Inventors
Charles
Martin Hall (1863-1914) - Aluminum
By
Mary
Bellis
According to
Jefferson Lab, "Scientists suspected than an unknown metal existed
in alum as early as 1787, but they did not have a way to extract it until
1825. Hans Christian Oersted, a Danish chemist, was the first to produce
tiny amounts of aluminum. Two years later, Friedrich Wöhler, a German
chemist, developed a different way to obtain the metal. By 1845, he was
able to produce samples large enough to determine some of aluminum's basic
properties. Wöhler's method was improved in 1854 by Henri Étienne
Sainte-Claire Deville, a French chemist. Deville's process allowed for
the commercial production of aluminum. As a result, the price of the metal
dropped from around $1200 per kilogram in 1852 to around $40 per kilogram
in 1859. Unfortunately, the metal remained too expensive to be widely used."
U.S.
patent #400,666
Then on April
2, 1889, Charles Martin Hall patented an inexpensive method for the production
of aluminum, which brought the metal into wide commercial use.
Charles Martin
Hall had just graduated from Oberlin College (loacated in Oberlin, Ohio)
in 1885 with a bachelor's degree in chemistry, when he invented his method
of manufacturing pure aluminum.
According to
Jefferson Lab, "Although aluminum is the most abundant metal in the earth's
crust, it is never found free in nature. All of the earth's aluminum has
combined with other elements to form compounds. Two of the most common
compounds are alum, such as potassium aluminum sulfate (KAl(SO4)2·12H2O),
and aluminum oxide (Al2O3). About 8.2% of the earth's crust is composed
of aluminum."
Pure aluminum
was so rare at that time it was considered a precious metal. Charles Martin
Hall's method of processing the metal ore was to pass an electric current
through a non-metallic conductor (molten sodium fluoride compound was used)
to separate the very conductive aluminum. In 1889, Charles Martin Hull
was awarded U.S. patent #400,666 for his process.
In 1888, together
with financier Alfred E. Hunt, Charles Martin Hall founded the Pittsburgh
Reduction Company now know as the Aluminum Company of America (ALCOA).
By 1914, Charles Martin Hall had brought the cost of aluminum down to 18
cents a pound and it was no longer considered a precious metal.
Charles
Martin Hall - Biography
Charles Martin Hall, chemist, manufacturer
of aluminum, and Oberlin College benefactor, was born December 6, 1863
in Thompson, Ohio.
American, Charles Martin Hall had
invented a process for obtaining aluminum from aluminum oxide. It should
be noted that Paul L. T. Heroult, a French chemist, also invented this
same process independently in 1886.
One other inventor needs to be noted,
Karl Joseph Bayer, an Austrian chemist, developed a new process in 1888
that could cheaply obtain aluminum oxide from bauxite. Bauxite is an ore
that contains a large amount of aluminum hydroxide (Al2O3·3H2O),
along with other compounds. The Hall-Héroult and/or Bayer methods
are still used today to produce nearly all of the world's aluminum.
Aluminum
Foil
Metal foil has been around for centuries.
Foil is solid metal that has been reduced to a leaf-like thinness by beating
or rolling. The first mass-produced and widely-used foil was made from
tin. Tin was later replaced by aluminum in 1910, when the first aluminum
foil rolling plant “Dr. Lauber, Neher & Cie., Emmishofen.” was opened
in Kreuzlingen, Switzerland.
The plant, owned by J.G. Neher &
Sons (aluminum manufacturers) started in 1886 in Schaffhausen, Switzerland,
at the foot of the Rhine Falls - capturing the falls’ energy to produce
aluminum. Neher's sons together with Dr. Lauber discovered the endless
rolling process and the use of aluminum foil as a protective barrier. From
there began the wide use of aluminum foil in the packaging of chocolate
bars and tobacco products. Processes evolved over time to include the use
of print, color, lacquer, laminate and the embossing of the aluminum.
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