The increase in oil prices and the search for alternative energy sources not only led to the development of new technologies, but drew attention to another, no less useful raw material - coal. The most important for industry is coking coal. What is its value and where is it mined - described in this article.
What is coking coal
This is coal, from which, under coking conditions, coke of a certain strength and size is obtained. It is of great value to industry and is in great demand in many industries. So, coking coal is used as the main fuel in the production of steel and energy.
Coking coals differ from other fossil fuels in their ability to go into a plastic state and to sinter when exposed to high temperatures without oxygen.
The composition of coking coal
Concentrated and unenriched coking coal is characterized by low ash content (less than 10%), insignificant content of volatile components (from 15 to 37%) and sulfur (less than 3.5%). Compared to other types of coal, coking coals have a high combustion temperature and are characterized by a lower content of impurities. The ratio of constituent substances in different coal deposits may vary slightly. This is very important to consider in the process of coking. So, before the processing of coal, its composition, coking ability, sintering ability and other indicators are necessarily determined. On the territory of the post-Soviet space, the following types of coal are used for coking:
- K - coke.
- F - fatty.
- G - gas.
- OS - thin-caked.
- SS - highly sintering.
Coking process
By coking is meant the technological process of converting coal into coke. It consists of several stages. At the first stage, coal is prepared for coking. The mined coal is ground and special mixtures are formed - the mixture. The next stage is coking. It takes place in special chambers of a coke oven using gas heating. The prepared charge is placed in the oven for 15 hours, where all this time the temperature is raised to 1000ºC. As a result of this process, a “coke cake” is obtained.
During the twentieth century, coking technology has changed dramatically, which has allowed the development of new coal deposits.
According to estimates, about 10% of global coal mining goes through the coking process. This fact confirms the presence of high industry demand for coking coal.
What is the difference between coking and steam coal
The greatest value for the industry is provided by coking coal, which is used as a technological fuel in many industrial sectors of the economy. For example, for smelting cast iron. The main feature that distinguishes coking coal from energy coal is the presence of vitren. This is the ash component of coal, which is formed as a result of decomposition of plants in the absence of oxygen. Vitren's properties are its ability to melt and sinter under the influence of high temperature. Thus, microparticles of coal stick together in one dense mass. The higher the concentration of vitren, the higher the quality of coking of such coal.
The largest number of fusible substances is contained in such coal grades: coke, gas, fatty, lean sintering and coke fatty.
Coal brands
In nature, there are many varieties of coal, which differ in technical composition, indicators of sinterability and the release of volatile components. Only a few grades of coal are suitable for coking . But not all of them are suitable for sintering in its pure form. Sometimes some components are required. So, there are the following brands of coking coal:
- K is coke. When coking this brand of coal in its pure form, it produces conditioned metallurgical coke. To obtain the highest quality coal, other brands are added - fatty or gas.
- QOL - coke fat. It has the best coking properties, mainly used to produce coke without the addition of other types of coal. The composition of coke oven fat contains up to 30% volatile components. Vitren reflection is 1.3%. The thickness of the plastic layer is 18 mm. Without changes in the quality of coke, it is allowed to add to this brand up to 20% of COP, OS and KO.
- KO - coke lean. The thickness of the layer is 10-12 mm, the reflection of vitren - up to 1%. As a rule, this brand is not used separately, but only in combination with LCD and GZ charcoal.
- KOS - low coking low-metamorphic coke. During sintering, this type of coal forms a washable coke with low strength, which is why it is mainly used for sintering with other grades or to produce synthetic gas.
- KS - slightly coking coke. The thickness of the plastic layer is up to 9 mm. It is characterized by low caking. KS brand coal is used by coke enterprises as an exhaust component. It is also used in some areas of production for layered combustion.
- GK - gas coking. When coking give a well-fused coke, but with low mechanical strength. The sintering product is easily divided into small pieces. Typically, gas coal is used in mixtures with other coking coals.
The following coking coal grades are considered to be best for sintering: fatty, slightly sintering, gas, pure sintering and coke in its pure form. They contain the least amount of impurities, and they have high ductility.
Fields of application
The main purpose of coking coal is industrial fuel. During combustion, coking coal emits a large amount of thermal energy. So, the ignition temperature of this fuel is 470º. But burning is not the only way to extract useful properties from this fossil. There are many other sectors of the economy in which coking coal is used efficiently. The use of this natural resource in industrial processes makes it possible to obtain lead, molybdenum, zinc, germanium, sulfur, gallium and other chemical elements from it. Coal industry waste also has industrial applications. So, they are processed into refractory materials and abrasives. Building materials are also produced from waste.
In total, more than 300 varieties of products are made from stone fuel. Coal is used as the main material for the production of carbon-graphite structural elements, high-nitrogen acids, which are used in fertilizers. Effective use are substances that are released during the coking process. So, during dry distillation, coal tar and ammonia water are formed. They are also recyclable.
In addition, gaseous products that contain benzene, phenol, ammonia and toluene are released during coking. They serve as sources of other beneficial substances.
Mining of coking coal in Ukraine
Coking coal in Ukraine is mainly used by metallurgical enterprises. Thus, metallurgy accounts for about 90% of the total demand for this type of fuel. The country's mining industry provides coking coal with a domestic market of only 60%. The remaining 40% of the coal consumed is imported. The main supplier of coking coal to Ukraine is Russia.
In recent years, the country has seen an increase in demand for foreign raw materials. This is due to a decrease in domestic production. Also, the demand for domestic raw materials is falling due to a decrease in its quality, as metallurgical plants cannot use coal with a high sulfur content.
In Ukraine, coking coal is mined in the basins: Donetsk, Lviv-Volynsky, and Dnieper. The largest amount of coal reserves is concentrated in Donetsk, Lugansk and Dnepropetrovsk regions. Currently, due to political instability, coking coal production in eastern Ukraine has been suspended.
Coal mining in Russia
In Russia there are large deposits of coal. According to figures, the country is one of the first places in the world in coal reserves. More than 67% of them are coal. Of these, 10% are coking coal.
In Russia, coking coal is mined in the basins: Kuznetsk, Pechora, South Yakutsk, Donetsk and Kizelovsky. The first two pools produce the most coal.
Coking coal reserves in the Russian Federation amount to 47.3 billion tons. However, only a small fraction is usable. In recent years, coking coal production in Russia is at the level of 70 million tons per year. This is enough to provide the country's industrial enterprises with raw materials.
Coking coal in Russia is mined at a steady pace. An increase in coal production will occur if demand for this type of raw material increases due to the development of metallurgical and related sectors of the Russian economy.
Prospects for the coking coal market
In the coming years, the Russian coal industry is waiting for changes. Key areas of industry development will concern the vertical coal production system. So, state policy provides for the creation of small and medium-sized power facilities on the basis of coal mines. It is also planned to install equipment at coal mining enterprises that will allow processing coal into environmentally friendly synthetic fuels.
As for sales volumes, the demand for coking coal in Russia will grow. The fact is that in addition to steel mills, coke uses non-ferrous metallurgy and many other industries. So, for the production of 1 ton of pig iron, about 0.4 tons of coke is needed. And alternative technologies that allow it to be replaced with a more profitable resource are applied to a limited extent.
Global Coking Coal Market Trends
To date, many coal companies in all countries are experiencing a crisis in the decline in prices for coking coal. This problem is exacerbated by states that supply coke in excess. Also, the desire of buyers to reduce costs has a great influence on prices. Another unfavorable situation arises from the desire of steel producers to reduce production costs. In Europe and China, the demand for coking coal continues to grow, but this is due to the production of products of the highest categories. But in general, the volume of purchases of raw materials in the world market is falling.
The situation with energy raw materials in the US market has stabilized a bit. But the price of it continues to fall due to lower demand for steel. As a result of this, coking coal production in the USA and European countries may be reduced.
But experts predict an increase in imports of energy raw materials in India. In terms of coking coal imports, this country ranks third in the world.
Cost of raw materials
In the second quarter of 2015, coking coal prices decreased. Large global companies offer raw materials at a price that is 5-10% lower than in the first quarter. So, the South African company Anglo American offered Japan the highest quality coking coal at $ 116 per 1 ton. The average price for 1 ton of coking coal is $ 117.