Process for the manufacture of ammonium tungstate ammonium paratungstate, ammonium metatungstate and hydrated tungsten trioxide

摘要

Ammonium tungstate, ammonium paratungstate, ammonium metatungstate or hydrated tungsten trioxide is produced by passing tungstate anions through an anion exchange membrane into an aqueous solution containing ammonium cations under the driving force of an electrical potential for a time sufficient to achieve a pH within the range in which the desired tungsten compound will form.