How is Aluminium Recycled?
Why is Aluminium Recycled?
Aluminium has been recycled for almost 100 years and a striking 75% of all the metal ever produced is still in use today. Since recycled aluminium has the same characteristics of new as well as taking only 5% of the energy to make, it commands a high value as scrap or on the secondary market.
Aluminium is the most frequently recycled metal. It is extremely versatile and can be used (and reused) in a variety of different products such as cans, window frames, food packaging, cars, etc.
Aluminium is not only highly flexible but also very lightweight. It is extremely strong when combined with metals like copper, magnesium, silicon, and molybdenum. It also has high thermal conductivity, is non-magnetic, and is extremely resistant to corrosion. Aluminium can be easily machined, cast, bent, alloyed, tapered, welded, and it does not degrade with consistent reuse.
This is the reason aluminium is used extensively in manufacturing, construction, and consumer products industries, making products small and large.
If you have a look, you will notice that aluminium is around you all the time. Additionally, while other metals have become obsolete, this metal has retained its usefulness and value over time.
How is Aluminium Recycled?
Step 1- Collection
Foil trays, drink cans, and aerosols are usually collected from homes or can-banks. Foil is collected separately under some recycling schemes.
Step 2- Sorting
The recyclable material that is collected is taken to a local materials recovery facility or waste transfer station where it is sorted. Magnets may be employed to separate metals. This leaves aluminium behind because it is non-magnetic. Some food and drink cans are made out of steel so sorting is an important process.
Step 3- Shredding
Block bales of aluminium are transported to a processing plant. The blocks are then laid onto a conveyor, which takes them to a shredder. The shredder cuts the cans into small pieces. This is done to make it simpler to get rid of all the coatings and paints that are used for protection and decoration purposes.
Moreover, it makes it easier for aluminium to melt quickly in the furnace. Once again, a magnet is put over the shredded pieces to ensure that there are no steel particles.
Step 4- De-coating
The aluminium shreds are taken by a conveyor system into a specialised decoater. This is where all the decorations are separated from the shredded pieces. The decoater blows very hot air through the micro pieces of shreds and the paintings, coatings, and inks vaporise. Next, the hot gases are removed and the remaining metal is cleaned.
Step 5- Melting
The aluminium is then sent to furnaces with temperatures of 700C, which is the lowest melting point of some metals. During melting, some chemicals are added to the molten aluminium to ensure it possesses the correct composition.
All the impurities float to the surface of the heated aluminium. This forms a layer known as dross, which is then removed using a specialised scraping tool.
Step 6- Moulding
The molten aluminium is sent to the holding furnace, where it is turned into ingots. The holding furnace tilts from time to time to pour the hot molten aluminium into moulds. Each block or inglot contains nearly 1.6 million drink cans.
Step 7- Transportation of the Ingots
An overhead careen then lifts the finished ingots from the casting pit. The blocks are loaded onto a track to be transported and sent out or dispatched to the rolling mill.
Afterwards, the blocks are rolled out into thin sheets of aluminium, which gives the metal greater flexibility and strength. The metal sheets are collected by packaging factories to make foils, drink cans, and other everyday products.
The process then begins again, usually after about six weeks. The recycled aluminium items are sent back to the shelves in the supermarkets and shops for usage.
Advantages of Aluminum Recycling
Used beverage containers are one of the largest components of aluminium scrap. And most scrap aluminium is recycled back into cans, which requires only 5% of the energy of producing new ones from scratch. This results in less greenhouse gas emissions.
Prevents Depletion of Bauxite Ore
Aluminium is mined from Bauxite ore. This, therefore, implies that recycling prevents constant mining and depletion of this valuable commodity. Recycling prevents close to 5% of total Bauxite ore mining worldwide.
Reducing Carbon Footprint
Recycling aluminium helps prevent more than 90,000,000 tons of carbon dioxide from being let free in the atmosphere every year.
Aluminium Never Wears Out
It is an infinitely recyclable metal, which means that it would not lose its natural qualities even after being recycled innumerable times.
Aluminium has other benefits such as satisfying increasing demand, reduction of landfill waste, along with the advantages mentioned previously. Recycling aluminium is, thus, a crucial activity that has become essential for every country to embrace in order to reduce carbon dioxide emissions and save this planet.