Charles Martin Hall
Charles Martin Hall (born December 6, 1863 in Thompson , Ohio , † December 27, 1914 in Daytona , Florida ) was an American inventor , engineer and entrepreneur . He was best known for discovering an inexpensive way to produce aluminum .
Life
The early years
Charles Hall was born to Reverend Herman Bassett Hall and Sophronia H. Brooks. He had a brother and three sisters, one of whom died in childhood. His family moved to Oberlin (Ohio) in 1873 and Charles attended Oberlin High School there and, from 1880, Oberlin College , where he earned a Bachelor of Arts degree in 1885 . His main interests were the natural sciences.
Hall became his scientific experiments with ideas and materials of its chemistry - Professor Frank Fanning Jewett excited (1844-1926). His remark that anyone who could find a cheap process for aluminum production could get rich made the students prick up their ears. However, it is not certain whether this happily told event actually occurred.
Hall conducted his experiments in a woodshed behind his family's house. Both the Jewett House and the Hall House still exist in Oberlin, only the woodshed was demolished a long time ago. In the Oberlin Heritage Center in the Jewett House, however, the exhibition Aluminum: The Oberlin Connection shows a replica of the woodshed experiment from 1886.
The later years
After his successful aluminum extraction, Hall continued his research and development until his death. He has been granted 22 US patents , most of them relating to aluminum production. He was a member of the Oberlin College Board of Trustees , the governing body of his college. Charles Hall was Vice President of Alcoa until his death, which overtook him in Daytona , Florida , in 1914 . The inventor died unmarried and childless and was buried in Woodland Cemetery in Oberlin.
A preference for aluminum
The surrounding
Aluminum is the second most common non-ferrous metal after silicon in the earth's crust , but not in a pure (dignified) form. Aluminum was discovered in 1808 after research by Sir Humphry Davy . However, he failed in his attempt to isolate this substance, which he called alumium , from its compounds . The Danish chemist Hans Christian Ørsted succeeded in doing this in 1825 from clay . The crowd was tiny, the metal unclean. In 1827 Friedrich Wöhler succeeded in producing aluminum in a pure state for the first time, but here too only with a low yield. The metal was much more expensive than gold at the time . This preciousness aroused the desire of individual noblemen to own objects made from it.
In 1846, the French Henri Etienne Sainte-Claire Deville set about refining Wöhler's manufacturing process, began producing aluminum in 1854 and published his findings in book form in 1859. Emperor Napoléon III. commissioned his scientists to think about ways of obtaining the substance in larger quantities. The elaborate chemical process of Devilles only allowed an annual production of about 750 kilograms in 1857, which took place exclusively in France.
The invention
Hall's considerations revolved around the melt analysis described by Humphry Davy. He started looking for a way to make the alumina, which could only be melted at high temperatures and from which the aluminum could be extracted, more easily melted. In the year after graduating from college, he began experimenting. He had to manufacture most of his devices himself. He was supported by his older sister Julia.
In his experiments, Charles Hall found that the melting point of around 2050 ° C for pure aluminum oxide could be reduced to around 950 ° C by adding cryolite . He developed a process in which a strong electric current was passed through a mixture of alumina-clay and cryolite. A puddle of aluminum formed on the bottom of the reaction vessel.
Hall produced the first samples of the pure metal with his experimental set-up on February 23, 1886, after several years of intensive work. After he could initially only produce spheres from pure aluminum, he continued his experiments until he succeeded in producing aluminum bars. On July 9, 1886, Hall submitted his patent "Process of reducing aluminum from its fluoride salts by electrolysis" to the US Patent Office; the patent was granted to him the following year.
Independently of Hall, the Frenchman Paul Héroult discovered the process around the same time and received a patent for it in France. Therefore, there were initially legal disputes between the two, but they eventually came to an agreement. The manufacturing process was later referred to as the Hall-Héroult process in honor of both of them . In France, Héroult encountered a lack of interest in the exploitation of his invention and therefore teamed up with three industrialists in Switzerland .
Economic success
After Hall could not find funding for the industrial exploitation of his invention in Ohio, he went to Pittsburgh , where he made contacts with the well-known metallurgist Alfred E. Hunt . In 1888, together with other industrialists, they founded the Reduction Company of Pittsburgh , which first established a small factory and, after its success, other large aluminum production companies. In 1907 the company operated bauxite mines in Arkansas , a refinery in Illinois and three aluminum smelters in New York and Canada . Hall became a rich man as one of the major shareholders.
In 1907 the Reduction Company became the Aluminum Company of America , later abbreviated as Alcoa . It had a monopoly on industrial aluminum production for a long time and is still the global market leader today.
The Hall-Héroult process dropped the price of aluminum by a factor of 200 and made it affordable for practical use. By 1900 the annual production increased to about eight thousand tons. Today more aluminum is produced than all other non-ferrous metals combined.
The modern melt electrolysis
The Hall-Héroult process, which the Austrian Carl Josef Bayer improved again with the Bayer process for cleaning bauxite from oxides and silicates , is the basic process for today's aluminum production. This fused-salt electrolysis allowed the material to be manufactured economically from suitable alumina. A mixture of aluminum oxide and cryolite is used as the electrolyte . Next are carbon anodes and carbon cathodes used. By supplying heavy current ( direct current up to 200,000 amps ), the substances in the electrolysis bath begin to melt at a temperature of around 950 ° C. The heavier liquid aluminum collects on the floor and is sucked off.
A missing "i"
Because of Hall, the Americans now write the name of the metal aluminum as aluminum and not as aluminum like the British. On a publication handout, he had the name erroneously written, but consistent with Oberlin College, without the second i: aluminum refinement process . Because his invention was so revolutionary and made the metal very popular, this name form caught on in the USA. The different spelling in English texts often allows conclusions to be drawn about where they were created.
recognition
Hall received the Perkin Medal in 1911 for his work , the highest distinction in the American chemical industry. In 1898 he was elected a member of the American Philosophical Society .
Hall became one of the best-known benefactors of Oberlin College , where he was honored with a monument, an aluminum statue that is comparatively light. That's why students often played jokes with her and not infrequently moved her. Today the statue is securely attached to a large granite block on the second floor of the Oberlin New Science Center , but is decorated with all kinds of "jewelry" on holidays and similar occasions.
Web links
- Oberlin Heritage Center in Jewett House (English)
- Hall House (English)
- The story of Alcoa
- Aluminum in the period 1880–1905 ( Memento from April 19, 2012 in the Internet Archive )
- Brief history of aluminum
swell
- Oberlin College Archives: RG 30/182 - Charles Martin Hall (1863–1914)
- Norman C. Craig: Charles Martin Hall - the young man, his mentor, and his metal. In: Journal of Chemical Education. 63, No. 7, 1986, 557-559.
- Norman C. Craig, Christian M. Bickert: Historical metallurgy: Hall and Heroult: the men and their invention. In: CIM Bulletin. 79, No. 892. 1986, pp. 98-101.
Individual evidence
- ↑ Patent US400664 : Process of reducing aluminum from its fluoride salts by electrolysis. Registered July 9, 1886 , published April 2, 1889 , inventor: Charles M. Hall.
- ^ Member History: Charles M. Hall. American Philosophical Society, accessed September 19, 2018 .
| personal data | |
|---|---|
| SURNAME | Hall, Charles Martin |
| BRIEF DESCRIPTION | American inventor, engineer and entrepreneur |
| DATE OF BIRTH | December 6, 1863 |
| PLACE OF BIRTH | Thompson , Ohio |
| DATE OF DEATH | December 27, 1914 |
| Place of death | Daytona , Florida |