JPH09176874A - Method for regenerating and recovering acid liquid mixture such as waste nitric acid-hydrofluoric acid mixture - Google Patents
Method for regenerating and recovering acid liquid mixture such as waste nitric acid-hydrofluoric acid mixtureInfo
- Publication number
- JPH09176874A JPH09176874A JP33356395A JP33356395A JPH09176874A JP H09176874 A JPH09176874 A JP H09176874A JP 33356395 A JP33356395 A JP 33356395A JP 33356395 A JP33356395 A JP 33356395A JP H09176874 A JPH09176874 A JP H09176874A
- Authority
- JP
- Japan
- Prior art keywords
- acid
- hydrofluoric acid
- nitric
- alkali
- recovered
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/36—Regeneration of waste pickling liquors
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は硝フッ酸廃液等の酸
混合液の再生回収処理方法、さらに詳しくは、金属の酸
洗工程等において排出される硝フッ酸等の混合酸を含有
する廃液中から、金属スラッジを除去して硝フッ酸等の
混合酸を再生回収する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating and recovering an acid mixed solution such as nitric hydrofluoric acid waste solution, and more specifically, a waste solution containing a mixed acid such as nitric hydrofluoric acid discharged in a metal pickling process. The present invention relates to a method of regenerating and recovering mixed acid such as nitric hydrofluoric acid by removing metal sludge from the inside.
【０００２】[0002]
【従来の技術】従来、この種の硝フッ酸等の混合酸を含
有する廃液から混合酸を再生回収処理する方法であって
本発明に近似する先行技術として特公表62−502695号に
開示された発明がある。2. Description of the Related Art Conventionally, a method for regenerating and recovering a mixed acid from a waste liquid containing a mixed acid such as nitric hydrofluoric acid, which is a prior art similar to the present invention, is disclosed in Japanese Patent Publication No. 62-502695. There is an invention.
【０００３】すなわちこの発明は、図３に示すように先
ず原水槽1aの硝フッ酸廃液等の酸混合液をｐＨ調整槽2a
に供給し、アルカリ（たとえばＫＯＨ）を添加し、中和
して金属等を沈澱分離し、その濾液をバイポーラ膜、陽
イオン交換膜、陰イオン交換膜を備えたバイポーラ膜装
置4aを通過させて混合酸とアルカリとに分離して再生回
収する方法である。That is, according to the present invention, as shown in FIG. 3, first, an acid mixed solution such as a nitric hydrofluoric acid waste solution in a raw water tank 1a is adjusted to a pH adjusting tank 2a.
And then add an alkali (for example, KOH) to neutralize and precipitate and separate metals and the like, and pass the filtrate through a bipolar membrane device 4a equipped with a bipolar membrane, a cation exchange membrane, and an anion exchange membrane. In this method, the mixed acid and alkali are separated and regenerated and recovered.
【０００４】そして混合酸は酸洗槽11a に供給されて再
利用され、アルカリは再度ｐＨ調整槽2aに返送されて中
和用として再利用される。The mixed acid is supplied to the pickling tank 11a for reuse, and the alkali is returned to the pH adjusting tank 2a again for reuse for neutralization.
【０００５】[0005]
【発明が解決しようとする課題】ところが、このような
従来の方法では、回収される混合酸のうち、硝酸に比べ
るとフッ酸は回収され難く、回収フッ酸の濃度が低くな
る傾向がある。However, in such a conventional method, hydrofluoric acid is less likely to be recovered than nitric acid in the recovered mixed acid, and the concentration of recovered hydrofluoric acid tends to be low.
【０００６】この従来の方法はいわゆるクローズドシス
テムで行われ、回収された混合酸は繰り返して使用され
るため、いわゆるバッチ運転の場合、バッチ回数を重ね
ることによりフッ酸の濃度が高まり、所望の濃度のフッ
酸は得られる。This conventional method is performed in a so-called closed system, and the recovered mixed acid is repeatedly used. Therefore, in so-called batch operation, the concentration of hydrofluoric acid is increased by increasing the number of batches, and the desired concentration is obtained. Hydrofluoric acid is obtained.
【０００７】しかし、装置の立ち上げ時には目的に応じ
た所望濃度のフッ酸は回収されず、従来では複数回のバ
ッチ回数を経なければ所望濃度のフッ酸を回収できない
のが現状であった。従って、回収された混合酸を酸洗槽
に供給して再利用するためには、別途フッ酸を追加して
未回収分のフッ酸に相当する量を補充する必要があっ
た。However, the hydrofluoric acid having a desired concentration according to the purpose is not recovered when the apparatus is started up, and conventionally, it has been impossible to recover the hydrofluoric acid having a desired concentration until a plurality of batches have been performed. Therefore, in order to supply the recovered mixed acid to the pickling tank for reuse, it was necessary to add hydrofluoric acid separately to replenish the amount corresponding to the unrecovered hydrofluoric acid.
【０００８】ちなみに、廃酸中のフッ酸の濃度がたとえ
ば1.5 eq/L（１リットルあたりのグラム当量）の場合、
回収されるフッ酸の濃度は、図４に示すように１バッチ
目では約0.9 eq/Lであり、２バッチ目では約1.0 eq/Lと
なり、３バッチ目では約1.3eq/Lとなり、４バッチ目で
約1.5 eq/Lとなる。Incidentally, when the concentration of hydrofluoric acid in the waste acid is, for example, 1.5 eq / L (gram equivalent per liter),
As shown in Fig. 4, the concentration of recovered hydrofluoric acid was about 0.9 eq / L for the first batch, about 1.0 eq / L for the second batch, and about 1.3 eq / L for the third batch. It becomes about 1.5 eq / L in the batch.
【０００９】すなわち、従来では、廃酸中のフッ酸と同
等の濃度の回収フッ酸を得るために４バッチを要するこ
ととなり、かつ所望濃度のフッ酸を得るために不足する
フッ酸を別途投入するという不都合を生じていたのであ
る。That is, conventionally, four batches are required to obtain recovered hydrofluoric acid at a concentration equivalent to that of hydrofluoric acid in waste acid, and hydrofluoric acid which is insufficient to obtain a desired concentration of hydrofluoric acid is added separately. It caused the inconvenience of doing.
【００１０】本発明は、このような問題点を解決するた
めになされたもので、数回のバッチ回数を経なくとも所
望濃度のフッ酸を回収することができ、ひいては装置の
立ち上げ運転の時間を大幅に短縮することを課題とする
ものである。The present invention has been made in order to solve such a problem, and it is possible to recover hydrofluoric acid of a desired concentration without passing through several batches, and thus to start up the apparatus. The challenge is to significantly reduce the time.
【００１１】[0011]
【課題を解決するための手段】本発明は、このような課
題を解決するためになされたもので、その課題を解決す
るための手段は、硝フッ酸廃液等の酸混合液を、アルカ
リで中和し金属等を沈澱分離した後、濾液をバイポーラ
膜５、陽イオン交換膜６、陰イオン交換膜７を備えたバ
イポーラ膜装置４に供給して該バイポーラ膜装置４から
酸とアルカリとを分離し再生回収する硝フッ酸廃液等の
酸混合液の再生回収処理方法において、前記アルカリで
の中和工程で生ずる中性塩であって、回収される混合酸
を構成するアニオン成分のうち、混合酸中の全アニオン
成分に対して存在する比率が、濾液中の全アニオン成分
に対して存在する比率より低くなるアニオン成分を含む
中性塩を、前記バイポーラ膜装置４への供給前に予め添
加することにある。Means for Solving the Problems The present invention has been made to solve such problems, and means for solving the problems is to use an acid mixed solution such as nitric-hydrofluoric acid waste solution with an alkali. After neutralizing and separating the metal and the like by precipitation, the filtrate is supplied to a bipolar membrane device 4 equipped with a bipolar membrane 5, a cation exchange membrane 6 and an anion exchange membrane 7, and the acid and alkali are extracted from the bipolar membrane device 4. In the method for regenerating and recovering an acid mixed solution such as a nitric hydrofluoric acid waste solution that is separated and regenerated and recovered, a neutral salt generated in the neutralization step with the alkali, of the anion components that form the mixed acid to be recovered, Before supplying to the bipolar membrane device 4, a neutral salt containing an anion component whose ratio relative to all anion components in the mixed acid is lower than that relative to all anion components in the filtrate is previously prepared. To add
【００１２】この中性塩は、バイポーラ膜装置６への供
給前に添加されればよいが、アルカリでの中和工程後に
添加されるのが好ましい。The neutral salt may be added before being supplied to the bipolar membrane device 6, but is preferably added after the step of neutralizing with an alkali.
【００１３】また、中性塩の性状としては、濾液の濃度
を高める観点から固体のもの、より具体的には粉末状の
ものを使用することが好ましい。As the property of the neutral salt, it is preferable to use a solid salt, more specifically a powdery one, from the viewpoint of increasing the concentration of the filtrate.
【００１４】さらに、中性塩としては、酸混合液が硝フ
ッ酸廃液である場合には、フッ化カリウムが使用され
る。Further, as the neutral salt, potassium fluoride is used when the acid mixture is a nitric hydrofluoric acid waste liquid.
【００１５】上述のように、回収される混合酸を構成す
るアニオン成分のうち、混合酸中の全アニオン成分に対
して存在する比率が、濾液中の全アニオン成分に対して
存在する比率より低くなるアニオン成分を含む中性塩
を、予めバイポーラ膜装置４への供給前に添加しておく
と、その中性塩に起因して回収される酸の濃度が高まる
こととなる。As described above, the ratio of the anion components constituting the recovered mixed acid to the total anion components in the mixed acid is lower than the ratio to the total anion components in the filtrate. If a neutral salt containing the following anion component is added in advance before being supplied to the bipolar membrane device 4, the concentration of the acid recovered due to the neutral salt will increase.
【００１６】従って、酸混合液が硝フッ酸廃液である場
合には、フッ化カリウムのような金属フッ素化物の中性
塩をバイポーラ膜装置４への供給前に添加することで、
装置の立ち上げ運転時より所望濃度のフッ酸が回収され
ることとなるのである。Therefore, when the acid mixed solution is a nitric hydrofluoric acid waste solution, by adding a neutral salt of a metal fluoride such as potassium fluoride before supplying it to the bipolar membrane device 4,
The desired concentration of hydrofluoric acid will be recovered from the start-up operation of the apparatus.
【００１７】[0017]
【発明の実施の形態】以下、本発明の実施形態について
説明する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
【００１８】実施形態１ 本実施例は、酸混合液の一例としての硝フッ酸廃液から
の硝フッ酸の再生回収方法の実施例である。 Embodiment 1 This example is an example of a method for regenerating and recovering nitric hydrofluoric acid from a nitric hydrofluoric acid waste liquid as an example of an acid mixed liquid.
【００１９】先ず、この再生回収方法に使用する装置の
構成について説明する。First, the structure of the apparatus used in this recycling method will be described.
【００２０】図１において、１は原液としての硝フッ酸
廃液を貯留するための原液貯留槽、２は前記硝フッ酸廃
液中の硝フッ酸を中和するためのｐＨ調整槽で、流路３
を介して前記原液貯留槽１に接続されている。In FIG. 1, 1 is a stock solution storage tank for storing a nitric hydrofluoric acid waste solution as a stock solution, 2 is a pH adjusting tank for neutralizing the nitric hydrofluoric acid in the nitric hydrofluoric acid waste solution, and a flow path Three
It is connected to the stock solution storage tank 1 via.
【００２１】４は、前記ｐＨ調整槽２で中和されて金属
等が沈澱分離された濾液を、酸、アルカリ、及び脱塩水
に分離するためのバイポーラ膜装置で、バイポーラ膜
５、陽イオン交換膜６、陰イオン交換膜７を備えた構成
からなり、流路12を介して前記ｐＨ調整槽２に接続され
ている。Numeral 4 is a bipolar membrane device for separating the filtrate, which is neutralized in the pH adjusting tank 2 and precipitated and separated from metals and the like, into acid, alkali, and demineralized water. It is composed of a membrane 6 and an anion exchange membrane 7, and is connected to the pH adjusting tank 2 via a channel 12.
【００２２】そして、そのバイポーラ膜装置４の酸ライ
ン８は、金属等を洗浄する酸洗槽11に接続されており、
またアルカリライン９は前記ｐＨ調整槽２に接続されて
おり、さらに中性塩ライン10はそのまま脱塩水が排出さ
れるように設けられている。The acid line 8 of the bipolar membrane device 4 is connected to a pickling tank 11 for washing metal or the like,
The alkali line 9 is connected to the pH adjusting tank 2, and the neutral salt line 10 is provided so that the desalted water is discharged as it is.
【００２３】次に、上記のような構成からなる再生回収
装置で、硝フッ酸廃液から硝フッ酸を再生回収する方法
について説明する。Next, a method of regenerating and recovering nitric hydrofluoric acid from the nitric hydrofluoric acid waste liquid by the reclaiming apparatus having the above-mentioned structure will be described.
【００２４】先ず、ステンレス鋼材等を洗浄した後の硝
フッ酸廃液を、原液貯留槽１から流路３を経てｐＨ調整
槽２へ供給する。First, the nitric hydrofluoric acid waste liquid after cleaning the stainless steel material and the like is supplied from the stock solution storage tank 1 through the flow path 3 to the pH adjusting tank 2.
【００２５】ｐＨ調整槽２に供給された硝フッ酸廃液に
は、水酸化カリウム（ＫＯＨ）が添加されて中和され
る。Potassium hydroxide (KOH) is added to the nitric hydrofluoric acid waste liquid supplied to the pH adjusting tank 2 for neutralization.
【００２６】このとき、金属スラッジとして水酸化鉄，
水酸化クロム，水酸化ニッケル等の水酸化金属が沈澱
し、その濾液（ＫＦとＫＮＯ3)が流路12を経てバイポー
ラ膜装置４に供給される。At this time, iron hydroxide as metal sludge,
Metal hydroxide such as chromium hydroxide or nickel hydroxide is precipitated, and the filtrate (KF and KNO 3 ) is supplied to the bipolar membrane device 4 through the flow path 12.
【００２７】ここで、ｐＨ調整槽２からバイポーラ膜装
置４へ供給される前の濾液（ＫＦとＫＮＯ3)に、中性塩
としてフッ化カリウム（ＫＦ）の粉末が濾液に溶解する
ように添加される。このように粉末で添加する場合に
は、取扱いが容易であり、溶液と異なり水分を余分に加
えることがなく、また濾液の濃度が下がらない等の利点
がある。Here, potassium fluoride (KF) powder as a neutral salt is added to the filtrate (KF and KNO 3 ) before being supplied from the pH adjusting tank 2 to the bipolar membrane device 4 so as to be dissolved in the filtrate. To be done. Thus, the addition in the form of powder has advantages that it is easy to handle, no extra water is added unlike the solution, and the concentration of the filtrate does not decrease.
【００２８】供給された濾液（ＫＦとＫＮＯ3)は、バイ
ポーラ膜装置４内で電離して該バイポーラ膜装置４の酸
ライン８からフッ酸（ＨＦ）及び硝酸（ＨＮＯ3)が分離
され、アルカリライン９からは水酸化カリウム（ＫＯ
Ｈ）が分離される。The supplied filtrate (KF and KNO 3 ) is ionized in the bipolar membrane device 4 to separate hydrofluoric acid (HF) and nitric acid (HNO 3 ) from the acid line 8 of the bipolar membrane device 4, and the alkali From line 9 potassium hydroxide (KO
H) is separated.
【００２９】これをより詳細に説明すると、前記濾液は
前記バイポーラ膜装置４の脱塩室13を通過するが、この
とき脱塩室13中のＫＦは、図２に示すようにＫ+イオン
とＦ-イオンとに電離しており、またＫＮＯ3はＫ+イオ
ンとＮＯ3 -イオンとに電離している。Explaining this in more detail, the filtrate passes through the desalting chamber 13 of the bipolar membrane device 4, and at this time, KF in the desalting chamber 13 becomes K + ions as shown in FIG. F − ions are ionized, and KNO 3 is ionized into K + ions and NO 3 − ions.
【００３０】そして、陽イオンであるＫ+は陽イオン交
換膜６を介してアルカリライン９側へ移動し、陰イオン
であるＦ-やＮＯ3 -は陰イオン交換膜７を介して酸ライ
ン８側へ移動する。The cation K + moves to the alkali line 9 side through the cation exchange membrane 6, and the anions F − and NO 3 − pass through the anion exchange membrane 7 and the acid line 8 side. Move to the side.
【００３１】一方、バイポーラ膜５に接液するアルカリ
ライン９と酸ライン８に存在する水の一部がバイポーラ
膜５内部に浸透し、Ｈ+とＯＨ-とに電離し、Ｈ+は陰極
側に移動し、ＯＨ-は陽極側に移動する。On the other hand, part of the water existing in the alkaline line 9 and the acid line 8 which come into contact with the bipolar film 5 penetrates into the bipolar film 5 and is ionized into H + and OH −, and H + is on the cathode side. , And OH − moves to the anode side.
【００３２】従って、バイポーラ膜５内で電離したＨ+
は、バイポーラ膜５の陽イオン交換側を介して酸ライン
８側へ移動し、その酸ライン８において上記のようにし
て得られたＦ-やＮＯ3 -と結合してＨＦやＨＮＯ3が生成
され、そのＨＦやＨＮＯ3が酸ライン８から分離回収さ
れることとなる。Therefore, H + ionized in the bipolar film 5 is
Moves to the acid line 8 side through the cation exchange side of the bipolar membrane 5 and combines with the F − and NO 3 − obtained as described above in the acid line 8 to produce HF and HNO 3. The HF and HNO 3 are separated and recovered from the acid line 8.
【００３３】また、バイポーラ膜５内で電離したＯＨ-
は、バイポーラ膜５の陰イオン交換側を介してアルカリ
ライン９側へ移動し、そのアルカリライン９において上
記のようにして得られたＫ+と結合してＫＯＨが生成さ
れ、そのＫＯＨがアルカリライン９から分離回収される
こととなる。OH − ionized in the bipolar film 5
Moves to the alkali line 9 side through the anion exchange side of the bipolar membrane 5 and is combined with the K + obtained as described above in the alkali line 9 to generate KOH. 9 will be separated and collected.
【００３４】一方、脱塩室13では、濾液中に含有されて
いるＫＦやＫＮＯ3が脱塩された状態で通過する。On the other hand, in the desalting chamber 13, KF and KNO 3 contained in the filtrate pass in a desalted state.
【００３５】脱塩室13において、Ｋ+及びＦ-はそれぞれ
アルカリライン９，酸ライン８に移動をし、ＫＦが消費
されることにより濃度が低くなり、消費されなかったＫ
Ｆはそのまま脱塩室13を通過することとなる。In the desalting chamber 13, K + and F − move to the alkali line 9 and the acid line 8, respectively, and the KF is consumed, so that the concentration is lowered and the K is not consumed.
F will pass through the desalting chamber 13 as it is.
【００３６】そして、酸ライン８から分離されたフッ酸
（ＨＦ）や硝酸（ＨＮＯ3)は、酸洗槽11に返送され、さ
らに原液貯留槽１へ返送される。The hydrofluoric acid (HF) and nitric acid (HNO 3 ) separated from the acid line 8 are returned to the pickling tank 11 and further to the stock solution storage tank 1.
【００３７】また、アルカリライン９から分離された水
酸化カリウム（ＫＯＨ）はｐＨ調整槽２へ返送されて中
和用のアルカリとして再利用される。The potassium hydroxide (KOH) separated from the alkali line 9 is returned to the pH adjusting tank 2 and reused as an alkali for neutralization.
【００３８】このように酸とアルカリとが分離回収され
る過程において、酸のうち硝酸はフッ酸に比べて回収さ
れ易い。In the process of separating and recovering the acid and the alkali in this way, nitric acid in the acid is more easily recovered than hydrofluoric acid.
【００３９】これは、バイポーラ膜装置４においてＮＯ
3 -の方がＦ-よりも陽イオン交換膜６を通過し易いため
と推定される。This means that in the bipolar membrane device 4 NO
It is presumed that 3 − is easier to pass through the cation exchange membrane 6 than F − .
【００４０】すなわち、ＫＮＯ3の解離度に比べＫＦの
解離度の方が低いため、ＫＦは膜を透過しにくく、ＫＦ
の一部はＫＦのまま中性塩ライン10に残る。従って酸ラ
イン８から回収される混合酸中のＦ-成分の比率は濾液
中の比率よりも低くなる。That is, since the dissociation degree of KF is lower than that of KNO 3 , it is difficult for KF to permeate through the membrane and KF
Part of the salt remains in the neutral salt line 10 as KF. Therefore, the ratio of the F − component in the mixed acid recovered from the acid line 8 becomes lower than that in the filtrate.
【００４１】従って、濾液中のＫＦとＫＮＯ3のアニオ
ン成分Ｆ-とＮＯ3 -では回収率に差が生ずることとな
り、回収される混合酸中の全アニオン成分に対するＦ-
成分の比率は濾液中の全アニオン成分に対するＦ-成分
の比率より低下することとなる。[0041] Thus, the anion component of KF and KNO 3 in the filtrate F - and NO 3 - in the difference in the recovery rate will be occurs, F to all anionic components in the mixed acid to be recovered -
The ratio of the components will be lower than the ratio of the F − component to all the anionic components in the filtrate.
【００４２】このような理由により、一般には、酸の分
離回収の運転の初期においては、硝酸に比べるとフッ酸
の濃度は低くなるのである。For these reasons, the concentration of hydrofluoric acid is generally lower than that of nitric acid in the initial stage of the operation for separating and recovering acid.
【００４３】しかし、本実施形態では、バイポーラ膜装
置４へ処理水が供給される前にフッ化カリウム（ＫＦ）
が添加されるため、中和後に生じている中性塩のＫＦ及
びＫＮＯ3のうち、ＫＦの濃度が高くなる。However, in this embodiment, potassium fluoride (KF) is supplied before the treated water is supplied to the bipolar membrane device 4.
Since K is added, the concentration of KF in the neutral salts KF and KNO 3 generated after neutralization is high.
【００４４】すなわち、ＫＦをバイポーラ装置への供給
前の濾液に添加することにより、中性塩ライン10中には
中和槽２からの中性塩に含まれるＫＦと合わせてＫＦの
物質量が増加する。That is, by adding KF to the filtrate before the supply to the bipolar device, the amount of KF contained in the neutral salt line 10 together with KF contained in the neutral salt from the neutralization tank 2 is increased. To increase.
【００４５】従って、ＫＦの解離度が低くても、ＫＦの
量が増加しているため、解離するアニオン成分（Ｆ-）
の量が増加する。そして、膜を通過するアニオン成分
（Ｆ-）が増加し、酸ライン８において、フッ酸（Ｈ
Ｆ）となり、その結果、回収される混合酸中のフッ酸の
濃度が高くなる。Therefore, even if the degree of dissociation of KF is low, the amount of KF increases, so that the anion component (F − ) that dissociates is released.
Increase the amount of. Then, the anion component (F − ) passing through the membrane increases, and in the acid line 8, hydrofluoric acid (H −
F), and as a result, the concentration of hydrofluoric acid in the recovered mixed acid increases.
【００４６】この結果、バイポーラ膜装置４の通過後に
フッ酸の方が硝酸に比べて回収し難いとしても、予めフ
ッ化カリウムが添加されているために、回収されるフッ
酸の濃度が硝酸の濃度に比べて極端に低下することもな
く、適度に濃度調整がされることとなるのである。As a result, even though hydrofluoric acid is more difficult to collect after passing through the bipolar membrane device 4 than nitric acid, the concentration of the recovered hydrofluoric acid is nitric acid because potassium fluoride is added in advance. The density will not be extremely lowered compared to the density, and the density will be adjusted appropriately.
【００４７】その他の実施形態 尚、上記実施例では、酸混合液として硝フッ酸廃液を用
いる場合について説明したが、廃液中に含有される酸の
種類はこれに限定されるものではなく、これ以外の酸混
合液、たとえば硫酸とフッ酸の酸混合液、塩酸と硫酸の
酸混合液等に本発明を適用することも可能である。 Other Embodiments In the above examples, the case where the nitric hydrofluoric acid waste liquid is used as the acid mixed liquid has been described, but the kind of the acid contained in the waste liquid is not limited to this. It is also possible to apply the present invention to an acid mixed solution other than the above, such as an acid mixed solution of sulfuric acid and hydrofluoric acid and an acid mixed solution of hydrochloric acid and sulfuric acid.
【００４８】ちなみに、硫酸とフッ酸との酸混合液の場
合には、回収混合酸中のアニオン成分の比率が濾液中の
アニオン成分の比率よりも低くなるのはＦ-であり、従
ってこの場合にも添加する中性塩としてはＫＦ等が用い
られる。By the way, in the case of the acid mixture of sulfuric acid and hydrofluoric acid, it is F − that the ratio of the anion component in the recovered mixed acid is lower than the ratio of the anion component in the filtrate. KF or the like is used as the neutral salt to be added.
【００４９】また、塩酸と硫酸との酸混合液の場合に
は、回収混合酸中のアニオン成分の比率が濾液中のアニ
オン成分の比率よりも低くなるのはＳＯ4 -であり、この
場合には添加する中性塩としてはＮａ2ＳＯ4が用いられ
る。In the case of an acid mixture of hydrochloric acid and sulfuric acid, it is SO 4 − that the ratio of the anion component in the recovered mixed acid is lower than the ratio of the anion component in the filtrate. Na 2 SO 4 is used as the neutral salt to be added.
【００５０】また、廃液の種類も、ステンレス鋼材の洗
浄後の廃液の他、他の種類の廃液に本発明を適用するこ
とも可能である。As for the type of waste liquid, the present invention can be applied to other types of waste liquid, in addition to the waste liquid after cleaning the stainless steel material.
【００５１】さらに、本発明は、主として上記のような
廃液に適用することを主眼とするものではあるが、廃液
以外の酸混合液に本発明を適用することも可能である。Further, although the present invention is mainly intended to be applied to the above waste liquid, the present invention can also be applied to an acid mixed liquid other than the waste liquid.
【００５２】[0052]
【実施例】実施例１ 濃度２eq/Lのフッ酸（ＨＦ）と濃度２eq/Lの硝酸を含む
硝フッ酸廃液10m3に、濃度２eq/Lの苛性カリ（ＫＯＨ）
20m3を添加して中和し、金属スラッジを沈澱させた。 Example 1 10 m 3 of nitric hydrofluoric acid waste liquid containing hydrofluoric acid (HF) at a concentration of 2 eq / L and nitric acid at a concentration of 2 eq / L was added to caustic potash (KOH) at a concentration of 2 eq / L.
20 m 3 was added to neutralize and precipitate the metal sludge.
【００５３】中和後の濾液には濃度0.67eq/Lのフッ化カ
リウム（ＫＦ）と、濃度0.67eq/Lの硝酸カリウム（ＫＮ
Ｏ3)とが含まれており、この濾液30m3に7.6 keq(キログ
ラム当量）のフッ化カリウムの粉末を添加する。The neutralized filtrate contains potassium fluoride (KF) having a concentration of 0.67 eq / L and potassium nitrate (KN) having a concentration of 0.67 eq / L.
O 3 ) and 7.6 keq (kilogram equivalent) potassium fluoride powder is added to 30 m 3 of this filtrate.
【００５４】このフッ化カリウムの粉末の添加により、
濾液中の硝酸カリウム（ＫＮＯ3)の濃度が0.67eq/Lであ
るのに対し、フッ化カリウム（ＫＦ）の濃度は0.92eq/L
となる。By adding the powder of potassium fluoride,
The concentration of potassium nitrate (KNO 3 ) in the filtrate is 0.67 eq / L, while the concentration of potassium fluoride (KF) is 0.92 eq / L.
Becomes
【００５５】この濾液をバイポーラ膜装置を通過させる
と、容量10m3の酸が回収され、その回収酸中には濃度
２.0eq/Lのフッ酸（ＨＦ）と濃度２.0eq/Lの硝酸が含ま
れていた。よって、当初の硝フッ酸廃液中の濃度を同じ
フッ酸及び硝酸が１回目のバッチで回収することができ
た。When this filtrate was passed through a bipolar membrane device, an acid having a volume of 10 m 3 was recovered. The recovered acid contained hydrofluoric acid (HF) at a concentration of 2.0 eq / L and nitric acid at a concentration of 2.0 eq / L. Was included. Therefore, the same concentration of hydrofluoric acid and nitric acid in the initial nitric-hydrofluoric acid waste liquid could be recovered in the first batch.
【００５６】また、容量19m3の脱塩液が回収され、その
脱塩液中のフッ化カリウム（ＫＦ）の濃度は0.4eq/Lで
あった。A desalted solution having a volume of 19 m 3 was recovered, and the concentration of potassium fluoride (KF) in the desalted solution was 0.4 eq / L.
【００５７】比較例 比較例として、バイポーラ膜装置への供給前にフッ化カ
リウムを添加しない場合についての回収酸の濃度を測定
した。 Comparative Example As a comparative example, the concentration of the recovered acid was measured before adding potassium fluoride to the bipolar membrane device.
【００５８】実施例１と同様に、濃度２eq/Lのフッ酸
（ＨＦ）と濃度２eq/Lの硝酸（ＨＮＯ 3)を含む硝フッ酸
廃液10m3に、濃度２eq/Lの苛性カリ（ＫＯＨ）20m3を添
加して中和し、金属スラッジを沈澱させた。As in Example 1, hydrofluoric acid with a concentration of 2 eq / L
(HF) and nitric acid (HNO Three) Containing nitric hydrofluoric acid
Waste liquid 10mThree20m of caustic potash (KOH) with a concentration of 2eq / LThreeWith
It was neutralized by adding to precipitate metal sludge.
【００５９】中和後の濾液の濃度は、実施例１と同様に
フッ化カリウム（ＫＦ）が0.67eq/L、硝酸カリウム（Ｋ
ＮＯ3)が0.67eq/Lであるが、実施例１のようにフッ化カ
リウム粉末の添加を行わず、そのままバイポーラ膜装置
を通過させた。As in Example 1, the concentration of the filtrate after neutralization was 0.67 eq / L for potassium fluoride (KF) and potassium nitrate (KF).
Although NO 3 ) was 0.67 eq / L, potassium fluoride powder was not added as in Example 1 and the solution was allowed to pass through the bipolar membrane device as it was.
【００６０】回収された脱塩液の量と濃度は実施例１と
同様で19m3及び0.4eq/Lであったが、回収酸中の硝酸の
濃度は2.47eq/L、フッ酸の濃度は1.53eq/Lであった。The amount and concentration of the recovered desalted solution were 19 m 3 and 0.4 eq / L as in Example 1, but the concentration of nitric acid in the recovered acid was 2.47 eq / L, and the concentration of hydrofluoric acid was It was 1.53 eq / L.
【００６１】実施例１と比較すると硝酸の濃度が高く、
フッ酸の濃度が低かったが、これは実施例１のようにフ
ッ化カリウム粉末の添加を比較例で行わなかったためと
推定される。回収酸中のフッ酸の濃度は、硝フッ酸廃液
のフッ酸の濃度より低いので、酸洗槽で再利用するため
には、未回収のフッ酸に相当する量（本比較例では濃度
４eq/L、容量1.9m3）のフッ酸を新たに補充しなければ
ならない。As compared with Example 1, the concentration of nitric acid was high,
The concentration of hydrofluoric acid was low, which is presumed to be because the addition of the potassium fluoride powder was not performed in the comparative example as in Example 1. Since the concentration of hydrofluoric acid in the recovered acid is lower than the concentration of hydrofluoric acid in the nitric hydrofluoric acid waste liquid, in order to reuse the hydrofluoric acid in the pickling tank, an amount corresponding to unrecovered hydrofluoric acid (concentration 4 eq in this comparative example) was used. / L, capacity 1.9m 3 ) must be newly replenished with hydrofluoric acid.
【００６２】考察 以上のような実施例１と比較例との対比により、バイポ
ーラ膜装置への供給前にフッ化カリウム粉末を添加させ
ておくことにより、回収酸中の硝酸とフッ酸の濃度調整
を好適に行うことが可能となり、特にフッ酸の濃度低下
を防止することができた。 Consideration From the comparison between Example 1 and Comparative Example as described above, the concentration of nitric acid and hydrofluoric acid in the recovered acid was adjusted by adding potassium fluoride powder before supplying to the bipolar membrane device. It was possible to preferably carry out, and it was possible to prevent a decrease in the concentration of hydrofluoric acid.
【００６３】実施例２ 濃度30g/L のフッ酸（ＨＦ）、濃度220g/Lの硝酸（ＨＮ
Ｏ3)、及び濃度30g/Lの鉄を含む廃酸を、濃度112g/Lの
苛性カリ（ＫＯＨ）中で中和し、沈澱したＦｅ(ＯＨ)3
をフィルタープレスで除去後、質量5510g のＫＦを添加
してバイポーラ膜装置で処理したところ、当初の原水中
の濃度とほぼ同じ濃度である濃度29.8g/L のフッ酸と濃
度221g/Lの硝酸との混合酸が回収できた。 Example 2 Hydrofluoric acid (HF) having a concentration of 30 g / L and nitric acid (HN) having a concentration of 220 g / L
O 3 ), and a spent acid containing iron at a concentration of 30 g / L were neutralized in caustic potash (KOH) at a concentration of 112 g / L to precipitate Fe (OH) 3
After removing it with a filter press and adding 5510 g of KF and treating it with a bipolar membrane device, the concentration of hydrofluoric acid at a concentration of 29.8 g / L and the concentration of nitric acid at a concentration of 221 g / L, which are almost the same as those in the original raw water, The mixed acid with was recovered.
【００６４】本実施例においても、酸の濃度低下、特に
フッ酸の濃度低下を防止することができた。Also in this example, it was possible to prevent a decrease in the concentration of acid, particularly a decrease in the concentration of hydrofluoric acid.
【００６５】従って、本実施例においては、初回のバッ
チから所望濃度のフッ酸を回収できるため、装置の運転
の立ち上げ時間も短縮することができることなる。Therefore, in this embodiment, since the hydrofluoric acid having a desired concentration can be recovered from the first batch, the start-up time of the operation of the apparatus can be shortened.
【００６６】[0066]
【発明の効果】叙上のように、本発明においては、アル
カリでの中和工程で生ずる中性塩であって、回収される
混合酸を構成するアニオン成分のうち、混合酸中の全ア
ニオン成分に対して存在する比率が、濾液中の全アニオ
ン成分に対して存在する比率より低くなるアニオン成分
からなる中性塩を、たとえば硝フッ酸廃液の場合にはフ
ッ化カリウム等を、バイポーラ膜装置への供給前に予め
添加するため、そのバイポーラ膜装置通過後の、回収混
合酸のうちのフッ酸の濃度低下を防止できる。INDUSTRIAL APPLICABILITY As described above, according to the present invention, all the anions in the mixed acid, which are neutral salts produced in the step of neutralizing with an alkali, among the anionic components constituting the recovered mixed acid. A neutral salt composed of an anion component whose ratio to the components is lower than that to all the anion components in the filtrate, for example, potassium fluoride in the case of waste liquid of hydrofluoric acid is used as a bipolar membrane. Since it is added in advance before being supplied to the apparatus, it is possible to prevent a decrease in the concentration of hydrofluoric acid in the recovered mixed acid after passing through the bipolar membrane apparatus.
【００６７】従って、いわゆるバッチ運転の場合であっ
ても、従来のようにバッチ回数を重ねることなく、装置
の立ち上げ運転時から所望の濃度のフッ酸は得られるこ
ととなり、その結果、装置運転の立ち上げ時間を従来に
比べて大幅に短縮することができるという効果がある。Therefore, even in the case of so-called batch operation, hydrofluoric acid of a desired concentration can be obtained from the start-up operation of the apparatus without repeating the batch number as in the conventional case. The effect is that the startup time of can be significantly shortened compared to the conventional one.
【００６８】ちなみに、従来では装置の立ち上げに４バ
ッチ要しており、その４バッチそれぞれにフッ酸を補充
しなければ酸洗槽で再利用できなかったが、本発明では
再利用のためにフッ酸を補充することは不要であり、か
つ１バッチで立ち上げを可能とすることができた。By the way, conventionally, four batches were required to start up the apparatus, and each of the four batches could not be reused in the pickling tank unless supplemented with hydrofluoric acid. It was not necessary to replenish with hydrofluoric acid, and it was possible to start up in one batch.
【図１】一実施例の硝フッ酸廃液からの硝酸とフッ酸と
の分離回収装置の概略ブロック図。FIG. 1 is a schematic block diagram of an apparatus for separating and recovering nitric acid and hydrofluoric acid from a nitric hydrofluoric acid waste liquid according to an embodiment.
【図２】バイポーラ膜装置の内部構造を示す概略図。FIG. 2 is a schematic diagram showing the internal structure of a bipolar membrane device.
【図３】従来の硝酸とフッ酸との分離回収装置の概略ブ
ロック図。FIG. 3 is a schematic block diagram of a conventional device for separating and recovering nitric acid and hydrofluoric acid.
【図４】従来の廃酸中のフッ酸の濃度と回収フッ酸の濃
度との相関関係を示すグラフ。FIG. 4 is a graph showing the correlation between the concentration of hydrofluoric acid in conventional waste acid and the concentration of recovered hydrofluoric acid.
４…バイポーラ膜装置 ５…バイポーラ膜 ６…陽イオン交換膜 ７…陰イオン交換膜 4 ... Bipolar membrane device 5 ... Bipolar membrane 6 ... Cation exchange membrane 7 ... Anion exchange membrane
Claims (4)
で中和し金属等を沈澱分離した後、濾液をバイポーラ膜
(5) 、陽イオン交換膜(6) 、陰イオン交換膜(7) を備え
たバイポーラ膜装置(4) に供給して該バイポーラ膜装置
(4) から酸とアルカリとを分離し再生回収する硝フッ酸
廃液等の酸混合液の再生回収処理方法において、前記ア
ルカリでの中和工程で生ずる中性塩であって、回収され
る混合酸を構成するアニオン成分のうち、混合酸中の全
アニオン成分に対して存在する比率が、濾液中の全アニ
オン成分に対して存在する比率より低くなるアニオン成
分を含む中性塩を、前記バイポーラ膜装置(4) への供給
前に予め添加することを特徴とする硝フッ酸廃液等の酸
混合液の再生回収処理方法。1. A bipolar membrane prepared by neutralizing an acid mixture solution such as a nitric hydrofluoric acid waste solution with an alkali to precipitate and separate metals and the like, and then filtering the filtrate.
(5), a cation exchange membrane (6) and an anion exchange membrane (7) are supplied to a bipolar membrane device (4) to supply the bipolar membrane device.
(4) In the method for regenerating and recovering an acid mixture solution such as nitric-hydrofluoric acid waste solution, in which an acid and an alkali are separated and regenerated and recovered, a neutral salt generated in the neutralization step with the alkali is recovered and mixed. Of the anionic components that make up the acid, the ratio of the anionic component present relative to the total anionic components in the mixed acid is lower than the ratio present relative to the total anionic components in the filtrate, and a neutral salt containing an anionic component is added to the bipolar A method for regenerating and recovering an acid mixed liquid such as nitric hydrofluoric acid waste liquid, which is added in advance before being supplied to the membrane device (4).
に添加される請求項１記載の硝フッ酸廃液等の酸混合液
の再生回収処理方法。2. The method for regenerating and recovering an acid mixture solution such as a waste nitric-hydrofluoric acid waste solution according to claim 1, wherein the neutral salt is added after the step of neutralizing with an alkali.
２記載の硝フッ酸廃液等の酸混合液の再生回収処理方
法。3. The method for regenerating and recovering an acid mixed solution such as a nitric hydrofluoric acid waste solution according to claim 1 or 2, wherein the neutral salt is in a powder form.
求項１乃至３のいずれかに記載の硝フッ酸廃液等の酸混
合液の再生回収処理方法。4. The method for regenerating and recovering an acid mixture solution such as a nitric-hydrofluoric acid waste solution according to claim 1, wherein the neutral salt is potassium fluoride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33356395A JPH09176874A (en) | 1995-12-21 | 1995-12-21 | Method for regenerating and recovering acid liquid mixture such as waste nitric acid-hydrofluoric acid mixture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33356395A JPH09176874A (en) | 1995-12-21 | 1995-12-21 | Method for regenerating and recovering acid liquid mixture such as waste nitric acid-hydrofluoric acid mixture |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09176874A true JPH09176874A (en) | 1997-07-08 |
Family
ID=18267451
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33356395A Pending JPH09176874A (en) | 1995-12-21 | 1995-12-21 | Method for regenerating and recovering acid liquid mixture such as waste nitric acid-hydrofluoric acid mixture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09176874A (en) |
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| CN105859005A (en) * | 2016-05-10 | 2016-08-17 | 宝钢工程技术集团有限公司 | Method and system for treating stainless steel cold-rolling and pickling waste acid |
| CN109502858A (en) * | 2017-09-15 | 2019-03-22 | 上海江柘环境工程技术有限公司 | A kind of photovoltaic industry fluorine-contained wastewater treatment system and its processing method |
-
1995
- 1995-12-21 JP JP33356395A patent/JPH09176874A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100590715B1 (en) * | 2001-08-31 | 2006-06-15 | 주식회사 포스코 | Filtering system for clean pickling solution |
| JP2003071457A (en) * | 2001-09-04 | 2003-03-11 | Maezawa Ind Inc | Method for recovering mineral acid from mixed acid of boric acid and mineral acid |
| JP2006131982A (en) * | 2004-11-09 | 2006-05-25 | Jfe Steel Kk | Treatment method for pickling waste solution and treatment device for pickling waste solution |
| JP4544970B2 (en) * | 2004-11-09 | 2010-09-15 | Ｊｆｅスチール株式会社 | Processing method for pickling waste liquid and processing equipment for pickling waste liquid |
| CN100441520C (en) * | 2006-01-24 | 2008-12-10 | 常州市裕和金属材料有限公司 | High-efficiency environment-friendly acid-mixed plating removal liquor |
| CN100361905C (en) * | 2006-04-28 | 2008-01-16 | 常州市裕和金属材料有限公司 | Method for treating waste acid liquor |
| WO2010092946A1 (en) * | 2009-02-13 | 2010-08-19 | 株式会社神鋼環境ソリューション | Method for processing waste water containing fluorine and silicon, method for producing calcium fluoride, and facility for processing fluorine-containing waste water |
| CN105859005A (en) * | 2016-05-10 | 2016-08-17 | 宝钢工程技术集团有限公司 | Method and system for treating stainless steel cold-rolling and pickling waste acid |
| CN109502858A (en) * | 2017-09-15 | 2019-03-22 | 上海江柘环境工程技术有限公司 | A kind of photovoltaic industry fluorine-contained wastewater treatment system and its processing method |
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