Coal: properties. Hard coal: origin, production, price

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

Since ancient times, mankind has been using coal as one of the sources of energy. And today this mineral is used quite widely. Sometimes it is called solar energy, which is preserved in stone.

Application

Coal is burned to produce heat that is used for hot water and home heating. The mineral is used in the technological processes of metal smelting. Thermal power plants convert coal into electricity by burning it.

Scientific advances have made it possible to use this valuable substance in other ways. Thus, the chemical industry has successfully mastered a technology that makes it possible to obtain liquid fuel from coal, as well as such rare metals as germanium and gallium. Carbon-graphite composite materials with a high carbon concentration are currently being extracted from a valuable fossil. Methods have also been developed to produce plastics and high-calorie gaseous fuels from coal.

Very low fraction of low-grade coal and its dust are pressed into briquettes after processing. This material is great for heating private houses and industrial premises. Generallyproduce more than four hundred items of various products after chemical processing, which is subjected to coal. The price of all these products is dozens of times higher than the cost of raw materials.

Over the past few centuries, mankind has been actively using coal as a fuel necessary for obtaining and converting energy. Moreover, the need for this valuable mineral has been increasing in recent years. This is facilitated by the development of the chemical industry, as well as the need for valuable and rare elements obtained from it. In this regard, intensive exploration of new deposits is currently underway in Russia, mines and quarries are being created, enterprises are being built to process this valuable raw material.

Origin of the fossil

In ancient times, the Earth had a warm and humid climate, in which diverse vegetation flourished. From it coal was later formed. The origin of this fossil lies in the accumulation of billions of tons of dead vegetation at the bottom of the swamps, where they were covered with sediment. About 300 million years have passed since then. Under the powerful pressure of sand, water and various rocks, vegetation slowly decomposed in an oxygen-free environment. Under the influence of high temperatures, which were given by the closely located magma, this mass solidified, which gradually turned into coal. The origin of all existing deposits has only such an explanation.

Reserves of minerals and its production

There are large deposits on our planetcoal. In total, according to experts, the earth's bowels store fifteen trillion tons of this mineral. Moreover, the extraction of coal in terms of its volume is in the first place. It is 2.6 billion tons per year, or 0.7 tons per inhabitant of our planet.

Coal deposits in Russia are located in different regions. Moreover, in each of them, the mineral has different characteristics and has its own depth of occurrence. Below is a list that includes the largest hard coal deposits in Russia:

1. Elga deposit. It is located in the southeastern part of Yakutia. The depth of coal in these places allows for open-pit mining. This does not require special costs, which affects the reduction in the cost of the final product.
2. Tuva field. According to experts, there are about 20 billion tons of minerals on its territory. The field is very attractive for development. The fact is that eighty percent of its deposits are located in one layer, which has a thickness of 6-7 meters.
3. Minusinsk deposits. They are located in the Republic of Khakassia. These are several deposits, the largest of which are Chernogorskoye and Izykhskoye. Pool stocks are small. According to experts, they range from 2 to 7 billion tons. Coal, which is very valuable in terms of its characteristics, is mined here. The properties of the mineral are such that when it is burned, a very hightemperature.
4. Kuznetsk coal basin. This deposit, located in the west of Siberia, provides a product used in ferrous metallurgy. The coal that is mined in these places goes for coking. The volume of deposits here is simply huge.
5. Kuznetsk Alatau. This deposit gives a product of the highest quality. The greatest depth of mineral deposits reaches five hundred meters. Mining is carried out both in open cuts and in mines.

Coal in Russia is mined in the Pechora coal basin. Deposits are also being actively developed in the Rostov region.

Choice of coal for the production process

In different industries there is a need for different grades of minerals. What are the differences between hard coal? The properties and quality characteristics of this product vary widely.

This happens even if the coal has the same label. The fact is that the characteristics of a fossil depend on the place of its extraction. That is why each enterprise, choosing coal for its production, should familiarize itself with its physical characteristics.

Properties

Coal differs in the following properties:

1. Density. This is one of the most important characteristics, which ranges from 1.28 to 1.53 grams per cubic centimeter. With increasing density values, the specific heat of combustion of hard coal increases.



2. Carbon content. This figure ranges from 75 to 97 percent. With a higher carbon content in the fuel, there is less volume for foreign impurities. This allows you to get the maximum amount of energy when burning the product.
3. Mechanical strength. This characteristic determines the ability of the fossil to endure transportation. This parameter ranges from 40 kilograms per square centimeter (for brown coals) to 300 (for anthracites).
4. Sulfur content. In the corner it can be from 0.5 to 5.4 percent. With a smaller value of this value, it is safer to use fuel.
5. Volatile components yield (2-45%).
6. Humidity. Fuel can contain from 4 to 15 percent moisture. From this indicator directly depends on whether coal is effective when burned. The properties of a wetter product are fundamentally different from a dry one. Such coal crumbles and undergoes rapid weathering.
7. Ash content. This characteristic indicates the amount of non-combustible mixtures contained in the fossil. With a lower ash content, the specific heat capacity increases. Anthracites have the lowest percentage of non-combustible mixtures. It is within 2%. Ash content within thirty percent is acceptable for heating. The highest value of this characteristic is 45%.
8. Specific calorific value. This indicator is in the range from 6500 to 8600 kcal / kg. It characterizes the amount of heat that is generated during the combustion of one kilogram of fuel.

Degree of enrichment

Depending on purposeuse can be purchased various coal coal. In this case, the properties of the fuel become clear, based on the degree of its enrichment. Highlight:

1. concentrates. Such fuel is used in the production of electricity and heat.

2. industrial products. They are used in metallurgy.

3. Sludge. This is a fine fraction of coal (up to six millimeters), as well as dust resulting from rock crushing. The sludge is used to form briquettes, which have good performance properties for domestic solid fuel boilers.

Degree of coalification

According to this indicator, they distinguish:

1. Brown coal. This is the same coal, only partially formed. Its properties are somewhat worse than those of higher quality fuel. Brown coal produces low heat during combustion and crumbles during transportation. In addition, it has a tendency to spontaneous combustion.

2. Coal. This type of fuel has a large number of grades (brands), the properties of which are different. It is widely used in energy and metallurgy, housing and communal services and the chemical industry.

3. Anthracites. This is the highest quality type of hard coal.

The properties of all these forms of minerals are significantly different from each other. So, brown coal is characterized by the lowest calorific value, and anthracites are the highest. What is the best coal to buy? The price must be economically feasible. Based on this, the cost and specific heat are in the optimal ratio for simple coal (within$220 per ton).

Size classification

When choosing coal, it is important to know its dimensions. This indicator is encrypted in the grade of the mineral. So, coal happens:

- "P" - slab, which is large pieces over 10 cm.

- "K" - large, the size of which is from 5 to 10 cm.

- "O" - a nut, it is also quite large, with fragment sizes from 2.5 to 5 cm.

- "M" - small, with small pieces of 1, 3-2, 5 cm.

- "C" - seed - cheap fraction for long smoldering with dimensions of 0.6-1.3 cm.

- "Sh" - a piece, which is mostly coal dust, intended for briquetting.

- "P" - ordinary, or non-standard, in which there may be fractions of various sizes.

Properties of brown coal

This is the lowest quality hard coal. Its price is the lowest (about one hundred dollars per ton). Brown coal was formed in ancient swamps by pressing peat at a depth of about 0.9 km. This is the cheapest fuel, containing a large amount of water (about 40%).

In addition, lignite has a fairly low calorific value. It contains a large amount (up to 50%) of volatile gases. If you use brown coal for the furnace, then in terms of its quality characteristics it will resemble raw firewood. The product burns heavily, smokes heavily and leaves behind a large amount of ash. Briquettes are often prepared from this raw material. They have good performance characteristics. Their priceis in the range of eight to ten thousand rubles per ton.

Coal properties

This fuel is of better quality. Coal is a rock that is black in color and has a matte, semi-matte or shiny surface.

This type of fuel contains only five to six percent moisture, which is why it has a high calorific value. Compared to oak, alder and birch firewood, coal gives heat 3.5 times more. The disadvantage of this type of fuel is its high ash content. The price of coal in summer and autumn ranges from 3900 to 4600 rubles per ton. In winter, the cost of this fuel increases by twenty to thirty percent.

Storage of coal

If the fuel is to be used for a long period of time, it must be placed in a special shed or bunker. There it should be protected from direct sunlight and rain.

If the piles of coal are large, then during storage it is necessary to constantly monitor their condition. Fine fractions combined with high temperature and moisture can ignite spontaneously.