How is metal recycled?
Metals have been recycled since at least 4000 BC, when bronze and iron were forged into tools and weapons. It’s thought that early man used gold even earlier, from around 40,000 BC.
Today, metals are still commonly and easily recycled. Iron and steel are the most recycled materials in the world, with the aluminium can being the single most recycled container. Compared to plastics, metals are surprising easy to recycle, and it is more cost-efficient than mining and processing new ore. Metals can also be recycled repeatedly without altering their properties, which makes them highly valuable both in monetary terms and for the environment. Non-ferrous metals include copper, aluminium and nickel, but also precious metals such as gold and platinum, and are more valuable by weight than ferrous metals.
But back to the question – how is metal recycled? The metal recycling process has seven stages:
1 – Collection
Because metals are commonly recycled and have a higher value than other materials, they are more likely to be sold for scrap than other products that get sent to landfill. Most sources are from vehicles and household equipment but other sources include ships, farm equipment and large structures.
2 – Sorting
This involves separating metals from other waste, sorting it into ferrous and non-ferrous metals and ultimately into the type of metal (aluminium, brass, copper, lead, etc.). Magnets are used for iron-containing ferrous metals and, along with sensors, are used in automated recycling facilities. Individuals may also use a magnet, or will be able to recognise the type by the colour and weight. Metal is more valuable if it is clean.
3 – Processing
Metals are then shredded to allow further processing and to facilitate the melting process – it takes up less energy. Aluminium is made into small sheets, and steel into blocks.
4 – Melting
Different metals are melted in specific furnaces designed for that particular type. This is probably the most energy-intensive part of the process and can take from a few minutes to several hours.
5 – Purification
The metal is then purified to rid it of contaminants and ensure the quality of the final product.
6 – Solidifying
The molten metals are then cooled and solidified. This process forms them into shapes – such as bars – to be used in the manufacture of new products.
7 – Transportation
Once cooled and shaped, the metals are transported to factories to be used as raw material. And once the product reaches the end of its life, the process begins all over again.
Although it’s an easy and valuable process, the current recycling rate is not as high at is should or could be. Community awareness can help rectify this. While most councils accept metal cans and tins in home recycling bins, larger household items can be taken to your local scrap dealer.