Quartz glass preparation method using quartz powder as raw material and quartz product

Abstract

The invention provides a quartz glass preparation method using quartz powder as a raw material and a quartz product. The quartz glass preparation method using quartz powder as a raw material comprises the following steps: providing quartz powder as an initial raw material; performing pretreatment on the initial raw material to obtain a static pressure raw material containing quartz powder, wherein the pretreatment at least comprises a process of screening the initial raw material and a process of performing dehydroxylation; performing static pressure treatment on the static pressure raw material in a static pressure device to obtain a quartz powder block, wherein the part, which is in contact with quartz powder, in the static pressure device is made of a high-purity quartz material; and placing the quartz powder block in a container of which the contact surface is made of high-purity quartz, and vitrifying the quartz powder block to obtain the quartz glass.

Description

Technical Field

[0001] This application relates to the field of materials and chemical engineering, and in particular to a method for preparing quartz glass using quartz powder as a raw material and quartz products. Background Art

[0002] The preparation technologies of quartz glass mainly include two categories: physical method and chemical method at present. Among them, the chemical method is to synthesize silicon dioxide particles by hydrolysis of silicon-containing raw materials, and then further obtain quartz glass. According to different synthesis processes, the chemical method can be divided into two-step method and one-step method. The one-step method uses silicon sources such as silicon tetrachloride and organosilane to directly prepare quartz glass ingots after high-temperature hydrolysis. The main processes include CVD and PCVD. The two-step method deposits silicon dioxide powder on the substrate in the form of a loose body through high-temperature hydrolysis of the silicon source to form a loose body, and then prepares quartz glass by high-temperature heating of the loose body. The main processes include VAD and OVD. Among them, the physical method is to use high-purity quartz powder to form quartz glass after high-temperature melting and solidification by means of gas melting, electric melting, etc. The physical melting method can use high-purity quartz powder as a raw material. The quartz powder is poured into a high-temperature-resistant crucible container, and the quartz powder is melted by high-temperature heating, and then the molten quartz is cooled and solidified into a large piece of quartz glass. Since the melting temperature of quartz is extremely high (usually greater than 1700 °C), high-melting-point oxide ceramics (such as alumina, zirconia, etc.) and high-melting-point single substances (molybdenum, tungsten, carbon, etc.) are usually used for the crucibles for melting. In the quartz obtained by the direct high-temperature melting process of quartz powder, since quartz still has a very high viscosity during melting, it is difficult to remove the gas in the powder voids, and it is easy to remain in the quartz glass in the form of bubbles. In addition, high-temperature melting inevitably needs to come into contact with the crucible container for melting, and the elements contained in the crucible itself will gradually penetrate to form pollution; due to the purity limitation of the crucible material for melting, other impurities existing in the melting crucible will also penetrate into the quartz glass, and ultimately will affect the purity of the quartz glass.

[0003] In the general technology, high-purity quartz powder is used as a raw material. The powder is poured into a dispersion formed by water, an organic substance, or a mixture of both. The quartz powder and the dispersion are mixed evenly to form a slurry by means of ball milling, stirring, etc.; the uniform slurry is poured into a specific mold and formed by freezing or air-drying. After forming, the block is separated from the mold. At this time, a large amount of dispersion still remains in the block. The residual dispersion substances in the block are volatilized by drying to form a dry quartz powder block, and finally a transparent quartz glass is formed through high-temperature sintering. The method of forming through slurry can optimize the problems of bubbles and cracking inside the glass to a certain extent, but it is affected by the purity of the dispersion itself and the materials of the ball milling equipment (usually alumina, zirconia, etc.), which exacerbates the contamination of the quartz glass by impurities. In addition, the quartz glass prepared by the technology of physical melting of quartz powder is difficult to have indicators such as low residual stress and high optical uniformity, and it is difficult to be applied in cutting-edge fields such as semiconductors and high-energy lasers. How to solve the above problems is what those skilled in the art need to consider. Summary of the Invention

[0004] To solve the above problems, the embodiments of the present application provide a method for preparing high-purity quartz using quartz powder as a raw material and a quartz product prepared by applying this method, and a quartz product with high optical uniformity, low stress, low hydroxyl, and high purity can be obtained.

[0005] The embodiments of the present application provide a method for preparing a quartz glass using quartz powder as a raw material, which includes the following steps: Provide quartz powder as an initial raw material; Perform pretreatment on the initial raw material to obtain a hydrostatic raw material containing quartz powder. The pretreatment includes at least a process of screening the initial raw material and a process of dehydroxylating the initial raw material; Place the hydrostatic raw material in a hydrostatic device for hydrostatic treatment to obtain a quartz powder block. The parts in the hydrostatic device that come into contact with the quartz powder are all made of high-purity quartz material; Place the quartz powder block in a container with a contact surface made of high-purity quartz, and vitrify the quartz powder block to obtain a quartz glass.

[0006] In one embodiment, the step of screening the initial raw material includes: Vibrate and screen the quartz powder using a sieve to obtain silicon dioxide particles with a particle size of 50 nanometers to 300 micrometers.

[0007] In one embodiment, the particle size of the silicon dioxide particles is 100 nanometers to 200 micrometers.

[0008] In one embodiment, the step of dehydroxylating the initial raw material includes: Place the quartz powder in a dehydroxylation furnace, evacuate the interior of the dehydroxylation furnace to a vacuum state, and control the vacuum degree inside the dehydroxylation furnace to be less than 10 Pa; Heat the quartz powder in the dehydroxylation furnace to remove the hydroxyl groups inside the quartz powder. Control the dehydroxylation temperature of the dehydroxylation furnace to be 500 °C to 1300 °C, and control the dehydroxylation holding time of the dehydroxylation furnace to be 10 hours to 100 hours.

[0009] In one embodiment, control the vacuum degree inside the dehydroxylation furnace to be less than 1 Pa; Control the dehydroxylation temperature of the dehydroxylation furnace to be 700 °C to 1100 °C, and control the dehydroxylation holding time of the dehydroxylation furnace to be 40 hours to 80 hours.

[0010] In one embodiment, control the static pressure of the static pressure device for static pressure treatment of the static pressure raw material to be 2 MPa to 15 Mpa, and control the pressure holding time of the static pressure device for static pressure treatment of the static pressure raw material to be 5 minutes to 120 minutes; control the density of the quartz powder block obtained by static pressure treatment in the static pressure device to be 0.2 g / cm 3 to 1.8 g / cm 3 .

[0011] In one embodiment, control the static pressure of the static pressure device for static pressure treatment of the static pressure raw material to be 5 MPa to 10 Mpa, and control the pressure holding time of the static pressure device for static pressure treatment of the static pressure raw material to be 30 minutes to 60 minutes; control the density of the quartz powder block obtained by static pressure treatment in the static pressure device to be 0.5 g / cm 3 to 0.6 g / cm 3 .

[0012] In one embodiment, the static pressure device includes a base and a plurality of static pressure components arranged around the base; The base and the plurality of static pressure components cooperate to form a static pressure cavity for accommodating the quartz powder. The positions of the plurality of static pressure components relative to the base are adjustable for squeezing the quartz powder in the static pressure cavity; The surfaces of the base and the plurality of static pressure components for contacting the quartz powder are all made of high-purity quartz material.

[0013] In one embodiment, control the vitrification temperature range of the quartz powder block to be 1350 °C to 1500 °C, and control the vitrification time of the quartz powder block to be 10 hours to 90 hours.

[0014] In one embodiment, the vitrification temperature range for controlling the vitrification of the quartz powder mass is 1400°C to 1480°C, and the vitrification time for controlling the vitrification of the quartz powder mass is 40 hours to 60 hours.

[0015] An embodiment of the present application also provides a quartz product, which is obtained by the method for preparing quartz glass using quartz powder as a raw material described in any one of the foregoing embodiments.

[0016] Furthermore, the method for preparing quartz glass using quartz powder as a raw material provided by the embodiment of the present application can obtain quartz products with high optical uniformity, low stress, low hydroxyl content, and high purity. On the one hand, by dispersing, screening, and dehydroxylating the quartz powder, controlling the hydroxyl content of the powder, and thus controlling the hydroxyl content of the quartz glass, it is possible to achieve the preparation of quartz glass with a hydroxyl content below 1 ppm. On the other hand, a static pressure device in which all parts in contact with the quartz powder are made of quartz is used to apply static pressure to the quartz powder, avoiding the introduction of impurities due to contact, and pressing out a quartz powder mass with specific specifications and specific density. On the further hand, the present application adopts a process similar to the two-step method, enabling the quartz powder to slowly shrink in a non-molten environment, and preparing high-purity synthetic quartz glass. The product has the characteristics of high purity, low hydroxyl content, no bubbles, no streaks, high optical uniformity, and low stress. Description of the Drawings

[0017] Figure 1 It is a schematic flow chart of the method for preparing quartz glass using quartz powder as a raw material provided by the embodiment of the present application.

[0018] Figure 2 It is a schematic structural diagram of the static pressure device applied in the method for preparing quartz glass using quartz powder as a raw material provided by the embodiment of the present application.

[0019] Figure 3 It is a schematic structural diagram of the static pressure device applied in the method for preparing quartz glass using quartz powder as a raw material provided by the embodiment of the present application.

[0020] Description of the Main Component Symbols Static pressure device 10 Static pressure cavity 100 Base 11 Support part 111 Quartz bottom pad 112 Static pressure component 12 Pressing rod 121 Connecting push block 122 Quartz extrusion gasket 123 Quartz powder mass 20 The following specific embodiments will further illustrate the present application in conjunction with the above-mentioned drawings. Specific Embodiments

[0021] The following description will describe the content of the present application more comprehensively with reference to the accompanying drawings. The exemplary embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. These exemplary embodiments are provided to make the present application thorough and complete, and to fully convey the scope of the present application to those skilled in the art. Similar reference numerals denote the same or similar components.

[0022] The terms used herein are for the purpose of describing particular exemplary embodiments only and are not intended to limit the present application. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms as well. Further, when used herein, "comprising" and / or "including" and / or "having", integers, steps, operations, components and / or components, but do not exclude the presence or addition of one or more other features, regions, integers, steps, operations, components and / or groups thereof.

[0023] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Further, unless explicitly defined herein, terms such as those defined in a general dictionary should be construed to have a meaning consistent with their meaning in the relevant art and the content of this application, and will not be construed as having an idealized or overly formal meaning.

[0024] Generally, high-purity quartz powder is used as a raw material in the general technology. The powder is poured into a dispersion formed by water, an organic substance or a mixture of both, and the quartz powder and the dispersion are mixed evenly to form a slurry by means of ball milling, stirring, etc.; the uniform slurry is poured into a specific mold and formed by freezing or drying, and after forming, the block is separated from the mold. At this time, a large amount of dispersion still remains in the block, and the residual dispersion substance in the block is volatilized by drying to form a dry quartz powder block, and finally a transparent quartz glass is formed through high-temperature sintering. The method of forming through slurry can optimize the problems of bubbles and cracking inside the glass to a certain extent, but it is affected by the purity of the dispersion itself and the material of the ball milling equipment (usually alumina, zirconia, etc.), which exacerbates the contamination of the quartz glass by impurities.

[0025] For example, foreign patent application EP2050724A1 proposes a method for preparing a quartz glass block from high-temperature molten quartz particles, in which a vibrating rod with a surface coated with quartz glass is inserted into the powder, and after being compacted to a density of 1.4 g / cm 3 to 1.6 g / cm 3Subsequently, it is melted at high temperature in a ceramic furnace, and fused silica glass is prepared after cooling. This method avoids the introduction of impurities by adding quartz plates or molybdenum plates inside an alumina or zirconia furnace. However, since the temperature during high-temperature melting reaches 1790 °C, the quartz plates used for blocking will also be melted and cannot prevent the infiltration of impurities; although the melting point of molybdenum plates is relatively high, molybdenum itself will also diffuse into the fused silica glass at high temperature, affecting the purity of the fused silica glass obtained. At the same time, this method uses a vibrating rod to compact the material to remove the gas in the particle gaps. The efficiency is low, and the friction between the quartz powder and the crucible wall will be aggravated during the vibration process, increasing the risk of impurity introduction. This patent uses a method of passing high-pressure helium gas to remove the water vapor and gas molecules adsorbed on the quartz powder, but it cannot effectively remove the hydroxyl groups in the quartz powder. Foreign patent application EP3390306A2 proposes a method for preparing fused silica glass by high-temperature melting of quartz particles in a suspended sintering crucible. Among them, the quartz powder raw material is prepared by an atomization method, and the quartz particles are continuously melted at high temperature in a furnace made of molybdenum / tungsten material, and fused silica glass products are continuously produced at the lower opening of the furnace. The common metal impurities in the fused silica glass prepared by this method are relatively high, close to 1 ppm. At the same time, due to the use of a furnace made of molybdenum and tungsten materials, the metal penetration in the furnace material is obvious, and the content also reaches 1 ppm. In addition, this method is a continuous preparation method and cannot remove the moisture and hydroxyl groups in the powder. The hydroxyl group content of the prepared product is 200-400 ppm. Foreign patent application DE102011120932A1 provides a process route for preparing transparent fused silica glass from silica slurry. The slurry is a homogeneous mixture of silica and water or water and organic matter ground evenly by alumina grinding balls. After pouring the slurry into a specific mold, it is frozen and formed, then dried at a low temperature to remove moisture, and sintered at a high temperature to obtain transparent fused silica glass. The method involved in this patent can solve the problem of internal bubbles in the material, but the process flow is complex. Moreover, during the mixing process of the complex solution system involved in this method of preparation, substances such as the grinding balls and solutions in contact will introduce impurities. At the same time, since the preparation process is a liquid phase system, it is difficult to control the hydroxyl group content of the prepared fused silica glass material. At the same time, the fused silica glass prepared by using the physical melting technology of quartz powder cannot meet the high-end optical performance indicators such as low residual stress and high optical uniformity.

[0026] Correspondingly, the present application provides a method for preparing high-purity quartz with low stress, high optical uniformity, and low hydroxyl using quartz powder as a raw material, and a quartz product prepared by applying this method. The method for preparing quartz glass using quartz powder as a raw material includes the following steps: providing quartz powder as the initial raw material; performing pretreatment on the initial raw material to obtain a static pressure raw material containing quartz powder, and the pretreatment includes at least the process of screening the initial raw material and the process of dehydroxylating the initial raw material; placing the static pressure raw material in a static pressure device for static pressure treatment to obtain a quartz powder block, and the parts of the static pressure device that come into contact with the quartz powder are all made of high-purity quartz material; placing the quartz powder block in a container with a contact surface made of high-purity quartz, and vitrifying the quartz powder block to obtain quartz glass.

[0027] Furthermore, the method for preparing quartz glass using quartz powder as a raw material provided by the embodiments of the present application can obtain high-purity quartz products. On the one hand, by dispersing, screening, and dehydroxylating the quartz powder, controlling the hydroxyl content of the powder, and thus controlling the hydroxyl content of the quartz glass, it is possible to prepare quartz glass with a hydroxyl content below 1 ppm. On the other hand, using a static pressure device in which the parts in contact with the quartz powder are all made of high-purity quartz material to perform static pressure on the quartz powder, avoiding the introduction of impurities due to contact, and pressing out a quartz powder block with specific specifications and specific density. On the other hand, the present application adopts an imitation two-step process to prepare high-purity synthetic quartz glass in a non-molten environment, and the product has the characteristics of high purity, low hydroxyl, low stress, high optical uniformity, no bubbles, and no streaks.

[0028] The following refers to the accompanying drawings to further describe in detail the specific embodiments of the present application.

[0029] A method for preparing quartz glass using quartz powder as a raw material, which includes the following steps: providing quartz powder as the initial raw material; performing pretreatment on the initial raw material to obtain a static pressure raw material containing quartz powder, and the pretreatment includes at least the process of screening the initial raw material and the process of dehydroxylating the initial raw material; placing the static pressure raw material in a static pressure device for static pressure treatment to obtain a quartz powder block, and the parts of the static pressure device that come into contact with the quartz powder are all made of high-purity quartz material; placing the quartz powder block in a container with a contact surface made of high-purity quartz, and vitrifying the quartz powder block to obtain quartz glass.

[0030] It is understandable that during the whole process of converting quartz powder into quartz products (quartz glass), no contact with other materials is involved to ensure the high purity of the quartz products. At the same time, through the dehydroxylation process, non-metallic impurities (such as hydroxyl groups) in the quartz powder are controlled at an extremely low level below 1 ppm. Therefore, the method for preparing high-purity quartz using quartz powder as a raw material provided by the embodiments of the present application can obtain quartz products with high optical uniformity, low stress, low hydroxyl content, and high purity.

[0031] It is understandable that "high purity" means that the purity of the high-purity quartz is greater than or equal to 99.99% (4N). Further, the purity of the high-purity quartz can also be greater than or equal to 99.99999% (7N). Furthermore, the "high purity" refers to an ultra-high purity with metal impurity ions at the ppb level (parts per billion, one in a billion) and a purity greater than 99.999999% (8N).

[0032] As Figure 1 shown, the embodiments of the present application provide a method for preparing quartz glass using quartz powder as a raw material, which includes the following steps: Step S1: Provide quartz powder as the initial raw material.

[0033] It is understandable that the quartz powder can be natural quartz powder, high-purity synthetic quartz powder, and high-purity quartz waste powder generated during the deposition process.

[0034] Step S2: Perform pretreatment on the initial raw material to obtain a static pressure raw material containing quartz powder. The pretreatment at least includes the process of screening the initial raw material and the process of dehydroxylating the initial raw material.

[0035] It is understandable that the process of screening the initial raw material and the process of dehydroxylating the initial raw material can be two independent processes, corresponding to step S21 and step S22 respectively.

[0036] Step S21, the process of screening the initial raw material includes: Vibrate and screen the quartz powder using a sieve to obtain silicon dioxide microparticles with a particle size of 50 nanometers to 300 micrometers.

[0037] In one embodiment, the particle size of the silicon dioxide microparticles is 100 nanometers to 200 micrometers.

[0038] In one embodiment, the particle size of the silicon dioxide microparticles is 1 micrometer to 100 micrometers.

[0039] In this embodiment, the particle size of the silica microparticles can specifically be 50 nanometers, 60 nanometers, 70 nanometers, 80 nanometers, 90 nanometers, 100 nanometers, 150 nanometers, 200 nanometers, 250 nanometers, 300 nanometers, 350 nanometers, 400 nanometers, 450 nanometers, 500 nanometers, 550 nanometers, 600 nanometers, 650 nanometers, 700 nanometers, 750 nanometers, 800 nanometers, 850 nanometers, 900 nanometers, 950 nanometers, 1000 nanometers; 2 micrometers, 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, 15 micrometers, 16 micrometers, 17 micrometers, 18 micrometers, 19 micrometers, 20 micrometers, 21 micrometers, 22 micrometers, 23 micrometers, 24 micrometers, 25 micrometers, 26 micrometers, 27 micrometers, 28 micrometers, 29 micrometers, 30 micrometers, 31 micrometers, 32 micrometers, 33 micrometers, 34 micrometers, 35 micrometers, 36 micrometers, 37 micrometers, 38 micrometers, 39 micrometers, 40 micrometers, 41 micrometers, 42 micrometers, 43 micrometers, 44 micrometers, 45 micrometers, 46 micrometers, 47 micrometers, 48 micrometers, 49 micrometers, 50 micrometers, 51 micrometers, 52 micrometers, 53 micrometers, 54 micrometers, 55 micrometers, 56 micrometers, 57 micrometers, 58 micrometers, 59 micrometers, 60 micrometers, 61 micrometers, 62 micrometers, 63 micrometers, 64 micrometers, 65 micrometers, 66 micrometers, 67 micrometers, 68 micrometers, 69 micrometers, 70 micrometers, 71 micrometers, 72 micrometers, 73 micrometers, 74 micrometers, 75 micrometers, 76 micrometers, 77 micrometers, 78 micrometers, 79 micrometers, 80 micrometers, 81 micrometers, 82 micrometers, 83 micrometers, 84 micrometers, 85 micrometers, 86 micrometers, 87 micrometers, 88 micrometers, 89 micrometers, 90 micrometers, 91 micrometers, 92 micrometers, 93 micrometers, 94 micrometers, 95 micrometers, 96 micrometers, 97 micrometers, 98 micrometers, 99 micrometers; 100 micrometers, 110 micrometers, 120 micrometers, 130 micrometers, 140 micrometers, 150 micrometers, 160 micrometers, 170 micrometers, 180 micrometers, 190 micrometers, 200 micrometers, 210 micrometers, 220 micrometers, 230 micrometers, 240 micrometers, 250 micrometers, 260 micrometers, 270 micrometers, 280 micrometers, 290 micrometers, 300 micrometers.

[0040] It is understandable that the purity of the high-purity quartz powder selected in this application is greater than or equal to 4N, and preferably greater than or equal to 7N. The high-purity quartz powder is subjected to vibration screening to select quartz powder with a particle size meeting the requirements. The screen of the vibrating screen is made of high-purity nylon, and the trays, lids and the peripheries of the screens of the sieves are all made of high-purity plastics. Preferably, an ultrasonic vibrating screen can be used to improve the dispersibility of the powder. During the screening process, by adjusting the aperture of the screen, high-dispersibility high-purity silica microparticles with a particle size of 50 nm to 300 μm are obtained. Preferably, the particle size of the quartz powder is 100 nm to 200 microns, and more preferably, the particle size range of the quartz powder is 1 μm to 100 μm. The high-dispersibility high-purity silica fine powder obtained after screening is poured into a high-purity quartz container for standby.

[0041] Step S22: The step of dehydroxylating the initial raw material includes: Place the quartz powder in a dehydroxylation furnace, evacuate the inside of the dehydroxylation furnace to a vacuum state, and control the vacuum degree inside the dehydroxylation furnace to be less than 10 Pa; Heat the quartz powder in the dehydroxylation furnace to remove the hydroxyl groups inside the quartz powder; and / or, control the dehydroxylation temperature of the dehydroxylation furnace for dehydroxylation to be 500°C to 1300°C; and / or, control the dehydroxylation holding time of the dehydroxylation furnace for dehydroxylation to be 10 hours to 100 hours.

[0042] In one embodiment, control the vacuum degree inside the dehydroxylation furnace to be less than 1 Pa; and / or, control the dehydroxylation temperature of the dehydroxylation furnace for dehydroxylation to be 700°C to 1100°C; and / or, control the dehydroxylation holding time of the dehydroxylation furnace for dehydroxylation to be 40 hours to 80 hours.

[0043] In this embodiment, the vacuum degree inside the dehydroxylation furnace can be further controlled to be less than 0.1 Pa.

[0044] It can be understood that the quartz powder obtained by high-temperature hydrolysis of the silicon source contains a large amount of hydroxyl groups, which affect the performance of quartz glass. Therefore, the control of the hydroxyl content in quartz glass is particularly important. The quartz powder itself has a large specific surface area, and the diffusion rate of hydroxyl groups is also faster than that in quartz glass. Removing hydroxyl groups at this stage is an opportune time to control the hydroxyl content of the quartz glass block. Place the quartz container filled with silicon dioxide powder in a dehydroxylation furnace, and evacuate the inside of the furnace to a vacuum state for dehydroxylation to effectively remove hydroxyl groups. Among them, control the vacuum degree in the dehydroxylation furnace to be less than 10 Pa, preferably less than 1 Pa, and more preferably less than 0.1 Pa; use high-temperature heating to promote the removal of hydroxyl groups inside the quartz particles, and adjust the hydroxyl content in the quartz powder as needed. By adjusting parameters such as the heat preservation temperature and heat preservation time of the vacuum furnace, the hydroxyl content in the quartz powder can be controlled below 1 ppm. Among them, control the dehydroxylation temperature in the dehydroxylation furnace to be 500 °C to 1300 °C, preferably the temperature range is 700 °C to 1100 °C; and / or, control the dehydroxylation heat preservation time in the dehydroxylation furnace to be 10 hours to 100 hours, preferably the dehydroxylation heat preservation time is 40 hours to 80 hours.

[0045] In this embodiment, the calibrated value of the vacuum degree in the dehydroxylation furnace can further be 0.1 Pa, 0.2 Pa, 0.3 Pa, 0.4 Pa, 0.5 Pa, 0.6 Pa, 0.7 Pa, 0.8 Pa, 0.9 Pa, 1 Pa, 2 Pa, 3 Pa, 4 Pa, 5 Pa, 6 Pa, 7 Pa, 8 Pa, 9 Pa, 10 Pa.

[0046] In this embodiment, the value of the dehydroxylation temperature for controlling the dehydroxylation furnace to perform dehydroxylation can specifically be 500 °C, 510 °C, 520 °C, 530 °C, 540 °C, 550 °C, 560 °C, 570 °C, 580 °C, 590 °C, 600 °C, 610 °C, 620 °C, 630 °C, 640 °C, 650 °C, 660 °C, 670 °C, 680 °C, 690 °C, 700 °C, 710 °C, 720 °C, 730 °C, 740 °C, 750 °C, 760 °C, 770 °C, 780 °C, 790 °C, 800 °C, 810 °C, 820 °C, 830 °C, 840 °C, 850 °C, 860 °C, 870 °C, 880 °C, 890 °C, 900 °C, 910 °C, 920 °C, 930 °C, 940 °C, 950 °C, 960 °C, 970 °C, 980 °C, 990 °C, 1000 °C, 1010 °C, 1020 °C, 1030 °C, 1040 °C, 1050 °C, 1060 °C, 1070 °C, 1080 °C, 1090 °C, 1100 °C, 1110 °C, 1120 °C, 1130 °C, 1140 °C, 1150 °C, 1160 °C, 1170 °C, 1180 °C, 1190 °C, 1200 °C, 1210 °C, 1220 °C, 1230 °C, 1240 °C, 1250 °C, 1260 °C, 1270 °C, 1280 °C, 1290 °C, 1300 °C.

[0047] In this embodiment, the dehydroxylation holding time for controlling the dehydroxylation furnace to perform dehydroxylation can specifically be 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, 30 hours, 31 hours, 32 hours, 33 hours, 34 hours, 35 hours, 36 hours, 37 hours, 38 hours, 39 hours, 40 hours, 41 hours, 42 hours, 43 hours, 44 hours, 45 hours, 46 hours, 47 hours, 48 hours, 49 hours, 50 hours, 51 hours, 52 hours, 53 hours, 54 hours, 55 hours, 56 hours, 57 hours, 58 hours, 59 hours, 60 hours, 61 hours, 62 hours, 63 hours, 64 hours, 65 hours, 66 hours, 67 hours, 68 hours, 69 hours, 70 hours, 71 hours, 72 hours, 73 hours, 74 hours, 75 hours, 76 hours, 77 hours, 78 hours, 79 hours, 80 hours, 81 hours, 82 hours, 83 hours, 84 hours, 85 hours, 86 hours, 87 hours, 88 hours, 89 hours, 90 hours, 91 hours, 92 hours, 93 hours, 94 hours, 95 hours, 96 hours, 97 hours, 98 hours, 99 hours, 100 hours.

[0048] In other embodiments, dehydroxylation can also be achieved by introducing chlorine and sintering at high temperature in an air environment in the dehydroxylation furnace for a long time. Those skilled in the art can understand that this is certainly feasible and will not be elaborated here.

[0049] Step S3: Place the static pressure raw material in a static pressure device for static pressure treatment to obtain a quartz powder block. All parts of the static pressure device that come into contact with the quartz powder are made of high-purity quartz.

[0050] In one embodiment, the static pressure device includes a base and a plurality of static pressure components arranged around the base; the base and the plurality of static pressure components cooperate to form a static pressure cavity for accommodating the quartz powder. The positions of the plurality of static pressure components relative to the base are adjustable for squeezing the quartz powder in the static pressure cavity; the surfaces of the base and the plurality of static pressure components that come into contact with the quartz powder are made of high-purity quartz.

[0051] In one embodiment, the static pressure for controlling the static pressure device to perform static pressure treatment on the static pressure raw material is 2 MPa to 15 Mpa, and the pressure holding time for controlling the static pressure device to perform static pressure treatment on the static pressure raw material is 5 minutes to 120 minutes; the density of the quartz powder block obtained by the static pressure treatment in the static pressure device is 0.2 g / cm 3 to 1.8 g / cm 3 .

[0052] Furthermore, the static pressure for controlling the static pressure device to perform static pressure treatment on the static pressure raw material is 5 MPa to 10 Mpa, and the pressure holding time for controlling the static pressure device to perform static pressure treatment on the static pressure raw material is 30 minutes to 60 minutes; the density of the quartz powder block obtained by the static pressure treatment in the static pressure device is 0.5 g / cm 3 to 0.6 g / cm 3 .

[0053] Even further, the static pressure for controlling the static pressure device to perform static pressure treatment on the static pressure raw material is 6 MPa to 8 Mpa.

[0054] It can be understood that the static pressure device presses the quartz powder into a quartz powder body with a specific density. Among them, the static pressure is 2 MPa to 15 MPa, the preferred static pressure is 5 MPa to 10 MPa, and the more preferred static pressure is 6 MPa to 8 MPa; the pressure holding time of the static pressure is 5 minutes to 120 minutes, and the preferred pressure holding time is 30 - 60 minutes. The density of the obtained quartz powder block is 0.2 g / cm 3 to 1.8 g / cm 3 , and the preferred density range of the quartz powder block is 0.5 g / cm 3 to 0.6 g / cm3 。

[0055] In this embodiment, the static pressure for controlling the static pressure device to perform static pressure treatment on the static pressure raw material can specifically be 2.0 MPa, 2.1 MPa, 2.2 MPa, 2.3 MPa, 2.4 MPa, 2.5 MPa, 2.6 MPa, 2.7 MPa, 2.8 MPa, 2.9 MPa, 3.0 MPa, 3.1 MPa, 3.2 MPa, 3.3 MPa, 3.4 MPa, 3.5 MPa, 3.6 MPa, 3.7 MPa, 3.8 MPa, 3.9 MPa, 4.0 MPa, 4.1 MPa, 4.2 MPa, 4.3 MPa, 4.4 MPa, 4.5 MPa, 4.6 MPa, 4.7 MPa, 4.8 MPa, 4.9 MPa, 5.0 MPa, 5.1 MPa, 5.2 MPa, 5.3 MPa, 5.4 MPa, 5.5 MPa, 5.6 MPa, 5.7 MPa, 5.8 MPa, 5.9 MPa, 6.0 MPa, 6.1 MPa, 6.2 MPa, 6.3 MPa, 6.4 MPa, 6.5 MPa, 6.6 MPa, 6.7 MPa, 6.8 MPa, 6.9 MPa, 7.0 MPa, 7.1 MPa, 7.2 MPa, 7.3 MPa, 7.4 MPa, 7.5 MPa, 7.6 MPa, 7.7 MPa, 7.8 MPa, 7.9 MPa, 8.0 MPa, 8.1 MPa, 8.2 MPa, 8.3 MPa, 8.4 MPa, 8.5 MPa, 8.6 MPa, 8.7 MPa, 8.8 MPa, 8.9 MPa, 9.0 MPa, 9.1 MPa, 9.2 MPa, 9.3 MPa, 9.4 MPa, 9.5 MPa, 9.6 MPa, 9.7 MPa, 9.8 MPa, 9.9 MPa, 10.0 MPa, 10.1 MPa, 10.2 MPa, 10.3 MPa, 10.4 MPa, 10.5 MPa, 10.6 MPa, 10.7 MPa, 10.8 MPa, 10.9 MPa, 11.0 MPa, 11.1 MPa, 11.2 MPa, 11.3 MPa, 11.4 MPa, 11.5 MPa, 11.6 MPa, 11.7 MPa, 11.8 MPa, 11.9 MPa, 12.0 MPa, 12.1 MPa, 12.2 MPa, 12.3 MPa, 12.4 MPa, 12.5 MPa, 12.6 MPa, 12.7 MPa, 12.8 MPa, 12.9 MPa, 13.0 MPa, 13.1 MPa, 13.2 MPa, 13.3 MPa, 13.4 MPa, 13.5 MPa, 13.6 MPa, 13.7 MPa, 13.8 MPa, 13.9 MPa, 14.0 MPa, 14.1 MPa, 14.2 MPa, 14.3 MPa, 14.4 MPa, 14.5 MPa, 14.6 MPa, 14.7 MPa, 14.8 MPa, 14.9 MPa, 15.0 MPa.

[0056] In this embodiment, the holding time for controlling the static pressure device to perform static pressure treatment on the static pressure raw material can specifically be 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, 20 minutes, 21 minutes, 22 minutes, 23 minutes, 24 minutes, 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29 minutes, 30 minutes, 31 minutes, 32 minutes, 33 minutes, 34 minutes, 35 minutes, 36 minutes, 37 minutes, 38 minutes, 39 minutes, 40 minutes, 41 minutes, 42 minutes, 43 minutes, 44 minutes, 45 minutes, 46 minutes, 47 minutes, 48 minutes, 49 minutes, 50 minutes, 51 minutes, 52 minutes, 53 minutes, 54 minutes, 55 minutes, 56 minutes, 57 minutes, 58 minutes, 59 minutes, 60 minutes, 61 minutes, 62 minutes, 63 minutes, 64 minutes, 65 minutes, 66 minutes, 67 minutes, 68 minutes, 69 minutes, 70 minutes, 71 minutes, 72 minutes, 73 minutes, 74 minutes, 75 minutes, 76 minutes, 77 minutes, 78 minutes, 79 minutes, 80 minutes, 81 minutes, 82 minutes, 83 minutes, 84 minutes, 85 minutes, 86 minutes, 87 minutes, 88 minutes, 89 minutes, 90 minutes, 91 minutes, 92 minutes, 93 minutes, 94 minutes, 95 minutes, 96 minutes, 97 minutes, 98 minutes, 99 minutes, 100 minutes, 101 minutes, 102 minutes, 103 minutes, 104 minutes, 105 minutes, 106 minutes, 107 minutes, 108 minutes, 109 minutes, 110 minutes, 111 minutes, 112 minutes, 113 minutes, 114 minutes, 115 minutes, 116 minutes, 117 minutes, 118 minutes, 119 minutes, 120 minutes.

[0057] In this embodiment, the density of the obtained quartz powder block can specifically be 0.2 g / cm 3 , 0.3 g / cm 3 , 0.4 g / cm 3 , 0.5 g / cm 3 , 0.6 g / cm 3 , 0.7 g / cm 3 , 0.8 g / cm 3 , 0.9 g / cm 3 , 1.0 g / cm 3 , 1.1 g / cm 3 , 1.2 g / cm 3 , 1.3 g / cm 3 , 1.4 g / cm 3 , 1.5 g / cm3 、 1.6 g / cm 3 、 1.7 g / cm 3 、 1.8 g / cm 3 。

[0058] Further combined with Figure 2 and Figure 3 As shown, an example of a hydrostatic pressure device 10 provided by an embodiment of the present application is shown. In one embodiment, the hydrostatic pressure device 10 includes a base 11 and a plurality of hydrostatic pressure components 12 that cooperate with the base 11; the base 11 and the plurality of hydrostatic pressure components 12 cooperate to form a hydrostatic pressure cavity 100 for accommodating quartz powder, and the positions of the plurality of hydrostatic pressure components 12 relative to the base 11 are adjustable for extruding the quartz powder in the hydrostatic pressure cavity 100; the surfaces of the base 11 and the plurality of hydrostatic pressure components 12 that are in contact with the quartz powder are made of high-purity quartz material.

[0059] In this embodiment, the number of the hydrostatic pressure components 12 is five. The five hydrostatic pressure components 12 form a semi-surrounding structure and are arranged on the same side of the base 11. Among them, four hydrostatic pressure components 12 are respectively in contact with the base 11 and are arranged in a surrounding manner, and the remaining one hydrostatic pressure component 12 is arranged at an interval from the base 11 and is in contact with the aforementioned four hydrostatic pressure components 12. Each hydrostatic pressure component 12 includes a pressure rod 121, a connecting push block 122, and a quartz extrusion gasket 123. The connecting push block 122 is connected to the end of the pressure rod 121 and is used to abut against the quartz extrusion gasket 123 to push the quartz extrusion gasket 123 to move inward to compress the space volume of the hydrostatic pressure cavity 100 to achieve hydrostatic pressure; the base 11 includes a support portion 111 and a quartz bottom 112. The five quartz extrusion gaskets 123 and a quartz bottom 112 enclose to form the hydrostatic pressure cavity 100. The quartz powder is arranged in the hydrostatic pressure cavity 100 and is in contact with the quartz extrusion gaskets 123 and the quartz bottom 112. The plurality of pressure rods 121 push inward to extrude the quartz powder to form a quartz powder block 20.

[0060] It can be understood that the hydrostatic pressure device 10 is composed of five hydrostatic pressure components 12 on the front, rear, left, right, and upper sides and a base 11 embedded with a quartz plate. During operation, after the surrounding hydrostatic pressure components 12 are fixed in place, the quartz powder is evenly poured into the hydrostatic pressure cavity 100 and the quartz powder is extruded. The pressure rods 121 around can be provided with or connected to pressure sensors (not shown in the figure) to synchronously provide pressure to maintain the hydrostatic pressure components 12 in the working position. After maintaining the extrusion state for a certain period of time to make the quartz powder body combine tightly, the surrounding and upper hydrostatic pressure components 12 are removed in sequence to obtain the formed quartz powder block 20. By adjusting the height of the extruded and formed material, the density of the pressed material can be regulated.

[0061] For ease of understanding, Figure 2The base 11 and the hydrostatic pressure component 12 in it show their necessary structures in regular shapes; those skilled in the art can understand that the base 11 and the hydrostatic pressure component 12 can also be in other shapes. At the same time, the specific connection relationships between the pressure rod 121, the connecting push block 122, and the quartz extrusion gasket 123 are not limited, nor are the specific connection relationships between the support part 111 and the quartz bottom pad 112.

[0062] Furthermore, in the quartz glass preparation method provided by the embodiments of the present application using quartz powder as a raw material, a hydrostatic pressure device 10 is used to apply hydrostatic pressure to the quartz powder. The five quartz extrusion gaskets 123 and one quartz bottom pad 112 used for contacting the quartz powder in the hydrostatic pressure device 10 are all made of quartz. The quartz powder will not contact other material containers during the vitrification process, thereby avoiding the introduction of impurity ions and enabling the formed quartz product to have characteristics such as high uniformity, low stress, and low hydroxyl.

[0063] In addition, if a container is introduced to hold the quartz powder during forming, these containers can be capsules made of metal or glass. However, capsules made of metal and ordinary glass will introduce other elements and affect the performance of the quartz glass. Although capsules made of quartz glass generally do not introduce other elements, the material of the quartz glass capsules is relatively brittle and there are production hazards. Moreover, the volume of the quartz glass capsules is usually fixed and it is difficult to make adaptive adjustments according to actual production needs. However, the five quartz extrusion gaskets 123 and one quartz bottom pad 112 in the hydrostatic pressure device 10 provided by the embodiments of the present application are movably arranged, and they can adjust the volume of the hydrostatic pressure cavity 100 during the hydrostatic pressure application. On the one hand, it avoids the introduction of other impurity ions and ensures the excellent characteristics of the quartz glass. On the other hand, it makes the production process more flexible and improves the production efficiency, and further ensures the excellent characteristics of the quartz glass, making the quartz glass obtained by the embodiments of the present application have more excellent characteristics compared with conventional quartz glass products of ordinary purity.

[0064] Step S4: Place the quartz powder block in a container with a contact surface made of high-purity quartz, and vitrify the quartz powder block to obtain quartz glass.

[0065] In one embodiment, the vitrification temperature range for vitrifying the quartz powder block is 1350°C to 1500°C, and the vitrification time for vitrifying the quartz powder block is 10 hours to 90 hours.

[0066] In one embodiment, the vitrification temperature range for vitrifying the quartz powder block is 1400°C to 1480°C, and the vitrification time for vitrifying the quartz powder block is 40 hours to 60 hours.

[0067] It can be understood that the quartz powder block is placed in a quartz container with high-purity quartz sand at the bottom. The quartz container can avoid the introduction of impurities during the vitrification process, and the presence of quartz sand can effectively prevent the quartz glass from adhering to the container. Among them, the vitrification temperature range is from 1350 °C to 1500 °C, and the preferred temperature range is from 1400 °C to 1480 °C; the vitrification time is from 10 hours to 90 hours, and the preferred vitrification time is from 40 hours to 60 hours.

[0068] In this embodiment, the vitrification temperature for controlling the vitrification of the quartz powder block can specifically be 1350 °C, 1360 °C, 1370 °C, 1380 °C, 1390 °C, 1400 °C, 1410 °C, 1420 °C, 1430 °C, 1440 °C, 1450 °C, 1460 °C, 1470 °C, 1480 °C, 1490 °C, 1500 °C.

[0069] In this embodiment, the vitrification time for controlling the vitrification of the quartz powder block can specifically be 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, 30 hours, 31 hours, 32 hours, 33 hours, 34 hours, 35 hours, 36 hours, 37 hours, 38 hours, 39 hours, 40 hours, 41 hours, 42 hours, 43 hours, 44 hours, 45 hours, 46 hours, 47 hours, 48 hours, 49 hours, 50 hours, 51 hours, 52 hours, 53 hours, 54 hours, 55 hours, 56 hours, 57 hours, 58 hours, 59 hours, 60 hours, 61 hours, 62 hours, 63 hours, 64 hours, 65 hours, 66 hours, 67 hours, 68 hours, 69 hours, 70 hours, 71 hours, 72 hours, 73 hours, 74 hours, 75 hours, 76 hours, 77 hours, 78 hours, 79 hours, 80 hours, 81 hours, 82 hours, 83 hours, 84 hours, 85 hours, 86 hours, 87 hours, 88 hours, 89 hours, 90 hours.

[0070] The embodiment of the present application provides a method for preparing high-purity quartz using quartz powder as a raw material. During the whole process of transforming quartz powder into a quartz product (quartz glass), it does not come into contact with other materials, ensuring the high purity of the quartz product; at the same time, through the dehydroxylation process, non-metallic impurities (such as hydroxyl groups) in the quartz powder are controlled at an extremely low level of less than 1 ppm. Furthermore, during the preparation of high-purity quartz, the vitrification route of the VAD two-step method (one of the common routes for high-performance quartz glass) is adopted, making the quartz glass product prepared by this method have the characteristics of high uniformity and low stress.

[0071] Therefore, the method for preparing high-purity quartz using quartz powder as a raw material provided by the embodiments of the present application can obtain quartz products with high optical uniformity, low stress, low hydroxyl groups, and high purity.

[0072] The embodiments of the present application further provide a quartz product, which is obtained by the method for preparing quartz glass using quartz powder as a raw material described in any one of the foregoing embodiments.

[0073] Furthermore, the method for preparing quartz glass using quartz powder as a raw material provided by the embodiments of the present application can obtain high-purity quartz products. On the one hand, by dispersing, screening, and dehydroxylating quartz powder, the hydroxyl group content of the powder is controlled, thereby controlling the hydroxyl group content of quartz glass, and it is possible to prepare quartz glass with a hydroxyl group content of less than 1 ppm. On the other hand, a static pressure device in which all parts in contact with the quartz powder are made of quartz material is used to apply static pressure to the quartz powder, avoiding the introduction of impurities due to contact, and pressing out a quartz powder block with a specific specification and specific density. On the further hand, the present application adopts a process imitating the two-step method to prepare high-purity synthetic quartz glass in a non-molten environment, and the product has the characteristics of high purity, low hydroxyl groups, low stress, high optical uniformity, no bubbles, and no stripes.

[0074] It can be understood that the quartz products provided by the present application have more excellent properties than conventional quartz glass products with ordinary purity. The quartz products provided by the present application have the characteristic of high purity. The high-purity quartz powder selected in the present application has a purity of greater than or equal to 99.99% (4N), and preferably a purity of greater than or equal to 99.99999% (7N); the "high purity" especially refers to an ultra-high purity with a metal impurity ion ppb level (parts per billion, one in a billion) purity greater than 99.999999% (8N); at the same time, the quartz products provided by the present application also have excellent properties such as high optical uniformity, low stress, and low hydroxyl groups.

[0075] Example 1: Natural silica powder with a purity of 99.995% is used. After vibrating and screening, quartz powder particles with a particle size of 50 nanometers to 300 micrometers are selected; the vacuum is pumped to a vacuum degree of 8 Pa in a vacuum furnace, and sintered at 800 °C for 70 hours with a 2-hour temperature rise for dehydroxylation; the powder is pressed at a pressure of 5 MPa for 30 minutes to form a quartz powder block with a density of 0.7 g / cm 3 , and the three-dimensional size corresponds to a quartz powder block of 40 cm by 40 cm by 20 cm, and sintered at 1400 °C with a 10-hour temperature rise for 30 hours to obtain a quartz glass block. After processing, a quartz glass block with a three-dimensional size corresponding to 25 cm by 25 cm by 12 cm is obtained. After testing, its metal impurity content is 53 ppm; the hydroxyl group content is less than 1 ppm; there are no stripes and bubbles inside the product; the optical uniformity is 6.3×10 -6; Stress birefringence: 2.1 nm / cm.

[0076] Example 2: Natural silica powder with a purity of 99.995% is used. After vibration screening, quartz powder particles with a particle size of 100 nanometers to 200 micrometers are selected; it is pumped to a vacuum degree of 5 Pa in a vacuum furnace, and sintered at 1000 °C for 70 hours in the vacuum furnace for dehydroxylation; pressed at a pressure of 5 MPa for 25 minutes, and the powder is pressed into a quartz powder block with a density of 0.6 g / cm 3 , with three-dimensional dimensions corresponding to a quartz powder block of 40 cm by 40 cm by 20 cm, and sintered at 1450 °C for 40 hours in 10 hours to obtain a quartz glass block. After processing, a quartz glass block with three-dimensional dimensions corresponding to 25 cm by 25 cm by 12 cm is obtained. After testing, its metal impurity content is 51 ppm; the hydroxyl content is less than 1 ppm; there are no stripes or bubbles inside the product; the optical uniformity is 4.8×10 -6 ; Stress birefringence: 1.9 nm / cm.

[0077] Example 3: High-purity silica waste powder produced by deposition process with a purity higher than 99.99999% is used. After vibration screening, quartz powder particles with a particle size of 100 nanometers to 200 micrometers are selected; it is pumped to a vacuum degree of 5 Pa in a vacuum furnace, and sintered at 1000 °C for 80 hours in the vacuum furnace for dehydroxylation; pressed at a pressure of 5 MPa for 25 minutes, and the powder is pressed into a quartz powder block with a density of 0.53 g / cm 3 , with three-dimensional dimensions corresponding to a quartz powder block of 40 cm by 40 cm by 20 cm, and sintered at 1450 °C for 40 hours in 10 hours to obtain a quartz glass block. After processing, a quartz glass block with three-dimensional dimensions corresponding to 25 cm by 25 cm by 12 cm is obtained. After testing, its metal impurity content is 9.8 ppb; the hydroxyl content is less than 1 ppm; there are no stripes or bubbles inside the product; the optical uniformity is 3.9×10 -6 ; Stress birefringence: 1.5 nm / cm.

[0078] Example 4: High-purity synthetic silica powder with a purity higher than 99.999995% is used. After vibration screening, quartz powder particles with a particle size of 100 nanometers to 100 micrometers are selected; it is pumped to a vacuum degree of 1 Pa in a vacuum furnace, and sintered at 1000 °C for 60 hours in the vacuum furnace for dehydroxylation; pressed at a pressure of 8 MPa for 60 minutes, and the powder is pressed into a quartz powder block with a density of 1.2 g / cm 3, a quartz powder block with three-dimensional dimensions corresponding to 40 cm by 40 cm by 20 cm is sintered at 1500 °C for 40 hours after being heated up in 10 hours to obtain a quartz glass block. After processing, a quartz glass block with three-dimensional dimensions corresponding to 30 cm by 30 cm by 15 cm is obtained. After testing, its metal impurity content is 8.2 ppb; the hydroxyl content is less than 1 ppm; there are no stripes or bubbles inside the product; the optical uniformity is 3.6×10 -6 ; the stress birefringence is 1.9 nm / cm.

[0079] Example 5: Using high-purity synthetic silica powder with a purity higher than 99.999995%, quartz powder particles with a particle size of 1 to 100 microns are selected after vibrating and sieving; the vacuum degree is pumped to 0.1 Pa in a vacuum furnace, and it is sintered at 1100 °C for 40 hours in the vacuum furnace for dehydroxylation; it is pressed for 20 minutes under a pressure of 8 MPa to press the powder into a density of 0.58 g / cm 3 , a quartz powder block with three-dimensional dimensions corresponding to 40 cm by 40 cm by 40 cm is sintered at 1480 °C for 60 hours after being heated up in 20 hours to obtain a quartz glass block. After processing, a quartz glass block with three-dimensional dimensions corresponding to 20 cm by 20 cm by 20 cm is obtained. After testing, its metal impurity content is 5.9 ppb; the hydroxyl content is less than 1 ppm; there are no stripes or bubbles inside the product; the optical uniformity is 3.4×10 -6 ; the stress birefringence is 1.1 nm / cm.

[0080] In the above text, the specific embodiments of the present application are described with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that various changes and substitutions can be made to the specific embodiments of the present application without departing from the scope of the present application. These changes and substitutions all fall within the scope defined by the present application.

Claims

1. A method for preparing quartz glass using quartz powder as a raw material, characterized in that, It includes the following steps: Provide quartz powder as the initial raw material; Perform pretreatment on the initial raw material to obtain a static pressure raw material containing quartz powder. The pretreatment includes at least a process of screening the initial raw material and a process of dehydroxylation of the initial raw material. By the process of screening the initial raw material, silica microparticles with a particle size of 50 nanometers to 300 micrometers are obtained, and the quartz powder is dehydroxylated under a vacuum state with a vacuum degree less than 10 Pa and a temperature state with a dehydroxylation temperature of 500°C to 1300°C; Transfer the static pressure raw material to a static pressure device for static pressure treatment to obtain a quartz powder block. The parts of the static pressure device that come into contact with the quartz powder are all made of quartz material, and control the static pressure applied by the static pressure device to the static pressure raw material to be 2 MPa to 15 MPa; Place the quartz powder block in a container with a contact surface of high-purity quartz, and vitrify the quartz powder block to obtain quartz glass. The purity of the high-purity quartz is greater than or equal to 99.99%.

2. The method for preparing quartz glass using quartz powder as raw material according to claim 1, characterized in that, The process of screening the initial raw material includes: Vibrate and screen the quartz powder using a sieve to obtain the silica microparticles.

3. The method for preparing quartz glass using quartz powder as a raw material according to claim 2, characterized in that, The particle size of the silica microparticles is 100 nanometers to 200 micrometers.

4. The method for preparing quartz glass using quartz powder as a raw material according to claim 1, characterized in that, The process of dehydroxylation of the initial raw material includes: Place the quartz powder in a dehydroxylation furnace, and evacuate the inside of the dehydroxylation furnace to the vacuum state; Heat the quartz powder in the dehydroxylation furnace to remove the hydroxyl groups inside the quartz powder, and control the dehydroxylation holding time for the dehydroxylation of the dehydroxylation furnace to be 10 hours to 100 hours.

5. The method for preparing quartz glass using quartz powder as a raw material according to claim 4, characterized in that, Control the vacuum degree inside the dehydroxylation furnace to be less than 1 Pa; Control the dehydroxylation temperature for the dehydroxylation of the dehydroxylation furnace to be 700°C to 1100°C, and control the dehydroxylation holding time for the dehydroxylation of the dehydroxylation furnace to be 40 hours to 80 hours.

6. The method for preparing quartz glass using quartz powder as a raw material according to claim 1, characterized in that, The holding time for controlling the static pressure device to perform static pressure treatment on the static pressure raw material is 5 minutes to 120 minutes; controlling the density of the quartz powder block obtained by performing static pressure treatment in the static pressure device to be 0.2 g / cm 3 to 1.8 g / cm 3 .

7. The method for preparing quartz glass using quartz powder as a raw material according to claim 6, characterized in that, The static pressure of the static pressure device for static pressure treatment of the static pressure raw material is controlled to be 5 MPa to 10 MPa, and the pressure holding time of the static pressure device for static pressure treatment of the static pressure raw material is controlled to be 30 minutes to 60 minutes; the density of the quartz powder block obtained by static pressure treatment in the static pressure device is controlled to be 0.5 g / cm 3 to 0.6 g / cm 3 .

8. The method for preparing quartz glass using quartz powder as a raw material according to claim 1, characterized in that, The static pressure device includes a base and a plurality of static pressure components that cooperate with the base; The base and the plurality of static pressure components cooperate to form a static pressure cavity for accommodating the quartz powder. The positions of the plurality of static pressure components are adjustable relative to the base for squeezing the quartz powder in the static pressure cavity; The surfaces of the base and the plurality of static pressure components that come into contact with the quartz powder are all made of the high-purity quartz material.

9. The method for preparing quartz glass using quartz powder as a raw material according to claim 1, wherein, Control the vitrification temperature range for vitrifying the quartz powder block to be 1350°C to 1500°C, and control the vitrification time for vitrifying the quartz powder block to be 10 hours to 90 hours.

10. The method for preparing quartz glass using quartz powder as a raw material according to claim 9, characterized in that, Control the vitrification temperature range for vitrifying the quartz powder block to be 1400°C to 1480°C, and control the vitrification time for vitrifying the quartz powder block to be 40 hours to 60 hours.

11. A quartz product, characterized in that, The quartz product is obtained by the method for preparing quartz glass using quartz powder as the raw material according to any one of claims 1 to 10.

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