Process for producing pure ammonium metallates
AssigneeH.C. Starck GmbH
InventorsWilfried Gutknecht, Wolfgang Mathy
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Abstract
The present invention relates to a process for the production of pure ammonium metallates of the metals W, Mo, V, Cr and Re, wherein alkaline metal salt solutions are adjusted to a pH value in the range from 5 to 9 by reaction with CO.sub.2, these metal salt solutions are passed through an anion exchanger in carbonate form, wherein, in addition to the alkali metal carbonate solution, the metallate form of the ion exchanger is formed, the ion exchanger is then washed until free of alkali and is then eluted by means of aqueous ammonia to form ammonium metallate solutions and the anion exchanger in the OH form, wherein the anion exchanger is converted into the carbonate form by means of CO.sub.2 treatment and is recycled.
Claims10
Process for production of pure ammonium metallates of a metal selected from the group consisting of W, Mo, V, Cr and Re, comprising the steps of:
- (a) providing an alkaline metal salt solution of the metal,
- (b) reacting the solution with CO.sub.2 to adjust the pH of the solution within a range of 5 to 9,
- (c) contacting the pH adjusted solution with a carbonate form solid anion exchange material to produce a metallate form of the anion exchange material and an alkaline metal carbonate solution,
- (d) eluting the metallate form of the anion exchange material with aqueous ammonia to form (i) an ammonium metallate solution and (ii) an OH form of the anion exchange material,
- (e) separating the thus formed ammonium metallate solution and OH form anion exchange material and treating the OH form anion exchange material with CO.sub.2 to convert it to a carbonate form and recycling the carbonate form anion exchange material to step (c) for use as the carbonate form solid anion exchange material of step (c).
Dependencies are inferred from the claim text.