Raw material composition for manufacturing autoclaved aerated concrete block, autoclaved aerated concrete block, and method for manufacturing the same

Abstract

The application provides a raw material composition for preparing autoclaved aerated concrete blocks, the autoclaved aerated concrete blocks and a preparation method thereof. The raw material composition comprises 70-80% of fly ash acid method aluminum extraction residue, 2-3% of power plant desulfurization gypsum, 6-13% of cement and 12-20% of quicklime. The fly ash acid method aluminum extraction residue is used as the raw material, and the porous structure and the large specific surface area of the fly ash acid method aluminum extraction residue are used, so that the fly ash acid method aluminum extraction residue is easy to have a hydration reaction with the cement and the quicklime, the dry density of the blocks can be reduced, the compressive strength of the autoclaved aerated concrete blocks is improved, the autoclaved aerated concrete blocks obtained finally have excellent mechanical strength and low dry density. Meanwhile, the industrial solid waste residue is recycled, the environmental pollution is reduced and the engineering quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of the building industry, in particular to a raw material composition for preparing autoclaved aerated concrete blocks, autoclaved aerated concrete blocks and a preparation method thereof. BACKGROUND

[0002] The autoclaved aerated concrete block is a new type of wall material with light weight and porosity, which is prepared by mixing and stirring calcium raw materials and silicon raw materials after being finely ground, a gas-forming agent and other adjusting materials, and then pouring, gas-forming, cutting and autoclaving. 3 The autoclaved aerated concrete block has the following advantages: ① light weight, with a density in the range of 500-1000 kg / m

[0003] In order to comprehensively utilize a large amount of fly ash, and in view of the characteristics of fly ash produced after combustion of coal in the Jungar coalfield, the State Energy Group successfully developed a new process of "one-step acid dissolution" for preparing alumina from fly ash, 1 ton of alumina can be extracted from 2.5 tons of fly ash, and 1.5 tons of fly ash acid extraction residue is produced at the same time. The production of fly ash seriously pollutes the environment, especially the fly ash extraction residue, which has a very fine particle size, a large specific surface area and colloidal properties. Therefore, the fly ash extraction residue is still to be developed as a raw material for autoclaved aerated concrete blocks. SUMMARY

[0004] The main purpose of the present application is to provide a raw material composition for preparing autoclaved aerated concrete blocks, autoclaved aerated concrete blocks and a preparation method thereof, so as to solve the problem of environmental pollution caused by fly ash extraction residue in the prior art.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a raw material composition for preparing autoclaved aerated concrete blocks is provided, which comprises, in terms of dry basis mass percentage, 70-80% of fly ash acid extraction residue, 2-3% of power plant desulfurization gypsum, 6-13% of cement and 12-20% of quicklime.

[0006] Further, the acid-alumina extraction residue from fly ash has a dry basis mass of: SiO2>55%, Al2O3<24%, the total mass of SiO2 and Al2O3>75%, CaO<1%, MgO<1%, and loss on ignition<13%; preferably, 90% of the acid-alumina extraction residue from fly ash has a particle size of 40-75 μm; preferably, the acid-alumina extraction residue from fly ash has a specific surface area of 60-100 m2 / g; preferably, the acid-alumina extraction residue from fly ash has an average true density of 1.3-2.35 g / cm3; and preferably, the acid-alumina extraction residue from fly ash has a bulk density of 0.4-0.6 g / cm3. 2 3 3

[0007] Further, the raw material composition further comprises a gas-releasing agent, preferably the gas-releasing agent is aluminum powder paste; preferably, the mass of the aluminum powder paste is 0.062-0.075% of the total mass of the acid-alumina extraction residue from fly ash, the desulfurization gypsum from power plants, the cement, and the quicklime; preferably, the effective Al content of the aluminum powder paste is >90%; and preferably, the particle size of the aluminum powder paste is <75 μm.

[0008] Further, the desulfurization gypsum from power plants has a water content of <16%; preferably, the content of CaSO4·2H2O in the desulfurization gypsum from power plants is >85%.

[0009] Further, the cement is 525 cement, 425 cement, or 325 cement.

[0010] Further, the quicklime has an effective CaO content of >85%, and the content of MgCO3 in the quicklime is <12%; preferably, the particle size of the quicklime is 40-75 μm.

[0011] According to another aspect of the present application, there is provided an autoclaved aerated concrete block prepared by mixing the raw material composition described above.

[0012] According to still another aspect of the present application, there is provided a method for preparing the autoclaved aerated concrete block described above, the method comprising: step S1, mixing raw materials including the acid-alumina extraction residue from fly ash, the desulfurization gypsum from power plants, the cement, the quicklime, and water to obtain a mixed slurry; and step S2, successively performing casting, gas-releasing forming, cutting, and autoclave curing on the mixed slurry to obtain the autoclaved aerated concrete block.

[0013] Further, the autoclave curing is performed under the following conditions: vacuumizing is performed at a temperature of 50-60°C in the autoclave to obtain a vacuum degree of -0.03 to -0.06 MPa, and the vacuumizing is performed for 30-60 min; and then, a stepwise temperature and pressure increasing is performed.​​​

[0014] Further, the process of the above-mentioned stepwise temperature rising and pressure increasing operation comprises: sequentially maintaining at 60-70℃ for 45-60min, 75-85℃ for 10-30min, 130-145℃ for 10-30min, and 175-188℃ for 420-480min.

[0015] By using the fly ash acid method aluminum extraction residue as raw material, and by using the characteristics that the fly ash acid method aluminum extraction residue has a porous structure and a large specific surface area, and is easy to have a hydration reaction with cement and quicklime, the dry density of the block can be reduced, the compressive strength of the autoclaved aerated concrete block can be improved, and thus the autoclaved aerated concrete block obtained finally has excellent mechanical strength and low dry density. Meanwhile, the resource utilization of industrial solid waste residue is realized, environmental pollution is reduced, and engineering quality is improved. DETAILED DESCRIPTION

[0016] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments.

[0017] As analyzed in the background art, there is an environmental pollution problem caused by fly ash acid method aluminum extraction residue in the prior art. In order to solve the problem, the present application provides a raw material composition for preparing an autoclaved aerated concrete block, an autoclaved aerated concrete block, and a preparation method thereof.

[0018] In a typical embodiment of the present application, a raw material composition for preparing an autoclaved aerated concrete block is provided, which comprises, in terms of dry basis mass percentage, 70-80% of fly ash acid method aluminum extraction residue, 2-3% of power plant desulfurization gypsum, 6-13% of cement, and 12-20% of quicklime; wherein 90% of the fly ash acid method aluminum extraction residue has a particle size of ≤75μm.

[0019] By using the fly ash acid method aluminum extraction residue as raw material, and by using the characteristics that the fly ash acid method aluminum extraction residue has a porous structure and a large specific surface area, and is easy to have a hydration reaction with cement and quicklime, the dry density of the block can be reduced, the compressive strength of the autoclaved aerated concrete block can be improved, and thus the autoclaved aerated concrete block obtained finally has excellent mechanical strength and low dry density. Meanwhile, the resource utilization of industrial solid waste residue is realized, environmental pollution is reduced, and engineering quality is improved.

[0020] In some embodiments of the present application, the fly ash acid aluminum extraction residue contains, in terms of dry mass, SiO2>55%, Al2O3<24%, the total mass of SiO2 and Al2O3>75%, CaO<1%, MgO<1%, and loss on ignition<13%. The above components are more conducive to the hydration reaction of the fly ash acid aluminum extraction residue with cement and quicklime.

[0021] In an embodiment of the present application, 90% of the fly ash acid aluminum extraction residue has a particle size of ≤75 μm, and preferably 90% of the fly ash acid aluminum extraction residue has a particle size of 40-75 μm. Preferably, the specific surface area of the fly ash acid aluminum extraction residue is 60-100 m2 / g. 2

[0022] The fly ash acid aluminum extraction residue with the above particle size characteristics and specific surface area is preferably conducive to the hydration reaction of the fly ash acid aluminum extraction residue with cement and quicklime, thereby better reducing the dry density of autoclaved aerated concrete blocks and improving the compressive strength of the autoclaved aerated concrete blocks.

[0023] In an embodiment of the present application, the fly ash acid aluminum extraction residue has an average true density of 1.3-2.35 g / cm3, and preferably a bulk density of 0.4-0.6 g / cm3. 3 3

[0024] The fly ash acid aluminum extraction residue with the above true density and bulk density is preferably conducive to better reducing the dry density of autoclaved aerated concrete blocks, thereby improving the compressive strength of the autoclaved aerated concrete blocks.

[0025] In an embodiment of the present application, the above raw material composition further includes a gas-forming agent, and the gas-forming agent is preferably aluminum paste. The mass of the aluminum paste is preferably 0.062-0.075% of the total mass of the fly ash acid aluminum extraction residue, the power plant desulfurization gypsum, the cement, and the quicklime, and the effective Al content of the aluminum paste is preferably ≥90%, and the particle size of the aluminum paste is preferably ≤75 μm.

[0026] The aluminum paste with the above content is preferably more conducive to the synergistic effect with other components in the raw material composition, thereby forming more fine bubbles in the autoclaved aerated concrete blocks and uniformly distributing the bubbles in the autoclaved aerated concrete blocks, thereby reducing the density of the autoclaved aerated concrete blocks and improving the thermal insulation performance and the impermeability of the autoclaved aerated concrete blocks. Further preferably, the aluminum paste is GLS-65 special water-based paste.

[0027] In an embodiment of the present application, the above power plant desulfurization gypsum has a water content of ≤16%, and the content of CaSO4·2H2O in the power plant desulfurization gypsum is preferably ≥85%.​​​

[0028] The power plant desulfurization gypsum is preferably used as a raw material for preparing the autoclaved aerated concrete block, which helps to improve the strength and durability of the autoclaved aerated concrete block, and the power plant desulfurization gypsum does not have any adverse effect on the autoclaved aerated concrete block over time.

[0029] The raw material for preparing the autoclaved aerated concrete block can be sourced from a wider range, and in some embodiments of the present application, the cement is preferably 525 cement, 425 cement or 325 cement.

[0030] In an embodiment of the present application, the effective CaO content of the quicklime is ≥ 85%, and the content of MgCO3 in the quicklime is ≤ 12%; preferably, the particle size of the quicklime is 40-75 μm.

[0031] The preferred quicklime helps to improve the fluidity of the raw material mixture, increase the water retention and cohesiveness thereof. However, the use of the quicklime to completely replace the cement in the required amount can result in insufficient strength of the autoclaved aerated concrete block, and the mass ratio of the cement to the quicklime is preferably 1:2, which helps to improve the synergistic effect of the cement and the quicklime, and finally obtain autoclaved aerated concrete blocks with better comprehensive performance.

[0032] In another typical embodiment of the present application, an autoclaved aerated concrete block is provided, which is prepared from a mixture of a raw material composition.

[0033] The autoclaved aerated concrete block prepared from the raw material composition has a porous structure and a large specific surface area, and is easy to have a hydration reaction with the cement and the quicklime, which can better reduce the dry density of the block, and is beneficial to improve the compressive strength of the autoclaved aerated concrete block, so that the autoclaved aerated concrete block finally obtained has excellent mechanical strength and low dry density. At the same time, the industrial solid waste residue is utilized as a resource, the environmental pollution is reduced, and the engineering quality is improved.

[0034] In another typical embodiment of the present application, a preparation method of the autoclaved aerated concrete block is provided, which comprises the following steps: S1, mixing raw materials including the fly ash acid aluminum extraction residue, the power plant desulfurization gypsum, the cement, the quicklime and water to obtain a mixed slurry; and S2, successively pouring, gas-forming molding, cutting and autoclaving and curing the mixed slurry to obtain the autoclaved aerated concrete block.

[0035] The step S1 makes the components be uniformly mixed, the step S2 pours, foaming forming, cutting and autoclaving the mixed slurry, so that the raw materials are fully hydrothermally reacted, and after a series of physical and chemical reactions, the autoclaved aerated concrete block finally obtained has excellent mechanical strength and low dry density. Meanwhile, the industrial solid waste residue is recycled, the environmental pollution is reduced, and the engineering quality is improved.

[0036] In an embodiment of the present application, the autoclaving conditions include: performing vacuumizing operation under the condition that the temperature in the kettle is 50-60℃, so that the vacuum degree is 0.03-0.06MPa, and the vacuumizing time is 30-60min; and then performing stepwise temperature rising and pressure increasing operation.

[0037] The wet heat environment provided by the autoclaving conditions above helps the raw materials in the block to be fully hydrothermally reacted, so that the autoclaved aerated concrete block finally obtained has excellent strength. Specifically, the mixed slurry is quickly poured into the mold, and is statically stopped in the oven at 45-50℃ for 120-150min, and the bread head is cut off and the mold is removed; this step can be performed when the green body has appropriate hardness, so as to better ensure the integrity of the green body.

[0038] In an embodiment of the present application, the stepwise temperature rising and pressure increasing operation process includes: sequentially maintaining at 60-70℃ for 45-60min, at 75-85℃ for 10-30min, at 130-145℃ for 10-30min, and at 175-188℃ for 420-480min.

[0039] The autoclaving conditions above preferably have stepwise temperature rising, which effectively avoids the cracking phenomenon of the formed autoclaved aerated concrete block, and after the stepwise temperature rising and pressure increasing operation program is completed, the kettle is naturally cooled to 40℃, the remaining gas is discharged, and the kettle is opened.

[0040] The beneficial effects of the present application will be further illustrated by the following embodiments.

[0041] The raw materials used in the following embodiments have the following characteristics:

[0042] The chemical composition of the fly ash acid aluminum extraction residue is shown in the following table:

[0043] Fly ash acid aluminum extraction residue composition table

[0044] Component SiO2 Al2O3 MgO CaO Fe2O3 Na2O K2O TiO2 Loss on ignition wt% 55.84 23.01 0.03 0.30 0.74 2.99 0.34 4.17 12.54

[0045] The specific surface area of the fly ash acid aluminum extraction residue is 72m 2 / g, and the 90% particle size is 75μm; the average value of the true density is 1.9g / cm 3Bulk density: 0.4 g / cm 3 ;

[0046] FGD gypsum: FGD gypsum from a power plant; Conditioned moisture content: 15%, CaSO4-2H2O content: 86%;

[0047] 425 cement: 425 cement from a certain market;

[0048] Quicklime: 90 quicklime from a certain market.

[0049] Example 1

[0050] 1.1 Raw material ratio:

[0051] Raw material ratio table of Example 1

[0052]

[0053] 1.2 Preparation method

[0054] (1) The fly ash acid aluminum extraction residue was dried at 110°C for 48h, and then crushed by a micro-pulverizer; (2) The dried 74% fly ash acid aluminum extraction residue and 3% FGD gypsum were weighed and mixed, and then stirred at low speed for 1 min; 7% cement and 16% quicklime powder were weighed and mixed, and then stirred at low speed for 4 min; (3) 32-38°C tap water was weighed (1 / 6-1 / 7 of the water was taken out for standby), and then added to (2) and stirred slowly for 20s, and then stirred quickly for 220s; the standby tap water was used in 4 times, and the first time of water was added to the aluminum powder, and then homogenized by a high-speed homogenizer for 5s to prepare an aluminum powder suspension, and then the aluminum powder suspension (the remaining water was washed for 3 times) was poured into the stirring pot, and then stirred slowly for 8s, and then stirred quickly for 40s to prepare a slurry; (5) The slurry was quickly poured into a mold, and then placed in a 45°C oven for 150 min, and then the bread head was cut off by a steel wire and the mold was removed; (6) The wet body prepared in (5) was placed in a steam pressure curing kettle for steam pressure curing; the steam pressure curing system was as follows: after the temperature in the kettle was raised to 60°C, the vacuum was extracted for 60 min, the vacuum condition was 0.05 MPa, the temperature was kept at 70°C for 60 min, 85°C for 30 min, 145°C for 30 min, and 188°C for 480 min, and then the temperature was naturally reduced to 40°C, and then the exhaust was opened; the kettle was placed in an oven at 45°C for 5 days; (7) Three 100mmx100mmx100mm cubic test pieces were formed for each group, and then the compressive strength and dry density were tested. The compressive strength of the sample after the kettle was taken out was 5.2 MPa, and the dry density was 610 Kg / m 3 .

[0055] Example 2

[0056] 2.1 Raw material ratio

[0057] Raw material ratio table of Example 2

[0058] Name Acid fly ash residue Gypsum Cement Quicklime Total Water / solid wt% of Al powder wt% 72 3 8 17 100 0.85 0.065

[0059] 2.2 Preparation method

[0060] (1) The fly ash acid aluminum extraction residue was dried at 110°C for 48h, and then crushed by a micro-pulverizer; (2) The dried 72% fly ash acid aluminum extraction residue and 3% power plant desulfurization gypsum were mixed by proportion, and then stirred at low speed for 1min; 8% cement and 17% quicklime powder were mixed by proportion, and then stirred at low speed for 4min; (3) 0.85 water / material was weighed, and then the tap water at 32-38°C was added into (2) and stirred at low speed for 20s, and then stirred at high speed for 220s; the tap water was used in 4 times, and the first time water was added into the aluminum powder, and then the homogenizer was used to homogenize for 5s to obtain the aluminum powder suspension, and then the aluminum powder suspension was poured into the stirring pot, and stirred at low speed for 8s, and then stirred at high speed for 40s to obtain the slurry; (5) The slurry was quickly poured into the mold, and then the wet blank was placed in the steam pressure curing kettle for steam pressure curing; the steam pressure curing system was as follows: after the temperature in the kettle was increased to 60°C, the vacuum was extracted for 60min, and then the vacuum condition was 0.06MPa, and then the temperature was kept at 70°C for 60min, 85°C for 30min, 145°C for 30min, and 188°C for 480min, and then the temperature was naturally decreased to 40°C, and then the kettle was opened; the wet blank was placed in the oven at 45°C for 5 days; (7) Three 100mmx100mmx100mm cubic test pieces were formed in each group, and then the compressive strength and dry density were tested. The compressive strength of the sample after the kettle was opened was 5.53MPa, and the dry density was 615Kg / m 3 .

[0061] Example 3

[0062] 3.1 Raw material ratio

[0063] Raw material ratio table of Example 3

[0064] Component Acid fly ash residue Gypsum Cement Quicklime Total Water / solid wt% of Al powder wt% 70 3 9.5 18 100 0.85 0.065

[0065] 3.2 Preparation method

[0066] (1) The fly ash acid method aluminum extraction residue is dried at 110°C for 48h, and then crushed by a micro-pulverizer; (2) The dried fly ash (70%) and desulfurization gypsum (2.5%) are weighed and mixed, and then stirred at low speed for 1min; the cement (9.5%) and lime powder (18%) are weighed and mixed, and then stirred at low speed for 4min; (3) The tap water (32-38°C) is weighed according to the ratio of 0.85 water / material, and then added to (2) and stirred at low speed for 20s, and then stirred at high speed for 220s; the tap water is divided into four portions, and the first portion is added to the aluminum powder, and then homogenized by a high-speed homogenizer for 5s to obtain an aluminum powder suspension, and the aluminum powder suspension is poured into the stirring pot, and then stirred at low speed for 8s, and then stirred at high speed for 40s to obtain a slurry; (5) The slurry is quickly poured into a mold, and then placed in an oven at 45°C for 150min, and then the bread head is cut off and the mold is removed; (6) The wet block obtained in (5) is placed in a steam pressure curing kettle for steam pressure curing; the steam pressure curing system is as follows: after the temperature in the kettle rises to 60°C, vacuum is applied for 60min, the vacuum condition is 0.03MPa, the temperature is kept at 70°C for 60min, 85°C for 30min, 145°C for 30min, and 188°C for 480min, and then the temperature is naturally reduced to 40°C, the exhaust is opened, and the kettle is opened; the kettle is placed in an oven at 45°C for 5 days; (7) Three 100mm×100mm×100mm cubic test pieces are formed for each group, and the compressive strength and dry density are tested. The compressive strength of the sample after being taken out of the kettle is 5.5MPa, and the dry density is 625Kg / m 3 .

[0067] Example 4

[0068] The difference from Example 1 is that,

[0069]

[0070] The autoclaved aerated concrete block is finally obtained.

[0071] Example 5

[0072] The difference from Example 1 is that,

[0073]

[0074] The autoclaved aerated concrete block is finally obtained.

[0075] Example 6

[0076] The difference from Example 1 is that,

[0077] Composition table of fly ash acid method aluminum extraction residue

[0078] Component SiO2 Al2O3 MgO CaO Fe2O3 Na2O [K2O] TiO2 Loss on ignition wt% 56 20 0.03 0.30 0.74 2.99 0.34 4.17 15.43

[0079] Autoclaved aerated concrete block was finally obtained.

[0080] Example 7

[0081] The difference from Example 1 is that 90% of the particle size of the fly ash acid aluminum extraction residue is 40 μm, and autoclaved aerated concrete block is finally obtained.

[0082] Example 8

[0083] The difference from Example 1 is that 90% of the particle size of the fly ash acid aluminum extraction residue is 95 μm, and autoclaved aerated concrete block is finally obtained.

[0084] Example 9

[0085] The difference from Example 1 is that 80% of the particle size of the fly ash acid aluminum extraction residue is 75 μm, and autoclaved aerated concrete block is finally obtained.

[0086] Comparative Example 1

[0087] The difference from Example 1 is that the fly ash acid aluminum extraction residue is replaced by fly ash.

[0088] 4.1 Raw material ratio

[0089] Raw material ratio table of Comparative Example 1

[0090] Component Fly ash Gypsum Cement Quicklime Total Water / solid wt% of Al powder wt% 74 3 7 16 100 0.85 0.065

[0091] Fly ash composition table of Comparative Example 1

[0092] Component SiO2 Al2O3 MgO CaO K2O Na2O TiO2 P2O5 Fe2O3 wt% 45.36 38.49 0.11 0.16 0.40 0.08 0.44 0.04 0.32

[0093] 4.2 Preparation method

[0094] (1)Fly ash was dried at 110°C for 48h, and then ground by a micro grinder; (2) 74% of the dried fly ash and 3% of the desulfurization gypsum were mixed by weight, and then stirred at low speed for 1 min; 7% of cement and 16% of lime powder were mixed by weight, and then stirred at low speed for 4 min; (3) 0.85 water / material was weighed, and then 32-38°C tap water was added into (2) and stirred at low speed for 20 s, and then stirred at high speed for 220 s; the remaining tap water was used for 4 times, and the first time of the tap water was added into the aluminum powder, and then the aluminum powder suspension was prepared by using a high-speed homogenizer for 5 s, and then the aluminum powder suspension was poured into the stirring pot and stirred at low speed for 8 s, and then stirred at high speed for 40 s; (5) the slurry was poured into a mold at high speed, and then the wet sample was placed in a steam pressure curing kettle for steam pressure curing; the steam pressure curing system was as follows: when the temperature in the kettle reached 60°C, the kettle was vacuumized for 60 min, and then the temperature was kept at 70°C for 60 min, at 85°C for 30 min, at 145°C for 30 min, and at 188°C for 480 min; after the temperature was naturally reduced to 40°C, the kettle was opened; the wet sample was placed in an oven at 45°C for 5 days; (6) three 100mmx100mmx100mm cubic samples were formed in each group, and then the compressive strength and dry density were tested; the compressive strength of the sample was 3.2MPa, and the dry density was 630Kg / m 3 .

[0095] Comparative Example 2

[0096] The difference between Comparative Example 1 and Comparative Example 2 is that,

[0097] 5.1 Raw material ratio

[0098] Raw material ratio table of Comparative Example 2

[0099] Name Fly ash Gypsum Cement Quicklime Total Water / solid wt% of Al powder wt% 70 3 9.5 18 100 0.85 0.065

[0100] 4.2 Preparation method

[0101] (1) The fly ash was dried at 110°C for 48h, and then crushed by a micro grinder for standby; (2) 70% of the dried fly ash and 3% of the desulfurization gypsum from the power plant were weighed and mixed, and then stirred at low speed for 1min; 9.5% of cement and 18% of lime powder were weighed and mixed, and then stirred at low speed for 4min; (3) 0.85 water / material was weighed, and 32-38°C tap water was weighed (1 / 6-1 / 7 of the water was taken out for standby), and then the weighed water was added to (2) and stirred at low speed for 20s, and then stirred at high speed for 220s; the standby tap water was used in 4 times, and the first time water was added to the aluminum powder, and then a high-speed homogenizer was used to homogenize for 5s to prepare an aluminum powder suspension, and the aluminum powder suspension (at the same time, the remaining water was washed for 3 times) was poured into the stirring pot, and then stirred at low speed for 8s, and then stirred at high speed for 40s to prepare a slurry; (5) the slurry was quickly poured into a mold, and then placed in a 45°C oven for 150min, and then the bread head was cut off and the mold was removed; (6) the wet block prepared in (5) was placed in a steam pressure curing kettle for steam pressure curing. The steam pressure curing system was as follows: after the temperature in the kettle was raised to 60°C, vacuum was applied for 60min, the vacuum condition was 0.03-0.06MPa, 70°C was maintained for 60min, 85°C was maintained for 30min, 145°C was maintained for 30min, 188°C was maintained for 480min, and then the temperature was naturally lowered to 40°C, and then the exhaust was opened; the kettle was placed in an oven at 45°C for 5 days; (7) three 100mm×100mm×100mm cubic test pieces were formed for each group, and the compressive strength and dry density were tested. The compressive strength of the sample out of the kettle was 3.6MPa, and the dry density was 645Kg / m 3 .

[0102] Comparative Example 3

[0103] The difference from Example 1 is that,

[0104]

[0105] Finally, the autoclaved aerated concrete block was obtained.

[0106] The compressive strength and dry density of the autoclaved aerated concrete blocks obtained in Examples 1-9 and Comparative Examples 1-3 were detected by the method of Autoclaved Aerated Concrete Block (GB / T 11968-2020), and the test results are shown in the following table:

[0107]

[0108]

[0109] From the data in the compressive strength and dry density test result table, compared with the autoclaved aerated concrete blocks obtained in other examples, the compressive strength of the autoclaved aerated concrete block obtained in Comparative Example 1 is reduced by about 38% when the fly ash aluminum extraction residue is changed into fly ash, and the dry density changes little; the compressive strength of the autoclaved aerated concrete block obtained in Comparative Example 2 is also reduced by about 38% when the fly ash aluminum extraction residue is changed into fly ash, and the dry density changes little.

[0110] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

[0111] Using fly ash acid method aluminum extraction residue as raw material, taking advantage of its porous structure and large specific surface area, and the characteristics of easy hydration reaction with cement and quicklime, the dry density of the block can be reduced, which is beneficial to improve the compressive strength of the autoclaved aerated concrete block, so that the autoclaved aerated concrete block obtained finally has excellent mechanical strength and low dry density. At the same time, the resource utilization of industrial solid waste residue is realized, the environmental pollution is reduced, and the engineering quality is improved.

[0112] The above is only the preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A raw material composition for preparing autoclaved aerated concrete blocks, characterized in that, The raw material composition consists of the following ingredients in terms of dry basis mass percentage: 70-80% fly ash acid aluminum extraction residue; 2-3% power plant desulfurization gypsum; 6-13% cement; 12-20% quicklime; and an air-entraining agent; The fly ash acid aluminum extraction residue contains SiO2 in a mass of >55%, Al2O3 in a mass of <24%, a total mass of SiO2 and Al2O3 of >75%, CaO in a mass of <1%, MgO in a mass of <1%, and a mass of loss on ignition of <13%, in terms of dry basis mass of the fly ash acid aluminum extraction residue. The fly ash acid aluminum extraction residue has 90% of particle size of 40-75 μm; the specific surface area of the fly ash acid aluminum extraction residue is 60-100 m 2 / g. The average value of the true density of the fly ash acid aluminum extraction residue is 1.3-2.35 g / cm 3 The bulk density of the fly ash acid aluminum extraction residue is 0.4-0.6 g / cm 3 ; The power plant desulfurization gypsum has a water content of ≤16% and a CaSO4·2H2O content of ≥85%.

2. The feedstock composition of claim 1, wherein The air-entraining agent is aluminum powder paste, and the mass of the aluminum powder paste is 0.062-0.075% of the total mass of the fly ash acid aluminum extraction residue, the power plant desulfurization gypsum, the cement, and the quicklime.

3. The feedstock composition of claim 2, wherein The effective Al content of the aluminum powder paste is ≥90%.

4. The feedstock composition of claim 2, wherein The particle size of the aluminum powder paste is ≤75 μm.

5. The feedstock composition of claim 1, wherein The cement is 525 cement, 425 cement, or 325 cement.

6. The feedstock composition of claim 1, wherein The effective CaO content of the quicklime is ≥85%, and the MgCO3 content of the quicklime is ≤12%.

7. The feedstock composition of claim 1, wherein The particle size of the quicklime is 40-75 μm.

8. An autoclaved aerated concrete block prepared from a composition by mixing, characterized in that, The composition is the raw material composition of any one of claims 1-7.

9. A method of producing the autoclaved aerated concrete block according to claim 8, characterized in that, The preparation method comprises: S1. mixing raw materials including fly ash acid aluminum extraction residue, power plant desulfurization gypsum, cement, quicklime, and water to obtain a mixed slurry; S2. sequentially performing casting, air-entraining forming, cutting, and autoclave curing on the mixed slurry to obtain the autoclaved aerated concrete block.

10. The method of claim 9, wherein, The autoclave curing conditions comprise: performing a vacuumizing operation at a kettle temperature of 50-60 ℃ to obtain a vacuum degree of -0.03 to -0.06 MPa and a vacuumizing time of 30-60 min; and then performing a stepwise temperature increasing and pressure increasing operation.

11. The method of claim 10, wherein, The stepwise temperature increasing and pressure increasing operation comprises: sequentially maintaining at 60-70 ℃ for 45-60 min, at 75-85 ℃ for 10-30 min, at 130-145 ℃ for 10-30 min, and at 175-188 ℃ for 420-480 min.

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