When bauxite (raw aluminum ore) is processed into aluminum oxide, or alumina, it's first bathed in a solution of sodium hydroxide (lye) at very high temperatures. Aluminum compounds in the bauxite dissolve while other compounds remain behind: iron oxides, sand, clay, some titanium oxides and even radioactive materials, such as uranium or thorium. That resulting red slurry (pictured above) has a lethal pH that can easily destroy plant and animal life, inflict chemical burns and even damage airways if the fumes are inhaled. |