Aluminum Foils..Invention

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.