From Bauxite to Alumina: The Bayer Process
By Cody Berry
Since our new exhibit is focused on the town of Bauxite, and the industry that built it, I wanted to answer some commonly asked questions. The question explored in this article: “What happens to the bauxite after it’s dug up?”
Once the bauxite ore was mined, there was a complex process a company would need to follow before it eventually became aluminum.
The key ingredient in making aluminum is aluminum oxide, more commonly known as alumina. Alumina can be extracted from bauxite ore. But how is the alumina extracted from the bauxite? The Bayer Process.
Invented by Austrian chemist Carl Josef Bayer in 1887, the Bayer Process has four steps. First, after the bauxite is crushed, washed, and dried, it is dissolved with caustic soda at very high temperatures. After that, the mixture is filtered to remove any impurities or “red mud.”1
The remaining solution is then transferred to big tanks called precipitators. Inside the tanks, the solution cools down and aluminum hydroxide seeds are added to stimulate the precipitation of solid crystals. Aluminum hydroxide crystals settle on the bottom of the tank and are removed. Finally, the crystals are washed of any remaining caustic soda and heated to remove any water. Alumina emerges as a white powder that looks like sugar but it’s hard enough to scratch glass.2
At the Gann Museum, we have some bauxite samples and vials of alumina on display. These came from the Hurricane Creek Plant which was operated by the Reynolds Metals Company. In our exhibit “How Bauxite Built A Town: 1896-1984,” we have a photo of the plant itself and some from our Alcoa Collection of Hurricane Creek as well. Our next article will focus on the Hall-Heroult Process, which is the next step in turning the bauxite ore into aluminum. The process involves the electrolysis of molten alumina.
Citations:
1 The Aluminum Association, “Alumina Refining 101,” https://www.aluminum.org/alumina-refining-101, Date Accessed April 5, 2025.
2 The Aluminum Association, “Alumina Refining 101,” https://www.aluminum.org/alumina-refining-101, Date Accessed April 5, 2025