Abstract: 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.

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 method for producing extra fine cobalt metal powder (up to 1.7 FSSS) by the digestion of cobalt pentammine chloride in a dilute ammonium hydroxide solution to form a cobalt-containing precipitate, followed by reducing the precipitate in a hydrogen atmosphere to cobalt metal powder, is improved by: (a) adding NaOH to the mother liquor containing cobalt species in solution, to form a cobalt-containing precipitate; and (b) either heating the precipitate in hydrogen to reduce it to cobalt metal powder or recycling the precipitate as a cobalt source for the formation of cobalt pentammine chloride. The final cobalt metal powder is useful, for example, as a starting material in the manufacture of cemented carbides.

Abstract: Fine particle size cobalt metal powder is prepared by treating an aqueous solution of a soluble cobaltic ammine halide with a sufficient amount of a soluble metallic hydroxide to form a cobalt containing precipitate. The precipitate is separated from the solution and reduced in a reducing atmosphere to produce metallic cobalt.