Osram Sylvania Inc.

Gte Products Corporation

Global Tungsten & Powders Corp.

Thomas A Wolfe

Michael J Miller

David L Houck

Raj P Singh

Judy A Belinski-Wolfe

Clarence D Vanderpool

Tai K Kim

Michael J Cheresnowsky

Martin C Vogt

Michael R Pierce

Brian J Payne

Raj Pal Singh Gaur

Chung Nin Chau

Scott A Braymiller

Claraence D Vanderpool

Jia-Ming Chern

A phosphor blend for an electroluminescent lamp is described that comprises a green-emitting electroluminescent phosphor and a red-emitting photoluminescent phosphor, the blend exhibiting an x color coordinate from 0.220 to 0.350 and a y color coordinate from 0.450 to 0.475 when stimulated by an electric field.

Yellow-emitting phosphor blend for electroluminescent lamps

A novel molybdenum compound, ammonium dodecamolybdomolybdate (AMM), is described which may be used in the manufacture of molybdenum metal and molybdenum carbide powders. The molybdenum compound is a dodecaheteropoly acid salt having a Keggin-type structure wherein molybdenum resides in both the hetero as well as peripheral atomic positions. The novel compound has the general formula (NH)MoMoO&#xb7;6HO. Because of its low solubility, the compound can be crystallized efficiently and at a high purity from ammonium molybdate solutions.

Ammonium dodecamolybdomolybdate and method of making

There is presented an electroluminescent phosphor powder of copper-activated zinc sulfide particles that has a size distribution with a D50 value of less than 12 &#x3bc;m, and more preferably less than 10 &#x3bc;m. The powder is preferably made by a method that includes the steps of combining copper-doped zinc sulfide with sulfur, zinc oxide and a chloride-containing flux to form a first mixture; preliminarily firing the first mixture and milling the preliminarily fired first mixture to form a milled material having a D50 value of less than or equal to about 5 &#x3bc;m; blending the milled material with sulfur, zinc oxide and a chloride-containing flux to form a second mixture; firing the mixture in a first firing step at a temperature in a range of about 1020&#xb0; C. to about 1080&#xb0; C. to form a hexagonal zinc sulfide material; inducing defects into the hexagonal zinc sulfide material; firing the hexagonal zinc sulfide material in a second firing step at a temperature in a range of about 650&#xb0; C. to about 850&#xb0; C. to form an electroluminescent phosphor; and sifting the electroluminescent phosphor to provide an electroluminescent phosphor powder comprising phosphor particles that have a size distribution with a D50 value of less than 12 &#x3bc;m. The step of inducing defects may be accomplished by milling, mulling or sonification of the mixture.

Electroluminescent phosphor powder with D50 value of less than 12 &#x3bc;m and method of making

An electrochemical displacement-deposition method for making composite metal powders is described. The method is carried out by combining tungsten or molybdenum metal particles with particles of silver oxide or copper oxide in an aqueous hydroxide solution. Heat is applied to the solution to cause the oxide particles to convert to silver or copper metal particles which are substantially adhered to the refractory metal particles. Unlike conventional methods, it is not necessary to heat the oxide powders to a very high temperature in a reducing atmosphere in order to form the composite metal powder.

Electrochemical displacement-deposition method for making composite metal powders

A novel molybdenum compound, ammonium dodecamolybdomolybdate (AMM), is described which may be used in the manufacture of molybdenum metal and molybdenum carbide powders. The molybdenum compound is a dodecaheteropoly acid salt having a Keggin-type structure wherein molybdenum resides in both the hetero as well as peripheral atomic positions. The novel compound has the general formula (NH ) Mo MoO .6H O. Because of its low solubility, the compound can be crystallized efficiently and at a high purity from ammonium molybdate solutions.

A method for purifying a phosphorus containing scheelite ore is described wherein the calcite phase is selectively dissolved prior to dissolution of the apatite phase. Selective dissolution of the calcite produces several benefits: (1) a usable calcium solution, (2) enhanced apatite dissolution, and (3) lower volumes of toxic acid solution for disposal.

Purification of phosphorus containing scheelite ore

A simple, cost effective method for reclaiming tungsten values from tungsten-thoria has been invented. The method involves reacting the tungsten-thoria with molten sodium hydroxide to form a soluble sodium tungstate and an insoluble residue of thoria, cooling the melt, dissolving the melt in water, and filtering to separate the insoluble residue of thoria from the dissolved sodium tungstate. The method resulting in substantially all of the tungsten values being reclaimed as sodium tungstate and acutely reducing the amount of radioactive material for disposal.

Reclamation of tungsten values from tungsten-thoria

A method is provided whereby tungsten values are recovered from ferrotungsten by completely oxidizing the ferrotungsten at high temperatures in an oxygen atmosphere followed by digestion with sodium hydroxide to form soluble sodium tungstate. The sodium tungstate is then purified by conventional means. The method may be used to recover at least about 90% of the tungsten values present in the ferrotungsten.

Recovery of tungsten from ferrotungsten

A process for reducing the average particle size of an ammonium paratungstate powder having the steps of heating the ammonium paratungstate powder at a temperature of between about 110.degree. C. to about 205.degree. C. for a time sufficient to reduce the average particle size of the ammonium paratungstate powder by at least 20 percent.

Process for reducing the average particle size of ammonium paratungstate

In the manufacture of ammonium paratungstate, sulfide is added to a tungsten-containing solution in order to precipitate molybdenum sulfide. Volatiles, including sulfides, evolved during this process are collected in a caustic scrubbing solution. The sulfide values in the caustic scrubbing solution may be reused to precipitate molybdenum sulfide by first treating the caustic scrubbing solution with alkaline earth chloride or sulfate to precipitate out alkaline earth carbonate.

Removal of carbonate from caustic sulfide solution

A method for producing pure cobalt metal powder involves the removal of divalent cationic impurities from a trivalent hexamine cobalt chloride solution. This solution is then decomposed to an insoluble cobalt oxide-containing material, from which pure cobalt metal powder is obtained through a chemical reduction process.

Growing community of inventors

Towanda, PA, United States of America

Thomas A Wolfe