We have heard many times; aluminium recycling is really a sustainable process with low environmental impact. Why? Obtaining aluminium from the recycling of exhausted objects allows an energy saving of 95% compared to the production from raw materials, in other words the energy used by the recycling industry is 5% compared to that required for the extraction and production process, which starts with bauxite.
This is because the bauxite mines, the mineral with the highest concentration of aluminium, are generally below ground level and are often found in isolated locations far away from where bauxite is then processed. On the contrary, the aluminium recycling process uses only 5 percent of the total energy used for the production of primary aluminium from the mines, thus reducing environmental and economic costs.
In the recycling economy the role of aluminium is really fundamental, in environmental terms and also in industrial sustainability. It is a light and ductile metal, which is why it is used in many industries.
In fact, recycling aluminium has a low energy cost and consequently a low environmental impact. It is estimated that 14 kWh is needed to obtain 1kg of aluminium from bauxite, while only 0.7 kWh of energy is needed to obtain 1kg of new aluminium from the exhausted and disposed. Really a considerable saving in terms of energy.
Recycled aluminium is used in many industries, starting from the automotive one. Almost all of the aluminium used for the production of tire rims comes from recycled raw materials, as well as 30% of which is used for the production of pistons and cylinders, or 40% of which is used in the structure overall of cars.
But how does this aluminium journey, from our garbage to new life, take place? Aluminium recovered from industrial waste or other sources of separate collection is taken over by specialized plants where separation and initial treatment takes place.
Are you wondering what kind of aluminum can be considered recyclable? First make sure you fully understand the legislation of your municipality that will tell you where and how to recycle aluminium.
However, some general rules can always be useful, as well explained by CiAl (National Aluminium Packaging Consortium): the following ones are all aluminium objects and therefore can be disposed in the separate waste collection container:
- collapsible tubes (without closure cap);
- beverage cans;
- trays and cans in which are sold meat or fish,
- pet food;
- spray cans (taking care to remove the plastic cap while leaving the dispenser instead);
- the trays for cooking and storing food.
But we can also recycle:
- Also the aluminium foil (both the so-called tinfoil, and the sheets that wrap for example the chocolate bars);
- screw caps of water bottles, fruit juices, oil or liqueurs;
- the protective capsules to close the bottles (such as those that wrap the spumante cork);
- various lids or closures (such as the lid of the yogurt or coffee capsules).
It is not necessary to wash the containers, the only care is to remove any food or other product residues, which is extremely easy for liquids and for the contents of the tubes, which can be squeezed to the last drop.
First step in the recycling process involves the separation of aluminium from any other metallic or different material through a magnetic separator.
The aluminium thus obtained is compressed in the form of bales, ready to be subjected to a quality control and then to a first treatment in the foundry at a temperature of about 500 °, a lower limit than the melting point of the aluminium, so that traces of adherent substances or paints are removed.
This process takes place in highly technological plants, where the highest quality and safety standards are respected in terms of air emissions and compliance with environmental regulations.
Most organic substances that can be present as oily emulsions or food residues are eliminated through a process of thermal oxidation and drying. The whole process of “purification” of aluminium waste takes place with no need for any chemical treatment or pollutants.
The last step useful for recycling aluminium is the fusion that takes place at a temperature of 800° C. Now we have a casting of liquid molten aluminium that is transformed into bars, ready to re-enter the industrial production process, and be used for the intended uses regulated by Italian and European legislation.
This recycling process seems like a journey into an alchemical laboratory, where, as a magic, a precious material can reborn from garbage, ready to “revive” and become new objects.
If the world of aluminium also fascinates you, we suggest you follow the news of CiAL – National Aluminum Packaging Consortium, available on the official website both in Italian and in English.