Coal gangue-based glass fiber and preparation method thereof

Abstract

The invention relates to a coal gangue-based glass fiber and a preparation method thereof, belongs to the technical field of comprehensive utilization of solid wastes, and solves the technical problems of high additional value and industrial utilization of coal gangue, and adopts the technical scheme that the coal gangue-based glass fiber comprises the following components in parts by weight: 10 parts of coal gangue; 1-3 parts of quartz sand; 1-2 parts of dolomite; 0.1 to 0.5 part of an additive; the preparation method of the coal gangue-based glass fiber comprises the processes of raw material crushing, coal gangue-based powder pretreatment, mixing and molding, two-step heating and melting, wire drawing and molding, cooling and fiber forming, and sizing and drying. The preparation method has the advantages of wide raw material source, low cost, simple preparation process, easy realization of industrial production, excellent performance of the obtained glass fiber and the like, and the successful implementation of the preparation method not only can realize effective utilization of the coal gangue, but also can provide a new raw material source and a new process route for the glass fiber industry; the method has important economic and social significance.

Description

Technical Field

[0001] The present invention belongs to the technical field of comprehensive utilization of solid waste, and particularly relates to a coal gangue-based glass fiber and a preparation method thereof. Background Art

[0003] At present, certain progress has been made in the research on the comprehensive utilization of coal gangue. Some researchers have attempted to use coal gangue in fields such as building materials, road base materials, and soil conditioners. These attempts have, to a certain extent, alleviated the environmental problems caused by the accumulation of coal gangue and found new application ways for it. However, despite these research achievements, the further utilization of coal gangue to prepare high-performance and high-value-added materials is still rare.

[0004] As an important inorganic non-metallic material, glass fiber has a series of excellent properties such as high strength, corrosion resistance, high temperature resistance, and good insulation, and is widely used in many fields such as construction, transportation, electronics, communication, and aerospace. The traditional raw materials for preparing glass fiber mainly rely on natural mineral resources such as pyrophyllite and quartz sand. However, with the irreversibility of resource utilization and the continuous improvement of ecological and environmental protection requirements, finding new, sustainable, and inexpensive raw material sources to replace precious natural mineral resources has become an important challenge faced by the glass fiber industry.

[0005] At present, there are also some methods for processing coal gangue into inorganic fibers. For example, the patent document "A glass fiber formulation containing coal gangue" (application publication number: CN 117510082 A) discloses the application of coal gangue in the production of glass fiber, expanding the raw material sources of glass fiber. However, in this method, coal gangue is only used as a small amount of ingredient (0.05 - 1.5 wt%), so large-scale utilization of coal gangue cannot be achieved. Another example is the patent document "A method for producing nano-inorganic fibers from coal gangue" (application publication number: CN 108218239 A), which discloses that nano-fibers are obtained by melting coal gangue (50% - 70%), slag (20% - 40%), and silica (10%), centrifugal fiber formation, cotton collection, and slag removal, which can realize the deep processing of coal gangue to form inorganic fibers with good elasticity and toughness. However, the fibers prepared by this method are short fibers and continuous long glass fibers cannot be prepared, and the added value is relatively low. Summary of the Invention

[0006] The main object of the present invention is to overcome the deficiencies in the prior art, solve the technical problems of high-value utilization and industrial utilization of coal gangue, effectively utilize coal gangue, reduce the production cost of glass fiber, and at the same time ensure the quality and performance of glass fiber. The present invention provides a coal gangue-based glass fiber and a preparation method thereof. The present invention can realize the high-value utilization of coal gangue, find new application ways for it in the field of high-performance materials, process coal gangue into continuous glass fiber, and is expected to realize the low-cost preparation of glass fiber while realizing the comprehensive utilization of coal gangue, and achieve good economic, social and environmental benefits.

[0007] The present invention is achieved through the following technical solutions: A coal gangue-based glass fiber, the composition and its weight ratio are as follows: Coal gangue: 10 parts; quartz sand: 1 - 3 parts; dolomite: 1 - 2 parts; additive: 0.1 - 0.5 parts. It should be noted that according to the records in the background art part, the amount of coal gangue in the prior art is less than 1.5%, while the amount of coal gangue in the present invention is greatly increased, and the performance of the glass fiber can still be guaranteed. From the perspective of the utilization of coal gangue solid waste, such progress is remarkable.

[0008] Further, the sum of the weights of SiO 2 and A1 2 O 3 in the coal gangue is not less than 60% of the total weight of the coal gangue, and the weight ratio of SiO 2 / A1 2 O 3 is greater than 2; the content of C element in the coal gangue is less than 20% of the total weight of the coal gangue.

[0009] Further, the quartz sand is quartz sand with a SiO 2 content higher than 90%.

[0010] Further, the dolomite is dolomite with a CaO content higher than 30% and a MgO content higher than 20%.

[0011] Further, the additive is one or more of calcium oxide, boron oxide or titanium dioxide.

[0012] Further, the coal gangue-based glass fiber is continuous long glass fiber, and the diameter of the coal gangue-based glass fiber is 6um - 10um.

[0013] A preparation method of the coal gangue-based glass fiber as described above, including raw material crushing, pretreatment of coal gangue-based powder, mixing and forming, two-step heating and melting, wire drawing and forming, cooling and fibrillation, and sizing and drying processes. The specific steps are as follows: S1. Raw material crushing: Weigh coal gangue, quartz sand, dolomite, and additive raw materials respectively and crush them to a particle size less than 80 mesh for standby. Raw material crushing is the first step in preparing continuous glass fiber and is also the key to ensuring the smooth progress of subsequent processes. In this step, first, coal gangue and other raw materials need to be crushed into powder particles suitable for subsequent melting. S2. Pretreatment of coal gangue powder: Magnetically separate and remove iron from the coal gangue powder prepared in step S1, then place it in a heating furnace and conduct heat treatment in an inert protective atmosphere. The heating temperature is 500°C - 600°C, and the heat preservation time is 5 min - 15 min. After the heat preservation ends, take out the coal gangue powder and cool it to below 100°C by means of indirect cooling that is not in direct contact with the cooling medium. Sulfur, iron, and other volatile substances contained in coal gangue are not conducive to the production of glass fiber. Therefore, the crushed coal gangue also needs to be magnetically separated to remove ferromagnetic substances in the gangue. On this basis, heat pretreatment is also required to remove volatile substances such as sulfur, reducing harmful substances entering the molten liquid during the subsequent melting process. S3. Mixing and forming: Weigh quartz sand, dolomite, additives, and the coal gangue prepared in step S2 according to the composition and weight ratio of coal gangue-based glass fiber, put them into a stirring and forming device for stirring, mixing, and forming to obtain strip-shaped green material. The diameter of the strip-shaped green material is 15 mm, and the length is 20 mm - 30 mm. Since the chemical composition of coal gangue is somewhat different from that of glass fiber raw materials, appropriate amounts of quartz sand, dolomite, additives, or other auxiliary raw materials also need to be added to meet the requirements of glass fiber production. S4. Two-step heating and melting: Place the strip-shaped green material prepared in step S3 in a heating furnace, set the heating rate of the heating furnace to 20°C / min - 30°C / min. After the heating furnace is heated to 1200°C - 1400°C, keep it warm for 10 - 30 minutes. After the heat preservation ends, discharge the liquid material from the liquid discharge port of the heating furnace into a high-temperature homogenizing crucible. The heating furnace continues to heat up to 1500°C - 1600°C and keeps it warm for 10 - 30 minutes to further heat and melt the non-liquid material remaining in the heating furnace, and then discharge the liquid material into the high-temperature homogenizing crucible for the second time. The melting process is a crucial step in melting the strip-shaped raw materials into glass liquid. In this step, gangue needs to be fed into a high-temperature furnace together with other auxiliary raw materials for melting. The temperature of the furnace needs to be controlled within an appropriate range to ensure that the useful components in the gangue can be fully melted and converted into glass liquid. It should be noted that the temperature control during the melting process is of vital importance. Excessive temperature may cause the volatilization loss of useful components in the melt, affecting the quality of glass fibers; while too low temperature may lead to too high viscosity of the melt, making it difficult to fiberize smoothly. To achieve the full melting of the materials without causing the volatilization of useful components, the melting process is divided into two steps: first, separate the materials that can be melted at 1200 - 1400 degrees, and then continue to raise the temperature to about 1500 - 1600 degrees to melt the remaining components. Finally, the two parts of the melted materials are stirred and mixed, and the bubbles are removed by vacuum defoaming instead of using clarifying agents. Since clarifying agents are not used during the melting process, the quality of the glass liquid is guaranteed, ensuring that it can be drawn into high-performance glass fiber rovings; S5. Drawing and forming: The liquid material in the high-temperature resistant homogenizing crucible is stirred, homogenized and vacuum defoamed to form a uniform molten glass liquid; then, the molten glass liquid is ejected through a nozzle with a pore size of 5 - 10 microns to form uniform and continuous glass fiber filaments; S6. Cooling and fiberizing: Control the cooling rate of the air bath to be within the range of 30℃ - 200℃ per minute, and cool the glass fiber filaments prepared in step S5 through the air bath; Fiberization is the last step in converting the molten glass liquid into continuous glass fibers. In this step, the molten glass liquid needs to be ejected through a specific nozzle to form filaments. After the ejected glass filaments leave the nozzle, they will quickly cool and solidify, finally forming continuous glass fibers.

[0014] The cooling rate has an important impact on the structure and performance of glass fibers. Too fast cooling rate may cause stress inside the glass fibers, affecting their strength and toughness; while too slow cooling rate may cause defects on the surface of the glass fibers, affecting their corrosion resistance and insulation. To well control the cooling rate, the ejected glass filaments are cooled through the air bath, and the cooling rate is controlled within a certain range, thereby ensuring the quality of the glass fibers. The cooled fibers are then coated with a sizing agent and wound and dried to obtain the final continuous glass fiber product.

[0015] S7. Sizing and drying: Coat the surface of the glass fiber filaments prepared in step S6 with a sizing agent, and then wind and dry them to produce gangue-based glass fibers.

[0016] The coal gangue-based glass fiber prepared by the present invention has properties comparable to those of E-glass fiber, but its thermal stability is superior to that of E-glass fiber. It can be widely applied in multiple fields such as construction, transportation, electronics, communication, aerospace, etc., providing high-performance and high-value-added materials for related industries.

[0017] Further, in the step S7, the composition and weight ratio of the sizing agent are as follows: water 93.5%, polyurethane film-forming agent 4%, silane coupling agent 1%, mineral oil lubricant 1%, surfactant 0.5%.

[0018] The beneficial effects of the present invention are as follows: (1) The present invention can industrially utilize the solid waste of coal gangue, reduce environmental pollution, and realize the recycling of resources; (2) Compared with the traditional glass fiber production method, this method reduces the dependence on natural mineral raw materials, thereby reducing the production cost.

[0019] In summary, the present invention has the advantages of wide raw material sources, low cost, simple preparation process, easy realization of industrial production, and excellent properties of the obtained glass fiber. The successful implementation of this method can not only effectively utilize coal gangue, but also provide a new raw material source and process route for the glass fiber industry, having important economic and social significance. Detailed implementation manners

[0020] The present invention will be further described in detail below in conjunction with embodiments. Embodiment 1

[0021] A preparation method of coal gangue-based glass fiber includes the following steps: S1. Raw material crushing: Weigh coal gangue, quartz sand, dolomite, and additive raw materials respectively and crush them to a particle size less than 80 mesh for standby; Among them, the sum of the weights of SiO 2 and A1 2 O 3 in the coal gangue is not less than 60% of the total weight of the coal gangue, and the weight ratio of SiO 2 / A1 2 O 3 is greater than 2; the C element content in the coal gangue is less than 20% of the total weight of the coal gangue; The quartz sand is quartz sand with a SiO 2 content higher than 90%; The dolomite is dolomite with a CaO content higher than 30% and a MgO content higher than 20%; The additive is calcium oxide and boron oxide, and the mass ratio is 1:1; S2. Pretreatment of coal gangue powder: The coal gangue powder prepared in step S1 is subjected to magnetic separation to remove iron, and then placed in a heating furnace for heat treatment in an inert protective atmosphere. The heating temperature is 500 °C and the heat preservation time is 15 min. After the heat preservation is completed, the coal gangue powder is taken out and cooled to below 100 °C by a jacketed cooler (using cooling water as the cooling medium). S3. Mixing and forming: Weigh quartz sand, dolomite, additives and the coal gangue prepared in step S2 according to the composition and weight ratio of the coal gangue-based glass fiber. In this Example 1, the composition and weight ratio of the coal gangue-based glass fiber are: coal gangue: quartz sand: dolomite: additives = 10:2:2:1. Put them into a stirring and forming device for stirring, mixing and forming to obtain strip-shaped green materials. The diameter of the strip-shaped green materials is 15 mm and the length is 20 mm. S4. Two-step heating and melting: Place the strip-shaped green materials prepared in step S3 in a heating furnace, set the heating rate of the heating furnace to 20 °C / min. After the heating furnace is heated to 1200 °C, keep it warm for 30 minutes. After the heat preservation is completed, discharge the liquid material from the liquid discharge port of the heating furnace into a high-temperature homogenizing crucible. The heating furnace continues to heat up to 1600 °C and keeps it warm for 20 minutes to further heat and melt the non-liquid materials remaining in the heating furnace, and then discharge the liquid material into the high-temperature homogenizing crucible for the second time. S5. Drawing and forming: The liquid material in the high-temperature homogenizing crucible is stirred and homogenized and vacuum degassed to form a uniform molten glass liquid. Then, the molten glass liquid is ejected through a nozzle with a pore diameter of 10 microns to form uniform and continuous glass fiber filaments. S6. Cooling and fiber forming: Control the cooling rate of the air bath to be maintained at 30 °C per minute, and cool the glass fiber filaments prepared in step S5 through the air bath. S7. Sizing and drying: Coat the surface of the glass fiber filaments prepared in step S6 with a sizing agent, and then wind and dry to obtain coal gangue-based glass fiber. The strength of the coal gangue-based glass fiber prepared in this Example 1 is 3250 MPa. Example 2

[0022] A preparation method of coal gangue-based glass fiber includes the following steps: S1. Raw material crushing: Weigh coal gangue, quartz sand, dolomite and additive raw materials respectively and crush them to a particle size less than 80 mesh for standby. In this Example 2, the composition and proportion of the main phases in coal gangue, quartz sand and dolomite are the same as those in Example 1. The additives are calcium oxide, boron oxide and titanium dioxide, and the mass ratio is 1:1:1. S2. Pretreatment of coal gangue powder: The coal gangue powder prepared in step S1 is subjected to magnetic separation to remove iron, and then placed in a heating furnace for heat treatment in an inert protective atmosphere. The heating temperature is 600 °C and the heat preservation time is 5 min. After the heat preservation is completed, the coal gangue powder is taken out and cooled to below 100 °C by a jacketed cooler (using cooling water as the cooling medium); S3. Mixing and forming: Weigh quartz sand, dolomite, additives and the coal gangue prepared in step S2 according to the composition and weight ratio of the coal gangue-based glass fiber. In this Example 2, the composition and weight ratio of the coal gangue-based glass fiber are: coal gangue: quartz sand: dolomite: additives = 10:3:1:0.5; put them into a stirring and forming device for stirring, mixing and forming to obtain a strip-shaped green material. The diameter of the strip-shaped green material is 15 mm and the length is 25 mm; S4. Two-step heating and melting: Place the strip-shaped green material prepared in step S3 in a heating furnace, set the heating rate of the heating furnace to 30 °C / min, heat the heating furnace to 1400 °C and keep it warm for 10 minutes. After the heat preservation is completed, discharge the liquid material from the liquid discharge port of the heating furnace into a high-temperature homogenizing crucible; the heating furnace continues to heat up to 1600 °C and keep it warm for 15 minutes, further heat and melt the non-liquid material remaining in the heating furnace, and then discharge the liquid material into the high-temperature homogenizing crucible for the second time; S5. Drawing and forming: The liquid material in the high-temperature homogenizing crucible is stirred, homogenized and vacuum degassed to form a uniform molten glass liquid; then, the molten glass liquid is ejected through a nozzle with a pore diameter of 8 microns to form uniform and continuous glass fiber filaments; S6. Cooling and fiber formation: Control the cooling rate of the air bath to be maintained at 100 °C per minute, and cool the glass fiber filaments prepared in step S5 through the air bath; S7. Sizing and drying: Coat the surface of the glass fiber filaments prepared in step S6 with a sizing agent, and then wind and dry to obtain coal gangue-based glass fiber. The strength of the coal gangue-based glass fiber prepared in this Example 2 is 3300 MPa. Example 3

[0023] A preparation method of coal gangue-based glass fiber, comprising the following steps: S1. Raw material crushing: Weigh coal gangue, quartz sand, dolomite and additive raw materials respectively and crush them to a particle size less than 80 mesh for standby; In this Example 3, the composition and proportion of the main phases in coal gangue, quartz sand and dolomite are the same as those in Example 1. The additives are boron oxide and titanium dioxide, and the mass ratio is 1:1; S2. Pretreatment of coal gangue powder: The coal gangue powder prepared in step S1 is subjected to magnetic separation to remove iron, and then placed in a heating furnace for heat treatment in an inert protective atmosphere. The heating temperature is 550 °C and the heat preservation time is 10 min. After the heat preservation is completed, the coal gangue powder is taken out and cooled to below 100 °C by a jacketed cooler (using cooling water as the cooling medium). S3. Mixing and forming: Weigh quartz sand, dolomite, additives and the coal gangue prepared in step S2 according to the composition and weight ratio of the coal gangue-based glass fiber. In this Example 3, the composition and weight ratio of the coal gangue-based glass fiber are: coal gangue: quartz sand: dolomite: additives = 10:1:1:1. Put them into a stirring and forming device for stirring, mixing and forming to obtain strip-shaped green materials. The diameter of the strip-shaped green materials is 15 mm and the length is 30 mm. S4. Two-step heating and melting: Place the strip-shaped green materials prepared in step S3 in a heating furnace, set the heating rate of the heating furnace to 25 °C / min. After the heating furnace is heated to 1300 °C, keep it warm for 20 minutes. After the heat preservation is completed, discharge the liquid material from the liquid discharge port of the heating furnace into a high-temperature homogenizing crucible. The heating furnace continues to heat up to 1550 °C and keeps it warm for 30 minutes to further heat and melt the non-liquid materials remaining in the heating furnace, and then discharge the liquid material into the high-temperature homogenizing crucible for the second time. S5. Drawing and forming: The liquid material in the high-temperature homogenizing crucible is stirred and homogenized and vacuum degassed to form a uniform molten glass liquid. Then, the molten glass liquid is ejected through a nozzle with a pore diameter of 6 microns to form uniform and continuous glass fiber filaments. S6. Cooling and fiber forming: Control the cooling rate of the air bath to be maintained at 100 °C per minute, and cool the glass fiber filaments prepared in step S5 through the air bath. S7. Sizing and drying: Coat the surface of the glass fiber filaments prepared in step S6 with a sizing agent, and then wind and dry to obtain coal gangue-based glass fiber. The strength of the coal gangue-based glass fiber prepared in this Example 3 is 3500 MPa. Example 4

[0024] A preparation method of coal gangue-based glass fiber includes the following steps: S1. Raw material crushing: Weigh coal gangue, quartz sand, dolomite and additive raw materials respectively and crush them to a particle size less than 80 mesh for standby. In this Example 4, the composition and proportion of the main phases in coal gangue, quartz sand and dolomite are the same as those in Example 1. The additives are boron oxide and titanium dioxide, and the mass ratio is 1:0.5. S2. Pretreatment of coal gangue powder: The coal gangue powder prepared in step S1 is subjected to magnetic separation to remove iron, and then placed in a heating furnace for heat treatment in an inert protective atmosphere. The heating temperature is 500 °C and the heat preservation time is 8 min. After the heat preservation is completed, the coal gangue powder is taken out and cooled to below 100 °C by a jacketed cooler (using cooling water as the cooling medium); S3. Mixing and molding: Weigh quartz sand, dolomite, additives and the coal gangue prepared in step S2 according to the composition and weight ratio of the coal gangue-based glass fiber. In this Example 4, the composition and weight ratio of the coal gangue-based glass fiber are: coal gangue: quartz sand: dolomite: additives = 10:2:1:0.5; Put them into a stirring and molding device for stirring, mixing and molding to obtain strip-shaped green materials. The diameter of the strip-shaped green materials is 15 mm and the length is 25 mm; S4. Two-step heating and melting: Place the strip-shaped green materials prepared in step S3 in a heating furnace, set the heating rate of the heating furnace to 28 °C / min, heat the heating furnace to 1250 °C and keep it warm for 25 minutes. After the heat preservation is completed, discharge the liquid material from the liquid discharge port of the heating furnace into a high-temperature homogenizing crucible; The heating furnace continues to heat up to 1600 °C and keep it warm for 10 minutes to further heat and melt the non-liquid materials remaining in the heating furnace, and then discharge the liquid materials into the high-temperature homogenizing crucible for the second time; S5. Drawing and forming: The liquid material in the high-temperature homogenizing crucible is stirred, homogenized and vacuum degassed to form a uniform molten glass liquid; Then, the molten glass liquid is ejected through a nozzle with a pore diameter of 10 microns to form uniform and continuous glass fiber filaments; S6. Cooling and fiber forming: Control the cooling rate of the air bath to be maintained at 200 °C per minute, and cool the glass fiber filaments prepared in step S5 through the air bath; S7. Sizing and drying: Coat the surface of the glass fiber filaments prepared in step S6 with a sizing agent, and then wind and dry to obtain coal gangue-based glass fiber. The strength of the coal gangue-based glass fiber prepared in this Example 4 is 3260 MPa. Example 5

[0025] A preparation method of coal gangue-based glass fiber includes the following steps: S1. Raw material crushing: Weigh coal gangue, quartz sand, dolomite and additive raw materials respectively and crush them to a particle size less than 80 mesh for standby; In this Example 2, the composition and proportion of the main phases in coal gangue, quartz sand and dolomite are the same as those in Example 1. The additives are calcium oxide, boron oxide and titanium dioxide, and the mass ratio is 0.5:1:1; S2. Pretreatment of coal gangue powder: The coal gangue powder prepared in step S1 is subjected to magnetic separation to remove iron, and then placed in a heating furnace for heat treatment in an inert protective atmosphere. The heating temperature is 560 °C and the heat preservation time is 10 min. After the heat preservation is completed, the coal gangue powder is taken out and cooled to below 100 °C by a jacketed cooler (using cooling water as the cooling medium). S3. Mixing and forming: Weigh quartz sand, dolomite, additives and the coal gangue prepared in step S2 according to the composition and weight ratio of the coal gangue-based glass fiber. In this Example 5, the composition and weight ratio of the coal gangue-based glass fiber are: coal gangue: quartz sand: dolomite: additives = 10:2:2:0.5. Put them into a stirring and forming device for stirring, mixing and forming to obtain a strip-shaped green material. The diameter of the strip-shaped green material is 15 mm and the length is 30 mm. S4. Two-step heating and melting: Place the strip-shaped green material prepared in step S3 in a heating furnace, set the heating rate of the heating furnace to 22 °C / min. After the heating furnace is heated to 1300 °C, keep it at this temperature for 15 minutes. After the heat preservation is completed, discharge the liquid material from the liquid discharge port of the heating furnace into a high-temperature homogenizing crucible. The heating furnace continues to heat up to 1550 °C and keeps it at this temperature for 26 minutes to further heat and melt the non-liquid material remaining in the heating furnace, and then discharge the liquid material into the high-temperature homogenizing crucible for the second time. S5. Drawing and forming: The liquid material in the high-temperature homogenizing crucible is stirred, homogenized and vacuum degassed to form a uniform molten glass liquid. Then, the molten glass liquid is ejected through a nozzle with a pore diameter of 6 microns to form uniform and continuous glass fiber filaments. S6. Cooling and fiber formation: Control the cooling rate of the air bath to be maintained at 100 °C per minute, and cool the glass fiber filaments prepared in step S5 through the air bath. S7. Sizing and drying: Coat the surface of the glass fiber filaments prepared in step S6 with a sizing agent, and then wind and dry them to obtain the coal gangue-based glass fiber. The strength of the coal gangue-based glass fiber prepared in this Example 5 is 3450 MPa.

[0026] As mentioned above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A coal gangue-based glass fiber, characterized in that: The composition and weight ratio of the gangue-based glass fiber are as follows: Coal gangue: 10 parts; Quartz sand: 1-3 parts; Dolomite: 1-2 parts; Additives: 0.1-0.5 parts.

2. The gangue-based glass fiber according to claim 1, characterized in that: The sum of the weights of SiO2 and A12O3 in the gangue is not less than 60% of the total weight of the gangue, and the weight ratio of SiO2 / A12O3 is greater than 2; the C element content in the gangue is less than 20% of the total weight of the gangue.

3. The gangue-based glass fiber according to claim 1, characterized in that: The quartz sand is quartz sand with SiO2 content higher than 90%.

4. The gangue-based glass fiber according to claim 1, characterized in that: The dolomite has a CaO content higher than 30% and a MgO content higher than 20%.

5. The gangue-based glass fiber according to claim 1, characterized in that: The additive is one or more of calcium oxide, boron oxide or titanium dioxide.

6. The gangue-based glass fiber according to claim 1, characterized in that: The gangue-based glass fiber is a continuous long glass fiber, and the diameter of the gangue-based glass fiber is 6um-10um.

7. A method for preparing gangue-based glass fiber according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Raw material crushing: Weigh coal gangue, quartz sand, dolomite and additive raw materials respectively and crush them to a particle size of less than 80 mesh for later use; S2, pretreatment of coal gangue powder: the coal gangue powder prepared in step S1 is subjected to magnetic separation to remove iron, and then placed in a heating furnace for heating treatment in an inert protective atmosphere at a heating temperature of 500°C-600°C for a holding time of 5min-15min; after the holding is completed, the coal gangue powder is taken out and cooled to below 100°C by an indirect cooling method without direct contact with a cooling medium; S3, mixing and molding: according to the composition and weight ratio of the gangue-based glass fiber, quartz sand, dolomite, additives and the gangue prepared in step S2 are weighed, and put into a stirring and molding device for stirring, mixing and molding to obtain a strip raw material, the diameter of the strip raw material is 15 mm, and the length is 20 mm-30 mm; S4, two-step heating and melting: placing the strip raw material prepared in step S3 in a heating furnace, setting the heating rate of the heating furnace to 20°C / min-30°C / min, heating the heating furnace to 1200°C-1400°C and then keeping it warm for 10-30 minutes, and after the insulation is completed, discharging the liquid material from the liquid discharge port of the heating furnace into a high-temperature resistant homogenizing crucible; the heating furnace continues to heat up to 1500°C-1600°C and keep it warm for 10-30 minutes, further heating and melting the non-liquid material remaining in the heating furnace, and then discharging the liquid material into the high-temperature resistant homogenizing crucible for a second time; S5, wire drawing: the liquid material in the high temperature resistant homogenizing crucible is stirred, homogenized and vacuum degassed to form a uniform molten glass liquid; then, the molten glass liquid is sprayed through a nozzle with an aperture of 5-10 microns to form uniform and continuous glass fiber filaments; S6, cooling and fiberizing: controlling the cooling rate of the air bath to be maintained in the range of 30°C-200°C per minute, and cooling the glass fiber filaments prepared in step S5 through the air bath; S7, sizing and drying: coating the surface of the glass fiber filaments prepared in step S6 with a sizing agent, and then winding and drying the filaments to obtain gangue-based glass fibers.

8. The method for preparing gangue-based glass fiber according to claim 7, characterized in that: In step S7, the composition and weight ratio of the wetting agent are: 93.5% water, 4% polyurethane film-forming agent, 1% silane coupling agent, 1% mineral oil lubricant, and 0.5% surfactant.