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When aluminum was first introduced to the public at the Paris Exposition of 1855, a writer for National Magazine remarked, “just now, in this new metal, so long concealed in every hill-side, and even in the very dust of our streets, science seems about to make over to the arts one of her occasional bestowments, by which both the knowledge and power of our race are, at an instant, so widely increased.”
Aluminum, the third most abundant element in the earth’s crust — and its most plentiful metal — is made from bauxite, a reddish-brown rock discovered in Les Baux, France, in 1821. But it wasn’t until 1886 that chemists finally discovered an economical way to separate pure aluminum from its ore. Two years later, on Thanksgiving Day, a pilot plant in Pittsburgh introduced the first commercial aluminum.
As predicted, the commercialization of this light, lustrous and non-rusting metal has revolutionized the world. Today, aluminum is used to make everything from aircraft to art, buildings, power lines and packaging.
In 1886, Charles Martin Hall of the United States and Paul L.T. Héroult of France — both age 22 — independently discovered the way to produce aluminum economically. Hall, under the initial direction of his Oberlin College professor, Frank Fanning Jewett, developed a method for “reducing” aluminum oxide, called alumina, to pure aluminum by electrolysis. In the electrolytic cell, alumina is dissolved in molten cryolite. A strong electric current passes through the solution and removes the oxygen, leaving deposits of nearly pure aluminum on the bottom of the bath. These deposits are siphoned off and cast into pigs. This method is still used today.
Visit National Historic Chemical Landmarks to read more about aluminum processing.
Excerpted with permission, National Historic Chemical Landmarks Program
www.acs.org/landmarks