Patents Assigned to Institute Po Obshta I Neorganichna Chimia
  • Patent number: 4278641
    Abstract: Rhenium and tungsten are recovered from a rhenium tungsten alloy by electrochemically dissolving the alloy in substantially 4 to 5 normal sodium hydroxide to form a rhenium-containing solution, solvent extracting the rhenium-containing solution with an organic heteroatom-containing solvent (e.g. pyridine) or acetone to form a second solution of the solvent containing rhenium, distilling the solvent from the second solution to form a raffinate containing rhenium, adding sulfuric acid to the raffinate to adjust the pH thereof to about 1, extracting tungsten from the raffinate with a solution of trioctylamine in kerosene containing octyl alcohol, and subjecting the raffinate containing sodium perrhenate to ion exchange to eventually convert it to ammonium perrhenate.
    Type: Grant
    Filed: January 16, 1980
    Date of Patent: July 14, 1981
    Assignee: Institute Po Obshta I Neorganichna Chimia
    Inventors: Nikolov Y. Petrov, Maria M. Pavlova, Ognyan D. Bojkov