EA038571B1 - Method for producing petroleum-coal tar pitch binder - Google Patents

Abstract

A method comprises mixing coal tar and a product of oil refining in a pre-determined ratio; thermally treating the mixture produced in the liquid phase while separating distillate fractions from undistillable distillation residue in the form of a low-temperature pitch; and oxidizing the undistillable distillation residue with air, thereby producing a petroleum-coal tar pitch binder. The mass ratio of coal tar to the product of oil refining at the mixing step ranges from 49:51 to 25:75 wt.%; the thermal treatment of the mixture produced is conducted until a distillation residue with a softening temperature of 35°C or above is obtained. The resulting petroleum-coal tar pitch binder is used for making anode paste for aluminium electrolysis cells, items and materials for the metallurgical industry and electrode manufacturing. The method makes it possible to expand a raw material range for the production of pitch binders for electrodes with a reduced benzo[a]pyrene content.

Description

Technology area

The invention relates to the field of metallurgy, in particular to methods of producing and preparing electrode pitch intended for the production of anode mass, coal and graphite products, structural carbon-graphite materials, and can be used in the coke-chemical, oil refining, electrode industries.

State of the art

The main type of binder for the production of the anode mass is coal tar pitch, the non-distillable residue of the distillation of coal tar.

The most widespread in industry for the production of anode mass was obtained by grade B coal electrode pitch according to GOST 10200-83, the quality indicators of which are given in table. 1.

Table 1

Indicator name Electrode pitch, grade B in accordance with GOST 10200-83 1. Softening temperature according to KiS (according to Mettler), ° C 85-90 2. Mass fraction of substances insoluble in toluene (os-fraction),% not less than 31 3. Mass fraction of substances insoluble in quinoline (os 1-fraction),% no more than 12 4. The output of volatile substances,% 53-57 5. Coke residue,% - 6. Mass fraction of benzo [a] pyrene,% -

Coal tar pitch is a by-product of the process of obtaining metallurgical coke from coal; the scale of its production decreases with an increase in the need for a binder pitch from the electrode industry and the production of aluminum by the electrolytic method, in particular.

Petroleum pitches, which are obtained by processing various petroleum residues, can be used to a limited extent in the manufacture of electrode products, mainly in the form of impregnating and low-temperature pitches. A known method of producing petroleum pitch by vacuum distillation of resin from thermal cracking of petroleum products (patent RU 2288251, 26.11.2002). The resulting pitch has a softening point of 133 ° C, a viscosity of 11818 mPa-s at 180 ° C, and a coke residue of 53.7%. High viscosity and softening temperature do not allow the use of petroleum pitch as a binder for the production of anode mass and anodes of aluminum electrolyzers.

Known methods for producing petroleum pitches by various methods of heat treatment of heavy pyrolysis resin or its fractions (patents RU 2645524, 06/21/2017; RU 2659262, 09/14/2017; RU 2663148, 09/14/2017; RU 2647735, 06/01/2017; RU 94028240, 27.07. 1994). The resulting pitches, depending on the technology used, have a wide range of softening temperatures from 70 to 155 ° C in the absence of α 1-fraction (substances insoluble in quinoline) in the pitch and a low content of α-fraction (substances insoluble in toluene) 10-18 %. The low content of the α-fraction and the absence of the α1 fraction, as well as the low yield of coke residue, do not allow the use of petroleum pitch as a binder for the production of anode mass and anodes of aluminum electrolyzers.

A known method of producing petroleum pitch by joint thermal processing of thermal cracked petroleum products and heavy pyrolysis resin (application RU 95100115, 01/05/1995). The resulting oil pitches have a low content of α 1-fraction up to 1.8% and an increased yield of volatile substances of 6270%, which does not allow the use of such pitch instead of grade B coal tar pitch according to GOST 10200 with the required quality characteristics indicated in table. 1.

There is evidence that petroleum pitch can be used as a binder electrode pitch, having previously mixed it in a certain proportion with coal tar pitch. For example, in US patent 5746906A, 08.10.1995, a method is proposed for producing a hybrid petroleum-coal pitch with a softening point in the range of 107-114 ° C and a reduced content of polyaromatic hydrocarbons (PAHs) by mixing coal tar pitch with an increased softening point and petroleum pitch with a reduced softening point in a ratio of 60:40. The resulting mixed binder pitch has a softening temperature of 110-112 ° C, the content of a1-fraction is 10-12%, which makes it suitable for the manufacture of anode mass of aluminum Soderberg electrolyzers and for prebaked anodes. The described method of producing a binder for petroleum-coal tar pitch is applicable if industrial volumes of petroleum pitch are available on the market.

According to another known method (patent RU 2080418, 05/27/1997) it is proposed to use a homogeneous mixture as a carbon-containing binder in the production of anode mass, obtained by mixing coal tar pitch with petroleum pitch at a ratio of 19: 1-2: 1. Mixing of coal tar pitch with petroleum is carried out by pumping the mixture from the lower zone of the vessel to the upper zone at the rate of 1-3 times exchange of the total flow in a turbulent mode.

The disadvantage of methods for producing petroleum-coal tar pitch, using a mixture of petroleum-1038571 and coal tar, is the need for industrial production of petroleum pitch.

In addition, carrying out the stage of mixing coal and petroleum pitches requires capital and energy costs associated with the creation of an installation including heated tanks for pitches and equipment for mixing.

There is a known method of producing petroleum-coal tar pitch by distillation of resin followed by oxidation (patent RU 2569355, 06.06.2014), in which the resin is used as a product of joint coking of a mixture of coal charge with petroleum semi-coke with a volatile matter yield of 14 to 25% with a content of petroleum semi-coke in coking mixtures of 10-50 wt.%. The method allows to expand the raw material base for the production of oil-coal tar pitch, to simplify the method of its production.

Known methods of joint processing of coal tar or coal tar pitch with heavy oil residues. For example, in patent RU 2517502, 06.12.2012, processing is carried out in the field of hydropercussion-cavitation impulses and when air is supplied. The resulting binder petroleum-coal pitch is characterized by a reduced content of benzo [a] pyrene to 5.2 mg / g of pitch and coke residue of 49.9% at a feedstock ratio of 50:50.

In the patent RU 2013416, 07.19.1992, 1035% of distillate cracking residues or pyrolysis resin is added to the coal tar before distillation. The resulting pitch has a softening point of up to 81 ° C, an α-fraction content of up to 25% and a benzo [a] pyrene content of 1.3-1.8%.

The closest to the proposed invention in terms of the technical essence and the achieved result is a method for producing a binder for the manufacture of carbon materials (patent RU 2582411, 11.24.2014). According to the known invention, the binder is obtained by thermal treatment of a mixture of coal tar and liquid refined product in a ratio of 85:15 to 50:50 wt.% At 410-430 ° C, followed by oxidation of the non-distillable distillation residue with air at 325-360 ° C and with air supply at the rate of 20-70 dm ³ / kg pitch. The disadvantage of this method is the limitation of the proportion of liquid oil in the mixture to 50 wt.%. This limitation is due to the fact that with an increase in the proportion of liquid refined product in the mixture of more than 50 wt%, the resulting binder pitch has low values of substances insoluble in toluene and quinoline (α- and a ₁ -fractions), which does not allow the use of such pitch in the manufacture of anode masses and carbon products. In addition, this method does not allow to obtain electrode pitch that meets the requirements for the mass fraction of substances insoluble in quinoline (a1-fraction), not more than 12%, when using as a raw material coal tar with a high content of a1-fraction.

Disclosure of invention

The objective of the claimed invention is to obtain a petroleum-coal binder pitch with a reduced content of benzo [a] pyrene and an increased share of petroleum products, as a cheaper and more affordable raw material, while maintaining other quality indicators at a level that allows the use of a petroleum-coal binder pitch for the manufacture of anode masses, coal and graphite electrodes, structural carbon materials.

The task is achieved by the fact that in a method for producing a petroleum-coal binder pitch, including mixing coal tar and a refined oil product in a given ratio, heat treatment of the resulting mixture in the liquid phase with the separation of distillate fractions and non-distillation residue in the form of low-temperature pitch, oxidation of the residue by distillation with non-distillation oil-and-coal binder pitch, according to the claimed invention, the ratio of coal tar and oil refined product when mixed is 49: 51-25: 75 wt.%, heat treatment of the resulting mixture is carried out to obtain a distillation residue with a softening temperature of at least 35 ° C in continuous or batch modes, and the air consumption during the oxidation of low-temperature pitch is 30-120 dm ³ / kg pitch.

It is preferable to use a liquid oil product with a high content of aromatic compounds, having a density at 20 ° C not less than 1020 kg / m ³ , a viscosity at 100 ° C not more than 20 cSt; coking capacity not less than 5%; distillation of the fraction boiling up to 300 ° C, no more than 5%; it is optimal that the density of coal tar is 1190-1225 kg / m ³ , the content of substances insoluble in quinoline is not less than 4 wt.%; heat treatment of the mixture is expediently carried out at a temperature of 400-440 ° C; the oxidation temperature of the low-temperature pitch is preferably 325-360 ° C; in order to improve the technology for obtaining a petroleum-coal binder pitch in a continuous mode, before oxidation, the non-distillable distillation residue having a softening point of less than 35 ° C is subjected to repeated heat treatment by returning it to the stage of mixing the coal tar and the oil refined product; When obtaining a petroleum-coal binder pitch in a batch mode, the heat treatment of the resulting mixture is preferably carried out for 1-4 hours until a non-distillable distillation residue is obtained, having a softening temperature of at least 35 ° C.

The proposed invention relates to the use of the above method for obtaining anode mass, carbon and graphite electrodes, structural carbon materials (products of the coke-chemical or oil refining industry) with a reduced content

- 2,038571 benzo [a] pyrene. The invention can be implemented at coke-chemical, oil refining or petrochemical plants. Obtained according to the claimed invention, petroleum-coal binder pitch can be used for the production of carbon products and materials at enterprises of the metallurgical and electrode industries.

The method allows to expand the raw material base for the production of petroleum-coal binder pitches with a reduced amount of benzo [a] pyrene and suitable for the manufacture of anode masses, carbon and graphite electrodes, structural carbon materials.

The resulting oil-coal binder pitch fully complies with the requirements of GOST 10200 for the quality of grade B pitch, the softening temperature of the oil-coal binder pitch is from 85 to 90 ° C, the content of substances insoluble in toluene is 32-39 wt%.

To obtain a petroleum-coal binder pitch according to the claimed invention, the heat treatment of the mixture can be carried out in batch or continuous modes.

The achievement of this task is facilitated by the use of a liquid refined product with a high content of aromatic compounds, having a density at 20 ° C not less than 1020 kg / m ³ , a viscosity at 100 ° C not more than 20 cSt; coking capacity not less than 5%; distillation of the fraction boiling up to 300 ° C, no more than 5%,

The achievement of this task is facilitated by the use of coal tar with a density of 1190-1225 kg / m ³ , the content of substances insoluble in quinoline, not less than 4 wt.%.

The achievement of this task is facilitated by the fact that the heat treatment of the mixture is carried out at a temperature of 400-440 ° C, the air consumption during the oxidation of the non-distillable distillation residue is 30-120 dm ³ / kg pitch, the temperature during the oxidation of the non-distillable distillation residue is 325360 ° C.

When obtaining a petroleum-coal binder pitch in a continuous mode, the achievement of the task is facilitated by the fact that before oxidation, the distillation residue is subjected to repeated heat treatment by returning it to the stage of mixing the coal tar and the refined product.

When obtaining a petroleum-coal binder pitch in a periodic mode, the achievement of the set task is facilitated by the fact that the heat treatment of the resulting mixture is carried out for 14 hours.

The study of the heat treatment of a mixture of coal tar and a petroleum product showed that when distilling mixtures of coal tar and a petroleum product at a ratio of 49:51 to 25:75 wt.% Under the temperature conditions of coal tar distillation, it is impossible to obtain a distillation residue (pitch) with the required softening temperature ( not less than 85 ° C for grade B according to GOST 10200-83 or within 80-90 ° C for petroleum-coal pitches obtained by mixing) and other quality indicators that meet the requirements for pitches for the production of anode mass. The use of a share of coal tar more than 49 wt.% And less than 25 wt.% Leads to the production of a petroleum-coal tar pitch that does not meet the requirements for a binder pitch.

To improve the characteristics of oil tar pitch after the stage of joint distillation of a mixture of coal tar and a refined product, it is proposed to subject the obtained non-distillable distillation residue (softening temperature within 35-70 ° C) to air oxidation. Co-distillation of resins is understood as mixing coal tar and oil refined product, heat treatment of the resulting mixture at elevated temperature in the liquid phase with separation of distillate fractions and non-distillable distillation residue.

Heat treatment (co-distillation) must be carried out until a non-distillable distillation residue with a softening point of at least 35 ° C is obtained, otherwise (when a non-distillable distillation residue is obtained with a softening point of less than 35 ° C) the air oxidation stage will not be sufficient to obtain a petroleum-coal binder pitch satisfying binder pitch requirements.

The proposed method makes it possible to obtain oil-coal-tar pitch with quality indicators close to those for coal-tar electrode pitch, low benzo [a] pyrene content and a higher proportion of oil refined product.

The specific values of the technological parameters depend on the characteristics of the coal tar used, the refined product, the composition of the mixture entering the distillation, the softening temperature of the distillation residue after the first stage, and the required parameters of the oil tar pitch.

The proposed method for producing petroleum-coal tar pitch can be carried out both in batch and in continuous mode at existing installations for processing coal tar and does not require the production of petroleum pitch and the creation of an installation for mixing pitches.

Carrying out the proposed process in a continuous mode is associated with obtaining, in the initial period of time, while along the technological line, which includes a tubular furnace for heating a mixture of coal tar and oil refined product, an evaporator for separating the distillate fraction of the resin from the non-distillable residue (pitch) and thermal holding of the pitch and cubes-reactors for the oxidation of pitch with air, a stable temperature regime will not be established, for soft pitches with softening temperatures less than 35 ° C. Therefore, such pitches from the evaporator are sent not to the oxidation stage, but to an intermediate tank, from where they can be dosed into the initial mixture and re-sent to the evaporation stage.

When carrying out the proposed process in a batch mode, the achievement of a softening temperature of at least 35 ° C of the non-distillable distillation residue (low-temperature pitch) is controlled by the time of heat treatment of the mixture.

Oil-and-coal binder pitch obtained by the proposed method is suitable for producing anode mass for aluminum electrolyzers with self-baking anode technology, as well as for the manufacture of pre-baked anodes of aluminum electrolyzers, carbon and graphite electrodes, carbon structural materials.

The main differences between the proposed invention and the prototype:

expanding the range of the ratio of coal tar and oil refined product (49: -5125: 75);

coal tar contains at least 4 wt.% of substances insoluble in quinoline;

the period of heat treatment in periodic mode was increased to 4 hours;

the temperature of the heat treatment of the mixture was increased to 440 ° C;

increased air consumption during oxidation to 120 dm ³ / kg pitch.

Implementation of the invention

The invention is illustrated by the following examples.

Example 1. Coal tar has a density at 20 ° C of 1222 kg / m ³ , the content of the α-fraction is 12%, the α1-fraction is 7.7%. Heavy catalytic cracking gas oil has a density at 20 ° C 1045 kg / m ³ , coking capacity 7%, viscosity at 100 ° C 16 cSt; the content of the α-fraction is 0.8%, and the _1- fraction is absent. A mixture of coal tar and catalytically cracked heavy gas oil in the ratio of coal tar: heavy gas oil 49:51 wt.% Is placed in a round-bottomed glass flask with a capacity of 0.5 dm ³ . The mixture is distilled at a final temperature of the liquid phase of 430 ° C with holding at this temperature for 2 hours. A low-temperature pitch with a softening point of 66 ° C is obtained.

Then the resulting low-temperature pitch is treated with air at 340 ° C for 5 hours at an air flow rate of 30 dm ³ per 1 kg of pitch. The yield of petroleum-coal binder pitch is 99.3% per load of low-temperature pitch.

Example 2. Mix coal tar and heavy gas oil catalytic cracking, as in example 1, in a ratio of 40:60 wt.%. The mixture is distilled at a final temperature of the liquid phase of 430 ° C and held for 2 hours, resulting in a low-temperature pitch with a softening point of 61 ° C.

Then the resulting low-temperature pitch is treated with air at 340 ° C for 5.5 hours, at an air flow rate of 40 dm ³ per 1 kg of pitch. The yield of petroleum-coal binder pitch is 99.5% per load of low-temperature pitch.

Example 3. Mix coal tar and heavy catalytic cracking gas oil, as in example 1, in a ratio of 25:75. The mixture is distilled at a final temperature of the liquid phase of 430 ° C and held for 2 hours, resulting in a low-temperature pitch with a softening temperature of 60 ° C.

Then the resulting pitch is treated with air at 340 ° C for 5 hours at an air flow rate of 40 dm ³ per 1 kg of pitch. The yield of petroleum-coal binder pitch was 99.5% per load.

Example 4. Coal tar has a density at 20 ° C 1192 kg / m ³ , the content of α-fraction 7.5%, a1-fraction 4.1%. Heavy gas oil catalytically cracked has a density at 20 ° C 1031 kg / m ³ , coking capacity 5%, viscosity at 100 ° C 14 cSt; the content of the α-fraction is 0.3%, the a1-fraction is absent. A mixture of coal tar and catalytic cracking heavy gas oil in the ratio of coal tar: heavy gas oil 30:70 wt.% is placed in a round-bottomed glass flask with a capacity of 0.5 dm ³ . The mixture is distilled at a final temperature of the liquid phase of 430 ° C with holding at this temperature for 2 hours. A low-temperature pitch with a softening temperature of 57 ° C is obtained.

Then the resulting low-temperature pitch is treated with air at 340 ° C for 5.5 hours, at an air flow rate of 36 dm ³ per 1 kg of pitch. The yield of petroleum-coal binder pitch is 96.2% per load of low-temperature pitch.

Example 5. Mix coal tar and heavy gas oil catalytic cracking, as in example 4, in a ratio of 25:75 wt.% And placed in a round-bottom glass flask with a capacity of 0.5 dm ³ . The mixture is distilled at a final temperature of the liquid phase of 440 ° C with holding at this temperature for 2 hours. A low-temperature pitch with a softening point of 41 ° C is obtained.

Then the resulting low-temperature pitch is treated with air at 340 ° C for 8 h at

- 4 038571 air consumption 70 dm ³ per 1 kg of pitch. The yield of petroleum-coal binder pitch is 98.6% per load of low-temperature pitch.

Example 6. Heavy pyrolysis resin has a density at 20 ° C 1051 kg / m ³ , coking capacity 11%, viscosity at 100 ° C 18 cSt; the content of the α-fraction is 0.6%, the αι-fraction is absent.

Coal tar is mixed, as in example 1, and a heavy pyrolysis resin in a ratio of 49:51 wt.% And the mixture is distilled at a final temperature of the liquid phase of 400 ° C with holding at this temperature for 4 hours. A low-temperature pitch with a softening point of 42 is obtained. ° C.

Then the resulting low-temperature pitch is treated with air at 340 ° C for 4 hours at an air flow rate of 80 dm ³ / kg pitch. The yield of petroleum-coal binder pitch is 91% per load of low-temperature pitch.

Example 7. Mix coal tar, as in example 1, and heavy pyrolysis resin, as in example 6, in a ratio of 25:75 wt.% And carry out the distillation of the mixture at a final temperature of the liquid phase of 440 ° C with holding at this temperature for 1 h. Get a low-temperature pitch with a softening point of 69 ° C.

Then the resulting low-temperature pitch is treated with air at 325 ° C for 2 hours at an air flow rate of 55 dm ³ / kg pitch. The yield of petroleum-coal binder pitch is 99.4% per load of low-temperature pitch.

Example 8 (prototype). Mix coal tar and catalytically cracked heavy gas oil as in example 1 in a ratio of 60:40. The mixture is distilled at a final temperature of the liquid phase of 430 ° C and held for 2 hours, resulting in a low-temperature pitch with a softening point of 70 ° C.

Then the resulting pitch is treated with air at 340 ° C for 4 hours at an air flow rate of 36 dm ³ per 1 kg of pitch. The yield of oxidized petroleum-coal tar pitch was 99.5% per charge.

The conditions for obtaining petroleum-coal tar pitch and its characteristics for examples 1-8 are given in table. 2, the mass fraction of ash in all samples of oil-coal sands does not exceed 0.3%.

Example 9 (in continuous mode). Coal tar has a density at 20 ° C 1209 kg / m ³ , the content of α-fraction 11%, αι-fraction 8%. A mixture of coal tar and heavy gas oil catalytically cracked as in example 1 in the ratio of coal tar: heavy gas oil 49:51 wt.% Was heated in a tube furnace to 436 ° C, then the heated resin mixture with a feed rate of 9 t / h was fed into the evaporator, where separation into pairs of distillate fractions, which entered the distillation column, and non-distillable distillation residue occurred. The softening point of the non-distillable distillation residue was 47 ° C. The non-distillation residue of the distillation was sent to a cube-reactor, where it was treated at 340 ° C at a flow rate of 70 dm ³ / kg of heated air pitch. The resulting oil-and-coal binder pitch had the properties indicated in table. 2, the mass fraction of ash 0.2%.

The non-distillation residue of the distillation, the softening point of which was less than 35 ° C, was sent to an intermediate vessel. After the process has entered the steady state, i.e. upon reaching the softening point of the distillation residue of 47 ° C (the condition of more than 35 ° C is met), the residue accumulated in the intermediate tank was dosed in small portions into the working storage of the initial mixture of coal tar and oil refined product and, together with the feedstock, was fed for reprocessing to obtain oil-and-coal binder pitch with the properties specified in table. 2.

Example 10 (in continuous mode). A mixture of coal tar, as in example 9, and heavy gas oil catalytic cracking, as in example 1, in the ratio of coal tar: heavy gas oil 25:75 wt.% Was heated in a tube furnace to 440 ° C, then the heated resin mixture with a feed rate of 9 t / h was fed to the evaporator, where there was a separation into vapors of distillate fractions, which entered the rectification column, and a non-distillable distillation residue. The softening point of the non-distillable distillation residue was 36 ° C. The non-distillable distillation residue was sent to a still reactor, where it was processed at 340-350 ° C at a flow rate of 120 dm ³ / kg of heated air pitch. The resulting oil-and-coal binder pitch had the properties indicated in table. 2, the mass fraction of ash 0.2%.

The non-distillation residue of the distillation, the softening point of which was less than 35 ° C, was sent to an intermediate vessel. After the process has entered the steady state, i.e. when the softening temperature of the distillation residue reached 35 ° C (the condition of more than 35 ° C was fulfilled), the residue accumulated in the intermediate tank was dosed in small portions into the working storage of the initial mixture of coal tar and oil refined product and, together with the feedstock, was fed for reprocessing to obtain oil-and-coal binder pitch with the properties specified in table. 2.

Example 11. Non-oil-coal binder pitch, obtained according to example 10, was mixed with calcined petroleum coke in a ratio of 29.3 wt.% Pitch, 70.7 wt.% Coke. Mixing was carried out at a temperature of 195 ° C. The resulting molten anode mass was stuffed into metal molds and burned in a shaft furnace at a temperature of 960 ° C for 3 hours, the rate of temperature rise to 960 ° C was 15 ° C. The cooled anode mass after firing was drilled with a hollow drill with an inner diameter of 50 mm and the quality indicators indicated in table were determined. 3.

Example 12. Non-oil-coal binder pitch, obtained according to example 10, was mixed with calcined petroleum coke in a ratio of 14.5 wt.% Pitch, 85.5 wt.% Coke. Mixing was carried out at a temperature of 178 ° C. The pressing of the green anode was carried out at a temperature of 160 ° C for 36 s. The green anode was fired in a shaft furnace at a temperature of 1100 ° C. Cores were drilled from the baked anode with a hollow drill with an inner diameter of 50 mm and the quality indicators of the resulting product were determined, indicated in table. 4.

table 2

Example Coal tar: refined product ratio Heat treatment temperature (° C) and holding (h) Τρι, ° C Air handling conditions for pitch Parameters of oxidized oil and coal pitch Т, ° C Air consumption, dm ³ / kg pitch Tr ₂ , ° С a,% αι,% V,% NS., % Benz [a] pyrene,% 1 49:51 430 ° C, 2 h 66 340 thirty 90 39 AND 53 56 0.41 2 40:60 430 ° C, 2 h 61 340 40 85 35 nine 54 54 0.38 3 25:75 430 ° C, 2 h 60 340 36 85 34 7 55 53 0.37 4 30:70 430 ° C, 2 h 57 340 36 90 34 4 57 52 0.39 5 25:70 440 ° C, 2 h 46 340 70 87 34 3 57 52 0.39 6 49:51 400 ° C, 4 h 51 360 80 86 34 ten 55 55 0.36 7 25:75 440 ° C, 1h 69 325 55 90 35 eight 56 53 0.28 eight 60:40 430 ° C, 2 h 70 340 36 92 41 13 51 - - nine 49:51 436 ° C 47 340 70 90 35 AND 55 56 0.43 ten 25:75 440 ° C 35 340-350 120 86 32 nine 56 54 0.38

where Tp ₁ is the softening point of low-temperature pitch after heat treatment and holding according to the Ring and rod method, ° C

Tr ₂ - softening temperature of oxidized pitch according to the Ring and rod method, ° C;

K. o. - coke residue at 550 ° C,%;

α - mass fraction of substances insoluble in toluene,%;

α1 - mass fraction of substances insoluble in quinoline,%;

V - mass fraction of volatile substances,%;

Table 3

Anode mass quality index Meaning electrical resistivity, μOhm-m 68 compressive strength, kg / cm ² 321 bending strength, kg / cm ² 134 total porosity,% 29.1 reactivity in CO ₂ , mg / cm ² -h 10.9 crumbling in СО ₂ , mg / cm ² -h 0.2 reactivity in air, mg / cm ² -h 142

Table 4

Quality index of the baked anode Meaning electrical resistivity, μOhm-m 56 compressive strength, kg / cm ² 392 apparent density, g / cm ² 1.57 gas permeability, nPm 1.8 Residue of the sample from the carboxyl reaction (CRR),% 88 Dust from carboxyl reaction (CRR),% 2

The result of example 8 (according to the prototype) shows that when using coal tar and a refined oil product in a ratio of 60:40, the content of the a1-fraction in the resulting product (oxide-6 038571 petroleum-coal tar pitch) is higher than 12%, which does not meet the requirements of GOST 10200, cm ...

tab. 1.

The results of examples 1-7, 9-10 indicate the compliance of the oil-and-coal binder pitch obtained by the proposed method with the requirements of GOST 10200 for the quality of grade B pitch, the softening temperature of the oil-coal binder pitch obtained by the proposed method is from 85 to 90 ° C, the content of insoluble substances in toluene, 32-39%, the content of benzo [a] pyrene is not more than 0.43%. The method allows to expand the raw material base for obtaining binder pitches for electrodes.

The result of example 11 testifies to the suitability of the anode mass obtained on the basis of petroleum-coal binder pitch according to this method for use in a self-baking anode of an aluminum electrolyzer.

The result of example 12 indicates the suitability of the petroleum-coal binder obtained by the proposed method for the manufacture of products, such as pre-baked anodes, which can be produced in the electrode industry and used in the metallurgical industry.

Claims (10)

CLAIM 1. A method of producing a petroleum-coal binder pitch, including mixing coal tar and a refined oil product in a given ratio, heat treatment of the resulting mixture in a liquid phase with separation of distillate fractions and a non-distillable distillation residue in the form of low-temperature pitch, air oxidation of a non-distillable non-distillation residue, a binder the fact that the ratio of coal tar and oil refined product during mixing is 49: 51-25: 75 wt.%, the heat treatment of the resulting mixture is carried out until a distillation residue is obtained with a softening temperature of at least 35 ° C in continuous or batch modes, and the air consumption during oxidation low-temperature pitch is 30-120 dm ³ / kg pitch. 2. The method according to claim 1, characterized in that a liquid oil product with a high content of aromatic compounds is used, which satisfies the following conditions: density at 20 ° C not less than 1020 kg / m ³ , viscosity at 100 ° C not more than 20 cSt, coking capacity not less than 5%, distillation of the fraction boiling up to 300 ° C, not more than 5%. 3. The method according to claim 1, characterized in that a coal tar with a density of 11901225 kg / m ³ and a content of substances insoluble in quinoline of at least 4 wt.% Is used. 4. The method according to claim 1, characterized in that the heat treatment of the mixture is carried out at a temperature of 400-440 ° C. 5. The method according to claim 1, characterized in that the oxidation temperature of the low-temperature pitch is 325-360 ° C. 6. The method according to claim 1, characterized in that, in continuous mode, the non-distillable distillation residue having a softening point of less than 35 ° C, before oxidation, is sent to the stage of re-thermal treatment by returning it to the stage of mixing coal tar and oil refined product. 7. A method according to claim 1, characterized in that, in a batch mode, heat treatment of the resulting mixture is carried out for 1-4 hours until a non-distillable distillation residue is obtained, having a softening temperature of at least 35 ° C. 8. Non-refined coal binder pitch obtained by the method according to any one of claims 1-7. 9. Anode mass, including oil-and-coal binder pitch, characterized in that the oil-and-coal binder pitch is obtained by the method according to any one of claims 1 to 7. 10. A product of the metallurgical or electrode industry, for the production of which a coal-oil binder pitch is used, characterized in that the oil-coal binder pitch is obtained by the method according to any one of claims 1 to 7.