Showing papers on "Tungstate published in 1972"

Nuclear Magnetic Resonance and Quadrupole Coupling in Hydrous and Anhydrous Sodium Molybdate and Sodium Tungstate Spinel

Abstract: The nuclear magnetic resonance of 23Na in powder samples of hydrous and anhydrous sodium molybdate and sodium tungstate has been investigated. The anhydrous compounds crystallize in the cubic spinel of type H11, Fd3m presumably with ionic charges of 1 + and 6 + on the metals. The 23Na quadrupole couplings are the largest yet observed for this nucleus and have values of 2.62 and 2.48 MHz in the molybdate and tungstate respectively, as determined from both first- and second-order effects on the magnetic resonance spectrum. These couplings have negligible temperature dependences. Using charges of 1 + and 6 + for the metal ions, assuming that the oxygens are in their ideal positions in the spinel structure and neglecting any contributions from oxygen dipoles and quadrupoles, the electric field gradient was calculated to be 12 × 1013 e.s.u./cm3, in good agreement with the experimental gradient of 7.5 × 1013 e.s.u./cm3. Preliminary measurements of the sodium spin–lattice relaxation time, using tone-burst techni...

Method for the manufacture of powdered tungsten carbide containing electrode material

Abstract: Method for making electrode material containing tungsten in powdered form A tungsten compound selected from a halide or oxide, a tungstic acid, a tungstate, a thiotungstate is mixed with a solid or liquid cokable substance A solution of such organic substance may also be used The organic substance in the mixture is precoked and the tungsten carburized or sulfidized

Process for the extraction of tungsten from an aqueous alkaline solution

Abstract: THE PRESENT INVENTION COMPRISES A SOLVENT EXTRACTION PROCESS FOR THE RECOVERY OF TUNGSTEN FROM AN AQUEOUS ALKALINE SOLUTION. THE SOLUTION IS SULFIDIZED TO CONVERT THE TUNGSTEN THEREIN TO A THIOTUNGSTATE SPECIES AND SUBSEQUENTLY CONTACTED WITH AN ORGANIC PHASE COMPRISING AN EXTRACTANT IN AN ORGANIC DILUENT, WHEREBY THE THROTUNGSTATE FORMS A COMPLEX WITH THE EXTRACTANT IN THE ORGANIC PHASE. THE ORGANIC PHASE CONTAINING THE THIOTUNGSTATE COMPLEX IS RECOVERED AND HYDROLYZED TO CONVERT THE THIOTUNGSTATE COMPLEX TO A TUNGSTATE COMPLEX WHEREBY THE TUNGSTEN IS READILY RECOVERABLE USING KNOWN TECHNIQUES.

Method for the oxidizing alpha, beta-unsaturated aldehydes to alpha, beta-unsaturated carboxylic acids

Abstract: Alpha , Beta -unsaturated aldehydes are oxidized to Alpha , Beta -unsaturated carboxylic acids by contacting the Alpha , Beta -unsaturated aldehyde with air or oxygen and steam at 200*350*C and at atmospheric or elevated pressure in the presence of a catalyst so as to convert the aldehyde to the corresponding carboxylic acid. The catalyst comprises a mixture of oxides of the elements antimony, molybdenum, vanadium and tungsten and/or compounds of said elements and oxygen wherein the atomic ratio of the elements is as follows: 1 to 60 : 12 : 0.5 to 25 : 0.1 to 12. The catalyst is made by intimately mixing under agitation aqueous solutions or suspensions of the oxides or other compounds, for instance antimony oxide, ammonium molybdate, ammonium vanadate and ammonium tungstate, and possibly a carrier material and preferably bringing the mixture to boiling point, then separating the catalyst mass from the aqueous phase, drying it and calcining it at 225*-275*C, followed by heating in air for 15-60 minutes at 350*-475*C.

Inorganic coatings for aluminous metals

Abstract: SILICEOUS COATINGS HAVING GOOD ADHESION, HARDNESS AND SMOOTHNESS AND CORROSION RESISTANCE ARE PRODUCED ON THE SURFACE OF AN ALUMINOUS METAL BY IMMERIISING THE METAL IN AN AQUEOUS BATH OF AN ALKALI SILICATE, CONTAINING AN ALKALI CHROMATE, MOLYBDATE, OR TUNGSTATE, AND FURTHER CONTAINING AN ALKALI CARBONATE, PHOSPHATE, OR BORATE, AND PASSING CURRENT THROUGH SAID BATH AT A VOLTAGE PREDOMINANTLY POSITIVE AND SUFFICIENT TO CAUSE A UNIFORM SCINTILLATION OR FLASHING AT THE ANODE SURFACE. THE COATING THUS OBTAINED IS DECORATIVE AND SCRATCH-RESISTANT AND ALSO PROVIDES A GOOD BASE FOR A COVER COATING SUCH AS A PLASTIC

Coated coil emissive electrode

Abstract: A coated coil emissive electrode of the type utilized in fluorescent lamps and a method for making such an electrode. The electrode includes a tungsten coil, a bonding layer of an emissive form of barium tungstate coating said tungsten coil, and a layer of porous barium oxide coating said barium tungstate, said barium tungstate bonding said barium oxide to said tungsten coil. The electrode is made by coating said tungsten coil wuth a mixture of barium peroxide, cellulose nitrate and butyl cellosolve and heating said coated coil to the exothermal decomposition temperature of said cellulose nitrate. The exothermal decompositon of said cellulose nitrate raises the temperature of the barium peroxide to its exothermal decomposition temperature thereby forming said bonding layer of the emissive form of barium tungstate and releasing bubbles of oxygen causing the pores in said barium oxide.

Specific Separation of Gallium, Gold, and Magnesium, and Separation of Be-AI-Ga on Stannic Molybdate Papers

Abstract: Chromatography of 47 cations in 11 solvent systems has been performed on stannic molybdate ion exchange papers. Some difficult separations, e.g., Rb from Cs, Al-Be-Ga, and Tl-In, and specific separations of Ga, Au and Mg from numerous metal ions, have been achieved. R F values of some common metal ions on these papers have been compared with R F values of these cations on stannic tungstate and stannic phosphate papers. The preparation of papers is easy and the results are reproducible.

Production of clear,sealed anodized films

Abstract: IT IS CONVENTIONAL TO SEAL ANODIZED FILMS PRODUCED ON ALUMINUM SURFACES BY ELECTROYLSIS IN A SULFURIC ACID ELECTROLYTE BY NEUTRALIZING SUCH FILMS, WASHING THEM AND THEN CONTACTING THEM WITH A SEALING SOLUTION. AN EFFECTIVE SOLUTION FOR SEALING SUCH FILMS SO THAT THEY ARE CORROSION RESISTANT AND SO THAT THEY ARE SUBSTANTIALLY CLEAR IN APPEARANCE CAN CONSIST ESSENTIALLY OF 0.1 TO ABOUT 5% BY WEIGHT OF CHROMIC OXIDE PRESENT IN THE FORM OF A COMPOUND SELECTED FROM THE GROUP CONSISTING ESSENTIALLY OF CHROMIC ACID AND AMMONIUM AND ALKALI METAL CHROMATE AND DICHROMATE SALTS AND MIXTURES THEREOF AND FROM ABOUT (1.5 TO ABOUT 10% BY WEIGHT OF TUNGSTATE IONS PRESENT IN THE FORM OF A COMPOUND SELECTED FROM THE GROUP CONSISTING ESSENTIALLY OF AMMONIUM AND ALKALI METAL TUNGSTATE AND METATUNGSTATE SALTS AND MIXTURES THEREOF. THE SOLUTION USED MAY CONTAINS AN ALKALI METAL HYDROXIDE OR SIMILAR PH ADJUSTING AGENT AND SHOULD HAVE A PH OF FROM ABOUT 4.5 TO ABOUT 8 AND SHOULD BE AT A TEMPERATURE OF FROM ABOUT 130*F. TO IMMEDIATELY BELOW THE BOILING POINT OF THE SOLUTION.