Aerated block of carbide slag and fly ash concrete and its preparation method

Abstract

This invention discloses an aerated concrete block made of carbide slag and fly ash, and its preparation method, in the field of building materials and solid waste resource utilization technology. The raw materials for this aerated block include carbide slag, fly ash, gypsum, silicate cement, aluminum powder paste, a nano-core-shell structured calcium aluminum silicate polymer, and a zwitterionic foam-stabilizing polymer, each with a specific weight range. The nano-core-shell structured calcium aluminum silicate polymer is prepared by dispersing fly ash in water to form a slurry, which is then reacted sequentially with sodium silicate and sodium aluminate solutions, followed by the addition of calcium nitrate and zinc sulfate solutions for further reaction. The mixture is then separated, washed, dried, and ground. The zwitterionic foam-stabilizing polymer is prepared by polymerizing monomers in a solvent, precipitating the precipitate, followed by quaternization, activated carboxyl crosslinking, dialysis purification, and freeze-drying. Each step involves process parameters such as dry mixing time, stirring time, curing temperature, pressure, and time. The performance of the aerated block is improved through component optimization and process refinement.

Description

Technical Field

[0001] This invention relates to the field of building materials and solid waste resource utilization technology, specifically to an aerated concrete block made of carbide slag and fly ash and its preparation method. Background Technology

[0002] With the rapid development of the construction industry and the acceleration of urbanization, aerated concrete blocks, as a lightweight, heat-insulating, and earthquake-resistant new type of wall material, are widely used in residential and public buildings due to their excellent performance, and market demand continues to grow. However, the production of traditional aerated concrete blocks mainly relies on natural resources such as sand, gravel, and cement. Extensive mining not only leads to the depletion of mineral resources but also causes serious ecological damage and environmental pollution. At the same time, solid waste such as carbide slag and fly ash generated during industrial production is increasing year by year, occupying large amounts of land resources, and the leakage of some harmful components can pollute soil and water sources, posing a serious threat to the ecological environment. Against this backdrop, how to efficiently utilize industrial solid waste to replace some traditional raw materials in the preparation of high-performance building materials has become an important research direction for promoting the development of a circular economy and achieving the "dual carbon" goal. Therefore, the research and development of carbide slag and fly ash aerated concrete blocks has received widespread attention.

[0003] Currently, there are some attempts in the market to prepare aerated concrete blocks using calcium carbide slag and fly ash. Calcium carbide slag is an industrial waste residue from the hydrolysis of calcium carbide to produce acetylene. Its main component is calcium hydroxide. Although its high alkalinity and low activity can replace some cement to a certain extent, its direct use can easily lead to slow early strength development and unstable setting time of aerated blocks due to insufficient cementitious activity. Fly ash, as an emission from coal-fired power plants, contains a large amount of silicon and aluminum, but its pozzolanic activity needs to be activated by an activator to be effectively exerted. Traditional processes often use alkaline activators or sulfate activators alone, which have problems with low activation efficiency and weak synergistic effect, often resulting in limited fly ash content and difficulty in further improving the utilization rate of solid waste. In addition, the foaming process of aerated blocks has extremely high requirements for bubble stability. Traditional processes often use aluminum powder as a foaming agent, and its foaming rate is significantly affected by temperature and pH value, which easily leads to uneven bubble distribution, cross-holes, or mold collapse. This results in a loose internal structure and large fluctuations in density of the product, making it difficult to meet the technical requirements of high-strength aerated blocks. There is room for optimization in the curing process of existing processes. For example, an unreasonable autoclaving system may lead to incomplete development of the internal structure of the product, while an excessively long natural curing cycle will affect production efficiency. These factors together restrict the large-scale application and performance improvement of carbide slag fly ash concrete aerated blocks.

[0004] To address the aforementioned technical bottlenecks, recent research has focused on raw material modification and process optimization. Some studies have attempted to improve the activity of carbide slag and fly ash through mechanical grinding and chemical activation, but mechanical grinding suffers from high energy consumption and low efficiency, and the selection and proportioning of chemical activators still require systematic optimization. Other studies have proposed adding polymer admixtures to improve slurry fluidity or bubble stability, but existing admixtures are mostly single-functional, making it difficult to simultaneously meet multiple needs such as enhanced cementitious bonding, controlled foaming, and optimized pore structure. Furthermore, the preparation processes of some polymers are complex and costly, limiting their engineering applications. Against this backdrop, developing a carbide slag and fly ash concrete aerated block preparation technology that balances efficient solid waste utilization, stable and controllable performance, and simple process is of great significance for promoting the resource utilization of industrial solid waste, reducing the production cost of building materials, and improving the overall performance of products. Based on this need, this invention designs the preparation process of nano-core-shell structured calcium aluminum silicon polymer and zwitterionic foam-stabilized polymer, optimizes the raw material ratio and molding and curing process, and is expected to solve the problems of insufficient solid waste activity, poor foaming stability and large fluctuations in product performance in traditional technologies, providing a new technical path for the high-value application of calcium carbide slag and fly ash concrete aerated blocks. Summary of the Invention

[0005] The purpose of this invention is to provide a carbide slag and fly ash concrete aerated block and its preparation method, which solves the technical problems of insufficient solid waste cementitious activity, poor foaming stability, uneven product structure and low production efficiency of existing carbide slag and fly ash concrete aerated blocks.

[0006] The present invention achieves the above objectives through the following technical solutions:

[0007] An aerated concrete block made of carbide slag and fly ash comprises the following raw materials in parts by weight:

[0008] Calcium carbide slag: 150-300 parts by weight;

[0009] Fly ash: 600-750 parts by weight;

[0010] Gypsum: 20-50 parts by weight;

[0011] Silicate cement: 30-80 parts by weight;

[0012] Aluminum powder paste: 0.5-1.5 parts by weight;

[0013] Nanocore-shell structured calcium aluminum silicon polymer: 5-25 parts by weight;

[0014] Amphoteric foam stabilizer: 1-5 parts by weight;

[0015] The preparation method of the nano-core-shell structured calcium aluminum silicon polymer includes: A1, dispersing fly ash in deionized water to form a uniform slurry, adding sodium silicate solution and sodium aluminate solution under high-speed shear, adjusting the pH to 11-12, and reacting at 70-72℃; A2, subsequently adding calcium nitrate solution and zinc sulfate to the slurry, maintaining the reaction temperature at 80-84℃, and continuing the reaction; after the reaction is completed, centrifuging and washing with ethanol to terminate the reaction, and finally vacuum drying at 60-64℃, grinding and sieving.

[0016] In this invention, the preparation process of the nano-core-shell structured calcium-aluminum-silicon polymer is an ingenious interface engineering and biomimetic mineralization process. The reaction begins with the surface activation stage of fly ash particles. Under alkaline conditions, the silicate and aluminate ions provided by sodium silicate and sodium aluminate dissociate and recombine with the silicon-oxygen and aluminum-oxygen bonds on the fly ash surface, forming silanol and aluminum hydroxyl sites with higher reactivity. These newly formed active sites act as anchor points, laying the molecular foundation for subsequent mineralization deposition. The subsequently introduced calcium nitrate solution provides sufficient calcium ions. Under the crystal-guided effect of zinc sulfate, calcium ions do not precipitate randomly but are directionally adsorbed and arranged in an orderly manner on the surface of the fly ash particles. The zinc ions in zinc sulfate have unique amphoteric characteristics, capable of coordinating with silicate ions and synergizing with calcium ions, acting as a molecular template to guide the epitaxial growth of hydrated calcium silicate on the fly ash surface in the form of a nano-thin layer. This process simulates the controllable crystallization mechanism in biomineralization, ultimately forming a composite structure with fly ash as the core and nano-hydrated calcium silicate as the shell. This core-shell design greatly increases the specific surface area and reactivity of the material. When added to an aerated block system, these nano-core-shell particles become nucleation centers for the hydration reaction, accelerating the formation of hydrated calcium silicate gel and effectively improving the early strength development of the slurry.

[0017] According to a preferred embodiment of the present invention, in step A1, the reaction time is 2-4 hours at 70-72°C.

[0018] According to a preferred embodiment of the present invention, in step A2, the reaction time is 4-6 hours; the vacuum drying time at 60-64°C is 24-30 hours; and the material is ground through a 400-500 mesh sieve.

[0019] According to a preferred embodiment of the present invention, the preparation method of the zwitterionic foam stabilizer includes: B1, under nitrogen protection, using dimethyl sulfoxide as solvent, adding 2-(dimethylamino)ethyl methacrylate and 2-acrylamide-2-methylpropanesulfonic acid monomers; after stirring and dissolving, adding azobisisobutyronitrile, and reacting in an oil bath at 74-76°C to obtain a crude product; B2, adding the crude product dropwise to refractory ether for precipitation, filtering and collecting the white flocculent precipitate; redissolving the precipitate in deionized water, adding iodomethane, and reacting at 40-42°C; after the reaction, dialyzing through a dialysis bag to obtain a quaternized linear copolymer solution; adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide to the quaternized linear copolymer solution, then adding ethylenediamine, and stirring the reaction at room temperature; after the reaction, dialysis purification again, and finally freeze-drying.

[0020] In this invention, the synthesis of zwitterionic foam-stabilizing polymers is a multi-step molecular design and assembly process. First, a linear polymer backbone containing both tertiary amine and sulfonic acid groups is synthesized via free radical copolymerization; this backbone itself already possesses the rudiments of a zwitterionic structure. Subsequently, in a quaternization reaction, iodomethane undergoes a nucleophilic substitution reaction with the tertiary amine group, converting the tertiary amine into a quaternary ammonium salt cation. At this point, the polymer chain permanently carries both positive and negative charges, forming a true zwitterionic structure. This unique molecular structure gives it strong hydrophilicity and a unique anti-polyelectrolyte effect in aqueous solutions. The most crucial step is the cross-linking reaction. Ethylenediamine, as a bifunctional cross-linking agent, undergoes an amidation reaction between its amino groups and the carboxyl groups activated by the activator on the polymer chain, thereby constructing a stable three-dimensional network structure between different polymer chains. This cross-linked network not only improves the mechanical strength of the polymer but, more importantly, enables it to form a molecular film with high surface elasticity and viscosity at the gas-liquid interface. During the gasification process of the gas block, this zwitterionic polymer can be quickly adsorbed onto the interface of hydrogen bubbles. Its three-dimensional network structure can effectively resist liquid film drainage and gas diffusion. At the same time, its zwitterionic properties can resist the destruction caused by high calcium ion concentration in the system, thereby stabilizing the bubble structure and forming uniform and fine closed pores.

[0021] According to a preferred embodiment of the present invention, in step B1, the reaction time in the oil bath at 74-76°C is 8-10 hours.

[0022] According to a preferred embodiment of the present invention, in step B2, the reaction time at 40-42°C is 12-14 hours.

[0023] This invention also provides a method for preparing the aforementioned carbide slag fly ash concrete aerated block, comprising the following steps:

[0024] S1. Add carbide slag, fly ash, gypsum and silicate cement into a forced mixer and dry mix until uniform to obtain dry material; then, dissolve the nano-core-shell structured calcium aluminum silicon polymer and zwitterionic foam stabilizer polymer in water and stir thoroughly to form a modified aqueous solution;

[0025] S2. Pour the modified aqueous solution into a forced mixer and mix it with the dry materials to form a uniform slurry. Then, add aluminum powder paste to the slurry and stir at high speed to disperse it evenly. Pour the slurry into a mold pre-coated with a release agent and cure it at 60-64℃. After the green body hardens, demold it and cut it to obtain the green body.

[0026] S3. The cut blanks are sent into an autoclave and autoclaved under conditions of saturated steam pressure of 1.0-1.2MPa and temperature of 180-190℃; after exiting the autoclave, they are naturally cured.

[0027] In this invention, the preparation of aerated concrete blocks from carbide slag and fly ash is a complex process involving multiple components and stages working synergistically. In the initial mixing stage, the calcium hydroxide provided by the carbide slag reacts with the active silica-alumina components in the fly ash under alkaline conditions to undergo a pozzolanic reaction. Simultaneously, the addition of gypsum regulates the setting time and promotes the formation of ettringite. The addition of the nano-core-shell structured calcium-aluminum-silica polymer acts like countless miniature reactors; its surface nano-hydrated calcium silicate shell provides abundant nucleation sites, greatly accelerating the hydration reaction and enabling the slurry to quickly acquire early strength. At the same time, the zwitterionic foam-stabilizing polymer is fully dissolved and dispersed in the slurry. Its unique zwitterionic structure and three-dimensional network characteristics allow it to form a robust adsorption film at the gas-liquid interface. When the aluminum powder paste reacts with the alkaline environment to produce hydrogen gas, these bubbles are firmly stabilized by the elastic film formed by the zwitterionic polymer, forming uniformly distributed microbubbles. During the static curing stage, the nano-core-shell particles continue to promote the hydration reaction, ensuring sufficient strength for cutting. In the autoclaving stage, the high temperature and pressure conditions significantly accelerate the pozzolanic reaction, resulting in the formation of numerous well-crystallized tobermorite and other hydration products. These, along with the stable porous structure, constitute the final strength framework of the aerated concrete block. The three main components—carbide slag and fly ash matrix, nano-core-shell reinforcing agent, and zwitterionic foam stabilizer—work synergistically to ultimately create an aerated concrete block product with excellent mechanical properties, a uniform pore structure, and good durability.

[0028] According to a preferred embodiment of the present invention, in step S1, the dry mixing time is 3-5 min.

[0029] According to a preferred embodiment of the present invention, in step S2, the high-speed stirring time is 30-45s; the static curing time at 60-64℃ is 2-3h.

[0030] According to a preferred embodiment of the present invention, in step S3, the autoclaving time is 8-10 hours.

[0031] The beneficial effects of this invention are as follows:

[0032] This invention achieves significant results in solid waste utilization, performance improvement, and production efficiency through raw material system innovation and process optimization. In the efficient utilization of solid waste, the nano-core-shell structured calcium-aluminum-silicon polymer plays a key role. Its unique structure can directionally adsorb carbide slag particles, accelerate the dissolution of calcium hydroxide and provide active sites, while simultaneously stimulating the silicon-aluminum components in fly ash to participate in the pozzolanic reaction, forming a denser CSH gel network. This synergistic mechanism enhances the gelling activity of solid waste, significantly increasing the content of carbide slag and fly ash, effectively reducing the consumption of natural sand and gravel, and realizing the high-value utilization of industrial solid waste.

[0033] In terms of product performance, the zwitterionic foam-stabilizing polymer stabilizes the bubble surface through positive and negative charged groups, inhibiting coalescence and breakage. Combined with the bidirectional regulation of slurry viscosity by nanopolymers (reducing stirring viscosity and improving static thixotropy), the bubble distribution is more uniform, and the internal structure is a regular polyhedron. Compared with traditional processes, the aerated concrete blocks have improved freeze-thaw cycle resistance, compressive strength, and reduced shrinkage, resulting in significantly improved overall performance.

[0034] In terms of process optimization, the initial stability of the slurry was improved by adjusting the dry mixing time, the ratio of modified aqueous solution, and the stirring speed; precise temperature control during the static curing and gas generation stage shortened the curing time and prevented cracking; optimized steam parameters during autoclaving accelerated strength development, while natural curing reduced moisture evaporation stress. The overall process increased the daily production capacity of the production line, reduced unit energy consumption, and simultaneously improved production efficiency and economic benefits. Detailed Implementation

[0035] The following detailed embodiments are only used to further illustrate this application and should not be construed as limiting the scope of protection of this application. Those skilled in the art can make some non-essential improvements and adjustments to this application based on the above application content.

[0036] The following is information on domestic suppliers of key related equipment and materials:

[0037] The calcium carbide slag was purchased from Xinjiang Zhongtai Mining and Metallurgy Co., Ltd.

[0038] The fly ash was purchased from the Douhe Power Plant of Datang International Power Generation Co., Ltd.

[0039] The gypsum was purchased from Shandong Taishan Gypsum Co., Ltd.

[0040] The silicate cement was purchased from Anhui Conch Cement Co., Ltd.

[0041] The aluminum powder paste was purchased from the Henan Branch of Aluminum Corporation of China Limited.

[0042] The sodium silicate solution was purchased from Guizhou Hongxing Development Co., Ltd.

[0043] The sodium aluminate solution was purchased from Shandong Haihua Co., Ltd.

[0044] The calcium nitrate solution was purchased from Hubei Xingfa Chemical Group Co., Ltd.

[0045] The zinc sulfate was purchased from Huludao Zinc Industry Co., Ltd.

[0046] The nitrogen gas was purchased from Hangzhou Hangyang Co., Ltd.

[0047] The dimethyl sulfoxide was purchased from Hubei Guangji Pharmaceutical Co., Ltd.

[0048] The 2-(dimethylamino)ethyl methacrylate was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0049] The 2-acrylamide-2-methylpropanesulfonic acid monomer was purchased from Shengli Oilfield Zhongsheng Environmental Protection Co., Ltd.

[0050] The azobisisobutyronitrile was purchased from Tianjin Lianlong New Materials Co., Ltd.

[0051] The icy ether was purchased from Jiangsu Qiangsheng Functional Chemical Co., Ltd.

[0052] The iodomethane was purchased from Zhejiang NHU Co., Ltd.

[0053] The 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride was purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0054] The N-hydroxysuccinimide was purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0055] The ethylenediamine was purchased from Jiangsu Feixiang Chemical Co., Ltd.

[0056] The forced mixer was purchased from China National Building Materials Equipment Group Co., Ltd.

[0057] The mold was purchased from Foshan Keda Manufacturing Co., Ltd.

[0058] The release agent was purchased from Jiangsu Sunrise Chemical Co., Ltd.

[0059] The autoclave was purchased from Dalian Jinzhou Heavy Machinery Group Co., Ltd.

[0060] Example 1

[0061] A carbide slag and fly ash concrete aerated block, the raw material composition of which is as follows: 225g carbide slag, 675g fly ash, 35g gypsum, 55g silicate cement, 1.0g aluminum powder paste, 15g nano-core-shell structured calcium aluminum silicon polymer, and 3g zwitterionic foam stabilizer polymer. The preparation method of the nano-core-shell structured calcium-aluminum-silicon polymer is as follows: First, prepare the reaction raw materials by weighing 50g of fly ash, 500ml of deionized water, 100ml of 1mol / L sodium silicate solution, 50ml of 0.5mol / L sodium aluminate solution, 200ml of 0.2mol / L calcium nitrate solution, and 5g of zinc sulfate. Disperse 50g of fly ash in 500ml of deionized water and stir at 2000rpm for 10 minutes using a high-speed disperser to form a uniform slurry. Slowly add 100ml of sodium silicate solution and 50ml of sodium aluminate solution under continuous high-speed shearing for 15 minutes. Adjust the pH of the slurry to 11.5 with 10% sodium hydroxide solution. Transfer the reaction vessel to a constant temperature water bath and react at 71℃ for 3 hours, maintaining a stirring speed of 30 rpm. 0 rpm; After the reaction is complete, the system temperature is raised to 82℃, and 200 ml of calcium nitrate solution and 5 g of zinc sulfate are slowly added while stirring over 20 minutes; After the addition is complete, the temperature is maintained at 82℃ and the reaction continues for 5 hours, with the stirring speed maintained at 300 rpm during the reaction; After the reaction is complete, the slurry is transferred to a centrifuge and centrifuged at 8000 rpm for 10 minutes, and the supernatant is discarded; The precipitate is washed three times with 200 ml of ethanol, and centrifuged after each wash to terminate the reaction and remove impurities; The washed precipitate is transferred to a vacuum drying oven and vacuum dried at 62℃ for 28 hours; The dried block product is placed in a planetary ball mill and ground at 350 rpm for 2 hours, and then passed through a 450-mesh sieve to obtain a white powdery nano-core-shell structured calcium aluminum silicon polymer product, which is sealed and stored for later use.

[0062] The preparation method of zwitterionic foam stabilizer is as follows: First, prepare the reaction raw materials, weighing 25g of 2-dimethylaminoethyl methacrylate, 25g of 2-acrylamido-2-methylpropanesulfonic acid monomer, 0.5g of azobisisobutyronitrile, 15g of iodomethane, 2g of 1,3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride, 1.2g of N-hydroxysuccinimide, 3g of ethylenediamine, 200ml of dimethyl sulfoxide, and 500ml of deionized water; add 200ml of dimethyl sulfoxide to a 250ml three-necked flask. Methyl sulfoxide was used, and nitrogen gas was bubbled through it for 15 minutes to remove oxygen. 25g of 2-dimethylaminoethyl methacrylate and 25g of 2-acrylamide-2-methylpropanesulfonic acid monomer were added, and the mixture was stirred at 500 rpm until completely dissolved. 0.5g of azobisisobutyronitrile was added, and nitrogen gas was continued to bubble through it. The reaction flask was transferred to a 75°C oil bath, and the reaction was carried out at 300 rpm for 9 hours. After the reaction was complete, the reaction solution was cooled to room temperature and added dropwise to 2000ml of ice-cold diethyl ether with stirring. A white flocculent precipitate formed. Precipitate formed; after standing for 30 minutes, filter and collect the white flocculent precipitate, wash three times with 100 ml of cold ether; dissolve the precipitate in 500 ml of deionized water, add 15 g of iodomethane, transfer the reaction flask to a 41°C water bath, and react at 300 rpm for 13 hours; after the reaction, transfer the reaction solution to a dialysis bag with a molecular weight cutoff of 3500, dialyze in deionized water for 48 hours, changing the water every 6 hours; after obtaining the quaternized linear copolymer solution, add 2 g of 1-3- Dimethylaminopropyl-3-ethylcarbodiimide hydrochloride and 1.2 g of N-hydroxysuccinimide were stirred at 500 rpm for 30 minutes to activate the carboxyl group; 3 g of ethylenediamine was added, and the reaction was carried out at 300 rpm for 12 hours at room temperature; after the reaction was completed, the reaction solution was transferred back into a dialysis bag and dialyzed in deionized water for 72 hours, with the water being changed every 8 hours; finally, the dialyzed solution was freeze-dried for 48 hours to obtain a white solid zwitterionic foam stabilized polymer product, which was sealed and stored for later use.

[0063] The preparation method of aerated concrete blocks includes: First, prepare the raw materials by weighing 225g of calcium carbide slag, 675g of fly ash, 35g of gypsum, 55g of silicate cement, 1.0g of aluminum powder paste, 15g of the prepared nano-core-shell structured calcium aluminum silicon polymer, and 3g of the prepared zwitterionic foam stabilizer polymer; put the calcium carbide slag, fly ash, gypsum, and silicate cement into a forced mixer and dry mix at 400 rpm for 4 minutes until uniform to obtain dry material; dissolve 15g of the nano-core-shell structured calcium aluminum silicon polymer and 3g of the zwitterionic foam stabilizer polymer in 200ml of room temperature deionized water and stir at 800 rpm for 5 minutes using a magnetic stirrer to form a uniform modified aqueous solution; pour the modified aqueous solution into the forced mixer and mix with the dry material at 600 rpm. Stir for 3 minutes to form a uniform slurry; add 1.0g of aluminum powder paste to the slurry and stir at 1200rpm for 38 seconds to disperse it evenly; immediately pour the slurry into a 100mm×100mm×100mm steel mold pre-coated with a release agent, and gently vibrate the mold after pouring to remove large air bubbles; transfer the mold to a 62℃ curing chamber for static curing for 2.5 hours; after the green body hardens, demold it and cut it into standard-sized green bodies using a wire cutter; send the cut green bodies into an autoclave and heat them to 185℃ at a rate of 1.5℃ / min, and cure them under constant pressure at 1.1MPa saturated steam pressure for 9 hours; after curing, reduce the pressure and temperature at a rate of 0.7℃ / min, and allow them to cure naturally at room temperature for 28 days to obtain the finished aerated concrete block.

[0064] Example 2

[0065] The specific implementation method is the same as in Example 1, except that the raw material composition of the carbide slag and fly ash concrete aerated block is as follows: 150g of carbide slag, 600g of fly ash, 20g of gypsum, 80g of silicate cement, 1.5g of aluminum powder paste, 25g of nano-core-shell structured calcium aluminum silicon polymer, and 5g of zwitterionic foam stabilizer polymer. The preparation method of the nano-core-shell structured calcium aluminum silicon polymer is as follows: First, 60g of fly ash is dispersed in 500ml of deionized water to form a uniform slurry. Under high-speed shearing, 120ml of 1mol / L sodium silicate solution and 60ml of 0.5mol / L sodium aluminate solution are added. The pH is adjusted to 12 with sodium hydroxide solution, and the reaction is carried out at 72℃ for 2 hours. Subsequently, under stirring, 250ml of 0.2mol / L calcium nitrate solution and 6g of zinc sulfate are added to the slurry. The reaction temperature is maintained at 84℃ and the reaction is continued for 4 hours. After the reaction is completed, the product is centrifuged, washed three times with ethanol to terminate the reaction, and finally vacuum dried at 64℃ for 24 hours. The product is then ground through a 500-mesh sieve to obtain a white powder product.

[0066] The preparation method of zwitterionic foam stabilizer is as follows: Under nitrogen protection, using 200 ml of dimethyl sulfoxide as solvent, add 30 g of 2-dimethylaminoethyl methacrylate and 20 g of 2-acrylamide-2-methylpropanesulfonic acid monomer; after stirring and dissolving, add 0.6 g of azobisisobutyronitrile, and react in an oil bath at 76℃ for 8 hours to obtain a crude product; add the crude product dropwise to 2000 ml of icy diethyl ether to precipitate, filter and collect the white flocculent precipitate; redissolve the precipitate in 500 ml of deionized water, and add... 18g of iodomethane was added and reacted at 42℃ for 12 hours. After the reaction, the mixture was dialyzed for 48 hours through a dialysis bag with a molecular weight cutoff of 3500 to obtain a quaternized linear copolymer solution. 2.5g of 1-3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride and 1.5g of N-hydroxysuccinimide were added to the solution, and the mixture was stirred and activated for 30 minutes. Then, 4g of ethylenediamine was added, and the mixture was stirred and reacted at room temperature for 12 hours. After the reaction, the mixture was purified again by dialyzing for 72 hours, and finally, the product was freeze-dried to obtain a white solid product. The preparation method of aerated concrete blocks includes: adding carbide slag, fly ash, gypsum, and silicate cement into a forced mixer and dry mixing at 400 rpm for 3 minutes until uniform to obtain dry materials; then, dissolving nano-core-shell structured calcium aluminum silicon polymer and zwitterionic foam stabilizer polymer in 200 ml of water and stirring thoroughly for 5 minutes to form a modified aqueous solution; pouring the modified aqueous solution into a forced mixer and mixing with the dry materials, stirring at 600 rpm for 3 minutes to form a uniform slurry; next, adding aluminum powder paste to the slurry and stirring at 1200 rpm for 30 seconds to disperse it evenly, then pouring the slurry into a mold pre-coated with a release agent and statically curing at 64℃ for 2 hours; after the green body hardens, demolding and cutting to obtain green bodies; sending the cut green bodies into an autoclave and autoclaving at a saturated steam pressure of 1.2 MPa and a temperature of 190℃ for 8 hours; after exiting the autoclave, natural curing for 28 days to obtain the finished product.

[0067] Example 3

[0068] The specific implementation method is the same as in Example 1, except that the raw material composition of the carbide slag and fly ash concrete aerated block is as follows: 300g of carbide slag, 750g of fly ash, 50g of gypsum, 30g of silicate cement, 0.5g of aluminum powder paste, 5g of nano-core-shell structured calcium aluminum silicon polymer, and 1g of zwitterionic foam stabilizer polymer. The preparation method of the nano-core-shell structured calcium aluminum silicon polymer is as follows: First, 40g of fly ash is dispersed in 500ml of deionized water to form a uniform slurry. Under high-speed shearing, 80ml of 1mol / L sodium silicate solution and 40ml of 0.5mol / L sodium aluminate solution are added. The pH is adjusted to 11 with sodium hydroxide solution, and the reaction is carried out at 70℃ for 4 hours. Subsequently, under stirring, 150ml of 0.2mol / L calcium nitrate solution and 4g of zinc sulfate are added to the slurry. The reaction temperature is maintained at 80℃ and the reaction is continued for 6 hours. After the reaction is completed, the product is centrifuged, washed three times with ethanol to terminate the reaction, and finally vacuum dried at 60℃ for 30 hours. The product is then ground through a 400-mesh sieve to obtain a white powder product. The preparation method of zwitterionic foam stabilizer is as follows: Under nitrogen protection, 20g of 2-dimethylaminoethyl methacrylate and 30g of 2-acrylamide-2-methylpropanesulfonic acid monomer were added to 200ml of dimethyl sulfoxide as solvent; after stirring and dissolving, 0.4g of azobisisobutyronitrile was added, and the mixture was reacted in an oil bath at 74℃ for 10 hours to obtain a crude product; the crude product was added dropwise to 2000ml of icy diethyl ether to precipitate the product, and the white flocculent precipitate was collected after filtration; the precipitate was redissolved in 500ml of deionized water, and then... 12g of iodomethane was added and reacted at 40℃ for 14 hours. After the reaction, the mixture was dialyzed for 48 hours through a dialysis bag with a molecular weight cutoff of 3500 to obtain a quaternized linear copolymer solution. 1.5g of 1-3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride and 1.0g of N-hydroxysuccinimide were added to the solution, and the mixture was stirred and activated for 30 minutes. Then, 2g of ethylenediamine was added, and the mixture was stirred and reacted at room temperature for 12 hours. After the reaction, the mixture was purified again by dialyzing for 72 hours, and finally, the product was freeze-dried to obtain a white solid product.The preparation method of aerated concrete blocks includes: adding carbide slag, fly ash, gypsum, and silicate cement into a forced mixer and dry mixing at 400 rpm for 5 minutes until uniform to obtain dry materials; then, dissolving nano-core-shell structured calcium aluminum silicon polymer and zwitterionic foam stabilizer polymer in 200 ml of water and stirring thoroughly for 5 minutes to form a modified aqueous solution; pouring the modified aqueous solution into a forced mixer and mixing it with the dry materials, stirring at 600 rpm for 3 minutes to form a uniform slurry; next, adding aluminum powder paste to the slurry and stirring at 1200 rpm for 45 seconds to disperse it evenly, then pouring the slurry into a mold pre-coated with a release agent and statically curing at 60°C for 3 hours; after the green body hardens, demolding and cutting to obtain green bodies; sending the cut green bodies into an autoclave and autoclaving at a saturated steam pressure of 1.0 MPa and a temperature of 180°C for 10 hours; after exiting the autoclave, natural curing for 28 days to obtain the finished product.

[0069] Comparative Example 1

[0070] The specific implementation method is the same as in Example 1, except that the aerated concrete block made of carbide slag and fly ash has the following raw material composition: 225g carbide slag, 675g fly ash, 35g gypsum, 55g silicate cement, and 1.0g aluminum powder paste. It does not contain nano-core-shell structured calcium aluminum silicon polymer or zwitterionic foam stabilizer polymer. The preparation method of aerated concrete blocks includes: adding carbide slag, fly ash, gypsum, and silicate cement into a forced mixer and dry mixing at 400 rpm for 4 minutes until uniform to obtain dry material; then, adding 200 ml of water to the forced mixer and mixing with the dry material, stirring at 600 rpm for 3 minutes to form a uniform slurry; next, adding aluminum powder paste to the slurry and stirring at 1200 rpm for 38 seconds to disperse it evenly, then pouring the slurry into a mold pre-coated with a release agent and statically curing at 62℃ for 2.5 hours; after the green body hardens, demolding and cutting to obtain green bodies; sending the cut green bodies into an autoclave and autoclaving at a saturated steam pressure of 1.1 MPa and a temperature of 185℃ for 9 hours; after exiting the autoclave, natural curing for 28 days to obtain the finished product.

[0071] Comparative Example 2

[0072] The specific implementation method is the same as in Example 1, except that a carbide slag and fly ash concrete aerated block is provided, with the following raw material composition: 225g carbide slag, 675g fly ash, 35g gypsum, 55g silicate cement, 1.0g aluminum powder paste, and 15g nano-core-shell structured calcium aluminum silicon polymer. No zwitterionic foam stabilizer polymer is added. The preparation method of the nano-core-shell structured calcium aluminum silicon polymer is the same as in Example 1. The preparation method of aerated concrete blocks includes: adding carbide slag, fly ash, gypsum, and silicate cement into a forced mixer and dry mixing at 400 rpm for 4 minutes until uniform to obtain dry material; then, dissolving nano-core-shell structured calcium aluminum silicon polymer in 200 ml of water and stirring thoroughly for 5 minutes to form a modified aqueous solution; pouring the modified aqueous solution into a forced mixer and mixing it with the dry material, stirring at 600 rpm for 3 minutes to form a uniform slurry; next, adding aluminum powder paste to the slurry and stirring at 1200 rpm for 38 seconds to disperse it evenly; pouring the slurry into a mold pre-coated with a release agent and statically curing at 62℃ for 2.5 hours; after the green body hardens, demolding and cutting to obtain the green body; sending the cut green body into an autoclave and autoclaving at a saturated steam pressure of 1.1 MPa and a temperature of 185℃ for 9 hours; after exiting the autoclave, natural curing for 28 days to obtain the finished product.

[0073] Comparative Example 3

[0074] The specific implementation method is the same as in Example 1, except that a carbide slag and fly ash concrete aerated block is provided, with the following raw material composition: 225g carbide slag, 675g fly ash, 35g gypsum, 55g silicate cement, 1.0g aluminum powder paste, and 3g zwitterionic foam stabilizer. No nano-core-shell structured calcium aluminum silicon polymer is added. The preparation method of the zwitterionic foam stabilizer is the same as in Example 1. The preparation method of aerated concrete blocks includes: adding carbide slag, fly ash, gypsum, and silicate cement into a forced mixer and dry mixing at 400 rpm for 4 minutes until uniform to obtain dry material; then, dissolving an amphoteric foam stabilizer polymer in 200 ml of water and stirring thoroughly for 5 minutes to form a modified aqueous solution; pouring the modified aqueous solution into a forced mixer and mixing it with the dry material, stirring at 600 rpm for 3 minutes to form a uniform slurry; next, adding aluminum powder paste to the slurry and stirring at 1200 rpm for 38 seconds to ensure uniform dispersion; pouring the slurry into a mold pre-coated with a release agent and statically curing at 62℃ for 2.5 hours; after the green body hardens, demolding and cutting to obtain the green body; sending the cut green body into an autoclave and autoclaving at a saturated steam pressure of 1.1 MPa and a temperature of 185℃ for 9 hours; and then naturally curing for 28 days after removal from the autoclave to obtain the finished product.

[0075] Performance testing

[0076] The aerated concrete blocks prepared according to Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests according to the following method. All specimens were conditioned to constant weight under a standard environment of 20±2℃ and 50%±5% relative humidity before testing. The dry density test was conducted according to GB / T 11969-2008 "Test Method for Performance of Autoclaved Aerated Concrete". The specimens were placed in a forced-air drying oven and dried at 105±5℃ until the difference between two consecutive weighings did not exceed 0.2% to obtain constant weight. After removal, the specimens were cooled to room temperature in a desiccator, and the mass was weighed using an electronic balance with an accuracy of 0.1g. The dimensions of the specimens were measured with vernier calipers and the volume was calculated to obtain the final dry density value. The compressive strength test was conducted according to GB / T 11971-1997 "Test Methods for Mechanical Properties of Aerated Concrete". A WAW-1000 microcomputer-controlled electro-hydraulic servo universal testing machine was used, with a uniform loading rate of 2.0±0.5 kN / s until specimen failure. The maximum load value was recorded, and the arithmetic mean of six specimens was taken as the calculated compressive strength. Any specimen whose strength value deviated from the average by more than 20% was discarded. The drying shrinkage test was conducted according to GB / T 11972-1997 "Test Methods for Drying Shrinkage of Aerated Concrete". Specimens were placed in a constant temperature and humidity chamber at 20±2℃ and 43%±2% relative humidity. An outside micrometer and a length comparator were used to measure the length change of the specimens at 1, 3, 7, 14, 21, and 28 days. Before measurement, the specimens were removed from the chamber, and the measurement was completed within 2 minutes. The drying shrinkage value was calculated using a formula, and the average of three specimens was taken. Thermal conductivity testing was conducted according to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Insulation Materials - Protective Hot Plate Method". A DPI-03 flat plate thermal conductivity meter was used at an average temperature of 25℃. The specimen surface was required to be flat and smooth, ensuring good contact with the hot plate. During testing, the hot plate temperature was 30℃ and the cold plate temperature was 20℃. Data recording began after the temperature stabilized for 2 hours. Water absorption testing was conducted according to GB / T 11973-1997 "Test Method for Water Absorption of Aerated Concrete". The dry specimen was completely immersed in water at 20±5℃, with the water level 30mm above the specimen surface. After soaking for 24 hours, the specimen was removed, the surface moisture was wiped off with a damp towel, and the specimen was immediately weighed to calculate the water absorption rate. Pore ​​size distribution analysis was performed using mercury porosimetry with an AutoPoreIv 9510 fully automated mercury porosimeter. Approximately 3g of sample was weighed and degassed under vacuum at 100°C for 4 hours, followed by measurements within a pressure range of 0.5–30000 psi. The pore size distribution was calculated using the Washburn equation, with particular attention paid to recording the most probable pore size and the average pore size. For each test item, specimens were prepared and tested strictly according to standard requirements. All data were averaged from at least three valid specimens to ensure the accuracy and reliability of the results.

[0077] Performance test results:

[0078] Table 1: Performance test results of each embodiment and comparative example

[0079]

[0080]

[0081] As shown in Table 1, based on the comparative analysis of test data from the examples and comparative examples, Examples 1-3 of this invention effectively solved the four major technical problems of existing carbide slag and fly ash concrete aerated blocks by synergistically using a nano-core-shell structured calcium aluminum silicon polymer and a zwitterionic foam stabilizer. First, addressing the problem of insufficient cementitious activity of solid waste, the nano-core-shell structured calcium aluminum silicon polymer, as a highly efficient nucleating agent, significantly promoted the pozzolanic reaction between calcium hydroxide in carbide slag and the active components of fly ash, increasing the compressive strength of the example group (5.25-5.82 MPa) by more than 68% compared to Comparative Example 1 (3.12 MPa) without any modifier. Even in Example 3, which used the least amount of cement, it still maintained high strength, proving that it fully activated the cementitious activity of solid waste materials. Secondly, addressing the issue of poor foaming stability, the zwitterionic foam-stabilizing polymer stabilized the gas generation process by forming a high-strength interfacial film, resulting in a uniform and fine pore structure (average pore size 0.32-0.38 μm) in the example group, far superior to the 0.82 μm of Comparative Example 1, with a water absorption rate reduced by approximately 20% and significantly improved independent bubble sealing. Thirdly, addressing the issue of uneven product structure, the synergistic effect of the two modifiers ensured the matching between the hydration reaction and the gas generation process, significantly improving the uniformity of the green body structure. The drying shrinkage value of the example group (0.43-0.51 mm / m) was reduced by approximately 40-50% compared to Comparative Example 1 (0.86 mm / m), avoiding cracking caused by uneven shrinkage. Finally, addressing the issue of low production efficiency, the nano-core-shell polymer accelerated early hydration, allowing the green body to reach cutting strength in a shorter time, shortening the static curing time. Simultaneously, the uniform structure reduced the scrap rate after autoclaving, improving production efficiency. Comparative Examples 2 and 3, which added only a single modifier, showed better performance than Comparative Example 1 but significantly lower performance than the Example Group. This fully demonstrates that the two modifiers have an indispensable synergistic effect in optimizing the hydration process and stabilizing the bubble structure, thereby improving the mechanical properties, durability, and production reliability of the aerated concrete block products as a whole.

[0082] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An aerated concrete block made of carbide slag and fly ash, characterized in that, Including the following parts by weight of raw materials: Calcium carbide slag: 150-300 parts by weight; Fly ash: 600-750 parts by weight; Gypsum: 20-50 parts by weight; Silicate cement: 30-80 parts by weight; Aluminum powder paste: 0.5-1.5 parts by weight; Nanocore-shell structured calcium aluminum silicon polymer: 5-25 parts by weight; Amphoteric foam stabilizer: 1-5 parts by weight; The preparation method of the nano-core-shell structured calcium aluminum silicon polymer includes: A1, dispersing fly ash in deionized water to form a uniform slurry, adding sodium silicate solution and sodium aluminate solution under high-speed shear, adjusting the pH to 11-12, and reacting at 70-72℃; A2, subsequently adding calcium nitrate solution and zinc sulfate to the slurry, maintaining the reaction temperature at 80-84℃, and continuing the reaction; after the reaction is completed, centrifuging and washing with ethanol to terminate the reaction, and finally vacuum drying at 60-64℃, grinding and sieving. The preparation method of the zwitterionic foam stabilizer includes: B1, under nitrogen protection, using dimethyl sulfoxide as solvent, adding 2-(dimethylamino)ethyl methacrylate and 2-acrylamide-2-methylpropanesulfonic acid monomers; after stirring and dissolving, adding azobisisobutyronitrile, and reacting in an oil bath at 74-76℃ to obtain a crude product; B2, adding the crude product dropwise to refractory ether for precipitation, filtering and collecting the white flocculent precipitate; redissolving the precipitate in deionized water, adding iodomethane, and reacting at 40-42℃; after the reaction, dialyzing through a dialysis bag to obtain a quaternized linear copolymer solution; adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide to the quaternized linear copolymer solution, then adding ethylenediamine, and stirring at room temperature; after the reaction, dialysis purification again, and finally freeze-drying.

2. The aerated concrete block made of carbide slag and fly ash according to claim 1, characterized in that, In step A1, the reaction time is 2-4 hours at 70-72℃.

3. The aerated concrete block made of carbide slag and fly ash according to claim 1, characterized in that, In step A2, the reaction time is 4-6 hours; the vacuum drying time at 60-64℃ is 24-30 hours; and the material is ground through a 400-500 mesh sieve.

4. The aerated concrete block made of carbide slag and fly ash according to claim 1, characterized in that, In step B1, the reaction time in an oil bath at 74-76℃ is 8-10 hours.

5. The aerated concrete block made of carbide slag and fly ash according to claim 1, characterized in that, In step B2, the reaction time is 12-14 hours at 40-42℃.

6. A method for preparing aerated concrete blocks made of carbide slag and fly ash according to any one of claims 1-5, characterized in that, step include: S1. Add carbide slag, fly ash, gypsum and silicate cement into a forced mixer and dry mix until uniform to obtain dry material; Subsequently, the nano-core-shell structured calcium aluminum silicon polymer and the zwitterionic foam stabilizer polymer were dissolved in water and stirred thoroughly to form a modified aqueous solution; S2. Pour the modified aqueous solution into a forced mixer and mix it with the dry materials to form a uniform slurry. Then, add aluminum powder paste to the slurry and stir at high speed to disperse it evenly. Pour the slurry into a mold pre-coated with a release agent and cure it at 60-64℃. After the green body hardens, demold it and cut it to obtain the green body. S3. The cut blanks are sent into an autoclave and autoclaved under conditions of saturated steam pressure of 1.0-1.2MPa and temperature of 180-190℃; after exiting the autoclave, they are naturally cured.

7. The preparation method according to claim 6, characterized in that, In step S1, the dry mixing time is 3-5 minutes.

8. The preparation method according to claim 6, characterized in that, In step S2, the high-speed stirring time is 30-45 seconds; the static curing time at 60-64℃ is 2-3 hours.

9. The preparation method according to claim 6, characterized in that, In step S3, the autoclaving time is 8-10 hours.

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