Fireproof flame-retardant basalt fiber pipeline for large ship and preparation method of fireproof flame-retardant basalt fiber pipeline

Abstract

The invention discloses a fireproof flame-retardant basalt fiber pipeline for a large ship and a preparation method of the fireproof flame-retardant basalt fiber pipeline, and belongs to the technical field of composite material pipelines. A siloxane coating layer is constructed on the surface of basalt fiber through hydrolytic condensation reaction of tetraethoxysilane, so that the interfacial compatibility of the fiber and an organic matrix can be effectively improved; the surface roughness of the basalt fibers is improved, the fibers are prevented from being agglomerated in a matrix, ammonium polyphosphate is fixed through the silicon dioxide coating layer, the mechanical property and structural stability of the pipeline are improved, and the flame retardant effect is prolonged; ammonium polyphosphate is an efficient intumescent flame retardant, is combined with the basalt composite fiber in a nitrogen atmosphere, and can form a compact carbon layer when being heated to isolate oxygen and heat transfer; meanwhile, the basalt fibers have inorganic high-temperature-resistant characteristics, and the basalt fibers and the basalt fibers have a synergistic effect, so that the pipeline is endowed with excellent fireproof and flame-retardant effects, and the fireproof safety requirements of large ships are met.

Description

Technical Field

[0001] This invention belongs to the field of composite material pipeline technology, specifically a fire-resistant and flame-retardant basalt fiber pipeline for large ships and its preparation method. Background Technology

[0002] Pipelines are widely used in building pipelines, petroleum, power, chemical, papermaking, urban water supply and drainage, factory wastewater treatment, seawater desalination, and gas transmission networks. Meanwhile, pressure pipelines are involved in various industries. Due to the high velocity and large flow rate of the transported media, the continuous impact, abrasion, and corrosion of the pipe walls caused by the transported media can lead to fatigue in high-temperature pipelines, eventually causing them to wear through. Therefore, their safety requirements are paramount. Traditional steel and plastic pipelines have poor corrosion resistance, fire resistance, high-temperature resistance, and weather resistance, and can no longer meet current demands. They are particularly inadequate for transporting highly corrosive fluids, fluids in harsh climates, fluids with poor flowability, and high-temperature fluids.

[0003] Currently, various composite pipes have emerged, such as fiber-reinforced pipes made from thermoplastic polymers and fibers, and steel-lined PTFE pipes and polyethylene composite pipes made from polymers and steel. These composite pipes have improved their high-temperature resistance to some extent, but they still cannot meet the increasingly stringent application requirements. Furthermore, these composite pipes have poor corrosion resistance, which limits their use in actual production processes.

[0004] Chinese patent CN101694251A discloses a self-heating and high-temperature resistant oil pipeline and its preparation method. The heating layer is composed of glass fiber and epoxy resin, and the heating layer is composed of carbon fiber and epoxy resin, achieving both heat insulation and high-temperature resistance. However, its high-temperature resistance and flame retardant properties still need improvement. Invention patent application number 201310023074.2 discloses a continuous fiber-reinforced thermoplastic composite high-pressure pipeline. The inner and outer walls are made of thermoplastic resin materials; the middle layer is a continuous fiber resin reinforcement layer composed of multiple layers of fiber resin thermoplastic composite. It has high heating performance and stronger impact resistance, but still cannot meet the increasingly high demands of modern production for high-temperature resistance, and it does not address improving corrosion and fire resistance. Summary of the Invention

[0005] The purpose of this invention is to provide a fire-retardant basalt fiber pipe for large ships and its preparation method. By hydrolysis and condensation reaction of tetraethyl orthosilicate, a siloxane coating layer is constructed on the surface of basalt fiber, which can effectively improve the interfacial compatibility between fiber and organic matrix, increase the surface roughness of basalt fiber, and prevent fiber agglomeration in matrix. The ammonium polyphosphate is fixed by the silica coating layer, which improves the mechanical properties and structural stability of the pipe and prolongs the flame retardant effect.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for preparing fire-resistant and flame-retardant basalt fiber pipes for large ships includes the following steps: Flame-retardant basalt composite fibers are fed into an oven for segmented drying. The first stage of drying involves raising the temperature from 20-30℃ to 85-90℃, followed by holding at 85-90℃ for 50-60 minutes. The second stage involves raising the temperature from 85-90℃ to 100-105℃, followed by holding at 100-105℃ for 85-95 minutes. The third stage involves raising the temperature from 100-105℃ to 110-120℃, followed by holding at 110-120℃ for 140-160 minutes to completely evaporate the moisture from the fiber surface. The fibers are then wound into a mesh to form a fiber reinforcement layer. Graphene, polyethylene resin, and phenolic resin are poured onto the fiber reinforcement layer using a forming extrusion device, extruded, and cured to obtain fire-retardant basalt fiber pipes for large ships.

[0007] Furthermore, the ratio of graphene, polyethylene resin, and phenolic resin is 20-22g: 60-70g: 50-55g.

[0008] Furthermore, the specific preparation steps of flame-retardant basalt composite fibers are as follows: Basalt composite fibers, ammonium polyphosphate, and a 50-60% ethanol solution were added to a reactor. Under a nitrogen atmosphere, the mixture was stirred at 50-60℃ and 400-500 r / min for 30-40 min, heated to 80℃, and stirred for 4-5 h. The mixture was then filtered, and the filter cake was washed 2-4 times with deionized water to obtain flame-retardant basalt composite fibers.

[0009] Furthermore, the ratio of basalt composite fiber, ammonium polyphosphate, and ethanol solution is 40-42g: 22-24g: 500-600mL.

[0010] Furthermore, the specific preparation steps of basalt composite fibers are as follows: Basalt fiber, ethanol, deionized water and ammonia are added to a reaction vessel and stirred for 20-30 minutes at 20-25℃ and 500-600 r / min. Then, tetraethyl orthosilicate is added, and the mixture is heated to 40-50℃ and stirred for 2-3 hours. The mixture is then filtered, and the fiber is washed 2-4 times with deionized water and anhydrous ethanol, respectively. The fiber is then vacuum dried at 60-70℃ for 1-2 hours to obtain basalt composite fiber.

[0011] Furthermore, the ratio of basalt fiber, ethanol, deionized water, ammonia and tetraethyl orthosilicate is 50-60g: 600-700mL: 70-80mL: 35-40mL: 80-90mL.

[0012] Furthermore, the specific preparation steps of basalt fiber are as follows: Pretreated basalt, a 3 mol / L hydrochloric acid solution, and 20-25% oxalic acid were added to a high-pressure reactor. The mixture was stirred at 200-220℃ and 500-600 rpm for 8-9 hours, then allowed to cool naturally to room temperature. After filtration, the filter cake was washed 2-4 times with deionized water and anhydrous ethanol, respectively. The product was then vacuum dried at 60-70℃ for 1-2 hours. The product was then frozen at -20℃ to solidify. After thawing, it was sonicated for 40-60 minutes, filtered, and the filter cake was washed 2-4 times with deionized water and anhydrous ethanol, respectively. The product was then vacuum dried at 60-70℃ for 1-2 hours and ground until fluffy to obtain basalt fibers.

[0013] Furthermore, the ratio of pretreated basalt, hydrochloric acid solution, and oxalic acid is 70-80g: 1-2L: 800-900mL.

[0014] Furthermore, the specific preparation steps for pretreated basalt are as follows: Basalt and deionized water are added to a reaction vessel and stirred for 20-30 minutes at 20-25℃ and 500-600 r / min. The mixture is then allowed to stand and soak for 24-26 hours, allowing it to settle naturally. The upper suspension is then filtered, and the filter cake is washed 2-4 times with deionized water and anhydrous ethanol, respectively. The cake is then vacuum dried at 60-70℃ for 1-2 hours to obtain pretreated basalt.

[0015] Furthermore, the ratio of basalt to deionized water is 80-90g:800-900mL.

[0016] The beneficial effects of this invention are: 1. The fire-retardant basalt fiber pipe for large ships prepared by this invention constructs a siloxane coating layer on the surface of basalt fiber through the hydrolysis and condensation reaction of tetraethyl orthosilicate. This can effectively improve the interfacial compatibility between the fiber and the organic matrix, increase the surface roughness of the basalt fiber, prevent the fiber from agglomerating in the matrix, and fix the ammonium polyphosphate using the silica coating layer, thereby improving the mechanical properties and structural stability of the pipe and extending the flame-retardant effect.

[0017] 2. The ammonium polyphosphate introduced in this invention is a highly efficient intumescent flame retardant. When combined with basalt composite fibers in a nitrogen atmosphere, it can form a dense carbon layer when heated, isolating oxygen and heat transfer. At the same time, basalt fibers themselves have inorganic high-temperature resistance properties. The synergistic effect of the two gives the pipeline excellent fireproof and flame-retardant effects, meeting the fire safety requirements of large ships. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: A method for preparing fire-resistant and flame-retardant basalt fiber pipes for large ships, comprising the following steps: S1: Add 80g of basalt and 800mL of deionized water to the reactor, stir for 20min at 20℃ and 500r / min, let stand and soak for 24h, let it settle naturally, take the upper suspension and filter, wash the filter cake twice with deionized water and anhydrous ethanol respectively, and vacuum dry at 60℃ for 1h to obtain pretreated basalt.

[0020] S2: 70g of pretreated basalt, 1L of 3mol / L hydrochloric acid solution and 800mL of 20% oxalic acid were added to a high-pressure reactor and stirred at 200℃ and 500r / min for 8h. After natural cooling to room temperature, the mixture was filtered. The filter cake was washed twice with deionized water and anhydrous ethanol, respectively, and dried under vacuum at 60℃ for 1h. The product was frozen at -20℃ to solidify. After thawing, it was sonicated for 40min and filtered. The filter cake was washed twice with deionized water and anhydrous ethanol, respectively, and dried under vacuum at 60℃ for 1h. The mixture was then ground until fluffy to obtain basalt fibers.

[0021] S3: Add 50g of basalt fiber, 600mL of ethanol, 70mL of deionized water and 35mL of ammonia to a reaction vessel, stir for 20min at 20℃ and 500r / min, then add 80mL of tetraethyl orthosilicate, heat to 40℃, continue stirring for 2h, filter, wash the fiber twice with deionized water and anhydrous ethanol respectively, and vacuum dry at 60℃ for 1h to obtain basalt composite fiber.

[0022] S4: Add 40g of basalt composite fiber, 22g of ammonium polyphosphate and 500mL of 50% ethanol solution to the reactor. Stir at 50℃ and 400r / min for 30min under nitrogen atmosphere, heat to 80℃ and continue stirring for 4h. Filter and wash the filter cake twice with deionized water to obtain flame-retardant basalt composite fiber.

[0023] S5: The flame-retardant basalt composite fiber is fed into an oven for segmented drying. The first stage of drying involves raising the temperature from 20°C to 85°C and then holding it at 85°C for 50 minutes. The second stage involves raising the temperature from 85°C to 100°C and then holding it at 100°C for 85 minutes. The third stage involves raising the temperature from 100°C to 110°C and holding it at 110°C for 140 minutes to completely evaporate the moisture on the fiber surface. The fiber is then wound into a mesh to form a fiber reinforcement layer. 20g of graphene, 60g of polyethylene resin, and 50g of phenolic resin are poured onto the fiber reinforcement layer through a forming extrusion device, extruded, and cured to obtain a fire-retardant basalt fiber pipe for large ships.

[0024] Example 2: A method for preparing fire-resistant and flame-retardant basalt fiber pipes for large ships, comprising the following steps: S1: Add 85g of basalt and 850mL of deionized water to the reactor, stir for 25min at 22.5℃ and 550r / min, let stand and soak for 25h, let it settle naturally, take the upper suspension and filter, wash the filter cake three times with deionized water and anhydrous ethanol respectively, and dry it under vacuum at 65℃ for 1.5h to obtain pretreated basalt.

[0025] S2: 75g of pretreated basalt, 1.5L of 3mol / L hydrochloric acid solution and 850mL of 22.5% oxalic acid were added to a high-pressure reactor and stirred at 210℃ and 550r / min for 8.5h. After natural cooling to room temperature, the mixture was filtered. The filter cake was washed three times with deionized water and three times with anhydrous ethanol. It was then vacuum dried at 65℃ for 1.5h. The product was frozen at -20℃ to solidify. After thawing, it was sonicated for 50min and filtered. The filter cake was washed three times with deionized water and three times with anhydrous ethanol. It was then vacuum dried at 65℃ for 1.5h and ground until fluffy to obtain basalt fibers.

[0026] S3: Add 55g of basalt fiber, 650mL of ethanol, 75mL of deionized water and 37.5mL of ammonia to a reaction vessel, stir for 25min at 22.5℃ and 550r / min, then add 85mL of tetraethyl orthosilicate, heat to 45℃, continue stirring for 2.5h, filter, wash the fiber three times with deionized water and anhydrous ethanol respectively, and vacuum dry at 65℃ for 1.5h to obtain basalt composite fiber.

[0027] S4: Add 41g of basalt composite fiber, 23g of ammonium polyphosphate and 550mL of 55% ethanol solution to the reactor. Stir at 55℃ and 450r / min for 35min under nitrogen atmosphere, heat to 80℃ and continue stirring for 4.5h. Filter and wash the filter cake three times with deionized water to obtain flame-retardant basalt composite fiber.

[0028] S5: The flame-retardant basalt composite fiber is fed into an oven for segmented drying. The first stage of drying involves raising the temperature from 25℃ to 87.5℃ and then holding it at 87.5℃ for 55 minutes. The second stage involves raising the temperature from 87.5℃ to 102.5℃ and then holding it at 102.5℃ for 90 minutes. The third stage involves raising the temperature from 102.5℃ to 115℃ and holding it at 115℃ for 150 minutes to completely evaporate the moisture on the fiber surface. Then, the fiber is wound into a mesh to form a fiber reinforcement layer. 21g of graphene, 65g of polyethylene resin, and 52.5g of phenolic resin are poured onto the fiber reinforcement layer through a forming extrusion device, extruded, and cured to obtain a large-scale fire-retardant basalt fiber pipe for ships.

[0029] Example 3: A method for preparing fire-resistant and flame-retardant basalt fiber pipes for large ships, comprising the following steps: S1: Add 90g of basalt and 900mL of deionized water to the reactor, stir for 30min at 25℃ and 600r / min, let stand and soak for 26h, let it settle naturally, take the upper suspension and filter, wash the filter cake with deionized water and anhydrous ethanol 4 times respectively, and vacuum dry at 70℃ for 2h to obtain pretreated basalt.

[0030] S2: Add 80g of pretreated basalt, 2L of 3mol / L hydrochloric acid solution and 900mL of 25% oxalic acid to a high-pressure reactor. Stir at 220℃ and 600r / min for 9h, cool naturally to room temperature, filter, wash the filter cake with deionized water and anhydrous ethanol 4 times each, dry under vacuum at 70℃ for 2h, freeze the product at -20℃ to solidify, thaw and sonicate for 60min, filter, wash the filter cake with deionized water and anhydrous ethanol 4 times each, dry under vacuum at 70℃ for 2h, grind until fluffy to obtain basalt fibers.

[0031] S3: Add 60g of basalt fiber, 700mL of ethanol, 80mL of deionized water and 40mL of ammonia water to a reaction vessel, stir for 30min at 25℃ and 600r / min, then add 90mL of tetraethyl orthosilicate, heat to 50℃, continue stirring for 3h, filter, wash the fiber 4 times with deionized water and anhydrous ethanol respectively, and vacuum dry at 70℃ for 2h to obtain basalt composite fiber.

[0032] S4: Add 42g of basalt composite fiber, 24g of ammonium polyphosphate and 600mL of 60% ethanol solution to the reactor. Stir at 60℃ and 500r / min for 40min under nitrogen atmosphere, heat to 80℃ and continue stirring for 5h. Filter and wash the filter cake with deionized water 4 times to obtain flame-retardant basalt composite fiber.

[0033] S5: The flame-retardant basalt composite fiber is fed into an oven for segmented drying. The first stage of drying involves raising the temperature from 30℃ to 90℃ and then holding it at 90℃ for 60 minutes. The second stage involves raising the temperature from 90℃ to 105℃ and then holding it at 105℃ for 95 minutes. The third stage involves raising the temperature from 105℃ to 120℃ and holding it at 120℃ for 160 minutes to completely evaporate the moisture on the fiber surface. Then, the fiber is wound into a mesh to form a fiber reinforcement layer. 22g of graphene, 70g of polyethylene resin, and 55g of phenolic resin are poured onto the fiber reinforcement layer through a forming extrusion device, extruded, and cured to obtain a fire-retardant basalt fiber pipe for large ships.

[0034] Comparative Example 1: The difference from Example 3 is that the flame-retardant basalt composite fiber in step S5 is replaced with the basalt composite fiber prepared in step S3.

[0035] Comparative Example 2: The difference from Example 3 is that the basalt composite fiber in step S4 is replaced with the basalt fiber prepared in step S2.

[0036] Performance tests were conducted on the fire-retardant basalt fiber pipes for large ships prepared in Examples 1-3 and Comparative Examples 1-2. The test standards were as follows: hydrostatic pressure test: API Spec 15HR; fatigue test: API Spec 15HR; pressure holding and air tightness test: pressurized to 1.2 times the operating pressure with PN2 for 24 hours; and flame retardant performance (UL94) test.

[0037] The results are shown in Table 1: Table 1 ; As shown in Table 1, the fire-retardant effect in Comparative Example 1 is significantly reduced, failing to meet ship safety standards. The lack of graft modification with ammonium polyphosphate intumescent flame retardant means the pipeline relies solely on the inorganic high-temperature resistance of basalt fiber itself. Without the barrier effect of a dense carbon layer after heating, it cannot effectively isolate oxygen and heat transfer, resulting in a decreased limiting oxygen index. This fails to meet the Class I flame-retardant standard for ship pipelines, making them highly susceptible to combustion and spreading upon contact with open flames, posing a serious fire safety hazard. Without the high-temperature protection of the ammonium polyphosphate carbon layer, the siloxane coating of the basalt composite fiber is prone to thermal decomposition at high temperatures, reducing the pipeline's temperature tolerance and making it unsuitable for high-temperature conditions in ship engine rooms and powerhouses. Under high-temperature environments, the pipeline is prone to softening and deformation, compromising its structural integrity. Ammonium polyphosphate, combined with basalt composite fiber in a nitrogen atmosphere, not only achieves flame retardancy but also reinforces the fiber skeleton. The absence of this step reduces the fiber's structural support, decreases the pipeline's pressure tolerance, and reduces fatigue cycles. Under continuous vibration loads during ship navigation, the pipeline is prone to cracking and deformation, significantly shortening its service life.

[0038] In Comparative Example 2, the absence of a siloxane coating formed by the hydrolysis and condensation of tetraethyl orthosilicate, coupled with low surface activity of the underlying basalt fibers, results in insufficient bonding with the organic matrices of graphene, polyethylene resin, and phenolic resin. This leads to fiber agglomeration and delamination within the matrix, creating numerous interfacial voids and weak points. Consequently, the pipeline's pressure resistance decreases, failing to meet the load-bearing and vibration resistance requirements of large ship pipelines. Pipeline rupture is highly likely. Lacking both the thermal stability protection of the siloxane coating and the flame-retardant carbon layer of ammonium polyphosphate, the high-temperature resistance of the basalt fibers alone is insufficient. The pipeline's ability to withstand temperature drops and its limiting oxygen index decreases, classifying it as a flammable material. In the confined space of a ship, it will burn rapidly when exposed to high temperatures or open flames, and has no smoke suppression or fire-retardant effect, seriously threatening the safety of ship navigation. The surface of unmodified basalt fiber has no protective layer. In the humid and salt spray environment of a ship, the fiber is prone to hydrolysis and aging, and the peeling phenomenon from the resin matrix is ​​aggravated. Even if the basic pressure-holding, airtightness and hydrostatic pressure performance meet the standards, long-term use will lead to problems such as pipe wall leakage and structural loosening.

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing fire-resistant and flame-retardant basalt fiber pipes for large ships, characterized in that, Includes the following steps: Flame-retardant basalt composite fibers are fed into an oven for segmented drying. The first stage of drying involves raising the temperature from 20-30℃ to 85-90℃, followed by holding at 85-90℃ for 50-60 minutes. The second stage involves raising the temperature from 85-90℃ to 100-105℃, followed by holding at 100-105℃ for 85-95 minutes. The third stage involves raising the temperature from 100-105℃ to 110-120℃, followed by holding at 110-120℃ for 140-160 minutes to completely evaporate the moisture from the fiber surface. The fibers are then wound into a mesh to form a fiber reinforcement layer. Graphene, polyethylene resin, and phenolic resin are poured onto the fiber reinforcement layer using a forming extrusion device, extruded, and cured to obtain fire-retardant basalt fiber pipes for large ships.

2. The method for preparing a fire-resistant and flame-retardant basalt fiber pipe for large ships according to claim 1, characterized in that, The ratio of graphene, polyethylene resin and phenolic resin is 20-22g: 60-70g: 50-55g.

3. The method for preparing a fire-retardant basalt fiber pipe for large ships according to claim 1, characterized in that, The specific preparation steps of the flame-retardant basalt composite fiber are as follows: Basalt composite fibers, ammonium polyphosphate, and a 50-60% ethanol solution were added to a reactor. Under a nitrogen atmosphere, the mixture was stirred at 50-60℃ and 400-500 r / min for 30-40 min, heated to 80℃, and stirred for 4-5 h. The mixture was then filtered, and the filter cake was washed 2-4 times with deionized water to obtain flame-retardant basalt composite fibers.

4. The method for preparing a fire-resistant and flame-retardant basalt fiber pipe for large ships according to claim 3, characterized in that, The ratio of the basalt composite fiber, ammonium polyphosphate, and ethanol solution is 40-42g: 22-24g: 500-600mL.

5. The method for preparing a fire-resistant and flame-retardant basalt fiber pipe for large ships according to claim 1, characterized in that, The specific preparation steps of the basalt composite fiber are as follows: Basalt fiber, ethanol, deionized water and ammonia are added to a reaction vessel and stirred for 20-30 minutes at 20-25℃ and 500-600 r / min. Then, tetraethyl orthosilicate is added, and the mixture is heated to 40-50℃ and stirred for 2-3 hours. The mixture is then filtered, and the fiber is washed 2-4 times with deionized water and anhydrous ethanol, respectively. The fiber is then vacuum dried at 60-70℃ for 1-2 hours to obtain basalt composite fiber.

6. The method for preparing a fire-resistant and flame-retardant basalt fiber pipe for large ships according to claim 5, characterized in that, The ratio of basalt fiber, ethanol, deionized water, ammonia and tetraethyl orthosilicate is 50-60g: 600-700mL: 70-80mL: 35-40mL: 80-90mL.

7. The method for preparing a fire-resistant and flame-retardant basalt fiber pipe for large ships according to claim 5, characterized in that, The specific preparation steps of the basalt fiber are as follows: Pretreated basalt, a 3 mol / L hydrochloric acid solution, and 20-25% oxalic acid were added to a high-pressure reactor. The mixture was stirred at 200-220℃ and 500-600 rpm for 8-9 hours, then allowed to cool naturally to room temperature. After filtration, the filter cake was washed 2-4 times with deionized water and anhydrous ethanol, respectively. The product was then vacuum dried at 60-70℃ for 1-2 hours. The product was then frozen at -20℃ to solidify. After thawing, it was sonicated for 40-60 minutes, filtered, and the filter cake was washed 2-4 times with deionized water and anhydrous ethanol, respectively. The product was then vacuum dried at 60-70℃ for 1-2 hours and ground until fluffy to obtain basalt fibers.

8. The method for preparing a fire-retardant basalt fiber pipe for large ships according to claim 7, characterized in that, The ratio of the pretreated basalt, hydrochloric acid solution, and oxalic acid is 70-80g: 1-2L: 800-900mL.

9. A method for preparing a fire-resistant and flame-retardant basalt fiber pipe for large ships according to claim 7, characterized in that, The specific preparation steps for the pretreated basalt are as follows: Basalt and deionized water are added to a reaction vessel and stirred for 20-30 minutes at 20-25℃ and 500-600 r / min. The mixture is then allowed to stand and soak for 24-26 hours, allowing it to settle naturally. The upper suspension is then filtered, and the filter cake is washed 2-4 times with deionized water and anhydrous ethanol, respectively. The cake is then vacuum dried at 60-70℃ for 1-2 hours to obtain pretreated basalt. The ratio of flammable rock to deionized water is 80-90g: 800-900mL.

10. A fire-resistant and flame-retardant basalt fiber pipe for large ships, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.