| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for producing an ammonium tungstate aqueous solution by which an ammonium tungstate aqueous solution of high purity can be produced by removing impurities. <P>SOLUTION: The method for producing an ammonium tungstate aqueous solution includes: a step of bringing an aqueous solution of an alkali metal tungstate having a pH of 9 or more and 14 or less and containing impurities into contact with an anion exchange resin; and a step of bringing a low concentration anion-containing aqueous solution into contact with the anion exchange resin after coming into contact with the alkali metal tungstate aqueous solution. The low concentration anion-containing solution has a pH of 9 or more, and the low concentration anion-containing solution contains at least one kind of anion in a low concentration, selected from chloride ion, nitrate ion and sulfate ion. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
