Urban Mining: Kupfergewinnung durch Zementation von Composite-Verpackungen und Altbeizsäuren

The process design for resource recovery is presented, in which a waste stream of used pickling acid and of composite packaging is combined. Subsequent processing of secondary raw copper as cementation product conserves resources and saves energy. Packaging for liquid food (TetraPak etc.) and for powder is often built up of composites of paper, polyethylene and aluminium. For wet chemical treatment reject material (mostly paper fibre free, rough shredded) was used, which was examined according to its shredding behaviour. Used pickling acids are known in different compositions. The optimal conditions for the process have been identified within the wet chemical experiments. It was demonstrated that the aluminium oxide layer of the reject material could be depassivated by addition of chlorides. Regarding the reductive chemical reaction of the aluminium oxide layer it could be managed to carry out the wet chemical treatment with preservation of the valuable non-ferrous metals. For the wet chemical treatment, a newly developed combined screening stirred reactor proved particularly effective. The process happens in the reactor itself so that the product of the cementation settles and passes the sieve plate. Copper has been determined in fraction between 474 and 860 g/kg in the cementation product. From other Al-containing packaging (blisters etc.) copper has been obtained success fully in the cementation product, too