METHOD OF EXTRACTION OF MOLYBDENUM AND/OR TUNGSTEN FROM ACID SOLUTIONS Russian patent published in 1997 - IPC

FIELD: chemical technology. SUBSTANCE: interaction of urea and formaldehyde is carried in the closed space at their molar ratio = 1:(1.5-2), at pH = 3-4.5 adding part of the parent solution containing molybdenum and/or tungsten. Reaction is carried out for 3-5 min at stirring. Then at continuous stirring the formed vapor-gaseous mixture is removed and passed through filter containing ammonium carbonate followed by combustion. The remained part of the parent solution is added to the urea-formaldehyde reaction mixture and stirred for 10-90 min. Deposit containing molybdenum and/or tungsten is separated. Deposit is mixed with new portion of the parent solution, stirred for 10-90 min, precipitate is separated and treated again with the parent solution up to the complete saturation with molybdenum and/or tungsten. EFFECT: improved method of extraction. 2 cl