JP2003260472A - Treatment method for fluorine-containing water - Google Patents
Treatment method for fluorine-containing waterInfo
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- JP2003260472A JP2003260472A JP2002067222A JP2002067222A JP2003260472A JP 2003260472 A JP2003260472 A JP 2003260472A JP 2002067222 A JP2002067222 A JP 2002067222A JP 2002067222 A JP2002067222 A JP 2002067222A JP 2003260472 A JP2003260472 A JP 2003260472A
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- Prior art keywords
- fluorine
- water
- containing water
- treated water
- added
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Removal Of Specific Substances (AREA)
- Water Treatment By Sorption (AREA)
Abstract
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、フッ素含有水の処
理方法に関する。さらに詳しくは、本発明は、フッ素含
有水を処理して、効率的に極めて低濃度までフッ素を除
去することができるフッ素含有水の処理方法に関する。
【０００２】
【従来の技術】フッ素は、フッ酸含有洗浄液やバッファ
ードフッ酸含有エッチング剤を使用する半導体製造工程
からの排水や、金属精錬、ガラス、窯業、化学工業など
からの排水、排煙脱硫排水、地下水などに含まれる。フ
ッ酸は腐食性が強く、管渠を損傷し、フッ素は、終末処
理場では生物処理機能を阻害するので、排水中のフッ素
を低濃度まで除去することが求められる。水中のフッ素
を除去する方法として、水に水酸化カルシウム、塩化カ
ルシウムなどのカルシウム化合物を添加してフッ化カル
シウム（ＣａＦ2）を生成させ沈殿分離する方法、水に
ポリ塩化アルミニウム、硫酸バンドなどのアルミニウム
化合物を添加し、水中で高分子量化したアルミニウム化
合物にフッ素を吸着沈殿させる方法、フッ素吸着樹脂に
フッ素を吸着させる方法などが知られている。カルシウ
ム化合物又はアルミニウム化合物を用いる１段処理法の
フッ素除去では、フッ素を十分に除去することはでき
ず、処理水中に１０〜３０mg／Ｌ程度のフッ素が残留す
る。処理水中のフッ素濃度をより低減するために、カル
シウム化合物によりフッ素を除去したのち、アルミニウ
ム化合物を用いてフッ素除去を行う２段処理法も知られ
ている。この場合、通常は処理水のフッ素濃度は３〜５
mg／Ｌが限度であり、それ以上にフッ素を除去するため
には、アルミニウム化合物の添加量を著しく増大する必
要があり、現実的でない。フッ素吸着樹脂によるフッ素
除去では、樹脂への給水のフッ素濃度が高いと、吸着能
を短時間で消耗し、再生頻度が大きくなるという問題が
あり、通常はフッ素濃度の希薄なフッ素含有水に適用す
る。上述のように、カルシウム化合物による沈殿とアル
ミニウム化合物による沈殿との２段処理法でも処理水の
フッ素濃度には限界があることから、２段処理法の後段
にフッ素吸着樹脂を配置することも試みられているが、
必ずしも処理水質は改善されない。
【０００３】
【発明が解決しようとする課題】本発明は、フッ素含有
水を処理して、効率的に極めて低濃度までフッ素を除去
することができるフッ素含有水の処理方法を提供するこ
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】本発明者は、上記の課題
を解決すべく鋭意研究を重ねた結果、カルシウム化合物
とアルミニウム化合物を用いる２段処理法の後段にフッ
素吸着樹脂を配置しても処理水中のフッ素濃度を十分に
低減できない原因は、フッ素とアルミニウムが錯体を形
成し、この錯体がフッ素吸着樹脂に吸着されないことに
あることを突きとめ、アルミニウム化合物の代わりに鉄
塩を用いて２段処理を行い、この処理水をフッ素吸着体
と接触させることにより、最終処理水のフッ素濃度を１
mg／Ｌ以下に低減し得ることを見いだし、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、フッ素含有水にカルシウム化合物を添加し、固液分
離する第１工程と、第１工程処理水に鉄塩を添加し、固
液分離する第２工程と、第２工程処理水をフッ素吸着体
と接触させる第３工程とからなることを特徴とするフッ
素含有水の処理方法を提供するものである。
【０００５】
【発明の実施の形態】本発明方法は、フッ素含有水にカ
ルシウム化合物を添加し、固液分離する第１工程と、第
１工程処理水に鉄塩を添加し、固液分離する第２工程
と、第２工程処理水をフッ素吸着体と接触させる第３工
程とからなる。本発明方法を適用するフッ素含有水のフ
ッ素濃度に特に制限はなく、例えば、フッ素濃度５０〜
３０,０００mg／Ｌのフッ素含有水を処理して、フッ素
濃度１mg／Ｌ以下の処理水を得ることができる。本発明
方法においては、第１工程において、フッ素含有水にカ
ルシウム化合物を添加する。添加するカルシウム化合物
に特に制限はなく、例えば、水酸化カルシウム、酸化カ
ルシウム、塩化カルシウム、硝酸カルシウムなどを挙げ
ることができる。カルシウム化合物の添加量に特に制限
はないが、フッ素含有水中のフッ素イオン１モルに対し
てカルシウムイオンとして０.５〜３モルであることが
好ましく、１〜２.５モルであることがより好ましい。
カルシウム化合物の添加量が、フッ素イオン１モルに対
してカルシウムイオンとして０.５モル未満であると、
フッ化カルシウム（ＣａＦ2）を形成するためのカルシ
ウムイオンが不足し、処理水中のフッ素濃度が十分に低
下しないおそれがある。カルシウム化合物の添加量が、
フッ素イオン１モルに対してカルシウムイオンとして３
モルを超えると、溶解度積から水中のフッ素イオン濃度
を低下させる効果が相対的に小さくなり、カルシウム化
合物の使用量がいたずらに嵩むおそれがある。
【０００６】本発明方法において、フッ素含有水にカル
シウム化合物を添加したのち、フッ素含有水のpHを６〜
１１に調整することが好ましく、６.５〜１０に調整す
ることがより好ましい。pHが６未満であっても、１１を
超えても、フッ素の除去率が低下するおそれがある。カ
ルシウム化合物の添加方法とpH調整方法に特に制限はな
く、例えば、フッ素含有水を混合槽に導入し、カルシウ
ム化合物とpH調整剤を添加して混合することができる。
フッ素含有水のフッ素濃度が高く、カルシウム化合物と
して水酸化カルシウムを用いた場合は、水酸化カルシウ
ム粒子の表面がフッ化カルシウムに覆われて反応速度が
遅くなるので、十分な撹拌を与えることが好ましい。混
合槽における滞留時間は、１分〜５時間であることが好
ましく、５分〜１時間であることがより好ましい。本発
明方法において、カルシウム化合物を添加し、pHを調整
して、フッ化カルシウムを沈殿させたフッ素含有水は、
凝集槽に移送して凝集剤を添加し、フッ化カルシウムの
沈殿を凝集させることが好ましい。添加する凝集剤に特
に制限はないが、ポリアクリルアミド部分加水分解物、
アクリルアミドとアクリル酸ナトリウムの共重合体など
の高分子凝集剤を好適に用いることができる。凝集剤の
添加量に特に制限はないが、０.０１〜１０mg／Ｌであ
ることが好ましく、０.１〜５mg／Ｌであることがより
好ましい。凝集槽における滞留時間は、１分〜５時間で
あることが好ましく、５分〜１時間であることがより好
ましい。本発明方法において、第１工程における固液分
離方法に特に制限はなく、例えば、重力沈殿、遠心沈殿
などの沈殿法、精密ろ過膜、限外ろ過膜、逆浸透膜など
を用いる膜分離法などを挙げることができる。本発明方
法によれば、フッ素濃度８〜３０mgの第１工程処理水を
得ることができる。
【０００７】本発明方法においては、第２工程におい
て、第１工程処理水に鉄塩を添加する。第１工程処理水
は、凝集槽に移送して鉄塩を添加することが好ましい。
添加する鉄塩に特に制限はなく、例えば、塩化第一鉄、
硫酸第一鉄などの第一鉄塩、塩化第二鉄、硫酸第二鉄な
どの第二鉄塩、ポリ塩酸鉄、ポリ硫酸鉄などのポリ鉄な
どを挙げることができる。鉄塩の添加量に特に制限はな
いが、鉄として第１工程処理水中に存在するフッ素イオ
ンの３重量倍以上であることが好ましく、５重量倍以上
であることがより好ましい。鉄塩の添加量が、鉄として
フッ素イオンの３重量倍未満であると、フッ素の除去が
不十分となるおそれがある。第２工程における被処理水
のpHに特に制限はなく、通常はpHの調整を必要としない
が、中性付近であることが好ましい。第１工程処理水に
鉄塩を添加すると、水酸化鉄のフロックが生成するとと
もに、フッ素が共沈現象で沈降するので、フッ素が含ま
れる水酸化鉄のフロックを固液分離する。第２工程にお
ける固液分離方法に特に制限はなく、例えば、重力沈
殿、遠心沈殿などの沈殿法、アンスラサイト、砂などを
用いるろ過法、精密ろ過膜、限外ろ過膜、逆浸透膜など
を用いる膜分離法などを挙げることができる。これらの
固液分離法は、１種を単独で用いることができ、あるい
は、２種以上を組み合わせて用いることもできる。本発
明方法によれば、フッ素濃度３〜８mg／Ｌの第２工程処
理水を得ることができる。
【０００８】本発明方法においては、第３工程におい
て、第２工程処理水をフッ素吸着体と接触させる。第２
工程の固液分離に沈殿法のみを用いた場合は、第２工程
処理水中に含まれる微細な懸濁物質をろ過器などにより
除去し、懸濁物質によるフッ素吸着体の目詰まりを防止
することが好ましい。第２工程処理水と接触させるフッ
素吸着体としては、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、ランタニドな
どの金属イオンを吸着したフッ素吸着樹脂や、活性炭、
活性アルミナ、含水酸化チタン、ゼオライト、マグネシ
アなどの吸着剤などを挙げることができる。フッ素吸着
体と接触させる第２工程処理水は、接触させるフッ素吸
着体の特性に応じて、好適なpHに調整することが好まし
い。例えば、市販のフッ素吸着樹脂［旭エンジニアリン
グ(株)、リードＦ］を用いる場合は、pH３〜５に調整す
ることが好ましい。第２工程処理水とフッ素吸着体を接
触させる方法に特に制限はなく、例えば、フッ素吸着樹
脂を充填したフッ素吸着樹脂塔に、第２工程処理水を通
水することができる。通水速度に特に制限はないが、Ｓ
Ｖ１〜５０ｈ-1であることが好ましく、ＳＶ１０〜３０
ｈ-1であることがより好ましい。フッ素吸着樹脂塔は、
必要に応じて、吸着処理を停止し、再生剤を通液して再
生処理することが好ましい。再生剤は、フッ素吸着樹脂
の特性に応じて適宜選択することができるが、例えば、
水酸化ナトリウム、水酸化カリウム、炭酸ナトリウムな
どの水溶液や、塩酸などを挙げることができる。本発明
方法によれば、第３工程を経た処理水のフッ素濃度は、
１mg／Ｌ以下となる。
【０００９】図１は、本発明方法の実施の一態様の工程
系統図である。フッ素含有水を混合槽１に導入し、カル
シウム化合物とpH調整剤を添加し、撹拌混合することに
より水中に含まれるフッ素の大部分をフッ素カルシウム
として沈殿させる。フッ素カルシウムが沈殿したフッ素
含有水は、凝集槽２へ送り、凝集剤を添加して、フッ化
カルシウムの沈殿を凝集フロックとする。凝集フロック
となったフッ化カルシウムの沈殿を、沈殿槽３で沈降分
離し、上澄水として第１工程処理水を得る。第１工程処
理水を凝集槽４に移送し、鉄塩を添加することにより、
水酸化鉄のフロックを生成させ、残存するフッ素を共沈
現象で沈降させる。フッ素が共沈した水酸化鉄のフロッ
クは、沈殿槽５で沈降分離し、上澄水として第２工程処
理水を得る。第２工程処理水は、ろ過器６に通水して混
在する微細な懸濁物質を除去したのち、pH調整槽７に導
入し、pH調整剤を添加して、使用するフッ素吸着樹脂に
適切なpHに調整する。pH調整を終えた被処理水を、フッ
素吸着樹脂塔８に通水して、フッ素濃度１mg／Ｌ以下の
処理水を得る。本発明のフッ素含有水の処理方法によれ
ば、フッ素吸着体に吸着されにくいフッ素とアルミニウ
ムの錯体が生成しないので、カルシウム化合物と鉄塩を
用いる２段処理法で得られる処理水をフッ素吸着体に接
触させ、フッ素濃度が十分に低い最終処理水を容易に得
ることができる。
【００１０】
【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
フッ素９５mg／Ｌを含有するpH４の排水に、水酸化カル
シウム７００mg／Ｌを添加し、硫酸を用いてpH７.５に
調整し、撹拌しながら２０分間反応させた。次いで、ポ
リアクリルアミド部分加水分解物１mg／Ｌを添加し、沈
殿分離した。上澄水のフッ素濃度は、１５mg／Ｌであっ
た。この上澄水に、塩化第二鉄１,０００mg／Ｌを添加
し、撹拌しながら２０分間反応させ、沈殿分離した。得
られた上澄水のフッ素濃度は、３mg／Ｌであった。この
上澄水を砂ろ過したのち、硫酸を用いてpHを４に調整
し、フッ素吸着樹脂［旭エンジニアリング(株)、リード
Ｆ］を充填したフッ素吸着樹脂塔に、ＳＶ２５ｈ-1で通
水した。フッ素吸着樹脂塔から流出する処理水のフッ素
濃度は、１.０mg／Ｌであった。
比較例１
塩化第二鉄の代わりにポリ塩化アルミニウムを添加した
以外は、実施例１と同様にして、フッ素含有水の処理を
行った。ポリ塩化アルミニウムを添加して得られた上澄
水のフッ素濃度は、８mg／Ｌであった。また、フッ素吸
着樹脂塔から流出する処理水のフッ素濃度は３.５mg／
Ｌであった。実施例１及び比較例１の結果を、第１表に
示す。
【００１１】
【表１】
【００１２】
【発明の効果】本発明のフッ素含有水の処理方法によれ
ば、フッ素吸着体に吸着されにくいフッ素とアルミニウ
ムの錯体が生成しないので、カルシウム化合物と鉄塩を
用いる２段処理法で得られる処理水をフッ素吸着体に接
触させ、フッ素濃度が十分に低い最終処理水を容易に得
ることができる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating fluorine-containing water. More specifically, the present invention relates to a method for treating fluorine-containing water, which can efficiently remove fluorine to a very low concentration by treating the fluorine-containing water. [0002] Fluorine is a wastewater from a semiconductor manufacturing process using a cleaning solution containing hydrofluoric acid or an etching agent containing buffered hydrofluoric acid, a wastewater from metal refining, glass, ceramics, the chemical industry, etc., and a flue gas. Included in desulfurization drainage and groundwater. Hydrofluoric acid is highly corrosive and damages sewers. Fluorine impairs biological treatment functions in terminal treatment plants, so it is required to remove fluorine in wastewater to a low concentration. As a method of removing fluorine in water, a method of adding calcium compounds such as calcium hydroxide and calcium chloride to water to generate calcium fluoride (CaF 2 ) and separating by precipitation, a method of removing polyaluminum chloride, a sulfate band and the like in water. There are known a method in which an aluminum compound is added and fluorine is adsorbed and precipitated on an aluminum compound having a high molecular weight in water, and a method in which fluorine is adsorbed on a fluorine-adsorbing resin. Fluorine cannot be sufficiently removed by the one-stage treatment method using a calcium compound or an aluminum compound, and about 10 to 30 mg / L of fluorine remains in the treated water. In order to further reduce the fluorine concentration in the treated water, a two-stage treatment method is also known in which fluorine is removed using a calcium compound and then fluorine is removed using an aluminum compound. In this case, the fluorine concentration of the treated water is usually 3 to 5
The limit is mg / L, and in order to remove fluorine more than that, it is necessary to significantly increase the amount of the aluminum compound, which is not practical. Removal of fluorine by fluorine adsorption resin has the problem that if the fluorine concentration of the water supplied to the resin is high, the adsorption capacity will be consumed in a short time and the frequency of regeneration will increase, and it is usually applied to fluorine-containing water with a low fluorine concentration. I do. As described above, even in the two-step treatment method of precipitation with a calcium compound and the precipitation with an aluminum compound, there is a limit to the fluorine concentration of the treated water. Has been
The quality of treated water is not necessarily improved. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for treating fluorine-containing water, which can efficiently remove fluorine to an extremely low concentration by treating the fluorine-containing water. It was done as. [0004] The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, arranged a fluorine-adsorbing resin after a two-stage treatment method using a calcium compound and an aluminum compound. Even so, the reason that the fluorine concentration in the treated water cannot be sufficiently reduced is that fluorine and aluminum form a complex, and this complex is not adsorbed by the fluorine adsorption resin. And the treated water is brought into contact with a fluorine adsorbent to reduce the fluorine concentration of the final treated water to 1
They have found that they can be reduced to mg / L or less, and have completed the present invention based on this finding. That is, the present invention provides a first step in which a calcium compound is added to fluorine-containing water and solid-liquid separation is performed, a second step in which an iron salt is added to treated water and solid-liquid separation is performed, and a second step treatment is performed. And a third step of bringing the water into contact with the fluorine adsorbent. In the method of the present invention, a calcium compound is added to fluorine-containing water to perform a solid-liquid separation, and an iron salt is added to treated water in the first step to perform solid-liquid separation. It comprises a second step and a third step of bringing the treated water into contact with the fluorine adsorbent. There is no particular limitation on the fluorine concentration of the fluorine-containing water to which the method of the present invention is applied.
By treating 30,000 mg / L fluorine-containing water, treated water having a fluorine concentration of 1 mg / L or less can be obtained. In the method of the present invention, in the first step, a calcium compound is added to water containing fluorine. The calcium compound to be added is not particularly limited, and examples thereof include calcium hydroxide, calcium oxide, calcium chloride, and calcium nitrate. The amount of the calcium compound to be added is not particularly limited, but is preferably 0.5 to 3 mol, more preferably 1 to 2.5 mol, as calcium ion per mol of fluorine ion in the fluorine-containing water. .
When the addition amount of the calcium compound is less than 0.5 mol as calcium ion per 1 mol of fluorine ion,
There is a possibility that calcium ions for forming calcium fluoride (CaF 2 ) are insufficient and the fluorine concentration in the treated water does not sufficiently decrease. The amount of calcium compound added is
3 moles of calcium ion per mole of fluorine ion
If the molar ratio is exceeded, the effect of lowering the fluorine ion concentration in water from the solubility product becomes relatively small, and the use amount of the calcium compound may unnecessarily increase. In the method of the present invention, after the calcium compound is added to the fluorine-containing water, the pH of the fluorine-containing water is adjusted to 6 to
It is preferably adjusted to 11, and more preferably adjusted to 6.5 to 10. If the pH is less than 6 or more than 11, the fluorine removal rate may decrease. The method for adding the calcium compound and the method for adjusting the pH are not particularly limited. For example, fluorine-containing water can be introduced into a mixing tank, and the calcium compound and the pH adjuster can be added and mixed.
When the fluorine concentration of the fluorine-containing water is high, and calcium hydroxide is used as the calcium compound, the surface of the calcium hydroxide particles is covered with calcium fluoride and the reaction rate is reduced, so it is preferable to provide sufficient stirring. . The residence time in the mixing tank is preferably 1 minute to 5 hours, more preferably 5 minutes to 1 hour. In the method of the present invention, a calcium compound is added, the pH is adjusted, and the fluorine-containing water in which calcium fluoride is precipitated,
It is preferable that the precipitate is transferred to a coagulation tank and a coagulant is added to coagulate the precipitate of calcium fluoride. There is no particular limitation on the flocculant to be added, polyacrylamide partial hydrolyzate,
A polymer flocculant such as a copolymer of acrylamide and sodium acrylate can be suitably used. The amount of the coagulant added is not particularly limited, but is preferably 0.01 to 10 mg / L, and more preferably 0.1 to 5 mg / L. The residence time in the flocculation tank is preferably from 1 minute to 5 hours, more preferably from 5 minutes to 1 hour. In the method of the present invention, the solid-liquid separation method in the first step is not particularly limited, and examples thereof include a precipitation method such as gravity precipitation and centrifugal precipitation, a membrane separation method using a microfiltration membrane, an ultrafiltration membrane, a reverse osmosis membrane, and the like. Can be mentioned. According to the method of the present invention, treated water in the first step having a fluorine concentration of 8 to 30 mg can be obtained. In the method of the present invention, in the second step, an iron salt is added to the treated water in the first step. It is preferable that the treated water in the first step is transferred to a coagulation tank to add an iron salt.
There is no particular limitation on the iron salt to be added, for example, ferrous chloride,
Examples include ferrous salts such as ferrous sulfate, ferric salts such as ferric chloride and ferric sulfate, and polyferrous salts such as polyiron hydrochloride and polyiron sulfate. The amount of the iron salt to be added is not particularly limited, but is preferably at least 3 times by weight, more preferably at least 5 times by weight, the fluorine ions present as iron in the first-step treated water. If the amount of the iron salt added is less than 3 times the weight of fluorine ions as iron, the removal of fluorine may be insufficient. The pH of the water to be treated in the second step is not particularly limited, and usually does not require pH adjustment, but is preferably around neutral. When an iron salt is added to the treated water in the first step, iron hydroxide flocs are generated and fluorine is precipitated by a coprecipitation phenomenon, so that the iron hydroxide flocs containing fluorine are separated into solid and liquid. There is no particular limitation on the solid-liquid separation method in the second step, and examples thereof include sedimentation methods such as gravity sedimentation, centrifugal sedimentation, anthracite, filtration methods using sand, microfiltration membranes, ultrafiltration membranes, reverse osmosis membranes, and the like. The membrane separation method to be used can be exemplified. One of these solid-liquid separation methods can be used alone, or two or more can be used in combination. According to the method of the present invention, treated water in the second step having a fluorine concentration of 3 to 8 mg / L can be obtained. In the method of the present invention, in the third step, the water treated in the second step is brought into contact with a fluorine adsorbent. Second
When only the precipitation method is used for the solid-liquid separation in the process, remove fine suspended substances contained in the treated water in the second step using a filter or the like to prevent clogging of the fluorine adsorbent due to the suspended substances. Is preferred. Examples of the fluorine adsorbent to be brought into contact with the treatment water in the second step include, for example, fluorinated resin adsorbing metal ions such as cerium, hafnium, titanium, zirconium, iron, aluminum and lanthanide, activated carbon,
Adsorbents such as activated alumina, hydrous titanium oxide, zeolite and magnesia can be mentioned. It is preferable to adjust the pH of the treated water to be brought into contact with the fluorine adsorbent to a suitable pH according to the characteristics of the fluorine adsorbent to be brought into contact. For example, when a commercially available fluorine-adsorbing resin [Asahi Engineering Co., Ltd., Lead F] is used, the pH is preferably adjusted to 3 to 5. There is no particular limitation on the method of bringing the treated water in the second step into contact with the fluorine adsorbent. For example, the treated water in the second step can be passed through a fluorine adsorption resin tower filled with a fluorine adsorption resin. There is no particular limitation on the water flow speed,
V1 to 50 h -1 , and SV 10 to 30
h- 1 is more preferred. The fluorine adsorption resin tower is
If necessary, it is preferable to stop the adsorption treatment and pass the regenerant to carry out the regeneration treatment. The regenerating agent can be appropriately selected depending on the characteristics of the fluorine-adsorbing resin.
An aqueous solution of sodium hydroxide, potassium hydroxide, sodium carbonate and the like, and hydrochloric acid and the like can be mentioned. According to the method of the present invention, the fluorine concentration of the treated water that has passed through the third step is
It becomes 1 mg / L or less. FIG. 1 is a flow chart of an embodiment of the method of the present invention. Fluorine-containing water is introduced into the mixing tank 1, a calcium compound and a pH adjuster are added, and the mixture is stirred and mixed, whereby most of the fluorine contained in the water is precipitated as calcium fluoride. The fluorine-containing water in which calcium fluoride is precipitated is sent to the flocculation tank 2 and a flocculant is added to convert the calcium fluoride precipitate into flocculated floc. The precipitate of the calcium fluoride which has become the flocculated floc is settled and separated in the sedimentation tank 3 to obtain treated water in the first step as supernatant water. By transferring the treated water in the first step to the coagulation tank 4 and adding an iron salt,
A floc of iron hydroxide is generated, and the remaining fluorine is precipitated by a coprecipitation phenomenon. The floc of iron hydroxide in which fluorine is coprecipitated is settled and separated in the sedimentation tank 5 to obtain treated water in the second step as supernatant water. The second-step treated water is passed through a filter 6 to remove mixed suspended substances, and then introduced into a pH adjusting tank 7 to which a pH adjusting agent is added. Adjust to a suitable pH. The water to be treated after the pH adjustment is passed through the fluorine adsorption resin tower 8 to obtain treated water having a fluorine concentration of 1 mg / L or less. According to the method for treating fluorine-containing water of the present invention, since a complex of fluorine and aluminum that is not easily adsorbed by the fluorine adsorbent is not generated, the treated water obtained by the two-stage treatment method using a calcium compound and an iron salt is used as the fluorine adsorbent. And the final treated water having a sufficiently low fluorine concentration can be easily obtained. The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the present invention. Example 1 700 mg / L of calcium hydroxide was added to wastewater of pH 4 containing 95 mg / L of fluorine, adjusted to pH 7.5 with sulfuric acid, and reacted with stirring for 20 minutes. Next, 1 mg / L of a polyacrylamide partial hydrolyzate was added, followed by precipitation and separation. The fluorine concentration of the supernatant water was 15 mg / L. To the supernatant water, 1,000 mg / L of ferric chloride was added, and the mixture was reacted with stirring for 20 minutes, and separated by precipitation. The fluorine concentration of the obtained supernatant water was 3 mg / L. After the supernatant water was subjected to sand filtration, the pH was adjusted to 4 with sulfuric acid, and water was passed through a fluorine adsorption resin tower filled with a fluorine adsorption resin [Asahi Engineering Co., Ltd., Lead F] at an SV of 25 h -1 . The fluorine concentration of the treated water flowing out of the fluorine adsorption resin tower was 1.0 mg / L. Comparative Example 1 Fluorine-containing water was treated in the same manner as in Example 1 except that polyaluminum chloride was added instead of ferric chloride. The fluorine concentration of the supernatant water obtained by adding polyaluminum chloride was 8 mg / L. The fluorine concentration of the treated water flowing out of the fluorine adsorption resin tower is 3.5 mg /
L. Table 1 shows the results of Example 1 and Comparative Example 1. [Table 1] According to the method for treating fluorine-containing water of the present invention, since a complex of fluorine and aluminum which is not easily adsorbed by the fluorine adsorbent is not formed, a two-stage treatment method using a calcium compound and an iron salt is performed. The obtained treated water is brought into contact with the fluorine adsorbent, so that final treated water having a sufficiently low fluorine concentration can be easily obtained.
【図面の簡単な説明】
【図１】図１は、本発明方法の実施の一態様の工程系統
図である。
【符号の説明】
１ 混合槽
２ 凝集槽
３ 沈殿槽
４ 凝集槽
５ 沈殿槽
６ ろ過器
７ pH調整槽
８ フッ素吸着樹脂塔BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process flow chart of one embodiment of the method of the present invention. [Description of Signs] 1 Mixing tank 2 Coagulation tank 3 Precipitation tank 4 Coagulation tank 5 Precipitation tank 6 Filter 7 pH adjustment tank 8 Fluorine adsorption resin tower
Claims (1)
し、固液分離する第１工程と、第１工程処理水に鉄塩を
添加し、固液分離する第２工程と、第２工程処理水をフ
ッ素吸着体と接触させる第３工程とからなることを特徴
とするフッ素含有水の処理方法。Claims: 1. A first step in which a calcium compound is added to fluorine-containing water and solid-liquid separation is performed, and a second step in which an iron salt is added to treated water and solid-liquid separation is performed. And a third step of contacting the treated water with the fluorine adsorbent in the second step.
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| JP2002067222A JP4103031B2 (en) | 2002-03-12 | 2002-03-12 | Fluorine-containing water treatment method |
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| JP2003260472A true JP2003260472A (en) | 2003-09-16 |
| JP4103031B2 JP4103031B2 (en) | 2008-06-18 |
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Cited By (8)
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| JP2006000026A (en) * | 2004-06-16 | 2006-01-05 | Audio Technica Corp | Cooked rice forming device |
| JP2006051432A (en) * | 2004-08-11 | 2006-02-23 | Dowa Mining Co Ltd | Treatment method of f-containing solution |
| JP2007177278A (en) * | 2005-12-27 | 2007-07-12 | Mitsui Mining & Smelting Co Ltd | Fluorine-adsorbing-desorbing agent for use in removing fluorine from process liquid for wet zinc-smelting process, and method for removing fluorine with the use of the fluorine-adsorbing-desorbing agent |
| JP2008237947A (en) * | 2007-03-23 | 2008-10-09 | Nippon Rensui Co Ltd | Ion-containing wastewater treatment apparatus and method |
| JP2009202147A (en) * | 2008-01-31 | 2009-09-10 | Japan Organo Co Ltd | Crystallization reactor system and crystallization reaction method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006000026A (en) * | 2004-06-16 | 2006-01-05 | Audio Technica Corp | Cooked rice forming device |
| JP2006051432A (en) * | 2004-08-11 | 2006-02-23 | Dowa Mining Co Ltd | Treatment method of f-containing solution |
| JP2007177278A (en) * | 2005-12-27 | 2007-07-12 | Mitsui Mining & Smelting Co Ltd | Fluorine-adsorbing-desorbing agent for use in removing fluorine from process liquid for wet zinc-smelting process, and method for removing fluorine with the use of the fluorine-adsorbing-desorbing agent |
| JP2008237947A (en) * | 2007-03-23 | 2008-10-09 | Nippon Rensui Co Ltd | Ion-containing wastewater treatment apparatus and method |
| JP2009202147A (en) * | 2008-01-31 | 2009-09-10 | Japan Organo Co Ltd | Crystallization reactor system and crystallization reaction method |
| JP2012210629A (en) * | 2008-01-31 | 2012-11-01 | Japan Organo Co Ltd | Crystallization reactor apparatus and crystallization reaction method |
| JP2012157834A (en) * | 2011-02-01 | 2012-08-23 | Yoshizawa Lime Industry | Removing agent for harmful substances in wastewater and removal method using the same |
| CN103253788A (en) * | 2012-12-28 | 2013-08-21 | 中国科学院生态环境研究中心 | Method for removing fluorides in water through aluminum base composite metal oxide-based fluorine removing absorption material complexation-absorption |
| CN103253788B (en) * | 2012-12-28 | 2014-07-09 | 中国科学院生态环境研究中心 | Method for removing fluorides in water through aluminum base composite metal oxide-based fluorine removing absorption material complexation-absorption |
| CN114100585A (en) * | 2020-08-26 | 2022-03-01 | 兰州石化职业技术学院 | Defluorinating agent for drinking water |
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