A composition for preparing high-silica glass fibers, high-silica glass fibers and a preparation method thereof

Abstract

The present invention provides a composition for preparing high-silica glass fiber, high-silica glass fiber and a preparation method thereof, belonging to the technical field of glass fiber. The composition for preparing high-silica glass fiber comprises the following components in terms of weight percentage: 65-75% of SiO2, 15-25% of B2O3, 5-15% of Na2O, 0.5-3% of Al2O3, 0.2-1.5% of Fe2O3, and 0.5-3% of P2O5. By regulating the contents of various components in the raw materials for preparing glass fiber, the present invention improves the uniformity of the melted glass and the stability of the melting and wire-drawing process, and the obtained high-silica glass fiber has a high silica content and low cost, and is suitable for industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of glass fibers, and particularly relates to a composition for preparing high-silica glass fibers, high-silica glass fibers and a preparation method thereof. Background Art

[0002] High-silica glass fiber is a new high-tech inorganic material with a SiO2 content greater than 96%. Due to its low thermal conductivity, good resistance to high thermal shock, good corrosion resistance to compounds, corrosive minerals, and weakly alkaline molten alloys at high temperatures, and its ability to work continuously under high heat and strong radiation conditions, it is widely used in the fields of high-temperature heat insulation protection and wave transmission of aerospace vehicles, heat preservation protection materials, etc.

[0003] However, the existing high-silica glass fibers have the problem of poor stability during the melting and drawing process. Therefore, there is an urgent need to provide high-silica glass fibers with high stability during the melting and drawing process. Summary of the Invention

[0004] In view of one or more technical problems existing in the prior art, the present invention provides a composition for preparing high-silica glass fibers, high-silica glass fibers and a preparation method thereof. The composition provided by the present invention has high stability during the melting and drawing process, high fiber-forming efficiency and forming quality, and the prepared high-silica glass fibers have a high silica content and high strength, and can be used for industrial production.

[0005] In the first aspect of the present invention, there is provided a composition for preparing high-silica glass fibers, the composition comprising the following components in weight percentages: SiO2 65-75%, B2O3 15-25%, Na2O 5-15%, Al2O3 0.5-3%, Fe2O3 0.2-1.5%, P2O5 0.5-3%.

[0006] Preferably, the total content of B2O3 and P2O5 accounts for 18-25% of the total weight of the composition; preferably, the content ratio of P2O5 to B2O3 is 2-20%.

[0007] Preferably, the total content of Al2O3 and Fe2O3 accounts for 1-4.5% of the total weight of the composition; preferably, the content ratio of Fe2O3 to Al2O3 is 6-40%.

[0008] In the second aspect of the present invention, there is provided a preparation method of high-silica glass fibers, the preparation raw materials used comprising the composition described in the first aspect, and the preparation method comprising the following steps:

[0009] S1. Melting and drawing the composition to obtain glass fiber rovings;

[0010] S2. Acid-treat and thermally sinter the glass fiber rovings to obtain the high-silica glass fibers.

[0011] Preferably, the diameter of the glass fiber rovings is not greater than 11 μm.

[0012] Preferably, the acid treatment is to immerse the glass fiber rovings in an acidic solution;

[0013] The acidic solution is one of an acidic solution containing hydrochloric acid, an acidic solution containing nitric acid, and an acidic solution containing sulfuric acid; preferably, the acidic solution further contains SO4 2- , Mg 2+ , Ca 2+ , Fe 3+ , boric acid, sodium borate, or one or more of them;

[0014] Preferably, the mass ratio of the acidic solution to the glass fiber rovings is (80 - 150):1, preferably 100:1.

[0015] Preferably, the acidic solution containing hydrochloric acid further contains SO4 2- , Mg 2+ , Ca 2+ , Fe 3+ , boric acid, sodium borate, or one or more of them; preferably, the equivalent concentration of hydrochloric acid is 3 - 3.3 N; the concentration of SO4 2- is not greater than 150 mg / L, the concentration of Mg 2+ is not greater than 35 mg / L, the concentration of Ca 2+ is not greater than 400 mg / L, the concentration of Fe 3+ is not greater than 30 mg / L, the concentration of boric acid is not greater than 0.15 mol / L, and the concentration of sodium borate is not greater than 30 g / L;

[0016] The acidic solution containing nitric acid further contains SO4 2- , Mg 2+ , Ca 2+ , Fe 3+ , boric acid, sodium borate, or one or more of them; preferably, the equivalent concentration of nitric acid is 3 - 3.3 N; the concentration of SO4 2- is not greater than 150 mg / L, the concentration of Mg 2+ is not greater than 35 mg / L, the concentration of Ca 2+ is not greater than 400 mg / L, the concentration of Fe 3+ is not greater than 30 mg / L, the concentration of boric acid is not greater than 0.15 mol / L, and the concentration of sodium borate is not greater than 30 g / L;

[0017] The acidic solution containing sulfuric acid further contains Mg 2+, Ca 2+ , Fe 3+ , one or more of boric acid and sodium borate; preferably, the equivalent concentration of the sulfuric acid is 3 - 3.3N; Mg 2+ concentration is not more than 35 mg / L, Ca 2+ concentration is not more than 400 mg / L, Fe 3+ concentration is not more than 30 mg / L, the concentration of boric acid is not more than 0.15 mol / L, and the concentration of sodium borate is not more than 30 g / L.

[0018] Preferably, the temperature of the acid treatment is 95 - 100 °C, and the time is 1 - 2 h; more preferably, the temperature of the acid treatment is 98 - 100 °C, and the time of the acid treatment is 1.5 h.

[0019] Preferably, the temperature of the thermal sintering treatment is 680 - 780 °C, and the time is 0.5 - 1 h.

[0020] The present invention provides a high-silica glass fiber in the third aspect, which is prepared by using the preparation method described in the second aspect.

[0021] The present invention has at least the following beneficial effects compared with the prior art

[0022] By regulating the content of each component in the raw materials for preparing glass fibers, the present invention improves the uniformity of the melted glass and the stability of the melting and wire-drawing process, improves the fiber-forming efficiency and forming quality of the glass fiber roving, and further obtains a high-silica glass fiber with a high silica content, high strength and more excellent performance, which can be used in industrial production. Detailed Embodiments

[0023] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some but not all of the embodiments of the present invention. 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.

[0024] The present invention provides, in a first aspect, a composition for preparing high-silica glass fibers, the composition comprising the following components by weight fraction: SiO2 65-75% (for example, it can be 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74% or 75%), B2O3 15-25% (for example, it can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24% or 25%), Na2O 5-15% (for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%), Al2O3 0.5-3% (for example, it can be 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.5%, 2.6%, 2.8% or 3%), Fe2O3 0.2-1.5% (for example, it can be 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 1% or 1.2%), P2O5 0.5-3% (for example, it can be 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.5%, 2.6%, 2.8% or 3%). It should be noted that the composition of the present invention also includes inevitable other impurities of 0.2-2%.

[0025] By regulating the content of each component in the raw materials for preparing glass fibers, the present invention improves the uniformity of the melted glass and the stability of the melting and drawing process, enhances the fiber-forming efficiency and forming quality of the glass fiber rovings, and thus obtains high-silica glass fibers with a high silica content, high strength and more excellent properties, which can be used in industrial production.

[0026] SiO2 is the glass network framework and also the matrix of high-silica oxide retained after acid treatment. If the content of SiO2 is too high, it is not conducive to the melting of the glass and the forming of the glass fiber rovings. If the content of SiO2 is too low, it will lead to too low a yield of high-silica fibers after acid treatment and low production economy.

[0027] As a flux and network former, B2O3 can promote the melting of the glass and the forming of the glass fiber rovings. If the content of B2O3 is too high, it will cause high-temperature phase separation, which is not conducive to the melting of the glass and fiber forming, and is also prone to volatilization. If the content of B2O3 is too low, it will result in uneven quality of the melted glass, affect the forming efficiency of the glass fiber rovings, and is not conducive to the production of the glass fiber rovings.

[0028] Na2O is used as a flux to promote the melting of glass for glass fibers and the forming of glass fiber rovings. If the content of Na2O is too high, it will lead to increased erosion of refractory materials and at the same time increase the volatilization of sodium oxide, which is not conducive to the melting of glass and the forming of glass fiber rovings. If the content of Na2O is too low, it will cause serious phase separation of the glass melt, which will also affect the forming efficiency of glass fiber rovings and is not conducive to the production of glass fiber rovings.

[0029] Al2O3 is a network intermediate. Introducing a small amount of Al2O3, A1 3+ can capture non-bridging oxygen to form aluminum-oxygen tetrahedrons and enter the silicon-oxygen network, reconnect the broken network, make the glass structure tend to be compact, can reduce the phase separation and crystallization tendency of the glass, improve the high-temperature chemical homogeneity of the glass, significantly improve the glass quality, reduce flying filaments and broken ends, avoid interruption of fiber filaments, and improve the fiber-forming efficiency of glass fiber rovings. If the content of Al2O3 is too low, it will lead to serious high-temperature phase separation of the glass, which is not conducive to the melting of glass and the forming of fiber rovings. If the content of Al2O3 is too high, it will be difficult for Al2O3 to be filtered out by acid leaching, and glass fibers with a high silica content cannot be obtained after acid leaching.

[0030] The introduction of Fe2O3 helps the high-temperature melting of glass and can improve the melting performance of glass. If the content of Fe2O3 is too high, it will reduce the heat transmittance of the glass melt, which is not conducive to the high-temperature melting of glass and is also not conducive to the filtration of Fe2O3 by acid leaching. If the content of Fe2O3 is too low, the fluxing effect cannot be achieved, which will affect the forming efficiency of fiber rovings. In addition, controlling the content of Fe2O3 within the above range can ensure that the content of Fe2O3 in the fiber does not exceed 0.3% after acid leaching, which helps to improve the heat insulation performance of fiber products, reduce the heat transmittance of fiber products, and can meet the fields with higher requirements for high-temperature heat insulation, that is, it can achieve high-temperature resistance performance and can also increase the large temperature drop on the cold surface of the product.

[0031] P2O5 also acts as a network former. The introduction of a small amount of P2O5 can reduce the volatilization, phase separation and erosion of the glass melt, improve the glass melting, and is conducive to fiber formation. However, too high a content of P2O5 will cause phase separation, which is not conducive to the melting and forming of fibers. In addition, partially replacing B2O3 with P2O5 is beneficial to cost reduction, reducing boron volatilization, reducing brick erosion, reducing glass phase separation, and significantly improving the stability and yield of fiber-forming operations, achieving significant economic benefits.

[0032] The present invention controls the dosages of the components in the composition within the above ranges to improve the fiber-forming efficiency and forming quality of glass fiber rovings, so as to ensure that high-silica glass fibers with a high silica content, high strength and excellent performance can be obtained after the fiber rovings are subjected to acid treatment and heat sintering treatment.

[0033] According to some preferred embodiments, the total content of B2O3 and P2O5 accounts for 18-25% of the total weight of the composition (for example, it can be 18%, 19%, 20%, 21%, 22%, 23%, 24% or 25%); preferably, the content ratio of P2O5 to B2O3 is 2-20% (for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%);

[0034] In the present invention, both P2O5 and B2O3 are network formers. On the basis of satisfying that "the total content of B2O3 and P2O5 is 18-25%, and the content ratio of P2O5 to B2O3 is 2-20%", introducing a small amount of P2O5 can be immiscible with the silica main network body and does not affect the filtration during the acid treatment process. At the same time, it is beneficial to the stability of wire drawing, reduces volatilization and brick erosion, improves the operation stability, improves the efficiency of acid leaching, and reduces the production cost.

[0035] According to some preferred embodiments, the total content of Al2O3 and Fe2O3 accounts for 1-4.5% of the total weight of the composition (for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or 4.5%); preferably, the content ratio of Fe2O3 to Al2O3 is 6-40% (for example, it can be 6%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 34%, 35%, 38% or 40%).

[0036] In the present invention, both Al2O3 and Fe2O3 are trivalent metal oxides. On the basis of satisfying that "the total content of Al2O3 and Fe2O3 is 1-4.5%, and the content ratio of Fe2O3 to Al2O3 is 6-40%", introducing a small amount of Fe2O3, through the mixing of Fe2O3 and Al2O3, can improve the melting performance of the high-boron glass and the tightness of the glass network structure, reduce the phase separation between the main network body and the secondary network body, and is beneficial to fiber forming; at the same time, the fiber prepared contains a small amount of iron oxide, which is beneficial to reducing the heat permeability of the fiber.

[0037] The present invention can prepare glass fibers with different silica contents by controlling the component contents of the composition to meet different requirements.

[0038] If it is necessary to prepare glass fibers with a silica content of 96%, the preferred composition contains the following components in parts by weight: SiO2 65-75% (for example, it can be 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74% or 75%), B2O3 15-25% (for example, it can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24% or 25%), Na2O 5-15% (for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%), Al2O3 0.5-3% (for example, it can be 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.5%, 2.6%, 2.8% or 3%), Fe2O3 0.2-1.5% (for example, it can be 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4% or 1.5%), P2O5 0.5-3% (for example, it can be 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.5%, 2.6%, 2.8% or 3%); wherein, the total content of B2O3 and P2O5 accounts for 18-23% of the total weight of the composition (for example, it can be 18%, 19%, 20%, 21%, 22% or 23%), and the content ratio of P2O5 to B2O3 is 2-10% (for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%); the total content of Al2O3 and Fe2O3 accounts for 1-4.5% of the total weight of the composition (for example, it can be 1%, 1.2%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2% or 4.5%), and the content ratio of Fe2O3 to Al2O3 is 6-20% (for example, it can be 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%);

[0039] If it is necessary to prepare glass fibers with a silica content of 97%, the preferably adopted composition contains the following components in parts by weight: SiO2 65-75% (for example, it can be 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74% or 75%), B2O3 18-23% (for example, it can be 18%, 19%, 20%, 21%, 22% or 23%), Na2O 7-10% (for example, it can be 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%), Al2O3 0.5-2% (for example, it can be 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%), Fe2O3 0.2-1.2% (for example, it can be 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 0.9%, 1% or 1.2%), P2O5 0.5-2% (for example, it can be 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%); wherein, the total content of B2O3 and P2O5 accounts for 18-23% of the total weight of the composition (for example, it can be 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5% or 23%), and the content ratio of P2O5 to B2O3 is 2-10% (for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%); the total content of Al2O3 and Fe2O3 accounts for 1-3% of the total weight of the composition (for example, it can be 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.5%, 2.6%, 2.8% or 3%), and the content ratio of Fe2O3 to Al2O3 is 6-10% (for example, it can be 6%, 7%, 8%, 9% or 10%).

[0040] If it is necessary to prepare glass fibers with a silica content of 98%, the preferably used composition contains the following components in parts by weight: SiO2 65-75% (for example, it can be 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74% or 75%), B2O3 18-23% (for example, it can be 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5% or 23%), Na2O 7-10% (for example, it can be 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%), Al2O3 0.5-1.5% (for example, it can be 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4% or 1.5%), Fe2O3 0.2-0.8% (for example, it can be 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7% or 0.8%), P2O5 0.5-2% (for example, it can be 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%); wherein, the total content of B2O3 and P2O5 accounts for 18-23% of the total weight of the composition (for example, it can be 18%, 19%, 20%, 21%, 22% or 23%); the total content of Al2O3 and Fe2O3 accounts for 1-2% of the total weight of the composition (for example, it can be 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%).

[0041] If it is necessary to prepare glass fibers with a silica content of 99%, the preferably adopted composition contains the following components in parts by weight: SiO2 65-75% (for example, it can be 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74% or 75%), B2O3 18-23% (for example, it can be 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5% or 23%), Na2O 7-10% (for example, it can be 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%), Al2O3 0.5-1% (for example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%), Fe2O3 0.2-0.5% (for example, it can be 0.2%, 0.3%, 0.4% or 0.5%), P2O5 0.5-1% (for example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%); wherein, the total content of B2O3 and P2O5 accounts for 18-23% of the total weight of the composition (for example, it can be 18%, 19%, 20%, 21%, 22% or 23%); the total content of Al2O3 and Fe2O3 accounts for 0.7-1.2% of the total weight of the composition (for example, it can be 0.7%, 0.8%, 0.9%, 1%, 1.1% or 1.2%).

[0042] In the second aspect, the present invention provides a method for preparing high-silica glass fibers. The raw materials used for preparation include the composition described in the first aspect. The preparation method includes the following steps:

[0043] S1. Melting and drawing the composition to obtain raw glass fibers;

[0044] S2. Subjecting the raw glass fibers to acid treatment and heat sintering treatment to obtain the high-silica glass fibers.

[0045] It should be noted that the present invention can also twist the raw fibers into yarns and then perform acid treatment and heat sintering treatment; or weave the raw fibers into fabrics and then perform acid treatment and heat sintering treatment to obtain glass fiber fabrics.

[0046] The present invention adopts a raw material composition with low cost and improves the stability and efficiency of the melting and drawing process by regulating the content of each component in the composition, obtaining glass fibers with small diameter and high quality. After acid treatment and heat sintering treatment, high-silica glass fibers with high silica content, low cost and controllable quality are obtained; the preparation process of the high-silica glass fibers of the present invention has low cost, short time consumption, high efficiency and controllable quality.

[0047] According to some preferred embodiments, the diameter of the glass fiber rovings is not greater than 11 μm; under the same other conditions, the content of silicon dioxide in the obtained glass fiber is controlled by controlling the diameter of the glass fiber rovings; for example, to prepare a glass fiber with a silicon dioxide content of 96%, glass fiber rovings with a diameter not greater than 11 μm are preferred; to prepare a glass fiber with a silicon dioxide content of 97%, glass fiber rovings with a diameter not greater than 9 μm are preferred; to prepare a glass fiber with a silicon dioxide content of 98%, glass fiber rovings with a diameter not greater than 8 μm are preferred; to prepare a glass fiber with a silicon dioxide content of 99%, glass fiber rovings with a diameter not greater than 7 μm are preferred; if the diameter of the glass fiber rovings is too large, it is not conducive to increasing the content of silicon dioxide and will reduce the content of silicon dioxide in the final glass fiber.

[0048] According to some preferred embodiments, the acid treatment is to immerse the glass fiber rovings in an acidic solution;

[0049] The acidic solution is one of an acidic solution containing hydrochloric acid, an acidic solution containing nitric acid, and an acidic solution containing sulfuric acid; preferably, the acidic solution further contains SO4 2- 、Mg 2+ 、Ca 2+ 、Fe 3+ 、boric acid, sodium borate or one or more of them;

[0050] Preferably, the mass ratio of the acidic solution to the glass fiber rovings is (80 - 150):1 (for example, it can be 80:1, 90:1, 100:1, 110:1, 120:1, 130:1, 140:1 or 150:1), preferably 100:1; controlling the mass ratio of the acidic solution and the glass fiber rovings within the above range can ensure the efficiency of the acid treatment. Continuing to increase the amount of the acidic solution will not significantly improve the treatment efficiency, and too much acidic solution will increase the energy consumption of subsequent treatment.

[0051] According to some preferred embodiments, the temperature of the acid treatment is 95 - 100 °C (for example, it can be 95 °C, 96 °C, 97 °C, 98 °C, 99 °C or 100 °C), and the time is 1 - 2 h (for example, it can be 1 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h or 2 h); more preferably, the temperature of the acid treatment is 98 - 100 °C (for example, it can be 98 °C, 99 °C or 100 °C), and the time of the acid treatment is 1.5 h.

[0052] The present invention removes B2O3, Na2O, Al2O3, Fe2O3, P2O5 in the glass fiber rovings through acid treatment to increase the content of SiO2 in the fiber.

[0053] According to some preferred embodiments, the acidic solution containing hydrochloric acid further contains SO4 2- , Mg 2+ , Ca 2+ , Fe 3+ , boric acid, sodium borate, or one or more thereof; preferably, the equivalent concentration of the hydrochloric acid is 3 to 3.3 N (for example, it can be 3 N, 3.1 N, 3.2 N, or 3.3 N); the concentration of SO4 2- is not more than 150 mg / L, the concentration of Mg 2+ is not more than 35 mg / L, the concentration of Ca 2+ is not more than 400 mg / L, the concentration of Fe 3+ is not more than 30 mg / L, the concentration of boric acid is not more than 0.15 mol / L, and the concentration of sodium borate is not more than 30 g / L;

[0054] The acidic solution containing nitric acid further contains SO4 2- , Mg 2+ , Ca 2+ , Fe 3+ , boric acid, sodium borate, or one or more thereof; preferably, the equivalent concentration of the nitric acid is 3 to 3.3 N (for example, it can be 3 N, 3.1 N, 3.2 N, or 3.3 N); the concentration of SO4 2- is not more than 150 mg / L, the concentration of Mg 2+ is not more than 35 mg / L, the concentration of Ca 2+ is not more than 400 mg / L, the concentration of Fe 3+ is not more than 30 mg / L, the concentration of boric acid is not more than 0.15 mol / L, and the concentration of sodium borate is not more than 30 g / L;

[0055] The acidic solution containing sulfuric acid further contains Mg 2+ , Ca 2+ , Fe 3+ , boric acid, sodium borate, or one or more thereof; preferably, the equivalent concentration of the sulfuric acid is 3 to 3.3 N (for example, it can be 3 N, 3.1 N, 3.2 N, or 3.3 N); the concentration of Mg 2+ is not more than 35 mg / L, the concentration of Ca 2+ is not more than 400 mg / L, the concentration of Fe 3+ is not more than 30 mg / L, the concentration of boric acid is not more than 0.15 mol / L, and the concentration of sodium borate is not more than 30 g / L.

[0056] By controlling the concentration of impurity ions or compounds in the acidic solution within the above range, the present invention can improve the efficiency of the acid treatment process, help increase the silica content of the fiber product, control the acid treatment time within 2 h, and at the same time, the acid treatment process is controllable, time-consuming and efficient; if the ion concentration exceeds the above range, the acid treatment efficiency and effect will be reduced, and it is difficult to obtain glass fibers with a high silica content; under the same other conditions, compared with the method of directly using hydrochloric acid for acid treatment, the acid treatment method of the present invention can obtain glass fibers with a higher silica content in a shorter time, greatly reducing energy consumption and being suitable for industrial production.

[0057] After the acid treatment, the present invention further includes a water washing step. When the pH of the surface of the fiber roving is greater than 5, it can be determined that the water washing is completed.

[0058] According to some preferred embodiments, the temperature of the thermal sintering treatment is 680 - 780 °C (for example, it can be 680 °C, 690 °C, 700 °C, 710 °C, 720 °C, 730 °C, 740 °C, 750 °C, 760 °C, 770 °C or 780 °C), and the time is 0.5 - 1 h (for example, it can be 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h or 1 h). Thermal sintering of the acid-treated fibers can reshape them and repair the holes existing on the surface and inside of the fibers caused by the acid treatment, which can reduce the defects of the glass fibers, improve the mechanical properties of the glass fibers, and obtain glass fibers with no cracks and depressions on the surface and high strength; if the sintering temperature is too low, the defects on the surface and inside of the fibers cannot be repaired, and the obtained glass fibers have poor strength; if the sintering temperature is too high, the obtained glass fibers are brittle and have low strength.

[0059] In the third aspect, the present invention provides a high-silica glass fiber prepared by using the preparation method described in the second aspect.

[0060] The high-silica glass fiber provided by the present invention is obtained by melting, drawing, acid treatment, and thermal sintering treatment of the composition of the first aspect; this high-silica glass fiber has low cost, high stability in the melting and drawing process, short acid treatment process time (not exceeding 2 h), high silica content (above 96%, up to 99% at most), high strength (up to above 0.3 N / tex, more than 20% higher than ordinary high-silica products), good temperature resistance, stable product performance, and low time cost, and can be applied to industrial production.

[0061] In order to more clearly illustrate the technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with embodiments.

[0062] The materials and reagents in the present invention can all be directly purchased on the market or synthesized by oneself, and no specific models are limited.

[0063] Example 1

[0064] S1. Melting and drawing the raw material composition to obtain glass fiber rovings with a diameter of 7 μm;

[0065] S2. Immersing the glass fiber rovings in an acidic solution at 98 °C for 1.5 h; wherein, the equivalent concentration of hydrochloric acid in the acidic solution is 3 N, the concentration of SO4 2- is 85 mg / L, the concentration of Mg 2+ is 30 mg / L, the concentration of Ca 2+ is 330 mg / L, the concentration of Fe 3+ is 25 mg / L, the concentration of boric acid is 0.1 mol / L, and the concentration of sodium borate is 20 g / L;

[0066] S3. Washing the immersed glass fiber rovings with water and performing heat sintering treatment at 720 °C to obtain high-silica glass fibers.

[0067] The preparation methods of the glass fibers in Examples 2-14 and Example 1 are basically the same, and the differences are shown in Table 1.

[0068] Table 1

[0069]

[0070]

[0071] The preparation methods of the glass fibers in Examples 15-25 and Example 1 are basically the same, and the differences are shown in Table 2.

[0072] Table 2

[0073]

[0074]

[0075] It should be noted that "-" in Tables 1-2 indicates that the component is not added or the performance data cannot be measured. The smaller the fiber shrinkage rate in the sintered state, the better the heat resistance; it should be noted that "-" in Table 1 indicates that the component is not added or the performance data cannot be measured. The smaller the fiber shrinkage rate in the sintered state, the better the heat resistance; as can be seen from Table 1, the concentration of Fe 3+ is too high in Example 2, and the concentration of sodium borate is too high in Example 3. Compared with Example 1, the silica content, heat resistance performance, and fiber strength of the glass fibers obtained within the same acid treatment time are reduced, indicating that too high a concentration of impurity ions or compounds in the acidic solution will reduce the efficiency and effect of acid treatment. The acidic solution in Example 1 contains SO4 2- , Mg 2+ , Ca 2+ , Fe 3+, The acidic solutions of boric acid and sodium borate have the best acid treatment efficiency. In Examples 5-8, the types of impurity ions and compounds in the acidic solutions decrease in sequence, and the acid treatment efficiency also decreases, but they are all higher than that of Example 9 which directly uses hydrochloric acid. The comprehensive properties of the finally obtained glass fibers (silica content, temperature resistance and fiber strength) are also better than those of Example 9. It can be seen that controlling the concentrations of impurity ions and compounds in the acidic solution within a certain range can effectively improve the acid treatment efficiency and obtain glass fibers with more excellent comprehensive properties. Further, it can be known from Table 1 and Table 2 that as the diameter of the fiber roving increases, the silica content, temperature resistance and fiber strength of the obtained glass fibers all decrease. From Examples 15-19, it can be seen that if the diameter of the fiber roving is too large, the silica content and temperature resistance of the obtained glass fibers will decrease significantly, and the fiber strength cannot be measured, which cannot meet the use requirements. From Examples 1, 22 and 23, it can be seen that too high P2O5 content and too high content ratio of Fe2O3 to Al2O3 will increase the linear thermal shrinkage rate of the sintered glass fibers and the temperature resistance will decrease. From Examples 24-25, it can be seen that too high or too low sintering temperature will increase the linear thermal shrinkage rate of the sintered glass fibers and the temperature resistance will decrease.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing high-silica glass fiber, characterized in that, The preparation method comprises the following steps: S1. Melting and drawing the composition to obtain virgin glass fibers; the composition comprises the following components in terms of weight percentage: 65-75% of SiO2, 15-25% of B2O3, 5-15% of Na2O, 0.5-3% of Al2O3, 0.2-1.5% of Fe2O3, 0.5-3% of P2O5; the total content of B2O3 and P2O5 accounts for 18-25% of the total weight of the composition; the content ratio of P2O5 to B2O3 is 2-20%; the total content of Al2O3 and Fe2O3 accounts for 1-4.5% of the total weight of the composition; the content ratio of Fe2O3 to Al2O3 is 6-40%; S2. Subjecting the virgin glass fibers to acid treatment and thermal sintering treatment to obtain the high-silica glass fibers; The acid treatment is to immerse the virgin glass fibers in an acidic solution; The acidic solution is one of an acidic solution containing hydrochloric acid, an acidic solution containing nitric acid, and an acidic solution containing sulfuric acid; The acidic solution containing hydrochloric acid also contains SO4 2- , Mg 2+ , Ca 2+ , Fe 3+ , boric acid, sodium borate or one or more thereof; the equivalent concentration of the hydrochloric acid is 3 to 3.3 N; the concentration of SO4 2- is not more than 150 mg / L, the concentration of Mg 2+ is not more than 35 mg / L, the concentration of Ca 2 + is not more than 400 mg / L, the concentration of Fe 3+ is not more than 30 mg / L, the concentration of boric acid is not more than 0.15 mol / L, and the concentration of sodium borate is not more than 30 g / L; The acidic solution containing nitric acid further contains one or more of SO4 2- , Mg 2+ , Ca 2+ , Fe 3+ , boric acid, and sodium borate; the equivalent concentration of the nitric acid is 3 to 3.3 N; the concentration of SO4 2- is not greater than 150 mg / L, the concentration of Mg 2+ is not greater than 35 mg / L, the concentration of Ca 2 + is not greater than 400 mg / L, the concentration of Fe 3+ is not greater than 30 mg / L, the concentration of boric acid is not greater than 0.15 mol / L, and the concentration of sodium borate is not greater than 30 g / L; The acidic solution containing sulfuric acid further contains one or more of Mg 2+ , Ca 2+ , Fe 3+ , boric acid, and sodium borate; the normal concentration of sulfuric acid is 3 to 3.3 N; the concentration of Mg 2+ is not more than 35 mg / L, the concentration of Ca 2+ is not more than 400 mg / L, the concentration of Fe 3+ is not more than 30 mg / L, the concentration of boric acid is not more than 0.15 mol / L, and the concentration of sodium borate is not more than 30 g / L.

2. The preparation method according to claim 1, characterized in that, The diameter of the virgin glass fibers is not greater than 11 μm.

3. The preparation method according to claim 1, characterized in that, The mass ratio of the acidic solution to the virgin glass fibers is (80-150):

1.

4. The preparation method according to claim 3, wherein The mass ratio of the acidic solution to the virgin glass fibers is 100:

1.

5. The preparation method according to claim 1, characterized in that, The temperature of the acid treatment is 95-100 °C, and the time is 1-2 h.

6. The preparation method according to claim 5, characterized in that, The temperature of the acid treatment is 98-100 °C, and the time is 1.5 h.

7. The preparation method according to claim 1, wherein The temperature of the thermal sintering treatment is 680-780 °C, and the time is 0.5-1 h.

8. A high silica glass fiber, characterized in that, Prepared by using the preparation method according to any one of claims 1-7.

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