Gte Products Corporation

Gte Sylvania Incorporated

Brice E Martin

Lucretia R Quatrini

Clarence D Vanderpool

Joseph E Ritsko

Richard G Gingerich

Michael J Cheresnowsky

Howard L Acla

Martin C Vogt

Alan R Schwartz

Allen Myron Alper

Marie B Terlizzi

Carl William Boyer

Processes are described for preparing pure ammonium molybdate from impure roasted molybdenum concentrates. An aqueous solution of sulfuric acid, ammonium sulfate, and ammonium persulfate is contacted with impure molybdenum concentrate to solubilize a major portion of the impurities. The resulting molybdenum concentrate is digested in ammonium hydroxide under conditions that maximize iron precipitation and removal. The resulting ammonium molybdate solution is separated from the sludge and further purified by chelating cation exchange resin in the ammonium form.

Process for purifying molybdenum trioxide

Gold is recovered from a material including gold and molybdenum or tungsten by contacting the material with an aqueous solution of hydrogen iodide and iodine to solubilize the gold without solubilizing the molybdenum or tungsten and recovering the gold from the solution.

Process for recovering gold

Coarse particle size zinc sulfide is treated with a solution of alkali metal halide to make it adaptable for hot-pressing into shaped, polycrystalline windows which is more transparent in the visible to near visible and infrared spectral regions than untreated coarse particle size zinc sulfide.

Treatment of coarse particle size zinc sulfide to improve visual and

Tungsten is recovered from tungsten ore concentrates in the form of sodium tungstate by a basic process in which ground ore is first digested in a sodium hydroxide solution followed by diluting the solution to dissolve sodium tungstate separating the solution from the caustic insoluble sludge and crystallizing soluble sodium tungstate, wherein the present invention permits improved recovery of tungsten from difficult to process ores by the process steps of comminuting said tungsten ore concentrate to a particle size less than 325 mesh, adding said comminuted ore to aqueous sodium hydroxide at a concentration of at least 10 molar and digesting at a temperature of from about 75.degree. C. to 150.degree. C. for a sufficient period of time to convert substantially all of the tungsten values to soluble sodium tungstate, and diluting the mixture to reduce the sodium hydroxide concentration to between about 4.5 and 5.5 molar at a temperature below about 90.degree. C. to substantially dissolve all of the sodium tungstate.

Tungsten recovery from tungsten ore concentrates by caustic digestion

Tungsten is recovered from tungsten ore concentrates in the form of sodium tungstate by a basic process in which ground ore is first digested in a sodium hydroxide solution followed by diluting the solution to dissolve sodium tungstate separating the solution from the caustic insoluble sludge and crystallizing soluble sodium tungstate, wherein the present invention permits improved recovery of tungsten from difficult to process ores by the process steps of comminuting said tungsten ore concentrate to a particle size less than about 200 mesh, dispersing the comminuted ore to separate agglomerated particles, adding the dispersed ore to aqueous sodium hydroxide at a concentration of at least 10 molar and digesting at a temperature of from about 75.degree. C. to 150.degree. C. for a sufficient period of time to convert substantially all of the tungsten values to soluble sodium tungstate, and diluting the mixture to reduce the sodium hydroxide concentration to between about 4.5 and 5.5 molar at a temperature below about 90 degrees centigrade to substantially dissolve all of the sodium tungstate.

Tungsten is recovered from tungsten ore concentrates in the form of sodium tungstate by a basic process in which ground ore is first digested in a sodium hydroxide solution followed by diluting the solution to dissolved sodium tungstate separating the solution from the caustic insoluble sludge and crystallizing soluble sodium tungstate, wherein the present invention permits improved recovery of tungsten from difficult to process ores by the process steps of comminuting said tungsten ore concentrate to a particle size less than about 200 mesh, adding the comminuted ore to an aqueous solution of sodium hydroxide at a temperature from about 10 to about 30 degrees centigrade, dispersing said comminuted ore in the aqueous solution of sodium hydroxide prior to digestion, digesting at a temperature of from about 75.degree. C. to about 150.degree. C. for a sufficient period of time to convert substantially all of the tungsten values to dissolvable sodium tungstate, and diluting the mixture to reduce the sodium hydroxide concentration to between about 4.5 and 5.5 molar at a temperature below about 90.degree. C. to substantially dissolve all of the sodium tungstate.

In a process for recovering tungsten from cemented tungsten carbide, the tungsten carbide is oxidized to form an oxidized product and the oxidized product is digested in an aqueous solution of alkali metal hydroxide to form a soluble portion containing tungsten values and an insoluble residue portion. According to the improved process of the present invention, tungsten values are recovered from the insoluble residue portion by mixing the insoluble portion with an alkali metal carbonate to form a resulting mixture, roasting the resulting mixture in an atmosphere containing oxygen to oxidize the insoluble portion and form another product which is leached with water to recover soluble tungsten values.

Process for removing tungsten from cemented tungsten carbide

In the recovery of molybdenum and rhenium values from sulfide ores, silica impurity is reduced to low levels by adding alumina to a carbonate fusion mix in an amount sufficient to combine with the silica present to form insoluble aluminum silicates, thus preventing its removal from the fusion mass during removal of soluble molybdenum and rhenium values by leaching, and thereby avoiding the necessity for conventional subsequent precipitation and filtration removal steps.

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Towanda, PA, United States of America

Brice E Martin