Showing papers on "Tungstate published in 1980"
TL;DR: In this paper, the luminescence of doped and undoped PbMoO4 and PbWO4 single crystals was measured and assigned to the 3T11A1 transition in the tetrahedral MoO42−(WO42+) group.
215 citations
62 citations
Patent•
14 Feb 1980
TL;DR: A chromium-free process for phosphatizing a metal surface provides for applying to the surface an aqueous acidic solution having pH 1.5 to 3.0 and containing phosphate; a metal cation of valence two or greater; molybdate, tungstate, vanadate, niobate or tantalate ions; and drying the solution on the surface without rinsing.
Abstract: A chromium-free process for phosphatizing a metal surface provides for applying to the surface an aqueous acidic solution having pH 1.5 to 3.0 and containing phosphate; a metal cation of valence two or greater; molybdate, tungstate, vanadate, niobate or tantalate ions; and drying the solution on the surface without rinsing.
51 citations
TL;DR: Raman spectra of 7-29% tungsten trioxide, prepared by wet or dry impregnation and calcined at 823/sup 0/K, showed no formation of aluminum tungstate to a detection limit of 1.
50 citations
32 citations
TL;DR: In this article, a monoclinic symmetry was established for the Bi2−xLaxWO6 solid-solution system, where the structure consists of Bi2-LaxO2 layers interleaved with WO4 layers with no oxygens in common.
27 citations
20 citations
Journal Article•
TL;DR: Tungstate prevented the formation of active nitrate reductase in growing rumen bacteria capable of nitrate reduction, but did not directly inhibit the enzyme activity of all strains tested.
18 citations
TL;DR: A conversion coating was deposited on tin in a tungsten bath and examined by surface analysis techniques (scanning electron microscopy, energy-dispersive X-ray microanalysis and Auger electron spectroscopy) and by electrochemical techniques.
15 citations
TL;DR: The results suggest that tungstate treatment inactivates the molybdoenzymes in this cyanobacterium.
13 citations
Patent•
24 Oct 1980
TL;DR: In this article, the authors proposed a method to reduce the blackening of a glow tube wall, improve the preservation ratio of luminous flux, and reduce lamp voltage rise by adding an appropriate amount of barium tungstate to a composite Tungstate.
Abstract: PURPOSE:To reduce the blackening of a glow tube wall, improve the preservation ratio of luminous flux, and reduce lamp voltage rise by adding an appropriate amount of barium tungstate to a composite tungstate. CONSTITUTION:An electron emissive material of which principal components are composite tungstate consisting of barium tungstate and tungstates of other alkaline earth metals and 2-20wt%, on the basis of the composite tungstate, barium tungstate (BaWO4) is coated on an electrode. An especially desirable range of barium tungstate (BaWO4) is 3-15wt%.
TL;DR: In this paper, the solubilities of silver molybdate, silver tungstate, copper tungstane, and copper tengstane in water have been determined over the temperature range 20-40°C using ion-selective electrodes.
TL;DR: In this paper, the luminescence properties of undoped Bi2W2O9 and of Bi 2W 2O9-Mo and Bi 2 W2O 9-Eu are reported.
Abstract: The luminescence properties of undoped Bi2W2O9 and of Bi2W2O9-Mo and Bi2W2O9-Eu are reported. The emission is ascribed to tungstate emission. The Eu3+ ions occupy Bi3+ as well as interstitial sites. Energy transfer from the host lattice to the different types of Eu3+ ions depends on the excitation wavelengths.
Patent•
12 Jun 1980
TL;DR: In this paper, a process for removing molybdenum values from aqueous solutions containing tungsten values comprising sulfidizing said solution to an extent sufficient to convert substantially all of the values to a thiomolybdate species was described.
Abstract: Disclosed is a process for removing molybdenum values from aqueous solutions containing tungsten values comprising sulfidizing said solution to an extent sufficient to convert substantially all of the molybdenum values to a thiomolybdate species, said sulfidizing being substantially less than the extent necessary to convert substantially all of said tungsten values to a thiotungstate species and contacting the resulting solution containing the thiomolybdate complex ion with a suitable amount of an organic extractant for a sufficient period of time to preferentially extract the thiomolybdate complex ion into the organic extractant, said organic extractant comprising an aromatic organic solvent and a quaternary ammonium compound of the formula R3 (CH3)N+ A-, wherein R is an alkyl group having from about 8 to 10 carbon atoms and A is an anion derived from a mineral acid.
TL;DR: In this article, a new inorganic membrane system, viz. zirconyl tungstate, has been investigated for its functional, diffusive and electrochemical properties, and the diffusion of electrolytes as determined by the Willis method reveal dependence of permeability of ions on the porosity, charge on the membrane matrix, membrane conductivity, charge and size of permeating ions.
Patent•
20 Sep 1980
TL;DR: In this article, the authors proposed a method to obtain a long-life 700W lamp having good starting-up property by controlling within a specific range the weight of electrode with an electron-radiating substance film composed of a mixture of an alkaline earth metal tungstate, Y2O3, and BeO or La2O 3.
Abstract: PURPOSE:To obtain a long-life 700W lamp having good starting-up property by controlling within a specific range the weight of electrode with an electron-radiating substance film composed of a mixture of an alkaline earth metal tungstate, Y2O3, and BeO or La2O3. CONSTITUTION:The luminous tube 1 of 700W rated power is wound with the starting auxiliary conductor 11 on its periphery and also filled with a buffering metal, Na, and Xe of 100-300 Torr. Also, the electrodes 3 provided on both ends are sheathed with an electron-radiating substance containing a tungstate of an alkaline earth metal including at least Ba, Y2O3, and at least one of BeO and La2O3. And, the weight of each electrode 3 with its core wire is regulated to 1.46-2.50g, and also the diameter of the core wire and the number of turns of tungsten coil are regulated so that the temperature of each electrode 3 at the rated current becomes 1200-1500 deg.C.
TL;DR: In this article, a NaF addition to a Na2WO4 -WO3 flux yielded large single crystals up to 0.8 mm thick, which were free of inclusions.
Abstract: Bi2WO6 is a polar materials in the bismuth titanate family, Bi2Mn-1RnO3n+3. Additions of NaF to a Na2WO4 - WO3 flux yielded large single crystals up to 0.8 mm thick, which were free of inclusions. Total impurities were less than 500 ppm, and the crystals contained no apparent twin boundaries.
Patent•
09 Dec 1980
TL;DR: In this article, a process for removing tungsten, and molybdenum generally, as the tungstate and/or the Molybdate anion, from aqueous solutions, e.g. brines by contacting such solutions with a high-surface area oxide selected from the group consisting of manganese and iron oxides, preferably MANGANESE or IR hydrous oxide, is presented.
Abstract: The instant invention relates to a process for removing tungsten, and/or molybdenum generally, as the tungstate and/or the molybdate anion, from aqueous solutions, e.g. brines by contacting such solutions with a high-surface area oxide selected from the group consisting of manganese and iron oxides, preferably manganese or iron hydrous oxide, whereby tungsten or molybdenum is adsorbed on said high-surface area oxide. The instant process provides selectivity for tungsten as well as molybdenum even though they are present in solutions containing various other materials such as sodium, potassium, calcium, etc. ions. This process is preferably applicable to removal of tungsten from high pH brines such as a brine having a pH of at least 9, for example greater than 10. The oxide adsorbent may be regenerated by contacting with an aqueous solution having a pH higher than the brine from which the tungsten and/or the molybdenum has been removed.
Patent•
23 Oct 1980
TL;DR: In this article, the authors presented a method to easily manufacture filamentous titania glass fiber in bulk by heat melting a blend of alkali metal titanate and molybdate or the like followed by crystal growth, extraction of the M2O component and heat dehydration.
Abstract: PURPOSE:To easily manufacture filamentous titania glass fiber in bulk by heat melting a blend of alkali metal titanate and alkali metal molybdate or the like followed by crystal growth, extraction of the alkali metal component and heat dehydration CONSTITUTION:Alkali metal titanate of formula M2OnTiO2 (where M is Na, K, Rb or Cs and n is 1-6) and alkali metal molybdate or alkali metal tungstate as flux are blended in a molar ratio of 5:95-50:50 This blend is heat melted at 800- 1300 degC, and by crystal growth through slow cooling or other process a fibrous alkali metal titanate single crystal body is formed It is then treated with an aq acid soln to extract the M2O component, and the resulting filamentous titania hydrate is heat dehydrated at 500 degC or below to form titania glass fiber This fiber is used as a cation exchanger, an adsorbent, a catalyst carrier, etc
Patent•
15 Feb 1980
TL;DR: In this article, a tungsten extraction process using an organic extractant is described, where the major constituent is tri-isooctyl amine and the solvent is a mixture of alkyl benzenes having molecular weights of either 120, 134 or 148.
Abstract: A tungsten extraction process wherein tungsten values are extracted from an aqueous alkali metal tungstate solution by an organic extractant, then stripped from the extractant is improved by using an organic solution consisting essentially of from about 6 to about 10 percent by volume an extractant that is a mixture of trialkyl amines wherein the major constituent is tri-isooctyl amine and from about 90 to about 94 percent by volume of a solvent that is a mixture of alkyl benzenes having molecular weights of either 120, 134 or 148.
Patent•
02 Oct 1980TL;DR: In this article, a method of preparing diaminodiphenylmethanes and higher homologues thereof is described, which comprises the step of condensing aniline and formaldehyde in the presence of a silver tungstate catalyst.
Abstract: Covers a method of preparing diaminodiphenylmethanes and higher homologues thereof which comprises the step of condensing aniline and formaldehyde in the presence of a silver tungstate catalyst.
TL;DR: In this article, the authors studied the kinetics of strontium tungstate crystallization from sodium tung-state melts in platinum crucibles by differential thermal analysis at crystallization temperaturesT0=800, 900 and 1000° by continuous cooling at ratesRT=40, 120 and 200° per hour.
Abstract: The kinetics of strontium tungstate crystallization from sodium tungstate melts in platinum crucibles were studied by differential thermal analysis at crystallization temperaturesT0=800, 900 and 1000° by continuous cooling at ratesRT=40, 120 and 200° per hour. Heterogeneous nuclei that first formed on the metal platinate particles in the solution during the induction periods (t) grew to small crystallites (¯l). The main crystal growth started after the development of some excess solute concentration (Δ¯C) at the end of the induction temperatures (¯T). For the first 80% crystallization, the average crystal lengths (lτ) varied with the growth time (τ) according to the relation\(l_\tau ^2 = (\bar l)^2 + + 4\bar k_{D_1 } M\Delta \bar C\) where\(\bar k_{D1} \) is the diffusion rate constant at temperatures nearT, andM is the metal salt molecular weight. The initial growth rates and the ratioslτ2/τ depended onΔ¯C instead ofRT The last 20% growth was controlled only by the rate of development of the excess solute concentration.