Today, copper is a metal that is extremely popular and widely used both in everyday life and in industry. In nature, Cu can be found both in a pure state and in the form of ore. There are several ways to extract and obtain copper from the source rocks. Moreover, all of them are used in industry quite widely. How copper is mined will be discussed in the article.
A bit of history
In what area copper in ancient times began to be mined and used by man for the first time, archaeologists, unfortunately, could not find out. However, it is known for certain that it was this metal that people began to process and use in their daily lives the very first.
Copper became known to man back in the Stone Age. Some nuggets of this metal found by archaeologists carry traces of processing with stone axes. Initially, people used copper mainly as jewelry. At the same time, in ancient times, man used for the manufacture of such products exclusively the nuggets of this metal that he found. Later, people learned to process copper-containing ore.
The idea of how Cu is mined and how it is processed, had many peoples of antiquity. Archeologists have found many confirmations of this. After a person learned to make alloys of copper with zinc, the Bronze Age began. Actually the name "copper" was coined once by the ancient Romans. Such metal was brought to this country mainly from the island of Cyprus. Therefore, the Romans called it aes cyprium.
How copper was mined in antiquity
Since this metal was once widely used in human life, the technologies for its extraction were, of course, quite advanced. Our ancestors received copper mainly from malachite ores. A mixture of such material and coal was placed in a clay vessel and placed in a pit. Then the mass in the pot was set on fire. Carbon monoxide released as a result reduced malachite to copper.
Stocks in nature
Where can I get copper in the wild today? At the moment, deposits of this popular metal are discovered on all continents of the Earth. In this case, Cu reserves are considered almost unlimited. Today, geologists are finding ever new deposits of pure copper, as well as ore containing it. For example, in 1950 the world reserves of this metal amounted to 90 million tons. By 1970, this figure had already increased to 250 million tons, and by 1998 - up to 340 million tons. At present, it is believed that copper reserves on the planet are more than 2.3 billion tons.
Deposits and methods for the extraction of pure copper
As already mentioned, initially man used native Cu in everyday life. Of course, such pure copper is mined today. Nuggets of this metal are formed in the earth's crust as a result of exogenous and endogenous processes. The largest known native copper deposit on the planet is currently located in the United States, near Lake Superior. In Russia, native copper lies in the Udokan deposit, as well as in some other places in Transbaikalia. In addition, the Urals region also answers the question of where copper can be mined in Russia as nuggets.
In nature, a pure metal of this variety is formed in the oxidation zone of copper sulfate deposits. Typically, the nuggets of copper itself contain about 90-99%. The rest falls on other metals. In any case, the answer to the question of how native copper is mined are two main technologies. Deposits such as ore are being developed using a closed mine or open pit method. In the first case, such technological processes as drilling and breaking 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 find out where copper is mined in Russia. This is 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 860 kg nuggets is now stored in St. Petersburg, in the Museum of the Mining Institute.
Copper ores and their deposits
At present, obtaining Cu is considered economically viable and advisable even if it is contained in the rock at least 0.3%.
Most often, the following breeds are mined for industrial copper extraction in nature these days:
Bornites Cu 5 FeS 4 - sulfide ores, otherwise called copper purple or mottled pyrite and containing about 63.3% Cu;
chalcopyrites CuFeS 2 - minerals of hydrothermal origin;
chalcosines Cu 2 S containing more than 75% copper;
cuprites Cu 2 O, often found also in places of deposits of native copper;
malachites, which are carbon dioxide copper greens.
The largest copper ore deposit in Russia is located in Norilsk. Also, such rocks are produced in large quantities in some places in the Urals, Transbaikalia, Chukotka, Tuva and the Kola Peninsula.
How to develop copper ore deposits
Various kinds of rocks containing Cu, like nuggets, can be mined on the planet using two main technologies:
In the first case, mines are built at the field, the length of which can reach several kilometers. To move workers and equipment, such underground tunnels are equipped with elevators and railways. Rock crushing in mines is carried out using special drilling equipment with spikes. The collection of copper ore and its loading for shipment to the top are carried out using buckets.
If the deposits are located no further than 400-500 m from the surface of the earth, they are mined by the open method. In this case, the upper rock layer is first removed from the field using explosive devices. Further, the actual copper ore itself is gradually removed.
Methods for producing metal from rocks
Thus, we have found out how copper is mined, or rather, the ores containing it. But how then do the enterprises themselves obtain Cu itself?
There are three main ways to extract copper from rocks:
electrolytic;
pyrometallurgical;
hydrometallurgical.
Pyrometallurgical flotation method
This technology is usually used to extract copper from those rocks in which Cu contains 1.5-2%. Such material is subjected to flotation enrichment. Wherein:
ore is thoroughly ground to the smallest powder;
mix the resulting material with water;
special flotation reagents, which are complex organic substances, are added to the mass.
Flotoreagents cover small grains of various copper compounds and give them non-wettability.
In the next step:
As a result, light, dry particles of copper compounds adhere to air bubbles and float up. The foam containing them is collected, squeezed from water and dried thoroughly. As a result, a concentrate is obtained, from which blister Cu is then isolated.
How copper is mined from ore: beneficiation by roasting
The flotation method is used in industry quite often. But sometimes, roasting technology is also used to enrich copper ore. This technique is most often used for ores containing a large amount of sulfur. In this case, the material is preheated to a temperature of 700-8000 ° C. As a result, sulfides are oxidized with a decrease in sulfur content in the rock.
At the next stage, the ore thus prepared is melted in shaft furnaces at a temperature of 14500 ° C. Ultimately, using this technology, they get matte, an alloy of copper and iron. Further, this compound is improved by blowing in the converters. As a result, iron oxide passes into slag, and sulfur - into SO4.
Pure Copper Production: Electrolysis
Using flotation and firing methods, blister copper is obtained. Actually Cu such material contains about 91%. To obtain cleaner copper, the blister is subsequently refined.
In this case, thick anode plates are first cast from primary copper. Further:
a solution of copper sulfate is collected in the bath;
hanging 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 to the cathode, take away electrons from it and pass into Cu + 2 + 2e?> Cu atoms.
The impurities contained in blister copper can behave differently during cleaning. Zinc, cadmium, iron dissolve at the anode, but do not settle on the cathode. The fact is that in a series of electrochemical voltages they are located to the left of copper, that is, they have more negative potentials.
Copper sulfate is obtained by the slow oxidation of sulfide ore with oxygen to copper sulfate CuS + 2O 2 > CuSO 4 . 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, using this technology, a solution is saturated with Cu and other metals. Then copper is isolated from it. Using this technique, in addition to blister copper, other metals, including precious metals, can be obtained. In any case, this technology is used most often for the extraction of Cu from rocks not too rich in it (less than 0.5%).
Copper at home
The separation of this metal from the ores saturated with it is, therefore, technologically relatively uncomplicated. Some are therefore interested in how to get copper at home. To get this metal from ore, clay, etc. with your own hands, without the availability of special equipment, will, however, be very difficult.
Some, for example, are interested in how to get copper from clay with your own hands. Indeed, in nature there are deposits of this material, rich in including Cu. However, unfortunately, there are no known proven technologies for producing copper from clay at home.
With your own hands, you can try to isolate this metal at home, perhaps, only from copper sulfate. For this, the latter must first be dissolved in water. Further, in the resulting mixture, you just need to place some kind of iron object. After some time, the latter - as a result of the substitution reaction - will be covered with a copper coating, which in the future can simply be cleaned.