Alkali-activated red mud filling material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of mine filling materials, in particular to an alkali-activated red mud filling material and a preparation method and application thereof. The invention provides an alkali-activated red mud filling material, which is prepared from the following raw materials in parts by weight: 70 to 90 parts of red mud, 10 to 20 parts of a dealkalizing agent, 1 to 3 parts of a dealkalizing-coagulating aid, 10 to 30 parts of an auxiliary cementing material, 0.1 to 0.5 part of a retarder, 0.1 to 0.3 part of a water-retaining agent and 0.1 to 0.3 part of an interface reinforcing agent, wherein the weight part of the red mud is the weight part of the dry basis red mud. The alkali-activated red mud filling material prepared by adopting a method combining a dealkalization technology and an alkali-activated technology provided by the invention is faster in coagulation, higher in compressive strength and lower in bleeding rate, meanwhile, the preparation method solves the problems that a large amount of red mud is high in dealkalization cost and difficult to fully utilize after dealkalization, and has great practical application value.

Description

Technical Field

[0001] This invention relates to the field of mine backfill materials technology, and in particular to an alkali-activated red mud backfill material, its preparation method and application. Background Technology

[0002] Red mud is a solid waste generated during the production of alumina from bauxite. It is mainly divided into Bayer process red mud and sintering process red mud, with Bayer process red mud accounting for the largest share, approximately 90% of total red mud production. Its high iron, low calcium, and high alkali characteristics make it difficult to treat and more likely to pollute water and soil. The main components of Bayer process red mud include iron oxide, silicon oxide, and alumina. Its poor hydration activity and high alkali content make it difficult to widely use in the building materials industry. Using Bayer process red mud in backfill materials with lower strength requirements is one way to realize the resource utilization of Bayer process red mud, but this requires solving the problem of its high alkali content. The alkali in red mud not only causes problems such as efflorescence and cracking in backfill materials, but the free alkali in the red mud can also migrate, thus polluting groundwater and soil. Therefore, to realize the application of Bayer process red mud in backfill materials, dealkali treatment of the red mud is essential.

[0003] Currently, dealkali removal methods for red mud mainly include water washing, acid leaching, acid gas neutralization, and calcium ion replacement. However, due to the large output and stockpile of Bayer process red mud, conventional dealkali removal methods present the following practical problems: high cost and potential for secondary pollution; and the challenge of fully utilizing the dealkali-treated red mud. Simply landfilling the dealkali-treated red mud is not only detrimental to resource utilization but also requires significant landfill space. Therefore, simple dealkali removal alone cannot fundamentally solve the problem of insufficient utilization of red mud. Thus, combining red mud dealkali removal with resource utilization, and fully utilizing the products of red mud dealkali removal to achieve resource utilization, is an effective way to solve the red mud problem.

[0004] Furthermore, alkali-activated materials are green cementitious materials formed by activating aluminosilicates as the main component with an alkaline activator. They exhibit characteristics such as early strength, rapid hardening, and resistance to acid and alkali corrosion. The core component of alkali-activated materials is the alkaline activator, which is typically prepared from strongly alkaline materials such as sodium hydroxide, potassium hydroxide, and water glass. However, these strongly alkaline materials are usually expensive, increasing the preparation cost of alkali-activated materials and making them unsuitable for the treatment of large quantities of solid waste. Summary of the Invention

[0005] In view of this, the present invention provides an alkali-activated red mud backfill material, its preparation method and application. The alkali-activated red mud backfill material prepared by combining dealkali technology and alkali activation technology has faster solidification, higher compressive strength and lower water bleeding rate. At the same time, the preparation method solves the problems of high cost of dealkali removal of large amounts of red mud and difficulty in fully utilizing the dealkali removed material, and has great practical application value.

[0006] To solve the above technical problems, the first aspect of the present invention provides an alkali-activated red mud backfill material, which, by weight, comprises: 70-90 parts red mud, 10-20 parts dealkali-removing agent, 1-3 parts dealkali-removing and coagulating aid, 10-30 parts auxiliary cementitious material, 0.1-0.5 parts retarder, 0.1-0.3 parts water-retaining agent, and 0.1-0.3 parts interface enhancer; wherein the weight parts of the red mud are the weight parts of dry red mud.

[0007] The alkali-activated red mud backfill material provided by this invention utilizes a dealkali-removing agent and a dealkali-removing-coagulation aid to displace sodium alkali from the red mud. The displaced sodium alkali is then directly used as an alkali activator to react with auxiliary cementitious materials. Under the combined action of a retarder, water-retaining agent, and interface enhancer, the material solidifies to form the backfill material. This backfill material can be directly used for bauxite backfilling. Furthermore, the main material, red mud, can be largely utilized on-site, solving the problem of large-scale red mud stockpiling and achieving low-cost, high-volume resource utilization of red mud.

[0008] In conjunction with the first aspect, the red mud is Bayer process red mud with a moisture content of less than 40%, preferably 20%-35%.

[0009] The red mud used in the alkali-activated red mud filling material provided by this invention is raw red mud residue, which does not require pre-drying and grinding treatment, greatly reducing the processing cost.

[0010] In conjunction with the first aspect, the dealkali removal agent is selected from at least one of calcium hydroxide, calcium oxide, and carbide slag; the dealkali removal-coagulation aid is selected from at least one of calcium chloride and calcium sulfate.

[0011] The main chemical reactions in the red mud dealkali removal process of this invention are as follows: .

[0012] In conjunction with the first aspect, the auxiliary cementing material is selected from at least one of mineral powder, yellow phosphorus slag powder, fly ash, desulfurized gypsum, and phosphogypsum.

[0013] The auxiliary cementitious material selected in this invention contains silicon and aluminum components. Under the activation effect of sodium hydroxide produced by red mud dealkalization, it can generate an alkali-activated product with a certain strength, thus realizing the simultaneous utilization of red mud and auxiliary cementitious material.

[0014] In conjunction with the first aspect, the specific surface area of ​​the auxiliary cementitious material is not less than 400 m². 2 / kg, preferably 400~600m 2 / kg.

[0015] In conjunction with the first aspect, the retarder is selected from at least one of glucose, sodium citrate, sodium hexametaphosphate, and tartaric acid.

[0016] The retarder used in this invention has excellent retarding properties, which can prevent the material from setting too quickly and causing cracking, while not affecting the strength of the filling material, thus ensuring that the resulting filling material has good comprehensive performance.

[0017] In conjunction with the first aspect, the water-retaining agent is a cellulose compound, a polyacrylamide compound, or calcium stearate; the interface enhancer is selected from at least one of triethylamine, a silane coupling agent, and sodium metasilicate.

[0018] The water-retaining agent selected in this invention can reduce the bleeding rate of filling slurry with high water content, thereby reducing the decrease in fluidity of the filling slurry and the decrease in strength of the filling body caused by bleeding; the interface reinforcing agent used can increase the strength of the interface transition region (the region between the reacted raw materials and the unreacted raw materials) inside the filling material, thereby reducing the influence of the interface transition region on the strength of the filling material.

[0019] In conjunction with the first aspect, the cellulose compound is at least one of hydroxypropyl cellulose, hydroxyethyl cellulose, and carboxymethyl cellulose, and the polyacrylamide compound is at least one of anionic polyacrylamide and nonionic polyacrylamide.

[0020] A second aspect of the present invention provides a method for preparing the above-mentioned alkali-activated red mud backfill material, comprising the following steps: Weigh each raw material according to the formula, add an appropriate amount of water to the red mud to make the liquid-solid ratio 0.3-0.7, and obtain red mud slurry, wherein the weight parts of the red mud are the weight parts of dry red mud. Add a dealkali-removing agent and a dealkali-coagulation aid to the red mud slurry, stir thoroughly for 3-5 minutes, and then continue to shake or stir for 30-60 minutes to obtain a dealkali-removed red mud slurry; Add pre-mixed auxiliary cementitious materials, retarder, water-retaining agent and interface enhancer to the dealkalized red mud slurry, stir thoroughly, and then allow it to solidify naturally to obtain the alkali-activated red mud filling material.

[0021] The method for preparing alkali-activated red mud backfill material provided by the present invention involves adding a dealkali-removing agent and a dealkali-removing-coagulation aid to the red mud. This process removes the sodium alkali from the easily soluble and environmentally polluting sodium silicate slag (main component Na2O·Al2O3·nSiO2·mH2O) in the red mud, causing the sodium silicate slag to generate stable calcium silicate slag (3CaO·Al2O3·nSiO2·(6-2n)H2O). Subsequently, auxiliary cementitious materials are added, using the sodium alkali removed from the red mud as an alkali activator to react with the auxiliary cementitious materials. Under the combined regulation of the dealkali-removing-coagulation aid, water-retaining agent, retarder, and interface enhancer, an alkali-activated cementitious material with a certain strength is generated.

[0022] In conjunction with the second aspect, add an appropriate amount of water to the red mud to make the liquid-solid ratio 0.37-0.67.

[0023] In conjunction with the second aspect, after adding the dealkali agent and dealkali-coagulant aid to the red mud slurry, first stir rapidly for 3-5 minutes to mix the raw materials evenly, and then shake or stir slowly for 30-60 minutes to remove as much sodium alkali as possible from the red mud, ensuring the dealkali removal and activation effects.

[0024] Preferably, the speed of rapid stirring is 400~600 rpm, and the speed of slow stirring is 60~150 rpm.

[0025] The present invention also provides an application of the above-mentioned alkali-activated red mud backfill material or the alkali-activated red mud backfill material prepared according to the above preparation method in the field of backfilling.

[0026] The beneficial effects obtained by this invention are: This invention successfully combines red mud dealkali removal technology with alkali-activated material preparation technology, not only solving the problem of red mud alkali leaching and using raw red mud residue as the main raw material for preparing filling materials, thus realizing the resource utilization of red mud, but also avoiding harm to the soil and water environment, achieving the harmless utilization of red mud. Secondly, this invention combines lime dealkali removal technology with alkali-activated material preparation technology, significantly reducing the cost of activators used in alkali-activated filling materials and enabling the industrial application of activator-based filling materials. Furthermore, the activator system prepared using red mud as raw material can effectively solidify the metal oxides in the red mud, preventing them from harming the environment. In addition, the red mud used in this invention is raw red mud residue generated from alumina production, requiring no pre-drying or grinding; simple mechanical dehydration is sufficient to meet usage requirements, greatly reducing the processing cost of red mud. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the following detailed embodiments are provided. For example, the present invention will be described in further detail. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0028] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined.

[0029] Currently, red mud treatment methods include conventional stockpiling and resource utilization. For conventional stockpiling, to avoid soil and water pollution, it needs to be washed multiple times to remove adhering alkali to meet storage requirements. However, the washed red mud is still highly alkaline, and long-term storage may still have adverse environmental impacts. For resource utilization, it needs dealkalization treatment to prevent equipment corrosion or soil and groundwater pollution. After dealkalization, it also needs to be dried and ground before further use. However, dealkalization treatment is costly, easily causes secondary pollution, and the dealkalized red mud cannot be directly utilized and may still need to be stockpiled for later use.

[0030] In view of this, the present invention provides an alkali-activated red mud backfill material, its preparation method and application. The alkali-activated red mud backfill material is prepared by combining dealkali technology and alkali activation technology. The backfill material sets faster, has higher compressive strength and lower water bleeding rate. At the same time, the preparation method solves the problems of high cost of dealkali removal of large quantities of red mud and difficulty in fully utilizing it after dealkali removal, and has great practical application value.

[0031] The raw materials, reagents, and equipment used in this invention are all conventional commercially available reagents and equipment.

[0032] The red mud used in the following embodiments and comparative examples of this invention is Bayer process red mud with a water content of 23%; the specific surface area of ​​the auxiliary cementitious material used is 500 m². 2 / kg.

[0033] Example 1 This embodiment provides an alkali-activated red mud backfill material, the raw material formula of which is shown in Table 1 below by weight: Table 1

[0034] The preparation method of this alkali-activated red mud backfill material is as follows: Weigh each raw material according to the formula in Table 1, add water to the weighed red mud to obtain red mud slurry (liquid-to-solid ratio 0.47). Add dealkali-removing agent and dealkali-removing coagulant to the red mud slurry, stir rapidly at 500 rpm for 5 minutes to mix thoroughly, then stir slowly at 80 rpm for 45 minutes to obtain dealkali-removed red mud slurry. Add pre-mixed auxiliary cementitious material, retarder, water-retaining agent and interface enhancer to the dealkali-removed red mud slurry, continue stirring at 500 rpm for 5 minutes to mix thoroughly, then allow to solidify naturally to obtain alkali-activated red mud filling material.

[0035] Example 2 This embodiment provides an alkali-activated red mud backfill material, the raw material formula of which is shown in Table 2 below by weight: Table 2

[0036] The preparation method of this alkali-activated red mud backfill material is as follows: Weigh each raw material according to the formula in Table 2, add water to the weighed red mud to obtain red mud slurry (liquid-to-solid ratio 0.47). Add dealkali-removing agent and dealkali-removing coagulant to the red mud slurry, stir rapidly at 450 rpm for 5 minutes to mix thoroughly, then stir slowly at 100 rpm for 40 minutes to obtain dealkali-removed red mud slurry. Add pre-mixed auxiliary cementitious material, retarder, water-retaining agent and interface enhancer to the dealkali-removed red mud slurry, continue stirring at 500 rpm for 5 minutes to mix thoroughly, then allow to solidify naturally to obtain alkali-activated red mud filling material.

[0037] Example 3 This embodiment provides an alkali-activated red mud backfill material, the raw material formula of which is shown in Table 3 below by weight: Table 3

[0038] The preparation method of this alkali-activated red mud backfill material is as follows: Weigh each raw material according to the formula in Table 3, add water to the weighed red mud to obtain red mud slurry (liquid-to-solid ratio 0.37). Add dealkali-removing agent and dealkali-removing coagulant to the red mud slurry, stir rapidly at 550 rpm for 3 minutes to mix thoroughly, then stir slowly at 120 rpm for 30 minutes to obtain dealkali-removed red mud slurry. Add pre-mixed auxiliary cementitious material, retarder, water-retaining agent and interface enhancer to the dealkali-removed red mud slurry, continue stirring at 500 rpm for 5 minutes to mix thoroughly, then allow to solidify naturally to obtain alkali-activated red mud filling material.

[0039] Example 4 This embodiment provides an alkali-activated red mud backfill material, the raw material formula of which is shown in Table 4 below by weight: Table 4

[0040] The preparation method of this alkali-activated red mud backfill material is as follows: Weigh each raw material according to the formula in Table 4, add water to the weighed red mud to obtain red mud slurry (liquid-to-solid ratio 0.67). Add dealkali-removing agent and dealkali-removing coagulant to the red mud slurry, stir rapidly at 500 rpm for 3 minutes to mix thoroughly, then stir slowly at 60 rpm for 60 minutes to obtain dealkali-removed red mud slurry. Add pre-mixed auxiliary cementitious material, retarder, water-retaining agent and interface enhancer to the dealkali-removed red mud slurry, continue stirring at 500 rpm for 5 minutes to mix thoroughly, then allow to solidify naturally to obtain alkali-activated red mud filling material.

[0041] Example 5 This embodiment provides an alkali-activated red mud backfill material, the raw material formula of which is shown in Table 5 below by weight: Table 5

[0042] The preparation method of the alkali-activated red mud backfill material is the same as in Example 1, and will not be repeated here.

[0043] Comparative Example 1 This comparative example provides an alkali-activated red mud backfill material, whose raw material formula is similar to that of Example 1. The only difference is that an equal amount of calcium carbonate is used instead of calcium hydroxide as a dealkali removal agent. The other raw material amounts and the preparation method of the backfill material are the same as those in Example 1, and will not be repeated here.

[0044] Comparative Example 2 This comparative example provides an alkali-activated red mud backfill material, whose raw material formula is similar to that of Example 1. The only difference is that an equal amount of sodium chloride is used instead of calcium chloride, the dealkali-coagulant aid. The other raw material amounts and the preparation method of the backfill material are the same as those in Example 1, and will not be repeated here.

[0045] Comparative Example 3 This comparative example provides an alkali-activated red mud backfill material, whose raw material formula is similar to that of Example 1. The only difference is that an equal amount of PO42.5 cement is used instead of the auxiliary cementitious material mineral powder. The other raw material amounts and the preparation method of the backfill material are the same as those in Example 1, and will not be repeated here.

[0046] Comparative Example 4 This comparative example provides an alkali-activated red mud backfill material, whose raw material formula is similar to that of Example 1. The only difference is that an equal amount of phosphate starch is used instead of the water-retaining agent carboxymethyl cellulose. The other raw material amounts and the preparation method of the backfill material are the same as those in Example 1, and will not be repeated here.

[0047] Comparative Example 5 This comparative example provides an alkali-activated red mud backfill material, whose raw material formula is similar to that of Example 1. The only difference is that the amount of the dealkali agent used is 5 parts. The other raw material amounts and the preparation method of the backfill material are the same as those of Example 1, and will not be repeated here.

[0048] Comparative Example 6 This comparative example provides an alkali-activated red mud backfill material, whose raw material formula is similar to that of Example 1. The only difference is that an equal amount of ammonium chloride is used instead of triethylamine, the interface reinforcing agent. The other raw material amounts and the preparation method of the backfill material are the same as those in Example 1, and will not be repeated here.

[0049] Comparative Example 7 This comparative example provides an alkali-activated red mud backfill material, whose raw material formula is similar to that of Example 1. The only difference is that an equal amount of anhydrous calcium sulfate is used instead of calcium oxide as a dealkali removal agent. The other raw material amounts and the preparation method of the backfill material are the same as those in Example 1, and will not be repeated here.

[0050] Comparative Example 8 This comparative example provides an alkali-activated red mud backfill material, whose raw material formula is similar to that of Example 1. The only difference is that an equal amount of sodium sulfate is used instead of the auxiliary cementing material desulfurized gypsum. The other raw material amounts and the preparation method of the backfill material are the same as those in Example 1, and will not be repeated here.

[0051] Comparative Example 9 This comparative example provides an alkali-activated red mud backfill material, whose raw material formula is similar to that of Example 1. The only difference is that an equal amount of sodium polyacrylate is used instead of carboxymethyl cellulose as the water-retaining agent. The other raw material amounts and the preparation method of the backfill material are the same as those in Example 1, and will not be repeated here.

[0052] Comparative Example 10 This comparative example provides a method for preparing alkali-activated red mud backfill material. The raw material formulation is the same as in Example 1, but the preparation method differs, as detailed below: Weigh each raw material according to the formula in Table 1, add water to the weighed red mud to obtain red mud slurry (liquid-to-solid ratio 0.47). Add dealkali-removing agent and dealkali-removing coagulant to the red mud slurry, and stir rapidly at 500 rpm for 5 minutes to mix thoroughly, obtaining dealkali-removed red mud slurry. Add pre-mixed auxiliary cementitious material, retarder, water-retaining agent and interface enhancer to the dealkali-removed red mud slurry, and continue stirring at 500 rpm for 5 minutes to fully mix the slurry, then allow it to solidify naturally to obtain alkali-activated red mud filling material.

[0053] The difference between this comparative example and the preparation method in Example 1 is that the slow stirring for 30-60 minutes was not performed after adding the dealkali agent and the dealkali-coagulation aid.

[0054] Test Example The performance of the alkali-activated red mud backfill materials obtained in Examples 1-5 and Comparative Examples 1-9 was tested respectively. The initial and final setting times, uniaxial compressive strength and bleeding rate of the backfill materials were tested according to the standard "Technical Standard for Backfill Engineering in Metal and Non-metal Mines" (GB / T51450-2022). The test results are shown in Table 6 below: Table 6

[0055] As can be seen from the material properties of Examples 1-5 in Table 6, the initial setting time of the alkali-activated red mud backfill material provided by this invention can be shortened to less than 10 hours, and the final setting time can reach less than 15 hours. The uniaxial compressive strength on the 7th day and the 28th day can reach as high as 3.0 MPa and 5.0 MPa or more, respectively, and the bleeding rate is as low as close to 3%. This indicates that the material formulation and preparation method provided by this invention can obtain a backfill material with excellent comprehensive performance, while also realizing the resource utilization of red mud, greatly reducing the processing cost, and has great application prospects. In Example 4, due to the relatively high red mud content and the poor activity of the red mud itself, some properties of the obtained backfill material, such as setting time and compressive strength, are not as good as some of the comparative examples.

[0056] Comparing the results of Example 1 with those of Comparative Examples 1-9, it can be seen that when the dealkali-removing agent, dealkali-coagulation aid, auxiliary cementitious material, water-retaining agent, and interface reinforcing agent in Example 1 are replaced with substances other than those specified in this invention, or when the amount of dealkali-removing agent is reduced to 5 parts, the setting time, compressive strength, and bleeding rate of the resulting filling material decrease to varying degrees, and a filling material with good overall performance cannot be obtained. In Comparative Example 10, when the dealkali reaction is not carried out for a certain period of time, the setting time and compressive strength of the resulting filling material both decrease significantly, and the early strength decrease is more obvious. This indicates that insufficient dealkali removal will result in a small amount of NaOH in the red mud that can participate in the alkali-activated reaction, thus failing to fully activate the activity of the auxiliary cementitious material, resulting in a significant decrease in the strength of the filling body. This shows that only by using the formula and preparation method provided by this invention can the perfect combination of red mud dealkali removal and alkali-activated material preparation be achieved, and a filling material with excellent overall performance can be obtained.

[0057] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An alkali-activated red mud backfill material, characterized in that, The raw materials, by weight, include: 70-90 parts red mud, 10-20 parts dealkali-removing agent, 1-3 parts dealkali-coagulation aid, 10-30 parts auxiliary cementitious material, 0.1-0.5 parts retarder, 0.1-0.3 parts water-retaining agent, and 0.1-0.3 parts interface enhancer; wherein, the weight parts of the red mud are the weight parts of dry red mud.

2. The alkali-activated red mud backfill material as described in claim 1, characterized in that, The red mud mentioned is Bayer process red mud with a water content of less than 40%.

3. The alkali-activated red mud backfill material as described in claim 1, characterized in that, The dealkali removal agent is selected from at least one of calcium hydroxide, calcium oxide, and carbide slag; the dealkali removal-coagulation aid is selected from at least one of calcium chloride and calcium sulfate.

4. The alkali-activated red mud backfill material as described in claim 1, characterized in that, The auxiliary cementing material is selected from at least one of mineral powder, yellow phosphorus slag powder, fly ash, desulfurized gypsum, and phosphogypsum.

5. The alkali-activated red mud backfill material as described in claim 4, characterized in that, The specific surface area of ​​the auxiliary cementitious material is not less than 400 m². 2 / kg.

6. The alkali-activated red mud backfill material as described in claim 1, characterized in that, The retarder is selected from at least one of glucose, sodium citrate, sodium hexametaphosphate, and tartaric acid.

7. The alkali-activated red mud backfill material as described in claim 1, characterized in that, The water-retaining agent is a cellulose compound, a polyacrylamide compound, or calcium stearate; the interface enhancer is selected from at least one of triethylamine, silane coupling agent, and sodium metasilicate.

8. The alkali-activated red mud backfill material as described in claim 7, characterized in that, The cellulose compound is at least one of hydroxypropyl cellulose, hydroxyethyl cellulose, and carboxymethyl cellulose, and the polyacrylamide compound is at least one of anionic polyacrylamide and nonionic polyacrylamide.

9. The method for preparing the alkali-activated red mud backfill material according to any one of claims 1-8, characterized in that the step include: Weigh each raw material according to the formula, add an appropriate amount of water to the red mud to make the liquid-solid ratio 0.3-0.7, and obtain red mud slurry, wherein the weight parts of the red mud are the weight parts of dry red mud. Add a dealkali-removing agent and a dealkali-coagulation aid to the red mud slurry, stir thoroughly for 3-5 minutes, and then continue to shake or stir for 30-60 minutes to obtain a dealkali-removed red mud slurry; Add pre-mixed auxiliary cementitious materials, retarder, water-retaining agent and interface enhancer to the dealkalized red mud slurry, stir thoroughly, and then allow it to solidify naturally to obtain the alkali-activated red mud filling material.

10. The application of the alkali-activated red mud backfill material according to any one of claims 1-8 or the alkali-activated red mud backfill material prepared according to the preparation method of claim 9 in the field of backfilling.

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