A castable for preventing corrosion of incineration waste gas on inner wall of incinerator and a preparation method thereof

Abstract

This invention relates to the field of refractory materials technology, specifically to a castable refractory for preventing corrosion of the inner wall of an incinerator by incineration exhaust gas and its preparation method. The castable refractory, by weight, comprises: 65-75 parts composite aggregate, 8-10 parts corrosion-resistant latex, 1-2 parts binder, 3-5 parts aluminum powder paste, 1-3 parts expanded perlite, and 2-3 parts glass fiber. The preparation method includes the following steps: S1, aggregate premixing; S2, powder premixing; S3, casting; S4, post-treatment. This invention solves the problems of existing acidic castables being unresistant to alkalis, easily becoming brittle and losing their corrosion resistance in humid environments, by preparing a corrosion-resistant latex that significantly improves the corrosion resistance of the castable refractory and also provides waterproofing. Simultaneously, the addition of this corrosion-resistant latex effectively improves the overall strength and stability of the castable refractory, thus improving its performance.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, specifically to a castable refractory and its preparation method for preventing corrosion of the inner wall of an incinerator by combustion exhaust gas. Background Technology

[0002] Castable refractory refers to refractory materials used to make the linings of various cement kilns and incinerators. Due to the large amount of acidic, alkaline and salt spray-type exhaust gases generated during the incineration process, the castable refractory for the inner wall of the incinerator currently has limited corrosion resistance in daily use, which causes the exhaust gases to corrode the metal cylinder of the incinerator inner wall, greatly shortening the service life of the rotary kiln.

[0003] The main components of castable refractory materials include stone, metallic or non-metallic compounds, and binders. Existing preparation methods primarily involve mixing. Therefore, in existing anti-corrosion castable refractory materials and their preparation methods, acid-resistant castables, which are made from water glass and acid-resistant cement, primarily contain silica. While water glass has good fire resistance and corrosion resistance, it is not alkali-resistant. Its curing process involves dehydrating silica; once exposed to a humid environment, the castable becomes brittle and loses its anti-corrosion properties.

[0004] In conclusion, there is an urgent need in the market to develop new types of corrosion-resistant castables and their preparation methods to improve their corrosion resistance and overall performance, while reducing preparation costs and environmental pollution. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a castable material and its preparation method for preventing corrosion of the inner wall of an incinerator by incineration exhaust gas.

[0006] The technical solution of the present invention is: a castable material for preventing the corrosion of the inner wall of an incinerator by incineration exhaust gas, comprising, by weight: 65-75 parts of composite aggregate, 8-10 parts of corrosion-resistant latex, 1-2 parts of binder, 3-5 parts of aluminum powder paste, 1-3 parts of expanded perlite, and 2-3 parts of glass fiber.

[0007] The method for preparing the corrosion-resistant latex is as follows: polyvinyl alcohol, emulsifier, and stabilizer are mixed in a mass ratio of 3-5:1-2:0.5-0.7 to obtain a premix, and then water accounting for 85-95 wt.% of the premix is ​​added and stirred at a speed of 100-200 r / min for 3-8 h to obtain an emulsion.

[0008] Next, a mixture of butyl rubber and acrylic coating at a weight ratio of 1-3:2.3-2.5 is added at a rate of 15-30 g / min, wherein the volume ratio of the mixture to the emulsion is 0.5-0.7:1, and stirring is continued to obtain latex;

[0009] Then, defoaming agent is added to the latex in multiple batches, with an initial addition of 7-9 g / L. Defoaming is carried out at an initial temperature of 90-95°C for 10-15 minutes. Then, the temperature is increased by 5-7% each time, and the amount of defoaming agent added each time is increased by 5-7% compared to the previous addition. The treatment time remains constant each time until the temperature drops to 25-30°C, thus obtaining corrosion-resistant latex.

[0010] The aluminum powder paste contains ≥89% active aluminum.

[0011] Description: This invention addresses the problems of existing acidic castables being susceptible to alkali instability and easily becoming brittle and losing their anti-corrosion properties in humid environments by preparing a corrosion-resistant latex that significantly improves the corrosion resistance of castables. It also possesses excellent bonding properties, enhancing the adhesion between the castable and the substrate, thereby improving the overall strength and stability of the castable. Furthermore, it effectively reduces the amount of binder used, minimizing its environmental pollution. The acrylic coating in the corrosion-resistant latex exhibits strong alkali resistance and breathability, allowing water vapor to pass through while simultaneously blocking water, effectively preventing water from penetrating to the other side of the incinerator lining and affecting its performance and service life. Simultaneously, the water vapor allowed to pass through effectively provides the necessary steam during furnace drying and curing, promoting bonding and reaction between materials, thus improving the overall performance of the castable. The addition of the acrylic coating can replace the need for water-reducing agents, simplifying the preparation process of the anti-corrosion castable, reducing operational steps and process control requirements, and minimizing environmental pollution, resulting in better environmental friendliness.

[0012] In the method for preparing corrosion-resistant latex of the present invention, the pre-mixing of salt-resistant polymers, emulsifiers, and stabilizers promotes their interaction and increases their compatibility. This improved compatibility helps butyl rubber and acrylic coatings mix better in the emulsion, reducing agglomeration and uneven dispersion. Expanded perlite is used to enhance the impermeability of the castable, reducing the penetration of harmful substances in exhaust gas and protecting the inner wall of the incinerator from corrosion. The addition of glass fiber effectively increases the toughness and thermal shock resistance of the castable.

[0013] Furthermore, the method for preparing the composite aggregate is as follows:

[0014] (1) Prepare the raw materials according to the weight ratio of recycled aggregate: natural aggregate: talc powder of 8-12: 3-5: 1-1.5;

[0015] (2) After crushing the recycled aggregate, ball milling is performed for 30-40 minutes to obtain spherical aggregate with a particle size of 10-30 mm. The spherical aggregate is then corroded with a dilute acid solution at a ratio of 10-15 g to 3-5 mL of 8-12 wt.% dilute acid solution until pores are formed on the surface. The corrosion time is 2-5 minutes. Then, glass microspheres are sprayed into the pores on the surface of the corroded spherical aggregate using a shot peening machine until the surface roughness of the spherical aggregate reaches Ra0.1-0.3. The peening is then completed, and the pretreated recycled aggregate is obtained.

[0016] (3) Then take 1 / 2 to 3 / 4 of the talc powder and mix it with the whole amount of pretreated recycled aggregate and heat treat it. The heat treatment temperature is 400 to 450℃ and the heat treatment time is 25 to 35 min to obtain mixture A. Then take the whole amount of natural aggregate and the remaining amount of talc powder, mix them evenly at room temperature, and coarsely grind and sieve them. The sieve particle size is 20 to 50 mm. Then electromagnetically treat it under a magnetic field strength of 500 to 600 Gs for 3 to 5 min. After the treatment, finely grind it and sieve it a second time to obtain mixture B with a particle size of 8 to 10 mm. Then add mixture A to mixture B and adjust the magnetic field strength to 800 to 900 Gs. The electromagnetic treatment time is 5 to 7 min. After the treatment, the composite aggregate is obtained.

[0017] The recycled aggregate is a mixture of any two or more of the following materials in any proportion: slag, crushed stone, waste ceramics, steel slag, and construction solid waste. The glass microspheres have a particle size of 2 to 5 mm.

[0018] Explanation: Glass microspheres possess excellent chemical stability and durability, resisting corrosion and erosion in the environment, thereby improving the durability of spherical aggregate concrete. Furthermore, the corrosion of spherical aggregates with dilute acid solutions can effectively remove impurities and some loose structures from their surfaces, which helps improve the hardness and durability of recycled aggregates. Embedding glass microspheres within the pores can enhance the durability of spherical aggregates while effectively reducing the surface roughness caused by the addition of glass microspheres, thus further reducing the impact of shot peening on the corrosion resistance of castables.

[0019] Furthermore, the shot peening method of the shot peening machine is as follows: the spherical aggregate after corrosion is surface cleaned, and then the treatment agent is added to the glass microspheres at a ratio of 30-50g: 80-100mL, and stirred to obtain a composite; then the composite is attached to the surface of the spherical aggregate using a shot peening machine to complete the shot peening treatment; the treatment agent is obtained by mixing distearate, dimethylammonium lithium montmorillonite and solvent at a volume ratio of 8-12: 15-20; wherein the shot peening angle is 80-90° and the shot peening time is 90-270s.

[0020] Note: Distearate lithium dimethylammonium montmorillonite has good suspension and emulsion stability, which helps maintain the uniform distribution and stability of glass microspheres during spraying, helps reduce the surface roughness of aggregates, and further inhibits salt spray corrosion. Distearate lithium dimethylammonium montmorillonite can also improve the strength and hardness of cast aggregates, and further inhibit salt spray corrosion by increasing the residual stress and hardness of aggregates.

[0021] Furthermore, the solvent is one of water, ethanol, dimethyl sulfoxide, and N-methylpyrrolidone;

[0022] Note: Using solvents such as water, ethanol, dimethyl sulfoxide, or N-methylpyrrolidone to dissolve distearate lithium dimethylammonium montmorillonite has advantages in the preparation of anti-corrosion castables, including strong dissolving ability, high safety, environmental friendliness, high cost-effectiveness, good compatibility with other components, and minimal impact on the stability and performance of distearate lithium dimethylammonium montmorillonite.

[0023] Further, the defoaming agent comprises, by weight parts: 8-12 parts cationic guar gum, 4-6 parts water glass defoaming powder, 2-4 parts epoxy resin, and 1-3 parts glycerin;

[0024] Explanation: Water glass defoaming powder defoams by reducing the surface tension of the foam and disrupting its elastic membrane. Glycerin, a triol with good solubility and plasticizing properties, alters the molecular structure and arrangement of polymers, increasing porosity and thus providing waterproofing and improved temperature resistance. It further coats the surface of the defoamer particles, forming a waterproof film to prevent moisture penetration, thereby enhancing the defoamer's waterproof and water-resistant properties. This effectively extends the defoamer's lifespan, strengthens its stability and reliability, and improves its overall performance. Cationic guar gum acts as a stabilizer, while epoxy resin and glycerin act as a curing agent and plasticizer, respectively, working together to improve the defoaming effect of the polyvinyl alcohol emulsion.

[0025] Furthermore, after the latex is defoamed, the corrosion-resistant latex is subjected to electron irradiation treatment under normal temperature and pressure conditions. The irradiation method is a back-and-forth scanning type, and the irradiation dose is 30-40 kGy.

[0026] Explanation: Electron irradiation treatment increases the cross-linking points between polymer chains in corrosion-resistant latex, forming a tighter network structure. This improves the heat resistance, chemical corrosion resistance, and mechanical strength of the latex, thereby enhancing its resistance to incineration corrosion. Electron irradiation treatment also causes rearrangement and cross-linking of polymer chains in corrosion-resistant latex, improving its aging resistance. This extends the service life of corrosion-resistant latex, allowing it to maintain good protective effects under high temperature and acid / alkali environments.

[0027] Furthermore, the binder is aluminum dihydrogen phosphate or silicate cement;

[0028] Note: Using aluminum dihydrogen phosphate or silicate cement as a binder to prepare anti-corrosion castables has the advantages of good slag resistance, high temperature and corrosion resistance, low price, and high bonding strength. It can effectively resist melting and deformation caused by high temperature incineration.

[0029] The present invention also provides a method for preparing a castable refractory to prevent corrosion of the inner wall of an incinerator by incineration exhaust gas, comprising the following steps:

[0030] S1, Aggregate Premix

[0031] The composite aggregate and expanded perlite are mixed and stirred for 10-15 minutes at a temperature of 3-5℃ and a humidity of 55-65% to obtain a premix. Then, the temperature is raised to 8-12℃ and 10-20% by mass of binder is added and stirred until homogeneous to obtain mixture M.

[0032] S2, Powder Premixing

[0033] The corrosion-resistant latex, aluminum powder paste, and the remaining binder are mixed and stirred for 3-5 minutes at a temperature of 30-35℃ and a humidity of 25-35%RH to obtain mixture N.

[0034] S3, Casting

[0035] Add water accounting for 2-4% of the mass fraction of the mixture M to the mixture M and stir for 8-10 minutes. Then add the mixture N and continue stirring for 15-20 minutes to obtain the mixed aggregate. Finally, add water accounting for 8-10% of the mass fraction of the mixed aggregate and the total amount of glass fiber, and continue stirring for 23-27 minutes to obtain the wet mixture. After molding the wet mixture, the precast refractory is obtained.

[0036] S4, Post-processing

[0037] The precast refractory obtained in step S3 is cured for 7 to 15 days and then dried at 70 to 80°C for 30 to 60 minutes to obtain the castable refractory.

[0038] Explanation: The castable obtained using the above preparation method, by mixing composite aggregate with expanded perlite, can compensate for the insufficient mechanical strength of expanded perlite, thus obtaining a composite material with both good thermal insulation performance and a certain strength. Mixing is performed first at low temperatures, followed by heating and adding the binder. This step promotes homogenization and prevents the material from expanding or cracking too quickly during heating, thus maintaining the material's integrity and stability. Within the temperature range of this scheme, the activity of particles and powders in the castable is ensured, increasing intermolecular thermal motion and effectively controlling bubble formation, resulting in a denser castable. Controlling the humidity of the aggregates and powders allows the binder to effectively combine with each material, forming a homogeneous mixture. Excessive humidity may cause agglomeration or clumping, reducing the uniformity of distribution in the mixture; excessively low humidity may cause the material to become too dry, making it difficult to mix thoroughly with other components.

[0039] Further, in step S3, the molding process is a combined process of vibration molding and pressure molding; the molding process is as follows: the casting material is compacted in layers using a vibratory rod, with each layer being 250-300 mm thick, the vibration spacing being 240-260 mm, and the vibration frequency being 50-80 Hz. After the processing is completed, the molded casting material is placed in a press and simultaneously subjected to microwave irradiation treatment; wherein the pressure of the press is 0.2-0.3 MPa, the processing time is 10-15 min, and the power of the microwave irradiation is 10-15 kW.

[0040] Note: Compared to using either pressure molding or vibration molding alone, combining vibration molding and pressure molding in the molding process of wet mixtures allows for better compaction and uniform distribution, which helps improve product density and strength, thereby enhancing product performance. Microwave irradiation during pressure molding can further reduce the penetration of corrosive media and improve the material's corrosion resistance.

[0041] The beneficial effects of this invention are:

[0042] (1) This invention solves the problems of acidic castables being intolerant to alkalis and easily becoming brittle and losing their anti-corrosion properties in humid environments by preparing a corrosion-resistant latex that significantly improves the corrosion resistance of castables and also has a waterproof effect. At the same time, the addition of this corrosion-resistant latex can effectively improve the overall strength and stability of the castable, thereby improving the performance of the castable. Furthermore, the preparation method of pre-mixing salt-resistant polymers, emulsifiers and stabilizers, and then adding butyl rubber and acrylic coatings and mixing them together effectively promotes the interaction between them, increases their compatibility, and thus effectively reduces the phenomenon of agglomeration and uneven dispersion.

[0043] (2) This invention utilizes the corrosive effect of dilute acid solution on spherical aggregates to remove impurities and some loose structures from the surface of the spherical aggregates, thereby improving the hardness and durability of the spherical aggregates. Then, glass microspheres with good chemical stability and durability, which can resist corrosion and erosion in the environment, are attached to the spherical aggregates with porous surfaces through shot blasting. This effectively reduces the roughness of the spherical aggregate surface caused by the addition of glass microspheres. The above method can improve the performance of spherical aggregates while effectively reducing the impact of shot blasting on the corrosion resistance of castables.

[0044] (3) The present invention mixes the composite aggregate and expanded perlite at low temperature first, and then adds the binder after a slight increase in temperature. This step can ensure that the binder mixes better with the composite aggregate and expanded perlite, and can also prevent the materials from expanding or cracking too quickly during the heating process, which is beneficial to maintaining the integrity and stability of the materials. By adjusting the temperature range of the powder premixing, the particles and powder in the castable are kept in a relatively active state, increasing the thermal motion between molecules and effectively controlling the formation of bubbles, thereby obtaining a denser castable. By controlling the humidity of the aggregate and powder, the binder can effectively combine with each material to form a uniform mixture. Attached Figure Description

[0045] Figure 1 This is a graph showing the trend of corrosion resistance of the castables prepared in Examples 1 to 13 and Comparative Examples 1 to 3 of the present invention.

[0046] Figure 2 This is a graph showing the trend of heat resistance of the castables prepared in Examples 1 to 13 and Comparative Examples 1 to 3 of the present invention.

[0047] Figure 3 This is a graph showing the trend of corrosion resistance of the castables prepared in Examples 1, 14 to 23 and Comparative Examples 4 to 6 of the present invention.

[0048] Figure 4 This is a graph showing the trend of heat resistance of the castables prepared in Examples 1, 14 to 23 and Comparative Examples 4 to 6 of the present invention.

[0049] Figure 5 This is a graph showing the trend of corrosion resistance of the castables prepared in Examples 1, 24 to 33 and Comparative Examples 7 to 9 of the present invention.

[0050] Figure 6 This is a graph showing the trend of heat resistance of the castables prepared in Examples 1, 24 to 33 and Comparative Examples 7 to 9 of the present invention. Detailed Implementation

[0051] To further illustrate the methods and effects of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with experiments.

[0052] Example 1: A castable for preventing corrosion of the inner wall of an incinerator by incineration exhaust gas, comprising by weight: 70 parts composite aggregate, 9 parts corrosion-resistant latex, 1.5 parts binder, 4 parts aluminum powder paste, 5 parts expanded perlite, and 2.5 parts glass fiber.

[0053] The binder is aluminum dihydrogen phosphate;

[0054] The preparation method of corrosion-resistant latex is as follows: polyvinyl alcohol, emulsifier, and stabilizer are mixed in a mass ratio of 4:1.5:0.6 to obtain a premix. Then, water accounting for 90 wt.% of the premix is ​​added and stirred at 150 r / min for 5 h to obtain an emulsion. Any commercially available emulsifier can be used. In this embodiment, polyglycerol ester is used as the emulsifier.

[0055] Next, a mixture of butyl rubber and acrylic coating at a weight ratio of 2:2.4 was added at a rate of 22 g / min, and stirring was continued to obtain latex; wherein, the volume ratio of mixture to emulsion was 0.6:1.

[0056] Then, defoaming agent was added to the latex in multiple batches. The initial addition amount of defoaming agent was 8 g / L, and defoaming treatment was carried out at an initial temperature of 93℃ for 13 min. Then, the temperature was 65% of the previous temperature each time, and the amount of defoaming agent added each time was increased by 6% compared to the previous addition amount. The treatment time remained unchanged each time until the temperature dropped to 28℃, and corrosion-resistant latex was obtained.

[0057] The defoaming agent, by weight, includes: 10 parts cationic guar gum, 5 parts water glass defoaming powder, 3 parts epoxy resin, and 2 parts glycerin;

[0058] After latex defoaming treatment, the corrosion-resistant latex was subjected to electron irradiation treatment under normal temperature and pressure conditions. The irradiation method was a back-and-forth scanning method, and the irradiation dose was 35 kGy.

[0059] The aluminum powder paste contains 89% active aluminum.

[0060] The preparation method of composite aggregate is as follows:

[0061] (1) Prepare the raw materials according to the weight ratio of recycled aggregate: natural aggregate: talc powder of 10:4:1.25;

[0062] (2) After crushing the recycled aggregate, ball milling was performed for 35 minutes to obtain spherical aggregate with a particle size of 20 mm. The spherical aggregate was corroded with dilute acid solution at a ratio of 13 g: 4 mL of spherical aggregate: 10 wt.% dilute acid solution until pores were formed on the surface. The corrosion time was 3 minutes. Then, glass microspheres were sprayed into the pores on the surface of the corroded spherical aggregate using a shot peening machine until the surface roughness of the recycled aggregate reached Ra0.2. The peening was completed, and the pretreated recycled aggregate was obtained.

[0063] (3) Then take 5 / 8 of the talc powder and the whole amount of pretreated recycled aggregate for heat treatment. The heat treatment temperature is 425℃ and the heat treatment time is 30min to obtain mixture A. Then take the whole amount of natural aggregate and the remaining amount of talc powder, mix them evenly at room temperature, and then coarsely grind and sieve them. The sieve particle size is 20-50mm. Then electromagnetically treat them under a magnetic field strength of 550Gs for 4min. After the treatment, finely grind them and sieve them a second time to obtain mixture B with a particle size of 8-10mm. Then add mixture A to mixture B and adjust the magnetic field strength to 850Gs. The electromagnetic treatment time is 6min. After the treatment, the composite aggregate is obtained.

[0064] Among them, the recycled aggregate is a mixture of slag and crushed stone in a weight ratio of 1:1, and the glass microspheres have a particle size of 2-5 mm.

[0065] The shot peening method is as follows: The spherical aggregate after corrosion is surface-cleaned. Then, the treatment agent is added to the glass microspheres at a ratio of 40g:90mL, and the mixture is stirred to obtain a composite. The composite is then adhered to the surface of the spherical aggregate using a shot peening machine to complete the shot peening treatment. The treatment agent is obtained by mixing distearate, dimethylammonium lithium montmorillonite, and solvent at a volume ratio of 10:17. The shot peening angle is 85°, and the shot peening time is 180s. The solvent is water.

[0066] This embodiment also provides a method for preparing a castable refractory to prevent corrosion of the inner wall of an incinerator by incineration exhaust gas, comprising the following steps:

[0067] S1, Aggregate Premix

[0068] The composite aggregate and expanded perlite were mixed and stirred for 13 minutes at a temperature of 4℃ and a humidity of 60% to obtain a premix. Then, the temperature was raised to 10℃ and 15% by mass of binder was added. The mixture was stirred and mixed to obtain mixture M.

[0069] S2, Powder Premixing

[0070] The corrosion-resistant latex, aluminum powder paste, and the remaining binder were mixed and stirred for 4 minutes at a temperature of 33°C and a humidity of 30%RH to obtain mixture N.

[0071] S3, Casting

[0072] Add water accounting for 3% of the mass fraction of mixture M to mixture M and stir for 9 minutes. Then add mixture N and continue stirring for 18 minutes to obtain mixed aggregate. Finally, add water accounting for 9% of the mass of mixed aggregate and all the glass fiber, and continue stirring for 25 minutes to obtain wet mixture. After casting and molding the wet mixture, obtain precast material.

[0073] S4, Post-processing

[0074] The precast refractory obtained in step S3 is cured for 10 days and then dried at 75°C for 45 minutes to obtain the castable refractory.

[0075] In step S3, the molding process is a combined process of vibration molding and pressure molding. The molding process is as follows: the casting material is compacted in layers using a vibratory rod, with each layer being 275 mm thick, the vibration spacing being 250 mm, and the vibration frequency being 50–80 Hz. After the process is completed, the molded casting material is placed in a press and simultaneously subjected to microwave irradiation treatment. The press pressure is 0.25 MPa, the treatment time is 13 min, and the microwave irradiation power is 13 kW.

[0076] Example 2: Unlike Example 1, a castable material for preventing incineration exhaust gas from corroding the inner wall of an incinerator includes, by weight: 65 parts composite aggregate, 8 parts corrosion-resistant latex, 1 part binder, 3 parts aluminum powder paste, 1 part expanded perlite, and 2 parts glass fiber.

[0077] Example 3: Unlike Example 1, a castable material for preventing incineration exhaust gas from corroding the inner wall of an incinerator includes, by weight: 75 parts composite aggregate, 10 parts corrosion-resistant latex, 2 parts binder, 5 parts aluminum powder paste, 3 parts expanded perlite, and 3 parts glass fiber.

[0078] Example 4: Unlike Example 1, in the preparation method of corrosion-resistant latex, polyvinyl alcohol, emulsifier and stabilizer are mixed in a mass ratio of 3:1:0.5 to obtain a premix. Then, water accounting for 85 wt.% of the premix is ​​added and stirred at 100 r / min for 8 h to obtain an emulsion.

[0079] Example 5: Unlike Example 1, in the preparation method of corrosion-resistant latex, polyvinyl alcohol, emulsifier and stabilizer are mixed in a mass ratio of 5:2:0.7 to obtain a premix. Then, water accounting for 95 wt.% of the premix is ​​added and stirred at 200 r / min for 3 h to obtain an emulsion.

[0080] Example 6: Unlike Example 1, a mixture of butyl rubber and acrylic coating at a weight ratio of 1:2.3 was added at a rate of 15 g / min, and stirring was continued to obtain latex; wherein the volume ratio of mixture to emulsion was 0.5:1.

[0081] Example 7: Unlike Example 1, a mixture of butyl rubber and acrylic coating at a weight ratio of 3:2.5 was added at a rate of 30 g / min, and stirring was continued to obtain latex; wherein the volume ratio of mixture to emulsion was 0.7:1.

[0082] Example 8: Unlike Example 1, defoamer was added to the latex in multiple batches. The initial amount of defoamer was 7 g / L, and defoaming was performed at an initial temperature of 90°C for 15 min. Then, the temperature was 60% of the previous temperature each time, and the amount of defoamer added each time was increased by 5% compared to the previous amount. The treatment time remained constant each time until the temperature dropped to 25°C, resulting in corrosion-resistant latex.

[0083] Example 9: Unlike Example 1, defoamer was added to the latex in multiple batches. The initial addition amount of defoamer was 9 g / L, and defoaming treatment was carried out at an initial temperature of 95°C for 10 min. Then, the temperature was 70% of the previous temperature each time, and the amount of defoamer added each time increased by 7% compared to the previous addition amount. The treatment time remained constant each time until the temperature dropped to 30°C, resulting in corrosion-resistant latex.

[0084] Example 10: Unlike Example 1, the defoamer, by mass parts, includes: 8 parts cationic guar gum, 4 parts water glass defoaming powder, 2 parts epoxy resin, and 1 part glycerin.

[0085] Example 11: Unlike Example 1, the defoamer, by mass parts, includes: 12 parts cationic guar gum, 6 parts water glass defoaming powder, 4 parts epoxy resin, and 3 parts glycerin.

[0086] Example 12: Unlike Example 1, after the latex was defoamed, the corrosion-resistant latex was subjected to electron irradiation treatment at room temperature and pressure. The irradiation method was a back-and-forth scanning method, and the irradiation dose was 30 kGy.

[0087] Example 13: Unlike Example 1, after the latex was defoamed, the corrosion-resistant latex was subjected to electron irradiation treatment at room temperature and pressure. The irradiation method was a back-and-forth scanning method, and the irradiation dose was 40 kGy.

[0088] Example 14: Unlike Example 1, in the preparation method (1) of composite aggregate, each raw material is prepared according to the weight ratio of recycled aggregate: natural aggregate: talc powder of 8:3:1.

[0089] Example 15: Unlike Example 1, in the preparation method (1) of composite aggregate, each raw material is prepared according to the weight ratio of recycled aggregate: natural aggregate: talc powder of 12:5:1.5.

[0090] Example 16: Unlike Example 1, in the preparation method (2) of composite aggregate, the recycled aggregate is crushed and ball-milled for 30 minutes to obtain spherical aggregate with a particle size of 10 mm. The spherical aggregate is corroded with dilute acid solution at a ratio of 10 g: 3 mL according to the ratio of spherical aggregate: 8 wt.% dilute acid solution. The surface of the spherical aggregate is corroded until pores are generated on the surface. The corrosion time is 5 minutes. Then, glass microspheres are sprayed into the pores on the surface of the corroded spherical aggregate using a shot peening machine until the surface roughness of the spherical aggregate reaches Ra0.3. The peening is completed, and the pretreated recycled aggregate is obtained.

[0091] Example 17: Unlike Example 1, in the preparation method (2) of composite aggregate, the recycled aggregate is crushed and ball-milled for 40 minutes to obtain spherical aggregate with a particle size of 10-30 mm. The spherical aggregate is corroded with dilute acid solution at a ratio of 15 g: 5 mL of spherical aggregate: 12 wt.% dilute acid solution until pores are formed on the surface. The corrosion time is 2 minutes. Then, glass microspheres are sprayed into the pores on the surface of the corroded spherical aggregate using a shot peening machine until the surface roughness of the spherical aggregate reaches Ra0.1, and the peening is completed to obtain the pretreated recycled aggregate.

[0092] Example 18: Unlike Example 1, in the preparation method (3) of composite aggregate, half of the talc powder is mixed with the whole amount of pretreated recycled aggregate and then heat-treated at a temperature of 400℃ for 35 minutes to obtain mixture A; then the whole amount of natural aggregate and the remaining amount of talc powder are mixed evenly at room temperature and coarsely ground and sieved with a particle size of 20-50 mm. Then, electromagnetic treatment is performed under a magnetic field strength of 500 Gs for 5 minutes. After the treatment, fine grinding is performed and secondary sieving is performed to obtain mixture B with a particle size of 8-10 mm. Then, mixture A is added to mixture B and the magnetic field strength is adjusted to 800 Gs. The electromagnetic treatment time is 7 minutes. After the treatment, composite aggregate is obtained.

[0093] Example 19: Unlike Example 1, in the preparation method (3) of composite aggregate, 3 / 4 of the talc powder is mixed with the whole amount of pretreated recycled aggregate and then heat-treated at a temperature of 450°C for 25 minutes to obtain mixture A; then the whole amount of natural aggregate and the remaining amount of talc powder are mixed evenly at room temperature and coarsely ground and sieved with a particle size of 20-50 mm. Then, electromagnetic treatment is performed for 3 minutes under a magnetic field strength of 600 Gs. After the treatment, fine grinding is performed and secondary sieving is performed to obtain mixture B with a particle size of 8-10 mm. Then, mixture A is added to mixture B and the magnetic field strength is adjusted to 900 Gs. The electromagnetic treatment time is 5 minutes. After the treatment, composite aggregate is obtained.

[0094] Example 20: Unlike Example 1, the shot peening method of the shot peening machine is as follows: the surface of the spherical aggregate after corrosion is cleaned, and then the treatment agent is added to the glass microspheres according to the ratio of glass microspheres to treatment agent of 30g:80mL, and the mixture is stirred to obtain a composite; then the composite is attached to the surface of the spherical aggregate by the shot peening machine to complete the shot peening treatment; wherein, the shot peening angle is 80° and the shot peening time is 270s.

[0095] Example 21: Unlike Example 1, the shot peening method of the shot peening machine is as follows: the surface of the spherical aggregate after corrosion is cleaned, and then the treatment agent is added to the glass microspheres according to the ratio of glass microspheres to treatment agent of 50g:100mL, and the mixture is stirred to obtain a composite; then the composite is attached to the surface of the spherical aggregate by the shot peening machine to complete the shot peening treatment; wherein, the shot peening angle is 90° and the shot peening time is 90s.

[0096] Example 22: Unlike Example 1, the treatment agent was obtained by mixing distearate dimethylammonium lithium montmorillonite and a solvent at a volume ratio of 8:15; the solvent was water.

[0097] Example 23: Unlike Example 1, the treatment agent was obtained by mixing distearate dimethylammonium lithium montmorillonite and solvent at a volume ratio of 12:20; the solvent was N-methylpyrrolidone.

[0098] Example 24: Unlike Example 1, in step S1, the composite aggregate and expanded perlite are mixed and stirred for 15 minutes at a temperature of 3°C and a humidity of 55% to obtain a premix. Then, the temperature is raised to 8°C and 10% by mass of binder is added and stirred to obtain mixture M.

[0099] Example 25: Unlike Example 1, in step S1, the composite aggregate and expanded perlite are mixed and stirred for 10 minutes at a temperature of 5°C and a humidity of 65% to obtain a premix. Then, the temperature is raised to 12°C and 20% by mass of binder is added and stirred to obtain mixture M.

[0100] Example 26: Unlike Example 1, in step S2, the corrosion-resistant latex, aluminum powder paste and the remaining amount of binder are mixed and stirred for 5 minutes at a temperature of 30°C and a humidity of 25% to obtain mixture N.

[0101] Example 27: Unlike Example 1, in step S2, the corrosion-resistant latex, aluminum powder paste and the remaining amount of binder are mixed and stirred for 3 minutes at a temperature of 35°C and a humidity of 35% to obtain mixture N.

[0102] Example 28: Unlike Example 1, in step S3, water accounting for 2% of the mass fraction of mixture M is added to mixture M and stirred for 10 minutes. Then, mixture N is added and stirred for another 15 minutes to obtain mixed aggregate. Finally, water accounting for 8% of the mass of mixed aggregate and all the glass fiber are added and stirred for another 27 minutes to obtain wet mixture. After casting and molding the wet mixture, precast material is obtained.

[0103] Example 29: Unlike Example 1, in step S3, water accounting for 4% of the mass of mixture M is added to mixture M and stirred for 8 minutes. Then, mixture N is added and stirred for another 20 minutes to obtain mixed aggregate. Finally, water accounting for 10% of the mass of mixed aggregate and all the glass fiber are added and stirred for another 23 minutes to obtain wet mixture. After casting and molding the wet mixture, precast material is obtained.

[0104] Example 30: Unlike Example 1, in step S3, the molding process is a combined process of vibration molding and pressure molding; the molding process is as follows: the casting material is compacted in layers using a vibratory bar, with each layer being 250mm thick, the vibration spacing being 240mm, and the vibration frequency being 50Hz. After the processing is completed, the molded casting material is placed in a press and simultaneously subjected to microwave irradiation treatment; wherein, the pressure of the press is 0.2MPa, the processing time is 15min, and the power of the microwave irradiation is 10kW.

[0105] Example 31: Unlike Example 1, in step S3, the molding process is a combined process of vibration molding and pressure molding; the molding process is as follows: the casting material is compacted in layers using a vibratory bar, with each layer being 300mm thick, the vibration spacing being 260mm, and the vibration frequency being 80Hz. After the processing is completed, the molded casting material is placed in a press and simultaneously subjected to microwave irradiation treatment; wherein, the pressure of the press is 0.3MPa, the processing time is 10min, and the power of the microwave irradiation is 15kW.

[0106] Example 32: Unlike Example 1, in step S4, the precast refractory obtained in step S3 is cured for 7 days and then dried at 70°C for 60 minutes to obtain the castable refractory.

[0107] Example 33: Unlike Example 1, in step S4, the precast refractory obtained in step S3 is cured for 15 days and then dried at 80°C for 30 minutes to obtain the castable refractory.

[0108] Experimental Example: The corrosion resistance and heat resistance of the castables obtained in Examples 1-33 and Comparative Examples 1-9 to incineration exhaust gas were tested. Corrosion resistance tests included acid resistance, alkali resistance, and salt spray resistance. The acid resistance test method was to immerse the castable in a 40% sulfuric acid solution at room temperature for 3 days and then test the degree of corrosion. The alkali resistance test method was to immerse the castable in a 40% sodium hydroxide solution at room temperature for 3 days and then test the degree of corrosion. The salt spray resistance test method was to immerse the castable in a 5% sodium chloride solution at room temperature for 3 days and then test the degree of corrosion. The average corrosion rate of the acid resistance, alkali resistance, and salt spray resistance test results was taken as the corrosion resistance test result. The thermal conductivity was determined according to YB / T059. The investigation is as follows:

[0109] 1. Investigate the effects of the component ratio of castables and the preparation method of corrosion-resistant latex on the performance of castables.

[0110] Comparative Example 1: Unlike Example 1, the acrylic coating was replaced with a water-reducing agent in the preparation of the corrosion-resistant latex.

[0111] Comparative Example 2: Unlike Example 1, the defoaming agent was added to the latex in one step for defoaming treatment.

[0112] Comparative Example 3: Unlike Example 1, the step of electron irradiation treatment of the corrosion-resistant latex was missing.

[0113] Conclusion: From Figure 1 , Figure 2The trend chart of castable performance changes shows that the performance differences of the castables prepared according to this method are relatively small. However, a comparison of the trends of Examples 1-7 and Comparative Example 1 shows that replacing the acrylic coating with a water-reducing agent significantly increases the corrosion rate of the castable, while slightly increasing the thermal conductivity. This indicates that although the water-reducing agent has the characteristic of adsorbing onto the surface of cement particles and changing the charge distribution between cement particles, thereby reducing the flocculation state between cement particles, releasing more free water, and improving the fluidity of concrete, the lack of alkali resistance by the water-reducing agent itself leads to a decrease in the corrosion resistance of the castable. Furthermore, a comparison of the trends of Examples 1, 8-9, and Comparative Example 2 shows that adding the defoamer all at once versus adding it in multiple stages also affects the corrosion resistance of the castable. The performance of the castables varies. Specifically, by gradually lowering the temperature and adding defoaming powder in stages, the dispersion rate of the defoamer and the kinetics of the defoaming reaction can be controlled. This helps maintain the performance stability of the latex at high temperatures, thereby improving the performance of the castable. However, adding a large amount of defoaming powder at once may increase the risk of thermal decomposition of the latex at high temperatures, thus affecting the performance of the castable. According to the trend comparison of Examples 1, 10-13 and Comparative Example 3, the performance of the corrosion-resistant latex without electron irradiation treatment also decreased. This is mainly because electron irradiation treatment can increase the cross-linking points between the polymer chains in the corrosion-resistant latex, making it form a tighter network structure. This can improve the heat resistance, chemical corrosion resistance and mechanical strength of the corrosion-resistant latex, thereby enhancing its resistance to incineration corrosion.

[0114] 2. Investigate the influence of composite aggregate preparation methods on castable properties.

[0115] Comparative Example 4: Unlike Example 1, the glass microspheres were directly mixed and stirred with the recycled aggregate.

[0116] Comparative Example 5: Unlike Example 1, no electromagnetic treatment was performed during the mixing process of mixture B and mixture A.

[0117] Comparative Example 6: Unlike Example 1, the distearate dimethylammonium lithium montmorillonite in the treatment agent was replaced with acetyl glucosamine.

[0118] Conclusion: From Figure 3 , Figure 4The performance trends of the castables prepared in Examples 1, 14-23, and Comparative Examples 4-6 show that the corrosion resistance and heat resistance of the castable prepared in Comparative Example 4 exhibit a significant downward trend. This is because when glass microspheres are directly mixed with recycled aggregate, the surface of the glass microspheres is usually smooth, resulting in a small contact area with the recycled aggregate, which may lead to insufficient bonding between the two. Therefore, the castable prepared by direct mixing may have many pores at the microscopic level. These pores may become channels for corrosive media to penetrate, thus affecting its corrosion resistance. When glass microspheres are embedded in the recycled aggregate after etching micropores on the surface, the presence of micropores facilitates better embedding of the glass microspheres on the surface of the recycled aggregate and does not obscure the performance of the glass microspheres, thereby enhancing the heat resistance and corrosion resistance of the recycled aggregate. As shown in the figures, the performance of the castable prepared in Comparative Example 5 slightly decreased due to the reduced mixing effect of the composite aggregate. Electromagnetic treatment of the natural aggregate can activate the surface of the aggregate, increase its surface energy, and improve its bonding ability with other materials. Further fine grinding followed by the addition of recycled aggregate and increasing the intensity of electromagnetic treatment can further improve the density of the aggregate, reduce porosity, and thus improve its corrosion resistance. In Comparative Example 6, the replacement of distearate dimethylammonium montmorillonite with acetylglucosamine resulted in a significant decrease in the heat resistance of the castable. The above substitution had a relatively small impact on corrosion resistance because distearate dimethylammonium montmorillonite, as a stable emulsifier and suspending agent, may more effectively fix the glass microspheres on the surface of the recycled aggregate, preventing them from falling off. At the same time, because distearate dimethylammonium montmorillonite can stabilize the thermal stability viscosity of the oil phase in the emulsion, it is more suitable for use in high-temperature environments, while acetylglucosamine is not stable enough at high temperatures, resulting in poor heat resistance of the castable in Comparative Example 6.

[0119] 3. Investigate the influence of the preparation steps of castables on their properties.

[0120] Comparative Example 7: Unlike Example 1, the humidity during the powder premixing process is not limited.

[0121] Comparative Example 8: Unlike Example 1, the molding process was vibration molding.

[0122] Comparative Example 9: Unlike Example 1, no microwave irradiation treatment was performed during the molding process.

[0123] Conclusion: From Figure 5 , Figure 6The performance trends of the castables prepared in Examples 1, 24-33, and Comparative Examples 7-9 show that the corrosion resistance and heat resistance of the castable prepared in Comparative Example 7 also showed a significant downward trend. The requirements for environmental humidity in powder mixing are more stringent because powder materials are usually sensitive to moisture and are prone to absorbing moisture and clumping, thus affecting the mixing quality and the performance of the final product. The trend changes in Examples 1, 30-31, and Comparative Examples 8 and 9 show that using a combination of vibration molding and pressure molding for the casting treatment, compared with using pressure molding or vibration molding alone, can achieve better compaction and uniform distribution of the wet mixture during the molding process. This helps to improve the density and strength of the product, thereby improving the product performance. However, the lack of microwave irradiation treatment in Comparative Example 9 weakens the molding effect during the casting process, further increasing the penetration of corrosive media and reducing the corrosion resistance of the material. Therefore, considering all factors, Example 1 is selected as the optimal solution.

Claims

1. A castable refractory for preventing corrosion of the inner wall of an incinerator by combustion exhaust gas, characterized in that, By weight, it includes: 65-75 parts of composite aggregate, 8-10 parts of corrosion-resistant latex, 1-2 parts of binder, 3-5 parts of aluminum powder paste, 1-3 parts of expanded perlite, and 2-3 parts of glass fiber; The method for preparing the corrosion-resistant latex is as follows: polyvinyl alcohol, emulsifier, and stabilizer are mixed in a mass ratio of 3~5:1~2:0.5~0.7 to obtain a premix, and then water accounting for 85~95wt.% of the premix is ​​added and stirred at a speed of 100~200r / min for 3~8h to obtain an emulsion. Next, a mixture of butyl rubber and acrylic coating at a weight ratio of 1-3:2.3-2.5 is added at a rate of 15-30 g / min, wherein the volume ratio of the mixture to the emulsion is 0.5-0.7:1, and stirring is continued to obtain latex; Then, defoaming agent is added to the latex in multiple batches, with an initial addition of 7-9 g / L. Defoaming is carried out at an initial temperature of 90-95°C for 10-15 minutes. Then, the temperature is increased by 5-7% each time, and the amount of defoaming agent added each time is increased by 5-7% compared to the previous addition. The treatment time remains constant each time until the temperature drops to 25-30°C, thus obtaining corrosion-resistant latex. The aluminum powder paste contains ≥89% active aluminum. The method for preparing the composite aggregate is as follows: (1) Prepare each raw material according to the weight ratio of recycled aggregate: natural aggregate: talc powder of 8~12:3~5:1~1.5; (2) After crushing the recycled aggregate, ball milling is performed for 30-40 minutes to obtain spherical aggregate with a particle size of 10-30 mm. The spherical aggregate is corroded with dilute acid solution at a ratio of 10-15 g: 3-5 mL to 8-12 wt.% of mass concentration until pores are formed on the surface. The corrosion time is 2-5 minutes. Then, glass microspheres are sprayed into the pores on the surface of the corroded spherical aggregate using a shot blasting machine until the surface roughness of the spherical aggregate reaches Ra0.1-0.

3. The blasting is completed, and the pretreated recycled aggregate is obtained. (3) Then take 1 / 2 to 3 / 4 of the talc powder and mix it with the whole amount of pretreated recycled aggregate and heat treat it. The heat treatment temperature is 400 to 450℃ and the heat treatment time is 25 to 35 min to obtain mixture A. Then take the whole amount of natural aggregate and the remaining amount of talc powder and mix them evenly at room temperature and coarsely grind and sieve them. The sieve particle size is 20 to 50 mm. Then electromagnetically treat it for 3 to 5 min under a magnetic field strength of 500 to 600 Gs. After the treatment, finely grind it and sieve it twice to obtain mixture B with a particle size of 8 to 10 mm. Then add mixture A to mixture B and adjust the magnetic field strength to 800 to 900 Gs. The electromagnetic treatment time is 5 to 7 min. After the treatment, the composite aggregate is obtained. Among them, the recycled aggregate is any two or more of the following materials mixed in any proportion: slag, crushed stone, waste ceramics, steel slag, and construction solid waste; and the particle size of the glass microspheres is 2-5 mm. After the latex was defoamed, the corrosion-resistant latex was subjected to electron irradiation treatment at room temperature and pressure. The irradiation method was a back-and-forth scanning method, and the irradiation dose was 30~40kGy. The method for preparing the castable includes the following steps: S1, Aggregate Premix The composite aggregate and expanded perlite are mixed and stirred for 10-15 minutes at a temperature of 3-5℃ and a humidity of 55-65% to obtain a premix. Then, the temperature is raised to 8-12℃ and 10-20% by mass of binder is added and stirred until homogeneous to obtain mixture M. S2, Powder Premixing The corrosion-resistant latex, aluminum powder paste, and the remaining binder are mixed and stirred for 3-5 minutes at a temperature of 30-35℃ and a humidity of 25-35%RH to obtain mixture N. S3, Casting Add water accounting for 2-4% of the mass fraction of the mixture M to the mixture M and stir for 8-10 minutes. Then add the mixture N and continue stirring for 15-20 minutes to obtain the mixed aggregate. Finally, add water accounting for 8-10% of the mass of the mixed aggregate and all the glass fiber, and continue stirring for 23-27 minutes to obtain the wet mixture. After molding the wet mixture, the precast refractory is obtained. The molding process is a combined process of vibration molding and pressure molding; the molding process is as follows: the casting material is compacted in layers using a vibratory bar, with each layer being 250-300mm thick, the vibration spacing being 240-260mm, and the vibration frequency being 50-80Hz. After the process is completed, the molded casting material is placed in a press and simultaneously subjected to microwave irradiation treatment; wherein the press pressure is 0.2-0.3MPa, the treatment time is 10-15min, and the microwave irradiation power is 10-15kW. S4, Post-processing The precast refractory obtained in step S3 is cured for 7-15 days and then dried at 70-80℃ for 30-60 minutes to obtain the castable refractory. The shot peening method of the shot peening machine is as follows: the spherical aggregate after corrosion is surface cleaned, and then the treatment agent is added to the glass microspheres at a ratio of 30~50g:80~100mL, and stirred to obtain a composite; then the composite is attached to the surface of the spherical aggregate using a shot peening machine to complete the shot peening treatment; the treatment agent is obtained by mixing distearate, dimethylammonium lithium montmorillonite and solvent at a volume ratio of 8~12:15~20; wherein, the shot peening angle is 80~90°, and the shot peening time is 90~270s.

2. The castable refractory for preventing corrosion of the incinerator inner wall by incineration exhaust gas as described in claim 1, characterized in that, The solvent is one of water, ethanol, dimethyl sulfoxide, and N-methylpyrrolidone.

3. The castable refractory for preventing corrosion of the incinerator inner wall by incineration exhaust gas as described in claim 1, characterized in that, The defoaming agent, by weight, comprises: 8-12 parts cationic guar gum, 4-6 parts water glass defoaming powder, 2-4 parts epoxy resin, and 1-3 parts glycerin.

4. The castable refractory for preventing corrosion of the incinerator inner wall by incineration exhaust gas as described in claim 1, characterized in that, The binder is aluminum dihydrogen phosphate or silicate cement.

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