The production of printed circuit boards using the printing process produces considerable quantities of copper-containing etching solutions. The copper is recovered from the ammoniacal etching baths by cementation with aluminum waste at >= 99 % Cu yield rates. Instead of the usual landfilling, the aluminum-containing solution is processed into a coagulant which can be used in the treatment of mining tailings and wastewater. The aluminum oxychloride produced in this way was characterized in detail and its effectiveness as a flocculant for a finely dispersed system (kaolin suspension) was investigated and confirmed in a jar test.