For industrial purposes, aluminium is a very special metal. It’s light but strong, it’s malleable and it’s resistant to corrosion. It conducts both heat and electricity. It doesn’t easily catch fire, and it can be recycled repeatedly without losing its structural integrity. It’s also not toxic and non-magnetic.
Aluminium has another advantage. Unlike many of the other resources we rely on, aluminium is in no danger of running out. In fact, it’s more abundant than any other metal, making up an estimated 8% of the weight of the Earth’s crust.
Although aluminium is abundant, it isn’t found naturally in its pure form. It was first isolated in 1827, when Friedrich Wöhler succeeded in producing aluminium by mixing anhydrous aluminium chloride with potassium.
Up to the 1880s, pure aluminium remained difficult to extract. Whereas today it’s a comparatively inexpensive metal, it was once more valuable than gold. It’s said that Napoleon III of France held a banquet at which only the most important guests were given aluminium cutlery; others were given the gold.
With the development of the Hall-Héroult electrolytic process in the 1880s, extracting aluminium became much cheaper and easier, and the popularity of aluminium for industrial uses began to grow. The same extraction method is still used today.
Uses of aluminium
After iron, aluminium is now the second most widely used metal in the world. On its own, it’s a soft metal, seldom used for industrial purposes. Instead it’s mixed with other metals to form alloys.
Because aluminium alloys have a high strength-to-weight ratio, they’re widely used in the aerospace and automotive industries. For example, aluminium alloys are used to manufacture the bodies of aircraft, trains, cars and bicycles, as well as for engine blocks, cylinder heads and transmission housings.
Aluminium is widely used in building structures. For example, it’s commonly used in sidings and door and window frames.
Thanks to its ability to conduct heat and cold, aluminium is used in several types of food packaging, including foil, foil trays and cans. It’s used in heat sinks for computers and transistors, in a wide range of electronics, and for radiators and air conditioners in cars. It’s also used in thawing units, for example in the pharmaceutical industry.
Because aluminium isn’t magnetic, it can be used to house coaxial cables, and because it resists corrosion, it can be used to transport other metals.
The process of aluminium extrusion has added enormously to the popularity of aluminium, and to the ease of incorporating it in a variety of structures. During extrusion, an aluminium alloy is pushed through a die with a specific shape, creating a product with a precisely defined cross-section.
This means that instead of manufacturing aluminium frames and other products from scratch, it’s possible to buy pre-made aluminium profiles (or profiles produced according to your specifications) and then simply to assemble them.
Today some manufacturers and suppliers even offer pre-made interlocking aluminium profiles, which can simply be locked together to create a huge range of different shapes and structures, with countless applications.