Sample records for alkali metal molten

  1. Electrochemical cell utilizing molten alkali metal electrode-reactant

    DOEpatents

    Virkar, Anil V.; Miller, Gerald R.

    1983-11-04

    An improved electrochemical cell comprising an additive-modified molten alkali metal electrode-reactant and/or electrolyte is disclosed. Various electrochemical cells employing a molten alkali metal, e.g., sodium, electrode in contact with a cationically conductive ceramic membrane experience a lower resistance and a lower temperature coefficient of resistance whenever small amounts of selenium are present at the interface of the electrolyte and the molten alkali metal. Further, cells having small amounts of selenium present at the electrolyte-molten metal interface exhibit less degradation of the electrolyte under long term cycling conditions.

  2. Spectroscopic studies of transition-metal ions in molten alkali-metal carboxylates

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maroni, V.A.; Maciejewski, M.L.

    This paper presents the results of electronic absorption and /sup 13/C-NMR measurements on molten alkali metal formates and acetates and on solutions of selected 3d transition metal ions therein. These studies provide a unique opportunity to explore (1) the highly ordered nature of alkali carboxylates, (2) the ligand field properties of acetate and formate ions, and (3) the coordination chemistry of the 3d transition metals in molten carboxylates. 1 figure, 2 tables.

  3. Electrochemical devices utilizing molten alkali metal electrode-reactant

    DOEpatents

    Hitchcock, David C.; Mailhe, Catherine C.; De Jonghe, Lutgard C.

    1986-01-01

    Electrochemical cells are provided with a reactive metal to reduce the oxide of the alkali metal electrode-reactant. Cells employing a molten alkali metal electrode, e.g., sodium, in contact with a ceramic electrolyte, which is a conductor of the ions of the alkali metal forming the electrode, exhibit a lower resistance when a reactive metal, e.g., vanadium, is allowed to react with and reduce the alkali metal oxide. Such cells exhibit less degradation of the electrolyte and of the glass seals often used to joining the electrolyte to the other components of the cell under cycling conditions.

  4. Electrochemical devices utilizing molten alkali metal electrode-reactant

    DOEpatents

    Hitchcock, D.C.; Mailhe, C.C.; De Jonghe, L.C.

    1985-07-10

    Electrochemical cells are provided with a reactive metal to reduce the oxide of the alkali metal electrode-reactant. Cells employing a molten alkali metal electrode, e.g., sodium, in contact with a ceramic electrolyte, which is a conductor of the ions of the alkali metal forming the electrode, exhibit a lower resistance when a reactive metal, e.g., vanadium, is allowed to react with and reduce the alkali metal oxide. Such cells exhibit less degradation of the electrolyte and of the glass seals often used to joining the electrolyte to the other components of the cell under cycling conditions.

  5. Alkali metal nitrate purification

    DOEpatents

    Fiorucci, Louis C.; Morgan, Michael J.

    1986-02-04

    A process is disclosed for removing contaminants from impure alkali metal nitrates containing them. The process comprises heating the impure alkali metal nitrates in solution form or molten form at a temperature and for a time sufficient to effect precipitation of solid impurities and separating the solid impurities from the resulting purified alkali metal nitrates. The resulting purified alkali metal nitrates in solution form may be heated to evaporate water therefrom to produce purified molten alkali metal nitrates suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of purified alkali metal nitrates.

  6. Alkali metal ion battery with bimetallic electrode

    DOEpatents

    Boysen, Dane A; Bradwell, David J; Jiang, Kai; Kim, Hojong; Ortiz, Luis A; Sadoway, Donald R; Tomaszowska, Alina A; Wei, Weifeng; Wang, Kangli

    2015-04-07

    Electrochemical cells having molten electrodes having an alkali metal provide receipt and delivery of power by transporting atoms of the alkali metal between electrode environments of disparate chemical potentials through an electrochemical pathway comprising a salt of the alkali metal. The chemical potential of the alkali metal is decreased when combined with one or more non-alkali metals, thus producing a voltage between an electrode comprising the molten the alkali metal and the electrode comprising the combined alkali/non-alkali metals.

  7. Purification of alkali metal nitrates

    DOEpatents

    Fiorucci, Louis C.; Gregory, Kevin M.

    1985-05-14

    A process is disclosed for removing heavy metal contaminants from impure alkali metal nitrates containing them. The process comprises mixing the impure nitrates with sufficient water to form a concentrated aqueous solution of the impure nitrates, adjusting the pH of the resulting solution to within the range of between about 2 and about 7, adding sufficient reducing agent to react with heavy metal contaminants within said solution, adjusting the pH of the solution containing reducing agent to effect precipitation of heavy metal impurities and separating the solid impurities from the resulting purified aqueous solution of alkali metal nitrates. The resulting purified solution of alkali metal nitrates may be heated to evaporate water therefrom to produce purified molten alkali metal nitrate suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of alkali metal nitrates.

  8. Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

    DOEpatents

    Cassano, Anthony A.

    1985-01-01

    A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs.

  9. Method for the safe disposal of alkali metal

    DOEpatents

    Johnson, Terry R.

    1977-01-01

    Alkali metals such as those employed in liquid metal coolant systems can be safely reacted to form hydroxides by first dissolving the alkali metal in relatively inert metals such as lead or bismuth. The alloy thus formed is contacted with a molten salt including the alkali metal hydroxide and possibly the alkali metal carbonate in the presence of oxygen. This oxidizes the alkali metal to an oxide which is soluble within the molten salt. The salt is separated and contacted with steam or steam-CO.sub.2 mixture to convert the alkali metal oxide to the hydroxide. These reactions can be conducted with minimal hydrogen evolution and with the heat of reaction distributed between the several reaction steps.

  10. Electrochemical cell having an alkali-metal-nitrate electrode

    DOEpatents

    Roche, M.F.; Preto, S.K.

    1982-06-04

    A power-producing secondary electrochemical cell includes a molten alkali metal as the negative-electrode material and a molten-nitrate salt as the positive-electrode material. The molten material in the respective electrodes are separated by a solid barrier of alkali-metal-ion conducting material. A typical cell includes active materials of molten sodium separated from molten sodium nitrate and other nitrates in mixture by a layer of sodium ..beta..'' alumina.

  11. Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

    DOEpatents

    Cassano, A.A.

    1985-07-02

    A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs. 3 figs.

  12. Study of the reaction of tungsten carbide in molten alkali metal nitrates. Syntheses of divalent (s and d blocks) metal tungstates

    NASA Astrophysics Data System (ADS)

    Deloume, Jean-Pierre; Marote, Pedro; Sigala, Catherine; Matei, Cristian

    2003-08-01

    WC is tested as precursor to synthesize metal tungstates by reaction in molten alkali metal nitrates. This constitutes a complex redox system with two reducing agents, W and C, and an oxidizer having several oxidation states. The mass loss due to the evolution of gases reveals the reaction steps. The infrared analyses of the gas phase show what kind of reaction develops according to the temperature. WC produces a water-soluble alkali metal tungstate. The reaction of a mixture of WC and a divalent metal chloride (Mg, Ca, Ba, Ni, Cu, Zn) leads to water-insoluble metal tungstates. As the reactivity of the cations increases in the order Zn, Ni, Cu, the reaction of WC is modified by their presence. The physico-chemical characterizations of the products show that some of them are contaminated either by WC or by metal oxide. Some others are rather pure products. These differences, in relationship with the other analyses, allow to propose first reaction pathways of the tungsten carbide in molten salts.

  13. Method for inhibiting alkali metal corrosion of nickel-containing alloys

    DOEpatents

    DeVan, Jackson H.; Selle, James E.

    1983-01-01

    Structural components of nickel-containing alloys within molten alkali metal systems are protected against corrosion during the course of service by dissolving therein sufficient aluminum, silicon, or manganese to cause the formation and maintenance of a corrosion-resistant intermetallic reaction layer created by the interaction of the molten metal, selected metal, and alloy.

  14. Cation and anion dependence of stable geometries and stabilization energies of alkali metal cation complexes with FSA(-), FTA(-), and TFSA(-) anions: relationship with physicochemical properties of molten salts.

    PubMed

    Tsuzuki, Seiji; Kubota, Keigo; Matsumoto, Hajime

    2013-12-19

    Stable geometries and stabilization energies (Eform) of the alkali metal complexes with bis(fluorosulfonyl)amide, (fluorosulfonyl)(trifluoromethylslufonyl)amide and bis(trifluoromethylsulfonyl)amide (FSA(-), FTA(-) and TFSA(-)) were studied by ab initio molecular orbital calculations. The FSA(-) complexes prefer the bidentate structures in which two oxygen atoms of two SO2 groups have contact with the metal cation. The FTA(-) and TFSA(-) complexes with Li(+) and Na(+) prefer the bidentate structures, while the FTA(-) and TFSA(-) complexes with Cs(+) prefer tridentate structures in which the metal cation has contact with two oxygen atoms of an SO2 group and one oxygen atom of another SO2 group. The two structures are nearly isoenergetic in the FTA(-) and TFSA(-) complexes with K(+) and Rb(+). The magnitude of Eform depends on the alkali metal cation significantly. The Eform calculated for the most stable TFSA(-) complexes with Li(+), Na(+), K(+), Rb(+) and Cs(+) cations at the MP2/6-311G** level are -137.2, -110.5, -101.1, -89.6, and -84.1 kcal/mol, respectively. The viscosity and ionic conductivity of the alkali TFSA molten salts have strong correlation with the magnitude of the attraction. The viscosity increases and the ionic conductivity decreases with the increase of the attraction. The melting points of the alkali TFSA and alkali BETA molten salts also have correlation with the magnitude of the Eform, which strongly suggests that the magnitude of the attraction play important roles in determining the melting points of these molten salts. The anion dependence of the Eform calculated for the complexes is small (less than 2.9 kcal/mol). This shows that the magnitude of the attraction is not the cause of the low melting points of alkali FTA molten salts compared with those of corresponding alkali TFSA molten salts. The electrostatic interactions are the major source of the attraction in the complexes. The electrostatic energies for the most stable TFSA

  15. Spill-Resistant Alkali-Metal-Vapor Dispenser

    NASA Technical Reports Server (NTRS)

    Klipstein, William

    2005-01-01

    A spill-resistant vessel has been developed for dispensing an alkali-metal vapor. Vapors of alkali metals (most commonly, cesium or rubidium, both of which melt at temperatures slightly above room temperature) are needed for atomic frequency standards, experiments in spectroscopy, and experiments in laser cooling. Although the present spill-resistant alkali-metal dispenser was originally intended for use in the low-gravity environment of outer space, it can also be used in normal Earth gravitation: indeed, its utility as a vapor source was confirmed by use of cesium in a ground apparatus. The vessel is made of copper. It consists of an assembly of cylinders and flanges, shown in the figure. The uppermost cylinder is a fill tube. Initially, the vessel is evacuated, the alkali metal charge is distilled into the bottom of the vessel, and then the fill tube is pinched closed to form a vacuum seal. The innermost cylinder serves as the outlet for the vapor, yet prevents spilling by protruding above the surface of the alkali metal, no matter which way or how far the vessel is tilted. In the event (unlikely in normal Earth gravitation) that any drops of molten alkali metal have been shaken loose by vibration and are floating freely, a mesh cap on top of the inner cylinder prevents the drops from drifting out with the vapor. Liquid containment of the equivalent of 1.2 grams of cesium was confirmed for all orientations with rubbing alcohol in one of the prototypes later used with cesium.

  16. Alkali metal/sulfur battery

    DOEpatents

    Anand, Joginder N.

    1978-01-01

    Alkali metal/sulfur batteries in which the electrolyte-separator is a relatively fragile membrane are improved by providing means for separating the molten sulfur/sulfide catholyte from contact with the membrane prior to cooling the cell to temperatures at which the catholyte will solidify. If the catholyte is permitted to solidify while in contact with the membrane, the latter may be damaged. The improvement permits such batteries to be prefilled with catholyte and shipped, at ordinary temperatures.

  17. Alkali metal protective garment and composite material

    DOEpatents

    Ballif, III, John L.; Yuan, Wei W.

    1980-01-01

    A protective garment and composite material providing satisfactory heat resistance and physical protection for articles and personnel exposed to hot molten alkali metals, such as sodium. Physical protection is provided by a continuous layer of nickel foil. Heat resistance is provided by an underlying backing layer of thermal insulation. Overlying outer layers of fireproof woven ceramic fibers are used to protect the foil during storage and handling.

  18. Process to separate alkali metal salts from alkali metal reacted hydrocarbons

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gordon, John Howard; Alvare, Javier; Larsen, Dennis

    A process to facilitate gravimetric separation of alkali metal salts, such as alkali metal sulfides and polysulfides, from alkali metal reacted hydrocarbons. The disclosed process is part of a method of upgrading a hydrocarbon feedstock by removing heteroatoms and/or one or more heavy metals from the hydrocarbon feedstock composition. This method reacts the oil feedstock with an alkali metal and an upgradant hydrocarbon. The alkali metal reacts with a portion of the heteroatoms and/or one or more heavy metals to form an inorganic phase containing alkali metal salts and reduced heavy metals, and an upgraded hydrocarbon feedstock. The inorganic phasemore » may be gravimetrically separated from the upgraded hydrocarbon feedstock after mixing at a temperature between about 350.degree. C. to 400.degree. C. for a time period between about 15 minutes and 2 hours.« less

  19. Extraction process for removing metallic impurities from alkalide metals

    DOEpatents

    Royer, L.T.

    1987-03-20

    A development is described for removing metallic impurities from alkali metals by employing an extraction process wherein the metallic impurities are extracted from a molten alkali metal into molten lithium metal due to the immiscibility of the alkali metals in lithium and the miscibility of the metallic contaminants or impurities in the lithium. The purified alkali metal may be readily separated from the contaminant-containing lithium metal by simple decanting due to the differences in densities and melting temperatures of the alkali metals as compared to lithium.

  20. A rechargeable lithium metal battery operating at intermediate temperatures using molten alkali bis(trifluoromethylsulfonyl)amide mixture as an electrolyte

    NASA Astrophysics Data System (ADS)

    Watarai, Atsushi; Kubota, Keigo; Yamagata, Masaki; Goto, Takuya; Nohira, Toshiyuki; Hagiwara, Rika; Ui, Koichi; Kumagai, Naoaki

    The physicochemical properties of molten alkali bis(trifluoromethylsulfonyl)amide, MTFSI (M = Li, K, Cs), mixture (x LiTFSI = 0.20, x KTFSI = 0.10, x CsTFSI = 0.70) were studied to develop a new rechargeable lithium battery operating at intermediate temperature (100-180 °C). The viscosity and ionic conductivity of this melt at 150 °C are 87.2 cP and 14.2 mS cm -1, respectively. The cyclic voltammetry revealed that the electrochemical window at 150 °C is as wide as 5.0 V, and that the electrochemical deposition/dissolution of lithium metal occurs at the cathode limit. A Li/MTFSI (M = Li, K, Cs)/LiFePO 4 cell showed an excellent cycle performance at a constant current rate of C/10 at 150 °C; 95% of the initial discharge capacity was maintained after 50 cycles. Except for the initial few cycles, the coulombic efficiencies were approximately 100% for all the cycles, indicating the stabilities of the molten MTFSI mixture and all the electrode materials.

  1. Molten metal injector system and method

    DOEpatents

    Meyer, Thomas N.; Kinosz, Michael J.; Bigler, Nicolas; Arnaud, Guy

    2003-04-01

    Disclosed is a molten metal injector system including a holder furnace, a casting mold supported above the holder furnace, and a molten metal injector supported from a bottom side of the mold. The holder furnace contains a supply of molten metal having a metal oxide film surface. The bottom side of the mold faces the holder furnace. The mold defines a mold cavity for receiving the molten metal from the holder furnace. The injector projects into the holder furnace and is in fluid communication with the mold cavity. The injector includes a piston positioned within a piston cavity defined by a cylinder for pumping the molten metal upward from the holder furnace and injecting the molten metal into the mold cavity under pressure. The piston and cylinder are at least partially submerged in the molten metal when the holder furnace contains the molten metal. The cylinder further includes a molten metal intake for receiving the molten metal into the piston cavity. The molten metal intake is located below the metal oxide film surface of the molten metal when the holder furnace contains the molten metal. A method of injecting molten metal into a mold cavity of a casting mold is also disclosed.

  2. The use of molten salts as physical models for the study of solidification in metals and semiconductors

    NASA Technical Reports Server (NTRS)

    Koziol, Jurek K.; Sadoway, Donald R.

    1987-01-01

    It is presently noted that molten salts possess attributes rendering them attractive as physical models of cast metals in solidification studies. Molten alkali halides have an approximately correct Prandtl number for this modeling of metallic melts, and are transparent to visible light. Attention is given to solidification in the LiCl-KCl system, in order to determine whether such phenomena as solute rejection can be observed and characterized through the application of laser schlieren imaging.

  3. Hydrothermal alkali metal recovery process

    DOEpatents

    Wolfs, Denise Y.; Clavenna, Le Roy R.; Eakman, James M.; Kalina, Theodore

    1980-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by treating them with a calcium or magnesium-containing compound in the presence of water at a temperature between about 250.degree. F. and about 700.degree. F. and in the presence of an added base to establish a pH during the treatment step that is higher than would otherwise be possible without the addition of the base. During the treating process the relatively high pH facilitates the conversion of water-insoluble alkali metal compounds in the alkali metal residues into water-soluble alkali metal constituents. The resultant aqueous solution containing water-soluble alkali metal constituents is then separated from the residue solids, which consist of the treated particles and any insoluble materials formed during the treatment step, and recycled to the gasification process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst. Preferably, the base that is added during the treatment step is an alkali metal hydroxide obtained by water washing the residue solids produced during the treatment step.

  4. EXTINGUISHMENT OF ALKALI METAL FIRES

    DTIC Science & Technology

    low O2 partial pressures on alkali metal fires Extinguishment of alkali metal fires using in organic salt mixtures Extinguishment of alkali metal ... fires using inorganic salt foams Alkali metal jet stream ignition at various pressure conditions Bibliography

  5. Integrated oil production and upgrading using molten alkali metal

    DOEpatents

    Gordon, John Howard

    2016-10-04

    A method that combines the oil retorting process (or other process needed to obtain/extract heavy oil or bitumen) with the process for upgrading these materials using sodium or other alkali metals. Specifically, the shale gas or other gases that are obtained from the retorting/extraction process may be introduced into the upgrading reactor and used to upgrade the oil feedstock. Also, the solid materials obtained from the reactor may be used as a fuel source, thereby providing the heat necessary for the retorting/extraction process. Other forms of integration are also disclosed.

  6. Hydrothermal alkali metal catalyst recovery process

    DOEpatents

    Eakman, James M.; Clavenna, LeRoy R.

    1979-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles primarily in the form of water soluble alkali metal formates by treating the particles with a calcium or magnesium-containing compound in the presence of water at a temperature between about 250.degree. F. and about 700.degree. F. and in the presence of added carbon monoxide. During the treating process the water insoluble alkali metal compounds comprising the insoluble alkali metal residues are converted into water soluble alkali metal formates. The resultant aqueous solution containing water soluble alkali metal formates is then separated from the treated particles and any insoluble materials formed during the treatment process, and recycled to the gasification process where the alkali metal formates serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst. This process permits increased recovery of alkali metal constituents, thereby decreasing the overall cost of the gasification process by reducing the amount of makeup alkali metal compounds necessary.

  7. Alkali metal and alkali earth metal gadolinium halide scintillators

    DOEpatents

    Bourret-Courchesne, Edith; Derenzo, Stephen E.; Parms, Shameka; Porter-Chapman, Yetta D.; Wiggins, Latoria K.

    2016-08-02

    The present invention provides for a composition comprising an inorganic scintillator comprising a gadolinium halide, optionally cerium-doped, having the formula A.sub.nGdX.sub.m:Ce; wherein A is nothing, an alkali metal, such as Li or Na, or an alkali earth metal, such as Ba; X is F, Br, Cl, or I; n is an integer from 1 to 2; m is an integer from 4 to 7; and the molar percent of cerium is 0% to 100%. The gadolinium halides or alkali earth metal gadolinium halides are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

  8. Methods of recovering alkali metals

    DOEpatents

    Krumhansl, James L; Rigali, Mark J

    2014-03-04

    Approaches for alkali metal extraction, sequestration and recovery are described. For example, a method of recovering alkali metals includes providing a CST or CST-like (e.g., small pore zeolite) material. The alkali metal species is scavenged from the liquid mixture by the CST or CST-like material. The alkali metal species is extracted from the CST or CST-like material.

  9. EXTINGUISHMENT OF ALKALI METAL FIRES

    DTIC Science & Technology

    Contents: Effect of inert gas nket and ow O2 partial pressures on alkali metal fires Extinguishment of small scale fires Extinguishment of alkali... metal fires using inorganic salt foam Alkali metal jet stream ignition at various pressure conditions

  10. Alkali metal for ultraviolet band-pass filter

    NASA Technical Reports Server (NTRS)

    Mardesich, Nick (Inventor); Fraschetti, George A. (Inventor); Mccann, Timothy A. (Inventor); Mayall, Sherwood D. (Inventor); Dunn, Donald E. (Inventor); Trauger, John T. (Inventor)

    1993-01-01

    An alkali metal filter having a layer of metallic bismuth deposited onto the alkali metal is provided. The metallic bismuth acts to stabilize the surface of the alkali metal to prevent substantial surface migration from occurring on the alkali metal, which may degrade optical characteristics of the filter. To this end, a layer of metallic bismuth is deposited by vapor deposition over the alkali metal to a depth of approximately 5 to 10 A. A complete alkali metal filter is described along with a method for fabricating the alkali metal filter.

  11. Molten metal holder furnace and casting system incorporating the molten metal holder furnace

    DOEpatents

    Kinosz, Michael J.; Meyer, Thomas N.

    2003-02-11

    A bottom heated holder furnace (12) for containing a supply of molten metal includes a storage vessel (30) having sidewalls (32) and a bottom wall (34) defining a molten metal receiving chamber (36). A furnace insulating layer (42) lines the molten metal receiving chamber (36). A thermally conductive heat exchanger block (54) is located at the bottom of the molten metal receiving chamber (36) for heating the supply of molten metal. The heat exchanger block (54) includes a bottom face (65), side faces (66), and a top face (67). The heat exchanger block (54) includes a plurality of electrical heaters (70) extending therein and projecting outward from at least one of the faces of the heat exchanger block (54), and further extending through the furnace insulating layer (42) and one of the sidewalls (32) of the storage vessel (30) for connection to a source of electrical power. A sealing layer (50) covers the bottom face (65) and side faces (66) of the heat exchanger block (54) such that the heat exchanger block (54) is substantially separated from contact with the furnace insulating layer (42).

  12. EXTINGUISHMENT OF ALKALI METAL FIRES

    DTIC Science & Technology

    was found to be effective on low temperature (1000F) fires and was useful on alkali metal fires on or under insulation. Organic liquids were not...particularly effective on alkali metal fires . A section is presented on a typical alkali metal system which might be used to generate electrical power in space.

  13. Borohydride electro-oxidation in a molten alkali hydroxide eutectic mixture and a novel borohydride-periodate battery

    NASA Astrophysics Data System (ADS)

    Wang, Andrew; Gyenge, Előd L.

    2015-05-01

    The electrochemical oxidation of BH4- in a molten NaOH-KOH eutectic mixture (0.515:0.485 mole fractions), is investigated for the first time by cyclic voltammetry and electrochemical impedance spectroscopy. Anodically oxidized Ni is electrocatalytically more active than Pt for BH4- oxidation in the molten alkali electrolyte as shown by the more than three times higher exchange current density (i.e. 15.8 mA cm-2 vs. 4.6 mA cm-2 at 185 °C). Next the proof-of-concept for a novel BH4-/IO4- molten alkali electrolyte battery is presented. Using oxidized Ni mesh anode and Pt mesh cathode a maximum power density of 63 mW cm-2 is achieved at 185 °C.

  14. Supported molten-metal catalysts

    DOEpatents

    Datta, Ravindra; Singh, Ajeet; Halasz, Istvan; Serban, Manuela

    2001-01-01

    An entirely new class of catalysts called supported molten-metal catalysts, SMMC, which can replace some of the existing precious metal catalysts used in the production of fuels, commodity chemicals, and fine chemicals, as well as in combating pollution. SMMC are based on supporting ultra-thin films or micro-droplets of the relatively low-melting (<600.degree. C.), inexpensive, and abundant metals and semimetals from groups 1, 12, 13, 14, 15 and 16, of the periodic table, or their alloys and intermetallic compounds, on porous refractory supports, much like supported microcrystallites of the traditional solid metal catalysts. It thus provides orders of magnitude higher surface area than is obtainable in conventional reactors containing molten metals in pool form and also avoids corrosion. These have so far been the chief stumbling blocks in the application of molten metal catalysts.

  15. Alkali metal ionization detector

    DOEpatents

    Bauerle, James E.; Reed, William H.; Berkey, Edgar

    1978-01-01

    Variations in the conventional filament and collector electrodes of an alkali metal ionization detector, including the substitution of helical electrode configurations for either the conventional wire filament or flat plate collector; or, the substitution of a plurality of discrete filament electrodes providing an in situ capability for transferring from an operationally defective filament electrode to a previously unused filament electrode without removing the alkali metal ionization detector from the monitored environment. In particular, the helical collector arrangement which is coaxially disposed about the filament electrode, i.e. the thermal ionizer, provides an improved collection of positive ions developed by the filament electrode. The helical filament design, on the other hand, provides the advantage of an increased surface area for ionization of alkali metal-bearing species in a monitored gas environment as well as providing a relatively strong electric field for collecting the ions at the collector electrode about which the helical filament electrode is coaxially positioned. Alternatively, both the filament and collector electrodes can be helical. Furthermore, the operation of the conventional alkali metal ionization detector as a leak detector can be simplified as to cost and complexity, by operating the detector at a reduced collector potential while maintaining the sensitivity of the alkali metal ionization detector adequate for the relatively low concentration of alkali vapor and aerosol typically encountered in leak detection applications.

  16. Alkali metal hafnium oxide scintillators

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bourret-Courchesne, Edith; Derenzo, Stephen E.; Taylor, Scott Edward

    The present invention provides for a composition comprising an inorganic scintillator comprising an alkali metal hafnate, optionally cerium-doped, having the formula A 2HfO 3:Ce; wherein A is an alkali metal having a valence of 1, such as Li or Na; and the molar percent of cerium is 0% to 100%. The alkali metal hafnate are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

  17. Alkali metal recovery from carbonaceous material conversion process

    DOEpatents

    Sharp, David W.; Clavenna, LeRoy R.; Gorbaty, Martin L.; Tsou, Joe M.

    1980-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced in the gasifier or similar reaction zone, alkali metal constitutents are recovered from the particles by withdrawing and passing the particles from the reaction zone to an alkali metal recovery zone in the substantial absence of molecular oxygen and treating the particles in the recovery zone with water or an aqueous solution in the substantial absence of molecular oxygen. The solution formed by treating the particles in the recovery zone will contain water-soluble alkali metal constituents and is recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst. Preventing contact of the particles with oxygen as they are withdrawn from the reaction zone and during treatment in the recovery zone avoids the formation of undesirable alkali metal constituents in the aqueous solution produced in the recovery zone and insures maximum recovery of water-soluble alkali metal constituents from the alkali metal residues.

  18. Metal Oxide Solubility and Molten Salt Corrosion.

    DTIC Science & Technology

    1982-03-29

    METAL OXIDE SOLUBILITY AND MOLTEN SALT CORROSION .(U) MAR 82 K H STERN UNCLASSI E DL R L-4772NL EL .2. MICROCOPY RESOLUTION TEST CHART NATIONAL BURALU...21 l 7 3 ..... l DTIC NSPECT I" ’I cCPY INSECE( METAL OXIDE SOLUBILITY AND MOLTEN SALT CORROSION I. INTRODUCTION Molten ...discussed in terms of its importance to the understanding of molten salt corrosion . II. PROTECTIVE COATINGS Since most structural metals and alloys are

  19. Structural evolution of fluorinated graphene upon molten-alkali treatment probed by X-ray absorption near-edge structure spectroscopy

    NASA Astrophysics Data System (ADS)

    Liang, Xianqing; Pan, Deyou; Lao, Ming; Liang, Shuiying; Huang, Dan; Zhou, Wenzheng; Guo, Jin

    2017-05-01

    The structural evolution of fluorinated graphene (FG) nanosheets upon molten-alkali treatment has been systematically investigated utilizing X-ray absorption near-edge structure (XANES) spectroscopy. It is found that the hydroxyl groups can progressively displace fluorine atoms to form covalent bonds to the graphene sheets under designed molten-alkali condition. The XANES spectra also reveal the formation of epoxide groups through intramolecular dehydration of neighbouring hydroxyl groups after substitution reaction. At high alkali-FG weight ratio, the restoration of the π-conjugated structure in graphene sheets can be observed due to the gradual decomposition of epoxide groups. Our experimental results indicate that the surface chemistry and electronic structure of hydroxyl-functionalized FG (HFG) can be readily tuned by varying the ratio of reactants.

  20. Apparatus enables accurate determination of alkali oxides in alkali metals

    NASA Technical Reports Server (NTRS)

    Dupraw, W. A.; Gahn, R. F.; Graab, J. W.; Maple, W. E.; Rosenblum, L.

    1966-01-01

    Evacuated apparatus determines the alkali oxide content of an alkali metal by separating the metal from the oxide by amalgamation with mercury. The apparatus prevents oxygen and moisture from inadvertently entering the system during the sampling and analytical procedure.

  1. PROCESS OF RECOVERING ALKALI METALS

    DOEpatents

    Wolkoff, J.

    1961-08-15

    A process is described of recovering alkali metal vapor by sorption on activated alumina, activated carbon, dehydrated zeolite, activated magnesia, or Fuller's earth preheated above the vaporization temperature of the alkali metal and subsequent desorption by heating the solvent under vacuum. (AEC)

  2. Method of handling radioactive alkali metal waste

    DOEpatents

    Wolson, Raymond D.; McPheeters, Charles C.

    1980-01-01

    Radioactive alkali metal is mixed with particulate silica in a rotary drum reactor in which the alkali metal is converted to the monoxide during rotation of the reactor to produce particulate silica coated with the alkali metal monoxide suitable as a feed material to make a glass for storing radioactive material. Silica particles, the majority of which pass through a 95 mesh screen or preferably through a 200 mesh screen, are employed in this process, and the preferred weight ratio of silica to alkali metal is 7 to 1 in order to produce a feed material for the final glass product having a silica to alkali metal monoxide ratio of about 5 to 1.

  3. Method of handling radioactive alkali metal waste

    DOEpatents

    Wolson, R.D.; McPheeters, C.C.

    Radioactive alkali metal is mixed with particulate silica in a rotary drum reactor in which the alkali metal is converted to the monoxide during rotation of the reactor to produce particulate silica coated with the alkali metal monoxide suitable as a feed material to make a glass for storing radioactive material. Silica particles, the majority of which pass through a 95 mesh screen or preferably through a 200 mesh screen, are employed in this process, and the preferred weight ratio of silica to alkali metal is 7 to 1 in order to produce a feed material for the final glass product having a silica to alkali metal monoxide ratio of about 5 to 1.

  4. Casting Apparatus Including A Gas Driven Molten Metal Injector And Method

    DOEpatents

    Trudel, David R.; Meyer, Thomas N.; Kinosz, Michael J.; Arnaud, Guy; Bigler, Nicolas

    2003-06-17

    The filtering molten metal injector system includes a holder furnace, a casting mold supported above the holder furnace, and at least one molten metal injector supported from a bottom side of the casting mold. The holder furnace contains a supply of molten metal. The mold defines a mold cavity for receiving the molten metal from the holder furnace. The molten metal injector projects into the holder furnace. The molten metal injector includes a cylinder defining a piston cavity housing a reciprocating piston for pumping the molten metal upward from the holder furnace to the mold cavity. The cylinder and piston are at least partially submerged in the molten metal when the holder furnace contains the molten metal. The cylinder or the piston includes a molten metal intake for receiving the molten metal into the piston cavity when the holder furnace contains molten metal. A conduit connects the piston cavity to the mold cavity. A molten metal filter is located in the conduit for filtering the molten metal passing through the conduit during the reciprocating movement of the piston. The molten metal intake may be a valve connected to the cylinder, a gap formed between the piston and an open end of the cylinder, an aperture defined in the sidewall of the cylinder, or a ball check valve incorporated into the piston. A second molten metal filter preferably covers the molten metal intake to the injector.

  5. In situ spectroscopy and spectroelectrochemistry of uranium in high-temperature alkali chloride molten salts.

    PubMed

    Polovov, Ilya B; Volkovich, Vladimir A; Charnock, John M; Kralj, Brett; Lewin, Robert G; Kinoshita, Hajime; May, Iain; Sharrad, Clint A

    2008-09-01

    Soluble uranium chloride species, in the oxidation states of III+, IV+, V+, and VI+, have been chemically generated in high-temperature alkali chloride melts. These reactions were monitored by in situ electronic absorption spectroscopy. In situ X-ray absorption spectroscopy of uranium(VI) in a molten LiCl-KCl eutectic was used to determine the immediate coordination environment about the uranium. The dominant species in the melt was [UO 2Cl 4] (2-). Further analysis of the extended X-ray absorption fine structure data and Raman spectroscopy of the melts quenched back to room temperature indicated the possibility of ordering beyond the first coordination sphere of [UO 2Cl 4] (2-). The electrolytic generation of uranium(III) in a molten LiCl-KCl eutectic was also investigated. Anodic dissolution of uranium metal was found to be more efficient at producing uranium(III) in high-temperature melts than the cathodic reduction of uranium(IV). These high-temperature electrolytic processes were studied by in situ electronic absorption spectroelectrochemistry, and we have also developed in situ X-ray absorption spectroelectrochemistry techniques to probe both the uranium oxidation state and the uranium coordination environment in these melts.

  6. Low temperature oxidation using support molten salt catalysts

    DOEpatents

    Weimer, Alan W.; Czerpak, Peter J.; Hilbert, Patrick M.

    2003-05-20

    Molten salt reactions are performed by supporting the molten salt on a particulate support and forming a fluidized bed of the supported salt particles. The method is particularly suitable for combusting hydrocarbon fuels at reduced temperatures, so that the formation NO.sub.x species is reduced. When certain preferred salts are used, such as alkali metal carbonates, sulfur and halide species can be captured by the molten salt, thereby reducing SO.sub.x and HCl emissions.

  7. Recirculating Molten Metal Supply System And Method

    DOEpatents

    Kinosz, Michael J.; Meyer, Thomas N.

    2003-07-01

    The melter furnace includes a heating chamber (16), a pump chamber (18), a degassing chamber (20), and a filter chamber (22). The pump chamber (18) is located adjacent the heating chamber (16) and houses a molten metal pump (30). The degassing chamber (20) is located adjacent and in fluid communication with the pump chamber (18), and houses a degassing mechanism (36). The filter chamber (22) is located adjacent and in fluid communication with the degassing chamber (20). The filter chamber (22) includes a molten metal filter (38). The melter furnace (12) is used to supply molten metal to an externally located holder furnace (14), which then recirculates molten metal back to the melter furnace (12).

  8. Metals processing control by counting molten metal droplets

    DOEpatents

    Schlienger, Eric; Robertson, Joanna M.; Melgaard, David; Shelmidine, Gregory J.; Van Den Avyle, James A.

    2000-01-01

    Apparatus and method for controlling metals processing (e.g., ESR) by melting a metal ingot and counting molten metal droplets during melting. An approximate amount of metal in each droplet is determined, and a melt rate is computed therefrom. Impedance of the melting circuit is monitored, such as by calculating by root mean square a voltage and current of the circuit and dividing the calculated current into the calculated voltage. Analysis of the impedance signal is performed to look for a trace characteristic of formation of a molten metal droplet, such as by examining skew rate, curvature, or a higher moment.

  9. Upgrading platform using alkali metals

    DOEpatents

    Gordon, John Howard

    2014-09-09

    A process for removing sulfur, nitrogen or metals from an oil feedstock (such as heavy oil, bitumen, shale oil, etc.) The method involves reacting the oil feedstock with an alkali metal and a radical capping substance. The alkali metal reacts with the metal, sulfur or nitrogen content to form one or more inorganic products and the radical capping substance reacts with the carbon and hydrogen content to form a hydrocarbon phase. The inorganic products may then be separated out from the hydrocarbon phase.

  10. Controlled in-situ dissolution of an alkali metal

    DOEpatents

    Jones, Jeffrey Donald; Dooley, Kirk John; Tolman, David Donald

    2012-09-11

    A method for the controllable dissolution of one or more alkali metals from a vessel containing a one or more alkali metals and/or one or more partially passivated alkali metals. The vessel preferably comprising a sodium, NaK or other alkali metal-cooled nuclear reactor that has been used. The alkali metal, preferably sodium, potassium or a combination thereof, in the vessel is exposed to a treatment liquid, preferably an acidic liquid, more preferably citric acid. Preferably, the treatment liquid is maintained in continuous motion relative to any surface of unreacted alkali metal with which the treatment liquid is in contact. The treatment liquid is preferably pumped into the vessel containing the one or more alkali metals and the resulting fluid is extracted and optionally further processed. Preferably, the resulting off-gases are processed by an off-gas treatment system and the resulting liquids are processed by a liquid disposal system. In one preferred embodiment, an inert gas is pumped into the vessel along with the treatment liquid.

  11. A method of measuring a molten metal liquid pool volume

    DOEpatents

    Garcia, G.V.; Carlson, N.M., Donaldson, A.D.

    1990-12-12

    A method of measuring a molten metal liquid pool volume and in particular molten titanium liquid pools, including the steps of (a) generating an ultrasonic wave at the surface of the molten metal liquid pool, (b) shining a light on the surface of a molten metal liquid pool, (c) detecting a change in the frequency of light, (d) detecting an ultrasonic wave echo at the surface of the molten metal liquid pool, and (e) computing the volume of the molten metal liquid. 3 figs.

  12. Process for recovering tritium from molten lithium metal

    DOEpatents

    Maroni, Victor A.

    1976-01-01

    Lithium tritide (LiT) is extracted from molten lithium metal that has been exposed to neutron irradiation for breeding tritium within a thermonuclear or fission reactor. The extraction is performed by intimately contacting the molten lithium metal with a molten lithium salt, for instance, lithium chloride - potassium chloride eutectic to distribute LiT between the salt and metal phases. The extracted tritium is recovered in gaseous form from the molten salt phase by a subsequent electrolytic or oxidation step.

  13. Method and apparatus for atomization and spraying of molten metals

    DOEpatents

    Hobson, David O.; Alexeff, Igor; Sikka, Vinod K.

    1990-01-01

    A method and device for dispersing molten metal into fine particulate spray, the method comprises applying an electric current through the molten metal and simultaneously applying a magnetic field to the molten metal in a plane perpendicular to the electric current, whereby the molten metal is caused to form into droplets at an angle perpendicular to both the electric current and the magnetic field. The device comprises a structure for providing a molten metal, appropriately arranged electrodes for applying an electric current through the molten metal, and a magnet for providing a magnetic field in a plane perpendicular to the electric current.

  14. Method of making alkali metal hydrides

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pecharsky, Vitalij K.; Gupta, Shalabh; Pruski, Marek

    A method is provided for making alkali metal hydrides by mechanochemically reacting alkali metal and hydrogen gas under mild temperature (e.g room temperature) and hydrogen pressure conditions without the need for catalyst, solvent, and intentional heating or cooling.

  15. Method and apparatus for atomization and spraying of molten metals

    DOEpatents

    Hobson, D.O.; Alexeff, I.; Sikka, V.K.

    1988-07-19

    A method and device for dispersing molten metal into fine particulate spray, the method comprises applying an electric current through the molten metal and simultaneously applying a magnetic field to the molten metal in a plane perpendicular to the electric current, whereby the molten metal is caused to form into droplets at an angle perpendicular to both the electric current and the magnetic field. The device comprises a structure for providing a molten metal, appropriately arranged electrodes for applying an electric current through the molten metal, and a magnet for providing a magnetic field in a plane perpendicular to the electric current. 11 figs.

  16. Method for recovering hydrocarbons from molten metal halides

    DOEpatents

    Pell, Melvyn B.

    1979-01-01

    In a process for hydrocracking heavy carbonaceous materials by contacting such carbonaceous materials with hydrogen in the presence of a molten metal halide catalyst to produce hydrocarbons having lower molecular weights and thereafter recovering the hydrocarbons so produced from the molten metal halide, an improvement comprising injecting into the spent molten metal halide, a liquid low-boiling hydrocarbon stream is disclosed.

  17. Spectroscopic studies of transition metal ions in molten alkali metal carboxylates

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maroni, V.A.; Maciejewski, M.L.

    Electronic absorption and C-13 NMR spectroscopic studies were carried out to investigate the structure of (i) alkali metal formate (Fm) and acetate (Ac) eutectic melts and (ii) solutions of 3d transition metal (TM) cations in these eutectics. Measurements were made over the temperature range 90..-->..190/sup 0/C. The most stable oxidation states of the individual TMs in the Fm and Ac eutectics were: Ti/sup 3 +/, V/sup 3 +/, VO/sup 2 +/, Cr/sup 3 +/, Mn/sup 2 +/, Fe/sup 2 +/, Co/sup 2 +/, Ni/sup 2 +/, and Cu/sup 2 +/. The ligand field absorption spectra obtained in these carboxylate meltsmore » bore a consistent resemblance to the spectra of these same cations in aqueous media, but the absorptivities were generally higher than are observed for the hexaquo complexes. The results were interpreted in terms of the existence of bidentate coordination in some (if not all) cases, leading to noncentrosymmetric complexation geometries. Key results of the NMR measurements included the apparent observation of two different carboxylate anion environments in Ni/sup 2 +/ solutions. C-13 spin-lattice relaxation of the carboxylate anions in the TM-free eutectics was found to be controlled by dipolar coupling to another nucleus. In the TM-containing solutions, the spin-lattice relaxation times were reduced by a factor of 10 to 1000, evidencing the expected shift to electron-nuclear dipolar coupling. Activation energies for viscous flow derived from the spin-lattice relaxation measurements on TM-free melts were in the 10..-->..11 kcal/mol range, reflecting the highly ordered, glassy nature of the eutectics studied.« less

  18. Electrolytic systems and methods for making metal halides and refining metals

    DOEpatents

    Holland, Justin M.; Cecala, David M.

    2015-05-26

    Disclosed are electrochemical cells and methods for producing a halide of a non-alkali metal and for electrorefining the halide. The systems typically involve an electrochemical cell having a cathode structure configured for dissolving a hydrogen halide that forms the halide into a molten salt of the halogen and an alkali metal. Typically a direct current voltage is applied across the cathode and an anode that is fabricated with the non-alkali metal such that the halide of the non-alkali metal is formed adjacent the anode. Electrorefining cells and methods involve applying a direct current voltage across the anode where the halide of the non-alkali metal is formed and the cathode where the non-alkali metal is electro-deposited. In a representative embodiment the halogen is chlorine, the alkali metal is lithium and the non-alkali metal is uranium.

  19. Alkali Metal Handling Practices at NASA MSFC

    NASA Technical Reports Server (NTRS)

    Salvail, Patrick G.; Carter, Robert R.

    2002-01-01

    NASA Marshall Space Flight Center (MSFC) is NASA s principle propulsion development center. Research and development is coordinated and carried out on not only the existing transportation systems, but also those that may be flown in the near future. Heat pipe cooled fast fission cores are among several concepts being considered for the Nuclear Systems Initiative. Marshall Space Flight Center has developed a capability to handle high-purity alkali metals for use in heat pipes or liquid metal heat transfer loops. This capability is a low budget prototype of an alkali metal handling system that would allow the production of flight qualified heat pipe modules or alkali metal loops. The processing approach used to introduce pure alkali metal into heat pipe modules and other test articles are described in this paper.

  20. 40 CFR 721.4660 - Alcohol, alkali metal salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alcohol, alkali metal salt. 721.4660... Substances § 721.4660 Alcohol, alkali metal salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as alcohol, alkali metal salt (PMN P-91-151) is...

  1. METAL SURFACE TREATMENT

    DOEpatents

    Eubank, L.D.

    1958-08-12

    Improved flux baths are described for use in conjunction with hot dipped coatings for uranium. The flux bath consists of molten alkali metal, or alkaline earth metal halides. One preferred embodiment comprises a bath containing molten KCl, NaCl, and LiCl in proportions approximating the triple eutectic.

  2. Recovery of alkali metal constituents from catalytic coal conversion residues

    DOEpatents

    Soung, W.Y.

    In a coal gasification operation (32) or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by contacting them with water or an aqueous solution to remove water-soluble alkali metal constituents and produce an aqueous solution enriched in said constituents. The aqueous solution thus produced is then contacted with carbon dioxide to precipitate silicon constituents, the pH of the resultant solution is increased, preferably to a value in the range between about 12.5 and about 15.0, and the solution of increased pH is evaporated to increase the alkali metal concentration. The concentrated aqueous solution is then recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

  3. Recovery of alkali metal constituents from catalytic coal conversion residues

    DOEpatents

    Soung, Wen Y.

    1984-01-01

    In a coal gasification operation (32) or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by contacting them (46, 53, 61, 69) with water or an aqueous solution to remove water-soluble alkali metal constituents and produce an aqueous solution enriched in said constituents. The aqueous solution thus produced is then contacted with carbon dioxide (63) to precipitate silicon constituents, the pH of the resultant solution is increased (81), preferably to a value in the range between about 12.5 and about 15.0, and the solution of increased pH is evaporated (84) to increase the alkali metal concentration. The concentrated aqueous solution is then recycled to the conversion process (86, 18, 17) where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

  4. Casting Apparatus Including A Gas Driven Molten Metal Injector And Method

    DOEpatents

    Meyer, Thomas N.

    2004-06-01

    The casting apparatus (50) includes a holding vessel (10) for containing a supply of molten metal (12) and a casting mold (52) located above the holding vessel (10) and having a casting cavity (54). A molten metal injector (14) extends into the holding vessel (10) and is at least partially immersed in the molten metal (12) in the holding vessel (10). The molten metal injector (14) is in fluid communication with the casting cavity (54). The molten metal injector (14) has an injector body (16) defining an inlet opening (24) for receiving molten metal into the injector body (16). A gas pressurization source (38) is in fluid communication with the injector body (16) for cyclically pressurizing the injector body (16) and inducing molten metal to flow from the injector body (16) to the casting cavity (54). An inlet valve (42) is located in the inlet opening (24) in the injector body (16) for filling molten metal into the injector body (16). The inlet valve (42) is configured to prevent outflow of molten metal from the injector body (16) during pressurization and permit inflow of molten metal into the injector body (16) after pressurization. The inlet valve (42) has an inlet valve actuator (44) located above the surface of the supply of molten metal (12) and is operatively connected to the inlet valve (42) for operating the inlet valve (42) between open and closed positions.

  5. Ternary alkali-metal and transition metal or metalloid acetylides as alkali-metal intercalation electrodes for batteries

    DOEpatents

    Nemeth, Karoly; Srajer, George; Harkay, Katherine C; Terdik, Joseph Z

    2015-02-10

    Novel intercalation electrode materials including ternary acetylides of chemical formula: A.sub.nMC.sub.2 where A is alkali or alkaline-earth element; M is transition metal or metalloid element; C.sub.2 is reference to the acetylide ion; n is an integer that is 0, 1, 2, 3 or 4 when A is alkali element and 0, 1, or 2 when A is alkaline-earth element. The alkali elements are Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). The alkaline-earth elements are Berilium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). M is a transition metal that is any element in groups 3 through 12 inclusive on the Periodic Table of Elements (elements 21 (Sc) to element 30 (Zn)). In another exemplary embodiment, M is a metalloid element.

  6. Recovery of protactinium from molten fluoride nuclear fuel compositions

    DOEpatents

    Baes, C.F. Jr.; Bamberger, C.; Ross, R.G.

    1973-12-25

    A method is provided for separating protactinium from a molten fluonlde salt composition consisting essentially of at least one alkali and alkaline earth metal fluoride and at least one soluble fluoride of uranium or thorium which comprises oxidizing the protactinium in said composition to the + 5 oxidation state and contacting said composition with an oxide selected from the group consisting of an alkali metal oxide, an alkaline earth oxide, thorium oxide, and uranium oxide, and thereafter isolating the resultant insoluble protactinium oxide product from said composition. (Official Gazette)

  7. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for the...

  8. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for the...

  9. Salts of alkali metal anions and process of preparing same

    DOEpatents

    Dye, James L.; Ceraso, Joseph M.; Tehan, Frederick J.; Lok, Mei Tak

    1978-01-01

    Compounds of alkali metal anion salts of alkali metal cations in bicyclic polyoxadiamines are disclosed. The salts are prepared by contacting an excess of alkali metal with an alkali metal dissolving solution consisting of a bicyclic polyoxadiamine in a suitable solvent, and recovered by precipitation. The salts have a gold-color crystalline appearance and are stable in a vacuum at -10.degree. C. and below.

  10. Al/Cl2 molten salt battery

    NASA Technical Reports Server (NTRS)

    Giner, J.

    1972-01-01

    Molten salt battery has been developed with theoretical energy density of 5.2 j/kg (650 W-h/lb). Battery, which operates at 150 C, can be used in primary mode or as rechargeable battery. Battery has aluminum anode and chlorine cathode. Electrolyte is mixture of AlCl3, NaCl, and some alkali metal halide such as KCl.

  11. Process for the disposal of alkali metals

    DOEpatents

    Lewis, Leroy C.

    1977-01-01

    Large quantities of alkali metals may be safely reacted for ultimate disposal by contact with a hot concentrated caustic solution. The alkali metals react with water in the caustic solution in a controlled reaction while steam dilutes the hydrogen formed by the reaction to a safe level.

  12. Oxidation of hydrogen halides to elemental halogens with catalytic molten salt mixtures

    DOEpatents

    Rohrmann, Charles A.

    1978-01-01

    A process for oxidizing hydrogen halides by means of a catalytically active molten salt is disclosed. The subject hydrogen halide is contacted with a molten salt containing an oxygen compound of vanadium and alkali metal sulfates and pyrosulfates to produce an effluent gas stream rich in the elemental halogen. The reduced vanadium which remains after this contacting is regenerated to the active higher valence state by contacting the spent molten salt with a stream of oxygen-bearing gas.

  13. Castable cements to prevent corrosion of metals in molten salts

    DOE PAGES

    Gomez-Vidal, Judith C.; Morton, E.

    2016-04-22

    Castable cements on metals form a protective barrier that is able to prevent permeation of molten salts towards metallic surfaces. Silica-based castable cements are capable of protecting containment metallic alloys from the corrosive attack of molten chlorides at temperatures as high as 650 °C. Boron nitride (BN) blocking the pores in the cured cement prevents permeation of the molten chloride towards the metal surface. The cements tested are not chemically stable in molten carbonates, because the bonding components dissolved into molten carbonates salt. The corrosion rate is 7.72±0.32 mm/year for bare stainless steel 347 in molten eutectic NaCl – 65.58more » wt% LiCl at 650 °C, which is the baseline used for determining how well the cement protects the metallic surfaces from corrosion. In particular the metal fully encapsulated with Aremco 645-N with pores filled with boron nitride immersed in molten eutectic NaCl – 65.58 wt% LiCl at 650 °C shows a corrosion rate of 9E-04 mm/year. Here, the present study gives initial corrosion rates. Long-term tests are required to determine if Aremco 645-N with BN coating on metal has long term chemical stability for blocking salt permeation through coating pores.« less

  14. Pendant-Drop Surface-Tension Measurement On Molten Metal

    NASA Technical Reports Server (NTRS)

    Man, Kin Fung; Thiessen, David

    1996-01-01

    Method of measuring surface tension of molten metal based on pendant-drop method implemented in quasi-containerless manner and augmented with digital processing of image data. Electrons bombard lower end of sample rod in vacuum, generating hanging drop of molten metal. Surface tension of drop computed from its shape. Technique minimizes effects of contamination.

  15. Alkali metal intercalates of molybdenum disulfide.

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.; Hadek, V.; Rembaum, A.

    1973-01-01

    Study of some of the physicochemical properties of compounds obtained by subjecting natural molybdenite and single crystals of molybdenum disulfide grown by chemical vapor transport to intercalation with the alkali group of metals (Li, Na, K, Rb, and Cs) by means of the liquid ammonia technique. Reported data and results include: (1) the intercalation of the entire alkali metal group, (2) stoichiometries and X-ray data on all of the compounds, and (3) superconductivity data for all the intercalation compounds.

  16. Alkali Metal/Salt Thermal-Energy-Storage Systems

    NASA Technical Reports Server (NTRS)

    Phillips, Wayne W.; Stearns, John W.

    1987-01-01

    Proposed thermal-energy-storage system based on mixture of alkali metal and one of its halide salts; metal and salt form slurry of two immiscible melts. Use of slurry expected to prevent incrustations of solidified salts on heat-transfer surfaces that occur where salts alone used. Since incrustations impede heat transfer, system performance improved. In system, charging heat-exchanger surface immersed in lower liquid, rich in halide-salt, phase-charge material. Discharging heat exchanger surface immersed in upper liquid, rich in alkali metal.

  17. COMPLEX FLUORIDES OF PLUTONIUM AND AN ALKALI METAL

    DOEpatents

    Seaborg, G.T.

    1960-08-01

    A method is given for precipitating alkali metal plutonium fluorides. such as KPuF/sub 5/, KPu/sub 2/F/sub 9/, NaPuF/sub 5/, and RbPuF/sub 5/, from an aqueous plutonium(IV) solution by adding hydrogen fluoride and alkali-metal- fluoride.

  18. Electronic structure of semiconducting alkali-metal silicides and germanides

    NASA Astrophysics Data System (ADS)

    Tegze, M.; Hafner, J.

    1989-11-01

    We present self-consistent linearized-muffin-tin-orbital calculations of the electronic structure of three alkali-metal germanides and silicides (KGe, NaGe, and NaSi). Like the alkali-metal-lead compounds investigated in our earlier work [M. Tegze and J. Hafner, Phys. Rev. B 39, 8263 (1989)] the Ge and Si compounds of the alkali metals form complex structures based on the packing of tetrahedral Ge4 and Si4 clusters. Our calculations show that all three compounds are narrow-gap semiconductors. The width of the energy gap depends on two main factors: the ratio of the intracluster to the intercluster interactions between the group-IV elements (which increases from Pb to Si) and the strength of the interactions between the alkali-metal atoms (which varies with the size ratio).

  19. Molten metal feed system controlled with a traveling magnetic field

    DOEpatents

    Praeg, Walter F.

    1991-01-01

    A continuous metal casting system in which the feed of molten metal is controlled by means of a linear induction motor capable of producing a magnetic traveling wave in a duct that connects a reservoir of molten metal to a caster. The linear induction motor produces a traveling magnetic wave in the duct in opposition to the pressure exerted by the head of molten metal in the reservoir so that p.sub.c =p.sub.g -p.sub.m where p.sub.c is the desired pressure in the caster, p.sub.g is the gravitational pressure in the duct exerted by the force of the head of molten metal in the reservoir, and p.sub.m is the electromagnetic pressure exerted by the force of the magnetic field traveling wave produced by the linear induction motor. The invention also includes feedback loops to the linear induction motor to control the casting pressure in response to measured characteristics of the metal being cast.

  20. 40 CFR 721.5452 - Alkali metal salt of halogenated organoborate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkali metal salt of halogenated... Specific Chemical Substances § 721.5452 Alkali metal salt of halogenated organoborate (generic). (a... generically as alkali metal salt of halogenated organoborate (PMN P-00-0638) is subject to reporting under...

  1. 40 CFR 721.5452 - Alkali metal salt of halogenated organoborate (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal salt of halogenated... Specific Chemical Substances § 721.5452 Alkali metal salt of halogenated organoborate (generic). (a... generically as alkali metal salt of halogenated organoborate (PMN P-00-0638) is subject to reporting under...

  2. 40 CFR 721.4660 - Alcohol, alkali metal salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alcohol, alkali metal salt. 721.4660 Section 721.4660 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4660 Alcohol, alkali metal sal...

  3. Molten metal reactor and method of forming hydrogen, carbon monoxide and carbon dioxide using the molten alkaline metal reactor

    DOEpatents

    Bingham, Dennis N.; Klingler, Kerry M.; Turner, Terry D.; Wilding, Bruce M.

    2012-11-13

    A molten metal reactor for converting a carbon material and steam into a gas comprising hydrogen, carbon monoxide, and carbon dioxide is disclosed. The reactor includes an interior crucible having a portion contained within an exterior crucible. The interior crucible includes an inlet and an outlet; the outlet leads to the exterior crucible and may comprise a diffuser. The exterior crucible may contain a molten alkaline metal compound. Contained between the exterior crucible and the interior crucible is at least one baffle.

  4. 40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under this...

  5. 40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under this...

  6. Online monitoring of corrosion behavior in molten metal using laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Zeng, Qiang; Pan, Congyuan; Li, Chaoyang; Fei, Teng; Ding, Xiaokang; Du, Xuewei; Wang, Qiuping

    2018-04-01

    The corrosion behavior of structure materials in direct contact with molten metals is widespread in metallurgical industry. The corrosion of casting equipment by molten metals is detrimental to the production process, and the corroded materials can also contaminate the metals being produced. Conventional methods for studying the corrosion behavior by molten metal are offline. This work explored the application of laser-induced breakdown spectroscopy (LIBS) for online monitoring of the corrosion behavior of molten metal. The compositional changes of molten aluminum in crucibles made of 304 stainless steel were obtained online at 1000 °C. Several offline techniques were combined to determine the corrosion mechanism, which was highly consistent with previous studies. Results proved that LIBS was an efficient method to study the corrosion mechanism of solid materials in molten metal.

  7. Studies of metals electroprocessing in molten salts

    NASA Technical Reports Server (NTRS)

    Sadoway, D. R.

    1982-01-01

    Fluid flow patterns in molten salt electrolytes were observed in order to determine how mass transport affects the morphology of the metal deposit. Studies conducted on the same metal, both in aqueous electrolytes in which coherent solid electrodeposits are produced, as well as in transparent molten salt electrolytes are described. Process variables such as current density and composition of the electrolyte are adjusted to change the morphology of the electrodeposit and, thus, to permit the study of the nature of electrolyte flow in relation to the quality of the electrodeposit.

  8. All ceramic structure for molten carbonate fuel cell

    DOEpatents

    Smith, James L.; Kucera, Eugenia H.

    1992-01-01

    An all-ceramic molten carbonate fuel cell having a composition formed of a multivalent metal oxide or oxygenate such as an alkali metal, transition metal oxygenate. The structure includes an anode and cathode separated by an electronically conductive interconnect. The electrodes and interconnect are compositions ceramic materials. Various combinations of ceramic compositions for the anode, cathode and interconnect are disclosed. The fuel cell exhibits stability in the fuel gas and oxidizing environments. It presents reduced sealing and expansion problems in fabrication and has improved long-term corrosion resistance.

  9. 40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... metal salts. 721.4663 Section 721.4663 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4663 Fluorinated carboxylic acid alkali metal salts. (a) Chemical... fluorinated carboxylic acid alkali metal salts (PMNs P-95-979/980/981) are subject to reporting under this...

  10. Compact, Lightweight Electromagnetic Pump for Liquid Metal

    NASA Technical Reports Server (NTRS)

    Godfroy, Thomas; Palzin, Kurt

    2010-01-01

    A proposed direct-current electromagnetic pump for circulating a molten alkali metal alloy would be smaller and lighter and would demand less input power, relative to currently available pumps of this type. (Molten alkali metals are used as heat-transfer fluids in high-temperature stages of some nuclear reactors.) The principle of operation of this or any such pump involves exploitation of the electrical conductivity of the molten metal: An electric current is made to pass through the liquid metal along an axis perpendicular to the longitudinal axis of the flow channel, and a magnetic field perpendicular to both the longitudinal axis and the electric current is superimposed on the flowchannel region containing the electric current. The interaction between the electric current and the magnetic field produces the pumping force along the longitudinal axis. The advantages of the proposed pump over other such pumps would accrue from design features that address overlapping thermal and magnetic issues.

  11. Pressurized tundish for controlling a continuous flow of molten metal

    DOEpatents

    Lewis, T.W.; Hamill, P.E. Jr.; Ozgu, M.R.; Padfield, R.C.; Rego, D.N.; Brita, G.P.

    1990-07-24

    A pressurized tundish for controlling a continuous flow of molten metal is characterized by having a pair of principal compartments, one being essentially unpressurized and receiving molten metal introduced thereto, and the other being adapted for maintaining a controlled gaseous pressure over the surface of the fluid metal therein, whereby, by controlling the pressure within the pressurized chamber, metal exiting from the tundish is made to flow continually and at a controlled rate. 1 fig.

  12. Pressurized tundish for controlling a continuous flow of molten metal

    DOEpatents

    Lewis, Thomas W.; Hamill, Jr., Paul E.; Ozgu, Mustafa R.; Padfield, Ralph C.; Rego, Donovan N.; Brita, Guido P.

    1990-01-01

    A pressurized tundish for controlling a continous flow of molten metal characterized by having a pair of principal compartments, one being essentially unpressurized and receiving molten metal introduced thereto, and the other being adapted for maintaining a controlled gaseous pressure over the surface of the fluid metal therein, whereby, by controlling the pressure within the pressurized chamber, metal exiting from the tundish is made to flow continually and at a controlled rate.

  13. Electromagnetic confinement for vertical casting or containing molten metal

    DOEpatents

    Lari, Robert J.; Praeg, Walter F.; Turner, Larry R.

    1991-01-01

    An apparatus and method adapted to confine a molten metal to a region by means of an alternating electromagnetic field. As adapted for use in the present invention, the alternating electromagnetic field given by B.sub.y =(2.mu..sub.o .rho.gy).sup.1/2 (where B.sub.y is the vertical component of the magnetic field generated by the magnet at the boundary of the region; y is the distance measured downward form the top of the region, .rho. is the metal density, g is the acceleration of gravity and .mu..sub.o is the permeability of free space) induces eddy currents in the molten metal which interact with the magnetic field to retain the molten metal with a vertical boudnary. As applied to an apparatus for the continuous casting of metal sheets or rods, metal in liquid form can be continuously introduced into the region defined by the magnetic field, solidified and conveyed away from the magnetic field in solid form in a continuous process.

  14. Alkali metal vapors - Laser spectroscopy and applications

    NASA Technical Reports Server (NTRS)

    Stwalley, W. C.; Koch, M. E.

    1980-01-01

    The paper examines the rapidly expanding use of lasers for spectroscopic studies of alkali metal vapors. Since the alkali metals (lithium, sodium, potassium, rubidium and cesium) are theoretically simple ('visible hydrogen'), readily ionized, and strongly interacting with laser light, they represent ideal systems for quantitative understanding of microscopic interconversion mechanisms between photon (e.g., solar or laser), chemical, electrical and thermal energy. The possible implications of such understanding for a wide variety of practical applications (sodium lamps, thermionic converters, magnetohydrodynamic devices, new lasers, 'lithium waterfall' inertial confinement fusion reactors, etc.) are also discussed.

  15. 40 CFR 721.10097 - Disubstituted benzenesulfonic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., alkali metal salt (generic). 721.10097 Section 721.10097 Protection of Environment ENVIRONMENTAL... metal salt (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as disubstituted benzenesulfonic acid, alkali metal salt (PMN P...

  16. 40 CFR 721.10097 - Disubstituted benzenesulfonic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., alkali metal salt (generic). 721.10097 Section 721.10097 Protection of Environment ENVIRONMENTAL... metal salt (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as disubstituted benzenesulfonic acid, alkali metal salt (PMN P...

  17. Neuropsychiatric manifestations of alkali metal deficiency and excess

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yung, C.Y.

    1984-01-01

    The alkali metals from the Group IA of the periodic table (lithium, sodium, potassium, rubidium, cesium and francium) are reviewed. The neuropsychiatric aspects of alkali metal deficiencies and excesses (intoxications) are described. Emphasis was placed on lithium due to its clinical uses. The signs and symptoms of these conditions are characterized by features of an organic brain syndrome with delirium and encephalopathy prevailing. There are no clinically distinctive features that could be reliably used for diagnoses. Sodium and potassium are two essential alkali metals in man. Lithium is used as therapeutic agent in bipolar affective disorders. Rubidium has been investigatedmore » for its antidepressant effect in a group of psychiatric disorders. Cesium is under laboratory investigation for its role in carcinogenesis and in depressive illness. Very little is known of francium due to its great instability for experimental study.« less

  18. 40 CFR 721.10098 - Disubstituted benzoic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... metal salt (generic). 721.10098 Section 721.10098 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10098 Disubstituted benzoic acid, alkali metal salt... identified generically as disubstituted benzoic acid, alkali metal salt (PMN P-03-643) is subject to...

  19. 40 CFR 721.10098 - Disubstituted benzoic acid, alkali metal salt (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... metal salt (generic). 721.10098 Section 721.10098 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10098 Disubstituted benzoic acid, alkali metal salt... identified generically as disubstituted benzoic acid, alkali metal salt (PMN P-03-643) is subject to...

  20. Corrosion-electrochemical behavior of zirconium in molten alkali metal carbonates

    NASA Astrophysics Data System (ADS)

    Nikitina, E. V.

    2016-08-01

    The corrosion and electrochemical characteristics of zirconium during its interaction with molten lithium, sodium, and potassium carbonates containing from 1 to 5 wt % additives to the salt phase are studied in a temperature range of 500-800°C using gravimetry, corrosion potential measurement, and anodic polarization. The substances decreasing the corrosion losses due to the strengthening and thickening of an oxide film (lithium, sodium, potassium hydroxides) are used as passivators. Sodium chloride, fluoride, and sulfate serve as corrosion stimulators (activators).

  1. Effects of pH on frog gustatory responses to chloride salts of alkali-metal and alkali-earth-metal.

    PubMed

    Kumai, T; Nomura, H

    1980-01-01

    The pH effects on frog gustatory responses to alkali-metal and alkali-earth-metal chloride salts were examined using single fungi-form papilla preparations. Responses to 0.1-0.5 M NaCl were clearly dependent upon the pH of the stimulating solutions. The responses increased as the pH decreased from 6.5 to 4.5 and were almost completely suppressed at pH's above 6.5. There was no significant difference in the pH dependency of the response among alkali-metal chlorides. HCl solutions elicited only a poor response under conditions in which the water response was suppressed by the simultaneous presence of a low NaCl concentration. Responses to alkali-earth-metal chlorides varied in their pH dependency. Response to CaCl2 was slightly affected by pH changes from 4.5 to 9.0, response to SrCl2 was considerably suppressed in the alkaline region, and responses to BaCl2 and MgCl2 were strongly suppressed at pH's above 6.5. BeCl2 solutions showed less marked stimulating effects over the pH range tested. The differences in pH dependency described above suggest the existence of two kinds of receptor sites, one being pH-insensitive sites responsible for the calcium response and the other pH-sensitive sites responsible for the sodium response. A cross-adaptation test appeared to support this possibility. Assuming that the pH effect mentioned is related to changes in the state of ionization of the receptor molecule, the pKa of the ionizable group responsible for the sodium response was determined to be approximately 5.5.

  2. Method of assembling and sealing an alkali metal battery

    DOEpatents

    Elkins, Perry E.; Bell, Jerry E.; Harlow, Richard A.; Chase, Gordon G.

    1983-01-01

    A method of initially assembling and then subsequently hermetically sealing a container portion of an alkali metal battery to a ceramic portion of such a battery is disclosed. Sealing surfaces are formed respectively on a container portion and a ceramic portion of an alkali metal battery. These sealing surfaces are brought into juxtaposition and a material is interposed therebetween. This interposed material is one which will diffuse into sealing relationship with both the container portion and the ceramic portion of the alkali metal battery at operational temperatures of such a battery. A pressure is applied between these sealing surfaces to cause the interposed material to be brought into intimate physical contact with such juxtaposed surfaces. A temporary sealing material which will provide a seal against a flow of alkali metal battery reactants therethrough at room temperatures and is applied over the juxtaposed sealing surfaces and material interposed therebetween. The entire assembly is heated to an operational temperature so that the interposed material diffuses into the container portion and the ceramic portion to form a hermetic seal therebetween. The pressure applied to the juxtaposed sealing surfaces is maintained in order to ensure the continuation of the hermetic seal.

  3. 30 CFR 57.16013 - Working with molten metal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Working with molten metal. 57.16013 Section 57.16013 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Materials...

  4. 30 CFR 57.16013 - Working with molten metal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Working with molten metal. 57.16013 Section 57.16013 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Materials...

  5. Wetting and spreading behavior of molten brazing filler metallic alloys on metallic substrate

    NASA Astrophysics Data System (ADS)

    Kogi, Satoshi; Kajiura, Tetsurou; Hanada, Yukiakira; Miyazawa, Yasuyuki

    2014-08-01

    Wetting and spreading of molten brazing filler material are important factors that influence the brazing ability of a joint to be brazed. Several investigations into the wetting ability of a brazing filler alloy and its surface tension in molten state, in addition to effects of brazing time and temperature on the contact angle, have been carried out. In general, dissimilar-metals brazing technology and high-performance brazed joint are necessities for the manufacturing field in the near future. Therefore, to address this requirement, more such studies on wetting and spreading of filler material are required for a deeper understanding. Generally, surface roughness and surface conditions affect spreading of molten brazing filler material during brazing. Wetting by and interfacial reactions of the molten brazing filler material with the metallic substrate, especially, affect strongly the spreading of the filler material. In this study, the effects of surface roughness and surface conditions on the spreading of molten brazing filler metallic alloys were investigated. Ag-(40-x)Cu-xIn and Ag- (40-x)Cu-xSn (x=5, 10, 15, 20, 25) alloys were used as brazing filler materials. A mild-steel square plate (S45C (JIS); side: 30 mm; thickness: 3mm) was employed as the substrate. A few surfaces with varying roughness were prepared using emery paper. Brazing filler material and metallic base plate were first washed with acetone, and then a flux was applied to them. The filler, 50 mg, was placed on the center of the metallic base with the flux. A spreading test was performed under Ar gas using an electrically heated furnace, after which, the original spreading area, defined as the sessile drop area, and the apparent spreading area, produced by the capillary grooves, were both evaluated. It was observed that the spreading area decreased with increasing In and Sn content.

  6. Guanidine hydrochloride-induced alkali molten globule model of horse ferrocytochrome c.

    PubMed

    Jain, Rishu; Kaur, Sandeep; Kumar, Rajesh

    2013-02-01

    This article compares structural, kinetic and thermodynamic properties of previously unknown guanidine hydrochloride (GdnHCl)-induced alkali molten globule (MG) state of horse 'ferrocytochrome c' (ferrocyt c) with the known NaCl-induced alkali-MG state of ferrocyt c. It is well known that Cl(-) arising from GdnHCl refolds and stabilizes the acid-denatured protein to MG state. We demonstrate that the GdnH(+) arising from GdnHCl (≤0.2 M) also transforms the base-denatured CO-liganded ferrocyt c (carbonmonoxycyt c) to MG state by making the electrostatic interactions to the negative charges of the protein. Structural and molecular properties extracted from the basic spectroscopic (circular dichroism (CD), fluorescence, FTIR and NMR) experiments suggest that the GdnH(+)- and Na(+)-induced MG states of base-denatured carbonmonoxycyt c are molecular compact states containing native-like secondary structures and disordered tertiary structures. Kinetic experiments involving the measurement of the CO association to the alkaline ferrocyt c in the presence of different GdnHCl and NaCl concentrations indicate that the Na(+)-induced MG state is more constrained relative to that of GdnH(+)-induced MG state. Analyses of thermal (near UV-CD) denaturation curves of the base-denatured protein in the presence of different GdnHCl and NaCl concentration also indicate that the Na(+)-induced MG state is thermally more stable than the GdnH(+)-induced MG state.

  7. 30 CFR 56.16013 - Working with molten metal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Working with molten metal. 56.16013 Section 56.16013 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Materials Storage...

  8. 30 CFR 56.16013 - Working with molten metal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Working with molten metal. 56.16013 Section 56.16013 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Materials Storage...

  9. Solvent- and catalyst-free mechanochemical synthesis of alkali metal monohydrides

    DOE PAGES

    Hlova, Ihor Z.; Castle, Andra; Goldston, Jennifer F.; ...

    2016-07-06

    Alkali metal monohydrides, AH (A = Li–Cs) have been synthesized in quantitative yields at room temperature by reactive milling of alkali metals in the presence of hydrogen gas at 200 bar or less. The mechanochemical approach reported here eliminates problems associated with the malleability of alkali metals — especially Li, Na, and K — and promotes effective solid–gas reactions, ensuring their completion. This is achieved by incorporating a certain volume fraction of the corresponding hydride powder as a process control agent, which allows continuous and efficient milling primarily by coating the surface of metal particles, effectively blocking cold welding. Formationmore » of high-purity crystalline monohydrides has been confirmed by powder X-ray diffraction, solid-state NMR spectroscopy, and volumetric analyses of reactively desorbed H 2 from as-milled samples. The proposed synthesis method is scalable and particularly effective for extremely air-sensitive materials, such as alkali and alkaline earth metal hydrides. Furthermore, the technique may also be favorable for production in continuous reactors operating at room temperature, thereby reducing the total processing time, energy consumption and, hence, the cost of production of these hydrides or their derivatives and composites.« less

  10. Method of assembling and sealing an alkali metal battery

    DOEpatents

    Elkins, P.E.; Bell, J.E.; Harlow, R.A.; Chase, G.G.

    1983-03-01

    A method of initially assembling and then subsequently hermetically sealing a container portion of an alkali metal battery to a ceramic portion of such a battery is disclosed. Sealing surfaces are formed respectively on a container portion and a ceramic portion of an alkali metal battery. These sealing surfaces are brought into juxtaposition and a material is interposed there between. This interposed material is one which will diffuse into sealing relationship with both the container portion and the ceramic portion of the alkali metal battery at operational temperatures of such a battery. A pressure is applied between these sealing surfaces to cause the interposed material to be brought into intimate physical contact with such juxtaposed surfaces. A temporary sealing material which will provide a seal against a flow of alkali metal battery reactants there through at room temperatures and is applied over the juxtaposed sealing surfaces and material interposed there between. The entire assembly is heated to an operational temperature so that the interposed material diffuses into the container portion and the ceramic portion to form a hermetic seal there between. The pressure applied to the juxtaposed sealing surfaces is maintained in order to ensure the continuation of the hermetic seal. 4 figs.

  11. Method and composition for testing for the presence of an alkali metal

    DOEpatents

    Guon, Jerold

    1981-01-01

    A method and composition for detecting the presence of an alkali metal on the surface of a body such as a metal plate, tank, pipe or the like is provided. The method comprises contacting the surface with a thin film of a liquid composition comprising a light-colored pigment, an acid-base indicator, and a nonionic wetting agent dispersed in a liquid carrier comprising a minor amount of water and a major amount of an organic solvent selected from the group consisting of the lower aliphatic alcohols, ketones and ethers. Any alkali metal present on the surface in elemental form or as an alkali metal hydroxide or alkali metal carbonate will react with the acid-base indicator to produce a contrasting color change in the thin film, which is readily discernible by visual observation or automatic techniques.

  12. Chronopotentiometry of refractory metals, actinides and oxyanions in molten salts: A review

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.

    1992-01-01

    The applications of chronopotentiometry to the study of electrochemical behavior of three technologically important areas of refractory metals, actinides, and oxyanions in molten salts are critically reviewed. Chronopotentiometry is a very versatile diagnostic tool to understand the reaction mechanism of the electrode processes for the electrochemical reduction/oxidation of these electroactive species in molten salt solutions. Well adherent, compact, and uniformly thick coatings of refractory metals may be electrodeposited from their solutions in molten salts.

  13. The interactions of sorbates with gallosilicates and alkali-metal exchanged gallosilicates

    NASA Astrophysics Data System (ADS)

    Limtrakul, J.; Kuno, M.; Treesukol, P.

    1999-11-01

    Structures, energetics and vibrational frequencies of the interaction of adsorbates with H-aluminosilicates (H-AlZ), H-gallosilicates (H-GaZ), alkali-metal exchanged aluminosilicates (X-AlZ) and alkali-metal exchanged gallosilicates (X-GaZ), where X being Li, Na, or K, have been carried out at B3LYP and HF levels of theory with 6-31G(d) as the basis set. The charge compensating alkali-metal ions can affect the catalytically active site (Si-O-T where T=Al or Ga) by weakening the Si-O, Al-O, and Ga-O bonds as compared to their anionic frameworks. Comparing the net stabilization energies, Δ ENSE, of the naked alkali-metal/H 2O adducts with those of the alkali-metal exchanged zeolite/H 2O systems, the latter amounts only to about 50% of the former, which is partly due to the destabilizing role of the negative zeolitic oxygen frameworks surrounding the cations. The interaction of sorbates with the alkali-metal exchanged gallosilicates can be employed to probe the field strength inside the catalytic frameworks as indicated by the plot of the binding energy, Δ E, versus 1/ RX-O w2, with R(X-O w) being the distance between the cationic nucleus and the oxygen atom of the adsorbate. The IR spectra of H 2O adsorbed on Na-AlZ are calculated to be 3584, 3651, and 1686 cm -1. The obtained results are in excellent agreement with the very recent experimental IR spectra of water adsorbed on Na-ZSM-5 of Zecchina et al. (J. Phys. Chem., 100 (1996) 16 484). Other important features, i.e. the correlation between Δ νOH and, Δ E, R(X-O w) , and 1/ RX-O w2, cationic size, demonstrate that the interactions of sorbates with alkali-metal exchanged gallosilicates are well approximated by electrostatic contribution.

  14. An Assessment of Molten Metal Detachment Hazards During Electron Beam Welding in Space

    NASA Technical Reports Server (NTRS)

    Fragomeni, James M.; Nunes, Arthur C., Jr.

    1998-01-01

    The safety issue has been raised with regards to potential molten metal detachments from the weld pool and cold filler wire during electron beam welding in space. This investigation was undertaken to evaluate if molten metal could detach and come in contact with astronauts and burn through the fabric of the astronauts' Extravehicular Mobility Unit (EMU) during electron beam welding in space. Molten metal detachments from either the weld/cut substrate or weld wire could present harm to a astronaut if the detachment was to burn through the fabric of the EMU. Theoretical models were developed to predict the possibility and size of the molten metal detachment hazards during the electron beam welding exercises at Low Earth Orbit (LEO). The primary molten metal detachment concerns were those cases of molten metal separation from the metal surface due to metal cutting, weld pool splashing, entrainment and release of molten metal due to filler wire snap-out from the weld puddle, and molten metal accumulation and release from the end of the weld wire. Some possible ways of obtaining molten metal drop detachments would include an impulse force, or bump, to the weld sample, cut surface, or filler wire. Theoretical models were developed for these detachment concerns from principles of impact and kinetic energies, surface tension, drop geometry, surface energies, and particle dynamics. The surface tension represents the force opposing the liquid metal drop from detaching whereas the weight of the liquid metal droplet represents a force that is tending to detach the molten metal drop. Theoretical calculations have indicated that only a small amount of energy is required to detach a liquid metal drop; however, much of the energy of an impact is absorbed in the sample or weld plate before it reaches the metal drop on the cut edge or surface. The tendency for detachment is directly proportional to the weld pool radius and metal density and inversely proportional to the surface

  15. An Assessment of Molten Metal Detachment Hazards During Electron Beam Welding in Space

    NASA Technical Reports Server (NTRS)

    Fragomeni, James M.; Nunes, Arthur C., Jr.

    1998-01-01

    The safety issue has been raised with regards to potential molten metal detachments from the weld pool and cold filler wire during electron beam welding in space. This investigation was undertaken to evaluate if molten metal could detach and come in contact with astronauts and burn through the fabric of the astronauts' Extravehicular Mobility Unit (EMU) during electron beam welding in space. Molten metal detachments from either the weld/cut substrate or weld wire could present harm to a astronaut if the detachment was to burn through the fabric of the EMU. Theoretical models were developed to predict the possibility and size of the molten metal detachment hazards during the electron beam welding exercises at Low Earth Orbit (LEO). The primary molten metal detachment concerns were those cases of molten metal separation from the metal surface due to metal cutting, weld pool splashing, entrainment and release of molten metal due to filler wire snap-out from the weld puddle, and molten metal accumulation and release from the end of the weld wire. Some possible ways of obtaining molten metal drop detachments would include an impulse force, or bump, to the weld sample, cut surface, or filler wire. Theoretical models were developed for these detachment concerns from principles of impact and kinetic energies, surface tension, drop geometry, surface energies, and particle dynamics. The surface tension represents the force opposing the liquid metal drop from detaching whereas the weight of the liquid metal droplet represents a force that is tending to detach the molten metal drop. Theoretical calculations have indicated that only a small amount of energy is required to detach a liquid metal drop; however, much of the energy of an impact is absorbed in the sample or weld plate before it reaches the metal drop on the cut edge or surface. The tendency for detachment is directly proportional to the weld pool radius and metal density and inversely proportional to the surface

  16. Role of crystal field in mixed alkali metal effect: electron paramagnetic resonance study of mixed alkali metal oxyfluoro vanadate glasses.

    PubMed

    Honnavar, Gajanan V; Ramesh, K P; Bhat, S V

    2014-01-23

    The mixed alkali metal effect is a long-standing problem in glasses. Electron paramagnetic resonance (EPR) is used by several researchers to study the mixed alkali metal effect, but a detailed analysis of the nearest neighbor environment of the glass former using spin-Hamiltonian parameters was elusive. In this study we have prepared a series of vanadate glasses having general formula (mol %) 40 V2O5-30BaF2-(30 - x)LiF-xRbF with x = 5, 10, 15, 20, 25, and 30. Spin-Hamiltonian parameters of V(4+) ions were extracted by simulating and fitting to the experimental spectra using EasySpin. From the analysis of these parameters it is observed that the replacement of lithium ions by rubidium ions follows a "preferential substitution model". Using this proposed model, we were able to account for the observed variation in the ratio of the g parameter, which goes through a maximum. This reflects an asymmetric to symmetric changeover of the alkali metal ion environment around the vanadium site. Further, this model also accounts for the variation in oxidation state of vanadium ion, which was confirmed from the variation in signal intensity of EPR spectra.

  17. Method of removal of heavy metal from molten salt in IFR fuel pyroprocessing

    DOEpatents

    Gay, Eddie C.

    1995-01-01

    An electrochemical method of separating heavy metal values from a radioactive molten salt including Li halide at temperatures of about 500.degree. C. The method comprises positioning a solid Li--Cd alloy anode in the molten salt containing the heavy metal values, positioning a Cd-containing cathode or a solid cathode positioned above a catch crucible in the molten salt to recover the heavy metal values, establishing a voltage drop between the anode and the cathode to deposit material at the cathode to reduce the concentration of heavy metals in the salt, and controlling the deposition rate at the cathode by controlling the current between the anode and cathode.

  18. Study on corrosion of metal materials in nitrate molten salts

    NASA Astrophysics Data System (ADS)

    Zhai, Wei; Yang, Bo; Li, Maodong; Li, Shiping; Xin, Mingliang; Zhang, Shuanghong; Huang, Guojia

    2017-01-01

    High temperature molten salts as a heat transfer heat storage medium has been more widely used in the field of concentrated solar thermal power generation. In the thermal heat storage system, metal material stability and performance at high temperatures are of one major limitation in increasing this operating temperature. In this paper, study on corrosion of 321H, 304, 316L, P91 metal materials in modified solar two molten salts. The corrosion kinetics of 304, 316L, 321H, P91 metal material in the modified solar two molten salts at 450°C, 500°C is also investigated. Under the same condition it was found that 304, 321H corroded at a rate of 40% less than P91. Spallation of corrosion products was observed on P91 steel, while no obvious observed on other kinds of stainless steel. Corrosion rates of 304, 321H, and 316L slowly increased with temperature. Oxidation mechanisms little varied with temperature. Corrosion products of metal materials observed at 450°C, 500°C were primarily Fe oxide and Fe, Cr oxide.

  19. DFT study of the interaction between DOTA chelator and competitive alkali metal ions.

    PubMed

    Frimpong, E; Skelton, A A; Honarparvar, B

    2017-09-01

    1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetracetic acid (DOTA) is an important chelator for radiolabeling of pharmaceuticals. The ability of alkali metals found in the body to complex with DOTA and compete with radio metal ions can alter the radiolabeling process. Non-covalent interactions between DOTA complexed with alkali metals Li + , Na + , K + and Rb + , are investigated with density functional theory using B3LYP and ωB97XD functionals. Conformational possibilities of DOTA were explored with a varying number of carboxylic pendant arms of DOTA in close proximity to the ions. It is found that the case in which four arms of DOTA are interacting with ions is more stable than other conformations. The objective of this study is to explore the electronic structure properties upon complexation of alkali metals Li + Na + , K + and Rb + with a DOTA chelator. Interaction energies, relaxation energies, entropies, Gibbs free energies and enthalpies show that the stability of DOTA, complexed with alkali metals decreases down the group of the periodic table. Implicit water solvation affects the complexation of DOTA-ions leading to decreases in the stability of the complexes. NBO analysis through the natural population charges and the second order perturbation theory, revealed a charge transfer between DOTA and alkali metals. Conceptual DFT-based properties such as HOMO/LUMO energies, ΔE HOMO-LUMO and chemical hardness and softness indicated a decrease in the chemical stability of DOTA-alkali metal complexes down the alkali metal series. This study serves as a guide to researchers in the field of organometallic chelators, particularly, radiopharmaceuticals in finding the efficient optimal match between chelators and various metal ions. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Is Electronegativity a Useful Descriptor for the "Pseudo-Alkali-Metal" NH4?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Whiteside, Alexander; Xantheas, Sotiris S.; Gutowski, Maciej S.

    2011-11-18

    Molecular ions in the form of "pseudo-atoms" are common structural motifs in chemistry, with properties that are transferrable between different compounds. We have determined the electronegativity of the "pseudo-alkali metal" ammonium (NH4) and evaluated its reliability as a descriptor in comparison to the electronegativities of the alkali metals. The computed properties of its binary complexes with astatine and of selected borohydrides confirm the similarity of NH4 to the alkali metal atoms, although the electronegativity of NH4 is relatively large in comparison to its cationic radius. We paid particular attention to the molecular properties of ammonium (angular anisotropy, geometric relaxation, andmore » reactivity), which can cause deviations from the behaviour expected of a conceptual "true alkali metal" with this electronegativity. These deviations allow for the discrimination of effects associated with the polyatomic nature of NH4.« less

  1. Tuning the electronic structure of graphene through alkali metal and halogen atom intercalation

    NASA Astrophysics Data System (ADS)

    Ahmad, Sohail; Miró, Pere; Audiffred, Martha; Heine, Thomas

    2018-04-01

    The deposition, intercalation and co-intercalation of heavy alkali metals and light halogens atoms in graphene mono- and bilayers have been studied using first principles density-functional calculations. Both the deposition and the intercalation of alkali metals gives rise to n-type doping due to the formation of M+-C- pairs. The co-intercalation of a 1:1 ratio of alkali metals and halogens derives into the formation of ionic pairs among the intercalated species, unaltering the electronic structure of the layered material.

  2. A review of the high temperature oxidation of uranium oxides in molten salts and in the solid state to form alkali metal uranates, and their composition and properties

    NASA Astrophysics Data System (ADS)

    Griffiths, Trevor R.; Volkovich, Vladimir A.

    An extensive review of the literature on the high temperature reactions (both in melts and in the solid state) of uranium oxides (UO 2, U 3O 8 and UO 3) resulting in the formation of insoluble alkali metal (Li to Cs) uranates is presented. Their uranate(VI) and uranate(V) compounds are examined, together with mixed and oxygen-deficient uranates. The reactions of uranium oxides with carbonates, oxides, per- and superoxides, chlorides, sulfates, nitrates and nitrites under both oxidising and non-oxidising conditions are critically examined and systematised, and the established compositions of a range of uranate(VI) and (V) compounds formed are discussed. Alkali metal uranates(VI) are examined in detail and their structural, physical, thermodynamic and spectroscopic properties considered. Chemical properties of alkali metal uranates(VI), including various methods for their reduction, are also reported. Errors in the current theoretical treatment of uranate(VI) spectra are identified and the need to develop routes for the preparation of single crystals is stressed.

  3. Alkali metal yttrium neo-pentoxide double alkoxide precursors to alkali metal yttrium oxide nanomaterials

    DOE PAGES

    Boyle, Timothy J.; Neville, Michael L.; Sears, Jeremiah Matthew; ...

    2016-03-15

    In this study, a series of alkali metal yttrium neo-pentoxide ([AY(ONep) 4]) compounds were developed as precursors to alkali yttrium oxide (AYO 2) nanomaterials. The reaction of yttrium amide ([Y(NR 2) 3] where R=Si(CH 3) 3) with four equivalents of H-ONep followed by addition of [A(NR 2)] (A=Li, Na, K) or A o (A o=Rb, Cs) led to the formation of a complex series of A nY(ONep) 3+n species, crystallographically identified as [Y 2Li 3(μ 3-ONep)(μ 3-HONep)(μ-ONep) 5(ONep) 3(HONep) 2] (1), [YNa 2(μ 3-ONep) 4(ONep)] 2 (2), {[Y 2K 3(μ 3-ONep) 3(μ-ONep) 4(ONep) 2(ηξ-tol) 2][Y 4K 2(μ 4-O)(μ 3-ONep) 8(ONep)more » 4]•η x-tol]} (3), [Y 4K 2(μ 4-O)(μ 3-ONep) 8(ONep) 4] (3a), [Y 2Rb 3(μ 4-ONep) 3(μ-ONep) 6] (4), and [Y 2Cs 4(μ 6-O)(μ 3-ONep) 6(μ 3-HONep) 2(ONep) 2(η x-tol) 4]•tol (5). Compounds 1–5 were investigated as single source precursors to AYOx nanomaterials following solvothermal routes (pyridine, 185 °C for 24h). The final products after thermal processing were found by powder X-ray diffraction experiments to be Y 2O 3 with variable sized particles based on transmission electron diffraction. Energy dispersive X-ray spectroscopy studies indicated that the heavier alkali metal species were present in the isolated nanomaterials.« less

  4. Upgrading of petroleum oil feedstocks using alkali metals and hydrocarbons

    DOEpatents

    Gordon, John Howard

    2014-09-09

    A method of upgrading an oil feedstock by removing heteroatoms and/or one or more heavy metals from the oil feedstock composition. This method reacts the oil feedstock with an alkali metal and an upgradant hydrocarbon. The alkali metal reacts with a portion of the heteroatoms and/or one or more heavy metals to form an inorganic phase separable from the organic oil feedstock material. The upgradant hydrocarbon bonds to the oil feedstock material and increases the number of carbon atoms in the product. This increase in the number of carbon atoms of the product increases the energy value of the resulting oil feedstock.

  5. Method of removal of heavy metal from molten salt in IFR fuel pyroprocessing

    DOEpatents

    Gay, E.C.

    1995-10-03

    An electrochemical method is described for separating heavy metal values from a radioactive molten salt including Li halide at temperatures of about 500 C. The method comprises positioning a solid Li--Cd alloy anode in the molten salt containing the heavy metal values, positioning a Cd-containing cathode or a solid cathode positioned above a catch crucible in the molten salt to recover the heavy metal values, establishing a voltage drop between the anode and the cathode to deposit material at the cathode to reduce the concentration of heavy metals in the salt, and controlling the deposition rate at the cathode by controlling the current between the anode and cathode. 3 figs.

  6. Highly reproducible alkali metal doping system for organic crystals through enhanced diffusion of alkali metal by secondary thermal activation.

    PubMed

    Lee, Jinho; Park, Chibeom; Song, Intek; Koo, Jin Young; Yoon, Taekyung; Kim, Jun Sung; Choi, Hee Cheul

    2018-05-16

    In this paper, we report an efficient alkali metal doping system for organic single crystals. Our system employs an enhanced diffusion method for the introduction of alkali metal into organic single crystals by controlling the sample temperature to induce secondary thermal activation. Using this system, we achieved intercalation of potassium into picene single crystals with closed packed crystal structures. Using optical microscopy and Raman spectroscopy, we confirmed that the resulting samples were uniformly doped and became K 2 picene single crystal, while only parts of the crystal are doped and transformed into K 2 picene without secondary thermal activation. Moreover, using a customized electrical measurement system, the insulator-to-semiconductor transition of picene single crystals upon doping was confirmed by in situ electrical conductivity and ex situ temperature-dependent resistivity measurements. X-ray diffraction studies showed that potassium atoms were intercalated between molecular layers of picene, and doped samples did not show any KH- nor KOH-related peaks, indicating that picene molecules are retained without structural decomposition. During recent decades, tremendous efforts have been exerted to develop high-performance organic semiconductors and superconductors, whereas as little attention has been devoted to doped organic crystals. Our method will enable efficient alkali metal doping of organic crystals and will be a resource for future systematic studies on the electrical property changes of these organic crystals upon doping.

  7. Process for carbonaceous material conversion and recovery of alkali metal catalyst constituents held by ion exchange sites in conversion residue

    DOEpatents

    Sharp, David W.

    1980-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered for the particles by contacting or washing them with an aqueous solution containing calcium or magnesium ions in an alkali metal recovery zone at a low temperature, preferably below about 249.degree. F. During the washing or leaching process, the calcium or magnesium ions displace alkali metal ions held by ion exchange sites in the particles thereby liberating the ions and producing an aqueous effluent containing alkali metal constituents. The aqueous effluent from the alkali metal recovery zone is then recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

  8. Is electronegativity a useful descriptor for the pseudo-alkali metal NH4?

    PubMed

    Whiteside, Alexander; Xantheas, Sotiris S; Gutowski, Maciej

    2011-11-18

    Molecular ions in the form of "pseudo-atoms" are common structural motifs in chemistry, with properties that are transferrable between different compounds. We have determined one such property--the electronegativity--for the "pseudo-alkali metal" ammonium (NH(4)), and evaluated its reliability as a descriptor versus the electronegativities of the alkali metals. The computed properties of ammonium's binary complexes with astatine and of selected borohydrides confirm the similarity of NH(4) to the alkali metal atoms, although the electronegativity of NH(4) is relatively large in comparison to its cationic radius. We have paid particular attention to the molecular properties of ammonium (angular anisotropy, geometric relaxation and reactivity), which can cause deviations from the behaviour expected of a conceptual "true alkali metal" with this electronegativity. These deviations allow for the discrimination of effects associated with the molecular nature of NH(4). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Observation of Raman self-focusing in an alkali-metal vapor cell

    NASA Astrophysics Data System (ADS)

    Proite, N. A.; Unks, B. E.; Green, J. T.; Yavuz, D. D.

    2008-02-01

    We report an experimental demonstration of Raman self-focusing and self-defocusing in a far-off resonant alkali-metal atomic system. The key idea is to drive a hyperfine transition in an alkali-metal atom to a maximally coherent state with two laser beams. In this regime, the two-photon detuning from the Raman resonance controls the nonlinear index of the medium.

  10. Removal of oxides from alkali metal melts by reductive titration to electrical resistance-change end points

    DOEpatents

    Tsang, Floris Y.

    1980-01-01

    Alkali metal oxides dissolved in alkali metal melts are reduced with soluble metals which are converted to insoluble oxides. The end points of the reduction is detected as an increase in electrical resistance across an alkali metal ion-conductive membrane interposed between the oxide-containing melt and a material capable of accepting the alkali metal ions from the membrane when a difference in electrical potential, of the appropriate polarity, is established across it. The resistance increase results from blocking of the membrane face by ions of the excess reductant metal, to which the membrane is essentially non-conductive.

  11. Compression-Driven Enhancement of Electronic Correlations in Simple Alkali Metals

    NASA Astrophysics Data System (ADS)

    Fabbris, Gilberto; Lim, Jinhyuk; Veiga, Larissa; Haskel, Daniel; Schilling, James

    2015-03-01

    Alkali metals are the best realization of the nearly free electron model. This scenario appears to change dramatically as the alkalis are subjected to extreme pressure, leading to unexpected properties such as the departure from metallic behavior in Li and Na, and the occurrence of remarkable low-symmetry crystal structures in all alkalis. Although the mechanism behind these phase transitions is currently under debate, these are believed to be electronically driven. In this study the high-pressure electronic and structural ground state of Rb and Cs was investigated through low temperature XANES and XRD measurements combined with ab initio calculations. The results indicate that the pressure-induced localization of the conduction band triggers a Peierls-like mechanism, inducing the low symmetry phases. This localization process is evident by the pressure-driven increase in the number of d electrons, which takes place through strong spd hybridization. These experimental results indicate that compression turns the heavy alkali metals into strongly correlated electron systems. Work at Argonne was supported by DOE No. DE-AC02-06CH11357. Research at Washington University was supported by NSF DMR-1104742 and CDAC/DOE/NNSA DE-FC52-08NA28554.

  12. SEPARATION OF METAL SALTS BY ADSORPTION

    DOEpatents

    Gruen, D.M.

    1959-01-20

    It has been found that certain metal salts, particularly the halides of iron, cobalt, nickel, and the actinide metals, arc readily absorbed on aluminum oxide, while certain other salts, particularly rare earth metal halides, are not so absorbed. Use is made of this discovery to separate uranium from the rare earths. The metal salts are first dissolved in a molten mixture of alkali metal nitrates, e.g., the eutectic mixture of lithium nitrate and potassium nitrate, and then the molten salt solution is contacted with alumina, either by slurrying or by passing the salt solution through an absorption tower. The process is particularly valuable for the separation of actinides from lanthanum-group rare earths.

  13. Molten metal containment vessel with rare earth oxysulfide protective coating thereon and method of making same

    DOEpatents

    Krikorian, Oscar H.; Curtis, Paul G.

    1992-01-01

    An improved molten metal containment vessel is disclosed in which wetting of the vessel's inner wall surfaces by molten metal is inhibited by coating at least the inner surfaces of the containment vessel with one or more rare earth oxysulfide or rare earth sulfide compounds to inhibit wetting and or adherence by the molten metal to the surfaces of the containment vessel.

  14. Advances in high temperature components for AMTEC (alkali metal thermal-to-electric converter)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Williams, R.M.; Jeffries-Nakamura, B.; Underwood, M.L.

    1991-12-31

    Long lifetimes are required for AMTEC (or sodium heat engine) components for aerospace and terrestrial applications, and the high heat input temperature as well as the alkali metal liquid and vapor environment places unusual demands on the materials used to construct AMTEC devices. In addition, it is important to maximize device efficiency and power density, while maintaining a long life capability. In addition to the electrode, which must provide both efficient electrode kinetics, transport of the alkali metal, and low electrical resistance, other high temperature components of the cell face equally demanding requirements. The beta{double_prime} alumina solid electrolyte (BASE), themore » seal between the BASE ceramic and its metallic transition to the hot alkali metal (liquid or vapor) source, and metallic components of the device are exposed to hot liquid alkali metal. Modification of AMTEC components may also be useful in optimizing the device for particular operating conditions. In particular, a potassium AMTEC may be expected to operate more efficiently at lower temperatures.« less

  15. Advances in high temperature components for AMTEC (alkali metal thermal-to-electric converter)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Williams, R.M.; Jeffries-Nakamura, B.; Underwood, M.L.

    1991-01-01

    Long lifetimes are required for AMTEC (or sodium heat engine) components for aerospace and terrestrial applications, and the high heat input temperature as well as the alkali metal liquid and vapor environment places unusual demands on the materials used to construct AMTEC devices. In addition, it is important to maximize device efficiency and power density, while maintaining a long life capability. In addition to the electrode, which must provide both efficient electrode kinetics, transport of the alkali metal, and low electrical resistance, other high temperature components of the cell face equally demanding requirements. The beta{double prime} alumina solid electrolyte (BASE),more » the seal between the BASE ceramic and its metallic transition to the hot alkali metal (liquid or vapor) source, and metallic components of the device are exposed to hot liquid alkali metal. Modification of AMTEC components may also be useful in optimizing the device for particular operating conditions. In particular, a potassium AMTEC may be expected to operate more efficiently at lower temperatures.« less

  16. Method for determining molten metal pool level in twin-belt continuous casting machines

    DOEpatents

    Kaiser, Timothy D.; Daniel, Sabah S.; Dykes, Charles D.

    1989-03-21

    A method for determining level of molten metal in the input of a continuous metal casting machine having at least one endless, flexible, revolving casting belt with a surface which engages the molten metal to be cast and a reverse, cooled surface along which is directed high velocity liquid coolant includes the steps of predetermining the desired range of positions of the molten metal pool and positioning at least seven heat-sensing transducers in bearing contact with the moving reverse belt surface and spaced in upstream-downstream relationship relative to belt travel spanning the desired pool levels. A predetermined temperature threshold is set, somewhat above coolant temperature and the output signals of the transducer sensors are scanned regarding their output signals indicative of temperatures of the moving reverse belt surface. Position of the molten pool is determined using temperature interpolation between any successive pair of upstream-downstream spaced sensors, which follows confirmation that two succeeding downstream sensors are at temperature levels exceeding threshold temperature. The method accordingly provides high resolution for determining pool position, and verifies the determined position by utilizing full-strength signals from two succeeding downstream sensors. In addition, dual sensors are used at each position spanning the desired range of molten metal pool levels to provide redundancy, wherein only the higher temperature of each pair of sensors at a station is utilized.

  17. Wetting of a Charged Surface of Glassy Carbon by Molten Alkali-Metal Chlorides

    NASA Astrophysics Data System (ADS)

    Stepanov, V. P.

    2018-03-01

    Values of the contact angle of wetting of a surface of glassy carbon by molten chlorides of lithium, sodium, potassium, and cesium are measured by the meniscus weight method to determine the common factors of wettability of solid surfaces by ionic melts upon a change in the salt phase composition and a jump in electric potential. It is found that with a potential shift in the positive direction the shape of the curve of the contact angle's dependence on the potential varies upon substitution of one salt by another: the angle of wetting shrinks monotonously in lithium chloride but remains constant in molten cesium chloride. This phenomenon is explained by the hypothesis that the nature of the halide anion adsorption on the positively charged surface of an electrode is chemical and not electrostatic. It is shown that the adsorption process is accompanied by charge transfer through the interface, with covalent bonding between the adsorbent and adsorbate.

  18. Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

    DOEpatents

    Doeff, Marca M.; Peng, Marcus Y.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard C.

    1996-01-01

    An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell.

  19. Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

    DOEpatents

    Doeff, M.M.; Peng, M.Y.; Ma, Y.; Visco, S.J.; DeJonghe, L.C.

    1996-09-24

    An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M{sub x}Z{sub y}Mn{sub (1{minus}y)}O{sub 2}, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell. 11 figs.

  20. Alkali metal-refractory metal biphase electrode for AMTEC

    NASA Technical Reports Server (NTRS)

    Williams, Roger M. (Inventor); Bankston, Clyde P. (Inventor); Cole, Terry (Inventor); Khanna, Satish K. (Inventor); Jeffries-Nakamura, Barbara (Inventor); Wheeler, Bob L. (Inventor)

    1989-01-01

    An electrode having increased output with slower degradation is formed of a film applied to a beta-alumina solid electrolyte (BASE). The film comprises a refractory first metal M.sup.1 such as a platinum group metal, suitably platinum or rhodium, capable of forming a liquid or a strong surface adsorption phase with sodium at the operating temperature of an alkali metal thermoelectric converter (AMTEC) and a second refractory metal insoluble in sodium or the NaM.sup.1 liquid phase such as a Group IVB, VB or VIB metal, suitably tungsten, molybdenum, tantalum or niobium. The liquid phase or surface film provides fast transport through the electrode while the insoluble refractory metal provides a structural matrix for the electrode during operation. A trilayer structure that is stable and not subject to deadhesion comprises a first, thin layer of tungsten, an intermediate co-deposited layer of tungsten-platinum and a thin surface layer of platinum.

  1. Behavior of toxic metals and radionuclides during molten salt oxidation of chlorinated plastics.

    PubMed

    Yang, Hee-Chul; Cho, Yong-Jun; Eun, Hee-Chul; Yoo, Jae-Hyung; Kim, Joon-Hyung

    2004-01-01

    Molten salt oxidation is one of the promising alternatives to incineration for chlorinated organics without the emission of chlorinated organic pollutants. This study investigated the behavior of three hazardous metals (Cd, Pb, and Cr) and four radioactive metal surrogates (Cs, Ce, Gd, and Sm) in the molten Na2CO3 oxidation reactor during the destruction of PVC plastics. In the tested temperature ranges (1143 1223K) and NaCl content (0-10%), the impact of temperature on the retention of cadmium and lead in the molten salt reactor was very small, but that of the NaCl content for their retention was relatively higher. The influence of NaCl accumulation was, however, proven to be practically negligible due to the low-temperature operating characteristics of the molten salt oxidation system. Neither temperature increase nor chlorine accumulation in the MSO reactor reduced the retention of Cr, Ce, Gd, and Sm. Over 99.98% of these metals remained in the reactor. The influence of the temperature on the cesium behavior is relatively large for a chlorine addition, however, over 99.7% of cesium remained in the reactor throughout the entire test. The experimental metal entrainment rate and the entrained metal particle size distribution agree well with the theoretical equilibrium metal distributions.

  2. Method for producing hydrocarbon fuels and fuel gas from heavy polynuclear hydrocarbons by the use of molten metal halide catalysts

    DOEpatents

    Gorin, Everett

    1979-01-01

    In a process for hydrocracking heavy polynuclear carbonaceous feedstocks to produce lighter hydrocarbon fuels by contacting the heavy feedstocks with hydrogen in the presence of a molten metal halide catalyst in a hydrocracking zone, thereafter separating at least a major portion of the lighter hydrocarbon fuels from the spent molten metal halide and thereafter regenerating the spent molten metal halide by incinerating the spent molten metal halide by combustion of carbon and sulfur compounds in the spent molten metal halide in an incineration zone, the improvement comprising: (a) contacting the heavy feedstocks and hydrogen in the presence of the molten metal halide in the hydrocracking zone at reaction conditions effective to convert from about 60 to about 90 weight percent of the feedstock to lighter hydrocarbon fuels; (b) separating at least a major portion of the lighter hydrocarbon fuels from the spent molten metal halide; (c) contacting the spent molten metal halide with oxygen in a liquid phase gasification zone at a temperature and pressure sufficient to vaporize from about 25 to about 75 weight percent of the spent metal halide, the oxygen being introduced in an amount sufficient to remove from about 60 to about 90 weight percent of the carbon contained in the spent molten metal halide to produce a fuel gas and regenerated metal halide; and (d) incinerating the spent molten metal halide by combusting carbon and sulfur compounds contained therein.

  3. Fragment structure from vapor explosions during the impact of molten metal droplets into a liquid pool

    NASA Astrophysics Data System (ADS)

    Kouraytem, Nadia; Li, Er Qiang; Vakarelski, Ivan Uriev; Thoroddsen, Sigurdur

    2015-11-01

    High-speed video imaging is used in order to look at the impact of a molten metal drop falling into a liquid pool. The interaction regimes are three: film boiling, nucleate boiling or vapor explosion. Following the vapor explosion, the metal fragments and different textures are observed. It was seen that, using a tin alloy, a porous structure results whereas using a distinctive eutectic metal, Field's metal, micro beads are formed. Different parameters such as the metal type, molten metal temperature, pool surface tension and pool boiling temperature have been altered in order to assess the role they play on the explosion dynamics and the molten metal's by product.

  4. Heat capacity of molten halides.

    PubMed

    Redkin, Alexander A; Zaikov, Yurii P; Korzun, Iraida V; Reznitskikh, Olga G; Yaroslavtseva, Tatiana V; Kumkov, Sergey I

    2015-01-15

    The heat capacities of molten salts are very important for their practical use. Experimental investigation of this property is challenging because of the high temperatures involved and the corrosive nature of these materials. It is preferable to combine experimental investigations with empirical relationships, which allows for the evaluation of the heat capacity of molten salt mixtures. The isobaric molar heat capacities of all molten alkali and alkaline-earth halides were found to be constant for each group of salts. The value depends on the number of atoms in the salt, and the molar heat capacity per atom is constant for all molten halide salts with the exception of the lithium halides. The molar heat capacities of molten halides do not change when the anions are changed.

  5. METHOD OF PRODUCING DENSE CONSOLIDATED METALLIC REGULUS

    DOEpatents

    Magel, T.T.

    1959-08-11

    A methcd is presented for reducing dense metal compositions while simultaneously separating impurities from the reduced dense metal and casting the reduced parified dense metal, such as uranium, into well consolidated metal ingots. The reduction is accomplished by heating the dense metallic salt in the presence of a reducing agent, such as an alkali metal or alkaline earth metal in a bomb type reacting chamber, while applying centrifugal force on the reacting materials. Separation of the metal from the impurities is accomplished essentially by the incorporation of a constricted passageway at the vertex of a conical reacting chamber which is in direct communication with a collecting chamber. When a centrifugal force is applled to the molten metal and slag from the reduction in a direction collinear with the axis of the constricted passage, the dense molten metal is forced therethrough while the less dense slag is retained within the reaction chamber, resulting in a simultaneous separation of the reduced molten metal from the slag and a compacting of the reduced metal in a homogeneous mass.

  6. Method for producing hydrocarbon fuels from heavy polynuclear hydrocarbons by use of molten metal halide catalyst

    DOEpatents

    Gorin, Everett

    1979-01-01

    In a process for hydrocracking heavy polynuclear carbonaceous feedstocks to produce lighter hydrocarbon fuels by contacting the heavy feedstocks with hydrogen in the presence of a molten metal halide catalyst, thereafter separating at least a substantial portion of the carbonaceous material associated with the reaction mixture from the spent molten metal halide and thereafter regenerating the metal halide catalyst, an improvement comprising contacting the spent molten metal halide catalyst after removal of a major portion of the carbonaceous material therefrom with an additional quantity of hydrogen is disclosed.

  7. Hall Determination of Atomic Radii of Alkali Metals

    ERIC Educational Resources Information Center

    Houari, Ahmed

    2008-01-01

    I will propose here an alternative method for determining atomic radii of alkali metals based on the Hall measurements of their free electron densities and the knowledge of their crystal structure. (Contains 2 figures.)

  8. Method for hydrocracking a heavy polynuclear hydrocarbonaceous feedstock in the presence of a molten metal halide catalyst

    DOEpatents

    Gorin, Everett

    1981-01-01

    A method for hydrocracking a heavy polynuclear hydrocarbonaceous feedstock to produce lighter hydrocarbon fuels by contacting the feedstock with hydrogen in the presence of a molten metal halide catalyst, the method comprising: mixing the feedstock with a heavy naphtha fraction which has an initial boiling point from about 100.degree. to about 160.degree. C. with a boiling point difference between the initial boiling point and the final boiling point of no more than about 50.degree. C. to produce a mixture; thereafter contacting the mixture with partially spent molten metal halide and hydrogen under temperature and pressure conditions so that the temperature is near the critical temperature of the heavy naphtha fraction; separating at least a portion of the heavy naphtha fraction and lighter hydrocarbon fuels from the partially spent molten metal halide, unreacted feedstock and reaction products; thereafter contacting the partially spent molten metal halide, unreacted feedstock and reaction products with hydrogen and fresh molten metal halide in a hydrocracking zone to produce additional lighter hydrocarbon fuels and separating at least a major portion of the lighter hydrocarbon fuels from the spent molten metal halide.

  9. Controlled temperature expansion in oxygen production by molten alkali metal salts

    DOEpatents

    Erickson, Donald C.

    1985-06-04

    A continuous process is set forth for the production of oxygen from an oxygen containing gas stream, such as air, by contacting a feed gas stream with a molten solution of an oxygen acceptor to oxidize the acceptor and cyclically regenerating the oxidized acceptor by releasing oxygen from the acceptor wherein the oxygen-depleted gas stream from the contact zone is treated sequentially to temperature reduction by heat exchange against the feed stream so as to condense out entrained oxygen acceptor for recycle to the process, combustion of the gas stream with fuel to elevate its temperature and expansion of the combusted high temperature gas stream in a turbine to recover power.

  10. Controlled temperature expansion in oxygen production by molten alkali metal salts

    DOEpatents

    Erickson, D.C.

    1985-06-04

    A continuous process is set forth for the production of oxygen from an oxygen containing gas stream, such as air, by contacting a feed gas stream with a molten solution of an oxygen acceptor to oxidize the acceptor and cyclically regenerating the oxidized acceptor by releasing oxygen from the acceptor wherein the oxygen-depleted gas stream from the contact zone is treated sequentially to temperature reduction by heat exchange against the feed stream so as to condense out entrained oxygen acceptor for recycle to the process, combustion of the gas stream with fuel to elevate its temperature and expansion of the combusted high temperature gas stream in a turbine to recover power. 1 fig.

  11. Process for preparing higher oxides of the alkali and alkaline earth metals

    NASA Technical Reports Server (NTRS)

    Sadhukhan, P.; Bell, A. (Inventor)

    1978-01-01

    High purity inorganic higher oxides of the alkali and alkaline earth metals are prepared by subjecting the hydroxide of the alkali and alkaline earth metal to a radio frequency discharge sustained in oxygen. The process is particulary adaptable to the production of high purity potassium superoxide by subjecting potassium hydroxide to glow discharge sustained in oxygen under the pressure of about 0.75 to 1.00 torr.

  12. Conjugate heat transfer analysis of an ultrasonic molten metal treatment system

    NASA Astrophysics Data System (ADS)

    Zhu, Youli; Bian, Feilong; Wang, Yanli; Zhao, Qian

    2014-09-01

    In piezoceramic ultrasonic devices, the piezoceramic stacks may fail permanently or function improperly if their working temperatures overstep the Curie temperature of the piezoceramic material. While the end of the horn usually serves near the melting point of the molten metal and is enclosed in an airtight chamber, so that it is difficult to experimentally measure the temperature of the transducer and its variation with time, which bring heavy difficulty to the design of the ultrasonic molten metal treatment system. To find a way out, conjugate heat transfer analysis of an ultrasonic molten metal treatment system is performed with coupled fluid and heat transfer finite element method. In modeling of the system, the RNG model and the SIMPLE algorithm are adopted for turbulence and nonlinear coupling between the momentum equation and the energy equation. Forced air cooling as well as natural air cooling is analyzed to compare the difference of temperature evolution. Numerical results show that, after about 350 s of working time, temperatures in the surface of the ceramic stacks in forced air cooling drop about 7 K compared with that in natural cooling. At 240 s, The molten metal surface emits heat radiation with a maximum rate of about 19 036 W/m2, while the heat insulation disc absorbs heat radiation at a maximum rate of about 7922 W/m2, which indicates the effectiveness of heat insulation of the asbestos pad. Transient heat transfer film coefficient and its distribution, which are difficult to be measured experimentally are also obtained through numerical simulation. At 240 s, the heat transfer film coefficient in the surface of the transducer ranges from -17.86 to 20.17 W/(m2 · K). Compared with the trial and error method based on the test, the proposed research provides a more effective way in the design and analysis of the temperature control of the molten metal treatment system.

  13. Molten Metal Treatment by Salt Fluxing with Low Environmental Emissions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yogeshwar Sahai

    2007-07-31

    Abstract: Chlorine gas is traditionally used for fluxing of aluminum melt for removal of alkali and alkaline earth elements. However this results in undesirable emissions of particulate matter and gases such as HCl and chlorine, which are often at unacceptable levels. Additionally, chlorine gas is highly toxic and its handling, storage, and use pose risks to employees and the local community. Holding of even minimal amounts of chlorine necessitates extensive training for all plant employees. Fugitive emissions from chlorine usage within the plant cause accelerated corrosion of plant equipment. The Secondary Aluminum Maximum Achievable Control Technology (MACT) under the Cleanmore » Air Act, finalized in March 2000 has set very tough new limits on particulate matter (PM) and total hydrogen chloride emissions from aluminum melting and holding furnaces. These limits are 0.4 and 0.1 lbs per ton of aluminum for hydrogen chloride and particulate emissions, respectively. Assuming new technologies for meeting these limits can be found, additional requirements under the Clean Air Act (Prevention of Significant Deterioration and New Source Review) trigger Best Available Control Technology (BACT) for new sources with annual emissions (net emissions not expressed per ton of production) over specified amounts. BACT currently is lime coated bag-houses for control of particulate and HCl emissions. These controls are expensive, difficult to operate and maintain, and result in reduced American competitiveness in the global economy. Solid salt fluxing is emerging as a viable option for the replacement of chlorine gas fluxing, provided emissions can be consistently maintained below the required levels. This project was a cooperative effort between the Ohio State University and Alcoa to investigate and optimize the effects of solid chloride flux addition in molten metal for alkali impurity and non-metallic inclusion removal minimizing dust and toxic emissions and maximizing energy

  14. Stabilized Alkali-Metal Ultraviolet-Band-Pass Filters

    NASA Technical Reports Server (NTRS)

    Mardesich, Nick; Fraschetti, George A.; Mccann, Timothy; Mayall, Sherwood D.; Dunn, Donald E.; Trauger, John T.

    1995-01-01

    Layers of bismuth 5 to 10 angstrom thick incorporated into alkali-metal ultraviolet-band-pass optical filters by use of advanced fabrication techniques. In new filters layer of bismuth helps to reduce surface migration of sodium. Sodium layer made more stable and decreased tendency to form pinholes by migration.

  15. Roles of Cationic and Elemental Calcium in the Electro-Reduction of Solid Metal Oxides in Molten Calcium Chloride

    NASA Astrophysics Data System (ADS)

    Qiu, Guohong; Jiang, Kai; Ma, Meng; Wang, Dihua; Jin, Xianbo; Chen, George Z.

    2007-06-01

    Previous work, mainly from this research group, is re-visited on electrochemical reduction of solid metal oxides, in the form of compacted powder, in molten CaCl2, aiming at further understanding of the roles of cationic and elemental calcium. The discussion focuses on six aspects: 1.) debate on two mechanisms proposed in the literature, i. e. electro-metallothermic reduction and electro-reduction (or electro-deoxidation), for the electrolytic removal of oxygen from solid metals or metal oxides in molten CaCl2; 2.) novel metallic cavity working electrodes for electrochemical investigations of compacted metal oxide powders in high temperature molten salts assisted by a quartz sealed Ag/AgCl reference electrode (650 ºC- 950 ºC); 3.) influence of elemental calcium on the background current observed during electrolysis of solid metal oxides in molten CaCl2; 4.) electrochemical insertion/ inclusion of cationic calcium into solid metal oxides; 5.) typical features of cyclic voltammetry and chronoamperometry (potentiostatic electrolysis) of metal oxide powders in molten CaCl2; and 6.) some kinetic considerations on the electrolytic removal of oxygen.

  16. Alkali Metal Heat Pipe Life Issues

    NASA Technical Reports Server (NTRS)

    Reid, Robert S.

    2004-01-01

    One approach to space fission power system design is predicated on the use of alkali metal heat pipes, either as radiator elements, thermal management components, or as part of the core primary heat-transfer system. This synopsis characterizes long-life core heat pipes. References are included where more detailed information can be found. Specifics shown here are for demonstrational purposes and do not necessarily reflect current Project Prometheus point designs.

  17. Apparatus and Method for Increasing the Diameter of Metal Alloy Wires Within a Molten Metal Pool

    DOEpatents

    Hartman, Alan D.; Argetsinger, Edward R.; Hansen, Jeffrey S.; Paige, Jack I.; King, Paul E.; Turner, Paul C.

    2002-01-29

    In a dip forming process the core material to be coated is introduced directly into a source block of coating material eliminating the need for a bushing entrance component. The process containment vessel or crucible is heated so that only a portion of the coating material becomes molten, leaving a solid portion of material as the entrance port of, and seal around, the core material. The crucible can contain molten and solid metals and is especially useful when coating core material with reactive metals. The source block of coating material has been machined to include a close tolerance hole of a size and shape to closely fit the core material. The core material moves first through the solid portion of the source block of coating material where the close tolerance hole has been machined, then through a solid/molten interface, and finally through the molten phase where the diameter of the core material is increased. The crucible may or may not require water-cooling depending upon the type of material used in crucible construction. The system may operate under vacuum, partial vacuum, atmospheric pressure, or positive pressure depending upon the type of source material being used.

  18. Apparatus and method for increasing the diameter of metal alloy wires within a molten metal pool

    DOEpatents

    Hartman, Alan D.; Argetsinger, Edward R.; Hansen, Jeffrey S.; Paige, Jack I.; King, Paul E.; Turner, Paul C.

    2002-01-29

    In a dip forming process the core material to be coated is introduced directly into a source block of coating material eliminating the need for a bushing entrance component. The process containment vessel or crucible is heated so that only a portion of the coating material becomes molten, leaving a solid portion of material as the entrance port of, and seal around, the core material. The crucible can contain molten and solid metals and is especially useful when coating core material with reactive metals. The source block of coating material has been machined to include a close tolerance hole of a size and shape to closely fit the core material. The core material moves first through the solid portion of the source block of coating material where the close tolerance hole has been machined, then through a solid/molten interface, and finally through the molten phase where the diameter of the core material is increased. The crucible may or may not require water-cooling depending upon the type of material used in crucible construction. The system may operate under vacuum, partial vacuum, atmospheric pressure, or positive pressure depending upon the type of source material being used.

  19. Method for intercalating alkali metal ions into carbon electrodes

    DOEpatents

    Doeff, Marca M.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard

    1995-01-01

    A low cost, relatively flexible, carbon electrode for use in a secondary battery is described. A method is provided for producing same, including intercalating alkali metal salts such as sodium and lithium into carbon.

  20. Method for intercalating alkali metal ions into carbon electrodes

    DOEpatents

    Doeff, M.M.; Ma, Y.; Visco, S.J.; DeJonghe, L.

    1995-08-22

    A low cost, relatively flexible, carbon electrode for use in a secondary battery is described. A method is provided for producing same, including intercalating alkali metal salts such as sodium and lithium into carbon.

  1. A simple model for metal cation-phosphate interactions in nucleic acids in the gas phase: alkali metal cations and trimethyl phosphate.

    PubMed

    Ruan, Chunhai; Huang, Hai; Rodgers, M T

    2008-02-01

    Threshold collision-induced dissociation techniques are employed to determine the bond dissociation energies (BDEs) of complexes of alkali metal cations to trimethyl phosphate, TMP. Endothermic loss of the intact TMP ligand is the only dissociation pathway observed for all complexes. Theoretical calculations at the B3LYP/6-31G* level of theory are used to determine the structures, vibrational frequencies, and rotational constants of neutral TMP and the M+(TMP) complexes. Theoretical BDEs are determined from single point energy calculations at the B3LYP/6-311+G(2d,2p) level using the B3LYP/6-31G* optimized geometries. The agreement between theory and experiment is reasonably good for all complexes except Li+(TMP). The absolute M+-(TMP) BDEs are found to decrease monotonically as the size of the alkali metal cation increases. No activated dissociation was observed for alkali metal cation binding to TMP. The binding of alkali metal cations to TMP is compared with that to acetone and methanol.

  2. Ion conducting polymers and polymer blends for alkali metal ion batteries

    DOEpatents

    DeSimone, Joseph M.; Pandya, Ashish; Wong, Dominica; Vitale, Alessandra

    2017-08-29

    Electrolyte compositions for batteries such as lithium ion and lithium air batteries are described. In some embodiments the compositions are liquid compositions comprising (a) a homogeneous solvent system, said solvent system comprising a perfluropolyether (PFPE) and polyethylene oxide (PEO); and (b) an alkali metal salt dissolved in said solvent system. In other embodiments the compositions are solid electrolyte compositions comprising: (a) a solid polymer, said polymer comprising a crosslinked product of a crosslinkable perfluropolyether (PFPE) and a crosslinkable polyethylene oxide (PEO); and (b) an alkali metal ion salt dissolved in said polymer. Batteries containing such compositions as electrolytes are also described.

  3. 30 CFR 57.15007 - Protective equipment or clothing for welding, cutting, or working with molten metal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protective equipment or clothing for welding... equipment or clothing for welding, cutting, or working with molten metal. Protective clothing or equipment and face shields or goggles shall be worn when welding, cutting, or working with molten metal. ...

  4. 30 CFR 57.15007 - Protective equipment or clothing for welding, cutting, or working with molten metal.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Protective equipment or clothing for welding... equipment or clothing for welding, cutting, or working with molten metal. Protective clothing or equipment and face shields or goggles shall be worn when welding, cutting, or working with molten metal. ...

  5. 30 CFR 57.15007 - Protective equipment or clothing for welding, cutting, or working with molten metal.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Protective equipment or clothing for welding... equipment or clothing for welding, cutting, or working with molten metal. Protective clothing or equipment and face shields or goggles shall be worn when welding, cutting, or working with molten metal. ...

  6. 30 CFR 57.15007 - Protective equipment or clothing for welding, cutting, or working with molten metal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Protective equipment or clothing for welding... equipment or clothing for welding, cutting, or working with molten metal. Protective clothing or equipment and face shields or goggles shall be worn when welding, cutting, or working with molten metal. ...

  7. 30 CFR 57.15007 - Protective equipment or clothing for welding, cutting, or working with molten metal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Protective equipment or clothing for welding... equipment or clothing for welding, cutting, or working with molten metal. Protective clothing or equipment and face shields or goggles shall be worn when welding, cutting, or working with molten metal. ...

  8. Apparatus for efficient sidewall containment of molten metal with horizontal alternating magnetic fields utilizing low reluctance rims

    DOEpatents

    Praeg, Walter F.

    1999-01-01

    A method and apparatus for casting sheets of metal from molten metal. The apparatus includes a containment structure having an open side, a horizontal alternating magnetic field generating structure and rollers including low reluctance rim structures. The magnetic field and the rollers help contain the molten metal from leaking out of the containment structure.

  9. Apparatus for efficient sidewall containment of molten metal with horizontal alternating magnetic fields utilizing a ferromagnetic dam

    DOEpatents

    Praeg, Walter F.

    1997-01-01

    An apparatus for casting sheets of metal from molten metal. The apparatus includes a containment structure having an open side, a horizontal alternating magnetic field generating structure and a ferromagnetic dam. The magnetic field and the ferromagnetic dam contain the molten metal from leaking out side portions of the open side of the containment structure.

  10. In situ formation of coal gasification catalysts from low cost alkali metal salts

    DOEpatents

    Wood, Bernard J.; Brittain, Robert D.; Sancier, Kenneth M.

    1985-01-01

    A carbonaceous material, such as crushed coal, is admixed or impregnated with an inexpensive alkali metal compound, such as sodium chloride, and then pretreated with a stream containing steam at a temperature of 350.degree. to 650.degree. C. to enhance the catalytic activity of the mixture in a subsequent gasification of the mixture. The treatment may result in the transformation of the alkali metal compound into another, more catalytically active, form.

  11. Observations of impact-induced molten metal-silicate partitioning

    NASA Technical Reports Server (NTRS)

    Rowan, Linda R.; Ahrens, Thomas J.

    1994-01-01

    Observations of molten mid-ocean ridge basalt (MORB)-molybdenum (Mo) interactions produced by shock experiments provide insight into impact and differentiation processes involving metal-silicate partitioning. Analysis of fragments recovered from experiments (achieving MORB liquid shock pressures from 0.8 to 6 GPa) revealed significant changes in the composition of the MORB and Mo due to reaction of the silicate and metal liquids on a short time scale (less than 13 s). The FeO concentration of the shocked liquid decreases systematically with increasing pressure. In fact, the most highly shocked liquid (6 GPa) contains only 0.1 wt% FeO compared to an initial concentration of 9 wt% in the MORB. We infer from the presence of micrometer-sized Fe-, Si- and Mo-rich metallic spheres in the shocked glass that the Fe and Si oxides in the MORB were reduced in an estimated oxygen fugacity of 10(exp -17) bar and subsequently alloyed with the Mo. The in-situ reduction of FeO in the shocked molten basalt implies that shock-induced reduction of impact melt should be considered a viable mechanism for the formation of metallic phases. Similar metallic phases may form during impact accretion of planets and in impacted material found on the lunar surface and near terrestrial impact craters. In particular, the minute, isolated Fe particles found in lunar soils may have formed by such a process. Furthermore, the metallic spheres within the shocked glass have a globular texture similar to the textures of metallic spheroids from lunar samples and the estimated, slow cooling rate of less than or equal to 140 C/s for our spheres is consistent with the interpretation that the lunar spheroids formed by slow cooling within a melted target.

  12. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gordon, John Howard; Alvare, Javier

    Alkali metals and sulfur may be recovered from alkali monosulfide and polysulfides in an electrolytic process that utilizes an electrolytic cell having an alkali ion conductive membrane. An anolyte solution includes an alkali monosulfide, an alkali polysulfide, or a mixture thereof and a solvent that dissolves elemental sulfur. A catholyte includes molten alkali metal. Applying an electric current oxidizes sulfide and polysulfide in the anolyte compartment, causes alkali metal ions to pass through the alkali ion conductive membrane to the catholyte compartment, and reduces the alkali metal ions in the catholyte compartment. Liquid sulfur separates from the anolyte solution andmore » may be recovered. The electrolytic cell is operated at a temperature where the formed alkali metal and sulfur are molten.« less

  13. Apparatus for efficient sidewall containment of molten metal with horizontal alternating magnetic fields utilizing a ferromagnetic dam

    DOEpatents

    Praeg, W.F.

    1997-02-11

    An apparatus is disclosed for casting sheets of metal from molten metal. The apparatus includes a containment structure having an open side, a horizontal alternating magnetic field generating structure and a ferromagnetic dam. The magnetic field and the ferromagnetic dam contain the molten metal from leaking out side portions of the open side of the containment structure. 25 figs.

  14. Pump for molten metal or other fluid

    DOEpatents

    Horton, James A.; Brown, Donald L.

    1994-01-01

    A pump having no moving parts which can be used to pump high temperature molten metal or other fluids in a vacuum or low pressure environment, and a method for pumping such fluids. The pump combines elements of a bubble pump with a trap which isolates the vacuum or low pressure region from the gas used to create the bubbles. When used in a vacuum the trap prevents the pumping gas from escaping into the isolated region and thereby reducing the quality of the vacuum. The pump includes a channel in which a pumping gas is forced under pressure into a cavity where bubbles are formed. The cavity is in contact with a reservoir which contains the molten metal or other fluid which is to be pumped. The bubbles rise up into a column (or pump tube) carrying the fluid with them. At the top of the column is located a deflector which causes the bubbles to burst and the drops of pumped fluid to fall into a trap. The fluid accumulates in the trap, eventually forcing its way to an outlet. A roughing pump can be used to withdraw the pumping gas from the top of the column and assist with maintaining the vacuum or low pressure environment.

  15. Device and method for upgrading petroleum feedstocks and petroleum refinery streams using an alkali metal conductive membrane

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gordon, John Howard; Alvare, Javier

    A reactor has two chambers, namely an oil feedstock chamber and a source chamber. An ion separator separates the oil feedstock chamber from the source chamber, wherein the ion separator allows alkali metal ions to pass from the source chamber, through the ion separator, and into the oil feedstock chamber. A cathode is at least partially housed within the oil feedstock chamber and an anode is at least partially housed within the source chamber. A quantity of an oil feedstock is within the oil feedstock chamber, the oil feedstock comprising at least one carbon atom and a heteroatom and/or onemore » or more heavy metals, the oil feedstock further comprising naphthenic acid. When the alkali metal ion enters the oil feedstock chamber, the alkali metal reacts with the heteroatom, the heavy metals and/or the naphthenic acid, wherein the reaction with the alkali metal forms inorganic products.« less

  16. IUPAC-NIST Solubility Data Series. 75. Nonmetals in Liquid Alkali Metals

    NASA Astrophysics Data System (ADS)

    Borgstedt, Hans Ulrich; Guminski, Cezary; Borgstedt, Hans Ulrich; Guminski, Cezary

    2001-07-01

    Liquid alkali metals have several physical properties which favor their use in a number of important applications. For example, their large liquidus temperature range and their excellent heat transfer properties are important for use as heat transfer media. They are used in large nuclear reactors in which hundreds of tons of sodium are circulating, and in small parts of engines for cooling of valves. Since these metals are among the most electropositive elements, several of them (Li, Na) can be used in high specific capacity and high energy density batteries at moderately elevated temperatures. The compatibility of metallic constructional materials which are used to contain the liquid metals is strongly influenced by nonmetals present in the liquids. The physical properties of the liquid metals are also influenced by dissolved substances. Several nonmetals dissolved in alkali metals are able to form ternary compounds with components of the constructional materials. Thus, corrosion and compatibility studies have been accompanied by extensive chemical work related to the solutions of non-metallic substances in liquid alkali metals. All available solubility data of nonmetallic elements and some of their compounds in the five liquid alkali metal solvents (Li, Na, K, Rb, and Cs) are collected and compiled. Original publications with reliable data and information on the methods used to generate them are reported in individual Compilations. When numerical data are not given in a publication, the data are often read out from figures and converted into numerical data by the compilers. The precision of this procedure is indicated in the Compilations under Estimated Error. Evaluated solubility data are tabulated at the end of the Critical Evaluations: if there is agreement of at least two independent studies within the experimental error, the solubility values are assigned to the "recommended" category. Values are assigned as "tentative," if only one reliable result was

  17. Investigation of Anti-Relaxation Coatings for Alkali-Metal Vapor Cells using Surface Science Techniques

    DTIC Science & Technology

    2011-02-01

    worldwide. Lawrence Berkeley National Laboratory Peer Reviewed Title: Investigation of anti-Relaxation coatings for alkali-metal vapor cells using ...2010 Abstract: Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to...preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an

  18. Joule-Heated Molten Regolith Electrolysis Reactor Concepts for Oxygen and Metals Production on the Moon and Mars

    NASA Technical Reports Server (NTRS)

    Sibille, Laurent; Dominguez, Jesus A.

    2012-01-01

    The technology of direct electrolysis of molten lunar regolith to produce oxygen and molten metal alloys has progressed greatly in the last few years. The development of long-lasting inert anodes and cathode designs as well as techniques for the removal of molten products from the reactor has been demonstrated. The containment of chemically aggressive oxide and metal melts is very difficult at the operating temperatures ca. 1600 C. Containing the molten oxides in a regolith shell can solve this technical issue and can be achieved by designing a Joule-heated (sometimes called 'self-heating') reactor in which the electrolytic currents generate enough Joule heat to create a molten bath. Solutions obtained by multiphysics modeling allow the identification of the critical dimensions of concept reactors.

  19. Elliptical polarization of near-resonant linearly polarized probe light in optically pumped alkali metal vapor

    PubMed Central

    Li, Yingying; Wang, Zhiguo; Jin, Shilong; Yuan, Jie; Luo, Hui

    2017-01-01

    Optically pumped alkali metal atoms currently provide a sensitive solution for magnetic microscopic measurements. As the most practicable plan, Faraday rotation of linearly polarized light is extensively used in spin polarization measurements of alkali metal atoms. In some cases, near-resonant Faraday rotation is applied to improve the sensitivity. However, the near-resonant linearly polarized probe light is elliptically polarized after passing through optically pumped alkali metal vapor. The ellipticity of transmitted near-resonant probe light is numerically calculated and experimentally measured. In addition, we also analyze the negative impact of elliptical polarization on Faraday rotation measurements. From our theoretical estimate and experimental results, the elliptical polarization forms an inevitable error in spin polarization measurements. PMID:28216649

  20. Alkali-metal induced band structure deformation investigated by angle-resolved photoemission spectroscopy and first-principles calculations

    NASA Astrophysics Data System (ADS)

    Ito, S.; Feng, B.; Arita, M.; Someya, T.; Chen, W.-C.; Takayama, A.; Iimori, T.; Namatame, H.; Taniguchi, M.; Cheng, C.-M.; Tang, S.-J.; Komori, F.; Matsuda, I.

    2018-04-01

    Alkali-metal adsorption on the surface of materials is widely used for in situ surface electron doping, particularly for observing unoccupied band structures by angle-resolved photoemission spectroscopy (ARPES). However, the effects of alkali-metal atoms on the resulting band structures have yet to be fully investigated, owing to difficulties in both experiments and calculations. Here, we combine ARPES measurements on cesium-adsorbed ultrathin bismuth films with first-principles calculations of the electronic charge densities and demonstrate a simple method to evaluate alkali-metal induced band deformation. We reveal that deformation of bismuth surface bands is directly correlated with vertical charge-density profiles at each electronic state of bismuth. In contrast, a change in the quantized bulk bands is well described by a conventional rigid-band-shift picture. We discuss these two aspects of the band deformation holistically, considering spatial distributions of the electronic states and cesium-bismuth hybridization, and provide a prescription for applying alkali-metal adsorption to a wide range of materials.

  1. Applications of Laser-Induced Breakdown Spectroscopy (LIBS) in Molten Metal Processing

    NASA Astrophysics Data System (ADS)

    Hudson, Shaymus W.; Craparo, Joseph; De Saro, Robert; Apelian, Diran

    2017-10-01

    In order for metals to meet the demand for critical applications in the automotive, aerospace, and defense industries, tight control over the composition and cleanliness of the metal must be achieved. The use of laser-induced breakdown spectroscopy (LIBS) for applications in metal processing has generated significant interest for its ability to perform quick analyses in situ. The fundamentals of LIBS, current techniques for deployment on molten metal, demonstrated capabilities, and possible avenues for development are reviewed and discussed.

  2. Induction furnace testing of the durability of prototype crucibles in a molten metal environment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jablonski, Paul D.

    2005-09-01

    Engineered ceramic crucibles are commonly used to contain molten metal. Besides high temperature stability, other desired crucible characteristics include thermal shock resistance, minimal reaction with the molten metal and resistance to attack from the base metal oxide formed during melting. When used in an induction furnace, they can be employed as a “semi-permanent” crucible incorporating a dry ram backup and a ceramic cap. This report covers several 250-lb single melt crucible tests in an air melt induction furnace. These tests consisted of melting a charge of 17-4PH stainless steel, holding the charge molten for two hours before pouring off themore » heat and then subsequently sectioning the crucible to review the extent of erosion, penetration and other physical characteristics. Selected temperature readings were made throughout each melt. Chemistry samples were also taken from each heat periodically throughout the hold. The manganese level was observed to affect the rate of chromium loss in a non-linear fashion.« less

  3. First-principles study on interlayer state in alkali and alkaline earth metal atoms intercalated bilayer graphene

    NASA Astrophysics Data System (ADS)

    Kaneko, Tomoaki; Saito, Riichiro

    2017-11-01

    Energetics and electronic structures of alkali metal (Li, Na, K, Rb, and Cs) and alkaline earth metal (Be, Mg, Ca, Sr, and Ba) atoms intercalated bilayer graphene are systematically investigated using first-principles calculations based on density functional theory. Formation of alkali and alkaline earth metal atoms intercalated bilayer graphene is exothermic except for Be and Mg. The interlayer state between two graphene layers is occupied for K, Rb, Cs, Ca, Sr, and Ba. We find that the energetic position of the interlayer states between bilayer graphene monotonically shifts downward with increasing of interlayer distance. The interlayer distances of more than 4.5 Å and 4.0 Å, respectively, are necessary for the occupation of the interlayer state in bilayer graphene for alkali and alkaline earth metal atoms, which is almost independent of the intercalant metal species. We discuss the relevance to occurrence of superconductivity for the metal intercalated bilayer graphene in terms of the occupation of the interlayer state and the phonon frequency of metal ions.

  4. Alkali metal intercalated fullerene-like MS(2) (M = W, Mo) nanoparticles and their properties.

    PubMed

    Zak, Alla; Feldman, Yishay; Lyakhovitskaya, Vera; Leitus, Gregory; Popovitz-Biro, Ronit; Wachtel, Ellen; Cohen, Hagai; Reich, Shimon; Tenne, Reshef

    2002-05-01

    Layered metal disulfides-MS(2) (M = Mo, W) in the form of fullerene-like nanoparticles and in the form of platelets (crystallites of the 2H polytype) have been intercalated by exposure to alkali metal (potassium and sodium) vapor using a two-zone transport method. The composition of the intercalated systems was established using X-ray energy dispersive spectrometer and X-ray photoelectron spectroscopy (XPS). The alkali metal concentration in the host lattice was found to depend on the kind of sample and the experimental conditions. Furthermore, an inhomogeneity of the intercalated samples was observed. The product consisted of both nonintercalated and intercalated phases. X-ray diffraction analysis and transmission electron microscopy of the samples, which were not exposed to the ambient atmosphere, showed that they suffered little change in their lattice parameters. On the other hand, after exposure to ambient atmosphere, substantial increase in the interplanar spacing (3-5 A) was observed for the intercalated phases. Insertion of one to two water molecules per intercalated metal atom was suggested as a possible explanation for this large expansion along the c-axis. Deintercalation of the hydrated alkali atoms and restacking of the MS(2) layers was observed in all the samples after prolonged exposure to the atmosphere. Electric field induced deintercalation of the alkali metal atoms from the host lattice was also observed by means of the XPS technique. Magnetic moment measurements for all the samples indicate a diamagnetic to paramagnetic transition after intercalation. Measurements of the transport properties reveal a semiconductor to metal transition for the heavily K intercalated 2H-MoS(2). Other samples show several orders of magnitude decrease in resistivity and two- to five-fold decrease in activation energies upon intercalation. These modifications are believed to occur via charge transfer from the alkali metal to the conduction band of the host lattice

  5. Chemical interactions and thermodynamic studies in aluminum alloy/molten salt systems

    NASA Astrophysics Data System (ADS)

    Narayanan, Ramesh

    The recycling of aluminum and aluminum alloys such as Used Beverage Container (UBC) is done under a cover of molten salt flux based on (NaCl-KCl+fluorides). The reactions of aluminum alloys with molten salt fluxes have been investigated. Thermodynamic calculations are performed in the alloy/salt flux systems which allow quantitative predictions of the equilibrium compositions. There is preferential reaction of Mg in Al-Mg alloy with molten salt fluxes, especially those containing fluorides like NaF. An exchange reaction between Al-Mg alloy and molten salt flux has been demonstrated. Mg from the Al-Mg alloy transfers into the salt flux while Na from the salt flux transfers into the metal. Thermodynamic calculations indicated that the amount of Na in metal increases as the Mg content in alloy and/or NaF content in the reacting flux increases. This is an important point because small amounts of Na have a detrimental effect on the mechanical properties of the Al-Mg alloy. The reactions of Al alloys with molten salt fluxes result in the formation of bluish purple colored "streamers". It was established that the streamer is liquid alkali metal (Na and K in the case of NaCl-KCl-NaF systems) dissipating into the melt. The melts in which such streamers were observed are identified. The metal losses occurring due to reactions have been quantified, both by thermodynamic calculations and experimentally. A computer program has been developed to calculate ternary phase diagrams in molten salt systems from the constituting binary phase diagrams, based on a regular solution model. The extent of deviation of the binary systems from regular solution has been quantified. The systems investigated in which good agreement was found between the calculated and experimental phase diagrams included NaF-KF-LiF, NaCl-NaF-NaI and KNOsb3-TINOsb3-LiNOsb3. Furthermore, an insight has been provided on the interrelationship between the regular solution parameters and the topology of the phase

  6. Molten salt oxidation of organic hazardous waste with high salt content.

    PubMed

    Lin, Chengqian; Chi, Yong; Jin, Yuqi; Jiang, Xuguang; Buekens, Alfons; Zhang, Qi; Chen, Jian

    2018-02-01

    Organic hazardous waste often contains some salt, owing to the widespread use of alkali salts during industrial manufacturing processes. These salts cause complications during the treatment of this type of waste. Molten salt oxidation is a flameless, robust thermal process, with inherent capability of destroying the organic constituents of wastes, while retaining the inorganic ingredients in the molten salt. In the present study, molten salt oxidation is employed for treating a typical organic hazardous waste with a high content of alkali salts. The hazardous waste derives from the production of thiotriazinone. Molten salt oxidation experiments have been conducted using a lab-scale molten salt oxidation reactor, and the emissions of CO, NO, SO 2 , HCl and dioxins are studied. Impacts are investigated from the composition of the molten salts, the types of feeding tube, the temperature of molten carbonates and the air factor. Results show that the waste can be oxidised effectively in a molten salt bath. Temperature of molten carbonates plays the most important role. With the temperature rising from 600 °C to 750 °C, the oxidation efficiency increases from 91.1% to 98.3%. Compared with the temperature, air factor has but a minor effect, as well as the composition of the molten salts and the type of feeding tube. The molten carbonates retain chlorine with an efficiency higher than 99.9% and the emissions of dioxins are below 8 pg TEQ g -1 sample. The present study shows that molten salt oxidation is a promising alternative for the disposal of organic hazardous wastes containing a high salt content.

  7. Ion conducting fluoropolymer carbonates for alkali metal ion batteries

    DOEpatents

    DeSimone, Joseph M.; Pandya, Ashish; Wong, Dominica; Balsara, Nitash P.; Thelen, Jacob; Devaux, Didier

    2017-09-05

    Liquid or solid electrolyte compositions are described that comprise a homogeneous solvent system and an alkali metal salt dissolved in said solvent system. The solvent system may comprise a fluoropolymer, having one or two terminal carbonate groups covalently coupled thereto. Batteries containing such electrolyte compositions are also described.

  8. Aqueous alkali metal hydroxide insoluble cellulose ether membrane

    NASA Technical Reports Server (NTRS)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1969-01-01

    A membrane that is insoluble in an aqueous alkali metal hydroxide medium is described. The membrane is a resin which is a water-soluble C2-C4 hydroxyalkyl cellulose ether polymer and an insolubilizing agent for controlled water sorption, a dialytic and electrodialytic membrane. It is particularly useful as a separator between electrodes or plates in an alkaline storage battery.

  9. Evidence for alkali metal formation at a cathode interface of organic electroluminescent devices by thermal decomposition of alkali metal carboxylates during their vapor deposition

    NASA Astrophysics Data System (ADS)

    Ganzorig, Chimed; Fujihira, Masamichi

    2004-11-01

    This study examines the possibility of thermal decomposition of Na salts of acetate, benzoate, and fluoride during vacuum vapor deposition using a quartz crystal microbalance to measure negative frequency shift (Δf) caused by increasing mass deposited from the same amount of source materials. Cs acetate is also examined. We compare the negative frequency shift-source current (Δf -I) curves of the Na salts with those of organic materials such as tris(8-hydroxyquinoline)aluminum and N ,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine. CH3COONa and C6H5COONa exhibit much lower Δf than the organic materials. CH3COOCs gives much larger Δf than CH3COONa due to the higher atomic weight of Cs. These exhibit clear evidence for alkali metal formation by thermal decomposition during vapor deposition of alkali metal carboxylates.

  10. Thermodynamics of Liquid Alkali Metals and Their Binary Alloys

    NASA Astrophysics Data System (ADS)

    Thakor, P. B.; Patel, Minal H.; Gajjar, P. N.; Jani, A. R.

    2009-07-01

    The theoretical investigation of thermodynamic properties like internal energy, entropy, Helmholtz free energy, heat of mixing (ΔE) and entropy of mixing (ΔS) of liquid alkali metals and their binary alloys are reported in the present paper. The effect of concentration on the thermodynamic properties of Ac1Bc2 alloy of the alkali-alkali elements is investigated and reported for the first time using our well established local pseudopotential. To investigate influence of exchange and correlation effects, we have used five different local field correction functions viz; Hartree(H), Taylor(T), Ichimaru and Utsumi(IU), Farid et al. (F) and Sarkar et al. (S). The increase of concentration C2, increases the internal energy and Helmholtz free energy of liquid alloy Ac1Bc2. The behavior of present computation is not showing any abnormality in the outcome and hence confirms the applicability of our model potential in explaining the thermodynamics of liquid binary alloys.

  11. High capacity nickel battery material doped with alkali metal cations

    DOEpatents

    Jackovitz, John F.; Pantier, Earl A.

    1982-05-18

    A high capacity battery material is made, consisting essentially of hydrated Ni(II) hydroxide, and about 5 wt. % to about 40 wt. % of Ni(IV) hydrated oxide interlayer doped with alkali metal cations selected from potassium, sodium and lithium cations.

  12. Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se2 solar cells on glass substrate

    NASA Astrophysics Data System (ADS)

    Kamikawa, Yukiko; Nishinaga, Jiro; Ishizuka, Shogo; Tayagaki, Takeshi; Guthrey, Harvey; Shibata, Hajime; Matsubara, Koji; Niki, Shigeru

    2018-03-01

    The precise control of alkali-metal concentrations in Cu(In,Ga)Se2 (CIGS) solar cells via post deposition treatment (PDT) has recently attracted attention. When PDT is performed at an elevated temperature, an accompanying annealing effect is expected. Here, we investigate how thermal annealing affects the redistribution of alkali metals in CIGS solar cells on glass substrates and the properties of the solar cells. In addition, we investigate the origin of non-homogeneous alkali-metal depth profiles that are typical of CIGS grown using a three-stage process. In particular, we use secondary-ion mass spectrometry measurements of the ion concentration as a function of distance from the CIGS surface to investigate the impact of thermal annealing on the distribution of alkali metals (Na, Ka, and Rb) and constituent elements (Ga and In) in the CIGS absorbers. We find that the depth profiles of the alkali metals strongly reflect the density of sites that tend to accommodate alkali metals, i.e., vacancies. Annealing at elevated temperature caused a redistribution of the alkali metals. The thermal-diffusion kinetics of alkali metals depends strongly on the species involved. We introduced low flux potassium fluoride (KF) to study a side effect of KF-PDT, i.e., Na removal from CIGS, separately from its predominant effects such as surface modification. When sufficient amounts of Na are supplied from the soda lime glass via annealing at an elevated temperature, the negative effect was not apparent. Conversely, when the Na supply was not sufficient, it caused a deterioration of the photovoltaic properties.

  13. Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se 2 solar cells on glass substrate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kamikawa, Yukiko; Nishinaga, Jiro; Ishizuka, Shogo

    The precise control of alkali-metal concentrations in Cu(In,Ga)Se 2 (CIGS) solar cells via post deposition treatment (PDT) has recently attracted attention. When PDT is performed at an elevated temperature, an accompanying annealing effect is expected. Here, we investigate how thermal annealing affects the redistribution of alkali metals in CIGS solar cells on glass substrates and the properties of the solar cells. In addition, we investigate the origin of non-homogeneous alkali-metal depth profiles that are typical of CIGS grown using a three-stage process. In particular, we use secondary-ion mass spectrometry measurements of the ion concentration as a function of distance frommore » the CIGS surface to investigate the impact of thermal annealing on the distribution of alkali metals (Na, Ka, and Rb) and constituent elements (Ga and In) in the CIGS absorbers. We find that the depth profiles of the alkali metals strongly reflect the density of sites that tend to accommodate alkali metals, i.e., vacancies. Annealing at elevated temperature caused a redistribution of the alkali metals. The thermal-diffusion kinetics of alkali metals depends strongly on the species involved. We introduced low flux potassium fluoride (KF) to study a side effect of KF-PDT, i.e., Na removal from CIGS, separately from its predominant effects such as surface modification. When sufficient amounts of Na are supplied from the soda lime glass via annealing at an elevated temperature, the negative effect was not apparent. Conversely, when the Na supply was not sufficient, it caused a deterioration of the photovoltaic properties.« less

  14. Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se 2 solar cells on glass substrate

    DOE PAGES

    Kamikawa, Yukiko; Nishinaga, Jiro; Ishizuka, Shogo; ...

    2018-03-07

    The precise control of alkali-metal concentrations in Cu(In,Ga)Se 2 (CIGS) solar cells via post deposition treatment (PDT) has recently attracted attention. When PDT is performed at an elevated temperature, an accompanying annealing effect is expected. Here, we investigate how thermal annealing affects the redistribution of alkali metals in CIGS solar cells on glass substrates and the properties of the solar cells. In addition, we investigate the origin of non-homogeneous alkali-metal depth profiles that are typical of CIGS grown using a three-stage process. In particular, we use secondary-ion mass spectrometry measurements of the ion concentration as a function of distance frommore » the CIGS surface to investigate the impact of thermal annealing on the distribution of alkali metals (Na, Ka, and Rb) and constituent elements (Ga and In) in the CIGS absorbers. We find that the depth profiles of the alkali metals strongly reflect the density of sites that tend to accommodate alkali metals, i.e., vacancies. Annealing at elevated temperature caused a redistribution of the alkali metals. The thermal-diffusion kinetics of alkali metals depends strongly on the species involved. We introduced low flux potassium fluoride (KF) to study a side effect of KF-PDT, i.e., Na removal from CIGS, separately from its predominant effects such as surface modification. When sufficient amounts of Na are supplied from the soda lime glass via annealing at an elevated temperature, the negative effect was not apparent. Conversely, when the Na supply was not sufficient, it caused a deterioration of the photovoltaic properties.« less

  15. Transversely diode-pumped alkali metal vapour laser

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Parkhomenko, A I; Shalagin, A M

    2015-09-30

    We have studied theoretically the operation of a transversely diode-pumped alkali metal vapour laser. For the case of high-intensity laser radiation, we have obtained an analytical solution to a complex system of differential equations describing the laser. This solution allows one to exhaustively determine all the energy characteristics of the laser and to find optimal parameters of the working medium and pump radiation (temperature, buffer gas pressure, and intensity and width of the pump spectrum). (lasers)

  16. The structure of liquid alkali nitrates and nitrites

    DOE PAGES

    Wilding, Martin C.; Wilson, Mark; Ribeiro, Mauro C. C.; ...

    2017-07-26

    State of the art high energy X-ray diffraction experiments and simulation models (employing a description of charge transfer) are applied to pure molten alkali nitrates and nitrites and uncover significant emerging structure.

  17. A Molten Salt Lithium-Oxygen Battery.

    PubMed

    Giordani, Vincent; Tozier, Dylan; Tan, Hongjin; Burke, Colin M; Gallant, Betar M; Uddin, Jasim; Greer, Julia R; McCloskey, Bryan D; Chase, Gregory V; Addison, Dan

    2016-03-02

    Despite the promise of extremely high theoretical capacity (2Li + O2 ↔ Li2O2, 1675 mAh per gram of oxygen), many challenges currently impede development of Li/O2 battery technology. Finding suitable electrode and electrolyte materials remains the most elusive challenge to date. A radical new approach is to replace volatile, unstable and air-intolerant organic electrolytes common to prior research in the field with alkali metal nitrate molten salt electrolytes and operate the battery above the liquidus temperature (>80 °C). Here we demonstrate an intermediate temperature Li/O2 battery using a lithium anode, a molten nitrate-based electrolyte (e.g., LiNO3-KNO3 eutectic) and a porous carbon O2 cathode with high energy efficiency (∼95%) and improved rate capability because the discharge product, lithium peroxide, is stable and moderately soluble in the molten salt electrolyte. The results, supported by essential state-of-the-art electrochemical and analytical techniques such as in situ pressure and gas analyses, scanning electron microscopy, rotating disk electrode voltammetry, demonstrate that Li2O2 electrochemically forms and decomposes upon cycling with discharge/charge overpotentials as low as 50 mV. We show that the cycle life of such batteries is limited only by carbon reactivity and by the uncontrolled precipitation of Li2O2, which eventually becomes electrically disconnected from the O2 electrode.

  18. Theory of metal atom-water interactions and alkali halide dimers

    NASA Technical Reports Server (NTRS)

    Jordan, K. D.; Kurtz, H. A.

    1982-01-01

    Theoretical studies of the interactions of metal atoms with water and some of its isoelectronic analogs, and of the properties of alkali halides and their aggregates are discussed. Results are presented of ab initio calculations of the heats of reaction of the metal-water adducts and hydroxyhydrides of Li, Be, B, Na, Mg, and Al, and of the bond lengths and angles an; the heats of reaction for the insertion of Al into HF, H2O, NH3, H2S and CH3OH, and Be and Mg into H2O. Calculations of the electron affinities and dipole moments and polarizabilities of selected gas phase alkali halide monomers and dimers are discussed, with particular attention given to results of calculations of the polarizability of LiF taking into account electron correlation effects, and the polarizability of the dimer (LiF)2.

  19. Two techniques enable sampling of filtered and unfiltered molten metals

    NASA Technical Reports Server (NTRS)

    Burris, L., Jr.; Pierce, R. D.; Tobias, K. R.; Winsch, I. O.

    1967-01-01

    Filtered samples of molten metals are obtained by filtering through a plug of porous material fitted in the end of a sample tube, and unfiltered samples are obtained by using a capillary-tube extension rod with a perforated bucket. With these methods there are no sampling errors or loss of liquid.

  20. Low-Temperature Synthesis of New Ternary Chalcogenide Compounds of Copper, Gold, and Mercury Using Alkali Metal Polychalcogenide Fluxes

    NASA Astrophysics Data System (ADS)

    Park, Younbong

    In last two decades great efforts have been exerted to find new materials with interesting optical, electrical, and catalytic properties. Metal chalcogenides have been studied extensively because of their interesting physical properties and rich structural chemistry, among the potential materials. Prior to this work, most known metal chalcogenides had been synthesized at high temperature (T > 500^circC). Intermediate temperature synthesis in solid state chemistry was seldom pursued because of the extremely slow diffusion rates between reactants. This intermediate temperature regime could be a new synthesis condition if one looks for new materials with unusual structural features and properties. Metastable or kinetically stable compounds can be stabilized in this intermediate temperature regime, in contrast to the thermodynamically stable high temperature compounds. Molten salts, especially alkali metal polychalcogenide fluxes, can provide a route for exploring new chalcogenide materials at intermediate temperatures. These fluxes are very reactive and melt as low as 145^circC (mp of K_2S_4). Using these fluxes as reaction media, we have encountered many novel chalcogenide compounds with unusual structures and interesting electrical properties (semiconductors to metallic conductors). Low-dimensional polychalcogenide compounds of alpha-ACuQ_4 (A = K, Cs; Q = S, Se), beta -KCuS_4, KAuQ_5 (Q = S, Se), K_3AuSe_ {13}, Na_3AuSe _8, and CsAuSe_3 exhibit the beautiful structural diversity and bonding flexibility of the polychalcogenide ligands. In addition, many novel chalcogenide compounds of Cu, Hg, and Au with low-dimensional structures. The preparation of novel mixed -valence Cu compounds, K_2Cu _5Te_5, Cs _3Cu_8Te_ {10}, Na_3Cu _4Se_4, K _3Cu_8S_4 Te_2, and KCu_4 S_2Te, which show interesting metallic properties, especially underscores the enormous potential of the molten salt method for the synthesis of new chalcogenide materials with interesting physical properties

  1. Performance Testing of Molten Regolith Electrolysis with Transfer of Molten Material for the Production of Oxygen and Metals on the Moon

    NASA Technical Reports Server (NTRS)

    Sibille, Laurent; Sadoway, Donald; Tripathy, Prabhat; Standish, Evan; Sirk, Aislinn; Melendez, Orlando; Stefanescu, Doru

    2010-01-01

    Previously, we have demonstrated the production of oxygen by electrolysis of molten regolith simulants at temperatures near 1600 C. Using an inert anode and suitable cathode, direct electrolysis (no supporting electrolyte) of the molten silicate is carried out, resulting in the production of molten metallic products at the cathode and oxygen gas at the anode. Initial direct measurements of current efficiency have confirmed that the process offer potential advantages of high oxygen production rates in a smaller footprint facility landed on the moon, with a minimum of consumables brought from Earth. We now report the results of a scale-up effort toward the goal of achieving production rates equivalent to 1 metric ton O2/year, a benchmark established for the support of a lunar base. We previously reported on the electrochemical behavior of the molten electrolyte as dependent on anode material, sweep rate and electrolyte composition in batches of 20-200g and at currents of less than 0.5 A. In this paper, we present the results of experiments performed at currents up to 10 Amperes) and in larger volumes of regolith simulant (500 g - 1 kg) for longer durations of electrolysis. The technical development of critical design components is described, including: inert anodes capable of passing continuous currents of several Amperes, container materials selection, direct gas analysis capability to determine the gas components co-evolving with oxygen. To allow a continuous process, a system has been designed and tested to enable the withdrawal of cathodically-reduced molten metals and spent molten oxide electrolyte. The performance of the withdrawal system is presented and critiqued. The design of the electrolytic cell and the configuration of the furnace were supported by modeling the thermal environment of the system in an effort to realize a balance between external heating and internal joule heating. We will discuss the impact these simulations and experimental findings have

  2. Thermal Coefficient of Redox Potential of Alkali Metals

    NASA Astrophysics Data System (ADS)

    Fukuzumi, Yuya; Hinuma, Yoyo; Moritomo, Yutaka

    2018-05-01

    The thermal coefficient (α) of redox potential (V) is a significant physical quantity that converts the thermal energy into electric energy. In this short note, we carefully determined α of alkali metals (A = Li and Na) against electrolyte solution. The obtained α is much larger than that expected from the specific heat (CpA) of solid A and depends on electrolyte solution. These observations indicate that the solvent has significant effect on α.

  3. Alkali metal carbon dioxide electrochemical system for energy storage and/or conversion of carbon dioxide to oxygen

    NASA Technical Reports Server (NTRS)

    Hagedorn, Norman H. (Inventor)

    1993-01-01

    An alkali metal, such as lithium, is the anodic reactant; carbon dioxide or a mixture of carbon dioxide and carbon monoxide is the cathodic reactant; and carbonate of the alkali metal is the electrolyte in an electrochemical cell for the storage and delivery of electrical energy. Additionally, alkali metal-carbon dioxide battery systems include a plurality of such electrochemical cells. Gold is a preferred catalyst for reducing the carbon dioxide at the cathode. The fuel cell of the invention produces electrochemical energy through the use of an anodic reactant which is extremely energetic and light, and a cathodic reactant which can be extracted from its environment and therefore exacts no transportation penalty. The invention is, therefore, especially useful in extraterrestrial environments.

  4. Coordination effect-regulated CO2 capture with an alkali metal onium salts/crown ether system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yang, Zhen-Zhen; Jiang, Deen; Zhu, Xiang

    2014-01-01

    A coordination effect was employed to realize equimolar CO2 absorption, adopting easily synthesized amino group containing absorbents (alkali metal onium salts). The essence of our strategy was to increase the steric hindrance of cations so as to enhance a carbamic acid pathway for CO2 capture. Our easily synthesized alkali metal amino acid salts or phenolates were coordinated with crown ethers, in which highly sterically hindered cations were obtained through a strong coordination effect of crown ethers with alkali metal cations. For example, a CO2 capacity of 0.99 was attained by potassium prolinate/18-crown-6, being characterized by NMR, FT-IR, and quantum chemistrymore » calculations to go through a carbamic acid formation pathway. The captured CO2 can be stripped under very mild conditions (50 degrees C, N-2). Thus, this protocol offers an alternative for the development of technological innovation towards efficient and low energy processes for carbon capture and sequestration.« less

  5. Chemical Reduction of SIM MOX in Molten Lithium Chloride Using Lithium Metal Reductant

    NASA Astrophysics Data System (ADS)

    Kato, Tetsuya; Usami, Tsuyoshi; Kurata, Masaki; Inoue, Tadashi; Sims, Howard E.; Jenkins, Jan A.

    2007-09-01

    A simulated spent oxide fuel in a sintered pellet form, which contained the twelve elements U, Pu, Am, Np, Cm, Ce, Nd, Sm, Ba, Zr,Mo, and Pd, was reduced with Li metal in a molten LiCl bath at 923 K. More than 90% of U and Pu were reduced to metal to form a porous alloy without significant change in the Pu/U ratio. Small fractions of Pu were also combined with Pd to form stable alloys. In the gap of the porous U-Pu alloy, the aggregation of the rare-earth (RE) oxide was observed. Some amount of the RE elements and the actinoides leached from the pellet. The leaching ratio of Am to the initially loaded amount was only several percent, which was far from about 80% obtained in the previous ones on simple MOX including U, Pu, and Am. The difference suggests that a large part of Am existed in the RE oxide rather than in the U-Pu alloy. The detection of the RE elements and actinoides in the molten LiCl bath seemed to indicate that they dissolved into the molten LiCl bath containing the oxide ion, which is the by-product of the reduction, as solubility of RE elements was measured in the molten LiCl-Li2O previously.

  6. Thermal Stress and Heat Transfer Coefficient for Ceramics Stalk Having Protuberance Dipping into Molten Metal

    NASA Astrophysics Data System (ADS)

    Noda, Nao-Aki; Hendra; Li, Wenbin; Takase, Yasushi; Ogura, Hiroki; Higashi, Yusuke

    Low pressure die casting is defined as a net shape casting technology in which the molten metal is injected at high speeds and pressure into a metallic die. The low pressure die casting process plays an increasingly important role in the foundry industry as a low-cost and high-efficiency precision forming technique. In the low pressure die casting process is that the permanent die and filling systems are placed over the furnace containing the molten alloy. The filling of the cavity is obtained by forcing the molten metal, by means of a pressurized gas, to rise into a ceramic tube having protuberance, which connects the die to the furnace. The ceramics tube, called stalk, has high temperature resistance and high corrosion resistance. However, attention should be paid to the thermal stress when the stalk having protuberance is dipped into the molten aluminum. It is important to reduce the risk of fracture that may happen due to the thermal stresses. In this paper, thermo-fluid analysis is performed to calculate surface heat transfer coefficient. The finite element method is applied to calculate the thermal stresses when the stalk having protuberance is dipped into the crucible with varying dipping speeds. It is found that the stalk with or without protuberance should be dipped into the crucible slowly to reduce the thermal stress.

  7. 40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fluorinated carboxylic acid alkali metal salts. 721.4663 Section 721.4663 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4663...

  8. Ultrafast selective transport of alkali metal ions in metal organic frameworks with subnanometer pores

    PubMed Central

    Zhang, Huacheng; Hou, Jue; Hu, Yaoxin; Wang, Peiyao; Ou, Ranwen; Jiang, Lei; Liu, Jefferson Zhe; Freeman, Benny D.; Hill, Anita J.; Wang, Huanting

    2018-01-01

    Porous membranes with ultrafast ion permeation and high ion selectivity are highly desirable for efficient mineral separation, water purification, and energy conversion, but it is still a huge challenge to efficiently separate monatomic ions of the same valence and similar sizes using synthetic membranes. We report metal organic framework (MOF) membranes, including ZIF-8 and UiO-66 membranes with uniform subnanometer pores consisting of angstrom-sized windows and nanometer-sized cavities for ultrafast selective transport of alkali metal ions. The angstrom-sized windows acted as ion selectivity filters for selection of alkali metal ions, whereas the nanometer-sized cavities functioned as ion conductive pores for ultrafast ion transport. The ZIF-8 and UiO-66 membranes showed a LiCl/RbCl selectivity of ~4.6 and ~1.8, respectively, which are much greater than the LiCl/RbCl selectivity of 0.6 to 0.8 measured in traditional porous membranes. Molecular dynamics simulations suggested that ultrafast and selective ion transport in ZIF-8 was associated with partial dehydration effects. This study reveals ultrafast and selective transport of monovalent ions in subnanometer MOF pores and opens up a new avenue to develop unique MOF platforms for efficient ion separations in the future. PMID:29487910

  9. Ultrafast selective transport of alkali metal ions in metal organic frameworks with subnanometer pores.

    PubMed

    Zhang, Huacheng; Hou, Jue; Hu, Yaoxin; Wang, Peiyao; Ou, Ranwen; Jiang, Lei; Liu, Jefferson Zhe; Freeman, Benny D; Hill, Anita J; Wang, Huanting

    2018-02-01

    Porous membranes with ultrafast ion permeation and high ion selectivity are highly desirable for efficient mineral separation, water purification, and energy conversion, but it is still a huge challenge to efficiently separate monatomic ions of the same valence and similar sizes using synthetic membranes. We report metal organic framework (MOF) membranes, including ZIF-8 and UiO-66 membranes with uniform subnanometer pores consisting of angstrom-sized windows and nanometer-sized cavities for ultrafast selective transport of alkali metal ions. The angstrom-sized windows acted as ion selectivity filters for selection of alkali metal ions, whereas the nanometer-sized cavities functioned as ion conductive pores for ultrafast ion transport. The ZIF-8 and UiO-66 membranes showed a LiCl/RbCl selectivity of ~4.6 and ~1.8, respectively, which are much greater than the LiCl/RbCl selectivity of 0.6 to 0.8 measured in traditional porous membranes. Molecular dynamics simulations suggested that ultrafast and selective ion transport in ZIF-8 was associated with partial dehydration effects. This study reveals ultrafast and selective transport of monovalent ions in subnanometer MOF pores and opens up a new avenue to develop unique MOF platforms for efficient ion separations in the future.

  10. [On-line analysis and mass concentration characters of the alkali metal ions of PM10 in Beijing].

    PubMed

    Zhang, Kai; Wang, Yue-Si; Wen, Tian-Xue; Liu, Guang-Ren; Hu, Bo; Zhao, Ya-Nan

    2008-01-01

    The mass concentration characters and the sources of water-soluble alkali metal ions in PM10 in 2004 and 2005 in Beijing were analyzed by using the system of rapid collection of particles. The result showed that the average concentration of Na+, K+, Mg2+ and Ca2+ was 0.5-1.4, 0.5-2.5, 0.1-0.5 and 0.6-5.8 microg/m3, respectively. The highest and lowest concentration appeared in different seasons for the alkali metal ions, which was related to the quality and source. The concentration of alkali metal ions was no difference between the heating period and no heating period, which meant the heating was not the main source. Sea salt and soil were the important sources of Na+. The source of K+ came from biomass burning and vegetation. Soil was the large source of Mg2+ and Ca2+. The alkali metal ions appeared different daily variation in different seasons. Precipitation could decrease the concentration of Na+, K+, Mg2+ and Ca2+, which was 10%-70%, 20%-80%, 10%-77%, 5%-80% respectively.

  11. Fluorescent probes and bioimaging: alkali metals, alkaline earth metals and pH.

    PubMed

    Yin, Jun; Hu, Ying; Yoon, Juyoung

    2015-07-21

    All living species and life forms have an absolute requirement for bio-functional metals and acid-base equilibrium chemistry owing to the critical roles they play in biological processes. Hence, a great need exists for efficient methods to detect and monitor biometals and acids. In the last few years, great attention has been paid to the development of organic molecule based fluorescent chemosensors. The availability of new synthetic fluorescent probes has made fluorescence microscopy an indispensable tool for tracing biologically important molecules and in the area of clinical diagnostics. This review highlights the recent advances that have been made in the design and bioimaging applications of fluorescent probes for alkali metals and alkaline earth metal cations, including lithium, sodium and potassium, magnesium and calcium, and for pH determination within biological systems.

  12. Designable ultra-smooth ultra-thin solid-electrolyte interphases of three alkali metal anodes.

    PubMed

    Gu, Yu; Wang, Wei-Wei; Li, Yi-Juan; Wu, Qi-Hui; Tang, Shuai; Yan, Jia-Wei; Zheng, Ming-Sen; Wu, De-Yin; Fan, Chun-Hai; Hu, Wei-Qiang; Chen, Zhao-Bin; Fang, Yuan; Zhang, Qing-Hong; Dong, Quan-Feng; Mao, Bing-Wei

    2018-04-09

    Dendrite growth of alkali metal anodes limited their lifetime for charge/discharge cycling. Here, we report near-perfect anodes of lithium, sodium, and potassium metals achieved by electrochemical polishing, which removes microscopic defects and creates ultra-smooth ultra-thin solid-electrolyte interphase layers at metal surfaces for providing a homogeneous environment. Precise characterizations by AFM force probing with corroborative in-depth XPS profile analysis reveal that the ultra-smooth ultra-thin solid-electrolyte interphase can be designed to have alternating inorganic-rich and organic-rich/mixed multi-layered structure, which offers mechanical property of coupled rigidity and elasticity. The polished metal anodes exhibit significantly enhanced cycling stability, specifically the lithium anodes can cycle for over 200 times at a real current density of 2 mA cm -2 with 100% depth of discharge. Our work illustrates that an ultra-smooth ultra-thin solid-electrolyte interphase may be robust enough to suppress dendrite growth and thus serve as an initial layer for further improved protection of alkali metal anodes.

  13. Theoretical evaluation on selective adsorption characteristics of alkali metal-based sorbents for gaseous oxidized mercury.

    PubMed

    Tang, Hongjian; Duan, Yufeng; Zhu, Chun; Cai, Tianyi; Li, Chunfeng; Cai, Liang

    2017-10-01

    Alkali metal-based sorbents are potential for oxidized mercury (Hg 2+ ) selective adsorption but show hardly effect to elemental mercury (Hg 0 ) in flue gas. Density functional theory (DFT) was employed to investigate the Hg 0 and HgCl 2 adsorption mechanism over alkali metal-based sorbents, including calcium oxide (CaO), magnesium oxide (MgO), potassium chloride (KCl) and sodium chloride (NaCl). Hg 0 was found to weakly interact with CaO (001), MgO (001), KCl (001) and NaCl (001) surfaces while HgCl 2 was effectively adsorbed on top-O and top-Cl sites. Charge transfer and bond population were calculated to discuss the covalency and ionicity of HgCl 2 bonding with the adsorption sites. The partial density of states (PDOS) analysis manifests that HgCl 2 strongly interacts with surface sites through the orbital hybridizations between Hg and top O or Cl. Frontier molecular orbital (FMO) energy and Mulliken electronegativity are introduced as the quantitative criteria to evaluate the reactivity of mercury species and alkali metal-based sorbents. HgCl 2 is identified as a Lewis acid and more reactive than Hg 0 . The Lewis basicity of the four alkali metal-based sorbents is predicted as the increasing order: NaCl < MgO < KCl < CaO, in consistence with the trend of HgCl 2 adsorption energies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Electrolytic method to make alkali alcoholates using ion conducting alkali electrolyte/separator

    DOEpatents

    Joshi, Ashok V [Salt Lake City, UT; Balagopal, Shekar [Sandy, UT; Pendelton, Justin [Salt Lake City, UT

    2011-12-13

    Alkali alcoholates, also called alkali alkoxides, are produced from alkali metal salt solutions and alcohol using a three-compartment electrolytic cell. The electrolytic cell includes an anolyte compartment configured with an anode, a buffer compartment, and a catholyte compartment configured with a cathode. An alkali ion conducting solid electrolyte configured to selectively transport alkali ions is positioned between the anolyte compartment and the buffer compartment. An alkali ion permeable separator is positioned between the buffer compartment and the catholyte compartment. The catholyte solution may include an alkali alcoholate and alcohol. The anolyte solution may include at least one alkali salt. The buffer compartment solution may include a soluble alkali salt and an alkali alcoholate in alcohol.

  15. Enhancing Skin Permeation of Biphenylacetic Acid (BPA) Using Salt Formation with Organic and Alkali Metal Bases

    PubMed Central

    Pawar, Vijay; Naik, Prashant; Giridhar, Rajani; Yadav, Mange Ram

    2015-01-01

    In the present study, a series of organic and alkali metal salts of biphenylacetic acid (BPA) have been prepared and evaluated in vitro for percutaneous drug delivery. The physicochemical properties of BPA salts were determined using solubility measurements, DSC, and IR. The DSC thermogram and FTIR spectra confirmed the salt formation with organic and alkali metal bases. Among the series, salts with organic amines (ethanolamine, diethanolamine, triethanolamine, and diethylamine) had lowered melting points while the alkali metal salt (sodium) had a higher melting point than BPA. The in vitro study showed that salt formation improves the physicochemical properties of BPA, leading to improved permeability through the skin. Amongst all the prepared salts, ethanolamine salt (1b) showed 7.2- and 5.4-fold higher skin permeation than the parent drug at pH 7.4 and 5.0, respectively, using rat skin. PMID:26839810

  16. Adsorption of alkali and alkaline earth metal atoms and dimers on monolayer germanium carbide

    NASA Astrophysics Data System (ADS)

    Gökçe, Aytaç Gürhan; Ersan, Fatih

    2017-01-01

    First-principles plane wave calculations have been performed to study the adsorption of alkali and alkaline earth metals on monolayer germanium carbide (GeC). We found that the favourable adsorption sites on GeC sheet for single alkali and alkaline earth adatoms are generally different from graphene or germanene. Among them, Mg, Na and their dimers have weakly bounded to GeC due to their closed valence electron shells, so they may have high mobility on GeC. Two different levels of adatom coverage (? and ?) have been investigated and we concluded that different electronic structures and magnetic moments for both coverages owing to alkali and alkaline earth atoms have long range electrostatic interactions. Lithium atom prefers to adsorbed on hollow site similar to other group-IV monolayers and the adsorption results in metallisation of GeC instead of semiconducting behaviour. Na and K adsorption can induce 1 ? total magnetic moment on GeC structures and they have shown semiconductor property which may have potential use in spintronic devices. We also showed that alkali or alkaline earth metal atoms can form dimer on GeC sheet. Calculated adsorption energies suggest that clustering of alkali and alkaline earth atoms is energetically favourable. All dimer adsorbed GeC systems have nonmagnetic semiconductor property with varying band gaps from 0.391 to 1.311 eV which are very suitable values for various device applications.

  17. Morphology and Orientation Selection of Non-metallic Inclusions in Electrified Molten Metal

    NASA Astrophysics Data System (ADS)

    Zhao, Z. C.; Qin, R. S.

    2017-10-01

    The effect of electric current on morphology and orientation selection of non-metallic inclusions in molten metal has been investigated using theoretical modeling and numerical calculation. Two geometric factors, namely the circularity ( fc ) and alignment ratio ( fe ) were introduced to describe the inclusions shape and configuration. Electric current free energy was calculated and the values were used to determine the thermodynamic preference between different microstructures. Electric current promotes the development of inclusion along the current direction by either expatiating directional growth or enhancing directional agglomeration. Reconfiguration of the inclusions to reduce the system electric resistance drives the phenomena. The morphology and orientation selection follow the routine to reduce electric free energy. The numerical results are in agreement with our experimental observations.

  18. Ab Initio Study of Chemical Reactions of Cold SrF and CaF Molecules with Alkali-Metal and Alkaline-Earth-Metal Atoms: The Implications for Sympathetic Cooling.

    PubMed

    Kosicki, Maciej Bartosz; Kędziera, Dariusz; Żuchowski, Piotr Szymon

    2017-06-01

    We investigate the energetics of the atom exchange reaction in the SrF + alkali-metal atom and CaF + alkali-metal atom systems. Such reactions are possible only for collisions of SrF and CaF with the lithium atoms, while they are energetically forbidden for other alkali-metal atoms. Specifically, we focus on SrF interacting with Li, Rb, and Sr atoms and use ab initio methods to demonstrate that the SrF + Li and SrF + Sr reactions are barrierless. We present potential energy surfaces for the interaction of the SrF molecule with the Li, Rb, and Sr atoms in their energetically lowest-lying electronic spin states. The obtained potential energy surfaces are deep and exhibit profound interaction anisotropies. We predict that the collisions of SrF molecules in the rotational or Zeeman excited states most likely have a strong inelastic character. We discuss the prospects for the sympathetic cooling of SrF and CaF molecules using ultracold alkali-metal atoms.

  19. Crown Ether Complexes of Alkali-Metal Chlorides from SO2.

    PubMed

    Reuter, Kirsten; Rudel, Stefan S; Buchner, Magnus R; Kraus, Florian; von Hänisch, Carsten

    2017-07-18

    The structures of alkali-metal chloride SO 2 solvates (Li-Cs) in conjunction with 12-crown-4 or 1,2-disila-12-crown-4 show strong discrepancies, despite the structural similarity of the ligands. Both types of crown ethers form 1:1 complexes with LiCl to give [Li(1,2-disila-12-crown-4)(SO 2 Cl)] (1) and [Li(12-crown-4)Cl]⋅4 SO 2 (2). However, 1,2-disila-12-crown-4 proved unable to coordinate cations too large for the cavity diameter, for example, by the formation of sandwich-type complexes. As a result, 12-crown-4 reacts exclusively with the heavier alkali-metal chlorides NaCl, KCl and RbCl. Compounds [Na(12-crown-4) 2 ]Cl⋅4 SO 2 (3) and [M(12-crown-4) 2 (SO 2 )]Cl⋅4 SO 2 (4: M=K; 5: M=Rb) all showed S-coordination to the chloride ions through four SO 2 molecules. Compounds 4 and 5 additionally exhibit the first crystallographically confirmed non-bridging O,O'-coordination mode of SO 2 . Unexpectedly, the disila-crown ether supports the dissolution of RbCl and CsCl in the solvent and gives the homoleptic SO 2 -solvated alkali-metal chlorides [MCl⋅3 SO 2 ] (6: M=Rb; 7: M=Cs), which incorporate bridging μ-O,O'-coordinating moieties and the unprecedented side-on O,O'-coordination mode. All compounds were characterised by single-crystal X-ray diffraction. The crown ether complexes were additionally studied by using NMR spectroscopy, and the presence of SO 2 at ambient temperature was revealed by IR spectroscopy of the neat compounds. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Electrolysis of a molten semiconductor

    PubMed Central

    Yin, Huayi; Chung, Brice; Sadoway, Donald R.

    2016-01-01

    Metals cannot be extracted by electrolysis of transition-metal sulfides because as liquids they are semiconductors, which exhibit high levels of electronic conduction and metal dissolution. Herein by introduction of a distinct secondary electrolyte, we reveal a high-throughput electro-desulfurization process that directly converts semiconducting molten stibnite (Sb2S3) into pure (99.9%) liquid antimony and sulfur vapour. At the bottom of the cell liquid antimony pools beneath cathodically polarized molten stibnite. At the top of the cell sulfur issues from a carbon anode immersed in an immiscible secondary molten salt electrolyte disposed above molten stibnite, thereby blocking electronic shorting across the cell. As opposed to conventional extraction practices, direct sulfide electrolysis completely avoids generation of problematic fugitive emissions (CO2, CO and SO2), significantly reduces energy consumption, increases productivity in a single-step process (lower capital and operating costs) and is broadly applicable to a host of electronically conductive transition-metal chalcogenides. PMID:27553525

  1. Electrolysis of a molten semiconductor

    DOE PAGES

    Yin, Huayi; Chung, Brice; Sadoway, Donald R.

    2016-08-24

    Metals cannot be extracted by electrolysis of transition-metal sulfides because as liquids they are semiconductors, which exhibit high levels of electronic conduction and metal dissolution. Herein by introduction of a distinct secondary electrolyte, we reveal a high-throughput electro-desulfurization process that directly converts semiconducting molten stibnite (Sb 2S 3) into pure (99.9%) liquid antimony and sulfur vapour. At the bottom of the cell liquid antimony pools beneath cathodically polarized molten stibnite. At the top of the cell sulfur issues from a carbon anode immersed in an immiscible secondary molten salt electrolyte disposed above molten stibnite, thereby blocking electronic shorting across themore » cell. In conclusion, as opposed to conventional extraction practices, direct sulfide electrolysis completely avoids generation of problematic fugitive emissions (CO 2, CO and SO 2), significantly reduces energy consumption, increases productivity in a single-step process (lower capital and operating costs) and is broadly applicable to a host of electronically conductive transition-metal chalcogenides.« less

  2. Electrolysis of a molten semiconductor.

    PubMed

    Yin, Huayi; Chung, Brice; Sadoway, Donald R

    2016-08-24

    Metals cannot be extracted by electrolysis of transition-metal sulfides because as liquids they are semiconductors, which exhibit high levels of electronic conduction and metal dissolution. Herein by introduction of a distinct secondary electrolyte, we reveal a high-throughput electro-desulfurization process that directly converts semiconducting molten stibnite (Sb2S3) into pure (99.9%) liquid antimony and sulfur vapour. At the bottom of the cell liquid antimony pools beneath cathodically polarized molten stibnite. At the top of the cell sulfur issues from a carbon anode immersed in an immiscible secondary molten salt electrolyte disposed above molten stibnite, thereby blocking electronic shorting across the cell. As opposed to conventional extraction practices, direct sulfide electrolysis completely avoids generation of problematic fugitive emissions (CO2, CO and SO2), significantly reduces energy consumption, increases productivity in a single-step process (lower capital and operating costs) and is broadly applicable to a host of electronically conductive transition-metal chalcogenides.

  3. Electrolysis of a molten semiconductor

    NASA Astrophysics Data System (ADS)

    Yin, Huayi; Chung, Brice; Sadoway, Donald R.

    2016-08-01

    Metals cannot be extracted by electrolysis of transition-metal sulfides because as liquids they are semiconductors, which exhibit high levels of electronic conduction and metal dissolution. Herein by introduction of a distinct secondary electrolyte, we reveal a high-throughput electro-desulfurization process that directly converts semiconducting molten stibnite (Sb2S3) into pure (99.9%) liquid antimony and sulfur vapour. At the bottom of the cell liquid antimony pools beneath cathodically polarized molten stibnite. At the top of the cell sulfur issues from a carbon anode immersed in an immiscible secondary molten salt electrolyte disposed above molten stibnite, thereby blocking electronic shorting across the cell. As opposed to conventional extraction practices, direct sulfide electrolysis completely avoids generation of problematic fugitive emissions (CO2, CO and SO2), significantly reduces energy consumption, increases productivity in a single-step process (lower capital and operating costs) and is broadly applicable to a host of electronically conductive transition-metal chalcogenides.

  4. Solid oxide membrane-assisted controllable electrolytic fabrication of metal carbides in molten salt.

    PubMed

    Zou, Xingli; Zheng, Kai; Lu, Xionggang; Xu, Qian; Zhou, Zhongfu

    2016-08-15

    Silicon carbide (SiC), titanium carbide (TiC), zirconium carbide (ZrC), and tantalum carbide (TaC) have been electrochemically produced directly from their corresponding stoichiometric metal oxides/carbon (MOx/C) precursors by electrodeoxidation in molten calcium chloride (CaCl2). An assembled yttria stabilized zirconia solid oxide membrane (SOM)-based anode was employed to control the electrodeoxidation process. The SOM-assisted controllable electrochemical process was carried out in molten CaCl2 at 1000 °C with a potential of 3.5 to 4.0 V. The reaction mechanism of the electrochemical production process and the characteristics of these produced metal carbides (MCs) were systematically investigated. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses clearly identify that SiC, TiC, ZrC, and TaC carbides can be facilely fabricated. SiC carbide can be controlled to form a homogeneous nanowire structure, while the morphologies of TiC, ZrC, and TaC carbides exhibit porous nodular structures with micro/nanoscale particles. The complex chemical/electrochemical reaction processes including the compounding, electrodeoxidation, dissolution-electrodeposition, and in situ carbonization processes in molten CaCl2 are also discussed. The present results preliminarily demonstrate that the molten salt-based SOM-assisted electrodeoxidation process has the potential to be used for the facile and controllable electrodeoxidation of MOx/C precursors to micro/nanostructured MCs, which can potentially be used for various applications.

  5. Cathode architectures for alkali metal / oxygen batteries

    DOEpatents

    Visco, Steven J; Nimon, Vitaliy; De Jonghe, Lutgard C; Volfkovich, Yury; Bograchev, Daniil

    2015-01-13

    Electrochemical energy storage devices, such as alkali metal-oxygen battery cells (e.g., non-aqueous lithium-air cells), have a cathode architecture with a porous structure and pore composition that is tailored to improve cell performance, especially as it pertains to one or more of the discharge/charge rate, cycle life, and delivered ampere-hour capacity. A porous cathode architecture having a pore volume that is derived from pores of varying radii wherein the pore size distribution is tailored as a function of the architecture thickness is one way to achieve one or more of the aforementioned cell performance improvements.

  6. Separation of Calcium Isotopes by Counter-Current Electro-Migration in Molten Salts; SEPARATION DES ISOTOPES DU CALCIUM PAR ELECTRO-MIGRATION A CONTRECOURANT EN SELS FONDUS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Menes, F.; Dirian, G.; Roth, E.

    1962-01-01

    The method of counter-current electromigration in molten salts was applied to CaBr/sub 2/ with an alkali metal bromide added to the cathode compartment. Enrichments on Ca/sup 46/ greater than a factor of two were obtained at the anode. The mass effect was found to be about 0.06. An estimation of the cost of energy for a process based on this method was made. (auth)

  7. Thermodynamic investigation of the effect of alkali metal impuries on the processing of aluminum and magnesium alloys

    NASA Astrophysics Data System (ADS)

    Zhang, Shengjun

    2006-12-01

    of aluminum and magnesium alloys. As the first step of the thermodynamic description of the high-order system, the constitutive-binary systems were modeled in the present work using the CALPHAD technique combined with first-principles calculations. Then, ternaries and higher order systems can be modeled. For ternary systems without experimental data, the thermodynamic description is extrapolated by combining three constitutive-binary systems. Alkali-metal induced high temperature embrittlement (HTE) and loss of ductility were investigated in Al-Li, Al-Mg and Mg-Li alloys. It was discovered that the alkali-metal-rich liquid-2 phase is the cause of HTE and the loss of ductility is proportional to the mole fraction of the liquid phase and the grain size. The calculated results are consistent with experimental observations in the literature and were used to determine HTE safe and sensitive zones, maximum and critical hot-rolling temperatures and the maximum allowable Na content in alloys, which can be used to industrial processing of Al and Mg alloys. The degree of HTE is proportional to the mole fraction of the liquid-2 phase and the grain size.

  8. An Assessment of Molten Metal Detachment Hazards for Electron Beam Welding in the Space Environment: Analysis and Test Results

    NASA Technical Reports Server (NTRS)

    Nunes, A. C., Jr.; Russell, C.; Bhat, B.; Fragomeni, J. M.

    1998-01-01

    Conditions under which molten metal detachments might occur in a space welding environment are analyzed. A weld pool detachment parameter specifying conditions for pool detachment by impact is derived and corroborated by experimental evidence. Impact detachment for the pool is unlikely. Impact detachment for a drop of metal on the end of the weld wire may be possible under extreme conditions. Other potential causes of molten metal detachment considered, vaporization pressure forces and wire flickout from the pool, did not appear to present significant detachment threats.

  9. Multiphysics Modeling for Dimensional Analysis of a Self-Heated Molten Regolith Electrolysis Reactor for Oxygen and Metals Production on the Moon and Mars

    NASA Technical Reports Server (NTRS)

    Dominguez, Jesus; Sibille, Laurent

    2010-01-01

    The technology of direct electrolysis of molten lunar regolith to produce oxygen and molten metal alloys has progressed greatly in the last few years. The development of long-lasting inert anodes and cathode designs as well as techniques for the removal of molten products from the reactor has been demonstrated. The containment of chemically aggressive oxide and metal melts is very difficult at the operating temperatures ca. 1600 C. Containing the molten oxides in a regolith shell can solve this technical issue and can be achieved by designing a self-heating reactor in which the electrolytic currents generate enough Joule heat to create a molten bath.

  10. A review of flexible lithium-sulfur and analogous alkali metal-chalcogen rechargeable batteries.

    PubMed

    Peng, Hong-Jie; Huang, Jia-Qi; Zhang, Qiang

    2017-08-29

    Flexible energy storage systems are imperative for emerging flexible devices that are revolutionizing our life. Lithium-ion batteries, the current main power sources, are gradually approaching their theoretical limitation in terms of energy density. Therefore, alternative battery chemistries are urgently required for next-generation flexible power sources with high energy densities, low cost, and inherent safety. Flexible lithium-sulfur (Li-S) batteries and analogous flexible alkali metal-chalcogen batteries are of paramount interest owing to their high energy densities endowed by multielectron chemistry. In this review, we summarized the recent progress of flexible Li-S and analogous batteries. A brief introduction to flexible energy storage systems and general Li-S batteries has been provided first. Progress in flexible materials for flexible Li-S batteries are reviewed subsequently, with a detailed classification of flexible sulfur cathodes as those based on carbonaceous (e.g., carbon nanotubes, graphene, and carbonized polymers) and composite (polymers and inorganics) materials and an overview of flexible lithium anodes and flexible solid-state electrolytes. Advancements in other flexible alkali metal-chalcogen batteries are then introduced. In the next part, we emphasize the importance of cell packaging and flexibility evaluation, and two special flexible battery prototypes of foldable and cable-type Li-S batteries are highlighted. In the end, existing challenges and future development of flexible Li-S and analogous alkali metal-chalcogen batteries are summarized and prospected.

  11. The Alkali Metal Thermal-To-Electric Converter for Solar System Exploration

    NASA Technical Reports Server (NTRS)

    Ryan, M.

    1999-01-01

    AMTEC, the Alkali Metal Thermal to Electric Converter, is a direct thermal to electric energy conversion device; it has been demostrated to perform at high power densities, with open circuit voltages in single electrochemical cells up to 1.6 V and current desities up to 2.0 A/cm(sup 2).

  12. Molybdenum cell for x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures

    NASA Astrophysics Data System (ADS)

    Matsuda, Kazuhiro; Tamura, Kozaburo; Katoh, Masahiro; Inui, Masanori

    2004-03-01

    We have developed a sample cell for x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures. All parts of the cell are made of molybdenum which is resistant to the chemical corrosion of alkali metals. Single crystalline molybdenum disks electrolytically thinned down to 40 μm were used as the walls of the cell through which x rays pass. The crystal orientation of the disks was controlled in order to reduce the background from the cell. All parts of the cell were assembled and brazed together using a high-temperature Ru-Mo alloy. Energy dispersive x-ray diffraction measurements have been successfully carried out for fluid rubidium up to 1973 K and 16.2 MPa. The obtained S(Q) demonstrates the applicability of the molybdenum cell to x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures.

  13. A study on optical properties of poly (ethylene oxide) based polymer electrolyte with different alkali metal iodides

    NASA Astrophysics Data System (ADS)

    Rao, B. Narasimha; Suvarna, R. Padma

    2016-05-01

    Polymer electrolytes were prepared by adding poly (ethylene glycol) dimethyl ether (PEGDME), TiO2 (nano filler), different alkali metal iodide salts RI (R+=Li+, Na+, K+, Rb+, Cs+) and I2 into Acetonitrile gelated with Poly (ethylene oxide) (PEO). Optical properties of poly (ethylene oxide) based polymer electrolytes were studied by FTIR, UV-Vis spectroscopic techniques. FTIR spectrum reveals that the alkali metal cations were coordinated to ether oxygen of PEO. The optical absorption studies were made in the wavelength range 200-800 nm. It is observed that the optical absorption increases with increase in the radius of alkali metal cation. The optical band gap for allowed direct transitions was evaluated using Urbach-edges method. The optical properties such as optical band gap, refractive index and extinction coefficient were determined. The studied polymer materials are useful for solar cells, super capacitors, fuel cells, gas sensors etc.

  14. Investigating the effects of alkali metal Na addition on catalytic activity of HZSM-5 for methyl mercaptan elimination

    NASA Astrophysics Data System (ADS)

    Yu, Jie; He, Dedong; Chen, Dingkai; Liu, Jiangping; Lu, Jichang; Liu, Feng; Liu, Pan; Zhao, Yutong; Xu, Zhizhi; Luo, Yongming

    2017-10-01

    Na-modified HZSM-5 catalysts with different Na loading amounts were prepared by incipient-wetness impregnation method and their catalytic activities for methyl mercaptan catalytic elimination were analyzed. XRD, N2 adsorption-desorption, NH3-TPD, CO2-TPD and FT-IR measurements were carried out to investigate the effects of modification of alkali metal Na on the physicochemical properties of the HZSM-5 zeolite catalyst. Research results illustrated that the introduction of alkali metal Na can improve catalytic activity for CH3SH catalytic elimination. CH3SH can be almost completely converted over 3%-Na/HZSM-5 at 450 °C compared to pure HZSM-5 at 600 °C based on our experimental results and the results from previous research. The improved catalytic activity could be attributed to the regulated acid-base properties of the HZSM-5 catalysts by doping with alkali metal Na. High alkali concentration treatment, however, may destroy the framework structure of the catalyst sample, thus causing the poor stability performance of the obtained catalyst.

  15. Compatibility of molten salts with advanced solar dynamic receiver materials

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.; Perry, W. D.

    1989-01-01

    Metal-coated graphite fibers are being considered as a thermal conductivity enhancement filler material for molten salts in solar dynamic thermal energy storage systems. The successful metal coating chosen for this application must exhibit acceptable wettability and must be compatible with the molten salt environment. Contact angle values between molten lithium fluoride and several metal, metal fluoride, and metal oxide substrates have been determined at 892 C using a modification of the Wilhelmy plate technique. Reproducible contact angles with repeated exposure to the molten LiF indicated compatibility.

  16. Element specificity of ortho-positronium annihilation for alkali-metal loaded SiO2 glasses.

    PubMed

    Sato, K; Hatta, T

    2015-03-07

    Momentum distributions associated with ortho-positronium (o-Ps) pick-off annihilation photon are often influenced by light elements, as, e.g., carbon, oxygen, and fluorine. This phenomenon, so-called element specificity of o-Ps pick-off annihilation, has been utilized for studying the elemental environment around the open spaces. To gain an insight into the element specificity of o-Ps pick-off annihilation, the chemical shift of oxygen 1s binding energy and the momentum distributions associated with o-Ps pick-off annihilation were systematically investigated for alkali-metal loaded SiO2 glasses by means of X-ray photoelectron spectroscopy and positron-age-momentum correlation spectroscopy, respectively. Alkali metals introduced into the open spaces surrounded by oxygen atoms cause charge transfer from alkali metals to oxygen atoms, leading to the lower chemical shift for the oxygen 1s binding energy. The momentum distribution of o-Ps localized into the open spaces is found to be closely correlated with the oxygen 1s chemical shift. This correlation with the deepest 1s energy level evidences that the element specificity of o-Ps originates from pick-off annihilation with orbital electrons, i.e., dominantly with oxygen 2p valence electrons and s electrons with lower probability.

  17. A Study of the Hydration of the Alkali Metal Ions in Aqueous Solution

    PubMed Central

    2011-01-01

    The hydration of the alkali metal ions in aqueous solution has been studied by large angle X-ray scattering (LAXS) and double difference infrared spectroscopy (DDIR). The structures of the dimethyl sulfoxide solvated alkali metal ions in solution have been determined to support the studies in aqueous solution. The results of the LAXS and DDIR measurements show that the sodium, potassium, rubidium and cesium ions all are weakly hydrated with only a single shell of water molecules. The smaller lithium ion is more strongly hydrated, most probably with a second hydration shell present. The influence of the rubidium and cesium ions on the water structure was found to be very weak, and it was not possible to quantify this effect in a reliable way due to insufficient separation of the O–D stretching bands of partially deuterated water bound to these metal ions and the O–D stretching bands of the bulk water. Aqueous solutions of sodium, potassium and cesium iodide and cesium and lithium hydroxide have been studied by LAXS and M–O bond distances have been determined fairly accurately except for lithium. However, the number of water molecules binding to the alkali metal ions is very difficult to determine from the LAXS measurements as the number of distances and the temperature factor are strongly correlated. A thorough analysis of M–O bond distances in solid alkali metal compounds with ligands binding through oxygen has been made from available structure databases. There is relatively strong correlation between M–O bond distances and coordination numbers also for the alkali metal ions even though the M–O interactions are weak and the number of complexes of potassium, rubidium and cesium with well-defined coordination geometry is very small. The mean M–O bond distance in the hydrated sodium, potassium, rubidium and cesium ions in aqueous solution have been determined to be 2.43(2), 2.81(1), 2.98(1) and 3.07(1) Å, which corresponds to six-, seven-, eight- and

  18. Alkali-metal silicate binders and methods of manufacture

    NASA Technical Reports Server (NTRS)

    Schutt, J. B. (Inventor)

    1979-01-01

    A paint binder is described which uses a potassium or sodium silicate dispersion having a silicon dioxide to alkali-metal oxide mol ratio of from 4.8:1 to 6.0:1. The binder exhibits stability during both manufacture and storage. The process of making the binder is predictable and repeatable and the binder may be made with inexpensive components. The high mol ratio is achieved with the inclusion of a silicon dioxide hydrogel. The binder, which also employs a silicone, is in the final form of a hydrogel sol.

  19. 30 CFR 56.15007 - Protective equipment or clothing for welding, cutting, or working with molten metal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protective equipment or clothing for welding... METAL AND NONMETAL MINES Personal Protection § 56.15007 Protective equipment or clothing for welding... be worn when welding, cutting, or working with molten metal. ...

  20. 30 CFR 56.15007 - Protective equipment or clothing for welding, cutting, or working with molten metal.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Protective equipment or clothing for welding... METAL AND NONMETAL MINES Personal Protection § 56.15007 Protective equipment or clothing for welding... be worn when welding, cutting, or working with molten metal. ...

  1. 30 CFR 56.15007 - Protective equipment or clothing for welding, cutting, or working with molten metal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Protective equipment or clothing for welding... METAL AND NONMETAL MINES Personal Protection § 56.15007 Protective equipment or clothing for welding... be worn when welding, cutting, or working with molten metal. ...

  2. 30 CFR 56.15007 - Protective equipment or clothing for welding, cutting, or working with molten metal.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Protective equipment or clothing for welding... METAL AND NONMETAL MINES Personal Protection § 56.15007 Protective equipment or clothing for welding... be worn when welding, cutting, or working with molten metal. ...

  3. 30 CFR 56.15007 - Protective equipment or clothing for welding, cutting, or working with molten metal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Protective equipment or clothing for welding... METAL AND NONMETAL MINES Personal Protection § 56.15007 Protective equipment or clothing for welding... be worn when welding, cutting, or working with molten metal. ...

  4. Alkali or alkaline earth metal promoted catalyst and a process for methanol synthesis using alkali or alkaline earth metals as promoters

    DOEpatents

    Tierney, J.W.; Wender, I.; Palekar, V.M.

    1995-01-31

    The present invention relates to a novel route for the synthesis of methanol, and more specifically to the production of methanol by contacting synthesis gas under relatively mild conditions in a slurry phase with a heterogeneous catalyst comprising reduced copper chromite impregnated with an alkali or alkaline earth metal. There is thus no need to add a separate alkali or alkaline earth compound. The present invention allows the synthesis of methanol to occur in the temperature range of approximately 100--160 C and the pressure range of 40--65 atm. The process produces methanol with up to 90% syngas conversion per pass and up to 95% methanol selectivity. The only major by-product is a small amount of easily separated methyl formate. Very small amounts of water, carbon dioxide and dimethyl ether are also produced. The present catalyst combination also is capable of tolerating fluctuations in the H[sub 2]/CO ratio without major deleterious effect on the reaction rate. Furthermore, carbon dioxide and water are also tolerated without substantial catalyst deactivation.

  5. Alkali or alkaline earth metal promoted catalyst and a process for methanol synthesis using alkali or alkaline earth metals as promoters

    DOEpatents

    Tierney, John W.; Wender, Irving; Palekar, Vishwesh M.

    1995-01-01

    The present invention relates to a novel route for the synthesis of methanol, and more specifically to the production of methanol by contacting synthesis gas under relatively mild conditions in a slurry phase with a heterogeneous catalyst comprising reduced copper chromite impregnated with an alkali or alkaline earth metal. There is thus no need to add a separate alkali or alkaline earth compound. The present invention allows the synthesis of methanol to occur in the temperature range of approximately 100.degree.-160.degree. C. and the pressure range of 40-65 atm. The process produces methanol with up to 90% syngas conversion per pass and up to 95% methanol selectivity. The only major by-product is a small amount of easily separated methyl formate. Very small amounts of water, carbon dioxide and dimethyl ether are also produced. The present catalyst combination also is capable of tolerating fluctuations in the H.sub.2 /CO ratio without major deleterious effect on the reaction rate. Furthermore, carbon dioxide and water are also tolerated without substantial catalyst deactivation.

  6. Cathode composition for electrochemical cell

    DOEpatents

    Steunenberg, Robert K.; Martin, Allan E.; Tomczuk, Zygmunt

    1976-01-01

    A high-temperature, secondary electrochemical cell includes a negative electrode containing an alkali metal such as lithium, an electrolyte of molten salt containing ions of that alkali metal and a positive electrode containing a mixture of metallic sulfides. The positive electrode composition is contained within a porous structure that permits permeation of molten electrolyte and includes a mixture of about 5% to 30% by weight Cu.sub.2 S in FeS.

  7. MOLTEN FLUORIDE NUCLEAR REACTOR FUEL

    DOEpatents

    Barton, C.J.; Grimes, W.R.

    1960-01-01

    Molten-salt reactor fuel compositions consisting of mixtures of fluoride salts are reported. In its broadest form, the composition contains an alkali fluoride such as sodium fluoride, zirconium tetrafluoride, and a uranium fluoride, the latter being the tetrafluoride or trifluoride or a mixture of the two. An outstanding property of these fuel compositions is a high coeffieient of thermal expansion which provides a negative temperature coefficient of reactivity in reactors in which they are used.

  8. Oxidation behavior of Cr(III) during thermal treatment of chromium hydroxide in the presence of alkali and alkaline earth metal chlorides.

    PubMed

    Mao, Linqiang; Gao, Bingying; Deng, Ning; Liu, Lu; Cui, Hao

    2016-02-01

    The oxidation behavior of Cr(III) during the thermal treatment of chromium hydroxide in the presence of alkali and alkaline earth metal chlorides (NaCl, KCl, MgCl2, and CaCl2) was investigated. The amounts of Cr(III) oxidized at various temperatures and heating times were determined, and the Cr-containing species in the residues were characterized. During the transformation of chromium hydroxide to Cr2O3 at 300 °C approximately 5% of the Cr(III) was oxidized to form intermediate compounds containing Cr(VI) (i.e., CrO3), but these intermediates were reduced to Cr2O3 when the temperature was above 400 °C. Alkali and alkaline earth metals significantly promoted the oxidation of Cr(III) during the thermal drying process. Two pathways were involved in the influences the alkali and alkaline earth metals had on the formation of Cr(VI). In pathway I, the alkali and alkaline earth metals were found to act as electron transfer agents and to interfere with the dehydration process, causing more intermediate Cr(VI)-containing compounds (which were identified as being CrO3 and Cr5O12) to be formed. The reduction of intermediate compounds to Cr2O3 was also found to be hindered in pathway I. In pathway II, the alkali and alkaline earth metals were found to contribute to the oxidation of Cr(III) to form chromates. The results showed that the presence of alkali and alkaline earth metals significantly increases the degree to which Cr(III) is oxidized during the thermal drying of chromium-containing sludge. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. pH tunability and influence of alkali metal basicity on the plasmonic resonance of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Yadav, Vijay D.; Akhil Krishnan, R.; Borade, Lalit; Shirolikar, Seema; Jain, Ratnesh; Dandekar, Prajakta

    2017-07-01

    Localized surface plasmon resonance has been a unique and intriguing feature of silver nanoparticles (AgNPs) that has attracted immense attention. This has led to an array of applications for AgNPs in optics, sensors, plasmonic imaging etc. Although numerous applications have been reported consistently, the importance of buffer and reaction parameters during the synthesis of AgNPs, is still unclear. In the present study, we have demonstrated the influence of parameters like pH, temperature and buffer conditions (0.1 M citrate buffer) on the plasmonic resonance of AgNPs. We found that neutral and basic pH (from alkali metal) provide optimum interaction conditions for nucleation of plasmon resonant AgNPs. Interestingly, this was not observed in the non-alkali metal base (ammonia). Also, when the nanoparticles synthesized from alkali metal base were incorporated in different buffers, it was observed that the nanoparticles dissolved in the acidic buffer and had reduced plasmonic resonance intensity. This, however, was resolved in the basic buffer, increasing the plasmonic resonance intensity and confirming that nucleation of nanoparticles required basic conditions. The above inference has been supported by characterization of AgNPs using UV-Vis spectrophotometer, Fluorimetry analysis, Infrared spectrometer and TEM analysis. The study concluded that the plasmonic resonance of AgNPs occurs due to the interaction of alkali (Na) and transition metal (Ag) salt in basic/neutral conditions, at a specific temperature range, in presence of a capping agent (citric acid), providing a pH tune to the overall system.

  10. Treatment of halogen-containing waste and other waste materials

    DOEpatents

    Forsberg, Charles W.; Beahm, Edward C.; Parker, George W.

    1997-01-01

    A process for treating a halogen-containing waste material. The process provides a bath of molten glass containing a sacrificial metal oxide capable of reacting with a halogen in the waste material. The sacrificial metal oxide is present in the molten glass in at least a stoichiometric amount with respect to the halogen in the waste material. The waste material is introduced into the bath of molten glass to cause a reaction between the halogen in the waste material and the sacrificial metal oxide to yield a metal halide. The metal halide is a gas at the temperature of the molten glass. The gaseous metal halide is separated from the molten glass and contacted with an aqueous scrubber solution of an alkali metal hydroxide to yield a metal hydroxide or metal oxide-containing precipitate and a soluble alkali metal halide. The precipitate is then separated from the aqueous scrubber solution. The molten glass containing the treated waste material is removed from the bath as a waste glass. The process of the invention can be used to treat all types of waste material including radioactive wastes. The process is particularly suited for separating halogens from halogen-containing wastes.

  11. Metals Electroprocessing in Molten Salts

    NASA Technical Reports Server (NTRS)

    Sadoway, D. R.

    1985-01-01

    The present study seeks to explain the poor quality of solid electrodeposits in molten salts through a consideration of the effects of fluid flow of the electrolyte. Transparent cells allow observation of electrolyte circulation by a laser schlieren optical technique during the electrodeposition of solid zinc from the molten salt electrolyte, ZnCl2 - LiCl-KCl. Experimental variables are current, density, electrolyte composition, and cell geometry. Based on the results of earlier electrodeposition studies as well as reports in the literature, these parameters are identified as having the primary influence on cell performance and deposit quality. Experiments are conducted to measure the fluid flow patterns and the electrochemical cell characteristics, and to correlate this information with the morphology of the solid electrodeposit produced. Specifically, cell voltage, cell current, characteristic time for dendrite evolution, and dendrite growth directions are noted. Their relationship to electrolyte flow patterns and the morphology of the resulting electrodeposit are derived. Results to date indicate that laser schlieren imaging is capable of revealing fluid flow patterns in a molten salt electrolyte.

  12. Induction slag reduction process for purifying metals

    DOEpatents

    Traut, Davis E.; Fisher, II, George T.; Hansen, Dennis A.

    1991-01-01

    A continuous method is provided for purifying and recovering transition metals such as neodymium and zirconium that become reactive at temperatures above about 500.degree. C. that comprises the steps of contacting the metal ore with an appropriate fluorinating agent such as an alkaline earth metal fluosilicate to form a fluometallic compound, and reducing the fluometallic compound with a suitable alkaline earth or alkali metal compound under molten conditions, such as provided in an induction slag metal furnace. The method of the invention is advantageous in that it is simpler and less expensive than methods used previously to recover pure metals, and it may be employed with a wide range of transition metals that were reactive with enclosures used in the prior art methods and were hard to obtain in uncontaminated form.

  13. Feet sunk in molten aluminium: The burn and its prevention.

    PubMed

    Alonso-Peña, David; Arnáiz-García, María Elena; Valero-Gasalla, Javier Luis; Arnáiz-García, Ana María; Campillo-Campaña, Ramón; Alonso-Peña, Javier; González-Santos, Jose María; Fernández-Díaz, Alaska Leonor; Arnáiz, Javier

    2015-08-01

    Nowadays, despite improvements in safety rules and inspections in the metal industry, foundry workers are not free from burn accidents. Injuries caused by molten metals include burns secondary to molten iron, aluminium, zinc, copper, brass, bronze, manganese, lead and steel. Molten aluminium is one of the most common causative agents of burns (60%); however, only a few publications exist concerning injuries from molten aluminium. The main mechanisms of lesion from molten aluminium include direct contact of the molten metal with the skin or through safety apparel, or when the metal splash burns through the pants and rolls downward along the leg. Herein, we report three cases of deep dermal burns after 'soaking' the foot in liquid aluminium and its evolutive features. This paper aims to show our experience in the management of burns due to molten aluminium. We describe the current management principles and the key features of injury prevention. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

  14. Electronic and structural ground state of heavy alkali metals at high pressure

    DOE PAGES

    Fabbris, G.; Lim, J.; Veiga, L. S. I.; ...

    2015-02-17

    Here, alkali metals display unexpected properties at high pressure, including emergence of low symmetry crystal structures, that appear to occur due to enhanced electronic correlations among the otherwise nearly-free conduction electrons. We investigate the high pressure electronic and structural ground state of K, Rb, and Cs using x-ray absorption spectroscopy and x-ray diffraction measurements together with ab initio theoretical calculations. The sequence of phase transitions under pressure observed at low temperature is similar in all three heavy alkalis except for the absence of the oC84 phase in Cs. Both the experimental and theoretical results point to pressure-enhanced localization of themore » valence electrons characterized by pseudo-gap formation near the Fermi level and strong spd hybridization. Although the crystal structures predicted to host magnetic order in K are not observed, the localization process appears to drive these alkalis closer to a strongly correlated electron state.« less

  15. Electronic and structural ground state of heavy alkali metals at high pressure

    NASA Astrophysics Data System (ADS)

    Fabbris, G.; Lim, J.; Veiga, L. S. I.; Haskel, D.; Schilling, J. S.

    2015-02-01

    Alkali metals display unexpected properties at high pressure, including emergence of low-symmetry crystal structures, which appear to occur due to enhanced electronic correlations among the otherwise nearly free conduction electrons. We investigate the high-pressure electronic and structural ground state of K, Rb, and Cs using x-ray absorption spectroscopy and x-ray diffraction measurements together with a b i n i t i o theoretical calculations. The sequence of phase transitions under pressure observed at low temperature is similar in all three heavy alkalis except for the absence of the o C 84 phase in Cs. Both the experimental and theoretical results point to pressure-enhanced localization of the valence electrons characterized by pseudogap formation near the Fermi level and strong s p d hybridization. Although the crystal structures predicted to host magnetic order in K are not observed, the localization process appears to drive these alkalis closer to a strongly correlated electron state.

  16. Solvation Effect on Complexation of Alkali Metal Cations by a Calix[4]arene Ketone Derivative.

    PubMed

    Požar, Josip; Nikšić-Franjić, Ivana; Cvetnić, Marija; Leko, Katarina; Cindro, Nikola; Pičuljan, Katarina; Borilović, Ivana; Frkanec, Leo; Tomišić, Vladislav

    2017-09-14

    The medium effect on the complexation of alkali metal cations with a calix[4]arene ketone derivative (L) was systematically examined in methanol, ethanol, N-methylformamide, N,N-dimethylformamide, dimethyl sulfoxide, and acetonitrile. In all solvents the binding of Na + cation by L was rather efficient, whereas the complexation of other alkali metal cations was observed only in methanol and acetonitrile. Complexation reactions were enthalpically controlled, while ligand dissolution was endothermic in all cases. A notable influence of the solvent on NaL + complex stability could be mainly attributed to the differences in complexation entropies. The higher NaL + stability in comparison to complexes with other alkali metal cations in acetonitrile was predominantly due to a more favorable complexation enthalpy. The 1 H NMR investigations revealed a relatively low affinity of the calixarene sodium complex for inclusion of the solvent molecule in the calixarene hydrophobic cavity, with the exception of acetonitrile. Differences in complex stabilities in the explored solvents, apart from N,N-dimethylformamide and acetonitrile, could be mostly explained by taking into account solely the cation and complex solvation. A considerable solvent effect on the complexation equilibria was proven to be due to an interesting interplay between the transfer enthalpies and entropies of the reactants and the complexes formed.

  17. Density functional theory based screening of ternary alkali-transition metal borohydrides: A computational material design project

    NASA Astrophysics Data System (ADS)

    Hummelshøj, J. S.; Landis, D. D.; Voss, J.; Jiang, T.; Tekin, A.; Bork, N.; Dułak, M.; Mortensen, J. J.; Adamska, L.; Andersin, J.; Baran, J. D.; Barmparis, G. D.; Bell, F.; Bezanilla, A. L.; Bjork, J.; Björketun, M. E.; Bleken, F.; Buchter, F.; Bürkle, M.; Burton, P. D.; Buus, B. B.; Calborean, A.; Calle-Vallejo, F.; Casolo, S.; Chandler, B. D.; Chi, D. H.; Czekaj, I.; Datta, S.; Datye, A.; DeLaRiva, A.; Despoja, V.; Dobrin, S.; Engelund, M.; Ferrighi, L.; Frondelius, P.; Fu, Q.; Fuentes, A.; Fürst, J.; García-Fuente, A.; Gavnholt, J.; Goeke, R.; Gudmundsdottir, S.; Hammond, K. D.; Hansen, H. A.; Hibbitts, D.; Hobi, E.; Howalt, J. G.; Hruby, S. L.; Huth, A.; Isaeva, L.; Jelic, J.; Jensen, I. J. T.; Kacprzak, K. A.; Kelkkanen, A.; Kelsey, D.; Kesanakurthi, D. S.; Kleis, J.; Klüpfel, P. J.; Konstantinov, I.; Korytar, R.; Koskinen, P.; Krishna, C.; Kunkes, E.; Larsen, A. H.; Lastra, J. M. G.; Lin, H.; Lopez-Acevedo, O.; Mantega, M.; Martínez, J. I.; Mesa, I. N.; Mowbray, D. J.; Mýrdal, J. S. G.; Natanzon, Y.; Nistor, A.; Olsen, T.; Park, H.; Pedroza, L. S.; Petzold, V.; Plaisance, C.; Rasmussen, J. A.; Ren, H.; Rizzi, M.; Ronco, A. S.; Rostgaard, C.; Saadi, S.; Salguero, L. A.; Santos, E. J. G.; Schoenhalz, A. L.; Shen, J.; Smedemand, M.; Stausholm-Møller, O. J.; Stibius, M.; Strange, M.; Su, H. B.; Temel, B.; Toftelund, A.; Tripkovic, V.; Vanin, M.; Viswanathan, V.; Vojvodic, A.; Wang, S.; Wellendorff, J.; Thygesen, K. S.; Rossmeisl, J.; Bligaard, T.; Jacobsen, K. W.; Nørskov, J. K.; Vegge, T.

    2009-07-01

    We present a computational screening study of ternary metal borohydrides for reversible hydrogen storage based on density functional theory. We investigate the stability and decomposition of alloys containing 1 alkali metal atom, Li, Na, or K (M1); and 1 alkali, alkaline earth or 3d/4d transition metal atom (M2) plus two to five (BH4)- groups, i.e., M1M2(BH4)2-5, using a number of model structures with trigonal, tetrahedral, octahedral, and free coordination of the metal borohydride complexes. Of the over 700 investigated structures, about 20 were predicted to form potentially stable alloys with promising decomposition energies. The M1(Al/Mn/Fe)(BH4)4, (Li/Na)Zn(BH4)3, and (Na/K)(Ni/Co)(BH4)3 alloys are found to be the most promising, followed by selected M1(Nb/Rh)(BH4)4 alloys.

  18. Molten salt bath circulation design for an electrolytic cell

    DOEpatents

    Dawless, Robert K.; LaCamera, Alfred F.; Troup, R. Lee; Ray, Siba P.; Hosler, Robert B.

    1999-01-01

    An electrolytic cell for reduction of a metal oxide to a metal and oxygen has an inert anode and an upwardly angled roof covering the inert mode. The angled roof diverts oxygen bubbles into an upcomer channel, thereby agitating a molten salt bath in the upcomer channel and improving dissolution of a metal oxide in the molten salt bath. The molten salt bath has a lower velocity adjacent the inert anode in order to minimize corrosion by substances in the bath. A particularly preferred cell produces aluminum by electrolysis of alumina in a molten salt bath containing aluminum fluoride and sodium fluoride.

  19. Yarrowia lipolytica possesses two plasma membrane alkali metal cation/H+ antiporters with different functions in cell physiology.

    PubMed

    Papouskova, Klara; Sychrova, Hana

    2006-04-03

    The family of Nha antiporters mediating the efflux of alkali metal cations in exchange for protons across the plasma membrane is conserved in all yeast species. Yarrowia lipolytica is a dimorphic yeast, phylogenetically very distant from the model yeast Saccharomyces cerevisiae. A search in its sequenced genome revealed two genes (designated as YlNHA1 and YlNHA2) with homology to the S. cerevisiae NHA1 gene, which encodes a plasma membrane alkali metal cation/H+ antiporter. Upon heterologous expression of both YlNHA genes in S. cerevisiae, we showed that Y. lipolytica antiporters differ not only in length and sequence, but also in their affinity for individual substrates. While the YlNha1 protein mainly increased cell tolerance to potassium, YlNha2p displayed a remarkable transport capacity for sodium. Thus, Y. lipolytica is the first example of a yeast species with two plasma membrane alkali metal cation/H+ antiporters differing in their putative functions in cell physiology; cell detoxification vs. the maintenance of stable intracellular pH, potassium content and cell volume.

  20. Alkali activation of recovered fuel-biofuel fly ash from fluidised-bed combustion: Stabilisation/solidification of heavy metals.

    PubMed

    Yliniemi, Juho; Pesonen, Janne; Tiainen, Minna; Illikainen, Mirja

    2015-09-01

    Recovered fuel-biofuel fly ash from a fluidized bed boiler was alkali-activated and granulated with a sodium-silicate solution in order to immobilise the heavy metals it contains. The effect of blast-furnace slag and metakaolin as co-binders were studied. Leaching standard EN 12457-3 was applied to evaluate the immobilisation potential. The results showed that Ba, Pb and Zn were effectively immobilised. However, there was increased leaching after alkali activation for As, Cu, Mo, Sb and V. The co-binders had minimal or even negative effect on the immobilisation. One exception was found for Cr, in which the slag decreased leaching, and one was found for Cu, in which the slag increased leaching. A sequential leaching procedure was utilized to gain a deeper understanding of the immobilisation mechanism. By using a sequential leaching procedure it is possible fractionate elements into watersoluble, acid-soluble, easily-reduced and oxidisable fractions, yielding a total 'bioavailable' amount that is potentially hazardous for the environment. It was found that the total bioavailable amount was lower following alkali activation for all heavy metals, although the water-soluble fraction was higher for some metals. Evidence from leaching tests suggests the immobilisation mechanism was chemical retention, or trapping inside the alkali activation reaction products, rather than physical retention, adsorption or precipitation as hydroxides. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Oxygen redox chemistry without excess alkali-metal ions in Na2/3[Mg0.28Mn0.72]O2.

    PubMed

    Maitra, Urmimala; House, Robert A; Somerville, James W; Tapia-Ruiz, Nuria; Lozano, Juan G; Guerrini, Niccoló; Hao, Rong; Luo, Kun; Jin, Liyu; Pérez-Osorio, Miguel A; Massel, Felix; Pickup, David M; Ramos, Silvia; Lu, Xingye; McNally, Daniel E; Chadwick, Alan V; Giustino, Feliciano; Schmitt, Thorsten; Duda, Laurent C; Roberts, Matthew R; Bruce, Peter G

    2018-03-01

    The search for improved energy-storage materials has revealed Li- and Na-rich intercalation compounds as promising high-capacity cathodes. They exhibit capacities in excess of what would be expected from alkali-ion removal/reinsertion and charge compensation by transition-metal (TM) ions. The additional capacity is provided through charge compensation by oxygen redox chemistry and some oxygen loss. It has been reported previously that oxygen redox occurs in O 2p orbitals that interact with alkali ions in the TM and alkali-ion layers (that is, oxygen redox occurs in compounds containing Li + -O(2p)-Li + interactions). Na 2/3 [Mg 0.28 Mn 0.72 ]O 2 exhibits an excess capacity and here we show that this is caused by oxygen redox, even though Mg 2+ resides in the TM layers rather than alkali-metal (AM) ions, which demonstrates that excess AM ions are not required to activate oxygen redox. We also show that, unlike the alkali-rich compounds, Na 2/3 [Mg 0.28 Mn 0.72 ]O 2 does not lose oxygen. The extraction of alkali ions from the alkali and TM layers in the alkali-rich compounds results in severely underbonded oxygen, which promotes oxygen loss, whereas Mg 2+ remains in Na 2/3 [Mg 0.28 Mn 0.72 ]O 2 , which stabilizes oxygen.

  2. Oxygen redox chemistry without excess alkali-metal ions in Na2/3[Mg0.28Mn0.72]O2

    NASA Astrophysics Data System (ADS)

    Maitra, Urmimala; House, Robert A.; Somerville, James W.; Tapia-Ruiz, Nuria; Lozano, Juan G.; Guerrini, Niccoló; Hao, Rong; Luo, Kun; Jin, Liyu; Pérez-Osorio, Miguel A.; Massel, Felix; Pickup, David M.; Ramos, Silvia; Lu, Xingye; McNally, Daniel E.; Chadwick, Alan V.; Giustino, Feliciano; Schmitt, Thorsten; Duda, Laurent C.; Roberts, Matthew R.; Bruce, Peter G.

    2018-03-01

    The search for improved energy-storage materials has revealed Li- and Na-rich intercalation compounds as promising high-capacity cathodes. They exhibit capacities in excess of what would be expected from alkali-ion removal/reinsertion and charge compensation by transition-metal (TM) ions. The additional capacity is provided through charge compensation by oxygen redox chemistry and some oxygen loss. It has been reported previously that oxygen redox occurs in O 2p orbitals that interact with alkali ions in the TM and alkali-ion layers (that is, oxygen redox occurs in compounds containing Li+-O(2p)-Li+ interactions). Na2/3[Mg0.28Mn0.72]O2 exhibits an excess capacity and here we show that this is caused by oxygen redox, even though Mg2+ resides in the TM layers rather than alkali-metal (AM) ions, which demonstrates that excess AM ions are not required to activate oxygen redox. We also show that, unlike the alkali-rich compounds, Na2/3[Mg0.28Mn0.72]O2 does not lose oxygen. The extraction of alkali ions from the alkali and TM layers in the alkali-rich compounds results in severely underbonded oxygen, which promotes oxygen loss, whereas Mg2+ remains in Na2/3[Mg0.28Mn0.72]O2, which stabilizes oxygen.

  3. Theoretical analysis of oxygen diffusion at startup in an alkali metal heat pipe with gettered alloy walls

    NASA Technical Reports Server (NTRS)

    Tower, L. K.

    1973-01-01

    The diffusion of oxygen into, or out of, a gettered alloy exposed to oxygenated alkali liquid metal coolant, a situation arising in some high temperature heat transfer systems, was analyzed. The relation between the diffusion process and the thermochemistry of oxygen in the alloy and in the alkali metal was developed by making several simplifying assumptions. The treatment is therefore theoretical in nature. However, a practical example pertaining to the startup of a heat pipe with walls of T-111, a tantalum alloy, and lithium working fluid illustrates the use of the figures contained in the analysis.

  4. Mechanical properties of 4d transition metals in molten state

    NASA Astrophysics Data System (ADS)

    Singh, Deobrat; Sonvane, Yogesh; Thakor, P. B.

    2016-05-01

    Mechanical properties of 4d transition metals in molten state have been studied in the present study. We have calculated mechanical properties such as isothermal bulk modulus (B), modulus of rigidity (G), Young's modulus (Y) and Hardness have also been calculated from the elastic part of the Phonon dispersion curve (PDC). To describe the structural information, we have used different structure factor S(q) using Percus-Yevick hard sphere (PYHS) reference systems along with our newly constructed parameter free model potential.To see the influence of exchange and correlation effect on the above said properties of 3d liquid transition metals, we have used Sarkar et al (S)local field correction functions. Present results have been found good in agreement with available experimental data.

  5. Advances in Molten Oxide Electrolysis for the Production of Oxygen and Metals from Lunar Regolith

    NASA Technical Reports Server (NTRS)

    Sadoway, Donald R.; Sirk, Aislinn; Sibille, Laurent; Melendez, Orlando; Lueck, Dale; Curreri, Peter; Dominquez, Jesus; Whitlow, Jonathan

    2008-01-01

    As part of an In-Situ Resource Utilization infrastructure to sustain long term-human presence on the lunar surface, the production of oxygen and metals by electrolysis of lunar regolith has been the subject of major scrutiny. There is a reasonably large body of literature characterizing the candidate solvent electrolytes, including ionic liquids, molten salts, fluxed oxides, and pure molten regolith itself. In the light of this information and in consideration of available electrolytic technologies, the authors have determined that direct molten oxide electrolysis at temperatures of approx 1600 C is the most promising avenue for further development. Results from ongoing studies as well as those of previous workers will be presented. Topics include materials selection and testing, electrode stability, gas capture and analysis, and cell operation during feeding and tapping.

  6. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan. Revision 1

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None

    The Hanford Site, located northwest of the city of Richland, Washington, houses reactors, chemical-separation systems, and related facilities used for the production of special nuclear materials, as well as for activities associated with nuclear energy development. The 300 Area of the Hanford Site contains reactor fuel manufacturing facilities and several research and development laboratories. The 3718-F Alkali Metal Treatment and Storage Facility (3718-F Facility), located in the 300 Area, was used to store and treat alkali metal wastes. Therefore, it is subject to the regulatory requirements for the storage and treatment of dangerous wastes. Closure will be conducted pursuant tomore » the requirements of the Washington Administrative Code (WAC) 173-303-610 (Ecology 1989) and 40 CFR 270.1. Closure also will satisfy the thermal treatment facility closure requirements of 40 CFR 265.381. This closure plan presents a description of the 3718-F Facility, the history of wastes managed, and the approach that will be followed to close the facility. Only hazardous constituents derived from 3718-F Facility operations will be addressed.« less

  7. Molten salt bath circulation design for an electrolytic cell

    DOEpatents

    Dawless, R.K.; LaCamera, A.F.; Troup, R.L.; Ray, S.P.; Hosler, R.B.

    1999-08-17

    An electrolytic cell for reduction of a metal oxide to a metal and oxygen has an inert anode and an upwardly angled roof covering the inert mode. The angled roof diverts oxygen bubbles into an upcomer channel, thereby agitating a molten salt bath in the upcomer channel and improving dissolution of a metal oxide in the molten salt bath. The molten salt bath has a lower velocity adjacent the inert anode in order to minimize corrosion by substances in the bath. A particularly preferred cell produces aluminum by electrolysis of alumina in a molten salt bath containing aluminum fluoride and sodium fluoride. 4 figs.

  8. Radioisotope powered alkali metal thermoelectric converter design for space systems

    NASA Technical Reports Server (NTRS)

    Sievers, R. K.; Bankston, C. P.

    1988-01-01

    The design concept of an alkali-metal thermoelectric converter (AMTEC) for 15-30-percent-efficient conversion of heat from the General Purpose (radioisotope) Heat Source (GPHS) on spacecraft is presented. The basic physical principles of the conversion cycle are outlined; a theoretical model is derived; a modular design is described and illustrated with drawings; and the overall AMTEC/GPHS system design is characterized. Predicted performance data are presented in extensive tables and graphs and discussed in detail.

  9. Treatment of halogen-containing waste and other waste materials

    DOEpatents

    Forsberg, C.W.; Beahm, E.C.; Parker, G.W.

    1997-03-18

    A process is described for treating a halogen-containing waste material. The process provides a bath of molten glass containing a sacrificial metal oxide capable of reacting with a halogen in the waste material. The sacrificial metal oxide is present in the molten glass in at least a stoichiometric amount with respect to the halogen in the waste material. The waste material is introduced into the bath of molten glass to cause a reaction between the halogen in the waste material and the sacrificial metal oxide to yield a metal halide. The metal halide is a gas at the temperature of the molten glass. The gaseous metal halide is separated from the molten glass and contacted with an aqueous scrubber solution of an alkali metal hydroxide to yield a metal hydroxide or metal oxide-containing precipitate and a soluble alkali metal halide. The precipitate is then separated from the aqueous scrubber solution. The molten glass containing the treated waste material is removed from the bath as a waste glass. The process of the invention can be used to treat all types of waste material including radioactive wastes. The process is particularly suited for separating halogens from halogen-containing wastes. 3 figs.

  10. In Situ Solid-Gas Reactivity of Nanoscaled Metal Borides from Molten Salt Synthesis.

    PubMed

    Gouget, Guillaume; Debecker, Damien P; Kim, Ara; Olivieri, Giorgia; Gallet, Jean-Jacques; Bournel, Fabrice; Thomas, Cyril; Ersen, Ovidiu; Moldovan, Simona; Sanchez, Clément; Carenco, Sophie; Portehault, David

    2017-08-07

    Metal borides have mostly been studied as bulk materials. The nanoscale provides new opportunities to investigate the properties of these materials, e.g., nanoscale hardening and surface reactivity. Metal borides are often considered stable solids because of their covalent character, but little is known on their behavior under a reactive atmosphere, especially reductive gases. We use molten salt synthesis at 750 °C to provide cobalt monoboride (CoB) nanocrystals embedded in an amorphous layer of cobalt(II) and partially oxidized boron as a model platform to study morphological, chemical, and structural evolutions of the boride and the superficial layer exposed to argon, dihydrogen (H 2 ), and a mixture of H 2 and carbon dioxide (CO 2 ) through a multiscale in situ approach: environmental transmission electron microscopy, synchrotron-based near-ambient-pressure X-ray photoelectron spectroscopy, and near-edge X-ray absorption spectroscopy. Although the material is stable under argon, H 2 triggers at 400 °C decomposition of CoB, leading to cobalt(0) nanoparticles. We then show that H 2 activates CoB for the catalysis of CO 2 methanation. A similar decomposition process is also observed on NiB nanocrystals under oxidizing conditions at 300 °C. Our work highlights the instability under reactive atmospheres of nanocrystalline cobalt and nickel borides obtained from molten salt synthesis. Therefore, we question the general stability of metal borides with distinct compositions under such conditions. These results shed light on the actual species in metal boride catalysis and provide the framework for future applications of metal borides in their stability domains.

  11. Fluconazole affects the alkali-metal-cation homeostasis and susceptibility to cationic toxic compounds of Candida glabrata.

    PubMed

    Elicharova, Hana; Sychrova, Hana

    2014-08-01

    Candida glabrata is a salt-tolerant and fluconazole (FLC)-resistant yeast species. Here, we analyse the contribution of plasma-membrane alkali-metal-cation exporters, a cation/proton antiporter and a cation ATPase to cation homeostasis and the maintenance of membrane potential (ΔΨ). Using a series of single and double mutants lacking CNH1 and/or ENA1 genes we show that the inability to export potassium and toxic alkali-metal cations leads to a slight hyperpolarization of the plasma membrane of C. glabrata cells; this hyperpolarization drives more cations into the cells and affects cation homeostasis. Surprisingly, a much higher hyperpolarization of C. glabrata plasma membrane was produced by incubating cells with subinhibitory concentrations of FLC. FLC treatment resulted in a substantially increased sensitivity of cells to various cationic drugs and toxic cations that are driven into the cell by negative-inside plasma-membrane potential. The effect of the combination of FLC plus cationic drug treatment was enhanced by the malfunction of alkali-metal-cation transporters that contribute to the regulation of membrane potential and cation homeostasis. In summary, we show that the combination of subinhibitory concentrations of FLC and cationic drugs strongly affects the growth of C. glabrata cells. © 2014 The Authors.

  12. Positive electrode current collector for liquid metal cells

    DOEpatents

    Shimotake, Hiroshi; Bartholme, Louis G.

    1984-01-01

    A current collector for the positive electrode of an electrochemical cell with a positive electrode including a sulfide. The cell also has a negative electrode and a molten salt electrolyte including halides of a metal selected from the alkali metals and the alkaline earth metals in contact with both the positive and negative electrodes. The current collector has a base metal of copper, silver, gold, aluminum or alloys thereof with a coating thereon of iron, nickel, chromium or alloys thereof. The current collector when subjected to cell voltage forms a sulfur-containing compound on the surface thereby substantially protecting the current collector from further attack by sulfur ions during cell operation. Both electroless and electrolytic processes may be used to deposit coatings.

  13. Alkali Metal Doping for Improved CH3NH3PbI3 Perovskite Solar Cells.

    PubMed

    Zhao, Wangen; Yao, Zhun; Yu, Fengyang; Yang, Dong; Liu, Shengzhong Frank

    2018-02-01

    Organic-inorganic hybrid halide perovskites are proven to be a promising semiconductor material as the absorber layer of solar cells. However, the perovskite films always suffer from nonuniform coverage or high trap state density due to the polycrystalline characteristics, which degrade the photoelectric properties of thin films. Herein, the alkali metal ions which are stable against oxidation and reduction are used in the perovskite precursor solution to induce the process of crystallization and nucleation, then affect the properties of the perovskite film. It is found that the addition of the alkali metal ions clearly improves the quality of perovskite film: enlarges the grain sizes, reduces the defect state density, passivates the grain boundaries, increases the built-in potential ( V bi ), resulting to the enhancement in the power conversion efficiency of perovskite thin film solar cell.

  14. Behavior and structure of metal vapor arc plasma between molten electrodes

    NASA Astrophysics Data System (ADS)

    Zanner, F. J.; Williamson, R. L.; Hareland, W. A.; Bertram, L. A.

    A metal vapor arc is utilized in the industrially important vacuum arc remelting (VAR) process to produce materials by melting and resolidification which have improved structure and chemical homogeneity. Homogeneity is dependent on achieving quasi-steady conditions in the plasma because of its thermal and MHD coupling with the molten pool atop the ingot. Optimal operating conditions of low pressure (approx. = 0.01 torr) and short electrode gap (less than 15 mm) produce a diffuse arc and cathode spot behavior similar to that observed for the vacuum breaker arc. Under these conditions the arc provides a quasi-steady heat source that is considered to be the bench mark arc of the VAR process. Previous work has shown that deviation from the bench mark arc behavior can occur under production conditions, and is caused by electrode irregularities and liberation of gases such as CO from the molten pool. This study is an effort to characterize these behavioral deviations and discover operational conditions which stabilize the bench mark arc.

  15. Raman and nuclear magnetic resonance investigation of alkali metal vapor interaction with alkene-based anti-relaxation coating

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tretiak, O. Yu., E-mail: otretiak@genphys.ru; Balabas, M. V.; Blanchard, J. W.

    2016-03-07

    The use of anti-relaxation coatings in alkali vapor cells yields substantial performance improvements compared to a bare glass surface by reducing the probability of spin relaxation in wall collisions by several orders of magnitude. Some of the most effective anti-relaxation coating materials are alpha-olefins, which (as in the case of more traditional paraffin coatings) must undergo a curing period after cell manufacturing in order to achieve the desired behavior. Until now, however, it has been unclear what physicochemical processes occur during cell curing, and how they may affect relevant cell properties. We present the results of nondestructive Raman-spectroscopy and magnetic-resonancemore » investigations of the influence of alkali metal vapor (Cs or K) on an alpha-olefin, 1-nonadecene coating the inner surface of a glass cell. It was found that during the curing process, the alkali metal catalyzes migration of the carbon-carbon double bond, yielding a mixture of cis- and trans-2-nonadecene.« less

  16. Creep resistant, metal-coated LiFeO.sub.2 anodes for molten carbonated fuel cells

    DOEpatents

    Khandkar, Ashok C.

    1994-01-01

    A porous, creep-resistant, metal-coated, LiFeO.sub.2 ceramic electrode for fuel cells is disclosed. The electrode is particularly useful for molten carbonate fuel cells (MCFC) although it may have utilities in solid oxide fuel cells (SOFC) as well.

  17. Effects of arginine on rabbit muscle creatine kinase and salt-induced molten globule-like state.

    PubMed

    Ou, Wen-bin; Wang, Ri-Sheng; Lu, Jie; Zhou, Hai-Meng

    2003-11-03

    The arginine (Arg)-induced unfolding and the salt-induced folding of creatine kinase (CK) have been studied by measuring enzyme activity, fluorescence emission spectra, native polyacrylamide gel electrophoresis and size exclusion chromatography (SEC). The results showed that Arg caused inactivation and unfolding of CK, but there was no aggregation during CK denaturation. The kinetics of CK unfolding followed a one-phase process. At higher concentrations of Arg (>160 mM), the CK dimers were fully dissociated, the alkali characteristic of Arg mainly led to the dissociation of dimers, but not denaturation effect of Arg's guanidine groups on CK. The inactivation of CK occurred before noticeable conformational changes of the whole molecules. KCl induced monomeric and dimeric molten globule-like states of CK denatured by Arg. These results suggest that as a protein denaturant, the effect of Arg on CK differed from that of guanidine and alkali, its denaturation for protein contains the double effects, which acts not only as guanidine hydrochloride but also as alkali. The active sites of CK have more flexibility than the whole enzyme conformation. Monomeric and dimeric molten globule-like states of CK were formed by the salt inducing in 160 and 500 mM Arg H(2)O solutions, respectively. The molten globule-like states indicate that monomeric and dimeric intermediates exist during CK folding. Furthermore, these results also proved the orderly folding model of CK.

  18. Structural and dynamical trends in alkali-metal silanides characterized by neutron-scattering methods

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tang, Wan Si; Dimitrievska, Mirjana; Chotard, Jean -Noel

    Structural, vibrational, and dynamical properties of the mono- and mixed-alkali silanides (MSiH 3, where M = K, Rb, Cs, K 0.5Rb 0.5, K 0.5Cs 0.5, and Rb 0.5Cs 0.5) were investigated by various neutron experiments, including neutron powder diffraction (NPD), neutron vibrational spectroscopy (NVS), neutron-scattering fixed-window scans (FWSs), and quasielastic neutron scattering (QENS) measurements. Structural characterization showed that the mixed compounds exhibit disordered (α) and ordered (β) phases for temperatures above and below about 200–250 K, respectively, in agreement with their monoalkali correspondents. Vibrational and dynamical properties are strongly influenced by the cation environment; in particular, there is a redmore » shift in the band energies of the librational and bending modes with increasing lattice size as a result of changes in the bond lengths and force constants. Additionally, slightly broader spectral features are observed in the case of the mixed compounds, indicating the presence of structural disorder caused by the random distribution of the alkali-metal cations within the lattice. FWS measurements upon heating showed that there is a large increase in reorientational mobility as the systems go through the order–disorder (β–α) phase transition, and measurements upon cooling of the α-phase revealed the known strong hysteresis for reversion back to the β-phase. Interestingly, at a given temperature, among the different alkali silanide compounds, the relative reorientational mobilities of the SiH 3 – anions in the α- and β-phases tended to decrease and increase, respectively, with increasing alkali-metal mass. Lastly, this dynamical result might provide some insights concerning the enthalpy–entropy compensation effect previously observed for these potentially promising hydrogen storage materials.« less

  19. Structural and dynamical trends in alkali-metal silanides characterized by neutron-scattering methods

    DOE PAGES

    Tang, Wan Si; Dimitrievska, Mirjana; Chotard, Jean -Noel; ...

    2016-09-02

    Structural, vibrational, and dynamical properties of the mono- and mixed-alkali silanides (MSiH 3, where M = K, Rb, Cs, K 0.5Rb 0.5, K 0.5Cs 0.5, and Rb 0.5Cs 0.5) were investigated by various neutron experiments, including neutron powder diffraction (NPD), neutron vibrational spectroscopy (NVS), neutron-scattering fixed-window scans (FWSs), and quasielastic neutron scattering (QENS) measurements. Structural characterization showed that the mixed compounds exhibit disordered (α) and ordered (β) phases for temperatures above and below about 200–250 K, respectively, in agreement with their monoalkali correspondents. Vibrational and dynamical properties are strongly influenced by the cation environment; in particular, there is a redmore » shift in the band energies of the librational and bending modes with increasing lattice size as a result of changes in the bond lengths and force constants. Additionally, slightly broader spectral features are observed in the case of the mixed compounds, indicating the presence of structural disorder caused by the random distribution of the alkali-metal cations within the lattice. FWS measurements upon heating showed that there is a large increase in reorientational mobility as the systems go through the order–disorder (β–α) phase transition, and measurements upon cooling of the α-phase revealed the known strong hysteresis for reversion back to the β-phase. Interestingly, at a given temperature, among the different alkali silanide compounds, the relative reorientational mobilities of the SiH 3 – anions in the α- and β-phases tended to decrease and increase, respectively, with increasing alkali-metal mass. Lastly, this dynamical result might provide some insights concerning the enthalpy–entropy compensation effect previously observed for these potentially promising hydrogen storage materials.« less

  20. Degassing of molten alloys with the assistance of ultrasonic vibration

    DOEpatents

    Han, Qingyou; Xu, Hanbing; Meek, Thomas T.

    2010-03-23

    An apparatus and method are disclosed in which ultrasonic vibration is used to assist the degassing of molten metals or metal alloys thereby reducing gas content in the molten metals or alloys. High-intensity ultrasonic vibration is applied to a radiator that creates cavitation bubbles, induces acoustic streaming in the melt, and breaks up purge gas (e.g., argon or nitrogen) which is intentionally introduced in a small amount into the melt in order to collect the cavitation bubbles and to make the cavitation bubbles survive in the melt. The molten metal or alloy in one version of the invention is an aluminum alloy. The ultrasonic vibrations create cavitation bubbles and break up the large purge gas bubbles into small bubbles and disperse the bubbles in the molten metal or alloy more uniformly, resulting in a fast and clean degassing.

  1. Electronically conductive ceramics for high temperature oxidizing environments

    DOEpatents

    Kucera, Gene H.; Smith, James L.; Sim, James W.

    1986-01-01

    A high temperature, ceramic composition having electronic conductivity as measured by resistivity below about 500 ohm-cm, chemical stability particularly with respect to cathode conditions in a molten carbonate fuel cell, and composed of an alkali metal, transition metal oxide containing a dopant metal in the crystalline structure to replace a portion of the alkali metal or transition metal.

  2. Creep resistant, metal-coated LiFeO[sub 2] anodes for molten carbonated fuel cells

    DOEpatents

    Khandkar, A.C.

    1994-08-23

    A porous, creep-resistant, metal-coated, LiFeO[sub 2] ceramic electrode for fuel cells is disclosed. The electrode is particularly useful for molten carbonate fuel cells (MCFC) although it may have utilities in solid oxide fuel cells (SOFC) as well. 11 figs.

  3. Method and apparatus for removal of gaseous, liquid and particulate contaminants from molten metals

    DOEpatents

    Hobson, D.O.; Alexeff, I.; Sikka, V.K.

    1987-08-10

    Method and apparatus for removal of nonelectrically-conducting gaseous, liquid, and particulate contaminants from molten metal compositions by applying a force thereto. The force (commonly referred to as the Lorentz Force) exerted by simultaneous application of an electric field and a magnetic field on a molten conductor causes an increase, in the same direction as the force, in the apparent specific gravity thereof, but does not affect the nonconducting materials. This difference in apparent densities cause the nonconducting materials to ''float'' in the opposite direction from the Lorentz Force at a rapid rate. Means are further provided for removal of the contaminants and prevention of stirring due to rotational forces generated by the applied fields. 6 figs.

  4. Method and apparatus for removal of gaseous, liquid and particulate contaminants from molten metals

    DOEpatents

    Hobson, David O.; Alexeff, Igor; Sikka, Vinod K.

    1988-01-01

    Method and apparatus for removal of nonelectrically-conducting gaseous, liquid, and particulate contaminants from molten metal compositions by applying a force thereto. The force (commonly referred to as the Lorentz Force) exerted by simultaneous application of an electric field and a magnetic field on a molten conductor causes an increase, in the same direction as the force, in the apparent specific gravity thereof, but does not affect the nonconducting materials. This difference in apparent densities cause the nonconducting materials to "float" in the opposite direction from the Lorentz Force at a rapid rate. Means are further provided for removal of the contaminants and prevention of stirring due to rotational forces generated by the applied fields.

  5. Time-dependent calculations of molten pool formation and thermal plasma with metal vapour in gas tungsten arc welding

    NASA Astrophysics Data System (ADS)

    Tanaka, M.; Yamamoto, K.; Tashiro, S.; Nakata, K.; Yamamoto, E.; Yamazaki, K.; Suzuki, K.; Murphy, A. B.; Lowke, J. J.

    2010-11-01

    A gas tungsten arc (GTA) was modelled taking into account the contamination of the plasma by metal vapour from the molten anode. The whole region of GTA atmosphere including the tungsten cathode, the arc plasma and the anode was treated using a unified numerical model. A viscosity approximation was used to express the diffusion coefficient in terms of viscosity of the shielding gas and metal vapour. The transient two-dimensional distributions of temperature, velocity of plasma flow and iron vapour concentration were predicted, together with the molten pool as a function of time for a 150 A arc current at atmospheric pressure, both for helium and argon gases. It was shown that the thermal plasma in the GTA was influenced by iron vapour from the molten pool surface and that the concentration of iron vapour in the plasma was dependent on the temperature of the molten pool. GTA on high sulfur stainless steel was calculated to discuss the differences between a low sulfur and a high sulfur stainless steel anode. Helium was selected as the shielding gas because a helium GTA produces more metal vapour than an argon GTA. In the GTA on a high sulfur stainless steel anode, iron vapour and current path were constricted. Radiative emission density in the GTA on high sulfur stainless steel was also concentrated in the centre area of the arc plasma together with the iron vapour although the temperature distributions were almost the same as that in the case of a low sulfur stainless steel anode.

  6. Polarization and mass transfer during the electrolysis of molten salts with liquid metallic electrodes

    NASA Astrophysics Data System (ADS)

    Mikhalev, Yu. G.

    2014-08-01

    Calculations are used to show that the fraction of the overvoltage of the stage of discharge-ionization can be significant in the total overvoltage during the polarization of liquid metallic electrodes in molten chlorides depleted of electrochemically active particles (depending on the type of the dissipative structures that appear near the electrode/electrolyte interface). This finding is taken into account to obtain criterion equations to describe the mass-transfer rate as a function of the physicochemical properties of the electrolyte and the metal electrode.

  7. Electron core ionization in compressed alkali metal cesium

    NASA Astrophysics Data System (ADS)

    Degtyareva, V. F.

    2018-01-01

    Elements of groups I and II in the periodic table have valence electrons of s-type and are usually considered as simple metals. Crystal structures of these elements at ambient pressure are close-packed and high-symmetry of bcc and fcc-types, defined by electrostatic (Madelung) energy. Diverse structures were found under high pressure with decrease of the coordination number, packing fraction and symmetry. Formation of complex structures can be understood within the model of Fermi sphere-Brillouin zone interactions and supported by Hume-Rothery arguments. With the volume decrease there is a gain of band structure energy accompanied by a formation of many-faced Brillouin zone polyhedra. Under compression to less than a half of the initial volume the interatomic distances become close to or smaller than the ionic radius which should lead to the electron core ionization. At strong compression it is necessary to assume that for alkali metals the valence electron band overlaps with the upper core electrons, which increases the valence electron count under compression.

  8. Heat transfer of molten metal layers in severe accidents

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wong, Seung Kai; Walton, A.; Yang, Zhilin

    1997-12-01

    In some scenarios of severe accidents of light water reactors, a layer of molten metal from internal structural components of the pressure vessel is predicted to occur on top of a ceramic core debris in the lower head. The layer transfers the heat generated in the ceramic pool to the side wall of the vessel, causing the latter to melt. This problem has been investigated by Theofanous et al. for the advanced light water reactor AP600 in the context of the accident management strategy of ex-vessel cooling, and the conclusion was drawn that the melting does not seriously compromise themore » integrity of the pressure vessel.« less

  9. Electronically conductive ceramics for high temperature oxidizing environments

    DOEpatents

    Kucera, G.H.; Smith, J.L.; Sim, J.W.

    1983-11-10

    This invention pertains to a high temperature, ceramic composition having electronic conductivity as measured by resistivity below about 500 ohm-cm, chemical stability particularly with respect to cathode conditions in a molten carbonate fuel cell, and composed of an alkali metal, transition metal oxide containing a dopant metal in the crystalline structure to replace a portion of the alkali metal or transition metal.

  10. Gas Atomization of Molten Metal: Part I. Numerical Modeling Conception

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Leon, Genaro Perez-de; Lamberti, Vincent E.; Seals, Roland D.

    This numerical analysis study entails creating and assessing a model that is capable of simulating molten metal droplets and the production of metal powder during the Gas Atomization (GA) method. The essential goal of this research aims to gather more information on simulating the process of creating metal powder. The model structure and perspective was built through the application of governing equations and aspects that utilized factors such as gas dynamics, droplet dynamics, energy balance, heat transfer, fluid mechanics and thermodynamics that were proposed from previous studies. The model is very simple and can be broken down into having amore » set of inputs to produce outputs. The inputs are the processing parameters such as the initial temperature of the metal alloy, the gas pressure and the size of the droplets. Additional inputs include the selection of the metal alloy and the atomization gas and factoring in their properties. The outputs can be designated by the velocity and thermal profiles of the droplet and gas. These profiles illustrate the speed of both as well as the rate of temperature change or cooling rate of the droplets. Here, the main focus is the temperature change and finding the right parameters to ensure that the metal powder is efficiently produced. Once the model was conceptualized and finalized, it was employed to verify the results of other previous studies.« less

  11. Gas Atomization of Molten Metal: Part I. Numerical Modeling Conception

    DOE PAGES

    Leon, Genaro Perez-de; Lamberti, Vincent E.; Seals, Roland D.; ...

    2016-02-01

    This numerical analysis study entails creating and assessing a model that is capable of simulating molten metal droplets and the production of metal powder during the Gas Atomization (GA) method. The essential goal of this research aims to gather more information on simulating the process of creating metal powder. The model structure and perspective was built through the application of governing equations and aspects that utilized factors such as gas dynamics, droplet dynamics, energy balance, heat transfer, fluid mechanics and thermodynamics that were proposed from previous studies. The model is very simple and can be broken down into having amore » set of inputs to produce outputs. The inputs are the processing parameters such as the initial temperature of the metal alloy, the gas pressure and the size of the droplets. Additional inputs include the selection of the metal alloy and the atomization gas and factoring in their properties. The outputs can be designated by the velocity and thermal profiles of the droplet and gas. These profiles illustrate the speed of both as well as the rate of temperature change or cooling rate of the droplets. Here, the main focus is the temperature change and finding the right parameters to ensure that the metal powder is efficiently produced. Once the model was conceptualized and finalized, it was employed to verify the results of other previous studies.« less

  12. Alkali metal/halide thermal energy storage systems performance evaluation

    NASA Technical Reports Server (NTRS)

    Phillips, W. M.; Stearns, J. W.

    1986-01-01

    A pseudoheat-pipe heat transfer mechanism has been demonstrated effective in terms of both total heat removal efficiency and rate, on the one hand, and system isothermal characteristics, on the other, for solar thermal energy storage systems of the kind being contemplated for spacecraft. The selection of appropriate salt and alkali metal substances for the system renders it applicable to a wide temperature range. The rapid heat transfer rate obtainable makes possible the placing of the thermal energy storage system around the solar receiver canister, and the immersing of heat transfer fluid tubes in the phase change salt to obtain an isothermal heat source.

  13. Electrolytic method for the production of lithium using a lithium-amalgam electrode

    DOEpatents

    Cooper, John F.; Krikorian, Oscar H.; Homsy, Robert V.

    1979-01-01

    A method for recovering lithium from its molten amalgam by electrolysis of the amalgam in an electrolytic cell containing as a molten electrolyte a fused-salt consisting essentially of a mixture of two or more alkali metal halides, preferably alkali metal halides selected from lithium iodide, lithium chloride, potassium iodide and potassium chloride. A particularly suitable molten electrolyte is a fused-salt consisting essentially of a mixture of at least three components obtained by modifying an eutectic mixture of LiI-KI by the addition of a minor amount of one or more alkali metal halides. The lithium-amalgam fused-salt cell may be used in an electrolytic system for recovering lithium from an aqueous solution of a lithium compound, wherein electrolysis of the aqueous solution in an aqueous cell in the presence of a mercury cathode produces a lithium amalgam. The present method is particularly useful for the regeneration of lithium from the aqueous reaction products of a lithium-water-air battery.

  14. Analysis of the Alkali Metal Diatomic Spectra; Using molecular beams and ultracold molecules

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Tae

    2014-12-01

    This ebook illustrates the complementarity of molecular beam (MB) spectra and ultracold molecule (UM) spectra in unraveling the complex electronic spectra of diatomic alkali metal molecules, using KRb as a prime example. Researchers interested in molecular spectroscopy, whether physicist, chemist, or engineer, may find this ebook helpful and may be able to apply similar ideas to their molecules of interest.

  15. Molten salts and energy related materials.

    PubMed

    Fray, Derek

    2016-08-15

    Molten salts have been known for centuries and have been used for the extraction of aluminium for over one hundred years and as high temperature fluxes in metal processing. This and other molten salt routes have gradually become more energy efficient and less polluting, but there have been few major breakthroughs. This paper will explore some recent innovations that could lead to substantial reductions in the energy consumed in metal production and in carbon dioxide production. Another way that molten salts can contribute to an energy efficient world is by creating better high temperature fuel cells and novel high temperature batteries, or by acting as the medium that can create novel materials that can find applications in high energy batteries and other energy saving devices, such as capacitors. Carbonate melts can be used to absorb carbon dioxide, which can be converted into C, CO and carbon nanoparticles. Molten salts can also be used to create black silicon that can absorb more sunlight over a wider range of wavelengths. Overall, there are many opportunities to explore for molten salts to play in an efficient, low carbon world.

  16. Post-harvest processing methods for reduction of silica and alkali metals in wheat straw.

    PubMed

    Thompson, David N; Shaw, Peter G; Lacey, Jeffrey A

    2003-01-01

    Silica and alkali metals in wheat straw limit its use for bioenergy and gasification. Slag deposits occur via the eutectic melting of SiO2 with K2O, trapping chlorides at surfaces and causing corrosion. A minimum melting point of 950 degrees C is desirable, corresponding to an SiO2:K2O weight ratio of about 3:1. Mild chemical treatments were used to reduce Si, K, and Cl, while varying temperature, concentration, % solids, and time. Dilute acid was more effective at removing K and Cl, while dilute alkali was more effective for Si. Reduction of minerals in this manner may prove economical for increasing utilization of the straw for combustion or gasification.

  17. Structure factor of liquid alkali metals using a classical-plasma reference system

    NASA Astrophysics Data System (ADS)

    Pastore, G.; Tosi, M. P.

    1984-06-01

    This paper presents calculations of the liquid structure factor of the alkali metals near freezing, starting from the classical plasma of bare ions as reference liquid. The indirect ion-ion interaction arising from electronic screening is treated by an optimized random phase approximation (ORPA), imposing physical requirements as in the original ORPA scheme developed by Weeks, Chandler and Andersen for liquids with strongly repulsive core potentials. A comparison of the results with computer simulation data for a model of liquid rubidium shows that the present approach overcomes the well-known difficulties met in applying to these metals the standard ORPA based on a reference liquid of neutral hard spheres. The optimization scheme is also shown to be equivalent to a reduction of the range of the indirect interaction in momentum space, as proposed empirically in an earlier work. Comparison with experiment for the other alkalis shows that a good overall representation of the data can be obtained for sodium, potassium and cesium, but not for lithium, when one uses a very simple form of the electron-ion potential adjusted to the liquid compressibility. The small-angle scattering region is finally examined more carefully in the light of recent data of Waseda, with a view to possible refinements of the pseudopotential model.

  18. Ternary Amides Containing Transition Metals for Hydrogen Storage: A Case Study with Alkali Metal Amidozincates.

    PubMed

    Cao, Hujun; Richter, Theresia M M; Pistidda, Claudio; Chaudhary, Anna-Lisa; Santoru, Antonio; Gizer, Gökhan; Niewa, Rainer; Chen, Ping; Klassen, Thomas; Dornheim, Martin

    2015-11-01

    The alkali metal amidozincates Li4 [Zn(NH2)4](NH2)2 and K2[Zn(NH2)4] were, to the best of our knowledge, studied for the first time as hydrogen storage media. Compared with the LiNH2-2 LiH system, both Li4 [Zn(NH2)4](NH2)2-12 LiH and K2[Zn(NH2)4]-8 LiH systems showed improved rehydrogenation performance, especially K2[Zn(NH2)4]-8 LiH, which can be fully hydrogenated within 30 s at approximately 230 °C. The absorption properties are stable upon cycling. This work shows that ternary amides containing transition metals have great potential as hydrogen storage materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Low-temperature fabrication of alkali metal-organic charge transfer complexes on cotton textile for optoelectronics and gas sensing.

    PubMed

    Ramanathan, Rajesh; Walia, Sumeet; Kandjani, Ahmad Esmaielzadeh; Balendran, Sivacarendran; Mohammadtaheri, Mahsa; Bhargava, Suresh Kumar; Kalantar-zadeh, Kourosh; Bansal, Vipul

    2015-02-03

    A generalized low-temperature approach for fabricating high aspect ratio nanorod arrays of alkali metal-TCNQ (7,7,8,8-tetracyanoquinodimethane) charge transfer complexes at 140 °C is demonstrated. This facile approach overcomes the current limitation associated with fabrication of alkali metal-TCNQ complexes that are based on physical vapor deposition processes and typically require an excess of 800 °C. The compatibility of soft substrates with the proposed low-temperature route allows direct fabrication of NaTCNQ and LiTCNQ nanoarrays on individual cotton threads interwoven within the 3D matrix of textiles. The applicability of these textile-supported TCNQ-based organic charge transfer complexes toward optoelectronics and gas sensing applications is established.

  20. Heavier alkali-metal monosulfides (KS, RbS, CsS, and FrS) and their cations.

    PubMed

    Lee, Edmond P F; Wright, Timothy G

    2005-10-08

    The heavier alkali-metal monosulfides (KS, RbS, CsS, and FrS) have been studied by high-level ab initio calculations. The RCCSD(T) method has been employed, combined with large flexible valence basis sets. All-electron basis sets are used for potassium and sulfur, with effective core potentials being used for the other metals, describing the core electrons. Potential-energy curves are calculated for the lowest two neutral and cationic states: all neutral monosulfide species have a (2)Pi ground state, in contrast with the alkali-metal monoxide species, which undergo a change in the electronic ground state from (2)Pi to (2)Sigma(+) as the group is descended. In the cases of KS, RbS, and CsS, spin-orbit curves are also calculated. We also calculate potential-energy curves for the lowest (3)Sigma(-) and (3)Pi states of the cations. From the potential-energy curves, spectroscopic constants are derived, and for KS the spectroscopic results are compared to experimental spectroscopic values. Ionization energies, dissociation energies, and heats of formation are also calculated; for KS, we explore the effects of relativity and basis set extrapolation on these values.

  1. Surface Tension of Liquid Alkali, Alkaline, and Main Group Metals: Theoretical Treatment and Relationship Investigations

    NASA Astrophysics Data System (ADS)

    Aqra, Fathi; Ayyad, Ahmed

    2011-09-01

    An improved theoretical method for calculating the surface tension of liquid metals is proposed. A recently derived equation that allows an accurate estimate of surface tension to be made for the large number of elements, based on statistical thermodynamics, is used for a means of calculating reliable values for the surface tension of pure liquid alkali, alkaline earth, and main group metals at the melting point, In order to increase the validity of the model, the surface tension of liquid lithium was calculated in the temperature range 454 K to 1300 K (181 °C to 1027 °C), where the calculated surface tension values follow a straight line behavior given by γ = 441 - 0.15 (T-Tm) (mJ m-2). The calculated surface excess entropy of liquid Li (- dγ/ dT) was found to be 0.15 mJ m-2 K-1, which agrees well with the reported experimental value (0.147 mJ/m2 K). Moreover, the relations of the calculated surface tension of alkali metals to atomic radius, heat of fusion, and specific heat capacity are described. The results are in excellent agreement with the existing experimental data.

  2. Challenges and Prospect of Non-aqueous Non-alkali (NANA) Metal-Air Batteries.

    PubMed

    Gelman, Danny; Shvartsev, Boris; Ein-Eli, Yair

    2016-12-01

    Non-aqueous non-alkali (NANA) metal-air battery technologies promise to provide electrochemical energy storage with the highest specific energy density. Metal-air battery technology is particularly advantageous being implemented in long-range electric vehicles. Up to now, almost all the efforts in the field are focused on Li-air cells, but other NANA metal-air battery technologies emerge. The major concern, which the research community should be dealing with, is the limited and rather poor rechargeability of these systems. The challenges we are covering in this review are related to the initial limited discharge capacities and cell performances. By comprehensively reviewing the studies conducted so far, we show that the implementation of advanced materials is a promising approach to increase metal-air performance and, particularly, metal surface activation as a prime achievement leading to respectful discharge currents. In this review, we address the most critical areas that need careful research attention in order to achieve progress in the understanding of the physical and electrochemical processes in non-aqueous electrolytes applied in beyond lithium and zinc air generation of metal-air battery systems.

  3. Origin of low sodium capacity in graphite and generally weak substrate binding of Na and Mg among alkali and alkaline earth metals.

    PubMed

    Liu, Yuanyue; Merinov, Boris V; Goddard, William A

    2016-04-05

    It is well known that graphite has a low capacity for Na but a high capacity for other alkali metals. The growing interest in alternative cation batteries beyond Li makes it particularly important to elucidate the origin of this behavior, which is not well understood. In examining this question, we find a quite general phenomenon: among the alkali and alkaline earth metals, Na and Mg generally have the weakest chemical binding to a given substrate, compared with the other elements in the same column of the periodic table. We demonstrate this with quantum mechanics calculations for a wide range of substrate materials (not limited to C) covering a variety of structures and chemical compositions. The phenomenon arises from the competition between trends in the ionization energy and the ion-substrate coupling, down the columns of the periodic table. Consequently, the cathodic voltage for Na and Mg is expected to be lower than those for other metals in the same column. This generality provides a basis for analyzing the binding of alkali and alkaline earth metal atoms over a broad range of systems.

  4. Theoretical study of mixed MLaX(4) (M = Na, K, Cs; X = F, Cl, Br, I) rare earth/alkali metal halide complexes.

    PubMed

    Groen, Cornelis Petrus; Oskam, Ad; Kovács, Attila

    2003-02-10

    The structure, bonding, and vibrational properties of the mixed MLaX(4) (M = Na, K, Cs; X = F, Cl, Br, I) rare earth/alkali metal halide complexes have been studied using the MP2 method in conjunction with polarized triple-zeta valence basis sets and quasi-relativistic effective core potentials for the heavy atoms. From the three characteristic structures, possessing 1- (C(3)(v)), 2- (C(2)(v)), or 3-fold coordination (C(3)(v)) between the alkali metal and the bridging halide atoms, the bi- and tridentate forms are stable isomers with close dissociation energies. In general, for the complexes existing of lighter alkali metals and halogens, the bidentate structure corresponds to the global minimum of the potential energy surface, while the heavier analogues favor the tridentate structure. At experimentally relevant temperatures (T > 800 K), however, the isomerization entropy leads to a domination of the bidentate structures over the tridentate forms for all complexes. An important effect of the size of the alkali metal is manifested in the larger stabilities of the K and Cs complexes. The natural atomic charges are in agreement with strong electrostatic interactions in the title complexes. The marginal covalent contributions show a slight increasing trend in the heavier analogues. The calculated vibrational data indicate that infrared spectroscopy may be an effective tool for experimental investigation and characterization of MLaX(4) molecules.

  5. Bond-length distributions for ions bonded to oxygen: alkali and alkaline-earth metals.

    PubMed

    Gagné, Olivier Charles; Hawthorne, Frank Christopher

    2016-08-01

    Bond-length distributions have been examined for 55 configurations of alkali-metal ions and 29 configurations of alkaline-earth-metal ions bonded to oxygen, for 4859 coordination polyhedra and 38 594 bond distances (alkali metals), and for 3038 coordination polyhedra and 24 487 bond distances (alkaline-earth metals). Bond lengths generally show a positively skewed Gaussian distribution that originates from the variation in Born repulsion and Coulomb attraction as a function of interatomic distance. The skewness and kurtosis of these distributions generally decrease with increasing coordination number of the central cation, a result of decreasing Born repulsion with increasing coordination number. We confirm the following minimum coordination numbers: ([3])Li(+), ([3])Na(+), ([4])K(+), ([4])Rb(+), ([6])Cs(+), ([3])Be(2+), ([4])Mg(2+), ([6])Ca(2+), ([6])Sr(2+) and ([6])Ba(2+), but note that some reported examples are the result of extensive dynamic and/or positional short-range disorder and are not ordered arrangements. Some distributions of bond lengths are distinctly multi-modal. This is commonly due to the occurrence of large numbers of structure refinements of a particular structure type in which a particular cation is always present, leading to an over-representation of a specific range of bond lengths. Outliers in the distributions of mean bond lengths are often associated with anomalous values of atomic displacement of the constituent cations and/or anions. For a sample of ([6])Na(+), the ratio Ueq(Na)/Ueq(bonded anions) is partially correlated with 〈([6])Na(+)-O(2-)〉 (R(2) = 0.57), suggesting that the mean bond length is correlated with vibrational/displacement characteristics of the constituent ions for a fixed coordination number. Mean bond lengths also show a weak correlation with bond-length distortion from the mean value in general, although some coordination numbers show the widest variation in mean bond length for zero distortion, e.g. Li(+) in

  6. Alkali-Metal-Ion-Functionalized Graphene Oxide as a Superior Anode Material for Sodium-Ion Batteries.

    PubMed

    Wan, Fang; Li, Yu-Han; Liu, Dai-Huo; Guo, Jin-Zhi; Sun, Hai-Zhu; Zhang, Jing-Ping; Wu, Xing-Long

    2016-06-06

    Although graphene oxide (GO) has large interlayer spacing, it is still inappropriate to use it as an anode for sodium-ion batteries (SIBs) because of the existence of H-bonding between the layers and ultralow electrical conductivity which impedes the Na(+) and e(-) transformation. To solve these issues, chemical, thermal, and electrochemical procedures are traditionally employed to reduce GO nanosheets. However, these strategies are still unscalable, consume high amounts of energy, and are expensive for practical application. Here, for the first time, we describe the superior Na storage of unreduced GO by a simple and scalable alkali-metal-ion (Li(+) , Na(+) , K(+) )-functionalized process. The various alkali metals ions, connecting with the oxygen on GO, have played different effects on morphology, porosity, degree of disorder, and electrical conductivity, which are crucial for Na-storage capabilities. Electrochemical tests demonstrated that sodium-ion-functionalized GO (GNa) has shown outstanding Na-storage performance in terms of excellent rate capability and long-term cycle life (110 mAh g(-1) after 600 cycles at 1 A g(-1) ) owing to its high BET area, appropriate mesopore, high degree of disorder, and improved electrical conductivity. Theoretical calculations were performed using the generalized gradient approximation (GGA) to further study the Na-storage capabilities of functionalized GO. These calculations have indicated that the Na-O bond has the lowest binding energy, which is beneficial to insertion/extraction of the sodium ion, hence the GNa has shown the best Na-storage properties among all comparatives functionalized by other alkali metal ions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Electrochemical cell

    DOEpatents

    Redey, Laszlo I.; Myles, Kevin M.; Vissers, Donald R.; Prakash, Jai

    1996-01-01

    An electrochemical cell with a positive electrode having an electrochemically active layer of at least one transition metal chloride. A negative electrode of an alkali metal and a compatible electrolyte including an alkali metal salt molten at cell operating temperature is included in the cell. The electrolyte is present at least partially as a corrugated .beta." alumina tube surrounding the negative electrode interior to the positive electrode. The ratio of the volume of liquid electrolyte to the volume of the positive electrode is in the range of from about 0.1 to about 3. A plurality of stacked electrochemical cells is disclosed each having a positive electrode, a negative electrode of an alkali metal molten at cell operating temperature, and a compatible electrolyte. The electrolyte is at least partially present as a corrugated .beta." alumina sheet separating the negative electrode and interior to the positive electrodes. The alkali metal is retained in a porous electrically conductive ceramic, and seals for sealing the junctures of the electrolyte and the adjacent electrodes at the peripheries thereof.

  8. Electrochemical cell

    DOEpatents

    Redey, L.I.; Myles, K.M.; Vissers, D.R.; Prakash, J.

    1996-07-02

    An electrochemical cell is described with a positive electrode having an electrochemically active layer of at least one transition metal chloride. A negative electrode of an alkali metal and a compatible electrolyte including an alkali metal salt molten at cell operating temperature is included in the cell. The electrolyte is present at least partially as a corrugated {beta}{double_prime} alumina tube surrounding the negative electrode interior to the positive electrode. The ratio of the volume of liquid electrolyte to the volume of the positive electrode is in the range of from about 0.1 to about 3. A plurality of stacked electrochemical cells is disclosed each having a positive electrode, a negative electrode of an alkali metal molten at cell operating temperature, and a compatible electrolyte. The electrolyte is at least partially present as a corrugated {beta}{double_prime} alumina sheet separating the negative electrode and interior to the positive electrodes. The alkali metal is retained in a porous electrically conductive ceramic, and seals for sealing the junctures of the electrolyte and the adjacent electrodes at the peripheries thereof. 8 figs.

  9. Novel waste printed circuit board recycling process with molten salt.

    PubMed

    Riedewald, Frank; Sousa-Gallagher, Maria

    2015-01-01

    The objective of the method was to prove the concept of a novel waste PCBs recycling process which uses inert, stable molten salts as the direct heat transfer fluid and, simultaneously, uses this molten salt to separate the metal products in either liquid (solder, zinc, tin, lead, etc.) or solid (copper, gold, steel, palladium, etc.) form at the operating temperatures of 450-470 °C. The PCB recovery reactor is essentially a U-shaped reactor with the molten salt providing a continuous fluid, allowing molten salt access from different depths for metal recovery. A laboratory scale batch reactor was constructed using 316L as suitable construction material. For safety reasons, the inert, stable LiCl-KCl molten salts were used as direct heat transfer fluid. Recovered materials were washed with hot water to remove residual salt before metal recovery assessment. The impact of this work was to show metal separation using molten salts in one single unit, by using this novel reactor methodology. •The reactor is a U-shaped reactor filled with a continuous liquid with a sloped bottom representing a novel reactor concept.•This method uses large PCB pieces instead of shredded PCBs as the reactor volume is 2.2 L.•The treated PCBs can be removed via leg B while the process is on-going.

  10. Novel waste printed circuit board recycling process with molten salt

    PubMed Central

    Riedewald, Frank; Sousa-Gallagher, Maria

    2015-01-01

    The objective of the method was to prove the concept of a novel waste PCBs recycling process which uses inert, stable molten salts as the direct heat transfer fluid and, simultaneously, uses this molten salt to separate the metal products in either liquid (solder, zinc, tin, lead, etc.) or solid (copper, gold, steel, palladium, etc.) form at the operating temperatures of 450–470 °C. The PCB recovery reactor is essentially a U-shaped reactor with the molten salt providing a continuous fluid, allowing molten salt access from different depths for metal recovery. A laboratory scale batch reactor was constructed using 316L as suitable construction material. For safety reasons, the inert, stable LiCl–KCl molten salts were used as direct heat transfer fluid. Recovered materials were washed with hot water to remove residual salt before metal recovery assessment. The impact of this work was to show metal separation using molten salts in one single unit, by using this novel reactor methodology. • The reactor is a U-shaped reactor filled with a continuous liquid with a sloped bottom representing a novel reactor concept. • This method uses large PCB pieces instead of shredded PCBs as the reactor volume is 2.2 L. • The treated PCBs can be removed via leg B while the process is on-going. PMID:26150977

  11. Crucible cast from beryllium oxide and refractory cement is impervious to flux and molten metal

    NASA Technical Reports Server (NTRS)

    Jastrzebski, Z. D.

    1966-01-01

    Crucible from a mixture of a beryllium oxide aggregate and hydraulic refractory cement, and coated with an impervious refractory oxide will not deteriorate in the presence of fused salt- molten metal mixtures such as uranium- magnesium-zinc-halide salt systems. Vessels cast by this process are used in the flux reduction of oxides of thorium and uranium.

  12. Spin relaxation in ultracold collisions of molecular radicals with alkali-metal atoms

    NASA Astrophysics Data System (ADS)

    Tscherbul, Timur; Klos, Jacek; Zukowski, Piotr

    2016-05-01

    We present accurate quantum scattering calculations of spin relaxation in ultracold collisions of alkali-metal atoms and polar 2 Σ molecules CaH, SrF, and SrOH. The calculations employ state-of-the-art ab initio interaction potentials and a rigorous quantum theory of atom-molecule collisions in a magnetic field based on the total angular momentum representation. We will further discuss the relevance of the results to atom-molecule sympathetic cooling experiments in a magnetic trap.

  13. Alkali Metal CO2 Sorbents and the Resulting Metal Carbonates: Potential for Process Intensification of Sorption-Enhanced Steam Reforming.

    PubMed

    Memon, Muhammad Zaki; Zhao, Xiao; Sikarwar, Vineet Singh; Vuppaladadiyam, Arun K; Milne, Steven J; Brown, Andy P; Li, Jinhui; Zhao, Ming

    2017-01-03

    Sorption-enhanced steam reforming (SESR) is an energy and cost efficient approach to produce hydrogen with high purity. SESR makes it economically feasible to use a wide range of feedstocks for hydrogen production such as methane, ethanol, and biomass. Selection of catalysts and sorbents plays a vital role in SESR. This article reviews the recent research aimed at process intensification by the integration of catalysis and chemisorption functions into a single material. Alkali metal ceramic powders, including Li 2 ZrO 3 , Li 4 SiO 4 and Na 2 ZrO 3 display characteristics suitable for capturing CO 2 at low concentrations (<15% CO 2 ) and high temperatures (>500 °C), and thus are applicable to precombustion technologies such as SESR, as well as postcombustion capture of CO 2 from flue gases. This paper reviews the progress made in improving the operational performance of alkali metal ceramics under conditions that simulate power plant and SESR operation, by adopting new methods of sorbent synthesis and doping with additional elements. The paper also discusses the role of carbonates formed after in situ CO 2 chemisorption during a steam reforming process in respect of catalysts for tar cracking.

  14. Ultralow-power local laser control of the dimer density in alkali-metal vapors through photodesorption

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jha, Pankaj K.; Scully, Marlan O.; Princeton University, Princeton, New Jersey 08544

    2012-08-27

    Ultralow-power diode-laser radiation is employed to induce photodesorption of cesium from a partially transparent thin-film cesium adsorbate on a solid surface. Using resonant Raman spectroscopy, we demonstrate that this photodesorption process enables an accurate local optical control of the density of dimer molecules in alkali-metal vapors.

  15. Pseudopotential theoretical study of the alkali metals under arbitrary pressure: Density, bulk modulus, and shear moduli

    NASA Astrophysics Data System (ADS)

    Rasky, Daniel J.; Milstein, Frederick

    1986-02-01

    Milstein and Hill previously derived formulas for computing the bulk and shear moduli, κ, μ, and μ', at arbitrary pressures, for cubic crystals in which interatomic interaction energies are modeled by pairwise functions, and they carried out the moduli computations using the complete family of Morse functions. The present study extends their work to a pseudopotential description of atomic binding. Specifically: (1) General formulas are derived for determining these moduli under hydrostatic loading within the framework of a pseudopotential model. (2) A two-parameter pseudopotential model is used to describe atomic binding of the alkali metals, and the two parameters are determined from experimental data (the model employs the Heine-Abarenkov potential with the Taylor dielectric function). (3) For each alkali metal (Li, Na, K, Rb, and Cs), the model is used to compute the pressure-versus-volume behavior and, at zero pressure, the binding energy, the density, and the elastic moduli and their pressure derivatives; the theoretical behavior is found to be in excellent agreement with experiment. (4) Calculations are made of κ, μ, and μ' of the bcc alkali metals over wide ranges of hydrostatic compression and expansion. (5) The pseudopotential results are compared with those of arbitrary-central-force models (wherein κ-(2/3)μ=μ'+2P) and with the specific Morse-function results. The pressures, bulk moduli, and zero-pressure shear moduli (as determined for the Morse and pseudopotential models) are in excellent agreement, but important differences appear in the shear moduli under high compressions. The computations in the present paper are for the bcc metals; a subsequent paper will extend this work to include both the bcc and fcc structures, at compressions and expansions where elastic stability or lattice cohesion is, in practice, lost.

  16. Promoter Effects of Alkali Metal Cations on the Electrochemical Reduction of Carbon Dioxide

    DOE PAGES

    Resasco, Joaquin; Chen, Leanne D.; Clark, Ezra; ...

    2017-07-24

    The electrochemical reduction of CO 2 is known to be influenced by the identity of the alkali metal cation in the electrolyte; however, a satisfactory explanation for this phenomenon has not been developed. Here we present the results of experimental and theoretical studies aimed at elucidating the effects of electrolyte cation size on the intrinsic activity and selectivity of metal catalysts for the reduction of CO 2. Experiments were conducted under conditions where the influence of electrolyte polarization is minimal in order to show that cation size affects the intrinsic rates of formation of certain reaction products, most notably formore » HCOO –, C 2H 4, and C 2H 5OH over Cu(100)- and Cu(111)-oriented thin films, and for CO and HCOO– over polycrystalline Ag and Sn. Interpretation of the findings for CO 2 reduction was informed by studies of the reduction of glyoxal and CO, key intermediates along the reaction pathway to final products. Density functional theory calculations show that the alkali metal cations influence the distribution of products formed as a consequence of electrostatic interactions between solvated cations present at the outer Helmholtz plane and adsorbed species having large dipole moments. As a result, the observed trends in activity with cation size are attributed to an increase in the concentration of cations at the outer Helmholtz plane with increasing cation size.« less

  17. Promoter Effects of Alkali Metal Cations on the Electrochemical Reduction of Carbon Dioxide

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Resasco, Joaquin; Chen, Leanne D.; Clark, Ezra

    The electrochemical reduction of CO 2 is known to be influenced by the identity of the alkali metal cation in the electrolyte; however, a satisfactory explanation for this phenomenon has not been developed. Here we present the results of experimental and theoretical studies aimed at elucidating the effects of electrolyte cation size on the intrinsic activity and selectivity of metal catalysts for the reduction of CO 2. Experiments were conducted under conditions where the influence of electrolyte polarization is minimal in order to show that cation size affects the intrinsic rates of formation of certain reaction products, most notably formore » HCOO –, C 2H 4, and C 2H 5OH over Cu(100)- and Cu(111)-oriented thin films, and for CO and HCOO– over polycrystalline Ag and Sn. Interpretation of the findings for CO 2 reduction was informed by studies of the reduction of glyoxal and CO, key intermediates along the reaction pathway to final products. Density functional theory calculations show that the alkali metal cations influence the distribution of products formed as a consequence of electrostatic interactions between solvated cations present at the outer Helmholtz plane and adsorbed species having large dipole moments. As a result, the observed trends in activity with cation size are attributed to an increase in the concentration of cations at the outer Helmholtz plane with increasing cation size.« less

  18. Silicon halide-alkali metal flames as a source of solar grade silicon

    NASA Technical Reports Server (NTRS)

    Olsen, D. B.; Miller, W. J.

    1979-01-01

    The feasibility of using alkali metal-silicon halide diffusion flames to produce solar-grade silicon in large quantities and at low cost is demonstrated. Prior work shows that these flames are stable and that relatively high purity silicon can be produced using Na + SiCl4 flames. Silicon of similar purity is obtained from Na + SiF4 flames although yields are lower and product separation and collection are less thermochemically favored. Continuous separation of silicon from the byproduct alkali salt was demonstrated in a heated graphite reactor. The process was scaled up to reduce heat losses and to produce larger samples of silicon. Reagent delivery systems, scaled by a factor of 25, were built and operated at a production rate of 0.5 kg Si/h. Very rapid reactor heating rates are observed with wall temperatures reaching greater than 2000 K. Heat release parameters were measured using a cooled stainless steel reactor tube. A new reactor was designed.

  19. From Oxygen Generation to Metals Production: In Situ Resource Utilization by Molten Oxide Electrolysis

    NASA Technical Reports Server (NTRS)

    Khetpal, Deepak; Ducret, Andrew C.; Sadoway, Donald R.

    2003-01-01

    For the exploration of other bodies in the solar system, electrochemical processing is arguably the most versatile technology for conversion of local resources into usable commodities: by electrolysis one can, in principle, produce (1) breathable oxygen, (2) silicon for the fabrication of solar cells, (3) various reactive metals for use as electrodes in advanced storage batteries, and (4) structural metals such as steel and aluminum. Even so, to date there has been no sustained effort to develop such processes, in part due to the inadequacy of the database. The objective here is to identify chemistries capable of sustaining molten oxide electrolysis in the cited applications and to examine the behavior of laboratory-scale cells designed to generate oxygen and to produce metal. The basic research includes the study of the underlying high-temperature physical chemistry of oxide melts representative of lunar regolith and of Martian soil. To move beyond empirical approaches to process development, the thermodynamic and transport properties of oxide melts are being studied to help set the limits of composition and temperature for the processing trials conducted in laboratory-scale electrolysis cells. The goal of this investigation is to deliver a working prototype cell that can use lunar regolith and Martian soil to produce breathable oxygen along with metal by-product. Additionally, the process can be generalized to permit adaptation to accommodate different feedstock chemistries, such as those that will be encountered on other bodies in the solar system. The expected results of this research include: (1) the identification of appropriate electrolyte chemistries; (2) the selection of candidate anode and cathode materials compatible with electrolytes named above; and (3) performance data from a laboratory-scale cell producing oxygen and metal. On the strength of these results it should be possible to assess the technical viability of molten oxide electrolysis for in

  20. Method of treating alkali metal sulfide and carbonate mixtures

    DOEpatents

    Kohl, Arthur L.; Rennick, Robert D.; Savinsky, Martin W.

    1978-01-01

    A method of removing and preferably recovering sulfur values from an alkali metal sulfide and carbonate mixture comprising the steps of (1) introducing the mixture in an aqueous medium into a first carbonation zone and reacting the mixture with a gas containing a major amount of CO.sub.2 and a minor amount of H.sub.2 S; (2) introducing the resultant product from step 1 into a stripping zone maintained at subatmospheric pressure, and contacting this product with steam to produce a gaseous mixture, comprising H.sub.2 S and water vapor, and a liquor of reduced sulfide content; (3) introducing the liquor of reduced sulfide content into a second carbonation zone, and reacting the liquor with substantially pure gaseous CO.sub.2 in an amount sufficient to precipitate bicarbonate crystals and produce an offgas containing CO.sub.2 and H.sub.2 S for use in step 1; (4) recovering the bicarbonate crystals from step 3, and thermally decomposing the crystals to produce an alkaline metal carbonate product and a substantially pure CO.sub.2 offgas for use in step 3.

  1. Experimental (FT-IR, FT-Raman, 1H, 13C NMR) and theoretical study of alkali metal 2-aminobenzoates

    NASA Astrophysics Data System (ADS)

    Samsonowicz, M.; Świsłocka, R.; Regulska, E.; Lewandowski, W.

    2008-09-01

    The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the 2-aminobenzoic acid was studied by the methods of molecular spectroscopy. The vibrational (FT-IR, FT-Raman) and NMR ( 1H and 13C) spectra for 2-aminobenzoic acid and its alkali metal salts were recorded. The assignment of vibrational spectra was done on the basis of literature data, theoretical calculations and our previous experience. Characteristic shifts of bands and changes in intensities of bands along the metal series were observed. The changes of chemical shifts of protons ( 1H NMR) and carbons ( 13C NMR) in the series of studied alkali metal 2-aminobenzoates were observed too. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G ∗∗ basis set. Geometric aromaticity indices, dipole moments and energies were also calculated. The theoretical wavenumbers and intensities of IR and Raman spectra were obtained. The calculated parameters were compared to experimental characteristic of studied compounds.

  2. Method for the regeneration of spent molten zinc chloride

    DOEpatents

    Zielke, Clyde W.; Rosenhoover, William A.

    1981-01-01

    In a process for regenerating spent molten zinc chloride which has been used in the hydrocracking of coal or ash-containing polynuclear aromatic hydrocarbonaceous materials derived therefrom and which contains zinc chloride, zinc oxide, zinc oxide complexes and ash-containing carbonaceous residue, by incinerating the spent molten zinc chloride to vaporize the zinc chloride for subsequent condensation to produce a purified molten zinc chloride: an improvement comprising the use of clay in the incineration zone to suppress the vaporization of metals other than zinc. Optionally water is used in conjunction with the clay to further suppress the vaporization of metals other than zinc.

  3. Implementation of Hydrodynamic Simulation Code in Shock Experiment Design for Alkali Metals

    NASA Astrophysics Data System (ADS)

    Coleman, A. L.; Briggs, R.; Gorman, M. G.; Ali, S.; Lazicki, A.; Swift, D. C.; Stubley, P. G.; McBride, E. E.; Collins, G.; Wark, J. S.; McMahon, M. I.

    2017-10-01

    Shock compression techniques enable the investigation of extreme P-T states. In order to probe off-Hugoniot regions of P-T space, target makeup and laser pulse parameters must be carefully designed. HYADES is a hydrodynamic simulation code which has been successfully utilised to simulate shock compression events and refine the experimental parameters required in order to explore new P-T states in alkali metals. Here we describe simulations and experiments on potassium, along with the techniques required to access off-Hugoniot states.

  4. Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

    DOEpatents

    Maroni, V.A.; von Winbush, S.

    1987-05-01

    A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500/degree/C, electrolysis at a voltage not more negative that about /minus/1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

  5. Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

    DOEpatents

    Maroni, Victor A.; von Winbush, Samuel

    1988-01-01

    A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500.degree. C., electrolysis at a voltage not more negative than about -1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

  6. Wick-and-pool electrodes for electrochemical cell

    DOEpatents

    Roche, Michael F.; Faist, Suzan M.; Eberhart, James G.; Ross, Laurids E.

    1977-01-01

    An electrode system includes a reservoir of liquid-metal reactant, and a wick extending from a submersed location within the reservoir into the molten electrolyte of an electrochemical cell structure. The wick is flooded with the liquid metal and thereby serves as one electrode within the cell. This electrode system has application in high-temperature batteries employing molten alkali metals or their alloys as active material within an electrode submersed within a molten salt electrolyte. It also can be used in electrochemical cells where the purification, separation or electrowinning of liquid metals is accomplished.

  7. Wick-and-pool electrodes for electrochemical cell

    DOEpatents

    Roche, Michael F.; Faist, Suzan M.; Eberhart, James G.; Ross, Laurids E.

    1980-01-01

    An electrode system includes a reservoir of liquid-metal reactant, and a wick extending from a submersed location within the reservoir into the molten electrolyte of an electrochemical cell structure. The wick is flooded with the liquid metal and thereby serves as one electrode within the cell. This electrode system has application in high-temperature batteries employing molten alkali metals or their alloys as active material within an electrode submersed within a molten salt electrolyte. It also can be used in electrochemical cells where the purification, separation or electrowinning of liquid metals is accomplished.

  8. An Assessment of Molten Metal Detachment Hazards During Electron Beam Welding in the Space Shuttle Bay at LEO for the International Space Welding Experiment

    NASA Technical Reports Server (NTRS)

    Fragomeni, James M.

    1996-01-01

    In 1997, the United States [NASA] and the Paton Electric Welding Institute are scheduled to cooperate in a flight demonstration on the U.S. Space Shuttle to demonstrate the feasibility of welding in space for a possible repair option for the International Space Station Alpha. This endeavor, known as the International Space Welding Experiment (ISWE), will involve astronauts performing various welding exercises such as brazing, cutting, welding, and coating using an electron beam space welding system that was developed by the E.O. Paton Electric Welding Institute (PWI), Kiev Ukraine. This electron beam welding system known as the "Universal Weld System" consists of hand tools capable of brazing, cutting, autogeneous welding, and coating using an 8 kV (8000 volts) electron beam. The electron beam hand tools have also been developed by the Paton Welding Institute with greater capabilities than the original hand tool, including filler wire feeding, to be used with the Universal Weld System on the U.S. Space Shuttle Bay as part of ISWE. The hand tool(s) known as the Ukrainian Universal Hand [Electron Beam Welding] Tool (UHT) will be utilized for the ISWE Space Shuttle flight welding exercises to perform welding on various metal alloy samples. A total of 61 metal alloy samples, which include 304 stainless steel, Ti-6AI-4V, 2219 aluminum, and 5456 aluminum alloys, have been provided by NASA for the ISWE electron beam welding exercises using the UHT. These samples were chosen to replicate both the U.S. and Russian module materials. The ISWE requires extravehicular activity (EVA) of two astronauts to perform the space shuttle electron beam welding operations of the 61 alloy samples. This study was undertaken to determine if a hazard could exist with ISWE during the electron beam welding exercises in the Space Shuttle Bay using the Ukrainian Universal Weld System with the UHT. The safety issue has been raised with regard to molten metal detachments as a result of several

  9. Electrodeposition of Dense Chromium Coatings from Molten Salt Electrolytes

    DTIC Science & Technology

    1991-04-01

    AD-A235 978 . JUN 03 391 ELECTRODEPOSITION OF DENSE CHROMIUM COATINGS FROM MOLTEN SALT ELECTROLYTES Final Technical Report J t ]Vgca or by ~ 4 OTC... molten salts , pulsed currents, electrodeposition. 2. The results, on the electrodeposition of dense chromium coatings from molten salt electrolytes... salts dissolved in molten salts using the cell Cl2/C/!Cr 2 + in LiCI-KCI//Cr metal The chromium ions are introduced by anodizing a piece of chromium and

  10. Rechargeable Al/Cl2 battery with molten AlCl4/-/ electrolyte.

    NASA Technical Reports Server (NTRS)

    Holleck, G. L.; Giner, J.; Burrows, B.

    1972-01-01

    A molten salt system based on Al- and Cl2 carbon electrodes, with an AlCl3 alkali chloride eutectic as electrolyte, offers promise as a rechargeable, high energy density battery which can operate at a relatively low temperature. Electrode kinetic studies showed that the electrode reactions at the Al anode were rapid and that the observed passivation phenomena were due to the formation at the electrode surface of a solid salt layer resulting from concentration changes on anodic or cathodic current flow. It was established that carbon electrodes were intrinsically active for chlorine reduction in AlCl3-alkali chloride melts. By means of a rotating vitreous carbon disk electrode, the kinetic parameters were determined.

  11. Performance and properties of anodes reinforced with metal oxide nanoparticles for molten carbonate fuel cells

    NASA Astrophysics Data System (ADS)

    Accardo, Grazia; Frattini, Domenico; Yoon, Sung Pil; Ham, Hyung Chul; Nam, Suk Woo

    2017-12-01

    Development of electrode materials for molten carbonate fuel cells is a fundamental issue as a balance between mechanical and electrochemical properties is required due to the particular operating environments of these cells. As concern the anode, a viable strategy is to use nano-reinforced particles during electrodes' fabrication. Candidate nanomaterials comprise, but are not limited to, ZrO2, CeO2, TiO2, Ti, Mg, Al, etc. This work deals with the characterization and test of two different types of hard oxide nanoparticles as reinforce for NiAl-based anodes in molten carbonate fuel cells. Nano ceria and nano zirconia are compared each other and single cell test performances are presented. Compared to literature, the use of hard metal oxide nanoparticles allows good performance and promising perspectives with respect to the use a third alloying metal. However, nano zirconia performed slightly better than nano ceria as polarization and power curves are higher even if nano ceria has the highest mechanical properties. This means that the choice of nanoparticles to obtain improved anodes performance and properties is not trivial and a trade-off between relevant properties plays a key role.

  12. Absorption Spectroscopy of Rubidium in an Alkali Metal Dispenser Cell and Bleached Wave Analysis

    DTIC Science & Technology

    2015-03-26

    Department of Engineering Physics Graduate School of Engineering and Management Air Force Institute of Technology Air University Air Education and...at atmospheric temperatures and pressures, so none of the safety measures needed with pure solid alkali metal would be required. AMDs can also be...Institute of Technology Graduate School of Engineering and Management (AFIT/ENP) 2950 Hobson Way WPAFB OH 45433-7765 8. PERFORMING ORGANIZATION

  13. Presence of Li Clusters in Molten LiCl-Li

    PubMed Central

    Merwin, Augustus; Phillips, William C.; Williamson, Mark A.; Willit, James L.; Motsegood, Perry N.; Chidambaram, Dev

    2016-01-01

    Molten mixtures of lithium chloride and metallic lithium are of significant interest in various metal oxide reduction processes. These solutions have been reported to exhibit seemingly anomalous physical characteristics that lack a comprehensive explanation. In the current work, the physical chemistry of molten solutions of lithium chloride and metallic lithium, with and without lithium oxide, was investigated using in situ Raman spectroscopy. The Raman spectra obtained from these solutions were in agreement with the previously reported spectrum of the lithium cluster, Li8. This observation is indicative of a nanofluid type colloidal suspension of Li8 in a molten salt matrix. It is suggested that the formation and suspension of lithium clusters in lithium chloride is the cause of various phenomena exhibited by these solutions that were previously unexplainable. PMID:27145895

  14. Electrochemical Impedance Spectroscopic Study on Eu 2+ and Sr 2+ Using Liquid Metal Cathodes in Molten Chlorides

    NASA Astrophysics Data System (ADS)

    Matsumiya, Masahiko; Takagi, Ryuzo

    2000-08-01

    For the pyrochemical reprocessing of spent metallic nuclear fuels in molten salt baths it is important to investigate the behavior of the electrochemically negative elements Eu and Sr, which are significant fission products. Voltammetric and chronopotentiometric studies have shown that the reduction of Eu 2+ and Sr 2+ on liquid Pb cathodes in molten chloride baths at 1073 K follows the alloy formation reaction: Eu 2+ + 2e- + 3Pb → EuPb 3 and Sr 2+ + 2e- + 3Pb → SrPb 3 . In the present work these alloy formation reactions were studiedby electrochemical impedance spectroscopy. Analysis of the spectra showed that the electronic exchange of Eu 2+ /Eu and Sr 2+ /Sr is quasi-re-versible. Moreover, the experimental results allowed the determination of the kinetic parameters of EU 2+ /EU and Sr 2+ /Sr, the diffusion coefficients of these species in molten chloride baths, and also the diffusion layer thickness.

  15. Ionic conductivity of β-cyclodextrin-polyethylene-oxide/alkali-metal-salt complex.

    PubMed

    Yang, Ling-Yun; Fu, Xiao-Bin; Chen, Tai-Qiang; Pan, Li-Kun; Ji, Peng; Yao, Ye-Feng; Chen, Qun

    2015-04-20

    Highly conductive, crystalline, polymer electrolytes, β-cyclodextrin (β-CD)-polyethylene oxide (PEO)/LiAsF6 and β-CD-PEO/NaAsF6 , were prepared through supramolecular self-assembly of PEO, β-CD, and LiAsF6 /NaAsF6 . The assembled β-CDs form nanochannels in which the PEO/X(+) (X=Li, Na) complexes are confined. The nanochannels provide a pathway for directional motion of the alkali metal ions and, at the same time, separate the cations and the anions by size exclusion. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Thermal behavior of heat-pipe-assisted alkali-metal thermoelectric converters

    NASA Astrophysics Data System (ADS)

    Lee, Ji-Su; Lee, Wook-Hyun; Chi, Ri-Guang; Chung, Won-Sik; Lee, Kye-Bock; Rhi, Seok-Ho; Jeong, Seon-Yong; Park, Jong-Chan

    2017-11-01

    The alkali-metal thermal-to-electric converter (AMTEC) changes thermal energy directly into electrical energy using alkali metals, such as sodium and potassium, as the working fluid. The AMTEC system primarily consists of beta-alumina solid electrolyte (BASE) tubes, low and high-pressure chambers, an evaporator, and a condenser and work through continuous sodium circulation, similar to conventional heat pipes. When the sodium ions pass through the BASE tubes with ion conductivity, this ion transfer generates electricity. The efficiency of the AMTEC directly depends on the temperature difference between the top and bottom of the system. The optimum design of components of the AMTEC, including the condenser, evaporator, BASE tubes, and artery wick, can improve power output and efficiency. Here, a radiation shield was installed in the low-pressure chamber of the AMTEC and was investigated experimentally and numerically to determine an optimum design for preventing radiation heat loss through the condenser and the wall of AMTEC container. A computational fluid dynamics (CFD) simulation was carried out to decide the optimum size of the low-pressure chamber. The most suitable height and diameter of the chamber were 270 mm and 180 mm, respectively, with eight BASE tubes, which were 150 mm high, 25 mm in diameter, and 105 mm in concentric diameter. Increasing the temperature ratio ( T Cond /T B ) led to high power output. The minimum dimensionless value (0.4611) for temperature ( T Cond /T B ) appeared when the radiation shield was made of 500-mesh nickel. Simulation results for the best position and shape for the radiation shield, revealed that maximum power was generated when a stainless steel shield was installed in between the BASE tubes and condenser.

  17. Effects of Cations on Corrosion of Inconel 625 in Molten Chloride Salts

    NASA Astrophysics Data System (ADS)

    Zhu, Ming; Ma, Hongfang; Wang, Mingjing; Wang, Zhihua; Sharif, Adel

    2016-04-01

    Hot corrosion of Inconel 625 in sodium chloride, potassium chloride, magnesium chloride, calcium chloride and their mixtures with different compositions is conducted at 900°C to investigate the effects of cations in chloride salts on corrosion behavior of the alloy. XRD, SEM/EDS were used to analyze the compositions, phases, and morphologies of the corrosion products. The results showed that Inconel 625 suffers more severe corrosion in alkaline earth metal chloride molten salts than alkaline metal chloride molten salts. For corrosion in mixture salts, the corrosion rate increased with increasing alkaline earth metal chloride salt content in the mixture. Cations in the chloride molten salts mainly affect the thermal and chemical properties of the salts such as vapor pressure and hydroscopicities, which can affect the basicity of the molten salt. Corrosion of Inconel 625 in alkaline earth metal chloride salts is accelerated with increasing basicity.

  18. Gas Atomization of Molten Metal: Part II. Applications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Abu-Lebdeh, Taher M.; Leon, Genaro Perez-de; Hamoush, Sameer A.

    A numerical model was derived to obtain results for two alloys during the Gas Atomization (GA) method. The model equations and governing equations were implemented through the application of part I data. Aspects such as heat transfer, fluid mechanics, thermodynamics and law of motions were taken into account for the formulation of equations that take gas dynamics, droplet dynamics and energy balance or conservation into consideration. The inputs of the model include: Processing parameters such as the size of the droplets, characteristics of the metal alloy, initial temperature of the molten metal, properties and fractions of the atomization gas andmore » the gas pressure. The outputs include velocity and thermal profiles of the droplet and gas. Velocity profiles illustrate the velocity of both droplet and gas, while thermal profiles illustrate cooling rate and the rate of temperature change of the droplets. The alloys are gamma-Titanium Aluminide (γ-TiAl) and Al-3003-O. These alloys were selected due to the vast amount of applications both can have in several industries. Certain processing parameters were held constant, while others were altered. Furthermore, the main focus of this study was to gain insight into which optimal parameters should be utilized within the GA method for these alloys and to provide insight into the behavior of these alloys« less

  19. Gas Atomization of Molten Metal: Part II. Applications

    DOE PAGES

    Abu-Lebdeh, Taher M.; Leon, Genaro Perez-de; Hamoush, Sameer A.; ...

    2016-02-01

    A numerical model was derived to obtain results for two alloys during the Gas Atomization (GA) method. The model equations and governing equations were implemented through the application of part I data. Aspects such as heat transfer, fluid mechanics, thermodynamics and law of motions were taken into account for the formulation of equations that take gas dynamics, droplet dynamics and energy balance or conservation into consideration. The inputs of the model include: Processing parameters such as the size of the droplets, characteristics of the metal alloy, initial temperature of the molten metal, properties and fractions of the atomization gas andmore » the gas pressure. The outputs include velocity and thermal profiles of the droplet and gas. Velocity profiles illustrate the velocity of both droplet and gas, while thermal profiles illustrate cooling rate and the rate of temperature change of the droplets. The alloys are gamma-Titanium Aluminide (γ-TiAl) and Al-3003-O. These alloys were selected due to the vast amount of applications both can have in several industries. Certain processing parameters were held constant, while others were altered. Furthermore, the main focus of this study was to gain insight into which optimal parameters should be utilized within the GA method for these alloys and to provide insight into the behavior of these alloys« less

  20. Novel ternary molten salt electrolytes for intermediate-temperature sodium/nickel chloride batteries

    NASA Astrophysics Data System (ADS)

    Li, Guosheng; Lu, Xiaochuan; Coyle, Christopher A.; Kim, Jin Y.; Lemmon, John P.; Sprenkle, Vincent L.; Yang, Zhenguo

    2012-12-01

    The sodium-nickel chloride (ZEBRA) battery is operated at relatively high temperature (250-350 °C) to achieve adequate electrochemical performance. Reducing the operating temperature in the range of 150200 °C can not only lead to enhanced cycle life by suppressing temperature-related degradations, but also allow the use of lower cost materials for construction. To achieve adequate electrochemical performance at lower operating temperatures, reduction in ohmic losses is required, including the reduced ohmic resistance of β″-alumina solid electrolyte (BASE) and the incorporation of low melting point secondary electrolytes. In present work, planar-type Na/NiCl2 cells with a thin BASE (600 μm) and low melting point secondary electrolyte were evaluated at reduced temperatures. Molten salts used as secondary electrolytes were fabricated by the partial replacement of NaCl in the standard secondary electrolyte (NaAlCl4) with other lower melting point alkali metal salts such as NaBr, LiCl, and LiBr. Electrochemical characterization of these ternary molten salts demonstrated improved ionic conductivity and sufficient electrochemical window at reduced temperatures. Furthermore, Na/NiCl2 cells with 50 mol% NaBr-containing secondary electrolyte exhibited reduced polarizations at 175 °C compared to the cell with the standard NaAlCl4 catholyte. The cells also exhibited stable cycling performance even at 150 °C.

  1. Electrochemical generation of useful chemical species from lunar materials

    NASA Technical Reports Server (NTRS)

    Sammells, Anthony F.; Semkow, Krystyna W.

    1987-01-01

    A high temperature electrolytic cell which simultaneously generates oxygen at the anode and liquid alkali metals at the cathode is electrochemically characterized. The electrolytic technology being investigated utilizes the oxygen vacancy conducting solid electrolyte, yttria stabilized zirconia, which effectively separates the oxygen evolving (at La0.89Sr0.10MnO3) and alkali metal (Li, Na) reducing (from a molten salt at either Pt or FeSi2) half cell reactions. In the finally engineered cell liquid alkali metal would be continuously removed from the cathode compartment and used as an effective reductant for the direct thermochemical refining of lunar ores to their metallic state with simultaneous oxidation of the alkali metal to its oxide. The alkali metal oxide would then be reintroduced into the electrolytic cell to complete the overall system cycle.

  2. Electrochemical generation of useful chemical species from lunar materials

    NASA Astrophysics Data System (ADS)

    Sammells, Anthony F.; Semkow, Krystyna W.

    1987-09-01

    A high temperature electrolytic cell which simultaneously generates oxygen at the anode and liquid alkali metals at the cathode is electrochemically characterized. The electrolytic technology being investigated utilizes the oxygen vacancy conducting solid electrolyte, yttria stabilized zirconia, which effectively separates the oxygen evolving (at La0.89Sr0.10MnO3) and alkali metal (Li, Na) reducing (from a molten salt at either Pt or FeSi2) half cell reactions. In the finally engineered cell liquid alkali metal would be continuously removed from the cathode compartment and used as an effective reductant for the direct thermochemical refining of lunar ores to their metallic state with simultaneous oxidation of the alkali metal to its oxide. The alkali metal oxide would then be reintroduced into the electrolytic cell to complete the overall system cycle.

  3. Chemical effects of alkali atoms on critical temperature in superconducting alkali-doped fullerides

    NASA Astrophysics Data System (ADS)

    Hetfleisch, F.; Gunnarsson, O.; Srama, R.; Han, J. E.; Stepper, M.; Roeser, H.-P.; Bohr, A.; Lopez, J. S.; Mashmool, M.; Roth, S.

    2018-03-01

    Alkali metal doped fullerides (A3C60) are superconductors with critical temperatures, Tc, extending up to 38 K. Tc is known to depend strongly on the lattice parameter a, which can be adjusted by physical or chemical pressure. In the latter case an alkali atom is replaced by a different sized one, which changes a. We have collected an extensive data base of experimental data for Tc from very early up to recent measurements. We disentangle alkali atom chemical effects on Tc, beyond the well-known consequences of changing a. It is found that Tc, for a fixed a, is typically increased as smaller alkali atoms are replaced by larger ones, except for very large a. Possible reasons for these results are discussed. Although smaller in size than the lattice parameter contribution, the chemical effect is not negligible and should be considered in future physical model developments.

  4. Alkali Metal Ion Complexes with Phosphates, Nucleotides, Amino Acids, and Related Ligands of Biological Relevance. Their Properties in Solution.

    PubMed

    Crea, Francesco; De Stefano, Concetta; Foti, Claudia; Lando, Gabriele; Milea, Demetrio; Sammartano, Silvio

    2016-01-01

    Alkali metal ions play very important roles in all biological systems, some of them are essential for life. Their concentration depends on several physiological factors and is very variable. For example, sodium concentrations in human fluids vary from quite low (e.g., 8.2 mmol dm(-3) in mature maternal milk) to high values (0.14 mol dm(-3) in blood plasma). While many data on the concentration of Na(+) and K(+) in various fluids are available, the information on other alkali metal cations is scarce. Since many vital functions depend on the network of interactions occurring in various biofluids, this chapter reviews their complex formation with phosphates, nucleotides, amino acids, and related ligands of biological relevance. Literature data on this topic are quite rare if compared to other cations. Generally, the stability of alkali metal ion complexes of organic and inorganic ligands is rather low (usually log K < 2) and depends on the charge of the ligand, owing to the ionic nature of the interactions. At the same time, the size of the cation is an important factor that influences the stability: very often, but not always (e.g., for sulfate), it follows the trend Li(+) > Na(+) > K(+) > Rb(+) > Cs(+). For example, for citrate it is: log K ML = 0.88, 0.80, 0.48, 0.38, and 0.13 at 25 °C and infinite dilution. Some considerations are made on the main aspects related to the difficulties in the determination of weak complexes. The importance of the alkali metal ion complexes was also studied in the light of modelling natural fluids and in the use of these cations as probes for different processes. Some empirical relationships are proposed for the dependence of the stability constants of Na(+) complexes on the ligand charge, as well as for correlations among log K values of NaL, KL or LiL species (L = generic ligand).

  5. Alkali-Resistant Mechanism of a Hollandite DeNOx Catalyst.

    PubMed

    Hu, Pingping; Huang, Zhiwei; Gu, Xiao; Xu, Fei; Gao, Jiayi; Wang, Yue; Chen, Yaxin; Tang, Xingfu

    2015-06-02

    A thorough understanding of the deactivation mechanism by alkalis is of great importance for rationally designing improved alkali-resistant deNOx catalysts, but a traditional ion-exchange mechanism cannot often accurately describe the nature of the deactivation, thus hampering the development of superior catalysts. Here, we establish a new exchange-coordination mechanism on the basis of the exhaustive study on the strong alkali resistance of a hollandite manganese oxide (HMO) catalyst. A combination of isothermal adsorption measurements of ammonia with X-ray absorption near-edge structure spectra and X-ray photoelectron spectra reveals that alkali metal ions first react with protons from Brønsted acid sites of HMO via the ion exchange. Synchrotron X-ray diffraction patterns and extended X-ray absorption fine structure spectra coupled with theoretical calculations demonstrate that the exchanged alkali metal ions are subsequently stabilized at size-suitable cavities in the HMO pores via a coordination model with an energy savings. This exchange-coordination mechanism not only gives a wholly convincing explanation for the intrinsic nature of the deactivation of the reported catalysts by alkalis but also provides a strategy for rationally designing improved alkali-resistant deNOx catalysts in general.

  6. Effect of mold designs on molten metal behaviour in high-pressure die casting

    NASA Astrophysics Data System (ADS)

    Ibrahim, M. D.; Rahman, M. R. A.; Khan, A. A.; Mohamad, M. R.; Suffian, M. S. Z. M.; Yunos, Y. S.; Wong, L. K.; Mohtar, M. Z.

    2017-04-01

    This paper presents a research study conducted in a local automotive component manufacturer that produces aluminium alloy steering housing local and global markets. This study is to investigate the effect of design modification of mold in die casting as to improve the production rate. Design modification is carried out on the casting shot of the mold. Computer flow simulation was carried out to study the flow of molten metal in the mold with respect to the mold design modification. The design parameters of injection speed, die temperature and clamping force has been included in the study. The result of the simulation showed that modifications of casting shot give significant impact towards the molten flow behaviour in casting process. The capabilities and limitations of die casting process simulation to conduct defect analysis had been optimized. This research will enhance the efficiency of the mass production of the industry of die casting with the understanding of defect analysis, which lies on the modification of the mold design, a way early in its stages of production.

  7. Insight from first principles into the stability and magnetism of alkali-metal superoxide nanoclusters

    NASA Astrophysics Data System (ADS)

    Arcelus, Oier; Suaud, Nicolas; Katcho, Nebil A.; Carrasco, Javier

    2017-05-01

    Alkali-metal superoxides are gaining increasing interest as 2p magnetic materials for information and energy storage. Despite significant research efforts on bulk materials, gaps in our knowledge of the electronic and magnetic properties at the nanoscale still remain. Here, we focused on the role that structural details play in determining stability, electronic structure, and magnetic couplings of (MO2)n (M = Li, Na, and K, with n = 2-8) clusters. Using first-principles density functional theory based on the Perdew-Burke-Ernzerhof and Heyd-Scuseria-Ernzerhof functionals, we examined the effect of atomic structure on the relative stability of different polymorphs within each investigated cluster size. We found that small clusters prefer to form planar-ring structures, whereas non-planar geometries become more stable when increasing the cluster size. However, the crossover point depends on the nature of the alkali metal. Our analysis revealed that electrostatic interactions govern the highly ionic M-O2 bonding and ultimately control the relative stability between 2-D and 3-D geometries. In addition, we analyzed the weak magnetic couplings between superoxide molecules in (NaO2)4 clusters comparing model Hamiltonian methods based on Wannier function projections onto πg states with wave function-based multi-reference calculations.

  8. Chemical Reactions of Simulated Producer Gas with Molten Tin-Bismuth Alloy

    Treesearch

    Keith J. Bourne

    2012-01-01

    A pyrolysis and gasification system utilizing molten metal as an energy carrier has been proposed and the initial stages of its design have been completed. However, there are several fundamental questions that need to be answered before the design of this system can be completed. These questions include: How will the molten metal interact with the products of biomass...

  9. Alkali metal cation complexation by 1,3-alternate, mono-ionisable calix[4]arene-benzocrown-6 compounds

    DOE PAGES

    Surowiec, Malgorzata A.; Custelcean, Radu; Surowiec, Kazimierz; ...

    2014-04-23

    Alkali metal cation extraction behavior for two series of 1,3-alternate, mono-ionizable calix[4]arene-benzocrown-6 compounds is examined. In Series 1, the proton-ionizable group is a substituent on the benzo group of the polyether ring that directs it away from the crown ether cavity. In Series 2, the proton-ionizable group is attached to one para position in the calixarene framework, thus positioning it over the crown ether ring. Competitive solvent extraction of alkali metal cations from aqueous solutions into chloroform shows high Cs+ efficiency and selectivity. Single-species extraction pH profiles of Cs+ for Series 1 and 2 ligands with the same proton-ionizable groupmore » are very similar. Thus, association of Cs+ with the calixcrown ring is more important than the the proton-ionizable group’s position in relation to the crown ether cavity. Solid-state structures are presented for two unionized ligands from Series 2, as is a crystal containing two different ionized ligand–Cs+ complexes.« less

  10. Calculating the thermodynamic properties of aqueous solutions of alkali metal carboxylates

    NASA Astrophysics Data System (ADS)

    Rudakov, A. M.; Sergievskii, V. V.; Zhukova, T. V.

    2014-06-01

    A modified Robinson-Stokes equation with terms that consider the formation of ionic hydrates and associates is used to describe thermodynamic properties of aqueous solutions of electrolytes. The model is used to describe data on the osmotic coefficients of aqueous solutions of alkali metal carboxylates, and to calculate the mean ionic activity coefficients of salts and excess Gibbs energies. The key contributions from ionic hydration and association to the nonideality of solutions is determined by analyzing the contributions of various factors. Relations that connect the hydration numbers of electrolytes with the parameters of the Pitzer-Mayorga equation and a modified Hückel equation are developed.

  11. Ultrafast and Stable CO2 Capture Using Alkali Metal Salt-Promoted MgO-CaCO3 Sorbents.

    PubMed

    Cui, Hongjie; Zhang, Qiming; Hu, Yuanwu; Peng, Chong; Fang, Xiangchen; Cheng, Zhenmin; Galvita, Vladimir V; Zhou, Zhiming

    2018-06-20

    As a potential candidate for precombustion CO 2 capture at intermediate temperatures (200-400 °C), MgO-based sorbents usually suffer from low kinetics and poor cyclic stability. Herein, a general and facile approach is proposed for the fabrication of high-performance MgO-based sorbents via incorporation of CaCO 3 into MgO followed by deposition of a mixed alkali metal salt (AMS). The AMS-promoted MgO-CaCO 3 sorbents are capable of adsorbing CO 2 at an ultrafast rate, high capacity, and good stability. The CO 2 uptake of sorbent can reach as high as above 0.5 g CO 2 g sorbent -1 after only 5 min of sorption at 350 °C, accounting for vast majority of the total uptake. In addition, the sorbents are very stable even under severe but more realistic conditions (desorption in CO 2 at 500 °C), where the CO 2 uptake of the best sorbent is stabilized at 0.58 g CO 2 g sorbent -1 in 20 consecutive cycles. The excellent CO 2 capture performance of the sorbent is mainly due to the promoting effect of molten AMS, the rapid formation of CaMg(CO 3 ) 2 , and the plate-like structure of sorbent. The exceptional ultrafast rate and the good stability of the AMS-promoted MgO-CaCO 3 sorbents promise high potential for practical applications, such as precombustion CO 2 capture from integrated gasification combined cycle plants and sorption-enhanced water gas shift process.

  12. Method and apparatus for spraying molten materials

    DOEpatents

    Glovan, R.J.; Tierney, J.C.; McLean, L.L.; Johnson, L.L.; Nelson, G.L.; Lee, Y.M.

    1996-06-25

    A metal spray apparatus is provided with a supersonic nozzle. Molten metal is injected into a gas stream flowing through the nozzle under pressure. By varying the pressure of the injected metal, the droplet can be made in various selected sizes with each selected size having a high degree of size uniformity. A unique one piece graphite heater provides easily controlled uniformity of temperature in the nozzle and an attached tundish which holds the pressurized molten metal. A unique U-shaped gas heater provides extremely hot inlet gas temperatures to the nozzle. A particularly useful application of the spray apparatus is coating of threads of a fastener with a shape memory alloy. This permits a fastener to be easily inserted and removed but provides for a secure locking of the fastener in high temperature environments. 12 figs.

  13. Non-Adiabatic Atomic Transitions: Computational Cross Section Calculations of Alkali Metal-Noble Gas Collisions

    DTIC Science & Technology

    2011-09-01

    there a one time transfer of prob- ability between Coriolis coupled states. One possible way to answer this question would be to literally create and... time -dependent numerical algorithm was developed using FORTRAN 90 to predict S-Matrix elements for alkali metal - noble gas (MNg) collisions. The...committee and the physics department for their time and effort to see me through the completion of my doctorate degree. Charlton D. Lewis, II v Table of

  14. Castable Cement Can Prevent Molten-Salt Corrosion in CSP

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    2016-09-01

    NREL's study demonstrated that castable cements on metals are a protective barrier that can prevent permeation of molten salts toward metallic surfaces. The silica-based castable cement Aremco 645-N, when sprayed with boron nitride, can protect containment metallic alloys from attack by molten chlorides at high temperatures (650 degrees C) in short-term tests. Improved thermal energy storage technology could increase the performance of CSP and reduce costs, helping to reach the goal of the U.S. Department of Energy's SunShot Initiative to make solar cost-competitive with other non-renewable sources of electricity by 2020.

  15. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None

    Since 1987, Westinghouse Hanford Company has been a major contractor to the U.S. Department of Energy-Richland Operations Office and has served as co-operator of the 3718-F Alkali Metal Treatment and Storage Facility, the waste management unit addressed in this closure plan. The closure plan consists of a Part A Dangerous waste Permit Application and a RCRA Closure Plan. An explanation of the Part A Revision (Revision 1) submitted with this document is provided at the beginning of the Part A section. The closure plan consists of 9 chapters and 5 appendices. The chapters cover: introduction; facility description; process information; wastemore » characteristics; groundwater; closure strategy and performance standards; closure activities; postclosure; and references.« less

  16. Development of processes for the production of solar grade silicon from halides and alkali metals

    NASA Technical Reports Server (NTRS)

    Dickson, C. R.; Gould, R. K.

    1980-01-01

    High temperature reactions of silicon halides with alkali metals for the production of solar grade silicon in volume at low cost were studied. Experiments were performed to evaluate product separation and collection processes, measure heat release parameters for scaling purposes, determine the effects of reactants and/or products on materials of reactor construction, and make preliminary engineering and economic analyses of a scaled-up process.

  17. Preparation and Use of Alkali Metals (Li and Na) in Alumina and Silica Gel as Reagents in Organic Syntheses

    NASA Astrophysics Data System (ADS)

    Jalloh, Fatmata

    This work describes the development of alkali metals (Li and Na) encapsulated in silica and alumina gel (SG and AG), and their applications in organic syntheses. The methods elucidated involved the thermal incorporation of these metals into the pores of SG and AG, serving as solid-state reagents. The encapsulation method/approach addresses the problems associated with the high reactivity of these metals that limit their synthetic utility in research laboratories, pharmaceutical, and manufacturing industries. These problems include their sensitivity to air and moisture, pyrophoricity, difficulty in handling, non-commercial availability, and instability of some of the organoalkali metals reagents. Herein, we describe the developments to synthesize alkali metal precursor (Li-AG) in solid form that offer safer organolithium reagents. This precursor reduces or eliminates the danger associated with the traditional handling of organolithium reagents stored in flammable organic solvents. The use of Li-AG to prepare and deliver organolithium reagents from organic halides and ethers, as needed especially for those that are commercially not available is put forward. In addition, exploration of additional applications of Na-SG and Na-AG reagents in the demethoxylation of Weinreb amides to secondary amines, and Bouveault-Blanc type reduction of amides to amines are described.

  18. Interaction of Cu(+) with cytosine and formation of i-motif-like C-M(+)-C complexes: alkali versus coinage metals.

    PubMed

    Gao, Juehan; Berden, Giel; Rodgers, M T; Oomens, Jos

    2016-03-14

    The Watson-Crick structure of DNA is among the most well-known molecular structures of our time. However, alternative base-pairing motifs are also known to occur, often depending on base sequence, pH, or the presence of cations. Pairing of cytosine (C) bases induced by the sharing of a single proton (C-H(+)-C) may give rise to the so-called i-motif, which occurs primarily in expanded trinucleotide repeats and the telomeric region of DNA, particularly at low pH. At physiological pH, silver cations were recently found to stabilize C dimers in a C-Ag(+)-C structure analogous to the hemiprotonated C-dimer. Here we use infrared ion spectroscopy in combination with density functional theory calculations at the B3LYP/6-311G+(2df,2p) level to show that copper in the 1+ oxidation state induces an analogous formation of C-Cu(+)-C structures. In contrast to protons and these transition metal ions, alkali metal ions induce a different dimer structure, where each ligand coordinates the alkali metal ion in a bidentate fashion in which the N3 and O2 atoms of both cytosine ligands coordinate to the metal ion, sacrificing hydrogen-bonding interactions between the ligands for improved chelation of the metal cation.

  19. Structures of Hydrated Alkali Metal Cations, M+(H2O)nAr (m = Li, Na, K, rb and Cs, n = 3-5), Using Infrared Photodissociation Spectroscopy and Thermodynamic Analysis

    NASA Astrophysics Data System (ADS)

    Ke, Haochen; van der Linde, Christian; Lisy, James M.

    2014-06-01

    Alkali metal cations play vital roles in chemical and biochemical systems. Lithium is widely used in psychiatric treatment of manic states and bipolar disorder; Sodium and potassium are essential elements, having major biological roles as electrolytes, balancing osmotic pressure on body cells and assisting the electroneurographic signal transmission; Rubidium has seen increasing usage as a supplementation for manic depression and depression treatment; Cesium doped compounds are used as essential catalysts in chemical production and organic synthesis. Since hydrated alkali metal cations are ubiquitous and the basic form of the alkali metal cations in chemical and biochemical systems, their structural and thermodynamic properties serve as the foundation for modeling more complex chemical and biochemical processes, such as ion transport and ion size-selectivity of ionophores and protein channels. By combining mass spectrometry and infrared photodissociation spectroscopy, we have characterized the structures and thermodynamic properties of the hydrated alkali metal cations, i.e. M+(H2O)nAr, (M = Li, Na, K, Rb and Cs, n = 3-5). Ab initio calculations and RRKM-EE (evaporative ensemble) calculations were used to assist in the spectral assignments and thermodynamic analysis. Results showed that the structures of hydrated alkali metal cations were determined predominantly by the competition between non-covalent interactions, i.e. the water---water hydrogen bonding interactions and the water---cation electrostatic interactions. This balance, however, is very delicate and small changes, i.e. different cations, different levels of hydration and different effective temperatures clearly impact the balance.

  20. Coated Metal Articles and Method of Making

    DOEpatents

    Boller, Ernest R.; Eubank, Lowell D.

    2004-07-06

    The method of protectively coating metallic uranium which comprises dipping the metallic uranium in a molten alloy comprising about 20-75% of copper and about 80-25% of tin, dipping the coated uranium promptly into molten tin, withdrawing it from the molten tin and removing excess molten metal, thereupon dipping it into a molten metal bath comprising aluminum until it is coated with this metal, then promptly withdrawing it from the bath.

  1. Reactive collisions of sulfur dioxide with molten carbonates

    PubMed Central

    Krebs, Thomas; Nathanson, Gilbert M.

    2010-01-01

    Molecular beam scattering experiments are used to investigate reactions of SO2 at the surface of a molten alkali carbonate eutectic at 683 K. We find that two-thirds of the SO2 molecules that thermalize at the surface of the melt are converted to gaseous CO2 via the reaction . The CO2 product is formed from SO2 in less than 10-6 s, implying that the reaction takes place in a shallow liquid region less than 100 Å deep. The reaction probability does not vary between 683 and 883 K, further implying a compensation between decreasing SO2 residence time in the near-interfacial region and increasing reactivity at higher temperatures. These results demonstrate the remarkable efficiency of SO2 → CO2 conversion by molten carbonates, which appear to be much more reactive than dry calcium carbonate or wet slurries commonly used for flue gas desulfurization in coal-burning power plants. PMID:20133648

  2. Alkali-earth metal bridges formed in biofilm matrices regulate the uptake of fluoroquinolone antibiotics and protect against bacterial apoptosis.

    PubMed

    Kang, Fuxing; Wang, Qian; Shou, Weijun; Collins, Chris D; Gao, Yanzheng

    2017-01-01

    Bacterially extracellular biofilms play a critical role in relieving toxicity of fluoroquinolone antibiotic (FQA) pollutants, yet it is unclear whether antibiotic attack may be defused by a bacterial one-two punch strategy associated with metal-reinforced detoxification efficiency. Our findings help to assign functions to specific structural features of biofilms, as they strongly imply a molecularly regulated mechanism by which freely accessed alkali-earth metals in natural waters affect the cellular uptake of FQAs at the water-biofilm interface. Specifically, formation of alkali-earth-metal (Ca 2+ or Mg 2+ ) bridge between modeling ciprofloxacin and biofilms of Escherichia coli regulates the trans-biofilm transport rate of FQAs towards cells (135-nm-thick biofilm). As the addition of Ca 2+ and Mg 2+ (0-3.5 mmol/L, CIP: 1.25 μmol/L), the transport rates were reduced to 52.4% and 63.0%, respectively. Computational chemistry analysis further demonstrated a deprotonated carboxyl in the tryptophan residues of biofilms acted as a major bridge site, of which one side is a metal and the other is a metal girder jointly connected to the carboxyl and carbonyl of a FQA. The bacterial growth rate depends on the bridging energy at anchoring site, which underlines the environmental importance of metal bridge formed in biofilm matrices in bacterially antibiotic resistance. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Metal-mediated aminocatalysis provides mild conditions: Enantioselective Michael addition mediated by primary amino catalysts and alkali-metal ions

    PubMed Central

    Leven, Matthias; Neudörfl, Jörg M

    2013-01-01

    Summary Four catalysts based on new amides of chiral 1,2-diamines and 2-sulfobenzoic acid have been developed. The alkali-metal salts of these betaine-like amides are able to form imines with enones, which are activated by Lewis acid interaction for nucleophilic attack by 4-hydroxycoumarin. The addition of 4-hydroxycoumarin to enones gives ee’s up to 83% and almost quantitative yields in many cases. This novel type of catalysis provides an effective alternative to conventional primary amino catalysis were strong acid additives are essential components. PMID:23400419

  4. PLUTONIUM ELECTROREFINING CELLS

    DOEpatents

    Mullins, L.J. Jr.; Leary, J.A.; Bjorklund, C.W.; Maraman, W.J.

    1963-07-16

    Electrorefining cells for obtaining 99.98% plutonium are described. The cells consist of an impure liquid plutonium anode, a molten PuCl/sub 3/-- alkali or alkaline earth metal chloanode, a molten PuCl/sub 3/-alkali or alkaline earth metal chloride electrolyte, and a nonreactive cathode, all being contained in nonreactive ceramic containers which separate anode from cathode by a short distance and define a gap for the collection of the purified liquid plutonium deposited on the cathode. Important features of these cells are the addition of stirrer blades on the anode lead and a large cathode surface to insure a low current density. (AEC)

  5. Production of chlorine from chloride salts

    DOEpatents

    Rohrmann, Charles A.

    1981-01-01

    A process for converting chloride salts and sulfuric acid to sulfate salts and elemental chlorine is disclosed. A chloride salt and sulfuric acid are combined in a furnace where they react to produce a sulfate salt and hydrogen chloride. Hydrogen chloride from the furnace contacts a molten salt mixture containing an oxygen compound of vanadium, an alkali metal sulfate and an alkali metal pyrosulfate to recover elemental chlorine. In the absence of an oxygen-bearing gas during the contacting, the vanadium is reduced, but is regenerated to its active higher valence state by separately contacting the molten salt mixture with an oxygen-bearing gas.

  6. Lifetime of Sodium Beta-Alumina Membranes in Molten Sodium Hydroxide

    DTIC Science & Technology

    2008-07-01

    ABSTRACT Summary: Sodium metal can be made by electrolysis of molten sodium hydroxide in sodium beta-alumina membrane electrolysis cells... electrolysis of molten sodium hydroxide in sodium ”-alumina membrane electrolysis cells. However, there are some uncertainties about the lifetime of the...the properties of the membrane degrade upon long term contact with molten sodium hydroxide. Electrolysis cells were designed, but it proved

  7. Hydrogen generation using silicon nanoparticles and their mixtures with alkali metal hydrides

    NASA Astrophysics Data System (ADS)

    Patki, Gauri Dilip

    mole of Si. We compare our silicon nanoparticles (˜10nm diameter) with commercial silicon nanopowder (<100nm diameter) and ball-milled silicon powder (325 mesh). The increase in rate upon decreasing the particle size to 10 nm was even greater than would be expected based upon the increase in surface area. While specific surface area increased by a factor of 6 in going from <100 nm to ˜10 nm particles, the hydrogen production rate increased by a factor of 150. However, in all cases, silicon requires a base (e.g. NaOH, KOH, hydrazine) to catalyze its reaction with water. Metal hydrides are also promising hydrogen storage materials. The optimum metal hydride would possess high hydrogen storage density at moderate temperature and pressure, release hydrogen safely and controllably, and be stable in air. Alkali metal hydrides have high hydrogen storage density, but exhibit high uncontrollable reactivity with water. In an attempt to control this explosive nature while maintaining high storage capacity, we mixed our silicon nanoparticles with the hydrides. This has dual benefits: (1) the hydride- water reaction produces the alkali hydroxide needed for base-catalyzed silicon oxidation, and (2) dilution with 10nm coating by, the silicon may temper the reactivity of the hydride, making the process more controllable. Initially, we analyzed hydrolysis of pure alkali metal hydrides and alkaline earth metal hydrides. Lithium hydride has particularly high hydrogen gravimetric density, along with faster reaction kinetics than sodium hydride or magnesium hydride. On analysis of hydrogen production we found higher hydrogen yield from the silicon nanoparticle—metal hydride mixture than from pure hydride hydrolysis. The silicon-hydride mixtures using our 10nm silicon nanoparticles produced high hydrogen yield, exceeding the theoretical yield. Some evidence of slowing of the hydride reaction rate upon addition of silicon nanoparticles was observed.

  8. Heating rates in collisionally opaque alkali-metal atom traps: Role of secondary collisions

    NASA Astrophysics Data System (ADS)

    Beijerinck, H. C. W.

    2000-12-01

    Grazing collisions with background gas are the major cause of trap loss and trap heating in atom traps. To first order, these effects do not depend on the trap density. In collisionally opaque trapped atom clouds, however, scattered atoms with an energy E larger than the effective trap depth Eeff, which are destined to escape from the atom cloud, will have a finite probability for a secondary collision. This results in a contribution to the heating rate that depends on the column density of the trapped atoms, i.e., the product of density and characteristic size of the trap. For alkali-metal atom traps, secondary collisions are quite important due to the strong long-range interaction with like atoms. We derive a simple analytical expression for the secondary heating rate, showing a dependency proportional to E1/2eff. When extrapolating to a vanishing column density, only primary collisions with the background gas will contribute to the heating rate. This contribution is rather small, due to the weak long-range interaction of the usual background gas species in an ultrahigh-vacuum system-He, Ne, or Ar-with the trapped alkali-metal atoms. We conclude that the transition between trap-loss collisions and heating collisions is determined by a cutoff energy 200 μK<=Eeff<=400 μK, much smaller than the actual trap depth E in most magnetic traps. Atoms with an energy Eeffalkali-metal atoms Li through Cs as a function of the effective trap depth, the column density of the trap, and the species in the background gas. The predictions of our model are in good agreement with the experimental data of Myatt for heating rates in high-density 87Rb-atom magnetic traps at JILA, including the effect of the rf shield and the composition of the background gas. It is shown that collisions with atoms from the Oort

  9. METAL PRODUCTION AND CASTING

    DOEpatents

    Magel, T.T.

    1958-03-01

    This patent covers a method and apparatus for collecting the molten metal produced by high temperature metal salt reduction. It consists essentially of subjecting the reaction vessel to centrifugal force in order to force the liberatcd molten metal into a coherent molten mass, and allowing it to solidify there. The apparatus is particularly suitable for use with small quantities of rare metals.

  10. Ceramics for Molten Materials Transfer

    NASA Technical Reports Server (NTRS)

    Standish, Evan; Stefanescu, Doru M.; Curreri, Peter A.

    2009-01-01

    The paper reviews the main issues associated with molten materials transfer and handling on the lunar surface during the operation of a hig h temperature electrowinning cell used to produce oxygen, with molten iron and silicon as byproducts. A combination of existing technolog ies and purposely designed technologies show promise for lunar exploi tation. An important limitation that requires extensive investigation is the performance of refractory currently used for the purpose of m olten metal containment and transfer in the lunar environment associa ted with electrolytic cells. The principles of a laboratory scale uni t at a scale equivalent to the production of 1 metric ton of oxygen p er year are introduced. This implies a mass of molten materials to be transferred consistent with the equivalent of 1kg regolithlhr proces sed.

  11. Intracellular acidification-induced alkali metal cation/H+ exchange in human neutrophils

    PubMed Central

    1987-01-01

    Pretreatment of isolated human neutrophils (resting pHi congruent to 7.25 at pHo 7.40) with 30 mM NH4Cl for 30 min leads to an intracellular acidification (pHi congruen to 6.60) when the NH4Cl prepulse is removed. Thereafter, in 140 mM Na+ medium, pHi recovers exponentially with time (initial rate, approximately 0.12 pH/min) to reach the normal resting pHi by approximately 20 min, a process that is accomplished mainly, if not exclusively, though an exchange of internal H+ for external Na+. This Na+/H+ countertransport is stimulated by external Na+ (Km congruent to 21 mM) and by external Li+ (Km congruent to 14 mM), though the maximal transport rate for Na+ is about twice that for Li+. Both Na+ and Li+ compete as substrates for the same translocation sites on the exchange carrier. Other alkali metal cations, such as K+, Rb+, or Cs+, do not promote pHi recovery, owing to an apparent lack of affinity for the carrier. The exchange system is unaffected by ouabain or furosemide, but can be competitively inhibited by the diuretic amiloride (Ki congruent to 8 microM). The influx of Na+ or Li+ is accompanied by an equivalent counter-reflux of H+, indicating a 1:1 stoichiometry for the exchange reaction, a finding consistent with the lack of voltage sensitivity (i.e., electroneutrality) of pHi recovery. These studies indicate that the predominant mechanism in human neutrophils for pHi regulation after intracellular acidification is an amiloride-sensitive alkali metal cation/H+ exchange that shares a number of important features with similar recovery processes in a variety of other mammalian cell types. PMID:3694176

  12. Release from ISOLDE molten metal targets under pulsed proton beam conditions

    NASA Astrophysics Data System (ADS)

    Lettry, J.; Catherall, R.; Cyvoct, G.; Evensen, A. H. M.; Lindroos, M.; Jonsson, O. C.; Kugler, E.; Schindl, K.; Ravn, H.; Wildner, E.; Drumm, P.; Obert, J.; Putaux, J. C.; Sauvage, J.

    1996-04-01

    By moving the ISOLDE mass separators from the 600 MeV Synchrocyclotron (SC) to the 1 GeV Proton-Synchrotron-Booster (PS) the instantaneous energy density of the proton beam went up by 3 orders of magnitude. The developments of the molten metal target units and the optimization of the PS proton beam to cope with the effects of the thermal shocks induced by the proton beam are described. The energy density of the PS proton beam was reduced by spatial defocusing and time staggered extraction of the four PS-accelerators. The release from lanthanum, lead and tin targets is discussed for different settings of the proton beam and compared to the release observed at ISOLDE-SC. The yields of Hg isotopes are presented.

  13. James C. McGroddy Prize Talk: Superconductivity in alkali-metal doped Carbon-60

    NASA Astrophysics Data System (ADS)

    Hebard, Arthur

    2008-03-01

    Carbon sixty (C60), which was first identified in 1985 in laser desorption experiments, is unquestionably an arrestingly beautiful molecule. The high symmetry of the 12 pentagonal and 20 hexagonal faces symmetrically arrayed in a soccer-ball like structure invites special attention and continues to stimulate animated speculation. The availability in 1990 of macroscopic amounts of purified C60 derived from carbon-arc produced soot allowed the growth and characterization of both bulk and thin-film samples. Crystalline C60 is a molecular solid held together by weak van der Waals forces. The fcc structure has a 74% packing fraction thus allowing ample opportunity (26% available volume) for the intercalation of foreign atoms into the interstitial spaces of the three dimensional host. This opportunity catalyzed much of the collaborative work amongst chemists, physicists and materials scientists at Bell Laboratories, and resulted in the discovery of superconductivity in alkali-metal doped C60 with transition temperatures (Tc) in the mid-30-kelvin range. In this talk I will review how the successes of this initial team effort stimulated a worldwide collaboration between experimentalists and theorists to understand the promise and potential of an entirely new class of superconductors containing only two elements, carbon and an intercalated alkali metal. Although the cuprates still hold the record for the highest Tc, there are still open scientific questions about the mechanism that gives rise to such unexpectedly high Tc's in the non-oxide carbon-based superconductors. The doped fullerenes have unusual attributes (e.g., narrow electronic bands, high disorder, anomalous energy scales, and a tantalizing proximity to a metal-insulator Mott transition), which challenge conventional thinking and at the same time provide useful insights into new directions for finding even higher Tc materials. The final chapter of the `soot to superconductivity' story has yet to be written.

  14. The role of oxygen in porous molybdenum electrodes for the alkali metal thermoelectric converter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Williams, R.M.; Nagasubramanian, G.; Khanna, S.K.

    1986-08-01

    The alkali metal thermoelectric converter is a direct energy conversion device, utilizing a high alkali metal activity gradient to generate electrical power. Its operation is based on the unique ion conductive properties of beta''-alumina solid electrolyte. The major barrier to application of this device is identification of an electrode which can maintain optimum power densities for operation times of >10,000h. Thin, porous molybdenum electrodes have shown the best performance characteristics, but show a variety of time dependent phenomena, including eventual degradation to power densities 3-5 times lower than initial values. Several Na-Mo-O compounds, including Na/sub 2/MoO/sub 4/ and Na/sub 2/Mo/submore » 3/O/sub 6/, are formed during AMTEC operation. These compounds may be responsible for enhanced Na transport through Mo electrodes via sodium ion conduction, and eventual performance degradation due to their volatilization and decomposition. No decomposition of beta''-alumina has been observed under simulated AMTEC operating conditions up to 1373 K. In this paper, we present a model for chemical reactions occurring in porous molybdenum electrodes. The model is based on thermochemical and kinetic data, known sodium-molybdenum-oxygen chemistry, x-ray diffraction analysis of molybdenum and molybdenum oxide electrodes, and the electrochemical behavior of the cell.« less

  15. Neutral glycoconjugated amide-based calix[4]arenes: complexation of alkali metal cations in water.

    PubMed

    Cindro, Nikola; Požar, Josip; Barišić, Dajana; Bregović, Nikola; Pičuljan, Katarina; Tomaš, Renato; Frkanec, Leo; Tomišić, Vladislav

    2018-02-07

    Cation complexation in water presents a unique challenge in calixarene chemistry, mostly due to the fact that a vast majority of calixarene-based cation receptors is not soluble in water or their solubility has been achieved by introducing functionalities capable of (de)protonation. Such an approach inevitably involves the presence of counterions which compete with target cations for the calixarene binding site, and also rather often requires the use of ion-containing buffer solutions in order to control the pH. Herein we devised a new strategy towards the solution of this problem, based on introducing carbohydrate units at the lower or upper rim of calix[4]arenes which comprise efficient cation binding sites. In this context, we prepared neutral, water-soluble receptors with secondary or tertiary amide coordinating groups, and studied their complexation with alkali metal cations in aqueous and methanol (for the comparison purpose) solutions. Complexation thermodynamics was quantitatively characterized by UV spectrometry and isothermal titration calorimetry, revealing that one of the prepared tertiary amide derivatives is capable of remarkably efficient (log K ≈ 5) and selective binding of sodium cations among alkali metal cations in water. Given the ease of the synthetic procedure used, and thus the variety of accessible analogues, this study can serve as a platform for the development of reagents for diverse purposes in aqueous media.

  16. Rare-gas impurities in alkali metals: Relation to optical absorption

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Meltzer, D.E.; Pinski, F.J.; Stocks, G.M.

    1988-04-15

    An investigation of the nature of rare-gas impurity potentials in alkali metals is performed. Results of calculations based on simple models are presented, which suggest the possibility of resonance phenomena. These could lead to widely varying values for the exponents which describe the shape of the optical-absorption spectrum at threshold in the Mahan--Nozieres--de Dominicis theory. Detailed numerical calculations are then performed with the Korringa-Kohn-Rostoker coherent-potential-approximation method. The results of these highly realistic calculations show no evidence for the resonance phenomena, and lead to predictions for the shape of the spectra which are in contradiction to observations. Absorption and emission spectramore » are calculated for two of the systems studied, and their relation to experimental data is discussed.« less

  17. Determination of thermal physical properties of alkali fluoride/carbonate eutectic molten salt

    NASA Astrophysics Data System (ADS)

    An, Xue-Hui; Cheng, Jin-Hui; Su, Tao; Zhang, Peng

    2017-06-01

    Molten salts used in high temperatures are more and more interested in the CSP for higher energy conversion efficiency. Thermal physical properties are the basic engineering data of thermal hydraulic calculation and safety analysis. Therefore, the thermophysical performances involving density, specific heat capacity, viscosity and thermal conductivity of FLiNaK, (LiNaK)2CO3 and LiF(NaK)2CO3 molten salts are experimentally determined and through comparison the general rules can be summarized. Density measurement was performed on the basis of Archimedes theory; specific heat capacity was measured using the DSC technique; viscosity was tested based on the rotating method; and the thermal conductivity was gained by laser flash method with combination of the density, specific heat capacity and thermal diffusivity through a formula. Finally, the energy storage capacity and figures of merit are calculated to evaluate their feasibility as TES and HFT media. The results show that FLiNaK has the largest energy storage capacity and best heat transfer performance, LiF(NaK)2CO3 is secondary, and (LiNaK)2CO3 has the smallest.

  18. Investigation of molten pool oscillation during GMAW-P process based on a 3D model

    NASA Astrophysics Data System (ADS)

    Wang, L. L.; Lu, F. G.; Cui, H. C.; Tang, X. H.

    2014-11-01

    In order to better reveal the oscillation mechanism of the pulsed gas metal arc welding (GMAW-P) process due to an alternately varied welding current, arc plasma and molten pool oscillation were simulated through a self-consistent three-dimensional model. Based on an experimental analysis of the dynamic variation of the arc plasma and molten pool captured by a high-speed camera, the model was validated by comparison of the measured and predicted results. The calculated results showed that arc pressure was the key factor causing the molten pool to oscillate. The variation in arc size and temperature from peak time to base time resulted in a great difference in the heat input and arc pressure acting on the molten pool. The surface deformation of the molten pool due to the varying degrees of arc pressure induced alternate displacement and backflow in the molten metal. The periodic iteration of deeper and shallower surface deformation, drain and backflow of molten metal caused the molten pool to oscillate at a certain frequency. In this condition, the arc pressure at the peak time is more than six times higher than that at the base time, and the maximum surface depression is 1.4 mm and 0.6 mm, respectively, for peak time and base time.

  19. A Quantitative Tunneling/Desorption Model for the Exchange Current at the Porous Electrode/Beta - Alumina/Alkali Metal Gas Three Phase Zone at 700-1300K

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Ryan, M. A.; Saipetch, C.; LeDuc, H. G.

    1996-01-01

    The exchange current observed at porous metal electrodes on sodium or potassium beta -alumina solid electrolytes in alkali metal vapor is quantitatively modeled with a multi-step process with good agreement with experimental results.

  20. Treatment of organic waste

    DOEpatents

    Grantham, LeRoy F.

    1979-01-01

    An organic waste containing at least one element selected from the group consisting of strontium, cesium, iodine and ruthenium is treated to achieve a substantial reduction in the volume of the waste and provide for fixation of the selected element in an inert salt. The method of treatment comprises introducing the organic waste and a source of oxygen into a molten salt bath maintained at an elevated temperature to produce solid and gaseous reaction products. The gaseous reaction products comprise carbon dioxide and water vapor, and the solid reaction products comprise the inorganic ash constituents of the organic waste and the selected element which is retained in the molten salt. The molten salt bath comprises one or more alkali metal carbonates, and may optionally include from 1 to about 25 wt.% of an alkali metal sulfate.

  1. Apparatus and method for stripping tritium from molten salt

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Holcomb, David E.; Wilson, Dane F.

    A method of stripping tritium from flowing stream of molten salt includes providing a tritium-separating membrane structure having a porous support, a nanoporous structural metal-ion diffusion barrier layer, and a gas-tight, nonporous palladium-bearing separative layer, directing the flowing stream of molten salt into contact with the palladium-bearing layer so that tritium contained within the molten salt is transported through the tritium-separating membrane structure, and contacting a sweep gas with the porous support for collecting the tritium.

  2. Monitoring of photoluminescence decay by alkali and alkaline earth metal cations using a photoluminescent bolaamphiphile self-assembly as an optical probe.

    PubMed

    Kim, Sunhyung; Kwak, Jinyoung; Lee, Sang-Yup

    2014-05-01

    Photoluminescence (PL) decay induced by the displacement of an ionic fluorescence component, Tb(3+), with alkali and alkaline earth metal cations was investigated using photoluminescent spherical self-assemblies as optical probes. The photoluminescent spherical self-assembly was prepared by the self-organization of a tyrosine-containing bolaamphiphile molecule with a photosensitizer and Tb(3+) ion. The lanthanide ion, Tb(3+), electrically bound to the carboxyl group of the bolaamphiphile molecule, was displaced by alkali and alkaline earth metal cations that had stronger electrophilicity. The PL of the self-assembly decayed remarkably due to the substitution of lanthanide ions with alkali and alkaline earth metal cations. The PL decay showed a positive correlation with cation concentration and was sensitive to the cation valency. Generally, the PL decay was enhanced by the electrophilicity of the cations. However, Ca(2+) showed greater PL decay than Mg(2+) because Ca(2+) could create various complexes with the carboxyl groups of the bolaamphiphile molecule. Microscopic and spectroscopic investigations were conducted to study the photon energy transfer and displacement of Tb(3+) by the cation exchange. This study demonstrated that the PL decay by the displacement of the ionic fluorescent compound was applied to the detection of various cations in aqueous media and is applicable to the development of future optical sensors. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Rydberg States of Alkali Metal Atoms on Superfluid Helium Droplets - Theoretical Considerations

    NASA Astrophysics Data System (ADS)

    Pototschnig, Johann V.; Lackner, Florian; Hauser, Andreas W.; Ernst, Wolfgang E.

    2017-06-01

    The bound states of electrons on the surface of superfluid helium have been a research topic for several decades. One of the first systems treated was an electron bound to an ionized helium cluster. Here, a similar system is considered, which consists of a helium droplet with an ionized dopant inside and an orbiting electron on the outside. In our theoretical investigation we select alkali metal atoms (AK) as central ions, stimulated by recent experimental studies of Rydberg states for Na, Rb, and Cs attached to superfluid helium nanodroplets. Experimental spectra , obtained by electronic excitation and subsequent ionization, showed blueshifts for low lying electronic states and redshifts for Rydberg states. In our theoretical treatment the diatomic AK^+-He potential energy curves are first computed with ab initio methods. These potentials are then used to calculate the solvation energy of the ion in a helium droplet as a function of the number of atoms. Additional potential terms, derived from the obtained helium density distribution, are added to the undisturbed atomic pseudopotential in order to simulate a 'modified' potential felt by the outermost electron. This allows us to compute a new set of eigenstates and eigenenergies, which we compare to the experimentally observed energy shifts for highly excited alkali metal atoms on helium nanodroplets. A. Golov and S. Sekatskii, Physica B, 1994, 194, 555-556 E. Loginov, C. Callegari, F. Ancilotto, and M. Drabbels, J. Phys. Chem. A, 2011, 115, 6779-6788 F. Lackner, G. Krois, M. Koch, and W. E. Ernst, J. Phys. Chem. Lett., 2012, 3, 1404-1408 F. Lackner, G. Krois, M. Theisen, M. Koch, and W. E. Ernst, Phys. Chem. Chem. Phys., 2011, 13, 18781-18788

  4. Method of producing homogeneous mixed metal oxides and metal-metal oxide mixtures

    DOEpatents

    Quinby, Thomas C.

    1978-01-01

    Metal powders, metal oxide powders, and mixtures thereof of controlled particle size are provided by reacting an aqueous solution containing dissolved metal values with excess urea. Upon heating, urea reacts with water from the solution leaving a molten urea solution containing the metal values. The molten urea solution is heated to above about 180.degree. C. whereupon metal values precipitate homogeneously as a powder. The powder is reduced to metal or calcined to form oxide particles. One or more metal oxides in a mixture can be selectively reduced to produce metal particles or a mixture of metal and metal oxide particles.

  5. Effect of charging on silicene with alkali metal atom adsorption

    NASA Astrophysics Data System (ADS)

    Li, Manman; Li, Zhongyao; Gong, Shi-Jing

    2018-02-01

    Based on first-principles calculations, we studied the effects of charging on the structure, binding energy and electronic properties of silicene with alkali metal (AM) atom (Li, Na or K) adsorption. In AMSi2, electron doping enlarges the lattice constant of silicene, while the influence of hole doping is non-monotonic. In AMSi8, the lattice constant increases/decreases almost linearly with the increase in electron/hole doping. In addition, the AM-Si vertical distance can be greatly enlarged by excessive hole doping in both AMSi2 and AMSi8 systems. When the hole doping is as large as  +e per unit cell, both AMSi2 and AMSi8 can be transformed from metal to semiconductor. However, the binding energy would be negative in the AM+ Si2 semiconductor. It suggests AM+ Si2 is unstable in this case. In addition, the electron doping and the AM-Si vertical distance would greatly influence the band gap of silicene in LiSi8 and NaSi8, while the band gap in KSi8 is relatively stable. Therefore, KSi8 may be a more practicable material in nanotechnology.

  6. H-1 NMR study of ternary ammonia-alkali metal-graphite intercalation compounds

    NASA Technical Reports Server (NTRS)

    Tsang, T.; Fronko, R. M.; Resing, H. A.; Qian, X. W.; Solin, S. A.

    1987-01-01

    For the first-stage ternary ammonia-alkali metal-graphite intercalation compounds M(NH3)(x)C24(x of about 4, M = K, Rb, Cs), three sets of triplet H-1 NMR spectral lines have been observed at various temperatures and orientations due to the H-1 - H-1 and N-14 - H-1 dipolar interactions. The structures of these compounds have been inferred as mobile (liquid-like) intercalant layers of planar M(NH3)4 ions in between the carbon layers. For the intercalated ammonia molecules, the potential barrier is about 0.2 eV and the molecular geometry is very close to the free NH3 in gas phase.

  7. Reversible electro-optic device employing aprotic molten salts and method

    DOEpatents

    Warner, Benjamin P [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM; Burrell, Anthony K [Los Alamos, NM; Hall, Simon B [Palmerston North, NZ

    2008-01-08

    A single-compartment reversible mirror device having a solution of aprotic molten salt, at least one soluble metal-containing species comprising metal capable of being electrodeposited, and at least one anodic compound capable of being oxidized was prepared. The aprotic molten salt is liquid at room temperature and includes lithium and/or quaternary ammonium cations, and anions selected from trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). A method for preparing substantially pure molten salts is also described.

  8. Reversible Electro-Optic Device Employing Aprotic Molten Salts And Method

    DOEpatents

    Warner, Benjamin P.; McCleskey, T. Mark; Burrell, Anthony K.; Hall, Simon B.

    2005-03-01

    A single-compartment reversible mirror device having a solution of aprotic molten salt, at least one soluble metal-containing species comprising metal capable of being electrodeposited, and at least one anodic compound capable of being oxidized was prepared. The aprotic molten salt is liquid at room temperature and includes lithium and/or quaternary ammonium cations, and anions selected from trifluoromethylsulfonate (CF.sub.3 SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3 SO.sub.2).sub.2 N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3 CF.sub.2 SO.sub.2).sub.2 N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3 SO.sub.2).sub.3 C.sup.-). A method for preparing substantially pure molten salts is also described.

  9. Control of wavepacket dynamics in mixed alkali metal clusters by optimally shaped fs pulses

    NASA Astrophysics Data System (ADS)

    Bartelt, A.; Minemoto, S.; Lupulescu, C.; Vajda, Š.; Wöste, L.

    We have performed adaptive feedback optimization of phase-shaped femtosecond laser pulses to control the wavepacket dynamics of small mixed alkali-metal clusters. An optimization algorithm based on Evolutionary Strategies was used to maximize the ion intensities. The optimized pulses for NaK and Na2K converged to pulse trains consisting of numerous peaks. The timing of the elements of the pulse trains corresponds to integer and half integer numbers of the vibrational periods of the molecules, reflecting the wavepacket dynamics in their excited states.

  10. Alkali metals levels in the human brain tissue: Anatomical region differences and age-related changes.

    PubMed

    Ramos, Patrícia; Santos, Agostinho; Pinto, Edgar; Pinto, Nair Rosas; Mendes, Ricardo; Magalhães, Teresa; Almeida, Agostinho

    2016-12-01

    The link between trace elements imbalances (both "toxic" and "essential") in the human brain and neurodegenerative disease has been subject of extensive research. More recently, some studies have highlighted the potential role of the homeostasis deregulation of alkali metals in specific brain regions as key factor in the pathogenesis of neurodegenerative diseases such as multiple sclerosis and Alzheimer's disease. Using flame atomic emission spectrometry and inductively coupled plasma-mass spectrometry after microwave-assisted acid digestion of the samples, alkali metals (Na, K, Li, Rb and Cs) were determined in 14 different areas of the human brain (frontal cortex, superior and middle temporal gyri, caudate nucleus, putamen, globus pallidus, cingulated gyrus, hippocampus, inferior parietal lobule, visual cortex of the occipital lobe, midbrain, pons, medulla and cerebellum) of adult individuals (n=42; 71±12, range: 50-101 years old) with no known history and evidence of neurodegenerative, neurological or psychiatric disorder. Potassium was found as the most abundant alkali metal, followed by Na, Rb, Cs and Li. Lithium, K and Cs distribution showed to be quite heterogeneous. On the contrary, Rb and Na appeared quite homogeneously distributed within the human brain tissue. The lowest levels of Na, K, Rb and Li were found in the brainstem (midbrain, medulla and pons) and cerebellum, while the lowest levels of Cs were found in the frontal cortex. The highest levels of K (mean±sd; range 15.5±2.5; 8.9-21.8mg/g) Rb (17.2±6.1; 3.9-32.4μg/g and Cs (83.4±48.6; 17.3-220.5ng/g) were found in putamen. The highest levels of Na and Li were found in the frontal cortex (11.6±2.4; 6.6-17.1mg/g) and caudate nucleus (7.6±4.6 2.2-21.3ng/g), respectively. Although K, Cs and Li levels appear to remain largely unchanged with age, some age-related changes were observed for Na and Rb levels in particular brain regions (namely in the hippocampus). Copyright © 2016 Elsevier GmbH. All

  11. Joule-Heated Molten Regolith Electrolysis Reactor Concepts for Oxygen and Metals Production on the Moon and Mars

    NASA Technical Reports Server (NTRS)

    Sibille, Laurent; Dominques, Jesus A.

    2012-01-01

    The maturation of Molten Regolith Electrolysis (MRE) as a viable technology for oxygen and metals production on explored planets relies on the realization of the self-heating mode for the reactor. Joule heat generated during regolith electrolysis creates thermal energy that should be able to maintain the molten phase (similar to electrolytic Hall-Heroult process for aluminum production). Self-heating via Joule heating offers many advantages: (1) The regolith itself is the crucible material, it protects the vessel walls (2) Simplifies the engineering of the reactor (3) Reduces power consumption (no external heating) (4) Extends the longevity of the reactor. Predictive modeling is a tool chosen to perform dimensional analysis of a self-heating reactor: (1) Multiphysics modeling (COMSOL) was selected for Joule heat generation and heat transfer (2) Objective is to identify critical dimensions for first reactor prototype.

  12. Alkali metal thermal to electric conversion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sievers, R.K.; Ivanenok, J.F. III; Hunt, T.K.

    1995-10-01

    With potential efficiencies of up to 40%, AMTEC technology offers reliability and fuel flexibility for aerospace and ground power applications. Alkali Metal Thermal to Electric Conversion (AMTEC), a direct power-conversion technology, is emerging from the laboratory for use in a number of applications that require lightweight, long-running, efficient power systems. AMTEC is compatible with many heat and fuel sources, and it offers the reliability of direct (that is, no moving parts) thermal to electric conversion. These features make it an attractive technology for small spacecraft used in deep-space missions and for ground power applications, such as self-powered furnaces and themore » generators used in recreational vehicles. Researchers at Ford Scientific Laboratories, in Dearborn, Michigan, first conceived AMTEC technology in 1968 when they identified and patented a converter known as the sodium heat engine. This heat engine was based on the unique properties of {beta}-alumina solid electrolyte (BASE), a ceramic material that is an excellent sodium ion conductor but a poor electronic conductor. BASE was used to form a structural barrier across which a sodium concentration gradient could be produced from thermal energy. The engine provided a way to isothermally expand sodium through the BASE concentration gradient without moving mechanical components. Measured power density and calculated peak efficiencies were impressive, which led to funding from the Department of Energy for important material technology development.« less

  13. Electrolytic purification of metals

    DOEpatents

    Bowman, Kenneth A.

    1980-01-01

    A method of electrolytically separating metal from impurities comprises providing the metal and impurities in a molten state in a container having a porous membrane therein, the membrane having a thickness in the range of about 0.01 to 0.1 inch, being capable of containing the molten metal in the container, and being permeable by a molten electrolyte. The metal is electrolytically transferred through the membrane to a cathode in the presence of the electrolyte for purposes of separating or removing impurities from the metal.

  14. [Bio-oil production from biomass pyrolysis in molten salt].

    PubMed

    Ji, Dengxiang; Cai, Tengyue; Ai, Ning; Yu, Fengwen; Jiang, Hongtao; Ji, Jianbing

    2011-03-01

    In order to investigate the effects of pyrolysis conditions on bio-oil production from biomass in molten salt, experiments of biomass pyrolysis were carried out in a self-designed reactor in which the molten salt ZnCl2-KCl (with mole ratio 7/6) was selected as heat carrier, catalyst and dispersion agent. The effects of metal salt added into ZnCl2-KCl and biomass material on biomass pyrolysis were discussed, and the main compositions of bio-oil were determined by GC-MS. Metal salt added into molten salt could affect pyrolysis production yields remarkably. Lanthanon salt could enhance bio-oil yield and decrease water content in bio-oil, when mole fraction of 5.0% LaCl3 was added, bio-oil yield could reach up to 32.0%, and water content of bio-oil could reduce to 61.5%. The bio-oil and char yields were higher when rice straw was pyrolysed, while gas yield was higher when rice husk was used. Metal salts showed great selectivity on compositions of bio-oil. LiCl and FeCl2 promoted biomass to pyrolyse into smaller molecular weight compounds. CrCl3, CaCl2 and LaCl3 could restrain second pyrolysis of bio-oil. The research provided a scientific reference for production of bio-oil from biomass pyrolysis in molten salt.

  15. Metal atomization spray nozzle

    DOEpatents

    Huxford, Theodore J.

    1993-01-01

    A spray nozzle for a magnetohydrodynamic atomization apparatus has a feed passage for molten metal and a pair of spray electrodes mounted in the feed passage. The electrodes, diverging surfaces which define a nozzle throat and diverge at an acute angle from the throat. Current passes through molten metal when fed through the throat which creates the Lorentz force necessary to provide atomization of the molten metal.

  16. Carbonation of metal silicates for long-term CO2 sequestration

    DOEpatents

    Blencoe, James G; Palmer, Donald A; Anovitz, Lawrence M; Beard, James S

    2014-03-18

    In a preferred embodiment, the invention relates to a process of sequestering carbon dioxide. The process comprises the steps of: (a) reacting a metal silicate with a caustic alkali-metal hydroxide to produce a hydroxide of the metal formerly contained in the silicate; (b) reacting carbon dioxide with at least one of a caustic alkali-metal hydroxide and an alkali-metal silicate to produce at least one of an alkali-metal carbonate and an alkali-metal bicarbonate; and (c) reacting the metal hydroxide product of step (a) with at least one of the alkali-metal carbonate and the alkali-metal bicarbonate produced in step (b) to produce a carbonate of the metal formerly contained in the metal silicate of step (a).

  17. Closed cell metal foam method

    DOEpatents

    Patten, James W.

    1978-01-01

    Foamed metals and metal alloys which have a closed cellular structure are prepared by heating a metal body containing entrapped inert gas uniformly distributed throughout to a temperature above the melting point of the metal and maintaining the body at this temperature a period of time sufficient to permit the entrapped gas to expand, forming individual cells within the molten metal, thus expanding and foaming the molten metal. After cell formation has reached the desired amount, the foamed molten metal body is cooled to below the melting temperature of the metal. The void area or density of the foamed metal is controlled by predetermining the amount of inert gas entrapped in the metal body and by the period of time the metal body is maintained in the molten state. This method is useful for preparing foamed metals and metal alloys from any metal or other material of which a body containing entrapped inert gas can be prepared.

  18. Experimental study of copper-alkali ion exchange in glass

    NASA Astrophysics Data System (ADS)

    Gonella, F.; Caccavale, F.; Bogomolova, L. D.; D'Acapito, F.; Quaranta, A.

    1998-02-01

    Copper-alkali ion exchange was performed by immersing different silicate glasses (soda-lime and BK7) in different molten eutectic salt baths (CuSO4:Na2SO4 and CuSO4:K2SO4). The obtained optical waveguides were characterized by m-lines spectroscopy for the determination of refractive index profiles, and by secondary ion mass spectrometry for the concentration profiles of the ion species involved in the exchange process. The different oxidation states of copper inside the glass structure were studied by electron paramagnetic resonance and x-ray absorption techniques. Interdiffusion copper coefficients were also determined. The Cu-alkali exchange was observed to give rise to local structural rearrangement of the atoms in the glass matrix. The Cu+ ion was found to mainly govern the exchange process, while competition between Cu-Na and K-Na exchanges occurred when a potassium sulfate bath was used. In this case, significant waveguide modal birefringence was observed.

  19. Alkali Metal Cation Affinities of Anionic Main Group-Element Hydrides Across the Periodic Table.

    PubMed

    Boughlala, Zakaria; Fonseca Guerra, Célia; Bickelhaupt, F Matthias

    2017-10-05

    We have carried out an extensive exploration of gas-phase alkali metal cation affinities (AMCA) of archetypal anionic bases across the periodic system using relativistic density functional theory at ZORA-BP86/QZ4P//ZORA-BP86/TZ2P. AMCA values of all bases were computed for the lithium, sodium, potassium, rubidium and cesium cations and compared with the corresponding proton affinities (PA). One purpose of this work is to provide an intrinsically consistent set of values of the 298 K AMCAs of all anionic (XH n-1 - ) constituted by main group-element hydrides of groups 14-17 along the periods 2-6. In particular, we wish to establish the trend in affinity for a cation as the latter varies from proton to, and along, the alkali cations. Our main purpose is to understand these trends in terms of the underlying bonding mechanism using Kohn-Sham molecular orbital theory together with a quantitative bond energy decomposition analyses (EDA). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Reprocessing of LiH in Molten Chlorides

    NASA Astrophysics Data System (ADS)

    Masset, Patrick J.; Gabriel, Armand; Poignet, Jean-Claude

    2008-06-01

    LiH was used as inactive material to stimulate the reprocessing of lithium tritiate in molten chlorides. The electrochemical properties (diffusion coefficients, apparent standard potentials) were measured by means of transient electrochemical techniques (cyclic voltammetry and chronopotentiometry). At 425 ºC the diffusion coefficient and the apparent standard potential were 2.5 · 10-5 cm2 s-1 and -1.8 V vs. Ag/AgCl, respectively. For the process design the LiH solubility was measured by means of DTA to optimize the LiH concentration in the molten phase. In addition electrolysis tests were carried out at 460 ºC with current densities up to 1 A cm-2 over 24 h. These results show that LiH may be reprocessed in molten chlorides consisting in the production of hydrogen gas at the anode and molten metallic lithium at the cathode.

  1. Control of molten salt corrosion of fusion structural materials by metallic beryllium

    NASA Astrophysics Data System (ADS)

    Calderoni, P.; Sharpe, P.; Nishimura, H.; Terai, T.

    2009-04-01

    A series of tests have been performed between 2001 and 2006 at the Safety and Tritium Applied Research facility of the Idaho National Laboratory to demonstrate chemical compatibility between the molten salt flibe (2LiF + BeF 2 in moles) and fusion structural materials once suitable fluoride potential control methods are established. The tests adopted metallic beryllium contact as main fluoride potential control, and the results have been published in recent years. A further step was to expose two specimens of low activation ferritic/martensitic steel 9Cr-2W to static corrosion tests that include an active corrosion agent (hydrofluoric gas) in controlled conditions at 530 °C, and the results of the tests are presented in this paper. The results confirmed the expected correlation of the HF recovery with the concentration of metallic impurities dissolved in the salt because of specimen corrosion. The metals concentration dropped to levels close to the detectable limit when the beryllium rod was inserted and increased once the content of excess beryllium in the system had been consumed by HF reduction and specimen corrosion progressed. Metallographic analysis of the samples after 500 h exposure in reactive conditions showed evidence of the formation of unstable chromium oxide layers on the specimen's surface.

  2. Control of molten salt corrosion of fusion structural materials by metallic beryllium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    P. Calderoni; P. Sharpe; H. Nishimura

    2009-04-01

    A series of tests have been performed between 2001 and 2006 at the Safety and Tritium Applied Research facility of the Idaho National Laboratory to demonstrate chemical compatibility between the molten salt flibe (2LiF+BeF2 in moles) and fusion structural materials once suitable fluoride potential control methods are established. The tests adopted metallic beryllium contact as main fluoride potential control, and the results have been published in recent years. A further step was to expose two specimens of low activation ferritic/martensitic steel 9Cr-2W to static corrosion tests that include an active corrosion agent (hydrofluoric gas) in controlled conditions at 530 C,more » and the results of the tests are presented in this paper. The results confirmed the expected correlation of the HF recovery with the concentration of metallic impurities dissolved in the salt because of specimen corrosion. The metals concentration dropped to level close to the detectable limit when the beryllium rod was inserted and increased once the content of excess beryllium in the system had been consumed by HF reduction and specimens corrosion progressed. Metallographic analysis of the samples after 500 hours exposure in reactive conditions showed evidence of the formation of unstable chromium oxide layers on the specimens surface.« less

  3. Effect of Alkali Metal Cations on Slow Inactivation of Cardiac Na+ Channels

    PubMed Central

    Townsend, Claire; Horn, Richard

    1997-01-01

    Human heart Na+ channels were expressed transiently in both mammalian cells and Xenopus oocytes, and Na+ currents measured using 150 mM intracellular Na+. The kinetics of decaying outward Na+ current in response to 1-s depolarizations in the F1485Q mutant depends on the predominant cation in the extracellular solution, suggesting an effect on slow inactivation. The decay rate is lower for the alkali metal cations Li+, Na+, K+, Rb+, and Cs+ than for the organic cations Tris, tetramethylammonium, N-methylglucamine, and choline. In whole cell recordings, raising [Na+]o from 10 to 150 mM increases the rate of recovery from slow inactivation at −140 mV, decreases the rate of slow inactivation at relatively depolarized voltages, and shifts steady-state slow inactivation in a depolarized direction. Single channel recordings of F1485Q show a decrease in the number of blank (i.e., null) records when [Na+]o is increased. Significant clustering of blank records when depolarizing at a frequency of 0.5 Hz suggests that periods of inactivity represent the sojourn of a channel in a slow-inactivated state. Examination of the single channel kinetics at +60 mV during 90-ms depolarizations shows that neither open time, closed time, nor first latency is significantly affected by [Na+]o. However raising [Na+]o decreases the duration of the last closed interval terminated by the end of the depolarization, leading to an increased number of openings at the depolarized voltage. Analysis of single channel data indicates that at a depolarized voltage a single rate constant for entry into a slow-inactivated state is reduced in high [Na+]o, suggesting that the binding of an alkali metal cation, perhaps in the ion-conducting pore, inhibits the closing of the slow inactivation gate. PMID:9234168

  4. Metal Hydride and Alkali Halide Opacities in Extrasolar Giant Planets and Cool Stellar Atmospheres

    NASA Technical Reports Server (NTRS)

    Weck, Philippe F.; Stancil, Phillip C.; Kirby, Kate; Schweitzer, Andreas; Hauschildt, Peter H.

    2006-01-01

    The lack of accurate and complete molecular line and continuum opacity data has been a serious limitation to developing atmospheric models of cool stars and Extrasolar Giant Planets (EGPs). We report our recent calculations of molecular opacities resulting from the presence of metal hydrides and alkali halides. The resulting data have been included in the PHOENIX stellar atmosphere code (Hauschildt & Baron 1999). The new models, calculated using spherical geometry for all gravities considered, also incorporate our latest database of nearly 670 million molecular lines, and updated equations of state.

  5. Production of Titanium Metal by an Electrochemical Molten Salt Process

    NASA Astrophysics Data System (ADS)

    Fatollahi-Fard, Farzin

    Titanium production is a long and complicated process. What we often consider to be the standard method of primary titanium production (the Kroll process), involves many complex steps both before and after to make a useful product from titanium ore. Thus new methods of titanium production, especially electrochemical processes, which can utilize less-processed feedstocks have the potential to be both cheaper and less energy intensive than current titanium production processes. This project is investigating the use of lower-grade titanium ores with the electrochemical MER process for making titanium via a molten salt process. The experimental work carried out has investigated making the MER process feedstock (titanium oxycarbide) with natural titanium ores--such as rutile and ilmenite--and new ways of using the MER electrochemical reactor to "upgrade" titanium ores or the titanium oxycarbide feedstock. It is feasible to use the existing MER electrochemical reactor to both purify the titanium oxycarbide feedstock and produce titanium metal.

  6. Cathodes for molten-salt batteries

    NASA Technical Reports Server (NTRS)

    Argade, Shyam D.

    1993-01-01

    Viewgraphs of the discussion on cathodes for molten-salt batteries are presented. For the cathode reactions in molten-salt cells, chlorine-based and sulfur-based cathodes reactants have relatively high exchange current densities. Sulfur-based cathodes, metal sulfides, and disulfides have been extensively investigated. Primary thermal batteries of the Li-alloy/FeS2 variety have been available for a number of years. Chlorine based rechargable cathodes were investigated for the pulse power application. A brief introduction is followed by the experimental aspects of research, and the results obtained. Performance projections to the battery system level are discussed and the presentation is summarized with conclusions.

  7. Metal atomization spray nozzle

    DOEpatents

    Huxford, T.J.

    1993-11-16

    A spray nozzle for a magnetohydrodynamic atomization apparatus has a feed passage for molten metal and a pair of spray electrodes mounted in the feed passage. The electrodes, diverging surfaces which define a nozzle throat and diverge at an acute angle from the throat. Current passes through molten metal when fed through the throat which creates the Lorentz force necessary to provide atomization of the molten metal. 6 figures.

  8. Single ion dynamics in molten sodium bromide

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Alcaraz, O.; Trullas, J.; Demmel, F.

    We present a study on the single ion dynamics in the molten alkali halide NaBr. Quasielastic neutron scattering was employed to extract the self-diffusion coefficient of the sodium ions at three temperatures. Molecular dynamics simulations using rigid and polarizable ion models have been performed in parallel to extract the sodium and bromide single dynamics and ionic conductivities. Two methods have been employed to derive the ion diffusion, calculating the mean squared displacements and the velocity autocorrelation functions, as well as analysing the increase of the line widths of the self-dynamic structure factors. The sodium diffusion coefficients show a remarkable goodmore » agreement between experiment and simulation utilising the polarisable potential.« less

  9. Quantum State-Resolved Collision Dynamics of Nitric Oxide at Ionic Liquid and Molten Metal Surfaces

    NASA Astrophysics Data System (ADS)

    Zutz, Amelia Marie

    Detailed molecular scale interactions at the gas-liquid interface are explored with quantum state-to-state resolved scattering of a jet-cooled beam of NO(2pi1/2; N = 0) from ionic liquid and molten metal surfaces. The scattered distributions are probed via laser-induced fluorescence methods, which yield rotational and spin-orbit state populations that elucidate the dynamics of energy transfer at the gas-liquid interface. These collision dynamics are explored as a function of incident collision energy, surface temperature, scattering angle, and liquid identity, all of which are found to substantially affect the degree of rotational, electronic and vibrational excitation of NO via collisions at the liquid surface. Rotational distributions observed reveal two distinct scattering pathways, (i) molecules that trap, thermalize and eventually desorb from the surface (trapping-desorption, TD), and (ii) those that undergo prompt recoil (impulsive scattering, IS) prior to complete equilibration with the liquid surface. Thermally desorbing NO molecules are found to have rotational temperatures close to, but slightly cooler than the surface temperature, indicative of rotational dependent sticking probabilities on liquid surfaces. Nitric oxide is a radical with multiple low-lying electronic states that serves as an ideal candidate for exploring nonadiabatic state-changing collision dynamics at the gas-liquid interface, which induce significant excitation from ground (2pi1/2) to excited (2pi 3/2) spin-orbit states. Molecular beam scattering of supersonically cooled NO from hot molten metals (Ga and Au, Ts = 300 - 1400 K) is also explored, which provide preliminary evidence for vibrational excitation of NO mediated by thermally populated electron-hole pairs in the hot, conducting liquid metals. The results highlight the presence of electronically nonadiabatic effects and build toward a more complete characterization of energy transfer dynamics at gas-liquid interfaces.

  10. Carbonation of metal silicates for long-term CO.sub.2 sequestration

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Blencoe, James G.; Palmer, Donald A.; Anovitz, Lawrence M.

    In a preferred embodiment, the invention relates to a process of sequestering carbon dioxide. The process comprises the steps of: (a) reacting a metal silicate with a caustic alkali-metal hydroxide to produce a hydroxide of the metal formerly contained in the silicate; (b) reacting carbon dioxide with at least one of a caustic alkali-metal hydroxide and an alkali-metal silicate to produce at least one of an alkali-metal carbonate and an alkali-metal bicarbonate; and (c) reacting the metal hydroxide product of step (a) with at least one of the alkali-metal carbonate and the alkali-metal bicarbonate produced in step (b) to producemore » a carbonate of the metal formerly contained in the metal silicate of step (a).« less

  11. Carbonation of metal silicates for long-term CO.sub.2 sequestration

    DOEpatents

    Blencoe, James G [Harriman, TN; Palmer, Donald A [Oliver Springs, TN; Anovitz, Lawrence M [Knoxville, TN; Beard, James S [Martinsville, VA

    2012-02-14

    In a preferred embodiment, the invention relates to a process of sequestering carbon dioxide. The process comprises the steps of: (a) reacting a metal silicate with a caustic alkali-metal hydroxide to produce a hydroxide of the metal formerly contained in the silicate; (b) reacting carbon dioxide with at least one of a caustic alkali-metal hydroxide and an alkali-metal silicate to produce at least one of an alkali-metal carbonate and an alkali-metal bicarbonate; and (c) reacting the metal hydroxide product of step (a) with at least one of the alkali-metal carbonate and the alkali-metal bicarbonate produced in step (b) to produce a carbonate of the metal formerly contained in the metal silicate of step (a).

  12. The Au Cathode in the System Li2CO3-CO2-CO at 800 to 900 C

    NASA Technical Reports Server (NTRS)

    Hagedorn, Norman H.

    1991-01-01

    Gold is one of several metals being evaluated at NASA Lewis Research Center as positive electrode catalysts for an alkali metal/molten alkali metal carbonate/carbon dioxide electrochemical cell. Such a cell is proposed for CO2-rich planetary atmospheres such as those of Mars and Venus. Its application could be as a primary power supply, as a secondary power supply recharged either 'chemically' by replenishment of the alkali metal or electrochemically from a central station power source, or as a converter of carbon dioxide to oxygen via a complete electrochemical cycle. For the work being reported, lithium was assumed to be the alkali metal of choice for the negative electrode of the cell, and therefore molten lithium carbonate was the electrolyte used in the Au electrode experiments. Cathodic linear sweep voltammetry (LSV) was the primary analytical technique for evaluating the performance of the Au cathode. interest comprised the cell temperature and the total pressure and composition of the reactant gas. In the absence of operational difficulties, the effect of bubbling the reactant gas through the melt was also determined. On the basis of the variation of electrode performance with changes in these parameters, inferences have been made concerning the electrochemical and chemical processes at and near the electrode. The results of post-test micrographic analyses of the Au cathode are also presented. An attempt is then made to project from the experimental results to some relevant conclusions pertaining to a gold cathode in a practical alkali metal - carbon dioxide cell.

  13. Nickel-plating for active metal dissolution resistance in molten fluoride salts

    NASA Astrophysics Data System (ADS)

    Olson, Luke; Sridharan, Kumar; Anderson, Mark; Allen, Todd

    2011-04-01

    Ni electroplating of Incoloy-800H was investigated with the goal of mitigating Cr dissolution from this alloy into molten 46.5%LiF-11.5%NaF-42%KF eutectic salt, commonly referred to as FLiNaK. Tests were conducted in graphite crucibles at a molten salt temperature of 850 °C. The crucible material graphite accelerates the corrosion process due to the large activity difference between the graphite and the alloy. For the purposes of providing a baseline for this study, un-plated Incoloy-800H and a nearly pure Ni-alloy, Ni-201 were also tested. Results indicate that Ni-plating has the potential to significantly improve the corrosion resistance of Incoloy-800H in molten fluoride salts. Diffusion of Cr from the alloy through the Ni-plating does occur and if the Ni-plating is thin enough this Cr eventually dissolves into the molten salt. The post-corrosion test microstructure of the Ni-plating, particularly void formation was also observed to depend on the plating thickness. Diffusion anneals in a helium environment of Ni-plated Incoloy-800H and an Fe-Ni-Cr model alloy were also investigated to understand Cr diffusion through the Ni-plating. Further enhancements in the efficacy of the Ni-plating as a protective barrier against Cr dissolution from the alloy into molten fluoride salts can be achieved by thermally forming a Cr 2O 3 barrier film on the surface of the alloy prior to Ni electroplating.

  14. A novel molten-salt electrochemical cell for investigating the reduction of uranium dioxide to uranium metal by lithium using in situ synchrotron radiation

    PubMed Central

    Brown, Leon D.; Abdulaziz, Rema; Jervis, Rhodri; Bharath, Vidal; Mason, Thomas J.; Reinhard, Christina; Connor, Leigh D.; Inman, Douglas; Brett, Daniel J. L.; Shearing, Paul R.

    2017-01-01

    A novel electrochemical cell has been designed and built to allow for in situ energy-dispersive X-ray diffraction measurements to be made during reduction of UO2 to U metal in LiCl–KCl at 500°C. The electrochemical cell contains a recessed well at the bottom of the cell into which the working electrode sits, reducing the beam path for the X-rays through the molten-salt and maximizing the signal-to-noise ratio from the sample. Lithium metal was electrodeposited onto the UO2 working electrode by exposing the working electrode to more negative potentials than the Li deposition potential of the LiCl–KCl eutectic electrolyte. The Li metal acts as a reducing agent for the chemical reduction of UO2 to U, which appears to proceed to completion. All phases were fitted using Le Bail refinement. The cell is expected to be widely applicable to many studies involving molten-salt systems. PMID:28244437

  15. A novel molten-salt electrochemical cell for investigating the reduction of uranium dioxide to uranium metal by lithium using in situ synchrotron radiation.

    PubMed

    Brown, Leon D; Abdulaziz, Rema; Jervis, Rhodri; Bharath, Vidal; Mason, Thomas J; Atwood, Robert C; Reinhard, Christina; Connor, Leigh D; Inman, Douglas; Brett, Daniel J L; Shearing, Paul R

    2017-03-01

    A novel electrochemical cell has been designed and built to allow for in situ energy-dispersive X-ray diffraction measurements to be made during reduction of UO 2 to U metal in LiCl-KCl at 500°C. The electrochemical cell contains a recessed well at the bottom of the cell into which the working electrode sits, reducing the beam path for the X-rays through the molten-salt and maximizing the signal-to-noise ratio from the sample. Lithium metal was electrodeposited onto the UO 2 working electrode by exposing the working electrode to more negative potentials than the Li deposition potential of the LiCl-KCl eutectic electrolyte. The Li metal acts as a reducing agent for the chemical reduction of UO 2 to U, which appears to proceed to completion. All phases were fitted using Le Bail refinement. The cell is expected to be widely applicable to many studies involving molten-salt systems.

  16. Horizontal electromagnetic casting of thin metal sheets

    DOEpatents

    Hull, John R.; Lari, Robert J.; Praeg, Walter F.; Turner, Larry R.

    1987-01-01

    Thin metal sheets are cast by magnetically suspending molten metal deposited within a ferromagnetic yoke and between AC conducting coils and linearly displacing the magnetically levitated liquid metal while it is being cooled to form a solid metal sheet. Magnetic flux increases as the molten metal sheet moves downward and decreases as the molten metal sheet moves upward to stabilize the sheet and maintain it in equilibrium as it is linearly displaced and solidified by cooling gases. A conducting shield is electrically coupled to the molten metal sheet by means of either metal sheet engaging rollers or brushes on the solidified metal, and by means of an electrode in the vessel containing the molten metal thereby providing a return path for the eddy currents induced in the metal sheet by the AC coil generated magnetic flux. Variation in the geometry of the conducting shield allows the magnetic flux between the metal sheet and the conducting shield to be varied and the thickness in surface quality of the metal sheet to be controlled. Side guards provide lateral containment for the molten metal sheet and stabilize and shape the magnetic field while a leader sheet having electromagnetic characteristics similar to those of the metal sheet is used to start the casting process and precedes the molten metal sheet through the magnet and forms a continuous sheet therewith. The magnet may be either U-shaped with a single racetrack coil or may be rectangular with a pair of facing bedstead coils.

  17. Horizontal electromagnetic casting of thin metal sheets

    DOEpatents

    Hull, John R.; Lari, Robert J.; Praeg, Walter F.; Turner, Larry R.

    1988-01-01

    Thin metal sheets are cast by magnetically suspending molten metal deposited within a ferromagnetic yoke and between AC conducting coils and linearly displacing the magnetically levitated liquid metal while it is being cooled to form a solid metal sheet. Magnetic flux increases as the molten metal sheet moves downward and decreases as the molten metal sheet moves upward to stabilize the sheet and maintain it in equilibrium as it is linearly displaced and solidified by cooling gases. A conducting shield is electrically coupled to the molten metal sheet by means of either metal sheet engaging rollers or brushes on the solidified metal, and by means of an electrode in the vessel containing the molten metal thereby providing a return path for the eddy currents induced in the metal sheet by the AC coil generated magnetic flux. Variation in the geometry of the conducting shield allows the magnetic flux between the metal sheet and the conducting shield to be varied and the thickness in surface quality of the metal sheet to be controlled. Side guards provide lateral containment for the molten metal sheet and stabilize and shape the magnetic field while a leader sheet having electromagnetic characteristics similar to those of the metal sheet is used to start the casting process and precedes the molten metal sheet through the magnet and forms a continuous sheet therewith. The magnet may be either U-shaped with a single racetrack coil or may be rectangular with a pair of facing bedstead coils.

  18. SEPARATION OF PROTACTINIUM FROM MOLTEN SALT REACTOR FUEL COMPOSITIONS

    DOEpatents

    Shaffer, J.H.; Strain, J.E.; Cuneo, D.R.; Kelly, M.J.

    1963-11-12

    A method for selectively precipitating protactinium from a neutron- irradiated fused fluoride salt composition comprising at least one metal fluoride selected from the group consisting of an alkali metal fluoride and an alkaline earth metal fluoride containing dissolved thorium-232 values is presented. An inorganic metal oxide corresponding to any of the metal fluorides of the composition is also added. (AEC)

  19. Presence of Li clusters in molten LiCl-Li

    DOE PAGES

    Merwin, Augustus; Phillips, William C.; Williamson, Mark A.; ...

    2016-05-05

    Molten mixtures of lithium chloride and metallic lithium are of significant interest in various metal oxide reduction processes. These solutions have been reported to exhibit seemingly anomalous physical characteristics that lack a comprehensive explanation. ln the current work, the physical chemistry of molten solutions of lithium chloride and metallic lithium, with and without lithium oxide, was investigated using in situ Raman spectroscopy. The Raman spectra obtained from these solutions were in agreement with the previously reported spectrum of the lithium cluster, Li 8. Furthermore, this observation is indicative of a nanofluid type colloidal suspension of Li 8, in a moltenmore » salt matrix. It is suggested that the formation and suspension of lithium clusters in lithium chloride is the cause of various phenomena exhibited by these solutions that were previously unexplainable.« less

  20. Doppler-free satellites of resonances of electromagnetically induced transparency and absorption on the D 2 lines of alkali metals

    NASA Astrophysics Data System (ADS)

    Sargsyan, A.; Sarkisyan, D.; Staedter, D.; Akulshin, A. M.

    2006-11-01

    The peculiarities of intra-Doppler structures that are observed in the atomic absorption spectrum of alkali metals with the help of two independent lasers have been studied. These structures accompany ultranarrow coherent resonances of electromagnetically induced transparency and absorption. With the D 2 line of rubidium taken as an example, it is shown that, in the scheme of unidirectional waves, the maximum number of satellite resonances caused by optical pumping selective with respect to the atomic velocity is equal to seven, while only six resonances are observed in the traditional scheme of saturated absorption with counterpropagating waves of the same frequency. The spectral position of the resonances and their polarity depend on the frequency of the saturating radiation, while their number and relative amplitude depend also on the experimental geometry. These features are of general character and should show themselves in the absorption spectrum on the D 2 lines of all alkali metals. An explanation of these features is given. The calculated spectral separations between the resonances are compared to the experimental ones, and their possible application is discussed.

  1. Molten metal burns: further evidence of industrial foundries' failure to comply with Occupational Safety and Health Administration regulations.

    PubMed

    Faulkner, B C; Drake, D B; Gear, A J; Watkins, F H; Edlich, R F

    1997-01-01

    The purpose of this report is to describe another case of a molten metal burn to the foot of a foundry worker. The foundry in which he worked failed to comply with Occupational Safety and Health Administration regulations with regard to protective apparel. This injury could have been prevented with annual, unscheduled inspections by the Occupational Safety and Health Administration and with enforcement of additional regulations regarding protective apparel.

  2. Anode composite for molten carbonate fuel cell

    DOEpatents

    Iacovangelo, Charles D.; Zarnoch, Kenneth P.

    1983-01-01

    An anode composite useful for a molten carbonate fuel cell comprised of a porous sintered metallic anode component having a porous bubble pressure barrier integrally sintered to one face thereof, said barrier being comprised of metal coated ceramic particles sintered together and to said anode by means of said metal coating, said metal coating enveloping said ceramic particle and being selected from the group consisting of nickel, copper and alloys thereof, the median pore size of the barrier being significantly smaller than that of the anode.

  3. Deliberate and Accidental Gas-Phase Alkali Doping of Chalcogenide Semiconductors: Cu(In,Ga)Se2

    PubMed Central

    Colombara, Diego; Berner, Ulrich; Ciccioli, Andrea; Malaquias, João C.; Bertram, Tobias; Crossay, Alexandre; Schöneich, Michael; Meadows, Helene J.; Regesch, David; Delsante, Simona; Gigli, Guido; Valle, Nathalie; Guillot, Jérome; El Adib, Brahime; Grysan, Patrick; Dale, Phillip J.

    2017-01-01

    Alkali metal doping is essential to achieve highly efficient energy conversion in Cu(In,Ga)Se2 (CIGSe) solar cells. Doping is normally achieved through solid state reactions, but recent observations of gas-phase alkali transport in the kesterite sulfide (Cu2ZnSnS4) system (re)open the way to a novel gas-phase doping strategy. However, the current understanding of gas-phase alkali transport is very limited. This work (i) shows that CIGSe device efficiency can be improved from 2% to 8% by gas-phase sodium incorporation alone, (ii) identifies the most likely routes for gas-phase alkali transport based on mass spectrometric studies, (iii) provides thermochemical computations to rationalize the observations and (iv) critically discusses the subject literature with the aim to better understand the chemical basis of the phenomenon. These results suggest that accidental alkali metal doping occurs all the time, that a controlled vapor pressure of alkali metal could be applied during growth to dope the semiconductor, and that it may have to be accounted for during the currently used solid state doping routes. It is concluded that alkali gas-phase transport occurs through a plurality of routes and cannot be attributed to one single source. PMID:28233864

  4. Deliberate and Accidental Gas-Phase Alkali Doping of Chalcogenide Semiconductors: Cu(In,Ga)Se2.

    PubMed

    Colombara, Diego; Berner, Ulrich; Ciccioli, Andrea; Malaquias, João C; Bertram, Tobias; Crossay, Alexandre; Schöneich, Michael; Meadows, Helene J; Regesch, David; Delsante, Simona; Gigli, Guido; Valle, Nathalie; Guillot, Jérome; El Adib, Brahime; Grysan, Patrick; Dale, Phillip J

    2017-02-24

    Alkali metal doping is essential to achieve highly efficient energy conversion in Cu(In,Ga)Se 2 (CIGSe) solar cells. Doping is normally achieved through solid state reactions, but recent observations of gas-phase alkali transport in the kesterite sulfide (Cu 2 ZnSnS 4 ) system (re)open the way to a novel gas-phase doping strategy. However, the current understanding of gas-phase alkali transport is very limited. This work (i) shows that CIGSe device efficiency can be improved from 2% to 8% by gas-phase sodium incorporation alone, (ii) identifies the most likely routes for gas-phase alkali transport based on mass spectrometric studies, (iii) provides thermochemical computations to rationalize the observations and (iv) critically discusses the subject literature with the aim to better understand the chemical basis of the phenomenon. These results suggest that accidental alkali metal doping occurs all the time, that a controlled vapor pressure of alkali metal could be applied during growth to dope the semiconductor, and that it may have to be accounted for during the currently used solid state doping routes. It is concluded that alkali gas-phase transport occurs through a plurality of routes and cannot be attributed to one single source.

  5. Production of Oxygen from Lunar Regolith using Molten Oxide Electrolysis

    NASA Technical Reports Server (NTRS)

    Sibille, Laurent; Sadoway, Donald R.; Sirk, Aislinn; Tripathy, Prabhat; Melendez, Orlando; Standish, Evan; Dominquez, Jesus A.; Stefanescu, Doru M.; Curreri, Peter A.; Poizeau, Sophie

    2009-01-01

    This slide presentation reviews the possible use of molten oxide electrolysis to extract oxygen from the Lunar Regolith. The presentation asserts that molten regolith electrolysis has advanced to be a useful method for production of oxygen and metals in situ on the Moon. The work has demonstrated an 8 hour batch of electrolysis at 5 amps using Iridium inert anodes.

  6. Electrochemical synthesis of superconductive MgB 2 from molten salts

    NASA Astrophysics Data System (ADS)

    Yoshii, Kenji; Abe, Hideki

    2003-05-01

    We have found that superconductive MgB2 can be electrochemically synthesized from molten salts. The electrolysis was performed in an Ar flow at 600 °C on fused mixtures composed of MgCl2, MgB2O4, Na2B2O4 and alkali halides such as KCl, NaCl, and LiCl. Superconductivity was observed for a wide variety of electrolytes. It was also found that the magnetic and electrical transport properties are the most improved for samples prepared from MgCl2-NaCl-KCl-MgB2O4 electrolytes.

  7. Coverage dependent work function of graphene on a Cu(111) substrate with intercalated alkali metals

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cook, Brandon G.; Russakoff, Arthur; Varga, Kalman

    2015-05-26

    Using first-principles calculations, it is shown that the work function of graphene on copper can be adjusted by varying the concentration of intercalated alkali metals. Using density functional theory, we calculate the modulation of work function when Li, Na, or K are intercalated between graphene and a Cu(111) surface. Furthermore, the physical origins of the change in work function are explained in terms of phenomenological models accounting for the formation and depolarization of interfacial dipoles and the shift in the Fermi-level induced via charge transfer.

  8. Correction: A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide.

    PubMed

    Ng, Chee Koon; Wu, Jie; Hor, T S Andy; Luo, He-Kuan

    2016-12-22

    Correction for 'A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide' by Chee Koon Ng et al., Chem. Commun., 2016, 52, 11842-11845.

  9. Method of coating metal surfaces to form protective metal coating thereon

    DOEpatents

    Krikorian, Oscar H.; Curtis, Paul G.

    1992-01-01

    A process is disclosed for forming a protective metal coating on a metal surface using a flux consisting of an alkali metal fluoride, an alkaline earth metal fluoride, an alkali metal fluoaluminate, an alkali metal fluosilicate, and mixtures thereof. The flux, in particulate form, is mixed with particles of a metal coating material which may comprise aluminum, chromium, mixtures thereof, and alloys containing at least 50 wt. % aluminum and the particulate mixture is applied to the metal surface in a single step, followed by heating the coated metal surface to a temperature sufficient to cause the metal coating material to react with the metal surface to form a protective reaction product in the form of a metal coating bonded to the metal surface. The metal surface which reacts with the metal coating material to form the protective coating may comprise Fe, Co, Ni, Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Hf, Ta, W, Re and alloys thereof.

  10. Method of coating metal surfaces to form protective metal coating thereon

    DOEpatents

    Krikorian, O.H.; Curtis, P.G.

    1992-03-31

    A process is disclosed for forming a protective metal coating on a metal surface using a flux consisting of an alkali metal fluoride, an alkaline earth metal fluoride, an alkali metal fluoaluminate, an alkali metal fluosilicate, and mixtures thereof. The flux, in particulate form, is mixed with particles of a metal coating material which may comprise aluminum, chromium, mixtures thereof, and alloys containing at least 50 wt. % aluminum and the particulate mixture is applied to the metal surface in a single step, followed by heating the coated metal surface to a temperature sufficient to cause the metal coating material to react with the metal surface to form a protective reaction product in the form of a metal coating bonded to the metal surface. The metal surface which reacts with the metal coating material to form the protective coating may comprise Fe, Co, Ni, Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Hf, Ta, W, Re and alloys thereof. 1 figure.

  11. High-temperature, high-pressure hydrothermal synthesis, characterization, and structural relationships of mixed-alkali metals uranyl silicates

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, Yi-Hsin; Liu, Hsin-Kuan; Chang, Wen-Jung

    2016-04-15

    Three mixed-alkali metals uranyl silicates, Na{sub 3}K{sub 3}[(UO{sub 2}){sub 3}(Si{sub 2}O{sub 7}){sub 2}]·2H{sub 2}O (1), Na{sub 3}Rb{sub 3}[(UO{sub 2}){sub 3}(Si{sub 2}O{sub 7}){sub 2}] (2), and Na{sub 6}Rb{sub 4}[(UO{sub 2}){sub 4}Si{sub 12}O{sub 33}] (3), have been synthesized by high-temperature, high-pressure hydrothermal reactions at 550 °C and 1440 bar, and characterized by single-crystal X-ray diffraction, photoluminescence, and thermogravimetric analysis. Compound 1 and 2 are isostructural and contain layers of uranyl disilicate. The smaller cation, Na{sup +}, is located in the intralayer channels, whereas the larger cations, K{sup +} and Rb{sup +}, and water molecule are located in the interlayer region. The absencemore » of lattice water in 2 can be understood according to the valence-matching principle. The structure is related to that of a previously reported mixed-valence uranium(V,VI) silicate. Compound 3 adopts a 3D framework structure and contains a unique unbranched dreier fourfold silicate chain with the structural formula {uB,4"1_∞}[{sup 3}Si{sub 12}O{sub 33}] formed of Q{sup 2}, Q{sup 3}, and Q{sup 4} Si. The connectivity of the Si atoms in the Si{sub 12}O{sub 33}{sup 18−} anion can be interpreted on the basis of Zintl–Klemm concept. Crystal data for compound 1: triclinic, P-1, a=5.7981(2) Å, b=7.5875(3) Å, c=12.8068(5) Å, α=103.593(2)°, β=102.879(2)°, γ=90.064(2)°, V=533.00(3) Å{sup 3}, Z=1, R1=0.0278; compound 2: triclinic, P-1, a=5.7993(3) Å, b=7.5745(3) Å, c=12.9369(6) Å, α=78.265(2)°, β=79.137(2)°, γ=89.936(2)°, V=546.02(4) Å{sup 3}, Z=1, R1=0.0287; compound 3: monoclinic, C2/m, a=23.748(1) Å, b=7.3301(3) Å, c=15.2556(7) Å, β=129.116(2)°, V=2060.4(2) Å{sup 3}, Z=2, R1=0.0304. - Graphical abstract: Three mixed-alkali metals uranyl silicates were synthesized under hydrothermal conditions at 550 °C and 1400 bar and structurally characterized by single-crystal X-ray diffraction. Two of them have a layer

  12. Corrosion testing of zirconia, beryllia and magnesia ceramics in molten alkali metal carbonates at 900 °C

    NASA Astrophysics Data System (ADS)

    Kaplan, Valery; Bendikov, Tatyana; Feldman, Yishay; Gartsman, Konstantin; Wachtel, Ellen; Lubomirsky, Igor

    2016-01-01

    An electrochemical cell containing molten Li2CO3-Li2O at 900 °C has been proposed for the conversion of the greenhouse gas CO2 to CO for chemical energy storage. In the current work, we have examined the corrosion resistance of zirconia, beryllia and magnesia ceramics at 900 °C in the Li2CO3-Li2O and Li-Na-K carbonate eutectic mixtures to identify suitable electrically insulating materials. Conclusions regarding material stability were based on elemental analysis of the melt, primarily via X-ray photoelectron spectroscopy, a particularly sensitive technique. It was found that magnesia is completely stable for at least 33 h in a Li2CO3-Li2O melt, while a combined lithium titanate/lithium zirconate layer forms on the zirconia ceramic as detected by XRD. Under the same melt conditions, beryllia shows considerable leaching into solution. In a Li-Na-K carbonate eutectic mixture containing 10.2 mol% oxide at 900 °C under standard atmospheric conditions, magnesia showed no signs of degradation. Stabilization of the zirconia content of the eutectic mixture at 0.01-0.02 at% after 2 h is explained by the formation of a lithium zirconate coating on the ceramic. On the basis of these results, we conclude that only magnesia can be satisfactorily used as an insulating material in electrolysis cells containing Li2CO3-Li2O melts.

  13. The Study of Anti-/Pro-Oxidant, Lipophilic, Microbial and Spectroscopic Properties of New Alkali Metal Salts of 5-O-Caffeoylquinic Acid

    PubMed Central

    Kalinowska, Monika; Bajko, Ewelina; Matejczyk, Marzena; Kaczyński, Piotr; Łozowicka, Bożena; Lewandowski, Włodzimierz

    2018-01-01

    Lithium, sodium, potassium, rubidium and caesium salts of 5-O-caffeoylquinic acid (chlorogenic acid, 5-CQA) were synthesized and described by FT-IR (infrared spectroscopy), FT-Raman (Raman spectroscopy), UV (UV absorption spectroscopy), 1H (400.15 MHz), 13C (100.63 MHz) NMR (nuclear magnetic resonance spectroscopy). The quantum–chemical calculations at the B3LYP/6-311++G** level were done in order to obtain the optimal structures, IR spectra, NBO (natural bond orbital) atomic charges, HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) orbitals and chemical reactivity parameters for 5-CQA and Li, Na and K 5-CQAs (chlorogenates). The DPPH (α, α-diphenyl-β-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) assays were used for the preliminary estimation of the antioxidant properties of alkali metal chlorogenates and chlorogenic acid. In the DPPH assay the EC50 parameter were equal to 7.39 μM for 5-CQA and was in the range of 4.50–5.89 μM for salts. The FRAP values for two different concentrations (5 and 2.5 μM) of the studied compounds were respectively 114.22 and 72.53 μM Fe2+ for 5-CQA, whereas for salts they were 106.92–141.13 and 78.93–132.00 μM Fe2+. The 5-CQA and its alkali metal salts possess higher antioxidant properties than commonly applied antioxidants (BHA, BHT, l-ascorbic acid). The pro-oxidant action of these compounds on trolox oxidation was studied in the range of their concentration 0.05–0.35 μM. The lipophilicity (logkw) of chlorogenates and chlorogenic acid was determined by RP-HPLC (reverse phase—high performance liquid chromatography) using five different columns (C8, PHE (phenyl), CN (cyano), C18, IAM (immobilized artificial membrane)). The compounds were screened for their in vitro antibacterial activity against E. coli, Bacillus sp., Staphylococcus sp., Streptococcus pyogenes and antifungal activity against Candida sp. The 5-CQA possessed lower antibacterial (minimal

  14. Materials Testing for an Accelerator-Driven Subcritical Molten Salt Fission System: A look at the Materials Science of Molten Salt Corrosion

    NASA Astrophysics Data System (ADS)

    Sooby, Elizabeth; Balachandran, Shreyas; Foley, David; Hartwig, Karl; McIntyre, Peter; Phongikaroon, Supathorn; Pogue, Nathaniel; Simpson, Michael; Tripathy, Prabhat

    2011-10-01

    For an accelerator-driven subcritical molten salt fission core to survive its 50+ year fuel life, the primary vessel, heat exchanger, and various internal components must be made of materials that resist corrosion and radiation damage in a high-temperature environment, (500-800 C). An experimental study of the corrosion behavior of candidate metals in contact with molten salt is being conducted at the Center for Advanced Energy Studies. Initial experiments have been run on Nb, Ta, Ni, two zirconium alloys, Hastelloy-N, and a series of steel alloys to form a base line for corrosion in both chloride and bromide salt. Metal coupons were immersed in LiCl-KCl or LiBr-KBr at 700 C in an inert-atmosphere. Salt samples were extracted on a time schedule over a 24-hr period. The samples were analyzed using inductively coupled plasma-mass spectrometry to determine concentrations of metals from corrosion. Preliminary results will be presented.

  15. Relationship between spatter formation and dynamic molten pool during high-power deep-penetration laser welding

    NASA Astrophysics Data System (ADS)

    Li, Shichun; Chen, Genyu; Katayama, Seiji; Zhang, Yi

    2014-06-01

    The spatter and the molten pool behavior, which were the important phenomena concerned with the welding quality, were observed and studied by using the high-speed camera and the X-ray transmission imaging system during laser welding under different welding parameters. The formation mechanism of spatter and the corresponding relationships between the spatter and molten pool behavior were investigated. The increase of laser power could cause more intense evaporation and lead to more spatter. When the focal position of laser beam was changed, different forms of spatter were generated, as well as the flow trends of molten metal on the front keyhole wall and at the rear molten pool were changed. The results revealed that the behavior of molten pool, which could be affected by the absorbed energy distribution in the keyhole, was the key factor to determine the spatter formation during laser welding. The relatively sound weld seam could be obtained during laser welding with the focal position located inside the metal.

  16. Rotating cathode device for molten salt bath

    NASA Astrophysics Data System (ADS)

    1983-11-01

    The invention relates to a rotating cathode device for molten salt baths used to prepare metallic titanium or aluminum and the like by electrolysis of molten salts. The rotating cathode device is described. It is a cyclindrical cathode mounted on a rotating spindle, made of a lightweight material and mounted in such a way as to avoid thermal strain between the rotational shaft and the cylindrical cathode. At least one of the upper and lower ends of the cylindrical cathode are closed by a cap and a seal consisting of an inorganic fiber composite in the area between the cap and the cathode.

  17. Development of High-Temperature Transport Technologies of Molten Salt Slurry in Pyrometallurgical Reprocessing

    NASA Astrophysics Data System (ADS)

    Hijikata, Takatoshi; Koyama, Tadafumi

    Pyrometallurgical-reprocessing is one of the most promising technologies for advanced fuel cycle with favorable economic potential and intrinsic proliferation resistance. The development of transport technology for molten salt is a key issue in the industrialization of pyro-reprocessing. As for pure molten LiCl-KCl eutectic salt at approximately 773 K, we have already reported the successful results of transport using gravity and a centrifugal pump. However, molten salt in an electrorefiner mixes with insoluble fines when spent fuel is dissolved in porous anode basket. The insoluble consists of noble metal fission products, such as Pd, Ru, Mo, and Zr. There have been very few transport studies of a molten salt slurry (metal fines-molten salt mixture). Hence, transport experiments on a molten salt slurry were carried out to investigate the behavior of the slurry in a tube. The apparatus used in the transport experiments on the molten salt slurry consisted of a supply tank, a 10° inclined transport tube (10 mm inner diameter), a valve, a filter, and a recovery tank. Stainless steel (SS) fines with diameters from 53 to 415 μm were used. To disperse these fines homogenously, the molten salt and fines were stirred in the supply tank by an impeller at speeds from 1200 to 2100 rpm. The molten salt slurry containing 0.04 to 0.4 vol.% SS fines was transported from the supply tank to the recovery tank through the transportation tube. In the recovery tank, the fines were separated from the molten salt by the filter to measure the transport behavior of molten salt and SS fines. When the velocity of the slurry was 0.02 m/s, only 1% of the fines were transported to the recovery tank. On the other hand, most of the fines were transported when the velocity of the slurry was more than 0.8 m/s. Consequently, the molten salt slurry can be transported when the velocity is more than 0.8 m/s.

  18. Density functional theory study of oxygen migration in molten carbonate

    NASA Astrophysics Data System (ADS)

    Lei, Xueling; Haines, Kahla; Huang, Kevin; Qin, Changyong

    2016-02-01

    The process of oxygen migration in alkali molten carbonate salts has been examined using density functional theory method. All geometries were optimized at the B3LYP/6-31G(d) level, while single point energy corrections were performed using MP4 and CCSD(T). At TS, a O-O-O linkage is formed and O-O bond forming and breaking is concerted. A cooperative ;cogwheel; mechanism as described in the equation of CO42- + CO32- →CO32- ⋯O ⋯CO32- →CO32- + CO42- is involved. The energy barrier is calculated to be 103.0, 136.3 and 127.9 kJ/mol through an intra-carbonate pathway in lithium, sodium and potassium carbonate, respectively. The reliability and accuracy of B3LYP/6-31G(d) were confirmed by CCSD(T). The calculated low values of activation energy indicate that the oxygen transfer in molten carbonate salts is fairly easy. In addition, it is found that lithium carbonate is not only a favorable molten carbonate salt for better cathode kinetics, but also it is widely used for reducing the melting point of Li/Na and Li/K eutectic MC mixtures. The current results imply that the process of oxygen reduction in MC modified cathodes is facilitated by the presence of MC, resulting in an enhancement of cell performance at low operating temperatures.

  19. Sidewall containment of liquid metal with vertical alternating magnetic fields

    DOEpatents

    Lari, Robert J.; Praeg, Walter F.; Turner, Larry R.; Battles, James E.; Hull, John R.; Rote, Donald M.

    1990-01-01

    An apparatus for containing molten metal using a magnet producing vertical alternating magnetic field positioned adjacent the area in which the molten metal is to be confined. This invention can be adapted particularly to the casting of metal between counter-rotating rollers with the vertical alternating magnetic field used to confine the molten metal at the edges of the rollers. Alternately, the vertical alternating magnetic field can be used as a flow regulator in casting molten metal from an opening in a channel.

  20. Calorimetric Study of Alkali Metal Ion (K +, Na +, Li +) Exchange in a Clay-Like MXene

    DOE PAGES

    Sharma, Geetu; Muthuswamy, Elayaraja; Naguib, Michael; ...

    2017-06-21

    Intercalation of ions in layered materials has been explored to improve the rate capability in Li-ion batteries and supercapacitors. This work investigates the energetics of alkali ion exchange in a clay-like MXene, Ti 3C 2T x, where T x stands for anionic surface moieties, by immersion calorimetry in aqueous solutions. The measured immersion enthalpies of clay-like Ti 3C 2T x, ΔH imm, at 25 °C in 1 M KCl, 1 M NaCl, 1 M LiCl, and nanopure water are -9.19 (±0.56), -5.90 (±0.31), -1.31 (±0.20), and -1.29 (±0.13) kJ/mol of MXene, respectively. Inductively coupled plasma mass spectrometry is used tomore » obtain the concentrations of alkali ions in the solid and aqueous phases. Using these concentrations, the enthalpies of exchange of alkali metal ions (Li+, Na+, and K+) are calculated; ΔHex in 1 M KCl, 1 M NaCl, 1 M LiCl, and nanopure water are -9.3 (±2.2), 21.0 (±0.9), -1.3 (±0.2), and 302.4 (±0.6) kJ/mol of MXene, respectively. Both immersion and exchange enthalpies are most exothermic for potassium. This suggests that K+ ions interact more strongly with anions present in the interlayers of this MXene than Na + and Li + ions. Water vapor adsorption calorimetry indicates very weak interaction of water with the MXene, while immersion calorimetry suggests a weakly hydrophilic nature of the MXene surface.« less

  1. Calorimetric Study of Alkali Metal Ion (K +, Na +, Li +) Exchange in a Clay-Like MXene

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sharma, Geetu; Muthuswamy, Elayaraja; Naguib, Michael

    Intercalation of ions in layered materials has been explored to improve the rate capability in Li-ion batteries and supercapacitors. This work investigates the energetics of alkali ion exchange in a clay-like MXene, Ti 3C 2T x, where T x stands for anionic surface moieties, by immersion calorimetry in aqueous solutions. The measured immersion enthalpies of clay-like Ti 3C 2T x, ΔH imm, at 25 °C in 1 M KCl, 1 M NaCl, 1 M LiCl, and nanopure water are -9.19 (±0.56), -5.90 (±0.31), -1.31 (±0.20), and -1.29 (±0.13) kJ/mol of MXene, respectively. Inductively coupled plasma mass spectrometry is used tomore » obtain the concentrations of alkali ions in the solid and aqueous phases. Using these concentrations, the enthalpies of exchange of alkali metal ions (Li+, Na+, and K+) are calculated; ΔHex in 1 M KCl, 1 M NaCl, 1 M LiCl, and nanopure water are -9.3 (±2.2), 21.0 (±0.9), -1.3 (±0.2), and 302.4 (±0.6) kJ/mol of MXene, respectively. Both immersion and exchange enthalpies are most exothermic for potassium. This suggests that K+ ions interact more strongly with anions present in the interlayers of this MXene than Na + and Li + ions. Water vapor adsorption calorimetry indicates very weak interaction of water with the MXene, while immersion calorimetry suggests a weakly hydrophilic nature of the MXene surface.« less

  2. Facile preparation of highly pure KF-ZrF4 molten salt

    NASA Astrophysics Data System (ADS)

    Zong, Guoqiang; Cui, Zhen-Hua; Zhang, Zhi-Bing; Zhang, Long; Xiao, Ji-Chang

    2018-03-01

    The preparation of highly pure KF-ZrF4 (FKZr) molten salt, a potential secondary coolant in molten salt reactors, was realized simply by heating a mixture of (NH4)2ZrF6 and KF. X-ray diffraction analysis indicated that the FKZr molten salt was mainly composed of KZrF5 and K2ZrF6. The melting point of the prepared FKZr molten salt was 420-422 °C under these conditions. The contents of all metal impurities were lower than 20 ppm, and the content of oxygen was lower than 400 ppm. This one-step protocol avoids the need for a tedious procedure to prepare ZrF4 and for an additional purification process to remove oxide impurities, and is therefore a convenient, efficient and economic preparation method for high-purity FKZr molten salt.

  3. Gasification of black liquor

    DOEpatents

    Kohl, A.L.

    1987-07-28

    A concentrated aqueous black liquor containing carbonaceous material and alkali metal sulfur compounds is treated in a gasifier vessel containing a relatively shallow molten salt pool at its bottom to form a combustible gas and a sulfide-rich melt. The gasifier vessel, which is preferably pressurized, has a black liquor drying zone at its upper part, a black liquor solids gasification zone located below the drying zone, and a molten salt sulfur reduction zone which comprises the molten salt pool. A first portion of an oxygen-containing gas is introduced into the gas space in the gasification zone immediately above the molten salt pool. The remainder of the oxygen-containing gas is introduced into the molten salt pool in an amount sufficient to cause gasification of carbonaceous material entering the pool from the gasification zone but not sufficient to create oxidizing conditions in the pool. The total amount of the oxygen-containing gas introduced both above the pool and into the pool constitutes between 25 and 55% of the amount required for complete combustion of the black liquor feed. A combustible gas is withdrawn from an upper portion of the drying zone, and a melt in which the sulfur content is predominantly in the form of alkali metal sulfide is withdrawn from the molten salt sulfur reduction zone. 2 figs.

  4. Gasification of black liquor

    DOEpatents

    Kohl, Arthur L.

    1987-07-28

    A concentrated aqueous black liquor containing carbonaceous material and alkali metal sulfur compounds is treated in a gasifier vessel containing a relatively shallow molten salt pool at its bottom to form a combustible gas and a sulfide-rich melt. The gasifier vessel, which is preferably pressurized, has a black liquor drying zone at its upper part, a black liquor solids gasification zone located below the drying zone, and a molten salt sulfur reduction zone which comprises the molten salt pool. A first portion of an oxygen-containing gas is introduced into the gas space in the gasification zone immediatley above the molten salt pool. The remainder of the oxygen-containing gas is introduced into the molten salt pool in an amount sufficient to cause gasification of carbonaceous material entering the pool from the gasification zone but not sufficient to create oxidizing conditions in the pool. The total amount of the oxygen-containing gas introduced both above the pool and into the pool constitutes between 25 and 55% of the amount required for complete combustion of the black liquor feed. A combustible gas is withdrawn from an upper portion of the drying zone, and a melt in which the sulfur content is predominantly in the form of alkali metal sulfide is withdrawn from the molten salt sulfur reduction zone.

  5. Molten salt applications in materials processing

    NASA Astrophysics Data System (ADS)

    Mishra, Brajendra; Olson, David L.

    2005-02-01

    The science of molten salt electrochemistry for electrowinning of reactive metals, such as calcium, and its in situ application in pyro-reduction has been described. Calcium electrowinning has been performed in a 5 10 wt% calcium oxide calcium chloride molten salt by the electrolytic dissociation of calcium oxide. This electrolysis requires the use of a porous ceramic sheath around the anode to keep the cathodically deposited calcium and the anodic gases separate. Stainless steel cathode and graphite anode have been used in the temperature range of 850 950 °C. This salt mixture is produced as a result of the direct oxide reduction (DOR) of reactive metal oxides by calcium in a calcium chloride bath. The primary purpose of this process is to recover the expensive calcium reductant and to recycle calcium chloride. Experimental data have been included to justify the suitability as well as limitations of the electrowinning process. Transport of oxygen ions through the sheath is found to be the rate controlling step. Under the constraints of the reactor design, a calcium recovery rate of approx. 150 g/h was achieved. Feasibility of a process to produce metals by pyrometallurgical reduction, using the calcium reductant produced electrolytically within the same reactor, has been shown in a hybrid process. Several processes are currently under investigation to use this electrowon calcium for in situ reduction of metal oxides.

  6. Determination and evaluation of the thermophysical properties of an alkali carbonate eutectic molten salt.

    PubMed

    An, Xuehui; Cheng, Jinhui; Zhang, Peng; Tang, Zhongfeng; Wang, Jianqiang

    2016-08-15

    The thermal physical properties of Li2CO3-Na2CO3-K2CO3 eutectic molten salt were comprehensively investigated. It was found that the liquid salt can remain stable up to 658 °C (the onset temperature of decomposition) by thermal analysis, and so the investigations on its thermal physical parameters were undertaken from room temperature to 658 °C. The density was determined using a self-developed device, with an uncertainty of ±0.00712 g cm(-3). A cooling curve was obtained from the instrument, giving the liquidus temperature. For the first time, we report the obtainment of the thermal diffusivity using a laser flash method based on a special crucible design and establishment of a specific sample preparation method. Furthermore, the specific heat capacity was also obtained by use of DSC, and combined with thermal diffusivity and density, was used to calculate the thermal conductivity. We additionally built a rotating viscometer with high precision in order to determine the molten salt viscosity. All of these parameters play an important part in the energy storage and transfer calculation and safety evaluation for a system.

  7. Alkali and alkaline earth metal salts of tetrazolone: structurally interesting and excellently thermostable.

    PubMed

    He, Piao; Wu, Le; Wu, Jin-Ting; Yin, Xin; Gozin, Michael; Zhang, Jian-Guo

    2017-07-04

    Tetrazolone (5-oxotetrazole) was synthesized by a moderate strategy through three steps (addition, cyclization and catalytic hydrogenation) avoiding the unstable intermediate diazonium, as reported during the previous preparation. Alkali and alkaline earth metal salts with lithium (1), sodium (2), potassium (3), rubidium (4) caesium (5), magnesium (6), calcium (7), strontium (8) and barium (9) were prepared and fully characterized using elemental analysis, IR and NMR spectroscopy, DSC and TG analysis. All metal salts were characterized via single-crystal X-ray diffraction. They crystallize in common space groups with high densities ranging from 1.479 (1) to 3.060 g cm -3 (5). Furthermore, the crystal structures of 7, 8 and 9 reveal interesting porous energetic coordination polymers with strong hydrogen bond interactions. All new salts have good thermal stabilities with decomposition temperature between 215.0 °C (4) and 328.2 °C (7), significantly higher than that of the reported nitrogen-rich salt neutral tetrazolone. The sensitivities towards impact and friction were tested using standard methods, and all the tetrazolone-based compounds investigated can be classified into insensitive. The flame test of these metal salts supports their potential use as perchlorate-free pyrotechnics or eco-friendly insensitive energetic materials.

  8. Molecular origin of high free energy barriers for alkali metal ion transfer through ionic liquid-graphene electrode interfaces.

    PubMed

    Ivaništšev, Vladislav; Méndez-Morales, Trinidad; Lynden-Bell, Ruth M; Cabeza, Oscar; Gallego, Luis J; Varela, Luis M; Fedorov, Maxim V

    2016-01-14

    In this work we study mechanisms of solvent-mediated ion interactions with charged surfaces in ionic liquids by molecular dynamics simulations, in an attempt to reveal the main trends that determine ion-electrode interactions in ionic liquids. We compare the interfacial behaviour of Li(+) and K(+) at a charged graphene sheet in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, and its mixtures with lithium and potassium tetrafluoroborate salts. Our results show that there are dense interfacial solvation structures in these electrolytes that lead to the formation of high free energy barriers for these alkali metal cations between the bulk and direct contact with the negatively charged surface. We show that the stronger solvation of Li(+) in the ionic liquid leads to the formation of significantly higher interfacial free energy barriers for Li(+) than for K(+). The high free energy barriers observed in our simulations can explain the generally high interfacial resistance in electrochemical storage devices that use ionic liquid-based electrolytes. Overcoming these barriers is the rate-limiting step in the interfacial transport of alkali metal ions and, hence, appears to be a major drawback for a generalised application of ionic liquids in electrochemistry. Some plausible strategies for future theoretical and experimental work for tuning them are suggested.

  9. Alkali metals in addition to acidic pH activate the EvgS histidine kinase sensor in Escherichia coli.

    PubMed

    Eguchi, Yoko; Utsumi, Ryutaro

    2014-09-01

    Two-component signal transduction systems (TCSs) in bacteria perceive environmental stress and transmit the information via phosphorelay to adjust multiple cellular functions for adaptation. The EvgS/EvgA system is a TCS that confers acid resistance to Escherichia coli cells. Activation of the EvgS sensor initiates a cascade of transcription factors, EvgA, YdeO, and GadE, which induce the expression of a large group of acid resistance genes. We searched for signals activating EvgS and found that a high concentration of alkali metals (Na(+), K(+)) in addition to low pH was essential for the activation. EvgS is a histidine kinase, with a large periplasmic sensor region consisting of two tandem PBPb (bacterial periplasmic solute-binding protein) domains at its N terminus. The periplasmic sensor region of EvgS was necessary for EvgS activation, and Leu152, located within the first PBPb domain, was involved in the activation. Furthermore, chimeras of EvgS and PhoQ histidine kinases suggested that alkali metals were perceived at the periplasmic sensor region, whereas the cytoplasmic linker domain, connecting the transmembrane region and the histidine kinase domain, was required for low-pH perception. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  10. Sidewall containment of liquid metal with vertical alternating magnetic fields

    DOEpatents

    Lari, R.J.; Praeg, W.F.; Turner, L.R.; Battles, J.E.; Hull, J.R.; Rote, D.M.

    1990-12-04

    An apparatus is disclosed for containing molten metal using a magnet producing vertical alternating magnetic field positioned adjacent the area in which the molten metal is to be confined. This invention can be adapted particularly to the casting of metal between counter-rotating rollers with the vertical alternating magnetic field used to confine the molten metal at the edges of the rollers. Alternately, the vertical alternating magnetic field can be used as a flow regulator in casting molten metal from an opening in a channel. 9 figs.

  11. Sidewall containment of liquid metal with vertical alternating magnetic fields

    DOEpatents

    Lari, R.J.; Praeg, W.F.; Turner, L.R.; Battles, J.E.; Hull, J.R.; Rote, D.M.

    1988-06-17

    An apparatus for containing molten metal using a magnet producing vertical alternating magnetic field positioned adjacent to the area in which the molten metal is to be confined. This invention can be adapted particularly to the casting of metal between counter-rotating rollers with the vertical alternating magnetic field used to confine the molten metal at the edges of the rollers. Alternately, the vertical alternating magnetic field can be used as a flow regulator in casting molten metal from an opening in a channel. 8 figs.

  12. Porous electrolyte retainer for molten carbonate fuel cell

    DOEpatents

    Singh, Raj N.; Dusek, Joseph T.

    1983-06-21

    A porous tile for retaining molten electrolyte within a fuel cell is prepared by sintering particles of lithium aluminate into a stable structure. The tile is assembled between two porous metal plates which serve as electrodes with fuels gases such as H.sub.2 and CO opposite to oxidant gases such as O.sub.2 and CO.sub.2. The tile is prepared with a porosity of 55-65% and a pore size distribution selected to permit release of sufficient molten electrolyte to wet but not to flood the adjacent electrodes.

  13. Spectroscopic and theoretical investigations of alkali metal linoleates and oleinates

    NASA Astrophysics Data System (ADS)

    Świsłocka, Renata; Regulska, Ewa; Jarońko, Paweł; Lewandowski, Włodzimierz

    2017-11-01

    The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the linoleic (cis-9,cis-12-octadecadienoic) and oleic (cis-9-octadecenoic) acids was investigated. The complementary analytical methods: vibrational (IR, Raman) and electronic (UV) molecular absorption spectroscopy as well as DFT quantum mechanical calculations (charge distribution, angles between bonds, bond lengths, theoretical IR and NMR spectra) were carried out. The regular shifts of bands connected with carboxylate anion in the spectra of studied salts were observed. Some bonds and angles reduced or elongated in the series: acid→Li→Na→K linoleates/oleinates. The highest changes were noted for bond lengths and angles concerning COO- ion. The electronic charge distribution in studied molecules was also discussed. Total atomic charges of carboxylate anion decrease as a result of the replacement of hydrogen atom with alkali metal cation. The increasing values of dipole moment and decreasing values of total energy in the order: linoleic/oleic acid→lithium→sodium→potassium linoleates/oleinates indicate an increase in stability of the compounds.

  14. Ab-Initio Molecular Dynamics Simulations of Molten Ni-Based Superalloys (Preprint)

    DTIC Science & Technology

    2011-10-01

    in liquid–metal density with composition and temperature across the solidification zone. Here, fundamental properties of molten Ni -based alloys ...temperature across the solidification zone. Here, fundamental properties of molten Ni -based alloys , required for modeling these instabilities, are...temperature is assessed in model Ni -Al-W and RENE-N4 alloys . Calculations are performed using a recently implemented constant pressure methodology (NPT) which

  15. Bonding and Mobility of Alkali Metals in Helicenes.

    PubMed

    Barroso, Jorge; Murillo, Fernando; Martínez-Guajardo, Gerardo; Ortíz-Chi, Filiberto; Pan, Sudip; Fernández-Herrera, María A; Merino, Gabriel

    2018-06-04

    In this work, we analyze the interaction of alkali metal cations with [6]- and [14]helicene and the cation mobility of therein. We found that the distortion of the carbon skeleton is the cause that some of the structures that are local minima for the smallest cations are not energetically stable for K+, Rb+, and Cs+. Also, the most favorable complexes are those where the cation is interacting with two rings forming a metallocene-like structure, except for the largest cation Cs+, where the distortion provoked by the size of the cation desestabilizes the complex. As far as mobility is concerned, the smallest cations, particularly Na+, are the ones that can move most efficiently. In [6]helicene, the mobility is limited by the capture of the cation forming the metallocene-like structure. In larger helicenes, the energy barriers for the cation to move are similar both inside and outside the helix. However, complexes with the cation between two layers are more energetically favored so that the movement will be preferred in that region. The bonding analysis reveals that interactions with no less than 50% of orbitalic contribution are taking place for the series of E+-[6]helicene. Particularly, the complexes of Li+ stand out showing a remarkably orbitalic character bonding (72.5 - 81.6%). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. NITRIC ACID PICKLING PROCESS

    DOEpatents

    Boller, E.R.; Eubank, L.D.

    1958-08-19

    An improved process is described for the treatment of metallic uranium surfaces preparatory to being given hot dip coatings. The process consists in first pickling the uraniunn surInce with aqueous 50% to 70% nitric acid, at 60 to 70 deg C, for about 5 minutes, rinsing the acid solution from the uranium article, promptly drying and then passing it through a molten alkali-metal halide flux consisting of 42% LiCl, 53% KCla and 5% NaCl into a molten metal bath consisting of 85 parts by weight of zinc and 15 parts by weight of aluminum

  17. Electromagnetic augmentation for casting of thin metal sheets

    DOEpatents

    Hull, John R.

    1989-01-01

    Thin metal sheets are cast by magnetically levitating molten metal deposited in a mold within a ferromagnetic yoke and between AC conducting coils and linearly displacing the magnetically levitated liquid metal while it is being cooled by the water-cooled walls of the mold to form a solid metal sheet. A conducting shield is electrically coupled to the molten metal sheet to provide a return path for eddy currents induced in the metal sheet by the current in the AC conducting coils. In another embodiment, a DC conducting coil is coupled to the metal sheet for providing a direct current therein which interacts with the magnetic field to levitate the moving metal sheet. Levitation of the metal sheet in both molten and solid forms reduces its contact pressure with the mold walls while maintaining sufficient engagement therebetween to permit efficient conductive cooling by the mold through which a coolant fluid may be circulated. The magnetic fields associated with the currents in the aforementioned coils levitate the molten metal sheet while the mold provides for its lateral and vertical confinement. A leader sheet having electromagnetic characteristics similar to those of the molten metal sheet is used to start the casing process and precedes the molten metal sheet through the yoke/coil arrangement and mold and forms a continuous sheet therewith. The yoke/coil arrangement may be either U-shaped with a single racetrack coil or may be rectangular with a pair of spaced, facing bedstead coils.

  18. Optimization of chlorine fluxing process for magnesium removal from molten aluminum

    NASA Astrophysics Data System (ADS)

    Fu, Qian

    High-throughput and low operational cost are the keys to a successful industrial process. Much aluminum is now recycled in the form of used beverage cans and this aluminum is of alloys that contain high levels of magnesium. It is common practice to "demag" the metal by injecting chlorine that preferentially reacts with the magnesium. In the conventional chlorine fluxing processes, low reaction efficiency results in excessive reactive gas emissions. In this study, through an experimental investigation of the reaction kinetics involved in this process, a mathematical model is set up for the purpose of process optimization. A feedback controlled chlorine reduction process strategy is suggested for demagging the molten aluminum to the desired magnesium level without significant gas emissions. This strategy also needs the least modification of the existing process facility. The suggested process time will only be slightly longer than conventional methods and chlorine usage and emissions will be reduced. In order to achieve process optimization through novel designs in any fluxing process, a system is necessary for measuring the bubble distribution in liquid metals. An electro-resistivity probe described in the literature has low accuracy and its capability to measure bubble distribution has not yet been fully demonstrated. A capacitance bubble probe was designed for bubble measurements in molten metals. The probe signal was collected and processed digitally. Higher accuracy was obtained by higher discrimination against corrupted signals. A single-size bubble experiment in Belmont metal was designed to reveal the characteristic response of the capacitance probe. This characteristic response fits well with a theoretical model. It is suggested that using a properly designed deconvolution process, the actual bubble size distribution can be calculated. The capacitance probe was used to study some practical bubble generation devices. Preliminary results on bubble distribution

  19. Electrolysis of metal oxides in MgCl2 based molten salts with an inert graphite anode.

    PubMed

    Yuan, Yating; Li, Wei; Chen, Hualin; Wang, Zhiyong; Jin, Xianbo; Chen, George Z

    2016-08-15

    Electrolysis of solid metal oxides has been demonstrated in MgCl2-NaCl-KCl melt at 700 °C taking the electrolysis of Ta2O5 as an example. Both the cathodic and anodic processes have been investigated using cyclic voltammetry, and potentiostatic and constant voltage electrolysis, with the cathodic products analysed by XRD and SEM and the anodic products by GC. Fast electrolysis of Ta2O5 against a graphite anode has been realized at a cell voltage of 2 V, or a total overpotential of about 400 mV. The energy consumption was about 1 kW h kgTa(-1) with a nearly 100% Ta recovery. The cathodic product was nanometer Ta powder with sizes of about 50 nm. The main anodic product was Cl2 gas, together with about 1 mol% O2 gas and trace amounts of CO. The graphite anode was found to be an excellent inert anode. These results promise an environmentally-friendly and energy efficient method for metal extraction by electrolysis of metal oxides in MgCl2 based molten salts.

  20. A comprehensive study of the complexation of alkali metal cations by lower rim calix[4]arene amide derivatives.

    PubMed

    Horvat, Gordan; Frkanec, Leo; Cindro, Nikola; Tomišić, Vladislav

    2017-09-13

    The complexation of alkali metal cations by lower rim N,N-dihexylacetamide (L1) and newly synthesized N-hexyl-N-methylacetamide (L2) calix[4]arene tertiary-amide derivatives was thoroughly studied at 25 °C in acetonitrile (MeCN), benzonitrile (PhCN), and methanol (MeOH) by means of direct and competitive microcalorimetric titrations, and UV and 1 H NMR spectroscopies. In addition, by measuring the ligands' solubilities, the solution (transfer) Gibbs energies of the ligands and their alkali metal complexes were obtained. The inclusion of solvent molecules in the free and complexed calixarene hydrophobic cavities was also investigated. Computational (classical molecular dynamics) investigations of the studied systems were also carried out. The obtained results were compared with those previously obtained by studying the complexation ability of an N-hexylacetamidecalix[4]arene secondary-amide derivative (L3). The stability constants of 1 : 1 complexes were determined in all solvents used (the values obtained by different methods being in excellent agreement), as were the corresponding complexation enthalpies and entropies. Almost all of the examined reactions were enthalpically controlled. The most striking exceptions were reactions of Li + with both ligands in methanol, for which the entropic contribution to the reaction Gibbs energy was substantial due the entropically favourable desolvation of the smallest lithium cation. The thermodynamic stabilities of the complexes were quite solvent dependent (the stability decreased in the solvent order: MeCN > PhCN ≫ MeOH), which could be accounted for by considering the differences in the solvation of the ligand and free and complexed alkali metal cations in the solvents used. Comparison of the stability constants of the ligand L1 and L2 complexes clearly revealed that the higher electron-donating ability of the hexyl with respect to the methyl group is of considerable importance in determining the equilibria of the

  1. Corrosion Testing of Zirconia, Beryllia and Magnesia Ceramics in Molten Alkali Metal Carbonates at 900°C

    NASA Astrophysics Data System (ADS)

    Kaplan, Valery; Lubomirsky, Igor

    An electrochemical cell containing molten Li2CO3-Li2O has been proposed for the conversion of the greenhouse gas CO2 to CO, which can then either be used to power gas turbines or converted to methanol. Since efficient electrolysis takes place at 900°C, the materials which can be used in such a cell must satisfy stringent requirements. In the current work, we have examined the static corrosion resistance of zirconia, beryllia and magnesia ceramics at 900°C in the Li2CO3-Li2O mixture and in a Li-Na-K carbonate eutectic mixture with the ultimate objective of identifying suitable electrically insulating materials. Conclusions regarding material stability were based on elemental analysis of the melt, primarily via X-ray photoelectron spectroscopy, a particularly sensitive technique. It was found that magnesia is completely stable for at least 33 hrs in a Li2CO3-Li2O melt, while a combined lithium titanate/lithium zirconate layer forms on the zirconia ceramic as detected by XRD. Under the same melt conditions, beryllia shows considerable leaching into solution. In a Li-Na-K carbonate eutectic mixture containing 10.2 mol% oxide at 900°C under standard atmospheric conditions, magnesia showed no signs of degradation. Stabilization of the zirconia content of the eutectic mixture at 0.01-0.02 at% after 2 hrs is again explained by the formation of a lithium titanate/ lithium zirconate coating. On the basis of these results, we conclude that only magnesia can be satisfactorily used as an insulating material in electrolysis cells containing Li2CO3-Li2O melts.

  2. Candidate molten salt investigation for an accelerator driven subcritical core

    NASA Astrophysics Data System (ADS)

    Sooby, E.; Baty, A.; Beneš, O.; McIntyre, P.; Pogue, N.; Salanne, M.; Sattarov, A.

    2013-09-01

    We report a design for accelerator-driven subcritical fission in a molten salt core (ADSMS) that utilizes a fuel salt composed of NaCl and transuranic (TRU) chlorides. The ADSMS core is designed for fast neutronics (28% of neutrons >1 MeV) to optimize TRU destruction. The choice of a NaCl-based salt offers benefits for corrosion, operating temperature, and actinide solubility as compared with LiF-based fuel salts. A molecular dynamics (MD) code has been used to estimate properties of the molten salt system which are important for ADSMS design but have never been measured experimentally. Results from the MD studies are reported. Experimental measurements of fuel salt properties and studies of corrosion and radiation damage on candidate metals for the core vessel are anticipated. A special thanks is due to Prof. Paul Madden for introducing the ADSMS group to the concept of using the molten salt as the spallation target, rather than a conventional heavy metal spallation target. This feature helps to optimize this core as a Pu/TRU burner.

  3. Process control of GMAW by detection of discontinuities in the molten weld pool

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Carlson, N.M.; Kunerth, D.C.; Johnson, J.A.

    1988-01-01

    The use of ultrasonic sensors to detect discontinuities associated with the molten pool is one phase of a project to automate the welding process. In this work, ultrasonic sensors were used to interrogate the region around the molten/solid interface during gas metal arc welding (GMAW). The ultrasonic echoes from the interface and the molten pool provide information about the quality of the fusion zone and the molten pool. This information can be sent to a controller that can vary the welding parameters to correct the process. Previously ultrasonic shear waves were used to determine if the geometry of the molten/solidmore » interface was indicative of an acceptable weld. In this work, longitudinal waves were used to interrogate the molten weld pool for discontinuities. Unacceptable welding conditions that can result in porosity, incomplete penetration, or undercut were detected. 8 refs., 4 figs.« less

  4. Experimental technique for studying high-temperature phase equilibria in reactive molten metal based systems

    NASA Astrophysics Data System (ADS)

    Ermoline, Alexandre

    The general objective of this work is to develop an experimental technique for studying the high-temperature phase compositions and phase equilibria in molten metal-based binary and ternary systems, such as Zr-O-N, B-N-O, Al-O, and others. A specific material system of Zr-O-N was selected for studying and testing this technique. The information about the high-temperature phase equilibria in reactive metal-based systems is scarce and their studying is difficult because of chemical reactions occurring between samples and essentially any container materials, and causing contamination of the system. Containerless microgravity experiments for studying equilibria in molten metal-gas systems were designed to be conducted onboard of a NASA KC-135 aircraft flying parabolic trajectories. A uniaxial apparatus suitable for acoustic levitation, laser heating, and splat quenching of small samples was developed and equipped with computer-based controller and optical diagnostics. Normal-gravity tests were conducted to determine the most suitable operating parameters of the levitator by direct observations of the levitated samples, as opposed to more traditional pressure mapping of the acoustic field. The size range of samples that could be reliably heated and quenched in this setup was determined to be on the order of 1--3 mm. In microgravity experiments, small spherical specimens (1--2 mm diameter), prepared as pressed, premixed solid components, ZrO2, ZrN, and Zr powders, were acoustically levitated inside an argon-filled chamber at one atmosphere and heated by a CO2 laser. The levitating samples could be continuously laser heated for about 1 sec, resulting in local sample melting. The sample stability in the vertical direction was undisturbed by simultaneous laser heating. Oscillations of the levitating sample in the horizontal direction increased while it was heated, which eventually resulted in the movement of the sample away from its stable levitation position and the laser

  5. Research Investigation Directed Toward Extending the Useful Range of the Electromagnetic Spectrum. [atomic spectra and electronic structure of alkali metals

    NASA Technical Reports Server (NTRS)

    Hartmann, S. R.; Happer, W.

    1974-01-01

    The report discusses completed and proposed research in atomic and molecular physics conducted at the Columbia Radiation Laboratory from July 1972 to June 1973. Central topics described include the atomic spectra and electronic structure of alkali metals and helium, molecular microwave spectroscopy, the resonance physics of photon echoes in some solid state systems (including Raman echoes, superradiance, and two photon absorption), and liquid helium superfluidity.

  6. Universal scaling of potential energy functions describing intermolecular interactions. II. The halide-water and alkali metal-water interactions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Werhahn, Jasper C.; Akase, Dai; Xantheas, Sotiris S.

    2014-08-14

    The scaled versions of the newly introduced [S. S. Xantheas and J. C. Werhahn, J. Chem. Phys.141, 064117 (2014)] generalized forms of some popular potential energy functions (PEFs) describing intermolecular interactions – Mie, Lennard-Jones, Morse, and Buckingham exponential-6 – have been used to fit the ab initio relaxed approach paths and fixed approach paths for the halide-water, X -(H 2O), X = F, Cl, Br, I, and alkali metal-water, M +(H 2O), M = Li, Na, K, Rb, Cs, interactions. The generalized forms of those PEFs have an additional parameter with respect to the original forms and produce fits tomore » the ab initio data that are between one and two orders of magnitude better in the χ 2 than the original PEFs. They were found to describe both the long-range, minimum and repulsive wall of the respective potential energy surfaces quite accurately. Overall the 4-parameter extended Morse (eM) and generalized Buckingham exponential-6 (gBe-6) potentials were found to best fit the ab initio data for these two classes of ion-water interactions. Finally, the fitted values of the parameter of the (eM) and (gBe-6) PEFs that control the repulsive wall of the potential correlate remarkably well with the ionic radii of the halide and alkali metal ions.« less

  7. Liquid surface skimmer apparatus for molten lithium and method

    DOEpatents

    Robinson, Samuel C.; Pollard, Roy E.; Thompson, William F.; Stark, Marshall W.; Currin, Jr., Robert T.

    1995-01-01

    This invention relates to an apparatus for separating two fluids having different specific gravities. The invention also relates to a method for using the separating apparatus of the present invention. This invention particularly relates to the skimming of molten lithium metal from the surface of a fused salt electrolyte in the electrolytic production of lithium metal from a mixed fused salt.

  8. Oxidation of hydrogen halides to elemental halogens

    DOEpatents

    Rohrmann, Charles A.; Fullam, Harold T.

    1985-01-01

    A process for oxidizing hydrogen halides having substantially no sulfur impurities by means of a catalytically active molten salt is disclosed. A mixture of the subject hydrogen halide and an oxygen bearing gas is contacted with a molten salt containing an oxidizing catalyst and alkali metal normal sulfates and pyrosulfates to produce an effluent gas stream rich in the elemental halogen and substantially free of sulfur oxide gases.

  9. Next-Generation Electrochemical Energy Materials for Intermediate Temperature Molten Oxide Fuel Cells and Ion Transport Molten Oxide Membranes.

    PubMed

    Belousov, Valery V

    2017-02-21

    oxygen ion transport in potential MOM materials and MOFC electrolytes. In addition, we consider the rapid oxygen transport in a molten oxide scale formed on a metal surface during catastrophic oxidation and show that the same transport could be used beneficially in MOMs and MOFCs. A polymer model explaining the oxygen transport in molten oxides is also considered. Understanding the oxygen transport mechanisms in oxide melts is important for the development of new generation energy materials, which will contribute to more efficient operation of electrochemical devices at intermediate temperatures. Here we highlight the progress made in developing this understanding. We also show the latest advances made in search of alternative molten oxide materials having high mixed ion electronic and ionic conductivities for use in MOMs and MOFCs, respectively. Prospects for further research are presented.

  10. Rotating disk electrode study of borohydride oxidation in a molten eutectic electrolyte and advancements in the intermediate temperature borohydride battery

    NASA Astrophysics Data System (ADS)

    Wang, Andrew; Gyenge, Előd L.

    2017-08-01

    The electrode kinetics of the NaBH4 oxidation reaction (BOR) in a molten NaOH-KOH eutectic mixture is investigated by rotating disk electrode (RDE) voltammetry on electrochemically oxidized Ni at temperatures between 458 K and 503 K. The BH4- diffusion coefficient in the molten alkali eutectic together with the BOR activation energy, exchange current density, transfer coefficient and number of electrons exchanged, are determined. Electrochemically oxidized Ni shows excellent BOR electrocatalytic activity with a maximum of seven electrons exchanged and a transfer coefficient up to one. X-ray photoelectron spectroscopy (XPS) reveals the formation of NiO as the catalytically active species. The high faradaic efficiency and BOR rate on oxidized Ni anode in the molten electrolyte compared to aqueous alkaline electrolytes is advantageous for power sources. A novel molten electrolyte battery design is investigated using dissolved NaBH4 at the anode and immobilized KIO4 at the cathode. This battery produces a stable open-circuit cell potential of 1.04 V, and a peak power density of 130 mW cm-2 corresponding to a superficial current density of 160 mA cm-2 at 458 K. With further improvements and scale-up borohydride molten electrolyte batteries and fuel cells could be integrated with thermal energy storage systems.

  11. Influence of alkali metal cations/type of activator on the structure of alkali-activated fly ash - ATR-FTIR studies

    NASA Astrophysics Data System (ADS)

    Król, M.; Rożek, P.; Chlebda, D.; Mozgawa, W.

    2018-06-01

    Coal fly ash as a secondary aluminosiliceous raw material that is commonly used in the so-called geopolymerization process has been activated with different alkali hydroxides solutions: LiOH, NaOH and KOH. Changes in the aluminosilicate structure of the material during alkali-activation have been analyzed in detail on the basis of ATR/FT-IR spectra. These changes mainly affect both the integral intensity and FWHM of bands in the range of 1200-950 cm-1, however dehydration and carbonation process can be also analyzed based on obtaining results.

  12. On-Line Control of Metal Processing. Report of the Committee on On-Line Control of Metal Processing

    DTIC Science & Technology

    1989-02-01

    Materials Engineering. His work has concentrated on the electroprocessing of metals in molten salts . He is a member of TMS, AIME, ES, Canadian Institute...continuous ingot casting process with three 32 discrete control loops Figure 4-2 Controller incorporating process model 36 Figure 4-3 Real-time molten ...and others while providing a controlled macrostructure and solidification substructure. In this process, molten metal continuously flows from a

  13. On the origin of alkali metals in Europa exosphere

    NASA Astrophysics Data System (ADS)

    Ozgurel, Ozge; Pauzat, Françoise; Ellinger, Yves; Markovits, Alexis; Mousis, Olivier; LCT, LAM

    2016-10-01

    At a time when Europa is considered as a plausible habitat for the development of an early form of life, of particular concern is the origin of neutral sodium and potassium atoms already detected in its exosphere (together with magnesium though in smaller abundance), since these atoms are known to be crucial for building the necessary bricks of prebiotic species. However their origin and history are still poorly understood. The most likely sources could be exogenous and result from the contamination produced by Io's intense volcanism and/or by meteoritic bombardment. These sources could also be endogenous if these volatile elements originate directly from Europa's icy mantle. Here we explore the possibility that neutral sodium and potassium atoms were delivered to the satellite's surface via the upwelling of ices formed in contact with the hidden ocean. These metallic elements would have been transferred as ions to the ocean at early epochs after Europa's formation, by direct contact of water with the rocky core. During Europa's subsequent cooling, the icy layers formed at the top of the ocean would have kept trapped the sodium and potassium, allowing their future progression to the surface and final identification in the exosphere of the satellite. To support this scenario, we have used chemistry numerical models based on first principle periodic density functional theory (DFT). These models are shown to be well adapted to the description of compact ice and are capable to describe the trapping and neutralization of the initial ions in the ice matrix. The process is found relevant for all the elements considered, alkali metals like Na and K, as well as for Mg and probably for Ca, their respective abundances depending essentially of their solubility and chemical capabilities to blend with water ices.

  14. Recovery of Nickel from Nickel-Based Superalloy Scraps by Utilizing Molten Zinc

    NASA Astrophysics Data System (ADS)

    Yagi, Ryohei; Okabe, Toru H.

    2017-02-01

    With the purpose of developing a new process for recycling nickel (Ni) directly from superalloy scraps, a fundamental study on the extraction and separation of Ni was carried out using molten zinc (Zn) as the extraction medium. In order to examine the reaction between molten Zn and the Ni-based superalloy, superalloy samples and Zn shots were heated at 1173 K (900 °C) for 6 hours. After heating, the superalloy samples fully reacted with Zn and dissolved in molten Zn. The Zn-alloyed sample obtained by slow cooling consisted of two separated upper and lower phases. In the upper part of the sample, only Zn and the Zn-Ni alloys were found; in the lower part, an intermetallic alloy consisting of refractory metals such as rhenium (Re) and tantalum (Ta) was found. This result shows that Ni and refractory metals contained in the scrap can be separated by utilizing the density differences between the Zn-Ni alloy and the refractory metals in molten Zn. Vacuum treatment of the upper part of the Zn-alloyed sample at 1173 K (900 °C) reduced the concentration of Zn in the sample from 97.0 to 0.4 mass pct. After Zn removal, a Ni alloy containing Ni with a purity of 85.3 to 86.1 mass pct and negligible quantities (<0.1 mass pct) of Re and Ta was obtained. Moreover, recovered Zn metal after distillation had a purity of more than 99.9 mass pct. Therefore, this process could be an environmentally sound recycling process that can recover Ni from superalloy scraps without the consumption of Zn or the generation of toxic wastes solutions.

  15. Structural and electronic engineering of 3DOM WO3 by alkali metal doping for improved NO2 sensing performance

    NASA Astrophysics Data System (ADS)

    Wang, Zhihua; Fan, Xiaoxiao; Han, Dongmei; Gu, Fubo

    2016-05-01

    Novel alkali metal doped 3DOM WO3 materials were prepared using a simple colloidal crystal template method. Raman, XRD, SEM, TEM, XPS, PL, Hall and UV-Vis techniques were used to characterize the structural and electronic properties of all the products, while the corresponding sensing performances targeting ppb level NO2 were determined at different working temperatures. For the overall goal of structural and electronic engineering, the co-effect of structural and electronic properties on the improved NO2 sensing performance of alkali metal doped 3DOM WO3 was studied. The test results showed that the gas sensing properties of 3DOM WO3/Li improved the most, with the fast response-recovery time and excellent selectivity. More importantly, the response of 3DOM WO3/Li to 500 ppb NO2 was up to 55 at room temperature (25 °C). The especially high response to ppb level NO2 at room temperature (25 °C) in this work has a very important practical significance. The best sensing performance of 3DOM WO3/Li could be ascribed to the most structure defects and the highest carrier mobility. And the possible gas sensing mechanism based on the model of the depletion layer was proposed to demonstrate that both structural and electronic properties are responsible for the NO2 sensing behavior.Novel alkali metal doped 3DOM WO3 materials were prepared using a simple colloidal crystal template method. Raman, XRD, SEM, TEM, XPS, PL, Hall and UV-Vis techniques were used to characterize the structural and electronic properties of all the products, while the corresponding sensing performances targeting ppb level NO2 were determined at different working temperatures. For the overall goal of structural and electronic engineering, the co-effect of structural and electronic properties on the improved NO2 sensing performance of alkali metal doped 3DOM WO3 was studied. The test results showed that the gas sensing properties of 3DOM WO3/Li improved the most, with the fast response-recovery time and

  16. Development of a High Ionization Efficiency Molten Glass Ion Emitter for TIMS

    NASA Astrophysics Data System (ADS)

    Cheversia, M. B.; Farmer, G.; Koval, C.; David, D.

    2006-12-01

    Thermal ionization mass spectrometry (TIMS) remains the method of choice for many high precision isotope ratio determinations but is handicapped by the use of low efficiency ion emitters. For example, ionization efficiencies from molten glass emitters (Si-gel) used for such elements as Pb, Cr, Ru, and Ag are in the range of 0.05-2%, which limits the sample size and the precision to which isotope ratio determinations for these elements can be made. Our aim is to improve the ionization efficiency of the molten glass ion emitter using electrochemical methods. This work builds on recent observations indicating that many metals doped in borosilicate glasses (eg. Bi, Ag), are emitted from the liquid glass (in vacuo) primarily as the neutral metal atom. Our goal is to increase the proportion of singly charged metal atoms in metal-doped molten glasses via oxidation induced by electrochemical methods and to assess whether such in situ oxidation of metal atoms leads to an increase in emitted metal ions. Our experiments are performed in a vacuum chamber that mimics conditions in the sample chamber of the TIMS. A borosilicate glass sample is placed in a miniature ceramic crucible. The crucible contains working and reference Pt electrodes, and a Pt thermocouple. The entire apparatus is wrapped with a resistively heated Ta wire until temperatures in the glass reach approximately 1400°C, to ensure that the glass is molten. By this method, we have produced simple cyclic voltammograms that suggest that over a 100°C temperature range, the borosilicate glass undergoes a transition from resistive behavior as a solid, to a conductive electrolyte, as a molten liquid glass, as expected. The change is evident as an order of magnitude decrease in resistivity of the glass, as interpreted from the voltammograms. The voltammograms produced for the pure borosilicate glasses represent the baseline against which we will compare the electrochemical characteristics of Pb doped glasses. These

  17. Experimental technique for studying high-temperature phases in reactive molten metal based systems

    NASA Astrophysics Data System (ADS)

    Ermoline, A.; Schoenitz, M.; Hoffmann, V. K.; Dreizin, E. L.

    2004-12-01

    Containerless, microgravity experiments for studying equilibria in molten metal-gas systems have been designed and conducted onboard of a NASA KC-135 aircraft flying parabolic trajectories. An experimental apparatus enabling one to acoustically levitate, laser heat, and splat quench 1-3 mm metal and ceramic samples has been developed and equipped with computer-based controller and optical diagnostics. Normal-gravity testing determined the levitator operation parameters providing stable and adjustable sample positioning. A methodology for optimizing the levitator performance using direct observation of levitated samples was developed and found to be more useful than traditional pressure mapping of the acoustic field. In microgravity experiments, spherical specimens prepared of pressed, premixed powders of ZrO2, ZrN, and Zr, were acoustically levitated inside an argon-filled chamber at one atmosphere and heated by a CO2 laser up to 2800 K. Using a uniaxial acoustic levitator in microgravity, the location of the laser-heated samples could be maintained for about 1 s, so that local sample melting was achieved. Oscillations of the levitating samples in horizontal direction became pronounced in microgravity. These oscillations increased during the sample heating and eventually resulted in moving the sample out of the stable position and away from the laser beam.

  18. Direct Electrolysis of Molten Lunar Regolith for the Production of Oxygen and Metals on the Moon

    NASA Technical Reports Server (NTRS)

    Sirk, Aislinn H. C.; Sadoway, Donald R.; Sibille, Laurent

    2010-01-01

    When considering the construction of a lunar base, the high cost ($ 100,000 a kilogram) of transporting materials to the surface of the moon is a significant barrier. Therefore in-situ resource utilization will be a key component of any lunar mission. Oxygen gas is a key resource, abundant on earth and absent on the moon. If oxygen could be produced on the moon, this provides a dual benefit. Not only does it no longer need to be transported to the surface for breathing purposes; it can also be used as a fuel oxidizer to support transportation of crew and other materials more cheaply between the surface of the moon, and lower earth orbit (approximately $20,000/kg). To this end a stable, robust (lightly manned) system is required to produce oxygen from lunar resources. Herein, we investigate the feasibility of producing oxygen, which makes up almost half of the weight of the moon by direct electrolysis of the molten lunar regolith thus achieving the generation of usable oxygen gas while producing primarily iron and silicon at the cathode from the tightly bound oxides. The silicate mixture (with compositions and mechanical properties corresponding to that of lunar regolith) is melted at temperatures near 1600 C. With an inert anode and suitable cathode, direct electrolysis (no supporting electrolyte) of the molten silicate is carried out, resulting in production of molten metallic products at the cathode and oxygen gas at the anode. The effect of anode material, sweep rate, and electrolyte composition on the electrochemical behavior was investigated and implications for scale-up are considered. The activity and stability of the candidate anode materials as well as the effect of the electrolyte composition were determined. Additionally, ex-situ capture and analysis of the anode gas to calculate the current efficiency under different voltages, currents and melt chemistries was carried out.

  19. Effect of alkali metal ions on the pyrrole and pyridine π-electron systems in pyrrole-2-carboxylate and pyridine-2-carboxylate molecules: FT-IR, FT-Raman, NMR and theoretical studies

    NASA Astrophysics Data System (ADS)

    Świderski, G.; Wojtulewski, S.; Kalinowska, M.; Świsłocka, R.; Lewandowski, W.

    2011-05-01

    The FT-IR, FT-Raman and 1H and 13C NMR spectra of pyrrole-2-carboxylic acid (PCA) and lithium, sodium, potassium, rubidium and caesium pyrrole-2-carboxylates were recorded, assigned and compared in the Li → Na → K → Rb → Cs salt series. The effect of alkali metal ions on the electronic system of ligands was discussed. The obtained results were compared with previously reported ones for pyridine-2-carboxylic acid and alkali metal pyridine-2-carboxylates. Calculations for pyrrole-2-carboxylic acid and Li, Na, K pyrrole-2-carboxylates in B3LYP/6-311++G ** level and Møller-Plesset method in MP2/6-311++G ** level were made. Bond lengths, angles and dipole moments as well as aromaticity indices (HOMA, EN, GEO, I 6) for the optimized structures of pyrrole-2-carboxylic acid (PCA) and lithium, sodium, potassium pyrrole-2-carboxylates were also calculated. The degree of perturbation of the aromatic system of ligand under the influence of metals in the Li → Cs series was investigated with the use of statistical methods (linear correlation), calculated aromaticity indices and Mulliken, NBO and ChelpG population analysis method. Additionally, the Bader theory (AIM) was applied to setting the characteristic of the bond critical points what confirmed the influence of alkali metals on the pyrrole ring.

  20. Effect of restricted geometry on the superconducting properties of low-melting metals (Review Article)

    NASA Astrophysics Data System (ADS)

    Kumzerov, Yu. A.; Naberezhnov, A. A.

    2016-11-01

    This is a review of results from studies of the effect of artificially restricted geometry (the size effect) on the superconducting properties of nanoparticles of low-melting metals (Hg, Pb, Sn, In). Restricted geometrical conditions are created by embedding molten metals under high pressure into nanoporous matrices of two types: channel structures based on chrysotile asbestos and porous alkali-borosilicate glasses. Chrysotile asbestos is a system of parallel nanotubes with channel diameters ranging from 2 to 20 nm and an aspect ratio (channel length to diameter) of up to 107. The glasses are a random dendritic three-dimensional system of interconnected channels with a technologically controllable mean diameter of 2-30 nm. Temperature dependences of the resistance and heat capacity in the region of the superconducting transition and the dependences of the critical temperature on the mean pore diameter are obtained. The critical magnetic fields are also determined.

  1. Method for the melting of metals

    DOEpatents

    White, Jack C.; Traut, Davis E.

    1992-01-01

    A method of quantitatively determining the molten pool configuration in melting of metals. The method includes the steps of introducing hafnium metal seeds into a molten metal pool at intervals to form ingots, neutron activating the ingots and determining the hafnium location by radiometric means. Hafnium possesses exactly the proper metallurgical and radiochemical properties for this use.

  2. Long-Range Adiabatic Corrections to the Ground Molecular State of Alkali-Metal Dimers.

    NASA Astrophysics Data System (ADS)

    Marinescu, M.; Dalgarno, A.

    1997-04-01

    The structure of the long-range limit of the diagonal adiabatic corrections to the ground molecular state of diatomic molecules, may be expressed as a series of inverse powers of internuclear distance, R. The coefficients of this expansion are proportional to the inverse of the nuclear mass. Thus, they may be interpreted as a nuclear mass-dependent corrections to the dispersion coefficients. Using perturbation theory we have calculated the long-range coefficients of the diagonal adiabatic corrections up to the order of R-10. The final expressions are in terms of integrals over imaginary frequencies of products of atomic matrix elements involving Green's functions of complex energy. Thus, in our approach the molecular problem is reduced to an atomic one. Numerical evaluations have been done for all alkali-metal dimers. We acknowledge the support of the U.S. Dept. of Energy.

  3. PREPARATION OF ACTINIDE-ALUMINUM ALLOYS

    DOEpatents

    Moore, R.H.

    1962-09-01

    BS>A process is given for preparing alloys of aluminum with plutonium, uranium, and/or thorium by chlorinating actinide oxide dissolved in molten alkali metal chloride with hydrochloric acid, chlorine, and/or phosgene, adding aluminum metal, and passing air and/or water vapor through the mass. Actinide metal is formed and alloyed with the aluminum. After cooling to solidification, the alloy is separated from the salt. (AEC)

  4. Optical properties from time-dependent current-density-functional theory: the case of the alkali metals Na, K, Rb, and Cs

    NASA Astrophysics Data System (ADS)

    Ferradás, R.; Berger, J. A.; Romaniello, Pina

    2018-06-01

    We present the optical conductivity as well as the electron-energy loss spectra of the alkali metals Na, K, Rb, and Cs calculated within time-dependent current-density functional theory. Our ab initio formulation describes from first principles both the Drude-tail and the interband absorption of these metals as well as the most dominant relativistic effects. We show that by using a recently derived current functional [Berger, Phys. Rev. Lett. 115, 137402 (2015)] we obtain an overall good agreement with experiment at a computational cost that is equivalent to the random-phase approximation. We also highlight the importance of the choice of the exchange-correlation potential of the ground state.

  5. Development of operationally stable inverted organic light-emitting diode prepared without using alkali metals (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Fukagawa, Hirohiko; Morii, Katsuyuki; Hasegawa, Munehiro; Gouda, Shun; Tsuzuki, Toshimitsu; Shimizu, Takahisa; Yamamoto, Toshihiro

    2015-10-01

    The OLED is one of the key devices for realizing future flexible displays and lightings. One of the biggest challenges left for the OLED fabricated on a flexible substrate is the improvement of its resistance to oxygen and moisture. A high barrier layer [a water vapor transmission rate (WVTR) of about 10-6 g/m2/day] is proposed to be necessary for the encapsulation of conventional OLEDs. Some flexible high barrier layers have recently been demonstrated; however, such high barrier layers require a complex process, which makes flexible OLEDs expensive. If an OLED is prepared without using air-sensitive materials such as alkali metals, no stringent encapsulation is necessary for such an OLED. In this presentation, we will discuss our continuing efforts to develop an inverted OLED (iOLED) prepared without using alkali metals. iOLEDs with a bottom cathode are considered to be effective for realizing air-stable OLEDs since the electron injection layer (EIL) can be prepared by fabrication processes that might damage the organic layers, resulting in the enhanced range of materials suitable for EILs. We have demonstrated that a highly efficient and relatively air-stable iOLED can be realized by employing poly(ethyleneimine) as an EIL. Dark spot formation was not observed after 250 days in the poly(ethyleneimine)-based iOLED encapsulated by a barrier film with a WVTR of 10-4 g/m2/day. In addition, we have demonstrated the fabrication of a highly operational stable iOLED utilizing a newly developed EIL. The iOLED exhibits an expected half-lifetime of over 10,000 h from an initial luminance of 1,000 cd/m2.

  6. Methods and apparatuses for making cathodes for high-temperature, rechargeable batteries

    DOEpatents

    Meinhardt, Kerry D; Sprenkle, Vincent L; Coffey, Gregory W

    2014-05-20

    The approaches for fabricating cathodes can be adapted to improve control over cathode composition and to better accommodate batteries of any shape and their assembly. For example, a first solid having an alkali metal halide, a second solid having a transition metal, and a third solid having an alkali metal aluminum halide are combined into a mixture. The mixture can be heated in a vacuum to a temperature that is greater than or equal to the melting point of the third solid. When the third solid is substantially molten liquid, the mixture is compressed into a desired cathode shape and then cooled to solidify the mixture in the desired cathode shape.

  7. Separation of rare earths from transition metals by liquid-liquid extraction from a molten salt hydrate to an ionic liquid phase.

    PubMed

    Rout, Alok; Binnemans, Koen

    2014-02-28

    The solvent extraction of trivalent rare-earth ions and their separation from divalent transition metal ions using molten salt hydrates as the feed phase and an undiluted fluorine-free ionic liquid as the extracting phase were investigated in detail. The extractant was tricaprylmethylammonium nitrate, [A336][NO3], and the hydrated melt was calcium nitrate tetrahydrate, Ca(NO3)2·4H2O. The extraction behavior of rare-earth ions was studied for solutions of individual elements, as well as for mixtures of rare earths in the hydrated melt. The influence of different extraction parameters was investigated: the initial metal loading in the feed phase, percentage of water in the feed solution, equilibration time, and the type of hydrated melt. The extraction of rare earths from Ca(NO3)2·4H2O was compared with extraction from CaCl2·4H2O by [A336][Cl] (Aliquat 336). The nitrate system was found to be the better one. The extraction and separation of rare earths from the transition metals nickel, cobalt and zinc were also investigated. Remarkably high separation factors of rare-earth ions over transition metal ions were observed for extraction from Ca(NO3)2·4H2O by the [A336][NO3] extracting phase. Furthermore, rare-earth ions could be separated efficiently from transition metal ions, even in melts with very high concentrations of transition metal ions. Rare-earth oxides could be directly dissolved in the Ca(NO3)2·4H2O phase in the presence of small amounts of Al(NO3)3·9H2O or concentrated nitric acid. The efficiency of extraction after dissolving the rare-earth oxides in the hydrated nitrate melt was identical to extraction from solutions with rare-earth nitrates dissolved in the molten phase. The stripping of the rare-earth ions from the loaded ionic liquid phase and the reuse of the recycled ionic liquid were also investigated in detail.

  8. [Novel process utilizing alkalis assisted hydrothermal process to stabilize heavy metals both from municipal solid waste or medical waste incinerator fly ash and waste water].

    PubMed

    Wang, Lei; Jin, Jian; Li, Xiao-dong; Chi, Yong; Yan, Jian-hua

    2010-08-01

    An alkalis assisted hydrothermal process was induced to stabilize heavy metals both from municipal solid waste or medical waste incinerator fly ash and waste water. The results showed that alkalis assisted hydrothermal process removed the heavy metals effectively from the waste water, and reduced leachability of fly ash after process. The heavy metal leachabilities of fly ash studied in this paper were Mn 17,300 microg/L,Ni 1650 microg/L, Cu 2560 microg/L, Zn 189,000 microg/L, Cd 1970 microg/L, Pb 1560 microg/L for medical waste incinerator fly ash; Mn 17.2 microg/L, Ni 8.32 microg/L, Cu 235.2 microg/L, Zn 668.3 microg/L, Cd 2.81 microg/L, Pb 7200 microg/L for municipal solid waste incinerator fly ash. After hydrothermal process with experimental condition [Na2CO3 dosage (5 g Na2CO3/50 g fly ash), reaction time = 10 h, L/S ratio = 10/1], the heavy metal removal efficiencies of medical waste incinerator fly ash were 86.2%-97.3%, and 94.7%-99.6% for municipal solid waste incinerator fly ash. The leachabilities of both two kinds of fly ash were lower than that of the Chinese national limit. The mechanism of heavy metal stabilization can be concluded to the chemisorption and physically encapsulation effects of aluminosilicates during its formation, crystallization and aging process, the high pH value has some contribution to the heavy metal removal and stabilization.

  9. Removal of Inclusions from Molten Aluminum by Supergravity Filtration

    NASA Astrophysics Data System (ADS)

    Song, Gaoyang; Song, Bo; Yang, Zhanbing; Yang, Yuhou; Zhang, Jing

    2016-12-01

    A new approach to removing inclusions from aluminum melt by supergravity filtration was investigated. The molten aluminum containing MgAl2O4 spinel and coarse Al3Ti particles was isothermally filtered with different gravity coefficients, different filtering times, and various filtering temperatures under supergravity field. When the gravity coefficient G ≥ 50, the alloy samples were divided automatically into two parts: the upper residue and the lower filtered aluminum. All inclusions (MgAl2O4 and Al3Ti particles) were nearly intercepted in the upper residue by filter felt with average pore size of 44.78 μm. The removal efficiencies of oxide inclusions and Al3Ti particles exceeded 98 and 90 pct, respectively, at G ≥ 50, t = 2 minutes, T = 973 K (700 °C). Besides, the yield of purified aluminum was up to 92.1 pct at G = 600, t = 2 minutes, and T = 973 K (700 °C). The calculations of centrifugal pressure indicated that supergravity filtration could effectively overcome the pressure drop without meeting the rigorous requirement of height of molten metal, especially for using the fine-pore filter medium. Moreover, cake-mode filtration was the major mechanism of supergravity filtration of molten metal in this work.

  10. A theoretical study of the structure and thermochemical properties of alkali metal fluoroplumbates MPbF3.

    PubMed

    Boltalin, A I; Korenev, Yu M; Sipachev, V A

    2007-07-19

    Molecular constants of MPbF3 (M=Li, Na, K, Rb, and Cs) were calculated theoretically at the MP2(full) and B3LYP levels with the SDD (Pb, K, Rb, and Cs) and cc-aug-pVQZ (F, Li, and Na) basis sets to determine the thermochemical characteristics of the substances. Satisfactory agreement with experiment was obtained, including the unexpected nonmonotonic dependence of substance dissociation energies on the alkali metal atomic number. The bond lengths of the theoretical CsPbF3 model were substantially elongated compared with experimental estimates, likely because of errors in both theoretical calculations and electron diffraction data processing.

  11. A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide.

    PubMed

    Ng, Chee Koon; Wu, Jie; Hor, T S Andy; Luo, He-Kuan

    2016-09-27

    Binary catalyst systems comprising a cationic Ru-CNC pincer complex and an alkali metal salt were developed for selective hydroboration of CO 2 utilizing pinacolborane at r.t. and 1 atm CO 2 , with the combination of [Ru(CNC Bn )(CO) 2 (H)][PF 6 ] and KOCO 2 t Bu producing formoxyborane in 76% yield. A bicyclic catalytic mechanism was proposed and discussed.

  12. Catalysis using hydrous metal oxide ion exchanges

    DOEpatents

    Dosch, Robert G.; Stephens, Howard P.; Stohl, Frances V.

    1985-01-01

    In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

  13. Catalysis using hydrous metal oxide ion exchangers

    DOEpatents

    Dosch, R.G.; Stephens, H.P.; Stohl, F.V.

    1983-07-21

    In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

  14. Investigation of Coatings Which Prevent Molten Aluminum/Water Explosions

    NASA Astrophysics Data System (ADS)

    León, D. D.; Richter, R. T.; Levendusky, T. L.

    The Aluminum Association contracted Alcoa in 1995 to identify and test new protective coatings for casting pits as a replacement for Porter International's 7001 (Tarset Standard). Three new coatings have been identified through a series of selection criteria including: 1) A standardized splash test used to evaluate personal protective clothing, 2) An industry-standard molten metal explosion test, 3) A multiple-exposure test to measure durability, and 4) An external shock impact test. The results of this program will be reviewed. This study only tested protective coatings at the "in-service cure time", as defined by the manufacturer. These curing times can be excessive for a production casting facility. The Aluminum Association has contracted Alcoa in a second program to investigate the effect of reduced cure times on adhesion and their effectiveness in preventing molten metal/water explosions. A status update of this new two year program is provided.

  15. The electrochemical reduction processes of solid compounds in high temperature molten salts.

    PubMed

    Xiao, Wei; Wang, Dihua

    2014-05-21

    Solid electrode processes fall in the central focus of electrochemistry due to their broad-based applications in electrochemical energy storage/conversion devices, sensors and electrochemical preparation. The electrolytic production of metals, alloys, semiconductors and oxides via the electrochemical reduction of solid compounds (especially solid oxides) in high temperature molten salts has been well demonstrated to be an effective and environmentally friendly process for refractory metal extraction, functional materials preparation as well as spent fuel reprocessing. The (electro)chemical reduction of solid compounds under cathodic polarizations generally accompanies a variety of changes at the cathode/melt electrochemical interface which result in diverse electrolytic products with different compositions, morphologies and microstructures. This report summarizes various (electro)chemical reactions taking place at the compound cathode/melt interface during the electrochemical reduction of solid compounds in molten salts, which mainly include: (1) the direct electro-deoxidation of solid oxides; (2) the deposition of the active metal together with the electrochemical reduction of solid oxides; (3) the electro-inclusion of cations from molten salts; (4) the dissolution-electrodeposition process, and (5) the electron hopping process and carbon deposition with the utilization of carbon-based anodes. The implications of the forenamed cathodic reactions on the energy efficiency, chemical compositions and microstructures of the electrolytic products are also discussed. We hope that a comprehensive understanding of the cathodic processes during the electrochemical reduction of solid compounds in molten salts could form a basis for developing a clean, energy efficient and affordable production process for advanced/engineering materials.

  16. Porous electrolyte retainer for molten carbonate fuel cell. [lithium aluminate

    DOEpatents

    Singh, R.N.; Dusek, J.T.

    1979-12-27

    A porous tile for retaining molten electrolyte within a fuel cell is prepared by sintering particles of lithium aluminate into a stable structure. The tile is assembled between two porous metal plates which serve as electrodes with fuels gases such as H/sub 2/ and CO opposite to oxidant gases such as O/sub 2/ and CO/sub 2/. The tile is prepared with a porosity of 55 to 65% and a pore size distribution selected to permit release of sufficient molten electrolyte to wet but not to flood the adjacent electrodes.

  17. An alkali-metal ion extracted layered compound as a template for a metastable phase synthesis in a low-temperature solid-state reaction: preparation of brookite from K0.8Ti1.73Li0.27O4.

    PubMed

    Ozawa, Tadashi C; Sasaki, Takayoshi

    2010-03-15

    We have designed a new approach to synthesize brookite, i.e., to extract alkali-metal ions from K(0.8)Ti(1.73)Li(0.27)O(4) (KTLO) and to apply simultaneous heat treatment to the remaining lepidocrocite-type layers of TiO(6) octahedra. For the alkali-metal ion extraction and the simultaneous heat treatment, KTLO was heated at 400 degrees C with polytetrafluoroethylene (PTFE) in flowing Ar. PTFE has been found to be an effective agent to extract strongly electropositive alkali-metal ions from KTLO because of the strong electronegativity of F as its component. The product of this reaction consists of a mixture of brookite, K(2)CO(3), LiF, and PTFE derivatives, indicating the complete extraction of K(+) and Li(+) from KTLO and formation of brookite from the lepidocrocite-type layer of TiO(6) octahedra as a template. This brookite has a partial replacement of O(2-) with F(-) and/or slight oxygen deficiency; thus, its color is light-bluish gray. Fully oxidized brookite formation and complete decomposition of PTFE derivatives have been achieved by further heating in flowing air, and coproduced alkali-metal salts have been removed by washing in water. Powder X-ray diffraction, Raman spectroscopy, and chemical analysis results have confirmed that the final brookite product treated at 600 degrees C is single phase, and it is white. The method to extract alkali-metal ions from a crystalline material using PTFE is drastically different from the common methods such as soft-chemical and electrochemical reactions. It is likely that this new synthetic approach is applicable to other layered systems to prepare a diverse family of compounds, including novel metastable ones.

  18. Systems and Methods for Fabricating Objects Including Amorphous Metal Using Techniques Akin to Additive Manufacturing

    NASA Technical Reports Server (NTRS)

    Hofmann, Douglas (Inventor)

    2017-01-01

    Systems and methods in accordance with embodiments of the invention fabricate objects including amorphous metals using techniques akin to additive manufacturing. In one embodiment, a method of fabricating an object that includes an amorphous metal includes: applying a first layer of molten metallic alloy to a surface; cooling the first layer of molten metallic alloy such that it solidifies and thereby forms a first layer including amorphous metal; subsequently applying at least one layer of molten metallic alloy onto a layer including amorphous metal; cooling each subsequently applied layer of molten metallic alloy such that it solidifies and thereby forms a layer including amorphous metal prior to the application of any adjacent layer of molten metallic alloy; where the aggregate of the solidified layers including amorphous metal forms a desired shape in the object to be fabricated; and removing at least the first layer including amorphous metal from the surface.

  19. Esr Spectra of Alkali-Metal Atoms on Helium Nanodroplets: a Theoretical Model for the Prediction of Helium Induced Hyperfine Structure Shifts

    NASA Astrophysics Data System (ADS)

    Hauser, Reas W.; Filatov, Michael; Ernst, Wolfgang E.

    2013-06-01

    We predict He-droplet-induced changes of the isotropic HFS constant a_{HFS} of the alkali-metal atoms M = Li, Na, K and Rb on the basis of a model description. Optically detected electron spin resonance spectroscopy has allowed high resolution measurements that show the influence of the helium droplet and its size on the unpaired electron spin density at the alkali nucleus. Our theoretical approach to describe this dependence is based on a combination of two well established techniques: Results of relativistic coupled-cluster calculations on the alkali-He dimers (energy and HFS constant as functions of the binding length) are mapped onto the doped-droplet-situation with the help of helium-density functional theory. We simulate doped droplets He_{N} with N ranging from 50 to 10000, using the diatomic alkali-He-potential energy curves as input. From the obtained density profiles we evaluate average distances between the dopant atom and its direct helium neighborhood. The distances are then set in relation to the variation of the HFS constant with binding length in the simplified alkali-He-dimer model picture. This method yields reliable relative shifts but involves a systematic absolute error. Hence, the absolute values of the shifts are tied to one experimentally determined HFS constant for ^{85}Rb-He_{N = 2000}. With this parameter choice we obtain results in good agreement with the available experimental data for Rb and K^{a,b} confirming the predicted 1/N trend of the functional dependence^{c}. M. Koch, G. Auböck, C. Callegari, and W. E. Ernst, Phys. Rev. Lett. 103, 035302-1-4 (2009) M. Koch, C. Callegari, and W. E. Ernst, Mol. Phys. 108 (7), 1005-1011 (2010) A. W. Hauser, T. Gruber, M. Filatov, and W. E. Ernst, ChemPhysChem (2013) online DOI: 10.1002/cphc.201200697

  20. Monte Carlo simulation of the mixed alkali effect with cooperative jumps

    NASA Astrophysics Data System (ADS)

    Habasaki, Junko; Hiwatari, Yasuaki

    2000-12-01

    In our previous works on molecular dynamics (MD) simulations of lithium metasilicate (Li2SiO3), it has been shown that the long time behavior of the lithium ions in Li2SiO3 has been characterized by the component showing the enhanced diffusion (Lévy flight) due to cooperative jumps. It has also been confirmed that the contribution of such component decreases by interception of the paths in the mixed alkali silicate (LiKSiO3). Namely, cooperative jumps of like ions are much decreased in number owing to the interception of the path for unlike alkali-metal ions. In the present work, we have performed a Monte Carlo simulation using a cubic lattice in order to establish the role of the cooperative jumps in the transport properties in a mixed alkali glass. Fixed particles (blockage) were introduced instead of the interception of the jump paths for unlike alkali-metal ions. Two types of cooperative motions (a pull type and a push type) were taken into account. Low-dimensionality of the jump path caused by blockage resulted in a decrease of a diffusion coefficient of the particles. The effect of blockage is enhanced when the cooperative motions were introduced.