JP5020136B2 - Fluorine fixing agent, PFC decomposition treatment agent, and preparation method thereof - Google Patents
Fluorine fixing agent, PFC decomposition treatment agent, and preparation method thereof Download PDFInfo
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- 229910052731 fluorine Inorganic materials 0.000 title claims description 132
- 239000011737 fluorine Substances 0.000 title claims description 131
- 239000003795 chemical substances by application Substances 0.000 title claims description 130
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 title claims description 129
- 238000000354 decomposition reaction Methods 0.000 title claims description 46
- 238000002360 preparation method Methods 0.000 title description 7
- 239000007789 gas Substances 0.000 claims description 96
- 239000002245 particle Substances 0.000 claims description 44
- 239000000203 mixture Substances 0.000 claims description 41
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 40
- 238000000034 method Methods 0.000 claims description 40
- 238000010304 firing Methods 0.000 claims description 36
- 150000001875 compounds Chemical class 0.000 claims description 31
- 229910052757 nitrogen Inorganic materials 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- -1 perfluoro compound Chemical class 0.000 claims description 17
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 11
- 230000001590 oxidative effect Effects 0.000 claims description 9
- 239000002131 composite material Substances 0.000 claims description 5
- 239000000446 fuel Substances 0.000 claims description 4
- 238000002485 combustion reaction Methods 0.000 claims description 3
- 230000006872 improvement Effects 0.000 claims description 2
- 229910052763 palladium Inorganic materials 0.000 claims description 2
- 229910052697 platinum Inorganic materials 0.000 claims description 2
- 229910052703 rhodium Inorganic materials 0.000 claims description 2
- 229910052707 ruthenium Inorganic materials 0.000 claims description 2
- MXRIRQGCELJRSN-UHFFFAOYSA-N O.O.O.[Al] Chemical compound O.O.O.[Al] MXRIRQGCELJRSN-UHFFFAOYSA-N 0.000 claims 1
- 239000002671 adjuvant Substances 0.000 claims 1
- 238000001354 calcination Methods 0.000 claims 1
- TXEYQDLBPFQVAA-UHFFFAOYSA-N tetrafluoromethane Chemical compound FC(F)(F)F TXEYQDLBPFQVAA-UHFFFAOYSA-N 0.000 description 61
- 239000011575 calcium Substances 0.000 description 52
- 238000012545 processing Methods 0.000 description 25
- 238000002441 X-ray diffraction Methods 0.000 description 22
- 230000000694 effects Effects 0.000 description 12
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 10
- 239000004065 semiconductor Substances 0.000 description 9
- 239000010410 layer Substances 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000002156 mixing Methods 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 238000006297 dehydration reaction Methods 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 230000018044 dehydration Effects 0.000 description 6
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminum fluoride Inorganic materials F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 description 5
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 238000001179 sorption measurement Methods 0.000 description 5
- IRPGOXJVTQTAAN-UHFFFAOYSA-N 2,2,3,3,3-pentafluoropropanal Chemical compound FC(F)(F)C(F)(F)C=O IRPGOXJVTQTAAN-UHFFFAOYSA-N 0.000 description 4
- 229910004261 CaF 2 Inorganic materials 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- 238000002425 crystallisation Methods 0.000 description 4
- 230000008025 crystallization Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 239000003513 alkali Substances 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 238000007873 sieving Methods 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 2
- 229910001634 calcium fluoride Inorganic materials 0.000 description 2
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 2
- 239000000920 calcium hydroxide Substances 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 238000005108 dry cleaning Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 239000000834 fixative Substances 0.000 description 2
- 150000002221 fluorine Chemical class 0.000 description 2
- 150000002222 fluorine compounds Chemical class 0.000 description 2
- 239000010436 fluorite Substances 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 2
- 238000001027 hydrothermal synthesis Methods 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910003691 SiBr Inorganic materials 0.000 description 1
- 229910003902 SiCl 4 Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001341 alkaline earth metal compounds Chemical class 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical compound FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910000042 hydrogen bromide Inorganic materials 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- SFZCNBIFKDRMGX-UHFFFAOYSA-N sulfur hexafluoride Chemical compound FS(F)(F)(F)(F)F SFZCNBIFKDRMGX-UHFFFAOYSA-N 0.000 description 1
- 229960000909 sulfur hexafluoride Drugs 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 238000002076 thermal analysis method Methods 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/30—Capture or disposal of greenhouse gases of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6]
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- Treating Waste Gases (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Description
本発明は、フッ素含有化合物を含むガスの処理に関する。特に、本発明は、半導体工業において半導体製造装置の内面等をドライクリーニングする工程や、酸化膜等の各種成膜をエッチングする工程から排出されるフッ素含有化合物、特にパーフルオロ化合物（ＰＦＣ）を含む排ガスを処理して、フッ素を回収するフッ素固定剤及びその調製方法並びにフッ素固定方法に関する。また、本発明は、ＰＦＣガス含有ガスを処理する際に用いるＰＦＣ分解処理剤及びその調製方法並びにフッ素含有化合物の処理方法に関する。 The present invention relates to the treatment of gases containing fluorine-containing compounds. In particular, the present invention includes a fluorine-containing compound, particularly a perfluoro compound (PFC) discharged from a step of dry cleaning the inner surface of a semiconductor manufacturing apparatus in the semiconductor industry and a step of etching various film formation such as an oxide film. The present invention relates to a fluorine fixing agent for treating exhaust gas and recovering fluorine, a method for preparing the same, and a fluorine fixing method. The present invention also relates to a PFC decomposition treatment agent used when treating a PFC gas-containing gas, a method for preparing the same, and a method for treating a fluorine-containing compound.
半導体工業においては、半導体製造工程中に多種類の有害ガスが使用されており、環境中への排気による環境汚染が懸念される。特に、半導体工業における半導体製造装置内面のクリーニング工程や、エッチング工程或いはＣＶＤ工程などにおいては、CHF3などのフッ化炭化水素や、CF4、C2F6、C3F8、C4F6、C4F8、C5F8、SF6、NF3などのパーフルオロ化合物（ＰＦＣ）などのフッ素含有化合物が用いられており、これらのプロセスからの排ガス中に含まれるフッ素含有化合物は、地球温暖化ガスとしてその除去システムの確立が急務とされている。 In the semiconductor industry, many kinds of harmful gases are used during the semiconductor manufacturing process, and there is a concern about environmental pollution due to exhaust into the environment. In particular, in the semiconductor manufacturing equipment cleaning process, etching process or CVD process in the semiconductor industry, fluorinated hydrocarbons such as CHF 3 , CF 4 , C 2 F 6 , C 3 F 8 , C 4 F 6 , Fluorine-containing compounds such as perfluoro compounds (PFC) such as C 4 F 8 , C 5 F 8 , SF 6 and NF 3 are used, and fluorine-containing compounds contained in exhaust gas from these processes are As a global warming gas, it is urgently required to establish a removal system.
フッ素含有化合物を含む排ガスの処理方法としては、例えば、酸化アルミニウム及びアルカリ土類金属の酸化物を含む処理剤を用いて排ガス中のフルオロカーボンを分解処理する方法（特許文献１）；酸化アルミニウム及びアルカリ土類金属の酸化物を含む処理剤を用いて排ガス中のフッ化硫黄を分解処理する方法（特許文献２）；アルミナ及びアルカリ土類金属化合物、及び場合によっては銅、錫、バナジウム等の金属の酸化物を含む処理剤を用いて排ガス中のフッ素化合物を分解処理する方法（特許文献３）；水酸化アルミニウムと水酸化カルシウムとを含む処理剤を用いて排ガス中のＰＦＣを分解処理する方法（特許文献４）；などが提案されている。 As a method for treating exhaust gas containing a fluorine-containing compound, for example, a method of decomposing fluorocarbon in exhaust gas using a treatment agent containing aluminum oxide and an oxide of an alkaline earth metal (Patent Document 1); aluminum oxide and alkali A method of decomposing sulfur fluoride in exhaust gas using a treating agent containing an earth metal oxide (Patent Document 2); alumina and alkaline earth metal compounds, and in some cases metals such as copper, tin, vanadium, etc. Method for Decomposing Fluorine Compound in Exhaust Gas Using Treatment Agent Containing Oxide (Patent Document 3); Method for Decomposing PFC in Exhaust Gas Using Treatment Agent Containing Aluminum Hydroxide and Calcium Hydroxide (Patent Document 4); and the like have been proposed.
しかしながら、上記のような従来の処理方法は、処理温度が８００〜１０００℃と高いため、処理装置の熱による劣化が速く、装置のエネルギー消費量も大きいという問題があった。また、従来の処理剤は、使用寿命が短くて交換頻度が高いという問題を包含していた。例えば、特許文献１〜３に開示されている方法では、ＰＦＣを酸化アルミニウム（アルミナ）と反応させてフッ化アルミニウムを生成させることによってＰＦＣガスを分解している。しかしながら、酸化アルミニウムの反応活性が低いので、この反応を効率よく進行させるためには、高温の反応条件が必要である。更に、生成したフッ化アルミニウムが酸化アルミニウムの表面に層を形成し、これによって酸化アルミニウムが被毒されて短時間で触媒活性を失うために、処理剤の交換頻度が高くなってしまうという問題がある。
However, the conventional processing method as described above has a problem that the processing temperature is as high as 800 to 1000 ° C., so that the processing apparatus is rapidly deteriorated by heat and the energy consumption of the apparatus is large. Moreover, the conventional processing agent included the problem that service life is short and replacement frequency is high. For example, in the methods disclosed in
ＰＦＣガスを水酸化アルミニウムと反応させて、水酸化アルミニウムの水酸基の水素によってフッ素をフッ化水素とし、次に生成したフッ化水素を水酸化カルシウムと反応させてフッ化カルシウムを生成させることによって、ＰＦＣガスなどのフッ素含有化合物を従来法よりも低い温度で効率よく分解処理することができる方法が提案されている（特許文献４）。しかし、かかる方法は、小型の装置では効果があるものの、実機規模にスケールアップすると、アルミニウムの活性が阻害され、十分な除去効果を示さない場合があることが確認された。 PFC gas is reacted with aluminum hydroxide, fluorine is converted to hydrogen fluoride with hydrogen of the hydroxyl group of aluminum hydroxide, and then the generated hydrogen fluoride is reacted with calcium hydroxide to generate calcium fluoride. A method that can efficiently decompose a fluorine-containing compound such as PFC gas at a temperature lower than that of the conventional method has been proposed (Patent Document 4). However, although this method is effective in a small apparatus, it has been confirmed that when it is scaled up to an actual scale, the activity of aluminum is inhibited and a sufficient removal effect may not be exhibited.
更に、近年、フッ素の原料となる蛍石の資源枯渇が問題となっており、フッ素の回収・再利用が重要な課題となっているが、ＰＦＣガスを分解してフッ化アルミニウムを生成させる場合、フッ化アルミニウムは水にも酸にもアルカリにも溶解しない化合物であるため、フッ化アルミニウムからフッ素を回収するのは、コスト的、技術的に難しい。
そこで、本発明の目的は、かかる従来技術の課題を解決し、スケールアップした実機でも失活せずにＰＦＣガスを効率よく分解し、分解した生成物からフッ素を効率よく回収して再利用に供することのできるフッ素固定剤、その調製方法及びフッ素固定方法を提供することにある。 Therefore, the object of the present invention is to solve the problems of the prior art, efficiently decompose PFC gas without deactivation even with a scaled-up actual machine, and efficiently recover fluorine from the decomposed product for reuse. It is providing the fluorine fixing agent which can be provided, the preparation method, and the fluorine fixing method.
別の目的は、スケールアップした実機でも失活せずにＰＦＣガスを効率よく分解することができ、耐久性に優れたＰＦＣ分解処理剤及びその調製方法並びにＰＦＣガス含有排ガスの処理方法を提供することにある。 Another object is to provide a PFC decomposition treatment agent that is capable of efficiently decomposing PFC gas without being deactivated even with a scaled-up actual machine, a method for preparing the same, and a method for treating exhaust gas containing PFC gas. There is.
本発明者らは、上記の課題を解決するべく鋭意研究を重ねた結果、特に特許文献４に記載の方法をスケールアップした実機に適用した場合、加熱によって装置内に発生する水分が蒸発せず水分過剰の状態になって、酸化アルミニウムがα化（結晶化）してアルミニウムの活性が低下すること（活性点での微細構造の変化、例えば、OH基が活性点に吸着することによる変質や活性点での局所的なα化が進み、不活性化すること）を確認し、焼成時に水分過剰の状態を回避して結晶化を阻止することでアルミニウムの活性を高く維持したフッ素固定剤及びＰＦＣ処理剤を得ることができることを見出し、本発明を完成するに至った。
As a result of intensive studies to solve the above-described problems, the present inventors have not evaporated the water generated in the apparatus by heating, particularly when the method described in
本発明によれば、平均粒子径（メディアン径）６０μｍ以上１６０μｍ以下のAl(OH)3
と、Ca(OH)2とのモル比が３：７〜５：５である混合物を４３０℃よりも高く８９０℃以
下の温度範囲で、窒素流又は空気流中で焼成することを特徴とするフッ素固定剤又はＰＦＣ（パーフルオロ化合物）分解処理剤の調製方法及び当該調製方法により得られるフッ素固定剤又はＰＦＣ（パーフルオロ化合物）分解処理剤が提供される。また、本発明によれば、平均粒子径（メディアン径）５５μｍ以上１６０μｍ以下のAl(OH)3と、Ca(OH)2とのモル比が３：７〜５：５である混合物を４３０℃よりも高く８９０℃以下の温度範囲で、窒素流又は空気流中で焼成することを特徴とするフッ素固定剤又はＰＦＣ（パーフルオロ化合物）分解処理剤の調製方法及び当該調製方法により得られるフッ素固定剤又はＰＦＣ（パーフルオロ化合物）分解処理剤が提供される。本発明のフッ素固定剤及びＰＦＣ分解処理剤はフッ素含有化合物を含む被処理ガスの処理に用いられる。なお、本願明細書において「ＰＦＣ分解処理」と「フッ素固定」とは、前者がＰＦＣ分解処理までを意味し、後者がさらにフッ素をCaF2などの固形物として回収することまでを包含する概念として使い分ける。ただし、「ＰＦＣ分解処理剤」と「フッ素固定剤」との構成成分としては同一であるので、以後の説明では両者を特に使い分けず、「フッ素固定剤」との表現には「ＰＦＣ分解処理剤」を包含させる。
According to the present invention, Al (OH) 3 having an average particle diameter (median diameter) of 60 μm to 160 μm.
And a Ca (OH) 2 molar ratio of 3: 7 to 5: 5 is calcined in a nitrogen flow or air flow in a temperature range higher than 430 ° C. and lower than 890 ° C. Provided are a method for preparing a fluorine fixing agent or a PFC (perfluoro compound ) decomposition treatment agent, and a fluorine fixing agent or a PFC (perfluoro compound ) decomposition treatment agent obtained by the preparation method. Further, according to the present invention, a mixture in which the molar ratio of Al (OH) 3 having an average particle diameter (median diameter) of 55 μm to 160 μm and Ca (OH) 2 is 3: 7 to 5: 5 is 430 ° C. Higher than 890 ° C. in a nitrogen flow or air flow, and a method for preparing a fluorine fixing agent or a PFC (perfluoro compound ) decomposition treatment agent, and a fluorine fixing obtained by the preparation method An agent or a PFC (perfluoro compound ) decomposition treatment agent is provided. The fluorine fixing agent and PFC decomposition treatment agent of the present invention are used for treatment of a gas to be treated containing a fluorine-containing compound. In the specification of the present application, “PFC decomposition treatment” and “fluorine fixation” means that the former means up to the PFC decomposition treatment, and the latter further uses as a concept including recovering fluorine as a solid substance such as
本発明のフッ素固定剤の原材料であるAl(OH)3は、その平均粒子径が５５μｍ以上、好ましくは６０μｍ以上１６０μｍ以下、より好ましくは９０μｍ以上１２０μｍ以下である。ここで、平均粒子径とは、メディアン径を意味し、粒子径ごとに頻度（含有量）を積算し、含有量の累積が最小粒子径からはじめて５０％になる点での粒子径である。 Al (OH) 3 which is a raw material of the fluorine fixing agent of the present invention has an average particle size of 55 μm or more, preferably 60 μm or more and 160 μm or less, more preferably 90 μm or more and 120 μm or less. Here, the average particle diameter means the median diameter, and is the particle diameter at which the frequency (content) is integrated for each particle diameter, and the accumulation of the content reaches 50% from the minimum particle diameter.
平均粒子径が上記範囲外であると、フッ素固定剤としての所望の処理性能が得られず、実施例により後述するように、短時間でCF4除去率が９５％以下に劣化してしまい、実用に耐えない。 If the average particle size is outside the above range, the desired processing performance as a fluorine fixing agent cannot be obtained, and the CF 4 removal rate deteriorates to 95% or less in a short time, as will be described later in Examples. Unbearable for practical use.
本発明のフッ素固定剤の原材料であるCa（OH）2の平均粒子径はAl(OH)3の平均粒径によって変動するが、Al(OH)3よりもCa（OH）2の平均粒子径（メディアン径）は小さい方が好ましい。Ca（OH）2の平均粒子径（メディアン径）としては、好ましくは１μｍ以上１０μｍ以下、より好ましくは３μｍ以上８μｍ以下、最も好ましくは４μｍ以上６μｍ以下である。 The average particle diameter of Ca (OH) 2 that is a raw material of the fluorine fixing agent of the present invention varies depending on the average particle diameter of Al (OH) 3 , but the average particle diameter of Ca (OH) 2 is higher than that of Al (OH) 3. A smaller (median diameter) is preferable. The average particle diameter (median diameter) of Ca (OH) 2 is preferably 1 μm or more and 10 μm or less, more preferably 3 μm or more and 8 μm or less, and most preferably 4 μm or more and 6 μm or less.
Al(OH)3とCa(OH)2とは、平均粒子径の大きいAl(OH)3を核にして、その表層にCa(OH)2が効率よく配置されることで活性が維持されると考えられる。よって、Ca(OH)2の粒径がAl(OH)3の平均粒径に比べて小さすぎるとAl(OH)3の表面全体を隙間なく覆い、ＰＦＣとの接触を阻止して結果的にＰＦＣの分解を阻害し、逆にCa(OH)2の粒径がAl(OH)3の平均粒径に比べて大きすぎるとＰＦＣ分解時のＦとの接触効率が低下し結果的に分解が不充分となり、何れの場合もＰＦＣの分解効率を下げると考えられる。 Al (OH) 3 and Ca (OH) 2 are maintained by the efficient arrangement of Ca (OH) 2 on the surface layer of Al (OH) 3 having a large average particle diameter. it is conceivable that. Thus, Ca (OH) 2 of the particle size is too small compared to the average particle size of Al (OH) 3 Al a (OH) the entire surface of the 3 cover without gaps, consequently by preventing contact between the PFC Inhibiting the decomposition of PFC, conversely, if the Ca (OH) 2 particle size is too large compared to the average particle size of Al (OH) 3 , the contact efficiency with F during PFC decomposition is reduced, resulting in decomposition. In any case, it is considered that the PFC decomposition efficiency is lowered.
上記混合物におけるAl（OH）3とCa（OH）2とのモル比は、３：７〜５：５、好ましくは３：７〜４：６である。Al（OH）3とCa（OH）2とのモル比が上記範囲外であると、ＰＦＣ分解処理剤としての所望の処理性能が得られず、実施例により後述するように、短時間でCF4除去率が９５％以下に劣化してしまい、実用に耐えない。 The molar ratio of Al (OH) 3 and Ca (OH) 2 in the above mixture is 3: 7 to 5: 5, preferably 3: 7 to 4: 6. If the molar ratio of Al (OH) 3 to Ca (OH) 2 is outside the above range, the desired processing performance as a PFC decomposition treatment agent cannot be obtained, and as will be described later in Examples, CF can be obtained in a short time. 4 The removal rate deteriorates to 95% or less, and cannot be practically used.
本発明のフッ素固定剤は、上記混合物を４３０℃よりも高く８９０℃以下の温度範囲、好ましくは５８０℃〜８５０℃、より好ましくは６５０℃〜７８０℃の温度範囲で、窒素流又は空気流中で焼成することにより得られる。 In the fluorine fixing agent of the present invention, the above mixture is heated in a nitrogen stream or an air stream at a temperature range higher than 430 ° C. and lower than or equal to 890 ° C., preferably 580 ° C. to 850 ° C., more preferably 650 ° C. to 780 ° C. It is obtained by firing with
Al（OH）3とCa（OH）2との混合物の焼成温度は、脱水可能な温度であって且つ失活しない温度範囲であることが必要になる。Al（OH）3の脱水温度は約２７０℃であり、Ca（OH）2の脱水温度は約４３０℃であるから、少なくとも４３０℃を超えることが好ましい。温度範囲が８９０℃を超えると、実施例により後述するように、CF4除去率が低下する。このことから、高熱処理により酸化アルミニウムが結晶化してしまい、活性が劣化することによると考えられる。 The firing temperature of the mixture of Al (OH) 3 and Ca (OH) 2 needs to be a temperature that allows dehydration and does not deactivate. Since the dehydration temperature of Al (OH) 3 is about 270 ° C. and the dehydration temperature of Ca (OH) 2 is about 430 ° C., it is preferable to exceed at least 430 ° C. When the temperature range exceeds 890 ° C., the CF 4 removal rate decreases as will be described later in Examples. From this, it is considered that aluminum oxide is crystallized by high heat treatment and the activity deteriorates.
Al（OH）3とCa（OH）2との混合物は、窒素流又は空気流中で焼成する。窒素流又は空気流は一定時間で流入方向を逆転させることが好ましい。焼成により進行する脱水反応の結果、発生する水分を混合物周囲に滞留させず、速やかに蒸発・退去させるためである。高熱高湿雰囲気でAl（OH）3とCa（OH）2との混合物を焼成し続けると、水分の存在により酸化アルミニウムが結晶化（活性点における微細構造レベルでの結晶化を意味する）してしまい、活性が劣化すると考えられる。よって、Al（OH）3や焼成により得られる酸化アルミニウムなどの周囲に不活性ガスを流すことによって、発生する水分を速やかに除去することが必要である。窒素流又は空気流の向流気流は、例えば、Al（OH）3とCa（OH）2との混合物をカラムに充填して、カラムの上下から窒素流又は空気流を送るなどして与えることができる。 A mixture of Al (OH) 3 and Ca (OH) 2 is fired in a stream of nitrogen or air. The flow of nitrogen or air preferably reverses the inflow direction for a certain time. This is because moisture generated as a result of the dehydration reaction that proceeds by firing does not stay around the mixture, but quickly evaporates and leaves. If the mixture of Al (OH) 3 and Ca (OH) 2 is continuously fired in a hot and humid atmosphere, the presence of moisture causes the aluminum oxide to crystallize (meaning crystallization at the fine structure level at the active site). It is thought that the activity deteriorates. Therefore, it is necessary to quickly remove the generated water by flowing an inert gas around Al (OH) 3 or aluminum oxide obtained by firing. The countercurrent airflow of nitrogen flow or air flow is given by, for example, filling a column with a mixture of Al (OH) 3 and Ca (OH) 2 and sending nitrogen flow or air flow from the top and bottom of the column. Can do.
焼成時間は特に限定されず、使用するAl(OH)3とCa(OH)2との量によっても変動するが、一般的に６〜１２時間とするのが脱水効果やエネルギー消費効率の点で好ましく、８〜１０時間とするのがさらに好ましい。技術的にはCa(OH)2が脱水する温度（約４３０℃）まで昇温した後、さらに１〜２時間焼成することで充分であると考えられる。焼成温度に達するまでの昇温速度が速すぎると脱水が不充分な場合が生じ、遅すぎると経済的理由（エネルギーや時間を消費する）から好ましくない。通常は、１００℃／ｈｒの昇温速度が最適である。また、焼成時間が長すぎると、フッ素固定剤が焼成中に燃料から発生するCO2を過吸着してしまい、フッ素吸着性能が低下するので好ましくない。 The firing time is not particularly limited and varies depending on the amount of Al (OH) 3 and Ca (OH) 2 used, but generally 6-12 hours is the point of dehydration effect and energy consumption efficiency. Preferably, the time is 8 to 10 hours. Technically, it is considered sufficient that the temperature is raised to a temperature at which Ca (OH) 2 dehydrates (about 430 ° C.) and then baked for an additional 1-2 hours. If the rate of temperature rise until reaching the firing temperature is too fast, dehydration may be insufficient, and if it is too slow, it is not preferred for economic reasons (consuming energy and time). Usually, a temperature increase rate of 100 ° C./hr is optimum. In addition, if the firing time is too long, the fluorine fixing agent excessively adsorbs CO 2 generated from the fuel during firing, which is not preferable because the fluorine adsorption performance deteriorates.
本発明の調製方法により得られるフッ素固定剤は、後述するＸＲＤ（X線回折）分析により示されるように非晶質Al2O3とCaOとの複合酸化物である。
上記複合酸化物における非晶質Al2O3とCaOとの含有比は、モル比でAl2O3：CaO＝１：１０．５〜１：１２．５であるのが、フッ素固定剤としての活性維持の点で好ましく、１：１０．５〜１：１２であるのが更に好ましい。
The fluorine fixing agent obtained by the preparation method of the present invention is a composite oxide of amorphous Al 2 O 3 and CaO as shown by XRD (X-ray diffraction) analysis described later.
As a fluorine fixing agent, the content ratio of amorphous Al 2 O 3 and CaO in the composite oxide is Al 2 O 3 : CaO = 1: 10.5 to 1: 12.5 in molar ratio. From the standpoint of maintaining the activity, it is preferably 1: 10.5 to 1:12.
また本発明のフッ素固定剤は、その水分含量が５ｗｔ％よりも低いことが好ましく、０．８ｗｔ％以上５ｗｔ％以下であることがより好ましく、１．５ｗｔ％以上３．５ｗｔ％以下であることが最も好ましい。水分含量が高くなると、実施例により後述するように、CF4除去率が低下する。従来、水分含量が高いほどCF4除去率は高くなると考えられており、フッ素含有被処理物の処理時には水分を添加していたことを考え合わせると、本発明のフッ素固定剤において水分含量が少ないほどCF4除去率が高くなるという知見は特異的である。 Further, the fluorine fixing agent of the present invention preferably has a water content lower than 5 wt%, more preferably 0.8 wt% or more and 5 wt% or less, and 1.5 wt% or more and 3.5 wt% or less. Is most preferred. As the water content increases, the CF 4 removal rate decreases as will be described later in Examples. Conventionally, it is believed that the higher the moisture content, the higher the CF 4 removal rate. Considering that moisture was added during the treatment of fluorine-containing workpieces, the moisture content of the fluorine fixing agent of the present invention is low. The finding that the CF 4 removal rate becomes higher is unique.
本発明のフッ素固定剤には、さらに耐熱性向上剤を混合することもできる。耐熱性向上剤としては、ZrO2、Laを好ましく挙げることができる。耐熱性向上剤の配合比率は、好ましくはAl（OH）3１モルに対して０．０１〜０．５モルであり、より好ましくはAl（OH）3１モルに対して０．０５〜０．４モルであり、最も好ましくはAl（OH）3１モルに対して０．０８〜０．３５モルである。耐熱性向上剤の配合比率が上記範囲外であると、その使用温度においてフッ素固定剤の結晶化が徐々に進んで、長期に渡る活性の維持が困難となる。 The fluorine fixing agent of the present invention can be further mixed with a heat resistance improver. Preferable examples of the heat resistance improver include ZrO 2 and La. The blending ratio of the heat resistance improver is preferably 0.01 to 0.5 mol with respect to 1 mol of Al (OH) 3 , more preferably 0.05 to 0 with respect to 1 mol of Al (OH) 3. .4 mole, most preferably 0.08 to 0.35 mole relative to 1 mole of Al (OH) 3 . When the blending ratio of the heat resistance improver is outside the above range, crystallization of the fluorine fixing agent gradually proceeds at the use temperature, and it becomes difficult to maintain the activity over a long period of time.
本発明のフッ素固定剤は、Al(OH)3とCa(OH)2の混合物の焼成品のＮａ含有量が０．０３wt%以下であることが好ましい。Ｎａが多量に存在すると、ＰＦＣ（パーフルオロカーボン）の分解作用を起こす活性点にＮａ＋が選択的に吸着してしまい、ＰＦＣの分解反応を阻害するので好ましくない。 In the fluorine fixing agent of the present invention, the Na content of the baked product of a mixture of Al (OH) 3 and Ca (OH) 2 is preferably 0.03 wt% or less. If Na is present in a large amount, Na + is selectively adsorbed at the active site that causes the PFC (perfluorocarbon) decomposition action, which is not preferable because it inhibits the decomposition reaction of PFC.
本発明のフッ素固定剤には、さらに酸化力向上助剤を混合することもできる。酸化力向上助剤としては、Pd、Pt、Rh、Ruなどを好ましく挙げることができる。酸化力向上助剤の配合割合は、好ましくはAl（OH）3１モルに対して０．００５〜０．１モルであり、より好ましくはAl（OH）3１モルに対して０．０１〜０．０７モルであり、最も好ましくはAl（OH）3１モルに対して０．０２〜０．０５モルである。酸化力向上助剤の配合比率が上記範囲外であると、ＰＦＣのうち炭素数の多いC2F6やC4F8等の分解が進まず、比較的早期に除去性能の低下が始まる。 The fluorine fixing agent of the present invention can be further mixed with an oxidizing power improvement aid. Preferable examples of the oxidizing power improving aid include Pd, Pt, Rh, Ru and the like. The blending ratio of the oxidizing power improving aid is preferably 0.005 to 0.1 mol with respect to 1 mol of Al (OH) 3 , more preferably 0.01 to 1 mol with respect to 1 mol of Al (OH) 3. The amount is 0.07 mol, and most preferably 0.02 to 0.05 mol with respect to 1 mol of Al (OH) 3 . If the blending ratio of the oxidizing power improving aid is outside the above range, decomposition of C 2 F 6 or C 4 F 8 having a large number of carbon atoms in the PFC does not proceed, and the removal performance starts to decrease relatively early.
本発明のフッ素固定剤又はＰＦＣ分解処理剤により処理することのできるフッ素含有化合物としては，CHF3等のフッ化炭化水素、CF4、C2F6、C3F8 などのパーフルオロカーボン
及びSF6、NF3などを含むパーフルオロ化合物（ＰＦＣ）等を挙げることができる。このようなフッ素含有化合物を含むガスとしては、半導体工業で半導体製造装置の内面等をドライクリーニングする工程や、各種成膜をエッチングする工程で排出される排ガスなどを挙げることができる。
Fluorine-containing compounds that can be treated with the fluorine fixing agent or PFC decomposition treatment agent of the present invention include fluorinated hydrocarbons such as CHF 3 and perfluorocarbons such as CF 4 , C 2 F 6 , and C 3 F 8.
And perfluoro compounds (PFC) containing SF 6 , NF 3 and the like. Examples of such a gas containing a fluorine-containing compound include exhaust gas discharged in a process of dry cleaning the inner surface of a semiconductor manufacturing apparatus in the semiconductor industry and a process of etching various film formations.
また、本発明のＰＦＣ分解処理剤は、ＰＦＣなどに加えて、酸化性ガス、酸性ガスなども分解処理することができる。半導体製造工程から排出される排ガス中には、ＰＦＣばかりでなく、他にF2、Cl2、Br2等の酸化性ガス、HF、SiF4、COF2、HCl、HBr、SiCl4、SiBr4等の酸性ガスなどが含まれる場合がある。従来、F2、Cl2、Br2等の酸化性ガスを湿式処理する方法があるが、水だけでは完全に処理することができず、アルカリ剤や還元剤を併用するため管理や装置が複雑になる上にコストがかかる等の問題点があった。本発明のＰＦＣ分解処理剤によれば、これらの酸化性ガスや酸性ガスも、ＰＦＣ等のフッ素含有化合物と共に分解処理することができる。 Further, the PFC decomposition treatment agent of the present invention can also decompose oxidizing gas, acidic gas, etc. in addition to PFC and the like. In the exhaust gas discharged from the semiconductor manufacturing process, not only PFC but also oxidizing gases such as F 2 , Cl 2 , Br 2 , HF, SiF 4 , COF 2 , HCl, HBr, SiCl 4 , SiBr 4 And so on. Conventionally, there is a method of wet treatment of oxidizing gases such as F 2 , Cl 2 , Br 2 , but it cannot be completely treated with water alone, and management and equipment are complicated because an alkali agent and a reducing agent are used in combination. In addition, there are problems such as cost. According to the PFC decomposition treatment agent of the present invention, these oxidizing gas and acid gas can also be decomposed together with a fluorine-containing compound such as PFC.
本発明のフッ素固定剤又はＰＦＣ分解処理剤は、Al2O3とCaOとの複合酸化物であり、以下のように酸素を介して緩やかに結合していると考えられる。 The fluorine fixing agent or PFC decomposition treatment agent of the present invention is a composite oxide of Al 2 O 3 and CaO, and is considered to be loosely bonded through oxygen as follows.
本発明のフッ素固定剤をフッ素化合物と接触させると、（Al＿O）部分の触媒作用により
CF4→C＋４F
の分解反応が進み、（O_Ca）部分からの酸素（O）とカルシウム（Ca）とにより
C+2O→CO2
４F＋２Ca→２CaF2
の酸化還元反応が進むと考えられる。
When the fluorine fixing agent of the present invention is brought into contact with a fluorine compound, the catalytic action of the (Al_O) moiety
CF 4 → C + 4F
The decomposition reaction proceeds and oxygen (O) and calcium (Ca) from the (O_Ca) part
C + 2O → CO 2
4F + 2Ca → 2CaF 2
It is thought that the redox reaction proceeds.
このように、本発明のフッ素固定剤を用いてフッ素含有化合物を含む排ガスを処理すると、ＰＦＣが分解して、フッ化カルシウム（CaF2）が生成する。フッ化カルシウムは、フッ素製造の原料として知られる蛍石の主成分であり、酸で処理することによってフッ素ガスを発生させることができる。したがって、本発明のフッ素固定剤は、極めて効率的にフッ素含有化合物を含むガスからフッ素を再利用可能な形態で回収することができる。 Thus, when the exhaust gas containing a fluorine-containing compound is treated using the fluorine fixing agent of the present invention, PFC is decomposed and calcium fluoride (CaF 2 ) is generated. Calcium fluoride is a main component of fluorite known as a raw material for producing fluorine, and fluorine gas can be generated by treatment with acid. Therefore, the fluorine fixing agent of the present invention can very efficiently recover fluorine in a reusable form from a gas containing a fluorine-containing compound.
また、本発明によれば上記フッ素固定剤と、フッ素含有化合物を含む被処理ガスとを接触させることを特徴とする、フッ素含有化合物を含む被処理ガスからのフッ素回収方法が提供される。このとき、フッ素固定剤と、フッ素含有化合物を含む被処理ガスとを５５０℃〜８５０℃の温度で接触させることが好ましく、より好ましくは６００〜８００℃の範囲であり、約６５０℃〜７５０℃が最も好ましい。 In addition, according to the present invention, there is provided a method for recovering fluorine from a gas to be treated containing a fluorine-containing compound, wherein the fluorine fixing agent is brought into contact with a gas to be treated containing a fluorine-containing compound. At this time, the fluorine fixing agent and the gas to be treated containing the fluorine-containing compound are preferably brought into contact at a temperature of 550 ° C. to 850 ° C., more preferably in the range of 600 to 800 ° C., and about 650 ° C. to 750 ° C. Is most preferred.
なお、本発明のフッ素固定剤をＰＦＣ分解処理剤として使用することもできる。
以下、実施例により、本発明を更に具体的に説明する。以下の記載は、本発明の技術思想を具現化する幾つかの実施例を例示するものであり、本発明はこれらの記載によって限定されるものではない。
The fluorine fixing agent of the present invention can also be used as a PFC decomposition treatment agent.
Hereinafter, the present invention will be described more specifically with reference to examples. The following description exemplifies several embodiments that embody the technical idea of the present invention, and the present invention is not limited by these descriptions.
［フッ素固定剤１］
以下の調製例は、いずれも発生する水分を焼成容器内から速やかに排出させ、Al(OH)３とCa(OH)２との混合物と水分との接触を回避する調製方法を採用した。
[Fluorine fixative 1]
Each of the following preparation examples adopted a preparation method in which the generated moisture was quickly discharged from the baking vessel, and contact between the mixture of Al (OH) 3 and Ca (OH) 2 and moisture was avoided.
図１に示すように、均一に加熱できるように外部ヒーターを全周に具備する小型のカラム（寸法：径１５０ｍｍ×高さ８５０ｍｍ）に、Al(OH)3とCa(OH)2との混合物（Al(OH)3の平均粒子径９０μｍ、Ca(OH)2の平均粒子径５μｍ、Al(OH)3とCa(OH)2との配合割合３：７）１４Ｌを充填して、カラム内部に多量の水蒸気が滞留しないようにＮ2流量：５０L/minを上向流と下向流とで与えた。反応槽の温度を６００℃に調整して、最初にＮ2上向流を５〜６時間流してAl(OH)３とCa(OH)２との混合物層のうち上層の半分を４２０℃以上で焼成し、次にＮ2下向流を２〜３時間流してAl(OH)3とCa(OH)2との混合物層のうち下層の半分を４２０℃以上に焼成した。
As shown in Fig. 1, a mixture of Al (OH) 3 and Ca (OH) 2 in a small column (dimension: diameter 150 mm x height 850 mm) equipped with an external heater around the circumference to allow uniform heating. (Al (OH) 3 average particle diameter 90 μm, Ca (OH) 2
各焼成温度で得られたフッ素固定剤１について、水分含有量とCF4除去率を測定した結果を表１に示す。CF4除去率は、各フッ素固定剤（ＰＦＣ分解処理剤）４９ｍｌを図4に示すガス処理システム（ただし、ミニカラムは第１筒目だけとした）のミニカラム（径２２ｍｍ×高さ３００ｍｍ）に充填して、CF4流入濃度：１．０％、ガス流量：４１０ｍｌ／ｍｉｎ、処理温度：７５０℃で３時間、通ガスした後の除去率を求めた。なお、試料Ｎｏ．１−０は焼成前のAl(OH)3とCa(OH)2との混合物を意味する。
Table 1 shows the results of measuring the water content and the CF 4 removal rate of the
表１より、４２０℃でも水分含有量が１２wt%と低下しているが、Ca(OH)2の脱水温度は約４３０℃であるから、少なくとも４３０℃を超えることが好ましく、５００℃以上がより好ましいことがわかる。９１０℃の焼成温度では、水分含有量が１．６wt%でCF4除去率が９６．８％と低下していることがわかる。これは、熱劣化の影響と思われる。 From Table 1, the moisture content is reduced to 12 wt% even at 420 ° C. However, since the dehydration temperature of Ca (OH) 2 is about 430 ° C, it is preferable to exceed at least 430 ° C, more than 500 ° C. It turns out that it is preferable. It can be seen that at a firing temperature of 910 ° C., the CF 4 removal rate decreases to 96.8% when the water content is 1.6 wt%. This seems to be the effect of thermal degradation.
表１より焼成温度は５８０℃〜７８０℃が好適であることがわかる。焼成処理コストを考慮して６００℃の焼成温度で焼成したフッ素固定剤について、水分含有量とCF4除去率との関係をさらに検討した。 From Table 1, it can be seen that the firing temperature is preferably 580 ° C to 780 ° C. In consideration of the baking treatment cost, the relationship between the water content and the CF 4 removal rate was further examined for the fluorine fixing agent fired at a baking temperature of 600 ° C.
フッ素固定剤（Al(OH)3とCa(OH)2との混合物：Al(OH)3の平均粒子径９０μｍ、Ca(OH)2の平均粒子径５μｍ、Al(OH)3とCa(OH)2との混合割合３：７）をミニカラム（径２２ｍｍ×高さ３００ｍｍ）に充填し、これをセラミックス製管状炉に装着させ、窒素を４１０ｍｌ／ｍｉｎで送り込みながら６００℃に昇温した。水分調整は、焼成時間を調整することによって行った。具体的には、焼成時間５時間で水分含有量２．７ｗｔ％、焼成時間１１時間で水分含有量１．６ｗｔ％、焼成時間２４時間で水分含有量０．８ｗｔ％のフッ素固定剤が得られた。
Fluorine fixing agent (mixture of Al (OH) 3 and Ca (OH) 2 : Al (OH) 3 average particle diameter 90 μm, Ca (OH) 2
こうして得たフッ素固定剤１−８〜１−１０を各４９ｍｌ、図４に示すガス処理システム（ただし、ミニカラムは第１筒目だけとした）のミニカラムに充填し、CF4流入濃度：１．０％、ガス流量：４１０ｍｌ／ｍｉｎ、処理温度：７５０℃で５時間通ガスした後（CF4ガス出し３時間後にCF4の供給を一旦止め、窒素昇温（窒素のみで４１０ｍｌ／ｍｉｎ、７５０℃加熱）を１２時間行い、その後、CF4ガス出し（CF4流入濃度：１．０％、ガス流量：４１０ｍｌ／ｍｉｎ、処理温度：７５０℃）を２時間再開した。この通ガス方法によれば、初期性能と寿命の両方を評価することができる。）のCF4除去率を求めた。結果を表１Ａに示す。 49 ml of each of the fluorine fixing agents 1-8 to 1-10 thus obtained was packed into a minicolumn of the gas treatment system shown in FIG. 4 (however, the minicolumn was only the first cylinder), and the CF 4 inflow concentration: 1. 0%, gas flow rate: 410 ml / min, the treatment temperature after 5 hours through gas at 750 ° C. (CF 4 temporarily stopping the supply of CF 4 after degassing for three hours, 410 ml / min, 750 only with nitrogen heated (nitrogen Then, CF 4 gas out (CF 4 inflow concentration: 1.0%, gas flow rate: 410 ml / min, treatment temperature: 750 ° C.) was resumed for 2 hours. Thus, both the initial performance and lifetime can be evaluated.) The CF 4 removal rate was determined. The results are shown in Table 1A.
表１Ａから、水分含有量が０．８ｗｔ％〜２．７ｗｔ％の間で有意差がなく、水分含有量１ｗｔ％以下でも高いCF4除去率が達成されることがわかる。
得られたフッ素固定剤又はＰＦＣ分解処理剤（表１の試料Ｎｏ．１−３）のＸＲＤ分析チャートを図５に示す。上段のピークデータは得られたフッ素固定剤又はＰＦＣ分解処理剤（試料Ｎｏ．１−３）の生データからの解析ピークであり、下段のカードピークはライブラリーデータからのCaOの特性ピークである。得られたフッ素固定剤又はＰＦＣ分解処理剤（試料Ｎｏ．１−３）のピークはCaOのライブラリーデータピークと完全に一致する。参考として図６に結晶性アルミナの標準X線回折スペクトルを示すが、本実施例で得られたフッ素固定剤又はＰＦＣ分解処理剤（試料Ｎｏ．１−３）にはAl2O3の特性ピークが見られない。また、後述する比較例のＸＲＤチャートではCa(OH)2のピークが観察されることとの対比から、Ca(OH)2は全量が焼成によりCaOに変化しているといえる。これらのことから、本発明によるフッ素固定剤又はＰＦＣ分解処理剤には、焼成により発生する水分がすべて除かれ、水熱反応が進まないため、結晶性Al2O3が生じていないと考えられる。
［フッ素固定剤２］
図２に示すように、箱体の内部に収納棚を有する直接燃焼炉を用いて、各収納棚にAl(OH)3とCa(OH)2との混合物を厚さ１０ｍｍに広げて２０ｋｇとなるように充填し、空気を２０ｍ３／ｍｉｎで流し、１００℃／ｈｒの昇温速度で６時間かけて６００℃まで昇温させ、さらに６００℃で６時間焼成し、フッ素固定剤２を得た。得られたフッ素固定剤２の水分含有率は２．８ｗｔ％であった。
From Table 1A, it can be seen that there is no significant difference between the water content of 0.8 wt% and 2.7 wt%, and a high CF 4 removal rate is achieved even with a water content of 1 wt% or less.
FIG. 5 shows an XRD analysis chart of the obtained fluorine fixing agent or PFC decomposition treatment agent (sample No. 1-3 in Table 1). The upper peak data is an analysis peak from the raw data of the obtained fluorine fixing agent or PFC decomposition treatment agent (sample No. 1-3), and the lower card peak is a characteristic peak of CaO from library data. . The peak of the obtained fluorine fixing agent or PFC decomposition treatment agent (sample No. 1-3) completely coincides with the library data peak of CaO. For reference, FIG. 6 shows a standard X-ray diffraction spectrum of crystalline alumina, and the fluorine fixing agent or PFC decomposition treatment agent (sample No. 1-3) obtained in this example has a characteristic peak of Al 2 O 3 . Is not seen. In contrast to the fact that the peak of Ca (OH) 2 is observed in the XRD chart of the comparative example described later, it can be said that the entire amount of Ca (OH) 2 is changed to CaO by firing. From these things, it is considered that the fluorine fixing agent or the PFC decomposition treatment agent according to the present invention does not generate crystalline Al 2 O 3 because all the water generated by firing is removed and the hydrothermal reaction does not proceed. .
[Fluorine fixing agent 2]
As shown in FIG. 2, using a direct combustion furnace having a storage shelf inside the box, a mixture of Al (OH) 3 and Ca (OH) 2 is spread on each storage shelf to a thickness of 10 mm and 20 kg. Then, air was flowed at 20 m 3 / min, the temperature was raised to 600 ° C. over 6 hours at a temperature rising rate of 100 ° C./hr, and further calcined at 600 ° C. for 6 hours to obtain the
このフッ素固定剤２の４９ｍｌを図４に示すガス処理システム（ただし、ミニカラムは第１筒目だけとした）のミニカラム（径２２ｍｍ×高さ３００ｍｍ）に充填し、CF4流入濃度：１．０％、ガス流量：４１０ｍｌ／ｍｉｎ、処理温度：７５０℃で３時間、通ガスした後のCF4除去率を求めたところ９９．９％以上と高い除去率を示した。
［フッ素固定剤３］
図１１に示すようにロ−タリキルンは片側に投入口を設け、反対側に排出口を設けた円筒形の内筒（径約６０ｃｍ×長さ４〜５ｍ）を有し、これの下側の半周に内筒に接することなく、隙間を設けてヒ−タ−を設置している。内筒は投入口から排出口に向かって緩やかな下降傾斜があり、内筒を回転させることで、投入した剤を排出口に移動させている。移動する間に、剤はヒ−タで加熱された内筒の内側で、間接的に加熱される。内筒の中にはガスの強制送気は行わず、内部で発生したガスの上昇気流により、大気が排出口から自然吸引され、剤の流れとは逆方向に排気される構造となっている。このようなロ−タリ−キルンに、Al(OH)3とCa(OH)2との混合物（Al(OH)3の平均粒子径９０μｍ、Ca(OH)2の平均粒子径５μｍ、Al(OH)3とCa(OH)2との混合割合３：７）を２０ｋｇ／ｍｉｎの量で投入し、６２０℃±２０℃で約１時間焼成して、フッ素固定剤３を得た。ロータリーキルンを用いて間接的に加熱することによって燃料から発生するCO2の過吸着を避けた。得られたフッ素固定剤３の水分含有率は２．６ｗｔ％であった。
49 ml of this
[Fluorine fixing agent 3]
As shown in FIG. 11, the rotary kiln has a cylindrical inner cylinder (diameter: about 60 cm × length: 4 to 5 m) provided with an inlet on one side and an outlet on the opposite side. A heater is installed with a gap provided on the half circumference without contacting the inner cylinder. The inner cylinder has a gentle downward slope from the inlet to the outlet, and the charged agent is moved to the outlet by rotating the inner cylinder. During the movement, the agent is indirectly heated inside the inner cylinder heated by the heater. Gas is not forcedly fed into the inner cylinder, and the air is naturally sucked from the discharge port by the rising gas flow generated inside, and is exhausted in the direction opposite to the flow of the agent. . In such a rotary kiln, a mixture of Al (OH) 3 and Ca (OH) 2 (Al (OH) 3 average particle diameter 90 μm, Ca (OH) 2
このフッ素固定剤３の４９ｍｌを図４に示すガス処理システム（ただし、ミニカラムは第１筒目だけとした）のミニカラムに充填し、CF4流入濃度：１．０％、ガス流量：４１０ｍｌ／ｍｉｎ、処理温度：７５０℃で３時間通ガスした後のCF4除去率を求めたところ９９．９％以上と高い除去率を示した。
［フッ素固定試験］
実施例１でミニカラムにより焼成したフッ素固定剤(表１の試料Ｎｏ．１−３)を図３に示すガス処理装置に充填し、ここにCF4、C4F8、CHF3、CO、COF2、SiF4、HF、F2を含む模擬ガスを通ガスした。図３に示すガス処理装置は、カラム外周と中心部にヒーターを具備し、焼成カラム内に均一な温度に昇温しやすく構成されている。フッ素固定剤層の処理温度は７５０℃に制御し、排ガス流量は１５０Ｌ／ｍｉｎとした。入口ガス組成及び８時間処理後の出口ガス組成を表２に示す。
49 ml of this
[Fluorine fixation test]
The fluorine fixing agent (sample No. 1-3 in Table 1) calcined by the mini-column in Example 1 is filled in the gas treatment device shown in FIG. 3, where CF 4 , C 4 F 8 , CHF 3 , CO, COF 2. Simulated gas containing SiF 4 , HF and F 2 was passed. The gas processing apparatus shown in FIG. 3 includes a heater at the outer periphery and the center of the column, and is configured to easily raise the temperature to a uniform temperature in the firing column. The treatment temperature of the fluorine fixing agent layer was controlled at 750 ° C., and the exhaust gas flow rate was 150 L / min. Table 2 shows the inlet gas composition and the outlet gas composition after 8 hours of treatment.
表２より、８時間後のガス処理装置出口でＰＦＣ、ＣＯ、酸性ガスはすべて検出限界以下に良好に処理されていた。
上記ガスを処理した後に、フッ素固定剤(試料Ｎｏ．１−３)のＸＲＤ分析を行った。図７に示すＸＲＤチャートから、CaOの特性ピークのほかにCaF2のX線回折ピークが出現しており、フッ素固定剤１にFが固定されたことが確認された。
From Table 2, PFC, CO, and acidic gas were all processed well below the detection limit at the gas processing apparatus outlet after 8 hours.
After treating the gas, an XRD analysis of the fluorine fixing agent (Sample No. 1-3) was performed. From the XRD chart shown in FIG. 7, an X-ray diffraction peak of CaF 2 appeared in addition to the characteristic peak of CaO, and it was confirmed that F was fixed to the
対照として、図３に示すガス処理装置（大型カラム。径３５０ｍｍ×高さ８５０ｍｍ）にAl(OH)3とCa(OH)2との混合物を９４Ｌ充填して、Ｎ2流量：６０L/minを下向流に流し、３００℃で８時間、５００℃で９時間、次いで７５０℃で８時間かけて焼成した。図３の大型カラム内の混合物を縦方向に9等分し、上からＮｏ．１〜Ｎｏ．９とし、焼成後、図３に示す各層ごとに一定量を採取して、熱分析により水分含有量を測定し、ＸＲＤ分析により結晶性化合物を同定した。図８に、試料No.5についてのＸＲＤ分析チャートの例を示す。CaOとCa(OH)2のピークが観察された。 As a control, 94 L of a mixture of Al (OH) 3 and Ca (OH) 2 was filled in the gas processing apparatus (large column, diameter 350 mm × height 850 mm) shown in FIG. 3, and N 2 flow rate: 60 L / min. It was made to flow downward and calcined at 300 ° C. for 8 hours, at 500 ° C. for 9 hours, and then at 750 ° C. for 8 hours. Divide the mixture in the large column of FIG. 1-No. After firing, a certain amount was collected for each layer shown in FIG. 3, the water content was measured by thermal analysis, and the crystalline compound was identified by XRD analysis. In FIG. 8, the example of the XRD analysis chart about sample No. 5 is shown. CaO and Ca (OH) 2 peaks were observed.
また、得られた焼成体４９mlを図４に示すガス処理システム（ただし、ミニカラムは第１筒目だけとした）のミニカラム（径２２ｍｍ×高さ３００ｍｍ）に充填して、CF4流入濃度：１．０％、ガス流量：４１０ml/min、処理温度：７５０℃で３時間、通ガスした後の除去率を求めた。結果を表３に示す。なお、表中、試料Ｎｏ．とは図３に示す採取した層の位置を示す。また、試料Ｎｏ．０は、未焼成のAl(OH)3とCa(OH)2との混合物を意味する。 The gas processing system according to fired body 49ml obtained in FIG. 4 (where minicolumns were only first cylinder th) was charged into a mini-column (diameter 22 mm × height 300 mm) of, CF 4 concentration of inflow: 1 0.0%, gas flow rate: 410 ml / min, treatment temperature: 750 ° C., and the removal rate after passing gas for 3 hours was determined. The results are shown in Table 3. In the table, sample No. Indicates the position of the collected layer shown in FIG. Sample No. 0 means a mixture of unsintered Al (OH) 3 and Ca (OH) 2 .
表３より、採取位置によって水分含有量及びＸＲＤ分析結果に差異が見られ、均一な焼成が行われていないことがわかる。特に中段層〜下段層から採取した焼成体のCF4除去率が非常に低くなっている。これは、７５０℃以上の高温条件下で焼成を行う際に発生する水分が混合物の周囲に滞留して高温多湿条件を創製し、水熱合成反応が生じ、結晶化を促進させ、活性を低下させたものと考えられる。 From Table 3, it can be seen that there is a difference in moisture content and XRD analysis results depending on the sampling position, and uniform baking is not performed. In particular, the CF 4 removal rate of the fired bodies collected from the middle layer to the lower layer is very low. This is because moisture generated when firing under a high temperature condition of 750 ° C. or more stays around the mixture to create a high temperature and high humidity condition, a hydrothermal synthesis reaction occurs, promotes crystallization, and decreases activity It is thought that it was made.
また、CF4除去後の試料についてＸＲＤ分析を行った。ＸＲＤ分析チャートの例を図９に示す。図８のＸＲＤ分析チャートと比較すると、Ca(OH)2が消失し、代わりにCaF2のピークが観察される。 Also, were XRD analyzed samples after CF 4 is removed. An example of the XRD analysis chart is shown in FIG. Compared with the XRD analysis chart of FIG. 8, Ca (OH) 2 disappears and a CaF 2 peak is observed instead.
［CF4処理試験］
図４に示す構成のガス処理システムを用いて、７５０℃で１．５時間焼成した本発明のＰＦＣ分解処理剤（フッ素固定剤）の性能を調べた。外周にセラミックス製管状炉を取り付けたＳＵＳ製ミニカラム（径２２ｍｍ×高さ３００ｍｍ）２本を直列に接続させて、各ミニカラムに本発明のＰＦＣ分解処理剤４９mlを充てんし、ＰＦＣ分解処理剤層が７５０℃で安定したところでCF4流入濃度：１．０％、ガス流量：４１０ml/minでCF4の通ガスを開始した。性能の比較は、ミニカラムの２筒目の出口でCF4除去率が９５％を下回るまでの処理時間を計測し、処理時間が長いほど性能が良好であると判断した。表４には、平均粒子径１２０μｍのAl(OH)3を用いた場合のAl（OH）3対Ca（OH）2のモル比を変数として性能を比較した結果を示す。
[CF 4 treatment test]
The performance of the PFC decomposition treatment agent (fluorine fixing agent) of the present invention baked at 750 ° C. for 1.5 hours was examined using the gas treatment system having the configuration shown in FIG. Two SUS mini-columns (diameter 22 mm x height 300 mm) with a ceramic tube furnace attached to the outer periphery were connected in series, and each mini-column was filled with 49 ml of the PFC decomposition treatment agent of the present invention, CF 4 concentration of inflow at a stable at 750 ° C.: 1.0%, flow rate: started 410 ml / min in a flow-through gas of CF 4. In the performance comparison, the processing time until the CF 4 removal rate fell below 95% was measured at the outlet of the second cylinder of the mini column, and it was judged that the longer the processing time, the better the performance. Table 4 shows the results of performance comparison using Al (OH) 3 to Ca (OH) 2 molar ratio as a variable when Al (OH) 3 having an average particle size of 120 μm is used.
表４より、同じ平均粒子径であれば、Al(OH)3：Ca(OH)2のモル比が、３：７〜５：５の範囲で良好な処理性能を示し、３：７の時に処理性能が最大となることがわかる。
次に、図４に示すガス処理システムを用いて、同じ処理条件にて、Al(OH)3：Ca(OH)2のモル比を３：７として７５０℃で１．５時間焼成した場合のAl(OH)3の平均粒子径とCF4処理性能との関係を調べた。その際に、Ca(OH)2は平均粒子径（メディアン径）５μｍのもの用いた。結果を表５に示す。
Table 4 shows that when the average particle size is the same, Al (OH) 3 : Ca (OH) 2 molar ratio is in the range of 3: 7 to 5: 5, showing good processing performance. It can be seen that the processing performance is maximized.
Next, when the gas treatment system shown in FIG. 4 is used and the same treatment conditions are used, the molar ratio of Al (OH) 3 : Ca (OH) 2 is set to 3: 7 and baked at 750 ° C. for 1.5 hours. The relationship between the average particle size of Al (OH) 3 and CF 4 treatment performance was investigated. At that time, Ca (OH) 2 having an average particle diameter (median diameter) of 5 μm was used. The results are shown in Table 5.
表５より、Al(OH)３の平均粒子径が大きいほど、処理性能が向上する傾向が認められた。
上述の各試験例の結果から、性能上はAl(OH)3：Ca(OH)2のモル比が３：７でAl(OH)3の平均粒子径が１２０μｍである場合に最も高いCF4処理性能が得られることがわかる。しかし、工業ベースでこの組成を用いて量産すると、粉末品の回収率が悪く、コスト高になるため、同じモル比で平均粒子径を９０μmにして製品化を図った。この組成で同じ条件で性能評価したところ、CF4除去率が９５％時の処理時間は３４．８時間となり、最適組成と比較して大きな差がないことを確認した。さらに、Al(OH)3を篩いにかけずに使用した場合には、平均粒子径が５５μｍであったが、CF4除去率が９５％時の処理時間は３１．２時間であることが確認できた。この処理時間は、Al(OH)3を篩いにかけて得られる平均粒子径６０μｍの処理時間３１．５時間と差がない。CF4除去率が９５％時の処理時間は３０時間以上であれば実用に耐えることから、製造コスト（篩い分け）と性能とのバランスを考慮すれば、Al(OH)3は平均粒子径５５μｍ以上でよいことになる。
From Table 5, the tendency for process performance to improve was recognized, so that the average particle diameter of Al (OH) 3 was large.
From the results of the above test examples, the highest CF 4 in terms of performance when the molar ratio of Al (OH) 3 : Ca (OH) 2 is 3: 7 and the average particle diameter of Al (OH) 3 is 120 μm. It can be seen that processing performance is obtained. However, if mass production is performed using this composition on an industrial basis, the recovery rate of powder products is poor and the cost is high. Therefore, commercialization was attempted with an average particle size of 90 μm at the same molar ratio. When performance was evaluated under the same conditions with this composition, the treatment time when the CF 4 removal rate was 95% was 34.8 hours, and it was confirmed that there was no significant difference compared to the optimum composition. Further, when Al (OH) 3 was used without sieving, the average particle size was 55 μm, but it was confirmed that the treatment time when the CF 4 removal rate was 95% was 31.2 hours. It was. This treatment time is not different from the treatment time of 31.5 hours with an average particle diameter of 60 μm obtained by sieving Al (OH) 3 . If the treatment time when the CF 4 removal rate is 95% is 30 hours or more, it can withstand practical use. Therefore, considering the balance between production cost (sieving) and performance, Al (OH) 3 has an average particle diameter of 55 μm. That's all there is to it.
また、CF4除去試験後のフッ素固定剤についてＸＲＤ分析を行った。ＸＲＤチャートを図１０に示す。CaOのピークの他に、CaF2のピークが観察され、フッ素固定剤にFが固定されたことがわかる。 Furthermore, an XRD analysis was performed on the fluorine fixative after CF 4 removal test. An XRD chart is shown in FIG. In addition to the CaO peak, a CaF 2 peak was observed, indicating that F was fixed to the fluorine fixing agent.
本発明のフッ素固定剤は、非晶質Al2O3とCaOとの複合酸化物であると考えられる。比較のため、市販のα型結晶質Al2O3（粒径２０μｍの粉末）とCaO（粉末）とのモル比３：７の単純混合物を圧縮成型して１〜４ｍｍの粉砕品を調製し、図４に示すガス処理システム（ただし、ミニカラムは第１筒目だけとした）でCF4処理を行った。ガス処理システムのミニカラムに単純混合物４９ｍｌを充填し、６５０℃で安定したところでCF4流入濃度：１．０％、ガス流量：４１０ｍｌ／ｍｉｎでCF4の通ガスを開始し、処理時間によるCF4除去率の変化をみた。本発明のフッ素固定剤(試料Ｎｏ．１−３)を用いて６５０℃の処理温度で行った場合のCF4除去率と合わせて表６に示す。 The fluorine fixing agent of the present invention is considered to be a composite oxide of amorphous Al 2 O 3 and CaO. For comparison, a simple mixture of commercially available α-type crystalline Al 2 O 3 (powder having a particle size of 20 μm) and CaO (powder) in a molar ratio of 3: 7 is compression molded to prepare a 1 to 4 mm pulverized product. , CF 4 treatment was performed with the gas treatment system shown in FIG. 4 (however, the mini column was only the first cylinder). Filling the simple mixture 49ml to mini-column of a gas processing system, stable at by CF 4 concentration of inflow at 650 ° C.: 1.0%, flow rate: starts passing gas CF 4 at 410 ml / min, depending on the processing time CF 4 Change in removal rate was observed. Table 6 shows the CF 4 removal rate when the fluorine fixing agent (Sample No. 1-3) of the present invention is used and treated at a processing temperature of 650 ° C.
表６に示す結果から明らかなように、α−Al2O3とCaOの単純混合物では、本発明のフッ素固定剤とくらべて、活性が低いだけでなく、処理開始後短時間で実用に耐えない程度に性能が劣化してしまう。 As is apparent from the results shown in Table 6, the simple mixture of α-Al 2 O 3 and CaO is not only less active than the fluorine fixing agent of the present invention, but also withstands practical use in a short time after the start of treatment. Performance will deteriorate to the extent that it is not.
実施例１で調製したフッ素固定剤（試料Ｎｏ．１−３）１００Ｌを実機反応槽（直径３５０ｍｍ×高さ８５０ｍｍ、外部ヒーター及び内部ヒーター装備）に充填し、窒素ガス５０Ｌ／ｍｉｎを流し込みながら７５０℃まで８時間かけて昇温し、フィールド評価を行った。実機反応槽で処理する実排ガスは、ＰＦＣ（CF4、C2F4、C2F6、C3F6、C3F8、C4F8、CHF3、CH3F2、NF3）と酸性ガス（COF2、SiF4、F2、HF）とCO、CH4、N2O、H2を含んでいた。フィールド評価は、実排ガス流量１５０Ｌ／ｍｉｎ、パージ用空気１０Ｌ／ｍｉｎを導入し、反応槽内を７５０℃に制御して、ＰＦＣ除去率が８６〜８８％になった時点で処理を終了し、処理終了時点でのフッ素固定剤のＦ吸着量を測定して行った。対照として、実機反応槽にAl(OH)3及びCa(OH)2を焼成せずにそのまま充填し、窒素ガス５０Ｌ／ｍｉｎを流し込みながら３００℃で８時間、ついで５００℃で８時間、さらに７５０℃で８時間かけて昇温し、同様にフィールド評価を行った。結果を表７に示す。 100 L of the fluorine fixing agent (sample No. 1-3) prepared in Example 1 was filled into an actual reactor (diameter 350 mm × height 850 mm, equipped with an external heater and an internal heater), and nitrogen gas 50 L / min was flowed to 750. The temperature was raised to 8 ° C. over 8 hours, and field evaluation was performed. The actual exhaust gas treated in the actual reactor is PFC (CF 4 , C 2 F 4 , C 2 F 6 , C 3 F 6 , C 3 F 8 , C 4 F 8 , CHF 3 , CH 3 F 2 , NF 3 ) And acid gases (COF 2 , SiF 4 , F 2 , HF) and CO, CH 4 , N 2 O, H 2 . In the field evaluation, an actual exhaust gas flow rate of 150 L / min, purge air of 10 L / min is introduced, the inside of the reaction vessel is controlled to 750 ° C., and the process is terminated when the PFC removal rate reaches 86 to 88%. The measurement was performed by measuring the F adsorption amount of the fluorine fixing agent at the end of the treatment. As a control, Al (OH) 3 and Ca (OH) 2 were filled in an actual reactor without firing, and nitrogen gas was supplied at 50 L / min for 8 hours at 300 ° C., then at 500 ° C. for 8 hours, and further at 750 The temperature was raised at 8 ° C. over 8 hours, and field evaluation was performed in the same manner. The results are shown in Table 7.
対照混合物の処理後のカラムからは、水がでてきた。
表７より、本発明のフッ素固定剤は、未焼成の対照混合物と異なり実排ガス処理中に水分を発生せず、Ｆ吸着量（ＣＦ４処理量）で約２倍強の処理量を行うことができたことがわかる。
Water emerged from the column after treatment of the control mixture.
From Table 7, the fluorine fixing agent of the present invention does not generate moisture during the actual exhaust gas treatment unlike the unfired control mixture, and the amount of F adsorption (CF 4 treatment amount) is about twice as high. You can see that
ＰＦＣの分解作用に対するＮａの影響を調べた。
Ｎａ含有量とCF4処理性能の関係を求めるため、ＰＦＣ分解処理剤を次の条件で焼成し、Ｎａ含有量の異なる処理剤を調製した。表８に、Ｎａ含有量の異なるＰＦＣ分解処理剤による処理能力の比較を示す。ＰＦＣ分解処理剤は、Al(OH)3の平均粒子径90μm、Ca(OH)2の平均粒子径5μmを、Al(OH)3とCa(OH)2との配合比率３対７として混合し、ミニカラム（径22 mm×高さ300mm）に充てんし、これをセラミックス製管状炉に装着し、N2 410 mL／minを送気しながら、600℃で5 時間焼成した。これらＰＦＣ分解処理剤の各49 mLを図４に示すガス処理システム（ただし、ミニカラムは１筒目だけとした）のミニカラムに充てんし、CF4 流入濃度：1.0%，ガス流量：410 mL／min、処理温度：７５０℃で３〜４時間通ガスした後に、窒素のみで410mL／min、７５０℃で加熱し、再度CF4流入濃度：1.0%、ガス流量：410 mL／min、処理温度：７５０℃で、CF4除去率が95%に低下するまでの処理時間を求めた。Na含有量が少ないほど処理時間が長くなる傾向があり、Na含有量とCF4処理性能の間に相関がみられた。
The influence of Na on the decomposition action of PFC was investigated.
In order to obtain the relationship between the Na content and the CF 4 treatment performance, the PFC decomposition treatment agent was calcined under the following conditions to prepare treatment agents having different Na contents. Table 8 shows a comparison of treatment capacities with PFC decomposition treatment agents having different Na contents. PFC decomposition treatment agent mixes Al (OH) 3 average particle size 90μm and Ca (OH) 2 average particle size 5μm in the mixing ratio 3: 7 of Al (OH) 3 and Ca (OH) 2. This was packed in a mini-column (diameter 22 mm x height 300 mm), mounted in a ceramic tube furnace, and fired at 600 ° C. for 5 hours while supplying N 2 410 mL / min. 49 mL of each of these PFC decomposition treatment agents is packed into a mini-column of the gas processing system shown in FIG. 4 (however, the mini-column is only the first cylinder), CF 4 inflow concentration: 1.0%, gas flow rate: 410 mL / min Processing temperature: After passing gas at 750 ° C. for 3 to 4 hours, heating with nitrogen alone at 410 mL / min and 750 ° C., CF 4 inflow concentration: 1.0%, gas flow rate: 410 mL / min, processing temperature: 750 The processing time until the CF 4 removal rate decreased to 95% at ℃ was determined. There was a tendency for the treatment time to become longer as the Na content decreased, and a correlation was observed between the Na content and the CF 4 treatment performance.
処理耐用時間は長い方が好ましいため、焼成品のＮａ含有量は、好ましくは０．０３ｗｔ％以下、より好ましくは０．０１ｗｔ％以下である。
このような処理剤を得るために、原料として、０．０３ｗｔ％以下、好ましくは０．０１ｗｔ％以下Naを含むAl(OH)3と、０．０３ｗｔ％以下、好ましくは０．０１ｗｔ％以下のNaを含むCa(OH)2を用いるとよい。
Since it is preferable that the treatment lifetime is long, the Na content of the fired product is preferably 0.03 wt% or less, more preferably 0.01 wt% or less.
In order to obtain such a treatment agent, as raw materials, 0.03 wt% or less, preferably 0.01 wt% or less Al (OH) 3 containing Na, 0.03 wt% or less, preferably 0.01 wt% or less Ca (OH) 2 containing Na may be used.
Claims (21)
項１又は２に記載の方法。 The method according to claim 1 or 2, wherein the mixture is calcined without being in direct contact with CO 2 generated by combustion of fuel.
に記載の方法。 The calcination is performed without direct contact with CO 2 generated by combustion of fuel.
The method described in 1.
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| JP5016616B2 (en) * | 2009-01-08 | 2012-09-05 | 株式会社荏原製作所 | Method for treating exhaust gas containing fluorine compound and reaction tank for treatment |
| JP5016618B2 (en) * | 2009-01-15 | 2012-09-05 | 株式会社荏原製作所 | Method for treating exhaust gas containing SF6 |
| JP5476043B2 (en) * | 2009-06-03 | 2014-04-23 | 株式会社荏原製作所 | Method and apparatus for treating exhaust gas containing fluorine compound |
| JP5423594B2 (en) * | 2010-06-23 | 2014-02-19 | セントラル硝子株式会社 | Method for removing fluorine-containing compound gas |
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