JPH04198014A - Removal of chlorine in aluminum oxide and gas sensor - Google Patents
Removal of chlorine in aluminum oxide and gas sensorInfo
- Publication number
- JPH04198014A JPH04198014A JP32258790A JP32258790A JPH04198014A JP H04198014 A JPH04198014 A JP H04198014A JP 32258790 A JP32258790 A JP 32258790A JP 32258790 A JP32258790 A JP 32258790A JP H04198014 A JPH04198014 A JP H04198014A
- Authority
- JP
- Japan
- Prior art keywords
- chlorine
- aluminum oxide
- powder
- gas sensor
- al2o3
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910052801 chlorine Inorganic materials 0.000 title claims abstract description 78
- 239000000460 chlorine Substances 0.000 title claims abstract description 78
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 title claims abstract description 76
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 title claims description 80
- 239000000843 powder Substances 0.000 claims abstract description 36
- 238000010438 heat treatment Methods 0.000 claims abstract description 19
- 239000003054 catalyst Substances 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 23
- 238000006460 hydrolysis reaction Methods 0.000 claims description 10
- 230000007062 hydrolysis Effects 0.000 claims description 8
- 239000010970 precious metal Substances 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 abstract description 35
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 34
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 abstract description 10
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 abstract description 8
- 239000002245 particle Substances 0.000 abstract description 8
- 229910000510 noble metal Inorganic materials 0.000 abstract description 3
- 230000003301 hydrolyzing effect Effects 0.000 abstract description 2
- 229910044991 metal oxide Inorganic materials 0.000 abstract description 2
- 150000004706 metal oxides Chemical class 0.000 abstract description 2
- 230000002093 peripheral effect Effects 0.000 abstract description 2
- 239000004065 semiconductor Substances 0.000 abstract description 2
- 229910052593 corundum Inorganic materials 0.000 abstract 5
- 229910001845 yogo sapphire Inorganic materials 0.000 abstract 5
- 230000003197 catalytic effect Effects 0.000 abstract 1
- 239000000758 substrate Substances 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 48
- 230000035945 sensitivity Effects 0.000 description 11
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 9
- 239000000463 material Substances 0.000 description 9
- 230000007797 corrosion Effects 0.000 description 8
- 238000005260 corrosion Methods 0.000 description 8
- 238000009283 thermal hydrolysis Methods 0.000 description 7
- 239000000919 ceramic Substances 0.000 description 6
- 230000006866 deterioration Effects 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 4
- 239000000969 carrier Substances 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000008204 material by function Substances 0.000 description 3
- 229910052697 platinum Inorganic materials 0.000 description 3
- 238000010298 pulverizing process Methods 0.000 description 3
- 239000010948 rhodium Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 150000001804 chlorine Chemical class 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 229910052763 palladium Inorganic materials 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 241001411320 Eriogonum inflatum Species 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- -1 aluminum organic compound Chemical class 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012776 electronic material Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 238000004255 ion exchange chromatography Methods 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
- 239000002574 poison Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
Description
【発明の詳細な説明】
［発明の目的］
（産業上の利用分野）
本発明は、電子機能材料や構造材料の素材原料として用
いられる酸化アルミニウムに含有される塩素を除去する
ための酸化アルミニウム中の塩素除去方法及び酸化アル
ミニウムを触媒層の担体として用いたガスセンサに関す
る。Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention is directed to a method for removing chlorine contained in aluminum oxide, which is used as a raw material for electronic functional materials and structural materials. The present invention relates to a chlorine removal method and a gas sensor using aluminum oxide as a carrier for a catalyst layer.
（従来の技術）
酸化アルミニウム（Ａ Ｉ ２０３ ）は、電子機能材
料（触媒担体、ガスセンサ、蛍光体、ＹＡＧレーザ素子
、磁性体担体、透光性セラミックス等）や構造材料（フ
ァインセラミックス等）の素材原料として、多くの分野
で多用されている。そして、近年電子材料の技術革新に
伴い、酸化アルミニウム原料の高品質化、すなわち数１
００Ａレベルの超微細化とともに高純度化が不可欠とな
っている。(Prior art) Aluminum oxide (AI 203) is a material for electronic functional materials (catalyst carriers, gas sensors, phosphors, YAG laser elements, magnetic carriers, translucent ceramics, etc.) and structural materials (fine ceramics, etc.). It is widely used as a raw material in many fields. In recent years, with technological innovations in electronic materials, the quality of aluminum oxide raw materials has improved, that is, the number 1
Along with ultra-fine design at the 00A level, high purity has become essential.
しかし、この酸化アルミニウムは塩化アルミニウム（Ａ
ｌＣｌ２）を原料として製造されるため、通常残留塩素
を数千ｐｐｍ以上含有しており、この含有塩素が材料特
性や、部品の腐食等により材料の信頼性に大きな悪影響
を与えていた。However, this aluminum oxide is aluminum chloride (A
Since they are manufactured using lCl2) as a raw material, they usually contain several thousand ppm or more of residual chlorine, and this chlorine content has had a significant negative impact on the reliability of the material due to material properties and corrosion of parts.
例えば、アルミナ担体触媒の場合には、残留塩素が担体
上のＰｔ、Ａｕ等の触媒の被毒物質として働き、触媒の
機能が減退あるいは機能を失い、触媒の使用寿命が低下
することが多い。また、蛍光体材料の場合には残留塩素
が多いと発光輝度特性が低下し、ファインラセミックス
部品の場合には残留塩素が装置、治具を腐食する。特に
、上記アルミナ担体触媒を用いるガスセンサの場合には
、残留塩素が触媒機能を低下させる上に、アルミナが環
境中で加水分解を起して塩素がガス感応体に付着し、セ
ンサ感度が不安定になりやすい。そのためガスセンサの
感度、選択性が低下することが多い。さらに、ガスセン
サの電極やボンディングワイヤ、ポンディングパッド等
の電気回路の配線部分等が塩素により腐食するという問
題が生じる。For example, in the case of an alumina-supported catalyst, residual chlorine acts as a poison for the catalyst, such as Pt or Au, on the support, often reducing or losing the function of the catalyst and shortening the usable life of the catalyst. Furthermore, in the case of phosphor materials, if there is a large amount of residual chlorine, the emission brightness characteristics will deteriorate, and in the case of fine racemic parts, residual chlorine will corrode equipment and jigs. In particular, in the case of a gas sensor that uses the alumina-supported catalyst mentioned above, residual chlorine not only reduces the catalyst function, but also causes hydrolysis of alumina in the environment, causing chlorine to adhere to the gas sensing element, making the sensor sensitivity unstable. easy to become. Therefore, the sensitivity and selectivity of the gas sensor often decrease. Furthermore, there arises a problem that the electrodes of the gas sensor, bonding wires, bonding pads, and other wiring parts of the electric circuit are corroded by chlorine.
このような残留塩素の悪影響を防ぐためには、酸化アル
ミニウムの塩素含有量を１００ ｐｐｍ以下に低減する
必要がある。従来は、アルミニウム溶液（塩化物、硝酸
塩、硫酸塩等）を加水分解して水酸化アルミニウムを生
成し、これを熱処理して得られる酸化アルミニウムを粉
砕等により微細化して酸化アルミニウムの粉末を製造し
ていた。しかし、この方法により製造された酸化アルミ
ニウムは、通常１１０００ｐｐ以上の多量の塩素を含有
していた。また、他の酸化アルミニウム製造方法として
、アルミニウム有機化合物を原料として微細酸化アルミ
ニウムを製造する方法があるが、コストアップとなるた
めこの方法はあまり採用されていなかった。In order to prevent such adverse effects of residual chlorine, it is necessary to reduce the chlorine content of aluminum oxide to 100 ppm or less. Conventionally, aluminum hydroxide was produced by hydrolyzing an aluminum solution (chloride, nitrate, sulfate, etc.), and the aluminum oxide obtained by heat treatment was pulverized to produce aluminum oxide powder. was. However, aluminum oxide produced by this method usually contains a large amount of chlorine, usually 11,000 pp or more. Further, as another method for producing aluminum oxide, there is a method for producing fine aluminum oxide using an aluminum organic compound as a raw material, but this method has not been widely adopted because it increases costs.
（発明が解決しようとする課題）
上述したように、従来酸化アルミニウムは残留塩素量が
多く、低純度、低品質であり、そのためにアルミナ担体
触媒を用いるガスセンサの感度、選択性が低下したり、
配線部分等に腐食が生じることが多いという問題があっ
た。(Problems to be Solved by the Invention) As mentioned above, conventional aluminum oxide has a large amount of residual chlorine, low purity, and low quality, which reduces the sensitivity and selectivity of gas sensors using alumina carrier catalysts.
There was a problem in that corrosion often occurred in wiring parts and the like.
本発明は上記した従来技術の課題を解決するためになさ
れたもので、その目的とするところは、残留塩素量が少
ない高純度、高品質の酸化アルミニウムを得ることがで
きる酸化アルミニウム中の塩素除去方法、及び感度、選
択性が安定し、電極や配線部分等に腐食が生じることが
少ない高品質のガスセンサを提供することにある。The present invention has been made in order to solve the problems of the prior art described above, and its purpose is to remove chlorine from aluminum oxide so that high purity and high quality aluminum oxide with a small amount of residual chlorine can be obtained. The object of the present invention is to provide a high-quality gas sensor with stable method, sensitivity, and selectivity, and with less corrosion in electrodes, wiring parts, etc.
［発明の構成コ
（課題を解決するための手段）
上記目的を達成するために、本発明の酸化アルミニウム
中の塩素除去方法にあっては、塩素を含む酸化アルミニ
ウムの粉末に水蒸気を供給しながら該粉末を加熱し、加
水分解により生じた排気ガスを取り除くことによって該
粉末から塩素を除去することを特徴とする。[Configuration of the Invention (Means for Solving the Problem) In order to achieve the above object, in the method for removing chlorine from aluminum oxide of the present invention, while supplying water vapor to aluminum oxide powder containing chlorine, The method is characterized in that chlorine is removed from the powder by heating the powder and removing exhaust gas generated by hydrolysis.
また、本発明のガスセンサは、貴金属が担体に担持され
て成る触媒層がガス感応体の表面に設けられたガスセン
サにおいて、担体が、上記の方法により製造され塩素濃
度が１１００ｐｐ以下とされた酸化アルミニウムから成
ることを特徴とする。Further, the gas sensor of the present invention is a gas sensor in which a catalyst layer in which a precious metal is supported on a carrier is provided on the surface of a gas sensitive body, in which the carrier is aluminum oxide manufactured by the above method and whose chlorine concentration is 1100 pp or less. It is characterized by consisting of.
上記酸化アルミニウム中の塩素除去方法において、塩素
を含む酸化アルミニウムの粉末は前記従来方法により製
造されたものでよいが、酸化アルミニウムの粒子径は１
０００Å以下とすることが好ましく、５００Å以下がよ
り好ましい。粒子径が１００ＯＡ以上の大粒子とすると
、酸化アルミニウムの粉末と水蒸気との接触面積が小さ
くなるのて、加水分解の反応速度が遅くなり、塩素除去
効率が著しく低下するためである。In the method for removing chlorine from aluminum oxide, the aluminum oxide powder containing chlorine may be one produced by the conventional method, but the particle size of the aluminum oxide is 1.
The thickness is preferably 000 Å or less, more preferably 500 Å or less. This is because if the particles are large particles with a diameter of 100 OA or more, the contact area between the aluminum oxide powder and water vapor becomes small, resulting in a slow hydrolysis reaction rate and a significant drop in chlorine removal efficiency.
上記加水分解処理を行うための装置としては、例えば、
酸化アルミニウムの粉末を収容する反応室と、この反応
室を加熱する加熱手段とを備え、反応室内に水蒸気を供
給しながら反応室を加熱し、このとき生じるガスを反応
室外へ排出するような構造のものが挙げられる。酸化ア
ルミニウムの粉末の加熱温度としては、加熱時の上記反
応室内の温度が２５０〜６００℃の範囲であることが好
ましく、さらに４００〜５００℃の範囲であることがよ
り好ましい。上記温度が２５０℃未満では酸化アルミニ
ウムの加水分解が不完全となり、塩素の除去が不充分と
なる。一方、この温度が６００℃より高いと、酸化アル
ミニウムの結晶粒子の成長が促進されて結晶粒子が大き
くなり、粉砕等により微細化したときの酸化アルミニウ
ムの純度が悪くなり低品質となるので好ましくない。Examples of equipment for performing the above hydrolysis treatment include:
A structure comprising a reaction chamber containing aluminum oxide powder and a heating means for heating the reaction chamber, heating the reaction chamber while supplying water vapor into the reaction chamber, and discharging the gas generated at this time to the outside of the reaction chamber. Examples include: As for the heating temperature of the aluminum oxide powder, the temperature inside the reaction chamber during heating is preferably in the range of 250 to 600°C, and more preferably in the range of 400 to 500°C. If the temperature is less than 250°C, the hydrolysis of aluminum oxide will be incomplete and chlorine will be insufficiently removed. On the other hand, if this temperature is higher than 600°C, the growth of crystal particles of aluminum oxide will be promoted and the crystal particles will become larger, and when the aluminum oxide is refined by pulverization, the purity of the aluminum oxide will deteriorate and the quality will be low, which is undesirable. .
また、供給する水蒸気の温度としては、７０℃以上が好
ましく、９０℃以上がより好ましい。なぜならば、水蒸
気の温度が７０℃より低いと上記加水分解の反応時間が
長くなり、塩素除去効率が低下するからである。Further, the temperature of the supplied water vapor is preferably 70°C or higher, more preferably 90°C or higher. This is because if the temperature of the steam is lower than 70°C, the reaction time for the hydrolysis becomes longer and the chlorine removal efficiency decreases.
上述した塩素除去方法によれば、酸化アルミニウム中の
塩素を高効率で除去して、含有塩素量の少ない高品質の
酸化アルミニウムを得ることが可能となる。According to the above-described chlorine removal method, it is possible to remove chlorine in aluminum oxide with high efficiency and obtain high-quality aluminum oxide with a small amount of chlorine content.
本発明のガスセンサは、上記方法により残留塩素が除去
されて塩素濃度がｉｏｏｐｐｍ以下とされた酸化アルミ
ニウムを、触媒層における担体として用いている。この
意思外は従来のガスセンサと同様な構成であり、１対の
電極を備えたガス感応体の表面に、バナジウム（Ｖ）、
ロジウム（Ｒｈ）、パラジウム（Ｐｄ）、白金（ｐｔ）
、金（Ａｕ）等の貴金属が上記酸化アルミニウムの担体
に担持されて成る触媒層が設けられている。In the gas sensor of the present invention, aluminum oxide from which residual chlorine has been removed by the above method to have a chlorine concentration of iooppm or less is used as a carrier in the catalyst layer. Other than this, the structure is similar to that of conventional gas sensors, with vanadium (V),
Rhodium (Rh), Palladium (Pd), Platinum (pt)
A catalyst layer is provided in which a noble metal such as gold (Au) is supported on the aluminum oxide carrier.
（作用）
本発明の酸化アルミニウム中の塩素除去方法においては
、塩素を含有する酸化アルミニウムの粉末へ水蒸気の供
給、加熱を行うことにより、次式の反応が速やかに進行
する。(Function) In the method for removing chlorine from aluminum oxide of the present invention, by supplying water vapor to aluminum oxide powder containing chlorine and heating it, the reaction of the following formula proceeds rapidly.
２Ａ Ｉ Ｃ１３＋３Ｈ２０
→Ａ １２０ｉ ＋６ＨＣ１・・・（１）すなわち、酸
化アルミニウムの粉末中の塩化アルミニウムが、熱加水
分解反応によって酸化アルミニウムと塩酸に容易に分解
する。このとき生じる塩化水素酸ガスを除去することに
より、含有塩素量を低減した酸化アルミニウムの粉末を
得ることができる。従ってこの方法によれば、残留塩素
量の少ない高純度、高品質の酸化アルミニウムの粉末を
、簡単に、効率良く速やかに得ることができる。2A I C13+3H20 →A 120i +6HC1 (1) That is, aluminum chloride in the aluminum oxide powder is easily decomposed into aluminum oxide and hydrochloric acid by a thermal hydrolysis reaction. By removing the hydrochloric acid gas generated at this time, aluminum oxide powder with a reduced amount of chlorine content can be obtained. Therefore, according to this method, high purity and high quality aluminum oxide powder with a small amount of residual chlorine can be obtained easily, efficiently and quickly.
また、本発明のガスセンサにおいては、上記方法により
塩素濃度が１１００ｐｐ以下に低減された酸化アルミニ
ウムが触媒層の担体として用いられているので、塩素に
よるアルミナ担体上の触媒の機能、使用寿命の低下が防
止される。その上に、塩素によるガス感応体の感度低下
が防止されるので、ガスセンサの感度、選択性の低下が
防止される。また、塩素によるガスセンサの電極や電気
回路の配線部分等の腐食が防止されるので、ガスセンサ
の品質、信頼性を向上させることができる。In addition, in the gas sensor of the present invention, aluminum oxide whose chlorine concentration has been reduced to 1100 pp or less by the above method is used as a support for the catalyst layer, so that the function and service life of the catalyst on the alumina support due to chlorine are not reduced. Prevented. Furthermore, since deterioration in the sensitivity of the gas sensitive body due to chlorine is prevented, deterioration in the sensitivity and selectivity of the gas sensor is prevented. Further, since corrosion of the electrodes of the gas sensor, the wiring parts of the electric circuit, etc. due to chlorine is prevented, the quality and reliability of the gas sensor can be improved.
（実施例） 以下に、本発明の実施例について図を用いて説明する。(Example) Embodiments of the present invention will be described below with reference to the drawings.
第１図は本発明の一実施例の酸化アルミニウム中の塩素
除去方法において用いる装置の構成を示す断面図である
。図において、この塩素除去装置１は、概略塩素を含有
する酸化アルミニウムの粉末Ａを収容する反応室２と、
反応室２を加熱する加熱手段３と、反応室２内に水蒸気
を供給する水蒸気供給手段４とから成る。反応室２は、
各種のセラミックス等の材料から成る反応炉５の内部に
設けられた適宜な容積の空間部分である。反応室２には
、酸化アルミニウムの粉末Ａを収納するだめのセラミッ
クス製容器６が配置される。反応炉５の炉壁の一部には
水蒸気を室内に流入させるための給水口５ａが形成され
ており、給水口５ａに対向する炉壁の上部には、反応室
２内における反応後の未反応水蒸気や塩化水素酸等の排
気ガスを室外へ排出させるための排気口５ｂが形成され
ている。FIG. 1 is a sectional view showing the configuration of an apparatus used in a method for removing chlorine from aluminum oxide according to an embodiment of the present invention. In the figure, this chlorine removal apparatus 1 includes a reaction chamber 2 containing aluminum oxide powder A containing approximately chlorine;
It consists of a heating means 3 for heating the reaction chamber 2 and a steam supply means 4 for supplying water vapor into the reaction chamber 2. The reaction chamber 2 is
It is a space portion of an appropriate volume provided inside a reactor 5 made of various materials such as ceramics. In the reaction chamber 2, a ceramic container 6 for storing aluminum oxide powder A is arranged. A water inlet 5a is formed in a part of the reactor wall of the reactor 5 to allow water vapor to flow into the chamber, and an upper part of the reactor wall opposite to the water inlet 5a is provided with a water inlet 5a for allowing water vapor to flow into the chamber after the reaction in the reaction chamber 2. An exhaust port 5b is formed for exhausting exhaust gases such as reaction steam and hydrochloric acid to the outside.
加熱手段３としては、例えば電熱ヒータや、水蒸気によ
り加熱を行う水蒸気加熱器、高周波による加熱を行う高
周波加熱器等が挙げられる。このような加熱手段３が、
反応炉５の炉壁や炉底等の適宜な部位に配設されている
。Examples of the heating means 3 include an electric heater, a steam heater that heats with water vapor, and a high frequency heater that heats with high frequency. Such a heating means 3 is
It is arranged at an appropriate location such as the furnace wall or the furnace bottom of the reactor 5.
水蒸気供給手段４は、水が収容された水容器７と、水容
器７を加熱して水蒸気を発生させるためのヒータ８と、
空気を水容器７内に送り込むための空気送入ポンプ９及
び空気送入管１０と、水容器７から発生する水蒸気を反
応室２内に送り込むための水蒸気送入管１１とから成る
。水蒸気送入管１１は、反応炉５の給水口５ａから反応
室２内に挿入され、その挿入部分が反応室２内の容器６
の直上に配置されている。この水蒸気送入管１１におけ
る容器６の直上部分、すなわち容器６内の酸化アルミニ
ウムの粉末Ａの直上部分は網目状に形成され、ここから
水蒸気が酸化アルミニウムの粉末Ａに噴霧されるように
なっている。The water vapor supply means 4 includes a water container 7 containing water, a heater 8 for heating the water container 7 and generating water vapor,
It consists of an air feed pump 9 and an air feed pipe 10 for sending air into the water container 7, and a steam feed pipe 11 for sending water vapor generated from the water container 7 into the reaction chamber 2. The steam feed pipe 11 is inserted into the reaction chamber 2 from the water supply port 5a of the reactor 5, and the inserted portion is connected to the container 6 in the reaction chamber 2.
is placed directly above. The portion of the steam supply pipe 11 directly above the container 6, that is, the portion directly above the aluminum oxide powder A in the container 6, is formed into a mesh shape, from which water vapor is sprayed onto the aluminum oxide powder A. There is.
また、反応炉の排気口５ｂには、排気ガスを反応室２外
へ排出させるための排気管１２が設ケラれており、排気
管１２は排気ポンプ等の不図示のガス排気機器に接続さ
れている。Further, an exhaust pipe 12 for discharging exhaust gas to the outside of the reaction chamber 2 is installed at the exhaust port 5b of the reactor, and the exhaust pipe 12 is connected to a gas exhaust device (not shown) such as an exhaust pump. ing.
この装置を運転するにあたり、容器６内に収納する酸化
アルミニウムの粉末Ａは、前記した従来方法により製造
されたものでよい。すなわち、塩化物、硝酸塩、硫酸塩
等のアルミニウム溶液を加水分解して水酸化アルミニウ
ムを生成し、これを熱処理して得られる酸化アルミニウ
ムを粉砕等により微細化して粉末状とする。この酸化ア
ルミニウムの粉末Ａの粒子径は、酸化アルミニウムと水
蒸気との接触面積を大きくして加水分解反応を速やかに
進行させるために、１００ＯＡ以下とすることが好まし
く、５００Å以下とすることがより好ましい。In operating this apparatus, the aluminum oxide powder A stored in the container 6 may be produced by the conventional method described above. That is, an aluminum solution of chloride, nitrate, sulfate, etc. is hydrolyzed to produce aluminum hydroxide, and the resulting aluminum oxide is pulverized by pulverization or the like to form a powder. The particle size of this aluminum oxide powder A is preferably 100 OA or less, and more preferably 500 Å or less, in order to increase the contact area between aluminum oxide and water vapor and cause the hydrolysis reaction to proceed quickly. .
上記装置を用いて酸化アルミニウム中の塩素除去を行う
際には、塩素を含有する酸化アルミニウムの粉末Ａを反
応室２内に配置される容器６内に収容し、加熱手段３に
より反応室２を２５０〜６００℃、より好ましくは４０
０〜５００℃に加熱する。一方、ヒータ８により水容器
７を加熱して、温度７０℃以上、より好ましくは９０℃
以上の水蒸気を水容器７から発生させながら、空気送入
ポンプ９、空気送入管１０により空気を水容器７内に送
り込む。それにより水蒸気が水蒸気送入管１１を介して
、反応室２内の酸化アルミニウムの粉末Ａ上に供給され
る。When removing chlorine from aluminum oxide using the above device, aluminum oxide powder A containing chlorine is placed in a container 6 placed in the reaction chamber 2, and the reaction chamber 2 is heated by the heating means 3. 250-600℃, more preferably 40
Heat to 0-500°C. On the other hand, the water container 7 is heated by the heater 8 to a temperature of 70°C or more, preferably 90°C.
While generating the above water vapor from the water container 7, air is sent into the water container 7 by the air feed pump 9 and the air feed pipe 10. Thereby, water vapor is supplied via the water vapor inlet pipe 11 onto the aluminum oxide powder A in the reaction chamber 2 .
水蒸気が与えられた酸化アルミニウムの粉末Ａにおいて
は、前記（１）式に示した熱加水分ｌ１ｌｑ反応が生じ
、塩化アルミニウムが酸化アルミニウムと塩酸に分解す
る。反応後に生じる未反応水蒸気や塩化水素酸等の排気
ガスは、排気管１２から速やかに装置外部に排出される
。それによって、酸化アルミニウムの粉末Ａ中の残留塩
素が除去され、純度の高い酸化アルミニウムの粉末を得
ることができる。In aluminum oxide powder A to which water vapor has been applied, the thermal hydrolysis l1lq reaction shown in equation (1) occurs, and aluminum chloride is decomposed into aluminum oxide and hydrochloric acid. Exhaust gases such as unreacted water vapor and hydrochloric acid generated after the reaction are quickly discharged to the outside of the apparatus from the exhaust pipe 12. As a result, residual chlorine in the aluminum oxide powder A is removed, and highly pure aluminum oxide powder can be obtained.
実験例
上記塩素除去装置１において、前述した従来の製法によ
り得られた塩素濃度１１００００ｐｐの酸化アルミニウ
ムの粉末１０ｋｇを容器６内に収容し、温度９０℃の水
蒸気を４００１／ｍｉｎの流量で反応室２内に流し込み
ながら、反応室２を４００℃で１２０分間加熱した。こ
の後、反応後の酸化アルミニウムの粉末に対して、熱加
水分解−イオンクロマトグラフ法により塩素の定量を行
ったところ、塩素濃度は１０ｐｐｍであった。すなわち
、従来法により製造された酸化アルミニウム中の残留塩
素を１／１０００に低減することができた。 ところで
、この方法において、加水分解温度３００℃、４００℃
、６００℃の場合の熱加水分解時間と酸化アルミニウム
中の塩素濃度との関係を調べたところ、それぞれ第２図
、第３図、第４図に示す通りであった。図中白点は水蒸
気を供給しながら酸化アルミニウムの粉末を加熱した場
合のデータ、黒点は水蒸気を供給せずに酸化アルミニウ
ムの粉末を加熱した場合のデータを示す。Experimental Example In the above chlorine removal apparatus 1, 10 kg of aluminum oxide powder with a chlorine concentration of 110,000 pp obtained by the conventional manufacturing method described above was placed in the container 6, and steam at a temperature of 90° C. was introduced into the reaction chamber 2 at a flow rate of 4001/min. The reaction chamber 2 was heated at 400° C. for 120 minutes while pouring the mixture into the reactor. Thereafter, the amount of chlorine in the aluminum oxide powder after the reaction was determined by thermal hydrolysis-ion chromatography, and the chlorine concentration was 10 ppm. That is, the residual chlorine in aluminum oxide produced by the conventional method could be reduced to 1/1000. By the way, in this method, the hydrolysis temperature is 300°C, 400°C.
The relationship between the thermal hydrolysis time and the chlorine concentration in aluminum oxide at 600° C. was investigated, and the results were as shown in FIGS. 2, 3, and 4, respectively. In the figure, white dots indicate data when aluminum oxide powder is heated while supplying water vapor, and black dots indicate data when aluminum oxide powder is heated without supplying water vapor.
図かられかるように、温度４００℃の場合に塩素濃度の
減少速度が最も大きく、すなわち熱加水分解反応が速や
かに進行して、効率良く酸化アルミニウム中の塩素が除
去される。一方、温度３００℃の場合には、４００℃の
場合に比べて熱加水分解反応の速度が遅く、塩素除去効
率が悪い。温度６００℃の場合には、熱加水分解反応の
速度は３００℃の場合に比べて比較的速く、塩素除去効
率は良いが、反応中に酸化アルミニウムの結晶粒子の成
長が促進され、その結果粉砕等により微細化した際の酸
化アルミニウムの純度が悪くなるので、温度４００℃の
場合に比べてあまり好ましくない。As can be seen from the figure, when the temperature is 400° C., the rate of decrease in chlorine concentration is the greatest, that is, the thermal hydrolysis reaction proceeds rapidly, and chlorine in aluminum oxide is efficiently removed. On the other hand, when the temperature is 300°C, the rate of thermal hydrolysis reaction is slower than when the temperature is 400°C, and the chlorine removal efficiency is poor. At a temperature of 600°C, the rate of thermal hydrolysis reaction is relatively faster than at 300°C, and the chlorine removal efficiency is good, but the growth of aluminum oxide crystal particles is promoted during the reaction, resulting in pulverization. Since the purity of aluminum oxide deteriorates when the aluminum oxide is refined by the above methods, it is less preferable than the case where the temperature is 400°C.
上記したように、本発明方法によれば、残留塩素量が少
ない高純度、高品質の酸化アルミニウムを、低コストで
簡単に、効率良く速やかに得ることができる。この酸化
アルミニウムを用いれば、触媒担体、ガスセンサ、蛍光
体、ＹＡＧレーザ素子、磁性体担体、透光性セラミック
ス等の電子機能材料やファインセラミックス等の構造材
料の塩素による腐食や機能低下を防止して、材料の品質
を向上させることができる。As described above, according to the method of the present invention, high purity and high quality aluminum oxide with a small amount of residual chlorine can be obtained easily, efficiently and quickly at low cost. By using this aluminum oxide, it is possible to prevent corrosion and functional deterioration due to chlorine in electronic functional materials such as catalyst carriers, gas sensors, phosphors, YAG laser elements, magnetic carriers, translucent ceramics, and structural materials such as fine ceramics. , material quality can be improved.
第５図は本発明の一実施例のガスセンサの構成を示す断
面図、第６図は同実施例のガスセンサがビン足止に取付
けられた状態を示す斜視図である。FIG. 5 is a sectional view showing the configuration of a gas sensor according to an embodiment of the present invention, and FIG. 6 is a perspective view showing the gas sensor according to the embodiment attached to a bottle stopper.
図において、このガスセンサ２０は、筒状絶縁基体２１
の外周面上に１対の電極２２が設けられ、絶縁基体２１
及び電極２２を被覆するように金属酸化物半導体から成
る層２３が設けられており、この層がガス感応体として
機能する。このガス感応体２３の表面には触媒層２４が
設けられており、触媒層２４はＶ、Ｒｈ、Ｐｄ、Ｐｔ、
Ａｕ等の貴金属が担体に担持されて成る。In the figure, this gas sensor 20 has a cylindrical insulating base 21
A pair of electrodes 22 are provided on the outer peripheral surface of the insulating base 21.
A layer 23 made of a metal oxide semiconductor is provided to cover the electrode 22, and this layer functions as a gas sensitive body. A catalyst layer 24 is provided on the surface of this gas sensitive body 23, and the catalyst layer 24 includes V, Rh, Pd, Pt,
A noble metal such as Au is supported on a carrier.
触媒層２４の担体は、前記塩素除去方法により残留塩素
濃度が１１００ｐｐ以下に低減された酸化アルミニウム
から成る。このように構成されたガスセンサ２０は、例
えば第６図に示すようにピン足止に他と接触しない状態
で取付けられ、保持される。第６図中２５は電極用リー
ド線、２６は絶縁板、２７はヒータを示す。ヒータ２７
は、ガス感応体２３を約４５０℃前後に加熱できるよう
になっており、ガスセンサ２０の感度を向上させるため
に設けられたものである。 本実施例のガスセンサにお
いては、上記したように残留塩素濃度が１１００ｐｐ以
下に低減された酸化アルミニウムが触媒担体として用い
られている。ここで、従来の酸化アルミニウムは通常的
１１０００ｐｐ〜ｌｖｔ％の塩素を含有しており、これ
に比べて塩素濃度が１１００ｐｐ以下の酸化アルミニウ
ムを用いた場合には、ガスセンサ２０において酸化アル
ミニウム中の塩素がアルミナ担体上の触媒の機能低下、
ガス感応体２３の感度低下、電極２２やリード線２５の
腐食を招くことは少ない。従って、従来に比べてアルミ
ナ担体上の触媒の使用寿命が延長し、ガスセンサ２０の
感度が安定し選択性の低下が防止される。また、電極２
２やリード線２５の腐食が抑制されるので、ガスセンサ
２０の信頼性を向上させることができる。The carrier of the catalyst layer 24 is made of aluminum oxide whose residual chlorine concentration has been reduced to 1100 pp or less by the chlorine removal method described above. The gas sensor 20 configured in this way is mounted and held on a pin stop in a state where it does not come into contact with anything else, for example, as shown in FIG. In FIG. 6, 25 represents an electrode lead wire, 26 represents an insulating plate, and 27 represents a heater. Heater 27
is capable of heating the gas sensitive body 23 to around 450° C., and is provided to improve the sensitivity of the gas sensor 20. In the gas sensor of this example, aluminum oxide whose residual chlorine concentration has been reduced to 1100 pp or less as described above is used as a catalyst carrier. Here, conventional aluminum oxide usually contains chlorine of 11,000 pp to lvt%, and compared to this, when aluminum oxide with a chlorine concentration of 1,100 pp or less is used, the chlorine in the aluminum oxide in the gas sensor 20 is Decreased functionality of the catalyst on the alumina support,
A decrease in the sensitivity of the gas sensitive body 23 and corrosion of the electrodes 22 and lead wires 25 are unlikely to occur. Therefore, the service life of the catalyst on the alumina carrier is extended compared to the conventional one, the sensitivity of the gas sensor 20 is stabilized, and a decrease in selectivity is prevented. In addition, electrode 2
Since corrosion of the gas sensor 2 and the lead wire 25 is suppressed, the reliability of the gas sensor 20 can be improved.
以上本発明の実施例について説明したが、本発明はこれ
に限定されるものではなく、種々変形実施が可能である
。Although the embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made.
［発明の効果］
本発明は以上の構成及び作用を有するもので、本発明の
酸化アルミニウム中の塩素除去方法によれば、残留塩素
が少ない高純度、高品質の酸化アルミニウムを、低コス
ト、高効率で、簡便かつ迅速に製造することができ、そ
の工業的価値は極めて大である。[Effects of the Invention] The present invention has the above-described structure and operation. According to the method for removing chlorine from aluminum oxide of the present invention, high purity and high quality aluminum oxide with little residual chlorine can be produced at low cost and at high cost. It can be produced efficiently, easily and quickly, and its industrial value is extremely large.
また、本発明のガスセンサにおいては、塩素による触媒
の機能低下やガス感応体の感度低下が防止され使用寿命
が延長し、ガスセンサの感度や選択性の低下が防止され
て、品質が向上する。さらに、塩素によるガスセンサの
電極や電気回路の配線部分等の腐食が防止されるので、
ガスセンサの信頼性が向上する。。In addition, in the gas sensor of the present invention, deterioration in the function of the catalyst and deterioration in the sensitivity of the gas sensitive body due to chlorine is prevented, the service life is extended, and deterioration in the sensitivity and selectivity of the gas sensor is prevented, resulting in improved quality. Furthermore, corrosion of gas sensor electrodes and electrical circuit wiring parts caused by chlorine is prevented.
The reliability of the gas sensor is improved. .
第１図は本発明の一実施例の酸化アルミニウム中の塩素
除去方法において用いる装置の構成を示す断面図、第２
図、第３図、第４図はそれぞれ同実施例において加水分
解温度が３００℃、４００℃、６００℃の場合の熱加水
分解時間と酸化アルミニウム中の塩素濃度との関係を示
す図、第５図は本発明の一実施例のガスセンサの構成を
示す断面図、第６図は同実施例のガスセンサがピン足止
に取付けられた状態を示す斜視図である。
１・・・塩素除去装置
２・・・反応室
３・・・加熱手段
４・・・水蒸気供給手段
２０・・・ガスセンサ
２３・・・ガス感応体
２４・・・触媒層
Ａ・・・酸化アルミニウムの粉末FIG. 1 is a sectional view showing the configuration of an apparatus used in a method for removing chlorine from aluminum oxide according to an embodiment of the present invention, and FIG.
Figures 3 and 4 are diagrams showing the relationship between thermal hydrolysis time and chlorine concentration in aluminum oxide when the hydrolysis temperatures were 300°C, 400°C, and 600°C in the same example, respectively. FIG. 6 is a sectional view showing the configuration of a gas sensor according to an embodiment of the present invention, and FIG. 6 is a perspective view showing the gas sensor according to the embodiment attached to a pin stop. 1... Chlorine removal device 2... Reaction chamber 3... Heating means 4... Steam supply means 20... Gas sensor 23... Gas sensitive body 24... Catalyst layer A... Aluminum oxide powder of
Claims (2)
給しながら該粉末を加熱し、加水分解により生じた排気
ガスを取り除くことによって該粉末から塩素を除去する
ことを特徴とする酸化アルミニウム中の塩素除去方法。(1) Chlorine in aluminum oxide, characterized in that chlorine is removed from aluminum oxide powder containing chlorine by heating the powder while supplying steam and removing exhaust gas generated by hydrolysis. Removal method.
体の表面に設けられたガスセンサにおいて、 前記担体が、請求項１に記載の方法で製造され塩素濃度
が１００ｐｐｍ以下とされた酸化アルミニウムから成る
ことを特徴とするガスセンサ。(2) A gas sensor in which a catalyst layer in which a precious metal is supported on a carrier is provided on the surface of a gas sensitive member, wherein the carrier is aluminum oxide manufactured by the method according to claim 1 and having a chlorine concentration of 100 ppm or less. A gas sensor characterized by comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32258790A JPH04198014A (en) | 1990-11-28 | 1990-11-28 | Removal of chlorine in aluminum oxide and gas sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32258790A JPH04198014A (en) | 1990-11-28 | 1990-11-28 | Removal of chlorine in aluminum oxide and gas sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04198014A true JPH04198014A (en) | 1992-07-17 |
Family
ID=18145363
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32258790A Pending JPH04198014A (en) | 1990-11-28 | 1990-11-28 | Removal of chlorine in aluminum oxide and gas sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04198014A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6162413A (en) * | 1995-02-21 | 2000-12-19 | Sumitomo Chemical Company, Limited | Alpha-alumina and method for producing same |
| US6524549B1 (en) | 1993-11-25 | 2003-02-25 | Sumitomo Chemical Co., Ltd. | Method for producing α-alumina powder |
-
1990
- 1990-11-28 JP JP32258790A patent/JPH04198014A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6524549B1 (en) | 1993-11-25 | 2003-02-25 | Sumitomo Chemical Co., Ltd. | Method for producing α-alumina powder |
| US6162413A (en) * | 1995-02-21 | 2000-12-19 | Sumitomo Chemical Company, Limited | Alpha-alumina and method for producing same |
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