How is copper mined?

What is copper ore, how is it mined, processed and what is it used for?

There are not many metals on our planet whose production volumes exceed those of copper. The twenty-ninth number in Mendeleev’s periodic table is in honorable third place in terms of production levels, right after iron and aluminum. Too many industries would be in trouble if their storerooms suddenly ran out of much-needed metal. The importance of copper and copper ore can hardly be overestimated for electrical engineering, heating engineering, metallurgy, medicine and even transport.

How copper differs from other metals and how copper is mined will be discussed below.

What is copper ore

Copper ore, like any other, is a conglomerate of substances, rocks, minerals, the content of the desired substance in which is so high that it is considered appropriate for mining. It is worth saying that along with the so-called Cuprum (the Latin name for copper), other useful elements are also mined in its ore in even smaller proportions. Copper itself begins to be mined in ores in which its amount exceeds 0.5%.

Yes, in its pure form, copper is found in nature even more often than aluminum, but still this figure is approximately one percent of the global reserves, because mining is still carried out from ores. The following groups of ores are distinguished by places of formation and composition: carbonate, sulfide, copper-nickel, porphyry copper (hydrothermal), skarn, stratiform.

Differences in saturation

There are a lot of variations of copper compounds with other substances in ores, about two and a half hundred. We will look at the most popular and most intense:

1. Bornite. Most often it belongs to the hydrothermal group of ores and may contain about 65% Cuprum. Chem. formula – Cu5FeS4;
2. Kovelin. Also a member of the hydrothermal group, up to 64% copper. Formula – CuS;
3. Chalcopyrite. Hydrothermal group. Copper saturation is 30%. The most popular ore is 50% of all deposits. Formula – CuFeS2;
4. Chalcocine. Leader in terms of saturation. 79.8% “red metal”. Still the same hydrothermal group. Formula – Cu2S.

Copper ore mining methods

There are two methods of mining - mine and open pit. That's all that modern technologies can boast of during ore mining. The open method is used in cases where the copper deposit is not located very deep underground (about 400-500 meters). First, a layer of waste rock is removed, and then the mining process itself begins, to facilitate which directed explosions are used.

Source: https://geomix.ru/blog/gornoe-delo/mednaya-ruda/

Copper ore - deposits, mining, types, processing

The most common copper ore on our planet is bornite. But besides it, copper is also mined from other ores, which we will talk about in this article.

Copper ore: properties and characteristics

Copper is a plastic element with a golden-pink hue. In the open air, the metal is immediately covered with an oxygen film, which gives it a specific red-yellow color.

Characteristic properties: corrosion resistance, high thermal and electrical conductivity.

At the same time, the element has high antibacterial properties and destroys influenza viruses and staphylococci.

In the industrial complex, copper is most often used in alloys with other components: nickel, zinc, tin, gold, etc.

: Copper - melting point, physical properties, alloys

Mineral base for metal extraction

The raw materials for copper ore mining are natural mineral formations in which the metal component is contained in quantities necessary for economically viable industrial development.

Raw materials for copper ore mining.

Ore deposits are represented by silicate, carbonate, sulfate compounds, and oxides formed in the oxidation zone.

Among the explored minerals for industrial development are:

• chalcopyrite;
• chalcocite;
• bornite;
• cuprite;
• native copper;
• brochantite;
• azurite;
• cubanite;
• malachite;
• chrysotile.

In ore, the metal concentration is 0.3–5%, and in minerals the concentration is 22–100% (native metal). Copper deposits are in a genetic relationship with other valuable components that are mined as additional chemical elements to the main process.

Among the associated components are:

• platanoids;
• silver;
• gold;
• tellurium;
• gallium;
• molybdenum;
• bismuth;
• nickel;
• titanium;
• zinc.

The ore for copper extraction contains arsenic, antimony, and less commonly mercury. Depending on the type of associated chemical elements, types of deposits are distinguished, among which the main ones are:

• copper-nickel;
• copper-pyrite;
• cuprous sandstones and shales;
• copper-porphyry.

Skarn metal deposits and quartz-sulfide formations are of subordinate importance. In the future, ferromanganese nodules found in the bottom sediments of the World Ocean are considered as raw materials for industrial metal production.

Copper ore deposits

Copper ores are a collection of minerals that, in addition to copper, contain other elements that shape their properties, in particular nickel.

The copper ore category includes those types of ores that contain such an amount of this metal that it is economically feasible to extract it by industrial methods. These conditions are satisfied by ores whose copper content is in the range of 0.5–1%.

Our planet has a reserve of copper-containing resources, the bulk of which (90%) are copper-nickel ores.

Most of the copper ore reserves in Russia are located in Eastern Siberia, on the Kola Peninsula, in the Ural region.

Chile is on the list of leaders in total reserves of such ores; deposits are also being developed in the following countries: the USA (porphyry ores), Kazakhstan, Zambia, Poland, Canada, Armenia, Zaire, Peru (porphyry ores), Congo, Uzbekistan.

Experts have calculated that large copper deposits in all countries contain a total of about 680 million tons. Naturally, the question of how copper is mined in different countries must be considered separately.

Covellin

All copper ore deposits are divided into several categories, differing in genetic and industrial-geological characteristics:

• stratiform group represented by copper shales and sandstones;
• pyrite ores, which include native and vein copper;
• hydrothermal, including ores called porphyry copper;
• igneous, which are represented by the most common ores of the copper-nickel type;
• skarn type ores;
• carbonate, represented by ores of the iron-copper and carbonatite type.

In Russia, copper mining is carried out mainly in shale and sand deposits, in which the ore is contained in copper pyrite, copper-nickel and porphyry copper forms.

Bornite

Varieties of copper ores

Ore classification according to genetic and geological characteristics:

• stratiform - these are sandstones and shales;
• pyrite - vein copper and nuggets;
• hydrothermal - it is called the porphyry copper form;
• skarn rocks;
• igneous - this ore contains nickel;
• carbonate - have an iron-copper and carbonatite composition.

Natural compounds containing copper in their composition

Pure copper nuggets are found in our Earth in small quantities. It is mainly mined in combination with other elements, here are the most famous of them:

1. Bornite is a mineral that was named after the Czech scientist Born. It is a sulfide ore. It also has alternative names, such as copper purple. It is mined in two types: low-temperature tetragonal-scalenohedral and high-temperature cubic-hexahedral. The different types of this material depend on where it originated. Exogenous bornite is a secondary early sulfide, is unstable and is subject to destruction when exposed to winds. Endogenous bornite has a variable chemical composition and may contain various elements, for example, chalcocite and galena. In theory, bornite can contain 11% iron and more than 63% copper, but, unfortunately, in practice this composition is not maintained.
2. Chalcopyrite - this type of mineral was originally called copper pyrite; it originates hydrothermally. Chalcopyrite is classified as a polymetallic ore. In addition to copper, this mineral contains iron and sulfur. It is formed as a result of metamorphic processes, and is present in metasomatic types of copper ores.
3. Chalcocine - this ore contains a large amount of copper, almost 80%, the remaining place is occupied by sulfur. This type is often called copper glitter, as its surface is similar to shiny metal, shimmering in several shades. In ores, chalcocite forms as a fine-grained or dense inclusion.
4. Cuprite - this mineral belongs to the oxide group, and it originates in places where native copper or malachite is contained.
5. Covellite is a mineral that is formed only metasomatically. It contains almost 67% copper. There are large deposits of copper ores in Serbia, Italy and the USA.
6. Malachite, or, as it is also called, an ornamental stone, is very popular; it is a copper carbon dioxide green. If this mineral is found somewhere, it means that others containing copper can be found nearby.

: Copper plating at home - chemical, galvanic

Mineral extraction methods

In Russia there are deposits such as shale and sandstone. Copper pyrite, copper-nickel and porphyry copper forms occur here. The mining industry uses various methods to extract minerals from the depths of the earth.

Depending on the depth of occurrence, ore is mined using open or closed methods. There are standards that determine the feasibility of the depth of excavation of soil layers and the use of technologies that reduce their costs.

The work technology includes the following:

• use of self-propelled equipment;
• production of ore extraction directly;
• filling the resulting voids with materials to make further work safe.

With the open method, fossils are selected in layers, this ensures their fullest use. For deep quarries, the technology of cyclic-flow operations is suitable, it depends on the characteristics of the layers.

Negative consequences of mining

When the formations occur at a depth of 500 to 1000 m and deeper, the closed method of copper mining is convenient. This requires vibration mechanisms; the rock is completely excavated and delivered to the surface. The voids formed underground are filled using pipes lined with rubber or basalt resin.

It is economically advantageous to locate the mineral processing industry in close proximity to the places of their extraction. It is also necessary to build plants for recycling waste after processing. This can promote the release of various beneficial products. For example, processing sulfur dioxide makes it possible to obtain useful fertilizers containing sulfur.

Metal extraction technology

To separate rocks that do not contain a valuable component, the flotation method is used. Only a small amount of raw materials containing copper in high concentrations is subjected to direct smelting. Metal smelting involves a complex process that includes the following operations:

• burning;
• fuse;
• conversion;
• fire and electrolytic refining.

Melting of raw materials.

During the roasting process of raw materials, the sulfides and impurities contained in it are converted into oxides (pyrite is converted into iron oxide). The gases released during roasting contain sulfur oxide and are used to produce acid.

Metal oxides formed as a result of the influence of a temperature gradient on the rock are separated in the form of slag during firing. The liquid product obtained from remelting is subjected to conversion.

Valuable components are extracted from blister copper and harmful impurities are removed by fire refining and other metals are removed by saturating the liquid mixture with oxygen and then pouring it into molds. Castings are used as an anode for the electrolytic method of purifying copper.

The raw material, which contains copper and nickel, is subjected to enrichment using a selective flotation scheme in order to obtain a metal concentrate. Iron-copper ores undergo magnetic separation.

Cuprous sandstones and shales, gangue and native metal ores are processed to extract copper concentrate. Enrichment is carried out using the gravitational method.

The flotation method is used for mixed and oxidized ores, but chemical methods and bacterial leaching are more often used.

High copper content is characteristic of concentrates extracted from chalcocite and bornite, and low copper content is characteristic of chalcopyrite.

Concentration of ore with low copper content can be carried out using a hydrometallurgical method, which consists of leaching copper with sulfuric acid. Copper and related metals, including precious ones, are separated from the resulting solution.

Source: https://intehstroy-spb.ru/spravochnik/mednaya-ruda-svoystva-primenenie-dobycha.html

How to mine copper at home - Metals, equipment, instructions

Copper-containing ores are characterized as multi-element. The most common connections are with:

The following may be present in minor concentrations:

• nickel;
• gold;
• platinum;
• silver.

Deposits all over the world have approximately the same set of chemical elements in the ore composition; they differ only in their percentages. To obtain pure metal, various industrial methods are used. Almost 90% of metallurgical enterprises use the same method for producing pure copper - pyrometallurgical.

One of the largest ore mines produces 17 million tons of copper per year

The design of this process also makes it possible to obtain metal from recycled materials, which is a significant advantage for industry.

Since the deposits belong to the group of non-renewable deposits, reserves decrease every year, ores become poorer, and their extraction and production becomes expensive.

This ultimately affects the price of the metal on the international market. In addition to the pyrometallurgical method, there are other methods:

• hydrometallurgical;
• fire refining method.

Stages of pyrometallurgical copper production

General methods for obtaining metal from ore

Industrial copper production using the pyrometallurgical method has advantages over other methods:

• the technology provides high productivity - it can be used to produce metal from rocks in which the copper content is even lower than 0.5%;
• allows you to efficiently process secondary raw materials;
• a high degree of mechanization and automation of all stages has been achieved;
• its use significantly reduces emissions of harmful substances into the atmosphere;
• The method is economical and effective.

Enrichment

Ore beneficiation scheme

At the first stage of production, it is necessary to prepare the ore, which is delivered to processing plants directly from the quarry or mine. Often there are large pieces of rock that must first be crushed.

This happens in huge crushing units. After crushing, a homogeneous mass is obtained, with a fraction of up to 150 mm. Pre-enrichment technology:

• raw materials are poured into a large container and filled with water;
• oxygen is then added under pressure to form foam;
• metal particles stick to the bubbles and rise to the top, and waste rock settles at the bottom;
• Next, the copper concentrate is sent for roasting.

Burning

This stage aims to reduce the sulfur content as much as possible. The ore mass is placed in a furnace where the temperature is set at 700–800°C. As a result of thermal exposure, the sulfur content is reduced by half. Sulfur oxidizes and evaporates, and some of the impurities (iron and other metals) pass into an easily slag state, which will facilitate later smelting.

Roasting ore to reduce sulfur levels

This stage can be omitted if the rock is rich and contains 25–35% copper after enrichment; it is used only for low-grade ores.

Melting for matte

The matte smelting technology makes it possible to obtain blister copper, which varies by grade: from MCh1 - the purest to MCh6 (contains up to 96% pure metal). During the smelting process, the raw material is immersed in a special furnace, in which the temperature rises to 1450°C.

Copper ore processing technology and black copper production

After the mass is melted, it is purged with compressed oxygen in converters. They have a horizontal appearance, and the blowing is carried out through a side hole. As a result of blowing, iron and sulfur sulfides are oxidized and converted into slag. Heat in the converter is generated due to the flow of hot mass; it does not heat up additionally. The temperature is 1300°C.

General scheme of copper smelting

At the output of the converter, a rough composition is obtained, which contains up to 0.04% iron and 0.1% sulfur, as well as up to 0.5% other metals:

• tin;
• antimony;
• gold;
• nickel;
• silver

This rough metal is cast into ingots weighing up to 1200 kg. This is the so-called anode copper. Many manufacturers stop at this stage and sell such ingots.

But since copper production is often accompanied by the extraction of precious metals contained in the ore, processing plants use the technology of refining the rough alloy.

In this case, other metals are released and preserved.

Refining using copper cathode

The technology for producing refined copper is quite simple. Its principle is even used to clean copper coins from oxides at home. The production scheme looks like this:

Refined copper ingots

• the rough ingot is placed in a bath with electrolyte;
• A solution with the following content is used as an electrolyte:
  • copper sulfate – up to 200 g/l;
  • sulfuric acid – 135–200 g/l;
  • colloidal additives (thiourea, wood glue) – up to 60 g/l;
  • water.
• the electrolyte temperature should be up to 55°C;
• Plates of cathode copper are placed in the bath - thin sheets of pure metal;
• electricity is connected. At this time, electrochemical dissolution of the metal occurs. Copper particles concentrate on the cathode plate, and other inclusions settle at the bottom and are called sludge.

In order for the process of obtaining refined copper to proceed faster, anode ingots should be no more than 360 kg.

The entire electrolysis process takes place within 20–28 days. During this period, the copper cathode is removed up to 3–4 times. The weight of the plates is up to 150 kg.

  Is copper magnetic to a magnet?

How it's done: copper mining

During the refining process, dendrites can form on cathode copper - growths that reduce the distance to the anode. As a result, the speed and efficiency of the reaction decreases. Therefore, when dendrites appear, they are immediately removed.

Hydrometallurgical copper production technology

Copper ore may also contain gold

This method is not widely used because it can result in the loss of precious metals contained in the copper ore.

Its use is justified when the rock is poor - it contains less than 0.3% of red metal.

How to obtain copper using the hydrometallurgical method?

First, the rock is crushed to a fine fraction. Then it is placed in an alkaline composition. The most commonly used solutions are sulfuric acid or ammonia. During the reaction, copper is replaced by iron.

Cementation of copper with iron

The solutions of copper salts remaining after leaching undergo further processing - cementation:

• iron wire, sheets or other scraps are placed in the solution;
• during a chemical reaction, iron displaces copper;
• As a result, the metal is released in the form of a fine powder, in which the copper content reaches 70%. Further purification occurs by electrolysis using a cathode plate.

Fire refining technology for blister copper

This method of obtaining pure copper is used when the starting material is copper scrap.

The process takes place in special reverberatory furnaces, which are fired by coal or oil. The melted mass fills the bath, into which air is blown through iron pipes:

• pipe diameter – up to 19 mm;
• air pressure – up to 2.5 atm;
• oven capacity – up to 250 kg.

During the refining process, copper raw materials are oxidized, sulfur burns out, then metals. Oxides do not dissolve in liquid copper, but float to the surface. To remove them, quartz is used, which is placed in the bath before the refining process begins and is placed along the walls.

Copper refining

If the scrap metal contains nickel, arsenic or antimony, the technology becomes more complicated. The percentage of nickel in refined copper can only be reduced to 0.35%. But if other components are present (arsenic and antimony), then nickel “mica” is formed, which dissolves in copper and cannot be removed.

: Copper ores of the Urals

Source: https://spb-metalloobrabotka.com/kak-dobyt-med-v-domashnih-usloviyah/

Minerals: Copper ores

Copper is a ductile metal of golden-pink color, which in its pure form is found in nature more often than nuggets of gold or silver. But copper is mainly mined from copper ores - natural mineral formations. Most copper is found in sulfide ores. In oxidation zones, copper is found in most silicates, carbonates and oxides. Copper is also found in sedimentary rocks: shales and cuprous sandstones.

Modern science knows more than 200 minerals containing copper. In industry, metal extracted from sulfates is most often used, including:

• Chalcocite (79% copper);
• Bornite (up to 65%);
• Chalcopyrite, or copper pyrite (about 35%).

Copper is also contained in copper-nickel compounds. The most famous of them is cubanite (up to 45% copper). Of the oxidized ores, it is worth noting cuprite (88%), malachite (up to 58%), azurite (up to 56%). Sometimes there are deposits of native copper.

Characteristics and types of copper

Copper is one of the first metals that people began to use. The chemical symbol is Cu (cuprum). This metal has high thermal conductivity, corrosion resistance, and electrical conductivity. Copper melts at low temperatures, is excellent for soldering, and the metal is easy to cut and process.

Some copper compounds can be toxic to humans. High levels of copper in water and food can cause liver and gallbladder diseases. Quarries left behind after copper mining become sources of toxins. For example, Berkeley Pit Lake, formed in the crater of a former copper mine, is considered the most toxic lake in the world. But the bactericidal properties of copper are disproportionately higher. It has been proven that copper helps fight influenza viruses and destroys staphylococci.

In industry, copper is rarely used in its pure form. The following alloys have found greater use:

• Brass (an alloy of copper and zinc);
• Bronze (with tin);
• Babbitts (with lead);
• Cupronickel (with nickel);
• Dural (with aluminum);
• Jewelry alloy (with gold).

Copper deposits and mining

The largest copper deposit in the world is located in Chile - the Esconida quarry. Huge deposits of native copper were discovered here.

Other large deposits:

• Mines on the Keweenaw Peninsula (USA, Michigan);
• Chuquicamata mine in Chile (up to 600 thousand tons per year);
• Corocoro mine in Bolivia;
• Gumishevsky mine (Middle Urals, Russia) - now depleted;
• Valley of the Levikha River (Middle Urals, Russia);
• Gabbro massif (Italy).

According to the US Geological Survey, the largest copper deposits belong to Chile. Next come the USA, Russia, Peru and Mexico.

Copper mining methods:

• Open;
• Hydrometallurgical - when copper is leached from the rock with a weak solution of sulfuric acid;
• Pyrometallurgical – consists of several stages (concentration, roasting, smelting for matte, purging and refining).

Careful handling of copper ores

Copper ores are a non-renewable resource, and therefore their development requires careful treatment, both in mining methods and in industrial processing.

Industry is increasingly becoming more demanding of constant volumes of resources received, which leads to their gradual depletion. To do this, it is necessary to more carefully control the extraction of copper ores, along with other non-renewable resources such as oil, natural gas, and use them more carefully and rationally, both in industrial and domestic consumption.

Copper Applications

Copper is one of the most important non-ferrous metals, which has found application in almost all spheres of human activity.

• Electrical industry (wires, wire);
• Mechanical engineering (starter, power windows, radiators, coolers, bearings);
• Shipbuilding (hull plating);
• Construction (pipes, pipelines, roofing and facing materials, bathtubs, faucets, sinks);
• In art (jewelry, statues, coinage);
• In everyday life (air conditioners, microwave ovens, coins, food additives, musical instruments).

Interestingly, the Statue of Liberty is made of copper. Its construction required about 80 tons of metal. And in Nepal, copper is considered a sacred metal.

Source: https://xn----8sbiecm6bhdx8i.xn--p1ai/%D0%BC%D0%B5%D0%B4%D0%BD%D1%8B%D0%B5%20%D1%80%D1 %83%D0%B4%D1%8B.html

How copper is mined: methods, history and deposits

Copper today is a metal in extraordinary demand and widely used both in everyday life and in industry. In nature, Cu can be found both in its pure state and in the form of ore. There are several methods for mining and obtaining copper from source rocks. Moreover, all of them are used quite widely in industry. How copper is mined will be discussed in the article.

A little history

In what area copper began to be mined and used by humans for the first time in ancient times, archaeologists, unfortunately, were unable to find out. However, it is known for certain that it was this metal that people were the very first to process and use in everyday life.

Copper became known to man back in the Stone Age. Some nuggets of this metal found by archaeologists bear traces of processing with stone axes. Initially, people used copper mainly only as jewelry. At the same time, for the manufacture of such products, people in ancient times used exclusively nuggets of this metal that they found. Later, people learned to process copper-containing ore.

Many peoples of antiquity had an idea of ​​how Cu is mined and how it is processed. Archaeologists have found plenty of evidence of this. After man learned to make alloys of copper and zinc, the Bronze Age began. Actually, the name “copper” itself was once coined by the ancient Romans. Such metal was brought to this country mainly from the island of Cyprus. That's why the Romans called it aes cyprium.

Since this metal was once used very widely in everyday life by humans, the technologies for its extraction were, of course, developed quite advanced. Our ancestors obtained copper mainly from malachite ores. A mixture of such material and coal was placed in a clay vessel and placed in a pit. Next, the mass in the pot was set on fire. The resulting carbon monoxide reduced malachite to copper.

Reserves in nature

Where can you mine copper in the wild today? Currently, deposits of this popular metal have been discovered on all continents of the Earth. At the same time, Cu reserves are considered to be practically unlimited.

Geologists nowadays are finding more and more new deposits of pure copper, as well as ores containing it. For example, in 1950, world reserves of this metal amounted to 90 million tons. By 1970, this figure had already increased to 250 million tons, and by 1998 - to 340 million tons.

Currently, it is believed that copper reserves on the planet amount to more than 2.3 billion tons.

Deposits and methods of mining pure copper

As already mentioned, initially people used native copper in everyday life. Of course, such pure copper is still mined today. Nuggets of this metal are formed in the earth's crust as a result of exogenous and endogenous processes.

The largest known deposit of native copper on the planet is currently located in the USA, in the Lake Superior region. In Russia, native copper occurs in the Udokan deposit, as well as in some other places in Transbaikalia.

In addition, the answer to the question of where copper can be mined in Russia in the form of nuggets is the Ural region.

In nature, pure metal of this variety is formed in the oxidation zone of copper sulfate deposits. Typically, nuggets contain about 90-99% copper itself. The rest comes from other metals.

In any case, the answer to the question of how native copper is mined is provided by two main technologies. Such deposits, like ore deposits, are developed using closed mine or open pit methods.

In the first case, technological processes such as drilling and mining are used.

Copper nuggets can weigh a lot. The largest of them were once found on Lake Superior in the United States. The weight of these nuggets was about 500 tons.

We found out where copper is mined in Russia. These are mainly Transbaikalia and the Urals. In our country, of course, very large nuggets of this metal were also found at different times. For example, copper pieces weighing up to several tons were often found in the Middle Urals. One of these nuggets weighing 860 kg is now stored in St. Petersburg, in the Museum of the Mining Institute.

Copper ores and their deposits

At the moment, obtaining Cu is considered economically profitable and feasible even if it is contained in the rock at least 0.3%.

Most often, the following rocks are mined in nature today to extract copper industrially:

• bornites Cu5FeS4 - sulfide ores, otherwise called copper purple or variegated pyrite and containing about 63.3% Cu;
• chalcopyrites CuFeS2 - minerals of hydrothermal origin;
• chalcocite Cu2S containing more than 75% copper;
• cuprites Cu2O, often also found in places of native copper deposits;
• malachites, which are carbonated copper greens.

The largest copper ore deposit in Russia is located in Norilsk. Also, such rocks are mined in large quantities in some places in the Urals, Transbaikalia, Chukotka, Tuva and the Kola Peninsula.

How copper ore deposits are developed

Various types of rocks containing Cu, as well as nuggets, can be mined on the planet using two main technologies:

In the first case, mines are built at the deposit, the length of which can reach several kilometers. To move workers and equipment, such underground tunnels are equipped with elevators and railway tracks. Rock crushing in mines is carried out using special drilling equipment with spikes. Copper ore is collected and loaded to be sent upstairs using buckets.

If the deposits are located no further than 400-500 m from the surface of the earth, they are mined using the open-pit method. In this case, the top rock layer in the field is first removed using explosive devices. Next, the copper ore itself is gradually removed.

Methods for obtaining metal from rocks

We have thus found out how copper, or rather the ores containing it, are mined. But how do enterprises subsequently obtain Cu itself?

There are three main methods for extracting copper from rocks:

• electrolytic;
• pyrometallurgical;
• hydrometallurgical.

Pyrometallurgical flotation method

This technology is usually used to isolate copper from rocks that contain 1.5-2% Cu. Such material is subjected to enrichment by flotation method. Wherein:

• the ore is carefully ground to the finest powder;
• mix the resulting material with water;
• special flotation reagents, which are complex organic substances, are added to the mass.

Flotation reagents coat small grains of various copper compounds and impart non-wetting to them.

At the next stage:

• substances that create foam are added to the water;
• pass a strong air stream through the suspension.

Light dry particles of copper compounds as a result stick to the air bubbles and float to the top. The foam containing them is collected, squeezed out of the water and dried thoroughly. As a result, a concentrate is obtained, from which rough Cu is then isolated.

How copper is extracted from ore: beneficiation by roasting

The flotation method is used quite often in industry. But sometimes roasting technology is also used to enrich copper ore. This technique is most often used for ores containing large amounts of sulfur. In this case, the material is preheated to a temperature of 700-8000 °C. As a result, sulfides oxidize and the sulfur content in the rock decreases.

At the next stage, the ore prepared in this way is melted in shaft furnaces at a temperature of 14500 °C. Ultimately, when using this technology, matte is obtained - an alloy of copper and iron. This connection is further improved by blowing in converters. As a result, iron oxide turns into slag, and sulfur into SO4.

Obtaining pure copper: electrolysis

Using flotation and roasting methods, blister copper is obtained. Actually, such material contains about 91% Cu. To obtain purer copper, rough copper is subsequently subjected to refining.

In this case, thick anode plates are first cast from primary copper. Further:

• take a solution of copper sulfate into the bath;
• hang anode plates in the bathroom;
• Thin sheets of pure copper are used as cathodes.

During the electrolysis reaction, copper dissolves at the anodes, and deposition occurs at the cathodes. Copper ions move towards the cathode, take electrons from it and transform into Cu+2+2e?>Cu atoms.

Impurities contained in blister copper may behave differently during cleaning. Zinc, cadmium, iron dissolve on the anode, but do not settle on the cathode. The fact is that in the series of electrochemical voltage they are to the left of copper, that is, they have more negative potentials.

Copper sulfate is obtained by slow oxidation of sulfide ore with oxygen to copper sulfate CuS + 2O2 > CuSO4. Subsequently, the salt is leached with water.

Hydrometallurgical method

In this case, sulfuric acid is used to leach and enrich copper. As a result of the reaction when using this technology, a solution saturated with Cu and other metals is obtained. Copper is then isolated from it. Using this technique, in addition to blister copper, it is possible to obtain other metals, including precious ones. In any case, this technology is most often used to isolate Cu from rocks that are not too rich in it (less than 0.5%).

Copper at home

Isolation of this metal from ores saturated with it is therefore a relatively simple matter technologically. Some are therefore interested in how to mine copper at home. It will, however, be very difficult to obtain this metal from ore, clay, etc. with your own hands, without special equipment.

Some, for example, are interested in how to extract copper from clay with their own hands. Indeed, in nature there are deposits of this material, which is also rich in Cu. However, unfortunately, there are no known proven technologies for producing copper from clay at home.

You can try to isolate this metal with your own hands at home, perhaps only from copper sulfate. To do this, the latter must first be dissolved in water. Next, you should simply place some iron object into the resulting mixture. After some time, the latter - as a result of the substitution reaction - will be covered with a copper coating, which can then simply be cleaned off.

Source: https://FB.ru/article/464216/kak-dobyivayut-med-sposobyi-istoriya-i-mestorojdeniya

Copper production

The use of copper as a material for the production of tools and weapons has been known to mankind for many centuries.

The development of electrical engineering and electronics was a further stimulus for the development of advanced methods for extracting and processing raw materials in which this metal is present. Modern copper production is a well-established process.

One of the problems in obtaining this scarce metal is the low percentage of copper in the mined ore. It does not exceed five percent of the total amount of mined rock.

Copper production methods

Currently, several methods for producing copper have been developed. The main ones are:

• pyrometallurgy;
• hydrometallurgy;
• electrolysis.

The largest quantity is produced using the first method. With its help, almost 90% of all metal is obtained. It is quite labor-intensive and time-consuming. The technology for producing copper using this method includes several stages that enrich the incoming material and sequentially obtain the finished material. Each stage contains a strict sequence of technological tasks. Typically, a copper smelter performs the full range of operations.

To obtain the so-called copper cathode, a third method is used. This method is completely called electrolytic refining with subsequent deposition of the finished product on the surface of metal plates.

Copper production in Russia and the world

According to analytical agencies, the Russian Federation confidently occupies fifth position among countries engaged in the mining and production of pure copper. Copper production in Russia on average per year is 860 thousand tons.

The basis of the modern structure of copper production is made up of three large holdings: OJSC MMC Norilsk Nickel (Norilsk Nickel), LLC UGMKHolding (UMMC) and CJSC Russian Copper Company (RMK). These companies carry out a full production cycle from ore mining to the production of finished ingots, rolled products and wire.

Each holding includes several enterprises equipped with the most advanced production technologies. Thanks to dynamic development, last year it was possible to increase copper production by seven percent.

Global copper production is fairly consolidated. Almost 35% of this metal is produced by the five largest companies. These include:

• Codelco (Chile).
• Freeport-McMoRan (USA).
• Glencore (Switzerland).
• BHP Billiton (Australia).
• Southern Copper (Mexico).

These companies obtain almost 80% of copper from primary raw materials (that is, they carry out a full processing cycle) and produce 20% as a result of processing incoming scrap. In Europe, the largest copper producers are: Poland, Portugal and Bulgaria. Each plant is capable of producing a wide range of copper products.

Despite the current crisis, copper still remains a sought-after metal. One of the serious disadvantages inherent in this production is environmental problems. Assessments of emissions from copper smelters showed high levels of ambient air pollution.

It contains a large number of chemical compounds harmful to health (cadmium, mercury, arsenic, lead, nitrogen oxides and carbon).

Source: https://stankiexpert.ru/tehnologii/proizvodstvo-medi.html

Copper ore and pure copper mining technology

Copper, actively used in almost all industries, is mined from various ores, the most common of which is bornite. The popularity of this copper ore is explained not only by the high copper content in its composition, but also by significant reserves of bornite in the bowels of our planet.

Natural compounds containing copper

Pure copper, which is what its nuggets represent, is found in nature in very small quantities. Copper is mainly found in nature in the form of various compounds, the most common of which are the following.

• Bornite is a mineral that got its name in honor of the Czech scientist I. Born. This is a sulfide ore, the chemical composition of which is characterized by its formula - Cu5FeS4. Bornite has other names: variegated pyrite, copper purple. In nature, this ore is presented in two polymorphic forms: low-temperature tetragonal-scalenohedral (temperature less than 228 degrees) and high-temperature cubic-hexaoctahedral (more than 228 degrees). This mineral can have different types depending on its origin. Thus, exogenous bornite is a secondary early sulfide, which is very unstable and is easily destroyed by weathering. The second type, endogenous bornite, is characterized by variable chemical composition, which may contain chalcocite, galena, sphalerite, pyrite and chalcopyrite. Theoretically, minerals of these types can contain from 25.5% sulfur, more than 11.2% iron and over 63.3% copper, but in practice this content of these elements is never maintained.
• Chalcopyrite is a mineral whose chemical composition is characterized by the formula CuFeS2. Chalcopyrite, which is of hydrothermal origin, was previously called copper pyrite. Along with sphalerite and galena, it is included in the category of polymetallic ores. This mineral, which, in addition to copper, contains iron and sulfur, is formed as a result of metamorphic processes and can be present in two types of copper ores: contact-metasomatic type (skarns) and mountain metasomatic (greisens).
• Chalcocite is a sulfide ore, the chemical composition of which is characterized by the formula Cu2S. This ore contains a significant amount of copper (79.8%) and sulfur (20.2%). This ore is often referred to as “copper lustre”, due to the fact that its surface appears as a shiny metal, ranging in shades from lead-gray to completely black. In copper-bearing ores, chalcocite appears as dense or fine-grained inclusions.

In nature, there are also rarer minerals that contain copper.

• Cuprite (Cu2O), a member of the oxide group of minerals, can often be found in places where there is malachite and native copper.
• Covelline is a sulfide rock formed metasomatically. This mineral, whose copper content is 66.5%, was first discovered at the beginning of the last century in the vicinity of Vesuvius. Now covellite is actively mined in deposits in countries such as the USA, Serbia, Italy, and Chile.
• Malachite is a mineral well known to everyone as an ornamental stone. Surely everyone has seen products made from this beautiful mineral in the photo or even owns them. Malachite, which is very popular in Russia, is copper carbonate or copper dihydrocoxcarbonate, which belongs to the category of polymetallic copper-containing ores. The malachite found indicates that there are deposits of other minerals containing copper nearby. In our country, a large deposit of this mineral is located in the Nizhny Tagil region; previously it was mined in the Urals, but now its reserves there are significantly depleted and are not being developed.
• Azurite is a mineral that is also called “copper blue” due to its blue color. It is characterized by a hardness of 3.5–4 units; its main deposits are developed in Morocco, Namibia, Congo, England, Australia, France and Greece. Azurite is often intergrown with malachite and occurs in places where deposits of sulfide-type copper-bearing ores are located nearby.

Copper production technologies

To extract copper from the minerals and ores that we discussed above, modern industry uses three technologies: hydrometallurgical, pyrometallurgical and electrolysis.

The pyrometallurgical method of copper enrichment, which is the most common, uses chalcopyrite as a raw material. This technology involves performing several sequential operations.

At the first stage, copper ore is enriched, for which oxidative roasting or flotation is used.

The flotation method is based on the fact that the gangue and its parts containing copper are wetted differently.

When the entire mass of rock is placed in a bath with a liquid composition in which air bubbles are formed, the part that contains mineral elements is transported by these bubbles to the surface, adhering to them.

As a result, a concentrate is collected on the surface of the bath - blister copper, which contains from 10 to 35% of this metal. It is from this powdered concentrate that pure copper is further obtained.

Oxidative roasting, which is used to enrich copper ores containing a significant amount of sulfur, looks somewhat different.

This technology involves heating the ore to a temperature of 700–8000, as a result of which sulfides are oxidized and the sulfur content in copper ore is reduced by almost half.

After such roasting, the enriched ore is melted in reverberatory or shaft furnaces at a temperature of 14500, resulting in matte - an alloy consisting of copper and iron sulfides.

The properties of the resulting matte should be improved; for this, it is blown in horizontal converters without supplying additional fuel. As a result of such side blowing, iron and sulfides are oxidized, iron oxide is converted to slag, and sulfur is converted to SO2.

Blister copper, which is obtained as a result of this process, contains up to 91% of this metal. To make the metal even purer, it is necessary to refining the copper, for which it is necessary to remove foreign impurities from it. This is achieved using fire refining technology and an acidified solution of copper sulfate. This refining of copper is called electrolytic; it allows one to obtain metal with a purity of 99.9%.

There is also a hydrometallurgical method for copper enrichment, which involves leaching the metal using sulfuric acid. As a result of such leaching, a solution is obtained, from which copper and other metals, including precious ones, are then isolated. This technology is used for the beneficiation of ores, which are characterized by a very low copper content in their composition.

Source: http://met-all.org/cvetmet-splavy/med/mednye-rudy-dobycha-medi.html

How to mine copper at home - Metalist's Guide

Copper, classified as a non-ferrous metal, became known in ancient times. Man mastered its production earlier than iron. This is explained both by its frequent presence on the earth's surface in an accessible state, and by the relative ease of producing copper by extracting it from compounds. It got its name Cu from the island of Cyprus, where the ancient technology of copper production became widespread.

Due to its high electrical conductivity (copper is second only to silver among all metals), it is considered a particularly valuable electrical material. Although electrical wire, which previously accounted for up to 50% of global copper production, is now most often made from more affordable aluminum.

Copper, along with most other non-ferrous metals, is considered an increasingly scarce material. This is due to the fact that today those ores that contain about 5% copper are called rich, and its main production is carried out by processing 0.5% ores.

While in past centuries these ores contained from 6 to 9% Cu.

Copper is classified as a refractory metal. With a density of 8.98 g/cm3, its melting and boiling points are 1083°C and 2595°C, respectively. In compounds it is usually present with valency I or II; compounds with trivalent copper are less common. Salts of monovalent copper are slightly colored or completely colorless, and divalent copper gives its salts in an aqueous solution a characteristic color.

Pure copper is a malleable metal with a reddish or pink (at break) color. In the lumen of a thin layer, it may appear greenish or blue. Most copper compounds have these same colors. This metal is present in many minerals, of which only 17 are used in copper production in Russia.

The largest place in this is given to sulfides, native copper, sulfosalts and carbonates (silicates).

In addition to ores, the raw materials of copper production plants also include copper alloys from waste. Most often they include from 1 to 6% copper in sulfur compounds: chalcocite and chalcopyrite, coveline, bicarbonates and oxides, copper pyrites.

Also, ores, along with waste rock, including calcium carbonates, magnesium, silicates, pyrite and quartz, may contain components of such elements as gold, tin, nickel, zinc, silver, silicon, etc.

Not counting native ores, which include copper in an accessible form, all ores are divided into sulfide or oxidized, as well as mixed. The former are obtained as a result of oxidation reactions, and the latter are considered primary.

Production of black and refined copper

During the extraction of blister copper, the production provides for blowing the matte alloy in a side-blast converter with air. This is necessary to oxidize the iron combined with sulfur and convert it into slag. This procedure is called conversion and is divided into two stages.

The first is to produce white matte by oxidizing iron sulfide with quartz flux. The accumulated slag is removed, and in its place another portion of the original matte is placed, replenishing its constant volume in the converter. In this case, only white matte remains in the converter as the slag is removed. It contains predominantly copper sulfides.

The next part of the conversion process is the actual production of blister copper by remelting white matte. It is obtained by oxidation of copper sulfide. The rough copper obtained during blowing consists of 99% Cu with minor additions of sulfur and various metals. However, it is not yet suitable for technical use. Therefore, after conversion, the refining method is necessarily applied to it, i.e. purification from impurities.

  How to make a heat exchanger from a copper tube

In the production of refined copper of the required quality, rough copper is first exposed to fire, then to electrolytic action.

Through it, along with the elimination of unnecessary impurities, the valuable components contained in it are also obtained. To do this, blister copper at the fire stage is immersed in those furnaces that are used to smelt copper concentrate into matte alloy.

And for electrolysis, special baths are needed; their insides are covered with vinyl plastic or lead.

The purpose of the fire refining stage is the primary purification of copper from impurities, necessary to prepare it for the next refining stage - electrolytic. Oxygen, arsenic, antimony, iron and other metals are removed from copper melted by the fire method along with dissolved gases and sulfur.

Copper produced in this way may contain trace levels of selenium, tellurium and bismuth, which impairs its electrical conductivity and processability. These properties are especially valuable for the manufacture of copper products.

Therefore, electrolytic refining is used to obtain copper suitable for electrical engineering.

During electrolytic refining, an anode cast from copper that has undergone a fire refining stage and a cathode made from thin sheet copper are alternately immersed in a bath of sulfuric acid electrolyte through which a current is passed.

This operation allows high-quality purification of copper from harmful impurities with the simultaneous extraction of associated valuable metals from anode copper, which is an alloy of many components. The result of such refining is the production of cathode copper of high purity, containing up to 99.9% Cu, the production of sludge containing valuable metals, selenium with tellurium, as well as contaminated electrolyte.

Electrolytic refining is the main method of obtaining technically valuable copper for industry. In Russia, which is one of the leading countries in copper production, cable and wire products are made with its help.

Pure copper is widely used in electrical engineering. Copper alloys (brass, bronze, cupronickel, etc.) with zinc, iron, tin, manganese, nickel, and aluminum also occupy a large place here.

Copper salts are in demand in agriculture; they are used to produce fertilizers, synthesis catalysts, and pest control agents.

Source: https://ssk2121.com/kak-dobyt-med-v-domashnih-usloviyah/

Copper production

Copper or cuprum is named after the island of Cyprus, where a large deposit of it was found. This is one of the first metals mastered by man. The Copper Age is an amazing era in which human life was filled with copper tools and household items; it lasted from the 4th to the 3rd millennium BC. e.

Methods for obtaining copper

To extract copper from the minerals and ores in which it is found, three methods are currently used:

• hydrometallurgical
• pyrometallurgical
• electrolysis.

The production of copper by the pyrometallurgical method is the most common. The raw material for this process is chalcopyrite. To obtain pure copper from chalcopyrite, it is necessary to carry out a number of operations. The first of which is the beneficiation of copper ore using the method of oxidative roasting or flotation. Flotation is based on the fact that waste rock and its copper-containing parts are wetted differently.

If you place the entire mass of rock in a container with a liquid composition that contains air bubbles, then the part with mineral elements moves to the surface with the help of these bubbles and sticks to them. As a result, the presence of concentrate or blister copper is observed on the surface of the bath. This composition contains from 10 to 35% pure copper.

This powdered concentrate is the raw material for the further production of pure copper. The reactions for producing copper by oxidative roasting proceed in a completely different way. This method is used to enrich copper ores, which contain a significant amount of sulfur. To implement this technology, it is necessary to heat the ore to a temperature of 700–8000 degrees.

Under the influence of such high temperatures, sulfides are oxidized, and the volume of sulfur in copper ore is reduced by almost half. The next stage is the melting of enriched ore in reverberatory or shaft furnaces at a temperature of 14500. The result of this melt is the formation of matte - an alloy that consists of copper and iron sulfides.

To improve matte performance, it is subjected to blowing in horizontal converters without adding additional fuel. Thus, iron and sulfides are oxidized, iron oxide turns into slag, and sulfur becomes oxide - SO2.

Blister copper obtained in this way contains about 91% copper. To further purify the metal, copper is refined, that is, foreign impurities are removed. This is carried out thanks to the technology of fire refining in the presence of an acidified solution of copper sulfate.

This copper refining is electrolytic in nature, and makes it possible to obtain metal with a purity of 99.9%.

The hydrometallurgical method of copper enrichment is based on the process of leaching the metal using sulfuric acid. The result of this process is the production of a solution, from which pure copper is subsequently isolated. This method is also suitable for isolating precious metals.

This technology is used to enrich ores that contain extremely small amounts of copper.

Copper production by electrolysis

Electrolysis of copper is one of the stages of chemical-physical processes to which ore is subjected to obtain copper. It is noteworthy that to obtain 1 ton of pure copper, you will need to process at least 200 tons of copper ore. The procedure for processing copper ore itself is a multi-stage and very complex process, which consists of 7 stages. The latest is copper electrolysis.

After mining, the ore must be crushed in special machines. Next, the flotation process occurs, as a result of which, as we know, a concentrate is formed while preserving copper minerals. After this, firing occurs at high temperatures in special furnaces.

The charge obtained during the firing process is placed in a smelting furnace, where it becomes matte, which in turn is sent for conversion. The product obtained after these processes is called blister copper, where 2-3% of the volume is occupied by impurities. The impurities include zinc, iron, or sulfur. They are removed by an oxidation reaction.

At this stage, “red” copper is formed, which contains 99.7-99.9% Cu. The last stage is the electrolysis of copper itself, which allows us to obtain the purest copper possible.

To carry out the copper electrolysis process, you will need special equipment, namely containers that are filled with an aqueous solution of copper sulfate containing free sulfuric acid.

As a result of electrolysis, we will obtain a deposit of pure copper on the cathodes. And everything that ends up at the bottom of the bath is usually called sludge. It is a raw material for the production of precious metals.

Preparation of copper oxide

Copper (II) oxide CuO is a black crystal that undergoes crystallization in a monoclinic system. The density of the compound is 6.51 g/cm3, and it melts at a temperature of 1447 ° C under high pressure conditions. As a result of heating to 1100°C, copper (I) oxide is released:

Copper oxide does not dissolve in water and does not react with it.
It has weak amphoteric properties with a predominance of basic ones. Reacts with aqueous solutions of ammonia to form tetraammine copper (II) hydroxide:

• CuO + 4NH3 + H2O = [Cu(NH3)4](OH)2.

It also easily reacts with dilute acids, releasing salt and water:

• CuO + H2SO4 = CuSO4 + H2O.

The result of the fusion of copper oxide with alkalis is the formation of cuprates:

• CuO + 2KOH = K2CuO2 + H2O.

Pure copper oxide can be obtained by reduction with hydrogen, carbon monoxide and active metals:

• CuO + H2 = Cu + H2O
• CuO + CO = Cu + CO2
• CuO + Mg = Cu + MgO.

The reaction for producing copper oxide by calcination of copper (II) hydroxide at a temperature of 200°C:

Copper oxide can also be obtained through the oxidation of copper metal in air at a temperature of 400–500°C:

Preparation of copper sulfate

Copper sulfate can be obtained by three reactions:
dissolve CuO in H2SO4

in the presence of concentrated sulfuric acid with copper, always when heated

• Cu + 2H2SO4→ CuSO4 + SO2 + 2H2O

by the method of interaction of Cu2O with dilute sulfuric acid

• Cu2O + H2SO4 = Cu + CuSO4 + H2O.

Preparation of copper chloride

In nature, copper chloride is found in the very rare mineral ernochalcite CuCl₂•2H₂O, which is blue crystals.

Divalent copper chloride has important practical significance, and its extraction from natural minerals alone is very limited. Therefore, scientists have come up with several ways to artificially obtain this compound.

The main reaction of the industrial synthesis of CuCl₂ can be called the chlorination reaction of copper sulfide under high temperature conditions from 300 to 400 degrees °C. The reaction looks like this

Another option for the synthesis of cuprous chloride is chlorinating roasting, which is carried out at temperatures above 500 C:

• CuS + 2NaCl + 2O₂ ―› CuCl₂ + Na₂SO₄

Both reactions require the use of specialized equipment and increased safety precautions; for this reason, these reactions can only be carried out under industrial production conditions. In laboratory conditions, you can also obtain copper chloride by the following reactions

• Cu + Cl₂ ―› CuCl₂
• CuO + 2HCl ―› CuCl₂ +H₂O
• Cu(OH)₂ + 2HCl ―› CuCl₂ + 2H₂O. Neutralization reaction
• CuCO₃ + 2HCL ―› CuCl₂ + H₂O + CO₂. As a result of this reaction, the stronger acid will displace the acid residue of the weaker acid. A substitution reaction occurs
• 3Сu + 2HNO₃ + 6HCl ―› 3CuCl₂ + 2NO +4H₂0. This reaction is the most original. It occurs only in the presence of a mixture of two strong acids.

Preparation of copper glycerate

A qualitative reaction to detect the presence of glycerol in solutions is carried out in the presence of copper (II) sulfate and sodium hydroxide solution.
As a result of the reaction, copper glycerate is formed - a complex compound with a blue-cornflower blue hue. The chemical reaction is carried out as follows:

• a solution of sodium hydroxide is added to a solution of copper (II) sulfate, resulting in the solution turning blue. Thus, we observe the precipitation of copper (II) hydroxide
• after that, add a few ml of glycerin and mix the solution. The resulting precipitate dissolves to form an indigo-colored complex compound. This is copper glycerate.

The equation is as follows:
CH2OH-CHOH-CH2OH + Cu(OH)2—> Cu(-O-CH2-CH-O-)-CH2OH

Preparation of copper nitrate

Obtaining copper nitrate Cu(NO3)2 is quite an exciting activity. And also very useful, since it is a fairly popular dye. Copper(II) nitrate can be obtained by dissolving pure copper, its oxide or hydroxide in nitric acid. The equations look like this:

• Cu + 4HNO3 —> Cu(NO3)2 + 2NO2 + 2H2O
• CuO + 2HNO3 —> Cu(NO3)2 + H2O
• Cu(OH)2 + 2HNO3 —> Cu(NO3)2 +2H2O.

Preparation of copper sulfide

Copper(II) sulfide or copper monosulfide - CuS, is an inorganic binary compound of divalent copper with sulfur.
It is of the correct color, does not dissolve in water, and is also acidic in dilute solutions. In nature, it can be found in the form of the rare mineral covellite. Copper sulfide is obtained through direct interaction of elements, as well as as a result of the exchange reaction of divalent copper salts with water-soluble sulfides.

• Na2S+CuSO4=CuS+Na2SO4
• CuCl2 + H2S —> CuS + 2HCl
• 2CuS + H2 —>Cu2S + H2S. This reaction occurs under high temperature conditions of 600 to 700 oC

Preparation by the dry method gives copper sulfide the ability to conduct electric current. When the thermometer reaches 400 °C, noticeable decomposition of sulfide is observed.

Source: http://mining-prom.ru/cvetmet/med/poluchenie-medi/