Autoclaved aerated concrete product and preparation method thereof

Abstract

The invention relates to the technical field of building materials, and discloses an autoclaved aerated concrete product, which is prepared from the following ingredients in percentage by mass: 80 to 84 percent of slurry, 8 to 12 percent of cement, 4 to 12 percent of carbide slag, 0.06 to 0.09 percent of water reducing agents and 0.06 to 0.12 percent of foaming agents. The mass ratio of the water to the total amount of the materials is 0.53-0.55; the preparation method comprises the following steps: S1, preparing slurry and pretreating the carbide slag; s2, stirring and mixing: uniformly mixing the slurry prepared in the step S1, cement, the carbide slag pretreated in the step S1, a foaming agent and a water reducing agent according to a certain mass ratio to prepare a mixed material, then adding water into the mixed material, and uniformly stirring to form mixed slurry; s3, pouring and standing maintenance are carried out; s4, cutting is conducted; s5, pressurized steam curing; s6, demolding, trimming and curing are conducted, and finally the autoclaved aerated concrete product is obtained. According to the scheme, the replacement proportion of the carbide slag can be increased, and the problems of high cost, unstable quality and environmental pollution of a traditional process are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and particularly relates to an autoclaved aerated concrete product and a preparation method thereof. Background Art

[0002] Under the background of the booming development of the construction industry, the market's demand for high-performance and environmentally friendly building materials is increasing day by day. Autoclaved aerated concrete has been increasingly widely used in the construction field due to its outstanding advantages such as light weight, heat insulation, and sound insulation. In the production process of autoclaved aerated concrete, calcareous materials, as key raw materials, directly determine the quality of the products and the level of production costs.

[0003] For a long time, the cement-lime composite calcareous material system has dominated the production of autoclaved aerated concrete. In this system, cement plays a role in endowing the products with early strength, enabling the hydration reaction to proceed in an orderly manner, and can also flexibly control the setting time. Quicklime, as the main calcium source, not only provides free calcium oxide, but the heat and water absorption released during its slaking process create an alkaline environment that greatly accelerates the matrix reaction. The addition of gypsum stabilizes the product volume and reduces the cracking risk by adjusting the slaking time of quicklime.

[0004] However, with the development of the industry, the disadvantages of this traditional process have become increasingly obvious. The price of quicklime is high and the market fluctuates frequently, making it difficult to control production costs. At the same time, parameters such as the activity and impurity content of quicklime are unstable, resulting in large fluctuations in product quality, difficulty in ensuring batch-to-batch consistency, and relatively slow development of the product's later strength. In addition, a large amount of dust and waste gas are generated during the production of quicklime, seriously polluting the environment, which is contrary to the current development concept of green environmental protection.

[0005] At the same time, China's wet process for producing acetylene from calcium carbide has been around for more than 60 years, and a large amount of carbide slag, as a by-product, has been piling up. The main component of carbide slag is calcium hydroxide, which has mostly been discarded for a long time, not only causing a great waste of resources but also seriously polluting the environment.

[0006] To solve the above problems, some domestic research institutions and production enterprises have begun to try to use carbide slag to replace quicklime in the production of autoclaved aerated concrete. However, at present, the replacement ratio of carbide slag in the production process is generally low, with a maximum of no more than 40%, and there are still great challenges in cost control and solid waste disposal, and the progress is very slow. Summary of the Invention

[0007] The present invention aims to provide an autoclaved aerated concrete product and its preparation method, so as to increase the substitution ratio of carbide slag in the production of autoclaved aerated concrete, effectively solve the problems of high cost, unstable product quality and environmental pollution in the traditional cement-lime process, achieve efficient solid waste disposal, and reduce production costs.

[0008] To achieve the above object, the present invention adopts the following technical solution: An autoclaved aerated concrete product, comprising materials in the following mass percentages: 80-84% of slurry, 8-12% of cement, 4-12% of carbide slag, 0.06-0.09% of water reducing agent, 0.06-0.12% of foaming agent; the mass ratio of water to the total amount of materials is 0.53-0.55.

[0009] Preferably, the slurry comprises sand, waste slurry and coal ash, and their mass ratios are (6-7):(1.5-2):1 in sequence, and the waste slurry is the recycled slurry generated from the cutting of production line scraps.

[0010] Preferably, the cement is any one or a combination of several of portland cement, ordinary portland cement, slag portland cement, coal ash portland cement, pozzolanic portland cement and composite portland cement.

[0011] Preferably, the foaming agent is aluminum paste.

[0012] The present invention also provides another technical solution, a preparation method of an autoclaved aerated concrete product, comprising the following steps:

[0013] S1: Prepare the slurry and pretreat the carbide slag;

[0014] S2: Stir and mix: Mix the slurry, cement, carbide slag pretreated in S1, foaming agent and water reducing agent prepared in S1 evenly according to a certain mass ratio to form a mixed material, and then add water to the mixed material and stir evenly to form a mixed slurry;

[0015] S3: Pouring and static curing: Pour the mixed slurry prepared in S2 into a mold, control the pouring temperature at 55-60 °C, and then carry out static curing;

[0016] S4: Cutting: After the concrete begins to set, turn over the mold and cut the blank;

[0017] S5: Pressurized steam curing: Transfer the cut concrete blocks in S4 to an autoclave for autoclave curing;

[0018] S6: Demolding, trimming and curing: Demold after autoclave curing is completed, trim and cure the product, and finally obtain an autoclaved aerated concrete product.

[0019] Preferably, the pretreatment of the carbide slag includes the following steps:

[0020] Step 1, drying: Dry by natural precipitation or drying, and control the moisture content of carbide slag below 3%.

[0021] Step 2, grinding: Grind the dried carbide slag in Step 1.

[0022] Preferably, if the drying method is used to dry the carbide slag, the drying temperature is 150 - 200 °C.

[0023] Preferably, in S2, stir for 3 - 5 min after adding water.

[0024] Preferably, in S3, the static curing is divided into a static stage and a pre-curing stage. In the static stage, maintain the ambient temperature at 40 - 60 °C, control the humidity at 70 - 95%, and the curing duration is 1.5 - 5 h; in the pre-curing stage, put the concrete block after static curing into the pre-curing kiln, ensure that the kiln body is in a closed state, use saturated steam to form a circulating air flow, and cure at 80 - 100 °C.

[0025] Preferably, in S5, the autoclave curing uses AAC autoclave curing or ALC autoclave curing.

[0026] Compared with the prior art, this solution has made major breakthroughs in multiple dimensions such as cost reduction and efficiency improvement, quality improvement, and environmental protection. The specific beneficial effects are as follows:

[0027] (1) Build a production model with low cost and high resource utilization rate

[0028] Deeply reduce raw material costs: Innovatively achieve 100% replacement of quicklime with carbide slag and abandon the use of gypsum. As an industrial waste, carbide slag is cheap and widely sourced. This measure not only completely gets rid of the cost troubles brought by the high price and volatility of quicklime, but also greatly reduces the raw material procurement expenses, fundamentally reshaping the cost structure of autoclaved aerated concrete.

[0029] Breakthrough reduction in energy consumption: Break the dependence on traditional processes, cancel the quicklime production link, and effectively avoid a large amount of energy consumption and carbon dioxide emissions during this process. After calculation, compared with the traditional process, the production energy consumption of this solution is significantly reduced, greatly reducing the production cost, providing a new path for improving the resource and energy utilization efficiency, and conforming to the green development trend.

[0030] Lead a new paradigm of resource recycling: Convert the long-term abandoned carbide slag into a key raw material for autoclaved aerated concrete, greatly improving the resource recycling rate. This transformation reduces the dependence on natural calcareous resources and avoids resource waste, meeting the requirements of the sustainable development strategy and setting a benchmark for the efficient utilization of resources in the industry.

[0031] (2) Create a product system with stable quality and excellent performance

[0032] Significantly improve early strength: By scientifically increasing the cement content, a solid foundation is laid for the early strength of the product. At the same time, the aluminum powder content is accurately increased to enhance the gas generation efficiency and promote the formation of a uniform and stable pore structure at an early stage. In addition, the pouring temperature is strictly controlled to accelerate the cement hydration reaction. According to tests, the early strength of the products produced by this solution is significantly improved compared with the traditional process.

[0033] Achieve precise and controllable product performance: Carbide slag has a stable composition, which provides reliable guarantee for product quality control compared with quicklime whose activity and impurity content fluctuate greatly. Through precise process parameter control, quality differences caused by raw material fluctuations can be effectively eliminated, ensuring that the performance of each batch of products is highly consistent and meets high standards of building quality requirements.

[0034] Efficiently compensate for performance loss: In response to the possible performance loss after the abolition of quicklime and gypsum, this solution innovatively adopts the method of reducing the water-to-cement ratio in combination with the use of a water reducer to accurately control the fluidity of concrete and greatly promote the cement hydration reaction. After eliminating gypsum, the process parameters are cleverly optimized to actively promote the setting time, compensate for the early strength loss, and ensure the comprehensive performance of the product. In the production of traditional autoclaved aerated concrete products, gypsum is mainly used to adjust the dissolution time of quicklime. However, this technology has completely eliminated the use of quicklime, and gypsum has lost its main function. On the contrary, as a retarder for cement, gypsum's retarding effect will inhibit the strength of the static stage after addition, resulting in a negative impact.

[0035] (3) Create a new low-pollution, sustainable environmental protection situation

[0036] Significantly reduce pollutant emissions: Completely eliminate the quicklime production process, directly eliminate the generation of a large amount of dust and waste gas in the process, and curb environmental pollution from the source. At the same time, the reuse of carbide slag reduces the accumulation of industrial waste, reduces the risk of pollution to soil, water sources, etc., significantly improves the quality of the ecological environment, and makes a positive contribution to environmental protection.

[0037] (4) Promote revolutionary changes in material systems and industries

[0038] Innovative resource utilization of carbide slag: Using carbide slag as the main calcium material and exploring a new path for resource utilization of industrial waste not only conforms to the concept of circular economy, but also provides a reference example for the reuse of other industrial wastes, and promotes the sustainable utilization of resources to a new level.

[0039] Leading the upgrading of the autoclaved aerated concrete industry: comprehensively replacing the traditional cement-lime calcareous materials with cement-electric slag composite calcareous materials, achieving 100% replacement of quicklime. This innovation in the material system has triggered systematic changes from raw material procurement, production processes to product quality, injecting a powerful innovation driving force into the sustainable development of the autoclaved aerated concrete industry. Detailed implementation methods

[0040] The following is a further detailed description through specific implementation methods:

[0041] Example 1

[0042] An autoclaved aerated concrete product, including materials with the following mass percentages: 80-84% slurry, 8-12% cement, 4-12% electric slag, 0.06-0.09% water reducer, 0.06-0.12% foaming agent; the mass ratio of water to the total amount of materials is 0.53-0.55. In this implementation, the dosage of various materials and the mass ratio of water to the total amount of materials are shown in Table 3.

[0043] The slurry includes sand, waste slurry and coal ash, and their mass ratios are (6-7):(1.5-2):1 in sequence. The waste slurry is the recycled slurry generated from the cutting of production line scraps. In this example, the mass ratios of sand, waste slurry and coal ash are 7:2:1 in sequence.

[0044] The cement is any one or a combination of several of portland cement, ordinary portland cement, slag portland cement, coal ash portland cement, pozzolanic portland cement and composite portland cement. In this implementation, 42.5-grade ordinary portland cement is selected as the cement.

[0045] The calcium content of the electric slag used reaches 67.35%.

[0046] The water reducer adopts the super-dispersed, high anti-sludge, high foam stability, low shrinkage, enhanced liquid regulator for autoclaved aerated concrete prepared according to the technical solution of Example 1 with the patent number CN113860834B.

[0047] The foaming agent is aluminum paste.

[0048] A preparation method of an autoclaved aerated concrete product includes the following steps:

[0049] S1: Prepare the slurry and pre-treat the electric slag;

[0050] The preparation process of the slurry is as follows: Weigh sand, waste slurry and coal ash according to the mass ratio of 7:2:1, put them into a ball mill for ball milling and mixing until the residue rate of the ball-milled material reaches 20% when passing through a 200-mesh sieve.

[0051] The pre-treatment of the electric slag includes the following steps:

[0052] Step 1, drying: The carbide slag is dried by natural precipitation or drying, and the moisture content of the carbide slag is controlled below 3%; if drying is used, a drum dryer is used for drying operation, and the drying temperature is controlled at 150 - 200 °C; in this embodiment, drying is used, and the drying temperature is 160 °C;

[0053] Step 2, grinding: The dried carbide slag in Step 1 is ground so that when the ground carbide slag passes through a 200 - mesh sieve, the residue rate is controlled at 8 - 15%. A residue rate lower than 8% will double the water demand and affect the quality, and will increase the wear cost. A residue rate higher than 15% will affect its effective reaction activity and is prone to quality problems such as "explosion points".

[0054] S2: Stirring and mixing

[0055] The slurry prepared in S1, cement, the carbide slag pretreated by S1, foaming agent and water - reducing agent are mixed evenly according to a certain mass ratio to form a mixed material. Subsequently, water is added to the mixed material and stirred continuously for 3 - 5 min to form a mixed slurry; in this embodiment, the mass ratio of the slurry, cement, the carbide slag pretreated by S1, foaming agent and water - reducing agent is 3470:360:280:1.8:2.67. After adding water, the stirring duration is 4 min, and the mass ratio of water to the mixed material is 0.53.

[0056] The slurry prepared in S1, cement, the carbide slag pretreated by S1, water - reducing agent, foaming agent are put into a forced - type mixer and mixed evenly according to a mass ratio of 3470:360:280:1.8:2.67 to form a mixed material. Subsequently, water is added to the mixed material and stirred continuously for 3 - 5 min to form a mixed slurry, where the mass ratio of water to the mixed material is 0.53 - 0.54; in this example, after adding water, the stirring duration is accurately controlled at 4 min, and the mass ratio of water to the mixed material is 0.532.

[0057] S3: Pouring and static curing

[0058] Inject the mixed slurry prepared in S2 into the mold, control the casting temperature at 55 - 60°C, and then carry out static curing. The static curing is divided into a static stage and a pre-curing stage. In the static stage, maintain the ambient temperature at 40 - 60°C, control the humidity at 70 - 95%, and the curing duration is 1.5 - 5 h; in the pre-curing stage, put the concrete block after static curing into the pre-curing kiln, ensure that the kiln body is in a closed state, use saturated steam to form a circulating air flow, and cure at 80 - 100°C; in this embodiment, the casting temperature is controlled at 58.7°C, and the casting spread is 200; in the static stage, maintain the ambient temperature at 50°C, control the humidity at 80%, and the curing duration is 5 h; in the pre-curing stage, ensure that the kiln body is in a closed state, use saturated steam to form a circulating air flow, and cure at 90°C; the main function of the pre-curing stage is to carry out curing work on the embryo during the waiting period for the embryo to enter the autoclave, and prevent the embryo from being damaged in quality due to water evaporation, temperature reduction, and carbonization. The pre-curing duration can be determined according to the actual production situation.

[0059] S4: Cutting

[0060] After the concrete begins to set, flip the mold to cut the green body.

[0061] S5: Pressurized steam curing. Transfer the cut concrete block in S4 to the autoclave for autoclave curing. The pressurized steam curing adopts AAC autoclave curing or ALC autoclave curing; in this embodiment, AAC autoclave curing is adopted.

[0062] The process of AAC autoclave curing is as follows:

[0063] Vacuum pumping: After vacuum pumping, the vacuum degree in the autoclave is -0.06~-0.07 MPa. In this embodiment, the vacuum degree in the autoclave after vacuum pumping is -0.06 MPa.

[0064] The temperature rise is divided into multiple stages. Different autoclave pressure ranges correspond to different temperature rise speeds and times, as shown in Table 1 specifically:

[0065] Table 1

[0066]

[0067] When the temperature in the autoclave reaches 100 - 120°C, the temperature rise speed shall not be greater than 30 s / 0.01 bar, and the temperature rise speed shall not be faster than 1.5 min / °C.

[0068] Constant temperature: When the gauge pressure in the autoclave rises to 1.2 MPa and the temperature gauge reaches 190°C, the gas distribution station closes to stop the temperature rise. The constant temperature pressure is maintained at 1.0 - 1.2 MPa, and the constant temperature time is 8 h. When the pressure in the autoclave is lower than 1 MPa or the temperature is lower than 180°C, drain the water first and then supplement the steam to 1.2 MPa.

[0069] Cooling: The cooling rate should not be too fast. The cooling time from 0.3 MPa to atmospheric pressure should be ≥ 1 h.

[0070] Autoclave curing process of ALC:

[0071] Preparations before entering the autoclave:

[0072] Insulation and moisture retention measures should be taken in the pre-autoclave insulation chamber to avoid excessive loss of the temperature and moisture of the embryo body.

[0073] Check and record the temperature when the embryo body enters the autoclave for adjusting the air inlet time.

[0074] Preheat the green body and the autoclave during winter production.

[0075] Vacuum pumping: After vacuum pumping, the vacuum degree in the autoclave is -0.06 to -0.07 MPa. In this embodiment, the vacuum degree in the autoclave after vacuum pumping is -0.06 MPa.

[0076] The temperature increase is divided into multiple stages. Different autoclave pressure ranges correspond to different temperature increase speeds and times, as shown in Table 2 specifically:

[0077] Table 2

[0078]

[0079] Constant temperature and drainage: The constant temperature pressure is 12 bar, the constant temperature is ≥ 190 °C, and the constant temperature time is 10 h. Manually drain water before and after the autoclave once per hour after constant temperature. The drainage time is not less than 20 s. After drainage, make up steam to the constant pressure.

[0080] Gas guiding, cooling and discharging from the autoclave: The gas guiding and cooling speeds should not be too fast. The cooling time from 3 bar to atmospheric pressure should be ≥ 2 h; In winter, after opening the autoclave door, wait for 20 - 30 min before discharging from the autoclave and avoid direct blowing of cold air.

[0081] S6: Demolding, trimming and curing

[0082] After autoclave curing is completed, take out the mold, remove the concrete block from the mold, conduct an appearance inspection on the demolded concrete product, trim the parts with problems such as corner defects and uneven surfaces. After trimming, place the product in the natural environment for curing for 3 days to allow its strength to continue to increase. Finally, obtain autoclaved aerated concrete products that meet the quality requirements, and conduct stacking and packaging. The test results are shown in Table 4.

[0083] Comparative Example 1

[0084] Different from Example 1, an autoclaved aerated concrete product does not include water reducing agent and carbide slag, and also includes waste slurry, lime and gypsum. The usage amounts of various materials and the mass ratio of water to the total amount of materials are shown in Table 3. The waste slurry is the recycled slurry generated from the cutting of production line scraps.

[0085] A preparation method of autoclaved aerated concrete products. In S1, there is a pretreatment process without carbide slag. In S2, the slurry prepared in S1, waste slurry, lime, gypsum, cement and foaming agent are mixed evenly according to a fixed mass ratio of 3280:400:190:126:330:2.47 to form a mixed material. Subsequently, water is added to the mixed material and stirred continuously for 4 min to form a mixed slurry, and the mass ratio of water to the mixed material is 0.588. In S3, the casting temperature is controlled at 56.2 °C and the casting spread is 220. Other steps are the same as those in Example 1. The test results are shown in Table 4.

[0086] Comparative Example 2

[0087] Different from Example 1, an autoclaved aerated concrete product further includes external added water, lime and gypsum. The dosages of various materials and the mass ratio of water to the total amount of materials are shown in Table 3.

[0088] A preparation method of autoclaved aerated concrete products. In S2, the slurry prepared in S1, external added water, lime, gypsum, cement, carbide slag pretreated in S1, foaming agent and water reducing agent are mixed evenly according to a fixed mass ratio of 3440:30:100:121.6:360:120:2.6:1.8 to form a mixed material. Subsequently, water is added to the mixed material and stirred continuously for 4 min to form a mixed slurry, and the mass ratio of water to the mixed material is 0.532. In S3, the casting temperature is controlled at 56.3 °C and the casting spread is 205. Other steps are the same as those in Example 1. The test results are shown in Table 4.

[0089] Comparative Example 3

[0090] Different from Example 1, an autoclaved aerated concrete product does not include carbide slag and water reducing agent, and further includes waste slurry, lime and gypsum. The dosages of various materials and the mass ratio of water to the total amount of materials are shown in Table 3. The waste slurry is the recycled slurry generated from the cutting of production line scraps.

[0091] A preparation method of autoclaved aerated concrete products. In S1, there is a pretreatment process without carbide slag. In S2, the slurry prepared in S1, waste slurry, lime, gypsum, cement and foaming agent are mixed evenly according to a fixed mass ratio of 3180:500:210:126:310:2.47 to form a mixed material. Subsequently, water is added to the mixed material and stirred continuously for 4 min to form a mixed slurry, and the mass ratio of water to the mixed material is 0.578. In S3, the casting temperature is controlled at 55.8 °C and the casting spread is 200. Other steps are the same as those in Example 1. The test results are shown in Table 4.

[0092] Table 3

[0093]

[0094]

[0095] Table 4

[0096]

[0097] Conclusion: When comparing Example 1 with Comparative Example 1, it was found that their performances in the cutting, stacking, and packing processes were the same, and no abnormal situations occurred. However, there were significant differences in terms of performance indicators and costs. The performance indicators of Example 1 were excellent. The autoclave strength reached 3.1 Mpa, the absolute dry bulk density was 620 kg / m 3 , the absolute dry strength was 4.0 Mpa, fully meeting the quality requirements of B06.A3.5 in GB / T11968-2020. In contrast, for Comparative Example 1, its absolute dry strength was only 3.3 Mpa. The absolute dry strength of Example 1 was 0.7 Mpa higher than that of Comparative Example 1, which fully indicates that Example 1 is significantly superior to Comparative Example 1 in terms of product quality. In addition, in terms of cost control, Example 1 demonstrated outstanding advantages. Its material cost was reduced by 14.4 yuan / m compared with Comparative Example 1 3 . This means that the material formula and preparation process adopted in Example 1 can not only ensure product quality but also effectively reduce production costs, having high application value and economic benefits.

[0098] Looking at Comparative Example 2 and Comparative Example 3 again, no abnormalities occurred in their cutting, stacking, and packing effects, and their performances were the same. The autoclave strength of Comparative Example 2 was 3.1 Mpa, the absolute dry bulk density was 624 kg / m 3 , the absolute dry strength was 4.4 Mpa, and all indicators met the quality requirements of B06.A3.5 in GB / T11968-2020. Compared with Comparative Example 1, the absolute dry strength of Comparative Example 2 was 0.5 Mpa higher, with better quality, and at the same time, the material cost was reduced by 3.92 yuan / m compared with Comparative Example 1 3 .

[0099] Based on the above comparison results, it can be seen that in the comparison between Example 1 and Comparative Example 1, Example 1 not only stood out in terms of quality with a higher absolute dry strength but also achieved significant optimization in cost control. The material cost per cubic meter was reduced by 14.4 yuan. For large-scale production, this can greatly increase the profit margin of the enterprise and enhance the price competitiveness of the product in the market.

[0100] The comparison between Comparative Example 2 and Comparative Example 3 also provides us with valuable reference. Comparative Example 2 meets the quality requirements of B06.A3.5 in GB / T11968-2020 in terms of various performance indicators, and its absolute dry strength is 0.5 Mpa higher than that of Comparative Example 1, and the material cost is also reduced.

[0101] Overall, the material formula and preparation process adopted in Example 1 have the most prominent advantages. It not only meets high-quality standards but also performs excellently in cost control, with extremely high promotion value.

[0102] The above are only the embodiments of the present invention. Specific technical solutions and / or common knowledge such as characteristics well known in the art are not described in detail herein. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicality of the patent. The protection scope required by this application shall be subject to the content of its claims, and the specific implementation manners described in the specification can be used to interpret the content of the claims.

Claims

1. An autoclaved aerated concrete product, characterized in that: It includes materials with the following mass percentages: 80 - 84% of slurry, 8 - 12% of cement, 4 - 12% of carbide slag, 0.06 - 0.09% of water reducing agent, and 0.06 - 0.12% of foaming agent; the mass ratio of water to the total amount of materials is 0.53 - 0.

55.

2. An autoclaved aerated concrete product according to claim 1, characterized in that: The slurry includes sand, waste slurry, and coal ash, and their mass ratio is (6 - 7):(1.5 - 2):1 in sequence. The waste slurry is the recycled slurry generated from the cutting of production line scraps.

3. The autoclaved aerated concrete product according to claim 2, wherein: The cement is any one or a combination of several of portland cement, ordinary portland cement, slag portland cement, coal ash portland cement, pozzolanic portland cement, and composite portland cement.

4. The autoclaved aerated concrete product according to claim 3, characterized in that: The foaming agent is aluminum paste.

5. A preparation method of autoclaved aerated concrete products, characterized in that: It includes the following steps: S1: Prepare the slurry and pre - treat the carbide slag. S2: Stir and mix: Mix the slurry, cement, carbide slag pretreated in S1, foaming agent, and water reducing agent prepared in S1 evenly according to a certain mass ratio to make a mixed material. Then add water to the mixed material and stir evenly to form a mixed slurry. S3: Casting and initial setting curing: Pour the mixed slurry prepared in S2 into a mold, control the casting temperature at 55 - 60 °C, and then carry out initial setting curing. S4: Cutting: After the concrete begins to set, turn over the mold to cut the green body. S5: Pressurized steam curing: Transfer the cut concrete blocks in S4 to an autoclave for autoclave curing. S6: Demolding, trimming, and curing: Demold after autoclave curing is completed, trim and cure the concrete blocks to finally obtain autoclaved aerated concrete products.

6. The preparation method of an autoclaved aerated concrete product according to claim 5, characterized in that: In S1, the pre - treatment of carbide slag includes the following steps: The first step, drying: Dry it by natural precipitation or drying, and control the moisture content of the carbide slag below 3%. The second step, grinding: Grind the dried carbide slag in the first step.

7. The preparation method of an autoclaved aerated concrete product according to claim 6, characterized in that: If the drying method is used to dry the carbide slag, the drying temperature is 150 - 200 °C.

8. The preparation method of an autoclaved aerated concrete product according to claim 7, characterized in that: In S2, stir for 3 - 5 min after adding water.

9. The preparation method of an autoclaved aerated concrete product according to claim 8, characterized in that: In S3, the initial setting curing is divided into an initial setting stage and a pre - curing stage. In the initial setting stage, maintain the ambient temperature at 40 - 60 °C, control the humidity at 70 - 95%, and the curing duration is 1.5 - 5 h; in the pre - curing stage, put the concrete blocks after initial setting curing into a pre - curing kiln, ensure that the kiln body is in a closed state, use saturated steam to form a circulating air flow, and cure at 80 - 100 °C.

10. The preparation method of an autoclaved aerated concrete product according to claim 9, characterized in that: In S5, the pressurized steam curing adopts AAC autoclave curing or ALC autoclave curing.

Images