Copper is a transition element with chemical symbol Cu and atomic number 29. Pure copper is a kind of soft metal. When it is just cut, its surface is reddish-orange with metallic luster, and its simple substance is purplish red. Good ductility, high thermal conductivity and electrical conductivity.
Copper is one of the earliest metals used by human beings. As early as prehistoric times, people began to mine open-pit copper mines and use the obtained copper to make weapons, tools and other utensils. The use of copper had a far-reaching impact on the progress of early human civilization.
Copper is a metal that exists in the earth's crust and ocean. The copper content in the crust is about 0.0 1%, and in some copper deposits, the copper content can reach 3% ~ 5%. Most of the copper in nature exists in the form of compounds, that is, copper ores.
Important copper alloys:
1, brass: alloy of copper and zinc, named for its yellow color. It has good mechanical properties and wear resistance, and can be used to manufacture precision instruments, ship parts, artillery shells and so on.
2. Bronze: an alloy of copper and tin, named for its blue color. Generally, it has good corrosion resistance, wear resistance, castability and excellent mechanical properties. It is used to manufacture precision bearings, high-pressure bearings, seawater corrosion-resistant mechanical parts on ships and various plates, pipes and bars.
3. Phosphor bronze: an alloy of copper, tin and phosphorus, which is hard and can be used to make springs.
4, white copper: white copper is an alloy of copper and nickel, its color is the same as silver, silver is shiny, not easy to rust. It is often used to make coins, electrical appliances, instruments and decorations.
5. Octagonal gold (18K gold or rose gold): an alloy of 6/24 copper and 18/24 gold. Red and yellow, high hardness, can be used to make jewelry and decorations.
Extended data
Uses of copper:
1. Transportation equipment is the third largest market for copper, accounting for about 13% of the total.
2. Widely used in manufacturing vacuum devices, distillation tanks, brewing tanks, etc. In the chemical industry.
3. Used for manufacturing bullets, shells, gun parts, etc. In the national defense industry, it takes 13 ~ 14 tons of copper to produce 3 million bullets.
4, in the construction industry, used as various pipes, pipe fittings, decorative devices, etc.
In medicine, copper has a strong bactericidal effect. Mexican scientists also found that copper has anti-cancer function.
6. Copper has a low melting point and is easy to be remelted and smelted, so recycling is quite cheap. In ancient times, it was mainly used for casting utensils, artworks and weapons. Famous vessels and works of art such as stepmother Wu Ding and Siyang Fangzun.
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