Method for repairing chimney of granulation tower after acid erosion

Abstract

The invention discloses a repairing method for a chimney of a granulation tower after acid erosion, and relates to the technical field of steelmaking. According to the method, drilling and bar planting are conducted on the inner wall of the chimney of the granulation tower, a reinforcing mesh is fixed, then a concrete interface agent is sprayed, and then a gunning material with specific components is sprayed. New concrete and old concrete are firmly combined through the concrete interface agent, and the layering isolation phenomenon is avoided; the gunning material formed by the composite powder and the water glass solution can comprehensively repair damage caused by acid erosion, effectively ensure the structural integrity and stability of the chimney, remarkably improve the acid erosion resistance of the chimney and prolong the service life of the chimney. The whole repairing process is simple and easy to implement, the construction period is short, the influence on production is small, and the cost benefit is more prominent.

Description

Technical Field

[0001] The invention relates to the technical field of steelmaking, in particular to a method for repairing a granulating tower chimney after acid corrosion. Background Art

[0002] In the ironmaking slag treatment process, the water slag granulation tank is designed as a concrete structure. For example, the chimney height is about 80 meters, the lower inner diameter is about 6 meters, the upper inner diameter is about 3 meters, and the wall thickness of the barrel is 400-160mm from bottom to top, and the height is stepped. In the process of water flushing high-temperature hot slag, acidic gases and substances are generated, which will cause continuous erosion to the chimney at the bottom of the granulation tower.

[0003] When chimneys are eroded, they need to be repaired. Traditional repair methods have many limitations in dealing with this problem. Specifically, they can be roughly divided into the following three repair methods:

[0004] (1) Surface coating method, usually using ordinary anti-corrosion paint directly coated on the inner wall of the chimney. The protective effect of this method is limited, the coating is easy to peel off in a short time, and it cannot effectively resist the long-term corrosion of acidic substances. In addition, the adhesion between the coating and the chimney surface is weak, and it is easy to fall off under temperature changes and airflow impact.

[0005] (2) Local repair method: a separate coating is applied to the obvious corroded and damaged area. This method often only treats the surface symptoms and cannot solve the corrosion problem of the overall structure, which can easily lead to aggravated corrosion of other unrepaired parts. Moreover, the material after local repair is less compatible with the original structure and cannot effectively solve the overall structural stability.

[0006] (3) Overall secondary pouring method: For severely corroded lower chimneys, overall secondary pouring is performed and the pouring thickness should be appropriately increased by 50 to 100 mm. This is a more thorough solution, but it is costly, has a long construction period, and has a significant impact on production.

[0007] In summary, the current traditional chimney repair methods have the following problems: (1) they cannot guarantee the structural integrity and stability of the chimney; (2) they cannot significantly improve the chimney's resistance to acid corrosion; and (3) the construction period is long and the cost is high.

[0008] In view of this, the present invention is proposed. Summary of the invention

[0009] The purpose of the present invention is to provide a method for repairing a granulation tower chimney after acid corrosion, aiming to provide a repair method with a short construction period, which can effectively ensure the structural integrity and stability of the chimney and improve the chimney's resistance to acid corrosion.

[0010] The present invention is achieved in that:

[0011] In a first aspect, the present invention provides a method for repairing a granulation tower chimney after acid corrosion, comprising:

[0012] Drill holes on the inner wall of the granulation tower chimney to plant reinforcement and fix the steel mesh, then spray the concrete interface agent and then spray the gunning material;

[0013] The preparation process of the gunning material includes: mixing the composite powder and the water glass solution, the mass ratio of the water glass solution to the composite powder is (5-30):100, and the composite powder contains aluminum oxide and silicon oxide.

[0014] In an optional embodiment, the mass ratio of the water glass solution to the composite powder is (15-25):100;

[0015] Preferably, the mass ratio of the water glass solution to the composite powder is 20:100.

[0016] In an optional embodiment, in the composite powder, the mass fraction of aluminum oxide is 48%-55%, and the mass fraction of silicon oxide is 35%-42%;

[0017] Preferably, the preparation process of the composite powder includes: mixing low-iron high-aluminum aggregate powder, silica-aluminum powder, aluminate cement, high-efficiency water reducer and dispersant, so that the mass fraction of alumina and silica meets the requirements;

[0018] Preferably, the particle size of the composite powder is ≤75 μm.

[0019] In an optional embodiment, the solid content of the water glass solution is 35%-45%.

[0020] In an optional embodiment, the spraying thickness of the gunning material is controlled to be 60 mm-100 mm;

[0021] Preferably, a high-pressure pulse gunning machine is used for spraying, and the gunning is controlled to be performed step by step in a spiral ascending manner.

[0022] In an optional embodiment, after the spraying of the repairing material, natural curing is performed for more than 48 hours.

[0023] In an optional embodiment, before drilling holes and planting reinforcement bars, the inner wall of the granulation tower chimney is cleaned first.

[0024] In an optional embodiment, the cleaning process includes: using a high-pressure water gun to clean the inner wall of the chimney to remove corrosion products and dust.

[0025] In an optional embodiment, the process of drilling and embedding reinforcement includes: drilling holes on the inner wall of the chimney, controlling the hole diameter to be 10mm-15mm, the hole depth to be 100mm-150mm, and the distance between adjacent holes to be 240mm-260mm; after the drilling is completed, cleaning the holes and filling them with structural glue, the amount of glue filling being based on the glue overflowing after the steel bar is inserted; inserting the anchor steel bar into the hole by 70mm-90mm, exposing 35mm-45mm, and making a right-angle hook in an upward direction;

[0026] Among them, the difference between the diameter of the anchor steel bar and the hole diameter is 1mm-3mm.

[0027] In an optional embodiment, the process of fixing the steel mesh includes: using steel bars with a diameter of 5mm-7mm to make the steel mesh, the mesh is rectangular, the length is 150mm-250mm, and the width is 150mm-250mm; hanging the steel mesh on the anchoring steel bars and fixing it.

[0028] The present invention has the following beneficial effects: the present invention drills holes on the inner wall of the granulation tower chimney to plant steel bars, fixes the steel mesh, sprays the concrete interface agent, and then sprays the gunning material of a specific composition. The concrete interface agent is used to firmly combine the new and old concretes without stratification and isolation; the gunning material formed by the composite powder and the water glass solution can fully repair the damage caused by acid corrosion, effectively ensure the structural integrity and stability of the chimney, significantly improve the chimney's ability to resist acid corrosion, and extend its service life. The entire repair process is simple and easy, with a short construction period, less impact on production, and more outstanding cost-effectiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 Schematic diagram of the inner surface of the lower part of the chimney body after acid corrosion; (a), (b), and (c) represent different areas of the lower part of the body;

[0031] Figure 2 Schematic diagram of the inner surface of the middle and upper part of the chimney body after acid corrosion; (a) and (b) represent different areas of the middle and upper part of the body;

[0032] Figure 3 A flowchart of a repair method is provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0034] The inner surface of the granulation tower chimney after corrosion is as follows Figure 1 and Figure 2 As shown in the figure, the inner surface of the chimney body has steel bar surface (partially exposed steel bar). In order to find a more targeted repair method, the inventor analyzed the causes of the above problems:

[0035] The structure type of the granulation tower is a reinforced concrete structure, and the concrete structure is a strong block structure formed by mixing, solidifying and bonding four materials: cement, crushed stone, sand and water. Cement, as a bonding material for concrete structure, is alkaline in itself, and its chemical properties are alkali-resistant but not acid-resistant. The crushed stone in the concrete structure has a softening effect when it comes into contact with water. The flue gas emitted by the granulation tower contains acidic water vapor, and at the same time carries a small amount of dust particles, and has a certain flow rate. The concrete structure of the chimney is infiltrated by water vapor for a long time during use and is in a humid state. The strength of the concrete on the inner surface is reduced due to the softening effect; under the action of acidic water vapor, the alkalinity of the cement is neutralized and loses its bonding ability, and the concrete on the inner surface becomes loose; under the scouring action of the flue gas carrying dust particles, the concrete on the inner surface of the chimney peels off and becomes a rough surface. As a result, the protective layer of the steel bar has been worn through, reaching the state of the steel bar surface (partially exposed steel bars).

[0036] The granulated tower concrete chimney is a load-bearing structure composed of two layers of steel bars and concrete. The continued wear of the chimney inner wall will lead to the damage of the inner steel bars. When a large area of ​​steel bars are damaged, the chimney structure will have the safety problem of instability and collapse due to reduced structural strength.

[0037] In view of the above analysis, the embodiment of the present invention provides a method for repairing a granulation tower chimney after acid corrosion, which uses an acidic spraying material for repair. By forming a protection between the inner wall of the original chimney structure and preventing further damage from acidic water vapor, the chimney structure strength can be ensured to be safe and stable. Figure 3 The specific steps of the repair method are as follows:

[0038] S1. Surface treatment

[0039] Before spraying the gunning material, the inner wall of the granulation tower chimney is surface treated. The specific steps of surface treatment include cleaning, drilling and planting steel bars, fixing steel mesh, and spraying concrete interface agent. The following is a description of each step:

[0040] S11. Cleaning

[0041] Use a high-pressure water gun to thoroughly clean the inner wall of the granulation tower chimney to remove stubborn corrosion products and dust to prevent these substances from affecting the firmness of the bond between the new and old concrete.

[0042] S12, drilling and planting steel bars, fixing steel mesh

[0043] Drill holes on the inner wall of the granulation tower chimney, plant reinforcement and fix the steel mesh to lay the foundation for forming a new concrete structure.

[0044] In some embodiments, the process of drilling and planting steel bars includes: drilling holes on the inner wall of the chimney, controlling the hole diameter to be 10mm-15mm, the hole depth to be 100mm-150mm, and the spacing between adjacent holes to be 240mm-260mm; after the drilling is completed, cleaning the dust in the hole and filling it with structural glue, the amount of glue filling being based on the glue overflowing after the steel bar is inserted; then inserting the anchor steel bar into the hole 70mm-90mm, exposing 35mm-45mm, and making a right-angle hook in an upward direction to fix the steel mesh. Among them, the difference between the diameter of the anchor steel bar and the hole diameter is 1mm-3mm, that is, the diameter of the anchor steel bar is slightly smaller than the hole diameter.

[0045] Specifically, the hole diameter can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc.; the hole depth can be 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, etc., and the distance between adjacent holes can be 240mm, 250mm, 260mm, etc. After the drilling is completed, the dust in the pores is cleaned and filled with structural adhesive. The structural adhesive is a commercially available material (generally containing a resin base material, a curing agent, a filler, etc.), such as Sika, which can be purchased from Swiss Sika Company, model Sikadur35. The length of the anchoring steel bar can be about 10mm, the length inserted into the hole can be 70mm, 80mm, 90mm, etc., and the exposed length can be 35mm, 40mm, 45mm, etc. The length of the right-angle hook can be 15mm-25mm, such as 15mm, 20mm, 25mm, etc.

[0046] In some embodiments, the process of fixing the steel mesh includes: using steel bars with a diameter of 5mm-7mm to make the steel mesh, the mesh is rectangular, the length is 150mm-250mm, and the width is 150mm-250mm; hanging the steel mesh on the anchoring steel bars and fixing it.

[0047] Specifically, the diameter of the steel bars used to make the steel mesh can be 5mm, 6mm, 7mm, etc., and the length and width of the mesh can be independently 150mm, 200mm, 250mm, etc. The steel mesh is hung on the anchoring steel bars and connected and fixed by spot welding or tying. The size of the mesh is determined according to the convenience of on-site construction, and the meshes are connected by tying or welding.

[0048] S13, spraying concrete interface agent

[0049] Before spraying the repair material, spraying a layer of concrete interface agent can make the new and old concrete bond firmly and avoid stratification and isolation.

[0050] Specifically, the concrete interface agent is a commercially available raw material, mainly containing polymer emulsion, cement, filler, additives, etc., such as the one that can be purchased from Sankeshu Company, model SG-600 waterproof interface agent.

[0051] S2. Spraying and repairing materials

[0052] After the surface treatment, a specific composition of the gunning material is sprayed. The preparation process of the gunning material includes: mixing a composite powder and a water glass solution, the mass ratio of the water glass solution to the composite powder is (5-30):100, and the composite powder contains aluminum oxide and silicon oxide. The inventors have optimized the composition and proportion of the gunning material to improve the mechanical properties and corrosion resistance of the material. A layer of acid-resistant and wear-resistant protective lining is sprayed on the inner wall of the chimney to form a protection between the inner wall of the original chimney structure, which is not further damaged by acidic water vapor, ensuring the safety and stability of the chimney structure strength.

[0053] Specifically, the mass ratio of the water glass solution to the composite powder can be 5:100, 10:100, 15:100, 20:100, 25:100, 30:100, etc.

[0054] In a preferred embodiment, the mass ratio of the water glass solution to the composite powder is (15-25): 100, and more preferably 20: 100. By optimizing the mass ratio of the water glass solution to the composite powder, the mechanical properties and corrosion resistance of the material can be further improved.

[0055] In some embodiments, in the composite powder, the mass fraction of aluminum oxide is 48%-55% (such as 48%, 50%, 53%, 55%, etc.), and the mass fraction of silicon oxide is 35%-42% (such as 35%, 38%, 40%, 42%, etc.). The ratio of aluminum oxide to silicon oxide in the composite powder is preferably within the above range, which is conducive to further improving the repair effect, significantly improving the acid corrosion resistance of the chimney, and extending its service life. The particle size of the composite powder is ≤75μm, and the particle size of the composite powder should not be too large, otherwise it will affect the uniformity of the repair layer and affect the integrity and stability of the chimney structure.

[0056] In some embodiments, the preparation process of the composite powder includes: mixing low-iron high-aluminum aggregate powder, silica-aluminum powder, aluminate cement, high-efficiency water reducer and dispersant, so that the content of alumina and silica after mixing meets the requirements. Among them, low-iron high-aluminum aggregate powder was purchased from Gongyi Tongda Refractory Material Co., Ltd., model TD-85A; silica-aluminum powder was purchased from Wuxi Tainuo Refractory Material Co., Ltd., model TN-SF92; aluminate cement was purchased from the conventional product model CA-70 on the market; high-efficiency water reducer was purchased from Shandong Longkou Shuanglong Chemical Co., Ltd., model SL-FDN; dispersant was selected from Wuhan Green Lin Co., Ltd. GRL-P04 model. The mass ratio of low-iron and high-aluminum aggregate powder, silica-aluminum powder, aluminate cement, high-efficiency water reducer and dispersant can be (60-70): (25-30): (5.5-6.0): (0.5-1.0): (0.3-0.8), such as 65%: 28%: 5.7%: 0.8%: 0.5%.

[0057] In some embodiments, the solid content of the water glass solution is 35%-45%, such as 35%, 40%, 45%, etc. The water glass solution can be a commercially available material, the modulus can be 3.2, and the solid content is 40%. Specifically, the water glass solution can be purchased from Jiaxing Kaisheng New Material Technology Co., Ltd., model KS-40.

[0058] In some embodiments, the spraying thickness of the spraying material is controlled to be 60 mm-100 mm, such as 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, etc.

[0059] In some embodiments, a high-pressure pulse gunning machine is used for spraying, which can achieve precise material spraying control and ensure the uniformity and density of the gunning layer. The multi-axis linkage spray gun can flexibly adjust the spraying angle and distance to adapt to the complex structure inside the chimney. Connecting an efficient compressed air system and material delivery pipeline ensures the continuity and stability of the gunning process.

[0060] In actual operation, the prepared gunning material is loaded into the hopper of the gunning machine, and the injection pressure and flow rate of the material are adjusted according to the damage and corrosion degree of the chimney inner wall. The operator wears protective equipment and starts from the bottom of the chimney with a handheld spray gun, and gradually performs gunning in a spiral ascending manner. The total gunning thickness is controlled at 60-100mm to ensure that the material is evenly distributed and free of voids and bubbles. During the gunning process, the thickness and quality of the gunning layer are monitored in real time. If there are uneven or defective parts, they are promptly re-sprayed.

[0061] S3. Maintenance and inspection

[0062] After spraying the repair material, it should be naturally cured for more than 48 hours to form a stable concrete structure. During this period, appropriate protective measures should be taken to avoid interference from external factors in the curing process.

[0063] The repaired chimney inner wall is fully inspected using non-destructive testing techniques such as ultrasonic testing, X-ray testing and magnetic particle testing, with a focus on checking the thickness, uniformity, bonding strength and presence of internal defects of the sprayed patch layer.

[0064] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0065] Example 1

[0066] This embodiment provides a method for repairing a granulation tower chimney after acid corrosion, the steps are as follows:

[0067] (1) Surface treatment

[0068] Use a high-pressure water gun to thoroughly clean the inner wall of the chimney.

[0069] Drill holes on the inner wall of the chimney with a diameter of 12mm and a depth of 110mm. The spacing between adjacent holes is 250mm. After cleaning the holes, fill them with structural glue. The amount of glue filled is based on the glue overflow after inserting the steel bars. The anchor steel bar is Φ10mm, inserted into the hole for 10cm, exposed 40mm, and a 20mm long right-angle hook is made in the upward direction. Use Φ6mm steel bars to make steel mesh with a mesh spacing of 200*200mm. Hang the steel mesh on the anchor steel bar and connect and fix it by spot welding. The size of the mesh is determined according to the convenience of on-site construction, and the meshes are connected by welding.

[0070] Before spraying the repair material, spray a layer of concrete interface agent.

[0071] (2) Spraying and repairing materials

[0072] Preparation of gunning material: Mix the composite powder (Al2O3-SiO2 composite powder) and water glass solution, the mass ratio of water glass solution to composite powder is 20:100. The composite powder contains aluminum oxide and silicon oxide, the mass fraction of aluminum oxide is 48%-55%, and the mass fraction of silicon oxide is 35%-42%. The modulus of the water glass solution is 3.2, and the solid content is 40%.

[0073] Load the prepared gunning material into the hopper of the high-pressure pulse gunning machine. The operator wears protective equipment and starts from the bottom of the chimney with a spray gun, and gradually guns up in a spiral manner. The total gunning thickness is controlled at about 80mm. During the gunning process, the thickness and quality of the gunning layer are monitored in real time. If there are uneven or defective parts, re-spray them in time.

[0074] (3) Maintenance and inspection

[0075] After the spraying is completed, the natural curing time is 50 hours, and ultrasonic testing is used to check whether the thickness, uniformity and bonding strength meet the requirements.

[0076] Example 2

[0077] The only difference from Example 1 is that during the preparation of the gunning material, the mass ratio of the water glass solution to the composite powder is controlled to be 5:100.

[0078] Example 3

[0079] The only difference from Example 1 is that during the preparation of the gunning material, the mass ratio of the water glass solution to the composite powder is controlled to be 10:100.

[0080] Example 4

[0081] The only difference from Example 1 is that during the preparation of the gunning material, the mass ratio of the water glass solution to the composite powder is controlled to be 15:100.

[0082] Example 5

[0083] The only difference from Example 1 is that during the preparation of the gunning material, the mass ratio of the water glass solution to the composite powder is controlled to be 25:100.

[0084] Example 6

[0085] The only difference from Example 1 is that during the preparation of the gunning material, the mass ratio of the water glass solution to the composite powder is controlled to be 30:100.

[0086] Comparative Example 1

[0087] The only difference from Example 1 is that the spraying material is CL-130G, which has poor curing resulting in decreased adhesion, easy peeling and cracking of the coating, reduced acid resistance, accelerated corrosion of the substrate due to water vapor penetration, and significantly deteriorated protective effect.

[0088] Test Example 1

[0089] The performance of the gunning materials provided in the examples and comparative examples was tested, and the results are shown in Table 1.

[0090] Test methods: (1) Compressive strength: GB / T 17671-1999 standard test block test after curing; (2) Flexural strength: Three-point bending method test 100×20×10mm specimen; (3) Acid resistance: Determine the mass loss rate and strength retention rate after immersion in 20% nitric acid solution for 72 hours.

[0091] Table 1 Performance test results of the gunning materials provided in the embodiments and comparative examples

[0092]

[0093] It can be seen that with the increase of water glass doping, the strength characteristics show a trend of first rising and then falling, reaching a peak value at 20% doping (compression resistance 16.1MPa, flexural resistance 3.9MPa); the acid resistance index is positively correlated with the doping, but after exceeding 20%, the performance declines due to the decrease in structural density; microscopic analysis shows that: a continuous silicate network structure is formed at a doping of 20%, and the porosity is the lowest. Therefore, the 20% water glass doping sample has the best comprehensive performance and is particularly suitable for anti-corrosion lining applications under acidic gas in ironmaking granulation towers. The developed material has acid resistance, strong adhesion, and a certain degree of wear resistance.

[0094] Test Example 2

[0095] The gunning material was made into a sample according to Example 1, placed in a 20% nitric acid solution, soaked at 80 degrees for 72 hours and then dried at 110 degrees, as shown in Table 2.

[0096] Table 2 Acid bubble test results

[0097] project unit index Chemical composition (%) <![CDATA[Al2O3]]> ≥30 Bulk density (after baking at 110℃×24h) <![CDATA[g / cm 2 ]]> ≥1.80 Flexural strength (after baking at 110℃×24h) MPa ≥3 Compressive strength (after baking at 110℃×24h) MPa ≥15 Flexural strength (after burning at 1000℃×3h) MPa ≥4 Linear change rate after firing (1000℃×3h) ％ ±0.5 Liquid binder ％ 20-22

[0098] After testing: the strength of the flexural strength is 3.7MPa, and the pressure resistance is 16MPa. The overall acid resistance is qualified, and the strength decreases slightly. The pH value of the sample residue damaged by acid bubbles is still weakly alkaline 8-9 when soaked in water.

[0099] Test Example 3

[0100] The test examples and comparative examples provide the repair effect of the repair method. The spraying material is CL-130G, which has poor curing resulting in decreased adhesion, easy peeling and cracking of the coating, reduced acid resistance, accelerated corrosion of the substrate due to water vapor penetration, and significantly deteriorated protective effect.

[0101] In summary, the present invention provides a method for repairing a granulation tower chimney after acid corrosion. By optimizing the repair process and spraying materials, it has the following advantages: (1) The spraying method can completely repair the damage caused by acid corrosion and effectively ensure the structural integrity and stability of the chimney. (2) The combination of the selected special materials and the advanced spraying process can form a strong and durable protective layer, which significantly improves the chimney's resistance to acid corrosion and extends its service life. (3) Compared with traditional repair methods, this method has a short construction period, less impact on production, and more outstanding cost-effectiveness. (4) Regular inspection and maintenance can promptly detect potential problems and ensure the safety and reliability of the chimney during long-term operation.

[0102] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for repairing a granulation tower chimney after acid corrosion, characterized in that: include: Drill holes on the inner wall of the granulation tower chimney to plant reinforcement and fix the steel mesh, then spray the concrete interface agent and then spray the gunning material; The preparation process of the gunning material includes: mixing composite powder and water glass solution, the mass ratio of the water glass solution to the composite powder is (5-30):100, and the composite powder contains aluminum oxide and silicon oxide.

2. The repair method according to claim 1, characterized in that: The mass ratio of the water glass solution to the composite powder is (15-25):100; Preferably, the mass ratio of the water glass solution to the composite powder is 20:

100.

3. The repair method according to claim 1, characterized in that: In the composite powder, the mass fraction of aluminum oxide is 48%-55%, and the mass fraction of silicon oxide is 35%-42%; Preferably, the preparation process of the composite powder comprises: mixing low-iron high-aluminum aggregate powder, silica-aluminum powder, aluminate cement, high-efficiency water reducer and dispersant, so that the mass fraction of alumina and silica meets the requirements; Preferably, the particle size of the composite powder is ≤75 μm.

4. The repair method according to claim 1, characterized in that: The solid content of the water glass solution is 35%-45%.

5. The repair method according to any one of claims 1 to 4, characterized in that: Controlling the spraying thickness of the gunning material to be 60mm-100mm; Preferably, a high-pressure pulse gunning machine is used for spraying, and the gunning is controlled to be performed step by step in a spiral ascending manner.

6. The repair method according to claim 5, characterized in that: After spraying the repair material, natural curing is performed for more than 48 hours.

7. The repair method according to claim 1, characterized in that: Before drilling holes and planting reinforcement bars, the inner wall of the granulating tower chimney is cleaned first.

8. The repair method according to claim 7, characterized in that: The cleaning process includes: using a high-pressure water gun to clean the inner wall of the chimney to remove corrosion products and dust.

9. The repair method according to claim 1, characterized in that: The process of drilling and embedding reinforcement includes: drilling holes on the inner wall of the chimney, controlling the hole diameter to be 10mm-15mm, the hole depth to be 100mm-150mm, and the distance between adjacent holes to be 240mm-260mm; after the drilling is completed, cleaning the holes and filling them with structural glue, the amount of glue filling being based on the glue overflowing after the steel bar is inserted; inserting the anchor steel bar into the hole by 70mm-90mm, exposing 35mm-45mm, and making a right-angle hook in an upward direction; The difference between the diameter of the anchor steel bar and the hole diameter is 1mm-3mm.

10. The repair method according to claim 9, characterized in that: The process of fixing the steel mesh includes: using steel bars with a diameter of 5mm-7mm to make the steel mesh, the mesh is rectangular, the length is 150mm-250mm, and the width is 150mm-250mm; hanging the steel mesh on the anchoring steel bars and fixing it.

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