Regenerating aqueous etching baths containing metal ions

摘要

Regenerating aqueous etching baths containing metal ions, consumed and optionally non-used oxidant and optionally further components comprises: (a) feeding the bath into the cathode chamber of one or more electrodialysis cells to which is applied a potential difference and whose anode chamber is separated from the cathode chamber by an anion exchange membrane; (b) cathodically reducing non-used oxidant and metal ions in the cathode chamber; (c) transferring anions from the cathode chamber via the exchange membrane by electrodialysis; (d) transferring the content of the cathode chamber enriched in metal ions into the anode chamber; and (e) anodically oxidising consumed oxidant in the anode chamber. The apparatus for carrying out the process is also claimed.