A waste disposal additive, its preparation method and application

Abstract

This invention provides a slag disposal additive, its preparation method, and its application, belonging to the field of soil solidification. By weight, the additive comprises 0.1-5 parts of nano-silica, 40-60 parts of epoxy resin, 10-60 parts of a moisture-curing agent, 5-20 parts of microcapsules, 0.01-0.1 parts of surfactant, and 0.1-1 parts of carbon nanotubes. The preparation method involves mixing nano-silica and epoxy resin according to the above proportions, adding carbon nanotubes, and ultrasonically dispersing to obtain a mixture; encapsulating the moisture-curing agent in microcapsules, adding the encapsulated microcapsules and surfactant to the mixture, and mixing thoroughly; alternatively, a small amount of moisture-curing agent can be added during the preparation of the mixture. This additive is used in conjunction with inorganic components. After solidification, the slag exhibits high strength, good uniformity, strong stability, good frost resistance, and low carbon emissions.

Description

Technical Field

[0001] This invention relates to the field of slag solidification, and in particular to a slag disposal additive, its preparation method, and its application. Background Technology

[0002] With the development of infrastructure in my country, more and more cities are using the shield tunneling method to construct underground projects. Shield tunneling excavation soil has become the main source of waste in urban construction, posing a significant challenge to the urban environment. Currently, the main method for disposing of shield tunneling excavation soil is landfilling. This method requires transporting the excavation soil to landfills, which easily leads to road spillage and environmental pollution. Landfilling also requires the use of large areas of land.

[0003] Current technologies generally involve adding a solidifying agent to the slag to break the water film on the slag surface, reduce the water absorption of particles, and increase water repellency. Through a series of treatment processes such as activation and compaction, the slag is solidified, which significantly enhances the overall performance of the structure, such as density and water resistance, thereby improving the strength and load-bearing capacity of the structure.

[0004] Existing soil stabilizers mostly use materials such as cement and fly ash, which require large quantities. The resulting stabilized soil has poor uniformity and low strength, and the production process generates a large amount of carbon emissions, resulting in poor environmental performance. In addition, the geological conditions traversed during shield tunneling are complex, and the resulting excavated soil has a variety of mineral types and complex chemical compositions. Existing soil stabilizers are unable to stabilize shield tunnel excavated soil, resulting in a considerable portion of shield tunnel excavated soil having to be transported off-site and disposed of, causing a large amount of resource waste and environmental pollution.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a waste disposal additive, its preparation method, and its application.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] As a first aspect of the present invention, the present invention provides a slag disposal additive, comprising, by weight, 0.1-5 parts of nano-silica, 40-60 parts of epoxy resin, 10-60 parts of moisture-curing agent, 5-20 parts of microcapsules, 0.01-0.1 parts of surfactant and 0.1-1 parts of carbon nanotubes, etc.

[0009] Nano-silica has small particle size and high surface activity, and can be synergistically cured with epoxy resin.

[0010] Preferably, the epoxy resin is a bisphenol A type epoxy resin.

[0011] Preferably, the moisture-curing curing agent includes ketimine or methoxysilane. The moisture-curing curing agent can react with epoxy resin to form polymeric network-structured cement particles.

[0012] Preferably, the microcapsules are soluble in alkaline environments. The microcapsules comprise one or more of the following: acrylic polymers, acrylate polymers, hexose polymers, or methyl galacturonic acid esters.

[0013] Preferably, the moisture-curing curing agent is encapsulated in the microcapsule.

[0014] The microcapsules encapsulate a moisture-curing curing agent. When the capsules encounter alkaline substances such as cement or lime, they dissolve, releasing the moisture-curing curing agent to react with the epoxy resin.

[0015] Preferably, the surfactant includes one or more of polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, or polyacrylamide, which can improve the fluidity of the slag slurry.

[0016] As a second aspect of the present invention, the present invention also provides a method for preparing the aforementioned slag disposal additive, comprising at least the following steps in sequence: mixing 0.1-5 parts of nano-silica with 40-60 parts of epoxy resin, adding 0.1-1 parts of carbon nanotubes for ultrasonic dispersion to obtain a mixture; encapsulating 10-60 parts of a moisture-curing curing agent in 5-20 parts of microcapsules, adding the encapsulated microcapsules and 0.01-0.1 parts of a surfactant to the mixture, mixing evenly to obtain the slag disposal additive.

[0017] As a third aspect of the present invention, the present invention also provides a technical solution parallel to the second aspect, namely, a method for preparing the aforementioned slag disposal additive, comprising at least the following steps: mixing 0.1-5 parts of nano-silica, 40-60 parts of epoxy resin, and 1-3 parts of a wet-curing curing agent; adding 0.1-1 parts of carbon nanotubes and ultrasonically dispersing to obtain a mixture; encapsulating 7-59 parts of the wet-curing curing agent in 5-20 parts of microcapsules; adding the encapsulated microcapsules and 0.01-0.1 parts of a surfactant to the mixture and mixing evenly to obtain the slag disposal additive. Adding a small amount of wet-curing curing agent outside the microcapsules allows for pre-curing with the epoxy resin to form a certain amount of polymeric network structure cemented soil particles. Furthermore, the large amount of wet-curing curing agent released from the microcapsules acts as a bridge in the reaction process, forming a larger and more stable network structure.

[0018] As a fourth aspect of the present invention, the present invention also provides an application of the aforementioned slag disposal additive: the slag disposal additive is used in combination with an alkaline inorganic component.

[0019] The inorganic component includes one or more of cement, lime, or slag. The inorganic component forms an alkaline environment upon contact with water, promoting the dissolution of the microcapsules, and it can also interact with epoxy resin and nano-SiO2 to form a gelling substance.

[0020] The aforementioned waste soil treatment additive is used in conjunction with inorganic components such as cement. When these inorganic components encounter water, they undergo a hydration reaction to form a gelling substance. These hydration products encapsulate soil particles, transforming them from dispersed small particles into aggregated large particles, thereby increasing the strength of the waste soil. The hydroxyl groups of the epoxy resin in the additive adsorb calcium ions, reducing the concentration of calcium ions in the solution and promoting the ionization process of inorganic components such as cement, ultimately leading to a decrease in the calcium ion concentration in the solution. 2+ OH - Excessive. The nano-SiO2 in the aforementioned slag disposal additive contains poorly polymerized Si-O tetrahedra. In an alkaline environment, upon contact with water in the slurry, the bonding of these Si-O tetrahedra weakens, eventually causing them to dissolve and transform into H3SiO. - It takes on a form and enters the solution, and once it encounters calcium ions, it readily forms hydrated calcium silicate gel.

[0021] In this invention, more gel material is generated through the combined action of epoxy resin and nano-SiO2. Nano-SiO2 possesses excellent surface properties such as small average particle size and large specific surface area, enabling it to effectively adsorb Ca from within the solidified soil. 2+ And because of the adsorption of Ca 2+ Subsequently, the hydration rates of C2S, C3A, and C3S within the solidified soil accelerate. On the other hand, the dispersing effect of nano-SiO2 results in a more uniform particle distribution within the solidified soil, allowing more unreacted particles to come into contact with water and react, thus increasing the overall hydration level of the solidified soil. The combination of these two factors deepens the hydration process within the solidified soil, generating more hydration products. This causes large pores between particles to become smaller and eventually disappear, thereby enhancing the performance of the solidified soil. The resulting solidified soil exhibits high strength, good uniformity, strong stability, good frost resistance, and low carbon emissions.

[0022] Carbon nanotubes play a reinforcing and toughening role, and their interaction with epoxy resin film and hydration products at the nanoscale prevents cracking of the solidified slag and enhances the strength of the solidified slag. Detailed Implementation

[0023] As used in this article:

[0024] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0025] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0026] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0027] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass. It is important to understand that, unlike the number of parts by mass, the sum of the parts by mass of all components is not limited to 100 parts.

[0028] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0029] The embodiments of the present invention will be described in detail below with reference to specific examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0030] In the following examples and comparative examples, different soil types were used to test the application of the slag disposal additive. The test items were 7-day unconfined compressive strength, 4-hour setting time influence coefficient, water stability coefficient, and 28-day frost resistance.

[0031] Example 1

[0032] An additive for treating construction waste includes 3 kg of nano-silica, 50 kg of bisphenol A type epoxy resin, 20 kg of methoxysilane, 8 kg of acrylate polymer (polymethyl acrylate), 50 g of polyvinyl alcohol and 200 g of carbon nanotubes.

[0033] The preparation method involves mixing 3 kg of nano-silica and 50 kg of bisphenol A epoxy resin, adding 200 g of carbon nanotubes, and dispersing the mixture evenly under ultrasonication. Then, 20 kg of methoxysilane and 8 kg of acrylate polymer (polymethyl acrylate) are centrifuged and extruded to obtain encapsulated microcapsules. Finally, the encapsulated microcapsules and 50 g of polyvinyl alcohol are added to the above mixture and stirred evenly to obtain the final product.

[0034] The application method involves first thoroughly mixing 5 tons of cement with 15 tons of soil, then mixing the slag disposal additive with 1 ton of water to form a solution. This solution is then sprayed onto the surface of the cement-mixed soil. Finally, the soil is stirred evenly in several molds and allowed to solidify. Its test performance is shown in Table 1.

[0035] Example 2

[0036] An additive for treating construction waste includes 1 kg of nano-silica, 40 kg of bisphenol A type epoxy resin, 30 kg of ketimine, 15 kg of acrylic polymer (polyacrylic acid), 100 g of polyacrylic acid and 300 g of carbon nanotubes.

[0037] The preparation method involves mixing 1 kg of nano-silica and 40 kg of bisphenol A epoxy resin, adding 300 g of carbon nanotubes, and dispersing the mixture evenly under ultrasonication. Then, 30 kg of ketimine and 15 kg of acrylic polymer (polyacrylic acid) are centrifuged and extruded to obtain encapsulated microcapsules. Finally, the encapsulated microcapsules and 100 g of polyacrylic acid are added to the above mixture and stirred evenly to obtain the final product.

[0038] The application method involves first thoroughly mixing 5 tons of lime with 15 tons of soil, then mixing the slag disposal additive with 1 ton of water to form a solution. This solution is then sprayed onto the surface of the soil mixed with lime. Finally, the soil is stirred evenly in several molds and allowed to solidify. Its test performance is shown in Table 1.

[0039] Example 3

[0040] An additive for treating construction waste includes 5 kg of nano-silica, 60 kg of bisphenol A type epoxy resin, 50 kg of methoxysilane, 20 kg of acrylate polymer (polymethyl acrylate), 20 g of polyvinyl alcohol and 700 g of carbon nanotubes.

[0041] The preparation method involves mixing 5 kg of nano-silica and 60 kg of bisphenol A epoxy resin, adding 700 g of carbon nanotubes, and dispersing the mixture uniformly under ultrasonication. Then, 50 kg of methoxysilane and 20 kg of acrylate polymer (polymethyl acrylate) are centrifuged and extruded to obtain encapsulated microcapsules. Finally, the encapsulated microcapsules and 20 g of polyvinyl alcohol are added to the above mixture and stirred until homogeneous to obtain the final product.

[0042] The application method involves first thoroughly mixing 5 tons of cement with 15 tons of soil, then mixing the slag disposal additive with 1 ton of water to form a solution. This solution is then sprayed onto the surface of the cement-mixed soil. Finally, the soil is stirred evenly in several molds and allowed to solidify. Its test performance is shown in Table 1.

[0043] Example 4

[0044] An additive for treating construction waste includes 3 kg of nano-silica, 50 kg of bisphenol A type epoxy resin, 20 kg of methoxysilane, 8 kg of acrylate polymer (polymethyl acrylate), 50 g of polyvinyl alcohol and 200 g of carbon nanotubes.

[0045] The preparation method involves mixing 3 kg of nano-silica, 50 kg of bisphenol A epoxy resin, and 1 kg of methoxysilane, then adding 200 g of carbon nanotubes and dispersing the mixture uniformly under ultrasonication. 19 kg of methoxysilane and 8 kg of acrylate polymer (polymethyl acrylate) are then centrifuged and extruded to obtain encapsulated microcapsules. Subsequently, the encapsulated microcapsules and 50 g of polyvinyl alcohol are added to the above mixture and stirred until homogeneous to obtain the final product.

[0046] The application method involves first thoroughly mixing 5 tons of cement with 15 tons of soil, then mixing the slag disposal additive with 1 ton of water to form a solution. This solution is then sprayed onto the surface of the cement-mixed soil. Finally, the soil is stirred evenly in several molds and allowed to solidify. Its test performance is shown in Table 1.

[0047] Comparative Example 1

[0048] The difference from Example 1 is that ordinary silica was used instead of nano silica, and its test performance is shown in Table 1.

[0049] Comparative Example 2

[0050] An additive for treating construction waste includes 3 kg of nano-silica, 50 kg of bisphenol A type epoxy resin, 20 kg of methoxysilane, 50 g of polyvinyl alcohol and 200 g of carbon nanotubes.

[0051] The preparation method involves mixing 3 kg of nano-silica and 50 kg of bisphenol A epoxy resin, adding 200 g of carbon nanotubes, and dispersing the mixture evenly under ultrasonication. Then, 20 kg of methoxysilane and 50 g of polyvinyl alcohol are added to the mixture and stirred until homogeneous to obtain the final product.

[0052] The application method involves first thoroughly mixing 5 tons of cement with 15 tons of soil, then mixing the slag disposal additive with 1 ton of water to form a solution. This solution is then sprayed onto the surface of the cement-mixed soil. Finally, the soil is stirred evenly in several molds and allowed to solidify. Its test performance is shown in Table 1.

[0053] Table 1. Performance Comparison of Examples and Comparative Examples

[0054]

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0056] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of the invention and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A waste disposal additive, characterized in that, According to the weight parts, it includes 0.1-5 parts of nano-silica, 40-60 parts of epoxy resin, 10-60 parts of moisture-curing agent, 5-20 parts of microcapsules, 0.01-0.1 parts of surfactant and 0.1-1 parts of carbon nanotubes.

2. The slag disposal additive according to claim 1, characterized in that, The epoxy resin is a bisphenol A type epoxy resin.

3. The slag disposal additive according to claim 1, characterized in that, The moisture-curing type curing agent includes ketimine or methoxysilane.

4. The slag disposal additive according to claim 1, characterized in that, The microcapsules comprise one or more of acrylic polymers, acrylate polymers, hexose polymers, or methyl galacturonic acid esters.

5. The slag disposal additive according to claim 1, characterized in that, The surfactant includes one or more of polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, or polyacrylamide.

6. The slag disposal additive according to claim 1, characterized in that, The moisture-curing agent is encapsulated in the microcapsule.

7. A method for preparing the slag disposal additive according to any one of claims 1-6, characterized in that, The process includes at least the following steps: mixing 0.1-5 parts of nano-silica with 40-60 parts of epoxy resin, adding 0.1-1 parts of carbon nanotubes and ultrasonically dispersing the mixture; encapsulating 10-60 parts of wet-curing curing agent in 5-20 parts of microcapsules, adding the encapsulated microcapsules and 0.01-0.1 parts of surfactant to the mixture, and mixing evenly to obtain the slag disposal additive.

8. A method for preparing a slag disposal additive according to any one of claims 1-6, characterized in that, The process includes at least the following steps: mixing 0.1-5 parts of nano-silica, 40-60 parts of epoxy resin and 1-3 parts of wet-curing curing agent; adding 0.1-1 parts of carbon nanotubes and ultrasonically dispersing the mixture to obtain a mixture; encapsulating 7-59 parts of wet-curing curing agent in 5-20 parts of microcapsules; adding the encapsulated microcapsules and 0.01-0.1 parts of surfactant to the mixture and mixing evenly to obtain the slag disposal additive.

9. The application of the slag disposal additive according to any one of claims 1-6, characterized in that, The waste disposal additive is used in combination with inorganic components.

10. The application of the slag disposal additive according to claim 9, characterized in that, The inorganic component includes one or more of cement, lime, or slag.

Images