Activated Alumina, A Peculiar Material
The Activated Alumina refining process is old. Also named "Aluminum Oxide" The craft dates back to the 1880s when the Bayer company developed it for the aluminum industry. They crush up "Bauxite" (a raw material mined from the Earth) and mix it with sodium hydroxide.
Typically, "Activated Alumina" can be in granular form or a uniform "beaded" (shown above) substance that is porous and used as a substrate for catalysts and as an adsorbent for removing water from gases and liquids.
Smelter-grade alumina accounts for 90 percent of all the alumina produced; it's transported to aluminum plants, electrolyzed and formed into aluminum metal.
These products exhibit the well known alumina properties, including low electric conductivity, resistance to chemical attack, high strength, extreme hardness (9 on the Mohs hardness scale, the highest rating being 10), and high melting point (approximately 2,050 °C, or 3,700 °F).