The process of sorption-electrochemical cleaning of rinse waters, obtained after ammonia etching of printed circuit boards from copper ions, is proposed. Cation exchanger KU-2×8 and ampholyte Lewatit MonoPlus TP 207 for the extraction of copper were tested. Capacity up to breakthrough of Lewatit MonoPlus TP 207 is 0.11 g/g and a full dynamic exchange capacity for copper of 0.15 g/g. Various options of a pregnant ion exchanger desorption are considered. The best stripping ability has a 20% solution of sulfuric acid. The possibility of desorption by a partially de-coppered eluate was studied. This scheme allows the use of acid formed in the process of copper electro-winning. The effect of concentrations of NH4Cl and NH4OH on the sorption of copper was studied. It was shown that, with an increase in the concentration of NH4Cl to 100 g/dm3, the capacity of the ion exchanger decreases by 10.42%. Thus, the ion exchanger Lewatit MonoPlus TP 207 effectively absorbs copper even at high salt background. A combined sorption-electrochemical technology has been proposed for treatment of rinse waters. The proposed technology will reduce consumption of fresh water and ammonia for printed circuit boards washing and extract copper in the form of elemental metal.

The process of copper regeneration from spent hydrochloric acid etching solution of printed circuit boards is considered. A combined scheme is proposed, which includes the preliminary removal of excess chlorine ions from the solution, using a highly basic anion exchange resin and the subsequent electrochemical precipitation of copper. A solution contents, g/dm3: 237 Cu, 27 NH4Cl, 11.6 HCl was used. Electrical extraction was performed at a current density of 650 A/m2. The method makes it possible to prevent the emission of chlorine at the anode and ensures the obtaining copper as metal.

No abstract