High-strength impermeable inorganic plugging agent and preparation method thereof

Abstract

The application belongs to the technical field of waterproof plugging materials, and particularly relates to a high-strength anti-permeation inorganic plugging agent and a preparation method thereof. The inorganic plugging agent comprises the following raw materials in parts by weight: 60-70 parts of sulphoaluminate cement; 10-15 parts of gypsum; 5-8 parts of quicklime; 3-6 parts of an admixture; and 0.2-0.3 parts of a water reducing agent. The preparation method of the inorganic plugging agent is simple, the setting and curing time is short, the strength is high, the adhesive force is strong, the waterproof and anti-permeation properties and the durability are good, and the components can be crosslinked and set with each other during use, so that a good long-term plugging effect is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of waterproof plugging materials, and particularly relates to a high-strength anti-permeation inorganic plugging agent and a preparation method thereof. BACKGROUND

[0002] Leakage of hydraulic concrete structures is one of the most common diseases among various damage phenomena of hydraulic structures, and can be divided into several types according to different positions, such as leakage of the structure itself, leakage of the foundation, leakage of the contact surface between the bottom plate and the foundation, and side leakage. Waterproof plugging materials are usually used for water plugging, and existing waterproof plugging materials are mainly divided into organic plugging agents and inorganic plugging agents. The main component of the organic plugging agent is a high molecular polymer, which is prone to aging for a long time, resulting in poor effect when used for waterproof plugging of concrete structures. The inorganic plugging agent does not have the problem of aging, has the advantages of rapid solidification on the surface of the concrete structure, low production cost, good plugging effect, and is most widely used for waterproof plugging of buildings.

[0003] A patent with the application number 201710702896.1 discloses a waterproof plugging material and a preparation method thereof. The waterproof plugging material comprises the following components: 300-600 parts of sulphoaluminate cement, 200-400 parts of high aluminate cement, 100-200 parts of heavy calcium carbonate, 100-200 parts of washed river sand, 0.2-1 part of a quick-setting agent, 0.2-0.5 part of a water-retaining agent, 0.5-2 parts of a water-reducing agent, 3-6 parts of a re-dispersible glue powder, 0.3-0.5 part of a defoaming agent, 1-3 parts of a powder leveling agent, and 0.1-0.2 part of polypropylene fiber. Although the plugging material has good waterproof and anti-permeation properties, it needs to use a coagulant and a hardening agent to achieve the ideal plugging effect of the system. However, the use of the coagulant and the hardening agent affects the late strength and waterproof performance of the material to some extent, and the long-acting property of the plugging is insufficient, which cannot meet the requirements of surface water plugging in areas such as the floor and wall of the indoor washroom and kitchen. A patent with the application number 202210135905.4 discloses a waterproof enhanced inorganic plugging material and a preparation method thereof. The waterproof enhanced inorganic plugging material is prepared by using 720-850 parts of cement, 3-10 parts of a water-reducing agent, 2-8 parts of a cellulose ether, 5-15 parts of a permeation and crystallization active masterbatch, 4-10 parts of quicklime, 3-7 parts of microsilica powder, 120-200 parts of quartz sand, and 3-8 parts of a functional additive. The waterproof enhanced inorganic plugging material has the advantages of fast coagulation and hardening, high initial strength and late strength, good waterproof and anti-permeation performance, and good durability. The prepared inorganic plugging material is particularly suitable for surface water plugging in areas such as the floor and wall of the indoor washroom and kitchen. However, the strength of the inorganic plugging material still needs to be improved. Therefore, it is urgent to develop an inorganic plugging agent with high strength and good plugging effect to meet the market demand. SUMMARY

[0004] The present application aims at solving the problems of the prior art, and provides a high-strength anti-permeation inorganic plugging agent and a preparation method thereof.

[0005] The technical scheme adopted by the present application to achieve the above-mentioned purpose is as follows:

[0006] The high-strength anti-permeation inorganic plugging agent comprises the following raw materials in parts by weight: 60-70 parts of sulphoaluminate cement, 10-15 parts of gypsum, 5-8 parts of quicklime, 3-6 parts of additive, and 0.2-0.3 parts of water reducing agent.

[0007] Further, the additive is prepared by adding acrylamide, modified nano calcium carbonate, polyhydroxymethyl biphenyl and dispersant into deionized water, stirring uniformly, heating to 80-90 DEG C under nitrogen protection, dropping 20-30% ammonium persulfate aqueous solution, reacting for 4-6 hours, filtering after cooling, and crushing the filter residue after drying to obtain the additive; the dispersant is one or a mixture of several of sodium dodecyl sulfate, sodium lauryl polyoxyethylene ether sulfate and sodium cetyl polyoxyethylene ether phosphate; the mass ratio of acrylamide, modified nano calcium carbonate, polyhydroxymethyl biphenyl, dispersant and ammonium persulfate is 1:0.2-0.4:0.1-0.2:0.05-0.1:0.02-0.05; and the crushing is to 300-400 mesh.

[0008] Further, the preparation method of the modified nano calcium carbonate is as follows:

[0009] S1, adding chloromethyl vinyl benzene into N,N-dimethyl formamide, dropping concentrated sulfuric acid under nitrogen protection, heating to 70-80 DEG C, and reacting for 2-4 hours to obtain p-chloromethyl vinyl benzene sulfonic acid with the chemical structural formula of:

[0010] The molar ratio of chloromethyl vinyl benzene and concentrated sulfuric acid is 1:1.5-2;

[0011] S2, dispersing nano calcium carbonate in ethanol, adding p-chloromethyl vinyl benzene sulfonic acid, heating to 60-70 DEG C, and reacting for 4-6 hours, filtering after cooling, and drying the filter residue to obtain modified nano calcium carbonate; the mass ratio of nano calcium carbonate and p-chloromethyl vinyl benzene sulfonic acid is 1:0.1-0.2; and the concentration of nano calcium carbonate is 0.2-0.3 g / mL.

[0012] Further, the preparation method of the polyhydroxymethyl biphenyl is: 4,4'-dihydroxy biphenyl, 37% formaldehyde solution is uniformly mixed, sodium hydroxide is added, the temperature is increased to 40-50 DEG C, and the reaction is carried out for 10-12 h, after cooling, glacial acetic acid, acetone is added in turn, stirring is carried out for 20-30 min, filtration is carried out, and the filtrate is concentrated under reduced pressure to obtain polyhydroxymethyl biphenyl, and the chemical structural formula is:

[0013] The molar ratio of 4,4'-dihydroxy biphenyl, formaldehyde and sodium hydroxide is 1:4-4.5:2-2.5; the molar amount of glacial acetic acid is the same as that of sodium hydroxide; and the mass ratio of glacial acetic acid to acetone is 1:5-10.

[0014] The application provides a preparation method of high-strength anti-permeation inorganic plugging agent, and comprises the following steps: according to weight proportion, sulfate cement, gypsum, quicklime, additive and water reducing agent are sequentially added into a stirring machine, and are uniformly stirred and mixed to obtain the inorganic plugging agent; the stirring speed is 600-800 r / min; and the stirring time is 20-30 min.

[0015] The application has the following beneficial effects:

[0016] The application grafts p-chloromethyl vinyl benzene sulfonic acid to the surface of nano calcium carbonate through chemical reaction to obtain modified nano calcium carbonate, which contains rigid benzene ring groups, p-chloromethyl vinyl benzene sulfonic acid groups and inorganic rigid nano calcium carbonate in the structure, can improve the strength of the gel on one hand, and can also participate in the polymerization of acrylamide monomers on the other hand, so that the inorganic material nano calcium carbonate is fully and uniformly introduced into the gel to form an organic and inorganic cross-linked three-dimensional network high-strength polymer gel additive; in addition, the rigid benzene ring groups in the structure of the polyhydroxymethyl biphenyl can better support the spatial structure of the formed gel, and the plurality of polar groups can also further cross-link with the amide groups in the three-dimensional network molecular chains of the gel, so that the three-dimensional network molecular structure of the gel is better, and the high-strength polymer gel additive can be better cross-linked and solidified with other components of the inorganic plugging agent to improve the bonding strength of the plugging agent; the prepared high-strength polymer gel additive is added into the inorganic plugging agent, can also fill the micro-pores formed by other gel materials, improve the compactness and density of the plugging agent, and further improve the comprehensive performance of the plugging agent.

[0017] The application provides the high-strength anti-permeation inorganic plugging agent with short setting and solidification time, high strength, strong bonding force, good waterproof and anti-permeability and durability, and the preparation method of the inorganic plugging agent is simple; in the use process, the components can be cross-linked and set with each other to achieve good long-term plugging effect. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0019] Acrylamide CAS No. 79-06-1; nano calcium carbonate CAS No. 471-34-1; ammonium persulfate CAS No. 7727-54-0; sodium dodecyl sulfate CAS No. 151-21-3; sodium laureth sulfate CAS No. 68585-34-2; chloromethyl vinyl benzene CAS No. 30030-25-2; concentrated sulfuric acid CAS No. 7664-93-9; 4,4'-dihydroxydiphenyl CAS No. 92-88-6; formaldehyde CAS No. 50-00-0; sodium hydroxide CAS No. 1310-73-2; potassium hydroxide CAS No. 1310-58-3; glacial acetic acid CAS No. 64-19-7; N,N-dimethylformamide CAS No. 68-12-2; dichloromethane CAS No. 75-09-2; acetone CAS No. 67-64-1; ethanol CAS No. 64-17-5; all chemical reagents are commercially available.

[0020] Embodiment 1

[0021] A high-strength anti-permeability inorganic plugging agent, comprising the following raw materials by weight: 70 parts of sulfoaluminate cement; 15 parts of gypsum; 8 parts of quicklime; 6 parts of admixture; 0.3 parts of water reducing agent; wherein the water reducing agent is a sodium polycarboxylate type water reducing agent, specifically PC-6220 (purchased from Suzhou Xingbang Chemical Building Material Co., Ltd.);

[0022] A preparation method of a high-strength anti-permeability inorganic plugging agent, comprising the following steps: according to the weight ratio, adding sulfoaluminate cement, gypsum, quicklime, admixture and water reducing agent into a stirrer in sequence, stirring and mixing uniformly to obtain the inorganic plugging agent; the stirring speed is 800 r / min; the stirring time is 30 min.

[0023] The preparation method of the admixture is as follows: acrylamide, modified nano calcium carbonate, polyhydroxymethyl diphenyl, dispersant are added into deionized water and stirred uniformly, under nitrogen protection, the temperature is raised to 90℃, 30% ammonium persulfate aqueous solution is added dropwise, the reaction is carried out for 6h, after cooling, filtration is carried out, the filter residue is dried and crushed to 400 meshes to obtain the admixture; wherein the dispersant is sodium dodecyl sulfate; the mass ratio of acrylamide, modified nano calcium carbonate, polyhydroxymethyl diphenyl, dispersant and ammonium persulfate is 1:0.4:0.2:0.1:0.05; the amount of deionized water is 3 times the total mass of acrylamide and modified nano calcium carbonate.

[0024] The preparation method of the modified nano calcium carbonate is:

[0025] S1, 30.0 g of chloromethylvinylbenzene is added to 1000 mL of N,N-dimethylformamide, 38.6 g of concentrated sulfuric acid is added dropwise under nitrogen protection, the temperature is raised to 80℃, and the reaction is carried out for 4 h. After cooling, 1000 mL of water and 2000 mL of dichloromethane are added for extraction, the organic phase is collected, and concentrated under reduced pressure to obtain 39.6 g of p-chloromethylvinylbenzene sulfonic acid; wherein the molar ratio of chloromethylvinylbenzene and concentrated sulfuric acid is 1:2; the chemical reaction process is:

[0026]

[0027] p-chloromethylvinylbenzene sulfonic acid: ESI (m / z): 233.6 [M+H] + , 1 H-NMR (600MHz, DMSO-d6, δppm): 8.51 (s, 1H), 7.83 (d, J=8.6Hz, 2H), 7.63 (d, J=8.6Hz, 2H), 6.30-6.31 (m, 1H), 5.44 (d, J=7.4Hz, 1H), 4.99-5.01 (m, 2H).

[0028] S2, the nano calcium carbonate is dispersed in ethanol, p-chloromethylvinylbenzene sulfonic acid is added, the temperature is raised to 70℃, and the reaction is carried out for 6 h. After cooling, filtration is carried out, and the filter residue is dried to obtain modified nano calcium carbonate; wherein the mass ratio of nano calcium carbonate and p-chloromethylvinylbenzene sulfonic acid is 1:0.2; the concentration of nano calcium carbonate is 0.3 g / mL.

[0029] The preparation method of the polyhydroxymethyl biphenyl is: 36.0 g of 4,4'-dihydroxybiphenyl, 70.6 g of 37% formaldehyde solution are uniformly mixed, 19.3 g of sodium hydroxide is added, the temperature is raised to 50℃, and the reaction is carried out for 12 h. After cooling, 29.0 g of glacial acetic acid and 290.0 g of acetone are added in sequence, stirred for 30 min, filtered, and the filtrate is concentrated under reduced pressure to obtain 50.5 g of polyhydroxymethyl biphenyl; wherein the molar ratio of 4,4'-dihydroxybiphenyl, formaldehyde and sodium hydroxide is 1:4.5:2.5; the molar amount of glacial acetic acid is the same as that of sodium hydroxide; the mass ratio of glacial acetic acid and acetone is 1:10; wherein 4,4'-dihydroxybiphenyl and formaldehyde are first generated into polyhydroxymethyl biphenyl sodium salt under the action of sodium hydroxide, and then the polyhydroxymethyl biphenyl sodium salt is neutralized with glacial acetic acid to generate polyhydroxymethyl biphenyl, and the chemical reaction process is:

[0030]

[0031] Polyhydroxymethyl biphenyl: ESI (m / z): 307.3 [M+H] + , 1H-NMR (600MHz, DMSO-d6, δppm): 7.37 (s, 2H), 7.03 (s, 4H), 7.63-7.65 (m, 4H), 4.61 (s, 8H).

[0032] Example 2

[0033] A high-strength anti-permeability inorganic plugging agent, comprising the following raw materials by weight: 60 parts of sulphoaluminate cement; 10 parts of gypsum; 5 parts of quicklime; 3 parts of additive; 0.2 parts of water reducing agent; wherein the water reducing agent is a polycarboxylate sodium type water reducing agent, specifically PC-6220;

[0034] A preparation method of a high-strength anti-permeability inorganic plugging agent, comprising the following steps: according to the weight ratio, sulphoaluminate cement, gypsum, quicklime, additive and water reducing agent are sequentially added into a stirrer, and stirred and mixed uniformly to obtain the inorganic plugging agent; the stirring speed is 600 r / min; the stirring time is 30 min.

[0035] The preparation method of the additive is as follows: acrylamide, modified nano calcium carbonate, polyhydroxymethyl biphenyl and dispersant are added into deionized water and stirred uniformly, under nitrogen protection, the temperature is raised to 80℃, 20% ammonium persulfate aqueous solution is added dropwise, and the reaction is carried out for 5h, then after cooling, the filter residue is dried and crushed to 300 meshes to obtain the additive; wherein the dispersant is sodium lauryl polyoxyethylene ether sulfate; the mass ratio of acrylamide, modified nano calcium carbonate, polyhydroxymethyl biphenyl, dispersant and ammonium persulfate is 1:0.2:0.1:0.05:0.02; the amount of deionized water is 3 times the total mass of acrylamide and modified nano calcium carbonate.

[0036] The preparation methods of the modified nano calcium carbonate and the polyhydroxymethyl biphenyl are the same as those in Example 1.

[0037] Example 3

[0038] A high-strength anti-permeability inorganic plugging agent, comprising the following raw materials by weight: 65 parts of sulphoaluminate cement; 10 parts of gypsum; 8 parts of quicklime; 5 parts of additive; 0.2 parts of water reducing agent; wherein the water reducing agent is a polycarboxylate sodium type water reducing agent, specifically PC-6220;

[0039] A preparation method of a high-strength anti-permeability inorganic plugging agent, comprising the following steps: according to the weight ratio, sulphoaluminate cement, gypsum, quicklime, additive and water reducing agent are sequentially added into a stirrer, and stirred and mixed uniformly to obtain the inorganic plugging agent; the stirring speed is 700 r / min; the stirring time is 30 min.

[0040] The preparation method of the additive is as follows: acrylamide, modified nano calcium carbonate, polyhydroxymethyl biphenyl, dispersant are added into deionized water, stirred uniformly, under nitrogen protection, heated to 90 DEG C, 20% ammonium persulfate aqueous solution is added dropwise, reaction for 4h, after cooling, filter, filter residue is dried and crushed to 400 mesh, to obtain the additive; wherein the dispersant is sodium lauryl polyoxyethylene ether sulfate; the mass ratio of acrylamide, modified nano calcium carbonate, polyhydroxymethyl biphenyl, dispersant, ammonium persulfate is 1:0.4:0.1:0.05:0.05; the amount of deionized water is 3 times the total mass of acrylamide and modified nano calcium carbonate.

[0041] The preparation methods of the modified nano calcium carbonate and the polyhydroxymethyl biphenyl are the same as those in Example 1.

[0042] Example 4

[0043] A high-strength anti-permeability inorganic plugging agent, comprising the following raw materials by weight: 60 parts of sulphoaluminate cement; 15 parts of gypsum; 5 parts of quicklime; 4 parts of additive; 0.3 parts of water reducing agent; wherein the water reducing agent is a polycarboxylate sodium type water reducing agent, specifically PC-6220;

[0044] A preparation method of a high-strength anti-permeability inorganic plugging agent, comprising the following steps: according to the weight ratio, sulphoaluminate cement, gypsum, quicklime, additive, water reducing agent are sequentially added into a mixer, stirred and mixed uniformly to obtain the inorganic plugging agent; the stirring speed is 800 r / min; the stirring time is 30 min.

[0045] The preparation method of the additive is the same as that in Example 1.

[0046] Comparative Example 1

[0047] A high-strength anti-permeability inorganic plugging agent, comprising the following raw materials by weight: 70 parts of sulphoaluminate cement; 15 parts of gypsum; 8 parts of quicklime; 6 parts of additive; 0.3 parts of water reducing agent; wherein the water reducing agent is a polycarboxylate sodium type water reducing agent, specifically PC-6220;

[0048] A preparation method of a high-strength anti-permeability inorganic plugging agent, comprising the following steps: according to the weight ratio, sulphoaluminate cement, gypsum, quicklime, additive, water reducing agent are sequentially added into a mixer, stirred and mixed uniformly to obtain the inorganic plugging agent; the stirring speed is 800 r / min; the stirring time is 30 min.

[0049] The preparation method of the additive is as follows: acrylamide, polyhydroxymethyl biphenyl, dispersant are added into deionized water, stirred uniformly, under nitrogen protection, heated to 90 DEG C, drop 30% ammonium persulfate aqueous solution, reaction 6h, after cooling, filter, filter residue is dried and crushed to 400 mesh, to obtain additive; wherein the dispersant is sodium dodecyl sulfate; the mass ratio of acrylamide, polyhydroxymethyl biphenyl, dispersant, ammonium persulfate is 1:0.2:0.1:0.05; the amount of deionized water is 3 times the mass of acrylamide.

[0050] The preparation method of the polyhydroxymethyl biphenyl is the same as that in embodiment 1.

[0051] Comparative example 2

[0052] A high-strength anti-permeability inorganic plugging agent, comprising the following raw materials by weight: 70 parts of sulphoaluminate cement; 15 parts of gypsum; 8 parts of quicklime; 6 parts of additive; 0.3 parts of water reducing agent; wherein the water reducing agent is a polycarboxylate sodium type water reducing agent, specifically PC-6220;

[0053] A preparation method of a high-strength anti-permeability inorganic plugging agent, comprising the following steps: according to the weight ratio, sulphoaluminate cement, gypsum, quicklime, additive, water reducing agent are sequentially added into a stirrer, stirred and mixed uniformly to obtain the inorganic plugging agent; the stirring speed is 800 r / min; the stirring time is 30 min.

[0054] The preparation method of the additive is as follows: acrylamide, modified nano calcium carbonate, dispersant are added into deionized water, stirred uniformly, under nitrogen protection, heated to 90 DEG C, drop 30% ammonium persulfate aqueous solution, reaction 6h, after cooling, filter, filter residue is dried and crushed to 400 mesh, to obtain additive; wherein the dispersant is sodium dodecyl sulfate; the mass ratio of acrylamide, modified nano calcium carbonate, dispersant, ammonium persulfate is 1:0.4:0.1:0.05; the amount of deionized water is 3 times the total mass of acrylamide and modified nano calcium carbonate.

[0055] The preparation method of the modified nano calcium carbonate is the same as that in embodiment 1.

[0056] Comparative example 3

[0057] A high-strength anti-permeability inorganic plugging agent, comprising the following raw materials by weight: 70 parts of sulphoaluminate cement; 15 parts of gypsum; 8 parts of quicklime; 0.3 parts of water reducing agent; wherein the water reducing agent is a polycarboxylate sodium type water reducing agent, specifically PC-6220;

[0058] A preparation method of a high-strength anti-permeability inorganic plugging agent, comprising the following steps: according to the weight ratio, sulphoaluminate cement, gypsum, quicklime, water reducing agent are sequentially added into a stirrer, stirred and mixed uniformly to obtain the inorganic plugging agent; the stirring speed is 800 r / min; the stirring time is 30 min.

[0059] Related tests

[0060] According to GB 23440-2009 standard, the inorganic plugging agent prepared in Examples 1-4 and Comparative Examples 1-3 was tested for setting time, compressive strength, flexural strength, impermeability, freeze-thaw cycle, heat resistance (100℃, 5h) and bonding strength, and the performance test results are shown in Table 1.

[0061] Table 1 Performance test results of inorganic plugging agent

[0062]

[0063]

[0064] As can be seen from the results in Table 1, the inorganic plugging agent prepared in Examples 1-4 has short setting and curing time, high strength, strong bonding force, good waterproof and impermeability and durability, and the comprehensive performance is much better than that of Comparative Examples 1-3; compared with Comparative Examples 1-3, the additive added in Example 1 is a high-strength polymer gel formed by acrylamide, modified nano calcium carbonate and polyhydroxymethyl biphenyl, the modified nano calcium carbonate structure contains rigid benzene ring groups and inorganic rigid nano calcium carbonate, which can improve the strength of the gel, and the p-chloromethyl vinyl benzene sulfonic acid groups of the chemically grafted nano calcium carbonate can participate in the polymerization of acrylamide monomers, so that the inorganic material nano calcium carbonate is fully and uniformly introduced into the gel, thereby forming an organic-inorganic cross-linked high-strength polymer gel additive; in addition, the rigid benzene ring groups in the structure of polyhydroxymethyl biphenyl can better support the three-dimensional network space of the formed gel, and the multiple polar groups can further cross-link with the amide groups in the three-dimensional network molecular chains of the gel, which helps to form a better gel with a three-dimensional network molecular structure, and can better cross-link and solidify with other components of the inorganic plugging agent, thereby improving the bonding strength of the plugging agent; the high-strength polymer gel additive prepared in the application can also fill the micro-pores formed by other gel materials when added to the inorganic plugging agent, thereby improving the density and compactness of the plugging agent, and thus improving the strength, bonding force, waterproof and impermeability and durability of the plugging agent.

[0065] It should be noted that in this document, terms such as "including", "containing" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or equipment; although the embodiments of the application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the application, and the scope of the application is defined by the appended claims and their equivalents.

Claims

1. A high-strength, impermeable inorganic sealant, characterized in that, The inorganic sealant comprises the following raw materials in parts by weight: 60-70 parts sulfoaluminate cement; 10-15 parts gypsum; 5-8 parts quicklime; 3-6 parts admixture; and 0.2-0.3 parts water-reducing agent. The admixture is prepared by: Acrylamide, modified nano-calcium carbonate, polyhydroxymethyl biphenyl, and dispersant were added to deionized water and stirred until homogeneous. Under nitrogen protection, the temperature was raised to 80-90℃, and 20-30% ammonium persulfate aqueous solution was added dropwise. The reaction was carried out for 4-6 hours, cooled, filtered, and the filter residue was dried and pulverized to obtain the additive. The mass ratio of acrylamide, modified nano-calcium carbonate, polyhydroxymethyl biphenyl, dispersant, and ammonium persulfate was 1:0.2-0.4:0.1-0.2:0.05-0.1:0.02-0.

05. The preparation method of the modified nano-calcium carbonate is as follows: S1. Add chloromethylvinylbenzene to N,N-dimethylformamide, add concentrated sulfuric acid dropwise under nitrogen protection, heat to 70-80℃, and react for 2-4 hours to obtain p-chloromethylvinylbenzene sulfonic acid; S2. Disperse nano-calcium carbonate in ethanol, add p-chloromethylvinylbenzenesulfonic acid, heat to 60-70℃, react for 4-6 hours, cool and filter, and dry the filter residue to obtain modified nano-calcium carbonate.

2. The high-strength impermeable inorganic sealant according to claim 1, characterized in that, The molar ratio of chloromethylvinylbenzene and concentrated sulfuric acid in step S1 is 1:1.5-2.

3. The high-strength impermeable inorganic sealant according to claim 1, characterized in that, In step S2, the mass ratio of nano-calcium carbonate to p-chloromethylvinylbenzenesulfonic acid is 1:0.1-0.2; the concentration of nano-calcium carbonate is 0.2-0.3 g / mL.

4. The high-strength impermeable inorganic sealant according to claim 1, characterized in that, The preparation method of the polyhydroxymethyl biphenyl is as follows: 4,4'-dihydroxybiphenyl and 37% formaldehyde solution are mixed evenly, sodium hydroxide is added, the temperature is raised to 40-50℃, the reaction is carried out for 10-12 hours, after cooling, glacial acetic acid and acetone are added in sequence, the mixture is stirred for 20-30 minutes, filtered, and the filtrate is concentrated under reduced pressure to obtain polyhydroxymethyl biphenyl.

5. The high-strength impermeable inorganic sealant according to claim 4, characterized in that, The molar ratio of 4,4'-dihydroxybiphenyl, formaldehyde, and sodium hydroxide is 1:4-4.5:2-2.5; the molar amount of glacial acetic acid is the same as the molar amount of sodium hydroxide; and the mass ratio of glacial acetic acid to acetone is 1:5-10.

6. The high-strength impermeable inorganic sealant according to claim 1, characterized in that, The water-reducing agent is a sodium polycarboxylate type water-reducing agent; the dispersant is one or a mixture of several of sodium dodecyl sulfate, sodium lauryl polyoxyethylene ether sulfate, and sodium hexadecyl polyoxyethylene ether phosphate; the pulverization is pulverized to 300-400 mesh.

7. A method for preparing a high-strength impermeable inorganic plugging agent according to any one of claims 1-6, characterized in that, The process includes the following steps: according to the weight ratio, sulfoaluminate cement, gypsum, quicklime, admixture, and water-reducing agent are added to the mixer in sequence and mixed evenly to obtain an inorganic sealant.

8. The method for preparing a high-strength, impermeable inorganic plugging agent according to claim 7, characterized in that, The stirring speed is 600-800 r / min; the stirring time is 20-30 min.

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