EA031479B1 - Method of producing coke - Google Patents

Abstract

The invention is related to the field of metallurgical coke production and can be used in non-ferrous metallurgy, in particular, for producing nickel matte. The technical result of the proposed invention is optimization of the coke production process due to preparation of charging material for carbonization, and improvement of physical and chemical properties of coke (low ash content, higher sulphur content, higher reactivity, higher mechanical strength) for ensuring its efficient use in nickel matte production, and hence higher efficiency of nickel matte production due to higher yield of nickel and lower coke consumption. Proposed is a method for producing coke from a charge comprising a mixture of coals of various technological grades and mixtures of petroleum cokes of size less than 25 mm with further carbonization of the obtained mixture. Petroleum cokes with different volatile-matter yield are mixed in a preset proportion, the share of petroleum cokes with volatile-matter yield in the range from 7 to 13.9% being not more than 40% of the total charge volume, the petroleum coke used has a sulphur content of 1.1 to 6% and an ash content of 0.1 to 2%, while the amount of poorly coking or non-coking coals is reduced respectively, all components of the charge are crushed together and then the charge is fed to coke batteries for layerwise carbonization.

Description

The invention relates to the field of metallurgical coke and can be used in non-ferrous metallurgy, in particular for the production of nickel matte. The technical result of the invention is the optimization of the technological process of coke production due to the preparation of the charge for coking, as well as the improvement of the physico-chemical properties of coke (low ash, high sulfur content, increased calorific value, increased reactivity, increased mechanical strength) to ensure its effective use in the production of nickel matte, as well as, as a consequence, an increase in the efficiency of production of nickel matte, due to velicheniya exit nickel and reduce consumption of coke. A method is proposed for producing coke from a mixture containing a mixture of coal of various technological brands and a mixture of petroleum coke with a fraction of less than 25 mm, with further coking of the mixture obtained. Oil cokes with different volatile substances are mixed in a given proportion, and the share of oil cokes with volatile substances in the range from 7 to 13.9% is no more than 40% of the total charge, petroleum coke with sulfur content of 1, 1 to 6% and ash content from 0.1 to 2%, with a corresponding decrease in slightly caking or non-caking coal, all components of the charge are crushed together and then the charge is fed to the layer of coking in coke oven batteries.

031479 B1

The invention relates to the field of metallurgical coke and can be used in non-ferrous metallurgy, in particular for the production of nickel matte.

When using coke to restore non-ferrous metal ores (lead, tin, copper) in shaft furnaces, its mechanical strength, ash content and fines content, as well as its reactivity are subject to requirements that differ from the requirements for blast-furnace coke. In particular, metallurgical coke is used in the smelting of oxidized nickel ores. This allows you to reduce or completely eliminate the sulfur-containing additives required by the conditions of the technological process, increasing the cost and the cost of finished products.

A known method for producing high-sulfur petroleum coke (certificate of authorship No. 254471, priority date 09/28/1967, publ. 10/17/1969, class IPC C02B 55/02). The known method suggests, with the aim of expanding the resource base, the use of high-sulfur petroleum coke and further coking with coking coal, and after coking, the process of calcination is carried out at a temperature of 900-1000 ° C.

The disadvantage of this method is the duration of the process, as it requires an additional operation of the calcination of coke. The process is more complicated as it requires additional equipment for calcining the coke, as well as additional operations for unloading the coke, cooling it, and then loading it into the furnace for calcining. More costly, in terms of process economics, and ineffective.

Famous patent of the Russian Federation No. 2124548, according to which from 0.1 to 6% of petroleum coke fines are introduced into the coal charge (a mixture of different technological grades). The objective of this invention is aimed at expanding the resource base of coking, as well as the charge of a special composition, to obtain blast-furnace coke, intended for smelting ferrous and conditionally non-ferrous metals.

The disadvantage of this method is the reduction of the mechanical strength of the blast furnace coke in terms of M25 and the increase in the abrasion of coke in terms of M10. In the case of use in non-ferrous metallurgy, the use of a known method will lead to an increase in the cost of the process and a decrease in economic efficiency, a decrease in nickel extraction, in the production of nickel matte, an increase in coke consumption.

Known additive coking (patent number 2355729, priority date 02/26/2008, publication date 05/20/2009, class IPC C 5 5 57/04). The invention relates to the field of metallurgical coke for non-ferrous metallurgy. The proposed use of petroleum coke, with the release of volatile substances in the range of more than 14 and less than 25%, as a coking additive to the coal mixture used for the production of metallurgical coke. Replacing the scarce grade K coal with a cheap by-product - petroleum coke allows the utilization of petroleum coke and reduces the cost of the coking process.

A disadvantage of the known coking additive is the inconstancy of the composition, which is confirmed by the spread of the values of the sintering properties on the Horn index, as well as on the IGI-VUHIN index. The inconstancy of the composition of the coking additive depends on the imperfection of the coking process at the delayed coking unit of the UT. This inconsistency in the composition of the coking additive leads to instability in the quality of coke in terms of M25 and M10, especially with a large share of the participation of the coking additive in the charge. The replacement in the charge for coking the highly deficient, high-tech K grade coals is conditional, due to the fact that the coking additive has low coking and sintering properties that do not allow production of coke with mechanical strength M25 and M10 required for nickel production. Only partial replacement of extremely scarce, high-tech K-grade coals with a coking additive, such as an additive to coal blends, in small amounts of 1-7%, in the production of blast-furnace coke, allows to produce coke that meets the requirements of blast-furnace smelting.

A known method for producing coke for smelting non-ferrous metals is EP 022518 with a patent publication date of 01/29/2016 (registration number and application date set by the patent office of the state party to the Eurasian Patent Convention, country code, application No. 2012000234 RU, priority date 22.10.2012, publication date 04/30/2014, class IPC C10B 57/04). When using the known method, the coke additive with a sulfur content of 3.5-4.5% is mixed with coal concentrates of gas fat coals, gas fat lean coals, gas coals, coke low-caking coals, with a ratio of components in the mixture, wt.%: Coke additive: 50-70, coal charge: 30-50.

The disadvantages can be determined that when used in the sintering part of the coal charge low on the technological value of coal, such as coal grades G and GZHO, having a low level of sintering, as well as low reflectivity of vitrinite, and as an emaciated additive - coal KSN, In this case, the resulting coke has low mechanical strength parameters for M25 and high abradability of M10. In addition, from a mixture containing coal grades G and GZHO, KSN, a low yield of gross coke is obtained due to the high yield of volatile substances of the charge.

The technical result of the invention is the optimization of the technological process of coke production, due to the preparation of the charge for coking, as well as the improvement of the physicochemical properties of coke (low ash content, high sulfur content, increased calorific value

- 1 031479 ability, increased reactivity, increased mechanical strength) to ensure its effective use in the production of nickel matte, and, as a result, increase the efficiency of production of nickel matte by increasing the yield of nickel and reducing coke consumption.

The technical result is achieved by improving the quality characteristics of coke on the mechanical strength of M25 and M10, by reducing the ash content by almost two times compared with metallurgical coke and increasing the sulfur content by almost five times compared to metallurgical coke, as well as improving the calorific value coke, by reducing the ash content of coke.

A method is proposed for producing coke from a mixture containing a mixture of coal of various technological brands and a mixture of petroleum coke with a fraction of less than 25 mm, with further coking of the mixture obtained.

The difference is that petroleum coke, with a different yield of volatile substances, is mixed in a predetermined proportional ratio, and the share of participation of petroleum coke with the release of volatile substances in the range from 7 to 13.9% is not more than 40% of the total charge, petroleum coke with sulfur content from 1.1 to 6% and ash content from 0.1 to 2%, all components of the charge are crushed together and then the charge is fed to layer coking in coke oven batteries, and the sulfur content in the finished product is not lower than 2.0 and not higher than 5.0.

Using the LH scheme (crushing of the charge), crushing the joint of all components makes it possible to obtain a uniform particle size distribution of the coal charge, to improve the contact of the grains during layered coking and reduce the development of cracks in the coke. Moreover, it is the use of petroleum coke with a fraction of less than 25 mm that is essential and allows for the joint crushing of all components, since most of the components of the charge have the same crushability. Thus, the coke production process is optimized due to the preparation of the charge for coking, and also the physical and chemical properties of the coke are improved. It turns out that coke, which is stable in its quality characteristics, meets the requirements for mechanical strength of M25 and M10. Signs of the formula are in causal connection with the stated technical result and are significant.

The work of the Russian metallurgical enterprises in the conditions of sanctions imposed on the Russian Federation, and the fierce competition makes the issue of production economy, with the condition of preserving the quality of the products, highly important.

The proposed method is aimed precisely at improving the efficiency of coke production for non-ferrous metallurgy. The peculiarities of nickel matte production are the solution of the problem of maximum extraction of nickel into matte, reduction of nickel losses with slag, and transfer of waste rock into slag. As practice shows, the enterprises of non-ferrous metallurgy for this use sulfur-containing additives required by the conditions of the process and, of course, they increase the cost of production. Currently, both in the ferrous and non-ferrous metallurgy industries, two issues are relevant:

1) reducing the cost of production;

2) quality indicators of coke.

Indicators needed to assess the quality of coke for non-ferrous metallurgy include the moisture content, ash, sulfur, metal impurities, true density, particle size distribution and electrical resistance, reactivity, calorific value.

The requirements imposed on the quality of coke used in non-ferrous metallurgy, in particular, on the sulfur content of coke, are diametrically opposite in relation to the blast furnace coke. In the production of blast furnace coke, the sulfur content in the coke is a rejection indicator and, accordingly, cokes with sulfur content above 1.0-1.2% are automatically excluded from the raw material base of the blast furnace process. For the blast-furnace coke, as indicated above, the high sulfur content is negative, and for the coke used in non-ferrous metallurgy, the high sulfur content is a positive thing. In today's conditions, technological personnel of coke plants need to be able to quickly reorganize and organize technological work so that the quality of coke strictly complies with the requirements of GOST standards or technical conditions, as well as the requirements of specifications for supply contracts agreed with each consumer plant.

In the production of nickel matte, the loss of nickel with slag is achieved when smelting ore-oil-coke briquettes and an increased sulfur content in the matte, which is explained by a more complete process of reduction and sulfidation of iron and nickel oxides in the briquette due to the increased reactivity of petroleum coke. Nickel goes to matte in the form of sulfide and pure metal due to the interaction with sulfur. Oxides of iron and other metals pass into the slag.

The proposed method due to the use of petroleum coke with different volatile matter, with a sulfur content of 1.1 to 6%, in the charge for the production of coke, the sulfur content in the finished coke increases almost five times compared to metallurgical coke, which significantly

- 2 031479 increases the efficiency of the use of this coke in the production of nickel matte.

Changes in the quality of coke can be achieved by changing the composition of the charge both in terms of the ratio of additives and grades of coal.

According to the invention, petroleum cokes with different volatile matter yield are mixed in a predetermined proportion, and the proportion of petroleum coke with volatile matter in the range from 7 to 13.9% is not more than 40% of the total charge, i.e. The quality characteristics of the raw materials and, as a result, the finished coke are clearly defined.

Volatile substances in petroleum coke are under-coked, i.e. not yet converted to the carboid state, the remnants of raw materials. When heated, they become liquid. The more volatile substances in petroleum coke, the greater the content of non-coked hydrocarbons in it, which increase its thermoplastic properties, such as sintering and the temperature range of the plastic state, which are important indicators in the production of coke.

Thus, by specifying signs in the formula for petroleum cokes with different volatile matter in the range from 7 to 13.9%, not more than 40% of the total charge, the inventors set the basis for calculating the charge by the technologist with a clear quality limit of 40%. The upper limit of petroleum coke provides the maximum available sulfur content. For the production of nickel matte, the minimum value of sulfur in coke is no less than 2. Therefore, the lower limit of the content of petroleum coke (sulfur-containing) is calculated. It uses raw materials with different elemental composition, available.

Oil cokes in the formula are limited by the indicators of volatile substances, the upper quantitative limit of not more than 40%. Those. The upper limit of petroleum coke provides the maximum available sulfur content. The lower limit of the content of petroleum coke is determined by calculation.

The presented method involves the dosing of raw materials for coking, while setting the proportion of the mixture of different grades of petroleum coke by volatile substances, in order to improve the physicochemical properties of coke, to ensure its effective use in the production of nickel matte. At the same time, the use of petroleum coke with a yield of volatile substances from 7 to 13.9% is limited, and their amount is not more than 40% of the total charge, and the share of each brand in the mixture is adjusted depending on the sintering index of the charge (mixture of components) by the Sapozhnikov method , the thickness of the plastic layer is U mm, either in terms of sintering by the Horn method, or by the free swelling index, i.e. calculated.

The text indicates the plastometric method of Sapozhnikov. It is considered that the greater the thickness of the plastic layer, the greater the sintering capacity of this coal. This method allows us to estimate not only the sintering of this coal, but also to select the charge for coking. The mixture is calculated.

In this case, it is assumed to vary the capabilities of the resource base. For example, the use of different brands of petroleum electrode coke, including it in the composition of the initial mixture of petroleum coke. Bulk mixture (mixture) is controlled by composition to ensure sintering and a given level of volatile substances by sampling and conducting the necessary analyzes. The resulting mixture in fact must have technical parameters, within the limits of the dosage error of the components, both in terms of the yield of volatiles and in terms of sintering, comparable to the calculated, calculated by calculation based on the source data, to obtain the necessary coke physico-chemical properties.

There is a close relationship between the strength of coke and the optimal sintering level of the charge. Coke, obtained from a mixture having high sintering properties, has a low level of coke strength.

For the production of nickel matte, as indicated above, such characteristics of the finished coke as the moisture content, ash, sulfur, true density, particle size distribution and electrical resistance, reactivity, calorific value are of importance.

The reactivity of coke with respect to air blast in a shaft furnace, in turn, is predetermined by the adsorption capacity of coke and catalytic impurities, such as sulfur, sodium and vanadium. The adsorption capacity is determined by the presence and nature of free valences, the structure of the electron shells of surface atoms. Oil sulfur cokes have a greater adsorption capacity than low-sulfur. And their participation in the mixture of the mixture determines the presence of certain properties of the finished coke. Consequently, coke, manufactured by the proposed technology, is an active reducing agent, which is essential for its use in non-ferrous metallurgy.

Sodium increases the reactivity of coke in carbon dioxide, vanadium catalyzes the oxidation reaction with air, sulfur contributes to a more complete process of reduction and sulphidation of iron and nickel oxides.

Obtained by the claimed method coke meets the requirements for the production of nickel matte, as shown in the table. one.

- 3 031479

Table 1

Name indicator The values of the indicator in the resulting coke Required value for nickel matte production №1 №2 Moisture content in% 4.9 4.0 5.0-6.0 Ash content in% 8.1 8.4 6.0-8.0 Sulfur content in% 2.02 2.01 2.0-5.0 Volatile matter at% 0.4 0.4 1.2 Mechanical strength M25% 84.5 84.3 82.0 Abrasion M10% 9.6 9.0 10.0-11.0 Lump content less than 25mm% 4.4 4.3 4.5

For comparison, the sulfur content in the blast furnace coke is 0.6%, the ash content is 12.5%.

The moisture content in the finished coke (as can be seen from Table 1) complies with the requirements for coke for mine smelting. In the production of nickel matte, the required moisture content is achieved by selecting the optimal mode for the wet extinguishing method.

The content of volatile substances in coke characterizes the level of carbon content, which affects the calorific value.

Oil electrode coke is much cheaper than analogs. Thus, the use of coke, obtained by the proposed technology, will allow the use of various brands of electrode coke and at the same time increase the efficiency of production of nickel matte. The use of grades of petroleum electrode coke for this purpose is unknown in the prior art, but the possibility of its use is confirmed by the authors of the present invention in practice. The symptom is in causal connection with the stated technical result and is significant.

In the proposed method of producing coke from a mixture containing a mixture of coal from different technological groups, as well as petroleum coke with different volatile substances, while proportionally decreasing weakly caking or non-coking coal or petroleum coking additive, all components of the mixture are crushed together. As stated above, petroleum electrode coke is allowed. And in this case, the share of participation of petroleum electrode coke (as indicated above) is determined by the optimal sintering index. The optimal level of sintering according to the Sapozhnikov method, the thickness of the plastic layer is U = 13.5-15.0 mm, the index of free swelling SI 3.5-5.5 units, the sintering method according to the Horn method is 50-60 units. The share of participation of petroleum electrode cokes with different volatile matter yields is selected, taking into account the optimal sintering levels of the charge indicated above. At the stage of formation of a mixture of petroleum coke (in a given proportion), the physico-chemical properties of coke are set (planned) to ensure its effective use in the production of nickel matte.

In market conditions, the question of determining the composition of the charge from the available raw materials plays an unimportant role. Those. batch parameters were set (Y = 13.5-15.0; SI free swelling index 3.55.5 units; sintering according to the Horn method 50-60 units), interconnected indicators; a change in one indicator causes a change in others. In the presence of a specific database on the quality characteristics of the available coal, the process engineer has the opportunity to determine the composition of the charge, knowing its parameters and knowing the elemental composition of the coal.

This reduces the time of the technological process due to the simultaneous grinding of the entire mixture. Reducing the proportion of coals weakly caking and non-caking reduces the cost and reduces the cost of production. The symptom is in causal connection with the stated technical result.

Petroleum coke is the final solid product of highly condensed structures of deep transformations of petroleum hydrocarbons and their hetero derivatives during thermal degradation. Considering the fact that in petroleum coke, with different volatile matter, the content of the mineral part, namely ash, is insignificant and amounts to 0.3-0.6%, and the share of these products in the charge is about 70%, and therefore not A high level of grinding of the charge is required, which is necessary in the production of blast-furnace coke, where the participation share of petroleum electrode coke can be from 1 to 7%. In addition, the crushing of all components of the mixture at the same time allows to reduce the time, while obtaining a homogeneous composition.

As can be seen from the table. 1, the reduction of the mineral part, namely the ash in the resulting coke is practically

- 4 031479 2 times than in the metallurgical, which has a positive effect on the calorific value of coke due to the increase in the proportion of carbon content and due to this increase in calorific value.

In addition, by reducing the ash content of coke, the efficiency of the fusion increases. Increases the efficiency of using finished coke in the production of nickel matte. The sign of the formula is in a causal relationship with the stated technical result and is significant.

The grinding of the charge in this method of coke production is 68-72%. This simplifies the process of preparing the charge for coking, reduces the cost of coke production, saves electricity. At the same time, when using, for example, petroleum electrode coke, instead of weakly caking or non-caking coal, or petroleum coking additive, there is a decrease in the yield of volatile substances of the charge, which leads to an increase in the yield of gross coke.

Petroleum coke can be dosed in specified proportions using metering devices, or when laying the pile of petroleum coking additive, given that these products are made of the same raw material, which also greatly simplifies the process of preparation of the charge, optimizes the process.

Mixing different brands of petroleum coke in a given proportion and controlling the proportion of petroleum coke with a volatile content in the range from 7 to 13.9% not more than 40%, at the same time we reduce the price of products and control the quality of the coke to be used in the production of nickel matte. The mixture of petroleum coke obtained by the method specified in the formula in the coking process due to the high temperature range of plasticity, the optimum level of sintering, improves the strength properties of coke in terms of M25, M40, M10.

Practical work in the conditions of industrial coking on the coke battery No. 2bis of JSC Gubakhinsky Coke showed that the quality of coke obtained from the charge, according to the proposed method, meets the requirements imposed on the quality of coke, when producing nickel matte in shaft furnaces, both in sulfur content and and ash content, mechanical strength of M25 and M10, reactivity.

The mechanical strength of the M25 and the abradability of the M10 in the baseline and experimental period are practically at the same level, the quality of the coke in terms of mechanical strength has not deteriorated. The resulting high-sulfur and low-ash coke works very well in shaft furnaces in the production of nickel matte. As practice has shown, the yield of nickel increases by 0.5-0.7%.

In the formula, specifying oil cokes with different volatile matter in the range from 7 to 13.9%, not more than 40% of the total charge, the inventors set the basis for calculating the charge by the technologist with a clear quality limit of up to 40%. It uses raw materials with different elemental composition, available. Indicating in the description of the invention, the parameters of the charge (plastic layer thickness 13.5-15; free swelling index 3.5-5.5; sintering according to the Horn method 50-60 units), quality characteristics of electrode coke (elemental composition) and indicators of the finished coke, the authors actually give all the necessary indicators for the calculation of the charge by the technologist, in this case an expert in this field of technology. Thus, the proportion is calculated based on the raw materials that are available.

Industrial applicability of the proposed method is confirmed in practice, the initial data for the calculation of the charge are given, the calculation methods are indicated.

Since the method of nickel matte production involves the reduction sulphidizing shaft smelting of oxidized nickel ores in the presence of a sulphidizing agent (pyrite, pyrite, gypsum), a fluxing agent (limestone) and metallurgical coke, which is both a reducing agent and a fuel, while its reactivity is very important and calorific value, which depends on the moisture content and coke ash content.

High-sulfur coke produced by the proposed method cannot be used in blast furnace smelting, but in the production of nickel matte it reduces the participation of the sulfiding agent (pyrite, pyrite, gypsum, or elemental sulfur), and also reduces coke consumption. Metallurgical coke has a high ash content of 11.5-12.5%, which leads to an increase in the amount of slag and a decrease in the specific ore fusion, the specific productivity of the shaft furnace, which is related to the cross-sectional area in the lance plane, decreases.

The ash content in the coke produced by the proposed method is almost two times lower than in the metallurgical, so when using such coke, the amount of slag generated from the ash content of coke in the shaft furnace will be formed at least two times less, which will increase the productivity of the mine furnace and increase the melting of ore. Increases the efficiency of nickel matte production.

Reducing coke consumption, reducing the melting time is caused precisely by the improvement of the physicochemical properties of coke: calorific value, increased density, reactivity.

Oil electrode coke (as a variant of petroleum coke) perfectly replaces low-creeping

- 5 031479 or non-coking coal, or petroleum coking additive, and works as an emaciated additive with a high carbon content. The quality of the oil electrode coke used in this method of producing coke is given in table. 2

table 2

Moisture Content Wr% Sulfur content Sd% The output of volatile substances Vdaf% Caking by the Horn method Index swelling Si unit 9.4 4.52 9-13,9 10-18 1/2

As practice has shown, the proposed method allows to reduce the consumption of coal or petroleum coking additive up to 40%, while maintaining the quality of coke, while simplifying the process of producing coke. The industrial applicability of the produced coke is confirmed by the enclosed quality certificates.

Experimental batches of coke obtained by the proposed method were implemented for the needs of non-ferrous metallurgy and showed a high effect in the production of nickel matte. Practically confirmed the industrial applicability of the proposed method.

Distinctive features of the claims in the aggregate: petroleum cokes with different volatile substances are mixed in a given proportion and the proportion of petroleum cokes with volatile matter in the range from 7 to 13.9% not more than 40% of the total charge, use petroleum coke with sulfur content from 1.1 to 6% and ash content from 0.1 to 2%, with a corresponding decrease in slightly caking or non-caking coal, all components of the charge are crushed together and then the mixture is fed to the layer coking is not known from the prior art and their effect is not known on the technical result proposed by the applicants and involve the use of a wide range of raw materials, at the same time varying both by the quantitative ratio of the bookmark and the formation of the granular mixture, and the cost of production.

As indicated above, the most common technical solution was, for example, the use of high-sulfur petroleum coke fines (for example, AS No. 254471) exclusively for expanding the raw material base, etc. The authors of the present invention are not aware of technical solutions in this area, containing all the distinctive features of the claims, which provided for savings on production by optimizing the process at the same time coke production and the use of coke in nonferrous metallurgy. The problem was not fully resolved. The proposed technical result is confirmed in practice. Using the proposed method will reduce costs and improve the technological process of production, resulting in savings in the production of coke and improve the technological performance of nickel output in non-ferrous metallurgy. The proposed invention, according to the authors, meets the requirements of current legislation on inventive step.

Efficiency, combined with the quality of the coke produced, and as a result, obtaining a higher nickel yield in difficult competitive conditions of operation of metallurgical enterprises associated with sanctions against the Russian Federation, play a positive role.

The proposed method is technological, efficient, economical, industrially applicable and in demand.

Claims (1)

CLAIM The method of producing coke from the charge, including coking a mixture of coal and petroleum coke with a fraction of less than 25 mm, characterized in that petroleum coke with a yield of volatile substances in the range from 7 to 13.9% is mixed with coal, with the proportion of petroleum coke being not more than 40 % of the total volume of the charge, and petroleum coke with a sulfur content of 1.1 to 6% and ash content of 0.1 to 2% is used, then all the components of the charge are crushed together and the mixture is fed to layer coking in coke oven batteries.