Gte Products Corporation

Gte Products Corporaton

Timothy A Brunelli

Michael J Cheresnowsky

Tai K Kim

Robin W Munn

Keith E Landmesser

A method is disclosed for purifying molybdenum which involves adding to an ammoniacal ammonium molybdate solution containing the impurities of phosphorus and arsenic with the phosphorus concentration being from about 0.01 to about 0.12 g/l, a soluble magnesium salt to form a precipitate comprising magnesium ammonium salts of the phosphorus and arsenic, and to form a purified ammonium molybdate solution. The amount of the magnesium salt is sufficient to result in a concentration of from about 0.005 to about 0.04 moles/l in the ammoniacal ammonium molybdate solution. The resulting purified ammonium molybdate contains no greater than about 0.01 g P/l. The precipitate is separated from the purified solution which is then contacted with a chelating cation exchange resin supplying a sufficient amount of a cation to result in removal of the major portion of the magnesium ions from the purified solution and form a further purified ammonium molybdate solution.

Purification of molybdenum

A process is disclosed for removing potassium from relatively impure molybdenum trioxide. The process involves contacting the impure molybdenum trioxide containing greater than about 600 weight parts potassium per million with a first acid leach which consists essentially of nitric acid and ammonium nitrate at a temperature of at least about 50.degree. C. for a sufficient time and at above a 2 molar concentration of said nitric acid and an ammonium nitrate concentration of from about 1.5 to about 2 molar in said first acid leach to solubilize the major portion of the potassium and form a once leached molybdenum trioxide containing the remaining portion of the potassium which is separated from the resulting potassium containing acid leach and contacted with a second leach solution substantially similar to the first acid leach followed by separating the resulting twice leached molybdenum trioxide from the resulting potassium containing second leach. The twice leached molybdenum trioxide is contacted with sufficient water to remove any residual impurities followed by removal of the resulting wash water.

Purification of molybdenum trioxide

A process is disclosed for removing potassium from a relatively impure molybdenum trioxide and forming a molybdenum compound of high purity. The process involves first contacting the impure molybdenum trioxide with an acid leach which consists essentially of a mineral acid and the ammonium salt of the mineral acid in a weight ratio of above about 3 to 1 of acid leach to molybdenum trioxide at a sufficient temperature and for a sufficient time to solubilize the major portion of the potassium and form a leached molybdenum trioxide, followed by separating the leached molybdenum trioxide from the resulting potassium containing acid leach. The leached molybdenum trioxide is then water washed to remove residual impurities and the washed molybdenum trioxide is dissolved in ammonium hydroxide having an ammonium concentration sufficient to form an ammonium molybdate solution from which is crystallized the highly pure molybdenum compound.

Processes are described for preparing pure ammonium molybdate from impure roasted molybdenum concentrates. An aqueous solution of nitric acid and ammonium nitrate 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

A process is disclosed for producing molybdenum metal from an ammonium molybdate salt. The process involves heating the salt in a reducing atmosphere at a temperature of no greater than about 775.degree. C. for a sufficient time to convert the major portion of the salt to molybdenum dioxide, and heating the molybdenum dioxide in a reducing atmosphere at a temperature of no greater than about 1095.degree. C. to convert the major portion of the molybdenum dioxide to molybdenum metal.

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Towanda, PA, United States of America

Timothy A Brunelli