Anthracite (hard coal): characteristics and mining sites

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Anthracite is a kind of high quality fossil coal. It is characterized by a high level of metamorphism (degrees of solid phase and structural mineral alteration).

Like other types of fossils, anthracite - coal is formed over many millennia from plants that were without oxygen under the soil layers. For a considerable period of time they were subjected to the processes of coalification and humification. This was the formation of the specified substance. Carbon got its international name from the word carbon - coal. This is a true fact. Anthracite is the highest quality type of coal. It is also called carbuncle.

Characteristics of anthracite

In this case, there are several parameters. Namely availability:

• rich black or black-grey;
• high shine;
• high calorific value;
• significant electrical conductivity;
• high hardness and density.

Features of the formation of this fossil

Here several processes are taken into account. Anthracite is formed inin a certain order. First, peat is formed, and then brown-type coal. Further, under certain influences, this fossil passes into another substance. Namely, in coal and anthracite. In the latter case, this is a transitional link to graphite.

Anthracite (coal) occurs at a depth of about 6 km. Places where these fossils often self-form are characterized by peculiar shifts in the earth's crust. Basically, these are the spurs of the mountains.

The most numerous anthracite deposits are located in the coal basin in the Donetsk region.

Anthracite coal: product features

In this case, there are many specific nuances. Anthracite (from Greek anthrakitis) is a humic fossil coal. It has the highest degree of metamorphism. When observing it under a microscope, it is clear that plant remains are difficult to distinguish. Anthracite is a black charcoal, often with a grayish tint. It is sometimes found in its color and variegated tarnish. It gives a black-velvety line on a porcelain plate. Anthracite (coal) is also characterized by a strong metallic luster. It has high viscosity, does not sinter, and has good electrical conductivity. Its highest hardness on the mineralogical scale is 2.0-2.5, the organic mass density is 1500-1700 kg/m3. Its heat of combustion is 33.9-34.8 MJ/kg (8100-8350 kcal/kg). It has an analytical low humidity - 1-3% and contains up to 9% of volatile substances in the combustible mass, 93.5-97.0% carbon, 1-3% hydrogen, oxygen and nitrogen 1.5-2.0%. This is a definite fact. This fossil, which contains more than 97% carbon in the combustible mass, is called superanthracite. According to the volumetric yield of volatile substances, this product is divided into two industrial grades. Namely: with the presence of 220-330 l / kg - these are semi-anthracites, and with the presence of a volumetric yield of less than 220 l / kg - anthracites.

Benefits of said fossil

This product is the highest quality coal produced. It differs significantly from other types, as it has the following parameters:

• High amount of fixed carbon. In this case, it is 94-99%.
• Low Sulfur.
• High specific heating value.
• Low moisture.
• Burns without smoke or flame.
• Burn out quickly.
• High organic mass density. In this case, 1500-1700 kg per square meter.
• The specific gravity of anthracite coal is 1, 5-1, 7.
• High electrical conductivity.

In addition, anthracite coal, the photo of which is provided in this text, does not sinter during combustion. Its hardness according to the level of the mineralogical scale is 2.0-2.5. Another significant advantage is that only up to 5% of volatile substances are released in the air during the combustion of anthracite.

This type of fossil has calorific qualities superior to any other coal, namely: 8200 kilocalories per kilogram. By comparison, gas has a calorific value of 7000 kcal/kg.

What types are the givenfossil

Anthracite coal is a high-carbon product. This was discussed above. This and a number of other characteristics play a role in determining its scope. According to size classes, such a fossil as anthracite coal is classified (GOST 19242-73). The separation is carried out according to the size of the fractions of this product. Namely:

• "AKO" - anthracite fist, walnut. In this case, fractions with a size of 26-100 mm are taken into account.
• "AK" - anthracite coarse coal, fist. This includes fractions whose size is 50-100 mm.
• "AO" - anthracite walnut coal. The size of the fractions is 26-50 mm.
• "AM" is fine anthracite. In this case, fractions are taken into account - 13-25 mm.
• "AS" - coal brand anthracite seed. This includes fractions having a size of 6-13 mm.
• "Ashlam" - anthracite sludge. It is a kind of coal enrichment product.
• "ASh" - anthracite pebbles. In this case, the fractions are less than 6 mm.

Anthracite mining is carried out in the respective mines. They have a depth of up to 1500 m. Then the coal from the mines goes to the enterprises for its processing. There it is enriched and sorted into fractions. After that, coal in bags (anthracite) goes to various consumers.

This product is sold both in ordinary form (AR) and in enriched concentrated form. The specified fossil under the brands "AM" and "AKO" are identical in properties. Although the resistivity of coal is finetype has a higher.

Use of anthracites

This product is quite popular. Anthracite is the most dense type of coal. This allows him to take the first positions in the class of heat transfer and combustion time. If you buy anthracite (coal) for heating, then you will need it much less for heating the same area than if you use a similar product of a different type or firewood. Despite all the advantages of this fossil, it also has disadvantages. Possessing a significant density, it is not able to flare up in all types of boilers and furnaces. This is important to know. For good combustion of anthracite, you need a good air supply. Basically, in modern types of solid fuel boilers, it is forced. The less dense types of hard coal include: weakly caking and long-flame coal.

Anthracite, due to its calorific properties, is superior to other analogues. This parameter is 8200 kcal/kg. For example, natural gas - 7000 kcal / kg. Anthracite - coal, which is the hardest of all its analogues. During the combustion of volatile substances, only up to 5% is released from it. Anthracite is used in various fields of human activity. Namely: in industrial type production (chemistry, metallurgy, sugar industry, etc.), in the communal area (water heating, heating, and so on). It is also used for heating private households. Also, filtrants are produced from this fossil, which are used to treat wastewater,water and so on.

Anthracites in the power industry

In this area, the application of the specified product is also essential. Screenings from anthracites, which have a high ash content of class 0-13, are widely used as fuel in the electric power industry. In this industry, this fossil is used because of the low content of volatile substances. The electric power industry uses special equipment to burn anthracite.

Pulverized combustion of this product also requires specially designed fireboxes. Their configuration is quite peculiar. It must ensure the complete combustion of the specified fossil during the time when it is in a special combustion zone.

Coal with fine fractions, as well as a low content of sulfur, nitrogen and phosphorus, is used in special boilers that are designed for this. This small product is also used in cement kilns.

Anthracites in metallurgy

In this area, this fossil has also found its application. Anthracites in metallurgy are used for sintering iron and limestone. Blast-furnace and electric steel-smelting processes do not properly control the amount of harmful substances emitted into the atmosphere. Therefore, the use of the specified high-quality fuel by default allows you to make metallurgical processes more environmentally friendly.

In addition, this fine-type fossil is used in the production of high-carbon steels for secondary carburizing. In blast furnacesthose with PCI (pulverized fuel injection) systems can also use anthracite. Here the main indicator is the moisture content of the coal that is supplied.

In this case, the specified fuel can be blown into the blast furnace in bulk. This technology is very well used by the countries of Western Europe, as well as in Asia - China, Japan, Korea. In Russia and Ukraine, this method is only gaining popularity.

In the metallurgical industry, coal is also used as a metal reducing agent.

Anthracites - sorbents

This is another of the most promising directions in the use of this fossil. Anthracite can be used to purify drinking and waste water. In this case, it plays the role of a filter and can easily replace activated charcoal. This is a significant factor.

Alternative high-carbon feedstock

The coal market is traditionally divided into two segments. These include energy and coke production. Price trends for products depend on the segment and other factors. And often they are different.

Anthracite is a unique product successfully present in two segments. In addition, it still occupies a significant place in the specialized market for technological use. The price dynamics for a similar product in different segments may differ, that is, in this regard, there is a redistribution. For example, if the cost of one segment for anthracite falls, then for the other it, as a rule, grows.

Anthracites successfully compete with graphite,charcoal, petroleum coke. As a result, the amplitude of their prices will depend on the cost of electricity, metal products, and so on. This is important to remember. In addition, the price of anthracite will be influenced by the state of the world economy. However, over the past decade, the constant dynamics of its growth has been noticeable.

Conclusion

As a result of all of the above, we can say that hard coal is the most common type of mineral in the world. It has a high level of net quality energy output when generating electricity and high temperature heat for manufacturing processes. It is used in the chemical industry and is relatively inexpensive. With modern science and technology, it is impossible to completely replace anthracite in industry. This is a true fact. Consequently, in the near future there will be an intensive continuation of the extraction of anthracite and hard coal.