Determination of americium in urine

International Nuclear Information System (INIS)

Shvydko, N.S.; Mikhajlova, O.A.; Popov, D.K.

1988-01-01

A technique has been developed for the determination of americium 241 in urine by a raiochemical purification of the nuclide from uranium (upon co-precipitation of americium 241 with calcium and lanthanum), plutonium, thorum, and polonium 210 (upon co-precipitation of these radionuclides with zirconium iodate). α-Radioactivity was measured either in a thick layer of the americium 241 precipitate with a nonisotope carrier or in thin-layer preparations after electrolytic precipitation of americium 241 on a cathode

Contributions to the preparation of 241americium metal and a few 241americium silicides

International Nuclear Information System (INIS)

Wittmann, F.D.

1980-01-01

In order to take a closer look at the americium-silicon system, three further silicides of americium: Am 5 Si 3 , Am 2 Si 3 and AmSi 2 were prepared in addition to the already known americium monosilicide and starting from the knowledge gained from the latters preparation. Radiographic investigations were carried out into the temperature region of 900 0 C. They showed no change of structure in the three compounds. It was possible to prepare residue-free americium metal by reducing AmF 3 with Si, whereby the SiF 4 formed can be easily separated off as volatile compound, and the Am metal is brought into a very pure form by sublimation suitable for spectrochemical investigations. Attempts to prepare binary germanides and gallides of 241 americium were unsuccessful. (RB) [de

Americium in the Finnish environment

Energy Technology Data Exchange (ETDEWEB)

Lehto, J. (Helsinki Univ., Lab. of Radiochemistry (Finland))

2009-07-01

This paper reviews studies on environmental americium,241 Am, in Finland. There are two sources of americium in the Finnish environment: fallouts from nuclear weapons tests in the 1950s and 1960s and from the Chernobyl accident in 1986, the former constituting around 98% of the total environmental load. The weapons test fallout was distributed more or less uniformly over Finland, while the Chernobyl fallout was deposited on a sector from southwestern coast to northeast. The total deposition of 241 Am in Finland is approximately 20 Bq m-2 and the amount is still somewhat increasing due to decay of 241 Pu. In this paper, the distribution and migration of americium in forest and aquatic environments is described. Americium concentrations in natural waters, sediments, soils, vegetation and fishes are given. In addition, the behaviour of americium in the food chain from lichen via reindeer into man is discussed. Radiation doses to humans due to the environmental americium in Finland are of no practical importance (orig.)

Rare earth elements: end use and recyclability

Science.gov (United States)

Goonan, Thomas G.

2011-01-01

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

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.

Distribution of uranium, americium and plutonium in the biomass of freshwater macrophytes

Energy Technology Data Exchange (ETDEWEB)

Zotina, T.A.; Kalacheva, G.S.; Bolsunovsky, A.YA. [Institute of Biophysics SB RAS, Akademgorodok, Krasnoyarsk (Russian Federation)

2010-07-01

Accumulation of uranium ({sup 238}U), americium ({sup 241}Am) and plutonium ({sup 242}Pu) and their distribution in cell compartments and biochemical components of the biomass of aquatic plants Elodea canadensis, Ceratophyllum demersum, Myrioplyllum spicatum and aquatic moss Fontinalis antipyretica have been investigated in laboratory batch experiments. Isotopes of uranium, americium and plutonium taken up from the water by Elodea canadensis apical shoots were mainly absorbed by cell walls, plasmalemma and organelles. A small portion of isotopes (about 6-13 %) could be dissolved in cytoplasm. The major portion (76-92 %) of americium was bound to cell wall cellulose-like polysaccharides of Elodea canadensis, Myriophyllum spicatum, Ceratophyllum demersum and Fontinalis antipyretica, 8-23 % of americium activity was registered in the fraction of proteins and carbohydrates, and just a small portion (< 1%) in lipid fraction. The distribution of plutonium in the biomass fraction of Elodea was similar to that of americium. Hence, americium and plutonium had the highest affinity to cellulose-like polysaccharides in Elodea biomass. Distribution of uranium in the biomass of Elodea differed essentially from that of transuranium elements: a considerable portion of uranium was recorded in the fraction of protein and carbohydrates (51 %). From our data we can assume that uranium has higher affinity to carbohydrates than proteins. (authors)

Distribution of uranium, americium and plutonium in the biomass of freshwater macrophytes

International Nuclear Information System (INIS)

Zotina, T.A.; Kalacheva, G.S.; Bolsunovsky, A.YA.

2010-01-01

Accumulation of uranium ( 238 U), americium ( 241 Am) and plutonium ( 242 Pu) and their distribution in cell compartments and biochemical components of the biomass of aquatic plants Elodea canadensis, Ceratophyllum demersum, Myrioplyllum spicatum and aquatic moss Fontinalis antipyretica have been investigated in laboratory batch experiments. Isotopes of uranium, americium and plutonium taken up from the water by Elodea canadensis apical shoots were mainly absorbed by cell walls, plasmalemma and organelles. A small portion of isotopes (about 6-13 %) could be dissolved in cytoplasm. The major portion (76-92 %) of americium was bound to cell wall cellulose-like polysaccharides of Elodea canadensis, Myriophyllum spicatum, Ceratophyllum demersum and Fontinalis antipyretica, 8-23 % of americium activity was registered in the fraction of proteins and carbohydrates, and just a small portion (< 1%) in lipid fraction. The distribution of plutonium in the biomass fraction of Elodea was similar to that of americium. Hence, americium and plutonium had the highest affinity to cellulose-like polysaccharides in Elodea biomass. Distribution of uranium in the biomass of Elodea differed essentially from that of transuranium elements: a considerable portion of uranium was recorded in the fraction of protein and carbohydrates (51 %). From our data we can assume that uranium has higher affinity to carbohydrates than proteins. (authors)

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)

Solubility of Plutonium (IV) Oxalate During Americium/Curium Pretreatment

International Nuclear Information System (INIS)

Rudisill, T.S.

1999-01-01

Approximately 15,000 L of solution containing isotopes of americium and curium (Am/Cm) will undergo stabilization by vitrification at the Savannah River Site (SRS). Prior to vitrification, an in-tank pretreatment will be used to remove metal impurities from the solution using an oxalate precipitation process. Material balance calculations for this process, based on solubility data in pure nitric acid, predict approximately 80 percent of the plutonium in the solution will be lost to waste. Due to the uncertainty associated with the plutonium losses during processing, solubility experiments were performed to measure the recovery of plutonium during pretreatment and a subsequent precipitation process to prepare a slurry feed for a batch melter. A good estimate of the plutonium content of the glass is required for planning the shipment of the vitrified Am/Cm product to Oak Ridge National Laboratory (ORNL).The plutonium solubility in the oxalate precipitation supernate during pretreatment was 10 mg/mL at 35 degrees C. In two subsequent washes with a 0.25M oxalic acid/0.5M nitric acid solution, the solubility dropped to less than 5 mg/mL. During the precipitation and washing steps, lanthanide fission products in the solution were mostly insoluble. Uranium, and alkali, alkaline earth, and transition metal impurities were soluble as expected. An elemental material balance for plutonium showed that greater than 94 percent of the plutonium was recovered in the dissolved precipitate. The recovery of the lanthanide elements was generally 94 percent or higher except for the more soluble lanthanum. The recovery of soluble metal impurities from the precipitate slurry ranged from 15 to 22 percent. Theoretically, 16 percent of the soluble oxalates should have been present in the dissolved slurry based on the dilution effects and volumes of supernate and wash solutions removed. A trace level material balance showed greater than 97 percent recovery of americium-241 (from the beta dec

Accidental exposure to americium

International Nuclear Information System (INIS)

Heid, K.R.

1985-04-01

This report desribes an accident in which a 64-year old Hanford nuclear worker was exposed to high levels of americium while working in an americium recovery facility in 1976. As a result of the accident, he was heavily externally contaminated with americium, sustained with a substantial internal deposition of this isotope, and was burned with concentrated nitric acid and injured by flying debris about the face and neck. The immediate and longer-term treatment given the patient, including the decontamination efforts and clinical laboratory studies, are discussed. Special in-vivo equipment and techniques were used to measure the americium deposited in the patient. These and subsequent in-vivo measurements were used to estimate the dose rates and the accumulated doses to body organs. Urinary and fecal excreta were collected and analyzed for americium content. The interpretation of these data was complicated by the fact that the intake resulted both from inhalation and from solubilization of the americium embedded in facial tissues as a result of the accident. A total of 1100 μCi was excreted in urine and feces during the first 2 years following the accident. The long-term use of diethylenetriaminepentaacetic acid (DTPA), used principally as the zinc salt, is discussed including the method, route of administration, and effectiveness. To date, the patient has apparently experienced no complications attributable to this extensive course of therapy, even though he was given approximately 560 g of DTPA. 6 refs

Extraction separation of americium and curium. A review

International Nuclear Information System (INIS)

Petrzilova, H.

1976-11-01

A survey is given of extraction systems suitable for transplutonium element separation and preparation as well as for the practical application of their nuclear properties. Methods are discussed in detail of separating the actinide and the lanthanide fractions from fission and corrosion products and of separating americium from curium. The description is completed with flowsheets showing the separation of transplutonium elements from irradiated targets and waste solutions after spent fuel reprocessing. (L.K.)

Rare earth elements behavior in Peruibe black mud

International Nuclear Information System (INIS)

Torrecilha, Jefferson K.; Carvalho, Leandro P.; Gouvea, Paulo F.M.; Silva, Paulo S.C. da

2015-01-01

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

Rare earth elements behavior in Peruibe black mud

Energy Technology Data Exchange (ETDEWEB)

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

2015-07-01

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

On the americium oxalate solubility

International Nuclear Information System (INIS)

Zakolupin, S.A.; Korablin, Eh.V.

1977-01-01

The americium oxalate solubility at different nitric (0.0-1 M) and oxalic (0.0-0.4 M) acid concentrations was investigated in the temperature range from 14 to 60 deg C. The dependence of americium oxalate solubility on the oxalic acid concentration was determined. Increasing oxalic acid concentration was found to reduce the americium oxalate solubility. The dependence of americium oxalate solubility on the oxalic acid concentration was noted to be a minimum at low acidity (0.1-0.3 M nitric acid). This is most likely due to Am(C 2 O 4 ) + , Am(C 2 O 4 ) 2 - and Am(C 2 O 4 ) 3 3- complex ion formation which have different unstability constants. On the basis of the data obtained, a preliminary estimate was carried out for the product of americium oxalate solubility in nitric acid medium (10 -29 -10 -31 ) and of the one in water (6.4x10 -20 )

Isolation of high purity americium metal via distillation

Science.gov (United States)

Squires, Leah N.; King, James A.; Fielding, Randall S.; Lessing, Paul

2018-03-01

Pure americium metal is a crucial component for the fabrication of transmutation fuels. Unfortunately, americium in pure metal form is not available; however, a number of mixed metals and mixed oxides that include americium are available. In this manuscript a method is described to obtain high purity americium metal from a mixture of americium and neptunium metals with lead impurity via distillation.

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

Decontaminaion of metals containing plutonium and americium

International Nuclear Information System (INIS)

Seitz, M.G.; Gerding, T.J.; Steindler, M.J.

1979-06-01

Melt-slagging (melt-refining) techniques were evaluated as a decontamination and consolidation step for metals contaminated with oxides of plutonium and americium. Experiments were performed in which mild steel, stainless steel, and nickel contaminated with oxides of plutonium and americium were melted in the presence of silicate slags of various compositions. The metal products were low in contamination, with the plutonium and americium strongly fractionated to the slags. Partition coefficients (plutonium in slag/plutonium in steel) of 7 x 10 6 were measured with boro-silicate slag and of 3 x 10 6 with calcium, magnesium silicate slag. Decontamination of metals containing as much as 14,000 ppM plutonium appears to be as efficient as for metals with plutonium levels of 400 ppM. Staged extraction, that is, a remelting of processed metal with clean slag, results in further decontamination of the metal. The second extraction is effective with either resistance-furnace melting or electric-arc melting. Slag adhering to the metal ingots and in defects within the ingots is in the important contributors to plutonium retained in processed metals. If these sources of plutonium are controlled, the melt-refining process can be used on a large scale to convert highly contaminated metals to homogeneous and compact forms with very low concentrations of plutonium and americium. A conceptual design of a melt-refining process to decontaminate plutonium- and americium-contaminated metals is described. The process includes single-stage refining of contaminated metals to produce a metal product which would have less than 10 nCi/g of TRU-element contamination. Two plant sizes were considered. The smaller conceptual plant processes 77 kg of metal per 8-h period and may be portable.The larger one processes 140 kg of metal per 8-h period, is stationary, and may be near te maximum size that is practical for a metal decontamination process

Metabolism of americium-241 in dairy animals

International Nuclear Information System (INIS)

Sutton, W.W.; Patzer, R.G.; Mullen, A.A.; Hahn, P.B.; Potter, G.D.

1978-10-01

Groups of lactating cows and goats were used to examine americium-241 metabolism in dairy animals. Following either single oral or intravenous nuclide doses, samples of milk, urine, blood, and feces were taken over a 168-hr collection period and the americium concentrations were determined by gamma counting. Gastrointestinal uptake of americium by both cows and goats was estimated to be 0.014% of the respective oral doses. The cumulative percentage of oral dose transported to milk and urine was 4.4 x 10 -4 and 1.1 x 10 -3 respectively for cows and 4.4 x 10 -3 and 1.2 x 10 -3 respectively for goats. The relatively high americium concentrations noted in caprine milk following the oral doses are discussed. Plasma concentrations of americium decreased rapidly following all intravenous injections. The average percentage of injected americium transferred to milk, urine, and feces was 3, 6, and 2% respectively for cows and 2, 4, and 2% respectively for goats. In both intravenously dosed groups, approximately 30% of all americium released from the body was found in the urine during the first 24 hrs after injection. All animals were sacrificed 8 to 9 days after dosing. Bovine bone retained the greatest fraction of the administered dose followed by the liver. However, liver retained the greatest amount of americium in the goats following both oral and intravenous doses. Comparisons are presented between americium-241 and plutonium-238 transport in dairy cows

Metabolism of americium-241 in dairy animals

International Nuclear Information System (INIS)

Sutton, W.W.; Patzer, R.G.; Mullen, A.A.; Hahn, P.B.; Potter, G.D.

1978-01-01

Groups of lactating cows and goats were used to examine americium-241 metabolism in dairy animals. Following either single oral or intravenous nuclide doses, samples of milk, urine, blood, and feces were taken over a 168-hour collection period, and the americium concentrations were determined by gamma counting. Gastrointestinal uptake of americium by cows and goats was estimated to be 0.014 and 0.016% of the oral dose, respectively. The cumulative percentage of oral dose transported to milk and urine was 4.4 x 10 -4 and 1.1 x 10 -3 , respectively, for cows and 5.6 x 10 -4 and 1.2 x 10 -3 , respectively, for goats. Plasma concentrations of americium decreased rapidly following all intravenous injections. The average percentage of injected americium transferred to milk, urine, and feces was 3, 6, and 2%, respectively, for cows, and 2, 4, and 2%, respectively, for goats. In both intravenously dosed groups, approximately 30% of all americium released from the body was found in the urine during the first 24 hours after injection. All animals were sacrificed 8 to 9 days after dosing. Bovine bone retained the greatest fraction of the administered dose followed by liver and kidney. However, liver retained the greatest amount of americium in the goats following both oral and intravenous doses. Comparisons are presented between americium-241 and plutonium-238 transport in dairy cows

Production of americium isotopes in France

International Nuclear Information System (INIS)

Koehly, G.; Bourges, J.; Madic, C.; Nguyen, T.H.; Lecomte, M.

1984-12-01

The program of productions of americium 241 and 243 isotopes is based respectively on the retreatment of aged plutonium alloys or plutonium dioxide and on the treatment of plutonium targets irradiated either in CELESTIN reactors for Pu-Al alloys or OSIRIS reactor for plutonium 242 dioxide. All the operations, including americium final purifications, are carried out in hot cells equipped with remote manipulators. The chemical processes are based on the use of extraction chromatography with hydrophobic SiO 2 impregnated with extracting agents. Plutonium targets and aged plutonium alloys are dissolved in nitric acid using conventional techniques while plutonium dioxide dissolutions are performed routine at 300 grams scale with electrogenerated silver II in 4M HNO 3 at room temperature. The separation between plutonium and americium is performed by extraction of Pu(IV) either on TBP/SiO 2 or TOAHNO 3 /SiO 2 column. Americium recovery from waste streams rid of plutonium is realized by chromatographic extraction of Am(III) using mainly TBP and episodically DHDECMP as extractant. The final purification of both americium isotopes uses the selective extraction of Am(VI) on HDDiBMP/SiO 2 column at 60 grams scale. Using the overall process a total amount of 1000 grams of americium 241 and 100 grams of americium 243 has been produced nowadays and the AmO 2 final product indicates a purity better than 98.5%

Redox chemistry of americium in nitric acid media

Energy Technology Data Exchange (ETDEWEB)

Picart, S.; Jobelin, I.; Armengol, G.; Adnet, JM

2004-07-01

The redox properties of the actinides are very important parameters for speciation studies and spent nuclear fuel reprocessing based on liquid-liquid extraction of actinides at different oxidation states (as in the Purex or Sesame process). They are also very useful for developing analytical tools including coulometry and redox titration. This study addressed the americium(IV)/americium(III) and americium(VI)/americium(V) redox couples, focusing on exhaustive acquisition of the thermodynamic and kinetic parameters of americium oxidation at an electrode in a complexing nitric acid medium. (authors)

Redox chemistry of americium in nitric acid media

International Nuclear Information System (INIS)

Picart, S.; Jobelin, I.; Armengol, G.; Adnet, JM.

2004-01-01

The redox properties of the actinides are very important parameters for speciation studies and spent nuclear fuel reprocessing based on liquid-liquid extraction of actinides at different oxidation states (as in the Purex or Sesame process). They are also very useful for developing analytical tools including coulometry and redox titration. This study addressed the americium(IV)/americium(III) and americium(VI)/americium(V) redox couples, focusing on exhaustive acquisition of the thermodynamic and kinetic parameters of americium oxidation at an electrode in a complexing nitric acid medium. (authors)

Americium-241 and -243 as an ion-engine propellant

International Nuclear Information System (INIS)

Schachter, M.M.

1994-01-01

Commercially available americium-241 and -243 can be obtained as the mixture of the two isotopes in 100-gram quantities--a product of reprocessing spent nuclear powerplant fuel elements along with plutonium. The half-lives of the isotopes are 450 years for the -241 and 8,000 years for the -243 (the plutonium half-life isotope so obtained is 24,000 years). Americium rolled out in thin foil sheets emits alpha-rays (helium-4 ions) and beta-rays--2 valence electrons for each helium ion. Electrons are also considered as ions. As a foil, the americium radiates only a minimal amount of gamma-rays via the Curie effect. With appropriately designed permanent magnet rings insulated with Wood's alloy, the + and - ions can be accelerated from their already 5.5 million electron-Volts to billion and even trillions of electron-Volts by electronic control grids powered by the magnetohydrodynamic effect of electrons and helium ions streaming at the post-rocket nozzle of the ion engine. Protocol for the estimated thrust of this ion rocket engine is more than ten kilograms continuously sustainable for several thousand years

1976 Hanford americium accident

International Nuclear Information System (INIS)

Heid, K.R.; Breitenstein, B.D.; Palmer, H.E.; McMurray, B.J.; Wald, N.

1979-01-01

This report presents the 2.5-year medical course of a 64-year-old Hanford nuclear chemical operator who was involved in an accident in an americium recovery facility in August 1976. He was heavily externally contaminated with americium, sustained a substantial internal deposition of this isotope, and was burned with concentrated nitric acid and injured by flying debris about the face and neck. The medical care given the patient, including the decontamination efforts and clinical laboratory studies, are discussed. In-vivo measurements were used to estimate the dose rates and the accumulated doses to body organs. Urinary and fecal excreta were collected and analyzed for americium content. Interpretation of these data was complicated by the fact that the intake resulted both from inhalation and from solubilization of the americium embedded in facial tissues. A total of 1100 μCi was excreted in urine and feces during the first 2 years following the accident. The long-term use of diethylenetriaminepentate (DTPA), used principally as the zinc salt, is discussed including the method, route of administration, and effectiveness. To date, the patient has apparently experienced no complications attributable to this extensive course of therapy, even though he has been given approximately 560 grams of DTPA. 4 figures, 1 table

Plutonium and americium separation from salts

International Nuclear Information System (INIS)

Hagan, P.G.; Miner, F.J.

1976-01-01

Salts or materials containing plutonium and americium are dissolved in hydrochloric acid, heated, and contacted with an alkali metal carbonate solution to precipitate plutonium and americium carbonates which are thereafter readily separable from the solution

Root uptake of transuranic elements

International Nuclear Information System (INIS)

Schulz, R.K.

1977-01-01

The uptake of elements by plant roots is one of the important pathways of entry of many elements into the food chain of man. Data are cited showing plutonium concentration ratios, plant/soil, ranging from 10 -10 to 10 -3 . Concentration ratios for americium range from 10 -7 to 10 +1 . Limited experiments with curium and neptunium indicate that root uptake of curium is similar to that of americium and that plant uptake of neptunium is substantially larger than that of curium and americium. The extreme ranges of concentration ratios cited for plutonium and americium are due to a number of causes. Experimental conditions such as very intensive cropping will lead to abnormally high concentration ratios. In some experiments, addition of chelating agents markedly increased plant root uptake of transuranic elements. Particle size and composition of the source material influenced uptake of the transuranics by plants. Translocation within the plant, and soil factors such as pH and organic matter content, all affect concentration ratios

Rare Earth Elements Distribution in Beryl

International Nuclear Information System (INIS)

El Gawish, H.K.; Nada, N.; Ghaly, W.A.; Helal, A.I.

2012-01-01

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

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

International Nuclear Information System (INIS)

Selle, J.E.

1992-01-01

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

Analysis of Americium in Transplutonium Process Solutions

International Nuclear Information System (INIS)

Ferguson, R.B.

2001-01-01

One of the more difficult analyses in the transplutonium field is the determination of americium at trace levels in a complex matrix such as a process dissolver solution. Because of these conditions a highly selective separation must precede the measurement of americium. The separation technique should be mechanically simple to permit remote operation with master-slave manipulators. For subsequent americium measurement by the mass spectroscopic isotopic-dilution technique, plutonium and curium interferences must also have been removed

Cermets based on rhenium and rare earth element oxides

International Nuclear Information System (INIS)

Varfolomeev, M.B.; Velichko, A.V.; Zajtseva, L.L.; Shishkov, N.V.

1977-01-01

The reduction of perrhenates of rare earth elements and of yttrium by hydrogen and the subsequent sintering have yielded cermets based on rhenium and rare earth element oxides inherent in which are more disperse and homogeneous structures than those of the ''molecular'' rare earth element-Tc cermets. The dispersity of cermets increases in the rare earth elements series from La to Lu. The microhardness of the Re phase in cermets is 490 kgf/mm 2 ; the total microhardness of a cermet is substantially higher

Optimization conditions for the separation of rare earth elements, americium, curium and cesium with HPLC technique

International Nuclear Information System (INIS)

Goutelard, F.; Caussignac, C.; Brennetot, R.; Stadelmann, G.; Gautier, C.

2009-01-01

In order to validate the neutronic code calculations used in the nuclear field, it is necessary to quantify the isotopic composition of the nuclear irradiated fuels with high precision and accuracy. A separation step whose objective is to isolate the elements of interest in a fraction as pure as possible, is performed before mass spectrometry detection (MC-ICP-MS, TIMS), in order to eliminate isobaric interferences. In a first step, uranium and plutonium are separated from the fission products by ion exchange chromatography. Then, fission products are separated by high performance liquid chromatography (HPLC). A gradient separation with a silica sulphonated support as stationary phase and hydroxy-methyl butyric acid (HMB) as eluent solution provides a good degree of separation of the rare earth elements, Am, Cm and Cs. But, for a same manufacturer, the rate of sulphonated groups is variable from one column to another for a given production batch. For every replacement of column, it is necessary to adjust the separation conditions. Furthermore, the high radioactivity of the samples injected damages the stationary phase, dragging a regular renewal of the columns. The goal of this study is to determine the optimal separation conditions with a minimum of tests in order to limit the time assigned to this operation. A first Doehlert experimental design with pH and HMB concentration as variables has been implemented to optimize Gd, Eu separation, in isocratic initial conditions. A second one has been tested in order to separate the higher lanthanides and to fix the final conditions of the gradient separation. A last set of tests has been performed to characterize the cesium behaviour. Finally, the gradient conditions have been adjusted in order to perform the full separation of lanthanides, Cs, Am and Cm with nuclear facilities. (author)

Transmutation of Americium in Fast Neutron Facilities

OpenAIRE

Zhang, Youpeng

2011-01-01

In this thesis, the feasibility to use a medium sized sodium cooled fast reactor fully loaded with MOX fuel for efficient transmutation of americium is investigated by simulating the safety performance of a BN600-type fast reactor loaded with different fractions of americium in the fuel, using the safety parameters obtained with the SERPENT Monte Carlo code. The focus is on americium mainly due to its long-term contribution to the radiotoxicity of spent nuclear fuel and its deterioration on c...

Americium thermodynamic data for the EQ3/6 database

International Nuclear Information System (INIS)

Kerrisk, J.F.

1984-07-01

Existing thermodynamic data for aqueous and solid species of americium have been reviewed and collected in a form that can be used with the EQ3/6 database. Data that are important in solubility calculations for americium at a proposed Yucca Mountain nuclear waste repository were emphasized. Conflicting data exist for americium complexes with carbonates. Essentially no data are available for americium solids or complexes at temperatures greater than 25 0 C. 17 references, 4 figures

Status of Americium-241 recovery at Rocky Flats Plant

International Nuclear Information System (INIS)

Knighton, J.B.; Hagan, P.G.; Navratil, J.D.; Thompson, G.H.

1981-01-01

This paper is presented in two parts: Part I, Molten Salt Extraction of Americium from Molten Plutonium Metal, and Part II, Aqueous Recovery of Americium from Extraction Salts. The Rocky Flats recovery process used for waste salts includes (1) dilute hydrochloric acid dissolution of residues; (2) cation exchange to convert from the chloride to the nitrate system and to remove gross amounts of monovalent impurities; (3) anion exchange separation of plutonium; (4) oxalate precipitation of americium; and (5) calcination of the oxalate at 600 0 C to yield americium oxide. The aqueous process portion describes attempts to improve the recovery of americium. The first part deals with modifications to the cation exchange step; the second describes development of a solvent extractions process that will recovery americium from residues containing aluminium as well as other common impurities. Results of laboratory work are described. 3 figures, 6 tables. (DP)

Plutonium-239 and americium-241 uptake by plants from soil. Final report

International Nuclear Information System (INIS)

Brown, K.W.

1979-03-01

Alfalfa was grown in soil contaminated with plutonium-239 dioxide (239PuO2) at a concentration of 29.7 nanocuries per gram (nCi/g). In addition to alfalfa, radishes, wheat, rye, and tomatoes were grown in soils contaminated with americium-241 nitrate (241Am(NO3)3) at a concentration of 189 nCi/g. The length of exposure varied from 52 days for the radishes to 237 days for the alfalfa. The magnitude of plutonium incorporation by the alfalfa as indicated by the concentration ratio, 0.0000025, was similar to previously reported data using other chemical forms of plutonium. The results did indicate, however, that differences in the biological availability of plutonium isotopes do exist. All of the species exposed to americium-241 assimilated and translocated this radioisotope to the stem, leaf, and fruiting structures. The magnitude of incorporation as signified by the concentration ratios varied from 0.00001 for the wheat grass to 0.0152 for the radishes. An increase in the uptake of americium also occurred as a function of time for four of the five plant species. Evidence indicates that the predominant factor in plutonium and americium uptake by plants may involve the chelation of these elements in soils by the action of compounds such as citric acid and/or other similar chelating agents released from plant roots

Leaching of rare earth elements from bentonite clay

OpenAIRE

van der Watt, J.G; Waanders, F.B

2012-01-01

Due to increasing concerns of global rare earth element shortfalls in the near future, possible alternative sources of rare earth elements have recently become of economic interest. One such alternative is decanting acid mine water originating primarily from abandoned old mines in the Witwatersrand region of the Republic of South Africa. In this study, a novel way of rare earth element removal from the acid mine drainage was employed, making use of bentonite clay, which has very good adsorben...

Uptake and effects of americium-241 on a brackish-water amphipod

Energy Technology Data Exchange (ETDEWEB)

Hoppenheit, M.; Murray, C.N.; Woodhead, D.S.

1980-01-01

The present paper reports the results of experimental work undertaken using the brackish-water amphipod Gammarus duebeni duebeni and the transuranium nuclide americium-241. Data on the accumulation of this actinide showed that the larger fraction of the total body burden is associated with the exoskeleton. It was found that the body burden remained constant in the range pH 8.0-6.5 even though the water concentration changed markedly. It would thus appear that the concept of a concentration factor should be re-examined and it is proposed that a factor should be defined in terms of environmental and chemical parameters which represent the bioavailable fraction of the actinide. The effect of americium on survival and moulting was studied at two activity concentrations; the dose rates and absorbed doses under the experimental conditions employed have been estimated. The differences in survival rates between the control and irradiated groups were statistically analyzed and the significant difference at the higher concentration is believed to be due to a synergism between physiological stress and radiotoxicity of americium rather than the chemical toxicity of the element.

Uptake and effects of americium-241 on a brackish-water amphipod

International Nuclear Information System (INIS)

Hoppenheit, M.; Murray, C.N.; Woodhead, D.S.

1980-01-01

The present paper reports the results of experimental work undertaken using the brackish-water amphipod Gammarus duebeni duebeni and the transuranium nuclide americium-241. Data on the accumulation of this actinide showed that the larger fraction of the total body burden is associated with the exoskeleton. It was found that the body burden remained constant in the range pH 8.0-6.5 even though the water concentration changed markedly. It would thus appear that the concept of a concentration factor should be re-examined and it is proposed that a factor should be defined in terms of environmental and chemical parameters which represent the bioavailable fraction of the actinide. The effect of americium on survival and moulting was studied at two activity concentrations; the dose rates and absorbed doses under the experimental conditions employed have been estimated. The differences in survival rates between the control and irradiated groups were statistically analyzed and the significant difference at the higher concentration is believed to be due to a synergism between physiological stress and radiotoxicity of americium rather than the chemical toxicity of the element. (orig.) [de

On the structure of thorium and americium adenosine triphosphate complexes

International Nuclear Information System (INIS)

Mostapha, Sarah; Berton, Laurence; Boubals, Nathalie; Zorz, Nicole; Charbonnel, Marie-Christine; Fontaine-Vive, Fabien; Den Auwer, Christophe; Solari, Pier Lorenzo

2014-01-01

The actinides are chemical poisons and radiological hazards. One challenge to better appraise their toxicity and develop countermeasures in case of exposure of living organisms is to better assess pathways of contamination. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, nucleotides and in particular adenosine triphosphate nucleotide (ATP) may be considered critical target building blocks for actinides. Combinations of spectroscopic techniques (Fourier transformed Infra Red [FTIR], Electro-spray Ionization Mass Spectrometry [ESI-MS], and Extended X-ray Absorption Fine Structure [EXAFS]) with quantum chemical calculations have been implemented in order to assess the actinides coordination arrangement with ATP. We describe and compare herein the interaction of ATP with thorium and americium; thorium(IV) as a representative of actinide(IV) like plutonium(IV) and americium(III) as a representative of all heavier actinides. In the case of thorium, an insoluble complex is readily formed. In the case of americium, a behavior identical to that described previously for lutetium has been observed with insoluble and soluble complexes. The comparative study of ATP complexation with Th(IV) and Am(III) shows their ability to form insoluble complexes for which a structural model has been proposed by analogy with previously described Lu(III) complexes. (authors)

On the structure of thorium and americium adenosine triphosphate complexes.

Science.gov (United States)

Mostapha, Sarah; Fontaine-Vive, Fabien; Berthon, Laurence; Boubals, Nathalie; Zorz, Nicole; Solari, Pier Lorenzo; Charbonnel, Marie Christine; Den Auwer, Christophe

2014-11-01

The actinides are chemical poisons and radiological hazards. One challenge to better appraise their toxicity and develop countermeasures in case of exposure of living organisms is to better assess pathways of contamination. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, nucleotides and in particular adenosine triphosphate nucleotide (ATP) may be considered critical target building blocks for actinides. Combinations of spectroscopic techniques (Fourier transformed Infra Red [FTIR], Electrospray Ionization Mass Spectrometry [ESI-MS], and Extended X-ray Absorption Fine Structure [EXAFS]) with quantum chemical calculations have been implemented in order to assess the actinides coordination arrangement with ATP. We describe and compare herein the interaction of ATP with thorium and americium; thorium(IV) as a representative of actinide(IV) like plutonium(IV) and americium(III) as a representative of all heavier actinides. In the case of thorium, an insoluble complex is readily formed. In the case of americium, a behavior identical to that described previously for lutetium has been observed with insoluble and soluble complexes. The comparative study of ATP complexation with Th(IV) and Am(III) shows their ability to form insoluble complexes for which a structural model has been proposed by analogy with previously described Lu(III) complexes.

Structural characterisations and mechanistic investigations of the selective dissolution of americium by the ferricyanide ions in alkaline media. Application for the partitioning americium curium

International Nuclear Information System (INIS)

Fouchard, Sebastien

2000-01-01

Americium exhibits a high solubility form in basic media under oxidant conditions, unlike the other Transplutonium elements (TPE). This property can be used in the frame of High Level Liquid Waste (HLLW) treatment in order to extract preferentially the americium element, the main responsible of the long term radiotoxicity of the nuclear waste. This soluble compound can be obtained by addition of a concentrated basic solution of Fe(CN) 6 3- ions on Am(OH) 3 precipitates. This technique enables a rapid extraction of Am by the synthesis of this soluble form in alkaline solutions. Under these conditions, the other TPE remain in the solid state as trivalent hydroxide solids, strongly insoluble. In the case of dissolutions involving large amounts of Am(OH) 3 , the formation of the soluble complex is concomitant with the appearance of a reddish precipitate in the basic solution. Dissolution experiments which were carried out on this solid in NaOH/Fe(CN) 6 3- have demonstrated the dependency of the solubility equilibria with the media. Spectroscopic studies (UV Visible, XAS) on the precipitate have enabled the determination of the chemical structure and the oxidation state of the americium in the solid: Na 2 Am(V)O 2 (OH) 3 ,nH 2 O. Electrochemical studies on the americium solution have confirmed that the oxidation of Am(OH) 3 by the Fe(CN) 6 3- ions in basic media could only lead to the pentavalent form. A stoichiometric study carries out between a AmO 2 + ion and one Fe(CN) 6 3- ion and the spectroscopic characterisation of this reaction have demonstrated that the Fe(CN) 6 3- ion didn't remain as an un-complexed form in solution after the alkaline mixing. These results tend to prove that this dissolution of Am(OH) 3 is much more complex than a simple oxidation by the Fe(CN) 6 3- ions. The existence of molecular interactions between AmO 2 + and Fe(CN) 6 3- has been postulated and a mechanistic scheme has been proposed in order to explain the appearance of the soluble

Americium removal from nitric acid waste streams

International Nuclear Information System (INIS)

Muscatello, A.C.; Navratil, J.D.

1986-01-01

Separations research at the Rocky Flats Plant (RFP) has found ways to significantly improve americium removal from nitric acid (7M) waste streams generated by plutonium purification operations. Partial neutralization of the acid waste followed by solid supported liquid membranes (SLM) are useful in transferring and concentrating americium from nitrate solutions. Specifically, DHDECMP (dihexyl-N,N-diethylcarbamoylmethylphosphonate) supported on Accurel polypropylene hollow fibers assembled in modular form transfers >95% of the americium from high nitrate (6.9M), low acid (0.1M) feeds into 0.25M oxalic acid stripping solution. Maximum permeabilities were observed to be 0.001 cm/sec, consistent with typical values for other systems. The feed:strip volume ratio shows an inverse relationship to the fraction of metal ion transferred. Cation exchangers may be used to concentrate americium from the strip solution. Furthermore, O0D (iB)CMPO (or CMPO) (octylphenyl-N-N-diisobutylcarbamoylmethylphosphine oxide) has been tested in an extraction chromatography mode. Preliminary results show CMPO to be effective in removing americium if the feed is neutralized to 1.0M acidity and iron(III) is complexed with 0.20M oxalic acid. 3 figs

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.

Use of fluoride systems for some fission product separation from residues of fast reactor spent fuel fluorination

International Nuclear Information System (INIS)

Shishkov, Yu.D.; Khomyakov, V.I.

1977-01-01

Investigated has been a possibility of the use of fluoride systems (acid nitrozyl fluoride and molten salts) for americium extraction from residues of fluorination of irradiated fuel containing mainly fluorides of rare earth compounds, alkali and alkaline earth elements. At treatment of fission product fluorides by acid nitrozyl fluoride only cesium and uranium fluorides dissolve, while americium and rare earth fluorides are practically non-soluble in it. The solubility of cesium, strontium, barium and fluorides of some other rare earth elements in molten cryolite at the temperature of 1000 deg C, Li-NaF and LiF-CaF 2 of eutectic content at 750 and 800 deg C are respectively 15-77 %. Cerium fluoride presents an exception, its solubility in cryolite being only 0.73%. At treatment of mixture of americium and lanthanum fluorides by molten salts in the weight ratio of 1:1, approximately 50% of lanthanum and 65-70% of americium turn into melt independent of the type of melt. The maximum melt output of americium is obtained at treatment of lanthanum and americium fluoride mixture by cryolite melt at the temperature of 1000 deg C. It is shown that the presence of rare earth of fluorides, except lanthanum fluoride, effect significantly of americium distribution over phases in the process of fluoride processing by the fluoride molten salts

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)

Aqueous Chloride Operations Overview: Plutonium and Americium Purification/Recovery

Energy Technology Data Exchange (ETDEWEB)

Kimball, David Bryan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Skidmore, Bradley Evan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-06-22

Acqueous Chloride mission is to recover plutonium and americium from pyrochemical residues (undesirable form for utilization and storage) and generate plutonium oxide and americium oxide. Plutonium oxide is recycled into Pu metal production flowsheet. It is suitable for storage. Americium oxide is a valuable product, sold through the DOE-OS isotope sales program.

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

Biosorption of americium by alginate beads

International Nuclear Information System (INIS)

Borba, Tania Regina de; Marumo, Julio Takehiro; Goes, Marcos Maciel de; Ferreira, Rafael Vicente de Padua; Sakata, Solange Kazumi

2009-01-01

The use of biotechnology to remove heavy metals from wastes plays great potential in treatment of radioactive wastes and therefore the aim of this study was to evaluate the biosorption of americium by alginate beads. Biosorption has been defined as the property of certain biomolecules to bind and remove selected ions or other molecules from aqueous solutions. The calcium alginate beads as biosorbent were prepared and analyzed for americium uptaking. The experiments were performed in different solution activity concentrations, pH and exposure time. The results suggest that biosorption process is more efficient at pH 4 and for 75, 150, 300 Bq/mL and 120 minutes were necessary to remove almost 100% of the americium-241 from the solution. (author)

Americium product solidification and disposal

International Nuclear Information System (INIS)

Mailen, J.C.; Campbell, D.O.; Bell, J.T.; Collins, E.D.

1987-01-01

The americium product from the TRUEX processing plant needs to be converted into a form suitable for ultimate disposal. An evaluation of the disposal based on safety, number of process steps, demonstrated operability of the processes, production of low-level alpha waste streams, and simplicity of maintenance with low radiation exposures to personnel during maintenance, has been made. The best process is to load the americium on a cation exchange resin followed by calcination or oxidation of the resin after loading

Recovery of trans-plutonium elements; Recuperation des elements transplutoniens

Energy Technology Data Exchange (ETDEWEB)

Espie, J Y; Poncet, B; Simon, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1970-07-01

The object of this work is to study the recovery of americium and curium from the fission-product solution obtained from the processing of irradiated fuel elements made of natural metallic uranium alloyed with aluminium, iron and silicon; these elements have been subjected to an average irradiation of 4000 MW days/ton in a gas-graphite type reactor having a thermal power of 3.7 MW/ton of uranium. The process used consists of 3 extraction cycles and one americium-curium separation: - 1) extraction cycle in 40 per cent TBP: extraction of actinides and lanthanides; elimination of fission products; - 2) extraction cycle in 8 per cent D2EHPA: decontamination from the fission products, decontamination of actinides from lanthanides; - 3) extraction cycle in 40 per cent TBP: separation of the complexing agent and concentration of the actinides; - 4) americium-curium separation by precipitation. (authors) [French] Cette etude a pour objet, la recuperation de l'americium et du curium de la solution de produits de fission provenant du traitement de combustibles irradies a base d'uranium naturel metallique allie a l'aluminium, le fer, et le silicium, et ayant subi une irradiation moyenne de 4000 MWj/t dans une pile du type graphite-gaz, dont la puissance thermique est de 3.7 MW/t d'uranium. Le procede utilise comprend 3 cycles d'extraction et une separation americium-curium: - 1. cycle d'extraction dans le TBP a 40 pour cent: extraction des actinides et des lanthanides, elimination des produits de fission; - 2. cycle d'extraction dans le D2EHPA a 8 pour cent: decontamination en produits de fission, decontamination des actinides en lanthanides; - 3. cycle d'extraction dans le TBP a 40 pour cent: separation du complexant et concentration des actinides; - 4. separation americium-curium par precipitation. (auteurs)

Americium-241 radioisotope thermoelectric generator development for space applications

International Nuclear Information System (INIS)

Ambrosi, Richard; Williams, Hugo; Samara-Ratna, Piyal

2013-01-01

Space nuclear power systems are under development in the UK in collaboration with European partners as part of a European Space Agency (ESA) programme. Radioisotope thermoelectric generators (RTG) are an important element of this new capability in Europe. RTG systems being developed in Europe are targeting the 10 W electric to 50 W electric power generation range adopting a modular scalable approach to the design. Radiogenic decay heat from radioisotopes can be converted to electrical power by using appropriate semiconductor based thermoelectric materials. The plan for Europe is to develop radioisotope space nuclear power systems based on both thermoelectric and Stirling power conversion systems. Although primarily focused on delivering up to 50 W of electrical power, the European radioisotope thermoelectric system development programme is targeting americium-241 as a fuel source and is maximizing the use of commercially available thermoelectric manufacturing processes in order to accelerate the development of power conversion systems. The use of americium provides an economic solution at high isotopic purity and is product of a separation process from stored plutonium produced during the reprocessing of civil nuclear fuel. A laboratory prototype that uses electrical heating as a substitute for the radioisotope was developed to validate the designs. This prototype has now been tested. This paper outlines the requirements for a European americium-241 fuelled RTG, describes the most recent updates in system design and provides further insight into recent laboratory prototype test campaigns. (author)

Americium-241 radioisotope thermoelectric generator development for space applications

Energy Technology Data Exchange (ETDEWEB)

Ambrosi, Richard; Williams, Hugo; Samara-Ratna, Piyal, E-mail: rma8@le.ac.uk [University of Leicester, (United Kingdom); and others

2013-07-01

Space nuclear power systems are under development in the UK in collaboration with European partners as part of a European Space Agency (ESA) programme. Radioisotope thermoelectric generators (RTG) are an important element of this new capability in Europe. RTG systems being developed in Europe are targeting the 10 W electric to 50 W electric power generation range adopting a modular scalable approach to the design. Radiogenic decay heat from radioisotopes can be converted to electrical power by using appropriate semiconductor based thermoelectric materials. The plan for Europe is to develop radioisotope space nuclear power systems based on both thermoelectric and Stirling power conversion systems. Although primarily focused on delivering up to 50 W of electrical power, the European radioisotope thermoelectric system development programme is targeting americium-241 as a fuel source and is maximizing the use of commercially available thermoelectric manufacturing processes in order to accelerate the development of power conversion systems. The use of americium provides an economic solution at high isotopic purity and is product of a separation process from stored plutonium produced during the reprocessing of civil nuclear fuel. A laboratory prototype that uses electrical heating as a substitute for the radioisotope was developed to validate the designs. This prototype has now been tested. This paper outlines the requirements for a European americium-241 fuelled RTG, describes the most recent updates in system design and provides further insight into recent laboratory prototype test campaigns. (author)

MaRGEE: Move and Rotate Google Earth Elements

Science.gov (United States)

Dordevic, Mladen M.; Whitmeyer, Steven J.

2015-12-01

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

Americium migration in basalt and implications to repository risk analysis

International Nuclear Information System (INIS)

Rickert, P.G.

1980-01-01

Experiments were performed with americium as a minor component in groundwater. Batch adsorption, migration through column, and filtration experiments were performed. It was determined in batch experiments that americium is strongly adsorbed from solution. It was determined with filtration experiments that large percentages of the americium concentrations suspended by the contact solutions in batch experiments and suspended by the infiltrating groundwater in migration experiments were associated with particulate. Filtration was determined to be the primary mode of removal of americium from infiltrating groundwater in a column of granulated basalt (20 to 50 mesh) and an intact core of permeable basalt. Fractionally, 0.46 and 0.22 of the americium component in the infiltrating groundwater was transported through the column and core respectively. In view of these filtration and migration experiment results, the concept of K/sub d/ in the chromatographic sense is meaningless for predicting americium migration in bedrock by groundwater transport at near neutral pH

Remobilization of americium in soil columns under experimental rhizo-spheric conditions

Energy Technology Data Exchange (ETDEWEB)

Perrier, T.; Martin-Garin, A.; Morello, M. [CEA Cadarache (DEI/SECRE/LRE), Laboratory of Radioecology and Ecotoxicology, Institute for Radioprotection and Nuclear Safety, 13 - Saint-Paul-lez-Durance (France)

2004-07-01

The biogeochemical behaviour of americium in subsurface soils plays a dominant role on the potential migration of this actinide, but is currently poorly known. The identification and understanding of these processes is of major concern for this highly (radio)toxic element and can allow the determination of its impact on the natural media. This research investigates the relevant processes controlling americium biogeochemical speciation in the rhizosphere of an agricultural soil. Lixiviation tests were performed on columns packed with a 2 mm-sieved calcareous soil contaminated with {sup 241}Am (500 Bq.g{sup -1}), under steady-state unsaturated or saturated hydric flow conditions. The columns were percolated with soil solution of varied compositions, containing citrate and/or glucose simulating root exudates in non-sterile conditions. The physico-chemical parameters of the outlet solution (pH, conductivity, major ions, organic acids) were monitored, as well as the microbial activity. Inorganic and organic speciation of {sup 241}Am is supported by geochemical modeling with JChess, using a thermodynamic database based on NEA database and the latest PSI recommendations. The percolation of a solution in equilibrium with the soil released small amount of americium (<5 mBq/cm{sup 3}), as predicted by the high {sup 241}Am K{sub d} values. 10{sup -4} M concentrations of citrate, glucose or both combined did not enhance remobilization either. Poor remobilization was also observed at high glucose concentrations (10{sup -2} M), despite an effective glucose microbial degradation, the production of ligands such as acetate, and important changes in the chemistry of the solution. On the contrary, high concentrations of citrate (10{sup -2} M) released 1000 times more americium, which is in accordance with previous studies. Even greater releases (10000 times) were observed when 10{sup -2} M glucose was added to 10{sup -2} M citrate. The remobilization of americium resulting from the

Experimental and in situ investigations on americium, curium and plutonium behaviour in marine benthic species: transfer from water or sediments

International Nuclear Information System (INIS)

Miramand, P.

1984-06-01

The tranfer of transuranic elements -americium, curium and plutonium- from the sediments containing them to some marine benthic species (endofauna and epifauna) was studied with a twofold approach - laboratory and in-situ investigation. The experimental investigations, divided into three parts, made it possible to specify concentration factors (F.C.), transfer factors (F.T.) and to understand the process involved for 5 benthic species. The result were refined by an in-situ study that brought new data on the marine distribution of the transuranic elements released by the La Hague plant. Finally, the localization of americium and plutonium in the tissues and cells of these species was determined by autoradiography [fr

Incorporation of transuranic elements in titanate nuclear waste ceramics

International Nuclear Information System (INIS)

Matzke, H.J.; Ray, I.L.F.; Theile, H.; Trisoglio, C.; Walker, C.T.; White, T.J.

1990-01-01

The incorporation of actinide elements and their rare-earth element analogues in titanate nuclear waste forms in reviewed. New partitioning data are presented for three waste forms containing Purex waste simulant in combination with either NpO 2 , PuO 2 , or Am 2 O 3 . The greater proportion of transuranics partition between perovskite and zirconolite, while some americium may enter loveringite. Autoradiography revealed clusters of plutonium atoms which have been interpreted as unreacted dioxide or sesquioxide. It is concluded that the solid-state behavior of transuranic elements in titanate waste forms is poorly understood, certainly not well enough to tailor a ceramic for the incorporation of waste from reprocessing of fast breeder reactor fuel in which transuranic species are more abundant than in Purex waste

Rare earth element abundances and distribution patterns in plant materials

International Nuclear Information System (INIS)

Aidid, S.B.

1994-01-01

Eight out of the fourteen rare earth elements were estimated from the leaves of Pelthophorum pterocarpum, the leaves and roots of Impatiens balsamina, and the soils from four sampling sites by instrumental neutron activation analysis. The chondrite normalized rare earth element abundances and distribution patterns in the plant materials were found to be significantly correlated to the abundances of the rare earth elements occurring in the soils. The extent of accumulation of the rare earth elements in some plant materials was also governed by the age of the plants and the plant organs. (author) 16 refs.; 4 figs.; 3 tabs

Speciation and bioavailability of plutonium and americium in the Irish Sea and other marine ecosystems

International Nuclear Information System (INIS)

Vives i Batlle, J.

1993-12-01

Since the late 1960s, the Irish Sea has become a repository for a variety of radio-elements originating mainly in discharges from the British Nuclear Fuels (BNF) plc. Sellafield reprocessing complex located on the Cumbrian coast. In particular, transuranium nuclides such as plutonium, americium and curium (the main constituents of the α-emitting discharges) have become incorporated into every marine compartment by a variety of mechanisms, many of which are not well understood. Although extensive studies have been carried out in the near-field (eastern Irish Sea, especially in the vicinity of the discharge point and collateral muddy sediments), comparatively little had been done to assess the long-term behaviour and bioavailability of plutonium and americium in the far-field, e.g., the western Irish Sea, prior to the present study. In this dissertation, the results of an extensive research programme, undertaken in order to improve and refine our understanding of the behaviour of plutonium and americium in the marine environment, are presented. Specifically, the thesis details the results of (and conclusions deduced from) a series of experiments in which the physical and chemical speciation, colloidal association, mobility and bioavailability of plutonium and americium were examined in diverse environments including the Irish Sea and the Mediterranean. (author)

Transmutation of Americium in Fast Neutron Facilities

International Nuclear Information System (INIS)

Zhang, Youpeng

2011-01-01

In this thesis, the feasibility to use a medium sized sodium cooled fast reactor fully loaded with MOX fuel for efficient transmutation of americium is investigated by simulating the safety performance of a BN600-type fast reactor loaded with different fractions of americium in the fuel, using the safety parameters obtained with the SERPENT Monte Carlo code. The focus is on americium mainly due to its long-term contribution to the radiotoxicity of spent nuclear fuel and its deterioration on core's safety parameters. Applying the SAS4A/SASSYS transient analysis code, it is demonstrated that the power rating needs to be reduced by 6% for each percent additional americium introduction into the reference MOX fuel, maintaining 100 K margin to fuel melting, which is the most limiting failure mechanism. Safety analysis of a new Accelerator Driven System design with a smaller pin pitch-to-diameter ratio comparing to the reference EFIT-400 design, aiming at improving neutron source efficiency, was also performed by simulating performance for unprotected loss of flow, unprotected transient overpower, and protected loss-of-heat-sink transients, using neutronic parameters obtained from MCNP calculations. Thanks to the introduction of the austenitic 15/15Ti stainless steel with enhanced creep rupture resistance and acceptable irradiation swelling rate, the suggested ADS design loaded with nitride fuel and cooled by lead-bismuth eutectic could survive the full set of transients, preserving a margin of 130 K to cladding rupture during the most limiting transient. The thesis concludes that efficient transmutation of americium in a medium sized sodium cooled fast reactor loaded with MOX fuel is possible but leads to a severe power penalty. Instead, preserving transmutation rates of minor actinides up to 42 kg/TWh th , the suggested ADS design with enhanced proton source efficiency appears like a better option for americium transmutation

Citric complexes, neodymium citrate and americium citrate

International Nuclear Information System (INIS)

Bouhlassa, Saidati.

1981-06-01

The behaviour of neodymium and americium has been studied in citric aqueous medium by two methods: solvent extraction of elements at tracer scale as chelates and by potentiometry. So range of pH and concentrations of elements and citric acid never reached before have been explored: 10 -7 -1 M, 10 -10 -3 , Csub(H3 Cit) -1 M, 1 2 O; AmCit, xH 2 O; NdCit 2 Co(NH 3 ) 6 , 8H 2 O; AmCit 2 Co(NH 3 ) 6 , xH 2 O and Nd 3 (OH) 4 (Cit) 4 NH 4 (Co(NH 3 ) 6 ) 2 , 18H 2 O. Their spectroscopic and crystallographic characteristics have been listed and studied. The nephelauxetic effect has been estimated from citric complexes as well as from citrates of these elements. The structure of the complexes in solution has been discussed on the basis of analysis of hypersensitive transition in different complexes [fr

Preparation of americium metal of high purity and determination of the heat of formation of the hydrated trivalent americium ion

International Nuclear Information System (INIS)

Spirlet, J.C.

1975-10-01

In order to redetermine some physical and chemical properties of americium metal, several grams of Am-241 have been prepared by two independent methods: lanthanum reduction of the oxide and thermal dissociation of the intermetallic compound Pt 5 Am. After its separation from excess lanthanum or alloy constituent by evaporation, americium metal was further purified by sublimation at 1100 deg C and 10 -6 Torr. Irrespective of the method of preparation, the americium samples displayed the same d.h.c.p. crystal structure. As determined by vacuum hot extraction, the oxygen, nitrogen and hydrogen contents are equal to or smaller than 250, 50 and 20 ppm, respectively. The heats of solution of americium metal (d.c.h.p. structure) in aqueous hydrochloric acid solutions have been measured at 298.15+-0.05K. The standard enthalpy of formation of Am 3+ (aq) is obtained as -616.7+-1.2 kJ mol -1 [fr

Calibration procedures for in vivo sodium iodide spectrometry of plutonium and americium in the human lung

International Nuclear Information System (INIS)

Umbarger, C.J.; Jett, J.H.

1976-01-01

This paper describes the calibration techniques and associated error analysis for the in vivo measurement by NaI spectrometry of heavy elements in the lung, specifically plutonium and americium. A very brief description of the instrumentation system is included

Transplutonium elements

Energy Technology Data Exchange (ETDEWEB)

Sivaramakrishnan, C. K.; Jadhav, A. V.; Reghuraman, K.; Mathew, K. A.; Nair, P. S.; Ramaniah, M. V.

1973-07-01

Research progress is reported on studies of the transplutonium elements including recovery and purification of americium, preparation of /sup 238/Pu, extraction studies using diethylhexyl phosphate. (DHM)

Chemistry of americium

Energy Technology Data Exchange (ETDEWEB)

Schulz, W.W.

1976-01-01

Essential features of the descriptive chemistry of americium are reviewed. Chapter titles are: discovery, atomic and nuclear properties, collateral reading, production and uses, chemistry in aqueous solution, metal, alloys, and compounds, and, recovery, separation, purification. Author and subject indexes are included. (JCB)

Study of the extraction and the purification of americium and trivalent actinides contained in effluents with supported liquid membranes

International Nuclear Information System (INIS)

Guillou, P.

1990-12-01

The supported liquid membrane technique is studied and developed for americium recovery from uranium or plutonium matrices and decontamination of liquid radioactive wastes. First tests on uranium-nickel solutions with a flat membrane showed the easiness of the operation and the efficiency of the process. Acid-resistant (10 N), interchangeable elements with hollow fibers, are developed and also a computerized automatic device. The different tests on americium solutions demonstrate the feasibility and the reliability of the system. Influence of various parameters on transfer kinetics is investigated

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.

General geochemical properties and abundances of the rare earth elements

International Nuclear Information System (INIS)

Henderson, P.

1984-01-01

This chapter reviews some of the fundamental aspects of rare earth elements (REE) geochemistry and gives data on abundances in the solar system, the bulk Earth and the Earth's crust. It describes the state of knowledge on the partitioning of the REE, especially in igneous rock systems, and cites reference works concerned with the REE. Several chemical properties of REE are discussed (oxidation states; redox conditions; element coordination and ionic radii; element substitution). (Auth.)

Membrane assisted solvent extraction for rare earth element recovery

Science.gov (United States)

Bhave, Ramesh R.; Kim, Daejin; Peterson, Eric S.

2018-05-15

Systems and methods for the recovery of rare earth elements are provided. The systems and methods generally include membrane assisted solvent extraction using permeable hollow fibers having an immobilized organic phase within the pores of the hollow fibers. The permeable hollow fibers are generally in contact with an acidic aqueous feed on one side thereof and a strip solution on another side thereof. The systems and methods generally include the simultaneous extraction and stripping of rare earth elements as a continuous recovery process that is well suited for post-consumer products, end-of-life products, and other recovery sources of rare earth elements.

Electric resistivity of 241-americium and 244-curium metals. Creation of defects and isochronous annealing of 241-americium metal after self-irradiation

International Nuclear Information System (INIS)

Schenkel, R.

1977-03-01

The temperature dependence of the electrical resistivity of thin films of bulk 241 Am metal were measured between 300 and 4.5 K. The room temperature resistivity was found to be 68.90μΩcm. At room temperature the electrical resistivity of americium increases with pressure (3% up to 13 kbar). The application of 13 kbar pressure did not change the low temperature power law in the electrical resistivity. The resistivity vs temperature curve can be explained by assuming s-d scattering of conduction electrons. The localized 5f electrons are considered to be about 5eV below the Fermi level. Americium therefore should be the first lanthanide-like element in the actinide series. The defect production due to self-irradiation damage was studied by measuring the increase of the resistivity at 4.2 K over a period of 738 h. A saturation resistivity of 16.036 μΩcm was found corresponding to a defect concentration of about 0.22 a/o. After isochronal annealing two recovery stages were observed at about 65 and 145 K. The two stages shift with increasing initial defect concentration to lower temperatures. Estimates of the activation energies and the reaction order were made and possible defect reactions suggested. The magnetic contribution to the electrical resistivity of curium, which shows an antiferromagnetic transition at 52.5 k, was obtained by subtracting the resistivity of americium (to be considered as phonon part). Comparison with theoretical models were made. At low temperatures the measurements are strongly affected by self-irradiation damage [drho/dt(t=0)=9.8μΩcm/h

Formation of americium and europium humate complexes

International Nuclear Information System (INIS)

Minai, Y.; Tominaga, T.; Meguro, Y.

1991-01-01

Binding constants of americium and europium with a humic acid were determined to study if complex formation of trivalent actinide-humates affects dissolved species of the actinides in hydrosphere. The purified humic acid was characterized by means of UV-vis, IR, and pH titration, indicating high carboxylate capacity and low aromaticity. Binding constants of americium and europium humates were determined at pH 4.6 and 6.0 by solvent extraction using 241 Am or 152 Eu as a tracer. The binding constants for americium-humate obtained preliminarily suggest that complexes with humic acid are not negligible in speciation of trivalent actinides in hydrosphere. The obtained binding constants were nearly identical with those determined previously by the same procedures, but with humic acids of different origin and compositions. (author)

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

Science.gov (United States)

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

2011-01-01

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

Plutonium and Americium Geochemistry at Hanford: A Site Wide Review

Energy Technology Data Exchange (ETDEWEB)

Cantrell, Kirk J.; Felmy, Andrew R.

2012-08-23

This report was produced to provide a systematic review of the state-of-knowledge of plutonium and americium geochemistry at the Hanford Site. The report integrates existing knowledge of the subsurface migration behavior of plutonium and americium at the Hanford Site with available information in the scientific literature regarding the geochemistry of plutonium and americium in systems that are environmentally relevant to the Hanford Site. As a part of the report, key research needs are identified and prioritized, with the ultimate goal of developing a science-based capability to quantitatively assess risk at sites contaminated with plutonium and americium at the Hanford Site and the impact of remediation technologies and closure strategies.

Investigation of factors affecting the quality of americium electroplating

International Nuclear Information System (INIS)

Trdin, M.; Benedik, L.; Samardžija, Z.; Pihlar, B.

2012-01-01

Four different electrolyte solutions were used in the electrodeposition of americium and their influences on the quality of the thin layer of deposited americium isotopes in combination with three different cathode disc materials were investigated. The relations between alpha spectral resolution and disc surface properties were established. - Highlights: ► Compared alpha spectra of americium radioisotopes obtained by electrodeposition. ► Various cathode materials and electrolyte solutions were used. ► Homogeneity and peak area resolution were investigated. ► Electron microscope images show surface structure of electrodeposited material.

Measurement of plutonium and americium in molten salt residues

International Nuclear Information System (INIS)

Haas, F.X.; Lawless, J.L.; Herren, W.E.; Hughes, M.E.

1979-01-01

The measurement of plutonium and americium in molten salt residues using a segmented gamma-ray scanning device is described. This system was calibrated using artificially fabricated as well as process generated samples. All samples were calorimetered and the americium to plutonium content of the samples determined by gamma-ray spectroscopy. For the nine samples calorimetered thus far, no significant biases are present in the comparison of the segmented gamma-ray assay and the calorimetric assay. Estimated errors are of the order of 10 percent and is dependent on the americium to plutonium ratio determination

Americium separations from high salt solutions

International Nuclear Information System (INIS)

Barr, Mary E.; Jarvinen, Gordon D.; Schulte, Louis D.; Stark, Peter C.; Chamberlin, Rebecca M.; Abney, Kent D.; Ricketts, Thomas E.; Valdez, Yvette E.; Bartsch, Richard A.

2000-01-01

Americium (III) exhibits an unexpectedly high affinity for anion-exchange material from the high-salt evaporator bottoms solutions--an effect which has not been duplicated using simple salt solutions. Similar behavior is observed for its lanthanide homologue, Nd(III), in complex evaporator bottoms surrogate solutions. There appears to be no single controlling factor--acid concentration, total nitrate concentration or solution ionic strength--which accounts for the approximately 2-fold increase in retention of the trivalent ions from complex solutions relative to simple solutions. Calculation of species activities (i.e., water, proton and nitrate) in such concentrated mixed salt solutions is difficult and of questionable accuracy, but it is likely that the answer to forcing formation of anionic nitrate complexes of americium lies in the relative activities of water and nitrate. From a practical viewpoint, the modest americium removal needs (ca. 50--75%) from nitric acid evaporator bottoms allow sufficient latitude for the use of non-optimized conditions such as running existing columns filled with older, well-used Reillex HPQ. Newer materials, such as HPQ-100 and the experimental bifunctional resins, which exhibit higher distribution coefficients, would allow for either increased Am removal or the use of smaller columns. It is also of interest that one of the experimental neutral-donor solid-support extractants, DHDECMP, exhibits a similarly high level of americium (total alpha) removal from EV bottoms and is much less sensitive to total acid content than commercially-available material

Transmutation of americium in critical reactors

International Nuclear Information System (INIS)

Wallenius, J.

2005-01-01

Already in 1974, a Los Alamos report suggested that the recycling of higher actinides would be detrimental for the safety of critical reactors. Later investigations confirmed this understanding, and stringent limits on the fraction of minor actinides allowed to be present in the fuel of fast neutron reactors were established. In recent years, and in particular in connection with the generation IV initiative, it has been advocated that recycling of americium in critical reactors is not only feasible, but also a recommendable approach. In the present contribution, it is shown, to the contrary, that introduction of americium into reactors with uranium based fuels deteriorates the safety margin of these reactors to a degree that will not allow consumption of the americium sources present in any economically competitive nuclear fuel cycle. Further, it is shown that uranium and thorium free cores with plutonium based fuels may be designed, that features excellent safety characteristics, as long as americium is not present in the feed. Hence, a closed fuel cycle is suggested, that consists of commercial power production in light water reactors, plutonium burning in uranium and thorium free fast neutron critical reactors, and higher actinide consumption in accelerator driven systems with inert matrix fuel. It is argued that such a fuel cycle (being a refinement of the Double Strata fuel cycle proposed by JAERI and further developed by M. Salvatores) provides a minimum cost penalty for implementing P and T under realistic boundary conditions. (author)

Coprecipitation of rare earth elements with hydroxyapatite

International Nuclear Information System (INIS)

Fujino, Osamu

1979-01-01

The distribution behavior of trace rare earth elements between an aqueous phase and hydroxyapatite crystals was investigated. The apatite prepared by adding phosphate ion extremely slowly to an aqueous solution containing calcium, rare earth elements, ethylenediamine and nitrilotriacetate ion at 80 0 C. Apparently the coprecipitation reaction seems to be anomalous, because the apparent distribution coefficient did not have a constant value through the reaction. But when the true distribution coefficient was calculated by using the thermodynamic data at 80 0 C, it was revealed that rare earth ions were coprecipitated obeying logarithmic distribution law. The true distribution coefficient values of trivalent yttrium, scandium, europium and cerium ions were about 10sup(7.3), 10sup(9.8), 10sup(7.4) and 10sup(6.5) respectively. (author)

Spectrofluorimetric determination of rare earth elements using solidmatrix

International Nuclear Information System (INIS)

Suh, I.S.; Chi, K.Y.

1982-01-01

In this experiment, rare earth elements are separated from uranium by using the alumina column, anion exchange resin column, and 20% TOA in xylene and fluorescence characteristics were found in the solid matrix to analyze these elements without preseparation from each other. It becomes clear that the YVO 4 matrix is more sensitive than the Y 2 O 3 matrix when the red filter is used to minimized the second order peak intensity. And micro quantity of the rare earth elements in the yellow cake are analyzed by the using of the YVO 4 soid matrix. (Author)

Sorption of americium and neptunium by deep-sea sediments

International Nuclear Information System (INIS)

Higgo, J.J.W.; Rees, L.V.C.; Cronan, D.S.

1983-01-01

The sorption and desorption of americium and neptunium by a wide range of deep-sea sediments from natural sea water at 4 0 C has been studied using a carefully controlled batch technique. All the sediments studied should form an excellent barrier to the migration of americium since distribution coefficients were uniformly greater than 10 5 and the sorption-desorption reaction may not be reversible. The sorption of neptunium was reversible and, except for one red clay, the distribution coefficients were greater than 10 3 for all the sediments investigated. Nevertheless the migration of neptunium should also be effectively retarded by most deep-sea sediments even under relatively oxidizing conditions. The neptunium in solution remained in the V oxidation state throughout the experiments. Under the experimental conditions used colloidal americium was trapped by the sediment and solubility did not seem to be the controlling factor in the desorption of americium. (Auth.)

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

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

Science.gov (United States)

Yang, Xiuli; Zhang, Junwei; Fang, Xihui

2014-08-30

With an increase in number of waste nickel-metal hydride batteries, and because of the importance of rare earth elements, the recycling of rare earth elements is becoming increasingly important. In this paper, we investigate the effects of temperature, hydrochloric acid concentration, and leaching time to optimize leaching conditions and determine leach kinetics. The results indicate that an increase in temperature, hydrochloric acid concentration, and leaching time enhance the leaching rate of rare earth elements. A maximum rare earth elements recovery of 95.16% was achieved at optimal leaching conditions of 70°C, solid/liquid ratio of 1:10, 20% hydrochloric acid concentration, -74μm particle size, and 100min leaching time. The experimental data were best fitted by a chemical reaction-controlled model. The activation energy was 43.98kJ/mol and the reaction order for hydrochloric acid concentration was 0.64. The kinetic equation for the leaching process was found to be: 1-(1-x)(1/3)=A/ρr0[HCl](0.64)exp-439,8008.314Tt. After leaching and filtration, by adding saturated oxalic solution to the filtrate, rare earth element oxalates were obtained. After removing impurities by adding ammonia, filtering, washing with dilute hydrochloric acid, and calcining at 810°C, a final product of 99% pure rare earth oxides was obtained. Copyright © 2014 Elsevier B.V. All rights reserved.

Supported extractant membranes for americium and plutonium recovery

International Nuclear Information System (INIS)

Muscatello, A.C.; Navratil, J.D.; Killion, M.E.; Price, M.Y.

1987-01-01

Solid supported liquid membranes(SLM) are useful in transferring and concentrating americium and plutonium from nitrate solutions. Specifically, DHDECMP(dihexyl-N,N-diethylcarbamoylmethylphosphonate) supported on Accurel or Celgard polypropylene hollow fibers assembled in modular form transfers >95% of the americium and >70% of the plutonium from high nitrate (6.9 M), low acid (0.1 M) feeds into 0.25 M oxalic acid stripping solution. Membranes supporting TBP (tri-n-butylphosphate) also transfer these metal ions. Maximum permeabilities were observed to be 1 x 10 -3 cm sec -1 , similar to the values for other systems. The feed:strip volume ratio shows an inverse relationship to the fraction of metal ion transferred. Cation exchangers may be used to concentrate americium from the strip solution

Game meat authentication through rare earth elements fingerprinting

International Nuclear Information System (INIS)

Danezis, G.P.; Pappas, A.C.; Zoidis, E.; Papadomichelakis, G.; Hadjigeorgiou, I.; Zhang, P.; Brusic, V.; Georgiou, C.A.

2017-01-01

Accurate labelling of meat (e.g. wild versus farmed, geographical and genetic origin, organic versus conventional, processing treatment) is important to inform the consumers about the products they buy. Meat and meat products declared as game have higher commercial value making them target to fraudulent labelling practices and replacement with non-game meat. We have developed and validated a new method for authentication of wild rabbit meat using elemental metabolomics approach. Elemental analysis was performed using rapid ultra-trace multi-element measurement by inductively coupled plasma mass spectrometry (ICP-MS). Elemental signatures showed excellent ability to discriminate the wild rabbit from non-wild rabbit meat. Our results demonstrate the usefulness of metabolic markers -rare earth signatures, as well as other trace element signatures for game meat authentication. - Highlights: • Elemental metabolomics is a powerful new methodology for authentication of game rabbit meat. • New method for meat authentication utilizing rare earths elemental signatures. • Samples are compared to group signatures using angular and Euclidean distances. • Meat reference materials (>70 elements) can be used for cross-comparison between studies.

Neutron activation analysis of the rare earth elements in Nasu hot springs

International Nuclear Information System (INIS)

Ikeda, Nagao; Takahashi, Naruto.

1978-01-01

Eleven rare earth elements (lanthanum, cerium, neodymium, samarium, europium, gadolinium, terbium, holmium, thulium, ytterbium and lutetium) in hot spring waters and sinter deposits in the Nasu area were determined by the neutron activation method. The rare earth elements in hot spring water were preconcentrated in ferric hydroxide precipitate and neutron-irradiated. The rare earth elements were chemically separated into lighter and heavier groups and the activity of each group was measured with a Ge(Li) detector. Distribution of the rare earth elements between the hot spring water and the sinter deposit was also discussed. (auth.)

Recovery of americium-241 from aged plutonium metal

International Nuclear Information System (INIS)

Gray, L.W.; Burney, G.A.; Reilly, T.A.; Wilson, T.W.; McKibben, J.M.

1980-12-01

About 5 kg of ingrown 241 Am was recovered from 850 kg of aged plutonium using a process developed specifically for Savannah River Plant application. The aged plutonium metal was first dissolved in sulfamic acid. Sodium nitrite was added to oxidize the plutonium to Pu(IV) and the residual sulfamate ion was oxidized to nitrogen gas and sulfate. The plutonium and americium were separated by one cycle of solvent extraction. The recovered products were subsequently purified by cation exchange chromatography, precipitated as oxalates, and calcined to the oxides. Plutonium processng was routine. Before cation exchange purification, the aqueous americium solution from solvent extraction was concentrated and stripped of nitric acid. More than 98% of the 241 Am was then recovered from the cation exchange column where it was effectively decontaminated from all major impurities except nickel and chromium. This partially purified product solution was concentrated further by evaporation and then denitrated by reaction with formic acid. Individual batches of americium oxalate were then precipitated, filtered, washed, and calcined. About 98.5% of the americium was recovered. The final product purity averaged 98% 241 AmO 2 ; residual impurities were primarily lead and nickel

Development of analytical methods for the separation of plutonium, americium, curium and neptunium from environmental samples

Energy Technology Data Exchange (ETDEWEB)

Salminen, S.

2009-07-01

In this work, separation methods have been developed for the analysis of anthropogenic transuranium elements plutonium, americium, curium and neptunium from environmental samples contaminated by global nuclear weapons testing and the Chernobyl accident. The analytical methods utilized in this study are based on extraction chromatography. Highly varying atmospheric plutonium isotope concentrations and activity ratios were found at both Kurchatov (Kazakhstan), near the former Semipalatinsk test site, and Sodankylae (Finland). The origin of plutonium is almost impossible to identify at Kurchatov, since hundreds of nuclear tests were performed at the Semipalatinsk test site. In Sodankylae, plutonium in the surface air originated from nuclear weapons testing, conducted mostly by USSR and USA before the sampling year 1963. The variation in americium, curium and neptunium concentrations was great as well in peat samples collected in southern and central Finland in 1986 immediately after the Chernobyl accident. The main source of transuranium contamination in peats was from global nuclear test fallout, although there are wide regional differences in the fraction of Chernobyl-originated activity (of the total activity) for americium, curium and neptunium. The separation methods developed in this study yielded good chemical recovery for the elements investigated and adequately pure fractions for radiometric activity determination. The extraction chromatographic methods were faster compared to older methods based on ion exchange chromatography. In addition, extraction chromatography is a more environmentally friendly separation method than ion exchange, because less acidic waste solutions are produced during the analytical procedures. (orig.)

Pyrometallurgical partitioning of uranium and transuranic elements from rare earth elements by electrorefining and reductive extraction

International Nuclear Information System (INIS)

Uozumi, Koichi; Kinoshita, Kensuke; Inoue, Tadashi; Storvick, T.S.; Krueger, C.L.; Nabelek, C.R.

2001-01-01

High-level liquid waste generated from PUREX reprocessing contains a small amount of transuranic elements, such as Np, Pu, Am, and Cm, with long-lived radioactivities. A pyrometallurgical partitioning process is being developed to recover transuranic elements from such waste. Small amounts of U contained in the high-level liquid waste are also recovered in the process. A key issue for developing the process is effective separation of U and the transuranic elements from the rare-earth elements, because the two elemental groups are chemically analogous. A series of process tests were carried out in the present study to demonstrate that a combination of electrorefining and reductive extraction is useful for separating U and transuranic elements from the rare-earth elements. The results indicate that 99% of U and each transuranic elements is recovered by the combination process as a product, and that the quantity of rare-earth elements contained in the product is smaller than the transuranic elements by weight. The overall mass balance of U and transuranic elements in the system ranged within the experimental errors assigned to sampling and analysis. (author)

Determination of the oxygen-metal-ratio of uranium-americium mixed oxides

International Nuclear Information System (INIS)

Bartscher, W.

1982-01-01

During the dissolution of uranium-americium mixed oxides in phosphoric acid under nitrogen tetravalent uranium is oxidized by tetravalent americium. The obtained hexavalent uranium is determined by constant potential coulometry. The coulombs measured are equivalent to the oxygen in excess of the minimum composition of UO 2 x AmO 1 . 5 . The total uranium content of the sample is determined in a subsequent coulometric titration. The oxygen-metal ratio of the sample can be calculated for a given uranium-americium ratio. An excess of uranium dioxide is necessary in order to suppress the oxidation of water by tetravalent americium. The standard deviation of the method is 0.0017 O/M units. (orig.) [de

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

Separation by sequential chromatography of americium, plutonium and neptunium elements: application to the study of trans-uranian elements migration in a European lacustrine system

International Nuclear Information System (INIS)

Michel, H.

1999-01-01

The nuclear tests carried out in the atmosphere in the Sixties, the accidents and in particular that to the power station of Chernobyl in 1986, were at the origin of the dispersion of a significant quantity of transuranic elements and fission products. The study of a lake system, such that of the Blelham Tarn in Great Britain, presented in this memory, can bring interesting answers to the problems of management of the environment. The determination of the radionuclides in sediment cores made it possible not only to establish the history of the depositions and consequently the origin of the radionuclides, but also to evaluate the various transfers which took place according to the parameters of the site and the properties of the elements. The studied transuranic elements are plutonium 238, 239-240, americium 241 and neptunium 237. Alpha emitting radionuclides, their determination requires complex radiochemical separations. A method was worked out to successively separate the three radioelements by using a same chromatographic column. Cesium 137 is the studied fission product, its determination is done by direct Gamma spectrometry. Lead 210, natural radionuclide, whose atmospheric flow can be supposed constant. makes it possible to obtain a chronology of the various events. The detailed vertical study of sediment cores showed that the accumulation mode of the studied elements is the same one and that the methods of dating converge. The cesium, more mobile than transuranic elements in the atmosphere, was detected in the 1963 and 1986 fallout whereas an activity out of transuranic elements appears only for the 1963 fallout. The activity of the 1963 cesium fallout is of the same order of magnitude as that of 1986. The calculation of the diffusion coefficients of the elements in the sediments shows an increased migration of cesium compared to transuranic elements. An inventory on the whole of the lake made it possible to note that the atmospheric fallout constitute the

1976 Hanford americium-exposure incident: external decontamination procedures

International Nuclear Information System (INIS)

Jech, J.J.; Berry, J.R.; Breitenstein, B.D.

1982-01-01

An accident resulted in the deposition on an injured workman's skin surfaces, in acid-burned areas and in lacerations, of something in excess of 6 mCi americium-241. The external decontamination procedures used, the change in americium content of the skin during the course of treatment, and some of the unusual problems encountered from the extrusion of foreign material and flaking of skin and scar tissue are described

Pretreatment of americium/curium solutions for vitrification

International Nuclear Information System (INIS)

Rudisill, T.S.

1996-01-01

Vitrification will be used to stabilize an americium/curium (Am/Cm) solution presently stored in F-Canyon for eventual transport to the heavy isotope programs at Oak Ridge National Laboratory. Prior to vitrification, an in-tank oxalate precipitation and a series of oxalic/nitric acid washes will be used to separate these elements and lanthanide fission products from the bulk of the uranium and metal impurities present in the solution. Pretreatment development experiments were performed to understand the behavior of the lanthanides and the metal impurities during the oxalate precipitation and properties of the precipitate slurry. The results of these experiments will be used to refine the target glass composition allowing optimization of the primary processing parameters and design of the solution transfer equipment

Investigation of factors affecting the quality of americium electroplating.

Science.gov (United States)

Trdin, M; Benedik, L; Samardžija, Z; Pihlar, B

2012-09-01

Four different electrolyte solutions were used in the electrodeposition of americium and their influences on the quality of the thin layer of deposited americium isotopes in combination with three different cathode disc materials were investigated. The relations between alpha spectral resolution and disc surface properties were established. Copyright © 2012 Elsevier Ltd. All rights reserved.

Method of isolation of traces of americium by using the +6 oxidation state properties

International Nuclear Information System (INIS)

Kwinta, Jean; Michel, Jean-Jacques

1969-05-01

The authors present a method to separate traces of americium from a solution containing fission products and actinides. This method comprises the following steps: firstly, the oxidation of americium at the +6 state by ammonium persulfate and carrying over of actinides and III and IV lanthanides by lanthanum fluoride; secondly, the reduction by hydrazine of the oxidized americium and carrying over of the reduced americium by lutetium fluoride; and thirdly, the americium-lutetium separation by selective extractions either with di 2 ethyl hexyl phosphoric acid, or by fractionated elution on an anionic resin column by a mixture of nitric acid and methanol [fr

Americium-241 - ED 4308

International Nuclear Information System (INIS)

Ammerich, M.; Frot, P.; Gambini, D.; Gauron, C.; Moureaux, P.; Herbelet, G.; Lahaye, T.; Le Guen, B.; Pihet, P.; Rannou, A.; Vidal, E.

2012-12-01

This sheet presents the characteristics of Americium-241, its origin, and its radio-physical and biological properties. It briefly describes its use in nuclear medicine. It indicates its dosimetric parameters for external exposure, cutaneous contamination, and internal exposure due to acute contamination or to chronic contamination. It indicates and comments the various exposure control techniques: ambient dose rate measurement, surface contamination measurement, atmosphere contamination. It addresses the means of protection: premise design, protection against external exposure and against internal exposure. It describes how areas are delimited and controlled within the premises: regulatory areas, controls to be performed. It addresses the personnel classification, training and medical survey. It addresses the issue of wastes and effluents. It briefly recalls the administrative procedures related to the authorization and declaration of possession and use of sealed and unsealed sources. It indicates regulatory aspects related to the road transport of Americium-241, describes what is to be done in case of incident or accident (for the different types of contamination or exposure)

Plutonium, americium, and uranium in blow-sand mounds of safety-shot sites at the Nevada Test Site and the Tonopah Test Range

International Nuclear Information System (INIS)

Essington, E.H.; Gilbert, R.O.; Wireman, D.L.; Brady, D.N.; Fowler, E.B.

1977-01-01

Blow-sand mounds or miniature sand dunes and mounds created by burrowing activities of animals were investigated by the Nevada Applied Ecology Group (NAEG) to determine the influence of mounds on plutonium, americium, and uranium distributions and inventories in areas of the Nevada Test Site and Tonopah Test Range. Those radioactive elements were added to the environment as a result of safety experiments of nuclear devices. Two studies were conducted. The first was to estimate the vertical distribution of americium in the blow-sand mounds and in the desert pavement surrounding the mounds. The second was to estimate the amount or concentration of the radioactive materials accumulated in the mound relative to the desert pavement. Five mound types were identified in which plutonium, americium, and uranium concentrations were measured: grass, shrub, complex, animal, and diffuse. The mount top (that portion above the surrounding land surface datum), the mound bottom (that portion below the mound to a depth of 5 cm below the surrounding land surface datum), and soil from the immediate area surrounding the mound were compared separately to determine if the radioactive elements had concentrated in the mounds. Results of the studies indicate that the mounds exhibit higher concentrations of plutonium, americium, and uranium than the immediate surrounding soil. The type of mound does not appear to have influenced the amount of the radioactive material found in the mound except for the animal mounds where the burrowing activities appear to have obliterated distribution patterns

Research program on development of advanced treatment technology for americium-containing aqueous waste in NUCEF

Energy Technology Data Exchange (ETDEWEB)

Mineo, Hideaki; Matsumura, Tatsuro; Tsubata, Yasuhiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1996-10-01

A research program was prepared on the development of an advanced treatment process for the americium-containing concentrated aqueous waste in NUCEF, than allows americium recovery for the reuse and the reduction of TRU waste generation. A preliminary analysis was conducted on the separation requirements based on the components estimated for the waste. An R and D strategy was proposed from the view to reduce TRU waste generated in the processing that the highest priority is given on the control of TRU leakage such as americium into the effluent stream after americium recovery and the minimization of salt used in the separation over the decontamination of impurities from americium. The extraction chromatographic method was selected as a candidate technology for americium separation under the principle to use reagents that are functional in acidic conditions such as bidentate extractants of DHEDECMP, CMPO or diamides, considering the larger flexibilities in process modification and possible multi-component separation with compact equipment and the past achievements on the recovery of kg quantities of americium. Major R and D items extracted are screening and evaluation of extractants for americium and plutonium, optimization of separation conditions, selection of denitration method, equipment developments and development of solidification methods of discarded americium after reuse and of various kinds of separation residues. In order to cope these items, four steps of R and D program were proposed, i.e., fundamental experiment in beaker-scale on screening and evaluation of extractants, flowsheet study in bench-scale using simulated and small amount of americium aqueous waste solution to evaluate candidate process, americium recovery test in iron-shielded cell to be installed in NUCEF. It is objected to make recovery of 100g orders of americium used for research on fundamental TRU fuel properties. (J.P.N.)

Rare earth element lithogeochemistry of granitoid mineral deposits

Energy Technology Data Exchange (ETDEWEB)

Taylor, R.P.; Fryer, B.J. (Memorial Univ. of Newfoundland, St. John' s (Canada). Dept. of Earth Sciences)

1983-12-01

As a monitor of the processes involved in the formation of granitoid mineral deposits the coherent group behaviour of the rare earth elements (REE) actively reflects changing fluid characteristics. For example, in the porphyry environment, magmatic-hydrothermal fluids produce potassic alteration with strong enrichment in the light rare earth elements, reflecting their high pH, low fluid/rock ratios, and the dominant role of Cl/sup -/ complexing in metal (i.e. Cu, Au) transport. With increasing fluid/rock ratios and decreasing pH accompanying the progressive involvement of meteoric fluids (and the production of propylitic, argillic, and phyllic alteration) anionic species such as F/sup -/ and CO/sub 3//sup 2 -/ become important in metal (e.g. Mo, W) transport through complexing, and their activity in the hydrothermal fluids is illustrated by mobilization of the heavy rare earth elements. The relative involvement of Cl/sup -/ versus F/sup -/ versus CO/sub 3//sup 2 -/ in metal transport in other granite-related systems can also be monitored through REE behaviour. Hence granitoid tin-tungsten mineralization and associated greisenization typically exhibit heavy rare earth enrichment and evidence the importance of F/sup -/ and CO/sub 3//sup 2 -/ in metal transport. Similarly, heavy rare earth element enrichment in hydrothermal uranium deposits can be related to the transport of uranium as carbonate complexes. REE are widely accepted as powerful tools in the study of rock petrogenesis, but their use has been neglected in the investigation of mineral deposits. The recognition of the systematic variation of REE distributions in granitoid mineral deposits suggests that the application of REE geochemistry, particularly when integrated with fluid inclusion and isotope studies, can provide l) an effective method for identifying the physiochemical controls of metal transport and 2) a useful criterion of elucidating metal distribution.

Rare earth element lithogeochemistry of granitoid mineral deposits

International Nuclear Information System (INIS)

Taylor, R.P.; Fryer, B.J.

1983-01-01

As a monitor of the processes involved in the formation of granitoid mineral deposits the coherent group behaviour of the rare earth elements (REE) actively reflects changing fluid characteristics. For example, in the porphyry environment, magmatic-hydrothermal fluids produce potassic alteration with strong enrichment in the light rare earth elements, reflecting their high pH, low fluid/rock ratios, and the dominant role of Cl - complexing in metal (i.e. Cu, Au) transport. With increasing fluid/rock ratios and decreasing pH accompanying the progressive involvement of meteoric fluids (and the production of propylitic, argillic, and phyllic alteration) anionic species such as F - and CO 3 2- become important in metal (e.g. Mo, W) transport through complexing, and their activity in the hydrothermal fluids is illustrated by mobilization of the heavy rare earth elements. The relative involvement of Cl - versus F - versus CO 3 2- in metal transport in other granite-related systems can also be monitored through REE behaviour. Hence granitoid tin-tungsten mineralization and associated greisenization typically exhibit heavy rare earth enrichment and evidence the importance of F - and CO 3 2- in metal transport. Similarly, heavy rare earth element enrichment in hydrothermal uranium deposits can be related to the transport of uranium as carbonate complexes. REE are widely accepted as powerful tools in the study of rock petrogenesis, but their use has been neglected in the investigation of mineral deposits. The recognition of the systematic variation of REE distributions in granitoid mineral deposits suggests that the application of REE geochemistry, particularly when integrated with fluid inclusion and isotope studies, can provide l) an effective method for identifying the physiochemical controls of metal transport and 2) a useful criterion of elucidating metal distribution

Earth, Air, Fire and Water in Our Elements

Science.gov (United States)

Lievesley, Tara

2007-01-01

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

Peculiarities of rare-earth-element distribution in environmental objects

International Nuclear Information System (INIS)

Gorbunov, A.V.; Onischenko, T.L.; Gundorina, S.F.; Frontasyeva, M.V.

1993-01-01

The effect of the production of phosphorus fertilizers on the pollution of the environment by rare-earth elements is reviewed. The main sources of rare-earth element pollution in the environment are described. The levels of REEs in components of the environment - atmosphere, snow, different types of soil, native and agricultural types of vegetation - that provide evidence for their participation in the biological cycle of plants are considered. The high values of the correlation coefficients lead one to think that the REE distribution in vegetation occurs under specific laws true for this family of elements. (author) 9 refs.; 6 figs.; 5 tabs

Rare earth element recycling from waste nickel-metal hydride batteries

International Nuclear Information System (INIS)

Yang, Xiuli; Zhang, Junwei; Fang, Xihui

2014-01-01

Highlights: • Leaching kinetics of REEs has rarely been reported. • A new method, including hydrochloric acid leaching and oxalic acid precipitation, was proposed. • REEs recovery rate of 95.16% and pure rare earth oxides of 99% were obtained. • Leaching process was controlled by chemical reaction. • The kinetic equation was determined. - Abstract: With an increase in number of waste nickel-metal hydride batteries, and because of the importance of rare earth elements, the recycling of rare earth elements is becoming increasingly important. In this paper, we investigate the effects of temperature, hydrochloric acid concentration, and leaching time to optimize leaching conditions and determine leach kinetics. The results indicate that an increase in temperature, hydrochloric acid concentration, and leaching time enhance the leaching rate of rare earth elements. A maximum rare earth elements recovery of 95.16% was achieved at optimal leaching conditions of 70 °C, solid/liquid ratio of 1:10, 20% hydrochloric acid concentration, −74 μm particle size, and 100 min leaching time. The experimental data were best fitted by a chemical reaction-controlled model. The activation energy was 43.98 kJ/mol and the reaction order for hydrochloric acid concentration was 0.64. The kinetic equation for the leaching process was found to be: 1−(1−x) 1/3 =A/ρr 0 [HCl] 0.64 exp((−439,800)/(8.314T) )t. After leaching and filtration, by adding saturated oxalic solution to the filtrate, rare earth element oxalates were obtained. After removing impurities by adding ammonia, filtering, washing with dilute hydrochloric acid, and calcining at 810 °C, a final product of 99% pure rare earth oxides was obtained

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.)

Rapid separation of individual rare-earth elements from fission products

International Nuclear Information System (INIS)

Baker, J.D.; Gehrke, R.J.; Greenwood, R.C.; Meikrantz, D.H.

1980-01-01

A microprocessor-controlled radiochemical separation system has been developed to rapidly separate rare-earth elements from gross fission products. The system is composed of two high performance liquid chromatography columns coupled in series by a stream-splitting injection valve. The first column separates the rare-earth group by extraction chromatography using dihexyldiethylcarbamylmethylenephosphonate (DHDECMP) adsorbed on Vydac C 8 resin. The second column isolates the individual rare-earth elements by cation exchange using Aminex A-9 resin with α-hydroxyisobutyric acid (α-HIBA) as the eluent. With this system, fission-product rare-earth isotopes with half-lives as short as three minutes have been studied

Behaviour of Rare Earth Elements during the Earth's core formation

Science.gov (United States)

Faure, Pierre; Bouhifd, Mohamed Ali; Boyet, Maud; Hammouda, Tahar; Manthilake, Geeth

2017-04-01

Rare Earth Elements (REE) are classified in the refractory group, which means that they have a high temperature condensation and their volatility-controlled fractionation is limited to high-temperature processes. Anomalies have been measured for Eu, Yb and Sm, which are the REE with the lowest condensation temperatures in CAIs and chondrules (e.g. [1]). REE are particularly abundant in the sulfides of enstatite chondrites, 100 to 1000 times the CI value [e.g. 2,3], proving that these elements are not strictly lithophile under extremely reducing conditions. However by investigating experimentally the impact of Earth's core formation on the behavior of Sm and Nd, we have shown the absence of fractionation between Sm and Nd during the segregation of the metallic phase [4]. Recently, Wohlers and Wood [5] proposed that Nd and Sm could be fractionated in presence of a S-rich alloy phase. However, their results were obtained at pressure and temperature conditions below the plausible conditions of the Earth's core formation. Clearly, large pressure range needs to be covered before well-constrained model can be expected. Furthermore, our preliminary metal-silicate partitioning results show that Ce and Eu have higher metal/silicate partition coefficients than their neighboring elements, and that the presence of sulphur enhances the relative difference between partition coefficients. In this presentation, we will present and discuss new metal-silicate partition coefficients of all REE at a deep magma ocean at pressures ranging from those of the uppermost upper mantle ( 5 GPa) to a maximum pressure expected in the range of 20 GPa, temperatures ranging from 2500 to about 3000 K, and oxygen fugacities within IW-1 to IW-5 (1 to 5 orders of magnitude lower than the iron-wüstite buffer). We will discuss the effect of S, as well as the effect of H2O on the behaviour of REE during the Earth's core formation: recent models suggest that contrary to currently accepted beliefs, the

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

Determination of americium and curium using ion-exchange in the nitric-acid-methanol medium for environmental analysis

International Nuclear Information System (INIS)

Holm, E.; Fukai, R.

1976-01-01

While transplutonic elements are only slightly sorbed to anion exchangers from hydrochloric or nitric acid media, the presence of alcohol enhances the anionic exchange of these elements, especially in nitric and sulfuric solutions. In the present work a method has been developed for determining americium and curium in environmental samples, on the basis of the difference between the sorption characteristics to anion exchangers in the acid-methanol system of these transplutonic elements and those of plutonium, polonium and thorium. The method also permits us to perform sequential determination of plutonium, when necessary

Analytical separation of americium and curium, using high performance liquid chromatography

International Nuclear Information System (INIS)

Billon, A.

1978-01-01

Americium and curium are separated on a column of cation exchange resin (Aminex) using hydroxyisobutyric acid (α HIBA) as eluent, at a temperature of 80 0 C. Americium and curium were detected in line using their α emission: the separation was performed in a shielded glove box whose setting-up is given. Finally, the time necessary for a separation is comprised between 30 min and 1 hr. The purity of separated fractions was assayed by mass-spectrometry. An application in the determination of isotopic composition of americium and curium in fuels is described

Uncovering the end uses of the rare earth elements

Energy Technology Data Exchange (ETDEWEB)

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

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. - Highlights: • We have derived the first quantitative end use information of the rare earths (REE). • The results are for individual REE from 1995 to 2007. • The end uses of REE in China, Japan, and the US changed dramatically in quantities and structure. • This information can provide solid foundation for decision and strategy making.

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

Recovery and purification of rare earth elements and thorium

International Nuclear Information System (INIS)

Sungur, A.; Saygi, Z.; Yildiz, H.

1985-01-01

Rare earth elements and thorium found in the low-grade Eskisehir-Beylikahir ore have been recovered by HCl leaching, Lanthanides and thorium were separated and purified from the leach solutions through the precipitation sequence as double sulphate, hydroxide and oxalate. The Ln 2 O 3 and Th(OH) 4 products, finally obtained contained 36% Ce and 65% Th. The analysis of rare earth elements, thorium and other present ingredients were carried out by instrumental neutron activation analysis, atomic absorption spectroscopy, vis-spectroscopy and gravimetry. (author)

Low-level determination of transuranic elements in marine environment samples

International Nuclear Information System (INIS)

Ballestra, S.; Holm, E.; Fukai, R.

1978-01-01

The procedures developed and currently employed in the Monaco Laboratory for determining transuranic elements in seawater, marine sediments and organisms are described and discussed. While the standard anion-exchange procedure from the hydrochloric acid medium is used for the separation of plutonium isotopes from americium, purification of americium and curium is achieved by an ion-exchange sorption from the methanol-nitric acid medium, followed by an elution with the methanol-hydrochloric acid mixture. Satisfactory clean-up of plutonium as well as americium and curium can be achieved by applying the described procedures. (author)

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

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

Relationship between accumulation of rare earth element in tumor and ionic radius

Energy Technology Data Exchange (ETDEWEB)

Kataoka, N [Kanazawa Univ. (Japan). School of Medicine

1975-02-01

The accumulation of rare earth elements in the different organs of Ehrlich's tumor-bearing mice at 48 hours after intraperitoneal administration was measured by a Ge(Li) semiconductor detector. Accumulation of all the rare earth elements was the highest in the pancreas. Accumulation of /sup 152/Eu in the different organs of Ehrlich's tumor-bearing mice was very high. The accumulation of rare earth elements in Ehrlich's tumor was lower than the accumulation of /sup 67/Ga and /sup 46/Sc. The tumor-organ concentration ratio of rare earth elements was remarkably lower than the accumulation of /sup 67/Ga and /sup 46/Sc. However, the accumulation of /sup 152/Eu in Ehrlich's tumor was somewhat higher than that of /sup 67/Ga. The relationship between the accumulation and the carrier content was examined. The lower the carrier content was, the higher was the accumulation in different organs. However, the carrier effect of rare earth on the uptake in different organs elements was slight. The author postulated that the elements in which the ionic radius is similar to that of Mg(0.62 A) or Ca(0.99 A) are abundant in the tumor cell membrane, and they might pass through the tumor cell membrane much more easily than would the other elements. However, the result was negative.

Preparation of americium source for smoke detector

International Nuclear Information System (INIS)

Ramaswami, A.; Singh, R.J.; Manohar, S.B.

1994-01-01

This report describes the method developed for the preparation of 241 Am source for smoke detector. Americium was electrodeposited from iso-propyl alcohol medium on silver backing. Thin layer of gold (few hundred micro gram thick) was plated on the americium source to make it safe for handling. The thickness of plated gold was such that the alpha radiations from the 241 Am source could escape out of the gold layer and cause ionisation in the surrounding air. The performance of the prepared sources were checked in a smoke detector and was found to be satisfactory and comparable to the imported sources. (author). 1 refs., 2 figs., 1 tab

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.

Aqueous Chloride Operations Overview: Plutonium and Americium Purification/Recovery

Energy Technology Data Exchange (ETDEWEB)

Gardner, Kyle Shelton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kimball, David Bryan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Skidmore, Bradley Evan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-09-28

These are a set of slides intended for an information session as part of recruiting activities at Brigham Young University. It gives an overview of aqueous chloride operations, specifically on plutonium and americium purification/recovery. This presentation details the steps taken perform these processes, from plutonium size reduction, dissolution, solvent extraction, oxalate precipitation, to calcination. For americium recovery, it details the CLEAR (chloride extraction and actinide recovery) Line, oxalate precipitation and calcination.

Separation of Americium from plutonium, Annex 3; Prilog 3: Odvajanje amercijuma od plutonijuma

Energy Technology Data Exchange (ETDEWEB)

Cvjeticanin, D; Milic, N; Janicijevic, P; Ratkovic, S [Institute of Nuclear Sciences Boris Kidric, Laboratorija za visoku aktivnost, Vinca, Beograd (Serbia and Montenegro)

1963-12-15

Since there was the possibility of working with plutonium milligram quantities, it was possible to study plutonium with contents of americium, which was expected in the about two years old plutonium solutions. Method for separation of the micro quantities of americium and plutonium was needed as well as a multichannel alpha-pulse analyzer. Method for separation of americium from plutonium by thenol trifluoro-acetone (TTA) and anion exchange was adopted.

Extraction of americium from acid aqueous solutions by diethyl-2-hexyl-pyro-phosphoric acid

International Nuclear Information System (INIS)

Guillaume, Bernard

1971-02-01

After having outlined the interesting properties of americium and the difficulties of its recovery, the author reports the study of the mechanism of extraction of americium from acid aqueous solutions by using the diethyl-2hexyl-pyro-phosphoric acid. Several aspects are thus discussed: influence of concentration of H 2 DEHPP, influence of the acidity of the aqueous phase, saturation of extracting agent, influence of the diluting agent, complexing of americium, influence of other cations. In a second part, the author reports the application to the recovery of americium from effluents, and discusses the obtained results

Environmental impact of a teratogenic actinide: a case study of americium-241

Energy Technology Data Exchange (ETDEWEB)

Wang, J.; Yang, J.Y.

1985-10-16

Americium-241 is widely used as a radiation source, but it also has some potential risk if taken into the body. Although the radiotoxicity of americium-241 is small compared to other transuranic actinides, its effects on the reproductive system and on development of the placenta are more damaging than the effects of plutonium-239. A previous report based on a worst-case scenario involving a hypothetical fire accident in a contaminated facility indicated that there could have been a significant impact on nearby residents from a unit release of americium-241 via atmospheric dispersion. However, because the facility is located in a rural region where most drinking water supplies are drawn from private wells, it is believed that deposition of americium-241 from the atmosphere might also have impacts via the groundwater pathway by infiltration of rainwater. In this analysis, a three-dimensional analytical mathematical model is used to assess several aspects of americium-241 contamination of groundwater, including radioactive transformation, advection, dispersion, and soil sorption. Simulation results indicate that no significant radiological impacts would occur to the nearby residents via the groundwater pathway. 15 refs., 2 figs., 2 tabs.

Environmental impact of a teratogenic actinide: a case study of americium-241

International Nuclear Information System (INIS)

Wang, J.; Yang, J.Y.

1985-01-01

Americium-241 is widely used as a radiation source, but it also has some potential risk if taken into the body. Although the radiotoxicity of americium-241 is small compared to other transuranic actinides, its effects on the reproductive system and on development of the placenta are more damaging than the effects of plutonium-239. A previous report based on a worst-case scenario involving a hypothetical fire accident in a contaminated facility indicated that there could have been a significant impact on nearby residents from a unit release of americium-241 via atmospheric dispersion. However, because the facility is located in a rural region where most drinking water supplies are drawn from private wells, it is believed that deposition of americium-241 from the atmosphere might also have impacts via the groundwater pathway by infiltration of rainwater. In this analysis, a three-dimensional analytical mathematical model is used to assess several aspects of americium-241 contamination of groundwater, including radioactive transformation, advection, dispersion, and soil sorption. Simulation results indicate that no significant radiological impacts would occur to the nearby residents via the groundwater pathway. 15 refs., 2 figs., 2 tabs

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

Microstructure and elemental distribution of americium containing MOX fuel under the short term irradiation tests

International Nuclear Information System (INIS)

Tanaka, Kosuke; Hirosawa, Takashi; Obayashi, Hiroshi; Koyama, Shin Ichi; Yoshimochi, Hiroshi; Tanaka, Kenya

2008-01-01

In order to investigate the effect of americium addition to MOX fuels on the irradiation behavior, the 'Am-1' program is being conducted in JAEA. The Am-1 program consists of two short term irradiation tests of 10-minute and 24 hour irradiations and a steady-state irradiation test. The short-term irradiation tests were successfully completed and the post irradiation examinations (PIEs) are in progress. The PIEs for Am-containing MOX fuels focused on the microstructural evolution and redistribution behavior of Am at the initial stage of irradiation and the results to date are reported

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

Science.gov (United States)

Showstack, Randy

2012-03-01

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

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.

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.

Determination of rare earth elements by liquid chromatography/inductively coupled plasma atomic emission spectrometry

International Nuclear Information System (INIS)

Yoshida, K.; Haraguchi, H.

1984-01-01

Inductively coupled plasma atomic emission spectrometry (ICP-AES) interfaced with high-performance liquid chromatography (HPLC) has been applied to the determination of rare earth elements. ICP-AES was used as an element-selective detector for HPLC. The separation of rare earth elements with HPLC helped to avoid erroneous analytical results due to spectral interferences. Fifteen rare earth elements (Y and 14 lanthanides) were determined selectively with the HPLC/ICP-AES system using a concentration gradient method. The detection limits with the present HPLC/ICP-AES system were about 0.001-0.3 μg/mL with a 100-μL sample injection. The calibration curves obtained by the peak height measurements showed linear relationships in the concentration range below 500 μg/mL for all rare earth elements. A USGS rock standard sample, rare earth ores, and high-purity lanthanide reagents (>99.9%) were successfully analyzed without spectral interferences

Biochemical fractionation and cellular distribution of americium and plutonium in the biomass of freshwater macrophytes

International Nuclear Information System (INIS)

Zotina, T.A.; Kalacheva, G.S.; Bolsunovsky, A.Ya.

2011-01-01

Accumulation of americium ( 241 Am) and plutonium ( 238,242 Pu) and their distribution in cell compartments and biochemical components of the biomass of freshwater aquatic plants Elodea canadensis, Ceratophyllum demersum and Myrioplyllum spicatum and aquatic moss Fontinalis antipyretica have been investigated in laboratory experiments. Americium and plutonium taken up from water by Elodea canadensis apical shoots were mainly absorbed by structural components of plant cells (90% for 241 Am; 89% for 238 Pu and 82-87% for 242 Pu). About 10-18% of isotope activity was recorded in the cytosol fraction. The major concentration (76-92%) of americium was bound to cell wall cellulose-like polysaccharides of Elodea canadensis, Myriophyllum spicatum, Ceratophyllum demersum and Fontinalis antipyretica, 8-24% of americium activity was registered in the fraction of proteins and carbohydrates, and just a minor concentration (<1%) in the lipid fraction. The distribution of plutonium in the biomass fractions of Elodea was similar to that of americium. Hence, americium and plutonium had the highest affinity to cellulose-like polysaccharides of cell walls of freshwater submerged macrophytes. (author)

Extraction of transplutonium elements from carbonate solutions by alkylpyrocatechol

International Nuclear Information System (INIS)

Karalova, Z.K.; Myasoedov, B.F.; Rodionova, L.M.; Kuznetsova, V.S.

1983-01-01

Extraction of americium, berkelium as well as Ce, Eu, Th, U, Zr, Cs, Fe with solution of 4(α, α-dioctylethyl)pyrocatechol (DOP) in toluene from carbonate solutions to determine conditions of their separation has been studied. It is established that americium extraction is quite sensitive to the changes of potassium carbonate concentration. The maximum extraction of americium (R >90%) is observed in the case of 0.1-0.5 mol/l of K 2 CO 3 solutions and the minimum one (R=2.5%) - in the case of 8 mol/l K 2 CO 3 . Americium extraction increases sharply when sodium hydroxide is introduced in carbonate solutions. It is shown that varying sodium hydroxide concentration it is possible to achieve qualitative extraction of americium even from saturated solution of potassium carbonate. Reextraction of TPE is easily realized with 3 mol/l HCl solution. The system K 2 CO 3 (KOH)-DOP proved to be perspective for Am separation from Bk, Ce, Cs, actinoid elements as well as from Fe

Pyrochemical investigations into recovering plutonium from americium extraction salt residues

International Nuclear Information System (INIS)

Fife, K.W.; West, M.H.

1987-05-01

Progress into developing a pyrochemical technique for separating and recovering plutonium from spent americium extraction waste salts has concentrated on selective chemical reduction with lanthanum metal and calcium metal and on the solvent extraction of americium with calcium metal. Both techniques are effective for recovering plutonium from the waste salt, although neither appears suitable as a separation technique for recycling a plutonium stream back to mainline purification processes. 17 refs., 13 figs., 2 tabs

Supercritical Fluid Extraction of Plutonium and Americium from Soil

International Nuclear Information System (INIS)

Fox, R.V.; Mincher, B.J.

2002-01-01

Supercritical fluid extraction (SFE) of plutonium and americium from soil was successfully demonstrated using supercritical fluid carbon dioxide solvent augmented with organophosphorus and beta-diketone complexants. Spiked Idaho soils were chemically and radiologically characterized, then extracted with supercritical fluid carbon dioxide at 2,900 psi and 65 C containing varying concentrations of tributyl phosphate (TBP) and thenoyltrifluoroacetone (TTA). A single 45 minute SFE with 2.7 mol% TBP and 3.2 mol% TTA provided as much as 88% ± 6.0 extraction of americium and 69% ± 5.0 extraction of plutonium. Use of 5.3 mol% TBP with 6.8 mol% of the more acidic beta-diketone hexafluoroacetylacetone (HFA) provided 95% ± 3.0 extraction of americium and 83% ± 5.0 extraction of plutonium in a single 45 minute SFE at 3,750 psi and 95 C. Sequential chemical extraction techniques were used to chemically characterize soil partitioning of plutonium and americium in pre-SFE soil samples. Sequential chemical extraction techniques demonstrated that spiked plutonium resides primarily (76.6%) in the sesquioxide fraction with minor amounts being absorbed by the oxidizable fraction (10.6%) and residual fractions (12.8%). Post-SFE soils subjected to sequential chemical extraction characterization demonstrated that 97% of the oxidizable, 78% of the sesquioxide and 80% of the residual plutonium could be removed using SFE. These preliminary results show that SFE may be an effective solvent extraction technique for removal of actinide contaminants from soil

Gut uptake factors for plutonium, americium and curium

International Nuclear Information System (INIS)

Harrison, J.D.

1982-01-01

Data on estimates of the absorption of plutonium, americium and curium from the human gut based on measurements of uptake in other mammalian species are reviewed. It is proposed that for all adult members of the public ingesting low concentrations of plutonium in food and water, 0.05% would be an appropriate value of absorption except when the conditions of exposure are known and a lower value can be justified. For dietary intakes of americium and curium, the available data do not warrant a change from the ICRP value of 0.05%. For newborn children ingesting americium, curium and soluble forms of plutonium, a value of 1% absorption is proposed for the first 3 months of life during which the infant is maintained on a milk diet. It is proposed that a value of 0.5% should be used for the first year of life to take account of the gradual maturation of the gut. In considering the ingestion of insoluble oxides of plutonium by infants, it is proposed that absorption is taken as 0.1% for the first 3 months and 0.05% for the first year. (author)

Uptake of americium-241 by algae and bacteria

Energy Technology Data Exchange (ETDEWEB)

Giesy, Jr, J P; Paine, D [Savannah River Ecology Lab., Aiken, S.C. (USA)

1978-01-01

The uptake of americium by three algae, Scenedesmus obliguus, Selenastrum capricomutum and Chlorella pyrenosdosa and a bacterium Aeromonas hydrophila was studied. Live and fixed cells of each algal species and live bacterial cells were used. It is shown that algae and bacteria concentrate americium 241 to a high degree which makes them important links in the biomagnification phenomenon which may ultimately lead to a human hazard and be potentially important in recycling Am /sup 241/ in the water column and mobilization from sediments. Chemical fixation of algal cells caused increased uptake which indicated that uptake is by passive diffusion and probably due to chemical alteration of surface binding sites.

[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.

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

Distribution coefficients for plutonium and americium on particulates in aquatic environments

International Nuclear Information System (INIS)

Sanchez, A.L.; Schell, W.R.; Sibley, T.H.

1982-01-01

The distribution coefficients of two transuranic elements, plutonium and americium, were measured experimentally in laboratory systems of selected freshwater, estuarine, and marine environments. Gamma-ray emitting isotopes of these radionuclides, 237 Pu and 241 Am, were significantly greater than the sorption Ksub(d) values, suggesting some irreversibility in the sorption of these radionuclides onto sediments. The effects of pH and of sediment concentration on the distribution coefficients were also investigated. There were significant changes in the Ksub(d) values as these parameters were varied. Experiments using sterilized and nonsterilized samples for some of the sediment/water systems indicate possible bacterial effects on Ksub(d) values. (author)

Extraction of rare earth elements from low-grade Bauxite via precipitation reaction

Science.gov (United States)

Kusrini, E.; Nurani, Y.; Bahari, ZJ

2018-03-01

The aim of this research was to determine the optimum hydrometallurgical parameters to extract the rare earth elements (REE) from low-grade bauxite through acid leaching and precipitation reaction. REE or lanthanide recovery by a precipitation method with sodium sulphate and sodium phosphate as precipitation agents is reported where the effect of pH and recovery of REE are described. The metal composition of REE in low-grade bauxite after treatment were analyzed by ICP-OES. The total recovery values of REE elements at the first precipitation reaction using sodium sulphate as the precipitation agent at pH 3.5 showed ~68.2% of lanthanum, ~18.9% cerium, and ~7.8% yttrium. Lanthanum was the rare-earth element present at the highest concentration in the low-grade bauxite after the series treatments. An optimum pH of 3.5 for precipitation of rare-earth elements using sodium sulphate was demonstrated where this method is recommended for the extraction of REE elements from low-grade bauxite.

Origin of the earth's moon: constraints from alkali volatile trace elements

International Nuclear Information System (INIS)

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

1986-01-01

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

Synergistic extraction behaviour of americium from simulated acidic waste solutions

International Nuclear Information System (INIS)

Pathak, P.N.; Veeraraghavan, R.; Mohapatra, P.K.; Manchanda, V.K.

1998-01-01

The extraction behaviour of americium has been investigated with mixtures of 3-phenyl-4-benzoyl-5-isoxazolone (PBI) and oxodonors viz. tri-n-butyl phosphate (TBP), tri-n-octyl phosphine oxide (TOPO) and di-n-butyl octanamide (DBOA) using dodecane as the diluent from 1-6 M HNO 3 media. It is observed that D Am remains unaltered with PBI concentration (in the range 0.06-0.1 M) at 1.47 M TBP in the entire range of HNO 3 concentration. PBI and TBP in combination appears more promising compared to other synergistic systems. The possibility of using this mixture for americium removal from high level liquid waste solution has been explored. Extraction studies indicated that prior removal of uranium by 20% TBP in dodecane is helpful in the quantitative recovery of americium in three contacts. Effect of lanthanides on D Am is found to be marginal. (orig.)

Reduction Rates for Higher Americium Oxidation States in Nitric Acid

Energy Technology Data Exchange (ETDEWEB)

Grimes, Travis Shane [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mincher, Bruce Jay [Idaho National Lab. (INL), Idaho Falls, ID (United States); Schmitt, Nicholas C [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-09-30

The stability of hexavalent americium was measured using multiple americium concentrations and nitric acid concentrations after contact with the strong oxidant sodium bismuthate. Contrary to our hypotheses Am(VI) was not reduced faster at higher americium concentrations, and the reduction was only zero-order at short time scales. Attempts to model the reduction kinetics using zero order kinetic models showed Am(VI) reduction in nitric acid is more complex than the autoreduction processes reported by others in perchloric acid. The classical zero-order reduction of Am(VI) was found here only for short times on the order of a few hours. We did show that the rate of Am(V) production was less than the rate of Am(VI) reduction, indicating that some Am(VI) undergoes two electron-reduction to Am(IV). We also monitored the Am(VI) reduction in contact with the organic diluent dodecane. A direct comparison of these results with those in the absence of the organic diluent showed the reduction rates for Am(VI) were not statistically different for both systems. Additional americium oxidations conducted in the presence of Ce(IV)/Ce(III) ions showed that Am(VI) is reduced without the typical growth of Am(V) observed in the systems sans Ce ion. This was an interesting result which suggests a potential new reduction/oxidation pathway for Am in the presence of Ce; however, these results were very preliminary, and will require additional experiments to understand the mechanism by which this occurs. Overall, these studies have shown that hexavalent americium is fundamentally stable enough in nitric acid to run a separations process. However, the complicated nature of the reduction pathways based on the system components is far from being rigorously understood.

Ecological effect of rare earth elements

International Nuclear Information System (INIS)

Hu Aitang; Zhou Quansuo; Zheng Shaojian; Zhai Hai; Zhao Xiulan; Pang Yonglin; Wang Yuqi; Sun Jingxin; Zhang Shen; Wang Lijun

1997-01-01

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

Mechanochemical decomposition of monazite to assist the extraction of rare earth elements

Energy Technology Data Exchange (ETDEWEB)

Kim, Wantae; Bae, Inkook; Chae, Soochun [Korea Institute of Geoscience and Mineral Resources, 92 Gwahang-no, Yuseong-gu, Daejeon 305-350 (Korea, Republic of); Shin, Heeyoung, E-mail: hyshin@kigam.re.k [Korea Institute of Geoscience and Mineral Resources, 92 Gwahang-no, Yuseong-gu, Daejeon 305-350 (Korea, Republic of)

2009-11-03

Mechanochemical decomposition by milling a mixture of monazite and sodium hydroxide powder and subsequent leaching by sulfuric acid for the extraction of rare earth elements at room temperature has been investigated. The milling of the mixture allows the mechanochemical formation of rare earth hydroxides and sodium phosphate as milling progresses. Nearly all the monazite is decomposed within 120 min under the present milling conditions. A 0.05N sulfuric acid solution enables us to improve the yield of each of La, Nd and Sm to around 85% or more in the powder milled for 120 min. Also, respective Ce and Pr yields of about 20% and 70% remain un-dissolved since they are changed into oxide forms during and after the milling operation. These rare earth oxides are mostly dissolved as the acid concentration increases to 5N. The yield of rare earth elements increases with increasing milling time. Thus mechanochemical milling plays a significant role in achieving high yield of rare earth elements from the leaching of the milled powder.

Mechanochemical decomposition of monazite to assist the extraction of rare earth elements

International Nuclear Information System (INIS)

Kim, Wantae; Bae, Inkook; Chae, Soochun; Shin, Heeyoung

2009-01-01

Mechanochemical decomposition by milling a mixture of monazite and sodium hydroxide powder and subsequent leaching by sulfuric acid for the extraction of rare earth elements at room temperature has been investigated. The milling of the mixture allows the mechanochemical formation of rare earth hydroxides and sodium phosphate as milling progresses. Nearly all the monazite is decomposed within 120 min under the present milling conditions. A 0.05N sulfuric acid solution enables us to improve the yield of each of La, Nd and Sm to around 85% or more in the powder milled for 120 min. Also, respective Ce and Pr yields of about 20% and 70% remain un-dissolved since they are changed into oxide forms during and after the milling operation. These rare earth oxides are mostly dissolved as the acid concentration increases to 5N. The yield of rare earth elements increases with increasing milling time. Thus mechanochemical milling plays a significant role in achieving high yield of rare earth elements from the leaching of the milled powder.

Americium Separations from High-Salt Solutions Using Anion Exchange

International Nuclear Information System (INIS)

Barr, Mary E.; Jarvinen, Gordon D.; Stark, Peter C.; Chamberlin, Rebecca M.; Bartsch, Richard A.; Zhang, Z.Y.; Zhao, W.

2001-01-01

The aging of the US nuclear stockpile presents a number of challenges, including the increasing radioactivity of plutonium residues due to the ingrowth of 241 Am from the β-decay of 241 Pu. We investigated parameters that affect the sorption of Am onto anion-exchange resins from concentrated effluents derived from nitric acid processing of plutonium residues. These postevaporator wastes are nearly saturated solutions of acidic nitrate salts, and americium removal is complicated by physical factors, such as solution viscosity and particulates, as well as by the presence of large quantities of competing metals and acid. Single- and double-contact batch distribution coefficients for americium and neodymium from simple and complex surrogate solutions are presented. Varied parameters include the nitrate salt concentration and composition and the nitric acid concentration. We find that under these extremely concentrated conditions, Am(III) removal efficiencies can surpass 50% per contact. Distribution coefficients for both neodymium and americium are insensitive to solution acidity and appear to be driven primarily by low water activities of the solutions

Organic components and plutonium and americium state in soils and soil solutions

International Nuclear Information System (INIS)

Sokolik, G.A.; Ovsyannikova, S.V.; Kimlenko, I.M.

2002-01-01

The fraction composition of humus substances of different type soils and soil solutions have been studied. A distribution of Pu 239, 240 and Am 241 between humus substances fractions of different dispersity and mobility in soil-vegetation cover has been established. It was shown that humus of organic soils fixes plutonium and americium in soil medium in greater extent than humus of mineral soils. That leads to lower migration ability of radionuclides in organic soils. The lower ability of americium to form difficultly soluble organic and organic-mineral complexes and predomination of its anion complexes in soil solutions may be a reason of higher mobility and biological availability of americium in comparison to plutonium during soil-plant transfer (authors)

In-line measurement of plutonium and americium in mixed solutions

International Nuclear Information System (INIS)

Li, T.K.

1981-01-01

A solution assay instrument (SAI) has been developed at the Los Alamos National Laboratory and installed in the plutonium purification and americium recovery process area in the Los Alamos Plutonium Processing Facility. The instrument is designed for accurate, timely, and simultaneous nondestructive analysis of plutonium and americium in process solutions that have a wide range of concentrations and Am/Pu ratios. For a 25-mL sample, the assay precision is 5 g/L within a 2000-s count time

Rare earths and actinides

International Nuclear Information System (INIS)

Coqblin, B.

1982-01-01

This paper reviews the different properties of rare-earths and actinides, either as pure metals or as in alloys or compounds. Three different cases are considered: (i) First, in the case of 'normal' rare-earths which are characterized by a valence of 3, we discuss essentially the magnetic ordering, the coexistence between superconductivity and magnetism and the properties of amorphous rare-earth systems. (ii) Second, in the case of 'anomalous' rare-earths, we distinguish between either 'intermediate-valence' systems or 'Kondo' systems. Special emphasis is given to the problems of the 'Kondo lattice' (for compounds such as CeAl 2 ,CeAl 3 or CeB 6 ) or the 'Anderson lattice' (for compounds such as TmSe). The problem of neutron diffraction in these systems is also discussed. (iii) Third, in the case of actinides, we can separate between the d-f hybridized and almost magnetic metals at the beginning of the series and the rare-earth like the metals after americium. (orig.)

Deep-sea mud in the Pacific Ocean as a potential resource for rare-earth elements

Science.gov (United States)

Kato, Yasuhiro; Fujinaga, Koichiro; Nakamura, Kentaro; Takaya, Yutaro; Kitamura, Kenichi; Ohta, Junichiro; Toda, Ryuichi; Nakashima, Takuya; Iwamori, Hikaru

2011-08-01

World demand for rare-earth elements and the metal yttrium--which are crucial for novel electronic equipment and green-energy technologies--is increasing rapidly. Several types of seafloor sediment harbour high concentrations of these elements. However, seafloor sediments have not been regarded as a rare-earth element and yttrium resource, because data on the spatial distribution of these deposits are insufficient. Here, we report measurements of the elemental composition of over 2,000 seafloor sediments, sampled at depth intervals of around one metre, at 78 sites that cover a large part of the Pacific Ocean. We show that deep-sea mud contains high concentrations of rare-earth elements and yttrium at numerous sites throughout the eastern South and central North Pacific. We estimate that an area of just one square kilometre, surrounding one of the sampling sites, could provide one-fifth of the current annual world consumption of these elements. Uptake of rare-earth elements and yttrium by mineral phases such as hydrothermal iron-oxyhydroxides and phillipsite seems to be responsible for their high concentration. We show that rare-earth elements and yttrium are readily recovered from the mud by simple acid leaching, and suggest that deep-sea mud constitutes a highly promising huge resource for these elements.

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.

Rare-earth element geochemistry in the Luanga Mafic-Ultramafic Complex, Para

International Nuclear Information System (INIS)

Suita, M.T.F.; Nilson, A.A.

1989-01-01

Six whole-rock samples (harzburgite, orthopyroxenic and norite) of the Luanga Mafic-Ultramafic Complex (Para) were analysed for rare-earth elements (REE) through plasma spectrometry. The Luanga Complex is a deformed and metamorphosed layered mafic-ultramafic body of Archaean age. The Complex underwent medium-grade metamorphism in three stages. The first stage (medium grade) involved local formation of tremolite and reduction of Ca content in plagioclase. The second stage (low grade) consisted of serpentinization of amphibole or ortopyroxene forming bastile and generation of albite + epidote + white mica + actinolite from plagioclase. The third stage involved renewed serpentinization and/or talcification of pre-existing minerals (including serpentine) along fracture and fault surfaces. The analysed rocks display light rare-earth element (LREE) enrichment up to sixty times the composition of the Leedly chondrite and La/Yb ratios from 6.2 to 20.0 they are low in medium rare-earth elements (MREE), displaying discrete to strong negative Eu anomaly even in plagioclase cumulates and are slightly enriched in heavy rare-earth elements (HREE), usually higher than chondrite values. The low MREE area related to the occurrence of orthopyroxene (bronzite) in a way similar to the pattern of alpine periodotites, while HREE enrichment is compatible with the presence of bronzite and Mg-olivine, probably an inherited igneous feature. (author) [pt

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.

Peculiarities of extraction of carbonate complexes of trivalent transplutonium elements by alkylpyrocatechins

International Nuclear Information System (INIS)

Karalova, Z.K.; Bukina, T.I.; Myasoedov, B.F.; Fedorov, L.A.; Sokolovskij, S.A.

1987-01-01

Extraction of trivalent americium, curium, californium and europium by technical mixture of mono- and didecylpyrocatechin (TAP) in various diluents from carbonate solutions is investigated. Effect of many factors (pH, K 2 CO 3 concentration, TAP, metal; the time of phase contact) on the completeness of element isolation and separation is clarified. It is ascertained that the elements listed are quantitatively extracted by TAP solution in toluene and cyclohexane in the range of K 2 CO 3 concentrations from 0.25 to 1.5 mol/l. The difference in americium and curium distribution coefficient during their extraction by TAP from 0.25 mol/l of K 2 CO 3 solution is detected. Separation coefficients of the pair increase with the increase of carbonate solution pH. The separation can be improved at the stage of element reextraction by the mixture of K 2 CO 3 and DTPA or EDTA from alkylpyrocatechin, sunce rate constants of americium and curium reextraction differ greatly. Using 13 C NMR the composition of compounds in organic phase on the basis of 4-(α, α-dioctylethyl)pyrocatechin is investigated

Production of Rare Earth Elements from Malaysian Monazite by Selective Precipitation

International Nuclear Information System (INIS)

Che Nor Aniza Che Zainul Bahri; Al- Areqi, W.M.; Amran Abdul Majid; Mohd Izzat Fahmi Mohd Ruf

2016-01-01

Rare earth elements (REEs) are very valuable and have high demands for advanced technology nowadays. REEs can be classified to light rare earth elements (LREEs) and heavy rare earth elements (HREEs). Malaysian rare earth ore especially monazite, is rich with LREEs compared to HREEs. Therefore a study was carried out to extract the REE from Malaysian monazite. The objectives of this study are to determine the content of REEs in Malaysian monazite leach solution, as well as to produce high grade of REEs. Concentrated sulphuric acid was used in digestion process and the filtrate containing the REEs was determined using Inductively Coupled Plasma- Mass Spectrometry (ICP-MS). Ammonia solution was used for REEs precipitation from monazite leach solution. The result indicated that REEs was successfully separated from monazite leach solution through selective precipitation using ammonia at pH 2.34 and the percentage of REEs that successfully separated was 70.03 - 81.85 %. The percentage of REEs which successfully separated from final solution was 96.05 - 99.10 %. Therefore, to have high purification of individual REEs, solvent extraction process should be carried out. (author)

Direct quantification of rare earth element concentrations in natural waters by ICP-MS

International Nuclear Information System (INIS)

Lawrence, Michael G.; Greig, Alan; Collerson, Kenneth D.; Kamber, Balz S.

2006-01-01

A direct quadrupole ICP-MS technique has been developed for the analysis of the rare earth elements and yttrium in natural waters. The method has been validated by comparison of the results obtained for the river water reference material SLRS-4 with literature values. The detection limit of the technique was investigated by analysis of serial dilutions of SLRS-4 and revealed that single elements can be quantified at single-digit fg/g concentrations. A coherent normalised rare earth pattern was retained at concentrations two orders of magnitude below natural concentrations for SLRS-4, demonstrating the excellent inter-element accuracy and precision of the method. The technique was applied to the analysis of a diluted mid-salinity estuarine sample, which also displayed a coherent normalised rare earth element pattern, yielding the expected distinctive marine characteristics

Study on trace and rare earth elements in Indonesian oil sands

Energy Technology Data Exchange (ETDEWEB)

Bai, Jing-ru; Wang, Qing; Liu, Hong-peng; Bai, Zhang [Northeast Dianli Univ., Jilin (China). Engineering Research Centre

2013-07-01

Major, trace elements and rare earth and mineral composition of the oil sand samples (ST1, ST2, ST3) and the oil sand retorting residue (semi-coke: SC1, SC2, SC3) from Indonesian were determined by XFS, ICP-MS and XRD methods. The trace elements content in oil sand is pretty much the same thing in Earth's Clarke value. The trace element is abundantly in earth's Clarke, in oil sand yet, for Ti, Mn, Ba, Sr, but these elements are lower enrichment. However, the Cr (EF = 16.8) and Mo (EF = 11.8) are ''enrichment'' in ST1; the Ni (EF =10.5), Se (EF = 17.5), Sr (EF = 28.7), Mo (EF = 106.5), Sc (EF = 12.8) and U (EF = 43.2) are ''enrichment'' in ST2; the Se (EF = 12.6), Sr (EF = 18.4), Mo (EF = 47.5), and U (EF = 27.8) are ''enrichment'' in ST3. Calculations show that trace elements in sime-coke have lower evaporation rate during Fischer Assay. Trace elements in raw oil sand are so stable that trace elements can't move easily to other pyrolysis product but enrich to sime-coke. After retorting, more elements are EF > 10, such as B, V, Ni, As, Se, Sr, Mo, Hg, Cs and U. It is essential to take the pollution produced by trace elements in sime-coke during the sime-coke utilization into consideration. The REEs content had a high correlation with the ash in oil sand. The REE is closely related to terrigenous elastic rocks.

Americium/Curium Disposition Life Cycle Planning Study

International Nuclear Information System (INIS)

Jackson, W.N.; Krupa, J.; Stutts, P.; Nester, S.; Raimesch, R.

1998-01-01

At the request of the Department of Energy Savannah River Office (DOE- SR), Westinghouse Savannah River Company (WSRC) evaluated concepts to complete disposition of Americium and Curium (Am/Cm) bearing materials currently located at the Savannah River Site (SRS)

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)

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

Selective leaching studies of deep-sea sediments loaded with americium, neptunium and plutonium

International Nuclear Information System (INIS)

Cole, T.G.; Higgo, J.J.W.; Cronan, D.S.; Rees, L.V.C.

1984-07-01

A series of selective leaching experiments were undertaken to investigate the solid phase speciation and distribution of americium, neptunium and plutonium which had been experimentally loaded onto different marine sediment types. The chemical leaches employed showed rather poor selectivity but certain trends were evident. Adsorption was not by ion exchange. Americium showed a preferential affinity for carbonate and plutonium for organic matter. Neptunium appeared to have no preferential affinities. Americium was sorbed by acetic acid residues (CaCO 3 removed) and by unleached carbonate-rich sediments with equal efficiency. This indicates that it is able to diversify its solid phase affinity/distribution depending upon which solid phases are available. (author)

On the role of different biocomponents of bile and excretions in the elimination of plutonium and americium from the body

International Nuclear Information System (INIS)

Shvydko, N.S.

1986-01-01

A study was made of the role of biocomponents of bile, urine and feces in the elimination of plutonium and americium from the organism. Plutonium 239 and americium 241 were separated in bile due to higher tropism of plutonium to low molecular weight addends, and of americium, to a protein-containing fraction. The status of plutonium excreted in feces was the same as the physicochemical status of americium. Plutonium 239 and americium 241 eliminated in urine were in a completely ultrafiltered state

Mineralogy of the rare earth elements

International Nuclear Information System (INIS)

Clark, A.M.

1984-01-01

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

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)

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 vegetable had the highest 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.

Mobility of plutonium and americium through a shallow aquifer in a semiarid region

International Nuclear Information System (INIS)

Penrose, W.R.; Polzer, W.L.; Essington, E.H.; Nelson, D.M.; Orlandini, K.A.

1990-01-01

Treated liquid wastes containing traces of plutonium and americium are released into Mortandad Canyon, within the site of Los Alamos National Laboratory, NM. The wastes infiltrate a small aquifer within the canyon. Although laboratory studies have predicted that the movement of actinides in subsurface environments will be limited to less than a few meters, both plutonium and americium are detectable in monitoring wells as far as 3,390 m downgradient from the discharge. Between the first and last monitoring wells (1.8 and 3.4 km from the discharge), plutonium concentrations decreased exponentially from 1,400 to 0.55 mBq/L. Americium concentrations ranged between 94 and 1,240 mBq/L, but did not appear to vary in a systematic way with distance. Investigation of the properties of the mobile actinides indicates that the plutonium and part of the americium are tightly or irreversibly associated with colloidal material between 25 and 450 nm in size. The colloidally bound actinides are removed only gradually from the groundwater. The fraction of the americium not associated with colloids exists in a low molecular weight form (diameter, ≤ 2 nm) and appears to be a stable, anionic complex of unknown composition. The mobile forms of these actinides defeat the forces that normally act to retard their movement through groundwater systems

Uptake of rare earth elements by dryopteris erythrosora (autumn fern)

International Nuclear Information System (INIS)

Ozaki, Takuo; Enomoto, Shuichi

2001-01-01

Mechanisms of uptake of rare earth elements (REEs) were investigated, particularly those by REE accumulator species (autumn fern). Rare earth elements are practically insoluble under natural conditions, suggesting some unknown mechanisms in REE accumulator species. In the present investigation, two notable phenomena were observed. (1) Concerning the ionic-radius dependence of REE uptake by leaves, nonaccumulator species showed an extremely high uptake for Y compared with the adjacent-ionic-radius REEs in the multitracer, while accumulator species showed no anomaly. (2) REE uptake by autumn fern was influenced by the addition of chelating chemical reagents in the uptake solution, while no effect was observed for nonaccumulator species. (author)

Role of americium interference in analysis of samples containing rare earths

International Nuclear Information System (INIS)

Mohapatra, P.K.; Adya, V.C.; Thulasidas, S.K.; Bhattacharyya, A.; Kumar, Mithlesh; Godbole, S.V.; Manchanda, V.K.

2007-01-01

Quality control of nuclear fuel samples requires precise estimation of rare earths which have high neutron absorption cross sections and act as neutron poisons. Am is generated by nuclear decay where as lanthanides may be present as impurities picked up during reprocessing/fuel fabrication. Precise estimation of the rare earths by ICP-AES method in presence of 241 Am is a challenging task due to the likelihood of spectral interference of the latter. Rare earths impurities in the purified Am sample were estimated by ICP-AES method. Known amounts of the rare earths viz. Sm, Eu, Dy and Gd were used as synthetic sample and the interference due to Am was investigated. (author)

The ingestion of plutonium and americium by range cattle

International Nuclear Information System (INIS)

Blincoe, C.; Bohman, V.R.; Smith, D.D.

1981-01-01

The intake of plutonium and americium in the diet of cattle grazing on plutonium contaminated desert range was determined. Daily feed intake of the grazing animals was also determined so that the amount of nuclides ingested daily could be ascertained. Soil ingested by range cattle constituted the principal and possibly only source of ingested plutonium and americium and resulted in a daily intake of 3600-6600 pCi 238 Pu, 85,000-400,000 pCi 239 Pu, and 11,000-31,000 pCi 241 Am daily. Determining transuranic intake by direct measurement and from the composition and contamination of the diet gave identical results. (author)

Game meat authentication through rare earth elements fingerprinting.

Science.gov (United States)

Danezis, G P; Pappas, A C; Zoidis, E; Papadomichelakis, G; Hadjigeorgiou, I; Zhang, P; Brusic, V; Georgiou, C A

2017-10-23

Accurate labelling of meat (e.g. wild versus farmed, geographical and genetic origin, organic versus conventional, processing treatment) is important to inform the consumers about the products they buy. Meat and meat products declared as game have higher commercial value making them target to fraudulent labelling practices and replacement with non-game meat. We have developed and validated a new method for authentication of wild rabbit meat using elemental metabolomics approach. Elemental analysis was performed using rapid ultra-trace multi-element measurement by inductively coupled plasma mass spectrometry (ICP-MS). Elemental signatures showed excellent ability to discriminate the wild rabbit from non-wild rabbit meat. Our results demonstrate the usefulness of metabolic markers -rare earth signatures, as well as other trace element signatures for game meat authentication. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Rare earth elements and permanent magnets (invited)

Science.gov (United States)

Dent, Peter C.

2012-04-01

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

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.

Measurement of total alpha activity of neptunium, plutonium, and americium in highly radioactive Hanford waste by iron hydroxide precipitation and 2-heptanone solvent extraction

International Nuclear Information System (INIS)

Maiti, T.C.; Kaye, J.H.

1992-06-01

An improved method has been developed to concentrate the major alpha-emitting actinide elements neptunium, plutonium, and americium from samples with high salt content such as those resulting from efforts to characterize Hanford storage tank waste. Actinide elements are concentrated by coprecipitation of their hydroxides using iron carrier. The iron is removed by extraction from 8M HCI with 2-heptanone. The actinide elements remain in the aqueous phase free from salts, iron, and long-lived fission products. Recoveries averaged 98 percent

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.

Advances in the hydrometallurgical separation techniques of high purity rare earth elements

International Nuclear Information System (INIS)

Vijayalakshmi, R.; Kain, V.

2017-01-01

Rare Earths are a series of 15 chemically similar elements that occur together in monazite mineral found in the beach sands of Kerala, Tamil Nadu and Orissa. The rare earth elements (REE) are becoming increasingly strategically important considering their essential role in permanent magnets such as, SmCo_5, Sm_2Co_1_7 and Nd_2Fe_1_4B, phosphors for LED screens and lamps, rechargeable nickel metal hydride batteries and catalysts and other green applications. The increasing popularity of hybrid and electric cars, wind turbines and compact fluorescent lamps is causing an increase in the demand and price of REE. The European Commission considers the REE as the most critical raw materials group, with the highest supply risk. According to the medium-term criticality matrix of the U.S. Department of Energy (DOE), the five most critical REE are neodymium (Nd), europium (Eu), terbium (Tb), dysprosium (Dy) and yttrium (Y). China is presently producing more than 90% of all rare earths, although they possess less than 405 of the proven reserves. Due to large and increasing domestic demands, China tightened its REE export quota from 2012 onwards. These export quotas caused serious problems for REE users outside of China. Fortunately India is blessed with large resources of rare earths in the form of monazite found in the beach sands of Kerala, Tamil Nadu and Orissa. Indian Rare Earths Limited at Aluva near Kochi produces mainly mixed rare earths chloride and till recent past exporting to USA, UK, France, Japan, etc. They have revived their rare earth separation plant to meet the in-house demands of the strategic, defense and nuclear industry. This paper discusses the recent advances made in hydrometallurgical separation techniques based on solvent extraction technique, ion-exchange resins, hollow fibre membrane extractor, solvent encapsulated polymeric beads, etc for the production of high purity rare earth elements from both primary (Monazite, xenotime) and secondary sources

The availability of plutonium and americium in Irish Sea sediments for re-dissolution

International Nuclear Information System (INIS)

McDonald, P.; Vives i Batlle, J.; Bousher, A.; Whittall, A.; Chambers, N.

2001-01-01

The availability of plutonium and americium, for re-dissolution from offshore sediments into Irish Sea water, has been examined. Sediments collected from the mud-patch near the Cumbrian coast were characterized in terms of spatial location, particle size, partitioning of radionuclides with respect to physico-chemical bonds and availability of actinides for release into seawater. Sequential extraction investigations revealed that plutonium was predominantly associated with strongly bound sesquioxide and organic complex fractions. Americium was associated mainly with the organic complex fraction, but a significant fraction was in carbonate form. Sediment/water re-dissolution experiments with and without stirring were compared to simulate the effect of disturbing bed sediment. After 1 week, neither set of re-dissolution data provided significant trends between dissolved activity and time. Stirred systems appeared to release 2.5 times more plutonium and americium into seawater than unstirred systems. Measured 239,240Pu and 241Am distribution coefficients (K d values) were both typically approximately 10 5 l kg -1 . 241Am K d values are an order of magnitude lower than previously reported for the north-eastern Irish Sea, but similar to western Irish Sea values. Overall, the fractions of plutonium and americium available for re-dissolution from bed sediment are very low at <0.1%, with proportionally more plutonium being released than americium. These findings lend further support for the extrapolation of laboratory-derived information to environmental conditions

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)

Accumulation of americium-241 in the biomass of aquatic plants of the Yenisei river: experimental study

International Nuclear Information System (INIS)

Zotina, T.A.; Bolsunovsky, A.Y.A.; Bondareva, L.G.

2004-01-01

Due to the operation of the Mining-and-Chemical Combine (Krasnoyarsk-26), which has been manufacturing weapons-grade plutonium for several decades, the Yenisei River is contaminated with transuranic elements (including 241 Am). 241 Am was found in the riverside soil, sediment and in the biomass of aquatic plants (Bolsunovsky et al., 1999, 2002). Aquatic plants are an important link in the migration of radionuclides in an aquatic ecosystem. In laboratory experiments, we investigated accumulation of 241 Am by the submerged macrophyte from the Yenisei River: the pond weed (Elodea canadensis) and the aquatic moss (Fontinalis antipyretica), and release of 241 Am from the biomass. The content of 241 Am was measured on a Canberra (USA) gamma-spectrometer. The experiments showed that specific accumulation and concentration factors of 241 Am in the plants were in inverse proportion to their biomass. We obtained new data on release of 241 Am from the biomass of macrophyte. Americium-241 was more firmly fixed in the biomass of the aquatic moss. In 12 months, the biomass of the aquatic moss released about 30% of the initial americium activity into the water. To compare, the biomass of the pond weed released into the water medium up to 64% of the initial 241 Am activity in 1.5 4 months. The release rate was dependent on the decomposition rate of the plant biomass. The experiments showed that submerged macrophyte of the Yenisei River can accumulate considerable activities of 241 Am and retain americium for long periods of time in biomass. (author)

Biokinetic study of plutonium and americium associated to the particulates of soil

International Nuclear Information System (INIS)

Espinosa, A.; Aragon, A.; Martinez, J.; Iranzo, C.E.

1996-01-01

The object of this study is to determine the biokinetic parameters of different Plutonium isotopes and Americium inhaled in the state in which they are found in the environment as a result of their deposition in the soil, from an aviation accident that generated different plutonium oxides. to achieve this objective, two lines of work planned. One was the determination of the mineralogical composition and associations that plutonium and americium present in that soil 22 years after the nuclear accident. Other studies were directed to determine the biokinetic of the plutonium isotopes and americium (contained in the dust) deposited tracheally and inhaled by laboratory animals (rats) and in vitro experiments by pulmonary leaching simulation. The in vivo tests have been developed in NRPB (U.K.) and the in vitro experiment, geochemical associations studies, assessment of internal doses to humans resulting from intake of plutonium and americium bearing dusts present in the contaminated area and establishment of ALIs for inhalation, were carried out in CIEMAT (Spain). In this work only determinations and experiments carried out by CIEMAT are includes as a part of the EU Project ''INHALATION AND INGESTION OF RADIONUCLIDES'' contract: FI3P-CT920064a. (Author) 10 refs

Determination of specific activity of americium and plutonium in selected environmental samples

International Nuclear Information System (INIS)

Trebunova, T.

1999-01-01

The aim of this work was development of method for determination of americium and plutonium in environmental samples. Developed method was evaluated on soil samples and after they was applied on selected samples of fishes (smoked mackerel, herring and fillet from Alaska hake). The method for separation of americium is based on liquid separation with Aliquate-336, precipitation with oxalic acid and using of chromatographic material TRU-Spec TM .The intervals of radiochemical yields were from 13.0% to 80.9% for plutonium-236 and from 10.5% to 100% for americium-241. Determined specific activities of plutonium-239,240 were from (2.3 ± 1.4) mBq/kg to (82 ± 29) mBq/kg, the specific activities of plutonium-238 were from (14.2 ± 3.7) mBq/kg to (708 ± 86) mBq/kg. The specific activities of americium-241 were from (1.4 ± 0.9) mBq/kg to (3360 ± 210) mBq/kg. The fishes from Baltic Sea as well as from North Sea show highest specific activities then fresh-water fishes from Slovakia. Therefore the monitoring of alpha radionuclides in foods imported from territories with nuclear testing is recommended

1976 Hanford americium exposure incident: psychological aspects

International Nuclear Information System (INIS)

Brown, W.R.

1982-01-01

Accidents involving exposure to radiation or radioactive materials may involve an unusual degree of emotional trauma. Methods that may be employed in dealing with such trauma are discussed in relation to a specific accident in which a radiation worker was injured and seriously contaminated with americium-241

Influence of organic components on plutonium and americium speciation in soils and soil solutions

International Nuclear Information System (INIS)

Sokolik, G.A.; Ovsyannikova, S.V.; Kimlenko, I.M.

2003-01-01

Group composition of humic substances of organic and mineral soils sampled in the 30-km zone of the Chernobyl accident was analyzed for studying influence of organic components on migration properties of plutonium and americium in soils and soil solutions by the method of gel-chromatography and chemical fractionation. It was ascertained that humus of organic soils binds plutonium and americium stronger than humus of mineral soils. Elevated mobility of americium compared to plutonium one stems from lower ability of the latter to from hard to solve organic and organomineral complexes, as well as from its ability to form anionic complexes in soil solutions [ru

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

International Nuclear Information System (INIS)

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

2007-01-01

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

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)

Acid pressure leaching of a concentrate containing uranium, thorium and rare earth elements

International Nuclear Information System (INIS)

Lan Xinghua; Peng Ruqing.

1987-01-01

The acid pressure leaching of a concentrate containing rinkolite for recovering uranium, thorium and rare earth elements is described. The laboratory and the pilot plant test results are given. Under the optimum leaching conditions, the recovery of uranium, thorium and rare earth elements are 82.9%, 86.0% and 88.3% respectively. These results show that the acid pressure leaching process is a effective process for treating the concentrate

Carbamoyl methylphosphine oxide derivatives of adamantane as americium and europium extractants

International Nuclear Information System (INIS)

Babain, V.A.; Alyapyshev, M.Yu.; Novakov, I.A.; Orlinson, B.S.; Savel'ev, E.N.; Shokova, Eh.A.; Serebrayannikova, A.E.; Kovalev, V.V.

2007-01-01

Adamantane di-1,3-carbamoyl methylphosphine oxide (CMPO) derivatives, where CMPO-groups connect with 1,3-positions of rigid adamantane platform by methylene and ethylene bridges, are synthesized, and their efficiency as extractants of americium(III) and europium(III) from nitric acid solutions is demonstrated. Distribution function of Am 3+ and Eu + during extraction from 3M HNO 3 are measured in the investigation of extraction properties. It is noted that first synthesized adamantane CMPO derivatives are more effective for the extraction of americium(III) and europium(III) from 3MHNO 3 [ru

Radiation protection data sheets for the use of Americium 241 in unsealed sources

International Nuclear Information System (INIS)

Anon.

1993-01-01

This radiation protection data sheet is intended for supervisors and staff in the different medical, hospital, pharmaceutical, university and industrial laboratories and departments where Americium 241 is handled, and also for all those involved in risk prevention in this field. It provides essential data on radiation protection measures during the use of Americium 241 in unsealed sources: physical characteristics, risk assessment, administrative procedures, recommendations, regulations and bibliography

Adsorption-desorption characteristics of plutonium and americium with sediment particles in the estuarine environment: studies using plutonium-237 and americium-241

International Nuclear Information System (INIS)

Murray, C.N.; Fukai, R.

1975-01-01

The particle formation of plutonium and americium, their adsorption onto fresh water sediments and the desorption from the sediments in sea water were studied in the Laboratory under simulated river-estuary conditions, using γ-emitting plutonium-237 and americium-241. The results of the experiments show that the particle formation of plutonium depends on its valence states, on pH and on the salinity of the medium. For river water at pH4, some 25%, 20% and 30% of the added 237 Pu was in particulate form, larger than 0.45 μm, for Pu (III), Pu (IV) and Pu (VI), respectively, while 65%, 90% and 50% of the respective valence states was associated with particles at pH 8. In sea water the general pattern remains similar, although Pu (VI) is more soluble in sea water owing to higher ligand concentrations for carbonate and bicarbonate complexes. The pH-dependency of particle formation of Am (III) is more steep than that of plutonium and seems to be influenced by colloidal substances occurring in the experimental media. The adsorption-desorption characteristics of plutonium and americium with the sediment in river water as well as sea water reflect the characteristics of their particle formation, being dependent upon such properties as valence states, the pH and salinity of the medium. A sewage effluent added to the media has small but measurable effects on the adsorption-desorption processes of plutonium. (author)

Local Structure in Americium and Californium Hexa-cyanoferrates - Comparison with Their Lanthanide Analogues

International Nuclear Information System (INIS)

Dupouy, G.; Bonhoure, I.; Dumas, Th.; Moisy, Ph.; Petit, S.; Den Auwer, Ch.; Conradson, St.D.; Hennig, Ch.; Scheinost, A.C.; Le Naour, C.; Simoni, E.

2011-01-01

Metal hexa-cyanoferrates are well known molecular solids for a large variety of cations, although very little has been described for actinide adducts. Two new members of actinide(III) hexa-cyanoferrates were synthesized with the cations americium and californium. They were structurally characterized by infrared and X-ray absorption spectroscopy. Combined EXAFS data at the iron K edge and actinide L 3 edge provide evidence for a three-dimensional model for these two new compounds. Structural data in terms of bond lengths were compared to those reported for the parent lanthanide(III) compounds, neodymium and gadolinium hexa-cyanoferrates, respectively: the americium compound with (KNd(III)Fe(II)-Fe-III(CN) 6 .4H 2 O and the californium compound with (KGd(III)Fe(II)(CN) . 3.5H 2 O and (KGd(III)Fe(II)(CN) 6 .3H 2 O. This comparison between actinide and lanthanide homologues has been carried out on the basis of ionic radii considerations. The americium and neodymium environments appear to be very similar and are arranged in a tri-capped trigonal prism polyhedron of coordination number 9 (CN: 9), in which the americium atom is bonded to six nitrogen atoms and to three water molecules. For the californium adduct, a similar comparison and bond length and angle values derived from EXAFS studies suggest that the californium cation sits in a bi-capped trigonal prism (CN: 8) as in (KGd(III)Fe(II)(CN) 6 . 3H 2 O. This arrangement differs from that in the structure of (KGd(III)Fe(II)(CN) 6 .3.5H 2 O, in which the gadolinium atom is surrounded by 9 atoms. This is one of the rare pieces of information revealed by EXAFS spectroscopy for americium and californium in comparison to lanthanide atoms in molecular solid compounds. A discussion on the decrease in bond length and coordination number from americium to californium is also provided, on the basis of crystallographic results reported in the literature for actinide(III) and lanthanide(III) hydrate series. (authors)

Determination of rare earth elements in rice by INAA and ICP-MS

International Nuclear Information System (INIS)

Pham Thi Huynh, M.; Chu Pham Ngoc, S.; Carrot, F.; Revel, G.; Dang Vu, M.

1997-01-01

Irrigation of rice plants with a solution of rare earth elements increases both the production capacity and the resistance to disease. Assuming that the treated plants remain expendable, the different parts of plants, root stalk and grain, were analyzed by instrumental neutron activation analysis (INAA) and by mass spectrometry after plasma excitation (ICP-MS). About 40 elements were determined. The results showed that the contamination remained in the roots and was absent in rice grains. The analytical distribution of different elements in different parts of both treated and non-treated plants has given some information concerning the possible effect of the rare earth treatment. The performances of the two analytical methods have been compared. (author)

Study of polyoxide catalysts of methane combustion on Mn, Cu, Ni, rare earth elements, alkaline earth elements base by the X-ray fluorescence analysis method

International Nuclear Information System (INIS)

Grigor'eva, V.P.; Popova, N.M.; Zheksenbaeva, Z.T.; Sass, A.S.; Salakhova, R.Kh.; Dosumov, K.D.

2002-01-01

The results of X-ray fluorescence analysis of polyoxide catalysts on of Mn, Cu, Ni, rare earth elements, alkaline earth elements base supported on 2 % Ce/θ-Al 2 O 3 are presented. This polyoxide catalysts are using for deep methane oxidation. DRON-4-7 X-ray diffractometers was applied for the analysis. It was found, that oxides in Ni-Cu-Cr catalysts after long time heating up to 1200 deg. C have been interacted with catalyst supports with Ni(Cu)Al 2 O 3 aluminates formation and due to its decomposition transformation degree of CH 4 to CO 2 are reduced. Activity of MnBaSrCeLa catalysts after heating up to 1200 deg. C does not changed

Determination of rare earth elements in aluminum by inductively coupled plasma-atomic emission spectroscopy

International Nuclear Information System (INIS)

Mahanti, H.S.; Barnes, R.M.

1983-01-01

Inductively coupled plasma-atomic emission spectroscopy is evaluated for the determination of 14 rare earth elements in aluminum. Spectral line interference, limit of detection, and background equivalent concentration values are evaluated, and quantitative recovery is obtained from aluminum samples spiked with rare earth elements. The procedure is simple and suitable for routine process control analysis. 20 references, 5 tables

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.

Element Abundances in Meteorites and the Earth: Implication for the Accretion of Planetary Bodies

Science.gov (United States)

Mezger, K.; Vollstaedt, H.; Maltese, A.

2017-12-01

Essentially all known inner solar system materials show near chondritic relative abundances of refractory elements and depletion in volatile elements. To a first approximation volatile element depletion correlates with the respective condensation temperature (TC) of the elements. Possible mechanisms for this depletion are incomplete condensation and partial loss by evaporation caused by heating prior to or during the planetesimal accretion. The stable isotope compositions of almost all moderately volatile elements in different meteorite classes show only minor, or no evidence for a Rayleigh-type fractionation that could be attributed to partial condensation or evaporation. The different classes of meteorites also show that the degree of depletion in their parent bodies (i.e. mostly planetesimals) is quite variable, but nevertheless systematic. For primitive and least disturbed carbonaceous chondrites the element depletion pattern is a smooth function of TC. The accessible silicate Earth also shows this general depletion pattern, but in detail it is highly complex and requires differentiation processes that are not solely controlled by TC. If only highly lithophile elements are considered the depletion pattern of the silicate Earth reveals a step function that shows that moderately volatile lithophile elements have abundances that are ca. 0.1 times the chondritic value, irrespective of their TC. This element pattern observed for bulk silicate Earth can be modelled as a mixture of two distinct components: ca. 90% of a strongly reduced planetary body that is depleted in highly volatile elements and ca. 10% of a more volatile element rich and oxidized component. This mixture can account for the apparent Pb- paradox observed in melts derived from the silicate Earth and provides a time constraint for the mixing event, which is ca. 70 My after the beginning of the solar system. This event corresponds to the giant impact that also formed the Moon.

1976 Hanford americium exposure incident: overview and perspective

International Nuclear Information System (INIS)

Thompson, R.C.

1982-01-01

Salient features of the 1976 Hanford americium exposure incident are discussed. Comparisons are made with previous human and animal exposure data, and conclusions drawn relative to the injured workman, to health physics practices, and to the adequacy of current exposure limits

Annual report for FY 1976 on project AN0115A: the migration of plutonium and americium in the lithosphere

International Nuclear Information System (INIS)

Fried, S.; Friedman, A.M.; Hines, J.J.; Atcher, R.W.; Quarterman, L.A.; Volesky, A.

1976-12-01

Studies have been carried out on the migration of plutonium and americium in solutions flowing through porous and crushed rock and through fissures. The migration process can be described in terms of the surface absorption of these elements. In addition, chemical effects on the absorption have been observed. One of these effects is possibly due to the presence of a plutonium polymer that migrates at a more rapid rate than normal plutonium

Determination of the rare earth elements in marine pore waters and associated sediments

International Nuclear Information System (INIS)

Kennedy, H.; Elderfield, H.

Accurate and precise determinations of natural levels of rare earth elements (R.E.E.) in sea water and pore water are highly reliant upon the size and variability of the analytical blank, the method for determining the yield, and, to a lesser extent, the inherent precision of the instrument used. Isotope dilution mass spectrometry (IDMS) together with ultra-clean room techniques has been successfully used in the determinations of rare earth elements in pore waters. Simultaneous multi-element analysis by inductively coupled plasma atomic emission spectrometry (ICP) provides an alternative to IDMS for a rapid determination of R.E.E. in sediments. (author)

Effect of rare earth elements on the distribution of photosynthate in sugar beet

International Nuclear Information System (INIS)

Bai Baozhang; Yang Yuchang; Meng Xianju; Wang Yuefeng; Bai Song

1995-01-01

The effect of rare earth elements on the distribution of photosynthate in sugar beet was studied. The results indicated that rare earth elements stimulated CO 2 assimilation, increased the ratio of root and tops (R/T), improved the distribution of photosynthate and stimulated the transport of organic matter from leaf to root of sugar beet plant. The treatment with 0.05% was shown to have the most significant effect among all the treatments

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

Determination of individual rare earth elements in Vietnamese monazite by radiochemical neutron activation analysis

International Nuclear Information System (INIS)

Nguyen Van Suc; Nguyen Mong Sinh

1993-01-01

Radiochemical neutron activation analysis (RNAA) has been applied for determination of rare earth elements (REE) in Vietnamese monazite. The chemical separation procedure used is based on the chromatographic elution of rare earth groups, after the separation of 233 Pa(Th) in irradiated monazite samples by coprecipitation with MnO 2 , the rare earth elements were retained by Biorad AG1 x 8 resin column in 10% 15.4M HNO 3 -90% methanol solution. The elution of heavy rare earth (HREE) and middle rare earth (MREE) groups was carried out with 10% 1M HNO 3 - 90% methanol and 10% 0.05M HNO 3 -90% methanol solution, respectively; while the light rare earths (LREE) were eluted from the column by 0.1M HNO 3 solution. The accuracy of the method was checked by the analysis of granodiorite GSP-I and the rare earth values were in good agreement. (author) 7 refs.; 3 tabs

Maria Goeppert Mayer's Theoretical Work on Rare-Earth and Transuranic Elements

OpenAIRE

Wang, Frank Y.

2008-01-01

After the discovery of element 93 neptunium by Edwin McMillan and Philip H. Abelson in 1941, Maria Goeppert Mayer applied the Thomas-Fermi model to calculate the electronic configuration of heavy elements and predicted the occurrence of a second rare-earth series in the vicinity of elements 91 or 92 extending to the transuranic elements. Mayer was motivated by Enrico Fermi, who was at the time contemplating military uses of nuclear energy. Historical development of nuclear science research le...

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.)

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...

Accumulation of americium-241 in the biomass of aquatic plants of the Yenisei river: experimental study

Energy Technology Data Exchange (ETDEWEB)

Zotina, T.A.; Bolsunovsky, A.Y.A.; Bondareva, L.G. [Institute of Biophysics SB RAS, Akademgorodok, Krasnoyarsk (Russian Federation)

2004-07-01

Due to the operation of the Mining-and-Chemical Combine (Krasnoyarsk-26), which has been manufacturing weapons-grade plutonium for several decades, the Yenisei River is contaminated with transuranic elements (including {sup 241}Am). {sup 241}Am was found in the riverside soil, sediment and in the biomass of aquatic plants (Bolsunovsky et al., 1999, 2002). Aquatic plants are an important link in the migration of radionuclides in an aquatic ecosystem. In laboratory experiments, we investigated accumulation of {sup 241}Am by the submerged macrophyte from the Yenisei River: the pond weed (Elodea canadensis) and the aquatic moss (Fontinalis antipyretica), and release of {sup 241}Am from the biomass. The content of {sup 241}Am was measured on a Canberra (USA) gamma-spectrometer. The experiments showed that specific accumulation and concentration factors of {sup 241}Am in the plants were in inverse proportion to their biomass. We obtained new data on release of {sup 241}Am from the biomass of macrophyte. Americium-241 was more firmly fixed in the biomass of the aquatic moss. In 12 months, the biomass of the aquatic moss released about 30% of the initial americium activity into the water. To compare, the biomass of the pond weed released into the water medium up to 64% of the initial {sup 241}Am activity in 1.5 4 months. The release rate was dependent on the decomposition rate of the plant biomass. The experiments showed that submerged macrophyte of the Yenisei River can accumulate considerable activities of {sup 241}Am and retain americium for long periods of time in biomass. (author)

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

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.)

Kinetics of americium(VI) mass transfer through solid supported liquid membrane with HDEHP

International Nuclear Information System (INIS)

Mikheeva, M.N.; Novicoov, P.; Myasoedov, B.F.; Tikhomirov, S.V.

1994-01-01

The main regularities of membrane extraction of americium under conditions of different redox potentials in aqueous phases have been studied. The physico-chemical model of the process including steps of americium oxidation in feed solution, extraction by membrane, partial reduction on membrane surface, trans-membrane diffusion and reextraction to strip solution has been developed. The calculation of reduction rate constant on membrane surface has been carried out. (author) 9 refs.; 4 figs.; 3 tabs

Incorporation of natural radionuclides and rare earth element into a salt tolerant plant

International Nuclear Information System (INIS)

Summerton, A.P.

1992-01-01

A highly salt tolerant shrub, samphire (Halosarcia halocnemoides), found growing in the solid alkaline residues in an evaporation pond at a former uranium and monazite treatment plant, has been analysed for natural radionuclides and rare earths. The data obtained have been copared with that for plants from the local natural environment. Vegetation-to-soil concentration ratios have been determined. The radionuclide concentration ratios for samples from the contaminated site are similar to those from the natural environment. Significant differences have been noted in the case of the rare earth elements with an apparent preferential incorporation of the light rare earth elements into the plant growing in the chemical residues. (author) 10 refs.; 1 fig.; 2 tabs

Generalized phase diagram for the rare-earth elements: Calculations and correlations of bulk properties

International Nuclear Information System (INIS)

Johansson, B.; Rosengren, A.

1975-01-01

A ''generalized'' phase diagram is constructed empirically for the lanthanides. This diagram makes it possible, not only in one picture, to assemble a lot of information but also to predict phase transitions not yet experimentally accessible. Further, it clearly illustrates the close relation between the members of the lanthanide group. To account for some of its features, the pseudopotential method is applied. The trend in crystal structure through the lanthanide series can thereby be qualitatively accounted for, as can the trend in crystal structure for an individual element, when compressed. A scaling procedure makes it possible to extend the treatment to elements neighboring the lanthanides in the Periodic Table. In total 25 elements are considered. An atomic parameter f (relatable to the pseudopotential) is introduced, by means of which different phase transitions, both for an individual rare-earth element and intra-rare-earth alloys, can be correlated to certain critical values of this parameter. A nonmagnetic rare-earth series (Sc, Lu, Y, La, and Ac) is introduced and the occurrence of superconductivity is discussed with special emphasis on the pressure dependence of the transition temperature. This temperature can be correlated to the above-mentioned parameter f, both for intra-rare-earth alloys and pure elements at different pressures. The correlation implies that actinium is a superconductor with a critical temperature which could be as high as (11--12) degree K

Airborne plutonium-239 and americium-241 concentrations measured from the 125-meter Hanford Meteorological Tower

International Nuclear Information System (INIS)

Sehmel, G.A.

1978-01-01

Airborne plutonium-239 and americium-241 concentrations and fluxes were measured at six heights from 1.9 to 122 m on the Hanford meteorological tower. The data show that plutonium-239 was transported on nonrespirable and small particles at all heights. Airborne americium-241 concentrations on small particles were maximum at the 91 m height

Environmental impacts of the release of a transuranic actinide, americium-241, from a contaminated facility

Energy Technology Data Exchange (ETDEWEB)

Want, J.; Merry-Libby, P.

1985-10-29

Americium-241 is widely used as a radiation source, but it also has some potential risk if taken into the body because of its high dose conversion factor. Although the radiotoxicity of americium-241 is small compared to other transuranic actinides, its effects on the reproductive system and on development of the placenta are more damaging than the effects of plutonium-239. In Ohio, a gemologist's laboratory was contaminated with americium-241. Prior to decontamination of the laboratory, potential radiological impacts to the surrounding environment were assessed. A hypothetical fire accident resulting in a unit release (1 curie) was assumed. Potential radiological impacts were simulated using an atmospheric dispersion and dosimetry model with local meteorological data, population census data, and detailed information regarding the neighborhood. The results indicate that there could have been a significant impact on nearby residents from americium-241 via atmospheric dispersion if a major catastrophic release had occurred prior to contamination and decommissioning of the laboratory. 14 refs., 3 figs., 2 tabs.

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)

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)

Airborne plutonium and americium concentrations measured from the top of Rattlesnake Mountain

International Nuclear Information System (INIS)

Sehmel, G.A.

1979-01-01

Airborne plutonium-239+240 and americium-241 blowing from offsite was measured in an initial experiment at the top of Rattlesnake Mountain. Average airborne concentration measured was similar to fallout concentrations. Airborne plutonium concentrations were independent of wind speed for seven wind speed increments between 0.5 and 31 m/sec. In contrast the airborne americium concentration was a minimum at a wind speed of approximately 7 m/sec. Similarly, the airborne solids concentration in μg/m 3 was a minimum at an intermediate wind speed increment of 7 to 11 m/sec

Distribution characteristics of rare earth elements in plants from a rare earth ore area

International Nuclear Information System (INIS)

Zhang, Z.Y.; Wang, Y.Q.; Li, F.L.; Xiao, H.Q.; Chai, Z.F.

2002-01-01

The contents of eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in various plant species taken from a rare earth ore area were determined by instrumental neutron activation analysis. For a given plant, the REE patterns in root, leaf and host soil are different from each other. The REE distribution characteristics in roots of various species are very similar and resemble those in the surface water. The results of this study suggest that there is no significant fractionation between the REEs during their uptake by the plant roots from soil solution. However, the variation of the relative abundance of individual REE occurs in the process of transportation and deposition of REEs in plants. (author)

An experimental investigation of accumulation and transmutation behavior of americium in the MOX fuel irradiated in a fast reactor

International Nuclear Information System (INIS)

Osaka, Masahiko; Koyama, Shin-ichi; Maeda, Shigetaka; Mitsugashira, Toshiaki

2005-01-01

Americium isotopes generated in the MOX fuel irradiated in the experimental fast reactor JOYO were analyzed by applying a sophisticated radiochemical technique. Americium was isolated from the irradiated MOX fuel by a combined method of anion-exchange chromatography and oxidation of Am. The isotopic ratios of americium and its content were determined by thermal ionization mass spectroscopy and α-spectrometry, respectively. The americium isotopic ratio was similar for all the specimens, but was significantly different from that of PWR-MOX. On the basis of present analytical results, the accumulation and transmutation behavior of americium nuclides in a fast reactor is discussed from the viewpoints of neutron spectrum dependence and the isomeric ratio of the 241 Am capture reaction. The estimated isomeric ratio is about 87%, which is close to the latest evaluated value. A rapid estimation method of Am content by using the 240 Pu to 239 Pu ratio was adopted and proved to be valid for the spent fuel irradiated in the fast reactor

Rare earths: critical elements for various applications and challenges in their separation

International Nuclear Information System (INIS)

Singh, D.K.; Chakravartty, J.K.

2015-01-01

High purity rare earths oxides, metal and alloys find wide applications in high tech area such as nuclear energy, permanent magnets, materials for storing hydrogen, phosphors, laser, etc. Rare earths consists a group of 15 elements from La to Lu in the periodic table and it also includes Sc and Y. Due to similar chemical nature owing to common oxidation state of +3, rare earths are very difficult to separate from each other. They have very low separation factors with acidic extractants like D2EHPA and EHEHPA and hence require large number of stages in various cascade of extraction process. Monazite (a source of rare earths, thorium and uranium) is processed at IREL to separate rare earths from thorium and uranium. The rare earths are fractionated into three groups namely light rare earths (LRE), middle rare earths (MRE) and heavy rare earths (HRE) by solvent extraction method employing EHEHPA as extractant

The transfer of rare earth elements through liquid extraction membranes

International Nuclear Information System (INIS)

Kapranchik, V.P.; Proyaev, V.V.; Kopyrin, A.A.

1988-01-01

The transfer of rare earth elements through liquid extraction membranes, presenting Dacron nuclear filters, impregnated by extractants of different types (tributylphosphine oxide; di-2-ethylhexylphosphoric acid, HDEHP; trioctylamine, TOA) is investigated. It is ascertained that in systems with extractant-carriers TOA and HDEHP inversion of dependences of flow values and distribution coefficients on the element atomic number is observed. Mathematical model of transfer, permitting to establish relation between extractional and transport characteristics of the membrane, is suggested

Experimental studies to validate model calculations and maximum solubility limits for Plutonium and Americium; Experimentelle Arbeiten zur Absicherung von Modellrechnungen und Maximalkonzentrationen fuer Plutonium und Americium

Energy Technology Data Exchange (ETDEWEB)

NONE

2017-02-16

This report focuses on studies of KIT-INE to derive a significantly improved description of the chemical behaviour of Americium and Plutonium in saline NaCl, MgCl{sub 2} and CaCl{sub 2} brine systems. The studies are based on new experimental data and aim at deriving reliable Am and Pu solubility limits for the investigated systems as well as deriving comprehensive thermodynamic model descriptions. Both aspects are of high relevance in the context of potential source term estimations for Americium and Plutonium in aqueous brine systems and related scenarios. Americium and Plutonium are long-lived alpha emitting radionuclides which due to their high radiotoxicity need to be accounted for in a reliable and traceable way. The hydrolysis of trivalent actinides and the effect of highly alkaline pH conditions on the solubility of trivalent actinides in calcium chloride rich brine solutions were investigated and a thermodynamic model derived. The solubility of Plutonium in saline brine systems was studied under reducing and non-reducing conditions and is described within a new thermodynamic model. The influence of dissolved carbonate on Americium and Plutonium solubility in MgCl{sub 2} solutions was investigated and quantitative information on Am and Pu solubility limits in these systems derived. Thermodynamic constants and model parameter derived in this work are implemented in the Thermodynamic Reference Database THEREDA owned by BfS. According to the quality assurance approach in THEREDA, is was necessary to publish parts of this work in peer-reviewed scientific journals. The publications are focused on solubility experiments, spectroscopy of aquatic and solid species and thermodynamic data. (Neck et al., Pure Appl. Chem., Vol. 81, (2009), pp. 1555-1568., Altmaier et al., Radiochimica Acta, 97, (2009), pp. 187-192., Altmaier et al., Actinide Research Quarterly, No 2., (2011), pp. 29-32.).

Rare-earth elements in uranium deposits in the municipality of Pedra, Pernambuco, Brazil

International Nuclear Information System (INIS)

Kennedy Francys Rodrigues Damascena; Romilton dos Santos Amaral; Jose Araujo dos Santos Junior; Alberto Antonio da Silva; Romulo Simoes Cezar Menezes

2015-01-01

In the present study, soil and rock samples were collected from uranium deposits in the city of Pedra, Pernambuco, Brazil. These samples were analyzed using neutron activation analysis to identify the occurrence of rare-earth elements (REE). The most abundant elements found were Ce, Nd and La, with concentrations 12 times higher than the average in the earth's crust and 4.6 times higher than values reported in worldwide studies, including Brazil. Nonetheless, further studies to examine the economic feasibility of mining REEs from this site are necessary. (author)

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.

Molecular localisation of americium, technetium and cesium in edible marine animals. Their metabolic behavior and their consequences; Localisation moleculaire de l'americium, du technetium et du cesium chez des animaux marins comestibles leur comportement metabolique et ses consequences

Energy Technology Data Exchange (ETDEWEB)

Pieri, J; Goudard, F; Milcent, M C [Laboratoire de Biochimie et Radiochimie, Faculte des Sciences et des Techniques, Nantes Cedex (France)

1992-07-01

We show the molecular behavior of americium, technetium and cesium on the chromatographic pattern of each cytosol in the digestive gland of eel and lobster. The contamination by cadmium seems to compete with americium in the fractions of MW 10,000. Cesium shows an ionic behavior. (author)

Determination of rare earth elements in high purity rare earth oxides by liquid chromatography, thermionic mass spectrometry and combined liquid chromatography/thermionic mass spectrometry

International Nuclear Information System (INIS)

Stijfhoorn, D.E.; Stray, H.; Hjelmseth, H.

1993-01-01

A high-performance liquid chromatographic (HPLC) method for the determination of rare earth elements in rocks has been modified and used for the determination of rare earth elements (REE) in high purity rare earth oxides. The detection limit was 1-1.5 ng or 2-3 mg/kg when a solution corresponding to 0.5 mg of the rare earth oxide was injected. The REE determination was also carried out by adding a mixture of selected REE isotopes to the sample and analysing the collected HPLC-fractions by mass spectrometry (MS) using a thermionic source. Since the matrix element was not collected, interference from this element during the mass spectrometric analysis was avoided. Detection limits as low as 0.5 mg/kg could then be obtained. Detection limits as low as 0.05 mg/kg were possible by MS without HPLC-pre-separation, but this approach could only be used for those elements that were not affected by the matrix. Commercial samples of high purity Nd 2 O 3 , Gd 2 O 3 and Dy 2 O 3 were analysed in this study, and a comparison of results obtained by HPLC, combined HPLC/MS and direct MS is presented. (Author)

Final Radiological Assessment of External Exposure for CLEAR-Line Americium Recovery Operations

Energy Technology Data Exchange (ETDEWEB)

Davis, Adam C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Belooussova, Olga N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hetrick, Lucas Duane [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-11-12

Los Alamos National Laboratory is currently planning to implement an americium recovery program. The americium, ordinarily isotopically pure 241Am, would be extracted from existing Pu materials, converted to an oxide and shipped to support fabrication of americium oxide-beryllium neutron sources. These operations would occur in the currently proposed Chloride Extraction and Actinide Recovery (CLEAR) line of glove boxes. This glove box line would be collocated with the currently-operational Experimental Chloride Extraction Line (EXCEL). The focus of this document is to provide an in-depth assessment of the currently planned radiation protection measures and to determine whether or not further design work is required to satisfy design-goal and ALARA requirements. Further, this document presents a history of americium recovery operations in the Department of Energy and high-level descriptions of the CLEAR line operations to provide a basis of comparison. Under the working assumptions adopted by this study, it was found that the evaluated design appears to mitigate doses to a level that satisfies the ALARA-in-design requirements of 10 CFR 835 as implemented by the Los Alamos National Laboratory procedure P121. The analyses indicate that extremity doses would also meet design requirements. Dose-rate calculations were performed using the radiation transport code MCNP5 and doses were estimated using a time-motion study developed in consort with the subject matter expert. A copy of this report and all supporting documentation are located on the Radiological Engineering server at Y:\\Rad Engineering\\2013 PROJECTS\\TA-55 Clear Line.

Recovery and separation of rare-earth elements, barium, and strontium from bastnasite with sulfuric acid

International Nuclear Information System (INIS)

Eisele, J.A.; Bauer, D.J.

1974-01-01

A bench-scale investigation was made of a concentrated H 2 SO 4 reaction for recovering and separating rare earth elements, barium, and strontium from a bastnaesite ore and byproduct. Barium and strontium were dissolved in the concentrated acid and precipitated as a mixed product by water dilution. Separation of strontium from barium was effected by reaction with Na 2 CO 3 solution, followed by a dilute acid leach of the SrCO 3 formed. After removing the barium and strontium from bastnaesite ore, the rare-earth elements were roasted to water-soluble sulfates. The rare earth sulfate solution was subsequently processed by solvent extraction to produce rare-earth oxides low in lead and magnesium. (U.S.)

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.

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

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)

Recovery of plutonium and americium from chloride salt wastes by solvent extraction

International Nuclear Information System (INIS)

Reichley-Yinger, L.; Vandegrift, G.F.

1987-01-01

Plutonium and americium can be recovered from aqueous waste solutions containing a mixture of HCl and chloride salt wastes by the coupling of two solvent extraction systems: tributyl phosphate (TBP) in tetrachloroethylene (TCE) and octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) in TCE. In the flowsheet developed, the salt wastes are dissolved in HCl, the Pu(III) is oxidized to the IV state with NaClO 2 and recovered in the TBP-TCE cycle, and the Am is then removed from the resultant raffinate by the CMPO-TCE cycle. The consequences of the feed solution composition and extraction behavior of these species on the process flowsheet design, the Pu-product purity, and the decontamination of the aqueous raffinate from transuranic elements are discussed. 16 refs., 6 figs

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

Science.gov (United States)

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

2001-08-15

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

DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

Energy Technology Data Exchange (ETDEWEB)

NA

2004-11-22

The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) important to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are in the form of tabulated functions with pH and log (line integral) CO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. The output data from this report are fundamental inputs for Total System Performance Assessment for the License Application (TSPA-LA) to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for all of the actinides. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

Molecular localisation of americium, technetium and cesium in edible marine animals. Their metabolic behavior and their consequences

International Nuclear Information System (INIS)

Pieri, J.; Goudard, F.; Milcent, M.C.

1992-01-01

We show the molecular behavior of americium, technetium and cesium on the chromatographic pattern of each cytosol in the digestive gland of eel and lobster. The contamination by cadmium seems to compete with americium in the fractions of MW 10,000. Cesium shows an ionic behavior. (author)

Application of extraction chromatography to the recovery of neptunium, plutonium and americium from an industrial waste

International Nuclear Information System (INIS)

Madic, C.; Kertesz, C.; Sontag, R.; Koehly, G.

1980-01-01

A pilot scale investigation was made to evaluate the possible application of the extraction chromatographic method (LLC) to the partitioning of alpha emitters from liquid wastes containing traces of transuranium elements. A secondary purpose was to obtain pure Am0 2 , which is used to produce alpha, gamma, and neutron sources. The process developed for alpha partitioning consists essentially of the extraction of macro amounts of uranium with 30% TBP in dodecane in mixer-settlers, then coextraction of Np-237, Pu-239, and Am-241 by LLC on a macro column filled with di-n-hexyl-octoxy-methyl-phosphine oxide (POX.11) adsorbed on an inert support. In each run about 200 liters of initial waste are decontaminated of alpha emitters. The loading step is followed by selective elution of americium, neptunium, and plutonium. The americium eluate is then subjected to the following operations: (1) separation of Am from Fe and Cd by LLC on a TBP column and (2) separation of Am from lanthanide traces by LLC on an HD(DiBM)P column after oxidation of Am(III) to Am(VI). The Am in the eluate is subsequently reduced to Am(III) and precipitated as oxalate with oxalic acid. The oxalate is then filtered and calcined to yield pure AmO 2

Determination of rare-earth elements in rocks by isotope-excited X-ray fluorescence spectrometry

DEFF Research Database (Denmark)

Kunzendorf, Helmar; Wollenberg, H.A.

1970-01-01

Isotope-excited X-ray fluorescence spectrometry furnishes a rapid determination of rare-earth elements in unprepared rock samples. The samples are excited by 241Am γ-rays, generating X-ray spectra on a multichannel pulse-height analyser. Gaussian peaks of the Kα and Kβ X-ray energies are treated ......-ray spectrometric scan of a longitudinally sliced drill core showed a close correlation between rare-earth abundances and appropriate minerals.......Isotope-excited X-ray fluorescence spectrometry furnishes a rapid determination of rare-earth elements in unprepared rock samples. The samples are excited by 241Am γ-rays, generating X-ray spectra on a multichannel pulse-height analyser. Gaussian peaks of the Kα and Kβ X-ray energies are treated...

PIXE studies on elemental characterization of offset printing ink tagged with rare-earth taggants

International Nuclear Information System (INIS)

Joseph, D.; Saxena, A.; Choudhury, R.K.; Maind, S.D.

2007-01-01

Proton Induced X-ray Emission Technique (PIXE) has been used for elemental characterization of offset printing ink tagged with rare-earth taggants, with a proton beam of energy 4 MeV at Folded Tandem Ion Accelerator (FOTIA) at BARC, Trombay, Mumbai, India. The offset printing ink was tagged with rare-earth (La, Pr, Nd, Sm, Eu and Gd) thenoyltrifluoroacetonate chelates at about 1000 ppm level for each element separately. Small aliquots (approximately 20 mg) of tagged inks were coated on paper supports and then analyzed. Well-resolved rare-earth L X-rays were detected using a high resolution Si(Li) detector. Satisfactory results to identify and quantify the taggants were achieved. (author)

Americium/curium bushing melter drain tests

International Nuclear Information System (INIS)

Smith, M.E.; Hardy, B.J.; Smith, M.E.

1997-01-01

Americium and curium were produced in the past at the Savannah River Site (SRS) for research, medical, and radiological applications. They have been stored in a nitric acid solution in an SRS reprocessing facility for a number of years. Vitrification of the americium/curium (Am/Cm) solution will allow the material to be safely stored or transported to the DOE Oak Ridge Reservation. Oak Ridge is responsible for marketing radionuclides for research and medical applications. The bushing melter technology being used in the Am/Cm vitrification research work is also under consideration for the stabilization of other actinides such as neptunium and plutonium. A series of melter drain tests were conducted at the Savannah River Technology Center to determine the relationship between the drain tube assembly operating variables and the resulting pour initiation times, glass flowrates, drain tube temperatures, and stop pour times. Performance criteria such as ability to start and stop pours in a controlled manner were also evaluated. The tests were also intended to provide support of oil modeling of drain tube performance predictions and thermal modeling of the drain tube and drain tube heater assembly. These drain tests were instrumental in the design of subsequent melter drain tube and drain tube heaters for the Am/Cm bushing melter, and therefore in the success of the Am/Cm vitrification and plutonium immobilization programs

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.

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)

Determination of plutoniumn and transplutonium elements in the environment

International Nuclear Information System (INIS)

Willemot, J.M.; Verry, M.; Jeanmaire, L.

1988-01-01

Environmental samples made of many different stable elements and natural emitting radionuclides must undergo chemical analysis allowing to prepare quality sources. Plutonium and americium sources with a good resolution can be obtained from environmental samples by successive operations of co-precipitation ion-exchange separation and solvent extraction. Spectral analysis is then simple and consequently plutonium and transplutonium elements are determined easily in such samples. 15 refs [fr

The Marine Geochemistry of the Rare Earth Elements

Science.gov (United States)

1983-09-01

C3): 2045-2056. BACON, M.P., P.G. BREWER, D.W. SPENCER, T.W. MURRAY & T. GODDARD (1980). Lead - 210 , polonium - 210 , manganese and iron in the Cariaco...191 La and Pr 197 Ce: its oxidation and reduction 197 Eu 207 4.5. Conclusions 210 CHAPTER 5. Behaviour of the Rare Earth Elements in anoxic waters of...seawater and algal food . When the radioactive particles were no longer available, the accumulated radioactivity of the zooplankters was rapidly lost

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.

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.

The rapid determination of americium curium, and uranium in urine by ultrafiltration

International Nuclear Information System (INIS)

Stradling, G.N.; Popplewell, D.S.; Ham, G.J.; Griffin, R.

1975-01-01

The rapid ultrafiltration method developed for the assay of plutonium has been extended to the determination of americium, curium and uranium in urine. The limits of detection for americium and curium, and uranium are 0.09 and 0.12 dm -1 l -1 respectively, and the analysis time excluding counting less than 2 hours. The method can therefor be effectively used as a rapid screening procedure. When the reference level for plutonium is exceeded, the α activity may require to be characterised. The single ultrafiltration technique must be modified for turbid urine samples. The method is inappropriate, except for uranium, when the urine contains DTPA. (author)

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.)

Geochemical characteristics of trace and rare earth elements in Xiangyangping uranium deposit of Guangxi

International Nuclear Information System (INIS)

Chen Qi; Xiao Jianjun; Fan Liting; Wen Cheng

2013-01-01

The trace and rare earth elements analysis were performed on two kinds ore-hosting rocks (Xiangcaoping granite and Douzhashan granite), alternated cataclastic granite and uranium ores in Xiangyangping uranium deposit of Guangxi. The results show that both of the two kinds granites display similar maturity features of highly evolved crust with the enrichment of Rb, Th, U, Ta and Pb, the depletion of Ba and Sr, high Rb/Sr and low Nb/Ta ratio, moderately rich light rare earth elements, strong negative Eu anomaly. Moreover, Douzhashan granite have higher Rb/Sr ratio and U content, which indicate it experienced more sufficient magma evolution and have higher potential of uranium source. There are almost no change in the content of trace and rare earth elements and distribution patterns during chloritization, hydromicazation and potash feldspathization of granite, but there occurred uranium enrichment and mineralization and REE remobilization while hematitization was superposed. This suggest that hematitization is most closely correlated with uranium mineralization in the working area. Because Most hematitization cataclastic rocks and uranium ore display similar geochemical characteristics to Douzhashan granite with relative high Rb/Sr and low Nb/Ta, Zr/Hf, ΣREE, LREE/HREE ration, and the trace and rare earth elements content and distribution patterns of some Xiangcaoping hematitization cataclastic rocks are between the two kinds of granite, therefore it can be concluded that the mineralization materials were mainly from Douzhashan granite and partly from Xiangcaoping granite. (authors)

Unraveling Recrystallization Mechanisms Governing Texture Development from Rare Earth Element Additions to Magnesium

Science.gov (United States)

Imandoust, Aidin

The origin of texture components associated with rare-earth (RE) element additions in wrought magnesium (Mg) alloys is a long-standing problem in magnesium technology. The objective of this research is to identify the mechanisms accountable for rare-earth texture during dynamic recrystallization (DRX). Towards this end, we designed binary Mg-Cerium and Mg-Gadolinium alloys along with complex alloy compositions containing zinc, yttrium and Mischmetal. Binary alloys along with pure Mg were designed to individually investigate their effects on texture evolutions, while complex compositions are designed to develop randomized texture, and be used in automotive and aerospace applications. We selected indirect extrusion to thermo-mechanically process our materials. Different extrusion ratios and speeds were designed to produce partially and fully recrystallized microstructures, allowing us to analyze DRX from its early stages to completion. X-ray diffraction, electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) were used to conduct microstructure and texture analyses. Our analyses revealed that rare-earth elements in zinc-containing magnesium alloys promote discontinuous dynamic recrystallization at the grain boundaries. During nucleation, the effect of rare earth elements on orientation selection was explained by the concomitant actions of multiple Taylor axes in the same grain. Isotropic grain growth was observed due to rare earth elements segregating to grain boundaries, which lead to texture randomization. The nucleation in binary Mg-RE alloys took place by continuous formation of necklace structures. Stochastic relaxation of basal and non-basal dislocations into low-angle grain boundaries produced chains of embryos with nearly random orientations. Schmid factor analysis showed a lower net activation of dislocations in RE textured grains compared to ones on the other side of the stereographic triangle. Lower dislocation densities within

Effect of rare earth elements on uranium electrodeposition in LiCl-KCI eutectic salt

International Nuclear Information System (INIS)

Park, Sung Bin; Kang, Young Ho; Hwang, Sung Chan; Lee, Han Soo; Peak, Seung Woo; Ahn, Do Hee

2015-01-01

It is necessary to investigate the electrodeposition behavior of uranium and other elements on the cathode in the electrorefining process to recover the uranium selectively from the reduced metals of the electrolytic reduction process since transuranic elements and rare earth elements is dissolved in the LiCl-KCl eutectic salt. Study on separation factors of U, Ce, Y and Nd based on U and Ce was performed to investigate the deposition behavior of the cathode with respect to the concentration of rare earth elements in LiCl-KCl eutectic salt. After electrorefining with constant current mode by using Ce metal as a sacrifice anode, the contents of U, Ce, Y and Nd in the salt phase and the deposit phase of the cathode were analyzed, and separation factors of the elements were obtained from the analyses. Securing conditions of pure uranium recovery in the electrorefining process was investigated by considering the separation factors with respect to UCl 3 and CeCl 3 /UCl 3 ratio

Determination Of Rare Earth And Other Elements In YEN-PHU Rare Earth Ore And Other Intermediate Products From The Floatation And Hydrometallurgical Process On Portable XRF Si-PIN Detector

International Nuclear Information System (INIS)

Doan Thanh Son; Phung Vu Phong; Nguyen Hanh Phuc

2014-01-01

The concentration of rare earths elements such as La, Ce, Pr, Nd, Gd and other elements as Ca, Fe, U, Th in Yen Phu rare earth ore and other intermediate products from the flotation and hydrometallurgical process was determined by using Si-PIN detector fluorescence spectrometry. The precision and accuracy of quantitative analysis was tested by standard reference materials and comparative analysis with different analytical methods. The analytical procedures were set-up and applied for the determination of rare earth and other elements in Yen Phu rare earth ore and other intermediate products from the flotation and hydrometallurgical process with high precision and accuracy. (author)

The weak acid resin process: a dustless conversion route for the synthesis of americium bearing-blanket precursors

International Nuclear Information System (INIS)

Picart, S.; Gauthe, A.; Parant, P.; Remy, E.; Jobelin, I.; Pomared, J.M.; Grangaud, P.; Dauby, J.; Delahaye, T.; Caisso, M.; Bataille, M.; Bayle, J.P.; Frost, C.; Delage, C.; Martin, C.L.; Ayral, E.

2016-01-01

Mixed uranium-americium oxides are one of the materials envisaged for Americium Bearing Blankets dedicated to transmutation in fast neutron reactors. Conversion and fabrication processes are currently developed to make those materials in the form of dense and homogeneous oxide ceramic pellets or dense granulates incorporating uranium and americium. Their development points out the need of a simplified and optimized process which could lower hazards linked to dust generation of highly contaminating and irradiating compounds and facilitate material transfer in remote handling operations. This reason motivated the development of innovative 'dustless' route such as the Weak Acid Resin route (WAR) which provides the oxide precursors in the form of sub-millimeter-sized microspheres with optimal flowability and limits dust generation during conversion and fabrication steps. This study is thus devoted to the synthesis of mixed uranium-americium oxide microspheres by the WAR process and to the characterization of such precursors. This work also deals with their application to the fabrication of dense or porous pellets and with their potential use as dense spherules to make Sphere-Pac fuel. (authors)

The weak acid resin process: a dustless conversion route for the synthesis of americium bearing-blanket precursors

Energy Technology Data Exchange (ETDEWEB)

Picart, S.; Gauthe, A.; Parant, P.; Remy, E.; Jobelin, I.; Pomared, J.M.; Grangaud, P.; Dauby, J.; Delahaye, T. [CEA, Centre de Marcoule, DEN/MAR/DRCP, F-30207 Bagnols-sur-Ceze (France); Caisso, M.; Bataille, M.; Bayle, J.P. [CEA, Centre de Marcoule, DEN/MAR/DTEC, F-30207 Bagnols-sur-Ceze (France); Frost, C. [CEA, Centre de Marcoule, DEN/MAR/DRCP, F-30207 Bagnols-sur-Ceze (France); Institut Europeen des Membranes, CNRS-ENSCM-UM, CC47, University of Montpellier, F-34095 Montpellier (France); Delage, C. [CEA, Centre de Cadarache, DEN/CAD/DEC, Saint-Paul-lez-Durance (France); Martin, C.L. [Univ. Grenoble Alpes, CNRS, SIMAP, F-38000 Grenoble (France); Ayral, E. [Institut Europeen des Membranes, CNRS-ENSCM-UM, CC47, University of Montpellier, F-34095 Montpellier (France)

2016-07-01

Mixed uranium-americium oxides are one of the materials envisaged for Americium Bearing Blankets dedicated to transmutation in fast neutron reactors. Conversion and fabrication processes are currently developed to make those materials in the form of dense and homogeneous oxide ceramic pellets or dense granulates incorporating uranium and americium. Their development points out the need of a simplified and optimized process which could lower hazards linked to dust generation of highly contaminating and irradiating compounds and facilitate material transfer in remote handling operations. This reason motivated the development of innovative 'dustless' route such as the Weak Acid Resin route (WAR) which provides the oxide precursors in the form of sub-millimeter-sized microspheres with optimal flowability and limits dust generation during conversion and fabrication steps. This study is thus devoted to the synthesis of mixed uranium-americium oxide microspheres by the WAR process and to the characterization of such precursors. This work also deals with their application to the fabrication of dense or porous pellets and with their potential use as dense spherules to make Sphere-Pac fuel. (authors)

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.

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

Change of sulfide inclusions in steel microalloying with rare earth and alkaline-earth elements

International Nuclear Information System (INIS)

Averin, V.V.; Polonskaya, S.M.; Chistyakov, V.F.

1977-01-01

The conditions for the formation of sulfides in molten and solid iron were determined by considering the thermodynamics of the interaction of sulfur and of oxygen with various components. It was shown in casting of low-carbon steel under a blanket of slag-forming briquettes, calcium of the silicocalcium partly passes to iron and to the sulfide phase. The sulfide inclusions with calcium in rolling become lens-shaped and acquire a greater strength, proportional to the content of calcium, thus ensuring a lesser anisotropy of steel. The change in the shape and the composition of sulfide inclusions effects the fracture of the metal which changes in type from separation along lamellar inclusions to a plastic fracture, i.e., enhances resilience. It is thus noted that rare-earth and alkali-earth elements, in particular, cerium and calcium are promising agents for desulfurating molten iron

Rare earth element concentrations and Nd isotopes in the Southeast Pacific Ocean

Science.gov (United States)

Jeandel, C.; Delattre, H.; Grenier, M.; Pradoux, C.; Lacan, F.

2013-02-01

vertical profiles of rare earth element concentrations and Nd isotopic compositions have been measured in the remote southeast Pacific Ocean. The three stations represent contrasting environments: the oligotrophic center of the gyre (station GYR), the "transition zone" east of the South Tropical Front (station EGY), and the Peru-Chile upwelling marked by a pronounced oxygen minimum (station UPX). Rare earth concentrations display nutrient like vertical profiles except at UPX where surface waters are enriched. At this station Nd isotopic compositions are clearly more radiogenic than in the open ocean, suggesting that boundary exchange process is releasing lithogenic rare earth element from the volcanic Andes. Unexpected radiogenic values (ɛNd reaching -3.7) are also observed at 2000 m at station GYR in the Upper Circumpolar Deep Water that commonly have ɛNd values around -6. Exchange processes related to hydrothermal activity are suspected to produce this increase in ɛNd in the vicinity of the East Pacific Rise. These results provide some guidance for higher resolution studies planned in this region by the international GEOTRACES program.

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

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.

Origin assessment of uranium ore concentrates based on their rare-earth elemental impurity pattern

Energy Technology Data Exchange (ETDEWEB)

Varga, Z.; Wallenius, M.; Mayer, K. [Commission of the European Communities, Karlsruhe (Germany). European Inst. for Transuranium Elements

2010-07-01

The rare-earth element pattern was used as an additional tool for the identification and origin assessment of uranium ore concentrates (yellow cakes) for nuclear forensic purposes. By this means, the source of an unknown material can be straightforwardly verified by comparing the pattern with that of a known or declared sample. In contrast to other indicators used for nuclear forensic studies, the provenance of the material can also be assessed in several cases even if no comparison sample is available due to the characteristic pattern. The milling process was found not to change the pattern and no significant elemental fractionation occurs between the rare-earth elements, thus the pattern in the yellow cakes corresponds to that found in the uranium ore. (orig.)

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 %

Assessing rare earth elements in quartz rich geological samples

International Nuclear Information System (INIS)

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

2016-01-01

Sodium peroxide (Na_2O_2) 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 "1"5"7Gd 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 Na_2O_2/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. - Highlights: • Na_2O_2 fusion coupled to ICP-MS/MS was used to determine REE in quartz-rich samples. • The method accuracy was checked with a geological reference material and INAA. • Results were within 80–98% recovery of QLO-1 reference material, comparable to INAA. • Detection limits were generally below 10 pg g"−"1, and repeatability was below 15%. • Na_2O_2/ICP-MS/MS proved to be a suitable method for REE in quartz-rich samples.

Production of a tracer packet of heavier rare earth elements

International Nuclear Information System (INIS)

Lahiri, S.; Nayak, D.; Maji, S.

2004-01-01

Production of a tracer packet of heavier rare earth elements containing carrier-free radionuclides of 153,155 Tb, 153,155,157 Dy, 159 Ho, 159,161 Er, 161 Tm produced by medium energy 7 Li and 12 C irradiation on an europium oxide target and the subsequent separation of bulk europium from the carrier-free products is described. (author)

Synthesis and physicochemical investigation of complexes of rare earth, alkaline earth elements and copper with some β-diketones

International Nuclear Information System (INIS)

Nichiporuk, R.V.; Pechurova, N.I.; Snezhko, N.I.; Martynenko, L.I.; Kaul', A.R.; Zanina, A.S.; Shergina, S.I.; Sokolov, I.E.

1991-01-01

Complexes of rare earth, alkaline earth elements and copper with 2-methoxy-2,6,6-trimethylheptanedion-3,5 as well as complexes of yttrium and barium with 2-methoxy-2,6-dimethylheptanedion-3,5 were synthesized. Prepared complexes were investigated by the methods of chemical, thermal, X-ray phase analyses, IR spectroscopy. Complex sublimation was studied at 10 -1 -10 -2 mm Hg. Complexes of rare earths and copper don't change their composition during sublimation, and sublimation of hydrated complexes of barium, strontium and calcium leads to formation of anhydrous complexes. All prepared complexes are able to transsublimate multiply and qualitatively without change of composition. All isolated complexes can be used for preparation of film oxide coatings by CVD method

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.

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.

Higher Americium Oxidation State Research Roadmap

Energy Technology Data Exchange (ETDEWEB)

Mincher, Bruce J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Law, Jack D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Goff, George S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moyer, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burns, Jon D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lumetta, Gregg J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sinkov, Sergey I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shehee, Thomas C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hobbs, David T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-12-18

The partitioning of hexavalent Am from dissolved nuclear fuel requires the ability to efficiently oxidize Am(III) to Am(VI) and to maintain that oxidation state for a length of time sufficient to perform the separation. Several oxidants have been, or are being developed. Chemical oxidants include Ag-catalyzed ozone, Ag-catalyzed peroxydisulfate, Cu(III) periodate, and sodium bismuthate. Hexavalent americium has also now successfully been prepared by electrolysis, using functionalized electrodes. So-called auto-reduction rates of Am(VI) are sufficiently slow to allow for separations. However, for separations based on solvent extraction or ion exchange using organic resins, the high valence state must be maintained under the reducing conditions of the organic phase contact, and a holding oxidant is probably necessary. Until now, only Cu(III) periodate and sodium bismuthate oxidation have been successfully combined with solvent extraction separations. Bismuthate oxidation provided the higher DAm, since it acts as its own holding oxidant, and a successful hot test using centrifugal contactors was performed. For the other oxidants, Ag-catalyzed peroxydisulfate will not oxidize americium in nitric acid concentrations above 0.3 M, and it is not being further investigated. Peroxydisulfate in the absence of Ag catalysis is being used to prepare Am(V) in ion exchange work, discussed below. Preliminary work with Ag-catalyzed ozone has been unsuccessful for extractions of Am(VI) from 6.5 M HNO3, and only one attempt at extraction, also from 6.5 M HNO3, using the electrolytic oxidation has been attempted. However, this high acid concentration was based on the highest Am extraction efficiency using the bismuthate oxidant; which is only sparingly soluble, and thus the oxidation yield is based on bismuthate solubility. Lower acid concentrations may be sufficient with alternative oxidants and work with Ag-ozone, Cu(III) and electrolysis is on-going. Two non

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

Investigations for chromatographic separation and determination of the rare earths and auxiliary group elements

International Nuclear Information System (INIS)

Post, K.

1981-01-01

Different method have been developed to quantitatively determine rare earth elements after their column chromatographic separation. The influence of the active solvents in the running systems diethyl ether/tetra hydrofuran (THF)/nitric acid (HNO 3 ) and diethyl ether/bis-(2-ethyl hexyl) phosphate (HDEHP)/HNO 3 was investigated on the column chromatographic separation of all rare earth elements is possible by the synergistic combination of the active running components THF and HDEHP. Further from product isotopes could also be separated using the running agents described here in investigations to separate fission product mixtures of irradiated uranium. (orig./HBR) [de

Transplutonium elements production program: extraction chromatographic process for plutonium irradiated targets

International Nuclear Information System (INIS)

Bourges, J.; Madic, C.; Koehly, G.

1980-01-01

The treatment of irradiated plutonium targets by extraction chromatography allowed the purification of the isotopes 243 Am and 244 Cm on the scale of few tens of grams. This process proved to be extremely simple and flexible, and yielded results which are reproducible in time. The chief advantage of the TBP process over the HDEHP process in high and medium activity conditions lies in the rapid absorption/desorption kinetics of the elements to be purified and in the separation of americium from curium, which largely offsets its lower selectivity for lanthanide elements. it is certainly possible to improve the performance of this process by: a) optimization of the characteristics of the stationary phase, b) improvement in the filling technique and in hydraulic operation of the columns, c) on-line analysis of americium (the key element in actinide/lanthanide separation) in the eluate. The application of extraction chromatography with HD(DiBM)P to the purification of 243 Am of the end of treatment makes the process more consistent, eliminates the delicate stages implemented in hot cell, and considerably improves final product quality

Determination of rare earth elements by photometric microtitration using xylenol orange

International Nuclear Information System (INIS)

Kuban, V.; Jancarova, I.; Sommer, L.

1989-01-01

Stock solutions were prepared of rare earth elements in approx 0.1M nitric acid, xylenol orange and EDTA. All measurements were made using a double-beam digital recording spectrophotometer (Superscan 3) with a titration measuring cell with a volume of approx. 30 ml and optical length of 20 mm. Titration agents were pipetted using an automatic piston microburette. Measured were absorbance pH curves of solutions of several lanthanides with xylenol orange, the absorption spectra of solutions of xylenol orange with lanthanides with increasing addition of titration agents EDTA, and the titration curves of the dependence of absorbance of lanthanide solutions with xylenol orange during titration with the EDTA solution. It was found that photometric microtitration allowed accurate and correct determination of all rare earth elements within the concentration range 0.04 - 0.5 mmol/l by titration with standard EDTA solution of a concentration of xylenol orange of 20 μmol/l. (E.S.). 4 figs., 3 tabs., 7 refs

Activation analysis of rare-earth elements in opium and cannabis samples. [Neutron reactions

Energy Technology Data Exchange (ETDEWEB)

Henke, G [Muenster Univ. (Germany, F.R.). Inst. fuer Pharmazeutische Chemie

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/sup 13/n cm/sup -2/sec/sup -1/. Cooling period 2-3 days. After addition of 0.1 ..mu..Ci /sup 139/Ce and rare-earth carriers wet ashing of irradiated samples with H/sub 2/SO/sub 4//HNO/sub 3/, followed by alternate addition of HNO/sub 3/ and H/sub 2/O/sub 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.

Contemporary state of plutonium and americium in the soils of Palesse state radiation-ecological reserve

International Nuclear Information System (INIS)

Papenia, M.V.; Sokolik, G.A.; Ovsiannikova, S.V.; Voinikava, E.V.; Svirschevsky, S.F.; Brown, J.; Skipperud, L.

2010-01-01

Full text: At present, the most important alpha-emitting radionuclides of Chernobyl origin are Pu 238, Pu 239, Pu 240 and Am 241. They are classified as the most dangerous group of radionuclides in view of the long half-lives and high radiotoxicity. The main part of alpha-emitted radionuclides is located within the Palesse State Radiation-Ecological Reserve. One of the most important factors determining the radioecological situation in the contaminated ecosystems is the physicochemical forms of radionuclides in a soil medium. Radionuclide species determine the radionuclide entrance into the soil solutions, their redistribution in soil profiles and the 'soil - plant' and the 'soil - surface, ground or underground water' systems as well as spreading beyond the contaminated area. The present work is devoted to investigation of state and migration ability of plutonium and americium in soils of the Palesse state radiation-ecological reserve after more than 20 years from the Chernobyl accident. The objects of investigation were mineral and organic soils sampled in 2008 with the step of 5 cm to the depth of 25-30 cm. The forms of plutonium and americium distinguishing by association with the different components of soil and by potential for migration in the soil medium were studied using the method of sequential selective extraction according to the modified Tessier scheme. Activities of Pu 238, Pu 239, Pu 240 and Am 241 in the samples were determined by the method of radiochemical analysis with alpha-spectrometer radionuclide identification. The dominant part of plutonium and americium in the soils is in immobile forms. Nowadays, radionuclide portions in water soluble and reversibly bound forms do not exceed 9.4 % of radionuclide content in the soil. In mineral soil samples, the radionuclide portions in these fractions exceed the corresponding portions in organic ones. In both mineral and organic soils, the portions of mobile americium are higher than plutonium. The

Osteosarcoma induction by plutonium-239, americium-241 and neptunium-237 : the problem of deriving risk estimates for man

International Nuclear Information System (INIS)

Taylor, D.M.

1988-01-01

Spontaneous bone cancer (osteosarcoma) represents only about 0.3% of all human cancers, but is well known to be inducible in humans by internal contamination with radium-226 and radium-224. plutonium-239, americium-241 and neptunium-237 form, or will form, the principal long-lived alpha particle emitting components of high activity waste and burnt-up nuclear fuel elements. These three nuclides deposit extensively in human bone and although, fortunately, no case of a human osteosarcoma induced by any of these nuclides is known, evidence from animal studies suggests that all three are more effective than radium-226 in inducing osteosarcoma. The assumption that the ratio of the risk factors, the number of osteosarcoma expected per 10000 person/animal Gy, for radium-226 and any other bone-seeking alpha-emitter will be independent of animal species has formed the basis of all the important studies of the radiotoxicity of actinide nuclides in experimental animals. The aim of this communication is to review the risk factors which may be calculated from the various animal studies carried out over the last thirty years with plutonium-237, americium-241 and neptunium-237 and to consider the problems which may arise in extrapolating these risk factors to homo sapiens

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

Solvent extraction of rare earth elements by γ-ray spectrometry

International Nuclear Information System (INIS)

Sudha Vani, T.J.; Krishna Rao, K.S.V.; Krishna Reddy, L.; Jaya Rami Reddy, M.; Lee, Yong III

2010-01-01

Rare earth element (REE) is a mine of new material and has very wide uses in industry. India has second largest abundant resources of rare earths and with its products and exports playing an important part in the world. REEs are important in nuclear energy programs, hence the separation and purification of rare earths is demanded. As well known, the separation between trivalent REEs is one of the most difficult tasks in separation chemistry due to their similar chemical properties. A large number of acidic and neutral organo-phosphorus and sulphur extractants have been widely employed industrially for the solvent extraction separation of REEs. However, these reagents display various shortcomings, such as poor selectivity, third phase formation, etc. In view of the ever increasing demand for high purity REEs as a group or from one another, there is a growing interest in the development of new and more selective solvent extraction reagents

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

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.

Contribution to the study of higher valency states of americium

International Nuclear Information System (INIS)

Langlet, Jean.

1976-01-01

Study of the chemistry of the higher valencies of americium in aqueous solutions and especially the autoreduction phenomenon. First a purification method of americium solutions is studied by precipitation, solvent extraction and ion exchange chromatography. Studies of higher valency states chemical properties are disturbed by the autoreduction phenomenon changing Am VI and Am V in Am III more stable. Stabilization of higher valency states, characterized by a steady concentration of Am VI in solution, can be done by complexation of Am VI and Am V ions or by a protecting effect of foreign ions. The original medium used has a complexing effect by SO 4 2- ions and a protecting effect by the system S 2 O 8 2- -Ag + consuming H 2 O 2 main reducing agent produced by water radiolysis. These effects are shown by the study of Am VI in acid and basic solutions. A mechanism of the stabilization effect is given [fr

Lifetime followup of the 1976 americium accident victim: [Final report

International Nuclear Information System (INIS)

Breitenstein, B.D. Jr.; Palmer, H.E.

1988-05-01

This report describes the 11 year medical course of Harold R. McCluskey, a Hanford nuclear chemical operator, who, at age 64, was involved in an accident in an americium recovery facility in August 1976. As a result of the accident, he was heavily contaminated with americium (Am-241), sustained a substantial internal deposition of this isotope, and was burned with concentrated nitric acid and injured by flying debris about the face and neck. The immediate and long-term medical care is summarized, including decontamination procedures, chelation therapy, and routine and special clinical laboratories studies. The estimates of the operator's Am-241 deposition, post accident and during the remainder of his life and the special techniques and equipment used to make the estimates, are reported. Post-accident, the total amount of Am-241 excreted in his urine and feces was 41 MBq (1.1 mCi). He died of complications of chronic coronary artery disease on August 17, 1987. 20 refs., 2 figs

A new potentiometric method for the estimation of the rare earth elements

International Nuclear Information System (INIS)

Selig, W.S.

1988-01-01

Chinese workers recently described a new potentiometric method for lead using sodium tetraphenylborate (NaTPB) as a titrant. Based on a previous Chinese publication, the authors have recently developed a method for the estimation of the alkaline earth metals by sequential titration with NaTPB. In the present work, the authors report a similar method for the estimation of the rare earth elements, including Sc and Y. The sensing electrode is a spectrographic graphite rod, coated with a solution of poly(vinyl chloride) and dioctylphthalate in tetrahydrofuran as previously described. The reference electrode was a double-junction Ag/AgCl electrode. The titration system is controlled by a Tektronix 4051 graphics computer system. Single cations or mixtures up to 0.5 mequiv are determined by potentiometric titration with 0.05 N NaTPB, after formation of the oxonium cations by reaction with an aqueous solution of poly(ethylene glycol) (PEG). Best results are obtained with PEGs of molecular weights from 8,000 to 20,000. Sequential estimation of Pb + Ba, Sr, and Ca, and the sum of the rare earth elements is also reported, plus possible applications to Al, Ga, and anions precipitated by lead

The determination of minor amounts of rare earth elements in high purity earth oxides by HPLC/IDMS

International Nuclear Information System (INIS)

Stijfhoorn, D.E.; Stray, H.; Hjelmseth, H.

1991-05-01

Since the early seventies isotopic dilution mass spectrometry (IDMS) has been used at Institutt for energiteknikk, Kjeller, Norway for determination and certification of rare earth elements in high purity Y 2 O 3 . These lanthanides have, during the last few decades, become more widely used in highly specialized technology. High purity, quality 4 N (99.99%) or even 5 N materials are needed for phosphors, lasers, optical fibers, X-ray films, and in contrast fluids for magnetic resonance imaging (MRI). However, in a matrix constisting primarily of a single lanthanide, IDMS alone will not be effective due to isobaric interferences from the main elements or the mono-oxides formed in the ion source. On the other hand, high performance liquid chromatography (HPLC) may be used, but the detection limit will be in the order of 5 to 10 ppm/W. In this work a combination of HPLC and IDMS has been used to lower the detection limit to 1 ppm/W, where the sample is spiked before separation by HPLC, followed by IDMS analysis of the HPLC- fractions. In some cases the HPLC-process has to be repeated to remove the main element completly. Results are presented for Dy 2 O 3 and Nd 2 O 3 , but similar separating procedures can be applied for other rare earth oxides. 3 refs., 2 figs. 2 tabs

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

Ingestion Pathway Transfer Factors for Plutonium and Americium

International Nuclear Information System (INIS)

Blanchard, A.

1999-01-01

Overall transfer factors for major ingestion pathways are derived for plutonium and americium. These transfer factors relate the radionuclide concentration in a given foodstuff to deposition on the soil. Equations describing basic relationships consistent with Regulatory Guide 1.109 are followed. Updated values and coefficients from IAEA Technical Reports Series No. 364 are used when a available. Preference is given to using factors specific to the Savannah River Site

Behavior of americium, curium, and certain fission products in fluoride melts in the presence of s olid extraction agents

International Nuclear Information System (INIS)

Alekseev, V.A.; Klokman, V.R.; Morozova, Z.E.; Ziv, V.S.

1986-01-01

The authors consider the behavior of americium, curium, and certain fission products (europium, cerium, yttrium, and strontium) in fluoride and chlode-fluoride melts in the presence of nonisomorphous solid phases: calcium fluoride and lanthanum and zirconium oxides. It is shown that the trace components enter the solid calcium fluoride in a regular fashion only in the presence of an adequate amount of oxygen in the melt. The effect of oxygen on the coprecipitation with calcium fluoride occurs because oxygen compounds of the elements must be formed in the melt, and these are then coprecipitated with the calcium fluoride

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

Transfer across the human gut of environmental plutonium, americium, cobalt, caesium and technetium: studies with cockles (Cerastoderma edule) from the Irish Sea

International Nuclear Information System (INIS)

Hunt, G.J.

1998-01-01

Our previous studies have indicated lower values of the gut transfer factor ('f L values') for plutonium and americium in winkles (Littorina littorea) than adopted by ICRP. The present study was undertaken primarily to investigate whether this observation extends to other species. Samples of cockles (Cerastoderma edule) from Ravenglass, Cumbria were eaten by volunteers who provided 24 samples of urine and faeces. Urine samples indicated f L values for cockles which were higher than for winkles; for plutonium these ranged overall up to 7x10 -4 with an arithmetic mean in the range (2-3)x10 -4 , and for americium up to 2.6x10 -4 with an arithmetic mean of 1.2x10 -4 . Limited data based on volunteers eating cockles from the Solway suggest that f L values for americium may be greater at distance from Sellafield. The measured values compare with 5x10 -4 used by the ICRP for environmental forms of both elements, which would appear to provide adequate protection when calculating doses from Cumbrian cockles. Data for other nuclides were obtained by analysing faecal samples from the volunteers who ate the Ravenglass cockles. Cobalt-60 showed an f L value in the region of 0.2, twice the value currently used by ICRP. For 137 Cs, variabilities were indicated in the range 0.08 to 0.43, within the ICRP value of f L =1.0. Technetium-99 gave f L values up to about 0.6, in reasonable conformity with the ICRP value of 0.5. (author)

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.

Preparation of new phthalocyanine complexes of some rare-earth elements

International Nuclear Information System (INIS)

Sugimoto, Hiroshi; Higashi, Teruaki; Mori, Masayasu

1982-01-01

The reaction of tris(1,3-diphenyl-1,3-propanedionato) complexes of heavier rare-earth elements, M 3+ (dbm) 3 and lithium phthalocyaninato (2-), Li 2 (pc) gave two types of new stable phthalocyanine complexes, [M 3+ (pc)(dbm)(dbmH)] and [M 3+ (pc)(dbm)] depending on the solvents used for the preparation. The structure of both types of complexes are tentatively proposed. (author)

Cleanex process: a versatile solvent extraction process for recovery and purification of lanthanides, americium, and curium

International Nuclear Information System (INIS)

Bigelow, J.E.; Collins, E.D.; King, L.J.

1979-01-01

At a concentration of 1 M in straight-chain hydrocarbon diluent, HDEHP will extract americium, curium, and other trivalent actinide and lanthanide elements from dilute acid or salt solutions. The solute is back-extracted with more concentrated acid, either nitric or hydrochloric. The process has been used in the continuous, countercurrent mode, but its greatest advantage arises in batch extractions where the excess acid can be titrated with NaOH to produce a final acidity of about 0.03 M. Under these conditions, 99% recovery can be achieved, usually in one stage. Cleanex was used on the 50-liter scale at the Transuranium Processing Plant at Oak Ridge for 12 years to provide a broad spectrum cleanup to transuranium elements before applying more sophisticated techniques for separating individual products. The process is also used routinely to recover excessive losses of curium and/or californium from plant waste streams. The solvent system is relatively resistant to radiation damage, being usable up to 200 W-h/liter

Density of simulated americium/curium melter feed solution

International Nuclear Information System (INIS)

Rudisill, T.S.

1997-01-01

Vitrification will be used to stabilize an americium/curium (Am/Cm) solution presently stored in F-Canyon for eventual transport to Oak Ridge National Laboratory and use in heavy isotope production programs. Prior to vitrification, a series of in-tank oxalate precipitation and nitric/oxalic acid washes will be used to separate these elements and lanthanide fission products from the bulk of the uranium and metal impurities present in the solution. Following nitric acid dissolution and oxalate destruction, the solution will be denitrated and evaporated to a dissolved solids concentration of approximately 100 g/l (on an oxide basis). During the Am/Cm vitrification, an airlift will be used to supply the concentrated feed solution to a constant head tank which drains through a filter and an in-line orifice to the melter. Since the delivery system is sensitive to the physical properties of the feed, a simulated solution was prepared and used to measure the density as a function of temperature between 20 to 70 degrees C. The measured density decreased linearly at a rate of 0.0007 g/cm3/degree C from an average value of 1.2326 g/cm 3 at 20 degrees C to an average value of 1.1973g/cm 3 at 70 degrees C

Density of simulated americium/curium melter feed solution

Energy Technology Data Exchange (ETDEWEB)

Rudisill, T.S.

1997-09-22

Vitrification will be used to stabilize an americium/curium (Am/Cm) solution presently stored in F-Canyon for eventual transport to Oak Ridge National Laboratory and use in heavy isotope production programs. Prior to vitrification, a series of in-tank oxalate precipitation and nitric/oxalic acid washes will be used to separate these elements and lanthanide fission products from the bulk of the uranium and metal impurities present in the solution. Following nitric acid dissolution and oxalate destruction, the solution will be denitrated and evaporated to a dissolved solids concentration of approximately 100 g/l (on an oxide basis). During the Am/Cm vitrification, an airlift will be used to supply the concentrated feed solution to a constant head tank which drains through a filter and an in-line orifice to the melter. Since the delivery system is sensitive to the physical properties of the feed, a simulated solution was prepared and used to measure the density as a function of temperature between 20 to 70{degrees} C. The measured density decreased linearly at a rate of 0.0007 g/cm3/{degree} C from an average value of 1.2326 g/cm{sup 3} at 20{degrees} C to an average value of 1.1973g/cm{sup 3} at 70{degrees} C.

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.

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.

Choice of excitation source for determination of rare earth elements with radioisotope excited X ray fluorescence

International Nuclear Information System (INIS)

Zhang Quanshi; Chang Yongfu

2000-01-01

The comparisons of two radioisotope source ( 241 Am and 238 Pu) which are the most available in the radioisotope excited X Ray Fluorescence (XRF) analysis technique and two characteristic X ray series (KX and LX) analyzed for the determination of the rare-earth (RE) elements were investigated in detail. According to the principle of emission and detection of X ray , the relative excitation efficiencies were calculated by the some fundamental physical parameters including the photoelectric mass attenuation coefficient, the fluorescent yield, the absorption jump factor, the emission probability of the detected fluorescent line with reference to other liens of the same series etc., The advantages and disadvantages of the two conditions are discussed. These results may determine the optimal excitation and detection conditions for different rare-earth elements. The experimental results with nine rare-earth elements (Ce, Nd, Sm, Tb, Tm, Ho, Er, Yb and Lu) are in agreement with the results of theoretical calculations

Transmutation of americium and curium incorporated in zirconia-based host materials

International Nuclear Information System (INIS)

Raison, P.E.

2001-01-01

Presented are studies involving the incorporation of americium and curium in zirconia-based materials. First explored was the pseudo ternary system AmO 2 -ZrO 2 -Y 2 O 3 . It was determined that selected Y-CSZ materials can incorporate significant quantities of americium oxide and remain cubic single-phase. The cell parameters of these fluorite-type products were established to be linear with the AmO 2 content. The Cm 2 O 3 -ZrO 2 system was also investigated. It was found that at 25 mol% of CmO 1.5 , the Cm(III) stabilized zirconia in its cubic form (a = 5.21 ±0.01 Angstrom). At higher and lower concentrations, diphasic materials were encountered. At 50 mol% of CmO 1.5 , a pyrochlore oxide - Cm 2 Zr 2 O 7 - is formed (a = 10.63 ±0.02 Angstrom). (author)

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.

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

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)

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

Energy Technology Data Exchange (ETDEWEB)

Salles, Paula M.B. de; Campos, Tarcisio P. R. de, E-mail: pauladesalles@yahoo.com.br [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Menezes, Maria Angela de B.C., E-mail: menezes@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2015-07-01

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{sub 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)

Separation and measurement of thorium, plutonium, americium, uranium and strontium in environmental matrices

International Nuclear Information System (INIS)

Harrison, Jennifer J.; Zawadzki, Atun; Chisari, Robert; Wong, Henri K.Y.

2011-01-01

A technique for the isolation of thorium (Th), plutonium (Pu), americium (Am), uranium (U) and strontium (Sr) isotopes from various environmental matrices has been adapted from a previously published method specific to water samples (). Separation and isolation of the various elemental fractions from a single sub-sample is possible, thereby eliminating the need for multiple analyses. The technique involves sample dissolution, concentration via calcium phosphate co-precipitation, rapid column extraction using TEVA TM , TRU TM and Sr-Spec TM resin cartridges, alpha spectrometry for Th, Pu, U and Am and Cerenkov counting for Sr. Various standard reference materials were analysed and chemical yields are in the range of 70-80% for Th, Am, U and Sr and 50-60% for Pu. Sample sizes of up to 10 L for water, 5 g for dry soil and sediment and 10 g for dry vegetation and seaweed can be processed using this technique.

Rare earth element behaviour and hydrothermal alteration, Lihir Island, Papua New Guinea

International Nuclear Information System (INIS)

Lottermoser, B.G.

1990-01-01

This contribution documents extreme rare earth elements (REE) mobility associated with a currently active subaerial hydrothermal system on Lihir Island, Papua New Guinea, which is host to a large epithermal gold deposit. Instrumental thermal activation analysis for selected REE and for other trace elements has been performed at the Lucas Heights Research Laboratories in Sydney. Samples and standards were irradiated with thermal neutrons and subsequently counted on coaxial and planar detectors after several decay periods. The gamma-ray spectra were processed using FORTRAN data reduction program. The wide range of (La/Lu) c n, (La/Sm) c n and (Tb/Lu) c n ratios reflects a pronounced mobilisation and fractionation of REE during the hydrothermal process. It is estimated that the increasing fractionation of REE, and especially of 'light rare earth' (La to Sm), up the alteration sequence is the result of decreasing pH, temperature and alkalinity of the hydrothermal fluids with increasing alteration intensity. 15 refs., 2 figs

Biokinetics of a transuranic (238PU) and a rare earth element (152Eu) in the lobster (Homarus gammarus): transfer mechanisms (accumulation and detoxification) in organs and at the cellular level

International Nuclear Information System (INIS)

Tocquet, N.

1995-01-01

The work presented here is an experimental investigation of the biokinetics of transfer of a transuranic and a rare earth element ( 238 Pu and 152 Eu) in the lobster Homarus gammarus. The study of 238 Pu biokinetics forms part of a wider framework of research concerning the transfer of transuranic elements in marine species, while the study of 152 Eu is carried out with a view to supporting the analogy between the behaviour of transuranics and rare earths in living organisms. Exactly the same experimental protocol, based on techniques from various disciplines (biology, biochemistry and metrology), was used to Investigate the biokinetics of transfer of these two radionuclides. The Individual lobsters were radiolabelled by means of one-shot or chronic ingestion of spiked meals. As the first approach, the kinetics and transfer mechanisms were studied In whole animal samples and in different organs distinct series of pathways through the different organs were identified in the case of both radionuclides, being mainly linked to digestive processes induced by the meal as well as the transport function of hemo-lymph in this way, the Important role of the digestive gland was picked out, with two of four cellular types displaying a successive involvement In the fixation and then the retention of the studied radionuclides. As a corroborative approach, the digestive gland was subjected to a more detailed investigation with the aim of describing the mechanisms of Incorporation and elucidating transfer processes at the cellular and molecular levels. 238 Pu is preferentially partitioned into the cytosol, where it is associated with various constituents such as ferritin (iron-storing protein). 152 Eu is more diffusely distributed in the hepato-pancreatic cells, while the lysosomes appear to play a more important role during transfer. The results obtained in this study, both on the macroscopic scale (i.e. the whole animal and different organs) as well as the cellular and molecular

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

International Nuclear Information System (INIS)

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

2014-01-01

Highlights: • The article provides a new method for recycling rare earth (RE) from waste phosphor. • When compared with the traditional methods, leach rate was much higher. • Y–Eu concentrate and Tb–Ce concentrate were obtained successively. • It would reduce the burden of later extraction, separation and purification. - Abstract: 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 (Y 0.95 Eu 0.05 ) 2 O 3 in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce 0.67 Tb 0.33 MgAl 11 O 19 ) and the Blue phosphor (Ba 0.9 Eu 0.1 MgAl 10 O 17 ) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO 2 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

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

International Nuclear Information System (INIS)

Sneden, Christopher; Lawler, James E.; Den Hartog, Elizabeth A.; Cowan, John J.; Ivans, Inese I.

2009-01-01

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

Application of delayed X-ray spectrometry to the analysis of some rare earth elements

International Nuclear Information System (INIS)

Pillay, A.E.; Mboweni, R.C.M.

1991-01-01

The capabilities of delayed x-ray spectrometry preceded by isotope-source thermal neutron activation for the specific determination of some rare earth elements (Sm, Eu, Dy, Ho) in small powdered samples was evaluated. The feasibility study relied heavily on the low-energy sensitivity of the detector used. Detection of the delayed x-rays was achieved with a 100-mm 2 Ge detector with the ability to produce optimum photopeak-to-noise ratios. The rare earth elements were chosen on the basis of their inherent favourable nuclear properties for producing a practicable x-ray yield and on the demand for their analysis. Analytical results are presented over a range of concentrations for the elements of interest and the potential of the technique for application to their general routine analysis is discussed. Interferences from the sample matrix can be suppressed to an extent that makes the method almost independent of the matrix. This and other features make the technique a strong rival to conventional activation analysis. (author)

A volatile topic: Parsing out the details of Earth's formation through experimental metal-silicate partitioning of volatile and moderately volatile elements

Science.gov (United States)

Mahan, B. M.; Siebert, J.; Blanchard, I.; Badro, J.; Sossi, P.; Moynier, F.

2017-12-01

Volatile and moderately volatile elements display different volatilities and siderophilities, as well as varying sensitivity to thermodynamic controls (X, P, T, fO2) during metal-silicate differentiation. The experimental determination of the metal-silicate partitioning of these elements permits us to evaluate processes controlling the distribution of these elements in Earth. In this work, we have combined metal-silicate partitioning data and results for S, Sn, Zn and Cu, and input these characterizations into Earth formation models. Model parameters such as source material, timing of volatile delivery, fO2 path, and degree of impactor equilibration were varied to encompass an array of possible formation scenarios. These models were then assessed to discern plausible sets of conditions that can produce current observed element-to-element ratios (e.g. S/Zn) in the Earth's present-day mantle, while also satisfying current estimates on the S content of the core, at no more than 2 wt%. The results of our models indicate two modes of accretion that can maintain chondritic element-to-element ratios for the bulk Earth and can arrive at present-day mantle abundances of these elements. The first mode requires the late addition of Earth's entire inventory of these elements (assuming a CI-chondritic composition) and late-stage accretion that is marked by partial equilibration of large impactors. The second, possibly more intuitive mode, requires that Earth accreted - at least initially - from volatile poor material preferentially depleted in S relative to Sn, Zn, and Cu. From a chemical standpoint, this source material is most similar to type I chondrule rich (and S poor) materials (Hewins and Herzberg, 1996; Mahan et al., 2017; Amsellem et al., 2017), such as the metal-bearing carbonaceous chondrites.

Determination of rare-earth elements in rocks by isotope-excited X-ray fluorescence spectrometry

DEFF Research Database (Denmark)

Kunzendorf, Helmar; Wollenberg, H.A.

1970-01-01

Isotope-excited X-ray fluorescence spectrometry furnishes a rapid determination of rare-earth elements in unprepared rock samples. The samples are excited by 241Am γ-rays, generating X-ray spectra on a multichannel pulse-height analyser. Gaussian peaks of the Kα and Kβ X-ray energies are treated......-ray spectrometric scan of a longitudinally sliced drill core showed a close correlation between rare-earth abundances and appropriate minerals....

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

Science.gov (United States)

Rodrigues, Luiz Eduardo Oliveira Carmo; Mansur, Marcelo Borges

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

Transmutation of americium and curium incorporated in zirconia-based host materials

Energy Technology Data Exchange (ETDEWEB)

Raison, P.E. [CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. d' Etudes des Combustibles; Haire, R.G. [Oak Ridge National Lab., TN (United States)

2001-07-01

Presented are studies involving the incorporation of americium and curium in zirconia-based materials. First explored was the pseudo ternary system AmO{sub 2}-ZrO{sub 2}-Y{sub 2}O{sub 3}. It was determined that selected Y-CSZ materials can incorporate significant quantities of americium oxide and remain cubic single-phase. The cell parameters of these fluorite-type products were established to be linear with the AmO{sub 2} content. The Cm{sub 2}O{sub 3}-ZrO{sub 2} system was also investigated. It was found that at 25 mol% of CmO{sub 1.5}, the Cm(III) stabilized zirconia in its cubic form (a = 5.21 {+-}0.01 Angstrom). At higher and lower concentrations, diphasic materials were encountered. At 50 mol% of CmO{sub 1.5}, a pyrochlore oxide - Cm{sub 2}Zr{sub 2}O{sub 7} - is formed (a = 10.63 {+-}0.02 Angstrom). (author)

Rare earths

Energy Technology Data Exchange (ETDEWEB)

Cranstone, D A

1979-01-01

Rare earth elements are commonly extracted from the minerals monazite, bastnaesite, and xenotine. New uses for these elements are constantly developing; they have found applications in glass polishing, television tube phosphors, high-strength low-alloy steels, magnets, catalysts, refractory ceramics, and hydrogen sponge alloys. In Canada, rare earths have been produced as byproducts of the uranium mining industry, but there was no production of rare earths in 1978 or 1979. The world sources of and markets for the rare earth elements are discussed.

Experimental studies to validate model calculations and maximum solubility limits for Plutonium and Americium

International Nuclear Information System (INIS)

2017-01-01

This report focuses on studies of KIT-INE to derive a significantly improved description of the chemical behaviour of Americium and Plutonium in saline NaCl, MgCl 2 and CaCl 2 brine systems. The studies are based on new experimental data and aim at deriving reliable Am and Pu solubility limits for the investigated systems as well as deriving comprehensive thermodynamic model descriptions. Both aspects are of high relevance in the context of potential source term estimations for Americium and Plutonium in aqueous brine systems and related scenarios. Americium and Plutonium are long-lived alpha emitting radionuclides which due to their high radiotoxicity need to be accounted for in a reliable and traceable way. The hydrolysis of trivalent actinides and the effect of highly alkaline pH conditions on the solubility of trivalent actinides in calcium chloride rich brine solutions were investigated and a thermodynamic model derived. The solubility of Plutonium in saline brine systems was studied under reducing and non-reducing conditions and is described within a new thermodynamic model. The influence of dissolved carbonate on Americium and Plutonium solubility in MgCl 2 solutions was investigated and quantitative information on Am and Pu solubility limits in these systems derived. Thermodynamic constants and model parameter derived in this work are implemented in the Thermodynamic Reference Database THEREDA owned by BfS. According to the quality assurance approach in THEREDA, is was necessary to publish parts of this work in peer-reviewed scientific journals. The publications are focused on solubility experiments, spectroscopy of aquatic and solid species and thermodynamic data. (Neck et al., Pure Appl. Chem., Vol. 81, (2009), pp. 1555-1568., Altmaier et al., Radiochimica Acta, 97, (2009), pp. 187-192., Altmaier et al., Actinide Research Quarterly, No 2., (2011), pp. 29-32.).

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)

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

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.

Determination of aluminium, scandium and rare earth elements by emission flame spectrometry

International Nuclear Information System (INIS)

Otruba, V.; Sommer, L.

1989-01-01

Emission spectrometry in nitrous oxide-acetylene flames in combination with a highly resolving double monochromator and sensitive detecting system enables simple, sensitive and selective determinations of aluminium, scandium and all rare earth elements with exception of cerium in complicated matrices. Calibration plots are linear for a large concentration interval (≤ 100 μgxml -1 ), detection limits are in ngxml -1 level and RSD does not exceed 3% on the optimal concentration level of the particular element. The determination of Al, Sc, Eu and Yb showed particular advantages as to methods using ICP-spectrometry. (orig.)

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...

Electrodeposition of americium on a liquid cadmium cathode from a molten salt bath

International Nuclear Information System (INIS)

Laplace, A.; Lacquement, J.; Maillard, C.; Donner, L.

2004-01-01

A high-activity experiment involving the electrode position of americium on a liquid cadmium cathode from a LiCl-KCl eutectic with about 3 g of AmO 2 was conducted in a shielded cell in the ATALANTE complex. After describing the electrolyzer and the experimental conditions, the authors discuss the preparation of the LiCl-KCl-AmCl 3 solution and briefly review its electrochemical properties. It was clearly confirmed that Am(III) reduction on an inert solid cathode occurs in two steps forming Am(II) before Am(0), whereas only one reduction step was observed on liquid cadmium. The main results of this study concern americium electrode position on the liquid cadmium cathode (recovery yields, current densities, problems encountered). The solvent properties of cadmium for actinide/lanthanide separation are discussed. (authors)

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

Energy Technology Data Exchange (ETDEWEB)

Liu, Hu [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Shengen, E-mail: zhangshengen@mater.ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Pan, Dean; Tian, Jianjun; Yang, Min; Wu, Maolin [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Volinsky, Alex A. [Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620 (United States)

2014-05-01

Highlights: • The article provides a new method for recycling rare earth (RE) from waste phosphor. • When compared with the traditional methods, leach rate was much higher. • Y–Eu concentrate and Tb–Ce concentrate were obtained successively. • It would reduce the burden of later extraction, separation and purification. - Abstract: 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 (Y{sub 0.95}Eu{sub 0.05}){sub 2}O{sub 3} in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce{sub 0.67}Tb{sub 0.33}MgAl{sub 11}O{sub 19}) and the Blue phosphor (Ba{sub 0.9}Eu{sub 0.1}MgAl{sub 10}O{sub 17}) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO{sub 2} 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.

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.

Effects of rare earth elements La and Yb on the morphological and functional development of zebrafish embryos

Institute of Scientific and Technical Information of China (English)

Jun'an Cui; Zhiyong Zhang; Wei Bai; Ligang Zhang; Xiao He; Yuhui Ma; Yan Liu; Zhifang Chai

2012-01-01

In recent years,with the wide applications and mineral exploitation of rare earth elements,their potential environmental and health effects have caused increasing public concern.Effect of rare earth elements La and Yb on the morphological and functional development of zebrafish embryos were studied.The embryos were exposed to La3+ or Yb3+ at 0,0.01,0.1,0.3,0.5 and 1.0 mmol/L,respectively.Early life stage parameters such as egg and embryo mortality,gastrula development,tail detachment,eyes,somite formation,circulatory system,pigmentation,malformations,hatching rate,length of larvae and mortality were investigated.The results showed La3+ and Yb3+ delayed zebrafish embryo and larval development,decreased survival and hatching rates,and caused tail malformation in a concentration-dependent way.Moreover,heavy rare-earth ytterbium led to more severe acute toxicity of zebrafish embryo than light rare-earth lanthanum.

Plutonium and americium extraction studies with bifunctional organophosphorus extractants

International Nuclear Information System (INIS)

Navratil, J.D.

1985-01-01

Neutral bifunctional organophosphorus extractants, such as octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and dihexyl-N,N-diethylcarbamoylmethylphosphonate (CMP), are under study at the Rocky Flats Plant (RFP) to remove plutonium and americium from the 7M nitric acid waste. These compounds extract trivalent actinides from strong nitric acid, a property which distinguishes them from monofunctional organiphosphorus reagents. Furthermore, the reagents extract hydroytic plutonium (IV) polymer which is present in the acid waste stream. The compounds extract trivalent actinides with a 3:1 stoichiometry, whereas tetra- and hexavalent actinides extract with a stoichiometry of 2:1. Preliminary studies indicate that the extracted plutonium polymer complex contains one to two molecules of CMP per plutonium ion and the plutonium(IV) maintains a polymeric structure. Recent studies by Horwitz and co-workers conclude that the CMPO and CMP reagents behave as monodentate ligands. At RFP, three techniques are being tested for using CMP and CMPO to remove plutonium and americium from nitric acid waste streams. The different techniques are liquid-liquid extraction, extraction chromatography, and solid-supported liquid membranes. Recent tests of the last two techniques will be briefly described. In all the experiments, CMP was an 84% pure material from Bray Oil Co. and CMPO was 98% pure from M and T Chemicals

Determination of plutonium, americium and curium in the marine environment

International Nuclear Information System (INIS)

Grenaut, CLaude; Germain, Pierre; Miramand, Pierre.

1982-01-01

The method used in the Laboratory for plutonium, americium and curium determination in marine samples (water, sediments, animals, plants) is presented. It is a modification of a procedure based on adsorption on ion exchange resins developed by other authors. The preliminary preparation of the samples, the radiochemical procedures and electrodeposition are described so as to be used as a practical handbook [fr

Separation and measurement of thorium, plutonium, americium, uranium and strontium in environmental matrices

Energy Technology Data Exchange (ETDEWEB)

Harrison, Jennifer J., E-mail: jennifer.harrison@ansto.gov.au [Australian Nuclear Science and Technology Organisation, PMB 1, Menai NSW 2234 (Australia); Zawadzki, Atun; Chisari, Robert; Wong, Henri K.Y. [Australian Nuclear Science and Technology Organisation, PMB 1, Menai NSW 2234 (Australia)

2011-10-15

A technique for the isolation of thorium (Th), plutonium (Pu), americium (Am), uranium (U) and strontium (Sr) isotopes from various environmental matrices has been adapted from a previously published method specific to water samples (). Separation and isolation of the various elemental fractions from a single sub-sample is possible, thereby eliminating the need for multiple analyses. The technique involves sample dissolution, concentration via calcium phosphate co-precipitation, rapid column extraction using TEVA{sup TM}, TRU{sup TM} and Sr-Spec{sup TM} resin cartridges, alpha spectrometry for Th, Pu, U and Am and Cerenkov counting for Sr. Various standard reference materials were analysed and chemical yields are in the range of 70-80% for Th, Am, U and Sr and 50-60% for Pu. Sample sizes of up to 10 L for water, 5 g for dry soil and sediment and 10 g for dry vegetation and seaweed can be processed using this technique.

[Rare earth elements content in farmland soils and crops of the surrounding copper mining and smelting plant in Jiangxi province and evaluation of its ecological risk].

Science.gov (United States)

Jin, Shu-Lan; Huang, Yi-Zong; Wang, Fei; Xu, Feng; Wang, Xiao-Ling; Gao, Zhu; Hu, Ying; Qiao Min; Li, Jin; Xiang, Meng

2015-03-01

Rare earth elements content in farmland soils and crops of the surrounding copper mining and smelting plant in Jiangxi province was studied. The results showed that copper mining and smelting could increase the content of rare earth elements in soils and crops. Rare earth elements content in farmland soils of the surrounding Yinshan Lead Zinc Copper Mine and Guixi Smelting Plant varied from 112.42 to 397.02 mg x kg(-1) and 48.81 to 250.06 mg x kg(-1), and the average content was 254.84 mg x kg(-1) and 144.21 mg x kg(-1), respectively. The average contents of rare earth elements in soils in these two areas were 1.21 times and 0.68 times of the background value in Jiangxi province, 1.36 times and 0.77 times of the domestic background value, 3.59 times and 2.03 times of the control samples, respectively. Rare earth elements content in 10 crops of the surrounding Guixi Smelting Plant varied from 0.35 to 2.87 mg x kg(-1). The contents of rare earth elements in the leaves of crops were higher than those in stem and root. The contents of rare earth elements in Tomato, lettuce leaves and radish leaves were respectively 2.87 mg x kg(-1), 1.58 mg x kg(-1) and 0.80 mg x kg(-1), which were well above the hygienic standard limit of rare earth elements in vegetables and fruits (0.70 mg x kg(-1)). According to the health risk assessment method recommended by America Environmental Protection Bureau (USEPA), we found that the residents' lifelong average daily intake of rare earth elements was 17.72 mg x (kg x d)(-1), lower than the critical value of rare earth elements damage to human health. The results suggested that people must pay attention to the impact of rare earth elements on the surrounding environment when they mine and smelt copper ore in Jiangxi.

Rare earth element patterns in nigerian coals

International Nuclear Information System (INIS)

Ewa, I.O.B.; Elegba, S.B.

1996-01-01

Rare Earth Elements (REE's) retain group coherence in their environment and are therefore useful geochemical markers. We report the pattern of ten REE's (La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Yb, Lu) determined by Instrumental Neutron Activation Analysis (INAA) for coals obtained from eight mines in Nigeria, namely, Okaba, Enugu, Ogbete, Onyeama, Gombe, Lafia, Asaba and Afikpo. Our results show the existence of fractionations with the highest index of 13.19 for Lafia coal, depletion in HREE, negative Eu anomaly for most of the coals, REE patterns that are consistent with chondritic trends; prominent (Eu/Eu * ) cn for Okaba and Gombe coals. Variations in geochemical data observed could suggest strong departures from band metamorphism during the coalification events of the Benue Trough geosynclines, where the coal deposits are all located. (author) 14 refs., 2 figs., 3 tabs

Plutonium and americium concentrations and vertical profiles in some Italian mosses used as bioindicators

International Nuclear Information System (INIS)

Testa, C.; Desideri, D.; Meli, M.A.; Guerra, F.; Degetto, S.; Jia, G.; Gerdol, R.

1998-01-01

We have examined the uptake of actinide elements Am and Pu by different species of lichen and moss collected in two locations (Urbino, Central Italy; Alps region, North-east Italy). Plutonium and americium were separated and determined by extraction chromatography, electrodeposition and alpha-spectrometry. This paper summarizes our results with a special emphasis on the vertical profiles of these actinides in two different species of mosses. Several 1-2 cm depth sections were obtained and dated by 210 Pb method. A typical peak for 239,240 Pu and 241 Am was found in the very old moss species ('Sphagnum Compactum') at a depth corresponding to the period 1960-1970 which was the period characterized by the maximum nuclear weapon tests. In a younger moss species ('Neckeria Crispa') no peak was observed and the regression curves showed that Am is more mobile than 239,240 Pu and 238 Pu. (author)

1976 Hanford americium-exposure incident: decontamination and treatment facility

International Nuclear Information System (INIS)

Berry, J.R.; McMurray, B.J.; Jech, J.J.; Breitenstein, B.D.; Quigley, E.J.

1982-01-01

An injured worker, contaminated with over 6 mCi of americium-241, required special treatment and housing for 4 months. This paper is a description of the design and management of the facility in which most of the treatment and housing occurred. The problems associated with contamination control, waste handling, supplies, and radiological concerns during the two-stage transfer of the patient from a controlled situation to his normal living environment are discussed in detail

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%)

Marine geochemistry of the rare earth elements: a review

International Nuclear Information System (INIS)

Kennedy, H.; Elderfield, H.

1984-01-01

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

The transmutation of americium: the Ecrix experiments in Phenix; Transmutation de l'americium: les experiences ecrix dans Phenix

Energy Technology Data Exchange (ETDEWEB)

Garnier, J C; Schmidt, N [CEA Cadarache, Dept. d' Etudes des Combustibles (DEC/SESC), 13 - Saint-Paul-lez-Durance (France); Croixmarie, Y; Ottaviani, J P [CEA Cadarache, Dept. d' Etudes des Combustibles (DEC/SPUA), 13 - Saint-Paul-lez-Durance (France); Varaine, F; Saint Jean, C de [CEA Cadarache, Dept. d' Etudes des Reacteurs (DER/SPRC), 13 - Saint-Paul-lez-Durance (France)

1999-07-01

The first americium transmutation experiment in a specific target in PHENIX will occur with the ECRIX-B and ECRIX-H experiments. Beside material testing, the objective is also to represent a concept of transmutation whose specificity is to enhance the kinetics of transmutation by using a moderated spectrum. The moderator materials will be {sup 11}B{sub 4}C and CaH{sub 2} for ECRIX-B and ECRIXH respectively, the irradiation conditions have been predicted for both the neutronics and thermal. The targets (MgO-AmO{sub X} pellets) are manufactured in the ATALANTE laboratory and the design is performed according to the PHENIX operating conditions. (authors)

Sustainability evaluation of essential critical raw materials: cobalt, niobium, tungsten and rare earth elements

Science.gov (United States)

Tkaczyk, A. H.; Bartl, A.; Amato, A.; Lapkovskis, V.; Petranikova, M.

2018-05-01

The criticality of raw materials has become an important issue in recent years. As the supply of certain raw materials is essential for technologically-advanced economies, the European Commission and other international counterparts have started several initiatives to secure reliable and unhindered access to raw materials. Such efforts include the EU Raw Materials Initiative, European Innovation Partnership on Raw Materials, US Critical Materials Institute, and others. In this paper, the authors present a multi-faceted and multi-national review of the essentials for the critical raw materials (CRMs) Co, Nb, W, and rare earth elements (REEs). The selected CRMs are of specific interest as they are considered relevant for emerging technologies and will thus continue to be of increasing major economic importance. This paper presents a ‘sustainability evaluation’ for each element, including essential data about markets, applications and recycling, and possibilities for substitution have been summarized and analysed. All the presented elements are vital for the advanced materials and processes upon which modern societies rely. These elements exhibit superior importance in ‘green’ applications and products subject to severe conditions. The annual production quantities are quite low compared to common industrial metals. Of the considered CRMs, only Co and REE gross production exceed 100 000 t. At the same time, the prices are quite high, with W and Nb being in the range of 60 USD kg‑1 and some rare earth compounds costing almost 4000 USD kg‑1. Despite valiant effort, in practice some of the considered elements are de facto irreplaceable for many specialized applications, at today’s technological level. Often, substitution causes a significant loss of quality and performance. Furthermore, possible candidates for substitution may be critical themselves or available in considerably low quantities. It can be concluded that one preferred approach for the

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.

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...

Recycling of Rare Earth Elements

Science.gov (United States)

Lorenz, Tom; Bertau, Martin

2017-01-01

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

Uptake and recovery of americium and uranium by Anacystis biomass

International Nuclear Information System (INIS)

Liu, H.H.; Jiunntzong Wu

1993-01-01

The optimum conditions for the uptake of americium and uranium from wastewater solutions by Anacystis nidulans cells, and the recovery of these radionuclides were studied. The optimum pH range for both actinides was in the acidic region between 3.0 and 5.0. In a pH 3.5 solution with an algal biomass of 70 μg/mL, up to 95% of the Am and U were taken up by the cells. However, the uptake levels were lowered considerably when ethylene dinitrilotetraacetic acid (EDTA) or iron or calcium ions were present in the solutions. Most of the radionuclides taken up by the cells could also be desorbed by washing with salt solutions. Of nine salt solutions tested, ammonium carbonate was the most effective. Our experiments using algal biomass to remove radionuclides from wastewater showed that about 92% of americium and 85% of uranium in wastewater could be taken up by algal biomass, from which about 46% of the Am and 82% of the U originally present in the wastewater could be recovered by elution with a salt solution. 17 refs., 7 figs., 2 tabs

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)

Rare earth elements determination in medicinal plants by Neutron Activation Analisys

Energy Technology Data Exchange (ETDEWEB)

Goncalves, Rodolfo D.M.R.; Francisconi, Lucilaine S.; Silva, Paulo S.C. da, E-mail: rdmrg89@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

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)

Rare earths as a future resource

International Nuclear Information System (INIS)

Cornell, D.H.

1988-01-01

The fourteen rare earth or lanthanide elements have recently emerged as an important natural resource because of the rapidly growing demand in the electronic, chemical and metallurgical industries. The Symposium on rare earth elements as a future resource presented a multidisciplinary review of rare earth chemistry, geology, beneficiation, industrial applications and marketing. Papers by experts in many fields were presented on the following topics: chemical properties of the rare earth elements; the analysis of rare earth elements and minerals; beneficiation and extraction of rare earth elements; economic geochemistry and mineralogy of rare earths; present industrial uses of rare earth elements; the role of rare earth elements in high-temperature superconductors; the technical application of high-temperature superconductors; supply and demand for rare earth products - now and in the future, and the geology of rare earth deposits

Picomolar traces of americium(III) introduce drastic changes in the structural chemistry of terbium(III). A break in the ''gadolinium break''

Energy Technology Data Exchange (ETDEWEB)

Welch, Jan M. [TU Wien, Atominstitut, Vienna (Austria); Mueller, Danny; Knoll, Christian; Wilkovitsch, Martin; Weinberger, Peter [TU Wien, Institute of Applied Synthetic Chemistry, Vienna (Austria); Giester, Gerald [University of Vienna, Institute of Mineralogy and Crystallography, Vienna (Austria); Ofner, Johannes; Lendl, Bernhard [TU Wien, Institute of Chemical Technologies and Analytics, Vienna (Austria); Steinhauser, Georg [Leibniz Universitaet Hannover, Institute of Radioecology and Radiation Protection (Germany)

2017-10-16

The crystallization of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] (ZT) in the presence of trace amounts (ca. 50 Bq, ca. 1.6 pmol) of americium results in 1) the accumulation of the americium tracer in the crystalline solid and 2) a material that adopts a different crystal structure to that formed in the absence of americium. Americium-doped [Tb(Am)(H{sub 2}O){sub 7}ZT]{sub 2} ZT.10 H{sub 2}O is isostructural to light lanthanide (Ce-Gd) 5,5{sup '}-azobis[1H-tetrazol-1-ide] compounds, rather than to the heavy lanthanide (Tb-Lu) 5,5{sup '}-azobis[1H-tetrazol-1-ide] (e.g., [Tb(H{sub 2}O){sub 8}]{sub 2}ZT{sub 3}.6 H{sub 2}O) derivatives. Traces of Am seem to force the Tb compound into a structure normally preferred by the lighter lanthanides, despite a 10{sup 8}-fold Tb excess. The americium-doped material was studied by single-crystal X-ray diffraction, vibrational spectroscopy, radiochemical neutron activation analysis, and scanning electron microscopy. In addition, the inclusion properties of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] towards americium were quantified, and a model for the crystallization process is proposed. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Determination of rare earth elements in seawater by inductively coupled plasma-mass spectrometry

International Nuclear Information System (INIS)

Moeller, P.; Dulski, P.; Luck, J.

1992-01-01

Shortly after sampling, rare earth elements (REEs) from 11.5 l of seawater were concentrated in 35 ml solutions by ion exchange chromatography on board the German research vessel ''Sonne'' using Chelex 100 chelating resin for preconcentration. Two millilitres of a 0.2 μg g -1 Lu spike was added to the seawater samples (i) for monitoring the chemical yield which was always found to vary between 85 and 112% (mean: 100±6) and (ii) as an internal standard. Rare earth elements have been determined by ICP-MS, with REE concentrations ranging from 100 (La) to 1 (Eu) pmol kg -1 . La in blanks can be as high as 30 pmol kg -1 , but blank concentrations for other REEs range between 0.5 and 0.01 pmol kg -1 . The trend of the precision of relative response factors varies between 12% (La) and 4% (Yb). The accuracy is estimated to be about 10% with the exception of La and Ce. Methodology improvements are suggested. (author)

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)

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.

A simple approach to determine the diffusivity of americium in granite

International Nuclear Information System (INIS)

Song, L.; Feng, X.; Liang, J.; Zhang, Y.; Wang, J.

2009-01-01

The diffusivities of the key radionuclides in host rock are important for the performance assessment of repositories. One of the conventional methods for determining the diffusivities of radionuclides is to grind the rock tablet layer by layer and then to measure the radioactivity remaining on the rock tablet before each grinding cycle. Since grinding hard rock samples, especially those with radioactivity, is very difficult, we developed a new approach to determine the diffusivity of americium in granite. The new approach mainly includes two parts: one is to measure the radioactivities from both sides of a rock disk sample by autoradiography with phosphor imaging technique; the other is to study the relationship between the radioactivities and the apparent diffusivity of americium in granite by computer modelling. Because the high contamination risk of grinding radioactive rock samples has been avoided, the new approach is much simpler than the conventional method. It may be a better choice of measuring the diffusivities of radionuclides in rock, especially for those laboratories in which grinding radioactive rock samples is inconvenient. (orig.)

Assessment of Bioavailable Concentrations of Germanium and Rare Earth Elements in the Rhizosphere of White Lupin (Lupinus albus L.)

Science.gov (United States)

Wiche, Oliver; Fischer, Ronny; Moschner, Christin; Székely, Balázs

2015-04-01

Concentrations of Germanium (Ge) and Rare Earth Elements in soils are estimated at 1.5 mg kg -1 (Ge), 25 mg kg -1 (La) and 20 mg kg -1 (Nd), which are only roughly smaller than concentrations of Pb and Zn. Germanium and rare earth elements are thus not rare but widely dispersed in soils and therefore up to date, only a few minable deposits are available. An environmental friendly and cost-effective way for Ge and rare earth element production could be phytomining. However, the most challenging part of a phytomining of these elements is to increase bioavailable concentrations of the elements in soils. Recent studies show, that mixed cultures with white lupine or other species with a high potential to mobilize trace metals in their rhizosphere due to an acidification of the soil and release of organic acids in the root zone could be a promising tool for phytomining. Complexation of Ge and rare earth elements by organic acids might play a key role in controlling bioavailability to plants as re-adsorption on soil particles and precipitation is prevented and thus, concentrations in the root zone of white lupine increase. This may also allow the complexes to diffuse along a concentration gradient to the roots of mixed culture growing species leading to enhanced plant uptake. However, to optimize mixed cultures it would be interesting to know to which extend mobilization of trace metals is dependent from chemical speciation of elements in soil due to the interspecific interaction of roots. A method for the identification of complexes of germanium and rare earth elements with organic acids, predominantly citric acid in the rhizosphere of white lupine was developed and successfully tested. The method is based on coupling of liquid chromatography with ICP-MS using a zic-philic column (SeQuant). As a preliminary result, we were able to show that complexes of germanium with citric acid exist in the rhizosphere of white lupin, what may contribute to the bioavailability of this

[Effects of rare earth elements on soil fauna community structure and their ecotoxicity to Holotrichia parallela].

Science.gov (United States)

Li, Guiting; Jiang, Junqi; Chen, Jie; Zou, Yunding; Zhang, Xincai

2006-01-01

By the method of OECD filter paper contact, this paper studied the effects of applied rare earth elements on soil fauna community structure and their ecological toxicity to Holotrichia parallela in bean field. The results showed that there were no significant differences between the treatments and the control in soil fauna species, quantity of main species, and diversity index. Urgent and chronic toxic test showed that the differences between the treatments and the control were not significant. It was suggested that within the range of test dosages, rare earth elements had little ecological toxicity to Holotrichia parallela, and did not change the soil fauna community structure.

Standard test method for quantitative determination of americium 241 in plutonium by Gamma-Ray spectrometry

CERN Document Server

American Society for Testing and Materials. Philadelphia

1994-01-01

1.1 This test method covers the quantitative determination of americium 241 by gamma-ray spectrometry in plutonium nitrate solution samples that do not contain significant amounts of radioactive fission products or other high specific activity gamma-ray emitters. 1.2 This test method can be used to determine the americium 241 in samples of plutonium metal, oxide and other solid forms, when the solid is appropriately sampled and dissolved. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Influence of dissolved organic substances in groundwater on sorption behavior of americium and neptunium

International Nuclear Information System (INIS)

Boggs, S. Jr.; Seitz, M.G.

1984-01-01

Groundwaters typically contain dissolved organic carbon consisting largely of high molecular weight compounds of humic and fulvic acids. To evaluate whether these dissolved organic substances can enhance the tranport of radionuclides through the groundwater system, experiments were conducted to examine the sorption of americium and neptunium onto crushed basalt in the presence of dissolved humic- and fulvic-acid organic carbon introduced into synthetic groundwater. The partitioning experiments with synthetic groundwater show that increasing the concentration of either humic or fulvic acid in the water has a significant inhibiting effect on sorption of both americium and neptunium. At 22 0 C, adsorption of these radionuclides, as measured by distribution ratios (the ratio of nuclide sorbed onto the solid to nuclide in solution at the end of the experiment), decreased by 25% to 50% by addition of as little as 1 mg/L dissolved organic carbon and by one to two orders of magnitude by addition of 100 to 200 mg/L dissolved organic carbon. Distribution ratios measured in solutions reacted at 90 0 C similarly decreased with the addition of dissolved organic carbon but generally ranged from one to two orders of magnitude higher than those determined in the 22 0 C experiment. These results suggest that organic carbon dissolved in deep groundwaters may significantly enhance the mobility of radionuclides of americium and neptunium. 23 references, 5 figures, 11 tables

Recovery of americium-241 from aged plutonium metal

International Nuclear Information System (INIS)

Gray, L.W.; Burney, G.A.; Reilly, T.A.; Wilson, T.W.; McKibben, J.M.

1980-01-01

After separation and purification, both actinides were precipitated as oxalates and calcined. A large-scale process was developed using dissolution, separation, purification, precipitation, and calcination. Efforts were made to control corrosion, to avoid product contamination, to keep the volume of process and waste solutions manageable, and to denitrate solutions with formic acid. The Multipurpose Processing Facility (MPPF), designed for recovery of transplutonium isotopes, was used for the first time for the precipitation and calcination of americium. Also, for the first time,, large-scale formic acid denitration was performed in a canyon vessel at SRP

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.

Upper limits to americium concentration in large sized sodium-cooled fast reactors loaded with metallic fuel

International Nuclear Information System (INIS)

Zhang, Youpeng; Wallenius, Janne

2014-01-01

Highlights: • The americium transmutation capability of Integral Fast Reactor was investigated. • The impact from americium introduction was parameterized by applying SERPENT Monte Carlo calculations. • Higher americium content in metallic fuel leads to a power penalty, preserving consistent safety margins. - Abstract: Transient analysis of a large sized sodium-cooled reactor loaded with metallic fuel modified by different fractions of americium have been performed. Unprotected loss-of-offsite power, unprotected loss-of-flow and unprotected transient-over-power accidents were simulated with the SAS4A/SASSYS code based on the geometrical model of an IFR with power rating of 2500 MW th , using safety parameters obtained with the SERPENT Monte Carlo code. The Ti-modified austenitic D9 steel, having higher creep rupture strength, was considered as the cladding and structural material apart from the ferritic/martensitic HT9 steel. For the reference case of U–12Pu–1Am–10Zr fuel at EOEC, the margin to fuel melt during a design basis condition UTOP is about 50 K for a maximum linear rating of 30 kW/m. In order to maintain a margin of 50 K to fuel failure, the linear power rating has to be reduced by ∼3% and 6% for 2 wt.% and 3 wt.% Am introduction into the fuel respectively. Hence, an Am concentration of 2–3 wt.% in the fuel would lead to a power penalty of 3–6%, permitting a consumption rate of 3.0–5.1 kg Am/TW h th . This consumption rate is significantly higher than the one previously obtained for oxide fuelled SFRs

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

Composition of the earth's upper mantle. II - Volatile trace elements in ultramafic xenoliths

Science.gov (United States)

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

1980-01-01

Radiochemical neutron activation analysis was used to determine the nine volatile elements Ag, Bi, Cd, In, Sb, Se, Te, Tl, and Zn in 19 ultramafic rocks, consisting mainly of spinel and garnet lherzolites. A sheared garnet lherzolite, PHN 1611, may approximate undepleted mantle material and tends to have a higher volatile element content than the depleted mantle material represented by spinel lherzolites. Comparisons of continental basalts with PHN 1611 and of oceanic ridge basalts with spinel lherzolites show similar basalt: source material partition factors for eight of the nine volatile elements, Sb being the exception. The strong depletion of Te and Se in the mantle, relative to lithophile elements of similar volatility, suggests that 97% of the earth's S, Se and Te may be in the outer core.

DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

Energy Technology Data Exchange (ETDEWEB)

P. Bernot

2005-07-13

The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this activity is to predict dissolved concentrations or solubility limits for elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) relevant to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are provided in the form of tabulated functions with pH and log fCO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. Even though selection of an appropriate set of radionuclides documented in Radionuclide Screening (BSC 2002 [DIRS 160059]) includes actinium, transport of Ac is not modeled in the total system performance assessment for the license application (TSPA-LA) model because of its extremely short half-life. Actinium dose is calculated in the TSPA-LA by assuming secular equilibrium with {sup 231}Pa (Section 6.10); therefore, Ac is not analyzed in this report. The output data from this report are fundamental inputs for TSPA-LA used to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for the actinides discussed in this report. These models cover broad ranges of environmental conditions so they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or

DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

International Nuclear Information System (INIS)

P. Bernot

2005-01-01

The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this activity is to predict dissolved concentrations or solubility limits for elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) relevant to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are provided in the form of tabulated functions with pH and log fCO 2 as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. Even though selection of an appropriate set of radionuclides documented in Radionuclide Screening (BSC 2002 [DIRS 160059]) includes actinium, transport of Ac is not modeled in the total system performance assessment for the license application (TSPA-LA) model because of its extremely short half-life. Actinium dose is calculated in the TSPA-LA by assuming secular equilibrium with 231 Pa (Section 6.10); therefore, Ac is not analyzed in this report. The output data from this report are fundamental inputs for TSPA-LA used to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for the actinides discussed in this report. These models cover broad ranges of environmental conditions so they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise

Determination of trace amounts of rare earth elements in various environmental samples by spark source mass spectrography

International Nuclear Information System (INIS)

Sugimae, Akiyoshi

1978-01-01

A chemical concentration-mass spectrographic procedure was described for the determination of trace amounts of rare earth elements in various environmental samples: airborne particulate matter, dustfall, soil and so forth. A 0.5 to 1 gram of sample material was decomposed by fusion with sodium carbonate. The silica dehydrated in the usual way was filtered off and the filtrate from the silica was then treated with ammonium hydroxide to precipitate the rare earth elements. After ignition of the precipitate, two ml of internal standard solution containing 20 μg/ml of silver were added and the mixture was then evaporated to dryness. The residue was mixed with an equal amount of graphite powder and then pressed into electrodes. Relative sensitivity coefficients (Ag=1.0) were determined by using Spex Mix and U. S. Geological Survey rock standard G-2. U. S. Geological Survey rock standard GSP-1 and N.B.S. coal fly ash SRM 1633 were analysed to evaluate the accuracy of the proposed method. Comparison of the mass spectral values with literature ones indicated a good agreement. The coefficient of variation obtained by replicate analysis of SRM 1633 was better than 25%. The proposed method was applied to the determination of rare earth elements in airborne particulate matter and dustfall collected on polystyrene filter and in dustjars, respectively. Results for the rare earth elements in the blank of glass fiber filter which was widely used for the collection of airborne particulate matter were also presented. (auth.)

Crystallographic and Spectroscopic Characterization of Americium Complexes Containing the Bis[(phosphino)methyl]pyridine-1-oxide (NOPOPO) Ligand Platform

Energy Technology Data Exchange (ETDEWEB)

Corbey, Jordan F. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Rapko, Brian M. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Wang, Zheming [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; McNamara, Bruce K. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Surbella, Robert G. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Pellegrini, Kristi L. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Schwantes, Jon M. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States

2018-02-06

Abstract The crystal structures of americium species containing a common multi-functional phosphine oxide ligand, reported for its ability to extract f elements from acidic solutions, namely 2,6-[Ph2P(O)CH2]2C5H3-NO, L, have finally been determined after over three decades of separations studies involving these species and their surrogates. The molecular compounds Am(L)(NO3)3, Am 1:1, and [Am(L)2(NO3)][NO3]2, Am 2:1, along with their neodymium and europium analogs were synthesized and characterized using single-crystal X-ray crystallography, attenuated total reflectance Fourier transform infrared (ATR) spectroscopy and luminescence spectroscopy to provide a comprehensive comparison with new and known analogous complexes.

The speciation of dissolved elements in aquatic solution. Radium and actinides

International Nuclear Information System (INIS)

Haesaenen, E.

1994-01-01

In the publication, the chemistry and speciation of radium, thorium, protactinium, uranium, neptunium, lutonium, americium and curium in ground-water environment is reviewed. Special attention is given to the transuranium elements, which have a central role in the repository of nuclear wastes. The most important methods used in the speciation of these elements is presented. The laser-induced methods, developed in the 1980's, are especially discussed. These have made it possible, e.g., to speciate the transuranium elements in their very low, actual repository ground-water concentrations (10-100 ng/l). (54 refs., 10 figs., 3 tabs.)

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

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.

The transmutation of americium: the Ecrix experiments in Phenix; Transmutation de l'americium: les experiences ecrix dans Phenix

Energy Technology Data Exchange (ETDEWEB)

Garnier, J.C.; Schmidt, N. [CEA Cadarache, Dept. d' Etudes des Combustibles (DEC/SESC), 13 - Saint-Paul-lez-Durance (France); Croixmarie, Y.; Ottaviani, J.P. [CEA Cadarache, Dept. d' Etudes des Combustibles (DEC/SPUA), 13 - Saint-Paul-lez-Durance (France); Varaine, F.; Saint Jean, C. de [CEA Cadarache, Dept. d' Etudes des Reacteurs (DER/SPRC), 13 - Saint-Paul-lez-Durance (France)

1999-07-01

The first americium transmutation experiment in a specific target in PHENIX will occur with the ECRIX-B and ECRIX-H experiments. Beside material testing, the objective is also to represent a concept of transmutation whose specificity is to enhance the kinetics of transmutation by using a moderated spectrum. The moderator materials will be {sup 11}B{sub 4}C and CaH{sub 2} for ECRIX-B and ECRIXH respectively, the irradiation conditions have been predicted for both the neutronics and thermal. The targets (MgO-AmO{sub X} pellets) are manufactured in the ATALANTE laboratory and the design is performed according to the PHENIX operating conditions. (authors)

Co-precipitation of plutonium(IV) and americium(III) from nitric acid-oxalic acid solutions with bismuth oxalate

International Nuclear Information System (INIS)

Pius, I.C.; Noronha, D.M.; Chaudhury, Satyajeet

2017-01-01

Co-precipitation of plutonium and americium from nitric acid-oxalic acid solutions with bismuth oxalate has been investigated for the removal of these long lived α-active nuclides from waste solutions. Effect of concentration of bismuth and oxalic acid on the co-precipitation of Pu(IV) from 3 M HNO_3 has been investigated. Similar experiments were also carried out from 3.75 M HNO_3 on co-precipitation of Am(III) to optimize the conditions of precipitation. Strong co-precipitation of Pu(IV) and Am(III) with bismuth oxalate indicate feasibility of treatment of plutonium and americium bearing waste solutions. (author)

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.

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)

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

Radiochemical separation and alpha-spectrometric determination of Americium in different matrixes

International Nuclear Information System (INIS)

Radenkovic, M.; Joksic, J.; Paligoric, D.

2009-01-01

A method of separation and alpha-spectrometric determination of americium, developed in VINCA Institute of Nuclear Sciences is described in the paper. The procedure is convenient to be used for 241 Am determination in environmental matrixes as well as samples of human origin if a very small concentrations are expected, using 243 Am as a tracer for radiochemical yield recovery. (author) [sr

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.

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

On possibility of transuranium element by the method of transport reactions

International Nuclear Information System (INIS)

Sinitsyna, G.S.; Krashenitsyn, G.N.; Shestakov, B.I.

1983-01-01

A possibility to use chemical transport reaction for separation of uranium, plutonium and some transplutonium elements is shown. The method is based on the use of the known plutonium property to form tetrachloride existing only in the gaseous phase in chlorine atmosphere, which is transported ever the temperature gradiept. Two ways of transport reaction realization - the method of flow and the method of diffusion in closed volume are tested. The experiments are made using specially synthesized plutonium dioxide, containing uranium, americium, curium, lanthanum, terbium, barium. Chlorination is realized by the mixture of chlorine and carbon tetrachloride at temperatures 723-953 K. Plutonium trichloride is deposited in the range 613-653 K, uranium - in the range 473-523 K, curium, americium, lanthanum, terbium, barium remain in the start zone if its temperature does not exceed 873 K

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

International Nuclear Information System (INIS)

Le Ba Thuan; Pham Quang Trung; Vu Lap Lai

2003-01-01

1. Yenphu rare earth ore concentrate treatment by alkali under pressure: On the base of studying mineral and chemical compositions of Yenphu rare earth ore concentrate containing 28% TREO and conditions for digestion of ore concentrate by alkali under pressure such as ore concentrate/ NaOH ratio, alkali concentration, pressure and temperature at bench scale (100 gram and 5 kg per batch), the optimal conditions for decomposition of REE ore concentrate have been determined. The yield of the decomposition stage is about 90%. The studies on alkali washing, REE leaching by HCl, pH for leaching process, and iron and radioactive impurities removing by Na 2 S + Na 2 PO 4 have been carried out. The obtained results show that mixture of Na 2 S 5% + Na2PO 4 1% is effective in iron and radioactive impurities removing. The obtained REE oxides get purity of > 99% and meet the need of solvent extraction (SX) individual separation of rare earth elements. The schema for recovery of REEs from Yenphu REE ore concentrate by alkali decomposition under high pressure has been proposed. 2. Fractionation of Yenphu rare earth mixture into subgroups by solvent extraction with PC88A: On the base of simulation program, the parameters for fractional process of rare earths mixture into subgroups by solvent extraction with PC88A have been proposed and determined by experimental verification on mixer-settler set. According to this process, rare earths mixture fractionated into yttrium and light subgroups. In their turn, the light subgroup was separated into light (La, Ce, Pr, Nd) and middle (Sm, Eu, Gd) subgroups. The average yield of the process reached value > 95%. The composition of light subgroup meets the needs for individual separation of Gd, Eu, and Sm. 3. Separation and purification of yttrium: The process for recovery of yttrium consists of two stages: upgrade to get high quality Y concentrate by PC88A and purification by Aliquat 336 in NH 4 SCN-NH 4 Cl medium. The process parameter for

A problem in gravimetric method for the determination of rare earth elements as oxide after the fluoride separation

International Nuclear Information System (INIS)

Takada, Kunio

1979-01-01

For the gravimetric determination of lanthanum, it was precipitated as fluoride and converted to oxide by igniting (ca. 930 0 C) in a town gas flame. However, the oxidation of lanthanum fluoride by ignition was incomplete, the major part of the precipitate being converted to oxyfluoride (LaOF) and a mixture of oxide and oxyfluoride resulted. Therefore, analytical results were generally (5 -- 7)% higher than theoretically expected. The lanthanum fluoride became converted into the oxide by repeating ignition (ca. 1070 0 C) three times, each for (30 -- 40)min. However, the weight was lower than that of the corresponding sesquioxide, La 2 O 3 . Except for ytterbium and lutetium, gravimetric results as oxides for the other rare earth elements (Y, Pr, Nd, Sm, Eu and Gd) were higher than theoretical values. Therefore, the precipitation of the rare earth elements as fluoride and the subsequent determination as oxide by ignition of the fluoride could not be recommended as the gravimetric method for the rare earths. In order to obtain accurate results for major to minor amounts of the rare earth elements, an EDTA titration at pH 6 should be used after the dissolution of fluoride in acid, if the fluoride precipitation separation is involved. (author)

Geochemical processes assessed by Rare Earth Elements fractionation at “Laguna Verde” acidic-sulphate crater lake (Azufral volcano, Colombia)

International Nuclear Information System (INIS)

Inguaggiato, Claudio; Burbano, Viviana; Rouwet, Dmitri; Garzón, Gustavo

2017-01-01

The geochemical behaviour of major elements, Fe, Al, Mn, and Rare Earth Elements (REE) was investigated in the “Laguna Verde” acidic crater lake of Azufral volcano (Colombia). The cold lake water (T close to 10 °C) is sulphate-dominated, due to absorption and oxidation of H_2S (pH 2.1–2.7, Eh 196–260 mV), and Na-enriched (Total Dissolved Solids 0.79 g L"−"1). The total amount of REE dissolved in the lake ranges from 3.3 to 9.1 ppb. The REE patterns normalized to the local rocks show a Light Rare Earth Elements (LREE) depletion quite constant in the 15 samples. Similar patterns were already found in the acidic sulphate springs of Nevado del Ruiz volcano-hydrothermal system, caused by the precipitation of alunite and jarosite, absorbing LREE and hence removing them from solution. Alunite and jarosite minerals are not oversaturated at chemical-physical conditions within the lake itself, but alunite becomes oversaturated for temperatures above ≈100 °C, reigning in the underlying hydrothermal system. Water temperatures close to 75 °C were found in the northern part of the lake. Coupling the distribution of REE in lake water (LREE depleted) and the saturation indexes, we suggest that the distribution of REE in the lake water is the result of the alunite precipitation in the northern part of the lake and/or in the deeper hydrothermal system. The acidic hydrothermal fluids mobilize the REE with contents up to ≈5 orders of magnitude higher than seawater; acidic-hydrothermal systems, such as acidic crater lakes, can hence be considered potential REE “reservoirs”. - Highlights: • Acidic crater lakes can be considered potential Rare Earth Elements reservoirs. • Alunite precipitation removes Light Rare Earth Elements. • Rare Earth Elements identify geochemical processes in volcano-hydrothermal systems.

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

Mass separation of rare-earth elements by a high-temperature thermal ion source coupled with a He-jet system

International Nuclear Information System (INIS)

Kawase, Y.; Okano, K.; Aoki, K.

1987-01-01

By using a high-temperature thermal ion source coupled to a He-jet system, neutron-rich isotopes of rare-earth elements such as cerium, praseodymium, neodymium and promethium produced by the thermal-neutron fission of /sup 235/U were ionized and successfully separated. The temperature dependence of the ionization efficiency has been measured and found to be explained qualitatively by the vapour pressure of the relevant elements. The characteristic temperature dependence of the ionization efficiency has been utilized for Z-identification of several isobars of rare-earth elements. The heaviest isotopes of neodymium and promethium, /sup 155/Nd and /sup 156/Pm, have recently been identified

Adsorption-Desorption Characteristics of Plutonium and Americium with Sediment Particles in the Estuarine Environment

International Nuclear Information System (INIS)

Murray, C.N.; Fukai, R.

1976-01-01

The particle formation of plutonium and americium, their adsorption onto fresh water sediments and the desorption from the sediments in sea water were studied in the Laboratory under simulated river-estuary conditions, using γ-emitting plutonium-237 and americium-241. The results of the experiments show that the particle formation of plutonium depends on its valence states, on pH and on the salinity of the medium. For river water at pH4, some 25%, 20% and 30% of the added 237 Pu was in particulate form, larger than 0.45pm, for Pu (III), Pu (IV) and Pu (VI), respectively, while 65%, 90% and 50% of the respective valence states was associated with particles at pH 8. In sea water the general pattern remains similar, although Pu (VI) is more soluble in sea water owing to higher ligand concentrations for carbonate and bicarbonate complexes. The pH-dependency of particle formation of Am (III) is more steep than that of plutonium and seems to be influenced by colloidal substances occurring in the experimental media. The adsorption-desorption characteristics of plutonium and americium with the sediment in river water as well as sea water reflect the characteristics of their particle formation, being dependent upon such properties as valence states, the pH and salinity of the medium. A sewage effluent added to the media has small but measurable effects on the adsorption-desorption processes of plutonium. (author)

Determination of rare earths and traces of other elements by neutron activation analysis

International Nuclear Information System (INIS)

Atalla, L.T.; Mantovani, M.S.M.; Marques, L.S.

A complete methodology for a multielemental analysis in geological material using the neutron activation technique was developed. 21 trace elements (9 of which are rare earths) were determined using thermal and epithermal neutron irradiations. Instrumetnal and radiochemical processing, applied to BCR-1 and G-2 geological standards, are described. Statistical tests carried out on G-2 data show an error smaller than 15% referring to all elements except Cr, Sb and Yb. The observed differences between are discussed. The good precision attained in this method is confirmed by its application to BCR-1 standard, which presents errors smaller than 4% for all elements except Nd, due to its intrinsic properties. The results from the present work are compared with those from other laboratories. (C.L.B.) [pt

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.

Rare earth element mineralogy, geochemistry, and preliminary resource assessment of the Khanneshin carbonatite complex, Helmand Province, Afghanistan

Science.gov (United States)

Tucker, Robert D.; Belkin, Harvey E.; Schulz, Klaus J.; Peters, Stephen G.; Buttleman, Kim P.

2011-01-01

There is increased concern about the future availability of rare earth elements (REE) because of China's dominance as the supplier of more than 95 percent of world REE output, their decision to restrict exports of rare earth products, and the rapid increase in world-wide consumption of rare earth product. As a result, countries such as the United States, Japan, and member nations of the European Union face a future of tight supplies and high prices for rare earth products unless other sources of REE are found and developed (Long and others, 2010; U.S. Geological Survey, 2011, p. 128-129, 184-185). We report and describe a significant new deposit of light rare earth elements (LREE), estimated at 1 Mt, within the Khanneshin carbonatite complex of south Afghanistan. The potential resource is located in a remote and rugged part of the igneous complex in a region previously identified by Soviet geologists in the 1970s. This report reviews the geologic setting of LREE deposit, presents new geochemical data documenting the grade of LREE mineralization, briefly describes the mineralogy and mineralogical associations of the deposit, and presents a preliminary estimate of LREE resources based on our current understanding of the geology.

Physics of plutonium and americium recycling in PWR using advanced fuel concepts

International Nuclear Information System (INIS)

Hourcade, E.

2004-01-01

PWR waste inventory management is considered in many countries including Frances as one of the main current issues. Pu and Am are the 2 main contents both in term of volume and long term radio-toxicity. Waiting for the Generation IV systems implementation (2035-2050), one of the mid-term solutions for their transmutation involves the use of advanced fuels in Pressurized Water Reactors (PWR). These have to require as little modification as possible of the core internals, the cooling system and fuel cycle facilities (fabrication and reprocessing). The first part of this paper deals with some neutronic characteristics of Pu and/or Am recycling. In a second part, 2 technical solutions MOX-HMR and APA-DUPLEX-84 are presented and the third part is devoted to the study of a few global strategies. The main neutronic parameters to be considered for Pu and Am recycling in PWR are void coefficient, Doppler coefficient, fraction of delayed neutrons and power distribution (especially for heterogeneous configurations). The modification of the moderation ratio, the opportunity to use inert matrices (targets), the optimisation of Uranium, Plutonium and Americium contents are the key parameters to play with. One of the solutions (APA-DUPLEX-84) presented here is a heterogeneous assembly with regular moderation ratio composed with both target fuel rods (Pu and Am embedded in an inert matrix) and standard UO 2 fuel rods. An EPR (European Pressurised Reactor) type reactor, loaded only with assemblies containing 84 peripheral targets, can reach an Americium consumption rate of (4.4; 23 kg/TWh) depending on the assembly concept. For Pu and Am inventories stabilisation, the theoretical fraction of reactors loaded with Pu + Am or Pu assemblies is about 60%. For Americium inventory stabilisation, the fraction decreases down to 16%, but Pu is produced at a rate of 18.5 Kg/TWh (-25% compared to one through UOX cycle)

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.

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.

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.

Contrasts between the marine and freshwater biological interactions of plutonium and americium

International Nuclear Information System (INIS)

Livingston, H.D.; Bowen, V.T.

1975-01-01

Whether in lakes or the oceans the transuranic elements plutonium and americium are taken up by marine organisms, with concentration factors that would class them as nice, typical heavy metals. There is no evidence for strong, widespread discrimination against the transuranics by either plant or animal absorptive surfaces. In both freshwater and marine situations the major reservoir of Pu and Am soon becomes the sediments, and organisms are more exposed to uptake of these nuclides the closer is their ecological involvement with the sediments. Although there is little evidence that this can be an ionic strength effect, it does appear that Pu may be somewhat more available, biologically, in marine environments, and Am, conversely, in fresh water. We incline to the belief that details of these behaviors are usually controlled by local availability of organic complexers. No compelling evidence exists of increase in Pu concentration at higher levels of food chains; in marine situations this appears true of Am as well, but a few data suggest that in fresh water fish there is a progressive increase, in higher trophic levels, in the ratio Am to Pu. Although marine and fresh water biogeochemistries of transuranics are much more similar than we had expected, it will generally be dangerous to extrapolate from one to the other. In both systems there appears to us no question that we are observing real element biogeochemistry, not the redistribution of inert, labelled, fallout fragments

Rare earth element patterns in biotite, muscovite and tourmaline minerals

International Nuclear Information System (INIS)

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

1986-01-01

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

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.

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...

Multielement determination of rare earth elements by liquid chromatography/inductively coupled plasma atomic emission spectrometry

International Nuclear Information System (INIS)

Sawatari, Hideyuki; Asano, Takaaki; Hu, Xincheng; Saizuka, Tomoo; Itoh, Akihide; Hirose, Akio; Haraguchi, Hiroki

1995-01-01

The rapid determination of rare earth elements (REEs) has been investigated by an on-line system of high performance liquid chromatography/multichannel inductively coupled plasma atomic emission spectrometry. In the present system, all REEs could be detected simultaneously in a single chromatographic measurement without spectral interferences. Utilizing a cation exchange column and 2-hydroxy-2-methylpropanoic acid aqueous solution as the mobile phase, the detection limits of 0.4-30 ng ml -1 for all REEs were obtained. The system was applied to the determination of REEs in geological standard rock samples and rare earth impurities in high purity rare earth oxides. The REEs in standard rocks could be determined by the present HPLC/ICP-AES system without pretreatment after acid digestion, although the detection limits were not sufficient for the analysis of rare earth oxides. (author)

Studies of transport pathways of Th, U, rare earths, Ra-228, and Ra-226 from soil to plants and farm animals: Final progress report, 1983-1988

Energy Technology Data Exchange (ETDEWEB)

Linsalata, P

1988-07-01

This report consists of three parts. Part 1 discusses a field study conducted in an area of enhanced, natural radioactivity to assess the soil to edible vegetable concentration ratios (CR = concentration in dry vegetable/concentration in dry soil) of Th-232, Th-230, Ra-226, Ra-228, and the light rare earth elements (REE's), La, Ce, and Nd. Twenty-eight soil, and approximately 42 vegetable samples consisting of relatively equal numbers of seven varieties, were obtained from 11 farms on the Pocos de Caldas Plateau in the state of Minas Gerais, Brazil. This region is the site of a major natural analogue study to assess the mobilization and retardation processes affecting thorium and the REE's at the Morro do Ferro ore body, and uranium series radionuclides at the Osamu Utsumi open pit uranium mine. Thorium (IV) serves as a chemical analogue for quadrivalent plutonium, the light REE's (III) as chemical analogues for trivalent americium and curium, and uranium (VI) as an analogue for transuranics with stable oxidation states above IV, e.g., Pu(VI). Part 2 includes our final measurement results for naturally occurring light rare earth elements (REE's include La, Ce, Nd, and SM), U-series and Th-series radionuclides in adult farm animal tissues, feeds and soils. Our findings on soil-to-tissue concentration ratios (CR's) and the comparative behavior of these elements in farm animals raised under natural conditions by local farmers are presented. Part 3 summarizes our findings to date on the distribution and mobilization of Th-232, light rare earth elements (LREE), U-238 and Ra-228 in the MF basin. Estimates of first order, present day, mobilization rate constants resulting from ground water solubilization and seepage/stream transport are calculated using revised inventory estimates for the occurrence of these elements in the ore body and annual flux estimates for the transport of these elements away from the ore body. 151 refs., 20 figs., 40 tabs.

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

Distribution of rare earth elements in an alluvial aquifer affected by acid mine drainage: the Guadiamar aquifer (SW Spain)

International Nuclear Information System (INIS)

Olias, M.; Ceron, J.C.; Fernandez, I.; Rosa, J. de la

2005-01-01

This work analyses the spatial distribution, the origin, and the shale-normalised fractionation patterns of the rare earth elements (REE) in the alluvial aquifer of the Guadiamar River (south-western Spain). This river received notoriety in April 1998 for a spill that spread a great amount of slurry (mainly pyrites) and acid waters in a narrow strip along the river course. Groundwaters and surface waters were sampled to analyse, among other elements, the REEs. Their spatial distribution shows a peak close to the mining region, in an area with low values of pH and high concentrations of sulphates and other metals such as Zn, Cu, Co, Ni, Pb, and Cd. The patterns of shale-normalised fractionation at the most-contaminated points show an enrichment in the middle rare earth elements (MREE) with respect to the light (LREE) and heavy (HREE) ones, typical of acid waters. The Ce-anomaly becomes more negative as pH increases, due to the preferential fractionation of Ce in oxyhydroxides of Fe. - Pollution of the aquifer with rare earth elements is documented at a site of a major spill from a mining operation

Actinide elements in aquatic and terrestrial environments

International Nuclear Information System (INIS)

Bondietti, E.A.

1978-01-01

Progress is reported in terrestrial ecology studies with regard to plutonium in biota from the White Oak Creek forest; comparative distribution of plutonium in two forest ecosystems; an ecosystem model of plutonium dynamics; actinide element metabolism in cotton rats; and crayfish studies. Progress is reported in aquatic studies with regard to transuranics in surface waters, frogs, benthic algae, and invertebrates from pond 3513; and radioecology of transuranic elements in cotton rats bordering waste pond 3513. Progress is also reported in stability of trivalent plutonium in White Oak Lake water; chemistry of plutonium, americium, curium, and uranium in pond water; uranium, thorium, and plutonium in small mammals; and effect of soil pretreatment on the distribution of plutonium

Extraction and separation of Am and rare earth elements in HNO3 solution with P507-sulphonating kerosene

International Nuclear Information System (INIS)

Li Zhenhu; Jiao Rongzhou; Zhu Yongjun

1994-01-01

A study has been made of the extraction equilibrium of Am(III) and rare earth elements (III) in HNO 3 solution with P507-sulphonating kerosene. It has been found that this equilibrium depends on saponification ratio of P507, feed acidity, metal concentration as well as phase ratio. The extraction ability in order is La< Ce< Am< Pr< Nd< Sm. The model of distribution ratio has been founded. The agreement for calculated and experimental values of distribution ratio is fairly good. These values can be used to design the extraction and separation process of Am and rare earth elements

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...

Concentration levels of rare-earth elements and thorium on plants from the Morro de Ferro environment as an indicator for the biological availability of transuranium elements

International Nuclear Information System (INIS)

Miekeley, N.; Casartelli, E.A.; Dotto, R.M.

1994-01-01

Plants and soils from a natural thorium and rare-earth element occurrence (Morro do Ferro, Brazil) were analyzed by alpha spectrometry (Th) and ICP-AES (REE), after pre-concentration of the elements by solvent extraction, co-precipitation and ion exchange procedures. Leaching experiments with humic acid solutions and different soils were performed to estimate the fraction of elements biologically available. High concentrations of the light rare-earth elements (LREE) and of Th, reaching some hundreds of μg/g-ash, were measured in plant leaves from the areas of the highest concentration of these elements in soil and in near-surface waters. Chondrite normalized REE plots of plant leaves and corresponding soils are very similar, suggesting that there is no significant fractionation between the REE during uptake from the soil solution and incorporation into the leaves. However, Ce-depletion was observed for some plant species, increasing for Solanum ciliatum in the sequence: leaves -3 to 10 -2 . Leaching experiments confirmed the importance of humic acid complexation for the bio-uptake of Th and REE and further showed that only a very small fraction of these elements in soil is leachable. The implications of these results on the calculated CR's will be discussed. (author) 26 refs.; 5 figs.; 5 tabs

Transfer of environmental plutonium and americium across the human gut

International Nuclear Information System (INIS)

Hunt, G.J.; Leonard, D.R.P.; Lovett, M.B.

1989-01-01

Following the ingestion of winkles obtained from a coastal area near Sellafield nuclear reprocessing plant, a group of volunteers provided urine for the next 7 days to be analysed for plutonium and americium. From this, estimates of the intake and gut transfer factors for these isotopes were determined. Preliminary estimates of gut transfer factors from a previous study by the same authors were then re-interpreted and combined with the results from the present study. (UK)

Total and Compound Formation Cross Sections for Americium Nuclei: Recommendations for Coupled-Channels Calculations

Energy Technology Data Exchange (ETDEWEB)

Escher, J. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-04-11

Calculations for total cross sections and compound-nucleus (CN) formation cross sections for americium isotopes are described, for use in the 2017 NA-22 evaluation effort. The code ECIS 2006 was used in conjunction with Frank Dietrich's wrapper `runtemplate'.

Elemental and mineralogical study of earth-based pigments using particle induced X-ray emission and X-ray diffraction

International Nuclear Information System (INIS)

Nel, P.; Lynch, P.A.; Laird, J.S.; Casey, H.M.; Goodall, L.J.; Ryan, C.G.; Sloggett, R.J.

2010-01-01

Artwork and precious artefacts demand non-destructive analytical methodologies for art authentication, attribution and provenance assessment. However, structural and chemical characterisation represents a challenging problem with existing analytical techniques. A recent authentication case based on an Australian Aboriginal artwork, indicate there is substantial benefit in the ability of particle induced X-ray emission (PIXE), coupled with dynamic analysis (DA) to characterise pigments through trace element analysis. However, this information alone is insufficient for characterising the mineralogical residence of trace elements. For this reason a combined methodology based on PIXE and X-ray diffraction (XRD) has been performed to explore the benefits of a more comprehensive data set. Many Aboriginal paintings and artefacts are predominantly earth pigment based. This makes these cultural heritage materials an ideal case study for testing the above combined methodological approach on earth-based pigments. Samples of synthetic and naturally occurring earth-based pigments were obtained from a range of sources, which include Indigenous communities within Australia's Kimberley region. PIXE analyses using a 3 MeV focussed proton beam at the CSIRO nuclear microprobe, as well as laboratory-based XRD was carried out on the above samples. Elemental signature spectra as well as mineralogical data were used to assess issues regarding synthetic and naturally occurring earth pigments with the ultimate aim of establishing provenance.

Mycoremediation. The study of transfer factor for plutonium and americium uptake from the ground

International Nuclear Information System (INIS)

Dusan Galanda; Lubomir Matel; Jana Strisovska; Silvia Dulanska

2014-01-01

In our scientific research we have monitored mycoremediation's properties of oyster mushrooms in cultivation on the soil what is contaminated by solutions with radioactive isotopes of 239 Pu and 241 Am with known activity. We monitored specific activities of absorbed radionuclides in fruiting bodies and chemical forms of radionuclides which were compared to calculated specific activities of two background samples of oyster mushrooms intended for consumer purpose. We determined distributive coefficients between the ground and the fruiting body of oyster mushrooms. The average value which was obtained for the transfer factor for plutonium was 0.72 and for americium 3.97. To evaluate a quantity of absorbed radionuclides we used a method of liquid extraction. The emitting alpha radiation of alpha radionuclides was detected by spectrometry. For defining individual fractions of plutonium and americium that are contained in mushroom bodies was used the sequential leaching method. (author)

High-purity germanium detection system for the in vivo measurement of americium and plutonium

International Nuclear Information System (INIS)

Tyree, W.H.; Falk, R.B.; Wood, C.B.; Liskey, R.W.

1976-01-01

A high-purity germanium (HPGe) array, photon-counting system has been developed for the Rocky Flats Plant Body-Counter Medical Facility. The newly improved system provides exceptional resolutions of low-energy X-ray and gamma-ray spectra associated with the in vivo deposition of plutonium and americium. Described are the operational parameters of the system and some qualitative results illustrating detector performance for the photon emissions produced from the decay of plutonium and americium between energy ranges from 10 to 100 kiloelectron volts. Since large amounts of data are easily generated with the system, data storage, analysis, and computer software developments continue to be an essential ingredient for processing spectral data obtained from the detectors. Absence of quantitative data is intentional. The primary concern of the study was to evaluate the effects of the various physical and electronic operational parameters before adding those related entirely to a human subject

Carbon footprint assessment of recycling technologies for rare earth elements: A case study of recycling yttrium and europium from phosphor.

Science.gov (United States)

Hu, Allen H; Kuo, Chien-Hung; Huang, Lance H; Su, Chao-Chin

2017-02-01

Rare earth elements are key raw materials in high-technology industries. Mining activities and manufacturing processes of such industries have caused considerable environmental impacts, such as soil erosion, vegetation destruction, and various forms of pollution. Sustaining the long-term supply of rare earth elements is difficult because of the global shortage of rare earth resources. The diminishing supply of rare earth elements has attracted considerable concern because many industrialized countries regarded such elements as important strategic resources for economic growth. This study aims to explore the carbon footprints of yttrium and europium recovery techniques from phosphor. Two extraction recovery methods, namely, acid extraction and solvent extraction, were selected for the analysis and comparison of carbon footprints. The two following functional units were used: (1) the same phosphor amounts for specific Y and Eu recovery concentrations, and (2) the same phosphor amounts for extraction. For acid extraction method, two acidic solutions (H 2 SO 4 and HCl) were used at two different temperatures (60 and 90°C). For solvent extraction method, acid leaching was performed followed by ionic liquid extraction. Carbon footprints from acid and solvent extraction methods were estimated to be 10.1 and 10.6kgCO 2 eq, respectively. Comparison of the carbon emissions of the two extraction methods shows that the solvent extraction method has significantly higher extraction efficiency, even though acid extraction method has a lower carbon footprint. These results may be used to develop strategies for life cycle management of rare earth resources to realize sustainable usage. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

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.

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.

Effect of 241-americium on bone marrow stroma

International Nuclear Information System (INIS)

Heuvel, R. van den

1990-01-01

The regulation of haemopoiesis occurs via complex interactions between the stroma and the haemopoietic cells. An attempt to further clarifying the mechanisms and the exact role of the stroma in the regulation was made in a study. Results revealed that the murine bone marrow stromal cells are highly radiosensitive after injection with 241-americium and can thus be considered as a target population after internal contamination. In addition, observations are made which may be important for risk estimation for the developing animal and during pregnancy. Contamination in utero and by lactation shows persistent damage up to 1 year after contamination at an average annual dose of 5 cGy. (author)

The extraction of lanthanides and americium by benzyldiakylamines and benzyltrialkylammonium nitrates from the nitrate solutions; structure and aggregation of their salts

International Nuclear Information System (INIS)

Jedinakova, V.; Zilkova, J.; Dvorak, Z.; Vojtiskova, M.

1982-01-01

Benzyldialkylamine and benzyltrialkylammonium nitrates were used for the extraction of lanthanides and americium from aqueous nitrate solutions. The dependence of the extraction performance for Ln(III) and Am(III) on the concentration of nitric acid, the kind and concentration of salting-out agents in the aqueous phase, and the kind of solvent were investigated. The extraction of Am(III) is compared with the extraction of lanthanides. The difference in distribution coefficients for lanthanides and americium can be utilized for the separation of lanthanides and americium. Using vapor phase osmometry and cryoscopy the association of these compounds was measured at 5.5deg, 25deg and 37deg C, allowing rough estimates of ΔH and ΔS for the formation of the aggregates, monomers in the case of benzyldiethylamine, benzyldibutylamine, benzyldihexylamine and benzyldioctylamine, tetramers for the benzyldibutylamine nitrate and tetramers for benzyldimethyldodecylammonium nitrate. (author)

A survey of 16 rare Earth elements in the major foods in China.

Science.gov (United States)

Jiang, Ding Guo; Yang, Jie; Zhang, Shuo; Yang, Da Jin

2012-06-01

The aim of this survey was to investigate the level of contamination of the most consumed foods in China with 16 rare earth elements (REEs), and to provide the basic data for establishing and revising food safety standards for REEs. Sixteen REEs in foods were measured by inductively coupled plasma-mass spectrometry (ICP-MS) in the labs of the Centers for Disease Control and Prevention of four provinces and two municipalities, during 2009-2010. 1 231 samples were analyzed and 19 121 concentration data of 16 REEs were collected. The REEs levels in the investigated foods varied significantly. The concentrations of cerium (Ce), dysprosium (Dy), yttrium (Y), lanthanum (La), and neodymium (Nd) were relatively high, while the remaining eleven REEs were at low levels. The mean values of total rare earth element oxides (REOs) in cereals, fresh vegetables, fresh aquatic products, fresh meats and eggs varied from 0.052 mg/kg to 0.337 mg/kg. 16 REEs in the major foods were at very low contamination levels in the investigated regions. Copyright © 2012 The Editorial Board of Biomedical and Environmental Sciences. Published by Elsevier B.V. All rights reserved.

Determination of experimental conditions for the analysis of rare-earth elements by X-ray fluorescence spectrometry. Application to oxalates and potassium sulphate matrices

International Nuclear Information System (INIS)

Bayon Fuentes, A.; Bermudez Polonio, J.

1969-01-01

A previous theoretical and experimental study is carried out in order to analyze the rare earths elements by X-ray florescence spectrometry. All possible spectral interferences are considered. The working conditions for each element were selected, taking into account the peak/background ratio values for the following parameters: tungsten, molybdenum and chromium targets, current and voltage, analyzing crystals, and scintillation and flow proportional counters. Calibration curves were plotted showing the concentration of rare earths elements in oxalates and potassium sulphate matrices, and the theoretical detection limits for each element: are calculated. (Author) 8 refs

Experimental evidence of the impact of rare-earth elements on particle growth and mechanical behaviour of silicon nitride

International Nuclear Information System (INIS)

Satet, Raphaelle L.; Hoffmann, Michael J.; Cannon, Rowland M.

2006-01-01

The impact of various rare-earth and related doping elements (R = Lu, Sc, Yb, Y, Sm, La) on the grain growth anisotropy and the mechanical properties of polycrystalline β-silicon nitride ceramics has been studied. Model experiments, in which Si 3 N 4 particles can grow freely in an R-Si-Mg-oxynitride glass matrix, show that, with increasing ionic radius of the additive, grain anisotropy increases due to non-linear growth kinetics. Toughness and strength are affected by the rare-earth element. Samples of equivalent grain sizes and morphologies yield an increasing toughness with increasing ion size of the R 3+ , reflecting an increasingly intergranular crack path. These samples are also strong and flaw tolerant, but the trends of strength and toughness do not exactly match. The choice of the rare-earth is essential to tailor microstructure, interfacial strength and mechanical properties. However, somewhat different trends for properties from IIIb and lanthanide additives indicate that more than the R 3+ size (i.e., purely ionic bond strength between R 3+ and its neighbours) is important. The electronic structure of the R-element is responsible for the type of dopant adsorption and the properties of the interface

Consideration of the effect of lymph-node deposition upon the measurement of plutonium and americium in the lungs

International Nuclear Information System (INIS)

Falk, R.B.; Lagerquist, C.R.

1975-01-01

Measurement of an inhaled radionuclide by external photon counting includes quantities which may be contained in lymph nodes, as well as quantities in the lungs. An overestimate of the lung burden can result, if a portion of the radionuclide were present in the lymph nodes. This problem is analyzed with respect to the measurement of inhaled plutonium containing plutonium-241 and americium-241, when americium-241 has been used as a tracer for the plutonium. Equations are derived which yield the amounts of americium and of plutonium in the lungs and in the lymph nodes as a function of time after exposure and for various translocation and retention parameters. Count histories (count profiles) of actual exposure cases are compared with calculated count profiles in order to gain insight into possible values of the translocation and retention parameters. Comparison is also made with calculated count profiles using values of translocation and retention parameters recommended by the International Commission on Radiological Protection (ICRP) for use with the Task Group Lung Model. The magnitude of the possible overestimate (error factor) was calculated for combinations o []parameters which yielded matches to the observed count histories. (auth)

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

Energy Technology Data Exchange (ETDEWEB)

Facetti, J F; Prats, M [Asuncion Nacional Univ. (Paraguay). Inst. de Ciencias

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.

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

Experiments comparing the uptake of americium from chloride media using extraction chromatography

International Nuclear Information System (INIS)

FitzPatrick, J.R.; Schake, B.S.; Schulte, L.D.; Martinez, B.T.; Salazar, R.R.

1995-01-01

Clean-up of actinide effluent waste steams is of increasing importance at the Los Alamos Plutonium Facility, TA-55, and removing the actinide elements to very low levels allows less radioactivity to go the Los Alamos National Laboratory Water Treatment Facility, TA-50, thus reducing the number of drums of TRU waste. Americium (Am) is a difficult element to remove from chloride media because the +3 state is difficult to oxidize and chelating resins work better with elements such as plutonium which are more readily oxidized to the +4 and/or +6 state. Currently in hydrochloric acid (HC1) media, the acidic liquid waste is neutralized with potassium hydroxide to precipitate the metal hydroxides, before disposal to TA-50. This process is not very efficient. The removal of Am from chloride media was compared using a series of resins, some commercial and some made in our laboratory, using different percentages by weight of octyl(phenyl)-N,N-diiso- butylcarbamoyl-methylphosphine oxide (CMPO ) along with diamyl amylphosphonate (DAAP) or tributyl phosphate (TBP) as diluents. Resins were also made with no added diluent. Early comparisons using small-scale contact studies with 0.5 grams of resin in 0.1M-12M HC1, and subsequent small-scale flow experiments show a trend in which Am uptake is proportional to the amount of CMPO on the resins and the diluent plays a minor role in the uptake of Am from these solutions. Redox chemistry effects were also investigated. From these studies, it is possible to determine the best conditions for the removal of Am from HC1 media thus reducing the gross alpha content of the waste stream by a factor of 10-100 which reduces the number of barrels of waste produced at the Water Treatment Facility

On the influence of the americium isotopic vector on the cooling time of minor actinides bearing blankets in fast reactors

Directory of Open Access Journals (Sweden)

Kooyman Timothée

2018-01-01

Full Text Available In the heterogeneous minor actinides transmutation approach, the nuclei to be transmuted are loaded in dedicated targets often located at the core periphery, so that long-lived heavy nuclides are turned into shorter-lived fission products by fission. To compensate for low flux level at the core periphery, the minor actinides content in the targets is set relatively high (around 20 at.%, which has a negative impact on the reprocessing of the targets due to their important decay heat level. After a complete analysis of the main contributors to the heat load of the irradiated targets, it is shown here that the choice of the reprocessing order of the various feeds of americium from the fuel cycle depends on the actual limit for fuel reprocessing. If reprocessing of hot targets is possible, it is more interesting to reprocess first the americium feed with a high 243Am content in order to limit the total cooling time of the targets, while if reprocessing of targets is limited by their decay heat, it is more interesting to wait for an increase in the 241Am content before loading the americium in the core. An optimization of the reprocessing order appears to lead to a decrease of the total cooling time by 15 years compared to a situation where all the americium feeds are mixed together when two feeds from SFR are considered with a high reprocessing limit.

Sorption of plutonium and americium on repository, backfill and geological materials relevant to the JNFL low-level radioactive waste repository at Rokkasho-Mura

International Nuclear Information System (INIS)

Baston, G.M.N.; Berry, J.A.; Brownsword, M.; Heath, T.G.; Tweed, C.J.; Williams, S.J.

1995-01-01

An integrated program of batch sorption experiments and mathematical modeling has been carried out to study the sorption of plutonium and americium on a series of repository, backfill and geological materials relevant to the JNFL low-level radioactive waste repository at Rokkasho-Mura. The sorption of plutonium and americium on samples of concrete, mortar, sand/bentonite, tuff, sandstone and cover soil has been investigated. In addition, specimens of bitumen, cation and anion exchange resins, and polyester were chemically degraded. The resulting degradation product solutions, alongside solutions of humic and isosaccharinic acids were used to study the effects on plutonium sorption onto concrete, sand/bentonite and sandstone. The sorption behavior of plutonium and americium has been modeled using the geochemical speciation program HARPHRQ in conjunction with the HATCHES database

High contents of rare earth elements (REEs) in stream waters of a Cu-Pb-Zn mining area.

Science.gov (United States)

Protano, G; Riccobono, F

2002-01-01

Stream waters draining an old mining area present very high rare earth element (REE) contents, reaching 928 microg/l as the maximum total value (sigmaREE). The middle rare earth elements (MREEs) are usually enriched with respect to both the light (LREEs) and heavy (HREEs) elements of this group, producing a characteristic "roof-shaped" pattern of the shale Post-Archean Australian Shales-normalized concentrations. At the Fenice Capanne Mine (FCM), the most important base metal mine of the study area, the REE source coincides with the mine tailings, mostly the oldest ones composed of iron-rich materials. The geochemical history of the REEs released into Noni stream from wastes in the FCM area is strictly determined by the pH, which controls the REE speciation and in-stream processes. The formation of Al-rich and mainly Fe-rich flocs effectively scavenges the REEs, which are readily and drastically removed from the solution when the pH approaches neutrality. Leaching experiments performed on flocs and waste materials demonstrate that Fe-oxides/oxyhydroxides play a key role in the release of lanthanide elements into stream waters. The origin of the "roof-shaped" REE distribution pattern as well as the peculiar geochemical behavior of some lanthanide elements in the aqueous system are discussed.

National low-level waste management program radionuclide report series, Volume 14: Americium-241

International Nuclear Information System (INIS)

Winberg, M.R.; Garcia, R.S.

1995-09-01

This report, Volume 14 of the National Low-Level Waste Management Program Radionuclide Report Series, discusses the radiological and chemical characteristics of americium-241 ( 241 Am). This report also includes discussions about waste types and forms in which 241 Am can be found and 241 Am behavior in the environment and in the human body

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

Incorporation of plutonium, americium and curium into the Irish Sea seabed by biological activity

Energy Technology Data Exchange (ETDEWEB)

Kershaw, P J; Swift, D J; Pentreath, R J; Lovett, M B

1984-12-01

Bioturbation was considered as a potentially significant mechanism for the incorporation of long-lived radionuclides into the seabed and in particular the activities of a large echiuran Maximulleria lankesteri. Radionuclides of the transuranium elements plutonium, americium and cirium are discharged into the Irish Sea under authorization as part of the low-level liquid effluent from the British Nuclear Fuels plc reprocessing plant at Sellafield, Cumbria, England. The distribution of Pu-239, 240, Pu-238, Am-241, Cm-244 and Cm-242 concentrations and the Pu-239, 240/Pu-238 quotient in samples taken in April and May 1983 from the sediment surface, burrow linings, sediments adjacent to burrows, and the gut contents and body of a large M. lankesteri clearly indicate that bioturbation is responsible, at least in part, for the incorporation of these radionuclides to depths of up to 140 cm. This area of sediments represents a significant present-day sink, but the permanence of this sink and the likelihood that radioactivity will be remobilized and be returned to man, depends on a large number of factors. 15 references, 18 figures.

Determination of americium and plutonium in autopsy tissue: methods and problems

International Nuclear Information System (INIS)

Boyd, H.A.; Eutsler, B.C.; McInroy, J.F.

1979-01-01

The current methods used by the tissue analysis program at LASL for the determination of americium and plutonium in autopsy tissue are described. Problems affecting radiochemical yield are discussed. Included are problems associated with sample preparation, separation of plutonium from large amounts of bone ash, and reagent contamination. The average 242 Pu tracer yield for 1800 Pu determinations is 78 +- 12%. The average 242 Am tracer yield is 85 +- 7% for 40 determinations

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

Sensitive method for the determination of rare earth elements by radioisotope-excited XRF employing a high purity germanium detector in optimized geometry

International Nuclear Information System (INIS)

Lal, M.; Joseph, D.; Patra, P.K.; Bajpal, H.N.

1993-01-01

A close-coupled side-source geometrical configuration is proposed for obtaining a high detection sensitivity for rare earth elements (57 ≤ Z ≤ 69) by radioisotope-excited energy-dispersive x-ray fluorescence spectrometry. In this configuration a disc source of 241 Am (100 mCi), a high-purity germanium detector and thin samples of rare earth elements on a Mylar backing are employed in an optimized geometry to achieve detection limits in the range 20-50 ng for these elements in a counting time of 1 h. (author)

Determination by gamma-ray spectrometry of the plutonium and americium content of the Pu/Am separation scraps. Application to molten salts; Determination par spectrometrie gamma de la teneur en plutonium et en americium de produits issus de separation Pu/Am. Application aux bains de sels

Energy Technology Data Exchange (ETDEWEB)

Godot, A. [CEA Valduc, Dept. de Traitement des Materiaux Nucleaires, 21 - Is-sur-Tille (France); Perot, B. [CEA Cadarache, Dept. de Technologie Nucleaire, Service de Modelisation des Transferts et Mesures Nucleaires, 13 - Saint-Paul-lez-Durance (France)

2005-07-01

Within the framework of plutonium recycling operations in CEA Valduc (France), americium is extracted from molten plutonium metal into a molten salt during an electrolysis process. The scraps (spent salt, cathode, and crucible) contain extracted americium and a part of plutonium. Nuclear material management requires a very accurate determination of the plutonium content. Gamma-ray spectroscopy is performed on Molten Salt Extraction (MSE) scraps located inside the glove box, in order to assess the plutonium and americium contents. The measurement accuracy is influenced by the device geometry, nuclear instrumentation, screens located between the sample and the detector, counting statistics and matrix attenuation, self-absorption within the spent salt being very important. The purpose of this study is to validate the 'infinite energy extrapolation' method employed to correct for self-attenuation, and to detect any potential bias. We present a numerical study performed with the MCNP computer code to identify the most influential parameters and some suggestions to improve the measurement accuracy. A final uncertainty of approximately 40% is achieved on the plutonium mass. (authors)

A new method for the determination of plutonium and americium using high pressure microwave digestion and alpha-spectrometry or ICP-SMS

International Nuclear Information System (INIS)

Luisier, F.; Corcho Alvarado, J.A.; Froidevaux, P.; Steinmann, P.; Krachler, M.

2009-01-01

Plutonium and americium are radionuclides particularly difficult to measure in environmental samples because they are a-emitters and therefore necessitate a careful separation before any measurement, either using radiometric methods or ICP-SMS. Recent developments in extraction chromatography resins such as Eichrom R TRU and TEVA have resolved many of the analytical problems but drawbacks such as low recovery and spectral interferences still occasionally occur. Here, we report on the use of the new Eichrom R DGA resin in association with TEVA resin and high pressure microwave acid leaching for the sequential determination of plutonium and americium in environmental samples. The method results in average recoveries of 83 ± 15% for plutonium and 73 ± 22% for americium (n = 60), and a less than 10% deviation from reference values of four IAEA reference materials and three samples from intercomparisons exercises. The method is also suitable for measuring 239 Pu in water samples at the μBq/l level, if ICP-SMS is used for the measurement. (author)

Separation and Recycling for Rare Earth Elements by Homogeneous Liquid-Liquid Extraction (HoLLE Using a pH-Responsive Fluorine-Based Surfactant

Directory of Open Access Journals (Sweden)

Shotaro Saito

2015-08-01

Full Text Available A selective separation and recycling system for metal ions was developed by homogeneous liquid-liquid extraction (HoLLE using a fluorosurfactant. Sixty-two different elemental ions (e.g., Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, La, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Re, Rh, Ru, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tl, Tm, V, W, Y, Yb, Zn, and Zr were examined. By changing pH from a neutral or alkaline solution (pH ≥ 6.5 to that of an acidic solution (pH < 4.0, gallium, zirconium, palladium, silver, platinum, and rare earth elements were extracted at >90% efficiency into a sedimented Zonyl FSA® (CF3(CF2n(CH22S(CH22COOH, n = 6–8 liquid phase. Moreover, all rare earth elements were obtained with superior extraction and stripping percentages. In the recycling of rare earth elements, the sedimented phase was maintained using a filter along with a mixed solution of THF and 1 M sodium hydroxide aqueous solution. The Zonyl FSA® was filtrated and the rare earth elements were recovered on the filter as a hydroxide. Furthermore, the filtrated Zonyl FSA was reusable by conditioning the subject pH.

Implications of plutonium and americium recycling on MOX fuel fabrication

International Nuclear Information System (INIS)

Renard, A.; Pilate, S.; Maldague, Th.; La Fuente, A.; Evrard, G.

1995-01-01

The impact of the multiple recycling of plutonium in power reactors on the radiation dose rates is analyzed for the most critical stage in a MOX fuel fabrication plant. The limitation of the number of Pu recycling in light water reactors would rather stem from reactor core physics features. The case of recovering americium with plutonium is also considered and the necessary additions of shielding are evaluated. A comparison between the recycling of Pu in fast reactors and in light water reactors is presented. (author)

Reaction cross section calculation of some alkaline earth elements

Directory of Open Access Journals (Sweden)

Tel Eyyup

2017-01-01

Full Text Available 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.

Nuclear fission and the transuranium elements

International Nuclear Information System (INIS)

Seaborg, G.T.

1989-02-01

Many of the transuranium elements are produced and isolated in large quantities through the use of neutrons furnished by nuclear fission reactions: plutonium (atomic number 94) in ton quantities; neptunium (93), americium (95), and curium (96) in kilogram quantities; berkelium (97) in 100 milligram quantities; californium (98) in gram quantities; and einsteinium (99) in milligram quantities. Transuranium isotopes have found many practical applications---as nuclear fuel for the large-scale generation of electricity, as compact, long-lived power sources for use in space exploration, as means for diagnosis and treatment in the medical area, and as tools in numerous industrial processes. Of particular interest is the unusual chemistry and impact of these heaviest elements on the periodic table. This account will feature these aspects. 9 refs., 5 figs

Nuclear fission and the transuranium elements

Energy Technology Data Exchange (ETDEWEB)

Seaborg, G.T.

1989-02-01

Many of the transuranium elements are produced and isolated in large quantities through the use of neutrons furnished by nuclear fission reactions: plutonium (atomic number 94) in ton quantities; neptunium (93), americium (95), and curium (96) in kilogram quantities; berkelium (97) in 100 milligram quantities; californium (98) in gram quantities; and einsteinium (99) in milligram quantities. Transuranium isotopes have found many practical applications---as nuclear fuel for the large-scale generation of electricity, as compact, long-lived power sources for use in space exploration, as means for diagnosis and treatment in the medical area, and as tools in numerous industrial processes. Of particular interest is the unusual chemistry and impact of these heaviest elements on the periodic table. This account will feature these aspects. 9 refs., 5 figs.

Chemical behaviour of trivalent and pentavalent americium in saline NaCl-solutions. Studies of transferability of laboratory data to natural conditions. Interim report. Reported period: 1.2.1993-31.12.1993; Chemisches Verhalten von drei- und fuenfwertigem Americium in Salinen NaCl-Loesungen. Untersuchung der Uebertragbarkeit von Labordaten auf natuerliche Verhaeltnisse. Zwischenbericht. Berichtszeitraum 1.2.1993-31.12.1993

Energy Technology Data Exchange (ETDEWEB)

Runde, W; Kim, J I

1994-09-15

In order to clarify the chemical behaviour of Americium in saline aqueous systems relevant for final storage this study deals with the chemical reactions of trivalent and pentavalent Americium in NaCl-solutions under the influence of radiolysis from its own alpha radiation. The focus of the study was on investigating the geologically relevant reactions, such as hydrolysis or carbonate- and chloride complexing in solid-liquid equilibriums. Comprehensive measurements on solubility and spectroscopic studies in NaCl-solutions were carried out in a CO{sub 2}-free atmosphere and 10{sup -2} atm CO{sub 2} partial pressure. Identification and characterisation of the AM (III) and AM(V) solid phases were supplemented by structural research with the chemically analogue EU (III) and Np(V) compounds. The alpha-radiation induced radiolysis in saline NaCl solutions and the redox behaviour of Americium which was influenced thereby were spectroscopically quantified. (orig.) [Deutsch] Zur Klaerung des chemischen Verhaltens von Americium in endlagerrelevanten salinen aquatischen Systemen befasst sich die vorliegende Arbeit mit den chemischen Reaktionen des drei- und fuenfwertigen Americiums in NaCl-Loesungen unter dem Einfluss der Radiolyse durch die eigene {alpha}-Strahlung. Der Schwerpunkt dieser Arbeit lag auf der Untersuchung der geologisch relevanten Reaktionen, wie Hydrolyse sowie Carbonat- und Chloridkomplexierung in fest-fluessig Gleichgewichtssystemen. Hierzu wurden umfassende Loeslichkeitsmessungen und spektroskopische Untersuchungen in NaCl-Loesungen, sowohl unter CO{sub 2}-freier Atmosphaere als auch unter 10{sup -2} atm CO{sub 2}-Partialdruck, durchgefuehrt. Die Identifizierung und Charakterisierung der Am(III)- und Am(V)-Festphasen wurde ergaenzt durch strukturelle Untersuchungen mit den chemisch analogen Eu(III)- und Np(V)-Verbindungen. Die von der {alpha}-Strahlung induzierte Radiolyse in salinen NaCl-Loesungen und das dadurch beeinflusste Redoxverhalten von Americium

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.

Americium/Curium Vitrification Pilot Tests - Part II