Aluminum is one of the most widely used and well-known materials, continuously present in our daily lives, but few know that it is one of the metals classified as strategic by the Pentagon, which means that one of the main priorities of the government is to ensure its constant supply at the lowest possible price. In fact , the current war could not be understood without aluminum . One example is thermite grenades, which harness the latent explosive power of aluminum by using its high heat of formation (the temperature at which it separates from oxygen) to increase its explosive power. It was the basis for 70,000 hand grenades used in World War I and in World War II it was used in firebombs dropped on German and Japanese cities. Today aluminum is part of, for example, the explosive technology of a nuclear missile and its fuselage, as well as the propellant of the missiles.
With such a history, very few know the tremendous struggle that scientists had to find an effective method to extract it from bauxite, the mineral where it is found.
The hard process of extracting aluminum
This problem caught the attention of a chemistry student named Charles Martin Hall, who took it on as a personal challenge and threw himself into it body and soul in his final year at Oberlin College.
Hall was convinced that electricity had to be used to extract aluminum . Something not unreasonable, because for years chemists had used it to identify chemical elements. He built a makeshift battery and furnace in the woodshed just behind his house, and there he smelted a material called cryolite to which he added bauxite. Hall discovered that in the furnace the bauxite dissolved into the cryolite . It was then that he decided to pass an electrical current through the mixture and, to his eternal delight, discovered that silver globules were produced. It was aluminum! As soon as the balls of precious metal had cooled enough to hold, Hall carried them triumphantly to his teacher. It was February 23, 1886.
A few months later, a Frenchman named Heroult had the same idea, but Hall had already patented the process. The American Aluminum Company turned Hall’s discovery into an industrial process making him a wealthy man. Part of his fortune was bequeathed to his alma mater , Oberlin College, where he made his discovery. And there is a statue of him in the chemistry building, of course made of aluminium , as an everlasting memory of those who were able to extract from the rock one of the materials necessary for our technological world.
But the story does not end here. In 1903 another young man named Richard S. Reynolds started working for his uncle, tobacco king RR Reynolds. At that time the cigarettes and the bite were protected from humidity with very thin sheets of tin . Richard clearly saw a business opportunity, and after learning all the ins and outs of that technology, he settled 16 years later in Kentucky, the homeland of bourbon . There he created a company that supplied tin foil to both the tobacco and confectionery industries, which also used it because they believed it protected their products better than paraffin paper.
So Reynolds turned to aluminum. When the price of aluminum plummeted at the end of the 1920s, Reynolds decided to adopt it as a wrapper for the two products that give most of humanity the most pleasure : tobacco and chocolates.
Light and non-corrosive, Reynolds saw aluminum as the metal of the future and very soon offered the market a long list of products: aluminum structures for doors and windows, boats and even kitchenware. However, Reynolds’ flagship product appeared in 1947 and since then it has not been lacking in any kitchen: an aluminum sheet one or two hundredths of a millimeter thick, silver foil. Fine, stainless and harmless, as a metal it allows the passage of heat but does not allow light to pass through, preventing its pernicious effects on food.
Aluminum jumped the limit of the kitchen and was installed in practically all fields of society : the space industry, construction, communications, packaging or medicine are good examples of the versatility of a metal that we were able to extract from its environment. thanks to a student who experimented with a lump of bauxite, a makeshift battery and a furnace in the woodshed just behind his house.
Reference:
Sheller, M. (2014) Aluminum Dreams: The Making of Light Modernity, MIT Press
