Non-transparent quartz glass and method for producing the same

Abstract

This invention discloses an opaque quartz glass and its preparation method. The preparation method includes: using an induction heating furnace, with a protective atmosphere inside the furnace that does not participate in the reaction, and a protective atmosphere pressure of 10000–90000 Pa; placing quartz sand in the induction heating furnace, first heating it to 1400–1570℃ to preheat the quartz sand; then heating it to 1650–1710℃ at a rate not exceeding 0.2℃ / s to ensure uniform heating of the quartz sand; then heating it to 1740–1900℃ at a rate not less than 0.2℃ / s to bring the quartz sand to its melting temperature and sintering it; finally cooling it at a rate not exceeding 2℃ / s to obtain the opaque quartz glass. The density of the opaque quartz glass is 0.9–2.19 g / cm³. 3 When the bubble size is 1-300μm and the thickness is 2mm, the transmittance in the 380-3000nm band is less than 20%; when the thickness is 5mm, the transmittance in the 380-3000nm band is less than 3%; and the hardness is 1000-6900MPa.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of opaque quartz glass, in particular to a preparation method of opaque quartz glass and the product thereof. BACKGROUND

[0002] Quartz glass has a wide range of applications in the fields of semiconductor, aerospace, optical communication, photovoltaic, biomedical and electronics due to its unique physical and chemical properties, such as high temperature resistance, ablation resistance and electrical insulation.

[0003] Glass with a large number of micron-sized bubbles uniformly distributed in the quartz glass is called opaque quartz glass. Opaque quartz glass not only has outstanding excellent performance in purity, heat, chemical corrosion resistance and other aspects of ordinary quartz glass, but also has unique heat insulation performance. In the manufacturing equipment of semiconductor, photovoltaic and other fields, opaque quartz glass is used for heating components such as flanges and core tubes, which can increase the scattering of thermal radiation lines inside the material and effectively prevent heat loss. In addition, opaque quartz glass with high chemical stability has the potential to be applied in the field of biological implantation by adjusting its density and pore size to simulate the stiffness and strength of human bones.

[0004] The preparation of opaque quartz glass is mainly realized by the following methods:

[0005] 1. A small amount of inorganic or organic pore-forming agent (such as silicon nitride, carbon powder, polysiloxane and white carbon black, polystyrene powder) is added to the quartz sand raw material, and the mixed raw material is melted by hydrogen-oxygen flame (for example, patent literatures 1-3). However, this method not only reduces the purity of the product, but also has high preparation cost. At the same time, the pore-forming powder is easy to agglomerate and cannot be fully and uniformly mixed with the quartz sand, resulting in large pore diameter and poor mechanical strength and light shielding performance.

[0006] 2. After crushing, ball milling and wet granulation of the quartz sand raw material, hydrogen-oxygen flame or vacuum melting is used (for example, patent literature 4). However, wet granulation will introduce a large amount of impurities during the preparation process, resulting in high hydroxyl content in the product.

[0007] 3. Without adding a foaming agent, the heat treatment is interrupted before the quartz sand is completely densified, and partial sintering is performed (for example, patent literature 5). However, interrupting the heat treatment makes it difficult to form spherical bubbles, which reduces the mechanical strength of the product.

[0008] Existing patent technical literatures:

[0009] Patent literature 1: Japanese patent No. 3043032;

[0010] Patent literature 2: Japanese patent No. 6666464;

[0011] Patent Literature 3: Japanese Patent No. 6676826;

[0012] Patent Literature 4: CN116648436A;

[0013] Patent Literature 5: Japanese Patent No. 3394323. SUMMARY

[0014] The present application provides an opaque quartz glass and a preparation method thereof. The preparation method of the present application is an induction heating method, which can widely control the density and bubble size of the opaque quartz glass product. The opaque quartz glass prepared by the method has the advantages of good heat insulation performance, low production cost, and low content of hydroxyl and impurities. The preparation method has the characteristics of short time consumption and low energy consumption.

[0015] [1] A preparation method of an opaque quartz glass, comprising:

[0016] An induction heating furnace is used, and the atmosphere in the furnace is a protective atmosphere that does not participate in the reaction. The pressure of the protective atmosphere is 10000-90000 Pa, such as 20000 Pa, 35000 Pa, 45000 Pa, 50000 Pa, 55000 Pa, 60000 Pa, 75000 Pa, etc.

[0017] The quartz sand is placed in the induction heating furnace, and is first heated to 1400-1570℃ (such as 1400℃, 1480℃, 1490℃, 1510℃, 1500℃, etc., close to the β-cristobalite transition temperature) for preheating. Then, the quartz sand is heated to 1650-1710℃ (such as 1680℃, 1690℃, 1700℃, etc.) at a rate of not more than 0.2℃ / s (such as 0.002℃ / s, 0.005℃ / s, 0.041℃ / s, 0.042℃ / s, 0.052℃ / s, 0.067℃ / s, 0.19℃ / s, etc.) to uniformly heat the quartz sand. Then, the quartz sand is heated to 1740-1900℃ (such as 1750℃, 1760℃, etc.) at a rate of not less than 0.2℃ / s (such as 0.27℃ / s, 0.33℃ / s, 0.30℃ / s, 0.40℃ / s, 0.45℃ / s, 0.50℃ / s, 1℃ / s, etc.) to reach the melting temperature and sintering. Finally, the quartz sand is cooled at a rate of not more than 2℃ / s (such as 0.7℃ / s, 0.9℃ / s, 1℃ / s, 1.2℃ / s, etc.) to obtain the opaque quartz glass.

[0018] The present application uses a lower pressure (10000-90000 Pa) rather than vacuum, which can always maintain the bubbles in the glass.

[0019] The preparation method of the present application slows the heating rate before the quartz glass forming temperature, and accelerates the heating rate after the quartz sand particles are fully preheated, so that the heating is uniform, and the bubble growth becomes spherical. By adjusting the heating curve, the bubble diameter and the number of bubbles can be controlled, thereby achieving the purpose of density adjustment.

[0020] Specifically, the slow heating to 1650-1710 DEG C is to make the quartz sand heat uniformly, and in this process, the quartz sand reaches the critical point of impending melting, but always remains in the unmelting state; then the rapid heating to 1740-1900 DEG C is because at the temperature of 1740-1900 DEG C, the quartz sand melts and begins to sink and densify, and the rapid heating speed is to keep as many of these interstitial bubbles as possible, so that they cannot escape (before escaping, they are wrapped in the glass solution), if the heating speed is slow, many bubbles will be pushed away by the sinking glass liquid, and the rapid heating speed, the large viscosity of quartz, can make the bubbles not be pushed out in time.

[0021] In some embodiments, the preparation method of the opaque quartz glass of [1] can include a nitrogen atmosphere and / or a rare gas (such as helium and / or argon, etc.) atmosphere.

[0022] In some embodiments, the preparation method of the opaque quartz glass of [1] can have a total heating time of not more than 5h.

[0023] In some embodiments, the preparation method of the opaque quartz glass of [1] can be dried before being placed in the induction heating furnace.

[0024] In some embodiments, the preparation method of the opaque quartz glass of [1] can be ultrasonic and / or vibration operated before being placed in the induction heating furnace, so that the quartz sand is densely packed and no "bridge" gap is generated, which is beneficial to avoid the size of the bubbles in the final opaque quartz glass product being too large.

[0025] In some embodiments, the preparation method of the opaque quartz glass of [1] can have a quartz sand size of 40-200 mesh, such as 80-100 mesh, 80-120 mesh, 80-200 mesh, 120-200 mesh, 40-80 mesh, 180-200 mesh, etc. The quartz sand of the above mesh size has certain gaps when it is packed, and these gaps will be converted into bubbles of the required size during sintering.

[0026] In the preparation method, the quartz sand is first heated to 1400-1570°C after being placed in the induction heating furnace. The terminal temperature of the heating process in this stage affects the maximum size of the bubbles in the final opaque quartz glass product. The higher the terminal temperature, the smaller the maximum size of the bubbles in the opaque quartz glass product. The lower the terminal temperature, the larger the maximum size of the bubbles in the opaque quartz glass product.

[0027] In some embodiments, the preparation method of the opaque quartz glass in [1] can first heat the quartz sand to 1400-1570°C at a rate of not less than 0.3°C / s (for example, 0.4°C / s, 0.48°C / s, 0.49°C / s, 0.5°C / s, 0.51°C / s, 0.6°C / s, 0.8°C / s, 1°C / s, etc.) for preheating.

[0028] In some embodiments, the preparation method of the opaque quartz glass in [1] can heat the quartz sand to 1400-1570°C for 3-30 min (for example, 5 min, 8 min, 10 min, 15 min, etc.) for preheating.

[0029] In some embodiments, the preparation method of the opaque quartz glass in [1] can first heat the quartz sand to 1000°C at a rate of not less than 0.3°C / s (for example, 0.5°C / s, 0.8°C / s, 1°C / s, etc.), and then heat to 14400-1570°C at a rate of 0.3-0.6°C / s (for example, 0.4°C / s, 0.48°C / s, 0.49°C / s, 0.5°C / s, 0.51°C / s, 0.6°C / s, etc.) for 3-30 min for preheating. Further, multiple heating gradients can be set during the heating to 1000°C, for example, stopping at one or more temperature points for a period of time, and then continuing to heat.

[0030] In the preparation method, the terminal temperature of the heating process in this stage affects the maximum size of the bubbles in the final opaque quartz glass product. The higher the terminal temperature, the larger the maximum size of the bubbles in the opaque quartz glass product. The lower the terminal temperature, the smaller the maximum size of the bubbles in the opaque quartz glass product.

[0031] In some embodiments, the preparation method of the opaque quartz glass in [1] can heat the quartz sand to 1650-1710°C at a rate of 0.002-0.2°C / s for uniform heating.

[0032] In the preparation method, the heating rate during the process of heating to 1740-1900℃ will affect the density of the final opaque quartz glass. The faster the heating rate, the smaller the density of the final opaque quartz glass. The slower the heating rate, the greater the density of the final opaque quartz glass. In the preparation method, the heating rate during the process of heating to 1740-1900℃ is preferably not less than 0.2℃ / s, and can be further preferably 0.2-1℃ / s.

[0033] In the preparation method, after heating to 1740-1900℃, it is preferred to keep the temperature for a period of time. The length of the holding time will affect the density of the final opaque quartz glass. The longer the holding time, the smaller the density of the final opaque quartz glass. The shorter the holding time, the greater the density of the final opaque quartz glass. In the preparation method, after heating to 1740-1900℃, it is preferred to keep the temperature for 5-20min, for example, 8min, 10min, 15min, etc. That is, in some embodiments, the preparation method of the opaque quartz glass in [1] can heat to 1740-1900℃ and keep the temperature for 5-20min, so that the quartz sand reaches the melting temperature and is sintered.

[0034] In some embodiments, the preparation method of the opaque quartz glass in [1] can heat to 1740-1900℃ at a rate of 0.2-1℃ / s, keep the temperature for 5-20min, so that the quartz sand reaches the melting temperature and is sintered.

[0035] In the preparation method, the final cooling rate will affect the transparency of the final opaque quartz glass product. Reducing the cooling rate can reduce the transmittance of the final opaque quartz glass, increase the opaque degree of the final opaque quartz glass, and increasing the cooling rate can increase the transmittance of the final opaque quartz glass, reduce the opaque degree of the final opaque quartz glass. In the preparation method, it is preferred to cool at a rate of not more than 2℃ / s to obtain the opaque quartz glass.

[0036] In some preferred examples, the preparation method of the opaque quartz glass in [1] can cool at a rate of 0.2-2℃ / s.

[0037] In some embodiments, the preparation method of the opaque quartz glass in [1] can have a room temperature as the final cooling point to obtain the opaque quartz glass.

[0038] In some embodiments, the preparation method of the opaque quartz glass in [1] can use a graphite crucible to hold the quartz sand and place it in the induction heating furnace. Further, a release layer can be provided between the graphite crucible and the quartz sand. The release layer has high temperature resistance, and its setting method can be coating, placement, etc.

[0039] [2] The opaque quartz glass prepared by the preparation method of [1].

[0040] In some embodiments, the opaque quartz glass has a density of 0.9-2.19 g / cm 3 , further 1.1-2.19 g / cm 3 , for example 1.138 g / cm 3 , 1.327 g / cm 3 , 1.417 g / cm 3 , 1.719 g / cm 3 , 1.883 g / cm 3 , 1.964 g / cm 3 , 1.990 g / cm 3 , 2.141 g / cm 3 , etc.

[0041] In some embodiments, the opaque quartz glass has a bubble size of 1-300 μm, further 10-200 μm.

[0042] In some embodiments, the opaque quartz glass has a transmittance of less than 20%, further less than 8%, in the wavelength range of 380-3000 nm when the thickness is 2 mm.

[0043] In some embodiments, the opaque quartz glass has a transmittance of less than 3%, further less than 2%, in the wavelength range of 380-3000 nm when the thickness is 5 mm.

[0044] In some embodiments, the opaque quartz glass has a hardness of 1000-6900 MPa, further 1700-6900 MPa.

[0045] Compared with the prior art, the present application has the following beneficial effects:

[0046] The density of the opaque quartz glass prepared by the present application can be adjusted in the range of 0.9-2.19 g / cm 3 , the quartz glass product is easy to be processed and shaped, and can meet the high physical and chemical stability required by biological implantation, and the microporous structure in the opaque quartz glass can also provide a substrate for the growth of biological factors.

[0047] The present application uses induction heating method to prepare the opaque quartz glass, solves the problem of high hydroxyl group caused by hydrogen-oxygen flame sintering, at the same time, only uses quartz sand as raw material, ensures the purity of the glass matrix, and the product prepared by using high-purity quartz sand as raw material can be applied to the semiconductor process flow, in addition, the heating time required by the method is short, the preparation speed is fast, and the energy consumption is low. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 The transmittance spectrum of the 2mm opaque quartz glass sample of Example 1#, Example 2#, Example 3#, Example 4# of the present application.

[0049] Figure 2 The 2mm section physical photograph of Example 3# of the present application.

[0050] Figure 3 The transmittance spectrum of the 5mm opaque quartz glass sample of Example 3#, Example 6# of the present application. DETAILED DESCRIPTION

[0051] The present application will be further described below in conjunction with the accompanying drawings and specific examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application.

[0052] Example 1#:

[0053] First, the quartz sand raw material with particle size of 80-100 mesh is placed into a vacuum drying oven for heating and drying, the drying temperature is 100℃, and the drying time is 24h; 30g of the dried quartz sand raw material is placed into a graphite crucible, and the graphite crucible with the raw material is subjected to ultrasonic, the ultrasonic frequency is 40kHZ, and the ultrasonic time is 4h; the graphite crucible with the raw material is placed into an induction heating furnace for melting under argon atmosphere, the temperature rising program is as follows: from room temperature to 400℃ at 1℃ / s, holding for 5min, then to 800℃ at 1℃ / s, holding for 5min, then to 1000℃ at 0.8℃ / s, holding for 10min; then, to 1480℃ at 0.48℃ / s, holding for 5min, for preheating of the quartz sand; then, slowly to 1690℃ at 0.042℃ / s, for uniform heating of the quartz sand; then, to 1750℃ at 0.33℃ / s, holding for 10min, for the quartz sand to rapidly reach the melting temperature and sintering; finally, to room temperature at 1℃ / s. The protection atmosphere pressure is kept at 55000Pa during the melting process, and the opaque quartz glass is obtained after the process, the density of which is measured to be 1.417g / cm 3 , and the 2mm thickness sample is obtained after cutting, grinding and polishing, the hardness of which is 3231MPa, the bubble size distribution is 30-170μm, and the transmittance spectrum of the sample is shown in Figure 1 .

[0054] Example 2#:

[0055] Firstly, the quartz sand raw material with particle size of 80-100 mesh is placed into a vacuum drying oven for heating and drying, the drying temperature is 150℃, and the drying time is 20h; 30g of the dried quartz sand raw material is placed into a graphite crucible, and the graphite crucible with the raw material is subjected to ultrasonic treatment, the ultrasonic frequency is 40kHZ, and the ultrasonic time is 2h; the graphite crucible with the raw material is placed into an induction heating furnace, and is subjected to melting under an argon atmosphere, the temperature rising program is as follows: from room temperature to 500℃ at a rate of 1℃ / s, and then kept for 5min, then to 1000℃ at a rate of 0.8℃ / s, and then kept for 10min; then, the temperature is slowly raised to 1490℃ at a rate of 0.49℃ / s, and then kept for 5min, so as to preheat the quartz sand; then, the temperature is slowly raised to 1700℃ at a rate of 0.052℃ / s, so as to uniformly heat the quartz sand; then, the temperature is rapidly raised to 1740℃ at a rate of 0.27℃ / s, and then kept for 10min, so as to rapidly reach the melting temperature and sinter the quartz sand; finally, the temperature is reduced to room temperature at a rate of 2℃ / s. During the melting process, the pressure of the protective atmosphere is kept at 50000Pa, and then the opaque quartz glass is obtained, the density of which is 1.719g / cm 3 , and then a 2mm-thick sample is obtained after cutting, grinding and polishing. The hardness is 5389MPa, the bubble size distribution is 40-130μm, and the transmittance spectrum of the sample is shown in Figure 1 .

[0056] Example 3:

[0057] Firstly, the quartz sand raw material with particle size of 80-100 mesh is placed into a vacuum drying oven for heating and drying, the drying temperature is 100℃, and the drying time is 15h; 40g of the dried quartz sand raw material is placed into a graphite crucible, and the graphite crucible with the raw material is subjected to ultrasonic treatment, the ultrasonic frequency is 20kHZ, and the ultrasonic time is 5h; the graphite crucible with the raw material is placed into an induction heating furnace, and is subjected to melting under an argon atmosphere, the temperature rising program is as follows: from room temperature to 800℃ at a rate of 1℃ / s, and then kept for 10min, then to 1000℃ at a rate of 0.5℃ / s, and then kept for 20min; then, the temperature is slowly raised to 1510℃ at a rate of 0.51℃ / s, and then kept for 10min, so as to preheat the quartz sand; then, the temperature is slowly raised to 1700℃ at a rate of 0.067℃ / s, so as to uniformly heat the quartz sand; then, the temperature is rapidly raised to 1740℃ at a rate of 0.30℃ / s, and then kept for 10min, so as to rapidly reach the melting temperature and sinter the quartz sand; finally, the temperature is reduced to room temperature at a rate of 0.7℃ / s. During the melting process, the pressure of the protective atmosphere is kept at 35000Pa, and then the opaque quartz glass is obtained, the density of which is 1.964g / cm 3 , and then a 2mm-thick sample is obtained after cutting, grinding and polishing, as shown in Figure 2The hardness is 5846 MPa, the bubble size distribution is 30-120 μm, and the transmittance spectrum of the sample is shown in Fig. 4. Figure 1 The 5 mm thick sample is obtained by cutting, grinding and polishing, and the transmittance spectrum of the sample is shown in Fig. 4. Figure 3

[0058] Example 4#:

[0059] First, the quartz sand raw material with a particle size of 80-120 mesh is placed in a vacuum drying oven for heating and drying, the drying temperature is 130°C, and the drying time is 24 h; 35 g of the dried quartz sand raw material is placed in a graphite crucible, the graphite crucible with the raw material is subjected to ultrasonic treatment, the ultrasonic frequency is 40 kHz, and the ultrasonic time is 7 h; the graphite crucible with the raw material is placed in an induction heating furnace, and is subjected to melting under an argon atmosphere, the temperature rising program is as follows: from room temperature to 400°C at a rate of 0.5°C / s, holding for 5 min, then to 800°C at a rate of 0.8°C / s, holding for 5 min, then to 1000°C at a rate of 0.8°C / s, holding for 10 min; then, the quartz sand is preheated by increasing the temperature to 1500°C at a rate of 0.48°C / s, holding for 5 min; then, the quartz sand is uniformly heated by increasing the temperature to 1700°C at a rate of 0.067°C / s; then, the quartz sand is rapidly heated to 1740°C at a rate of 0.3°C / s, holding for 10 min, so that the quartz sand rapidly reaches the melting temperature and is sintered; finally, the temperature is decreased to room temperature at a rate of 0.9°C / s. During the melting process, the pressure of the protective atmosphere is maintained at 45000 Pa, and after the process is completed, the opaque quartz glass is obtained, and the density thereof is measured to be 1.883 g / cm 3 The 2 mm thick sample is obtained by cutting, grinding and polishing, the hardness is 5671 MPa, the bubble size distribution is 60-100 μm, and the transmittance spectrum of the sample is shown in Fig. 4. Figure 1

[0060] Example 5#:

[0061] ​​Firstly, the quartz sand raw material with particle size of 80-200 mesh is put into a vacuum drying oven for heating and drying, the drying temperature is 150℃, and the drying time is 12h; 50g of the dried quartz sand raw material is put into a graphite crucible, and the graphite crucible with the raw material is subjected to ultrasonic treatment, the ultrasonic frequency is 30kHZ, and the ultrasonic time is 5h; the graphite crucible with the raw material is put into an induction heating furnace, and is subjected to melting under an argon atmosphere, the temperature rising program is as follows: from room temperature to 400℃ at a rate of 0.5℃ / s, holding for 3min, then to 1000℃ at a rate of 0.5℃ / s, holding for 10min; then, the temperature is raised to 1400℃ at a rate of 0.6℃ / s, holding for 15min, for preheating of the quartz sand; then, the temperature is slowly raised to 1710℃ at a rate of 0.002℃ / s, for uniform heating of the quartz sand; then, the temperature is rapidly raised to 1750℃ at a rate of 0.4℃ / s, holding for 5min, for the quartz sand to rapidly reach the melting temperature and sintering; finally, the temperature is lowered to room temperature at a rate of 2℃ / s. During the melting process, the pressure of the protective atmosphere is kept at 60000Pa, and after the process is completed, the opaque quartz glass is obtained, and the density thereof is measured to be 1.327g / cm 3 After cutting, polishing and polishing, a 2mm thick sample is obtained, the hardness is 2554MPa, the bubble size distribution is 30-160μm, and the transmittance of the sample is less than 1% in the wavelength range of 300-3800nm.

[0062] Example 6#

[0063] Firstly, the quartz sand raw material with particle size of 100-120 mesh is put into a vacuum drying oven for heating and drying, the drying temperature is 100℃, and the drying time is 24h; 25g of the dried quartz sand raw material is put into a graphite crucible, and the graphite crucible with the raw material is subjected to ultrasonic treatment, the ultrasonic frequency is 40kHZ, and the ultrasonic time is 6h; the graphite crucible with the raw material is put into an induction heating furnace, and is subjected to melting under an argon atmosphere, the temperature rising program is as follows: from room temperature to 400℃ at a rate of 1℃ / s, holding for 5min, then to 800℃ at a rate of 1℃ / s, holding for 10min, then to 1000℃ at a rate of 0.8℃ / s, holding for 10min; then, the temperature is raised to 1510℃ at a rate of 0.5℃ / s, holding for 8min, for preheating of the quartz sand; then, the temperature is slowly raised to 1700℃ at a rate of 0.067℃ / s, for uniform heating of the quartz sand; then, the temperature is rapidly raised to 1740℃ at a rate of 0.27℃ / s, holding for 8min, for the quartz sand to rapidly reach the melting temperature and sintering; finally, the temperature is lowered to room temperature at a rate of 1.2℃ / s. During the melting process, the pressure of the protective atmosphere is kept at 50000Pa, and after the process is completed, the opaque quartz glass is obtained, and the density thereof is measured to be 1.990g / cm 3, the sample with a thickness of 2 mm is obtained after cutting, grinding and polishing, the hardness is 5893 MPa, the bubble size distribution is 40-125 μm, and the transmittance of the sample is less than 7% in the wavelength range of 300-3800 nm. Figure 3

[0064] Example 7:

[0065] First, the quartz sand raw material with a particle size of 40-80 mesh is placed in a vacuum drying oven for heating and drying, the drying temperature is 120°C, and the drying time is 10 h; 50 g of the dried quartz sand raw material is placed in a graphite crucible, the graphite crucible with the raw material is subjected to ultrasonic treatment, the ultrasonic frequency is 30 kHz, and the ultrasonic time is 5 h; the graphite crucible with the raw material is placed in an induction heating furnace, and is subjected to melting under an argon atmosphere, the temperature rising program is as follows: from room temperature to 1000°C at a rate of 1°C / s, and kept for 30 min; then, the temperature is raised to 1400°C at a rate of 0.40°C / s, and kept for 10 min to preheat the quartz sand; then, the temperature is slowly raised to 1710°C at a rate of 0.041°C / s to uniformly heat the quartz sand; then, the temperature is rapidly raised to 1760°C at a rate of 0.5°C / s, and kept for 15 min to make the quartz sand quickly reach the melting temperature and sinter; finally, the temperature is reduced to room temperature at a rate of 1°C / s. The pressure of the protective atmosphere during the melting process is kept at 20000 Pa, and the opaque quartz glass is obtained after the process is completed, the density of which is 1.138 g / cm 3 , the sample with a thickness of 2 mm is obtained after cutting, grinding and polishing, the hardness is 5893 MPa, the bubble size distribution is 40-125 μm, and the transmittance of the sample is less than 7% in the wavelength range of 300-3800 nm.

[0066] Example 8:

[0067] ​Firstly, the quartz sand raw material with particle size of 180-200 mesh is placed into a vacuum drying oven for heating and drying, the drying temperature is 130℃, and the drying time is 24h; 40g of the dried quartz sand raw material is placed into a graphite crucible, and the graphite crucible with the raw material is subjected to ultrasonic treatment, the ultrasonic frequency is 20kHz, and the ultrasonic time is 5h; the graphite crucible with the raw material is placed into an induction heating furnace for melting under an argon atmosphere, the temperature rising program is as follows: from room temperature to 300℃ at a rate of 1℃ / s, holding for 5min, then to 500℃ at a rate of 1℃ / s, holding for 10min, then to 1000℃ at a rate of 0.8℃ / s, holding for 5min; then, to 1490℃ at a rate of 0.49℃ / s, holding for 15min, for preheating of the quartz sand; then, slowly to 1680℃ at a rate of 0.19℃ / s, for uniform heating of the quartz sand; then, to 1740℃ at a rate of 0.45℃ / s, holding for 10min, for the quartz sand to rapidly reach the melting temperature and sintering; finally, to room temperature at a rate of 1℃ / s. During the melting process, the pressure of the protective atmosphere is kept at 75000Pa, and after the process is completed, the opaque quartz glass is obtained, the density of which is measured to be 2.141g / cm 3 After cutting, grinding and polishing, a sample with a thickness of 2mm is obtained, the hardness of which is 5970MPa, the bubble size distribution is 10-60μm, and the transmittance of the sample is less than 8% in the wavelength range of 300-3800nm.

[0068] In addition, it should be understood that, after reading the above description of the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope defined by the claims attached hereto.

Claims

1. A method of producing an opaque quartz glass, characterized by, The preparation method comprises the following steps: The induction heating furnace is used, and the atmosphere in the furnace is a protective atmosphere which does not participate in the reaction, and the pressure of the protective atmosphere is 10000-90000 Pa; The quartz sand is placed in the induction heating furnace, heated to 1400-1570 DEG C first, preheats the quartz sand, then heated to 1650-1710 DEG C at a rate of no more than 0.2 DEG C / s, makes the quartz sand heat evenly, then heated to 1740-1900 DEG C at a rate of no less than 0.2 DEG C / s, makes the quartz sand reach the melting temperature and sinter, finally, cools down at a rate of no more than 2 DEG C / s, gets the opaque quartz glass, the density of the opaque quartz glass is 0.9-2.19 g / cm 3 , the bubble size is 1-300 μm, the transmittance of 380-3000 nm band is less than 20% when the thickness is 2 mm, the transmittance of 380-3000 nm band is less than 3% when the thickness is 5 mm, the hardness is 1000-6900 MPa. The total heating time in the preparation method is not more than 5 h.

2. The production method according to claim 1, characterized by, The protective atmosphere comprises a nitrogen atmosphere and / or a rare gas atmosphere.

3. The preparation method according to claim 1, characterized in that, Before the quartz sand is placed in the induction heating furnace, a drying operation is performed; Before the quartz sand is placed in the induction heating furnace, an ultrasonic and / or vibration operation is performed; The size of the quartz sand placed in the induction heating furnace is 40-200 mesh.

4. The production method according to claim 1, characterized by, After the quartz sand is placed in the induction heating furnace, the quartz sand is preheated by being heated at a rate of not less than 0.3 ℃ / s to 1400-1570 ℃.

5. The method of claim 1, wherein, After the quartz sand is placed in the induction heating furnace, the quartz sand is preheated by being heated at a rate of not less than 0.3 ℃ / s to 1000 ℃, and then heated at a rate of 0.3-0.6 ℃ / s to 1400-1570 ℃, and kept for 3-30 min.

6. The method of claim 1, wherein, Heated at a rate of 0.002-0.2 ℃ / s to 1650-1710 ℃.

7. The preparation method according to claim 1, characterized in that, Heated at a rate of 0.2-1 ℃ / s to 1740-1900 ℃, and kept for 5-20 min, so that the quartz sand reaches a melting temperature and is sintered.

8. The method of claim 1, wherein, Heated at a rate of 0.2-2 ℃ / s to room temperature, and an opaque quartz glass is obtained.

9. The method of claim 1, wherein, The graphite crucible is used to hold the quartz sand, and the graphite crucible is placed in the induction heating furnace. A release layer is arranged between the graphite crucible and the quartz sand.

10. The opaque quartz glass prepared by the preparation method in any one of claims 1-9.

11. The non-transparent quartz glass according to claim 10, characterized in that The density of the opaque quartz glass is 1.1-2.19 g / cm 3 The bubble size is 10-200 μm, the transmittance in the 380-3000 nm band is less than 8% when the thickness is 2 mm, the transmittance in the 380-3000 nm band is less than 2% when the thickness is 5 mm, and the hardness is 1700-6900 MPa.

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