Apparatus and method for purifying bath liquids

A method for purifying bath liquids of different kinds used for cleaning metal surfaces by separating metal cations dissolved in the bath liquids, said method comprising:

• circulating metal ion-containing bath liquids through a plurality of electrolytic cells, each composed of an anode compartment and a cathode compartment separated by one or more ion-selective permeable diaphragms, in such a way as to introduce the bath liquid into said anode compartment or an intermediate compartment defined between the diaphragms;
• electrophoresing metal ions contained in the bath liquid into said cathode compartment through the permeable diaphragm;
• circulating a common catholyte into each of said cathode compartments of the electrolytic cells, thereby forming metal particles in the catholyte by way of coagulating magnetic metal particles and non-magnetic metal particles together;
• and
• separating the coagulated metal particles from the catholyte by a magnetic separator.

A method for purifying a bath liquid used for cleaning metal surfaces by separating metal cations dissolved in the bath liquid, said method comprising:

• circulating a metal ion-containing bath liquid used for metal surface cleaning through an electrolytic cell comprising an anode compartment and a cathode compartment separated by one or more ion-selective permeable diaphragms, in such a way as to introduce the bath liquid into said anode compartment or an intermediate compartment defined between the diaphragms;
• electrophoresing metal ions contained in the bath liquid into said cathode compartment through the permeable diaphragm;
• circulating a catholyte through said cathode compartment in such a way as to introduce magnetic metal particles into the catholyte, thereby coagulating the magnetic metal particles together with the non-magnetic metal particles which have been electrophoresed into said cathode compartment;
• and
• separating the coagulated metal particles from the catholyte by a magnetic separator.