Geopolymer grouting material and preparation method thereof

Abstract

The invention relates to a geopolymer grouting material and a preparation method thereof, and relates to the technical field of grouting materials, the geopolymer grouting material comprises the following raw materials by weight: 20-30 parts of red mud, 7-15 parts of fly ash and 50-65 parts of an alkali activator; the alkali activator is composed of a silica fume-based solution and a modified water glass solution in a weight ratio of (15-19): (7-11). On one hand, the red mud is activated and modified by adopting an oxygen-enriched microwave plasma process, and meanwhile, the alkali activator composed of the silica fume-based solution and the modified water glass solution in a specific proportion is matched, so that the properties such as the condensation rate and the mechanical strength of the red mud-fly ash geopolymer are remarkably improved; the use requirement of rapid hardening of the grouting material is met, and the defects of the existing red mud-fly ash geopolymer grouting material are overcome.

Description

Technical Field

[0001] The invention relates to the technical field of grouting materials, and in particular to a geopolymer grouting material and a preparation method thereof. Background Art

[0002] In today's construction and civil engineering fields, grouting materials, as an important engineering material, are widely used in foundation reinforcement, tunnel support, dam anti-seepage and concrete structure repair. Although traditional grouting materials such as cement-based grouting materials are mature and widely used, they have problems such as high energy consumption, large resource consumption and environmental pollution. With the increasing global awareness of sustainable development and environmental protection, the development of new green and high-performance grouting materials has become a hot topic in industry research.

[0003] In recent years, geopolymers, as a new type of inorganic gelling material, have formed polymer compounds with a three-dimensional network structure by stimulating the activity of aluminosilicate minerals, showing certain mechanical properties and durability. Moreover, the raw materials are mostly industrial solid wastes, which are low-carbon, environmentally friendly, low-cost and high-energy. They are considered to be one of the most promising new green gelling materials in the 21st century. The raw materials of geopolymers come from a wide range of sources. Among them, red mud and fly ash, as two major industrial wastes, are rich in aluminosilicate minerals and have potential gelling activity. They can be used as raw materials for preparing geopolymer grouting materials. However, the activity of red mud and fly ash is low. When they are directly used to prepare geopolymer grouting materials, red mud-fly ash geopolymer grouting materials have problems such as slow setting rate and insufficient mechanical strength, which makes it difficult to meet the requirements of actual engineering applications. Therefore, exploring the transformation of industrial wastes such as red mud and fly ash into high-performance grouting materials not only helps to solve environmental problems, but also realizes the recycling of resources, which has important economic and environmental significance. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a geopolymer grouting material and a preparation method thereof.

[0005] In a first aspect, the present invention provides a geopolymer grouting material, which comprises the following raw materials in parts by weight:

[0006] 20-30 parts of red mud, 7-15 parts of fly ash and 50-65 parts of alkali activator;

[0007] The alkali activator is composed of a silica fume-based solution and a modified water glass solution in a weight ratio of (15-19):(7-11).

[0008] Furthermore, the geopolymer grouting material comprises the following raw materials in parts by weight:

[0009] 24 parts of red mud, 10 parts of fly ash and 60 parts of alkali activator.

[0010] Furthermore, the weight ratio of the red mud to the fly ash is 2.4:1.

[0011] Furthermore, the preparation of the silica fume-based solution includes the following process:

[0012] A potassium hydroxide solution with a weight percentage of 40 to 50% and silica fume are stirred and mixed in a weight ratio of (3 to 7): (1 to 3) to obtain the silica fume-based solution.

[0013] Furthermore, the preparation of the modified water glass solution includes the following process:

[0014] The modified water glass solution is obtained by stirring and mixing a water glass solution with a modulus of 2.2-2.5 and polyvinyl alcohol with a polymerization degree of less than 2000 in a weight ratio of (10-15):(3-7).

[0015] Furthermore, the polyvinyl alcohol includes at least one of polyvinyl alcohol 1799 and polyvinyl alcohol 1788.

[0016] Furthermore, the red mud includes at least one of sintered red mud and Bayer process red mud; and the fly ash includes secondary fly ash.

[0017] In a second aspect, the present invention provides a method for preparing the geopolymer grouting material according to any one of the first aspects, the preparation method comprising the following steps:

[0018] Prepare the base activator;

[0019] The red mud is crushed and sieved, and then subjected to oxygen-enriched microwave plasma treatment to obtain modified red mud;

[0020] The modified red mud, fly ash and the alkali activator are stirred and mixed to obtain the geopolymer grouting material.

[0021] Furthermore, the step of oxygen-enriched microwave plasma treatment includes the following process:

[0022] The red mud with a particle size of 300 to 500 mesh after crushing and screening is placed in a microwave plasma treatment instrument, and a mixed gas consisting of oxygen and argon in a volume ratio of 8:1 is used as the working medium. The glow discharge treatment is carried out for 2 to 5 minutes under the conditions that the microwave power is set to 750 to 850 W and the air intake volume is maintained at 100 to 120 mL / min, and then oxygen is continuously introduced for 10 to 15 minutes to obtain the modified red mud.

[0023] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0024] The embodiment of the present invention provides a geopolymer grouting material and a preparation method thereof, specifically a red mud-fly ash geopolymer grouting material. On the one hand, the present invention uses an oxygen-rich microwave plasma process to activate and modify red mud, promotes the recrystallization of the mineral phase in the red mud and the optimization of the microstructure, forms more active surface sites, and thus significantly improves the reactivity of the red mud. The red mud treated with oxygen-rich microwave plasma has enhanced activity, and reacts more fully and rapidly with the alkaline activator, which accelerates the formation of the geopolymer; at the same time, the alkaline activator composed of a specific proportion of silica fume-based solution and modified water glass solution is used to optimize the microstructure of the geopolymer and improve the overall performance of the material. This dual action mechanism significantly improves the properties of the red mud-fly ash geopolymer, such as the setting rate and mechanical strength, meets the use requirements of the grouting material for rapid setting, and makes up for the shortcomings of the existing red mud-fly ash geopolymer grouting materials.

[0025] Therefore, the present invention achieves a significant improvement in the performance of red mud-fly ash geopolymer grouting materials through the synergistic effect of oxygen-rich microwave plasma treatment and a special alkali activator, and also provides a new way for the resource utilization of industrial waste such as red mud, which has significant environmental and economic benefits. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0028] In a first aspect, the present invention provides a geopolymer grouting material, which comprises the following raw materials in parts by weight:

[0029] 20-30 parts of red mud, 7-15 parts of fly ash and 50-65 parts of alkali activator;

[0030] The alkali activator is composed of a silica fume-based solution and a modified water glass solution in a weight ratio of (15-19):(7-11).

[0031] The embodiment of the present invention provides a geopolymer grouting material, specifically a red mud-fly ash geopolymer grouting material. On the one hand, the present invention uses an oxygen-rich microwave plasma process to activate and modify red mud, promotes the recrystallization of the mineral phase in the red mud and the optimization of the microstructure, forms more active surface sites, and thus significantly improves the reactivity of the red mud. The red mud treated with oxygen-rich microwave plasma has enhanced activity, and reacts more fully and rapidly with the alkaline activator, which accelerates the formation of the geopolymer; at the same time, the alkaline activator composed of a specific proportion of silica fume-based solution and a modified water glass solution is combined, and by adjusting the Si / Al ratio in the solution, the components in the alkaline activator optimize the microstructure of the geopolymer and improve the overall performance of the material. This dual action mechanism significantly improves the properties of the red mud-fly ash geopolymer, such as the setting rate and mechanical strength, meets the use requirements of the grouting material for rapid setting, and makes up for the shortcomings of the existing red mud-fly ash geopolymer grouting materials.

[0032] In some specific embodiments, the geopolymer grouting material comprises the following raw materials in parts by weight:

[0033] 24 parts of red mud, 10 parts of fly ash and 60 parts of alkali activator.

[0034] In some specific embodiments, the weight ratio of the red mud to the fly ash is 2.4:1.

[0035] In some specific embodiments, the alkali activator is composed of a silica fume-based solution and a modified water glass solution in a weight ratio of 17:9.

[0036] In some specific embodiments, the preparation of the silica fume-based solution includes the following process:

[0037] A potassium hydroxide solution with a weight percentage of 40 to 50% and silica fume are stirred and mixed in a weight ratio of (3 to 7): (1 to 3) to obtain the silica fume-based solution. Preferably, the weight ratio of the potassium hydroxide solution to the silica fume is 5:2.

[0038] In some specific embodiments, the preparation of the modified water glass solution includes the following process:

[0039] The modified water glass solution is obtained by mixing a water glass solution having a modulus of 2.2-2.5 and a polyvinyl alcohol having a degree of polymerization of less than 2000 in a weight ratio of (10-15):(3-7). Preferably, the weight ratio of the water glass solution to the polyvinyl alcohol is 13:5.

[0040] In some specific embodiments, the polyvinyl alcohol includes at least one of polyvinyl alcohol 1799 and polyvinyl alcohol 1788.

[0041] In some specific embodiments, the water glass solution can be directly a commercial product with a corresponding modulus, or can be homemade according to the modulus preparation method of the water glass solution disclosed in CN 110467187A to obtain a water glass solution with a modulus of 2.2-2.5.

[0042] In some specific embodiments, the red mud includes at least one of sintered red mud and Bayer process red mud, preferably sintered red mud; and the fly ash includes secondary fly ash.

[0043] It should be noted that the component raw materials involved in the geopolymer grouting material provided in the embodiment of the present invention, unless otherwise specified or specified, such as red mud, fly ash, potassium hydroxide solution, silica fume, polyvinyl alcohol and the like, can be directly commercially available products or made in-house according to the methods disclosed in the prior art, and will not be described in detail here.

[0044] In a second aspect, based on a general inventive concept, the present invention provides a method for preparing the geopolymer grouting material according to any one of the first aspects, the preparation method comprising the following steps:

[0045] Prepare the base activator;

[0046] The red mud is crushed and sieved, and then subjected to oxygen-enriched microwave plasma treatment to obtain modified red mud;

[0047] The modified red mud, fly ash and the alkali activator are stirred and mixed to obtain the geopolymer grouting material.

[0048] The method for preparing the geopolymer grouting material provided in the embodiment of the present invention is implemented based on the geopolymer grouting material described in any one of the first aspects above, and therefore has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0049] In some specific embodiments, the step of oxygen-rich microwave plasma treatment includes the following process:

[0050] The red mud with a particle size of 300 to 500 mesh after crushing and screening is placed in a microwave plasma treatment instrument, and a mixed gas consisting of oxygen and argon in a volume ratio of 8:1 is used as the working medium. The glow discharge treatment is carried out for 2 to 5 minutes under the conditions that the microwave power is set to 750 to 850 W and the air intake volume is maintained at 100 to 120 mL / min, and then oxygen is continuously introduced for 10 to 15 minutes to obtain the modified red mud.

[0051] It should be noted that the operation steps involved in the preparation method of the geopolymer grouting material provided in the embodiment of the present invention, unless otherwise specified or explained, can be carried out according to the preparation process disclosed in the prior art or using existing equipment, and will not be described one by one here.

[0052] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0053] Example 1

[0054] This example provides a geopolymer grouting material, which includes the following raw materials in parts by weight:

[0055] 24 parts of red mud, 10 parts of fly ash and 60 parts of alkali activator;

[0056] The red mud is sintered red mud;

[0057] The fly ash is secondary fly ash;

[0058] The alkaline activator is composed of a silica fume-based solution and a modified water glass solution in a weight ratio of 17:9;

[0059] The preparation of the silica fume-based solution includes the following process: stirring and mixing a potassium hydroxide solution with a weight percentage of 45% and silica fume in a weight ratio of 5:2 to obtain the silica fume-based solution;

[0060] The preparation of the modified water glass solution includes the following process: stirring and mixing a water glass solution with a modulus of 2.4 and polyvinyl alcohol 1788 in a weight ratio of 13:5 to obtain the modified water glass solution.

[0061] The preparation method of the above-mentioned geopolymer grouting material comprises the following steps:

[0062] Step (1): preparing an alkali activator;

[0063] Step (2): crushing and sieving the red mud to obtain red mud with a particle size of 400 mesh; then placing the crushed and sifted red mud with a particle size of 400 mesh in a microwave plasma treatment instrument, using a mixed gas consisting of oxygen and argon in a volume ratio of 8:1 as a working medium, setting the microwave power to 800 W and maintaining the air intake at 115 mL / min for glow discharge treatment for 3.5 minutes, and then continuously introducing oxygen for 10 minutes to obtain the modified red mud;

[0064] Step (3): stirring and mixing the modified red mud, fly ash and the alkali activator to obtain the geopolymer grouting material.

[0065] Example 2

[0066] This example provides a geopolymer grouting material, which includes the following raw materials in parts by weight:

[0067] 20 parts of red mud, 7 parts of fly ash and 50 parts of alkali activator;

[0068] The red mud is sintered red mud;

[0069] The fly ash is secondary fly ash;

[0070] The alkaline activator is composed of a silica fume-based solution and a modified water glass solution in a weight ratio of 15:7;

[0071] The preparation of the silica fume-based solution includes the following process: stirring and mixing a potassium hydroxide solution with a weight percentage of 40% and silica fume in a weight ratio of 7:3 to obtain the silica fume-based solution;

[0072] The preparation of the modified water glass solution includes the following process: stirring and mixing a water glass solution with a modulus of 2.2 and polyvinyl alcohol 1799 in a weight ratio of 10:3 to obtain the modified water glass solution.

[0073] The preparation method of the above-mentioned geopolymer grouting material comprises the following steps:

[0074] Step (1): preparing an alkali activator;

[0075] Step (2): crushing and sieving the red mud to obtain red mud with a particle size of 400 mesh; then placing the crushed and sifted red mud with a particle size of 400 mesh in a microwave plasma treatment instrument, using a mixed gas consisting of oxygen and argon in a volume ratio of 8:1 as a working medium, setting the microwave power to 750 W and maintaining the air intake at 100 mL / min for glow discharge treatment for 5 minutes, and then continuously introducing oxygen for 15 minutes to obtain the modified red mud;

[0076] Step (3): stirring and mixing the modified red mud, fly ash and the alkali activator to obtain the geopolymer grouting material.

[0077] Example 3

[0078] This example provides a geopolymer grouting material, which includes the following raw materials in parts by weight:

[0079] 30 parts of red mud, 15 parts of fly ash and 65 parts of alkali activator;

[0080] The red mud is sintered red mud;

[0081] The fly ash is secondary fly ash;

[0082] The alkaline activator is composed of a silica fume-based solution and a modified water glass solution in a weight ratio of 19:11;

[0083] The preparation of the silica fume-based solution includes the following process: stirring and mixing a potassium hydroxide solution with a weight percentage of 50% and silica fume in a weight ratio of 3:1 to obtain the silica fume-based solution;

[0084] The preparation of the modified water glass solution includes the following process: stirring and mixing a water glass solution with a modulus of 2.5 and polyvinyl alcohol 1799 in a weight ratio of 15:7 to obtain the modified water glass solution.

[0085] The preparation method of the above-mentioned geopolymer grouting material comprises the following steps:

[0086] Step (1): preparing an alkali activator;

[0087] Step (2): crushing and sieving the red mud to obtain red mud with a particle size of 400 mesh; then placing the crushed and sifted red mud with a particle size of 400 mesh in a microwave plasma treatment instrument, using a mixed gas consisting of oxygen and argon in a volume ratio of 8:1 as a working medium, performing glow discharge treatment for 2 minutes under the conditions of microwave power set to 850 W and air intake maintained at 120 mL / min, and then continuously introducing oxygen for 10 minutes to obtain the modified red mud;

[0088] Step (3): stirring and mixing the modified red mud, fly ash and the alkali activator to obtain the geopolymer grouting material.

[0089] Comparative Example 1

[0090] This example provides a geopolymer grouting material and a preparation method thereof, which differs from Example 1 only in that the red mud is not subjected to the oxygen-enriched plasma treatment in step (2); the remaining steps and parameters are the same.

[0091] This example provides a geopolymer grouting material, which includes the following raw materials in parts by weight:

[0092] 24 parts of red mud, 10 parts of fly ash and 60 parts of alkali activator;

[0093] The red mud is sintered red mud;

[0094] The fly ash is secondary fly ash;

[0095] The alkaline activator is composed of a silica fume-based solution and a modified water glass solution in a weight ratio of 17:9;

[0096] The preparation of the silica fume-based solution includes the following process: stirring and mixing a potassium hydroxide solution with a weight percentage of 45% and silica fume in a weight ratio of 5:2 to obtain the silica fume-based solution;

[0097] The preparation of the modified water glass solution includes the following process: stirring and mixing a water glass solution with a modulus of 2.4 and polyvinyl alcohol 1788 in a weight ratio of 13:5 to obtain the modified water glass solution.

[0098] The preparation method of the above-mentioned geopolymer grouting material comprises the following steps:

[0099] Step (1): preparing an alkali activator;

[0100] Step (2): stirring and mixing red mud, fly ash and the alkali activator to obtain the geopolymer grouting material.

[0101] Comparative Example 2

[0102] This example provides a geopolymer grouting material and a preparation method thereof, which is different from Example 1 only in that the alkali activator is composed only of a silica fume-based solution; the remaining steps and parameters are the same.

[0103] This example provides a geopolymer grouting material, which includes the following raw materials in parts by weight:

[0104] 24 parts of red mud, 10 parts of fly ash and 60 parts of alkali activator;

[0105] The red mud is sintered red mud;

[0106] The fly ash is secondary fly ash;

[0107] The alkaline activator is a silica fume-based solution;

[0108] The preparation of the silica fume-based solution includes the following process: stirring and mixing a potassium hydroxide solution with a weight percentage of 45% and silica fume in a weight ratio of 5:2 to obtain the silica fume-based solution.

[0109] The preparation method of the above-mentioned geopolymer grouting material comprises the following steps:

[0110] Step (1): preparing an alkali activator;

[0111] Step (2): crushing and sieving the red mud to obtain red mud with a particle size of 400 mesh; then placing the crushed and sifted red mud with a particle size of 400 mesh in a microwave plasma treatment instrument, using a mixed gas consisting of oxygen and argon in a volume ratio of 8:1 as a working medium, setting the microwave power to 800 W and maintaining the air intake at 115 mL / min for glow discharge treatment for 3.5 minutes, and then continuously introducing oxygen for 10 minutes to obtain the modified red mud;

[0112] Step (3): stirring and mixing the modified red mud, fly ash and the alkali activator to obtain the geopolymer grouting material.

[0113] Comparative Example 3

[0114] This example provides a geopolymer grouting material and a preparation method thereof, which is different from Example 1 only in that the weight fraction of the red mud is adjusted to 10 parts, and the weight fraction of the fly ash is adjusted to 24 parts; the remaining steps and parameters are the same.

[0115] This example provides a geopolymer grouting material, which includes the following raw materials in parts by weight:

[0116] 10 parts of red mud, 24 parts of fly ash and 60 parts of alkali activator;

[0117] The red mud is sintered red mud;

[0118] The fly ash is secondary fly ash;

[0119] The alkaline activator is composed of a silica fume-based solution and a modified water glass solution in a weight ratio of 17:9;

[0120] The preparation of the silica fume-based solution includes the following process: stirring and mixing a potassium hydroxide solution with a weight percentage of 45% and silica fume in a weight ratio of 5:2 to obtain the silica fume-based solution;

[0121] The preparation of the modified water glass solution includes the following process: stirring and mixing a water glass solution with a modulus of 2.4 and polyvinyl alcohol 1788 in a weight ratio of 13:5 to obtain the modified water glass solution.

[0122] The preparation method of the above-mentioned geopolymer grouting material comprises the following steps:

[0123] Step (1): preparing an alkali activator;

[0124] Step (2): crushing and sieving the red mud to obtain red mud with a particle size of 400 mesh; then placing the crushed and sifted red mud with a particle size of 400 mesh in a microwave plasma treatment instrument, using a mixed gas consisting of oxygen and argon in a volume ratio of 8:1 as a working medium, setting the microwave power to 800 W and maintaining the air intake at 115 mL / min for glow discharge treatment for 3.5 minutes, and then continuously introducing oxygen for 10 minutes to obtain the modified red mud;

[0125] Step (3): stirring and mixing the modified red mud, fly ash and the alkali activator to obtain the geopolymer grouting material.

[0126] Test Case

[0127] In this example, the geopolymer grouting materials prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were tested for performance according to the test method disclosed in the prior art. The initial setting time and the final setting time were tested by taking part of the mixed slurry during the preparation process. After the remaining mixture was made into a standard test mold, the test mold was laid flat for 24 hours at 25-30°C for demoulding, and the compressive strength was tested after curing for 28 days. The results are shown in Table 1.

[0128] Table 1

[0129]

[0130]

[0131] It can be seen from Table 1 that, compared with the comparative example, the geopolymer grouting material provided by the embodiment of the present invention has the characteristics of fast setting rate and high compressive strength, and can meet the use requirements of rapid setting of grouting materials.

[0132] In summary, the embodiments of the present invention provide a geopolymer grouting material and a preparation method thereof. On the one hand, the present invention activates and modifies red mud by adopting an oxygen-rich microwave plasma process, and at the same time, an alkali activator composed of a silica fume-based solution and a modified water glass solution in a specific proportion is used to significantly improve the coagulation rate and mechanical strength of the red mud-fly ash geopolymer, meet the use requirements of the grouting material for rapid setting, and make up for the shortcomings of the existing red mud-fly ash geopolymer grouting materials.

[0133] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A geopolymer grouting material, characterized in that: The geopolymer grouting material comprises the following raw materials in parts by weight: 20-30 parts of red mud, 7-15 parts of fly ash and 50-65 parts of alkali activator; The alkali activator is composed of a silica fume-based solution and a modified water glass solution in a weight ratio of (15-19):(7-11).

2. The geopolymer grouting material according to claim 1, characterized in that: The geopolymer grouting material comprises the following raw materials in parts by weight: 24 parts of red mud, 10 parts of fly ash and 60 parts of alkali activator.

3. The geopolymer grouting material according to claim 1, characterized in that: The weight ratio of the red mud to the fly ash is 2.4:

1.

4. The geopolymer grouting material according to any one of claims 1 to 3, characterized in that: The preparation of the silica fume-based solution includes the following processes: A potassium hydroxide solution with a weight percentage of 40 to 50% and silica fume are stirred and mixed in a weight ratio of (3 to 7): (1 to 3) to obtain the silica fume-based solution.

5. The geopolymer grouting material according to any one of claims 1 to 3, characterized in that: The preparation of the modified water glass solution comprises the following process: The modified water glass solution is obtained by stirring and mixing a water glass solution with a modulus of 2.2-2.5 and polyvinyl alcohol with a degree of polymerization less than 2000 in a weight ratio of (10-15):(3-7).

6. The geopolymer grouting material according to claim 5, characterized in that: The polyvinyl alcohol includes at least one of polyvinyl alcohol 1799 and polyvinyl alcohol 1788.

7. The geopolymer grouting material according to claim 1, characterized in that: The red mud includes at least one of sintered red mud and Bayer red mud; and the fly ash includes secondary fly ash.

8. A method for preparing the geopolymer grouting material according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: Prepare the base activator; The red mud is crushed and sieved, and then subjected to oxygen-enriched microwave plasma treatment to obtain modified red mud; The modified red mud, fly ash and the alkali activator are stirred and mixed to obtain the geopolymer grouting material.

9. The method for preparing the geopolymer grouting material according to claim 8, characterized in that: The steps of oxygen-rich microwave plasma treatment include the following processes: The red mud with a particle size of 300 to 500 mesh after crushing and screening is placed in a microwave plasma treatment instrument, and a mixed gas consisting of oxygen and argon in a volume ratio of 8:1 is used as the working medium. The glow discharge treatment is carried out for 2 to 5 minutes under the conditions that the microwave power is set to 750 to 850 W and the air intake volume is maintained at 100 to 120 mL / min, and then oxygen is continuously introduced for 10 to 15 minutes to obtain the modified red mud.

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