CN116813371A - Aerated concrete plate maintained by using cement kiln tail flue gas and preparation method - Google Patents

Aerated concrete plate maintained by using cement kiln tail flue gas and preparation method Download PDF

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Publication number
CN116813371A
CN116813371A CN202210948489.XA CN202210948489A CN116813371A CN 116813371 A CN116813371 A CN 116813371A CN 202210948489 A CN202210948489 A CN 202210948489A CN 116813371 A CN116813371 A CN 116813371A
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aerated concrete
flue gas
kiln tail
autoclave
temperature
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夏艳晴
王宁
阳黎
种娜
钟文
刘强
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Jiahua Special Cement Co ltd
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Jiahua Special Cement Co ltd
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    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C04B28/06Aluminous cements
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B40/00Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • C04B40/02Selection of the hardening environment
    • C04B40/0272Hardening under vacuum or reduced pressure
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B40/00Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • C04B40/02Selection of the hardening environment
    • C04B40/0277Hardening promoted by using additional water, e.g. by spraying water on the green concrete element
    • C04B40/0281Hardening in an atmosphere of increased relative humidity
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/40Porous or lightweight materials
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2201/00Mortars, concrete or artificial stone characterised by specific physical values
    • C04B2201/20Mortars, concrete or artificial stone characterised by specific physical values for the density
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2201/00Mortars, concrete or artificial stone characterised by specific physical values
    • C04B2201/50Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

The invention discloses an aerated concrete slab cured by cement kiln tail flue gas and a preparation method thereof, and belongs to the technical field of concrete materials, wherein the slab is prepared by curing the cement kiln tail flue gas after desulfurization and denitration after pouring aerated concrete slurry by taking steel bars as frameworks and pouring the aerated concrete slurry, and the raw materials of the aerated concrete comprise dry materials, water and aluminum powder paste; the dry material comprises high calcium oxide-belite-calcium sulfoaluminate gelled material, fly ash and dihydrate gypsum. The invention utilizes the high calcium oxide-belite-calcium sulfoaluminate cementing material to prepare the aerated concrete plate and the steel bar preservative, which not only reduces the difference of the linear expansion coefficients of the steel bar and the aerated concrete, but also increases the additionBinding power of air concrete and steel bars. In addition, the desulfurization and denitrification cement kiln tail flue gas is utilized to maintain the aerated concrete slab, so that the heat in the flue gas is effectively utilized, and the CO of a cement plant is reduced 2 Discharge amount.

Description

Aerated concrete plate maintained by using cement kiln tail flue gas and preparation method
Technical Field
The invention belongs to the technical field of concrete materials, and particularly relates to an aerated concrete plate cured by using cement kiln tail flue gas and a preparation method thereof.
Background
Aerated concrete can be made into various types of products to meet the needs of different parts of a building. When the reinforced bars are arranged in the aerated concrete, the reinforced concrete can be manufactured into boards with different functions, and the boards mainly comprise five types of roof boards, floor boards, wall boards, decorative pattern boards and spliced wall boards.
In the production process of the aerated concrete plate, the finished plate can be cracked to a greater or lesser extent. The linear expansion coefficient of the steel bar is 12 multiplied by 10 within the range of 20 to 200 DEG C -3 mm·m -1 ·℃ -1 The linear expansion coefficient of the aerated concrete is 8 multiplied by 10 -3 mm·m -1 ·℃ -1 For example, a sheet of 3m length, which is cured by heating from 60 ℃ to 185 ℃ and in which the length of the internal steel bar is 4.5mm and the length of the aerated concrete is 3mm, has a difference in expansion of 1.5mm, is obviously one of the causes of cracking of the sheet. In order to reduce the difference of the linear expansion coefficients of the reinforced concrete and the aerated concrete, the patent publication number is CN103693928B, the patent name is autoclaved aerated concrete slab prepared by using yellow river sand and a preparation method thereof, magnesia (the main component is MgO) is doped in the aerated concrete slab, the addition of the magnesia can improve the thermal expansion coefficient of the aerated concrete, and the thermal expansion coefficient of the aerated concrete is consistent with that of the reinforced concrete as much as possible during steaming, so that the slab prepared by the patent has high compressive strength, large rigidity and small deflection value. But the calcining range of magnesiaThe magnesia calcined at the low temperature (800-900 ℃) has high digestion speed and does not have expansion effect in the steaming process, the digestion time of the magnesia calcined at the high temperature (1000-1100 ℃) is prolonged to more than 8 hours after meeting water, and the magnesia is hydrated to generate Mg (OH) in the steaming process 2 The expansion coefficient of the aerated concrete plate can be increased by volume expansion. The patent does not describe magnesia hydration time and calcination temperature.
In addition, whether or not the steel reinforcement can exert a stress in the slab depends on the binding force of the aerated concrete to the steel reinforcement, and the binding force between the steel reinforcement and the concrete is from the corrosion-resistant coating. The binding power is different due to the different compositions and properties of various preservatives. In order to strengthen the binding force of aerated concrete and steel bars, the patent publication No. CN108003708B and the patent name are an antirust agent for autoclaved sand aerated concrete plate steel bars and a preparation method thereof. However, the carboxylated styrene-butadiene latex is easy to lose efficacy, needs to be stored in a dark place, and is inconvenient to use.
In addition, the autoclaved curing process is a main means for realizing hydrothermal synthesis reaction and obtaining strength of the aerated concrete. From the current production condition of aerated concrete in China, the unit heat consumption of autoclaved aerated concrete products is 1 multiplied by 10 6 ~1.6×10 6 kJ/m 3 The heat consumption of aerated concrete curing is high, and the aerated concrete curing belongs to a high-energy-consumption product. The temperature of the cement kiln tail flue gas is higher than 300 ℃, the kiln tail flue gas after desulfurization and denitrification can be generally used for waste heat power generation and then is discharged into the air, but the discharged flue gas is rich in CO 2 Air is polluted.
Therefore, the invention provides the aerated concrete board maintained by the flue gas of the cement kiln tail and the preparation method thereof, and the aerated concrete board and the steel bar preservative are prepared by the high calcium oxide-belite-calcium sulfoaluminate cementing material, so that the difference of the linear expansion coefficients of the steel bar and the aerated concrete is reduced, and the binding force of the aerated concrete and the steel bar is increased. In addition, utilize warp releaseThe aerated concrete plate cured by the flue gas at the tail of the sulfur denitration cement kiln not only effectively utilizes the heat in the flue gas, but also reduces CO in cement factories 2 Discharge amount.
Disclosure of Invention
The invention aims to solve the technical problems that: the aerated concrete plate cured by the flue gas of the cement kiln tail and the preparation method thereof are provided to at least solve the technical problems of the part.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
an aerated concrete slab cured by using cement kiln tail flue gas is prepared by taking steel bars as a framework, pouring an aerated concrete material, and curing the cement kiln tail flue gas after desulfurization and denitrification, wherein the raw materials of the aerated concrete comprise dry materials, water and aluminum paste;
the dry material comprises 28 to 40wt.% of high calcium oxide-belite-calcium sulfoaluminate cementing material, 54 to 68wt.% of fly ash and 4 to 6wt.% of dihydrate gypsum;
the mixing amount of the aluminum powder paste is 0.8-1.2 per mill of the total dry material;
the water usage is determined by the slurry fluidity of 240 + -10 mm.
Further, the high calcium oxide-belite-calcium sulfoaluminate gelled material comprises the following components in percentage by mass:
f-CaO:24~40wt.%;
C 2 S:30~55wt.%;
1~20wt.%;
C 4 AF:0.1~10wt.%;
CaSO 4 :0.1~10wt.%。
further, the high-calcium oxide-belite-calcium sulfoaluminate cementing material is formed by high-temperature calcination of a calcareous material, a siliceous material, an aluminum material and a gypsum material, wherein the calcination temperature is 1150-1300 ℃, and the calcination time is 20-90 min.
Further, the surface of the steel bar is coated with a steel bar preservative.
Further, the reinforcing steel bar preservative is prepared from asphalt, high calcium oxide-belite-calcium sulfoaluminate cementing material, fly ash, sodium methyl siliconate and water according to the mass ratio of 3:1:1.4:0.02:3.
The preparation method of the aerated concrete plate maintained by using the flue gas of the cement kiln tail comprises the following steps:
step 1, brushing a reinforcing steel bar with a reinforcing steel bar preservative, drying and assembling into a mold, wherein the brushing thickness of the reinforcing steel bar preservative is 0.7-1 mm;
step 2, weighing the raw materials of the aerated concrete according to the proportion;
step 3, adding the weighed raw materials into a stirrer, stirring into uniform materials, pouring into a mould and vibrating;
step 4, placing the poured and vibrated slurry in a wet and hot environment for standing to obtain a gas-producing and hardening blank;
step 5, cutting and trimming the hardened blank to obtain a concrete plate;
and 6, curing the concrete plate.
Further, in the step 3, adding the weighed raw materials into a stirrer, stirring the raw materials into uniform materials with the fluidity of 220-240 mm, pouring the uniform materials into a mould, and vibrating the uniform materials for 20 seconds by using an inserted vibrator;
in the step 4, placing the poured and vibrated slurry in a damp-heat environment at 40-60 ℃ for standing for 2-3 hours to obtain a gas-producing and hardening green body.
Further, the step 6 includes:
step 61, placing the concrete plate in an autoclave, and vacuumizing;
step 62, introducing high-temperature kiln tail flue gas into a heat exchanger to prepare saturated water vapor, and slowly introducing the saturated water vapor into an autoclave to heat the autoclave;
step 63, intermittently introducing saturated water vapor into the autoclave, maintaining the temperature of the autoclave, introducing kiln tail flue gas subjected to heat exchange by a heat exchanger into the autoclave, and opening a micro-opening exhaust valve on the autoclave to enable gas in the autoclave to flow and ensure the working pressure of the autoclave;
and 64, quickly exhausting and cooling, and taking out to obtain the aerated concrete plate.
Further, in the step 62, high Wen Yaowei flue gas is introduced into a heat exchanger to prepare saturated water vapor with the temperature of more than 180 ℃;
in the step 63, saturated steam is intermittently introduced into the autoclave, the temperature of the autoclave is kept at 180-190 ℃, kiln tail smoke after heat exchange of a boiler heat exchanger is introduced into the autoclave, a micro-opening exhaust valve on the autoclave is opened, gas in the autoclave flows, the working pressure of the autoclave is ensured to be 1.5-1.7 MPa, the duration is 7-9 hours, and the temperature of the high-temperature kiln tail smoke after heat exchange of the heat exchanger is 70-120 ℃.
Further, the high-temperature kiln tail flue gas is subjected to desulfurization and denitration treatment, and CO in the kiln tail flue gas after desulfurization and denitration 2 The volume concentration is 5-20%.
The amount of reinforcing steel bars used in the invention is the prior art, and is determined according to the properties of the manufactured plate.
Compared with the prior art, the invention has the following beneficial effects:
the invention has scientific and reasonable design and convenient use, and utilizes the high calcium oxide-belite-calcium sulfoaluminate cementing material to prepare the aerated concrete plate and the steel bar preservative, thereby not only reducing the difference of the linear expansion coefficients of the steel bar and the aerated concrete, but also increasing the binding force of the aerated concrete and the steel bar. In addition, by using the aerated concrete plate after the maintenance of the flue gas at the tail of the desulfurization and denitrification cement kiln, not only the heat in the flue gas is effectively utilized, but also the CO of a cement plant is reduced 2 Discharge amount.
Drawings
FIG. 1 is an X-ray diffraction pattern of an aerated concrete panel of the invention after curing by kiln tail flue gas.
Figure 2 is a graph of lime particle morphology in the calcium oxide-belite-calcium sulfoaluminate cement of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention adopts desulfurization and denitrification kiln tail flue gas to cure the aerated concrete plate, and the mechanism is as follows: in the whole curing process, each slurry in the plate undergoes a hydration-heat seal-carbonization ternary reaction. Firstly, in the static stop stage, slurry poured into a mould undergoes the processes of gas generation, thickening, initial setting and hardening, and in the series of processes, the high calcium oxide-belite-calcium sulfoaluminate gelled material undergoes hydration reaction to generate Ca (OH) 2 Hydration products such as AFt, C-S-H gel and the like are mutually overlapped to promote hardening of the blank; secondly, in the initial stage of heat preservation and flue gas ventilation, the inner part and the outer part of the concrete are subjected to heat sealing and carbonization reaction simultaneously: outside the aerated concrete body, the hydration product Ca (OH) 2 AFt, C-S-H, and f-CaO, C in unhydrated Cement particles 2 S、C 4 AF and CO in kiln tail flue gas 2 Reacting to form CaCO 3 The crystals, the silica gel and the aluminum gel fill the microscopic pores, so that the strength of the aerated concrete is improved; and the inside of the concrete body is subjected to heat sealing reaction, ca (OH) 2 SiO in C-S-H gels and siliceous materials 2 、Al 2 O 3 Reacting to generate tobolite, aluminum-substituted tobolite and water garnet, and improving the internal strength of the blank. The high-temperature kiln tail flue gas is subjected to desulfurization and denitrification treatment SO as to prevent SO in the flue gas 2 And NO X And (5) corroding the steel bars. The invention solves the problems of recycling heat in the flue gas of the cement kiln tail and CO in the flue gas 2 The problem of gas solidification.
The invention adopts the high calcium oxide-belite-calcium sulfoaluminate cementing material as the main raw material of the aerated concrete and the steel bar preservative, does not need to additionally add magnesia, reduces the difference of thermal expansion values of the aerated concrete blank and the steel bar in the steam curing temperature rising process, and solves the problem of vertical cracks of the plate. The reason is that: high calcium oxide belite thioaluminateThe calcium cementing material is f-CaO-C 2 S-C 4 A 3 The calcining temperature of the gypsum system is 1150-1300 ℃, and a small part of f-CaO is in an overburning state (shown in figure 2), and under the conditions of high temperature and high pressure, the overburning f-CaO reacts with water to form calcium hydroxide so as to promote the expansion of the aerated concrete volume; in addition, C in the system 4 A 3 />、CaSO 4 With hydration product Ca (OH) 2 AFt is generated through dissolution and crystallization, so that the volume expansion of the blank body is promoted.
The invention adopts asphalt, high calcium oxide-belite-calcium sulfoaluminate cementing material, fly ash and sodium methyl siliconate to prepare the steel bar preservative. Under the conditions of high temperature and high pressure, products such as tobermorite, water garnet and the like are generated in the high-calcium oxide-belite-calcium sulfoaluminate cementing material in the steel bar preservative, and are consistent with the aerated concrete body products, so that the binding force between the aerated concrete and the steel bar can be increased, hydration products of the aerated concrete can be organically fused with asphalt, a framework formed by crystal bodies is formed in the asphaltene, and the strength of the outer coating of the steel bar is higher.
The reinforcement calculation of the reinforcing steel bar is performed according to the load born by the plate in the prior art, and the reinforcement structure determined after the internal force calculation is performed does not need to determine the mass ratio of materials to the reinforcing steel bar.
FIG. 1 is an X-ray diffraction diagram of an aerated concrete panel after kiln tail flue gas curing, wherein after kiln tail flue gas curing, carbonization reaction occurs outside the aerated concrete panel, and products mainly comprise aragonite, limestone, anhydrite and the like; the internal hydrothermal synthesis reaction is carried out, and the products are mainly tobermorite and water garnet. Fig. 2 is a graph showing the morphology of lime particles in the high calcium oxide-belite-calcium sulfoaluminate cement of the invention, and the crystallization phenomenon on the surfaces of free calcium particles is shown, which indicates that a small amount of overburning of calcium oxide occurs.
Example 1
An aerated concrete slab cured by using cement kiln tail flue gas is prepared by taking steel bars as a framework, pouring an aerated concrete material, and curing the cement kiln tail flue gas after desulfurization and denitrification, wherein the raw materials of the aerated concrete comprise dry materials, water and aluminum paste;
wherein the dry material comprises 40wt.% of high calcium oxide-belite-calcium sulfoaluminate cement, 54wt.% of fly ash and 6wt.% of gypsum dihydrate; the mixing amount of the aluminum powder paste is 1.2 per mill of the total amount of the dry materials; the slurry fluidity in this example was 240mm, and the water consumption was 50% of the total dry matter.
In this embodiment, the high calcium oxide-belite-calcium sulfoaluminate cement comprises the following components in percentage by mass: f-CaO:38wt.% C 2 S:50wt.%、C 4 A 3 :8wt.%、C 4 AF:2wt.%、CaSO 4 :2wt.%; the high-calcium oxide-belite-calcium sulfoaluminate cementing material is formed by high-temperature calcination of a calcareous material, a siliceous material, an aluminum material and a gypsum material, wherein the calcination temperature is 1300 ℃ and the calcination time is 30min; the surface of the steel bar is coated with a steel bar preservative; the reinforcing steel bar preservative is prepared from asphalt, high calcium oxide-belite-calcium sulfoaluminate cementing material, fly ash, sodium methyl siliconate and water according to the mass ratio of 3:1:1.4:0.02:3.
The preparation method of the aerated concrete plate comprises the following steps:
step 1, according to the requirement of a reinforcement structure, coating a reinforcement preservative with the thickness of 1mm on the surface of a reinforcement, drying, assembling into a mold, and respectively welding three transverse ribs at two ends of a tension reinforcement to serve as anchoring ribs;
step 2, weighing the raw materials of the aerated concrete according to the proportion;
step 3, adding the weighed raw materials into a stirrer, stirring the raw materials into uniform materials with the fluidity of 240mm, pouring the uniform materials into a mould, and vibrating the uniform materials for 20 seconds by using an inserted vibrator;
step 4, placing the poured and vibrated slurry in a damp-heat environment at 60 ℃ for standing for 3 hours to obtain a gas-producing and hardening blank;
step 5, cutting and trimming the hardened blank to obtain a concrete plate;
and 6, curing the concrete plate.
The step 6 comprises the following steps: step 61, placing the concrete plate in an autoclave, and vacuumizing; step 62, introducing the desulfurized and denitrified high Wen Yaowei flue gas into a heat exchanger to prepare saturated steam with the temperature of more than 180 ℃, and slowly introducing the saturated steam into an autoclave to heat the flue gas to the temperature of more than 180 ℃ within 2.5 hours; step 63, intermittently introducing saturated water vapor into the autoclave, keeping the temperature of the autoclave at 190 ℃, introducing kiln tail flue gas at 120 ℃ after heat exchange by a heat exchanger into the autoclave, and opening a micro-opening exhaust valve on the autoclave to enable the gas in the autoclave to flow while ensuring the working pressure of the autoclave to be 1.7MPa and the duration to be 9 hours; and 64, quickly exhausting and cooling, and taking out to obtain the aerated concrete plate.
The high-temperature kiln tail flue gas is subjected to desulfurization and denitration treatment, and CO in the kiln tail flue gas is subjected to desulfurization and denitration 2 The concentration was 5%.
Example 2
An aerated concrete slab cured by using cement kiln tail flue gas is prepared by taking steel bars as a framework, pouring an aerated concrete material, and curing the cement kiln tail flue gas after desulfurization and denitrification, wherein the raw materials of the aerated concrete comprise dry materials, water and aluminum paste;
wherein the dry material comprises 28wt.% of high calcium oxide-belite-calcium sulfoaluminate cement, 68wt.% of fly ash and 4wt.% of gypsum dihydrate; the mixing amount of the aluminum powder paste is 0.8 per mill of the total amount of the dry materials; the slurry in this example had a fluidity of 248mm and the water usage was 48% of the total dry matter.
In this embodiment, the high calcium oxide-belite-calcium sulfoaluminate cement comprises the following components in percentage by mass: f-CaO:34wt.%, C 2 S:43wt.%、C 4 A 3 :10wt.%、C 4 AF:7wt.%、CaSO 4 :6wt.%; the high-calcium oxide-belite-calcium sulfoaluminate cementing material is formed by high-temperature calcination of a calcareous material, a siliceous material, an aluminum material and a gypsum material, wherein the calcination temperature is 1150 ℃ and the calcination time is 90min; the surface of the steel bar is coated with a steel bar preservative; the reinforcing steel bar preservative is prepared from asphalt, high calcium oxide-belite-calcium sulfoaluminate cementing material, fly ash, sodium methyl siliconate and water according to the mass ratio of 3:1:1.4:0.02:3.
The preparation method of the aerated concrete plate comprises the following steps:
step 1, according to the requirement of a reinforcement structure, coating a reinforcement preservative with the thickness of 0.7mm on the surface of a reinforcement, drying, assembling into a mold, and respectively welding three transverse ribs at two ends of a tension reinforcement to serve as anchoring ribs;
step 2, weighing the raw materials of the aerated concrete according to the proportion;
step 3, adding the weighed raw materials into a stirrer, stirring the raw materials into uniform materials with the fluidity of 248mm, pouring the uniform materials into a mould, and vibrating the uniform materials for 20 seconds by using an inserted vibrator;
step 4, placing the poured and vibrated slurry in a wet and hot environment at 50 ℃ for standing for 3 hours to obtain a gas-producing and hardening blank;
step 5, cutting and trimming the hardened blank to obtain a concrete plate;
and 6, curing the concrete plate.
The step 6 comprises the following steps: step 61, placing the concrete plate in an autoclave, and vacuumizing; step 62, introducing the desulfurized and denitrified high Wen Yaowei flue gas into a heat exchanger to prepare saturated steam with the temperature of more than 180 ℃, and slowly introducing the saturated steam into an autoclave to heat the flue gas to the temperature of more than 180 ℃ within 2 hours; step 63, intermittently introducing saturated water vapor into the autoclave, keeping the temperature of the autoclave at 185 ℃, introducing kiln tail flue gas at 70 ℃ after heat exchange by a heat exchanger into the autoclave, and opening a micro-opening exhaust valve on the autoclave to enable the gas in the autoclave to flow while ensuring the working pressure of the autoclave to be 1.5MPa, wherein the duration time is 8 hours; and 64, quickly exhausting and cooling, and taking out to obtain the aerated concrete plate.
The high-temperature kiln tail flue gas passes throughDesulfurization and denitration treatment, and CO in kiln tail flue gas after desulfurization and denitration 2 The concentration was 20%.
Example 3
An aerated concrete slab cured by using cement kiln tail flue gas is prepared by taking steel bars as a framework, pouring an aerated concrete material, and curing the cement kiln tail flue gas after desulfurization and denitrification, wherein the raw materials of the aerated concrete comprise dry materials, water and aluminum paste;
wherein the dry material comprises 34wt.% of high calcium oxide-belite-calcium sulfoaluminate cement, 61wt.% of fly ash and 5wt.% of gypsum dihydrate; the mixing amount of the aluminum powder paste is 1 per mill of the total amount of the dry materials; the slurry fluidity in this example was 235mm, and the water consumption was 43% of the total dry matter.
In this embodiment, the high calcium oxide-belite-calcium sulfoaluminate cement comprises the following components in percentage by mass: f-CaO:34wt.%, C 2 S:46wt.%、C 4 A 3 :13wt.%、C 4 AF:5wt.%、CaSO 4 :2wt.%; the high-calcium oxide-belite-calcium sulfoaluminate cementing material is formed by high-temperature calcination of a calcareous material, a siliceous material, an aluminum material and a gypsum material, wherein the calcination temperature is 1300 ℃ and the calcination time is 20min; the surface of the steel bar is coated with a steel bar preservative; the reinforcing steel bar preservative is prepared from asphalt, high calcium oxide-belite-calcium sulfoaluminate cementing material, fly ash, sodium methyl siliconate and water according to the mass ratio of 3:1:1.4:0.02:3.
The preparation method of the aerated concrete plate comprises the following steps:
step 1, according to the requirement of a reinforcement structure, coating a reinforcement preservative with the thickness of 0.8mm on the surface of a reinforcement, drying, assembling into a mold, and respectively welding three transverse ribs at two ends of a tension reinforcement to serve as anchoring ribs;
step 2, weighing the raw materials of the aerated concrete according to the proportion;
step 3, adding the weighed raw materials into a stirrer, stirring the raw materials into uniform materials with the fluidity of 235mm, pouring the uniform materials into a mould, and vibrating the uniform materials for 20 seconds by using an inserted vibrator;
step 4, placing the poured and vibrated slurry in a damp-heat environment at 40 ℃ for standing for 3 hours to obtain a gas-producing and hardening blank;
step 5, cutting and trimming the hardened blank to obtain a concrete plate;
and 6, curing the concrete plate.
The step 6 comprises the following steps: step 61, placing the concrete plate in an autoclave, and vacuumizing; step 62, introducing the desulfurized and denitrified high Wen Yaowei flue gas into a heat exchanger to prepare saturated steam with the temperature of more than 180 ℃, and slowly introducing the saturated steam into an autoclave to heat the flue gas to the temperature of more than 180 ℃ within 2 hours; step 63, intermittently introducing saturated water vapor into the autoclave, keeping the temperature of the autoclave at 180 ℃, introducing kiln tail flue gas at 90 ℃ after heat exchange by a heat exchanger into the autoclave, and opening a micro-opening exhaust valve on the autoclave to enable the gas in the autoclave to flow while ensuring the working pressure of the autoclave to be 1.7MPa, wherein the duration time is 9 hours; and 64, quickly exhausting and cooling, and taking out to obtain the aerated concrete plate.
The high-temperature kiln tail flue gas is subjected to desulfurization and denitration treatment, and CO in the kiln tail flue gas is subjected to desulfurization and denitration 2 The concentration was 10%.
Comparative example 1
In this comparative example, a commercially available wj301 type bar rust inhibitor was used as the bar preservative, and the other conditions were the same as in example 1.
Comparative example 2
In this comparative example, the dry ingredients included 25wt.% p.o42.5r cement, 15wt.% quicklime, 54wt.% fly ash, and 6wt.% gypsum dihydrate; the mixing amount of the aluminum powder paste is 1.2 per mill of the total amount of the dry materials; in the comparative example, the fluidity of the slurry is 242mm, and the water consumption is 50% of the total dry material; the steel bar surface is coated with a steel bar rust inhibitor, the steel bar rust inhibitor is wj301 steel bar rust inhibitor, and the rest conditions are the same as those of the embodiment 1.
Comparative example 3
In this comparative example, the dry ingredients included 25wt.% p.o42.5r cement, 15wt.% quicklime, 54wt.% fly ash, and 6wt.% gypsum dihydrate; the mixing amount of the aluminum powder paste is 1.2 per mill of the total amount of the dry materials; the water consumption is 50% of the total dry material, and the fluidity of the slurry in the embodiment is 242mm; the rust inhibitor is wj301 steel bar rust inhibitor.
The preparation method was identical to example 1 except for curing in step 6. In the comparative example, the curing method adopts conventional autoclaved curing:
the curing in the step 6 comprises the following steps:
1. feeding: placing the aerated concrete blank in an autoclave, and vacuumizing;
2. heating: introducing high-temperature steam into the autoclave, and heating the autoclave to 185 ℃ for 2.5h under the pressure of 1.2MPa;
3. and (3) heat preservation: intermittently introducing saturated water vapor into the autoclave, keeping the temperature of the autoclave at 185 ℃, and keeping the temperature for 8 hours;
4. and (3) cooling: and (5) rapidly exhausting and cooling, and taking out to obtain the aerated concrete plate.
The properties of the aerated concrete prepared in examples 1 to 3 and comparative examples 1 to 3 of the present invention are shown in Table 1, and the properties of the aerated concrete panels are shown in Table 2:
table 1 physical properties of the aerated concrete panels prepared in examples 1 to 3 and comparative examples 1 to 3
Table 2 physical properties of the aerated concrete panels prepared in examples 1 to 3 and comparative examples 1 to 3
From the data in Table 1, it can be seen that hydration-heat sealing-carbon generation occurs after the aerated concrete prepared from the high calcium oxide-belite-calcium sulfoaluminate cementing material is cured by the flue gas of the desulfurization and denitrification kiln tailThe ternary reaction is performed, and the strength and the volume weight of the aerated concrete meet the requirements of GB/T15762-2020 autoclaved aerated concrete slab; comparison of comparative example 1 and example 1 shows that the rebar preservative has substantially no effect on volume weight and strength; comparing comparative example 2 with example 1, the aerated concrete prepared from conventional materials P.O42.5R and quicklime has lower strength under the condition of maintaining the flue gas at the tail of the desulfurization and denitrification kiln, and the strength does not meet the standard requirement; comparison of comparative example 3 and example 1 shows that aerated concrete prepared from conventional materials has slightly higher strength and lower volume weight after conventional curing. Example 1 has a higher volume weight than comparative example 3 because the aerated concrete absorbs CO in the flue gas due to the carbon fixation 2 Resulting in an increase in the bulk density.
As can be seen from the data in Table 2, the bonding strength of the reinforcing steel bars in the example 1 and the aerated concrete is 0.7MPa higher than that in the comparative example 1, which shows that the reinforcing steel bar preservative prepared by the invention has better bonding effect in the system. Comparative example 2 and comparative example 3 use portland cement and quicklime and use commercial rebar preservatives to improve adhesion compared to comparative example 1. In view of the above, commercial rebar preservatives are not suitable for the high calcium oxide-belite-calcium sulfoaluminate system.
In addition, it was observed that for 600×200×6000mm boards, boards made of high calcium oxide-belite-calcium sulfoaluminate cement have no cracks, whereas boards made of ordinary materials have more or less vertical cracks.
Therefore, the invention utilizes the high calcium oxide-belite-calcium sulfoaluminate cementing material to prepare the aerated concrete plate and the steel bar preservative, which not only reduces the difference of the linear expansion coefficients of the steel bar and the aerated concrete, but also increases the binding force of the aerated concrete and the steel bar. In addition, the strength and the volume weight of the aerated concrete cured by the flue gas of the desulfurization and denitrification cement kiln tail meet the standard requirements, so that the heat in the flue gas is effectively utilized, and the CO of a cement plant is reduced 2 Emission amount, energy saving and emission reduction are really realized.
Finally, it should be noted that: the above embodiments are merely preferred embodiments of the present invention for illustrating the technical solution of the present invention, but not limiting the scope of the present invention; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions; that is, even though the main design concept and spirit of the present invention is modified or finished in an insubstantial manner, the technical problem solved by the present invention is still consistent with the present invention, and all the technical problems are included in the protection scope of the present invention; in addition, the technical scheme of the invention is directly or indirectly applied to other related technical fields, and the technical scheme is included in the scope of the invention.

Claims (10)

1. The aerated concrete slab is characterized in that the slab takes steel bars as a framework, is prepared by desulfurizing and denitrating cement kiln tail flue gas after casting aerated concrete slurry, and comprises dry materials, water and aluminum powder paste as raw materials;
the dry material comprises 28 to 40wt.% of high calcium oxide-belite-calcium sulfoaluminate cementing material, 54 to 68wt.% of fly ash and 4 to 6wt.% of dihydrate gypsum;
the mixing amount of the aluminum powder paste is 0.8-1.2 per mill of the total dry material;
the amount of water is determined by the slurry fluidity of 240.+ -.10 mm.
2. The aerated concrete panel cured by using cement kiln tail fume according to claim 1, wherein the high calcium oxide-belite-calcium sulfoaluminate cementing material comprises the following components in percentage by mass:
f-CaO:24~40wt.%;
C 2 S:30~55wt.%;
C 4 AF:0.1~10wt.%;
CaSO 4 :0.1~10wt.%。
3. the aerated concrete panel cured by using the flue gas of the cement kiln tail according to claim 1, wherein the high-calcium oxide-belite-calcium sulfoaluminate cementing material is formed by high-temperature calcination of a calcareous material, a siliceous material, an aluminum material and a gypsum material, wherein the calcination temperature is 1150-1300 ℃ and the calcination time is 20-90 min.
4. An aerated concrete panel maintained by cement kiln tail fumes according to claim 1, wherein the rebar surface is coated with rebar preservative.
5. The aerated concrete panel cured by using cement kiln tail flue gas according to claim 4, wherein the steel bar preservative is prepared from asphalt, high calcium oxide-belite-calcium sulfoaluminate cementing material, fly ash, sodium methyl siliconate and water according to a mass ratio of 3:1:1.4:0.02:3.
6. A method for preparing an aerated concrete panel cured by cement kiln tail gas according to any one of claims 1 to 5, comprising the steps of:
step 1, brushing reinforcing steel bar with a reinforcing steel bar preservative, drying and assembling into a die; preferably, the coating thickness of the reinforcing steel bar preservative is 0.7-1 mm;
step 2, weighing the raw materials of the aerated concrete according to the proportion;
step 3, adding the weighed raw materials into a stirrer, stirring into uniform materials, pouring into a mould and vibrating;
step 4, placing the poured and vibrated slurry in a wet and hot environment for standing to obtain a gas-producing and hardening blank;
step 5, cutting and trimming the hardened blank to obtain a concrete plate;
and 6, curing the concrete plate.
7. The method for preparing the aerated concrete slab by using the flue gas of the cement kiln tail for curing according to claim 6, wherein in the step 3, the weighed raw materials are added into a stirrer to be stirred into uniform materials with the fluidity of 220-240 mm, and then poured into a mould, and vibrated for 20 seconds by using an inserted vibrator;
in the step 4, placing the poured and vibrated slurry in a damp-heat environment at 40-60 ℃ for standing for 2-3 hours to obtain a gas-producing and hardening green body.
8. The method for preparing an aerated concrete panel by using the flue gas from the kiln tail of cement as recited in claim 6, wherein the step 6 comprises:
step 61, placing the concrete plate in an autoclave, and vacuumizing;
step 62, introducing high-temperature kiln tail flue gas into a heat exchanger to prepare saturated water vapor, and slowly introducing the saturated water vapor into an autoclave to heat the autoclave;
step 63, intermittently introducing saturated water vapor into the autoclave, maintaining the temperature of the autoclave, introducing kiln tail flue gas subjected to heat exchange by a heat exchanger into the autoclave, and opening a micro-opening exhaust valve on the autoclave to enable gas in the autoclave to flow and ensure the working pressure of the autoclave;
and 64, quickly exhausting and cooling, and taking out to obtain the aerated concrete plate.
9. The method for preparing an aerated concrete slab by using cement kiln tail flue gas for curing according to claim 8, wherein in the step 62, high Wen Yaowei flue gas is introduced into a heat exchanger to prepare saturated water vapor with the temperature of more than 180 ℃;
in the step 63, saturated steam is intermittently introduced into the autoclave, the temperature of the autoclave is kept at 180-190 ℃, kiln tail smoke after heat exchange of a boiler heat exchanger is introduced into the autoclave, a micro-opening exhaust valve on the autoclave is opened, gas in the autoclave flows, the working pressure of the autoclave is ensured to be 1.5-1.7 MPa, the duration is 7-9 hours, and the temperature of the high-temperature kiln tail smoke after heat exchange of the heat exchanger is 70-120 ℃.
10. The preparation method according to claim 9, wherein the high-temperature kiln tail flue gas is subjected to desulfurization and denitration treatment, and CO in the kiln tail flue gas after desulfurization and denitration 2 The volume concentration is 5-20%.
CN202210948489.XA 2022-08-09 2022-08-09 Aerated concrete plate maintained by using cement kiln tail flue gas and preparation method Pending CN116813371A (en)

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CN110218040A (en) * 2019-06-27 2019-09-10 山东和悦生态新材料科技有限责任公司 Superfined flyash steam-pressing aero-concrete Self-insulation wall plate
CN112521078A (en) * 2020-12-21 2021-03-19 泰安欧士达环保材料有限公司 Production method of autoclaved aerated concrete block and autoclaved aerated concrete block
CN113956070A (en) * 2021-11-22 2022-01-21 华新水泥股份有限公司 Cement kiln tail gas carbonization autoclaved-free aerated concrete wall product and preparation method thereof

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040149170A1 (en) * 2003-02-04 2004-08-05 Osvaldo Moran Cellular concrete having normal compressive strength
CN104860556A (en) * 2014-02-24 2015-08-26 唐山北极熊建材有限公司 Fast-setting-and-hardening belite sulphate aluminum cement clinker, applications and production technology
CN104860708A (en) * 2015-05-08 2015-08-26 太原钢铁(集团)有限公司 Method for steaming and curing a fly ash aerated concrete slab
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CN113956070A (en) * 2021-11-22 2022-01-21 华新水泥股份有限公司 Cement kiln tail gas carbonization autoclaved-free aerated concrete wall product and preparation method thereof

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