process for production of pure wolframsaeure and / or molybdaensaeure (wasserloesliche isopolysaeuren), with, in particular, silicon, phosphorus, arsenionen etc. polluted alkaline tungsten and / or molybdaen - metallic salt solutions.

摘要

In this process, the contaminated solution is acidified, the resulting precipitate is filtered off, and tungstic and/or molybdic acid are prepared from the pure solution by electrodialysis, in which the pH necessary for precipitating the ions to be hydrolysed is established by admixing tungstic and/or molybdic acid freed from alkali metal ions by means of cation exchange/electrodialysis, a portion of the tungstic and/or molybdic acid recovered after electrodialysis being used again in the purification process.