The Encyclopedia Americana (1920)/Bauxite
BAUXITE, or BEAUXITE, bo'zīt (from
Baux, or Beaux, near Arles, France, where it
occurs), a native, hydrated oxide of aluminum,
having the formula AlO2HO. It has a
specific gravity of about 2.5, and its hardness
ranges from 1 to 3. It occurs massive, in
concretionary grains showing a concentric structure
and in clay-like deposits.  Sesquioxide of iron
is usually present in considerable quantity, —
sometimes to the extent of 50 per cent, — part
of it replacing aluminum, and part occurring
merely as an impurity. Bauxite is found in
many parts of the world. One of the most
interesting deposits is at Irish Hill, near Larne,
county Antrim, Ireland, where it occurs in
the iron measures together with lignite. At
this place three layers of it are known, having
an aggregate thickness of about 50 feet. The
finest grade from Irish Hill is almost free from
iron, containing as little of that metal as good
china clay. Analyses have shown that the
color of bauxite is no criterion of the freedom
of the mineral from iron, since a white variety
containing 3.67 per cent of FeO is known,
while a certain strongly red variety showed,
upon analysis, but 3.75 per cent, and a yellow
specimen contained 14.39 per cent. In the United
States bauxite occurs in considerable quantities
in Saline and Pulaski counties, Ark.,

and in a deposit extending from Calhoun County,
Ala., eastward into Georgia. Bauxite
forms the principal ore of the metal aluminum.
The American deposits of bauxite are well
suited to the production of aluminum, as ore
can be had in quantity that contains as little
as 1 per cent of iron oxide, and 3 per cent of
silica. Bauxite, in some localities, is undoubtedly
an alteration product of basaltic rocks,
while in other localities (especially in the United
States) it has very likely been deposited by
hot springs. The deposits of Georgia and
Alabama are thought to have resulted from
hot springs, the waters of which were
rendered acid by passing through pyritic
shales. The sulphuric acid is believed to
have reacted with shale beds changing the
kaolin to aluminum sulphate. As this passed
on upward through limestone beds, the reaction
freed AlO as follows: Al(SO)+CaCO
= 3CaSO+AlO+3CO. The gelatinous AlO
was then deposited as bauxite. The Arkansas
deposits are believed to be residual from the
weathering of syenite. In addition to its use as
an ore of aluminum, bauxite forms an important
source of alum. Its clay-like form is known as
wocheinite, on account of its occurrence at Wochein,
in Styria. The world's product of bauxite
was in 1910 about 310,000 tons; 1914 about 350,000
tons; and 1915 something over 500,000 tons;
the average value in the United States being
about $3 per ton. Of the 1915 production the
United States is credited with 297,000 tons;
France, 180,000; United Kingdom, 20,000; Italy,
10,000; Japan, 250; India, 110; all other countries,
2,600. Consult Hayes, C. Willard, ‘Bauxite’
(Sixteenth Annual Report of the United States
Geological Survey, Part 3, Washington 1896);
Branner, ‘The Bauxite Deposits of Arkansas’
(Journal of Geology, Vol. V, 1897, p. 263);
Mead, J. W., ‘Bauxite Deposits of Arkansas’
(Econ. Geol., Vol. X, 1915, p. 28). See
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