How was aluminum discovered?

Alright, the story of how aluminum was discovered is a fascinating one, spanning thousands of years, from ancient unconscious use to modern mass production.

The discovery process of aluminum can be clearly divided into three stages:

Stage 1: The Ancient "Unsung Hero" – The Use of Alum

Aluminum is the most abundant metal in the Earth's crust, but it is extremely reactive and never exists in its pure form in nature. Ancient people used aluminum compounds very early on, the most famous being alum.

• Time: At least the 5th century BC
• People: The ancient Greeks and Romans
• Discovery: They discovered a mineral called "alum" and used it as a mordant in dyeing (to fix colors) and as a styptic (to stop bleeding). They had no idea this substance contained an unknown metallic element.
• The name "Aluminum" itself is derived from "Alum."

Stage 2: Scientific "Identification" – Recognizing a New Element from its Compounds 

With the development of modern chemistry, scientists began to realize that a new metal might be hidden within substances like alum. 

• Key Figures:
• Humphry Davy: This British chemist discovered reactive metals like sodium and potassium through electrolysis between 1807 and 1808. He also attempted to extract metal from alum but failed. However, in 1808 he formally proposed a name for this unknown metal. He initially intended to call it "Alumium," later changing it to "Aluminum." This spelling was retained in the U.S. and Canada, while in most other parts of the world, the IUPAC designated name became "Aluminium."
• Hans Christian Ørsted: A Danish chemist. In 1825, he successfully isolated some impure metallic aluminum particles. He used potassium amalgam to reduce anhydrous aluminum chloride and then distilled away the mercury to obtain a metal with a color and luster similar to tin. This was the first scientific preparation of aluminum, but because the product was impure and his publication was in Danish, it did not gain widespread attention at the time.
• Friedrich Wöhler: A German chemist. In 1827, using a similar but improved method (using metallic potassium to reduce anhydrous aluminum chloride), he succeeded in obtaining relatively pure aluminum powder and was the first to describe some basic properties of aluminum, such as its low density and resistance to corrosion. Therefore, the scientific community generally associates the year 1827 and Wöhler's name with the discovery of aluminum. 

Stage 3: From "Royal Treasure" to "Common Material" – The Breakthrough in Smelting Technology 

After Wöhler, aluminum was confirmed, but its extraction remained extremely difficult (requiring expensive potassium), making it more expensive than gold. 

• "The Emperor's Gold":
• In the mid-19th century, aluminum was considered a rare and precious metal.
• French Emperor Napoleon III used aluminum tableware to honor his most distinguished guests at state banquets, while others had to use gold tableware. He also provided funds to support research into the industrial production of aluminum, hoping to use it for lightweight military equipment.
• The apex of the Washington Monument (built in 1884) was capped with a 6.3 lb (2.8 kg) pyramid of aluminum, a hugely symbolic and extravagant act for the time.
• The Revolutionary Breakthrough – The Hall-Héroult Process:
• Time: 1886
• People:
• Charles Martin Hall: A recent American college graduate.
• Paul Héroult: A French student of the same age.
• Discovery Process: The two, working independently and unaware of each other, invented the same electrolytic process almost simultaneously. They discovered that dissolving alumina (aluminum oxide) in molten cryolite and then passing a direct electric current through it would yield liquid metallic aluminum at the cathode.
• Significance: This method drastically reduced production costs, making the large-scale industrial production of aluminum possible. From then on, aluminum transformed from an expensive "royal metal" into a common industrial raw material, laying the foundation for the aviation, construction, and packaging industries of the 20th century.