JP7567316B2 - Granulated silica powder and method for producing the same - Google Patents
Granulated silica powder and method for producing the same Download PDFInfo
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims description 215
- 239000000843 powder Substances 0.000 title claims description 107
- 239000000377 silicon dioxide Substances 0.000 title claims description 102
- 238000004519 manufacturing process Methods 0.000 title claims description 14
- 239000002245 particle Substances 0.000 claims description 72
- 238000005469 granulation Methods 0.000 claims description 18
- 230000003179 granulation Effects 0.000 claims description 18
- 239000011148 porous material Substances 0.000 claims description 15
- 239000011230 binding agent Substances 0.000 claims description 14
- SCPYDCQAZCOKTP-UHFFFAOYSA-N silanol Chemical compound [SiH3]O SCPYDCQAZCOKTP-UHFFFAOYSA-N 0.000 claims description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 239000010419 fine particle Substances 0.000 claims description 9
- 239000011361 granulated particle Substances 0.000 claims description 9
- 239000002994 raw material Substances 0.000 claims description 9
- 239000002002 slurry Substances 0.000 claims description 9
- 238000003980 solgel method Methods 0.000 claims description 8
- 239000007921 spray Substances 0.000 claims description 7
- 238000002360 preparation method Methods 0.000 claims description 6
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 5
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 5
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 5
- 238000001354 calcination Methods 0.000 claims 2
- 238000000034 method Methods 0.000 description 17
- 238000010304 firing Methods 0.000 description 16
- 238000000563 Verneuil process Methods 0.000 description 8
- 238000009826 distribution Methods 0.000 description 7
- 238000002844 melting Methods 0.000 description 7
- 230000008018 melting Effects 0.000 description 7
- 239000011521 glass Substances 0.000 description 5
- 238000001878 scanning electron micrograph Methods 0.000 description 5
- 239000010453 quartz Substances 0.000 description 4
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 4
- 230000001186 cumulative effect Effects 0.000 description 3
- 238000001095 inductively coupled plasma mass spectrometry Methods 0.000 description 3
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 3
- 229910052753 mercury Inorganic materials 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000007750 plasma spraying Methods 0.000 description 3
- 238000000790 scattering method Methods 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000007873 sieving Methods 0.000 description 3
- 239000000741 silica gel Substances 0.000 description 3
- 229910002027 silica gel Inorganic materials 0.000 description 3
- 229920001059 synthetic polymer Polymers 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000013307 optical fiber Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 239000011240 wet gel Substances 0.000 description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 206010040925 Skin striae Diseases 0.000 description 1
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000002612 dispersion medium Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920005615 natural polymer Polymers 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000012798 spherical particle Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000002604 ultrasonography Methods 0.000 description 1
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Description
本発明は、石英ガラス製の半導体治具や光ファイバーの製造に好適な造粒シリカ粉体に関する。 The present invention relates to granulated silica powder suitable for manufacturing semiconductor jigs and optical fibers made of quartz glass.
石英ガラス成型体の製造法として、ベルヌイ法やプラズマ溶射法が知られている。これらは、酸水素炎やプラズマの高温領域にシリカ粉体を落下、吹き付けなどの方法で通過させ、溶融状態として基材に添着、積層して石英ガラス成型体を製造する方法である。ここで用いられるシリカ粉体は、１００μｍ～２００μｍの粒径にそろえた天然石英粉体や、ゾル・ゲル法由来の合成石英粉体が用いられている。
例えば特許文献１には、ゾル・ゲル法により得られたシリカゲルを乾燥機内で乾燥したのち更に焼成することで、不純物及び発泡が抑えられた石英ガラス成型体を提供できる合成石英粉体を得ることが提案されている。
Known methods for manufacturing quartz glass molded bodies include the Verneuil process and plasma spraying. These methods involve passing silica powder through the high-temperature region of an oxyhydrogen flame or plasma by dropping, spraying, or other methods, and attaching and laminating the molten silica to a substrate to manufacture a quartz glass molded body. The silica powder used here is natural quartz powder with a particle size of 100 μm to 200 μm, or synthetic quartz powder derived from the sol-gel process.
For example,
しかしながら、従来使用されていた粒径１００μｍ～２００μｍの天然シリカ粉体や合成シリカ粉体は、その粒子形状は破砕状で流動性が悪い、粒子表面は溶融するが中心部は溶融不十分という粒子内での溶融粘度のムラが生じやすい、などの問題があり、これが脈理などの成型体の不均一性を生じる原因となっており、改善が望まれている。 However, conventionally used natural and synthetic silica powders with particle sizes of 100 μm to 200 μm have problems such as poor flowability due to their crushed particle shape, and a tendency for uneven melt viscosity within the particle, with the particle surface melting but the center not melting enough. This causes non-uniformity in the molded product, such as striae, and improvements are needed.
すなわち、ベルヌイ法やプラズマ溶射法で要求されるシリカ粉体の特性は、（Ｉ）適切な流動性（定量的に高温領域にフィードできる）、（ＩＩ）溶融が容易、（ＩＩＩ）無気泡の成型体ができる、（ＩＶ）成型体の均一性が得られる、というものである。要するに、高純度で流動性がよく、気泡の発生が抑えられた高均一性成型体が得られ得るシリカ粉体が求められている。
本発明は、このような要求を満たすシリカ粉体を提供することを課題とする。
That is, the properties of silica powder required for the Verneuil process and the plasma spraying process are (I) appropriate fluidity (capable of being quantitatively fed to a high temperature region), (II) ease of melting, (III) ability to produce a molded product without bubbles, and (IV) ability to obtain uniformity of the molded product. In short, there is a demand for silica powder that is high in purity, has good fluidity, and can produce a highly uniform molded product with suppressed bubble generation.
An object of the present invention is to provide a silica powder that satisfies such requirements.
本発明者らは、上記のような状況下鋭意検討を進め、特定粒径のシリカ微粒子粉体を造粒して製造した造粒シリカ粉体が、上記課題を解決できることを見出し、本発明を完成させた。本発明は以下のものを含む。 The inventors of the present invention have conducted intensive research under the above circumstances, and have found that a granulated silica powder produced by granulating silica fine particle powder of a specific particle size can solve the above problems, thus completing the present invention. The present invention includes the following.
（１）Ｄ５０粒径（メジアン径）が７５μｍ以上２００μｍ以下であり、安息角が２０度以上３５度以下であり、比表面積が０．３ｍ２／ｇ以上１０ｍ２／ｇ以下である造粒シリカ粉体であって、
前記造粒シリカ粉体が、粒子径１０μｍ以下の粒子を１５％以上４０％以下含む凝集粒子である造粒シリカ粉体。
（２）シラノール濃度が２００ｐｐｍ以下であり吸着水分量が１％以下である、（１）に記載の造粒シリカ粉体。
（３）Ｆｅ含有量が１ｐｐｍ以下、Ａｌ含有量が０．１ｐｐｍ以下、Ｔｉ含有量が０．０１ｐｐｍ以下である、（１）又は（２）に記載の造粒シリカ粉体。
（４）平均細孔径が１μｍ以上１０μｍである、（１）乃至（３）のいずれかに記載の造
粒シリカ粉体。
（５）粒子径１０μｍ以下の粒子を１５％以上４０％以下含み、ゾル・ゲル法により得られた原料シリカを準備する準備ステップ、
原料シリカをスラリー化し、バインダーを加えて噴霧造粒する造粒ステップ、及び
得られた造粒粒子を１０００℃以上１３００℃以下で焼成する焼成ステップ、を含む造粒シリカ粉体の製造方法。
（６）前記造粒ステップにおいて、スラリー化に用いる媒体が水であり、バインダーがポリビニルピロリドンである、（５）に記載の造粒シリカ粉体の製造方法。
(1) A granulated silica powder having a D50 particle size (median diameter) of 75 μm or more and 200 μm or less, an angle of repose of 20 degrees or more and 35 degrees or less, and a specific surface area of 0.3 m 2 /g or more and 10 m 2 /g or less,
The granulated silica powder is an agglomerated particle containing 15% to 40% particles with a particle diameter of 10 μm or less.
(2) A granulated silica powder according to (1), having a silanol concentration of 200 ppm or less and an adsorbed moisture content of 1% or less.
(3) A granulated silica powder according to (1) or (2), having an Fe content of 1 ppm or less, an Al content of 0.1 ppm or less, and a Ti content of 0.01 ppm or less.
(4) A granulated silica powder according to any one of (1) to (3), having an average pore diameter of 1 μm or more and 10 μm or less.
(5) preparing raw material silica obtained by a sol-gel method, the raw material silica containing particles having a particle diameter of 10 μm or less in an amount of 15% to 40%;
A method for producing granulated silica powder, comprising: a granulation step of forming a slurry of raw silica, adding a binder, and spray granulating the slurry; and a firing step of firing the resulting granulated particles at 1000°C or higher and 1300°C or lower.
(6) The method for producing granulated silica powder according to (5), wherein in the granulation step, the medium used for slurrying is water and the binder is polyvinylpyrrolidone.
本発明により、高純度で流動性がよく、気泡の発生を抑えた高均一性の成型体が得られ得る造粒シリカ粉体を提供することができる。 The present invention provides a granulated silica powder that is highly pure, has good fluidity, and can produce molded bodies with high uniformity and reduced bubble formation.
以下、本発明について詳細に説明するが、以下に記載する構成要件の説明は、本発明の実施形態の一例（代表例）であり、本発明はこれらの内容に限定されるものではなく、その要旨の範囲内で種々変形して実施することができる。 The present invention will be described in detail below. However, the following description of the components is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents, and can be practiced in various modifications within the scope of the gist.
本発明の一実施形態は、Ｄ５０粒径（メジアン径）が７５μｍ以上２００μｍ以下であり、安息角が２０度以上３５度以下であり、比表面積が０．３ｍ２／ｇ以上１０ｍ２／ｇ以下である造粒シリカ粉体であって、前記造粒シリカ粉体が、粒子径１０μｍ以下の粒子を１５％以上４０％以下含む凝集粒子である造粒シリカ粉体である。
従来使用されていた粒径１００μｍ～２００μｍの天然シリカ粉体や合成シリカ粉体は、その粒子形状は破砕状で流動性が悪い、粒子表面は溶融するが中心部は溶融不十分という粒子内での溶融粘度のムラが生じやすい、などの問題点を有していたところ、本実施形態では特定の性質を有する造粒シリカ粉体とすることで、上記問題を解決できるものである。
One embodiment of the present invention is a granulated silica powder having a D50 particle size (median size) of 75 μm or more and 200 μm or less, a repose angle of 20 degrees or more and 35 degrees or less, and a specific surface area of 0.3 m 2 /g or more and 10 m 2 /g or less, wherein the granulated silica powder is an agglomerated particle containing 15% to 40% particles with a particle size of 10 μm or less.
Conventionally used natural silica powders and synthetic silica powders having particle sizes of 100 μm to 200 μm have problems such as poor fluidity due to their crushed particle shape, and a tendency for uneven melt viscosity within the particle, in which the particle surface melts but the center is insufficiently melted. In this embodiment, however, the above problems can be solved by using a granulated silica powder having specific properties.
造粒シリカ粉体とすることで、流動性が良好な球状粒子を製造することが可能となり、また微粒子から造粒した造粒粒子であることから粒子の溶融の際に溶融ムラが少なくなる。 By making it into granulated silica powder, it is possible to produce spherical particles with good flowability, and because the granulated particles are made from fine particles, there is less uneven melting when the particles melt.
造粒シリカ粉体は、Ｄ５０粒径（メジアン径）が７５μｍ以上２００μｍ以下であり、１００μｍ以上であることが好ましく、１５０μｍ以下であることが好ましい。メジアン径は頻度の累積が５０％になる粒子径のことで、算出法の例として図２に示すように粒度分布曲線から作図で求めることができる。
造粒シリカ粉体のＤ５０粒径を上記範囲とすることで、流動性が高く、粉体の移送の定量性が良好となる。なお、造粒粒子のＤ５０粒径は、ふるい分け法やレーザー回折散乱法による粒度分布から算出することができ、篩などを用いた分級等により、Ｄ５０粒径を上記範囲に調整することができる。
The granulated silica powder has a D50 particle size (median diameter) of 75 μm to 200 μm, preferably 100 μm or more, and preferably 150 μm or less. The median diameter is the particle diameter at which the cumulative frequency is 50%, and can be calculated by plotting a particle size distribution curve as shown in FIG. 2, as an example of a calculation method.
By setting the D50 particle size of the granulated silica powder in the above range, the flowability is high and the quantitative transfer of the powder is good. The D50 particle size of the granulated particles can be calculated from the particle size distribution by the sieving method or the laser diffraction scattering method, and the D50 particle size can be adjusted to the above range by classification using a sieve or the like.
造粒シリカ粉体は、安息角が２０度以上３５度以下であり、２５度以上であることが好ましく、３０度以下であることが好ましい。
造粒シリカ粉体の安息角を上記範囲とすることで、流動性が高く、粉体の移送の定量性が良好となる。なお、安息角の測定方法は円筒回転法安息角測定装置（筒井理化学器械株式会社社製）を用いることができる。また、安息角の調整方法に関しては特に限定されないが、本明細書に記載した特定の粒度の原料を用い、噴霧造粒法で造粒することにより安息角を上記範囲内に調整することができる。
The granulated silica powder has an angle of repose of 20 degrees or more and 35 degrees or less, preferably 25 degrees or more and 30 degrees or less.
By setting the angle of repose of the granulated silica powder in the above range, the fluidity is high and the quantitative transfer of the powder is good. The angle of repose can be measured using a cylinder rotation method angle of repose measuring device (manufactured by Tsutsui Rikagaku Kikai Co., Ltd.). The method for adjusting the angle of repose is not particularly limited, but the angle of repose can be adjusted to within the above range by using a raw material of a specific particle size described in this specification and granulating it by a spray granulation method.
造粒シリカ粉体は、比表面積が０．３ｍ２／ｇ以上１０ｍ２／ｇ以下であり、０．５ｍ２／ｇ以上であることが好ましく、３ｍ２／ｇ以下であることが好ましい。
造粒シリカ粉体の比表面積を上記範囲とすることで、気泡の発生が抑えられた高均一性成型体が得られる粉体となる。なお、比表面積は、水銀ポロシメーターで測定することができ、以下に説明する粒径の原料を用いた噴霧造粒法で造粒シリカ粉体を造粒することにより比表面積を上記範囲内に調整することができる。
The granulated silica powder has a specific surface area of 0.3 m 2 /g or more and 10 m 2 /g or less, preferably 0.5 m 2 /g or more and 3 m 2 /g or less.
By setting the specific surface area of the granulated silica powder within the above range, the powder can be used to obtain a highly uniform molded product with reduced bubble generation. The specific surface area can be measured using a mercury porosimeter, and the specific surface area can be adjusted to within the above range by granulating the granulated silica powder using a spray granulation method using a raw material with a particle size as described below.
本実施形態の造粒シリカ粉体は、シリカ微粒子から造粒した凝集粒子であり、粒子径１０μｍ以下の粒子を１５％以上４０％以下含む凝集粒子であり、粒子径１０μｍ以下の粒子を２０％以上含むことが好ましく、３０％以下含むことが好ましい。
造粒シリカ粉体が、粒子径１０μｍ以下の粒子を上記範囲含むことで、微粒子が焼成時に適切にバインダーとなり、造粒した成型体の強度を向上させることができるとともに、造粒シリカ粉体の細孔径や細孔容積が適切な値となる。また、成型体に存在する泡の原因となるシラノール除去に関し、微粒子ほどシラノール除去速度が速いため造粒品のシラノール濃度低減に有利となる。
The granulated silica powder of this embodiment is an agglomerated particle granulated from silica fine particles, and is an agglomerated particle containing 15% or more and 40% or less of particles with a particle diameter of 10 μm or less, and preferably contains 20% or more, and preferably contains 30% or less, of particles with a particle diameter of 10 μm or less.
By containing particles with a particle diameter of 10 μm or less in the above range, the fine particles can appropriately function as a binder during firing, improving the strength of the granulated molded body, and the pore diameter and pore volume of the granulated silica powder become appropriate values. In addition, regarding the removal of silanol, which causes bubbles in the molded body, the finer the particles, the faster the silanol removal speed, which is advantageous for reducing the silanol concentration of the granulated product.
造粒シリカ粉体が、粒子径１０μｍ以下の粒子をどの程度の量を含むかは、造粒前であれば篩またはレーザー回折散乱法により求めることができ、造粒後であれば、その方法は限定されず、超音波などを用いて元のシリカが粉砕されない程度に造粒粉を解砕し、ＳＥＭ観察やレーザー回折散乱法粒度分布測定することにより測定できる。特に簡易に行う場合には、適宜粒子を埋め込み切断し、それをもとに１０μｍ以下の粒子の割合を推定してもよい。 The amount of particles with a particle size of 10 μm or less contained in the granulated silica powder can be determined by sieving or laser diffraction scattering method before granulation, and after granulation, the method is not limited, and it can be measured by crushing the granulated powder using ultrasound or the like to the extent that the original silica is not crushed, and then measuring the particle size distribution by SEM observation or laser diffraction scattering method. In a particularly simple case, the particles can be embedded and cut as appropriate, and the proportion of particles with a particle size of 10 μm or less can be estimated based on that.
本実施形態の造粒シリカ粉体は、シラノール濃度が２００ｐｐｍ以下であることが好ましく、１００ｐｐｍ以下であることがより好ましい。シラノール濃度を上記範囲とすることで、溶融時にシラノールから発生する水蒸気が少なくなり、ガラス成形体おいて水蒸気由来の泡の発生が抑制され、好ましい。シラノール濃度は、赤外分光光度計により測定できる。
また、造粒シリカ粉体は吸着水分量が１％以下であることが好ましく、０．１％以下であることがより好ましい。吸着水分量を上記範囲とすることで、シラノールと同じくガラス成形体おいて水蒸気由来の泡の発生が抑制され、好ましい。吸着水分量は、赤外線水分計により測定できる。
なお、シラノール濃度及び吸着水分量は、造粒シリカ粉体の製造において、焼成温度及び焼成時間を調整することで、所望の範囲とすることができる。
The granulated silica powder of this embodiment preferably has a silanol concentration of 200 ppm or less, more preferably 100 ppm or less. By setting the silanol concentration within the above range, the amount of water vapor generated from silanol during melting is reduced, and the generation of bubbles derived from water vapor in the glass molded body is suppressed, which is preferable. The silanol concentration can be measured by an infrared spectrophotometer.
In addition, the granulated silica powder preferably has an adsorbed moisture content of 1% or less, more preferably 0.1% or less. By setting the adsorbed moisture content within the above range, the generation of bubbles derived from water vapor in the glass molded body is suppressed, similar to silanol, which is preferable. The adsorbed moisture content can be measured by an infrared moisture meter.
The silanol concentration and the adsorbed water content can be adjusted to the desired range by adjusting the firing temperature and firing time in the production of the granulated silica powder.
造粒シリカ粉体は、Ｆｅ含有量が１ｐｐｍ以下であり、Ａｌ含有量が０．１ｐｐｍ以下であり、Ｔｉ含有量が０．０１ｐｐｍ以下であることが好ましい。このように金属含有量が低いことで、半導体治具や光ファイバーの製造に好適なシリカ粉となり好ましい。金属含有量は、フッ酸で造粒シリカ粉体を溶解後、誘導結合プラズマ質量分析法（ＩＣＰ－ＭＳ）により測定できる。 The granulated silica powder preferably has an Fe content of 1 ppm or less, an Al content of 0.1 ppm or less, and a Ti content of 0.01 ppm or less. This low metal content makes the silica powder suitable for manufacturing semiconductor jigs and optical fibers. The metal content can be measured by inductively coupled plasma mass spectrometry (ICP-MS) after dissolving the granulated silica powder with hydrofluoric acid.
また、造粒シリカ粉体は、平均細孔径が１μｍ以上１０μｍであることが好ましく、３
μｍ以上７μｍであることがより好ましい。また、平均細孔容積が０．１５ｃｃ／ｇ以上０．３５ｃｃ／ｇ以下であることが好ましく、０．２ｃｃ／ｇ以上０．３ｃｃ／ｇ以下であることがより好ましい。平均細孔径及び平均細孔容積が上記範囲にあることで気泡の発生が抑えられた高均一性成型体が得られる粉体となり、好ましい。平均細孔径及び平均細孔容積は、水銀ポロシメーターで測定することができる。
The granulated silica powder preferably has an average pore size of 1 μm or more and 10 μm or less.
It is more preferable that the average pore size is 0.15 cc/g or more and 0.35 cc/g or less, and more preferably 0.2 cc/g or more and 0.3 cc/g or less. The average pore size and the average pore volume are in the above ranges, which is preferable because they can produce a powder that is highly uniform and suppresses the generation of bubbles. The average pore size and the average pore volume can be measured by a mercury porosimeter.
造粒シリカ粉体は、その破壊強度が、取扱い上崩壊しない程度の強度が必要であるが、強度が高すぎると、溶融時のガス抜けが悪くなる。このため、０．５ＭＰａ以上１０ＭＰａ以下であることが好ましく、１ＭＰａ以上５ＭＰａ以下であることがより好ましい。破壊強度は微小圧縮試験機で測定することができる。 The crushing strength of the granulated silica powder must be strong enough that it does not crumble when handled, but if the strength is too high, gas escape during melting will be poor. For this reason, the crushing strength is preferably 0.5 MPa to 10 MPa, and more preferably 1 MPa to 5 MPa. Crushing strength can be measured using a microcompression tester.
本実施形態の造粒シリカ粉体の製造方法を以下に説明する。なお、造粒シリカ粉体の製造方法は、本発明の別の形態である。
本発明の別の形態は、粒子径１０μｍ以下の粒子を１５％以上４０％以下含み、ゾル・ゲル法により得られた原料シリカ粉体を準備する準備ステップ、原料シリカ粉体をスラリー化し、バインダーを加えて噴霧造粒する造粒ステップ、及び得られた造粒粒子を１０００℃以上１３００℃以下で焼成する焼成ステップ、を含む造粒シリカ粉体の製造方法である。
The method for producing the granulated silica powder of the present embodiment will be described below. The method for producing the granulated silica powder is another embodiment of the present invention.
Another aspect of the present invention is a method for producing a granulated silica powder, the method comprising the steps of: preparing a raw silica powder obtained by a sol-gel method, the raw silica powder containing 15% to 40% particles with a particle diameter of 10 μm or less; a granulation step of slurriing the raw silica powder, adding a binder, and spray granulating the slurry; and a firing step of firing the obtained granulated particles at 1000° C. to 1300° C.
＜準備ステップ＞
準備ステップは、粒子径１０μｍ以下の粒子を１５％以上４０％以下含み、ゾル・ゲル法により得られた原料シリカ粉体を準備するステップである。ゾル・ゲル法により製造されたシリカ粉体は、高純度でかつ適切な粒子径となりやすい。そのため、金属含有量が低く、半導体向け原料として好ましい。また、後述の造粒ステップにおけるスラリー調製において、分散性に優れる。
<Preparation steps>
The preparation step is a step of preparing raw silica powder obtained by the sol-gel method, containing 15% to 40% particles with a particle diameter of 10 μm or less. The silica powder produced by the sol-gel method is likely to have high purity and an appropriate particle diameter. Therefore, it has a low metal content and is preferable as a raw material for semiconductors. In addition, it has excellent dispersibility in the slurry preparation in the granulation step described later.
更に、粒子径１０μｍ以下の微粒子を上記割合で含むことで、微粒子が適切にバインダーとなり、造粒シリカ粉体の細孔径や細孔容積が適切な値となる。また、成型体に存在する泡の原因となるシラノール除去を除去することができることから、造粒した成型体の強度を向上させることができる。
ゾル・ゲル法は、公知の方法を用いることができ、純度の面から、テトラメトキシシランやテトラエトキシシランをＳｉ源として、加水分解することが好ましい。
Furthermore, by including the fine particles having a particle diameter of 10 μm or less in the above ratio, the fine particles act as a binder appropriately, and the pore diameter and pore volume of the granulated silica powder become appropriate values. Also, since it is possible to remove silanol that causes bubbles in the molded body, the strength of the granulated molded body can be improved.
The sol-gel method can be carried out by a known method, and from the standpoint of purity, it is preferable to carry out hydrolysis using tetramethoxysilane or tetraethoxysilane as the Si source.
＜造粒ステップ＞
造粒ステップは、原料シリカをスラリー化し、バインダーを加えて噴霧造粒するステップである。造粒により、得られる造粒シリカ粉体を球形化でき、またこの方法を採用することでコンタミを抑制することができる。
<Granulation step>
The granulation step is a step in which the raw silica is slurried, a binder is added, and the mixture is sprayed and granulated. Granulation makes it possible to make the granulated silica powder spherical, and by adopting this method, contamination can be suppressed.
スラリー化する際の溶媒は通常水であるが、造粒の際の分散媒として使用できるものであれば、これに限られない。スラリーの粘度は特に限定されない。また、スラリー調製の際にバインダーを添加してもよい。バインダーは最終的な造粒シリカ粉体に残留しない物質が適しており、造粒後の焼成により燃焼分解、除去できる有機バインダーがよい。有機バインダーとしては、天然ポリマー、半合成ポリマー、合成ポリマーが挙げられるが、純度の観点から、合成ポリマーのアクリルポリマー、ポリアクリルアミド、ポリビニルピロリドン、ポリビニルアルコールなどが好ましく、なかでもポリビニルピロリドンが好ましい。バインダーを用いる際には、原料シリカ１００重量部に対し通常３重量部以上１０重量部の割合で用いる。
噴霧は公知のスプレー（噴霧器）を用いればよく、特に限定されない。
造粒ステップで造粒した造粒シリカは、乾燥させてもよい。
The solvent used for slurrying is usually water, but is not limited to this as long as it can be used as a dispersion medium during granulation. The viscosity of the slurry is not particularly limited. A binder may also be added during slurry preparation. The binder is preferably a substance that does not remain in the final granulated silica powder, and is preferably an organic binder that can be burned, decomposed, and removed by firing after granulation. Examples of organic binders include natural polymers, semi-synthetic polymers, and synthetic polymers, but from the viewpoint of purity, synthetic polymers such as acrylic polymers, polyacrylamide, polyvinylpyrrolidone, and polyvinyl alcohol are preferred, and polyvinylpyrrolidone is particularly preferred. When using a binder, it is usually used at a ratio of 3 parts by weight to 10 parts by weight per 100 parts by weight of raw silica.
The spraying may be performed using a known spray (sprayer) without any particular limitation.
The granulated silica produced in the granulation step may be dried.
＜焼成ステップ＞
焼成ステップは、得られた造粒粒子を１０００℃以上１３００℃以下で焼成するステップである。焼成温度が低いと造粒品の強度が低く、高温すぎると造粒粉どうしの固着が起こり好ましくない。焼成温度は１１００℃以上が好ましく、１２５０℃以下が好ましい。焼成時間は強度に影響があり、焼成時間は通常１０時間以上１００時間以下であり、３０時間以上が好ましく６０時間以下が好ましい。
焼成の際の雰囲気は特に限定さないが、乾燥空気雰囲気化で行うことが好ましい。乾燥空気としては露点－４０℃以下であることが好ましい。
<Firing step>
The firing step is a step in which the obtained granulated particles are fired at 1000°C or more and 1300°C or less. If the firing temperature is low, the strength of the granulated product is low, and if the firing temperature is too high, the granulated powders will stick to each other, which is not preferable. The firing temperature is preferably 1100°C or more and 1250°C or less. The firing time affects the strength, and is usually 10 hours or more and 100 hours or less, preferably 30 hours or more and 60 hours or less.
The atmosphere during firing is not particularly limited, but firing is preferably performed in a dry air atmosphere, preferably with a dew point of −40° C. or less.
上記造粒シリカ粉体は、ベルヌイ法やプラズマ溶射法など既知の方法により溶融されて、ガラス成型体となる。また、この際の溶融条件等も特に限定されるものではない。 The granulated silica powder is melted by a known method such as the Verneuil process or plasma spraying to form a glass molded body. The melting conditions are not particularly limited.
以下、実施例により本発明をより詳細に説明するが、本発明の範囲は、以下の実施例により限定されるものではない。 The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to the following examples.
＜実施例＞
（１）原料シリカ粉体の調製
リボン型攪拌翼を有するジャケット付き横型円筒反応機に、ＴＭＯＳ（テトラメトキシシラン）とその６倍モル比の水を加えて、ジャケットに５０℃の温水を通して、ＴＭＯＳの加水分解を行い、生成したウェットゲルを抜き出した。抜き出したウェットゲルを孔径１ｍｍの高速回転ミル型粉砕機（Ｑｕａｄｒｏ社製、Ｃｏｍｉｌ）を用いて粉砕したのち、粉砕物を１５０℃で乾燥して、乾燥シリカゲル粉体を得た。この粉体を目開き１２５μｍの篩で分級し、その篩下の粉体をさらに目開きの細かい篩を使って分級し、原料シリカ粉体とした。原料シリカ粉体はＡ、Ｂの２種類調製し、その粉体の粒度分布を図１Ａ、図１Ｂに示し、粒径１０μｍ以下の粒子の割合はＡは２５％、Ｂは３５％であった。
<Example>
(1) Preparation of raw silica powder TMOS (tetramethoxysilane) and 6 times the molar ratio of water were added to a jacketed horizontal cylindrical reactor having a ribbon-type stirring blade, and hot water at 50 ° C. was passed through the jacket to hydrolyze TMOS, and the resulting wet gel was extracted. The extracted wet gel was pulverized using a high-speed rotary mill-type grinder (Quadro, Comil) with a hole diameter of 1 mm, and the pulverized material was dried at 150 ° C. to obtain a dried silica gel powder. This powder was classified using a sieve with a mesh size of 125 μm, and the powder under the sieve was further classified using a sieve with a finer mesh size to obtain raw silica powder. Two types of raw silica powder, A and B, were prepared, and the particle size distribution of the powder is shown in Figure 1A and Figure 1B, and the proportion of particles with a particle size of 10 μm or less was 25% for A and 35% for B.
（２）造粒
上記（１）で調製した原料シリカ粉体を水に分散させ、原料シリカ３０重量％のスラリーとした。さらに造粒バインダーとして、ポリビニルピロリドンを原料シリカ粉体１００重量部に対し５重量部添加した。このスラリーに対し、スプレードライヤ（プリス社製）を使って、乾燥ガス温度１５０℃で噴霧乾燥して造粒粒子を得た。この造粒粒子を空気（露点－６８℃）雰囲気中で１２２０℃、４０時間加熱し、造粒シリカ粉体を得た。得られた造粒シリカ粉体の物性を以下のように測定した。
(2) Granulation The raw silica powder prepared in (1) above was dispersed in water to prepare a slurry containing 30% by weight of raw silica. Furthermore, 5 parts by weight of polyvinylpyrrolidone was added as a granulation binder to 100 parts by weight of the raw silica powder. This slurry was spray-dried at a drying gas temperature of 150°C using a spray dryer (manufactured by PRIS) to obtain granulated particles. The granulated particles were heated at 1220°C for 40 hours in an air atmosphere (dew point -68°C) to obtain granulated silica powder. The physical properties of the obtained granulated silica powder were measured as follows.
＜粒度分布＞
得られた造粒シリカ粉体の粒度を、篩分けで測定した結果を図２に示す。原料シリカ粉体Ａ、Ｂから製造した造粒シリカ粉体Ａ、Ｂの粒度は一致した。なお、Ｄ５０粒径（メジアン径）は図中に示した通り１３０μｍであった。
このＤ５０粒径（メジアン径）は、ステンレス製のＪＩＳ標準ふるいを用い、目開き４５、７５、１０６、１２５、１５０、２１２、２５０μｍのふるいを順に使って、その通過重量を測定し、通過した累積重量をエクセルによりグラフ化し、平滑線を引いて、これを用いて累積％が５０％となる点を求めることにより、求めた。
<Particle size distribution>
The particle size of the obtained granulated silica powder was measured by sieving, and the results are shown in Figure 2. The particle sizes of granulated silica powders A and B produced from raw silica powders A and B were the same. The D50 particle size (median diameter) was 130 μm, as shown in the figure.
The D50 particle size (median diameter) was determined by measuring the weight of particles passing through stainless steel JIS standard sieves having mesh sizes of 45, 75, 106, 125, 150, 212, and 250 μm in that order, graphing the cumulative weight of particles that passed through them in Excel, drawing a smooth line, and using this to determine the point where the cumulative percentage is 50%.
＜ＳＥＭ画像＞
図３に、得られた造粒シリカ粉体のＳＥＭ画像を示す。粒子は球状（Ａ）で、拡大すると（Ｂ）大粒子の隙間に小粒子が存在することが分かる。
＜安息角＞
得られた造粒シリカ粉体の安息角を、円筒回転法安息角測定装置（筒井理化学器械株式会社社製）で測定した結果、造粒シリカ粉体Ａ、Ｂとも２８度であった。
<SEM image>
An SEM image of the resulting granulated silica powder is shown in Figure 3. The particles are spherical (A), and when magnified (B), it can be seen that small particles are present between the gaps between the larger particles.
<Angle of repose>
The repose angles of the obtained granulated silica powders were measured using a cylinder rotation method repose angle measuring device (manufactured by Tsutsui Rikagaku Kikai Co., Ltd.) and were both 28 degrees for granulated silica powders A and B.
＜比表面積＞
得られた造粒シリカ粉体の比表面積を、水銀ポロシメーターで測定した結果、比表面積はＡは０．６８ｍ２／ｇ、Ｂは２．２ｍ２／ｇ、細孔容積はＡは０．２５ｃｃ／ｇ、Ｂは０．２９あった。細孔径はＡ、Ｂとも３．７μｍであった。
＜硬度＞
得られた造粒シリカ粉体の破壊強度の測定結果は、Ａ、Ｂとも１．４ＭＰａであり、通常取扱いに十分な硬さを有していた。
＜不純物濃度＞
ＩＣＰ－ＭＳにより、Ｆｅ、Ａｌ、Ｔｉの濃度を測定した。その結果、造粒シリカ粉体Ａの各濃度はＦｅ、Ａｌ、Ｔｉの順に０．６８、０．０４、＜０．０１ｐｐｍ、同様に造粒シリカ粉体Ｂは０．５５、０．０７、＜０．０１ｐｐｍであった。
<Specific surface area>
The specific surface areas of the resulting granulated silica powders were measured with a mercury porosimeter, and the specific surface areas were 0.68 m 2 /g for A and 2.2 m 2 /g for B, and the pore volumes were 0.25 cc/g for A and 0.29 for B. The pore diameters were both 3.7 μm.
<Hardness>
The breaking strength of the obtained granulated silica powder was measured and found to be 1.4 MPa for both A and B, which was sufficiently hard for normal handling.
<Impurity concentration>
The concentrations of Fe, Al, and Ti were measured by ICP-MS. As a result, the concentrations of Fe, Al, and Ti in granulated silica powder A were 0.68, 0.04, and <0.01 ppm, respectively, and those in granulated silica powder B were 0.55, 0.07, and <0.01 ppm, respectively.
（３）成型体の製造
図４に模式図を示すベルヌイ法（酸水素炎溶融法）装置で、上記得られた造粒シリカ粉体を用いて、ガラスインゴットを作製した。溶融したインゴット（親指大）写真を図５に示す。造粒シリカ粉体Ａ、Ｂとも数個の気泡が発生したが、十分許容範囲であった。
(3) Manufacturing of molded body A glass ingot was manufactured using the granulated silica powder obtained above in a Verneuil process (oxyhydrogen flame fusion process) apparatus as shown in the schematic diagram of Figure 4. A photograph of the molten ingot (thumb-sized) is shown in Figure 5. Although several bubbles were generated in both granulated silica powders A and B, they were within the acceptable range.
＜比較例＞
実施例の（１）の１２５μｍ篩上のシリカゲル粉体を実施例と同じく１２２０℃で４０時間焼成して、さらに２１２μｍ篩でふるい、その篩下シリカ粉体を得た。その粉体のＤ５０は実施例の造粒粉体と一致した。また、その比表面積は０．１ｍ２／ｇ未満、細孔容積は０．０１ｃｃ／ｇ未満であった。ＳＥＭ画像を図６に示すが、粒子は破砕状で、造粒粒子の図３のような微粒子凝集構造は見当たらなかった。
このシリカ粉体の安息角を測定したところ３７度であった。
また実施例と同じベルヌイ法装置を用いて、ガラスインゴットを作製しようとしたが、粉体溜り以降の配管で閉塞が起こり、スムーズに粉体が流れなかった。
Comparative Example
The silica gel powder on the 125 μm sieve in Example (1) was calcined at 1220° C. for 40 hours as in Example, and then sieved through a 212 μm sieve to obtain an undersized silica powder. The D50 of the powder was consistent with that of the granulated powder in Example. The specific surface area was less than 0.1 m 2 /g, and the pore volume was less than 0.01 cc/g. The SEM image is shown in FIG. 6, but the particles were crushed, and no fine particle aggregate structure like that of the granulated particles in FIG. 3 was observed.
The angle of repose of this silica powder was measured and found to be 37 degrees.
An attempt was made to produce a glass ingot using the same Verneuil process apparatus as in the embodiment, but blockage occurred in the piping downstream of the powder reservoir, preventing the powder from flowing smoothly.
１ 粉体ホッパー
２ 粉体溜まり
３ バイブレーター
４ ノズルクッション
５ 石英ノズル
６ 耐熱煉瓦
７ インゴット
８ 支持回転棒
９ モーター
１０ 昇降ステージ
1
Claims (6)
前記造粒シリカ粉体が、粒子径１０μｍ以下のシリカ微粒子を１５重量％以上４０重量％以下含む凝集粒子である造粒シリカ粉体。 A granulated silica powder having a D50 particle size (median diameter) of 75 μm or more and 200 μm or less, an angle of repose of 20 degrees or more and 35 degrees or less, and a specific surface area of 0.3 m 2 /g or more and 10 m 2 /g or less,
The granulated silica powder is an agglomerated particle containing 15% by weight or more and 40% by weight or less of silica fine particles having a particle diameter of 10 μm or less.
原料シリカをスラリー化し、バインダーを加えて噴霧造粒する造粒ステップ、及び
得られた造粒粒子を１０００℃以上１３００℃以下で焼成する焼成ステップ、を含む請求項１乃至４のいずれか１項に記載の造粒シリカ粉体の製造方法。 A preparation step of preparing raw material silica obtained by a sol-gel method, the raw material silica containing 15% by weight or more and 40% by weight or less of silica fine particles having a particle diameter of 10 μm or less;
The method for producing the granulated silica powder according to any one of claims 1 to 4, comprising: a granulation step of slurried raw silica, adding a binder, and spray granulating the slurry; and a calcination step of calcining the resulting granulated particles at 1000°C or higher and 1300°C or lower.
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| JP2019503961A (en) | 2015-12-18 | 2019-02-14 | ヘレウス クワルツグラス ゲーエムベーハー ウント コンパニー カーゲー | Ammonia treatment of silicon dioxide powder in the preparation of quartz glass |
| US20190077691A1 (en) | 2015-12-18 | 2019-03-14 | Heraeus Quarzglas Gmbh & Co. Kg | Spray granulation of silicon dioxide in the preparation of quartz glass |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2019503961A (en) | 2015-12-18 | 2019-02-14 | ヘレウス クワルツグラス ゲーエムベーハー ウント コンパニー カーゲー | Ammonia treatment of silicon dioxide powder in the preparation of quartz glass |
| US20190077691A1 (en) | 2015-12-18 | 2019-03-14 | Heraeus Quarzglas Gmbh & Co. Kg | Spray granulation of silicon dioxide in the preparation of quartz glass |
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