Hall, Charles

AMERICAN CHEMIST
1863–1914

Although aluminum is now widely used as a structural material, this was not always the case. Common in Earth's crust, aluminum is difficult to win from its ore because it is such a reactive metal . In the 1850s French chemists interested Napoléon III in this rare and costly metal; he considered using it for soldiers' helmets, and even reserved a set of aluminum tableware for his most honored guests. By the 1880s chemical reduction techniques had been discovered, and the price per pound dropped from over $100,000 to near $100.

Born in Thompson, Oregon, on December 6, 1863, Charles Martin Hall was interested in minerals since the age of twelve. While enrolled at Oberlin College in Ohio, Hall took a class from distinguished professor Frank Fanning Jewett, who had a sample of the precious metal to show the class. After a stirring lecture on the topic, he finished with, "Any person who discovers a process by which aluminum can be made on a commercial scale will bless humanity and make a fortune for himself." Inspired by such a win-win challenge, Hall reportedly said, "I'm going for that metal."

After graduating from Oberlin in June 1885, Hall continued his work in a woodshed behind his family home. There, starting with a blacksmith's forge and galvanic cells constructed from fruit jars, he began to investigate mixtures of aluminum and fluorine-containing minerals. Along with help from his sister (an Oberlin student) and continued guidance from Jewett, Hall discovered that alumina (Al₂O₃) and the mineral cryolite (Na₃AlF₆) fuse well and do so at a relatively low temperature (near 1,000°C [1,832°F]), compared to pure alumina. After months of work, Hall and his sister broke open their graphite crucible on February 23, 1886, to find tiny globules of a silvery metal—aluminum. Hall rushed to show them to Jewett, who confirmed his discovery. These same samples are preserved by Alcoa as the company's "crown jewels."

Hall's next move in his quest to "bless humanity and make a fortune for himself" was to make aluminum production commercially feasible. Upon receiving the financial backing of local industrialists, the Pittsburgh Reduction Company was formed, and Hall and his employee Arthur Vining Davis

produced the first commercial aluminum on Thanksgiving Day, 1888. There still remained complicated patent infringement cases to argue, but eventually Hall was victorious. A more serious challenge came from the independent codiscoverer of the process, Paul Héroult, a French chemist the same age as Hall performing basic research on aluminum-containing compounds. Héroult filed for a patent about the same time that Hall did, but again, Hall won the dispute over patent rights. Nevertheless, the electrolytic reduction of aluminum is rightly named the Hall-Héroult process, honoring both of its discoverers.

Once again, a chemical idea had turned industrial, as the price per pound of aluminum dropped from $4.86 in 1888 to $0.78 in 1893. In 1907 the company was reorganized as the Aluminum Company of America (Alcoa), of which Hall was made a vice-president. In 1911 Hall was awarded the Perkin Medal for his process; Héroult graciously traveled across the Atlantic to congratulate him at the ceremony. Before his death in 1914, Hall donated one-third of his fortune to a grateful Oberlin College, where today stands a life-sized statue of its benefactor, constructed entirely of aluminum.

see also Aluminum; Industrial Chemistry, Inorganic.

Mark A. Pichaj

Bibliography

Weeks, Mary Elvira (1968). Discovery of the Elements, 7th edition, rev. Henry M. Leicester. Easton, PA: Journal of Chemical Education.

Zumdahl, Steven S., and Zumdahl, Susan A. (2000). Chemistry, 5th edition. Boston: Houghton Mifflin.

Internet Resources

Craig, Norman C. "Charles Martin Hall and the Electrolytic Process for Refining Aluminum." Oberlin College Chemistry Department. Available from <http://www.oberlin.edu/chem/history/cmh>.