Copper industry knowledge: the role of copper
Copper is a chemical element. Its chemical symbol is Cu (Latin Cuprum). Its atomic number is 29. It is a transition metal. Copper is a purple-red metal with a density of 8.92 g/cm3. Its melting point is 1083.4±0.2℃ and its boiling point is 2567℃. Common valences are +1 and +2. Its ionization energy is 7.726 electron volts.
Basic Introduction to Copper
Copper is the earliest metal used by humans. As early as prehistoric times, people began to mine open-pit copper mines and use the copper they obtained to make weapons, tools and other utensils. The use of copper had a profound impact on the progress of early human civilization. Copper is a metal that exists in the earth's crust and the ocean. The content of copper in the earth's crust is about 0.01%. In some copper deposits, the content of copper can reach 3% to 5%. Most of the copper in nature exists as compounds, namely copper minerals. Copper minerals aggregate with other minerals to form copper ore. The mined copper ore becomes copper concentrate with a higher copper grade after beneficiation.
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Main chemical properties of copper
Copper does not oxidize in dry air, but forms a layer of verdigris on the surface in wet air containing carbon dioxide; it reacts very slowly with alkaline solution, but easily forms a complex with ammonia. Copper cannot replace hydrogen in acid solution, but dissolves in oxidizing acid. The standard electrode potential of copper is +0.337 volts, and the electrochemical equivalent of divalent copper is 1.186 g/(ampere-hour).
Uses of copper
Throughout history, copper has been a widely used nonferrous metal. In 1998, the world's copper production was 14 million tons, ranking second among nonferrous metals. It is predicted that the U.S. copper consumption in 2000 will be 3.505 million to 5 million tons, of which the electrical industry accounts for 71.4%, construction equipment accounts for 10.3%, mechanical equipment accounts for 9.1%, transportation equipment accounts for 4.1%, military supplies account for 1.1%, and decoration, pigments, currency, etc. account for 4.0%.
Wires made of copper's good conductivity are widely used in the power and electronics industries as input wires. High-purity copper containing more than 99.99% copper is used to manufacture highly conductive copper wires and parts that need to be conductive. The integrated circuits of electronic computers and printed circuit boards of large-scale integrated circuits are made of composite boards of copper plated on polymer materials. Copper can also be made into high-temperature resistant aerospace wires.
Copper can also be made into various copper alloys. According to the traditional classification method, it can be divided into four categories: red copper, brass (copper-zinc alloy), white copper (copper-nickel alloy) and bronze (copper-tin alloy). It is mainly used for electrical conductivity, thermal conductivity, elasticity, corrosion resistance, decorative coinage, etc.
Copper has many compounds, but its usage is very small, accounting for only about 1% of copper consumption. It is mainly used in chemical industry, medicine, pesticide, metallurgy, etc. For example, copper sulfate (CuSO4·5H2O) is mainly used as raw material for electroplating copper and various copper salt production, chemical catalyst, activator for mineral flotation, disinfection of medicine and pesticide, insecticide, and animal feed additive.
