values exhibit a very high REE contents (0.64 to 3.15 mg/l). Saturation index indicates that Fe and Al phases can control dissolved REE concentration in FTS and PF cold springs. The speciation of REE complexes indicates dominant presence of LnSO4+ and free ion in the Taftan thermal springs. In APS cold spring with pH ~ 4, fluoride complexes are dominate over the free ion and sulfate species, while in PF and FTS cold springs with pH 6.4 and 7, respectively, carbonate complexes (LnCO3+) are predominant species. Chondrite-normalized pattern for the low-pH waters show very distinctive gull-wing patterns, characteristic feature of acid-sulfate geothermal systems, and are similar to those of the host rocks. Chemical characteristics of rare earth elements in spring and volcanic rock samples indicate that REEs are originated from the andesitic-dacitic host rocks. Whole-rock-normalized REE patterns and petrographic evidences show that rare earth elements leached mainly from marginal alteration of minerals and matrix decomposition in volcanic rocks. In chondrite-normalized REE patterns, significant negative Eu anomaly in the cold springs compare to the thermal and acidic springs indicates that alteration of plagioclase is more intense in the later, corresponding to increasing in temperature and acidic state of reactant water.

  7. Earth

    NASA Technical Reports Server (NTRS)

    Carr, M. H.

    1984-01-01

    The following aspects of the planet Earth are discussed: plate tectonics, the interior of the planet, the formation of the Earth, and the evolution of the atmosphere and hydrosphere. The Earth's crust, mantle, and core are examined along with the bulk composition of the planet.

  8. Equivalent Body Force Finite Elements Method and 3-D Earth Model Applied In 2004 Sumatra Earthquake

    NASA Astrophysics Data System (ADS)

    Qu, W.; Cheng, H.; Shi, Y.

    2015-12-01

    The 26 December 2004 Sumatra-Andaman earthquake with moment magnitude (Mw) of 9.1 to 9.3 is the first great earthquake recorded by digital broadband, high-dynamic-range seismometers and global positioning system (GPS) equipment, which recorded many high-quality geophysical data sets. The spherical curvature is not negligible in far field especially for large event and the real Earth is laterally inhomogeneity and the analytical results still are difficult to explain the geodetic measurements. We use equivalent body force finite elements method Zhang et al. (2015) and mesh the whole earth, to compute global co-seismic displacements using four fault slip models of the 2004 Sumatra earthquake provided by different authors. Comparisons of calculated co-seismic displacements and GPS show that the confidences are well in near field for four models, and the confidences are according to different models. In the whole four models, the Chlieh model (Chlieh et al., 2007) is the best as this slip model not only accord well with near field data but also far field data. And then we use the best slip model, Chlieh model to explore influence of three dimensional lateral earth structure on both layered spherically symmetric (PREM) and real 3-D heterogeneous earth model (Crust 1.0 model and GyPSuM). Results show that the effects of 3-D heterogeneous earth model are not negligible and decrease concomitantly with increasing distance from the epicenter. The relative effects of 3-D crust model are 23% and 40% for horizontal and vertical displacements, respectively. The effects of the 3-D mantle model are much smaller than that of 3-D crust model but with wider impacting area.

  9. Application of solid phase extraction procedures for rare earth elements determination in environmental samples.

    PubMed

    Pyrzynska, Krystyna; Kubiak, Anna; Wysocka, Irena

    2016-07-01

    Determination of rare earth elements in environmental samples requires often pre-concentration and separation step due to a low metal content and high concentration of the interfering matrix components. A solid phase extraction technique with different kind of solid sorbents offers a high enrichment factor, rapid phase separation and the possibility of its combination with various detection techniques used either in on-line or off-line mode. The recent developments in this area published over the last five years are presented and discussed in this paper. PMID:27154643

  10. Rare-Earth Elements in Lighting and Optical Applications and Their Recycling

    NASA Astrophysics Data System (ADS)

    Song, Xin; Chang, Moon-Hwan; Pecht, Michael

    2013-10-01

    Rare-earth elements (REEs) are used in lighting and optical applications to enable color and light adjustment, miniaturization, and energy efficiency. Common applications of REEs include phosphors for light-emitting diodes, lasers, and electronic video displays. This article reviews how REEs are widely used in these applications. However, supply constraints, including rising prices, environmental concerns over mining and refining processes, and China's control over the supply of the vast majority of REEs, are of concern for manufacturers. In view of these supply constraints, this article discusses ways for manufacturers of lighting and optical devices to identify potential substitutes and recycling methods for REEs.

  11. Influence of rare earth elements (Nd, Sm, Gd) on the physicochemical properties of ges crystal

    NASA Astrophysics Data System (ADS)

    Madatov, R. S.; Alekperov, A. S.; Magerramova, Dzh. A.

    2015-11-01

    Layered semiconductors (including GeS), which are widely used in modern electronics, are of great interest for researchers. New GeS-based devices have been developed for holographic recording, optical processing, and storage of information. In the last few years, American scientists have developed a unique GeS-based device that makes it possible to accumulate an immense amount of solar energy. The introduction of rare earth elements (REEs) facilitates the healing of metal and chalcogenide vacancies, removes polytypism, and enhances interlayer interaction.

  12. Extraction of rare earth elements from hydrate-phosphate precipitates of apatite processing

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    The features of extraction of rare earth elements (REE) were considered from hydrate-phosphate precipitates of REE of apatite processing by nitric acid technology. The preliminary purification of nitrate solution of REE from impurities of titanium, aluminum, iron, uranium and thorium was suggested to obtain stable solutions not forming precipitates. Washing the extract was recommended with the evaporated reextract that allows to obtain directly on the cascade of REE extraction the concentrated solutions suitable for the separation into groups by the extraction method. Technical decisions were suggested for the separation of REE in groups without the use of salting-out agent.

  13. An EDTA-β-cyclodextrin material for the adsorption of rare earth elements and its application in preconcentration of rare earth elements in seawater.

    PubMed

    Zhao, Feiping; Repo, Eveliina; Meng, Yong; Wang, Xueting; Yin, Dulin; Sillanpää, Mika

    2016-03-01

    The separation and recovery of Rare earth elements (REEs) from diluted aqueous streams has attracted great attention in recent years because of ever-increasing REEs demand. In this study, a green synthesized EDTA-cross-linked β-cyclodextrin (EDTA-β-CD) biopolymer was prepared and employed in adsorption of aqueous REEs, such as La(III), Ce(III), and Eu(III). EDTA acts not only as cross-linker but also as coordination site for binding of REEs. The adsorption properties for the adsorption of REEs by varying experimental conditions were carried out by batch tests. The kinetics results revealed that the surface chemical sorption and the external film diffusion were the rate-determining steps of the adsorption process. The obtained maximum adsorption capacities of EDTA-β-CD were 0.343, 0.353, and 0.365mmolg(-1) for La(III), Ce(III) and Eu(III), respectively. Importantly, the isotherms fitted better to Langmuir than Freundlich and Sips models, suggesting a homogenous adsorption surface for REEs on the adsorbent. Moreover, the multi-component adsorption, which was modeled by extended Sips isotherms, revealed adsorbent's selectivity to Eu(III). More significantly, the successful recoveries of the studied ions from tap water and seawater samples makes EDTA-β-CD a promising sorbent for the preconcentration of REEs from diluted aqueous streams. PMID:26674238

  14. Partitioning of light lithophile elements during basalt eruptions on Earth and application to Martian shergottites

    NASA Astrophysics Data System (ADS)

    Edmonds, Marie

    2015-02-01

    An enigmatic record of light lithophile element (LLE) zoning in pyroxenes in basaltic shergottite meteorites, whereby LLE concentrations decrease dramatically from the cores to the rims, has been interpreted as being due to partitioning of LLE into a hydrous vapor during magma ascent to the surface on Mars. These trends are used as evidence that Martian basaltic melts are water-rich (McSween et al., 2001). Lithium and boron are light lithophile elements (LLE) that partition into volcanic minerals and into vapor from silicate melts, making them potential tracers of degassing processes during magma ascent to the surface of Earth and of other planets. While LLE degassing behavior is relatively well understood for silica-rich melts, where water and LLE concentrations are relatively high, very little data exists for LLE abundance, heterogeneity and degassing in basaltic melts. The lack of data hampers interpretation of the trends in the shergottite meteorites. Through a geochemical study of LLE, volatile and trace elements in olivine-hosted melt inclusions from Kilauea Volcano, Hawaii, it can be demonstrated that lithium behaves similarly to the light to middle rare Earth elements during melting, magma mixing and fractionation. Considerable heterogeneity in lithium and boron is inherited from mantle-derived primary melts, which is dominant over the fractionation and degassing signal. Lithium and boron are only very weakly volatile in basaltic melt erupted from Kilauea Volcano, with vapor-melt partition coefficients <0.1. Degassing of LLE is further inhibited at high temperatures. Pyroxene and associated melt inclusion LLE concentrations from a range of volcanoes are used to quantify lithium pyroxene-melt partition coefficients, which correlate negatively with melt H2O content, ranging from 0.13 at low water contents to <0.08 at H2O contents >4 wt%. The observed terrestrial LLE partitioning behavior is extrapolated to Martian primitive melts through modeling. The zoning

  15. Geochemistry of rare earth elements in Permian coals from the Huaibei Coalfield, China

    USGS Publications Warehouse

    Zheng, Lingyun; Liu, Gaisheng; Chou, C.-L.; Qi, C.; Zhang, Y.

    2007-01-01

    The rare earth elements (REEs) in coals are important because of: (a) REE patterns can be an indicator of the nature of source rocks of the mineral matter as well as sedimentary environments; (b) REEs abundance in coal may have industrial-significance. In this study, a total of thirty-four samples of Permian coal, partings, roof, and floor were collected from the Huaibei Coalfield, Anhui Province, China. Abundances of rare earth elements (REEs) and other elements in the samples were determined by inductively coupled-plasma mass spectrometry (ICP-MS) and inductively coupled-plasma atomic emission spectrometry (ICP-AES). The results show that the REEs are enriched in coals in the Huaibei Coalfield as compared with Chinese and U.S. coals and the world coal average. Coals in the Lower Shihezi Formation (No. 7, 5, and 4 Coals) and Upper Shihezi Formation (No. 3) have higher REE abundances than the coals in Shanxi Formation (No. 10). Magmatic intrusion resulted in high enrichment of REEs concentrations in No. 5 and 7 Coals. The REE abundances are positively correlated with the ash content. The mineral matter in these coals is mainly made up of clay minerals and carbonates. The REEs are positively correlated with lithophile elements including Si, Al, Ti, Fe, and Na, which are mainly distributed in clay minerals, indicating that REEs are contained mainly in clay minerals. The REE abundances in coals normalized by the ash are higher than that in partings. REEs abundances of coals cannot be accounted for by the REE content in the mineral matter, and some REEs associated with organic matter in coals. ?? 2007 Elsevier Ltd. All rights reserved.

  16. Nuclear activation method and apparatus for detecting and quantifying earth elements

    SciTech Connect

    Carroll, J.F.

    1993-08-17

    A method is described for characterizing at least one activated element in an earth formation surrounding a borehole, comprising the steps of: (a) displacing in said borehole a sonde comprising a neutron source and at least two gamma ray detectors longitudinally spaced from said source, while irradiating said formation with neutrons of sufficient energy to interact with said element according to the activation reaction; (b) detecting and counting at each detector the gamma rays resulting from the activation of atoms of said element; (c) determining, at each depth, the number of gamma ray counts detected during the time period defined by the time instants when respectively said source and said detectors pass that depth, said determination of gamma ray counts being made for each detector at each depth; (d) establishing a relationship, for each depth, between the counts from the respective detectors for that depth and the corresponding time instants when the corresponding detector passes that depth; and (e) deriving from said relationship at least one characteristic of said element.

  17. Rare earth elements in soils from selected areas on the Island of Hawaii

    SciTech Connect

    Barnard, W.M.; Halbig, J.B.

    1985-07-01

    Fifty soil samples for the wet, windward (east) side and dry, leeward (west) side of the Island of Hawaii were analyzed for La, Ce, Sm, Eu, Yb, and Lu by neutron activation/gamma-ray spectroscopic analysis. Data on concentrations in each sample are listed and analyzed statistically for soil samples collected from the western slope of Kohala Mountain, the western coastal plain of Mauna Kea, and the Northeastern coastal plain of Maunal Loa. Rare earth element (REE) concentrations are two to six times greater in soils from the western, dry side of the island, and good statistical correlation is exhibited among the samples for pairs of individual REEs. In the organic-rich soils of the east side, correlations are poor but are markedly improved when sample weights are adjusted for weight due to organic matter and water in soil colloids. If the mean compositions of selected rock samples from the Hawaii Reference Suite are representative of the compositions of the parent materials, REEs in the soils are moderately enriched (up to two times, based on oven-dry weights). Rare earth element concentrations in the island's western soils are as much as two times greater than the mean REE values of common sedimentary rocks worldwide; however, they are well within the concentration ranges of soils of continental origin. The eastern soils tend to have less La and Ce, but similar amounts of the middle and heavy REEs.

  18. Rare earth elements in sediments of the Vigo Ria, NW Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Prego, Ricardo; Caetano, Miguel; Vale, Carlos; Marmolejo-Rodríguez, Judith

    2009-04-01

    The abundance and distribution of rare earth elements (REE) and their signatures in the Vigo Ria were studied from 50 samples of surface sediments and related to the geological formation in its watershed. The total amount of REE in the Ria is heterogeneous. It ranges from 220 mg kg -1 in the southern middle Ria margin in the vicinity of the Galiñeiro geological shore complex, which contains REE-enriched minerals, to 2 mg kg -1 near the Ria mouth due to dilution with high levels of carbonated biogenic particles (31% of Ca). Rare earth elements of the Ria sediments are considerably enriched in light-REE relative to heavy-REE (a LREE/HREE ratio of 9.7±1.6) and also show a slightly negative Eu-anomaly. Low European shale normalised REE patterns were distinguished in the innermost sediments of Vigo Ria, but were not correlated with Al. This suggests a minor contribution of REE from upstream freshwater inputs to the sediments in the middle Vigo Ria zone. Normalised REE ratios in the middle Ria imply that fine particles enriched in REE may be exported from the Ria to shelf mud patches and REE can be useful as sediment tracers of Ria input on the shelf.

  19. Rare earth element components in atmospheric particulates in the Bayan Obo mine region.

    PubMed

    Wang, Lingqing; Liang, Tao; Zhang, Qian; Li, Kexin

    2014-05-01

    The Bayan Obo mine, located in Inner Mongolia, China, is the largest light rare earth body ever found in the world. The research for rare earth elements (REEs) enrichment in atmospheric particulates caused by mining and ore processing is fairly limited so far. In this paper, atmospheric particulates including total suspended particulate (TSP) matter and particles with an equivalent aerodynamic diameter less than 10 μm (PM10) were collected around the Bayan Obo mine region, in August 2012 and March 2013, to analyze the levels and distributions of REEs in particles. The total concentrations of REEs for TSP were 149.8 and 239.6 ng/m(3), and those for PM10 were 42.8 and 68.9 ng/m(3), in August 2012 and March 2013, respectively. Enrichment factor was calculated for all 14 REEs in the TSP and PM10 and the results indicated that REEs enrichment in atmosphere particulates was caused by anthropogenic sources and influenced by the strong wind in springtime. The spatial distribution of REEs in TSP showed a strong gradient concentration in the prevailing wind direction. REE chondrite normalized patterns of TSP and PM10 were similar and the normalized curves inclined to the right side, showing the conspicuous fractionation between the light REEs and heavy REE, which supported by the chondrite normalized concentration ratios calculated for selected elements (La(N)/Yb(N), La(N)/Sm(N), Gd(N)/Yb(N)). PMID:24657942

  20. Seawater rare-earth element patterns preserved in apatite of Pennsylvanian conodonts?

    NASA Astrophysics Data System (ADS)

    Bright, Camomilia A.; Cruse, Anna M.; Lyons, Timothy W.; MacLeod, Kenneth G.; Glascock, Michael D.; Ethington, Raymond L.

    2009-03-01

    Past workers have used rare-earth element patterns recorded in biogenic apatite as proxies for original seawater chemistry. To explore the potency of this approach, we analyzed Pennsylvanian conodonts from limestones, gray shales, and black shales of the Fort Scott and Pawnee formations (Desmoinesian) and Swope and Dennis formations (Missourian) in Kansas, Missouri, and Iowa, U.S.A. Analysis of individual platform conodonts from seven taxa using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) revealed a consistent enrichment in the middle rare-earth elements (MREE). Analogous MREE enrichment has been observed in authigenic apatite and bulk samples of phosphate-rich black shales from the same formations. Importantly, however, phosphate-depleted shales intimately associated with the P-rich intervals are relatively depleted in MREE. These antithetic patterns argue convincingly for secondary migration from the bulk sediment into the phosphate, and the extent of MREE enrichment in the conodonts is correlated positively with the total REE content. MREE enrichment in conodonts does not vary systematically as a function of lithology, stratigraphic level, conodont genus, geographic location, or with independent estimates of paleoredox conditions in the bottom waters. Collectively, these results argue for postmortem (diagenetic) REE uptake resulting in a pronounced (and progressive) MREE enrichment. Any cerium anomalies, if initially present, were masked by diagenetic uptake of REE. Paleoenvironmental interpretations of conodont REE, particularly for samples exhibiting MREE enrichment, should therefore be viewed with caution.

  1. The History and Use of Our Earth's Chemical Elements: A Reference Guide (by Robert E. Krebs)

    NASA Astrophysics Data System (ADS)

    Bracken, Reviewed By Jeffrey D.

    1999-04-01

    Greenwood Press: Westport, CT, 1998. 282 pp + 25 pp glossary + 37 pp index. 15.9 x 24.1 cm. ISBN 0-313-30123-9. $39.95. This book is an excellent resource for chemical educators at the high school and college levels. The format of the text is consistent and the writing style is clear and concise, making it ideally suited for student use also. The first three chapters serve to introduce the reader to a brief history of chemistry, early models of the atom, and the development of the periodic table. Names of the contributing scientists are mentioned whenever necessary, but the overall purpose of these introductory chapters is simply to lay a foundation for the subsequent seven chapters. A complete glossary of important scientific terms mentioned in the text should allow beginning students to use this book without feeling overwhelmed. Each entry for the 112 elements contains the following information: elemental symbol, atomic number, period, common valence, atomic weight, natural state, common isotopes, properties, characteristics, abundance, natural sources, history, common uses and compounds, and safety hazards. This information is well organized, with clear headings and separate sections making the book extremely user-friendly. Readers can easily obtain the information they desire without having to skim the full entry for a chosen element. One very nice feature of this book is that the elements entries are arranged by their locations in the periodic table. For example, chapter 4 contains the alkali metals and alkaline earth metals. This organizational scheme allows one to quickly see the patterns and trends within groups of elements. This format is significantly better than arranging the elements in alphabetical order, which places the entry for sodium far removed from the entries for lithium and potassium. I would highly recommend this book to high school teachers and college chemistry professors. It is well written and is an excellent source of information for

  2. Toward understanding early Earth evolution: Prescription for approach from terrestrial noble gas and light element records in lunar soils

    PubMed Central

    Ozima, Minoru; Yin, Qing-Zhu; Podosek, Frank A.; Miura, Yayoi N.

    2008-01-01

    Because of the almost total lack of geological record on the Earth's surface before 4 billion years ago, the history of the Earth during this period is still enigmatic. Here we describe a practical approach to tackle the formidable problems caused by this lack. We propose that examinations of lunar soils for light elements such as He, N, O, Ne, and Ar would shed a new light on this dark age in the Earth's history and resolve three of the most fundamental questions in earth science: the onset time of the geomagnetic field, the appearance of an oxygen atmosphere, and the secular variation of an Earth–Moon dynamical system. PMID:19001263

  3. Rare earth element distributions in recent and fossil apatite: implications for paleoceanography and stratigraphy

    SciTech Connect

    Wright, J.

    1985-01-01

    Rare earth element (REE) distributions in biogenic apatite were determined in over 200 samples from Cambrian to the Recent. Nondestructive instrumental neutron activation analysis techniques were adapted for analysis of low-mass microfossil samples. Tests for chemical contamination, interspecies, interlaboratory and interexperiment variations show that there is no fractionation of REE, so that ratios of rare earths are consistent throughout the entire group of samples. The REE signature of biogenic apatite is acquired after deposition but only at the sediment-water interface and is characteristic of the redox state of the environment of deposition. This original environmental signature is retained through subsequent burial and diagenesis. Cerium has been shown to be the rare earth element that is sensitive to oxidation-reduction variations in marine waters. This cerium variation is stated mathematically and called Ce/sub anom/. Comparison of Ce/sub anom/ in fish debris from different modern redox environments shows that values > -0.10 occur in fish debris deposited under reducing conditions, whereas Ce/sub anom/ values <-0.10 are obtained under oxidizing conditions. Paleoredox studies of Ce/sub anom/ of fossil apatite of conodonts, fish debris and inarticulate brachiopods indicate that significant shifts in the overall redox balance of seawater occurred in ancient oceans. Cambrian through Silurian seas were dominated by anoxia, followed by a gradual change to oxidizing conditions in the Devonian. Oceans remained generally oxidizing throughout the Carboniferous and Lower Permian. In the Upper Permian and Lower Triassic anoxic conditions were again prevalent. This was followed by a return to an oxidizing oceanic environment in the Upper Triassic.

  4. Composition of the earth's upper mantle-I. Siderophile trace elements in ultramafic nodules

    USGS Publications Warehouse

    Morgan, J.W.; Wandless, G.A.; Petrie, R.K.; Irving, A.J.

    1981-01-01

    Seven siderophile elements (Au, Ge, Ir, Ni, Pd, Os, Re) were determined by radiochemical neutron activation analysis in 19 ultramafic rocks, which are spinel lherzollites-xenoliths from North and Central America, Hawaii and Australia, and garnet Iherzolitexenoliths from Lesotho. Abundances of the platinum metals are very uniform in spinel lherzolites averaging 3.4 ?? 1.2 ppb Os, 3.7 ?? 1.1 ppb Ir, and 4.6 ?? 2.0 ppb Pd. Sheared garnet lherzolite PHN 1611 has similar abundances of these elements, but in 4 granulated garnet lherzolites, abundances are more variable. In all samples, the Pt metals retain cosmic ( Cl-chondrite) ratios. Abundances of Au and Re vary more than those of Pt metals, but the Au/Re ratio remains close to the cosmic value. The fact that higher values of Au and Re approach cosmic proportions with respect to the Pt metals, suggests that Au and Re have been depleted in some ultramafic rocks from an initially chondrite-like pattern equivalent to about 0.01 of Cl chondrite abundances. The relative enrichment of Au and Re in crustal rocks is apparently the result of crust-mantle fractionation and does not require a special circumstance of core-mantle partitioning. Abundances of moderately volatile elements Ni, Co and Ge are very uniform in all rocks, and are much higher than those of the highly siderophile elements Au, Ir, Pd, Os and Re. When normalized to Cl chondrites, abundances of Ni and Co are nearly identical, averaging 0.20 ?? 0.02 and 0.22 ?? 0.02, respectively; but Ge is only 0.027 ?? 0.004. The low abundance of Ge relative to Ni and Co is apparently a reflection of the general depletion of volatile elements in the Earth. The moderately siderophile elements cannot be derived from the same source as the highly siderophile elements because of the marked difference in Cl chondrite-normalized abundances and patterns. We suggest that most of the Ni, Co and Ge were enriched in the silicate by the partial oxidation of pre-existing volatile-poor Fe

  5. Earth Observatory Satellite system definition study. Report no. 5: System design and specifications. Part 1: Observatory system element specifications

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The performance, design, and quality assurance requirements for the Earth Observatory Satellite (EOS) Observatory and Ground System program elements required to perform the Land Resources Management (LRM) A-type mission are presented. The requirements for the Observatory element with the exception of the instruments specifications are contained in the first part.

  6. Effect of the addition of low rare earth elements (lanthanum, neodymium, cerium) on the biodegradation and biocompatibility of magnesium.

    PubMed

    Willbold, Elmar; Gu, Xuenan; Albert, Devon; Kalla, Katharina; Bobe, Katharina; Brauneis, Maria; Janning, Carla; Nellesen, Jens; Czayka, Wolfgang; Tillmann, Wolfgang; Zheng, Yufeng; Witte, Frank

    2015-01-01

    Rare earth elements are promising alloying element candidates for magnesium alloys used as biodegradable devices in biomedical applications. Rare earth elements have significant effects on the high temperature strength as well as the creep resistance of alloys and they improve magnesium corrosion resistance. We focused on lanthanum, neodymium and cerium to produce magnesium alloys with commonly used rare earth element concentrations. We showed that low concentrations of rare earth elements do not promote bone growth inside a 750 μm broad area around the implant. However, increased bone growth was observed at a greater distance from the degrading alloys. Clinically and histologically, the alloys and their corrosion products caused no systematic or local cytotoxicological effects. Using microtomography and in vitro experiments, we could show that the magnesium-rare earth element alloys showed low corrosion rates, both in in vitro and in vivo. The lanthanum- and cerium-containing alloys degraded at comparable rates, whereas the neodymium-containing alloy showed the lowest corrosion rates. PMID:25278442

  7. Assessing the utility of trace and rare earth elements as biosignatures in microbial iron oxyhydroxides

    NASA Astrophysics Data System (ADS)

    Heim, Christine; Simon, Klaus; Ionescu, Danny; Reimer, Andreas; De Beer, Dirk; Quéric, Nadia-Valérie; Reitner, Joachim; Thiel, Volker

    2015-02-01

    Microbial iron oxyhydroxides are common deposits in natural waters, recent sediments and mine drainage systems and often contain significant accumulations of trace and rare earth elements (TREE). TREE patterns are widely used to characterize minerals and rocks, and to elucidate their evolution and origin. Whether and which characteristic TREE signatures distinguish between a biological and an abiological origin of iron minerals is still not well understood. Long-term flow reactor studies were performed in the Äspö Hard Rock Laboratory to investigate the development of microbial mats dominated by iron-oxidizing bacteria, namely Mariprofundus sp. and Gallionella sp. The experiments investigated the accumulation and fractionation of TREE under controlled conditions and enabled us to assess potential biosignatures evolving within the microbial iron oxyhydroxides. Concentrations of Be, Y, Zn, Zr, Hf, W, Th, Pb, and U in the microbial mats were 1e3- to 1e5-fold higher than in the feeder fluids whereas the rare earth elements and Y (REE+Y) contents were 1e4 and 1e6 fold enriched. Except for a hydrothermally induced Eu anomaly, the normalized REE+Y patterns of the microbial iron oxyhydroxides were very similar to published REE+Y distributions of Archaean Banded Iron Formations. The microbial iron oxyhydroxides from the flow reactors were compared to iron oxyhydroxides that were artificially precipitated from the same feeder fluid. These abiotic and inorganic iron oxyhydroxides show the same REE+Y distribution patterns. Our results indicate that the REE+Y mirror quite exactly the water chemistry, but they do not allow to distinguish microbially mediated from inorganic iron precipitates. All TREE studied showed an overall similar fractionation behavior in biogenic, abiotic and inorganic iron oxyhydroxides. Exceptions are Ni and Tl, which were only accumulated in the microbial iron oxyhydroxides and may point to a potential usage of these elements as microbial biosignatures.

  8. Levels of platinum group elements and rare-earth elements in wild mushroom species growing in Poland.

    PubMed

    Mleczek, Mirosław; Niedzielski, Przemysław; Kalač, Pavel; Siwulski, Marek; Rzymski, Piotr; Gąsecka, Monika

    2016-01-01

    Due to limited data-describing abilities of mushrooms to accumulate platinum group elements (PGEs) and rare-earth elements (REEs), the aim of this study was to determine, by inductively coupled plasma optical emission spectrometry followed by microwave-assisted sample digestion by nitric acid, the content of these elements in 20 mushroom species (10 above ground and 10 growing on wood), mostly edible, collected near a busy trunk road. The highest content of PGEs in above-ground mushroom species was observed in Lepista gilva and Suillus bovinus fruit bodies (0.38 ± 0.05 and 0.37 ± 0.03 mg kg(-1) DW, respectively), while in mushrooms growing on wood, the highest content was observed in Pleurotus ostreatus (0.35 ± 0.04 mg kg(-1) DW). The mean content of PGEs for both these groups was 0.23 ± 0.08 and 0.26 ± 0.07 mg kg(-1) DW, respectively. The highest content of REEs in Suillus luteus and Tricholoma equestra was 5.03 ± 0.50 and 2.18 ± 0.56 mg kg(-1) DW, respectively, but within mushrooms growing on wood in Ganoderma applanatum fruiting bodies it was 4.19 ± 0.78 mg kg(-1) DW. Mean contents of REEs were 1.39 ± 1.21 and 1.61 ± 0.97 mg kg(-1) DW in above-ground species and species growing on wood, respectively. Generally, the group of mushroom species growing on wood was capable of slightly higher accumulation of both REEs and PGEs. No limits have been established for both the groups until now. PMID:26515437

  9. Siderophile and chalcophile element abundances in oceanic basalts, Pb isotope evolution and growth of the earth's core

    NASA Technical Reports Server (NTRS)

    Newsom, H. E.; White, W. M.; Jochum, K. P.; Hofmann, A. W.

    1986-01-01

    The hypothesis that the mantle Pb isotope ratios reflect continued extraction of Pb into the earth's core over geologic time is evaluated by studying the depeletion of chalcophile and siderophile elements in the mantle. Oceanic basalt samples are analyzed in order to determine the Pb, Sr, and Nd isotropic compositions and the abundances of siderophile and chalcophile elements and incompatible lithophile elements. The data reveal that there is no systematic variation of siderophile or chalcophile element abundances relative to abundances of lithophile elements and the Pb/Ce ratio of the mantle is constant. It is suggested that the crust formation involves nonmagmatic and magmatic processes.

  10. Chemical properties of rare earth elements in typical medical waste incinerator ashes in China.

    PubMed

    Zhao, Lijuan; Zhang, Fu-Shen; Zhang, Jingxin

    2008-10-30

    Medical waste (MW) ashes from different types of MW incinerators were examined to detect the characteristics and environmental impact of rare earth elements (REEs). The results showed that total REE contents in the ash samples ranged from 10.2 to 78.9 mg/kg. REEs in bottom ash were apparently higher than those in fly ash. Average REE contents in the ashes followed the sequence of Ce>La>Nd>Y>Gd>Pr>Sm>Dy>Er>Yb>Ho>Eu>Tb>Lu>Tm. Some of the elements, such as Sm, Dy, Ho, Er, Yb in the ash samples were in normal or nearly normal distribution, but Y, La, Ce, Pr, Nd, Eu, Gd, Tb, Tm, Lu were not normally distributed, indicating some of the ash samples were enriched with these elements. Crust-normalized REE patterns indicated that two types of the MW ashes were obviously enriched with Gd and La. Sequential extraction results showed that REEs in the ash mainly presented as residual fraction, while exchangeable and carbonate fractions were relatively low. DTPA- and EDTA-extraction tests indicated that REEs in the MW ashes were generally in low bioavailability. PMID:18329796

  11. 'Nano' Morphology and Element Signatures of Early Life on Earth: A New Tool for Assessing Biogenicity

    NASA Technical Reports Server (NTRS)

    Oehler, D. Z.; Mostefaoui, S.; Meibom, A.; Selo, M.; McKay, D. S.; Robert, F.

    2006-01-01

    The relatively young technology of NanoSIMS is unlocking an exciting new level of information from organic matter in ancient sediments. We are using this technique to characterize Proterozoic organic material that is clearly biogenic as a guide for interpreting controversial organic structures in either terrestrial or extraterrestrial samples. NanoSIMS is secondary ion mass spectrometry for trace element and isotope analysis at sub-micron resolution. In 2005, Robert et al. [1] combined NanoSIMS element maps with optical microscopic imagery in an effort to develop a new method for assessing biogenicity of Precambrian structures. The ability of NanoSIMS to map simultaneously the distribution of organic elements with a 50 nm spatial resolution provides new biologic markers that could help define the timing of life s development on Earth. The current study corroborates the work of Robert et al. and builds on their study by using NanoSIMS to map C, N (as CN), S, Si and O of both excellently preserved microfossils and less well preserved, non-descript organics in Proterozoic chert from the ca. 0.8 Ga Bitter Springs Formation of Australia.

  12. Rare earth element geochemistry and petrogenesis of miles (IIE) silicate inclusions

    NASA Astrophysics Data System (ADS)

    Hsu, Weibiao

    2003-12-01

    An ion probe study of rare earth element (REE) geochemistry of silicate inclusions in the Miles IIE iron meteorite was carried out. Individual mineral phases among inclusions have distinct REE patterns and abundances. Most silicate grains have homogeneous REE abundances but show considerable intergrain variations between inclusions. A few pyroxene grains display normal igneous REE zoning. Phosphates (whitlockite and apatite) are highly enriched in REEs (50 to 2000 × CI) with a relatively light rare earth element (LREE)-enriched REE pattern. They usually occurred near the interfaces between inclusions and Fe host. In Miles, albitic glasses exhibit two distinctive REE patterns: a highly fractionated LREE-enriched (CI normalized La/Sm ˜15) pattern with a large positive Eu anomaly and a relatively heavy rare earth element (HREE)-enriched pattern (CI-normalized Lu/Gd ˜4) with a positive Eu anomaly and a negative Yb anomaly. The glass is generally depleted in REEs relative to CI chondrites. The bulk REE abundances for each inclusion, calculated from modal abundances, vary widely, from relatively depleted in REEs (0.1 to 3 × CI) with a fractionated HREE-enriched pattern to highly enriched in REEs (10 to 100 × CI) with a relatively LREE-enriched pattern. The estimated whole rock REE abundances for Miles are at ˜ 10 × CI with a relatively LREE-enriched pattern. This implies that Miles silicates could represent the product of a low degree (˜10%) partial melting of a chondritic source. Phenocrysts of pyroxene in pyroxene-glassy inclusions were not in equilibrium with coexisting albitic glass and they could have crystallized from a parental melt with REEs of ˜ 10 × CI. Albitic glass appears to have formed by remelting of preexisting feldspar + pyroxene + tridymite assemblage. Yb anomaly played an important role in differentiation processes of Miles silicate inclusions; however, its origin remains unsolved. The REE data from this study suggest that Miles, like

  13. Insights into early Earth from Barberton komatiites: Evidence from lithophile isotope and trace element systematics

    NASA Astrophysics Data System (ADS)

    Puchtel, I. S.; Blichert-Toft, J.; Touboul, M.; Walker, R. J.; Byerly, G. R.; Nisbet, E. G.; Anhaeusser, C. R.

    2013-05-01

    Major, minor, and lithophile trace element abundances and Nd and Hf isotope systematics are reported for two sets of remarkably fresh, by Archean standards, samples of komatiitic lavas from the 3.48 Ga Komati and the 3.27 Ga Weltevreden Formations of the Barberton Greenstone Belt (BGB) in South Africa. These data are used to place new constraints on the thermal history of the early Archean mantle, on the timing of its differentiation, and on the origin and chemical nature of early mantle reservoirs and their evolution through time. Projected moderate to strong depletions of highly incompatible lithophile trace elements and water in the mantle sources of both komatiite systems, combined with the partitioning behavior of V during lava differentiation, are consistent with anhydrous conditions during generation of the komatiite magmas. Komati and Weltevreden lavas are inferred to have erupted with temperatures of ∼1600 °C, and, thus, represent the hottest known lavas on Earth. The calculated mantle potential temperatures of ∼1800 °C for both komatiite systems are 150-200 °C higher than those of contemporary ambient mantle. Combined, these observations are consistent with the origin of these BGB komatiite magmas in mantle plumes in the lower mantle. New Sm-Nd and Lu-Hf isotopic data allow precise determination of initial ε143Nd = +0.46 ± 0.10 and +0.50 ± 0.11 and initial ε176Hf = +1.9 ± 0.3 and +4.7 ± 0.8 for the Komati and the Weltevreden system komatiites, respectively. These positive initial values reflect prior fractionation of Sm/Nd and Lu/Hf in the mantle early in Earth history. Conversely, μ142Nd values are 0.0 ± 2.4 and +2.2 ± 4.1 for the Komati and the Weltevreden systems, respectively. These values overlap, within uncertainties, those of modern terrestrial rocks, thus, limiting the magnitudes of possible Sm/Nd fractionations generated by early Earth processes in the sources of these rocks. Combined 142,143Nd and Hf isotope and lithophile trace

  14. Strontium isotopes and rare-earth element geochemistry of hydrothermal carbonate deposits from Lake Tanganyika, East Africa

    SciTech Connect

    Barrat, J.A.; Boulegue, J.; Tiercelin, J.J.; Lesourd, M.

    2000-01-01

    At Cape Banza (North Tanganyika Lake), fluids and aragonite chimneys have been collected many times since the discovery of this sublacustrine field in 1987. This sampling has been investigated here for the Sr isotopic compositions and the rare-earth element features of the carbonates and a few fluid samples. The {sup 87}Sr/{sup 86}Sr ratios of the chimneys indicate that they have precipitated from a mixture of lake water (more than 95%) and hydrothermal fluids. No zoning in the chimneys was detected with the Sr data. For the rare-earth elements, the situation is more complex. The external walls of the chimneys are rare-earth-element-poor (La {approx} 500 ppb, Yb {approx} 200 ppb, La/Yb = 2 to 3.4). Their shale normalized rare-earth element patterns suggest that they are in equilibrium with the inferred carbonate-depositing fluids. The rare-earth element concentrations of the internal walls of the chimneys are significantly light rare earth elements (LREE)-enriched with La contents sometimes up to 5 ppm. The authors suggest that they contain more vent-fluid rare-earth elements than the external wall samples, possibly adsorbed on the surface of growing crystals or simply hosted by impurities. It was not possible to constrain the nature of these phases, but the variations of the compositions of the internal wall materials of the active chimneys with time, as well as data obtained on an inactive chimney indicate that this rare-earth element excess is mobile. Partition coefficients were calculated between the external wall aragonite and carbonate-depositing fluid. The results are strikingly similar to the values obtained by Sholkovitz and Shen (1995) on coral aragonite, and suggest that there is no significant biologic effect on the incorporation of rare-earth elements into coral aragonite and that the various carbonate complexes involved Me(CO{sub 3}{sup +}) complexes are the main LREE carriers in seawater instead of Me(CO{sub 3}){sub 2}{sup {minus}} in Banza fluids

  15. Naturally occurring radionuclides and rare earth elements in weathered Japanese soil samples

    NASA Astrophysics Data System (ADS)

    Sahoo, Sarata; Hosoda, Masahiro; Prasad, Ganesh; Takahashi, Hiroyuki; Sorimachi, Atsuyuki; Ishikawa, Tetsuo; Tokonami, Shinji; Uchida, Shigeo

    2013-08-01

    The activity concentrations of 226Ra and 228Ac in weathered Japanese soils from two selected prefectures have been measured using a γ-ray spectroscopy system with high purity germanium detector. The uranium, thorium, and rare earth elements (REEs) concentrations were determined from the same soil samples using inductively coupled plasma mass spectrometry (ICP-MS). For example, granitic rocks contain higher amounts of U, Th, and light REEs compared to other igneous rocks such as basalt and andesites. Therefore, it is necessary to understand the interaction between REEs and nature of soils since soils are complex heterogeneous mixture of organic and inorganic solids, water, and gases. In this paper, we will discuss about distribution pattern of 238U and 232Th along with REEs in soil samples of weathered acid rock (granite) collected from two prefectures of Japan: Hiroshima and Miyagi.

  16. Distribution of rare earth elements and uranium in various components of ordinary chondrites

    NASA Astrophysics Data System (ADS)

    Ebihara, M.; Honda, M.

    1984-06-01

    Rare earth elements (REE) and uranium were studied for their distributions in various component phases of four ordinary chondrites. Kesen (H4), Richardton (H5), Bruderheim (L6), and Saint Severin (LL6). A selective dissolution method was applied for the phase fractionation. The REE were analysed by neutron activation analysis, and U was determined by neutron-induced fission tracks. The present study revealed that both REE and U are highly enriched in the Ca-phosphate minerals with different enrichment factors, implying chemical fractionation between them. The phosphates seem to be responsible for more than 80 percent of the light REE in all chondrites. On the other hand, only 20-40 percent of the total U resides in the Ca-phosphates. This difference in enrichments might have been caused through the levels of metamorphic activity on the meteoritic parent bodies.

  17. Predictive model for ionic liquid extraction solvents for rare earth elements

    SciTech Connect

    Grabda, Mariusz; Oleszek, Sylwia; Panigrahi, Mrutyunjay; Kozak, Dmytro; Shibata, Etsuro; Nakamura, Takashi; Eckert, Franck

    2015-12-31

    The purpose of our study was to select the most effective ionic liquid extraction solvents for dysprosium (III) fluoride using a theoretical approach. Conductor-like Screening Model for Real Solvents (COSMO-RS), based on quantum chemistry and the statistical thermodynamics of predefined DyF{sub 3}-ionic liquid systems, was applied to reach the target. Chemical potentials of the salt were predicted in 4,400 different ionic liquids. On the base of these predictions set of ionic liquids’ ions, manifesting significant decrease of the chemical potentials, were selected. Considering the calculated physicochemical properties (hydrophobicity, viscosity) of the ionic liquids containing these specific ions, the most effective extraction solvents for liquid-liquid extraction of DyF{sub 3} were proposed. The obtained results indicate that the COSMO-RS approach can be applied to quickly screen the affinity of any rare earth element for a large number of ionic liquid systems, before extensive experimental tests.

  18. Anthropogenic rare earth element fluxes into floodplains: Coupling between geochemical monitoring and hydrodynamic sediment transport modelling

    NASA Astrophysics Data System (ADS)

    Hissler, Christophe; Hostache, Renaud; Iffly, Jean François; Pfister, Laurent; Stille, Peter

    2015-09-01

    As all rare earth elements (REEs) have an increasingly important role in high tech industries, they are now recognized as emergent pollutants in river systems impacted by anthropogenic activity. Over the past 20 years, significant anthropogenic contributions were reported for Gd, La and Sm, and we may expect that REE contamination in rivers is to further increase in a near future. Despite the work done to assess the environmental impact of REE pollutions in larger river systems, we are still lacking information on the dynamics of these anthropogenic compounds in relation to hydrological changes. Here, we observed for the first time particulate Ce originating from local industrial activities in Luxembourg and we quantified the anthropogenic contribution to the REE fluxes at the river basin scale during a single flood event.

  19. The distribution of Sr and REE between diopside and silicate liquid. [Rare Earth Elements

    NASA Technical Reports Server (NTRS)

    Grutzeck, M.; Kridelbaugh, S.; Weill, D.

    1974-01-01

    Experimental determination of the distribution coefficients in diopside-liquid pairs for strontium and nine rare-earth elements in the system CaMgSi2O6-NaAlSi3O8-CaAl2Si2O8. In experiments in air at 1265 C it is found that most of the Sr(2+), Eu(2+), and RE(3+) ions substitute for Ca(2+) and, in addition, a coupled substitution of Al(3+) for Si(4+) occurs. All of the trace ions considered are found to be excluded from the diopside lattice relative to the liquid. In the case of the trivalent ions the exclusion is much more pronounced for La and Ce, which have ionic radii larger than that of Ca(2+) in 8-fold oxygen coordination. Divalent Sr and Eu with even larger radii are also strongly excluded.

  20. Predictive model for ionic liquid extraction solvents for rare earth elements

    NASA Astrophysics Data System (ADS)

    Grabda, Mariusz; Oleszek, Sylwia; Panigrahi, Mrutyunjay; Kozak, Dmytro; Eckert, Franck; Shibata, Etsuro; Nakamura, Takashi

    2015-12-01

    The purpose of our study was to select the most effective ionic liquid extraction solvents for dysprosium (III) fluoride using a theoretical approach. Conductor-like Screening Model for Real Solvents (COSMO-RS), based on quantum chemistry and the statistical thermodynamics of predefined DyF3-ionic liquid systems, was applied to reach the target. Chemical potentials of the salt were predicted in 4,400 different ionic liquids. On the base of these predictions set of ionic liquids' ions, manifesting significant decrease of the chemical potentials, were selected. Considering the calculated physicochemical properties (hydrophobicity, viscosity) of the ionic liquids containing these specific ions, the most effective extraction solvents for liquid-liquid extraction of DyF3 were proposed. The obtained results indicate that the COSMO-RS approach can be applied to quickly screen the affinity of any rare earth element for a large number of ionic liquid systems, before extensive experimental tests.

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

    PubMed

    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

  2. Rare earth and trace element geochemistry of a fragment of Jurassic seafloor, Point Sal, California

    NASA Technical Reports Server (NTRS)

    Menzies, M.; Blanchard, D.; Brannon, J.; Korotev, R.

    1977-01-01

    Rocks from an ophiolite suite once on the seafloor were analyzed for rare earth elements (REE), Sc, Co, Na2O, Cr, Zn and FeO. Strontium isotope exchange noted in some of the lavas is attributed to basalt-seawater interaction; the Ce abundance in smectite- and zeolite-bearing lavas may also be due to prolonged exposure to seawater. The higher grades of metamorphic rock, however, show no variation from the usual flat or slightly light REE depleted profiles. Plutonic igneous rock, all light REE depleted, have total REE abundances varying by a factor of 100 between the dunites and diorites. In order of decreasing REE abundance are hornblende, clinopyroxene, plagioclase, orthopyroxene and olivine. Calculations of REE contents of liquids in equilibrium with early cumulative clinopyroxenes suggest that the parent to the stratiform sequence was more depleted in light REE than the parent to the lava pile.

  3. Study on the electrochemical extraction of rare earth elements from FLINAK

    SciTech Connect

    Long, Dewu; Huang, Wei; Jiang, Feng; Tian, Lifang; Li, Qingnuan

    2013-07-01

    Electrochemical behaviors of rare earth elements, such as NdF{sub 3}, GdF{sub 3}, SmF{sub 3}, YF{sub 3}, and EuF{sub 3}, were investigated in a LiF-NaF-KF (46.5-11.5-42.0 mol %, FLINAK, m. p. 454 Celsius degrees) solvent. The results indicated that it is possible to extract Nd, Gd and Y directly by electrochemical deposition since the reductions of those cations to metal are located in the electrochemical window of the FLINAK eutectic, while the reductions of Sm and Eu metal are out of the range of the medium. Subsequently electro-deposition of Nd was carried out with two kinds of cathodic materials, namely, an inert cathode, Pt, and a reactive electrode, Cu. The collected products were characterized by various techniques revealing that a Nd-rich product was obtained. (authors)

  4. Behavior of Rare Earth Element In Geothermal Systems; A New Exploration/Exploitation Tool

    SciTech Connect

    Scott A. Wood

    2002-01-28

    The goal of this four-year project was to provide a database by which to judge the utility of the rare earth elements (REE) in the exploration for and exploitation of geothermal fields in the United States. Geothermal fluids from hot springs and wells have been sampled from a number of locations, including: (1) the North Island of New Zealand (1 set of samples); (2) the Cascades of Oregon; (3) the Harney, Alvord Desert and Owyhee geothermal areas of Oregon; (4) the Dixie Valley and Beowawe fields in Nevada; (5) Palinpion, the Philippines: (6) the Salton Sea and Heber geothermal fields of southern California; and (7) the Dieng field in Central Java, Indonesia. We have analyzed the samples from all fields for REE except the last two.

  5. Binary rare earth element-Ni/Co metallic glasses with distinct β-relaxation behaviors

    SciTech Connect

    Zhu, Z. G.; Wang, Z.; Wang, W. H.

    2015-10-21

    We report the formation of a series of rare earth element (RE)-Ni/Co binary metallic glasses (MGs) with unusual distinct β-relaxation peak compared with that of most of the reported MGs which usually exhibit as an excess wing or a shoulder. The β-relaxation behavior of RE-Ni/Co MGs is sensitive to the composition and the atomic radii of the RE and can be tuned through changing the fraction of RE-Ni (or Co) atomic pairs. The novel RE-Ni/Co MGs with distinct β-relaxation can serve as model system to investigate the nature of the β-relaxation as well as its relations with other physical and mechanical properties of MGs.

  6. Geochemistry of rare earth elements in a passive treatment system built for acid mine drainage remediation.

    PubMed

    Prudêncio, Maria Isabel; Valente, Teresa; Marques, Rosa; Sequeira Braga, Maria Amália; Pamplona, Jorge

    2015-11-01

    Rare earth elements (REE) were used to assess attenuation processes in a passive system for acid mine drainage treatment (Jales, Portugal). Hydrochemical parameters and REE contents in water, soils and sediments were obtained along the treatment system, after summer and winter. A decrease of REE contents in the water resulting from the interaction with limestone after summer occurs; in the wetlands REE are significantly released by the soil particles to the water. After winter, a higher water dynamics favors the AMD treatment effectiveness and performance since REE contents decrease along the system; La and Ce are preferentially sequestered by ochre sludge but released to the water in the wetlands, influencing the REE pattern of the creek water. Thus, REE fractionation occurs in the passive treatment systems and can be used as tracer to follow up and understand the geochemical processes that promote the remediation of AMD. PMID:26247412

  7. Site-selective Mott transition in rare-earth-element nickelates.

    PubMed

    Park, Hyowon; Millis, Andrew J; Marianetti, Chris A

    2012-10-12

    A combination of density functional and dynamical mean field theory calculations are used to show that the remarkable metal-insulator transition in the rare-earth-element nickelate perovskites arises from a site-selective Mott phase, in which the d electrons on half of the Ni ions are localized to form a fluctuating moment while the d electrons on other Ni ions form a singlet with holes on the surrounding oxygen ions. The calculation reproduces key features observed in the nickelate materials, including an insulating gap in the paramagnetic state, a strong variation of static magnetic moments among Ni sites and an absence of charge order. A connection between structure and insulating behavior is documented. The site-selective Mott transition may be a more broadly applicable concept in the description of correlated materials. PMID:23102343

  8. X-ray fluorescence analysis of rare earth elements in rocks using low dilution glass beads.

    PubMed

    Nakayama, Kenichi; Nakamura, Toshihiro

    2005-07-01

    Major and trace elements (Na, Mg, Al, Si, P, K, Ca, Ti, Mn, Fe, Rb, Sr, Y, Zr, La, Ce, Pr, Nd, Sm, Gd, Dy, Th and U) in igneous rocks were assayed with fused lithium borate glass beads using X-ray fluorescence spectrometry. Low dilution glass beads, which had a 1:1 sample-to-flux ratio, were prepared for determination of rare earth elements. Complete vitrification of 1:1 mixture required heating twice at 1200 degrees C with agitation. Extra pure reagents containing determinants were used for calibrating standards instead of the rock standard. The calibration curves of the 23 elements showed good linearity. Furthermore, the lower limits of detection corresponding to three times the standard deviation for blank measurements were 26 mass ppm for Na2O, 6.7 for MgO, 4.5 for Al2O3, 4.5 for SiO2, 18 for P2O5, 1.1 for K2O, 4.0 for CaO, 3.9 for TiO2, 1.6 for MnO, 0.8 for Fe2O3, 0.5 for Rb, 0.2 for Sr, 0.4 for Y, 0.5 for Zr, 3.3 for La, 6.5 for Ce, 2.7 for Pr, 2.1 for Nd, 1.7 for Sm, 0.7 for Gd, 2.7 for Dy, 0.5 for Th, and 0.6 for U. Using the present method, we determined the contents of these 23 elements in four rhyolitic and granitic rocks from Japan. PMID:16038502

  9. Galileo Earth approach navigation using connected-element interferometer phase-delay tracking

    NASA Technical Reports Server (NTRS)

    Thurman, S. W.

    1990-01-01

    The application of a Connected-Element Interferometer (CEI) to the navigation of the Galileo spacecraft during its encounter with Earth in December 1990 is investigated. A CEI tracking demonstration is planned for the week of November 11 through 18, 1990, from 27 days to 20 days prior to Earth encounter on December 8. During this period, the spacecraft will be tracked daily with Deep Space Network Stations 13 and 15 at Goldstone. The purpose of this work is twofold: first, to establish and define the navigation performance expected during the tracking demonstration and, second, to study, in a more general sense, the sensitivity of orbit demonstration results obtained with CEI to the data density within CEI tracking passes and to important system parameters, such as baseline orientation errors and the phase-delay measurement accuracy. Computer simulation results indicate that the use of CEI data, coupled with conventional range and Doppler data, may reduce the uncertainty in the declination of the spacecraft's incoming trajectory by 15 to 66 percent compared with the operational solution using range and Doppler data only. The level of improvement depends upon the quantity and quality of the CEI data.

  10. Bioadsorption of rare earth elements through cell surface display of lanthanide binding tags

    DOE PAGESBeta

    Park, Dan M.; Reed, David W.; Yung, Mimi C.; Eslamimanesh, Ali; Lencka, Malgorzata M.; Anderko, Andrzej; Fujita, Yoshiko; Riman, Richard E.; Navrotsky, Alexandra; Jiao, Yongqin

    2016-02-02

    In this study, with the increasing demand for rare earth elements (REEs) in many emerging clean energy technologies, there is an urgent need for the development of new approaches for efficient REE extraction and recovery. As a step toward this goal, we genetically engineered the aerobic bacterium Caulobacter crescentus for REE adsorption through high-density cell surface display of lanthanide binding tags (LBTs) on its S-layer. The LBT-displayed strains exhibited enhanced adsorption of REEs compared to cells lacking LBT, high specificity for REEs, and an adsorption preference for REEs with small atomic radii. Adsorbed Tb3+ could be effectively recovered using citrate,more » consistent with thermodynamic speciation calculations that predicted strong complexation of Tb3+ by citrate. No reduction in Tb3+ adsorption capacity was observed following citrate elution, enabling consecutive adsorption/desorption cycles. The LBT-displayed strain was effective for extracting REEs from the acid leachate of core samples collected at a prospective rare earth mine. Our collective results demonstrate a rapid, efficient, and reversible process for REE adsorption with potential industrial application for REE enrichment and separation.« less

  11. Bioadsorption of Rare Earth Elements through Cell Surface Display of Lanthanide Binding Tags.

    PubMed

    Park, Dan M; Reed, David W; Yung, Mimi C; Eslamimanesh, Ali; Lencka, Malgorzata M; Anderko, Andrzej; Fujita, Yoshiko; Riman, Richard E; Navrotsky, Alexandra; Jiao, Yongqin

    2016-03-01

    With the increasing demand for rare earth elements (REEs) in many emerging clean energy technologies, there is an urgent need for the development of new approaches for efficient REE extraction and recovery. As a step toward this goal, we genetically engineered the aerobic bacterium Caulobacter crescentus for REE adsorption through high-density cell surface display of lanthanide binding tags (LBTs) on its S-layer. The LBT-displayed strains exhibited enhanced adsorption of REEs compared to cells lacking LBT, high specificity for REEs, and an adsorption preference for REEs with small atomic radii. Adsorbed Tb(3+) could be effectively recovered using citrate, consistent with thermodynamic speciation calculations that predicted strong complexation of Tb(3+) by citrate. No reduction in Tb(3+) adsorption capacity was observed following citrate elution, enabling consecutive adsorption/desorption cycles. The LBT-displayed strain was effective for extracting REEs from the acid leachate of core samples collected at a prospective rare earth mine. Our collective results demonstrate a rapid, efficient, and reversible process for REE adsorption with potential industrial application for REE enrichment and separation. PMID:26836847

  12. Planktonic foraminiferal rare earth elements as a potential new aeolian dust proxy

    NASA Astrophysics Data System (ADS)

    Chou, C.; Liu, Y.; Lo, L.; Wei, K.; Shen, C.

    2012-12-01

    Characteristics of rare earth elements (REEs) have widely been used as important tracers in many fields of earth sciences, including lithosphere research, environmental change, ocean circulation and other natural carbonate materials. Foraminiferal test REE signatures have been suggested to reflect ambient seawater conditions and serve as valuable proxies in the fields of paleoceanography and paleoclimate. Here we present a 60-kyr planktonic foraminifera Globigerinoides ruber (white, 250-300 μm) REE record of a sediment core MD05-2925 (9°20.61'S, 151°27.61'E, water depth 1660 m) from the Solomon Sea. The REE diagram shows two dominant sources of local seawater and nearby terrestrial input. The variability of foraminiferal REE/Ca time series is different from Mg/Ca-inferred sea surface temperature and δ18O records during the past 60-kyr. This inconsistency suggests that planktonic foraminiferal REE content cannot result only from changes in ice volume and temperature. Synchroneity between high planktonic foraminiferal REE content and Antarctic ice core dust amount record implies the same dust sources, probably from Australia or mainland China. Our results suggest that foraminiferal REE can potentially be as a new dust proxy and record dry/humid conditions at the source area.

  13. Geology and market-dependent significance of rare earth element resources

    NASA Astrophysics Data System (ADS)

    Simandl, G. J.

    2014-09-01

    China started to produce rare earth elements (REEs) in the 1980s, and since the mid-1990s, it has become the dominant producer. Rare earth element export quotas first introduced by the Chinese government in the early 2000s were severely reduced in 2010 and 2011. This led to strong government-created disparity between prices within China and the rest of the world. Industrialized countries identified several REEs as strategic metals. Because of rapid price increases of REE outside of China, we have witnessed a world-scale REE exploration rush. The REE resources are concentrated in carbonatite-related deposits, peralkaline igneous rocks, pegmatites, monazite ± apatite veins, ion adsorption clays, placers, and some deep ocean sediments. REE could also be derived as a by-product of phosphate fertilizer production, U processing, mining of Ti-Zr-bearing placers, and exploitation of Olympic Dam subtype iron oxide copper gold (IOCG) deposits. Currently, REEs are produced mostly from carbonatite-related deposits, but ion adsorption clay deposits are an important source of heavy REE (HREE). Small quantities of REE are derived from placer deposits and one peralkaline intrusion-related deposit. The ideal REE development targets would be located in a politically stable jurisdiction with a pro-mining disposition such as Canada and Australia. REE grade, HREE/light REE (LREE) ratio of the mineralization, tonnage, mineralogy, and permissive metallurgy are some of the key technical factors that could be used to screen potential development projects. As REEs are considered strategic metals from economic, national security, and environmental points of view, technical and economic parameters alone are unlikely to be used in REE project development decision-making. Recycling of REE is in its infancy and unless legislated, in the short term, it is not expected to contribute significantly to the supply of REE.

  14. Natural radioactivity and rare earth elements in feldspar samples, Central Eastern desert, Egypt.

    PubMed

    Walley El-Dine, Nadia; El-Shershaby, Amal; Afifi, Sofia; Sroor, Amany; Samir, Eman

    2011-05-01

    The pegmatite bodies of the Eastern Desert of Egypt are widely distributed especially along the Marsa-Alam-Idfu road. The Abu Dob area covers about 150km(2) of the Arabian Nubian shield at the central part of the Eastern Desert of Egypt. Most of the pegmatite is zoned; the zonation starts with milky quartz at the core followed by alkali feldspar at the margins. The feldspars vary in color from rose to milky and in composition from K-feldspar to Na-feldspar, sometimes interactions of both types are encountered. Thirteen feldspar samples were collected from different locations in the Abu Dob area for measuring the natural radioactivity of (238)U, (232)Th and (40)K using an HPGe detector. The variation in concentration of radionuclides for the area under investigation can be classified into regions of high, medium and low natural radioactivity. The average concentration in BqKg(-1) has been observed to be from 9.5 to 183675.7BqKg(-1) for (238)U, between 6.1 and 94,314.2BqKg(-1) for (232)Th and from 0 to 7894.6BqKg(-1) for (40)K. Radium equivalent activities (Ra(eq)), dose rate (D(R)) and external hazard (H(ex)) have also been determined. In the present work, the concentration of rare earth elements are measured for two feldspar samples using two techniques, Environmental Scanning Electron microscope XIL 30 ESEM, Philips, and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The existence of rare earth elements in this area are very high and can be used in different important industries. PMID:21324705

  15. A major light rare-earth element (LREE) resource in the Khanneshin carbonatite complex, southern Afghanistan

    USGS Publications Warehouse

    Tucker, Robert D.; Belkin, Harvey E.; Schulz, Klaus J.; Peters, Stephen G.; Horton, Forrest; Buttleman, Kim; Scott, Emily R.

    2012-01-01

    The rapid rise in world demand for the rare-earth elements (REEs) has expanded the search for new REE resources. We document two types of light rare-earth element (LREE)-enriched rocks in the Khanneshin carbonatite complex of southern Afghanistan: type 1 concordant seams of khanneshite-(Ce), synchysite-(Ce), and parisite-(Ce) within banded barite-strontianite alvikite, and type 2 igneous dikes of coarse-grained carbonatite, enriched in fluorine or phosphorus, containing idiomorphic crystals of khanneshite-(Ce) or carbocernaite. Type 1 mineralized barite-strontianite alvikite averages 22.25 wt % BaO, 4.27 wt % SrO, and 3.25 wt % ∑ LREE2O3 (sum of La, Ce, Pr, and Nd oxides). Type 2 igneous dikes average 14.51 wt % BaO, 5.96 wt % SrO, and 3.77 wt % ∑ LREE2O3. A magmatic origin is clearly indicated for the type 2 LREE-enriched dikes, and type 1 LREE mineralization probably formed in the presence of LREE-rich hydrothermal fluid. Both types of LREE mineralization may be penecontemporaneous, having formed in a carbonate-rich magma in the marginal zone of the central vent, highly charged with volatile constituents (i.e., CO2, F, P2O5), and strongly enriched in Ba, Sr, and the LREE. Based on several assumptions, and employing simple geometry for the zone of LREE enrichment, we estimate that at least 1.29 Mt (million metric tonnes) of LREE2O3 is present in this part of the Khanneshin carbonatite complex.

  16. Rare earth element components in atmospheric particulates in the Bayan Obo mine region

    SciTech Connect

    Wang, Lingqing Liang, Tao Zhang, Qian; Li, Kexin

    2014-05-01

    The Bayan Obo mine, located in Inner Mongolia, China, is the largest light rare earth body ever found in the world. The research for rare earth elements (REEs) enrichment in atmospheric particulates caused by mining and ore processing is fairly limited so far. In this paper, atmospheric particulates including total suspended particulate (TSP) matter and particles with an equivalent aerodynamic diameter less than 10 μm (PM{sub 10}) were collected around the Bayan Obo mine region, in August 2012 and March 2013, to analyze the levels and distributions of REEs in particles. The total concentrations of REEs for TSP were 149.8 and 239.6 ng/m{sup 3}, and those for PM{sub 10} were 42.8 and 68.9 ng/m{sup 3}, in August 2012 and March 2013, respectively. Enrichment factor was calculated for all 14 REEs in the TSP and PM{sub 10} and the results indicated that REEs enrichment in atmosphere particulates was caused by anthropogenic sources and influenced by the strong wind in springtime. The spatial distribution of REEs in TSP showed a strong gradient concentration in the prevailing wind direction. REE chondrite normalized patterns of TSP and PM{sub 10} were similar and the normalized curves inclined to the right side, showing the conspicuous fractionation between the light REEs and heavy REE, which supported by the chondrite normalized concentration ratios calculated for selected elements (La{sub N}/Yb{sub N}, La{sub N}/Sm{sub N}, Gd{sub N}/Yb{sub N}). - Highlights: • TSP and PM{sub 10} samples were collected to analyze the levels and distributions of REE. • Enrichment factors indicated that REE enrichment was caused by anthropogenic sources. • The distribution of REEs showed a strong gradient in the prevailing wind direction. • Obvious fractionation between LREEs and HREEs is observed in atmospheric particulates.

  17. Geology and market-dependent significance of rare earth element resources

    NASA Astrophysics Data System (ADS)

    Simandl, G. J.

    2014-12-01

    China started to produce rare earth elements (REEs) in the 1980s, and since the mid-1990s, it has become the dominant producer. Rare earth element export quotas first introduced by the Chinese government in the early 2000s were severely reduced in 2010 and 2011. This led to strong government-created disparity between prices within China and the rest of the world. Industrialized countries identified several REEs as strategic metals. Because of rapid price increases of REE outside of China, we have witnessed a world-scale REE exploration rush. The REE resources are concentrated in carbonatite-related deposits, peralkaline igneous rocks, pegmatites, monazite ± apatite veins, ion adsorption clays, placers, and some deep ocean sediments. REE could also be derived as a by-product of phosphate fertilizer production, U processing, mining of Ti-Zr-bearing placers, and exploitation of Olympic Dam subtype iron oxide copper gold (IOCG) deposits. Currently, REEs are produced mostly from carbonatite-related deposits, but ion adsorption clay deposits are an important source of heavy REE (HREE). Small quantities of REE are derived from placer deposits and one peralkaline intrusion-related deposit. The ideal REE development targets would be located in a politically stable jurisdiction with a pro-mining disposition such as Canada and Australia. REE grade, HREE/light REE (LREE) ratio of the mineralization, tonnage, mineralogy, and permissive metallurgy are some of the key technical factors that could be used to screen potential development projects. As REEs are considered strategic metals from economic, national security, and environmental points of view, technical and economic parameters alone are unlikely to be used in REE project development decision-making. Recycling of REE is in its infancy and unless legislated, in the short term, it is not expected to contribute significantly to the supply of REE.

  18. Performance evaluation of Laser Induced Breakdown Spectroscopy (LIBS) for quantitative analysis of rare earth elements in phosphate glasses

    NASA Astrophysics Data System (ADS)

    Devangad, Praveen; Unnikrishnan, V. K.; Nayak, Rajesh; Tamboli, M. M.; Muhammed Shameem, K. M.; Santhosh, C.; Kumar, G. A.; Sardar, D. K.

    2016-02-01

    In the current study, we have determined the elemental compositions of synthesized rare earth doped phosphate glasses using a laboratory Laser-Induced Breakdown Spectroscopy (LIBS) system. LIBS spectra of this rare earth (samarium (Sm), thulium (Tm) and ytterbium (Yb)) doped glass samples with known composition are recorded using a highly sensitive detector. Major atomic emission lines of Sm, Tm and Yb found in LIBS spectra are reported. By considering the atomic emission line of phosphorous as an internal standard, calibration curves were constructed for all the rare earth concentrations. Very good linear regression coefficient (R2) values were obtained using this technique. Analytical predictive skill of LIBS was studied further using leave-one-out method. Low values of the reported correlation uncertainty between measured LIBS concentration ratio and certified concentration ratio confirms that LIBS technique has great potential for quantitative analysis of rare earth elements in glass matrix.

  19. Structural Elements in a Persistent Identifier Infrastructure and Resulting Benefits for the Earth Science Community

    NASA Astrophysics Data System (ADS)

    Weigel, T.; Toussaiant, F.; Stockhause, M.; Höck, H.; Kindermann, S.; Lautenschlager, M.; Ludwig, T.

    2012-12-01

    We propose a wide adoption of structural elements (typed links, collections, trees) in the Handle System to improve identification and access of scientific data, metadata and software as well as traceability of data provenance. Typed links target the issue of data provenance as a means to assess the quality of scientific data. Data provenance is seen here as a directed acyclic graph with nodes representing data and vertices representing derivative operations (Moreau 2010). Landing pages can allow a human user to explore the provenance graph back to the primary unprocessed data, thereby also giving credit to the original data producer. As in Earth System Modeling no single infrastructure with complete data lifecycle coverage exists, we propose to split the problem domain in two parts. Project-specific infrastructures such as the German project C3-Grid or the Earth System Grid Federation (ESGF) for CMIP5 data are aware of data and data operations (Toussaint et al. 2012) and can thus detect and accumulate single nodes and vertices in the provenance graph, assigning Handles to data, metadata and software. With a common schema for typed links, the provenance graph is established as downstream infrastructures refer incoming Handles. Data in this context is for example hierarchically structured Earth System model output data, which receives DataCite DOIs only for the most coarse-granular elements. Using Handle tree structures, the lower levels of the hierarchy can also receive Handles, allowing authors to more precisely identify the data they used (Lawrence et al. 2011). We can e.g. define a DOI for just the 2m-temperature variable of CMIP5 data across many CMIP5 experiments or a DOI for model and observational data coming from different sources. The structural elements should be implemented through Handle values at the Handle infrastructure level for two reasons. Handle values are more durable than downstream websites or databases, and thus the provenance chain does not

  20. Dissolved Rare Earth Element Concentrations in the Upwelling area off Peru

    NASA Astrophysics Data System (ADS)

    Grasse, P.; Plass, A.; Hathorne, E. C.; Frank, M.

    2012-12-01

    Rare earth elements (REEs) are powerful tracers of continental input, particle exchange and scavenging processes, as well as for water mass transport in the ocean. We present a first data set of dissolved REE distributions in filtered seawater covering the major gradients of bio-productivity and oxygen concentrations in the upwelling area off Peru. A total of 22 stations were analyzed along a shelf, a nearshore and an offshore transect to investigate the influence of local inputs versus water mass mixing. The Peruvian coastal upwelling area is a highly dynamic system characterized by intense upwelling of nutrient-rich subsurface water and therefore high productivity that leads to one of the globally largest Oxygen Minimum Zones (OMZ). The upwelling area off Peru is of particular interest for understanding the biogeochemical cycling of REEs and other redox-sensitive metals because anoxic conditions are expected to release of REEs from the shelf, whereas high particle densities and fluxes efficiently remove the REEs from the water column. Despite their high potential as tracers few systematic investigations of seawater REEs have been carried out so far because the low concentrations of REEs (pM) are difficult to measure. In this study an online preconcentration (OP) system (seaFast, Elemental Scientific Inc.) was used with a technique slightly modified from Hathorne et al. (2012). The OP system efficiently separates seawater matrix elements from the REEs and elutes the preconcentrated sample directly into the spray chamber of the ICP-MS instrument. Repeated measurements of a seawater reference sample (n= 20) during this study gave a reproducibility of between 5% and 15% (2σ), with the worst reproducibility for Sm, Eu, and Gd (12% to 15%). In general, the REEs, except Ce, show a nutrient-like behavior in seawater increasing in concentration with water depth. However, such distributions were not observed for some stations on the shelf where the highest concentrations

  1. Seawater-derived rare earth element addition to abyssal peridotites during serpentinization

    NASA Astrophysics Data System (ADS)

    Frisby, Carl; Bizimis, Michael; Mallick, Soumen

    2016-04-01

    Serpentinized abyssal peridotites are evidence for active communication between the Earth's hydrosphere and the upper mantle, where exchange and retention of both major and trace elements occur. Bulk rock Nd isotopes in serpentinized abyssal peridotites imply interaction of seawater with the peridotite. In contrast, the Nd isotopes of clinopyroxenes from serpentinized abyssal peridotites retain their primary magmatic signature. It is currently unclear if, how and where seawater-derived Nd and other REE are being added or exchanged with the mantle peridotite minerals during serpentinization. To remedy this knowledge gap, we present in situ trace and major element concentrations, bulk rock and sequential leaching experiment trace element concentrations as well as Nd, Sr isotope data on refertilized and depleted serpentinized abyssal peridotites from the Southwest Indian Ridge. The secondary serpentine matrix and magnetite veins in these peridotites have elevated LREE concentrations, with variable negative Ce anomalies and large Rb, Sr, Pb and U enrichments that resemble seawater trace element patterns. The LREE concentrations in the serpentine phase are higher than those expected for the primary mantle mineralogy (olivine, orthopyroxene) based on data from relic clinopyroxenes and equilibrium partition coefficients. These data are consistent with seawater-derived REE addition to the peridotite during serpentinization. The bulk rocks have more radiogenic Sr and more unradiogenic Nd isotopes than their clinopyroxene (up to 8 εNd units lower than clinopyroxene). Sequential leaching experiments designed to mobilize secondary carbonates and Fe-oxides show even more unradiogenic Nd isotope ratios in the leachates than the bulk rock and clinopyroxene, approaching seawater compositions (up to 15 εNd units lower than clinopyroxene). Mass balance calculations using trace elements or Nd isotopes suggest that up to 30% of the bulk peridotite Nd budget is of seawater origin and

  2. Key Factors Controlling Space- and Time-Linked Rare Earth Element Distribution in Shallow Groundwaters

    NASA Astrophysics Data System (ADS)

    Dia, A.; Gruau, G.; Olivie-Lauquet, G.; Henin, O.; Petitjean, P.; Le Coz-Bouhnik, M.

    2001-12-01

    This study investigates the effects of source-rock composition, redox changes and organic matter on the hydrochemistry of Rare Earth Elements (REE). Wetland groundwater samples as well as upland zone water samples were recovered weekly over a six month period (January to June 1999) from a small catchment (Petit Hermitage, France). The samples were filtered on the field using membrane filters of 0.22 μ m pore size, and then analyzed for their Dissolved Organic Carbon (DOC) as well as Fe, Mn, Al, Th, U and REE concentrations. The results are discussed in conjunction with previous published DOC and trace-element concentrations obtained on comparable samples from three other small catchments, namely : the Nsimi-Zoetele, Goyoum (both in Cameroon) and Kervidy/Coet-Dan (France) catchments (Viers et al., 1997; Braun et al., 1998; Dia et al., 2000). Despite marked differences (such as bioclimatic conditions, vegetation cover, basement rock composition or human activity), results are surprisingly similar with always the occurrence of two spatially distinct groundwater types including : (i) a shallow, organic-rich groundwater below wetlands recording high and variable REE contents and displaying slight or no negative Ce anomaly. In the wetland groundwaters, the REE and other trace-element concentrations seem to be controlled by seasonal dynamics, involving both temperature, whose onset at spring leads to higher organic carbon decomposition rates by microbial mass, and redox changes resulting in REE and other-trace element release in water when mineral phases occur to dissolve. (ii) The second groundwater type corresponds to a shallow, organic-poor groundwater type located below the hillslope domains. This second groundwater type displays lower REE (and other trace-element) concentrations, but distinguish from the former by the occurrence of very strong negative Ce anomalies, whose amplitude is variable, but appears to be linked to the sampling location along the catena. The

  3. Substitution of Nd with other rare earth elements in melt spun Nd2Fe14B magnets

    NASA Astrophysics Data System (ADS)

    Brown, D. N.; Lau, D.; Chen, Z.

    2016-05-01

    This is a contemporary study of rapidly quenched Nd1.6X0.4Fe14B magnetic materials (where X= Nd, Y, Ce, La, Pr, Gd and Ho). A 20% substitution of the Nd component from Nd2Fe14B can bring about some commercial advantage. However, there will be some compromise to the magnetic performance. Light rare earth elements are definitely more abundant (Y, Ce, La) than the heavier rare earth elements, but when they are included in RE2Fe14B magnets they tend to lower magnetic performance and thermal stability. Substituting heavy rare earth elements (Gd, Ho) for Nd in Nd2Fe14B improves the thermal stability of magnets but causes a loss in magnet remanence.

  4. Developing alternative resources of rare earth elements in Europe - EURARE and the red mud challenge

    NASA Astrophysics Data System (ADS)

    Deady, Eimear; Mouchos, Evangelos; Goodenough, Kathryn; Wall, Frances; Williamson, Ben

    2015-04-01

    Rare earth elements (REE) are considered to be highly "critical" by the European Commission [1], owing to the concentration of global supply [2] and their use in a wide range of emerging technologies (e.g. smart phones, electric cars and wind turbines). The main source of REE is the mineral bastnäsite, which is primarily extracted from carbonatites. Alternative resources of REE have been identified in a variety of other environments such as alluvial placers, bauxites and ore tailings. The EURARE project (www.eurare.eu), funded by the European Commission, aims to improve understanding of potential REE resources in Europe with the overall objective of establishing the basis for a European REE industry. As a part of this project, alternative sources of rare earth elements in Europe are being considered. REE have been identified as being particularly enriched in karst-bauxites and hence in the red muds generated as a waste product from the processing of these bauxites to alumina through the Bayer process [3]. Karst-bauxites are widely distributed with deposits known across the Mediterranean and with intermittent exploitation occurring over many decades. REE become concentrated in the bauxite deposits by the bauxitisation process and are retained due to the geochemical barrier created by the limestone bedrock below. This can result in several processes, including the crystallisation of authigenic REE-bearing minerals, the accumulation of residual phases and the adsorption of ions onto clays and other mineral surfaces [4]. Red muds produced from alumina processing represent a potentially important concentration of REE as it has been demonstrated that the REE pass through the alumina extraction process into the waste, and the total REE concentrations are typically enriched by a factor of two compared with the original bauxite ore [5]. Bauxites and red muds from the Parnassus Ghiona region of Greece [6] and the Seydişehir-Akseki region of Turkey have been assessed as

  5. Geochemistry of the rare earth elements in ferromanganese nodules from DOMES Site A, northern equatorial Pacific

    USGS Publications Warehouse

    Calvert, S.E.; Piper, D.Z.; Baedecker, P.A.

    1987-01-01

    The distribution of rare earth elements (REE) in ferromanganese nodules from DOMES Site A has been determined by instrumental neutron activation methods. The concentrations of the REE vary markedly. Low concentrations characterize samples from a depression (the valley), in which Quaternary sediments are thin or absent; high concentrations are found in samples from the surrounding abyssal hills (the highlands) where the Quaternary sediment section is relatively thick. Moreover, the valley nodules are strongly depleted in the light trivalent REE (LREE) and Ce compared with nodules from the highlands, some of the former showing negative Ce anomalies. The REE abundances in the nodules are strongly influenced by the REE abundances in coexisting bottom water. Some controls on the REE chemistry of bottom waters include: a) the more effective removal of the LREE relative to the HREE from seawater because of the greater degree of complexation of the latter elements with seawater ligands, b) the very efficient oxidative scavenging of Ce on particle surfaces in seawater, and c) the strong depletion of both Ce and the LREE in, or a larger benthic flux of the HREE into, the Antarctic Bottom Water (AABW) which flows through the valley. The distinctive REE chemistry of valley nodules is a function of their growth from geochemically evolved AABW. In contrast, the REE chemistry of highland nodules indicates growth from a local, less evolved seawater source. ?? 1987.

  6. Distribution of rare earth elements in soil and grape berries of Vitis vinifera cv. "Glera".

    PubMed

    Pepi, Salvatore; Sansone, Luigi; Chicca, Milvia; Marrocchino, Elena; Vaccaro, Carmela

    2016-08-01

    The renowned Vitis vinifera L. cultivar "Glera" (Magnoliopsida Vitaceae) has been grown for hundreds of years in the Italian regions of Veneto and Friuli to produce the sparkling Prosecco wine, with controlled designation of origin (DOC). We evaluated the relationship among the concentrations of rare earth elements (REE) in soil and in "Glera" grape berries in vineyards belonging to five different localities in the Veneto alluvial plain, all included in the DOC area of Prosecco. The concentration of REE in samples of soil and juice or solid residues of grape berries was determined by inductively coupled plasma mass spectrometry (ICP-MS), and the index of bioaccumulation was calculated to define the specific assimilation of these elements from soil to grape berries. The concentration of REE in soil samples allowed an identification of each locality examined, and REE were mostly detected in solid grape berry residues in comparison to juice. These data may be useful to associate REE distribution in soil and grape berries to a specific geographical origin, in order to prevent fraudulent use of wine denomination labels. PMID:27447714

  7. Biosorption of Uranium and Rare Earth Elements Using Biomass of Algae

    PubMed Central

    Sakamoto, Nobuo; Kano, Naoki; Imaizumi, Hiroshi

    2008-01-01

    In order to investigate the behavior of rare earth elements (REEs) and uranium (U) in marine organism, the concentrations of REEs and U in some brown algae samples taken on the coast of Niigata Prefecture were determined. In addition, laboratory model experiment to uptake these elements using living and dried algae (Undaria pinnatifida and Sargassum hemiphyllum) was also carried out to survey the uptake and bioaccumulation mechanism of REEs and U in algae. Consequently, the following matters have been mainly clarified. (1) The order of the concentration of REEs for each organ in Sargassum hemiphyllum is “main branch” > “leaf” > “vesicle,” however for U, the order is “leaf” > “vesicle” > “main branch.” (2) The concentration of REEs in Sargassum hemiphyllum may be strongly affected by suspended solid in seawater. (3) The uptake and/or accumulate mechanism of REEs in brown algae may be different from that of U. PMID:19081786

  8. Uranium, thorium and rare earth elements in macrofungi: what are the genuine concentrations?

    PubMed

    Borovička, Jan; Kubrová, Jaroslava; Rohovec, Jan; Randa, Zdeněk; Dunn, Colin E

    2011-10-01

    Concentrations of uranium, thorium and rare earth elements (REE) in 36 species of ectomycorrhizal (26 samples) and saprobic (25 samples) macrofungi from unpolluted sites with differing bedrock geochemistry were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Analytical results are supported by use of certified reference materials (BCR-670, BCR-667, NIST-1575a) and the reliability of the determination of uranium was verified by epithermal neutron activation analysis (ENAA). It appears that data recently published on these elements are erroneous, in part because of use of an inappropriate analytical method; and in part because of apparent contamination by soil particles resulting in elevated levels of thorium and REE. Macrofungi from unpolluted areas, in general, did not accumulate high levels of the investigated metals. Concentrations of uranium and thorium were generally below 30 and 125 μg kg(-1) (dry weight), respectively. Concentrations of REE in macrofungi did not exceed 360 μg kg(-1) (dry weight) and their distribution more or less followed the trend observed in post-Archean shales and loess. PMID:21390524

  9. A New Fungal Isolate, Penidiella sp. Strain T9, Accumulates the Rare Earth Element Dysprosium

    PubMed Central

    Horiike, Takumi

    2015-01-01

    With an aim to develop a highly efficient method for the recovery of rare earth elements (REEs) by using microorganisms, we attempted to isolate dysprosium (Dy)-accumulating microorganisms that grow under acidic conditions from environmental samples containing high concentrations of heavy metals. One acidophilic strain, T9, which was isolated from an abandoned mine, decreased the concentration of Dy in medium that contained 100 mg/liter Dy to 53 mg/liter Dy after 3 days of cultivation at pH 2.5. The Dy content in the cell pellet of the T9 strain was 910 μg/mg of dry cells. The T9 strain also accumulated other REEs. Based on the results of 28S-D1/D2 rRNA gene sequencing and morphological characterization, we designated this fungal strain Penidiella sp. T9. Bioaccumulation of Dy was observed on the cell surface of the T9 strain by elemental mapping using scanning electron microscopy-energy dispersive X-ray spectroscopy. Our results indicate that Penidiella sp. T9 has the potential to recover REEs such as Dy from mine drainage and industrial liquid waste under acidic conditions. PMID:25710372

  10. Study of Kα2 /Kα1 RYIED in closed and open shell Rare Earth Elements

    NASA Astrophysics Data System (ADS)

    Chaves, P. C.; Tribolet, A. D.; Reis, M. A.

    2016-01-01

    Relative Yield Ion Energy Dependence (RYIED) was observed, named and reported as phenomenological evidence in 2005 (Reis et al., 2005). Since then, it was observed in transitions to the same subshell, and plausible explanations for the physics behind the phenomena have been proposed. In this work we present experimental evidence of the RYIED effect on the most inner transition possible in two Rare Earth Elements (REE), namely variations in the intensity ratio of Kα2 /Kα1 X-rays from Tm and Yb irradiated under different conditions. These REE are particularly interesting to start with since Yb has an electronic configuration where all the subshells are completely filled, whilst Tm misses one electron in the 4f subshell. Ultrapure oxides of each element were irradiated using proton beams having energies in the range of 0.9-3.6 MeV, in steps of 100 keV. Spectra were collected using the CdTe detector of the HRHE-PIXE set-up of C2TN and analysed using the DT2 code. Finally, the vanishing of the effect upon charging up of the target has been observed and will be discussed.

  11. Using rare earth elements for the identification of the geographic origin of food

    NASA Astrophysics Data System (ADS)

    Meisel, T.; Bandoniene, D.; Joebstl, D.

    2009-04-01

    The European Union defined regimes within the Protected Geographical Status (PGS) framework to protect names of regional food specialities. Thus only food produced in a specific geographical area with a specific way of production or quality can be protected by a protected geographical indication (PGI) label. As such Styrian Pumpkin Seed Oil has been approved with this label, but as with many other high priced regional specialities, fraud cannot be excluded or nor identified. Thus the aim of this work is, to develop an analytical method for the control of the geographic origin of pumpkin seed oil and also to test the method for other protected products. The development of such a method is not only of interest for scientists, but also of importance for the consumer wanting to know the origin of the food products and the assurance of the purity and quality. The group of rare earth elements (REE) in plants also have a characteristic distribution pattern similar to upper crustal REE distributions. Since the REE concentrations are extremely low in pumpkin seed oil (ppt to low ppb), ICP-MS was the only sensitive tool able to produce validated results. The carrier of the REE are most likely small particles distributed within the pumpkin seed oil. Unlike, e.g., olive oil, pumpkin seed oil is bottled and sold unfiltered, which makes this Styrian speciality an interesting sampling target. As pumpkin seed oils from different geographic origin show variable trace element and rare earth distribution patterns, is should possible to trace the origin of these oils. In the current project pumpkin seeds from different regions in Austria and from abroad were sampled. The trace element patterns in the extracted oil of these seeds were determined and a preliminary classification with discriminate analysis was successfully done on a statistical basis. In addition to the study of the geographic origin it was demonstrated that REE distribution patterns can also be used for the

  12. Rare earth elements (REEs): effects on germination and growth of selected crop and native plant species.

    PubMed

    Thomas, Philippe J; Carpenter, David; Boutin, Céline; Allison, Jane E

    2014-02-01

    The phytotoxicity of rare earth elements (REEs) is still poorly understood. The exposure-response relationships of three native Canadian plant species (common milkweed, Asclepias syriaca L., showy ticktrefoil, Desmodium canadense (L.) DC. and switchgrass, Panicum virgatum L.) and two commonly used crop species (radish, Raphanus sativus L., and tomato, Solanum lycopersicum L.) to the REEs lanthanum (La), yttrium (Y) and cerium (Ce) were tested. In separate experiments, seven to eight doses of each element were added to the soil prior to sowing seeds. Effects of REE dose on germination were established through measures of total percent germination and speed of germination; effects on growth were established through determination of above ground biomass. Ce was also tested at two pH levels and plant tissue analysis was conducted on pooled samples. Effects on germination were mostly observed with Ce at low pH. However, effects on growth were more pronounced, with detectable inhibition concentrations causing 10% and 25% reductions in biomass for the two native forb species (A. syriaca and D. canadense) with all REEs and on all species tested with Ce in both soil pH treatments. Concentration of Ce in aboveground biomass was lower than root Ce content, and followed the dose-response trend. From values measured in natural soils around the world, our results continue to support the notion that REEs are of limited toxicity and not considered extremely hazardous to the environment. However, in areas where REE contamination is likely, the slow accumulation of these elements in the environment could become problematic. PMID:23978671

  13. Rare earth and high field strength element partitioning between iron-rich clinopyroxenes and felsic liquids

    NASA Astrophysics Data System (ADS)

    Olin, P. H.; Wolff, J. A.

    2010-11-01

    Rare earth elements are commonly assumed to substitute only for Ca in clinopyroxene because of the similarity of ionic radii for REE3+ and Ca2+ in eightfold coordination. The assumption is valid for Mg-rich clinopyroxenes for which observed mineral/melt partition coefficients are readily predicted by the lattice strain model for substitution onto a single site (e.g., Wood and Blundy 1997). We show that natural Fe-rich pyroxenes in both silica-undersaturated and silica-oversaturated magmatic systems deviate from this behavior. Salites (Mg# 48-59) in phonolites from Tenerife, ferrohedenbergites (Mg# 14.2-16.2) from the rhyolitic Bandelier Tuff, and ferroaugites (Mg# 9.6-32) from the rhyolitic Rattlesnake Tuff have higher heavy REE contents than predicted by single-site substitution. The ionic radius of Fe2+ in sixfold coordination is substantially greater than that of Mg2+; hence, we propose that, in Fe-rich clinopyroxenes, heavy REE are significantly partitioned between eightfold Ca sites and sixfold Fe and Mg sites such that Yb and Lu exist dominantly in sixfold coordination. We also outline a REE-based method of identifying pyroxene/melt pairs in systems with multiple liquid and crystal populations, based upon the assumption that LREE and MREE reside exclusively in eightfold coordination in pyroxene. Contrary to expectations, interpolation of mineral/melt partition coefficient data for heavy REE does not predict the behavior of Y. We speculate that mass fractionation effects play a role in mineral/melt lithophile trace element partitioning that is detectable among pairs of isovalent elements with near-identical radii, such as Y and Ho, Zr and Hf, and Nb and Ta.

  14. Rare earth elements minimal harvest year variation facilitates robust geographical origin discrimination: The case of PDO "Fava Santorinis".

    PubMed

    Drivelos, Spiros A; Danezis, Georgios P; Haroutounian, Serkos A; Georgiou, Constantinos A

    2016-12-15

    This study examines the trace and rare earth elemental (REE) fingerprint variations of PDO (Protected Designation of Origin) "Fava Santorinis" over three consecutive harvesting years (2011-2013). Classification of samples in harvesting years was studied by performing discriminant analysis (DA), k nearest neighbours (κ-NN), partial least squares (PLS) analysis and probabilistic neural networks (PNN) using rare earth elements and trace metals determined using ICP-MS. DA performed better than κ-NN, producing 100% discrimination using trace elements and 79% using REEs. PLS was found to be superior to PNN, achieving 99% and 90% classification for trace and REEs, respectively, while PNN achieved 96% and 71% classification for trace and REEs, respectively. The information obtained using REEs did not enhance classification, indicating that REEs vary minimally per harvesting year, providing robust geographical origin discrimination. The results show that seasonal patterns can occur in the elemental composition of "Fava Santorinis", probably reflecting seasonality of climate. PMID:27451177

  15. Carbon and other light element contents in the Earth's core based on first-principles molecular dynamics.

    PubMed

    Zhang, Yigang; Yin, Qing-Zhu

    2012-11-27

    Carbon (C) is one of the candidate light elements proposed to account for the density deficit of the Earth's core. In addition, C significantly affects siderophile and chalcophile element partitioning between metal and silicate and thus the distribution of these elements in the Earth's core and mantle. Derivation of the accretion and core-mantle segregation history of the Earth requires, therefore, an accurate knowledge of the C abundance in the Earth's core. Previous estimates of the C content of the core differ by a factor of ∼20 due to differences in assumptions and methods, and because the metal-silicate partition coefficient of C was previously unknown. Here we use two-phase first-principles molecular dynamics to derive this partition coefficient of C between liquid iron and silicate melt. We calculate a value of 9 ± 3 at 3,200 K and 40 GPa. Using this partition coefficient and the most recent estimates of bulk Earth or mantle C contents, we infer that the Earth's core contains 0.1-0.7 wt% of C. Carbon thus plays a moderate role in the density deficit of the core and in the distribution of siderophile and chalcophile elements during core-mantle segregation processes. The partition coefficients of nitrogen (N), hydrogen, helium, phosphorus, magnesium, oxygen, and silicon are also inferred and found to be in close agreement with experiments and other geochemical constraints. Contents of these elements in the core derived from applying these partition coefficients match those derived by using the cosmochemical volatility curve and geochemical mass balance arguments. N is an exception, indicating its retention in a mantle phase instead of in the core. PMID:23150591

  16. Ligand extraction of rare earth elements from aquifer sediments: Implications for rare earth element complexation with organic matter in natural waters

    NASA Astrophysics Data System (ADS)

    Tang, Jianwu; Johannesson, Karen H.

    2010-12-01

    The ability of organic matter as well as carbonate ions to extract rare earth elements (REEs) from sandy sediments of a Coastal Plain aquifer was investigated for unpurified organic matter from different sources (i.e., Mississippi River natural organic matter, Aldrich humic acid, Nordic aquatic fulvic acid, Suwannee River fulvic acid, and Suwannee River natural organic matter) and for extraction solutions containing weak (i.e., CH 3COO -) or strong (i.e., CO32-) ligands. The experimental results indicate that, in the absence of strong REE complexing ligands in solution, the amount of REEs released from the sand is small and the fractionation pattern of the released REEs appears to be controlled by the surface stability constants for REE sorption with Fe(III) oxides/oxyhydroxides. In the presence of strong solution complexing ligands, however, the amount and the fractionation pattern of the released REEs reflect the strength and variation of the stability constants of the dominant aqueous REE species across the REE series. The varying amount of REEs extracted by the different organic matter employed in the experiments indicates that organic matter from different sources has different complexing capacity for REEs. However, the fractionation pattern of REEs extracted by the various organic matter used in our experiments is remarkable consistent, being independent of the source and the concentration of organic matter used, as well as solution pH. Because natural aquifer sand and unpurified organic matter were used in our experiments, our experimental conditions are more broadly similar to natural systems than many previous laboratory experiments of REE-humic complexation that employed purified humic substances. Our results suggest that the REE loading effect on REE-humic complexation is negligible in natural waters as more abundant metal cations (e.g., Fe, Al) out-compete REEs for strong binding sites on organic matter. More specifically, our results indicate that REE

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

    SciTech Connect

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

    2015-08-15

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

  18. Efficient mobilization and fractionation of rare-earth elements by aqueous fluids upon slab dehydration

    NASA Astrophysics Data System (ADS)

    Tsay, A.; Zajacz, Z.; Sanchez-Valle, C.

    2014-07-01

    The characteristic REE fractionation pattern in arc magmas compared to MOR-basalts results from the selective mobilization of light rare-earth elements (LREE) by slab-derived mobile components. However, the nature and composition of the slab flux, and the actual mechanisms responsible for the transfer of rare-earth elements (REE) from the slab to the mantle wedge remain unclear. We present experimental data on the solubility of selected REE in ligand-bearing aqueous fluids and a hydrous haplogranitic melt at 2.6 GPa and 600-800 °C, spanning the conditions relevant to slab dehydration and melting. The solubilities of REE in aqueous fluids increase more than an order of magnitude with temperature increasing from 600 to 800 °C. Addition of ligands such as Cl-, F-, CO32-, SO42- in relatively small concentrations (0.3-1.5 m [mol/kg H2O]) has a pronounced effect further enhancing REE solubilities. Each ligand yields a characteristic REE pattern by preferential dissolution of either the light or the heavy REE. For example, the addition of NaCl to the aqueous fluids yields highly elevated LREE/HREE ratios (La/Yb=17.4±4.3), whereas the addition of fluoride and sulfate ligands significantly increases the solubility of all REE with moderate LREE/HREE fractionation (La/Yb∼4). The addition of Na2CO3 results in preferential increase of HREE solubilities, and yields La/Yb ratio of 1.6±0.5 by flattening the moderately fractionated REE pattern seen in pure aqueous fluids. The solubilities in hydrous haplogranite melt are moderate in comparison to those observed in aqueous fluids and do not lead to pronounced REE fractionation. Therefore, REE can be effectively mobilized and fractionated by aqueous fluids, compared to felsic hydrous melts. Furthermore, the aqueous fluid chemistry has a major role in determining REE mobilities and fractionation upon slab dehydration in addition to the significant control exerted by temperature. Our results show that chloride-bearing slab

  19. Rare earth elements and neodymium isotopes in world river sediments revisited

    NASA Astrophysics Data System (ADS)

    Bayon, G.; Toucanne, S.; Skonieczny, C.; André, L.; Bermell, S.; Cheron, S.; Dennielou, B.; Etoubleau, J.; Freslon, N.; Gauchery, T.; Germain, Y.; Jorry, S. J.; Ménot, G.; Monin, L.; Ponzevera, E.; Rouget, M.-L.; Tachikawa, K.; Barrat, J. A.

    2015-12-01

    Over the past decades, rare earth elements (REE) and their radioactive isotopes have received tremendous attention in sedimentary geochemistry, as tracers for the geological history of the continental crust and provenance studies. In this study, we report on elemental concentrations and neodymium (Nd) isotopic compositions for a large number of sediments collected near the mouth of rivers worldwide, including some of the world's major rivers. Sediments were leached for removal of non-detrital components, and both clay and silt fractions were retained for separate geochemical analyses. Our aim was to re-examine, at the scale of a large systematic survey, whether or not REE and Nd isotopes could be fractionated during Earth surface processes. Our results confirmed earlier assumptions that river sediments do not generally exhibit any significant grain-size dependent Nd isotopic variability. Most sediments from rivers draining old cratonic areas, sedimentary systems and volcanic provinces displayed similar Nd isotopic signatures in both clay and silt fractions, with ΔεNd(clay-silt) < |1|. A subtle decoupling of Nd isotopes between clays and silts was identified however in a few major river systems (e.g. Nile, Mississippi, Fraser), with clays being systematically shifted towards more radiogenic values. This observation suggests that preferential weathering of volcanic and/or sedimentary rocks relative to more resistant lithologies may occur in river basins, possibly leading locally to Nd isotopic decoupling between different size fractions. Except for volcanogenic sediments, silt fractions generally displayed homogeneous REE concentrations, exhibiting relatively flat shale-normalized patterns. However, clay fractions were almost systematically characterized by a progressive enrichment from the heavy to the light REE and a positive europium (Eu) anomaly. In agreement with results from previous soil investigations, the observed REE fractionation between clays and silts

  20. Rare-earth elements enrichment of Pacific seafloor sediments: the view from volcanic islands of Polynesia

    NASA Astrophysics Data System (ADS)

    Melleton, Jérémie; Tuduri, Johann; Pourret, Olivier; Bailly, Laurent; Gisbert, Thierry

    2014-05-01

    Rare-earth elements (REEs) are key metals for «green» technologies such as energy saving lamps or permanent magnets used in, e.g., wind turbines, hard disk drives, portable phone or electric or hybrid vehicles. Since several years, world demand for these metals is therefore drastically increasing. The quasi-monopolistic position of China, which produces around 95 % of global REEs production, generates risks for the industries that depend on a secure supply of REEs. In response, countries are developing and diversifying their supply sources, with new mining projects located outside China and efforts in the area of REEs recycling. Most of these projects focus on deposits related to carbonatites and alkaline-peralkaline magmatism, which are generally enriched in light REEs (LREEs) compared to the heavy REEs (HREEs)-enriched deposits of the ion-adsorption types, located in southern China. However, a recent study revealed new valuable resources corresponding to seafloor sediments located in the south-eastern and north-central Pacific. The deep-sea mud described by these authors show a higher HREE/LREE ratio than ion-adsorption deposits, a feature which significantly increases their economic interest. The authors suggest mid-ocean ridge hydrothermal activity as an explanation to this anomalous enrichment. However, several contributions have documented considerable REEs enrichment in basalts and peridotitic xenoliths from French Polynesia. Several arguments have been exposed in favour of a supergene origin, with a short migration, suggesting that REEs were collected from weathered basalts. The Tahaa volcanic island (Sous-le-Vent Island, Society Archipelago, French Polynesia) is the first location where such enrichment has been described. New petrographic and mineralogical investigations confirm a supergene mobilization of this abnormal occurrence. REE-bearing minerals (mainly phosphates of the rhabdophane group) are primarily located within basalt vesicles but also in

  1. Utilizing rare earth elements as tracers in high TDS reservoir brines in CCS applications

    SciTech Connect

    McLing, Travis; Smith, William; Smith, Robert

    2014-12-31

    In this paper we report the result of research associated with the testing of a procedures necessary for utilizing natural occurring trace elements, specifically the Rare Earth Elements (REE) as geochemical tracers in Carbon Capture and Storage (CCS) applications. Trace elements, particularly REE may be well suited to serve as in situ tracers for monitoring geochemical conditions and the migration of CO₂-charged waters within CCS storage systems. We have been conducting studies to determine the efficacy of using REE as a tracer and characterization tool in the laboratory, at a CCS analogue site in Soda Springs, Idaho, and at a proposed CCS reservoir at the Rock Springs Uplift, Wyoming. Results from field and laboratory studies have been encouraging and show that REE may be an effective tracer in CCS systems and overlying aquifers. In recent years, a series of studies using REE as a natural groundwater tracer have been conducted successfully at various locations around the globe. Additionally, REE and other trace elements have been successfully used as in situ tracers to describe the evolution of deep sedimentary Basins. Our goal has been to establish naturally occurring REE as a useful monitoring measuring and verification (MMV) tool in CCS research because formation brine chemistry will be particularly sensitive to changes in local equilibrium caused by the addition of large volumes of CO₂. Because brine within CCS target formations will have been in chemical equilibrium with the host rocks for millions of years, the addition of large volumes of CO₂ will cause reactions in the formation that will drive changes to the brine chemistry due to the pH change caused by the formation of carbonic acid. This CO₂ driven change in formation fluid chemistry will have a major impact on water rock reaction equilibrium in the formation, which will impart a change in the REE fingerprint of the brine that can measured and be used to monitor in situ

  2. Utilizing rare earth elements as tracers in high TDS reservoir brines in CCS applications

    DOE PAGESBeta

    McLing, Travis; Smith, William; Smith, Robert

    2014-12-31

    In this paper we report the result of research associated with the testing of a procedures necessary for utilizing natural occurring trace elements, specifically the Rare Earth Elements (REE) as geochemical tracers in Carbon Capture and Storage (CCS) applications. Trace elements, particularly REE may be well suited to serve as in situ tracers for monitoring geochemical conditions and the migration of CO₂-charged waters within CCS storage systems. We have been conducting studies to determine the efficacy of using REE as a tracer and characterization tool in the laboratory, at a CCS analogue site in Soda Springs, Idaho, and at amore » proposed CCS reservoir at the Rock Springs Uplift, Wyoming. Results from field and laboratory studies have been encouraging and show that REE may be an effective tracer in CCS systems and overlying aquifers. In recent years, a series of studies using REE as a natural groundwater tracer have been conducted successfully at various locations around the globe. Additionally, REE and other trace elements have been successfully used as in situ tracers to describe the evolution of deep sedimentary Basins. Our goal has been to establish naturally occurring REE as a useful monitoring measuring and verification (MMV) tool in CCS research because formation brine chemistry will be particularly sensitive to changes in local equilibrium caused by the addition of large volumes of CO₂. Because brine within CCS target formations will have been in chemical equilibrium with the host rocks for millions of years, the addition of large volumes of CO₂ will cause reactions in the formation that will drive changes to the brine chemistry due to the pH change caused by the formation of carbonic acid. This CO₂ driven change in formation fluid chemistry will have a major impact on water rock reaction equilibrium in the formation, which will impart a change in the REE fingerprint of the brine that can measured and be used to monitor in situ reservoir

  3. Drill core major, trace and rare earth element anlayses from wells RN-17B and RN-30, Reykjanes, Iceland

    DOE Data Explorer

    Andrew Fowler

    2015-04-01

    Analytical results for X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) measurement of major, trace and rare earth elements in drill core from geothermal wells in Reykjanes, Iceland. Total Fe was analyzed as FeO, therefore is not included under the Fe2O3 column.

  4. Using Rare Earth Element (REE) tracers to identify perferential micro-sites of post-fire aeolian erosion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant communities in desert environments are spatially anisotropic. We applied Rare Earth Element (REE) tracers to different landscape positions of an anisotropic Northern Chihuahua Desert ecosystem in an effort to study preferential sediment source areas. We delineated three 0.5 m by 6 m plots of...

  5. Using commercial finite element packages for the study of earth deformations, sea levels and the state of stress

    NASA Astrophysics Data System (ADS)

    Wu, Patrick

    2004-08-01

    Modifications to commercial finite element (FE) packages must be applied before they can be used for geophysical studies involving long wavelength deformation or viscoelasticity. This paper provides in detail how and why the commercial codes have to be modified when incompressibility is assumed. Both the non-self-gravitating flat earth and self-gravitating spherical earth will be considered. The latter involves an iterative procedure, which converges within 5 iterations. This is demonstrated both analytically and numerically. In addition, implementation of the gravitationally self-consistent sea level equation on a self-gravitating spherical earth is also described. Good agreement between numerical results obtained with this coupled finite-element method and the conventional spectral method is also demonstrated. In all cases, the interpretation of the outputs of FE models are particularly important in modelling the state of stress.

  6. A chemical-spectrochemical method for the determination of rare earth elements and thorium in cerium minerals

    USGS Publications Warehouse

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

    1954-01-01

    In a combined chemical-spectrochemical procedure for quantitatively determining rare earth elements in cerium minerals, cerium is determined volumetrically, a total rare earths plus thoria precipitate is separated chemically, the ceria content of the precipitate is raised to 80??0 percent by adding pure ceria, and the resulting mixture is analyzed for lanthanum, praseodymium, neodymium, samarium, gadolinium, yttrium, and thorium spectrochemically by means of the d.c. carbon arc. Spectral lines of singly ionized cerium are used as internal standard lines in the spectrochemical determination which is patterned after Fassel's procedure [1]. Results of testing the method with synthetic mixtures of rare earths and with samples of chemically analyzed cerium minerals show that the coefficient of variation for a quadruplicate determination of any element does not exceed 5??0 (excepting yttrium at concentrations less than 1 percent) and that the method is free of serious systematic error. ?? 1954.

  7. Trends in the Rare Earth Element Content of U.S.-Based Coal Combustion Fly Ashes.

    PubMed

    Taggart, Ross K; Hower, James C; Dwyer, Gary S; Hsu-Kim, Heileen

    2016-06-01

    Rare earth elements (REEs) are critical and strategic materials in the defense, energy, electronics, and automotive industries. The reclamation of REEs from coal combustion fly ash has been proposed as a way to supplement REE mining. However, the typical REE contents in coal fly ash, particularly in the United States, have not been comprehensively documented or compared among the major types of coal feedstocks that determine fly ash composition. The objective of this study was to characterize a broad selection of U.S. fly ashes of varied geological origin in order to rank their potential for REE recovery. The total and nitric acid-extractable REE content for more than 100 ash samples were correlated with characteristics such as the major element content and coal basin to elucidate trends in REE enrichment. Average total REE content (defined as the sum of the lanthanides, yttrium, and scandium) for ashes derived from Appalachian sources was 591 mg kg(-1) and significantly greater than in ashes from Illinois and Powder River basin coals (403 and 337 mg kg(-1), respectively). The fraction of critical REEs (Nd, Eu, Tb, Dy, Y, and Er) in the fly ashes was 34-38% of the total and considerably higher than in conventional ores (typically less than 15%). Powder River Basin ashes had the highest extractable REE content, with 70% of the total REE recovered by heated nitric acid digestion. This is likely due to the higher calcium content of Powder River Basin ashes, which enhances their solubility in nitric acid. Sc, Nd, and Dy were the major contributors to the total REE value in fly ash, based on their contents and recent market prices. Overall, this study shows that coal fly ash production could provide a substantial domestic supply of REEs, but the feasibility of recovery depends on the development of extraction technologies that could be tailored to the major mineral content and origins of the feed coal for the ash. PMID:27228215

  8. Health effects and toxicity mechanisms of rare earth elements-Knowledge gaps and research prospects.

    PubMed

    Pagano, Giovanni; Guida, Marco; Tommasi, Franca; Oral, Rahime

    2015-05-01

    In the recent decades, rare earth elements (REE) have undergone a steady spread in several industrial and medical applications, and in agriculture. Relatively scarce information has been acquired to date on REE-associated biological effects, from studies of bioaccumulation and of bioassays on animal, plant and models; a few case reports have focused on human health effects following occupational REE exposures, in the present lack of epidemiological studies of occupationally exposed groups. The literature is mostly confined to reports on few REE, namely cerium and lanthanum, whereas substantial information gaps persist on the health effects of other REE. An established action mechanism in REE-associated health effects relates to modulating oxidative stress, analogous to the recognized redox mechanisms observed for other transition elements. Adverse outcomes of REE exposures include a number of endpoints, such as growth inhibition, cytogenetic effects, and organ-specific toxicity. An apparent controversy regarding REE-associated health effects relates to opposed data pointing to either favorable or adverse effects of REE exposures. Several studies have demonstrated that REE, like a number of other xenobiotics, follow hormetic concentration-related trends, implying stimulatory or protective effects at low levels, then adverse effects at higher concentrations. Another major role for REE-associated effects should be focused on pH-dependent REE speciation and hence toxicity. Few reports have demonstrated that environmental acidification enhances REE toxicity; these data may assume particular relevance in REE-polluted acidic soils and in REE mining areas characterized by concomitant REE and acid pollution. The likely environmental threats arising from REE exposures deserve a new line of research efforts. PMID:25679485

  9. Rare earth elements in the phosphatic-enriched sediment of the Peru shelf

    USGS Publications Warehouse

    Piper, D.Z.; Baedecker, P.A.; Crock, J.G.; Burnett, W.C.; Loebner, B.J.

    1988-01-01

    Apatite-enriched materials from the Peru shelf have been analyzed for their major oxide and rare earth element (REE) concentrations. The samples consist of (1) the fine fraction of sediment, mostly clay material, (2) phosphatic pellets and fish debris, which are dispersed throughout the fine-grained sediment, (3) tabular-shaped phosphatic crusts, which occur within the uppermost few centimeters of sediment, and (4) phosphatic nodules, which occur on the seafloor. The bulk REE concentrations of the concretions suggest that these elements are partitioned between the enclosed detrital material and the apatite fraction. Analysis of the fine-grained sediment with which the samples are associated suggested that this detrital fraction in the concretions should have shale REE values; the analysis of the fish debris suggested that the apatite fraction might have seawater values. The seawater contribution of REE's is negligible in the nodules and crust, in which the apatite occurs as a fine-grained interstitial cement. That is, the concentration of REE's and the REE patterns are predominantly a function of the amount of enclosed fine-grained sediment. By contrast, the REE pattern of the pelletal apatite suggests a seawater source and the absolute REE concentrations are relatively high. The REE P2O5 ratios of the apatite fraction of these samples thus vary from approximately zero (in the case of the crust and nodules) to as much as approximately 1.2 ?? 10-3 (in the case of the pellets). The range of this ratio suggests that rather subtle variations in the depositional environment might cause a significant variation in the REE content of this authigenic fraction of the sediment. Pelletal glauconite was also recovered from one sediment core. Its REE concentrations closely resemble those of the fish debris. ?? 1988.

  10. Developing alternative resources of rare earth elements in Europe - EURARE and the red mud challenge

    NASA Astrophysics Data System (ADS)

    Deady, Eimear; Mouchos, Evangelos; Goodenough, Kathryn; Wall, Frances; Williamson, Ben

    2015-04-01

    Rare earth elements (REE) are considered to be highly "critical" by the European Commission [1], owing to the concentration of global supply [2] and their use in a wide range of emerging technologies (e.g. smart phones, electric cars and wind turbines). The main source of REE is the mineral bastnäsite, which is primarily extracted from carbonatites. Alternative resources of REE have been identified in a variety of other environments such as alluvial placers, bauxites and ore tailings. The EURARE project (www.eurare.eu), funded by the European Commission, aims to improve understanding of potential REE resources in Europe with the overall objective of establishing the basis for a European REE industry. As a part of this project, alternative sources of rare earth elements in Europe are being considered. REE have been identified as being particularly enriched in karst-bauxites and hence in the red muds generated as a waste product from the processing of these bauxites to alumina through the Bayer process [3]. Karst-bauxites are widely distributed with deposits known across the Mediterranean and with intermittent exploitation occurring over many decades. REE become concentrated in the bauxite deposits by the bauxitisation process and are retained due to the geochemical barrier created by the limestone bedrock below. This can result in several processes, including the crystallisation of authigenic REE-bearing minerals, the accumulation of residual phases and the adsorption of ions onto clays and other mineral surfaces [4]. Red muds produced from alumina processing represent a potentially important concentration of REE as it has been demonstrated that the REE pass through the alumina extraction process into the waste, and the total REE concentrations are typically enriched by a factor of two compared with the original bauxite ore [5]. Bauxites and red muds from the Parnassus Ghiona region of Greece [6] and the Seydişehir-Akseki region of Turkey have been assessed as

  11. Rare earth element geochemistry of massive sulfides-sulfates and gossans on the Southern Explorer Ridge

    SciTech Connect

    Barrett, T.J. ); Jarvis, I. ); Jarvis, K.E. )

    1990-07-01

    Massive sulfide-sulfate deposits on the Southern Explorer Ridge were analyzed for 14 rare earth elements (REE) by a modified inductively coupled plasma-mass spectrometric technique that included a correction for high Ba content. Bulk samples of finely intermixed sulfides, sulfate, and amorphous silica contain {Sigma}REE concentrations of {le} 6 ppm. REE patterns range from (1) strongly enriched in light REE with positive Eu anomalies, to (2) relatively flat with positive Eu anomalies and slightly negative Ce anomalies, to (3) slightly enriched in light REE with moderately negative Ce anomalies. Pattern 1 is similar to that of 300-350 C solutions discharging at vents on the East Pacific Rise and the Mid-Atlantic Ridge, whereas pattern 3 resembles REE distributions in normal oceanic bottom waters. The sulfide-sulfate patterns are interpreted to result from variable mixtures of hydrothermal and normal seawater. Barite in gossans capping the mounds has an REE pattern almost identical to patterns of high-temperature vent solutions. Hydrothermal barite has lower REE contents and a different REE pattern relative to hydrogenous barite formed slowly on the sea floor.

  12. Determination of Rare Earth Elements in Hypersaline Solutions Using Low-Volume, Liquid-Liquid Extraction.

    PubMed

    Noack, Clinton W; Dzombak, David A; Karamalidis, Athanasios K

    2015-08-18

    Complex, hypersaline brines-including those coproduced with oil and gas, rejected from desalination technologies, or used as working fluids for geothermal electricity generation-could contain critical materials such as the rare earth elements (REE) in valuable concentrations. Accurate quantitation of these analytes in complex, aqueous matrices is necessary for evaluation and implementation of systems aimed at recovering those critical materials. However, most analytical methods for measuring trace metals have not been validated for highly saline and/or chemically complex brines. Here we modified and optimized previously published liquid-liquid extraction (LLE) techniques using bis(2-ethylhexyl) phosphate as the extractant in a heptane diluent, and studied its efficacy for REE recovery as a function of three primary variables: background salinity (as NaCl), concentration of a competing species (here Fe), and concentration of dissolved organic carbon (DOC). Results showed that the modified LLE was robust to a range of salinity, Fe, and DOC concentrations studied as well as constant, elevated Ba concentrations. With proper characterization of the natural samples of interest, this method could be deployed for accurate analysis of REE in small volumes of hyper-saline and chemically complex brines. PMID:25920439

  13. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration.

    PubMed

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency. PMID:26819083

  14. Composition and evolution of the eucrite parent body - Evidence from rare earth elements. [extraterrestrial basaltic melts

    NASA Technical Reports Server (NTRS)

    Consolmagno, G. J.; Drake, M. J.

    1977-01-01

    Quantitative modeling of the evolution of rare earth element (REE) abundances in the eucrites, which are plagioclase-pigeonite basalt achondrites, indicates that the main group of eucrites (e.g., Juvinas) might have been produced by approximately 10% equilibrium partial melting of a single type of source region with initial REE abundances which were chondritic relative and absolute. Since the age of the eucrites is about equal to that of the solar system, extensive chemical differentiation of the eucrite parent body prior to the formation of eucrites seems unlikely. If homogeneous accretion is assumed, the bulk composition of the eucrite parent body can be estimated; two estimates are provided, representing different hypotheses as to the ratio of metal to olivine in the parent body. Since a large number of differentiated olivine meteorites, which would represent material from the interior of the parent body, have not been detected, the eucrite parent body is thought to be intact. It is suggested that the asteroid 4 Vesta is the eucrite parent body.

  15. Uptake and effect of rare earth elements on gene expression in Methylosinus trichosporium OB3b.

    PubMed

    Gu, Wenyu; Farhan Ul Haque, Muhammad; DiSpirito, Alan A; Semrau, Jeremy D

    2016-07-01

    It is well known that Methylosinus trichosporium OB3b has two forms of methane monooxygenase (MMO) responsible for the initial conversion of methane to methanol, a cytoplasmic (soluble) methane monooxygenase and a membrane-associated (particulate) methane monooxygenase, and that copper strongly regulates expression of these alternative forms of MMO. More recently, it has been discovered that M. trichosporium OB3b has multiple types of the methanol dehydrogenase (MeDH), i.e. the Mxa-type MeDH (Mxa-MeDH) and Xox-type MeDH (Xox-MeDH), and the expression of these two forms is regulated by the availability of the rare earth element (REE), cerium. Here, we extend these studies and show that lanthanum, praseodymium, neodymium and samarium also regulate expression of alternative forms of MeDH. The effect of these REEs on MeDH expression, however, was only observed in the absence of copper. Further, a mutant of M. trichosporium OB3b, where the Mxa-MeDH was knocked out, was able to grow in the presence of lanthanum, praseodymium and neodymium, but was not able to grow in the presence of samarium. Collectively, these data suggest that multiple levels of gene regulation by metals exist in M. trichosporium OB3b, but that copper overrides the effect of other metals by an as yet unknown mechanism. PMID:27190151

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

    PubMed

    Butnariu, Monica; Negrea, Petru; Lupa, Lavinia; Ciopec, Mihaela; Negrea, Adina; Pentea, Marius; Sarac, Ionut; Samfira, Ionel

    2015-09-01

    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. PMID:26378553

  17. Determination of the rare-earth elements in geological materials by inductively coupled plasma mass spectrometry

    USGS Publications Warehouse

    Lichte, F.E.; Meier, A.L.; Crock, J.G.

    1987-01-01

    A method of analysis of geological materials for the determination of the rare-earth elements using the Inductively coupled plasma mass spectrometric technique (ICP-MS) has been developed. Instrumental parameters and factors affecting analytical results have been first studied and then optimized. Samples are analyzed directly following an acid digestion, without the need for separation or preconcentration with limits of detection of 2-11 ng/g, precision of ?? 2.5% relative standard deviation, and accuracy comparable to inductively coupled plasma emission spectrometry and instrumental neutron activation analysis. A commercially available ICP-MS instrument is used with modifications to the sample introduction system, torch, and sampler orifice to reduce the effects of high salt content of sample solutions prepared from geologic materials. Corrections for isobaric interferences from oxide ions and other diatomic and triatomic ions are made mathematically. Special internal standard procedures are used to compensate for drift in metahmetal oxide ratios and sensitivity. Reference standard values are used to verify the accuracy and utility of the method.

  18. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration

    PubMed Central

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency. PMID:26819083

  19. Rare-earth element variation in phosphate nodules from midcontinent Pennsylvanian cyclothems

    SciTech Connect

    Kidder, D.L. . Dept. of Geological Sciences); Eddy-Dilek, C.A. . Savannah River Technology Center)

    1994-07-01

    The rare-earth element (REE) geochemistry of phosphate nodules from eastern Kansas and northeastern Oklahoma is dominated by patterns that are generally flat or are enriched in middle REE (MREE). Flat patterns are typical of phosphate nodules preserved in thick shales and in nodules from shales deposited nearest to detrital sources. The flat patterns are probably derived from terrigenous constituents in the host shale. MREE enrichment is evident in phosphate found in relatively thin shales and in distal shales. The authors suggest that the MREE-enriched pattern reflects the contribution of MREE-enriched fecal phosphate. The initial MREE enrichment mechanism may have been analogous to that in which some modern algae preferentially extract MREE from water of marine composition. The MREE-enriched signature may be preserved only in phosphate nodules that formed where terrigenous input was so low that it did not mask the characteristic fecal pattern. Rare Ce depletion patterns reflect a primary seawater REE source that has not been obscured by fecal or detrital components.

  20. The geochemistry of rare earth elements in the Amazon River estuary

    SciTech Connect

    Shokovitz, E.R. )

    1993-05-01

    The estuarine geochemistry of rare earth elements (REEs) was studied using samples collected in the Amazon River estuary from the AmasSeds (Amazon Shelf SEDiment Study) cruise of August 1989. Extensive removal of dissolved (0.22 [mu]m filtered) trivalent REEs from river water occurs in the low (0--6) salinity region. Removal by the salt-induced coagulation of river colloids leads to fractionation among the REE(III) series; the order of removal is light REEs > middle REEs > heavy REEs. There also is the enhanced removal of Ce (relative to trivalent La and Nd) in the low salinity (0--6) zone and in the zone of high biological activity. This is the first field observation of strong Ce removal associated with coagulation of river colloids and biological productivity. The argument is made that the decrease in the Ce anomaly across a biological front is caused by biologically mediated oxidation of Ce(III) to Ce(IV). Coagulation of river colloids and biologically mediated oxidation of Ce(III) lead to fractionation of REE(III) and redox modification of Ce. These processes result in the REE composition becoming fractionated relative to the Amazon River water and crust and more evolved toward the REE composition of the oceans. This study implies that reactions in estuaries play significant, yet poorly understood roles in controlling the REE composition and Ce anomaly of the oceans. 46 refs., 9 figs., 2 tabs.

  1. New Fission Fragment Distributions and r-Process Origin of the Rare-Earth Elements

    NASA Astrophysics Data System (ADS)

    Goriely, S.; Sida, J.-L.; Lemaître, J.-F.; Panebianco, S.; Dubray, N.; Hilaire, S.; Bauswein, A.; Janka, H.-T.

    2013-12-01

    Neutron star (NS) merger ejecta offer a viable site for the production of heavy r-process elements with nuclear mass numbers A≳140. The crucial role of fission recycling is responsible for the robustness of this site against many astrophysical uncertainties, but calculations sensitively depend on nuclear physics. In particular, the fission fragment yields determine the creation of 110≲A≲170 nuclei. Here, we apply a new scission-point model, called SPY, to derive the fission fragment distribution (FFD) of all relevant neutron-rich, fissioning nuclei. The model predicts a doubly asymmetric FFD in the abundant A≃278 mass region that is responsible for the final recycling of the fissioning material. Using ejecta conditions based on relativistic NS merger calculations, we show that this specific FFD leads to a production of the A≃165 rare-earth peak that is nicely compatible with the abundance patterns in the Sun and metal-poor stars. This new finding further strengthens the case of NS mergers as possible dominant origin of r nuclei with A≳140.

  2. Rare earth element partitioning between hydrous ferric oxides and acid mine water during iron oxidation

    USGS Publications Warehouse

    Verplanck, P.L.; Nordstrom, D.K.; Taylor, H.E.; Kimball, B.A.

    2004-01-01

    Ferrous iron rapidly oxidizes to Fe (III) and precipitates as hydrous Fe (III) oxides in acid mine waters. This study examines the effect of Fe precipitation on the rare earth element (REE) geochemistry of acid mine waters to determine the pH range over which REEs behave conservatively and the range over which attenuation and fractionation occur. Two field studies were designed to investigate REE attenuation during Fe oxidation in acidic, alpine surface waters. To complement these field studies, a suite of six acid mine waters with a pH range from 1.6 to 6.1 were collected and allowed to oxidize in the laboratory at ambient conditions to determine the partitioning of REEs during Fe oxidation and precipitation. Results from field experiments document that even with substantial Fe oxidation, the REEs remain dissolved in acid, sulfate waters with pH below 5.1. Between pH 5.1 and 6.6 the REEs partitioned to the solid phases in the water column, and heavy REEs were preferentially removed compared to light REEs. Laboratory experiments corroborated field data with the most solid-phase partitioning occurring in the waters with the highest pH. ?? 2004 Elsevier Ltd. All rights reserved.

  3. Microwave absorbing properties of rare-earth elements substituted W-type barium ferrite

    NASA Astrophysics Data System (ADS)

    Jing, Wang; Hong, Zhang; Shuxin, Bai; Ke, Chen; Changrui, Zhang

    2007-05-01

    W-type barium ferrites Ba(MnZn) 0.3Co 1.4R 0.01Fe 15.99O 27 with R=Dy, Nd and Pr were prepared by chemical coprecipitation method. Effects of rare-earth elements (RE) substitution on microstructural and electromagnetic properties were analyzed. The results show that a small amount of RE 3+ ions can replace Fe 3+ ions and adjust hyperfine parameters. An obvious increase in natural resonance frequency and high frequency relaxation, and a sharp decrease for complex permittivity have been observed. Furthermore, the matching thickness and the reflection loss (RL) of one-layer ferrite absorber were calculated. It reveals that thin and broad-band can be obtained by RE-substitution. But only when the magnetic moment of RE 3+ is higher than that of Fe 3+, can substitution be effective for higher RL. Dy-substituted ferrite composite has excellent microwave absorption properties. The frequency (with respect to -10 dB RL) begins from 9.9 GHz, and the bandwidth reaches far more than 8.16 GHz. The peak value is -51.92 dB at a matching thickness of 2.1 mm.

  4. Rare earth element geochemistry of outcrop and core samples from the Marcellus Shale

    SciTech Connect

    Noack, Clinton W.; Jain, Jinesh C.; Stegmeier, John; Hakala, J. Alexandra; Karamalidis, Athanasios K.

    2015-06-26

    In this paper, we studied the geochemistry of the rare earth elements (REE) in eleven outcrop samples and six, depth-interval samples of a core from the Marcellus Shale. The REE are classically applied analytes for investigating depositional environments and inferring geochemical processes, making them of interest as potential, naturally occurring indicators of fluid sources as well as indicators of geochemical processes in solid waste disposal. However, little is known of the REE occurrence in the Marcellus Shale or its produced waters, and this study represents one of the first, thorough characterizations of the REE in the Marcellus Shale. In these samples, the abundance of REE and the fractionation of REE profiles were correlated with different mineral components of the shale. Namely, samples with a larger clay component were inferred to have higher absolute concentrations of REE but have less distinctive patterns. Conversely, samples with larger carbonate fractions exhibited a greater degree of fractionation, albeit with lower total abundance. Further study is necessary to determine release mechanisms, as well as REE fate-and-transport, however these results have implications for future brine and solid waste management applications.

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

    PubMed Central

    Butnariu, Monica; Negrea, Petru; Lupa, Lavinia; Ciopec, Mihaela; Negrea, Adina; Pentea, Marius; Sarac, Ionut; Samfira, Ionel

    2015-01-01

    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. PMID:26378553

  6. Rare-earth elements distribution in granulite-facies marbles: a witness of fluid rock interaction

    NASA Astrophysics Data System (ADS)

    Boulvais, Philippe; Fourcade, Serge; Moine, Bernard; Gruau, Gérard; Cuney, Michel

    2000-08-01

    The rare earth element (REE) distribution of marbles from Tranomaro (SE Madagascar) shows that the marbles have interacted with syn-metamorphic fluids during the Panafrican granulite-facies metamorphism. The Tranomaro area is characterized by an extensive development of pyroxenites (skarns) variably mineralized in uranothorianite and enriched in REE, Zr. Across a meter-scale marble-pyroxenite contact, the REE content increases from the most remote marble sample to the contact with the pyroxenite (La from 19.8 to 129 ppm). REE patterns in enriched marbles display a strong negative Eu anomaly similar to those of pyroxenites. This peculiar type of REE distribution results from fluid infiltration. On a regional scale, some marbles have similar REE characteristics (progressive development of Eu anomaly together with REE enrichment) showing that some of them have interacted with fluids. Infiltration was hardly recognizable using C and O isotopic signatures because large isotopic variations were introduced during the pre-granulitic history. Then, REE distribution in high-grade marble may be helpful in monitoring syn-metamorphic fluid flow. In the present case, it is a more reliable tracer of fluid infiltration than stable isotopic compositions.

  7. Elements of a new Global Water Strategy for the Group on Earth Observations

    NASA Astrophysics Data System (ADS)

    Lawford, Richard; Koike, Toshio; Ochiai, Osamu; Cripe, Douglas

    2013-04-01

    In order to address the need to review the scope and direction of GEO activities related to water and to provide guidance for the post-2015 GEO planning, the Integrated Global Water Cycle Observations (IGWCO) Community of Practice and the Committee on Earth Observation Satellites (CEOS) are working together to develop a strategy for GEO water activities over the next decade. This presentation will review the elements of the strategy which include topics as comprehensive as user needs and engagement, water cycle observational systems, assessment of water quality, data issues, interoperability and integration of water information systems and capacity building. Impediments in the flow of information and technological capabilities from the providers of new technologies, innovations and data products to the end users will be explored in terms of the nature of these impediments and how they can be overcome. To be successful in GEO's framework of volunteerism, the water strategy should build on activities that are on-going in related programmes at the international and national levels. In addition, implementation of the strategy will need to be supported through new initiatives and policies that promote greater integration. Suggestions for achieving these goals will be outlined at the end of the talk.

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

    SciTech Connect

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

    2015-06-24

    In this paper, 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. Finally, 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.

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

    DOE PAGESBeta

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

    2015-06-24

    In this paper, 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 acidmore » 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. Finally, 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.« less

  10. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration

    NASA Astrophysics Data System (ADS)

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency.