Aerated concrete products based on high methylene blue value tailings and their preparation methods

Abstract

This invention provides an aerated concrete product based on high methylene blue value tailings and its preparation method, comprising the following components by mass: 60-80 parts tailings, 10-20 parts cement, 5-10 parts lime, 6-8 parts waste aerated concrete, 4 parts desulfurized gypsum, 0.05 parts aluminum powder paste, and a composite admixture. The composite admixture includes a composite mud inhibitor, a water-reducing agent, and a composite early-strength agent, accounting for 2.9% of the total mass of cement and lime. The methylene blue value of the tailings is greater than 6. This invention, through optimized formulation design and the combined action of the composite admixture, greatly eliminates the adverse effects of high methylene blue value tailings on various stages of aerated concrete preparation, resulting in a uniform pore structure and high closed-pore rate. Even with a methylene blue value of over 6 and a tailings content of over 70%, the aerated concrete prepared using a shorter, energy-saving 6-hour steam curing regime still exhibits advantages such as good appearance quality, high strength, good volume stability, and excellent frost resistance.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to an aerated concrete product based on high methylene blue value tailings and its preparation method. Background Technology

[0002] In recent years, manufactured sand, which replaces river sand and sea sand, has become widely used and has played a positive role in protecting the environment; however, the waste generated from the production of manufactured sand has not been effectively utilized.

[0003] The tailings generated during stone processing typically contain a large amount of stone powder (SiO2 content ≥60%). Traditional disposal methods mainly involve landfilling, which leads to resource waste and environmental pollution. Autoclaved aerated concrete (AAC) is a lightweight, porous building material. Traditional processes use fly ash, sand, cement, and lime as the main raw materials. However, the supply of raw materials such as fly ash is limited, and the high stone powder content of the tailings has not been effectively utilized.

[0004] In existing technologies, the use of high-methylene blue value tailings is quite challenging. Due to their high clay content, they affect the stability of processes such as mixing, pouring, aeration, pre-curing, and autoclaving of aerated concrete. Directly using them as raw materials to produce aerated concrete products easily leads to problems such as aeration failure, mold collapse, pre-curing cracking, product cracking upon exiting the autoclave, low strength, high shrinkage, and poor frost resistance. Therefore, a targeted formulation and process optimization solution is urgently needed. Summary of the Invention

[0005] The purpose of this invention is to provide an aerated concrete product based on high methylene blue value tailings, which can at least solve some of the defects existing in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] Aerated concrete products based on high methylene blue value tailings include the following components by mass: 60-80 parts tailings, 10-20 parts cement, 5-10 parts lime, 6-8 parts waste aerated concrete, 4 parts desulfurized gypsum, 0.05 parts aluminum powder paste, and composite admixtures; the composite admixtures include composite mud inhibitors, water-reducing agents, and composite early-strength agents, the composite admixtures account for 2.9% of the total mass of cement and lime, and the methylene blue value of the tailings is greater than 6.

[0008] Furthermore, the tailings include stone powder, montmorillonite, kaolin, diatomite and illite, the methylene blue value of the tailings is 6.39-10.19 and the tailings particle size is 15-40 μm.

[0009] Furthermore, the mass ratio of the composite mud inhibitor, water-reducing agent, and composite early-strength agent is (2-3):0.5:1.

[0010] Furthermore, the composite mud inhibitor is composed of an aqueous polymer, gallic acid, and diethylene glycol, and the mass ratio of the aqueous polymer, gallic acid, and diethylene glycol is 10:5:3.

[0011] Furthermore, the water-reducing agent is a polycarboxylate superplasticizer.

[0012] Furthermore, the composite early strength agent is composed of sodium carbonate and calcium sulfoaluminate, and the mass ratio of sodium carbonate to calcium sulfoaluminate is 1:2.

[0013] Furthermore, the mass ratio of the waste aerated concrete to the tailings is 1:(9-10).

[0014] Furthermore, the mass ratio of cement to lime is (2-3):1.

[0015] Furthermore, the lime contains ≥70% calcium oxide, the desulfurized gypsum has a moisture content ≤10%, and the waste aerated concrete has a 200-mesh sieve residue ≤15.0%.

[0016] In addition, the present invention also provides a method for preparing the above-mentioned aerated concrete products based on high methylene blue value tailings, comprising the following steps:

[0017] S1. Dry and grind the waste aerated concrete.

[0018] S2. Weigh the tailings, cement, lime, waste aerated concrete, desulfurized gypsum and composite admixture according to the design ratio, add water and stir to mix evenly to obtain a mixed slurry.

[0019] S3. Pour the designed amount of aluminum powder paste into the mixed slurry and stir quickly;

[0020] S4. Pour the mixed slurry processed in step S3 into a mold, pre-cur it at 45-60℃, then demold and cut it to obtain a blank of a fixed size. Place the blank in an autoclave for autoclaving. The autoclaving time is 6 hours, the temperature is 180-195℃, and the pressure is 1.0-1.3MPa. After autoclaving, remove the aerated concrete from the autoclave to obtain the aerated concrete product.

[0021] In this invention, the main raw materials such as cement, lime, waste aerated concrete, tailings, desulfurized gypsum, composite mud inhibitor, water-reducing agent, and composite early strength agent participate in the reaction according to the designed proportions, and the reaction products are mainly tobermorite, hydrated garnet, and hydrated calcium silicate.

[0022] When high methylene blue tailings are used as raw materials for aerated concrete products, only a small portion of the stone powder in the tailings can be used as micro-aggregate filler to refine the internal pore structure. The majority of the stone powder and clay minerals will hinder the bonding between cement paste and aggregate, inhibit hydration, increase the water-to-material ratio, increase capillary pores, and deteriorate the pore structure. More seriously, the layered structure of clay powder is loose and porous with good water absorption. During curing and drying, it absorbs and loses a lot of water, resulting in obvious shrinkage and swelling. Therefore, using it directly as a raw material to produce aerated concrete products can easily lead to problems such as air trapping, mold collapse, cracking during pre-curing and after autoclaving, low strength, high shrinkage, and poor frost resistance. Based on this, this invention designs a composite mud inhibitor, a water-reducing agent, and a composite early-strength agent to achieve a synergistic effect of multiple admixtures to eliminate the adverse effects of high methylene blue value tailings. The mechanism is as follows: 1. The composite mud inhibitor combines charge neutralization, dispersion, and stabilization functions. The aqueous polymer in the composite mud inhibitor reduces the clay activity of the tailings through adsorption, while gallic acid can fix the free ions in the tailings through complexation, reducing interference with the performance of aerated concrete; 2. Diethylene glycol in the composite mud inhibitor helps to uniformly disperse other mud-inhibiting components through physical dispersion, improving the overall effect. Furthermore, the moisturizing and lubricating properties of diethylene glycol can reduce the absorption of water by the clay in the tailings, maintaining the fluidity of the aerated concrete. Simultaneously, the hydroxyl groups of diethylene glycol can interact with the clay surface of the tailings to form a protective layer, inhibiting clay expansion and water adsorption. Moreover, diethylene glycol can synergistically enhance the complexation effect with gallic acid; 3. The polycarboxylate superplasticizer can reduce the water-to-material ratio of the system and reduce the gross volume. Fine porosity makes the structure denser and promotes the dispersion of cement particles and early hydration, thereby weakening the adverse effects of clay minerals in tailings on the system; 4. Using a composite early strength agent of sodium carbonate and calcium sulfoaluminate as a reinforcing raw material, the calcium carbonate and a large amount of ettringite generated by the rapid hydration of sodium carbonate and calcium sulfoaluminate can provide a skeleton structure for cement paste, promote the setting of cement paste, and improve the early strength of aerated concrete. Moreover, the generated calcium carbonate has extremely high activity and can play a stabilizing role for AFT (ettringite), further enhancing the early strength and stabilizing the green body, thus solving many problems in the gas generation stage. The generated sodium hydroxide and aluminum hydroxide can increase the pH value of the slurry and promote the hydration reaction; Combining the above effects of the composite admixture, using this composite admixture can eliminate the adverse effects of tailings as raw materials for preparing aerated concrete, thus not only solving the problem of mismatch between early gas generation and hardening / thickening, but also solving the problem of poor physical and mechanical properties in the later stage.

[0023] In addition, the main XRD components of the waste aerated concrete in this invention are hydrated calcium silicate and tobermorite. These components can act as crystal nuclei to promote the reaction and generate hydrated calcium silicate and tobermorite, fill some micropores, and utilize their loose and porous structure to act as a bridge and adsorption between the products and raw materials. This allows the reaction products and unreacted tailings to be connected into a complete whole, further enhancing the structural density and enabling the solid waste to exhibit excellent performance.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention, through optimized formulation design and the combined action of composite admixtures, greatly eliminates the adverse effects of high methylene blue value tailings on various stages of aerated concrete preparation. This results in a uniform pore structure and a high closed porosity, enabling the final aerated concrete to possess advantages such as good appearance quality, high strength, good volume stability, and excellent frost resistance, even when the methylene blue value of the tailings is as high as 6 or above and the tailings content is as high as 70%, using a shorter 6-hour energy-saving steam curing regime. This meets the requirements of building performance and application parameters, significantly reducing the cost of aerated concrete products and production energy consumption.

[0026] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0027] Figure 1 This is a photograph of the aerated concrete product prepared in Example 3 of the present invention after it has been removed from the autoclave and dried.

[0028] Figure 2 This is a photograph of the aerated concrete product prepared in Comparative Example 1 of the present invention after it has been removed from the autoclave and dried. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention provides an aerated concrete product based on high methylene blue value tailings, comprising the following components by mass: 60-80 parts tailings, 10-20 parts cement, 5-10 parts lime, 6-8 parts waste aerated concrete, 4 parts desulfurized gypsum, 0.05 parts aluminum powder paste, and a composite admixture; the composite admixture includes a composite mud inhibitor, a water-reducing agent, and a composite early-strength agent, the composite admixture accounting for 2.9% of the total mass of cement and lime, and the methylene blue value of the tailings is greater than 6.

[0031] Specifically, conventional tailings generally contain mainly stone powder and have a low methylene blue value. However, the tailings of this invention, in addition to stone powder, also contain a significant amount of clay minerals. The main components of these clay minerals include montmorillonite (3-5% of the tailings mass), kaolin (5-10% of the tailings mass), diatomite (5-10% of the tailings mass), and illite (5-10% of the tailings mass). The presence of a certain amount of montmorillonite in the tailings results in a higher methylene blue value. With a methylene blue value of 6.39-10.19, using this type of tailings directly as raw material to prepare aerated concrete products can easily lead to problems such as gas generation and entrapment, mold collapse, pre-curing cracking and product cracking after exiting the autoclave, low strength, large shrinkage rate, and poor frost resistance. Therefore, this invention designs a composite admixture, utilizing the synergistic effect of the composite mud inhibitor, water-reducing agent, and composite early-strength agent to eliminate the adverse effects of using high methylene blue value tailings directly as raw materials for preparing aerated concrete products. The tailings particle size is 15-40μm.

[0032] Specifically, the mass ratio of the composite mud inhibitor, water-reducing agent, and composite early-strength agent is (2-3):0.5:1; the composite mud inhibitor is composed of an aqueous polymer, gallic acid, and diethylene glycol, and the mass ratio of the aqueous polymer, gallic acid, and diethylene glycol is 10:5:3. Preferably, the aqueous polymer is a polymer synthesized from alkenyl amine ether and (meth)acrylate monomer; the water-reducing agent is a polycarboxylate high-efficiency water-reducing agent; the composite early-strength agent is composed of sodium carbonate and calcium sulfoaluminate, and the mass ratio of sodium carbonate and calcium sulfoaluminate is 1:2.

[0033] Specifically, the cement used is Huaxin Pu Si 42.5 cement, the lime contains ≥70% calcium oxide, and the mass ratio of cement to lime is (2-3):1; the desulfurized gypsum has a moisture content ≤10%; the waste aerated concrete is ground, and the waste aerated concrete has a residue of ≤15.0% after passing through a 200-mesh sieve, and the mass ratio of waste aerated concrete to tailings is 1:(9-10).

[0034] The preparation process and performance of aerated concrete products based on high methylene blue value tailings are illustrated below through specific embodiments.

[0035] Example 1:

[0036] This embodiment provides an aerated concrete product based on high methylene blue value tailings, comprising the following components by mass: 60 parts tailings, 12 parts cement, 6 parts lime, 6 parts waste aerated concrete, 4 parts desulfurized gypsum, 0.05 parts aluminum powder paste, and a composite admixture. The composite admixture includes a composite mud inhibitor, a water-reducing agent, and a composite early-strength agent. The composite admixture accounts for 2.9% of the total mass of cement and lime, and the mass ratio of the composite mud inhibitor, water-reducing agent, and composite early-strength agent is 2:0.5:1. The composite mud inhibitor is composed of an aqueous polymer, gallic acid, and diethylene glycol in a mass ratio of 10:5:3. The aqueous polymer is a polymer synthesized from alkenylamine ether and (meth)acrylate monomers. The water-reducing agent is a polycarboxylate high-efficiency water-reducing agent, and the composite early-strength agent is composed of sodium carbonate and calcium sulfoaluminate in a mass ratio of 1:2.

[0037] The preparation process of the above-mentioned aerated concrete products based on high methylene blue value tailings is as follows:

[0038] First, the waste aerated concrete is dried and then processed in a ball mill, with the residue passing through a 200-mesh sieve being ≤15.0%.

[0039] Then, weigh the tailings, cement, lime, waste aerated concrete, desulfurized gypsum, composite mud inhibitor, water-reducing agent and composite early strength agent according to the above proportions, add water and mix evenly for 3 minutes at a stirring speed of 1200 rpm to obtain a mixed slurry; then pour in aluminum powder paste and stir quickly for 50 seconds.

[0040] Finally, the mixed slurry is poured into the mold and pre-cured at 45℃ for 4 hours. After demolding, the green body is cut to obtain a fixed size. The green body is then placed in an autoclave for autoclaving. The autoclaving time is 6 hours, the temperature is 180℃, and the pressure is 1.0MPa. After autoclaving, the aerated concrete is removed from the autoclave, thus obtaining the aerated concrete product based on high methylene blue value tailings.

[0041] Example 2:

[0042] This embodiment provides an aerated concrete product based on high methylene blue value tailings, comprising the following components by mass: 63 parts tailings, 15 parts cement, 5 parts lime, 7 parts waste aerated concrete, 4 parts desulfurized gypsum, 0.05 parts aluminum powder paste, and a composite admixture. The composite admixture includes a composite mud inhibitor, a water-reducing agent, and a composite early-strength agent. The composite admixture accounts for 2.9% of the total mass of cement and lime, and the mass ratio of the composite mud inhibitor, water-reducing agent, and composite early-strength agent is 2.5:0.5:1. The composite mud inhibitor is composed of an aqueous polymer, gallic acid, and diethylene glycol in a mass ratio of 10:5:3. The aqueous polymer is a polymer synthesized from alkenylamine ether and (meth)acrylate monomers. The water-reducing agent is a polycarboxylate high-efficiency water-reducing agent, and the composite early-strength agent is composed of sodium carbonate and calcium sulfoaluminate in a mass ratio of 1:2.

[0043] The preparation process of the above-mentioned aerated concrete products based on high methylene blue value tailings is as follows:

[0044] First, the waste aerated concrete is dried and then processed in a ball mill, with the residue passing through a 200-mesh sieve being ≤15.0%.

[0045] Then, weigh the tailings, cement, lime, waste aerated concrete, desulfurized gypsum, composite mud inhibitor, water-reducing agent and composite early strength agent according to the above proportions, add water and mix evenly for 3 minutes at a stirring speed of 1200 rpm to obtain a mixed slurry; then pour in aluminum powder paste and stir quickly for 50 seconds.

[0046] Finally, the mixed slurry is poured into the mold and pre-cured at 50℃ for 4 hours. After demolding, the mold is cut to obtain a blank of a fixed size. The blank is then placed in an autoclave for autoclaving. The autoclaving time is 6 hours, the temperature is 180℃, and the pressure is 1.0MPa. After autoclaving, the aerated concrete is removed from the autoclave, thus obtaining the aerated concrete product based on high methylene blue value tailings.

[0047] Example 3:

[0048] This embodiment provides an aerated concrete product based on high methylene blue value tailings, comprising the following components by mass: 80 parts tailings, 20 parts cement, 10 parts lime, 8 parts waste aerated concrete, 4 parts desulfurized gypsum, 0.05 parts aluminum powder paste, and a composite admixture. The composite admixture includes a composite mud inhibitor, a water-reducing agent, and a composite early-strength agent. The composite admixture accounts for 2.9% of the total mass of cement and lime, and the mass ratio of the composite mud inhibitor, water-reducing agent, and composite early-strength agent is 3:0.5:1. The composite mud inhibitor is composed of an aqueous polymer, gallic acid, and diethylene glycol in a mass ratio of 10:5:3. The aqueous polymer is a polymer synthesized from alkenylamine ether and (meth)acrylate monomers. The water-reducing agent is a polycarboxylate high-efficiency water-reducing agent, and the composite early-strength agent is composed of sodium carbonate and calcium sulfoaluminate in a mass ratio of 1:2.

[0049] The preparation process of the above-mentioned aerated concrete products based on high methylene blue value tailings is as follows:

[0050] First, the waste aerated concrete is dried and then processed in a ball mill, with the residue passing through a 200-mesh sieve being ≤15.0%.

[0051] Then, weigh the tailings, cement, lime, waste aerated concrete, desulfurized gypsum, composite mud inhibitor, water-reducing agent and composite early strength agent according to the above proportions, add water and mix evenly for 3 minutes at a stirring speed of 1200 rpm to obtain a mixed slurry; then pour in aluminum powder paste and stir quickly for 50 seconds.

[0052] Finally, the mixed slurry is poured into the mold and pre-cured at 60℃ for 4 hours. After demolding, the green body is cut to obtain a fixed size. The green body is then placed in an autoclave for autoclaving. The autoclaving time is 6 hours, the temperature is 195℃, and the pressure is 1.3MPa. After autoclaving, the aerated concrete is removed from the autoclave, thus obtaining the aerated concrete product based on high methylene blue value tailings.

[0053] The aerated concrete product prepared in this embodiment is shown in the photo after being removed from the autoclave and dried. Figure 1 As shown, by Figure 1 It can be seen that the aerated concrete products prepared in this embodiment have good appearance quality and no obvious cracks.

[0054] Comparative Example 1:

[0055] This comparative example provides an aerated concrete product whose composition is basically the same as that of the aerated concrete product in Example 3 above. The difference is that the aerated concrete product of this comparative example does not contain composite admixtures and waste aerated concrete. That is, the aerated concrete product of this comparative example includes the following components by weight: 80 parts tailings, 20 parts cement, 10 parts lime, 4 parts desulfurized gypsum, and 0.05 parts aluminum powder paste.

[0056] The preparation process of the aerated concrete product in this comparative example is as follows:

[0057] First, weigh out cement, lime, tailings, desulfurized gypsum, and aluminum powder paste according to the above proportions, add water, and mix evenly at a stirring speed of 1200 rpm to obtain a mixed slurry.

[0058] Then, the mixture slurry is poured into the mold and pre-cured at 60℃ for 4 hours. After demolding, it is cut to obtain a blank of a fixed size. The blank is placed in an autoclave for autoclaving. The autoclaving time is 8 hours, the temperature is 195℃, and the pressure is 1.3MPa. After autoclaving, the aerated concrete is removed from the autoclave to obtain the aerated concrete product.

[0059] The aerated concrete products prepared in this comparative example are shown in the photo after being removed from the autoclave and dried. Figure 2 As shown, by Figure 2 It can be seen that obvious cracks appeared on the surface of the aerated concrete products prepared in this comparative example.

[0060] Therefore, in comparison Figure 1 and Figure 2 It can be concluded that the addition of composite admixtures and waste aerated concrete in this invention plays a crucial role in eliminating cracking in aerated concrete products prepared by directly using high methylene blue value tailings as raw materials.

[0061] The physical and mechanical properties of the aerated concrete products prepared in Examples 1, 2, and 3 and Comparative Example 1 were tested, and the results are shown in Table 1.

[0062] Table 1:

[0063] detection indicators Example 1 Example 2 Example 3 Comparative Example 1 Density grade B06 B06 B06 B06 Compressive strength (MPa) 8.31 7.85 8.52 3.28 Freeze resistance - mass loss (%) 0.40 0.68 0.31 7.02 Freeze-thaw resistance - strength loss (%) 5.96 7.35 5.48 25.19

[0064] Example 4:

[0065] This embodiment investigated the effect of the cement-to-lime ratio on the performance of the prepared aerated concrete. To demonstrate the difference in the effect of the cement-to-lime ratio on the performance of the aerated concrete, three groups of experiments (Group A, Group B, and Group C) were designed for comparison. Group A used the formula of Example 3 (i.e., cement:lime = 2:1), Group B contained 20 parts cement and 5 parts lime (i.e., cement:lime = 4:1), with the remaining components the same as Group A, and Group C contained 15 parts cement and 15 parts lime (i.e., cement:lime = 1:1), with the remaining components the same as Group A. The preparation process of the aerated concrete in Groups A, B, and C in this embodiment was consistent with that in Example 3. The physical and mechanical properties of the aerated concrete prepared in Groups A, B, and C in this embodiment were tested, and the results are shown in Table 2.

[0066] Table 2:

[0067]

[0068]

[0069] As shown in Table 2, among the aerated concrete prepared using the same molding process, Group A, with a cement-to-lime ratio of 2:1, produced the aerated concrete with the highest compressive strength of 8.52 MPa. Furthermore, its freeze-thaw resistance test demonstrated that the aerated concrete of this invention maintained its integrity after 15 freeze-thaw cycles, with a mass loss rate of only 0.31% and a compressive strength loss rate of only 5.48%. Both physical and mechanical properties significantly exceeded the requirements for aerated concrete in GB / T11969-2020. In contrast, Groups B and C, with cement-to-lime ratios of 4:1 and 1:1 respectively, exhibited lower compressive strength and poorer freeze-thaw resistance. Therefore, the cement-to-lime ratio plays a crucial role in the performance of aerated concrete.

[0070] Example 5:

[0071] This embodiment investigated the effect of the ratio of waste aerated concrete to tailings on the performance of the prepared aerated concrete. To demonstrate the difference in the effect of the ratio of waste aerated concrete to tailings on the performance of aerated concrete, three groups of experiments (Group A, Group B, and Group C) were designed for comparison. Group A used the formula of Example 3 (i.e., waste aerated concrete: tailings = 1:10). Group B contained 8 parts waste aerated concrete and 64 parts tailings (i.e., waste aerated concrete: tailings = 1:8), with the remaining components the same as Group A. Group C contained 8 parts waste aerated concrete and 88 parts tailings (i.e., waste aerated concrete: tailings = 1:11), with the remaining components the same as Group A. The preparation process of the aerated concrete in Groups A, B, and C in this embodiment was consistent with that in Example 3. The physical and mechanical properties of the aerated concrete prepared in Groups A, B, and C in this embodiment were tested, and the results are shown in Table 3.

[0072] Table 3:

[0073]

[0074]

[0075] As shown in Table 3, among the aerated concrete blocks prepared using the same molding process, the aerated concrete in Group A, with a waste aerated concrete to tailings ratio of 1:10, exhibited the highest compressive strength of 8.52 MPa. Furthermore, its freeze-thaw resistance test demonstrated that the aerated concrete of this invention maintained its integrity after 15 freeze-thaw cycles, with a mass loss rate of only 0.31% and a compressive strength loss rate of only 5.48%. Both physical and mechanical properties significantly exceeded the requirements for aerated concrete in GB / T11969-2020. In contrast, the aerated concrete in Groups B and C, with waste aerated concrete to tailings ratios of 1:8 and 1:11 respectively, showed lower compressive strength and poorer freeze-thaw resistance. Therefore, the ratio of waste aerated concrete to tailings plays a crucial role in the performance of aerated concrete.

[0076] Example 6:

[0077] This embodiment investigated the effect of admixtures on the performance of prepared aerated concrete. To demonstrate the differences in the effects of admixtures on the performance of aerated concrete, this embodiment designed 11 groups of experiments for comparison: Group A, Group B, Group C, Group D, Group E, Group F, Group G, Group H, Group I, Group J, and Group K. The admixtures were identical except for their type and composition. Group A used the formulation from Example 3 above; Group B did not contain a composite mud inhibitor, but the remaining components were the same as Group A; Group C used a low-molecular-weight polymer mud inhibitor, and the remaining components were the same as Group A. Similarly, Group D contains no water-reducing agent, and the remaining components are the same as Group A; Group E uses a naphthalene-based high-efficiency water-reducing agent, and the remaining components are the same as Group A; Group F contains no composite early-strength agent, and the remaining components are the same as Group A; Group G uses a triisopropanolamine early-strength agent, and the remaining components are the same as Group A; Group H contains only a composite mud inhibitor, and the remaining components are the same as Group A; Group I contains only a water-reducing agent (polycarboxylate high-efficiency water-reducing agent), and the remaining components are the same as Group A; Group J contains only a composite early-strength agent, and the remaining components are the same as Group A; Group K contains no composite admixture, and the remaining components are the same as Group A. In this embodiment, the preparation process of aerated concrete for Groups A, B, C, D, E, F, G, H, I, J, and K is consistent with that in Example 3 above. The physical and mechanical properties of the aerated concrete prepared in 11 groups (A, B, C, D, E, F, G, H, I, J, and K) in this embodiment were tested, and the results are shown in Table 4.

[0078] Table 4:

[0079] Density grade Compressive strength (MPa) Freeze resistance - mass loss (%) Freeze-thaw resistance - strength loss (%) Group A B06 8.52 0.31 5.48 Group B B06 5.11 3.78 15.89 Group C B06 7.15 0.81 10.21 Group D B06 6.47 2.03 11.02 Group E B06 6.98 2.50 13.55 Group F B06 5.71 3.34 15.13 Group G B06 6.75 2.98 13.48 Group H B06 5.11 3.89 15.81 Group I B06 4.24 4.44 17.56 Group J B06 4.76 4.05 16.18 Group K B06 3.72 6.24 24.56

[0080] As shown in Table 4, the aerated concrete test results indicate that the aerated concrete prepared using the composite admixture of this invention exhibits the highest compressive strength. Furthermore, its freeze-thaw resistance test demonstrates that the aerated concrete of this invention maintains the integrity of the aerated blocks after 15 freeze-thaw cycles, with a mass loss rate of only 0.31% and a compressive strength loss rate of only 5.48%. Both physical and mechanical properties significantly exceed the requirements for aerated concrete in GB / T11969-2020. Comparative results show that the composite admixture used in this invention, comprising the composite mud inhibitor, water-reducing agent, and composite early-strength agent, has a synergistic effect. The absence of any one or two of these agents significantly reduces both compressive strength and freeze-thaw resistance. Moreover, the fact that groups C, E, and G, which used different mud inhibitors, water-reducing agents, and early-strength agents than those of this invention, showed a decrease in compressive strength and freeze-thaw resistance compared to the products of this invention, suggests that different types of admixtures have a significant impact on the performance of aerated concrete.

[0081] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. An aerated concrete product based on high methylene blue value tailings, characterized in that, The product comprises the following components by mass: 60-80 parts tailings, 10-20 parts cement, 5-10 parts lime, 6-8 parts waste aerated concrete, 4 parts desulfurized gypsum, 0.05 parts aluminum powder paste, and a composite admixture. The composite admixture includes a composite mud inhibitor, a water-reducing agent, and a composite early-strength agent, and the composite admixture accounts for 2.9% of the total mass of cement and lime. The tailings include stone powder, montmorillonite, kaolin, diatomite, and illite, with a methylene blue value of 6.39-10.19 and a particle size of 15-40 μm. The composite mud inhibitor is composed of a water-based polymer, gallic acid, and diethylene glycol, and the mass ratio of waste aerated concrete to tailings is 1:(9-10). The water-reducing agent is a polycarboxylate high-efficiency water-reducing agent, and the composite early-strength agent is composed of sodium carbonate and calcium sulfoaluminate, with a mass ratio of sodium carbonate to calcium sulfoaluminate of 1:

2.

2. The aerated concrete product based on high methylene blue value tailings as described in claim 1, characterized in that, The mass ratio of the composite mud inhibitor, water-reducing agent, and composite early-strength agent is (2-3):0.5:

1.

3. The aerated concrete product based on high methylene blue value tailings as described in claim 1 or 2, characterized in that, The mass ratio of the aqueous polymer, gallic acid, and diethylene glycol is 10:5:

3.

4. The aerated concrete product based on high methylene blue value tailings as described in claim 1, characterized in that, The mass ratio of cement to lime is (2-3):

1.

5. The aerated concrete product based on high methylene blue value tailings as described in claim 1, characterized in that, The lime contains ≥70% calcium oxide, the desulfurized gypsum has a moisture content ≤10%, and the waste aerated concrete has a 200-mesh sieve residue ≤15.0%.

6. The method for preparing aerated concrete products based on high methylene blue value tailings according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Dry and grind the waste aerated concrete. S2. Weigh the tailings, cement, lime, waste aerated concrete, desulfurized gypsum and composite admixture according to the design ratio, add water and stir to mix evenly to obtain a mixed slurry. S3. Pour the designed amount of aluminum powder paste into the mixed slurry and stir quickly; S4. Pour the mixed slurry processed in step S3 into a mold, pre-cur it at 45-60℃, then demold and cut it to obtain a blank of a fixed size. Place the blank in an autoclave for autoclaving. The autoclaving time is 6 hours, the temperature is 180-195℃, and the pressure is 1.0-1.3MPa. After autoclaving, remove the aerated concrete from the autoclave to obtain the aerated concrete product.

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