A high-strength and high-specific-surface-area coal-based powdered activated carbon and its preparation method

Abstract

The present invention relates to a high-strength and high-specific-surface-area coal-based powdered activated carbon and a preparation method thereof, belonging to the technical field of activated carbon preparation. In the present invention, anthracite, lignite, and weakly caking coal are mixed and ground and heat-treated, so that the prepared activated carbon has more types of pore structures, thereby increasing the specific surface area and improving its adsorption capacity. Subsequent steps such as phosphoric acid treatment, addition of zinc chloride, and ultrasonic treatment help to further optimize the pore structure and increase the specific surface area; the formula of the present invention enables the final product to have a higher specific surface area and porosity. The addition of coal tar pitch and alumina helps to improve the mechanical strength of the activated carbon, making it more durable during use. The chemical components in the coal tar pitch will promote the formation and expansion of pores during the carbonization process, thereby optimizing the pore structure of the activated carbon. The addition of alumina can combine with the surface of the activated carbon through chemical or physical actions to form a stable protective film or modified layer.

Description

Technical Field

[0001] The present invention belongs to the technical field of activated carbon preparation, and relates to a bituminous coal powder activated carbon with high strength and high specific surface area and a preparation method thereof. Background Art

[0002] The main raw material of bituminous coal powder activated carbon is coal, especially high-quality anthracite. This coal type has low ash content and high fixed carbon content, and is an ideal raw material for preparing high-quality activated carbon.

[0003] Bituminous coal granular activated carbon has high strength, well-developed pores, large specific surface area, especially large micropore volume and unique advantages. Bituminous coal activated carbon has strong adsorption capacity for various organic matters, free chlorine in water and harmful gases in the air. It is an excellent adsorbent for deep purification of urban drinking water and is used to remove bacteria and poisonous gases in the air. Bituminous coal activated carbon has a well-developed pore structure, good chemical stability and mechanical strength, and is an excellent broad-spectrum carbonaceous adsorption material. Bituminous coal activated carbon can be mainly divided into bituminous coal granular activated carbon and bituminous coal powdered activated carbon. According to different uses, it can be divided into activated carbon for water purification, air purification, decolorization, solvent recovery, injection, protection, etc. Due to its acid resistance, alkali resistance, heat resistance and convenient regeneration, activated carbon is an essential carbonaceous adsorption material in modern industrial production and environmental protection. Summary of the Invention

[0004] The purpose of the present invention is to provide a bituminous coal powder activated carbon with high strength and high specific surface area and a preparation method thereof, which has the characteristics of wear resistance and high specific surface area.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A bituminous coal powder activated carbon with high strength and high specific surface area, the raw materials of the activated carbon are as follows, by mass percentage, 75-85% of modified coal powder, 3-5% of coal tar pitch, 3-5% of alumina, 3-5% of dispersant, 5-10% of deionized water.

[0007] Among them, the preparation method of the modified coal powder is:

[0008] S1: Mix anthracite, lignite and weakly caking coal in a mass ratio of (2-5):2:1, grind in a ball mill at a rotation speed of 500 r / min for 4-6 h, and sieve to obtain mixture A;

[0009] S2: Spread mixture A evenly with a thickness of 3-5 cm, first introduce steam for heat treatment, the heat treatment duration is 0.5-2 h, the heat treatment temperature is 800-950 °C, then introduce carbon dioxide for purging, and slowly heat up to 120 °C while purging, and continue purging at 120 °C for 6 h to obtain mixture B;

[0010] S3: Disperse mixture B in a phosphoric acid solution with a mass fraction of 10% to obtain a solid-liquid mixture C with a mass fraction of 30 - 50%. Stir at a speed of 200 r / min. While stirring, dropwise add a zinc chloride solution with a mass fraction of 20%. The stirring duration is 2 h. Among them, the volume ratio of the solid-liquid mixture C to the zinc chloride solution is 2:1. After stirring, ultrasonicate for 0.5 h, filter, and dry at 110 °C for 8 h to obtain mixture D;

[0011] S4: Under an anaerobic environment, carry out a carbonization reaction on mixture D. The carbonization temperature is 550 - 650 °C, and the carbonization duration is 4 - 5 h. After carbonization, cool to room temperature to obtain a carbonized product E;

[0012] S5: Add 2 - 3 wt% of oxalic acid and 0.5 - 1 wt% of zinc chloride to the carbonized product E. Grind at a speed of 500 r / min for 1 h. Dry the ground mixture at 110 °C for 8 h. After drying, transfer it to a muffle furnace under a nitrogen atmosphere and calcine at 400 °C for 2 h. After calcination, cool to room temperature and grind to a particle size of 300 mesh to obtain the modified pulverized coal.

[0013] Further, the dispersant is polyethylene glycol with a number-average molecular weight of 20000 - 25000.

[0014] Further, in S1, the ash content of anthracite, lignite, and weakly caking coal is 20 - 25 wt%.

[0015] Further, in S1, the particle size of mixture A is 200 mesh.

[0016] Further, in S2, the amount of water vapor introduced is 1.5 - 2 kg / h.

[0017] Further, in S2, the flow rate of carbon dioxide introduced is 10 m / s.

[0018] Further, in S3, the dropping rate of the zinc chloride solution is 5 drops / second.

[0019] Further, in S5, the heating rate of the muffle furnace is 5 °C / min.

[0020] A preparation method of a high-strength and high-specific-surface-area coal-based powdered activated carbon. The specific process of the coal-based powdered activated carbon preparation method is as follows.

[0021] S91: Mix the modified pulverized coal, coal tar pitch, and alumina evenly according to the formula ratio and grind at a speed of 500 - 600 r / min for 4 h to obtain mixture F;

[0022] S92: Disperse mixture F in deionized water, add a dispersant, ultrasonicate for 2 h, filter, freeze in liquid nitrogen for 15 - 20 min, and dry at -70 to -50 °C under vacuum for 10 - 12 h to obtain mixture G;

[0023] S93: Grind and pulverize mixture G to obtain the coal-based powdered activated carbon.

[0024] Furthermore, the particle size of the coal-based powdered activated carbon prepared in S93 is 500 mesh.

[0025] By mixing different types of coal (anthracite, lignite, weakly caking coal) and performing grinding and heat treatment, the prepared activated carbon has more types of pore structures, thereby increasing the specific surface area and improving its adsorption capacity. Subsequent steps such as phosphoric acid treatment, zinc chloride addition, and ultrasonic treatment help to further optimize the pore structure and increase the specific surface area.

[0026] During the preparation process, through multiple heat treatments, carbonizations, and calcination in a nitrogen atmosphere, these steps improve the chemical stability of the activated carbon, enabling it to maintain stable mechanical strength under various conditions. Long-term grinding and heat treatment will make the bonding between activated carbon particles closer, thereby improving its compressive and abrasion resistance, which is crucial for the long-term stability and durability of activated carbon in practical applications.

[0027] Anthracite has good hardness and high chemical stability, and is suitable for directly crushing or grinding and then forming to manufacture granular carbon. The activated carbon made from it has well-developed micropores, a large micropore volume, and a large specific surface area, and has good adsorption performance for vapors and gases; lignite is rich in resources, low in price, has many pores, and is rich in functional groups, especially having good adsorption, complexation, and exchange properties. Its carbonization process directly forms a solid state without generating liquid, which is conducive to maintaining the structure of the activated carbon; weakly caking coal is between anthracite and lignite, having both a certain hardness and a certain pore structure, and is suitable for mixing with other coal types to adjust the performance of the final product.

[0028] The high hardness and high adsorption performance of anthracite can be combined with the abundant pores and functional groups of lignite, while weakly caking coal can play a bridging role in between, making the mixed raw materials more uniform and stable. During the pyrolysis and activation processes, the coal quality structures of different coal types will change, forming different pore structures. The synergistic effect of these pores can optimize the pore structure of activated carbon, making it have both sufficient micropores to provide a high specific surface area and excellent adsorption performance, and contain an appropriate amount of mesopores and macropores to improve the mass transfer efficiency and adsorption kinetics; during the pyrolysis and activation processes, crosslinking, cracking, and polycondensation reactions will occur between different coal types in the mixed raw materials. These reactions can promote the formation of activated carbon and the development of pore structure. The functional groups in lignite can react with the carbon skeleton in anthracite to form more stable chemical bonds and more complex pore structures. At the same time, weakly caking coal can also act as a catalyst or reaction intermediate to promote the progress of these chemical reactions.

[0029] Steam heat treatment can improve the caking index of coal and optimize the pyrolysis performance of coal; steam treatment can promote the decomposition of oxygen-containing functional groups in coal, reduce the hydrogen consumption during the coal utilization process, and thus increase the calorific value of coal; the hydrogen in steam can be added to coal through the hydrolysis of oxygen-containing functional groups under the synergistic effect of free radical and ionic effects, effectively supplying hydrogen to stabilize medium molecular weight free radical fragments; appropriate steam heat treatment also helps to reduce pollutants generated during the combustion or gasification process of coal, such as sulfur oxides and nitrogen oxides, etc.

[0030] Steam heat treatment heats pulverized coal and introduces steam, enabling the organic matter in coal to undergo chemical reactions with steam at high temperatures. These reactions include pyrolysis, hydrolysis, and redox reactions, which can change the chemical structure and physical properties of coal. Specifically, steam can penetrate into the pores of coal and react with elements such as carbon, hydrogen, and oxygen in coal to generate gas products such as CO, CO2, and H2 and solid residues. These reactions can break the chemical bonds in coal and form new pore structures, thereby improving the adsorption, reactivity, and utilization rate of coal.

[0031] Carbon dioxide treatment can improve the microscopic structure of coal, making it more easily react with gasifying agents or combustion agents, thereby increasing the conversion rate and utilization rate of coal; compared with traditional coal treatment methods, the carbon dioxide treatment process has low energy consumption and does not produce secondary pollution.

[0032] Phosphorylation heat treatment forms a phosphorylated layer through a chemical reaction between the introduced phosphate and the surface of pulverized coal. This phosphorylated layer can significantly enhance the wear resistance, corrosion resistance, and oxidation resistance of pulverized coal, which is of great significance for improving the stability and durability of pulverized coal during subsequent processing and use. Phosphoric acid also plays a skeletal role during the heat treatment process and is accompanied by the formation of micropores, which helps optimize the pore structure of pulverized coal and improve its adsorption performance and reactivity. The ionization and dehydration of phosphoric acid can promote the elimination of hydroxyl groups and the expansion of cross-linked structures in pulverized coal, thus facilitating subsequent chemical reactions.

[0033] Zinc chloride, as a catalyst, can accelerate the cracking and conversion process of pulverized coal at high temperatures, thereby changing the chemical composition and physical properties of pulverized coal. Zinc chloride can react with sulfides in coal, causing them to precipitate and separate from the pulverized coal, which helps reduce the emissions of sulfur oxide pollutants generated during the combustion or gasification of pulverized coal. Through the treatment with zinc chloride, the combustible components in pulverized coal can be more easily extracted and utilized, thus improving the utilization rate of pulverized coal.

[0034] The role of zinc chloride in the heat treatment of pulverized coal is mainly based on its catalytic performance and reaction ability with substances in coal. At high temperatures, zinc chloride can penetrate into the pores of pulverized coal and react with the organic and inorganic substances therein. These reactions may include processes such as cracking, oxidation, and reduction, resulting in changes in the chemical composition and physical properties of pulverized coal. In particular, the reaction of zinc chloride with sulfides in coal can significantly reduce the sulfur content in pulverized coal and reduce the pollution generated during its combustion.

[0035] Through the carbonization reaction, volatile components and other combustible components in pulverized coal are further removed, thereby increasing the carbon content of pulverized coal, which helps improve the combustion performance and calorific value of pulverized coal. During the carbonization process, the structure of pulverized coal changes, the porosity increases, and the surface area increases. These changes are conducive to improving the adsorption capacity and reactivity of pulverized coal. At high temperatures, the organic substances in pulverized coal undergo pyrolysis reactions to generate gases such as CO, CO2, and H2 and coke. These gases are gradually released as the temperature rises, leaving a solid product mainly composed of carbon. As the volatile components are removed, the pore structure of pulverized coal changes and the porosity increases, which helps pulverized coal react or adsorb better with other substances in subsequent applications.

[0036] Oxalic acid can remove metal ions and other impurities in pulverized coal, improving the purity of pulverized coal. Zinc chloride, as a catalyst and additive, can promote the dispersion of pulverized coal particles and prevent agglomeration during subsequent applications. At the same time, the addition of zinc chloride can also continue to participate in the chemical reactions on the surface of pulverized coal to form a stable protective layer. After roasting, carbon-oxygen bonds, carbon-chlorine bonds, etc. are formed on the surface of pulverized coal. The formation of these chemical bonds helps change the surface properties and catalytic performance of pulverized coal, form catalytically active sites, and improve the catalytic performance of pulverized coal in reactions.

[0037] The formulation of the present invention combines various components beneficial to the adsorption performance of activated carbon, enabling the final product to have a higher specific surface area and porosity, thereby enhancing the adsorption capacity for pollutants such as organic substances and heavy metal ions. The addition of coal tar pitch and alumina helps to improve the mechanical strength of the activated carbon, making it more durable during use. The chemical components in coal tar pitch will promote the formation and expansion of pores during the carbonization process, thereby optimizing the pore structure of the activated carbon. The addition of alumina can combine with the surface of the activated carbon through chemical or physical actions to form a stable protective film or modified layer, which can enhance its acid and alkali resistance and antioxidant properties; the addition of a dispersant helps to improve the dispersion of activated carbon particles in the solution, making it easier to handle and operate in practical applications.

[0038] Advantages of the present invention:

[0039] (1) By mixing anthracite, lignite, and weakly caking coal and performing grinding and heat treatment, the prepared activated carbon has more types of pore structures, thereby increasing the specific surface area and improving its adsorption capacity. Subsequent steps such as phosphoric acid treatment, addition of zinc chloride, and ultrasonic treatment help to further optimize the pore structure and increase the specific surface area;

[0040] (2) The formulation of the present invention combines various components beneficial to the adsorption performance of activated carbon, enabling the final product to have a higher specific surface area and porosity, thereby enhancing the adsorption capacity for pollutants such as organic substances and heavy metal ions. The addition of coal tar pitch and alumina helps to improve the mechanical strength of the activated carbon, making it more durable during use. The chemical components in coal tar pitch will promote the formation and expansion of pores during the carbonization process, thereby optimizing the pore structure of the activated carbon. The addition of alumina can combine with the surface of the activated carbon through chemical or physical actions to form a stable protective film or modified layer, which can enhance its acid and alkali resistance and antioxidant properties; the addition of a dispersant helps to improve the dispersion of activated carbon particles in the solution, making it easier to handle and operate in practical applications. Detailed implementation mode

[0041] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following combines examples to detail the specific implementation mode, structure, characteristics, and effects according to the present invention.

[0042] Example 1

[0043] 80% modified pulverized coal, 5% coal tar pitch, 5% alumina, 5% polyethylene glycol - 20000, 5% deionized water,

[0044] Among them, the preparation method of the modified pulverized coal is:

[0045] S1: Mix anthracite, lignite, and weakly caking coal in a mass ratio of 4:2:1. The ash content of anthracite, lignite, and weakly caking coal is 20 wt%. Grind them in a ball mill at a speed of 500 r / min for 5 h, then sieve to obtain mixture A, and the particle size of mixture A is 200 mesh.

[0046] S2: Spread mixture A evenly with a thickness of 3 cm. First, conduct heat treatment by introducing steam. The amount of steam introduced is 2 kg / h, the treatment duration is 1 h, and the heat treatment temperature is 900 °C. Then, introduce carbon dioxide for purging. The flow rate of carbon dioxide introduced is 10 m / s. While purging, slowly heat up to 120 °C and continue purging at 120 °C for 6 h to obtain mixture B.

[0047] S3: Disperse mixture B in a phosphoric acid solution with a mass fraction of 10% to obtain a solid-liquid mixture C with a mass fraction of 40%. Stir at a speed of 200 r / min. While stirring, dropwise add a zinc chloride solution with a mass fraction of 20%. The dropping rate of the zinc chloride solution is 1 drop every 5 seconds, and the stirring duration is 2 h. Among them, the volume ratio of solid-liquid mixture C to the zinc chloride solution is 2:1. After stirring, ultrasonicate for 0.5 h, filter, and dry at 110 °C for 8 h to obtain mixture D.

[0048] S4: Under an anaerobic environment, conduct a carbonization reaction on mixture D. The carbonization temperature is 600 °C, and the carbonization duration is 4 h. After carbonization is completed, cool to room temperature to obtain carbonized product E.

[0049] S5: Add 3 wt% oxalic acid and 1 wt% zinc chloride to carbonized product E, grind at a speed of 500 r / min for 1 h, dry the ground mixture at 110 °C for 8 h. After drying, transfer it to a muffle furnace under a nitrogen atmosphere and bake at 400 °C for 2 h. The heating rate of the muffle furnace is 5 °C / min. After baking, cool to room temperature and grind to a particle size of 300 mesh to obtain the modified pulverized coal.

[0050] The specific process of the preparation method of the coal-based powdered activated carbon is as follows.

[0051] S91: Mix the modified pulverized coal, coal tar pitch, and alumina evenly according to the formula ratio, and grind at a speed of 500 - 600 r / min for 4 h to obtain mixture F.

[0052] S92: Disperse mixture F in deionized water, add a dispersant, ultrasonicate for 2 h, filter, put it into liquid nitrogen and freeze for 20 min, and dry under a vacuum state at -60 °C for 12 h to obtain mixture G.

[0053] S93: Grind and crush mixture G to obtain the coal-based powdered activated carbon. The particle size of the prepared coal-based powdered activated carbon is 500 mesh.

[0054] Example 2

[0055] 85% modified pulverized coal, 3% coal tar pitch, 3% alumina, 3% polyethylene glycol - 25000, 6% deionized water,

[0056] Among them, the preparation method of the modified pulverized coal is as follows:

[0057] S1: Mix anthracite, lignite, and weakly caking coal in a mass ratio of 2:2:1. The ash content of anthracite, lignite, and weakly caking coal is 25 wt%. Grind in a ball mill at a speed of 500 r / min for 6 h, and then screen to obtain mixture A. The particle size of mixture A is 200 mesh;

[0058] S2: Spread mixture A evenly with a thickness of 3 cm. First, introduce steam for heat treatment. The amount of steam introduced is 1.5 kg / h, the treatment duration is 0.5 h, and the heat treatment temperature is 800 °C. Then, introduce carbon dioxide for purging. The flow rate of carbon dioxide introduced is 10 m / s. While purging, slowly heat up to 120 °C and continue purging at 120 °C for 6 h to obtain mixture B;

[0059] S3: Disperse mixture B in a phosphoric acid solution with a mass fraction of 10% to obtain a solid - liquid mixture C with a mass fraction of 50%. Stir at a speed of 200 r / min. While stirring, dropwise add a zinc chloride solution with a mass fraction of 20%. The dropping rate of the zinc chloride solution is 5 seconds per drop, and the stirring duration is 2 h. Among them, the volume ratio of solid - liquid mixture C to the zinc chloride solution is 2:1. After stirring, ultrasonicate for 0.5 h, filter, and dry at 110 °C for 8 h to obtain mixture D;

[0060] S4: Carry out a carbonization reaction on mixture D in an anaerobic environment. The carbonization temperature is 550 °C, and the carbonization duration is 4 - 5 h. After carbonization is completed, cool to room temperature to obtain a carbonized product E;

[0061] S5: Add 2 wt% oxalic acid and 0.5 wt% zinc chloride to the carbonized product E, grind at a speed of 500 r / min for 1 h, dry the ground mixture at 110 °C for 8 h. After drying, transfer it to a muffle furnace under a nitrogen atmosphere and calcine at 400 °C for 2 h. The heating rate of the muffle furnace is 5 °C / min. After calcination, cool to room temperature and grind to a particle size of 300 mesh to obtain the modified pulverized coal.

[0062] The specific process of the preparation method of the coal - based powdered activated carbon is as follows,

[0063] S91: Mix the modified pulverized coal, coal tar pitch, and alumina evenly according to the formula ratio, and grind at a speed of 500 - 600 r / min for 4 h to obtain mixture F;

[0064] S92: Disperse mixture F in deionized water, add a dispersant, sonicate for 2 h, filter, freeze in liquid nitrogen for 15 min, and dry at -50 °C under vacuum for 10 h to obtain mixture G;

[0065] S93: Grind and pulverize mixture G to obtain the coal-based powdered activated carbon, and the particle size of the prepared coal-based powdered activated carbon is 500 mesh.

[0066] Example 3

[0067] 75% modified pulverized coal, 5% coal tar pitch, 5% alumina, 5% polyethylene glycol - 20000, 10% deionized water,

[0068] Among them, the preparation method of the modified pulverized coal is as follows:

[0069] S1: Mix anthracite, lignite, and weakly caking coal in a mass ratio of 5:2:1. The ash content of anthracite, lignite, and weakly caking coal is 20 wt%. Grind in a ball mill at a speed of 500 r / min for 6 h, and sieve to obtain mixture A. The particle size of mixture A is 200 mesh;

[0070] S2: Spread mixture A evenly with a thickness of 5 cm. First, introduce steam for heat treatment. The amount of steam introduced is 2 kg / h, and the treatment duration is 2 h. The heat treatment temperature is 950 °C. Then, introduce carbon dioxide for purging. The flow rate of carbon dioxide introduced is 10 m / s. While purging, slowly heat up to 120 °C and continue purging at 120 °C for 6 h to obtain mixture B;

[0071] S3: Disperse mixture B in a phosphoric acid solution with a mass fraction of 10% to obtain a solid-liquid mixture C with a mass fraction of 30%. Stir at a speed of 200 r / min. While stirring, dropwise add a zinc chloride solution with a mass fraction of 20%. The dropping rate of the zinc chloride solution is 5 drops / second, and the stirring duration is 2 h. Among them, the volume ratio of solid-liquid mixture C to the zinc chloride solution is 2:1. After stirring, sonicate for 0.5 h, filter, and dry at 110 °C for 8 h to obtain mixture D;

[0072] S4: Carry out a carbonization reaction on mixture D in an anaerobic environment. The carbonization temperature is 650 °C, and the carbonization duration is 4 h. After carbonization, cool to room temperature to obtain the carbonized product E;

[0073] S5: Add 3 wt% of oxalic acid and 1 wt% of zinc chloride to the carbonized product E, grind it at a rotation speed of 500 r / min for 1 h, dry the obtained mixture at 110 °C for 8 h, transfer it to a nitrogen atmosphere after drying, calcine it in a muffle furnace at 400 °C for 2 h, with the heating rate of the muffle furnace being 5 °C / min, cool it to room temperature after calcination, and grind it to a particle size of 300 mesh to obtain the modified pulverized coal.

[0074] The specific process of the preparation method of the coal-based powdered activated carbon is as follows.

[0075] S91: Mix the modified pulverized coal, coal tar pitch, and alumina evenly according to the formula ratio, and grind them at a rotation speed of 500 - 600 r / min for 4 h to obtain a mixture F.

[0076] S92: Disperse the mixture F in deionized water, add a dispersant, ultrasonicate for 2 h, filter it, put it into liquid nitrogen for freezing for 20 min, and dry it under vacuum at -70 °C for 12 h to obtain a mixture G.

[0077] S93: Grind and crush the mixture G to obtain the coal-based powdered activated carbon, and the particle size of the prepared coal-based powdered activated carbon is 500 mesh.

[0078] Comparative Example 1

[0079] In this comparative example, only anthracite and weakly caking coal are used during the modification process of the pulverized coal, and the remaining steps are the same as those in Example 1.

[0080] Comparative Example 2

[0081] In this comparative example, only lignite and weakly caking coal are used during the modification process of the pulverized coal, and the remaining steps are the same as those in Example 1.

[0082] Comparative Example 3

[0083] In this comparative example, the steam heat treatment and carbon dioxide treatment in S2 are not carried out during the modification process of the pulverized coal, and the remaining steps are the same as those in Example 1.

[0084] Comparative Example 4

[0085] In this comparative example, the phosphoric acid and zinc chloride treatment in S3 are not carried out during the modification process of the pulverized coal, and the remaining steps are the same as those in Example 1.

[0086] Comparative Example 5

[0087] In this comparative example, the oxalic acid and zinc chloride treatment in S5 are not carried out during the modification process of the pulverized coal, and the remaining steps are the same as those in Example 1.

[0088] Comparative Example 6

[0089] In this comparative example, coal tar pitch is not added during the preparation process, and the remaining steps are the same as those in Example 1.

[0090] Comparative Example 7

[0091] In this comparative example, alumina is not added during the preparation process, and the remaining steps are the same as those in Example 1.

[0092] The performance of the examples and comparative examples was tested. The mechanical strength was tested according to GB / T7702.3 - 2008, and the specific surface area was tested according to GB / T7702.20 - 2008. The test results are summarized in the following table.

[0093] Mechanical strength (%) <![CDATA[Specific surface area (m 2 / g)]]> Example 1 99 1305 Example 2 98 1281 Example 3 98 1287 Comparative Example 1 96 1002 Comparative Example 2 89 1129 Comparative Example 3 93 984 Comparative Example 4 91 1135 Comparative Example 5 91 1142 Comparative Example 6 94 990 Comparative Example 7 90 1192

[0094] It can be seen from the experiments that modifying the pulverized coal makes the prepared activated carbon have better mechanical strength and specific surface area. Adding coal tar pitch to the formula makes the activated carbon have a better specific surface area, and adding alumina improves the mechanical strength of the activated carbon.

[0095] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A high-strength and high-specific-surface-area coal-based powdered activated carbon, characterized in that: The activated carbon raw materials are as follows: by mass percentage, modified coal powder 75-85%, coal tar 3-5%, aluminum oxide 3-5%, dispersant 3-5%, deionized water 5-10%, Wherein, the preparation method of the modified coal powder is: S1: anthracite, lignite and weakly caking coal are mixed in a mass ratio of (2-5):2:1, ground in a ball mill at a speed of 500 r / min for 4-6 h, and sieved to obtain a mixture A; S2: Spread the mixture A evenly to a thickness of 3-5 cm, first introduce water vapor for heat treatment for 0.5-2 h at a temperature of 800-950°C, then introduce carbon dioxide for purging, slowly raise the temperature to 120°C while purging, and continue purging at 120°C for 6 h to obtain a mixture B; S3: Disperse the mixture B in a phosphoric acid solution with a mass fraction of 10% to obtain a solid-liquid mixture C with a mass fraction of 30-50%, stir at a speed of 200 r / min, and dropwise add a zinc chloride solution with a mass fraction of 20% while stirring. The stirring time is 2 hours, wherein the volume ratio of the solid-liquid mixture C to the zinc chloride solution is 2:

1. After the stirring is completed, ultrasonicate for 0.5 hours, filter, and dry at 110°C for 8 hours to obtain a mixture D; S4: In an oxygen-free environment, the mixture D is subjected to a carbonization reaction at a carbonization temperature of 550-650° C. for a carbonization time of 4-5 h. After the carbonization is completed, the mixture is cooled to room temperature to obtain a carbonized product E. S5: adding 2-3 wt% oxalic acid and 0.5-1 wt% zinc chloride to the carbonized product E, grinding at a speed of 500 r / min for 1 h, drying the ground mixture at 110° C. for 8 h, transferring it to a nitrogen atmosphere after drying, and roasting it in a muffle furnace at 400° C. for 2 h, cooling it to room temperature after roasting, and grinding it to a particle size of 300 meshes to obtain the modified coal powder; The specific process of the method for preparing coal-based powdered activated carbon is as follows: S91: uniformly mix the modified coal powder, coal tar pitch and alumina according to the formula ratio, and grind at a speed of 500-600 r / min for 4 h to obtain a mixture F; S92: Disperse the mixture F in deionized water, add a dispersant, perform ultrasonication for 2 h, filter, freeze in liquid nitrogen for 15-20 min, and dry at -70--50° C. under vacuum for 10-12 h to obtain a mixture G; S93: Grind the mixture G to obtain the coal-based powdered activated carbon.

2. The high-strength and high-specific-surface-area coal-based powdered activated carbon according to claim 1, characterized in that: The dispersant is polyethylene glycol, and the number average molecular weight is 20000-25000.

3. The high-strength and high-specific-surface-area coal-based powdered activated carbon according to claim 1, characterized in that: The ash content of anthracite, lignite and slightly sticky coal in S1 is 20-25wt%.

4. The high-strength and high-specific-surface-area coal-based powdered activated carbon according to claim 1, characterized in that: The particle size of the mixture A in S1 is 200 mesh.

5. The high-strength and high-specific-surface-area coal-based powdered activated carbon according to claim 1, characterized in that: The amount of water vapor introduced into S2 is 1.5-2 kg / h.

6. The high-strength and high-specific-surface-area coal-based powdered activated carbon according to claim 1, characterized in that: The flow rate of carbon dioxide in S2 is 10m / s.

7. The high-strength and high-specific-surface-area coal-based powdered activated carbon according to claim 1, characterized in that: The dropping rate of the zinc chloride solution in S3 is 5 seconds / drop.

8. The high-strength and high-specific-surface-area coal-based powdered activated carbon according to claim 1, characterized in that: The heating rate of the muffle furnace in S5 is 5°C / min.

9. The high-strength and high-specific-surface-area coal-based powdered activated carbon according to claim 1, characterized in that: The particle size of the coal-based powdered activated carbon prepared in S93 is 500 mesh.