Minerals: Coal. See what "Coal" is in other dictionaries

Almost 200 years ago, the brilliant Russian scientist M. V. Lomonosov quite correctly explained the formation of fossil coal from plant residues, just as peat is now formed. Lomonosov also indicated the conditions necessary for the transformation of peat into coal: the decomposition of vegetation "without free air", the high temperature inside the Earth and the "burden of the roof", that is, the pressure of rocks.

It takes a very long time for peat to turn into coal. Peat accumulates in the swamp, and from above the swamp is overgrown with more and more new layers of plants. At depth, peat is constantly changing. The complex chemical compounds that make up plants break down into simpler ones. One part dissolves and is carried away with water, the other passes into a gaseous state: carbon dioxide and light gas - methane (the same gas burns in our stoves). An important role in the formation of coal is played by fungi and bacteria that inhabit all peat bogs. They help the destruction of plant tissue. In the process of these changes in peat, the most stable substance, carbon, accumulates in it. As it changes, peat becomes more and more rich in carbon.

The accumulation of carbon in peat occurs without access to oxygen, otherwise carbon, combining with oxygen, would turn completely into carbon dioxide and evaporate. The resulting layers of peat are first isolated from the oxygen of the air by the water covering them, then by newly emerging layers of peat.

This is how the process of turning peat into fossil coal gradually proceeds. There are several main types of fossil coal: lignite, brown coal, bituminous coal, anthracite, boghead, etc.

The most similar to peat is lignite - loose brown coal, of not very old origin. It clearly shows the remains of plants, mainly wood (hence the name "lignite", which means "wooden"). Lignite is woody peat. In modern peat bogs of the temperate zone, peat is formed mainly from peat moss, sedge, reeds, but in the subtropical zone the globe, for example, in the forest swamps of Florida in the USA, woody peat is also formed, very similar to fossil lignite.

With a stronger decomposition and change in plant residues, brown coal is created. Its color is dark brown or black; it is stronger than lignite, wood remains are less common in it and it is more difficult to see them. When burning brown coal gives off more heat than lignite, since it is richer in carbon. Brown coal does not always turn into hard coal over time. It is known that the brown coal of the Moscow Basin is of the same age as the hard coal on the western slope of the Urals (Kizel basin). The process of turning brown coal into hard coal occurs only when layers of brown coal sink into deeper horizons of the earth's crust or mountain building processes occur. For the transformation of brown coal into - stone or anthracite, a very high temperature and great pressure in the bowels of the Earth are needed. In coal, only under a microscope are the remains of plants visible; it is heavy, lustrous, and often very strong. Some grades of coal themselves or together with other grades coke, that is, they turn into coke.

The largest amount of carbon contains black shiny coal - anthracite. You can find the remains of plants in it only under a microscope. When burned, anthracite gives off more heat than all other grades of coal.

Boghead - dense black coal with a conchoidal fracture surface; during dry distillation, it gives a large amount of coal tar - a valuable raw material for chemical industry. Boghead is formed from algae and sapropel.

The longer the coal lies in the earth's layers and the more it is subjected to pressure and the action of deep heat, the more carbon it contains. Anthracite contains about 95% carbon, brown coal - about 70%, and peat - from 50 to 65%.

In the swamp, where peat initially accumulates, clay, sand and various dissolved substances usually get along with water. They form mineral impurities in peat, which then remain in coal. These impurities often form interlayers that separate the coal seam into several layers. The admixture contaminates the coal and makes it difficult to develop.

When coal is burned, all mineral impurities remain in the form of ash. The better the coal, the less ash it should contain. AT good varieties coal is only a few percent, but sometimes the amount of ash reaches 30-40%. If the ash is more than 60%, then coal does not burn at all and is not suitable for fuel.

To obtain fuel with a low content of foreign impurities from coal, coal is enriched. From the mine, the rock is immediately sent to the processing plant. There, the rock mined in the mine is crushed into small pieces in special machines, and then all clay lumps are separated from the coal. Clay is always heavier than coal, so the mixture of coal and clay is washed with a stream of water. The strength of the jet is chosen so that it takes out coal, and heavier clay would remain below. Then water with coal is passed through a frequent grate. The water drains and the coal, now clean and free of clay particles, collects on the surface of the grate. Such coal is called enriched. There will be very little ash left in it. It happens that the ash in coal is not a harmful impurity, but a mineral. Thus, for example, thin, clayey turbidity, brought into the swamp by streams and rivers, often forms interlayers of valuable refractory clay. It is specially developed or collected from the ash remaining after the combustion of coal, and then used to make porcelain dishes and other products. Sometimes found in the ashes of coal.

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It takes a long time for the peat to turn into coal. Peat gradually accumulates in the swamp. The swamp, in turn, is overgrown with ever larger layers of plants. At depth, the peat changes all the time. Complex chemical compounds that are found in plants break down into simpler ones. Partially they dissolve and are carried away with water, partially they pass into a gaseous state: carbon dioxide and methane. An important role in the formation of coal is played by bacteria and all kinds of fungi that inhabit everything. They contribute to the decomposition of plant tissue. In the process of such changes in peat, the most stable substance, carbon, begins to accumulate in it over time. Over time, peat carbon in peat becomes more and more.

The accumulation of carbon in peat occurs without access to oxygen, otherwise carbon, combining with oxygen, would turn completely into carbon dioxide and evaporate. The forming layers of peat are first isolated from the oxygen of the air by the water covering them, then by the newly emerging layers of peat.

So gradually the process of turning peat into. There are several main types of fossil coal: lignite, brown coal, bituminous coal, anthracite, boghead, etc.

Most similar to peat lignite- loose brown coal, of not very old origin. It clearly shows the remains of plants, mainly wood (hence the name "lignite", which means "wooden"). Lignite is woody peat. In modern temperate peat bogs, peat is formed mainly from peat moss, sedge, reeds, but in the subtropical zone of the globe, for example, in Florida forest bogs in the USA, woody peat is also formed, very similar to fossil lignite.

With a stronger decomposition and change in plant residues, brown coal. Its color is dark brown or black; it is stronger than lignite, wood remains are less common in it, and it is more difficult to see them. When burning brown coal gives off more heat than lignite, since it is richer in carbon. Brown coal does not always turn into hard coal over time. It is known that the brown coal of the Moscow Basin is of the same age as the hard coal on the western slope of the Urals (Kizel basin). The process of turning brown coal into hard coal occurs only when layers of brown coal sink into deeper horizons of the earth's crust or mountain building processes occur. For the transformation of brown coal into stone or anthracite, a very high temperature and high pressure in the bowels of the Earth are needed. AT coal only under a microscope are the remains of plants visible; it is heavy, lustrous, and often very strong. Some grades of coal themselves or together with other grades coke, that is, they turn into coke.

The largest amount of carbon contains black shiny coal - anthracite. You can find the remains of plants in it only under a microscope. When burned, anthracite gives off more heat than all other grades of coal.

Boghead- dense black coal with a conchoidal fracture surface; dry distillation gives a large amount of coal tar - a valuable raw material for the chemical industry. Boghead is formed from algae and sapropel.

The longer the coal lies in the earth's layers, or the more it is subjected to pressure and the action of deep heat, the more carbon it contains. Anthracite contains about 95% carbon, brown coal - about 70%, and peat - from 50 to 65%. In the swamp, where peat initially accumulates, clay, sand and various dissolved substances usually get along with water. They form mineral impurities in peat, which then remain in coal. These impurities often form interlayers that separate the coal seam into several layers. The admixture contaminates the coal and makes it difficult to develop.

When coal is burned, all mineral impurities remain in the form of ash. The better the coal, the less ash it should contain. In good grades of coal, it is only a few percent, but sometimes the amount of ash reaches 30-40%. If the ash is more than 60%, then coal does not burn at all and is not suitable for fuel.

Coal seams are different not only in their composition, but also in structure. Sometimes the entire seam is composed of pure coal throughout its entire thickness. This means that it was formed in a peat bog, where water polluted with clay and sand almost did not get. Such coal can be burned immediately. More often, coal seams alternate with clayey or sandy interlayers. Such seams of coal are called complex. In them, for example, a seam of 1 m thick often has 10-15 layers of clay, several centimeters thick each, and pure coal accounts for only 60-70 cm; while the coal can be of very good quality. To obtain fuel with a low content of foreign impurities from coal, coal is enriched. From the mine, the rock is immediately sent to the processing plant. There, the rock mined in the mine is crushed into small pieces in special machines, and then all clay lumps are separated from the coal. Clay is always heavier than coal, so the mixture of coal and clay is washed with a stream of water. The strength of the jet is chosen so that it takes out coal, and heavier clay would remain below. Then water with coal is passed through a frequent grate. The water drains and the coal, now clean and free of clay particles, collects on the surface of the grate. Such coal is called enriched. There will be very little ash left in it. It happens that the ash in coal is not a harmful impurity, but a mineral. Thus, for example, thin, clayey turbidity, brought into the swamp by streams and rivers, often forms interlayers of valuable refractory clay. It is specially developed or collected from the ash remaining after the combustion of coal, and then used to make porcelain dishes and other products. Sometimes found in the ashes of coal

It is generally accepted that the main deposits of fossil coal were formed mainly in a separate period of time, when the most favorable conditions for this were formed on Earth. Due to the connection of this period with coal, it received its name of the Carboniferous period, or Carboniferous (from the English “carbon” - “coal”).

The beginning of the Carboniferous, according to scientists, is marked by a significant change in conditions on the surface of the planet - the climate has become significantly more humid and warmer than in the previous period.

In countless lagoons, river deltas and swamps, a lush warm and moisture-loving flora reigned. Colossal amounts of peat-like plant matter accumulated in places of its mass development, and, over time, under the influence of chemical processes, they were transformed into vast deposits of coal.

Coal seams often contain (according to geologists and paleobotanists) "beautifully preserved remains of plants, indicating that" during the Carboniferous period, many new species of flora appeared on Earth. It was literally a time of riot of greenery.

Rice. 202.Sunrise in the carbon forest

The process of coal formation is most often described as follows:

“This system is called coal because among its layers there are the most powerful interlayers of coal, which are known on Earth. Seams of coal originated due to the charring of plant remains, buried in masses in sediments. In some cases, accumulations of algae served as the material for the formation of coals, in others - accumulations of spores or other small parts of plants, in others - trunks, branches and leaves of large plants.

Over time, in such organic remains, it is believed that plant tissues slowly lose some of their constituent compounds released into gaseous state, some, and especially carbon, are pressed by the weight of the precipitation that has fallen on them and turn into coal. First, peat turns into brown coal, then into hard coal, and finally into anthracite. All this happens at high temperatures.

“Anthracites are coals that have been altered by the action of heat. Pieces of anthracite are filled with a mass of small pores formed by bubbles of gas released during the action of heat due to the hydrogen and oxygen contained in the coal. It is believed that the source of the heat could be the proximity to the eruptions of basalt lavas along the cracks in the earth's crust.

It is believed that under the pressure of sediment layers 1 km thick, a layer of brown coal 4 meters thick is obtained from a 20-meter layer of peat. If the depth of burial of plant material reaches 3 kilometers, then the same layer of peat will turn into a layer of coal 2 meters thick. At a greater depth, about 6 kilometers, and at a higher temperature, a 20-meter layer of peat becomes a layer of anthracite 1.5 meters thick.

In conclusion, we note that in a number of sources, the chain "peat - lignite - coal - anthracite" is supplemented with graphite and even diamond, resulting in a chain of transformations: "peat - lignite - coal - anthracite - graphite - diamond" ...

A huge amount of coal, which for more than a century has been feeding world industry, according to the "generally accepted" opinion, indicates the vast extent of the marshy forests of the Carboniferous era.

Rice. 203.Coal mining in an open cut

The above so-called biogenic (organic) version of the origin of coal is actively opposed by creationists, who are not satisfied with the age of coal seams of hundreds of millions of years, since it contradicts the texts Old Testament. They carefully collect arguments pointing to the contradictions between this theory and the actual nature of the occurrence of coal seams. And if we ignore the commitment to the creationist version of too short story of our planet (no more than ten thousand years in total, as follows from the Old Testament), it should be recognized that whole line their arguments are quite serious. For example, they noticed such a rather common strange feature of coal deposits as the non-parallelism of its different layers.

“In extremely rare cases, coal seams lie parallel to each other. Nearly all hard coal deposits at some point split into two or more separate seams. The combination of an already almost fractured layer with another, located above, from time to time appears in the deposits in the form of Z-shaped joints. It is difficult to imagine how two superimposed strata should have arisen from the deposition of growing and replacing forests if they are connected to each other by crowded groups of folds or even Z-shaped joints. The connecting diagonal layer of the Z-shaped connection is particularly striking evidence that both layers that it connects were originally formed simultaneously and were one layer, but now they are two horizontal lines of petrified vegetation located parallel to each other ”(R. Juncker, Z .Scherer, "History of the origin and development of life").

Such folds and Z-shaped connections fundamentally contradict the "generally accepted" scenario of the origin of coal. And within this scenario, the folds and Z-joints are completely unexplained. But we are talking about empirical data found everywhere!..

Rice. 204.Z-junctions of coal seams in the Oberhausen-Duisburg area

For more details on the arguments against the biogenic version of the formation of coal, see my book "The Sensational History of the Earth", which was already mentioned earlier. Here we will give only one more fact, which the creationists did not pay attention to, but which is simply "killer" for the "generally accepted" theory.

Let's look at brown and hard coal from the standpoint of chemical composition.

When coal is mined, the content of mineral impurities in it, or the so-called "ash content", which varies widely - from 10 to 60%, is of great importance. Thus, the ash content of the coals of the Donetsk, Kuznetsk and Kansk-Achinsk basins is 10-15%, Karaganda - 15-30%, Ekibastuz - 30-60%.

And what is “ash content”?.. And what are these very “mineral impurities”?..

In addition to clay inclusions, the appearance of which in the process of accumulation of the initial peat (if we stick to the version of coal formation from peat) is quite natural, among the impurities most often mentioned ... sulfur!

“In the process of peat formation, coal gets different elements, most of which is concentrated in ash. When coal is burned, sulfur and some volatile elements are released into the atmosphere. The relative content of sulfur and ash-forming substances in coal determines the grade of coal. In high grade coal less sulfur and less ash than low-grade, so it is in greater demand and more expensive.

Although the sulfur content of coals can vary from 1 to 10%, most coals used in industry have a sulfur content of 1-5%. However, sulfur impurities are undesirable even in small quantities. When coal is burned, most of the sulfur is released into the atmosphere as harmful pollutants called sulfur oxides. In addition, the admixture of sulfur has a negative impact on the quality of coke and steel smelted on the basis of the use of such coke. Combining with oxygen and water, sulfur forms sulfuric acid, which corrodes the mechanisms of coal-fired thermal power plants. Sulfuric acid is present in mine waters seeping from waste workings, in mine and overburden dumps, polluting environment and hindering the development of vegetation.

And here a very serious question arises - where did sulfur come from in coal ?!. More precisely: where did she come from in such a in large numbers?!. Up to ten percent!

Rice. 205.On a peat bog

I'm ready to bet - even with my far from complete education in the field of organic chemistry - such amounts of sulfur have never been in wood and could not be! .. Neither in wood nor in other vegetation that could become the basis of peat, in the future transformed into coal! .. There is less sulfur by several orders of magnitude! ..

Furthermore. If you type in a search engine a combination of the words "sulphur" and "wood", then most often only two options are displayed, both of which are associated with the "artificial and applied" use of sulfur - for wood conservation and for pest control. In the first case, the property of sulfur to crystallize is used - it clogs the pores of the tree and is not removed from them at ordinary temperatures. In the second, the application is based on the toxic properties of sulfur, even in small quantities.

If there was so much sulfur in the original peat, then how could the trees that formed it grow at all?.. Or, for some unknown reason, some “ancient sulfur”, contrary to its modern behavior, did not clog the pores of ancient plants?..

And how, instead of dying out, on the contrary, all those insects that bred in incredible quantities in the Carboniferous period and at a later time and fed on plant sap, which contained so much poisonous sulfur, felt more than comfortable? .. However, even now it is swampy the terrain creates very comfortable conditions for insects ...

But sulfur in coal is not just a lot, but a lot! .. Since we are talking about even sulfuric acid in general! ..

Moreover, coal is often accompanied by deposits of such a useful sulfur compound in the economy as sulfur pyrite. Moreover, the deposits are so large that its extraction is organized on an industrial scale! ..

“... in the Donets Basin, the extraction of coal and anthracite of the Carboniferous period also goes hand in hand with the development of iron ores mined here ... Sulfur pyrite is an almost constant companion of coal and, moreover, sometimes in such quantity that it makes it unfit for consumption (for example, coal of the Moscow basin). Sulfuric pyrite is used to produce sulfuric acid, and from it, by metamorphization, ... iron ores originated.

This is no longer a mystery. This is a direct and immediate contradiction between the theory of coal formation from peat and real empirical data!!!

Coal, like oil and gas, is organic matter that has been slowly decomposed by biological and geological processes. The basis of coal formation is plant residues. Depending on the degree of transformation and the specific amount of carbon in coal, four types of it are distinguished: brown coals (lignites), hard coals, anthracites and graphites. AT Western countries there is a slightly different classification - lignites, sub-bituminous coals, bituminous coals, anthracites and graphites, respectively.

Anthracite

Anthracite- the most deeply warmed up at its origin from fossil coals, coal of the highest degree of coalification. It is characterized by high density and gloss. Contains 95% carbon. It is used as a solid high-calorie fuel (calorific value 6800-8350 kcal/kg). They have the highest calorific value, but ignite poorly. They are formed from coal with an increase in pressure and temperature at depths of about 6 kilometers.

Coal

Coal- sedimentary rock, which is a product of deep decomposition of plant remains (tree ferns, horsetails and club mosses, as well as the first gymnosperms). By chemical composition coal is a mixture of high molecular weight polycyclic aromatic compounds with a high mass fraction of carbon, as well as water and volatile substances with small amounts of mineral impurities, which form ash when coal is burned. Fossil coals differ from each other in the ratio of their components, which determines their heat of combustion. A number of organic compounds that make up coal have carcinogenic properties.

Brown coal- solid fossil coal, formed from peat, contains 65-70% carbon, has a brown color, the youngest of fossil coals. It is used as a local fuel, as well as a chemical raw material. They contain a lot of water (43%) and therefore have a low calorific value. In addition, they contain a large number of volatile substances (up to 50%). They are formed from dead organic residues under the pressure of the load and under the influence of elevated temperature at depths of the order of 1 kilometer.

Coal mining

Coal mining methods depend on the depth of its occurrence. The development is carried out by an open method in coal mines, if the depth of the coal seam does not exceed 100 meters. There are also frequent cases when, with an ever-increasing deepening of a coal pit, it is further advantageous to develop a coal deposit by an underground method. Mines are used to extract coal from great depths. The deepest mines in the Russian Federation extract coal from a level of just over 1200 meters.

Along with coal, coal-bearing deposits contain many types of georesources that have consumer significance. These include host rocks as a raw material for the construction industry, groundwater, coal-bed methane, rare and trace elements, including valuable metals and their compounds. For example, some coals are enriched with germanium.

This article provides information on one interesting sedimentary rock, which is a source of great economic importance. This breed, amazing in its history, is called "coal". His education is quite interesting. It should be noted that, despite the fact that this rock makes up less than one percent of all sedimentary rocks existing on earth, it has great importance in many areas of people's lives.

general information

How was coal formed? Its formation includes many processes occurring in nature.

Coal appeared on Earth about 350 million years ago. To put it simply, it happened in the following way. Tree trunks, falling into the water with other vegetation, gradually formed huge layers of organic undecomposed mass. Limited access oxygen did not allow this mess to decompose and rot, which gradually, under its own weight, sank deeper and deeper. For a long time and due to the displacement of the layers of the earth's crust, these layers went to a considerable depth, where, under the influence of elevated temperatures and high pressure, this mass was converted into coal.

Below we will take a closer look at how coal appeared, the formation of which is very interesting and curious.

Types of coal

Modern coal deposits in the world produce different types hard coal:

1. Anthracites. These are the hardest varieties, mined from great depths and having the highest combustion temperature.

2. Coal. Many of its varieties are mined in an open way and in mines. This type the most widespread in the spheres of human activity.

3. Brown coal. This is the youngest species formed from peat residues and has the lowest combustion temperature.

All of the listed forms of coal occur in layers, and the places of their accumulation are called coal basins.

Theories of the origin of coal

What is hard coal? Simply put, this sedimentary rock is the accumulated, compacted and processed plants over time.

There are two theories, the more popular of which is the one held by many geologists. It is as follows: the plants that make up coal accumulated in large peat or freshwater swamps for many thousands of years. This theory assumes the growth of vegetation in the place of discovery of rocks and is called "autochthonous".

Another theory is based on the fact that coal seams accumulated from plants transferred from other places, which were deposited in a new site under flooding conditions. In other words, the charcoal originated from the transferred plant debris. The second theory is called allochthonous.

In both cases, the source of coal formation is plants.

Why is this stone on fire?

Basic chemical element in a corner with useful properties, - carbon.

Depending on the formation conditions, processes and age of the seams, each coal deposit contains its own specific percentage of carbon. This indicator determines the quality of natural fuel, since the level of heat transfer is directly related to the amount of carbon oxidized during combustion. The higher the calorific value of a given rock, the more suitable it is as a source of heat and energy.

What is coal for people all over the world? First of all, it is the best fuel suitable for different areas vital activity.

About fossils in coal

Fossil plant species found in coal do not support the autochthonous theory of origin. Why? For example, clubmosses and giant ferns, characteristic of the coal deposits of Pennsylvania, could grow in marshy conditions, while other fossil plants of the same basin ( conifer tree or giant horsetail, etc.) preferred drier soils rather than marshy places. It turns out that they were transferred somehow to these places.

How did coal originate? Education in nature is amazing. Marine fossils are often found in the coal: mollusks, fish and brachiopods (or brachiopods). Coal seams also contain coal balls (rounded crumpled masses of perfectly preserved fossil plants and animals, including marine ones). For example, the small sea worm is usually found attached to plants in coals. North America and Europe. They belong to the Carboniferous period.

The occurrence of marine animals interspersed with non-marine plants in coal-sedimentary rocks suggests that they mixed in the process of moving. Amazing and lengthy processes took place in nature before coal was finally formed. Its formation in this way confirms the allochthonous theory.

Amazing finds

The most interesting finds in the layers of coal are tree trunks, lying vertically. They often cross huge strata of rocks perpendicular to the coal bed. Trees in this vertical position are often found in seams associated with coal deposits, and a little less often in the coal itself. Many are of the opinion about the movement of tree trunks.

The amazing thing is that sediment had to accumulate so quickly to cover these trees before they deteriorated (rotted) and fell.

This is pretty interesting story formation of a rock called coal. The formation of such layers in the bowels of the earth is a reason for further research in search of answers to numerous questions.

Where are the lumps in the coal?

Impressive external feature coal is the content in it of huge blocks. These large blocks have been found in the coal seams of many deposits for more than a hundred years. Average weight 40 lumps collected from the West Virginia coalfield was about 12 pounds, and the largest was 161 pounds. Moreover, many of them were metamorphic or volcanic rock.

Researcher Price suggested that they could have traveled to the coalfield in Virginia from afar, weaving into the roots of trees. And this conclusion also supports the allochthonous model of coal formation.

Conclusion

Many studies prove the truth of the allochthonous theory of the formation of coal: the presence of the remains of terrestrial and marine animals and plants implies their movement.

Also, studies have shown that the metamorphism of this rock does not require a long time (millions of years) of exposure to pressure and heat - it can also be formed as a result of rapid heating. And the trees vertically located in the coal sediments confirm the fairly rapid accumulation of vegetation residues.