JP2017214288A - Titanium oxide particle and production method thereof - Google Patents
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- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims abstract description 211
- 239000002245 particle Substances 0.000 title claims abstract description 207
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 title claims abstract description 196
- 238000004519 manufacturing process Methods 0.000 title description 24
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 25
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 12
- 238000004438 BET method Methods 0.000 claims abstract description 5
- 238000001179 sorption measurement Methods 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 45
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 claims description 20
- 239000002002 slurry Substances 0.000 claims description 14
- 239000003989 dielectric material Substances 0.000 claims description 11
- 229910001961 silver nitrate Inorganic materials 0.000 claims description 10
- 238000004458 analytical method Methods 0.000 claims description 8
- 239000006185 dispersion Substances 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 6
- 238000003918 potentiometric titration Methods 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 5
- 229910052717 sulfur Inorganic materials 0.000 claims description 5
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 229910052758 niobium Inorganic materials 0.000 claims description 4
- 229910052726 zirconium Inorganic materials 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 229910052708 sodium Inorganic materials 0.000 claims description 3
- 238000007561 laser diffraction method Methods 0.000 abstract 1
- 238000000790 scattering method Methods 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 89
- 239000000460 chlorine Substances 0.000 description 74
- 238000006243 chemical reaction Methods 0.000 description 52
- 239000011261 inert gas Substances 0.000 description 44
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 39
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 28
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 19
- 239000001301 oxygen Substances 0.000 description 19
- 229910052760 oxygen Inorganic materials 0.000 description 19
- 238000009826 distribution Methods 0.000 description 17
- 238000010438 heat treatment Methods 0.000 description 15
- 239000002994 raw material Substances 0.000 description 15
- 238000005259 measurement Methods 0.000 description 12
- 239000000243 solution Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 11
- 238000006298 dechlorination reaction Methods 0.000 description 11
- 239000012535 impurity Substances 0.000 description 9
- 238000001816 cooling Methods 0.000 description 8
- 230000000704 physical effect Effects 0.000 description 7
- 230000002776 aggregation Effects 0.000 description 6
- 230000001186 cumulative effect Effects 0.000 description 6
- 229910010413 TiO 2 Inorganic materials 0.000 description 5
- 238000004220 aggregation Methods 0.000 description 5
- 239000013078 crystal Substances 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 239000010419 fine particle Substances 0.000 description 5
- 239000012071 phase Substances 0.000 description 5
- 239000011941 photocatalyst Substances 0.000 description 5
- 238000005245 sintering Methods 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 4
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- 229910052801 chlorine Inorganic materials 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 230000004907 flux Effects 0.000 description 4
- 239000007791 liquid phase Substances 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 4
- -1 solar cells Substances 0.000 description 4
- 239000012808 vapor phase Substances 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 3
- 238000000149 argon plasma sintering Methods 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 239000002826 coolant Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000000382 dechlorinating effect Effects 0.000 description 2
- 238000011033 desalting Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910052736 halogen Inorganic materials 0.000 description 2
- 229910052734 helium Inorganic materials 0.000 description 2
- 239000001307 helium Substances 0.000 description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 2
- 238000000265 homogenisation Methods 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000011002 quantification Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 238000004062 sedimentation Methods 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- GCLGEJMYGQKIIW-UHFFFAOYSA-H sodium hexametaphosphate Chemical compound [Na]OP1(=O)OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])O1 GCLGEJMYGQKIIW-UHFFFAOYSA-H 0.000 description 2
- 235000019982 sodium hexametaphosphate Nutrition 0.000 description 2
- 239000001577 tetrasodium phosphonato phosphate Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 235000010724 Wisteria floribunda Nutrition 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000003985 ceramic capacitor Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000001095 inductively coupled plasma mass spectrometry Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000000386 microscopy Methods 0.000 description 1
- DCKVFVYPWDKYDN-UHFFFAOYSA-L oxygen(2-);titanium(4+);sulfate Chemical compound [O-2].[Ti+4].[O-]S([O-])(=O)=O DCKVFVYPWDKYDN-UHFFFAOYSA-L 0.000 description 1
- 230000001699 photocatalysis Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000000634 powder X-ray diffraction Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 239000004945 silicone rubber Substances 0.000 description 1
- 238000003746 solid phase reaction Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 229910000348 titanium sulfate Inorganic materials 0.000 description 1
- 239000011882 ultra-fine particle Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 238000004876 x-ray fluorescence Methods 0.000 description 1
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
Description
本発明は、酸化チタン粒子及びその製造方法、並びに酸化チタン粒子を含むスラリー、分散体、組成物及び誘電体原料に関する。 The present invention relates to titanium oxide particles and a method for producing the same, and a slurry, a dispersion, a composition, and a dielectric material containing the titanium oxide particles.
酸化チタンの工業的応用分野は極めて広く、化粧品、紫外線遮蔽材、シリコーンゴムヘの添加剤を代表とし、近年では、光触媒、太陽電池、誘電体原料、Ｌｉイオン電池用電極材原料など用途は多岐に亘っている。なお、「酸化チタン」は、日本工業規格（ＪＩＳ）には二酸化チタンと記載されているが、一般名として酸化チタンが広く使用されているので本明細書では酸化チタンと略称する。
最近、酸化チタンは特に高性能の誘電体原料、例えばＢａＴｉＯ３の原料として注目されている。ＢａＴｉＯ３は加熱下で次の反応によって得られる。
ＢａＣＯ３＋ＴｉＯ２→ＢａＴｉＯ３＋ＣＯ２
上記の反応は固相反応であり、その際先ず高温でＢａＣＯ３が分解してＢａＯが生成し、ＢａＯがＴｉＯ２粒子中を拡散固溶してＢａＴｉＯ３になると言われている。従ってＢａＴｉＯ３粒子の大きさはＴｉＯ２粒子の大きさに支配されることになる。近年では、積層セラミックコンデンサーの小型化に伴って、誘電層の薄層化が課題となっており、そのためにはＢａＴｉＯ３粒子の微粒化及び均一化が不可欠となっている。従って、当該均一化のためには、ＢａＴｉＯ３の原料であるＴｉＯ２の微粒化及び均一化が必要である。
Titanium oxide has a very wide range of industrial applications, typically cosmetics, UV shielding materials, and additives to silicone rubber. In recent years, it has been used in a wide variety of applications such as photocatalysts, solar cells, dielectric materials, and Li-ion battery electrode materials. It is over. “Titanium oxide” is described as titanium dioxide in the Japanese Industrial Standards (JIS), but titanium oxide is widely used as a general name, and is therefore abbreviated as titanium oxide in this specification.
Recently, titanium oxide has attracted attention as a raw material for particularly high-performance dielectric materials such as BaTiO 3 . BaTiO 3 is obtained by the following reaction under heating.
BaCO 3 + TiO 2 → BaTiO 3 + CO 2
The above reaction is a solid-phase reaction, and at that time, BaCO 3 is first decomposed at a high temperature to generate BaO, and BaO is said to be diffused and dissolved in TiO 2 particles to become BaTiO 3 . Accordingly, the size of the BaTiO 3 particles is governed by the size of the TiO 2 particles. In recent years, with the miniaturization of multilayer ceramic capacitors, it has become a challenge to reduce the thickness of the dielectric layer, and for that purpose, atomization and homogenization of BaTiO 3 particles are indispensable. Therefore, for the homogenization, it is necessary to atomize and homogenize TiO 2 which is a raw material of BaTiO 3 .
酸化チタンの製造法は、大別して四塩化チタンや硫酸チタンを加水分解する液相法と、四塩化チタンを酸素又は水蒸気と高温で反応させる気相法がある。 The production methods of titanium oxide are roughly classified into a liquid phase method in which titanium tetrachloride and titanium sulfate are hydrolyzed and a gas phase method in which titanium tetrachloride is reacted with oxygen or water vapor at a high temperature.
液相法は、比較的温和な条件下で酸化チタンを製造することができるという利点があるが、酸化チタンがゾル又はスラリーの状態で得られるため、この状態で使用する場合、用途が限定されるという問題がある。
また、当該ゾル又はスラリーを酸化チタン粒子として使用するためには乾燥させる必要があり、乾燥後は一般に凝集が激しくなる。このように凝集の激しい酸化チタン粒子は、粒径が不均一になるという問題がある。また、当該酸化チタン粒子を溶媒に分散させたときの分散性が悪いという問題もある。分散性が悪いと、上記のＢａＴｉＯ３の生成のために原料を混合する際に、酸化チタン粒子と他の原料とが十分に混合せず、原料成分に偏在が生じ、反応時に不均一成長を引き起こして、強度低下等の性能低下、品質のばらつき等が生じる。また、分散性を高めるために酸化チタンを解砕・粉砕する場合、粉砕等の処理に由来する摩耗物の混入や粒度分布の不均一化等の問題を引き起こすことがある。
The liquid phase method has an advantage that titanium oxide can be produced under relatively mild conditions. However, since titanium oxide is obtained in a sol or slurry state, its use is limited when used in this state. There is a problem that.
Moreover, in order to use the said sol or slurry as a titanium oxide particle, it is necessary to dry, and generally aggregation becomes intense after drying. As described above, the titanium oxide particles that are intensively aggregated have a problem of non-uniform particle sizes. There is also a problem that the dispersibility is poor when the titanium oxide particles are dispersed in a solvent. If the dispersibility is poor, when the raw materials are mixed for the production of BaTiO 3 described above, the titanium oxide particles and other raw materials are not sufficiently mixed, resulting in uneven distribution of the raw material components and uneven growth during the reaction. As a result, performance degradation such as strength reduction, quality variation, and the like occur. In addition, when titanium oxide is pulverized and pulverized in order to improve dispersibility, problems such as contamination of wear due to processing such as pulverization and non-uniform particle size distribution may occur.
一方、気相法によると、酸化チタンは粉末として得られ、また気相法では溶媒を使用しないため、液相法で挙げた問題が生じることは少ない。しかしながら、気相法によると、原料に四塩化チタンを使うため、得られる酸化チタン粒子にＣｌが含まれてしまうという問題がある。
例えば、このＣｌを含む酸化チタン粒子をＢａＴｉＯ３の原料として用いる場合、このＣｌを含む酸化チタン粒子とＢａＣＯ３とを混合して加熱する際にＢａＯが生成し、ＣｌがこのＢａＯと反応してＢａＣｌ２が生成する。生成したＢａＣｌ２は溶融してフラックスの作用をし、ＴｉＯ２粒子やＢａＴｉＯ３粒子の凝集を引き起す。また溶融したフラックスは局在化し易く、その局在化した部分では凝集が多くなり、他の部分との間で品質にバラツキが生ずる。粒子が凝集するとＢａＴｉＯ３粒子の結晶が成長して異常粒子となり、ＢａＴｉＯ３の誘電特性を低下させることになる。上記の問題は、酸化チタン中のＣｌの存在状態にかかわらず起きる可能性があるため、粒子表面及び粒子内部のどちらのＣｌも減らす必要がある。
On the other hand, according to the gas phase method, titanium oxide is obtained as a powder, and since the solvent is not used in the gas phase method, the problems mentioned in the liquid phase method are rare. However, according to the vapor phase method, since titanium tetrachloride is used as a raw material, there is a problem that Cl is contained in the obtained titanium oxide particles.
For example, when titanium oxide particles containing Cl are used as a raw material for BaTiO 3 , BaO is generated when the titanium oxide particles containing Cl and BaCO 3 are mixed and heated, and Cl reacts with the BaO. BaCl 2 is formed. The generated BaCl 2 melts and acts as a flux, causing aggregation of TiO 2 particles and BaTiO 3 particles. Also, the melted flux is likely to be localized, and the localized portion is more agglomerated, resulting in variations in quality with other portions. When the particles are aggregated, crystals of BaTiO 3 particles grow to become abnormal particles, and the dielectric properties of BaTiO 3 are reduced. Since the above problem may occur regardless of the presence state of Cl in titanium oxide, it is necessary to reduce both Cl on the particle surface and inside the particle.
特許文献１には、Ｃｌ等のハロゲン含有量の少ない酸化チタン粒子を気相法により得ることを目的として、ハロゲン化チタンガスを気相中で加水分解又は酸化反応させて得られる粗酸化チタン粒子を、アルコール及び水蒸気を含有する混合ガスに接触させることを特徴とする低ハロゲン酸化チタン粒子の製造方法が記載されている。 Patent Document 1 discloses crude titanium oxide particles obtained by hydrolyzing or oxidizing a titanium halide gas in a gas phase for the purpose of obtaining titanium oxide particles having a low halogen content such as Cl by a gas phase method. Describes a method for producing low-halogen titanium oxide particles, which is characterized by contacting the mixture with a mixed gas containing alcohol and water vapor.
上記のとおり、Ｃｌ含有量が少なく、均一性及び分散性に優れる酸化チタン粒子が望まれている。しかしながら、液相法により得られる酸化チタン粒子は均一性及び分散性に劣る。また気相法により得られる酸化チタン粒子は、Ｃｌ含有量が多い。なお、特許文献１により得られる酸化チタン粒子も、Ｃｌ含有量が十分に低減されない。
本発明は、上記の問題点を解決すべくなされたものであり、本発明の課題は、Ｃｌ含有量が低く、かつ均一性及び分散性に優れる酸化チタン粒子及びその製造方法、並びに当該酸化チタンを含むスラリー、分散体、組成物及び誘電体原料を提供することにある。
As described above, titanium oxide particles having a low Cl content and excellent uniformity and dispersibility are desired. However, titanium oxide particles obtained by the liquid phase method are inferior in uniformity and dispersibility. Further, titanium oxide particles obtained by a vapor phase method have a high Cl content. In addition, the titanium oxide particles obtained according to Patent Document 1 are also not sufficiently reduced in Cl content.
The present invention has been made to solve the above-mentioned problems. An object of the present invention is to provide titanium oxide particles having a low Cl content and excellent uniformity and dispersibility, a method for producing the same, and the titanium oxide. Providing a slurry, a dispersion, a composition, and a dielectric material.
本発明者らは、上記課題に鑑み鋭意研究した結果、四塩化チタン及び不活性ガスを特定量含有するガス及び特定の酸化性ガスを含有するガスを反応させて粗酸化チタン粒子を製造する第１工程と、該粉末を乾式脱塩法で脱塩する第２工程と、を経ることにより、Ｃｌ含有量が少なく、かつ均一性及び分散性に優れた酸化チタン粒子を製造し得ることを見出した。 As a result of diligent research in view of the above problems, the inventors of the present invention produce crude titanium oxide particles by reacting a gas containing a specific amount of titanium tetrachloride and an inert gas and a gas containing a specific oxidizing gas. It has been found that titanium oxide particles having low Cl content and excellent uniformity and dispersibility can be produced by passing through one step and a second step of desalting the powder by a dry desalting method. It was.
すなわち、本発明は、以下の［１］〜［１３］を提供するものである。
［１］四塩化チタン及び不活性ガスを含有するガスＧ１と、酸素及び水蒸気の少なくとも１種並びに不活性ガスを含有するガスＧ２とを、反応管に導入して反応させ、粗酸化チタン粒子を製造する第１工程と、該粗酸化チタン粒子を乾式脱塩素法で脱塩素する第２工程と、を有し、第１工程の反応管に導入する不活性ガスの総量（ガスＧ１とガスＧ２中の不活性ガスの合計量）が、四塩化チタン１モルに対して１モル以上５０モル以下であり、ガスＧ２中の不活性ガス量が、ガスＧ１中の不活性ガス１モルに対し、５モル以上である、酸化チタン粒子の製造方法。
［２］第１工程において、ガスＧ１及びガスＧ２を、温度が９００℃以上１，２００℃未満である反応管内に導入して反応させる、［１］に記載の酸化チタン粒子の製造方法。
［３］第１工程において、四塩化チタン１モルに対し、ガスＧ２中における酸素及び水蒸気の総量が１モル以上５０モル以下となるように、ガスＧ１及びガスＧ２を反応管に導入する、［１］又は［２］に記載の酸化チタン粒子の製造方法。
［４］第１工程において、四塩化チタン１モルに対し、ガスＧ１中における不活性ガス量が３モル未満となるように、ガスＧ１及びガスＧ２を反応管に導入する、［１］〜［３］のいずれかに記載の酸化チタン粒子の製造方法。
［５］全Ｃｌ含有量ａが２００質量ｐｐｍ以下であり、レーザー回折・散乱分析法により測定したＤ９０／Ｄ５０をＸとし、窒素吸着によるＢＥＴ法により測定したＢＥＴ比表面積をＹ（ｍ２／ｇ）とした場合、Ｘ／Ｙが０．０６０以下である酸化チタン粒子。
［６］酸化チタン粒子中における全Ｃｌ含有量ａ（質量ｐｐｍ）から、硝酸銀電位差滴定法により測定した酸化チタン粒子の表面Ｃｌ含有量ｂ（質量ｐｐｍ）を差し引いて得られる、酸化チタン粒子の内部Ｃｌ含有量ｃが、２００質量ｐｐｍ以下である、請求項５に記載の酸化チタン粒子。
［７］ＢＥＴ比表面積Ｙが２０〜２００ｍ２／ｇである、［５］又は［６］に記載の酸化チタン粒子。
［８］酸化チタンの含有量が９９．９質量％以上である［５］〜［７］のいずれかに記載の酸化チタン粒子。
［９］Ｎａ，Ａｌ，Ｓ，Ｆｅ，Ｎｉ，Ｃｒ，Ｎｂ及びＺｒの含有量がそれぞれ１０質量ｐｐｍ以下、Ｓｉ及びＣの含有量がそれぞれ１００質量ｐｐｍ以下、である［５］〜［８］のいずれかに記載の酸化チタン粒子。
［１０］［５］〜［９］のいずれかに記載の酸化チタン粒子を含むスラリー。
［１１］［５］〜［９］のいずれかに記載の酸化チタン粒子を含む分散体。
［１２］［５］〜［９］のいずれかに記載の酸化チタン粒子を含む組成物。
［１３］［５］〜［９］のいずれかに記載の酸化チタン粒子から得られた誘電体原料。
That is, the present invention provides the following [1] to [13].
[1] A gas G1 containing titanium tetrachloride and an inert gas, and a gas G2 containing at least one of oxygen and water vapor and an inert gas are introduced into a reaction tube and reacted to produce crude titanium oxide particles. A total amount of inert gas (gas G1 and gas G2) to be introduced into the reaction tube of the first step, and a first step of producing and a second step of dechlorinating the crude titanium oxide particles by dry dechlorination. The total amount of the inert gas in the gas G1 is 1 mol or more and 50 mol or less with respect to 1 mol of titanium tetrachloride, and the amount of the inert gas in the gas G2 is 1 mol of the inert gas in the gas G1. The manufacturing method of the titanium oxide particle which is 5 mol or more.
[2] The method for producing titanium oxide particles according to [1], wherein in the first step, the gas G1 and the gas G2 are introduced into a reaction tube having a temperature of 900 ° C. or higher and lower than 1,200 ° C. and reacted.
[3] In the first step, the gas G1 and the gas G2 are introduced into the reaction tube so that the total amount of oxygen and water vapor in the gas G2 is 1 mol or more and 50 mol or less with respect to 1 mol of titanium tetrachloride. [1] The method for producing titanium oxide particles according to [2].
[4] In the first step, the gas G1 and the gas G2 are introduced into the reaction tube so that the amount of inert gas in the gas G1 is less than 3 mol with respect to 1 mol of titanium tetrachloride. 3] The method for producing titanium oxide particles according to any one of [3].
[5] Total Cl content a is 200 ppm by mass or less, and D 90 / D 50 measured by laser diffraction / scattering analysis method is X, and BET specific surface area measured by BET method by nitrogen adsorption is Y (m 2 / G), titanium oxide particles having X / Y of 0.060 or less.
[6] The inside of the titanium oxide particles obtained by subtracting the surface Cl content b (mass ppm) of the titanium oxide particles measured by the silver nitrate potentiometric titration method from the total Cl content a (mass ppm) in the titanium oxide particles. The titanium oxide particles according to claim 5, wherein the Cl content c is 200 ppm by mass or less.
[7] The titanium oxide particles according to [5] or [6], wherein the BET specific surface area Y is 20 to 200 m 2 / g.
[8] The titanium oxide particles according to any one of [5] to [7], wherein the content of titanium oxide is 99.9% by mass or more.
[9] The contents of Na, Al, S, Fe, Ni, Cr, Nb and Zr are each 10 mass ppm or less, and the contents of Si and C are 100 mass ppm or less, respectively [5] to [8] The titanium oxide particles according to any one of the above.
[10] A slurry containing the titanium oxide particles according to any one of [5] to [9].
[11] A dispersion containing the titanium oxide particles according to any one of [5] to [9].
[12] A composition comprising the titanium oxide particles according to any one of [5] to [9].
[13] A dielectric material obtained from the titanium oxide particles according to any one of [5] to [9].
本発明によれば、全Ｃｌ含有量ａが少なく、かつ均一性及び分散性に優れた酸化チタン粒子及びその製造方法、並びに当該酸化チタンを含むスラリー、分散体、組成物及び誘電体原料を提供することができる。 According to the present invention, titanium oxide particles having a low total Cl content a and excellent in uniformity and dispersibility, a method for producing the same, and a slurry, a dispersion, a composition, and a dielectric material containing the titanium oxide are provided. can do.
［酸化チタン粒子］
本発明の酸化チタン粒子は、全Ｃｌ含有量ａが２００質量ｐｐｍ以下であり、レーザー回折・散乱分析法により測定したＤ９０／Ｄ５０をＸとし、窒素吸着によるＢＥＴ法により測定したＢＥＴ比表面積をＹ（ｍ２／ｇ）とした場合、Ｘ／Ｙが０．０６０以下である酸化チタン粒子である。本発明の酸化チタン粒子は、全Ｃｌ含有量ａが少なく、かつ均一性及び分散性に優れる。かかる本発明の酸化チタン粒子は、後述する本発明の酸化チタン粒子の製造方法により、好適に製造することができる。
[Titanium oxide particles]
Titanium oxide particles of the present invention have a total Cl content a of 200 ppm by mass or less, D 90 / D 50 measured by laser diffraction / scattering analysis method as X, and BET specific surface area measured by BET method by nitrogen adsorption. Is a titanium oxide particle where X / Y is 0.060 or less, where Y is (m 2 / g). The titanium oxide particles of the present invention have a low total Cl content a and are excellent in uniformity and dispersibility. Such titanium oxide particles of the present invention can be preferably produced by the method for producing titanium oxide particles of the present invention described later.
本発明の酸化チタン粒子は、全Ｃｌ含有量ａが２００質量ｐｐｍ以下である。
全Ｃｌ含有量ａとは、酸化チタン粒子中におけるＣｌの総含有量のことであり、酸化チタンにフッ化水素酸を加えてマイクロウェーブ照射することにより溶解し、その溶液に硝酸銀溶液を滴下して、電位差を測定する硝酸銀電位差滴定法により測定された値のことをいう。
全Ｃｌ含有量ａが２００質量ｐｐｍを超えると、当該酸化チタン粒子をＢａＴｉＯ３等の原料に用いた場合、焼成時にフラックスの原因となる。溶融したフラックスは局在化し易く、その局在化した部分では凝集が多くなり、他の部分との間で品質にバラツキが生ずる。また、粒子が凝集するとＢａＴｉＯ３粒子の結晶が成長して異常粒子となり、ＢａＴｉＯ３の誘電特性を低下させることにもなる。当該観点から、酸化チタン粒子中における全Ｃｌ含有量ａは、好ましくは１８０質量ｐｐｍ以下、より好ましくは１５０質量ｐｐｍ以下、更に好ましくは１２０質量ｐｐｍ以下、より更に好ましくは１００質量ｐｐｍ以下、より更に好ましくは４０ｐｐｍ以下である。なお、４０ｐｐｍは、本測定方法における測定限界値である。
The titanium oxide particles of the present invention have a total Cl content a of 200 mass ppm or less.
The total Cl content a is the total content of Cl in the titanium oxide particles, which is dissolved by adding hydrofluoric acid to titanium oxide and irradiating with microwaves, and a silver nitrate solution is dropped into the solution. The value measured by the silver nitrate potentiometric titration method for measuring the potential difference.
When the total Cl content a exceeds 200 mass ppm, when the titanium oxide particles are used as a raw material such as BaTiO 3 , it causes a flux during firing. The melted flux is likely to be localized, the agglomeration increases in the localized part, and the quality varies with other parts. Further, when the particles are aggregated, crystals of BaTiO 3 particles grow to become abnormal particles, and the dielectric properties of BaTiO 3 are also deteriorated. From this viewpoint, the total Cl content a in the titanium oxide particles is preferably 180 ppm by mass or less, more preferably 150 ppm by mass or less, still more preferably 120 ppm by mass or less, still more preferably 100 ppm by mass or less, and even more. Preferably it is 40 ppm or less. 40 ppm is a measurement limit value in this measurement method.
表面Ｃｌ含有量ｂとは、酸化チタン粒子の表面におけるＣｌ含有量のことであり、同様の観点から、好ましくは２００質量ｐｐｍ以下、より好ましくは１８０質量ｐｐｍ以下、更に好ましくは１５０質量ｐｐｍ以下、より更に好ましくは１２０質量ｐｐｍ以下、より更に好ましくは１００質量ｐｐｍ以下である。
本発明において、表面Ｃｌ含有量ｂとは、酸化チタンを水に分散させてその溶液に硝酸銀溶液を滴下し、電位差を測定する硝酸銀電位差滴定法により測定された値のことをいう。
本測定方法における定量下限は４０ｐｐｍであり、測定された値が定量下限よりも低い場合を０ｐｐｍ以上４０ｐｐｍ未満であるとする。
The surface Cl content b is the Cl content on the surface of the titanium oxide particles, and from the same viewpoint, it is preferably 200 ppm by mass or less, more preferably 180 ppm by mass or less, still more preferably 150 ppm by mass or less, Still more preferably, it is 120 mass ppm or less, More preferably, it is 100 mass ppm or less.
In the present invention, the surface Cl content b means a value measured by a silver nitrate potentiometric titration method in which titanium oxide is dispersed in water, a silver nitrate solution is dropped into the solution, and a potential difference is measured.
The lower limit of quantification in this measurement method is 40 ppm, and the case where the measured value is lower than the lower limit of quantification is 0 ppm or more and less than 40 ppm.
また、粒子内部にＣｌを含有する酸化チタン粒子を原料としてＢａＴｉＯ３層等を製造すると、当該Ｃｌが経時的に当該層の表面まで拡散し、当該層が形成された基材を腐食、変質させるといった不都合が生じる。また、この酸化チタン粒子の内部に存在するＣｌは、水洗や乾燥等の簡単な脱Ｃｌ処理では除去しにくい。そのため、酸化チタン粒子表面だけでなく、粒子内部にもＣｌが存在しないことが望ましい。
当該観点から、内部Ｃｌ含有量ｃとは、酸化チタン粒子の内部におけるＣｌ含有量ｃであり、好ましくは２００質量ｐｐｍ以下であり、より好ましくは１２０質量ｐｐｍ以下、更に好ましくは１００質量ｐｐｍ以下である。
なお、本発明において、内部Ｃｌ含有量ｃとは、上記の（酸化チタン粒子中におけるＣｌの総含有量である）全Ｃｌ含有量ａから、（粒子表面におけるＣｌの含有量である）表面Ｃｌ含有量ｂを差し引いた値のことをいう。
Further, when a BaTiO 3 layer or the like is produced using titanium oxide particles containing Cl inside the raw material, the Cl diffuses over time to the surface of the layer, and the base material on which the layer is formed is corroded and altered. Inconvenience occurs. Further, Cl present inside the titanium oxide particles is difficult to remove by simple deCl treatment such as washing with water or drying. For this reason, it is desirable that Cl is not present not only on the surface of the titanium oxide particles but also inside the particles.
From this viewpoint, the internal Cl content c is the Cl content c inside the titanium oxide particles, preferably 200 ppm by mass or less, more preferably 120 ppm by mass or less, and still more preferably 100 ppm by mass or less. is there.
In the present invention, the internal Cl content c refers to the surface Cl (which is the Cl content on the particle surface) from the total Cl content a (which is the total Cl content in the titanium oxide particles). The value obtained by subtracting the content b.
本発明の酸化チタン粒子は、Ｎａ，Ａｌ，Ｓ，Ｆｅ，Ｎｉ，Ｃｒ，Ｎｂ及びＺｒの含有量がそれぞれ１０質量ｐｐｍ以下であることが好ましい。また、本発明の酸化チタン粒子は、Ｓｉ及びＣの含有量がそれぞれ１００質量ｐｐｍ以下であることが好ましい。このように不純物が少ないと、当該酸化チタン粒子を原料として誘電体を得たときに、不純物の存在により誘電特性が悪くなることが抑制される。また、当該酸化チタン粒子を光触媒又は太陽電池の用途に用いたときに、Ｆｅによる着色による透明性の低下が防止又は抑制され、また、Ａｌ、Ｓ等に起因する格子欠陥による光触媒又は太陽電池としての機能の低下が防止又は抑制される。
本発明の酸化チタン粒子は、酸化チタンの含有量が９９．９質量％以上であることが好ましく、これにより純度が高くなり、上記のような不純物による影響が小さい。なお、これら不純物および酸化チタンの含有量は、実施例の項に記載された測定方法による。
The titanium oxide particles of the present invention preferably have Na, Al, S, Fe, Ni, Cr, Nb, and Zr contents of 10 mass ppm or less, respectively. Moreover, it is preferable that content of Si and C is 100 mass ppm or less in the titanium oxide particle of this invention, respectively. Thus, when there are few impurities, when a dielectric material is obtained using the said titanium oxide particle as a raw material, it will be suppressed that a dielectric characteristic deteriorates by presence of an impurity. In addition, when the titanium oxide particles are used for photocatalysts or solar cell applications, the decrease in transparency due to coloring by Fe is prevented or suppressed, and as photocatalysts or solar cells due to lattice defects caused by Al, S, etc. The deterioration of the function is prevented or suppressed.
The titanium oxide particles of the present invention preferably have a titanium oxide content of 99.9% by mass or more, thereby increasing the purity and being less affected by the impurities as described above. In addition, content of these impurities and titanium oxide is based on the measuring method described in the term of the Example.
本発明の酸化チタン粒子は、レーザー回折・散乱分析法により測定したＤ９０／Ｄ５０をＸとし、窒素吸着によるＢＥＴ法により測定したＢＥＴ比表面積をＹ（ｍ２／ｇ）とした場合、Ｘ／Ｙが０．０６０以下である。
一般に、ＢＥＴ比表面積Ｙが大きい粒子ほど、表面エネルギーが高くなって凝集し易くなるため、粒径が不均一になり、Ｘ（Ｄ９０／Ｄ５０）の値が大きくなり易い。この値Ｘ（Ｄ９０／Ｄ５０）をＢＥＴ比表面積Ｙで除した値Ｘ／Ｙは、ＢＥＴ比表面積の影響を除いた均一性の指標とすることができ、このＸ／Ｙの値が小さいほど、均一性に優れているといえる。
均一性を向上させる観点から、このＸ／Ｙの値は、好ましくは０．０５５以下、より好ましくは０．０５０以下、更に好ましくは０．０４５以下、より更に好ましくは０．０４０以下、より更に好ましくは０．０３５以下である。
The titanium oxide particles of the present invention have a D 90 / D 50 measured by a laser diffraction / scattering analysis method as X, and a BET specific surface area measured by a BET method by nitrogen adsorption as Y (m 2 / g), X / Y is 0.060 or less.
In general, particles having a larger BET specific surface area Y have higher surface energy and are more likely to aggregate, so that the particle size becomes non-uniform and the value of X (D 90 / D 50 ) tends to increase. A value X / Y obtained by dividing the value X (D 90 / D 50 ) by the BET specific surface area Y can be used as an index of uniformity excluding the influence of the BET specific surface area, and the value of X / Y is small. It can be said that the uniformity is excellent.
From the viewpoint of improving uniformity, the value of X / Y is preferably 0.055 or less, more preferably 0.050 or less, still more preferably 0.045 or less, still more preferably 0.040 or less, and still more. Preferably it is 0.035 or less.
なお、粒子の粒度分布の測定法には、「超微粒子ハンドブック」齋藤進六監修，フジ・テクノシステム，ｐ９３，(１９９０)によると、沈降法、顕微鏡法、レーザー回折・散乱分析法（光散乱法）、直接計数法等があるが、このうち沈降法、直接計数法は測定可能な粒径が数百ｎｍ以上であり、粒径が１００ｎｍ以下の微粒子の粒度分布を測定するには不適である。また、顕微鏡法も対象試料のサンプリングや試料の前処理によって測定値が変動することもあり、好ましい測定法とはいえない。これに対し、レーザー回折・散乱分析法（光散乱法）は数ｎｍ〜数μｍの範囲で粒径を測定することができ、微粒子の測定に適している。レーザー回折・散乱分析法（光散乱法）による粒度分布の測定手順について以下に説明する。 The particle size distribution can be measured by the sedimentation method, microscopy method, laser diffraction / scattering analysis method (light scattering) according to “Ultrafine Particles Handbook” supervised by Shinji Saito, Fuji Techno System, p93, (1990). Method), direct counting method, etc., of which sedimentation method and direct counting method have a measurable particle size of several hundred nm or more and are not suitable for measuring the particle size distribution of fine particles having a particle size of 100 nm or less. is there. In addition, the microscopic method is not a preferable measuring method because the measured value may vary depending on the sampling of the target sample or the pretreatment of the sample. On the other hand, the laser diffraction / scattering analysis method (light scattering method) can measure the particle diameter in the range of several nm to several μm, and is suitable for the measurement of fine particles. The procedure for measuring the particle size distribution by the laser diffraction / scattering analysis method (light scattering method) will be described below.
酸化チタン粒子０．０５ｇに純水１００ｍｌ及び１０％ヘキサメタリン酸ソーダ水溶液１００μｌを加えたスラリーに、３分間超音波照射（５０ＫＨｚ、１００Ｗ）する。このスラリーをレーザー回折式粒度分布測定装置（島津ＳＡＬＤ ２０００Ｊ）にかけて、粒度分布を測定する。当該測定に基づいて、Ｄ５０（体積積算粒度分布における積算粒度で５０％の粒径（μｍ））、Ｄ９０（体積積算粒度分布における積算粒度で９０％の粒径（μｍ））、Ｘ（Ｄ９０／Ｄ５０）が求められる。
このようにして測定された粒度分布におけるＤ９０の値が小さければ、親水性溶媒に対して良好な分散性を示していると判断され、Ｄ９０の値は、好ましくは８μｍ以下より好ましくは５μｍ以下、更に好ましくは３．５μｍ以下、より更に好ましくは１μｍ以下である。
A slurry obtained by adding 100 ml of pure water and 100 μl of a 10% sodium hexametaphosphate aqueous solution to 0.05 g of titanium oxide particles is subjected to ultrasonic irradiation (50 KHz, 100 W) for 3 minutes. This slurry is subjected to a laser diffraction particle size distribution measuring device (Shimadzu SALD 2000J) to measure the particle size distribution. Based on the measurement, D 50 (50% particle size (μm) in cumulative particle size distribution in cumulative particle size distribution), D 90 (90% particle size in cumulative particle size distribution (μm)), X ( D 90 / D 50 ) is determined.
If the value of D 90 in the particle size distribution measured in this way is small, it is judged that the polymer has good dispersibility in a hydrophilic solvent, and the value of D 90 is preferably 8 μm or less, more preferably 5 μm. Hereinafter, it is further preferably 3.5 μm or less, and still more preferably 1 μm or less.
本発明の酸化チタン粒子における上記値Ｘ（Ｄ９０／Ｄ５０）は、酸化チタン粒子の均一性の向上の観点から、６．００以下、より好ましくは５．５０以下、更に好ましくは５．００以下、より更に好ましくは２．００以下、より更に好ましくは１．５０以下、より更に好ましくは１．４０以下である。 The value X (D 90 / D 50 ) in the titanium oxide particles of the present invention is 6.00 or less, more preferably 5.50 or less, and still more preferably 5.00, from the viewpoint of improving the uniformity of the titanium oxide particles. Hereinafter, it is more preferably 2.00 or less, still more preferably 1.50 or less, and still more preferably 1.40 or less.
また、本発明の酸化チタン粒子における上記ＢＥＴ比表面積Ｙ（ｍ２／ｇ）は、不純物が少なくかつ均一性及び分散性に優れる酸化チタン粒子を得る観点から、好ましくは２０〜２００ｍ２／ｇ、より好ましくは２０〜１９０ｍ２／ｇ、更に好ましくは２０〜１５０ｍ２／ｇ、より更に好ましくは２０〜１００ｍ２／ｇ、より更に好ましくは２０〜５０ｍ２／ｇである。 In addition, the BET specific surface area Y (m 2 / g) in the titanium oxide particles of the present invention is preferably 20 to 200 m 2 / g from the viewpoint of obtaining titanium oxide particles with few impurities and excellent uniformity and dispersibility. more preferably 20~190m 2 / g, more preferably 20~150m 2 / g, even more preferably 20 to 100 m 2 / g, still more preferably from 20 to 50 m 2 / g.
本発明の酸化チタン粒子におけるルチル化率は、幅広く制御できるが、紫外線遮蔽性や光触媒活性においては、一般に、ルチル型が好ましく、好ましくは３〜９５％、より好ましくは６〜９５％、更に好ましくは３０〜９５％、より更に好ましくは５０〜９５％、最も好ましくは５０〜９０％である。
ここで、ルチル化率とは、酸化チタン中におけるルチル型酸化チタンの含有量のことをいう。
The rutile ratio in the titanium oxide particles of the present invention can be widely controlled. However, in terms of ultraviolet shielding properties and photocatalytic activity, the rutile type is generally preferable, preferably 3 to 95%, more preferably 6 to 95%, and still more preferably. Is 30 to 95%, more preferably 50 to 95%, and most preferably 50 to 90%.
Here, the rutile ratio means the content of rutile type titanium oxide in titanium oxide.
［スラリー、分散体、組成物及び誘電体原料］
本発明のスラリー、分散体、組成物及び誘電体原料は、前述の酸化チタン粒子を含む。本発明のスラリー、分散体、組成物及び誘電体原料は、光触媒用途や太陽電池用途、誘電体用途等に好適である。
[Slurry, dispersion, composition, and dielectric material]
The slurry, dispersion, composition and dielectric material of the present invention contain the aforementioned titanium oxide particles. The slurry, dispersion, composition and dielectric material of the present invention are suitable for photocatalyst use, solar cell use, dielectric use and the like.
［酸化チタン粒子の製造方法］
本発明の酸化チタン粒子の製造方法は、四塩化チタン及び不活性ガスを含有するガスＧ１と、酸素及び水蒸気の少なくとも１種並びに不活性ガスを含有するガスＧ２とを、反応管に導入して反応させ、粗酸化チタン粒子を製造する第１工程と、該粗酸化チタン粒子を乾式脱塩素法で脱塩素する第２工程と、を有し、第１工程の反応管に導入する不活性ガスの総量が、四塩化チタン１モルに対して１モル以上５０モル以下であり、ガスＧ２中の不活性ガス量が、ガスＧ１中の不活性ガス１モルに対し、５モル以上である、酸化チタン粒子の製造方法である。
[Method for producing titanium oxide particles]
In the method for producing titanium oxide particles of the present invention, a gas G1 containing titanium tetrachloride and an inert gas and a gas G2 containing at least one of oxygen and water vapor and an inert gas are introduced into a reaction tube. An inert gas having a first step of reacting to produce crude titanium oxide particles and a second step of dechlorinating the crude titanium oxide particles by a dry dechlorination method, introduced into the reaction tube of the first step The total amount of is 1 mol or more and 50 mol or less with respect to 1 mol of titanium tetrachloride, and the amount of inert gas in the gas G2 is 5 mol or more with respect to 1 mol of inert gas in the gas G1. This is a method for producing titanium particles.
本発明によると、全Ｃｌ含有量ａが低く、かつ均一性及び分散性に優れる酸化チタン粒子を得ることができる。
すなわち、気相法により酸化チタン粒子を製造する場合、酸化チタン粒子中の全Ｃｌ含有量ａを少なくしようとして反応を十分に行うと、粒子の焼結や凝集が進み、比表面積が低下し、また、粒径の均一性及び粒子の分散性が低下する。一方、反応が十分ではないと、酸化チタン粒子中の全Ｃｌ含有量ａが多くなる。
本発明者らは、第１工程の反応管に導入する不活性ガスの総量を、四塩化チタン１モルに対して１モル以上５０モル以下とし、かつガスＧ２中の不活性ガス量をガスＧ１中の不活性ガス１モルに対し、５モル以上とすることにより、Ｃｌ含有量が低く、かつ均一性及び分散性に優れる酸化チタン粒子を得ることができることを見出し、本発明に至った。
According to the present invention, titanium oxide particles having a low total Cl content a and excellent uniformity and dispersibility can be obtained.
That is, when producing titanium oxide particles by a vapor phase method, if the reaction is sufficiently carried out in an attempt to reduce the total Cl content a in the titanium oxide particles, sintering and aggregation of the particles proceeds, the specific surface area decreases, In addition, the uniformity of particle size and the dispersibility of the particles are reduced. On the other hand, if the reaction is not sufficient, the total Cl content a in the titanium oxide particles increases.
The inventors set the total amount of the inert gas introduced into the reaction tube of the first step to 1 to 50 mol with respect to 1 mol of titanium tetrachloride, and set the amount of the inert gas in the gas G2 to the gas G1. It has been found that by setting the amount to 5 moles or more with respect to 1 mole of the inert gas, titanium oxide particles having a low Cl content and excellent uniformity and dispersibility can be obtained.
＜第１工程＞
第１工程では、四塩化チタン及び不活性ガスを含有するガスＧ１と、酸素及び水蒸気の少なくとも１種並びに不活性ガスを含有するガスＧ２とを、反応管に導入して反応させ、粗酸化チタン粒子を製造する。
この第１工程において、反応管に導入する不活性ガスの総量、即ち、ガスＧ１中の不活性ガスとガスＧ２中の不活性ガスとの合計量は、四塩化チタン１モルに対して１モル以上５０モル以下であり、かつ、ガスＧ２中の不活性ガス量が、ガスＧ１中の不活性ガス１モルに対し、５モル以上である。これにより、全Ｃｌ含有量ａの低減と、粒径の均一性及び粒子の分散性の向上という、相反する効果を得ることができる。
<First step>
In the first step, a gas G1 containing titanium tetrachloride and an inert gas, and a gas G2 containing at least one of oxygen and water vapor and an inert gas are introduced into the reaction tube and reacted, and crude titanium oxide is reacted. Produce particles.
In this first step, the total amount of the inert gas introduced into the reaction tube, that is, the total amount of the inert gas in the gas G1 and the inert gas in the gas G2, is 1 mol per 1 mol of titanium tetrachloride. The amount of the inert gas in the gas G2 is 5 mol or more with respect to 1 mol of the inert gas in the gas G1. Thereby, the conflicting effects of reduction of the total Cl content a and improvement of particle size uniformity and particle dispersibility can be obtained.
（反応管に導入する不活性ガスの総量）
反応管に導入する不活性ガスの総量は、上記のとおり、四塩化チタン１モルに対して１モル以上５０モル以下である。不活性ガスの総量が当該範囲より少ない場合、反応ゾーンにおける酸化チタン粒子密度が高まり、凝集、焼結し易くなる。ここで、「反応ゾーン」とは、原料合流部から、冷却空気の導入によって反応を終了させるまでの領域のことをいう。
一方、不活性ガスが前記範囲よりも多い場合、原料の反応性が低下し、四塩化チタンの酸化反応が完結せず、酸化チタン粒子内部の内部Ｃｌ含有量ｃが増え、結果的に全Ｃｌ含有量ａが増える。よって、全Ｃｌ含有量ａの少ない酸化チタン粒子を製造するには、四塩化チタンの酸化反応を完結させ、かつ凝集、焼結を抑制するような反応条件が必要であり、反応管内に導入する不活性ガスの総量は、四塩化チタンガス１モルに対し、好ましくは１モル以上３０モル以下、より好ましくは１モル以上２０モル以下、更に好ましくは１モル以上１０モル以下、より更に好ましくは１モル以上５モル以下である。
(Total amount of inert gas introduced into the reaction tube)
As described above, the total amount of the inert gas introduced into the reaction tube is 1 mol or more and 50 mol or less with respect to 1 mol of titanium tetrachloride. When the total amount of the inert gas is less than the range, the titanium oxide particle density in the reaction zone is increased, and aggregation and sintering are facilitated. Here, the “reaction zone” refers to a region from the raw material merging portion until the reaction is terminated by introducing cooling air.
On the other hand, when the inert gas is more than the above range, the reactivity of the raw material is lowered, the oxidation reaction of titanium tetrachloride is not completed, the internal Cl content c inside the titanium oxide particles is increased, and as a result, the total Cl Content a increases. Therefore, in order to produce titanium oxide particles having a low total Cl content a, reaction conditions that complete the oxidation reaction of titanium tetrachloride and suppress aggregation and sintering are necessary and introduced into the reaction tube. The total amount of the inert gas is preferably 1 mol or more and 30 mol or less, more preferably 1 mol or more and 20 mol or less, further preferably 1 mol or more and 10 mol or less, and still more preferably 1 mol with respect to 1 mol of titanium tetrachloride gas. More than 5 mol.
図１は、第１工程の好適な実施形態を示す模式図である。
先ず、反応管１内にガスＧ１及びガスＧ２を導入する。このとき、反応管１内へのガスＧ１及びガスＧ２の導入後の反応管１内温度が所定温度範囲内になるように、反応管１を予め加熱しておくことが好ましい。この反応管１内で原料ガス（ガスＧ１及びガスＧ２）を所定時間滞留させる。この反応管１内が、反応ゾーンＺとなる。
次いで、冷却媒体３として上記ガス又は水を反応管１と冷却管２の間に導入して、原料ガスを急冷し、反応生成物である粗酸化チタン粒子４を冷却媒体３と共に冷却管２から流出させる。これにより、粗酸化チタン粒子４を好適に製造することができる。得られた粗酸化チタン粒子は、第２工程５に送られる。
FIG. 1 is a schematic diagram showing a preferred embodiment of the first step.
First, gas G1 and gas G2 are introduced into the reaction tube 1. At this time, it is preferable to heat the reaction tube 1 in advance so that the temperature in the reaction tube 1 after the introduction of the gas G1 and the gas G2 into the reaction tube 1 is within a predetermined temperature range. The source gas (gas G1 and gas G2) is retained in the reaction tube 1 for a predetermined time. This reaction tube 1 is a reaction zone Z.
Next, the above gas or water is introduced as the cooling medium 3 between the reaction tube 1 and the cooling tube 2, the raw material gas is quenched, and the crude titanium oxide particles 4, which are reaction products, are discharged from the cooling tube 2 together with the cooling medium 3. Spill. Thereby, the crude titanium oxide particle 4 can be manufactured suitably. The obtained crude titanium oxide particles are sent to the second step 5.
（ガスＧ１）
ガスＧ１は、四塩化チタン及び不活性ガスを含有する。
ガスＧ１中において、四塩化チタン１モルに対する不活性ガスの含有量は、得られる酸化チタン粒子の粒径を小さく抑える観点から、好ましくは０．１モル以上、より好ましくは０．５モル以上、更に好ましくは１モル以上、より更に好ましくは１．５モル以上、より更に好ましくは２モル以上である。また、反応を促進させる観点から、好ましくは５０モル以下、より好ましくは２０モル以下、更に好ましくは１０モル以下、より更に好ましくは５モル以下、より更に好ましくは３モル以下である。
この不活性ガスとしては、窒素、ヘリウム、アルゴン等が挙げられるが、経済的な観点から窒素が好ましい。ガスＧ１中における上記四塩化チタン及び上記不活性ガスの合計含有量は、全Ｃｌ含有量ａが低く、かつ均一性及び分散性に優れる酸化チタン粒子を得る観点から、好ましくは８０モル％以上、より好ましくは９０モル％以上、更に好ましくは９５モル％以上、より更に好ましくは９９モル％以上である。
(Gas G1)
The gas G1 contains titanium tetrachloride and an inert gas.
In the gas G1, the content of the inert gas with respect to 1 mol of titanium tetrachloride is preferably 0.1 mol or more, more preferably 0.5 mol or more, from the viewpoint of suppressing the particle size of the obtained titanium oxide particles to be small. More preferably, it is 1 mol or more, More preferably, it is 1.5 mol or more, More preferably, it is 2 mol or more. From the viewpoint of promoting the reaction, it is preferably 50 mol or less, more preferably 20 mol or less, still more preferably 10 mol or less, still more preferably 5 mol or less, and still more preferably 3 mol or less.
Examples of the inert gas include nitrogen, helium, and argon. Nitrogen is preferable from an economical viewpoint. The total content of the titanium tetrachloride and the inert gas in the gas G1 is preferably 80 mol% or more from the viewpoint of obtaining titanium oxide particles having a low total Cl content a and excellent uniformity and dispersibility. More preferably, it is 90 mol% or more, More preferably, it is 95 mol% or more, More preferably, it is 99 mol% or more.
（ガスＧ２）
ガスＧ２は、酸素及び水蒸気の少なくとも１種並びに不活性ガスを含有する。
ガスＧ２中において、酸素及び水蒸気の総量１モルに対する不活性ガスの含有量は、好ましくは０．１モル以上５０モル以下である。５０モル以下であると、反応管内の原料濃度が高いため、反応が促進され、全Ｃｌ含有量ａおよび内部Ｃｌ含有量ｃを低減させることができる。また、０．１モル以上であると、内部Ｃｌ含有量ｃおよび全Ｃｌ含有量ａの少ない酸化チタン粒子を得ることができる。当該観点から、酸素及び水蒸気の総量１モルに対する不活性ガスの含有量は、より好ましくは０．１モル以上３０モル以下、更に好ましくは０．１モル以上２０モル以下、より更に好ましくは０．１モル以上１０モル以下、より更に好ましくは０．１モル以上５モル以下である。
(Gas G2)
The gas G2 contains at least one of oxygen and water vapor and an inert gas.
In the gas G2, the content of the inert gas with respect to 1 mol of the total amount of oxygen and water vapor is preferably 0.1 mol or more and 50 mol or less. When it is 50 mol or less, since the raw material concentration in the reaction tube is high, the reaction is promoted, and the total Cl content a and the internal Cl content c can be reduced. Further, when the amount is 0.1 mol or more, titanium oxide particles having a low internal Cl content c and a total Cl content a can be obtained. From this viewpoint, the content of the inert gas with respect to 1 mol of the total amount of oxygen and water vapor is more preferably 0.1 mol or more and 30 mol or less, still more preferably 0.1 mol or more and 20 mol or less, and still more preferably 0.8. It is 1 mol or more and 10 mol or less, More preferably, it is 0.1 mol or more and 5 mol or less.
この不活性ガスとしては、窒素、ヘリウム、アルゴン等が挙げられるが、経済的な観点から窒素が好ましい。ガスＧ２中の不活性ガスは、ガスＧ１中の不活性ガスと同じでも異なっていてもよいが、経済的な観点から共に窒素であることが好ましい。
このガスＧ２は、酸素及び水蒸気の少なくとも１種を含有していればよいが、Ｃｌ含有量が少なく、かつ均一性・分散性に優れた酸化チタン粒子を得る観点から、両方を含有することが好ましい。
同様の観点から、酸素１モルに対して、水蒸気は、好ましくは１モル以上、より好ましくは４モル以上、更に好ましくは１０モル以上、より更に好ましくは３０モル以上、より更に好ましくは４０モル以上であり、また、好ましくは１５０モル以下、より好ましくは１００モル以下、更に好ましくは８０モル以下、より更に好ましくは７０モル以下、より更に好ましくは６０モル以下である。
ガスＧ２中における上記酸素、水蒸気及び不活性ガスの合計含有量は、全Ｃｌ含有量ａが低く、かつ均一性及び分散性に優れる酸化チタン粒子を得る観点から、好ましくは８０モル％以上、より好ましくは９０モル％以上、更に好ましくは９５モル％以上、より更に好ましくは９９モル％以上である。
Examples of the inert gas include nitrogen, helium, and argon. Nitrogen is preferable from an economical viewpoint. The inert gas in the gas G2 may be the same as or different from the inert gas in the gas G1, but both are preferably nitrogen from an economical viewpoint.
The gas G2 only needs to contain at least one of oxygen and water vapor, but it may contain both from the viewpoint of obtaining titanium oxide particles with low Cl content and excellent uniformity and dispersibility. preferable.
From the same viewpoint, the water vapor is preferably 1 mol or more, more preferably 4 mol or more, still more preferably 10 mol or more, still more preferably 30 mol or more, still more preferably 40 mol or more with respect to 1 mol of oxygen. Also, it is preferably 150 mol or less, more preferably 100 mol or less, still more preferably 80 mol or less, still more preferably 70 mol or less, and still more preferably 60 mol or less.
The total content of oxygen, water vapor and inert gas in the gas G2 is preferably 80 mol% or more from the viewpoint of obtaining titanium oxide particles having a low total Cl content a and excellent uniformity and dispersibility. Preferably it is 90 mol% or more, More preferably, it is 95 mol% or more, More preferably, it is 99 mol% or more.
（不活性ガスのガスＧ１及びガスＧ２への配分）
酸化反応の進行を妨げることを防止し、かつ内部Ｃｌ含有量ｃ及び全Ｃｌ含有量ａの少ない酸化チタン粒子を得る観点から、ガスＧ２に導入する不活性ガス量は、ガスＧ１に導入する不活性ガス１モルに対して、５モル以上であり、好ましくは１０モル以上、より好ましくは２０モル以上、更に好ましくは３０モル以上であり、また、好ましくは１００モル以下、より好ましくは８０モル以下、更に好ましくは７０モル以下、より更に好ましくは６０モル以下である。
(Distribution of inert gas to gas G1 and gas G2)
From the viewpoint of preventing the progress of the oxidation reaction and obtaining titanium oxide particles having a low internal Cl content c and a total Cl content a, the amount of inert gas introduced into the gas G2 is the amount of inert gas introduced into the gas G1. The amount is 5 mol or more, preferably 10 mol or more, more preferably 20 mol or more, still more preferably 30 mol or more, and preferably 100 mol or less, more preferably 80 mol or less with respect to 1 mol of the active gas. More preferably, it is 70 mol or less, and still more preferably 60 mol or less.
（四塩化チタンと酸素及び水蒸気の総量との割合）
酸素及び水蒸気の反応管への総導入量は、四塩化チタンの反応管への導入量１モルに対して、好ましくは１モル以上５０モル以下、より好ましくは１モル以上２０モル以下である。酸素及び水蒸気の導入量を増やすと、酸化チタンの核発生数が増加し微粒子は得られやすくなるが、５０モルを越えても核発生数を増加させる効果はほとんど無い。酸素及び水蒸気の導入量が５０モルを越えても酸化チタンの特性に影響は無いが、経済的な観点から上限が設定される。一方、１モル以上であると、酸素欠陥が少なく着色のない酸化チタンを得ることができる。
(Ratio of titanium tetrachloride to the total amount of oxygen and water vapor)
The total amount of oxygen and water vapor introduced into the reaction tube is preferably 1 mol or more and 50 mol or less, more preferably 1 mol or more and 20 mol or less with respect to 1 mol of titanium tetrachloride introduced into the reaction tube. Increasing the amount of oxygen and water vapor introduced increases the number of nuclei of titanium oxide and makes it easier to obtain fine particles, but there is little effect of increasing the number of nuclei even when the amount exceeds 50 mol. Even if the introduction amount of oxygen and water vapor exceeds 50 mol, the characteristics of titanium oxide are not affected, but the upper limit is set from an economical viewpoint. On the other hand, when the amount is 1 mol or more, it is possible to obtain an uncolored titanium oxide with few oxygen defects.
（ガスＧ１とガスＧ２との割合）
ガスＧ２の反応管への導入量は、ガスＧ１の反応管への導入量１モルに対して、好ましくは１モル以上５０モル以下、より好ましくは１モル以上２０モル以下である。ガスＧ２のガス量を増やすと、酸化チタンの核発生数が増加し微粒子は得られやすくなるが、５０モルを越えても核発生数を増加させる効果はほとんど無い。ガスＧ２が５０モルを越えても酸化チタンの特性に影響は無いが、経済的な観点から上限が設定される。一方、１モル以上であると、酸素欠陥が少なく着色のない酸化チタンを得ることができる。
(Ratio of gas G1 and gas G2)
The amount of the gas G2 introduced into the reaction tube is preferably 1 mol or more and 50 mol or less, more preferably 1 mol or more and 20 mol or less, with respect to 1 mol of the gas G1 introduced into the reaction tube. Increasing the gas amount of the gas G2 increases the number of nuclei of titanium oxide and makes it easier to obtain fine particles. However, even if the amount exceeds 50 mol, there is almost no effect of increasing the number of nuclei generated. Even if the gas G2 exceeds 50 mol, there is no influence on the characteristics of the titanium oxide, but an upper limit is set from an economical viewpoint. On the other hand, when the amount is 1 mol or more, it is possible to obtain an uncolored titanium oxide with few oxygen defects.
（反応温度及び反応時間）
ガスＧ１及びガスＧ２を導入する反応管内の温度は、好ましくは９００℃以上１，２００℃未満、より好ましくは９００℃以上１，１００℃未満である。反応管内温度を高くすることによって、混合と同時に反応が完結し、均一核発生が増進され、かつ、反応ゾーンを小さくすることができる。反応管内温度が９００℃以上であると、反応が十分に進み、酸化チタン粒子の内部Ｃｌ含有量ｃが少なくなる。一方、反応管内温度が１，２００℃未満であると、粒子成長が抑制され、微粒子が得られる。
原料ガスが反応管に導入されると、急冷を施さないかぎり酸化チタン粒子が粒成長してしまい、また、粒子の焼結が進行してしまう。そこで、９００℃以上１，２００℃未満の高温滞留時間は、好ましくは０．１秒以下、より好ましくは０．０３秒以下、更に好ましくは０．０２秒以下である。
急冷の手段としては、例えば、反応混合物に多量の冷却空気や窒素等のガスを導入する方法、あるいは水を噴霧する方法等が好適に採用される。
(Reaction temperature and reaction time)
The temperature in the reaction tube into which the gas G1 and the gas G2 are introduced is preferably 900 ° C. or higher and lower than 1,200 ° C., more preferably 900 ° C. or higher and lower than 1,100 ° C. By increasing the temperature in the reaction tube, the reaction is completed simultaneously with mixing, the generation of uniform nuclei is promoted, and the reaction zone can be reduced. When the temperature in the reaction tube is 900 ° C. or higher, the reaction proceeds sufficiently, and the internal Cl content c of the titanium oxide particles decreases. On the other hand, when the temperature in the reaction tube is lower than 1,200 ° C., particle growth is suppressed and fine particles are obtained.
When the raw material gas is introduced into the reaction tube, the titanium oxide particles grow unless they are rapidly cooled, and the sintering of the particles proceeds. Therefore, the high temperature residence time of 900 ° C. or more and less than 1,200 ° C. is preferably 0.1 seconds or less, more preferably 0.03 seconds or less, and still more preferably 0.02 seconds or less.
As the rapid cooling means, for example, a method of introducing a large amount of cooling air or a gas such as nitrogen into the reaction mixture, a method of spraying water, or the like is preferably employed.
＜第２工程＞
第２工程では、第１工程で得られた粗酸化チタン粒子を、乾式脱塩素法で脱塩素する。
ここで、「乾式脱塩素法」とは、円筒形回転式加熱炉、熱風循環式加熱炉、流動乾燥炉、撹拌乾燥炉等の加熱装置を用いて水蒸気の存在下で粗酸化チタン粒子を加熱し、Ｃｌを除去する方法である。この加熱装置は、好ましくは円筒形回転式加熱炉である。
なお、脱塩素法には湿式脱塩素法もあるが、必ず乾燥工程を伴うため、酸化チタン粒子が凝集し、分散性が低くなる。
<Second step>
In the second step, the crude titanium oxide particles obtained in the first step are dechlorinated by a dry dechlorination method.
Here, the “dry dechlorination method” refers to heating crude titanium oxide particles in the presence of water vapor using a heating device such as a cylindrical rotary heating furnace, a hot-air circulating heating furnace, a fluidized drying furnace, or a stirring drying furnace. And removing Cl. This heating device is preferably a cylindrical rotary heating furnace.
In addition, although there exists a wet dechlorination method in a dechlorination method, since a drying process is necessarily accompanied, a titanium oxide particle aggregates and dispersibility becomes low.
粗酸化チタン粒子の加熱による脱塩素は、水蒸気と粗酸化チタン粒子との質量比（＝水蒸気の質量／粗酸化チタン粒子の質量。以下同様）が０．０１以上になるように酸化チタン粒子に水蒸気を接触させながら加熱することが好ましく、より好ましくは０．０３以上、更に好ましくは０．１以上である。
脱塩素は、酸化チタン表面のＣｌが粒子近傍の水あるいは隣接する粒子の表面水酸基と置換反応することにより進行する。酸化チタン粒子表面のＣｌが、水と置換された場合には粒成長せずに脱塩素化されるが、隣接する粒子の表面水酸基と置換された場合は脱塩素と同時に粒成長することとなる。すなわち、粒成長を抑制しつつ脱塩素化を図るためには、水蒸気と酸化チタンの質量比も重要であり、水蒸気と酸化チタンの質量比が０．０１以上であれば粒成長を抑制する効果が認められる。
The dechlorination by heating of the crude titanium oxide particles is applied to the titanium oxide particles so that the mass ratio of water vapor to the coarse titanium oxide particles (= mass of water vapor / mass of the coarse titanium oxide particles, the same applies hereinafter) is 0.01 or more. It is preferable to heat while making it contact with water vapor, more preferably 0.03 or more, and still more preferably 0.1 or more.
Dechlorination proceeds by substitution reaction of Cl on the surface of titanium oxide with water in the vicinity of the particles or surface hydroxyl groups of adjacent particles. When Cl on the surface of titanium oxide particles is replaced with water, it is dechlorinated without growing grains, but when it is replaced with the surface hydroxyl groups of adjacent particles, grains grow simultaneously with dechlorination. . That is, in order to achieve dechlorination while suppressing grain growth, the mass ratio of water vapor and titanium oxide is also important. If the mass ratio of water vapor and titanium oxide is 0.01 or more, the effect of suppressing grain growth Is recognized.
加熱温度は、好ましくは２００℃以上５５０℃以下、より好ましくは４００℃以上５５０℃以下である。５５０℃以下であると酸化チタン粒子の焼結が抑制され、粒成長が抑制される。加熱温度が２００℃以上であると、脱塩素の効率が高くなる。 The heating temperature is preferably 200 ° C. or higher and 550 ° C. or lower, more preferably 400 ° C. or higher and 550 ° C. or lower. When the temperature is 550 ° C. or lower, the sintering of the titanium oxide particles is suppressed, and the grain growth is suppressed. When the heating temperature is 200 ° C. or higher, the efficiency of dechlorination is increased.
酸化チタンと接触させる水蒸気は、空気と混合して使用することが好ましい。空気は酸化チタンから分離したＣｌを効率良く系外に移動させる役割を有する。また、水蒸気を含んだ空気は２００℃以上１，０００℃以下に加熱しておくことが好ましい。 It is preferable to use water vapor mixed with air in contact with titanium oxide. Air has a role of efficiently moving Cl separated from titanium oxide out of the system. The air containing water vapor is preferably heated to 200 ° C. or higher and 1,000 ° C. or lower.
以下、実施例及び比較例について具体的に説明するが、本発明はこれらに何ら限定されるものではない。
なお、酸化チタン粒子についての物性の測定方法は以下のとおりである。
Hereinafter, although an example and a comparative example are explained concretely, the present invention is not limited to these at all.
In addition, the measuring method of the physical property about a titanium oxide particle is as follows.
（１）ルチル化率
酸化チタン粒子中におけるルチル型酸化チタンの含有量（ルチル化率）は、粉末Ｘ線回折法により測定した。
すなわち、乾燥させた酸化チタン粒子について、測定装置としてＰＡＮａｌｙｔｉｃａｌ社製「Ｘ’ｐｅｒｔＰＲＯ」を用い、銅ターゲットを用い、Ｃｕ−Ｋα１線を用いて、管電圧４５ｋＶ、管電流４０ｍＡ、測定範囲２θ＝１０〜８０ｄｅｇ、サンプリング幅０．０１６７ｄｅｇ、走査速度０．０１９２ｄｅｇ／ｓの条件でＸ線回折測定を行った。
ルチル型結晶に対応する最大ピークのピーク高さ（Ｈｒ）、ブルッカイト型結晶に対応する最大ピークのピーク高さ（Ｈｂ）、及びアナターゼ型結晶に対応する最大ピークのピーク高さ（Ｈａ）を求め、以下の計算式により、酸化チタン粒子中におけるルチル型酸化チタンの含有量（ルチル化率）を求めた。
ルチル化率（％）＝｛Ｈｒ／（Ｈａ＋Ｈｂ＋Ｈｒ）｝×１００
（２）ＢＥＴ比表面積Ｙ
酸化チタン粒子のＢＥＴ比表面積Ｙ（ｍ２／ｇ）は、島津製作所製比表面積測定装置（機種はフローソーブＩＩ，２３００）で測定した。
(1) Rutile conversion ratio The content of rutile titanium oxide in the titanium oxide particles (rutile conversion ratio) was measured by a powder X-ray diffraction method.
That is, for the dried titanium oxide particles, “X'pertPRO” manufactured by PANalytical is used as a measuring device, a copper target is used, a Cu-Kα1 wire is used, a tube voltage is 45 kV, a tube current is 40 mA, and a measurement range is 2θ = 10. X-ray diffraction measurement was performed under the conditions of ˜80 deg, sampling width of 0.0167 deg, and scanning speed of 0.0192 deg / s.
Obtain the peak height (Hr) of the maximum peak corresponding to the rutile crystal, the peak height (Hb) of the maximum peak corresponding to the brookite crystal, and the peak height (Ha) of the maximum peak corresponding to the anatase crystal. The content (rutile ratio) of rutile titanium oxide in the titanium oxide particles was determined by the following calculation formula.
Rutile ratio (%) = {Hr / (Ha + Hb + Hr)} × 100
(2) BET specific surface area Y
The BET specific surface area Y (m 2 / g) of the titanium oxide particles was measured with a specific surface area measuring device (model: Flowsorb II, 2300) manufactured by Shimadzu Corporation.
（３）全Ｃｌ含有量ａ
硝酸銀電位差滴定法により、酸化チタン粒子中の全Ｃｌ含有量ａを測定した。
すなわち、酸化チタン粒子を秤量した。次いで、この酸化チタン粒子にフッ化水素酸を加えてマイクロウェーブ照射することにより溶解し、その溶液に硝酸銀溶液を滴下して、電位差を測定することにより、溶液中の塩素の質量を求めた。そして、酸化チタン粒子の質量と、溶液中の塩素の質量とから、酸化チタン粒子中の全Ｃｌ含有量ａを算出した。
（４）表面Ｃｌ含有量ｂ
硝酸銀電位差滴定法により、酸化チタン粒子中の表面Ｃｌ含有量ｂを測定した。
すなわち、酸化チタン粒子を秤量した。次いで、この酸化チタン粒子を水に分散させてその溶液に硝酸銀溶液を滴下し、電位差を測定することにより、溶液中の塩素の質量を求めた。そして、酸化チタン粒子の質量と、溶液中の塩素の質量とから、酸化チタン粒子中の表面Ｃｌ含有量ｂを算出した。
（５）内部Ｃｌ含有量ｃ
上記（３）及び（４）により得られた全Ｃｌ含有量ａから表面Ｃｌ含有量ｂを差し引くことにより、内部Ｃｌ含有量ｃを算出した。
(3) Total Cl content a
The total Cl content a in the titanium oxide particles was measured by a silver nitrate potentiometric titration method.
That is, the titanium oxide particles were weighed. Next, hydrofluoric acid was added to the titanium oxide particles and dissolved by microwave irradiation. A silver nitrate solution was dropped into the solution, and the potential difference was measured to determine the mass of chlorine in the solution. Then, the total Cl content a in the titanium oxide particles was calculated from the mass of the titanium oxide particles and the mass of chlorine in the solution.
(4) Surface Cl content b
The surface Cl content b in the titanium oxide particles was measured by a silver nitrate potentiometric titration method.
That is, the titanium oxide particles were weighed. Next, the titanium oxide particles were dispersed in water, a silver nitrate solution was dropped into the solution, and the potential difference was measured to determine the mass of chlorine in the solution. Then, the surface Cl content b in the titanium oxide particles was calculated from the mass of the titanium oxide particles and the mass of chlorine in the solution.
(5) Internal Cl content c
The internal Cl content c was calculated by subtracting the surface Cl content b from the total Cl content a obtained by (3) and (4) above.
（６）Ｄ５０、Ｄ９０、Ｘ（Ｄ９０／Ｄ５０）、及びＸ／Ｙ
酸化チタン粒子０．０５ｇに純水１００ｍｌ及び１０％ヘキサメタリン酸ソーダ水溶液１００μｌを加えたスラリーに、３分間超音波照射（５０ＫＨｚ、１００Ｗ）した。このスラリーを島津製作所製レーザー回折式粒度分布測定装置（ＳＡＬＤ（登録商標）―２０００Ｊ）にかけて、粒度分布を測定した。当該測定に基づいて、Ｄ５０（体積積算粒度分布における積算粒度で５０％の粒径（μｍ））、Ｄ９０（体積積算粒度分布における積算粒度で９０％の粒径（μｍ））、Ｘ（Ｄ９０／Ｄ５０）を求めた。また、このＸの値と、前記のＢＥＴ比表面積Ｙとから、Ｘ／Ｙを算出した。
(6) D 50 , D 90 , X (D 90 / D 50 ), and X / Y
A slurry obtained by adding 100 ml of pure water and 100 μl of 10% sodium hexametaphosphate aqueous solution to 0.05 g of titanium oxide particles was subjected to ultrasonic irradiation (50 KHz, 100 W) for 3 minutes. The slurry was subjected to a particle size distribution analyzer (SALD (registered trademark) -2000J) manufactured by Shimadzu Corporation to measure the particle size distribution. Based on the measurement, D 50 (50% particle size (μm) in cumulative particle size distribution in cumulative particle size distribution), D 90 (90% particle size in cumulative particle size distribution (μm)), X ( D 90 / D 50 ) was determined. X / Y was calculated from the value of X and the BET specific surface area Y.
（７）酸化チタン粒子中における酸化チタンの含有量
酸化チタン粒子中における酸化チタンの含有量は、「１００−不純物濃度の総和（質量％）」より求めた。
（８）その他の不純物の含有量
不純物測定方法は、以下に示すとおりである。
Ｆｅ：原子吸光法（日立ハイテクノロジーズ社製原子吸光計Ｚ−２３００型）
Ａｌ，Ｓｉ：蛍光Ｘ線分析法（ＸＲＦ）（理学電機工業社製サイマルテックス１０）
Ｃ，Ｓ：高周波誘導炉燃焼・赤外線吸収法
Ｎａ、Ｎｉ、Ｃｒ、Ｎｂ，Ｚｒ：誘導結合プラズマ-質量分析法
(7) Content of Titanium Oxide in Titanium Oxide Particles The content of titanium oxide in the titanium oxide particles was determined from “100—total impurity concentration (mass%)”.
(8) Content of other impurities The method for measuring impurities is as follows.
Fe: atomic absorption method (atomic absorption spectrometer Z-2300 manufactured by Hitachi High-Technologies Corporation)
Al, Si: X-ray fluorescence analysis (XRF) (simultex 10 manufactured by Rigaku Corporation)
C, S: high frequency induction furnace combustion / infrared absorption method Na, Ni, Cr, Nb, Zr: inductively coupled plasma-mass spectrometry
実施例１
＜第１工程＞
８．３Ｎｍ３／ｈｒ（Ｎは標準状態を意味する。以下同じ。）のガス状四塩化チタン（四塩化チタンの純度≧９９．９９質量％）を０．５Ｎｍ３／ｈｒの窒素ガスで希釈して得た四塩化チタン希釈ガス（ガスＧ１）と、０．５Ｎｍ３／ｈｒの酸素と３６Ｎｍ３／ｈｒの水蒸気に１８Ｎｍ３／ｈｒの不活性ガスを混合して得た酸化性ガス（ガスＧ２）とを、石英ガラス製反応器に導入した。９００℃以上１，２００℃未満の高温滞留時間を０．０２秒となるように冷却空気を反応管に導入後、ポリテトラフルオロエチレン製バグフィルターにて粗酸化チタン粒子を捕集した。各種ガスの使用量を表１に示す。
Example 1
<First step>
Gaseous titanium tetrachloride (purity of titanium tetrachloride ≧ 99.99% by mass) of 8.3 Nm 3 / hr (N means the standard state, the same shall apply hereinafter) is diluted with 0.5 Nm 3 / hr of nitrogen gas. titanium tetrachloride diluted gas obtained by (gas G1), 0.5Nm 3 / hr of oxygen and 36 Nm 3 / hr of steam to 18 Nm 3 / hr of an oxidizing gas obtained by mixing an inert gas (gas G2) was introduced into a quartz glass reactor. Cooling air was introduced into the reaction tube so that the high temperature residence time of 900 ° C. or more and less than 1,200 ° C. was 0.02 seconds, and then the crude titanium oxide particles were collected with a polytetrafluoroethylene bag filter. Table 1 shows the amounts of various gases used.
＜第２工程＞
得られた粗酸化チタン粒子を円筒形回転式加熱炉に通し、水蒸気と粗酸化チタンとの質量比（水蒸気の質量／粗酸化チタン粒子の質量）が０．７、加熱温度５１０℃で脱Ｃｌして、酸化チタン粒子を得て、各種物性を測定した。その測定結果を表３に示す。
<Second step>
The obtained crude titanium oxide particles are passed through a cylindrical rotary heating furnace, and the mass ratio of water vapor to crude titanium oxide (mass of water vapor / mass of crude titanium oxide particles) is 0.7, and deCl is applied at a heating temperature of 510 ° C. Then, titanium oxide particles were obtained and various physical properties were measured. The measurement results are shown in Table 3.
実施例２〜７、比較例１〜２
第1工程のガス量、高温滞留時間を表１又は表２に示すとおりにしたこと以外は実施例１と同様にして、第１工程を実施した。
次いで、第２工程の水と粗酸化チタンの質量比、加熱温度を表１又は表２に示す通りにしたこと以外は、実施例１と同様にして、第２工程を実施した。測定結果を表３又は表４に示す。
Examples 2-7, Comparative Examples 1-2
The first step was performed in the same manner as in Example 1 except that the gas amount and the high temperature residence time in the first step were as shown in Table 1 or Table 2.
Next, the second step was carried out in the same manner as in Example 1 except that the mass ratio of water and crude titanium oxide in the second step and the heating temperature were as shown in Table 1 or Table 2. The measurement results are shown in Table 3 or Table 4.
比較例３
特開２００７−３１４４１８号公報に記載されている製造条件により酸化チタン粒子を得た。詳細を以下に示す。
１１．８Ｎｍ３／ｈｒのガス状四塩化チタンを８Ｎｍ３／ｈｒの不活性ガスで希釈した四塩化チタン希釈ガスを９００℃で予熱し、８Ｎｍ３／ｈｒの酸素と３２Ｎｍ３／ｈｒの水蒸気を混合した酸化性ガスを８００℃で予熱し、石英ガラス製反応器に導入した。８００℃以上１，０００℃未満の高温滞留時間を０．０１秒となるように冷却空気を反応管に導入後、ポリテトラフルオロエチレン製バグフィルターにて微粒子状酸化チタン粒子を捕集した。
得られた酸化チタンを円筒形回転式加熱炉に通し、水と酸化チタンの質量比を０．０２、加熱温度４５０℃で脱Ｃｌし、酸化チタン粒子を得た。得られた酸化チタン粒子の全Ｃｌ含有量ａは２００質量ｐｐｍを超えており、Ｘ／Ｙは０．０６０より大きい。
ガス量を表２に示し、酸化チタン粒子の物性の測定結果を表４に示す。
Comparative Example 3
Titanium oxide particles were obtained under the production conditions described in JP-A-2007-314418. Details are shown below.
11.8 Nm 3 / hr gaseous titanium tetrachloride diluted with 8 Nm 3 / hr inert gas is diluted with titanium tetrachloride dilution gas at 900 ° C., and 8 Nm 3 / hr oxygen and 32 Nm 3 / hr water vapor are added. The mixed oxidizing gas was preheated at 800 ° C. and introduced into a quartz glass reactor. Cooling air was introduced into the reaction tube so that the high-temperature residence time of 800 ° C. or more and less than 1,000 ° C. was 0.01 seconds, and then the particulate titanium oxide particles were collected with a polytetrafluoroethylene bag filter.
The obtained titanium oxide was passed through a cylindrical rotary heating furnace, and dechlorinated at a mass ratio of water to titanium oxide of 0.02 and a heating temperature of 450 ° C. to obtain titanium oxide particles. The total titanium content a of the obtained titanium oxide particles exceeds 200 ppm by mass, and X / Y is larger than 0.060.
The amount of gas is shown in Table 2, and the measurement results of the physical properties of the titanium oxide particles are shown in Table 4.
比較例４
特開２００７−３１４４１８号公報に記載されている、表２に記載した製造条件に変えた以外は比較例３と同様にして酸化チタン粒子を得た。
ガス量を表２に示し、酸化チタン粒子の物性の測定結果を表４に示す。
Comparative Example 4
Titanium oxide particles were obtained in the same manner as in Comparative Example 3, except that the production conditions described in JP-A 2007-314418 were changed to the production conditions described in Table 2.
The amount of gas is shown in Table 2, and the measurement results of the physical properties of the titanium oxide particles are shown in Table 4.
比較例５
特開２０１１−５７５５２に記載されている、表２に記載した製造条件に変えた以外は比較例３と同様にして酸化チタン粒子を得た。
ガス量を表２に示し、酸化チタン粒子の物性の測定結果を表４に示す。
Comparative Example 5
Titanium oxide particles were obtained in the same manner as in Comparative Example 3 except that the production conditions described in Table 2 were changed to those described in JP-A-2011-57552.
The amount of gas is shown in Table 2, and the measurement results of the physical properties of the titanium oxide particles are shown in Table 4.
比較例６
特開平１０−２５１０２１に記載されている、表２に記載した製造条件に変えた以外は比較例３と同様にして酸化チタン粒子を得た。
ガス量を表２に示し、酸化チタン粒子の物性の測定結果を表４に示す。
Comparative Example 6
Titanium oxide particles were obtained in the same manner as in Comparative Example 3 except that the production conditions described in JP-A-10-251021 were changed to the production conditions described in Table 2.
The amount of gas is shown in Table 2, and the measurement results of the physical properties of the titanium oxide particles are shown in Table 4.
比較例７
特開２００３−２７７０５７に記載されている、表２に記載した製造条件に変えた以外は比較例３と同様にして酸化チタン粒子を得た。
ガス量を表２に示し、酸化チタン粒子の物性の測定結果を表４に示す。
Comparative Example 7
Titanium oxide particles were obtained in the same manner as in Comparative Example 3 except that the production conditions described in JP-A-2003-277057 were changed to those shown in Table 2.
The amount of gas is shown in Table 2, and the measurement results of the physical properties of the titanium oxide particles are shown in Table 4.
本発明により、同等のＢＥＴ比表面積を有する従来の酸化チタンに比べ、不純物が少なくかつ均一性・分散性に優れた気相法の酸化チタン粒子及びこれらの製造方法が提供される。本発明の酸化チタンは、光触媒用途や太陽電池用途、誘電体用途等に好適であり、粉体としても解砕工程等が不要もしくは極めて軽微な設備で済み、工業的に非常に大きな実用的価値を有するものである。 According to the present invention, there are provided titanium oxide particles of a vapor phase method having less impurities and excellent uniformity and dispersibility as compared with conventional titanium oxide having an equivalent BET specific surface area, and a method for producing them. The titanium oxide of the present invention is suitable for photocatalyst use, solar cell use, dielectric use, etc., and it does not require a crushing process or the like even as a powder, and it requires very light equipment, and has a very large practical value industrially. It is what has.
１ 反応管
２ 冷却管
３ 冷却媒体（空気、窒素、水等）
４ 粗酸化チタン粒子
５ 第２工程
Ｇ１ ガスＧ１
Ｇ２ ガスＧ２
Ｚ 反応ゾーン
1 Reaction tube 2 Cooling tube 3 Cooling medium (air, nitrogen, water, etc.)
4 Crude titanium oxide particles 5 Second step G1 Gas G1
G2 Gas G2
Z reaction zone
Claims (10)
レーザー回折・散乱分析法により測定したＤ９０／Ｄ５０をＸとし、窒素吸着によるＢＥＴ法により測定したＢＥＴ比表面積をＹ（ｍ２／ｇ）とした場合、Ｘ／Ｙが０．０６０以下であり、
Ｘが１．５０以下である粉末の酸化チタン粒子。 The total Cl content a is 200 mass ppm or less,
When D 90 / D 50 measured by the laser diffraction / scattering analysis method is X, and the BET specific surface area measured by the BET method by nitrogen adsorption is Y (m 2 / g), X / Y is 0.060 or less. Yes,
Powdered titanium oxide particles wherein X is 1.50 or less.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001220141A (en) * | 2000-02-03 | 2001-08-14 | Toho Titanium Co Ltd | Titanium oxide dispersion |
| JP2005104796A (en) * | 2003-10-01 | 2005-04-21 | Toho Titanium Co Ltd | Method of manufacturing titanium oxide powder |
| JP2006001775A (en) * | 2004-06-16 | 2006-01-05 | Toho Titanium Co Ltd | Titanium oxide dispersion and its producing method |
| JP2006265094A (en) * | 2005-02-28 | 2006-10-05 | Showa Denko Kk | Particulate titanium dioxide, its manufacturing method, and its application |
| JP2007176753A (en) * | 2005-12-28 | 2007-07-12 | Sumitomo Osaka Cement Co Ltd | High-crystallinity anatase-type titanium oxide ultra-fine particle controlled in particle shape and production method thereof |
| JP2010202486A (en) * | 2009-03-06 | 2010-09-16 | Toho Titanium Co Ltd | Production method of particulate titanium oxide powder and particulate titanium oxide powder |
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001220141A (en) * | 2000-02-03 | 2001-08-14 | Toho Titanium Co Ltd | Titanium oxide dispersion |
| JP2005104796A (en) * | 2003-10-01 | 2005-04-21 | Toho Titanium Co Ltd | Method of manufacturing titanium oxide powder |
| JP2006001775A (en) * | 2004-06-16 | 2006-01-05 | Toho Titanium Co Ltd | Titanium oxide dispersion and its producing method |
| JP2006265094A (en) * | 2005-02-28 | 2006-10-05 | Showa Denko Kk | Particulate titanium dioxide, its manufacturing method, and its application |
| JP2007176753A (en) * | 2005-12-28 | 2007-07-12 | Sumitomo Osaka Cement Co Ltd | High-crystallinity anatase-type titanium oxide ultra-fine particle controlled in particle shape and production method thereof |
| JP2010202486A (en) * | 2009-03-06 | 2010-09-16 | Toho Titanium Co Ltd | Production method of particulate titanium oxide powder and particulate titanium oxide powder |
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