Negative carbon type composite material and preparation method thereof

Abstract

The invention discloses a negative carbon type composite material, which is prepared from the following ingredients in parts by weight: 50 to 130 parts of vaterite type calcium carbonate, 0.2 to 2.5 parts of magnesium salt, 1.0 to 4.5 parts of strontium salt, 10 to 70 parts of water and 0.03 to 4 parts of organic filling materials. The organic filling material is triethanolamine; magnesium salt and strontium salt are dissolved in water, the organic filling material is added and stirred and dispersed, and a homogeneous mixed solution is obtained; stirring and mixing vaterite type calcium carbonate and the homogeneous mixed solution until a slurry state appears; pouring the slurry into a mold for curing and forming; the organic filling material adopted by the invention not only can be compatible with other components in the cementing material, but also can form a stable network structure in the drying process, so that pores are effectively reduced, the overall compactness and mechanical strength of the material are improved, and due to the improvement, the material has excellent performance in engineering application for bearing heavy load or requiring high durability.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and specifically relates to a negative carbon composite material and a preparation method thereof. Background Art

[0002] The carbon footprint of traditional materials such as cement and steel, as well as modern materials such as organic and composite materials, during their production and use, poses a major challenge to environmental sustainability. To meet this challenge, the industry is exploring low-carbon solutions, including the use of renewable energy, optimization of production processes, and the use of new catalysts and additives to reduce the carbon footprint of the production process. Despite the challenges of cost, performance and large-scale production, the development of environmentally friendly new materials is the key to the low-carbon transformation of the materials industry. This is not only responsible for the environment, but also the only way to drive the industry towards a more sustainable future. With the global pursuit of a low-carbon economy, this transformation of the materials industry has become an irreversible trend, providing broad development space for the development of future environmentally friendly new materials.

[0003] Recently, a new type of negative carbon cementitious material has emerged. This material uses soluble calcium resources in industrial byproducts to chemically fix CO2, achieving negative carbon emissions and combating global climate change. This material not only reduces dependence on natural resources, but also has the potential for application in many fields due to its environmental friendliness and cost-effectiveness. However, although this new type of cementitious material has significant advantages in environmental protection, it has certain limitations in mechanical properties.

[0004] Specifically, during the transformation of vaterite to aragonite, the needle-shaped aragonite crystals overlap each other. Although this can give the system a certain strength, the overlap between the crystals is not perfect, resulting in a large number of pores between the crystals. The presence of these pores significantly reduces the density of the material, thereby affecting the mechanical properties of the material. The lack of mechanical properties limits the application of this new type of cementitious material in a wider range of fields, especially in projects that bear large loads or require high durability.

[0005] In order to solve this problem, the inventors have tried a variety of methods, including optimizing the growth conditions of aragonite crystals and adding different types of admixtures, but these methods often only bring limited improvements and may increase production costs or introduce new environmental problems. Therefore, how to effectively improve the mechanical properties of new cementitious materials while maintaining their environmental characteristics has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] The purpose of the present invention is to provide a negative carbon type composite material and a preparation method thereof, by adding a specific organic filling material to fill the internal pores during the molding and stirring process, thereby significantly improving the mechanical properties of the negative carbon type cementitious material.

[0007] A negative carbon composite material, the composition of which is as follows by weight:

[0008] 50-130 parts of vaterite calcium carbonate, 0.2-2.5 parts of magnesium salt, 1.0-4.5 parts of strontium salt, 10-70 parts of water, and 0.03-4 parts of organic filler; the organic filler is triethanolamine.

[0009] According to the above scheme, the magnesium salt is one or a mixture of MgCl2 and Mg(NO3)2.

[0010] According to the above scheme, the strontium salt is one or a mixture of SrCl2 and Sr(NO3)2.

[0011] According to the above scheme, the vaterite type calcium carbonate is prepared in the following manner:

[0012] The CO2-containing tail gas is passed into the calcium-rich solution after the salt is extracted with water by bubbling method to obtain a suspension containing calcium carbonate precipitate;

[0013] The suspension is filtered and dried to obtain vaterite-type calcium carbonate.

[0014] According to the above scheme, the calcium-rich solution is the filtrate obtained by washing and salt extraction of the bypass ash from the cooperative kiln, wherein Ca 2+ Concentration ≥0.05mol / L.

[0015] According to the above scheme, the CO2-containing tail gas is industrial flue gas, in which the CO2 concentration is 10vt% to 37vt%.

[0016] The method for preparing the above-mentioned negative carbon composite material comprises the following steps:

[0017] (1) dissolving magnesium salt and strontium salt in water, adding organic filler material, stirring and dispersing, and obtaining a homogeneous mixed solution;

[0018] (2) stirring and mixing the vaterite calcium carbonate and the above homogeneous mixed solution until a slurry state is formed;

[0019] (3) pouring the slurry into a mold and curing it.

[0020] According to the above scheme, the curing conditions include: steam curing at 50-90°C for 1-8 hours and then demolding; and drying at 90-130°C for 8-20 hours to obtain a negative carbon composite material.

[0021] The present invention directionally regulates the transformation of vaterite to aragonite by adding magnesium salt in the system, and the needle-shaped aragonite crystals formed overlap each other so that the system obtains strength. In addition, since strontium carbonate and aragonite calcium carbonate have highly consistent crystal structures, strontium atoms can occupy some calcium atom sites in aragonite to form solid solution during the crystal transformation process, so that the system obtains higher strength. Since the nitrogen atom in the triethanolamine group has a lone pair of electrons, it is very easy to form a complex with metal ions, and this property makes it widely used in biomedicine and industrial fields. In the present invention, triethanolamine first participates in the dissolution-reconstruction process of vaterite to aragonite, and it complexes with the calcium ions dissolved by vaterite, slowing down the transformation rate, thereby reducing the water demand of the system, and then reducing the internal pores; in addition, during the reconstruction of aragonite, triethanolamine may be conducive to the growth of crystals along its radial direction, improve the aspect ratio of aragonite crystals, and enhance the mechanical interlocking effect; finally, after the triethanolamine is cured and dried in the test block, it can also fill the pores generated by water evaporation inside.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The organic filler material used in the present invention is not only compatible with other components in the cementitious material, but also can form a stable network structure during the drying process, effectively reduce pores, and improve the overall density and mechanical strength of the material. This improvement enables the material to perform well in engineering applications that bear heavy loads or require high durability.

[0024] The addition of organic fillers has significantly improved the mechanical properties of the new negative carbon cementitious material, which not only broadens its application scope, such as building structures, road construction, water conservancy projects, etc. These fields usually have high requirements on the mechanical properties of materials, and the materials of the present invention can meet these requirements.

[0025] The present invention solves the problem of insufficient mechanical properties of existing negative carbon type cementitious materials by adding organic fillers, and forms a new type of negative carbon type composite material. This technological innovation provides a new direction for the research and development of negative carbon materials and helps to promote the advancement of industry technology.

[0026] The method of the present invention is compatible with existing production processes and can be easily integrated into existing production lines without requiring large-scale modifications or adding additional production steps, which helps reduce the complexity and risks of technological transformation.

[0027] By filling the pores with organic filling materials, the material of the present invention exhibits better durability and stability during long-term use, reduces maintenance costs, and improves the economic benefits of the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1: Scanning electron microscopy images of the negative carbon composite materials obtained in Examples 1-3.

[0029] Figure 2 : Scanning electron microscope image of the negative carbon material obtained in Comparative Example 1. DETAILED DESCRIPTION

[0030] The following examples further illustrate the technical solution of the present invention, but are not intended to limit the scope of protection of the present invention.

[0031] Example

[0032] The present embodiment provides a negative carbon composite material, the components of which include vaterite calcium carbonate, magnesium salt, strontium salt, water, and organic filler material, wherein the vaterite calcium carbonate is prepared by the following method: using a bubbling method to pass 20% concentration CO2 gas into a calcium-rich solution (Ca 2+ After the reaction, the suspension was filtered and dried to obtain vaterite-type calcium carbonate.

[0033] A total of 4 groups of carbon-negative composite materials with different proportions were designed, numbered 1-1, 1-2, 1-3, and 1-4. The content of each component is given in mass fraction in Table 1.

[0034] The preparation process is as follows:

[0035] Dissolving magnesium salt and strontium salt in water to prepare a mixed solution containing magnesium ions and strontium ions, and then adding triethanolamine to the mixed solution containing magnesium ions and strontium ions, stirring and dispersing, to obtain a homogeneous mixed solution;

[0036] Add aragonite calcium carbonate into a stirring pot and stir, then add the above homogenized mixed solution and stir for 1 to 5 minutes until a slurry state appears;

[0037] The slurry was poured into a mold, vibrated to defoam, and a 20×20×20 mm test block was formed. After forming, it was placed at 90°C for steam curing for 1 hour and then demolded. The test block was placed in an oven at 105°C for drying for 8 hours to obtain a negative carbon composite material.

[0038] Comparative Example 1

[0039] Compared with the embodiments, no organic filling material is added in Comparative Example 1, and other components and steps are consistent with Embodiments 1-3.

[0040] Comparative Example 2

[0041] Compared with the embodiments, the organic filler material in Comparative Example 2 is changed to polypropylene glycol, and the amount of water used is the minimum amount of water for the slurry to produce rheological properties.

[0042] Comparative Example 3

[0043] Compared with the embodiments, in Comparative Example 3, the organic filler material is changed to chitosan, and the amount of water used is the minimum amount of water for the slurry to produce rheological properties.

[0044] Table 1 (unit of dosage: g)

[0045]

[0046] The strength and phase composition of the test blocks obtained in Example 1 are shown in Table 2.

[0047] Table 2

[0048]

[0049] As can be seen from the data in Table 2, after adding organic filler materials, a certain degree of strength improvement occurs relative to Comparative Example 1. When polypropylene glycol is used, the highest strength improvement is about 7%, but it is found in the experimental process that the addition of polyethylene glycol will cause the slurry to be creamy in the end, which is not conducive to molding. For chitosan, only mixing it with vaterite-type calcium carbonate and stirring it to form cannot achieve the high strength of natural shells, and it seems to induce the generation of some calcite. And triethanolamine shows the highest adaptability with the system. The addition of triethanolamine reduces the water demand of the system and reduces the porosity inside the test block after water evaporation, thereby greatly improving the mechanical properties of the test block (more than 60%). Although it also causes calcite formation, it does not seem to cause a reduction in mechanical properties. In addition, the types of magnesium salts and strontium salts do not seem to have a significant effect on material properties. Figure 1 and Figure 2 The scanning electron microscope images are respectively of Examples 1-3 and Comparative Example 1. Obviously, after the addition of triethanolamine, the aspect ratio of the aragonite crystal increases, which strengthens the mechanical interlocking effect between the crystals. In addition, the gel-like substance filling the internal pores of the test block may also be the reason for the increase in strength.

Claims

1. A carbon-negative composite material, Features The composition is calculated by weight as follows: 50-130 parts of vaterite calcium carbonate, 0.2-2.5 parts of magnesium salt, 1.0-4.5 parts of strontium salt, 10-70 parts of water, and 0.03-4 parts of organic filler; the organic filler is triethanolamine.

2. The negative carbon composite material according to claim 1, Features The magnesium salt is MgCl 2 and Mg(NO 3 ) 2 One or a mixture of.

3. The negative carbon composite material according to claim 1, Features The strontium salt is SrCl 2 and Sr(NO 3 ) 2 One or a mixture of.

4. The negative carbon composite material according to claim 1, Features Described vaterite type calcium carbonate is prepared in the following manner: Use the bubbling method to 2 The tail gas is passed into the calcium-rich solution after the salt is washed out with water to obtain a suspension containing calcium carbonate precipitation; The suspension is filtered and dried to obtain vaterite-type calcium carbonate.

5. The negative carbon composite material as claimed in claim 4, Features The calcium-rich solution is the filtrate obtained by washing and salt extraction of the bypass ash from the cooperative kiln, wherein Ca 2+ Concentration ≥0.05mol / L.

6. The negative carbon composite material according to claim 4, Features The CO 2 The tail gas is industrial flue gas, including CO 2 The concentration is 10vt%~37vt%.

7. The method for preparing the negative carbon composite material according to claim 1, Features The following steps are involved: (1) dissolving magnesium salt and strontium salt in water, adding organic filler material, stirring and dispersing, and obtaining a homogeneous mixed solution; (2) stirring and mixing the vaterite calcium carbonate and the above homogeneous mixed solution until a slurry state is formed; (3) pouring the slurry into a mold and curing it.

8. The method for preparing the negative carbon composite material according to claim 7, Features The curing conditions adopted in step 3 include: steam curing at 50-90° C. for 1-8 hours and then demolding; and drying at 90-130° C. for 8-20 hours to obtain a negative carbon composite material.

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