Preparation process and filling method of double-expansion-source double-layer micro-expansion self-topping sealing material

Abstract

The invention discloses a preparation process and a filling method of a double-expansion-source double-layer micro-expansion self-topping sealing material, and belongs to the technical field of mining filling materials. The double-expansion-source double-layer micro-expansion self-topping sealing material comprises a phase change expansion layer arranged on the lower layer and a chemical foaming expansion layer arranged on the upper layer, wherein the phase change expansion layer is prepared from the following raw materials: slag powder, gypsum, tailings, red mud, a phase change expansion agent and water; the mass ratio of the slag powder to the gypsum to the tailings to the red mud is 40: 25: 10: 25; the addition amount of the phase change expanding agent is 2-12% of the mass of the slag powder; the chemical foaming expansion layer is prepared from the following raw materials: slag powder, a chemical foaming expansion agent, a stabilizer and water; the mass ratio of the slag powder to the chemical foaming expanding agent is 50: (1-4). The double-expansion-source double-layer micro-expansion self-top-forming sealing material can achieve the self-top-forming sealing effect, and the durability, the sealing performance, the strength and other performance are all improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of mine filling materials, and more particularly to a preparation process and filling method of a double-expansion-source double-layer micro-expansion self-closing-top sealing material. BACKGROUND

[0002] The mine sealing wall sealing material is mainly used for quickly constructing a sealing barrier capable of effectively isolating air flow, gas and water underground. The commonly used mine sealing wall sealing material is expanded concrete. The expanded concrete refers to a mixture with an expansion agent, which has expansion characteristics, can improve the compression resistance of the concrete, improve the stress condition of the concrete structure, and reduce the occurrence probability of cracks. The pre-compression stress of the expanded concrete is in a positive proportional relationship with the limited expansion rate, so the control of the pre-compression stress can be realized by adjusting the expansion agent, and the mechanical properties of the expanded concrete are improved after adjustment.

[0003] The expansion methods of the expanded concrete mainly include chemical expansion and physical expansion at present, and the commonly used expansion agents mainly include aluminum oxide powder, aluminum powder and kaolin. Among them: the chemical expansion is realized by adding a chemical expansion agent such as aluminum oxide powder or kaolin, so that part of the slag powder expands and generates bubbles, thereby enhancing the volume stability of the concrete. The physical expansion is realized by adding a particle or fiber material with a certain water absorption, such as slag, expanded clay or lava, so that the volume of the concrete expands. However, the corresponding expansion agent of the chemical expansion has a high price, and problems such as delamination and bubble escape are prone to occur during the mixing and pouring of the concrete. The physical expansion is prone to affect the compactness and strength of the concrete due to the loose particles or fiber materials. Furthermore, the traditional sealing wall has problems of long construction period, easy collapse in water, poor sealing performance due to insufficient self-closing-top capability.

[0004] Therefore, how to provide a micro-expansion mine filling material with reasonable proportion, simple operation, simple process and high economic benefit is a technical problem that those skilled in the art need to solve. SUMMARY

[0005] The purpose of the present application is to provide a preparation process and filling method of a double-expansion-source double-layer micro-expansion self-closing-top sealing material, so as to solve the problems existing in the prior art and realize the effect of greatly reducing the cost under the premise of considering the compressive strength, micro-expansion, self-closing-top and low density.

[0006] To achieve the above-mentioned purpose, the present application provides the following solutions.

[0007] One of the technical solutions of the present application: a double-expansion-source double-layer micro-expansion self-closing-top sealing material is provided, which comprises a phase change expansion layer arranged in a lower layer and a chemical foaming expansion layer arranged in an upper layer:

[0008] The raw material of the phase change expansion layer comprises slag powder, gypsum, tailings, red mud, phase change expansion agent and water; the mass ratio of the slag powder, gypsum, tailings and red mud is 40:25:10:25; and the addition amount of the phase change expansion agent is 2-12% of the mass of the slag powder.

[0009] The raw material of the chemical foaming expansion layer comprises slag powder, chemical foaming expansion agent, stabilizer and water; and the mass ratio of the slag powder and chemical foaming expansion agent is 50:1-4.

[0010] Further, the slag powder is selected from S105 slag powder or S90 slag powder. The slag powder has the characteristics of fast hardening, can quickly undergo hydration reaction, reduces the solidification time and shortens the engineering cycle.

[0011] The slag powder, gypsum, tailings and red mud are selected as the dry material of the phase change expansion layer, wherein CaO and Al2O3 in the slag powder react with water to generate Ca 12 Al 14 O 33 , then reacts with the main component CaSO4·2H2O of the gypsum to generate Ca6Al2(SO4)3(OH) 12 ·26H2O, and the product also has the characteristics of slight expansion. The addition of the tailings and red mud can greatly reduce the cost. In addition, the tailings contain a large amount of fine particles, which can fill the gaps between the material particles, so that the material structure is more compact, thereby improving the compactness and impermeability of the material. The inherent strong alkalinity (rich in NaOH and Na2CO3) of the red mud can be used as a natural alkali activator to activate the activity of the slag powder and other materials.

[0012] Preferably, the phase change expansion agent comprises AEA expansion agent. The AEA expansion agent has good expansion effect, no environmental pollution and high economic benefit. The expansion rate of the AEA expansion agent is moderate, and the cracking problem caused by expansion can be avoided.

[0013] Preferably, the chemical foaming expanding agent is prepared from sodium bicarbonate and fly ash, and the specific steps include: uniformly mixing sodium bicarbonate and fly ash at a mass ratio of 5:15 to obtain the chemical foaming expanding agent. In the chemical foaming expanding agent, sodium bicarbonate can be uniformly wrapped by fly ash, and the mechanical mixing method of step-by-step feeding is adopted in the application. The core idea is to let fly ash as the "wrapping phase" occupy the mixing space first, then add sodium bicarbonate as the "wrapped phase", and use the combined action of shearing and diffusion mixing to achieve the goal of "sodium bicarbonate can be uniformly wrapped by fly ash". The chemical foaming expanding agent mainly generates gas through sodium bicarbonate, releases reaction heat through hydration reaction, promotes gas generation, and the generated gas is wrapped by the slurry and cannot escape, forming bubbles, thereby realizing volume expansion. Through detection, under the conditions of a mass ratio of the slag powder and the chemical foaming expanding agent of 50:1, a temperature of 20℃, and a water-solid ratio of 0.6, the foaming duration of the chemical foaming expanding layer can reach more than 40min, and the volume of the slurry can be increased by more than 20%.

[0014] Preferably, the stabilizer includes one or more of FM500G, sodium stearate and triethanolamine. The addition of the stabilizer can ensure that the expansion time is basically consistent with the slurry setting time, and can reduce the waste caused by slurry outflow.

[0015] Preferably, the addition amount of the stabilizer is 1% of the mass of the chemical foaming expanding agent.

[0016] Preferably, the water-solid ratio of the phase change expanding layer is 0.25-0.65.

[0017] Preferably, the water-solid ratio of the chemical foaming expanding layer is 0.6-0.8.

[0018] The second technical scheme of the application provides a filling method of the double-expansion-source double-layer micro-expansion self-closing top sealing material, which includes the following steps:

[0019] Mixing slag powder, gypsum, tailings, red mud, phase change expanding agent and water uniformly to obtain phase change expanding layer slurry;

[0020] Mixing slag powder, chemical foaming expanding agent, stabilizer and water uniformly to obtain chemical foaming expanding layer slurry;

[0021] Filling the phase change expanding layer slurry to the area needing to be filled first, and then filling the chemical foaming expanding layer slurry.

[0022] Preferably, the chemical foaming expansion layer slurry is filled when the lower phase change expansion layer slurry is in the slurry state. When the lower material is in the slurry state, the upper material is rich in sodium ions and carbonate ions, which diffuse downward in the slurry, and the lower slurry is rich in sulfate ions, which diffuse upward. The thickest transition layer is formed in the contact area, with the strongest interlayer bonding force and the best impact resistance.

[0023] Preferably, the volume ratio of the phase change expansion layer slurry and the chemical foaming expansion layer slurry is 1:5 to 2:4.

[0024] The double expansion source double layer micro-expansion self-capping sealing material of the present application has a double expansion system: the lower layer relies on phase change to expand, and the upper layer promotes expansion through chemical foaming. After pouring, the upper layer rapidly undergoes chemical foaming, has a high expansion rate and expansion ratio, and can quickly achieve preliminary capping; then, under the continuous hydration phase change expansion of the lower layer, the overall structure further expands upward, thereby enhancing the capping effect and ultimately achieving optimal sealing performance.

[0025] The present application discloses the following technical effects:

[0026] The double expansion source double layer micro-expansion self-capping sealing material of the present application can achieve self-capping sealing through double expansion sources, and has improved durability, sealing performance, and strength. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 (a), (b), and (c) are the thickness and morphology of the interlayer transition zone of the material of Example 1, and (d), (e), and (f) are the thickness and morphology of the interlayer transition zone of the material of Example 2;

[0028] Figure 2 (a), (c), and (e) are the X, Y, and Z directions of Example 1, respectively, and (b), (d), and (f) are the X, Y, and Z directions of Example 2, respectively;

[0029] Figure 3 The dry densities of the upper layer materials of Examples 1-6;

[0030] Figure 4 The compressive strengths of the upper layer materials of Examples 1-6;

[0031] Figure 5 The CT three-dimensional reconstruction pore distribution of the material of Example 1;

[0032] Figure 6 The pore size distribution fitting results of the material of Example 1. DETAILED DESCRIPTION

[0033] The following detailed description of various exemplary embodiments of the application will not be considered limiting of the application, but rather a description of certain aspects, features, and embodiments of the application.

[0034] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Additionally, for a range of values of a parameter, unless otherwise stated, each intervening value of the parameter, as well as any other stated or intervening value of the parameter, is encompassed. The intervening values of the parameter are obtained by simply "slicing" or interpolating the range of values of the parameter. The upper and lower limits of these intervening values of the parameter are also encompassed.

[0035] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice of the present application. All documents mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict between the present specification and any document incorporated by reference, the present specification will control.

[0036] Various modifications and changes can be made to the specific embodiments of the application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples presented herein. The description and examples are illustrative of the application and are not intended to limit the scope of the application.

[0037] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean including, but not limited to.

[0038] It should be noted that the present application does not describe in detail the conventional operation means in the art, and is not the focus of the present application.

[0039] The main components of the slag powder, gypsum, tailings, and red mud used in the following examples and comparative examples of the present application are as follows:

[0040] Slag powder:

[0041] Particle size: specific surface area ≥ 420 m 2 / kg (approximately corresponding to d50 ≤ 20 μm).

[0042] Chemical composition (wt%): CaO: 35-45%, SiO2: 30-35%, Al2O3: 10-15%, MgO: 5-10%, and others: ≤ 5%.

[0043] Gypsum:

[0044] Particle size: d50≤50μm, maximum particle size≤200μm.

[0045] Chemical composition (wt%): CaSO4·2H2O:≥85%, SiO2:≤5%, Al2O3:≤2%, Fe2O3:≤1%, crystallization water: 17-19%.

[0046] Tailings:

[0047] Particle size: fineness modulus 1.8-2.2, d50 between 100-150μm.

[0048] Chemical composition (wt%): SiO2:≥70%, Al2O3:5-10%, K2O+Na2O:2-5%, Fe2O3:3-8%, others:≤10%.

[0049] Red mud:

[0050] Particle size: d50≤75μm, irregular particle morphology.

[0051] Chemical composition (wt%): Fe2O3:25-40%, Al2O3:15-20%, SiO2:10-20%, CaO:5-15%, Na2O:4-10%, TiO2:3-8%, loss on ignition (LOI):8-12%.

[0052] The specific steps of the chemical foaming expansion agent (CEA) used are: mixing sodium bicarbonate and fly ash in a mass ratio of 5:15 uniformly to obtain the chemical foaming expansion agent.

[0053] The other raw materials used are commercially available products, and the source of the commercially available products does not affect the technical effects of the present application.

[0054] The room temperature involved in the present application is 25±5℃ unless otherwise specified.

[0055] Example 1

[0056] The present embodiment provides a double-expansion-source double-layer micro-expansion self-closing top sealing material:

[0057] (1) Mix the dry materials of the lower layer expansion material uniformly at room temperature, the dry materials being slag powder, gypsum, tailings, red mud, and phase change AEA expansion agent. The mass ratio of slag powder, gypsum, tailings, and red mud is 40:25:10:25. The addition amount of phase change AEA expansion agent is 4% of the mass of slag powder.

[0058] (2) The upper layer of the expanded material is mixed evenly with dry materials, and FM500G is used as a stabilizer. The dry materials are slag powder and chemical foaming expanding agent. The mass ratio of the slag powder and the chemical foaming expanding agent is 50:1. The amount of the stabilizer added is 1% of the mass of the chemical foaming expanding agent.

[0059] (3) The upper layer of the expanded material and the lower layer of the expanded material are respectively stirred into uniform slurries according to the set water-solid ratio. The water-solid ratio of the lower layer of the slurry is 0.45, and the water-solid ratio of the upper layer of the slurry is 0.6.

[0060] (4) The upper layer of the slurry and the lower layer of the slurry are respectively injected into the flexible membrane bag for pouring by using a continuous pouring device. The lower layer of the slurry is poured first, and the upper layer of the slurry is injected into the lower layer of the slurry to combine with it when the lower layer of the slurry is in the slurry state. The filling volume ratio of the phase change expansion layer slurry to the chemical foaming expansion layer slurry is 1:5.

[0061] Example 2

[0062] The embodiment provides a double-expansion-source double-layer micro-expansion self-closing and sealing material:

[0063] (1) The dry materials of the lower layer of the expanded material are mixed evenly at room temperature. The dry materials are slag powder, gypsum, tailings, red mud, and phase change AEA expanding agent. The mass ratio of the slag powder, the gypsum, the tailings, and the red mud is 40:25:10:25. The amount of the phase change AEA expanding agent added is 2% of the mass of the slag powder.

[0064] (2) The upper layer of the expanded material is mixed evenly with dry materials, and FM500G is used as a stabilizer. The dry materials are slag powder and chemical foaming expanding agent. The mass ratio of the slag powder and the chemical foaming expanding agent is 50:1. The amount of the stabilizer added is 1% of the mass of the chemical foaming expanding agent.

[0065] (3) The upper layer of the expanded material and the lower layer of the expanded material are respectively stirred into uniform slurries according to the set water-solid ratio. The water-solid ratio of the lower layer of the slurry is 0.45, and the water-solid ratio of the upper layer of the slurry is 0.6.

[0066] (4) The upper layer of the slurry and the lower layer of the slurry are respectively injected into the flexible membrane bag for pouring by using a continuous pouring device. The lower layer of the slurry is poured first, and the upper layer of the slurry is injected into the lower layer of the slurry to combine with it when the lower layer of the slurry is in the slurry state. The filling volume ratio of the phase change expansion layer slurry to the chemical foaming expansion layer slurry is 1:5.

[0067] Example 3

[0068] The embodiment provides a double-expansion-source double-layer micro-expansion self-closing and sealing material:

[0069] (1) The dry materials of the lower layer expansion material are mixed uniformly at room temperature, and the dry materials are slag powder, gypsum, tailings, red mud, and phase change AEA expanding agent. The mass ratio of slag powder, gypsum, tailings, and red mud is 40:25:10:25. The addition amount of phase change AEA expanding agent is 8% of the mass of slag powder.

[0070] (2) The dry materials of the upper layer expansion material are mixed uniformly, and FM500G is used as a stabilizer. The dry materials are slag powder and chemical foaming expanding agent. The mass ratio of slag powder and chemical foaming expanding agent is 50:1. The addition amount of stabilizer is 1% of the mass of chemical foaming expanding agent.

[0071] (3) The upper layer expansion material and the lower layer expansion material are respectively stirred into uniform slurry according to the set water-solid ratio. The water-solid ratio of the lower layer slurry is 0.45, and the water-solid ratio of the upper layer slurry is 0.6.

[0072] (4) The upper layer slurry and the lower layer slurry are respectively injected into the flexible membrane bag for pouring by using a continuous pouring device. The lower layer slurry is poured first, and the upper layer slurry is injected and combined with the lower layer slurry when the lower layer slurry is in the slurry state. The filling volume ratio of the phase change expansion layer slurry to the chemical foaming expansion layer slurry is 1:5.

[0073] Example 4

[0074] The embodiment provides a double expansion source double layer micro-expansion self-closing and sealing material:

[0075] (1) The dry materials of the lower layer expansion material are mixed uniformly at room temperature, and the dry materials are slag powder, gypsum, tailings, red mud, and phase change AEA expanding agent. The mass ratio of slag powder, gypsum, tailings, and red mud is 40:25:10:25. The addition amount of phase change AEA expanding agent is 4% of the mass of slag powder.

[0076] (2) The dry materials of the upper layer expansion material are mixed uniformly, and FM500G is used as a stabilizer. The dry materials are slag powder and chemical foaming expanding agent. The mass ratio of slag powder and chemical foaming expanding agent is 50:1. The addition amount of stabilizer is 1% of the mass of chemical foaming expanding agent.

[0077] (3) The upper layer expansion material and the lower layer expansion material are respectively stirred into uniform slurry according to the set water-solid ratio. The water-solid ratio of the lower layer slurry is 0.45, and the water-solid ratio of the upper layer slurry is 0.8.

[0078] (4) The upper layer slurry and the lower layer slurry are respectively injected into the flexible membrane bag for pouring by using a continuous pouring device. The lower layer slurry is poured first, and the upper layer slurry is injected and combined with the lower layer slurry when the lower layer slurry is in the slurry state. The filling volume ratio of the phase change expansion layer slurry to the chemical foaming expansion layer slurry is 1:5.

[0079] Example 5

[0080] The embodiment provides a double-expansion-source double-layer micro-expansion self-closing top sealing material:

[0081] (1) The dry materials of the lower layer expansion material are uniformly mixed at room temperature, and the dry materials are slag powder, gypsum, tailings, red mud and phase change AEA expansion agent. The mass ratio of the slag powder, the gypsum, the tailings and the red mud is 40:25:10:25. The addition amount of the phase change AEA expansion agent is 2% of the mass of the slag powder.

[0082] (2) The dry materials of the upper layer expansion material are uniformly mixed, and FM500G is used as a stabilizer. The dry materials are slag powder and chemical foaming expansion agent. The mass ratio of the slag powder and the chemical foaming expansion agent is 50:1. The addition amount of the stabilizer is 1% of the mass of the chemical foaming expansion agent.

[0083] (3) The upper layer expansion material and the lower layer expansion material are respectively stirred into uniform slurries according to a set water-solid ratio. The water-solid ratio of the lower layer slurry is 0.45, and the water-solid ratio of the upper layer slurry is 0.8.

[0084] (4) A continuous pouring device is used to pour the upper layer slurry and the lower layer slurry into a flexible membrane bag for pouring, the lower layer slurry is poured first, and the upper layer slurry is poured into the lower layer slurry to combine with the lower layer slurry when the lower layer slurry is in a slurry state. The filling volume ratio of the phase change expansion layer slurry to the chemical foaming expansion layer slurry is 1:5.

[0085] Embodiment 6

[0086] The embodiment provides a double-expansion-source double-layer micro-expansion self-closing top sealing material:

[0087] (1) The dry materials of the lower layer expansion material are uniformly mixed at room temperature, and the dry materials are slag powder, gypsum, tailings, red mud and phase change AEA expansion agent. The mass ratio of the slag powder, the gypsum, the tailings and the red mud is 40:25:10:25. The addition amount of the phase change AEA expansion agent is 2% of the mass of the slag powder.

[0088] (2) The dry materials of the upper layer expansion material are uniformly mixed, and FM500G is used as a stabilizer. The dry materials are slag powder and chemical foaming expansion agent. The mass ratio of the slag powder and the chemical foaming expansion agent is 50:1. The addition amount of the stabilizer is 1% of the mass of the chemical foaming expansion agent.

[0089] (3) The upper layer expansion material and the lower layer expansion material are respectively stirred into uniform slurries according to a set water-solid ratio. The water-solid ratio of the lower layer slurry is 0.45, and the water-solid ratio of the upper layer slurry is 0.8.

[0090] (4) using a continuous pouring device, the upper layer slurry and the lower layer slurry are injected into the flexible membrane bag for pouring, the lower layer slurry is poured first, and the upper layer slurry is injected and combined with the lower layer slurry when the lower layer slurry is in the slurry state. The filling volume ratio of the phase change expansion layer slurry and the chemical foaming expansion layer slurry is 1:5.

[0091] Comparative Example 1

[0092] The same as Example 1, the only difference is that the upper layer slurry is injected and combined with the lower layer slurry when the lower layer slurry is in the initial setting state.

[0093] Figure 1 The interlayer transition zone thickness and morphology (a), (b), (c) of the material of Example 1, and the interlayer transition zone thickness and morphology (d), (e), (f) of the material of Comparative Example 1. As shown in Figure 1 CT tests were performed on the materials of Example 1 and Comparative Example 1, and it was found that Example 1 formed a clear transition zone in the contact area of the upper and lower double-layer expansion materials.

[0094] Figure 2 The impact resistance simulation results of the materials of Example 1 and Comparative Example 1, wherein (a), (c), (e) are the X, Y, Z directions of Example 1, respectively, and (b), (d), (f) are the X, Y, Z directions of Comparative Example 1, respectively. Through FLAC 3d The mechanical impact simulation of the air-tight wall found that the air-tight wall of Example 1 was much better than that of Comparative Example 1 in terms of impact resistance, which verified that pouring when the lower layer material is in the slurry state is the best and can have the best interlayer bonding effect.

[0095] Figure 3 The dry density of the upper layer material of Example 1-6.

[0096] Figure 4 The compressive strength of the upper layer material of Example 1-6.

[0097] Figure 5 The CT three-dimensional reconstruction pore distribution of the material of Example 1.

[0098] Figure 6 The pore size distribution fitting result of the material of Example 1.

[0099] The slurry expansion rate, slurry initial setting time, and slurry sustained expansion time of the prepared double-expansion source double-layer micro-expansion self-closing top sealing material were tested.

[0100] Test method: The slurry expansion rate was measured by volume ratio method. The stirred slurry was injected into a test mold with a scale, and the volume of the slurry was recorded every 20 min. Then the expansion rate was calculated according to the ratio method, expansion rate = (slurry volume after expansion-initial slurry volume) / initial slurry volume x 100%. The continuous expansion time of the slurry was calculated according to the expansion rate. When the volume of the slurry did not change continuously for two times, the previous time was recorded as the continuous expansion time of the slurry.

[0101] The initial setting time of the slurry was measured by improved angle method. The slurry was injected into a φ100mmx150mm cylindrical test mold, and the test mold was disturbed every 60s at an angle of 45°. The surface morphology of the slurry was observed. When the slurry interface remained vertical and complete without flowing when tilted to the set angle (45°), it was determined that the initial setting state was reached, and the cumulative time was recorded as the initial setting time.

[0102] Test results:

[0103] Table 1: Slurry expansion rate

[0104]

[0105] The test results in Table 1 show that all the examples have good expansion effect, and the self-closing effect of the top can meet the requirements well. Moreover, the expansion rates of the upper and lower expansion materials of each example can reach a high level, indicating that they have excellent sealing effect.

[0106] In the present specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0107] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual-expansion source dual-layer micro-expansion self-knockdown sealant material, characterized in that, The phase change expansion layer and the chemical foaming expansion layer are included. The raw material of the phase change expansion layer includes slag powder, gypsum, tailings, red mud, phase change expansion agent and water; the mass ratio of the slag powder, gypsum, tailings and red mud is 40:25:10:25; the addition amount of the phase change expansion agent is 2-12% of the mass of the slag powder; The raw material of the chemical foaming expansion layer includes slag powder, chemical foaming expansion agent, stabilizer and water; the mass ratio of the slag powder and chemical foaming expansion agent is 50:1-4.

2. The dual-expansion source dual-layer micro-expansion self-knockdown sealant material of claim 1, wherein, The phase change expansion agent includes AEA expansion agent.

3. The dual-expansion source dual-layer micro-expansion self-knockdown sealant material of claim 1, wherein, The chemical foaming expansion agent is prepared from sodium bicarbonate and fly ash, and the specific steps include: uniformly mixing the sodium bicarbonate and fly ash according to a mass ratio of 5:15 to obtain the chemical foaming expansion agent.

4. The dual-expansion source dual-layer micro-expansion self-knockdown sealant material of claim 1, wherein, The stabilizer includes one or more of FM500G, sodium stearate and triethanolamine.

5. The dual-expansion source dual-layer micro-expansion self-knockdown sealant material of claim 1, wherein, The addition amount of the stabilizer is 1% of the mass of the chemical foaming expansion agent.

6. The dual-expansion source dual-layer micro-expansion self-knockdown sealant material of claim 1, wherein, The water-solid ratio of the phase change expansion layer is 0.25-0.

65.

7. The dual-expansion source dual-layer micro-expansion self-knockdown sealant material of claim 1, wherein, The water-solid ratio of the chemical foaming expansion layer is 0.6-0.

8.

8. A method of filling a dual-expansion source dual-layer micro- expanded self-sealing plug seal material according to any one of claims 1 to 7, characterized in that, The method includes the following steps: uniformly mixing the raw material of the phase change expansion layer to obtain phase change expansion layer slurry; uniformly mixing the raw material of the chemical foaming expansion layer to obtain chemical foaming expansion layer slurry; filling the phase change expansion layer slurry first and then filling the chemical foaming expansion layer slurry in the area to be filled.

9. The filling method according to claim 8, characterized in that, The chemical foaming expansion layer slurry is filled when the phase change expansion layer slurry in the lower layer is in the slurry state.

10. The filling method according to claim 8, wherein The volume ratio of the phase change expansion layer slurry to the chemical foaming expansion layer slurry is 1:5-2:4.

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