High-purity quartz lump, its preparation method and application

Abstract

The application discloses high-purity quartz lumps and a preparation method and application thereof, and relates to the technical field of quartz lumps, wherein artificial high-purity quartz sand is used as a raw material, and the quartz lumps prepared by the application have better quality compared with quartz lumps prepared by using natural quartz sand; the total content of impurity elements is less than 2ppm, the content of a single impurity element is less than 1ppm, the transmittance at a 165nm deep ultraviolet band is greater than 80%, the content of hydroxyl is less than 30ppm, and there are no bubbles and air lines; compared with a method for preparing quartz lumps by using silicon tetrachloride as a raw material, the preparation method of the quartz lumps is more environmentally friendly.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of quartz ingot, in particular to a high-purity quartz ingot and a preparation method and application thereof. BACKGROUND

[0002] Quartz ingot is an important basic blank for producing and manufacturing quartz products with various shapes such as tubes, rods and plates. The development of quartz glass technology for electronic information industry is mainly reflected in the improvement of manufacturing level and product grade. In recent years, the electronic information industry application market has put forward higher performance requirements for the required quartz products, so the quartz ingot technology is also developing towards high purity.

[0003] There are mainly two kinds of preparation methods for quartz ingot at present. One is to use natural high-purity quartz as raw material and prepare it by plasma melting and gas refining. The other is to use silicon tetrachloride as raw material and prepare it by gas phase method. The first method cannot further improve the transmittance, hydroxyl content and bubble gas line of quartz glass ingot because a certain amount of impurities and inclusions exist in natural high-purity quartz sand, even if they are treated by physical and chemical methods. Moreover, the domestic high-purity quartz sand reserves are less and need to be imported in large quantities. The second method uses silicon tetrachloride as raw material, which is high in cost and causes serious environmental pollution. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a high-purity quartz ingot and a preparation method thereof, so as to use artificial high-purity quartz sand as raw material, so that the total content of impurity elements in the obtained quartz ingot is less than 2ppm, the content of single impurity element is less than 1ppm, the transmittance at 165nm deep ultraviolet band is greater than 80%, the hydroxyl content is less than 30ppm, and there is no bubble and gas line.

[0005] The technical problem to be solved by the present application is solved by the following technical scheme:

[0006] One of the purposes of the present application is to provide a preparation method of high-purity quartz ingot, which uses artificial high-purity quartz sand as raw material.

[0007] The second purpose of the present application is to provide a high-purity quartz ingot obtained by the aforementioned preparation method of high-purity quartz ingot.

[0008] The third purpose of the present application is to provide the application of the high-purity quartz ingot in the production of quartz tubes, quartz rods and quartz plates.

[0009] The present application has the following advantages: compared with the quartz ingot prepared by using natural quartz sand, the quartz ingot prepared by the present application has better quality; compared with the method of preparing quartz ingot by using silicon tetrachloride as raw material, the preparation method of quartz ingot provided by the present application is more environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0010] Fig. 1 XRD pattern of the glassy high-purity quartz sand prepared in Example 1;

[0011] Fig. 2 Microscope picture of the glassy high-purity quartz sand prepared in Example 1;

[0012] Fig. 3 XRD pattern of the high-purity cristobalite prepared in Example 5. DETAILED DESCRIPTION

[0013] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is further described below in combination with specific embodiments and drawings.

[0014] The present application provides a preparation method of high-purity quartz ingot, which uses artificially synthesized high-purity quartz sand as raw material. The quartz ingot can be prepared from artificially synthesized high-purity quartz sand by plasma piling, melting and casting, etc.

[0015] Further, the artificially synthesized high-purity quartz sand includes two forms of amorphous and crystalline. Preferably, the artificially synthesized high-purity quartz sand includes glassy high-purity quartz sand, high-purity cristobalite, etc. The glassy quartz sand belongs to amorphous quartz sand, and the cristobalite belongs to crystalline quartz sand.

[0016] Further, the artificially synthesized high-purity quartz sand has a particle size greater than 1 μm.

[0017] Further, the artificially synthesized high-purity quartz sand has a purity greater than 99.9998%. The present application uses artificially synthesized high-purity quartz sand as raw material for preparing the quartz ingot, which solves the problem of high impurity element content in the quartz ingot from the root.

[0018] Further, the total content of K, Na, Li, Ca, Mg, Fe, Al, Cr, Cu, Mn, Ba, Ti, etc. in the artificially synthesized high-purity quartz sand is less than 2 ppm, and the content of a single impurity element is less than 1 ppm.

[0019] The present application provides a high-purity quartz ingot prepared by the aforementioned preparation method of high-purity quartz ingot.

[0020] Further, the total content of K, Na, Li, Ca, Mg, Fe, Al, Cr, Cu, Mn, Ba, Ti, etc. in the high-purity quartz ingot is less than 2 ppm, and the content of a single impurity element is less than 1 ppm.

[0021] Further, the high-purity quartz lump has a transmittance of greater than 80% at a deep ultraviolet wavelength of 165 nm. The quartz lump prepared by the method has good light transmittance at a deep ultraviolet wavelength, and can be used in the field of photolithography and other fields requiring high transmittance at a deep ultraviolet wavelength.

[0022] Further, the high-purity quartz lump has a hydroxyl content of less than 30 ppm. The lower the hydroxyl content, the better the temperature resistance of the quartz lump.

[0023] Further, the high-purity quartz lump is free of bubbles and air lines. The presence of bubbles and air lines can cause defects in subsequent products.

[0024] The application provides application of the high-purity quartz lump in production of quartz tubes, quartz rods and quartz plates.

[0025] The application further provides a method for preparing glassy high-purity quartz sand, comprising the following steps:

[0026] S1, preparing a slurry by adding water to nanoscale amorphous silicon dioxide, and performing spray drying on the slurry to obtain nanoscale silicon dioxide agglomerates;

[0027] S2, performing mechanical static pressing on the nanoscale silicon dioxide agglomerates prepared in step S1 to obtain blocky silicon dioxide;

[0028] S3, crushing, calcining and cooling the blocky silicon dioxide prepared in step S2 to obtain glassy high-purity quartz sand.

[0029] Further, the nanoscale amorphous silicon dioxide has an average particle size of 5-100 nm. Amorphous silicon dioxide is a non-crystalline silicon dioxide, and the application uses nanoscale amorphous silicon dioxide as a raw material to prepare glassy high-purity quartz sand. High-purity quartz sand in nature is crystalline, while the high-purity quartz sand prepared by the application is glassy, which belongs to a kind of amorphous and has a relatively low processing temperature.

[0030] Further, the slurry has a solid content of 5-50%. In the application, if the solid content is lower than the range, the powder obtained by spray drying has more fine particles and poor fluidity; if the solid content is higher than the range, the viscosity of the slurry is large and the nozzle is easily blocked.

[0031] Further, the spray drying has an inlet air temperature of 280-350 DEG C and an outlet air temperature of 80-120 DEG C. In the application, the nanoscale amorphous silicon dioxide is converted into nanoscale silicon dioxide agglomerates by spray drying.

[0032] Further, the average particle size of the nano-silica agglomerate is 100-500 μm. If the particle size is too large, the uniformity is poor; if the particle size is too small, it is not easy to prepare. Of course, the particle size of the nano-silica agglomerate is also affected by the particle size of the raw material nano-sized amorphous silica.

[0033] Further, the pressure of the mechanical static pressure is 150-250 MPa, and the time is 10-40 min. Since the nano-silica powder is very fluffy, if the powder is directly pressed, it will expand again and become loose when the pressure is removed, so it is necessary to first add water to prepare a slurry, and then spray dry to form large particles. In the present application, the mechanical static pressure is used to overcome the repulsive force between the nano-silica particles, so that the distance between the nano-silica particles is closer, thereby obtaining a product with fewer pores after sintering.

[0034] Further, the average particle size of the mechanically broken bulk silica is 50-400 μm.

[0035] Further, the calcination temperature is 1000-1600 °C, and the time is 3-8 h. By calcining the broken bulk silica, it is densified. If the calcination temperature is too high or the calcination time is too long, crystallization will occur, and the energy consumption will be high; if the calcination temperature is too low or the calcination time is too short, it cannot be completely melted, and the product obtained has a porous structure. Preferably, the calcination temperature is 1100-1200 °C, and the time is 5-6 h.

[0036] Example 1

[0037] Amorphous silica with a D50 particle size of 10 nm was added to water to prepare a slurry with a solid content of 20%; the slurry was spray dried (the inlet air temperature was 280 °C, and the outlet air temperature was 80 °C) to obtain a nano-silica agglomerate with a D50 particle size of 150 μm; the nano-silica agglomerate was subjected to mechanical static pressure (the pressure was 200 MPa, and the time was 0.5 h) to obtain bulk silica; the bulk silica was mechanically broken into particles with a D50 particle size of 70 μm, and was calcined at 1100 °C for 6 h and naturally cooled to obtain glassy high-purity quartz sand with a D50 particle size of 30 μm.

[0038] The glassy high-purity quartz sand was melted at 2000 °C to obtain high-purity quartz.

[0039] Example 2

[0040] Amorphous silica with a D50 particle size of 25 nm was added to water to prepare a slurry with a solid content of 5%; the slurry was spray dried (inlet air temperature of 350°C and outlet air temperature of 120°C) to obtain nano-silica agglomerates with a D50 particle size of 300 μm; the nano-silica agglomerates were subjected to mechanical static pressure (pressure of 250 MPa and time of 0.5 h) to obtain bulk silica; the bulk silica was mechanically broken into particles with a D50 particle size of 80 μm, calcined at 1200°C for 5 h, and naturally cooled to obtain glassy high-purity quartz sand with a D50 particle size of 45 μm.

[0041] The glassy high-purity quartz sand was melted at 2000°C to obtain high-purity quartz lumps.

[0042] Example 3

[0043] Amorphous silica with a D50 particle size of 90 nm was added to water to prepare a slurry with a solid content of 15%; the slurry was spray dried (inlet air temperature of 280°C and outlet air temperature of 80°C) to obtain nano-silica agglomerates with a D50 particle size of 500 μm; the nano-silica agglomerates were subjected to mechanical static pressure (pressure of 150 MPa and time of 0.5 h) to obtain bulk silica; the bulk silica was mechanically broken into particles with a D50 particle size of 90 μm, calcined at 1200°C for 6 h, and naturally cooled to obtain glassy high-purity quartz sand with a D50 particle size of 50 μm.

[0044] The glassy high-purity quartz sand was melted at 2000°C to obtain high-purity quartz lumps.

[0045] Example 4

[0046] Amorphous silica with a D50 particle size of 65 nm was added to water to prepare a slurry with a solid content of 50%; the slurry was spray dried (inlet air temperature of 280°C and outlet air temperature of 80°C) to obtain nano-silica agglomerates with a D50 particle size of 200 μm; the nano-silica agglomerates were subjected to mechanical static pressure (pressure of 200 MPa and time of 0.5 h) to obtain bulk silica; the bulk silica was mechanically broken into particles with a D50 particle size of 70 μm, calcined at 1100°C for 6 h, and naturally cooled to obtain glassy high-purity quartz sand with a D50 particle size of 50 μm.

[0047] The glassy high-purity quartz sand was melted at 2000°C to obtain high-purity quartz lumps.

[0048] Example 5

[0049] 3 kg of amorphous silica with a D50 particle size of 8 nm and a specific surface area of 150 m 2amorphous silica with a D50 particle size of 10 nm was mechanically hydrostatically pressed (pressure of 200 MPa and time of 0.5 h) to obtain blocky silica; after pressure release, the blocky silica cracked, and the blocky silica was mechanically broken into particles with a D50 particle size of 70 μm, which was calcined at 1100 °C for 6 h and naturally cooled to obtain opaque high-purity quartz sand with a D50 particle size of 30 μm. 10 CH3 was mixed with 100 g of ethanol to obtain a modification liquid, and the modification liquid was mixed with the dried amorphous silica to obtain a mixture, which was dried at 100 °C for 2 h and calcined at 1170 °C for 10 h to obtain high-purity cristobalite with a D50 particle size of 176 μm.

[0050] The high-purity cristobalite was melted at 2000 °C to obtain high-purity quartz ingot.

[0051] Comparative Example 1

[0052] High-purity quartz sand with a D50 particle size of 10 μm was used as the raw material for preparing the quartz ingot.

[0053] The high-purity quartz sand was melted at 2000 °C to obtain high-purity quartz ingot.

[0054] Comparative Example 2

[0055] The preparation method of the quartz sand was the same as in Example 1, except that the spray drying was not performed.

[0056] Amorphous silica with a D50 particle size of 10 nm was mechanically hydrostatically pressed (pressure of 200 MPa and time of 0.5 h) to obtain blocky silica; after pressure release, the blocky silica cracked, and the blocky silica was mechanically broken into particles with a D50 particle size of 70 μm, which was calcined at 1100 °C for 6 h and naturally cooled to obtain opaque high-purity quartz sand with a D50 particle size of 30 μm.

[0057] The opaque high-purity quartz sand was melted at 2000 °C to obtain high-purity quartz ingot.

[0058] Comparative Example 3

[0059] The preparation method of the quartz sand was the same as in Example 1, except that the mechanical hydrostatic pressing was not performed.

[0060] Amorphous silica with a D50 particle size of 10 nm was added to water to prepare a slurry with a solid content of 20%; the slurry was spray dried (inlet air temperature of 280 °C and outlet air temperature of 80 °C) to obtain nano-silica agglomerates with a D50 particle size of 150 μm; the nano-silica agglomerates were calcined at 1100 °C for 6 h and naturally cooled to obtain opaque high-purity quartz sand with a D50 particle size of 78 μm.

[0061] The opaque high-purity quartz sand was melted at 2000 °C to obtain high-purity quartz ingot.

[0062] Comparative Example 4

[0063] The preparation method of the quartz sand is the same as that in Example 3, except that the mechanical static pressure is not performed.

[0064] The amorphous silicon dioxide with a D50 particle size of 90 nm is subjected to mechanical static pressure (pressure of 150 MPa and time of 0.5 h) to obtain bulk silicon dioxide; after pressure release, the bulk silicon dioxide is cracked, and the bulk silicon dioxide is mechanically broken into particles with a D50 particle size of 90 μm, and is calcined at 1200 ℃ for 6 h and naturally cooled to obtain opaque high-purity quartz sand with a D50 particle size of 50 μm.

[0065] The opaque high-purity quartz sand is melted at 2000 ℃ to obtain high-purity quartz lumps.

[0066] Comparative Example 5

[0067] The preparation method of the quartz sand is the same as that in Example 3, except that the mechanical static pressure is not performed.

[0068] The amorphous silicon dioxide with a D50 particle size of 90 nm is added into water to prepare a slurry with a solid content of 15%; the slurry is subjected to spray drying (inlet air temperature of 280 ℃ and outlet air temperature of 80 ℃) to obtain nano-silicon dioxide agglomerates with a D50 particle size of 500 μm; the nano-silicon dioxide is calcined at 1200 ℃ for 6 h and naturally cooled to obtain opaque high-purity quartz sand with a D50 particle size of 380 μm.

[0069] The opaque high-purity quartz sand is melted at 2000 ℃ to obtain high-purity quartz lumps.

[0070] From Figs. 1-3 It can be seen that the glassy quartz sand is prepared in Example 1, the cristobalite is prepared in Example 5, and the opaque quartz sand is prepared in Comparative Examples 2-5.

[0071] The quartz sand and cristobalite prepared in Examples 1-5 and Comparative Examples 2-5 and the high-purity quartz sand in Comparative Example 1 are subjected to ICP-OES (inductively coupled plasma emission spectrometer) detection of impurity ions, and the detection limit is 1 ppb, and the results are shown in Table 1.

[0072] Table 1: Test results of impurity ions of quartz sand and cristobalite (unit: ppm)

[0073]

[0074]

[0075] It can be seen from Table 1 that, compared with the commercially available natural high-purity quartz sand, the glassy quartz sand and the cristobalite prepared in Examples 1-5 have higher purity, and the total content of impurity elements is less than 2 ppm.

[0076] The quartz ladle samples prepared in the above examples and comparative examples were detected for impurity ions by ICP-OES (inductively coupled plasma emission spectrometer) with a detection limit of 1 ppb, and the results are shown in Table 2.

[0077] Table 2 Test results of impurity ions of quartz ladle samples (unit: ppm)

[0078]

[0079]

[0080] As can be seen from Table 2, compared with commercially available high-purity quartz sand, the total content of impurity elements of the quartz ladle prepared by using artificially synthesized glassy high-purity quartz sand and high-purity cristobalite as raw materials is lower (less than 2 ppm), that is, the purity of the quartz ladle is higher.

[0081] The quartz ladle samples prepared in the above examples and comparative examples were tested for transmission ratio, hydroxyl content and bubble trace according to JC / T185-2013, GB / T12442-2019 and JC / T2392-2017, and the results are shown in Table 3.

[0082] Table 3 Test results of transmission ratio, hydroxyl content and bubble trace of quartz ladle samples

[0083]

[0084] As can be seen from Table 3, compared with commercially available high-purity quartz sand, the quartz ladle prepared by using artificially synthesized glassy high-purity quartz sand and high-purity cristobalite as raw materials has high ultraviolet light transmission ratio, low hydroxyl content and few bubble defects, and the main reason is that the artificially synthesized high-purity quartz sand has high purity and does not contain gas-liquid inclusions. The high-purity quartz sand obtained in Comparative Examples 2-5 is porous and opaque, and after being melted into a quartz ladle, it is still porous and cannot be tested for bubble number, and the ultraviolet light transmission ratio is small.

[0085] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method of producing high purity quartz ingot, characterized by: The artificial high-purity quartz sand is used as raw material, and the artificial high-purity quartz sand includes glassy high-purity quartz sand and high-purity cristobalite. The preparation method of the glassy high-purity quartz sand comprises the following steps: S1, nano-sized amorphous silicon dioxide is added into water to prepare a slurry, and the slurry is spray-dried to obtain nano-sized silicon dioxide agglomerates; S2, the nano-sized silicon dioxide agglomerates prepared in step S1 are subjected to mechanical static pressure to obtain blocky silicon dioxide; S3, the blocky silicon dioxide prepared in step S2 is crushed, calcined and cooled to obtain the glassy high-purity quartz sand.

2. The method of claim 1, wherein: The particle size of the artificial high-purity quartz sand is greater than 1 μm.

3. The method of claim 1, wherein: The purity of the artificial high-purity quartz sand is greater than 99.9998%.

4. The method of claim 1, wherein: The total content of impurity elements in the artificial high-purity quartz sand is less than 2 ppm, and the content of a single impurity element is less than 1 ppm.

5. The high-purity quartz lump prepared by the preparation method of any one of claims 1-4.

6. The high purity quartz gob of claim 5, wherein: The total content of impurity elements in the high-purity quartz lump is less than 2 ppm, and the content of a single impurity element is less than 1 ppm.

7. The high purity quartz gob of claim 5, wherein: The transmittance of the high-purity quartz lump at a 165 nm deep ultraviolet wave band is greater than 80%.

8. The high purity quartz gob of claim 5, wherein: The hydroxyl content of the high-purity quartz lump is less than 30 ppm.

9. The high purity quartz gob of claim 5, wherein: The high-purity quartz lump is free of bubbles and air lines.

10. The high-purity quartz lump of any one of claims 5-9 is applied in the production of quartz tubes, quartz rods and quartz plates.

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