Take a look around you. Practically everything that you see which is man-made can be recycled. From the wooden table you’re sitting at, the fabric of the clothes you’re wearing, the battery in your mobile phone, the components of your computer and even the materials that make up the building around you.
But not everything is recycled – why is that?
What can and can’t be recycled is quite an expansive question but for domestic purposes, it depends very much on the recycling facilities available to your local authorities. Materials like paper and plastics – as long as they aren’t too contaminated – can be processed and baled into a raw material ready for reuse.
Metals – especially more valuable ones like lead, copper and aluminium – are highly sought after. All these materials have unique recycling processes that have been an established part of manufacturing for over a century, with scrap metal merchants and salvage yards forming a significant industry all of their own.
Many scrap electronics can be stripped down to make new products too. Car parts can be salvaged and gold can even be extracted from computer chips. For some materials, such as mercury, heavy metals like lithium and electrolytes in batteries, recycling might not make financial sense, but because of their toxic nature, recycling them is a legal requirement.
In this article, We checks out the specialised machinery and processes that take our daily refuse and turns it back into products that we can use again and again.
Aluminium in particular is highly sought after as a scrap metal. Because it is both lightweight and strong, it’s used everywhere from drinks cans to aeroplanes. Extracting aluminium from its ore, bauxite, is relatively expensive, but salvaging it from scrap uses just five per cent of the energy needed to make new aluminium.
Like plastic bottles, a large percentage of recycled aluminium comes from beverage containers. The process is similar to plastics too. Once collected, they’re separated from the other metals by an eddy current separator that splits the non-ferrous aluminium with a powerful magnet. The aluminium is shredded into pieces of uniform size, mechanically cleaned then pressed into blocks to minimise oxidation. The blocks are loaded into a furnace and heated to around 750 degrees Celsius (1,380 degrees Fahrenheit), at which point it becomes molten. The melted-down aluminium produces a surface scum known in the industry as dross, which is removed, before high-purity aluminium is added to bring the molten aluminium up to the required grade. The furnace is then rolled onto its side and the liquid aluminium poured out. The end product is either atomized aluminium powder or ingots. Because aluminium isn’t transmuted by this process, it’s just as good as the new stuff and can be recycled indefinitely.
Glass recycling is an old industry that has evolved over decades. A large proportion of glass still makes up household and industrial waste, most of it bottles and glassware. Glass from bottle banks and household recycling is collected and taken to a cullet processing plant. Manual sorting separates metal and plastic contaminants as well as the various glass colours: chemicals used for different
coloured glass can’t be removed. The glass is washed and often passed through a ferrous metal removal machine to capture any metal contaminants that could damage machinery and taint the quality of the final product. The glass is next passed through a belt crusher that pulverises it to a uniform grade. The material is now known as cullet and is ready to be made into new products.
What happens to my drinks bottle?
Recyclable waste – We use around 20 times more plastic than we did 50 years ago. Currently about a third of the plastic bottles we chuck are recycled.
Collection – It can cost anything from GBP 60-130 (USD 95-210) per ton for authorities to collect recyclable waste.
Sorting – A reclamation yard, or materials recovery facility (MRF), will sort the plastics from other recyclables for around GBP 25 (USD 40) per ton.
Bale sale – Balers squash plastic bottles and turn them into cubes that can be sold to reprocessing plants for up to GBP 280 (USD 450) a ton.
Reprocessing – The reprocessing plants sort the plastics according to the various types. It then washes and chips the plastic into flakes or pellets.
New products – The recycled plastic is heated and remoulded in order to make new products, like clothing.