WO2011083699A1 - 合成非晶質シリカ粉末及びその製造方法 - Google Patents
合成非晶質シリカ粉末及びその製造方法 Download PDFInfo
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- WO2011083699A1 WO2011083699A1 PCT/JP2010/073291 JP2010073291W WO2011083699A1 WO 2011083699 A1 WO2011083699 A1 WO 2011083699A1 JP 2010073291 W JP2010073291 W JP 2010073291W WO 2011083699 A1 WO2011083699 A1 WO 2011083699A1
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- silica powder
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- synthetic amorphous
- siliceous gel
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims abstract description 760
- 239000000843 powder Substances 0.000 title claims abstract description 652
- 229910002029 synthetic silica gel Inorganic materials 0.000 title claims abstract description 122
- 238000004519 manufacturing process Methods 0.000 title claims description 28
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 257
- 239000002245 particle Substances 0.000 claims abstract description 224
- 238000001035 drying Methods 0.000 claims abstract description 84
- 238000011282 treatment Methods 0.000 claims abstract description 52
- 229910021485 fumed silica Inorganic materials 0.000 claims description 56
- 238000010304 firing Methods 0.000 claims description 44
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 35
- 229910052799 carbon Inorganic materials 0.000 claims description 34
- 235000012239 silicon dioxide Nutrition 0.000 claims description 34
- 238000005406 washing Methods 0.000 claims description 34
- 239000000460 chlorine Substances 0.000 claims description 33
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 31
- 229910052801 chlorine Inorganic materials 0.000 claims description 31
- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical compound C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 claims description 30
- 238000000034 method Methods 0.000 claims description 30
- 239000005049 silicon tetrachloride Substances 0.000 claims description 30
- 238000005563 spheronization Methods 0.000 claims description 29
- 150000003377 silicon compounds Chemical class 0.000 claims description 17
- 238000010298 pulverizing process Methods 0.000 claims description 16
- 238000005469 granulation Methods 0.000 claims description 12
- 230000003179 granulation Effects 0.000 claims description 12
- 238000009835 boiling Methods 0.000 claims description 6
- 239000010419 fine particle Substances 0.000 claims 2
- 238000004140 cleaning Methods 0.000 abstract description 25
- 239000000499 gel Substances 0.000 description 89
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 84
- 238000003756 stirring Methods 0.000 description 81
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 80
- 229910021642 ultra pure water Inorganic materials 0.000 description 79
- 239000012498 ultrapure water Substances 0.000 description 79
- 239000007789 gas Substances 0.000 description 78
- 239000002994 raw material Substances 0.000 description 51
- VVTSZOCINPYFDP-UHFFFAOYSA-N [O].[Ar] Chemical compound [O].[Ar] VVTSZOCINPYFDP-UHFFFAOYSA-N 0.000 description 43
- 229910052757 nitrogen Inorganic materials 0.000 description 42
- 229910052786 argon Inorganic materials 0.000 description 40
- 238000004506 ultrasonic cleaning Methods 0.000 description 40
- 230000000052 comparative effect Effects 0.000 description 32
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 24
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 24
- 239000001301 oxygen Substances 0.000 description 24
- 229910052760 oxygen Inorganic materials 0.000 description 24
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 24
- 239000010453 quartz Substances 0.000 description 23
- 238000011084 recovery Methods 0.000 description 20
- 239000012298 atmosphere Substances 0.000 description 19
- 239000012299 nitrogen atmosphere Substances 0.000 description 19
- 239000000203 mixture Substances 0.000 description 13
- 230000000694 effects Effects 0.000 description 11
- 238000009826 distribution Methods 0.000 description 8
- 239000012535 impurity Substances 0.000 description 8
- 239000007788 liquid Substances 0.000 description 8
- 238000001179 sorption measurement Methods 0.000 description 8
- 239000013078 crystal Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 229910002026 crystalline silica Inorganic materials 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- 239000012300 argon atmosphere Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 239000011148 porous material Substances 0.000 description 4
- 239000004576 sand Substances 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 230000007062 hydrolysis Effects 0.000 description 3
- 238000006460 hydrolysis reaction Methods 0.000 description 3
- 230000003301 hydrolyzing effect Effects 0.000 description 3
- 230000006698 induction Effects 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000002105 nanoparticle Substances 0.000 description 2
- 238000001454 recorded image Methods 0.000 description 2
- -1 silicate ester Chemical class 0.000 description 2
- HNSDLXPSAYFUHK-UHFFFAOYSA-N 1,4-bis(2-ethylhexyl) sulfosuccinate Chemical compound CCCCC(CC)COC(=O)CC(S(O)(=O)=O)C(=O)OCC(CC)CCCC HNSDLXPSAYFUHK-UHFFFAOYSA-N 0.000 description 1
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 230000006399 behavior Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010835 comparative analysis Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000001739 density measurement Methods 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 238000009616 inductively coupled plasma Methods 0.000 description 1
- 238000004255 ion exchange chromatography Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000000634 powder X-ray diffraction Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000003980 solgel method Methods 0.000 description 1
- 239000004071 soot Substances 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J6/00—Heat treatments such as Calcining; Fusing ; Pyrolysis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
- C01B33/157—After-treatment of gels
- C01B33/158—Purification; Drying; Dehydrating
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/18—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/18—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
- C01B33/181—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof by a dry process
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B19/00—Other methods of shaping glass
- C03B19/10—Forming beads
- C03B19/1005—Forming solid beads
- C03B19/106—Forming solid beads by chemical vapour deposition; by liquid phase reaction
- C03B19/1065—Forming solid beads by chemical vapour deposition; by liquid phase reaction by liquid phase reactions, e.g. by means of a gel phase
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B19/00—Other methods of shaping glass
- C03B19/10—Forming beads
- C03B19/1095—Thermal after-treatment of beads, e.g. tempering, crystallisation, annealing
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C23/00—Other surface treatment of glass not in the form of fibres or filaments
- C03C23/0075—Cleaning of glass
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/06—Glass compositions containing silica with more than 90% silica by weight, e.g. quartz
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/30—Particle morphology extending in three dimensions
- C01P2004/32—Spheres
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/54—Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/12—Surface area
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/02—Pure silica glass, e.g. pure fused quartz
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
- Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
Definitions
- the present invention relates to a high-purity synthetic amorphous silica powder suitable as a raw material for producing synthetic silica glass products such as piping and crucibles used under high temperature and reduced pressure environments in the semiconductor industry and the like, and a method for producing the same.
- crucibles and jigs used for manufacturing single crystals for semiconductors have been manufactured using quartz powder obtained by pulverizing and refining natural quartz and silica sand as raw materials.
- natural quartz and silica sand contain various metal impurities, and even if the above purification treatment is performed, the metal impurities cannot be completely removed, so that the purity is not satisfactory.
- semiconductors are highly integrated, quality requirements for single crystals as materials have increased, and high-purity products are required for crucibles and jigs used in the production of single crystals. Therefore, synthetic silica glass products using high-purity synthetic amorphous silica powder as a raw material instead of natural quartz or silica sand have attracted attention.
- high-purity silicon tetrachloride is hydrolyzed with water, and the resulting silica gel is dried, sized and fired to obtain a synthetic amorphous silica powder.
- a method is disclosed (for example, refer to Patent Document 1). Also disclosed is a method for obtaining a synthetic amorphous silica powder by hydrolyzing an alkoxysilane such as a silicate ester in the presence of an acid and an alkali to form a gel, and drying, pulverizing and firing the resulting gel.
- the synthetic amorphous silica powder produced by the methods described in the above Patent Documents 1 to 3 has a higher purity than natural quartz and silica sand, and is used to synthesize crucibles and jigs produced from these raw materials. Impurity contamination from silica glass products can be reduced and performance can be improved.
- Japanese Patent Publication No. 4-75848 (Claim 1) Japanese Patent Laid-Open No. 62-176929 (claim 1) JP-A-3-275527 (page 2, lower left column, line 7 to page 3, upper left column, line 6)
- the synthetic silica glass product produced using the synthetic amorphous silica powder produced by the methods described in the above Patent Documents 1 to 3 is used in an environment where the synthetic silica glass product is used at high temperature and reduced pressure. In this case, bubbles were generated or expanded, and the performance of the synthetic silica glass product was greatly reduced.
- a crucible for pulling up a silicon single crystal is used in a high temperature and reduced pressure environment at around 1500 ° C. and around 7000 Pa, and the drastic reduction in the performance of the crucible due to the generation or expansion of the above-mentioned bubbles results in a single crystal to be pulled up. It has become a problem that affects the quality of.
- the synthetic amorphous silica powder obtained by hydrolysis of silicon tetrachloride is subjected to heat treatment,
- concentration of hydroxyl and carbon in the synthetic amorphous silica powder By reducing the concentration of hydroxyl and chlorine, respectively, and by subjecting the synthetic amorphous silica powder obtained by the sol-gel method of alkoxysilane to heat treatment It is conceivable to reduce the concentration of impurities that can be gas components in the synthetic amorphous silica powder.
- the object of the present invention is to overcome the above-mentioned conventional problems and to provide a synthetic amorphous material suitable for a raw material for a synthetic silica glass product with less generation or expansion of bubbles even when used under a high temperature and reduced pressure environment. It is to provide a porous silica powder and a production method thereof.
- the first aspect of the present invention is a synthetic amorphous silica powder having an average particle diameter D 50 of 10 to 2000 ⁇ m obtained by subjecting the granulated silica powder to spheroidization treatment, washing and drying.
- the value obtained by dividing the BET specific surface area by the theoretical specific surface area calculated from the average particle diameter D 50 is 1.00 to 1.35, the true density is 2.10 to 2.20 g / cm 3 , and the intra-particle space ratio is 0. -0.05, circularity is 0.75-1.00, and undissolved rate is 0.00-0.25.
- a second aspect of the present invention is an invention based on the first aspect, which is a synthetic amorphous silica powder obtained by sintering granulated silica powder and then spheroidizing treatment, and having a carbon concentration Is less than 2 ppm or the chlorine concentration is less than 2 ppm, or both.
- a third aspect of the present invention is an invention based on the second aspect, wherein the further granulated silica powder hydrolyzes silicon tetrachloride to produce a siliceous gel, and this siliceous gel Is a silica powder obtained by pulverizing and classifying the dried powder, characterized by having a carbon concentration of less than 2 ppm.
- a fourth aspect of the present invention is an invention based on the second aspect, wherein the further granulated silica powder hydrolyzes the organic silicon compound to produce a siliceous gel.
- the gel is dried to obtain a dry powder, and the dry powder is pulverized and then classified, and is characterized by a chlorine concentration of less than 2 ppm.
- a fifth aspect of the present invention is an invention based on the second aspect, wherein the further granulated silica powder generates fumed silica to form a siliceous gel, and the siliceous gel is dried.
- a silica powder obtained by pulverizing and classifying the dried powder, and having a carbon concentration of less than 2 ppm and a chlorine concentration of less than 2 ppm.
- a sixth aspect of the present invention is a granulating step of producing a siliceous gel, drying the siliceous gel to obtain a dry powder, pulverizing the dry powder, and then classifying the powder to obtain a silica powder.
- the silica powder obtained in the above granulation step is put into a plasma torch that has generated plasma at a predetermined high-frequency output at a predetermined supply rate, and is heated and melted at a temperature from 2000 ° C. to the boiling point of silicon dioxide.
- a method for producing a synthetic amorphous silica powder characterized by obtaining a synthetic amorphous silica powder of 0.25.
- a seventh aspect of the present invention is the invention based on the sixth aspect, wherein the granulation step further hydrolyzes silicon tetrachloride to produce a siliceous gel, and the siliceous gel is dried.
- the dry powder is pulverized and then classified to obtain a silica powder having an average particle diameter D 50 of 10 to 3000 ⁇ m.
- the eighth aspect of the present invention is the invention based on the sixth aspect, wherein the granulating step further hydrolyzes the organic silicon compound to produce a siliceous gel, and the siliceous gel is dried.
- the dry powder is pulverized and classified to obtain a silica powder having an average particle diameter D 50 of 10 to 3000 ⁇ m.
- a ninth aspect of the present invention is the invention based on the sixth aspect, wherein the granulation step further produces a siliceous gel using fumed silica, and the siliceous gel is dried and dried.
- This is characterized in that it is a step of obtaining a silica powder having an average particle diameter D 50 of 10 to 3000 ⁇ m by pulverizing and classifying the dried powder.
- a tenth aspect of the present invention is a granulating step of producing a siliceous gel, drying the siliceous gel to form a dry powder, pulverizing the dry powder, and then classifying the powder to obtain a silica powder.
- the silica powder obtained in the granulation step is calcined at a temperature of 800 to 1450 ° C., and the calcining step at a predetermined supply rate in a plasma torch that generates plasma at a predetermined high frequency output.
- the silica powder is charged, heated at a temperature from 2000 ° C.
- a washing step and a drying step for drying the silica powder after the washing step are included in this order.
- a high frequency output (W) in the spheroidizing step is A, and a silica powder supply rate (kg / hr) is B.
- the high frequency output A is greater than or conditions 90kW, and performed by adjusting so that the value of A / B (W ⁇ hr / kg) is 1.0 ⁇ 10 4 or more, an average particle diameter D 50 Is 10 to 2000 ⁇ m, BET specific surface area divided by theoretical specific surface area calculated from average particle diameter D 50 is 1.00 to 1.35, true density is 2.10 to 2.20 g / cm 3 , intraparticle space
- the rate is 0 to 0.05, the circularity is 0.75 to 1.00, the undissolved rate is 0.00 to 0.25, and the carbon concentration is less than 2 ppm or the chlorine concentration is less than 2 ppm, or A method for producing a synthetic amorphous silica powder characterized by satisfying both.
- An eleventh aspect of the present invention is the invention based on the tenth aspect, wherein the granulating step further hydrolyzes silicon tetrachloride to produce a siliceous gel, and the siliceous gel is dried.
- the carbon concentration of the resulting synthetic amorphous silica powder is less than 2 ppm. It is characterized by being.
- a twelfth aspect of the present invention is the invention based on the tenth aspect, wherein the granulating step further hydrolyzes the organic silicon compound to produce a siliceous gel, and the siliceous gel is dried.
- the resulting amorphous amorphous silica powder has a chlorine concentration of 2 ppm. It is characterized by being less than.
- a thirteenth aspect of the present invention is the invention based on the tenth aspect, wherein the granulating step further generates a siliceous gel using fumed silica, and the siliceous gel is dried and dried.
- the resulting amorphous carbon powder has a carbon concentration of less than 2 ppm, chlorine The concentration is less than 2 ppm.
- the synthetic amorphous silica powder according to the first aspect of the present invention is a synthetic amorphous powder having an average particle diameter D 50 of 10 to 2000 ⁇ m obtained by subjecting the granulated silica powder to spheroidization, washing and drying.
- Amorphous silica powder the value obtained by dividing the BET specific surface area by the theoretical specific surface area calculated from the average particle diameter D 50 is 1.00 to 1.35, and the true density is 2.10 to 2.20 g / cm 3.
- the intra-particle space ratio is 0 to 0.05, the circularity is 0.75 to 1.00, and the undissolved ratio is 0.00 to 0.25.
- the synthetic amorphous silica powder according to the second aspect of the present invention is a synthetic amorphous silica powder obtained by baking the granulated silica powder and then spheroidizing, and the carbon concentration is less than 2 ppm or Satisfy one or both of chlorine concentrations less than 2 ppm. For this reason, if a synthetic silica glass product is produced using this synthetic amorphous silica powder, the amount of gas components adsorbed on the surface of the raw material powder is reduced, and the gas component inside the powder is reduced, so that bubbles are generated. Or expansion can be reduced.
- the gas component adsorbed on the surface and the gas component inside the powder are extremely small by firing before spheroidizing treatment, and bubbles are generated in the synthetic silica glass product. Or the effect of reducing expansion is further enhanced.
- the granulated silica powder forms a siliceous gel using fumed silica, and the siliceous gel is dried to obtain a dry powder.
- the silica powder obtained by pulverizing and classifying the dried powder achieves a carbon concentration of less than 2 ppm and a chlorine concentration of less than 2 ppm.
- fumed silica is used as silica powder as a raw material powder, which is obtained by reacting a chlorine-based silicon compound in a liquid or an organic silicon compound such as tetramethoxysilane. Since the carbon concentration and the chlorine concentration are further suppressed as compared with those obtained by using the obtained powder as the raw material powder, the effect of reducing the generation or expansion of bubbles in the synthetic silica glass product is further enhanced.
- the synthetic amorphous silica powder production method includes, for example, hydrolyzing silicon tetrachloride to form a siliceous gel or using an organic silicon compound such as tetramethoxysilane. Hydrolysis produces a siliceous gel or fumed silica is used to produce a siliceous gel. Then, the siliceous gel is dried to obtain a dry powder, and after the dry powder is pulverized, it is classified to obtain a silica powder having a desired average particle diameter, and plasma is generated at a predetermined high-frequency output.
- the silica powder obtained in the granulation step is charged into the plasma torch at a predetermined supply rate, heated at a temperature from 2000 ° C. to the boiling point of silicon dioxide, and melted, and the spheronization step by thermal plasma is performed.
- a high-frequency output (W) in the spheronization step includes, in this order, a washing step for removing fine powder adhering to the surface of the spheroidized silica powder after the spheronization step and a drying step for drying the silica powder after the washing step.
- Is A and the supply rate of silica powder (kg / hr) is B
- the high frequency output A is 90 kW or more
- the value of A / B (W ⁇ hr / kg) is 1.0 ⁇ 10 4.
- the average particle diameter D 50 is 10 to 2000 ⁇ m
- the BET specific surface area divided by the theoretical specific surface area calculated from the average particle diameter D 50 is 1.00 to 1.35
- the true density is 2.10-2.20 g / cm 3
- Synthetic amorphous with intraparticle space ratio of 0-0.05, circularity of 0.75-1.00 and undissolved ratio of 0.00-0.25 Silica powder is obtained.
- a synthetic amorphous silica powder that can be suitably used as a raw material for synthetic silica glass products can be easily obtained because of the small amount of inevitable gas adsorption and the small amount of gas components inside the powder. Can be manufactured.
- the method for producing a synthetic amorphous silica powder according to the tenth to thirteenth aspects of the present invention includes, for example, hydrolyzing silicon tetrachloride to form a siliceous gel, or using an organic silicon compound such as tetramethoxysilane. Hydrolysis produces a siliceous gel or fumed silica is used to produce a siliceous gel. Then, the siliceous gel was dried to obtain a dry powder, and the dry powder was pulverized and then classified to obtain a silica powder having a desired average particle diameter, and the above granulation step was performed.
- the silica powder obtained in the above baking process is charged at a predetermined supply rate into a plasma torch in which the silica powder is fired at a temperature of 800 to 1450 ° C. and plasma is generated at a predetermined high frequency output.
- Spheroidizing step by thermal plasma heated and melted at a temperature from the boiling point of silicon dioxide, a cleaning step of removing fine powder adhering to the spheroidized silica powder surface after the spheronizing step, and after the cleaning step
- a synthetic amorphous silica powder that can be suitably used as a raw material for synthetic silica glass products can be easily obtained because of the small amount of inevitable gas adsorption and the small amount of gas components inside the powder.
- this manufacturing method by providing a firing step under a predetermined condition before the spheroidizing treatment step, the gas component adsorbed on the surface and the gas component inside the powder can be extremely reduced.
- a synthetic amorphous silica powder having a higher effect of reducing the generation or expansion of bubbles in the product can be produced.
- the synthetic amorphous silica powder of the first embodiment of the present invention can be obtained by subjecting the granulated silica powder to spheroidization, washing and drying.
- the value obtained by dividing the BET specific surface area by the theoretical specific surface area calculated from the average particle diameter D 50 is 1.00 to 1.35, the true density is 2.10 to 2.20 g / cm 3 , and the intra-particle space ratio is 0. -0.05, circularity is 0.75-1.00, and undissolved rate is 0.00-0.25.
- the synthetic amorphous silica powder of the second embodiment of the present invention is a synthetic amorphous silica powder obtained by baking the granulated silica powder and then spheroidizing it.
- the carbon concentration is less than 2 ppm or the chlorine concentration is less than 2 ppm, or both.
- the main cause of the generation or expansion of bubbles in a synthetic silica glass product such as a silicon single crystal pulling crucible at high temperature and under reduced pressure is considered to be the gas adsorbed on the surface of the raw material powder used in the production of the product. That is, when the synthetic silica glass product is manufactured, the gas component adsorbed on the surface of the raw material powder is released during melting, which is one step. And this gas component remains in a synthetic silica glass product, and this causes a bubble generation or expansion.
- the silica powder used as the raw material for the synthetic silica glass product usually undergoes a pulverization step, it contains a large number of irregularly shaped (pulverized powder shape) particles as shown in FIG. Therefore, it is considered that the specific surface area increases and the inevitable gas adsorption amount increases.
- synthetic amorphous silica powder of the present invention by performing the spheroidizing treatment to the powder, the value obtained by dividing the theoretical specific surface area, as calculated BET specific surface area average particle diameter D 50 is obtained by the above-mentioned range .
- the BET specific surface area is a value measured by the BET three-point method.
- the theoretical specific surface area of the particle is calculated from the following equation (1) when it is assumed that the particle is a true sphere and the surface is smooth.
- D represents the particle diameter
- ⁇ represents the true density.
- Theoretical specific surface area 6 / (D ⁇ ⁇ ) (1)
- the theoretical specific surface area of the powder is a value calculated from the theoretical true density assuming that D is the average particle diameter D 50 of powder and ⁇ is the true density of 2.20 g / cm 3 in the above formula (1). It is. That is, the theoretical specific surface area of the powder is calculated from the following equation (2).
- Theoretical specific surface area of the powder 2.73 / D 50 (2)
- the specific surface area is increased, the gas adsorption amount of unavoidable increases.
- the above value is preferably in the range of 1.00 to 1.15. When the above value is larger than 1.15, the generation of bubbles or the effect of reducing expansion is small.
- the average particle diameter D 50 of the small side due to the presence of the peak deviation and particle size distribution of the particle size distribution, if the measurement of the average particle diameter D 50 decreases, the theoretical specific surface area, as calculated BET specific surface area average particle diameter
- the value divided by may be less than 1.00. In that case, a value obtained by dividing the BET specific surface area by the theoretical specific surface area calculated from the average particle diameter is defined as 1.00.
- the circularity of the synthetic amorphous silica powder is 0.75 or more.
- the circularity means that the closer to 1.00, the closer the powder particle is to a true sphere, and it is calculated by the following equation (3).
- Circularity 4 ⁇ S / L 2 (3)
- S represents the area of the photographed particle projection
- L represents the perimeter of the particle projection.
- the circularity of the powder is an average value of 200 powder particles calculated from the above formula (3).
- the circularity of the powder is less than 0.75, the effect of reducing the generation or expansion of bubbles is small.
- the circularity of the powder is preferably in the range of 0.80 to 1.00.
- the undissolved rate of the synthetic amorphous silica powder is 0.25 or less.
- the undissolved ratio of the powder indicates the ratio of the powder particles that are square in the above-described particle projection diagram of 200 powder particles.
- the undissolved rate is larger than 0.25, the effect of reducing the generation or expansion of bubbles is small.
- the undissolved rate of the powder is preferably in the range of 0.00 to 0.10.
- the true density is at 2.10 g / cm 3 or more, and preferably 2.15 ⁇ 2.20g / cm 3.
- the true density is an average value obtained by measuring the true density three times in accordance with the measurement method (d) true specific gravity measurement of JIS R7212 carbon block.
- grain space ratio is 0.05 or less, and 0.01 or less is preferable.
- the intra-particle space ratio is a measurement of the cross-sectional area of a particle when the cross-section of the 50 powder particles is observed with an SEM (scanning electron microscope), and the area of the space if there is a space in the particle. This is the average value of the values calculated from the equation (4).
- the average particle diameter D 50 of the synthetic amorphous silica powder is 10 to 2000 ⁇ m, and preferably in the range of 50 to 1000 ⁇ m. If it is less than the lower limit, the space between the powder particles is small, and it is difficult for the gas present in this space to escape, so small bubbles tend to remain, whereas if the upper limit is exceeded, the space between the powder particles is too large, This is because large bubbles are likely to remain.
- the average particle diameter D 50 is particularly preferably in the range of 80 to 600 ⁇ m.
- the average particle diameter D 50 is obtained by measuring the median of the particle distribution (diameter) measured by a laser diffraction / scattering particle distribution measuring apparatus (model name: HORIBA LA-950) three times. Mean value.
- the bulk density of the synthetic amorphous silica powder is preferably 1.00 g / cm 3 or more. If it is less than the lower limit, the space between the powder particles is too large and large bubbles are likely to remain. On the other hand, if the upper limit is exceeded, the space between the powder particles is small, so that the gas present in this space is difficult to escape. This is because small bubbles are likely to remain.
- the bulk density is particularly preferably in the range of 1.20 to 1.50 g / cm 3 .
- the crystalline silica powder has a broad diffraction peak and no crystalline silica powder is observed when measured by a powder X-ray diffraction method using CuK ⁇ rays.
- Amorphous and crystalline silica have different behaviors in melting, and the melting of crystalline silica tends to start later. For this reason, if a synthetic silica glass product or the like is manufactured using a synthetic amorphous silica powder in which amorphous and crystalline silica are mixed, bubbles are likely to remain in the synthetic silica glass product. It is.
- the impurity concentration of the synthetic amorphous silica powder is 1A group excluding hydrogen atoms, 2A-8 group, 1B-3B group, 4B excluding carbon and silicon.
- the concentration of group 5B, group 6B excluding oxygen, and group 7B excluding chlorine is preferably less than 1 ppm.
- the impurity concentration is particularly preferably less than 0.05 ppm.
- the hydroxyl group which can become a gas component is 60 ppm or less, the chlorine concentration is 5 ppm or less, and the carbon concentration is 5 ppm or less.
- the synthetic amorphous silica powder according to the second embodiment of the present invention by firing before the spheroidizing treatment, the gas component adsorbed on the surface and the gas component inside the powder are extremely reduced, and the synthetic silica The effect of reducing the generation or expansion of bubbles in the glass product is further enhanced. That is, by firing the granulated silica powder under predetermined conditions, it is possible to achieve one or both of a chlorine concentration of less than 2 ppm and a carbon concentration of less than 2 ppm.
- the siliceous gel is dried to obtain a dry powder, and this dry powder is pulverized.
- the carbon concentration is less than 2 ppm by firing under predetermined conditions before the spheroidization treatment. This is because the silica powder has a lower carbon concentration than the silica powder obtained using an organic silicon compound such as tetramethoxysilane, so that the synthetic amorphous silica powder obtained using this as the raw material powder Then, the residual carbon concentration is relatively reduced.
- the granulated silica powder hydrolyzes the organic silicon compound to produce a siliceous gel.
- the siliceous gel is dried to form a dry powder, and the dry powder is pulverized and then classified.
- a chlorine concentration will be less than 2 ppm by baking on predetermined conditions before a spheroidization process.
- the silica powder has a lower chlorine concentration than the silica powder obtained by reacting a chlorinated silicon compound in the liquid, and therefore remains in the synthetic amorphous silica powder obtained by using this as a raw material powder. Chlorine concentration is relatively reduced.
- the granulated silica powder is obtained by forming a siliceous gel using fumed silica, drying the siliceous gel to obtain a dry powder, pulverizing the dry powder, and then classifying it.
- the carbon concentration is less than 2 ppm and the chlorine concentration is less than 2 ppm by firing under predetermined conditions before the spheronization treatment.
- Synthetic amorphous silica powder obtained by using silica powder obtained by reacting raw material powder with a chlorine-based silicon compound in a liquid tends to have a relatively high residual chlorine concentration.
- the synthetic amorphous silica powder obtained by using an organic silicon compound as the raw material powder the residual carbon concentration tends to be relatively high.
- fumed silica since fumed silica has a lower chlorine concentration and carbon concentration than the above two silica powders, synthetic amorphous silica powder obtained by using fumed silica as a raw material powder has both chlorine concentration and carbon concentration. Is greatly reduced. Thereby, the effect of reducing the generation or expansion of bubbles in the synthetic silica glass product is further enhanced.
- the synthetic amorphous silica powder of the present invention contains many particles that are melted and spheronized as shown in FIG. 1 or FIG. 2 by washing and drying after spheroidizing treatment.
- the synthetic amorphous silica powder of the present invention contains many particles close to true spheres, the circularity and undissolution rate of the powder show the above ranges, and the inevitable gas adsorption amount is reduced.
- the melted and spheroidized particles may include a plurality of agglomerated particles, but the agglomerated ones constitute one particle, and the ratios such as the circularity and undissolved rate are specified. Yes.
- the method for producing a synthetic amorphous silica powder according to the first embodiment of the present invention is obtained by subjecting a silica powder as a raw material to a spheroidizing treatment, followed by washing and drying.
- the raw silica powder is fired, and the fired silica powder is spheroidized, Obtained by washing and drying.
- the silica powder used as the raw material for the synthetic amorphous silica powder of the present invention is obtained, for example, by the following method.
- a first method first, ultrapure water in an amount corresponding to 45 to 80 mol is prepared with respect to 1 mol of silicon tetrachloride.
- the prepared ultrapure water is put into a container, and hydrolyzed by adding silicon tetrachloride while stirring at a temperature of 20 to 45 ° C. in an atmosphere of nitrogen, argon or the like. After the addition of silicon tetrachloride, stirring is continued for 0.5 to 6 hours to produce a siliceous gel. At this time, the stirring speed is preferably in the range of 100 to 300 rpm.
- the above siliceous gel is transferred to a drying container and placed in a dryer, and at a temperature of 200 ° C. to 300 ° C. while flowing nitrogen, argon or the like at a flow rate of preferably 10 to 20 L / min. Dry for 12 to 48 hours to obtain a dry powder.
- the dry powder is taken out from the dryer and pulverized using a pulverizer such as a roll crusher. In the case of using a roll crusher, the roll gap is appropriately adjusted to 0.2 to 2.0 mm and a roll rotation speed of 3 to 200 rpm.
- the pulverized dry powder is classified using a vibration sieve or the like to obtain silica powder having an average particle diameter D 50 of 10 to 3000 ⁇ m, preferably 70 to 1300 ⁇ m.
- 0.5 to 3 mol of ultrapure water and 0.5 to 3 mol of ethanol are prepared with respect to 1 mol of tetramethoxysilane as an organic silicon compound.
- the prepared ultrapure water and ethanol are put in a container, and tetramethoxysilane is added and hydrolyzed in an atmosphere of nitrogen, argon or the like while maintaining the temperature at 60 ° C. and stirring.
- tetramethoxysilane After stirring for 5 to 120 minutes after adding tetramethoxysilane, 1 to 50 mol of ultrapure water is further added to 1 mol of tetramethoxysilane, and stirring is continued for 1 to 12 hours.
- the stirring speed is preferably in the range of 100 to 300 rpm.
- the above siliceous gel is transferred to a drying container and placed in a dryer, and at a temperature of 200 ° C. to 300 ° C. while flowing nitrogen, argon or the like at a flow rate of preferably 10 to 20 L / min. Dry for 6 to 48 hours to obtain a dry powder.
- the dry powder is taken out from the dryer and pulverized using a pulverizer such as a roll crusher. In the case of using a roll crusher, the roll gap is appropriately adjusted to 0.2 to 2.0 mm and a roll rotation speed of 3 to 200 rpm.
- the pulverized dry powder is classified using a vibration sieve or the like to obtain silica powder having an average particle diameter D 50 of 10 to 3000 ⁇ m, preferably 70 to 1300 ⁇ m.
- the prepared ultrapure water is put in a container, and fumed silica is added while stirring at a temperature of 10 to 30 ° C. in an atmosphere of nitrogen, argon or the like.
- stirring is continued for 0.5 to 6 hours to form a siliceous gel.
- the stirring speed is preferably in the range of 10 to 50 rpm.
- the siliceous gel is transferred to a drying container and placed in a drier.
- the temperature is set to 200 ° C. to 300 ° C. Dry for 12 to 48 hours to obtain a dry powder.
- the dry powder is taken out from the dryer and pulverized using a pulverizer such as a roll crusher. In the case of using a roll crusher, the roll gap is appropriately adjusted to 0.2 to 2.0 mm and a roll rotation speed of 3 to 200 rpm.
- the pulverized dry powder is classified using a vibration sieve or the like to obtain silica powder having an average particle diameter D 50 of 10 to 3000 ⁇ m, preferably 70 to 1300 ⁇ m.
- the silica powder thus granulated is subjected to a spheroidizing treatment under the conditions described later.
- the spheroidizing treatment is performed. Before, as shown in FIG. 4, baking is performed under predetermined conditions. This firing is performed in a heat-resistant glass or quartz container at a temperature of 800 to 1450 ° C. in an air or nitrogen atmosphere. By providing the baking step before the spheroidizing treatment step, the gas component adsorbed on the surface and the gas component inside the powder can be extremely reduced.
- the powder granulated from fumed silica has nano-sized closed pores, pores remain in the particles when the powder is subjected to a spheronization treatment. For this reason, the nano-sized closed pores can be eliminated by firing the powder granulated from the fumed silica before the spheroidization treatment. If the firing temperature is less than the lower limit, the effect of reducing impurities by firing and the effect of eliminating the closed pores in fumed silica cannot be obtained sufficiently. On the other hand, when the firing temperature exceeds the upper limit, a problem of sticking between the powders occurs.
- the spheroidization of the silica powder obtained by the above first to third methods or the silica powder obtained by firing the powder under the above conditions is performed by a spheroidization treatment using thermal plasma.
- a spheroidization treatment using thermal plasma for example, an apparatus shown in FIG. 5 can be used.
- the apparatus 30 includes a plasma torch 31 that generates plasma, a chamber 32 that is a reaction cylinder provided below the plasma torch 31, and a collection unit that collects the processed powder provided below the chamber 32. 33.
- the plasma torch 31 has a quartz tube 34 sealed at the top communicating with the chamber 32 and a high-frequency induction coil 36 around which the quartz tube 34 is wound.
- a raw material supply pipe 37 is provided through the quartz tube 34 and a gas introduction pipe 38 is connected thereto.
- a gas exhaust port 39 is provided on the side of the chamber 32.
- the plasma torch 31 when the high-frequency induction coil 36 is energized, plasma 40 is generated, and a gas such as argon or oxygen is supplied from the gas introduction tube 38 to the quartz tube 34.
- the raw material powder is supplied into the plasma 40 through the raw material supply pipe 37. Further, the gas in the chamber 32 is exhausted from a gas exhaust port 39 provided on the side of the chamber 32.
- argon as a working gas is introduced from the gas introduction pipe 38 of the apparatus 30 at a flow rate of 60 to 100 L / min, and the frequency is 2 to 3 MHz, the output is 90 kW or more, preferably the output is 120 to A high frequency of 1000 kW is applied to the plasma torch 31 to generate plasma.
- oxygen is gradually introduced at a flow rate of 30 to 125 L / min to generate an argon-oxygen plasma.
- the silica powder obtained by the above first to third methods is introduced into the argon-oxygen plasma from the raw material supply pipe 37 at a supply rate of 3.5 to 17.5 kg / hr to obtain the silica powder. By melting and dropping the melted particles, the recovered particles are recovered by the recovery unit 33, whereby the spheroidized silica powder 41 can be obtained.
- the working gas argon is first introduced from the gas introduction pipe 38 of the apparatus 30 at a flow rate of 50 to 80 L / min, and a high frequency of 2 to 3 MHz and an output of 90 to 120 kW is generated. It is applied to the plasma torch 31 to generate plasma. After the plasma is stabilized, oxygen is gradually introduced at a flow rate of 30 to 90 L / min to generate an argon-oxygen plasma. Next, the fired silica powder is charged into the argon-oxygen plasma from the raw material supply pipe 37 at a supply rate of 3.5 to 11.5 kg / hr, and the silica powder is melted to form melt particles. , And the fallen particles are collected by the collection unit 33, whereby the spheroidized silica powder 41 can be obtained.
- Adjustment of the circularity, the undissolved rate, etc. in the synthetic amorphous silica powder can be performed by adjusting the high frequency output, the silica powder supply rate, and the like.
- the high frequency output (W) is A and the supply rate (kg / hr) of silica powder is B
- the high frequency output A is 90 kW or more
- the desired circularity and undissolved rate can be obtained by adjusting the supply speed B so that the value of A / B (W ⁇ hr / kg) is in the range of 1.0 ⁇ 10 4 or more.
- the silica powder after spheroidization treatment has fine silica powder evaporated in argon-oxygen plasma on its surface, put the spheroidized silica powder and ultrapure water after the spheronization process into a cleaning container. Perform ultrasonic cleaning. After the ultrasonic cleaning, the silica powder is filtered through a coarse filter in order to move into the ultrapure water. This operation is repeated until there is no more fine silica powder.
- the silica powder after the washing step is dried by first putting the powder in a drying container and placing the drying container in a dryer. Then, it is preferably carried out by keeping the temperature of 100 ° C. to 400 ° C. for 3 to 48 hours while flowing nitrogen, argon or the like in the dryer at a flow rate of 1 to 20 L / min.
- the synthetic amorphous silica powder of the present invention is obtained.
- This synthetic amorphous silica powder has a small amount of inevitable gas adsorption and can be suitably used as a raw material for synthetic silica glass products.
- the gas components adsorbed on the surface and the gas components inside the powder can be extremely reduced. it can.
- Example 1 First, an amount of ultrapure water corresponding to 55.6 mol was prepared with respect to 1 mol of silicon tetrachloride. This ultrapure water was put in a container, and hydrolyzed by adding silicon tetrachloride while stirring at a temperature of 25 ° C. in a nitrogen atmosphere. Stirring was continued for 2 hours after the addition of silicon tetrachloride to produce a siliceous gel. At this time, the stirring speed was 100 rpm. Next, the siliceous gel was transferred to a drying container, put in a dryer, and dried at a temperature of 200 ° C. for 24 hours while flowing nitrogen at a flow rate of 10 L / min in the dryer to obtain a dry powder. .
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm, and the roll rotation speed was adjusted to 40 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 100 ⁇ m and an opening of 150 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 124 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the obtained silica powder without firing under the conditions shown in Table 1 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the washed powder is put into a drying container, this drying container is put into a dryer, and kept at a temperature of 200 ° C. for 48 hours while flowing at a flow rate of nitrogen of 10 L / min in the dryer.
- Amorphous silica powder was obtained.
- Example 2 2 mol of ultrapure water and 2 mol of ethanol are prepared for 1 mol of tetramethoxysilane.
- the prepared ultrapure water and ethanol were put in a container, and tetramethoxysilane was added and hydrolyzed while stirring at a temperature of 60 ° C. in a nitrogen atmosphere.
- 30 mol of ultrapure water was further added to 1 mol of tetramethoxylane, and stirring was continued for 5 hours to produce a siliceous gel. At this time, the stirring speed was 100 rpm.
- the siliceous gel was transferred to a drying container, put in a dryer, and dried at a temperature of 200 ° C. for 48 hours while flowing nitrogen at a flow rate of 20 L / min into the dryer to obtain a dry powder. .
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm, and the roll rotation speed was adjusted to 55 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 100 ⁇ m and an opening of 150 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 135 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the obtained silica powder without firing under the conditions shown in Table 1 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- Example 3 10 mol of ultrapure water is prepared for 1 mol of fumed silica having an average particle diameter D 50 of 0.030 ⁇ m and a specific surface area of 50 m 2 / g.
- the prepared ultrapure water was put in a container, and fumed silica was added while stirring at a temperature of 25 ° C. in a nitrogen atmosphere. After the fumed silica was added, stirring was continued for 3 hours to produce a siliceous gel. At this time, the stirring speed was 30 rpm. Next, the siliceous gel was transferred to a drying container, put in a dryer, and dried at a temperature of 300 ° C.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.5 mm, and the roll rotation speed was adjusted to 100 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 400 ⁇ m and an opening of 500 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 459 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the obtained silica powder without firing under the conditions shown in Table 1 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, it was filtered with a filter having an opening of 200 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- Example 4 A synthetic amorphous silica powder was obtained in the same manner as in Example 1 except that a silica powder having an average particle diameter D 50 of 900 ⁇ m was obtained and that spheroidization was performed under the conditions shown in Table 1 below. .
- Example 5 12 mol of ultrapure water is prepared for 1 mol of fumed silica having an average particle diameter D 50 of 0.020 ⁇ m and a specific surface area of 90 m 2 / g.
- the prepared ultrapure water was put in a container, and fumed silica was added while stirring at a temperature of 30 ° C. in a nitrogen atmosphere. After the fumed silica was added, stirring was continued for 2 hours to form a siliceous gel. At this time, the stirring speed was 20 rpm.
- the siliceous gel is transferred to a drying container, put in a dryer, and dried at a temperature of 250 ° C. for 15 hours while flowing nitrogen at a flow rate of 1.0 L / min.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm, and the roll rotation speed was adjusted to 25 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 50 ⁇ m and an opening of 150 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 95 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the obtained silica powder without firing under the conditions shown in Table 1 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- Example 6 an amount of ultrapure water corresponding to 60 mol was prepared with respect to 1 mol of silicon tetrachloride. This ultrapure water was placed in a container, and hydrolyzed by adding silicon tetrachloride while stirring at a temperature of 30 ° C. in a nitrogen atmosphere. Stirring was continued for 4 hours after the addition of silicon tetrachloride to produce a siliceous gel. At this time, the stirring speed was 250 rpm. Next, the siliceous gel was transferred to a drying container, put in a dryer, and dried at a temperature of 250 ° C. for 24 hours while flowing nitrogen at a flow rate of 10 L / min into the dryer to obtain a dry powder. .
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm and the roll rotation speed to 150 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 50 ⁇ m and an opening of 200 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 116 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the obtained silica powder without firing under the conditions shown in Table 1 below. Specifically, first, argon as a working gas was introduced from the gas introduction tube 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the powder after washing was placed in a drying container, and kept at a temperature of 150 ° C. for 48 hours while flowing nitrogen at a flow rate of 15 L / min in the dryer to obtain a synthetic amorphous silica powder.
- Example 7 First, 1 mol of ultrapure water and 1 mol of ethanol were prepared with respect to 1 mol of tetramethoxysilane. The prepared ultrapure water and ethanol were put in a container, and tetramethoxysilane was added and hydrolyzed while stirring at a temperature of 60 ° C. in a nitrogen atmosphere. After stirring for 60 minutes after the addition of tetramethoxysilane, 25 mol of ultrapure water was further added to 1 mol of tetramethoxylane, and stirring was continued for 6 hours to produce a siliceous gel. At this time, the stirring speed was 100 rpm.
- the siliceous gel was transferred to a drying container, put into a dryer, and dried at a temperature of 150 ° C. for 48 hours while flowing nitrogen at a flow rate of 20 L / min into the dryer to obtain a dry powder. .
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm, and the roll rotation speed was adjusted to 55 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 50 ⁇ m and an opening of 200 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 118 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the obtained silica powder without firing under the conditions shown in Table 1 below. Specifically, first, argon as a working gas was introduced from the gas introduction tube 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the powder after washing was placed in a drying container, and kept at a temperature of 150 ° C. for 48 hours while flowing nitrogen at a flow rate of 15 L / min in the dryer to obtain a synthetic amorphous silica powder.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm and the roll rotation number was 40 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 100 ⁇ m and an opening of 150 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 128 ⁇ m.
- the pulverized powder is put into a firing container, this firing container is put into a firing furnace, and kept at a temperature of 1200 ° C. for 48 hours while flowing at a flow rate of nitrogen of 10 L / min.
- a synthetic amorphous silica powder having a particle size D 50 of 91 ⁇ m was obtained.
- the silica powder not subjected to the spheroidizing treatment was used as Comparative Example 6.
- the siliceous gel was transferred to a drying container, put in a dryer, and dried at a temperature of 200 ° C. for 48 hours while flowing nitrogen at a flow rate of 20 L / min into the dryer to obtain a dry powder. .
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.4 mm, and the roll rotation speed was adjusted to 100 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 400 ⁇ m and an opening of 500 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 469 ⁇ m.
- the pulverized powder is put into a firing container, this firing container is put into a firing furnace, and kept at a temperature of 1200 ° C. for 48 hours while flowing at a flow rate of argon of 10 L / min.
- a synthetic amorphous silica powder having a particle size D 50 of 328 ⁇ m was obtained.
- the silica powder not subjected to the spheroidizing treatment was used as Comparative Example 7.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.9 mm, and the roll rotation speed was adjusted to 150 rpm.
- the pulverized dry powder was classified using a vibration sieve having an opening of 800 ⁇ m and an opening of 900 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 849 ⁇ m.
- the pulverized powder is put into a firing container, this firing container is put into a firing furnace, and kept at a temperature of 1200 ° C. for 48 hours while flowing at a flow rate of argon of 10 L / min.
- a synthetic amorphous silica powder having a particle size D 50 of 594 ⁇ m was obtained.
- the silica powder not subjected to the spheroidizing treatment was used as Comparative Example 8.
- Example 8 12 mol of ultrapure water is prepared for 1 mol of fumed silica having an average particle diameter D 50 of 0.020 ⁇ m and a specific surface area of 90 m 2 / g.
- the prepared ultrapure water was put in a container, and fumed silica was added while stirring at a temperature of 30 ° C. in a nitrogen atmosphere. After the fumed silica was added, stirring was continued for 2 hours to form a siliceous gel. At this time, the stirring speed was 20 rpm. Next, the siliceous gel was transferred to a drying container, put into a dryer, and dried at a temperature of 250 ° C.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm, and the roll rotation speed was adjusted to 25 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 75 ⁇ m and an opening of 200 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 140 ⁇ m.
- the granulated powder was put in a quartz container and baked at 1250 ° C. for 48 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 97 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- Example 9 5 mol of ultrapure water is prepared for 1 mol of fumed silica having an average particle diameter D 50 of 0.030 ⁇ m and a specific surface area of 50 m 2 / g.
- the prepared ultrapure water was put in a container, and fumed silica was added while stirring at a temperature of 20 ° C. in a nitrogen atmosphere. After the fumed silica was added, stirring was continued for 0.5 hours to produce a siliceous gel. At this time, the stirring speed was 30 rpm. Next, the siliceous gel was transferred to a drying container, put in a dryer, and dried at a temperature of 200 ° C.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.3 mm, and the roll rotation speed was adjusted to 100 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 75 ⁇ m and an opening of 250 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 155 ⁇ m.
- the granulated powder was put in a quartz container and baked at 1300 ° C. for 24 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 105 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the powder after washing is put in a drying container, this drying container is put into a dryer, and nitrogen is supplied into the dryer at a flow rate of 1 L / min, and kept at a temperature of 400 ° C. for 12 hours.
- a synthetic amorphous silica powder was obtained.
- Example 10 30 mol of ultrapure water is prepared for 1 mol of fumed silica having an average particle diameter D 50 of 0.007 ⁇ m and a specific surface area of 300 m 2 / g.
- the prepared ultrapure water was put in a container, and fumed silica was added while stirring while maintaining the temperature at 10 ° C. in an argon atmosphere. Stirring was continued for 6 hours after the fumed silica was added to produce a siliceous gel. At this time, the stirring speed was 50 rpm.
- the siliceous gel was transferred to a drying container, put into a dryer, and dried at a temperature of 300 ° C.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.5 mm, and the roll rotation speed was adjusted to 100 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 300 ⁇ m and an opening of 600 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 482 ⁇ m.
- the granulated powder was put in a quartz container and baked at 1350 ° C. for 72 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 342 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, it was filtered with a filter having an opening of 200 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- Example 11 15 mol of ultrapure water is prepared for 1 mol of fumed silica having an average particle diameter D 50 of 0.016 ⁇ m and a specific surface area of 130 m 2 / g.
- the prepared ultrapure water was put in a container, and fumed silica was added while stirring while keeping the temperature at 25 ° C. in an argon atmosphere. After the fumed silica was added, stirring was continued for 3 hours to produce a siliceous gel. At this time, the stirring speed was 15 rpm. Next, the siliceous gel was transferred to a drying container, put in a dryer, and dried at a temperature of 200 ° C.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 1.0 mm and the roll rotation speed was adjusted to 50 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 500 ⁇ m and an opening of 1500 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 1083 ⁇ m.
- the granulated powder was put in a quartz container and baked at 1450 ° C. for 72 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 725 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, it was filtered with a filter having an opening of 400 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- Example 12 an amount of ultrapure water corresponding to 60 mol was prepared with respect to 1 mol of silicon tetrachloride. This ultrapure water was placed in a container, and hydrolyzed by adding silicon tetrachloride while stirring at a temperature of 30 ° C. in a nitrogen atmosphere. Stirring was continued for 4 hours after the addition of silicon tetrachloride to produce a siliceous gel. At this time, the stirring speed was 250 rpm. Next, the siliceous gel was transferred to a drying container, put in a dryer, and dried at a temperature of 250 ° C. for 24 hours while flowing nitrogen at a flow rate of 10 L / min into the dryer to obtain a dry powder. .
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm and the roll rotation speed to 150 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 50 ⁇ m and an opening of 200 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 151 ⁇ m.
- the granulated powder was put in a quartz container and fired at 1400 ° C. for 36 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 111 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas introduction tube 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the powder after washing was placed in a drying container, and kept at a temperature of 150 ° C. for 48 hours while flowing nitrogen at a flow rate of 15 L / min in the dryer to obtain a synthetic amorphous silica powder.
- Example 13 First, 1 mol of ultrapure water and 1 mol of ethanol were prepared with respect to 1 mol of tetramethoxysilane. The prepared ultrapure water and ethanol were put in a container, and tetramethoxysilane was added and hydrolyzed while stirring at a temperature of 60 ° C. in a nitrogen atmosphere. After stirring for 60 minutes after the addition of tetramethoxysilane, 25 mol of ultrapure water was further added to 1 mol of tetramethoxylane, and stirring was continued for 6 hours to produce a siliceous gel. At this time, the stirring speed was 100 rpm.
- the siliceous gel was transferred to a drying container, put into a dryer, and dried at a temperature of 200 ° C. for 24 hours while flowing nitrogen at a flow rate of 20 L / min into the dryer to obtain a dry powder. .
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm, and the roll rotation speed was adjusted to 55 rpm.
- the pulverized dry powder was classified using a vibration sieve having an opening of 75 ⁇ m and an opening of 250 ⁇ m to obtain silica powder having an average particle diameter D 50 of 147 ⁇ m.
- the granulated powder was put in a quartz container and baked at 1200 ° C. for 72 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 107 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas introduction tube 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the powder after washing was put in a drying container, and kept at a temperature of 300 ° C. for 12 hours while flowing argon at a flow rate of 10 L / min in the dryer to obtain a synthetic amorphous silica powder.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm, and the roll rotation speed was adjusted to 25 rpm.
- the pulverized dry powder was classified using a vibration sieve having an opening of 75 ⁇ m and an opening of 250 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 144 ⁇ m.
- the granulated powder was put in a quartz container and baked at 1200 ° C. for 36 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 101 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.3 mm, and the roll rotation speed was adjusted to 100 rpm.
- the pulverized dry powder was classified using a vibration sieve having an opening of 75 ⁇ m and an opening of 250 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 174 ⁇ m.
- the granulated powder was put into a quartz container and baked at 1250 ° C. for 24 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 115 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the powder after washing is put in a drying container, this drying container is put into a dryer, and nitrogen is supplied into the dryer at a flow rate of 1 L / min, and kept at a temperature of 400 ° C. for 12 hours.
- a synthetic amorphous silica powder was obtained.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.5 mm, and the roll rotation speed was adjusted to 100 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 300 ⁇ m and an opening of 700 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 516 ⁇ m.
- the granulated powder was put in a quartz container and baked at 1350 ° C. for 72 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 361 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, it was filtered with a filter having an opening of 200 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- ⁇ Comparative Example 12> 15 mol of ultrapure water is prepared for 1 mol of fumed silica having an average particle diameter D 50 of 0.016 ⁇ m and a specific surface area of 130 m 2 / g.
- the prepared ultrapure water was put in a container, and fumed silica was added while stirring while keeping the temperature at 25 ° C. in an argon atmosphere. After the fumed silica was added, stirring was continued for 4 hours to produce a siliceous gel. At this time, the stirring speed was 15 rpm. Next, the siliceous gel was transferred to a drying container, put in a dryer, and dried at a temperature of 200 ° C.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 1.0 mm and the roll rotation speed was adjusted to 50 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 500 ⁇ m and an opening of 1500 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 1030 ⁇ m.
- the granulated powder was put in a quartz container and fired at 1450 ° C. for 72 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 711 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, it was filtered with a filter having an opening of 400 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 1.0 mm and the roll rotation speed was adjusted to 40 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 500 ⁇ m and an opening of 1500 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 1030 ⁇ m.
- the granulated powder was put in a quartz container and fired at 1450 ° C. for 72 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 711 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas supply pipe 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, it was filtered with a filter having an opening of 400 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm and the roll rotation speed to 150 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 50 ⁇ m and an opening of 200 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 165 ⁇ m.
- the granulated powder was put in a quartz container and baked at 1350 ° C. for 24 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 112 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas introduction tube 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the powder after washing was placed in a drying container, and kept at a temperature of 150 ° C. for 48 hours while flowing nitrogen at a flow rate of 15 L / min in the dryer to obtain a synthetic amorphous silica powder.
- the siliceous gel was transferred to a drying container, put into a dryer, and dried at a temperature of 200 ° C. for 24 hours while flowing nitrogen at a flow rate of 20 L / min into the dryer to obtain a dry powder. .
- the dried powder was taken out from the dryer and pulverized using a roll crusher. At this time, the roll gap was adjusted to 0.2 mm, and the roll rotation speed was adjusted to 150 rpm.
- the pulverized dry powder was classified using a vibrating sieve having an opening of 50 ⁇ m and an opening of 200 ⁇ m to obtain a silica powder having an average particle diameter D 50 of 159 ⁇ m.
- the granulated powder was put into a quartz container and baked at 1350 ° C. for 24 hours in an air atmosphere to obtain a silica powder having an average particle diameter D 50 of 111 ⁇ m.
- the apparatus 30 shown in FIG. 5 was used to spheroidize the silica powder obtained after the firing under the conditions shown in Table 2 below. Specifically, first, argon as a working gas was introduced from the gas introduction tube 38 of the apparatus 30, and a high frequency was applied to the plasma torch 31 to generate plasma. After the plasma was stabilized, oxygen was gradually introduced to generate an argon-oxygen plasma. The obtained silica powder is introduced into the argon-oxygen plasma from the raw material supply pipe 37, the silica powder is melted, the melted particles are dropped, and the dropped particles are recovered by the recovery unit 33. Thereby, the spheroidized silica powder 41 was obtained.
- the powder and ultrapure water were put in a cleaning container and ultrasonic cleaning was performed. After ultrasonic cleaning, the mixture was filtered with a filter having an opening of 50 ⁇ m. This operation was repeated until there was no fine powder adhering to the surface of the silica powder particles.
- the powder after washing was placed in a drying container, and kept at a temperature of 150 ° C. for 48 hours while flowing nitrogen at a flow rate of 15 L / min in the dryer to obtain a synthetic amorphous silica powder.
- Average particle diameter D 50 The median value of particle distribution (diameter) measured by a laser diffraction / scattering particle distribution measuring apparatus (model name: HORIBA LA-950) was measured three times, and this average value was calculated.
- BET specific surface area Measured by the BET three-point method using a measuring device (QUANTACHROME AUTOSORB-1 MP).
- the slope A was obtained from the nitrogen adsorption amount with respect to three relative pressure points, and the specific surface area value was obtained from the BET equation.
- the nitrogen adsorption amount was measured under conditions of 150 ° C. and 60 minutes.
- Theoretical specific surface area 6 / (D ⁇ ⁇ ) (1)
- Theoretical specific surface area of the powder 2.73 / D 50 (2)
- Soot particle space ratio The obtained powder is embedded in a resin and polished to obtain a powder cross section.
- the powder cross section was observed by SEM (scanning electron microscope).
- SEM scanning electron microscope
- Intraparticle space ratio total area of intraparticle space / total area of particle breakage (4) (7)
- Circularity Measured twice with a particle size / shape distribution measuring instrument (Seishin Corporation PITA-1) shown in FIG. 4, and the average value was calculated. Specifically, first, the powder was dispersed in a liquid, and the liquid was allowed to flow into the planar extension flow cell 51. 200 powder particles 52 moving into the plane extension flow cell 51 were recorded as an image by the objective lens 53, and the circularity was calculated from this recorded image and the following equation (3).
- S represents the area of the photographed recorded image in the particle projection diagram
- L represents the perimeter of the particle projection diagram. The average value of the 200 particles calculated in this way was defined as the circularity of the powder.
- Circularity 4 ⁇ S / L 2 (3) (8) Undissolved rate: The ratio of the angular powder particles as shown in FIG. 6 was calculated from the above-described particle projection diagram of 200 powder particles.
- the section of 20 mm in length and 20 mm in width at 20 mm height of the block material is cut out and polished, and the number of bubbles observed in the area of 2 mm depth and 2 mm width is evaluated from the surface (cross section) of the block material. did.
- Na, K, Ca, Fe, Al, P Synthetic amorphous silica powder is thermally decomposed with hydrofluoric acid and sulfuric acid, and after heating and condensing, a constant volume liquid is prepared using dilute nitric acid, and high frequency induction is performed. Analysis was performed with a coupled plasma mass spectrometer (model name: SII Nanotechnology, SPQ9000).
- Examples 1 to 7 are hydroxyl groups that can be gas components that cause generation or expansion of bubbles in a synthetic silica glass product at a high temperature and reduced pressure as compared with Comparative Examples 1 to 8. And the carbon concentration is relatively low.
- the synthetic amorphous silica powder made from the raw material obtained by reacting silicon tetrachloride in the liquid had a carbon concentration of less than 2 ppm and was obtained from an organic silicon compound.
- Synthetic amorphous silica powder made from a raw material has a chlorine concentration of less than 2 ppm
- synthetic amorphous silica powder made from fumed silica has a carbon concentration of less than 2 ppm and a chlorine concentration of less than 2 ppm. It turns out that it is.
- the synthetic amorphous silica powder of the present invention is used as a raw material for producing synthetic silica glass products such as crucibles and jigs used for producing single crystals for semiconductor applications.
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Abstract
Description
本明細書中、粉末の理論比表面積とは、上記式(1)において、Dを粉末の平均粒径D50、ρを真密度2.20g/cm3と仮定した理論真密度から算出した値である。即ち、粉末の理論比表面積は、次の式(2)から算出される。
BET比表面積を平均粒径D50から算出した理論比表面積で割った値が大きくなると、比表面積が大きくなり、不可避のガス吸着量が大きくなる。このうち、上記値は、1.00~1.15の範囲が好ましい。上記値が、1.15より大きいと、気泡の発生は又は膨張の低減効果が小さい。
式(3)中、Sは撮影した粒子投影図の面積、Lは粒子投影図の周囲長を表す。本明細書中、粉末の円形度とは、上記式(3)から算出された粉末粒子200個の平均値である。粉末の円形度が0.75未満では、気泡の発生又は膨張の低減効果が小さい。このうち、粉末の円形度は、0.80~1.00の範囲が好ましい。
また、合成非晶質シリカ粉末の平均粒径D50は、10~2000μmであり、50~1000μmの範囲内であることが好ましい。下限値未満では、粉末粒子間の空間が小さく、この空間に存在している気体が抜けにくいため、小さな気泡が残りやすく、一方、上限値を越えると、粉末粒子間の空間が大きすぎて、大きな気泡が残りやすいためである。このうち、平均粒径D50は、80~600μmの範囲内であることが特に好ましい。なお、本明細書中、平均粒径D50とは、レーザー回折散乱式粒子分布測定装置(型式名:HORIBA LA-950)によって測定した粒子分布(直径)の中央値を3回測定し、この平均値をいう。合成非晶質シリカ粉末のかさ密度は、1.00g/cm3以上であることが好ましい。下限値未満では、粉末粒子間の空間が大きすぎて、大きな気泡が残りやすく、一方、上限値を越えると、粉末粒子間の空間が小さいために、この空間に存在している気体が抜けにくく、小さな気泡が残りやすいからである。このうち、かさ密度は、1.20~1.50g/cm3範囲内であることが特に好ましい。
先ず、四塩化珪素1molに対して、55.6molに相当する量の超純水を準備した。この超純水を容器内に入れ、窒素雰囲気にて、温度を25℃に保持して攪拌しながら、四塩化珪素を添加して加水分解させた。四塩化珪素を添加してから2時間攪拌を継続して、シリカ質のゲルを生成させた。このとき、攪拌速度は100rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量で窒素を流しながら、200℃の温度で24時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数を40rpmに調整して行った。粉砕した乾燥粉を目開き100μm及び目開き150μmの振動フルイを用いて分級し、平均粒径D50が124μmのシリカ粉末を得た。
先ず、テトラメトキシシラン1molに対して、超純水2mol、エタノール2molを準備する。準備した超純水、エタノールを容器内に入れ、窒素雰囲気にて、温度を60℃に保持して攪拌しながら、テトラメトキシシランを添加して加水分解させた。テトラメトキシシランを添加してから60分間、撹拌した後、テトラメトキシラン1molに対して30molの超純水を更に添加し、5時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は100rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に20L/minの流量で窒素を流しながら、200℃の温度で48時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数を55rpmに調整して行った。粉砕した乾燥粉を目開き100μm及び目開き150μmの振動フルイを用いて分級し、平均粒径D50が135μmのシリカ粉末を得た。
先ず、平均粒径D50が0.030μm、比表面積が50m2/gのヒュームドシリカ1molに対して、超純水10molを準備する。準備した超純水を容器内に入れ、窒素雰囲気にて、温度を25℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから3時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は30rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量で窒素を流しながら、300℃の温度で12時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.5mm、ロール回転数を100rpmに調整して行った。粉砕した乾燥粉を目開き400μm及び目開き500μmの振動フルイを用いて分級し、平均粒径D50が459μmのシリカ粉末を得た。
平均粒径D50が900μmのシリカ粉末を得たこと、及び次の表1に示す条件で球状化処理を施したこと以外は、実施例1と同様に、合成非晶質シリカ粉末を得た。
先ず、平均粒径D50が0.020μm、比表面積が90m2/gのヒュームドシリカ1molに対して、超純水12molを準備する。準備した超純水を容器内に入れ、窒素雰囲気にて、温度を30℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから2時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は20rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に1.0L/minの流量で窒素を流しながら、250℃の温度で15時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数を25rpmに調整して行った。粉砕した乾燥粉を目開き50μm及び目開き150μmの振動フルイを用いて分級し、平均粒径D50が95μmのシリカ粉末を得た。
先ず、四塩化珪素1molに対して、60molに相当する量の超純水を準備した。この超純水を容器内に入れ、窒素雰囲気にて、温度を30℃に保持して攪拌しながら、四塩化珪素を添加して加水分解させた。四塩化珪素を添加してから4時間攪拌を継続して、シリカ質のゲルを生成させた。このとき、攪拌速度は250rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量で窒素を流しながら、250℃の温度で24時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数150rpmに調整して行った。粉砕した乾燥粉を目開き50μm及び目開き200μmの振動フルイを用いて分級し、平均粒径D50が116μmのシリカ粉末を得た。
先ず、テトラメトキシシラン1molに対して、超純水1mol、エタノール1molを準備した。準備した超純水、エタノールを容器内に入れ、窒素雰囲気にて、温度を60℃に保持して攪拌しながら、テトラメトキシシランを添加して加水分解させた。テトラメトキシシランを添加してから60分間、撹拌した後、テトラメトキシラン1molに対して25molの超純水を更に添加し、6時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は100rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に20L/minの流量で窒素を流しながら、150℃の温度で48時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数を55rpmに調整して行った。粉砕した乾燥粉を目開き50μm及び目開き200μmの振動フルイを用いて分級し、平均粒径D50が118μmのシリカ粉末を得た。
次の表1に示す条件で球状化処理を施したこと以外は、実施例1と同様に、合成非晶質シリカ粉末を得た。
次の表1に示す条件で球状化処理を施したこと以外は、実施例2と同様に、合成非晶質シリカ粉末を得た。
次の表1に示す条件で球状化処理を施したこと以外は、実施例3と同様に、合成非晶質シリカ粉末を得た。
次の表1に示す条件で球状化処理を施したこと以外は、実施例3と同様に、合成非晶質シリカ粉末を得た。
次の表1に示す条件で球状化処理を施したこと以外は、実施例4と同様に、合成非晶質シリカ粉末を得た。
先ず、四塩化珪素1molに対して、55.6molに相当する量の超純水を準備した。この超純水を容器内に入れ、窒素雰囲気にて、温度を25℃に保持して攪拌しながら、四塩化珪素を添加して加水分解させた。四塩化珪素を添加してから2時間攪拌を継続して、シリカ質のゲルを生成させた。このとき、攪拌速度は100rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量で窒素を流しながら、200℃の温度で24時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数40rpmに調整して行った。粉砕した乾燥粉を目開き100μm及び目開き150μmの振動フルイを用いて分級し、平均粒径D50が128μmのシリカ粉末を得た。
先ず、テトラメトキシシラン1molに対して、超純水2mol、エタノール2molを準備する。準備した超純水、エタノールを容器内に入れ、窒素雰囲気にて、温度を60℃に保持して攪拌しながら、テトラメトキシシランを添加して加水分解させた。テトラメトキシシランを添加してから60分間、撹拌した後、テトラメトキシラン1molに対して30molの超純水を更に添加し、6時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は100rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に20L/minの流量で窒素を流しながら、200℃の温度で48時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.4mm、ロール回転数を100rpmに調整して行った。粉砕した乾燥粉を目開き400μm及び目開き500μmの振動フルイを用いて分級し、平均粒径D50が469μmのシリカ粉末を得た。
先ず、平均粒径D50が0.030μm、比表面積が50m2/gのヒュームドシリカ1molに対して、超純水10molを準備する。準備した超純水を容器内に入れ、窒素雰囲気にて、温度を25℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから3時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は30rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量で窒素を流しながら、300℃の温度で12時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.9mm、ロール回転数を150rpmに調整して行った。粉砕した乾燥粉を目開き800μm及び目開き900μmの振動フルイを用いて分級し、平均粒径D50が849μmのシリカ粉末を得た。
先ず、平均粒径D50が0.020μm、比表面積が90m2/gのヒュームドシリカ1molに対して、超純水12molを準備する。準備した超純水を容器内に入れ、窒素雰囲気にて、温度を30℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから2時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は20rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量でアルゴンを流しながら、250℃の温度で15時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数を25rpmに調整して行った。粉砕した乾燥粉を目開き75μm及び目開き200μmの振動フルイを用いて分級し、平均粒径D50が140μmのシリカ粉末を得た。
先ず、平均粒径D50が0.030μm、比表面積が50m2/gのヒュームドシリカ1molに対して、超純水5molを準備する。準備した超純水を容器内に入れ、窒素雰囲気にて、温度を20℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから0.5時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は30rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に15L/minの流量で窒素を流しながら、200℃の温度で48時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.3mm、ロール回転数を100rpmに調整して行った。粉砕した乾燥粉を目開き75μm及び目開き250μmの振動フルイを用いて分級し、平均粒径D50が155μmのシリカ粉末を得た。
先ず、平均粒径D50が0.007μm、比表面積が300m2/gのヒュームドシリカ1molに対して、超純水30molを準備する。準備した超純水を容器内に入れ、アルゴン雰囲気にて、温度を10℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから6時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は50rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に15L/minの流量で窒素を流しながら、300℃の温度で12時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.5mm、ロール回転数を100rpmに調整して行った。粉砕した乾燥粉を目開き300μm及び目開き600μmの振動フルイを用いて分級し、平均粒径D50が482μmのシリカ粉末を得た。
先ず、平均粒径D50が0.016μm、比表面積が130m2/gのヒュームドシリカ1molに対して、超純水15molを準備する。準備した超純水を容器内に入れ、アルゴン雰囲気にて、温度を25℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから3時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は15rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量でアルゴンを流しながら、200℃の温度で36時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を1.0mm、ロール回転数を50rpmに調整して行った。粉砕した乾燥粉を目開き500μm及び目開き1500μmの振動フルイを用いて分級し、平均粒径D50が1083μmのシリカ粉末を得た。
先ず、四塩化珪素1molに対して、60molに相当する量の超純水を準備した。この超純水を容器内に入れ、窒素雰囲気にて、温度を30℃に保持して攪拌しながら、四塩化珪素を添加して加水分解させた。四塩化珪素を添加してから4時間攪拌を継続して、シリカ質のゲルを生成させた。このとき、攪拌速度は250rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量で窒素を流しながら、250℃の温度で24時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数150rpmに調整して行った。粉砕した乾燥粉を目開き50μm及び目開き200μmの振動フルイを用いて分級し、平均粒径D50が151μmのシリカ粉末を得た。
先ず、テトラメトキシシラン1molに対して、超純水1mol、エタノール1molを準備した。準備した超純水、エタノールを容器内に入れ、窒素雰囲気にて、温度を60℃に保持して攪拌しながら、テトラメトキシシランを添加して加水分解させた。テトラメトキシシランを添加してから60分間、撹拌した後、テトラメトキシラン1molに対して25molの超純水を更に添加し、6時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は100rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に20L/minの流量で窒素を流しながら、200℃の温度で24時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数を55rpmに調整して行った。粉砕した乾燥粉を目開き75μm及び目開き250μmの振動フルイを用いて分級し、平均粒径D50が147μmのシリカ粉末を得た。
先ず、平均粒径D50が0.020μm、比表面積が90m2/gのヒュームドシリカ1molに対して、超純水12molを準備する。準備した超純水を容器内に入れ、窒素雰囲気にて、温度を30℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから2時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は20rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量でアルゴンを流しながら、250℃の温度で15時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数を25rpmに調整して行った。粉砕した乾燥粉を目開き75μm及び目開き250μmの振動フルイを用いて分級し、平均粒径D50が144μmのシリカ粉末を得た。
先ず、平均粒径D50が0.030μm、比表面積が50m2/gのヒュームドシリカ1molに対して、超純水5molを準備する。準備した超純水を容器内に入れ、窒素雰囲気にて、温度を20℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから0.5時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は30rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に15L/minの流量で窒素を流しながら、200℃の温度で48時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.3mm、ロール回転数を100rpmに調整して行った。粉砕した乾燥粉を目開き75μm及び目開き250μmの振動フルイを用いて分級し、平均粒径D50が174μmのシリカ粉末を得た。
先ず、平均粒径D50が0.007μm、比表面積が300m2/gのヒュームドシリカ1molに対して、超純水30molを準備する。準備した超純水を容器内に入れ、窒素雰囲気にて、温度を10℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから6時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は50rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に15L/minの流量で窒素を流しながら、300℃の温度で12時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.5mm、ロール回転数を100rpmに調整して行った。粉砕した乾燥粉を目開き300μm及び目開き700μmの振動フルイを用いて分級し、平均粒径D50が516μmのシリカ粉末を得た。
先ず、平均粒径D50が0.016μm、比表面積が130m2/gのヒュームドシリカ1molに対して、超純水15molを準備する。準備した超純水を容器内に入れ、アルゴン雰囲気にて、温度を25℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから4時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は15rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量でアルゴンを流しながら、200℃の温度で36時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を1.0mm、ロール回転数を50rpmに調整して行った。粉砕した乾燥粉を目開き500μm及び目開き1500μmの振動フルイを用いて分級し、平均粒径D50が1030μmのシリカ粉末を得た。
先ず、平均粒径D50が0.016μm、比表面積が130m2/gのヒュームドシリカ1molに対して、超純水15molを準備する。準備した超純水を容器内に入れ、アルゴン雰囲気にて、温度を25℃に保持して攪拌しながら、ヒュームドシリカを添加した。ヒュームドシリカを添加してから3時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は15rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量でアルゴンを流しながら、200℃の温度で36時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を1.0mm、ロール回転数を40rpmに調整して行った。粉砕した乾燥粉を目開き500μm及び目開き1500μmの振動フルイを用いて分級し、平均粒径D50が1030μmのシリカ粉末を得た。
先ず、四塩化珪素1molに対して、60molに相当する量の超純水を準備した。この超純水を容器内に入れ、窒素雰囲気にて、温度を30℃に保持して攪拌しながら、四塩化珪素を添加して加水分解させた。四塩化珪素を添加してから4時間攪拌を継続して、シリカ質のゲルを生成させた。このとき、攪拌速度は250rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に10L/minの流量で窒素を流しながら、250℃の温度で24時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数150rpmに調整して行った。粉砕した乾燥粉を目開き50μm及び目開き200μmの振動フルイを用いて分級し、平均粒径D50が165μmのシリカ粉末を得た。
先ず、テトラメトキシシラン1molに対して、超純水1mol、エタノール1molを準備した。準備した超純水、エタノールを容器内に入れ、窒素雰囲気にて、温度を60℃に保持して攪拌しながら、テトラメトキシシランを添加して加水分解させた。テトラメトキシシランを添加してから60分間、撹拌した後、テトラメトキシラン1molに対して25molの超純水を更に添加し、6時間攪拌を継続し、シリカ質のゲルを生成させた。このとき、攪拌速度は100rpmとした。次に、上記シリカ質のゲルを乾燥用容器に移しこれを乾燥機に入れ、乾燥機内に20L/minの流量で窒素を流しながら、200℃の温度で24時間乾燥させて乾燥粉を得た。この乾燥粉を乾燥機から取り出し、ロールクラッシャーを用いて粉砕した。このときロール隙間を0.2mm、ロール回転数を150rpmに調整して行った。粉砕した乾燥粉を目開き50μm及び目開き200μmの振動フルイを用いて分級し、平均粒径D50が159μmのシリカ粉末を得た。
粉末の理論比表面積=2.73/D50 (2)
(4) BET比表面積/理論比表面積:上記測定したBET比表面積及び理論比表面積から算出した。
(7) 円形度:図4に示す粒度・形状分布測定器(株式会社セイシン企業 PITA-1)にて2回測定し、この平均値を算出した。具体的には、先ず、粉末を液体に分散させて、この液体を平面伸張流動セル51へ流した。平面伸張流動セル51内に移動する粉末粒子52の200個を、対物レンズ53にて画像として記録し、この記録画像及び次の式(3)から円形度を算出した。式(3)中、Sは撮影した記録画像の粒子投影図における面積、Lは粒子投影図の周囲長を表す。このようにして算出された粒子200個の平均値を粉末の円形度とした。
(8) 未溶解率:前述の粉末粒子200個の粒子投影図で、図6に示すような、角ばっている粉末粒子が含まれる割合を算出した。
実施例1~13及び比較例1~15で得られた粉末を用いて、縦20mm×横20mm×高さ40mmの直方体のブロック材をそれぞれ製造し、ブロック材に発生した気泡の個数を評価した。この結果を次の表3又は表4に示す。具体的には、カーボンルツボに、粉末を入れ、これを2.0×104Pa真空雰囲気下でカーボンヒータにて2200℃に加熱し、48時間保持することによりブロック材を製造した。このブロック材を、5.0×102Pa真空雰囲気下で1600℃の温度で48時間の熱処理を行った。熱処理後、ブロック材の高さ20mmでの縦20mm×横20mmの断面の切り出し、研磨を行い、ブロック材の表面(断面)から、深さ2mm、幅2mm領域で観察された気泡の個数を評価した。
実施例1~13及び比較例1~15で得られた粉末の不純物濃度を以下の(1)~(5)の方法により分析又は測定した。その結果を次の表5又は表6に示す。
Claims (13)
- 造粒されたシリカ粉末に球状化処理を施した後、洗浄し乾燥して得られた平均粒径D50が10~2000μmの合成非晶質シリカ粉末であって、
BET比表面積を平均粒径D50から算出した理論比表面積で割った値が1.00~1.35、真密度が2.10~2.20g/cm3、粒子内空間率が0~0.05、円形度が0.75~1.00及び未溶解率が0.00~0.25である合成非晶質シリカ粉末。 - 前記造粒されたシリカ粉末を焼成した後、前記球状化処理が施された合成非晶質シリカ粉末であって、
炭素濃度が2ppm未満又は塩素濃度が2ppm未満のいずれか一方或いはその双方を満たす請求項1記載の合成非晶質シリカ粉末。 - 前記造粒されたシリカ粉末が、四塩化珪素を加水分解させてシリカ質のゲルを生成させ、このシリカ質のゲルを乾燥して乾燥粉とし、この乾燥粉を粉砕した後、分級することにより得られたシリカ粉末であって、
炭素濃度が2ppm未満である請求項2記載の合成非晶質シリカ粉末。 - 前記造粒されたシリカ粉末が、有機系シリコン化合物を加水分解させてシリカ質のゲルを生成させ、このシリカ質のゲルを乾燥して乾燥粉とし、この乾燥粉を粉砕した後、分級することにより得られたシリカ粉末であって、
塩素濃度が2ppm未満である請求項2記載の合成非晶質シリカ粉末。 - 前記造粒されたシリカ粉末が、ヒュームドシリカを用いてシリカ質のゲルを生成させ、このシリカ質のゲルを乾燥して乾燥粉とし、この乾燥粉を粉砕した後、分級することにより得られたシリカ粉末であって、
炭素濃度が2ppm未満、塩素濃度が2ppm未満である請求項2記載の合成非晶質シリカ粉末。 - シリカ質のゲルを生成させ、このシリカ質のゲルを乾燥して乾燥粉とし、この乾燥粉を粉砕した後、分級することによりシリカ粉末を得る造粒工程と、
所定の高周波出力でプラズマを発生させたプラズマトーチ内に所定の供給速度で前記造粒工程で得られたシリカ粉末を投入し、2000℃から二酸化珪素の沸点までの温度で加熱し、溶融させる熱プラズマによる球状化工程と、
前記球状化工程後の球状化シリカ粉末表面に付着している微粉を取り除く洗浄工程と、
前記洗浄工程後のシリカ粉末を乾燥する乾燥工程と
をこの順に含み、
前記球状化工程における高周波出力(W)をA、シリカ粉末の供給速度(kg/hr)をBとするとき、前記高周波出力Aが90kW以上の条件で、かつA/B(W・hr/kg)の値が1.0×104以上になるように調整して行われ、
平均粒径D50が10~2000μm、BET比表面積を平均粒径D50から算出した理論比表面積で割った値が1.00~1.35、真密度が2.10~2.20g/cm3、粒子内空間率が0~0.05、円形度が0.75~1.00及び未溶解率が0.00~0.25である合成非晶質シリカ粉末を得る
ことを特徴とする合成非晶質シリカ粉末の製造方法。 - 前記造粒工程が、四塩化珪素を加水分解させてシリカ質のゲルを生成させ、このシリカ質のゲルを乾燥して乾燥粉とし、この乾燥粉を粉砕した後、分級することにより平均粒径D50が10~3000μmのシリカ粉末を得る工程である請求項6記載の合成非晶質シリカ粉末の製造方法。
- 前記造粒工程が、有機系シリコン化合物を加水分解させてシリカ質のゲルを生成させ、このシリカ質のゲルを乾燥して乾燥粉とし、この乾燥粉を粉砕した後、分級することにより平均粒径D50が10~3000μmのシリカ粉末を得る工程である請求項6記載の合成非晶質シリカ粉末の製造方法。
- 前記造粒工程が、ヒュームドシリカを用いてシリカ質のゲルを生成させ、このシリカ質のゲルを乾燥して乾燥粉とし、この乾燥粉を粉砕した後、分級することにより平均粒径D50が10~3000μmのシリカ粉末を得る工程である請求項6記載の合成非晶質シリカ粉末の製造方法。
- シリカ質のゲルを生成させ、このシリカ質のゲルを乾燥して乾燥粉とし、この乾燥粉を粉砕した後、分級することによりシリカ粉末を得る造粒工程と、
前記造粒工程で得られたシリカ粉末を800~1450℃の温度で焼成する焼成工程と、
所定の高周波出力でプラズマを発生させたプラズマトーチ内に所定の供給速度で前記焼成工程で得られたシリカ粉末を投入し、2000℃から二酸化珪素の沸点までの温度で加熱し、溶融させる熱プラズマによる球状化工程と、
前記球状化工程後の球状化シリカ粉末表面に付着している微粉を取り除く洗浄工程と、
前記洗浄工程後のシリカ粉末を乾燥する乾燥工程と
をこの順に含み、
前記球状化工程における高周波出力(W)をA、シリカ粉末の供給速度(kg/hr)をBとするとき、前記高周波出力Aが90kW以上の条件で、かつA/B(W・hr/kg)の値が1.0×104以上になるように調整して行われ、
平均粒径D50が10~2000μm、BET比表面積を平均粒径D50から算出した理論比表面積で割った値が1.00~1.35、真密度が2.10~2.20g/cm3、粒子内空間率が0~0.05、円形度が0.75~1.00及び未溶解率が0.00~0.25であり、炭素濃度が2ppm未満又は塩素濃度が2ppm未満のいずれか一方或いはその双方を満たすことを特徴とする合成非晶質シリカ粉末の製造方法。 - 前記造粒工程が、四塩化珪素を加水分解させてシリカ質のゲルを生成させ、このシリカ質のゲルを乾燥して乾燥粉とし、この乾燥粉を粉砕した後、分級することにより平均粒径D50が10~3000μmのシリカ粉末を得る工程であるとき、
得られる合成非晶質シリカ粉末の炭素濃度が2ppm未満である請求項10記載の合成非晶質シリカ粉末の製造方法。 - 前記造粒工程が、有機系シリコン化合物を加水分解させてシリカ質のゲルを生成させ、このシリカ質のゲルを乾燥して乾燥粉とし、この乾燥粉を粉砕した後、分級することにより平均粒径D50が10~3000μmのシリカ粉末を得る工程であるとき、
得られる合成非晶質シリカ粉末の塩素濃度が2ppm未満である請求項10記載の合成非晶質シリカ粉末の製造方法。 - 前記造粒工程が、ヒュームドシリカを用いてシリカ質のゲルを生成させ、このシリカ質のゲルを乾燥して乾燥粉とし、この乾燥粉を粉砕した後、分級することにより平均粒径D50が10~3000μmのシリカ粉末を得る工程であるとき、
得られる合成非晶質シリカ粉末の炭素濃度が2ppm未満、塩素濃度が2ppm未満である請求項10記載の合成非晶質シリカ粉末の製造方法。
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EP10842212.2A EP2522629A4 (en) | 2010-01-07 | 2010-12-24 | SYNTHETIC AMORPHOUS SILICA POWDER AND PROCESS FOR PRODUCING THE SAME |
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US13/520,801 US9120678B2 (en) | 2010-01-07 | 2010-12-24 | Synthetic amorphous silica powder and method for producing same |
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JP6439782B2 (ja) * | 2016-12-27 | 2018-12-19 | 株式会社Sumco | 石英試料の分解方法、石英試料の金属汚染分析方法および石英部材の製造方法 |
JP2019182694A (ja) * | 2018-04-05 | 2019-10-24 | 三菱ケミカル株式会社 | 合成シリカガラス粉 |
KR102529239B1 (ko) | 2021-05-26 | 2023-05-08 | 주식회사 케이씨씨 | 미립 구상 방열 소재 및 이의 제조방법 |
KR102596829B1 (ko) * | 2023-04-28 | 2023-11-01 | 주식회사 이녹스에코엠 | 폐 실리콘 슬러지를 이용한 실리콘 분말의 제조방법 |
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JP2011157263A (ja) | 2011-08-18 |
CN102652109A (zh) | 2012-08-29 |
CN102652109B (zh) | 2016-02-24 |
US20120321895A1 (en) | 2012-12-20 |
JP2011157260A (ja) | 2011-08-18 |
US20150321939A1 (en) | 2015-11-12 |
JP5637149B2 (ja) | 2014-12-10 |
TW201132589A (en) | 2011-10-01 |
US9120678B2 (en) | 2015-09-01 |
JPWO2011083699A1 (ja) | 2013-05-13 |
US10023488B2 (en) | 2018-07-17 |
EP2522629A4 (en) | 2014-03-26 |
KR20120125232A (ko) | 2012-11-14 |
TWI488811B (zh) | 2015-06-21 |
EP2522629A1 (en) | 2012-11-14 |
KR101731665B1 (ko) | 2017-04-28 |
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