Insulation board for exterior wall made of fly ash from garbage power plant and preparation method thereof

Abstract

The present invention discloses an insulation board for exterior walls made from fly ash from a garbage power plant and a preparation method thereof. The invention belongs to the technical field of thermal insulation material preparation and comprises the following raw materials: modified nanocellulose, thermal insulation filler, dispersant, foaming agent, polyvinyl alcohol, modified fly ash, AlCl3·6H2O, ethanol, 1,2-propylene oxide, acrylamide solution, initiator, crosslinking agent, and deionized water. The fly ash is modified by ultrasonic hydrothermal treatment to change its crystal phase and achieve the effects of decomposing dioxins and immobilizing heavy metals. Diatomaceous earth, aluminate cement, modified fly ash, and kaolin are used in the thermal insulation filler, resulting in excellent thermal insulation properties. Polyvinyl alcohol solution is used as a stabilizer and adhesive in the foam slurry. The board is suitable for a variety of building exterior walls. Furthermore, since the freeze-dried gel layer has viscoelasticity, it can prevent cracking, bulging, and displacement caused by deformation of the board, making it durable.

Description

Technical Field

[0001] The invention relates to the technical field of thermal insulation materials, in particular to a thermal insulation board for exterior walls made of fly ash from a garbage power plant and a preparation method thereof. Background Art

[0002] Power plant fly ash is a type of solid gasification byproduct generated in a gasifier by reacting unreacted coal particles or coal particles with a gasifying agent. These solid particles are then carried out by syngas, condensed, and agglomerated, resulting in the capture of fine particles. Due to partial gasification and water vapor activation, fly ash is incompletely oxidized, with numerous transitional, mesopores, and macropores on its surface. Its particle size ranges primarily from 1 to 100 μm. Chemically, power plant fly ash contains SiO₂, Al₂O₃, Fe₂O₃, and CaO, along with small amounts of metallic elements such as K, Na, and Mg, and minerals such as quartz, mullite, and iron oxide, demonstrating its usable properties. However, power plant fly ash also contains small amounts of heavy metals such as Pb, Cr, and Cd, as well as toxic organic compounds such as dioxins and polychlorinated biphenyls. Ambient temperature treatment methods suffer from poor stabilization of heavy metals in fly ash, are prone to secondary leaching, and fail to degrade dioxins. High-temperature treatment also carries the disadvantage of high processing costs. Summary of the Invention

[0003] The purpose of the present invention is to provide an insulation board for exterior walls made of fly ash from a garbage power plant and a preparation method thereof, so as to solve the problems raised in the background technology. By subjecting the fly ash to ultrasonic hydrothermal treatment modification, its crystal phase is changed and the effect of decomposing dioxins and immobilizing heavy metals is achieved. Diatomaceous earth, aluminate cement, modified fly ash and kaolin are used in the thermal insulation filler, which has good thermal insulation performance, and polyvinyl alcohol solution is used as a stabilizer and adhesive in the foam slurry. After the side of the board core is coated with gel and not freeze-dried, it can be pasted on the cement wall to cause physical cross-linking at the joint through the rough surface. On the surface containing organic coating, it can produce π-π stacking or hydrophobic effect through the benzene rings or long-chain alkanes contained therein, and form metal-ion coordination bonds on the metal surface, so that it is suitable for a variety of building exterior walls. In addition, because the freeze-dried gel layer has viscoelasticity, it can prevent cracking, bulging and displacement caused by deformation of the board, and has the characteristics of durability.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] An exterior wall insulation board made from fly ash from a garbage power plant, comprising the following raw materials in parts by weight:

[0006] 1-3 parts of modified nanocellulose, 100-300 parts of thermal insulation filler, 50-80 parts of dispersant, 50-80 parts of foaming agent, 10-30 parts of polyvinyl alcohol, 1-3 parts of modified fly ash, 1-3 parts of AlCl3·6H20, 100-300 parts of ethanol, 2-3 parts of 1,2-propylene oxide, 100 parts of acrylamide solution, 0.01-0.04 parts of initiator, 1-3 parts of cross-linking agent and deionized water.

[0007] Furthermore, the modified nanocellulose is prepared by the following steps:

[0008] A1. Add 0.585 g of 0.1 mol / L 2-morpholineethanesulfonic acid and 0.0876 g of 0.05 mol / L NaCl prepared with sterile deionized water to 30 mL of sterile deionized water, and adjust the pH of the system to 5.1 with NaOH solution to obtain 2-morpholineethanesulfonic acid buffer, which is set aside.

[0009] A2. Dissolve 1-3 g of nanocellulose, 0.192 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 0.115 g of N-hydroxysuccinimide, and 0.948 g of dopamine hydrochloride in 100 mL of 2-morpholineethanesulfonic acid buffer, stir thoroughly at room temperature under an inert gas atmosphere for 24 hours, and then freeze-dry in a freeze dryer to obtain modified nanocellulose.

[0010] During the above reaction process, dopamine hydrochloride is grafted onto the carboxyl groups on the nanofibers using a 1-ethyl-(3-dimethylaminopropyl)carbodiimide / NHS esterification method.

[0011] Furthermore, the mass ratio of nanocellulose to dopamine hydrochloride is (1-3): (0.5-2).

[0012] Furthermore, the thermal insulation filler is obtained by mixing diatomaceous earth, aluminate cement, modified fly ash and kaolin in a mass ratio of 80:8:7:5.

[0013] Furthermore, the modified fly ash is prepared by the following steps:

[0014] B1. Weigh 100 g of power plant fly ash, dry it in a drying oven at 105° C. for 4 hours, grind it in a rapid grinder for 30 minutes, then add deionized water to the fly ash powder at a ratio of 1:10 and stir in a magnetic stirrer to obtain a fly ash slurry;

[0015] B2. After ultrasonic treatment, the fly ash slurry is hydrothermally treated at 90° C. for 2 hours to obtain modified fly ash.

[0016] During the above reaction process, the particle size of the fly ash is reduced and unified by grinding to increase its dispersion effect; then the fly ash is treated by ultrasonic hydrothermal method to form aluminosilicate components, degrade the dioxin components therein, and seal the heavy metals.

[0017] Furthermore, in step B2, the ultrasonic treatment conditions are 240W, 35kHz, and the treatment time is 10 minutes.

[0018] Furthermore, the long-chain polymer solution is at least one of acrylamide, N-vinyl-2-pyrrolidone, and N-isopropylacrylamide, the initiator is ammonium persulfate, and the cross-linking agent is N,N'-methylenebisacrylamide.

[0019] Furthermore, the method for using the exterior wall insulation board made from fly ash from a waste power plant is as follows:

[0020] After cleaning the dust on the wall, spray the wall with 30% hydrogen peroxide solution, 50mL per square meter, then compress the insulation board at a strain rate of 10% for 0.5-1 hour, and then fix it with insulation nails, 4 insulation nails per square meter.

[0021] A method for preparing an exterior wall insulation board made from fly ash from a garbage power plant comprises the following steps:

[0022] S1. After ball-milling the insulating filler for 4 hours, the mixture was added with a dispersant and deionized water and stirred evenly to obtain a slurry; a foaming agent and 8 wt% polyvinyl alcohol were added to the slurry and stirred at 10,000 rpm for 3 minutes to obtain a foam slurry, which was then added to a mold and cured at room temperature for 4 hours, followed by demolding to obtain a green body; the green body was dried at 80°C for 12 hours, and then sintered at 1050°C for 30 minutes to obtain a board core;

[0023] S2. Add 1 g of AlCl3·6H20 to 20 mL of 80% ethanol solution and stir until uniform. Then, raise the system temperature to 50°C and stir at 30 rpm for 2 hours. Then, add 1 g of modified fly ash to the system and stir until uniform. Then, lower the system temperature to room temperature to obtain Al ion gel.

[0024] S3. Add the initiator to the long-chain polymer solution and stir at room temperature until uniform, then add the modified nanocellulose and the cross-linking agent, continue stirring until uniform, and obtain a nanocellulose cross-linked gel; mix the nanocellulose gel with the Al ion gel, add 2.5 mL of 1,2-propylene oxide, continue stirring at room temperature until uniform, and coat the gel on the board core obtained in step S1, followed by treatment at -50°C for 5 hours and freeze-drying, and then repeating the coating operation on the other side of the board core to obtain an exterior wall insulation board made of fly ash from a waste power plant.

[0025] In the above reaction process, in step S1, the heat insulating filler, foaming agent and dispersant are made into foam slurry, which is dried and sintered to obtain the board core. In step S2, AlCl3·6H20 is dissolved in deionized water. 3+ Ions form complexes with polar water molecules, and the coordinated water molecules in the system undergo -OH cleavage, generating H + Then these complexes form dimers through hydroxyl bridging or oxygen bridging to form a gel network; in step S3, 1,2-propylene oxide and Cl are then added. - The reaction forms an irreversible ring opening to form highly reactive C3H7O - Free radicals can promote Al 3+ Dissolution in Al ion gel promotes the formation of gel network, and the chain polymer formed after ring opening can produce hydrophobic interactions with the benzene ring grafted on the modified nanocellulose.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) In the technical solution of the present invention, the calcium carbonate component contained in the modified fly ash has good fluidity, is non-toxic and has no irritating odor, has high thermal stability, and can increase the temperature resistance and rigidity of the material. By replacing the traditional high-temperature technical treatment with ultrasonic hydrothermal method, the process of melting for 90 minutes in high-temperature treatment is replaced by high-energy ultrasonic treatment for ten minutes, thereby achieving the degradation of dioxins and promoting the phase change of Al2O3 and SiO2 substances in the fly ash to form a cage-like solidified substance, which plays a bridging role and seals the heavy metals therein, thereby achieving the fixation of heavy metals. And due to the change of its crystal phase, the metastable γ-Al2O3 will not be Cl in the AlCl3 system. - and OH - Nucleophilic substitution allows it to exist stably in Al ion gel.

[0028] (2) In the technical solution of the present invention, diatomaceous earth, aluminate cement, modified fly ash and kaolin materials are used in the thermal insulation filler, which has good thermal insulation performance. Polyvinyl alcohol solution is used as a stabilizer and adhesive in the foam slurry. The kaolin component can reduce the surface energy of the bubbles in the foam slurry and improve the stability of the foam. After sintering, a board core with rich pores is formed. When the gel is used to coat the board core, the metal oxides contained in the fly ash in the board core will form ionic coordination bonds with the catechol on the modified nanocellulose in the gel. In addition, the porous fly ash and diatomaceous earth can trigger the physical cross-linking of the polymer to form a new network with topological entanglement with the pre-existing network, so that the gel and the board core have better bonding strength. After freeze-drying, the coordination bond still exists as a special covalent bond.

[0029] (3) In the technical solution of the present invention, the side of the board core that is not freeze-dried after being coated with gel can cause physical cross-linking at the joint through the rough surface when pasted on the cement wall. On the surface containing organic coatings, π-π stacking or hydrophobic effect can be generated through the benzene rings or long-chain alkanes contained therein, and metal-ion coordination bonds can be formed on the metal surface, so that it is suitable for various building exterior walls. In addition, since the freeze-dried gel layer has viscoelasticity, it can prevent cracking, bulging and displacement caused by deformation of the board. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0031] The reagents used in the following examples and comparative examples are all reagent grade. The cellulose nanofibers are provided by Xidian Testing, with CAS number 9004-34-6 and a carboxyl content of 1.2-3.0 mmol / g. The dispersant is sodium lauryl sulfate, and the foaming agent is sodium rosinate. The main components of the collected power plant fly ash are 53.4% ​​SiO2, 36% Al2O3, 4.1% Fe2O3, 1.38% CaO, 0.96% MgO and other impurities.

[0032] Example 1

[0033] Modified nanocellulose is prepared by the following steps:

[0034] A1. Add 0.585 g of 0.1 mol / L 2-morpholineethanesulfonic acid and 0.0876 g of 0.05 mol / L NaCl prepared with sterile deionized water to 30 mL of sterile deionized water, and adjust the pH of the system to 5.1 with NaOH solution to obtain 2-morpholineethanesulfonic acid buffer, which is set aside.

[0035] A2. Dissolve 1 g of nanocellulose, 0.192 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 0.115 g of N-hydroxysuccinimide, and 0.948 g of dopamine hydrochloride in 100 mL of 2-morpholineethanesulfonic acid buffer, stir thoroughly at room temperature under an inert gas atmosphere for 24 hours, and then freeze-dry in a freeze dryer to obtain modified nanocellulose.

[0036] Example 2

[0037] The difference between this embodiment and embodiment 1 is that the amount of nanocellulose used in step A2 is 2 g.

[0038] Example 3

[0039] The difference between this embodiment and embodiment 1 is that the amount of nanocellulose used in step A2 is 3 g.

[0040] Example 4

[0041] Modified fly ash is prepared by the following steps:

[0042] B1. Weigh 100 g of power plant fly ash, dry it in a drying oven at 105° C. for 4 hours, grind it in a rapid grinder for 30 minutes, then mix the fly ash powder with 1 L of deionized water and stir it in a magnetic stirrer to obtain a fly ash slurry;

[0043] B2. The fly ash slurry was subjected to ultrasonic treatment at 240W, 35kHz, and a treatment time of 10 minutes, followed by hydrothermal treatment at 90°C for 2 hours to obtain modified fly ash.

[0044] Example 5

[0045] An exterior wall insulation board made from fly ash from a garbage power plant, comprising the following raw materials in parts by weight:

[0046] 1 g modified nanocellulose, 100 g thermal insulation filler, 50 g dispersant, 50 g foaming agent, 10 g 8% polyvinyl alcohol solution, 1 g modified fly ash, 1 g AlCl3·6H20, 100 g ethanol, 2 g 1,2-propylene oxide, 100 g acrylamide solution, 0.01 g initiator, 1 g cross-linking agent, phenolic resin and deionized water.

[0047] A method for preparing an exterior wall insulation board made from fly ash from a garbage power plant comprises the following steps:

[0048] S1. Diatomaceous earth, aluminate cement, modified fly ash and kaolin are mixed in a mass ratio of 80:8:7:5 to obtain a thermal insulation filler; after ball-milling the raw thermal insulation filler by mass for 4 hours, 50g of dispersant and 100g of deionized water are added and stirred evenly to obtain a slurry; a foaming agent and 8wt% of polyvinyl alcohol are added to the slurry, and stirred at a speed of 10000rpm for 3 minutes to obtain a foam slurry, and then the foam slurry is added to a 50cm*50cm*3cm mold and cured at room temperature for 4 hours, and then demolded to obtain a green body; the green body is dried at 80°C for 12 hours, and then sintered at 1050°C for 30 minutes to obtain a board core;

[0049] S2. Add AlCl3·6H20 to 200 g of 80% ethanol solution and stir until uniform. Then, raise the system temperature to 50°C and stir at 30 rpm for 2 hours. Then, add the modified fly ash to the system and stir until uniform. Then, lower the system temperature to room temperature to obtain Al ion gel.

[0050] S3. Add acrylamide to sterile deionized water and stir evenly to obtain an acrylamide solution, add an initiator to the acrylamide solution and stir until uniform, then add modified nanocellulose and 1g of a cross-linking agent, continue stirring until uniform, and obtain a nanocellulose cross-linked gel; mix the nanocellulose gel with the Al ion gel, add 1,2-propylene oxide, continue stirring at room temperature until uniform, and coat the gel on the board core obtained in step S1 with a coating thickness of 1 cm, then treat at -50°C for 5 hours and then freeze-dry, and then repeat the coating operation on the other side of the board core to obtain an exterior wall insulation board made of fly ash from a waste power plant.

[0051] Example 6

[0052] The difference between this embodiment and embodiment 5 is that an exterior wall insulation board made of fly ash from a waste power plant comprises the following raw materials in parts by weight:

[0053] 2 g modified nanocellulose, 200 g thermal insulation filler, 65 g dispersant, 65 g foaming agent, 20 g polyvinyl alcohol, 2 g modified fly ash, 2 g AlCl3·6H20, 200 g ethanol, 2.5 g 1,2-propylene oxide, 100 g acrylamide solution, 0.027 mg initiator, 2 g cross-linking agent and deionized water.

[0054] Example 7

[0055] The difference between this embodiment and embodiment 5 is that N-isopropylacrylamide solution is used instead of acrylamide solution.

[0056] Example 8

[0057] The difference between this embodiment and embodiment 5 is that an exterior wall insulation board made of fly ash from a waste power plant comprises the following raw materials in parts by weight:

[0058] 3 g modified nanocellulose, 300 g thermal insulation filler, 80 g dispersant, 80 g foaming agent, 30 g polyvinyl alcohol, 3 g modified fly ash, 3 g AlCl3·6H20, 300 g ethanol, 3 g 1,2-propylene oxide, 100 g acrylamide solution, 0.04 g initiator, 3 g cross-linking agent and deionized water.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 6 is that the power plant fly ash is not modified.

[0061] Comparative Example 2

[0062] The difference between this comparative example and Example 6 is that no Al ion gel is added.

[0063] Comparative Example 3

[0064] The difference between this comparative example and Example 6 is that a wooden board is used instead of a core board.

[0065] The insulation boards prepared in Examples 5-8 and Comparative Examples 1-3 were tested for thermal insulation performance. Thermal insulation performance testing was performed according to GB / T10294-2008, and flame retardancy testing was performed according to GB / T5464-2010. Five readings were taken for each sample and the average value was calculated. The test results are shown in Table 1 below.

[0066] Table 1 Thermal insulation performance test of the thermal insulation boards prepared in Examples 5-8 and Comparative Examples 1-3

[0067] project Thermal conductivity W / (mK) Oxygen index / % Example 5 0.016 35.3 Example 6 0.013 36.8 Example 7 0.018 35.2 Example 8 0.016 35.3 Comparative Example 1 0.020 16.3 Comparative Example 2 0.039 16.0 Comparative Example 3 0.268 13.1

[0068] As shown in Table 1 above, the insulation board prepared in Example 6 has the best thermal insulation performance. The results in Comparative Example 2 show that the multi-crosslinked gel system formed by the Al ion gel and the polymer gel can enhance the thermal insulation effect of the finished board. The results in Comparative Example 3 show that the insulation effect of the insulation board can be improved by replacing the wood board in the traditional board with a board core made of thermal insulating filler.

[0069] The thermal insulation boards prepared in Examples 5-8 and Comparative Examples 1-3 were subjected to mechanical property tests according to GB / T 1935-2009. Five readings were taken for each sample and the average value was calculated. The test results are shown in Table 2 below.

[0070] Table 2 Mechanical properties test of the insulation boards prepared in Examples 5-8 and Comparative Examples 1-3

[0071] project Compressive strength / MPa Bending strength / MPa Example 5 23.3 22.0 Example 6 23.5 22.6 Example 7 23.2 22.3 Example 8 23.3 22.1 Comparative Example 1 20.9 18.9 Comparative Example 2 19.5 18.0 Comparative Example 3 16.3 16.9

[0072] The results in Table 2 show that the insulation boards prepared in Examples 5-8 have improved compressive and flexural strength. The results in Comparative Example 1 show that the modified fly ash used as the board core and gel filler can increase the material's mechanical strength. The results in Comparative Example 2 show that the multi-crosslinked gel network composed of the Al ion gel can increase the board's compressive and flexural strength.

[0073] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0074] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing an exterior wall insulation board made from fly ash from a garbage power plant, characterized in that: The exterior wall insulation board comprises the following raw materials in parts by weight: 1-3 parts of modified nanocellulose, 100-300 parts of thermal insulation filler, 50-80 parts of dispersant, 50-80 parts of foaming agent, 10-30 parts of polyvinyl alcohol, 1-3 parts of modified fly ash, 1-3 parts of AlCl3∙6H20, 100-300 parts of ethanol, 2-3 parts of 1,2-propylene oxide, 100 parts of acrylamide solution, 0.01-0.04 parts of initiator, 1-3 parts of cross-linking agent and deionized water; The preparation method comprises the following steps: S1. After ball-milling the thermal insulation filler for 4 hours, the mixture was added with a dispersant and deionized water and stirred evenly to obtain a slurry; a foaming agent and polyvinyl alcohol were added to the slurry and stirred at a rate of 10,000 rpm for 3 minutes to obtain a foam slurry, which was then added to a mold and cured at room temperature for 4 hours, followed by demolding to obtain a green body; the green body was dried at 80°C for 12 hours, and then sintered at 1050°C for 30 minutes to obtain a board core; S2. AlCl3∙6H20 was added to the ethanol solution and stirred until uniform. The system temperature was then raised to 50°C and stirred at 30 rpm for 2 hours. The modified fly ash was then added to the system and stirred until uniform. The system temperature was then lowered to room temperature to obtain Al ion gel. S3, adding an initiator to the acrylamide solution at room temperature and stirring until uniform, then adding modified nanocellulose and a crosslinking agent, and continuing to stir until uniform, to obtain a nanocellulose crosslinked gel; mixing the nanocellulose gel with the Al ion gel, adding 1,2-propylene oxide, and continuing to stir at room temperature until uniform, coating the nanocellulose gel on the board core obtained in step S1, and then treating the board core at -50°C for 5 hours and then freeze-drying the board core, and then repeating the coating operation on the other side of the board core to obtain an exterior wall insulation board made of fly ash from a waste power plant; The modified nanocellulose is prepared by the following steps: A1. Add 2-morpholineethanesulfonic acid NaCl to sterile deionized water, and use NaOH solution to adjust the system pH to 5.1 to obtain 2-morpholineethanesulfonic acid buffer, which is set aside. A2, dissolving nanocellulose, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, N-hydroxysuccinimide and dopamine hydrochloride in 2-morpholineethanesulfonic acid buffer, stirring at room temperature under an inert gas atmosphere, and then freeze-drying to obtain modified nanocellulose; The modified fly ash is prepared by the following steps: B1. Weigh fly ash from a power plant, dry it in a drying oven at 105°C for 4 hours, grind it in a rapid grinder for 30 minutes, then add deionized water to the fly ash powder at a ratio of 1:10 and stir in a magnetic stirrer to obtain a fly ash slurry; B2, subjecting the fly ash slurry to ultrasonic treatment and then hydrothermally treating it at 90° C. for 2 hours to obtain modified fly ash; The heat-insulating filler is obtained by mixing diatomaceous earth, aluminate cement, modified fly ash and kaolin.

2. The preparation method according to claim 1, characterized in that The mass ratio of nanocellulose to dopamine hydrochloride is (1-3):(0.5-2).

3. The preparation method according to claim 1, characterized in that In step B2, the ultrasonic treatment conditions were 240 W, 35 kHz, and the treatment time was 10 minutes.

4. The preparation method according to claim 1, characterized in that The thermal insulation filler is obtained by mixing diatomaceous earth, aluminate cement, modified fly ash and kaolin in a mass ratio of 80:8:7:

5.

5. The preparation method according to claim 1, characterized in that The initiator is ammonium persulfate, and the cross-linking agent is N,N'-methylenebisacrylamide.

6. The preparation method according to claim 1, characterized in that The method of using the exterior wall insulation board is to clean the dust on the wall, spray the wall with hydrogen peroxide solution, then compress the insulation board at a strain rate of 10% for 0.5-1 hour, and then fix it with insulation nails, with 4 insulation nails used per square meter.