JP5262127B2 - How to recover, regenerate and supply acid solutions in steel strip pickling equipment, annealing / pickling equipment and pickling tanks - Google Patents

How to recover, regenerate and supply acid solutions in steel strip pickling equipment, annealing / pickling equipment and pickling tanks Download PDF

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JP5262127B2
JP5262127B2 JP2008012127A JP2008012127A JP5262127B2 JP 5262127 B2 JP5262127 B2 JP 5262127B2 JP 2008012127 A JP2008012127 A JP 2008012127A JP 2008012127 A JP2008012127 A JP 2008012127A JP 5262127 B2 JP5262127 B2 JP 5262127B2
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acid
sulfuric acid
pickling
filter
exchange resin
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JP2009173980A (en
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正剛 菊山
泰博 和田
一也 竹村
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JFE Steel Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of clogging in a filter 4 in annealing and pickling equipment, an acid-pickling tank, and pickling equipment for a steel strip S used in a recovery, regeneration, and supply method of an acid solution, which has a circulation system 60 that includes the filter 4 and an ion-exchange resin 5 in series in a flowing direction of a recovered acid solution and is used for executing recovery-regeneration of an acid solution from an acid-pickling tank 1 and supply of an acid solution to the acid-pickling tank 1. <P>SOLUTION: In order to prevent the occurrence of clogging in the filter 4, a hydrofluoric acid is supplied from a hydrofluoric-acid tank 9 to the filter 4. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

本発明は、鋼帯の酸洗設備、焼鈍・酸洗設備および酸洗槽での、酸液の回収・再生・供給方法に関する。   The present invention relates to a method for recovering, regenerating and supplying an acid solution in a steel strip pickling facility, an annealing / pickling facility, and a pickling tank.

例えば、図4に示すような、ステンレス鋼帯の焼鈍・酸洗設備は、鋼帯Sの搬送方向にみて焼鈍炉の下流側に酸洗設備を備えている。 For example, a stainless steel strip annealing / pickling facility as shown in FIG. 4 includes a pickling facility on the downstream side of the annealing furnace as viewed in the conveying direction of the steel strip S.

この酸洗設備は、鋼帯表層の酸化物(スケール)を除去することを目的として、通常2〜3槽のタンクが直列に設置されている。また、図5に示すように、酸洗槽1の下部に設置された循環タンク2を介して酸液を循環させ、酸液の回収と供給を行いながら鋼帯Sの酸洗を行っている。酸液も製造条件に応じて各種のものが用いられているが、最近では前段部分で硫酸が用いられることが多い。   In this pickling facility, tanks of 2 to 3 tanks are usually installed in series for the purpose of removing oxides (scale) on the surface of the steel strip. Moreover, as shown in FIG. 5, the acid solution is circulated through the circulation tank 2 installed in the lower part of the pickling tank 1, and the steel strip S is pickled while collecting and supplying the acid solution. . Various types of acid solutions are used depending on the production conditions, but recently, sulfuric acid is often used in the former part.

ここで、ステンレス鋼帯の硫酸酸洗のメカニズムについて以下に説明する。
鋼帯母材 Fe + H2 SO4 → FeSO4 (溶解)+ H2 ↑
Cr + H2 SO4 → CrSO4 (溶解)+ H2 ↑
酸化スケール Fe3 04 → Fe3 04 ↓(沈殿)
Cr2 03 → Cr2 03 ↓(沈殿)
上記したとおり、硫酸中では酸化物(スケール)は不溶性のため沈殿し、硫酸酸洗槽1の底や、硫酸酸洗槽1からの硫酸の回収・再生と、同硫酸酸洗槽1への酸液の供給と、を司る硫酸の循環系の途中に設置された、後出の図6中に示す、硫酸循環タンク2や回収酸タンク3の底などに堆積する。
Here, the sulfuric acid pickling mechanism of the stainless steel strip will be described below.
Steel strip base material Fe + H2 SO4 → FeSO4 (melting) + H2 ↑
Cr + H2 SO4 → CrSO4 (dissolved) + H2 ↑
Oxidation scale Fe3 04 → Fe3 04 ↓ (precipitation)
Cr2 03 → Cr2 03 ↓ (precipitation)
As described above, the oxide (scale) is precipitated in sulfuric acid because it is insoluble, and the bottom of the sulfuric acid pickling tank 1 and the recovery and regeneration of sulfuric acid from the sulfuric acid pickling tank 1 and the return to the sulfuric acid pickling tank 1 The acid solution is deposited on the bottom of the sulfuric acid circulation tank 2 and the recovered acid tank 3 shown in FIG. 6, which is installed in the middle of the sulfuric acid circulation system that controls the supply of the acid solution.

また、鋼帯母材成分の金属塩(硫酸鉄(FeSO4 )、硫酸クロム(CrSO4 ))もある程度までは硫酸中に溶解しているが、溶解限度を超えると析出し、酸化物(スケール)と同様に酸洗槽1の底や回収酸タンク3の底に堆積するようになる。   In addition, metal salts (iron sulfate (FeSO4), chromium sulfate (CrSO4)) of the steel strip base material are also dissolved in sulfuric acid to a certain extent, but when they exceed the solubility limit, they precipitate and become oxide (scale). Similarly, it accumulates on the bottom of the pickling tank 1 and the bottom of the recovered acid tank 3.

これら酸化物(スケール)と金属塩の堆積物を併せ、一般に、硫酸スラッジと呼ぶ。   These oxide (scale) and metal salt deposits are generally referred to as sulfuric acid sludge.

ステンレス鋼帯の硫酸酸洗に伴って、硫酸スラッジの堆積レベルが鋼帯Sの通過する領域にまで達すると、鋼帯Sがスラッジと接触して鋼帯Sの表面にスリ疵などが発生する。そのため、従来は、定期的にステンレス鋼帯の焼鈍・酸洗の操業を一時停止し、清掃、すなわち、硫酸スラッジの除去作業を行っていた(以下、定期清掃)。   When the level of sulfuric acid sludge reaches the region where the steel strip S passes along with the sulfuric acid pickling of the stainless steel strip, the steel strip S comes into contact with the sludge and the surface of the steel strip S is generated. . For this reason, conventionally, operations of annealing and pickling of stainless steel strips have been temporarily stopped, and cleaning, that is, removal of sulfuric acid sludge has been performed (hereinafter, periodic cleaning).

硫酸スラッジの発生量は、ステンレス鋼帯の焼鈍・酸洗量に比例して多くなる。従って、ステンレス鋼帯の焼鈍・酸洗における生産性の向上を図ろうとすると、必然的に定期清掃の頻度が増すことになる。   The amount of sulfuric sludge generated increases in proportion to the annealing and pickling amount of the stainless steel strip. Therefore, if it is intended to improve productivity in annealing and pickling of stainless steel strip, the frequency of periodic cleaning will inevitably increase.

このため、ステンレス鋼帯の焼鈍・酸洗における生産性を向上させようとしても、定期清掃の間、ステンレス鋼帯の焼鈍・酸洗の操業を停止せざるを得ないことが障害となって、十分に生産性を向上できなかった。   For this reason, even if trying to improve the productivity in annealing and pickling of stainless steel strips, it becomes an obstacle that the operation of annealing and pickling stainless steel strips must be stopped during regular cleaning, Productivity could not be improved sufficiently.

また、ステンレス鋼帯に限らず、炭素鋼帯も含め、鋼帯の酸洗に際しては、製造コストの面から、酸液を効果的に回収・再生し、再度供給できるようにすることが求められる。   Moreover, when pickling steel strips including not only stainless steel strips but also carbon steel strips, it is required from the standpoint of manufacturing costs that the acid solution be effectively recovered and regenerated and supplied again. .

従来から、ステンレス鋼帯の硫酸酸洗における硫酸の回収方法としては、イオン交換膜を利用して、硫酸を選択的に拡散透析させて回収する方法が知られている。   2. Description of the Related Art Conventionally, as a method for recovering sulfuric acid in sulfuric acid pickling of a stainless steel strip, a method of recovering sulfuric acid by selective diffusion dialysis using an ion exchange membrane is known.

その他、硝弗酸酸洗における硝弗酸の回収・再生方法として、金属イオンを含有する回収した硝弗酸を、まずpH調整し、しかるのち、イオン交換樹脂を通して、回収・再生する方法なども知られている。   In addition, as a method of recovering and regenerating nitric hydrofluoric acid in nitric hydrofluoric acid washing, there is also a method in which the recovered nitric hydrofluoric acid containing metal ions is first adjusted in pH and then recovered and regenerated through an ion exchange resin. Are known.

ところが、イオン交換膜を利用して、硫酸を選択的に拡散透析させて回収する方法では、処理能力が小さい問題があり、金属イオンを含有する回収した硝弗酸を、pH調整し、しかるのち、イオン交換樹脂を通して、回収・再生する方法では、短時間のうちにイオン交換樹脂が機能しなくなる問題があった。   However, the method of selectively recovering sulfuric acid by diffusion dialysis using an ion exchange membrane has a problem that the processing capacity is small, and the pH of the recovered nitric hydrofluoric acid containing metal ions is adjusted accordingly. In the method of collecting and regenerating through the ion exchange resin, there is a problem that the ion exchange resin does not function within a short time.

このため、発明者らは、先に、特許文献1にて、硫酸酸洗槽からの酸液の回収・再生と、同酸洗槽への酸液の供給と、を司る循環系を有する、鋼帯の酸洗設備、焼鈍・酸洗設備および酸洗槽において、前記した循環系が、回収した酸液の流れる方向に直列に、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できる、ろ布方式のろ過器と、イオン交換樹脂とをそなえるようにすることを提案した。   For this reason, the inventors previously have a circulation system that manages the recovery and regeneration of the acid solution from the sulfuric acid pickling tank and the supply of the acid solution to the acid pickling tank in Patent Document 1, In the steel strip pickling equipment, annealing / pickling equipment and pickling tank, the above-mentioned circulation system is in series with the direction of flow of the collected acid solution, and the maximum value of the grain size in one grain is 1.0 μm. It was proposed to have a filter cloth type filter capable of removing the above solid particles and an ion exchange resin.

図6に、特許文献1に従う酸洗設備を模式的に示す。図中、番号3は回収酸タンク、4はろ布方式のろ過器、5はイオン交換樹脂、6は供給酸タンクであり、これらで硫酸の循環系60を構成している。なお、7は廃酸タンク、また、8は硝弗酸酸洗槽、図中の線は配管である。   In FIG. 6, the pickling equipment according to patent document 1 is shown typically. In the figure, reference numeral 3 is a recovered acid tank, 4 is a filter cloth filter, 5 is an ion exchange resin, and 6 is a supply acid tank, which constitute a sulfuric acid circulation system 60. In addition, 7 is a waste acid tank, 8 is a nitric hydrofluoric acid pickling tank, and the line in a figure is piping.

回収酸タンク3、ろ布方式のろ過器4、イオン交換樹脂5、供給酸タンク6を含む硫酸の循環系60に、図示しないポンプにて硫酸を循環させるようにしている。   Sulfuric acid is circulated by a pump (not shown) in a sulfuric acid circulation system 60 including the recovered acid tank 3, the filter cloth type filter 4, the ion exchange resin 5, and the supply acid tank 6.

この特許文献1の特徴は、従来の砂ろ過器、中空糸膜のような清澄ろ過装置や沈降槽あるいはフィルタプレスなどのろ過器に替えて、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できる、ろ布方式のろ過器4をそなえるようにしたことで、まず硫酸酸洗の際に発生する大量かつ微細なスケールを酸液から除去し、その上で、イオン交換樹脂5による酸液の再生ができるようにしたところにある。
特開2005−105364号公報
The feature of this patent document 1 is that the maximum value of the particle size in one grain is 1 instead of a conventional sand filter, a clarification filtration device such as a hollow fiber membrane, a filter such as a sedimentation tank or a filter press. By providing a filter cloth type filter 4 capable of removing solid particles of .mu.m or more, first, a large amount of fine scale generated during sulfuric acid pickling is removed from the acid solution. The acid solution can be regenerated by the ion exchange resin 5.
JP 2005-105364 A

しかしながら、特許文献1の方法を、実際にステンレス鋼帯の焼鈍・酸洗の操業に供していくうちに、ろ過器4が目詰まりを起こす場合があることがわかってきた。 However, it has been found that the filter 4 may become clogged while the method of Patent Document 1 is actually used for the operation of annealing and pickling of a stainless steel strip.

このため、通常、ろ過器4からイオン交換樹脂5の方向に回収した酸液を流し、再生を行うのとは逆に、イオン交換樹脂5にて再生したのちの酸液をイオン交換樹脂5からろ過器4の方向に向かって流す、いわゆる逆洗を行って、目詰まりの原因となっている金属やその酸化物あるいは塩などを溶解して除去する、という方法で対応していた。   For this reason, the acid solution recovered from the ion exchange resin 5 is usually removed from the ion exchange resin 5, contrary to the case where the acid solution recovered from the filter 4 in the direction of the ion exchange resin 5 is flowed and regenerated. This was dealt with by performing so-called backwashing, which flows in the direction of the filter 4, to dissolve and remove the clogging metal, oxide or salt thereof.

しかしながら、回収した酸液の中には、さまざまな微量元素が存在し、これらが原因となって起こる目詰まりを、逆洗によってもなお防止できない場合があることが、問題として新たに浮かび上がってきたのである。   However, there is a new problem that the collected acid solution contains various trace elements, and clogging caused by these elements may not be prevented even by backwashing. It was.

本発明は、従来技術のかような問題を解決するべくなされたものであり、酸洗槽からの酸液の回収・再生と、同酸洗槽への酸液の供給と、を司る循環系を有する、鋼帯の酸洗設備、焼鈍・酸洗設備および酸洗槽であって、しかも、前記した循環系が、回収した酸液の流れる方向に直列に、ろ過器とイオン交換樹脂とをそなえたものである、前記した、鋼帯の酸洗設備、焼鈍・酸洗設備および酸洗槽での、酸液の回収・再生・供給方法において、前記した、ろ過器に目詰まりが起こるのを防止することを目的とする。   The present invention has been made to solve such problems as in the prior art, and has a circulation system that manages the recovery and regeneration of the acid solution from the pickling tank and the supply of the acid solution to the pickling tank. The steel strip pickling equipment, annealing / pickling equipment, and pickling tank, wherein the circulating system includes a filter and an ion exchange resin in series in the direction in which the collected acid solution flows. In the above-described method for recovering, regenerating and supplying the acid solution in the steel strip pickling equipment, annealing / pickling equipment and pickling tank, the filter is clogged. The purpose is to prevent.

すなわち、本発明は以下の通りである。
(1)硫酸酸洗槽と硝弗酸酸洗槽を被処理ステンレス鋼帯の搬送方向に直列に並べ、
前記硫酸酸洗槽は、前記硫酸酸洗槽からの酸液の回収・再生・供給を司る硫酸の循環系を有し、
該循環系は、回収した酸液の流れる方向に直列に、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できるろ過器と、イオン交換樹脂とをそなえたステンレス鋼帯の酸洗設備において、
前記ろ過器に弗酸を供給するようにした
ことを特徴とするステンレス鋼帯の酸洗設備。
(2)(1)のステンレス鋼帯の酸洗設備であって、
前記硫酸酸洗槽に加え、前記硝弗酸酸洗槽も、前記硝弗酸酸洗槽からの酸液の回収・再生・供給を司る硝弗酸の循環系を有する
ことを特徴とするステンレス鋼帯の酸洗設備。
(3)酸洗槽を被処理鋼帯の搬送方向に直列に並べ、
前記酸洗槽は、前記酸洗槽からの酸液の回収・再生・供給を司る酸液の循環系を有し、
該循環系は、回収した酸液の流れる方向に直列に、ろ過器とイオン交換樹脂とをそなえた鋼帯の酸洗設備において、
前記ろ過器に弗酸を供給するようにした
ことを特徴とする鋼帯の酸洗設備。
(4)(1)〜(3)のいずれかの酸洗設備の搬送方向上流側に、さらに焼鈍炉を備えた
ことを特徴とする鋼帯の焼鈍・酸洗設備。
(5)硫酸酸洗槽から回収した硫酸を、ろ過器に導いて、前記回収した硫酸中に含まれる、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去したのち、
イオン交換樹脂に導いて、前記回収した硫酸中の硫酸イオンをイオン交換樹脂に吸着させ、
ついで、硫酸イオンが吸着したイオン交換樹脂に、水を供給して、前記イオン交換樹脂に吸着した硫酸イオンを、水に溶解させて、前記回収した硫酸を再生し、
さらに、再生した硫酸を、新しい硫酸と一緒に前記硫酸酸洗槽に供給する、
硫酸酸洗槽での、硫酸の回収・再生・供給方法において、
前記ろ過器に弗酸を供給するようにした
ことを特徴とする硫酸酸洗槽での、硫酸の回収・再生・供給方法。
(6)硫酸酸洗槽から回収した硫酸を、ろ過器に導いて、前記回収した硫酸中に含まれる、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去したのち、
イオン交換樹脂に導いて、前記回収した硫酸中の硫酸イオンをイオン交換樹脂に吸着させ、
ついで、硫酸イオンが吸着したイオン交換樹脂に、水を供給して、前記イオン交換樹脂に吸着した硫酸イオンを、水に溶解させて、前記回収した硫酸を再生し、
さらに、再生した硫酸を、新しい硫酸と一緒に前記硫酸酸洗槽に供給するようにするとともに、
硝弗酸酸洗槽から回収した硝弗酸を、ろ過したのち、
イオン交換樹脂に導いて、前記回収した硝弗酸中の金属イオンをイオン交換樹脂に吸着させることにより、前記回収した硝弗酸を再生し、
さらに、再生した硝弗酸を、新しい硝弗酸と一緒に前記硝弗酸酸洗槽に供給する、
硫酸酸洗槽および硝弗酸酸洗槽での、酸液の回収・再生・供給方法において、
前記ろ過器に弗酸を供給するようにした
ことを特徴とする硫酸酸洗槽での、硫酸の回収・再生・供給方法。
(7)酸洗槽から回収した酸液を、ろ過器に導いて、前記回収した酸液中に含まれる、一つの粒内で粒径の最大値が1.0μm以上の固形粒子を除去したのち、
イオン交換樹脂に導いて、前記回収した酸液中の酸イオンをイオン交換樹脂に吸着させ、
ついで、酸イオンが吸着したイオン交換樹脂に、水を供給して、前記イオン交換樹脂に吸着した酸イオンを、水に溶解させて、前記回収した酸液を再生し、
さらに、再生した酸液を、新しい酸液と一緒に酸洗槽に供給する、
酸洗槽での、酸液の回収・再生・供給方法において、
前記ろ過器に弗酸を供給するようにした
ことを特徴とする酸洗槽での、酸液の回収・再生・供給方法。
That is, the present invention is as follows.
(1) A sulfuric acid pickling tank and a nitric hydrofluoric acid pickling tank are arranged in series in the conveying direction of the stainless steel strip to be treated.
The sulfuric acid pickling tank has a sulfuric acid circulation system that manages recovery, regeneration, and supply of the acid solution from the sulfuric acid pickling tank,
The circulatory system is a stainless steel provided with a filter capable of removing solid particles having a maximum particle size of 1.0 μm or more in one particle in series with the flow direction of the collected acid solution, and an ion exchange resin. In pickling equipment for steel strips,
A pickling facility for a stainless steel strip, characterized in that hydrofluoric acid is supplied to the filter.
(2) The pickling equipment for the stainless steel strip of (1),
In addition to the sulfuric acid pickling tank, the nitric hydrofluoric acid washing tank also has a nitric hydrofluoric acid circulation system that manages recovery, regeneration, and supply of the acid solution from the nitric hydrofluoric acid washing tank. Steel strip pickling equipment.
(3) The pickling tanks are arranged in series in the conveying direction of the steel strip to be treated,
The pickling tank has an acid solution circulation system that manages recovery, regeneration, and supply of the acid solution from the pickling tank,
The circulation system is a steel strip pickling facility provided with a filter and an ion exchange resin in series with the direction in which the collected acid solution flows.
A steel strip pickling facility characterized in that hydrofluoric acid is supplied to the filter.
(4) An annealing / pickling facility for steel strip, further comprising an annealing furnace on the upstream side in the transport direction of the pickling facility according to any one of (1) to (3).
(5) The sulfuric acid recovered from the sulfuric acid washing tank was guided to a filter to remove solid particles having a maximum particle size of 1.0 μm or more contained in the recovered sulfuric acid. Later
Lead to an ion exchange resin, adsorb the sulfate ions in the recovered sulfuric acid to the ion exchange resin,
Next, water is supplied to the ion exchange resin on which sulfate ions are adsorbed, and the sulfate ions adsorbed on the ion exchange resin are dissolved in water to regenerate the recovered sulfuric acid,
Furthermore, the regenerated sulfuric acid is supplied to the sulfuric acid washing tank together with fresh sulfuric acid.
In the method of sulfuric acid recovery / regeneration / supply in the sulfuric acid pickling tank,
A method for recovering, regenerating and supplying sulfuric acid in a sulfuric acid washing tank, wherein hydrofluoric acid is supplied to the filter.
(6) The sulfuric acid recovered from the sulfuric acid washing tank was guided to a filter to remove solid particles having a maximum particle size of 1.0 μm or more contained in the recovered sulfuric acid. Later
Lead to an ion exchange resin, adsorb the sulfate ions in the recovered sulfuric acid to the ion exchange resin,
Next, water is supplied to the ion exchange resin on which sulfate ions are adsorbed, and the sulfate ions adsorbed on the ion exchange resin are dissolved in water to regenerate the recovered sulfuric acid,
Furthermore, the regenerated sulfuric acid is supplied to the sulfuric acid washing tank together with fresh sulfuric acid,
After filtering the nitric hydrofluoric acid recovered from the nitric hydrofluoric acid washing tank,
Reducing the recovered nitrohydrofluoric acid by guiding it to the ion exchange resin and adsorbing the metal ions in the recovered nitrohydrofluoric acid to the ion exchange resin,
Furthermore, the regenerated nitric hydrofluoric acid is supplied to the nitric hydrofluoric acid washing tank together with new nitric hydrofluoric acid.
In the method for collecting, regenerating and supplying the acid solution in the sulfuric acid pickling tank and the nitric hydrofluoric acid pickling tank,
A method for recovering, regenerating and supplying sulfuric acid in a sulfuric acid washing tank, wherein hydrofluoric acid is supplied to the filter.
(7) The acid solution recovered from the pickling tank was guided to a filter, and solid particles having a maximum particle size of 1.0 μm or more contained in one of the particles contained in the recovered acid solution were removed. Later
Lead to ion exchange resin, adsorb acid ions in the collected acid solution to ion exchange resin,
Next, water is supplied to the ion exchange resin on which the acid ions are adsorbed, and the acid ions adsorbed on the ion exchange resin are dissolved in water to regenerate the collected acid solution,
Furthermore, the regenerated acid solution is supplied to the pickling tank together with a new acid solution.
In the method of collecting, regenerating and supplying the acid solution in the pickling tank,
A method for recovering, regenerating and supplying an acid solution in a pickling tank, wherein hydrofluoric acid is supplied to the filter.

本発明によれば、酸洗槽からの酸液の回収・再生と、同酸洗槽への酸液の供給と、を司る循環系を有する、鋼帯の酸洗設備、焼鈍・酸洗設備および酸洗槽であって、しかも、前記した循環系が、回収した酸液の流れる方向に直列に、ろ過器とイオン交換樹脂とをそなえたものである、前記した、鋼帯の酸洗設備、焼鈍・酸洗設備および酸洗槽での、酸液の回収・再生・供給方法において、前記した、ろ過器に目詰まりが起こるのを防止することができる。 According to the present invention, a steel strip pickling facility, an annealing / pickling facility, having a circulation system that manages the recovery / regeneration of the acid solution from the pickling tank and the supply of the acid solution to the pickling tank. And the pickling equipment for steel strip, wherein the above-mentioned circulation system is provided with a filter and an ion exchange resin in series in the direction in which the recovered acid solution flows. In the method for recovering, regenerating and supplying the acid solution in the annealing / pickling equipment and the pickling tank, it is possible to prevent the filter from being clogged.

発明者らは、ろ過器に目詰まりが起こるのは、回収した酸液中のさまざまな微量元素の中でも、特に、Siが、主な原因となっていることに気付き、そこで、これを弗酸にて溶解し、除去することに想到し、本発明をなすに至ったものである。以下、本発明を具体的に説明する。 The inventors have noticed that Si is the main cause of clogging in the filter, especially among the various trace elements in the collected acid solution, and this is why hydrofluoric acid is removed. The present inventors have conceived that it is dissolved and removed by the above-mentioned method, and have made the present invention. Hereinafter, the present invention will be specifically described.

本発明では、ろ過器に弗酸を供給するようにしたことを特徴とする。なお、本発明にいう弗酸は弗化水素酸水溶液を意味する。なお、本件明細書の説明中に登場する硫酸、塩酸、硝弗酸は、それぞれ、硫酸水溶液、塩酸水溶液、硝酸と弗化水素酸の水溶液を混合したものをそれぞれ意味する。さらに、本発明にいうろ過器は、特許文献1に登場するような、ろ布方式のものでもよいし、その他のものであってもよい。   The present invention is characterized in that hydrofluoric acid is supplied to the filter. The hydrofluoric acid referred to in the present invention means a hydrofluoric acid aqueous solution. In addition, sulfuric acid, hydrochloric acid, and nitric hydrofluoric acid appearing in the description of the present specification mean a sulfuric acid aqueous solution, a hydrochloric acid aqueous solution, and a mixture of nitric acid and hydrofluoric acid aqueous solution, respectively. Furthermore, the filter referred to in the present invention may be of the filter cloth type as shown in Patent Document 1 or may be other types.

(第一の実施の形態)
図1に本発明の実施の形態の一例を示す。
(First embodiment)
FIG. 1 shows an example of an embodiment of the present invention.

図6に示した特許文献1の硫酸酸洗設備に対し、弗酸の循環系90と、付帯していくつかのバルブを追加して設置している。   The sulfuric acid pickling facility of Patent Document 1 shown in FIG. 6 includes a hydrofluoric acid circulation system 90 and some additional valves.

9は弗酸タンクであり、硫酸の循環系60の途中、回収酸タンク3とろ過器4の間、および、ろ過器4とイオン交換樹脂5の間に、それぞれ接続するかたちで、弗酸タンク9に通ずる配管を、バルブ91,92を介して接続している。   A hydrofluoric acid tank 9 is connected to the sulfuric acid circulation system 60, between the recovered acid tank 3 and the filter 4, and between the filter 4 and the ion exchange resin 5. 9 is connected via valves 91 and 92.

弗酸の循環系90は、ろ過器4とその前後の硫酸の循環系60の配管も含むかたちで構成されている。   The hydrofluoric acid circulation system 90 is configured to include the filter 4 and the piping of the sulfuric acid circulation system 60 before and after the filter 4.

硫酸の循環系60の途中、ろ過器4の前後にも、バルブ93,94を介挿するかたちで設置している。   In the middle of the circulation system 60 of sulfuric acid, it is also installed before and after the filter 4 by inserting valves 93 and 94.

図1では、硫酸の循環系60での硫酸の循環を一時停止し、その間に、図示しない機構による圧縮空気などの力で、循環系から硫酸を抜き(液抜きするという)、しかるのち、バルブ91,92を開き、バルブ93,94を閉じて、弗酸タンク9を含む循環系90に、図示しないポンプにて弗酸を循環させ、ろ布方式のろ過器4に弗酸を供給するようにしている。   In FIG. 1, the circulation of sulfuric acid in the sulfuric acid circulation system 60 is temporarily stopped, and during that time, sulfuric acid is extracted from the circulation system by a force such as compressed air (not shown). 91 and 92 are opened, the valves 93 and 94 are closed, and hydrofluoric acid is circulated through a circulation system 90 including the hydrofluoric acid tank 9 by a pump (not shown) to supply hydrofluoric acid to the filter cloth type filter 4. I have to.

硫酸の循環を一時停止するといっても、特許文献1の技術では、ろ過器4のろ布の交換に8時間程度かかっていたのに比し、わずか1時間程度しかかからない。   Even if it is said that the circulation of sulfuric acid is temporarily stopped, it takes only about 1 hour in the technique of Patent Document 1, compared to about 8 hours for replacing the filter cloth of the filter 4.

なお、硫酸の循環を一時停止させなくても済む方法もある。ろ過器4を並列に複数設置し、ある一定の時間、一つのろ過器4に弗酸を供給する間、別のろ過器4は、硫酸の循環に供するようにし、それが終わると、またある一定の時間、先程弗酸を供給していたろ過器4を、硫酸の循環に供するとともに、先程硫酸の循環に供していたろ過器4に弗酸を供給するようにすればよい。以降は、以上の一連の流れの繰り返しである。   There is also a method in which the circulation of sulfuric acid does not have to be temporarily stopped. A plurality of filters 4 are installed in parallel, and while supplying hydrofluoric acid to one filter 4 for a certain period of time, another filter 4 is used for sulfuric acid circulation, and when it is finished, it is also present. The filter 4 previously supplied with hydrofluoric acid for a certain period of time may be used for sulfuric acid circulation, and the hydrofluoric acid may be supplied to the filter 4 previously used for sulfuric acid circulation. Thereafter, the above series of steps is repeated.

ステンレス鋼帯の焼鈍・酸洗を行う操業中は、バルブ91,92を閉じ、バルブ93,94を開いて、硫酸の循環系60に硫酸を通すようにする。   During the operation of annealing and pickling the stainless steel strip, the valves 91 and 92 are closed and the valves 93 and 94 are opened so that the sulfuric acid is passed through the sulfuric acid circulation system 60.

弗酸は、循環させているうちに、Siなどの微量元素の濃度が上がって飽和したり、あるいは、Si以外のSS分(suspended solids)の溶解に費やされたりすることで、Siなどの微量元素をもはや溶解し除去できなくなるため、その場合は、バルブ94を開き、廃酸タンク7に回収したのち、廃棄する。次にろ過器4に弗酸を供給するときは、弗酸タンク9に新しい弗酸を供給することでこれを行う。   While the hydrofluoric acid is circulated, the concentration of trace elements such as Si increases and becomes saturated, or it is spent for dissolving the suspended solids (SS) other than Si. Since trace elements can no longer be dissolved and removed, in this case, the valve 94 is opened, collected in the waste acid tank 7, and then discarded. Next, when supplying hydrofluoric acid to the filter 4, this is done by supplying new hydrofluoric acid to the hydrofluoric acid tank 9.

ろ過器4に弗酸を供給する際の流量は、後述するように、ろ過器4における、例えば高分子製の、ろ布(フィルター)のメッシュの大きさの好適範囲が、0.1〜0.9μmである条件と、ろ布を構成するフィルターの表面積が1mという条件のもとでは、0.1〜10m/hとするのが好ましい。ろ布を構成するフィルターの表面積が変わればそれに比例して変わる。 As will be described later, the flow rate when supplying hydrofluoric acid to the filter 4 is, for example, a suitable range of the mesh size of the filter cloth (filter) made of polymer, for example 0.1 to 0. Under the condition of .9 μm and the condition that the surface area of the filter constituting the filter cloth is 1 m 2 , 0.1 to 10 m 3 / h is preferable. If the surface area of the filter constituting the filter cloth changes, it changes in proportion to it.

0.1m/hを下回ると、Siなどの微量元素を除去する能力が十分でなく、除去に時間がかかりすぎるため、0.1m/h以上とするのが好ましい。 If it is less than 0.1 m 3 / h, the ability to remove trace elements such as Si is not sufficient, and it takes too much time to remove, and therefore it is preferably 0.1 m 3 / h or more.

一方、弗酸の流量は、大きくするほど、Siなどの微量元素を除去するのに要する時間が短くてすむため、上限は特に規定する必要はないが、弗酸タンク9や図1,2などに図示しないポンプの仕様が過大とならない現実性からみて、10m/h以下とするのが好ましい。 On the other hand, the higher the flow rate of hydrofluoric acid, the shorter the time required to remove trace elements such as Si, so there is no need to define the upper limit, but the hydrofluoric acid tank 9 and FIGS. In view of the reality that the specification of the pump (not shown) is not excessive, it is preferable to set it to 10 m 3 / h or less.

なお、本実施の形態にいうろ過器は、特許文献1に登場するような、ろ布方式のものでもよいが、それに限るものではなく、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できるものであれば、その他のものであってもよい。   The filter referred to in the present embodiment may be of the filter cloth type that appears in Patent Document 1, but is not limited thereto, and the maximum value of the particle diameter in one grain is 1. Others may be used as long as they can remove solid particles of 0 μm or more.

(第二の実施の形態)
図2に本発明の別の実施の形態を示す。
(Second embodiment)
FIG. 2 shows another embodiment of the present invention.

弗酸タンク9から回収酸タンク3に通ずるようにバルブ92を介して配管を接続するとともに、硫酸の循環系60の途中、ろ過器4とバルブ94の間に接続するかたちで、回収酸タンク3に通ずる配管を接続している。   A pipe is connected through a valve 92 so as to lead from the hydrofluoric acid tank 9 to the recovered acid tank 3, and the recovered acid tank 3 is connected between the filter 4 and the valve 94 in the middle of the sulfuric acid circulation system 60. The pipe that leads to is connected.

弗酸の循環系90は、ろ過器4とその前後の硫酸の循環系60の配管も含むかたちで構成されている。   The hydrofluoric acid circulation system 90 is configured to include the filter 4 and the piping of the sulfuric acid circulation system 60 before and after the filter 4.

図2では、ステンレス鋼帯の酸洗を行う操業を一時停止し、液抜きしたのち、バルブ92を開き、バルブ94を閉じて、回収酸タンク3とろ過器4を含む弗酸の循環系90に、図示しないポンプにて弗酸を循環させ、ろ過器4に弗酸を供給するようにしている。   In FIG. 2, the operation of pickling the stainless steel strip is temporarily stopped, the liquid is drained, the valve 92 is opened, the valve 94 is closed, and the hydrofluoric acid circulation system 90 including the recovered acid tank 3 and the filter 4 is used. In addition, hydrofluoric acid is circulated by a pump (not shown) to supply hydrofluoric acid to the filter 4.

弗酸は、循環させているうちに、Siなどの微量元素の濃度が上がって飽和したり、あるいは、Si以外のSS分(suspended solids)の溶解に費やされたりすることで、Siなどの微量元素をもはや溶解し除去できなくなるため、その場合は、バルブ94を開き、廃酸タンク7に回収したのち、廃棄する。次にろ過器4に弗酸を供給するときは、弗酸タンク9に新しい弗酸を供給することでこれを行う。   While the hydrofluoric acid is circulated, the concentration of trace elements such as Si increases and becomes saturated, or it is spent for dissolving the suspended solids (SS) other than Si. Since trace elements can no longer be dissolved and removed, in this case, the valve 94 is opened, collected in the waste acid tank 7, and then discarded. Next, when supplying hydrofluoric acid to the filter 4, this is done by supplying new hydrofluoric acid to the hydrofluoric acid tank 9.

ろ過器4に弗酸を供給する際の流量は、ろ過器4における、例えば高分子製の、ろ布(フィルター)のメッシュの大きさの好適範囲が、0.1〜0.9μmである条件と、ろ布を構成するフィルターの表面積が1mという条件のもとでは、0.1〜10m/hとするのが好ましく、ろ布を構成するフィルターの表面積が変わればそれに比例して変わる。この点は、好ましい理由も含め、先述の第一の実施の形態の場合と同じである。 The flow rate when supplying hydrofluoric acid to the filter 4 is such that the preferred range of the mesh size of the filter cloth (filter) made of, for example, polymer in the filter 4 is 0.1 to 0.9 μm. And, under the condition that the surface area of the filter constituting the filter cloth is 1 m 2 , it is preferably 0.1 to 10 m 3 / h, and if the surface area of the filter constituting the filter cloth is changed, it will be proportionally changed. . This point is the same as in the case of the first embodiment described above, including the preferable reason.

また、本実施の形態にいうろ過器は、特許文献1に登場するような、ろ布方式のものでもよいが、それに限るものではなく、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できるものであれば、その他のものであってもよい点も、先述の第一の実施の形態の場合と同じである。   The filter referred to in the present embodiment may be of the filter cloth type that appears in Patent Document 1, but is not limited to this, and the maximum value of the particle diameter in one grain is 1. As long as the solid particles of 0 μm or more can be removed, other points may be the same as in the case of the first embodiment described above.

(その他の好ましい実施の形態)
以上が本発明の構成上の特徴部分についての好ましい実施の形態に関する説明であるが、それ以外の部分についての好ましい実施の形態に関して、以下に説明する。
(Other preferred embodiments)
The above is a description of a preferred embodiment of the structural features of the present invention, but a preferred embodiment of the other portions will be described below.

以上説明した二つの実施の形態で使用する、ろ過器4における、例えば高分子製の、ろ布(フィルター)のメッシュの大きさは、0.1〜0.9μmとするのが好ましい。   The size of the mesh of the filter cloth (filter) made of, for example, polymer in the filter 4 used in the two embodiments described above is preferably 0.1 to 0.9 μm.

ちなみに、このメッシュの大きさは、最大の面積のメッシュと同面積の円の直径で表した値である。メッシュの大きさが0.9μmを超えると、本発明で目標とする一つの粒内での粒径の最大値が1.0μm以上のスケールを完全に除去することができず、一方0.1μm未満では、回収した酸液の流量が最大2m/hにも及ぶステンレス鋼帯の硫酸酸洗では、ろ過能力の点で問題が生じるからである。 Incidentally, the size of this mesh is a value represented by the diameter of a circle having the same area as that of the mesh having the largest area. When the size of the mesh exceeds 0.9 μm, it is impossible to completely remove a scale having a maximum particle size of 1.0 μm or more in one grain targeted in the present invention, while 0.1 μm. This is because, in the case of the sulfuric acid pickling of the stainless steel strip in which the flow rate of the collected acid solution reaches 2 m 3 / h at the maximum, there is a problem in terms of filtration capacity.

また、図1,図2では、イオン交換樹脂5の上流に設置するろ過器4の台数が1台の場合についてだけ示したが、台数は複数であってもよい。その場合には、全てのろ過器が、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できるものである必要はなく、少なくとも1台が、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できるものであれば、残りは一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できないものや、従来の砂ろ過器等を用いてもよい。   1 and 2 show only the case where the number of the filters 4 installed upstream of the ion exchange resin 5 is one, the number may be plural. In that case, it is not necessary for all the filters to be able to remove solid particles having a maximum particle size of 1.0 μm or more in one particle, and at least one unit is in one particle. If the solid particles having a maximum particle size of 1.0 μm or more can be removed, the remainder cannot remove solid particles having a maximum particle size of 1.0 μm or more in one particle, A sand filter or the like may be used.

上記のようにして一つの粒内での粒径の最大値が1.0μm以上の微細スケールが除去された硫酸は、イオン交換樹脂5に導かれる。   The sulfuric acid from which the fine scale having a maximum particle size of 1.0 μm or more in one grain is removed as described above is guided to the ion exchange resin 5.

このイオン交換樹脂5は、図3(a)に示すような構造になっている。ここで、図3(b)に示すように、H+ やSO42- のような遊離酸はイオン交換樹脂5に吸着される一方、FeSO4 等の結合酸はイオン交換樹脂5を透過して、廃酸として硫酸の循環系60の外に排出される。   The ion exchange resin 5 has a structure as shown in FIG. Here, as shown in FIG. 3 (b), free acids such as H + and SO42- are adsorbed to the ion exchange resin 5, while binding acids such as FeSO4 permeate the ion exchange resin 5 and are discarded. The acid is discharged out of the sulfuric acid circulation system 60.

一方、遊離酸が吸着されたイオン交換樹脂5に水を供給すると、イオン交換樹脂5に吸着された硫酸イオンを水に溶解させて回収することができる。   On the other hand, when water is supplied to the ion exchange resin 5 on which the free acid is adsorbed, sulfate ions adsorbed on the ion exchange resin 5 can be dissolved in water and recovered.

とはいえ、H+ やSO42- のような遊離酸をイオン交換樹脂5に吸着する動作と、イオン交換樹脂5に吸着された硫酸イオンを水に溶解させて回収する動作は、同時に行えるわけではないため、前者をある一定の時間実施したあと後者をある一定の時間実施する、という動作を繰り返し行うことになる。   However, the operation of adsorbing free acids such as H + and SO42- on the ion exchange resin 5 and the operation of dissolving and recovering the sulfate ions adsorbed on the ion exchange resin 5 in water cannot be performed simultaneously. Therefore, the operation of performing the former for a certain time and then performing the latter for a certain time is repeated.

すると、後者を実施している時間の間、前者が実施できなくなって操業を停止せざるを得ないため、次のようにするのが好ましい。   Then, during the time when the latter is carried out, the former cannot be carried out and the operation has to be stopped. Therefore, the following is preferable.

すなわち、イオン交換樹脂5を2つ以上並列して備えておき、1つのイオン交換樹脂で前者を実施している時間の間、他のイオン交換樹脂で後者を実施しておき、その時間の経過後、他のイオン交換樹脂で前者を実施する、という動作を繰り返すようにするのが好ましい。   That is, two or more ion exchange resins 5 are provided in parallel, while the former is carried out with one ion exchange resin, the latter is carried out with another ion exchange resin, and the passage of the time Thereafter, it is preferable to repeat the operation of performing the former with another ion exchange resin.

ところで、かようなイオン交換樹脂5としては、アニオン交換樹脂が有利に適合する。
アニオン交換樹脂の例としては、
1)アリル基を3個ないし4個含む第四アンモニウム塩を重合または共重合させたもの、
2)芳香族モノアミンまたはジアミンとホルマリンを強塩基性で縮合させたもの、
3)脂肪族モノアミン、グアニジン、ポリエチレンポリアミンなどとホルマリンおよびフェノール類を縮合させたもの、
4)フェノール樹脂にマンニッヒ反応により第三アミノ基を導入したもの、
5)スチレン(−ジビニルベンゼン)共重合体をクロルメチル化したのち、第三アミンと反応させたもの、
6)スチレン共重合体またはフェノール樹脂などをニトロ化還元したもの、
7)シアン基をもつ重合体を還元したもの
などが好適である。
By the way, as such an ion exchange resin 5, an anion exchange resin is advantageously adapted.
Examples of anion exchange resins include
1) Polymerized or copolymerized quaternary ammonium salt containing 3 to 4 allyl groups,
2) A strongly condensed basic monoamine or diamine and formalin,
3) Condensation of aliphatic monoamine, guanidine, polyethylene polyamine, etc. with formalin and phenols,
4) A phenolic resin having a tertiary amino group introduced by the Mannich reaction,
5) A styrene (-divinylbenzene) copolymer that has been chloromethylated and then reacted with a tertiary amine,
6) Nitrogen-reduced styrene copolymer or phenol resin
7) A polymer obtained by reducing a polymer having a cyan group is suitable.

かくして、回収された硫酸は、供給酸タンク6に送られ、ここで必要に応じて新規の硫酸と混合されて、硫酸酸洗槽1に供給される。   Thus, the recovered sulfuric acid is sent to the supply acid tank 6, where it is mixed with new sulfuric acid as necessary, and supplied to the sulfuric acid pickling tank 1.

以上、硫酸酸洗槽1における硫酸の回収・再生・供給方法について説明したが、本発明では、硝弗酸酸洗槽から回収した硝弗酸の再生・供給も、併せて行うことができる。この硝弗酸の回収・再生・供給も、前出の図6と同様な循環系をそなえるようにした上で行うことができる。   The method for recovering, regenerating and supplying sulfuric acid in the sulfuric acid pickling tank 1 has been described above. However, in the present invention, regeneration and supply of nitric hydrofluoric acid recovered from the nitric hydrofluoric acid washing tank can be performed together. The recovery, regeneration, and supply of this nitric hydrofluoric acid can also be performed after providing a circulation system similar to that shown in FIG.

但し、硝弗酸による酸洗に際しては、微細なスケールはほとんど除去されているので、ろ過器としては、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できるろ過器を用いる必要性は小さく、砂ろ過器のような一般的なろ過器でも十分である。勿論、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できるろ過器を用いても別段支障はない。   However, when pickling with nitric hydrofluoric acid, most of the fine scale has been removed, so the filter can remove solid particles with a maximum particle size of 1.0 μm or more in one particle. The need to use a filter is small, and a general filter such as a sand filter is sufficient. Of course, there is no particular problem even if a filter capable of removing solid particles having a maximum particle size of 1.0 μm or more in one particle is used.

さらに、本発明は、ステンレス鋼帯の酸洗だけでなく、普通鋼帯とも呼ばれる炭素鋼帯の酸洗にも適用することができる。炭素鋼帯の酸洗は、多くの場合、塩酸を用い、炭素鋼帯の酸洗設備は、多くの場合、焼鈍炉を伴わないが、酸液の循環系は、図6に示したものと同じである。ろ過器は一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できるものとし、イオン交換樹脂は、ステンレス鋼帯の酸洗の場合と同じく、アニオン交換樹脂とすればよい。   Furthermore, the present invention can be applied not only to pickling of stainless steel strips, but also to pickling of carbon steel strips, which are also called ordinary steel strips. The pickling of the carbon steel strip often uses hydrochloric acid, and the pickling equipment for the carbon steel strip often does not involve an annealing furnace, but the circulation system of the acid solution is as shown in FIG. The same. The filter is capable of removing solid particles having a maximum particle size of 1.0 μm or more in one grain, and the ion exchange resin is an anion exchange resin as in the case of pickling stainless steel strip. Good.

上記のようにして、酸液を回収・再生・供給することにより、酸液中の金属濃度を金属塩析出濃度以下に維持することができるので、酸洗槽で生成するスラッジを低減できる。その結果、酸洗槽でのスラッジの析出量、堆積量も減少するので、従来に比べ定期清掃の頻度を大幅に減らすことができる。   By collecting, regenerating, and supplying the acid solution as described above, the metal concentration in the acid solution can be maintained below the metal salt precipitation concentration, so that sludge generated in the pickling tank can be reduced. As a result, the amount of sludge deposited and deposited in the pickling tank is also reduced, so that the frequency of regular cleaning can be greatly reduced as compared with the conventional case.

図1に示すように、ステンレス鋼帯の焼鈍・酸洗設備(能力5万ton/月)のうちの硫酸酸洗槽1について、硫酸の循環系60の途中に、弗酸の循環系90を設置して、硫酸を30日間(1ヶ月)循環使用した。そして、ろ布方式のろ過器4に、弗酸を供給した。 As shown in FIG. 1, a hydrofluoric acid circulation system 90 is placed in the middle of a sulfuric acid circulation system 60 in the sulfuric acid pickling tank 1 of a stainless steel strip annealing / pickling facility (capacity 50,000 ton / month). Once installed, sulfuric acid was circulated for 30 days (1 month). Then, hydrofluoric acid was supplied to the filter cloth type filter 4.

このろ布方式のろ過器4は、メッシュの大きさが0.2μm×0.2μm(円形換算直径0.1μm)であり、1本あたりの表面積が1mのフィルターを4本そなえ、合計で表面積が4mのものを用いている。 This filter cloth type filter 4 has a mesh size of 0.2 μm × 0.2 μm (circular conversion diameter: 0.1 μm), and has four filters each having a surface area of 1 m 2. A surface area of 4 m 2 is used.

弗酸タンク9には2mの弗酸を満たして、ろ布方式のろ過器4に、弗酸を供給した。 The hydrofluoric acid tank 9 was filled with 2 m 3 of hydrofluoric acid, and the hydrofluoric acid was supplied to the filter cloth type filter 4.

その他の条件は以下のとおりである。
・硫酸酸洗槽1における硫酸濃度:25mass%、温度:75℃
・回収した酸液の流量:2m/h(酸洗槽1槽あたり)
・イオン交換樹脂:アニオン交換樹脂
・ろ布方式のろ過器への弗酸の供給:フィルター1本ずつ、操業への供用と弗酸の供給を切り替えて実施
・ろ布方式のろ過器のフィルター1本への弗酸の供給流量と時間:流量は1m/h、弗酸を供給した時間は2時間とした。
Other conditions are as follows.
-Sulfuric acid concentration in the sulfuric acid washing tank 1: 25 mass%, temperature: 75 degreeC
・ Flow rate of collected acid solution: 2 m 3 / h (per pickling tank)
・ Ion exchange resin: Anion exchange resin ・ Supply hydrofluoric acid to filter type filter: Switch one filter at a time for operation and hydrofluoric acid supply ・ Filter 1 for filter type filter Supply flow rate and time of hydrofluoric acid to the book: The flow rate was 1 m 3 / h, and the supply time of hydrofluoric acid was 2 hours.

本発明の硫酸酸洗設備を用いることにより、ろ布方式のろ過器4の目詰まりは解消し、ステンレス鋼帯の搬送速度:50m/min、硫酸酸洗槽1槽あたりの回収した酸液の流量:2m/hという高速通板、大流量回収の条件下においても、何ら支障なくステンレス鋼帯の硫酸酸洗を行うことができた。 By using the sulfuric acid pickling facility of the present invention, clogging of the filter cloth type filter 4 is eliminated, the transport speed of the stainless steel strip: 50 m / min, and the collected acid solution per one sulfuric acid pickling tank. Even under the conditions of high flow rate of flow rate: 2 m 3 / h and recovery of a large flow rate, the sulfuric acid pickling of the stainless steel strip could be performed without any trouble.

本発明の実施の形態の一例について説明するための線図Diagram for explaining an example of an embodiment of the present invention 本発明の別の実施の形態について説明するための線図Diagram for explaining another embodiment of the present invention イオン交換樹脂による硫酸の回収要領を示した図である。It is the figure which showed the collection | recovery point of the sulfuric acid by an ion exchange resin. ステンレス鋼帯の焼鈍・酸洗設備を示した図である。It is the figure which showed the annealing and pickling equipment of a stainless steel strip. 従来の硫酸酸洗設備における硫酸の循環系を示した図である。It is the figure which showed the circulation system of the sulfuric acid in the conventional sulfuric acid pickling equipment. 本発明に従う硫酸の循環系を備える硫酸酸洗設備の模式図である。It is a schematic diagram of a sulfuric acid pickling equipment provided with the circulation system of sulfuric acid according to the present invention.

符号の説明Explanation of symbols

1 硫酸酸洗槽(酸洗槽)
2 硫酸循環タンク(循環タンク)
3 回収酸タンク
4 ろ過器
5 イオン交換樹脂
6 供給酸タンク
7 廃酸タンク
8 硝弗酸酸洗槽
9 弗酸タンク
60 硫酸の循環系
90 弗酸の循環系
91,92,93,94 バルブ
S 鋼帯
1 Sulfate pickling tank (Pickling tank)
2 Sulfuric acid circulation tank (circulation tank)
3 Recovery Acid Tank 4 Filter 5 Ion Exchange Resin 6 Supply Acid Tank 7 Waste Acid Tank 8 Nitric Hydrofluoric Acid Washing Tank 9 Hydrofluoric Acid Tank 60 Sulfuric Acid Circulation System 90 Hydrofluoric Acid Circulation System 91, 92, 93, 94 Valve S Steel strip

Claims (7)

硫酸酸洗槽と硝弗酸酸洗槽を被処理ステンレス鋼帯の搬送方向に直列に並べ、
前記硫酸酸洗槽は、前記硫酸酸洗槽からの酸液の回収・再生・供給を司る硫酸の循環系を有し、
該循環系は、回収した酸液の流れる方向に直列に、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去できるろ過器と、イオン交換樹脂とをそなえたステンレス鋼帯の酸洗設備において、
前記ろ過器に弗酸を供給するようにした
ことを特徴とするステンレス鋼帯の酸洗設備。
A sulfuric acid pickling tank and a nitric hydrofluoric acid pickling tank are arranged in series in the conveying direction of the stainless steel strip to be treated.
The sulfuric acid pickling tank has a sulfuric acid circulation system that manages recovery, regeneration, and supply of the acid solution from the sulfuric acid pickling tank,
The circulatory system is a stainless steel provided with a filter capable of removing solid particles having a maximum particle size of 1.0 μm or more in one particle in series with the flow direction of the collected acid solution, and an ion exchange resin. In pickling equipment for steel strips,
A pickling facility for a stainless steel strip, characterized in that hydrofluoric acid is supplied to the filter.
請求項1のステンレス鋼帯の酸洗設備であって、
前記硫酸酸洗槽に加え、前記硝弗酸酸洗槽も、前記硝弗酸酸洗槽からの酸液の回収・再生・供給を司る硝弗酸の循環系を有する
ことを特徴とするステンレス鋼帯の酸洗設備。
The pickling equipment for the stainless steel strip according to claim 1,
In addition to the sulfuric acid pickling tank, the nitric hydrofluoric acid washing tank also has a nitric hydrofluoric acid circulation system that manages recovery, regeneration, and supply of the acid solution from the nitric hydrofluoric acid washing tank. Steel strip pickling equipment.
酸洗槽を被処理鋼帯の搬送方向に直列に並べ、
前記酸洗槽は、前記酸洗槽からの酸液の回収・再生・供給を司る酸液の循環系を有し、
該循環系は、回収した酸液の流れる方向に直列に、ろ過器とイオン交換樹脂とをそなえた鋼帯の酸洗設備において、
前記ろ過器に弗酸を供給するようにした
ことを特徴とする鋼帯の酸洗設備。
The pickling tanks are arranged in series in the conveying direction of the steel strip to be treated,
The pickling tank has an acid solution circulation system that manages recovery, regeneration, and supply of the acid solution from the pickling tank,
The circulation system is a steel strip pickling facility provided with a filter and an ion exchange resin in series with the direction in which the collected acid solution flows.
A steel strip pickling facility characterized in that hydrofluoric acid is supplied to the filter.
請求項1乃至請求項3のいずれかの酸洗設備の搬送方向上流側に、さらに焼鈍炉を備えた
ことを特徴とする鋼帯の焼鈍・酸洗設備。
An annealing / pickling facility for steel strip, further comprising an annealing furnace on the upstream side in the transport direction of the pickling facility according to any one of claims 1 to 3.
硫酸酸洗槽から回収した硫酸を、ろ過器に導いて、前記回収した硫酸中に含まれる、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去したのち、
イオン交換樹脂に導いて、前記回収した硫酸中の硫酸イオンをイオン交換樹脂に吸着させ、
ついで、硫酸イオンが吸着したイオン交換樹脂に、水を供給して、前記イオン交換樹脂に吸着した硫酸イオンを、水に溶解させて、前記回収した硫酸を再生し、
さらに、再生した硫酸を、新しい硫酸と一緒に前記硫酸酸洗槽に供給する、
硫酸酸洗槽での、硫酸の回収・再生・供給方法において、
前記ろ過器に弗酸を供給するようにした
ことを特徴とする硫酸酸洗槽での、硫酸の回収・再生・供給方法。
The sulfuric acid recovered from the sulfuric acid washing tank is guided to a filter, and after removing solid particles having a maximum particle size of 1.0 μm or more contained in the recovered sulfuric acid within one particle,
Lead to an ion exchange resin, adsorb the sulfate ions in the recovered sulfuric acid to the ion exchange resin,
Next, water is supplied to the ion exchange resin on which sulfate ions are adsorbed, and the sulfate ions adsorbed on the ion exchange resin are dissolved in water to regenerate the recovered sulfuric acid,
Furthermore, the regenerated sulfuric acid is supplied to the sulfuric acid washing tank together with fresh sulfuric acid.
In the method of sulfuric acid recovery / regeneration / supply in the sulfuric acid pickling tank,
A method for recovering, regenerating and supplying sulfuric acid in a sulfuric acid washing tank, wherein hydrofluoric acid is supplied to the filter.
硫酸酸洗槽から回収した硫酸を、ろ過器に導いて、前記回収した硫酸中に含まれる、一つの粒内での粒径の最大値が1.0μm以上の固形粒子を除去したのち、
イオン交換樹脂に導いて、前記回収した硫酸中の硫酸イオンをイオン交換樹脂に吸着させ、
ついで、硫酸イオンが吸着したイオン交換樹脂に、水を供給して、前記イオン交換樹脂に吸着した硫酸イオンを、水に溶解させて、前記回収した硫酸を再生し、
さらに、再生した硫酸を、新しい硫酸と一緒に前記硫酸酸洗槽に供給するようにするとともに、
硝弗酸酸洗槽から回収した硝弗酸を、ろ過したのち、
イオン交換樹脂に導いて、前記回収した硝弗酸中の金属イオンをイオン交換樹脂に吸着させることにより、前記回収した硝弗酸を再生し、
さらに、再生した硝弗酸を、新しい硝弗酸と一緒に前記硝弗酸酸洗槽に供給する、
硫酸酸洗槽および硝弗酸酸洗槽での、酸液の回収・再生・供給方法において、
前記ろ過器に弗酸を供給するようにした
ことを特徴とする硫酸酸洗槽での、硫酸の回収・再生・供給方法。
The sulfuric acid recovered from the sulfuric acid washing tank is guided to a filter, and after removing solid particles having a maximum particle size of 1.0 μm or more contained in the recovered sulfuric acid within one particle,
Lead to an ion exchange resin, adsorb the sulfate ions in the recovered sulfuric acid to the ion exchange resin,
Next, water is supplied to the ion exchange resin on which sulfate ions are adsorbed, and the sulfate ions adsorbed on the ion exchange resin are dissolved in water to regenerate the recovered sulfuric acid,
Furthermore, the regenerated sulfuric acid is supplied to the sulfuric acid washing tank together with fresh sulfuric acid,
After filtering the nitric hydrofluoric acid recovered from the nitric hydrofluoric acid washing tank,
Reducing the recovered nitrohydrofluoric acid by guiding it to the ion exchange resin and adsorbing the metal ions in the recovered nitrohydrofluoric acid to the ion exchange resin,
Furthermore, the regenerated nitric hydrofluoric acid is supplied to the nitric hydrofluoric acid washing tank together with new nitric hydrofluoric acid.
In the method for recovering, regenerating and supplying the acid solution in the sulfuric acid pickling tank and the nitric hydrofluoric acid pickling tank,
A method for recovering, regenerating and supplying sulfuric acid in a sulfuric acid washing tank, wherein hydrofluoric acid is supplied to the filter.
酸洗槽から回収した酸液を、ろ過器に導いて、前記回収した酸液中に含まれる、一つの粒内で粒径の最大値が1.0μm以上の固形粒子を除去したのち、
イオン交換樹脂に導いて、前記回収した酸液中の酸イオンをイオン交換樹脂に吸着させ、
ついで、酸イオンが吸着したイオン交換樹脂に、水を供給して、前記イオン交換樹脂に吸着した酸イオンを、水に溶解させて、前記回収した酸液を再生し、
さらに、再生した酸液を、新しい酸液と一緒に酸洗槽に供給する、
酸洗槽での、酸液の回収・再生・供給方法において、
前記ろ過器に弗酸を供給するようにした
ことを特徴とする酸洗槽での、酸液の回収・再生・供給方法。
The acid solution collected from the pickling tank is guided to a filter, and after removing solid particles having a maximum particle size of 1.0 μm or more contained in one of the grains contained in the collected acid solution,
Lead to ion exchange resin, adsorb acid ions in the collected acid solution to ion exchange resin,
Next, water is supplied to the ion exchange resin on which the acid ions are adsorbed, and the acid ions adsorbed on the ion exchange resin are dissolved in water to regenerate the collected acid solution,
Furthermore, the regenerated acid solution is supplied to the pickling tank together with a new acid solution.
In the method of collecting, regenerating and supplying the acid solution in the pickling tank,
A method for recovering, regenerating and supplying an acid solution in a pickling tank, wherein hydrofluoric acid is supplied to the filter.
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