Boron-free glass wool and preparation method thereof

Abstract

The invention belongs to the technical field of glass wool preparation, and discloses boron-free glass wool and a preparation method. Raw materials of the boron-free glass wool comprise cullet, sodium carbonate, dolomite and aluminum oxide. The preparation method of the boron-free glass wool comprises the following steps: (1) melting a batch through a pure oxygen top combustion system and an electric boosting system to obtain molten glass; and (2) carrying out fibration, wool collection, curing and cutting on the molten glass to obtain the boron-free glass wool. In the preparation process of the boron-free glass wool, the melting efficiency and the melting quality of the glass can be improved, high-quality and uniform glass liquid is produced, then qualified glass wool is produced, and meanwhile, the energy consumption and the production cost are greatly reduced.

Description

Technical Field

[0001] The present application relates to the technical field of glass wool preparation, and in particular to a boron-free glass wool and a preparation method thereof. Background Art

[0002] Glass wool belongs to inorganic insulation materials and is an important member in the field of insulation materials. It not only has excellent properties such as non-combustibility, low thermal conductivity, and good chemical stability, but can also be compounded or deeply processed with other materials to expand the application field of products. Glass wool products have been increasingly widely used in industries such as construction, metallurgy, petroleum, chemical industry, national defense and military industry, and high-tech industries, playing an important role in the development of the national economy. With higher requirements for the hardness and compressive resistance of glass wool, the content of alumina introduced into the glass composition is getting higher and higher. Since the melting point of A12O3 is 2050℃, it is more difficult to melt aluminosilicate glass, and the required melting temperature is higher, which greatly increases the energy consumption cost. Two methods are usually used in the prior art. One is to increase the content of alkali metal oxides in the glass to reduce the high-temperature viscosity and melting temperature of the glass. The other is to install an electric melting auxiliary heating device at the bottom of the kiln, so that the glass liquid relies on the Joule heat effect and heats itself, not relying on the space temperature, which can increase the temperature of the glass liquid, improve the melting efficiency of the glass, and help save energy and reduce consumption. However, as the price of alkali metal oxide raw materials continues to rise and the price of borax is also high, how to further reduce the production cost of glass wool while ensuring that the quality of glass wool is not reduced is a technical problem that needs to be solved. Summary of the invention

[0003] In order to solve at least one of the above technical problems, a boron-free, alkali metal-content-reduced, low-cost glass wool and a preparation method thereof are developed. The present application provides a boron-free glass wool and a preparation method thereof.

[0004] On the one hand, the present application provides a boron-free glass wool, comprising the following raw materials in parts by weight: 70-85 parts of broken glass, 13-17 parts of soda ash, 4-8 parts of dolomite, and 2-3 parts of alumina.

[0005] By adopting the above-mentioned technical scheme, no borax is added to the raw materials of the glass wool in the present application, and the content of alkali metal oxides is reduced. By improving other aspects, glass wool that meets the quality requirements can be produced to achieve the effect of reducing the cost of raw materials. At the same time, not using borax is beneficial to the protection of the top of the kiln. B2O3 is easy to volatilize. The high-temperature B2O3 molecules that continuously volatilize during the melting process of the glass raw materials in the kiln will corrode the refractory material on the top of the kiln and affect the overall service life of the kiln.

[0006] Optionally, the chemical composition of the cullet is: SiO2 55-75wt%, Al2O3 10-22wt%, CaO 11-17wt%, MgO 0.8-2.5wt%, Na2O 0.5-3wt%, K2O 0.2-1.5wt%.

[0007] Optionally, the chemical composition of the dolomite is: MgO: 21-27wt%, CaCO3 65-75wt%, K2CO3 0.5-2.5wt%.

[0008] Preferably, the raw material of the boron-free glass wool also includes 2-3 parts by weight of aluminum nitride, and the weight of the aluminum nitride is 2-3 parts based on the total weight of the raw material of the boron-free glass wool, for example, 2 parts, 2.2 parts, 2.5 parts, 3 parts, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are equally applicable.

[0009] Preferably, the raw material of the boron-free glass wool also includes 0.1-0.6 parts by weight of niobium pentoxide microspheres, and the weight of the niobium pentoxide microspheres is 0.1-0.6 parts based on the total weight of the raw materials of the boron-free glass wool, for example, 0.1 parts, 0.15 parts, 0.22 parts, 0.35 parts, 0.4 parts, 0.55 parts, 0.6 parts, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are equally applicable. The preparation method of the niobium pentoxide microspheres is as follows: dissolving niobium pentoxide and a foaming agent in water to form a suspension, and atomizing and drying the suspension, calcining, and grinding the suspension to obtain the niobium pentoxide microspheres; wherein the weight ratio of the foaming agent, niobium pentoxide, and water is 0.1-0.3:1:25-100; wherein the atomizing and drying temperature is 200°C-300°C, and the atomizing and drying feed rate is 50mL / h-250mL / h; the calcining temperature is 450°C-650°C, and the insulation time is 2h-4h.

[0010] By adopting the above technical scheme, aluminum nitride and niobium pentoxide microspheres are added to the raw materials for preparing glass wool, so as to improve the overall resistivity and thermal conductivity of the raw materials. When electric melting and pure oxygen top firing in a kiln are used for heating, it is helpful to exert the Joule heating effect of the glass, generate heat by itself, and not rely on the space temperature. The temperature of the molten glass can be increased, the melting efficiency of the glass can be improved, the quality of the molten glass can be improved, and the energy consumption and production cost can be reduced. At the same time, the hardness and thermal expansion coefficient of the glass are also improved, and the stability of the molten glass is better.

[0011] Optionally, the particle size of the niobium pentoxide microspheres is 0.05-1um, such as 0.05um, 0.1um, 0.12um, 0.15um, 0.2um, 0.5um, 0.8um or 1um, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0012] Preferably, the weight ratio of Na2O to K2O in the raw material is 9-15:1. For example, the weight ratio of Na2O to K2O is 9:1, 10:1, 12:1 or 15:1, but is not limited to the listed ratios, and other ratios not listed within the ratio range are also applicable.

[0013] In a second aspect, the present application provides a method for preparing the above-mentioned boron-free glass wool, comprising the following steps: S1, mixing the weighed raw materials into a mixing mixer to obtain a batch material; S2, adding the batch material obtained in step S1 into a kiln, wherein a pure oxygen burner is provided at the top of the kiln, and an electric melting device is provided at the bottom of the kiln, and pure oxygen top combustion and electric melting are used in combination to heat and melt to obtain glass liquid, wherein the oxygen concentration in the pure oxygen burner is 92-99.6wt%; S3, introducing glass liquid into a centrifugal head with a flow rate of 0.5-4 T / h, fiberizing the glass liquid by centrifugal blowing to obtain glass fibers, spraying a binder onto the surface of the glass fibers, collecting the glass fibers, thermally curing, cooling, and cutting them to obtain the boron-free glass wool; Wherein, in step S2, the heat energy generated by the electric melting device is 15-33% of the total heat energy of the batch material during melting in the kiln.

[0014] In this application, pure oxygen top firing technology is adopted, that is, a pure oxygen burner is set on the top of the kiln, and the flame of the pure oxygen burner directly acts on the surface of the batch material and the glass, and the flame directly impacts the surface of the material pile, and the material melting speed is faster. At the same time, it also avoids the disadvantages of large heat loss and large damage to the kiln arch when using pure oxygen side firing.

[0015] The space inside the kiln is large, and there are many raw materials that need to be melted. It is difficult to melt them evenly using a single electric heating or gas heating. If the melting effect is not good, it will greatly affect the subsequent glass liquid drawing process, resulting in unstable drawing or poor uniformity of the drawn glass wool. This application uses natural gas pure oxygen top combustion and electric melting to heat the raw materials in the kiln at the same time. Natural gas pure oxygen top combustion ensures the effective melting of the raw materials, and the auxiliary heating of electric melting ensures the temperature of the black glass liquid at the bottom of the kiln. By selecting a specific ratio, the overall rationality of the temperature system is ensured.

[0016] Preferably, in step S2, after heating and melting are completed, the temperature of the glass liquid at the bottom of the furnace is 1200-1250°C; in step S3, when the glass liquid passes through a centrifugal head for fiberization, the temperature of the centrifugal head is 970-1000°C.

[0017] Optionally, the binder comprises phenolic resin, silicon powder and zircon sand in a weight ratio of 80-90:5-10:5-10; the amount of the binder is 5-10wt% of the amount of the glass fiber.

[0018] The preparation method of boron-free glass wool described in the present application can be used for the preparation of boron-containing glass wool, wherein the raw material of the boron-containing glass wool is the same weight of the raw material for preparing the boron-free glass wool, and in addition, 3-8 weight parts of B2O3 are added; in the preparation process of the boron-containing glass wool, in the step S2, after the heating and melting are completed, the temperature of the glass liquid at the bottom of the kiln is 1150-1200°C; in the step S3, when the glass liquid passes through the centrifugal head for fiberization, the temperature of the centrifugal head is 930-950°C.

[0019] In summary, the present invention includes at least one of the following beneficial technical effects: 1. The production process of glass wool in this application fully utilizes the Joule heat effect of glass by adopting the pure oxygen top-firing combustion of the burner at the top of the kiln and the electric melting heating system at the bottom of the kiln, so that it can generate heat by itself without relying on the space temperature. The temperature of the glass liquid can be made higher, thereby improving the melting efficiency and melting quality of the glass, producing high-quality and uniform glass liquid, and then producing qualified glass wool.

[0020] 2. In the present application, aluminum nitride and niobium pentoxide microspheres are added to the raw materials for preparing glass wool to increase the overall resistivity and thermal conductivity of the raw materials, thereby contributing to the Joule heating effect of the glass and reducing energy consumption and production costs. DETAILED DESCRIPTION

[0021] The present application is further described in detail below with reference to the embodiments.

[0022] The present application designs a boron-free glass wool, which includes the following raw materials in parts by weight: 70-85 parts of cullet, 13-17 parts of soda ash, 4-8 parts of dolomite, and 2-3 parts of alumina.

[0023] The chemical composition of the cullet is: SiO2 55-75wt%, Al2O3 10-22wt%, CaO 11-17wt%, MgO 0.8-2.5wt%, Na2O 0.5-3wt%, K2O 0.2-1.5wt%.

[0024] The chemical composition of the dolomite is: MgO: 21-27wt%, CaCO3 65-75wt%, K2CO3 0.5-2.5wt%.

[0025] The raw materials of the boron-free glass wool also include 2-3 parts by weight of aluminum nitride.

[0026] The raw materials of the boron-free glass wool also include 0.1-0.6 parts by weight of niobium pentoxide microspheres. The preparation method of the niobium pentoxide microspheres is as follows: dissolving niobium pentoxide and a foaming agent in water to form a suspension, and atomizing and drying the suspension, calcining, and grinding to obtain the niobium pentoxide microspheres; wherein the weight ratio of the foaming agent, niobium pentoxide powder and water is 0.1-0.3:1:25-100; wherein the atomizing and drying temperature is 200°C-300°C, and the atomizing and drying feed rate is 50mL / h-250mL / h; the calcining temperature is 450°C-650°C, and the insulation time is 2h-4h.

[0027] The boron-free glass wool of the present application is prepared by the following method, comprising the following steps: S1, mixing the weighed raw materials into a mixing mixer to obtain a batch material; S2, adding the batch material obtained in step S1 into a kiln, wherein a pure oxygen burner is provided at the top of the kiln, and an electric melting device is provided at the bottom of the kiln, and pure oxygen top combustion and electric melting are used in combination to heat and melt to obtain glass liquid, wherein the oxygen concentration in the pure oxygen burner is 92-99.6wt%; S3, introducing glass liquid into a centrifugal head with a flow rate of 0.5-4 T / h, fiberizing the glass liquid by centrifugal blowing to obtain glass fibers, spraying a binder onto the surface of the glass fibers, collecting the glass fibers, thermally curing, cooling, and cutting them to obtain the boron-free glass wool; Wherein, in the step S2, during the process of the batch material being melted into glass liquid in the furnace, the heat energy generated by the electric melting device accounts for 15-33% of the total heat energy of the process.

[0028] In the step S2, after the heating and melting is completed, the temperature of the glass liquid at the bottom of the furnace is 1200-1250°C; in the step S3, when the glass liquid passes through the centrifugal head for fiberization, the temperature of the centrifugal head is 970-1000°C.

[0029] The technical problem solved by this application is that as the requirements for the hardness and compressive resistance of glass wool become higher, the content of alumina introduced into the glass component becomes higher and higher. Since the melting point of A12O3 is 2050°C, it is more difficult to melt aluminosilicate glass, the melting temperature required is higher, and the energy consumption cost increases significantly. As the price of alkali metal oxide raw materials continues to rise, and the price of borax is also high, how to further reduce the production cost of glass wool while ensuring that the quality of glass wool is not reduced is a technical problem that needs to be solved. On the one hand, this application uses the pure oxygen top burning combustion of the kiln top burner and the electric melting heating system at the bottom of the kiln in the production process of glass wool. On the other hand, aluminum nitride and niobium pentoxide microspheres are added to the raw materials for preparing glass wool to improve the overall resistivity and thermal conductivity of the raw materials, give full play to the Joule heating effect of glass, reduce energy consumption and production costs, produce high-quality and uniform glass liquid, and then produce qualified glass wool.

[0030] The sources of raw materials in the examples of this application are as follows: Aluminum nitride, Guangzhou Huao Chemical Co., Ltd.; Niobium pentoxide powder, Guangzhou Nano Chemical Technology Co., Ltd.; Dolomite, Jiangxi Haiyuan Chemical Co., Ltd.

[0031] Examples 1-10 Examples 1-10 are boron-free glass wool prepared with different raw material ratios, and the specific ratios are shown in Table 1.

[0032] Table 1 In Examples 1-10, the weight ratio of Na2O to K2O in the raw material is 11:1.

[0033] The preparation method of the niobium pentoxide microspheres in Examples 1-10 is as follows: dissolving niobium pentoxide and a foaming agent in water to form a suspension, atomizing and drying the suspension, and calcining the suspension to obtain the niobium pentoxide microspheres; wherein the weight ratio of the foaming agent, niobium pentoxide powder and water is 0.2:1:50; wherein the atomizing and drying temperature is 250°C, and the atomizing and drying feed rate is 200mL / h; the calcining temperature is 500°C, and the holding time is 3h.

[0034] The particle size of the niobium pentoxide microspheres in Examples 1-10 is 0.2 um.

[0035] The preparation process of Examples 1-10 is: S1, mixing the weighed raw materials into a mixing mixer to obtain a batch material; S2. Add the batch material obtained in step S1 into a kiln, wherein a pure oxygen burner is provided at the top of the kiln, and an electric melting device is provided at the bottom of the kiln, and pure oxygen top combustion and electric melting are used in combination for heating and melting to obtain molten glass, wherein the oxygen concentration in the pure oxygen burner is 95.5wt%; wherein after the heating and melting is completed, the temperature of the molten glass at the bottom of the kiln is controlled to be 1240°C; during the process of the batch material being melted into molten glass in the kiln, the heat energy generated by the electric melting device accounts for 26% of the total heat energy of the batch material during the melting process in the kiln.

[0036] S3. Introduce the glass liquid into a centrifugal head, control the temperature of the centrifugal head to 980°C, and the flow rate of the centrifugal head to 1 T / h, fiberize the glass liquid by centrifugal blowing to obtain glass fiber, spray a binder onto the surface of the glass fiber, collect the glass fiber, thermally cure, cool, and cut it to obtain the boron-free glass wool; wherein the binder is phenolic resin, silicon micropowder, and zircon sand in a weight ratio of 85:6:8, and the amount of the binder is 8wt% of the amount of the glass fiber.

[0037] Examples 11-12 Example 11 is based on Example 8, with the difference that in step S2 of Example 11, after heating and melting are completed, the temperature of the glass liquid at the bottom of the kiln is controlled to be 1200°C.

[0038] Example 11 is based on Example 8, with the difference that in step S2 of Example 12, after heating and melting are completed, the temperature of the glass liquid at the bottom of the kiln is controlled to be 1300°C.

[0039] Examples 13-14 Example 13 is based on Example 8, with the difference that in Example 13, during the process of melting the batch materials into molten glass in the kiln in step S2, the heat energy generated by the electric melting device accounts for 15% of the total heat energy of the melting process.

[0040] Example 14 is based on Example 8, with the difference that in Example 14, during the process of melting the batch materials into molten glass in the kiln in step S2, the heat energy generated by the electric melting device accounts for 33% of the total heat energy of the melting process.

[0041] Comparative Examples 1-3 Comparative Example 1 is based on Example 3, except that the amount of alkali metal oxide used in Comparative Example 1 is changed to 22 kg.

[0042] Comparative Example 2 is based on Example 3, except that 4 kg of borax is added to Comparative Example 2, and the amount of alkali metal oxide is changed to 22 kg.

[0043] Comparative Example 3 is based on Example 8, with the difference that the pure oxygen burner in Comparative Example 3 is arranged at the breast wall of the kiln, that is, pure oxygen side burning is used for heating.

[0044] Comparative Example 4 is based on Example 8, with the difference that in Comparative Example 4, during the process of melting the batch material into molten glass in the kiln in step S2, the heat energy generated by the electric melting device accounts for 40% of the total heat energy of the melting process.

[0045] Performance Testing 1. Calculate the preparation costs of Examples 1-14 and Comparative Examples 1-3, and calculate the total cost of preparing one ton of glass wool, including raw material cost and energy consumption cost.

[0046] 2. The tensile strength of the glass wool prepared in Examples 1-16 and Comparative Examples 1-3 was measured according to standard ASTM-D2343, MPa.

[0047] 3. The elastic modulus of the glass wool prepared in Examples 1-16 and Comparative Examples 1-3 was measured according to standard ASTM-D2343, GPa.

[0048] 4. The thermal expansion coefficients at 20-400°C of the glass wool prepared in Examples 1-16 and Comparative Examples 1-3 were determined according to standard ASTM-D696.

[0049] 5. The thermal conductivity of the glass wool prepared in Examples 1-16 and Comparative Examples 1-3 was measured using a thermal constant analyzer (Hot Disk TPS2500).

[0050] 6. Use an ultra-high resistance micro-current measuring instrument to measure the resistivity of the glass liquid at 1200°C in Examples 1-16 and Comparative Examples 1-3.

[0051] The test results are shown in Tables 1 and 2 respectively.

[0052] Table 1 Table 2 By analyzing the data in Table 1 and Table 2, it can be concluded that the boron-free glass wool prepared in Example 8 reduces the preparation cost per ton to the minimum under the premise of ensuring the quality of the glass wool. Therefore, by adding aluminum nitride and niobium pentoxide microspheres to the raw materials for preparing glass wool, the overall resistivity and thermal conductivity of the raw materials are improved, and at the same time, the pure oxygen top burning combustion of the burner at the top of the kiln and the electric flux heating system at the bottom of the kiln are used to help reduce energy consumption and production costs.

[0053] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A boron-free glass wool, characterized in that: The invention comprises the following raw materials in parts by weight: 70-85 parts of broken glass, 13-17 parts of soda ash, 5-7 parts of borax, 4-8 parts of dolomite, and 2-3 parts of alumina.

2. The boron-free glass wool according to claim 1, characterized in that: The chemical composition of the cullet is: SiO2 55-75wt%, Al2O3 12.5-22wt%, CaO 11-17wt%, MgO 0.8-2.5wt%, Na2O 0.5-3wt%, K2O 0.2-0.5wt%.

3. The boron-free glass wool according to claim 1, characterized in that: The chemical composition of the dolomite is: MgO: 21-27wt%, CaCO3 65-75wt%, K2CO3 0.5-2.5wt%.

4. The boron-free glass wool according to claim 1, characterized in that: The raw materials of the boron-free glass wool also include 2-3 parts by weight of aluminum nitride.

5. The boron-free glass wool according to claim 1, characterized in that: The raw materials of the boron-free glass wool also include 0.1-0.6 parts by weight of niobium pentoxide microspheres. The preparation method of the niobium pentoxide microspheres is as follows: dissolving niobium pentoxide and a foaming agent in water to form a suspension, and atomizing and drying the suspension, calcining, and grinding to obtain the niobium pentoxide microspheres; wherein the weight ratio of the foaming agent, niobium pentoxide, and water is 0.1-0.3:1:25-100; the temperature of the atomizing and drying is 200°C-300°C, and the feed rate of the atomizing and drying is 50mL / h-250mL / h; the temperature of the calcining is 450°C-650°C, and the insulation time is 2h-4h.

6. The boron-free glass wool according to claim 3, characterized in that: The particle size of the niobium pentoxide microspheres is 0.05-1um.

7. The boron-free glass wool according to claim 1 or 5, characterized in that: The weight ratio of Na2O to K2O in the raw material is 9-15:

1.

8. A method for preparing the boron-free glass wool according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, mixing the weighed raw materials into a mixing mixer to obtain a batch material; S2, adding the batch material obtained in step S1 into a kiln, wherein a pure oxygen burner is provided at the top of the kiln, and an electric fluxing device is provided at the bottom of the kiln, and the pure oxygen top combustion system and the electric fluxing system are used in combination to heat and melt the batch material to obtain glass liquid, wherein the oxygen concentration in the pure oxygen burner is 92-99.6wt%; S3, introducing glass liquid into a centrifugal head with a flow rate of 0.5-4 T / h, fiberizing the glass liquid by centrifugal blowing to obtain glass fibers, spraying a binder onto the surface of the glass fibers, collecting the glass fibers, thermally curing, cooling, and cutting them to obtain the boron-free glass wool; Wherein, in the step S2, the heat energy generated by the electric melting device is 15-33% of the total heat energy of the batch material during the melting process in the kiln.

9. The method for preparing boron-free glass wool according to claim 8, characterized in that: In the step S2, after the heating and melting is completed, the temperature of the glass liquid at the bottom of the furnace is 1200-1250°C; in the step S3, when the glass liquid passes through the centrifugal head for fiberization, the temperature of the centrifugal head is 970-1000°C.

10. The method for preparing boron-free glass wool according to claim 8, characterized in that: The binder comprises phenolic resin, silicon powder and zircon sand in a weight ratio of 80-90:5-10:5-10; the amount of the binder is 5-10wt% of the amount of the glass fiber.

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