Aerated concrete prepared from granite waste stone powder and preparation method thereof

Abstract

The invention relates to aerated concrete prepared from granite waste stone powder and a preparation method thereof.The aerated concrete takes granite waste stone powder (under the skeleton effect), carbide slag (calcium material), clay (promoting sintering), red mud (gel filling) and coal gangue (siliceous material) as core raw materials to replace traditional natural gravel and lime; industrial solid waste resource utilization is achieved, the development direction of green building materials is met, and dependence on natural resources is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aerated concrete, and particularly relates to aerated concrete prepared from granite waste stone powder and a preparation method thereof. BACKGROUND

[0002] At present, the stone processing industry in Fujian, Guangdong and other regions is showing a vigorous development trend. However, in the stone processing process, a large amount of waste such as granite waste stone powder will be generated, which poses a serious threat to the local ecological environment. Granite waste stone powder is essentially composed of fine particles of silicate minerals (such as quartz, feldspar, hornblende, etc.). If the granite waste stone powder can be used in ultra-high performance concrete to partially replace cementitious materials (such as cement, silica fume, etc.), it will be expected to bring significant economic and environmental benefits.

[0003] However, granite waste stone powder has a thorny problem, that is, it is prone to clumping due to moisture. In actual application, it usually needs to be specifically pretreated, which not only increases the disposal cost, but also may cause secondary pollution. In addition, from the principle of thermodynamics, when the wet granite waste stone powder solid particles are dispersed, the free energy of the dispersion system will increase, resulting in an unstable system, and the dispersed particles have the tendency to coagulate, eventually forming lumpy wet granite waste stone powder. This condition is not conducive to the uniform mixing of concrete. Therefore, it is of important research value and application prospect to deeply explore the application method of wet granite waste stone powder in concrete and optimize the preparation process of ultra-high performance concrete. SUMMARY

[0004] The present application aims to overcome the deficiencies of the prior art and provide an aerated concrete prepared from granite waste stone powder and a preparation method thereof.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0006] In the first aspect, the present application provides a preparation method of aerated concrete prepared from granite waste stone powder, comprising the following steps:

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

[0008] S2, the calcined material is subjected to a cooling treatment, and then salt-containing alkaline wastewater is added and mixed, and ball milling is performed, to obtain the 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 60-70 wt%;

[0009] S3, the granite stone-based slurry, cement, gypsum and water reducing agent are stirred and mixed, and then a foaming agent is added and stirred and mixed, to obtain a 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);

[0010] S4, the mixed slurry is injected into a mold, and then left to stand, demolded and segmented, and subjected to steam curing, to obtain the aerated concrete.

[0011] The present application solves the dispersion problem of granite waste stone powder in the concrete system in a systematic way, and realizes the high-value utilization of industrial solid waste, and the roles of the raw materials are as follows:

[0012] Granite waste stone powder (skeleton support + silicon aluminum source): The granite waste stone powder mainly contains quartz, feldspar and mica, and clay is the main binder, which can combine feldspar and quartz and other materials; quartz has a high melting point, which plays a role of skeleton during sintering, can reduce drying and shrinkage caused by sintering, and enhance the wear resistance, strength and chemical stability of the body and glaze; feldspar has a melting property, which can make the body easy to sinter. The granite waste stone powder of the present application can generate ceramics at a calcination temperature of 1050-1250 DEG C with clay, and the ceramic surface is hard, and the inside is fine honeycomb-shaped micropores. This structure limits its expansion behavior to a certain extent. There are also a large number of pores in the aerated concrete, which also affect its expansion behavior. The similar porous structure makes their linear expansion coefficients close when the temperature changes, which can effectively reduce the cracks and deformation caused by temperature changes, and also improves the compatibility of the granite waste stone powder in the aerated concrete system, so that the prepared aerated concrete is not easy to crack and deform. At the same time, the rigid skeleton formed by the ceramics formed by the calcination of the granite waste stone powder also increases the strength of the aerated concrete.

[0013] Carbide slag (CaO source): The chemical composition of carbide slag is mainly Ca(OH)2, and CaO is produced by burning and losing water. This is different from traditional lime prepared by burning limestone. In addition, the dehydration temperature of the carbide slag in the present invention is low and no CO is emitted. The generated CaO is more active and can fully meet the calcium material needs and requirements of aerated concrete. The calcium oxide generated during the calcination process is digested by water under high temperature conditions, and the microstructure of the digestion product, calcium hydroxide, changes. A large amount of steam is generated during high-temperature digestion, which significantly increases the specific surface area and pore structure of calcium hydroxide. During the autoclave curing process, calcium ions are more easily dissolved and diffused from the surface, thereby promoting the silicon-calcium reaction process. In addition, the calcium oxide generated during the calcination process can react with SiO2, Al2O3, Fe2O3 and other substances in the granite waste stone powder to generate some water-hardening minerals such as wollastonite, dicalcium silicate and calcium ferrite. These minerals react to generate a large amount of hydration products during the autoclave curing process, which is beneficial to improving the strength of aerated concrete.

[0014] Gangue (SiO2 source): Siliceous gangue also contains siliceous materials (SiO2). During the calcination process of siliceous gangue, the clay minerals contained in it are dehydrated and decomposed to release some more active amorphous SiO2, which increases the reactivity of siliceous and calcareous materials. The SiO2 reacts with CaO to form hydraulic minerals such as wollastonite (CaSiO3) and dicalcium silicate (2CaO·SiO2), which enhances the later strength of aerated concrete.

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

[0016] In the present invention, granite waste stone powder, clay, coal gangue, carbide slag and red mud are mixed and heated to form a calcined material, and then saline alkaline wastewater is added to form a slurry. The high alkalinity environment can break the Si-O-Si and Al-O-Si bonds, promote the dissociation of amorphous SiO2 in the coal gangue, increase the hydration reaction rate, and accelerate the nucleation of CSH gel. + , K + With Ca 2+ (CaO and water generate Ca(OH)2) to form ion synergy, stabilize the CSH gel structure, and reduce drying shrinkage during the subsequent steam curing process. The Cl- contained in the alkaline wastewater can promote the nucleation of tobermorite crystals during the steam curing process of aerated concrete, refine the pore structure, and the SO4 contained in the alkaline wastewater 2- With Ca 2+ The generated ettringite (AFt) can fill the voids in the concrete, thereby improving the compressive strength of the 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 5-20 mm is used as coarse aggregate, and the granite waste rock powder with a particle size of 0.15-5 mm is used as fine aggregate, and the mass ratio of the coarse aggregate to the fine aggregate is (2.5-3.5) : 1.

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

[0019] Preferably, 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.

[0020] Preferably, in step S2, the parameters for the cooling treatment are as follows: the final cooling temperature is 100-200℃, and the cooling rate is ≥100℃ / min.

[0021] Preferably, the salt content of the alkaline wastewater is 2-5wt%, and the types of the salt are sulfate and / or chloride.

[0022] Preferably, the pH of the salt-containing alkaline wastewater is adjusted to 11-13 by adding sodium hydroxide.

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

[0024] Preferably, the water reducing agent is polycarboxylic acid water reducing agent and / or naphthalene sulfonate sodium salt water reducing agent.

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

[0026] Preferably, in step S3, the ball milling rate is 30-50 r / min, and the ball milling time is 10-20 min.

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

[0028] In a second aspect, the application provides an aerated concrete prepared from granite waste rock powder, which is prepared by the preparation method in the first aspect.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] (1) The aerated concrete of the present application takes granite waste stone powder (skeleton effect), carbide slag (calcic material), clay (promotes sintering), red mud (gel filling), 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.

[0031] (2) To solve the technical problem that granite waste stone powder is difficult to disperse in the concrete system, the granite waste stone powder is first calcined to make ceramic, because the structure of ceramic is similar to that of aerated concrete, and the expansion coefficients of the two are also similar, so the compatibility of the subsequent granite waste stone powder and the aerated concrete system is improved. The calcined material is mixed with saline-alkaline wastewater to make slurry, which further improves the dispersibility of the granite waste stone powder in the system.

[0032] (3) The present application selects saline-alkaline wastewater as an alkaline activator, which can significantly improve 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 C-S-H, C-A-H and other hydration products, thereby improving the mechanical properties and durability of the aerated concrete. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A process flow chart for preparing aerated concrete is provided. DETAILED DESCRIPTION

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

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

[0036] Granite waste stone powder: from Yongda Granite Stone Factory in Yunfu City;

[0037] Bentonite: from Dongguan Ruisheng Mineral Products Co., Ltd., model: calcium-based bentonite;

[0038] Coal gangue: from Guangdong Yuteng Power Plant;

[0039] Carbide slag: from Guangdong Liweida Mining Co., Ltd.;

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

[0041] Cement: from Huizhou Taipai Cement Co., Ltd., model: P.O 42.5R;

[0042] Gypsum: desulfurization gypsum, from Meizhou Jiayuan Environmental Protection Building Material Co., Ltd.;

[0043] Polycarboxylic acid water reducer: manufacturer is Guangdong Hongqiu Building Material Technology Co., Ltd., model is HQ-PC1;

[0044] Naphthalene sulfonate sodium salt water reducer: manufacturer is Guangdong Hongqiu Building Material Technology Co., Ltd., model is HQ-1;

[0045] The salt-containing alkaline wastewater is derived from a comprehensive wastewater of a certain steel enterprise in Yunfu, and the main ion content is shown in Table 1.

[0046] Table 1 Main ion content of salt-containing alkaline wastewater used in examples and comparative examples

[0047] Ion species Content (mg / L) Ca 2+ ]] 186 Mg 2 ]]> 52 Na + ]] 129 Cl- 253 SO4 2- ]] 510 [HCO3-] 248

[0048] Other materials, reagents, etc. used in the examples can be obtained from commercial channels if there is no special instruction.

[0049] Example 1

[0050] As shown in Figure 1 A preparation method of aerated concrete prepared by using granite waste stone powder, comprising the following steps:

[0051] S1, the granite waste stone is jaw broken, shaped and screened to obtain granite waste stone powder, the granite waste stone powder with a particle size of 5-10 mm is used as coarse aggregate, and the granite waste stone powder with a particle size of 1-5 mm is used as fine aggregate, the mass ratio of the coarse aggregate to the fine aggregate is 3:1, then the granite waste stone powder and clay are mixed, coal gangue, calcium carbide slag and red mud are added, heated to 1100℃ and then kept for 25 min to obtain calcined material; the mass ratio of the granite waste stone powder, clay, coal gangue, calcium 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℃ at a cooling rate of 100℃ / min, then the salt-containing alkaline wastewater is added and mixed, and ball milling is performed at a speed of 40 r / min for 15 min to obtain the granite stone-based slurry; wherein the pH of the salt-containing alkaline wastewater adjusted by sodium hydroxide is 12, and the solid content of the granite stone-based slurry is 65wt%;

[0053] S3, the granite stone-based slurry, cement, gypsum and water reducer are stirred and mixed, then the foaming agent is added and stirred and mixed to obtain a mixed slurry; wherein the mass ratio of the granite stone-based slurry, cement, gypsum, water reducer and foaming agent is 100:8:4:2:1; the water reducer is polycarboxylic acid water reducer, and the foaming agent is bleaching powder;

[0054] S4, injecting the mixed slurry into a mold, standing, demolding and segmenting, and performing steam curing to obtain the aerated concrete; wherein the temperature of the steam curing is 170 DEG C, the pressure of the steam curing is 1.5 MPa, and the time of the steam curing is 10 h.

[0055] Example 2

[0056] As shown in Figure 1 a preparation method of an aerated concrete prepared by using granite waste rock powder, comprising the following steps:

[0057] S1, crushing, shaping and screening the granite waste rock to obtain granite waste rock powder, taking the granite waste rock powder with a particle size of 5-10 mm as coarse aggregate and the granite waste rock powder with a particle size of 1-5 mm as fine aggregate, the mass ratio of the coarse aggregate to the fine aggregate being 2.5:1, then mixing the granite waste rock powder and clay, adding coal gangue and carbide slag, adding red mud, heating to 1050 DEG C and then keeping the temperature for 30 min to obtain calcined material; the mass ratio of the granite waste rock powder, the clay, the coal gangue, the carbide slag and the red mud being 25:0.5:1:10:1, and the clay being bentonite;

[0058] S2, cooling the calcined material to 100 DEG C at a cooling rate of 100 DEG C / min, then adding salt-containing alkaline wastewater to mix, and ball milling at a speed of 30 r / min for 20 min to obtain the granite stone-based slurry; wherein the pH of the salt-containing alkaline wastewater adjusted by adding sodium hydroxide is 11, and the solid content of the granite stone-based slurry is 60 wt%;

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

[0060] S4, injecting the mixed slurry into a mold, standing, demolding and segmenting, and performing steam curing to obtain the aerated concrete; wherein the temperature of the steam curing is 170 DEG C, the pressure of the steam curing is 1.5 MPa, and the time of the steam curing is 10 h.

[0061] Example 3

[0062] As shown in Figure 1 Figure 1 a preparation method of an aerated concrete prepared by using granite waste rock powder, comprising 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 5-10 mm is used as coarse aggregate, and the granite waste rock powder with a particle size of 1-5 mm is used as fine aggregate, the mass ratio of the coarse aggregate to the fine aggregate is 3.5:1, then the granite waste rock powder and clay are mixed, coal gangue and carbide slag are added, and the mixture is heated to 1250 DEG C and then kept for 20 min to obtain calcined material; the mass ratio of the 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 DEG C at a cooling rate of 100 DEG C / min, and then mixed with salt-containing alkaline wastewater, and then ball milled at a speed of 50 r / min for 10 min to obtain the granite stone-based slurry; wherein the pH of the salt-containing alkaline wastewater adjusted by sodium hydroxide is 13, and the solid content of the granite stone-based slurry is 70 wt%;

[0065] S3, the granite stone-based slurry, cement, gypsum and water reducing agent are stirred and mixed, and then a foaming agent is added and stirred and mixed to obtain a mixed slurry; wherein the mass ratio of the granite stone-based slurry, cement, gypsum, water reducing agent and foaming agent is 100:10:5:3:3, the water reducing agent is polycarboxylic acid water reducing agent, and the foaming agent is hydrogen peroxide with a mass concentration of 50%;

[0066] S4, the mixed slurry is injected into a mold, left to stand, demolded and segmented, and then subjected to steam curing to obtain the aerated concrete; wherein the temperature of the steam curing is 180 DEG C, the pressure of the steam curing is 1 MPa, and the time of the steam curing is 8 h.

[0067] Example 4

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

[0069] Example 5

[0070] Example 5 differs from Example 1 in that in step S1, the total mass of the granite waste rock powder, clay, coal gangue, carbide slag and red mud remains unchanged, and the mass ratio of the granite waste rock 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 the step S1, the total mass of the granite waste rock powder, clay, coal gangue, carbide slag and red mud is unchanged, and the mass ratio of the granite waste rock 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 the step S1, the total mass of the granite waste rock powder, clay, coal gangue, carbide slag and red mud is unchanged, and the mass ratio of the granite waste rock 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 the step S1, the total mass of the granite waste rock powder, clay, coal gangue, carbide slag and red mud is unchanged, and the mass ratio of the granite waste rock 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 in the aerated concrete of Comparative Example 4, and the missing amount is made up by the granite waste rock powder.

[0079] Comparative Example 5

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

[0081] Comparative Example 6

[0082] The difference between Comparative Example 6 and Example 1 is that the salt-containing alkaline wastewater is 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 the step S2, the pH of the salt-containing alkaline wastewater is adjusted to 8.

[0085] Performance test

[0086] Test method: The aerated concrete of Example 1-5 and Comparative Example 1-7 were respectively made into 4cmx4cmx16cm standard test pieces each 10, then each standard test piece was cured in a standard curing box with temperature of 20℃ and humidity of 85% for 24h, finally the compressive strength of each standard test piece was detected according to the requirements of "Cement mortar strength test method" in standard GB / T17671-1999, and the average value of the compressive strength of 10 standard test pieces of Example 1-5 and Comparative Example 1-7 was recorded in Table 2.

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

[0088]

[0089]

[0090] From Table 1, in combination with the data of Example 1 and Example 4-5, it can be known that when the mass ratio of the granite waste stone 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 better level.

[0091] In combination with the data of Example 1 and Comparative Example 1-3, it can be known that the proportion of carbide slag (calcium source) in Comparative Example 1 is greatly increased, and the granite waste stone powder (skeleton component) is reduced, which leads to the decrease of material density and the significant decrease of compressive strength, which may be because the calcium-silicon ratio of carbide slag is unbalanced, and the excess Ca(OH)2 does not fully participate in the reaction to form free calcium, and at the same time, the skeleton component is insufficient to support, leading to loose structure. In Comparative Example 2, the coal gangue is increased and the carbide slag is reduced, and the compressive strength of the aerated concrete is also significantly reduced, which may be because the calcium-silicon ratio of Comparative Example 2 is low, and the amount of C-S-H gel generated by the hydration reaction is insufficient, and the strength of the cementitious system decreases; at the same time, the excess silicon-aluminum component may not be fully sintered, and the activity is insufficient. In Comparative Example 3, the clay is increased and the red mud is reduced, and the compressive strength of the aerated concrete is reduced, which may be because the excess clay may lead to too much liquid phase during calcination, and the porosity of the material increases after sintering, and the insufficient red mud affects the sintering density. It shows that the mass ratio of the granite waste stone powder, clay, coal gangue, carbide slag and red mud of the present application should be (20-30):(0.5-1):(2-5):(5-15):1, and the chemical composition and mineral balance are in the range, and the compressive strength of the aerated concrete is in a relatively optimal range.

[0092] From the data of Example 1 and Comparative Example 4, it can be seen that the mechanical strength of the aerated concrete in Comparative Example 4 is significantly reduced due to the absence of clay, which may be because the absence of clay leads to insufficient adhesion of the raw materials during calcination, and the structure is loose after sintering. Moreover, the absence of clay leads to a decrease in the amount of ceramic formed, and the absence of the porous structure of the ceramic leads to a decrease in the compatibility of the granite waste stone powder in the aerated concrete system, making the aerated concrete prepared more difficult to crack and deform. At the same time, the rigid skeleton formed by the ceramic formed by the calcination of the granite waste stone powder also increases the strength of the aerated concrete.

[0093] From the data of Example 1 and Comparative Example 5, it can be seen that the compressive strength of the aerated concrete in Comparative Example 5 is significantly reduced due to the decrease in the heating temperature to 1000℃, which may be because the insufficient calcination temperature, the granite waste stone powder and the minerals in the clay do not react sufficiently to form ceramic, and the amount of active SiO2 and Al2O3 is small, and the subsequent hydration reaction lacks sufficient raw materials, resulting in insufficient cementitious products.

[0094] From the data of Example 1 and Comparative Examples 6-7, it can be seen that the compressive strength of the aerated concrete in Comparative Example 6 is significantly reduced due to the replacement of the alkaline wastewater used for mixing with deionized water, which may be because the alkaline wastewater can provide OH- to activate the silica-alumina raw materials, promote their dissolution and participate in the hydration reaction; the deionized water lacks an alkaline environment, the activity of the raw materials is not fully excited, the amount of C-S-H gel is reduced, and the slurry dispersibility is poor. The compressive strength of Comparative Example 7 is significantly lower than that of Example 1 due to the adjustment of the pH of the wastewater used for mixing to 8 (neutral to alkaline), which may be because the decrease in pH leads to insufficient alkalinity, the dissolution rate and extent of the silica-alumina raw materials decrease, the hydration reaction rate slows down, and the structure of the cementitious products generated is loose,

[0095] In summary, Example 1 uses an optimized raw material ratio (granite waste stone 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 20-30min, pH of alkaline wastewater 11-13, etc.). Under the above conditions, the granite waste stone powder and the clay are sintered to form a rigid ceramic and provide a skeleton structure, the coal gangue generates active silica-alumina components after calcination, the carbide slag provides a calcium source, the red mud adjusts the sintering performance, and the alkaline environment promotes the hydration reaction to generate C-S-H gel and other high-strength products, so the expected compressive strength is high.

[0096] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and do not limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for preparing aerated concrete using granite waste rock powder, characterized in that: The following steps are involved: S1. Mix granite waste stone powder and clay, then add coal gangue, carbide slag, and red mud, heat to 1050-1250° C., and then keep warm to obtain a calcined material; the mass ratio of the granite waste stone powder, clay, coal gangue, carbide slag, and red mud is (20-30): (0.5-1): (2-5): (5-15): 1; S2. Cooling the calcined material, adding saline alkaline wastewater, mixing, and ball milling to obtain the granite-based slurry; wherein the saline alkaline wastewater has a pH of 11-13, and the solid content of the granite-based slurry is 60-70 wt%; S3. Stir and mix the granite base slurry, cement, gypsum, and water reducing agent, and then add the foaming agent and stir and mix to obtain a mixed slurry; wherein the mass ratio of the granite base slurry, cement, gypsum, water reducing agent, and foaming agent is 100:(5-10):(1-5):(1-3):(1-3); S4, injecting the mixed slurry into a mold, allowing it to stand, demoulding and dividing it, and performing steam curing to obtain the aerated concrete.

2. The method for preparing aerated concrete using granite waste rock powder according to claim 1, wherein: In step S1, the insulation time is 20-30 minutes.

3. The method for preparing aerated concrete using granite waste rock powder according to claim 1, wherein: In step S1, the granite waste rock is jaw crushed, shaped and screened to obtain granite waste rock powder. The granite waste rock powder with a particle size of 5-20 mm is used as coarse aggregate, and the granite waste rock powder with a particle size of 0.15-5 mm is used as fine aggregate. The mass ratio of coarse aggregate to fine aggregate is (2.5-3.5):

1.

4. The method for preparing aerated concrete using granite waste rock powder according to claim 1, wherein: The mass ratio of the granite waste stone powder, clay, coal gangue, carbide slag and red mud is (25-30): (0.5-1): (1-3): (10-15):

1.

5. The method for preparing aerated concrete using granite waste rock powder according to claim 1, wherein: In step S2, the parameters of the cooling treatment are: the cooling end point is 100-200°C, and the cooling rate is ≥100°C / min.

6. The method for preparing aerated concrete using granite waste rock powder according to claim 1, wherein: The alkaline wastewater has a salt content of 2-5 wt %, and the types of salt are sulfate and / or chloride.

7. The method for preparing aerated concrete using granite waste rock powder according to claim 1, wherein: The water reducer is a polycarboxylate water reducer and / or a sodium naphthalenesulfonate water reducer; and / or the foaming agent is at least one of aluminum powder, hydrogen peroxide and bleaching powder; 8. The method for preparing aerated concrete using granite waste rock powder according to claim 1, wherein: In step S3, the ball milling rate is 30-50 r / min, and the ball milling time is 10-20 min.

9. The method for preparing aerated concrete using granite waste rock powder according to claim 1, wherein: In step S4, the steam curing temperature is 160-180° C., the steam curing pressure is 1-2 MPa, and the steam curing time is 8-11 hours.

10. Aerated concrete prepared using granite waste rock powder, characterized in that: The aerated concrete is prepared by the method for preparing aerated concrete using granite waste stone powder according to any one of claims 1 to 9.

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