UA145699U - FUEL MIXTURE FOR AGGLOMERATION OF METAL ORE - Google Patents

Abstract

The fuel mixture for agglomeration of metal ores contains as fuel a non-renewable carbon-containing component and an organic renewable component. The organic renewable component is pyrolysis solid ligninocellulose biomass, in the following ratio,% wt .: organic renewable component - 1-95 non-renewable carbon-containing component - the rest.

Description

The useful model belongs to ferrous metallurgy, in particular, to the composition of the charge for agglomeration production.

The agglomeration process is widely used for the sintering of metal ores. Agglomeration of metal ores and concentrates consists in their flocculation by sintering, which occurs due to the burning of fuel in the previously flocculated material - the sinter charge.

The resulting agglomerate is used for iron smelting in a blast furnace, ferroalloy smelting in electric furnaces, converter steel smelting or in direct iron recovery processes.

To obtain agglomerate, it is necessary to use fuel, which during combustion provides heat for the flow of chemical reactions, and also acts as a metal reducer. Fuel for agglomeration must have the following main qualitative and technological characteristics: minimum possible ash content and moisture; limited output of volatile substances (up to 15 95); limited content of the fraction I 3 mm (no more than 5-10 95) for coke and anthracite; the minimum fraction content is 0.5 (0.63) mm; high reactivity » 1.5 ml/(gs) according to GOST 10089-89, non-volatile carbon content greater than 76 95, constancy of technological indicators of fuel.

A known fuel for agglomeration of metal ores is hard coal coke less than 10 mm in size (coke fines), which is a screening after sorting the coke obtained as a result of the coking process of hard coal (Efimenko H.G., Himmelfarb A.A. , V. E. Levchenko

Iron metallurgy. - K.: Vyscha Shk. Main publishing house, 1988. - 351 p.|. Anthracite is also widely used as a fuel. In addition, other carbon-containing materials can be used.

The use of anthracite or coal coke during sintering leads to significant emissions of harmful substances and greenhouse gases. In addition, taking into account the constant increase in the cost of coal and coke, their multi-tonnage use causes the deterioration of the economic performance of metallurgical enterprises. This encourages the development and use of alternative sources of metallurgical fuel, which should ensure improvement of the technical and economic performance of metallurgical enterprises, be available and contribute to the reduction of emissions of harmful substances into the environment.

Biomass has significant renewable carbon potential and CO52 neutrality.

The use of original biomass as a solid fuel has a number of disadvantages.

Disadvantages include low bulk density, high humidity and release of volatile substances, high oxygen content, presence of alkaline earth metals, relatively low carbon content and, as a result, relatively low heat of combustion.

The mixture for the production of coke is the closest to the declared one (Patent for a useful model

OA 81564). IPC (2013.01) STOV 57/00. A mixture for the production of coke. Captain E.V., Koverya A.

S. // 10.07.2013, Bulletin Me 13. - From p.), which may contain coal of various technological grades and an organic component. As an organic component, wood of various species is used in the form of pellets and briquettes, or waste from agricultural production, for example, processing of sunflower, straw, walnut, corn, rice and buckwheat husks, tree leaves, sunflower husks, etc., up to 10 mm in size , as well as in the form of granules and briquettes, or pulp industry waste with a grain size of up to 10 mm, as well as in the form of granules and briquettes, or peat with a grain size of up to 10 mm, as well as in the form of granules and briquettes, or a mixture of the above components, while the content they do not exceed 50 95 of the total mass of the mixture. However, the mixture can only be used to obtain fuel and reducing agents for further use, including in the agglomeration of metal ores.

With the help of additives of organic substances, it is possible to influence the quality of coke and improve its technological characteristics for consumers. In addition, the cost of coke obtained using many of the declared additives will be lower than the cost of obtaining the corresponding grades of coal coke.

The disadvantage of using the mixture proposed in the prototype is the production of biocoke, the structure of which simultaneously contains particles of pyrolyzed coal (coke) and biomass (charcoal), i.e. there is no possibility to ensure obtaining a homogeneous structure of the product and the impossibility of separate use of biofuel in the mixture and, as a result, achieving necessary technological characteristics of the agglomeration process.

The basis of the useful model is the task of improving the well-known mixture for agglomeration of metal ores, in which, due to the introduction of new components and their ratio, it is possible to increase the bulk density at the required humidity, reduce the yield of volatile substances, reduce the content of oxygen, alkaline earth metals, significantly increase the carbon content, and as a result, the heat of fuel combustion, and due to this, increasing the productivity of the sintering process, improving the properties of the obtained agglomerate along with reducing 60 harmful emissions during the process.

The task is solved by the fact that in the composition of the fuel mixture for the sintering of metal ores, which contains a non-renewable carbon-containing component and a renewable organic component, the organic renewable component is pyrolysis solid lignin-cellulosic biomass, with the following ratio: organic renewable component - 1-95 95 mass; non-renewable carbon-containing component - the rest.

The declared useful model - the fuel mixture is formed as follows. Pre-pyrolyzed solid lignocellulosic biomass is mixed with a non-renewable carbon-containing component depending on the given ratio. Any lignocellulosic biomass can be used to obtain pyrolysis solid biomass. As an example, when using wood and sunflower seed husks in the form of granules and walnut shells, the pyrolysis temperature was: for wood - 400, 600, 800 and 1000 "C, for sunflower seed husks and walnut shells - 600 "C. Table 1 shows the technical and elemental analyzes of the obtained pyrolysis solid biomass.

Table 1

Technical and elemental analyzes of fuels, 90 (temperature Moisture, Ash content, total organic matter | Hydrogen, | Carbon, Nitrogen. M Non-volatile a a z si a a a ' pyrolysis, -C) MI A ma sulfur, bi N (o; carbon fraction "connection of conifers".

Wood pellets! 36 75 36.35 | tracks 4A 60.37 | 059 | 5byB 400 C)

Wood pellets! 26 12.3 13.56 | traces 24 715 0.61 74.14 600 s)

Wood pellets! 2 14.9 9.98 |traces 1.01 7916 | 062) 7542 800 s)

Wood pellets 24 14.3 7.76 | traces 0.77 80.84 | 043 | 77.94 1000 C)

Hull seeds 2.6 73.0 013 5.88 49.51 1.56 24 4 sunflower

Sunflower granules 47 11.85 229 | v95B | 128 | 8015 husk 600 s)

Shellfish 72 | 093 | 756 | 01 | 65 | 564 | 04 | Ha

Nutshell 6 3.6 10.04. | traces 297 | 88.74 035 8636 600 s)

As can be seen from Table 1, the original biomass was characterized by a high content of volatile substances, low ash content, very low sulfur content, low carbon content, high hydrogen content and low value of non-volatile carbon.

As a result of pyrolysis, the yield of volatile substances in the obtained solid residue decreases, the ash content increases, the carbon content increases significantly, and hydrogen decreases, sulfur is almost absent.

After the preparation of the fuel mixture, a sintering charge is made, which, in addition to fuel, includes iron ore, iron ore concentrate, ordinary limestone, lime and slag.

The chemical composition of charge materials, except for fuels, is given in Table 2. Table C shows the composition of the sintering charge, which corresponds to the industrial one.

Table 2

Chemical composition of charge materials, oxides, solder, concentrate

Ordinary limestone 028 | - | 040 | 15 | 056 | 485) 092 | 4356| - (Total | 1266 - |1809| 18 |2661|868|140| - | -

Table C

Composition of agglomeration charge

Fuel (coke fines, pyrolysis biomass) food/-/:/ g /Ї77777711116ссСсшС у

The agglomerate was obtained as follows: the charge materials were weighed, mixed, moistened, re-mixed and flocculated in a drum-type flocculator. The consumption of water for each sintering when using coke fines was 7 95, taking into account which was corrected in other sinterings taking into account the moisture content of the fuel. The lumped charge was loaded into a bowl with a grate, on which a bed of agglomerate with a fraction of 10-5 mm (the so-called return) was previously laid. Next, the initial discharge under the grate was set to a level of 500 mm. water century, and for 60 seconds the charge was ignited to start the sintering process, the ignition temperature was approximately 1250 "C. During sintering, the pressure drop under the grate was recorded, which depended on the gas permeability of the sintering layer. Sintering was completed when the gas temperature, that are leaving, reached a maximum and began to decrease.

After the sintering process was completed, the finished agglomerate was studied.

Its yield, impact strength indicators, sintering speed and specific productivity of the process were calculated.

First, tests were performed with a change in the amount of pyrolyzed biofuel in the fuel mixture. The percentage of biofuel in the mixture was 25, 50, 75 and 95 95, respectively, non-renewable carbon-containing component (coke fines) - the rest. Using different types of pyrolysis biomass for tests, it was established that the acceptable amount of biofuel without reducing the specific productivity of the process and the quality of the agglomerate is 25 95.

Further studies of the influence of different types of biofuels on the agglomeration process and the quality of the agglomerate were carried out with the amount of the renewable component in the fuel mixture 25 95. Table 4 summarizes the results of the agglomeration process and the quality parameters of the obtained agglomerates in comparison with the reference values obtained when using coke fraction as fuel "link"

Table 4

Results of the agglomeration process and quality parameters of the obtained agglomerates when using different types of pyrolysis fuel

Type of fuel | Output Maximum | Speed Specific strength temperature of it. : pyrolysis agglomerate, "C agglomerate | pressure drop, sintering, productivity, | 4 impact, 95 (- (4-10 mm), 95 kPa mm/min. t/m2 h. 5

mm)

Coke fines 2.0 32.5 1.83 93.5 1100 C)

Sunflower husk granules 2.5 34.5 1.97 92.0 seeds (600 C)

The shell of a nut pe ti vo | 351 5 51

Wood pellets 66.5 3.0 34.5 1.87 88.0 400 C)

Wood pellets 71.5 3.0 40.2 2.44 600

Wood pellets 73.0 4.0 36.8 2.19 94.5 800 s)

Wood pellets 68.25 2.0 34.0 1.95 91.0 1000 C)

As can be seen from Table 4, the yield of a suitable agglomerate (i-10 mm) can be obtained at the same level as the basic one, when using sunflower seed husk pellets, wood pellets and walnut shells pyrolyzed up to 600 "C, as well as when wood pellets are pyrolyzed up to 800 "C .

The addition of pyrolyzed biofuels to the sintering charge leads to an improvement in the gas permeability of the sintering layer. Particles of biomaterials are located between the granules of the charge evenly and increase the open porosity of the layer. The final pressure drop for the finished agglomerate layer also decreases, which indicates an increase in the open porosity of the agglomerate when using biomaterials.

When pyrolyzed biomass is used, a higher vertical sintering rate is observed than when only coke fines are used. The specific productivity corresponds to the change in the yield of agglomerate (-- 10 mm) and the sintering speed, so it increases according to the change in these indicators.

The highest impact strength of the agglomerate was achieved when using wood pellets pyrolyzed to 800 "С. Within the margin of error, relative to the reference value, there are also properties of the agglomerate obtained using pellets from sunflower husks and walnut shells, previously pyrolyzed to 600 "С. Therefore, in order to achieve the impact strength values of the agglomerate, depending on the requirements of consumers, the final temperature of biomass pyrolysis should change.

Thus, the test results show that the use of pyrolyzed biomass in the fuel mixture for iron ore agglomeration can improve the characteristics of the sintering process and the quality of the agglomerate. At the same time, the improvement effect can be achieved by using different types of biofuels with different levels of carbonization. In addition, the use of biofuels contributes to the reduction of emissions of 502, MOH and volatile organic compounds, including dioxins and polycyclic aromatic hydrocarbons due to the almost complete absence of sulfur in pyrolysis biomass and low nitrogen content compared to non-renewable fuels.

The positive effect achieved by the implementation of the declared useful model is the expansion of the raw material base for obtaining agglomerates, increasing the productivity of the sintering process, improving the properties of the agglomerate: yield and impact strength. Also, another mixture of organic components makes it possible to reduce the cost of the charge, dispose of wood processing, agricultural and pulp industry waste, reduce harmful emissions into the atmosphere, which significantly contributes to the solution of urgent environmental protection issues. Also, the use of granules has advantages from the point of view of raw material transportation, due to higher bulk density, as well as ease of addition to the charge.

Thus, the mixture with the participation of pyrolyzed biomass, for obtaining metal agglomerate, will contribute to the improvement of the technical and economic indicators of the work of sintering workshops and increase the profitability of the production of metallurgical products.

Claims (1)

USEFUL MODEL FORMULA A mixture of fuels for the sintering of metal ores, containing as a fuel a non-renewable carbon-containing component and an organic renewable component, which is characterized by the fact that the organic renewable component is pyrolysis solid lignin-cellulosic biomass, with the following ratio, 9% by weight: organic renewable component - 1-95 non-renewable carbon-containing component - the rest.