Aluminium is one of the most prevalent metals on the planet, making up around 1.59% of the earth and 8% of its core. It is the third most abundant chemical element we have, after only oxygen and silicone. It’s also all around us: drinks cans, kitchen foil, mobile phones and laptops can all be made of aluminium (or aluminum, as it is known is Canada and the US). So, what is it about this metal that makes it so special and so popular? And what else is it used for, apart from wrapping food and holding fizzy drinks?
Let’s start by looking at where aluminium comes from. The main ore (sedimentary rock) in which aluminium can be found is bauxite. It is relatively soft, with a clay-like texture and a reddish hue. It can be found all over the world, particularly in tropical and sub-tropical zones, and some of the earth’s leading locations for bauxite include Australia, China, India, Jamaica and Kazakhstan. Bauxite is named after Baux, the region of France where it was discovered in 1821. The picture below was taken at the site of a former bauxite quarry in Puglia, Italy. It was dug out between 1950 and 1978 and is now part of the Alta Murgia National Park. It’s a popular spot for hiking and photography, thanks the surreal, Bauxite landscapes that remain.
Aluminium is element number 13 on the Periodic Table, and one of the latest metals to be discovered by humans. Long before scientists worked out how to make aluminium, they discovered alum, a chemical compound similar to a salt that contained the metal. In ancient times, it was used extensively, and throughout history alum has been particularly useful in fireproofing and papermaking.
It wasn’t until the early 1800s though, when there were great advances in science, specifically electricity, that aluminium itself was found. In 1808, an English scientist called Humphry Davy worked out that aluminium could be extracted by electrolyte reduction from aluminium oxide. Davy only put the experiment together in theory, however; it was yet to be carried out in practise. Finally, after almost two decades of experimentation, a German chemist, Friedrich Woehler, managed to use the methods suggested by Davy to produce actual aluminium in 1845.
Since this exciting new metal was rare and therefore expensive, the wealthy thought it should be used to make lavish jewellery, and this is what they demanded. But aluminium had a lot more going for it, and it wasn’t long before it earned its rightful place at the helm of engineering and manufacturing. It took a long time for scientists to work out where to find the Bauxite and how best to extract it, but they got there in the end.
On top of all its strengths, aluminium’s ability to be infinitely recycled means it is here to stay, and we’re likely to see more and more of this metal allrounder in the not-too-distant future.
These days, most aluminium is extracted by the Hall–Héroult process, devised by American student Charles Hall and French engineer Paul Héroult in 1886. They discovered that dissolving aluminium oxide in molten cryolite was an extremely effective technique. It might have worked well, but because of the huge amounts of electricity involved, it was a costly exercise. In response to concerns about this, Héroult suggested harnessing the power of water instead, and a huge smelter was built at Rhenish Falls in Switzerland. Modern aluminium production still uses a vast amount of energy, but the finished product is also very resistant to corrosion and can be recycled forever. In fact, the recycling process saves a massive 95% of the energy needed to create new aluminium, so keep crushing those cans and putting them in the right bin!
As well as being cost-effective and sustainable, aluminium has many more properties that make it one of the world’s most useful materials. It is strong, corrosion-resistant, reflective and a great conductor of heat and electricity. It is also lightweight, non-magnetic, odour-free and exceptionally easy to form and work with.
Aluminium is used in architecture, and one of the first buildings to be built using the metal was New York’s iconic Empire State Building, completed in 1931. Perhaps one of the most unique properties of this metal is its lightness. Thanks to its relatively low weight, aluminium is a key player in transportation such as high-speed trains and aeroplanes, as well as in long-distance power lines. And although steel is still the number one choice for the automotive industry, aluminium is expected to appear in more and more vehicle designs as environmental impact becomes a greater concern. Aluminium’s toughness and lightness are what has seen it make its way into the design of mobile phones, laptops and hi-fi equipment.
On top of all its strengths, aluminium’s ability to be infinitely recycled means it is here to stay, and we’re likely to see more and more of this metal allrounder in the not-too-distant future.