| 摘要 |
In the present invention there is disclosed a process for preparing pure ammonium metallates of tungsten, molybdenum, vanadium, chromium and rhenium. The invented preparation process is characterized in that alkaline solutions of metal metallates are adjusted by their treatment with COi2 to pH value ranging from 5 to 9. So adjusted solutions are then supplied to an ion exchanger in carbonate form, whereby an ion exchanger with metallate anion is formed besides the alkaline carbonate solution. Subsequently alkalis are completely washed out of the ion exchanger and then the ion exchanger is eluated by making use of ammonia aqueous solution, whereby ammonium metallate and anion exchanger in the form of OH are formed, whereupon the anion exchanger is converted by means of Oi2 back to the carbonate form, whereby a solid anion exchanges is used as anion exchanger.
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