Patent ID: 8974674
Filing Date: 2015-03-10
Classification: C01G,C01P,G10L

Abstract:
1. A method for producing an ammonium tungstate aqueous solution, comprising the steps of: decreasing a pH of a solution containing tungstate ions and vanadate ions to not less than 7 and not more than 9 by using sulfuric acid to generate polyacid cluster ions of tungsten and vanadium; bringing said solution having the pH decreased, into contact with an anion exchange resin; eluting the vanadate ions from said anion exchange resin, by bringing said polyacid cluster ions of tungsten and vanadium adsorbed in said anion exchange resin into contact with a basic solution having a pH of 9 or higher to decompose said polyacid cluster ions of tungsten and vanadium into the tungstate ions and the vanadate ions; eluting the tungstate ions remaining in said anion exchange resin with an aqueous solution after eluting the vanadate ions to obtain a discharged solution containing the tungstate ions; adding sulfuric acid to said discharged solution containing the tungstate ions to generate poly tungstate ions; bringing said discharged solution having said sulfuric acid added therein, into contact with said anion exchange resin; bringing said anion exchange resin with which said discharged solution is brought into contact, into contact with an ammonia solution; and recovering a solution discharged from said anion exchange resin in the step of bringing said anion exchange resin into contact with said ammonia solution.