Copper recovery from spent ammoniacal etching solutions

摘要

The present work aims at studying the electrolytic recovery of copper from the spent ammoniacal etching effluent of the printed circuit board production. The investigated spent ammoniacal etching effluent is an alkaline solution with total ammonia concentration of 9.5 M, copper concentration higher than 140g/l, and chloride concentration varying from 175 to 190 g/l. A prc-trcatmcnt of this effluent with a strong basic anionic exchange resin in order to reduce the high chloride concentration to low level, allowing copper clcctrowinning without any corrosion problems created due to anodic oxidation of chloride ions, is examined. Moreover, the effect of operating parameters during copper electrowinning, including electrode arrangement, intcr-clcctrodc distance, electrolyte agitation rate, current density, etc. on current efficiency and copper recovery are investigated. The results are used to determine the optimum conditions for economically feasible copper electrolytic recovery from the spent ammoniacal etching solutions.