Solid waste-based filling plugging material and preparation method thereof

Abstract

The application discloses a solid waste-based filling plugging material and a preparation method thereof. The plugging material uses an organic additive. The organic additive forms a ternary enhanced network of "chelation dispersion-active site induction-interface bridging" through intermolecular synergistic effect, so that the prepared plugging material realizes mineralization-hydration synergistic enhancement.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and in particular to a solid waste-based filling and sealing material and its preparation method. Background Technology

[0002] With the rapid development of the coal industry, large quantities of coal-based solid waste, such as coal gangue and fly ash, have accumulated, not only occupying land resources but also polluting the environment. Using coal-based solid waste to prepare filling and sealing materials is one of the important ways to achieve the resource utilization of solid waste.

[0003] Currently, commonly used solid waste-based filling and sealing materials mainly rely on the hydration of cement to achieve bonding, but the simple hydration process has problems such as low early strength and insufficient durability. Summary of the Invention

[0004] This application provides a solid waste-based filling and sealing material and its preparation method. The sealing material uses an organic additive, which forms a ternary reinforcing network of "chelation dispersion-active site induction-interfacial bridging" through intermolecular synergistic effects, so that the prepared sealing material achieves synergistic enhancement of mineralization and hydration.

[0005] In a first aspect, the present invention provides a solid waste-based filling and sealing material, the solid waste-based filling and sealing material comprising the following components: coal-based solid waste, cement and organic additives; wherein the organic additives comprise the following components: carboxymethyl chitosan, polyethylene glycol-modified maleic anhydride copolymer and glucosamine-modified acrylate copolymer.

[0006] In some embodiments, the components of the solid waste-based filling and sealing material include, by mass, 70-90 parts of coal-based solid waste, 5-15 parts of cement, and 1-3 parts of organic additives.

[0007] In some embodiments, the coal-based solid waste includes at least one substance selected from coal gangue and fly ash.

[0008] In some embodiments, the mass ratio of carboxymethyl chitosan, polyethylene glycol-modified maleic anhydride copolymer, and glucosamine-modified acrylate copolymer in the organic additive is 5:3:2.

[0009] Secondly, the present invention provides a method for preparing a solid waste-based filling and sealing material, comprising:

[0010] Coal-based solid waste is crushed to a preset particle size to obtain coal-based solid waste powder;

[0011] Preparation of organic additives;

[0012] The coal-based solid waste powder, cement, and organic additives are added to a mixer and stirred evenly to obtain a mixture; water is added to the mixture and stirred until a uniform slurry is formed; wherein the weight of the water is 10%-20% of the weight of the mixture.

[0013] The slurry is placed in a sealed container and mineralized by introducing carbon dioxide gas to obtain a solid waste-based filling and sealing material.

[0014] In some embodiments, the step of preparing the organic additive includes:

[0015] Carboxymethyl chitosan, polyethylene glycol-modified maleic anhydride copolymer, and glucosamine-modified acrylate copolymer were prepared.

[0016] In some embodiments, the step of preparing carboxymethyl chitosan includes:

[0017] Chitosan is added to a sodium hydroxide solution with a mass fraction of 20%-30% and stirred until dissolved to obtain a chitosan alkaline solution.

[0018] After adding 10 ml of chloroacetic acid to the chitosan alkaline solution, react at 50-60℃ for 2-3 h;

[0019] After the reaction was completed, the reaction solution was poured into ethanol, and after precipitation, filtration, washing and drying, carboxymethyl chitosan was obtained.

[0020] In some embodiments, the step of preparing the polyethylene glycol-modified maleic anhydride copolymer includes:

[0021] Maleic anhydride and polyethylene glycol were added to a reactor at a molar ratio of 1:1-2 and reacted at 120-140℃ for 3-4 hours under nitrogen protection to obtain a polyethylene glycol-modified maleic anhydride copolymer.

[0022] In some embodiments, the step of preparing the glucosamine-modified acrylate copolymer includes:

[0023] Acrylate, glucosamine, and benzoyl peroxide were added to toluene in a mass ratio of 10:1:0.1 and reacted at 60-80℃ for 4-5 hours.

[0024] After the reaction was completed, toluene was removed by distillation to obtain glucosamine-modified acrylate copolymer.

[0025] In some embodiments, the pressure of the carbon dioxide gas introduced is 0.1-0.3 MPa; the temperature of the mineralization modification is 20-40°C, and the mineralization time is 20-60 min.

[0026] This invention provides a solid waste-based filling and sealing material and its preparation method. The sealing material uses an organic additive, which forms a ternary reinforcing network of "chelation dispersion-active site induction-interfacial bridging" through intermolecular synergistic effects, thereby enabling the prepared sealing material to achieve synergistic enhancement of mineralization and hydration. Attached Figure Description

[0027] Figure 1 A flowchart illustrating a method for preparing a solid waste-based filling and sealing material according to some embodiments is provided. Detailed Implementation

[0028] To better understand the above technical solutions, the technical solutions of this application will be described in detail below through specific implementation methods.

[0029] With the rapid development of the coal industry, large quantities of coal-based solid waste, such as coal gangue and fly ash, have accumulated, not only occupying land resources but also polluting the environment. Using coal-based solid waste to prepare filling and sealing materials is one of the important ways to achieve the resource utilization of solid waste.

[0030] Currently, commonly used solid waste-based backfill and sealing materials mainly rely on the hydration of cement to achieve bonding. However, simple hydration results in problems such as low early strength and insufficient durability. Furthermore, traditional CO2 mineralization technologies often use curing chambers, which have low mineralization efficiency and incomplete reactions. Existing organic admixtures still have shortcomings in synergistically improving mineralization enhancement and bonding performance, and some admixtures have complex preparation methods and high costs.

[0031] To address the aforementioned technical problems, this application provides a solid waste-based filling and sealing material and its preparation method. The sealing material uses an organic additive, which forms a ternary reinforcing network of "chelation dispersion-active site induction-interfacial bridging" through intermolecular synergistic effects, enabling the prepared sealing material to achieve synergistic enhancement of mineralization and hydration.

[0032] This application provides a solid waste-based backfilling and sealing material, comprising the following components: coal-based solid waste, cement, and organic additives; wherein the organic additives comprise the following components: carboxymethyl chitosan, polyethylene glycol-modified maleic anhydride copolymer, and glucosamine-modified acrylate copolymer. The coal-based solid waste includes at least one substance selected from coal gangue and fly ash.

[0033] In this embodiment of the application, in the solid waste-based filling and sealing material system, the three components of the organic additive form a ternary enhanced network of "chelation dispersion-active site induction-interfacial bridging" through intermolecular synergistic effects. Its interaction mechanism with coal-based solid waste and cement exhibits the following hierarchical synergistic effect:

[0034] 1. The molecular-level synergistic effect among the three components in the organic additive.

[0035] Hydrogen-bonded association (i.e., chelate dispersion) of carboxymethyl chitosan and polyethylene glycol-modified maleic anhydride copolymer: The carboxyl groups (-COOH) on the carboxymethyl chitosan molecular chain and the ether bonds (-O-) in the polyethylene glycol-modified maleic anhydride copolymer form a flexible network structure through hydrogen bonding. This spatial network, on the one hand, encapsulates cement particles to slow down the hydration rate (buying time for the mineralization reaction), and on the other hand, improves the fluidity of the slurry formed by coal-based solid waste powder, cement and organic additives (the specific formation process of this slurry is described below) through the steric hindrance effect, making the CO2 bubbles more uniformly distributed in the slurry (the average bubble size is reduced from 50 μm in the traditional system to below 20 μm).

[0036] Interfacial anchoring effect of glucosamine-modified acrylate copolymers: The amino groups (-NH2) of glucosamine-modified acrylate copolymers can form ionic bonds with the carboxyl groups of carboxymethyl chitosan, while the ester groups (-COO-) undergo polar adsorption with the carboxyl groups of polyethylene glycol-modified maleic anhydride copolymers, forming a "core-shell" adsorption layer (i.e., active site induction) on the surface of coal-based solid waste particles. The core glucosamine-modified acrylate copolymer forms covalent bonds through condensation reactions between the amino groups and the surface silanol groups (-SiOH) of coal-based solid waste, while the outer shell carboxymethyl chitosan-polyethylene glycol-modified maleic anhydride copolymer complex encapsulates the particles through hydrogen bonding and electrostatic interactions (i.e., interfacial bridging), increasing the surface hydrophilicity of coal-based solid waste particles by 30% and significantly enhancing the activity of CO2 mineralization reaction.

[0037] 2. Hydration regulation mechanism of admixtures and cement

[0038] Calcium ion chelation-sustaining effect of carboxymethyl chitosan: The carboxyl group of carboxymethyl chitosan reacts with calcium ions... 2+ A five-membered ring chelate [Ca(CC)2] is formed. 2- Ca in the initial stage of cement hydration 2+ The reduced concentration slows down the rapid formation of ettringite and CSH gel, reserving more calcium hydroxide for subsequent mineralization reactions.

[0039] Directional guidance of hydration products of polyethylene glycol-modified maleic anhydride copolymer: The long-chain ether groups of polyethylene glycol-modified maleic anhydride copolymer are adsorbed on the surface of CSH gel (which is generated from cement after adding water), which promotes the transformation of the gel from an amorphous structure to fibrous crystals. This oriented growth of the gel network and the mineralized calcite crystals form an interlocking structure of "cement hydration crystal nucleus-mineralized crystal".

[0040] 3. Mineralization enhancement mechanism of admixtures and coal-based solid waste

[0041] Multiplication effect of active sites in glucosamine-modified acrylate copolymers: The glucosamine residues in glucosamine-modified acrylate copolymer molecules contain free amino groups, which act as CO adsorption sites during mineralization, promoting carbon fixation through the following reactions:

[0042] -NH2 + CO2 + H2O → -NH3 + +HCO3 -

[0043] The generated HCO3- reacts with the Ca released during cement hydration. 2+ The reaction produces calcium carbonate, increasing the carbon fixation capacity by 20%-30% compared to a single additive system.

[0044] In some embodiments, the components of the solid waste-based filling and sealing material, by mass, include: 70-90 parts coal-based solid waste, 5-15 parts cement, and 1-3 parts organic admixtures. The reason for setting the component percentages in this embodiment is that if the coal-based solid waste exceeds 90 parts, it will prevent the required strength for filling and sealing from being achieved regardless of mineralization and hydration; if it is too low, the amount of other components may need to be increased, leading to excessive costs. A cement content increases the cost of the sealing material, while a low content will not achieve the required strength. Both excessively high and low amounts of organic admixtures will not achieve the desired mineralization enhancement effect, and excessive amounts will also increase costs.

[0045] In some embodiments, the mass ratio of carboxymethyl chitosan, polyethylene glycol-modified maleic anhydride copolymer, and glucosamine-modified acrylate copolymer in the organic additive is 5:3:2.

[0046] In this embodiment, the mass ratio of 5:3:2 allows carboxymethyl chitosan, polyethylene glycol-modified maleic anhydride copolymer, and glucosamine-modified acrylate copolymer to exert a better synergistic enhancement effect. Deviations from this ratio will result in a significant reduction in the synergistic effect.

[0047] This application also provides a method for preparing a solid waste-based filling and sealing material. Figure 1 A flowchart illustrating an exemplary method for preparing a solid waste-based filling and sealing material according to some embodiments is provided. The method includes steps S100-S400.

[0048] S100. The coal-based solid waste is crushed to a preset particle size to obtain coal-based solid waste powder.

[0049] In some embodiments, the preset particle size is less than 0.1 mm, so that the resulting coal-based solid waste powder can react sufficiently with other components.

[0050] S200, Preparation of organic additives.

[0051] In some embodiments, the step of preparing the organic additive includes:

[0052] Carboxymethyl chitosan, polyethylene glycol-modified maleic anhydride copolymer, and glucosamine-modified acrylate copolymer were prepared.

[0053] In some embodiments, the step of preparing carboxymethyl chitosan includes:

[0054] Chitosan is added to a sodium hydroxide solution with a mass fraction of 20%-30% and stirred until dissolved to obtain a chitosan alkaline solution.

[0055] After adding 10 ml of chloroacetic acid to the chitosan alkaline solution, react at 50-60℃ for 2-3 h;

[0056] After the reaction was completed, the reaction solution was poured into ethanol, and after precipitation, filtration, washing and drying, carboxymethyl chitosan was obtained.

[0057] In this embodiment, the preparation of carboxymethyl chitosan based on the above process parameters can maximize the generation of carboxymethyl chitosan and reduce the generation of byproducts such as carboxyethyl or propyl chitosan. Exceeding the above process description will lead to the generation of a large number of byproducts.

[0058] In some embodiments, the step of preparing the polyethylene glycol-modified maleic anhydride copolymer includes:

[0059] Maleic anhydride and polyethylene glycol were added to a reactor at a molar ratio of 1:1-2 and reacted at 120-140℃ for 3-4 hours under nitrogen protection to obtain a polyethylene glycol-modified maleic anhydride copolymer.

[0060] In some embodiments, the step of preparing the glucosamine-modified acrylate copolymer includes:

[0061] Acrylate, glucosamine, and benzoyl peroxide were added to toluene in a mass ratio of 10:1:0.1 and reacted at 60-80℃ for 4-5 hours.

[0062] After the reaction was completed, toluene was removed by distillation to obtain glucosamine-modified acrylate copolymer.

[0063] S300. The coal-based solid waste powder, cement, and organic additives are added to a mixer and stirred evenly to obtain a mixture; water is added to the mixture and stirred until a uniform slurry is formed; wherein the weight of the water is 10%-20% of the weight of the mixture.

[0064] In this embodiment, the water weight is set at 10%-20% of the weight of the mixture because the water addition within this range can maintain good fluidity and strength of the slurry. Excessive water addition, although it gives the slurry a good concentration, requires the addition of more cement or more additives to maintain the same strength; while insufficient water addition will reduce the fluidity of the slurry and make it difficult to pump.

[0065] S400. The slurry is placed in a sealed container, and carbon dioxide gas is introduced to carry out mineralization modification to obtain a solid waste-based filling and sealing material.

[0066] In some embodiments, the carbon dioxide gas is introduced at a pressure of 0.1-0.3 MPa; the mineralization modification temperature is 20-40°C, and the mineralization time is 20-60 min. These process parameters result in the best mineralization enhancement effect.

[0067] The solid waste-based filling and sealing material in this embodiment is a solid waste-based filling and sealing material that is synergistically enhanced by mineralization and hydration.

[0068] The composition of the solid waste-based filling and sealing material is described in tabular form in Table 1, where cc represents carboxymethyl chitosan, AGA represents glucosamine-modified acrylate copolymer, and PEG-MA represents polyethylene glycol-modified maleic anhydride copolymer. Single, binary, and ternary components represent the types of organic additives used. Mixed solid waste refers to coal-based solid waste including both coal gangue and fly ash. The examples and comparative examples are identical in all preparation process parameters except for the raw materials.

[0069] Table 1

[0070]

[0071]

[0072] As shown in Table 1, the carbon fixation content (28%) of the ternary system in Example 1 was higher than that of Comparative Example 1 (without admixture) when the cement content was only 5 parts, proving that the synergistic effect of admixtures can still effectively promote mineralization under low cement content.

[0073] A comparison of Example 1 (with all three admixtures added) and Comparative Examples 2-6 (with single / binary admixtures) shows that although the ternary system has the lowest cement content (5 parts), its carbon fixation content (28%) is still higher than that of Comparative Examples 2-6. This indicates that the three admixtures achieve "high-performance cementation with low cement content" through a quadruple mechanism of "delayed hydration, controlled crystal form, enhanced mineralization, and interfacial bonding," breaking through the limitations of traditional systems that rely on high cement content.

[0074] In summary, the present invention provides a solid waste-based filling and sealing material and its preparation method. The sealing material uses an organic additive, which forms a ternary reinforcing network of "chelation dispersion-active site induction-interfacial bridging" through intermolecular synergistic effects, thereby enabling the prepared sealing material to achieve synergistic enhancement of mineralization and hydration.

[0075] It will be readily understood by those skilled in the art that the above-described advantageous methods can be freely combined and superimposed without conflict. The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A solid waste-based filling and sealing material, characterized in that, The solid waste-based filling and sealing material comprises the following components: coal-based solid waste, cement, and organic additives; wherein the organic additives comprise the following components: carboxymethyl chitosan, polyethylene glycol-modified maleic anhydride copolymer, and glucosamine-modified acrylate copolymer.

2. The solid waste-based filling and sealing material according to claim 1, characterized in that, The solid waste-based filling and sealing material comprises, by weight, 70-90 parts coal-based solid waste, 5-15 parts cement, and 1-3 parts organic additives.

3. The solid waste-based filling and sealing material according to claim 1, characterized in that, The coal-based solid waste includes at least one substance from coal gangue and fly ash.

4. The solid waste-based filling and sealing material according to claim 1, characterized in that, The mass ratio of carboxymethyl chitosan, polyethylene glycol-modified maleic anhydride copolymer, and glucosamine-modified acrylate copolymer in the organic additive is 5:3:

2.

5. The method for preparing the solid waste-based filling and sealing material according to any one of claims 1-4, characterized in that, include: Coal-based solid waste is crushed to a preset particle size to obtain coal-based solid waste powder; Preparation of organic additives; The coal-based solid waste powder, cement, and organic additives are added to a mixer and stirred until homogeneous to obtain a mixture; water is added to the mixture and stirred until a homogeneous slurry is formed; wherein the weight of the water is 10%-20% of the weight of the mixture; The slurry is placed in a sealed container and mineralized by introducing carbon dioxide gas to obtain a solid waste-based filling and sealing material.

6. The method according to claim 5, characterized in that, The steps for preparing the organic additive include: Carboxymethyl chitosan, polyethylene glycol-modified maleic anhydride copolymer, and glucosamine-modified acrylate copolymer were prepared.

7. The method according to claim 6, characterized in that, The steps for preparing carboxymethyl chitosan include: Chitosan is added to a sodium hydroxide solution with a mass fraction of 20%-30% and stirred until dissolved to obtain a chitosan alkaline solution. After adding 10 ml of chloroacetic acid to the chitosan alkaline solution, react at 50-60℃ for 2-3 h; After the reaction was completed, the reaction solution was poured into ethanol, and after precipitation, filtration, washing and drying, carboxymethyl chitosan was obtained.

8. The method according to claim 6, characterized in that, The steps for preparing the polyethylene glycol-modified maleic anhydride copolymer include: Maleic anhydride and polyethylene glycol were added to a reactor at a molar ratio of 1:1-2 and reacted at 120-140℃ for 3-4 hours under nitrogen protection to obtain a polyethylene glycol-modified maleic anhydride copolymer.

9. The method according to claim 6, characterized in that, The steps for preparing the glucosamine-modified acrylate copolymer include: Acrylate, glucosamine, and benzoyl peroxide were added to toluene in a mass ratio of 10:1:0.1 and reacted at 60-80℃ for 4-5 hours. After the reaction was completed, toluene was removed by distillation to obtain glucosamine-modified acrylate copolymer.

10. The method according to claim 6, characterized in that, The carbon dioxide gas is introduced at a pressure of 0.1-0.3 MPa; the mineralization modification temperature is 20-40℃, and the mineralization time is 20-60 min.

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