Tim Can's Story of Metals Recycling
Next time you have an empty drinks can to throw in the bin, stop a moment and look at the can. It's been made so that the drink gets to you safely and remains full of fizz until you lift that ring on the top. Then, when you've drained every drop, the can has done its job and you just throw it in the bin. That seems a sad end to a can that has been useful but it could go on being useful - in a different way.
If you look very closely at your can, you will probably find that it has a shape printed on the side, made up of arrows chasing each other, perhaps like one shown on this page. This is to tell you the can may be recycled. That means instead of being thrown away and wasted, it is possible to make a new can, or even something quite different that is also made from metal.
Your can will go to a metals recycling factory where it is chopped up with many, many other cans into small pieces which will then be melted in a furnace, so that instead of being hard and solid it becomes an extremely hot liquid.
Once this molten metal is poured out of the furnace it begins to cool, and gradually becomes solid again. Now it can be put into a machine that rolls it out very thinly, rather like pastry, so that lots more new cans may be made from it.
If recycling wasn't done, new cans would have to be made entirely of metal produced from metal-bearing rock called ore extracted from mines, probably in a country far away from ours.
To turn that ore into metal would involve carrying it across the sea to factories where it would have to go through many processes before it even looked like metal.
Recycling means that less ore has to be mined.
That is important for the people who will live in the future, because once all the metal ores in the ground have been used up, there won't be any more. There are still enough ores to last for a long time, but of course it is up to us to use them properly. That means not wasting metals, but recycling them.
One of the interesting things about metals is that you can go on using them again and again and again, simply by melting them down and making new things from them. In fact we can go on doing that for ever - which makes it even more important to see that drinks cans and other metal products are recycled and not just thrown away.
Your drinks can has almost certainly been made with at least some recycled metal, which shows that recycling is going on already. In fact it has been going on for a very long time, and is not just about drinks cans.
Things made from metal
How many things can you think of that are made from metal? Try writing a list of just five. One could be a saucepan, another a bike. Then you might think of knives, forks and spoons. It could be something as small as a paper-clip or as big as a ship. There's the cooker in your kitchen, a washing machine or a refrigerator. A motor car or a lorry, an aeroplane, a train - and the rails that the train runs on.
That's a good many more than five, and you will probably have thought of lots of others. They are all made from metal and they can all be recycled.
We can talk about things being made from "metal", but in fact they are made from different sorts of metal. Some of the most common are steel, copper, aluminium, zinc, tin and lead. Then there are mixtures of metals called alloys which have been made to do things that separate metals can't do as well.
Some drinks cans are made from steel - in itself a very pure form of iron - and others from aluminium. Sometimes the printing on the side will tell you. There may be the letters ALU inside a chasing-arrows shape, and that is short for aluminium. It is important to know the difference, because - yes, you've guessed it - steel cans are recycled back into steel and aluminium cans are recycled back into aluminium.
Although both these metals are used to make cans, they are used for a great many other things as well, and can't be mixed.
What a magnet can tell you
The easiest way to sort steel from aluminium cans is with a magnet. In fact you may find a magnet symbol printed on the side of some steel cans.
Experiment for yourself. Collect several cans and touch each of them with a magnet. There will be no effect at all with those made from aluminium but the magnet will feel almost as though it is sticking to those made from steel. That is because anything iron, and therefore steel, is magnetic. Aluminium is non-magnetic.
There are other differences between metals as you will see on the next page.
If you left an empty steel can in the open for a few months, it would go rusty. So it is easy to prove that steel will rust. In fact the steel can is coated inside and out with a very, very thin layer of tin - so little that you might hardly believe it was there. Yet there is enough to help to preserve whatever is in the can - provided it isn't left out in all weathers for a long time.
People often talk about "tin cans", although they are not really made of that at all. If they were made of tin they would be so expensive that you wouldn't be able to afford to buy anything packed in them, because tin is a very much more valuable metal than steel. So we have learned to use it in very small quantities. Even so, the thin layer of tin on a can is still recyclable.
It is possible to stop steel rusting by adding one or two other metals such as nickel and chromium, so making one of those alloys, or mixtures of metals.
The result is called stainless steel, which is too costly for cans but is very often used to make knives, forks and spoons, and perhaps the sink in your kitchen at home. In fact, in places where we want to keep things particularly clean and shiny.
You can see from the examples so far that different metals are useful in different ways, and so they are often used together in making things. As many as ten or twelve metals and alloys may be used in one car, but as we have already seen, metals must be separated if they are to be recycled successfully.
To do this, the metals recycling industry uses very big machines - often bigger than a whole house. Worn-out cars, refrigerators, washing machines, cookers and other familiar products that have come to the end of their useful life are fed in at one end, and are chewed up inside the machine into clean pieces of metal each about the size of your two fists put together.
The iron and steel are removed by special magnets, leaving a mixture of other metals like copper, aluminium and zinc which are also recycled, as well as dust, dirt and other things that can't be recycled. Each of those metals is separated and sold to a company that melts it - so beginning the journey of manufacturing back to a new car or washing machine that, ultimately, will be recycled again.
Things are made, they are used or become worn-out, and then they are recycled. It's so much more sensible than throwing them away, don't you think? And much better for our world because we don't have to dig so much ore out of the ground.