CN117534379A - Low-carbon concrete for curing tail smoke of cement kiln and preparation method thereof - Google Patents

Low-carbon concrete for curing tail smoke of cement kiln and preparation method thereof Download PDF

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CN117534379A
CN117534379A CN202311519614.6A CN202311519614A CN117534379A CN 117534379 A CN117534379 A CN 117534379A CN 202311519614 A CN202311519614 A CN 202311519614A CN 117534379 A CN117534379 A CN 117534379A
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concrete
low
carbon
calcium
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李叶青
张恒
陈超
余松柏
任政
魏洋
秦节发
金胜
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Huaxin Cement Co Ltd
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Huaxin Cement Co Ltd
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    • C04B12/00—Cements not provided for in groups C04B7/00 - C04B11/00
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    • C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
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    • C04B7/00—Hydraulic cements
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    • C04B7/00—Hydraulic cements
    • C04B7/24—Cements from oil shales, residues or waste other than slag
    • C04B7/243—Mixtures thereof with activators or composition-correcting additives, e.g. mixtures of fly ash and alkali activators
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    • C04B7/00—Hydraulic cements
    • C04B7/24—Cements from oil shales, residues or waste other than slag
    • C04B7/26—Cements from oil shales, residues or waste other than slag from raw materials containing flue dust, i.e. fly ash
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    • C04B7/00—Hydraulic cements
    • C04B7/24—Cements from oil shales, residues or waste other than slag
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Abstract

The invention discloses low-carbon concrete for curing cement kiln tail flue gas, which comprises the following components in parts by weight: 10-50 parts of low-carbon cement, 5-25 parts of calcium-rich cementing material, 1-3 parts of auxiliary material, 85-110 parts of coarse aggregate, 60-100 parts of fine aggregate, 0.5-1 part of additive and 12-20 parts of water; the auxiliary material comprises Na 2 CO 3 And Na (Na) 2 SiO 3 The method comprises the steps of carrying out a first treatment on the surface of the Wherein, the whole water is firstly mixed with partial calcium-rich cementing material and introduced with CO 2 Pre-carbonizing to obtain pre-carbonated solution, and mixing with other materials. The invention uniformly introduces in-situ generated nano calcium carbonate into the concrete by a precarbonation technology, and then uses cement kiln tail flue gas to carry out stepwise carbonization maintenance on the blank body to prepare a low-carbon concrete finished product; the composite material has good mechanical property, durability and the like, has obvious economic and environmental benefits, and is suitable for large-scale popularization and application.

Description

Low-carbon concrete for curing tail smoke of cement kiln and preparation method thereof
Technical Field
The invention belongs to the technical field of building materials, and particularly relates to low-carbon concrete for curing cement kiln tail flue gas and a preparation method thereof.
Background
Carbon dioxide utilization and sequestration technologies are considered as important technological pathways for achieving emission abatement and as important means for coping with climate change. In the field of building materials, it depends on the low-calcium silicate mineral CS, gamma-C 2 S、C 3 S 2 And the like have the advantages of strong carbon fixing capability and low carbon emission, and low-calcium carbonized products formed by carbonization maintenance are gradually becoming research hot spots.
The scholars at home and abroad develop a series of novel carbon-fixing building material products based on the carbonization performance of the low-calcium silicate minerals. Patent CN109796169B discloses a preparation method of composite reinforced carbonized preform, which takes calcium silicate mineral with low calcium-silicon ratio as main raw material, and adds active magnesium oxide and alkali metal nitrate solution as composite reinforced phase, and obtains high grade by accelerating carbonizationComposite reinforced carbonized preform. Patent CN114873979B discloses a low-carbon cement concrete and a preparation method thereof, wherein low-calcium cement is taken as a main carbonization component, hydration active cementing materials are introduced to provide early form removal strength, the residual components are mixed and then are rapidly poured and formed, and the low-carbon cement concrete is obtained by placing the low-calcium cement into a carbonization reaction kettle for accelerated carbonization after form removal. However, to improve the mechanical properties and carbon fixation properties of low-calcium carbonized products, most accelerated carbonization is performed with higher carbon dioxide concentration or even pure CO 2 The method is carried out under the atmosphere condition, which undoubtedly increases the energy consumption and the cost of carbon capture and enrichment, and also puts higher requirements on corresponding production equipment, which is contrary to the original purpose of energy conservation and emission reduction.
The tail gas of cement kiln is waste exhaust gas in cement production process, and its main component is CO 2 、NO x The concentration of carbon dioxide is generally 10-30%, and researchers use industrial flue gas to maintain low-calcium cement, so as to develop a series of low-strength building products. However, when the cement kiln tail flue gas is used for curing high-strength building material products such as low-calcium cement concrete products, the carbon dioxide pressure and concentration of the cement kiln tail flue gas are low, and the temperature and humidity are high, so that the carbon dioxide is unfavorable for fully reacting with active components in the building products, the carbonization reaction degree and carbonization depth are limited, and the strength of the products is low. Therefore, the existing cement kiln tail flue gas is mostly used for curing products such as aerated blocks, solid bricks, plates and the like with low requirements on strength or size. Further explores the application of the cement kiln tail flue gas in high-strength building material products, and has important research and application significance.
Disclosure of Invention
Aiming at the defects in the prior art, the main purpose of the invention is to provide low-carbon concrete for curing the flue gas of the cement kiln tail, wherein nano calcium carbonate generated in situ is uniformly introduced into the concrete through a precarbonation technology, a large number of nucleation sites are provided for products in early hydration and later carbonization processes, and then the flue gas of the cement kiln tail is utilized to carry out stepwise carbonization curing on blanks, so that a low-carbon concrete finished product is prepared; CO can be absorbed in a large amount in the concrete preparation process 2 The carbon emission of cement enterprises is obviously reduced,meanwhile, the preparation process is simple, the production period is short, the production cost is low, and the prepared low-carbon concrete product can be suitable for large-scale popularization and application, and has good mechanical properties, durability and the like.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the low-carbon concrete for curing the cement kiln tail flue gas comprises the following components in parts by weight: 10-50 parts of low-carbon cement, 5-25 parts of calcium-rich cementing material, 1-3 parts of auxiliary material, 85-110 parts of coarse aggregate, 60-100 parts of fine aggregate, 0.5-1 part of additive and 12-20 parts of water; the auxiliary material comprises Na 2 CO 3 And Na (Na) 2 SiO 3 The method comprises the steps of carrying out a first treatment on the surface of the Wherein, the whole water is firstly mixed with partial calcium-rich cementing material and introduced with CO 2 Pre-carbonizing to obtain pre-carbonated solution, and mixing with other materials.
In the scheme, the mass ratio of the calcium-rich cementing material to water (water for all low-carbon concrete) adopted in the pre-carbonated solution is 0.01-0.09:1; preferably 0.02 to 0.06:1.
Further, the preparation method of the pre-carbonated solution specifically comprises the following steps: uniformly mixing part of the calcium-rich cementing material with water, and continuously introducing CO 2 Stirring to obtain a precarbonated solution.
In the above scheme, the CO 2 The introducing speed is 1-10L/min; CO is introduced into 2 Until the pH value of the obtained pre-carbonated solution is 6.0-9.0.
In the above scheme, the stirring speed is 1000-2000 rpm.
In the scheme, the ratio of the pre-carbonated solution to the total mass of the low-carbon cement and the residual calcium-rich cementing material is 0.1-0.8:1.
Further, the ratio of the pre-carbonated solution to the total mass of the low-carbon cement and the residual calcium-rich cementing material is 0.2-0.4:1.
In the scheme, ca/Si of the low-carbon cement is 1.0-1.5, and the specific surface area is 300-750 m 2 /kg。
Further, each chemical component in the low-carbon cement and the mass of each chemical componentThe percentages are as follows: CS 60-80%, C 3 S 2 10～30％，β-C 2 S 0～10％，f-CaO 0～5％。
In the scheme, the calcium-rich cementing material can be selected from more than one of slag, high-calcium fly ash, steel slag, electroplated stone slag, kiln dust and the like; the content of CaO in the alkaline oxide in the chemical composition is more than 35 weight percent, and the specific surface area is more than 800m 2 /kg。
Preferably, the calcium-rich cementing material is one or two of high-calcium fly ash and slag.
In the scheme, na in the auxiliary material 2 CO 3 With Na and Na 2 SiO 3 The mass ratio of (2) is 10:1-5.
In the scheme, the additive is a polycarboxylic acid water reducer, and the water reducing rate is 30-50%.
In the scheme, the coarse aggregate is continuously mixed crushed stone with the particle size of 5-25 mm; the grain diameter of the fine aggregate is 0-5 mm, and the fineness modulus is 2.1-3.5.
The preparation method of the low-carbon concrete for curing the cement kiln tail flue gas comprises the following preparation steps:
1) Mixing part of the calcium-rich cementing material with all water, and introducing CO into the obtained mixed solution 2 Stirring to react until the pH value is 6.0-9.0, thus obtaining a pre-carbonated solution;
2) Uniformly mixing the weighed low-carbon cement, the rest calcium-rich cementing material, the pre-carbonation solution, the auxiliary agent material, the coarse aggregate and the fine aggregate, adding an additive, and stirring to obtain a concrete mixture; pouring and vibration molding; removing the mould after natural curing to obtain a concrete product;
3) Transferring the obtained concrete product into a reaction container with an air inlet valve and an air outlet valve for vacuumizing treatment; then continuously introducing kiln tail flue gas until the pressure in the reaction container reaches normal pressure; opening an exhaust valve, continuously introducing kiln tail smoke, forming circulating kiln tail smoke in the reaction container, and performing normal-pressure maintenance; and closing the exhaust valve, continuously introducing kiln tail flue gas until the pressure in the carbonization kettle is 0.3-0.6 MPa, and then performing pressurized curing in a closed (stopping introducing kiln tail flue gas) reaction environment to obtain the low-carbon concrete finished product.
In the scheme, the CO of the kiln tail gas 2 The concentration is 10-30 vol%, the temperature is 70-100 ℃, the humidity is 40-80%, the inlet flow rate and the exhaust flow rate are the same, and the air flow rate per minute is 1/20-1/5 of the volume of the reaction container.
In the scheme, the natural curing time in the step 2) is 12-24 hours.
In the scheme, the normal pressure maintenance time in the step 3) is 2-12 hours; the pressure curing time is 12-30 h.
Compared with the prior art, the invention has the beneficial effects that:
1) The auxiliary agent material adopted by the invention mainly comprises Na 2 CO 3 And Na (Na) 2 SiO 3 The composition can provide an overbased environment, so that the low-carbon cement and the calcium-rich cementing material are subjected to mineral bonding reaction, si, al and Ca ions on the surface of minerals are dissolved out, and the N-C-S- (A) -H gel and the micro calcite crystal are formed through polymerization, dehydration and hardening, so that a certain early strength is provided for the obtained test piece, the die stripping period of the test piece is shortened, and the production efficiency of the product is greatly improved.
2) The invention adopts the pre-carbonation technology, firstly, carbon dioxide and Ca in slurry are introduced into a low-concentration mixed solution formed by partial calcium-rich cementing material and all water 2+ Forming proper amount of nano calcium carbonate micro-crystal (pH value of pre-carbonated solution is 6.0-9.0), uniformly distributing the nano calcium carbonate micro-crystal in the mixed solution under high-speed stirring, and doping the obtained pre-carbonated slurry into concrete, so that heterogeneous nucleation sites can be provided for early hydration of the concrete, and early strength of a test piece is improved; meanwhile, part of nano calcium carbonate microcrystals can provide growth nucleation points for concrete carbonized products, can accelerate the subsequent carbonization reaction process and greatly improve the carbonization degree of the blank.
3) The invention adopts a stepwise carbonization technology, firstly, the circulated flue gas is introduced into a vacuum reaction vessel for carbonization, the carbon dioxide with normal pressure and low concentration continuously permeates into the center of a concrete blank body and reacts with calcium ions and water to generate carbonized products, and meanwhile, the circulated flue gas flow of kiln tail canThe humidity inside the concrete is regulated, a good humidity environment is provided for carbonization reaction, and carbon dioxide diffusion inside the green body is facilitated; in the second step, under the condition of pressurization, the high-pressure flue gas rapidly permeates and diffuses into the internal pores of the concrete and rapidly reacts with the carbonized component to generate CaCO 3 And silica gel with high polymerization degree greatly improves the mechanical property of concrete, and simultaneously, a large amount of flue gas at the kiln tail is solidified and absorbed, so that the carbon emission is reduced.
4) According to the low-carbon concrete, the industrial flue gas is directly used for carbonization maintenance, CO2 purification, enrichment and other treatments are not needed for the industrial flue gas, the industrial flue gas is turned into wealth, the cost and energy consumption for capturing and enriching carbon can be effectively reduced, meanwhile, the temperature and humidity characteristics of the industrial flue gas are fully utilized to accelerate blank carbonization maintenance, the production energy consumption is greatly reduced, and the equipment requirements and the production cost can be effectively reduced.
5) The low-carbon concrete prepared by the method has low carbon footprint, and the related preparation process is simple, the production period is short and the production cost is low; the prepared low-carbon concrete product has excellent comprehensive performance, can meet various actual engineering requirements, and is suitable for large-scale popularization and application.
Detailed Description
The invention is not limited to the embodiments described above, but a number of modifications and adaptations can be made by a person skilled in the art without departing from the principle of the invention, which modifications and adaptations are also considered to be within the scope of the invention. What is not described in detail in this specification is prior art known to those skilled in the art.
In the following examples, the low-carbon cement had Ca/Si of 1.15 and a specific surface area of 550m 2 /kg; the calcium-rich cementing material is high-calcium fly ash, wherein the CaO content is 35.6%, and the SiO is formed by 2 Content 38.2%, al 2 O 3 Content 18.2%, specific surface area 900m 2 /kg; the auxiliary agent material consists of 5 parts of industrial pure sodium carbonate and 1 part of sodium silicate; the coarse aggregate is continuously mixed dolomite gravels with the particle size of 5-25 mm; the fine aggregate grain size is 0-5 mm of machine-made sand, and the fineness modulus is 3.1; the water reducer is a polycarboxylic acid water reducer provided by Su Bote, and the water reducing rate is 45%.
In the following examples, the concrete strength test pieces were 150X 150mm in size, strength testing is carried out by referring to the test method of physical and mechanical properties of concrete (GBT 50081-2019); concrete durability is carried out by referring to relevant regulations of the method Standard for testing the long-term performance and durability of common concrete (GBT 50082-2009); the carbon emission estimation is referred to the building carbon emission calculation Standard (GB/T51366-2019) and the cement and concrete green Low carbon manufacturing technology.
Example 1
The low-carbon concrete for curing the cement kiln tail flue gas comprises the following raw materials in parts by mass: 12 parts of low-carbon cement, 12.32 parts of calcium-rich cementing material, 1.5 parts of auxiliary material, 90 parts of coarse aggregate, 70 parts of fine aggregate, 0.6 part of water reducer and 15.68 parts of water; the preparation method comprises the following steps:
1) Preparation of a Pre-carbonated solution
a. Uniformly mixing 15.68 parts of water with 0.32 part of calcium-rich cementing material to obtain a mixed solution;
b. CO was stirred at 1500rpm 2 Continuously introducing the mixture into the obtained mixed solution at a flow rate of 3L/min to perform full reaction until the pH value of the slurry is 8, so as to obtain a pre-carbonated solution (16 parts);
2) Preparation of concrete
a. Uniformly mixing 12 parts of low-carbon cement, 12 parts of calcium-rich cementing material, 16 parts of precarbonated solution, 1.5 parts of auxiliary agent material, 90 parts of coarse aggregate and 70 parts of fine aggregate, and adding 0.6 part of water reducer to stir to obtain a concrete mixture;
b. pouring the concrete mixture into a mould, and performing vibration molding;
c. naturally curing for 15 hours, and removing the mould to obtain a concrete product;
3) Concrete carbonization maintenance
a. The product is moved into a carbonization kettle with an air inlet valve and an air outlet valve for vacuumizing treatment;
b. continuously introducing kiln tail smoke into a closed carbonization kettle until the pressure in the kettle reaches normal pressure;
c. opening an exhaust valve to enable kiln tail smoke to be discharged into a circulating air storage tank to form circulating kiln tail smoke, and curing for 6 hours under normal pressure under the condition of circulating kiln tail smoke;
d. immediately closing the exhaust valve, introducing kiln tail flue gas until the pressure in the carbonization kettle is 0.4MPa, and curing for 20 hours to obtain a low-carbon concrete finished product.
In this example, CO of industrial flue gas is used 2 The concentration is 15vol%, the temperature is 80 ℃, the humidity is 70%, and the air flow per minute is 1/15 of the volume of the carbonization kettle.
Example 2
The low-carbon concrete for curing the cement kiln tail flue gas comprises the following raw materials in parts by mass: 25 parts of low-carbon cement, 18.48 parts of calcium-rich cementing material, 2 parts of auxiliary materials, 100 parts of coarse aggregate, 75 parts of fine aggregate, 0.9 part of water reducer and 15.52 parts of water; the preparation method comprises the following steps:
1) Preparation of the pre-carbonated solution:
a. uniformly mixing 15.52 parts of water with 0.48 part of calcium-rich cementing material to obtain a mixed solution;
b. CO was stirred at 1500rpm 2 Continuously introducing the mixture into the obtained mixed solution at a flow rate of 3L/min to perform full reaction until the pH value of the slurry is 7.5, so as to obtain a pre-carbonated solution (16 parts);
2) Preparation of concrete
a. Uniformly mixing 25 parts of low-carbon cement, 18 parts of calcium-rich cementing material, 16 parts of pre-carbonation solution, 2 parts of auxiliary agent material, 100 parts of coarse aggregate and 75 parts of fine aggregate, and adding 0.9 part of water reducer to stir to obtain a concrete mixture;
b. pouring the concrete mixture into a mould, and performing vibration molding;
c. naturally curing for 15 hours, and removing the mould to obtain a concrete product;
3) Concrete carbonization maintenance
a. The product is moved into a carbonization kettle with an air inlet valve and an air outlet valve for vacuumizing treatment;
b. continuously introducing kiln tail smoke into a closed carbonization kettle until the pressure in the kettle reaches normal pressure;
c. opening an exhaust valve to enable kiln tail smoke to be discharged into a circulating air storage tank to form circulating kiln tail smoke, and enabling the kiln tail smoke to be at normal pressure for 8 hours under the condition of circulating kiln tail smoke;
d. immediately closing the exhaust valve, introducing kiln tail flue gas until the pressure in the carbonization kettle is 0.4MPa, and curing for 24 hours to obtain a low-carbon concrete finished product.
In the above scheme, the CO of the industrial flue gas 2 The concentration is 20vol%, the temperature is 80 ℃, the humidity is 60%, and the air flow per minute is 1/15 of the volume of the carbonization kettle.
Example 3
The low-carbon concrete for curing the cement kiln tail flue gas comprises the following raw materials in parts by mass: 40 parts of low-carbon cement, 22.8 parts of calcium-rich cementing material, 3 parts of auxiliary materials, 95 parts of coarse aggregate, 90 parts of fine aggregate, 1 part of water reducer and 15.2 parts of water; the preparation method comprises the following steps:
1) Preparation of the pre-carbonated solution:
a. uniformly mixing 15.2 parts of water with 0.8 part of calcium-rich cementing material to obtain a mixed solution;
b. CO was stirred at 1500rpm 2 Continuously introducing the mixture into the obtained mixed solution at a flow rate of 3L/min to perform full reaction until the pH value of the slurry is 7.5, so as to obtain a pre-carbonated solution (16 parts);
2) Preparation of concrete
a. Uniformly mixing 40 parts of low-carbon cement, 22 parts of calcium-rich cementing material, 16 parts of pre-carbonation solution, 3 parts of auxiliary agent material, 95 parts of coarse aggregate, 90 parts of fine aggregate, and adding 1 part of water reducer to stir to obtain a concrete mixture;
b. pouring the concrete mixture into a mould, and performing vibration molding;
c. naturally curing for 15 hours, and removing the mould to obtain a concrete product;
3) Concrete carbonization maintenance
a. The product is moved into a carbonization kettle with an air inlet valve and an air outlet valve for vacuumizing treatment;
b. continuously introducing kiln tail smoke into a closed carbonization kettle until the pressure in the kettle reaches normal pressure;
c. opening an exhaust valve to enable kiln tail smoke to be discharged into a circulating air storage tank to form circulating kiln tail smoke, and curing for 10 hours under normal pressure under the condition of circulating kiln tail smoke;
d. immediately closing the exhaust valve, introducing kiln tail flue gas until the pressure in the carbonization kettle is 0.5MPa, and curing for 24 hours to obtain a low-carbon concrete finished product.
In the above scheme, the CO of the industrial flue gas 2 The concentration is 20vol%, the temperature is 90 ℃, the humidity is 60%, and the air flow per minute is 1/10 of the volume of the carbonization kettle.
Comparative example 1
The low-carbon concrete for curing the cement kiln tail flue gas comprises the following raw materials in parts by mass: 25 parts of low-carbon cement, 18.48 parts of calcium-rich cementing material, 100 parts of coarse aggregate, 75 parts of fine aggregate, 0.9 part of water reducer and 15.52 parts of water.
The preparation is the same as in example 2 and will not be described here:
comparative example 2
The low-carbon concrete for curing the cement kiln tail flue gas comprises the following components in parts by mass: 25 parts of low-carbon cement, 18.48 parts of calcium-rich cementing material, 15.52 parts of water, 2 parts of auxiliary materials, 100 parts of coarse aggregate, 75 parts of fine aggregate and 0.9 part of water reducer; the preparation process was substantially the same as in example 2, except that the preparation of the pre-carbonated solution of step 1) was not performed in advance.
Comparative example 3
The low-carbon concrete for curing the cement kiln tail flue gas comprises the following components in parts by mass: 25 parts of low-carbon cement, 19.6 parts of calcium-rich cementing material, 2 parts of auxiliary materials, 100 parts of coarse aggregate, 75 parts of fine aggregate, 0.9 part of water reducer and 4.4 parts of water; the preparation method is substantially the same as in example 1, except that the preparation steps of the pre-carbonated solution are as follows: a. mixing 14.4 parts of water with 1.6 parts of calcium-rich cementing material to obtain slurry; b. CO is processed by 2 Continuously introducing the mixture into the slurry stirred at 1500r/s for full reaction until the pH value of the slurry is 7.5, and obtaining the pre-carbonated solution.
Comparative example 4
The low-carbon concrete for curing the cement kiln tail flue gas comprises the following raw materials in parts by mass: 25 parts of low-carbon cement, 18.48 parts of calcium-rich cementing material, 2 parts of auxiliary materials, 100 parts of coarse aggregate, 75 parts of fine aggregate, 0.9 part of water reducer and 15.52 parts of water; the preparation method is approximately the same as the embodiment, and is different in that after curing to obtain the concrete product, the circulating kiln tail flue gas is directly introduced for carbonization curing for 32 hours to obtain the concrete product.
Comparative example 5
25 parts of low-carbon concrete low-carbon cement for curing cement kiln tail flue gas, which comprises the following raw materials in parts by weight: 18.48 parts of calcium-rich cementing material, 2 parts of auxiliary material, 100 parts of coarse aggregate, 75 parts of fine aggregate, 0.9 part of water reducer and 15.52 parts of water; the preparation method is approximately the same as the embodiment, and is different in that after curing to obtain a concrete product, 0.4MPa kiln tail flue gas is directly introduced for carbonization curing for 32 hours to obtain a concrete product.
Comparative example 6
The low-carbon concrete for curing the cement kiln tail flue gas comprises the following components in parts by mass: 25 parts of low-carbon cement, 18.48 parts of calcium-rich cementing material, 2 parts of auxiliary materials, 100 parts of coarse aggregate, 75 parts of fine aggregate, 0.9 part of water reducer and 15.52 parts of water; the preparation method is almost the same as the embodiment, except that after curing to obtain the concrete product, pure CO is directly introduced 2 And (3) carbonizing and curing under the atmosphere, wherein the carbonization system is as follows: the pressure is 0.4MPa, the temperature is 80 ℃, and the carbonization and maintenance are carried out for 32 hours; and obtaining a concrete finished product.
Comparative example 7
A common concrete comprises the following components in percentage by mass: 28 parts of PO42.5 cement, 5 parts of fly ash, 6 parts of mineral powder, 100 parts of coarse aggregate, 90 parts of fine aggregate, 16.5 parts of water and 0.6 part of water reducer, uniformly mixing the materials, forming, naturally curing for 24 hours, removing a die, and transferring into a curing room for standard curing for 28 days.
The concretes obtained in examples 1 to 3 and comparative examples 1 to 7 were subjected to mechanical properties, durability tests and carbon emission estimation, respectively, and the results are shown in Table 1, and the carbon emission of the different materials in the concretes are shown in Table 2.
TABLE 1 Performance test of the concretes obtained in examples 1 to 3 and comparative examples 1 to 7 and carbon emission amount
TABLE 2 carbon emissions of different materials in concrete
The invention is not limited to the embodiments described above, but a number of modifications and adaptations can be made by a person skilled in the art without departing from the principle of the invention, which modifications and adaptations are also considered to be within the scope of the invention. What is not described in detail in this specification is prior art known to those skilled in the art.

Claims (10)

1. The low-carbon concrete for curing the cement kiln tail flue gas is characterized by comprising the following components in parts by weight: 10-50 parts of low-carbon cement, 5-25 parts of calcium-rich cementing material, 1-3 parts of auxiliary material, 85-110 parts of coarse aggregate, 60-100 parts of fine aggregate, 0.5-1 part of additive and 12-20 parts of water; the auxiliary material comprises Na 2 CO 3 And Na (Na) 2 SiO 3 The method comprises the steps of carrying out a first treatment on the surface of the Wherein, the whole water is firstly mixed with partial calcium-rich cementing material and introduced with CO 2 Pre-carbonizing to obtain pre-carbonated solution, and mixing with other materials.
2. The low carbon concrete of claim 1, wherein the mass ratio of calcium-rich cementitious material to water employed in the pre-carbonation solution is 0.01 to 0.09:1.
3. The low carbon concrete of claim 1, wherein the CO 2 The introducing speed is 1-10L/min; CO is introduced into 2 The pH value of the obtained precarbonated solution is 6.0-9.0.
4. The low carbon concrete of claim 1, wherein the ratio of the pre-carbonated solution to the total mass of low carbon cement and remaining calcium-rich cementitious material is 0.1-0.8:1.
5. The low carbon concrete according to claim 1, wherein the Ca/Si of the low carbon cement is 1.0-1.5 and the specific surface area is 300-750 m 2 /kg。
6. The low carbon concrete of claim 1, wherein the calcium-rich cementitious material is one or more of slag, high calcium fly ash, steel slag, electroplated stone slag, kiln dust; the content of CaO in the alkaline oxide in the chemical composition is more than 35 percent, and the specific surface area is more than 800m 2 /kg。
7. The low carbon concrete of claim 1, wherein Na in the adjuvant material 2 CO 3 With Na and Na 2 SiO 3 The mass ratio of (2) is 10:1-5.
8. The low carbon concrete of claim 1, wherein the admixture is a polycarboxylate water reducer having a water reduction rate of 30-50%.
9. The method for preparing the low-carbon concrete by curing the flue gas of the cement kiln tail according to any one of claims 1 to 8, which is characterized by comprising the following preparation steps:
1) Mixing part of the calcium-rich cementing material with all water, and introducing CO into the obtained mixed solution 2 Stirring to react until the pH value is 6.0-9.0, thus obtaining a pre-carbonated solution;
2) Uniformly mixing the weighed low-carbon cement, the rest calcium-rich cementing material, the pre-carbonation solution, the auxiliary agent material, the coarse aggregate and the fine aggregate, and adding an additive to stir to obtain a concrete mixture; pouring and vibration molding; removing the mould after natural curing to obtain a concrete product;
3) Transferring the obtained concrete product into a reaction container with an air inlet valve and an air outlet valve for vacuumizing treatment; then continuously introducing kiln tail flue gas until the pressure in the reaction container reaches normal pressure; opening an exhaust valve, continuously introducing kiln tail smoke, forming circulating kiln tail smoke in the reaction container, and performing normal-pressure maintenance; and closing the exhaust valve, continuously introducing kiln tail flue gas until the pressure in the carbonization kettle is 0.3-0.6 MPa, and then performing pressurized curing in a closed reaction environment to obtain the low-carbon concrete finished product.
10. The method according to claim 9, wherein the CO of the kiln tail gas 2 The concentration is 10-30 vol%, the temperature is 70-100 ℃ and the humidity is 40-80%; the gas flow rate per minute is 1/20 to 1/5 of the volume of the reaction vessel.
CN202311519614.6A 2023-11-15 2023-11-15 Low-carbon concrete for curing tail smoke of cement kiln and preparation method thereof Pending CN117534379A (en)

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