From its isolation by Ørsted in 1825 to the invention of the Halls-Héroult process in 1886, aluminum went on a surprising journey from being a rare to an omnipresent metal.
Time and again, when I hold a can of soda in my hand, I wish I had a time machine so that I could travel back to the 1800s and become rich by selling what most of us now consider trash.
Not long ago, aluminum found its place in French museums alongside the crown jewels, heralded as something rare and special and valuable.
Today we crumple a drink can or a foil wrap with our bare hands and toss it into the garbage without a second thought. Rewinding 160 years into the past, these pieces of metal could earn us enough money to get a lifetime Netflix subscription.
Let’s take a look at the exceptional journey taken by this 13th element of the periodic table.
Ancient Use of Aluminum
Mankind has reaped the benefits of aluminum-bearing compounds since before the discovery of aluminum as an element. A commonly found component of volcanic clay is “Alum”(potassium aluminum sulphate).
In the ancient civilizations of Mesopotamia, Sumeria and Egypt, people mined and refined clay to extract alum. They prepared medicines, dyes, pickling agents for food and fire depressants from this material. Ponds containing the bitter salt water were used for treating external bruises and wounds.
One of the earliest mentions of what could be aluminum was in Pliny the Elder’s book “The Natural History”. He mentions a story about a goldsmith who presented before the Roman emperor, Tiberius, a goblet. This cup was made of a strange silvery, shiny metal that was too light to be silver.
The goldsmith claimed that the knowledge of extracting the metal from clay belonged only to him and the gods. The emperor seemed interested, but soon realized that the rare metal would deem all his gold and silver treasures invaluable. Instead of rewarding the man, Tiberius ordered his soldiers to behead the goldsmith. And with him died the secret.
Aluminum in the early 1800s
Aluminum(Al) is the most abundant metal in nature, as it makes up 8.1% of the Earth’s crust. However, unlike copper, silver, or gold, aluminum isn’t found in a free state in nature. It is locked in highly stable compounds. The attempts to obtain free Al began post- Scientific Revolution, in the early 1800s. Electrolysis became popular after Alessandro Volta’s invention of portable electricity, the “Voltaic Pile”.
Humphry Davy, a Cornish chemist, was using electrolysis to conduct experiments on molten salts. He isolated metals like sodium, potassium, calcium, barium, magnesium, and strontium by passing electricity through their molten salts. While working with a kind of bitter salt, he identified the presence of a new metal, which he named Alumium. He named it after the Latin word”alumen“, which meant “bitter salt”.
How did he know it was bitter, you ask? Because he tasted it, like most scientists of his time. Unfortunately, he tried until he died, but could never isolate the pure metal from its salt.
Aluminum in the early 1900s
In the year 1925, in a lab at the University of Copenhagen, Hans Christian Ørsted concocted a mixture of aluminum chloride and potassium amalgam. On rapid heating, the mixture produced the first-ever globules of aluminum metal, but Ørsted ‘s experiment wasn’t reproducible and produced very little aluminum.
A German chemist Friedrich Wöhler tried to improve Ørsted’s technique by using potassium instead of potassium amalgam, but he wasn’t very successful either. The first person to have extracted aluminum by electrolysis was Robert Bunsen. (Yes, the bunsen burner guy! Although it was his assistant, Peter Desaga, who actually designed it). However, Bunsen moved on to other fields like developing batteries and antidotes for arsenic poisoning.
Meanwhile, a geologist named Pierre Berthier discovered Bauxite ore (aluminum oxide) in Les Baux, France. A Parisian named Henri Sainte-Claire Deville developed a method of reducing the aluminum oxide ore to aluminum. His method was expensive but effective. This made aluminum even more precious than gold and silver. It is said that Napoleon III had cutlery made of aluminum. Only his special guests got to use them, while others were given gold and silverware.
To showcase the country’s industrial prowess, the US used 6 pounds of aluminum to make the Washington Monument’s capstone. Aluminum became a buzzword at royal and government meetings.
Charles Dickens was the editor of a weekly magazine called Household Words, in which he described aluminum as “What do you think of metal as white as silver, as unalterable as gold, as easily melted as copper, as tough as iron, which is malleable, ductile, and with the singular quality of being lighter than glass?” Thus, extracting the elusive metal from its combined to its metallic form became equivalent to finding the mythical city of El Dorado.
Beginning of the Aluminum Revolution
Aluminum ruled as the most expensive metal for almost 60 years, but was dethroned when the “aluminum twins” Charles M. Hall and Paul Héroult came into the picture. Charles Hall became determined to find a way of extracting pure aluminum after his professor Professor Frank F. Jewett spoke about Friedrich Wöhler’s work and showed them a piece of aluminum at their university reunion. Hall started working from the laboratory he had set up on the third floor, but soon his work set it on fire.
Thus, he moved to his father’s woodshed. With the help of his sister Julia, who was also a chemist, he experimented with electrolytes to dissolve the aluminum salts. He then zapped the solution with electricity from handmade batteries (because there was no grid power supply). Finally, in February 1886 he settled on cryolite (sodium aluminum fluoride) and developed a method for the extraction of pure aluminum from its compounds.
Completely oblivious of Hall’s work, a French innovative engineer named Paul Héroult was working out of his family’s tannery in search of pure aluminum. Héroult’s interest in aluminum extraction was sparked by his chemistry professor Henry Louis Le Chatelier, whose father was a close associate of Henri Sainte-Claire Deville. With the help of his friends, he developed a method of extracting pure aluminum from its ore using cryolite and electrolysis.
In April 1886, he had enough evidence to file for a patent in both France and the USA. The similarity in their work was discovered when Hall filed for a patent in July 1886 and was informed that Héroult had already applied for it. After long litigation, Hall got his patent in America, and the process was named the “Halls- Héroult ” process.
Many companies got a license for using their patents and started bulk production of aluminum. This drastically lowered the price of the metal. Both of the inventors made a lot of money from their inventions, and also made way for the aluminum revolution.
Another man who was also responsible for making aluminum a household name is Karl Josef Bayer. He developed a cost-effective method of extracting pure alumina from Bauxite ore. The extraction of this metal became much more cost- and energy-efficient by combining Bayer’s and the Halls- Héroult process.
Aluminum and its alloys have completely revolutionized the world in which we live. It is everywhere, from cooking utensils to pyrotechnic powders to the heat sinks of your CPU. Due to its lightweight, non-corrosive nature and excellent mechanical properties, it has made air and space travel a reality. So, if the next person beside you on a plane says that they’re scared of flying in a tin can, just provide some comfort by reminding them that it is actually an aluminum can… that should make them feel better!
- Science History Institute
- A Brief History of Aluminum and Its Alloys
- Periodic Tales: A Cultural History of the Elements, from Arsenic to Zinc Paperback – 28 February 2012 by Hugh Aldersey-Williams
- Production of Aluminum: The Hall-Héroult Process
- Revues et ouvrages en sciences humaines et sociales
- Essential Readings in Light Metals Journal