JP2004174416A - Recovery method for hydrofluoric acid - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は、フッ酸の回収方法に関する。さらに詳しくは、本発明は、フッ酸含有排水から、効率的にフッ酸を回収するとともに、蒸留水をも回収して再利用することができるフッ酸の回収方法に関する。
【０００２】
【従来の技術】
フッ酸含有排水は、金属表面処理業、ガラス工業、リン肥料製造業、半導体製造業などの種々の産業分野で排出される。排水中に含まれるフッ素の処理方法としては、水酸化カルシウム、塩化カルシウム、炭酸カルシウムなどのカルシウム化合物との反応により、水不溶性のフッ化カルシウムとして析出させ、除去する方法が広く行われている。また、処理水中のフッ素の濃度をさらに低下させるために、カルシウム化合物とアルミニウム化合物を用いて二段凝集処理する方法や、フッ素を吸着するキレート樹脂などを用いて、排水中のフッ素を吸着除去する方法などが提案されている。例えば、ジルコニウム担持樹脂を用いて効率よくフッ化物イオンの除去を行い、しかも処理液を過不足なく中和して放流することができるフッ化物イオン除去装置として、ジルコニウム担持カチオン交換樹脂を有する吸着塔に被処理液を供給し、フッ化物イオンを選択的に吸着除去し、ＯＨ形弱塩基性アニオン交換樹脂層を有するｐＨ調整塔に、酸性の吸着塔処理液を供給して中和的にイオン交換を行う装置が提案されている（特許文献１）。
フッ素含有排水から、フッ素を除去するのみならず、水を回収して再利用する試みもなされている。例えば、低濃度フッ素含有水と高濃度フッ素含有水が排出される系において、各々のフッ素含有水を効率的に処理して、高純度処理水を得る方法として、低濃度フッ素含有水をフッ素吸着樹脂と接触させる工程、フッ素吸着樹脂を再生処理する工程、高濃度フッ素含有水にフッ素吸着樹脂の再生廃液を添加したのち、カルシウム化合物を加えて凝集処理し、次いで固液分離する工程を備えるフッ素含有水の処理方法が提案されている（特許文献２）。また、フッ素含有排水を蒸発濃縮して大部分の水を蒸留水として回収する方法として、フッ素含有排水に苛性ソーダ水溶液又は苛性カリ水溶液を添加し、水の蒸発に伴うフッ化水素酸の気化を抑える方法が提案されている（特許文献３）。
さらに、フッ素含有排水から、フッ素を回収する試みもなされている。例えば、半導体製造工程から排出されるリンス排水をアニオン交換樹脂で処理し、樹脂の再生廃液を短時間で低コストかつ効率的に処理して高純度処理水を得るとともに、フッ素をフッ化カルシウムとして効率的に回収して有効再利用を可能とする方法として、得られる再生廃液をフッ素濃厚再生廃液とフッ素希薄再生廃液とに分別し、フッ素濃厚再生廃液は炭酸カルシウム充填塔に通液し、フッ素希薄再生廃液は凝集槽で凝集処理するリンス排水の処理方法が提案されている（特許文献４）。また、半導体製造工程などから排出されるフッ化物イオンを含有する排水を薬剤を使用することなく処理して、フッ化物イオンが除去された排水を得るとともに、フッ化物イオンをフッ化水素酸として工場内回収できる排水処理方法として、フッ化物イオンを排水を通液型コンデンサに供給し、一対の電極に直流電圧を印加して排水からフッ化物イオンを除去する脱塩工程からフッ化物イオン濃度が低減された排水を得、その後一対の電極を短絡あるいは直流電源を逆接続して、除去されたフッ化物イオン成分を通液中の排水とともに回収する濃縮工程からフッ化水素酸を得る排水処理方法が提案されている（特許文献５）。
【特許文献１】
特開平８−８９９４９号公報（第２頁、第５頁）
【特許文献２】
特開平５−９２１８７号公報（第２頁、第４頁）
【特許文献３】
特開平９−２７１７８５号公報（第２頁、第６頁）
【特許文献４】
特開平６−２７７６６３号公報（第２頁、第５頁）
【特許文献５】
特開２００１−１１３２８４号公報（第２頁、第６−７頁）
【０００３】
【発明が解決しようとする課題】
本発明は、フッ酸含有排水から、効率的にフッ酸を回収するとともに、蒸留水をも回収して再利用することができるフッ酸の回収方法を提供することを目的としてなされたものである。
【０００４】
【課題を解決するための手段】
本発明者らは、上記の課題を解決すべく鋭意研究を重ねた結果、フッ酸含有排水中のフッ化水素をフッ化カリウムとしたのち、蒸発濃縮してフッ化カリウム濃度１５重量％以上、溶解度濃度以下の濃縮液を生成し、得られた濃縮液からフッ酸を回収することにより、効率的なフッ酸の回収が可能となり、さらに、フッ酸含有排水の濃度が希薄な場合は、排水をフッ素キレート樹脂に接触させたのち、キレート樹脂に水酸化カリウム水溶液を脱着液として供給してフッ化カリウム含有液を得、この液を同様に濃縮して処理することにより、あるいは、得られるフッ化カリウム含有液と濃厚フッ酸含有排水とを混合したのち、同様に濃縮して処理することにより、効率的なフッ酸の回収が可能となることを見いだし、この知見に基づいて本発明を完成するに至った。
すなわち、本発明は、
（１）フッ酸含有排水に塩基性カリウム化合物を添加してフッ化水素をフッ化カリウムとしたのち、蒸発濃縮してフッ化カリウム濃度１５重量％以上、溶解度濃度以下の濃縮液を生成し、得られた濃縮液からフッ酸を回収することを特徴とするフッ酸含有排水からのフッ酸の回収方法、
（２）希薄フッ酸含有排水をフッ素キレート樹脂に接触させ、次いでフッ素を吸着したキレート樹脂に水酸化カリウム水溶液を脱着液として供給してフッ化カリウム含有液を得たのち、蒸発濃縮してフッ化カリウム濃度１５重量％以上、溶解度濃度以下の濃縮液を生成し、得られた濃縮液からフッ酸を回収することを特徴とするフッ酸含有排水からのフッ酸の回収方法、
（３）希薄フッ酸含有排水をフッ素キレート樹脂に接触させ、次いでフッ素を吸着したキレート樹脂に水酸化カリウム水溶液を脱着液として供給してフッ化カリウム含有液を得、得られたフッ化カリウム含有液と濃厚フッ酸含有排水とを混合したのち、蒸発濃縮してフッ化カリウム濃度１５重量％以上、溶解度濃度以下の濃縮液を生成し、得られた濃縮液からフッ酸を回収することを特徴とするフッ酸含有排水からのフッ酸の回収方法、及び、
（４）濃縮液に硫酸を添加してフッ化カリウムからフッ酸を生成し、生成したフッ酸を回収する第１項、第２項又は第３項記載のフッ酸含有排水からのフッ酸の回収方法、
を提供するものである。
【０００５】
【発明の実施の形態】
本発明方法の第一の態様においては、フッ酸含有排水に塩基性カリウム化合物を添加してフッ化水素をフッ化カリウムとしたのち、蒸発濃縮してフッ化カリウム濃度１５重量％以上、溶解度濃度以下の濃縮液を生成し、得られた濃縮液からフッ酸を回収する。
本発明方法の第二の態様においては、希薄フッ酸含有排水をフッ素キレート樹脂に接触させ、次いでフッ素を吸着したキレート樹脂に水酸化カリウム水溶液を脱着液として供給してフッ化カリウム含有液を得たのち、蒸発濃縮してフッ化カリウム濃度１５重量％以上、溶解度濃度以下の濃縮液を生成し、得られた濃縮液からフッ酸を回収する。
本発明方法の第三の態様においては、希薄フッ酸含有排水をフッ素キレート樹脂に接触させ、次いでフッ素を吸着したキレート樹脂に水酸化カリウム水溶液を脱着液として供給してフッ化カリウム含有液を得、得られたフッ化カリウム含有液と濃厚フッ酸含有排水とを混合したのち、蒸発濃縮してフッ化カリウム濃度１５重量％以上、溶解度濃度以下の濃縮液を生成し、得られた濃縮液からフッ酸を回収する。
本発明方法においては、フッ化カリウム濃度１５重量％以上、溶解度濃度以下の濃縮液に硫酸を添加して、フッ化カリウムからフッ酸を生成し、生成したフッ酸を回収することができる。
【０００６】
本発明方法を適用するフッ酸含有排水に特に制限はなく、例えば、半導体製造工場において発生するエッチング排液やリンス排水、金属表面処理工場、ガラス工場などの排水などを挙げることができる。本発明方法は、濃厚なフッ酸含有排水と、希薄なフッ酸含有排水がともに排出される工場に特に好適に適用することができる。濃厚フッ酸含有排水とは、フッ化水素濃度５０ｍｇ／Ｌ以上の排水であり、希薄フッ酸含有排水とは、フッ化水素濃度５０ｍｇ／Ｌ未満の排水である。
本発明方法においては、フッ酸含有排水に塩基性カリウム化合物を添加して、フッ化水素をフッ化カリウムとしたのち蒸発濃縮する。使用する塩基性カリウム化合物としては、例えば、水酸化カリウム、炭酸カリウム、炭酸水素カリウムなどを挙げることができる。水酸化カリウムを用いると、フッ化水素は、次式にしたがってフッ化カリウムとなる。
ＨＦ ＋ ＫＯＨ → ＫＦ ＋ Ｈ２Ｏ
フッ酸含有排水はｐＨが低いので、直接排水を蒸発濃縮すると、装置の腐食、フッ化水素の蒸気側への移行などの問題が生ずる。排水中のフッ化水素をフッ化カリウムとしたのち、蒸発濃縮することにより、フッ化水素による悪影響を防止することができる。
フッ酸の中和剤としては、水酸化カリウムなどのカリウム化合物のほかに、水酸化ナトリウムなどのナトリウム化合物も考えられる。水酸化ナトリウムで中和すると、フッ化水素はフッ化ナトリウムとなり、水酸化カリウムで中和すると、フッ化水素はフッ化カリウムとなる。中和後の排水から水を蒸発させると、排水中のフッ化ナトリウム又はフッ化カリウムが濃縮され、溶解度を超えると塩が析出する。塩が析出すると、蒸発装置の効率の低下や、スケール化などの障害が発生するので、蒸発濃縮は塩の溶解度濃度以下にとどめる必要がある。水酸化ナトリウムの水に対する溶解度は６０℃において４．５重量％であるのに対して、フッ化カリウムの水に対する溶解度は６０℃において５８．７重量％である。したがって、フッ化水素をフッ化カリウムにして蒸発すると、フッ化ナトリウムにした場合に比べて大幅に濃縮度を上げることができ、高濃度のフッ化カリウムを含有する液として、効率的にフッ酸を回収することができる。
【０００７】
本発明方法においては、蒸発濃縮により、フッ化カリウム濃度１５重量％以上、溶解度濃度以下の濃縮液を生成し、より好ましくはフッ化カリウム濃度２０〜５０重量％の濃縮液を生成する。フッ化カリウム濃度１５重量％未満であると、フッ酸の回収効率が低下するおそれがある。本発明方法においては、蒸発温度におけるフッ化カリウムの溶解度まで濃縮することができる。しかし、濃縮液のフッ化カリウム濃度を５０重量％以下とすると、濃縮液の温度が２５℃まで低下しても塩が析出しないので操作が容易である。
本発明方法に用いる蒸発装置に特に制限はなく、例えば、液中燃焼方式、自然循環式浸管型、自然循環式水平管型、垂直短管型、垂直長管上昇膜型、水平管下降膜型、垂直長管下降膜型、強制循環式水平管型、強制循環式垂直管型、コイル型、攪拌膜型、遠心式薄膜型、プレート型、フラッシュ蒸発方式などの蒸発装置を挙げることができる。本発明方法において、蒸発装置の配列と操作方式に特に制限はなく、例えば、単一缶、蒸気圧縮法、多重効用法、多段フラッシュ蒸発法などを挙げることができる。
本発明方法において、フッ化カリウム水溶液の蒸発装置から発生する蒸気は、冷却して凝縮水として排出することができる。排水中のフッ酸はフッ化カリウムとなっているので、フッ化水素のように蒸気側にはほとんど移行せず、凝縮水に含まれるフッ素はごくわずかである。必要に応じて、さらに凝縮水中のフッ素を、フッ素吸着樹脂、炭酸カルシウム充填塔、逆浸透膜装置、連続式脱イオン装置などを用いて完全に除去することができる。凝縮水は、再利用することができ、あるいは、放流することもできる。
本発明方法においては、蒸発濃縮により得られたフッ化カリウムを１５重量％以上含有する濃縮液からフッ酸を回収する。フッ酸を回収する方法に特に制限はなく、例えば、濃縮液に硫酸を添加し、次式にしたがってフッ化カリウムをフッ化水素に変換することができる。
２ＫＦ ＋ Ｈ２ＳＯ４ → ２ＨＦ ＋ Ｋ２ＳＯ４
硫酸の添加量は、濃縮液中のフッ化カリウムに対して反応当量以上であることが好ましく、１．２〜２当量倍であることがより好ましい。硫酸が添加され、フッ化水素と硫酸カリウムを含む濃縮液は、例えば、６０〜１００℃に加温して、液中のフッ化水素を気化し、次いで、フッ化水素を含むガスを吸収塔に導き、水と気液接触させてフッ化水素を水に吸収させることができる。フッ化水素の吸収液は、回収して再利用することができる。
【０００８】
本発明方法の第二の態様においては、希薄フッ酸含有排水をフッ素キレート樹脂に接触させ、次いでフッ素を吸着したキレート樹脂に水酸化カリウム水溶液を脱着液として供給して、フッ化カリウム含有液を得る。希薄フッ酸含有排水をキレート樹脂と接触させてフッ素を吸着させ、水酸化カリウム水溶液を用いて脱着させることにより、濃厚なフッ化カリウム水溶液を得ることができる。希薄フッ酸含有排水に水酸化カリウムを加えて得られる希薄フッ化カリウム水溶液を蒸発濃縮する場合と比べて、多量の水を蒸発するための熱エネルギーを節減することができる。使用するフッ素キレート樹脂に特に制限はなく、例えば、セリウム、ハフニウム、チタン、ジルコニウム、鉄、アルミニウムなどのフッ素イオンと錯化合物を形成する金属イオンを吸着した樹脂、ホスホメチルアミノ基を有するキレート樹脂などを挙げることができる。
希薄フッ酸含有排水をフッ素キレート樹脂と接触させる方法に特に制限はなく、例えば、フッ素キレート樹脂を充填した充填塔に希薄フッ酸含有排水を通水することができる。フッ素イオンをフッ素キレート樹脂に吸着させ、樹脂の吸着能が飽和したとき、脱着液を充填塔に通液して、樹脂に吸着したフッ素を脱離させることが好ましい。脱離液のフッ素は、原排水に比べて濃縮されている。脱着液として水酸化カリウム水溶液を使用することにより、脱離液中のフッ素はフッ化カリウムとなる。脱離液を蒸発濃縮することにより、フッ化カリウム濃度１５重量％以上、溶解度濃度以下の濃縮液とし、この濃縮液からフッ酸を回収する。
【０００９】
本発明の第三の態様においては、希薄フッ酸含有排水をフッ素キレート樹脂に接触させ、次いでフッ素を吸着したキレート樹脂に水酸化カリウム水溶液を脱着液として供給してフッ化カリウム含有液を得、得られたフッ化カリウム含有液と濃厚フッ酸含有排水とを混合したのち、蒸発濃縮する。半導体製造工場などのように、エッチング排液などの濃厚フッ酸含有排水と、リンス排水などの希薄フッ酸含有排水が同一個所で発生する場合には、本態様の方法を好適に用いることができる。希薄フッ酸含有排水をキレート樹脂と接触させてフッ素を吸着させ、水酸化カリウム水溶液を用いて脱着させることにより、濃厚なフッ化カリウム水溶液を得ることができる。使用するフッ素キレート樹脂に特に制限はなく、例えば、セリウム、ハフニウム、チタン、ジルコニウム、鉄、アルミニウムなどのフッ素イオンと錯化合物を形成する金属イオンを吸着した樹脂、ホスホメチルアミノ基を有するキレート樹脂などを挙げることができる。吸着されたフッ素の脱着には、通常はフッ素に対して当量以上の水酸化カリウムが用いられるので、脱着により得られるフッ化カリウム含有液中には過剰の水酸化カリウムが含まれる。このフッ化カリウム含有液を濃厚フッ酸含有排水と混合することにより、フッ化カリウム含有液中に含まれる水酸化カリウムを濃厚フッ酸含有排水中のフッ酸の中和に利用することができる。
【００１０】
図１は、本発明方法の第一の態様の工程系統図である。中和槽１において、フッ酸含有排水に水酸化カリウム水溶液が添加され、フッ化水素がフッ化カリウムに変換される。フッ化カリウム水溶液は、蒸発缶２において蒸発濃縮される。発生する蒸気は凝縮器３で冷却され、得られる凝縮水はフッ素吸着塔４に通水されて含有する微量のフッ素が除去され、回収水として利用される。蒸発缶の濃縮液は、酸発生槽５において硫酸が添加され、液中のフッ化カリウムがフッ化水素に変換される。フッ化水素を含む水溶液は、蒸留塔６において蒸留され、フッ酸が回収される。
図２は、本発明方法の第二の態様の工程系統図である。希薄フッ酸含有排水がフッ素キレート樹脂塔７に通水され、水中のフッ素が樹脂に吸着される。樹脂が飽和したとき通水を停止し、水酸化カリウム水溶液を塔に供給してフッ素を脱離する。フッ化カリウムを含有する脱離液は、蒸発缶２に送られ蒸発濃縮される。発生する蒸気は凝縮器３で冷却され、得られる凝縮水はフッ素吸着塔４に通水されて含有する微量のフッ素が除去され、回収水として利用される。蒸発缶の濃縮液は、酸発生槽５において硫酸が添加され、液中のフッ化カリウムがフッ化水素に変換される。フッ化水素を含む水溶液は、蒸留塔６において蒸留され、フッ酸が回収される。
図３は、本発明方法の第三の態様の工程系統図である。希薄フッ酸含有排水がフッ素キレート樹脂塔７に通水され、水中のフッ素が樹脂に吸着される。樹脂が飽和したとき通水を停止し、水酸化カリウム水溶液を塔に供給してフッ素を脱離する。フッ化カリウムと過剰の水酸化カリウムを含有する脱離液は、混合槽８において濃厚フッ酸含有排水と混合され、濃厚フッ酸含有排水中のフッ酸が水酸化カリウムにより中和されて、フッ化水素に変換される。必要に応じて、混合槽にさらに水酸化カリウム水溶液を添加することができる。混合槽で調製された混合液は、蒸発缶２において蒸発濃縮される。発生する蒸気は凝縮器３で冷却され、得られる凝縮水はフッ素吸着塔４に通水されて含有する微量のフッ素が除去され、回収水として利用される。蒸発缶の濃縮液は、酸発生槽５において硫酸が添加され、液中のフッ化カリウムがフッ化水素に変換される。フッ化水素を含む水溶液は、蒸留塔６において蒸留され、フッ酸が回収される。
【００１１】
【実施例】
以下に、実施例を挙げて本発明をさらに詳細に説明するが、本発明はこれらの実施例によりなんら限定されるものではない。
実施例１
フッ化水素酸［濃度４６．０重量％、試薬、ＪＩＳ Ｋ ８８１９］を水で希釈して、フッ化水素濃度８，４００ｍｇ／Ｌの試験水を調製した。
この試験水１０Ｌに２５重量％水酸化カリウム水溶液１，０００ｇを添加して攪拌し、フッ酸を中和してフッ化カリウム水溶液とした。このフッ化カリウム水溶液から、常圧で水１０，３９０ｇを留去し、釜残として少量の水酸化カリウムを含む４０重量％フッ化カリウム水溶液６１０ｇを得た。
留去された水１０，３９０ｇのフッ素濃度は、３０ｍｇ／Ｌであった。この水をフッ素キレート樹脂［旭エンジニアリング（株）、Ｒｅａｄ−Ｆ］にＳＶ１５ｈ−１で通水処理することにより、フッ素濃度０．５ｍｇ／Ｌの処理水が得られた。
得られた４０重量％フッ化カリウム水溶液に、攪拌しながら９８重量％硫酸２６８ｇを徐々に添加した。このフッ化水素を含む混合液を常圧で蒸留し、共沸混合物として濃度３５重量％のフッ酸１７０ｇ（回収率７１％）を得た。
実施例２
半導体製造工場で発生するフッ素３５ｍｇ／Ｌを含む希薄フッ酸含有排水の処理を行った。
フッ素キレート樹脂［旭エンジニアリング（株）、Ｒｅａｄ−Ｆ］５０ｍＬを充填したカラムに、上記の希薄フッ酸含有排水を７５０ｍＬ／ｈで２５ｈ通水した。カラムから流出した処理水のフッ素濃度は、０．５ｍｇ／Ｌであった。
２５ｈの通水終了後、カラムに０．２１重量％水酸化カリウム水溶液１Ｌを脱着液としてＳＶ５ｈ−１で供給し、フッ素キレート樹脂を再生した。再生廃液として、水酸化カリウム０．１６ｇ、フッ化カリウム２．０ｇを含む水溶液１Ｌが得られた。
この水溶液から常圧で水を留去し、釜残として水酸化カリウム０．１６ｇ、フッ化カリウム２．０ｇ及び水８．０ｇを含む混合物を得た。このフッ化カリウムを含む混合物に、攪拌しながら９８重量％硫酸２．３ｇを徐々に添加したのち、常圧で蒸留し、共沸混合物として濃度３５重量％のフッ酸１．３ｇ（回収率６６％）を得た。
実施例３
半導体製造工場で発生するフッ素３５ｍｇ／Ｌ含む希薄フッ酸含有排水の処理を行った。
フッ素キレート樹脂［旭エンジニアリング（株）、Ｒｅａｄ−Ｆ］５０ｍＬを充填したカラムに、上記の希薄フッ酸含有排水を７５０ｍＬ／ｈで２５ｈ通水した。カラムから流出した処理水のフッ素濃度は、０．５ｍｇ／Ｌであった。
２５ｈの通水終了後、カラムに２．２重量％水酸化カリウム水溶液１Ｌを脱着液としてＳＶ５ｈ−１で供給し、フッ素キレート樹脂を再生した。再生廃液として、水酸化カリウム２０ｇ、フッ化カリウム２．０ｇを含む水溶液１Ｌが得られた。
得られた水溶液１Ｌと、実施例１で調製した試験水０．７６Ｌを混合し、試験水に含まれるフッ酸を中和してフッ化カリウムとした。このフッ化カリウム水溶液から、常圧で水１，７１０ｇを留去し、釜残として少量の水酸化カリウムを含む４０重量％フッ化カリウム水溶液５４ｇを得た。
留去された水１，７１０ｇのフッ素濃度は、３０ｍｇ／Ｌであった。この水をフッ素キレート樹脂［旭エンジニアリング（株）、Ｒｅａｄ−Ｆ］にＳＶ１５ｈ−１で通水処理することにより、フッ素濃度０．５ｍｇ／Ｌの処理水が得られた。
得られた４０重量％フッ化カリウム水溶液に、攪拌しながら９８重量％硫酸２３．５ｇを徐々に添加した。このフッ化水素を含む混合液を常圧で蒸留し、共沸混合物として濃度３５重量％のフッ酸１４．８ｇ（回収率７０％）を得た。
【００１２】
【発明の効果】
本発明のフッ酸の回収方法によれば、フッ化カルシウムを経由することなく、効率的にフッ酸を回収し、さらに水も蒸留水として回収して再利用することができる。
【図面の簡単な説明】
【図１】図１は、本発明方法の第一の態様の工程系統図である。
【図２】図２は、本発明方法の第二の態様の工程系統図である。
【図３】図３は、本発明方法の第三の態様の工程系統図である。
【符号の説明】
１ 中和槽
２ 蒸発缶
３ 凝縮器
４ フッ素吸着塔
５ 酸発生槽
６ 蒸留塔
７ フッ素キレート樹脂塔
８ 混合槽[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for recovering hydrofluoric acid. More specifically, the present invention relates to a method for recovering hydrofluoric acid, which can efficiently recover hydrofluoric acid from hydrofluoric acid-containing wastewater, and can also recover and reuse distilled water.
[0002]
[Prior art]
The hydrofluoric acid-containing wastewater is discharged in various industrial fields such as a metal surface treatment industry, a glass industry, a phosphorus fertilizer manufacturing industry, and a semiconductor manufacturing industry. As a method of treating fluorine contained in wastewater, a method of precipitating and removing water-insoluble calcium fluoride by reaction with a calcium compound such as calcium hydroxide, calcium chloride, or calcium carbonate is widely used. In addition, in order to further reduce the concentration of fluorine in the treated water, a method of performing two-stage aggregation using a calcium compound and an aluminum compound, or using a chelate resin that adsorbs fluorine to remove and remove fluorine in wastewater. Methods have been proposed. For example, an adsorption tower having a zirconium-supported cation-exchange resin as a fluoride ion-removing device that can efficiently remove fluoride ions using a zirconium-supported resin and neutralize and discharge the treatment solution without excess or shortage. To the pH adjusting tower having an OH-type weakly basic anion-exchange resin layer, and supply an acidic adsorption tower treating liquid to neutralize ions. A device for performing replacement has been proposed (Patent Document 1).
Attempts have been made not only to remove fluorine from fluorine-containing wastewater, but also to collect and reuse water. For example, in a system in which low-concentration fluorine-containing water and high-concentration fluorine-containing water are discharged, each fluorine-containing water is efficiently treated to obtain high-purity treated water. A step of contacting with a resin, a step of regenerating the fluorine-adsorbing resin, a step of adding a regenerated waste liquid of the fluorine-adsorbing resin to high-concentration fluorine-containing water, adding a calcium compound, coagulating, and then performing a solid-liquid separation. A method for treating contained water has been proposed (Patent Document 2). Further, as a method of evaporating and concentrating the fluorine-containing wastewater and recovering most of the water as distilled water, a method of adding an aqueous solution of caustic soda or potassium hydroxide to the wastewater of fluorine to suppress the vaporization of hydrofluoric acid accompanying the evaporation of water. Has been proposed (Patent Document 3).
Further, attempts have been made to recover fluorine from fluorine-containing wastewater. For example, rinsing wastewater discharged from the semiconductor manufacturing process is treated with an anion exchange resin, and resin regeneration wastewater is treated at low cost and efficiently in a short time to obtain high-purity treated water, and fluorine is converted into calcium fluoride. As a method that enables efficient recovery and effective reuse, the obtained reclaimed waste liquid is separated into a fluorine-rich reclaimed waste liquid and a fluorine-diluted reclaimed waste liquid, and the fluorine-rich reclaimed waste liquid is passed through a calcium carbonate packed column to remove fluorine. A treatment method for rinsing wastewater in which a diluted regeneration waste liquid is coagulated in a coagulation tank has been proposed (Patent Document 4). In addition, wastewater containing fluoride ions discharged from semiconductor manufacturing processes is treated without using chemicals to obtain wastewater from which fluoride ions have been removed. As a wastewater treatment method that can be recovered inside, the fluoride ion concentration is reduced from the desalting step of removing fluoride ions from wastewater by supplying fluoride ions to wastewater through a condenser and applying a DC voltage to a pair of electrodes A wastewater treatment method for obtaining hydrofluoric acid from a concentration step of obtaining a discharged wastewater and then short-circuiting a pair of electrodes or reversely connecting a DC power supply and recovering the removed fluoride ion component together with the wastewater in the flowing liquid. It has been proposed (Patent Document 5).
[Patent Document 1]
JP-A-8-89949 (pages 2 and 5)
[Patent Document 2]
JP-A-5-92187 (pages 2 and 4)
[Patent Document 3]
JP-A-9-271785 (pages 2 and 6)
[Patent Document 4]
JP-A-6-277663 (pages 2 and 5)
[Patent Document 5]
JP-A-2001-113284 (page 2, page 6-7)
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for recovering hydrofluoric acid, which can efficiently recover hydrofluoric acid from hydrofluoric acid-containing wastewater, and can also recover and reuse distilled water. .
[0004]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, after converting hydrogen fluoride in hydrofluoric acid-containing wastewater into potassium fluoride, the potassium fluoride was concentrated by evaporation to a potassium fluoride concentration of 15% by weight or more. By generating a concentrated solution having a solubility concentration or less and recovering hydrofluoric acid from the obtained concentrated solution, it is possible to efficiently recover hydrofluoric acid.Furthermore, when the concentration of hydrofluoric acid-containing wastewater is low, Is brought into contact with a fluorine chelating resin, and then a potassium hydroxide aqueous solution is supplied to the chelating resin as a desorbing solution to obtain a potassium fluoride-containing solution, and the solution is concentrated and treated in the same manner, or the obtained fluorine is obtained. After mixing the potassium fluoride-containing liquid and the concentrated hydrofluoric acid-containing wastewater, it was found that by performing the same concentration and treatment, it was possible to efficiently recover hydrofluoric acid. This has led to the formation.
That is, the present invention
(1) A basic potassium compound is added to a hydrofluoric acid-containing wastewater to convert hydrogen fluoride into potassium fluoride, and then concentrated by evaporation to produce a concentrated solution having a potassium fluoride concentration of 15% by weight or more and a solubility concentration of not more than A method for recovering hydrofluoric acid from hydrofluoric acid-containing wastewater, comprising recovering hydrofluoric acid from the obtained concentrated liquid,
(2) Contacting the dilute hydrofluoric acid-containing wastewater with a fluorine chelating resin, then supplying a potassium hydroxide aqueous solution as a desorbing solution to the chelating resin to which fluorine has been adsorbed to obtain a potassium fluoride-containing liquid, and then evaporating and concentrating the fluorine-containing liquid A method for recovering hydrofluoric acid from hydrofluoric acid-containing wastewater, comprising: producing a concentrated solution having a potassium fluoride concentration of 15% by weight or more and a solubility concentration or less, and recovering hydrofluoric acid from the obtained concentrated solution.
(3) The diluted hydrofluoric acid-containing wastewater is brought into contact with a fluorine chelate resin, and then an aqueous solution of potassium hydroxide is supplied as a desorbing solution to the chelate resin to which fluorine has been adsorbed to obtain a potassium fluoride-containing solution. After mixing the liquid and the concentrated hydrofluoric acid-containing wastewater, it is concentrated by evaporation to produce a concentrated solution having a potassium fluoride concentration of 15% by weight or more and a solubility concentration of less than the concentration, and hydrofluoric acid is recovered from the obtained concentrated solution. A method for recovering hydrofluoric acid from hydrofluoric acid-containing wastewater, and
(4) The production of hydrofluoric acid from potassium fluoride by adding sulfuric acid to the concentrated solution, and the production of hydrofluoric acid. Collection method,
Is provided.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
In the first embodiment of the method of the present invention, a basic potassium compound is added to a hydrofluoric acid-containing wastewater to convert hydrogen fluoride into potassium fluoride, and then concentrated by evaporation to a potassium fluoride concentration of 15% by weight or more and a solubility concentration of 15% by weight or more. The following concentrated solution is produced, and hydrofluoric acid is recovered from the obtained concentrated solution.
In the second embodiment of the method of the present invention, a diluted hydrofluoric acid-containing wastewater is brought into contact with a fluorine chelating resin, and then an aqueous potassium hydroxide solution is supplied as a desorbing solution to the chelating resin having adsorbed fluorine to obtain a potassium fluoride-containing liquid. After that, the solution is evaporated and concentrated to produce a concentrated solution having a potassium fluoride concentration of 15% by weight or more and a solubility concentration of less than the solubility concentration, and hydrofluoric acid is recovered from the obtained concentrated solution.
In the third embodiment of the method of the present invention, a dilute hydrofluoric acid-containing wastewater is brought into contact with a fluorine chelate resin, and then a potassium hydroxide aqueous solution is supplied as a desorption solution to the chelate resin having fluorine adsorbed thereon to obtain a potassium fluoride-containing liquid. After mixing the obtained potassium fluoride-containing liquid and the concentrated hydrofluoric acid-containing wastewater, the mixture is evaporated and concentrated to produce a concentrated liquid having a potassium fluoride concentration of 15% by weight or more and a solubility concentration of not more than the obtained concentrated liquid. Collect hydrofluoric acid.
In the method of the present invention, sulfuric acid is added to a concentrated solution having a potassium fluoride concentration of 15% by weight or more and a solubility concentration or less to generate hydrofluoric acid from potassium fluoride and recover the generated hydrofluoric acid.
[0006]
The hydrofluoric acid-containing wastewater to which the method of the present invention is applied is not particularly limited, and examples thereof include an etching wastewater and a rinse wastewater generated in a semiconductor manufacturing factory, a wastewater from a metal surface treatment factory, a glass factory, and the like. The method of the present invention can be particularly suitably applied to a factory in which both concentrated hydrofluoric acid-containing wastewater and dilute hydrofluoric acid-containing wastewater are discharged. The concentrated hydrofluoric acid-containing wastewater is wastewater having a hydrogen fluoride concentration of 50 mg / L or more, and the dilute hydrofluoric acid-containing wastewater is wastewater having a hydrogen fluoride concentration of less than 50 mg / L.
In the method of the present invention, a basic potassium compound is added to the hydrofluoric acid-containing wastewater to convert hydrogen fluoride into potassium fluoride and then concentrate by evaporation. Examples of the basic potassium compound to be used include potassium hydroxide, potassium carbonate, potassium hydrogen carbonate and the like. When potassium hydroxide is used, hydrogen fluoride becomes potassium fluoride according to the following formula.
HF + KOH → KF + H 2 O
Since the hydrofluoric acid-containing wastewater has a low pH, direct evaporation of the wastewater causes problems such as corrosion of the apparatus and transfer of hydrogen fluoride to the vapor side. After the hydrogen fluoride in the waste water is converted to potassium fluoride and then evaporated and concentrated, the adverse effect of the hydrogen fluoride can be prevented.
As a neutralizing agent for hydrofluoric acid, a sodium compound such as sodium hydroxide may be considered in addition to a potassium compound such as potassium hydroxide. When neutralized with sodium hydroxide, hydrogen fluoride becomes sodium fluoride, and when neutralized with potassium hydroxide, hydrogen fluoride becomes potassium fluoride. When water is evaporated from the neutralized wastewater, sodium fluoride or potassium fluoride in the wastewater is concentrated, and when the solubility exceeds the solubility, a salt is precipitated. When the salt is precipitated, the efficiency of the evaporator is reduced and obstacles such as scaling occur. Therefore, it is necessary to keep the evaporation concentration below the solubility concentration of the salt. Solubility of sodium hydroxide in water is 4.5% by weight at 60 ° C., whereas solubility of potassium fluoride in water is 58.7% by weight at 60 ° C. Therefore, when hydrogen fluoride is converted to potassium fluoride and evaporated, the concentration can be greatly increased as compared with the case of converting sodium fluoride to sodium fluoride. As a solution containing high-concentration potassium fluoride, hydrofluoric acid is efficiently used. Can be recovered.
[0007]
In the method of the present invention, a concentrated solution having a potassium fluoride concentration of 15% by weight or more and a solubility concentration of not more than a concentration, and more preferably a concentrated solution having a potassium fluoride concentration of 20% to 50% by weight is produced by evaporation and concentration. If the concentration of potassium fluoride is less than 15% by weight, the efficiency of recovering hydrofluoric acid may decrease. In the method of the present invention, the concentration can be increased to the solubility of potassium fluoride at the evaporation temperature. However, when the concentration of potassium fluoride in the concentrated solution is 50% by weight or less, the salt is not precipitated even when the temperature of the concentrated solution is lowered to 25 ° C., so that the operation is easy.
There is no particular limitation on the evaporator used in the method of the present invention, and examples thereof include a submerged combustion system, a natural circulation type immersion tube type, a natural circulation type horizontal tube type, a vertical short tube type, a vertical long tube rising film type, and a horizontal tube falling film. Evaporating devices such as a mold, a vertical long tube descending film type, a forced circulation type horizontal tube type, a forced circulation type vertical tube type, a coil type, a stirring film type, a centrifugal type thin film type, a plate type, and a flash evaporation type. . In the method of the present invention, there is no particular limitation on the arrangement and operation method of the evaporator, and examples thereof include a single can, a vapor compression method, a multiple effect method, and a multi-stage flash evaporation method.
In the method of the present invention, the steam generated from the evaporator of the aqueous potassium fluoride solution can be cooled and discharged as condensed water. Since the hydrofluoric acid in the wastewater is potassium fluoride, it hardly moves to the vapor side like hydrogen fluoride, and the fluorine contained in the condensed water is very small. If necessary, the fluorine in the condensed water can be completely removed using a fluorine adsorption resin, a calcium carbonate packed tower, a reverse osmosis membrane device, a continuous deionization device, or the like. The condensed water can be reused or discharged.
In the method of the present invention, hydrofluoric acid is recovered from a concentrated liquid containing 15% by weight or more of potassium fluoride obtained by evaporation and concentration. There is no particular limitation on the method for recovering hydrofluoric acid. For example, sulfuric acid can be added to a concentrated solution, and potassium fluoride can be converted to hydrogen fluoride according to the following formula.
2KF + H 2 SO 4 → 2HF + K 2 SO 4
The amount of sulfuric acid to be added is preferably at least a reaction equivalent to potassium fluoride in the concentrated solution, more preferably 1.2 to 2 equivalents. The concentrated liquid to which sulfuric acid is added and containing hydrogen fluoride and potassium sulfate is heated to, for example, 60 to 100 ° C. to vaporize hydrogen fluoride in the liquid, and then to remove the gas containing hydrogen fluoride into an absorption tower. And hydrogen-fluoride can be absorbed in water by gas-liquid contact with water. The hydrogen fluoride absorbing liquid can be collected and reused.
[0008]
In the second embodiment of the method of the present invention, the dilute hydrofluoric acid-containing wastewater is brought into contact with a fluorine chelate resin, and then the potassium chelate resin to which fluorine has been adsorbed is supplied as an aqueous solution of potassium hydroxide as a desorbing solution, thereby forming a potassium fluoride-containing liquid. obtain. A concentrated aqueous solution of potassium fluoride can be obtained by contacting the diluted hydrofluoric acid-containing waste water with a chelating resin to adsorb fluorine and desorbing the aqueous solution using a potassium hydroxide aqueous solution. Heat energy for evaporating a large amount of water can be reduced as compared with the case of evaporating and concentrating a dilute aqueous solution of potassium fluoride obtained by adding potassium hydroxide to dilute hydrofluoric acid-containing wastewater. There is no particular limitation on the fluorine chelate resin used, for example, cerium, hafnium, titanium, zirconium, iron, a resin adsorbing a metal ion forming a complex compound with a fluoride ion such as aluminum, a chelate resin having a phosphomethylamino group, and the like. Can be mentioned.
There is no particular limitation on the method of bringing the diluted hydrofluoric acid-containing wastewater into contact with the fluorine chelate resin. For example, the dilute hydrofluoric acid-containing wastewater can be passed through a packed tower filled with the fluorine chelate resin. It is preferred that the fluorine ions be adsorbed on the fluorine chelate resin and, when the adsorption ability of the resin is saturated, the desorption liquid be passed through a packed tower to desorb the fluorine adsorbed on the resin. The fluorine in the desorbed liquid is more concentrated than in the raw wastewater. By using an aqueous solution of potassium hydroxide as the desorption solution, the fluorine in the desorption solution becomes potassium fluoride. By evaporating and concentrating the desorbed solution, a concentrated solution having a potassium fluoride concentration of 15% by weight or more and a solubility concentration or less is obtained, and hydrofluoric acid is recovered from the concentrated solution.
[0009]
In the third aspect of the present invention, contacting the diluted hydrofluoric acid-containing waste water with a fluorine chelate resin, and then supplying a potassium hydroxide aqueous solution to the chelate resin having adsorbed fluorine as a desorption liquid to obtain a potassium fluoride-containing liquid, After mixing the obtained potassium fluoride-containing liquid and the concentrated hydrofluoric acid-containing wastewater, the mixture is evaporated and concentrated. As in a semiconductor manufacturing plant, when concentrated hydrofluoric acid-containing wastewater such as etching wastewater and dilute hydrofluoric acid-containing wastewater such as rinsing wastewater are generated in the same place, the method of this embodiment can be preferably used. . A concentrated aqueous solution of potassium fluoride can be obtained by contacting the diluted hydrofluoric acid-containing waste water with a chelating resin to adsorb fluorine and desorbing the aqueous solution using a potassium hydroxide aqueous solution. There is no particular limitation on the fluorine chelate resin used, for example, cerium, hafnium, titanium, zirconium, iron, a resin adsorbing a metal ion forming a complex compound with a fluoride ion such as aluminum, a chelate resin having a phosphomethylamino group, and the like. Can be mentioned. For desorption of the adsorbed fluorine, potassium hydroxide in an amount equivalent to or more than fluorine is usually used, so that the potassium fluoride-containing liquid obtained by the desorption contains an excess of potassium hydroxide. By mixing the potassium fluoride-containing liquid with the concentrated hydrofluoric acid-containing wastewater, potassium hydroxide contained in the potassium fluoride-containing liquid can be used for neutralizing hydrofluoric acid in the concentrated hydrofluoric acid-containing wastewater.
[0010]
FIG. 1 is a process flow chart of the first embodiment of the method of the present invention. In the neutralization tank 1, an aqueous solution of potassium hydroxide is added to the hydrofluoric acid-containing wastewater to convert hydrogen fluoride into potassium fluoride. The aqueous potassium fluoride solution is evaporated and concentrated in the evaporator 2. The generated steam is cooled by the condenser 3, and the obtained condensed water is passed through the fluorine adsorption tower 4 to remove a small amount of contained fluorine and used as recovered water. Sulfuric acid is added to the concentrated liquid in the evaporator in the acid generating tank 5, and potassium fluoride in the liquid is converted into hydrogen fluoride. The aqueous solution containing hydrogen fluoride is distilled in the distillation column 6 to recover hydrofluoric acid.
FIG. 2 is a process flow chart of the second embodiment of the method of the present invention. The dilute hydrofluoric acid-containing wastewater is passed through the fluorine
FIG. 3 is a process flow chart of the third embodiment of the method of the present invention. The dilute hydrofluoric acid-containing wastewater is passed through the fluorine
[0011]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Example 1
Hydrofluoric acid [concentration 46.0% by weight, reagent, JIS K 8819] was diluted with water to prepare test water having a hydrogen fluoride concentration of 8,400 mg / L.
To 10 L of this test water, 1,000 g of a 25% by weight aqueous solution of potassium hydroxide was added and stirred to neutralize hydrofluoric acid to obtain an aqueous solution of potassium fluoride. From this aqueous potassium fluoride solution, 10,390 g of water was distilled off at normal pressure to obtain 610 g of a 40% by weight aqueous potassium fluoride solution containing a small amount of potassium hydroxide as a bottom residue.
The fluorine concentration of 10,390 g of the distilled water was 30 mg / L. This water was passed through a fluorine chelate resin [Asahi Engineering Co., Ltd., Read-F] at SV15h- 1 to obtain treated water having a fluorine concentration of 0.5 mg / L.
268 g of 98% by weight sulfuric acid was gradually added to the obtained 40% by weight aqueous potassium fluoride solution with stirring. The mixed solution containing hydrogen fluoride was distilled at normal pressure to obtain 170 g of hydrofluoric acid having a concentration of 35% by weight (recovery rate: 71%) as an azeotropic mixture.
Example 2
Waste water containing diluted hydrofluoric acid containing 35 mg / L of fluorine generated in a semiconductor manufacturing plant was treated.
The diluted hydrofluoric acid-containing wastewater was passed through a column filled with 50 mL of a fluorine chelate resin [Asahi Engineering Co., Ltd., Read-F] at 750 mL / h for 25 h. The fluorine concentration of the treated water flowing out of the column was 0.5 mg / L.
After the completion of 25 hours of water passage, 1 L of a 0.21% by weight aqueous solution of potassium hydroxide was supplied to the column as a desorbing liquid at an SV of 5 h- 1 to regenerate the fluorine chelate resin. As a regeneration waste liquid, 1 L of an aqueous solution containing 0.16 g of potassium hydroxide and 2.0 g of potassium fluoride was obtained.
Water was distilled off from the aqueous solution at normal pressure to obtain a mixture containing 0.16 g of potassium hydroxide, 2.0 g of potassium fluoride, and 8.0 g of water as a residue. 2.3 g of 98% by weight sulfuric acid was gradually added to the mixture containing potassium fluoride with stirring, and then distilled under normal pressure to obtain 1.3 g of hydrofluoric acid having a concentration of 35% by weight as an azeotropic mixture (recovery rate: 66%). %).
Example 3
Waste water containing diluted hydrofluoric acid containing 35 mg / L of fluorine generated in a semiconductor manufacturing plant was treated.
The diluted hydrofluoric acid-containing wastewater was passed through a column filled with 50 mL of a fluorine chelate resin [Asahi Engineering Co., Ltd., Read-F] at 750 mL / h for 25 h. The fluorine concentration of the treated water flowing out of the column was 0.5 mg / L.
After 25 hours of water flow, 1 L of a 2.2% by weight aqueous solution of potassium hydroxide was supplied to the column as a desorbing liquid at SV 5 h -1 to regenerate the fluorine chelate resin. As a recycling waste liquid, 1 L of an aqueous solution containing 20 g of potassium hydroxide and 2.0 g of potassium fluoride was obtained.
1 L of the obtained aqueous solution and 0.76 L of the test water prepared in Example 1 were mixed, and hydrofluoric acid contained in the test water was neutralized to obtain potassium fluoride. From this aqueous solution of potassium fluoride, 1,710 g of water was distilled off at normal pressure to obtain 54 g of a 40% by weight aqueous solution of potassium fluoride containing a small amount of potassium hydroxide as a residue.
The fluorine concentration of 1,710 g of the distilled water was 30 mg / L. By passing this water through a fluorine chelate resin [Asahi Engineering Co., Ltd., Read-F] at SV15h- 1 , treated water having a fluorine concentration of 0.5 mg / L was obtained.
23.5 g of 98% by weight sulfuric acid was gradually added to the obtained 40% by weight aqueous potassium fluoride solution with stirring. The mixed solution containing hydrogen fluoride was distilled at normal pressure to obtain 14.8 g of hydrofluoric acid having a concentration of 35% by weight (recovery rate: 70%) as an azeotropic mixture.
[0012]
【The invention's effect】
According to the method for recovering hydrofluoric acid of the present invention, hydrofluoric acid can be efficiently recovered without passing through calcium fluoride, and water can be recovered as distilled water and reused.
[Brief description of the drawings]
FIG. 1 is a process flow chart of a first embodiment of the method of the present invention.
FIG. 2 is a process flow chart of a second embodiment of the method of the present invention.
FIG. 3 is a process flow chart of a third embodiment of the method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Neutralization tank 2 Evaporator 3 Condenser 4 Fluorine adsorption tower 5 Acid generation tank 6
Claims (4)
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2019536721A (en) * | 2016-10-04 | 2019-12-19 | ハネウェル・インターナショナル・インコーポレーテッドＨｏｎｅｙｗｅｌｌ Ｉｎｔｅｒｎａｔｉｏｎａｌ Ｉｎｃ． | Process for recovering hydrogen fluoride from a hydrogen fluoride polymer composition |
| CN111354637A (en) * | 2020-02-28 | 2020-06-30 | 通威太阳能(眉山)有限公司 | Method for washing graphite boat by cyclic utilization of hydrofluoric acid |
| CN112456443A (en) * | 2020-12-19 | 2021-03-09 | 蚌埠学院 | Recovery processing method and recovery processing device for glass etching waste liquid |
| CN112939307A (en) * | 2020-12-25 | 2021-06-11 | 宿迁思睿屹新材料有限公司 | Treatment method of chemical wastewater in 2,6 acid production |
| CN113045089A (en) * | 2021-03-15 | 2021-06-29 | 盛隆资源再生（无锡）有限公司 | Method for refining and purifying etching waste liquid |
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| JPH0592187A (en) * | 1991-10-01 | 1993-04-16 | Kurita Water Ind Ltd | Treatment of fluorine-containing water |
| JP2002029706A (en) * | 2000-07-10 | 2002-01-29 | Daikin Ind Ltd | Device and method for manufacturing hydrogen fluoride |
| JP2002331292A (en) * | 2001-05-08 | 2002-11-19 | Sasakura Engineering Co Ltd | Fluoric acid-containing wastewater treatment method and apparatus |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH0592187A (en) * | 1991-10-01 | 1993-04-16 | Kurita Water Ind Ltd | Treatment of fluorine-containing water |
| JP2002029706A (en) * | 2000-07-10 | 2002-01-29 | Daikin Ind Ltd | Device and method for manufacturing hydrogen fluoride |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2019536721A (en) * | 2016-10-04 | 2019-12-19 | ハネウェル・インターナショナル・インコーポレーテッドＨｏｎｅｙｗｅｌｌ Ｉｎｔｅｒｎａｔｉｏｎａｌ Ｉｎｃ． | Process for recovering hydrogen fluoride from a hydrogen fluoride polymer composition |
| CN111354637A (en) * | 2020-02-28 | 2020-06-30 | 通威太阳能(眉山)有限公司 | Method for washing graphite boat by cyclic utilization of hydrofluoric acid |
| CN112456443A (en) * | 2020-12-19 | 2021-03-09 | 蚌埠学院 | Recovery processing method and recovery processing device for glass etching waste liquid |
| CN112456443B (en) * | 2020-12-19 | 2023-12-05 | 蚌埠学院 | Recovery processing method and recovery processing device for glass etching waste liquid |
| CN112939307A (en) * | 2020-12-25 | 2021-06-11 | 宿迁思睿屹新材料有限公司 | Treatment method of chemical wastewater in 2,6 acid production |
| CN113045089A (en) * | 2021-03-15 | 2021-06-29 | 盛隆资源再生（无锡）有限公司 | Method for refining and purifying etching waste liquid |
| CN113045089B (en) * | 2021-03-15 | 2023-04-18 | 盛隆资源再生（无锡）有限公司 | Method for refining and purifying etching waste liquid |
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