An adaptive microcapsule system, and a preparation method and application thereof

Abstract

This invention belongs to the field of fully mechanized longwall mining safety technology, and provides an adaptive microcapsule system, its preparation method, and its application. A pectin-sodium alginate solution and a calcium chloride solution are mixed and crosslinked to obtain a wall material emulsion; perfluorohexanone is mixed with the wall material emulsion to obtain an inner layer emulsion; the inner layer emulsion is mixed with a chitosan emulsion to obtain a double-layer wall material emulsion; the double-layer wall material emulsion is mixed with a glutaraldehyde solution to obtain microcapsules; and the microcapsules are mixed with a saponin solution to obtain the final product. In this invention, boreholes are arranged in the intake and return airways, and injection pipelines are installed in the boreholes, which are then sealed to a sealing device. Before coal discharge, the adaptive microcapsule system is injected into the original coal seam; during coal discharge, the adaptive microcapsule system falls naturally, and the saponin solution increases the temperature difference between the coal and gangue, identifying the gangue; after coal discharge, the microcapsules adhere to the surface of the remaining coal and fall into the goaf together, preventing spontaneous combustion.

Description

Technical Field

[0001] This invention relates to the field of fully mechanized longwall mining safety technology, and in particular to an adaptive microcapsule system, its preparation method, and its application. Background Technology

[0002] Fully mechanized longwall mining is a key technology in the coal mining industry. Currently, the main technical problems in fully mechanized longwall mining are dust pollution, preventing spontaneous combustion of residual coal in the goaf, difficulty in identifying coal and gangue, and the lack of integrated management methods. Three major technical problems have long existed in fully mechanized longwall mining: First, a large amount of dust is generated during top coal crushing and transportation, of which respirable dust accounts for more than 40%. Long-term inhalation of this dust by underground workers can easily lead to occupational diseases such as pneumoconiosis, seriously threatening the health of miners. Traditional spray dust suppression, while low in cost, is difficult to achieve sufficient penetration, resulting in incomplete dust suppression and short-lived effects. While chemical dust suppressants can improve dust suppression in the short term, long-term use can lead to seepage into the ground, causing secondary environmental pollution. Second, after coal is released in fully mechanized longwall mining, residual coal falls into the goaf. When heat accumulates to the ignition point of the residual coal, it can spontaneously combust, potentially triggering secondary disasters such as gas explosions, seriously threatening the safety of underground workers. Control technologies such as nitrogen injection or flame retardant spraying require a continuous supply of anti-spontaneous combustion materials to the goaf, and necessitate specialized equipment and monitoring systems, resulting in excessively high control costs per ton of coal. Thirdly, underground coal and gangue identification is difficult; traditional methods relying on manual labor or video images have low accuracy, high labor intensity, and low sorting efficiency. This leads to gangue being mixed into the coal product, wasting high-quality coal resources. Furthermore, addressing these three major problems in a phased manner requires significant additional manpower and resources, involves cumbersome construction processes, extends the mining cycle, and increases construction costs.

[0003] One practical solution involves an in-situ dust suppression method and material for reducing dust during coal seam mining (202211694390.8). This method injects a highly permeable, fluid, and gelling material into the original coal seam. The material penetrates into the coal seam's fissures and pores, cross-linking to form a three-dimensional network of flexible water-retaining material, altering the coal's toughness and moisture content, thus reducing dust generation during coal mining. However, this solution has the following drawbacks: First, it requires the injection of components A and B in two stages, relying on the coal seam's fissure and pore environment for mixing and reaction. If the coal seam's pore distribution is uneven or the fissure connectivity is poor, the two components may not contact sufficiently, resulting in incomplete reaction and affecting gel formation, thus reducing local dust suppression efficiency. Second, the gel formed after mixing components A and B adheres to the coal surface, increasing the impurity content in the coal, and subsequent washing and beneficiation processes require additional reagents or equipment to remove residual gel. Third, it has a single function, lacking other dust suppression capabilities; the final product only functions in dust suppression, increasing relative costs.

[0004] Therefore, traditional methods such as spraying dust, injecting nitrogen or spraying flame retardants, and relying on manual methods or video images cannot meet the needs of collaborative governance. Currently, there are no relevant technical solutions for collaborative governance of dust pollution, prevention and control of spontaneous combustion of coal residues in goaf areas, and identification of coal gangue. Summary of the Invention

[0005] The purpose of this invention is to overcome the deficiencies in the prior art and provide an adaptive microcapsule system, its preparation method, and its application.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing an adaptive microcapsule system, comprising the following steps: (1) A wall material emulsion is obtained by mixing and crosslinking pectin-sodium alginate solution and calcium chloride solution; (2) The inner layer emulsion is obtained by mixing perfluorohexanone and the wall material emulsion; (3) Mix the inner layer emulsion and the chitosan emulsion to obtain a double-layer wall material emulsion; (4) Mix the double-layer wall material emulsion and glutaraldehyde solution to obtain microcapsules; (5) Mix the microcapsules and saponin solution to obtain the adaptive microcapsule system.

[0007] Preferably, the mass ratio of pectin to sodium alginate in step (1) is 2~4:1; The pectin concentration in the pectin-sodium alginate solution is 0.5%~1.5% by mass. The mass concentration of the calcium chloride solution is 0.1%~1%; The volume ratio of pectin-sodium alginate solution to calcium chloride solution is 8~12:1; The crosslinking time in step (1) is ≥30 min; In step (2), the mass ratio of perfluorohexanone to wall material emulsion is 1:4~6; In step (2), the mixing temperature is 35~45℃, the time is ≥60min, and the rotation speed is ≥1500rpm.

[0008] Preferably, the chitosan emulsion in step (3) comprises chitosan, emulsifier, water and acetic acid solution; The mass ratio of chitosan, emulsifier and water is 8~12:2~4:100; The concentration of the acetic acid solution is 2-4%; the pH of the chitosan emulsion is 2-4. In step (3), the volume ratio of the inner emulsion to the chitosan emulsion is 1:3~4; In step (3), the mixing temperature is 45~55℃ and the time is ≥60min.

[0009] Preferably, the mass concentration of the glutaraldehyde solution in step (4) is 10-30%; In step (4), the volume ratio of the double-layer wall material emulsion to the glutaraldehyde solution is 80~100:1; In step (4), the mixing temperature is 45~55℃ and the time is ≥3h.

[0010] Preferably, the concentration of the saponin solution in step (5) is 0.03~0.15%; In step (5), the mass of the microcapsules is 3-5% of the mass of the saponin solution.

[0011] The present invention also provides a method for preparing the adaptive microcapsule system to obtain the adaptive microcapsule system.

[0012] The present invention also provides the application of the adaptive microcapsule system in coal seam mining.

[0013] This invention also provides an in-situ dust suppression method for coal seam mining dust, comprising the following steps: (a) Drill holes are arranged in the intake airway and return airway, and injection lines are installed in the drill holes. The injection lines are connected to the sealing device in a closed manner. (b) Inject the adaptive microcapsule system into the original coal seam before coal release; (c) The adaptive microcapsule system naturally descends during coal discharge, and the saponin solution increases the temperature difference between coal and coal gangue, thus identifying coal gangue; (d) After coal is released, the microcapsules adhere to the surface of the remaining coal and fall into the goaf together to prevent spontaneous combustion.

[0014] Preferably, in step (a), the distance between two adjacent boreholes is 10-15m, and the borehole depth is 50-150m.

[0015] Preferably, the grouting pressure injected in step (b) is 3~5MPa.

[0016] This invention provides a method for preparing an adaptive microcapsule system, comprising the following steps: mixing and crosslinking a pectin-sodium alginate solution and a calcium chloride solution to obtain a wall material emulsion; mixing perfluorohexanone and the wall material emulsion to obtain an inner layer emulsion; mixing the inner layer emulsion and a chitosan emulsion to obtain a double-layer wall material emulsion; mixing the double-layer wall material emulsion and a glutaraldehyde solution to obtain microcapsules; and mixing the microcapsules and a saponin solution to obtain the adaptive microcapsule system. This invention also applies the adaptive microcapsule system to coal seam mining. Boreholes are arranged in the intake and return airways, and injection pipelines are installed inside the boreholes, which are then sealed to a sealing device. Before coal discharge, the adaptive microcapsule system is injected into the original coal seam. During coal discharge, the adaptive microcapsule system falls naturally, and the saponin solution increases the temperature difference between the coal and gangue, identifying the gangue. After coal discharge, the microcapsules adhere to the surface of the remaining coal and fall into the goaf, preventing spontaneous combustion.

[0017] This invention involves injecting a mixture of microcapsules and saponin solution into the coal seam before coal discharge in fully mechanized longwall mining. This mixture acts as a wetting agent, pre-suppressing dust during coal breakage and controlling the risk of spontaneous combustion at its source. During coal discharge, the outer wall material, made of chitosan, adsorbs and disperses dust particles for secondary dust reduction. A portion of the low-temperature saponin solution is sprayed to increase the temperature difference between coal and gangue. Based on liquid-intervention infrared thermal imaging recognition technology, this significantly improves the accuracy and efficiency of coal and gangue sorting. After coal discharge, the microcapsules fall into the goaf with the remaining coal. When the goaf reaches a certain temperature, the inner temperature-sensitive wall material disintegrates, and perfluorohexanone is heated and breaks through the wall material, thus preventing spontaneous combustion of the remaining coal.

[0018] The adaptive microcapsule system provided by this invention premixes microcapsules with saponin solution into a single system. The operation can be completed by injecting the mixture into the coal seam through drilling before coal discharge. The injection process is simple and efficient. The mixed material can fully penetrate the pores and fissures of the coal seam, which not only ensures the stable and uniform pretreatment effect of dust suppression and flame retardancy, but also simplifies the construction operation and avoids the problem of insufficient local treatment efficiency.

[0019] This invention innovatively breaks through the limitations of the "separate treatment" approach of dust suppression, flame retardancy, and coal and gangue identification in fully mechanized longwall mining. Through a double-layer wall material design, it achieves the adaptive properties of microcapsules. Different wall materials have clearly defined functions in different scenarios. The outer wall material, chitosan, ensures the stability of the capsule structure and adsorbs dust particles. The inner wall material, formed by pectin and sodium alginate, possesses temperature-sensitive response characteristics, establishing a temperature-triggered flame retardancy mechanism. When the residual coal in the goaf oxidizes and heats up to a preset critical temperature, the temperature-sensitive wall material, cross-linked with pectin and sodium alginate, disintegrates, and the encapsulated perfluorohexanone is rapidly released and diffuses. By isolating oxygen, absorbing heat, and inhibiting the combustion chain reaction, it achieves precise flame retardancy, providing timely and reliable technical support for fire prevention and control in coal mine goafs. This overcomes the technical bottleneck of existing single-wall material microcapsules with fixed functions, which cannot adapt to the needs of multiple scenarios throughout the entire process.

[0020] Microcapsules combined with natural saponin solution are injected into the coal seam through boreholes before coal mining operations. This not only enhances the wetting and dispersion of coal dust and the adhesion of microcapsules, but also increases the difference in surface characteristics between coal and gangue. Ultimately, this achieves adaptive dust adsorption, coal and gangue identification, and coordinated control of spontaneous combustion of residual coal in goaf areas, significantly improving the intelligence and precision of disaster prevention and control in fully mechanized longwall mining.

[0021] This invention, through a synergistic design of "microcapsules + saponin solution," provides a one-stop solution to three core problems in fully mechanized longwall mining: dust pollution, spontaneous combustion of residual coal in goaf, and difficulty in identifying coal and gangue. It eliminates the need for separate dust suppression, flame retardant, and coal and gangue identification equipment and construction teams, significantly reducing equipment investment and labor costs, simplifying the construction process, shortening the mining cycle, and significantly improving the overall efficiency and economic benefits of fully mechanized longwall mining. Furthermore, the microcapsule wall materials used in this invention are all natural polymer materials with good biodegradability, biocompatibility, and non-toxicity, and do not leave harmful impurities on the coal surface. Subsequent washing and beneficiation processes do not require additional reagents or equipment to treat residual substances, ensuring the purity of the coal product and reducing subsequent processing costs. Attached Figure Description

[0022] Figure 1 This is a flowchart of the preparation method of the adaptive microcapsule system of the present invention; Figure 2 This is a schematic diagram of the coal seam mining construction process according to the present invention; Figure 3 This is a schematic diagram of the adaptive microcapsule system synergistic processing during the coal discharge process of the present invention. Detailed Implementation

[0023] This invention provides a method for preparing an adaptive microcapsule system, comprising the following steps: (1) A wall material emulsion is obtained by mixing and crosslinking pectin-sodium alginate solution and calcium chloride solution; (2) The inner layer emulsion is obtained by mixing perfluorohexanone and the wall material emulsion; (3) Mix the inner layer emulsion and the chitosan emulsion to obtain a double-layer wall material emulsion; (4) Mix the double-layer wall material emulsion and glutaraldehyde solution to obtain microcapsules; (5) Mix the microcapsules and saponin solution to obtain the adaptive microcapsule system.

[0024] In this invention, the mass ratio of pectin to sodium alginate in step (1) is preferably 2~4:1, more preferably 2.5~3.5:1, and even more preferably 2.8~3.2:1.

[0025] In this invention, the pectin mass concentration in the pectin-sodium alginate solution is preferably 0.5-1.5%, more preferably 0.6-1.4%, and even more preferably 0.8-1.2%.

[0026] In this invention, pectin and sodium alginate are added to water and stirred until completely dissolved to obtain a solution. The stirring temperature is preferably 30~50℃, more preferably 35~45℃, and even more preferably 38~42℃.

[0027] In this invention, the mass concentration of the calcium chloride solution is preferably 0.1-1%, more preferably 0.2-0.8%, and even more preferably 0.4-0.6%.

[0028] In this invention, the volume ratio of pectin-sodium alginate solution to calcium chloride solution is preferably 8~12:1, more preferably 9~11:1, and even more preferably 9.5~10:1; calcium chloride solution is added dropwise to pectin-sodium alginate solution.

[0029] In this invention, the crosslinking time in step (1) is preferably ≥30 min, more preferably ≥40 min, and even more preferably ≥50 min; stirring is maintained during the crosslinking process.

[0030] In this invention, the mass ratio of perfluorohexanone to wall material emulsion in step (2) is preferably 1:4~6, more preferably 1:4.5~5.5, and even more preferably 1:4.8~5.2; perfluorohexanone is added dropwise to the emulsion.

[0031] In this invention, the mixing temperature in step (2) is preferably 35~45℃, more preferably 36~44℃, and even more preferably 38~42℃; the mixing time is preferably ≥60min, more preferably ≥90min, and even more preferably ≥120min; the mixing speed is preferably ≥1500rpm, more preferably ≥2000rpm, and even more preferably ≥2500rpm.

[0032] In this invention, the chitosan emulsion in step (3) comprises chitosan, emulsifier, water and acetic acid solution.

[0033] In this invention, the mass ratio of chitosan, emulsifier and water is preferably 8~12:2~4:100, more preferably 9~11:2.5~3.5:100, and even more preferably 9.5~10.5:2.8~3.2:100.

[0034] In this invention, the emulsifier is Tween 80.

[0035] In this invention, the concentration of the acetic acid solution is preferably 2-4%, more preferably 2.5-3.5%, and even more preferably 2.8-3.2%; the pH of the chitosan emulsion is preferably 2-4, more preferably 2.5-3.5, and even more preferably 2.8-3.2.

[0036] In this invention, chitosan is added to water, and then acetic acid solution is added dropwise to adjust the pH. The mixture is stirred until the chitosan is completely dissolved. The stirring temperature is preferably 30~50℃, more preferably 35~45℃, and even more preferably 38~42℃. Finally, an emulsifier is added for activation. The activation stirring time is preferably ≥30min, more preferably ≥35min, and even more preferably ≥40min. After activation, a chitosan emulsion is obtained.

[0037] In this invention, the volume ratio of the inner layer emulsion to the chitosan emulsion in step (3) is preferably 1:3~4, more preferably 1:3.2~3.8, and even more preferably 1:3.4~3.6; the inner layer emulsion is added dropwise to the chitosan emulsion.

[0038] In this invention, the mixing temperature in step (3) is preferably 45~55℃, more preferably 46~54℃, and even more preferably 48~52℃, and the time is preferably ≥60min, more preferably ≥70min, and even more preferably ≥80min.

[0039] In this invention, the mass concentration of the glutaraldehyde solution in step (4) is preferably 10-30%, more preferably 15-25%, and even more preferably 18-22%.

[0040] In this invention, the volume ratio of the double-layer wall material emulsion to the glutaraldehyde solution in step (4) is preferably 80~100:1, more preferably 85~95:1, and even more preferably 88~90:1; the glutaraldehyde solution is added dropwise to the double-layer wall material emulsion.

[0041] In this invention, the mixing temperature in step (4) is preferably 45~55℃, more preferably 46~54℃, and even more preferably 48~52℃, and the time is preferably ≥3h, more preferably ≥3.5h, and even more preferably ≥4h; during the mixing process, the pH of the system is adjusted to neutral using sodium hydroxide solution.

[0042] In this invention, after mixing, the mixture is precipitated and filtered, washed with deionized water, and dried at low temperature to obtain microcapsules.

[0043] In this invention, the concentration of the saponin solution in step (5) is preferably 0.03~0.15%, more preferably 0.05~0.1%, and even more preferably 0.07~0.08%.

[0044] In this invention, the mass of the microcapsules in step (5) is preferably 3-5% of the mass of the saponin solution, more preferably 3.5-4.5%, and even more preferably 3.8-4.2%.

[0045] The flowchart of the preparation method of the adaptive microcapsule system of the present invention is shown below. Figure 1 As shown.

[0046] The present invention also provides a method for preparing the adaptive microcapsule system to obtain the adaptive microcapsule system.

[0047] The present invention also provides the application of the adaptive microcapsule system in coal seam mining.

[0048] This invention also provides an in-situ dust suppression method for coal seam mining dust, comprising the following steps: (a) Drill holes are arranged in the intake airway and return airway, and injection lines are installed in the drill holes. The injection lines are connected to the sealing device in a closed manner. (b) Inject the adaptive microcapsule system into the original coal seam before coal release; (c) The adaptive microcapsule system naturally descends during coal discharge, and the saponin solution increases the temperature difference between coal and coal gangue, thus identifying coal gangue; (d) After coal is released, the microcapsules adhere to the surface of the remaining coal and fall into the goaf together to prevent spontaneous combustion.

[0049] In this invention, the distance between two adjacent boreholes in step (a) is preferably 10-15m, more preferably 11-14m, and even more preferably 12-13m; the borehole depth is preferably 50-150m, more preferably 60-140m, and even more preferably 80-120m.

[0050] In this invention, the grouting pressure injected in step (b) is preferably 3~5 MPa, more preferably 3.5~4.5 MPa, and even more preferably 3.8~4.2 MPa.

[0051] A schematic diagram of the coal seam mining construction method of this invention is shown below. Figure 2 As shown, Figure 2 In the diagram, 1 is the sealing material, 2 is the drilling hole, 3 is the connector, 4 is the sealing device, 5 is the injection pipeline, 6 is the high-pressure hose, 7 is the regulating valve, 8 is the pressure gauge, 9 is the water injection equipment, and 10 is the adaptive microcapsule system.

[0052] A schematic diagram of the adaptive microcapsule system synergistic processing during the coal discharge process of this invention is shown below. Figure 3 As shown, Figure 3 In the diagram, 1 is an infrared thermal imager, 2 is a nozzle, 3 is a scraper conveyor, 4 is gangue, 5 is residual coal in the goaf, 6 is a hydraulic support, 7 is a coal mining machine, 8 is top coal, and 9 is a mixed solution.

[0053] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0054] Example 1

[0055] Pectin and sodium alginate were added to water at a mass ratio of 3:1, with the pectin concentration controlled at 1%. The mixture was stirred at 40°C until completely dissolved to obtain a pectin-sodium alginate solution. A 0.5% calcium chloride solution was added dropwise to the pectin-sodium alginate solution, with the volume ratio of the pectin-sodium alginate solution to the calcium chloride solution controlled at 10:1. The mixture was stirred for 30 minutes to crosslink and obtain a wall material emulsion. Perfluorohexanone was added dropwise to the above emulsion, with the mass ratio controlled at 1:5. The mixture was stirred at 40°C and 1500 rpm for 60 minutes to obtain an inner layer emulsion.

[0056] The mass ratio of chitosan, emulsifier and water was controlled at 10:3:100. Chitosan powder was added to water, and 3% acetic acid solution was added dropwise to adjust the pH to 3. The mixture was stirred at 40°C until the chitosan was completely dissolved. Finally, Tween 80 was added to activate the mixture for 30 minutes to obtain a chitosan emulsion.

[0057] The inner layer emulsion and chitosan emulsion were added dropwise to the chitosan emulsion at a ratio of 1:3.5, and mixed at 50°C for 60 min to obtain a double-layer wall material emulsion. A 20% glutaraldehyde solution was added dropwise to the above double-layer wall material emulsion at a mass ratio of 1:90, and mixed at 50°C for 3 h. During the mixing process, the pH was adjusted to neutral with sodium hydroxide solution. After mixing, the precipitate was filtered, washed with deionized water, and dried at low temperature to obtain microcapsules.

[0058] Add 4% microcapsules to a 0.1% saponin solution and mix thoroughly to obtain an adaptive microcapsule system.

[0059] After the working face roadway excavation is completed, select appropriate drilling equipment to lay holes every 13m in the intake and return airways, with a drilling depth of 100m. Install injection pipelines into the holes, connect them to the sealing device, and check the sealing and reliability of the pipeline connection.

[0060] The grouting pressure was set to 4 MPa, and the adaptive microcapsule system was injected into the pores and fractures of the original coal seam through a water injection device.

[0061] In the coal discharge process, the outer wall material of the microcapsule is chitosan, which adsorbs dust particles. A low-temperature saponin solution is sprayed onto the coal discharge area. With the help of infrared image recognition technology, the saponin solution increases the temperature difference between coal and gangue, thereby improving the accuracy of coal and gangue identification.

[0062] After the coal release operation is completed, the microcapsules adhere to the surface and fall into the goaf along with the remaining coal. When the ambient temperature in the goaf rises to the threshold, perfluorohexanone is heated and breaks through the wall material to diffuse in the goaf, reducing the oxygen concentration and blocking the spontaneous combustion chain reaction, thus preventing spontaneous combustion of the remaining coal in the goaf.

[0063] When used in conjunction with a saponin solution, the adaptive microcapsules provided by this invention can achieve a dust suppression rate of over 90% during coal discharge; a coal gangue identification accuracy of over 95%; and a flame-retardant response time of residual coal in goaf areas of less than 10 seconds, thereby improving overall treatment efficiency by over 30%.

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for the preparation of an adaptive microcapsule system, characterized in that, Includes the following steps: (1) A wall material emulsion is obtained by mixing and crosslinking pectin-sodium alginate solution and calcium chloride solution; (2) The inner layer emulsion is obtained by mixing perfluorohexanone and the wall material emulsion; (3) Mix the inner layer emulsion and the chitosan emulsion to obtain a double-layer wall material emulsion; (4) Mix the double-layer wall material emulsion and glutaraldehyde solution to obtain microcapsules; (5) Mix the microcapsules and saponin solution to obtain the adaptive microcapsule system.

2. The method for preparing the adaptive microcapsule system as described in claim 1, characterized in that, In step (1), the mass ratio of pectin to sodium alginate is 2-4:1; The pectin concentration in the pectin-sodium alginate solution is 0.5%~1.5% by mass. The mass concentration of the calcium chloride solution is 0.1%~1%; The volume ratio of pectin-sodium alginate solution to calcium chloride solution is 8~12:1; The crosslinking time in step (1) is ≥30 min; In step (2), the mass ratio of perfluorohexanone to wall material emulsion is 1:4~6; In step (2), the mixing temperature is 35~45℃, the time is ≥60min, and the rotation speed is ≥1500rpm.

3. The method for preparing the adaptive microcapsule system as described in claim 2, characterized in that, In step (3), the chitosan emulsion contains chitosan, emulsifier, water, and acetic acid solution; The mass ratio of chitosan, emulsifier and water is 8~12:2~4:100; The concentration of the acetic acid solution is 2-4%; the pH of the chitosan emulsion is 2-4. In step (3), the volume ratio of the inner emulsion to the chitosan emulsion is 1:3~4; In step (3), the mixing temperature is 45~55℃ and the time is ≥60min.

4. The method for preparing the adaptive microcapsule system as described in claim 3, characterized in that, In step (4), the mass concentration of the glutaraldehyde solution is 10-30%. In step (4), the volume ratio of the double-layer wall material emulsion to the glutaraldehyde solution is 80~100:1; In step (4), the mixing temperature is 45~55℃ and the time is ≥3h.

5. The method for preparing the adaptive microcapsule system as described in claim 4, characterized in that, In step (5), the concentration of the saponin solution is 0.03~0.15%; In step (5), the mass of the microcapsules is 3-5% of the mass of the saponin solution.

6. The adaptive microcapsule system prepared by the method of any one of claims 1 to 5.

7. The application of the adaptive microcapsule system of claim 6 in coal seam mining.

8. An in-situ dust suppression method for coal seam mining dust, characterized in that, Includes the following steps: (a) Drill holes are arranged in the intake airway and return airway, and injection lines are installed in the drill holes. The injection lines are connected to the sealing device in a closed manner. (b) Injecting the adaptive microcapsule system of claim 6 into the original coal seam before coal release; (c) The adaptive microcapsule system naturally descends during coal discharge, and the saponin solution increases the temperature difference between coal and coal gangue, thus identifying coal gangue; (d) After coal is released, the microcapsules adhere to the surface of the remaining coal and fall into the goaf together to prevent spontaneous combustion.

9. The in-situ dust suppression method for coal seam mining dust as described in claim 8, characterized in that, In step (a), the distance between two adjacent boreholes is 10-15m, and the borehole depth is 50-150m.

10. The in-situ dust suppression method for coal seam mining dust as described in claim 9, characterized in that, The grouting pressure injected in step (b) is 3~5MPa.

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