METHOD AND DEVICE FOR REGULATING THE CONCENTRATION OF SUBSTANCES IN ELECTROLYTES

摘要

The invention relates to a method and device for regulating the concentration of metal ions in electrolytic fluid for depositing metal using insoluble anodes. Said electrolytic metal also contains compounds of an electrochemically reversible redox system. Metal is dissolved with its oxidized form in an ion generator (1) which is cross-flown by said fluid in such a way that the compounds are reduced. The dissolved metal ions reduced on the items to be treated in order to deposit metal. The compounds of the redox system are re-oxidized in their reduced form on the insoluble anodes in the electroplating plant (13). In order to keep the concentration of metal ions constant in the electrolytic fluid, at least one part of the electrolytic fluid contained in the electroplating plant is conducted through one or several auxiliary electrolysis cells (6) with at least one insoluble anode (8) and at least one cathode (7) and a sufficiently high electric current flow is regulated between the anodes and cathodes pertaining to the auxiliary cells so that the current density on the surface of the anodes is at least 6 A/dm2 and the current density on the surface of the cathodes is at most 3 A/dm2. The ratio between the surface of the anodes and the surface of the cathodes pertaining to the auxiliary cells is thus regulated to at least 1:4.