It is difficult to imagine something more indispensable for humanity than coal. Its use is so multifunctional that sometimes you are simply amazed. At such moments, doubt involuntarily creeps in, and a logical question sounds in my head: “What?” Is it all coal ?! ” Everyone is accustomed to consider coal as just a combustible material, but, in fact, its spectrum of application is so wide that it seems simply unbelievable.
Formation and origin of coal seams
The appearance of coal on Earth dates back to the distant Paleozoic era, when the planet was still in the development stage and had a completely alien appearance to us. The formation of coal seams began approximately 360,000,000 years ago. This happened mainly in the bottom sediments of prehistoric reservoirs, where organic materials have accumulated for millions of years.
Simply put, coal is the remains of the bodies of gigantic animals, tree trunks and other living organisms, sinking to the bottom, decaying and pressing under the water column. The formation of deposits is quite lengthy, and it takes at least 40,000,000 years to form a coal seam.
Coal mining
People very long ago realized how important and indispensable coal is, the properties and application of it were able to evaluate and adapt on such a scale relatively recently. Large-scale development of coal deposits began only in the XVI-XVII centuries. in England, and the extracted material was used mainly for smelting cast iron, necessary for the manufacture of guns. But its production by today's standards was so insignificant that it can not be called industrial.
Large-scale mining began only closer to the middle of the 19th century, when developing industrialization simply needed coal. Its use, however, at that time was limited exclusively to burning. Now hundreds of thousands of mines are operating all over the world, producing more per day than in several years in the 19th century.
Varieties of coal
Deposits of coal seams can reach depths of several kilometers extending into the earth, but not always and not everywhere, because it is heterogeneous both in content and in appearance.
There are 3 main types of this fossil: anthracite, brown coal, as well as peat, which very remotely resembles coal.
Anthracite is the oldest formation on the planet of this kind, the average age of this species is 280,000,000 years. It is very hard, has a high density, and its carbon content is 96-98%.
The hardness and density of brown coal is relatively low, as well as its carbon content. It has an unstable, loose structure and is also oversaturated with water, the content of which in it can reach up to 20%.
Peat is also referred to as a kind of coal, but not yet formed, so it has nothing to do with coal.
Coal properties
Now it is difficult to imagine other material more useful and practical than coal, the basic properties and application of which deserve the highest rating. Thanks to the substances and compounds contained in it, it has become simply indispensable in all areas of modern life.
The component of coal looks like this:
the average content of volatile substances reaches 35-40%;
the average ash content does not exceed 15-18%;
the average moisture content ranges from 12-15%;
the average calorie content is 5500-7000 kcal / kg.
All these components make coal, the application and use of which is so multifunctional. Volatile substances contained in coal provide rapid ignition followed by high temperatures. The moisture content simplifies the processing of coal, the caloric content makes its use indispensable in pharmaceuticals and cosmetology, ash itself is a valuable mineral material.
The use of coal in the modern world
The use of minerals is different. Coal was originally only a source of heat, then energy (turned water into steam), but now in this regard, the possibilities of coal are simply unlimited.
The thermal energy from the combustion of coal is converted into electrical energy, coke-chemical products are made from it and liquid fuel is extracted. Coal is the only rock in which such rare metals as germanium and gallium are contained in the form of impurities. Coke oven gas is extracted from it , which is then processed into benzene, from which the coumarone resin is used, which is used to make all kinds of paints, varnishes, linoleum and rubber. Aromatic hydrocarbons, phenols and pyridine bases are obtained from coal. During processing, coal is used in the production of vanadium, graphite, sulfur, molybdenum, zinc, lead and many more valuable and irreplaceable products now.