Chemistry of inorganic compounds – Treating mixture to obtain metal containing compound – Group vib metal
Patent
1977-08-16
1978-09-19
Carter, Herbert T.
Chemistry of inorganic compounds
Treating mixture to obtain metal containing compound
Group vib metal
423 54, 423 58, 423 55, C01G 4100
Patent
active
041155130
ABSTRACT:
To obtain highly purified, lamp grade ammonium paratungstate crystals from any of several different tungsten ores, the ore is reduced to finely divided status and slurried in heated HCl solution to convert tungsten values to WO.sub.3.H.sub.2 O. Recovered tungstic oxide is washed and dissolved in heated aqueous solution of sodium carbonate or sodium hydroxide with the pH maintained at about 8 to 8.5 to form soluble sodium tungstate. Sodium hydroxide is added to raise the pH to about 10.5 to 11.5, and magnesium chloride is added in amount sufficient to somewhat neutralize the solution. Sodium hydroxide is added to raise the pH to about 10.5 to 11.5 to precipitate as hydroxide the magnesium and additional metallic impurities. At least one of ammonium sulfide and thioacetamide is and the heated solution is acidified to a pH in the range from about 2 to 3 to precipitate any molybdenum as MoS.sub.3. The tungstate solution is then contacted with an organic, water-immiscible ion exchange liquid in which the active ingredient is an amine salt to extract the tungsten values. Tungsten values are then stripped from the ion exchange liquid with ammonium hydroxide to form ammonium tungstate solution, which in turn is separated. From the ammonium tungstate solution is crystallized highly purified ammonium paratungstate. The process is adaptable to continuous type operation.
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Cleary James G.
Kulkarni Avinash D.
Carter Herbert T.
Palmer W. D.
Westinghouse Electric Corp.
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