A gas-liquid-solid three-phase stable bubble agent and high-strength autoclaved aerated concrete plate

Abstract

The application discloses a gas-liquid-solid three-phase foam stabilizer and a high-strength autoclaved aerated concrete plate, and belongs to the technical field of building material preparation. The three-phase foam stabilizer is an aqueous solution containing long-alkyl-chain anion compound modified layered double hydroxide and surfactant, and the mass ratio of the long-alkyl-chain anion compound modified layered double hydroxide to the surfactant is 1:5-1:10. The high-strength autoclaved aerated concrete plate prepared by using the three-phase foam stabilizer as a foam stabilizer forms a gas-liquid-solid three-phase after foaming. The solid nanosheet modified by the long-carbon-chain organic matter can exist on the surface of the foam, and exists on the gas-liquid interface generated in the foaming process of the aerated concrete to play a role of a crystal nucleus. The solid nanosheet participates in the reaction on the interface to generate a hydration product which can improve the strength of the gas-solid interface in the aerated concrete, so that higher strength is provided for the product.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building material preparation, and relates to a gas-liquid-solid three-phase foam stabilizer for preparing high-strength aerated concrete. BACKGROUND

[0002] Autoclaved aerated concrete board is a new type of light and porous building material which is prepared by using cement, fly ash, lime, etc. as main raw materials and adding different amounts of anti-corrosion treated According to structural requirements. The autoclaved aerated concrete board is produced by high-temperature and high-pressure reaction and has porous crystals. The density of the autoclaved aerated concrete board is smaller than that of general cement materials, and the autoclaved aerated concrete board has incomparable properties such as fire resistance, fire prevention, sound insulation, heat insulation, and heat preservation. The autoclaved aerated concrete board can replace traditional aerated concrete blocks and cement slag hollow wall boards. In addition to greatly reducing engineering time, improving engineering installation quality, and reducing building cost, the autoclaved aerated concrete board can also achieve the purposes of protecting the environment, saving energy, improving wall surface quality, increasing building aesthetics, and improving indoor environmental comfort. However, due to the porous structure of the product, the products in the industry generally have poor impact resistance and low compressive strength. This characteristic leads to a high breakage rate during the board breaking process and subsequent transportation. In order to improve the performance of the product, a foam stabilizer is usually used in the production process of the aerated concrete board. The main purpose of the foam stabilizer is to make the bubbles more uniform, reduce the stringing hole, and make the product have a uniform pore size, so as to increase the mechanical strength of the aerated concrete board to a certain extent.

[0003] The traditional foam stabilizer is usually a surfactant. It can reduce the surface tension of the bubbles, enhance the stability of the bubbles, prolong the residence time, and finally make the concrete have a better pore structure, thereby improving the compressive strength and impact resistance of the product to a certain extent. However, it is very limited to rely only on this type of foam stabilizer to improve the strength of the product. Therefore, it is necessary to design a gas-liquid-solid three-phase foam stabilizer with excellent performance. The gas-liquid-solid three-phase foam stabilizer can not only be beneficial to the formation of closed pores with appropriate and uniform pore size in the aerated concrete, but also can generate more crystal products on the foam interface during the foaming process of the aerated concrete.

[0004] In order to achieve the above-mentioned purpose, the gas-liquid-solid three-phase foam stabilizer relates to a water solution of long alkyl chain anion compound modified layered double hydroxide and surfactant, and the mass ratio of long alkyl chain anion compound modified layered double hydroxide and surfactant is 1:5-1:10 according to the mass of long alkyl chain anion compound modified layered double hydroxide after drying.

[0005] The gas-liquid-solid three-phase foam stabilizer prepared by the method can provide crystal nucleus in the process of gas evolution, increase the hydration product of gas-solid interface in the process of steam curing, and thus improve the strength of aerated concrete.

[0006] The preparation method of the gas-liquid-solid three-phase foam stabilizer comprises the following steps:

[0007] (1) dispersing 10-20 g of layered double hydroxide precipitate in 20 ml of 0.005-0.1 mol / l long alkyl chain anion compound solution to obtain a uniformly dispersed suspension;

[0008] (2) mixing 20 ml of the above suspension with 3-7 ml of surfactant, and fully mixing to obtain the gas-liquid-solid three-phase foam stabilizer.

[0009] Further, the layered double hydroxide in step (1) is prepared by a traditional coprecipitation method or a microchannel reactor method, and the microchannel reactor method is preferred.

[0010] Further, the reaction temperature of the traditional coprecipitation method or the microchannel reactor method is 30-50°C, and the reaction time is 0.5-2 hours.

[0011] 10-20 g of layered double hydroxide precipitate is dispersed in 20 ml of 0.005-0.1 mol / l long alkyl chain anion compound solution, and the ultrasonic dispersion time is 5-15 min and the temperature is 25-35 o C.

[0012] Further, the layered double hydroxide precipitate has a general formula of [M 2+ 1-x M 3+ x (OH)2] x+ (A n- ) x / n ·yH2O, wherein M2+ is any one or two of the divalent metal ions Mg 2+ , Ca 2+ , Zn 2+ ; M 3+ is Al 3+ or Fe 3 + ; A n- is any one of the ions NO3 - , CO3 2- or Cl - ; 0.17≤x≤0.35; 0≤y≤2.

[0013] Further, the long alkyl chain anion compound is C n-1 H 2n-1 XOO - M + , n=11-22, X represents chemical elements C, S, P, M + represents monovalent metal ions K + , Na + , specifically: sodium (potassium) laurate, sodium (potassium) stearate, sodium (potassium) palmitate.

[0014] Further, the mass ratio of the long alkyl chain anion compound to the layered double hydroxide is 1:5~1:60, calculated on the basis of the mass of the dried layered double hydroxide. Further, the mass ratio of the long alkyl chain anion compound modified layered double hydroxide to the surfactant is 1:5-1:10, calculated on the basis of the mass of the dried long alkyl chain anion compound modified layered double hydroxide.

[0015] Further, the surfactant is one or more of coconut diethanolamide, disodium lauroamphodipropyl sulfonate, cocamidopropyl hydroxysultaine, disodium lauryl citrate sulfosuccinate, disodium lauryl ether sulfosuccinate, sodium fatty alcohol polyethyleneglycol ether carboxylate, oleic diethanolamide, disodium lauryl sulfosuccinate, disodium lauroamphoacetate, sodium lauroyl sarcosinate, sodium lauroyl glutamate.

[0016] A preparation method of autoclaved high-strength aerated concrete plate, specifically:

[0017] (1) 10 parts of water-washed sand, 0.8-1.2 parts of gypsum, 9-11 parts of water are mixed to form a slurry, and then mixed with 2-2.6 parts of cement, 1.8-2.2 parts of quicklime, 2.5-3 parts of fly ash, 1.2-1.8 parts of water to obtain a high-strength aerated concrete slurry;

[0018] (2) A certain amount of aluminum powder for foaming is dispersed in the gas-liquid-solid three-phase foam stabilizer, wherein the mass of the aluminum powder and the gas-liquid-solid three-phase foam stabilizer is 0.07-0.10% and 0.20-0.3% of the mass of the solid powder in step (1) respectively, and after being uniformly stirred, the mixture is directly poured into the high-strength aerated concrete slurry, is rapidly stirred in a cement paste stirrer for 45s and then slowly stirred for 30s, and then the slurry is rapidly poured into a test mold and placed in a constant temperature and humidity standard curing box at 45°C for curing, and the slurry is allowed to stand for 4 hours after foaming; the test block after standing and curing is removed from the mold and is placed in a steam autoclave at a saturated steam pressure of 1.5 MPa and a high temperature of 190°C for high temperature and high pressure curing.

[0019] Different from the conventional foam stabilizer, the gas-liquid-solid three-phase foam stabilizer is mainly composed of a surfactant, a surface-modified nanosheet and water, and after foaming, a gas-liquid-solid three-phase is formed, the solid nanosheet modified by a long carbon chain organic matter can exist on the surface of the foam, plays a role of a crystal nucleus on the gas-liquid interface generated during the foaming of the aerated concrete, participates in the reaction on the interface, and generates a hydration product which can improve the strength on the gas-solid interface in the aerated concrete, thereby providing higher strength for the product.

[0020] Compared with the prior art, the present application has the following advantages: (1) the gas-liquid-solid three-phase foam stabilizer is composed of a surface-modified layered double hydroxide nanosheet, a surfactant and water, the nanosheet has an ultrathin sheet structure and a lateral size of 20-30nm, provides a crystal nucleus for the hydration of the aerated concrete, and promotes the generation of a hydration product; (2) the surface of the nanosheet is modified by an anionic surfactant, and has good compatibility with the foaming agent; (3) the only solvent used in the preparation process is water, and the process is environmentally friendly. DETAILED DESCRIPTION

[0021] The present application will be further described below by way of examples.

[0022] Example 1

[0023] The specific process steps of the present example are as follows:

[0024] (1) Zn(NO3)2 and Al(NO3)3 are dissolved in 50ml deionized water to prepare a mixed salt solution with a total metal ion concentration of 0.3mol / l; the amount-of-substance ratio of Zn to Al is 2:1; 50ml of an ammonia water solution with a mass concentration of 7% is prepared;

[0025] (2) the mixed salt solution and the ammonia water solution are mixed and reacted by using a T-shaped microreactor method, and the obtained layered double hydroxide suspension is fully stirred for 30min at 25 o C;

[0026] (3) Centrifuge the layered double hydroxide suspension prepared in step (2) and wash with deionized water to obtain layered double hydroxide precipitate, take 10 g of the layered double hydroxide precipitate and disperse in 20 ml of potassium laurate solution with a concentration of 20 mmol / l, fully stir at 30 o C for 2 hours to obtain a uniformly dispersed suspension;

[0027] (4) Mix the product prepared in step (3) with 5 g of coconut oil acid diethanolamide to prepare a gas-liquid-solid three-phase foam stabilizer.

[0028] Example 2:

[0029] The specific process steps of this example are as follows:

[0030] (1) Dissolve Mg(NO3)2 and Al(NO3)3 in 50 ml of deionized water to prepare a mixed salt solution with a total metal ion concentration of 0.3 mol / l; the molar ratio of Mg to Al is 2:1; prepare 50 ml of ammonia solution with a mass concentration of 7%;

[0031] (2) Mix the above mixed salt solution and ammonia solution using a T-shaped microreactor method and allow the reaction to occur, obtain a layered double hydroxide suspension, fully stir the suspension at 25 o C for 30 min;

[0032] (3) Centrifuge the layered double hydroxide suspension prepared in step (2) and wash with deionized water to obtain layered double hydroxide precipitate, take 10 g of the layered double hydroxide precipitate and disperse in 20 ml of potassium laurate solution with a concentration of 20 mmol / l, fully stir at 30 o C for 2 hours to obtain a uniformly dispersed suspension;

[0033] (4) Mix the product prepared in step (3) with 5 g of coconut oil acid diethanolamide to prepare a gas-liquid-solid three-phase foam stabilizer.

[0034] Example 3:

[0035] The specific process steps of this example are as follows:

[0036] (1) Dissolve Ca(NO3)2 and Al(NO3)3 in 50 ml of deionized water to prepare a mixed salt solution with a total metal ion concentration of 0.3 mol / l; the molar ratio of Ca to Al is 2:1; prepare 50 ml of ammonia solution with a mass concentration of 7%;

[0037] (2) Mix the above mixed salt solution and ammonia solution using a T-shaped microreactor method and allow the reaction to occur, obtain a layered double hydroxide suspension, fully stir the suspension at 25o C for 30 min with sufficient stirring;

[0038] (3) The layered double hydroxide suspension prepared in step (2) was centrifuged and washed with deionized water to obtain a layered double hydroxide precipitate. 10 g of the layered double hydroxide precipitate was dispersed in 20 ml of a potassium laurate solution with a concentration of 20 mmol / l, and the mixture was stirred at 30 o C for 2 hours with sufficient stirring to obtain a uniformly dispersed suspension;

[0039] (4) The product prepared in step (3) was mixed with 5 g of cocamide MEA to prepare a gas-liquid-solid three-phase foam stabilizer.

[0040] Example 4:

[0041] The specific process steps of this example are as follows:

[0042] (1) Mg(NO3)2 and Al(NO3)3 were dissolved in 50 ml of deionized water to prepare a mixed salt solution with a total metal ion concentration of 0.3 mol / l. The molar ratio of Mg to Al was 2:1. 50 ml of an ammonia solution with a mass concentration of 7% was prepared;

[0043] (2) The mixed salt solution and the ammonia solution were mixed and reacted using a T-shaped microreactor method to obtain a layered double hydroxide suspension. The suspension was stirred at 25 o C for 30 min with sufficient stirring;

[0044] (3) The layered double hydroxide suspension prepared in step (2) was centrifuged and washed with deionized water to obtain a layered double hydroxide precipitate. 10 g of the layered double hydroxide precipitate was dispersed in 20 ml of a potassium laurate solution with a concentration of 20 mmol / l, and the mixture was stirred at 30 o C for 2 hours with sufficient stirring to obtain a uniformly dispersed suspension;

[0045] (4) The product prepared in step (3) was mixed with 2.5 g of cocamide MEA and 2.5 g of cocamide DEA to prepare a gas-liquid-solid three-phase foam stabilizer.

[0046] Example 5:

[0047] The specific process steps of this example are as follows:

[0048] (1) Mg(NO3)2 and Al(NO3)3 were dissolved in 50 ml of deionized water to prepare a mixed salt solution with a total metal ion concentration of 0.3 mol / l. The molar ratio of Mg to Al was 2:1. 50 ml of an ammonia solution with a mass concentration of 7% was prepared;

[0049] (2) The mixed salt solution is mixed with ammonia solution by using T-type micro-reactor method and reacts to obtain a layered double hydroxide suspension, which is fully stirred at 25 o C for 30 min;

[0050] (3) The layered double hydroxide suspension prepared in step (2) is centrifuged and washed with deionized water to obtain a layered double hydroxide precipitate, 10 g of which is dispersed in 20 ml of a potassium laurate solution with a concentration of 20 mmol / l, and fully stirred at 30 o C for 2 hours to obtain a uniformly dispersed suspension;

[0051] (4) The product prepared in step (3) is mixed with 5 g of lauryl alcohol ether sulfosuccinic acid monoester disodium salt to prepare a gas-liquid-solid three-phase foam stabilizer.

[0052] Application example:

[0053] A preparation method of autoclaved high-strength aerated concrete board, specifically comprising:

[0054] (1) 10 parts of water-washed sand, 1 part of gypsum, and 10 parts of water are mixed to form a slurry, and then mixed with 2.3 parts of cement, 2 parts of quicklime, 2.7 parts of fly ash, and 1.5 parts of water to obtain a high-strength aerated concrete slurry;

[0055] (2) A certain amount of aluminum powder is dispersed in the gas-liquid-solid three-phase foam stabilizer prepared in Example 1-5, wherein the mass of the aluminum powder and the gas-liquid-solid three-phase foam stabilizer is 0.08% and 0.25% of the mass of the solid powder in step (1) respectively, and after being uniformly stirred, it is directly poured into the high-strength aerated concrete slurry, and then stirred in a cement paste stirrer at a fast speed for 45 s and at a slow speed for 30 s, and then the slurry is quickly poured into a test mold and placed in a constant temperature and humidity standard curing box at 45°C for curing, and the test block is cured for 4 hours, and then the test block is removed from the mold and placed in an autoclave with a saturated steam pressure of 1.5 MPa and a high temperature of 190°C for high temperature and high pressure curing. Then the autoclaved test block is taken out and tested for compressive strength, and the results are shown in Table 1. It can be seen that the gas-liquid-solid three-phase foam stabilizer mixed with the layered double hydroxide modified by the long-chain anionic compound and the surfactant can further enhance the compressive strength and impact resistance of the test block based on Comparative Example 2, because the gas-liquid-solid three-phase foam stabilizer can increase the production of hydration products in the solid layer between the bubbles, thereby improving the overall strength of the product.

[0056] Comparative Example 1:

[0057] The specific process steps of this comparative example are as follows:

[0058] (1) 10 parts of washed sand, 1 part of gypsum, 10 parts of water are mixed first to form a slurry, and then mixed with 2.3 parts of ordinary Portland cement (PO.42.5), 2 parts of quicklime, 2.7 parts of fly ash, 1.5 parts of water;

[0059] (2) A certain amount of aluminum powder is dispersed in a small amount of water, wherein the mass of the aluminum powder and water is 0.08% and 0.25% of the mass of the solid powder in step (1) respectively, and after stirring uniformly, it is directly poured into the slurry prepared in step (1), first stirred rapidly in a cement paste mixer for 45s, and then stirred slowly for 30s, the slurry is quickly poured into a test mold, placed in a constant temperature and humidity standard curing box at 45°C for curing, and the gas generation is static for 4 hours; the test block after static curing is removed from the mold and sent to a steam autoclave with a saturated steam pressure of 1.5 MPa and a high temperature of 190°C for high temperature and high pressure curing, the autoclaved high-strength aerated concrete test block after autoclaving is taken out, and the compressive strength is tested, and the results are shown in Table 1. The autoclaved high-strength aerated concrete test block prepared by the aluminum powder foaming agent in this comparative example has a large number of string holes formed by uneven bubbles inside, and low compressive strength.

[0060] Comparative Example 2

[0061] The specific process steps of this comparative example are as follows:

[0062] (1) 10 parts of washed sand, 1 part of gypsum, 10 parts of water are mixed first to form a slurry, and then mixed with 2.3 parts of ordinary Portland cement (PO.42.5), 2 parts of quicklime, 2.7 parts of fly ash, 1.5 parts of water;

[0063] (2) A certain amount of aluminum powder is dispersed in a small amount of water, wherein the mass of the aluminum powder and water is 0.08% and 0.25% of the mass of the solid powder in step (1) respectively, and after stirring uniformly, it is directly poured into the slurry prepared in step (1), first stirred rapidly in a cement paste mixer for 45s, and then stirred slowly for 30s, the slurry is quickly poured into a test mold, placed in a constant temperature and humidity standard curing box at 45°C for curing, and the gas generation is static for 4 hours; the test block after static curing is removed from the mold and sent to a steam autoclave with a saturated steam pressure of 1.5 MPa and a high temperature of 190°C for high temperature and high pressure curing, the autoclaved high-strength aerated concrete test block after autoclaving is taken out, and the compressive strength is tested, and the results are shown in Table 1. The autoclaved high-strength aerated concrete test block prepared by the aluminum powder foaming agent in this comparative example has a large number of string holes formed by uneven bubbles inside, and low compressive strength.

[0064] Comparative Example 3

[0065] The specific process steps of this comparative example are as follows:

[0066] (1) 10 parts of washed sand, 1 part of gypsum, 10 parts of water were mixed to form a slurry, and then mixed with 2.3 parts of ordinary Portland cement (PO.42.5), 2 parts of quicklime, 2.7 parts of fly ash, 1.5 parts of water;

[0067] (2) A certain amount of aluminum powder and 10 g of layered double hydroxide precipitate prepared from Mg(NO3)2 and Al(NO3)3 (see Example 2 for details) were dispersed in a water solution of cocamide propyl oxide, wherein the mass of the aluminum powder and the water solution of cocamide propyl oxide was 0.08% and 0.25% of the mass of the solid powder in step (1) respectively, and the mass of cocamide propyl oxide in the water solution was 5 g. The mixture was stirred uniformly to obtain an aluminum powder liquid, which was then directly poured into the slurry prepared in step (1). The slurry was first rapidly stirred in a cement paste stirrer for 45 s and then slowly stirred for 30 s. The slurry was quickly poured into a test mold and placed in a constant temperature and humidity standard curing box at 45°C for curing. The test block was demolded after 4 hours of static curing and then placed in a steam autoclave with a saturated steam pressure of 1.5 MPa and a high temperature of 190°C for high temperature and high pressure curing. The test block cured by steam autoclaving was taken out and tested for compressive strength. The results are shown in Table 1. Compared with Comparative Example 2 and Example 2, the layered double hydroxide precipitate in this comparative example had little effect on strength. This is because the unmodified layered double hydroxide on the surface is hydrophilic, which is more easily dispersed in water during foaming rather than existing on the surface of the foam, so it cannot promote the generation of crystal products on the gas-solid surface during hydration.

[0068] Table 1

[0069]

Claims

1. A gas-liquid-solid three-phase bubble stabilizer, characterized by, The aqueous solution contains a long alkyl chain anion compound modified layered double hydroxide and a surfactant, wherein the mass ratio of the long alkyl chain anion compound to the layered double hydroxide is 1:5-1:60, calculated based on the mass of the dried layered double hydroxide; and the mass ratio of the long alkyl chain anion compound modified layered double hydroxide to the surfactant is 1:5-1:10, calculated based on the mass of the long alkyl chain anion compound modified layered double hydroxide after drying. The layered double hydroxide is prepared by a micro-channel reactor method and has an ultra-thin sheet structure with a lateral size of 20-30 nm. The long alkyl chain anionic compound is C n-1 H 2n-1 XOO - M + , n = 11-22, X represents the chemical elements C, S, P, M + represents a monovalent metal ion K + , Na + ; The general formula of the layered double hydroxide is [M 2+ 1-x M 3+ x (OH)2] x+ (A n- ) x / n ·yH2O, wherein M 2+ is any one or two of the divalent metal ions Mg 2+ , Ca 2+ , Zn 2+ ; M 3+ is Al 3+ or Fe 3+ ; A n- is any one of NO3 - , CO3 2- , or Cl - ; 0.17≤x≤0.35; 0≤y≤2; The surfactant is one or more of cocodiethanolamide, disodium lauroyl methyl bisulfate, cocamidopropyl hydroxysultaine, disodium lauryl citrate sulfosuccinate, disodium lauryl ether sulfosuccinate, sodium fatty alcohol polyethyleneglycol ether carboxylate, oleic acid diethanolamide, disodium lauryl sulfosuccinate, disodium cocamido MEA-sulfosuccinate, sodium lauroyl sarcosinate, and sodium lauroyl glutamate.

2. The gas-liquid-solid three-phase bubble stabilizer according to claim 1, characterized by, The 10-20 g layered double hydroxide precipitate is dispersed in 20 ml of a 0.005-0.1 mol / l solution of a long alkyl chain anionic compound, the ultrasonic dispersion time is 5-15 min, and the temperature is 25-35 o C.

3. The gas-liquid-solid three-phase bubble stabilizer according to claim 2, characterized in that, The mass ratio of the long alkyl chain anion compound to the layered double hydroxide is 1:10-1.5:10, calculated based on the mass of the dried layered double hydroxide.

4. An autoclaved high-strength aerated concrete panel, characterized by, The specific preparation method is as follows: (1) 10 parts of water-washed sand, 0.8-1.2 parts of gypsum, 9-11 parts of water are mixed to form a slurry, and then mixed with 2-2.6 parts of cement, 1.8-2.2 parts of quicklime, 2.5-3 parts of fly ash, and 1.2-1.8 parts of water to obtain a high-strength aerated concrete slurry; (2) a certain amount of aluminum powder for foaming is dispersed in the gas-liquid-solid three-phase foam stabilizer of claim 1, wherein the mass of the aluminum powder and the gas-liquid-solid three-phase foam stabilizer is 0.07-0.10% and 0.20-0.3% of the mass of the solid powder in step (1), respectively, and after uniform stirring, it is directly poured into the high-strength aerated concrete slurry, first stirred quickly and then stirred slowly in a cement paste mixer, the slurry is quickly poured into a test mold, and then cured in a constant temperature and humidity standard curing box for gas evolution and static setting; after the static setting and curing of the test block, the test block is demolded and cured at high temperature and high pressure.

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