The earliest understanding of aluminum began in17th century. German chemist Shtal first noticed that alum [K2SO4 Al 2 (SO4) 3 24h2o] contains a substance completely different from ordinary metals. His student Magraff (1709 ~ 1782) separated alumina from alum in 1754 and determined that it was different from calcium oxide.
After Volta, an Italian physicist, invented the battery, during the period of 1808 ~ 18 10, both British chemist David and Swedish chemist Bezirius tried to separate aluminum from bauxite by current, but both failed. On the other hand, Bezirius first named this unattainable metallic aluminum. This is from Latin alumni. In medieval Europe, this word was a general term for polymerized alum. Today, the Latin name of aluminum is translated from the name of Bezirius. We transliterated from its second syllable to aluminum.
By 1825, Danish chemist Oster (H.C.Oersted, 1777 ~ 185 1) tried to replace aluminum chloride with its stronger chemical activity. He passed chlorine gas through a mixture of red-hot charcoal and alumina to get aluminum trichloride (AlCl3), then mixed aluminum chloride with potassium amalgam (alloy) and heated it to get potassium chloride (KCl) and aluminum amalgam. Then the aluminum amalgam is distilled under the condition of air isolation to remove mercury, and the metal with metallic luster similar to tin is obtained. Although the product contains impurities, metallic aluminum was born after all.
1827, german chemist weller (F.W? Hler, 1800 ~ 1882) repeated Oster's experiment. After aluminum trichloride is prepared, aluminum chloride and metal potassium are mixed, placed in a platinum crucible, sealed tightly, and heated to produce a fierce reaction to obtain gray aluminum powder.
1854, the French chemist H.S.C.Deville (1818 ~1881) reduced aluminum chloride with sodium instead of potassium to produce metallic aluminum and cast it into aluminum ingots.
In the following period, aluminum was a precious commodity in jewelry stores and a treasure enjoyed by emperors and nobles. French emperor Charles Louis Napolé on Bonaparte used aluminum forks at banquets; The king of Thailand used an aluminum watch chain. 1855 At the World Trade Fair held in Paris, a small piece of aluminum was placed next to the most precious jewelry, and its label read: Silver from clay. Until 1884, the monument of Washington, the first president of the United States (1732 ~ 1799) was completed, and a 6-pound decorative pyramid made of aluminum was erected at the top of the monument. In 1889, the London Chemical Society also presented Russian chemist Mendeleev with vases and cups made of aluminum and gold.
1886, two young chemists, American Hall (C.M.Hall, 1863 ~ 19 14) and French Elu (P.L.T.Héroult,1863).
Cryolite, whose scientific name is sodium fluoroaluminate, exists in nature, but it is usually made of aluminum hydroxide [Al (OH) 3], sodium carbonate (Na2CO3) and hydrofluoric acid (HF). It plays a role in electrolytic alumina. Because alumina is very stable, direct melt electrolysis needs a high temperature above 2050℃, but after adding cryolite to alumina, it can be melted and electrolyzed at about 950℃.
Hall's experiment was conducted between 1884 and 1886. At that time, he was a student in the chemistry department of Oberlin College in Oberlin, Ohio.
Hall's success was encouraged and helped by his teacher Jouett, a professor of chemistry and mineralogy, and his sister Julia Hall. Jouett went to Germany to study chemistry with Weller. In the lecture, Weller mentioned the experiment of making aluminum, encouraged students to find cheap ways to reduce aluminum, and instructed Hall to carry out chemical experiments. Julia Hall, whose younger brother graduated from the chemistry department of Oberlin College, helped Hall set up a simple laboratory in their home, helped Hall to carry out chemical experiments and kept his experimental notes. Obviously, Hall's persistent experiment and indomitable spirit are the key to his success.
Hall initially repeated the previous method of making aluminum, and only after the failure did he consider using electricity to reduce aluminum in the compound. He didn't choose alumina because he knew it was difficult to melt.
The electrolysis experiment needs a battery first. In the 1980s, in a small city like Oberlin, we had to assemble our own batteries. He first electrolyzed the aqueous solution of aluminum fluoride (AlF3), and got hydrogen and aluminum hydroxide without any trace of aluminum. He chose aluminum fluoride instead of aluminum chloride used by predecessors, which is an innovation. Aluminum fluoride is more difficult to prepare than aluminum chloride. Hydrofluoric acid is used, which is highly toxic and corrosive and can corrode glass. It can't be put in a glass bottle like hydrochloric acid and sulfuric acid, but in a container made of lead. He successfully prepared aluminum fluoride, which broke through a difficult point in the experiment and gave him the courage to continue the experiment.
After the failure of electrolytic aluminum fluoride aqueous solution, Hall considered electrolytic melting aluminum fluoride. Considering that it must have a high temperature, ordinary coal stoves can't meet this requirement, so he had to assemble a gasoline-burning stove. Even so, he failed to keep aluminum fluoride in a molten state. The original freezing point of aluminum fluoride is 65438 0.2965438 0℃.
In order to solve the problem of maintaining the molten state of electrolytic substances, this forced him to look for cryolite to help melt, so he began to manufacture it. 1886 On February 9th, he conducted the first experiment on the mixed melt of electrolytic aluminum oxide and cryolite, and conducted another experiment the next day, but no effect was seen. Six days later, on February 16, he experimented again, and his sister was also present. He used a graphite rod as an electrode and immersed it in a clay crucible containing a mixture of molten alumina and cryolite. After the current is switched on, gray deposits appear on the cathode instead of flashing aluminum. Hall believes that this gray deposit comes from silicon in clay silicate. So Hall changed into a graphite crucible and experimented again on February 23rd, 1886. When the current was turned on for several hours, silver beads appeared on the cathode, which were confirmed to be aluminum after inspection with hydrochloric acid. He immediately sent the product to his teacher, Jouett, and it was confirmed to be aluminum. Hall is successful.
Immediately after his success, Hall wrote a letter to his brother George Hall, who was an official, and reported his findings. On February 24, he sent a second letter, detailing the relevant technical information he found. These letters later proved that he gave priority to the legal recognition of electrolytic aluminum.
Hall tried to apply his discovery to industrial production, but at first he met with difficulties. Until the summer of 1888, I got a sum of money from A.Hunt, the founder and engineer of Pittsburgh reduction company. I got the help of A.V.Davis in production technology, and I got a generator driven by a steam engine. Finally, 165438 was obtained in 1888. 1April 2, 889 Pittsburgh reduction company was renamed Alcoa. By 1907, Alcoa has owned several mines and three aluminum plants producing alumina. With the continuous increase of aluminum products, the price of aluminum has been falling.
Hall 1885 graduated from university. From 65438 to 0890, he became a member of the American Society of Mining, Metallurgy and Petroleum Engineering. 19 1 1 year, American Chemical Society and Chemical Engineering Society jointly awarded him a medal in recognition of his valuable contribution to applied chemistry. Unfortunately, 19 14 12.27 died of leukemia at the age of 5 1. He never married, leaving 5 million dollars to his alma mater Oberlin College, and building an auditorium on campus in memory of his mother. Now, the full-length statue of Young Hall made of aluminum still stands on the campus of Oberlin College for future generations to enjoy.
Hall succeeded, and so did Elu. At that time, Eru was a student of the Institute of Mining in Paris, France, and also engaged in the research of aluminum production. He was also encouraged and guided by his teacher, French chemist H.L. Le Chatelier (1850 ~1936). 1On April 23rd, 886, Elu obtained a patent for aluminum production approved by France, which triggered the conflict between Hall and Elu's aluminum invention patent. The American court ruled that Hall had priority in 1893, because he found it on February 23rd, 1886, two months before Eru. When Elu went to the United States, it happened that Hall accepted the medal awarded by the American Chemical Society and other groups and was invited to attend the ceremony. The two met and congratulated each other. This is very worthy of congratulations. It was the two of them who passed this piece of "silver" from the soil from the hands of emperors and nobles to the hands of thousands of people in Qian Qian all over the world.
During the First World War, alloys of aluminum and copper, manganese and magnesium appeared and were used in various industrial production. By 1930, aluminum alloy was used in aircraft manufacturing. Today, aluminum pot, aluminum pot and other aluminum products have been widely used in thousands of households. According to foreign statistics, in 1995, the per capita aluminum consumption in the United States reached 19.2 kg, that in China was10.5 kg and that in India was 0.6 kg.