Abstract: A process is disclosed for producing high purity silicon nitride. The process involves contacting an organic compound which can be decomposed into silicon dioxide with essentially anhydrous ammonia at ambient temperature to form a two phase system consisting essentially of ammonia gas and the vapor of the organic compound and heating the two phase system at a sufficient temperature for a sufficient time to form the high purity silicon nitride.

Abstract: A process is disclosed for recovering chromium from a chromium bearing material containing cobalt, molybdenum, and tungsten. The process involves roasting the material and alkali metal compound at a temperature of at least about 400.degree. C. for a sufficient time to react the alkali metal compound with the material and form a reacted mixture containing essentially all of the chromium, molybdenum, and tungsten as alkali salts. The reacted mixture is water leached to dissolve the alkali salts and form a leach solution containing essentially all of the chromium, molybdenum, and tungsten, and a leach solid containing essentially all of the cobalt. After separation of the leach solution from the leach solid, the pH of the leach solution is adjusted to from about 0.5 to about 3.0 with an acid and a sufficient amount of a reducing agent is added to reduce essentially all of the chromium to the trivalent state.

Abstract: A process is disclosed for recovering tungsten, iron, and manganese from tungsten bearing material. The process involves digesting the material in a sulfur dioxide solution at a sufficient temperature for a sufficient time to form a digestion solution containing the major portion of the scandium, iron, and manganese, and a digestion solid containing the major portion of the tungsten which is separated from the digestion solution. The major portion of the scandium is extracted from the digestion solution with an organic consisting essentially of an extracting agent which is essentially a mixture of alkyl primary amines which are present in an amount sufficient to extract the major portion of the scandium without extracting appreciable amounts of iron and manganese, and the balance an essentially aromatic solvent. After separation of the scandium containing organic from the raffinate, the organic is stripped of the scandium with hydrochloric acid which is then separated from the stripped organic.

Abstract: A method is disclosed for recovering tungsten from a relatively dilute ammoniacal tungsten solution. The method involves adding hexamethylenetetramine to the tungsten solution in an amount sufficient to form a hexamethylenetetramine complex then adjusting the pH to from about 1.0 to about 2.0 with a mineral acid to form a precipitate of the complex containing at least about 99% of the tungsten, and separating the precipitate from the resulting mother liquor.

Abstract: A process is disclosed for producing ammonium paratungstate which involves adding hexamethylenetetramine to a first solution of ammonium tungstate, adjusting the pH to about 2 with an acid to form a precipitate which contains the major portion of the tungsten and the hexamethylenetetramine and separating the precipitate from the resulting mother liquor. The tungsten hexamethylenetetramine precipitate is then dissolved in aqueous ammonia to form a second ammonium tungstate solution which is then heated at from about 90.degree. C. to about 100.degree. C. to form a precipitate essentially all of which is ammonium paratungstate and a mother liquor which contains essentially all of the hexamethylenetetramine. The ammonium paratungstate precipitate is then separated from the mother liquor.

Abstract: A process is disclosed for recovering tungsten, scandium, iron, and manganese from tungsten bearing material. The process involves digesting the material in sufficient sulfuric acid at a sufficient temperature for a sufficient time in the presence of a reducing agent to form a digestion solution containing the major portion of the scandium, iron, and manganese, and a digestion residue containing the major portion of the tungsten, separating the digestion solution from the digestion residue and extracting essentially all of the scandium from the solution with an organic consisting essentially of an extracting agent which is a dialkyl phosphoric acid which is present in an amount sufficient to extract essentially all of the scandium without extracting appreciable amounts of iron and manganese, and the balance an essentially aromatic solvent.

Abstract: A method is disclosed for producing relatively pure ammonium paratungstate from an impure tungsten solution. The method involves first adding hexamethylenetetramine to the tungsten solution and adjusting the pH to from about 1.0 to about 2.0 with a mineral acid to form a first precipitate of a tungsten hexamethylenetetramine product, which is then separated from its mother liquor. The precipitate is then slurried in water and the pH adjusted to from about 7.0 to about 8.5 with ammonia to dissolve the precipitate. The resulting solution is then adjusted to from about 1.0 to about 2.0 with a mineral acid to form a second precipitate of the tungsten hexamethylenetetramine product which is then separated from its mother liquor. The second precipitate is then slurried in a solution of water and sufficient ammonia to form ammonium paratungstate which crystallizes out on evaporation of the slurry. The ammonium paratungstate is then separated from its mother liquor.

Abstract: A method is disclosed for producing pure cobalt metal powder. The method involves reducing a cobalt containing source material to produce an intermediate cobalt metal, contacting this intermediate with an ammoniacal ammonium halide solution and a catalyst with oxidation to form a solution of hexamminecobalt(III) ions, removing insoluble material, and adding a sufficient amount of a halide salt to the solution to precipitate hexamminecobalt(III) halide which is separated from the mother liquor. The hexamminecobalt(III) halide precipitate is dissolved in water and the pH is adjusted to greater than about 10 with a base, while the solution is heated at a sufficient temperature for a sufficient time to form an insoluble cobalt oxide containing material which is separated from its mother liquor and reduced to pure cobalt metal powder.

Abstract: A method is disclosed for producing crystalline ammonium metatungstate from ammonium paratungstate. The method involves heating the ammonium paratungstate with microwave radiation, then heating an aqueous slurry of the heated ammonium paratungstate at from about 80.degree. to about 100.degree. C. at relatively constant volume until the pH of the slurry becomes stabilized at from about 5.8 to about 6.8, adjusting the pH of the slurry to from about 4.2 to about 30, digesting the resulting pH adjusted slurry at from about 80.degree. to about 100.degree. C. for from about 2 to about 6 hours to form a solution of ammonium metatungstate, concentrating the resulting solution, separating insolubles from the solution, and crystallizing ammonium metatungstate from the concentrated solution.

Abstract: A process is disclosed for recovering cobalt from an alloy containing other metals as chromium, tungsten, etc. The process involves first adding the alloy to fused sodium hydroxide at a temperature of from about 750.degree. C. to about 1000.degree. C. to form a reaction mixture, the amount of sodium hydroxide being sufficient to subsequently form sodium salts which are essentially those of chromium and tungsten and hydroxides which are essentially those of cobalt and nickel. The reaction mixture is then heated at a sufficient temperature for a sufficient time while introducing an oxidizing gas into the reaction mixture to form a melt which consists essentially of the sodium salts and the hydroxides, followed by cooling the melt. The cooled melt is then contacted with sufficient water to form a solution containing the major portion of the sodium salts and a solid containing the major portion of the hydroxides, followed by separating the solid from the solution.

Abstract: A process is disclosed for recovering cobalt and chromium from a cobalt and chromium containing alloy. The process involves first digesting the alloy in concentrated hydrochloric acid at a sufficient temperature for a sufficient time to form a first solution containing the major portion of the cobalt, chromium, and any iron and nickel present in the alloy and a first solid and separating the first solution from the first solid. Oxalic acid is then added to the first solution in an amount sufficient to subsequently precipitate the major portion of the cobalt and any iron and nickel contained in the first solution followed by adjustment of the ph to from about 1 to about 2 with a base and maintaining the temperature below about 20.degree.

Abstract: A process is disclosed for producing pure molybdenum which involves contacting a molybdate solution with a true liquid alkaloid in an amount sufficient to form an alkaloid-molybdenum compound with essentially all of the molybdenum. The resulting alkaloid-treated solution is adjusted to a pH of from about 2 to 4 to form a precipitate consisting essentially of the compound and a mother liquor. The precipitate is then separated from the mother liquor and dissolved in ammonium hydroxide to form a two phase system consisting essentially of an alkaloid phase and a molybdenum phase followed by separation of the two phases. A pure ammonium molybdate compound is then crystallized from the molybdenum phase.

Abstract: A process is disclosed for recovering molybdenum from molybdenum disulfide. The process involves forming a slurry of the molybdenum disulfide in a solution of an alkali metal hydroxide, the amount of hydroxide being sufficient to react with at least a portion of the molybdenum disulfide to form an alkali metal molybdate and an alkali sulfate, heating the slurry in an oxidizing atmosphere at an elevated temperature and pressure and for a sufficient time to effect the conversion to the molybdate, and separating the pregnant liquor containing the molybdate from any residue. To the pregnant liquor is then added a sufficient amount of a hexamine to form a hexamine-molybdenum compound containing the major portion of the molybdenum, followed by adjusting the pH to from about 1.5 to about 3.8 to precipitate the major portion of the hexamine-molybdenum compound, and separating the compound from the resulting mother liquor.

Abstract: A process is disclosed for recovering cobalt in a relatively pure form from an impure cobalt bearing material. The process involves digesting the material in hydrochloric acid to form a solution essentially all of the cobalt and some impurities and insoluble material containing the remainder of the impurities, separating the solution from the insolubles, adding an oxalate producing compound in an amount sufficient to subsequently convert essentially all of the cobalt to cobalt oxalate to the solution, adjusting the pH of the oxalate treated solution to from about 1.5 to about 2.0 with a base to precipitate the cobalt, and finally separating the precipitate from the resulting mother liquor.

Abstract: In a process for producing fine cobalt metal powder by reduction of a cobalt hydroxide precipitate, the cobalt hydroxide precipitate is heat treated prior to reduction at a selected temperature for reducing the Fisher Sub Sieve Size of the finally produced cobalt metal powder.

Abstract: A process is disclosed wherein tungsten is recovered from hazardous waste material containing said tungsten, arsenic, and other impurities which can consist of magnesium, phosphorus, and silicon and the resulting waste is treated to render it nonhazardous according to EPA standards for arsenic. Said process involves digesting said hazardous waste material in an aqueous solution of an alkali metal hydroxide, adjusting the pH of the resulting solution to about 11.0 to about 13.0 with NaOH to precipitate essentially all of the magnesium and silicon species, filtering the digestion mix to remove the solids from said resulting solution which contains about 80 to about 100% of said tungsten and essentially none of said magnesium and said silicon, slurrying the hazardous solids in hot water, and adding to the slurry a ferric salt solution to precipitate ferric hydroxide, filtering this mixture to give a solid which passes the EPA standard test for solids with respect to arsenic.

Abstract: In a process for producing fine size cobalt metal powder from scrap material containing brazing compositions, the silver ions are removed by cementation with iron to form an insoluble mixture which is subsequently treated with concentrated hydrochloric acid to solubilize the silver which is then precipitated as silver chloride.

Abstract: Ammonium molybdate is produced from molybdenum disulfide concentrate by contacting the concentrate with an aqueous solution of ammonium chloride and chlorine at suitable concentrations and for a sufficient period of time to solubilize molybdenum disulfide present in said concentrate as molybdate ions and form a solution of ammonium molybdate.

Abstract: In a process for recovering refractory metal values from a refractory metal carbide cemented with a metal binder. The coated cemented carbide is treated with sulfuric acid to deteriorate the coating.

Abstract: A fine cobalt metal powder is produced from pieces of relatively pure cobalt by dissolving the cobalt pieces in an aqueous solution of hydrogen iodide and iodine and forming a cobalt containing solid which is subsequently reduced to a fine cobalt metal powder.