A marine mud stabilizer and its preparation method

Abstract

This invention discloses a marine mud stabilizer and its preparation method. The marine mud stabilizer, by weight, comprises: 5-32 parts of fluorinated biochar, 10-70 parts of polyvinyl acetate, 1-13 parts of boric acid, 0.5-8 parts of silane coupling agent, 0.5-5 parts of organosilicon-polyether block copolymer, and 50-300 parts of solvent. This invention utilizes the synergistic effect of fluorinated biochar, polyvinyl acetate, boric acid, silane coupling agent, and organosilicon-polyether block copolymer to prepare a liquid marine mud stabilizer that can reduce the salt ion concentration and organic matter content of marine mud, and improve its mechanical properties and water stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of soil solidification and stabilization, in particular to a marine mud stabilizer and a preparation method thereof. BACKGROUND

[0002] High-salinity and high-organic marine mud is widely distributed in coastal beaches, estuary deltas and near-shore shallow sea areas, and is formed by long-term marine sedimentation. Its physical and mechanical properties are extremely special. Not only is the void ratio greater than 1.5, but also it is rich in movable Cl - , SO4² - salinity ions (salt content conductivity ≥ 7 mS / cm) due to seawater immersion. At the same time, the deposition process enriches planktonic residues and humus, etc., making the organic matter content as high as 13%~20%. These characteristics result in loose structure, strong compressibility and extremely low strength of marine mud. When directly used as an engineering foundation, it is extremely easy to cause uneven settlement, insufficient bearing capacity and other problems, which seriously threatens the safety of structures such as road engineering, and may even lead to engineering rework or abandonment.

[0003] In view of this problem, marine mud solidification modification has become the core solution in engineering construction. The technical essence is to add a stabilizer to the marine mud, and through a series of physical and chemical reactions such as adsorption, wrapping, hydration and cross-linking reaction between the stabilizer and the water, colloidal particles and active components in the marine mud, a continuous and stable cementation structure is finally formed, thereby effectively reducing the water content of the marine mud and significantly improving its mechanical properties such as compressive strength and shear strength. The existing solidification agent has obvious technical shortcomings for high-salinity and high-organic marine mud, which is specifically manifested as follows:

[0004] (1) The existing solidification agent is not optimized for high-concentration Cl - , SO4² - environment. The reaction between it and the cementing components generates easily soluble or swelling products, which destroys the double electric layer balance of marine mud particles, resulting in strength decay and structure disintegration of the solidified body in water environment, and significantly low water stability.

[0005] (2) Humus and other organic matters in marine mud form a dense wrapping layer on the surface of the particles, which hinders the effective contact of the solidification agent. Their active groups compete with the active sites of the solidification agent for binding, significantly inhibiting the cementation reaction. The existing organic solidification agent lacks a synergistic cementation mechanism, and the solidified body is easy to disintegrate due to swelling of the organic matter.

[0006] (3) Many agents on the market excessively rely on a single hydrophobic component, resulting in high porosity of the solidified body. Excessive use of hydrophilic components can easily cause erosion problems. Moreover, the organic-inorganic interface has poor compatibility, lacks an efficient coupling mechanism, and the solidified body often appears to be layered and damaged, making it difficult to simultaneously improve water stability and mechanical properties.

[0007] (4) The existing curing agent adopts a single solvent system, which causes aggregation of the initiation component and insufficient reaction, and the curing effect only stays on the surface; in the water environment for a long time, the unreacted component flows out, further exacerbating the deterioration of water stability.

[0008] In summary, the existing technology cannot overcome such technical barriers of curing sea mud, and it is urgent to develop a special stabilizer with a synergistic mechanism to promote the resource utilization of sea mud. SUMMARY

[0009] To overcome the above-mentioned shortcomings, one of the purposes of the present application is to provide a special stabilizer for high-salinity and high-organic sea mud, which is especially suitable for scenarios such as reclamation, port construction, sea mud treatment and recycling of road materials, and can cure and modify high-salinity and high-organic sea mud to improve its water stability. The present application solves the technical bottleneck of poor water stability of sea mud curing body in high-salinity and high-organic environment through the synergistic effect of composite functional components.

[0010] In order to achieve the above purposes, the technical scheme adopted by the present application is: a sea mud stabilizer, the raw materials include, by weight: 5-32 parts of fluorine-modified biochar, 10-70 parts of polyvinyl acetate (VINNEX® 8803), 1-13 parts of boric acid, 0.5-8 parts of silane coupling agent, 0.5-5 parts of organosilicon-polyether block copolymer (BYK-333), 50-300 parts of solvent.

[0011] The sea mud stabilizer of the present application has excellent effect, and the possible analysis of the role of each component is as follows:

[0012] The fluorine-modified activated carbon can increase the negative charge density, so that it can maintain dispersion stability in a high-salinity environment, and then better adsorb organic matter and improve the hydrophobicity of sludge particles, block and block the migration of harmful ions such as Cl - , SO4² - ;

[0013] Polyvinyl acetate as the main bonding component can bridge sea mud particles, fluorine-modified biochar and other components through molecular chain winding to construct a flexible bonding skeleton, and the ester group structure is stable in a high-salinity environment, which can prevent salt corrosion and water erosion to a certain extent and prevent sea mud from being re-muddy;

[0014] Boric acid as a crosslinking agent ionizes to form active groups in the weak alkaline environment of sea mud, forms a reversible borate ester bond with the hydroxyl group of the polyvinyl acetate molecular chain, helps to construct a dense crosslinking network, and improves the dynamic crosslinking degree of the crosslinking network. In addition, the combination of boric acid can uniformly anchor the fluorine-modified biochar in the crosslinking network to synergistically enhance the performance of the product;

[0015] Silane coupling agent forms silicon hydroxyl groups after hydrolysis, and forms covalent bonds with the surface hydroxyl groups of sea mud minerals and biochar;

[0016] The hydrophobic end of the silicone-polyether block copolymer can adsorb the C-F bond on the surface of the fluorine-modified biochar, and the hydrophilic end faces the medium, forming micelles to avoid the agglomeration of the fluorine-modified biochar.

[0017] The above components synergistically reduce the content of organic matter and salt ions in the sludge, and improve the mechanical properties and water stability of the sludge.

[0018] Exemplarily, the fluorine-modified biochar is in a range of 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 32 parts, or any two thereof; the polyvinyl acetate is in a range of 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, or any two thereof; the boric acid is in a range of 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, or any two thereof; the silane coupling agent is in a range of 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, or any two thereof; the silicone-polyether block copolymer is in a range of 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, or any two thereof; and the solvent is in a range of 50 parts, 100 parts, 250 parts, 300 parts, or any two thereof.

[0019] Further, the raw materials include, by weight parts, 7-28 parts of fluorine-modified biochar, 16-65 parts of polyvinyl acetate, 2-7 parts of boric acid, 1-5 parts of silane coupling agent, 0.9-3.5 parts of silicone-polyether block copolymer, and 70-290 parts of solvent.

[0020] Further, the boric acid accounts for 0.4-5.1% of the total mass of the stabilizer.

[0021] Still further, the boric acid accounts for 1.5-2.5% of the total mass of the stabilizer.

[0022] Further, the mass ratio of the boric acid to the polyvinyl acetate is 1: (3-34).

[0023] Still further, the mass ratio of the boric acid to the polyvinyl acetate is 1: (8-10).

[0024] The inventors have found that the above ratios help to obtain products with better performance, and the reason may be that:

[0025] When the amount of boric acid is too small, the reversible borate ester bond formed between the boric acid and the polyvinyl acetate may be less, and the uniform anchoring of the fluorine-modified biochar is reduced, which is not conducive to improving the compactness of the cross-linked network in the system, and the porosity of the product is increased. On the one hand, insufficient cross-linking makes the molecular chain have a large activity space, and the stress is released by slipping, but the network has poor carrying capacity and is easy to deform plastically, which may cause engineering problems and cause the desorption of organic matter to compete for the bonding sites, resulting in gas production and further weakening the structure, leading to a decrease in strength. On the other hand, the high porosity makes water easily penetrate, destroy the van der Waals force, and the network disintegrates, resulting in secondary mudification, desorption of organic matter, reduction of water stability coefficient, high internal salt concentration due to salt ion penetration, accelerated degradation, and increased conductivity. After long-term soaking, hydrolysis occurs.

[0026] When the amount of boric acid is too large, the density of cross-linking nodes in the system may be too high, the network may be rigid and lose flexibility. In a high-salt and high-organic matter sea mud environment, the crack resistance is poor, the stress cannot be released, stress concentration occurs, and cracks are generated. The cracks become water penetration channels, water causes the cross-linking nodes to hydrolyze, the cracks expand, the network disintegrates, and the water stability coefficient decreases. After soaking, the cracks expand and the edges disintegrate. The mechanical properties are dry strong and wet weak, and the strength decreases when water is encountered. Salt ions penetrate along the cracks, undergo displacement reactions, and accelerate disintegration. The salt resistance fails, salt corrosion is severe at the cracks, and the structure is damaged. The construction adaptability is poor, a rigid structure is formed early, local stress concentration occurs, micro-cracks are generated, and the cracks expand later.

[0027] Illustratively, the mass ratio of boric acid to polyvinyl acetate is 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, 1:21, 1:22, 1:23, 1:24, 1:25, 1:26, 1:27, 1:28, 1:29, 1:30, 1:31, 1:32, 1:33, 1:34, or a range consisting of any two of them.

[0028] Further, the silane coupling agent is an amino silane coupling agent.

[0029] The amino group in the silane coupling agent can form a hydrogen bond with the polyvinyl acetate and adsorb free salt ions, achieving organic-inorganic interface bridging and salt ion control.

[0030] Further, the silane coupling agent is selected from at least one of 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-aminopropyltrimethoxysilane, and 3-ureidopropyltriethoxysilane.

[0031] Further, the solvent is selected from at least one of an alcohol solution and water.

[0032] Still further, the solvent is an alcohol solution.

[0033] Further, the solvent is a mixture of anhydrous ethanol and propylene glycol, and the volume ratio of the two is 1:0.5-1.5.

[0034] Further, the raw material for preparing the fluorine-modified biochar comprises biochar and hydrofluoric acid.

[0035] Further, the preparation step of the fluorine-modified biochar comprises:

[0036] S1, adding a hydrofluoric acid solution to the biochar, stirring for 2-3 h to obtain a mixture;

[0037] S2, adding 5-10 wt% calcium carbonate to the mixture in step S1 to obtain a pH value of 6.5-7.5, and post-treating to obtain the fluorine-modified biochar.

[0038] Further, in step S1, the concentration of the hydrofluoric acid solution is 5-10 wt%, and the solid-liquid ratio of the biochar and the hydrofluoric acid is 1:1-2 (g / mL).

[0039] Further, in step S2, the post-treatment comprises: standing for 20-30 min, filtering, repeatedly washing the filter residue with deionized water until no fluorine ion is detected in the filtrate, then washing with 3-5 wt% dilute hydrochloric acid, and washing with deionized water until neutral, drying at 70-90℃, grinding and sieving (80-100 mesh) to obtain the fluorine-modified biochar.

[0040] Further, the drying method in step S2 can be 70-90℃ air drying.

[0041] Further, the biochar can be directly prepared by using commercially available activated carbon, or directly prepared by using straw and / or sawdust.

[0042] Further, the method for directly preparing the biochar by using straw and / or sawdust comprises: placing the straw and / or sawdust into a tube furnace, purging oxygen with nitrogen, heating, holding, and cooling to obtain the original biochar.

[0043] Further, the method for directly preparing the biochar by using straw and / or sawdust further comprises pretreating the straw and / or sawdust, and the pretreatment comprises crushing, sieving, cleaning and drying the straw and / or sawdust, and then placing the straw and / or sawdust into the tube furnace; after purging oxygen with nitrogen, heating to 500-700℃, holding for 2-3 h, and naturally cooling to room temperature.

[0044] Further, the sea mud stabilizer is applied to the solidification modification of the sea mud, and the mass ratio of the sea mud stabilizer to the sea mud is 1-4:10000.

[0045] Another object of the present application is to provide a preparation method of the sea mud stabilizer, comprising the following steps:

[0046] Step one, add boric acid to the solvent, stir until dissolved, to obtain solution A;

[0047] Step two, drop silane coupling agent into solution A, stir to obtain solution B;

[0048] Step three, add polyvinyl acetate to solution B, stir to obtain solution C;

[0049] Step four, add silicone-polyether to solution C, stir until uniform, then add fluorine-modified biochar, mix until uniform to obtain solution D;

[0050] Step five, warm solution D, keep warm, and then reduce to room temperature to adjust the viscosity of the system, to prepare the sea mud stabilizer.

[0051] Further, in step two, the stirring time is 20-40 min.

[0052] Further, in step four, the stirring time is 10-30 min;

[0053] Further, in step five, solution D is warmed to 40-45℃, and then stirred for 0.5-1.5 h, and then naturally reduced to room temperature, and the viscosity of the system is adjusted to 500-1000 mPa s.

[0054] Further, the specific steps for adjusting the viscosity of the system are as follows: if the viscosity is >1000 mPa s, add an appropriate amount of mixed solvent of ethanol and propylene glycol in a volume ratio of 1:1, and stir at low speed for 3-5 min until the viscosity meets the standard; if the viscosity is <500 mPa s, concentrate the system at room temperature for 3-10 min until the viscosity meets the standard.

[0055] The beneficial effects of the present application are:

[0056] 1) The present application uses fluorine-modified biochar, polyvinyl acetate, boric acid, silane coupling agent, silicone-polyether block copolymer, and solvent to prepare a liquid sea mud stabilizer, which can reduce the salt ion concentration and organic matter content of sea mud, and improve its mechanical properties and water stability.

[0057] 2) The fluorine-modified biochar and polyvinyl acetate are used to construct a waterproof barrier. The polyvinyl acetate forms a water-repellent film to block the penetration of salt, and the polyvinyl acetate wraps the particles to form closed agglomerates, avoiding the contact of salt with the cementing core, to solve the problem of water stability degradation.

[0058] 3) The present application aims at the problem of organic matter wrapping, and a penetrating-crosslinking system is constructed by using boric acid and silane coupling agent: the hydroxyl group of boric acid forms hydrogen bond with humus to break the wrapping layer; the silane coupling agent realizes firm combination of the organic phase and the sea mud mineral. The solidified body is soaked without swelling and cracking in the sea mud with high organic matter content.

[0059] 4) The present application dynamically adjusts the balance between hydrophilicity and hydrophobicity by using the organic silicon-polyether block copolymer, and improves the compatibility of the organic-inorganic interface by using the silane coupling agent, so as to improve the compatibility of the stabilizer and the sea mud system, and better improve the performance of the sea mud. DETAILED DESCRIPTION

[0060] In order to make the above-mentioned objects, features and advantages of the present application more apparent and easy to understand, the specific embodiments of the present application are described in detail below. In the following description, a large number of specific details are set forth in order to facilitate a full understanding of the present application. However, the present application can be implemented in many different ways other than those described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0061] Except as shown in the operation examples or otherwise indicated, all numbers expressing quantities of ingredients, properties such as physical properties, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings of the present application. At the very least, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Numerical ranges include all numerical values and ranges between the numbers "from" and "to" and are inclusive of all numbers within that range. Ranges of numerical values include all numerical values and ranges between the numerical values end-point values, e.g., ranges from 1 to 5 include 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0062] The present application provides a sea mud stabilizer, the raw materials including 5-32 parts of fluorine modified biochar, 10-70 parts of polyvinyl acetate, 1-13 parts of boric acid, 0.5-8 parts of silane coupling agent, 0.5-5 parts of organic silicon-polyether block copolymer (BYK-333), and 50-300 parts of solvent.

[0063] In some embodiments, the raw materials of the sea mud stabilizer include 7-28 parts of fluorine modified biochar, 16-65 parts of polyvinyl acetate, 2-7 parts of boric acid, 1-5 parts of silane coupling agent, 0.9-3.5 parts of organic silicon-polyether block copolymer, and 70-290 parts of solvent.

[0064] In some embodiments, the solvent is selected from at least one of an alcohol solution or water.

[0065] In some embodiments, the solvent is an alcohol solution.

[0066] In some embodiments, the solvent is a mixture of anhydrous ethanol and propylene glycol.

[0067] In some embodiments, the volume ratio of anhydrous ethanol to propylene glycol is 1:0.5-1.5.

[0068] In some embodiments, the borate acid accounts for 0.4-5.1% of the total mass of the stabilizer.

[0069] In some embodiments, the borate acid accounts for 1.5-2.5% of the total mass of the stabilizer.

[0070] In some embodiments, the silane coupling agent is selected from at least one of 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-aminopropyltrimethoxysilane, and 3-ureidopropyltriethoxysilane.

[0071] In some embodiments, the mass ratio of the stabilizer to the sea mud is 1-4:10000.

[0072] In some embodiments, the preparation steps of the fluorine-modified biochar are as follows: weighing the biochar, adding 5-10wt% hydrofluoric acid solution, the solid-liquid ratio of biochar to hydrofluoric acid being 1:1-2 (g / mL), stirring at room temperature for 2-3h to obtain a mixed solution; adding 5-10wt% calcium carbonate to the mixed solution until the pH value of the mixed solution is 6.5-7.5, filtering after standing for 20-30min; repeatedly washing the filter residue with deionized water until no fluoride ions are detected in the filtrate, then washing with dilute hydrochloric acid and deionized water until neutral; drying at 70-90℃, grinding and sieving (80-100 mesh) to obtain the fluorine-modified biochar.

[0073] In some embodiments, the preparation steps of the sea mud stabilizer include: adding borate acid to a solvent at 25-35℃, stirring until dissolved to obtain solution A; adding a silane coupling agent to solution A, stirring for 20-40min to obtain solution B; adding polyvinyl acetate to solution B, stirring at a speed of 1300-1700rpm for 10-30min to obtain solution C; adding silicone-polyether to solution C, stirring until uniform, then adding fluorine-modified biochar, mixing until uniform to obtain solution D; heating solution D to 40-45℃, stirring for 1h, then naturally reducing to room temperature, adjusting the viscosity of the system to 500-1000mPa s, i.e. the target stabilizer.

[0074] In some embodiments, the specific steps of adjusting the viscosity of the system are as follows: if the viscosity is >1000 mPa s, adding an appropriate amount of a mixed solvent of anhydrous ethanol and propylene glycol in a volume ratio of 1:1, stirring at low speed for 3-5min until the viscosity meets the standard; if the viscosity is <500 mPa s, and the system is concentrated at room temperature for 3-10 min until the viscosity is up to standard.

[0075] Embodiment

[0076] The present disclosure is described in more detail by the following examples, which are merely illustrative and not limiting, as various modifications and changes can be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported herein are based on weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used as received without further purification, and the instruments used in the examples are commercially available.

[0077] Example 1

[0078] The preparation steps of the sea mud stabilizer include:

[0079] Step one, under room temperature, 4.5 parts of boric acid is added to 181.5 parts of solvent (volume ratio of 1:1 of absolute ethanol and propylene glycol), stirred until dissolved, to obtain solution A;

[0080] Step two, 2.7 parts of silane coupling agent 3-aminopropyl triethoxysilane is added to solution A, stirred for 30 min, to obtain solution B;

[0081] Step three, 40 parts of polyvinyl acetate is added to solution B, stirred at 1500 rpm for 20 min, to obtain solution C;

[0082] Step four, 2.2 parts of silicone-polyether block copolymer (BYK-333) is added to solution C, after stirring evenly, 17 parts of fluorine modified biochar is added, mixed evenly, to obtain solution D;

[0083] Step five, solution D is heated to 45℃, after 1h of incubation and stirring, it is naturally cooled to room temperature, the viscosity of the system is adjusted to 800 mPa s, to obtain the sea mud stabilizer.

[0084] According to the calculation, the proportion of boric acid is: 4.5 / (181.5+4.5+2.7+40+17+2.2)*100%=1.82%;

[0085] The mass ratio of boric acid and polyvinyl acetate is 4.5:40=1:8.9.

[0086] The preparation steps of the above fluorine modified biochar include:

[0087] S1, the biochar is placed in an 8wt% hydrofluoric acid solution, the solid-liquid ratio of the two is 1:1.5 (g / mL), stirred for 2.5h, to obtain a mixture;

[0088] S2, adjust the pH value of the mixture in S1 step to 7 with 8wt% calcium carbonate solution, stand for 25min, filter, stand for 20-30min before filtering; repeatedly wash the filter residue with deionized water until no fluoride ion is detected in the filtrate, then wash with 4wt% dilute hydrochloric acid, wash with deionized water until neutral, then dry at 80℃ for 3h, grind and sieve (100 mesh) to obtain fluorine modified biochar.

[0089] Example 2

[0090] Example 2 and the preparation process of Example 1 are basically the same, the main difference is that the preparation of raw materials is different, specifically: fluorine modified biochar 7 parts; polyvinyl acetate 16 parts; boric acid 2 parts; silane coupling agent 3-aminopropyl triethoxysilane 1.1 parts; silicone-polyether block copolymer 0.9 parts; solvent 73.2 parts.

[0091] The proportion of boric acid is calculated as: 2 / (7+16+2+1.1+0.9+73.2)*100%=2.0%;

[0092] The mass ratio of boric acid and polyvinyl acetate is 2:16=1:8.

[0093] Example 3

[0094] Example 3 and the preparation process of Example 1 are basically the same, the main difference is that the preparation of raw materials is different, specifically: fluorine modified biochar 28 parts; polyvinyl acetate 64.5 parts; boric acid 6.5 parts; silane coupling agent 3-aminopropyl triethoxysilane 4.5 parts; silicone-polyether block copolymer 3.5 parts; solvent 290 parts.

[0095] The proportion of boric acid is calculated as: 6.5 / (28+64.5+6.5+4.5+3.5+290)*100%=1.64%;

[0096] The mass ratio of boric acid and polyvinyl acetate is 6.5:64.5=1:9.9.

[0097] Example 4

[0098] Example 4 and the preparation process of Example 1 are basically the same, the main difference is that the preparation of raw materials is different, specifically: fluorine modified biochar 15.5 parts; polyvinyl acetate 38.5 parts; boric acid 12.5 parts; silane coupling agent 3-aminopropyl triethoxysilane 1.1 parts; silicone-polyether block copolymer 0.6 parts; solvent 179.7 parts.

[0099] The proportion of boric acid is calculated as: 12.5 / (15.5+38.5+12.5+1.1+0.6+179.7)*100%=5.04%;

[0100] The mass ratio of boric acid to polyvinyl acetate is 12.5:38.5 = 1:3.1.

[0101] Example 5

[0102] The preparation processes of Example 5 and Example 1 are basically the same, the main difference being the different proportions of the raw materials, specifically: 17.7 parts of fluorinated biochar; 40.7 parts of polyvinyl acetate; 1.2 parts of boric acid; 3.4 parts of silane coupling agent 3-aminopropyltriethoxysilane; 2.8 parts of organosilicon-polyether block copolymer; and 182.1 parts of solvent.

[0103] The calculated percentage of boric acid is: 1.2 / (17.7 + 40.7 + 1.2 + 3.4 + 2.8 + 182.1) * 100% = 0.48%;

[0104] The mass ratio of boric acid to polyvinyl acetate is 1.2:40.7 = 1:33.9.

[0105] Comparative Example 1

[0106] The preparation processes of Comparative Example 1 and Example 1 are basically the same, the main difference being that activated carbon (unmodified) is used instead of fluorine-modified biochar in Example 1.

[0107] Comparative Example 2

[0108] The preparation processes of Comparative Example 2 and Example 1 are basically the same, the main difference being that zinc borate is used instead of boric acid in Example 1.

[0109] Comparative Example 3

[0110] The preparation processes of Comparative Example 3 and Example 1 are basically the same, the main difference being that boric acid was not added. Specifically, the components are: 18.2 parts of fluorinated biochar; 41.7 parts of polyvinyl acetate (PVAc); 0 parts of boric acid; 3.5 parts of silane coupling agent 3-aminopropyltriethoxysilane; 3 parts of organosilicon-polyether block copolymer; and 181.5 parts of solvent.

[0111] Comparative Example 4

[0112] The preparation processes of Comparative Example 4 and Example 1 are basically the same, the main difference being that the component organosilicon-polyether block copolymer was not added, specifically: 17.6 parts of fluorinated biochar; 40.9 parts of polyvinyl acetate (PVAc); 4.9 parts of boric acid; 3 parts of silane coupling agent 3-aminopropyltriethoxysilane; 0 parts of organosilicon-polyether block copolymer; and 181.5 parts of solvent.

[0113] Experimental Examples

[0114] Silt samples taken from dredging projects along the coast of Fujian Province had the following initial properties after air drying: a salt content (EC) of not less than 8 mS / cm, an organic matter content of 15.6%, and a fishy odor. Using stabilizers prepared in Examples 1-5 and Comparative Examples 1-4, silt, cement, and stabilizer were mixed in a mass ratio of 100:6:0.0002. The mixture was then used to prepare test blocks with a moisture content of 14.6% according to industry standard JTG E51-2009. The test blocks were numbered, bagged to remove air, and cured for 7 days in a standard curing chamber at 25±2℃ and 95% humidity. The 7-day unconfined compressive strength, water stability, electrical conductivity, and organic matter content of the test blocks were tested. Specific test data are shown in Table 1. The specific test methods are as follows:

[0115] Unconfined compressive strength: Refer to the "Test Procedure for Inorganic Binder Stabilized Materials in Highway Engineering" (TG 3441-2024) to test the 7-day unconfined compressive strength of the specimens.

[0116] Water stability test: The water stability of the specimens was tested in accordance with the "Technical Standard for Application of Soil Stabilizers" (CJJ / T 286-2018).

[0117] Electrical conductivity: The extraction was carried out in accordance with the "Analysis of Water-Soluble Salts in Forest Soils" (LY / T 1251—1999), and the total salt content in the leachate was determined by electrical conductivity method.

[0118] Organic matter content: Referring to the "Determination of Organic Matter in Solid Waste by Loss on Ignition Method" (HJ 761-2015), a certain mass of the cured sample was weighed and the organic matter content in the sample was determined using a muffle furnace.

[0119] Table 1

[0120]

[0121] As shown in Table 1, the test blocks prepared using the technical solution of this application in Examples 1-3 have good performance in all aspects. Among them, the 7-day unconfined compressive strength is above 2.6 MPa, the water stability is above 88%, the conductivity is below 3.8 mS / cm, and the organic content in the test blocks is below 7.7%.

[0122] Compared with Example 1, all other properties in Example 4 decreased. The possible reasons are as follows: the ratio of boric acid to polyvinyl acetate was 1:3.1, and the excessive use of boric acid led to dense cross-linking nodes, excessive cross-linking of the system, high network rigidity and poor flexibility, resulting in an inability to effectively disperse external stress, thus reducing strength. At the same time, the content of fluorine-modified biochar in the system decreased, which also reduced the adsorption effect on organic matter, thus increasing the organic matter content in the sample. In addition, the test results showed that the water stability and salt ion fixation capacity of the sample also decreased.

[0123] Compared to Example 1, all properties in Example 5 decreased. The possible reasons are as follows: the ratio of boric acid to polyvinyl acetate was 1:33.9, and the amount of boric acid was insufficient. This may have resulted in fewer reversible borate bonds formed between boric acid and polyvinyl acetate, reducing the crosslinking density and dynamic crosslinking degree of the system. On the one hand, this reduced the sample's ability to disperse external stress, leading to a decrease in strength. On the other hand, it increased the porosity of the sample, making it easier for water to penetrate, thus affecting water stability and salt ion fixation ability. In addition, the reduction in the amount of boric acid also reduced the uniform anchoring of the modified biochar in the crosslinking network, affecting the full adsorption of organic matter, thus increasing the organic matter content of the sample.

[0124] Compared to Example 1, the performance of Comparative Example 1 decreased. The possible reason is that the added activated carbon was not fluorinated, leading to hydrophobic failure and a decrease in the sample's water stability and salt ion immobilization capacity. The data also show a decrease in the sample's compressive strength and organic matter adsorption capacity.

[0125] Compared with Example 1, all performance indicators in Comparative Example 2 decreased. The possible reason is that the zinc ions (Zn) in zinc borate... 2+ It will form a complex with the ester group of polyvinyl acetate, occupying more potential reaction sites and affecting the overall crosslinking effect, thus reducing the various properties of the sample.

[0126] Compared with Example 1, the performance of Comparative Example 3 decreased significantly. The possible reason is that boric acid was not added to the system, so it could not form reversible borate bonds with polyvinyl acetate, resulting in a loose cross-linking structure. This also affected the uniformity of the distribution of fluorinated biochar in the cross-linking network, thus causing a significant decrease in the performance of the sample.

[0127] Compared with Example 1, all properties of Comparative Example 4 decreased. The possible reason is that the system did not contain organosilicon-polyether block copolymer, which may have affected the dispersibility of fluorinated biochar in the system, thus causing a decrease in the properties of the sample.

[0128] This invention illustrates the detailed process equipment and process flow through the above embodiments. However, this invention is not limited to the detailed process equipment and process flow described above, meaning that this invention does not necessarily depend on the detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, structural changes, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

[0129] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0130] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0131] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

[0132] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A marine mud stabilizer characterized by, The raw materials include, by weight parts: 5-32 parts of fluorine modified biochar, 10-70 parts of polyvinyl acetate, 1-13 parts of boric acid, 0.5-8 parts of silane coupling agent, 0.5-5 parts of silicone-polyether block copolymer, 50-300 parts of solvent; The preparation raw materials of the fluorine modified biochar include biochar and hydrofluoric acid; The preparation steps of the fluorine modified biochar are: S1, adding hydrofluoric acid solution to the biochar, stirring for 2-3h, and obtaining a mixed solution; S2, adding 5-10wt% calcium carbonate solution to adjust the pH value of the mixed solution to 6.5-7.5, and obtaining the fluorine modified biochar after post-treatment; In the step S1, the concentration of the hydrofluoric acid solution is 5-10wt%, and the solid-liquid ratio of the biochar to the hydrofluoric acid is 1:1-2(g / mL); In the step S2, the post-treatment includes: filtering after standing, washing the filter residue with deionized water until no fluoride ion is detected in the filtrate, then washing with dilute hydrochloric acid, and washing with deionized water until neutral, drying, grinding and sieving to obtain the fluorine modified biochar; Including at least one of the following technical features: The boric acid accounts for 0.4-5.1% of the total mass of the stabilizer; The mass ratio of the boric acid to the polyvinyl acetate is 1:(8-10); The silane coupling agent is an amino silane coupling agent; The solvent is selected from at least one of alcohol solution and water.

2. The marine mud stabilizer of claim 1, wherein, The raw materials include, by weight parts: 7-28 parts of fluorine modified biochar, 16-65 parts of polyvinyl acetate, 2-7 parts of boric acid, 1-5 parts of silane coupling agent, 0.9-3.5 parts of silicone-polyether block copolymer, and 70-290 parts of solvent.

3. The sea mud stabilizer according to claim 1, characterized in that, The silane coupling agent is selected from at least one of 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-aminopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane; The solvent is a mixture of anhydrous ethanol and propylene glycol, and the volume ratio of anhydrous ethanol to propylene glycol is 1:0.5-1.5; The boric acid accounts for 1.5-2.5% of the total mass of the stabilizer.

4. The marine mud stabilizer of claim 1, wherein, It is applied to the solidification modification of sea mud, and the mass ratio of the sea mud stabilizer to the sea mud is 1-4:10000.

5. The method of preparing a marine mud stabilizer according to any one of claims 1-4, wherein, Including the following steps: Step one, adding boric acid to the solvent and stirring until dissolved to obtain solution A; Step two, adding silane coupling agent to solution A and stirring to obtain solution B; Step three, adding polyvinyl acetate to solution B and stirring to obtain solution C; Step four, adding silicone-polyether to solution C, stirring uniformly, then adding fluorine modified biochar, mixing uniformly, and obtaining solution D; Step five, adjusting the viscosity of the system by heating, holding and cooling to room temperature to prepare the sea mud stabilizer.

6. The preparation method of the sea mud stabilizer according to claim 5, characterized in that, In the step two, the stirring time is 20-40min; In the step three, the stirring time is 10-30min; In step five, solution D is warmed to 40-45°C, and after 0.5-1.5 h of incubation with stirring, it is allowed to cool to room temperature, and the viscosity of the system is adjusted to 500-1000 mPa s.

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