Definition of "alumina" []

• Any of several forms of aluminum oxide, Al2O3, occurring naturally as corundum, in a hydrated form in bauxite, and with various impurities as ruby, sapphire, and emery, used in aluminum production and in abrasives, refractories, ceramics, and electrical insulation. Also called aluminum oxide. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Alcoa is also expected to benefit from the rise in alumina, a key raw material that is used to make aluminum."
• ""The primary reason we see gradually declining prices is the 60% increase in Chinese alumina capacity to about 22% of available world alumina supply," they wrote."
• "In both cases, much of the pollution comes from the waste left after alumina, which is used to manufacture aluminum, is extracted from bauxite ore."