Method for preparing low-expansion quartz glass from reclaimed material
By crushing, ball milling and ultrasonic mixing of waste low-expanded quartz ingots, high-quality low-expanded quartz glass is prepared, which solves the problem that waste ingots cannot be reused and achieves efficient utilization of resources and environmental protection.
Patent Information
- Application Number
- CN202510162597.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-14
- Publication Date
- 2025-05-13
AI Technical Summary
In the existing low-expansion quartz glass production process, waste low-expansion quartz ingots cannot be effectively reused, resulting in waste of resources and environmental pollution.
Methods for preparing waste low-expanded quartz glass by crushing, ball milling, ultrasonic mixing, homogenizing, defoaming and drying.
It effectively reduces waste of waste, improves the uniformity of low-expanded quartz glass, avoids resource waste and environmental pollution, and improves corporate efficiency.
Smart Images
Figure CN119977292A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for preparing low-expansion quartz glass by utilizing recycled materials, belonging to the technical field of low-expansion quartz glass production. Background Art
[0002] Due to its excellent thermal expansion characteristics, chemical stability and excellent optical transmittance, low expansion coefficient quartz glass is widely used in aerospace, precision optics, electronic instruments and other fields, and the demand is large. The traditional method of producing low expansion quartz glass is to prepare high-purity silicon-containing chemicals and titanium-containing chemicals by chemical vapor deposition; however, the low expansion quartz ingots produced by this method will produce quality problems such as poor product uniformity due to uneven distribution of titanium elements, thereby generating a large amount of unqualified waste. These wastes cannot be directly reused, so they often need to be discarded, resulting in waste of resources and environmental pollution.
[0003] At present, the production process of low-expansion quartz glass is relatively fixed, and there is a lack of effective methods for recycling waste low-expansion quartz ingots. Therefore, it is necessary to develop a method for preparing low-expansion quartz glass again using quartz ingot waste generated by the existing method to avoid waste of resources and environmental pollution, thereby improving the efficiency of enterprises. Summary of the invention
[0004] The purpose of the present invention is to provide a method for preparing low-expansion quartz glass using recycled materials, which can reuse the quartz ingot waste generated by the existing method to avoid waste of resources and environmental pollution, thereby improving the efficiency of the enterprise.
[0005] The technical solution of the present invention is A method for preparing low expansion quartz glass using recycled materials, comprising the following steps: 1) First, check and classify the waste low-expansion quartz ingots (recycled materials) according to size and shape, and ensure that they do not contain large impurities. Then, use a crusher and a ball mill to crush and mill the waste low-expansion quartz ingots into 4~6μm powder particles; 2) Wash and dry the prepared powder particles in a conventional manner, and then sieve them. The particle size difference between the powder particles should not exceed 1 μm. Thus, fine powder particles with uniform particle size of 4 to 5 μm are obtained. 3) Mix the powder particles obtained above with 0.5 mol / L ammonia water or ultrapure water at a mass ratio of 60-75%:25-40%. When mixing, first pour the ammonia water or ultrapure water into the material barrel and place it in the ultrasonic machine. 4) Start the ultrasonic machine, add powder and granular materials into the material barrel in batches at a frequency of once every two minutes while ultrasonically stirring, until all the powder and granular materials are added and completely mixed with ammonia water or pure water; then the mixed slurry is obtained; 5) Pour the obtained mixed slurry into a ball mill (without adding balls) and rotate it at a speed of 28 / min for 12 hours for homogenization; 6) Place the homogenized mixed slurry in a vacuum degassing machine and degas at a rotation speed of 500-1500 rpm, a vacuum degree of -0.08 Mpa- -0.1 Mpa, and a time of 15-30 min to remove bubbles generated by stirring in the mixed slurry, so as to achieve a more uniform mixed slurry; 7) Evenly inject the degassed mixed slurry into a gypsum mold, dry it at 100-120 °C for 12-24 h, and then demold it to obtain a low-expansion quartz blank; 8) Place the quartz blank in a high-temperature furnace for debinding and sintering treatment; wherein the debinding temperature is 500-700°C, and the debinding time is 2-4 h; the sintering temperature is 1500-1700°C, and the sintering time is 2-3 h; and a sintered dense low-expansion quartz glass is obtained.
[0006] In actual work, it is found that when ammonia water or ultrapure water is used as a solvent, different ratios with powder particles have a direct impact on the fluidity of the mixed slurry. The applicant has compared different ratios; the results are as follows: Comparison table of different ratios
[0007] It can be seen from the above table that when 0.5 mol / L ammonia solution is used as the solvent, the maximum solid content of the ammonia solution can reach 70%.
[0008] When ultrapure water is used as a solvent, the maximum solid content of the solution can only be 60%. This is because silicon dioxide is an acidic oxide and ammonia is an alkaline solution. They can react as follows: SiO2+2NH3+H2O→(NH4)2SiO3 The ammonium silicate produced is soluble, which increases the solubility of silicon dioxide and the solid content of the solution.
[0009] It can be concluded that when 0.5 mol / L ammonia solution is used as solvent, its reaction with powder particles is The optimum ratio is 30%:70%. When ultrapure water is used as the solvent, the optimum ratio to powder particles is 40%:60%.
[0010] The beneficial effects of the present invention are: The present invention obtains a green blank by crushing, ball milling, ultrasonic mixing, homogenizing, degassing and drying the waste low-expansion quartz ingots; and then obtains the low-expansion quartz glass by debinding and high-temperature sintering. The present invention can not only effectively reduce the waste of waste materials by recycling the waste low-expansion quartz ingots, but also realize the secondary uniform dispersion of powder by ultrasonic mixing and homogenizing in slip casting, thereby significantly improving the uniformity of the low-expansion quartz glass, which has positive significance for avoiding waste of resources and environmental pollution, and improving enterprise benefits. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 The thermal expansion data comparison curve of the low expansion quartz glass prepared in Example 1 of the present invention and the waste glass is shown in FIG. Figure 1 It can be seen that the low expansion quartz glass prepared in Example 1 crosses the zero point at about 25° C., indicating that it has the performance of ultra-low expansion.
[0012] Figure 2 This is a CET uniformity test diagram of the low expansion quartz glass prepared in Example 1 of the present invention. Figure 2 It can be seen that the CET range of the prepared low expansion quartz glass is between -12 and 8 PPb / ℃, and the PV value (the difference between the maximum and the minimum) is 19.3088 PPb / ℃, indicating that the CET uniformity of the low expansion quartz glass is good.
[0013] Figure 3 This is a comparison curve of thermal expansion data of the low expansion quartz glass prepared in Example 2 of the present invention and waste glass. The prepared low expansion quartz glass crosses the zero point at about 37° C., indicating that it has ultra-low expansion performance.
[0014] Figure 4 This is a CET uniformity test diagram of the low expansion quartz glass prepared in Example 2 of the present invention. Figure 4 It can be seen that the CET range of the prepared low expansion quartz glass is between -15 and 15 PPb / ℃, the PV value (the difference between the maximum and the minimum) is 31.9796 PPb / ℃, and it can be seen from the figure that the CET value in most areas is around 0PPb / ℃, indicating that it has good CET uniformity and ultra-low expansion performance. DETAILED DESCRIPTION Example 1
[0015] First, the waste low-expansion quartz ingots are inspected and classified according to size and shape, and it is ensured that there are no large impurities in them. Then, the classified and selected waste low-expansion quartz ingots are crushed and ball-milled by a crusher and a ball mill to prepare 4~6μm powder particles. The prepared powder particles are washed and dried in a conventional manner, and then sieved. It is required that the particle size difference between the powder particles should not exceed 1μm; thus, a powder particle fine material with a uniform particle size of 4~5μm is obtained. The purpose of the particle size difference between the powder particles not exceeding 1μm is based on the fact that uniform powder particles have consistent surface characteristics and are relatively uniformly subjected to relative forces in the solvent. This consistency of force and movement is not easy to produce mutual attraction and aggregation between large and small particles, which helps to maintain the dispersion state of the powder; avoiding agglomeration is conducive to the preparation of more uniform low-expansion quartz glass with fewer bubbles. Then, the powdery particles obtained above are mixed with 0.5 mol / L ammonia water in a ratio of 70:30 by mass. When mixing, first pour the ammonia water into a barrel and place it in an ultrasonic machine. Start the ultrasonic machine, and while ultrasonically stirring, add the powdery particles into the barrel in batches at a frequency of once every two minutes until the powdery particles are added and completely mixed with the ammonia water. A mixed slurry of the powdery particles and ammonia water is obtained.
[0016] The obtained mixed slurry is injected into the ball mill (without adding balls) and homogenized at a rotation speed of 28 / min. During the homogenization process, when the ball mill rotates, the liquid and solid particles in the mixed slurry are affected by centrifugal force, causing the slurry to form convection in the tank. This convection helps the liquid and solid particles to circulate in the tank and improve the mixing effect. Without adding balls in the ball mill, the size of the solid particles remains uniform.
[0017] The homogenized mixed slurry is placed in a vacuum degassing machine and degassed at a rotation speed of 1500 rpm, a vacuum degree of -0.08Mpa, and a time of 30 min to remove bubbles generated by stirring in the mixed slurry, so as to achieve a more uniform mixed slurry. The degassed mixed slurry is evenly injected into the gypsum mold to shape the slurry. The principle is that when the liquid contacts the powder particles, the water molecules will enter the surface of the quartz powder, interact with the surface, form hydration products and hydrogen bonds, and fill the gaps. When the slurry is poured into the gypsum mold, the capillary force of the mold is used to remove the water content of the slurry, and the powder particles are rearranged, and the Si-O covalent bonds are cross-linked to form a network structure, so that the blank is tightly combined; the use of ammonia water will provide more abundant hydrogen bonds in the mixing process, so that the blank is more tightly combined, and the low expansion glass bubbles in the final sintering are less. The low-expansion quartz blank was dried at 120°C for 24 hours and then demolded to obtain the low-expansion quartz blank. The quartz blank was placed in a high-temperature furnace for debinding and sintering. The debinding temperature was 500°C and the debinding time was 3 hours. The sintering temperature was 1700°C and the sintering time was 2 hours. The sintered dense low-expansion quartz glass was obtained. Example 2
[0018] First, the waste low-expansion quartz ingots are inspected and classified according to size and shape, and it is ensured that there are no large impurities in them. Then, the classified and selected waste low-expansion quartz ingots are crushed and ball-milled by a crusher and a ball mill to prepare 4~6μm powder particles. The prepared powder particles are washed and dried in a conventional manner, and then sieved. It is required that the particle size difference between the powder particles should not exceed 1μm; thus, a powder particle fine material with a uniform particle size of 4~5μm is obtained. The purpose of the particle size difference between the powder particles not exceeding 1μm is based on the fact that uniform powder particles have consistent surface characteristics and are relatively uniformly subjected to relative forces in the solvent. This consistency of force and movement is not easy to produce mutual attraction and aggregation between large and small particles, which helps to maintain the dispersion state of the powder; avoiding agglomeration is conducive to the preparation of more uniform low-expansion quartz glass with fewer bubbles. Then, the powdery particles obtained above are mixed with ultrapure water in a ratio of 60:40 by mass. During mixing, firstly, the ultrapure water is poured into a barrel and placed in an ultrasonic machine. The ultrasonic machine is started, and while ultrasonic stirring is performed, the powdery particles are added into the barrel in batches at a frequency of once every two minutes until all the powdery particles are added and completely mixed with the ultrapure water. A mixed slurry of the powdery particles and ultrapure water is obtained.
[0019] The obtained mixed slurry is injected into the ball mill (without adding balls) and homogenized at a rotation speed of 28 / min. During the homogenization process, when the ball mill rotates, the liquid and solid particles in the mixed slurry are subjected to the centrifugal force, causing the slurry to form convection in the tank. This convection helps the liquid and solid particles to circulate in the tank and improve the mixing effect; without adding balls in the ball mill, the size of the solid particles remains uniform.
[0020] The homogenized mixed slurry is placed in a vacuum degassing machine and degassed at a rotation speed of 1500 rpm, a vacuum degree of -0.1Mpa, and a time of 30 min to remove bubbles generated by stirring in the mixed slurry, so as to achieve a more uniform mixed slurry. The degassed mixed slurry is evenly injected into the gypsum mold to shape the slurry. The principle is that when the liquid contacts the powder particles, the water molecules will enter the surface of the quartz powder, interact with the surface, form hydration products and hydrogen bonds, and fill the gaps. When the slurry is poured into the gypsum mold, the capillary force of the mold is used to remove the water content of the slurry, and the powder particles are rearranged, and the Si-O covalent bonds are cross-linked to form a network structure, so that the green blank is tightly combined; the low expansion glass bubbles in the final sintering are less. The low-expansion quartz blank was dried at 100 °C for 24 h and then demolded to obtain the low-expansion quartz blank. The quartz blank was placed in a high-temperature furnace for debinding and sintering. The debinding temperature was 700 °C and the debinding time was 4 h. The sintering temperature was 1500 °C and the sintering time was 3 h. The sintered dense low-expansion quartz glass was obtained.
Claims
1. A method for preparing low expansion quartz glass using recycled materials, comprising the following steps: 1) First, check and classify the waste low-expansion quartz ingots according to size and shape, and ensure that they do not contain large impurities. Then, use a crusher and a ball mill to crush and mill the waste low-expansion quartz ingots into 4~6μm powder particles; 2) Wash and dry the prepared powder particles in a conventional manner, and then sieve them. It is required that the particle size difference between the powder particles should not exceed 1 μm. Thus, fine powder particles with uniform particle size of 4-5 μm are obtained. 3) Mix the powder particles obtained above with 0.5 mol / L ammonia water or ultrapure water at a mass ratio of 60-75%:25-40%. When mixing, first pour the ammonia water or ultrapure water into the barrel and place it in the ultrasonic machine; 4) Start the ultrasonic machine, while ultrasonically stirring, add powder and granular materials into the barrel in batches at a frequency of once every two minutes until all the powder and granular materials are added and completely mixed with ammonia water or pure water; Get, mixed slurry; 5) Pour the obtained mixed slurry into a ball mill and rotate it at a speed of 28 / min (time) for homogenization; 6) Place the homogenized mixed slurry in a vacuum degassing machine and degas under the conditions of a stirring speed of 500-1500 rpm, a vacuum degree of -0.08 Mpa- -0.1 Mpa, and a time of 15-30 min to remove bubbles generated by stirring in the mixed slurry, so as to achieve a more uniform mixed slurry; 7) Evenly inject the degassed mixed slurry into a plaster mold, dry it at 100-120°C for 12-24 hours, and then demold it to obtain a low-expansion quartz blank; 8) Place the quartz blank in a high-temperature furnace for debinding and sintering treatment; wherein the debinding temperature is 500-700°C, and the debinding time is 2-4 h; the sintering temperature is 1500-1700°C, and the sintering time is 2-3 h; and a sintered dense low-expansion quartz glass is obtained.
2. The method for preparing low expansion quartz glass using recycled materials according to claim 1, characterized in that: The mass ratio of powder particle fine material to 0.5 mol / L ammonia water is 70%:30%.
3. The method for preparing low expansion quartz glass using recycled materials according to claim 1, characterized in that: The mass ratio of powder particle fine material to ultrapure water is 60%:40%.