Aerated concrete prepared by using granite waste rock powder and a preparation method thereof

Abstract

The application relates to an aerated concrete prepared from granite waste rock powder and a preparation method thereof. The aerated concrete of the application takes granite waste rock powder (skeleton effect), calcium carbide slag (calcic material), clay (sintering promotion), red mud (gel filling) and coal gangue (siliceous material) as core raw materials, replaces traditional natural sandstone and lime, realizes industrial solid waste resource utilization, conforms to the development direction of green building materials, and significantly reduces the dependence on natural resources.

Description

Technical Field

[0001] This invention relates to the technical field of aerated concrete, specifically to an aerated concrete prepared using granite waste powder and its preparation method. Background Technology

[0002] Currently, the stone processing industry in Fujian, Guangdong, and other regions is experiencing rapid growth. However, the stone processing process generates a large amount of waste, such as granite waste powder, which poses a serious threat to the local ecological environment. Granite waste powder is essentially composed of fine particles of silicate minerals (such as quartz, feldspar, and amphibole). If granite waste powder could be applied to ultra-high performance concrete to partially replace cementitious materials (such as cement and silica fume), it is expected to bring significant economic and environmental benefits.

[0003] However, granite waste powder presents a significant challenge: it is highly susceptible to clumping due to moisture. In practical applications, specific pretreatment is typically required, which not only increases disposal costs but may also lead to secondary pollution. Furthermore, from a thermodynamic perspective, when wet granite waste powder solid particles are dispersed, the free energy of the dispersion system increases, causing instability and a tendency for the dispersed particles to agglomerate, ultimately forming lumps of wet granite waste powder. This situation is detrimental to the uniform mixing of concrete. Therefore, in-depth research into the application methods of wet granite waste powder in concrete and optimization of the preparation process of ultra-high performance concrete have significant research value and application prospects. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an aerated concrete prepared using granite waste powder and its preparation method.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for preparing aerated concrete using granite waste powder, comprising the following steps:

[0007] S1. First, mix granite waste stone powder and clay, then add coal gangue, carbide slag and red mud, heat to 1050-1250℃ and keep warm to obtain calcined material; the mass ratio of granite waste stone powder, clay, coal gangue, carbide slag and red mud is (20-30):(0.5-1):(2-5):(5-15):1;

[0008] S2. The calcined material is cooled, then mixed with saline-alkaline wastewater, and ball-milled to obtain the granite-based slurry; wherein the pH of the saline-alkaline wastewater is 11-13, and the solid content of the granite-based slurry is 60-70 wt%.

[0009] S3. Mix granite-based slurry, cement, gypsum, and water-reducing agent, then add foaming agent and mix again to obtain a mixed slurry; wherein the mass ratio of granite-based slurry, cement, gypsum, water-reducing agent, and foaming agent is 100:(5-10):(1-5):(1-3):(1-3);

[0010] S4. Inject the mixed slurry into the mold, let it stand, demold and divide it, and steam cure it to obtain the aerated concrete.

[0011] This invention systematically solves the problem of dispersing granite waste powder in concrete systems through innovative raw material ratios and process design, and realizes the high-value utilization of industrial solid waste. The roles of each raw material are as follows:

[0012] Granite waste stone powder (skeleton support + silicon-aluminum source): Granite waste stone powder is mainly composed of quartz, feldspar, and mica, with clay as the main binder, which can combine materials such as feldspar and quartz. Quartz has a high melting point and acts as a skeleton during sintering, reducing drying and shrinkage caused by sintering and enhancing the wear resistance, strength, and chemical stability of the body and glaze. Feldspar has melting properties, which facilitates the sintering of the body. The granite waste stone powder of this invention and clay can form ceramics at a calcination temperature of 1050-1250℃. The ceramic surface is hard, and the interior has a dense honeycomb-like micropore structure, which to a certain extent restricts its expansion behavior. Aerated concrete also contains a large number of pores, which also affect its expansion behavior. The similar porous structure of both makes their coefficients of linear expansion similar when the temperature changes, which can effectively reduce cracks and deformations caused by temperature changes. This can also improve the compatibility of granite waste stone powder in the aerated concrete system, making the prepared aerated concrete less prone to cracking and deformation. Meanwhile, the rigid framework formed by ceramics after calcination of granite waste powder also increases the strength of aerated concrete.

[0013] Calcium carbide slag (CaO source): The chemical composition of calcium carbide slag is mainly Ca(OH)2, which produces CaO upon calcination and water loss. This differs from traditional lime production through limestone burning. Furthermore, the calcium carbide slag in this invention has a low dehydration temperature and does not emit CO, resulting in CaO with higher activity, which fully meets the calcium material requirements of aerated concrete. The calcium oxide generated during calcination digests with water at high temperatures, causing changes in the microstructure of the digestion product, calcium hydroxide. High-temperature digestion generates a large amount of steam, significantly increasing the specific surface area and pore structure of calcium hydroxide. During autoclaving, calcium ions are more easily dissolved and diffused from the surface, thus promoting the calcium-silicon reaction process. In addition, the calcium oxide generated during calcination can react with SiO2, Al2O3, Fe2O3, and other substances in granite waste powder to form some wollastonite, dicalcium silicate, and calcium ferrite, among other hydraulic minerals. These minerals react during autoclaving to generate a large amount of hydration products, which is beneficial for improving the strength of aerated concrete.

[0014] Coal gangue (SiO2 source): Siliceous coal gangue also contains siliceous materials (SiO2). During the calcination process of siliceous coal gangue, the clay minerals contained therein dehydrate and decompose, releasing some more active amorphous SiO2, which improves the reactivity of siliceous and calcareous materials. The SiO2 reacts with CaO to generate hydraulic minerals such as wollastonite (CaSiO3) and dicalcium silicate (2CaO·SiO2), which enhance the later strength of aerated concrete.

[0015] Red mud (Al2O3 source): Red mud is an industrial solid waste discharged during the extraction of alumina in the aluminum industry. It contains Al2O3 and can also play a good role in gel filling in aerated concrete. Its synergistic effect with the rigid skeleton formed by granite waste stone powder significantly improves the strength of environmentally friendly aerated concrete blocks.

[0016] This invention involves mixing and heating granite waste powder, clay, coal gangue, carbide slag, and red mud to form a calcined material. Then, saline-alkaline wastewater is added and mixed to form a slurry. The high alkalinity environment breaks Si-O-Si and Al-O-Si bonds, promotes the dissociation of amorphous SiO2 in the coal gangue, increases the hydration reaction rate, and accelerates CSH gel nucleation. The Na+ in the alkaline wastewater... + K + With Ca 2+ (CaO reacts with water to form Ca(OH)2) to form ionic synergy, stabilizing the CSH gel structure and reducing drying shrinkage during subsequent steam curing. The Cl⁻ in alkaline wastewater promotes tobermorite crystal nucleation during the steam curing process of aerated concrete, refining the pore structure. The SO₄²⁻ in alkaline wastewater... 2- With Ca 2+ The formation of ettringite (AFt) can fill the voids in concrete, thereby improving the compressive strength of aerated concrete.

[0017] Preferably, in step S1, the granite waste rock is subjected to jaw crushing, shaping and screening to obtain granite waste rock powder. The granite waste rock powder with a particle size of 5-20mm is used as coarse aggregate, and the granite waste rock powder with a particle size of 0.15-5mm is used as fine aggregate. The mass ratio of coarse aggregate to fine aggregate is (2.5-3.5):1.

[0018] Preferably, in step S1, the heat preservation time is 20-30 minutes.

[0019] Preferably, the mass ratio of the granite waste powder, clay, coal gangue, carbide slag, and red mud is (25-30):(0.5-1):(1-3):(10-15):1.

[0020] Preferably, in step S2, the parameters for the cooling process are: the cooling endpoint is 100-200℃, and the cooling rate is ≥100℃ / min.

[0021] Preferably, the alkaline wastewater has a salt content of 2-5 wt%, and the salts are sulfates and / or chlorides.

[0022] Preferably, sodium hydroxide is added to adjust the pH of the saline-alkaline wastewater to 11-13.

[0023] Preferably, the clay is at least one of bentonite, Suzhou clay, and kaolin, and more preferably bentonite.

[0024] Preferably, the water-reducing agent is a polycarboxylate water-reducing agent and / or sodium naphthalene sulfonate water-reducing agent.

[0025] Preferably, the foaming agent is at least one of aluminum powder, hydrogen peroxide, and bleaching powder.

[0026] Preferably, in step S2, the ball milling rate is 30-50 r / min and the ball milling time is 10-20 min.

[0027] Preferably, in step S4, the steam curing temperature is 160-180℃, the steam curing pressure is 1-2MPa, and the steam curing time is 8-11h.

[0028] In a second aspect, the present invention provides an aerated concrete prepared using granite waste powder, which is prepared by the preparation method described in the first aspect.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] (1) The aerated concrete of the present invention uses granite waste stone powder (as a skeleton), carbide slag (calcareous material), clay (to promote sintering), red mud (gel filler), and coal gangue (siliceous material) as core raw materials to replace traditional natural sand and lime, realize the resource utilization of industrial solid waste, conform to the development direction of green building materials, and significantly reduce the dependence on natural resources.

[0031] (2) To solve the technical problem of the difficulty in dispersing granite waste powder in concrete systems, this invention first calcines the granite waste powder into ceramics. Because ceramics and aerated concrete have similar structures and expansion coefficients, the compatibility between the granite waste powder and the aerated concrete system is improved. This invention also mixes the calcined material with saline-alkaline wastewater to form a slurry, further improving the dispersibility of granite waste powder in the system.

[0032] (3) The present invention uses saline alkaline wastewater as an alkaline activator, which can significantly increase the alkalinity of the slurry, promote the decomposition of Si-O bonds and Al-O bonds, improve the hydration reaction activity during subsequent steam curing, generate more hydration products such as CSH and CAH, thereby improving the mechanical properties and durability of aerated concrete. Attached Figure Description

[0033] Figure 1 The present invention provides a process flow diagram for preparing aerated concrete. Detailed Implementation

[0034] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0035] The sources of the raw materials used in the following examples and comparative examples are as follows:

[0036] Granite waste powder: sourced from Yongda Granite Stone Factory, Yuncheng District, Yunfu City;

[0037] Bentonite: Manufacturer: Dongguan Ruiheng Mineral Products Co., Ltd.; Model: Calcium-based bentonite.

[0038] Coal gangue: sourced from Guangdong Yuelong Power Plant;

[0039] Calcium carbide slag: sourced from Guangdong Liweida Mining Co., Ltd.;

[0040] Red mud: sourced from Xinxing County Fenghang Aluminum Industry Co., Ltd.;

[0041] Cement: Manufacturer is Huizhou Tapai Cement Co., Ltd., model is PO 42.5R;

[0042] Gypsum: Desulfurized gypsum, manufactured by Meizhou Jiayuan Environmental Protection Building Materials Co., Ltd.

[0043] Polycarboxylate superplasticizer: Manufacturer: Guangdong Hongqiu Building Materials Technology Co., Ltd.; Model: HQ-PC1;

[0044] Sodium naphthalene sulfonate water-reducing agent: Manufacturer: Guangdong Hongqiu Building Materials Technology Co., Ltd., Model: HQ-1;

[0045] The saline-alkaline wastewater originated from the comprehensive wastewater of a steel enterprise in Yunfu. The main ion contents are shown in Table 1.

[0046] Table 1. Main ion content of saline-alkaline wastewater used in the examples and comparative examples

[0047] Types of ions Content (mg / L) <![CDATA[Ca 2+ ]]> 186 <![CDATA[Mg 2 ]]> 52 <![CDATA[Na + ]]> 129 <![CDATA[Cl - ]]> 253 <![CDATA[SO4 2- ]]> 510 <![CDATA[HCO3 - ]]> 248

[0048] Unless otherwise specified, all other materials and reagents used in the examples are commercially available.

[0049] Example 1

[0050] like Figure 1 As shown, a method for preparing aerated concrete using granite waste powder includes the following steps:

[0051] S1. The granite waste rock is subjected to jaw crushing, shaping, and screening to obtain granite waste rock powder. The granite waste rock powder with a particle size of 5-10mm is used as coarse aggregate, and the granite waste rock powder with a particle size of 1-5mm is used as fine aggregate. The mass ratio of coarse aggregate to fine aggregate is 3:1. Then, the granite waste rock powder and clay are mixed first, and then coal gangue, carbide slag, and red mud are added and mixed. The mixture is heated to 1100℃ and held for 25 minutes to obtain calcined material. The mass ratio of granite waste rock powder, clay, coal gangue, carbide slag, and red mud is 28:0.6:2:13:1, and the clay is bentonite.

[0052] S2. The calcined material is cooled to 150°C at a cooling rate of 100°C / min, then mixed with saline-alkaline wastewater, and ball-milled at a rate of 40 r / min for 15 min to obtain the granite-based slurry; wherein, sodium hydroxide is added to adjust the pH of the saline-alkaline wastewater to 12, and the solid content of the granite-based slurry is 65 wt%.

[0053] S3. Mix granite-based slurry, cement, gypsum, and water-reducing agent, then add foaming agent and mix again to obtain a mixed slurry; wherein the mass ratio of granite-based slurry, cement, gypsum, water-reducing agent, and foaming agent is 100:8:4:2:1; the water-reducing agent is a polycarboxylate water-reducing agent, and the foaming agent is bleaching powder;

[0054] S4. The mixed slurry is injected into the mold, left to stand, demolded and divided, and steam cured to obtain the aerated concrete; wherein the steam curing temperature is 170℃, the steam curing pressure is 1.5MPa, and the steam curing time is 10h.

[0055] Example 2

[0056] like Figure 1 As shown, a method for preparing aerated concrete using granite waste powder includes the following steps:

[0057] S1. The granite waste rock is subjected to jaw crushing, shaping, and screening to obtain granite waste rock powder. The granite waste rock powder with a particle size of 5-10mm is used as coarse aggregate, and the granite waste rock powder with a particle size of 1-5mm is used as fine aggregate. The mass ratio of coarse aggregate to fine aggregate is 2.5:1. Then, the granite waste rock powder and clay are mixed first, and then coal gangue, carbide slag, and red mud are added and mixed. The mixture is heated to 1050℃ and held for 30 minutes to obtain calcined material. The mass ratio of granite waste rock powder, clay, coal gangue, carbide slag, and red mud is 25:0.5:1:10:1. The clay is bentonite.

[0058] S2. The calcined material is cooled to 100℃ at a cooling rate of 100℃ / min, then mixed with saline-alkaline wastewater, and ball-milled at a rate of 30r / min for 20min to obtain the granite-based slurry; wherein, sodium hydroxide is added to adjust the pH of the saline-alkaline wastewater to 11, and the solid content of the granite-based slurry is 60wt%;

[0059] S3. Mix granite-based slurry, cement, gypsum, and water-reducing agent, then add foaming agent and mix again to obtain a mixed slurry; wherein the mass ratio of granite-based slurry, cement, gypsum, water-reducing agent, and foaming agent is 100:5:1:1:1, the water-reducing agent is sodium naphthalene sulfonate water-reducing agent, and the foaming agent is aluminum powder.

[0060] S4. The mixed slurry is injected into the mold, left to stand, demolded and divided, and steam cured to obtain the aerated concrete; wherein the steam curing temperature is 160℃, the steam curing pressure is 2MPa, and the steam curing time is 11h.

[0061] Example 3

[0062] like Figure 1 As shown, a method for preparing aerated concrete using granite waste powder includes the following steps:

[0063] S1. The granite waste rock is subjected to jaw crushing, shaping, and screening to obtain granite waste rock powder. The granite waste rock powder with a particle size of 5-10mm is used as coarse aggregate, and the granite waste rock powder with a particle size of 1-5mm is used as fine aggregate. The mass ratio of coarse aggregate to fine aggregate is 3.5:1. Then, the granite waste rock powder and clay are mixed first, and then coal gangue, carbide slag, and red mud are added and mixed. The mixture is heated to 1250℃ and held for 20 minutes to obtain calcined material. The mass ratio of granite waste rock powder, clay, coal gangue, carbide slag, and red mud is 30:1:3:15:1, and the clay is bentonite.

[0064] S2. The calcined material is cooled to 200℃ at a cooling rate of 100℃ / min, then mixed with saline-alkaline wastewater, and ball-milled at a rate of 50r / min for 10min to obtain the granite-based slurry; wherein, sodium hydroxide is added to adjust the pH of the saline-alkaline wastewater to 13, and the solid content of the granite-based slurry is 70wt%;

[0065] S3. Mix granite-based slurry, cement, gypsum, and water-reducing agent, then add foaming agent and mix again to obtain a mixed slurry; wherein the mass ratio of granite-based slurry, cement, gypsum, water-reducing agent, and foaming agent is 100:10:5:3:3, the water-reducing agent is a polycarboxylate water-reducing agent, and the foaming agent is hydrogen peroxide with a mass concentration of 50%;

[0066] S4. The mixed slurry is injected into the mold, left to stand, demolded and divided, and steam cured to obtain the aerated concrete; wherein the steam curing temperature is 180℃, the steam curing pressure is 1MPa, and the steam curing time is 8h.

[0067] Example 4

[0068] The difference between Example 4 and Example 1 is that in step S1, the total mass of granite waste powder, clay, coal gangue, carbide slag, and red mud remains unchanged, and the mass ratio of granite waste powder, clay, coal gangue, carbide slag, and red mud is 20:0.5:2:5:1.

[0069] Example 5

[0070] The difference between Example 5 and Example 1 is that in step S1, the total mass of granite waste powder, clay, coal gangue, carbide slag, and red mud remains unchanged, and the mass ratio of granite waste powder, clay, coal gangue, carbide slag, and red mud is 30:1:5:15:1.

[0071] Comparative Example 1

[0072] The difference between Comparative Example 1 and Example 1 is that in step S1, the total mass of granite waste stone powder, clay, coal gangue, carbide slag, and red mud remains unchanged, and the mass ratio of granite waste stone powder, clay, coal gangue, carbide slag, and red mud is 13:0.6:2:28:1.

[0073] Comparative Example 2

[0074] The difference between Comparative Example 2 and Example 1 is that in step S1, the total mass of granite waste stone powder, clay, coal gangue, carbide slag, and red mud remains unchanged, and the mass ratio of granite waste stone powder, clay, coal gangue, carbide slag, and red mud is 28:0.6:13:2:1.

[0075] Comparative Example 3

[0076] The difference between Comparative Example 3 and Example 1 is that in step S1, the total mass of granite waste stone powder, clay, coal gangue, carbide slag, and red mud remains unchanged, and the mass ratio of granite waste stone powder, clay, coal gangue, carbide slag, and red mud is 28:1:2:13:0.6.

[0077] Comparative Example 4

[0078] The difference between Comparative Example 4 and Example 1 is that no clay is added to the aerated concrete of Comparative Example 4, and the missing amount is made up by granite waste stone powder.

[0079] Comparative Example 5

[0080] The difference between Comparative Example 5 and Example 1 is that in step S1, the heating temperature is set to 1000°C.

[0081] Comparative Example 6

[0082] The difference between Comparative Example 6 and Example 1 is that the saline-alkaline wastewater was replaced with an equal amount of deionized water.

[0083] Comparative Example 7

[0084] The difference between Comparative Example 7 and Example 1 is that in step S2, the pH of the saline alkaline wastewater is adjusted to 8.

[0085] Performance testing

[0086] Test method: Ten standard specimens (4cm×4cm×16cm) of aerated concrete from Examples 1-5 and Comparative Examples 1-7 were prepared. Each standard specimen was then cured in a standard curing chamber at 20℃ and 85% humidity for 24 hours, and finally cured in water at 20℃ for 28 days. The compressive strength of each standard specimen was tested according to the requirements of the "Test Method for Strength of Cement Mortar" specified in standard GB / T17671-1999. The average compressive strength of the ten standard specimens corresponding to Examples 1-5 and Comparative Examples 1-7 was recorded in Table 2.

[0087] Table 2 Compressive strength data of each group of samples

[0088] sample Compressive strength / MPa Example 1 61.2 Example 2 59.3 Example 3 60.6 Example 4 56.7 Example 5 57.9 Comparative Example 1 50.7 Comparative Example 2 52.5 Comparative Example 3 53.1 Comparative Example 4 45.7 Comparative Example 5 47.0 Comparative Example 6 49.7 Comparative Example 7 50.8

[0089] As shown in Table 1, and in conjunction with the data from Examples 1 and 4-5, when the mass ratio of the granite waste powder, clay, coal gangue, carbide slag, and red mud is (25-30):(0.5-1):(1-3):(10-15):1, the compressive strength of the aerated concrete is at a relatively good level.

[0090] Combining the data from Example 1 and Comparative Examples 1-3, it can be seen that in Comparative Example 1, the proportion of carbide slag (calcium source) increased significantly while the proportion of granite waste powder (skeleton component) decreased, leading to a decrease in material density and a significant reduction in compressive strength. This may be due to an imbalance in the calcium-silicon ratio of the carbide slag, with excess Ca(OH)2 not fully participating in the reaction, forming free calcium, and a lack of skeleton support, resulting in a loose structure. In Comparative Example 2, the increase in coal gangue and the decrease in carbide slag also significantly reduced the compressive strength of its aerated concrete. This may be because the calcium-silicon ratio in Comparative Example 2 was too low, resulting in insufficient CSH gel generated by the hydration reaction and a decrease in the strength of the cementitious system; at the same time, the excess silica-alumina components may not have been fully sintered, resulting in insufficient activity. In Comparative Example 3, the increase in clay and the decrease in red mud reduced the compressive strength of the aerated concrete. This may be because excessive clay may lead to an excessive liquid phase during calcination, increasing the porosity of the material after sintering, while insufficient red mud affects the sintering density. The mass ratio of granite waste stone powder, clay, coal gangue, carbide slag, and red mud in this invention should be (20-30): (0.5-1): (2-5): (5-15): 1. Within this range, the chemical composition and mineral balance are achieved, and the compressive strength of the aerated concrete is within a relatively optimal range.

[0091] Based on the data from Example 1 and Comparative Example 4, it can be seen that the absence of clay in Comparative Example 4 significantly reduced the mechanical strength of the aerated concrete. This may be because the lack of clay resulted in insufficient binding of the raw materials during calcination, leading to a loose structure after sintering. Furthermore, the lack of clay reduced the amount of ceramics formed. The absence of the porous structure of the ceramics decreased the compatibility of the granite waste powder with the aerated concrete system, making the prepared aerated concrete less prone to cracking and deformation. Simultaneously, the rigid skeleton formed by the ceramics after calcination of the granite waste powder also increased the strength of the aerated concrete.

[0092] Based on the data from Example 1 and Comparative Example 5, it can be seen that when the heating temperature of Comparative Example 5 is reduced to 1000℃, the compressive strength of its aerated concrete decreases significantly. This may be because the calcination temperature is insufficient, the granite waste stone powder and the minerals in the clay do not react fully to form ceramics, and the amount of active SiO2 and Al2O3 generated is low, resulting in insufficient raw materials for the subsequent hydration reaction and thus insufficient cementitious products.

[0093] Based on the data from Example 1 and Comparative Examples 6-7, it can be seen that in Comparative Example 6, replacing the saline alkaline wastewater used for mixing with deionized water significantly reduced the compressive strength of the aerated concrete. This may be because the alkaline wastewater can provide OH⁻ to activate the aluminosilicate raw materials, promoting their dissolution and participation in the hydration reaction; deionized water lacks an alkaline environment, the activity of the raw materials is not fully activated, the amount of CSH gel generated is reduced, and the slurry dispersibility is poor. In Comparative Example 7, the pH of the wastewater used for mixing was adjusted to 8 (neutral to alkaline), and its compressive strength was significantly lower than that of Example 1. This may be because the lower pH value led to insufficient alkalinity, reducing the dissolution rate and extent of the aluminosilicate raw materials, slowing down the hydration reaction rate, and resulting in a loose structure of the generated gel products.

[0094] In summary, Example 1 employed an optimized raw material ratio (granite waste powder: clay: coal gangue: carbide slag: red mud = (20-30): (0.5-1): (2-5): (5-15): 1) and process parameters (calcination temperature 1050-1250℃, holding time 20-30 min, pH of alkaline wastewater 11-13, etc.). Under these conditions, granite waste powder and clay sinter to form rigid ceramics and provide a skeletal structure. Coal gangue, after calcination, generates active silica-alumina components, carbide slag provides a calcium source, red mud regulates sintering performance, and the alkaline environment promotes hydration reactions to generate high-strength products such as CSH gel. Therefore, the expected compressive strength is high.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for producing an aerated concrete using a ground waste rock of granite, characterized by, The method comprises the following steps: S1, mixing granite waste rock powder and clay first, then adding coal gangue, carbide slag and red mud, heating to 1050-1250℃ and then keeping temperature to obtain calcined material; the mass ratio of the granite waste rock powder, clay, coal gangue, carbide slag and red mud is (20-30):(0.5-1):(2-5):(5-15):1; S2, cooling treatment of the calcined material, then adding salt-containing alkaline wastewater for mixing, ball milling to obtain granite stone-based slurry; wherein the pH of the salt-containing alkaline wastewater is 11-13, and the solid content of the granite stone-based slurry is 60-70wt%; S3, mixing and stirring the granite stone-based slurry, cement, gypsum and water reducing agent, then adding foaming agent for mixing and stirring to obtain mixed slurry; wherein the mass ratio of the granite stone-based slurry, cement, gypsum, water reducing agent and foaming agent is 100:(5-10):(1-5):(1-3):(1-3); S4, pouring the mixed slurry into a mold, standing, demolding and segmenting, and then steam curing to obtain the aerated concrete.

2. The method for preparing aerated concrete using granite waste powder as described in claim 1, characterized in that, In the step S1, the temperature keeping time is 20-30min.

3. The method of claim 1, wherein the air entrained concrete is prepared by mixing the granite waste rock powder with cement, sand, water, and an air entraining agent. In the step S1, the granite waste rock is subjected to jaw crushing, shaping and screening to obtain granite waste rock powder, the granite waste rock powder with a particle size of 5-20mm is used as coarse aggregate, and the granite waste rock powder with a particle size of 0.15-5mm is used as fine aggregate, and the mass ratio of the coarse aggregate and the fine aggregate is (2.5-3.5):

1.

4. The method of claim 1, wherein the air entrained concrete is prepared by mixing the granite waste rock powder with cement, sand, water, and an air entraining agent. The mass ratio of the granite waste rock powder, clay, coal gangue, carbide slag and red mud is (25-30):(0.5-1):(1-3):(10-15):

1.

5. The method of claim 1, wherein the air entrained concrete is prepared by mixing the granite waste rock powder with cement, sand, water, and an air entraining agent. In the step S2, the cooling treatment parameters are as follows: the final cooling temperature is 100-200℃, and the cooling rate is ≥100℃ / min.

6. The method of claim 1, wherein the air entrained concrete is prepared by mixing the granite waste rock powder with cement, sand, water, and an air entraining agent. The salt content of the alkaline wastewater is 2-5wt%, and the types of salt are sulfate and / or chloride.

7. The method of claim 1, wherein the air entrained concrete is prepared by mixing the granite waste rock powder with cement, sand, water, and an air entraining agent. The water reducing agent is polycarboxylic acid water reducing agent and / or naphthalene sulfonate sodium salt water reducing agent; and / or, the foaming agent is at least one of aluminum powder, hydrogen peroxide and bleaching powder.

8. The method of claim 1, wherein the air entrained concrete is prepared by mixing the granite waste rock powder with cement, sand, water, and an air entraining agent. In the step S2, the ball milling rate is 30-50r / min, and the ball milling time is 10-20min.

9. The method of claim 1, wherein the air entrained concrete is prepared by mixing the granite waste rock powder with cement, sand, water, and an air entraining agent. In the step S4, the steam curing temperature is 160-180℃, the steam curing pressure is 1-2MPa, and the steam curing time is 8-11h.

10. An aerated concrete prepared using granite mill waste, characterized in that, The aerated concrete prepared by the method of any one of claims 1-9.

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