Page 102 - Encyclopedia of Chemical Compounds 3 Vols

ALUMINUM OXIDE

Interesting Facts

• The hardness of materials • The invention of a method
is measured on the Mohs for making aluminum
scale, named after the metal from aluminum
German mineralogist oxide by the 23-year-old
Frederick Mohs (1773–1839), American chemist Charles
who suggested the system. Martin Hall (1863–1914)
The scale runs from 1 (the in 1886 resulted in a
softest known natural reduction in the price
material, talc) to 10 (the of aluminum metal from
hardest known natural about twelve dollars a
material, diamond). pound to less than a dollar
Corundum has a hardness a pound.
of 8.8 on the Mohs scale.

of furnaces or the manufacture of glass and ceramic materi-
als that will not melt when exposed to very high tempera-
tures. Some other uses of aluminum oxide include:
• In finely-divided form, as the packing material in chro-
matographic columns. Chromatography is a process by
which individual components of a mixture are sepa-
rated from each other by passing them through a tube
filled with some absorbent material (such as aluminum
oxide).
• As a catalyst in many industrial chemical reactions;
• In the paper-making process, as a filler that adds body
to the final product;

• For the production of artificial gemstones;
• As a food additives, where it acts as a dispersant, a
substance that keeps a product from clumping together
in a package; and
• As the internal coating on frosted light bulbs.
The U.S. Occupational Safety and Health Administration
(OSHA) classifies aluminum oxide as a nuisance dust in the
workplace. A nuisance dust is one for which no serious
harmful effects have been identified as long as its release
is kept under control. It may, however, cause unpleasant

CHEMICAL COMPOUNDS 51