Process for producing ammonium paratungstate

摘要

A process is disclosed for producing ammonium paratungstate which involves adding hexamethylenetetramine to a first solution of ammonium tungstate, adjusting the pH to about 2 with an acid to form a precipitate which contains the major portion of the tungsten and the hexamethylenetetramine and separating the precipitate from the resulting mother liquor. The tungsten hexamethylenetetramine precipitate is then dissolved in aqueous ammonia to form a second ammonium tungstate solution which is then heated at from about 90 DEG C. to about 100 DEG C. to form a precipitate essentially all of which is ammonium paratungstate and a mother liquor which contains essentially all of the hexamethylenetetramine. The ammonium paratungstate precipitate is then separated from the mother liquor.