Preparation method of solid waste based foam concrete

Abstract

The invention provides a preparation method of solid waste based foam concrete. According to the preparation method of the solid-waste-based foam concrete, the solid-waste-based foam concrete is prepared through synchronous carbonization stirring under the condition of variable air pressure, the method is not limited to pre-carbonization of fresh mixed concrete, the solid-waste raw materials can be pre-carbonized through the method, and therefore upgrading and optimization of the performance of the solid-waste raw materials are achieved; and thus, the concrete can better serve in concrete. Meanwhile, the problem of material mechanical property defects possibly caused by traditional uneven internal carbonization gradients can be effectively avoided. Besides, the solid-waste-based foam concrete is environment-friendly, functional and economical, is a green building material model capable of turning waste into wealth, is particularly suitable for engineering projects with high requirements for light weight, heat preservation and solid waste absorption, and has a wide future development prospect. The solid waste is combined with a pre-carbonization technology, and an efficient and low-carbon solution is provided for solid waste management through recycling, reduction and harmless treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete preparation, and particularly to a preparation method of solid waste-based foam concrete. Background Art

[0002] Cement has been around for over 200 years and is one of the most demanded building materials globally. However, due to problems such as high carbon emissions (accounting for 26% of total industrial emissions) and high energy consumption (accounting for 10% - 15% of total global industrial energy consumption) during cement manufacturing, the sustainable development of the cement industry is restricted. Among them, the utilization rates of solid wastes such as red mud, phosphogypsum, and steel slag are still relatively low, occupying a large amount of land resources. The increase in the quantity of these solid wastes poses a significant threat to water, air, and soil quality, as well as human health.

[0003] It is worth noting that industrial solid wastes (such as fly ash, slag, steel slag, red mud, etc.) and some municipal solid wastes (such as incineration ash, construction waste, etc.) are rich in components such as SiO2, Al2O3, and CaO, which are highly similar to the chemical composition of cement clinker (tricalcium silicate C3S, dicalcium silicate C2S). At the same time, these alkaline industrial solid wastes rich in calcium silicate minerals, calcium hydroxide, and magnesium oxide have the potential to convert CO2 into building products, thus achieving "treating waste with waste". The accelerated carbonation technology carbonates industrial solid waste and cement composites. The carbonation reaction consumes free CaO and Ca(OH)2 in the solid waste, generating stable CaCO3 and reducing the risk of volume expansion (such as the soundness problem of steel slag); after the recycled fine powder is carbonated, amorphous SiO2 and Al2O3 are formed on the surface, which can participate in the hydration reaction again as auxiliary cementitious materials; the solid waste-based material has a self-healing function after carbonation. For example, carbonate precipitation in microcracks can delay further deterioration. This "treating waste with waste" solution not only solves the problem of its own disposal, but also reduces the land occupation and pollution risk caused by landfill, and more importantly, achieves multiple goals of resource recycling, carbon emission reduction, and economy by replacing cement.

[0004] In addition, in traditional carbonation curing, due to the limited diffusion degree of CO2 in the hardened cement-based material, the distribution of carbonation products from the outside to the inside is uneven, ultimately resulting in the defect problem of uneven mechanical properties of the material. Therefore, it is necessary to improve the process of carbonating traditional industrial solid waste and cement composites. Summary of the Invention

[0005] In view of this, the preparation method of the solid waste-based foam concrete of the present invention synchronously carbonates and stirs to prepare the solid waste-based foam concrete under variable air pressure conditions, which can solve problems such as uneven mechanical properties caused by internal carbonation gradient, weak performance of solid waste materials, and synchronous carbonation stirring under non-variable pressure conditions.

[0006] To achieve the above object, the present invention provides a method for preparing solid waste-based foam concrete, comprising the following steps:

[0007] Provide a stirring device;

[0008] Add water, solid waste powder, and cement into the stirring device for pre-stirring;

[0009] After the pre-stirring is completed, evacuate the stirring device, and then introduce CO2 into the stirring device for carbonization stirring;

[0010] Mix the foaming agent with water to obtain a foaming liquid;

[0011] Add the foaming liquid into a foaming machine for foaming to obtain foam;

[0012] After the carbonization stirring is completed, relieve the pressure to discharge the CO2 in the stirring device, and then add the foam into the stirring device and stir again to obtain solid waste-based foam concrete.

[0013] Preferably, the solid waste powder includes at least one of steel slag powder, slag powder, and bottom ash;

[0014] In the step of adding water, solid waste powder, and cement into the stirring device, the mass ratio of water, solid waste powder, and cement is (40 - 60):(0 - 100):(0 - 100);

[0015] The ratio of the mass of water to the sum of the masses of solid waste powder and cement is (40 - 60):100.

[0016] Preferably, the foaming agent includes surfactant-based foaming agents, protein-based foaming agents, composite foaming agents, and chemical foaming agents;

[0017] The surfactant-based foaming agents include at least one of rosin resin-based surfactants and synthetic surfactants;

[0018] The protein-based foaming agents include at least one of animal protein foaming agents and plant protein foaming agents;

[0019] The composite foaming agents include protein and surfactant composite foaming agents;

[0020] The chemical foaming agents include aluminum powder;

[0021] In the step of mixing the foaming agent with water to obtain a foaming liquid, the mass ratio of the foaming agent to water is 1:(40 - 100);

[0022] After the carbonization stirring is completed, relieve the pressure to discharge the CO2 in the stirring device, and then add the foam into the stirring device. The mass of the added foam is 0.5 - 2% of the sum of the masses of the solid waste powder and cement.

[0023] Preferably, the solid waste powder and cement are added to a stirring device and stirred for 1 - 3 minutes, then water is added and stirring is continued for 1 - 3 minutes to complete pre-stirring;

[0024] After pre-stirring is completed, the stirring device is evacuated, and then CO2 is introduced into the stirring device so that the CO2 pressure in the stirring device is 0.01 MPa - 0.5 MPa. Then, it is stirred at 100 - 120 r / min for 0.5 - 2 minutes, and then stirred at 40 - 80 r / min for 0.5 - 2 minutes to complete carbonation stirring;

[0025] After carbonation stirring is completed, the pressure is released to discharge the CO2 in the stirring device, and then foam is added to the stirring device. It is stirred at 40 - 80 r / min for 0.5 - 1 minute, and then stirred at 90 - 120 r / min for 10 s - 15 s, 40 r / min - 80 r / min for 10 s - 15 s, 90 - 120 r / min for 10 s - 15 s, and finally stirred at 40 - 80 r / min for 0.5 - 1 minute.

[0026] Preferably, the total mass fraction of SiO2, Al2O3, and CaO in the solid waste powder is ≥60%;

[0027] The mesh number of the solid waste powder is ≥200 meshes;

[0028] After carbonation stirring is completed, the pressure is released to discharge the CO2 in the stirring device and it is introduced into a CO2 adsorbent to absorb and reuse the remaining unreacted CO2.

[0029] Preferably, after obtaining the solid waste-based foam concrete, it further includes pouring the solid waste-based foam concrete into a mold, covering it with a plastic wrap, and curing it indoors for 2 - 3 days, demolding, and then placing the demolded sample in a standard curing room for curing for 25 - 30 days.

[0030] Preferably, the stirring device includes:

[0031] A tank body, which is provided with a stirring mechanism inside;

[0032] A cover plate, which is provided with a CO2 inlet pipe and a vacuum extraction pipe; the CO2 inlet pipe is connected to a CO2 gas cylinder and is used to introduce CO2 into the tank body; the cover plate is screwed onto the tank body, and a sealing ring is provided at the connection between the cover plate and the tank body;

[0033] A lifting mechanism, which is used to lift the cover plate to cover the cover plate on the tank body or remove the cover plate from the tank body;

[0034] The method for preparing the solid waste-based foam concrete includes the following steps:

[0035] Add water, solid waste powder, and cement into the tank body. After covering the cover plate on the tank body, start the stirring mechanism for pre-stirring;

[0036] After the pre-stirring is completed, evacuate the tank body, and introduce CO2 into the tank body using a CO2 gas cylinder for carbonization stirring;

[0037] Mix the foaming agent with water to obtain a foaming liquid;

[0038] Add the foaming liquid into a foaming machine for foaming to obtain foam;

[0039] After the carbonization stirring is completed, relieve the pressure to discharge the CO2 in the tank body, then add the foam into the tank body and stir again to obtain solid waste-based foam concrete.

[0040] Preferably, the stirring mechanism includes:

[0041] A stirring motor, located on the cover plate;

[0042] A speed reducer, located on the cover plate, and the rotating shaft of the stirring motor is connected to the speed reducer;

[0043] A stirring shaft, located in the tank body;

[0044] A mechanical seal rotating shaft, its upper end is connected to the rotating shaft of the speed reducer, and its lower end passes through the cover plate and is connected to the stirring shaft;

[0045] Stirring paddles, located in the tank body, and the stirring paddles are connected to the stirring shaft.

[0046] Preferably, the lifting mechanism includes:

[0047] A bracket;

[0048] A first lifting member, which is provided on the cover plate;

[0049] A second lifting member, which is provided on the bracket;

[0050] A cable, one end of which is connected to the first lifting member and the other end passes through the second lifting member and is connected to a driving member;

[0051] Wherein, the driving member is used to drive the cover plate to move up and down in the vertical direction.

[0052] Preferably, a pressure gauge is provided on the cover plate;

[0053] A safety pressure relief pipe is provided on the cover plate, and a pressure relief valve is provided on the safety pressure relief pipe;

[0054] A transparent observation window is also provided on the cover plate;

[0055] An intake valve is provided on the CO2 inlet pipe;

[0056] An exhaust valve is provided on the evacuation pipe.

[0057] The preparation method of the solid waste-based foamed concrete of the present invention has the following beneficial effects compared with the prior art:

[0058] 1. In the preparation method of the solid waste-based foamed concrete of the present invention, the solid waste-based foamed concrete is prepared by synchronous carbonization stirring under variable air pressure conditions. It is not limited to pre-carbonized fresh concrete, and the method can be used to pre-carbonize solid waste raw materials, so as to realize the upgrading and optimization of the performance of solid waste raw materials and make them better serve in concrete. At the same time, through the present invention, the problem of material mechanical property defects caused by the traditional uneven internal carbonization gradient can be effectively avoided. In addition, the solid waste-based foamed concrete combines environmental protection, functionality and economy, and is a model of green building materials that "turns waste into treasure". It is especially suitable for engineering projects with high requirements for light weight, heat preservation and solid waste disposal, and has broad prospects for future development. The combination of solid waste and pre-carbonization technology provides an efficient and low-carbon solution for solid waste management through resource utilization, reduction and harmless treatment;

[0059] 2. By introducing a synchronous carbonization stirring device under variable air pressure conditions designed in the present invention, the convenience of feeding, discharging and tank cleaning is realized, and the solid waste-based foamed concrete is prepared by synchronous carbonization stirring under variable air pressure conditions; this method of preparing the solid waste-based foamed concrete by synchronous carbonization stirring under variable air pressure conditions can better control the carbonization process and achieve a more uniform carbonization effect; compared with traditional carbonization curing, it can solve the problem of material mechanical property defects caused by uneven internal carbonization gradient. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0061] Figure 1 It is a schematic structural diagram of the preparation method of the solid waste-based foamed concrete of the present invention;

[0062] Figure 2 It is a schematic structural diagram of another view of the preparation method of the solid waste-based foamed concrete of the present invention;

[0063] Figure 3 It is a schematic structural diagram of the cover plate of the present invention;

[0064] Figure 4 It is a schematic structural diagram of the stirring paddle of the present invention;

[0065] Figure 5 Structural schematic diagram of the tank body of the present invention;

[0066] Figure 6 Structural schematic diagram of another view of the tank body of the present invention;

[0067] Figure 7 Structural schematic diagram of the base and bracket of the present invention;

[0068] Figure 8 Structural schematic diagram of the positioning block arranged on the base of the present invention;

[0069] Figure 9 Test results of the compressive strength and dry density of waste-based foam concrete with different steel slag dosages in Examples 1 to 6;

[0070] Figure 10 Test results of the compressive strength and dry density of waste-based foam concrete with different water-binder ratios in Examples 7 to 9. Detailed implementation manners

[0071] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations.

[0072] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0073] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0074] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper" etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship when the product of the invention is normally placed, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0075] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0076] It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". The various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the counted range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0077] The embodiment of the present application provides a preparation method of solid waste-based foam concrete, including the following steps:

[0078] S1. Provide a stirring device;

[0079] S2. Add water, solid waste powder, and cement into the stirring device for pre-stirring;

[0080] S3. After the pre-stirring is completed, evacuate the stirring device, and then introduce CO2 into the stirring device for carbonization stirring;

[0081] S4. Mix the foaming agent with water to obtain a foaming liquid;

[0082] S5. Add the foaming liquid into a foaming machine for foaming to obtain foam;

[0083] S6. After the carbonization stirring is completed, release the pressure to discharge the CO2 in the stirring device, and then add the foam into the stirring device and stir again to obtain solid waste-based foam concrete.

[0084] The preparation method of solid waste-based foamed concrete of the present invention comprises the following steps: adding raw materials such as water, solid waste powder, cement, etc. into a stirring device for pre-stirring until uniform, then closing the stirring device and evacuating, then injecting CO2 into the reactor to a predetermined pressure, and then performing synchronous carbonization stirring according to a predetermined stirring program; during the synchronous carbonization stirring, firstly mixing a foaming agent and water uniformly to obtain a foaming liquid, and then using a foaming machine to prepare a required amount of foam; after the synchronous carbonization stirring is completed, releasing the pressure and exhausting the air (the remaining CO2 can be absorbed and reused by a CO2 adsorbent), and adding the prepared foam thereto, and then stirring until uniform according to the predetermined stirring program to obtain solid waste-based foamed concrete.

[0085] In traditional carbonization curing, the diffusion of CO2 in the hardened cement-based material is limited, resulting in uneven distribution of carbonization products from the outside to the inside, which ultimately leads to the defect of uneven mechanical properties of the material. However, the present invention implements carbonization during the mixing process of the fresh slurry. Compared with the traditional carbonization curing of the test block after hardening, the present invention can obviously make the slurry carbonized more uniformly.

[0086] In some embodiments, the solid waste powder includes but is not limited to at least one of steel slag powder, slag powder, and bottom ash.

[0087] In some embodiments, in the step of adding water, solid waste powder, and cement to a stirring device, the mass ratio of water, solid waste powder, and cement is (40-60):(0-100):(0-100);

[0088] The ratio of the mass of water to the sum of the mass of solid waste powder and cement is (40-60):100.

[0089] Solid waste powder and cement are called cementitious materials.

[0090] In some embodiments, the foaming agent includes a surfactant foaming agent, a protein foaming agent, a composite foaming agent, and a chemical foaming agent;

[0091] The surfactant foaming agent includes at least one of a rosin resin surfactant and a synthetic surfactant;

[0092] The protein foaming agent includes at least one of an animal protein foaming agent and a plant protein foaming agent;

[0093] Composite foaming agents include protein and surfactant composite foaming agents;

[0094] Chemical foaming agents include aluminum powder;

[0095] In the step of mixing a foaming agent with water to obtain a foaming solution, the mass ratio of the foaming agent to water is 1:(40-100);

[0096] After the carbonization stirring is completed, the pressure is released to discharge CO₂ in the stirring device, and then foam is added to the stirring device. The mass of the added foam is 0.5-2% of the sum of the masses of the solid waste powder and cement.

[0097] Specifically, in some embodiments, the foaming liquid is added to a foaming machine for foaming to obtain foam; in the foaming machine, the foaming liquid is mixed with gas through a pressurizing system (such as a high-pressure pump or an air compressor) to form uniform and delicate foam.

[0098] In some embodiments, the solid waste powder and cement are added to the stirring device and stirred for 1-3 minutes, then water is added, and stirring is continued for 1-3 minutes to complete pre-stirring;

[0099] After the pre-stirring is completed, the stirring device is evacuated, and then CO₂ is introduced into the stirring device to make the CO₂ pressure in the stirring device 0.01 MPa - 0.5 MPa, and then stirred at 100-120 r / min for 0.5-2 minutes, and then stirred at 40-80 r / min for 0.5-2 minutes to complete carbonization stirring;

[0100] In some embodiments, it should be noted that: during the carbonization stirring of concrete, especially in a cylindrical stirring device, as the stirring speed increases, the slurry adheres to the wall surface under the action of centrifugal force, resulting in the gradual accumulation of the slurry on the surface of the cylinder wall. This phenomenon not only affects the homogeneity of the mixture, but also has an adverse effect on the diffusion and reaction kinetics of CO₂. In view of the above problems, the present invention proposes a variable-speed cyclic stirring strategy, and by alternately switching between high and low speeds, the wall adhesion effect of the slurry is effectively reduced. This stirring method not only optimizes the homogeneity of the fresh slurry, but also improves the diffusion efficiency of CO₂ in the slurry, thereby achieving more uniform carbonization.

[0101] After the carbonization stirring is completed, the pressure is released to discharge CO₂ in the stirring device, and then foam is added to the stirring device. Stir at 40-80 r / min for 0.5-1 minute, then stir at 90-120 r / min for 10 s-15 s, 40 r / min-80 r / min for 10 s-15 s, 90-120 r / min for 10 s-15 s, and finally stir at 40-80 r / min for 0.5-1 minute. The purpose of this variable-speed cyclic stirring strategy is to make the foam and the fresh slurry mix evenly and ensure the homogeneity of the solid waste-based foam concrete.

[0102] In some embodiments, the total mass fraction of SiO₂, Al₂O₃, and CaO in the solid waste powder ≥ 60%;

[0103] The mesh number of the solid waste powder ≥ 200 meshes;

[0104] After the carbonization stirring is completed, the pressure is released to discharge CO2 in the stirring device and introduce it into the CO2 adsorbent to absorb and reuse the remaining unreacted CO2.

[0105] In some embodiments, after obtaining the solid waste-based foamed concrete, it further includes pouring the solid waste-based foamed concrete into a mold, covering it with a plastic film, and curing it indoors for 2 to 3 days, demolding, and then placing the demolded sample in a standard curing room for 25 to 30 days.

[0106] The process parameters controlled during indoor curing are: the temperature is controlled at (20 ± 5) °C, and the relative humidity is maintained at 50 to 70%.

[0107] The process parameters controlled during standard curing are: the temperature is controlled at (20 ± 2) °C, and the relative humidity is not less than 95%.

[0108] In some embodiments, as Figures 1 to 8 shown, the stirring device includes:

[0109] A tank body 1, inside which there is a stirring mechanism;

[0110] A cover plate 2, on which there is a CO2 inlet pipe 21 and a vacuum extraction pipe 22; the CO2 inlet pipe 21 is connected to a CO2 gas cylinder for introducing CO2 into the tank body 1; the cover plate 2 is screwed to the tank body 1, and a sealing ring 3 is provided at the connection between the cover plate 2 and the tank body 1;

[0111] A lifting mechanism for lifting the cover plate 2 to cover the cover plate 2 on the tank body 1 or removing the cover plate 2 from the tank body 1.

[0112] The stirring device used in the preparation method of the solid waste-based foamed concrete of the present invention includes a tank body 1 and a cover plate 2. The upper end of the tank body 1 is open, and the cover plate 2 is arranged on the upper end opening of the tank body 1. The cover plate 2 is screwed to the tank body 1, and a sealing ring 3 is provided at the connection between the cover plate 2 and the tank body 1. A sealed space is formed between the cover plate 2 and the tank body 1; at the same time, the cover plate 2 is also provided with a CO2 inlet pipe 21 and a vacuum extraction pipe 22. The CO2 inlet pipe 21 is connected to a CO2 gas cylinder, and CO2 gas with a certain pressure is provided by the CO2 gas cylinder. The CO2 gas enters the tank body 1 through the CO2 inlet pipe 21; at the same time, before use, the vacuum extraction pipe 22 is connected to a vacuum pump, and the air in the tank body 1 is evacuated by the vacuum pump to form a vacuum environment; further, it also includes a lifting mechanism for lifting the cover plate 2 to cover the cover plate 2 on the tank body 1 or removing the cover plate 2 from the tank body 1;

[0113] The preparation method of the solid waste-based foamed concrete of the present invention is as follows: First, use the lifting mechanism to raise the cover plate 2 so that the cover plate 2 is separated from the tank body 1. Then, add the raw materials for preparing the solid waste-based foamed concrete (water, solid waste powder, cement) into the tank body 1. Then, use the lifting mechanism to lower the cover plate 2 so that the cover plate 2 covers the tank body 1 and is screwed and sealed. Start the stirring mechanism for pre-stirring; after the pre-stirring is completed, start the vacuum pump to evacuate the tank body 1, and then introduce CO2 gas with a preset pressure into the tank body 1 through the CO2 inlet pipe 21 for carbonization stirring; after the carbonization stirring is completed, relieve the pressure to discharge the CO2 gas in the tank body 1 (the CO2 can be introduced into the CO2 adsorbent to absorb and reuse the remaining unreacted CO2). After carbonization, use the lifting mechanism to raise the cover plate 2 so that the cover plate 2 is separated from the tank body 1. Then, add foam into the tank body 1. Then, use the lifting mechanism to lower the cover plate 2 so that the cover plate 2 covers the tank body 1 and is screwed and sealed, and continue stirring to obtain the solid waste-based foamed concrete. Once again, use the lifting mechanism to raise the cover plate 2 so that the cover plate 2 is separated from the tank body 1, take out the solid waste-based foamed concrete, and clean the tank body 1; The preparation method of the solid waste-based foamed concrete of the present invention uses the detachable and separable design of the tank body 1 and the cover plate 2 and combines the lifting mechanism. Compared with the conventional integral molding design of the tank body 1 and the cover plate 2, it is not only convenient for feeding and taking materials, but also convenient for cleaning the inside of the tank body 1.

[0114] In some embodiments, an annular plate 11 is sleeved on the outer periphery of the port of the tank body 1;

[0115] Corresponding screw holes 10 are provided on the cover plate 2 and the annular plate 11. A screw connection member is screwed into the screw holes 10 to cover the cover plate 2 on the port of the tank body 1. A sealing ring 3 is provided at the connection between the cover plate 2 and the port of the tank body 1.

[0116] In the above embodiments, an annular plate 11 is sleeved on the outer periphery of the port of the tank body 1, that is, an annular plate 11 is sleeved at the upper opening of the tank body 1. Corresponding screw holes 10 are provided on the cover plate 2 and the annular plate 11. By screwing a screw into the screw holes 10, the cover plate 2 and the tank body 1 are screwed together. A sealing ring 3 is provided at the connection between the cover plate 2 and the port of the tank body 1; specifically, a sealing ring can be provided on the inner wall of the port of the tank body 1 to increase the sealing performance.

[0117] In some embodiments, a rotatable rotating member 12 is provided on the annular plate 11, and the upper end surface of the rotating member 12 is an inclined surface 13 that slopes downward;

[0118] A fastener 23 is provided on the cover plate 2, and a gap 27 is formed between the fastener 23 and the surface of the cover plate 2;

[0119] Among them, when the cover plate 2 covers the tank body 1, the rotating member 12 rotates, and the inclined surface 13 of the rotating member 12 is clamped in the gap 27.

[0120] In the above embodiment, a rotating shaft is provided on the annular plate 11, and the rotating member 12 can rotate around the rotating shaft; a fastener 23 is provided on the cover plate 2. The fastener 23 is L-shaped and includes a horizontal portion and a vertical portion. The vertical portion is located on the cover plate 2, the horizontal portion is connected to the vertical portion, and a gap 27 is formed between the horizontal portion and the surface of the cover plate 2; before use, first rotate the rotating member 12 to avoid interference of the rotating member 12 with the cover plate 2, so as to facilitate covering the cover plate 2 on the tank body 1. At this time, the cover plate 2 and the screw holes 10 on the annular plate 11 are in the same position, and then rotate the rotating member 12 again so that the inclined surface 13 is clamped in the gap 27, so that the cover plate 2 and the tank body 1 are clamped. Finally, use screws to be screwed into the screw holes 10 to screw and fix the cover plate 2 and the tank body 1; the clamping connection method between the cover plate 2 and the tank body 1 combined with the screwing connection between the cover plate 2 and the tank body 1 effectively improves the sealing efficiency.

[0121] In some embodiments, the lifting mechanism includes:

[0122] A bracket 4;

[0123] A first lifting member 41, which is provided on the cover plate 2;

[0124] A second lifting member 42, which is provided on the bracket 4;

[0125] A cable 43, one end of which is connected to the first lifting member 41 and the other end passes through the second lifting member 42 and then is connected to the driving member 44;

[0126] The driving member 44 is used to drive the cover plate 2 to move up and down in the vertical direction.

[0127] In the above embodiment, the lifting mechanism includes: a bracket 4, a first lifting member 41, a second lifting member 42, a cable 43, and a driving member 44; a first lifting member 41 is provided on the cover plate 2, a second lifting member 42 is provided on the bracket 4, and the cable 43. One end of the cable 43 is fixed to the first lifting member 41, and the other end passes through the second lifting member 42 and then is connected to the driving member 44; in practice, a pulley can also be provided on the bracket 4, and the cable 43 passes through the second lifting member 42 and then bypasses the pulley and is connected to the driving member 44; the driving member drives the cover plate 2 to move up and down in the vertical direction, so that the cover plate 2 is lifted and lowered to cover the cover plate 2 on the tank body 1 or take the cover plate 2 out of the tank body 1; the driving member 44 is an existing driving member fixed on the base, such as an existing driving member including a telescopic cylinder, a telescopic rod, etc. The driving member 44 moves up and down to drive the cover plate 2 to move up and down in the vertical direction; the driving member 44 can also adopt a motor, and the motor rotates to make the cable 43 and then drive the cover plate to move; a controller 45 is also included, which is used to control the up and down telescopic movement of existing driving members such as telescopic cylinders and telescopic rods.

[0128] In some embodiments, the stirring mechanism includes:

[0129] The stirring motor 5 is located on the cover plate 2;

[0130] The stirring shaft 51 is located inside the tank body 1, and its upper end passes through the cover plate 2 and is connected to the rotating shaft of the stirring motor 5;

[0131] The stirring paddle 52 is located inside the tank body 1, and the stirring paddle 52 is connected to the stirring shaft 51.

[0132] In some embodiments, it further includes:

[0133] The speed reducer 53 is located on the cover plate 2, and the rotating shaft of the stirring motor 5 is connected to the speed reducer 53;

[0134] The mechanical seal rotating shaft 54, its upper end is connected to the rotating shaft of the speed reducer 53, and its lower end passes through the cover plate 2 and is connected to the stirring shaft 51;

[0135] The rotation of the stirring motor 5 drives the speed reducer 53 to make the stirring shaft 51 rotate;

[0136] The stirring paddle 52 is snap-connected to the stirring shaft 51.

[0137] In the above embodiments, the stirring paddle 52 is snap-connected to the stirring shaft 51. For example, it can be a snap-fastening connection. Through the snap-fastening quick connection, it is convenient for the replacement, disassembly and assembly of different types of stirring paddles; further, as Figure 4 shown, the upper end of the stirring paddle 52 is snap-connected to the stirring shaft 51; the stirring paddle 52 has different forms, such as anchor type, frame type, etc.; through the combination of the speed reducer and the stirring motor, the efficient transmission of torsional power and the fine control of the rotational speed are realized; the upper end of the stirring shaft 51 passes through the cover plate 2 through the mechanical seal rotating shaft 54 and is connected to the rotating shaft of the speed reducer 53, and stirring can be realized under vacuum or different CO2 gas pressures during the stirring process; the mechanical seal rotating shaft 54 is sealed with the cover plate 2.

[0138] In some embodiments, a pressure gauge 26 is provided on the cover plate 2 for monitoring the air pressure inside the tank body 1;

[0139] A safety relief pipe 24 is provided on the cover plate 2, and a relief valve is provided on the safety relief pipe 24 for preventing the pressure in the tank from exceeding the maximum allowable pressure; when the pressure in the tank body 1 reaches or exceeds the set pressure, the relief valve will automatically open to release the excess pressure, thereby protecting the tank body 1.

[0140] In some embodiments, it further includes a base 6;

[0141] The bracket 4 is located on the base 6;

[0142] Two positioning blocks 61 are provided on the base 6, a positioning groove 62 is formed between the two positioning blocks 61, and a positioning protrusion 14 is provided at the lower end of the tank body 1 corresponding to the positioning groove, and the positioning protrusion 14 is located in the positioning groove 62.

[0143] In some embodiments, there are also tank support plates 63 provided on both sides of the tank body 1 of the base 6;

[0144] A rotating rod 64 is rotatably provided on the tank support plate 63. One end of the rotating rod 64 away from the tank support plate 63 is connected to the tank body, and the rotation of the rotating rod 64 drives the rotation of the tank body 1;

[0145] A bolt 65 sequentially passes through the positioning block 61 and the positioning protrusion 14 to fix the tank body 1.

[0146] In the above embodiment, the tank support plates 63 are vertically provided on both sides of the tank body 1 on the base 6, the rotating rod 64 is horizontally arranged, one end of the rotating rod 64 is connected to the tank body 1, and the other end can rotate relative to the tank support plate 63; during the carbonization process, the positioning protrusion 14 is located in the positioning groove 62, and at the same time, the bolt 65 sequentially passes through the positioning block 61 and the positioning protrusion 14 to fix the tank body 1, so that the tank body 1 will not shake during the stirring process; after the carbonization is completed, after the screwed part is screwed out of the screw hole 10, the cover plate 2 is lifted by the lifting mechanism to separate the cover plate 2 from the tank body 1, and then after the bolt 65 is taken out, the tank body 1 is rotated to pour out the carbonized product.

[0147] In some embodiments, the cover plate 2 is also provided with a transparent observation window 25, and the transparent observation window 25 is used to observe the reaction condition inside the tank body 1;

[0148] An intake valve is provided on the CO2 intake pipe 21. By opening the intake valve, it is convenient to introduce CO2 into the tank body 1;

[0149] An exhaust valve is provided on the vacuum extraction pipe 22. By opening the exhaust valve, it is convenient to extract vacuum or discharge the gas inside the tank body 1.

[0150] Specifically, the working process of preparing solid waste-based foamed concrete using the stirring device of the present invention is as follows: First, use the lifting mechanism to raise the cover plate 2 so that the cover plate 2 is separated from the tank body 1. Then, add the raw materials for preparing solid waste-based foamed concrete (water, solid waste powder, cement) into the tank body 1. Then, use the lifting mechanism to lower the cover plate 2 so that the cover plate 2 covers the tank body 1. At this time, the screw holes 10 on the cover plate 2 and the annular plate 11 are aligned. Then, rotate the rotating member 12 so that the inclined surface 13 of the rotating member 12 is clamped in the gap 27 between the fastener 23 and the surface of the cover plate 2. Then, screw the screw member into the screw hole 10, so that the cover plate 2 and the tank body 1 are sealed. Start the stirring motor 5, and the rotation of the stirring motor 5 drives the reduction gear 53 to make the stirring paddle 52 rotate to pre-stir the raw materials. During the pre-stirring process, the internal stirring situation can be observed through the transparent observation window 25. After the pre-stirring is completed, start the vacuum pump to evacuate the tank body 1, and then use the CO2 inlet pipe 21 to introduce CO2 gas with a preset pressure into the tank body 1. Start the stirring motor 5 again for carbonization stirring. After the carbonization stirring is completed, discharge the CO2 gas in the tank body 1 through the vacuum extraction pipe 22, then rotate the rotating member 12 to move it out of the gap 27, then rotate and remove the screw member, and then raise the cover plate 2 through the lifting mechanism so that the cover plate 2 is separated from the tank body 1. Then, add foam into the tank body 1, and then use the lifting mechanism to lower the cover plate 2 so that the cover plate 2 covers the tank body 1 and is screwed and sealed. Continue to start the stirring motor 5 for stirring to obtain solid waste-based foamed concrete. Again, use the lifting mechanism to raise the cover plate 2 so that the cover plate 2 is separated from the tank body 1, rotate the tank body 1, and take out the solid waste-based foamed concrete. Subsequently, the cover plate 2, the tank body 1, the stirring paddle 52, etc. should be cleaned immediately to prepare the next batch of solid waste-based foamed concrete and avoid contaminating the stirring materials for the next batch.

[0151] The preparation method of the solid waste-based foamed concrete of the present invention prepares the solid waste-based foamed concrete by synchronous carbonization stirring under variable air pressure conditions, which is not limited to pre-carbonizing fresh concrete, but can also use its method to pre-carbonize solid waste raw materials, so as to realize the upgrading and optimization of the performance of solid waste raw materials and make them better serve concrete. At the same time, through the present invention, the problem of material mechanical property defects that may be caused by the traditional uneven internal carbonization gradient can be effectively avoided. In addition, the solid waste-based foamed concrete has the characteristics of environmental protection, functionality and economy, and is a model of "turning waste into treasure" green building materials, especially suitable for engineering projects with high requirements for light weight, heat preservation and solid waste disposal. It has broad prospects for future development. The combination of solid waste and pre-carbonization technology provides an efficient and low-carbon solution for solid waste management through resource utilization, reduction and harmless treatment.

[0152] Compared with the preparation method of ordinary solid waste-based foamed concrete, the present invention has the following advantages:

[0153] (1) By introducing a synchronous carbonization stirring device under variable air pressure conditions designed, the convenience of feeding, discharging, and tank cleaning is achieved, as well as the synchronous carbonization stirring preparation of solid waste-based foam concrete under variable air pressure conditions;

[0154] (2) This method for preparing solid waste-based foam concrete by synchronous carbonization stirring under variable air pressure conditions can better control the carbonization process and achieve a more uniform carbonization effect;

[0155] (3) Compared with traditional carbonization curing, it can solve the problem of material mechanical property defects that may be caused by uneven internal carbonization gradients.

[0156] Generally speaking, the method for preparing solid waste-based foam concrete by synchronous carbonization stirring under variable air pressure conditions of the present invention not only provides a new solution for the optimization treatment of the material properties of solid waste, but also has important practical significance in building energy conservation and emission reduction to achieve "treating waste with waste".

[0157] The following further illustrates the preparation method of the solid waste-based foam concrete of the present application with specific examples. This part further illustrates the content of the present invention in combination with specific examples, but should not be construed as a limitation to the present invention. Unless otherwise specified, the technical means adopted in the examples are conventional means well-known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment adopted in the present invention are conventional reagents, methods, and equipment in the art.

[0158] In the following examples, steel slag powder and reference cement (specifically P·I 42.5 Portland cement) are used as the main cementitious materials for foam concrete. The fineness of the steel slag powder is 325 mesh (D 50 = 13.16 μm); the steel slag powder includes the following components by mass fraction: calcium oxide 46.7%, magnesium oxide 5.51%, silicon dioxide 14.1%, aluminum oxide 3.02%, iron oxide (i.e., ferric oxide) 21.3%, manganese oxide 3.58%, phosphorus oxide (i.e., phosphorus pentoxide) 2.74%, titanium dioxide 1.24%, and other unavoidable impurities 1.81%;

[0159] In the following examples, animal protein foaming agent is used as the foaming agent in the examples of the present invention, and the mass ratio of water to the foaming agent is 1:40. Specifically, the animal protein foaming agent model is FP-50, CAS: 25155-30-0, purchased from Liaocheng Zhihui Building Materials Co., Ltd.

[0160] Example 1

[0161] This example provides a method for preparing solid waste-based foam concrete, including the following steps:

[0162] S1. Provide Figures 1 to 8 the stirring device shown;

[0163] S2. First, place 100 parts by weight of cement and 0 parts by weight of steel slag powder in the tank and dry mix for 1 min. Then, add 50 parts by weight of water to the tank and mix and stir for 1 min to complete the pre-stirring.

[0164] S3. After the pre-stirring is completed, evacuate the tank, then introduce CO2 into the stirring device until the pressure in the tank is 0.1 Mpa, stir at 120 r / min for 1 min, and then stir at 60 r / min for 1 min (this process is carbonation stirring) to prevent the occurrence of slurry wall sticking caused by the reduction of the workability of the fresh paste due to the hydration reaction and carbonation reaction, and complete the carbonation stirring.

[0165] S4. Mix the animal protein foaming agent and water to obtain a foaming liquid; the mass ratio of the animal protein foaming agent to water is 1:40.

[0166] S5. Add the foaming liquid to a foaming machine for foaming to obtain foam.

[0167] S6. After the carbonation stirring is completed, relieve the pressure to discharge the CO2 in the tank (the remaining CO2 can be introduced into the CO2 adsorbent for recycling), then add foam to the tank (the added foam mass is 1.8% of the sum of the masses of cement and steel slag powder), stir at 60 r / min for 30 s, then stir at 120 r / min for 10 s, 60 r / min for 10 s, and 120 r / min for 10 s to make the foam and the pre-carbonated fresh paste fully mixed and uniform, and finally stir at 60 r / min for 1 min to obtain solid waste-based foam concrete (denoted as S0).

[0168] Example 2

[0169] The preparation method of the solid waste-based foam concrete provided in this example is the same as that in Example 1, except that in step S2: first, place 80 parts by weight of cement and 20 parts by weight of steel slag powder in the tank and dry mix for 1 min, then add 50 parts by weight of water to the tank and mix and stir for 1 min to complete the pre-stirring, and the remaining steps are the same as those in Example 1. The prepared solid waste-based foam concrete is denoted as S20.

[0170] Example 3

[0171] The preparation method of the solid waste-based foam concrete provided in this example is the same as that in Example 1, except that in step S2: first, place 60 parts by weight of cement and 40 parts by weight of steel slag powder in the tank and dry mix for 1 min, then add 50 parts by weight of water to the tank and mix and stir for 1 min to complete the pre-stirring, and the remaining steps are the same as those in Example 1. The prepared solid waste-based foam concrete is denoted as S40.

[0172] Example 4

[0173] The preparation method of the solid waste-based foamed concrete provided in this embodiment is the same as that in Embodiment 1, except that in step S2: first, 40 parts by weight of cement and 60 parts by weight of steel slag powder are placed in the tank and dry-mixed for 1 min, then 50 parts by weight of water is added to the tank, and they are mixed and stirred for 1 min to complete the pre-stirring. The remaining steps are the same as those in Embodiment 1. The prepared solid waste-based foamed concrete is denoted as S60.

[0174] Embodiment 5

[0175] The preparation method of the solid waste-based foamed concrete provided in this embodiment is the same as that in Embodiment 1, except that in step S2: first, 20 parts by weight of cement and 80 parts by weight of steel slag powder are placed in the tank and dry-mixed for 1 min, then 50 parts by weight of water is added to the tank, and they are mixed and stirred for 1 min to complete the pre-stirring. The remaining steps are the same as those in Embodiment 1. The prepared solid waste-based foamed concrete is denoted as S80.

[0176] Embodiment 6

[0177] The preparation method of the solid waste-based foamed concrete provided in this embodiment is the same as that in Embodiment 1, except that in step S2: first, 0 parts by weight of cement and 100 parts by weight of steel slag powder are placed in the tank and dry-mixed for 1 min, then 50 parts by weight of water is added to the tank, and they are mixed and stirred for 1 min to complete the pre-stirring. The remaining steps are the same as those in Embodiment 1. The prepared solid waste-based foamed concrete is denoted as S100.

[0178] Embodiment 7

[0179] The preparation method of the solid waste-based foamed concrete provided in this embodiment is the same as that in Embodiment 1, except that in step S2: first, 60 parts by weight of cement and 40 parts by weight of steel slag powder are placed in the tank and dry-mixed for 1 min, then 40 parts by weight of water is added to the tank, and they are mixed and stirred for 1 min to complete the pre-stirring. The remaining steps are the same as those in Embodiment 1. The prepared solid waste-based foamed concrete is denoted as W / B-0.4.

[0180] Embodiment 8

[0181] The preparation method of the solid waste-based foamed concrete provided in this embodiment is the same as that in Embodiment 1, except that in step S2: first, 60 parts by weight of cement and 40 parts by weight of steel slag powder are placed in the tank and dry-mixed for 1 min, then 50 parts by weight of water is added to the tank, and they are mixed and stirred for 1 min to complete the pre-stirring. The remaining steps are the same as those in Embodiment 1. The prepared solid waste-based foamed concrete is denoted as W / B-0.5. (The process parameters of Embodiment 8 are the same as those of Embodiment 3).

[0182] Embodiment 9

[0183] The preparation method of the solid waste-based foam concrete provided in this embodiment is the same as that in Embodiment 1, except that in step S2: first, 60 parts by weight of cement and 40 parts by weight of steel slag powder are placed in a tank and dry-mixed for 1 min, then 60 parts by weight of water are added to the tank and mixed and stirred for 1 min to complete pre-stirring. The remaining steps are the same as those in Embodiment 1. The prepared solid waste-based foam concrete is denoted as W / B-0.6.

[0184] According to the methods in the above Embodiments 1 to 6, solid waste-based foam concretes S0, S20, S40, S60, S80, and S100 are respectively prepared. The obtained foam concretes S0, S20, S40, S60, S80, and S100 are poured into a 100 mm×100 mm×100 mm triple cube mold, covered with plastic wrap and placed indoors for curing for 2 days (the curing parameters are: temperature 20 °C, relative humidity maintained at 60%). After demolding, the demolded samples are placed in a standard curing room for curing until 28 days (the process parameters controlled by the standard curing are: temperature 20 °C, relative humidity 98%). According to "Foamed Concrete" JG / T 266-2011, its 28-day compressive strength and dry density are tested. The test results are shown in Figure 9 .

[0185] It can be seen from Figure 9 that as the steel slag replacement amount increases, the compressive strength significantly decreases from 8.50 MPa to 2.24 MPa, while the dry density continuously rises from 1238.39 kg / m 3 to 1528.04 kg / m 3 . The decrease in compressive strength may be attributed to: the cementitious activity of steel slag is lower than that of cement, and the C-S-H gel generated by the hydration reaction after replacement decreases, resulting in a reduction in the strength of the matrix structure. Although the synchronous carbonization process can partially compensate for the strength by generating calcium carbonate (CaCO3) through CO2 injection, the active components of steel slag are insufficient at high replacement amounts, and the carbonization contribution is limited. In addition, the increase in the viscosity of the slurry at high replacement amounts may affect the foaming uniformity, resulting in uneven bubble distribution and further weakening the mechanical properties. The increase in dry density may be attributed to: the density of steel slag particles (3.2 - 3.6 g / cm 3 ) is higher than that of cement (about 3.1 g / cm 3 ), and the overall compactness of the material increases after replacement. At the same time, the decrease in the fluidity of the slurry at high replacement amounts may inhibit the foaming effect, the porosity decreases, and the densification trend intensifies. Nevertheless, for low steel slag replacement amounts (0% - 40%): the dry density is 1238.39 - 1297.94 kg / m 3, the compressive strength is 5.47 MPa to 8.50 MPa. Corresponding to the specification "Foamed Concrete" JG / T 266-2011, the density grade is A12 (4.5 - 6 MPa), and its strength is significantly higher than the conventional requirements. For medium to high steel slag replacement ratios (60% - 100%), although the strength is insufficient, it can still be cast and formed under such high admixture ratios, which is a potential improvement point. Subsequently, the performance can be improved by composite material design or optimized carbonization process. In summary, based on the steel slag-based foamed concrete prepared by the present invention, under similar density conditions, the compressive strength of low to medium steel slag replacement ratios (≤60%) is significantly better than the existing specification standards (such as JG / T 266-2011), especially outstanding in the lightweight field (A12 - A14 grades); while the high replacement ratio (≥80%) can meet the basic strength requirements, but further optimization is needed to match the higher density grade (A16) standard. This technology has significant competitiveness in the medium and low replacement ratio range, providing an innovative path for the development of green building materials.

[0186] According to the methods of Examples 7 - 9 above, the waste solid-based foamed concretes with a steel slag replacement ratio of 40% and water-binder ratios of W / B-0.4, W / B-0.5, and W / B-0.6 were obtained respectively. The obtained steel slag-based foamed concretes with W / B-0.4, W / B-0.5, and W / B-0.6 were poured into a 100 mm × 100 mm × 100 mm triple cube mold, covered with plastic wrap and placed indoors for curing for 2 days (curing parameters: temperature 20°C, relative humidity maintained at 60%). After demolding, the demolded samples were placed in a standard curing room for curing until 28 days (the process parameters controlled by standard curing: temperature 20°C, relative humidity 98%). According to "Foamed Concrete" JG / T 266-2011, their 28-day compressive strength and dry density were tested, and the test results are shown in Figure 10 .

[0187] It can be seen from Figure 10 that for the foamed concretes with a steel slag replacement ratio of 40% prepared with different water-binder ratios (0.4, 0.5, 0.6, and the water-binder ratio is the ratio of the mass of water to the sum of the masses of steel slag powder and cement), the data of their compressive strength and dry density show that as the water-binder ratio increases, the compressive strength significantly decreases from 8.50 MPa to 3.61 MPa, and the dry density decreases from 1554.28 kg / m 3 to 1237.48 kg / m 3 simultaneously. This may be attributed to the fact that at a low water-binder ratio (0.4), the concentration of the cementitious material is high, and the hydration reaction and carbonization reaction may be more complete, generating more C-S-H gels and dense CaCO3, improving the matrix density, with a compressive strength reaching 8.50 MPa and a dry density of 1554.28 kg / m 3; At the same time, the workability of the paste with a low water-binder ratio is worse, and more foam is lost when mixed with foam, resulting in an increase in dry density. At a high water-binder ratio (0.6), the excessive water dilutes the cementitious material, leading to a reduction in hydration products and an increase in porosity, and the strength and density decrease simultaneously, but its strength is still slightly higher than that of the foam concrete in the conventional experiment. It can be seen that the gradient design of strength and density can be achieved by precisely controlling the water-binder ratio to meet the diverse engineering requirements.

[0188] Through comprehensive evaluation, the present invention determines that the replacement amount of 40% steel slag powder is the relatively optimal mixing ratio scheme, that is, the scheme in Example 3. Under this scheme, the foam concrete has a compressive strength of 5.47 MPa and a dry density of 1297.94 kg / m 3 . While ensuring the engineering performance, significant solid waste resource utilization benefits are achieved. The main reasons for selecting this mixing ratio are as follows: First, the solid waste utilization is maximized on the premise of ensuring the structural performance; second, the strength, density requirements and environmental protection benefits are better balanced; third, compared with higher replacement amounts, the degree of strength attenuation is within a controllable range. At the same time, it is recommended to use a water-binder ratio of 0.5 to obtain the most suitable combination of workability and mechanical properties. This preferred scheme provides reliable technical support for the engineering application of steel slag in foam concrete.

[0189] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing solid waste-based foamed concrete, characterized in that: The following steps are involved: Providing a stirring device; Add water, solid waste powder and cement into a stirring device for pre-mixing; After the pre-stirring is completed, the stirring device is evacuated, and then CO2 is introduced into the stirring device for carbonization stirring; mixing a foaming agent with water to obtain a foaming liquid; Adding the foaming liquid into a foaming machine for foaming to obtain foam; After the carbonization mixing is completed, the CO2 in the mixing device is discharged by releasing the pressure, and then foam is added to the mixing device and mixed again to obtain solid waste-based foam concrete.

2. The method for preparing solid waste-based foamed concrete according to claim 1, characterized in that: The solid waste powder includes at least one of steel slag powder, slag powder and bottom ash; In the step of adding water, solid waste powder and cement to a stirring device, the mass ratio of water, solid waste powder and cement is (40-60):(0-100):(0-100); The ratio of the mass of water to the sum of the mass of solid waste powder and cement is (40-60):

100.

3. The method for preparing solid waste-based foamed concrete according to claim 1, characterized in that: The foaming agent includes surfactant foaming agent, protein foaming agent, composite foaming agent and chemical foaming agent; The surfactant foaming agent includes at least one of a rosin resin surfactant and a synthetic surfactant; The protein foaming agent includes at least one of an animal protein foaming agent and a plant protein foaming agent; The composite foaming agent includes a protein and a surfactant composite foaming agent; Chemical foaming agents include aluminum powder; In the step of mixing a foaming agent with water to obtain a foaming solution, the mass ratio of the foaming agent to water is 1:(40-100); After the carbonization and stirring are completed, the CO2 in the stirring device is discharged by depressurization, and then foam is added to the stirring device. The mass of the added foam is 0.5-2% of the sum of the mass of the solid waste powder and the cement.

4. The method for preparing solid waste-based foamed concrete according to claim 1, characterized in that: Add solid waste powder and cement into a stirring device and stir for 1 to 3 minutes, then add water and continue stirring for 1 to 3 minutes to complete pre-mixing; After the pre-stirring is completed, the stirring device is evacuated, and then CO2 is introduced into the stirring device to make the CO2 pressure in the stirring device 0.01MPa-0.5MPa, and then stirred at 100-120r / min for 0.5min-2min, and then stirred at 40-80r / min for 0.5-2min to complete the carbonization stirring; After the carbonization stirring is completed, release the pressure and discharge the CO2 in the stirring device, then add foam to the stirring device, stir at 40-80r / min for 0.5-1min, then stir at 90-120r / min for 10s-15s, stir at 40r / min-80r / min for 10s-15s, stir at 90-120r / min for 10s-15s, finally stir at 40-80r / min for 0.5-1min.

5. The method for preparing solid waste-based foamed concrete according to claim 1, characterized in that: The total mass fraction of SiO2, Al2O3 and CaO in the solid waste powder is ≥ 60%; The solid waste powder has a mesh size of ≥200 mesh; After the carbonization and stirring are completed, the CO2 in the stirring device is depressurized and discharged and introduced into the CO2 adsorbent to absorb the remaining unreacted CO2 for reuse.

6. The method for preparing solid waste-based foamed concrete according to claim 1, characterized in that: After obtaining the solid waste-based foamed concrete, the method also includes pouring the solid waste-based foamed concrete into a mold, covering it with a plastic wrap and curing it indoors for 2 to 3 days, demolding it, and then placing the demolded sample in a standard curing room for curing for 25 to 30 days.

7. The method for preparing solid waste-based foamed concrete according to claim 1, characterized in that: The stirring device comprises: A tank body, in which a stirring mechanism is provided; A cover plate, on which a CO2 inlet pipe and a vacuum pipe are arranged; the CO2 inlet pipe is connected to the CO2 gas cylinder and is used to introduce CO2 into the tank body; the cover plate is screwed on the tank body, and a sealing ring is arranged at the connection between the cover plate and the tank body; A lifting mechanism, used for lifting the cover plate to cover the cover plate on the tank body or to remove the cover plate from the tank body; The method for preparing the solid waste-based foamed concrete comprises the following steps: Add water, solid waste powder and cement into the tank, close the cover plate on the tank, and start the stirring mechanism for pre-stirring; After the pre-mixing is completed, the tank is evacuated and CO2 is introduced into the tank using a CO2 cylinder for carbonization mixing; mixing a foaming agent with water to obtain a foaming liquid; Adding the foaming liquid into a foaming machine for foaming to obtain foam; After the carbonization mixing is completed, the CO2 in the tank is discharged by releasing the pressure, and then foam is added into the tank and mixed again to obtain solid waste-based foam concrete.

8. The method for preparing solid waste-based foamed concrete according to claim 7, characterized in that: The stirring mechanism comprises: A stirring motor, located on the cover plate; A reducer is located on the cover plate, and the rotating shaft of the stirring motor is connected to the reducer; A stirring shaft is located in the tank body; A mechanical seal shaft, the upper end of which is connected to the shaft of the reducer, and the lower end of which passes through the cover plate and is connected to the stirring shaft; A stirring paddle is located in the tank body, and the stirring paddle is connected to the stirring shaft.

9. The method for preparing solid waste-based foamed concrete according to claim 7, characterized in that: The lifting mechanism comprises: Bracket; A first hanging member, which is arranged on the cover plate; A second hanging member, which is arranged on the bracket; A cable, one end of which is connected to the first hanging member, and the other end of which passes through the second hanging member and is connected to the driving member; Wherein, the driving member is used to drive the cover plate to move up and down in the vertical direction.

10. The method for preparing solid waste-based foamed concrete according to claim 7, characterized in that: The cover plate is provided with a pressure gauge; The cover plate is provided with a safety pressure relief pipe, and the safety pressure relief pipe is provided with a pressure relief valve; The cover plate is also provided with a transparent observation window; The CO2 intake pipe is provided with an intake valve; The vacuum tube is provided with an exhaust valve.

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