REAGENT METHOD FOR REGENERATION OF COPPER-AMMONIA SOLUTION OF COPPER ETCHING Russian patent published in 2019 - IPC C23F1/46 C23G1/36 

FIELD: chemistry.

SUBSTANCE: one pre-calculated part of total volume of spent solution of etching of copper subject to regeneration is mixed with solution of hydrazine for reduction of ions of mono- and bivalent copper to metal copper, sediment of which is separated by decantation or filtration. Process of reducing divalent copper ions can be limited by obtaining univalent copper ions, which are precipitated by adding ammonium salts to the solution, and the precipitated residue of the univalent copper compound is separated from the solution. After separating copper precipitate or univalent copper compound, volume of etching solution of copper, which has been treated with hydrazine, is mixed with another pre-calculated part of total volume of spent solution of etching copper, which is not treated with solution of hydrazine. After mixing, obtained solution is subjected to aeration with air oxygen. After aeration copper-ammonium-chloride or copper-ammonium-sulphate solution of copper etching is ready for repeated use.

EFFECT: invention relates to a method of regenerating a copper-ammonium-chloride or copper-ammonium-sulphate solution of etching copper using hydrazine or an aqueous solution of hydrazine with concentration of 1–99 % by weight.

3 cl, 2 ex