Copper mining: methods, enrichment and application

A shiny pink metal with high ductility – that’s what copper is. The mineral is characterized by high electrical and thermal conductivity, lends itself well to mechanical processing and forms many compounds with other metals, which are quite widely in demand in human economic activity. In addition, copper is highly resistant to corrosion.

Copper production

Pyrometallurgical method

Hydrometallurgical method

Electrolysis method

Areas of use

Deposits in Russia and the world

World reserves

Copper mining countries

Its density is 8890 kg/m3.

The melting point is 10830C.

Varieties of copper ores

There are nine geological types of copper ores of industrial importance:

Iron-nickel ores occurring in igneous rocks.
Cuprous sandstones and shales. Stratiform reserves account for 30% of copper reserves and therefore occupy second place in this list.
Copper-nickel. The deposits are distinguished by a variety of shapes with large inclusions of the desired metal.
Porphyry copper. They are the undisputed leader and provide 40% of global copper production.
Carbonatite. They are unique in that there is only one deposit in the world; in addition, they contain alkaline compounds.
Quartz-sulfide. They do not play a significant role in ensuring production.
Native. They are located in oxidation areas of copper-sulfide ore mines.
Skarn. They are located among limestones and are characterized by extreme heterogeneity of morphological structure.

Copper in the listed list of ores can be presented in sulfide, oxide or mixed form, which determines the corresponding types of deposits. Based on their structure in rocks, deposits are divided into disseminated, massive and continuous textures. In the near future, this list may be supplemented by ores lying at the bottom of seas and oceans, as well as nodules of uranium deposits.

Use of copper in medicine

Traditional medicine considers copper to be a very important element of human life. In the body, this substance is contained in an amount of 2 * 10-4% of the total mass. Every day a person consumes up to 60 mg of copper with food, of which approximately 2 mg is absorbed, which is the necessary norm for a healthy body. Copper plays an important role in the biosynthesis of hemoglobin, in maintaining the levels of sugar, cholesterol and uric acid. Copper is necessary for the normal functioning of the cardiovascular system, brain, and digestive tract. In case of its deficiency, the following develops:

anemia;

Use of copper in medicine
osteoporosis;
glaucoma;
psoriasis;
bronchial asthma;
neuritis;
atrophy of the heart muscle;
fatigue;
weight loss;
accumulation of cholesterol.

Use of copper in medicine:

For the treatment of acute deficiency, medications containing this microelement are used;
in therapy - the use of metal applications or bracelets.

The largest amount of microelement is found in foods such as:

Champignon;
potato;
Cod liver;
whole grain;
oysters and cuttlefish.

At the same time, excess copper in the body, when its amount exceeds 250 mg, leads to intoxication and disruption of the liver, the development of Wilson's disease, and anemia.

Natural minerals containing copper

There are 250 copper-containing minerals in nature, but no more than 20 are used in practice. A list of the most common of them, indicating the percentage of copper:

Native copper – 88-100%.
Cuprite – 88.8%.
Tenorit – 79.9%.
Khalzokin – 79.8%.
Covelline – 66.5%.
Bornite – 52-65%
Atakamit – 59.5%.
Malachite – 57.4%.
Brochantite – 56.2%.
Azurite – 55.3%.
Fahl ores – 22-53%.
Enargit – 48.3%.
Chrysocolla – 32.8-40.3%.
Chalcopyrite – 34.5%.
Cubanite – 22-24%.

Application and marking of copper

To find out the specific composition, according to the GOST 859-2001 classification, there is a special table with characteristics and markings. The most in demand is cathode copper or copper semi-finished products, in other words, wire rod, rolled products, ingots and items made of copper alloys. The features and scope of use of the metal, according to the GOST 859-2001 table, are determined according to the percentage of various impurities. Different brands of copper contain from 10 to 50 different impurities. Most often there is a division into two groups:

an alloy that contains a minimal amount of oxygen (up to 0.011%). This alloy has high purity. Designation according to GOST 859-2001 – M00, M01, copper M3. Used mainly to create conductors or high-purity alloys
a refined metal containing an admixture of phosphorus for general use. Designations according to GOST 859-2001 – M1f, M2r, M3r. This metal is used to create pipes, hot-rolled and cold-rolled sheets, and foil.

It is worth noting that the classification data according to GOST 859-2001 corresponds to foreign classification data according to DIN. In a foreign classification, chemical elements and impurities must be designated. For example, grade M00 is CuOFE, M1 is CuOF. For the cryogenic industry, only the purest metals, oxygen-free grades, are used. For all other needs, the most popular are the following types of hot and cold rolled products, which are used in a variety of construction and manufacturing sectors:

M0, M00 – used to create electrical conductors and high-frequency products. They are made only to order and are more expensive.
M001b, M001bf - they are used to make small-section copper wire, electrical busbars, wiring
M1 copper (M1r, M1re, M1f) are excellent current conductors, rolled materials and high-quality bronzes with the lowest possible amount of tin. Such copper is used to create rods and electrodes for electric welding of cast iron and other poorly weldable metals
copper M2 (M2k, M2r). It is suitable for creating products for cryogenic technology, cast products for pressure processing.
M3 copper (M3r, M3k) is used in the process of creating pressed semi-finished products and flat products. In addition, it is used to make wire for electromechanical welding of copper and cast iron objects.

Copper ore mining

Copper is one of the very first metals mastered by mankind. At the very beginning, it was mined by collecting nuggets, and then they learned to extract it from ores. Over the years, mining technologies have improved. But the determining factor when choosing a mining method has always been and is the depth of the deposits. However, there are specially developed standards that take into account many factors and allow you to choose the most successful solution from an economic point of view, in terms of choosing the working depth of development and the technologies used.

In career

If the seam of the mineral being developed is located at a depth of no more than 500 m, the most appropriate is the open-pit mining method. It is with its help that most copper ores are extracted. Despite a number of problems associated with the development of a large area, the movement of huge masses of waste rock, the use of a significant amount of technical equipment and the harmful impact on the environment, the method is characterized by fairly high efficiency and the absence of significant losses of minerals. The ratio of metal yield to mined ore is: 1:200.

After conducting preliminary geological studies at the site of the future quarry or open-pit mine, the upper layers of rock are removed and disposed of in dumps. Very often this is accompanied by drilling of solid rock masses and blasting operations. The fossil mineral is extracted in layers with the further development of new massifs. Ore is picked up by bucket equipment (excavators, loaders) and loaded onto vehicles (conveyors, dump trucks) for transportation to processing plants.

In the mines

If the desired ore is located at a depth of about 1 km, then a closed mining method is used, that is, the construction of a mine and the organization of vertical, inclined or horizontal workings. Using mining equipment and drilling equipment, copper-bearing layers are developed. After which the extracted rock is loaded and removed to the surface. For this purpose, underground structures are equipped with elevators, lifting equipment, and railway tracks.

Copper

The method is quite expensive, but at the same time it provides access to deep-seated deposits.

Drilling of the wells

There is a third method for extracting copper ores - by pumping leaching solutions of acids and alkalis deep into a pre-drilled well. The result is a semi-liquid mixture, extracted to the surface by powerful pumps and subjected to further processing.

PROPERTIES

Native copper crystals, Lake Superior, Kinawee County, Michigan, USA. Size 12 x 8.5 cm

Copper is a golden-pink ductile metal; in air it quickly becomes covered with an oxide film, which gives it a characteristic intense yellowish-red hue. Thin films of copper have a greenish-blue color when exposed to light.

Along with osmium, cesium and gold, copper is one of the four metals that have a distinct coloration that is different from the gray or silver of other metals. This color tint is explained by the presence of electronic transitions between the filled third and half-empty fourth atomic orbitals: the energy difference between them corresponds to the wavelength of orange light. The same mechanism is responsible for the characteristic color of gold.

Copper has high thermal and electrical conductivity (it ranks second in electrical conductivity among metals after silver). Specific electrical conductivity at 20 °C: 55.5-58 MS/m. Copper has a relatively large temperature coefficient of resistance: 0.4%/°C and is weakly dependent on temperature over a wide temperature range. Copper is diamagnetic.

There are a number of copper alloys: brass - with zinc, bronze - with tin and other elements, cupronickel - with nickel and others.

Copper production

After mining the ore, the next problem arises: how to extract the necessary material from it? There are several ways.

One of the oldest technologies involved burning malachite ores with limited air access. The mass placed in pots, mixed with coal, burned, releasing carbon monoxide. Which led to achieving the desired result - obtaining copper that was sufficiently pure for its time.

It is clear that over the past centuries, methods and methods of ore processing have undergone major changes, driven by the goal of achieving the most optimal results for any type of primary raw material. That is why modern metallurgy is based on three main methods for producing copper.

Pyrometallurgical method

Based on high-temperature processes, the pyrometallurgical method is ideally suited for sulfide ores, which are sometimes quite poor in copper concentration. It allows you to extract metal even with a content of 0.5%.

But first of all, the feedstock is enriched during the flotation process. Its essence lies in thoroughly grinding the ore, filling it with water, and adding complex organic flotation reagents. They envelop mineral particles containing copper alloys, giving them non-wetting.

At the second stage of this process, foam is created in the solution, the bubbles of which pick up particles coated with organic matter. This happens under the influence of air flow, as a result of which the formations float to the surface, from where they are later taken up. The foam saturated with copper compounds is collected, squeezed out and dried.

After which the resulting concentrate is fired at a temperature of 14,000 C. This is necessary to remove sulfur and oxidize sulfides. Then high-temperature (14,0000 - 15,0000C) smelting is carried out in shaft furnaces to produce an alloy of iron and copper - matte. Next, in the process of Bessemer smelting in a converter under the influence of oxygen, the oxide is obtained, and then the blister copper itself, containing 90.95% of the metal. In this case, sulfur turns into an acid residue, and iron into silicate slag.

You can obtain pure copper from a rough substance using:

fire refining,
electrolysis,
exothermic reduction reaction under the influence of hydrogen.

Hydrometallurgical method

To extract copper and a number of other metals from polymetallic ores containing less than 0.5% of the desired mineral, the hydrometallurgical method is used.

The extracted minerals are dissolved using non-concentrated sulfuric acid or ammonia. Copper is obtained from the resulting liquids during the displacement reaction. Metallic iron is used to carry out the reaction.

Electrolysis method

The method is designed to obtain pure copper through an electrolytic reaction.

Its technology is to produce pure copper thin sheet cathodes and thick plate anodes from blister copper. Placed then in a bath filled with copper sulfate, they react under the influence of electric current. Copper dissolves on the anodes and is deposited on the cathodes. Released impurities are removed by chemical methods.

Copper pipes

Alloys

Pure copper is not always used in industry. To change the technical characteristics of non-ferrous metal, various components are added to it. The result is alloys that have a copper base. The most common:

Bronze - Made by adding tin.
Brass is made from a copper base to which zinc is added.

These are not all compounds where copper is the main component.

Bronze figurine

Areas of use

There are many industries where this oldest of metals finds its application:

Metallurgy. It is this industry that produces many finished products in the form

rolled products: sheets, plates, strips, pipes, rods, tires, wire;
alloys: bronze, brass, cupronickel, constantan, nickel silver manganin.

Both products and intermediate materials are widely used in technical industries, in the production of weapons, and in the arts and crafts. The distinctive features of the alloys are the preservation of mechanical properties, a high level of slip in a paired combination and anti-corrosion resistance.

Mechanical engineering. A significant portion of copper-containing products obtained as a result of metallurgical processes is used here. These are high-strength alloys with aluminum, tin, silicon, and zinc. As well as various parts of machines and mechanisms. One of the directions is the production of hard solders, which again find application in the mechanical engineering industry.
Chemistry. The catalyst for the polymerization of acetylene is again copper.
Electrical engineering. Due to its high electrical conductivity, this metal has become indispensable as a conductor in the manufacture of buses, cables, wires, and printed circuit board tracks. They, in turn, are part of many electrical products, which also contain copper structural elements and alloys of this metal. In addition, copper is used in chemical current sources and in the manufacture of high-temperature superconducting materials.
Energy. One of the important areas of using copper is the production of pipes based on it, which are an integral part of gas supply systems, water supply, heating, cooling, air conditioning and supply of process fluids.
Jewelry making. The specifics of manufacturing precious items that serve as jewelry require a combination of a number of contradictory factors. To give strength to gold, copper is added to it. The pliability of the material does not decrease, but the service life and resistance to mechanical stress increase significantly.

History of discovery

The most ancient copper products were found in the territory of modern Turkey. They were located in the ruins of the settlement of Çatalhöyük. After the Stone Age came the Copper Age. Scientists in the 20th century were able to prove that with the help of tools made of copper, materials can be processed faster.

Alloys with tin, called bronze, were made from copper. They were used to create jewelry, tools, and weapons. When bronze gained great popularity, the Bronze Age began, which replaced the Copper Age.

The first large mines were found in Cyprus. They were developed around 3000 BC. e. In Russia, the oldest mines date back to 2000 BC. e.

Industrial smelting of copper ingots was developed in the 13th–14th centuries. In Moscow in the 15th century, the Cannon Yard was founded, which produced guns and ammunition from bronze.

Deposits in Russia and the world

On the territory of Russia there are many fairly large deposits of copper ore:

Allarechenskoye, Monchegorskoye, Pechenga - Murmansk region.
Gayskoye - Orenburg region.
Mikheevskoye, Tominskoye – Chelyabinsk region
Yubileiny, Sibayskoye, Podolskoye, Zapadno-Ozernoye, Uchalinskoye, Novo-Uchalinskoye, Oktyabrskoye - Republic of Bashkortostan.
Bystrinskoye and Udokanskoye - Transbaikalia.
Oktyabrskoye, Talnakhskoye - Krasnoyarsk Territory.

The following deposits of this mineral are highlighted on the world map:

Chuquicamata, Escondida, Collahhuasi, Antamina, El Tesoro - Chile.
Bingham Canyon, Keweenaw, Pebble - USA.
Vale Salobu - Brazil.
Nurkazgan - Kazakhstan.
Uyu Tolgoi - Mongolia.
Grazberg - Indonesia.

Copper mining countries

The leading positions in global copper production (2022 data in quantitative terms of the metal mined per year) are occupied by:

Chile – 5.8 million tons.
Peru – 2.4 million tons.
China – 1.6 million tons.
USA – 1.2 million tons.
Congo - 1.2 million tons.

Judging by expert estimates, the total volume of as yet unexplored copper reserves in the world is 3.5 billion tons. These reserves should be enough for the next century and a half.

Author: Yuri Florinskikh All articles by this author

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