Charles Martin Hall and the Great Aluminum Revolution Vinay Kumar and Linda ~ i l e w s k l Ph,socal Sc ences Depanmenl honhorn i(cn1ucry Lnlvcrsily hqnana Helgnls. KY 41076
Charles M. Hall, a great inventor, metallurgist, philanthropist, and founder of the modern aluminum industry, was horn on December 6, 1863, a t Thompson, Ohio. His father was a protestant clergyman, and in 1873 the family moved to Oberlin, Ohio. Charles was a prolific reader and completed elementary school a t an early age. During his childhood, Julia, an older sister, was Charles' closest companion and confidante, a role that she continued to play even later in his life. It is reported ( 1 ) that both Charles and Julia remained single throughout their lives. As a youngster Charles was intensely interested in chemistry and by the age of six was using his father's old chemistry book as a primer. He performed experiments with materials from the kitchen and the local drug store. He is said to have been scolded once for ruining a tablecloth with homemade fireworks. Before entering high school, Charles (Fig. 1)studied music and piano, which later became a favorite pasttime for him (2). Hall's chemistry professor a t Oberlin College, Frank F. Jewett, a former pupil of Wohler, was so impressed with Charles's ability and interest in the subject that he was offered a place to work in Jewett's own private laboratory (2). ., Aluminum had been isolated in 1825 in a highly impure form by Hans Christian Oersted of Denmark (3).Two years later, a better preparation was reported by Friedrich Wohler. Both senarated the metal from its chloride throueh the action of pdtassium. Aluminum attracted considerafie attention because of its lightness and the abundance of its mineral ore. However, the use of expensive potassium for its preparation did not permit a large-scale production of aluminum. In 1854, the great French chemist, Henri SainteClaire Deville, substituted sodium as a reducing agent and also suggested the use of bauxite ore. His process greatly lowered the production cost, hut not to a point permitting widesoread use of aluminum (3). . , Thus. durine" the 19th century, aluminum remained a precious metal. ~
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Legend has it that Napoleon 111's cutlery and his baby's rattle were made of aluminum. I t is said that while the majority of his guests were served in gold plates, those he wished to impress were served from aluminum plates (5). The cap on the top of the Washington monument, which was dedicated in 1885 in Washington, DC, was also made of the then expensive metal aluminum ( 4 ) . During Hall's junior year, Jewett told his class about the financial and social rewards of inventing an inexpensive process for the production of aluminum. Stimulated and inspired by Jewett's comments, Hall began the search for an inexpensive process for purifying aluminum while he was still an undergraduate. He devoted himself to a serious and extensive study of the metal, and experimented tirelessly in a% improvised laboratory in his family's woodshed. He was ably assisted in his work by Julia.
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Journal of Chemical Education
Figure 1. Charles Martin Hail as a youth.
Figure 2. Statue of Charles Martin Hall as a college student. cast in aluminum, on the camps of Oberlin College. Photo courtesy of Oberlin. College.
Using a clay crucihle, carbon rod (anode), and homemade batteries, Hall carried out the electrolysis of alumina, the purified oxide ore of aluminum. T o lower its melting point the alumina was dissolved in 10-15% fused cryolite, a double fluoride of aluminum and sodium. With the passing of the current, Hall noticed the appearance of bubbles. However, no aluminum was precipitated. He guessed that the electric current was decomposing the silica from the crucible, thus freeing silicon. He solved the problem by lining the crucihle with carbon, which also acted as the cathode. On February 23, 1886, he saw globules of aluminum collecting a t the cathode. Excitedly, he rushed to Jewett's office and held out to him a handful of his first sample in the form of buttons (6). Later these became the aluminum "crown jewels", and
are still reverentlv- oreserved hv the Aluminum Company of . ,\mvrica in Pittslmrgh (5, 61. Initiall\.. 11nll llad dit'iirulties rettinz financial backine for his proce8;. In 1888, through the support of Captain ~ l ? r e d Hunt. he founded the Pittsbureh Reduction Comoanv, . .. which later became the ~ l u m i n u mCompany of America (ALCOA). On April 2.1889, Hall was issued a oatent for his process. Working independently in 1886, Paul-Louis-Toussaint HBroult, a young French chemist of the same age as Hall, devised the same method for the production of aluminum. Even though, HBroult had obtained a French patent the same year as Hall, a U.S. court in 1893 sustained Hall's patent and conceded the priority of invention to him (7). According to Trescott ( I ) , Julia's six-page document entitled, "History of C. M. Hall's Aluminum Invention", and her testimony served to clinch Hall's victory in the Hall-HBroult oatent interference case. By 1907, ALCOA owned several bauxite mines, three aluminum plants, and was producing 15 million pounds of the metal annually (2). While the commercial production of aluminum continued to climb, its price dropped dramatically from $500/lh. to $8/lh. in 1884, $5/lh. in 1886, $l/lh. in 1888, $0.70Ah. in 1893, and $0.18Ab. in 1914 (2). The great discovery of aluminum has made possible the present widespread use of this metal for domestic, industrial, and transportation purposes. Since World War I, there has been continuing progress in the design of aluminum alloys containing copper, manganese, magnesium, and other metals. By 1930, airplanes made out of aluminum alloy were in use. Since World War 11. aluminum manufacturers have invested so heavilv and imaginatively in research to develop new aluminum oroducts and uses that todav the metal is outranked onlv. bv. iron in importance. Hall was the recipient of several honorarv demees and awards. His almamker elected him a trustee.-1n 1911, when the Perkin Medal was awarded to Hall by the American Section of the Society of Chemical Industry, HBroult travelled to America to he oresent at the award ceremonv and to congratulate him personally (6). Halllived modestly, indulging only in his hobbies of music and the collection of oriental rugs. In 1908, his health suffered due to leukemia. Hall died in Florida on December 27, 1914, a t the age of 51. In his will, he left nearly five million dollars to Oberlin College. Out of those funds, an auditorium was built on the camnus in memorv of his mother. Soohronia Brooks Hall, who had died before his graduatidn fiom the college in 1885 (2). Todav. a beautiful statue of the vouthful ~al1,"castin al&num, may also be viewed at 0he;lin College (Fig. 2) (6). Llterature Cited 1. Tro~cott,Martha M. J . Chsm. Edue 1977, N ,24. 2. Hey,, Ernert V . F;m ofcenius,h e n t o r s of ths Pmst Century: Anchor (Doubledayl: New York, 1976: pp 221-239. 8. Ihd*, Aaron. The Deuelapmant o/ Modem Chemistry; Harper and Row:New York, 19% pp467-468.6%. 4. Asirnou, Isaac. Asimou's Biogrephicol Enwclopadio o/ Science nnd Terhnoiagy, 2nd ed.: Doubleday: Garden City, NY, 1982: p 698. 6. Daintith. J.; Mitchell. S.; Tonfill. E., Eds. Biogrophicol Encyclopedia a/ Scientists; Factson File: New York, 1981: Vol. 1.0146. 6. Weeks, M. E. Dirrovary o/ the Element% 6th ed., Journal u? Chemical Education: Easton. PA, 1956: pp 6 0 2 4 0 8 . 7. Who Wos Who in American Hidoiv. Science ond Technolozv:Marauis Who's Who: Chbago. 1976: p244. 8. Gillispie. Charles C., Ed. Drclionary o/ Scientific Biography; Vol VI. Seribner'a: New Ynrk, 1971: Vol. 6, pp W 5 1 .
Volume 64
Number 8 August 1987
891
