Aluminium is the centrepiece of modern recycling. Its reuse requires just 5% of the energy used to make new stocks, leading to major reduction in carbon emissions. In this blog post, we’ll cover some of the ways how aluminium is recycled from scrap metal, and which countries do it most efficiently.
The History of Aluminium Recycling
The metal industry as a whole has been one of the greatest innovators in recycling and sustainability. Most of the major manufacturers understand resources are limited, and so there have been major efforts since the 1900’s to find the best and most cost-effective methods of extracting old material. Aluminium recycling initially became quite popular during World War II, although this wasn’t a new practice. It was only in the 1960’s, when aluminium beverage cans exploded onto the market, that recycling the non-ferrous metal became such a standard practice.
Which country recycles the most aluminium?
Brazil has been the leading country worldwide in collecting aluminium cans for recycling since the early 2000’s. This is down to a number of factors, such as the fact it already had an established recycling market in all of its regions, with ease of collection, transportation and marketing - the high value of aluminium scrap doesn’t hurt either!
How Aluminium is Recycled from Scrap Metal
When aluminium is recycled from cans, utensils or solid parts, it first has to be sorted from other scrap metal. Since it is non-ferrous, it is less magnetic than, say, iron, and is thus ejected using an ‘eddy-current’ separator. These devices use a rapidly revolving magnetic rotor in a cylindrical drum. It creates a secondary magnetic field around the cans, which actually propels them from the other waste materials.
After this, a re-melt process is used to separate the aluminium from the inks and coatings - the kind you might see on a drinks can. Ingots are produced from the melted aluminium, which are sent to mills where they are rolled out, giving the recycled aluminium greater flexibility and strength. In this stage, it can be re-purposed into all manner of useful shapes and products.
But what about when aluminium is used mere as a component, not as the sole material? Most of us are oblivious to the precious metal lying in old, unused electronics. For example, laptops, phones, cameras and other devices use gold to connect their components, in such small flake-like quantities, you can extract them with something as simple as a coffee filter! Aluminium is rather different. For example, CPUs today have integral aluminium heatsinks, and are built on their own printed circuit board.
There are numerous methods for separating partial quantities of aluminium from other metals, including municipal incineration (where electronic waste is incinerated, diluting the metal) and bioleaching (the process of using bacteria and fungi to separate metals from electronic waste). Some options, like pyrometallurgical recovery, aren’t able to deal with aluminium due to its non-ferrous makeup.