JPH07166383A - Method for recovering acid in apparatus for pickling metallic strip and apparatus therefor - Google Patents
Method for recovering acid in apparatus for pickling metallic strip and apparatus thereforInfo
- Publication number
- JPH07166383A JPH07166383A JP31211493A JP31211493A JPH07166383A JP H07166383 A JPH07166383 A JP H07166383A JP 31211493 A JP31211493 A JP 31211493A JP 31211493 A JP31211493 A JP 31211493A JP H07166383 A JPH07166383 A JP H07166383A
- Authority
- JP
- Japan
- Prior art keywords
- pickling
- acid
- tank
- nitric acid
- pickling tank
- 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.)
- Granted
Links
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
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、金属帯、特にステンレ
ス鋼帯を酸洗するに際し、硝酸と電極作用とによって酸
洗する第１酸洗槽と、硝酸とフッ酸との混酸によって酸
洗する第２酸洗槽とを備えた酸洗装置における酸回収方
法および装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a first pickling tank for pickling metal strips, especially stainless steel strips, by pickling nitric acid and electrode action, and pickling with a mixed acid of nitric acid and hydrofluoric acid. The present invention relates to a method and an apparatus for recovering an acid in a pickling apparatus including a second pickling tank.
【０００２】[0002]
【従来の技術】金属帯は、熱間圧延や焼鈍処理などによ
ってその表面に金属酸化物を主成分とするスケールが付
着しており、これが後処理で不都合を生じ、製品品質に
悪影響を及ぼすため、脱スケール処理がなされる。2. Description of the Related Art A metal strip has a scale mainly containing a metal oxide attached to its surface by hot rolling, annealing, etc., which causes inconvenience in post-treatment and adversely affects product quality. , The descaling process is performed.
【０００３】この脱スケール処理は、硝酸ナトリウムな
どの中性塩の浴中へ浸漬する前処理を行った後、金属帯
がＳＵＳ ４３０に代表されるフェライト系のステンレ
ス鋼帯の場合は、硝酸と電極作用とによって酸洗され、
ＳＵＳ ３０４に代表されるオーステナイト系のステン
レス鋼帯の場合は、硝酸とフッ酸との混酸によって酸洗
される。また他の金属帯、たとえばめっき用原板として
のステンレス鋼帯やステンレス鋼の範疇には属さない高
Ｎｉ合金鋼帯などでは、前記両方の酸洗液で酸洗する必
要がある。そして脱スケールを完全に行うためには、こ
れらの酸洗液の酸濃度、フッ素イオン濃度および金属イ
オン濃度を一定の範囲に保持しなければならない。従来
はこれらの濃度を測定し、特に金属帯の酸洗によって増
加する金属イオン濃度を測定し、これを一定にするため
に、酸洗液の一部を抜取り、硝酸または硝酸とフッ酸を
補給している。硝酸とフッ酸との混酸の濃度管理につい
ての先行技術は、たとえば特公昭６０−３５９９５に示
されている。In this descaling treatment, after the pretreatment of immersing in a bath of a neutral salt such as sodium nitrate, when the metal strip is a ferritic stainless steel strip represented by SUS 430, it is treated with nitric acid. Pickled by electrode action,
In the case of an austenitic stainless steel strip represented by SUS 304, it is pickled with a mixed acid of nitric acid and hydrofluoric acid. Further, for other metal strips such as a stainless steel strip as a plating original plate or a high Ni alloy steel strip not belonging to the category of stainless steel, it is necessary to perform pickling with both of the above pickling solutions. In order to perform descaling completely, the acid concentration, fluorine ion concentration and metal ion concentration of these pickling solutions must be kept within a certain range. Conventionally, these concentrations were measured, especially the metal ion concentration increased by pickling of the metal band was measured, and in order to keep it constant, part of the pickling solution was withdrawn and nitric acid or nitric acid and hydrofluoric acid were replenished. is doing. The prior art for controlling the concentration of a mixed acid of nitric acid and hydrofluoric acid is disclosed, for example, in Japanese Patent Publication No. 60-35995.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、前記従
来技術では、金属イオンを低下させる目的で酸洗液を抜
取り、これを廃棄すると有効な酸も同時に系外に排出さ
れてしまい、硝酸やフッ酸の使用量が増加するという問
題がある。また硝酸やフッ酸は、そのまま廃棄できず、
中和するなどの処理を要するという問題がある。However, in the above-mentioned prior art, if the pickling solution is withdrawn for the purpose of lowering the metal ions and discarded, the effective acid is also discharged out of the system at the same time, and nitric acid or hydrofluoric acid is discharged. However, there is a problem that the usage amount of is increased. Also, nitric acid and hydrofluoric acid cannot be discarded as they are,
There is a problem that treatment such as neutralization is required.
【０００５】本発明の目的は、硝酸によって酸洗する第
１酸洗槽と、硝酸とフッ酸との混酸によって酸洗する第
２酸洗槽とを備えた酸洗装置において、抜取った金属イ
オンを含む酸洗液中の金属イオンを除去し、酸を回収す
る方法および装置を提供するものである。An object of the present invention is to provide a pickling apparatus equipped with a first pickling tank for pickling with nitric acid and a second pickling tank for pickling with a mixed acid of nitric acid and hydrofluoric acid. It is intended to provide a method and an apparatus for recovering an acid by removing metal ions in a pickling solution containing ions.
【０００６】[0006]
【課題を解決するための手段】本発明は、硝酸によって
金属帯を酸洗する第１酸洗槽と、硝酸とフッ酸との混酸
によって酸洗する第２酸洗槽とを備えた酸洗装置におい
て、第１および第２酸洗槽の酸洗液を槽外に導き、陰イ
オン交換膜から成る酸回収手段によって金属イオンを除
去して、硝酸およびフッ酸を回収し、この回収した回収
酸を第２酸洗槽に返すことを特徴とする金属帯の酸洗装
置における酸回収方法である。SUMMARY OF THE INVENTION The present invention comprises a first pickling tank for pickling a metal strip with nitric acid and a second pickling tank for pickling with a mixed acid of nitric acid and hydrofluoric acid. In the apparatus, the pickling solutions in the first and second pickling tanks are introduced to the outside of the tank, the metal ions are removed by an acid recovery means composed of an anion exchange membrane, and nitric acid and hydrofluoric acid are recovered. A method for recovering an acid in a pickling apparatus for a metal strip, wherein the acid is returned to the second pickling tank.
【０００７】また本発明は、前記第１および第２酸洗槽
内の酸洗液の酸濃度、フッ素イオン濃度および金属イオ
ン濃度を測定し、これらが定められた濃度範囲になるよ
うに、第１および第２酸洗槽の酸洗液を槽外に導き、第
１酸洗槽に硝酸および水を、第２酸洗槽に硝酸、水、フ
ッ酸および前記回収酸を補給することを特徴とする。In the present invention, the acid concentration, the fluorine ion concentration and the metal ion concentration of the pickling solution in the first and second pickling tanks are measured, and the acid concentration, the fluorine ion concentration and the metal ion concentration are determined so that they fall within a predetermined concentration range. The pickling solutions of the first and second pickling tanks are introduced to the outside of the tank, and nitric acid and water are supplied to the first pickling tank, and nitric acid, water, hydrofluoric acid and the recovered acid are supplied to the second pickling tank. And
【０００８】また本発明は、前記金属帯がステンレス鋼
帯であることを特徴とする。Further, the present invention is characterized in that the metal strip is a stainless steel strip.
【０００９】また本発明は、硝酸を貯留する酸洗槽内に
電極を設け、その電極間を連続通板する金属帯を浸漬す
る第１酸洗槽と、硝酸とフッ酸を貯留する酸洗槽内に、
連続通板する金属帯を浸漬する第２酸洗槽と、前記第１
酸洗槽または第２酸洗槽内の酸洗液の一部を抜出して、
各酸洗液の酸濃度、フッ素イオン濃度および金属イオン
濃度を分析する分析手段と、酸洗液を貯留する中継槽
と、前記第１酸洗槽の酸洗液を前記中継槽に送る第１ポ
ンプと、前記第２酸洗槽の酸洗液を前記中継槽に送る第
２ポンプと、前記中継槽の酸洗液を第３ポンプを介して
受入れ、酸洗液中の金属イオンを除去して酸を回収する
陰イオン交換膜から構成される酸回収手段と、回収され
た回収酸を貯留する回収酸槽と、硝酸、および水を第１
酸洗槽に供給する第１供給手段と、硝酸、フッ酸、水お
よび回収酸槽の回収酸を第２酸洗槽に供給する第２供給
手段と、前記分析手段からの第１酸洗槽の酸洗液の各成
分濃度が定められた濃度範囲になるように、第１ポンプ
および第１供給手段を制御し、第２酸洗槽の各成分濃度
が定められた濃度範囲になるように第２ポンプおよび第
２供給手段を制御する制御手段とから成ることを特徴と
する金属帯の酸洗装置である。Further, the present invention provides a first pickling tank in which an electrode is provided in a pickling tank for storing nitric acid, and a metal strip continuously passing between the electrodes is immersed, and a pickling tank for storing nitric acid and hydrofluoric acid. In the tank,
A second pickling tank for immersing a continuous metal strip, and the first
Withdraw a part of the pickling solution in the pickling tank or the second pickling tank,
An analyzing means for analyzing the acid concentration, the fluoride ion concentration and the metal ion concentration of each pickling solution, a relay tank for storing the pickling solution, and a first pickling solution for feeding the pickling solution from the first pickling tank to the relay tank. A pump, a second pump that sends the pickling solution from the second pickling tank to the relay tank, and a pickling solution from the relay tank through a third pump to remove metal ions in the pickling solution. Acid recovery means configured of an anion exchange membrane for recovering acid, a recovery acid tank for storing the recovered recovery acid, nitric acid, and water.
First supply means for supplying to the pickling tank, second supply means for supplying nitric acid, hydrofluoric acid, water and recovered acid from the recovered acid tank to the second pickling tank, and first pickling tank from the analyzing means The first pump and the first supply means are controlled so that the concentration of each component of the pickling solution of No. 1 is within the determined concentration range, and the concentration of each component of the second pickling tank is within the determined concentration range. A metal strip pickling device comprising a control means for controlling a second pump and a second supply means.
【００１０】[0010]
【作用】本発明に従えば、第１酸洗槽には硝酸が、第２
酸洗槽には硝酸とフッ酸との混酸がそれぞれ用いられて
おり、両方の酸洗液を共通の中継槽を介して酸回収手段
に導き、ここで酸洗液中の金属イオンをイオン交換膜で
除き、硝酸とフッ酸とを回収し、回収酸を第２酸洗槽の
補給液に用いている。これによって、第２酸洗槽に補給
する硝酸とフッ酸の量を少なくすることができ、また酸
洗槽が２系統あるにかかわらず、中継槽、酸回収手段を
１系統にすることができる。According to the present invention, the first pickling tank contains nitric acid and the second pickling tank contains nitric acid.
A mixed acid of nitric acid and hydrofluoric acid is used in the pickling tank, and both pickling solutions are led to the acid recovery means through a common relay tank, where metal ions in the pickling solution are ion-exchanged. Nitric acid and hydrofluoric acid are recovered by removing with a membrane, and the recovered acid is used as a replenisher for the second pickling tank. As a result, the amounts of nitric acid and hydrofluoric acid supplied to the second pickling tank can be reduced, and even if there are two pickling tanks, the relay tank and the acid recovery means can be provided in one system. .
【００１１】また第１および第２酸洗槽の酸洗液の抜取
りは、各酸洗槽の主として金属イオン濃度がある範囲に
なるように行われる。これによって第１および第２酸洗
槽の両酸洗液の金属イオンを一定の範囲になるように制
御することができる。The pickling solution in the first and second pickling tanks is withdrawn so that the metal ion concentration of each pickling tank is within a certain range. This makes it possible to control the metal ions of both the pickling solutions in the first and second pickling tanks to fall within a certain range.
【００１２】[0012]
【実施例】以下、実施例でもって本発明をより具体的に
説明するが、本発明はこれに限定されるものではない。The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
【００１３】図１（１）は、本発明の一実施例で、連続
通板する金属帯１ａが第１酸洗槽１１と第２酸洗槽１２
とを浸漬通過する場合の酸洗槽１１，１２と金属帯１ａ
との関係を示す図である。金属帯１ａがＳＵＳ ３０４
に代表されるオーステナイト系のステンレス鋼帯である
場合は、第１酸洗槽１１の電極１３に通電せずに２０〜
３０ｍ／分の速度で通板して、硝酸とフッ酸との混酸で
酸洗を行う。図１（２）は、本発明の一実施例で、連続
通板する金属帯１ｂが第１酸洗槽１１のみを浸漬通過す
る場合の酸洗槽１１，１２と金属帯１ｂとの関係を示す
図である。金属帯１ｂがＳＵＳ ４３０に代表されるフ
ェライト系のステンレス鋼帯である場合は、第１酸洗槽
１１の電極１３に通電して２０〜３０ｍ／分の速度で通
板して、硝酸で酸洗を行う。この場合、第２酸洗槽１２
中の浸漬ローラ３，４を第２酸洗槽１２の上に持上げる
ことによって、第２酸洗槽２に金属帯１ｂが浸漬されな
いようにする。その他のローラ５〜１０は、固定されて
いる。なお各酸洗槽１１，１２の長さは、たとえば１０
〜３０ｍで、金属帯１が各酸洗槽に浸漬している時間は
１分前後である。FIG. 1 (1) shows an embodiment of the present invention, in which a metal strip 1a which is continuously threaded has a first pickling tank 11 and a second pickling tank 12.
Pickling tanks 11 and 12 and metal strip 1a when passing through
It is a figure which shows the relationship with. Metal strip 1a is SUS 304
In the case of an austenitic stainless steel strip represented by, the electrode 13 of the first pickling bath 11 is energized for 20 to 20%.
The plate is passed at a speed of 30 m / min and pickled with a mixed acid of nitric acid and hydrofluoric acid. FIG. 1 (2) shows an embodiment of the present invention, showing a relationship between the pickling tanks 11 and 12 and the metal band 1b when the metal strip 1b continuously threaded passes through the first pickling tank 11 by immersion. FIG. When the metal strip 1b is a ferritic stainless steel strip typified by SUS 430, the electrode 13 of the first pickling tank 11 is energized to pass through the strip at a speed of 20 to 30 m / min, and acid is added with nitric acid. Do a wash. In this case, the second pickling tank 12
By lifting the dipping rollers 3 and 4 therein above the second pickling tank 12, the metal strip 1b is prevented from being immersed in the second pickling tank 2. The other rollers 5 to 10 are fixed. The length of each pickling tank 11 and 12 is, for example, 10
At about 30 m, the time during which the metal strip 1 is immersed in each pickling tank is about 1 minute.
【００１４】図２は、酸洗液の流れを示す系統図であ
る。ＳＵＳ ４３０で代表されるフェライト系のステン
レス鋼帯１ｂは、第１酸洗槽１１のみを浸漬通過される
ので、ここで酸洗処理される。熱間圧延や焼鈍処理など
によってステンレス鋼帯表面に生じた金属酸化物を主成
分とするスケールは、硝酸によって溶解され、式（Ｉ）
で示すように第２鉄イオンを主とする金属イオンを生じ
る。FIG. 2 is a system diagram showing the flow of the pickling solution. The ferritic stainless steel strip 1b represented by SUS 430 is soaked and passed through only the first pickling tank 11, so that it is pickled here. The metal oxide-based scale produced on the surface of the stainless steel strip by hot rolling, annealing, etc. is dissolved by nitric acid to obtain the formula (I).
As shown in, metal ions mainly containing ferric ions are produced.
【００１５】 ２Ｆｅ＋６Ｈ+→２Ｆｅ3+＋３Ｈ2 …（Ｉ） 実際には金属イオンとして、Ｆｅ3+の他にＦｅ2+，Ｃｒ
3+，Ｃｒ6+，Ｎｉ+2などが混在している。酸洗処理が進
むに従って、酸洗液中の硝酸濃度に対応する水素イオン
濃度（Ｈ+）が低下し、Ｆｅ3+などの金属イオンが増加
する。硝酸濃度は、たとえば当初２００ｇ／ｌである
が、これが５０ｇ／ｌ以下となると、また当初ほとんど
含まれなかった金属イオンが２００ｇ／ｌを超えると、
酸洗効果が低下し規定の速度で通板したのでは酸洗処理
ができなくなる。したがって分析手段４０によって、間
欠的に、たとえば１０分毎に第１酸洗槽１１の酸洗液を
分析し、硝酸濃度が５０ｇ／ｌを超えるように、また金
属イオン濃度が２００ｇ／ｌ以下になるように酸洗液の
一部を中継槽２８に抜取り、硝酸を補給する。具体的に
は、金属イオン濃度が２００ｇ／ｌを超えるときには、
第１ポンプ１６で酸洗液の一部を抜取り、その量に見合
う硝酸と水とを硝酸供給バルブ１８と水供給バルブ１７
とから成る第１供給手段によって補給する。硝酸と水と
の補給割合は、第１酸洗槽１１全体の硝酸濃度が５０ｇ
／ｌを超えるように決められる。2Fe + 6H + → 2Fe 3+ + 3H 2 (I) Actually, as the metal ions, in addition to Fe 3+ , Fe 2+ , Cr
3+ , Cr 6+ , Ni +2, etc. are mixed. As the pickling treatment progresses, the hydrogen ion concentration (H + ) corresponding to the nitric acid concentration in the pickling solution decreases, and metal ions such as Fe 3+ increase. The nitric acid concentration is, for example, 200 g / l at the beginning, but when the nitric acid concentration is 50 g / l or less, and when the metal ions which are hardly contained initially exceed 200 g / l,
If the pickling effect is reduced and the plate is passed at a specified speed, the pickling process cannot be performed. Therefore, the analysis means 40 intermittently analyzes the pickling solution in the first pickling tank 11 every 10 minutes, for example, so that the nitric acid concentration exceeds 50 g / l and the metal ion concentration falls below 200 g / l. So that a part of the pickling solution is drawn into the relay tank 28 and nitric acid is replenished. Specifically, when the metal ion concentration exceeds 200 g / l,
A part of the pickling solution is extracted by the first pump 16, and nitric acid and water corresponding to the amounts are supplied to the nitric acid supply valve 18 and the water supply valve 17.
It is replenished by the first supply means consisting of. The replenishment rate of nitric acid and water is such that the nitric acid concentration of the entire first pickling tank 11 is 50 g.
It is decided to exceed / l.
【００１６】酸洗される金属帯がＳＵＳ ３０４で代表
されるオーステナイト系のステンレス鋼帯１ａの場合、
ステンレス鋼帯１ａは第１酸洗槽１１と第２酸洗槽１２
とを浸漬通過するが、第１酸洗槽１１では電極１３に通
電されていないので、ステンレス鋼帯１ａは主として第
２酸洗槽１２で酸洗される。熱間圧延や焼鈍処理などに
よってステンレス鋼帯表面に生じた金属酸化物を主成分
とするスケールは、オーステナイト系のステンレスの場
合、硝酸とフッ酸との混酸によって溶解処理される。そ
して酸洗処理が進むに従って酸洗液中の硝酸とフッ酸と
の混酸の濃度（Ｈ+）が低下し、Ｆｅ3+などの金属イオ
ンが増加する。硝酸濃度は、たとえば当初１００ｇ／ｌ
であり、フッ酸濃度は１０ｇ／ｌであるが、これらがそ
れぞれ４０ｇ／ｌ、２ｇ／ｌ以下となると、また当初ほ
とんど含まれなかった金属イオンが２００ｇ／ｌを超え
ると、酸洗効果が低下し、規定の速度で通板したのでは
酸洗処理ができなくなる。したがって分析手段４０によ
って、間欠的に、たとえば１０分毎に第２酸洗槽１２の
酸洗液を分析し、硝酸とフッ酸との濃度をそれぞれ４０
ｇ／ｌ、２ｇ／ｌを超えるように、また金属イオン濃度
が２００ｇ／ｌ以下になるように酸洗液の一部を第２ポ
ンプ２１によって抜取り、その量に見合う硝酸とフッ酸
との溶液を第２供給手段によって補給する。回収酸槽３
７に回収酸がない場合は、この溶液は第１酸洗槽１１と
同様に、硝酸とフッ酸と水とが第２酸洗槽１２全体の硝
酸濃度とフッ酸濃度とがそれぞれ４０ｇ／ｌ，２ｇ／ｌ
を超えるように配合供給される。しかし回収酸槽３７に
回収酸があれば、回収酸が補給される。回収酸を補給し
たのではフッ酸が不足するときは、回収酸とフッ酸とが
補給される。When the metal strip to be pickled is an austenitic stainless steel strip 1a represented by SUS 304,
The stainless steel strip 1a includes a first pickling tank 11 and a second pickling tank 12
Although it passes through by immersion, since the electrode 13 is not energized in the first pickling tank 11, the stainless steel strip 1a is mainly pickled in the second pickling tank 12. In the case of austenitic stainless steel, the scale containing a metal oxide as a main component, which is produced on the surface of the stainless steel strip by hot rolling or annealing, is dissolved by a mixed acid of nitric acid and hydrofluoric acid. Then, as the pickling treatment progresses, the concentration (H + ) of the mixed acid of nitric acid and hydrofluoric acid in the pickling solution decreases, and the amount of metal ions such as Fe 3+ increases. The nitric acid concentration is, for example, 100 g / l at the beginning.
The concentration of hydrofluoric acid is 10 g / l, but when these are 40 g / l, 2 g / l or less, respectively, and when the metal ions that were initially hardly contained exceed 200 g / l, the pickling effect is reduced. However, pickling cannot be performed if the plates are passed at a specified speed. Therefore, the pickling solution in the second pickling tank 12 is intermittently analyzed by the analyzing means 40, for example, every 10 minutes, and the concentrations of nitric acid and hydrofluoric acid are respectively 40%.
g / l, a part of the pickling solution is extracted by the second pump 21 so that the metal ion concentration becomes 200 g / l or less, and a solution of nitric acid and hydrofluoric acid corresponding to the amount. Is replenished by the second supply means. Recovery acid tank 3
When there is no recovered acid in No. 7, as in the case of the first pickling tank 11, this solution contains nitric acid, hydrofluoric acid, and water, and the nitric acid concentration and hydrofluoric acid concentration of the entire second pickling tank 12 are 40 g / l, respectively. , 2 g / l
It is compounded and supplied to exceed. However, if the recovered acid tank 37 has recovered acid, the recovered acid is replenished. When the recovered acid is replenished and the hydrofluoric acid is insufficient, the recovered acid and the hydrofluoric acid are replenished.
【００１７】次に中継槽２８に貯留された第１および第
２酸洗槽１１，１２から抜取られた酸洗液の処理につい
て説明する。中継槽２８に貯留された液は、まだ相当の
酸分を含んでいる。たとえば第１酸洗槽から抜取られた
液は、５０ｇ／ｌの硝酸分を、また第２酸洗槽から抜取
られた液は４０ｇ／ｌの硝酸分と２ｇ／ｌのフッ酸を含
んでいる。これを第３ポンプ３６で加圧し、酸回収手段
３０で回収し、回収酸槽３７に貯留する。図３は酸回収
手段３０の原理を説明するための説明図である。酸回収
手段３０は、隔壁３１で多くの細長い部屋３２に仕切ら
れた直方体の容器である。各部屋３２は、さらに陰イオ
ン交換膜３３によってＭ部とＮ部とに仕切られている。
Ｍ部には、第３ポンプから中継槽に抜取られた金属イオ
ンを含んだ酸洗液が供給され、酸を回収されて廃酸が廃
酸処理装置３８へ送られる。Ｎ部には、水が供給され、
酸を回収して回収酸が回収酸槽３７に送られる。陰イオ
ン交換膜３３は、陰イオンのみを透過し、陽イオンは透
過しないので、Ｍ部に含まれる陰イオンＮＯ-，Ｆ-はＮ
部に移動し、Ｎ部の水中で僅かに電離している水素イオ
ン（Ｈ+）と水酸イオン（ＯＨ-）の電離を促進する。Ｎ
部で生じたＯＨ-は、陰イオン交換膜を透過してＭ部に
移る。このようにして、Ｍ部に供給された硝酸イオン
（ＮＯ3 -）、フッ素イオン（Ｆ-）は、Ｎ部に移り回収
される。これに対しＭ部に供給される金属イオン（陽イ
オン）は、陰イオン交換膜３３を透過することができ
ず、Ｍ部の出口から廃酸処理装置３７に送られる。硝酸
とフッ酸との混酸に好都合に用いられる陰イオン交換膜
３３としては、たとえば徳山曹達株式会社製のネオセプ
タＡＭ−１がある。酸回収手段３０は、陰イオン交換膜
３３の性質から交換液の流量は、一定であることが望ま
しいので、中継槽２８と回収酸槽３７とをその前後に置
いている。したがって第３ポンプ３６は、中継槽２８が
ある水位以上で稼働し、それよりも低いある水位以下で
停止するものが好ましく、酸回収手段に供給される水の
供給バルブ３４も第３ポンプの稼働停止に従って開閉す
るものが好ましい。なお、酸回収手段３０によって、た
とえば表１に示すように酸成分が回収される。Next, the treatment of the pickling solution withdrawn from the first and second pickling tanks 11 and 12 stored in the relay tank 28 will be described. The liquid stored in the relay tank 28 still contains a considerable amount of acid. For example, the liquid extracted from the first pickling tank contains 50 g / l nitric acid, and the liquid extracted from the second pickling tank contains 40 g / l nitric acid and 2 g / l hydrofluoric acid. . This is pressurized by the third pump 36, recovered by the acid recovery means 30, and stored in the recovered acid tank 37. FIG. 3 is an explanatory diagram for explaining the principle of the acid recovery means 30. The acid recovery means 30 is a rectangular parallelepiped container partitioned by a partition wall 31 into many elongated chambers 32. Each room 32 is further partitioned into an M section and an N section by an anion exchange membrane 33.
The pickling solution containing the metal ions extracted from the third pump to the relay tank is supplied to the M section, the acid is recovered, and the waste acid is sent to the waste acid treatment device 38. Water is supplied to the N section,
The acid is recovered and the recovered acid is sent to the recovery acid tank 37. Since the anion exchange membrane 33 transmits only anions and not cations, the anions NO − and F − contained in the M portion are N.
Part of the water, and promotes ionization of hydrogen ions (H + ) and hydroxide ions (OH − ) that are slightly ionized in the water of the N part. N
The OH − generated in the part permeates the anion exchange membrane and moves to the part M. In this way, the nitrate ions (NO 3 − ) and fluorine ions (F − ) supplied to the M section are transferred to the N section and collected. On the other hand, the metal ions (cations) supplied to the M part cannot pass through the anion exchange membrane 33, and are sent to the waste acid treatment device 37 from the outlet of the M part. An example of the anion exchange membrane 33 that is conveniently used for a mixed acid of nitric acid and hydrofluoric acid is Neoceptor AM-1 manufactured by Tokuyama Soda Co., Ltd. Since the acid recovery means 30 desirably has a constant flow rate of the exchange liquid due to the property of the anion exchange membrane 33, the relay tank 28 and the recovery acid tank 37 are placed in front of and behind it. Therefore, it is preferable that the third pump 36 operates at a certain water level or lower than the relay tank 28 and stops at a certain water level lower than that, and the water supply valve 34 supplied to the acid recovery means also operates the third pump. Those that open and close when stopped are preferable. The acid component is recovered by the acid recovery means 30 as shown in Table 1, for example.
【００１８】[0018]
【表１】 [Table 1]
【００１９】次に第１および第２酸洗液槽１１，１２内
の酸洗液の分析手段４０について説明する。使用してい
る酸洗槽１１または１２内の液は、一定時間毎、たとえ
ば１０分毎に、両方の酸洗槽を使用しているときには、
交互に、したがって５分毎に分析することになる。図４
は、第２酸洗槽１２と分析手段４０との関係を示す図で
ある。この関係は第１酸洗槽１１についても同様である
が、フッ酸を用いないのでフッ素イオンの分析は行わな
い。バルブＶ２を開きバルブＶ１を閉じることによって
第２酸洗槽１２内の液は、滴定槽４１に一定量たとえば
１００ｍｌが定量ポンプ４２によって抜出される。滴定
槽４１では、まずフッ素イオン電極４５によってフッ素
イオン濃度が測定される。フッ素イオン濃度の測定を滴
定槽４１内で行うことによって、簡単にかつ測定時間を
大幅に短縮できる。これが終われば、滴定槽４１内の液
の大部分たとえば９０ｍｌは定量ポンプ４３によって第
２酸洗槽１２内へ戻される。次に希釈用の所定量の水が
バルブＶ４を介して滴定槽４１に補給され、撹拌機４４
によって希釈された液を撹拌しながらバルブＶ５を開い
てアルカリ滴定液４８で滴定する。滴定時には、滴定槽
４１内の液の温度を温度計４６で、また電気伝導度を電
気伝導度計４７で測定し、遊離硝酸の濃度と金属イオン
濃度を計算し、滴定が終われば、滴定槽４１内からバル
ブＶ６を開いて液を排出する。Next, the means 40 for analyzing the pickling solution in the first and second pickling solution tanks 11 and 12 will be described. The liquid used in the pickling tank 11 or 12 is used at regular intervals, for example, every 10 minutes, when both pickling tanks are used.
Alternately, therefore every 5 minutes will be analyzed. Figure 4
FIG. 4 is a diagram showing a relationship between the second pickling tank 12 and the analyzing means 40. This relationship is the same for the first pickling tank 11, but since hydrofluoric acid is not used, no fluorine ion analysis is performed. By opening the valve V2 and closing the valve V1, a fixed amount of the liquid in the second pickling tank 12, for example, 100 ml, is extracted by the metering pump 42. In the titration tank 41, the fluorine ion electrode 45 first measures the fluorine ion concentration. By measuring the fluorine ion concentration in the titration tank 41, the measurement time can be shortened easily and greatly. When this is finished, most of the liquid in the titration tank 41, for example, 90 ml, is returned to the second pickling tank 12 by the metering pump 43. Next, a predetermined amount of water for dilution is supplied to the titration tank 41 via the valve V4, and the stirrer 44
The valve V5 is opened with stirring the liquid diluted by and titrated with the alkali titration liquid 48. At the time of titration, the temperature of the liquid in the titration tank 41 is measured by the thermometer 46, and the electric conductivity is measured by the electric conductivity meter 47, and the concentration of free nitric acid and the metal ion concentration are calculated. The valve V6 is opened from inside 41 to discharge the liquid.
【００２０】ここで硝酸とフッ酸との混酸の酸洗液中の
遊離硝酸、遊離フッ酸、金属イオン濃度を定量するため
に行うアルカリ滴定液４８で滴定する測定原理について
説明する。Here, the measurement principle of titration with the alkali titration liquid 48 for quantifying the concentrations of free nitric acid, free hydrofluoric acid and metal ions in the pickling solution of a mixed acid of nitric acid and hydrofluoric acid will be described.
【００２１】金属イオンを含む硝酸とフッ酸との混酸の
酸洗液を、電気伝導度と温度を測定しながらアルカリ滴
定液４８で滴定すると、図５に示すような関係曲線が得
られる。図中Ｌ１は縦軸に電気伝導度（１／Ω）を、横
軸に常時一定容量のアルカリ滴定液４８を滴下したとき
の滴定時間（ｓｅｃ）を表示した曲線で、この電気伝導
度は滴定における硝酸の中和が完了すると上昇する（こ
の電気伝導度の場合、上昇すると、図中の縦軸で下方へ
下がるように図示される）。When a pickling solution of a mixed acid of nitric acid containing metal ions and hydrofluoric acid is titrated with an alkali titration solution 48 while measuring electric conductivity and temperature, a relationship curve as shown in FIG. 5 is obtained. In the figure, L1 is a curve in which the vertical axis represents the electric conductivity (1 / Ω) and the horizontal axis represents the titration time (sec) when a constant volume of the alkali titrant 48 is constantly dripped. It rises when the neutralization of nitric acid in is completed (in the case of this electric conductivity, when it rises, it is shown as falling on the vertical axis in the figure).
【００２２】これは次のような理由による。次の式（Ｉ
Ｉ）に示す遊離硝酸およびフッ酸と金属、代表として鉄
の反応で生じたフッ化第２鉄の平衡反応において、滴定
前の液が酸性であるときには、この反応が左から右へ進
み難解離性の化合物であるフッ酸（ＨＦ）が生成する。This is for the following reason. The following formula (I
In the equilibrium reaction of ferric fluoride produced by the reaction of free nitric acid and hydrofluoric acid with a metal, typically iron, as shown in I), when the solution before titration is acidic, this reaction proceeds from left to right, causing difficult dissociation. Hydrofluoric acid (HF), which is a volatile compound, is produced.
【００２３】 ３ＨＮＯ3＋ＦｅＦ3→Ｆｅ（ＮＯ3）3＋３ＨＦ …（ＩＩ） そして次の式（ＩＩＩ）に示すような、たとえば水酸化
ナトリウム水溶液のアルカリ滴定液４８を用いて滴定
し、硝酸の中和が完了すると、引き続いて滴下するこの
アルカリ滴定液４８によって、前記式（ＩＩ）において
生成した難解離性の化合物であるフッ酸（ＨＦ）が、今
度は式（ＩＶ）に示すように、解離度の高いＮａＦを生
成し変化するので、前述した如く、この電気伝導度が上
昇するためである。3HNO 3 + FeF 3 → Fe (NO 3 ) 3 + 3HF (II) Then, titration is performed using an alkaline titration solution 48 of, for example, an aqueous sodium hydroxide solution, as shown in the following formula (III), and then nitric acid is added. When the addition is completed, the alkaline titrant solution 48, which is subsequently added dropwise, dissociates the hardly dissociative compound hydrofluoric acid (HF) generated in the above formula (II), as shown in the formula (IV). This is because, since NaF having a high degree of generation is generated and changed, the electric conductivity is increased as described above.
【００２４】 ＨＮＯ3＋ＮａＯＨ→ＮａＮＯ3＋Ｈ2Ｏ …（ＩＩＩ） ＨＦ＋ＮａＯＨ→ＮａＦ＋Ｈ2Ｏ …（ＩＶ） さらに引き続いてこのアルカリ滴定液４８を滴下するこ
とによって、この式（ＩＶ）に示すように生成したフッ
酸（ＨＦ）の中和反応が完了すると、今度は式（Ｖ）に
示すように、液中に存在する第２鉄イオンで代表される
金属イオンとこのアルカリ滴定液４８との反応によっ
て、難解離性の水酸化第２鉄が生成するようになる。HNO 3 + NaOH → NaNO 3 + H 2 O (III) HF + NaOH → NaF + H 2 O (IV) Further, the alkali titrant 48 was added dropwise to produce as shown in the formula (IV). When the neutralization reaction of hydrofluoric acid (HF) is completed, this time, as shown in formula (V), the reaction between the metal ion represented by ferric ion present in the liquid and the alkali titration liquid 48 causes Ferric hydroxide, which is hard to dissociate, is generated.
【００２５】 Ｆｅ3+＋３ＮａＯＨ→Ｆｅ（ＯＨ）3＋３Ｎａ+ …（Ｖ） したがって、図５に示す電気伝導度Ｌ１は、大きくはな
いが上昇傾向（図中、下方へ）を示し漸次上昇し続ける
が、この式（Ｖ）に示す反応が完了してしまうと、今度
は液中に解離度の高い水酸化ナトリウム水溶液のアルカ
リ滴定液４８自体が増加していくので、この上昇傾向が
強まり、その傾きが大きくなる。Fe 3+ + 3NaOH → Fe (OH) 3 + 3Na + (V) Therefore, the electrical conductivity L1 shown in FIG. 5 shows a rising tendency (downward in the figure) and continues to rise gradually. However, when the reaction represented by the formula (V) is completed, this time, the alkaline titration liquid 48 of the sodium hydroxide aqueous solution having a high dissociation degree itself increases, so that the upward tendency is intensified. The inclination increases.
【００２６】このような一連の化学反応において滴定槽
４１内の液温は、この図５の横軸は前記Ｌ１と同じで、
縦軸に液温度（℃）を表示した曲線Ｌ２で示すように、
前記式（ＩＩ）そして式（ＩＩＩ）、式（ＩＶ）に示す
反応に従って、硝酸とフッ酸が中和するまではこれらの
中和熱によって上昇（図中、縦軸の上方へ）し続ける
か、これらの中和反応が完了すると、放熱などによっ
て、漸次下降していく。In such a series of chemical reactions, the liquid temperature in the titration tank 41 is the same as the above L1 on the horizontal axis of FIG.
As shown by the curve L2 in which the liquid temperature (° C) is displayed on the vertical axis,
According to the reactions represented by the formulas (II), (III), and (IV), does the nitric acid and hydrofluoric acid continue to rise (upward on the vertical axis in the figure) due to the heat of neutralization of these until neutralization? When these neutralization reactions are completed, the temperature gradually decreases due to heat radiation.
【００２７】したがって、図中に示される電気伝導度
（１／Ω）の曲線Ｌ１において、電気伝導度が下降傾向
から上昇傾向に転じる点ａ、この点ａに対応する横軸Ａ
点〔滴定開始時（Ｏｓｅｃ）からＡ点までの滴定時間
（Ａｓｅｃ）を示す〕から遊離硝酸濃度を、また曲線Ｌ
２によって示される液温（℃）が上昇傾向から下降傾向
に転じる点ｂに対応する横軸Ｂ点と前記曲線Ｌ１の上昇
率（上昇傾向）が大きく変わる点Ｃに対応する横軸Ｃ点
とから金属イオンの濃度が求められる。このうち、たと
えば、第２鉄イオン（Ｆｅ3+）の濃度は次のようにして
求められる。前述の如く横軸には常時一定容量でアルカ
リ滴定液４８を滴下したとき滴定時間（ｓｅｃ）が表示
されていて、式（Ｖ）の反応が完了する曲線Ｌ１上の点
Ｃに対応する横軸Ｃ点（Ｃｓｅｃ）と、式（ＩＶ）の中
和反応が完了し、式（Ｖ）の反応が開始する曲線Ｌ２上
の点ｂに対応する横軸Ｂ点（Ｂｓｅｃ）とから、この式
（Ｖ）のみの反応が完了するのに対応して必要とする滴
定時間〔（Ｃ−Ｂ）ｓｅｃ〕が求まるので、これらから
この式（Ｖ）のみの反応を完了するのに必要としたアル
カリ滴定液４８の滴定量と、この滴定量中に溶解し含ま
れているアルカリ量、たとえば滴定に消費されたＮａＯ
Ｈの質量が求まり、この既知のＮａＯＨの質量から前記
式（Ｖ）に基づいて化学当量計算をすることによって、
第２鉄イオン（Ｆｅ3+）の濃度を求めることができるの
である。なお、金属イオンの全量を考えるときには、化
学当量を考えて、全金属イオン量が第２鉄イオン（Ｆｅ
3+）の２００ｇ／ｌに相当する当量、すなわち１０．７
４当量以下になるようにする。Therefore, in the electric conductivity (1 / Ω) curve L1 shown in the figure, a point a at which the electric conductivity changes from a downward tendency to an upward tendency, and the horizontal axis A corresponding to this point a.
From the point [indicating the titration time (Asec) from the start of titration (Osec) to point A], the free nitric acid concentration was measured, and the curve L
A horizontal axis B point corresponding to a point b at which the liquid temperature (° C.) indicated by 2 changes from an upward tendency to a downward trend, and a horizontal axis C point corresponding to a point C at which the rate of increase (upward tendency) of the curve L1 greatly changes. The concentration of metal ions can be obtained from Of these, for example, the concentration of ferric ion (Fe 3+ ) is obtained as follows. As described above, the abscissa indicates the titration time (sec) when the alkali titrant 48 is constantly dropped in a constant volume, and the abscissa corresponds to the point C on the curve L1 where the reaction of the formula (V) is completed. From the point C (Csec) and the point B (Bsec) on the horizontal axis corresponding to the point b on the curve L2 at which the neutralization reaction of the equation (IV) is completed and the reaction of the equation (V) starts, this equation ( The titration time [(C−B) sec] required for completion of the reaction of only V) can be obtained. Therefore, from these, the alkali titration required for completion of the reaction of only this formula (V) The titration amount of the liquid 48 and the amount of alkali contained in the titration amount, for example, NaO consumed for the titration
The mass of H is obtained, and the chemical equivalent is calculated from the mass of this known NaOH based on the above formula (V),
The concentration of ferric ion (Fe 3+ ) can be obtained. When considering the total amount of metal ions, considering the chemical equivalent, the total amount of metal ions is the ferric ion (Fe
3+ ) equivalent to 200 g / l, ie 10.7
It should be 4 equivalents or less.
【００２８】本実施例では、第１酸洗槽１１のみを使用
するときには、金属イオンを含んだ酸洗液は、中継槽２
８および回収槽３７に貯えられるだけで使わない。第２
酸洗槽１２を使用するときは、第１および第２酸洗槽１
１，１２からの金属を含んだ酸洗液を使用することにな
る。したがって酸洗液のバランスを考える必要がある。
一般には、第１酸洗槽１１のみの使用（図１（２））の
場合と比較して、第２酸洗槽１２を使用（図１（１））
の場合が等しいか多いので回収酸が余剰にできることは
ない。第２酸洗槽１２から減少する液は、第２ポンプに
よって中継槽２８へ抜出される液の他に、金属帯１ａに
付随して系外に持出されるものと、第２酸洗槽１２から
蒸発するものとがある。第２酸洗槽１２の温度は、酸洗
に適した５０℃前後に保持される。したがって第１およ
び第２酸洗槽１１，１２から中継槽２８に抜出される量
よりも、回収酸槽３７から第２酸洗槽１２に補給される
量が多くなり、さらに不足分が新しい硝酸、フッ酸およ
び水によって補充される。したがって中継槽２８から回
収酸槽３７までが１系統のみで充分である。In this embodiment, when only the first pickling tank 11 is used, the pickling solution containing metal ions is used in the relay tank 2.
8 and the collection tank 37 only store and do not use. Second
When using the pickling tank 12, the first and second pickling tanks 1
A pickling solution containing metals from 1, 12 will be used. Therefore, it is necessary to consider the balance of the pickling solution.
Generally, the second pickling tank 12 is used (FIG. 1 (1)) as compared with the case of using only the first pickling tank 11 (FIG. 1 (2)).
Since the cases of are equal or large, the recovered acid cannot be surplus. The liquid reduced from the second pickling tank 12 is taken out of the system together with the metal strip 1a in addition to the liquid extracted to the relay tank 28 by the second pump, and the second pickling tank 12 Some evaporate from. The temperature of the second pickling tank 12 is maintained at around 50 ° C., which is suitable for pickling. Therefore, the amount replenished from the recovery pickling tank 37 to the second pickling tank 12 is larger than the amount withdrawn from the first and second pickling tanks 11 and 12 to the relay tank 28. , Supplemented with hydrofluoric acid and water. Therefore, only one system from the relay tank 28 to the recovered acid tank 37 is sufficient.
【００２９】次に第１酸洗槽１１の酸洗液の分析結果に
よって液の抜取りと補給を制御手段１５によって自動的
に行う操作を図６に示すフローチャートを用いて説明す
る。第１酸洗槽１１が使われることを指定して、ステッ
プａ１でスタートする。ステップａ２で分析手段４０か
らの金属イオン濃度が基準値、たとえば２００ｇ／ｌ以
上かどうかが判断される。これが２００ｇ／ｌ以上であ
れば、ステップａ３で一定量、たとえば１ｍ3の酸洗液
が第１ポンプ１６によって中継槽２８に抜出される。ス
テップａ４で抜出された酸洗液に相当する硝酸、たとえ
ば６００ｇ／ｌの濃度の硝酸が１００リットル補給され
る。ステップａ５で分析手段４０からの硝酸濃度が基準
値、たとえば５０ｇ／ｌ以下かどうかが判断される。硝
酸濃度が５０ｇ／ｌ以下のときは、ステップａ６で一定
量の硝酸、たとえば６００ｇ／ｌの濃度の硝酸が１００
リットル補給される。この硝酸の補給は、基準濃度との
差が計算され、それに見合う量が補給されるのが好まし
いが、１０分毎に分析しそれに基づいて補給を行う本装
置の場合は急激な硝酸濃度の変化はないので特別な計算
をせず一定量硝酸が補給される。これは後述の第２酸洗
槽１２に硝酸またはフッ酸を供給するときにも適用され
る。Next, the operation of automatically extracting and replenishing the solution by the control means 15 based on the analysis result of the pickling solution in the first pickling tank 11 will be described with reference to the flowchart shown in FIG. Designating that the first pickling bath 11 is used, the process starts at step a1. At step a2, it is judged whether or not the metal ion concentration from the analyzing means 40 is a reference value, for example, 200 g / l or more. If this is 200 g / l or more, a fixed amount, for example, 1 m 3 of pickling solution is withdrawn by the first pump 16 to the relay tank 28 in step a3. 100 liters of nitric acid corresponding to the pickling solution extracted in step a4, for example, nitric acid having a concentration of 600 g / l is replenished. At step a5, it is judged whether or not the nitric acid concentration from the analyzing means 40 is a reference value, for example, 50 g / l or less. When the nitric acid concentration is 50 g / l or less, a fixed amount of nitric acid, for example, a nitric acid having a concentration of 600 g / l is added in step a6.
It will be replenished in liters. For this replenishment of nitric acid, the difference from the reference concentration is calculated, and it is preferable to replenish in an amount commensurate with the difference, but in the case of this device that analyzes every 10 minutes and replenishes based on this, a rapid change in nitric acid concentration Since it does not exist, a certain amount of nitric acid is supplied without special calculation. This is also applied when supplying nitric acid or hydrofluoric acid to the second pickling tank 12 described later.
【００３０】ステップａ７で水を供給するバルブ１７が
一定時間開く。バルブ１７は、さらに第１酸洗槽１１の
液面によって開閉し、第１酸洗槽１１の液面を基準の液
面にする。In step a7, the valve 17 for supplying water is opened for a certain period of time. The valve 17 is further opened / closed by the liquid level of the first pickling tank 11, so that the liquid level of the first pickling tank 11 becomes the reference liquid level.
【００３１】ステップａ８で１０分が経過したかどうか
が判断され、１０分が経過していれば、ステップａ９に
進み、一連の酸洗処理が終了したかどうかが判断され
る。酸洗処理が終了していなければステップａ２に戻
り、終了していればステップａ１０でエンドとなる。ス
テップａ２で金属イオン濃度が２００ｇ／ｌ未満のとき
は、ステップａ３、ステップａ４をバイパスする。また
ステップａ５で硝酸濃度が５０ｇ／ｌを超えるときは、
ステップａ６をバイパスする。In step a8, it is determined whether 10 minutes have elapsed. If 10 minutes have elapsed, the process proceeds to step a9, and it is determined whether a series of pickling treatments has been completed. If the pickling process is not completed, the process returns to step a2, and if it is completed, the process ends in step a10. When the metal ion concentration is less than 200 g / l in step a2, steps a3 and a4 are bypassed. When the nitric acid concentration exceeds 50 g / l in step a5,
Bypass step a6.
【００３２】前記一連の動作で、金属イオン濃度が２０
０ｇ／ｌ未満で、硝酸濃度が５０ｇ／ｌ以下のときは、
液が抜出されずに硝酸が補給されるので、理論的には、
第１酸洗槽１１の酸洗液が１００リットル増加すること
になるが、この量は第１酸洗槽１１のデットスペースと
して吸収される。また酸洗液が金属帯に付随して系外に
持出され、第１酸洗槽１１の作業温度が約５０℃に保持
されているので、液が蒸発することによる液の減少があ
るので、液が第１酸洗槽１１から溢れることは通常の作
業ではない。これは後述の第２酸洗槽１２についても同
様である。In the above series of operations, the metal ion concentration is 20
When the nitric acid concentration is less than 0 g / l and the nitric acid concentration is 50 g / l or less,
Since nitric acid is replenished without removing the liquid, theoretically,
The amount of the pickling solution in the first pickling tank 11 increases by 100 liters, but this amount is absorbed as a dead space in the first pickling tank 11. Further, since the pickling solution is brought out of the system along with the metal strip and the working temperature of the first pickling tank 11 is maintained at about 50 ° C., the solution is reduced due to evaporation of the solution. It is not a normal operation that the liquid overflows from the first pickling tank 11. This also applies to the second pickling tank 12 described later.
【００３３】次に第２酸洗槽１２の酸洗液の分析結果に
よって液の抜取りと補給を制御手段１５によって自動的
に行う操作を図７に示すフローチャートを用いて説明す
る。第２酸洗槽１２が使われることを指定して、ステッ
プｂ１でスタートする。ステップｂ２で分析手段４０か
らの金属イオン濃度が基準値、たとえば２００ｇ／ｌ以
上かどうかが判断される。これが２００ｇ／ｌ以上であ
れば、ステップｂ３で一定量、たとえば１ｍ3の酸洗液
が第２ポンプ２１によって中継槽２８に抜出される。ス
テップｂ４で回収酸槽３７に回収酸があるかどうかが判
断され、回収酸があれば、ステップｂ５に進み、回収酸
ポンプ２２が稼働し、回収酸供給バルブ２６が開く。バ
ルブ２６は、第２酸洗槽１２の液面によっても開閉し、
第２酸洗槽１２が基準の液面になれば、ポンプ２２が停
止し、バルブ２６が閉じる。回収酸槽３７が空であれ
ば、ステップｂ６に進み、ステップｂ３で抜出された液
に相当する硝酸、たとえば６００ｇ／ｌの硝酸が８０リ
ットルとフッ酸、たとえば１２０ｇ／ｌのフッ酸２０リ
ットルとが補給される。ステップｂ７で分析手段４０か
らのフッ酸の濃度が基準値、たとえば２ｇ／ｌ以下かど
うかが判断される。フッ酸濃度が２ｇ／ｌ以下のとき
は、ステップｂ８で一定量のフッ酸、たとえば１２０ｇ
／ｌのフッ酸が２０リットル供給される。ステップｂ９
で分析手段４０からの硝酸濃度が基準値、たとえば４０
ｇ／ｌ以下かどうかが判断される。硝酸濃度が４０ｇ／
ｌ以下のときは、ステップｂ１０で一定量の硝酸、たと
えば６００ｇ／ｌの硝酸が８０リットル補給される。ス
テップｂ１１で水を供給するバルブ２３が一定時間開
く。バルブ２３は、さらに第２酸洗槽１２の液面によっ
て開閉し、第２酸洗槽１２の液面を基準の液面にする。
ステップｂ１２で１０分が経過されたかどうかが判断さ
れ、１０分が経過していれば、ステップｂ１３に進み、
一連の酸洗処理が終了したかどうかが判断される。酸洗
処理が終了していなければステップｂ２に戻り、終了し
ていればステップｂ１４でエンドとなる。ステップｂ２
で金属イオン濃度が２００ｇ／ｌ未満のときは、ステッ
プｂ３〜ステップｂ６をバイパスする。またステップｂ
４でフッ酸濃度２ｇ／ｌを超えるときはステップｂ８
を、ステップｂ９で硝酸濃度が４０ｇ／ｌを超えるとき
はステップｂ１０をそれぞれバイパスする。Next, the operation of automatically extracting and replenishing the pickling solution by the control means 15 based on the analysis result of the pickling solution in the second pickling tank 12 will be described with reference to the flowchart shown in FIG. Designating that the second pickling tank 12 is used, the process starts at step b1. In step b2, it is judged whether the metal ion concentration from the analyzing means 40 is a reference value, for example, 200 g / l or more. If this is 200 g / l or more, a fixed amount, for example, 1 m 3 of pickling solution is withdrawn to the relay tank 28 by the second pump 21 in step b3. In step b4, it is judged whether or not there is recovered acid in the recovered acid tank 37. If there is recovered acid, the process proceeds to step b5, the recovered acid pump 22 operates, and the recovered acid supply valve 26 opens. The valve 26 also opens and closes depending on the liquid level of the second pickling tank 12,
When the second pickling tank 12 reaches the standard liquid level, the pump 22 is stopped and the valve 26 is closed. If the recovery acid tank 37 is empty, the process proceeds to step b6, and 80 liters of nitric acid corresponding to the liquid extracted in step b3, for example, 600 g / l nitric acid and hydrofluoric acid, for example, 120 g / l hydrofluoric acid 20 liters. And are replenished. At step b7, it is judged whether the concentration of hydrofluoric acid from the analyzing means 40 is a reference value, for example, 2 g / l or less. When the concentration of hydrofluoric acid is 2 g / l or less, a constant amount of hydrofluoric acid, for example 120 g, is added in step b8.
20 liters of hydrofluoric acid / liter are supplied. Step b9
Therefore, the nitric acid concentration from the analyzing means 40 is a reference value, for example, 40
It is determined whether it is less than or equal to g / l. Nitric acid concentration is 40g /
If it is 1 or less, 80 liters of a fixed amount of nitric acid, for example, 600 g / l of nitric acid is replenished in step b10. In step b11, the valve 23 that supplies water is opened for a certain period of time. The valve 23 is further opened and closed by the liquid level of the second pickling tank 12, so that the liquid level of the second pickling tank 12 becomes the reference liquid level.
In step b12, it is determined whether 10 minutes have passed, and if 10 minutes have passed, the process proceeds to step b13.
It is determined whether or not a series of pickling treatments have been completed. If the pickling process is not completed, the process returns to step b2, and if it is completed, the process ends in step b14. Step b2
When the metal ion concentration is less than 200 g / l, steps b3 to b6 are bypassed. Also step b
When the hydrofluoric acid concentration exceeds 2 g / l in step 4, step b8
When the nitric acid concentration exceeds 40 g / l in step b9, step b10 is bypassed.
【００３４】[0034]
【発明の効果】以上のように本発明によれば、金属帯の
脱スケールのために硝酸と電極とによって酸洗する第１
酸洗槽と、硝酸とフッ酸との混酸によって酸洗する第２
酸洗槽とを備えた酸洗装置において、各酸洗槽から抜取
られた金属イオンを含んだ酸洗液を、イオン交換膜によ
って金属イオンを除去して酸成分を回収し、回収した回
収酸を第２酸洗槽に返すことによって、酸を有効に使用
でき、酸洗液の廃棄に必要な中和処理を省略できる。ま
たイオン交換膜から構成される高価な酸回収手段を酸洗
系統が２系統あるにもかかわらず１系統で行うことがで
きる。As described above, according to the present invention, first pickling with nitric acid and an electrode is performed for descaling of the metal strip.
Pickling tank and pickling with a mixed acid of nitric acid and hydrofluoric acid
In a pickling apparatus equipped with a pickling tank, a pickling solution containing metal ions extracted from each pickling tank is used to remove metal ions by an ion exchange membrane to recover an acid component, and the recovered acid is recovered. Is returned to the second pickling tank, the acid can be effectively used, and the neutralization treatment necessary for discarding the pickling solution can be omitted. Further, the expensive acid recovery means composed of the ion exchange membrane can be performed by one system although there are two systems for pickling.
【図面の簡単な説明】[Brief description of drawings]
【図１】本発明の一実施例の第１酸洗槽１１と第２酸洗
槽１２と金属帯１との関係を示す図である。FIG. 1 is a diagram showing a relationship between a first pickling tank 11, a second pickling tank 12, and a metal strip 1 according to an embodiment of the present invention.
【図２】酸洗液の流れを示す系統図である。FIG. 2 is a system diagram showing a flow of a pickling solution.
【図３】酸回収手段３０の作用を説明する説明図であ
る。FIG. 3 is an explanatory diagram illustrating an operation of the acid recovery means 30.
【図４】第２酸洗槽１２と分析手段４０との関係を説明
する説明図である。FIG. 4 is an explanatory diagram illustrating a relationship between a second pickling tank 12 and an analyzing unit 40.
【図５】酸洗液をアルカリ滴定したときの電気伝導度と
液温の変化を示すグラフである。FIG. 5 is a graph showing changes in electric conductivity and solution temperature when the pickling solution is titrated with alkali.
【図６】制御手段１５によって第１酸洗槽１１の液の抜
取りと補給との動作を説明するフローチャートである。FIG. 6 is a flowchart for explaining the operation of draining and replenishing the liquid in the first pickling tank 11 by the control means 15.
【図７】制御手段１５によって第２酸洗槽１２の液の抜
取りと補給との動作を説明するフローチャートである。FIG. 7 is a flowchart for explaining the operation of draining and replenishing the liquid in the second pickling tank 12 by the control means 15.
１ａ，１ｂ 金属帯 ３，４ 可動浸漬ローラ １１ 第１酸洗槽 １２ 第２酸洗槽 １３ 電極 １５ 制御手段 １６ 第１ポンプ ２１ 第２ポンプ ２２ 回収酸ポンプ ２８ 中継槽 ３０ 酸洗手段 ３１ 隔壁 ３３ 陰イオン交換膜 ３７ 回収酸槽 ３８ 廃酸処理装置 ４０ 分析手段 1a, 1b Metal strip 3,4 Movable dipping roller 11 First pickling tank 12 Second pickling tank 13 Electrode 15 Control means 16 First pump 21 Second pump 22 Recovered acid pump 28 Relay tank 30 Pickling means 31 Partition wall 33 Anion exchange membrane 37 Recovery acid tank 38 Waste acid treatment device 40 Analytical means
Claims (4)
槽と、硝酸とフッ酸との混酸によって酸洗する第２酸洗
槽とを備えた酸洗装置において、 第１および第２酸洗槽の酸洗液を槽外に導き、陰イオン
交換膜から成る酸回収手段によって金属イオンを除去し
て、硝酸およびフッ酸を回収し、この回収した回収酸を
第２酸洗槽に返すことを特徴とする金属帯の酸洗装置に
おける酸回収方法。1. A pickling apparatus comprising: a first pickling tank for pickling a metal strip with nitric acid; and a second pickling tank for pickling a mixed acid of nitric acid and hydrofluoric acid. The pickling solution in the pickling tank is guided to the outside of the tank, the metal ions are removed by the acid collecting means consisting of an anion exchange membrane, nitric acid and hydrofluoric acid are collected, and the collected recovered acid is transferred to the second pickling tank. A method for recovering an acid in a pickling device for a metal strip, which is characterized by returning the acid.
酸濃度、フッ素イオン濃度および金属イオン濃度を測定
し、これらが定められた濃度範囲になるように、第１お
よび第２酸洗槽の酸洗液を槽外に導き、第１酸洗槽に硝
酸および水を、第２酸洗槽に硝酸、水、フッ酸および前
記回収酸を補給することを特徴とする請求項１記載の金
属帯の酸洗装置における酸回収方法。2. The acid concentration, the fluoride ion concentration and the metal ion concentration of the pickling solution in the first and second pickling tanks are measured, and the first and second concentrations are set so that these are within a predetermined concentration range. 2. The pickling solution in the second pickling tank is introduced to the outside of the tank, and nitric acid and water are supplied to the first pickling tank, and nitric acid, water, hydrofluoric acid and the recovered acid are supplied to the second pickling tank. Item 2. A method for recovering an acid in a pickling apparatus for a metal strip according to Item 1.
を特徴とする請求項１または請求項２に記載のステンレ
ス鋼帯の酸洗装置における回収方法。3. The method for recovering a stainless steel strip in a pickling apparatus according to claim 1, wherein the metal strip is a stainless steel strip.
その電極間を連続通板する金属帯を浸漬する第１酸洗槽
と、 硝酸とフッ酸を貯留する酸洗槽内に、連続通板する金属
帯を浸漬する第２酸洗槽と、 前記第１酸洗槽または第２酸洗槽内の酸洗液の一部を抜
出して、各酸洗液の酸濃度、フッ素イオン濃度および金
属イオン濃度を分析する分析手段と、 酸洗液を貯留する中継槽と、 前記第１酸洗槽の酸洗液を前記中継槽に送る第１ポンプ
と、 前記第２酸洗槽の酸洗液を前記中継槽に送る第２ポンプ
と、 前記中継槽の酸洗液を第３ポンプを介して受入れ、酸洗
液中の金属イオンを除去して酸を回収する陰イオン交換
膜から構成される酸回収手段と、 回収された回収酸を貯留する回収酸槽と、 硝酸、および水を第１酸洗槽に供給する第１供給手段
と、 硝酸、フッ酸、水および回収酸槽の回収酸を第２酸洗槽
に供給する第２供給手段と、 前記分析手段からの第１酸洗槽の酸洗液の各成分濃度が
定められた濃度範囲になるように、第１ポンプおよび第
１供給手段を制御し、第２酸洗槽の各成分濃度が定めら
れた濃度範囲になるように第２ポンプおよび第２供給手
段を制御する制御手段とから成ることを特徴とする金属
帯の酸洗装置。4. An electrode is provided in a pickling tank for storing nitric acid,
A first pickling tank for immersing a metal strip that continuously passes between the electrodes; and a second pickling tank for immersing a continuous metal strip in a pickling bath that stores nitric acid and hydrofluoric acid, A part of the pickling solution in the first pickling tank or the second pickling tank is extracted to analyze the acid concentration, fluorine ion concentration and metal ion concentration of each pickling solution, and the pickling solution is stored. Relay tank, a first pump that sends the pickling solution from the first pickling tank to the relay tank, a second pump that sends the pickling solution from the second pickling tank to the relay tank, and the relay tank Acid pickling solution from the third pump, the acid collecting means including an anion exchange membrane for removing the metal ions in the pickling solution to collect the acid, and the recovery for storing the recovered acid. An acid tank, first supply means for supplying nitric acid and water to the first pickling tank, nitric acid, hydrofluoric acid, water and recovered acid in the recovered acid tank The second supply means for supplying to the pickling tank, and the first pump and the first supplying means so that the concentration of each component of the pickling solution in the first pickling tank from the analyzing means falls within a predetermined concentration range. A picking device for a metal strip, comprising: a control means for controlling and controlling the second pump and the second supplying means so that the concentration of each component in the second pickling tank falls within a predetermined concentration range.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31211493A JP3339735B2 (en) | 1993-12-13 | 1993-12-13 | Method and apparatus for recovering acid in pickling apparatus for metal strip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31211493A JP3339735B2 (en) | 1993-12-13 | 1993-12-13 | Method and apparatus for recovering acid in pickling apparatus for metal strip |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07166383A true JPH07166383A (en) | 1995-06-27 |
| JP3339735B2 JP3339735B2 (en) | 2002-10-28 |
Family
ID=18025415
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31211493A Expired - Fee Related JP3339735B2 (en) | 1993-12-13 | 1993-12-13 | Method and apparatus for recovering acid in pickling apparatus for metal strip |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3339735B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007530282A (en) * | 2004-03-25 | 2007-11-01 | ユジンヌ・エ・アルツ・フランス | Manufacturing method of austenitic stainless steel strip with matte finish |
| JP2013534179A (en) * | 2010-08-02 | 2013-09-02 | エヌシーエイチ コーポレイション | Parts washer using aqueous detergent |
| CN112023520A (en) * | 2020-09-03 | 2020-12-04 | 浙江明铖金属科技有限公司 | High-efficiency pickling equipment and technology for metal surface |
| CN112064048A (en) * | 2020-09-03 | 2020-12-11 | 浙江明铖金属科技有限公司 | High-precision cold heading finished wire processing device and process |
| CN113755852A (en) * | 2021-09-13 | 2021-12-07 | 浙江金洲管道科技股份有限公司 | Treatment system and method for reducing acid consumption and reducing emission of red mud in steel acid pickling and rust removing process |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1026906B1 (en) * | 2018-12-20 | 2020-07-22 | Aperam Stainless Belgium | Method for producing stainless steel sheet finished in at least three different ways |
| BE1026907B1 (en) * | 2018-12-20 | 2020-07-22 | Aperam Stainless Belgium | Method for producing stainless steel sheet finished in at least three different ways |
-
1993
- 1993-12-13 JP JP31211493A patent/JP3339735B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007530282A (en) * | 2004-03-25 | 2007-11-01 | ユジンヌ・エ・アルツ・フランス | Manufacturing method of austenitic stainless steel strip with matte finish |
| JP2013534179A (en) * | 2010-08-02 | 2013-09-02 | エヌシーエイチ コーポレイション | Parts washer using aqueous detergent |
| CN112023520A (en) * | 2020-09-03 | 2020-12-04 | 浙江明铖金属科技有限公司 | High-efficiency pickling equipment and technology for metal surface |
| CN112064048A (en) * | 2020-09-03 | 2020-12-11 | 浙江明铖金属科技有限公司 | High-precision cold heading finished wire processing device and process |
| CN113755852A (en) * | 2021-09-13 | 2021-12-07 | 浙江金洲管道科技股份有限公司 | Treatment system and method for reducing acid consumption and reducing emission of red mud in steel acid pickling and rust removing process |
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| Publication number | Publication date |
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| JP3339735B2 (en) | 2002-10-28 |
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