The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide). Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al 2 O 3), the rest being a mixture of silica, various iron oxides, and titanium dioxide.
Quick Read. The story of aluminum's history of use in the U.S. now stretches over 100 years. The start was a modest one, however. Because of the complexities of refining aluminum from ore, aluminum was considered more rare and precious than gold or silver through most of the 19th century.
What is caustic soda used for? Caustic soda - or sodium hydroxide - is the natural co-product of chlorine production; indeed, the laws of chemistry define that for every tonne of chlorine you produce, about 1100 kg of caustic soda is also produced, together with 28 kg of hydrogen.