FIELD: printing equipment.
SUBSTANCE: invention can be used in production of printed circuit boards. For regeneration of hydrochloric copper-chloride solution of copper etching, ions of bivalent copper are reduced with hydrazine to univalent copper ions in one of two pre-calculated parts of total volume of etching solution of copper. Univalent copper ions are then precipitated by adding a thiocyanate salt or ammonium iodide salt. Precipitated residue of the univalent copper compound is separated from the solution. After the residue is separated, the solution purified from copper ions is mixed with the second part of the total volume of the copper etching solution which has not been treated with hydrazine and thiocyanate or ammonium iodide. Solution thus obtained, which contains copper ions in a concentration corresponding to the nominal range of values for the fresh copper etching solution, is subjected to aeration with air oxygen for oxidation of possible hydrazine residues and univalent copper ions. After aeration copper etching solution is ready for reuse.
EFFECT: invention enables regeneration of copper chloride hydrochloride solution of copper etching without considerable increase of initial solution volume and introduction of undesirable admixtures into the solution, and provides high rate of regeneration.
4 cl, 2 ex
