Shops and consumers enjoy food and food-based products to have a long shelf life. For this reason, food packaging is often designed with not only plastic for an air-tight enclosre, but also with a layer of aluminum to increase this shelf life. Examples are chips bags and, with cardboard reinforcement, tetra pack to hold fluids.

These packaging materials are a big problem in recycling. The layers are so tightly bonded that they are virtually inseparable, but after they are opened the packaging is usually damaged and unfit for reuse in its then-present shape. Aluminum is a far-from sustainable material, as a lot of electricity is needed to win it from aluminum ore.

An intermediate solution is to stamp tetra packs to form a sort of furniture-construction material, but that does not lead to proper reuse of aluminum, merely not being bothered by it. In addition, it is not the kind of reuse that can go on for ages -- just like we don't need an everlasting supply of park benches from end-of-life plastic, the cycle of such furniture materials will also fill up sooner or later.

In Brazil, the country that is also a bright example of Permaculture, a more fundamental solution appears to have been found. After chopping and soaking tetra-packs, it is possible to remove the paper fraction and be left with the plastic/aluminum combination. The paper is used to improve the quality of recycled paper, as Tetra uses non-recycled paper. The combined layers of plastic and aluminum is led through a plasma reactor (sort of like an extremely hot flame) which melts the aluminum and evaporates or burns the plastic. The aluminum is captured for reuse, while the plastic settles as paraffine, which can be put to good use as well.

GroenGemak is unaware of the amount of energy needed for this process, and if it is efficient. The big gain is that a process is found that actually makes the split. Possibly the producer and recycler can now sit together and work towars a better integration of their processes, and come to a real cyclical process -- which is just the point of recycling.

Source: http://www.alcoa.com/global/en/about_alcoa/sustainability/case_studies/2004/tetra_pak.asp