A modified fiber mining filling material and its preparation method

Abstract

The present invention provides a modified fiber mining filling material and its preparation method. Through the dual modification technology of plasma treatment and silane coupling agent, the uniform dispersion of fibers in the binder is enhanced, and the properties such as rapid setting, early strength and compressive strength retention rate of the filling material are significantly improved. The filling material includes raw materials such as clinker, solid waste, retarder, early strength agent, modified fiber, accelerator, gypsum, water reducing agent and suspending agent. Among them, the modified fiber is treated through specific steps, increasing the surface functional groups and improving the compatibility and adhesion with the binder. The filling material of the present invention has good transportability, is easy to construct, has low cost, and has environmental protection characteristics, meeting the development trend of green mining. It is particularly suitable for applications in mine filling support, and has broad application prospects and social and economic value.

Description

Technical Field

[0001] The present invention belongs to the field of mining filling materials, and in particular relates to a modified fiber mining filling material and a preparation method thereof. Background Art

[0002] From the perspective of mine filling mining technology and application, the requirements for filling materials are as follows: the initial setting time is adjustable, the final setting time needs to be short, the material can flow by itself or be pumped, and the filling body has high strength in the later stage. Commonly used filling materials include fly ash, gypsum, lime, cement, coal gangue, slag and other materials. Traditional filling mines mainly increase the strength of the filling body by increasing the content of cementitious materials in the filling slurry, but this will increase the filling cost. At the same time, the excessive amount of cementitious materials will cause the filling body to increase brittleness, sudden damage and instability. Problems are prominent. Furthermore, the large-scale use of cement, slag and other materials as mining filling materials will increase the density of the material, thereby increasing the amount of auxiliary transportation, which is not conducive to the transportation of materials.

[0003] Fiber-bonded filling technology has been widely used in the field of mining filling due to its unique advantages. By combining fiber materials with binders, the overall mechanical properties of the material, including compressive strength and impact resistance, can be significantly improved. The addition of fibers can effectively disperse stress and reduce stress concentration within the material, thereby improving the durability and reliability of the structure. Fiber-bonded filling materials have good crack control capabilities. When the structure is subjected to loads, the presence of fibers can delay the expansion of cracks and increase the toughness of the material, making the structure exhibit better stability and safety when subjected to impact or cyclic loads. Compared with traditional reinforcement methods, fiber-bonded filling technology can not only reduce the amount of materials used and reduce project costs, but also simplify the construction process, shorten the construction period, and improve project efficiency. With the increasing requirements for sustainable development and environmental protection, fiber-bonded filling technology has received increasing attention due to its lower environmental impact and resource consumption.

[0004] However, fiber-bonded filling technology encounters the problem of poor dispersion during mine filling applications. This is mainly due to the difficulty in achieving uniform distribution of fiber materials in the binder. When the fiber and binder are not mixed evenly, the mechanical properties and durability of the material will be affected, resulting in a decrease in the stability and reliability of the overall structure. Poor dispersion causes the fibers to form aggregated areas in the material, causing stress concentration and increasing the risk of material damage when subjected to stress. At the same time, the aggregation of fibers may also lead to an increase in the porosity within the material, reducing the material's density and impermeability. Therefore, improving the dispersion of fibers in the binder is key to ensuring the successful application of fiber-bonded filling technology.

[0005] To improve the dispersion of fibers, some technical means can be adopted, such as using a blender for sufficient mixing, or adopting special mixing processes and equipment to ensure the uniform distribution of fibers in the binder. At the same time, selecting appropriate fiber lengths and types, as well as optimizing the ratio and properties of the binder, are also effective methods to improve dispersion. Through these measures, the overall performance and application effect of the fiber-cement filling material can be significantly improved.

[0006] Aiming at the problem of uneven dispersion of fiber materials in the binder, the present invention provides a method for modifying fibers. The fibers are etched on the surface by an acidic solution, and at the same time, ultrasonic oscillation is used to make the molecular chains in the fibers relax and creep. Then, the fibers are treated with plasma and silane coupling agent, increasing functional groups such as carboxyl and hydroxyl groups on the fiber surface, which is beneficial to the uniform distribution of fibers in the binder, improving the compressive strength and compressive strength retention rate after filling, and thus enhancing the durability and reliability of the structure. Summary of the Invention

[0007] Aiming at the problems existing in the prior art, the present invention provides a modified fiber mine filling material and its preparation method. By using the dual modification technology of plasma treatment and silane coupling agent, it promotes the uniform dispersion of fibers in the binder, making the filling material have excellent properties such as better quick setting, early strength, and high compressive strength retention rate, and is particularly suitable for applications in mine filling and support.

[0008] A modified fiber mine filling material involved in the present invention, in parts by weight, comprises the following raw material components: 35 - 75 parts of cement clinker, 10 - 20 parts of solid waste, 0.1 - 3 parts of retarder, 1 - 5 parts of early strength agent, 20 - 45 parts of modified fiber, 5 - 15 parts of quick setting agent, 10 - 20 parts of gypsum, 0.1 - 3 parts of water reducing agent, and 0.5 - 5 parts of suspending agent.

[0009] The cement clinker includes at least one of aluminate cement clinker, sulphoaluminate cement clinker, ferroaluminate cement clinker, and fluoroaluminate cement clinker.

[0010] The solid waste includes at least one of steel slag powder, copper slag powder, fly ash, carbide slag, and coal gangue.

[0011] The retarder includes at least one of sodium gluconate, borax, or citric acid.

[0012] The early strength agent includes at least one of calcium chloride, calcium sulfate, water glass, or triethanolamine.

[0013] The quick setting agent includes at least one of sodium metaaluminate, sodium sulfate, or sodium carbonate.

[0014] The gypsum includes at least one of raw gypsum, desulfurized gypsum, phosphogypsum, and fluorogypsum.

[0015] The suspending agent includes at least one of sodium carboxymethyl cellulose, water-soluble polyvinyl alcohol or hydroxypropyl methylcellulose.

[0016] The water reducing agent includes at least one of naphthalene water reducing agent, melamine water reducing agent or polycarboxylate water reducing agent.

[0017] The preparation method of the modified fiber is as follows:

[0018] S1: Wash the fiber and dry it at 90 - 120°C for 2 - 5 h;

[0019] S2: Place the fiber obtained in step S1 in an acidic solution at a temperature of 40 - 90°C, immerse it and ultrasonically vibrate for 30 - 60 minutes;

[0020] S3: Filter out the fiber in step S2, dry it, and treat it with plasma for 2 - 10 min;

[0021] S4: Place the fiber in step S3 in a solution containing a silane coupling agent and soak it for 10 - 30 minutes, wash, filter, and dry to obtain the required modified fiber.

[0022] The fiber includes at least one of glass fiber, polyester fiber, polyamide fiber, polyvinyl alcohol fiber, polyacrylonitrile fiber, polypropylene fiber, polyvinyl chloride fiber, aluminum silicate fiber, basalt fiber, and the length of the fiber is 1 - 30 mm.

[0023] The acidic solution is at least one of dilute hydrochloric acid, dilute sulfuric acid, acetic acid, formic acid, propionic acid, organic boric acid, organic phosphoric acid; the concentration of the acidic solution is not specifically required as long as the surface of the fiber can be etched.

[0024] The silane coupling agent includes at least one of γ-aminopropyltriethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and the concentration of the silane coupling agent solution is preferably 5 - 40%.

[0025] Plasma treatment is a commonly used method for surface modification and is applicable to various reinforcing materials. It can generate free radicals, ions and metastable substances on the surface of the reinforcing material, causing cross-linking and oxidation reactions. The surface modification effect of plasma treatment is significant. For example, oxygen plasma treatment can generate functional groups such as -COOH and C-OH on the fiber surface, while improving the wettability of the fiber, and the surface roughness also increases significantly. The oxygen plasma, nitrogen plasma, etc. commonly used in the art can be used to achieve the purpose of the present invention.

[0026] The surface of the fiber is etched by an acidic solution, and at the same time, ultrasonic oscillation is used to make the molecular chains in the fiber relax and wriggle, generating pores. The acidic solution can enter the pores to further etch the fiber surface and partially remain on the fiber surface. In this way, the roughness and specific surface area of the fiber surface are greatly increased. Therefore, it is more conducive to the interaction between the silane coupling agent, plasma and the fiber. At the same time, because some polar bonds remain on the fiber, it is also conducive to the uniform distribution of the fiber in the binder, improving the compressive strength after filling, reducing the stress concentration inside the material, and thus improving the durability and reliability of the structure.

[0027] The present invention also provides a preparation method of a modified fiber mining filling material, comprising the following steps:

[0028] Mix 35 - 75 parts of cement clinker, 10 - 20 parts of solid waste, 0.1 - 3 parts of retarder, 1 - 5 parts of early strength agent, 20 - 45 parts of modified fiber, 5 - 15 parts of accelerator, 10 - 20 parts of gypsum, 0.1 - 3 parts of water reducing agent, and 0.5 - 5 parts of suspending agent evenly, and add 100 - 600 parts of water and stir to mix, then the modified fiber mining filling material is obtained.

[0029] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0030] 1) The present invention utilizes the characteristics of cement clinker with early strength and rapid hardening, and at the same time, by adding water reducing agent, early strength agent, retarder, etc., to ensure its fluidity, having good fluidity within 30 minutes to meet the pouring requirements; it can quickly set and harden between 100 - 180 minutes, making the filling material have better properties such as quick setting and early strength.

[0031] 2) The present invention significantly improves the dispersion of fibers in the filling material by adopting the dual modification technologies of plasma treatment and silane coupling agent. Plasma treatment can effectively change the properties of the fiber surface and increase its surface energy, while the silane coupling agent acts as a bridging agent to further promote the compatibility and adhesion between the fiber and the binder. This synergistic effect effectively avoids fiber aggregation, thereby reducing stress concentration and improving the uniformity and integrity of the material. Through this modification, the filling material exhibits higher compressive strength, and even when affected by the external environment, such as being immersed in water for a long time, it can still maintain a high strength, that is, it has an excellent compressive strength retention rate. This not only enhances the stability and durability of the filling body, but also is of great significance for improving the reliability and safety of mine support. In addition, the addition of modified fibers may also improve other properties of the filling material, such as crack resistance, toughness and overall mechanical properties, making it more adaptable to complex mine environments and engineering requirements.

[0032] 3) In the cement clinker system, the introduction of gypsum not only significantly improves the early compressive strength of the composite cementing material but also ensures the long-term strength retention rate, which is crucial for ensuring the long-term stability of the filling body. In addition, the incorporation of gypsum helps to regulate the setting time of the cement clinker, ensuring the feasibility of construction operations and the timely hardening of the filling material.

[0033] 4) The preparation method of the modified fiber mining filling material of the present invention is simple and low-cost. It only needs to simply stir and mix them at the application site to quickly obtain the required filling material. This method not only simplifies the on-site operation process but also significantly reduces the preparation cost. In addition, the mixed filling material has good transportability and can be transported over long distances, greatly improving the engineering efficiency. At the same time, the environmental protection characteristics of this material also conform to the current development trend of green mining, and it has broad application prospects and important social and economic value. Specific embodiments

[0034] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] Embodiment 1

[0036] This embodiment provides a modified fiber mining filling material with the following formula: 50 parts of cement clinker, 10 parts of solid waste, 1 part of retarder, 2 parts of early strength agent, 25 parts of modified fiber, 10 parts of accelerator, 15 parts of gypsum, 1 part of water reducer, and 2 parts of suspending agent.

[0037] The cement clinker used in this embodiment is aluminate cement clinker, the solid waste is steel slag powder, the retarder is sodium gluconate, the early strength agent is calcium sulfate, the accelerator is sodium sulfate, the gypsum is desulfurized gypsum, the suspending agent is sodium carboxymethylcellulose, and the water reducer is a polycarboxylate-based water reducer.

[0038] The preparation method of the modified fiber is as follows:

[0039] S1: Take 25 g of polypropylene fibers with a length of 10 mm and place them in 300 mL of absolute ethanol, ultrasonically clean for 15 min, and then dry at 100 °C for 3 h;

[0040] S2: Place the polypropylene fibers obtained in step S1 in a dilute hydrochloric acid solution at a temperature of 50 °C, immerse and ultrasonically vibrate for 60 minutes;

[0041] S3: Filter out the fibers in step S2, dry them at 105 °C, and treat them with oxygen plasma for 5 min;

[0042] S4: Immerse the fibers from step S3 in an ethanol solution of γ-aminopropyltriethoxysilane with a mass concentration of 30% for 20 minutes, wash and filter, and dry at 80 °C for 2 h to obtain the required modified polypropylene fibers.

[0043] The preparation method of the modified fiber mine filling material in this embodiment includes the following steps:

[0044] Weigh 50 parts of cement clinker, 10 parts of solid waste, 1 part of retarder, 2 parts of early strength agent, 25 parts of modified fiber, 10 parts of accelerator, 15 parts of gypsum, 1 part of water reducer, and 2 parts of suspending agent. After mixing evenly, add 200 parts of water and stir to mix evenly to obtain the modified fiber mine filling material.

[0045] Example 2

[0046] This embodiment provides a modified fiber mine filling material with the following formulation: 70 parts of cement clinker, 15 parts of solid waste, 2 parts of retarder, 1 part of early strength agent, 35 parts of modified fiber, 5 parts of accelerator, 20 parts of gypsum, 0.5 part of water reducer, and 3 parts of suspending agent.

[0047] The cement clinker used in this embodiment is a combination of sulphoaluminate cement clinker and ferroaluminate cement clinker in a ratio of 1:1. The solid waste is a mixture of fly ash and carbide slag in a ratio of 1:2. The retarder is borax. The early strength agent is a combination of calcium chloride and triethanolamine in a ratio of 1:1. The accelerator is sodium carbonate. The gypsum is raw gypsum. The suspending agent is water-soluble polyvinyl alcohol. The water reducer is a naphthalene-based water reducer.

[0048] The preparation method of the modified fiber is as follows:

[0049] S1: Take 15 g of aluminosilicate fibers with a length of 20 mm and place them in 200 mL of anhydrous ethanol. Ultrasonically clean for 15 min, and then dry at 100 °C for 3 h;

[0050] S2: Place the aluminosilicate fibers obtained in step S1 in an acetic acid solution at a temperature of 30 °C, immerse and ultrasonically vibrate for 50 minutes;

[0051] S3: Filter out the fibers from step S2, dry at 105 °C, and treat with nitrogen plasma for 8 min;

[0052] S4: Immerse the fibers from step S3 in an ethanol solution of vinyltriethoxysilane with a mass concentration of 30% for 30 minutes, wash and filter, and dry at 100 °C for 1 h to obtain the required modified aluminosilicate fibers.

[0053] The preparation method of the modified fiber mine filling material in this embodiment includes the following steps:

[0054] Weigh 70 parts of cement clinker, 15 parts of solid waste, 2 parts of retarder, 1 part of early strength agent, 35 parts of modified fiber, 5 parts of accelerating agent, 20 parts of gypsum, 0.5 part of water reducing agent, and 3 parts of suspending agent. After mixing evenly, add 300 parts of water and stir to mix evenly to obtain the modified fiber mine filling material.

[0055] Example 3

[0056] This example provides a modified fiber mine filling material, and the formula is: 35 parts of cement clinker, 20 parts of solid waste, 3 parts of retarder, 4 parts of early strength agent, 45 parts of modified fiber, 15 parts of accelerating agent, 15 parts of gypsum, 2 parts of water reducing agent, and 4 parts of suspending agent.

[0057] The cement clinker used in this example is a combination of calcium ferrite aluminate cement clinker and calcium fluoroaluminate cement clinker in a ratio of 2:1. The solid waste is a mixture of carbide slag and coal gangue in a ratio of 1:1. The retarder is a combination of borax and citric acid in a ratio of 2:1. The early strength agent is a combination of water glass and triethanolamine in a ratio of 1:1. The accelerating agent is sodium metaaluminate. The gypsum is a combination of phosphogypsum and fluorogypsum in a ratio of 3:1. The suspending agent is hydroxypropyl methylcellulose, and the water reducing agent is melamine water reducing agent.

[0058] The preparation method of the modified fiber is as follows:

[0059] S1: Place 10 g of glass fibers with a length of 15 mm in 200 mL of absolute ethanol, ultrasonically clean for 15 min, and then dry at 110 °C for 2 h;

[0060] S2: Place the glass fibers obtained in step S1 in an organic boric acid solution at a temperature of 40 °C, immerse and ultrasonically vibrate for 40 minutes;

[0061] S3: Filter out the fibers in step S2, dry at 115 °C, and treat with oxygen plasma for 6 min;

[0062] S4: Place the fibers in step S3 in an ethanol solution of γ-glycidoxypropyltrimethoxysilane with a mass concentration of 15% and immerse for 35 minutes, wash and filter, and dry at 110 °C for 1 h to obtain the required modified glass fibers.

[0063] The preparation method of the modified fiber mine filling material in this example includes the following steps:

[0064] Weigh 35 parts of cement clinker, 20 parts of solid waste, 3 parts of retarder, 4 parts of early strength agent, 45 parts of modified fiber, 15 parts of accelerating agent, 15 parts of gypsum, 2 parts of water reducing agent, and 4 parts of suspending agent. After mixing evenly, add 350 parts of water and stir to mix evenly to obtain the modified fiber mine filling material.

[0065] Example 4

[0066] This embodiment provides a modified fiber mining filling material, the formula of which is: 65 parts of cement clinker, 15 parts of solid waste, 0.5 parts of retarder, 1 part of early strength agent, 25 parts of modified fiber, 5 parts of accelerating agent, 20 parts of gypsum, 3 parts of water reducing agent, and 5 parts of suspending agent.

[0067] The cement clinker used in this embodiment is a mixture of aluminate cement clinker and fluoroaluminate cement clinker in a ratio of 3:1, the solid waste is a mixture of copper slag powder and fly ash in a ratio of 2:1, the retarder is borax, the early strength agent is triethanolamine, the quick-setting agent is sodium carbonate, the gypsum is a mixture of phosphogypsum and desulfurized gypsum in a ratio of 2:1, the suspending agent is hydroxypropyl methylcellulose, and the water reducer is a polycarboxylate water reducer.

[0068] The preparation method of the modified fiber is as follows:

[0069] S1: 10 g of 5 mm long polyamide fiber was placed in 200 mL of anhydrous ethanol, ultrasonically cleaned for 25 min, and then dried at 90 °C for 3 h;

[0070] S2: placing the polyamide fiber obtained in step S1 in an organic phosphoric acid solution at a temperature of 40° C., immersing and ultrasonically vibrating for 30 minutes;

[0071] S3: Filter out the fibers from step S2, dry them at 100°C, and treat them with oxygen plasma for 6 minutes;

[0072] S4: Immerse the fiber obtained in step S3 in an ethanol solution containing 10% γ-methacryloxypropyltrimethoxysilane by mass for 30 minutes, wash and filter, and dry at 110° C. for 1 hour to obtain the desired modified polyamide fiber.

[0073] The method for preparing the modified fiber mining filling material of this embodiment comprises the following steps:

[0074] Weigh 65 parts of cement clinker, 15 parts of solid waste, 0.5 parts of retarder, 1 part of early strength agent, 25 parts of modified fiber, 5 parts of quick-setting agent, 20 parts of gypsum, 3 parts of water reducer, and 5 parts of suspending agent, mix them evenly, add 300 parts of water, stir and mix evenly, and obtain a modified fiber mining filling material.

[0075] Example 5

[0076] This embodiment provides a modified fiber mining filling material, the formula of which is: 55 parts of cement clinker, 20 parts of solid waste, 1 part of retarder, 2 parts of early strength agent, 35 parts of modified fiber, 10 parts of accelerating agent, 20 parts of gypsum, 2 parts of water reducing agent, and 4 parts of suspending agent.

[0077] The Portland cement clinker used in this embodiment is fluoroaluminate Portland cement clinker, the solid waste is fly ash, the retarder is borax, the early strength agent is calcium sulfate, the accelerating agent is sodium carbonate, the gypsum is phosphogypsum and raw gypsum in a 2:1 combination, the suspending agent is hydroxypropyl methylcellulose, and the water reducing agent is polycarboxylate water reducing agent.

[0078] The preparation method of the modified fiber is as follows:

[0079] S1: Place 15 g of polyvinyl alcohol fibers with a length of 10 mm in 200 mL of absolute ethanol, ultrasonically clean for 25 min, and then dry at 90 °C for 3 h;

[0080] S2: Place the polyvinyl alcohol fibers obtained in step S1 in a dilute sulfuric acid solution at 40 °C, immerse and ultrasonically vibrate for 35 minutes;

[0081] S3: Filter out the fibers in step S2, dry at 100 °C, and treat with oxygen plasma for 5 min;

[0082] S4: Place the fibers in step S3 in an ethanol solution with a mass concentration of 35% vinyltriethoxysilane and immerse for 30 minutes, wash and filter, and dry at 100 °C for 2 h to obtain the required modified polyvinyl alcohol fibers.

[0083] The preparation method of the modified fiber mine filling material in this embodiment includes the following steps:

[0084] Weigh 55 parts of Portland cement clinker, 20 parts of solid waste, 1 part of retarder, 2 parts of early strength agent, 35 parts of modified fiber, 10 parts of accelerating agent, 20 parts of gypsum, 2 parts of water reducing agent, and 4 parts of suspending agent, mix them evenly in advance, and add 400 parts of water and stir to mix evenly to obtain the modified fiber mine filling material.

[0085] Example 6

[0086] This embodiment provides a modified fiber mine filling material, and the formula is: 65 parts of Portland cement clinker, 20 parts of solid waste, 0.1 part of retarder, 1 part of early strength agent, 30 parts of modified fiber, 5 parts of accelerating agent, 20 parts of gypsum, 3 parts of water reducing agent, and 5 parts of suspending agent.

[0087] The Portland cement clinker used in this embodiment is ferroaluminate Portland cement clinker, the solid waste is coal gangue, the retarder is borax, the early strength agent is calcium chloride, the accelerating agent is sodium sulfate, the gypsum is desulfurized gypsum and raw gypsum in a 1:1 combination, the suspending agent is hydroxypropyl methylcellulose, and the water reducing agent is polycarboxylate water reducing agent.

[0088] The preparation method of the modified fiber is as follows:

[0089] S1: Place 20 g of polyvinyl chloride fibers with a length of 15 mm in 200 mL of absolute ethanol, ultrasonically clean for 25 min, and then dry at 100 °C for 2 h;

[0090] S2: Place the polyvinyl chloride fibers obtained in step S1 in an acetic acid solution at 40 °C, immerse and ultrasonically vibrate for 30 minutes;

[0091] S3: Filter out the polyvinyl chloride fibers in step S2, dry at 100 °C, and treat with oxygen plasma for 5 min;

[0092] S4: Place the polyvinyl chloride fibers in step S3 in an ethanol solution of γ-aminopropyltriethoxysilane with a mass concentration of 10% and immerse for 30 minutes, wash and filter, and dry at 100 °C for 2 h to obtain the required modified polyvinyl chloride fibers.

[0093] The preparation method of the modified fiber mine filling material in this example includes the following steps:

[0094] Weigh 65 parts of cement clinker, 20 parts of solid waste, 0.1 part of retarder, 1 part of early strength agent, 30 parts of modified fiber, 5 parts of accelerator, 20 parts of gypsum, 3 parts of water reducer, and 5 parts of suspending agent, mix them evenly in advance, and then add 300 parts of water and stir to mix evenly to obtain the modified fiber mine filling material.

[0095] Example 7

[0096] Use basalt fibers to replace the polypropylene fibers in Example 1, and other conditions are the same as those in Example 1.

[0097] Example 8

[0098] Use polyacrylonitrile fibers to replace the polypropylene fibers in Example 1, and other conditions are the same as those in Example 1.

[0099] Example 9

[0100] Use polyester fibers to replace the polypropylene fibers in Example 1, and other conditions are the same as those in Example 1.

[0101] Example 10

[0102] The length of the polypropylene fibers is 1 mm, and other conditions are the same as those in Example 1.

[0103] Example 11

[0104] The length of the polypropylene fibers is 5 mm, and other conditions are the same as those in Example 1.

[0105] Example 12

[0106] The length of the polypropylene fibers is 15 mm, and other conditions are the same as those in Example 1.

[0107] Example 13

[0108] The length of the polypropylene fiber is 20 mm, and other conditions are the same as those in Example 1.

[0109] Example 14

[0110] The length of the polypropylene fiber is 25 mm, and other conditions are the same as those in Example 1.

[0111] Example 15

[0112] The length of the polypropylene fiber is 30 mm, and other conditions are the same as those in Example 1.

[0113] Comparative Example 1

[0114] The difference from Example 1 is that no modified polypropylene fiber is added, and an equal amount of cement clinker is used to replace the modified polypropylene fiber, and other conditions are the same as those in Example 1.

[0115] Comparative Example 2

[0116] The difference from Example 1 is that the polypropylene fiber is not modified, that is, unmodified polypropylene fiber is used to replace the modified polypropylene fiber, and other conditions are the same as those in Example 1.

[0117] Comparative Example 3

[0118] The difference from Example 1 is that the step of impregnating with S2 acidic solution is omitted, and other conditions are the same as those in Example 1.

[0119] Comparative Example 4

[0120] The difference from Example 1 is that the step of S3 plasma treatment is omitted, and after impregnating with the acidic solution, it is directly modified with a silane coupling agent, and other conditions are the same as those in Example 1.

[0121] Comparative Example 5

[0122] The difference from Example 1 is that the step of S4 silane coupling agent treatment is omitted, and after impregnating with the acidic solution, the modified polypropylene fiber is obtained after plasma treatment, and other conditions are the same as those in Example 1.

[0123] Comparative Example 6

[0124] The difference from Example 1 is that no gypsum is added, and an equal amount of cement clinker is used to replace the gypsum, and other conditions are the same as those in Example 1.

[0125] The properties of the modified fiber mine filling materials prepared in this example and the comparative example are shown in Table 1. Among them, the well-stirred slurry is injected into a triple mold of 40mm×40mm×160mm. After curing at room temperature of 25°C for 48h, the material is demolded and cut. After the material is dried, the compressive strength, longitudinal expansion rate and other properties of the material are tested. Among them, the initial setting time and final setting time of the material are tested in accordance with the "Standard Test Method for Properties of Ordinary Concrete Mixtures" (GB / T50080-2016); the compressive strength is detected by "JC / T984-2011"; the vertical expansion rate refers to Appendix C of GB 50119-2003.

[0126] Retention rate of compressive strength: Take the test piece to test the compressive strength, denoted as M1. After that, soak the test piece in water for 72h and then test the compressive strength, denoted as M2. The retention rate of compressive strength = M2 / M1 * 100.

[0127] Table 1 Properties of filling materials in different examples and control examples

[0128]

[0129] It can be seen from the performance test in Table 1 that the modified fiber mine filling material prepared in the embodiment of the present invention has good fluidity within 30 minutes and can quickly coagulate and harden between 100 and 180 minutes. The filling material has better properties such as rapid setting and early strength; by using the double modification technology of plasma treatment and silane coupling agent, the dispersion of fibers in the filling material is significantly improved. The retention rate of the compressive strength of the material is more than 98%, and the expansion rate is less than 4%. This not only enhances the stability and durability of the filling body, but also has important significance for improving the reliability and safety of mine support, making it more adaptable to complex mine environments and engineering requirements.

[0130] It can be seen from the comparison of Examples 1, 10-15 that in the filling material, the length of the fiber has a certain influence on the retention rate of the compressive strength of the filling material. Different fiber lengths affect the dispersion of the fiber in the filling material, can be more effectively combined with the material matrix, form more anchoring points, and thus improve the overall retention rate of the compressive strength of the filling material.

[0131] Compared with Example 1, in Comparative Example 1, no modified fiber was added, and in Comparative Example 2, unmodified fiber was used. The compressive strength retention rate of the filling material decreased significantly. The present invention adopts a dual modification technology of plasma treatment and silane coupling agent, which significantly improves the dispersibility of the fiber in the filling material. Plasma treatment can effectively change the properties of the fiber surface and increase its surface energy, while the silane coupling agent acts as a bridging agent to further promote the compatibility and adhesion between the fiber and the binder. Even under the influence of the external environment, such as long-term immersion in water, it can maintain a high strength, that is, it has an excellent compressive strength retention rate, enhancing the stability and durability of the filling body.

[0132] Compared with Example 1, in Comparative Example 3, the surface was not etched with an acidic solution, in Comparative Example 4, the step of S3 plasma treatment was omitted, and in Comparative Example 5, the step of S4 silane coupling agent treatment was omitted. The compressive strength retention rate of the filling materials in Comparative Examples 3 - 5 decreased significantly, and the expansion rate increased significantly because of the decreased compatibility between the fiber and the binder.

[0133] Through the comparative analysis of Example 1 and Comparative Examples 1 - 5, it can be found that for the filling material using modified fiber in the present invention, there is no significant change in the initial setting time, but the final setting time is significantly shortened, indicating that the modified fiber can accelerate the hardening process of the filling material, thereby improving the construction efficiency and the early use performance of the material. This also means that in practical engineering applications, subsequent construction or use can be carried out earlier, further optimizing the construction process and time arrangement.

[0134] The comparative analysis of Example 1 and Comparative Example 6 reveals that the synergistic effect of the modified fiber and gypsum in the present invention significantly improves the performance of the filling material. This combination not only effectively increases the compressive strength retention rate of the material but also reduces the expansion rate of the material. This improvement helps to enhance the stability and durability of the filling material, especially in application scenarios under greater pressure or in dynamic environments. Through this optimization, the filling material can better adapt to different geological conditions and engineering requirements, improving its applicability and reliability in practical engineering.

[0135] The above embodiments are only the preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantive changes and substitutions made by those skilled in the art based on the present invention belong to the scope of protection required by the present invention.

Claims

1. A modified fiber mine filling material, characterized in that, The materials include the following raw materials in parts by weight: 35-75 parts of cement clinker, 10-20 parts of solid waste, 0.1-3 parts of retarder, 1-5 parts of early strength agent, 20-45 parts of modified fiber, 5-15 parts of accelerating agent, 10-20 parts of gypsum, 0.1-3 parts of water reducing agent, and 0.5-5 parts of suspending agent; The preparation method of the modified fiber is as follows: S1: Clean the fiber and dry it at 90-120°C for 2-5 h; S2: Place the fiber obtained in step S1 in an acidic solution at 40-90°C, immerse it and ultrasonically oscillate for 30-60 minutes; S3: Filter out the fiber in step S2, dry it, and treat it with plasma for 2-10 min; S4: Immerse the fiber in step S3 in a solution containing a silane coupling agent for 10-30 minutes, wash and filter, and dry to obtain the required modified fiber; The fiber includes at least one of glass fiber, polyester fiber, polyamide fiber, polyvinyl alcohol fiber, polyacrylonitrile fiber, polypropylene fiber, polyvinyl chloride fiber, aluminum silicate fiber, and basalt fiber, and the fiber length is 10-25 mm; The silane coupling agent includes at least one of γ-aminopropyltriethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; The cement clinker includes at least one of aluminate cement clinker, sulphoaluminate cement clinker, ferri-aluminate cement clinker, and fluoroaluminate cement clinker.

2. The modified fiber mine filling material according to claim 1, wherein, The solid waste includes at least one of steel slag powder, copper slag powder, fly ash, carbide slag, and coal gangue.

3. The modified fiber mine filling material according to claim 1, wherein The retarder includes at least one of sodium gluconate, borax, or citric acid; the early strength agent includes at least one of calcium chloride, calcium sulfate, water glass, or triethanolamine; the accelerating agent includes at least one of sodium metaaluminate, sodium sulfate, or sodium carbonate.

4. The modified fiber mine filling material according to claim 1, characterized in that The gypsum includes at least one of raw gypsum, desulfurized gypsum, phosphogypsum, and fluorogypsum.

5. The modified fiber mine filling material according to claim 1, characterized in that, The suspending agent includes at least one of sodium carboxymethyl cellulose, water-soluble polyvinyl alcohol, or hydroxypropyl methylcellulose.

6. The modified fiber mine filling material according to claim 1, characterized in that, The water reducing agent includes at least one of naphthalene-based water reducing agent, melamine water reducing agent, or polycarboxylate water reducing agent.

7. A method for preparing the modified fiber mining filling material according to any one of claims 1 to 6, characterized in that: Mix 35-75 parts of cement clinker, 10-20 parts of solid waste, 0.1-3 parts of retarder, 1-5 parts of early strength agent, 20-45 parts of modified fiber, 5-15 parts of accelerating agent, 10-20 parts of gypsum, 0.1-3 parts of water reducing agent, and 0.5-5 parts of suspending agent evenly, add 100-600 parts of water and stir to mix, then the modified fiber mine filling material is obtained.

8. Use of the modified fiber mine filling material according to any one of claims 1 to 6 in mine filling support, characterized in that, Transport the formed filling material to the area of the mine that needs filling and support.

Images