Novelis is the world’s largest recycler of used beverage cans. They arrive at its factory in Warrington, England from all over the world. Compressed into bails, each weighing up to 1,000 kilograms and containing as many as 65,000 aluminum cans. Every year we save enough energy recycling aluminum cans, cars, tools, even planes, to run the whole of India. The bales of compressed cans are loaded onto a conveyor and fed into a 340 horsepower shredder. Aluminum is tricky to sort because unlike some metals, it can’t be separated out with a magnet.
So next, the shredded scrap passes through an optical sorter at a rate of three meters per second. The machine uses infrared sensors to sort out what’s metal and what isn’t. Then blasts away any plastic or glass with jets of air. A powerful magnet sucks up any scraps of steel, leaving just aluminum. We Brits say aluminum. And the Americans say aluminum. But who’s right? Well, Sir Humphrey Davey, the British guy who discovered it in 1807, he wrote down the name as aluminum, which no one calls it. Then he changed it to aluminum, and he changed it again to aluminum. So, either he didn’t know what to call it or he just couldn’t spell. It’s aluminum. Aluminum. The next problem is, aluminum doesn’t melt until 660 degrees. The paint and lacquer aren’t so lucky. They’re instantly vaporized. The clean aluminum chips are ready for the next stage, melting. Two furnaces hit a blistering 730 degrees. And handle up to 100 tons of aluminum each. The trouble is, when the aluminum melts, it reacts with air forming a layer of aluminum oxide that floats on top. This unwanted oxide is known as dross.
A brave furnace operator skims it off with a giant, steel spatula. And the alloy is ready for the casting area. The only problem is getting there. A river of molten metal flows downhill to a holding furnace that’s the size of a double-decker bus. Somehow, they need to pour the liquid metal into a mold. Remarkably, the solution is to tip the entire furnace. And a fountain of deadly metal pours into one of three molds set ten meters into the ground. Inside, they will be cast into three towering blocks of aluminum. After two and a half hours they have three giant aluminum monoliths, called ingots.
Each one is ten meters long, weighs 27 tons and is made up of million recycled cans. Aluminum, or aluminum, is not expensive because it’s rare. In fact, it’s the most common metal in the Earth’s crust. It’s expensive because it’s so hard to extract from the rock around it. 150 years ago, it was more expensive than gold. Today, demand for aluminum is so high the ingots don’t lie around. Their transformation back into cans starts with a 900-kilometer journey to a rolling mill in Germany. Here, they’re heated in another furnace to 525 degrees. This relaxes the bonds between the aluminum atoms, releasing any stresses within the ingot. Then it’s passed back and forth through a series of rollers. It’s a bit like rolling pastry. Each set of rollers thins out the metal until it’s a quarter of a millimeter thick and 10,000 meters long.
That’s 1,000 times its original length. Massive reels of the aluminum arrive back in the UK at Ball Packaging to undergo reconversion into cans and possibly something a little more out of this world. We’ve got three basic product categories, beverage packaging, household metal packaging, and we also have an aerospace division. So, the interesting thing, of course, is manufacturing beverage cans is rocket science. The aluminum alloys for rockets are very similar to the ones used for cans. So theoretically, your old can could be on its way to space.
Meanwhile, on planet Earth, they feed the sheets of aluminum into a rapid-fire cupping press. This heavyweight knocks out thousands of shallow cups. The secret of turning them into cans is a tight squeeze. Every cup is rammed through a series of rings, each narrower than the last. Forcing the aluminum through the rings squeezes it into a cylinder and a new can is born.
The very first time anyone put a beverage in an aluminum can it was beer, it was in the US, and it was 1959. And even back then, they still recycled, you got a cent for every can you brought back. They produce around 6 and a half million cans here every day and send them all over the world. That’s a whole lot of aluminum. Luckily, there’s plenty more where these came from.