Porous glass beads and application thereof in purification of alkali-free glass fiber drawing environment

Abstract

The invention provides a porous glass bead and application thereof in purification of an alkali-free glass fiber drawing environment. The body chemical components of the porous glass beads are the same as the chemical components of molten glass used for drawing alkali-free glass fibers, and the surfaces of the porous glass beads are provided with nanoscale or micron-nano composite porous structures formed through chemical corrosion, and the porous glass beads are used for adsorbing gaseous volatile matters volatilized from the molten glass in the drawing process of the alkali-free glass fibers and recovering the gaseous volatile matters in situ. The technical problem to be solved is how to use porous glass beads to purify an alkali-free glass fiber drawing environment, so that the porous glass beads not only can efficiently capture boron and fluorine volatile matters to control generation of glass fiber fog, but also can avoid secondary pollution caused by introduction of heterogeneous impurities. Meanwhile, in-situ recovery of volatile matters can be realized, the volatile matters are fed back to the molten glass again to maintain component uniformity, and the preparation process is simple, controllable in cost and suitable for industrial large-scale application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of glass fiber manufacturing and functional materials, and particularly relates to porous glass microbeads and application of the porous glass microbeads in environment purification in alkali-free glass fiber drawing. BACKGROUND

[0002] In the process of drawing alkali-free glass (E-glass) fibers, boron oxide (B2O3) and fluorides (such as CaF2) contained in the glass liquid volatilize in large quantities at high temperatures. During the rising process, these gaseous volatiles condense into micron or sub-micron dust when encountering the furnace top, electrode and furnace wall with lower temperature, which is commonly known as "glass fiber mist". This can cause a series of serious problems: 1) the condensation nuclei fall back to the glass liquid surface or the newly born fiber, forming defect points, resulting in an increase in fiber breakage rate and a decrease in product yield; 2) the volatiles condense on the surface of the electrode, corrode the electrode and form scale on the furnace top and refractory material, forcing the production to be interrupted for cleaning and increasing the maintenance cost; 3) selective volatilization causes differences in the surface layer and the main body of the glass liquid, affecting the stability of the glass viscosity and destroying the stability of the drawing process.

[0003] The industry has considered using heterogeneous adsorbents, such as porous ceramics, for adsorption, but due to the risk of introducing secondary pollution caused by the falling of the heterogeneous impurities, it is impossible to apply, so there has been a long-term key technical bias in the field of alkali-free glass fiber drawing: in order to avoid the introduction of secondary pollution caused by heterogeneous impurities into the glass liquid, the industry generally prohibits the addition of any functional materials into the furnace. This bias has led the existing technology to a passive treatment dilemma.

[0004] At present, the commonly known solution is to strengthen the sealing of the furnace body and forcibly exhaust. However, this method can only exhaust part of the volatiles outside the furnace, cannot solve the problem of condensation pollution in the furnace, and will cause loss of effective components and environmental pollution. There are also attempts to use refractory material baffles to physically block, but the effect is limited, and the baffles themselves can also become scale points. SUMMARY

[0005] The main purpose of the present application is to provide porous glass microbeads and application of the porous glass microbeads in environment purification in alkali-free glass fiber drawing. The technical problem to be solved is how to apply the porous glass microbeads to purify the environment in alkali-free glass fiber drawing, so that it can not only capture boron and fluorine volatiles efficiently to control the generation of glass fiber mist, but also avoid the introduction of heterogeneous impurities to cause secondary pollution; at the same time, the volatiles can be recovered in situ and fed back to the glass liquid to maintain the uniformity of the components, and the preparation process is simple, the cost is controllable, and it is suitable for industrial large-scale application.

[0006] The objective of this invention and the technical problem it solves are achieved by the following technical solution. According to this invention, a porous glass microsphere for environmental purification using alkali-free glass fiber drawing is provided. The bulk chemical composition of the porous glass microsphere is the same as that of the molten glass used in the drawing of alkali-free glass fiber. Furthermore, the surface of the porous glass microsphere has a nanoscale or micron-nano composite porous structure formed through chemical etching. The porous glass microsphere is used to adsorb and in-situ recover gaseous volatiles volatilized from the molten glass during the alkali-free glass fiber drawing process.

[0007] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0008] Preferably, the porous glass microspheres have a particle size of 1-2 mm and a BET specific surface area of ​​8-36 m² / g.

[0009] The objective of this invention and the technical problem it solves are achieved through the following technical solution. The application of porous glass microspheres in the environmental purification process of alkali-free glass fiber drawing, according to this invention, includes the following steps: S1. The porous glass microspheres are placed above the molten glass in the drawing furnace in the diffusion path of the gaseous volatiles. The chemical composition of the porous glass microspheres is the same as that of the molten glass used to draw alkali-free glass fibers, and the surface of the porous glass microspheres has a nanoscale or micron-nano composite porous structure formed by chemical etching. S2 porous glass microspheres capture gaseous volatiles volatilized from the molten glass to a preset standard through their porous structure; The porous glass microspheres, after adsorbing gaseous volatiles in S3, are poured into the melting furnace to melt; the molten glass, after absorbing gaseous volatiles, is transported to the drawing furnace, where it is drawn into fibers by the drawing machine through the lower baffle plate.

[0010] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0011] Preferably, in the application, the preset standard is selected from at least one of adsorption time, microbead weight increment, and BET surface area decrease threshold.

[0012] Preferably, in the aforementioned application, the adsorption time for each batch of porous glass microspheres is 24-48 hours, based on the furnace running time.

[0013] Preferably, in the application described, the gaseous volatiles captured by the porous glass microspheres include boron- and / or fluorine-containing substances.

[0014] Preferably, in the aforementioned application, the porous glass microspheres have a particle size of 1-2 mm and a BET specific surface area of ​​8-36 m² / g.

[0015] Preferably, in the application, the porous glass microspheres are placed above the molten glass in the drawing furnace along the diffusion path of the gaseous volatiles by suspending a high-temperature resistant sieve-type material receiving tank in a region above the molten glass in the drawing furnace where the temperature is lower than the softening point of the glass microspheres; the porous glass microspheres are disposed in the material receiving tank.

[0016] Preferably, in the aforementioned application, the chemical corrosion includes the following steps: S1 involves ultrasonically cleaning and drying alkali-free solid glass microspheres with a particle size of 1.0~2.0 mm, then placing them in an etching solution under stirring conditions and etching them under preset conditions. S2 filtration, washing until neutral, drying, to obtain porous glass microspheres.

[0017] Preferably, in the application, the corrosive solution is a hydrochloric acid, nitric acid, or sodium hydroxide solution with a concentration of 0.8~2.5mol / L; the stirring speed is 250~350rpm; and the preset conditions are as follows: solid-liquid ratio of 1g:4.5~5.5ml, reaction temperature of 50~80℃, and reaction time of 30~120min.

[0018] By employing the above technical solution, the porous glass microspheres proposed in this invention and their application in alkali-free glass fiber drawing for environmental purification have at least the following beneficial effects: The core innovation of this invention, which proposes porous glass microspheres and their application in environmental purification during the drawing of alkali-free glass fibers, lies in breaking the industry's technical prejudice against introducing heterogeneous materials. By selecting alkali-free glass microspheres that are completely homogeneous with the glass melt used to draw alkali-free glass fibers as the substrate, and preparing a porous structure through chemical etching, it avoids the risk of secondary pollution from heterogeneous materials and achieves active adsorption and in-situ recovery of volatile substances. Ultimately, it upgrades the industry from passive pollution discharge to active closed-loop purification, filling the technical gap in safe adsorption and in-situ recovery in this field. Specifically, its core feature is that the chemical composition of the porous glass microspheres is consistent with that of the molten glass used for drawing. This ensures that when the porous glass microspheres adsorb volatiles and melt back into the furnace, no foreign impurities are introduced, fundamentally eliminating secondary pollution. Simultaneously, the captured effective volatile components, such as boron and fluorine, are returned to the molten glass, maintaining the uniformity of the molten glass's chemical composition and ensuring the stability of the fiber drawing process. Furthermore, relying on the nanoscale or micron-nano composite porous structure formed by chemical etching on its surface, the BET specific surface area of ​​the porous glass microspheres is increased to 8~36 m² / g, significantly increasing its contact area with gaseous volatiles. This significantly improves the volatile capture efficiency, effectively reducing the formation of glass fiber fog and lowering fiber density. This invention improves product yield by reducing breakage rate. It utilizes a process where porous glass microspheres are placed along the diffusion path of volatiles to capture gaseous volatiles, which are then melted back into the molten glass after adsorption saturation. This proactively intercepts volatiles at the source of pollution, reducing condensation and scaling on furnace tops, electrodes, and refractory material surfaces. This extends equipment lifespan and continuous production cycles, while lowering maintenance and cleaning costs. Furthermore, the raw materials for preparing porous glass microspheres are readily available, and the chemical etching process is mild and controllable (the type, concentration, reaction temperature, and time of the etching solution are clearly adjustable). The application is simple, using a high-temperature resistant sieve-filled tray and a pre-defined standard to determine the adsorption state. This approach is suitable for large-scale industrial production, achieving a balance between environmental and economic benefits.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Detailed Implementation

[0020] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following detailed description, in conjunction with preferred embodiments, details the specific implementation methods and effects of a porous glass microsphere proposed according to the present invention and its application in environmental purification using alkali-free glass fiber drawing. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, the results of one or more embodiments can be combined in any suitable manner. These embodiments are provided to make the invention thorough and complete, and to fully express the scope of the invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​described in these embodiments should be interpreted as merely exemplary and not as limiting.

[0021] This invention proposes a porous glass microsphere for environmental purification in alkali-free glass fiber drawing and its application in this process. The porous glass microsphere is placed above the molten glass in the drawing furnace, along the diffusion path of gaseous volatiles. The microsphere's bulk chemical composition is the same as that of the molten glass used in alkali-free glass fiber drawing, and its surface has a nanoscale or micron-nano composite porous structure formed by chemical etching. The porous glass microsphere is used to adsorb and recover gaseous volatiles volatilized from the molten glass during the alkali-free glass fiber drawing process. Through its porous structure, it captures the gaseous volatiles volatilized from the molten glass to a preset standard. After adsorbing the gaseous volatiles, the porous glass microsphere melts and returns to the drawing furnace for fiber drawing.

[0022] In the above technical solution, the solid microspheres are selected by using solid microspheres with the same chemical composition as the glass melt used to draw alkali-free glass fibers, while controlling the microsphere particle size to be 1.0-2.0 mm, to ensure seamless fusion with the glass melt after subsequent melting.

[0023] The above technical solution controls the porous structure of the microspheres through a chemical etching process. The etchant can be selected from 0.5-3.0 mol / L hydrochloric acid, nitric acid, or 0.5-2.5 mol / L sodium hydroxide solution. The reaction is carried out at 50-80℃ for 20-120 minutes, with a stirring rate controlled at approximately 300 rpm, preferably 250-350 rpm. This ultimately forms a nanoscale or micron-nano composite porous structure. This optimized process allows the BET specific surface area of ​​the microspheres to be controlled at ≥8 m² / g, preferably 8-36 m² / g. Specific etching process parameters can be determined by comprehensively considering the surface area and microsphere strength requirements based on the application scenario, thus enabling the personalized preparation of porous glass microspheres suitable for specific applications. To balance the overall performance of the porous glass microspheres, this invention preferably uses a 0.8-2.5 mol / L hydrochloric acid, nitric acid, or sodium hydroxide solution as the etching solution. The solid-liquid ratio of the microspheres to the etching solution is 1 g: 4.5-5.5 ml.

[0024] In the above technical solution, the solid microspheres are ultrasonically cleaned by first ultrasonically cleaning with anhydrous ethanol for 10-20 minutes, and then ultrasonically cleaning with deionized water for 10-20 minutes. The drying temperature is 100-120℃, and the drying time is 1.5-2.5 hours. In some specific embodiments of the present invention, the solid microspheres are first ultrasonically cleaned with anhydrous ethanol for about 15 minutes, then ultrasonically cleaned with deionized water for about 15 minutes, and dried at 110℃ for about 2 hours to ensure their cleanliness. After the etching process, they are vacuum filtered, and the microspheres are repeatedly washed with a large amount of deionized water until the pH test is neutral (pH=7), and then dried at 110℃ for about 2 hours to ensure that the porous glass microspheres are free of residual impurities.

[0025] In the above technical solution, the porous microspheres are placed about 10-20cm above the molten glass in the drawing furnace, which can cover the main diffusion path of gaseous volatiles, such as the rising channel from the middle of the furnace to the top of the furnace, so as to avoid direct contact with the molten glass and affect the stability of the liquid surface.

[0026] In the above technical solution, porous microspheres are loaded in a high-temperature resistant alloy mesh basket (the mesh pore size is between 0.5 and 1 times the diameter of the microspheres) and suspended above the drawing furnace in an area where the temperature is lower than the softening point of the glass microspheres, ensuring that the airflow can pass through the microsphere layer. In some specific embodiments of the present invention, it is preferable to lay the porous glass microspheres into an adsorption layer with a thickness of 10-20 mm to ensure that the volatiles are in full contact with the microspheres. In some specific embodiments of the present invention, this thickness of adsorption layer generally requires laying a porous glass microsphere layer weighing about 200-400 g.

[0027] In some specific embodiments of the present invention, it is preferred that the circular furnace body is evenly distributed along the circumference, and the square furnace body is laid out in a grid pattern, focusing on covering the periphery of the electrodes and the high-concentration area on the furnace top.

[0028] In the above technical solution, the preset standard for the adsorption of gaseous volatiles by porous microspheres is selected from at least one of adsorption time, microsphere weight increment, and BET specific surface area reduction threshold; preferably, the condensation amount of volatiles in the furnace is used as the core indicator, with the goal of achieving a capture and recovery rate of volatiles (such as boron oxides and fluorides) of 30-60%, thereby effectively alleviating the unevenness of glass melt viscosity and surface tension, overcoming problems such as uneven fiber diameter, broken fibers, and flyaways caused by composition fluctuations, and ensuring that the fluctuation rate of single fiber diameter is reduced by 40% to 60%; the microsphere adsorption saturation standard is preferably a specific surface area reduction to less than 50% of the initial value, or based on the furnace running time, the adsorption time for each batch of porous glass microspheres is 24-48 hours, and the specific duration can be adjusted according to the production intensity; in some specific embodiments of the present invention, the microsphere status is checked periodically through the furnace observation window, combined with fiber product yield and equipment maintenance records, to help determine whether the adsorption effect meets the standard, thereby replenishing or replacing microspheres in a timely manner.

[0029] In the above technical solution, once the microspheres reach adsorption saturation, the receiving tank is removed, and the saturated porous glass microspheres are poured into the melting furnace for melting. Since the molten microspheres are completely homogeneous with the molten glass in the furnace, the adsorbed volatile components such as boron and fluorine can be simultaneously returned to the molten glass to replenish the effective components lost due to volatilization. After the porous microspheres are melted and recovered, new porous microspheres are added according to the remaining amount of microspheres in the furnace to maintain the continuity of the adsorption effect. The molten glass that has absorbed gaseous volatiles in the melting furnace is then transported to the drawing furnace, where fibers are drawn by the drawing machine through the lower baffle plate, completing the in-situ recovery and replenishment of gaseous volatiles.

[0030] In the above technical solution, the key to the efficient capture of gaseous volatiles lies in the synergy of physical interception and condensation adsorption of the porous structure of microspheres. The nanoscale or micron-nano composite channels on the surface of the microspheres enhance the physical adsorption capacity through a large specific surface area. On the other hand, the channels form local low-temperature zones, which cause high-temperature gaseous volatiles, such as boron oxide and fluorides, to condense rapidly into liquid or solid states and be firmly locked in the channels. At the same time, the present invention lays the microspheres along the diffusion path of the volatiles, forming an adsorption barrier and preventing the volatiles from rising directly to low-temperature surfaces such as the furnace top and electrodes. The capture efficiency is greatly improved compared with traditional methods.

[0031] In the above technical solution, the porous microspheres have the same chemical composition as the molten glass. After melting, they return to the molten glass without introducing any foreign elements, thus completely eliminating secondary pollution. The boron, fluorine and other components recovered by them return directly to the molten glass, which makes up for the difference between the surface layer and the main components caused by selective volatilization, maintains the stability of the molten glass viscosity, and ensures that the drawing process parameters do not deviate.

[0032] In the above technical solution, gaseous volatiles are captured in advance by porous microspheres, which can significantly reduce the probability of scale formation on the furnace top and electrode erosion, avoid production interruptions caused by scale removal, and extend the continuous production cycle; at the same time, it can also reduce the probability of condensation nuclei falling back to the glass melt surface or new fibers, significantly reduce the fiber breakage rate, and improve the product yield. The above technical solution eliminates the need to discharge gaseous volatiles outside the furnace, thus avoiding the loss of effective components and environmental pollution, achieving zero-emission clean production; at the same time, it eliminates the need for additional waste gas treatment, reduces equipment maintenance frequency, improves raw material utilization, and lowers overall production costs.

[0033] In the above technical solution, the porous glass microspheres can be prepared using conventional processes in the art. In some specific embodiments of the present invention, chemical etching is preferably performed according to the following steps: The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0034] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0035] Example 1 This embodiment prepares porous glass microspheres and applies them to environmental purification during the drawing of alkali-free glass fibers. The specific steps are as follows: First, 100 grams of alkali-free solid glass microspheres with a particle size of 1.0-2.0 mm are weighed, ultrasonically cleaned with anhydrous ethanol and deionized water, and then dried in an oven at 110℃ for 2 hours to complete the pretreatment. Then, in a 1000 mL three-necked flask equipped with a constant temperature heating magnetic stirrer, 500 mL of 1.5 mol / L hydrochloric acid solution is added as an etching solution, the temperature is controlled at 60℃, and the pretreated glass microspheres are added at a solid-liquid mass-volume ratio of 1 g: 5 mL. The reaction is carried out at a constant temperature for 90 minutes with a stirring speed of 300 rpm. After the reaction, vacuum filtration is performed immediately, and the filtrate is repeatedly washed with deionized water until the pH of the filtrate is neutral. Finally, the obtained microspheres are dried at 110℃ for 2 hours to obtain functionalized microspheres with uniform nanoscale pores on the surface. The BET specific surface area reaches 28.5 m² / g, and the microsphere structure is intact with a yield of 96%.

[0036] The pre-defined standard for the adsorption of gaseous volatiles by porous microspheres is subsequently determined by adsorption time. 300g of glass microspheres are weighed and evenly spread on a high-temperature resistant porous mesh basket above the molten glass surface in the furnace, ensuring they are precisely positioned along the main diffusion path of the gaseous volatiles. After the drawing furnace has been running for 24 hours and adsorption saturation has been achieved, characterization is performed using scanning electron microscopy (SEM) energy dispersive spectroscopy (EDS). The results show that the percentage of boron in the porous microspheres that adsorbed gaseous volatiles was approximately six times higher than in the unadsorbed porous glass microspheres, indicating that the technical solution of this embodiment can effectively recover key volatile components.

[0037] Example 2 In this embodiment, porous glass microspheres were prepared using an alkaline etching method and applied to the environmental purification of alkali-free glass fiber drawing, following the same method as in Example 1. The preparation steps of the porous glass microspheres were as follows: 100 grams of alkali-free solid glass microspheres with a particle size of 1.0-2.0 mm were weighed, washed and dried, and placed in a three-necked flask containing 500 mL of 0.8 mol / L sodium hydroxide solution. The mixture was stirred at 300 rpm for 40 minutes at a constant temperature of 80°C. After the reaction, the mixture was quickly filtered and separated, washed with deionized water until neutral, and finally dried at 110°C for 2 hours to obtain the finished product. The microspheres prepared under these conditions formed a unique micron-nano composite pore structure on their surface, with a BET specific surface area of ​​13.2 m² / g, exhibiting excellent capture ability for condensed droplets.

[0038] Example 3 In this embodiment, porous glass microspheres were prepared using a highly efficient etching process and then used for environmental purification during the drawing of alkali-free glass fibers, following the same method as in Example 1. The preparation steps for the porous glass microspheres were as follows: 100 grams of pretreated alkali-free glass microspheres were added to 500 mL of a 2.5 mol / L hydrochloric acid solution and stirred at 300 rpm for only 30 minutes at 80°C. After the reaction was completed, the mixture was immediately filtered, and after thorough washing and drying, porous microspheres were obtained.

[0039] In this embodiment, the enhanced corrosion conditions enabled the microspheres to achieve a specific surface area of ​​35.8 m² / g, exhibiting optimal adsorption performance. However, the mechanical strength of the microspheres decreased, making it suitable for applications with extremely high adsorption capacity requirements.

[0040] Example 4 This embodiment uses a mild corrosion process to prepare porous glass microspheres, and applies them to the environmental purification of alkali-free glass fiber drawing according to the same method as in Example 1. The preparation steps of the porous glass microspheres are as follows: 100 grams of pretreated alkali-free glass microspheres are placed in 500 mL of 0.8 mol / L hydrochloric acid solution and slowly stirred at 300 rpm for 120 minutes at a relatively low temperature of 50°C. After washing and drying with deionized water, the obtained microspheres maintain the best structural integrity, with a yield of up to 98% and a BET specific surface area of ​​8.7 m² / g. These high-strength porous microspheres are particularly suitable for industrial environments that require long-term use.

[0041] Example 5: In this embodiment, porous glass microspheres were prepared using nitric acid as an etchant and applied to the environmental purification process for drawing alkali-free glass fibers, following the same method as in Example 1. The preparation steps for the porous glass microspheres were as follows: 100 g of pretreated alkali-free glass microspheres were reacted with 500 mL of 2.0 mol / L nitric acid solution at 60 °C for 90 minutes while maintaining a stirring rate of 300 rpm. After a standard post-treatment process, the surface of the obtained microspheres formed a pore structure different from that formed by hydrochloric acid corrosion, with a BET specific surface area of ​​25.1 m² / g. This demonstrates that the method of this invention has good universality for different acid systems, providing more options for industrial production.

[0042] Comparative Example 1 This comparative example used a low-concentration acid solution for chemical corrosion, specifically reducing the hydrochloric acid concentration to 0.2 mol / L, while maintaining the same conditions as in Example 1. The result showed that the specific surface area of ​​the microspheres was only 0.5 m² / g, with no significant improvement compared to the raw material (0.1 m² / g). This indicates that at concentrations below 0.5 mol / L, the corrosion effect is weak, failing to effectively form a porous structure and making it difficult to apply to environmental purification during the drawing of alkali-free glass fibers.

[0043] Comparative Example 2 (concentration too high): This comparative example used a higher concentration of acid for chemical etching, specifically increasing the hydrochloric acid concentration to 5.0 mol / L, while maintaining the same conditions as in Example 1. The results showed severe microsphere breakage, with a yield of only 65% ​​and a specific surface area reduced to 5.2 m² / g. This indicates that concentrations exceeding 3.0 mol / L lead to uncontrolled corrosion and damage to the structural integrity of the microspheres.

[0044] Comparative Example 3 This comparative example used a longer chemical etching time for solid microspheres, specifically extending the reaction time to 180 minutes, while other conditions remained the same as in Example 1. The result was a large amount of microsphere pulverization, with a yield of only 58%, and the specific surface area decreased to 15.3 m² / g instead of increasing. This demonstrates that excessive etching occurs after a reaction time exceeding 120 minutes, leading to product failure.

[0045] Through a series of embodiments and comparative examples, this invention systematically verifies the feasibility of the porous glass microsphere preparation method, the optimized parameter range, and the consequences of exceeding the range.

[0046] Examples 1-5 successfully prepared functionalized microspheres with significant porous structures within the set parameter window. Their BET specific surface areas ranged from 8.7 to 35.8 m² / g, and the microsphere yields were all above 95%, exhibiting good structural integrity. In particular, Example 1 (1.5 mol / L HCl, 60°C, 90 minutes) achieved the optimal balance between specific surface area (28.5 m² / g) and structural integrity (96% yield), demonstrating excellent overall performance.

[0047] The comparative data clearly outline the technical boundaries of this invention from the opposite perspective. Comparative Example 1 (0.2 mol / L HCl) demonstrates that when the concentration of the corrosive solution is below 0.5 mol / L, the reaction driving force is insufficient, and the porous structure cannot be effectively constructed (specific surface area is only 0.5 m² / g). Comparative Example 2 (5.0 mol / L HCl) and Comparative Example 3 (180 minutes) show that when the concentration exceeds 3.0 mol / L or the time exceeds 120 minutes, the corrosion reaction becomes uncontrolled, leading to the destructive erosion of the microbead structure, manifested as a sharp decrease in yield (down to 65% and 58%, respectively) and abnormal specific surface area, resulting in the product losing its application value.

[0048] In summary, the experimental data fully demonstrate that the hydrochloric acid concentration of 0.5-3.0 mol / L and the reaction time of 20-120 minutes are the core optimized parameter ranges of this method.

[0049] Within this range, by adjusting the reaction temperature, the performance of the microbeads (such as high adsorption capacity and high mechanical strength) required for different application scenarios can be precisely customized. All embodiments achieved a balance between adsorption efficiency and material stability, while the comparative examples strongly demonstrate that deviating from the optimized parameters established in this invention will not yield the expected technical effects, thus highlighting the precision, reliability, and industrial application value of the technical solution of this invention.

[0050] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A porous glass microsphere for environmental purification using alkali-free glass fiber drawing, characterized in that, The porous glass microspheres have the same chemical composition as the molten glass used in the drawing of alkali-free glass fibers, and the surface of the porous glass microspheres has a nanoscale or micron-nano composite porous structure formed by chemical etching. The porous glass microspheres are used to adsorb and recover gaseous volatiles volatilized from the molten glass during the drawing process of alkali-free glass fibers.

2. The porous glass microspheres according to claim 1, characterized in that, The porous glass microspheres have a particle size of 1-2 mm and a BET specific surface area of ​​8-36 m² / g.

3. The application of porous glass microspheres in environmental purification through the drawing of alkali-free glass fibers, characterized in that... It includes the following steps: S1. The porous glass microspheres are placed above the molten glass in the drawing furnace in the diffusion path of the gaseous volatiles. The chemical composition of the porous glass microspheres is the same as that of the molten glass used to draw alkali-free glass fibers, and the surface of the porous glass microspheres has a nanoscale or micron-nano composite porous structure formed by chemical etching. S2 porous glass microspheres capture gaseous volatiles volatilized from the molten glass to a preset standard through their porous structure; The porous glass microspheres, after adsorbing gaseous volatiles in S3, are poured into the melting furnace to melt; the molten glass, after absorbing gaseous volatiles, is transported to the drawing furnace, where it is drawn into fibers by the drawing machine through the lower baffle plate.

4. The application according to claim 3, characterized in that, The preset standard is selected from at least one of adsorption time, microbead weight increment, and BET specific surface area decrease threshold.

5. The application according to claim 4, characterized in that, Based on the running time of the drawing furnace, the adsorption time for each batch of porous glass microspheres is 24-48 hours.

6. The application according to claim 3, characterized in that, The gaseous volatiles captured by the porous glass microspheres include boron- and / or fluorine-containing substances.

7. The application according to claim 3, characterized in that, The porous glass microspheres have a particle size of 1-2 mm and a BET specific surface area of ​​8-36 m² / g.

8. The application according to claim 3, characterized in that, The process of placing porous glass microspheres above the molten glass in the drawing furnace along the diffusion path of gaseous volatiles involves suspending a high-temperature resistant sieve-type material receiving trough in the area above the molten glass in the drawing furnace where the temperature is lower than the softening point of the glass microspheres; the porous glass microspheres are placed inside the material receiving trough.

9. The application according to any one of claims 3 to 7, characterized in that, The chemical corrosion includes the following steps: S1 involves ultrasonically cleaning and drying alkali-free solid glass microspheres with a particle size of 1.0~2.0 mm, then placing them in an etching solution under stirring conditions and etching them under preset conditions. S2 filtration, washing until neutral, drying, to obtain porous glass microspheres.

10. The application according to claim 9, characterized in that, The corrosive solution is a hydrochloric acid, nitric acid, or sodium hydroxide solution with a concentration of 0.8~2.5mol / L; the stirring speed is 250~350rpm; the preset conditions are as follows: solid-liquid ratio of 1g:4.5~5.5ml, reaction temperature of 50~80℃, and reaction time of 30~120min.