METHOD FOR PROCESSING THE SOLUTION FOR ETCHING PRINTED CIRCUIT BOARDS Russian patent published in 2022 - IPC C23F1/46 C23G1/36 B01D61/44 

FIELD: radio electronics.

SUBSTANCE: invention relates to the production of printed circuit boards. A method for processing a PCB etching solution containing 200-250 g/l of ammonium persulfate, 10-20 g/l of sulfuric acid and copper ions is proposed, including electrochemical treatment of the etching solution in a three-chamber electrolyzer with two cation exchange membranes using a stainless steel cathode and a platinum titanium anode, in which the etching solution is located in the middle chamber of the electrolyzer. Electrochemical treatment of the etching solution is carried out simultaneously with the process of etching printed circuit boards in the middle chamber of the three-chamber electrolyzer. After the separation of metallic copper at the cathode, the solution from the cathode chamber of the electrolyzer is moved to the anode chamber for the transfer of copper and ammonium ions through the cation exchange membrane to the middle chamber, the solution in which is corrected by the addition of ammonium persulfate. The process is continued until the concentration of ammonium sulfate in the solution of the middle chamber is 200-250 g/l, after which the etching is suspended, the electrodes are transferred to the middle chamber and electrochemical treatment is continued until the copper is completely extracted from the solution.

EFFECT: service life of the PCB etching solution is increased and the formation of toxic waste is prevented due to the complete extraction of copper ions and the production of end products in the form of pure metallic copper and ammonium sulfate solution, which can be used as fertilizer.

1 cl, 3 ex