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Sample records for earth elements thorium

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

    International Nuclear Information System (INIS)

    Biswas, Sujoy; Rupawate, V.H.; Hareendran, K.N.; Roy, S.B.

    2014-01-01

    A new process based on solvent extraction has been developed for separation of uranium, thorium and rare earths from monazite leach solution using organophosphorous extractants. The Thorium cake coming from monazite source was dissolved in HNO 3 medium in presence of trace amount of HF for feed preparation. The separation of U(VI) was carried out by liquid-liquid extraction using tris-2-ethyl hexyl phosphoric acid (TEHP) in dodecane leaving thorium and rare earths elements in the raffinate. The thorium from raffinate was selectively extracted using 1M tri iso amyl phosphate (TiAP) in dodecane in organic phase leaving all rare earths elements in aqueous solution. The uranium and thorium from organic medium was quantitatively stripped using 0.05 M HNO 3 counter current mode. Results indicate the quantitative separation of uranium, thorium and rare earths from thorium cake (monazite source) using organophosphorous extractant in counter current mode

  2. Thorium and rare earth elements in crystal and brown sugar consumed in Brazil and Argentina

    International Nuclear Information System (INIS)

    Salles, Paula M.B. de; Campos, Tarcisio P. R. de

    2015-01-01

    Human exposure to contaminants in foods is a matter of general health concern. There is a growing interest in determine and quantify contaminants in food chain including natural radionuclides and rare earth elements (REE). Irradiation effects of radioactive nuclides and REE may cause lesions from their interaction with the human body. This study aimed to identify the presence of thorium and rare earth elements in crystal and brown sugar samples available for consumption in Brazil and Argentina. To determine the chemical elements, the 5g-sample methodology established at CDTN/CNEN, in Belo Horizonte, using the neutron activation technique, k 0 -method, was applied. The element Sm was determined in crystal sugar samples analyzed that were available to consumption in both countries. Similarly to the brown sugar samples which presented La, Sc and Sm. The elements Ce and Th were found in brown sugar sample available to consumption in Brazil. Thus, the detection of these elements in sugar samples is important insofar as the increasing consumption of sugar around the world. The presence of impurities and its concentration may contribute to health issues to consumers. (author)

  3. Uranium, thorium and rare earth elements distribution from different iron quadrangle spring waters

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Cláudia A.; Palmieri, Helena E.L.; Menezes, Maria A. de B.C.; Rodrigues, Paulo C.H., E-mail: cferreiraquimica@yahoo.com.br, E-mail: help@cdtn.br, E-mail: menezes@cdtn.br, E-mail: pchr@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-11-01

    This study was conducted to evaluate the concentrations of thorium, uranium and the rare earth elements (REE) in 26 spring waters, as well as the patterns of the REE of the samples from the Cercadinho, Moeda and Caue aquifers in different municipalities of the Iron Quadrangle (Quadrilatero Ferrifero), located in the central-southeast of Minas Gerais state. The pH value of the ground waters ranged from 3.8 to 7.0, indicating an acid nature of most of the spring waters. The investigation of REE speciation showed that all the REEs exist in the free X{sup 3+} ionic forms, under the prevailing Eh and pH conditions. In the studied samples the uranium concentrations (<2.3-1176 ng L{sup -1}) were below the guideline level set by Brazilian legislation (Ministry of Health 518- 03/2004). Thorium concentrations ranged from <0.39-11.0 ng L{sup -1} and the sum of the REE ranged from 6.0 to 37657 ng L{sup -1}. As there are no permissible limits related for the REE and thorium for different water quality standards in Brazil, more attention must be paid to the local residents' health risk caused by spring waters (REEs were > 1000 ng L{sup -1}) originating from aquifers located in Sabara, Barao de Cocais, Santa Barbara, Mario Campos, Congonhas and Lavras Novas. The REEs patterns in the spring waters from the Cercadinho, Caue and Moeda aquifers are characterized by middle REE (MREE) enrichment compared to light REE (LREE) and heavy REEs (HREE), negative Ce anomalies (except for one sample) and positive Eu anomalies in all three aquifers studied. (author)

  4. Study of rare earth elements, uranium and thorium migration in rocks from Espinharas uranium deposit, Paraiba - Brazil

    International Nuclear Information System (INIS)

    Conceicao, Cirilo C.S.

    2009-01-01

    The determination of rare earth elements as natural analogue in patterns geologic has grown as a tool for predicting the long-term safety of nuclear disposal in geological formation. Migration of natural radionuclides is one of the most serious problems in the waste deposit from nuclear fuel cycle. Rare earth elements show the same kinetic behavior in rocks as natural radionuclides. This similar property of the analogues allows perform studies and models on the subject of radionuclides migration. The aim of this study was to determine the distribution of rare earth elements in rocks located at Espinharas - Paraiba - Brazil, uranium deposit. In this work are presented the results from the study above the distribution of rare earth elements in function of the degree of mineralized rocks, composition and the conditions of radioactive equilibrium of the uranium and thorium in some fractures on the rocks from radioactive occurrence of Espinharas-Brazil. The results show that there is a correlation of heavy rare earth elements, uranium and Thorium concentrations to oxidation factor of the rocks. However this correlation was not observed for light rare earth elements. It means that heavy rare earth elements follow the natural radionuclides in oxidation process of rocks. The samples were analyzed by ICP-MS, alpha and gamma spectrometry, X-ray diffraction and fluorimetry. (author)

  5. Process for the separation of thorium and rare earths from a fluoride concentrate containing these elements

    International Nuclear Information System (INIS)

    Cailly, F.; Fabre, F.

    1989-01-01

    The concentrate is attacked by a solution of sodium hydroxide in a quantity of at least 1.4 times the stoichiometry and with a concentration between 1 and 40 wt%. A precipitate of thorium hydroxide and rare earth hydroxide is obtained with a solution of sodium fluoride. Th and RE are separated by acid dissolution and selective precipitation or solvent extraction [fr

  6. Behavior and distribution of rare earth elements, thorium and uranium in soil environment

    International Nuclear Information System (INIS)

    Kano, Naoki; Ogura, Daichi; Imaizumi, Hiroshi; Tsuchida, Toshiyuki; Sakamoto, Nobuo; Lu, He; Nishimura, Yoshikazu; Gao Lidi

    2009-01-01

    In order to investigate the behavior of rare earth elements (REEs), thorium (Th) and uranium (U) in soil environment, these elements in agricultural soils were partitioned and determined by a sequential extraction procedure into 6 fractions: water soluble (F (ws)), exchangeable (F (ec)), bound to carbonates (F (cb)), bound to organic matter (F (om)), bound to Fe-Mn oxides (F (fm)) and residual (F (rd)) fractions. Soil samples were collected from the agricultural field (paddy and upland field) and non-agricultural field in Sakata City in Yamagata Prefecture, and Nagaoka City in Niigata Prefecture on April 2005, October 2005 and April 2006. In addition, REEs, Th and U in crops grown on the soils and those in fertilizers used in the agricultural field were also determined. Consequently, the following matters have been mainly clarified. (1) REEs in soils mainly exists in the form of F (rd) fraction (i.e., silicate), although F (om) or F (fm) was relatively large proportion fraction (F (om) : 8-28% ; F (fm) : 6-20%) ; while U in soils may be present as the fraction bound to carbonate (15%) in addition to as F (rd) (60-70%). (2) The total concentrations of U in soil in agricultural field is remarkably larger (about 2 times) than that in non-agricultural field, although the concentrations of REEs and Th are not greatly varied regardless of soil utilizations (i.e., paddy field, upland field or no plow). (3) The value of pH(H 2 O)-pH(KCl) in soil of the upland field is smallest. Moreover, EC (electric conductivity) in soil of the upland field is much higher than that of the paddy field or of the non-agricultural field. (4) REE patten of the crops and fertilizers is generally similar to that of soils, although the order of the concentration of REEs is soils'>'fertilizers'>'crops'. (author)

  7. Separation and continuous determination of the light rare earth elements and thorium in Baotou Iron Ore by a micro-column

    International Nuclear Information System (INIS)

    Guo, G.; Luo, M.; Xu, J.; Wang, T.; Hua, R.; Sun, Y.

    2009-01-01

    A method for continuous determination of the light rare earth elements (LREEs) and thorium in Baotou Iron Ore was established. The light rare earths and thorium were adsorbed on a micro-column packed with HD-8 cation exchange resins. The light rare earth elements were eluted with 4 mol L -1 HCl-2 mol L -1 NH 4 Cl solution and determined with tribromo-arsenzao by a 721-E spectrophotometry at 630 nm; thorium was eluted with 5% potassium oxalate solution and determined with Arsenazo III by a 721-E spectrophotometry at 660 nm. The measured values by the proposed method were in close agreement with the certified values (Baotou main ore standard sample, Baotou ore R-715 standard sample and GSD-2 standard sample). The RSD of the light rare earths and thorium in Baotou Iron Ore were of < 1.70% and < 1.99%, respectively. (author)

  8. Rare earths, thorium, and other minor elements in sphene from some plutonic rocks in West-Central Alaska

    International Nuclear Information System (INIS)

    Staatz, M.H.; Conklin, N.M.; Brownfield, I.K.

    1977-01-01

    Sphene is an abundant accessory mineral in some abnormally radioactive plutonic rocks in west-central Alaska. Seven samples of sphene from four different areas in west-central Alaska contained from 20,350 to 39,180 parts per million total rare earths and 390 to 2000 ppM thorium. The lanthanide content in six of the seven sphenes is chiefly the light rare earths and is similar to that of crystal abundance; a seventh sphene from the Darby Mountains, however, contains above average amounts of the heavy rare earths. A comparison of the lanthanide distribution in sphene from several areas indicates that the structure of sphene will accommodate whatever lanthanides are available when the mineral crystallizes. The amount of thorium and rare earths in sphene is also affected by the presence of other accessory minerals. Sphene in rocks containing either allanite or zircon has a lower thorium content than in rocks that do not contain allanite or zircon. Sphene, because of its abundance, may contain the greater part of the rare earths and thorium in some of the plutonic rocks of west-central Alaska

  9. Rare earths and thorium

    International Nuclear Information System (INIS)

    Towner, R.R.

    1989-01-01

    In Australia, which is by far the Western world's largest producer of monazite, production is a by-product of the mineral-sands industry, mainly in the Midlands (Eneabba) and Southwest mineral-sands mining areas of Western Australia, and to a lesser extent on the east coast. Relatively small amounts of xenotime concentrate are a by-product of ilmenite mining in the Capel area of Western Australia. In 1987 a total of 12 813 t commercial-grade monazite was produced. At present monazite is not processed in Australia and all production is exported. In 1987 the Australian Bureau of Mineral Resources reassessed Australia's demonstrated resources of monazite upwards to 1.02 Mt, of which 237 800 t is regarded as economic at current prices for monazite, rutile, ilmenite and zircon. Production of rare-earth minerals in other countries is briefly reviewed. 4 tabs

  10. Recovery of thorium and rare earths by their peroxides precipitation from a residue produced in the thorium purification facility

    International Nuclear Information System (INIS)

    Freitas, Antonio Alves de

    2008-01-01

    As consequence of the operation of a Thorium purification facility, for pure Thorium Nitrate production, the IPEN (Instituto de Pesquisas Energeticas e Nucleares) has stored away a solid residue called RETOTER (REsiduo de TOrio e TErras Raras). The RETOTER is rich in Rare-Earth Elements and significant amount of Thorium-232 and minor amount of Uranium. Furthermore it contains several radionuclides from the natural decay series. Significant radioactivity contribution is generated by the Thorium descendent, mainly the Radium-228(T 1/2 =5.7y), known as meso thorium and Thorium-228(T 1/2 1.90y). An important thorium daughter is the Lead-208, a stable isotope present with an expressive quantity. After the enclosure of the operation of the Thorium purification facility, many researches have been developed for the establishment of methodologies for recovery of Thorium, Rare-Earth Elements and Lead-208 from the RETOTER. This work presents a method for RETOTER decontamination, separating and bordering upon some radioactive isotopes. The residue was digested with nitric acid and the Radium-228 was separated by the Barium Sulphate co-precipitation procedure. Finally, the Thorium was separated by the peroxide precipitation and the Rare-Earth Elements were also recovered by the Rare-Earth peroxide precipitation in the filtrate solution.(author)

  11. Separation, preconcentration and estimation of rare earth and trace elements by inductively coupled plasma-atomic emission spectrometry (ICP-AES) in thorium matrices

    International Nuclear Information System (INIS)

    Chakraborty, Prithwish; Kumar Vijay; Durani, Smeer; Satyanarayana, K.

    2007-01-01

    A simple, sensitive and efficient method is developed for the separation of Rare earth elements (REEs) La-Lu, and Y and some trace elements Cd, Co, Cr, Cu, Ni,V, Zn from thorium matrix and their subsequent estimations by ICP-AES. In thorium-rich geological samples, the estimation of REE's by ICP-AES suffers from the spectral interferences due to the presence of excess of Th. In the proposed method, thorium is separated from the matrix by the solvent extraction. To optimize the separation, of REEs and trace elements from Th matrix, synthetic mixture solutions was prepared containing Th, REEs and trace elements maintaining different acidic conditions (1M, 2M, 4M, 6M, 8M and 10M HNO 3 and 2M, 4M, 6M and 8M HCl) and each solution was subjected to solvent extraction. The solvent extraction was carried out using a mixture of di-2-ethylhexyl phosphoric acid (in 30 % Toluene) and 1- pentanol in the ratio of 5:1. The aqueous phase containing the required elements was evaporated to dryness and an acidity of 5% HCl is maintained in final volume. Solutions were analysed by ICP-AES and the quantitative recovery of REEs and trace elements were obtained at 6M HNO 3 acidity. The developed method was applied to the certified standard reference material: IGS-36 and the values obtained were comparable with the certified values. The method was also applied to the real time monazite sample and the recovery was quantitative. Corrections have been applied for the REEs inter-elemental interferences in ICP-AES. (author)

  12. Determination of rare earth elements, hafnium and cadmium in sintered pellets of mixed thorium and uranium oxides by neutron activation

    International Nuclear Information System (INIS)

    Cardoso, S.N.M.

    1987-01-01

    This work shows the development of a method for determination of the rare-earth elements (Eu, Sm, Dy and Gd), Hf and Cd contents in sinterized U and Th mixed oxides by neutron activation analysis. The sample is dissolved in nitric/fluoridric (0,1% HF) medium, to dryness and redissolved in 6N HCl solution. The Hf is extracted into organic phase (0,5 M TTA/benzene), irradiated and analysed through 181 Hf isotope energy peak. The aqueous phase is treated with NH 4 OH for the precipitation of hidroxides. Then, these are dissolved in 6N HNO 3 solution. The extraction of U and Th is made in two steps, one with TBP/CCl 4 and another with 0,5 M TTA/C 6 H 6 . Then the rare-earth elements and Cd are irradiated and determined by gamma spectrometry. (author) [pt

  13. Spectrographic determination of some rare earths in thorium compounds

    International Nuclear Information System (INIS)

    Brito, J. de.

    1977-01-01

    A method for spectrographic determination of Gd, Sm, Dy, Eu, Y, Yb, Tm and Lu in thorium compounds has been developed. Sensibilities of 0.01 μg rare earths/g Th02 were achieved. The rare earth elements were chromatographycally separated in a nitric acid-ether-cellulose system. The solvent mixture was prepared by dissolving 11% of concentrated nitric acid in ether. The method is based upon the sorption of the rare earths on activated cellulose, the elements being eluted together with 0.01 M HNO 3 . The retention of the 152 , 154 Eu used as tracer was 99,4%. The other elements showed recoveries varying from 95 to 99%. A direct carrier destillation procedure for the spectrochemical determination of the mentioned elements was used. Several concentrations of silver chloride were used to study the volatility behavior of the rare earths. 2%AgCl was added to the matrix as definite carrier, being lantanum selected as internal standard. The average coefficient of variation for this method was +- -+ 7%. The method has been appleid to the analysis of rare earths in thorium coumpounds prepared by Thorium Purification Pilot Plant at Atomic Energy Institute, Sao Paulo [pt

  14. SALICYLATE PROCESS FOR THORIUM SEPARATION FROM RARE EARTHS

    Science.gov (United States)

    Cowan, G.A.

    1959-08-25

    The separation of thorium from rare earths is accomplished by forming an aqueous solution of salts of thorium and rare earths and sufficient acetate buffer to provide a pH of between 2 and 5, adding an ammonium salicylate to the aqueous buffered solution, contacting the resultant solution with a substantially water-immiscible organic solvent mixture of an ether and an ester, and separating the solvent extract phase containing thorium salicylate from the aqueous phase containing the rare earths.

  15. Quantitative analysis of thorium in the presence of rare earth by X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Jesus, Camila S. de; Taam, Isabel; Vianna, Claudio A.

    2013-01-01

    The occurrence of Thorium in ores is normally associated to other elements such as Uranium and Cerium, as well as some Rare-Earths (RE). The separation of these elements by traditional analytic chemistry techniques is both time and reagent consuming, thus increasing the analysis cost. The hereby proposed method consists in the direct determination of Thorium in rare earths ores and compounds by X-ray fluorescence spectroscopy without any prior chemical separation from other matrix elements. This non-destructive technique is used to determine which elements are present in solid and liquid samples, as well as their concentrations. The studied matrix contains Lanthanum, Cerium, Praseodymium, Neodymium, Samarium, Gadolinium and Yttrium. This study evaluated the analytical lines of radiation emission for each rare earth contained in the matrix, comparing it to the Thorium main analytical line. The Thorium quantification was measured through the Th L line, where there is no influence or interference from the rare earths analytical lines. The studied samples are certified standards and the obtained results have been compared to Ethylenediaminetetraacetic acid (EDTA) titration results, an already well-established and widely trusted method. We also measured the matrix effect thus using complex rare earths liquor. This liquor contains also elements commonly found in monazites sands: phosphates, aluminum, iron. Obtained results state the efficiency of X-ray Fluorescence to determine Thorium in the presence of rare earths without any prior chemical separation. (author)

  16. Analysis of Uranium and Thorium in Waste Water from Rare Earth Research and Development by ICP Spectrometry

    International Nuclear Information System (INIS)

    Pichestapong, Pipat; Injareon, Uthaiwan

    2007-08-01

    Full text: Waste water from Rare Earth Research and Development Center (RRDC) was analyzed to determine uranium and thorium concentration using ICP spectrometry. RRDC processes monazite ore to separate uranium, thorium and rare earth elements from the ore. Water samples from the ditch surrounding the center and from the canal nearby were also analyzed. Matrix spike technique was applied in this analysis. It was found that the highest concentration of uranium and thorium in the waste water samples were 3028±11 and 439±7 ppb, respectively. The concentration of uranium and thorium in the waste water samples were higher than those in water samples from the ditch and canal

  17. Recovery of thorium and rare earths by their peroxides precipitation from a residue produced in the thorium purification facility; Recuperacao de torio e terras raras via peroxido do residuo originado na unidade de purificacao de torio

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Antonio Alves de

    2008-07-01

    As consequence of the operation of a Thorium purification facility, for pure Thorium Nitrate production, the IPEN (Instituto de Pesquisas Energeticas e Nucleares) has stored away a solid residue called RETOTER (REsiduo de TOrio e TErras Raras). The RETOTER is rich in Rare-Earth Elements and significant amount of Thorium-232 and minor amount of Uranium. Furthermore it contains several radionuclides from the natural decay series. Significant radioactivity contribution is generated by the Thorium descendent, mainly the Radium-228(T{sub 1/2}=5.7y), known as meso thorium and Thorium-228(T{sub 1/2} 1.90y). An important thorium daughter is the Lead-208, a stable isotope present with an expressive quantity. After the enclosure of the operation of the Thorium purification facility, many researches have been developed for the establishment of methodologies for recovery of Thorium, Rare-Earth Elements and Lead-208 from the RETOTER. This work presents a method for RETOTER decontamination, separating and bordering upon some radioactive isotopes. The residue was digested with nitric acid and the Radium-228 was separated by the Barium Sulphate co-precipitation procedure. Finally, the Thorium was separated by the peroxide precipitation and the Rare-Earth Elements were also recovered by the Rare-Earth peroxide precipitation in the filtrate solution.(author)

  18. Qualitative microanalysis of rare earths (ceric and yttric), of thorium and uranium in minerals

    International Nuclear Information System (INIS)

    Agrinier, H.

    1955-01-01

    We propose in this study to give a general method of attack of the niobio-titanates, niobio-tantalates, oxides, phosphates or silicates containing rare earths (ceric or yttric), uranium or thorium, and to put in evidence these different elements by microchemical reactions giving crystallization or the characteristic colorations. (M.B.) [fr

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

    International Nuclear Information System (INIS)

    Sabot, J.L.; Leveque, A.

    1983-01-01

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

  20. Evaluation of the concentrations of rare earth elements, uranium and thorium in the soil-plant system by Neutron Activation, k0 method

    International Nuclear Information System (INIS)

    Moura, Rodrigo Reis de; Menezes, Maria Ângela de Barros Correia; Marques, Douglas José

    2017-01-01

    The nuclear technique Neutron Activation Analysis (NAA) has improved results in a wide range of research fields, since it is a sensitive technique to determine very low concentrations at the trace level in several matrices.The k0 standardized is a NAA method that has been outstanding in the last decades because there is not the inconvenience of using standards for the elements of interest in the analysis. This increases the accuracy of the method and decreases the uncertainties in the obtained results. In this assessment, the NAA was applied to determine the rare earth elements (REEs), U and Th concentrations in plant and soil samples from a mining area. The data obtained by k0-method were used to calculate the amount of the concentrations of these elements present in the sample soil that were uptaken and fractionated in the studied plants by parameters commonly used, the Transfer Factor (TF) and Bio-concentration Coefficient (BC). The results showed that TF was slightly enriched to REEs (mainly La and Nd) and U and depleted to Th. The results presented to BC confirmed that among plant organs the root accumulated higher REEs concentration levels (root > stem > leaf) and on leaves were not detected Sm (Baccharis crispa), Eu (Baccharis crispa and Tibouchina granulosa) and Yb (Pteridium arachnoideum). Among species studied, Pteridium arachnoideum (fern) was the one that most uptaken and accumulated REEs, U and Th. (author)

  1. Evaluation of the concentrations of rare earth elements, uranium and thorium in the soil-plant system by Neutron Activation, k{sub 0} method

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Rodrigo Reis de, E-mail: rodrigoreismoura@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pós-Graduação em Ciências e Técnicas Nucleares; Menezes, Maria Ângela de Barros Correia, E-mail: menezes@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (SERTA/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Serviço de Técnicas Analíticas; Marques, Douglas José, E-mail: douglasjmarques81@yahoo.com.br [Universidade José do Rosário Vellano (Unifenas), Alfenas, MG (Brazil). Setor de Olericultura e Experimentação em Agricultura Orgânica

    2017-07-01

    The nuclear technique Neutron Activation Analysis (NAA) has improved results in a wide range of research fields, since it is a sensitive technique to determine very low concentrations at the trace level in several matrices.The k0 standardized is a NAA method that has been outstanding in the last decades because there is not the inconvenience of using standards for the elements of interest in the analysis. This increases the accuracy of the method and decreases the uncertainties in the obtained results. In this assessment, the NAA was applied to determine the rare earth elements (REEs), U and Th concentrations in plant and soil samples from a mining area. The data obtained by k0-method were used to calculate the amount of the concentrations of these elements present in the sample soil that were uptaken and fractionated in the studied plants by parameters commonly used, the Transfer Factor (TF) and Bio-concentration Coefficient (BC). The results showed that TF was slightly enriched to REEs (mainly La and Nd) and U and depleted to Th. The results presented to BC confirmed that among plant organs the root accumulated higher REEs concentration levels (root > stem > leaf) and on leaves were not detected Sm (Baccharis crispa), Eu (Baccharis crispa and Tibouchina granulosa) and Yb (Pteridium arachnoideum). Among species studied, Pteridium arachnoideum (fern) was the one that most uptaken and accumulated REEs, U and Th. (author)

  2. Determination of rare earth elements, thorium and uranium in seaweed samples on the coast in Niigata Prefecture by inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Nobuo [Graduate School of Science and Technology, Niigata University, Ikarashi 2-nocho 8050, Niigata (Japan); Kano, Naoki [Faculty of Engineering, Niigata University, Ikarashi 2-nocho 8050, Niigata (Japan)], E-mail: kano@eng.niigata-u.ac.jp; Imaizumi, Hiroshi [Faculty of Engineering, Niigata University, Ikarashi 2-nocho 8050, Niigata (Japan)

    2008-10-15

    The determination of rare earth elements (REEs), Th and U in seaweeds of various species and in ambient surface seawater were performed by inductively coupled plasma mass spectrometry. The seaweeds and the seawater samples were collected at 10 different coastal areas of Niigata Prefecture in Japan twice a year (spring and autumn) in 2004 and 2005. Results showed that concentration of REEs in seaweed species from Niigata Prefecture were about 10{sup 3} times higher than those in seawater, and the enrichment factors of REEs were larger in heavy REE than light REE. A significant concentration difference of REEs, Th and U was found among species even in the same phylum. Undaria pinnatifida had the highest concentration of U. Considering that U. pinnatifida has low concentrations of REEs among typical brown algae, different REEs and U uptake mechanisms are suggested. The concentration of REEs, Th and U did not vary remarkably between sampling points and/or seasons.

  3. Uses of extraction and ion exchange chromatography in the thorium and rare earths separation from industrial residue generated in thorium purification unity at IPEN. Application of rare earths as catalysts for generation of hydrogen

    International Nuclear Information System (INIS)

    Zini, Josiane

    2010-01-01

    In the 70's a pilot plant for studies of different concentrates processing obtained from the chemical processing of monazite was operated at IPEN / CNEN-SP, with a view to obtaining thorium of nuclear purity. This unity was operated on an industrial scale since 1985, generating around 25 metric tons of residue and was closed in 2002. This waste containing thorium and rare earths was named Retoter (Rejeito de Torio e Terras Raras, in portuguese) and stored in the IPEN Safeguards shed. This paper studies the treatment of the waste, aimed at environmental, radiological and technology. Were studied two cases for the chromatographic separation of thorium from rare earths. One of them was the chromatographic extraction, where the extracting agent tributyl phosphate was supported on polymeric resins Amberlite XAD16. The other method is studied for comparison purposes, since the material used in chromatographic extraction is unprecedented with regard to the separation of thorium, was the ion-exchange chromatography using DOWEX 1-X8 strong cationic resin. Was studied also the chromatographic process of extraction with the extracting agent DEHPA supported on Amberlite XAD16 for the fractionation in groups of rare earths elements. Thorium was separated with high purity for strategic purposes and rare earths recovered free from thorium, were tested as a catalyst for ethanol reforming to hydrogen obtaining which is used in fuel cells for power generation. (author)

  4. Global recovery process of thorium and rare earths in a nitrate medium

    International Nuclear Information System (INIS)

    Cailly, F.; Mottot, Y.

    1993-01-01

    The aqueous solution of thorium and rare earth nitrates, obtained by leaching the ore with nitric acid, is extracted by an organic phosphorous compound (phosphate, phosphonate, phosphinate or phosphine oxide) and a cationic extractant chosen among phosphoric acid di-esters. Extraction of thorium and rare earths is possible even in presence of phosphate ions in the aqueous solution. Thorium and rare earths are separated by liquid-liquid extraction of the organic phase

  5. Bioaccumulation of uranium and thorium from the solution containing both elements using various microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Tsuruta, T. [Department of Applied Chemistry, Tohwa University, 1-1-1 Chikushigaoka, Fukuoka 815-8510 (Japan)]. E-mail: ttsuruta@tohwa-u.ac.jp

    2006-02-09

    The effects of proton, thorium and uranium on the bioaccumulation of thorium and uranium from the solution (pH 3.5) containing uranium and thorium using Streptomyces levoris cells were examined. The amount of thorium accumulated using the cells decreased by the pre-contact between the cells and the solution (pH 3.5) containing no metals, whereas that of uranium was almost unaffected by the treatment. The amount of thorium was almost unaffected by the existence of uranium. On the other hand, the amount of uranium accumulated was strongly affected by the thorium, especially thorium addition after uranium accumulation. The decrease of uranium accumulated by the addition of thorium after the accumulation of uranium was higher than that from the solution containing both elements. Therefore, the contribution of uranium-thorium exchange reaction was higher than that of competition reaction. Accordingly, proton-uranium-thorium exchange reaction was occurred in the accumulation of thorium from the solution containing thorium and uranium. The gram-positive bacteria, such as Micrococcus luteus, Arthrobacter nicotianae, Bacillus subtilis and B. megaterium, has a much higher separation factor as thorium/uranium than that of actinomycetes. These gram-positive bacterial strains can be used for the accumulation of thorium from the solution containing uranium and thorium.

  6. Rare (Earth Elements [score

    Directory of Open Access Journals (Sweden)

    Camilo Méndez

    2014-12-01

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

  7. Creating a multi-national development platform: Thorium energy and rare earth value chain

    International Nuclear Information System (INIS)

    Kennedy, J.; Kutsch, J.

    2014-01-01

    Rare earths and thorium are linked at the mineralogical level. Changes in thorium regulations and liabilities resulted in the development of excessive market concentrations in the rare earth value chain. High value monazite rare earth resources, a by-product of heavy mineral sands mining, constituted a significant portion of global rare earth supply (and nearly 100% of heavy rare earths) until legislative changes, interpretation and enforcement regarding “source materials” in the early 1980s eliminated these materials from the supply chain.

  8. Bioleaching of rare earth elements from monazite sand.

    Science.gov (United States)

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

    2016-02-01

    Three fungal strains were found to be capable of bioleaching rare earth elements from monazite, a rare earth phosphate mineral, utilizing the monazite as a phosphate source and releasing rare earth cations into solution. These organisms include one known phosphate solubilizing fungus, Aspergillus niger ATCC 1015, as well as two newly isolated fungi: an Aspergillus terreus strain ML3-1 and a Paecilomyces spp. strain WE3-F. Although monazite also contains the radioactive element Thorium, bioleaching by these fungi preferentially solubilized rare earth elements over Thorium, leaving the Thorium in the solid residual. Adjustments in growth media composition improved bioleaching performance measured as rare earth release. Cell-free spent medium generated during growth of A. terreus strain ML3-1 and Paecilomyces spp. strain WE3-F in the presence of monazite leached rare earths to concentrations 1.7-3.8 times those of HCl solutions of comparable pH, indicating that compounds exogenously released by these organisms contribute substantially to leaching. Organic acids released by the organisms included acetic, citric, gluconic, itaconic, oxalic, and succinic acids. Abiotic leaching with laboratory prepared solutions of these acids was not as effective as bioleaching or leaching with cell-free spent medium at releasing rare earths from monazite, indicating that compounds other than the identified organic acids contribute to leaching performance. © 2015 Wiley Periodicals, Inc.

  9. Symbiotic energy demand and supply system based on collaboration between rare-earth and thorium utilization

    International Nuclear Information System (INIS)

    Kamei, Takashi

    2011-01-01

    Progressive economic growth as well as prodigious consumption of energy are expected among Asian countries. Nuclear power has myriad advantages, among them particularly being its status as a low carbon technology and therefore nuclear power would make a significant contribution to curtailing CO 2 emissions. However, the prospects for nuclear power are hindered by some unresolved problems: perceived adverse safety, environmental, and health effects; potential security risks stemming from proliferation; and unresolved challenges in long-term management of nuclear wastes. Thorium utilization as a nuclear fuel will serve as a cornerstone of circumventing such problems, because thorium produces less radioactive waste (i.e. less plutonium) and thus safety, which is of paramount concern, will be enhanced. The deployment of electric vehicles (EVs) as an alternative to supplant gasoline engine cars in the transportation network, will significantly contribute in the reduction of global CO 2 emissions. Rare-earth materials such as neodymium and dysprosium will be essential as a new material for electric automobiles. Thorium is often obtained as a by-product of rare-earth metals, but it is still not utilized as a nuclear fuel currently due to the lack of its own fissionable isotopes and as such, it cannot be employed in the production of nuclear weapons. Recent trends of nuclear disarmament and accumulation of plutonium from uranium fuel cycle can propel the deployment of thorium. The implementation capacity of thorium nuclear power is estimated to be about 392 GWe at 2050. The utilization of thorium will both help to provide clean energy and to supply rare-earth materials for clean automobiles. In order for us to effect the commercial deployment of thorium resources, establishment of an international framework to supply resources from developing countries as well as to supply technology from developed countries is indeed imperative. Herein, the author propose 'The Bank

  10. Separation of Rare Earths from Uranium and Thorium

    International Nuclear Information System (INIS)

    Krebs, Damien

    2014-01-01

    Greenland Minerals and Energy - Key Highlights – A unique world class mining project: 1. World-class, large scale development project: • Economically robust, proven technology, large-scale, long life production of rare earths concentrate and uranium; • Large JORC resource base to produce ~7kt HREO, 37kt LREO & 3Mlbs U 3 O 8 per annum over 30 year mine life; • Ideally located near international airport, existing towns and potential hydro-electric power source. 2. Very attractive commodity portfolio: • Heavy rare earths and uranium are both recognised as strategically important commodities for the future; • Rare earths market characterised by limited capacity and increasing demand (particularly Dy, Nd, Tb, Eu and Y). 3. Strong management and technical team: • Experienced management team with proven track record; • Well-respected and knowledgeable technical/project team in place with exceptional local expertise. 4. Highly advantageous ore-type, makes for simple cost-effective processing, highly scalable production: • High upgrade through beneficiation brings optionality to Kvanefjeld project; • Leaching can be done in Greenland, or owing to the high-grade concentrate, can be shipped to other locations; • Allows to single concentrator in Greenland, multiple refineries/partners globally. 5. Globally significant, long life, low cost, multi-commodity asset: • Company to become one of the largest producers of rare earths globally and a significant U 3 O 8 mine; • Potential to supply >20% of global critical (including heavy) rare earth element demand; • Company has low cost of production due to multiple by-product opportunities. 6. Low political risk: • Stable, low-risk operating environment with government looking to develop new industries and employment; • GME fully permitted to evaluate the project, exploration licence now includes radioactive elements; • Management and board have a solid working relationship with the government and are

  11. Status of thorium technology

    International Nuclear Information System (INIS)

    Garg, R.K.; Raghavan, R.V.; Karve, V.M.; Narayandas, G.R.

    1977-01-01

    Although a number of studies have been conducted in various countries to evolve reactor systems based on thorium fuel cycle, its use, so far, is limited to only a few reactors. However, for countries having large reserves of thorium, its utilization is of great significance for their nuclear power programmes. Reasonably assured world resources of thorium in the lower price range have been estimated at more than 500,000 tons of ThO 2 . While most of these resources are in placer deposits in various parts of the world, some vein deposits and uranium ores are other important sources of thorium. Monazite, the most important mineral of thorium, is found in the beach sand deposits along with other heavy minerals like ilmenite, rutile, zircon, and sillimanite etc. Mining of these deposits is usually carried out by suction dredging and separation of monazite from other minerals is effected by a combination of magnetic, electrostatic and gravity separation techniques. Chemical processing of monazite is carried out either by sulphuric acid or caustic treatment, followed by separation of the rare earths and thorium by partial precipitation or leaching. The thorium concentrate is further processed to obtain mantle grade thorium nitrate by chemical purification steps whereas solvent extraction using TBP is adopted for making nuclear-grade material. The purified thorium nitrate is converted to the oxide usually by precipitation as oxalate followed by calcination. The oxide is reduced directly with calcium or converted to the chloride or fluoride and then reduced by calcium or magnesium to obtain thorium metal. Various fuel designs based on the metal or its alloys, mixed oxides or carbides, and dispersed type fuel elements have been developed and accordingly, different fabrication techniques have been employed. Work on irradiation of thorium containing fuel elements and separation of U 233 is being carried out. This paper reviews the status of thorium technology in the world with

  12. Recovery of radiogenic lead-208 from a residue of thorium and rare earths obtained during the operation of a thorium purification pilot plant

    International Nuclear Information System (INIS)

    Seneda, Jose Antonio

    2006-01-01

    Brazil has a long tradition in thorium technology, from mineral dressing (monazite) to the nuclear grade thorium compounds. The estimate reserves are 1200,000. ton of ThO 2 . As a consequence from the work of thorium purification pilot plant at Instituto de Pesquisas Energeticas e Nucleares-CNEN/IPEN-SP, about 25 ton of a sludge containing thorium and rare earths was accumulated. It comes as a raffinate and washing solutions from thorium solvent extraction. This sludge, a crude hydroxide named RETOTER contains thorium, rare earths and minor impurities including the radiogenic lead-208, with abundance 88.34 %. This work discusses the results of the studies and main parameters for its recovery by anionic ion exchange technique in the hydrochloric system. The isotope abundance of this lead was analyzed by high resolution mass spectrometer (ICPMS) and thermoionic mass spectrometer (TIMS) and the data was used to calculate the thermal neutron capture cross section. The value of σγ 0 = 14.6±0.7 mb was found, quite different from the σγ 0 = 174.2 ± 7.0 mb measure cross section for the natural lead. Preliminary study for the thorium and rare earths separation and recovery was discussed as well. (author)

  13. Recovery of radiogenic lead-208 from a residue of thorium and rare earths obtained during the operation of a thorium nitrate purification pilot plant

    International Nuclear Information System (INIS)

    Seneda, Jose Antonio

    2006-01-01

    Brazil has a long tradition in thorium technology, from mineral dressing (monazite) to the nuclear grade thorium compounds. The estimate reserves are 1200,000. ton of ThO 2 . As a consequence from the work of thorium purification pilot plant at Instituto de Pesquisas Energeticas e Nucleares-CNEN/SP, about 25 ton of a sludge containing thorium and rare earths was accumulated. It comes as a raffinate and washing solutions from thorium solvent extraction. This sludge, a crude hydroxide named RETOTER contains thorium, rare earths and minor impurities including the radiogenic lead-208, with abundance 88.34 %. This work discusses the results of the studies and main parameters for its recovery by anionic ion exchange technique in the hydrochloric system. The isotope abundance of this lead was analyzed by high resolution mass spectrometer (ICPMS) and thermoionic mass spectrometer (TIMS) and the data was used to calculate the thermal neutron capture cross section. The value of s ? o = 14.6 +/- 0.7 mb was found, quite different from the s ? o = 174.2 +/- 7.0 mb measure cross section for the natural lead. Preliminary study for the thorium and rare earths separation and recovery was discussed as well. (author)

  14. Geology and description of thorium and rare-earth deposits in the southern Bear Lodge Mountains, northeastern Wyoming

    Science.gov (United States)

    Staatz, M.H.

    1983-01-01

    The Bear Lodge Mountains are a small northerly trending range approximately 16 km northwest of the Black Hills in the northeast corner of Wyoming. Thorium and rare-earth deposits occur over an area of 16 km 2 in the southern part of these mountains. These deposits occur in the core of the Bear Lodge dome in a large multiple intrusive body made up principally of trachyte and phonolite. Two types of deposits are recognized: disseminated deposits and veins. The disseminated deposits are made up of altered igneous rocks cut by numerous crisscrossing veinlets. The disseminated deposits contain thorium and rare-earth minerals in a matrix consisting principally of potassium feldspar, quartz, and iron and manganese oxides. Total rare-earth content of these deposits is about 27 times that of the thorium content. The general size and shape of the disseminated deposits were outlined by making a radiometric map using a scintillation counter of the entire Bear Lodge core, an area of approximately 30 km 2 . The most favorable part of this area, which was outlined by the 40 countJs (count-per-second) isograd on the radiometric map, was sampled in detail. A total of 341 samples were taken over an area of 10.6 km 2 and analyzed for as many as 60 elements. Rare earths and thorium are the principal commodities of interest in these deposits. Total rare-earth content of these samples ranged from 47 to 27,145 ppm (parts per million), and the thorium content from 9.3 to 990 ppm. The amount of total rare earths of individual samples shows little correlation with that of thorium. Contour maps were constructed using the analytical data for total rare earths, thorium, uranium, and potassium. The total rare-earth and thorium maps can be used to define the size of the deposits based on what cut-off grade may be needed during mining. The size is large as the 2,000 ppm total rare-earth isograd encloses several areas that total 3.22 km 2 in size, and the 200 ppm thorium isograd encloses several

  15. Thorium and uranium separation from Rare Earth complex minerals in Turkey

    International Nuclear Information System (INIS)

    Uzmen, R.

    2014-01-01

    Conclusion: • Thorium and uranium separation from a REEs solution is possible in by using simple traditional methods. • Main advantage of this method is to separate with high recovery yield uraniumand almost completely thorium which is an undesirable element due to its radioactive property in the different REEs group or individual REE. • Separation of thorium before any other step of REE’s group or individual element separation is crucial. • By using this flowsheet it would be possible to obtain uranium and other valuable elements (Zr, Ti, etc.) as coproducts of REEs. • Another important point, during REEs production, it is avoided to accumalate U and Th contaminated process wastes. • Thus, in the contrary, radioactive elements are refined and contained for safe storage.

  16. Thorium: Issues and prospects in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    AL-Areqi, Wadeeah M.; Majid, Amran Ab.; Sarmani, Sukiman; Bahri, Che Nor Aniza Che Zainul [Nuclear Science Programme, School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Malaysia. walareqi@yahoo.com (Malaysia)

    2015-04-29

    In Malaysia, thorium exists in minerals and rare earth elements production residue. The average range of thorium content in Malaysian monazite and xenotime minerals was found about 70,000 and 15,000 ppm respectively. About 2,636 tonnes of Malaysian monazite was produced for a period of 5 years (2006-2010) and based on the above data, it can be estimated that Malaysian monazite contains about 184.5 tonnes of thorium. Although thorium can become a major radiological problem to our environment, but with the significant deposit of thorium in Malaysian monazite, it has a prospect as a future alternative fuel in nuclear technology. This paper will discuss the thorium issues in Malaysia especially its long term radiological risks to public health and environment at storage and disposal stages, the prospect of exploring and producing high purity thorium from our rare earth elements minerals for future thorium based reactor. This paper also highlights the holistic approach in thorium recovery from Malaysian rare earth element production residue to reduce its radioactivity and extraction of thorium and rare earth elements from the minerals with minimum radiological impact to health and environment.

  17. Stepwise hydrochloric acid extraction of monazite hydroxides for the recovery of cerium lean rare earths, cerium, uranium and thorium

    International Nuclear Information System (INIS)

    Swaminathan, T.V.; Nair, V.R.; John, C.V.

    1988-01-01

    Monazite sand is normally processed by the caustic soda route to produce mixed rare earth chloride, thorium hydroxide and trisodium phosphate. Bulk of the mixed rare earth chloride is used for the preparation of FC catalysts. Recently some of the catalyst producers have shown preference to cerium depleted (lanthanum enriched) rare earth chloride rather than the natural rare earth chloride obtained from monazite. Therefore, a process for producing cerium depleted rare earth chloride, cerium, thorium and uranium from rare earth + thorium hydroxide obtained by treating monazite, based on stepwise hydrochloric acid extraction, was developed in the authors laboratory. The process involves drying of the mixed rare earth-thorium hydroxide cake obtained by monazite-caustic soda process followed by stepwise extraction of the dried cake with hydrochloric acid under specified conditions

  18. Neutron activation analysis in geological samples containing rare earths, uranium and thorium

    International Nuclear Information System (INIS)

    Vasconcellos, M.B.A.; Figueiredo, A.M.G.; Berretta, J.R.; Soares, J.C.A.C.R.; Fratin, L.; Goncales, O.L.; Botelho, S.

    1990-01-01

    The neutron activation analysis method was used for determination of rare earths, uranium, thorium and other tracks in geological samples, under the geological standard JB-1 (Geological Survey of Japan) and S-8 and S-13 (IAEA). (L.C.J.A.)

  19. Creating a Multi-National Platform: Thorium Energy & Rare Earth Value Chain. Assessing Rare Earths and Global Imbalance: Chinese Industrial Policy vs. Adverse NRC/IAEA Policy = Market Failure Will Thorium Energy Systems be next?

    International Nuclear Information System (INIS)

    Kennedy, James; Kutsch, John

    2014-01-01

    Full Spectrum Rare Earth Production & fully integrated Value Chain: Developing low value rare earth deposits with high direct cost is not economically viable. High value, low-cost, byproduct resources are abundant and available. Thorium bearing Rare Earth Phosphates could meet 50% or more of global demand if the Thorium issue could be resolved. There is no need to develop any new RE mining operations – just fix the Thorium Problem. Fully Integrated Value Chain Capabilities are Paramount: All efforts must focus on developing a fully integrated value chain.

  20. Rare-earth elements

    Science.gov (United States)

    Van Gosen, Bradley S.; Verplanck, Philip L.; Seal, Robert R.; Long, Keith R.; Gambogi, Joseph; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    The rare-earth elements (REEs) are 15 elements that range in atomic number from 57 (lanthanum) to 71 (lutetium); they are commonly referred to as the “lanthanides.” Yttrium (atomic number 39) is also commonly regarded as an REE because it shares chemical and physical similarities and has affinities with the lanthanides. Although REEs are not rare in terms of average crustal abundance, the concentrated deposits of REEs are limited in number.Because of their unusual physical and chemical properties, the REEs have diverse defense, energy, industrial, and military technology applications. The glass industry is the leading consumer of REE raw materials, which are used for glass polishing and as additives that provide color and special optical properties to the glass. Lanthanum-based catalysts are used in petroleum refining, and cerium-based catalysts are used in automotive catalytic converters. The use of REEs in magnets is a rapidly increasing application. Neodymium-iron-boron magnets, which are the strongest known type of magnets, are used when space and weight are restrictions. Nickel-metal hydride batteries use anodes made of a lanthanum-based alloys.China, which has led the world production of REEs for decades, accounted for more than 90 percent of global production and supply, on average, during the past decade. Citing a need to retain its limited REE resources to meet domestic requirements as well as concerns about the environmental effects of mining, China began placing restrictions on the supply of REEs in 2010 through the imposition of quotas, licenses, and taxes. As a result, the global rare-earth industry has increased its stockpiling of REEs; explored for deposits outside of China; and promoted new efforts to conserve, recycle, and substitute for REEs. New mine production began at Mount Weld in Western Australia, and numerous other exploration and development projects noted in this chapter are ongoing throughout the world.The REE-bearing minerals are

  1. Rare-earth elements

    International Nuclear Information System (INIS)

    Leveque, A.; Maestro, P.

    1993-01-01

    Production process of rare earths come from hydro-metallurgy treatments including following successive steps from enrichment ores: ore etching by humid way, from obtained solutions separations and purifications using selective precipitation engineering (rare earths case with an oxidation degree different from III), sometimes exchange techniques of ion on resin but principally extraction techniques by solvent; obtaining final products (oxides, salts) or metals elaboration by electrolytic melt salts process at high temperature. About applications, specificity of rare earths is in their particular electronic structure which induces chemical, structural, and physical properties seen as unrivalled ones. These properties are used in industrial applications which are diversified and sophisticated as metallurgy, catalysis, glass, optics, ceramics, luminescence, magnetism, electronics... 44 refs., 6 figs., 7 tabs

  2. Rare-earth and thorium in soil and manioc: determination using neutron activation analysis; Terras-raras e torio em solo e mandioca: determinacao por ativacao neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Lucilene Guerra e [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Faculdade de Farmacia; Menezes, Maria Angela de B.C.; Palmieri, Helena E.L. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil). Servico de Reator e Irradiacoes]. E-mail: menezes@cdtn.br; Nalini Junior, Herminio A. [Ouro Preto Univ., MG (Brazil). Dept. de Geologia; Jacimivic, Radojko [Instituto Josef Stefan, Liubliana (Slovenia). Dept. de Ciencias Ambientais

    2005-07-01

    This paper reports the elements rare-earth and Thorium determined in soil and manioc during an assessment carried out to evaluate the elemental concentration in several matrixes connected with the chain food. One site studied is in the Iron Quadrangle, Minas Gerais, Brazil, that presented mineral exploration activity in the past. Another site is without any mining activity and it is outside the Quadrangle. The objective was to evaluate the influence of a mining activity on the elemental concentration in the soil and manioc is grown around the mining area. The elemental determination was achieved by applying the k{sub 0}-instrumental Neutron Activation. (author)

  3. Behavior of radioactive elements (uranium and thorium) in Bayer process

    International Nuclear Information System (INIS)

    Sato, C.; Kazama, S.; Sakamoto, A.; Hirayanagi, K.

    1986-01-01

    It is essential that alumina used for manufacturing electronic devices should contain an extremely low level of alpha-radiation. The principal source of alpha-radiation in alumina is uranium, a minor source being thorium. Uranium in bauxite dissolves into the liquor in the digestion process and is fixed to the red mud as the desilication reaction progresses. A part of uranium remaining in the liquor precipitates together with aluminum hydroxide in the precipitation process. The uranium content of aluminum hydroxide becomes lower as the precipitation velocity per unit surface area of the seed becomes slower. Organic matters in the Bayer liquor has an extremely significant impact on the uranium content of aluminum hydroxide. Aluminum hydroxide free of uranium is obtainable from the liquor that does not contain organic matters

  4. Scarcity of rare earth elements

    NARCIS (Netherlands)

    de Boer, M.A.; Lammertsma, K.

    2013-01-01

    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

  5. Scarcity of rare earth elements.

    Science.gov (United States)

    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. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Distribution of rare earths, thorium and uranium in bryophytes and soils in Tripui Ecological Station, Minas Gerais, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Palmieri, Helena E.L. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)], E-mail: help@cdtn.br; Nalini Junior, Herminio A. [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Dept. de Geologia], E-mail: nalini@degeo.ufop.br; Friese, Kurt [Helmholtz Centre for Environmental Research- UFZ, Magdeburg (Germany). Dept. of Lake Research], E-mail: kurt.friese@ufz.de

    2007-07-01

    The concentrations of rare earth elements (REEs), thorium and uranium were determined in liverworts (Noteroclada confluens (Tayl.) and Dumortirea hirsute (Sw.) Nees), in mosses (Leucobryum martianum (Hornsh.) Hampe, Vesicularia vesicularis (Schwaegr.) Broth., Pyrrhobruym spiniforme (Hedw.) Mitt. and Sematophyllum subsimplex (Hedw.) Mitt.) and in the soil upon which they were growing. The samples were collected on the margins of the main streams of the Tripui Ecological Station, located in the valley of the Tripui stream near the town of Ouro Preto, Minas Gerais State, Brazil. For decades, this Station has been the object of interest of many studies due to its historical, ecological and environmental importance. Analyses in bryophytes (mosses and liverworts) were determined by inductively coupled plasma mass spectrometry (ICP-MS) and in the soil samples by using neutron activation analysis (NAA), specifically the k{sub 0}-standardization method and the energy dispersive spectrometry technique (EDS). Lanthanum (La), cerium (Ce) and neodymium (Nd) were present in higher concentrations in soils and bryophytes than other REEs. It was observed that in all the collected bryophytes species the elements Th, U, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb were transferred from the soil water to these plants. These bryophytes presented different capacities of accumulating these elements with the liverworts (Noteroclada confluens and Dumortirea hirsute) and the moss Leucobryum martianum showing a more efficient accumulation capacity than the other bryophyte species. (author)

  7. Optimization of thorium-uranium content in a 54-element fuel bundle for use in a CANDU-SCWR

    Energy Technology Data Exchange (ETDEWEB)

    Hummel, D.W.; Novog, D.R. [McMaster Univ., Dept. of Engineering Physics, Hamilton, Ontario (Canada)

    2011-07-01

    A new 54-element fuel bundle design has been proposed for use in a pressure-tube supercritical water-cooled reactor, a pre-conceptual evolution of existing CANDU reactors. Pursuant to the goals of the Generation IV International Forum regarding advancement in nuclear fuel cycles, optimization of the thorium and uranium content in each ring of fuel elements has been studied with the objectives of maximizing the achievable fuel utilization (burnup) and total thorium content within the bundle, while simultaneously minimizing the linear element ratings and coolant void reactivity. The bundle was modeled within a reactor lattice cell using WIMS-AECL, and the uranium and thorium content in each ring of fuel elements was optimized using a weighted merit function of the aforementioned criteria and a metaheuristic search algorithm. (author)

  8. Elements for evaluation of the potential of the thorium cycle in Argentina

    International Nuclear Information System (INIS)

    Corcuera, R.M.

    1987-01-01

    A comprehensive review of the most important elements to be taken into account for the evaluation and, eventually, the implementation of the introduction of thorium cycle strategies in argentinian heavy-water type power plants, and also of the associated development of the external fuel cycle, is presented. Particularly, the up-dated situations summarized here cover resources and prices of natural uranium and thorium, development of the various stages of the external fuel cycle, description of the most important strategies and their capabilities for the best use of mineral resources and, finally, the economic implications and the global comparison of those strategies. Various data and parameter values are added to those given in AECL's external reports. Some appendices are devoted to the definitions of a 'global fuel-cycle conversion factor' and to the analysis of the effective use of mineral resources, taking into account fissile and fertile material losses in the external fuel cycle., for the different cases of fuel conversion and breeding. (Author) [es

  9. Chemical analysis of rare earth elements

    International Nuclear Information System (INIS)

    Tsukahara, Ryoichi; Sakoh, Takefumi; Nagai, Iwao

    1994-01-01

    Recently attention has been paid to ICP-AES or ICP-MS, and the reports on the analysis of rare earth elements by utilizing these methods continue to increase. These reports have become to take about 30% of the reports on rare earth analysis, and this is because these methods are highly sensitive to rare earth elements, and also these methods have spread widely. In ICP-AES and ICP-MS, mostly solution samples are measured, therefore, solids must be made into solution. At the time of quantitatively determining the rare earth elements of low concentration, separation and concentration are necessary. Referring to the literatures reported partially in 1990 and from 1991 to 1993, the progress of ICP-AES and ICP-MS is reported. Rare earth oxides and the alloys containing rare earth elements are easily decomposed with acids, but the decomposition of rocks is difficult, and its method is discussed. The separation of the rare earth elements from others in geochemical samples, cation exchange process is frequently utilized. Also solvent extraction process has been studied. For the separation of rare earth elements mutually, chromatography is used. The spectral interference in spectral analysis was studied. The comparison of these methods with other methods is reported. (K.I)

  10. Thorium and health: state of the art

    International Nuclear Information System (INIS)

    Leiterer, A.; Berard, Ph.; Menetrier, F.

    2010-01-01

    This report reviews data available in the literature on the subject: 'thorium and health'. Thorium is a natural radioactive element of the actinide series. It is widely distributed in the earth's crust and 99% is found as isotope thorium-232. Its various uses are explained by its chemical, physical, and nuclear properties. As a potential nuclear fuel, thorium is still in demonstration in pilot scale reactors. But thorium has already multiple and sometimes unknown industrial uses. Some mass market products are concerned like light bulb. This raises the issue of wastes, and of exposures of workers and public. Environmental exposure via food and drink of the general population is low, where as workers can be exposed to significant doses, especially during ore extraction. Data on bio-monitoring of workers and biokinetic of thorium, in particular those provided by ICRP, are gathered here. Studies on health effects and toxicity of thorium are scarce and mostly old, except outcomes of its previous medical use. Studies on other forms of thorium should be undertaken to provide substantial data on its toxicity. Concerning treatment, Ca-DTPA is the recommended drug even if its efficacy is moderate. LiHOPO molecule shows interesting results in animals, and further research on chelating agents is needed. (authors)

  11. A newly developed accelerator to convert thorium to uranium-233

    International Nuclear Information System (INIS)

    Kamei, T.

    2014-01-01

    For constructing a sustainable society, low-carbon energy sources and low-carbon automobiles are required. In addition to the use of nuclear power, renewable energy such as wind-mills and solar power are used as low-carbon energy sources. Electric vehicle (EV) and hybrid vehicle (HV) are expected to be used as low-carbon automobiles. Essential raw material in order to fabricate these machineries is rare-earth elements (REE). In these few years, rare-earth supply has been unstable due to China’s monopoly in its production. China’s monopoly of rare-earth production was caused by loss of market competitiveness of other countries that needed to spend cost for taking care of “thorium” which occurred as by-product of rare-earth refining. Thorium can be used as nuclear fuel but thorium is merely fertile. Therefore, additional supply of fissile material is necessary to use thorium. As a result, there are no countries that separate and store thorium as valuable except India. The authors have studied (1) molten-salt reactor (MSR) as a utilizing technology of thorium, (2) implementation capacity of thorium MSR supported by a supply of plutonium from spent uranium fuel and (3) international framework to protect environment from thorium which occurs as by-product of rare-earth refining. Available implementation capacity of thorium MSR by using all plutonium based on the prediction of IEA’s uranium fuel cycle is only 392 GW at 2050. This capacity of thorium MSR requires 76 thousand tonnes of thorium but total amount of thorium occurring as by-product of rare-earth reaches to 444 thousand tonnes. If there is no use of thorium, it could be abandoned to environment illegally. The authors are considering a new framework to protect environment by giving an incentive of storing thorium by adding value to these excess thorium. A newly developed accelerator neutron source is a method to add value to thorium. Spallation reaction has been known as neutron source which uses high

  12. Titration of thorium and rare earths with ethylenediaminetetraacetic acid using semimethylthymol blue by visual end-point indication

    International Nuclear Information System (INIS)

    Hafez, M.A.H.; Kenawy, I.M.M.; Ramadan, M.A.M.

    1994-01-01

    The precision and accuracy attainable in direct complexometric titrations of Thsup(4+) consecutively with either lighter (La 3+ , Nd 3+ , Sm 3+ , Eu 3+ or Gd 3+ ) or heavier lanthanides (Dy 3+ ) in different proportions using Semimethylthymol Blue (SMTB) as a metallochromic indicator and disodium dihydrogen ethylenediaminetetraacetate were studied. Thorium (IV) was titrated at pH 2, the Ph was adjusted to 5.5-6.0 by adding hexamethylenetetramine (hexamine) buffer and acetylacetone-acetone solution and La 3+ (or Nd 3+ , Sm 3+ , Eu 3+ , Gd 3+ or Dy 3+ ) was then titrated. A comparison of the indicators SMTB and Methylthymol Blue (MTB) for successive titrations of Th 4+ and any of the rare earth ions was carried out. The proposed titration method was applied successfully to some naturally occurring ores and minerals containing thorium and some lanthanides and the results were satisfactory. (Author)

  13. Rare earth elements in nuclear medicine

    Directory of Open Access Journals (Sweden)

    Kodina G.E.

    2014-12-01

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

  14. Rare earth elements and strategic mineral policy

    NARCIS (Netherlands)

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

    2010-01-01

    Newspapers report almost daily on international tensions around ‘strategic’ or ‘critical’ minerals such as rare earth elements. The temporary freeze of rare earth exports from China to Japan in late 2010 in retaliation of the capture of a Chinese captain is but one example of the strategic use of

  15. Effect of Thorium on Growth and Uptake of Some Elements by Maize Plant

    International Nuclear Information System (INIS)

    Al-Shobaki, M.E.E.

    2012-01-01

    A pot experiment (sand culture) was carried out to investigate the effect of thorium on maize dry matter yield, contents and uptake of N,P ,K, Na and Fe and thorium accumulation in maize plant.The pots were contaminated by thorium as Thorium Nitrate(Th (NO 3 ) 4 ,H 2 O)at concentrations 0,5,10,11,12,13,14,15 and 50 ppm. Pots irrigated by 1/10 Hogland solution for 15 days, increased tol/4 Hogland solution after that.The results show that the dry matter (shoot, root and whole plant)decreased with increasing thorium concentration in soil up to 12 ppm and slightly increased with increasing Th to 13 ppm . The Nitrogen content and its uptake decreased with increasing thorium concentration in media growth up to 11 ppm .They were slightly increased at Th concentration between 11-14 ppm in maize shoot and root. The shoots always contained N-content and uptake more than that found in roots . P- uptake decreased in both shoots and roots with increasing in thorium concentration in media growth.

  16. Thorium and its future importance for nuclear energy generation

    International Nuclear Information System (INIS)

    Lainetti, Paulo E.O.

    2015-01-01

    Thorium was discovered in 1828 by the Swedish chemist Jons J. Berzelius. Despite some advantages over uranium for use in nuclear reactors, its main use, in the almost two centuries since its discovery, the use of thorium was restricted to use for gas mantles, especially in the early twentieth century. In the beginning of the Nuclear Era, many countries had interested on thorium, particularly during the 1950-1970 period. There are about 435 nuclear reactors in the world nowadays. They need more than 65.000 tons of uranium yearly. The future world energy needs will increase and, even if we assumed a conservative contribution of nuclear generation, it will be occur a significant increasing in the uranium prices, taking into account that uranium, as used in the present thermal reactors, is a finite resource. Thorium is nearly three times more abundant than uranium in the Earth's crust. Despite thorium is not a fissile material, 232 Th can be converted to 233 U (fissile) more efficiently than 238 U to 239 Pu. Besides this, since it is possible to convert thorium waste into nonradioactive elements, thorium is an environment-friendly alternative energy source. Thorium fuel cycle is also inherently resistant to proliferation. Some papers evaluate the thorium resources in Brazil over 1.200.000 metric t. Then, the thorium alternative must be seriously considered in Brazil for strategic reasons. In this paper a brief history of thorium is presented, besides a review of the world thorium utilization and a discussion about advantages and restrictions of thorium use. (author)

  17. Uranium, thorium and trace elements in geologic occurrences as analogues of nuclear waste repository conditions

    International Nuclear Information System (INIS)

    Wollenberg, H.A.; Brookins, D.G.; Cohen, L.H.; Flexser, S.; Abashian, M.; Murphy, M.; Williams, A.E.

    1984-01-01

    Contact zones between intrusive rocks and tuff, basalt, salt and granitic rock were investigated as possible analogues of nuclear waste repository conditions. Results of detailed studies of contacts between quartz monzonite of Laramide age, intrusive into Precambrian gneiss, and a Tertiary monzonite-tuff contact zone indicate that uranium, thorium and other trace elements have not migrated significantly from the more radioactive instrusives into the country rock. Similar observations resulted from preliminary investigations of a rhyodacite dike cutting basalt of the Columbia River plateau and a kimberlitic dike cutting bedded salt of the Salina basin. This lack of radionuclide migration occurred in hydrologic and thermal conditions comparable to, or more severe than those expected in nuclear waste repository environments and over time periods of the order of concern for waste repositories. Attention is now directed to investigation of active hydrothermal systems in candidate repository rock types, and in this regard a preliminary set of samples has been obtained from a core hole intersecting basalt underlying the Newberry caldera, Oregon, where temperatures presently range from 100 to 265 0 C. Results of mineralogical and geochemical investigations of this core should indicate the alteration mineralogy and behavior of radioelements in conditions analogous to those in the near field of a repository in basalt

  18. Non-parametric study on the optimization of thorium content in a 54-element fuel bundle for use in a CANDU-SCWR

    International Nuclear Information System (INIS)

    Hummel, D.W.; Novog, D.R.

    2011-01-01

    A new 54-element fuel bundle design has been proposed for use in a Supercritical Water-Cooled Reactor, a conceptual evolution of existing CANDU reactors. Pursuant to the goals of the Generation IV International Forum, specifically regarding advancement in fuel cycles, the feasibility of optimizing the thorium content within each ring of fuel elements has been studied. 864 unique permutations of thorium and uranium content were modeled with WIMS-AECL, and the results were analyzed using non-parametric statistical methods. Key findings include that discharge burnup and coolant void reactivity are inversely related to the total thorium content in the bundle, and that the maximum linear rating and form factor are inversely related to the thorium content in the outermost ring of fuel elements. (author)

  19. The safety of operations in the Dragon fuel element production building during the manufacture of thorium fuel for the first charge of the Dragon Reactor experiment

    International Nuclear Information System (INIS)

    Beutler, H.; Gardham, B.; Holliday, J.

    1965-04-01

    The first charge of fuel and fuel elements for the Dragon Reactor has been completed without significant difficulty. This report covers the safety of operations during the production of the 10 thorium elements together with the final 2 driver elements needed to complete the 37 element charge. (author)

  20. Chromatographic behavior of carbonate complexes of lanthanides and of thorium in alumina

    International Nuclear Information System (INIS)

    Tomida, E.K.

    1977-01-01

    The chromatographic behavior of some rare earth elements and thorium on alumina is studied in order to evaluate the possibility of separation from concentration of trace rare earths from high-purity thorium compounds. The effect of some factors on complex thorium carbonate formation and the extent of thorium solubility in sodium and potassium carbonate solutions investigated. The sorption of rare earth elements and thoriuum on alumina from alkali carbonate solution is observed, despite the reports that alumina acts as a cation exchanger in alkali media and that thorium and rare earths form stable anionic carbonate complexes. The formation of these elements between alumina and potassium carbonate solutions is studied as a function of pH, carbonate concentration and metal ion concentration. Also the elution of rare earths from alumina is studied and the best results are obtained with mineral acids and EDTA plus alkali carbonate solutions. The effect of some parameters as column aging, mixed solvents, column treatment with organic solvents, temperature, aluant concentration is investigated. Attempting to understand this sorption mechanism, some experiments with strongly basic anion exchanger and cation exchangers of strongly acid and weakly acid type are accomplished. It is observed that there are significant differences, in some conditions, between the behavior of rare earths and of thorium, pointing our the possibility of separation of one lanthanide from others and of these from thorium [pt

  1. Uranium, Thorium and some other trace elements in phosphorites from different provenances

    Science.gov (United States)

    Bech, J.; Reverter, F.; Tume, P.; Roca, N.; Suarez, E.; Sepúlveda, G.; Sokolovska, M.

    2012-04-01

    Data on the trace element composition of phosphorites is scarce. Some of them may be harmful at certain concentrations. Special concern is given to the radionuclides U and Th and some other heavy metals such as: Co, Cr, Cu, Ni and V. Phosphorites of different origins can vary significantly in the trace element concentrations. 37 samples of phosphorites from 16 deposits were analyzed for Uranium, Thorium and five potential toxic elements (Co, Cr, Cu, Ni and V) as well as 26 samples of data gathered from the literature. In total 63 samples of phosphorites from 20 deposits of 19 countries were studied: Algeria, Australia, Brazil, Burkina Faso, Chile, Colombia, Egypt, India, Israel, Mongolia, Morocco, New Zealand, Peru, Senegal, Syria, Togo, Tunisia, USA and Venezuela. Aqua regia extracts were used to estimate the "pseudototal" values, following standard procedures (ISO 11466, 2002) and measured by ICP-MS. The median concentrations (mgkg-1) obtained were: U 53 (range 0.20-177), Th 4.05 (range 1-49), Co 4 (range 0.5-159), Cr 100 (range 15-1000), Cu 20 (range 5-213), Ni 21 (range 3-850) and V 70.05 (range 20-591). As 120 mgkg-1 of U concentration of phosphorites is the value considered to be useful as a source of nuclear fuel, we now indicate the deposits with values higher than 120 mgkg-1: Khouribga KIISB (Morocco) 121, Khouribga KIISL (Morocco) 123, Champ mines (Idaho, USA) 131, Noralyn (Central Florida, USA) 138, Bone Valley (Florida, USA) 140, Boucraa BGB (Morocco) 141, Boucraa BGC (Morocco) 152, Negev (Israel) 172 and Chatam Rise (New Zealand) 177. The highest Th concentration found was 49 mgkg-1 at Bijawar Group (India). Uranium shows significant positive correlations with V (r = 0.41) and Cr (r = 0.30), and significant negative correlations with Co (r= -0.47). Other positive correlations are Cr with Cu (r=0.58), Cr with V (r=0.52) and Cr with Ni (r=0.51). Cu correlates positively with Ni (r=0.84) and with V (r=0.63). Ni correlates positively with V (r=0.72).

  2. A deposit model for carbonatite and peralkaline intrusion-related rare earth element deposits: Chapter J in Mineral deposit models for resource assessment

    Science.gov (United States)

    Verplanck, Philip L.; Van Gosen, Bradley S.; Seal, Robert R.; McCafferty, Anne E.

    2014-01-01

    Carbonatite and alkaline intrusive complexes, as well as their weathering products, are the primary sources of rare earth elements. A wide variety of other commodities have been exploited from carbonatites and alkaline igneous rocks including niobium, phosphate, titanium, vermiculite, barite, fluorite, copper, calcite, and zirconium. Other elements enriched in these deposits include manganese, strontium, tantalum, thorium, vanadium, and uranium. Carbonatite and peralkaline intrusion-related rare earth element deposits are presented together in this report because of the spatial, and potentially genetic, association between carbonatite and alkaline rocks. Although these rock types occur together at many locations, carbonatite and peralkaline intrusion-related rare earth element deposits are not generally found together.

  3. Immobilized xylenol orange as a sensitive element for fiber-optic sensors for thorium(4) and lead(2)

    International Nuclear Information System (INIS)

    Trutneva, L.M.; Shvoeva, O.P.; Savvin, S.B.

    1989-01-01

    A new type of carrier for immobilization of reagent-fibrous materials of polyacrylonitrile fiber filled with fine-dispersed ion exchanger during formation- was suggested when creating sensitive element of optical sensor for lead (2) and thorium(4). The highest sensitivity and contrast are achieved in color reactions with xylenol orange, immobilized on weak-base anion-exchanger. Detection limits are decreased down to 2x10 -8 M, the range of determined concentrations -5x10 -8 -1x10 -6 M, reproducibility Sr 0.05-0.10, the response forms during 1-10 minutes

  4. Arbuscular mycorrhiza reduces phytoextraction of uranium, thorium and other elements from phosphate rock

    DEFF Research Database (Denmark)

    Roos, Per; Jakobsen, Iver

    2008-01-01

    Uptake of metals from uranium-rich phosphate rock was studied in Medicago truncatula plants grown in symbiosis with the arbuscular mycorrhizal fungus Glomus intraradices or in the absence of mycorrhizas. Shoot concentrations of uranium and thorium were lower in mycorrhizal than in non......-mycorrhizal plants and root-to-shoot ratio of most metals was increased by mycorrhizas. This protective role of mycorrhizas was observed even at very high supplies of phosphate rock. In contrast, phosphorus uptake was similar at all levels of phosphate rock, suggesting that the P was unavailable to the plant......-fungus uptake systems. The results support the role of arbuscular mycorrhiza as being an important component in phytostabilization of uranium. This is the first study to report on mycorrhizal effect and the uptake and root-to-shoot transfer of thorium from phosphate rock. (c) 2007 Elsevier Ltd. All rights...

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

    Science.gov (United States)

    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.

  6. Determination of the elemental concentration of uranium and thorium in the products and by-products of amang tin tailings process

    Science.gov (United States)

    Alnour, I. A.; Wagiran, H.; Ibrahim, N.; Hamzah, S.; Elias, M. S.

    2017-01-01

    Amang or tin tailing is processed into concentrated ores and other economical valuable minerals such as monazite, zircon, xenotime, ilmenite etc. Besides that, the tailings from these ores may have a significant potential source of radiation exposure to amang plants' workers. This study was conducted to determine the elemental concentration of uranium and thorium in mineral samples collected from five amang tailing factories. The concentration of uranium and thorium was carried out by using instrumental neutron activation analysis (INAA) relative technique. The concentration of uranium and thorium in ppm obtained in this study are as follows: raw (189-1064) and (622-4965); monazite (1076-1988) and (3467-33578); xenotime 4053 and 5540; zircon (309-3090) and (387-6339); ilmenite (104-583) and (88-1205); rutile (212-889) and (44-1119); pyrite (7-43) and (9-132); and waste (5-338) and (9-1218) respectively. The analysis results shows that the monazite, xenotime and zircon have high content of uranium and thorium, whereas ilmenite, rutile, pyrite and waste have lower concentration compare with raw materials after tailing process. The highest values of uranium and thorium concentrations (4053 ± 428 ppm and 33578 ± 873 ppm, respectively) were observed in xenotime and monazite; whereas the lowest value was 5.48 ± 0.86 ppm of uranium recorded in waste (sand) and 9 ± 0.32 ppm of thorium for waste (sand) and pyrite.

  7. Anthropogenic Cycles of Rare Earth Elements

    Science.gov (United States)

    Du, X.; Graedel, T. E.

    2009-12-01

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

  8. Atmospheric thorium pollution and inhalation exposure in the largest rare earth mining and smelting area in China.

    Science.gov (United States)

    Wang, Lingqing; Zhong, Buqing; Liang, Tao; Xing, Baoshan; Zhu, Yifang

    2016-12-01

    Exposure to radionuclide thorium (Th) has generated widespread public concerns, mainly because of its radiological effects on human health. Activity levels of airborne 232 Th in total suspended particulate (TSP) were measured in the vicinity of the largest rare earth mine in China in August 2012 and March 2013. The mean activity concentrations of 232 Th in TSP ranged from 820μBqm -3 in a mining area in August 2012 to 39,720μBqm -3 in a smelting area in March 2013, much higher than the world reference of 0.5μBqm -3 . Multistatistical analysis and Kohonen's self-organizing maps suggested that 232 Th in TSP was mainly derived from rare earth mining and smelting practices. In addition, personal inhalation exposures to 232 Th associated with respirable particulate (PM 10 ) were also measured among local dwellers via personal monitoring. The mean dose values for different age groups in the smelting and mining areas ranged from 97.86 to 417μSvyear - 1 and from 101.03 to 430.83μSvyear -1 , respectively. These results indicate that people living in the study areas are exposed to high levels of widespread 232 Th. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Separation method of trivalent actinide and rare earth element

    International Nuclear Information System (INIS)

    Koma, Yoshikazu; Watabe, Masayuki; Nemoto, Shin-ichi.

    1997-01-01

    Trivalent actinides and rare earth elements are extracted to a solvent from highly acidic liquid wastes generated upon reprocessing of spent fuels. The concentration of nitric acid in the extracted solvent is reduced. Trivalent actinides and the rare earth elements contained in the solvent at low nitric acid concentration are separated from each other. Trivalent actinides and rare earth elements are extracted into a highly acidic solvent in the extracting step of trivalent actinides and rare earth elements. On the other hand, they can be separated by extraction only at a predetermined pH in the separation step of the rare earth elements and trivalent actinides. In the present invention, trivalent actinides and rare earth elements are separated after removing a predetermined amount of nitric acid from the solution obtained in the trivalent actinide and rare earth element extraction step to provide a proper acidic concentration. Accordingly, they can be separated satisfactorily. (T.M.)

  10. Recovery of radiogenic lead-208 from a residue of thorium and rare earths obtained during the operation of a thorium purification pilot plant; Separacao e recuperacao de chumbo-208 dos residuos de torio terras raras gerados na unidade piloto de purificacao de nitrato de torio

    Energy Technology Data Exchange (ETDEWEB)

    Seneda, Jose Antonio

    2006-07-01

    Brazil has a long tradition in thorium technology, from mineral dressing (monazite) to the nuclear grade thorium compounds. The estimate reserves are 1200,000. ton of ThO{sub 2}. As a consequence from the work of thorium purification pilot plant at Instituto de Pesquisas Energeticas e Nucleares-CNEN/IPEN-SP, about 25 ton of a sludge containing thorium and rare earths was accumulated. It comes as a raffinate and washing solutions from thorium solvent extraction. This sludge, a crude hydroxide named RETOTER contains thorium, rare earths and minor impurities including the radiogenic lead-208, with abundance 88.34 %. This work discusses the results of the studies and main parameters for its recovery by anionic ion exchange technique in the hydrochloric system. The isotope abundance of this lead was analyzed by high resolution mass spectrometer (ICPMS) and thermoionic mass spectrometer (TIMS) and the data was used to calculate the thermal neutron capture cross section. The value of {sigma}{gamma}{sup 0} = 14.6{+-}0.7 mb was found, quite different from the {sigma}{gamma}{sup 0} = 174.2 {+-} 7.0 mb measure cross section for the natural lead. Preliminary study for the thorium and rare earths separation and recovery was discussed as well. (author)

  11. Rare earth elements materials production from apatite ores

    International Nuclear Information System (INIS)

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

    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. (paper)

  12. Rare earth elements in river waters

    Science.gov (United States)

    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).

  13. Retention of alkaline earth elements in man

    International Nuclear Information System (INIS)

    Newton, D.

    1990-06-01

    The data on human metabolism and long-term retention of alkaline earth elements ( 133 Ba injected into six healthy male volunteers at age 25-81 y and 45 Ca and 85 Sr received by one healthy male volunteer) are presented. Excreta were collected for 2-3 weeks after injection of the tracer into an antecubital vein. Activity in urine, ashed faeces and early samples of blood plasma was determined by gamma-ray scintillation spectrometry. Whole body retention has been assessed through serial measurements of body radioactivity. The injected 133 Ba apparently became mainly skeletal within several days, much earlier than predicted by the ICRP model. The whole-body retention at 32 d ranged from 5 to 14%, the rate of loss correlating with the excretory plasma clearance rate. No age-related trends were identified in the metabolism of Ca and Sr. 2 refs, 2 figs

  14. Enhanced separation of rare earth elements

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-01

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

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

    Science.gov (United States)

    Chemin, Marie-Charlotte

    2015-04-01

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

  16. Wine Traceability with Rare Earth Elements

    Directory of Open Access Journals (Sweden)

    Maurizio Aceto

    2018-03-01

    Full Text Available The traceability of foodstuffs is now a relevant aspect of the food market. Scientific research has been devoted to addressing this issue by developing analytical protocols in order to find the link between soil and food items. In this view, chemical parameters that can act as soil markers are being sought. In this work, the role of rare earth elements (REEs as geochemical markers in the traceability of red wine is discussed. The REE distribution in samples from each step of the wine making process of Primitivo wine (produced in Southern Italy was determined using the highly sensitive inductively coupled plasma-mass spectrometry (ICP-MS technique. Samples analyzed include grapes, must, and wine samples after every step in the vinification process. The resulting data were compared to the REE distribution in the soil, revealing that the soil fingerprint is maintained in the intermediate products up to and including grape must. Fractionation occurs thereafter as a consequence of further external interventions, which tends to modify the REE profile.

  17. Lateritic, supergene rare earth element (REE) deposits

    Science.gov (United States)

    Cocker, Mark D.

    2014-01-01

    Intensive lateritic weathering of bedrock under tropical or sub-tropical climatic conditions can form a variety of secondary, supergene-type deposits. These secondary deposits may range in composition from aluminous bauxites to iron and niobium, and include rare earth elements (REE). Over 250 lateritic deposits of REE are currently known and many have been important sources of REE. In southeastern China, lateritic REE deposits, known as ion-adsorption type deposits, have been the world’s largest source of heavy REE (HREE). The lateritized upper parts of carbonatite intrusions are being investigated for REE in South America, Africa, Asia and Australia, with the Mt. Weld deposit in Australia being brought into production in late 2012. Lateritic REE deposits may be derived from a wide range of primary host rocks, but all have similar laterite and enrichment profiles, and are probably formed under similar climatic conditions. The weathering profile commonly consists of a depleted zone, an enriched zone, and a partially weathered zone which overlie the protolith. Lateritic weathering may commonly extend to depths of 30 to 60 m. REE are mobilized from the breakdown of primary REE-bearing minerals and redeposited in the enriched zone deeper in the weathering horizon as secondary minerals, as colloids, or adsorbed on other secondary minerals. Enrichment of REE may range from 3 to 10 times that of the source lithology; in some instances, enrichment may range up to 100 times.

  18. Chromatographic Techniques for Rare Earth Elements Analysis

    Science.gov (United States)

    Chen, Beibei; He, Man; Zhang, Huashan; Jiang, Zucheng; Hu, Bin

    2017-04-01

    The present capability of rare earth element (REE) analysis has been achieved by the development of two instrumental techniques. The efficiency of spectroscopic methods was extraordinarily improved for the detection and determination of REE traces in various materials. On the other hand, the determination of REEs very often depends on the preconcentration and separation of REEs, and chromatographic techniques are very powerful tools for the separation of REEs. By coupling with sensitive detectors, many ambitious analytical tasks can be fulfilled. Liquid chromatography is the most widely used technique. Different combinations of stationary phases and mobile phases could be used in ion exchange chromatography, ion chromatography, ion-pair reverse-phase chromatography and some other techniques. The application of gas chromatography is limited because only volatile compounds of REEs can be separated. Thin-layer and paper chromatography are techniques that cannot be directly coupled with suitable detectors, which limit their applications. For special demands, separations can be performed by capillary electrophoresis, which has very high separation efficiency.

  19. Laser isotope separation of rare earth elements.

    Science.gov (United States)

    Karlov, N V; Krynetskii, B B; Mishin, V A; Prokhorov, A M

    1978-03-15

    The experimental results on the laser isotope separation of the neodimium, samarium, europium, gadolinium, dysprosium, and erbium by the selective two-step photoionization are given. The rare earth elements have been chosen for the investigation because they constitute a good series of the very similar but different atoms that are heavy enough and allow experiments to be carried out that are representative enough. The experimental technique developed for the laser isotope separation experiments has been applied to measure the excitation energy transfer cross sections at the collisions in the gas of the same atoms ((153)Eu ? (151)Eu, sigma = 1.4 x 10(-13) cm(2)). The combination of the selective two-step photoionization and ion mass filtration allowed us to develop a very convenient technique for the precise measurement of hyperfine structure in the spectrum of odd isotopes. The examples of dysprosium and erbium are given. The technique is good for the rare and unstable isotopes as well. The ionization cross sections for the transition starting off the excited level have been estimated ( approximately 10(-17) cm(2)). For the example of gadolinium the possibility of creating neutral atomic vapor dense enough for laser isotope separation by the electron-beam evaporation technique has been demonstrated.

  20. Rare Earth Element Phases in Bauxite Residue

    Directory of Open Access Journals (Sweden)

    Johannes Vind

    2018-02-01

    Full Text Available The purpose of present work was to provide mineralogical insight into the rare earth element (REE phases in bauxite residue to improve REE recovering technologies. Experimental work was performed by electron probe microanalysis with energy dispersive as well as wavelength dispersive spectroscopy and transmission electron microscopy. REEs are found as discrete mineral particles in bauxite residue. Their sizes range from <1 μm to about 40 μm. In bauxite residue, the most abundant REE bearing phases are light REE (LREE ferrotitanates that form a solid solution between the phases with major compositions (REE,Ca,Na(Ti,FeO3 and (Ca,Na(Ti,FeO3. These are secondary phases formed during the Bayer process by an in-situ transformation of the precursor bauxite LREE phases. Compared to natural systems, the indicated solid solution resembles loparite-perovskite series. LREE particles often have a calcium ferrotitanate shell surrounding them that probably hinders their solubility. Minor amount of LREE carbonate and phosphate minerals as well as manganese-associated LREE phases are also present in bauxite residue. Heavy REEs occur in the same form as in bauxites, namely as yttrium phosphates. These results show that the Bayer process has an impact on the initial REE mineralogy contained in bauxite. Bauxite residue as well as selected bauxites are potentially good sources of REEs.

  1. Rare earth element ore geology of carbonatites

    Science.gov (United States)

    Verplanck, Philip L.; Mariano, Anthony N.; Mariano, Anthony

    2016-01-01

    For nearly 50 years, carbonatites have been the primary source of niobium and rare earth elements (REEs), in particular the light REEs, including La, Ce, Pr, and Nd. Carbonatites are a relatively rare type of igneous rock composed of greater than 50 vol % primary carbonate minerals, primarily calcite and/or dolomite, and contain the highest concentrations of REEs of any igneous rocks. Although there are more than 500 known carbonatites in the world, currently only four are being mined for REEs: the Bayan Obo, Maoniuping, and Dalucao deposits in China, and the Mountain Pass deposit in California, United States. The carbonatite-derived laterite deposit at Mount Weld in Western Australia is also a REE producer. In addition to REEs, carbonatite-related deposits are the primary source of Nb, with the Araxá deposit, a carbonatite-derived laterite in Minas Gerais state, Brazil, being the dominant producer. Other commodities produced from carbonatite-related deposits include phosphates, iron, fluorite, copper, vanadium, titanium, uranium, and calcite.Types of ores include those formed as primary magmatic minerals, from late magmatic hydrothermal fluids, and by supergene enrichment in weathered horizons. Although the principal REE-bearing mineral phases include fluorocarbonates (bastnäsite, parisite, and synchysite), hydrated carbonates (ancylite), and phosphates (monazite and apatite), the dominant mineral exploited at most mines is bastnäsite. Bastnäsite typically is coarse grained and contains approximately 75 wt % RE2O3 (rare earth oxides; REOs). Processes responsible for REE enrichment include fractional crystallization of the carbonatitic magma, enrichment of REEs in orthomagmatic or hydrothermal fluids and subsequent precipitation or subsolidus metasomatic redistribution of REEs, and breakdown of primary carbonatitic mineral phases by chemical weathering and sequestration of REEs in secondary minerals or in association with clays. Carbonatites are primarily

  2. Accumulation of rare earth elements by siderophore-forming ...

    Indian Academy of Sciences (India)

    In this study, Arthrobacter luteolus, isolated from rare earth environment of Chavara (Quilon district, Kerala, India), were found to produce catechol-type siderophores. The bacterial strain accumulated rare earth elements such as samarium and scandium. The siderophores may play a role in the accumulation of rare earth ...

  3. Geostationary earth observatories - Key elements of NASA's 'Mission to Planet Earth'

    Science.gov (United States)

    Snoddy, William C.; Keller, Vernon W.

    1991-01-01

    The scientific rationale, required instrumentation, observatory configuration, and data system of the Geostationary Earth Observatory (GEO) element of NASA's Mission to Planet Earth program are discussed. Physical characteristics of GEO candidate instruments are listed.

  4. Advances in chromatography of the rare earth elements (review)

    International Nuclear Information System (INIS)

    Oguma, Koichi; Kuroda, Rokuro; Shimizu, Tsuneo.

    1995-01-01

    A review is presented which covers liquid chromatography, gas chromatography, and related techniques. This article intends to describe the chromatographic methods playing an important role in the separation of the rare earth elements. Special attention is paid to the usefulness of various types of liquid chromatography which enable the complete mutual separation of the rare earth elements. Applications are also discussed. (author) 161 refs

  5. Preliminary investigation of the rare earth element (REE ...

    African Journals Online (AJOL)

    ... in the light rare earth elements but a significant depletion of the heavy rare earth elements similar to the seawater derived shales. This signifies that the shale precursors are granitic rocks with large proportions of alkali feldspars and low contents of plagioclase feldspars. Journal of Mining and Geology Vol. 43 (2) 2007: pp.

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

    Science.gov (United States)

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

    2009-06-01

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

  7. Enzymatic determination of rare earth elements using pyrophosphatases

    International Nuclear Information System (INIS)

    Shekhovtsova, T.N.; Pirogova, S.V.; Fedorova, O.M.; Dolmanova, I.F.; Bajkov, A.A.

    1993-01-01

    A highly sensitive(determination limit 8x10 -6 -4x10 -4 μ g/m) and selective enzymatic method for determination of rare earth elements has been developed. The method is based on inhibition action of rare earths on the catalytic activity of pyrophosphates isolated from bakery geast and E.Coli. The mechanism of the rare earth element action, corresponding to competitive inhibition, has been established

  8. Enzymatic determination of rare earth elements by use of pyrophosphotases

    International Nuclear Information System (INIS)

    Shekhovtseva, T.N.; Pirogova, S.V.; Fedorova, O.M.; Dolmanova, I.F.; Bajkov, A.A.

    1993-01-01

    A highly sensitive (determination limit 8 x 10 -6 - 4 x 10 -4 μg/ml) and selective enzymatic method for determination of rare earth elements has been developed. The method is based on inhibition action of rare earths on the catalytic activity of pyrophosphates isolated from bakery geast and E. Coli. The mechanism of the rare earth element action, corresponding to competitive inhibition, has been established

  9. Naturally Occurring Radionuclides and Rare Earth Elements Pattern in Weathered Japanese Soil Samples

    International Nuclear Information System (INIS)

    Sahoo, S.K.; Hosoda, M.; Takahashi, H.; Sorimachi, A.; Ishikawa, T.; Tokonami, S.; Uchida, S.

    2011-01-01

    From the viewpoint of radiation protection, determination of natural radionuclides e.g. thorium and uranium in soil samples are important. Accurate methods for determination of Th and U is gaining importance. The geochemical behavior of Th, U and rare earth elements (REEs) are relatively close to one another while compared to other elements in geological environment. Radioactive elements like 232 Th and 238 U along with their decay products (e.g. 226 Ra) are present in most of the environmental matrices and can be transferred to living bodies by different pathways that can lead to sources of exposure of man. Therefore, it is necessary to monitor these natural radionuclides in weathered soil samples to assess the possible hazards. The activity concentrations of 226 Ra, 228 Th, and 40 K in soils have been measured using a g γ-ray spectroscopy system with high purity germanium detector. The thorium, uranium and REEs were determined from the same sample using inductively coupled plasma mass spectrometry (ICP-MS). Granitic rocks contain higher amounts of Th, U 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, as soils are complex heterogeneous mixture of organic and inorganic solids, water and gases. In this paper, we have discussed about distribution pattern of 226 Ra, 232 Th and 238 U along with REEs in soil samples of weathered acid rock (granite and ryolite) collected from two prefectures in Japan: 1. Gifu and 2. Okinawa. (author)

  10. Rare earth element deposits in China

    Science.gov (United States)

    Xie, Yu-Ling; Hou, Zeng-qian; Goldfarb, Richard J.; Guo, Xiang; Wang, Lei

    2016-01-01

    China is the world’s leading rare earth element (REE) producer and hosts a variety of deposit types. Carbonatite- related REE deposits, the most significant deposit type, include two giant deposits presently being mined in China, Bayan Obo and Maoniuping, the first and third largest deposits of this type in the world, respectively. The carbonatite-related deposits host the majority of China’s REE resource and are the primary supplier of the world’s light REE. The REE-bearing clay deposits, or ion adsorption-type deposits, are second in importance and are the main source in China for heavy REE resources. Other REE resources include those within monazite or xenotime placers, beach placers, alkaline granites, pegmatites, and hydrothermal veins, as well as some additional deposit types in which REE are recovered as by-products. Carbonatite-related REE deposits in China occur along craton margins, both in rifts (e.g., Bayan Obo) and in reactivated transpressional margins (e.g., Maoniuping). They comprise those along the northern, eastern, and southern margins of the North China block, and along the western margin of the Yangtze block. Major structural features along the craton margins provide first-order controls for REE-related Proterozoic to Cenozoic carbonatite alkaline complexes; these are emplaced in continental margin rifts or strike-slip faults. The ion adsorption-type REE deposits, mainly situated in the South China block, are genetically linked to the weathering of granite and, less commonly, volcanic rocks and lamprophyres. Indosinian (early Mesozoic) and Yanshanian (late Mesozoic) granites are the most important parent rocks for these REE deposits, although Caledonian (early Paleozoic) granites are also of local importance. The primary REE enrichment is hosted in various mineral phases in the igneous rocks and, during the weathering process, the REE are released and adsorbed by clay minerals in the weathering profile. Currently, these REE-rich clays are

  11. Sc, Y, La-Lu - Rare Earth Elements

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    At present extensive efforts are being made in completing work on system number Rare Earth Elements. Part A is devoted to the occurrence of these elements on the earth and in the universe. Part B deals with the pure metals; the 7 volumes published cover the description of the separation from the raw materials, the preparation of pure metals,their uses and toxicology, the physical properties of nuclei, atoms, molecules, and isotopes; in addition the behavior of ions in solution and the electrochemical behavior of rare earth elements are described. The compounds are described in Part C. Part D with 6 volumes has been devoted to the description of coordination compounds and is completed. The volume ''Rare Earth Elements C 10'' deals with the rare earth tellurides, oxide tellurides, tellurates, telluride halides, tellurate halides, sulfide tellurides, selenide tellurides, and alkali rare earth tellurates. Another topic of this volume are the compounds of the rare earth elements with polonium. So far as meaningful and in accordance with all earlier volumes of ''Rare Earth Elements'' Series C, comparative data are presented in sections preceding treatment of the individual compounds and systems

  12. Rare earth element association with foraminifera

    Science.gov (United States)

    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

  13. Features of rare earth element (3) complexing

    International Nuclear Information System (INIS)

    Martynenko, L.I.

    1991-01-01

    Reasons for nonobeyance to the regularity of tetrad ''W'' effect of rare earth chelate complex compounds are discussed in the review. The concept of metal-ligand ionic bond in rare earth complexes is put in the basis of the consideration. From this viewpoint mutual influence of ligands in lower, higher, polynuclear and different-ligand complexes, formed by the ligands of low, medium and high denticity, is discussed. Problems of intermolecular interaction of complexes with different structure are considered in relation to problems of variation of chelate volatility and selectivity in the processes of sublimation and precipitation

  14. An investigation on the thorium lung burden and its health effects on the workers in a rare-earth refinery factory, Baotou, China

    International Nuclear Information System (INIS)

    Chen, Xing-an; Chen, Yong-e

    2008-01-01

    The purpose of this paper is to present the thorium lung burden and its health effects among the workers of Huamei Rare-earth Refinery Factory, Baotou, China. The methods used is a combination between exhaled thoron activity measurement and the physical examination (peripheral blood counts, hepatic function tests, lung function tests, chest X-ray radiograph) as well as the measurement of dust concentrations, radon and thoron short lived progeny concentration in the air of the workshops. The results showed that the four workshops are thought to be the radiological workplaces. The dust air concentrations in different workshops range from 1.34∼8.17 mg/m 3 . The average a potential energy value of radon short-lived progeny are in the range from 24 to 285 MeV/L; while the average a-progeny are in the range from 159 to 5972 MeV/L. The thorium lung burdens of 9 dust-exposed workers are higher than one investigation level (2.22 Bq) and the highest one is 3.33 Bq. The results of radiography, hematological parameters and hepatic parameters for the dust exposed workers examined are all within the normal range, while the lung function of 27 cases among the 91 dust exposed workers are abnormal. Our conclusion is that the radiological protection problems are existed in rare-earth refinery factory, mainly the high thorium-containing dust air concentration and the high a potential energy of the thoron short-lived progeny in the air of different workshops. Ventilation should be improved. Long-term follow-up study is necessary. (author)

  15. Alloying Characteristics of the Rare Earth Elements with the Transition Elements

    National Research Council Canada - National Science Library

    Elliott, Rodney

    1964-01-01

    The alloying characteristics of the rare earth elements with the transition metals undergo a radical change as the atomic number of the transition series increases - - transition elements in Groups...

  16. Determination of trace element concentrations and stable lead, uranium and thorium isotope ratios by quadrupole-ICP-MS in NORM and NORM-polluted sample leachates

    International Nuclear Information System (INIS)

    Mas, J.L.; Villa, M.; Hurtado, S.; García-Tenorio, R.

    2012-01-01

    Highlights: ► Polluted sediment and NORM samples. ► An efficient yet fast process allowing multi-parametric determinations in 206 Pb/ 207 Pb/ 208 Pb, 238 U/ 234 U and 232 Th/ 230 Th isotope ratios using a single sample aliquot and a single instrument (ICP-QMS). Eichrom UTEVA ® extraction chromatography minicolumns were used to separate uranium and thorium in sample leachates. Independent ICP-MS determinations of uranium and thorium isotope ratios were carried out afterwards. Previously a small aliquot of the leachate was used for the determination of trace element concentrations and lead isotope ratios. Several radiochemical arrangements were tested to get maximum performances and simplicity of the method. The performances of the method were studied in terms of chemical yields of uranium and thorium and removal of the potentially interfering elements. The established method was applied to samples from a chemical industry and sediments collected in a NORM-polluted scenario. The results obtained from our method allowed us to infer not only the extent, but also the sources of the contamination in the area.

  17. Use of thorium as tracer on study of groundwater of Botucatu sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Paulo Augusto d' A.; Menezes, Maria Angela B.C. de; Moreira, Rubens Martins; Reis Junior, Aluisio Souza; Kastner, Geraldo Frederico, E-mail: paap@cdtn.br, E-mail: menezes@cdtn.br, E-mail: rubens@cdtn.br, E-mail: reisas@cdtn.br, E-mail: gfk@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Thorium in some mineral compounds is very difficult to be dissolved in aqueous medium. To study the mobility of thorium in water, one alternative is to complex this element with EDTA, becoming possible to follow the behavior of thorium this medium. This way, in groundwater with low natural radioactivity and low {sup 232}Th activity, thorium can be used as a tracer. This paper describes the application of the complex Th-EDTA as a tracer applying the solution trough a sandstone sample made by rock from Botucatu Sandstone. The objective was to simulate the flow of groundwater inside the original rock aiming at future use of rare-earth elements complexed with EDTA as tracer. Alpha spectrometry technique was used to determine {sup 232}Th in the water samples with {sup 230}Th as inner-standard. (author)

  18. Rare earths and thorium

    International Nuclear Information System (INIS)

    Ward, J.

    1984-01-01

    While domestic production of monazite concentrates decreased slightly in 1981, Australian exports increased to a record level of 14000 t. Information on production, prices and resources is followed by a world review. In recent years Australia, India, Malaysia, Brazil and USA have produced the bulk of world output of monazite concentrates

  19. Determination of Barium and selected rare-earth elements in geological materials employing a HpGe detector by radioisotope excited x-ray fluorescence

    International Nuclear Information System (INIS)

    LaBrecque, J.J.; Preiss, I.L.

    1984-01-01

    The laterite material (geological) from Cerro Impacto was first studied by air radiometric techniques in the 1970's and was found to have an abnormally high radioactive background. Further studies showed this deposit to be rich in thorium, columbium, barium and rare-earth elements (mostly La, Ce, Pr and Nd). A similar work has been reported for the analysis of Brazil's lateritic material from Morro do Ferro to determine elemental compositions (including barium and rare-earth elements) and its relationship to the mobilization of thorium from the deposit using a Co-57 radioisotope source. The objective of this work was to develop an analytical method to determine barium and rare-earth element present in Venezuelan lateritic material from Cerro Impacto. We have employed a method before, employing a Si(Li) detector, but due to the low detection efficiencies in the rare-earth K-lines region (about 30 KeV - 40 KeV), we have decided to study the improvement in sensitivities and detection limits using an hyperpure germanium detector

  20. Rare-earth elements in granites: concentration and distribution pattern

    International Nuclear Information System (INIS)

    Galindo, A.C.

    1983-01-01

    The geochemistry of rare earth elements in granites is studied. The rare earth element (REE) distribution pattern in granites is characterized by a smooth curve with decreasing concentrations from La to Lu, and frequently a marked Eu negative anomaly. It seems to exist relationship between granite genesis and its REE pattern, in that bodies of primary (magmatic differentiation) origin always show this negative Eu anomaly, while those bodies generated by crustal anatexis do not show this anomaly. (E.G.) [pt

  1. Thorium in nuclear fuel

    International Nuclear Information System (INIS)

    Stankevicius, Alejandro

    2012-01-01

    We revise the advantages and possible problems on the use of thorium as a nuclear fuel instead of uranium. The following aspects are considered: 1) In the world there are three times more thorium than uranium 2) In spite that thorium in his natural form it is not a fisil, under neutron irradiation, is possible to transform it to uranium 233, a fisil of a high quality. 3) His ceramic oxides properties are superior to uranium or plutonium oxides. 4) During the irradiation the U 233 due to n,2n reaction produce small quantities of U 232 and his decay daughters' bismuth 212 and thallium 208 witch are strong gamma source. In turn thorium 228 and uranium 232 became, in time anti-proliferate due to there radiation intensity. 5) As it is described in here and experiments done in several countries reactors PHWR can be adapted to the use of thorium as a fuel element 6) As a problem we should mentioned that the different steps in the process must be done under strong radiation shielding and using only automatized equipment s (author)

  2. Thorium fuel cycle management

    International Nuclear Information System (INIS)

    Zajac, R.; Darilek, P.; Breza, J.; Necas, V.

    2010-01-01

    In this presentation author deals with the thorium fuel cycle management. Description of the thorium fuels and thorium fuel cycle benefits and challenges as well as thorium fuel calculations performed by the computer code HELIOS are presented.

  3. Rare earth elements in a uranium deposit in Pedra, Pernambuco, Brazil

    International Nuclear Information System (INIS)

    Damascena, Kennedy Francys Rodrigues; Amaral, Romilton dos Santos; Santos Junior, Jose Araujo dos; Bezerra, Jairo Dias; Oliveira, Iane Andrade de; Silva, Alberto Antonio da

    2013-01-01

    Rare Earth Elements (REEs) are similar in the physical and chemical properties of their compounds and are most commonly found in nature associated with terrestrial radionuclides. The high interest in conducting research on REEs is due to their multiple applications and high economic value. In this light, the present study analyzed samples of soil and rocks from an anomalous area replete with uranium and thorium, in the town of Pedra, Pernambuco, Brazil, in an attempt to identify the occurrence and concentrations of these elements. For these analyses, neutron activation, followed by high-resolution gamma spectrometry, was used to define the REEs. The following REEs were identified in the study area: La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, and Sc. The most abundant elements in the region, within samples of soil and rock, respectively, were: Ce (63-503 mg.kg -1 / 19.6 to 2243.5 mg.kg -1 ), Nd (25.0 to 249.0 mg.kg -1 / 3.8 to 1951.0 mg.kg -1 ), and La (30.6 to 253.0 mg.kg -1 / 12.1 to 517.0 mg.kg -1 ). The other REEs presented concentrations of between the detection limit and 46.0 mg.kg -1 . The results indicate that the Ce, La, and Nd concentrations appeared in up to 12 times the average occurrences in the earth's crust and up to 4.6 times higher than the averages reported in studies worldwide, including Brazil. Therefore, further studies are warranted to examine the economic viability of REEs in the area and to confirm the occurrence of these anomalous elements in the studied region. (author)

  4. Determination of trace element concentrations and stable lead, uranium and thorium isotope ratios by quadrupole-ICP-MS in NORM and NORM-polluted sample leachates

    Energy Technology Data Exchange (ETDEWEB)

    Mas, J.L., E-mail: ppmasb@us.es [Dpto. Fisica Aplicada I, EPS, Universidad de Sevilla, 41012 Sevilla (Spain); Villa, M. [Servicio de Radioisotopos, Centro de Investigacion, Tecnologia e Innovacion (CITIUS), Universidad de Sevilla, Avda. Reina Mercedes 4b, 41012 Sevilla (Spain); Dpto. Fisica Aplicada II, ETS de Arquitectura, Universidad de Sevilla, Avda. Reina Mercedes 2, 41012 Sevilla (Spain); Hurtado, S. [Servicio de Radioisotopos, Centro de Investigacion, Tecnologia e Innovacion (CITIUS), Universidad de Sevilla, Avda. Reina Mercedes 4b, 41012 Sevilla (Spain); Garcia-Tenorio, R. [Dpto. Fisica Aplicada II, ETS de Arquitectura, Universidad de Sevilla, Avda. Reina Mercedes 2, 41012 Sevilla (Spain)

    2012-02-29

    Highlights: Black-Right-Pointing-Pointer Polluted sediment and NORM samples. Black-Right-Pointing-Pointer An efficient yet fast process allowing multi-parametric determinations in <3 days. Black-Right-Pointing-Pointer Trace element concentrations, Pb, Th and U isotope ratios with a single instrument. - Abstract: This work focuses on the monitoring of the potential pollution in scenarios that involve NORM-related industrial activities (environmental or in-door scenarios). The objective was to develop a method to determine extent and origin of the contamination, suitable for monitoring (i.e. simple, fast and economical) and avoiding the use of too many different instruments. It is presented a radiochemical method that allows the determination of trace element concentrations and {sup 206}Pb/{sup 207}Pb/{sup 208}Pb, {sup 238}U/{sup 234}U and {sup 232}Th/{sup 230}Th isotope ratios using a single sample aliquot and a single instrument (ICP-QMS). Eichrom UTEVA{sup Registered-Sign} extraction chromatography minicolumns were used to separate uranium and thorium in sample leachates. Independent ICP-MS determinations of uranium and thorium isotope ratios were carried out afterwards. Previously a small aliquot of the leachate was used for the determination of trace element concentrations and lead isotope ratios. Several radiochemical arrangements were tested to get maximum performances and simplicity of the method. The performances of the method were studied in terms of chemical yields of uranium and thorium and removal of the potentially interfering elements. The established method was applied to samples from a chemical industry and sediments collected in a NORM-polluted scenario. The results obtained from our method allowed us to infer not only the extent, but also the sources of the contamination in the area.

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

    Czech Academy of Sciences Publication Activity Database

    Borovička, Jan; Kubrová, J.; Rohovec, Jan; Řanda, Zdeněk; Dunn, C. E.

    2011-01-01

    Roč. 24, č. 5 (2011), s. 837-845 ISSN 0966-0844 R&D Projects: GA AV ČR IAA600480801 Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z10480505 Keywords : ICP-MS * ENAA * REE * fungi * bioaccumulation * metals Subject RIV: DD - Geochemistry Impact factor: 2.823, year: 2011

  6. Concomitant Leaching and Electrochemical Extraction of Rare Earth Elements from Monazite.

    Science.gov (United States)

    Maes, Synthia; Zhuang, Wei-Qin; Rabaey, Korneel; Alvarez-Cohen, Lisa; Hennebel, Tom

    2017-02-07

    Rare earth elements (REEs) have become increasingly important in modern day technologies. Unfortunately, their recycling is currently limited, and the conventional technologies for their extraction and purification are exceedingly energy and chemical intensive. New sustainable technologies for REE extraction from both primary and secondary resources would be extremely beneficial. This research investigated a two-stage recovery strategy focused on the recovery of neodymium (Nd) and lanthanum (La) from monazite ore that combines microbially based leaching (using citric acid and spent fungal supernatant) with electrochemical extraction. Pretreating the phosphate-based monazite rock (via roasting) dramatically increased the microbial REE leaching efficiency. Batch experiments demonstrated the effective and continued leaching of REEs by recycled citric acid, with up to 392 mg of Nd L -1 and 281 mg of La L -1 leached during seven consecutive 24 h cycles. Neodymium was further extracted in the catholyte of a three-compartment electrochemical system, with up to 880 mg of Nd L -1 achieved within 4 days (at 40 A m -2 ). Meanwhile, the radioactive element thorium and counterions phosphate and citrate were separated effectively from the REEs in the anolyte, favoring REE extraction and allowing sustainable reuse of the leaching agent. This study shows a promising technology that is suitable for primary ores and can further be optimized for secondary resources.

  7. Rare earth elements and select actinoids in the Canadian House Dust Study.

    Science.gov (United States)

    Rasmussen, P E; Levesque, C; Chénier, M; Gardner, H D

    2017-09-01

    Nationally representative baseline data are presented for rare earth elements (REE), thorium (Th) and uranium (U) in house dust sampled from 1025 urban homes, in units of concentrations (μg g -1 ), loadings (μg m -2 ), and loading rates (ng m -2  d -1 ). Spearman rank correlations indicate that, in addition to outdoor sources, consumer products and building materials can influence indoor dust concentrations of REE, Th, and U. Correlations (Praw materials used in consumer products, such as U and Th impurities in bentonite clay used in cat litter, and REE impurities in phosphates used for a variety of applications including dog food and building materials. Median gastric bioaccessibility (pH 1.5) of most REE in dust ranges from about 20% to 29%. Household vacuum samples correlate with fresh dust samples from the same homes (P<.001 for all investigated elements). © 2017 Her Majesty the Queen in Right of Canada Indoor Air © 2017 John Wiley & Sons Ltd.

  8. Implications of Competition for Rare Earth Elements (REE) in Africa

    Science.gov (United States)

    2011-03-15

    bauxite , a mineral critical to the production of aluminum used in the manufacture of military airframes. Southeastern Europe became critically...rare earth element mine located in the Mojave Desert at Mountain Pass, California. The Transitional era lasted from 1985 to 1991 as global dominance...positioned on the Periodic Table of Elements39 13 REEs are often obtained as a byproduct from the mining of other ores such as: gold (Au), iron

  9. PIXE methodology of rare earth element analysis and its applications

    International Nuclear Information System (INIS)

    Ma Xinpei

    1992-01-01

    The Proton Induced X-ray Emission (PIXE) methodology of rare earth element (REEs) analysis is discussed, including the significance of REE analysis, the principle of PIXE applied to REE, selection of characteristic X-ray for Lanthanide series elements, deconvolution of highly over lapped PIXE spectrum and minimum detection limit (MDL) of REEs. Some practical applications are presented. And the specialities of PIXE analysis to the high pure REE chemicals are discussed. (author)

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

    Directory of Open Access Journals (Sweden)

    Cristina Bumbac

    2013-01-01

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

  11. Determination of rare earth and refractory trace element ...

    Indian Academy of Sciences (India)

    Abundances of rare earth and several other refractory trace elements in a set of early solar system objects isolated from two primitive carbonaceous chondrites were determined using the procedures devised by us. The results suggest that some of these objects could be high temperature nebular condensates, while others ...

  12. Accumulation of rare earth elements by siderophore- forming ...

    Indian Academy of Sciences (India)

    2012-01-08

    Jan 8, 2012 ... The influence of siderophore on the accumulation of rare earth elements by bacteria has been extensively discussed. [Challaraj Emmanuel ES .... The presence of REEs was measured in bacterial cultures after acid-digesting the cell pellet ..... physical-chemical properties. J. Gen. Microbiol. 107 319–328.

  13. Rare earth element behaviour in zironc-melt systems

    NARCIS (Netherlands)

    Hanchar, John M.; van Westrenen, W.

    2007-01-01

    Natural zircon crystals incorporate rare earth elements (REE) into their structure at concentrations determined by the pressure, temperature, and composition of their growth environment. In principle, REE concentrations in magmatic zircon crystals can be used to infer their conditions of growth and

  14. Geological research on rare earth elements, results and outlook

    International Nuclear Information System (INIS)

    Fortin, H

    1999-01-01

    This is a report of the geological investigation of rare earth elements carried out by CCHEN and ENAMI (Empresa Nacional de Mineria) over 70,000 square kilometers in Chile's northern coastal mountain range. Twenty areas were identified with sphena, davidite, ilmenite, pyroxene, anatase and magnetite minerals containing 0.3 kg/t to 6.0 kg/t of rare earth elements. Additional research on Cerro Carmen Prospect, located near Diego de Almagro, define it as a metasomatic deposit, hosted in metamorphic contact rocks, between andesites (Pliensbachian to early Jurassic) and intrusive monzonitic rocks. This information increases knowledge about the metallogenesis of Chile's copper - iron - rare earth - uranium deposits and the application of this geological model of ore deposits as defined in Australia's Olympic Dam

  15. Minerals yearbook, 1991: Thorium. Annual report

    International Nuclear Information System (INIS)

    Hedrick, J.B.

    1992-10-01

    Domestic mine production data for thorium-bearing monazite are developed by the U.S. Bureau of Mines from a voluntary survey of U.S. operations entitled, 'Rare Earths, Thorium, and Scandium.' The one mine to which a survey form was sent responded, representing 100% of domestic production. Mine production data for thorium are withheld to avoid disclosing company proprietary data. Statistics on domestic thorium consumption are developed by surveying various processors and end users, evaluating import-export data, and analyzing Government stockpile shipments

  16. Effects of radioactive by-products along the extraction of rare earth elements on aquatic and terrestrial organisms

    International Nuclear Information System (INIS)

    Findeiss, Matthias

    2016-01-01

    Lanthanides, also called rare earth elements (REE) are key elements in modern technologies and especially in green technologies such as energy generation through wind power. Thus, they are of considerable economic importance with a global production of around 124 000 t REE per year. A detailed environmental assessment with identification of all risks is the foundation to assess the sustainability of mining, processing and separation processes. Rare earth elements usually are found together with actinides such as uranium and thorium. Therefore, actinides and their decay products are simultaneously enriched during the processing of REE. In addition to conventional REE minerals such as monazite or bastnasite, the mineral eudialyte can be used as a REE source. Even though, the total share of REE is low, the most important REE needed for industrial usages are strongly represented in eudialyte. Furthermore, the proportion of radioactive impurities is very low. Eudialyte is currently not used as source mineral, but might play a bigger role on the global market in the future.Little information about the environmental impacts of REE-production is available to the public, in particular with regard to its radioactive by-products. Thorium is the most prominent of these and has therefore been characterized in detail for its ecotoxicity. A first goal of this work was to evaluate the a- emitter thorium and its impact on the environment. To this aim, an intensive literature search was conducted and results were prepared including the long-term effects of thorium dust and gaseous emissions. Therefore and because ecotoxicological testing of gaseous emissions was technically difficult and environmentally less relevant - unlike its immense impact for exposed industrial workers and bystanders - the water effluent und solid waste streams were investigated with aquatic and terrestrial toxicological experiments. The knowledge gained is meant to supplement the missing data for thorium. A

  17. Associative correlations between TH and U and rare earth elements in the living matter

    OpenAIRE

    Коваль, Е. В.; Барановская, Наталья Владимировна

    2016-01-01

    The article introduces the results of studying the correlations between radioactive and rare earth elements in living matter of the Tomsk region. Peculiarities in the distribution of districts for ratios of radioactive elements in the rare earth elements.

  18. Uncovering the end uses of the rare earth elements.

    Science.gov (United States)

    Du, Xiaoyue; Graedel, T E

    2013-09-01

    The rare earth elements (REE) are a group of fifteen elements with unique properties that make them indispensable for a wide variety of emerging and conventional established technologies. However, quantitative knowledge of REE remains sparse, despite the current heightened interest in future availability of the resources. Mining is heavily concentrated in China, whose monopoly position and potential restriction of exports render primary supply vulnerable to short term disruption. We have drawn upon the published literature and unpublished materials in different languages to derive the first quantitative annual domestic production by end use of individual rare earth elements from 1995 to 2007. The information is illustrated in Sankey diagrams for the years 1995 and 2007. Other years are available in the supporting information. Comparing 1995 and 2007, the production of the rare earth elements in China, Japan, and the US changed dramatically in quantities and structure. The information can provide a solid foundation for industries, academic institutions and governments to make decisions and develop strategies. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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.

  20. Spectroscopic identification of rare earth elements in phosphate glass

    Science.gov (United States)

    Devangad, Praveen; Tamboli, Maktum; Muhammed Shameem, K. M.; Nayak, Rajesh; Patil, Ajeetkumar; Unnikrishnan, V. K.; Santhosh, C.; Kumar, G. A.

    2018-01-01

    In this work, rare earth-doped phosphate glasses were synthesized and characterized using three different spectroscopic techniques. The absorption spectra of the prepared praseodymium (Pr) and samarium (Sm) doped glasses, recorded by a UV–VIS-NIR spectrophotometer, show the characteristic absorption bands of these elements. To confirm this inference, laser-induced fluorescence spectra of Pr and Sm were obtained at a laser excitation of 442 nm. Their emission bands are reported here. The elemental analysis of these samples was carried out using a laser-induced breakdown spectroscopy (LIBS) system. Characteristic emission lines of Pr and Sm have been identified and reported by the recorded LIBS spectra of glass samples. Results prove that using these three complimentary spectroscopic techniques (absorption, fluorescence and LIBS), we can meaningfully characterize rare earth-doped glass samples.

  1. Interpreting granulite facies events through rare earth element partitioning arrays

    OpenAIRE

    Taylor, R. J. M.; Clark, C; Harley, SL; Kylander-Clark, ARC; Hacker, BR; Kinny, PD

    2017-01-01

    The use of rare earth element (REE) partition coefficients is an increasingly common tool in metamorphic studies, linking the growth or modification of accessory mineral geochronometers to the bulk silicate mineral assemblage. The most commonly used mineral pair for the study of high-grade metamorphic rocks is zircon and garnet. The link from U–Pb ages provided by zircon to the P–T information recorded by garnet can be interpreted in relation to experimental data. The simplistic approach of t...

  2. Recovery of thorium from monazite

    International Nuclear Information System (INIS)

    Karve, V.M.; Mukherjee, T.K.

    1997-01-01

    The process practised in the monazite processing plant involves caustic soda digestion of finely ground monazite followed by aqueous processing to recover mixed rare earth chloride solution, thorium and uranium values in the form of hydroxide cake and tri sodium phosphate as a byproduct

  3. Volatile elements - water, carbon, nitrogen, noble gases - on Earth

    Science.gov (United States)

    Marty, B.

    2017-12-01

    Understanding the origin and evolution of life-bearing volatile elements (water, carbon, nitrogen) on Earth is a fruitful and debated area of research. In his pioneering work, W.W. Rubey inferred that the terrestrial atmosphere and the oceans formed from degassing of the mantle through geological periods of time. Early works on noble gas isotopes were consistent with this view and proposed a catastrophic event of mantle degassing early in Earth's history. We now have evidence, mainly from noble gas isotopes, that several cosmochemical sources contributed water and other volatiles at different stages of Earth's accretion. Potential contributors include the protosolar nebula gas that equilibrated with magma oceans, inner solar system bodies now represented by chondrites, and comets. Stable isotope ratios suggest volatiles where primarily sourced by planetary bodies from the inner solar system. However, recent measurements by the European Space Agency Rosetta probe on the coma of Comet 67P/Churyumov-Gerasimenko permit to set quantitative constraints on the cometary contribution to the surface of our planet. The surface and mantle reservoirs volatile elements exchanged volatile elements through time, with rates that are still uncertain. Some mantle regions remained isolated from whole mantle convection within the first tens to hundreds million years after start of solar system formation. These regions, now sampled by some mantle plumes (e.g., Iceland, Eifel) preserved their volatile load, as indicated by extinct and extant radioactivity systems. The abundance of volatile elements in the mantle is still not well known. Different approaches, such as high pressure experimental petrology, noble gas geochemistry, modelling, resulted in somewhat contrasted estimates, varying over one order of magnitude for water. Comparative planetology, that is, the study of volatiles on the Moon, Venus, Mars, Vesta, will shed light on the sources and strengths of these elements in the

  4. Rare earth elements as a by-catch of sedimentary deposits. Exploration program of rare earth elements

    International Nuclear Information System (INIS)

    Linhardt, E.; Gebhardt, A.

    2014-01-01

    The increasing demand for rare earth elements (REE) in the field of ''green technologies'' on the one hand and the shortage of raw materials on the world markets on the other hand confronted also Bavaria as an industrial location with growing supply problems in these ''high tech raw materials''. The aim of exploration was the clarification of the feedstock REE potential of heavy mineral concentrates which are obtained in the industrial extraction and processing of sand and kaolin in existing extraction operations in northern Bavaria as by catch and are potentially winnable or marketable. The in-depth investigation enabled the potential of found rare earth elements and other high-tech metal oxides that can be classified as very likely find it in terms of an economic recovery. [de

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

    Science.gov (United States)

    Du, Xiaoyue; Graedel, T. E.

    2011-11-01

    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.

  6. Uncovering the global life cycles of the rare earth elements.

    Science.gov (United States)

    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.

  7. The importance of thorium in the context of the generation in advanced reactors and the IPEN's experience

    International Nuclear Information System (INIS)

    Lainetti, Paulo E.O.; Mindrisz, Ana C.; Freitas, Antonio A.

    2011-01-01

    Globally, the 80's and 90's years were characterized by a significant reduction in the rate of growth of nuclear energy. However, from the 2000's, there has been a significant change in the international arena, with the 'renaissance' of interest in nuclear energy, even in countries that had abandoned nuclear power. To answer questions like security, reducing the generation of radioactive waste, control of proliferation risks and long-term sustainability, some initiatives have been adopted by some countries. In 2000, the Department of Energy - DOE - United States created the GIF - Generation IV International Forum for Nuclear Reactors. Six reactor concepts were selected based on criteria such as: reduction of radioactive wastes, safety and cost effective to meet the increasing energy demand on a sustainable basis, being resistant to diversion of materials for nuclear weapons proliferation and safer against terrorist attacks. In this context, it becomes important to use thorium as nuclear fuel for the Generation IV Advanced Reactors, with startup scheduled for 2030. Although the thorium does not present significant commercial value nowadays, in a not too distant future it will probably be an important commodity. Unfortunately, contrarily to what is happening in most developed countries in recent years, Brazil is paying little attention to the thorium, even less than in the past, despite its large reserves. Thorium is three to four times more abundant than uranium in the Earth's crust and, although not fissile, all thorium can be used to produce 233 U, by absorption of neutrons and subsequent radioactive decay. This uranium isotope is an excellent fuel for use in almost all types of nuclear reactors. It is possible that the thorium constitutes the largest Brazilian energy reserve, supplanting much oil (despite the findings of the pre-salt) and uranium. Brazil has a long tradition in the thorium technology, from mining of monazite until the obtainment of high purity

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

    International Nuclear Information System (INIS)

    1975-03-01

    The properties of rare earth elements as the material for control rods were studied. The rare earth elements, especially europium oxide, has the nuclear property corresponding to boron carbide, and its neutron absorption process does not emit alpha particles. The elements produced as a result of neutron capture also have large capture cross sections. This paper presents survey report on the properties and nuclear properties of rare earth elements, and comparison with other materials. Preliminary experiment was performed to make the pellets of europium oxide, and is described in this paper. Because of large density, the crystal form to be made was monoclinic system. Europium hydroxide was decomposed at 1000 0 C and 10 -5 torr. The obtained powder was dipped into benzene, and dryed in the air at 450 0 C. This powder was pressed and sintered in the air for one hour at 1500 0 C. The density of the obtained pellets was 97.0% of the theoretical density. The cross section of europium for fast neutron absorption is not yet accurately obtained, and is in the range between 4.65 and 8.5 barn for 151 Eu(n,γ) reaction. Since chain absorption reaction is caused in Eu, the overall capability of neutron absorption is not much changed by the loss of original material due to absorption. The pellets of europium oxide may be handled in air, but must be kept in dry atmosphere. The reactions of europium oxide with various metals were also investigated. The characteristic behavior in case of irradiation depends on the amount of silicon contained, and it was very good if the amount was less than 0.03%. (Kato, T.)

  9. Rare earth elements during diagenesis of abyssal sediments: analogies with a transuranic element americium

    International Nuclear Information System (INIS)

    Boust, D.

    1987-03-01

    One of the possibilities for the storage of high-level radioactive wastes consists in burying them into abyssal sediments, the sediments being supposed to barrier out radionuclides migration. The objective of the work was to estimate the efficiency of sediment barrier with respect to americium. As there is no americium in abyssal sediments, an indirect approach was used: the behaviour of the rare earth elements, the best natural analogs of americium. They were analysed in a 15 m long core, from the Cap Verde abyssal plateau. The terrigenous phase derived from the African continent was modified by short-term processes (1-1000 years); the intermediate rare earth elements were dissolved. Mineral coatings, enriched in rare earth appeared. After burial, the evolution continued at a much slower rate (10 5 - 10 6 years). The rare elements of the mineral coatings derived from the dissolution of the terrigenous phase and from an additional source, deeper in the sediment column. The fluxes of rare earth elements from sediment to water column were estimated. In suboxic sediments, the dissolved particulate equilibrium was related to redox conditions. The short-term reactivity of americium was studied in laboratory experiments. Simple americium migration models showed that the sediments barrier was totally efficient with respect to americium. In the conditions, neptunium 237 a daughter product of americium 241 could induce fluxes of 10 16 atoms per year per ton of stored waste (10 -8 Ci y-1), during millions years, towards the water column [fr

  10. China’s Rare Earth Elements Industry: What Can the West Learn?

    Science.gov (United States)

    2010-03-01

    of rare earth elements and on the research of rare earth metallurgy, environmental protection , new rare earth functional materials, and rare earth...scratches and other imperfections from the surface of the glass. Many glass (i.e.: eyeglasses , TV glass plates, plus most optical objects and...Fight to Protect Tungsten, Antimony, and Rare Earth Elements,” Chinese Government Net, May 7, 2009. 31 “China Mulls Plans to Curb Rare Earth Smuggling

  11. Chalcogenides formed by trivalent rare earth elements with d-elements

    International Nuclear Information System (INIS)

    Flao, Zh.; Laruehl', P.; Olitro, R.

    1981-01-01

    Data on ternary compounds formed by trivalent rare earth elements with 3d-, 4d- and 5d-elements of the Periodic system is presented. Compounds of 3d-elements both in bivalent and trivalent states are considered. The main attention is paid to the structure of the compounds. Description of a great number of new structural types of compounds is given. In certain cases the structure has not been deciphered and, besides, structural investigations with monocrystals are not numerous. Attention is drawn to the existence of nonstoichiometric compounds. References to the works on investigation of thermal (melting temperature), magnetic, optical and electric properties as well as Moessbauer effect are presented

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

    Science.gov (United States)

    Santoro, A; Thoss, V; Ribeiro Guevara, S; 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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 the tree

  14. Rare earth element and rare metal inventory of central Asia

    Science.gov (United States)

    Mihalasky, Mark J.; Tucker, Robert D.; Renaud, Karine; Verstraeten, Ingrid M.

    2018-03-06

    Rare earth elements (REE), with their unique physical and chemical properties, are an essential part of modern living. REE have enabled development and manufacture of high-performance materials, processes, and electronic technologies commonly used today in computing and communications, clean energy and transportation, medical treatment and health care, glass and ceramics, aerospace and defense, and metallurgy and chemical refining. Central Asia is an emerging REE and rare metals (RM) producing region. A newly compiled inventory of REE-RM-bearing mineral occurrences and delineation of areas-of-interest indicate this region may have considerable undiscovered resources.

  15. Ternary phosphates of rubidium-cesium-rare earth element

    International Nuclear Information System (INIS)

    Mel'nikov, P.P.; Carrillo-Eredero, H.D.; Efremov, V.A.; Komissarova, L.N.; Quiroga, E.

    1986-01-01

    This article examines the possibility of the existence of ternary phosphates of the rare earth elements (REE) containing two large alkali cations in order to establish the morphological and physicochemical characteristics in the entire group of ternary REE phosphates. The synthesis of the ternary rubidium-cesium-REE phosphates was carried out with molten charges that did not contain an excess of components. Analysis for the uncommon alkali cations was done by the atomic absorption technique; for holmium, by complexometric titration; and for phosphorus, by gravimetry as NH 4 CdPO 4 . The data obtained fully confirm the composition of Rb 2 CsLn(PO 4 ) 2

  16. Study on speciation of rare earth elements in soil

    International Nuclear Information System (INIS)

    Wang Yuqi; Sun Jingxin; Chen Hongmin; Guo Fanqing; Wang Lijun; Zhang Shen

    1996-01-01

    The contents of rare earth elements (REE) in red soil, yellow brown soil and leached chernozem are studied. After extracted sequentially, REE in these soils are fractionated into seven forms, i.e., (I) water soluble, (II) exchangeable, (III) loosely bound to organic mater, (IV) bound to carbonate and specifically absorbed, (V) bound to Fe-Mn oxides, (VI) tightly bound to organic matter and (VII) residual forms. The contents of REE in every form are determined by NAA (neutron activation analysis). The results show that REE in soils mainly exist in residual form and REE in soluble forms are very limited (<7%)

  17. Rare-earth elements in recent calcareous benthic organisms

    International Nuclear Information System (INIS)

    Roelandis, I.; Monty, C.L.V.

    1986-01-01

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

  18. Rare-earth elements in recent calcareous benthic organisms

    International Nuclear Information System (INIS)

    Roelandts, I.; Monty, C.L.V.

    1987-01-01

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

  19. Rare earth element abundances in presolar SiC

    Science.gov (United States)

    Ireland, T. R.; Ávila, J. N.; Lugaro, M.; Cristallo, S.; Holden, P.; Lanc, P.; Nittler, L.; Alexander, C. M. O'D.; Gyngard, F.; Amari, S.

    2018-01-01

    Individual isotope abundances of Ba, lanthanides of the rare earth element (REE) group, and Hf have been determined in bulk samples of fine-grained silicon carbide (SiC) from the Murchison CM2 chondrite. The analytical protocol involved secondary ion mass spectrometry with combined high mass resolution and energy filtering to exclude REE oxide isobars and Si-C-O clusters from the peaks of interest. Relative sensitivity factors were determined through analysis of NIST SRM reference glasses (610 and 612) as well as a trace-element enriched SiC ceramic. When normalised to chondrite abundances, the presolar SiC REE pattern shows significant deficits at Eu and Yb, which are the most volatile of the REE. The pattern is very similar to that observed for Group III refractory inclusions. The SiC abundances were also normalised to s-process model predictions for the envelope compositions of low-mass (1.5-3 M⊙) AGB stars with close-to-solar metallicities (Z = 0.014 and 0.02). The overall trace element abundances (excluding Eu and Yb) appear consistent with the predicted s-process patterns. The depletions of Eu and Yb suggest that these elements remained in the gas phase during the condensation of SiC. The lack of depletion in some other moderately refractory elements (like Ba), and the presence of volatile elements (e.g. Xe) indicates that these elements were incorporated into SiC by other mechanisms, most likely ion implantation.

  20. Exploring the limits of EDS microanalysis: rare earth element analyses

    Science.gov (United States)

    Ritchie, N. W. M.; Newbury, D. E.; Lowers, H.; Mengason, M.

    2018-01-01

    It is a great time to be a microanalyst. After a few decades of incremental progress in energy-dispersive X-ray spectrometry (EDS), the last decade has seen the accuracy and precision surge forward. Today, the question is not whether EDS is generally useful but to identify the types of problems for which wavelength-dispersive X-ray spectrometry remains the better choice. The full extent of EDS’s capabilities has surprised many. Low Z, low energy, and trace element detection have been demonstrated even in the presence of extreme peak interferences. In this paper, we will summarise the state-of-the-art and investigate a challenging problem domain, the analysis of minerals bearing multiple rare-earth elements.

  1. Analysis of the effects of stirring condition of separation of thorium in the elution process of monazite partial solution by solvent impregnated resin method

    Science.gov (United States)

    Prassanti, R.; Putra, D. S.; Kusuma, B. P.; Nawawi, F. W.

    2018-01-01

    Monazite is a natural mineral which contains abundant valuable element such as Radioactive Element and Rare Earth Element(REE). In this experiment, it is proven that solution of residual Thorium Sulfate from Monazite mineral process, can be seperated selectively by using extracting method of Solvent Impregnated Resin(SIR), with the elutant solution HNO3. In the earlier process, Thorium solution is conditioned at PH 1 by using H2SO4. Then REE, Thorium and Uranium elements are seperated. This seperation is conducted by using adsorption method by Amberlite XAD-16 Resin, which has been impregnated by Tributhyl Phosphate extractant. It is continued with elution process, which is aimed to obtain Thorium solution of a higher level of concentration. This elution process is conducted by using HNO3, with the elution variables of the lenght of mixing and amount concentration elutant. Based on this experiment, SIR extracting method is able to dissolve Thorium solution until 63,2%grade and a higher level of %grade about 92,40%. It can be concluded that this SIR method can extracted Thorium elements selectively, improve extracting process recovery, and determine optimum stripping condition in the 45th minutes with elutant concentration of 1,0M HNO3.

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

    Directory of Open Access Journals (Sweden)

    Pierre Gueriau

    Full Text Available 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  5. RARE EARTH ELEMENT IMPACTS ON BIOLOGICAL WASTEWATER TREATMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Y.; Barnes, J.; Fox, S.

    2016-09-01

    Increasing demand for rare earth elements (REE) is expected to lead to new development and expansion in industries processing and or recycling REE. For some industrial operators, sending aqueous waste streams to a municipal wastewater treatment plant, or publicly owned treatment works (POTW), may be a cost effective disposal option. However, wastewaters that adversely affect the performance of biological wastewater treatment at the POTW will not be accepted. The objective of our research is to assess the effects of wastewaters that might be generated by new rare earth element (REE) beneficiation or recycling processes on biological wastewater treatment systems. We have been investigating the impact of yttrium and europium on the biological activity of activated sludge collected from an operating municipal wastewater treatment plant. We have also examined the effect of an organic complexant that is commonly used in REE extraction and separations; similar compounds may be a component of newly developed REE recycling processes. Our preliminary results indicate that in the presence of Eu, respiration rates for the activated sludge decrease relative to the no-Eu controls, at Eu concentrations ranging from <10 to 660 µM. Yttrium appears to inhibit respiration as well, although negative impacts have been observed only at the highest Y amendment level tested (660 µM). The organic complexant appears to have a negative impact on activated sludge activity as well, although results are variable. Ultimately the intent of this research is to help REE industries to develop environmentally friendly and economically sustainable beneficiation and recycling processes.

  6. Bacterial Cell Surface Adsorption of Rare Earth Elements

    Science.gov (United States)

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

    Science.gov (United States)

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

    2012-03-01

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

  8. Rare earth elements as a by-catch of sedimentary deposits. Exploration program of rare earth elements; Selten Erd Elemente als Beifang sedimentaerer Lagerstaetten. Erkundungsprogramm Selten Erd Elemente

    Energy Technology Data Exchange (ETDEWEB)

    Linhardt, E.; Gebhardt, A. (comps.)

    2014-02-15

    The increasing demand for rare earth elements (REE) in the field of ''green technologies'' on the one hand and the shortage of raw materials on the world markets on the other hand confronted also Bavaria as an industrial location with growing supply problems in these ''high tech raw materials''. The aim of exploration was the clarification of the feedstock REE potential of heavy mineral concentrates which are obtained in the industrial extraction and processing of sand and kaolin in existing extraction operations in northern Bavaria as by catch and are potentially winnable or marketable. The in-depth investigation enabled the potential of found rare earth elements and other high-tech metal oxides that can be classified as very likely find it in terms of an economic recovery. [German] Der zunehmende Bedarf an Selten Erd Elementen (SEE) im Bereich der ''Gruenen Technologien'' zum Einen sowie die Rohstoffverknappung auf den Weltmaerkten zum Anderen konfrontiert auch Bayern als Industriestandort mit wachsenden Versorgungsproblemen bei diesen ''high tech-Grundstoffen''. Ziel der Erkundung war die Klaerung des rohstofflichen SEE-Potenzials von Schwermineralkonzentraten, die bei der grosstechnischen Gewinnung und Aufbereitung von Sand und Kaolin in vorhandenen Gewinnungsbetrieben Nordbayerns als Beifang anfallen und potenziell gewinn- bzw. vermarktbar sind. Im Zuge der Untersuchung konnten nutzbare Potenziale von Selten Erd Elementen und anderen high-tech - Metalloxiden gefunden werden, die sehr wahrscheinlich als fuendig im Hinblick auf eine wirtschaftliche Gewinnung eingestuft werden koennen.

  9. Use of thorium in the generation IV Molten Salt reactors and perspectives for Brazil

    International Nuclear Information System (INIS)

    Seneda, Jose A.; Lainetti, Paulo E.O.

    2013-01-01

    Interest in thorium stems mainly from the fact that it is expected a substantial increase in uranium prices over the next fifty years. The reactors currently in operation consume 65,500 tons of uranium per year. Each electrical gigawatt (GWe) additional need about 200 tU mined per year. So advanced fuel cycles, which increase the reserves of nuclear materials are interesting, particularly the use of thorium to produce the fissile isotope 233 U. It is important to mention some thorium advantages. Thorium is three to five times more abundant than uranium in the earth's crust. Thorium has only one oxidation state. Additionally, thoria produces less radiotoxicity than the UO 2 because it produces fewer amounts of actinides, reducing the radiotoxicity of long life nuclear waste. ThO 2 has higher corrosion resistance than UO 2 , besides being chemically stable due to their low water solubility. The burning of Pu in a reactor based in thorium also decreases the inventories of Pu from the current fuel cycles, resulting in lower risks of material diversion for use in nuclear weapons. There are some ongoing projects in the world, taking into consideration the proposed goals for Generation IV reactors, namely: sustainability, economics, safety and reliability, proliferation resistance and physical protection. Some developments on the use of thorium in reactors are underway, with the support of the IAEA and some governs. Can be highlighted some reactor concepts using thorium as fuel: CANDU; ADTR -Accelerator Driven Thorium Reactor; AHWR -Advanced Heavy Water Reactor proposed by India (light water cooled and moderated by heavy water) and the MSR -Molten Salt Reactor. The latter is based on a reactor concept that has already been successfully tested in the U.S. in the 50s, for use in aircrafts. In this paper, we discuss the future importance of thorium, particularly for Brazil, which has large mineral reserves of this strategic element, the characteristics of the molten salt

  10. Process for the total recovery of uranium, yttrium, thorium and rare earths contained in an organic phase

    International Nuclear Information System (INIS)

    Rollat, A.; Sabot, J.L.

    1984-01-01

    In this process the organic phase, obtained by solvent extraction, is contacted with a miscible solvent (at least partially) and a precipitating agent. A liquid phase and a precipitate containing U, Y, Th and R.E. are obtained. The process can be used for recovering these elements from wet process phosphoric acid [fr

  11. Thorium fueled reactor

    Science.gov (United States)

    Sipaun, S.

    2017-01-01

    Current development in thorium fueled reactors shows that they can be designed to operate in the fast or thermal spectrum. The thorium/uranium fuel cycle converts fertile thorium-232 into fissile uranium-233, which fissions and releases energy. This paper analyses the characteristics of thorium fueled reactors and discusses the thermal reactor option. It is found that thorium fuel can be utilized in molten salt reactors through many configurations and designs. A balanced assessment on the feasibility of adopting one reactor technology versus another could lead to optimized benefits of having thorium resource.

  12. Addressing Criticality in Rare Earth Elements via Permanent Magnets Recycling

    Science.gov (United States)

    Nlebedim, I. C.; King, A. H.

    2018-02-01

    Rare earth elements (REEs) are critical for many advanced technologies and are faced with potential supply disruptions. Recycling of permanent magnets (PMs) can be good sources for REEs which can help minimize global dependence on freshly mined REEs, but PMs are rarely recycled. Recycling of PMs has been discussed with respect to improving REEs resource sustainability. Some challenges to be addressed in order to establish industrially deployable technologies for PMs recycling have also been discussed, including profitability, energy efficiency and environmental impacts. Key considerations for promoting circular economy via PMs recycling is proposed with the focus on deciding the target points in the supply chain at which the recycled products will be inserted. Important technical considerations for recycling different forms of waste PMs, including swarfs, slags, shredded and intact hard disk drives magnets, have been presented. The aspects of circular economy considered include reusing magnets, remanufacturing magnets and recovering of REEs from waste PMs.

  13. Reaction cross section calculation of some alkaline earth elements

    Science.gov (United States)

    Tel, Eyyup; Kavun, Yusuf; Sarpün, Ismail Hakki

    2017-09-01

    Reaction cross section knowledge is crucial to application nuclear physics such as medical imaging, radiation shielding and material evaluations. Nuclear reaction codes can be used if the experimental data are unavailable or are improbably to be produced because of the experimental trouble. In this study, there action cross sections of some target alkaline earth elements have been calculated by using pre-equilibrium and equilibrium nuclear reaction models for nucleon induced reactions. While these calculations, the Hybrid Model, the Geometry Dependent Hybrid Model, the Full Exciton Model, the Cascade Exciton Model for pre-equilibrium reactions and the Weisskopf-Ewing Model for equilibrium reactions have been used. The calculated cross sections have been discussed and compared with the experimental data taken from Experimental Nuclear Reaction Data library.

  14. Active earth pressure model tests versus finite element analysis

    Directory of Open Access Journals (Sweden)

    Pietrzak Magdalena

    2017-01-01

    Full Text Available The purpose of the paper is to compare failure mechanisms observed in small scale model tests on granular sample in active state, and simulated by finite element method (FEM using Plaxis 2D software. Small scale model tests were performed on rectangular granular sample retained by a rigid wall. Deformation of the sample resulted from simple wall translation in the direction ‘from the soil” (active earth pressure state. Simple Coulomb-Mohr model for soil can be helpful in interpreting experimental findings in case of granular materials. It was found that the general alignment of strain localization pattern (failure mechanism may belong to macro scale features and be dominated by a test boundary conditions rather than the nature of the granular sample.

  15. Active earth pressure model tests versus finite element analysis

    Science.gov (United States)

    Pietrzak, Magdalena

    2017-06-01

    The purpose of the paper is to compare failure mechanisms observed in small scale model tests on granular sample in active state, and simulated by finite element method (FEM) using Plaxis 2D software. Small scale model tests were performed on rectangular granular sample retained by a rigid wall. Deformation of the sample resulted from simple wall translation in the direction `from the soil" (active earth pressure state. Simple Coulomb-Mohr model for soil can be helpful in interpreting experimental findings in case of granular materials. It was found that the general alignment of strain localization pattern (failure mechanism) may belong to macro scale features and be dominated by a test boundary conditions rather than the nature of the granular sample.

  16. Determination of rare earth elements in biomonitors by neutron activation

    International Nuclear Information System (INIS)

    Figueiredo, Ana M.G.; Saiki, Mitiko; Ticianelli, R.B.; Domingos, M.; Alves, E.S.; Marcelli, M.P.

    2000-01-01

    The rare earth elements (REE) are becoming more and more important from the technological point of view, due to their increasing use in modern industry. Due to this fact, environmental contamination by REE may become significant, and little information are still available about biological effects of REE in plants, animals and human beings. The use of biomonitors to control environmental pollution has been an ecological and economical alternative in Europe and United Sates, to minimize the high costs of conventional equipment s. In the present paper, neutron activation analysis was employed to determine La, Ce, Nd, Sm, Eu, Tb, Yb and Lu in the lichen Canoparmelia texana and in Tillandsia usneoides, species that have been widely used as monitors of atmospheric pollution. The results showed an accumulation of REE in the biomonitors, indicating good possibilities of their utilization in the study of environmental contamination by REE. (author)

  17. Geochemistry of Thorium and Uranium in Soils of the Southern Urals

    Science.gov (United States)

    Asylbaev, I. G.; Khabirov, I. K.; Gabbasova, I. M.; Rafikov, B. V.; Lukmanov, N. A.

    2017-12-01

    Specific features of the horizontal and vertical distribution of uranium and thorium in soils and parent materials of the Southern Urals within the Bashkortostan Republic have been studied with the use of mass spectrometry with inductively coupled plasma. The dependence of distribution patterns of these elements on the local environmental conditions is shown. A scale for soil evaluation according to the concentrations of uranium and thorium (mg/kg) is suggested: the low level, up to 3; medium, up to 9; high, up to 15; and very high, above 15 mg/kg. On the basis of to this scale, the ecological state of the soils is evaluated, and the schematic geochemical map of the region is compiled. The territory of Bashkortostan is subdivided into two parts according to the contents of radioactive elements in soils: the western part with distinct accumulation of uranium and the eastern part with predominant thorium accumulation. This finding supports the charriage (thrust fault) nature of the fault zone of the Southern Urals. The vertical distribution patterns of uranium and thorium in soils of the region are of the same character. The dependence between the contents of these two elements and rare-earth elements has been established. The results of this study are applied for assessing the ecological state of soils in the region.

  18. Rare Earth elements in individual minerals in Shergottites

    Science.gov (United States)

    Wadhwa, Meenakshi; Crozaz, Ghislaine

    1993-01-01

    Shergottites (i.e., Shergotty, Zagami, EETA79001, ALHA77005, and LEW88516) are an important set of achondrites because they comprise the majority of the SNC group of meteorites (nine, in total, known to us), which are likely to be samples of the planet Mars. Study of these meteorites may therefore provide valuable information about petrogenetic processes on a large planetary body other than Earth. Rare earth element (REE) distributions between various mineral phases were found to be useful in geochemically modeling the petrogenesis of various rock types (terrestrial and meteoritic). However, with the exception of a few ion microprobe studies and analyses of mineral separates, there has previously not been any comprehensive effort to characterize and directly compare REE in individual minerals in each of the five known shergottites. Ion microprobe analyses were made on thin sections of each of the shergottites. Minerals analyzed were pyroxenes (pigeonite and augite), maskelynite, and whitlockite. The REE concentrations in each mineral type in each shergottite is given.

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

    Science.gov (United States)

    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.

  20. Radionuclide Basics: Thorium

    Science.gov (United States)

    Thorium is a naturally occurring radioactive metal found at trace levels in soil, rocks, plants and animals. Thorium is used very little in industry, but can be found in heat-resistant alloys and paints and optical lenses.

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

    International Nuclear Information System (INIS)

    Kitto, M.E.; Gordon, G.E.; Anderson, D.L.; Olmez, I.

    1991-01-01

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

  2. Health risk assessment of rare earth elements in cereals from mining area in Shandong, China.

    Science.gov (United States)

    Zhuang, Maoqiang; Wang, Liansen; Wu, Guangjian; Wang, Kebo; Jiang, Xiaofeng; Liu, Taibin; Xiao, Peirui; Yu, Lianlong; Jiang, Ying; Song, Jian; Zhang, Junli; Zhou, Jingyang; Zhao, Jinshan; Chu, Zunhua

    2017-08-29

    To investigate the concentrations of rare earth elements in cereals and assess human health risk through cereal consumption, a total of 327 cereal samples were collected from rare earth mining area and control area in Shandong, China. The contents of 14 rare earth elements were determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The medians of total rare earth elements in cereals from mining and control areas were 74.22 μg/kg and 47.83 μg/kg, respectively, and the difference was statistically significant (P rare earth elements concentrations (109.39 μg/kg and 77.96 μg/kg for mining and control areas, respectively) and maize had the lowest rare earth elements concentrations (42.88 μg/kg and 30.25 μg/kg for mining and control areas, respectively). The rare earth elements distribution patterns for both areas were characterized by enrichment of light rare earth elements. The health risk assessment demonstrated that the estimated daily intakes of rare earth elements through cereal consumption were considerably lower than the acceptable daily intake (70 μg/kg bw). The damage to adults can be neglected, but more attention should be paid to the effects of continuous exposure to rare earth elements on children.

  3. Advanced Characterization of Rare Earth Elements in Coal Utilization Byproducts

    Science.gov (United States)

    Verba, C.; Scott, M.; Dieterich, M.; Poston, J.; Collins, K.

    2016-12-01

    Rare earth elements (REE) in various forms (e.g., crystalline mineral phases; adsorbed/absorbed state on and into organic macerals, neoformed glass from flyash or bottom ash) from domestic feedstocks such as coal deposits to coal utilization byproducts (CUB) have the potential to reduce foreign REE dependence and increase domestic resource security. Characterization is critical for understanding environmental risks related to their fate and transport as well as determining the most practical and economical techniques for concentrating the REE and converting them into chemical stocks for manufacturing. Several complementary electron microscopy (SEM-EDS, EPMA-WDS, FIB-SEM, cathodoluminescence, and XRD) and post image processing techniques were used to understand REE transition from coal to CUB. Sites of interest were identified and imaged and respective elemental x-ray maps acquired and montaged. Pixel classification of SEM imagers was completed using image analysis techniques to quantify the distribution of REE associated features. Quantitative elemental analysis of phases were completed using EMPA-WDS followed by FIB-SEM. The FIB-SEM results were reconstructed into 3D volumes and features of interest (e.g. monazite) were analyzed to determine the structure and volumetric estimation of REEs and thus predict detrital REE phases to ICP-MS results. Trace minerals were identified as pyrite, zircon, REE-phosphates' (monazite, xenotime), and barite within the coal tailings. In CUB, amorphous aluminosilicates, iron oxide cenospheres, and calcium oxides were present; monazite appear to be unaltered and unaffected by the combustion process in these samples. Thermal decomposition may have occurred due to presence of detrital zircon and xenotime and subsequent thin Ca-oxide coating enriched in trace REEs.

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

    International Nuclear Information System (INIS)

    Otero, N.; Vitoria, L.; Soler, A.; Canals, A.

    2005-01-01

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

  5. Analytical application of poly [dibenzo-18-crown-6] for chromatographic separation of thorium(IV) from uranium(VI) and other elements in glycine medium

    International Nuclear Information System (INIS)

    Kadam, R.B.; Mali, G.G.; Mohite, B.S.

    2013-01-01

    A selective and effective chromatographic separation method for thorium(IV) has been developed by using poly [dibenzo-18-crown-6] as stationary phase. The separations are carried out from glycine medium. The sorption of thorium(IV) was quantitative from 1 x 10 -2 to 1 x 10 -4 M glycine. The elution of thorium(IV) was quantitative with 2.0-8.0 M HCl, 4.0-7.0 HBr, 1.0-2.0 M HClO 4 and 5.0 M H 2 SO 4 . The capacity of poly [dibenzo-18-crown-6] for thorium(IV) was found to be 0.215 ± 0.01 mmol/g of crown polymer. The effect of concentration of glycine, metal ion, foreign ion and eluents has been studied. Thorium(IV) was separated from a number of cations in ternary as well as in multicomponent mixtures. The applicability of the proposed method was checked for the determination of thorium(IV) in real as well as geological sample. The method is simple, rapid, and selective with good reproducibility (approximately ±2 %). (author)

  6. [Physiological effects of rare earth elements and their application in traditional Chinese medicine].

    Science.gov (United States)

    Zhou, Jie; Guo, Lanping; Xiao, Wenjuan; Geng, Yanling; Wang, Xiao; Shi, Xin'gang; Dan, Staerk

    2012-08-01

    The process in the studies on physiological effects of rare earth elements in plants and their action mechanisms were summarized in the aspects of seed germination, photosynthesis, mineral metabolism and stress resistance. And the applications of rare earth elements in traditional Chinese medicine (TCM) in recent years were also overviewed, which will provide reference for further development and application of rare earth elements in TCM.

  7. The utilization of thorium in light water reactors - a comparison between a PWR fuel element using UO2 with a seed blanket fuel element using (Th-U)O2

    International Nuclear Information System (INIS)

    Fernandes, Ana C.A.A.; Maiorino, Jose R.; Carluccio, Thiago; Russo, Pedro C.R.

    2011-01-01

    In this work a preliminary study on the utilization of thorium in light water reactor is made. The work compares the performance of a typical PWR fuel element, 17X17, Pitch = 1.43 cm, using UO 2 , 3 w/0 enriched(reference) with one seed blanket fuel element, consisting of the (Th 0.9 U 0.1 ) O 2 in the blanket, and UO 2 in the seed, with 20 w/0 of uranium enrichment and the same reference pitch. The parameters of the comparison were, 1) the production of Plutonium, minor actinides (MA) and long lived fission products(LLFP) after 300 days of burn up in order to assess the radio toxicity of these two fuel elements, 2) the conversion ratio, 3) k eff versus time. All the calculations were made using TRITON/NEWT modules of SCALE 5.1, with a library 238groupndf from ENDFB-VI. The results shows that the seed-blanket (Th-U)O 2 produces less plutonium, MA and LLPP than the reference fuel element, demonstrating that it has a lower radio toxicity and therefore more attractive for spent fuel storage. Also the neutronic performance shows advantages for the (Th-U)O 2 . (author)

  8. Determination of the total nitrate content of thorium nitrate solution with a selective electrode

    International Nuclear Information System (INIS)

    Wirkner, F.M.

    1979-01-01

    The nitrate content of thorium nitrate solutions is determined with a liquid membrane nitrate selective electrode utilizing the known addition method in 0.1 M potassium fluoride medium as ionic strength adjustor. It is studied the influence of pH and the presence of chloride, sulphate, phosphate, meta-silicate, thorium, rare earths, iron, titanium, uranium and zirconium at the same concentrations as for the aqueous feed solutions in the thorium purification process. The method is tested in synthetic samples and in samples proceeding from nitric dissolutions of thorium hidroxide and thorium oxicarbonate utilized as thorium concentrates to be purified [pt

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

    Science.gov (United States)

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

    2016-01-01

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

  10. Geochemical prospecting for rare earth elements using termite mound materials

    Science.gov (United States)

    Horiuchi, Yu; Ohno, Tetsuji; Hoshino, Mihoko; Shin, Ki-Cheol; Murakami, Hiroyasu; Tsunematsu, Maiko; Watanabe, Yasushi

    2014-12-01

    The Blockspruit fluorite prospect, located in North West State of the Republic of South Africa, occurs within an actinolite rock zone that was emplaced into the Kenkelbos-type granite of Proterozoic age. There are a large number of termite mounds in the prospect. For geochemical prospecting for rare earth elements (REEs), in total, 200 samples of termite mound material were collected from actinolite rock and granite zones in the prospect. Geochemical analyses of these termite mound materials were conducted by two methods: portable X-ray fluorescence (XRF) spectrometry and inductively coupled plasma-mass spectrometry (ICP-MS). Comparison of the two methods broadly indicates positive correlations of REEs (La, Ce, Pr, Nd, and Y), in particular Y and La having a strong correlation. As the result of modal abundance analyses, the actinolite rock at surface mainly consists of ferro-actinolite (89.89 wt%) and includes xenotime (0.26 wt%) and monazite (0.21 wt%) grains as REE minerals. Termite mound materials from actinolite rock also contain xenotime (0.27 wt%) and monazite (0.41 wt%) grains. In addition, termite mound materials from the actinolite rock zone have high hematite and Fe silicate contents compared to those from granite zone. These relationships suggest that REE minerals in termite mound materials originate form actinolite rock. Geochemical anomaly maps of Y, La, and Fe concentrations drawn based on the result of the portable XRF analyses show that high concentrations of these elements trend from SW to NE which broadly correspond to occurrences of actinolite body. These results indicate that termite mounds are an effective tool for REE geochemical prospection in the study area for both light REEs and Y, but a more detailed survey is required to establish the distribution of the actinolite rock body.

  11. Rare earth elements in some bottled waters of Serbia

    Directory of Open Access Journals (Sweden)

    Todorović Maja

    2013-01-01

    Full Text Available Twenty-one bottled mineral and spring waters from Serbia were analyzed for 16 inorganic chemical parameters, including lanthanides and yttrium which belong to the group of so-called rare earth elements (REE. REE concentrations in the bottled water samples varied over a broad range, from 5.39 to 1585.82 ng/L. Total concentrations in the bottled water samples were calculated taking into account the classification of lanthanides into heavy (HREE and light (LREE, with yttrium added to the HREE group. The LREE concentrations ranged from 3.62 to 1449.63 ng/L, while those of the HREE were from 0 to 136.19 ng/L. Distinct REE signatures were observed in waters that drained specific rocks. The REE patterns in groundwater from granitic and related rocks showed LREE and HREE enrichment, while groundwater with mafic rock influence exhibited slightly LREE enrichment. Several bottled water samples featured naturally-occurring carbon dioxide, whose solutional capacity contributed to the highest REE concentrations in the analyzed samples. High REE concentrations are also a result of sudden changes in oxidation-reduction conditions, which particularly affect La, Ce and Eu. Aquifers developed in granitic and related rocks (methamorphic and sedimentary rocks constitute favorable environments for HREE in groundwater, corroborated by the occurrence of HREE in bottled water samples. The bottled water samples largely exhibited a negative cerium anomaly and nearly all the samples showed a positive europium anomaly.

  12. Rare earth elements in the Pacific and Atlantic Oceans

    International Nuclear Information System (INIS)

    Baar, H.J.W. de; Bacon, M.P.; Brewer, P.G.; Bruland, K.W.

    1985-01-01

    The first profiles of Pr, Tb, Ho, Tm and Lu in the Pacific Ocean, as well as profiles of La, Ce, Nd, Sm, Eu, Gd and Yb are reported. Concentrations of REE (except Ce) in the deep water are two to three times higher than those observed in the deep Atlantic Ocean. Surface water concentrations are typically lower than in the Atlantic Ocean, especially for the heavier elements Ho,Tm,Yb and Lu. Cerium is strongly depleted in the Pacific water column, but less so in the oxygen minimum zone. The distribution of the REE group is consistent with two simultaneous processes: (1) cycling similar to that of opal and calcium carbonate, and (2) adsorptive scavenging by settling particles and possibly by uptake at ocean boundaries. However, the first process can probably not be sustained by the low REE contents of shells, unless additional adsorption on surfaces is invoked. The second process, adsorptive scavenging, largely controls the oceanic distribution and typical seawater pattern of the rare earths. (author)

  13. MICROBIALLY MEDIATED LEACHING OF RARE EARTH ELEMENTS FROM RECYCLABLE MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-01

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

  14. Continental shelves as potential resource of rare earth elements.

    Science.gov (United States)

    Pourret, Olivier; Tuduri, Johann

    2017-07-19

    The results of this study allow the reassessment of the rare earth elements (REE) external cycle. Indeed, the river input to the oceans has relatively flat REE patterns without cerium (Ce) anomalies, whereas oceanic REE patterns exhibit strong negative Ce anomalies and heavy REE enrichment. Indeed, the processes at the origin of seawater REE patterns are commonly thought to occur within the ocean masses themselves. However, the results from the present study illustrate that seawater-like REE patterns already occur in the truly dissolved pool of river input. This leads us to favor a partial or complete removal of the colloidal REE pool during estuarine mixing by coagulation, as previously shown for dissolved humic acids and iron. In this latter case, REE fractionation occurs because colloidal and truly dissolved pools have different REE patterns. Thus, the REE patterns of seawater could be the combination of both intra-oceanic and riverine processes. In this study, we show that the Atlantic continental shelves could be considered potential REE traps, suggesting further that shelf sediments could potentially become a resource for REE, similar to metalliferous deep sea sediments.

  15. Size distribution of rare earth elements in coal ash

    Science.gov (United States)

    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. 

  16. REGENERATION OF FISSION-PRODUCT-CONTAINING MAGNESIUM-THORIUM ALLOYS

    Science.gov (United States)

    Chiotti, P.

    1964-02-01

    A process of regenerating a magnesium-thorium alloy contaminated with fission products, protactinium, and uranium is presented. A molten mixture of KCl--LiCl-MgCl/sub 2/ is added to the molten alloy whereby the alkali, alkaline parth, and rare earth fission products (including yttrium) and some of the thorium and uranium are chlorinated and

  17. Assessment of Thorium Analysis Methods

    International Nuclear Information System (INIS)

    Putra, Sugili

    1994-01-01

    The Assessment of thorium analytical methods for mixture power fuel consisting of titrimetry, X-ray flouresence spectrometry, UV-VIS spectrometry, alpha spectrometry, emission spectrography, polarography, chromatography (HPLC) and neutron activation were carried out. It can be concluded that analytical methods which have high accuracy (deviation standard < 3%) were; titrimetry neutron activation analysis and UV-VIS spectrometry; whereas with low accuracy method (deviation standard 3-10%) were; alpha spectrometry and emission spectrography. Ore samples can be analyzed by X-ray flourescnce spectrometry, neutron activation analysis, UV-VIS spectrometry, emission spectrography, chromatography and alpha spectometry. Concentrated samples can be analyzed by X-ray flourescence spectrometry; simulation samples can be analyzed by titrimetry, polarography and UV-VIS spectrometry, and samples of thorium as minor constituent can be analyzed by neutron activation analysis and alpha spectrometry. Thorium purity (impurities element in thorium samples) can be analyzed by emission spectography. Considering interference aspects, in general analytical methods without molecule reaction are better than those involving molecule reactions (author). 19 refs., 1 tabs

  18. Health status and body radioactivity of former thorium workers

    International Nuclear Information System (INIS)

    Stehney, A.F.; Polednak, A.P.; Rundo, J.; Brues, A.M.; Lucas, H.F. Jr.; Patten, B.C.; Rowland, R.E.

    1981-01-01

    The objectives of the study are: (1) to assess possible health effects of employment in the thorium milling industry by comparison of mortality and morbidity characteristics of former thorium workers with those of suitable general populations; (2) to examine disease outcomes by estimated exposure levels of thorium and thoron daughter products for possible radiation-related effects; and (3) to determine the body distribution of inhaled thorium (and daughters) and rare earths in humans by radioactivity measurements in vivo and by analysis of autopsy samples. The principal end points for investigation are respiratory disease and cancers of lung, liver, bone, and bone marrow

  19. First steps of integrated spatial modeling of titanium, zirconium, and rare earth element resources within the Coastal Plain sediments of the southeastern United States

    Science.gov (United States)

    Ellefsen, Karl J.; Van Gosen, Bradley S.; Fey, David L.; Budahn, James R.; Smith, Steven M.; Shah, Anjana K.

    2015-01-01

    The Coastal Plain of the southeastern United States has extensive, unconsolidated sedimentary deposits that are enriched in heavy minerals containing titanium, zirconium, and rare earth element resources. Areas favorable for exploration and development of these resources are being identified by geochemical data, which are supplemented with geological, geophysical, hydrological, and geographical data. The first steps of this analysis have been completed. The concentrations of lanthanum, yttrium, and titanium tend to decrease as distance from the Piedmont (which is the likely source of these resources) increases and are moderately correlated with airborne measurements of equivalent thorium concentration. The concentrations of lanthanum, yttrium, and titanium are relatively high in those watersheds that adjoin the Piedmont, south of the Cape Fear Arch. Although this relation suggests that the concentrations are related to the watersheds, it may be simply an independent regional trend. The concentration of zirconium is unrelated to the distance from the Piedmont, the equivalent thorium concentration, and the watershed. These findings establish a foundation for more sophisticated analyses using integrated spatial modeling.

  20. Preliminary Study of Development of the Organization of Rare-Earth Exportation Countries (OREEC

    Directory of Open Access Journals (Sweden)

    Takashi Kamei

    2013-03-01

    Full Text Available The largest two sectors emitting CO2 in the world are electricity generation and land-transportation. Therefore, nuclear power plays an important role in generating electricity with low CO2 emission. An important aspect needs to be considered to ensure environmental sustainability is nuclear non-proliferation and less amount of radioactive waste generated. Thus the use of "thorium" as nuclear fuel has received increasing interest because thorium produces little amount of plutonium and very little amount of long-lived minor actinide. However, thorium cannot be used immediately due to its lack of fissile isotope indispensable to start fission reaction. At the same time, electric vehicle and hybrid-vehicle become more popular as low-carbon automobiles. Rare-earth elements are indispensable for manufacturing these low-carbon automobiles. However the problem with rare-earth production is its radioactive by-product of "thorium". Since the largest potential of consuming thorium by nuclear power still needs several decades for commercializing, there becomes a discrepancy in consumption and production of thorium causing unused stockpile of thorium. Several countries have announced to supply rare-earth but this cannot be safely and economically done unless thorium problem is solved. In this paper, an international framework called the "OREEC: Organization of Rare-Earth Exportation Countries" is proposed as a solution to this issue. The OREEC has mainly three functions: (1 ThAX, which is a financial collecting method, (2 Th FREE label, which is certification of adequate treatment of thorium and (3 The Bank, which stores separated thorium.

  1. Prospective thorium fuels for future nuclear energy generation

    International Nuclear Information System (INIS)

    Lainetti, Paulo E.O.

    2017-01-01

    In the beginning of the Nuclear Era, many countries were interested on thorium, particularly during the 1950 1970 periods. Nevertheless, since its discovery almost two centuries ago, the use of thorium has been restricted to gas mantles employed in gas lighting. The future world energy needs will increase and, even if we assumed a conservative contribution of nuclear generation, it will be occur a significant increasing in the uranium prices, taking into account that uranium, as used in the present thermal reactors, is a finite resource. Nowadays approximately the worldwide yearly requirement of uranium for about 435 nuclear reactors in operation is 65,000 metric t. Therefore, alternative solutions for future must be developed. Thorium is nearly three times more abundant than uranium in The Earth's crust. Despite thorium is not a fissile material, 232 Th can be converted to 233 U (fissile) more efficiently than 238 U to 239 Pu. Besides this, thorium is an environment alternative energy source and also inherently resistant to proliferation.. Many countries had initiated research on thorium in the past, Nevertheless, the interest evanesced due new uranium resources discoveries and availability of enriched uranium at low prices from obsolete weapons. Some papers evaluate the thorium resources in Brazil over 1.200.000 metric t. Then, the thorium alternative must be seriously considered in Brazil for strategic reasons. A brief history of thorium and its utilization are presented, besides a very short discussion about prospective thorium nuclear fuels for the next generation of nuclear reactors. (author)

  2. Separation process of heavy rare earth elements from xenotime ore

    International Nuclear Information System (INIS)

    Sri Sukmajaya; Tri Handini; Wahyu Rachmi Pusparini; Dwi Biyantoro

    2016-01-01

    Separation process of heavy rare earth elements from xenotime ore had been done. A 100 mesh of xenotime ore was upgrade using water, sodium silicate and oleic acid in pH 9. Mixed of slurry by air blown in room temperature along 30 minutes. The middle of slurry xenotime was be separated, then dried and so added soda caustic, potassium carbonate and ammonium dihydrogen phosphate. The mix was be homogenized then leached in furnace to 700°C temperature along 4 hours. The frits of leaching product would be leached using 1200 mL volume of water that made oxidation by HCl onto pH 4 by agitated heated in 70°C temperature. The mix was filtered, then solid settled was be dried and then to processed again in water HCl acidified leaching alike before until pH 4 with minimized HCl added least 2 mL. The solid settled filled into 1000 mL of beker glass, added HCl viscous in 300 mL volume, hydrogen peroxide and BaCl 2 /Na 2 SO 4 /Na 2 S then heated to 100°C temperature. Let in room temperature then was filtrated. The solid settled as ThSO 4 /ThS, RaSO 4 /RaS. The filtrate to be settled using 15g (NH 4 ) 2 CO 3 in 100 mL volume of water while mixed until the solution reached pH 2. The solid settled was be dried, then into the filtrate added 10 mL volume of formic acid. The solid settled of filtration was be dried. The solution of filtrate to be settled using (NH 4 ) 2 CO 3 until pH 4. The solid settled was be filtered and dried. The filtrate was be settled using oxalic acid. The analysis of standard of oxide rare earth had been done using XRF Am 241 source. Result of these process got 100 mesh xenotime upgrade those leached in 700°C along 4 hours used (NH 4 )H 2 PO 4 so HRE total lifted up from 4.31 to 8.16%. Resulted of HRE oxide yield was 17.76% in pH 2. HRE oxide yield in pH 4 was 38.45%, and HRE oxide yield was 6.38% as oxalic compound, so the total HRE oxide yield was 62.59%. (author)

  3. Characterization of Rare Earth Element Minerals in Coal Utilization Byproducts

    Energy Technology Data Exchange (ETDEWEB)

    Montross, Scott N. [Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States); Verba, Circe A. [National Energy Technology Lab. (NETL), Albany, OR (United States). Research Innovation Center; Collins, Keith [National Energy Technology Lab. (NETL), Albany, OR (United States). Research Innovation Center

    2017-07-17

    The United States currently produces over 100 million tons of coal utilization byproducts (CUB) per year in the form of fly ash, bottom ash, slag, and flue gas (American Coal Ash Association (ACCA), 2015). But this “waste material” also contains potentially useful levels of rare earth elements (REE). Rare earth elements are crucial for many existing and emerging technologies, but the U.S. lacks a domestic, sustainable REE source. Our project explored the possibility of developing a supply of REEs for U.S. technologies by extracting REEs from CUBs. This work offers the potential to reduce our dependence on other countries for supply of these critical elements (NETL, REE 2016 Project Portfolio). Geologic and diagenetic history, industrial preparation methods, and the specific combustion process all play major roles in the composition of CUB. During combustion, inorganic mineral phases of coal particles are fluidized at temperatures higher than 1400oC, so inorganic mineral materials are oxidized, fused, disintegrated, or agglomerated into larger spherical and amorphous (non-crystalline) particles. The original mineralogy of the coal-containing rock and heating/cooling of the material significantly affects the composition and morphology of the particles in the combustion byproduct (Kutchko and Kim, 2006). Thus, different types of coal/refuse/ash must be characterized to better understand mineral evolution during the combustion process. Our research focused on developing a working model to address how REE minerals behave during the combustion process: this research should help determine the most effective engineering methods for extracting REEs from CUBs. We used multimodal imaging and image processing techniques to characterize six rock and ash samples from different coal power plants with respect to morphology, grain size, presence of mineral phases, and elemental composition. The results of these characterization activities provided thresholds for realizing the

  4. Studi Ekstraksi Bijih Thorit dengan Metode Digesti Asam dan Pemisahan Thorium dari Logam Tanah Jarang dengan Metode Oksidasi-Presipitasi Selektif

    Directory of Open Access Journals (Sweden)

    Moch Iqbal Nur Said

    2017-11-01

    Full Text Available Thorium (Th is a radioactive metal that can be formed along with uranumand rare earth metals (REM. Minerals contain radioactive elements are monazite ((Ce,La,Y,U/ThPO4, thorianite ((Th,UO2, and thorite (ThSiO4. Mamuju Area is containing radioactive minerals, thorite is one of them. To separate REM from radioactive elements can be conducted by exctracting thorium from thorite ore by acid digestion method using sulphuric acid (H2SO4, followed by leaching and thorium recovery in the form of thorium hydroxide by chemical precipitation using ammonium hydroxide (NH4OH. The experimental results showed that the optimum conditions of acid digestion that give the highest Th extraction percentage on solid to liquid ratio are obtained at 1:2 (g/mL in 60 minutes with extraction percentages of Th, iron (Fe and REM are 82.47%, 80.08%, and 83.31% respectively. The highest thorium precipitation percentage, as much as 95.47% , was obtained at pH 4.5 on room temperature (26 ± 1°C. At higher temperature (70°C, a lower percentage of thorium precipitation is obtained, as much as 83.69%. Pre-oxidation by using H2O2 solution with two times stoichiometry for 1.5 hours at room temperature is increasing Fe precipitation percentage from 93.08% to 99.93%.

  5. Column extraction chromatography with HEH (EHP) for separating rare earth elements from coexistent elements and its application

    International Nuclear Information System (INIS)

    Peng Chunlin; Sun Baocheng; Zhao Junwu; Liu Xuan

    1985-01-01

    For separating rare earths from large amount of coexistent elements a new method of column extraction chromatography with HEH (EHP) as a stationary phase and sulphosalicylic acid, gluconic acid, ascorbic acid respectively as a mobile phase has been developed. It has been applied to the determination of trace rare earth elements in nickel-base alloys and iron-nickel-base alloys with satisfactory results

  6. Comparison of the Environment, Health, And Safety Characteristics of Advanced Thorium- Uranium and Uranium-Plutonium Fuel Cycles

    Science.gov (United States)

    Ault, Timothy M.

    The environment, health, and safety properties of thorium-uranium-based (''thorium'') fuel cycles are estimated and compared to those of analogous uranium-plutonium-based (''uranium'') fuel cycle options. A structured assessment methodology for assessing and comparing fuel cycle is refined and applied to several reference fuel cycle options. Resource recovery as a measure of environmental sustainability for thorium is explored in depth in terms of resource availability, chemical processing requirements, and radiological impacts. A review of available experience and recent practices indicates that near-term thorium recovery will occur as a by-product of mining for other commodities, particularly titanium. The characterization of actively-mined global titanium, uranium, rare earth element, and iron deposits reveals that by-product thorium recovery would be sufficient to satisfy even the most intensive nuclear demand for thorium at least six times over. Chemical flowsheet analysis indicates that the consumption of strong acids and bases associated with thorium resource recovery is 3-4 times larger than for uranium recovery, with the comparison of other chemical types being less distinct. Radiologically, thorium recovery imparts about one order of magnitude larger of a collective occupational dose than uranium recovery. Moving to the entire fuel cycle, four fuel cycle options are compared: a limited-recycle (''modified-open'') uranium fuel cycle, a modified-open thorium fuel cycle, a full-recycle (''closed'') uranium fuel cycle, and a closed thorium fuel cycle. A combination of existing data and calculations using SCALE are used to develop material balances for the four fuel cycle options. The fuel cycle options are compared on the bases of resource sustainability, waste management (both low- and high-level waste, including used nuclear fuel), and occupational radiological impacts. At steady-state, occupational doses somewhat favor the closed thorium option while low

  7. Determination of rare and radioactive elements in raw materials

    International Nuclear Information System (INIS)

    Zemtsova, L.I.; Stepanova, N.A.; Zheleznova, E.M.

    1983-01-01

    A methodical guidance on determination of scandium, rare earth elements, zirconium, hafnium, niobium, tantalum, molybdenum, tungsten, rhenium, uranium, radium, thorium in mineral raw materials is presented. Geological mineralogical and analytical characteristics are presented for each of these elements. Modern methods of their determination in different geological objects are described. Optimum spheres of application of each method are pointed out

  8. Quantifying postfire aeolian sediment transport using rare earth element tracers

    Science.gov (United States)

    Dukes, David; Gonzales, Howell B.; Ravi, Sujith; Grandstaff, David E.; Van Pelt, R. Scott; Li, Junran; Wang, Guan; Sankey, Joel B.

    2018-01-01

    Grasslands, which provide fundamental ecosystem services in many arid and semiarid regions of the world, are undergoing rapid increases in fire activity and are highly susceptible to postfire-accelerated soil erosion by wind. A quantitative assessment of physical processes that integrates fire-wind erosion feedbacks is therefore needed relative to vegetation change, soil biogeochemical cycling, air quality, and landscape evolution. We investigated the applicability of a novel tracer technique—the use of multiple rare earth elements (REE)—to quantify soil transport by wind and to identify sources and sinks of wind-blown sediments in both burned and unburned shrub-grass transition zone in the Chihuahuan Desert, NM, USA. Results indicate that the horizontal mass flux of wind-borne sediment increased approximately threefold following the fire. The REE tracer analysis of wind-borne sediments shows that the source of the horizontal mass flux in the unburned site was derived from bare microsites (88.5%), while in the burned site it was primarily sourced from shrub (42.3%) and bare (39.1%) microsites. Vegetated microsites which were predominantly sinks of aeolian sediments in the unburned areas became sediment sources following the fire. The burned areas showed a spatial homogenization of sediment tracers, highlighting a potential negative feedback on landscape heterogeneity induced by shrub encroachment into grasslands. Though fires are known to increase aeolian sediment transport, accompanying changes in the sources and sinks of wind-borne sediments may influence biogeochemical cycling and land degradation dynamics. Furthermore, our experiment demonstrated that REEs can be used as reliable tracers for field-scale aeolian studies.

  9. Rare-earth elements in human colostrum milk.

    Science.gov (United States)

    Poniedziałek, Barbara; Rzymski, Paweł; Pięt, Małgorzata; Niedzielski, Przemysław; Mleczek, Mirosław; Wilczak, Maciej; Rzymski, Piotr

    2017-11-01

    Rare-earth elements (REEs) are used in a growing number of applications, and their release to environment has increased over the decades. Knowledge of REEs in human milk and factors that could possibly influence their concentration is scarce. This study evaluated the concentrations of 16 REEs (Ce, Eu, Er, Gd, La, Nd, Pr, Sc, Sm, Dy, Ho, Lu, Tb, Tm, Y, and Yb) in human colostrum milk collected from Polish women (n = 100) with the ICP-OES technique. The concentrations (mean ± SD) of Pr (41.9 ± 13.2 μg L -1 ), Nd (11.0 ± 4.0 μg L -1 ), La (7.1 ± 5.2 μg L -1 ), and Er (2.2 ± 0.8 μg L -1 ) were found above detection limits. The total mean ± SD concentration of detected REEs was 60.9 ± 17.8 μg L -1 . Current smokers displayed significantly increased Nd concentrations compared to women who had never smoked. No other associations between REEs in colostrum milk and age, diet in pregnancy (food supplement use and frequency of fish, meat, and vegetable consumption) or place of living (urban/rural) were found. This study adds to general understanding of the occurrence and turnover of REEs in women and human fluids.

  10. The Elemental Abundances (with Uncertainties) of the Most Earth-like Planet

    OpenAIRE

    Wang, Haiyang S.; Lineweaver, Charles H.; Ireland, Trevor R.

    2017-01-01

    To first order, the Earth as well as other rocky planets in the Solar System and rocky exoplanets orbiting other stars, are refractory pieces of the stellar nebula out of which they formed. To estimate the chemical composition of rocky exoplanets based on their stellar hosts' elemental abundances, we need a better understanding of the devolatilization that produced the Earth. To quantify the chemical relationships between the Earth, the Sun and other bodies in the Solar System, the elemental ...

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

    Science.gov (United States)

    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.

  12. THORIUM DISPERSION IN BISMUTH

    Science.gov (United States)

    Bryner, J.S.

    1961-07-01

    The growth of thorium bismutaide particles, which are formed when thorium is suspended in liquid bismuth, is inhibited when the liquid metal suspension is being flowed through a reactor and through a heat exchanger in sequence. It involves the addition of as little as 1 part by weight of tellurium to 100 parts of thorium. This addition is sufficient to inhibit particle growth and agglomeration.

  13. Quantifying dust input to the Subarctic North Pacific - Results from surface sediments and sea water thorium isotope measurements

    Science.gov (United States)

    Winckler, G.; Serno, S.; Hayes, C.; Anderson, R. F.; Gersonde, R.; Haug, G. H.

    2012-12-01

    The Subarctic North Pacific is one of the three primary high-nutrient-low chlorophyll regions of the modern ocean, where the biological pump is relatively inefficient at transferring carbon from the atmosphere to the deep sea. The system is thought to be iron-limited. Aeolian dust is a significant source of iron and other nutrients that are essential for the health of marine ecosystems and potentially a controlling factor of the high-nutrient-low chlorophyll status of the Subarctic North Pacific. However, constraining the size of the dust flux to the surface ocean remains difficult. Here we apply two different approaches, based on surface sediment and water column samples, respectively, obtained during the SO202/INOPEX research cruise to the Subarctic North Pacific in 2009. We map the spatial patterns of Th/U isotopes, helium isotopes and rare earth elements across surface sediments from 37 multi-core core-top sediments across the Subarctic North Pacific. In order to deconvolve the detrital endmembers in regions of the North Pacific affected by volcanic material, IRD and hemipelagic input, we use a combination of trace elements with distinct characteristics in the different endmembers. This approach allows us to calculate the relative aeolian fraction, and in combination with Thorium230-normalized mass flux data, to quantify the dust supply. Secondly, we present an innovative approach to use paired Thorium-232 and Thorium-230 concentrations of upper-ocean seawater at 7 stations along the INOPEX track. Thorium-232 in the upper water column is dominantly derived from dissolution of aeolian dust, whereas Thorium-230 data provide a measure of the thorium removal from the surface waters and, thus, allow us to derive Thorium-232 fluxes. Combined with a mean Thorium-232 concentration in dust and estimate of the thorium solubility, the Thorium-232 flux can be translated in a dust flux to the surface ocean. Dust flux estimates for the Subarctic North Pacific will be

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

    Science.gov (United States)

    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)

  15. The influence of a subduction component on magmatism in the Okinawa Trough: Evidence from thorium and related trace element ratios

    Science.gov (United States)

    Guo, Kun; Zeng, Zhi-Gang; Chen, Shuai; Zhang, Yu-Xiang; Qi, Hai-Yan; Ma, Yao

    2017-09-01

    The Okinawa Trough (OT) is a back-arc, initial continental marginal sea basin located behind the Ryukyu Arc-Trench System. Formation and evolution of the OT have been intimately related to subduction of the Philippine Sea Plate (PSP) since the late Miocene; thus, the magma source of the trough has been affected by subduction components, as in the case of other active back-arc basins, including the Lau Basin (LB) and Mariana Trough (MT). We review all the available geochemical data relating to basaltic lavas from the OT and the middle Ryukyu Arc (RA) in this paper in order to determine the influence of the subduction components on the formation of arc and back-arc magmas within this subduction system. The results of this study reveal that the abundances of Th in OT basalts (OTBs) are higher than that in LB (LBBs) and MT basalts (MTBs) due to the mixing of subducted sediments and EMI-like enriched materials. The geochemical characteristics of Th and other trace element ratios indicate that the OTB originated from a more enriched mantle source (compared to N-mid-ocean ridge basalt, N-MORB) and was augmented by subducted sediments. Data show that the magma sources of the south OT (SOT) and middle Ryukyu Arc (MRA) basalts were principally influenced by subducted aqueous fluids and bulk sediments, which were potentially added into magma sources by accretion and underplating. At the same time, the magma sources of the middle OT (MOT) and Kobi-syo and Sekibi-Syo (KBS+SBS) basalts were impacted by subducted aqueous fluids from both altered oceanic crust (AOC) and sediment. The variable geochemical characteristics of these basalts are due to different Wadati-Benioff depths and tectonic environments of formation, while the addition of subducted bulk sediment to SOT and MRA basalts may be due to accretion and underplating, and subsequent to form mélange formation, which would occur partial melting after aqueous fluids are added. The addition of AOC and sediment aqueous fluid

  16. Determination of rare earth elements in pure solutions by X-ray fluorescence method

    International Nuclear Information System (INIS)

    Kuada, T.A.

    1984-01-01

    An X-ray fluorescence method for the determination of rare earth elements in pure solutions is described. The thin film sample preparation technique, by dropping the solution on filter paper as supporting material, has been utilized. The best conditions for X-ray spectrometer operation have been stablished. The analytical lines and internal standard have been selected, defining measurement conditions for each rare earth elements. With the settled parameters, the rare earth elements in pure solutions were determined. The concentration range during the runs was from 0,05 to 5 gRE/L, depending on the element. The standard deviation was less than 10% and the accuracy was between 0,2 to 10% as a function of the concentration. The main interfering lines of others lanthanides were studied for each element, and the method was also applied to fission products represented by the rare earth alements. The method is suitable for individual rare earth element determination in presence of some lanthanides. However, in solutions containing a mixture of all rare earth elements, the X-ray emission spectrum is very complex, making it difficult to get accurated measurements. In relation to fission products represented by rare earth elements, only Ce, Pr, Nd and Sm could be analised in presence of uranium and other fission products. (Author) [pt

  17. Recovery of valuable products from the raffinate of uranium and thorium pilot-plant

    International Nuclear Information System (INIS)

    Martins, E.A.J.

    1990-01-01

    IPEN-CNEN/SP has being very active in refining yellow cake to pure ammonium diuranate which is converted to uranium trioxide, uranium dioxide, uranium tetra-and hexa-fluoride in sequential way. The technology of the thorium purification and its conversion to nuclear grade products has been a practice since several years as well. For both elements the major waste to be worked is the raffinate from purification via TBP-varsol in pulsed columns. In this paper the actual processing technology is reviewed with special emphasis on the recovery of valuable products, mainly nitric acid, ammonium nitrate, uranium, thorium and rare earth elements. Ammonium nitrate from the precipitation of uranium diuranate is of good quality, being radioactivity and uranium-free, and recommended to be applied as fertilizer. In conclusion the main effort is to maximize the recycle and reuse of the above mentioned chemicals. (author)

  18. Rare Earth elements as sediment tracers in Mangrove ecosystems

    Science.gov (United States)

    Ramanathan, A. L.; Swathi, S.

    2013-05-01

    Rare earth elements have been widely used as geochemical source fingerprints of rocks and sediments to study processes involving cosmo-chemistry, igneous petrology, tectonic setting and for investigations of water-rock interactions and weathering processes including transport of weathering products to the oceans.Many studies have addressed the use of REEs in investigating the environmental impact of human activity and demonstrated that the REE natural distribution in sediment from densely industrialised and populated regions can be altered by anthropogenic influences.The coastal wetlands like Mangroves are ultimate sinks for all the material derived from the terrestrial and marine environment.The high productivity and low ratio of sediment respiration to net primary production gives mangrove sediments the potential for long-term sequestration of these pollutants/metals before reaching the coastal ocean. Geochemical study of REE in these sedimentary systems is useful for determining the nature of the biogeochemical processes. In particular, REE show a great sensitivity to pH changes, redox conditions and adsorption/ desorption reactions. So, they may be used as markers of discharge provenance, weathering processes, changes in environmental conditions in the water and sediments of Mangrove/wetland systems. Our study aims to establish the abundance, distribution and enrichment of REEs to track the sediment sources and biogeochemical processes occurring in the mangrove environment.Core sediments were collected from the different environmental settings within the Pichavaram mangrove area.Higher REE concentration in Pichavaram sediments indicated greater input from sources like terrestrial weathering and anthropogenic activities which in turn are affected by saline mixing and dynamic physico-chemical processes occurring in the mangrove environment. REE enrichment order was attributed to the alkaline pH (7-8.5) and reducing conditions prevailing in the mangrove

  19. Thorium: An energy source for the world of tomorrow

    Directory of Open Access Journals (Sweden)

    Revol J.-P.

    2015-01-01

    Full Text Available To meet the tremendous world energy needs, systematic R&D has to be pursued to replace fossil fuels. Nuclear energy, which produces no green house gases and no air pollution, should be a leading candidate. How nuclear energy, based on thorium rather than uranium, could be an acceptable solution is discussed. Thorium can be used both to produce energy and to destroy nuclear waste. The thorium conference, organized by iThEC at CERN in October 2013, has shown that thorium is seriously considered by some major developing countries as a key element of their energy strategy. However, developed countries do not seem to move fast enough in that direction, while global cooperation is highly desirable in this domain. Thorium is not fissile. Various possible ways of using thorium will be reviewed. However, an elegant option is to drive an “Accelerator Driven System (ADS” with a proton accelerator, as suggested by Nobel Prize laureate Carlo Rubbia .

  20. Thorium: An energy source for the world of tomorrow ?

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    To meet the tremendous world energy needs, systematic R&D has to be pursued to replace fossil fuels. The ThEC13 conference organized by iThEC at CERN last October has shown that thorium is seriously considered by developing countries as a key element of their energy strategy. Developed countries are also starting to move in the same direction. How thorium could make nuclear energy (based on thorium) acceptable to society will be discussed. Thorium can be used both to produce energy and to destroy nuclear waste. As thorium is not fissile, one elegant option is to use an accelerator, in so-called “Accelerator Driven Systems (ADS)”, as suggested by Carlo Rubbia. CERN’s important contributions to R&D on thorium related issues will be mentioned as well as the main areas where CERN could contribute to this field in the future.

  1. Neutron activation analysis of the rare earth elements in rocks from the earth's upper mantle and deep crust

    International Nuclear Information System (INIS)

    Stosch, H.-G.; Koetz, J.; Herpers, U.

    1986-01-01

    Three techniques for analyzing rare earth elements (REE) in geological materials are described, i.e. instrumental neutron activation analysis (INAA), neutron activation analysis with pre-irradiation chemical REE separation (PCS-NAA) and radiochemical neutron activation analysis (RNAA). The knowledge of REE concentrationd in eclogites, peridotites and minerals from the earth's lower crust and upper mantle is very useful in constraining their petrogenetic history. (author)

  2. Two main and a new type rare earth elements in Mg alloys: A review

    Science.gov (United States)

    Kong, Linghang

    2017-09-01

    Magnesium (Mg) alloys stand for the lightest structure engineering materials. Moreover, the strengthening of Mg alloys in ductility, toughness and corrosion predominates their wide applications. With adding rare earth elements in Mg, the mechanical properties will be improved remarkably, especially their plasticity and strength. A brief overview of the addition of rare earth elements for Mg alloys is shown. The basic mechanisms of strengthening Mg alloys with rare earth elements are reviewed, including the solid solution strengthening, grain refinement and long period stacking ordered (LPSO) phase. Furthermore, the available rare earth elements are summarized by type, chemical or physical effects and other unique properties. Finally, some challenge problems that the research is facing and future expectations of ra-re-earth Mg alloys are stated and discussed.

  3. Distribution of trace elements in land plants and botanical taxonomy with special reference to rare earth elements and actinium

    International Nuclear Information System (INIS)

    Koyama, Mutsuo

    1989-01-01

    Distribution profiles of trace elements in land plants were studied by neutron activation analysis and radioactivity measurements without activation. Number of botanical samples analyzed were more than three thousand in which more than three hundred botanical species were included. New accumulator plants of Co, Cr, Zn, Cd, rare earth elements, Ac, U, etc., were found. Capabilities of accumulating trace elements can be related to the botanical taxonomy. Discussions are given from view points of inorganic chemistry as well as from botanical physiology

  4. Science and technology of the rare earth elements

    International Nuclear Information System (INIS)

    Azzouz, Abdelkrim; Chegrouche, Salah; Telmoune, Sid-Ali; Layachi, Lazhar

    1992-07-01

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

  5. Technology of thorium concentrates purification and their transformation in pure nuclear products

    International Nuclear Information System (INIS)

    Ikuta, A.

    1977-01-01

    An experimental study for the purification of thorium concentrates by solvent extraction is presented. The product of purification is appropriate for utilization in the fabrication of nuclear reactor fuel elements. The experiments are carried out in a laboratory scale and the following operations are studied: dissolution, extraction-scrubbing, stripping-scrubbing, thorium oxalate precipitation, and thorium nitrate coagulation [pt

  6. Reversed-phase thin-layer chromatography of the rare earth elements

    International Nuclear Information System (INIS)

    Kuroda, R.; Adachi, M.; Oguma, K.

    1988-01-01

    Partition chromatographic behaviour of the rare earth elements on C 18 bonded silica reversed-phase material has been investigated by thin-layer chromatography in methanol - lactate media. The rare earth lactato complexes are distributed and fractionated on bonded silica layers without ion-interaction reagents. The concentration and pH of lactate solution, methanol concentration and temperature have effects on the migration and resolution of the rare earth elements. The partition system is particularly suited to separate adjacent rare earths of middle atomic weight groups, allowing the separation of gadolinium, terbium, dysprosium, holmium, erbium and thulium to be achieved by development to 18 cm distance. (orig.)

  7. Review of rare earth element concentrations in oil shales of the Eocene Green River Formation

    Science.gov (United States)

    Birdwell, Justin E.

    2012-01-01

    Concentrations of the lanthanide series or rare earth elements and yttrium were determined for lacustrine oil shale samples from the Eocene Green River Formation in the Piceance Basin of Colorado and the Uinta Basin of Utah. Unprocessed oil shale, post-pyrolysis (spent) shale, and leached shale samples were examined to determine if oil-shale processing to generate oil or the remediation of retorted shale affects rare earth element concentrations. Results for unprocessed Green River oil shale samples were compared to data published in the literature on reference materials, such as chondritic meteorites, the North American shale composite, marine oil shale samples from two sites in northern Tibet, and mined rare earth element ores from the United States and China. The Green River oil shales had lower rare earth element concentrations (66.3 to 141.3 micrograms per gram, μg g-1) than are typical of material in the upper crust (approximately 170 μg g-1) and were also lower in rare earth elements relative to the North American shale composite (approximately 165 μg g-1). Adjusting for dilution of rare earth elements by organic matter does not account for the total difference between the oil shales and other crustal rocks. Europium anomalies for Green River oil shales from the Piceance Basin were slightly lower than those reported for the North American shale composite and upper crust. When compared to ores currently mined for rare earth elements, the concentrations in Green River oil shales are several orders of magnitude lower. Retorting Green River oil shales led to a slight enrichment of rare earth elements due to removal of organic matter. When concentrations in spent and leached samples were normalized to an original rock basis, concentrations were comparable to those of the raw shale, indicating that rare earth elements are conserved in processed oil shales.

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

    Science.gov (United States)

    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...

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

    International Nuclear Information System (INIS)

    Stoch, H.; Steele, T.W.; Copelowitz, I.

    1976-01-01

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

  10. Rare earth elements in weathering profiles and sediments of Minnesota: Implications for provenance studies

    Science.gov (United States)

    Morey, G.B.; Setterholm, D.R.

    1997-01-01

    The relative abundance of rare earth elements in sediments has been suggested as a tool for determining their source rocks. This correlation requires that weathering, erosion, and sedimentation do not alter the REE abundances, or do so in a predictable manner. We find that the rare earth elements are mobilized and fractionated by weathering, and that sediments derived from the weathered materials can display modifications of the original pattern of rare earth elements of some due to grain-size sorting of the weathered material. However, the REE distribution pattern of the provenance terrane can be recognized in the sediments.

  11. The elemental abundances (with uncertainties) of the most Earth-like planet

    Science.gov (United States)

    Wang, Haiyang S.; Lineweaver, Charles H.; Ireland, Trevor R.

    2018-01-01

    To first order, the Earth as well as other rocky planets in the Solar System and rocky exoplanets orbiting other stars, are refractory pieces of the stellar nebula out of which they formed. To estimate the chemical composition of rocky exoplanets based on their stellar hosts' elemental abundances, we need a better understanding of the devolatilization that produced the Earth. To quantify the chemical relationships between the Earth, the Sun and other bodies in the Solar System, the elemental abundances of the bulk Earth are required. The key to comparing Earth's composition with those of other objects is to have a determination of the bulk composition with an appropriate estimate of uncertainties. Here we present concordance estimates (with uncertainties) of the elemental abundances of the bulk Earth, which can be used in such studies. First we compile, combine and renormalize a large set of heterogeneous literature values of the primitive mantle (PM) and of the core. We then integrate standard radial density profiles of the Earth and renormalize them to the current best estimate for the mass of the Earth. Using estimates of the uncertainties in i) the density profiles, ii) the core-mantle boundary and iii) the inner core boundary, we employ standard error propagation to obtain a core mass fraction of 32.5 ± 0.3 wt%. Our bulk Earth abundances are the weighted sum of our concordance core abundances and concordance PM abundances. Unlike previous efforts, the uncertainty on the core mass fraction is propagated to the uncertainties on the bulk Earth elemental abundances. Our concordance estimates for the abundances of Mg, Sn, Br, B, Cd and Be are significantly lower than previous estimates of the bulk Earth. Our concordance estimates for the abundances of Na, K, Cl, Zn, Sr, F, Ga, Rb, Nb, Gd, Ta, He, Ar, and Kr are significantly higher. The uncertainties on our elemental abundances usefully calibrate the unresolved discrepancies between standard Earth models under

  12. Qualitative analysis of the rare earth element by simulation of inductively coupled plasma emission spectra

    International Nuclear Information System (INIS)

    Hashimoto, M.S.; Tobishima, Taeko; Kamitake, Seigo; Yasuda, Kazuo.

    1985-01-01

    The emission lines for qualitative analysis of rare earth elements by a simulation technique of ICP spectra were proposed. The spectra were simulated by employing a Gaussian (or a Lorentzian at high concentrations) profile. The simulated spectra corresponded quite well with the observed ones. The emission lines were selected so that the interference was as small as possible. The present qualitative analysis is based on a pattern recognition method where observed intensity ratios of the emission lines in each element are compared with those of a single analyte element. The qualitative analysis was performed for twelve standard solutions containing a single rare earth element and for eight standard solutions containing an element other than rare earth elements. The selection of the emission lines and the algorithm of the present qualitative analysis were justified. (author)

  13. On the new type of thorium-rare metal mineralization related to carbonatite complexes

    International Nuclear Information System (INIS)

    Bargasarov, Yu.A.; Ginzburg, A.I.; Frolov, A.A.

    1974-01-01

    A description is given of a new type of thorium-rare metal mineralization which is genetically associated with alkaline-ultrabasic carbonate complexes and controlled by the same fractured zones as these plutons. Deposits of this type occur over non-outcropping masses of ultrabasic alkaline rocks and carbonatites or on their continuations and are regarded as typical supraintrusive formations, highly characteristic regions in which elements from these rock masses are deposited. Here are concentrated those elements which are removed from the ultrabasic alkaline rocks when carbonatites devlop in them, viz. sodium, silicon, rare earths, thorium, barium, scandium, etc. Such deposits are formed in several stages; the early stages are characterized by intensive processes of silicification (outer aureoles of fenitization) and albitization, with which thorite-xenotime mineralization is associated. The later stages are very similar in composition to the ankerite carbonatites. The localization of all stages of the hydrothermal process along the same tectonic zones is responsible for the development of telescopic phenomena and the highly characteristic nature of such deposits. The occurrence of mineralized zones with rare-earth and thorium mineralization in a number of cases may indicate the presence of deep hidden carbonatite rock masses which have no outcrop, a fact which should be taken into account during prospective work. (author)

  14. Dissolved rare earth elements in the Black Sea

    NARCIS (Netherlands)

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

    1991-01-01

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

  15. Mineralogy and trace element chemistry of the Siliceous Earth of ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    We report the presence of a 3–5 cm thick loose fragmental layer in the Siliceous Earth at Matti ka. Gol in the Barmer basin of Rajasthan. Petrographic, chemical and mineralogical study reveals the presence of abundant volcanic debris such as glass shards, agglutinates, hollow spheroids, kinked biotites, feldspars showing ...

  16. Accumulation of rare earth elements by siderophore- forming ...

    Indian Academy of Sciences (India)

    2012-01-08

    Jan 8, 2012 ... In this study, Arthrobacter luteolus, isolated from rare earth environment of Chavara (Quilon district, Kerala, India), were found to produce .... thene cover and brought to the laboratory in an icebox to avoid microbial contamination and proliferation during transport. 2.2 ICP-MS analysis of soil. An adopted ...

  17. Qualitative analysis of rare earth elements contained in the phosphogypsum

    International Nuclear Information System (INIS)

    Chegrouche, S.; Mellah, A.

    1992-10-01

    In this study, we have characterized the phosphogypsum from the industrial phosphoric acid of Annaba chemical plant (Algeria). This procedure was achieved by x-ray diffraction in order to know different forms of sulphates contained in the phosphogypsum before its treatment. After chemical treatment, we have identified qualitatively the rare earth by x-ray fluorescence spectrometry

  18. Mineralogy and trace element chemistry of the Siliceous Earth of ...

    Indian Academy of Sciences (India)

    We report the presence of a 3-5 cm thick loose fragmental layer in the Siliceous Earth at Matti ka Gol in the Barmer basin of Rajasthan. Petrographic, chemical and mineralogical study reveals the presence of abundant volcanic debris such as glass shards, agglutinates, hollow spheroids, kinked biotites, feldspars showing ...

  19. SEPARATION OF URANIUM FROM THORIUM AND PROTACTINIUM

    Science.gov (United States)

    Musgrave, W.K.R.

    1959-06-30

    This patent relates to the separation of uranium from thorium and protactinium; such mixtures of elements usually being obtained by neutron irradiation of thorium. The method of separating the constituents has been first to dissolve the mixture of elements in concertrated nitric acid and then to remove the protactinium by absorption on manganese dioxide and the uranium by solvent extraction with ether. Prior to now, comparatively large amounts of thorium were extracted with the uranium. According to the invention this is completely prevented by adding sodium diethyldithiocarbamate to the mixture of soluble nitrate salts. The organic salt has the effect of reacting only with the uranyl nitrate to form the corresponding uranyl salt which can then be selectively extracted from the mixture with amyl acetate.

  20. Diagenetic remobilization of rare earth elements in a sediment core from the central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N.; Banakar, V.K.

    Rare earth elements (REE) distribution in a 36 cm long sediment box core from the Central Indian Basin is studied. REE concentration is generally higher in the upper oxic zone than in intermediate suboxic zone suggesting REE diffusion upwards...

  1. Rare earth element patterns of the Central Indian Basin sediments related to their lithology

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.; Roelandts, I.; Sudhakar, M.; Pluger, W.L.

    Rare earth element (REE) concentration have been determined in terrigenous, siliceous (nodule barren and nodule bearing), calcareous, and red clay from the Central Indian Basin. The bulk distribution of REE, and in particular the relative cerium...

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

    Science.gov (United States)

    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.

  3. [Analysis of rare earth elements in pu'er tea of Yunnan by ICP-AES].

    Science.gov (United States)

    Ning, Peng-bo; Gong, Chun-mei; Zhang, Yan-ming; Guo, Kang-kang

    2010-10-01

    The 150 samples of pu'er tea collected from the main producing area of Yunnan were detected by ICP-AES method, to investigate the current safety status of pu'er tea rare earth elements. The rare earth elements contents were found to be in the range 0.26-4.07 mg x kg(-1) in all detected samples, with the 43.0% samples exceeding the maximum levels of contaminants of 2 mg x kg(-1) set by GB 2762-2005 "Maximum levels of contaminants in foods". There was a significant difference between ripened tea rare earth elements and raw tea's from the same sources, which affected some ripened tea quality at last. There was a significant difference among the rare earth elements contents of the pu'er tea main producing areas, and the condition of pu'er tea quality and safety controlling was not optimistic at individual producing areas.

  4. Preconcentration of trace elements from high-purity thorium and uranium on Chelex-100 and determination by graphite furnace atomic absorption spectrometry with Zeeman-effect background correction

    International Nuclear Information System (INIS)

    Raje, Naina; Kayasth, Satish; Asari, T.P.S.; Gangadharan, S.

    1994-01-01

    Preconcentration of trace impurities from large-sized samples of uranium metal and thorium oxide using a small column of Chelex-100 followed by their determination using graphite furnace atomic absorption spectrometry (GFAAS) is reported. A 0.5-10-g amount of the sample (uranium metal or thorium oxide) was dissolved, complexed with ammonium carbonate and subjected to the ion-exchange procedure. The retained analytes were eluted with 2-4 M nitric acid and brought to a small volume for a final dilution to 10-25 ml for their determination using GFAAS. The validity of the separation procedure and recoveries at μg kg -1 levels was checked by standard addition; the recoveries were >95%

  5. Rare earth element mineralogy and geochemistry in a laterite profile from Madagascar

    DEFF Research Database (Denmark)

    Berger, Alfons; Janots, Emilie; Gnos, Edwin

    2014-01-01

    In this study, rare earth element (REE) distribution has been investigated in a weathering profile from central Madagascar. Combination of bulk rock geochemical data (elements and isotopes) with mineral characterization reveals a remarkable evolution of the REE abundances and REE-minerals in the ......In this study, rare earth element (REE) distribution has been investigated in a weathering profile from central Madagascar. Combination of bulk rock geochemical data (elements and isotopes) with mineral characterization reveals a remarkable evolution of the REE abundances and REE...

  6. Quantitative analysis of thorium-containing materials using an Industrial XRF analyzer

    International Nuclear Information System (INIS)

    Hasikova, J.; Titov, V.; Sokolov, A.

    2014-01-01

    Thorium (Th) as nuclear fuel is clean and safe and offers significant advantages over uranium. The technology for several types of thorium reactors is proven but still must be developed on a commercial scale. In the case of commercialization of thorium nuclear reactor thorium raw materials will be on demand. With this, mining and processing companies producing Th and rare earth elements will require prompt and reliable methods and instrumentation for Th quantitative on-line analysis. Potential applicability of X-ray fluorescence conveyor analyzer CON-X series is discussed for Th quantitative or semi-quantitative on-line measurement in several types of Th-bearing materials. Laboratory study of several minerals (zircon sands and limestone as unconventional Th resources; monazite concentrate as Th associated resources and uranium ore residues after extraction as a waste product) was performed and analyzer was tested for on-line quantitative measurements of Th contents along with other major and minor components. Th concentration range in zircon sand is 50-350 ppm; its detection limit at this level is estimated at 25- 50 ppm in 5 minute measurements depending on the type of material. On-site test of the CON-X analyzer for continuous analysis of thorium traces along with other elements in zircon sand showed that accuracy of Th measurements is within 20% relative. When Th content is higher than 1% as in the concentrate of monazite ore (5-8% ThO 2 ) accuracy of Th determination is within 1% relative. Although preliminary on-site test is recommended in order to address system feasibility at a large scale, provided results show that industrial conveyor XRF analyzer CON-X series can be effectively used for analytical control of mining and processing streams of Th-bearing materials. (author)

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

    Directory of Open Access Journals (Sweden)

    Yliruokanen, I.

    1995-12-01

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

  8. Rare earth elements and oxides in liquid phase epitaxy

    Czech Academy of Sciences Publication Activity Database

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

    2006-01-01

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

  9. Comparative study using different resins to determine thorium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, Mychelle M.L.; Silva, Paulo S.C.; Maihara, Vera A., E-mail: my_linhares@yahoo.com.br, E-mail: pscsilva@ipen.br, E-mail: vmaihara@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Taddei, Maria Helena T., E-mail: mhtaddei@cnen.gov.br [Comissão Nacional de Energia Nuclear (LAPOC/CNEN), Poços de Caldas, MG (Brazil). Laboratório de Pocos de Caldas; Cheberle, Luan T.V., E-mail: luancheberle@gmail.com [Ambientis Radioproteção, Barueri, SP (Brazil)

    2017-07-01

    Thorium is a naturally occurring radioactive element that is widely distributed in the crust of the Earth. This element is very common in mineral formations in regions with high levels of natural radioactivity, therefore, its determination in environmental samples is important. Thorium isotopes ({sup 228}Th, {sup 230}Th, and {sup 232}Th) were determined in a reference material, the IAEA Soil 327 sample, to validate the two methods employed using different resins. The initial preparation with acid dissolution is the same to both, in the first is used anion exchange resin (DOWEX 1 x 2) and electrodeposition in silver planchets. And in the second method is used a specific chromatographic resin (TEVA) and cerium fluoride microprecipitation. At the end both analysis are quantified by alpha spectrometry. The two methods the results obtained were satisfactory for the reference material used, with relative error of less than 4% for {sup 228}Th, {sup 230}Th, and {sup 232}Th. The main differences found between them were spectrums resolutions, time and cost of analysis. (author)

  10. A miniature single element effusion cell for the vacuum deposition of transition-metal and rare-earth elements

    Science.gov (United States)

    Harris, V. G.; Koon, N. C.

    1997-08-01

    A miniature single element effusion cell has been fabricated and tested that allows for the high-vacuum deposition of a variety of transition-metal and rare-earth elements. The cell is designed to operate under high-vacuum conditions, ≈10-9 Torr, with low power demands, <200 W. The virtues of this evaporator are the simplicity of design and ease of fabrication, assembly, maintenance, and operation.

  11. A Geochemical Analysis of Rare Earth Elements Associated with Significant Phosphate Deposits of West-Central Florida

    Science.gov (United States)

    Turner, K. M.; Owens, J. D.

    2017-12-01

    Rare earth elements (REEs) such as the lanthanide series as well as yttrium, uranium, and thorium are an important industrial resource for expanding technological sectors; therefore, demand and production will continue to increase. Increased market prices resulting in decreased demand has led to new exploration for REE mineral resources in North America. Phosphorite deposits are being investigated as a possible supply but the overall concentrations, depositional environments, and ages are relatively unexplored. Phosphorite is commonly associated with ocean floor sediment deposition and upwelling; however, it may also form in estuarine and supratidal zones with low wave activity, present along Florida's west coast. Interestingly, it seems that major ancient phosphorite deposits are often, if not always, associated with major icehouse conditions (widespread glaciations) and rarely observed during greenhouse conditions. By analyzing a set of sonic drill cores, spatiotemporal REE concentrations can be better constrained for a wide-age range of the Miocene-Pliocene aged Bone Valley Member of the Peace River Formation, the largest North American phosphate deposit. We present concentrations from a depth-transect of samples collected in West-Central Florida, showing the phosphatic sands and silts of the area are highly enriched sedimentary archives for REE, yielding concentrations up to 200 ppm for some REE. The weathering and transport of igneous and metamorphic minerals from the southern Appalachians to the Florida coast where a series of winnowing events occurred may explain the enrichment seen by our data. Sediment cores showing well-rounded quartz sands, dolomitic silts, teeth, bones, and marine fossils commonly found in a near shore depositional environment support this hypothesis. Previous analysis of phosphate grains, teeth, bones, and bulk sediment indicate REE are not associated with and/or sourcing from biogenic components, but rather entering the lattice

  12. Thorium Energy Futures

    Energy Technology Data Exchange (ETDEWEB)

    Peggs, Stephen; Roser, Thomas; Parks, G; Lindroos, Mats; Seviour, Rebecca; Henderson, Stuart; Barlow, R; Cywinski, R; Biarrote, J -L; Norlin, A; Ashley, V; Ashworth, R; Hutton, Andrew; Owen, H; McIntyre, Peter

    2012-07-01

    The potential for thorium as an alternative or supplement to uranium in fission power generation has long been recognised, and several reactors, of various types, have already operated using thorium-based fuels. Accelerator Driven Subcritical (ADS) systems have benefits and drawbacks when compared to conventional critical thorium reactors, for both solid and molten salt fuels. None of the four options - liquid or solid, with or without an accelerator - can yet be rated as better or worse than the other three, given today's knowledge. We outline the research that will be necessary to lead to an informed choice.

  13. Application of stochastic approach based on Monte Carlo (MC) simulation for life cycle inventory (LCI) of the rare earth elements (REEs) in beneficiation rare earth waste from the gold processing: case study

    Science.gov (United States)

    Bieda, Bogusław; Grzesik, Katarzyna

    2017-11-01

    The study proposes an stochastic approach based on Monte Carlo (MC) simulation for life cycle assessment (LCA) method limited to life cycle inventory (LCI) study for rare earth elements (REEs) recovery from the secondary materials processes production applied to the New Krankberg Mine in Sweden. The MC method is recognizes as an important tool in science and can be considered the most effective quantification approach for uncertainties. The use of stochastic approach helps to characterize the uncertainties better than deterministic method. Uncertainty of data can be expressed through a definition of probability distribution of that data (e.g. through standard deviation or variance). The data used in this study are obtained from: (i) site-specific measured or calculated data, (ii) values based on literature, (iii) the ecoinvent process "rare earth concentrate, 70% REO, from bastnäsite, at beneficiation". Environmental emissions (e.g, particulates, uranium-238, thorium-232), energy and REE (La, Ce, Nd, Pr, Sm, Dy, Eu, Tb, Y, Sc, Yb, Lu, Tm, Y, Gd) have been inventoried. The study is based on a reference case for the year 2016. The combination of MC analysis with sensitivity analysis is the best solution for quantified the uncertainty in the LCI/LCA. The reliability of LCA results may be uncertain, to a certain degree, but this uncertainty can be noticed with the help of MC method.

  14. Rare earth elements in semiconductors. Characterization-Part II

    Czech Academy of Sciences Publication Activity Database

    Zavadil, Jiří; Procházková, Olga; Žďánský, Karel

    1999-01-01

    Roč. 7, č. 2 (1999), s. 48-51 [Chinese-Czech Symposium Advanced Materials and Devices for Optoelectronics /2./. Beijing, 13.09.1999-14.09.1999] R&D Projects: GA ČR GA102/99/0341 Grant - others:AV ČR(CZ) KSK1010601 Projekt 7/96/K:4074 Institutional research plan: CEZ:AV0Z2067918 Keywords : rare earth compounds * III-V semiconductors * photoluminescence Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  15. Determination of thorium and uranium isotopes in the mining lixiviation liquor samples

    Energy Technology Data Exchange (ETDEWEB)

    Reis Júnior, Aluísio de Souza; Monteiro, Roberto Pellacani Guedes, E-mail: reisas@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    The alpha spectrometric analysis refers to determination of thorium and uranium isotopes in the mining lixiviation liquor samples. The analytical procedure involves sample preparation steps for rare earth elements, thorium and uranium separation using selective etching with hydrofluoric acid and further radiochemical separation of these using TRU chromatographic resins (Eichrom Industries Inc. USA) besides electroplating of the isolated radionuclides. An isotopic tracer is used to determine the overall chemical yield and to ensure traceability to a national standard. The results are compared to results obtained for the same samples by Becquerel laboratory. We improved the method looking for reproducibility and isotopes isolation as required by alpha spectrometry and the method showing effective in analysis of mining liquor. (author)

  16. Distribution patterns of rare earth elements in various plant species

    Energy Technology Data Exchange (ETDEWEB)

    Wyttenbach, A.; Tobler, L.; Furrer, V. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    The elements La, Ce, Nd, Sm, Eu, Gd, Tb, Yb and Lu have been determined in 6 different plant species by neutron activation analysis. When the concentrations of each species were normalized to Norway spruce, smooth curves were obtained which revealed systematic inter-species differences. (author) 3 figs., 4 refs.

  17. Anomalous scattering factors of some rare earth elements evaluated ...

    Indian Academy of Sciences (India)

    The real and imaginary parts, '() and ''() of the dispersion corrections to the forward Rayleigh scattering amplitude (also called anomalous scattering factors) for the elements La, Ce, Pr, Nd, Sm, Gd, Dy, Ho and Er, have been determined by a numerical evaluation of the dispersion integral that relates them through the ...

  18. Anomalous scattering factors of some rare earth elements evaluated

    Indian Academy of Sciences (India)

    The real and imaginary parts, '() and ''() of the dispersion corrections to the forward Rayleigh scattering amplitude (also called anomalous scattering factors) for the elements La, Ce, Pr, Nd, Sm, Gd, Dy, Ho and Er, have been determined by a numerical evaluation of the dispersion integral that relates them through the ...

  19. Modification of Ni-Mn-Ga ferromagnetic shape memory alloy by addition of rare earth elements

    International Nuclear Information System (INIS)

    Tsuchiya, Koichi; Tsutsumi, Akinori; Ohtsuka, Hideyuki; Umemoto, Minoru

    2003-01-01

    Effect of addition of rare earth elements, such as, Nd, Sm and Tb, was investigated on various properties of Ni-Mn-Ga ferromagnetic shape memory alloys (SMAs). The solubility of the rare earth in the L2 1 phase was found to be very low, most likely less than 0.1 mol%. Insolvable rare earth segregated into subgrain boundaries or grain boundaries to form precipitates. Phase transformation behavior and the structure of martensite phase exhibit a similar dependence on valence electron concentration to those in ternary Ni-Mn-Ga alloys. It was revealed that the addition of rare earth significantly improves the compressive ductility of the alloy

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    earth material, and there are indications that Chinese rare earth exports will decrease in the near future as China seeks to maintain a sufficient supply of these materials. The magnetic properties of some particular rare-earth elements have made them very useful in producing high power density...... electrical machines. Such machines are utilized in applications such as electric cars, and wind turbines. This paper will examine the rare earth supply issue, in order to comment on its relevance to the wind turbine industry. The wind turbine topologies which are currently being used are compared...

  1. The determination of the rare earth elements in naturally-occurring materials zy flame spectroscopy

    International Nuclear Information System (INIS)

    Watts, J.C.

    1975-01-01

    Because the quantitative collection of the rare-earth elements retains natural abundance ratios, adequate analytical methodology incorporates their individual sensitivities, and tolerates their mutual contamination. To achieve these ends, the sensitivities of 15 rare-earths in flame emission were determined in the unseparated nitrous oxide/acetylene flame, their mutual interference ascertained at practical concentrations, and useful emission lines selected for their determination in natural materials. Sources of atomic emission interference were extraneous in origin. Fe in the determination of Dy and Zr in the determination of Nd. Inter-element interferences of the rare-earth elements were minimal after wavelength selection and reduction of the spectral band width. For comparison, five rare earths were determined by flame AAS. (author)

  2. Distribution of the rare earth elements in the sediments of the ...

    African Journals Online (AJOL)

    Rare earth elements (REE), define a group of fifteen chemical elements from lanthanum to lutetium (atomic numbers 57-71) characterized by similar chemical properties. To study their distribution in sediment samples of the Bouregreg river and its tributaries, 10 sampling sites have been chosen. The collected sediment ...

  3. Extractive Separation of Scandium from Rare Earth Elements

    Directory of Open Access Journals (Sweden)

    Zlobina Elena

    2017-01-01

    Full Text Available The extractive separation of scandium and rare earth metals (REM was studied. The extractants used are trialkylbenzylammonium di-2-ethylhexylphosphate (TABAC-D2EHPA, binary extractant and trioctylphosphine oxide (TOPO. The effect of concentration and nature of mineral acids on the scandium recovery was studied. Changing the HNO3 concentration in the range of 0.01 – 2.0 mol/L does not affect the extraction of metals by binary extractant, extraction corresponds to the following row: La, Eu, Gd < Tb earth metals by single extraction. Extraction of scandium by trioctylphosphineoxide from HCl solution proceeds quantitatively in the range of 0.5 – 7.0 mol/L, an increased HNO3 concentration leads to the decrease in scandium extraction. The conditions for the extractive separation of scandium and REM using TOPO solution were determined: scandium can be isolated selectively at the HNO3 concentration of 0.5 mol/L REM are transferred into the organic phase at the HNO3 concentration of 5.0 mol/L. It was determined that the organic phase extracts the compounds of the following composition: (ScA3 + R3R′NCl (HA - D2EHPA, R3R'NCl - TABAC and [Sc(NO33·3TOPO].

  4. Minerals yearbook, 1988: Thorium

    International Nuclear Information System (INIS)

    Hedrick, J.B.

    1988-01-01

    Mine production of monazite, the principal source of thorium, decreased slightly in 1988. Associated Minerals (USA) Inc. was the only domestic monazite producer. Monazite produced in the United States was exported, and the thorium products used domestically were derived from imported materials, existing company stocks, and thorium nitrate released from the National Defense Stockpile. Major nonenergy uses were in refractory applications, ceramics, and mantles for incandescent lanterns. The only energy use of thorium in the United States was in the high-temperature gas-cooled (HTGC) nuclear reactor at Fort St. Vrain, CO. Topics discussed in the report include domestic data coverage, legislation and government programs, domestic production, consumption and uses, stocks, prices, foreign trade, world capacity, and world review--(Australia, Brazil, Madagascar, Mozambique)

  5. Thorium ore deposits

    International Nuclear Information System (INIS)

    Angelelli, Victorio.

    1984-01-01

    The main occurences of the thorium minerals of the Argentine Republic which have not been exploited, due to their reduced volume, are described. The thoriferous deposits have three genetic types: pegmatitic, hydrothermal and detritic, being the most common minerals: monazite, thorite and thorogummite. The most important thorium accumulations are located in Salta, being of less importance those of Cordoba, Jujuy and San Juan. (M.E.L.) [es

  6. A New Discrimination Scheme for Oceanic Ferromanganese Deposits using High Field Strength and Rare Earth Elements

    OpenAIRE

    Josso, P.; Pelleter, Ewan; Pourret, O.; Fouquet, Yves; Etoubleau, Joel; Cheron, Sandrine; Bollinger, C.

    2017-01-01

    Ferromanganese (Fe-Mn) deposits constitute a ubiquitous mineral type in oceanic settings, with metal (Cu, Ni, Zn, Co, Pt) and rare earth elements (REE) enrichments of potential economic interest. Routine analysis of trace elements by ICP-MS has advanced our understanding of the impact of hydrogenetic, diagenetic and hydrothermal processes on the mobility and interaction of high field strength elements (HFSE: Zr, Ti) and REE and yttrium (REY) with Fe-Mn oxyhydroxides. Recent discoveries in the...

  7. Determination of microquantities of zirconium and thorium in uranium dioxide

    International Nuclear Information System (INIS)

    Weber de D'Alessio, Ana; Zucal, Raquel.

    1975-07-01

    A method for the determination of 10 to 50 ppm of zirconium and thorium in uranium IV oxide of nuclear purity is established. Zirconium and thorium are retained in a strong cation-exchange resin Dowex 50 WX8 in 1 M HCl. Zirconium is eluted with 0,5% oxalic acid solution and thorium with 4% ammonium oxalate. The colorimetric determination of zirconium with xilenol orange is done in perchloric acid after destructtion of oxalic acid and thorium is determined with arsenazo III in 5 M HCl. 10 μg of each element were determined with a standard deviation of 2,1% for thorium and 3,4% for zirconium. (author) [es

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

    Science.gov (United States)

    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.

  9. Levels of major and trace elements, including rare earth elements, and ²³⁸U in Croatian tap waters.

    Science.gov (United States)

    Fiket, Željka; Rožmarić, Martina; Krmpotić, Matea; Benedik, Ljudmila

    2015-05-01

    Concentrations of 46 elements, including major, trace, and rare earth elements, and (238)U in Croatian tap waters were investigated. Selected sampling locations include tap waters from various hydrogeological regions, i.e., different types of aquifers, providing insight into the range of concentrations of studied elements and (238)U activity concentrations in Croatian tap waters. Obtained concentrations were compared with the Croatian maximum contaminant levels for trace elements in water intended for human consumption, as well as WHO and EPA drinking water standards. Concentrations in all analyzed tap waters were found in accordance with Croatian regulations, except tap water from Šibenik in which manganese in concentration above maximum permissible concentration (MPC) was measured. Furthermore, in tap water from Osijek, levels of arsenic exceeded the WHO guidelines and EPA regulations. In general, investigated tap waters were found to vary considerably in concentrations of studied elements, including (238)U activity concentrations. Causes of variability were further explored using statistical methods. Composition of studied tap waters was found to be predominately influenced by hydrogeological characteristics of the aquifer, at regional and local level, the existing redox conditions, and the household plumbing system. Rare earth element data, including abundances and fractionation patterns, complemented the characterization and facilitated the interpretation of factors affecting the composition of the analyzed tap waters.

  10. Prospective thorium fuels for future nuclear energy generation

    Energy Technology Data Exchange (ETDEWEB)

    Lainetti, Paulo E.O., E-mail: lainetti@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-07-01

    In the beginning of the Nuclear Era, many countries were interested on thorium, particularly during the 1950 1970 periods. Nevertheless, since its discovery almost two centuries ago, the use of thorium has been restricted to gas mantles employed in gas lighting. The future world energy needs will increase and, even if we assumed a conservative contribution of nuclear generation, it will be occur a significant increasing in the uranium prices, taking into account that uranium, as used in the present thermal reactors, is a finite resource. Nowadays approximately the worldwide yearly requirement of uranium for about 435 nuclear reactors in operation is 65,000 metric t. Therefore, alternative solutions for future must be developed. Thorium is nearly three times more abundant than uranium in The Earth's crust. Despite thorium is not a fissile material, {sup 232}Th can be converted to {sup 233}U (fissile) more efficiently than {sup 238}U to {sup 239}Pu. Besides this, thorium is an environment alternative energy source and also inherently resistant to proliferation.. Many countries had initiated research on thorium in the past, Nevertheless, the interest evanesced due new uranium resources discoveries and availability of enriched uranium at low prices from obsolete weapons. Some papers evaluate the thorium resources in Brazil over 1.200.000 metric t. Then, the thorium alternative must be seriously considered in Brazil for strategic reasons. A brief history of thorium and its utilization are presented, besides a very short discussion about prospective thorium nuclear fuels for the next generation of nuclear reactors. (author)

  11. Changes in the Concentration of Some Rare Earth Elements in Coal Waste

    Science.gov (United States)

    Nowak, Jacek; Kokowska-Pawłowska, Magdalena

    2017-09-01

    Coal waste is formed during coal mining and processing operations. That waste comprises mainly sedimentary rocks that occur in roofs and floors of underground workings and in partings in coal seams. It contains numerous trace elements, including rare earth elements (REEs). Hypergenic processes that take place in coal waste piles may lead to endogenous fires. Thermal transformations of waste have an effect on changes in its phase and chemical composition, including the concentration of trace elements. The paper presents changes in the content of selected rare earth elements (Sc, Y, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu) in wastes of varying degree of thermal transformation. The results of REE content determination in lump samples were subjected to statistical analysis and coefficients of correlation between the studied rare earth elements and the main chemical constituents were determined. The primary carriers of REEs in coal waste are clay minerals. Phase transformations that take place at high temperatures (including dehydroxylation of clay minerals and formation of minerals characteristic of contact metamorphism) cause changes in the concentration of rare earth elements.

  12. Electro-kinetic Separation of Rare Earth Elements Using a Redox-Active Ligand.

    Science.gov (United States)

    Fang, Huayi; Cole, Bren E; Qiao, Yusen; Bogart, Justin A; Cheisson, Thibault; Manor, Brian C; Carroll, Patrick J; Schelter, Eric J

    2017-10-16

    Purification of rare earth elements is challenging due to their chemical similarities. All of the deployed separation methods rely on thermodynamic properties, such as distribution equilibria in solvent extraction. Rare-earth-metal separations based on kinetic differences have not been examined. Herein, we demonstrate a new approach for rare-earth-element separations by exploiting differences in the oxidation rates within a series of rare earth compounds containing the redox-active ligand [{2-(tBuN(O))C 6 H 4 CH 2 } 3 N] 3- . Using this method, a single-step separation factor up to 261 was obtained for the separation of a 50:50 yttrium-lutetium mixture. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Determination of Rare Earth Elements in Thai Monazite by Inductively Coupled Plasma and Nuclear Analytical techniques

    International Nuclear Information System (INIS)

    Busamongkol, Arporn; Ratanapra, Dusadee; Sukharn, Sumalee; Laoharojanaphand, Sirinart

    2003-10-01

    The inductively coupled plasma atomic emission spectroscopy (ICP-AES) for the determination of individual rare-earth elements (REE) was evaluated by comparison with instrumental neutron activation analysis (INAA) and x-ray fluorescence spectrometry (XRF). The accuracy and precision of INAA and ICP-AES were evaluated by using standard reference material IGS-36, a monazite concentrate. For INAA, the results were close to the certified value while ICP-AES were in good agreement except for some low concentration rare earth. The techniques were applied for the analysis of some rare earth elements in two Thai monazite samples preparing as the in-house reference material for the Rare Earth Research and Development Center, Chemistry Division, Office of Atoms for Peace. The analytical results obtained by these techniques were in good agreement with each other

  14. Electro-kinetic separation of rare earth elements using a redox-active ligand

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Huayi; Cole, Bren E.; Qiao, Yusen; Bogart, Justin A.; Cheisson, Thibault; Manor, Brian C.; Carroll, Patrick J.; Schelter, Eric J. [Department of Chemistry, University of Pennsylvania, Philadelphia, PA (United States)

    2017-10-16

    Purification of rare earth elements is challenging due to their chemical similarities. All of the deployed separation methods rely on thermodynamic properties, such as distribution equilibria in solvent extraction. Rare-earth-metal separations based on kinetic differences have not been examined. Herein, we demonstrate a new approach for rare-earth-element separations by exploiting differences in the oxidation rates within a series of rare earth compounds containing the redox-active ligand [{2-(tBuN(O))C_6H_4CH_2}{sub 3}N]{sup 3-}. Using this method, a single-step separation factor up to 261 was obtained for the separation of a 50:50 yttrium-lutetium mixture. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Study of alkaline-earth element complexes in anhydrous acetic acid

    International Nuclear Information System (INIS)

    Petit, N.

    1968-10-01

    We have studied the complexes of alkaline-earth elements in anhydrous acetic acid. Using glass-electrode potentiometry we have studied the titration of alkaline earth acetates with perchloric acid which is the strongest acid in anhydrous acetic acid. These titrations have shown that the basic strength of these acetates increases as follows: Mg 4 ); the mixed acetate-acid sulfate complex of barium: Ba (OAc)(HSO 4 ); the mixed acetate-chloride of barium: Ba (OAc)(Cl). (author) [fr

  16. The effect of acid rain stress on chlorophyll, peroxidase of the conservation of rare earth elements

    International Nuclear Information System (INIS)

    Chongling, Y.; Yetang, H.; Xianke, Y.; Shunzhen, F.; Shanql, W.

    1998-01-01

    Full text: Based on pot experiment, the effect of acid rain stress on chlorophyll, peroxidase of wheat, the relationship of them and the conservation of rare earth elements has been studied. The result showed: stress of acid rain resulted in decrease of chlorophyll content and a/b values, chlorophyll a/b value and chlorophyll content is positive correlation with pH value of acid rain: peroxidase activity was gradually rise with pH value decrease, which indirectly increased decomposition intensity of chlorophyll. Decreased content and a/b value of chlorophyll further speeded blade decay affected the transport and transformation of light energy and metabolism of carbohydrates. After being treated by rare earth elements content and pH value of chlorophyll and peroxidase activity could be relatively stable. Therefore, under lower acidity condition, rare earth elements can influence the effect of acid rain on chlorophyll and peroxidase activity of wheat

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  19. Utilisation of thorium in reactors

    Science.gov (United States)

    Anantharaman, K.; Shivakumar, V.; Saha, D.

    2008-12-01

    India's nuclear programme envisages a large-scale utilisation of thorium, as it has limited deposits of uranium but vast deposits of thorium. The large-scale utilisation of thorium requires the adoption of closed fuel cycle. The stable nature of thoria and the radiological issues associated with thoria poses challenges in the adoption of a closed fuel cycle. A thorium fuel based Advanced Heavy Water Reactor (AHWR) is being planned to provide impetus to development of technologies for the closed thorium fuel cycle. Thoria fuel has been loaded in Indian reactors and test irradiations have been carried out with (Th-Pu) MOX fuel. Irradiated thorium assemblies have been reprocessed and the separated 233U fuel has been used for test reactor KAMINI. The paper highlights the Indian experience with the use of thorium and brings out various issues associated with the thorium cycle.

  20. Geochemistry at the earth's surface. Movement of chemical elements

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Andreas [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Institut fuer Nukleare Entsorgung; Velde, Bruce D. [Ecole Normale Superieure, 75 - Paris (France). Lab. de Geologie

    2014-07-01

    Geochemistry at the surface of the earth is dominated by two somewhat antagonistic forces: chemical reactions which attempt to attain a steady state (equilibrium) and geological movement of materials in time and space which changes the parameters that control chemical equilibrium. Another aspect that is extremely important to earth surface geochemistry is the effect of plants on the chemical and physical stability of materials (soils). Plant systems in fact work against the normal chemical changes (loss of silica, potassium, etc.) and the normal physical changes (stabilizing fine grained materials (clays) in the surface zones to avoid erosion). Biological effects are clearly seen in redox effects in the various parts of the earth surface movement cycle; soil formation, stream transport, sedimentation. This book attempts to outline these different parameters and their interactions as they affect earth surface geochemistry in order to give a better understanding of movement and accumulation of elements at the surface of the earth.

  1. An improved ion-exchange separation of rare-earth elements for spectrographic analysis

    International Nuclear Information System (INIS)

    Jones, E.A.

    1978-01-01

    Rare-earth elements are separated from scandium and base metals by adsorption onto anion resin BIORAD AG1-X8 in the nitrate form from a mixture of 5 per cent 7M nitric acid and 95 per cent methanol. The yttrium subgroup is eluted with a mixture of 45 per cent 7M nitric acid and 55 per cent methanol, followed by elution of the cerium subgroup with 8M nitric acid. This separation facilitates the determination of the traces of the heavier yttrium subgroup of rare-earth elements

  2. Studies on rare earth elements in seawater and uptake by marine organisms

    International Nuclear Information System (INIS)

    Suzuki, H.; Koyanagi, T.; Saiki, M.

    1975-01-01

    The contents of rare earth elements in marine environmental samples were determined by neutron activation analysis to examine the existing state in coastal seawater and the concentration by marine organisms of the elements. Seawater was filtered through a Millipore filter GS (pore size 0.22 μm), before the analysis. Some of the seawater was treated with HC1 solution before filtration and some after filtration. Certain marine organisms were also analysed for determination of rare earth elements. These were: flounder (Paralichthys olivaceus); yellowtails (Seriola quinqueradiata); immature anchovy (Engraulis japonica); clams (Meretrix lusoria); green algae (Ulva pertusa); brown algae (Hizikia fusiforme, Sargassum fulvellum, Undaria pinnatifida). In the seawater without HC1 treatment before filtration, considerable amounts of the elements existed in residue on the filter, whereas in the seawater treated with HC1 before filtration, the greater part remained in the dissolved state. Concentration factors calculated from the contents of stable elements, therefore, are affected remarkably by the existing state of the elements in seawater. If only the dissolved state is assumed available for marine organisms, values one order higher are attained compared with the case where total amounts of the elements were used for the calculation. However, the contribution of the insoluble state seems to be not negligible with some organisms. The higher concentration factors for immature anchovy and clams observed in this study were considered to be caused by surface adsorption of elements in particulate form and also ingested sediment with high element concentration. (author)

  3. Evaluation of Rare Earth Element Extraction from North Dakota Coal-Related Feed Stocks

    Science.gov (United States)

    Laudal, Daniel A.

    The rare earth elements consist of the lanthanide series of elements with atomic numbers from 57-71 and also include yttrium and scandium. Due to their unique properties, rare earth elements are crucial materials in an incredible array of consumer goods, energy system components and military defense applications. However, the global production and entire value chain for rare earth elements is dominated by China, with the U.S. currently 100% import reliant for these critical materials. Traditional mineral ores including previously mined deposits in the U.S., however, have several challenges. Chief among these is that the content of the most critical and valuable of the rare earths are deficient, making mining uneconomical. Further, the supply of these most critical rare earths is nearly 100% produced in China from a single resource that is only projected to last another 10 to 20 years. The U.S. currently considers the rare earths market an issue of national security. It is imperative that alternative domestic sources of rare earths be identified and methods developed to produce them. Recently, coal and coal byproducts have been identified as one of these promising alternative resources. This dissertation details a study on evaluation of the technical and economic feasibility of rare earth element recovery from North Dakota lignite coal and lignite-related feedstocks. There were four major goals of this study: i) identify lignite or lignite-related feedstocks with total rare earth element content above 300 parts per million, a threshold dictated by the agency who funded this research as the minimum for economic viability, ii) determine the geochemistry of the feedstocks and understand the forms and modes of occurrence of the rare earth elements, information necessary to inform the development of extraction and concentration methods, iii) identify processing methods to concentrate the rare earth elements from the feedstocks to a target of two weight percent, a value

  4. Thorium utilization in power reactors

    International Nuclear Information System (INIS)

    Saraceno; Marcos.

    1978-10-01

    In this work the recent (prior to Aug, 1976) literature on thorium utilization is reviewed briefly and the available information is updated. After reviewing the nuclear properties relevant to the thorium fuel cycle we describe briefly the reactor systems that have been proposed using thorium as a fertile material. (author) [es

  5. Recovering of thorium contained in wastes from Thorium Purification Plant

    International Nuclear Information System (INIS)

    Brandao Filho, D.; Hespanhol, E.C.B.; Baba, S.; Miranda, L.E.T.; Araujo, J.A. de.

    1992-08-01

    A study has been developed in order to establish a chemical process for recovering thorium from wastes produced at the Thorium Purification Plant of the Instituto de Pesquisas Energeticas e Nucleares. The recovery of thorium in this process will be made by means of solvent extraction technique. Solutions of TBP/Varsol were employed as extracting agent during the runs. The influence of thorium concentration in the solution, aqueous phase acidity, volume ratio of the phases, percentage of TBP/Varsol and the contact time of the phases on the extraction of thorium and lanthanides was determined. (author)

  6. Determination of rare-earth elements in Luna 16 regolith sample by chemical spectral method

    Science.gov (United States)

    Stroganova, N. S.; Ryabukhin, V. A.; Laktinova, N. V.; Ageyeva, L. V.; Galkina, I. P.; Gatinskaya, N. G.; Yermakov, A. N.; Karyakin, A. V.

    1974-01-01

    An analysis was made of regolith from layer A of the Luna 16 sample for rare earth elements, by a chemical spectral method. Chemical and ion exchange concentrations were used to determine the content of 12 elements and Y at the level 0.001 to 0.0001 percent with 10 to 15 percent reproducibility of the emission determination. Results within the limits of reproducibility agree with data obtained by mass spectra, activation, and X-ray fluorescent methods.

  7. Light shifts and magic wavelengths for heavy alkaline earth elements : Ba and Ra

    NARCIS (Netherlands)

    Dammalapati, U.; Santra, B.; Willmann, L.

    2012-01-01

    In this paper, we investigate light shifts of heavy alkaline earth elements barium (Ba) and radium (Ra), which are interesting for optical lattice clocks and for permanent electric dipole moment searches. Detailed knowledge is required in the design of efficient loading of atoms from a

  8. Rare-earth elements and uranium in phosphatic nodules from the continental margins of India

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.; Rao, B.R.; Rao, K.M.; Rao, Ch.M.

    and rare-earth elements (REEs) by inductively coupled plasma-mass spectrometry (ICP-MS). Total REE contents are very low (8-21 ppm) in western continental margin nodules and only slightly in eastern continental margin nodules (maximum is 42 ppm). REE...

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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...

  11. A CONTRIBUTION TO THE RESEARCH ON RARE EARTH ELEMENTS IN SEDIMENTARY ROCKS

    Directory of Open Access Journals (Sweden)

    Josip Crnički

    1989-12-01

    Full Text Available The main features of the geochemistry of rare earth elements (REE, REE mineralogy and the REE i contents and distributions in sedimentary rocks are presented. A new classification of REE minerals as well as a new systematic order of the REE behaviour in sedimentology is introduced and explained.

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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...

  15. Geochemistry of some rare earth elements in groundwater, Vierlingsbeek, the Netherlands

    NARCIS (Netherlands)

    Janssen RPT; Verweij W; Versteegh JFM; LWD

    1997-01-01

    Speciation calculations were carried out on groundwater samples to shed more light on the chemical processes of rare earth elements (REE). These samples were taken from seven boreholes at several depths near the drinking water pumping station, Vierlingsbeek, The Netherlands. Complexation and

  16. Maximum Permissible Concentrations and Negligible Concentrations for Rare Earth Elements (REEs)

    NARCIS (Netherlands)

    Sneller FEC; Kalf DF; Weltje L; Wezel AP van; CSR

    2000-01-01

    In this report maximum permissible concentrations (MPCs) and negligible concentrations (NCs) are derived for Rare Earth Elements (REEs), which are also known as lanthanides. The REEs selected for derivation of environmental risk limits in this report are Yttrium (Y), Lanthanum (La), Cerium (Ce),

  17. Thermalization of different alkali and alkali-earth elements at the TRI mu P facility

    NARCIS (Netherlands)

    Shidling, P. D.; Giri, G. S.; van der Hoek, D. J.; Jungmann, K.; Kruithof, W. L.; Onderwater, C. J. G.; Santra, B.; Sohani, M.; Versolato, O. O.; Willmann, L.; Wilschut, H. W.

    2010-01-01

    Radioactive isotopes produced by the in-flight method are converted into low-energy ions with a thermal ionizer (TI) ion catcher, the operation of which is based on a hot cavity ion source. The extraction efficiency of the TI for different alkali and alkali-earth elements has been studied and

  18. Correlations fo Sc, rare earths and other elements in selected rock samples from Arrua-i

    International Nuclear Information System (INIS)

    Facetti, J.F.; Prats, M.

    1972-01-01

    The Sc and Eu contents in selected rocks samples from the stock of Arrua-i have been determined and correlations established with other elements and with the relative amount of some rare earths. These correlations suggest metasomatic phenomena for the formation of the rock samples

  19. Yttrium separation of Xenotime waste in Pitinga (Brazil), in order to obtain rare earth elements

    International Nuclear Information System (INIS)

    Melo.

    1996-01-01

    The xenotime (YPO 4 and rare earth elements) found in the mine of Pitinga, Amazonas State, Brazil, has its origin in a primal depository ('eluvio' kind) of cassiterite, having considerable quantities of zirconite, ilmenite, topaz and niobates-tantalates. This xenotime has different characteristics in relation of the depositories that exist in other countries for presenting more concentration of rare earth heavy oxides. The mineralization of this cassiterite is problematic, because of the high level of radioactive elements. In the present work, we will process only the xenotime. The separation of rare earth elements is very difficult due to their great chemical similarity. For a more exactly determination, it is necessary to separate them at least of the macron constituents of the sample. As the Yttrium is considerate one of the rare earth elements, due to its chemical similarity, we can understand the difficulty of a chemical separation, mainly when this one is also a macro constituent of the sample, as in the case of xenotime. The process of separation will be based on the little difference that exists between the constants of complexation and the fluoride. (authors). 5 refs., 1 fig., 2 tabs

  20. Variation of Rare Earth Elements (REEs) in the Sulu and Celebes ...

    African Journals Online (AJOL)

    This study provides a dataset of rare earth elements (REEs) in the seawater of Sulu and Celebes Seas of Malaysian waters during the PMSE 09' expedition, which was conducted to define the pattern of REEs in both seas. Samples were collected, filtered and pre-concentrated on-board ship then analyzed by using ICP-MS.

  1. [Spectroscopic Research on Slag Nanocrystal Glass Ceramics Containing Rare Earth Elements].

    Science.gov (United States)

    Ouyang, Shun-li; Li, Bao-wei; Zhang, Xue-feng; Jia, Xiao-lin; Zhao, Ming; Deng, Lei-bo

    2015-08-01

    The research group prepared the high-performance slag nanocrystal glass ceramics by utilizing the valuable elements of the wastes in the Chinese Bayan Obo which are characterized by their symbiotic or associated existence. In this paper, inductively coupled plasma emission spectroscopy (ICP), X-ray diffraction (XRD), Raman spectroscopy (Raman) and scanning electron microscopy (SEM) are all used in the depth analysis for the composition and structure of the samples. The experiment results of ICP, XRD and SEM showed that the principal crystalline phase of the slag nanocrystal glass ceramics containing rare earth elements is diopside, its grain size ranges from 45 to 100 nm, the elements showed in the SEM scan are basically in consistent with the component analysis of ICP. Raman analysis indicated that its amorphous phase is a three-dimensional network structure composed by the structural unit of silicon-oxy tetrahedron with different non-bridging oxygen bonds. According to the further analysis, we found that the rare earth microelement has significant effect on the network structure. Compared the nanocrystal slag glass ceramic with the glass ceramics of similar ingredients, we found that generally, the Raman band wavenumber for the former is lower than the later. The composition difference between the glass ceramics and the slag nanocrystal with the similar ingredients mainly lies on the rare earth elements and other trace elements. Therefore, we think that the rare earth elements and other trace elements remains in the slag nanocrystal glass ceramics have a significant effect on the network structure of amorphous phase. The research method of this study provides an approach for the relationship among the composition, structure and performance of the glass ceramics.

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

    International Nuclear Information System (INIS)

    Pothen, Frank; Fink, Kilian

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-04-20

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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Timothy Ault

    2015-03-01

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

  6. Sustainability of rare earth elements chain: from production to food - a review.

    Science.gov (United States)

    Turra, Christian

    2018-02-01

    Rare earth elements (REE) are a group of chemical elements that include lanthanoids (lanthanum to lutetium), scandium and yttrium. In the last decades, the REE demand in the industry and other areas has increased significantly. In general, REE have shown low concentrations in soils, plants, water and atmosphere, but they may accumulate in such environments due to anthropogenic inputs. In areas where there is REE contamination, the slow accumulation of these elements in the environment could become problematic. Many studies have shown environmental areas contaminated with REE and their toxic effects. Thus, it is important to review, in order to improve the current understanding of these elements in the environment, showing the effects of REE exposure in mining, soil, water, plants and food. Besides, there are few suppliers and a limited quantity of these elements in the world. This paper suggests options to improve the sustainability management of REE chain.

  7. Simultaneous determination of uranium and thorium with Arsenazo III by second-derivative spectrophotometry

    International Nuclear Information System (INIS)

    Kuroda, Rokuro; Kurosaki, Mayumi; Hayashibe, Yutaka; Ishimaru, Satomi

    1990-01-01

    A derivative spectrophotometric method has been developed for the simultaneous determination of microgram quantities of uranium and thorium with Arsenazo III in hydrochloric acid medium. The second-derivative absorbances of the uranium and thorium Arsenazo III complexes at 679.5 and 684.4 nm are used for their quantification. Uranium and thorium, both in the range 0.1-0.7 μg/ml have been determined simultaneously with good precision. The procedure does not require separation of uranium and thorium, and allows the determination of both metals in the presence of alkaline-earth metals and zirconium, but lanthanides interfere. (author)

  8. The thorium fuel cycle

    International Nuclear Information System (INIS)

    Merz, E.R.

    1977-01-01

    The utilization of the thorium fuel cycle has long since been considered attractive due to the excellent neutronic characteristics of 233 U, and the widespread and cheap thorium resources. Although the uranium ore as well as the separative work requirements are usually lower for any thorium-based fuel cycle in comparison to present uranium-plutonium fuel cycles of thermal water reactors, interest by nuclear industry has hitherto been marginal. Fast increasing uranium prices, public reluctance against widespread Pu-recycling and expected retardations for the market penetration of fast breeders have led to a reconsideration of the thorium fuel cycle merits. In addition, it could be learned in the meantime that problems associated with reprocessing and waste handling, but particularly with a remote refabrication of 233 U are certainly not appreciably more difficult than for Pu-recycling. This may not only be due to psychological constraints but be based upon technological as well as economical facts, which have been mostly neglected up till now. In order to diversify from uranium as a nuclear energy source it seems to be worthwhile to greatly intensify efforts in the future for closing the Th/ 233 U fuel cycle. HTGR's are particularly promising for economic application. However, further R and D activites should not be solely focussed on this reactor type alone. Light and heavy-water moderated reactors, as well as even fast breeders later on, may just as well take advantage of a demonstrated thorium fuel cycle. A summary is presented of the state-of-the-art of Th/ 233 U-recycling technology and the efforts still necessary to demonstrate this technology all the way through to its industrial application

  9. Thorium content of a mineral ore from Morro do Ferro by fission track technique

    International Nuclear Information System (INIS)

    Oliveira, C.A.N. de.

    1980-10-01

    The feasibility to determine thorium concentrations by fission track technique in samples of mineral ore has been demonstrated. The literature registers only the application of the fission track technique to mineral ore in the case where the fissionable element is uranium. The technique was applied to determine the thorium concentration of an ore sample from Morro do Ferro, taking advantage of the high thorium to uranium ratio in that mineral. The sample analysed presented a thorium concentration of 2467 +- 400 mg Th/Kg ore. The so called wet method was adopted by using the Bayer made Makrofol KG 10μm thick, as the detector foil, immersed in the thorium solution. The technique is also useful to determine thorium concentrations in environmental samples because of the following aspects: high sensitivity; fast chemical separation of interfering elements; low cost; and operational simplicity. (Author) [pt

  10. Activation analysis of rare-earth elements in opium and cannabis samples

    International Nuclear Information System (INIS)

    Henke, G.

    1977-01-01

    Rare-earth concentrations in 65 Opium, Cannabis and Cannabis resin samples seized from various parts of the world were determined by destructive NAA. Because of the greater concentrations of Ca, P, K, Fe, Na and Si in plant materials, rare-earth elements were isolated after neutron irradiation and determined by gamma-spectrometry. The main steps of the method are: Preashing of 1 g Cannabis resin, 2.5 g Cannabis or 7.5 g Opium, respectively, in quartz ampoules (5 h, 500 deg C). Neutron irradiation, 24 h at 5x10 13 n cm -2 sec -1 . Cooling period 2-3 days. After addition of 0.1 μCi 139 Ce and rare-earth carriers wet ashing of irradiated samples with H 2 SO 4 /HNO 3 , followed by alternate addition of HNO 3 and H 2 O 2 (30%). Precipitation and removal of silicates, precipitation of fluorides, precipitation of hydroxides. Dissolution of hydroxides in HCl. Extraction with di-(2-ethylhexyl)phosphate (DEHP)/toluene and twice back-extraction of rare earths, gamma-spectrometry of HCl phase. Due to sample activity and half-life of nuclides, three measurements were made on each sample: 2 days (for La, Sm, Gd, Ho, Er, Yb); 14 days (for Nd, Lu) and 30 days after irradiation (for Ce, Eu, Tb). Great variations in absolute element concentrations, but only small significant differences of rare earth concentration ratios were found, indicating inconsiderable biogeochemical fractionation. The mean values of these ratios correspond to the relative abundances of the rare earths in the upper continental earth's crust. (T.G.)

  11. Uranium-thorium and rare earth migration in granitic uranium deposits: comparison test with high level radioactive wastes in underground disposal

    International Nuclear Information System (INIS)

    Menager, M.T.

    1991-01-01

    The dispersion of U, Th and REE from a U-vein type deposit, localized in an intragranitic vein, through the surrounding host rock has been characterized by combining petrological, mineralogical, geochemical (major and trace elements, radiogenic isotopes) studies. The different stages of hydrothermal alteration, including those leading to changes in the major or trace elements concentrations have been identified. The distances over which U, Th and REE have migrated are estimated and correlated to the main water/rock interaction processes. The role of co-precipitation with secondary minerals in the retention of these elements is stressed. These processes are considered as analogous to those which could take place around a radioactive waste repository in a similar rock formation. The main geochemical implications of this work for the safety assessment of such a disposal are discussed. 7 figs., 27 refs

  12. Environmental Characteristics of Carbonatite and Alkaline Intrusion-related Rare Earth Element (REE) Deposits

    Science.gov (United States)

    Seal, R. R., II; Piatak, N. M.

    2017-12-01

    Carbonatites and alkaline intrusions are important sources of REEs. Environmental risks related to these deposit types have been assessed through literature review and evaluation of the geochemical properties of representative samples of mill tailings and their leachates. The main ore mineral in carbonatite deposits is bastnasite [(Ce,La)(CO3)F], which is found with dolomite and calcite ( 65 %), barite (20 - 25 %), plus a number of minor accessory minerals including sulfides such as galena and pyrite. Generally, alkaline intrusion-related REE deposits either occur in layered complexes or with dikes and veins cutting alkaline intrusions. Such intrusions have a more diverse group of REE ore minerals that include fluorcarbonates, oxides, silicates, and phosphates. Ore also can include minor calcite and iron (Fe), lead (Pb), and zinc (Zn) sulfides. The acid-generating potential of both deposit types is low because of a predominance of carbonate minerals in the carbonatite deposits, the presence of feldspars and minor calcite in alkaline intrusion-related deposits, and to only minor to trace occurrence of potentially acid-generating sulfide minerals. Both deposit types, however, are produced by igneous and hydrothermal processes that enrich high-field strength, incompatible elements, which typically are excluded from common rock-forming minerals. Elements such as yttrium (Y), niobium Nb), zirconium (Zr), hafnium (Hf), tungsten (W), titanium (Ti), tantalum (Ta), scandium (Sc), thorium (Th), and uranium (U) can be characteristic of these deposits and may be of environmental concern. Most of these elements, including the REEs, but with the exception of U, have low solubilities in water at the near-neutral pH values expected around these deposits. Mill tailings from carbonatite deposits can exceed residential soil and sediment criteria for Pb, and leachates from mill tailings can exceed drinking water guidelines for Pb. The greatest environmental challenges, however, are

  13. Concentrations and health risk assessment of rare earth elements in vegetables from mining area in Shandong, China.

    Science.gov (United States)

    Zhuang, Maoqiang; Zhao, Jinshan; Li, Suyun; Liu, Danru; Wang, Kebo; Xiao, Peirui; Yu, Lianlong; Jiang, Ying; Song, Jian; Zhou, Jingyang; Wang, Liansen; Chu, Zunhua

    2017-02-01

    To investigate the concentrations of rare earth elements in vegetables and assess human health risk through vegetable consumption, a total of 301 vegetable samples were collected from mining area and control area in Shandong, China. The contents of 14 rare earth elements were determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The total rare earth elements in vegetables from mining and control areas were 94.08 μg kg -1 and 38.67 μg kg -1 , respectively, and the difference was statistically significant (p rare earth elements concentration (984.24 μg kg -1 and 81.24 μg kg -1 for mining and control areas, respectively) and gourd vegetable had the lowest rare earth elements concentration (37.34 μg kg -1 and 24.63 μg kg -1 for mining and control areas, respectively). For both areas, the rare earth elements concentration in vegetables declined in the order of leaf vegetable > taproot vegetable > alliaceous vegetable > gourd vegetable. The rare earth elements distribution patterns for both areas were characterized by enrichment of light rare earth elements. The health risk assessment demonstrated that the estimated daily intakes (0.69 μg kg -1 d -1 and 0.28 μg kg -1 d -1 for mining and control areas, respectively) of rare earth elements through vegetable consumption were significantly lower than the acceptable daily intake (70 μg kg -1 d -1 ). The damage to adults can be neglected, but more attention should be paid to the effects of continuous exposure to low levels of rare earth elements on children. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Trace elements and rare earth elements in wet deposition of Lijiang, Mt. Yulong region, southeastern edge of the Tibetan Plateau.

    Science.gov (United States)

    Guo, Junming; Kang, Shichang; Huang, Jie; Sillanpää, Mika; Niu, Hewen; Sun, Xuejun; He, Yuanqing; Wang, Shijing; Tripathee, Lekhendra

    2017-02-01

    In order to investigate the compositions and wet deposition fluxes of trace elements and rare earth elements (REEs) in the precipitation of the southeastern edge of the Tibetan Plateau, 38 precipitation samples were collected from March to August in 2012 in an urban site of Lijiang city in the Mt. Yulong region. The concentrations of most trace elements and REEs were higher during the non-monsoon season than during the monsoon season, indicating that the lower concentrations of trace elements and REEs observed during monsoon had been influenced by the dilution effect of increased precipitation. The concentrations of trace elements in the precipitation of Lijiang city were slightly higher than those observed in remote sites of the Tibetan Plateau but much lower than those observed in the metropolises of China, indicating that the atmospheric environment of Lijiang city was less influenced by anthropogenic emissions, and, as a consequence, the air quality was still relatively good. However, the results of enrichment factor and principal component analysis revealed that some anthropogenic activities (e.g., the increasing traffic emissions from the rapid development of tourism) were most likely important contributors to trace elements, while the regional/local crustal sources rather than anthropogenic activities were the predominant contributors to the REEs in the wet deposition of Lijiang city. Our study was relevant not only for assessing the current status of the atmospheric environment in the Mt. Yulong region, but also for specific management actions to be implemented for the control of atmospheric inputs and the health of the environment for the future. Copyright © 2016. Published by Elsevier B.V.

  15. Realizing the therapeutic potential of rare earth elements in designing nanoparticles to target and treat glioblastoma.

    Science.gov (United States)

    Lu, Victor M; McDonald, Kerrie L; Townley, Helen E

    2017-10-01

    The prognosis of brain cancer glioblastoma (GBM) is poor, and despite intense research, there have been no significant improvements within the last decade. This stasis implicates the need for more novel therapeutic investigation. One such option is the use of nanoparticles (NPs), which can be beneficial due to their ability to penetrate the brain, overcome the blood-brain barrier and take advantage of the enhanced permeation and retention effect of GBM to improve specificity. Rare earth elements possess a number of interesting natural properties due to their unique electronic configuration, which may prove therapeutically advantageous in an NP formulation. The underexplored exciting potential for rare earth elements to augment the therapeutic potential of NPs in GBM treatment is discussed in this review.

  16. Evolution of Mg-5Al-0.4Mn microstructure after rare earth elements addition

    Directory of Open Access Journals (Sweden)

    A. Żydek

    2011-04-01

    Full Text Available Mg-5Al-0.4Mn-xRE (x = 0, 1, 2, 3 wt.% magnesium alloys were prepared successfully by casting method. The microstructure wasinvestigated by light microscopy. The influence of rare earth (RE elements on the area fraction of eutectic was analysed. The obtainedresults revealed that the as-cast Mg-5Al-0.4Mn alloy consist of α - Mg matrix and eutectic α + γ (where γ is Mg17Al12. However, whilerare earth elements were added to the Mg-Al type alloy, Al11RE3 precipitates were formed. The amount of the Al11RE3 precipitatesincreased with increasing addition of RE, but the amount of γ - Mg17Al12 decreased.

  17. Separation of traces of traces of trans-plutonium elements in weight quantities of rare earths

    International Nuclear Information System (INIS)

    SORET, Christian

    1969-08-01

    The author reports the separation of trans-plutonium elements and their dosing in a mixture of fission products. In some situations dosing is performed on both rare earths and trans-plutonium elements. The chemical separation process is a chromatographic method of exchange on an anionic resin in concentrated lithium chloride. He proposes a brief overview of separation processes, describes the separation mechanism, and then reports preliminary studies of the influence of increasing quantities of rare earths and the influence of increasing heights of resin bed in order to determine the best conditions of separation. He describes the preparation of resin and of the column, the introduction of the fixing solution at the top of the column, the preparation of lithium chloride solutions. He presents the adjustment and measurement devices, and the calculation of the resin minimum volume. Results are then presented and discussed. The operation mode is addressed: devices, reagents, preparation techniques (preparation of lithium chloride solutions) [fr

  18. Spectral and thermal behaviours of rare earth element complexes with 3,5-dimethoxybenzoic acid

    Directory of Open Access Journals (Sweden)

    JANUSZ CHRUŚCIEL

    2003-10-01

    Full Text Available The conditions for the formation of rare earth element 3,5-dimethytoxybenzoates were studied and their quantitative composition and solubilities in water at 293 K were determined. The complexes are anhydrous or hydrated salts and their solubilities are of the orders of 10-5 – 10-4 mol dm-3. Their FTIR, FIR and X-ray spectra were recorded. The compounds were also characterized by thermogravimetric studies in air and nitrogen atmospheres and by magnetic measurements. All complexes are crystalline compounds. The carboxylate group in these complexes is a bidentate, chelating ligand. On heating in air to 1173 K, the 3,5-dimethoxybenzoates of rare earth elements decompose in various ways. The hydrated complexes first dehydrate to form anhydrous salts which then decompose in air to the oxides of the respective metals while in nitrogen to mixtures of carbon and oxides of the respective metals. The complexes are more stable in air than in nitrogen.

  19. Torium partition and rare earths studies in particles from Morro de Ferro region, Pocos de Caldas, MG

    International Nuclear Information System (INIS)

    Carlos, M.T.

    1988-01-01

    The researchs made in Radioisotopes Laboratory of IB - UFRJ (Biophysics Institute - Federal Rio de Janeiro University) during 1986 that included in the research program the geochemical transport in Morro de Ferro project was related. The thorium and rare earths elements association was characterized in the geochemical aspect using chemical fractionation methods through the experiments of selective lixiviation. (L.M.J.) [pt

  20. The phosphorus fertilizer production as a source of rare-earth elements pollution of the environment

    International Nuclear Information System (INIS)

    Volokh, A.A.; Gorbunov, A.V.; Revich, B.A.; Gundorina, S.F.; Frontas'eva, M.V.; Chen Sen Pal.

    1989-01-01

    This paper considers some peculiarities of the production of phosphorus fertilizers from the point of view of the pollution of the environment with rare-earth elements. The principal possibility is demonstrated of the determination of the influence of a given type of production on the environment by measuring the change in the rare-arth elements interrelationship in the show. The main source of industrial dust is identified. The distribution of pollutants in dependence on the size of aerosol particles is given. The data on the concentrations of the pollutants in agricultural plants, employees hair and hair of local residents are also reported. 8 refs.; 4 figs.; 4 tabs

  1. Impulsive penetration of filamentary plasma elements into the magnetospheres of the earth and Jupiter

    Science.gov (United States)

    Lemaire, J.

    1977-01-01

    Assuming that the solar wind plasma is usually nonuniform over distances of 10,000 km or less, it is shown that filamentary plasma elements stretched out from the sun can penetrate impulsively and become engulfed into the magnetosphere. The diamagnetic effects associated with these plasma inhomogeneities are observed in outer magnetospheres and magnetosheaths as dips or directional discontinuities in the magnetic field measurements. From the mean penetration distances of these diamagnetic plasma elements one can deduce a mean deceleration time, as well as an approximate value of the integrated Pedersen conductivity in the polar cusp of the earth and Jupiter.

  2. Neutron activation analysis of rare earths and some other elements in material of geochemical interest

    International Nuclear Information System (INIS)

    Brunfelt, A.O.

    1975-01-01

    ngle-element methods for the determination by neutron activation analysis of antimony, chromium, phosphorus, selenium and silver in international geochemical standard rocks, and the determination of rare earth elements i in standard rocks and apatites are described and discussed in twelve previously published papers, and in an eighteen page summary. Chemical separationtechniques are also discussed and the results are compared with previously obtained results with the same standard rocks. The accuracy of neutron activation analysis is discussed in comparison with isotope dilution mass spectroscopy, atomic absorption, gas chromatography and spark source mass spectrometry. (JIW)

  3. ELECTROLYSIS OF THORIUM AND URANIUM

    Science.gov (United States)

    Hansen, W.N.

    1960-09-01

    An electrolytic method is given for obtaining pure thorium, uranium, and thorium-uranium alloys. The electrolytic cell comprises a cathode composed of a metal selected from the class consisting of zinc, cadmium, tin, lead, antimony, and bismuth, an anode composed of at least one of the metals selected from the group consisting of thorium and uranium in an impure state, and an electrolyte composed of a fused salt containing at least one of the salts of the metals selected from the class consisting of thorium, uranium. zinc, cadmium, tin, lead, antimony, and bismuth. Electrolysis of the fused salt while the cathode is maintained in the molten condition deposits thorium, uranium, or thorium-uranium alloys in pure form in the molten cathode which thereafter may be separated from the molten cathode product by distillation.

  4. The comparative distribution of thorium and plutonium in human tissues

    International Nuclear Information System (INIS)

    Singh, Narayani P.; Shawki Amin Ibrahim; Cohen, Norman; Wrenn, McDonald E.

    1978-01-01

    Thorium is the most chemically and biologically similar natural element to the manmade element plutonium. Both are actinides, and for both the most stable valency state is +4, and solubility in natural body fluids is low. They are classified together in ICRP Lung Model. The present paper deals with the question of whether or not the analogy between the two actinides in terms of deposition and retention in human tissues is a good one. Preliminary results on the thorium contents ( 228,230 Th and 232 Th) of three sets of human tissues from a western U.S. town containing a uranium tailings pile are compared with the reported values of plutonium content of human tissues from the general populations who are exposed to environmental plutonium from fallout of nuclear detonations. Samples were taken at autopsy where sudden death had occurred. For the three isotopes of thorium, the ratio of the content of each (pCi/organ, normalized by organ weight to ICRP Reference Man) in lung to lymph nodes varies from 2-25 for individuals with a mean of 8; this is similar to that we infer from the literature for 239 , 240 Pu which suggests a ratio of lung to lymph nodes with a mean of approximately 7. However, the relative thorium contents of lung and liver are dissimilar, lung/liver for thorium being 3.5 and for plutonium 0.2 to 0.1. Similarly, the ratios of thorium and plutonium content of liver and bone vary significantly; the ratio for thorium is 0.1 and for plutonium 0.8 to 0.5. The most significant observation at this stage is that the relative accumulation of thorium in human liver is much less than that of plutonium. Some of the plausible reasons will be discussed. (author)

  5. Study on the extraction of rare earth elements in liquid bismuth

    International Nuclear Information System (INIS)

    Harada, M.; Adachi, M.; Kai, Y.; Koike, K.

    1987-01-01

    Three factors, which are important for the extraction of rare earth elements in liquid bismuth - molten salt system, were studied, i. e., the equilibrium distribution of neodymium, samarium and bismuth between molten LiCl - liquid Bi-Li alloys, the extraction rate of rare earths, and the characteristics of the extractor with drop dispersion. The rare earth elements were extracted through redox reactions. In high range of Li-mole fraction in the alloy phase, X Li , the distribution of neodymium and bismuth in the salt phase markedly increased as X Li increased. The anomalous increase is attributed to the formation of the compound comprised of Nd, Li, Bi and oxygen in the salt phase. The redox reaction processes were very fast and the extraction rates for rare earths are controlled by the diffusion processes of the solute and the metallic lithium. The process for the formation of liquid metal drops in the continuous phase is predictable from semiempirical correlations reported for aqueous solution - organic solvent systems. The height of droplet bed being accumulated on drop settling portion is predictable from the coalescence time of single drop to a flat metal interface. The coalescence of metal drop to clean interface was very fast. The extractor type of liquid metal dispersion in molten salt is suitable for the extraction process in the fuel reprocessing of MSR or MSBR. (author)

  6. Modeling viscoelastic deformation of the earth due to surface loading by commercial finite element package - ABAQUS

    Science.gov (United States)

    Kit Wong, Ching; Wu, Patrick

    2017-04-01

    Wu (2004) developed a transformation scheme to model viscoelatic deformation due to glacial loading by commercial finite element package - ABAQUS. Benchmark tests confirmed that this method works extremely well on incompressible earth model. Bangtsson & Lund (2008),however, showed that the transformation scheme would lead to incorrect results if compressible material parameters are used. Their study implies that Wu's method of stress transformation is inadequate to model the load induced deformation of a compressible earth under the framework of ABAQUS. In light of this, numerical experiments are carried out to find if there exist other methods that serve this purpose. All the tested methods are not satisfying as the results failed to converge through iterations, except at the elastic limit. Those tested methods will be outlined and the results will be presented. Possible reasons of failure will also be discussed. Bängtsson, E., & Lund, B. (2008). A comparison between two solution techniques to solve the equations of glacially induced deformation of an elastic Earth. International journal for numerical methods in engineering, 75(4), 479-502. Wu, P. (2004). Using commercial finite element packages for the study of earth deformations, sea levels and the state of stress. Geophysical Journal International, 158(2), 401-408.

  7. Rationally designed mineralization for selective recovery of the rare earth elements

    OpenAIRE

    Hatanaka, Takaaki; Matsugami, Akimasa; Nonaka, Takamasa; Takagi, Hideki; Hayashi, Fumiaki; Tani, Takao; Ishida, Nobuhiro

    2017-01-01

    The increasing demand for rare earth (RE) elements in advanced materials for permanent magnets, rechargeable batteries, catalysts and lamp phosphors necessitates environmentally friendly approaches for their recovery and separation. Here, we propose a mineralization concept for direct extraction of RE ions with Lamp (lanthanide ion mineralization peptide). In aqueous solution containing various metal ions, Lamp promotes the generation of RE hydroxide species with which it binds to form hydrop...

  8. Finite Element Limit Analysis of Active Earth Pressure in Nonhomogeneous soils

    Directory of Open Access Journals (Sweden)

    Peyman Hamidi

    2016-01-01

    Full Text Available Limit analysis is a useful method to calc1ulate bearing capacity of footings, earth pressure of retaining walls, stability of slopes and excavations. In recent years, many efforts have been focused on stability problems of geotechnical structures with the limit analysis method. The limit analysis method includes the upper and lower bound theorems. By using the two theorems, the range, in which the true solution falls, can be found. In this paper upper bound finite element limit analysis is used for calculate active earth force on retaining walls in non-homogeneous soils. Elements with linear strain rates cause to eliminate the necessity of velocity discontinuities between the elements. Nonlinear programming based on second order cone programming (SOCP ,which has good conformity with Mohr-Coulomb criterion used in this paper. The sensitivity of active earth force against backfill surcharge (q, soil layers cohesion (Ci, soil layers unit weight (γi and friction angle between soil and wall (δi is surveyed.

  9. Chemical speciation and bioavailability of rare earth elements (REEs) in the ecosystem: a review.

    Science.gov (United States)

    Khan, Aysha Masood; Bakar, Nor Kartini Abu; Bakar, Ahmad Farid Abu; Ashraf, Muhammad Aqeel

    2017-10-01

    Rare earths (RE), chemically uniform group of elements due to similar physicochemical behavior, are termed as lanthanides. Natural occurrence depends on the geological circumstances and has been of long interest for geologist as tools for further scientific research into the region of ores, rocks, and oceanic water. The review paper mainly focuses to provide scientific literature about rare earth elements (REEs) with potential environmental and health effects in understanding the research. This is the initial review of RE speciation and bioavailability with current initiative toward development needs and research perceptive. In this paper, we have also discussed mineralogy, extraction, geochemistry, analytical methods of rare earth elements. In this study, REEs with their transformation and vertical distribution in different environments such as fresh and seawater, sediments, soil, weathering, transport, and solubility have been reported with most recent literature along key methods of findings. Speciation and bioavailability have been discussed in detail with special emphasis on soil, plant, and aquatic ecosystems and their impacts on the environment. This review shows that REE gained more importance in last few years due to their detrimental effects on living organisms, so their speciation, bioavailability, and composition are much more important to evaluate their health risks and are discussed thoroughly as well.

  10. [Rare earth elements contents and distribution characteristics in nasopharyngeal carcinoma tissue].

    Science.gov (United States)

    Zhang, Xiangmin; Lan, Xiaolin; Zhang, Lingzhen; Xiao, Fufu; Zhong, Zhaoming; Ye, Guilin; Li, Zong; Li, Shaojin

    2016-03-01

    To investigate the rare earth elements(REEs) contents and distribution characteristics in nasopharyngeal carcinoma( NPC) tissue in Gannan region. Thirty patients of NPC in Gannan region were included in this study. The REEs contents were measured by tandem mass spectrometer inductively coupled plasma(ICP-MS/MS) in 30 patients, and the REEs contents and distribution were analyzed. The average standard deviation value of REEs in lung cancer and normal lung tissues was the minimum mostly. Light REEs content was higher than the medium REEs, and medium REEs content was higher than the heavy REEs content. REEs contents changes in nasopharyngeal carcinoma were variable obviously, the absolute value of Nd, Ce, Pr, Gd and other light rare earth elements were variable widely. The degree of changes on Yb, Tb, Ho and other heavy rare earth elements were variable widely, and there was presence of Eu, Ce negative anomaly(δEu=0. 385 5, δCe= 0. 523 4). The distribution characteristic of REEs contents in NPC patients is consistent with the parity distribution. With increasing atomic sequence, the content is decline wavy. Their distribution patterns were a lack of heavy REEs and enrichment of light REEs, and there was Eu , Ce negative anomaly.

  11. Characteristics and genesis of Rare Earth Element (REE) in western Indonesia

    Science.gov (United States)

    Handoko, A. D.; Sanjaya, E.

    2018-02-01

    Rare Earth Element (REE) has unique properties that have been used in many hightech applications. The demand of REE increased recently in the world due to its special properties. Although REE concentration in the crust is higher than gold, economically viable deposits are still rare. Reduction of REE exports by China cause increased prices of REE. Due to this condition, exploration of potential REE mines emerged. Indonesia also participates in this phenomenon, and explore the possibility of REE mines in its area. This review will discuss the characteristics and genesis of REE and its occurrence in western Indonesia; focused in Sumatera, Tin Island, and Kalimantan. The review is done based on literature research from several resources about characteristics of rare earth element in general and in the given area. The research shows that the potential REE mines can be found in several different locations in Indonesia, such as Tin Island, Sumatera, and Kalimantan. Most of them are composed of monazite, zircon, and xenotime as rare earth minerals. Monazite iss known for its elevated number of radioactive elements, so study about radioactive content and more environment friendly ore processing becomes compulsory.

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

    Science.gov (United States)

    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.

  13. Speciation of rare earth elements in different types of soils in China

    International Nuclear Information System (INIS)

    Wang Lijun; Zhang Shen; Gao Xiaojiang; Liu Shujuan

    1997-01-01

    Contents, distribution patterns, physical and chemical speciation of rare earth elements (REEs) in laterite (tropical zone), red earth (middle subtripical earth), yellow brown soil (Northern subtripical earth), cinnamon soil (warm temperature zone), leached chernozem (temperate zone) and albic bleached soil (temperate zone) in China were determined with instrumental neutron activation analysis (INAA). Content and distribution patterns of ERRs are closely related to soil mechanical composition. In laterite, red earth, yellow brown soil and leached chernozem, REEs mainly enrich in fine grain particles or coarser grain partials while in clay particles no such enrichment was found. The distribution patterns of REEs in these soils are consistent with the REE features of their parent rocks. In all the six soils, REEs mainly exist in residual form, and with the increase of atomic number, intermediate REEs (IRRE) have lower proportions of residual form than light REEs (LREE) and heavy REEs (HREE). For the six unstable forms, water soluble form has the lowest proportion. The proportions of exchangeable form, carbonate and specific adsorption form are lower. The proportions of Fe-Min oxides form in different types of soils decrease gradually from Southern China to Northern China following the order: laterite > red earth > yellow brown soil > cinnamon soil, leached chernozem, albic bleached soil. Proportions of bound organic matters are higher and follow the order: Albic bleached soil > leached chernozem > red earth > laterite > yellow brown soil > cinnamon soil. The albic bleached soil has higher proportion of softly bound organic matter form. The leached chernozem has higher proportion of tightly bound organic matter form. Form of bound to organic matter in laterite is almost totally made up of form of softly bound to organic matter

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

    Science.gov (United States)

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

    2014-04-03

    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.

  15. Geophysical interpretation of U, Th, and rare earth element mineralization of the Bokan Mountain peralkaline granite complex, Prince of Wales Island, southeast Alaska

    Science.gov (United States)

    McCafferty, Anne E.; Stoeser, Douglas B.; Van Gosen, Bradley S.

    2014-01-01

    A prospectivity map for rare earth element (REE) mineralization at the Bokan Mountain peralkaline granite complex, Prince of Wales Island, southeastern Alaska, was calculated from high-resolution airborne gamma-ray data. The map displays areas with similar radioelement concentrations as those over the Dotson REE-vein-dike system, which is characterized by moderately high %K, eU, and eTh (%K, percent potassium; eU, equivalent parts per million uranium; and eTh, equivalent parts per million thorium). Gamma-ray concentrations of rocks that share a similar range as those over the Dotson zone are inferred to locate high concentrations of REE-bearing minerals. An approximately 1300-m-long prospective tract corresponds to shallowly exposed locations of the Dotson zone. Prospective areas of REE mineralization also occur in continuous swaths along the outer edge of the pluton, over known but undeveloped REE occurrences, and within discrete regions in the older Paleozoic country rocks. Detailed mineralogical examinations of samples from the Dotson zone provide a means to understand the possible causes of the airborne Th and U anomalies and their relation to REE minerals. Thorium is sited primarily in thorite. Uranium also occurs in thorite and in a complex suite of ±Ti±Nb±Y oxide minerals, which include fergusonite, polycrase, and aeschynite. These oxides, along with Y-silicates, are the chief heavy REE (HREE)-bearing minerals. Hence, the eU anomalies, in particular, may indicate other occurrences of similar HREE-enrichment. Uranium and Th chemistry along the Dotson zone showed elevated U and total REEs east of the Camp Creek fault, which suggested the potential for increased HREEs based on their association with U-oxide minerals. A uranium prospectivity map, based on signatures present over the Ross-Adams mine area, was characterized by extremely high radioelement values. Known uranium deposits were identified in the U-prospectivity map, but the largest tract occurs

  16. Thorium determination by X-ray Fluorescence Spectrometry in simulated thorex process solutions

    International Nuclear Information System (INIS)

    Yamaura, M.; Matsuda, H.T.

    1989-01-01

    The X-ray fluorescence method for thorium determination in aqueous and organic (TBP-n-dodecane) solutions is described. The thin film-technique for sample preparation and a suitable internal standard have been used. Some parameters as analytical line, internal standard, filter paper, paper geometry, sample volume and measurement conditions were studied. Uranium, fission products, corrosion products and thorex reagent components were studied as interfering elements in the thorium analysis, as well as the matrix effect by using the thorex process simulated solutions the method to thorium determination in irradiated thorium solutions was applied. (M.J.C.) [pt

  17. Rare earths and energy critical elements: a roadmap and strategy for India

    International Nuclear Information System (INIS)

    Bharadwaj, Mridula Dixit; Balasubramanian, N.

    2014-01-01

    The aim of this presentation is to summarise and update the report 'Rare Earths (RE) and Energy Critical Elements (ECE): A Roadmap and Strategy for India' released in July 2012. The background to the report is as follows. The Ministry of Mines (MoM), Government of India constituted a steering committee in August 2011 to develop a strategy paper on status and availability of Rare Earth Elements (REE) and Energy Critical Elements (ECE). The race to find alternatives to RE by the use of supercomputers and genetic algorithms will be described. Many of the ECE eg. gallium, germanium, indium, selenium and tellurium are by-products of main metals: aluminium, copper, zinc and tin. Their production is restricted by that of main metals. Saline brine and subsoil bitterns are sources of lithium. Uranium, and niobium alloying with zirconium are critical to nuclear energy. Exploration, applications, recycling and recovery of these elements will be discussed. Our report and presentation lay stress on novel routes that emphasise self-reliance and not merely economic viability and also provide short, medium and long term options along with proposals for specific policy and legislative interventions

  18. Determination of rare earth elements in red mud by ICP-MS

    International Nuclear Information System (INIS)

    Kumar, Sanjukta A.; Suvarna, S.; Kiran Kumar, G.

    2017-01-01

    Red mud or red sludge is a highly alkaline waste product composed mainly of iron oxide that is generated in the industrial production of aluminum from bauxite. With about 77 million tons of this hazardous material being produced annually, red mud poses a serious disposal problem in the mining industry. Discharge of red mud is hazardous environmentally because of its alkalinity. Many studies have been conducted to develop uses of red mud. An estimated 2 to 3 million tones are used annually in the production of cement, road construction and as a source for iron. Potential applications include the production of low cost concrete, application to sandy soils to improve phosphorus cycling, amelioration of soil acidity, landfill capping and carbon sequestration. Red mud contains a large amount of iron along with appreciable concentrations of many strategic elements such as rare earth elements and therefore can be a source of valuable secondary raw material. This necessitates the elemental characterization of red mud. This paper presents an effective dissolution procedure using a mixture of phosphoric acid and nitric acid for red mud followed by determination of rare earth elements by ICP-MS. The method was validated by spike recovery experiments. The recoveries were found within 98 to 102 %. The relative standard deviation (RSD) of the method was found to be within 5 %

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

    Science.gov (United States)

    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.

  20. Bioleaching of rare earth and radioactive elements from red mud using Penicillium tricolor RM-10.

    Science.gov (United States)

    Qu, Yang; Lian, Bin

    2013-05-01

    The aim of this work is to investigate biological leaching of rare earth elements (REEs) and radioactive elements from red mud, and to evaluate the radioactivity of the bioleached red mud used for construction materials. A filamentous, acid-producing fungi named RM-10, identified as Penicillium tricolor, is isolated from red mud. In our bioleaching experiments by using RM-10, a total concentration of 2% (w/v) red mud under one-step bioleaching process was generally found to give the maximum leaching ratios of the REEs and radioactive elements. However, the highest extraction yields are achieved under two-step bioleaching process at 10% (w/v) pulp density. At pulp densities of 2% and 5% (w/v), red mud processed under both one- and two-step bioleaching can meet the radioactivity regulations in China. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. A preliminary research on characteristics of rare-earth elements in ancient pottery of neolithic age in Su Wan area

    International Nuclear Information System (INIS)

    Chen Shuyu; Lin Shuqin; Peng Zicheng; Liu Fangxin; Zhang Jingguo

    1995-01-01

    The content of rare-earth elements in the three ancient ruins of pottery of the Neolithic age along Yangtze River is analyzed by means of Inductively Coupled Plasma Atomic Emission Spectrometry and X-ray fluorescence Spectrometry. It is shown that the distribution of rare-earth elements varies with the sites where the ancient pottery samples were unearthed. Therefore the analysis of the content of the rate-earth elements may help explore the ancient pottery production sites and the route of the ancient culture exchange

  2. Dispersion and concentration of elements in the Earth's crust an overview

    International Nuclear Information System (INIS)

    Iiyama, J.T.

    1991-01-01

    During the Earth's history of 4,500 x 10 6 years, the distribution of elements in its crust is strongly modified from the initial pattern. The paper overlooks at first how and to what extent this modification could be take place. It is emphasized that water in deep as well as in shallow parts of the crust plays an essential role in the transportation of elements. Whether a particular element thus transported by water are concentrated in particular places or diluted and dispersed in the crust or brought to the surface and join into the surface water depends on the geological and geochemical condition of the passages of these waters acting as transporter of the elements. If there was no preferential passages for water, these elements and water will diffuse into the surroundings and no particular concentration of elements will be resulted. On the contrary, the presence of preferential conduit (such as fissure or faults) will offer the places adequate for this concentration provided that a favorable physical and chemical conditions are present. The review thus intends to point out the importance of the tectono-geochemical conditions to be taken into consideration for the planning of the nuclear wastes disposal and of the environmental protection. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    El-Taher, A. [Physics Department, Faculty of Science, Al-Azher University, Assuit Branch (Egypt)]. E-mail: Atef_Eltaher@hotmail.com

    2007-04-15

    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 7x10{sup 11} n/cm{sup 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.

  4. Uranium and Thorium precipitation from solution of slag II

    International Nuclear Information System (INIS)

    Mutia Anggraini; Budi Sarono; Sugeng Waluyo; Rusydi; Sujono

    2015-01-01

    Tin smelting process produces waste in the form of large amount of slag II. Slag II still consist of major elements such as 0.0619% uranium, 0.530% thorium, 0.179% P 2 O 5 and 6.194% RE total oxide. Based on that fact, the processing of slag II is interesting to be researched, particularly in separating uranium and thorium which contained in slag II. Uranium and thorium dissolved using acid reagent (H 2 SO 4 ). Percentage recovery of uranium, thorium, phosphate and RE oxides by dissolution method are 98.52%, 83.16%, 97.22%, and 69.62% respectively. Dissolved uranium, thorium, phosphate, and RE were each precipitated. The factors which considerable affect the precipitation process are reagent, pH, temperature, and time. NH 4 OH is used as precipitation reagent, optimum condition are pH 4. Temperature and time reaction did not influence this reaction. Percentage recovery of this precipitation process at optimum condition are 93.84% uranium and 84.33% thorium. (author)

  5. Resources and processing of thorium raw material

    International Nuclear Information System (INIS)

    Smirnov, Yu.V.; Efimova, Z.I.

    1981-01-01

    Results of the estimation of thorium raw material resources, methods of thorium raw material processing as well as possibilities for thorium production and its compounds of nuclear purity making in a number of countries are considered. It is shown that thorium global resources available are sufficient to be a base for uranium-thorium fuel cycle. Technological processes of thorium raw material processing and production of thorium compounds-oxide and metal out of different forms of thorium raw material have been developed, all flowsheets permit the complex use of thorium raw material and decrease thorium production costs. Prospects for thorium use as a fuel in heavy-water and high-temperature reactors are noted [ru

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

    Science.gov (United States)

    Wang, Lingqing; Liang, Tao

    2015-07-22

    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.

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Madhavi Z [ORNL; Fox, Dr. Richard V [Idaho National Laboratory (INL); Miziolek, Andrzej W [United States Army Research Laboratory; DeLucia, Frank C [United States Army Research Laboratory; Andre, Nicolas O [ORNL

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Madhavi Z [ORNL; Fox, Dr. Richard V [Idaho National Laboratory (INL); Miziolek, Andrzej W [United States Army Research Laboratory; DeLucia, Frank C [United States Army Research Laboratory; Andre, Nicolas O [ORNL

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. A Novel Approach for Earthing System Design Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Sajad Samadinasab

    2017-04-01

    Full Text Available Protection of equipment, safety of persons and continuity of power supply are the main objectives of the grounding system. For its accurate design, it is essential to determine the potential distribution on the earth surface and the equivalent resistance of the system. The knowledge of such parameters allows checking the security offered by the grounding system when there is a failure in the power systems. A new method to design an earthing systems using Finite Element Method (FEM is presented in this article. In this approach, the influence of the moisture and temperature on the behavior of soil resistivity are considered in EARTHING system DESIGN. The earthing system is considered to be a rod electrode and a plate type electrode buried vertically in the ground. The resistance of the system which is a very important factor in the design process is calculated using FEM. FEM is used to estimate the solution of the partial differential equation that governs the system behavior. COMSOL Multiphysics 4.4 which is one of the packages that work with the FEM is used as a tool in this design. Finally the values of the resistance obtained by COMSOL Multiphysics are compared with the proven analytical formula values for the ground resistance, in order to prove the work done with COMSOL Multiphysics.

  13. A novel approach for acid mine drainage pollution biomonitoring using rare earth elements bioaccumulated in the freshwater clam Corbicula fluminea.

    Science.gov (United States)

    Bonnail, Estefanía; Pérez-López, Rafael; Sarmiento, Aguasanta M; Nieto, José Miguel; DelValls, T Ángel

    2017-09-15

    Lanthanide series have been used as a record of the water-rock interaction and work as a tool for identifying impacts of acid mine drainage (lixiviate residue derived from sulphide oxidation). The application of North-American Shale Composite-normalized rare earth elements patterns to these minority elements allows determining the origin of the contamination. In the current study, geochemical patterns were applied to rare earth elements bioaccumulated in the soft tissue of the freshwater clam Corbicula fluminea after exposure to different acid mine drainage contaminated environments. Results show significant bioaccumulation of rare earth elements in soft tissue of the clam after 14 days of exposure to acid mine drainage contaminated sediment (ΣREE=1.3-8μg/gdw). Furthermore, it was possible to biomonitor different degrees of contamination based on rare earth elements in tissue. The pattern of this type of contamination describes a particular curve characterized by an enrichment in the middle rare earth elements; a homologous pattern (E MREE =0.90) has also been observed when applied NASC normalization in clam tissues. Results of lanthanides found in clams were contrasted with the paucity of toxicity studies, determining risk caused by light rare earth elements in the Odiel River close to the Estuary. The current study purposes the use of clam as an innovative "bio-tool" for the biogeochemical monitoring of pollution inputs that determines the acid mine drainage networks affection. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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

  15. Thorium utilisation in thermal reactors

    International Nuclear Information System (INIS)

    Balakrishnan, K.

    1997-01-01

    It is now more or less accepted that the best way to use thorium is in thermal reactors. This is due to the fact that U233 is a good material in the thermal spectrum. Studies of different thorium cycles in various reactor concepts had been carried out in the early days of nuclear power. After three decades of neglect, the world is once again looking at thorium with some interest. We in India have been studying thorium cycles in most of the existing thermal reactor concepts, with greater emphasis on heavy water reactors. In this paper, we report some of the work done in India on different thorium cycles in the Indian pressurized heavy water reactor (PHWR), and also give a description of the design of the advanced heavy water reactor (AHWR). (author). 1 ref., 2 tabs., 5 figs

  16. A first report of rare earth elements in northwestern Mediterranean seaweeds.

    Science.gov (United States)

    Squadrone, Stefania; Brizio, Paola; Battuello, Marco; Nurra, Nicola; Sartor, Rocco Mussat; Benedetto, Alessandro; Pessani, Daniela; Abete, Maria Cesarina

    2017-09-15

    The concentrations of rare earth elements (REE) were determined by ICP-MS in dominant seaweed species, collected from three locations of the northwestern Mediterranean Sea. This is the first study to define levels and patterns of REE in macro algae from these coastal areas. Rare elements are becoming emerging inorganic contaminants in marine ecosystems, due to their worldwide increasing applications in industry, technology, medicine and agriculture. Significant inter-site and interspecies differences were registered, with higher levels of REE in brown and green macro algae than in red seaweeds. Levels of light REE were also observed to be greater compared to heavy REE in all samples. One of the investigated locations (Bergeggi, SV) had higher REE and ΣREE concentrations, probably due to its proximity to an important commercial and touristic harbor, while the other two sites were less affected by anthropogenic contaminations, and showed comparable REE patterns and lower concentrations. Rare earth elements in seaweeds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Online preconcentration ICP-MS analysis of rare earth elements in seawater

    Science.gov (United States)

    Hathorne, Ed C.; Haley, Brian; Stichel, Torben; Grasse, Patricia; Zieringer, Moritz; Frank, Martin

    2012-01-01

    The rare earth elements (REEs) with their systematically varying properties are powerful tracers of continental inputs, particle scavenging intensity and the oxidation state of seawater. However, their generally low (˜pmol/kg) concentrations in seawater and fractionation potential during chemical treatment makes them difficult to measure. Here we report a technique using an automated preconcentration system, which efficiently separates seawater matrix elements and elutes the preconcentrated sample directly into the spray chamber of an ICP-MS instrument. The commercially available "seaFAST" system (Elemental Scientific Inc.) makes use of a resin with ethylenediaminetriacetic acid and iminodiacetic acid functional groups to preconcentrate REEs and other metals while anions and alkali and alkaline earth cations are washed out. Repeated measurements of seawater from 2000 m water depth in the Southern Ocean allows the external precision (2σ) of the technique to be estimated at mine water reference materials diluted with a NaCl matrix with recommended values in the literature. This makes the online preconcentration ICP-MS technique advantageous for the minimal sample preparation required and the relatively small sample volume consumed (7 mL) thus enabling large data sets for the REEs in seawater to be rapidly acquired.

  18. Physico-chemical characteristics of sulfated mixed oxides of Sn with some rare earth elements

    International Nuclear Information System (INIS)

    Jyothi, T.M.; Mirakar, S.P.; Sreekumar, K.; Sugunan, S.; Talawar, M.B.

    2000-01-01

    A series of binary mixed oxides of tin with three rare earth elements viz. La, Ce and Sm were prepared by coprecipitation method and sulfate treatment was performed by treating the mixed hydroxides with sulfuric acid or ammonium sulfate. The physico-chemical characterization has been done by XRD, BET-SA, SEM, EDX, TG-DTA and IR spectroscopy. Adsorption of n-butylamine was used to probe the acidic properties of the catalysts. The strength and distribution of acid sites depend on the mixed metal oxide composition, as well as on the preparation method. The rare earth modified sulfated tin oxide catalysis are more active in the oxidative dehydrogenation of cyclohexanol and cyclohexane, compared to the corresponding mixed oxide systems and sulfated tin oxide. Among the different sulfated oxide systems investigated, cerium promoted catalysts displayed a better selectivity towards dehydrogenation products. (author)

  19. Determination of rare-earth elements content in granitic rocks by argon plasma emission spectrometry

    International Nuclear Information System (INIS)

    Merodio, J.C.; Martinez, J.M.

    1990-01-01

    A method has been developed that enables the rare-earth elements in granitic rocks to be measured sequentially, using an inductively coupled plasma (ICP) source spectrometer with medium spectral resolution (0,02nm). The rocks were dissolved in an open system with a mixture of nitric-hydrofluoric-perchloric acids. Any residues remaining at this stage were removed by filtration and digested using a mini-fusion method with lithium tetraborate. Prior to the excitation in the spectrometer the rare-earth group was separated from other constituents using cation-exchange chromatography. A detailed study of spectral interferences and the evaluation of the detection limits have been performed. Five geochemical reference sample (granitic rocks) were analyzed and the obtained results agree favourably with recommended values and with reported determinations, using high spectral resolution ICP spectrometry. (Author) [es

  20. ICP Mass and Optical Emission Spectrometry of Ore Samples Containing Rare Earth Elements

    International Nuclear Information System (INIS)

    Mohammed, A.E.W.M.

    2013-01-01

    Inductively Coupled Plasma Optical Emission and Mass Spectrometry (ICP-OES and ICPMS) are widely accepted as a rapid and sensitive techniques for Rare Earth Elements (REEs) analysis of geological samples. However, the achievable accuracy of these techniques are seriously limited by the problem of matrix interferences. In this study, matrix effects in ICP-AES were addressed using two approaches. In the first approach, the mechanisms of matrix interferences and analyte excitation were elucidated fundamentally. First, matrix effects from a comprehensive list of thirty-nine elements were investigated. It was confirmed that matrix elements with low second (instead of the widely reported first) ionization potentials (IP) produce a stronger matrix effect in all cases. Another critical parameter defining the severity of the matrix effect was found to be the availability of low-lying energy levels in the doubly charged matrix ion. Penning ionization followed by ion electron recombination through successive cycles is proposed as the mechanism for the more severe matrix effects caused by low second-IP matrices. In the second approach ICP-OES and ICP-MS are applied in this study for the analysis of Rare Earth Elements of two selected standard reference samples namely AGV-2 and BCR-2 beside a fluorspar geological sample (G-9 sample). Effective procedures are developed to avoid the spectral interference from matrix elements by using ion exchange resin Amberlite IR-120 before determination of REEs using ICP-OES and ICPMS. The potential of the method is evaluated by analysis of Certified Reference Materials (AGV-2 and BCR-2). Results obtained by ICP-MS show that experimental data are in agreement with the certified values and their values could be used as a quantitative data. The results obtained using ICP-OES were compared and discussed.

  1. The effect of acid rain stress on membrane protective system of spinach and the conservation of rare earth elements

    International Nuclear Information System (INIS)

    Chongling, Y; Yetang, H.

    1998-01-01

    Full text: Based on pot experiments, the effect of acid rain stress on membrane protective system of spinach and the effect of rare earth elements has been studied. The results showed, stress of acid rain resulted in decrease of over all level of superoxide dismutase activity, catalase activity and increase of peroxidase (POD) activity. After being treated by rare earth elements, the overall level of superoxide dismutase activity and catalase activity were increased and the peak value of activity variation curve moved toward to the direction of higher acidity. POD activity increased slightly, comparing with the plants that hadn't been treated by rare earth elements under same acid rain condition; the three important enzymes of membrane protective system could be kept on a relatively stable level. It was clear that in relative lower acidity condition, rare earth elements can reduce the impact of acid rain on the membrane protective system

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  4. Rare earth element distributions in the West Pacific: Trace element sources and conservative vs. non-conservative behavior

    Science.gov (United States)

    Behrens, Melanie K.; Pahnke, Katharina; Paffrath, Ronja; Schnetger, Bernhard; Brumsack, Hans-Jürgen

    2018-03-01

    Recent studies suggest that transport and water mass mixing may play a dominant role in controlling the distribution of dissolved rare earth element concentrations ([REE]) at least in parts of the North and South Atlantic and the Pacific Southern Ocean. Here we report vertically and spatially high-resolution profiles of dissolved REE concentrations ([REE]) along a NW-SE transect in the West Pacific and examine the processes affecting the [REE] distributions in this area. Surface water REE patterns reveal sources of trace element (TE) input near South Korea and in the tropical equatorial West Pacific. Positive europium anomalies and middle REE enrichments in surface and subsurface waters are indicative of TE input from volcanic islands and fingerprint in detail small-scale equatorial zonal eastward transport of TEs to the iron-limited tropical East Pacific. The low [REE] of North and South Pacific Tropical Waters and Antarctic Intermediate Water are a long-range (i.e., preformed) laterally advected signal, whereas increasing [REE] with depth within North Pacific Intermediate Water result from release from particles. Optimum multiparameter analysis of deep to bottom waters indicates a dominant control of lateral transport and mixing on [REE] at the depth of Lower Circumpolar Deep Water (≥3000 m water depth; ∼75-100% explained by water mass mixing), allowing the northward tracing of LCDW to ∼28°N in the Northwest Pacific. In contrast, scavenging in the hydrothermal plumes of the Lau Basin and Tonga-Fiji area at 1500-2000 m water depth leads to [REE] deficits (∼40-60% removal) and marked REE fractionation in the tropical West Pacific. Overall, our data provide evidence for active trace element input both near South Korea and Papua New Guinea, and for a strong lateral transport component in the distribution of dissolved REEs in large parts of the West Pacific.

  5. The Distribution of Heat-Producing Radioactive Elements in the Deep Earth

    Science.gov (United States)

    Chidester, Bethany A.

    The Earth is a heat engine, where large differences in temperature between the interior and the surface drive large-scale movement that manifests as plate tectonics and the geomagnetic field that protects us from the Sun's harmful charged particles. Decay of the long-lived radioactive elements U, Th, and K is expected to contribute as much as 45% of the current heat production in the Earth, and that heat production was five times higher early in Earth's history. It is unclear how this heat source affects the thermal and dynamic evolution of the Earth's core and mantle and how that contribution has changed over geologic time. This dissertation addresses this problem in several different ways. This work represents the first high-pressure, high-temperature metal-silicate partitioning experiments for U, Th, and K in the laser-heated diamond anvil cell at conditions relevant to core formation. A chemical model is developed using parameterization of these partitioning data to constrain the concentrations of each of these elements in the core. Using a numerical calculation, it is then determined how that radioactive heat would contribute to the core's energy and entropy budget through time. One finds that, despite its strong lithophile nature at the surface, U partitions significantly into the metallic phase at increasing temperatures. This may be due to a decrease in U valence from 4+ to 2+ in high-pressure silicate melts, which our data supports. However, K and Th do not exhibit a similar change in behavior at these conditions, and this may drive fractionation between U and Th in the deep mantle. At the most extreme conditions of core formation, enough U could exist in the core to produce up to 4.4 TW of heat 4.5 billion years ago. Potassium could produce much less heat than U early on (fluorite- type structure (thorianite) that is stable at ambient conditions to the previously identified cotunnite-type structure around 19 GPa and 1500 K. It remains in the cotunnite

  6. Uncertainty propagation through correction methodology for the determination of rare earth elements by quadrupole based inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Raut, Narendra M.; Huang, L.-S.; Lin, K.-C.; Aggarwal, Suresh K.

    2005-01-01

    Determination of rare earth elements by quadrupole based inductively coupled plasma mass spectrometry (ICP-QMS) shows several spectroscopic overlaps from M + , MO + and MOH + ions. Especially, the spectroscopic interferences are observed from the atomic and molecular species of lighter rare earth elements including Ba during the determination of Eu, Gd and Tb. Mathematical correction methods, knowing the at.% abundances of different interfering isotopes, and the extent of formation of molecular species determined experimentally, have been used to account for various spectroscopic interferences. However, the uncertainty propagated through the mathematical correction limits its applicability. The uncertainty propagation increases with the increase in contribution from interfering species. However, for the same extent of total contribution, the overall error decreases when the interfering species are more than one. In this work, chondrite as well as a few geological reference materials containing different proportions of various rare earth elements have been used to study the contributions of different interfering species and the corresponding uncertainty in determining the concentrations of rare earth elements. A number of high abundant isotopes are proposed for determining the concentrations of various rare earth elements. The proposed isotopes are tested experimentally for determining the concentrations of different rare earth elements in two USGS reference materials AGV-1 and G-2. The interferences over those isotopes are corrected mathematically and the uncertainties propagated due to correction methodology are determined for those isotopes. The uncertainties in the determined concentrations of rare earth elements due to interference correction using the proposed isotopes are found to be comparable with those obtained by the commonly used isotopes for various rare earth elements

  7. Selective liquid chromatographic separation of yttrium from heavier rare earth elements using acetic acid as a novel eluent.

    Science.gov (United States)

    Kifle, Dejene; Wibetoe, Grethe

    2013-09-13

    One of the major difficulties in the rare earth elements separation is purification of yttrium from heavy rare earth elements. Thus, an HPLC method using acetic acid as novel eluent was explored for selective separation of yttrium form the heavy rare earth elements. When acetic acid is used as a mobile phase yttrium eluted with the lighter lanthanides. This is contrary to its relative position amongst heavier lanthanides when eluents commonly used for separation of rare earth elements were employed. The shift in elution position of yttrium with acetic acid as eluent may reflect a relatively lower stability constant of the yttrium-AcOH complex (in the same order as for the lighter lanthanides) compared to the corresponding AcOH complexes with heavy lanthanides, enabling selective separation of yttrium from the latter. The method was successfully used for selective separation of yttrium in mixed rare earth sample containing about 80% of yttrium and about 20% of heavy rare earth oxides. Thus, the use of AcOH as eluent is an effective approach for separating and determining the trace amounts of heavy rare earth elements in large amounts of yttrium matrix. Separation was performed on C18 column by running appropriate elution programs. The effluent from the column was monitored with diode array detector at absorbance wavelength of 658nm after post column derivatization with Arsenazo III. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. New neutron-deficient isotopes of barium and rare-earth elements

    CERN Document Server

    Bogdanov, D D; Karnaukhov, V A; Petrov, L A; Plochocki, A; Subbotin, V G; Voboril, J

    1976-01-01

    The authors present an investigation of the short-lived neutron- deficient isotopes of barium and rare-earth elements. By using the BEMS-2 isotope separator on a heavy ion beam, 19 new isotopes were produced with mass numbers ranging from 117 to 138. Five of these (/sup 117/Ba, /sup 129,131/Nd and /sup 133,135/Sm) turned out to be delayed proton emitters. The beta -decay probabilities for the new isotopes have been analyzed in terms of the beta -strength function. An analysis of the proton spectrum shape has been performed using the statistical model for delayed proton emission.

  10. Rare earths elements in the rocks of the Cinovec granite cupola (Czechoslovakia)

    International Nuclear Information System (INIS)

    Stemprok, M.

    1989-01-01

    Rare earth elements (REE) were analyzed by the nondestructive INAA method in samples from drilling CS-1 situated in the center of the Cinovec granite cupola, eastern Krusne hory Mts., Czechoslovakia. The 1596 m deep drilling found upper zinnwaldite and lower protolithionite granites which differ in their amounts of REE. Both types of granites that belong to the granites of the Younger Intrusive Complex of the Krusne Hory Mts. give flat chondrite-normalized patterns characterized by a large negative Eu anomaly. (author). 9 figs., 5 tabs., 25 refs

  11. Determination of rare earth elements in rocks by neutron activation analysis with pre-irradiation separation

    International Nuclear Information System (INIS)

    Alcala, A.L.

    1991-01-01

    Rare earth elements were determined by neutron activation analysis in rocks, a group separation before irradiation was developed. The international reference standards AGV-1, BE-N and JB-1, as well the Brazilian geological standards BB-1 and GB-1, provided by the Instituto de Geociencias da Universidade Federal da Bahia, were analysed. The method was based on acid digestion of the samples, cation exchange separation, and coprecipitation of the REE with calcium oxalate. Interferents like U, Th, Ta and Fe were eliminated. The concentration values of eleven REE's (La, Co, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Yb and Lu) were determined. (author)

  12. Determination of Rare Earth Elements in Geological Samples Using Laser-Induced Breakdown Spectroscopy (LIBS).

    Science.gov (United States)

    Bhatt, Chet R; Jain, Jinesh C; Goueguel, Christian L; McIntyre, Dustin L; Singh, Jagdish P

    2018-01-01

    Laser-induced breakdown spectroscopy (LIBS) was used to detect rare earth elements (REEs) in natural geological samples. Low and high intensity emission lines of Ce, La, Nd, Y, Pr, Sm, Eu, Gd, and Dy were identified in the spectra recorded from the samples to claim the presence of these REEs. Multivariate analysis was executed by developing partial least squares regression (PLS-R) models for the quantification of Ce, La, and Nd. Analysis of unknown samples indicated that the prediction results of these samples were found comparable to those obtained by inductively coupled plasma mass spectrometry analysis. Data support that LIBS has potential to quantify REEs in geological minerals/ores.

  13. Electrodeposition Techniques for the Preparation of Beta-Sprectroscopy Sources of Rare-Earth Elements

    DEFF Research Database (Denmark)

    Hansen, P. Gregers; Høgh, J.; Nielsen, H. L.

    1964-01-01

    Thin, uniform radioactive deposits of rare earths and related elements can be prepared by cathodic electrodeposition of their hydroxides. The main theoretical and experimental features of this process are reviewed and plating cell design and the choice of conditions are described together...... with the associated radio-chemical methods. The use of copper-backed nickel films is shown to allow the preparation of beta sources on quite thin (down to 45 μg cm−2) backings, if the copper layer is etched selectively after the radioactivity has been plated onto the nickel....

  14. Effect of Rare Earth Element on Microstructure and Properties of in situ Synthesized TiB2/Al Composites

    Directory of Open Access Journals (Sweden)

    QU Min

    2018-03-01

    Full Text Available The effect of rare earth element Ce, Sc and Er on TiB2 particles and matrix alloy micros-tructure of TiB2/Al composites was studied with in situ synthesis method. It shows that the addition of rare earth element improves the microstructure and properties of TiB2/Al composites notably. The particles of TiB2 are relatively homogenously distributed as adding 0.3% (mass fraction rare earth element Sc and Er, moreover, it is Er that refines the microstructure of matrix alloy most significantly, then is Sc. Similarly, it is demonstrated that the addition of Sc and Er results in better tensile strength, which is enhanced by 32% and 31%, respectively; the addition of Er also leads to the best ductility by 85% with optimal tensile property. Meanwhile, fracture morphology analysis reveals that the fracture of the composites is microporous gathered ductile fracture when adding Sc and Er. Finally, it is verified that the mechanism of rare earth element on composites lies in two aspects:one is that the addition of rare earth element improves the wettability of the composites and suppresses the agglomeration of TiB2 particles; the other is that the addition of rare earth element refines the microstructure of matrix alloy and then improves the tensile strength of the composites.

  15. Leaching of Light Rare Earth Elements from Sichuan Bastnaesite: A Facile Process to Leach Trivalent Rare Earth Elements Selectively from Tetravalent Cerium

    Science.gov (United States)

    Shen, Yueyue; Jiang, Ying; Qiu, Xianying; Zhao, Shilin

    2017-10-01

    The effects of the nitric acid concentration, leaching time, leaching temperature, and solid-to-liquid ratio on leaching efficiency were examined. From those results, a facile process for the selective leaching of trivalent rare earth elements (RE(III)) from tetravalent cerium (Ce(IV)) was proposed. The roasted bastnaesite was used to leach 34.87% of RE(III) and 2.15% of Ce(IV) at 60°C for 0.5 h with an acid concentration of 0.5 mol/L. This selective leaching process can be described by the shrinking-core model that follows the kinetic model 1 - 2/3 α - (1 - α)2/3. Subsequently, the leached slag was hydrothermally treated and followed by thorough leaching with 4.0-mol/L nitric acid. Furthermore, the specific surface area of the final leached slag is 57.7 m2/g, which is approximately 650 times higher than that of raw ore. Finally, selective leaching of RE(III) (>90%) was achieved without using an organic solvent for extraction, whereas lower value Ce(IV)was presented in the leached slag (>92%).

  16. Geochemical characteristics of rare earth elements in different types of soil: A chemometric approach.

    Science.gov (United States)

    Khan, Aysha Masood; Behkami, Shima; Yusoff, Ismail; Md Zain, Sharifuddin Bin; Bakar, Nor Kartini Abu; Bakar, Ahmad Farid Abu; Alias, Yatimah

    2017-10-01

    Rare earth elements (REEs) are becoming significant due to their huge applications in many industries, large-scale mining and refining activities. Increasing usage of such metals pose negative environmental impacts. In this research ICP-MS has been used to analyze soil samples collected from former ex-mining areas in the depths of 0-20 cm, 21-40 cm, and 41-60 cm of residential, mining, natural, and industrial areas of Perak. Principal component analysis (PCA) revealed that soil samples taken from different mining, industrial, residential, and natural areas are separated into four clusters. It was observed that REEs were abundant in most of the samples from mining areas. Concentration of the rare elements decrease in general as we move from surface soil to deeper soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. A new instrumental method for the analysis of rare earth elements

    International Nuclear Information System (INIS)

    Santos, A.N. dos.

    1975-01-01

    A method for the simultaneous elemental analysis of the rare earths is proposed and empirically verified. It is based on the analysis of the escape peaks, generated by the characteristic X-rays of these elements in a xenon proportional counter. The peaks are well resolved and intense, in contrast to the photopeak which is lost in the background. The spectra are generated by a radioisotope such as Co 57 , and the equipment is simple, portable and low cost, although resolution challenges that of the best solid state detectors. Since X-rays are utilized, matrix, granulometric or mineralogical effects are minimal, and the method is rapid, sensitive, non-destructive and requires little or no sample preparation. The results are preliminary and an improvement in resolution of up to fourfold seems possible; precision is better than 0,1% in concentrated samples and sensitivity is about 20 μg

  18. Effects of rare earth elements and REE-binding proteins on physiological responses in plants.

    Science.gov (United States)

    Liu, Dongwu; Wang, Xue; Chen, Zhiwei

    2012-02-01

    Rare earth elements (REEs), which include 17 elements in the periodic table, share chemical properties related to a similar external electronic configuration. REEs enriched fertilizers have been used in China since the 1980s. REEs could enter the cell and cell organelles, influence plant growth, and mainly be bound with the biological macromolecules. REE-binding proteins have been found in some plants. In addition, the chlorophyll activities and photosynthetic rate can be regulated by REEs. REEs could promote the protective function of cell membrane and enhance the plant resistance capability to stress produced by environmental factors, and affect the plant physiological mechanism by regulating the Ca²⁺ level in the plant cells. The focus of present review is to describe how REEs and REE-binding proteins participate in the physiological responses in plants.

  19. Rationally designed mineralization for selective recovery of the rare earth elements

    Science.gov (United States)

    Hatanaka, Takaaki; Matsugami, Akimasa; Nonaka, Takamasa; Takagi, Hideki; Hayashi, Fumiaki; Tani, Takao; Ishida, Nobuhiro

    2017-05-01

    The increasing demand for rare earth (RE) elements in advanced materials for permanent magnets, rechargeable batteries, catalysts and lamp phosphors necessitates environmentally friendly approaches for their recovery and separation. Here, we propose a mineralization concept for direct extraction of RE ions with Lamp (lanthanide ion mineralization peptide). In aqueous solution containing various metal ions, Lamp promotes the generation of RE hydroxide species with which it binds to form hydrophobic complexes that accumulate spontaneously as insoluble precipitates, even under physiological conditions (pH ~6.0). This concept for stabilization of an insoluble lanthanide hydroxide complex with an artificial peptide also works in combination with stable scaffolds like synthetic macromolecules and proteins. Our strategy opens the possibility for selective separation of target metal elements from seawater and industrial wastewater under mild conditions without additional energy input.

  20. Revisiting the plant hyperaccumulation criteria to rare plants and earth abundant elements

    Energy Technology Data Exchange (ETDEWEB)

    Branquinho, Cristina [Universidade de Lisboa, Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Campo Grande C2, Piso 4, 1749-016 Lisbon (Portugal) and Universidade Atlantica, Antiga Fabrica da Polvora de Barcarena, 2745-615 Barcarena (Portugal)]. E-mail: cmbranquinho@fc.ul.pt; Serrano, Helena Cristina [Universidade de Lisboa, Museu Nacional de Historia Natural, Jardim Botanico (Portugal); Pinto, Manuel Joao [Universidade de Lisboa, Museu Nacional de Historia Natural, Jardim Botanico (Portugal); Martins-Loucao, Maria Amelia [Universidade de Lisboa, Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Campo Grande C2, Piso 4, 1749-016 Lisbon (Portugal); Universidade de Lisboa, Museu Nacional de Historia Natural, Jardim Botanico (Portugal)

    2007-03-15

    The several established criteria to define a hyperaccumulator plant were applied to a rare and endangered species, Plantago almogravensis, and to the 3rd most abundant element in the earth crust, Al. Using the most common criteria, P. almogravensis undoubtedly is an Al hyperaccumulator plant. If the recent proposed requirements were considered, most of them matching those for a plant to be used in phytoextraction, it can only be considered an unusual accumulator of Al. A discussion is made concerning the several criteria of a hyperaccumulator plant in order to include rare and endemic ones and abundant elements. In ecological terms, the enrichment in Al and Fe observed may account for the differences in the vegetation pattern. Due to the rarity and endangered nature of this plant, the contribution of this work is also relevant for the ecological understanding and the development of conservation options of this endemic species. - Revisiting plant hyperaccumulation criteria.

  1. Revisiting the plant hyperaccumulation criteria to rare plants and earth abundant elements

    International Nuclear Information System (INIS)

    Branquinho, Cristina; Serrano, Helena Cristina; Pinto, Manuel Joao; Martins-Loucao, Maria Amelia

    2007-01-01

    The several established criteria to define a hyperaccumulator plant were applied to a rare and endangered species, Plantago almogravensis, and to the 3rd most abundant element in the earth crust, Al. Using the most common criteria, P. almogravensis undoubtedly is an Al hyperaccumulator plant. If the recent proposed requirements were considered, most of them matching those for a plant to be used in phytoextraction, it can only be considered an unusual accumulator of Al. A discussion is made concerning the several criteria of a hyperaccumulator plant in order to include rare and endemic ones and abundant elements. In ecological terms, the enrichment in Al and Fe observed may account for the differences in the vegetation pattern. Due to the rarity and endangered nature of this plant, the contribution of this work is also relevant for the ecological understanding and the development of conservation options of this endemic species. - Revisiting plant hyperaccumulation criteria

  2. Rare earth elements determination in medicinal plants by Neutron Activation Analisys

    International Nuclear Information System (INIS)

    Goncalves, Rodolfo D.M.R.; Francisconi, Lucilaine S.; Silva, Paulo S.C. da

    2013-01-01

    Rare Earth Elements (REEs) have been considered nontoxic for human health and for the environment; however, the use of REEs in the development of recent technologies has increased the interest un their biological effects. Some studies related to their concentration in foodstuffs were published but REEs levels in medicinal plants are still unknown. The objective of this study was to determine the Rees concentration in the set of 59 medicinal herbs commonly used by Brazilian folk. Results showed that plants can concentrate REEs in their aerial parts, but the amount transferred to the extract of these plants is relatively low, resulting in little ingestion of these elements by the population during the extract consumption. (author)

  3. Rare Earth and other Chemical Elements Accumulation in Vines of Fogo Island (Cape Verde)

    Science.gov (United States)

    Marques, Rosa; Prudêncio, Maria Isabel; Rocha, Fernando; Dias, Maria Isabel; Franco, Dulce

    2017-04-01

    The Fogo Island is the fourth bigger island of the Cape Verde (central Atlantic Ocean). This archipelago is located 570 kilometres off the coast of West Africa, and is characterized by a semi-arid climate. The volcanic soils of the caldera of this island, with an active volcanism during historical times, have been used for viticulture. The study of uptake of chemical elements by vines - absorption and translocation to grapes - grown in soils developed on alkaline pyroclasts is the main goal of this work. The concentrations of 27 chemical elements in bark, leafs and grapes of two vines, as well as in the corresponding soils (core grid of the Portuguese Research Reactor (CTN/IST, Bobadela). The distribution patterns of the enrichment factors (EF) in the different parts of the plants are similar for the two sampling sites. Significant EF were found for the majority of the chemical elements studied, in the several parts of the plants, particularly in grapes where Cr, As, Sb and U are accumulated (EF > 50). The bioavailable fraction of Cr and As in these soils may be due to the low percentage of iron oxides (particularly in the form of nanoparticles), which play an important role in the retention of these elements. The factors responsible for the phytoavailability of Sb in soils and its uptake by plants it's still poorly known. Although the Sb concentrations in earth's crust are low, higher concentrations of this element in soils may be related with hydrothermal and volcanic processes. Also, the temperature may influence the accumulation of Sb in plants, with an increase of the Sb uptake by plants at higher temperatures, due to an increased desorption rate of Sb from soil particles. Concerning U, its mobility and dispersion in soils is controlled by its oxidation state, its adsorption capacity in clay minerals or iron oxides, and the ability to form more or less soluble complexes. Although U concentrations in these volcanic soils are low, there is a fraction available

  4. Systematic study on Thorium fuel

    International Nuclear Information System (INIS)

    Shibata, Toshikazu; Kimura, Itsuro; Iwata, Shiro; Furuya, Hirotaka; Suzuki, Susumu.

    1988-01-01

    Introduced is the activities of the Joint Research Project Team on Thorium Fuel organized by mainly university researchers in Japan and supported by the Ministry of Education, Science and Culture for seven years since 1980. Four major groups were organized; (1) nuclear data, reactor physics and design, (2) nuclear fuel, (3) down stream and (4) biological effects of thorium. The first group covered measurements and analysis on nuclear data of thorium related nuclides, experiment and analysis on nuclear characteristics of thorium containing cores, basic engineering on a thorium molten salt reactor, and designs of several types of reactors. Fabrication and irradiation tests of thorium oxide fuel, and basic studies on new type thorium fuels (e.g. carbide and nitride) were studied by the second group. The third group covered the use of solutions in reprocessing of spent fuel, behavior of fission products, immobilization of high level radioactive waste, and continuous reprocessing for a molten salt reactor. The fourth group performed the trace study for patients who had been intravascularly injected with thorotrast for diagnosis of war injuries during the Second World War. (author)

  5. Notes on Contributions to the Science of Rare Earth Element Enrichment in Coal and Coal Combustion Byproducts

    Directory of Open Access Journals (Sweden)

    James C. Hower

    2016-03-01

    Full Text Available Coal and coal combustion byproducts can have significant concentrations of lanthanides (rare earth elements. Rare earths are vital in the production of modern electronics and optics, among other uses. Enrichment in coals may have been a function of a number of processes, with contributions from volcanic ash falls being among the most significant mechanisms. In this paper, we discuss some of the important coal-based deposits in China and the US and critique classification systems used to evaluate the relative value of the rare earth concentrations and the distribution of the elements within the coals and coal combustion byproducts.

  6. Luminescence of Lanthanoides (Rare-earth elements) – Probes of structural variations in minerals

    International Nuclear Information System (INIS)

    Lenz, C.

    2015-01-01

    This cumulative PhD thesis summarises several individual studies on the luminescence of REE (rare-earth elements; i.e., trivalent lanthanoides), which are typically incorporated in accessory minerals such as zircon, titanite, monazite–(Ce) and xenotime–(Y). A main objective of these studies is to examine the powerfulness of REE luminescence-spectroscopy as structural probe. In particular, this concerns the potential use of REE3+ emissions in characterising structural disorder of their accessory host minerals as caused by radiation damage and/or compositional heterogeneity. Especially the former (i.e., mineral disorder due to radiation damage) is of interest to Earth and materials scientists, for instance for the understanding of changed physicochemical properties of initially crystalline materials that are affected by structural damage as caused by the radioactive decay of actinides. Moreover, a substantial contribution of the studies presented lies in the field of basic properties of the REE luminescence of natural accessory minerals. First, the investigations have addressed the identification of diverse REE species in diverse natural host minerals (which is done using synthetic REE-doped analogues). Second, factors that may bias the quantitative estimation of spectroscopic parameters have been studied, including effects of experimental parameters (crystal orientation and temperature) and the samples’ compositional heterogeneity. The results will be particularly useful to the growing community of Earth scientists who apply REE luminescence-spectroscopy in studying geological materials. (author) [de

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

    Science.gov (United States)

    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

  8. Transportation of natural radionuclides and rare earth light elements in the lagoon system of Buena, RJ

    International Nuclear Information System (INIS)

    Lauria, Dejanira da Costa

    1999-03-01

    it was investigated the transport of the series natural radionuclides and the earth rare light elements in a coastal lagoon system, located in a monazite rich region, in the coast north region of Rio de Janeiro state. The lagoon water showed off abnormal concentrations of radium isotopes and of the earth rare light elements (ERLEs). The longitudinal gradient of the Ra, of the ERLEs and of the major ion concentration's, whose data were obtained during two and half years of the research at the place, and the statistical analysis pointed to two mainly source as responsible for the water lagoon composition - the marine and the underground waters. The underground water supplies the radionuclides and ERLEs, possibly originated by monazite lixiviation. Based on the water speciation modeling, the results of laboratory adsorption on sediment experiments and the sediment characterization, the behavior of the radio isotopes, the ERLEs, U, Th e Pb-210, along of the lagoon, are discussed. It is also discussed the role of the aquatic macrophyte Typha dominguesis Pers in the nuclide uptake and the following liberation. (author)

  9. Rare earth elements tracing the soil erosion processes on slope surface under natural rainfall

    International Nuclear Information System (INIS)

    Zhu Mingyong; Tan Shuduan; Dang Haishan; Zhang Quanfa

    2011-01-01

    A field experiment using rare earth elements (REEs) as tracers was conducted to investigate soil erosion processes on slope surfaces during rainfall events. A plot of 10 m x 2 m x 0.16 m with a gradient of 20 o (36.4%) was established and the plot was divided into two layers and four segments. Various REE tracers were applied to the different layers and segments to determine sediment dynamics under natural rainfall. Results indicated that sheet erosion accounted for more than 90% of total erosion when the rainfall amount and density was not large enough to generate concentrated flows. Sediment source changed in different sections on the slope surface, and the primary sediment source area tended to move upslope as erosion progressed. In rill erosion, sediment discharge mainly originated from the toe-slope and moved upwards as erosion intensified. The results obtained from this study suggest that multi-REE tracer technique is valuable in understanding the erosion processes and determining sediment sources. - Highlights: → Soil erosion processes with rare earth elements was conducted under natural rainfall. → Experimental setup developed here has seldom implemented in the world. → Sheet erosion is the main erosion type and main contributor to sediment loss. → Sediment source changed in different sections on the slope surface. → The primary sediment source area tended to move upslope as erosion progressed.

  10. Characterization of Rare Earth Elements in in Clay Deposits Associated with Central Appalachian Coal Seams

    Science.gov (United States)

    Scott, M.; Verba, C.; Falcon, A.; Poston, J.; McKoy, M.

    2017-12-01

    Because of their multiple uses in clean energy technologies, rare earth elements (REE) are critical for national economic and energy security. With no current domestic source, supply remains a major concern for domestic security. Underclay - specifically the layer of stratum beneath a coal bed - is a potentially rich source of REE. This study focuses on the characterization and ion exchange recovery of REE from underclay samples from the Lower Freeport, Middle Kittanning, and Pittsburgh coal seams in West Virginia. Multimodal techniques provided quantitative assessments of REE-bearing mineral phases in select underclays and the influence of organic acid rock treatment on the recovery of REE from both exchangeable and crystalline mineral phases present. All samples are from extensively weathered horizons that contain abundant kaolinite and illite. Total REE concentrations range from 250-450 ppm and all samples have a HREE/LEEE ratio >20%. Rare earth element bearing minerals identified in the clay are monazite, xenotime, florencite, and crandallite. Our selective recovery approach is designed to isolate and recover REE through partial dissolution of the clay matrix and ion exchange rather than dissolution/recovery of phosphate or aluminosilicate bound REE. These results provide a better understanding of coal seam underclay, the affinity of REEs for specific ligands and colloids, and how the rock and ligands respond to different chemical treatments. These processes are important to the development and commercialization of efficient and cost effective methods to extract REE from domestic geologic deposits and recover into salable forms.

  11. Rare earth element composition of Paleogene vertebrate fossils from Toadstool Geologic Park, Nebraska, USA

    Energy Technology Data Exchange (ETDEWEB)

    Grandstaff, D.E., E-mail: grand@temple.edu [Department of Earth and Environmental Science, Temple University, Philadelphia, PA 19122 (United States); Terry, D.O. [Department of Earth and Environmental Science, Temple University, Philadelphia, PA 19122 (United States)

    2009-04-15

    Fossil bones and teeth from terrestrial environments encode unique rare earth and trace element (REE and TE) signatures as a function of redox conditions, pH, concentrations of complexing ligands, and water-colloid interactions. This signature is set early in the fossilization process and serves as a paleoenvironmental and paleoclimatic proxy. These signatures can also be used to interpret temporal and spatial averaging within vertebrate accumulations, and can help relocate displaced fossil bones back into stratigraphic context. Rare earth elements in vertebrate fossils from upper Eocene and Oligocene strata of Toadstool Geologic Park, northwestern Nebraska, record mixing and evolution of Paleogene vadose or groundwaters and variations in paleoenvironments. REE signatures indicate that HREE-enriched alkaline groundwater reacted with LREE- and MREE-enriched sediments to produce 3-component mixtures. REE signatures become increasingly LREE- and MREE-enriched toward the top of the studied section as the paleoenvironment became cooler and drier, suggesting that REE signatures may be climate proxies. Time series analysis suggests that REE ratios are influenced by cycles of ca. 1050, 800, 570, 440, and 225 ka, similar to some previously determined Milankovitch astronomical and climate periodicities.

  12. Effects of Rare Earth Elements on Properties of Ni-Base Superalloy Powders and Coatings

    Directory of Open Access Journals (Sweden)

    Chunlian Hu

    2017-02-01

    Full Text Available NiCrMoY alloy powders were prepared using inert gas atomization by incorporation of rare earth elements, such as Mo, Nb, and Y into Ni60A powders, the coatings were sprayed by oxy-acetylene flame spray and then remelted with high-frequency induction. The morphologies, hollow particle ratio, particle-size distribution, apparent density, flowability, and the oxygen content of the NiCrMoY alloy powders were investigated, and the microstructure and hardness of the coatings were evaluated by optical microscopy (OM. Due to incorporation of the rare earth elements of Mo, Nb, or Y, the majority of the NiCrMoY alloy particles are near-spherical, the minority of which have small satellites, the surface of the particles is smoother and hollow particles are fewer, the particles exhibit larger apparent density and lower flowability than those of particles without incorporation, i.e., Ni60A powders, and particle-size distribution exhibits a single peak and fits normal distribution. The microstructure of the NiCrMoY alloy coatings exhibits finer structure and Rockwell hardness HRC of 60–63 in which the bulk- and needle-like hard phases are formed.

  13. Investigation on the status of rare earth elements contained in the powder of spent fluorescent lamps

    Energy Technology Data Exchange (ETDEWEB)

    Belardi, G. [Institute of Environmental Geology and Geoengineering (CNR) Area della Ricerca CNR, via Salaria km 29300, Monterotondo, Rome 00016 (Italy); Ippolito, N. [Department of Chemical Engineering, Materials and Environment, Sapienza University of Rome, via Eudossiana 84, Rome 00184 (Italy); Piga, L., E-mail: luigi.piga@uniroma1.it [Department of Chemical Engineering, Materials and Environment, Sapienza University of Rome, via Eudossiana 84, Rome 00184 (Italy); Serracino, M. [Institute of Environmental Geology and Geoengineering (CNR) Area della Ricerca CNR, via Salaria km 29300, Monterotondo, Rome 00016 (Italy)

    2014-09-10

    Highlights: • Most of rare earth elements are contained in particles of size finer than 7 μm. • Most of Si, K and Na are contained in the coarser size-fractions. • The phases in the size-fractions of the fluorescent powder have been determined. • Europium is contained in yttrium oxide and in vanadium–yttrium oxides. • The crystallo–chemical composition of all the phases has been determined. - Abstract: The aim of this study is to examine the status of rare earth elements (REE) contained in the chemical compounds that make up the powder of spent fluorescent lamps, with a view of their recovery. The status of REE in the as-received powder, as well as in a few size-class fractions of it, has been established. This way, only those size-class fractions containing high REE concentrations can be considered in a recovery process. The investigation has been carried out using particle-size, chemical, TGA/DTA, XRPD, SEM-EDS and EMPA analyses. The last technique enabled to establish the status of REE within the lattice of the chemical compounds present in the powder. The fineness of the as-received powder and the higher REE concentration in the finest size-classes suggest that physical methods of separation should not be used to separate the REE-containing chemical compounds from each other. Leaching methods seem more suitable with a material of such size.

  14. Spectrographic analysis of thorium and its compounds

    International Nuclear Information System (INIS)

    Grampurohit, S.V.; Saksena, M.D.; Kaimal, V.N.P.; Kapoor, S.K.; Murty, P.S.

    1980-01-01

    A spectrographic method, which employs the principle of carrier-distillation technique, is described for the analysis of high purity thoria. Two carriers, AgCl and NaF were used in determining 27 trace elements in ThO 2 . The elements were divided into three groups, A, B and C. In group A, 15 elements, viz. Al, B, Be, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sb, Si and Sn were included since it was possible to choose sensitive lines of these elements in one spectral region, 220 - 285 nm. Group B covered 8 elements, viz. Ag, Bi, Ca, Ga, Mo, Ti, V and Zn, which could be determined in the spectral region 290 - 352.5 nm. Group C consisted 4 elements, viz. Ba, K, Li and Na which could be determined in the spectral region 440 - 820 nm. 5% AgCl was used as the carrier for the determination of groups A and C elements and 4% NaF was used as the carrier for the estimation of group B elements. One hundred milligrammes of the sample (in the form of ThO 2 ) containing the carrier were taken in a carrier-distillation electrode and excited in a d.c. arc (10 amps for groups A and C; 15 amps for group B). The spectra of sample and synthetic standards were photographed on Hilger's large quartz, JACO 3.4 m Ebert plane grating and Higler's large glass spectrographs respectively for determining group A, B and C elements. The detection limit obtained for B and Cd was 0.1 ppm. Thorium metal and thorium nitrate samples were converted to ThO 2 prior to analysis. (auth.)

  15. Recovery of rare earth elements from the sulfothermophilic red alga Galdieria sulphuraria using aqueous acid.

    Science.gov (United States)

    Minoda, Ayumi; Sawada, Hitomi; Suzuki, Sonoe; Miyashita, Shin-ichi; Inagaki, Kazumi; Yamamoto, Takaiku; Tsuzuki, Mikio

    2015-02-01

    The demand for rare earth elements has increased dramatically in recent years because of their numerous industrial applications, and considerable research efforts have consequently been directed toward recycling these materials. The accumulation of metals in microorganisms is a low-cost and environmentally friendly method for the recovery of metals present in the environment at low levels. Numerous metals, including rare earth elements, can be readily dissolved in aqueous acid, but the efficiency of metal biosorption is usually decreased under the acidic conditions. In this report, we have investigated the use of the sulfothermophilic red alga Galdieria sulphuraria for the recovery of metals, with particular emphasis on the recovery of rare earth metals. Of the five different growth conditions investigated where G. sulphuraria could undergo an adaptation process, Nd(III), Dy(III), and Cu(II) were efficiently recovered from a solution containing a mixture of different metals under semi-anaerobic heterotrophic condition at a pH of 2.5. G. sulphuraria also recovered Nd(III), Dy(III), La(III), and Cu(II) with greater than 90% efficiency at a concentration of 0.5 ppm. The efficiency remained unchanged at pH values in the range of 1.5-2.5. Furthermore, at pH values in the range of 1.0-1.5, the lanthanoid ions were collected much more efficiently into the cell fractions than Cu(II) and therefore successfully separated from the Cu(II) dissolved in the aqueous acid. Microscope observation of the cells using alizarin red suggested that the metals were accumulating inside of the cells. Experiments using dead cells suggested that this phenomenon was a biological process involving specific activities within the cells.

  16. Thorium oxalate solubility and morphology

    International Nuclear Information System (INIS)

    Monson, P.R. Jr.; Hall, R.

    1981-10-01

    Thorium was used as a stand-in for studying the solubility and precipitation of neptunium and plutonium oxalates. Thorium oxalate solubility was determined over a range of 0.001 to 10.0 in the concentration parameter [H 2 C 2 O 4 ]/[HNO 3 ] 2 . Morphology of thorium oxide made from the oxalate precipitates was characterized by scanning electron microscopy. The different morphologies found for oxalate-lean and oxalate-rich precipitations were in agreement with predictions based on precipitation theory

  17. Computer simulations for thorium doped tungsten crystals

    Energy Technology Data Exchange (ETDEWEB)

    Eberhard, Bernd

    2009-07-17

    Tungsten has the highest melting point among all metals in the periodic table of elements. Furthermore, its equilibrium vapor pressure is by far the lowest at the temperature given. Thoria, ThO{sub 2}, as a particle dopant, results in a high temperature creep resistant material. Moreover, thorium covered tungsten surfaces show a drastically reduced electronic work function. This results in a tremendous reduction of tip temperatures of cathodes in discharge lamps, and, therefore, in dramatically reduced tungsten vapor pressures. Thorium sublimates at temperatures below those of a typical operating cathode. For proper operation, a diffusional flow of thorium atoms towards the surface has to be maintained. This atomic flux responds very sensitively on the local microstructure, as grain boundaries as well as dislocation cores offer ''short circuit paths'' for thorium atoms. In this work, we address some open issues of thoriated tungsten. A molecular dynamics scheme (MD) is used to derive static as well as dynamic material properties which have their common origin in the atomistic behavior of tungsten and thorium atoms. The interatomic interactions between thorium and tungsten atoms are described within the embedded atom model (EAM). So far, in literature no W-Th interaction potentials on this basis are described. As there is no alloying system known between thorium and tungsten, we have determined material data for the fitting of these potentials using ab-initio methods. This is accomplished using the full potential augmented plane wave method (FLAPW), to get hypothetical, i.e. not occurring in nature, ''alloy'' data of W-Th. In order to circumvent the limitations of classical (NVE) MD schemes, we eventually couple our model systems to external heat baths or volume reservoirs (NVT, NPT). For the NPT ensemble, we implemented a generalization of the variable cell method in combination with the Langevin piston, which results in a

  18. Computer simulations for thorium doped tungsten crystals

    International Nuclear Information System (INIS)

    Eberhard, Bernd

    2009-01-01

    Tungsten has the highest melting point among all metals in the periodic table of elements. Furthermore, its equilibrium vapor pressure is by far the lowest at the temperature given. Thoria, ThO 2 , as a particle dopant, results in a high temperature creep resistant material. Moreover, thorium covered tungsten surfaces show a drastically reduced electronic work function. This results in a tremendous reduction of tip temperatures of cathodes in discharge lamps, and, therefore, in dramatically reduced tungsten vapor pressures. Thorium sublimates at temperatures below those of a typical operating cathode. For proper operation, a diffusional flow of thorium atoms towards the surface has to be maintained. This atomic flux responds very sensitively on the local microstructure, as grain boundaries as well as dislocation cores offer ''short circuit paths'' for thorium atoms. In this work, we address some open issues of thoriated tungsten. A molecular dynamics scheme (MD) is used to derive static as well as dynamic material properties which have their common origin in the atomistic behavior of tungsten and thorium atoms. The interatomic interactions between thorium and tungsten atoms are described within the embedded atom model (EAM). So far, in literature no W-Th interaction potentials on this basis are described. As there is no alloying system known between thorium and tungsten, we have determined material data for the fitting of these potentials using ab-initio methods. This is accomplished using the full potential augmented plane wave method (FLAPW), to get hypothetical, i.e. not occurring in nature, ''alloy'' data of W-Th. In order to circumvent the limitations of classical (NVE) MD schemes, we eventually couple our model systems to external heat baths or volume reservoirs (NVT, NPT). For the NPT ensemble, we implemented a generalization of the variable cell method in combination with the Langevin piston, which results in a set of Langevin equations, i.e. stochastic

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

    Science.gov (United States)

    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

  20. Thorium utilization program. Quarterly progress report for the period ending February 28, 1977. [Fuel element crushing, burning; particle classification; solvent extraction; dry solids handling; plant management; HET fuel shipping; HTGR recycle demonstration facility

    Energy Technology Data Exchange (ETDEWEB)

    1977-03-01

    General Atomic Thorium Utilization Program activities progressed on schedule during the quarter, with continuation of the head-end reprocessing equipment testing program. Individual testing of the tertiary, oversize crushers and the screener was completed. Preparation of the equipment for testing as a system is under way. Tests on the tertiary crusher revealed no operating problems. No material holdup areas or bypass of the crushing cavity were detected. The initial issue of a functional level diagram for the Fuel Element Size Reduction System has been prepared for preliminary review. Heat transfer coefficients were calculated from data obtained in six 0.40-m primary burner heatup runs. Six runs were made on the 0.20-m primary burner. Other significant 0.20-m burner work included fabrication and initial testing of an electrical resistance probe bed level sensor and preliminary heat transfer design calculations for determining the cooling requirements to maintain the recycling fines cyclone exit temperature at approximately 500/sup 0/C. The conceptual design of the engineering-scale dissolver-centrifuge for incorporation into the head-end line was completed. Three solvent extraction feed adjustment runs were completed. Two of the runs were representative of the continuous intercycle concentration step. The other run was a continuous operation which utilized leacher product as feed. Progress with dry solids handling component and system testing continues. Efforts were focused on completion of the HET fuel shipping conceptual design report, development of detailed costs, and identification of all system interfaces. The Reprocessing Flowsheet Review and Materials Balance Study of reprocessing head-end and off-gas treatment systems is in technical review.

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

    Science.gov (United States)

    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. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  2. Comparison of element compositions of Venus, Earth, Mars and chondrites in the light of D.I. Mendeleev's Periodic law

    International Nuclear Information System (INIS)

    Chuburkov, Yu.T.

    1999-01-01

    The part of free neutral atoms N 0 of all elements being contained in protoplanet cloud is estimated with regard to their abundance and physicochemical properties. Linear dependence of ratio of volatile and nonvolatile elements in chondrites and in eruptive Earth rocks on N 0 is obtained. Ratios of concentrations of element-analogs with different N 0 in substances of Venus, Earth, Mars and chondrites are compared. Obtained data are an evidence that hypothetical process of magnetic separation in protoplanet cloud has been taken place [ru

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

    Science.gov (United States)

    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.

  4. New properties of thorium tetrabromide

    International Nuclear Information System (INIS)

    Genet, M.; Carlier, R.; Hussonnois, M.; Krupa, J.C.; Delamoye, P.; Guillaumont, R.

    1977-01-01

    Most of already known chemical and physical properties of ThBr 4 have been reviewed and a survey of new properties investigated at I.P.N. and dealing more with nuclear and spectroscopy field is presented. ThBr 4 preparation, single crystal production as well as fluorescent properties are described. Then, nuclear aspect is studied mainly for ThBr 4 response to various charged particles versus energy. Attention is drawn on ThBr 4 performances and limits in heavy ion detection. Self-excited α spectrum of ThBr 4 induced by natural thorium radioactivity is reported. Specific properties of ThBr 4 as a matrix for spectroscopic studies are discussed. Preliminary results about absorption and emission spectra at 4K of ThBr 4 crystal doped with U +4 (1 per mille) are presented. The projects in spectroscopy field using ThBr 4 and other tetravalent actinide dopants (Pa +4 , Np +4 , Pu +4 , etc) are described. Then, theoretical support needed for spectrum interpretation is briefly given. Finally, bibliography about 5 f element spectroscopy in various matrixes is included [fr

  5. The comparison of element composition of Venus, Earth, Mars, and chondrites in the light of the Mendeleev Periodic Law

    International Nuclear Information System (INIS)

    Chuburkov, Yu.T.

    1998-01-01

    The share of free neutral atoms, N 0 , for all elements in Protoplanet nebula has been determined with the account of their abundance and physico-chemical properties. The linear dependence for the ratio of nonvolatile and volatile elements in chondrites and igneous rocks of the Earth on N 0 was obtained. The Mendeleev Periodic Law was used to obtain the proof of the existence of the hypothetical process of element magnetic separation in Protoplanet nebula. To this end the concentration ratios of element-analogous with different N 0 in the matters of Venus, Earth, Mars, and chondrites were compared. The data obtained are sufficient demonstration of the existence of the hypothetical process of element magnetic separation in Protoplanet nebula. With the account of the above said, it was shown that Shergotty and Tunguska meteorites by their relative elemental composition are close to Mars and asteroids, respectively. (author)

  6. Experiences in running solvent extraction plant for thorium compounds [Paper No. : V-5

    International Nuclear Information System (INIS)

    Gopalkrishnan, C.R.; Bhatt, J.P.; Kelkar, G.K.

    1979-01-01

    Indian Rare Earths Ltd. operates a Plant using thorium concentrates as raw material, employing hydrocarbonate route, for the manufacture of thorium compounds. A small demonstration solvent extraction plant designed by the Chemical Engineering Division, B.A.R.C. is also being operated for the same purpose using a partly purified thorium hydrocarbonate as raw material. In the solvent extraction process, separation of pure thorium is done in mixer settlers using 40% mixture of tri-butyl phosphate in kerosene. Though a comparatively purer raw material of hydrocarbonate than thorium concentrate is used, heavy muck formation is encountered in the extraction stage. Production of nuclear grade thorium oxide has been successful so far as quality is concerned. The quality of thorium nitrate suffers in the yellow colouration and high phosphate content, the former being only partly controlled through the use of pretreated kerosene. When a larger solvent extraction plant is to be designed to use thorium concentrates as raw material, some of the problems encountered will be considered. (author)

  7. Sustainability: role of thorium

    International Nuclear Information System (INIS)

    Stigson, Bjorn Roland

    2015-01-01

    The task to renew the world's energy infrastructure, where fossil fuels account for 80% of supply, is enormous. The two carbon neutral energy sources - renewable and nuclear - should be the base of the world's future energy mix. Nuclear, however, suffers from a bad public opinion and lack of government support in many parts of the world. We can conclude that the world needs an 'on demand' energy source that is affordable, clean, safe and scalable. Thorium energy could be that energy source. It is the most energy dense solution we know, fitting well to the modular and size-constrained requirements of an urbanizing world. No part of society can create a sustainable world on their own and markets are too slow to drive transformational changes. We need new partnerships between governments, business, civil society and academia where each part is delivering on their specific responsibilities and roles

  8. Cracking the Code of Soil Genesis. The Early Role of Rare Earth Elements

    Science.gov (United States)

    Zaharescu, D. G.; Dontsova, K.; Burghelea, C. I.; Maier, R. M.; Huxman, T. E.; Chorover, J.

    2014-12-01

    Soil is terrestrial life support system. Its genesis involves tight interactions between biota and mineral surfaces that mobilize structural elements into biogeochemical cycles. Of all chemical elements rare earth elements (REE) are a group of 16 non-nutrient elements of unusual geochemical similarity and present in all components of the surface environment. While much is known about the role of major nutrients in soil development we lack vital understanding of how early biotic colonization affects more conservative elements such as REE. A highly controlled experiment was set up at University of Arizona's Biosphere-2 that tested the effect of 4 biological treatments, incorporating a combination of microbe, grass, mycorrhiza and uninoculated control on REE leaching and uptake in 4 bedrock substrates: basalt, rhyolite, granite and schist. Generally the response of REE to biota presence was synergistic. Variation in total bedrock chemistry could explain major trends in pore water REE. There was a fast transition from chemistry-dominated to a biota dominated environment in the first 3-4 months of inoculation/seeding which translated into increase in REE signal over time. Relative REE abundances in water were generally reflected in plant concentrations, particularly in root, implying that below ground biomass is the main sync of REE in the ecosystem. Mycorrhiza effect on REE uptake in plant organs was significant and increased with infection rates. Presence of different biota translated into subtle differences in REE release, reveling potential biosignatures of biolota-rock colonization. The results thus bring fundamental insight into early stages non-nutrient cycle and soil genesis.

  9. Thorium Occurrences, Geological Deposits and Resources

    International Nuclear Information System (INIS)

    Barthel, F.H.; Tulsidas, H.

    2014-01-01

    Availability of Thorium: • Monazite production can be used as a measure for Th availability. • Without commercial rare earth requirements recovery of Th from monazite is not economic. • Extraction of Th from deposits containing e.g. Nb,Ta, may become economic by-product once commercial Th requirements progress.• Monazite is extracted in India, Brazil, Malaysia. • Annually 6 300 to 7 400 t monazite between 2004 and 2008. • Largest producer: India, ~5 000 t monazite /a. • Later figures are not available (Chinese competition on the rare earth market?). • Other monazite producers (unknown amounts): China, Indonesia, Nigeria, North and South Korea, CIS. • Theoretical content of Th in the above reported monazite: 300 to 600 t Th. • Th production reported: Brazil, Canada, India and others, details are not available.

  10. Physical properties of thorium fluoride

    International Nuclear Information System (INIS)

    Van Uitert, L.G.; Guggenheim, H.J.; O'Bryan, H.M.; Warner, A.W. Jr.; Brownlow, D.; Bernstein, J.L.; Pasteur, G.A.; Johnson, L.F.

    1976-01-01

    Thorium fluoride has many properties that make it of interest for infrared windows. It is transparent to about eleven microns, is unaffected by moisture, has a moderate hardness, and suffers little dimensional change upon heating

  11. Spectrophotometric method for the determination of thorium in UO2 pellets

    International Nuclear Information System (INIS)

    Acosta L, E.

    1995-04-01

    This report presents a procedure with the description of the spectrophotometric method for the determination of the thorium element in uranium products including powders and pellets of uranium dioxide. Quantities can be determined starting from 1 ppm. (Author)

  12. Phytoextraction of rare earth elements in herbaceous plant species growing close to roads.

    Science.gov (United States)

    Mikołajczak, Patrycja; Borowiak, Klaudia; Niedzielski, Przemysław

    2017-06-01

    The aim of study was to determine the phytoextraction of rare earth elements (REEs) to roots, stems and leaves of five herbaceous plant species (Achillea millefolium L., Artemisia vulgaris L., Papaver rhoeas L., Taraxacum officinale AND Tripleurospermum inodorum), growing in four areas located in close proximity to a road with varied traffic intensity. Additionally, the relationship between road traffic intensity, REE concentration in soil and the content of these elements in plant organs was estimated. A. vulgaris and P. rhoeas were able to effectively transport REEs in their leaves, independently of area collection. The highest content of REEs was observed in P. rhoeas leaves and T. inodorum roots. Generally, HREEs were accumulated in P. rhoeas roots and leaves and also in the stems of T. inodorum and T. officinale, whereas LREEs were accumulated in T. inodorum roots and T. officinale stems. It is worth underlining that there was a clear relationship between road traffic intensity and REE, HREE and LREE concentration in soil. No positive correlation was found between the concentration of these elements in soil and their content in plants, with the exception of T. officinale. An effective transport of REEs from the root system to leaves was observed, what points to the possible ability of some of the tested plant species to remove REEs from soils near roads.

  13. Bio sorption of some Rare Earth Elements and Yttrium by Gram Positive and Gram Negative Bacteria

    International Nuclear Information System (INIS)

    Ibrahim, H.A.

    2012-01-01

    The separate bio sorption of the REEs La, Sm, Eu and Dy together with yttrium upon the Gram positive bacteria Bacillus subtilis (B.subtilis) and Bacillus Licheniformis (B. Licheniformis),the Gram negative bacterium Escherichia coli (E. coli ) and Saccharomyces cervisiae (Yeast) was studied. The revelant factors of ph 1-6, contact time (30-180 min), the initial rare earth concentration (50-200 mg/l) have been studied. The amount of the accumulated element was strongly affected by its concentration.In addition, bio sorptive fractionation of Y and the studied REEs from a solution containing a mixture of these elements was also studied. From the obtained data, it was found that Langmuir isotherm model for both B.licheniformis and E.coli gives a best fit for the studied elements over the working range of concentration (50-200 mg/I). Transmission electron microscopy exhibited accumulation throughout the bacterial cell with some granular deposits in both the cell periphery and cytoplasm

  14. Geology of Cerro Carmen prospect; uranium and rare earth element mineralization

    International Nuclear Information System (INIS)

    Fortin Medina, Heriberto; Alarcon Farias, Boris

    2008-01-01

    The prospect Cerro Carmen is an skarn deposit with uranium (U) and Rare Earth Elements (REE )hosted in intermediate to basic volcanic rocks. The associated elements involved are Th, Ti, Fe, Y and Sc. The main mineral specie is davidite, it represent a formation temperature near to 1500 o C. The first radiometric anomalies of this prospect were discovered through aerial radiometric survey in 1982, latter in 1995, the interest expressed by Empresa Nacional de Mineria (ENAMI) and CCHEN, on REE and Uranium elements, resulted in the sign of an agreement between both parties to study this prospect,in which ENAMI provided operational resources and CCHEN provided professional resources. From geological point of view, the prospect is located at contact of volcanic rocks, that correspond to La Negra Formation of Pliensbachiano age to upper Jurassic age, with igneous rocks of Pluton Sierra Aspera of Neocomian age, in a structural lineament NW with emplacements of monzonitic and aplitic intrusive rocks from upper Cretaceous age with potassium metasomatism and mineralization of U and REE. In III and IV Regions, similar mineralization to the described one, marks a regional lineament coincidental with the axis of the iron metallogenic province, supporting the need to realize studies to improve the estimation of the potential of radioactive minerals of the country

  15. Atomization of thorium in a hollow-cathode type discharge

    International Nuclear Information System (INIS)

    Pianarosa, P.; Demers, Y.; Gagne, J.M.

    1984-01-01

    The atomization of thorium metal in a hollow-cathode electrical discharge has been investigated. Laser absorption spectroscopy with the laser tuned on the 5760.55 A (0-17355 1 cm -1 ) transition of Th I was used to evaluate the density of atoms in the 3 F 2 ground state. The results obtained (densities up to 10 13 atoms cm -3 ) show that our discharge tube is a suitable source of thorium metal atoms for laser assisted spectroscopic analysis of this element. (author)

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

    Science.gov (United States)

    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

  17. Microchemical determination of nine rare earth elements in silicate rocks by cation-exchange preconcentration - ion-interaction chromatography

    International Nuclear Information System (INIS)

    Oguma, K.; Sato, K.; Kuroda, R.

    1993-01-01

    A method of applying ion-interaction chromatography to the determination of the rare earth elements in silicate rocks on a 100 to 200 mg sample basis has been developed. The rare earths are first separated as a group from matrices by cation-exchange chromatography in hydrochloric acid-thiocyanate media and isolated in a small, defined volume (3.00 ml). Using fractions of this, on-column concentration of the rare earths on a C-18 bonded phase silica coated with 1-octanesulfonate and a subsequent concentration gradient elution with glycolate (0.05 to 0.35 M) at pH 3.5 allows the respective separation of La, Ce, Pr, Nd, and Y (100 μl aliquot used) and of Er, Tm, Yb, and Lu (2.00 ml aliquot used). Sm, Eu, Gd, Tb, and Dy elute together, and Ho is not sufficiently well resolved from these middle rare earth elements. The eluted rare earth elements are detected and quantified by post-column reaction with Arsenazo III photometrically, using a UV-VIS spectrophotometer at a wavelength of 650 nm. The method is shown to be capable of determining nine of the rare earth elements in a variety of international reference rock samples with good precision and accuracy. (orig.)

  18. Gold, uranium and thorium in zones of greenschist displacement metamorphism

    International Nuclear Information System (INIS)

    Gavrilenko, B.V.; Savitskij, A.V.; Titov, V.V.

    1987-01-01

    Distribution of gold, uranium (bar and mobile) and thorium in 15 zones of greenschist dislocated metamorphism in different structures of the Karelo-Kola region carried out by geologic formations of the Early-Archean-Late-Proterozoic age has been studied. More than 200 samples of well core from 0-200 m depths have been analyzed. The results obtained testify to the increase of gold, uranium and less thorium content in zones of green-schist dislocated metamorphism in comparison with the enclosing rocks 1.4-3.1 times. The variation coefficient of gold, uranium and thorium content in green-schist dislocated tectonites increases 1.5-2.9 times. The correlation coefficient of Au/U mob. pair is +0.69, and Au/U bar pair -+0.87. Essential correlation between concentrations of all three elements in enclosing rocks is absent

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

    Science.gov (United States)

    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. Estimation of rare earth elements in gadolinium oxide by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Kumar, Sanjukta A.; Venkataramani, B.; Kotekar, M.K.

    2007-01-01

    A method was developed for the direct determination of trace quantities of rare earth elements (REEs) in gadolinium oxide dissolved in nitric acid by inductively coupled plasma mass spectrometry. The matrix suppression effect of Gd on the ion peak signals of REEs impurities was effectively compensated with spiking In as an internal standard. The recoveries of spiked sample for REEs were found to be in the range of 91-109% by using the proposed method. The relative standard deviation varied between 1.5 to 6%. The methodology had been found to be suitable for the direct determination of trace REEs in Gd 2 O 3 and the results obtained from this method keep in good agreement with that acquired from inductively coupled plasma emission spectrometry. (author)

  1. Donor centers in irradiated Si doped with rare-earth elements

    International Nuclear Information System (INIS)

    Petrov, V.V.; Prosolovich, V.S.; Tkachev, V.D.; Karpov, Yu.A.; Millvidskii, M.G.

    1985-01-01

    In order to study the participation of rare-earth elements REE in the production of electrically active centers in doped and gamma irradiated silicon the range of REE was expanded to Er, Yb, Gd, Dy, and Ho and a high-temperature treatment was applied to irradiated material. Parallel investigations with Si:B single crystals were carried out. Isochronal annealing was performed in the 50 to 650 0 C range and the annealing curves of charge carrier concentration were obtained and discussed. The kinetics of donor center production in irradiated Si:Er, B upon isothermal annealing was measured for detecting the nature of produced donors. Results give evidence that RE atoms can produce electrically active impurity-defect complexes in silicon

  2. Rare earth elements determination in geological samples by ICP/AES using mini columns

    International Nuclear Information System (INIS)

    Oliveira, Robson Cota de; Boaventura, Geraldo Resende

    1998-01-01

    The determination of the rare earth elements (REE)by a simple, quick and low cost method is presented. The method involves samples decomposition, ion-exchange separation using minicolummns and determinations of REE (La, Ce, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb and Lu) by Inductively Coupled Plasma Atomic Emission Spectroscopy ICP/AES). Geochemical references samples were used for accuracy and precision evaluation. The results are close to the recommended values with relative standard deviations consistent with the literature, demonstrating efficiency, and compatibility with the conventional methods. The recuperation of the heavy REE, Ho, Er, Yb and Lu was 100%, Nd, Sm, Eu, Gd and Dy is 98-99%; Ce is 94% and La 85%. The method allows to analyse 18 samples/hour, representing quick and high performance procedure for geological materials. (author)

  3. Microstructural Characterization of the As-cast AZ91 Magnesium Alloy with Rare Earth Elements

    Directory of Open Access Journals (Sweden)

    A. Grzybowska

    2012-12-01

    Full Text Available Microstructural analysis of as-cast Mg-9Al-0.9Zn-xRE (x = 0, 1, 2, 3, 5 wt.% magnesium alloys is presented. Light microscopy (LM andscanning electron microscopy (SEM+EDX were used to characterized the obtained material. The results revealed that the as-cast AZ91alloy consists of α – Mg matrix, binary eutectic  +  (where  is Mg17Al12. While rare earth elements were introduced to the Mg-Al-Znalloy new Al11RE3 phase was formed. Additionally, in the experimental alloys instead of Al-Mn phase, ternary Al-Mn-RE compound was observed. What is more, the influence of RE addition on the area fraction of eutectic and needle-like phase was analysed. With increasing addition of RE, the amount of γ phase decreased, but the amount of Al11RE3 phase increased.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    International Nuclear Information System (INIS)

    Scott A. Wood

    2002-01-01

    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

  6. Rare earth elements distribution in clay zones of sedimentary formation, Pondicherry, south India

    International Nuclear Information System (INIS)

    Tirumalesh, K.; Gursharan Singh

    2012-01-01

    Concentrations of five rare earth elements (REE) were measured in clay samples of a deep bore hole comprising major aquifers of Pondicherry region, south India in order to investigate the geochemical variations among various litho-units. Clay samples from Cretaceous formation show distinct gray to black color whereas Tertiary deposits have clays with color varying from pale yellow to brown to gray. All measured REEs exhibit lower concentrations than Upper Continental Crust (UCC) average values. Large variations in REEs contents were observed in different sedimentary formations (Tertiary and Cretaceous). Chondrite normalized ratio of La/Lu and Eu/Eu* indicate that the clays are derived from weathering of felsic rock and possibly under humid climate. All the samples showed positive Eu anomaly in North American Shale Composite (NASC) normalized plot which shows plagioclase feldspar as the major contributor to these clays. Positive Eu anomaly is also an indication of reduced condition of the formation. (author)

  7. The rare earth element (REE) lanthanum (La) induces hormesis in plants.

    Science.gov (United States)

    Agathokleous, Evgenios; Kitao, Mitsutoshi; Calabrese, Edward J

    2018-03-14

    Lanthanum is a rare earth element (REE) which has been extensively studied due to its wide application in numerous fields with a potential accumulation in the environment. It has long been known for its potential to stimulate plant growth within a hormetic-biphasic dose response framework. This article provides evidence from a series of high resolution studies published within the last two decades demonstrating a substantial and significant occurrence of lanthanum-induced hormesis in plants. These findings suggest that hormetic responses should be built into the study design of hazard assessment study protocols and included in the risk assessment process. Hormesis also offers the opportunity to substantially improve cost benefit estimates for environmental contaminants, which have the potential to induce beneficial/desirable effects at low doses. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  10. Rare earth elements in human hair from a mining area of China.

    Science.gov (United States)

    Wei, Binggan; Li, Yonghua; Li, Hairong; Yu, Jiangping; Ye, Bixiong; Liang, Tao

    2013-10-01

    Rare earth minerals have been mined for more than 50 years in Inner Mongolia of China. In the mining area rare earth elements (REE) may be significantly accumulated in humans. Therefore, the aim of this paper is to characterize the REE concentrations in hair of local residents. REE concentrations in hair of 118 subjects were determined. The results showed that the mean concentrations of the determined REE in the hair of both females and males were usually higher from mining area than from control area. The mean concentrations of all the fifteen REE were much higher in hair of males than in hair of females from mining area. This suggested that males might be more sensitive to REE than females. In addition, the mean contents of the REE in hair of miners, particularly light REE (La, Ce, Pr and Nd), were usually much higher than the values in hair of non-miners from both mining area and control area, indicating that the miners were exposed to higher concentrations of REE in occupational environment. Among age groups, the relationships between REE concentrations and age groups showed that more and more concentrations of light REE accumulated in body of both females and males with age until 60 years, while heavy REE concentrations decreased with age in males who were exposed to low concentrations of heavy REE. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Rare earth elements and hypertension risk among housewives: A pilot study in Shanxi Province, China.

    Science.gov (United States)

    Wang, Bin; Yan, Lailai; Huo, Wenhua; Lu, Qun; Cheng, Zixi; Zhang, Jingxu; Li, Zhiwen

    2017-01-01

    Studies have shown that residents living near rare earth mining areas have high concentrations of rare earth elements (REEs) in their hair. However, the adverse effects of REEs on human health have rarely been the focus of epidemiological studies. The goal of this study was to evaluate the relationship between REEs in hair and the risk of hypertension in housewives. We recruited 398 housewives in Shanxi Province, China, consisting of 163 women with hypertension (cases) and 235 healthy women without hypertension (controls). We analyzed 15 REEs (lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), Yttrium (Y), cerium (Ce), praseodymium (Pr), and neodymium (Nd)) and calcium (Ca) accumulated in housewives hair over a period of two years. The results revealed that, with the exception of Eu, concentrations of the REEs in hair were higher in the cases than in the controls. The univariate odds ratios (ORs) of the 14 REEs were >1, and four of the REEs (Dy, Tm, Yb, and Y) also had adjusted ORs > 1. The increasing dose-response trends of the four REEs further indicated the potential for increased hypertension risk. Moreover, the REEs were negatively correlated with Ca content in hair. These results might suggest an antagonistic effect of REEs on Ca in the human body. It was concluded that high intake of REEs might increase the risk of hypertension among housewives. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Rare earth elements-critical resources for green energy and digital technology

    International Nuclear Information System (INIS)

    Singh, D.

    2013-01-01

    High technology and environment applications of the Rare Earth Elements (REE) have grown dramatically in diversity and importance over the past few decades. The REE forms largest economical coherent group in the periodic table. The versatility and specialty of the REE has given them a level of technological, environment and economical importance. As technological applications of REE have multiplied over the past several decades, the demand for them has increased dramatically. The green energy is the segment, which is largely contributed in its performance by the REE. The increasing concern about the impact of green house gases around the globe has made countries to explore clean energy technologies to reduce emissions. India has ambitious plans for generating solar power of 30,000 MW and wind energy of 50,000 MW by 2013. Critical component with respect to wind energy is the high strength rare earth permanent magnet, while in hybrid electrical motors REEs like lanthanum are used in LiMH battery pack

  13. Rare earth elements in Holocene reefal microbialites: a new shallow seawater proxy

    Science.gov (United States)

    Webb, Gregory E.; Kamber, Balz S.

    2000-05-01

    The concentration of rare earth elements and yttrium (REE + Y) was determined in Holocene Mg-calcite microbialites from shallow reef framework cavities at Heron Reef, Great Barrier Reef. Shale-normalized REE + Y patterns of 52 microbialite samples show: (1) uniform heavy REE enrichment (Nd SN/Yb SN = 0.236, SD = 0.026); (2) consistent negative Ce and positive La anomalies; (3) marine Y/Ho ratios (56.17, SD = 2.66); and (4) slightly positive Gd anomalies. All of these features are consistent with the geochemistry of well-oxygenated, shallow ambient seawater. REE partition coefficients were calculated relative to shallow Coral Sea seawater. They are uniform (relative SD = 10.2%) across the entire mass range and almost two orders of magnitude higher than those between coral and seawater. Hence, terrigenous detritus-free, modern microbialites are a more reliable proxy for seawater REE chemistry than are skeletal carbonates. Ancient limestones have been considered largely problematic as sources for REE proxies owing to perceived problems with diagenesis, partly on the basis of relatively high REE concentrations in some limestones compared to modern skeletal carbonates. However, high REE concentrations in modern microbialites suggest that ancient limestones with relatively high REE concentrations, if not contaminated by terrigenous detritus, may reflect original seawater chemistry. Terrigenous contamination, if present, is readily detectable on the basis of co-occurring trace element concentrations (Sc, Hf, Th) and Y/Ho ratio. Hence, ancient, particularly reefal, limestones may provide reliable seawater REE proxies. The occurrence of microbialites in clean limestones as old as 3.5 Ga suggests the possibility of reconstructing shallow marine REE chemistry over most of Earth history with important implications for paleogeography and paleoredox studies.

  14. Evaluation of rare earth elements in groundwater of Lagos and Ogun States, Southwest Nigeria.

    Science.gov (United States)

    Ayedun, H; Arowolo, T A; Gbadebo, A M; Idowu, O A

    2017-06-01

    Rare earth elements in our environment are becoming important because of their utilization in permanent magnets, lamp phosphors, superconductors, rechargeable batteries, catalyst, ceramics and other applications. This study was conducted to evaluate the level of rare earth elements (REE) and the variability of their anomalous behavior in groundwater samples collected from Lagos and Ogun States, Southwest, Nigeria. REE concentrations were determined in 170 groundwater samples using inductively coupled plasma-mass spectrometry, while the physicochemical parameters were determined using standard methods. Lagos State groundwater is enriched with REE [sum REEs range (mean ± SD)]; [0.365-488 (69.5 ± 117)] µg L -1 than Ogun State groundwater [sum REEs range (mean ± SD)]; [1.14-232 (22.6 ± 41.1)] µg L -1 . Boreholes are more enriched with REEs than wells. Significant (P < 0.05) positive correlation (R = Pearson) was recorded in Lagos State groundwater between sum REEs and Fe (R = 0.55). However, there were no significant correlations between sum REEs, pH (R = 0.073) and HCO 3 2- (R = 0.157) in Ogun State groundwater. Chondrite-normalized plot shows that Lagos groundwater exhibits positive Ce anomaly, while Ogun State groundwater does not. The source of REE in Lagos State may be from the ocean and leaching from wastes dumpsites, while the source in Ogun State groundwater may be from the rocks.

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

    Science.gov (United States)

    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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Natural radioactivity and Rare Earth elements in feldspar samples, Central Eastern desert, Egypt

    Energy Technology Data Exchange (ETDEWEB)

    Walley El-Dine, Nadia, E-mail: nadia_walley5@hotmail.co [Department of physics, Faculty of girls for Art, Science and Education, Ain Shams University, Heliopolis, Cairo (Egypt); El-Shershaby, Amal [Department of physics, Faculty of girls for Art, Science and Education, Ain Shams University, Heliopolis, Cairo (Egypt); Afifi, Sofia [Nuclear Materials Authority (Egypt); Sroor, Amany; Samir, Eman [Department of physics, Faculty of girls for Art, Science and Education, Ain Shams University, Heliopolis, Cairo (Egypt)

    2011-05-15

    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 150 km{sup 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 {sup 238}U, {sup 232}Th and {sup 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{sup -1} has been observed to be from 9.5 to 183675.7 BqKg{sup -1} for {sup 238}U, between 6.1 and 94,314.2 BqKg{sup -1} for {sup 232}Th and from 0 to 7894.6 BqKg{sup -1} for {sup 40}K. Radium equivalent activities (Ra{sub eq}), dose rate (D{sub R}) and external hazard (H{sub 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.

  17. Sources and distribution of yttrium and rare earth elements in surface sediments from Tagus estuary, Portugal.

    Science.gov (United States)

    Brito, Pedro; Prego, Ricardo; Mil-Homens, Mário; Caçador, Isabel; Caetano, Miguel

    2018-04-15

    The distribution and sources of yttrium and rare-earth elements (YREE) in surface sediments were studied on 78 samples collected in the Tagus estuary (SW Portugal, SW Europe). Yttrium and total REE contents ranged from 2.4 to 32mg·kg -1 and 18 to 210mg·kg -1 , respectively, and exhibited significant correlations with sediment grain-size, Al, Fe, Mg and Mn, suggesting a preferential association to fine-grained material (e.g. aluminosilicates but also Al hydroxides and Fe oxyhydroxides). The PAAS (Post-Archean Australian Shale) normalized patterns display three distinct YREE fractionation pattern groups along the Tagus estuary: a first group, characterized by medium to coarse-grained material, a depleted and almost flat PAAS-normalized pattern, with a positive anomaly of Eu, representing one of the lithogenic components; a second group, characterized mainly by fine-grained sediment, with higher shale-normalized ratios and an enrichment of LREE relative to HREE, associated with waste water treatment plant (WWTP) outfalls, located in the northern margin; and, a third group, of fine-grained material, marked by a significant enrichment of Y, a depletion of Ce and an enrichment of HREE over LREE, located near an inactive chemical-industrial complex (e.g. pyrite roast plant, chemical and phosphorous fertilizer industries), in the southern margin. The data allow the quantification of the YREE contents and its spatial distribution in the surface sediments of the Tagus estuary, identifying the main potential sources and confirming the use of rare earth elements as tracers of anthropogenic activities in highly hydrodynamic estuaries. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. TerraFERMA: The Transparent Finite Element Rapid Model Assembler for multiphysics problems in Earth sciences

    Science.gov (United States)

    Wilson, Cian R.; Spiegelman, Marc; van Keken, Peter E.

    2017-02-01

    We introduce and describe a new software infrastructure TerraFERMA, the Transparent Finite Element Rapid Model Assembler, for the rapid and reproducible description and solution of coupled multiphysics problems. The design of TerraFERMA is driven by two computational needs in Earth sciences. The first is the need for increased flexibility in both problem description and solution strategies for coupled problems where small changes in model assumptions can lead to dramatic changes in physical behavior. The second is the need for software and models that are more transparent so that results can be verified, reproduced, and modified in a manner such that the best ideas in computation and Earth science can be more easily shared and reused. TerraFERMA leverages three advanced open-source libraries for scientific computation that provide high-level problem description (FEniCS), composable solvers for coupled multiphysics problems (PETSc), and an options handling system (SPuD) that allows the hierarchical management of all model options. TerraFERMA integrates these libraries into an interface that organizes the scientific and computational choices required in a model into a single options file from which a custom compiled application is generated and run. Because all models share the same infrastructure, models become more reusable and reproducible, while still permitting the individual researcher considerable latitude in model construction. TerraFERMA solves partial differential equations using the finite element method. It is particularly well suited for nonlinear problems with complex coupling between components. TerraFERMA is open-source and available at http://terraferma.github.io, which includes links to documentation and example input files.

  19. Hyperspectral REE (Rare Earth Element Mapping of Outcrops—Applications for Neodymium Detection

    Directory of Open Access Journals (Sweden)

    Nina Kristine Boesche

    2015-04-01

    Full Text Available In this study, an in situ application for identifying neodymium (Nd enriched surface materials that uses multitemporal hyperspectral images is presented (HySpex sensor. Because of the narrow shape and shallow absorption depth of the neodymium absorption feature, a method was developed for enhancing and extracting the necessary information for neodymium from image spectra, even under illumination conditions that are not optimal. For this purpose, the two following approaches were developed: (1 reducing noise and analyzing changing illumination conditions by averaging multitemporal image scenes and (2 enhancing the depth of the desired absorption band by deconvolving every image spectrum with a Gaussian curve while the rest of the spectrum remains unchanged (Richardson-Lucy deconvolution. To evaluate these findings, nine field samples from the Fen complex in Norway were analyzed using handheld X-ray fluorescence devices and by conducting detailed laboratory-based geochemical rare earth element determinations. The result is a qualitative outcrop map that highlights zones that are enriched in neodymium. To reduce the influences of non-optimal illumination, particularly at the studied site, a minimum of seven single acquisitions is required. Sharpening the neodymium absorption band allows for robust mapping, even at the outer zones of enrichment. From the geochemical investigations, we found that iron oxides decrease the applicability of the method. However, iron-related absorption bands can be used as secondary indicators for sulfidic ore zones that are mainly enriched with rare earth elements. In summary, we found that hyperspectral spectroscopy is a noninvasive, fast and cost-saving method for determining neodymium at outcrop surfaces.

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

    Science.gov (United States)

    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.

  1. Determination of rare earth elements in geological samples by Icp-OES followed by ion exchange separation (abstract)

    International Nuclear Information System (INIS)

    Ahmad, S.

    2011-01-01

    Present study was carried out to develop a procedure for the chemical separation of rare earth elements (Rees) from major matrix elements using the cation exchange resin column and their quantitative determination by Icp-Oes. The standard reference samples with different concentrations of rare earth elements were prepared using analytical grade standards of rare earth elements (La, Ce, Pr, Nd, Eu, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y) and major matrix elements (Al, B, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Si) in 1n HCl media. Sample solutions were passed through pre equilibrated strongly acidic cation-exchange resin (Dowex 50w X 8). Major matrix elements were eluted with 2n HCl And HNO/sub 3/ whereas Rees (La, Co, Pr, Nd, Eu, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y) were eluted from the resin using 6 To 8n HNO/sub 3/. The proposed method separates the Rees quantitatively from most matrix constituents and greatly facilitates their rapid sequential analysis by ICP-OES. The results revealed usefulness of method for the 95-100% recovery of Rees and their determination up to 0.1 mu g/Ml in solutions of rare earth ores and other geological materials. (author)

  2. Notes on Contributions to the Science of Rare Earth Element Enrichment in Coal and Coal Combustion Byproducts

    OpenAIRE

    James C. Hower; Evan J. Granite; David B. Mayfield; Ari S. Lewis; Robert B. Finkelman

    2016-01-01

    Coal and coal combustion byproducts can have significant concentrations of lanthanides (rare earth elements). Rare earths are vital in the production of modern electronics and optics, among other uses. Enrichment in coals may have been a function of a number of processes, with contributions from volcanic ash falls being among the most significant mechanisms. In this paper, we discuss some of the important coal-based deposits in China and the US and critique classification systems used to eval...

  3. Group separation of rare earth elements by liquid-liquid extraction for the neutron activation analysis of silicate rocks

    International Nuclear Information System (INIS)

    Wyttenbach, A.; Bajo, S.; Tobler, L.

    1983-01-01

    Rare earth elements are isolated as a group from neutron activated rock samples by a new radiochemical procedure based on extraction with thenoyltrifluoracetone/phenanthroline in CHCl 3 . The procedure consists of three extraction steps, obviates the use of inactive carriers and gives practically quantitative chemical yields, thereby avoiding fractionation of the individual rare earths. Details of the dissolution, chemical separations. and counting procedure are given together with an analysis of BCR-1. (author)

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

    Directory of Open Access Journals (Sweden)

    D. N. Brown

    2016-05-01

    Full Text Available 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.

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

    Science.gov (United States)

    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

  6. Subduction Zone Redox and the Deep Earth Cycles of Sulfur and Chalcophile Elements

    Science.gov (United States)

    Canil, D.

    2013-12-01

    Subduction at convergent plate margins is a return flux to the mantle of rocks influenced by weathering, hydrothermal activity, atmospheric exchange, or bio-mineralization in the exosphere. The latter exogenic processes modify the long-term abundance and behaviour of certain elements in the deeper earth that can be traced over time in the chemistry of mantle-derived magmas. The redox budget of subduction is controlled by the flux of oxidized versus reduced forms of Fe, S, H, or C, and impacts the long-term evolution of oxygen on the planet, critical for life in the exosphere. In particular, the sulfur cycle is specifically tied to the evolution of oxygen on Earth's surface over time and critical to biogeochemical cycles on the surface. The behaviour of sulfur in the exogenic system is well-studied and fairly well understood using sedimentary records. An originally sulfidic ocean on Earth gave way with time and oxygenation to one that is sulfate dominated over the last two billion years. In contrast, far less is known of the deep earth cycle of S, and more so its history. The record of the endogenic cycle can only be monitored via what comes out of the mantle (magmas and their gases), or what goes down via subduction (hydrothermally-altered or weathered subducted lithosphere). Interest in the endogenic cycle of S is not new but several outstanding conundrums remain for sulfur in arc magmas that point to the importance of the subduction process. A hitherto ignored component of the paradox of the sulfur cycle is the sedimentary veneer that sits atop the subducted oceanic basalt crust. Compilations show only 0.12 wt% S in altered ocean basalt crust, but up to 10 times that amount in oceanic sediments, tied to their Fe content (in pyrite). These abundances may seem trivial, but the behaviour of this small amount of S in subduction is not fully appreciated and its oxidation potential in the arc mantle is enormous. The conversion of subducted sulfide to sulfate is a 8

  7. Effects of exogenous rare earth elements on phosphorus adsorption and desorption in different types of soils.

    Science.gov (United States)

    Wang, Lingqing; Liang, Tao

    2014-05-01

    Phosphorus (P) is an important biogeochemical element and the environmental fate of P receives increasing attention. Through batch equilibration experiments, the adsorption and desorption of P in the absence and presence of exogeneous rare earth elements (REEs) were investigated in five types of agricultural soil samples collected from China. The results showed that the addition of different doses of REEs had influences on P adsorption processes in the soils, and there were differences in different soil types and different P concentrations of the P solutions. The amount of P adsorption tended to decline when the five types of soils were amended with low concentrations of REEs. The characteristics of P adsorption were more complicated when high concentrations of REEs were added to the different soils. Affected by the high concentrations of REEs, when the P concentration of the P solution added to soils was less than 20 mg L(-1), the rate of P adsorption tended to increase in all the five types of soils. However, when the P concentration of the P solution added to soil was greater than 30 mg L(-1), the rate of P adsorption tended to decrease. The Langmuir equation fitted P adsorption in all the five types of soils well. Compared with the control, when soil samples were amended with REEs, the P desorption rates of the five types of soils increased. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Using rare earth element tracers and neutron activation analysis to study rill erosion process

    International Nuclear Information System (INIS)

    Li Mian; Li Zhanbin; Ding Wengfeng; Liu Puling; Yao Wenyi

    2006-01-01

    Spatially averaged soil erosion data provide little information on the process of rill erosion. The dynamically varied data on the temporal and spatial distributions in the rill erosion process are needed to better understand the erosion process and reveal its innate characteristics. The objectives of this study were to examine the feasibility and effectiveness of rare earth element (REE) tracers and the neutron activation analysis (NAA) method on the study of the rill erosion process and to reveal quantitatively the relationships and characteristics of temporal and spatial distributions of sediment yield in rill erosion. Four REEs were used to study the changeable process of rill erosion at 4 slope positions. Four water inflow rates were applied to a 0.3x5 m soil bed at 3 slopes of 10.5%, 15.8% and 21.2% in scouring experiments. All of the runoff was collected in the experiment. Each sample was air-dried and well mixed. Then 20 g of each sample was sieved through 100-mesh and about a 50 mg sample was weighed for analysis of the four elemental compositions by NAA. Results indicate that the REE tracers and NAA method can be used to not only quantitatively determine soil erosion amounts on different slope segments, but also to reveal the changeable process of rill erosion amount. All of the relative errors of the experimental results were less than 25%, which is considered satisfactory on the study of rill erosion process

  9. Rare-earth elements in refinery cracking catalysts and fuel oils

    International Nuclear Information System (INIS)

    Kitto, M.

    1992-01-01

    This paper reports that nearly all fluid catalytic-cracking units operating at refineries in the U.S. use zeolite catalysts to produce light-weight hydrocarbons, such as fuel oil and gasoline. These petroleum catalysts, typically containing 1-3% rare-earth elements (REEs), have accounted for an average of 40% of the U.S. consumption of REEs in the last 20 years. In a refinery, as the catalyst becomes deactivated (coked) it enters a regenerator, where the coke is oxidized and the flue gases are emitted to the atmosphere. Although refineries regenerate the catalysts many times, annual REE consumption suggests that portions of these catalysts are both discharged to the atmosphere and lost into refined fuels. Fuel combustion dispenses additional REE-containing catalysts into the atmosphere. It thus appears that the unique REE pattern creates an identifiable marker of aerosols containing the cracking catalysts. This study was conducted to determine trace-element composition of cracking catalysts and fuel oils in an effort to compare their REE patterns with emissions from OFPPs and refineries, and recent atmospheric measurements, as well as provide additional composition data for source identification and apportionments. As emission characterizations are difficult and expensive, results from this study can be applied to receptor modeling

  10. Effects of rare earth elements on growth and metabolism of medicinal plants

    Directory of Open Access Journals (Sweden)

    Chunhong Zhang

    2013-02-01

    Full Text Available The rare earth elements (REEs are a set of 17 chemical elements. They include the lanthanide series from lanthanum (La to lutetium (Lu, scandium (Sc, and yttrium (Y in the periodic table. Although REEs are used widely in industry and agriculture in China for a long time, there has been increasing interest in application of REEs to medicinal plants in recent years. In this paper, we summarize researches in the past few decades regarding the effects of REEs on the germination of seeds, the growth of roots, total biomass, and the production of its secondary metabolites, as well as their effects on the absorption of minerals and metals by medicinal plants. By compilation and analysis of these data, we found that REEs have promoting effects at low concentrations and negative effects at comparatively high concentrations. However, most studies focused only on a few REEs, i.e., La, cerium (Ce, neodymium (Nd and europium (Eu, and they made main emphasis on their effects on regulation of secondary metabolism in tissue-cultured plants, rather than cultivated medicinal plants. Advanced research should be invested regarding on the effects of REEs on yields of cultivated plants, specifically medicinal plants.

  11. Modification of Non-Metallic Inclusions by Rare-Earth Elements in Microalloyed Steels

    Directory of Open Access Journals (Sweden)

    M. Opiela

    2012-04-01

    Full Text Available The modification of the chemical composition of non-metallic inclusions by rare-earth elements in the new-developed microalloyed steels was discussed in the paper. The investigated steels are assigned to production of forged elements by thermo- mechanical treatment. The steels were melted in a vaccum induction furnace and modification of non-metallic inclusions was carried out by the michmetal in the amount of 2.0 g per 1 kg of steel. It was found that using material charge of high purity and a realization of metallurgical process in vacuous conditions result in a low concentration of sulfur (0.004%, phosphorus (from 0.006 to 0.008% and oxygen (6 ppm. The high metallurgical purity is confirmed by a small fraction of non-metallic inclusions averaging 0.075%. A large majority of non-metallic inclusions are fine, globular oxide-sulfide or sulfide particles with a mean size 17m2. The chemical composition and morphology of non-metallic inclusions was modified by Ce, La and Nd, what results a small deformability of non- metallic inclusions during hot-working.

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

    Science.gov (United States)

    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.

  13. Mobility of rare earth element in hydrothermal process and weathering product: a review

    Science.gov (United States)

    Lintjewas, L.; Setiawan, I.

    2018-02-01

    The Rare Earth Element (REE), consists of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Lu, Ho, Er, Tm, Yb, are important elements to be used as raw materials of advanced technology such as semiconductors, magnets, and lasers. The research of REE in Indonesia has not been done. Several researches were conducted on granitic rocks and weathering product such as Bangka, Sibolga, West Kalimantan, West Sulawesi and Papua. REE can be formed by hydrothermal processes such as Bayan Obo, South China. The REE study on active hydrothermal system (geothermal) in this case also has the potential to produce mineral deposits. The purpose of this review paper is to know the mobility of REE on hydrothermal process and weathering products. Mobility of REE in the hydrothermal process can change the distribution patterns and REE content such as Ce, Eu, La, Lu, Nd, Sm, and Y. Another process besides the hydrothermal is weathering process. REE mobility is influenced by weathering products, where the REE will experience residual and secondary enrichment processes in heavier minerals.

  14. Microbial mobilization of rare earth elements (REE from mineral solids—A mini review

    Directory of Open Access Journals (Sweden)

    Fabienne Barmettler

    2016-06-01

    Full Text Available In the light of an expected supply shortage of rare earth elements (REE measures have to be undertaken for an efficient use in all kinds of technical, medical, and agricultural applications as well as—in particular—in REE recycling from post-use goods and waste materials. Biologically- based methods might offer an alternative and supplement to physico-chemical techniques for REE recovery and recycling. A wide variety of physiologically distinct microbial groups have the potential to be applied for REE bioleaching form solid matrices. This source is largely untapped until today. Depending of the type of organism, the technical process (including a series of influencing factors, the solid to be treated, and the target element, leaching efficiencies of 80 to 90% can be achieved. Bioleaching of REEs can help in reducing the supply risk and market dependency. Additionally, the application of bioleaching techniques for the treatment of solid wastes might contribute to the conversion towards a more sustainable and environmental friendly economy.

  15. Ecosystem Composition Controls the Fate of Rare Earth Elements during Incipient Soil Genesis

    Science.gov (United States)

    Zaharescu, Dragos G.; Burghelea, Carmen I.; Dontsova, Katerina; Presler, Jennifer K.; Maier, Raina M.; Huxman, Travis; Domanik, Kenneth J.; Hunt, Edward A.; Amistadi, Mary K.; Gaddis, Emily E.; Palacios-Menendez, Maria A.; Vaquera-Ibarra, Maria O.; Chorover, Jon

    2017-02-01

    The rare earth elements (REE) are increasingly important in a variety of science and economic fields, including (bio)geosciences, paleoecology, astrobiology, and mining. However, REE distribution in early rock-microbe-plant systems has remained elusive. We tested the hypothesis that REE mass-partitioning during incipient weathering of basalt, rhyolite, granite and schist depends on the activity of microbes, vascular plants (Buffalo grass), and arbuscular mycorrhiza. Pore-water element abundances revealed a rapid transition from abiotic to biotic signatures of weathering, the latter associated with smaller aqueous loss and larger plant uptake. Abiotic dissolution was 39% of total denudation in plant-microbes-mycorrhiza treatment. Microbes incremented denudation, particularly in rhyolite, and this resulted in decreased bioavailable solid pools in this rock. Total mobilization (aqueous + uptake) was ten times greater in planted compared to abiotic treatments, REE masses in plant generally exceeding those in water. Larger plants increased bioavailable solid pools, consistent with enhanced soil genesis. Mycorrhiza generally had a positive effect on total mobilization. The main mechanism behind incipient REE weathering was carbonation enhanced by biotic respiration, the denudation patterns being largely dictated by mineralogy. A consistent biotic signature was observed in La:phosphate and mobilization: solid pool ratios, and in the pattern of denudation and uptake.

  16. Thorium. Suppl. Vol. A2

    International Nuclear Information System (INIS)

    Kirby, H.W.; Moebius, S.; Muenzel, H.; Ritcey, G.M.; Molnar, R.; Pouskouleli, G.

    1986-01-01

    The present volume ''Thorium'' Suppl. Vol. A2 of the Gmelin Handbook covers the history of thorium and the preparation of its scientifically and technologically important isotopes, as well as the nuclear properties (including fission properties) of all its isotopes. The thorium isotopes range from 212 Th to 236 Th. The different types of production of all of these isotopes have been described and, in the following chapter, the decay data and fission characteristics. On the other hand, chemical isolation procedures have been outlined only for the more important isotopes 227 Th to 234 Th. Special emphasis, however, was devoted to 232 Th, the only naturally occurring very long-lived isotope. Despite some other applications the specific importance of 232 Th comes from the fact that its neutron capture reaction product 233 U is a fissile nuclide, which makes 232 Th an important isotope in nuclear technology, especially for the so-called ''Thorium High Temperature Reactor'' (THTR). The other longer-lived isotopes are either used in the laboratory for tracer studies (e.g. 234 Th) or for the production of nuclides for isotope batteries (e.g. 230 Th), whereas 233 Th is the nuclide measured for the neutron activation determination of thorium. In the chapters for the isolation and purification of thorium isotopes only those extraction and other separation procedures were mentioned which are relevant to the given process. Detailed information on these topics has been given in specific volumes of this Handbook, e.g. Volume D2 for ''Extraction of Thorium''. The literature is covered to the end of 1984. In some cases, more recent data have been considered. (orig./RB)

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

    Science.gov (United States)

    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

  18. Sources of Extraterrestrial Rare Earth Elements:To the Moon and Beyond

    Science.gov (United States)

    McLeod, C. L.; Krekeler, M. P. S.

    2017-08-01

    The resource budget of Earth is limited. Rare-earth elements (REEs) are used across the world by society on a daily basis yet several of these elements have elements (REE), and Phosphorus (P), (or "KREEP") formed. Today, the KREEP-rich region underlies the Oceanus Procellarum and Imbrium Basin region on the lunar near-side (the Procellarum KREEP Terrain, PKT) and has been tentatively estimated at preserving 2.2 × 10^8 km^3 of KREEP-rich lithologies. The majority of lunar samples (Apollo, Luna, or meteoritic samples) contain REE-bearing minerals as trace phases, e.g., apatite and/or merrillite, with merrillite potentially contributing up to 3% of the PKT. Other lunar REE-bearing lunar phases include monazite, yittrobetafite (up to 94,500 ppm yttrium), and tranquillityite (up to 4.6 wt % yttrium, up to 0.25 wt % neodymium), however, lunar sample REE abundances are low compared to terrestrial ores. At present, there is no geological, mineralogical, or chemical evidence to support REEs being present on the Moon in concentrations that would permit their classification as ores. However, the PKT region has not yet been mapped at high resolution, and certainly has the potential to yield higher REE concentrations at local scales (<10s of kms). Future lunar exploration and mapping efforts may therefore reveal new REE deposits. Beyond the Moon, Mars and other extraterrestrial materials are host to REEs in apatite, chevkinite-perrierite, merrillite, whitlockite, and xenotime. These phases are relatively minor components of the meteorites studied to date, constituting <0.6% of the total sample. Nonetheless, they dominate a samples REE budget with their abundances typically 1-2 orders of magnitude enriched relative to their host rock. As with the Moon, though phases which host REEs have been identified, no extraterrestrial REE resource, or ore, has been identified yet. At present extraterrestrial materials are therefore not suitable REE-mining targets. However, they are host to

  19. Thorium - humic compound interaction in the water of Morro do Ferro (Pocos de Caldas, MG, Brazil)

    International Nuclear Information System (INIS)

    Kuechler, I.L.

    1986-01-01

    Experimental procedures and results are presented on the determination of thorium and organic dissolved carbon (DOC) in natural waters (bore hole and surface waters) from the Morro de Ferro, a thorium - rare earth occurrence situated in the Pocos de Caldas Plateau in Minas Gerais (Brazil). A positive correlation between Th-232 and humic compounds content was abserved. Utilizing ultrafiltration techniques with Amicon membranes (XM-300, PM-10, UM-10 and YM-2), organic compounds with molecular weights above 1000 units were separated and concentrated from waters. Percolation waters rich in organic material concentrate DOC and Th-232 in the high molecular weight fractions ( > 10.000 MW units). Humic acid was separated from a percolation water sample and characterized by elemental and infrared spectroscopic analysis. The distribution coefficient of Th-232 between water and sediment was shown to be inversely correlated to DOC concentration, as reported by other authors for different environments. These results were also confirmed by laboratory experiments, which indicated additionally that low concentrations of humic acid ( [pt

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

    Science.gov (United States)

    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. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Fate and Trophic Transfer of Rare Earth Elements in Temperate Lake Food Webs.

    Science.gov (United States)

    Amyot, Marc; Clayden, Meredith G; MacMillan, Gwyneth A; Perron, Tania; Arscott-Gauvin, Alexandre

    2017-06-06

    Many mining projects targeting rare earth elements (REE) are in development in North America, but the background concentrations and trophic transfer of these elements in natural environments have not been well characterized. We sampled abiotic and food web components in 14 Canadian temperate lakes unaffected by mines to assess the natural ecosystem fate of REE. Individual REE and total REE concentrations (sum of individual element concentrations, ΣREE) were strongly related with each other throughout different components of lake food webs. Dissolved organic carbon and dissolved oxygen in the water column, as well as ΣREE in sediments, were identified as potential drivers of aqueous ΣREE. Log 10 of median bioaccumulation factors ranged from 1.3, 3.7, 4.0, and 4.4 L/kg (wet weight) for fish muscle, zooplankton, predatory invertebrates, and nonpredatory invertebrates, respectively. [ΣREE] in fish, benthic macroinvertebrates, and zooplankton declined as a function of their trophic position, as determined by functional feeding groups and isotopic signatures of nitrogen (δ 15 N), indicating that REE were subject to trophic dilution. Low concentrations of REE in freshwater fish muscle compared to their potential invertebrate prey suggest that fish fillet consumption is unlikely to be a significant source of REE to humans in areas unperturbed by mining activities. However, other fish predators (e.g., piscivorous birds and mammals) may accumulate REE from whole fish as they are more concentrated than muscle. Overall, this study provides key information on the baseline concentrations and trophic patterns for REE in freshwater temperate lakes in Quebec, Canada.

  2. Rare earth elements in freshwater, marine, and terrestrial ecosystems in the eastern Canadian Arctic.

    Science.gov (United States)

    MacMillan, Gwyneth Anne; Chételat, John; Heath, Joel P; Mickpegak, Raymond; Amyot, Marc

    2017-10-18

    Few ecotoxicological studies exist for rare earth elements (REEs), particularly field-based studies on their bioaccumulation and food web dynamics. REE mining has led to significant environmental impacts in several countries (China, Brazil, U.S.), yet little is known about the fate and transport of these contaminants of emerging concern. Northern ecosystems are potentially vulnerable to REE enrichment from prospective mining projects at high latitudes. To understand how REEs behave in remote northern food webs, we measured REE concentrations and carbon and nitrogen stable isotope ratios (∂ 15 N, ∂ 13 C) in biota from marine, freshwater, and terrestrial ecosystems of the eastern Canadian Arctic (N = 339). Wildlife harvesting and tissue sampling was partly conducted by local hunters through a community-based monitoring project. Results show that REEs generally follow a coherent bioaccumulation pattern for sample tissues, with some anomalies for redox-sensitive elements (Ce, Eu). Highest REE concentrations were found at low trophic levels, especially in vegetation and aquatic invertebrates. Terrestrial herbivores, ringed seal, and fish had low total REE levels in muscle tissue (∑REE for 15 elements <0.1 nmol g -1 ), yet accumulation was an order of magnitude higher in liver tissues. Age- and length-dependent REE accumulation also suggest that REE uptake is faster than elimination for some species. Overall, REE bioaccumulation patterns appear to be species- and tissue-specific, with limited potential for biomagnification. This study provides novel data on the behaviour of REEs in ecosystems and will be useful for environmental impact assessment of REE enrichment in northern regions.

  3. Fractionation of rare earth elements in the Mississippi River estuary and river sediments

    Science.gov (United States)

    Adebayo, S. B.; Johannesson, K. H.

    2017-12-01

    This study presents the first set of data on the fractionation of rare earth elements (REE) in the mixing zone between the Mississippi River and the Gulf of Mexico, as well as the fractionation of REE in the operationally defined fractions of Mississippi River sediments. This subject is particularly important because the Mississippi river is one of the world's major rivers, and contributes a substantial amount of water and sediment to the ocean. Hence, it is a major source of trace elements to the oceans. The geochemistry of the REE in natural systems is principally important because of their unique chemical properties, which prompt their application as tracers of mass transportation in modern and paleo-ocean environments. Another important consideration is the growth in the demand and utilization of REE in the green energy and technology industries, which has the potential to bring about a change in the background levels of these trace elements in the environment. The results of this study show a heavy REE enrichment of both the Mississippi River water and the more saline waters of the mixing zone. Our data demonstrate that coagulation and removal of REE in the low salinity region of the estuary is more pronounced among the Light REE ( 35% for Nd) compared to the Heavy REE. Remarkably, our data also indicate that REE removal in the Mississippi River estuary is significantly less than that observed in other estuaries, including the Amazon River system. We propose that the high pH/alkalinity of the Mississippi River is responsible for the greater stability of REE in the Mississippi River estuary. The results of sequential extraction of river sediments reveal different Sm/Nd ratios for the various fractions, which we submit implies different 143Nd/144Nd ratios of the labile fractions of the sediments. The possible impact of such hypothesized different Nd isotope signatures of labile fractions of the river sediments on Gulf of Mexico seawater is under investigation.

  4. Drying characteristics of thorium fuel corrosion products

    Science.gov (United States)

    Smith, R.-E. Lords

    2004-07-01

    The open literature and accessible US Department of Energy-sponsored reports were reviewed for the dehydration and rehydration characteristics of potential corrosion products from thorium metal and thorium oxide nuclear fuels. Mixed oxides were not specifically examined unless data were given for performance of mixed thorium-uranium fuels. Thorium metal generally corrodes to thorium oxide. Physisorbed water is readily removed by heating to approximately 200 °C. Complete removal of chemisorbed water requires heating above 1000 °C. Thorium oxide adsorbs water well in excess of the amount needed to cover the oxide surface by chemisorption. The adsorption of water appears to be a surface phenomenon; it does not lead to bulk conversion of the solid oxide to the hydroxide. Adsorptive capacity depends on both the specific surface area and the porosity of the thorium oxide. Heat treatment by calcination or sintering reduces the adsorption capacity substantially from the thorium oxide produced by metal corrosion.

  5. Thorium Energy for the World

    CERN Document Server

    Revol, Jean-Pierre; Bourquin, Maurice; Kadi, Yacine; Lillestol, Egil; De Mestral, Jean-Christophe; Samec, Karel

    2016-01-01

    The Thorium Energy Conference (ThEC13) gathered some of the world’s leading experts on thorium technologies to review the possibility of destroying nuclear waste in the short term, and replacing the uranium fuel cycle in nuclear systems with the thorium fuel cycle in the long term. The latter would provide abundant, reliable and safe energy with no CO2 production, no air pollution, and minimal waste production. The participants, representatives of 30 countries, included Carlo Rubbia, Nobel Prize Laureate in physics and inventor of the Energy Amplifier; Jack Steinberger, Nobel Prize Laureate in physics; Hans Blix, former Director General of the International Atomic Energy Agency (IAEA); Rolf Heuer, Director General of CERN; Pascal Couchepin, former President of the Swiss Confederation; and Claude Haegi, President of the FEDRE, to name just a few. The ThEC13 proceedings are a source of reference on the use of thorium for energy generation. They offer detailed technical reviews of the status of thorium energy ...

  6. Study of the oxides nature effect of rare and rare earth elements on the aluminium-chromium catalyst properties

    International Nuclear Information System (INIS)

    Dadashev, B.A.; Abbasov, S.G.; Sarydzhanov, A.A.; AN Azerbajdzhanskoj SSR, Baku. Inst. Neftekhimicheskikh Protsessov)

    1975-01-01

    Adsorption studies have shown that oxides of rare and rare earth elements REE appreciably influence the structure of aluminium-chrome catalyst. Alkaline promotors, unlike REE, contribute to the formation of developed contact surface. Electrophysical investigations show that oxides of rare elements introduced into the catalyst increase its conductivity and activation energy. As for REE oxides, they decrease the conductivity and increase the activation energy. Catalysts with developed surface and high conductivity are also more active in the reaction of isopentane dehydration

  7. Geochemistry of rare earth elements in the mainstream of the Yangtze River, China

    International Nuclear Information System (INIS)

    Li, X.; Zhang, S.; Wang, L.; Zhang, C.

    1998-01-01

    Water, suspended matter, and sediment samples were taken from 8 locations along the Yangtze River in 1992. The concentration and speciation (exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter, and residual forms) of rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) were determined by instrumental neutron activation analysis (INAA).The contents of the soluble fraction of REEs in the river are low, and REEs mainly reside in particulate form. In the particles, the chondrite-normalized distribution patterns show significant LREE enrichment and Eu-depletion. While normalized to shales, both sediments and suspended matter samples show relative LREE enrichment and HREE depletion. REEs are relatively enriched in fine-grained fractions of the sediments.exchangeable. About 65 to 85% of REEs in the particles exist in the residual form, and the exchangeable form is very low. High proportions of residual REEs reveal that REEs in sediments and suspended matter are controlled by their abundances in the earth's crust. Carbonate, Fe-Mn oxide and organic fractions of REEs in sediments account for 2.4-6.9%, 5.2-11.1%, and 7.3-14.0% of the total contents respectively. They are similar to those in the suspended matter. This shows that carbonates, Fe-Mn oxides and organic matter play important roles during the particle-water interaction processes. By normalization to shales, the 3 forms of REEs follow convex shapes according to atomic number with middle REE (Sm, Eu, and Tb) enrichment, while light REE and heavy REE are depleted. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  8. Fabrication of thorium nitrate at the factory at the Bouchet

    International Nuclear Information System (INIS)

    Braun, C.; Lorrain, Ch.; Mahut, R.; Mariette, R.; Muller, J.; Prugnard, J.

    1958-01-01

    A urano-thorianite mineral from Madagascar is industrially treated at the factory of the Bouchet in order to obtain pure thorium in the form of the nitrate and a uranium concentrate in the form of uranate. The required factory was designed and constructed in 1955 and 1956 by the firm Potasse et Engrais Chimiques (P.E.C.) on behalf of the French Atomic Energy authority. The mineral which has previously undergone a gravimetric sorting and enrichment at the mine, is in the form of a heavy rock (the density can be as high as 10), having a cubic structure. It consists principally of a mixture of thorium oxide and uranium oxide and contains between 50 and 75 per cent thorium and between 5 and 20 per cent of uranium. On the same sample a high content in either thorium or uranium in general corresponds to a low content in the other of the two metals; this rule is not however always obeyed absolutely. Among other elements present we shall only mention the Pb, Fe, Ce, Ra and other radioactive elements, since their presence influences the treatment of the mineral. We shall first briefly describe the process, which has already been described in previous publications, we consider to be worthy of attention. (author) [fr

  9. Determination of rare earth elements concentration at different depth profile of Precambrian pegmatites using instrumental neutron activation analysis.

    Science.gov (United States)

    Sadiq Aliyu, Abubakar; Musa, Yahaya; Liman, M S; Abba, Habu T; Chaanda, Mohammed S; Ngene, Nnamani C; Garba, N N

    2018-01-01

    The Keffi area hosts abundant pegmatite bodies as a result of the surrounding granitic intrusions. Keffi is part of areas that are geologically classified as North Central Basement Complex. Data on the mineralogy and mineralogical zonation of the Keffi pegmatite are scanty. Hence the need to understand the geology and mineralogical zonation of Keffi pegmatites especially at different depth profiles is relevant as a study of the elemental composition of the pegmatite is essential for the estimation of its economic viability. Here, the relative standardization method of instrumental neutron activation analysis (INAA) has been used to investigate the vertical deviations of the elemental concentrations of rare earth elements (REEs) at different depth profile of Keffi pegmatite. This study adopted the following metrics in investigating the vertical variations of REEs concentrations. Namely, the total contents of rare earth elements (∑REE); ratio of light to heavy rare earth elements (LREE/HREE), which defines the enrichment or depletion of REEs; europium anomaly (Eu/Sm); La/Lu ratio relative to chondritic meteorites. The study showed no significant variations in the total content of rare elements between the vertical depth profiles (100-250m). However, higher total concentrations of REEs (~ 92.65ppm) were recorded at the upper depth of the pegmatite and the europium anomaly was consistently negative at all the depth profiles suggesting that the Keffi pegmatite is enriched with light REEs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Advanced thorium cycles in LWRs and HWRs

    International Nuclear Information System (INIS)

    Radkowsky, A.

    The main aspects of advanced thorium cycles in LWRs and HWRs are reviewed. New concepts include the seed blanket close packed heavy water breeder, the light water seed blanket thorium burner and self-induced thorium cycle in CANDU type reactors. (author)

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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) 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 is probably best explained by preferential alteration of feldspars and/or accessory mineral phases

  13. Rare Earth Elements used as fingerprints of differentiated sediment sources in the Ria de Aveiro (Portugal

    Directory of Open Access Journals (Sweden)

    Maria Virgínia Alves Martins

    2016-02-01

    Full Text Available This work focuses on the distribution and the controlling factors of rare earth element (REE total concentrations and fractionation patterns in fine sediment fractions of 53 samples collected along the main channels of the Ria de Aveiro, a northern Portuguese coastal lagoon. Total and available concentrations and residual phases of REE and total concentrations in three chemically partitioned fractions (S1 - adsorbed by clay and co-precipitated with carbonates; S2 - adsorbed by organic matter; S3 - adsorbed by amorphous Mn hydroxides are analysed. These data are joinly analysed with physicochemical, textural and mineralogical and other geochemical data. Sediment samples mainly consisted of phyllosilicates, quartz, plagioclase and K–feldspars. Cerium (Ce is the most abundant REE in the residual phase and displays the lowest total available percentage, whereas Yttrium (Y is the most available. The highest total concentration and residual concentration (R of Ce, Lanthanum (La, Scandium (Sc and Y are mostly related to fine grained sediments, suggesting that their distributions are conditioned by lagoon hydrodynamics. The dissimilar distribution of REE-S1, REE-S2 and REE-S3 indicates differentiated sedimentary processes. The enrichment of REE-S2 and REE-S3 is related essentially to biogeochemical processes inside the lagoon. The REE-S1, as well as Ce-S1/Sc-R, trace sediments supplied from the northern areas suplyed mostly by the Douro River outflow and from the Antuã River. In the past, the sediments suplyed by the Douro River through the litoral drift contributed to the formation of the lagoon islands. Thus the relatatively high Ce-S1/Sc-R values inside the lagoon allowed the identification of: sediments supplied from the litoral drift and deposited near the lagoon mouth, erosional processes of the lagoonal islands and sediments supplied by the Antuã River. This work demonstrates that the available concentrations of rare earth elements can be

  14. Aqueous Rare Earth Element Patterns and Concentration in Thermal Brines Associated With Oil and Gas Production

    Energy Technology Data Exchange (ETDEWEB)

    Nye, Charles [University of Wyoming; Quillinan, Scott Austin [University of Wyoming; Neupane, Ghanashyam [Idaho National Lab. (INL), Idaho Falls, ID (United States); McLing, Travis [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-02-13

    This study is part of a joint effort by the University of Wyoming (UW) School of Energy Resources (SER), the UW Engineering Department, Idaho National Laboratories (INL), and the United States Geological Survey (USGS) to describe rare earth element concentrations in oil and gas produced waters and in coal-fired power station ash ponds. In this work we present rare earth element (REE) and trace metal behavior in produced water from four Wyoming oil and gas fields and surface ash pond water from two coal-fired power stations. The concentration of REEs in oil and gas produced waters is largely unknown. For example, of the 150,000 entries in the USGS National Produced Waters Geochemical Database less than 5 include data for REEs. Part of the reason for this scarcity is the analytical challenge of measuring REEs in high salinity, hydrocarbon-bearing waters. The industry standard for water analysis struggles to detect REEs in natural waters under ideal conditions. The detection of REEs in oil and gas field samples becomes all but impossible with the background noise and interferences caused by high concentrations of non-REE ions and residual hydrocarbons. The INL team members have overcome many of these challenges (e.g. McLing, 2014), and continue to develop their methods. Using the methods of the INL team members we measured REEs in high salinity oil and gas produced waters. Our results show that REEs exist as a dissolved species in all waters measured for this project, typically within the parts per trillion range. The samples may be grouped into two broad categories analytically, and these categories match their genesis: Wyoming oil and gas brines contain elevated levels of Europium, and Wyoming industrial pond waters show elevation in heavy REEs (HREEs). While broadly true, important variations exist within both groups. In the same field Europium can vary by more than an order of magnitude, and likewise HREEs in industrial ponds at the same site can vary by more than

  15. Extractive spectrophotometric determination of thorium

    International Nuclear Information System (INIS)

    Venkatesan, M.; Gopalakrishnan, V.; Ramanujam, A.; Nadkarni, M.N.

    1981-01-01

    An extractive spectrophotometric method has been standardized for the analysis of 0.2 to 1.6 milligrams of thorium present in nitric acid solutions. The method involves the extraction of thorium from nitric acid solutions into 0.5 M thenoyl trifluoro acetone (HTTA) in benzene and its direct estimation from the organic extract by spectrophotometry as Thoron colour complex. In this method, interference due to iron upto 5 milligrams can be suppressed by adding ascorbic acid in the ratio of 1:2 prior to HTTA extraction. Uranium(VI) does not interefere even when present in 2000 times the amount of thorium. Plutonium and cerium do not interfere at one milligram level whereas zirconium interferes in this method. The overall error variation and precision of this method has been determined to be +- 3.5%. (author)

  16. [Effects of arbuscular mycorrhizal fungi on the growth and rare earth elements uptake of soybean grown in rare earth mine tailings].

    Science.gov (United States)

    Guo, Wei; Zhao, Ren-xin; Zhao, Wen-jing; Fu, Rui-ying; Guo, Jiang-yuan; Zhang, Jun

    2013-05-01

    A greenhouse pot experiment was conducted to investigate the influence of arbuscular mycorrhizal (AM) fungi Glomus versiforme on the plant growth, nutrient uptake, C: N: P stoichiometric, uptake of heavy metals and rare earth elements by soybean (Glycine max) grown in rare earth mine tailings. The aim was to provide a basis for the revegetation of rare earth mine tailings. The results indicated that soybean had a high mycorrhizal colonization and symbiotic associations were successfully established with G. versiforme, with an average rate of approximately 67%. The colonization of G. versiforme significantly promoted the growth of soybean, increased P, K contents, and decreased C: N: P ratios, supporting the growth rate hypothesis. Inoculation with G. versiforme significantly decreased shoots and roots La, Ce, Pr and Nd concentrations of soybean compared to the control treatment. However, inoculation with G. versiforme had no significant effect on the heavy metal concentrations, except for significantly decreased shoot Fe and Cr concentrations and increased root Cd concentrations. The experiment demonstrates that AM fungi have a potential role for soybean to adapt the composite adversity of rare earth tailings and play a positive role in revegetation of rare earth mine tailings. Further studies on the role of AM fungi under natural conditions should be conducted.

  17. Rare earth element exchange through the Bosporus : The Black Sea as a net source of REEs to the Mediterranean Sea

    NARCIS (Netherlands)

    Schijf, Johan; Baar, Hein J.W. de; German, C.R.

    1995-01-01

    The Bosporus is the only source of seawater to the Black Sea and helps to maintain the basin-wide salinity gradient that caused the Black Sea to become the largest permanently anoxic basin in the world, some 3000 years ago. Concentrations of dissolved rare earth elements (REEs) in each of the three

  18. Signatures of rare-earth elements in banded corals of Kalpeni atoll-Lakshadweep archipelago in response to monsoonal variations

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.A.S.; Nath, B.N.; Balaram, V.

    Concentrations of rare-earth elements (REE) have been determined in seasonal bands of Porites species collected from the Lakshadweep lagoon. Total REE (REE) are very low (less than 3 ppm) in these corals. Seasonal variations in REE appear to have...

  19. Vertical distributions and speciation of dissolved rare earth elements in the anoxic brines of Bannock Basin, eastern Mediterranean Sea

    NARCIS (Netherlands)

    Schijf, Johan; Baar, Hein J.W. de; Millero, Frank J.; Byrne, R.H.

    1995-01-01

    Vertical distributions of dissolved rare earth elements (REEs) are presented for the anoxic, highly sulfidic brines of Bannock Basin in the eastern Mediterranean Sea. REE concentrations at the seawater-brine interface are the highest ever recorded in the water column of an anoxic basin and

  20. Life cycle assessment of the production of rare earth elements for energy applications: a review

    Directory of Open Access Journals (Sweden)

    Julio eNavarro

    2014-11-01

    Full Text Available Rare earth elements (REEs are a group of seventeen elements with similar chemical properties, including fifteen in the lanthanide group, yttrium, and scandium. Due to their unique physical and chemical properties REEs gain increasing importance in many new energy technologies and systems that contribute to reduce greenhouse gas emissions and fossil fuel depletion (e.g., wind turbine, electric vehicles, high efficiency lighting, batteries, and hydrogen storage. However, it is well known that production of REEs is far from environmentally sustainable as it requires significant material and energy consumption while generating large amounts of air/water emissions and solid waste. Although life cycle assessment (LCA has been accepted as the most comprehensive approach to quantify the environmental sustainability of a product or process, to date, there have been only very limited LCA studies on the production of REEs. With the continual growth of renewable energy and energy efficient technologies, global production of REEs will increase. Therefore reducing environmental footprints of REE production becomes critical and identifying environmental hotspots based on a holistic and comprehensive assessment on environmental impacts serves as an important starting point. After providing an overview of LCA methodology and a high-level description of the major REE production routes used from 1990s to today, this paper reviews the published LCA studies on the production of REEs. To date, almost all the LCA studies are based on process information collected from the operation of Mountain Pass facility in U.S. in 1990s and the operation of facilities in Bayan Obo, China. Knowledge gaps are identified and future research efforts are suggested to advance understanding on environmental impacts of REE production from the life cycle perspective.

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Leaching of rare earth elements from fluorescent powder using the tea fungus Kombucha.

    Science.gov (United States)

    Hopfe, Stefanie; Flemming, Katrin; Lehmann, Falk; Möckel, Robert; Kutschke, Sabine; Pollmann, Katrin

    2017-04-01

    In most modern technologies such as flat screens, highly effective magnets and lasers, as well as luminescence phosphors, Rare Earth Elements (REE) are used. Unfortunately no environmentally friendly recycling process exists so far. In comparison to other elements the interaction of microorganisms with REE has been studied to a less extent. However, as REE are ubiquitously present in nature it can be assumed that microorganisms play an important role in the biogeochemistry of REE. This study investigates the potential of organic acid-producing microbes for extracting REE from industrial waste. In Germany, 175 tons of fluorescent phosphor (FP) are collected per year as a distinct fraction from the recycling of compact fluorescent lamps. Because the FP contains about 10% of REE-oxides bound in the so-called triband dyes it is a readily accessible secondary resource of REE. Using the symbiotic mixed culture Kombucha, consisting of yeasts and acetic acid bacteria, REE were leached at a significant rate. The highest leaching-rates were observed in shake cultures using the entire Kombucha-consortium or its supernatant as leaching agent compared to experiments using the isolates Zygosaccharomyces lentus and Komagataeibacter hansenii as leaching organisms. During the cultivation, the pH decreased as a result of organic acid production (mainly acetic and gluconic acid). Thus, the underlying mechanism of the triband dye solubilisation is probably linked to the carboxyl-functionality or a proton excess. In accordance with the higher solubility of REE-oxides compared to REE-phosphates and -aluminates, the red dye Y 2 O 3 :Eu 2+ containing relatively expensive REE was shown to be preferentially solubilized. These results show that it is possible to dissolve the REE-compounds of FP with the help of microbial processes. Moreover, they provide the basis for the development of an eco-friendly alternative to the currently applied methods that use strong inorganic acids or toxic

  3. Ultrasound-assisted extraction of rare-earth elements from carbonatite rocks.

    Science.gov (United States)

    Diehl, Lisarb O; Gatiboni, Thais L; Mello, Paola A; Muller, Edson I; Duarte, Fabio A; Flores, Erico M M

    2018-01-01

    In view of the increasing demand for rare-earth elements (REE) in many areas of high technology, alternative methods for the extraction of these elements have been developed. In this work, a process based on the use of ultrasound for the extraction of REE from carbonatite (an igneous rock) is proposed to avoid the use of concentrated reagents, high temperature and excessive extraction time. In this pioneer work for REE extraction from carbonatite rocks in a preliminary investigation, ultrasonic baths, cup horn systems or ultrasound probes operating at different frequencies and power were evaluated. In addition, the power released to the extraction medium and the ultrasound amplitude were also investigated and the temperature and carbonatite mass/volume of extraction solution ratio were optimized to 70°C and 20mg/mL, respectively. Better extraction efficiencies (82%) were obtained employing an ultrasound probe operating at 20kHz for 15min, ultrasound amplitude of 40% (692Wdm -3 ) and using a diluted extraction solution (3% v/v HNO 3 +2% v/v HCl). It is important to mention that high extraction efficiency was obtained even using a diluted acid mixture and relatively low temperature in comparison to conventional extraction methods for REE. A comparison of results with those obtained by mechanical stirring (500rpm) using the same conditions (time, temperature and extraction solution) was carried out, showing that the use of ultrasound increased the extraction efficiency up to 35%. Therefore, the proposed ultrasound-assisted procedure can be considered as a suitable alternative for high efficiency extraction of REE from carbonatite rocks. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2016-06-07

    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.

  5. Novel Extraction Process Of Rare Earth Elements From NdFeB Powders Via Alkaline Treatment

    Directory of Open Access Journals (Sweden)

    Chung K.W.

    2015-06-01

    Full Text Available The alkaline treatment of NdFeB powders in NaOH solution at various equivalent amounts of NaOH at 100°C was performed. The resultant powders were then leached in 0.5M H2SO4 solution at 25°C for 2 minutes. At 5 equivalents of NaOH, neodymium in NdFeB powders was partially transformed to neodymium hydroxide. The transformation of neodymium to neodymium hydroxide actually occurred at 10 equivalents of NaOH and was facilitated by increasing the equivalent of NaOH from 10 to 30. In addition, iron was partially transformed to magnetite during the alkaline treatment, which was also promoted at a higher equivalent of NaOH. The leaching yield of neodymium from alkaline-treated powders was increased with an increasing equivalent of NaOH up to 10; however, it slightly decreased with the equivalent NaOH of over 10. The leaching yield of iron was inversely proportional to that of rare earth elements. NdFeB powders treated at 10 equivalents of NaOH showed a maximum leaching yield of neodymium and dysprosium of 91.6% and 94.6%, respectively, and the lowest leaching yield of iron of 24.2%, resulting in the highest selective leaching efficiency of 69.4%.

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

    Science.gov (United States)

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

    2015-08-18

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

  7. Photoelectric characteristics of rare earth element Eu-doped MoS2 thin films

    Science.gov (United States)

    Shi, Weilin; Li, Zhichao; Wang, Lin; Wu, Shuyan; Zhang, Gaoning; Meng, Miaofei; Ma, Xiying

    2018-01-01

    We present the influences of rare earth element Eu3+ doping on the photoelectric characteristics of molybdenum disulfide (MoS2) films deposited on p-Si substrates using vapor deposition method. The surface topography, crystalline structure, light absorption, and luminescence properties of Eu3+ doped and undoped MoS2 thin films were investigated in detail. We found that the Eu3+ doped MoS2 films have better crystallinity, and their electron mobility and conductivity are approximately one order of magnitude higher than those of the undoped films. In addition, we observed that the light absorption and photoluminescence intensities of the doped films in the visible light range, they were enhanced by approximately two orders of magnitude than those of the undoped MoS2 films at room temperature. Moreover, we found that the photoelectric response characteristics of the doped MoS2 / Si heterojunction improved significantly. The results show that the Eu3+ doped MoS2 films can be used to fabricate high efficiency luminescent and optoelectronic devices.

  8. Marine phosphorites as potential resources for heavy rare earth elements and yttrium

    Science.gov (United States)

    Hein, James; Koschinsky, Andrea; Mikesell, Mariah; Mizell, Kira; Glenn, Craig R.; Wood, Ray

    2016-01-01

    Marine phosphorites are known to concentrate rare earth elements and yttrium (REY) during early diagenetic formation. Much of the REY data available are decades old and incomplete, and there has not been a systematic study of REY distributions in marine phosphorite deposits that formed over a range of oceanic environments. Consequently, we initiated this study to determine if marine phosphorite deposits found in the global ocean host REY concentrations of high enough grade to be of economic interest. This paper addresses continental-margin (CM) and open-ocean seamount phosphorites. All 75 samples analyzed are composed predominantly of carbonate fluorapatite and minor detrital and authigenic minerals. CM phosphorites have low total REY contents (mean 161 ppm) and high heavy REY (HREY) complements (mean 49%), while seamount phosphorites have 4–6 times higher individual REY contents (except for Ce, which is subequal; mean ΣREY 727 ppm), and very high HREY complements (mean 60%). The predominant causes of higher concentrations and larger HREY complements in seamount phosphorites compared to CM phosphorites are age, changes in seawater REY concentrations over time, water depth of formation, changes in pH and complexing ligands, and differences in organic carbon content in the depositional environments. Potential ore deposits with high HREY complements, like the marine phosphorites analyzed here, could help supply the HREY needed for high-tech and green-tech applications without creating an oversupply of the LREY.

  9. Spatial and temporal analysis of rare earth elements in the Neuse River, North Carolina

    Science.gov (United States)

    Smith, C. D.; Liu, X. M.

    2016-12-01

    Rare earth elements (REEs) found in bottom sediment and dissolved river load samples serve as excellent monitors of continental weathering processes within a basin. However, the extent of REE variation along a river's profile is poorly understood due to the influences several physical and chemical parameters have upon shale-normalized (i.e., PAAS) REE concentrations. In this investigation, we report on analyses of REE concentrations of bulk bed sediment and dissolved river load samples to better understand the transport of river-born REE collected at 5 sampling stations along the Neuse River, North Carolina. The gauge height, pH, turbidity, dissolved oxygen, nitrate concentration and water temperature are recorded at each sampling location. The underlying geology is also noted. These factors collectively influence REE weathering. PAAS-normalized REE patterns of dissolved water loads vary spatially among the 5 different sampling stations and exhibit station-station temporal variation as well as overall river variation. Our results show that REE patterns in dissolved river loads are similar across the length of the river with the exception of gadolinium (Gd) spikes. Further work is necessary to determine the nature of these spikes and their possible sources. These findings may indicate that the overall influence of underlying basin rock does not significantly alter REE patterns along the profile of a river, but rather suggest that a homogenized pattern occurs as a result of mixing.

  10. Marine Phosphorites as Potential Resources for Heavy Rare Earth Elements and Yttrium

    Directory of Open Access Journals (Sweden)

    James R. Hein

    2016-08-01

    Full Text Available Marine phosphorites are known to concentrate rare earth elements and yttrium (REY during early diagenetic formation. Much of the REY data available are decades old and incomplete, and there has not been a systematic study of REY distributions in marine phosphorite deposits that formed over a range of oceanic environments. Consequently, we initiated this study to determine if marine phosphorite deposits found in the global ocean host REY concentrations of high enough grade to be of economic interest. This paper addresses continental-margin (CM and open-ocean seamount phosphorites. All 75 samples analyzed are composed predominantly of carbonate fluorapatite and minor detrital and authigenic minerals. CM phosphorites have low total REY contents (mean 161 ppm and high heavy REY (HREY complements (mean 49%, while seamount phosphorites have 4–6 times higher individual REY contents (except for Ce, which is subequal; mean ΣREY 727 ppm, and very high HREY complements (mean 60%. The predominant causes of higher concentrations and larger HREY complements in seamount phosphorites compared to CM phosphorites are age, changes in seawater REY concentrations over time, water depth of formation, changes in pH and complexing ligands, and differences in organic carbon content in the depositional environments. Potential ore deposits with high HREY complements, like the marine phosphorites analyzed here, could help supply the HREY needed for high-tech and green-tech applications without creating an oversupply of the LREY.

  11. Distribution and source of rare earth elements in PM2.5in Xiamen, China.

    Science.gov (United States)

    Wang, Shanshan; Yu, Ruilian; Hu, Gongren; Hu, Qichao; Zheng, Quan

    2017-12-01

    Particulate matter with diameter ≤2.5 µm (PM 2.5 ) is a serious atmospheric pollutant. Composition and source analyses are essential for controlling PM 2.5 . Rare earth elements (REEs) have received little attention as a component of PM 2.5 . In the present study, PM 2.5 samples were collected in urban and suburban areas in Xiamen and analyzed for REEs. The concentration range of total REEs (∑REE) is 12.07 to 98.45 mg/kg, with a mean of 38.53 mg/kg, in urban PM 2.5 and 16.44 to 160.62 mg/kg, with a mean of 42.94 mg/kg, in suburban PM 2.5 . Light REE concentrations are higher in suburban PM 2.5 , whereas heavy REE concentrations are higher in urban PM 2.5 , implying distinct sources of REEs in urban and suburban PM 2.5 . The scatter plots of δEu-∑REE and La-Ce-Sm suggest that REEs in urban PM 2.5 originate from gasoline- and diesel-vehicle exhaust, whereas those in suburban PM 2.5 are mainly influenced by gasoline-vehicle exhaust. Environ Toxicol Chem 2017;36:3217-3222. © 2017 SETAC. © 2017 SETAC.

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

    Science.gov (United States)

    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. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Fractionation in the solar nebula - Condensation of yttrium and the rare earth elements

    Science.gov (United States)

    Boynton, W. V.

    1975-01-01

    The condensation of Y and the rare earth elements (REE) from the solar nebula may be controlled by thermodynamic equilibrium between gas and condensed solids. Highly fractionated REE patterns may result if condensates are removed from the gas before condensation is complete. It is found that the fractionation is not a smooth function of REE ionic radius but varies in an extremely irregular pattern. Both Yb and Eu are predicted to be extremely depleted in the early condensate without the requirement of condensation in the divalent state. The model is discussed with respect to a highly fractionated pattern observed by Tanaka and Masuda (1973), in a pink Ca-Al-rich inclusion from the Allende meteorite and can account for the abundances of each REE determined. According to the model this inclusion represents a condensate from a previously fractionated gas rather than from a gas of solar composition. Before the condensation of this inclusion, an earlier condensate was formed and was removed from equilibrium with the gas.

  14. Rare earth elements in sedimentary phosphate deposits: Solution to the global REE crisis?

    Science.gov (United States)

    Emsbo, Poul; McLaughlin, Patrick I.; Breit, George N.; du Bray, Edward A.; Koenig, Alan E.

    2015-01-01

    The critical role of rare earth elements (REEs), particularly heavy REEs (HREEs), in high-tech industries has created a surge in demand that is quickly outstripping known global supply and has triggered a worldwide scramble to discover new sources. The chemical analysis of 23 sedimentary phosphate deposits (phosphorites) in the United States demonstrates that they are significantly enriched in REEs. Leaching experiments using dilute H2SO4 and HCl, extracted nearly 100% of their total REE content and show that the extraction of REEs from phosphorites is not subject to the many technological and environmental challenges that vex the exploitation of many identified REE deposits. Our data suggest that phosphate rock currently mined in the United States has the potential to produce a significant proportion of the world's REE demand as a byproduct. Importantly, the size and concentration of HREEs in some unmined phosphorites dwarf the world's richest REE deposits. Secular variation in phosphate REE contents identifies geologic time periods favorable for the formation of currently unrecognized high-REE phosphates. The extraordinary endowment, combined with the ease of REE extraction, indicates that such phosphorites might be considered as a primary source of REEs with the potential to resolve the global REE (particularly for HREE) supply shortage.

  15. Behavioral deficits and neural damage of Caenorhabditis elegans induced by three rare earth elements.

    Science.gov (United States)

    Xu, Tiantian; Zhang, Manke; Hu, Jiani; Li, Zihan; Wu, Taipu; Bao, Jianing; Wu, Siyu; Lei, Lili; He, Defu

    2017-08-01

    Rare earth elements (REEs) are widely used in industry, agriculture, medicine and daily life in recent years. However, environmental and health risks of REEs are still poorly understood. In this study, neurotoxicity of trichloride neodymium, praseodymium and scandium were evaluated using nematode Caenorhabditis elegans as the assay system. Median lethal concentrations (48 h) were 99.9, 157.2 and 106.4 mg/L for NdCl 3 , PrCl 3 and ScCl 3 , respectively. Sublethal dose (10-30 mg/L) of these trichloride salts significantly inhibited body length of nematodes. Three REEs resulted in significant declines in locomotor frequency of body bending, head thrashing and pharyngeal pumping. In addition, mean speed and wavelength of crawling movement were significantly reduced after chronic exposure. Using transgenic nematodes, we found NdCl 3 , PrCl 3 and ScCl 3 resulted in loss of dendrite and soma of neurons, and induced down-expression of dat-1::GFP and unc-47::GFP. It indicates that REEs can lead to damage of dopaminergic and GABAergic neurons. Our data suggest that exposure to REEs may cause neurotoxicity of inducing behavioral deficits and neural damage. These findings provide useful information for understanding health risk of REE materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Geochemical characteristics of rare earth elements in the surface sediments from the Spratly Islands of China.

    Science.gov (United States)

    Li, Jingxi; Sun, Chengjun; Zheng, Li; Yin, Xiaofei; Chen, Junhui; Jiang, Fenghua

    2017-01-30

    The geochemistry of rare earth elements (REE) in surface sediment from Cuarteron reef (N1), Johnson reef (N2), Hugh reef (N3), Gaven reef (N4), Fiery cross reef (N5), and Subi reef (N6) were firstly studied. The total REE abundance (∑REE) varied from 2.244μg·g -1 to 21.661μg·g -1 , with an average of 4.667μg·g -1 . The LREE/HREE was from 2.747 to 9.869, with an average of 3.687, which indicated that the light REE was evidently enriched. Fractionation was observed between LREE and HREE. Gd with a negative anomaly was also detected in all of the stations. The negative anomalies of δEu from 0.11 to 0.25, with an average of 0.22, and the positive anomalies of δCe from 1.38 to 3.86, with an average of 1.63. The REE individual correlation values with Ca, Mn, Mg, Sr were r Ca =-0.05, r Mn =0.26, r Mg =-0.14, and r Sr =0.08. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2015-01-01

    In this work, the geochemistry of the rare earth elements (REE) was studied 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.

  18. In-situ measurements of rare earth elements in deep sea sediments using nuclear methods.

    Science.gov (United States)

    Obhođaš, Jasmina; Sudac, Davorin; Meric, Ilker; Pettersen, Helge E S; Uroić, Milivoj; Nađ, Karlo; Valković, Vlado

    2018-03-21

    The prospecting activities for finding new rare earth elements (REE) sources have increased greatly in recent years. One of the main discoveries was announced in 2011 by Japanese researchers who found large quantities of REE on the ocean seafloor at the sea depths greater than 4,000 m. The classic approach to investigate REE in deep sea sediments is to obtain sediment samples by drilling that is followed by laborious laboratory analysis. This is very expensive, time consuming and not appropriate for exploring vast areas. In order to efficiently explore the ocean floor for REE deposits, the further development of affordable sensors is needed. Here, we propose two nuclear techniques for exploring REE in surface deep sea sediments: i) Passive measurement of lutetium-176 radioactivity, appropriate if long-term in-situ measurements are possible, and ii) The use of the neutron sensor attached to a remotely operated vehicle for rapid in-situ measurement of gadolinium by thermal neutron-capture. Since concentrations of lutetium and gadolinium show strong linear correlation to the total REE concentrations in deep sea sediments, it is possible to deduce the total REE content by measuring Lu or Gd concentrations only.

  19. Environmental geochemistry of rare earth elements in a typical landscape in REE mining area, Southern Jiangxi

    International Nuclear Information System (INIS)

    Gao Xiaojiang; Zhang Shen; Wang Lijun; Liu Shujuan; Wang Yuqi; Chen Hongmin

    1997-01-01

    The content, distribution and speciation of rare earth elements (REEs) in a typical geochemical landscape in a sub-tropical zone, Southern Jiangxi, have been studied systemically. Results showed that contents of REEs in various landscape unit are different, the distribution of REEs is controlled by the characteristics of parent rock and influenced by superficial actions. The contents of REEs in hydromorphic landscape are obviously higher than those in eluvial landscape and accumulative leaching landscape, and there is a vertically fractional phenomenon of REEs in the profile of eluvial landscape. The REE- normalized patterns of distribution in geochemical landscape are similar to that in parent rock, with strong Eu-depletion. However, the differentiation between light REEs and heavy REEs, and the Ce anomaly have been observed. Study on speciation of REEs in each landscape unit showed that REEs are mainly exist in exchangeable formin eluvial and accumulative leaching landscape, but Ce is anomaly; in hydromorphic landscape the main form of REEs is bond to organic matter, especially loosely bound to organic matter. In short, the proportion of non-stable REEs is much higher, over 80%, so REEs are very active, and efficient to plants in the landscape. Finally, the biological effect and influence to human health of REE was assessed briefly

  20. Rare earth element geochemistry characteristics of seawater and porewater from deep sea in western Pacific.

    Science.gov (United States)

    Deng, Yinan; Ren, Jiangbo; Guo, Qingjun; Cao, Jun; Wang, Haifeng; Liu, Chenhui

    2017-11-28

    Deep-sea sediments contain high concentrations of rare earth element (REE) which have been regarded as a huge potential resource. Understanding the marine REE cycle is important to reveal the mechanism of REE enrichment. In order to determine the geochemistry characteristics and migration processes of REE, seawater, porewater and sediment samples were systematically collected from the western Pacific for REE analysis. The results show a relatively flat REE pattern and the HREE (Heavy REE) enrichment in surface and deep seawater respectively. The HREE enrichment distribution patterns, low concentrations of Mn and Fe and negative Ce anomaly occur in the porewater, and high Mn/Al ratios and low U concentrations were observed in sediment, indicating oxic condition. LREE (Light REE) and MREE (Middle REE) enrichment in upper layer and depletion of MREE in deeper layer were shown in porewater profile. This study suggests that porewater flux in the western Pacific basin is a minor source of REEs to seawater, and abundant REEs are enriched in sediments, which is mainly caused by the extensive oxic condition, low sedimentation rate and strong adsorption capacity of sediments. Hence, the removal of REEs of porewater may result in widespread REE-rich sediments in the western Pacific basin.

  1. Rare earth element distributions and trends in natural waters with a focus on groundwater.

    Science.gov (United States)

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

    2014-04-15

    Systematically varying properties and reactivities have led to focused research of the environmental forensic capabilities of rare earth elements (REE). Increasing anthropogenic inputs to natural systems may permanently alter the natural signatures of REE, motivating characterization of natural REE variability. We compiled and analyzed reported dissolved REE concentration data over a wide range of natural water types (ground-, ocean, river, and lake water) and groundwater chemistries (e.g., fresh, brine, and acidic) with the goal of quantifying the extent of natural REE variability, especially for groundwater systems. Quantitative challenges presented by censored data were addressed with nonparametric distributions and regressions. Reported measurements of REE in natural waters range over nearly 10 orders of magnitude, though the majority of measurements are within 2-4 orders of magnitude, and are highly correlated with one another. Few global correlations exist among dissolved abundance and bulk solution properties in groundwater, indicating the complex nature of source-sink terms and the need for care when comparing results between studies. This collection, homogenization, and analysis of a disparate literature facilitates interstudy comparison and provides insight into the wide range of variables that influence REE geochemistry.

  2. Fracture toughness improvement of austempered high silicon steel by titanium, vanadium and rare earth elements modification

    International Nuclear Information System (INIS)

    Chen Xiang; Li Yanxiang

    2007-01-01

    The microstructure of austempered high silicon (AHS) steel before and after treating with a modifier containing titanium, vanadium and rare earth elements (so-called Ti-V-RE modifier) and austempered at different temperatures has been investigated. The plane strain fracture toughness of the steel in room temperature and ambient atmosphere has been examined. The microstructure was characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and optical metallography and correlated to the fracture toughness of the steel. The results show that the primary austenite grains are refined, the dendritic austempered structure is eliminated, and the volume of blocky shaped retained austenite is reduced by the addition of Ti-V-RE modifier. Modification with Ti-V-RE modifier can prompt the bainitic ferrite transformation and reduce the volume fraction of retained austenite. High fracture toughness is obtained for AHS steel with the addition of Ti-V-RE modifier when austempered between 350 and 385 deg. C with a retained austenite of 30-35% and the carbon content in the austenite is about 1.9-2%. The fracture toughness of AHS steel by the modification treatment can increase 10-40% than that of unmodified, an optimum value of 85 MPa m 1/2 was obtained when austempered at 385 deg. C

  3. Fracture toughness improvement of austempered high silicon steel by titanium, vanadium and rare earth elements modification

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xiang [Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Li Yanxiang [Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)]. E-mail: yanxiang@tsinghua.edu.cn

    2007-01-25

    The microstructure of austempered high silicon (AHS) steel before and after treating with a modifier containing titanium, vanadium and rare earth elements (so-called Ti-V-RE modifier) and austempered at different temperatures has been investigated. The plane strain fracture toughness of the steel in room temperature and ambient atmosphere has been examined. The microstructure was characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and optical metallography and correlated to the fracture toughness of the steel. The results show that the primary austenite grains are refined, the dendritic austempered structure is eliminated, and the volume of blocky shaped retained austenite is reduced by the addition of Ti-V-RE modifier. Modification with Ti-V-RE modifier can prompt the bainitic ferrite transformation and reduce the volume fraction of retained austenite. High fracture toughness is obtained for AHS steel with the addition of Ti-V-RE modifier when austempered between 350 and 385 deg. C with a retained austenite of 30-35% and the carbon content in the austenite is about 1.9-2%. The fracture toughness of AHS steel by the modification treatment can increase 10-40% than that of unmodified, an optimum value of 85 MPa m{sup 1/2} was obtained when austempered at 385 deg. C.

  4. The rare-earth elements: Vital to modern technologies and lifestyles

    Science.gov (United States)

    Van Gosen, Bradley S.; Verplanck, Philip L.; Long, Keith R.; Gambogi, Joseph; Seal, Robert R.

    2014-01-01

    Until recently, the rare-earth elements (REEs) were familiar to a relatively small number of people, such as chemists, geologists, specialized materials scientists, and engineers. In the 21st century, the REEs have gained visibility through many media outlets because of (1) the public has recognized the critical, specialized properties that REEs contribute to modern technology, as well as (2) China's dominance in production and supply of the REEs and (3) international dependence on China for the majority of the world's REE supply.Since the late 1990s, China has provided 85–95 percent of the world’s REEs. In 2010, China announced their intention to reduce REE exports. During this timeframe, REE use increased substantially. REEs are used as components in high technology devices, including smart phones, digital cameras, computer hard disks, fluorescent and light-emitting-diode (LED) lights, flat screen televisions, computer monitors, and electronic displays. Large quantities of some REEs are used in clean energy and defense technologies. Because of the many important uses of REEs, nations dependent on new technologies, such as Japan, the United States, and members of the European Union, reacted with great concern to China’s intent to reduce its REE exports. Consequently, exploration activities intent on discovering economic deposits of REEs and bringing them into production have increased.

  5. Radiochemical separation of thorium acetylacetonate from other thorium species

    Energy Technology Data Exchange (ETDEWEB)

    Solache Rios, M.; Tenorio, D.

    1987-01-16

    A solvent extraction technique to separate different chemical species of thorium is presented. The products formed by the chemical effects of the (n,el) reaction on the Th(acac)/sub 4/ were separated by this method and the retention value was measured. 6 refs.

  6. Earth

    CERN Document Server

    Carter, Jason

    2017-01-01

    This curriculum-based, easy-to-follow book teaches young readers about Earth as one of the eight planets in our solar system in astronomical terms. With accessible text, it provides the fundamental information any student needs to begin their studies in astronomy, such as how Earth spins and revolves around the Sun, why it's uniquely suitable for life, its physical features, atmosphere, biosphere, moon, its past, future, and more. To enhance the learning experience, many of the images come directly from NASA. This straightforward title offers the fundamental information any student needs to sp

  7. Source and mobility of Rare Earth Elements in a sedimentary aquifer system: Aquitaine basin (Southern France)

    Science.gov (United States)

    Negrel, P. J.; Petelet-Giraud, E.; Millot, R.; Malcuit, E.

    2011-12-01

    The study of rare earth elements (REEs) in natural waters initially involved an examination of their occurrence and behavior in seawater and coastal waters such as estuaries. Since the 1990s, REE geochemistry has been applied to continental waters such as rivers and lakes and groundwaters. Rare earth elements) are of great interest because of their unique characteristics and have been used in the study of many geological processes like weathering and water-rock interaction processes, provenance of sediments, etc... With the evolution of analytical techniques like new generation ICP-MS, much attention had been paid towards the water geochemistry of REEs. However, there is a need of more investigations devoted to REEs in large groundwater systems, especially on the understanding of the distribution of REEs and their evolution in such systems. In this frame, large sedimentary aquifer systems often constitute strategic water resources for drinking water supply, agriculture irrigation and industry, but can also represent an energetic resource for geothermal power. Large water abstractions can induce complete modification of the natural functioning of such aquifer systems. These large aquifer systems thus require water management at the basin scale in order to preserve both water quantity and quality. The large Eocene Sand aquifer system of the Aquitaine sedimentary basin was studied through various hydrological, chemical and isotopic tools. This system extends over 116,000 km2 in the South west part of the French territory. The aquifer being artesian in the west of the district and confined with piezometric levels around 250-m depth in the east. The 'Eocene Sands', composed of sandy Tertiary sediments alternating with carbonate deposits, is a multi-layer system with high permeability and a thickness of several tens of metres to a hundred metres. The Eocene Sand aquifer system comprises at least five aquifers: Paleocene, Eocene infra-molassic sands (IMS), early Eocene

  8. Preconcentration of rare earth elements from rocks by thin-layer chromatography and their neutron-activation determination

    International Nuclear Information System (INIS)

    Ryabukhin, V.A.; Volynets, M.P.; Myasoedov, B.F.

    1990-01-01

    Conditions were studied for separation of rare earths and accompanying elements in rocks on Fixion 50x8 thin-layer plates using solutions of oxalic acid and ammonium chloride in ammonia medium. A simple technique was developed for TLC proconcentration of rare earths followed by gamma spectrometric analysis of the irradiated fractions that enabled to determine 8-10 elements in samples with a mass of up to 30 mg. The limits of detection (μg/g) were 0.05 (Eu), 0.1 (Sm), 0.2 (Tb), 0.3 (Yb), 0.4 (La), 1.0 (Tu), 2.0 (Ce), 10 (Nd). The relative standard deviation was 0.05-0.20 at element levels 5-10 times as high as the detection limits

  9. β-decay of neutron-rich Z∼60 nuclei and the origin of rare earth elements

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J. [RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan and School of Physics and State key Laboratory of Nuclear Physics and Technology, Peking University (China); Nishimura, S.; Lorusso, G.; Baba, H.; Doornenbal, P.; Isobe, T.; Söderström, P. A.; Sakurai, H. [RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Xu, Z. Y. [Department of Physics, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, 113-0033 Tokyo (Japan); Browne, F. [School of Computing Engineering and Mathematics, University of Brighton (United Kingdom); Daido, R.; Fang, Y. F.; Yagi, A.; Nishibata, H.; Odahara, A.; Yamamoto, T. [Department of Physics, Osaka University, Machikaneyama-machi 1-1, Osaka 560-0043 Toyonaka (Japan); Ideguchi, E.; Aoi, N.; Tanaka, M. [Research Center for Nuclear Physics, Osaka University (Japan); Collaboration: EURICA Collaboration; and others

    2014-05-02

    A large fraction of the rare-earth elements observed in the solar system is produced in the astrophysical rapid neutron capture process (r-process). However, current stellar models cannot completely explain the relative abundance of these elements partially because of nuclear physics uncertainties. To address this problem, a β-decay spectroscopy experiment was performed at RI Beam Factory (RIBF) at RIKEN, aimed at studying a wide range of very neutron-rich nuclei with Z∼60 that are progenitors of the rare-earth elements with mass number A∼460. The experiment provides a test of nuclear models as well as experimental inputs for r-process calculations. This contribution presents the experimental setup and some preliminary results of the experiment.

  10. Distribution behavior of uranium, neptunium, rare-earth elements ( Y, La, Ce, Nd, Sm, Eu, Gd) and alkaline-earth metals (Sr,Ba) between molten LiClKCI eutectic salt and liquid cadmium or bismuth

    Science.gov (United States)

    Kurata, M.; Sakamura, Y.; Hijikata, T.; Kinoshita, K.

    1995-12-01

    Distribution coefficients of uranium neptunium, eight rare-earth elements (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) and two alkaline-earth metals (Sr and Ba) between molten LiCl-KCI eutectic salt and either liquid cadmium or bismuth were measured at 773 K. Separation factors of trivalent rare-earth elements to uranium or neptunium in the LiCl-KCl/Bi system were by one or two orders of magnitude larger than those in the LiCl-KCl/Cd system. On the contrary, the separation factors of alkaline-earth metals and divalent rare-earth elements to trivalent rare-earth elements were by one or two orders of magnitude smaller in the LiCl-KCl/Bi system.

  11. Distribution behavior of uranium, neptunium, rare-earth elements (Y, La, Ce, Nd, Sm, Eu, Gd) and alkaline-earth metals (Sr,Ba) between molten LiCl-KCl eutectic salt and liquid cadmium or bismuth

    International Nuclear Information System (INIS)

    Kurata, M.; Sakamura, Y.; Hijikata, T.; Kinoshita, K.

    1995-01-01

    Distribution coefficients of uranium neptunium, eight rare-earth elements (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) and two alkaline-earth metals (Sr and Ba) between molten LiCl-KCl eutectic salt and either liquid cadmium or bismuth were measured at 773 K. Separation factors of trivalent rare-earth elements to uranium or neptunium in the LiCl-KCl/Bi system were by one or two orders of magnitude larger than those in the LiCl-KCl/Cd system. On the contrary, the separation factors of alkaline-earth metals and divalent rare-earth elements to trivalent rare-earth elements were by one or two orders of magnitude smaller in the LiCl-KCl/Bi system. (orig.)

  12. Reducing uranium and thorium level in Zircon: effect of heat treatment on rate of leaching

    International Nuclear Information System (INIS)

    Meor Yusoff Meor Sulaiman

    2002-01-01

    Considerable amount of uranium and thorium are found in Malaysian zircon and the level is much higher than the minimum value adopted by many importing countries. Selective leaching had been applied as an important technique to reduce these elements. An initial study was carried out using hydrochloric acid leaching system but the result was not favourable. The rate of uranium and thorium leached can be further improved by introducing a heat pretreatment process prior to leaching (Author)

  13. Rare earth, major and trace element composition of Leg 127 sediments

    Science.gov (United States)

    Murray, R.W.; Buchholtz ten Brink, Marilyn R.; Brumsack, Hans-Juergen; Gerlach, David C.; Russ III, G. Price

    1992-01-01

    The relative effects of paleoceanographic and paleogeographic variations, sediment lithology, and diagenetic processes on the final preserved chemistry of Japan Sea sediments are evaluated by investigating the rare earth element (REE), major element, and trace element concentrations in 59 squeeze-cake whole-round and 27 physical-property sample residues from Sites 794, 795, and 797, cored during ODP Leg 127. The most important variation in sedimentary chemical composition is the increase in SiO2 concentration through the Pliocene diatomaceous sequences, which dilutes most other major and trace element components by various degrees. This biogenic input is largest at Site 794 (Yamato Basin), moderately developed at Site 797 (Yamato Basin), and of only minor importance at Site 795 (Japan Basin), potentially reflecting basinal contrasts in productivity with the Yamato Basin recording greater biogenic input than the Japan Basin and with the easternmost sequence of Site 794 lying beneath the most productive waters. There are few systematic changes in solid-phase chemistry resulting from the opal-A/opal-CT or opal-CT/quartz silica phase transformations. Most major and trace element concentrations are controlled by the aluminosilicate fraction of the sediment, although the effects of diagenetic silica phases and manganese carbonates are of localized importance. REE total abundances (IREE) in the Japan Sea are strongly dependent upon the paleoceanographic position of a given site with respect to terrigenous and biogenic sources. REE concentrations at Site 794 overall correspond well to aluminosilicate chemical indices and are strongly diluted by SiO2 within the upper Miocene-Pliocene diatomaceous sequence. Eu/Eu* values at Site 794 reach a maximum through the diatomaceous interval as well, most likely suggesting an association of Eu/Eu* with the siliceous component, or reflecting slight incorporation of a detrital feldspar phase. XREE at Site 795 also is affiliated strongly

  14. Radiochemical neutron-activation analysis of uncertified ultra-trace rare earth elements in two biological certified reference materials

    International Nuclear Information System (INIS)

    Cao, Lei; Tian, Weizhi; Ni, Bangfa; Wang, Pingsheng; Zhang, Yangmei

    2002-01-01

    Radiochemical neutron activation analysis (RNAA) has been used for the determination of eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) in two Chinese certified reference materials (CRM), GBW 08503 (wheat powder) and GBW 09101 (human hair). These determinations are important for possible certification of the above mentioned ultra-trace elements, so far not certified. A simple one-step (REE)F 3 precipitation was used. Chemical yields were determined for all relevant elements by means of tracer experiments. The two CRM were also analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) to compare the merits and drawbacks of these two major trace analytical techniques for these particular elements. RNAA was proven to be a reliable technique for ultra-trace analysis, especially in the certification of some ultra-trace elements. (orig.)

  15. The impact of transport processes on rare earth element patterns in marine authigenic and biogenic phosphates

    Science.gov (United States)

    Auer, Gerald; Reuter, Markus; Hauzenberger, Christoph A.; Piller, Werner E.

    2017-04-01

    Rare earth elements (REEs) are commonly used proxies to reconstruct water chemistry and oxygen saturation during the formation of authigenic and biogenic phosphates in marine environments. In the modern ocean REEs exhibit a distinct pattern with enrichment of heavy REEs and strong depletion in cerium (Ce). The wide range of REE enrichment patterns found in ancient marine phosphates lead to the proposition that water chemistry has been very different in the Earth's past. However, both early and late diagenesis are known to affect REE signatures in phosphates altering primary marine signals. Herein we present a dataset of REE signatures in 38 grain specific LA-ICP-MS measurements of isolated phosphate and carbonate grains in three discrete rock samples. The phosphates mainly consist of authigenic phosphates and phosphatized microfossils that formed in a microbially mediated micro-milieu. In addition, isolated biogenic and reworked phosphatic grains are also present. The phosphates are emplaced in bioclastic grain- to packstones deposited on a carbonate ramp setting in the central Mediterranean Sea during the middle Miocene Monterey event. The results reveal markedly different REE patterns (normalized to the Post Archean Australian Shale standard) in terms of total enrichment and pattern shape. Analyses of REE diagenesis proxies show that diagenetic alteration affected the samples only to a minor degree. Grain shape and REE patterns together indicate that authigenic, biogenic and reworked phosphates have distinct REE patterns irrespective of the sample. Our study shows that while REE patterns in phosphates do reflect water chemistry during authigenesis, they are often already heavily altered during reworking, a process, which can occur in geologically negligible timespans. REE patterns are therefore more likely to reflect complex enrichment processes after their formation. Similarities in the REE patterns of reworked and biogenic phosphate further suggest that the

  16. Thorium in occupationally exposed men

    International Nuclear Information System (INIS)

    Stehney, A. F.

    1999-01-01

    Higher than environmental levels of 232 Th have been found in autopsy samples of lungs and other organs from four former employees of a thorium refinery. Working periods of the subjects ranged from 3 to 24 years, and times from end of work to death ranged from 6 to 31 years. Examination of the distribution of thorium among the organs revealed poor agreement with the distribution calculated from the dosimetric models in Publication 30 of the International Commission on Radioprotection (ICRP). Concentrations in the lungs relative to pulmonary lymph nodes, bone or liver were much higher than calculated from the model for class Y thorium and the exposure histories of the workers. Much better agreement was found with more recently proposed models in Publications 68 and 69 of the ICRP. Radiation doses estimated from the amounts of thorium in the autopsy samples were compatible with health studies that found no significant difference in mortality from that of the general population of men in the US

  17. [Indirect determination of rare earth elements in Chinese herbal medicines by hydride generation-atomic fluorescence spectrometry].

    Science.gov (United States)

    Zeng, Chao; Lu, Jian-Ping; Xue, Min-Hua; Tan, Fang-Wei; Wu, Xiao-Yan

    2014-07-01

    Based on their similarity in chemical properties, rare earth elements were able to form stable coordinated compounds with arsenazo III which were extractable into butanol in the presence of diphenylguanidine. The butanol was removed under reduced pressure distillation; the residue was dissolved with diluted hydrochloric acid. As was released with the assistance of KMnO4 and determined by hydrogen generation-atomic fluorescence spectrometry in terms of rare earth elements. When cesium sulfate worked as standard solution, extraction conditions, KMnO4 amount, distillation temperature, arsenazo III amount, interfering ions, etc were optimized. The accuracy and precision of the method were validated using national standard certified materials, showing a good agreement. Under optimum condition, the linear relationship located in 0.2-25 microg x mL(-1) and detection limit was 0.44 microg x mL(-1). After the herbal samples were digested with nitric acid and hydrogen peroxide, the rare earth elements were determined by this method, showing satisfactory results with relative standard deviation of 1.3%-2.5%, and recoveries of 94.4%-106.0%. The method showed the merits of convenience and rapidness, simple instrumentation and high accuracy. With the rare earths enriched into organic phase, the separation of analytes from matrix was accomplished, which eliminated the interference. With the residue dissolved by diluted hydrochloric acid after the solvent was removed, aqueous sample introduction eliminated the impact of organic phase on the tubing connected to pneumatic pump.

  18. HIGH PERCENTAGE OF RARE EARTH ELEMENT CONNECTION WITH THE ACCUMULATION SEDIMENT AS RESPONSE LONGSHORE CURRENTS IN THE BELITUNG WATERS

    Directory of Open Access Journals (Sweden)

    Delyuzar Ilahude

    2017-07-01

    Full Text Available The study area is geographically located in the West coast of Belitung island at coordinates 105o48'00" - 106o06' 00" E and 06o46'00" - 06o50' 00" S. The beach and coastal area is influenced by wave energy from the West and North directions The purpose of this study is to analyze the relationship between the zone of sediment accumulation of empirical approaches on oceanography parameter containing rare earth elements. The approach used is to predict the shore wave energy using wave prediction curve deep waters to obtain the energy flux of the wave at each point of reference. Sediments containing rare earth elements tend to lead to the south as a result of the movement of longshore currents. Regional coastal area of the western part of the island of Belitung, especially in the southern part of the estuary of the river Tanjung Pandan is estimated to be a zone of sediment accumulation. The movement of sediment caused by wave energy from the north led to sedimentation evolved significantly in the south which is thought to contain rare earths minerals derived from land. This sedimentation process takes place on a seasonal basis, which allegedly took place in the west. The movement of sediment to the south of the mouth of the Cerucuk River it is predicted that rare earth elements were supplied from these rivers tend to settle in the southern part of the estuary Cerucuk throughout the year.

  19. Thorium determination by x-ray fluorescence spectrometry in simulated thorex process solutions

    International Nuclear Information System (INIS)

    Yamaura, M.; Matsuda, H.T.

    1991-11-01

    The X-ray fluorescence method for thorium determination in aqueous and organic (TBP/n-dodecane) solutions is described. The thin film technique for sample preparation and a suitable internal standard had been used. The best conditions for Thorium determination had been established studying some parameters as analytical line, internal standard, filter paper, paper geometry, sample volume and measurement conditions. With the established conditions, thorium was concentration range of to 200 g Th/L and in organic solutions (2-63g Th/L) with 1,5% of precision. The accuracy of the proposed method was 3% in aqueous and organic phases. The detection limit was 1,2μg thorium for aqueous solutions and 1,4μg for organic solutions. Uranium, fission products, corrosion products and Thorex reagent components were studied as interfering elements in the thorium analysis. The matrix effect was also studied using the Thorex process simulated solutions. Finally, the method was applied to thorium determination in irradiated thorium solutions with satisfactory results. (author)

  20. Controlled synthesis of thorium and uranium oxide nano-crystals

    International Nuclear Information System (INIS)

    Hudry, Damien; Apostolidis, Christos; Walter, Olaf; Gouder, Thomas; Courtois, Eglantine; Kubel, Christian; Meyer, Daniel

    2013-01-01

    Very little is known about the size and shape effects on the properties of actinide compounds. As a consequence, the controlled synthesis of well-defined actinide-based nano-crystals constitutes a fundamental step before studying their corresponding properties. In this paper, we report on the non-aqueous surfactant-assisted synthesis of thorium and uranium oxide nano-crystals. The final characteristics of thorium and uranium oxide nano-crystals can be easily tuned by controlling a few experimental parameters such as the nature of the actinide precursor and the composition of the organic system (e.g., the chemical nature of the surfactants and their relative concentrations). Additionally, the influence of these parameters on the outcome of the synthesis is highly dependent on the nature of the actinide element (thorium versus uranium). By using optimised experimental conditions, monodisperse isotropic uranium oxide nano-crystals with different sizes (4.5 and 10.7 nm) as well as branched nano-crystals (overall size ca. 5 nm), nano-dots (ca. 4 nm) and nano-rods (with ultra-small diameters of 1 nm) of thorium oxide were synthesised. (authors)