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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| History of aluminium | 5/7 | https://en.wikipedia.org/wiki/History_of_aluminium | reference | science, encyclopedia | 2026-05-05T16:15:10.045847+00:00 | kb-cron |
Aluminium was first produced independently using electrolysis in 1854 by the German chemist Robert Bunsen and Deville. Their methods did not become the basis for industrial production of aluminium because electrical supplies were inefficient at the time. This changed only with Belgian engineer Zénobe Gramme's invention of the dynamo in 1870, which made creation of large amounts of electricity possible. The invention of the three-phase current by Russian engineer Mikhail Dolivo-Dobrovolsky in 1889 made transmission of this electricity over long distances achievable. Soon after his discovery, Bunsen moved on to other areas of interest while Deville's work was noticed by Napoleon III; this was the reason Deville's Napoleon-funded research on aluminium production had been started. Deville quickly realized electrolytic production was impractical at the time and moved on to chemical methods, presenting results later that year. Electrolytic mass production remained difficult because electrolytic baths could not withstand prolonged contact with molten salts, succumbing to corrosion. The first attempt to overcome this for aluminium production was made by American engineer Charles Bradley in 1883. Bradley heated aluminium salts internally: the highest temperature was inside the bath and the lowest was on its walls, where salts would solidify and protect the bath. Bradley then sold his patent claim to brothers Alfred and Eugene Cowles, who used it at a smelter in Lockport and later in Stoke-upon-Trent but the method was modified to yield alloys rather than pure aluminium. Bradley applied for a patent in 1883; due to his broad wordings, it was rejected as composed of prior art. After a necessary two-year break, he re-applied. This process lasted for six years, as the patent office questioned whether Bradley's ideas were original. When Bradley was granted a patent, electrolytic aluminium production had already been in place for several years. The first large-scale production method was independently developed by French engineer Paul Héroult and American engineer Charles Martin Hall in 1886; it is now known as the Hall–Héroult process. Pure alumina's very high melting point made electrolysis impractical; both Héroult and Hall realized it could be greatly lowered by the presence of molten cryolite. Héroult was granted a patent in France in April and subsequently in several other European countries; he also applied for a U.S. patent in May. After securing a patent, Héroult could not find interest in his invention. When asking professionals for advice, he was told there was no demand for aluminium but some for aluminium bronze. The factory in Salindres did not wish to improve its process. In 1888, Héroult and his companions founded Aluminium Industrie Aktiengesellschaft and started industrial production of aluminium bronze in Neuhausen am Rheinfall. Then, Société électrométallurgique française was founded in Paris. They convinced Héroult to return to France, purchased his patents, and appointed him as the director of a smelter in Isère, which produced aluminium bronze on a large scale at first and pure aluminium in a few months.
At the same time, Hall produced aluminium by the same process in his home at Oberlin. He applied for a patent in July, and the patent office notified Hall of an "interference" with Héroult's application. The Cowles brothers offered legal support. By then, Hall had failed to develop a commercial process for his first investors, and he turned to experimenting at Cowles' smelter in Lockport. He experimented for a year without much success but gained the attention of investors. Hall co-founded the Pittsburgh Reduction Company in 1888 and initiated production of aluminium. Hall's patent was granted in 1889. In 1889, Hall's production began to use the principle of internal heating. By September 1889, Hall's production grew to 385 pounds (175 kilograms) at a cost of $0.65 per pound. By 1890, Hall's company still lacked capital and did not pay dividends; Hall had to sell some of his shares to attract investments. During that year, a new factory in Patricroft was constructed. The smelter in Lockport was unable to withstand the competition and shut down by 1892. The Hall–Héroult process converts alumina into the metal. Austrian chemist Carl Josef Bayer discovered a way of purifying bauxite to yield alumina in 1888 at a textile factory in Saint Petersburg and was issued a patent later that year; this is now known as the Bayer process. Bayer sintered bauxite with alkali and leached it with water; after stirring the solution and introducing a seeding agent to it, he found a precipitate of pure aluminium hydroxide, which decomposed to alumina on heating. In 1892, while working at a chemical plant in Yelabuga, he discovered the aluminium contents of bauxite dissolved in the alkaline leftover from isolation of alumina solids; this was crucial for the industrial employment of this method. He was issued a patent later that year. The total amount of unalloyed aluminium produced using Deville's chemical method from 1856 to 1889 equaled 200 metric tons. Production in 1890 alone was 175 metric tons. It grew to 715 metric tons in 1893 and to 4,034 metric tons in 1898. The price fell to $2 per pound in 1889 and to $0.5 per pound in 1894.
By the end of 1889, a consistently high purity of aluminium produced via electrolysis had been achieved. In 1890, Webster's factory went obsolete after an electrolysis factory was opened in England. Netto's main advantage, the high purity of the resulting aluminium, was outmatched by electrolytic aluminium and his company closed the following year. Compagnie d'Alais et de la Camargue also decided to switch to electrolytic production, and their first plant using this method was opened in 1895. Modern production of the aluminium is based on the Bayer and Hall–Héroult processes. It was further improved in 1920 by a team led by Swedish chemist Carl Wilhelm Söderberg. Previously, anode electrodes had been made from pre-baked coal blocks, which quickly corrupted and required replacement; the team introduced continuous electrodes made from a coke and tar paste in a reduction chamber. This advance greatly increased the world output of aluminium.
== Mass usage ==