RU2537151C1 - Preparation of free-burning coal - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to a method of preparation of free-burning coal with the content of volatile substances not exceeding 16% whereat the said coal is heated to 200-395°C to destruct heat-sensitive coal lumps to be cooled and classified thereafter. Anthracite and/or hard coal are used as the free-burning coal. Heated coal is cooled at an ambient temperature.

EFFECT: stabilised grain size, simplified process, higher calorific value.

5 cl, 1 dwg, 4 tbl, 4 ex

Description

The invention relates to the field of preparation of non-sintering coals for burning and can be used in ferrous and non-ferrous metallurgy for ore sintering, in shaft furnaces, as well as in the energy and chemical industries.

Fossil coals are coals of various grades and various qualities. One of the most important differences between coals is sintering coals, giving coke for metallurgical production (metallurgical coals), and non-sintering coals and suitable mainly for ore sintering, as well as for heating and energy production (energy coals).

Shortage of coking coals, their insufficient quality and high cost of coking are an important problem in metallurgy. This raises the question of saving coke from its main consumer - the metallurgical industry. In particular, the option of replacing coke with a much cheaper coal — lean coal or anthracite — may be promising.

Lean coal and anthracite are non-sintering coals.

The use of lean coals does not require additional training and capital investments. The cost of coal is more than two times lower than the cost of coke, and transportation is cheaper due to the greater bulk density. This makes the cost-effectiveness of their use obvious if it does not lead to a deterioration in the process performance and product quality.

The moisture content in lean coals ranges from 2-7%, which does not go beyond the indicators for coke.

The content of non-volatile carbon is very high and close to coke.

The yield of volatile components on a dry ashless mass is approximately 8-16%.

The reflection coefficient of vitrinite lean coal is from 1.5 to 2.59%; no sintering ability.

Skinny coals are characterized by a low yield of tarry substances. For lean coal from the Krasnobrodsky open pit, it is 0.14-0.5%, and from the Krasnogorsk opencast, traces. Consequently, the use of lean coal will not lead to overgrowing of the gas paths of metallurgical units.

The calorific value of dry ashless mass for lean coals is 35200-36500 kJ / kg and depends mainly on the chemical composition of coal, which in turn is determined by the degree of metamorphism. The heat is generated mainly due to the combustion of hydrocarbons contained in coal and hydrogen, so the heat of combustion can be higher than that of coke.

Comparison of the properties of lean coals and metallurgical coke shows that the strength of lump lean coal is lower than that of coke, and crushability and abrasion are higher. Coals are characterized by a lower flash point and higher calorific value. Coals have a lower porosity, but their reactivity is close to the reactivity of coke.

Thus, the characteristics of lean coal, in general, meet the requirements for metallurgical raw materials as fuel and carbon-containing agent.

Lean coal is used mainly in the electric power industry and in the household sector; subject to low ash content, they can be used to produce carbon fillers in electrode production.

Skinny coals are sometimes called "semi-anthracite".

However, the following circumstances must be considered. Lean coal is a natural raw material, its properties can vary significantly for different parties. Therefore, when it is used in metallurgy, special monitoring of indicators at coal enterprises is necessary.

The low mechanical characteristics of coal relative to coke require the development of a technology for its preparation before technological use.

Anthracites, like lean coal, are natural raw materials. Anthracites combine coal with a vitrinite reflectance of more than 2.59%. When the volatiles yield is less than 8%, anthracite also includes coals with a vitrinite reflectance of 2.2 to 2.59%.

Anthracite differs from other types of coal in its high content of bound carbon (91-98%), low moisture, sulfur, and volatile substances (2-9%), and high specific heat of combustion. Anthracite burns without smoke and flame, with high heat dissipation, does not sinter. It has a high density of organic matter (1500-1700 kg / m ³ ) and high electrical conductivity. The hardness according to the mineralogical scale is 2.0-2.5.

Currently, in addition to its use in the energy sector, anthracite is used for ferrous and non-ferrous metallurgy, as well as for the production of adsorbents, electrodes, electrocorundum, microphone powder, thermoanthracite, etc.

The requirements for the quality of anthracite are the highest, because even a relatively slight deterioration of some properties of anthracite often adversely affects the process and production.

Given the above, natural non-sintering coals (lean coals and anthracites can be used instead of coke in certain areas of industry). The use of such coals will reduce the consumption of expensive coke.

However, the problem is the insufficient strength of pieces of non-sintering coal (lean coal and / or anthracite) during their heating during technological use.

Some pieces of coal and / or anthracite are destroyed with the formation of fine fractions, which leads to disruption of the hydraulic regime in the furnace during fuel combustion and to chemical underburning of the fuel, and a decrease in furnace productivity.

A known method of heat treatment of coal (USSR author's certificate No. 467089) in vortex chambers with a gas coolant, followed by isothermal exposure, in which the heat treatment of coal is carried out at a temperature of 450-550 ° C and the oxygen content in the gas stream of 0.5-1.0%.

This invention allows to increase the heat of combustion of small fractions of coal and brown coal with a high volatile content. Accordingly, this invention is not effective when using large fractions of pieces of coal with a low yield of volatile substances. In addition, the need for heat treatment of coal at temperatures of 450-550 ° C leads to significant energy consumption during the implementation of the method.

A known method of preparing raw materials for blast furnace smelting (USSR author's certificate No. 1129255), in which fuel briquettes are used as fuel, into which coal is preheated to 200-250 ° C before briquetting.

In this method, by preheating the coal to 200-250 ° C, the binder works better.

Those. this method is applicable to coals with a high content of volatile, easily removable with little heat; for fine-grained coal fractions used to form fuel briquettes.

A known method of preparing solid fuel for combustion (USSR author's certificate No. 1170226), in which additional heating of the fuel is carried out - coal dust by directly affecting the fuel of the torch. Those. The known method is applicable only to pulverized coal fractions at high heating temperatures - up to 900-1000 ° C.

A continuous method for processing non-coking coal is known to produce stable semi-coke (options) according to RF patent No. 2098450.

In the method according to patent No. 2098450, non-coking coals are heated to temperatures of 400-480 ° C in order to evaporate moisture and remove part of the volatile substances. In this method, a change in the structure of coal occurs, which, after heating, goes into semicoke.

The area of use of semicoke is narrower than coal. Semi-coke can be used in the production of coke as part of a charge, as a fuel in the production of ferroalloys, and in ore sintering.

The disadvantage of the method according to patent No. 2098450 is the increased cost of its implementation associated with the need to heat coal to temperatures of 400-480 ° C, as well as the complexity of the method, including due to the need to capture volatile substances.

A known method of preparing low-grade coal (JP 63210192 A, 08/31/1988) with a volatile content of more than 30%, in which the coal is dried at a temperature of 180-400 ° C for 2-10 minutes with gas. Then the coal is cooled with water in 2 stages to 60 ° C.

The method according to the document JP 63210192 A, 08/31/1988 is selected as the closest analogue (prototype).

The disadvantage of the closest analogue is the inefficiency of the method, non-environmental and complexity.

The technical result achieved by the claimed invention is the stabilization of the particle size distribution of fuel from non-sintering coals due to the preservation of heat-resistant fractions of pieces of fuel during combustion; simplification of the preparation of non-sintering coals; increase in calorific value of fuel; ensuring high efficiency of the method.

The claimed technical result is achieved due to the fact that in the method of preparing non-sintering coal with a volatile substance content of not more than 16%, the non-sintering coal is heated to a temperature of 200-395 ° C to destroy non-heat-resistant components of the pieces of coal, followed by cooling and classification.

As non-sintering coal, anthracite and / or lean coal are used.

The heated coal is cooled at ambient temperature.

After cooling, non-sintering coal is subjected to mechanical stress.

The classification of coal is carried out after mechanical action or simultaneously with it.

The feedstock is lean coals or anthracites, which have common properties - not sintering, low volatile content (not more than 16%).

A common disadvantage of non-sintering coals (lean coals and anthracites) is their insufficient heat resistance. When using natural non-sintering coals as a fuel as a result of their heating, non-heat-resistant pieces of coal are destroyed into smaller particles. When heated, fuel changes its initial particle size distribution (grain, sieve) due to the destruction of the original pieces of fuel, including non-heat-resistant components. With the spontaneous destruction of such pieces of fuel in the furnace, the hydraulic mode of fuel combustion is disrupted, and the productivity of the furnace is reduced.

In addition, the content of non-heat-resistant inclusions in natural non-sintering coals is not constant, and therefore the technological properties of fuels based on natural non-sintering coals are difficult to predict. In this regard, the use of natural non-sintering coals as a fuel without special preparation is impractical.

The reason for the destruction of part of the bulk material from non-sintering coals is the thermal stresses that occur when the bulk material is heated. Flake graphites and half-graphites that break down into thin plates and flakes, as well as pieces from petrographically inhomogeneous layered formations, are non-heat-resistant.

In the inventive method for the preparation of non-sintering coals for their technological use, the coals are heated to temperatures of 200-395 ° C. At such temperatures, lean coal and anthracite are not converted to semi-coke, thereby preserving its wide area of use - firing processes, mine smelting of non-ferrous metal ores as fuel in cupolas and for other processes.

When coal is heated to temperatures of 200-395 ° C, non-heat-resistant inclusions (components) of coal are destroyed, which are easily removed, for example, during classification after heating.

Removal of volatiles practically does not take place; the amount of volatiles before heating of coal and after its heating practically does not change.

Moisture evaporation from coal occurs almost completely at temperatures of 100-200 ° C. Those. at temperatures up to 395 ° C, coal is practically free of moisture.

Energy costs for the preparation of non-sintering coal according to the claimed method is lower than in the known methods.

The authors' studies showed that a significant part of non-heat-resistant components is destroyed by heating non-sintering coals to temperatures in the range from 200 to 395 ° C.

Heating to such temperatures, firstly, reliably ensures the destruction of non-heat-resistant components, secondly, it does not require significant energy costs, and thirdly, it does not require the use of special cooling, because cooling in this case is carried out naturally, which significantly improves the environmental friendliness of the method. It should be noted that when heated to temperatures of 200-395 ° C, there is no release of pyrolysis chemical products from non-sintering coals and, therefore, there is no cost of trapping them.

Figure 1 shows the dependence of the total output sieve product (anthracite) in relation to the size of the holes of the sieve.

Curve 1 - for non-heat-treated anthracites.

Curve 2 - for anthracites that have been trained according to the claimed method.

It can be seen that the volume of the oversize product after heat treatment decreased by about 10-12% due to the destruction of non-heat-resistant components of anthracite, which led to a decrease in large pieces of anthracite and the appearance of smaller pieces.

Also, the studies of the authors showed that when preparing non-sintering coals with a volatile content of up to 16% according to the claimed method, the amount of volatile substances before and after preparation is practically unchanged.

After heating the initial non-sintering coals to temperatures of 200-395 ° C and subsequent natural cooling, it is advisable to subject the non-sintering coals to mechanical stress. The main destruction of pieces of coal as a result of the destruction of non-heat-resistant components occurs spontaneously when they are heated. However, after heating, it is advisable to carry out a mechanical action, since as a result of mechanical action, the pieces of coal are additionally destroyed due to the additional destruction of non-heat-resistant components.

After mechanical action or simultaneously with it, the classification of coals is carried out in order to select fractions of coal in accordance with their possible technological use.

Studies of the authors showed that during the technological use of fuel that has been prepared in accordance with the claimed method, there is practically no further decomposition of pieces of fuel in the furnace, therefore, non-sintering coal prepared according to the claimed method can replace metallurgical coke used for the corresponding technological needs.

The kinetics of thermal destruction of lean (non-sintering) coals can be judged by the data given in table 1, by the change in the percentage of the class of coal 25-100 mm with stepwise heating from a temperature of 20 ° C to 1000 ° C.

Two types of coal were taken for testing - lean coal and anthracite, as well as metallurgical coke. Characteristics of coal and coke are given in the same table.

From the data of table 1 it can be seen that an active decrease in the grade of 25-100 mm in lean coals and anthracites occurs with an increase in temperature from 20 to 200 ° C. At such temperatures, the moisture evaporates actively until it completely evaporates and the non-heat-resistant components of coal are actively destroyed.

Further to temperatures from 200 to 400 ° C, a decrease in the grade of 25-100 mm in lean coals and anthracites practically does not occur. At these temperatures, the removal of volatiles from lean coal and anthracite practically does not occur. At such temperatures, insignificant additional destruction of non-heat-resistant coal components occurs.

A further decrease in the content of the class 25-100 mm in lean coals and anthracites occurs at temperatures from 700 to 1000 ° C, which is mainly due to the loss of volatile substances.

The preparation of coal in accordance with the claimed method when using coal with a yield of volatiles of more than 16% is impractical in connection with the following.

When heating coal with volatile substances up to 16% to temperatures of 200-395 ° C, there is practically no removal (emission) of volatile substances. This is confirmed by the information provided in the source “Scientific Foundations of Coke Production”, Proceedings of the meeting (Sverdlovsk, 1965), Metallurgy Publishing House, 1967 (Appendix 1).

From table 1 of the source “Scientific Basics of Coke Production” on page 126 it is seen that OS grade coal is characterized by a yield of volatile substances of less than 16% (14, 39%); coals of grades D, G, G are characterized by a yield of volatiles of more than 30%.

From table 2 of the source “Scientific Foundations of Coke Production” on page 128, it is seen that when the OS brand coal is heated to 400 ° C, there is practically no yield of thermal degradation products, gas and gas gasoline, or pyrogenetic water. In this case, when heated from 250 to 400 ° C, there is a significant yield of thermal degradation products, gas and gas gasoline, as well as pyrogenetic water in coal grades D, G, Zh.

This means that when heated to temperatures from 250 to 400 ° C of coal, characterized by a yield of volatiles of more than 30%, there is a significant release of the above products into the environment. It should be noted that phenols, which belong to hazard class II, also belong to the distinguished products of thermal degradation.

Therefore, there is pollution of the surrounding space. Therefore, it is necessary to provide additional measures to capture products released during heating from coal and their utilization, which will significantly complicate the preparation of such coals for use as fuel.

In addition, when heating coals with the release of volatiles of more than 30% to temperatures of 400 ° C, there is a sharp weight loss (from 1.5 to more than 4%) of the solid residue, i.e. intense thermal degradation of coals takes place (the penultimate and last paragraphs of p. 128 of the source “Scientific Foundations of Coke Production”, Fig. 3 on p. 129).

From the source “Technology of carbon-graphite materials”, E.F. Chalykh, M., 1963, State Scientific and Technical Publishing House of Literature on Ferrous Metallurgy and Non-Ferrous Metallurgy on page 96 (Appendix 2) it is known that the weight loss of anthracite when heated from 200 to 400 ° C is 0.76% (table 21) .

Those. the weight loss of anthracite having a yield of volatiles of less than 8% when heated to 400 ° C is significantly less than that of coal with a yield of volatiles of more than 30%.

Moreover, the weight loss of anthracite and coal with the release of volatiles of more than 30% is due to various reasons.

Anthracite loses weight when heated to 400 ° C only due to the removal of moisture (since organic matter at such temperatures is not removed from anthracite), and coal with a volatile content of more than 30% lose weight precisely due to the removal of organic components.

After removal of more than 30% of organic components from coal with volatile substances, the percentage of non-combustible mineral content increases. In this connection, after heating coals with a volatile substance content of more than 30% to temperatures of 400 ° C, their calorific value decreases due to the intensive removal of organics.

On the contrary, when heating non-sintering coals with a volatiles yield of not more than 16% when heated to 400 ° C, no organic components (combustible components) are removed, therefore, there is no loss of calorific value of such coals when they are heated to temperatures of 400 ° C.

It should also be noted that due to the intensive removal of volatiles when heated to temperatures of 400 ° C from coals with a volatiles yield of more than 30%, more intense decomposition of pieces of coal takes place due to more extensive cleavage of the least strong bonds in pieces of coal. Those. the initial pieces of coal break up into a large number of small pieces that are smaller than pieces of coal formed during the decay of coal with a volatile matter content of not more than 16%.

Small fractions of coal have limited technological use than larger ones.

In addition, when heating large volumes of coal with an output of volatiles of more than 30%, it is necessary to use special means or technological parameters of the coal preparation process that ensure the explosion safety of the process, since the intensive exit of volatiles increases the risk of gas accumulation in the volume of coal and the risk of explosion.

Thus, the result of the preparation of the inventive method of non-sintering coal with a yield of volatiles of not more than 16% compared with the same preparation of coal with a yield of volatiles of more than 30% is that as a result of such preparation, a sufficiently large lump coal is obtained, which can be used as replace metallurgical coke and use it as fuel for almost any technological need. After such preparation, coal does not lose its original calorific value, i.e. The claimed method is effective. In addition, the claimed method is environmentally friendly, because occurs without emission of gases into the atmosphere; is simple, because the implementation of the proposed method does not require the use of special means for capturing the emitted components of coal. The inventive method is safe (explosion proof).

An unobvious effect is the following. Heating to a temperature of 200-395 ° C non-sintering coals with a yield of volatile substances up to 16% and heating of non-sintering coals with a release of volatile substances above 16% gives a different result.

When heating non-sintering coals with a yield of volatiles up to 16% to temperatures of 200-395 ° C after cooling and classification, coal with high calorific value is obtained, strong, capable of replacing metallurgical coke. Moreover, when preparing such coals according to the claimed method, it is not necessary to apply additional environmental protection measures and measures ensuring the safety (explosion safety) of the process.

On the contrary, when non-sintering coals are heated to temperatures of 200-395 ° C with a yield of volatiles above 16%, after cooling and classification, coal is obtained consisting of small fractions (which determines its limited use), with a low calorific value (not allowing the use of such coal as a substitute for metallurgical coke). At the same time, when heating such coals to temperatures of 200-395 ° C, there is a significant deterioration in the ecology and safety of the process. Therefore, to prepare such coals by heating them to temperatures of 200-395 ° C, technical measures are required to ensure environmental safety and explosion safety of the process.

Thus, the claimed method with its apparent simplicity allows to achieve the claimed technical result, therefore, the claimed method meets the condition of patentability "inventive step".

The inventive method is illustrated by the following examples.

Example 1

The tests were carried out with high-grade anthracite grades 20-120 mm.

Technical analysis and calorific value of anthracite concentrate are given in table 2.

Where:

W ^a - analytical moisture;

A ^d - dry ash content;

V ^r - exit of volatile substances to working condition;

V ^daf — yield of volatile substances to a dry ashless state;

- общее содержание серы на сухое состояние; $$S_t^d$$

- total sulfur content on a dry state;

- органическая сера на сухое беззольное состояние; $$S_o^{daf}$$

- organic sulfur to dry ashless state;

- органический углерод на аналитическое состояние; $$C_o^a$$

- organic carbon for an analytical state;

- органический водород на аналитическое состояние; $$H_o^a$$

- organic hydrogen in the analytical state;

- высшая теплота сгорания рабочего состояния топлива; $$Q_s^r$$

- higher heat of combustion of the working state of the fuel;

- высшая теплота сгорания сухого беззольного топлива. $$Q_s^{daf}$$

- the highest calorific value of dry ashless fuel.

The results show that the studied anthracite belongs to anthracite of thermal origin and therefore has a low yield of volatile substances of 2.81%. The studied anthracite has a low ash content, low sulfur content and a high (higher than that of metallurgical coke) calorific value.

Table 3 shows the particle size distribution (by dry weight) of the original anthracite and the same anthracite, which was prepared according to the claimed method.

From table 3 it is seen that the original anthracite has a high yield of large classes and, therefore, is characterized by high mechanical strength. After preparation according to the claimed method, thermal destruction of part of the bulk material occurs with an increase in the number of fine fractions. The content of pieces of anthracite with a size of less than 20 mm increased from 5.2% to 20.3%, i.e. increased by 15%.

After preparing anthracite according to the claimed method, its technical analysis showed that the ash content on dry weight, the yield of volatiles, the total sulfur content, and the total phosphorus content turned out to be close in all classes to the indices of the initial anthracite.

After classifying the prepared anthracite, each class is sent to the appropriate technological use.

The authors' studies showed that with the technological use of the prepared anthracite, there is practically no further destruction of the pieces of anthracite, respectively, a stable mode of operation of the technological unit is ensured.

In technological applications, anthracite fines (0-10 mm) prepared according to the claimed method, anthracite turned out to be a complete substitute for coke breeze during the agglomeration of iron and nickel ores. The consumption of anthracite fines is carried out with a coefficient of 0.95-1.0 compared with coke fines.

The 10-20 mm fraction of prepared anthracite is a good substitute for coke of the 10-25 mm fraction in the production of high-carbon ferrochrome. Compared with coke, 10-25 mm has a lower sulfur content and therefore allows to obtain low-sulfur high-carbon ferrochrome.

Low ash, low humidity, low sulfur content, good heat resistance are the main advantages, allowing 100% to replace the coke nut with anthracite fraction of 10-20 mm prepared according to the claimed method.

Example 2

In a shaft furnace of the OSM-2725 type for firing dolomite with an inner diameter of 3.5 m and a height of 14.2 m, dolomite was fired to the content of CaO + MgO oxides in the calcined product to 95% or more.

The initial dolomite was characterized by a MgO content of at least 19.0% and an average CaO content of 33.0%.

Coke fractions of 25-40 mm were used as fuel.

Specific consumption of coke 200 kg / t of dolomite. The blast volume was up to 10,000 m ³ / h. The temperature in the firing zone was 1700-1750 ° C. The furnace capacity for dolomite loaded into the furnace was 300-340 t / day.

Coke was replaced with anthracite grade 25-40 mm and anthracite grade 25-40 mm, trained according to the claimed method.

With a 100% replacement of coke with anthracite of 25-40 mm class, the furnace capacity for feed dolomite decreased to 180-250 kg / t. The quality of the calcined dolomite also decreased - the number of "underburning" increased, there was sintering of pieces of dolomite. The temperature of the exhaust gases sharply increased, which caused a deterioration in the environment and working conditions and was associated with chemical underburning of the fuel (incomplete combustion of fuel).

When replacing 50% of coke with anthracite, the indices characteristic at 100% use of coke as fuel were restored.

With a 100% replacement of coke with anthracite, which was prepared according to the claimed method, fuel consumption decreased to 190 kg / t of dolomite, furnace productivity remained at the level of 310-340 t / day for loaded dolomite. The quality of the calcined dolomite was maintained at a level characteristic of work on 100% coke. Sintering of pieces of dolomite among themselves almost disappeared.

Thus, the anthracite prepared according to the claimed method, allows you to completely replace the coke used as fuel in the firing of dolomite while maintaining the performance of the shaft furnace, characteristic of the furnace at metallurgical coke.

Example 3

Carried out the firing of dolomite with coke, lean coal and lean coal, trained in accordance with the claimed method.

In a shaft furnace of the OSM-2725 type for firing dolomite with an inner diameter of 3.5 m and a height of 14.2 m, dolomite was fired to the content of CaO + MgO oxides of up to 95% or more in the calcined product.

The initial dolomite was characterized by a MgO content of at least 19.0% and an average CaO content of 33.0%.

Coke fractions of 25-40 mm were used as fuel.

Specific consumption of coke 200 kg / t of dolomite. The blast volume was up to 10,000 m ³ / h. The temperature in the firing zone was 1700-1750 ° C. The furnace capacity for dolomite loaded into the furnace was 300-340 t / day.

Coke was replaced with lean coal of class 25-40 mm and lean coal of class 25-40 mm, which was trained according to the claimed method.

With the complete replacement of coke with lean coal, disorders appeared in the technology of firing dolomite. The temperature of the exhaust gases has risen, the productivity of the loaded dolomite has decreased by more than 34%. There was sintering of pieces of dolomite among themselves. It was found that during the heating of coal on the way to the combustion zone, partial pieces of coal are destroyed and the result is the appearance of fines of coal and violation of the hydraulic regime when applying air blast, oxygen leakage, incomplete combustion (the content of CO in the top gases increased from 5-6 to 15-20%), i.e. chemical underburning of coal was observed.

After replacing lean coal of a fraction of 25-40 mm with such a fraction of lean coal, which was prepared according to the claimed method, the fuel consumption for firing dolomite decreased, the furnace productivity was restored, as in coke; the temperature of the exhaust gases also decreased to temperatures, as when using coke.

Table 4 shows the characteristics used in the firing of dolomite coke, lean coal, lean coal, trained according to the claimed method, the performance of the furnace.

As can be seen from table 4, the results of firing dolomite on anthracite and lean coal, trained according to the claimed method, are similar.

Those. when firing dolomite, it is possible to completely replace coke with anthracite and lean coal, which have been prepared according to the claimed method.

Example 4

Melting of cast iron in cupolas.

Melting was carried out in 20-ton cupolas with a capacity of 20 tons / hour at a fuel consumption of metallurgical coke of 12% of the melt.

When replacing metallurgical coke with anthracite of class 50-120 mm, it was possible to maintain melting indices only with a partial (up to 15%) coke replacement. When replacing in a larger amount, frustration in the course of the melting and a decrease in the productivity of the cupola began to be observed.

Replacing 100% of the coke of the working heads with anthracite grade 50-120 mm, trained according to the claimed method, deviations in the technology of smelting were not observed. At the same time, the temperature of cast iron increased by 30-40 ° C, the quality of casting increased, the yield of casting scrap decreased. Cupola productivity increased by 5%.

Thus, the invention provides the possibility of 100% replacement of metallurgical coke with non-sintering coal, which has been prepared according to the claimed method, in iron foundry cupolas.

In all examples, with the technological use of non-sintering coals prepared according to the claimed method, the destruction of pieces of fuel in the furnace was not observed.

The area of use of non-sintering coals (lean coal and anthracite) prepared according to the claimed method, when used as fuel in processes with layer-by-layer burning of fuel. Due to the high density, non-sintering coals prepared according to the claimed method cannot be used in blast furnaces.

Claims (5)

1. The method of preparation of non-sintering coal with a volatile substance content of not more than 16%, in which the non-sintering coal is heated to a temperature of 200-395 ° C to destroy non-heat-resistant components of the pieces of coal, followed by cooling and classification. 2. The method according to claim 1, characterized in that anthracite and / or lean coal are used as non-sintering coal. 3. The method according to claim 1, characterized in that the cooling of the heated coal is carried out at ambient temperature. 4. The method according to claim 1, characterized in that after cooling, the non-sintering coal is subjected to mechanical action. 5. The method according to claim 1, characterized in that the classification of coal is carried out after mechanical action or simultaneously with it.

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