This is an English translation of the German article Aluminiumrecycling.
Why is aluminum recycling so important?
aluminum (or aluminium) is occurring on the earth surface in chemically bound forms and it is the third most frequent element in the crust of the earth, after oxygen and silicon. So other than the lanthanides it is not really rare. Aluminum ore can be found in large quantities and they are relatively cheap. Many minerals could be used, but bauxite is what is really used for obtaining metallic aluminum. The process of obtaining aluminum from bauxite is really expensive. Aluminum is very reactive and a lot of Energy is needed to gain it. Purely chemical and thermal processes do not work or are not competitive. Current aluminum production work with Electrolysis. Using electrolysis with an aluminum salt dissolved in water would yield hydrogen, so it is necessary to do it with molten salt. First Bauxite contains chemical compounds and salts of aluminum, silicon and iron, which are separated and split to obtain aluminum hydroxide, which is heated to gain aluminum oxide. This is molten and put into the oven. Which contains a cathode of graphite on the ground, near which liquid aluminum is collected. The Anode consists also of graphite and oxygen is gained there, which slowly burns the anode, so it has to be replaced frequently. The heat of this process is sufficient to keep the aluminum oxide liquid, once the process has been started. So the production of aluminum from bauxite uses much higher magnitudes of the energy then the process of aluminum recycling. Even the burning of aluminum that is thrown into the regular garbage does not even nearly compensate for the energy usage in the aluminum plant, considering the whole process and the fact that thermal power plants have a limited efficiency due to thermodynamic principles.
In the old days the problem could be solved by simply transporting bauxite to countries like Norway and Iceland, where water power is available in large quantities. These days powerful electrical power transmissions exist from Norway to Central Europe. So Norway can now sell electricity to other parts of Europe and contribute to reducing the usage of German coal power plants. Electricity in Norway has become more expensive and Norwegian aluminum plants have a harder time then some years ago.
In short, recycling of aluminum is a good thing for the environment. So I recommend that you think about it and try to take it serious, if there is a way to deliver aluminum separate from your garbage.
