Copper is one of the very first metals that man has mastered. In nature, it occurs as large-sized nuggets. Since time immemorial, it has been used as an alloy with tin, called bronze, for the manufacture of weapons, household utensils and jewelry. Such an active use of metal is explained by the ease of processing.
Physical and mechanical properties of copper
Copper is a metal of red-pink color with a golden tint, occupying 29th place in the table of chemical elements and having a density of 8.93 kg / m 3 . The specific gravity of copper is 8.93 g / cm 3 , the boiling point is 2657, and the melting point is 1083 degrees Celsius.
This metal has high ductility, softness and ductility. With a high viscosity, it is excellent forged. Copper is a fairly heavy and durable metal. In its pure form, it conducts heat and electricity well (second only to silver).
Chemical properties of metal
Chemical characteristics, as well as mechanical, magnetic and physical properties, such as ductility, viscosity, specific gravity of copper, are relevant. The metal has a low chemical activity. At low humidity and normal temperature, it has high corrosion resistance. When heated, it oxidizes to form oxides. In a humid environment containing carbon dioxide, the copper surface is coated with a greenish film containing metal oxide and carbonate. Copper reacts with halogens to form salts at room temperature. Easily interacts with sulfur and selenium. It is highly soluble in nitric and heated concentrated sulfuric acid. Without access of oxygen, it does not react with dilute sulfuric and hydrochloric acid.
Copper density
The value of this value contained in the special table is 8.93 * 10 3 kg / m3. The specific gravity of copper is an equally important quantity characterizing a metal. It is, as already mentioned, 8.93 g / cm 3 .
It turns out that the values of the density and specific gravity parameters for a given metal coincide, which is not typical of other materials. The weight of the product made from it depends on the density of the material . To calculate the mass of the future part, specific gravity is usually used, not density.
Specific gravity of metal
This value, as well as density, is an important indicator of various materials, which is determined by the available tables. According to the specific gravity of copper and its alloys, it is possible to select the appropriate metals for the manufacture of a product with specified parameters. Such calculations are usually carried out at the design stage. Specific gravity as a physical quantity is calculated by the ratio of the weight of a substance to its volume. This value should not be confused with density, like mass with weight. Knowing the specific gravity of copper or alloy, you can always calculate the mass of a product from a given material.
The main copper alloys used in industry
According to the manufacturing process, copper alloys are divided into cast and wrought alloys, and depending on the chemical composition - into bronzes and brass. The last base is copper and zinc, and other elements can be added. Bronze is an alloy of copper (specific gravity 8.93 g / cm 3 ) with other metals. The choice of alloying component depends on the specific use of the product.
According to the content of the main component, copper casting is of the following types:
- Tin bronze. During production, hardening and aging are used to increase ductility and strength.
- Aluminum bronze. It has anticorrosive properties, excellent deformation.
- Lead alloy. It has excellent anti-friction properties.
- Brass. May consist of two or more components.
- A copper-nickel alloy containing zinc. It resembles cupronickel in properties and appearance.
- Alloy of copper with iron. Its main difference is high porosity.
The proportion of electrical copper
Such it is obtained after purification from impurities. The smallest content of any metals in it significantly reduces its electrical conductivity. So, for example, the content of 0.02% aluminum reduces the conductivity to 10%, despite the fact that this metal conducts electric current well. The most important material characteristics are:
- specific gravity of copper;
- electrical resistance;
- the melting temperature.
For the needs of electrical engineering, technically pure metal is used, which contains from 0.02 to 0.04% oxygen, and products with high current conductivity are made from special, oxygen-free copper. Different types of metal are used for electrical products (transformer windings, wires, cable conductors, electrical busbars).
The use of copper and its alloys in the national economy
High strength, specific gravity of copper, excellent electrical conductivity, good mechanical workability - all this allows its use in many areas of production:
- Construction - perfectly combined with brick, wood, glass, stone. It has a long service life, is not afraid of corrosion.
- Electrical - wires, cables, electrodes, tires.
- Chemical - make parts for equipment and tools.
- Metallurgical - alloy production. The most sought after is brass. It is harder than copper, forges well, has viscosity. Various shapes are stamped from it and rolled into thin sheets.
- Artistic - copper coinage, bronze statues.
- Household - use for making dishes, pipes.
Copper ore
Under natural conditions, copper is most often found in compounds, but it also occurs in the form of nuggets. Minerals, which are its main sources, include:
- Cuprite is a mineral of the oxide group.
- Malachite - known as an ornamental stone, contains copper carbonate. Russian malachite - carbonic copper greens is very popular.
- Azurite is a blue colored mineral, often spliced with malachite, and has high hardness.
- Copper pyrite and copper luster - contain copper sulfide.
- Covellins - refers to sulfide rocks, was originally discovered near Vesuvius.
Copper ores are mined mainly by open pit mining. They may contain 0.4-1.0% copper. Chile is the world leader in its production, followed by the United States of America, Russia, Canada, and Kazakhstan.