Preparation process of special fly ash for concrete for construction

Abstract

The invention discloses a preparation process of special fly ash for concrete for construction, and relates to the technical field of fly ash preparation. Fly ash and sodium chloride are mixed, distilled water is added, uniform stirring is performed, and a primary mixed solution A is obtained; adding a modifier and a surfactant into the primary mixed solution A to obtain a composite mixed solution B; carrying out airflow dispersion treatment on the composite mixed solution B to obtain modified fly ash slurry; and separating the modified fly ash slurry through a centrifugal machine to obtain solid fly ash, and drying the solid fly ash to obtain the final fly ash for construction. According to the fly ash modification process, the sodium chloride, the modifier, the surfactant and other auxiliaries are added, the airflow dispersion technology is combined, the surface activity and reactivity of the fly ash are remarkably improved, meanwhile, the airflow dispersion technology effectively improves the dispersity of the fly ash, the contact area of the fly ash and cement paste is increased, and the fly ash modification effect is improved. Therefore, the overall performance of the fly ash is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fly ash preparation, and specifically relates to a preparation process for fly ash specialized for concrete used in construction. Background Art

[0002] Fly ash is an industrial by-product generated by coal-fired power plants, with its main components being silicon dioxide and aluminum. Due to its low activity, the application effect of fly ash in construction concrete is limited. Therefore, many studies are dedicated to improving its performance through the preparation process of modified fly ash, making it better meet the requirements of concrete and enhancing its strength and durability.

[0003] Traditional methods for modifying fly ash usually involve physical, chemical, or biological modification means. However, these methods are either inefficient or unable to effectively improve the overall performance of fly ash. Therefore, a new method is needed that can not only increase the activity of fly ash but also improve its compatibility with concrete to achieve the purpose of enhancing the performance of concrete. Currently, there is no unified standard for the preparation of modified fly ash on the market. Due to the diverse nature and sources of fly ash, there is no unified specification for various modification processes, resulting in significant differences in the application effects of fly ash. Therefore, developing a stable and easy-to-operate preparation process for modified fly ash has become an urgent need in the industry. Summary of the Invention

[0004] To solve the above technical problems, a preparation process for fly ash specialized for concrete used in construction is provided, and this technical solution solves the above problems.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A preparation process for fly ash specialized for concrete used in construction, comprising:

[0007] S1: Prepare the following raw materials in parts by weight: 100 - 1000 parts of fly ash, 3 - 30 parts of sodium chloride, 1 - 10 parts of modifier, 2 - 20 parts of surfactant, and 100 - 800 parts of distilled water;

[0008] S2: Mix the fly ash and sodium chloride, add distilled water, and stir evenly to obtain a preliminary mixed solution A;

[0009] S3: Add the modifier and surfactant to the preliminary mixed solution A, continue stirring at a stirring speed of 60 - 120 r / min for 30 - 60 minutes to obtain a composite mixed solution B;

[0010] S4: Subject the composite mixed solution B to airflow dispersion treatment at a temperature of 80 - 120 °C for 10 - 20 minutes to obtain a modified fly ash slurry;

[0011] S5: Separate the modified fly ash slurry through a centrifuge to obtain solid fly ash, and then conduct a drying treatment at a drying temperature of 70 - 100°C to obtain the final fly ash for construction.

[0012] Preferably, the specific amounts of raw materials in step S1 are: 500 parts of fly ash, 15 parts of sodium chloride, 5 parts of modifier, 10 parts of surfactant, and 400 parts of distilled water.

[0013] Preferably, the fly ash is high - activity fly ash containing 60% to 80% of silicon dioxide and aluminum, the modifier is a polymer with a high - molecular - chain structure, the surfactant is sodium dodecyl benzene sulfonate, the temperature of the air - flow dispersion treatment is 100°C, the treatment time is 15 minutes, and the particle size of fly ash in the obtained modified fly ash slurry is 1 - 5μm.

[0014] Preferably, the preparation process further includes a quality inspection step for the final product, including particle size distribution test, specific surface area test, fluidity test, and bond strength test. The bond strength test is carried out through standard mortar to evaluate the performance of fly ash.

[0015] Preferably, step S2 specifically includes:

[0016] Use a precision balance to weigh fly ash and sodium chloride to ensure that the ratio of fly ash to sodium chloride meets the formula requirements, and record the mass of raw materials.

[0017] Put the weighed fly ash and sodium chloride into a stirring container in the required ratio for dry mixing. Set the stirring speed to 30 - 50 r / min to ensure uniform mixing of the two, and the mixing time is 5 - 10 minutes.

[0018] Gradually add distilled water into the container, with the amount of water being 100 - 800 parts. During the addition process, keep the stirring speed at 30 - 50 r / min to ensure that the water is evenly distributed in the fly ash and sodium chloride mixture.

[0019] Continue to stir the mixture. The stirring time is 15 - 30 minutes to ensure complete fusion of fly ash, sodium chloride, and distilled water to form a uniform preliminary mixture A. During the stirring process, regularly check the appearance of the liquid to ensure that there is no particle aggregation or stratification.

[0020] Preferably, step S3 specifically includes:

[0021] Slowly add the weighed modifier and surfactant into the preliminary mixture A in portions to ensure uniform mixing after each addition.

[0022] After adding the modifier and surfactant to the primary mixture A, continue stirring at a speed of 60 - 120 r / min to ensure that the modifier and surfactant are completely dissolved and fully react with the fly ash and sodium chloride in the primary mixture A;

[0023] Keep the stirring time for 30 - 60 minutes, check the uniformity of the mixture during this period, and the speed can be adjusted appropriately during stirring to ensure that the modifier and surfactant can be fully mixed with the fly ash and sodium chloride to form a uniform composite mixture B;

[0024] During the stirring process, regularly observe the appearance of the composite mixture B to ensure that the liquid is uniform without obvious precipitation and stratification.

[0025] Preferably, the S4 specifically includes:

[0026] Slowly heat the composite mixture B to a temperature range of 80 - 120 °C and use a temperature control system to keep the temperature stable;

[0027] Disperse the composite mixture B by high-pressure air flow so that the fly ash particles in the composite mixture are quickly dispersed by the air flow, enhancing the surface modification effect;

[0028] During the air flow dispersion process, precisely control the speed, pressure and temperature of the air flow, and control the air flow pressure within the range of 0.2 - 0.5 MPa;

[0029] During the air flow dispersion process, continuously monitor the temperature and treatment time to ensure that the temperature is maintained between 80 - 120 °C and the treatment time is 10 - 20 minutes. Use a temperature sensor and a time control system to ensure the accuracy of the air flow dispersion;

[0030] Use an air flow dispersion tank to ensure that the dispersed fly ash particles are evenly distributed in the liquid;

[0031] During the air flow dispersion, continue stirring, and continuously monitor the temperature sensor and pressure gauge to observe the temperature and pressure changes during the air flow dispersion process;

[0032] After the air flow dispersion treatment is completed, collect the modified fly ash slurry and perform post-treatment.

[0033] Preferably, after the air flow dispersion treatment is completed, collecting the modified fly ash slurry and performing post-treatment specifically includes:

[0034] After the air flow dispersion treatment is completed, cool the modified fly ash slurry, use a cooling system or gradually reduce the temperature of the slurry to 20 - 30 °C to ensure the stability of the air pressure in the slurry during the cooling process;

[0035] Place the cooled slurry in a sedimentation container and let it stand still. Use the static method to allow the incompletely dispersed small particles to settle. The sedimentation time is 1 - 2 hours to ensure that the large particle fly ash in the slurry settles to the bottom of the container;

[0036] Through the layering phenomenon after sedimentation, manually pour out the supernatant and retain the precipitated part;

[0037] Transfer the sedimented slurry to a centrifuge for centrifugal separation. Set the rotational speed of the centrifuge within the range of 3000 - 5000 rpm and the centrifugation time for 10 - 15 minutes to further remove particulate impurities and obtain fly ash slurry.

[0038] Preferably, the S5 specifically includes:

[0039] Transfer the modified fly ash slurry after air dispersion treatment to the centrifuge tube of the centrifuge. Set the rotational speed and time of the centrifuge. The rotational speed of the centrifuge is set to 3000 - 5000 rpm and the centrifugation time is 10 - 15 minutes;

[0040] Under the action of centrifugal force, the solid fly ash particles in the slurry are pulled to the bottom of the tube, and the liquid part is separated to the upper layer. After centrifugal separation, collect the solid fly ash part at the bottom and separate the liquid in the upper layer;

[0041] Wash the solid fly ash obtained by centrifugal separation with deionized water to remove the residues attached to the surface of the solid fly ash;

[0042] Add the cleaning liquid to the fly ash, stir and let it stand still, and then separate it through a centrifuge to ensure the removal of impurities in the cleaning liquid;

[0043] Transfer the washed solid fly ash to a drying device for vacuum drying. Set the drying temperature between 70 - 100 °C and the drying time for 6 - 12 hours. Regularly check the temperature and humidity during the drying process.

[0044] Preferably, when the dried fly ash particles are uneven, perform a crushing treatment. Use a sieve to screen the dried fly ash to remove unqualified particles;

[0045] Pack the treated fly ash and store the packed fly ash in a dry warehouse.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] The fly ash modification process proposed by the present invention significantly improves the surface activity and reactivity of fly ash by adding additives such as sodium chloride, modifiers, and surfactants, and combining with air dispersion technology, enhancing the binding ability with concrete components. At the same time, the air dispersion technology effectively improves the dispersibility of fly ash, increases the contact area with the cement paste, thereby enhancing the overall performance of fly ash. The particle size distribution of the modified fly ash is more optimized, which can better react with cement, improve the strength and durability of concrete, especially showing significant effects on high-strength concrete. In addition, the modified fly ash has good fluidity and workability, improving the construction performance. This process is applicable to fly ash from different sources and compositions, especially showing significant effects on high-reactivity fly ash, with strong environmental protection and resource utilization advantages, meeting the requirements of sustainable development. The process is simple and easy to operate, with strong adaptability, ensuring the stability and quality of fly ash, and meeting the high standards of concrete projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a framework diagram of the step flow of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0049] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and other obvious variations can be thought of by those skilled in the art.

[0050] Refer to Figure 1 As shown, a preparation process for special fly ash for concrete used in construction includes:

[0051] S1: Prepare the following raw materials in parts by weight: 100 - 1000 parts of fly ash, 3 - 30 parts of sodium chloride, 1 - 10 parts of modifier, 2 - 20 parts of surfactant, and 100 - 800 parts of distilled water;

[0052] S2: Mix the fly ash and sodium chloride, add distilled water, and stir evenly to obtain the initial mixed liquid A;

[0053] S3: Add the modifier and surfactant to the initial mixed liquid A, continue to stir, the stirring speed is 60 - 120 r / min, and the stirring time is 30 - 60 minutes to obtain the composite mixed liquid B;

[0054] S4: Subject the composite mixed liquid B to air dispersion treatment at a temperature of 80 - 120 °C for 10 - 20 minutes to obtain the modified fly ash slurry;

[0055] S5: Separate the modified fly ash slurry by a centrifuge, obtain solid fly ash after separation, and then conduct drying treatment at a drying temperature of 70 - 100 °C to obtain the final fly ash for construction.

[0056] In step S1, the specific amounts of the raw materials are: 500 parts of fly ash, 15 parts of sodium chloride, 5 parts of modifier, 10 parts of surfactant, and 400 parts of distilled water.

[0057] The fly ash is highly reactive fly ash, containing 60% to 80% of silicon dioxide and aluminum. The modifier is a polymer with a high molecular chain structure. The surfactant is sodium dodecyl benzene sulfonate. The temperature of the air flow dispersion treatment is 100 °C, and the treatment time is 15 minutes. The particle size of the fly ash in the modified fly ash slurry obtained is 1 - 5 μm.

[0058] The preparation process also includes a quality inspection step for the final product, including particle size distribution test, specific surface area test, fluidity test, and bonding strength test. The bonding strength test is carried out through standard mortar to evaluate the performance of the fly ash.

[0059] S2 specifically includes:

[0060] Use a precision balance to weigh the fly ash and sodium chloride to ensure that the ratio of fly ash to sodium chloride meets the formula requirements, and record the mass of the raw materials.

[0061] Put the weighed fly ash and sodium chloride into a stirring container in the required ratio for dry mixing. Set the stirring speed at 30 - 50 r / min to ensure uniform mixing of the two, and the mixing time is 5 - 10 minutes.

[0062] Gradually add distilled water to the container, with the amount of water being 100 - 800 parts. During the addition process, keep the stirring speed at 30 - 50 r / min to ensure that the water is evenly distributed in the fly ash and sodium chloride mixture.

[0063] Continue to stir the mixture for 15 - 30 minutes to ensure that the fly ash, sodium chloride, and distilled water are completely fused to form a uniform preliminary mixture A. During the stirring process, regularly check the appearance of the liquid to ensure that there is no particle aggregation or stratification.

[0064] S3 specifically includes:

[0065] Slowly add the weighed modifier and surfactant to the preliminary mixture A in portions to ensure uniform mixing after each addition.

[0066] After adding the modifier and surfactant to the preliminary mixture A, continue to stir. Set the stirring speed at 60 - 120 r / min to ensure that the modifier and surfactant are completely dissolved and fully react with the fly ash and sodium chloride in the preliminary mixture A.

[0067] Keep the stirring time for 30 - 60 minutes. During this period, check the uniformity of the mixture. The speed can be appropriately adjusted during the stirring process to ensure that the modifier and surfactant can be completely mixed with the fly ash and sodium chloride to form a uniform composite mixture B.

[0068] During the stirring process, regularly observe the appearance of the composite mixture B to ensure that the liquid is uniform and there is no obvious precipitation or stratification.

[0069] S4 specifically includes:

[0070] Slowly heat the composite mixture B to a temperature range of 80 - 120 °C, and use a temperature control system to keep the temperature stable;

[0071] Disperse the composite mixture B by high-pressure air flow, so that the fly ash particles in the composite mixture are quickly dispersed by the air flow, enhancing its surface modification effect;

[0072] During the air flow dispersion process, precisely control the speed, pressure and temperature of the air flow, and control the pressure of the air flow within the range of 0.2 - 0.5 MPa;

[0073] During the air flow dispersion process, continuously monitor the temperature and treatment time to ensure that the temperature is maintained between 80 - 120 °C and the treatment time is 10 - 20 minutes, and use a temperature sensor and a time control system to ensure the accuracy of the air flow dispersion;

[0074] Use an air flow dispersion tank to ensure that the dispersed fly ash particles are evenly distributed in the liquid;

[0075] While carrying out the air flow dispersion, continue to stir, and continuously monitor the temperature sensor and the pressure gauge to observe the temperature and pressure changes during the air flow dispersion process;

[0076] After the air flow dispersion treatment is completed, collect the modified fly ash slurry and carry out post-treatment.

[0077] After the air flow dispersion treatment is completed, collecting the modified fly ash slurry and carrying out post-treatment specifically includes:

[0078] After the air flow dispersion treatment is completed, cool the modified fly ash slurry, use a cooling system or gradually reduce the temperature of the slurry to 20 - 30 °C to ensure the stability of the air pressure of the slurry during the cooling process;

[0079] Place the cooled slurry in a sedimentation container and let it stand still. Use the static method to let the small particles that are not completely dispersed settle. The sedimentation time is 1 - 2 hours to ensure that the large particle fly ash in the slurry settles to the bottom of the container;

[0080] Through the stratification phenomenon after sedimentation, manually pour out the supernatant liquid on the upper layer and retain the sediment part;

[0081] Transfer the sedimented slurry to a centrifuge for centrifugal separation. Set the rotation speed of the centrifuge within the range of 3000 - 5000 rpm and the centrifugation time is 10 - 15 minutes to further remove particle impurities and obtain fly ash slurry.

[0082] S5 specifically includes:

[0083] Transfer the modified fly ash slurry after airflow dispersion treatment to the centrifuge tube of the centrifuge, set the rotation speed and time of the centrifuge, the rotation speed of the centrifuge is set to 3000 - 5000 rpm, and the centrifugation time is 10 - 15 minutes;

[0084] Under the action of centrifugal force, the solid fly ash particles in the slurry are pulled to the bottom of the tube, and the liquid part is separated to the upper layer. After centrifugal separation, collect the solid fly ash part at the bottom and separate the liquid in the upper layer;

[0085] Wash the solid fly ash obtained by centrifugal separation with deionized water to remove the residues attached to the surface of the solid fly ash;

[0086] Add the cleaning liquid to the fly ash, stir and let it stand, and then separate it by a centrifuge to ensure the removal of impurities in the cleaning liquid;

[0087] Transfer the washed solid fly ash to a drying device for vacuum drying, set the drying temperature between 70 - 100 °C, the drying time is 6 - 12 hours, and regularly check the temperature and humidity during the drying process.

[0088] 10. A preparation process for special fly ash for concrete used in construction according to claim 9, characterized in that:

[0089] When the dried fly ash particles are uneven, perform crushing treatment, use a sieve to screen the dried fly ash, and remove unqualified particles;

[0090] Pack the processed fly ash and store the packaged fly ash in a dry warehouse

[0091] Example 1:

[0092] A preparation process for special fly ash for concrete used in construction, the preparation steps are as follows:

[0093] S1: Prepare the following amounts of raw materials: 500 parts of fly ash, 15 parts of sodium chloride, 5 parts of modifier, 10 parts of surfactant, and 400 parts of distilled water;

[0094] S2: Mix the fly ash and sodium chloride, add distilled water, and stir evenly to obtain a preliminary mixed solution A;

[0095] S3: Add the modifier and surfactant to the preliminary mixed solution A, continue to stir, the stirring speed is 90 r / min, and the stirring time is 45 minutes to obtain a composite mixed solution B;

[0096] S4: Subject the composite mixture B to air dispersion treatment at a temperature of 100 °C for 15 minutes to obtain a modified fly ash slurry;

[0097] S5: Separate the modified fly ash slurry by a centrifuge, and after separation, obtain solid fly ash, then conduct drying treatment at a drying temperature of 85 °C to obtain the final fly ash for construction.

[0098] Example 2:

[0099] A preparation process for fly ash special for concrete used in construction, and the preparation steps are as follows:

[0100] S1: Prepare the following amounts of raw materials: 300 parts of fly ash, 10 parts of sodium chloride, 3 parts of modifier, 5 parts of surfactant, and 250 parts of distilled water;

[0101] S2: Mix the fly ash and sodium chloride, add distilled water, and stir evenly to obtain a preliminary mixed liquid A;

[0102] S3: Add the modifier and surfactant to the preliminary mixed liquid A, and continue stirring at a stirring speed of 80 r / min for 35 minutes to obtain a composite mixture B;

[0103] S4: Subject the composite mixture B to air dispersion treatment at a temperature of 90 °C for 12 minutes to obtain a modified fly ash slurry;

[0104] S5: Separate the modified fly ash slurry by a centrifuge, and after separation, obtain solid fly ash, then conduct drying treatment at a drying temperature of 75 °C to obtain the final fly ash for construction.

[0105] Example 3:

[0106] A preparation process for fly ash special for concrete used in construction, and the preparation steps are as follows:

[0107] S1: Prepare the following amounts of raw materials: 800 parts of fly ash, 20 parts of sodium chloride, 8 parts of modifier, 15 parts of surfactant, and 700 parts of distilled water;

[0108] S2: Mix the fly ash and sodium chloride, add distilled water, and stir evenly to obtain a preliminary mixed liquid A;

[0109] S3: Add the modifier and surfactant to the preliminary mixed liquid A, and continue stirring at a stirring speed of 110 r / min for 50 minutes to obtain a composite mixture B;

[0110] S4: Subject the composite mixture B to air dispersion treatment at a temperature of 110 °C for 18 minutes to obtain a modified fly ash slurry;

[0111] S5: Separate the modified fly ash slurry through a centrifuge to obtain solid fly ash, and then conduct drying treatment at a drying temperature of 95°C to obtain the final fly ash for construction.

[0112] Comparative Example 1

[0113] The fly ash for construction prepared by the traditional method without using the method of the present invention, without using multi-component compounding and air flow dispersion treatment, has larger particle size, uneven particles, poor stability, easy moisture absorption, poor fluidity, and the actual application effect is inferior to that of Example 1, Example 2 and Example 3.

[0114] The following table is the property table of fly ash for construction prepared by different examples:

[0115]

[0116]

[0117] In summary, the advantages of the present invention are as follows:

[0118] The fly ash modification process provided by the present invention can effectively improve the surface activity of fly ash by adding additives such as sodium chloride, modifier and surfactant, and combining with air flow dispersion technology, so that its reactivity and bonding ability in concrete are significantly enhanced;

[0119] By using the air flow dispersion treatment technology, fly ash particles can be effectively dispersed into the slurry, increasing the contact area between fly ash and cement paste, thereby enhancing its reactivity with other components in concrete and improving the overall performance of fly ash;

[0120] By optimizing the particle size distribution and surface activity of fly ash, the modified fly ash can react better with cement, generate more hydration products, improve the strength and durability of concrete, especially for the use of high-strength concrete, and has a good effect;

[0121] The fly ash treated by the process of the present invention has good fluidity and workability, making it perform more excellently in the concrete mixing and construction process, and reducing the construction difficulty caused by rough or unevenly dispersed fly ash particles;

[0122] This process is applicable to fly ash from different sources and compositions, especially for high-reactivity fly ash, and has a significant modification effect, so it can be used in a variety of construction environments;

[0123] The process of the present invention utilizes the industrial by-product fly ash and improves its performance through modification treatment, which not only solves the problem of waste treatment but also enhances the resource utilization efficiency, meeting the requirements of sustainable development. The process steps are simple and easy to operate, and can be adjusted according to different production requirements, having high industrial application value and economic benefits;

[0124] Through precise control of each step and strict quality inspection, it is ensured that the finally obtained fly ash for construction has uniform particle size and stable quality, meeting the high-standard requirements of concrete projects.

[0125] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection required by the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation process for special fly ash for concrete used in construction, characterized in that, Including: S1: Prepare raw materials in the following amounts: 100 - 1000 parts of fly ash, 3 - 30 parts of sodium chloride, 1 - 10 parts of modifier, 2 - 20 parts of surfactant, and 100 - 800 parts of distilled water; S2: Mix the fly ash and sodium chloride, add distilled water, and stir evenly to obtain a preliminary mixed solution A; S3: Add the modifier and surfactant to the preliminary mixed solution A, continue stirring, with a stirring speed of 60 - 120 r / min and a stirring time of 30 - 60 minutes to obtain a composite mixed solution B; S4: Subject the composite mixed solution B to gas - flow dispersion treatment at a temperature of 80 - 120 °C for 10 - 20 minutes to obtain a modified fly ash slurry; S5: Separate the modified fly ash slurry by a centrifuge, obtain solid fly ash after separation, and then conduct drying treatment at a drying temperature of 70 - 100 °C to obtain the final fly ash for construction.

2. The preparation process of a special fly ash for concrete used in construction according to claim 1, characterized in that: In step S1, the raw materials in specific amounts are: 500 parts of fly ash, 15 parts of sodium chloride, 5 parts of modifier, 10 parts of surfactant, and 400 parts of distilled water.

3. The preparation process of a special fly ash for concrete used in construction according to claim 2, characterized in that: The fly ash is high - activity fly ash, containing 60% to 80% of silicon dioxide and aluminum. The modifier is a polymer with a high - molecular - chain structure. The surfactant is sodium dodecyl benzene sulfonate. The temperature of the gas - flow dispersion treatment is 100 °C, and the treatment time is 15 minutes. The particle size of fly ash in the obtained modified fly ash slurry is 1 - 5 μm.

4. The preparation process of a special fly ash for concrete used in construction according to claim 3, characterized in that, The preparation process also includes a quality inspection step for the final product, including particle - size distribution test, specific surface area test, fluidity test, and bond strength test. The bond strength test is carried out through standard mortar to evaluate the performance of fly ash.

5. The preparation process of a special fly ash for concrete used in construction according to claim 4, characterized in that, The specific content of S2 includes: Use a precision balance to weigh the fly ash and sodium chloride, ensure that the ratio of fly ash to sodium chloride meets the formula requirements, and record the raw material quality; Put the weighed fly ash and sodium chloride into a stirring container according to the required ratio for dry mixing, set the stirring speed at 30 - 50 r / min, ensure uniform mixing of the two, and the mixing time is 5 - 10 minutes; Gradually add distilled water to the container, with the water volume being 100 - 800 parts. During the addition process, keep the stirring speed at 30 - 50 r / min to ensure that the water is evenly distributed in the fly ash and sodium chloride mixture; Continue to stir the mixed solution for 15 - 30 minutes to ensure complete fusion of fly ash, sodium chloride, and distilled water to form a uniform preliminary mixed solution A. During the stirring process, regularly check the appearance of the liquid to ensure that there is no particle aggregation and stratification phenomenon.

6. The preparation process of a special fly ash for concrete used in construction according to claim 5, characterized in that, The specific content of S3 includes: Slowly add the weighed modifier and surfactant to the preliminary mixed solution A in portions to ensure uniform mixing after each addition; After adding the modifier and surfactant to the preliminary mixed solution A, continue stirring, set the stirring speed at 60 - 120 r / min, and ensure that the modifier and surfactant are completely dissolved and fully react with the fly ash and sodium chloride in the preliminary mixed solution A; Keep the stirring time at 30 - 60 minutes. During this period, check the uniformity of the mixed solution. The speed can be appropriately adjusted during the stirring process to ensure that the modifier and surfactant can be fully mixed with fly ash and sodium chloride to form a uniform composite mixed solution B. During the stirring process, regularly observe the appearance of the composite mixed solution B to ensure that the liquid is uniform and there is no obvious precipitation and stratification.

7. The preparation process of a special fly ash for concrete used in construction according to claim 6, characterized in that, The specific steps of S4 are as follows: Slowly heat the composite mixed solution B to a temperature range of 80 - 120 °C, and use a temperature control system to keep the temperature stable. Disperse the composite mixed solution B by high-pressure air flow, so that the fly ash particles in the composite mixed solution can be quickly dispersed by the air flow, enhancing the surface modification effect. During the air flow dispersion process, the speed, pressure, and temperature of the air flow are precisely regulated, and the pressure of the air flow is controlled within the range of 0.2 - 0.5 MPa. During the air flow dispersion process, continuously monitor the temperature and treatment time to ensure that the temperature is maintained between 80 - 120 °C and the treatment time is 10 - 20 minutes. Use a temperature sensor and a time control system to ensure the accuracy of the air flow dispersion. Use an air flow dispersion tank to ensure that the dispersed fly ash particles are evenly distributed in the liquid. During the air flow dispersion, continue to stir, and continuously monitor the temperature sensor and the pressure gauge to observe the temperature and pressure changes during the air flow dispersion process. After the air flow dispersion treatment is completed, collect the modified fly ash slurry and perform post-treatment.

8. The preparation process of a special fly ash for concrete used in construction according to claim 7, characterized in that, The specific steps of collecting the modified fly ash slurry and performing post-treatment after the air flow dispersion treatment are as follows: After the air flow dispersion treatment is completed, cool the modified fly ash slurry. Use a cooling system or gradually reduce the temperature of the slurry to 20 - 30 °C to ensure the stability of the air pressure in the slurry during the cooling process. Place the cooled slurry in a sedimentation container and let it stand still. Use the static method to let the small particles that are not fully dispersed settle. The sedimentation time is 1 - 2 hours to ensure that the large particle fly ash in the slurry settles to the bottom of the container. Through the layering phenomenon after sedimentation, manually pour out the upper clear liquid and retain the sediment part. Transfer the sedimented slurry to a centrifuge for centrifugal separation. Set the rotation speed of the centrifuge within the range of 3000 - 5000 rpm, and the centrifugation time is 10 - 15 minutes to further remove particle impurities and obtain fly ash slurry.

9. The preparation process of a special fly ash for concrete used in construction according to claim 8, characterized in that, The specific steps of S5 are as follows: Transfer the modified fly ash slurry after the air flow dispersion treatment to the centrifuge tube of the centrifuge, and set the rotation speed and time of the centrifuge. The rotation speed of the centrifuge is set to 3000 - 5000 rpm, and the centrifugation time is 10 - 15 minutes. Under the action of centrifugal force, the solid fly ash particles in the slurry are pulled to the bottom of the tube, and the liquid part is separated to the upper layer. After centrifugal separation, collect the solid fly ash part at the bottom and separate the upper layer of liquid. Wash the solid fly ash obtained by centrifugal separation with deionized water to remove the residues attached to the surface of the solid fly ash. Add the washing liquid to the fly ash, stir and let it stand still, and then separate it by a centrifuge to ensure the removal of impurities in the washing liquid. Transfer the cleaned solid fly ash to a drying equipment for vacuum drying. Set the drying temperature between 70 - 100 °C and the drying time for 6 - 12 hours. Regularly check the temperature and humidity during the drying process.

10. The preparation process of a special fly ash for concrete used in construction according to claim 9, characterized in that: When the dried fly ash particles are uneven, perform a crushing treatment. Use a sieve to screen the dried fly ash and remove the unqualified particles; Package the treated fly ash and store the packaged fly ash in a dry warehouse.

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