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What metals can be recycled?

In short, almost all metals can. For example in the U.S., of the 132 million tonnes of metal ‘apparent’ supply, recycling contributed 67 million tonnes.  That’s equivalent to about 50.8% [1]. In the UK, iron and steel make up the majority of the recycled metal in use. It is supplied mainly from industry and increasingly from municipal and household waste. Common examples include aluminium and tin/steel cans, and cars.


UK metals recycling statistics UK metals recycling statistics [2].

However, the process of metal recycling is not as simple as ‘melt it’, materials science knowledge is needed. There are two viewpoints to the recycling process, the recycling of individual metals, and the recycling of whole products.

 

Is recycling economically feasible?

Recycling is a great idea, in theory.  The sad fact is that unless there are clear economic gains from recycling metal, large-scale initiatives are unlikely to become popular.  To be economically viable, the energy saved by recycling needs to be significantly larger than the energy needed to produce the metals from ores.

There are statistics quoted for the amount of energy saved by recycling, for example these from the British Metals Recycling Association [2]:

Metal
Energy Saving (%)
Steel
62 - 74
Copper
87
Zinc
63
Lead
60

But, where do these numbers come from?

It is the job of the materials scientist to come up with values like the ones above, requiring calculation as precisely as possible using fundamental background knowledge. 

An example of how this is done – for Aluminium.

 


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