AMMONIUM PARATUNGSTATE PRODUCTION PROCESS Russian patent published in 1998 - IPC

FIELD: industrial inorganic synthesis. SUBSTANCE: initial concentrates are cleaved by return soda-alkali solutions, which are corrected according to their admixtures without recurring to their neutralization by means of inorganic and organic reagents, after which tungsten is isolated directly from soda-alkali solution by the aid of solid or liquid anion exchangers. Productive tungsten solutions are obtained when extracting tungsten by ammonia solutions followed by treating anion exchanger by alkaline solutions. EFFECT: enhanced process efficiency and reduced amount of injurious waste. 6 cl, 8 tbl