Aerated concrete produced using solid waste and a method for producing the same

Abstract

This invention discloses an aerated concrete production method utilizing solid waste and its manufacturing process in the field of aerated concrete technology. The invention prepares a modified foam stabilizer in which surfactant molecules intercalate into the interlayer space of liquid hydrogen peroxide (LDHs), transforming the disordered arrangement of surfactant molecules into an ordered one. This reduces the attraction between water molecules and, simultaneously, interacts with the compressed electric double layer of LDHs, lowering the surface tension of water and preventing bubble coarsening. The combination of polysaccharides with two surfactants enhances viscosity and delays bubble coarsening. This modified foam stabilizer facilitates bubble formation, resulting in more rounded, numerous, smaller, and more uniformly distributed bubbles, maintaining the lightweight, high-strength, and excellent thermal insulation properties of the aerated concrete. LDHs can adsorb and fix corrosive ions such as chloride ions, reducing corrosion of the aerated concrete and improving the product's weather resistance and waterproofing. Using industrial solid waste as raw material reduces raw material costs and achieves sustainable resource utilization and energy conservation and emission reduction.

Description

Technical Field

[0001] This invention belongs to the field of aerated concrete technology, and particularly relates to an aerated concrete produced using solid waste and its production method. Background Technology

[0002] Autoclaved aerated concrete (AAC) is a lightweight building material composed of mineral aggregates (such as sand), cement, lime, water, and a foaming agent. When these components are mixed, the foaming agent generates tiny air bubbles, causing the concrete to expand and form a porous structure. The concrete is then cut into the desired shape and cured in a high-pressure steam environment to improve its strength and durability. AAC possesses excellent thermal insulation, fire resistance, and earthquake resistance properties. Its lightweight nature also reduces the self-weight of building structures and lowers foundation costs. It is widely used for walls, floors, roofs, and partitions in residential, commercial, and industrial buildings. Utilizing industrial solid waste to produce AAC is an important manifestation of sustainable development and the circular economy concept in the building materials field. With increasing global attention to environmental protection and resource conservation, converting industrial byproducts or waste into useful building materials has become a significant trend. This practice not only reduces the exploitation of natural resources but also helps mitigate the environmental impact of industrial waste.

[0003] Ideally, aerated concrete should have uniformly small air bubbles, which contributes to better thermal insulation and higher compressive strength. However, if the foaming agent is not added and mixed evenly, or if the proportioning and mixing process are improper, it can lead to bubbles of varying sizes, or even the formation of larger pores. During the concrete setting process, these bubbles are highly likely to merge, forming large cavities, which weakens the structural strength and durability of the material. The uniform distribution of air bubbles is crucial for the structural integrity and mechanical properties of aerated concrete. If the pouring, mixing, or curing process is not properly controlled, bubbles may aggregate in certain areas, affecting the quality of the aerated concrete. Furthermore, due to its porosity, aerated concrete often has lower resistance to permeability and chloride ion attack than dense ordinary concrete. Therefore, optimizing the material proportions and improving the manufacturing process are essential to enhancing the mechanical properties, porosity consistency, permeability resistance, and chloride ion attack resistance of aerated concrete. Summary of the Invention

[0004] To address the above issues and overcome the shortcomings of existing technologies, this invention provides aerated concrete produced using solid waste and its production method. To solve the problem of uneven pore distribution in aerated concrete and to maintain its lightweight, high strength, and good thermal insulation properties, this invention provides a modified foam stabilizer and a production method for aerated concrete produced using solid waste.

[0005] To achieve the above objectives, the following technical solution is adopted: This invention provides an aerated concrete produced using solid waste and its production method. The aerated concrete produced using solid waste comprises the following components in parts by weight: 70-100 parts cement, 50-80 parts tailings, 30-50 parts lime, 20-40 parts gypsum, 300-500 parts water, 10-20 parts aluminum powder, 2-8 parts modified foam stabilizer, and 1-5 parts water-reducing agent.

[0006] Further, the modified foam stabilizer is prepared by the following steps: aqueous solutions of divalent and trivalent metal salts with the same concentration of 0.5-1 mol / L are prepared separately; the aqueous solutions of the divalent and trivalent metal salts are mixed evenly at a volume ratio of 3:1; a 0.8-1 mol / L alkaline source solution is slowly added dropwise while stirring; the pH is adjusted to 9-11; the mixture is continuously stirred at 60-100℃ for 3-5 hours; after the reaction is completed, the mixture is cooled to room temperature, filtered, and the precipitate is separated; the precipitate is washed with distilled water to obtain LDHs; 4-10 parts of FS-50 amphoteric surfactant, 5-10 parts of anionic surfactant, 5-8 parts of polysaccharide, and 50-80 parts of water are mixed and stirred; 1-3 parts of the LDHs are added; the mixture is stirred at room temperature for 4-6 hours to obtain the modified foam stabilizer.

[0007] Furthermore, the divalent metal salt is one of the chlorides, sulfates, or nitrates of magnesium, calcium, ferrous, copper, nickel, or zinc ions, and the trivalent metal salt is one of the chlorides, sulfates, or nitrates of iron or aluminum.

[0008] Furthermore, the alkaline source solution is one of sodium hydroxide or potassium hydroxide solution.

[0009] Furthermore, the anionic surfactant is one of disodium lauryl citrate sulfosuccinate, sodium diethylhexyl sulfosuccinate, and disodium cocoyl monoethanolamide sulfosuccinate.

[0010] Furthermore, the polysaccharide is one of galactomannan, glucomannan, konjac mannan, or polydextrose.

[0011] Furthermore, the tailings are one or more of copper mine tailings, iron mine tailings, and titanium mine tailings.

[0012] Furthermore, the gypsum is one of the following: flue gas desulfurization gypsum, phosphogypsum, fluorogypsum, titanium gypsum, copper gypsum, nickel gypsum, chromium gypsum, and boron gypsum.

[0013] Furthermore, the water-reducing agent is one of sodium polynaphthalene sulfonate, disodium methylene dinaphthalene sulfonate, and sodium diisobutylnaphthalene sulfonate.

[0014] Furthermore, the method for producing aerated concrete using solid waste includes the following steps:

[0015] (1) Crushing: The tailings are crushed into fine powder by crushing equipment and dried to obtain tailings powder;

[0016] (2) Mixing: Add the tailings powder, lime, cement and gypsum to a ball mill and mix evenly, then add the water and stir to form a uniform slurry;

[0017] (3) Gas generation: The aluminum powder is added to the uniform slurry as a gas generator, and then the modified foam stabilizer and water-reducing agent are added. The reaction generates hydrogen gas, which causes the concrete to expand. The gas generation takes 15-40 minutes to obtain a mixed slurry.

[0018] (4) Pouring: Quickly pour the mixed slurry into the mold to make the air bubbles evenly distributed and begin to set. Let it stand for 4-10 hours to obtain the initial set concrete.

[0019] (5) Cutting: Use a cutting machine to cut the initial set concrete into blanks;

[0020] (6) High-pressure steam curing: The green body is placed into a high-pressure steam curing kettle and steamed at high temperature and high pressure for 12-24 hours at a temperature of 130-150℃ and a pressure of 0.8-1.2MPa.

[0021] (7) Demolding and curing: After steam curing, the aerated concrete produced using solid waste is obtained by letting it stand at room temperature for 12-24 hours after demolding.

[0022] The beneficial effects of this invention are:

[0023] (1) The present invention first prepared a modified foam stabilizer for preparing aerated concrete. In the modified foam stabilizer, surfactant molecules enter the interlayer space of LDHs through intercalation. The layered structure of LDHs restricts the arrangement of surfactant molecules, making the disordered arrangement of surfactant molecules become ordered. The hydrophobic tail of the surfactant extends away from the water and towards the air, while the hydrophilic head remains in the water. This arrangement reduces the attraction between water molecules. The hydrophobic tail forms a barrier, which works simultaneously with the compressed electric double layer of LDHs to reduce the surface tension of water. The layered structure of LDHs and the ordered arrangement of surfactants also form a barrier to the diffusion of gas molecules, slowing down the diffusion process of small bubbles to large bubbles and preventing the bubbles from coarsening.

[0024] (2) The polysaccharides added to this modified foam stabilizer are used in combination with two surfactants, which can significantly enhance viscosity, delay the coarsening of bubbles, reduce the segregation and bleeding of concrete slurry, and adsorb together with surfactant molecules at the air-water interface, reducing interfacial tension and improving emulsification effect. This modified foam stabilizer makes it easier for bubbles to form, makes them rounder, more numerous, smaller in size and more evenly distributed, which can help aerated concrete maintain its lightweight, high strength and good thermal insulation properties.

[0025] (3) In actual use, aerated concrete is easily corroded by anions, especially chloride ions. LDHs, due to their layered structure and exchangeable anions, have the ability to adsorb anions. Therefore, they can adsorb and fix corrosive ions such as chloride ions to reduce the corrosive effect on aerated concrete and its internal steel bars, and improve the weather resistance and waterproofness of aerated concrete.

[0026] (4) The tailings, lime and gypsum in the raw materials of the aerated concrete are industrial solid wastes. By recycling them, the cost of raw materials is reduced, the demand for natural resources is reduced, which helps the sustainable use of resources and also achieves energy conservation and emission reduction. Attached Figure Description

[0027] Figure 1 This is a flowchart of a method for producing aerated concrete using solid waste according to the present invention.

[0028] Figure 2 The results show the oven-dry density of the aerated concrete prepared in the various embodiments and comparative examples of this invention.

[0029] Figure 3 The compressive strength test results are for the aerated concrete prepared in the various embodiments and comparative examples of this invention.

[0030] Figure 4 The results show the thermal conductivity of the aerated concrete prepared in the various embodiments and comparative examples of this invention.

[0031] Figure 5 The porosity test results are for the aerated concrete prepared in the various embodiments and comparative examples of this invention.

[0032] Figure 6 The results show the chloride ion diffusion coefficient of the aerated concrete prepared in the various embodiments and comparative examples of this invention.

[0033] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the experimental materials used in the following examples are all purchased from commercial channels.

[0037] Example 1

[0038] A method for producing aerated concrete using solid waste.

[0039] The aerated concrete produced using solid waste comprises the following components by weight: 70 parts cement, 50 parts tailings, 30 parts lime, 20 parts gypsum, 300 parts water, 10 parts aluminum powder, 2 parts modified foam stabilizer, and 1 part water-reducing agent.

[0040] The modified foam stabilizer is prepared by the following steps: aqueous solutions of divalent and trivalent metal salts with the same concentration of 0.5 mol / L are prepared separately. The aqueous solutions of the divalent and trivalent metal salts are mixed evenly at a volume ratio of 3:1. A 0.8 mol / L alkaline source solution is slowly added dropwise while stirring to adjust the pH to 9. The mixture is stirred continuously at 60°C for 3 hours. After the reaction is completed, the mixture is cooled to room temperature, filtered, and the precipitate is separated. The precipitate is washed with distilled water to obtain LDHs. Four parts of FS-50 amphoteric surfactant, five parts of anionic surfactant, five parts of polysaccharide, and 50 parts of water are mixed and stirred. One part of the LDHs is added, and the mixture is stirred at room temperature for 4 hours to obtain the modified foam stabilizer.

[0041] The divalent metal salt is magnesium chloride.

[0042] The trivalent metal salt is ferric chloride.

[0043] The alkaline source solution is a sodium hydroxide solution.

[0044] The anionic surfactant is disodium lauryl citrate sulfosuccinate.

[0045] The polysaccharide is galactomannan.

[0046] The tailings are copper mine tailings.

[0047] The gypsum is flue gas desulfurization gypsum.

[0048] The water-reducing agent is sodium polynaphthalene sulfonate.

[0049] The method for producing aerated concrete using solid waste includes the following steps:

[0050] (1) Crushing: The tailings are crushed into fine powder by crushing equipment and dried to obtain tailings powder;

[0051] (2) Mixing: Add the tailings powder, lime, cement and gypsum to a ball mill and mix evenly, then add the water and stir to form a uniform slurry;

[0052] (3) Gas generation: The aluminum powder is added to the uniform slurry as a gas generator, and then the modified foam stabilizer and water-reducing agent are added. The reaction generates hydrogen gas, which causes the concrete to expand. The gas generation is carried out for 15 minutes to obtain the mixed slurry.

[0053] (4) Pouring: Quickly pour the mixed slurry into the mold to make the air bubbles evenly distributed and begin to set. Let it stand for 4 hours to obtain the initial set concrete.

[0054] (5) Cutting: Use a cutting machine to cut the initial set concrete into blanks;

[0055] (6) High-pressure steam curing: The blank is placed into a high-pressure steam curing kettle and steamed at high temperature and high pressure for 12 hours at a temperature of 130℃ and a pressure of 0.8MPa.

[0056] (7) Demolding and curing: After steam curing, the aerated concrete produced by solid waste is obtained by letting it stand at room temperature for 12 hours after demolding.

[0057] Example 2

[0058] A method for producing aerated concrete using solid waste.

[0059] The aerated concrete produced using solid waste comprises the following components by weight: 100 parts cement, 80 parts tailings, 50 parts lime, 40 parts gypsum, 500 parts water, 20 parts aluminum powder, 8 parts modified foam stabilizer, and 5 parts water-reducing agent.

[0060] The modified foam stabilizer is prepared by the following steps: aqueous solutions of divalent and trivalent metal salts with the same concentration of 1 mol / L are prepared separately. The aqueous solutions of the divalent and trivalent metal salts are mixed evenly at a volume ratio of 3:1. A 1 mol / L alkaline source solution is slowly added dropwise while stirring to adjust the pH to 11. The mixture is stirred continuously at 100°C for 5 hours. After the reaction is completed, the mixture is cooled to room temperature, filtered, and the precipitate is separated. The precipitate is washed with distilled water to obtain LDHs. 10 parts of FS-50 amphoteric surfactant, 10 parts of anionic surfactant, 8 parts of polysaccharide, and 80 parts of water are mixed and stirred. 3 parts of the LDHs are added, and the mixture is stirred at room temperature for 6 hours to obtain the modified foam stabilizer.

[0061] The divalent metal salt is zinc sulfate.

[0062] The trivalent metal salt is aluminum sulfate.

[0063] The alkaline source solution is a potassium hydroxide solution.

[0064] The anionic surfactant is sodium diethylhexyl sulfosuccinate.

[0065] The polysaccharide is glucomannan.

[0066] The tailings are a combination of iron ore tailings and titanium ore tailings in a 1:1 mass ratio.

[0067] The gypsum is phosphogypsum.

[0068] The water-reducing agent is disodium methylene dinaphthalene sulfonate.

[0069] The method for producing aerated concrete using solid waste includes the following steps:

[0070] (1) Crushing: The tailings are crushed into fine powder by crushing equipment and dried to obtain tailings powder;

[0071] (2) Mixing: Add the tailings powder, lime, cement and gypsum to a ball mill and mix evenly, then add the water and stir to form a uniform slurry;

[0072] (3) Gas generation: The aluminum powder is added to the uniform slurry as a gas generator, and then the modified foam stabilizer and water-reducing agent are added. The reaction generates hydrogen gas, which causes the concrete to expand. The gas generation time is 40 minutes, and a mixed slurry is obtained.

[0073] (4) Pouring: Quickly pour the mixed slurry into the mold to make the air bubbles evenly distributed and begin to set. Let it stand for 10 hours to obtain the initial set concrete.

[0074] (5) Cutting: Use a cutting machine to cut the initial set concrete into blanks;

[0075] (6) High-pressure steam curing: The blank is placed into a high-pressure steam curing kettle and steamed at high temperature and high pressure for 24 hours at a temperature of 150℃ and a pressure of 1.2MPa.

[0076] (7) Demolding and curing: After steam curing, the aerated concrete produced by solid waste is obtained by letting it stand at room temperature for 24 hours after demolding.

[0077] Example 3

[0078] A method for producing aerated concrete using solid waste.

[0079] The aerated concrete produced using solid waste comprises the following components by weight: 80 parts cement, 60 parts tailings, 40 parts lime, 30 parts gypsum, 400 parts water, 15 parts aluminum powder, 6 parts modified foam stabilizer, and 4 parts water-reducing agent.

[0080] The modified foam stabilizer is prepared by the following steps: aqueous solutions of divalent and trivalent metal salts with the same concentration of 0.7 mol / L are prepared separately. The aqueous solutions of the divalent and trivalent metal salts are mixed evenly at a volume ratio of 3:1. A 0.9 mol / L alkaline source solution is slowly added dropwise while stirring to adjust the pH to 10. The mixture is stirred continuously at 80°C for 4 hours. After the reaction is completed, the mixture is cooled to room temperature, filtered, and the precipitate is separated. The precipitate is washed with distilled water to obtain LDHs. Seven parts of FS-50 amphoteric surfactant, eight parts of anionic surfactant, six parts of polysaccharide, and 75 parts of water are mixed and stirred. Two parts of the LDHs are added, and the mixture is stirred at room temperature for 5 hours to obtain the modified foam stabilizer.

[0081] The divalent metal salt is ferrous nitrate.

[0082] The trivalent metal salt is ferric nitrate.

[0083] The alkaline source solution is a sodium hydroxide solution.

[0084] The anionic surfactant is disodium cocoyl ethanolamide sulfosuccinate monoester.

[0085] The polysaccharide is konjac mannan.

[0086] The tailings are titanium ore tailings.

[0087] The gypsum is fluorinated gypsum.

[0088] The water-reducing agent is sodium diisobutylnaphthalene sulfonate.

[0089] The method for producing aerated concrete using solid waste includes the following steps:

[0090] (1) Crushing: The tailings are crushed into fine powder by crushing equipment and dried to obtain tailings powder;

[0091] (2) Mixing: Add the tailings powder, lime, cement and gypsum to a ball mill and mix evenly, then add the water and stir to form a uniform slurry;

[0092] (3) Gas generation: The aluminum powder is added to the uniform slurry as a gas generator, and then the modified foam stabilizer and water-reducing agent are added. The reaction generates hydrogen gas, which causes the concrete to expand. The gas generation is carried out for 30 minutes to obtain the mixed slurry.

[0093] (4) Pouring: Quickly pour the mixed slurry into the mold to make the air bubbles evenly distributed and begin to set. Let it stand for 6 hours to obtain the initial set concrete.

[0094] (5) Cutting: Use a cutting machine to cut the initial set concrete into blanks;

[0095] (6) High-pressure steam curing: The blank is placed into a high-pressure steam curing kettle and steamed at high temperature and high pressure for 18 hours at a temperature of 140℃ and a pressure of 1.0MPa.

[0096] (7) Demolding and curing: After steam curing, the aerated concrete produced by solid waste is obtained by letting it stand at room temperature for 18 hours after demolding.

[0097] Example 4

[0098] A method for producing aerated concrete using solid waste.

[0099] The aerated concrete produced using solid waste comprises the following components by weight: 80 parts cement, 60 parts tailings, 30 parts lime, 25 parts gypsum, 350 parts water, 15 parts aluminum powder, 6 parts modified foam stabilizer, and 4 parts water-reducing agent.

[0100] The modified foam stabilizer is prepared by the following steps: aqueous solutions of divalent and trivalent metal salts with the same concentration of 0.8 mol / L are prepared separately. The aqueous solutions of the divalent and trivalent metal salts are mixed evenly at a volume ratio of 3:1. A 0.8 mol / L alkaline source solution is slowly added dropwise while stirring to adjust the pH to 9.5. The mixture is stirred continuously at 180°C for 4 hours. After the reaction is complete, the mixture is cooled to room temperature, filtered, and the precipitate is separated. The precipitate is washed with distilled water to obtain LDHs. Eight parts of FS-50 amphoteric surfactant, eight parts of anionic surfactant, six parts of polysaccharide, and 70 parts of water are mixed and stirred. 1.5 parts of the LDHs are added, and the mixture is stirred at room temperature for 4.5 hours to obtain the modified foam stabilizer.

[0101] The divalent metal salt is zinc chloride.

[0102] The trivalent metal salt is aluminum chloride.

[0103] The alkaline source solution is potassium hydroxide solution.

[0104] The anionic surfactant is disodium lauryl citrate sulfosuccinate.

[0105] The polysaccharide is polydextrose.

[0106] The tailings are a combination of copper tailings, iron tailings, and titanium tailings in a 3:1:1 ratio.

[0107] The gypsum is titanium gypsum.

[0108] The water-reducing agent is disodium methylene dinaphthalene sulfonate.

[0109] The method for producing aerated concrete using solid waste includes the following steps:

[0110] (1) Crushing: The tailings are crushed into fine powder by crushing equipment and dried to obtain tailings powder;

[0111] (2) Mixing: Add the tailings powder, lime, cement and gypsum to a ball mill and mix evenly, then add the water and stir to form a uniform slurry;

[0112] (3) Gas generation: The aluminum powder is added to the uniform slurry as a gas generator, and then the modified foam stabilizer and water-reducing agent are added. The reaction generates hydrogen gas, which causes the concrete to expand. The gas generation is carried out for 30 minutes to obtain the mixed slurry.

[0113] (4) Pouring: Quickly pour the mixed slurry into the mold to make the air bubbles evenly distributed and begin to set. Let it stand for 8 hours to obtain the initial set concrete.

[0114] (5) Cutting: Use a cutting machine to cut the initial set concrete into blanks;

[0115] (6) High-pressure steam curing: The blank is placed into a high-pressure steam curing kettle and steamed at high temperature and high pressure for 15 hours at a temperature of 130℃ and a pressure of 0.8MPa.

[0116] (7) Demolding and curing: After steam curing, the aerated concrete produced by solid waste is obtained by letting it stand at room temperature for 20 hours after demolding.

[0117] Comparative Example 1

[0118] A method for producing aerated concrete using solid waste.

[0119] The difference between this comparative example and Example 1 is that the modified foam stabilizer does not contain LDHs but is replaced by an equal amount of water. The remaining components, component contents, and preparation process steps are the same as in Example 1.

[0120] Comparative Example 2

[0121] A method for producing aerated concrete using solid waste.

[0122] The difference between this comparative example and Example 1 is that the modified foam stabilizer does not contain polysaccharides but is replaced by an equal amount of water. The remaining components, component contents, and preparation process steps are the same as in Example 1.

[0123] Comparative Example 3

[0124] A method for producing aerated concrete using solid waste.

[0125] The difference between this comparative example and Example 1 is that the modified foam stabilizer does not contain FS-50 amphoteric surfactant but is replaced by an equal amount of water. The remaining components, component content, and preparation process steps are the same as in Example 1.

[0126] Comparative Example 4

[0127] A method for producing aerated concrete using solid waste.

[0128] The difference between this comparative example and Example 1 is that the modified foam stabilizer does not contain anionic surfactants but is replaced by an equal amount of water. The remaining components, component contents, and preparation process steps are the same as in Example 1.

[0129] Results Analysis

[0130] The oven-dry density and compressive strength of the aerated concrete prepared in each embodiment and comparative example of this invention were determined according to the test methods in GB / T 11969-2020 "Test Methods for Performance of Autoclaved Aerated Concrete". The test results are shown in the figures below. Figure 2 , Figure 3 .

[0131] The thermal conductivity of the aerated concrete prepared in each embodiment and comparative example of this invention was determined according to the test methods in GB 50176-2016 "Code for Thermal Design of Civil Buildings". The test results are shown below. Figure 4 .

[0132] The porosity of the aerated concrete prepared in the various embodiments and comparative examples of this invention was determined using the true and false density method. The method is as follows: the samples were cut into regular cuboids, dried, and the mass of the dried samples was weighed. The dimensions of the samples were accurately measured, and the false density ρ was obtained by dividing the mass of the sample by its external volume. O The sample is placed in a specific gravity bottle, and a known volume of alcohol is added. A vacuum is then applied to ensure the liquid fills all the pores of the sample. The total mass of the specific gravity bottle and the sample after filling with liquid is measured. The sample volume is determined by calculating the mass difference of the liquid. The true density ρ is obtained by dividing the sample mass by the sample volume. T Porosity = (1-ρ) O / ρ T ()×100%, test results are shown in Figure 5 .

[0133] The chloride ion diffusion coefficients of the aerated concrete prepared in each embodiment and comparative example of this invention were determined according to the test methods in GB / T 50082-2006 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete". The test time was 45 days. The test results are shown in [Figure number missing]. Figure 6 .

[0134] Depend on Figure 2-5 It can be seen that the aerated concrete prepared in the embodiments of the present invention still has high compressive strength, high porosity and low thermal conductivity even with low oven-dry density. This indicates that the aerated concrete prepared in the present invention has smaller pore volume and more uniform distribution, and has high strength and good thermal insulation while maintaining lightweight.

[0135] Depend on Figure 6 It can be seen that the chloride ion diffusion coefficients of each embodiment and comparative examples 2, 3, and 4 are all less than those of comparative example 1, indicating that the addition of LDHs effectively improves the chloride ion corrosion resistance of aerated concrete.

[0136] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0137] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. An aerated concrete produced using solid waste, characterized in that: The aerated concrete produced using solid waste comprises the following components by weight: 70-100 parts cement, 50-80 parts tailings, 30-50 parts lime, 20-40 parts gypsum, 300-500 parts water, 10-20 parts aluminum powder, 2-8 parts modified foam stabilizer, and 1-5 parts water-reducing agent. The modified foam stabilizer is prepared by the following steps: preparing aqueous solutions of divalent and trivalent metal salts with the same concentration of 0.5-1 mol / L, and mixing the aqueous solutions of the divalent and trivalent metal salts in a 3:1 ratio. Mix the products thoroughly, and slowly add 0.8-1 mol / L alkaline source solution dropwise while stirring to adjust the pH to 9-11. Continue stirring at 60-100℃ for 3-5 hours. After the reaction is complete, cool to room temperature, filter, separate the precipitate, wash the precipitate with distilled water to obtain LDHs. Mix 4-10 parts of FS-50 amphoteric surfactant, 5-10 parts of anionic surfactant, 5-8 parts of polysaccharide with 50-80 parts of water and stir. Add 1-3 parts of the LDHs and stir at room temperature for 4-6 hours to obtain the modified foam stabilizer. The divalent metal salt is one of the chloride, sulfate, or nitrate of magnesium, calcium, ferrous, copper, nickel, or zinc ions; The trivalent metal salt is one of the chloride, sulfate, or nitrate of iron or aluminum; The anionic surfactant is one of disodium lauryl citrate sulfosuccinate, sodium diethylhexyl sulfosuccinate, and disodium cocoyl monoethanolamide sulfosuccinate. The polysaccharide is one of galactomannan, glucomannan, konjac mannan, or polydextrose.

2. The aerated concrete produced using solid waste according to claim 1, characterized in that: The alkaline source solution is either sodium hydroxide or potassium hydroxide solution.

3. The aerated concrete produced using solid waste according to claim 2, characterized in that: The tailings are one or more of copper mine tailings, iron mine tailings, and titanium mine tailings.

4. The aerated concrete produced using solid waste according to claim 3, characterized in that: The gypsum is one of the following: flue gas desulfurization gypsum, phosphogypsum, fluorogypsum, titanium gypsum, copper gypsum, nickel gypsum, chromium gypsum, and boron gypsum.

5. The aerated concrete produced using solid waste according to claim 4, characterized in that: The water-reducing agent is one of sodium polynaphthalene sulfonate, disodium methylene dinaphthalene sulfonate, or sodium diisobutylnaphthalene sulfonate.

6. A method for producing aerated concrete using solid waste according to claim 5, characterized in that: The production method includes the following steps: (1) Crushing: The tailings are crushed into fine powder by crushing equipment and dried to obtain tailings powder; (2) Mixing: Add the tailings powder, lime, cement and gypsum to a ball mill and mix evenly. Then add the water and stir to form a uniform slurry. (3) Gas generation: The aluminum powder is added to the uniform slurry as a gas generator, and then the modified foam stabilizer and water-reducing agent are added. The reaction generates hydrogen gas, which causes the concrete to expand. The gas generation takes 15-40 minutes to obtain a mixed slurry. (4) Pouring: Quickly pour the mixed slurry into the mold to make the air bubbles evenly distributed and begin to set. Let it stand for 4-10 hours to obtain the initial set concrete. (5) Cutting: Use a cutting machine to cut the initial set concrete into blanks; (6) High-pressure steam curing: The green body is placed into a high-pressure steam curing kettle and steamed at high temperature and high pressure for 12-24 hours at a temperature of 130-150℃ and a pressure of 0.8-1.2MPa. (7) Demolding and curing: After steam curing, the aerated concrete produced by solid waste is obtained by letting it stand at room temperature for 12-24 hours after demolding.

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