REGENERATION OF SPENT ETCHANT

摘要

1390268 Recovery of copper from etching solutions SHIPLEY CO Inc 11 Oct 1972 [12 Oct 1971] 46794/72 Heading C7B Copper metal is recovered from an aqueous etching solution containing cupric ions by electrolyzing the solution while cooling the cathode and avoiding solution agitation to decrease the etching potential of the solution. In the apparatus shown the solution is contained in a double-walled tomb 1, e.g. of polyethylene, and is electrolysed between anodes 7 of graphite and stainless steel cathode 2. Cooling water is passed through the cathode from pipe 3 and may optionally be then passed through the jacket 5 of the container. The maximum temperature of the etchant solution is preferably 140‹F. while the temperature at cathode-solution interface does not exceed 90‹F. A loose, granular layer of copper forms on the cathode and is readily scraped off to be removed through outlet 16. After a part, preferably not over 80% of the copper has been removed from the solution, the compo- sition of the solution is adjusted e.g. by addition of ammonium chloride and monoethanolamine and returned to the etching process for re-use.