JP3100410B2 - Salt bath treatment method - Google Patents
Salt bath treatment methodInfo
- Publication number
- JP3100410B2 JP3100410B2 JP03068649A JP6864991A JP3100410B2 JP 3100410 B2 JP3100410 B2 JP 3100410B2 JP 03068649 A JP03068649 A JP 03068649A JP 6864991 A JP6864991 A JP 6864991A JP 3100410 B2 JP3100410 B2 JP 3100410B2
- Authority
- JP
- Japan
- Prior art keywords
- salt
- solution
- salt bath
- bath
- treatment
- 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.)
- Expired - Fee Related
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Description
【０００１】[0001]
【産業上の利用分野】この発明は塩浴液の処理方法に関
し、特に、ソルト( 塩浴) 処理したステンレス鋼の急冷
処理の際に発生する排液や、鋼材の塩浴槽内に蓄積した
沈澱物に付着した塩の洗浄など際に発生する排液を処理
する場合に、必要とする薬剤として身近な処理系列の排
液を利用でき、しかも有害性物質の除去を行える塩浴液
の処理方法に関する。さらにこの発明は、特にステンレ
ス系の鋼材の処理を必要とする分野であって、排液に含
まれる薬剤が環境問題と関連を持つような分野に応用で
きる塩浴液の処理方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a salt bath, and more particularly, to a wastewater generated during a quenching process of salt-treated stainless steel, and a precipitation of steel material accumulated in a salt bath. When treating effluent generated during washing of salt attached to a substance, a method of treating a salt bath that can use effluent of a familiar treatment series as a necessary chemical and can remove harmful substances About. Further, the present invention relates to a method for treating a salt bath liquid which can be applied particularly to a field which requires the treatment of a stainless steel material, in which a chemical contained in the effluent is related to an environmental problem.
【０００２】[0002]
【従来の技術】ステンレス鋼のソルト処理の塩浴より持
ち出された浴組成薬剤は、高価であると同時に、中和処
理でもその塩を不溶解性に変えることができず、排水に
含まれると富栄養化の窒素源としての硝酸根となるた
め、これの除去が問題になってきている。2. Description of the Related Art Bath composition chemicals taken out of a salt bath for salt treatment of stainless steel are expensive, and at the same time, their salts cannot be converted to insoluble by neutralization treatment. Since it becomes nitrate as a nitrogen source for eutrophication, its removal has become a problem.
【０００３】これらの浴組成の主成分である硝酸曹達は
可溶性塩であり、排水のために系より取り出すには、濃
縮操作を行う以外に方法がない。さらに濃縮されたもの
でも、現実の応用を考えると、無水の塩にしないと再利
用はできない。[0003] Nitric acid nitrates, which are the main components of these bath compositions, are soluble salts, and there is no other way to remove them from the system for drainage, except by performing a concentration operation. Even in a more concentrated form, considering its practical application, it cannot be reused unless it is made into an anhydrous salt.
【０００４】さらにこのソルト浴より持ち出されてくる
薬剤には、処理されるステンレス鋼を構成する組成の一
つであるクローム分子が含まれるが、このクローム分子
は、処理温度が高いことからCr3+よりCr6+に変化する。
このCr6+は水に対し可溶性になると同時に、毒性が強
い。このため、公害対策としての処理の確実性が要求さ
れるが、その管理が難しいため、廃棄物処理上の問題が
生じる。[0004] More drugs from coming taken out is in the salt bath, but are chrome molecule is one of the compositions constituting the stainless steel being processed, the chrome molecule, Cr 3 since the processing temperature is high Changes from + to Cr 6+ .
This Cr 6+ becomes soluble in water and is highly toxic. For this reason, certainty of treatment is required as a countermeasure against pollution, but since its management is difficult, there is a problem in waste disposal.
【０００５】このため従来では、Cr6+に還元性のある薬
品を共存させてCr3+に還元し、凝集処理による除去をお
こなっている。しかし、水系よりの硝酸根の除去はでき
ていない。Therefore, conventionally, Cr 6+ is reduced to Cr 3+ in the coexistence of a reducing agent, and is removed by a coagulation treatment. However, nitrate groups have not been removed from the water system.
【０００６】あるいは、６価クロームの還元剤として、
外部より２価の鉄金属塩を購入し、目的の処理に用いる
ようにしたものも提案されている。特開平２−145786号
公報には、酸洗浴の遊離酸を拡散透析膜を用いて回収
し、その一方で発生する金属成分を主成分とする排液
を、還元中和剤として利用することが記載されている。
しかし、急冷処理を終えた液に含まれている硝酸根を濃
縮し、遊離硝酸と苛性曹達に分離回収して再利用を進
め、排出水の中に含有される薬剤量を削減する方向への
努力については、何ら記載されていない。Alternatively, as a hexavalent chromium reducing agent,
A proposal has been made in which a divalent iron metal salt is purchased from the outside and used for the intended treatment. Japanese Patent Application Laid-Open No. 2-145786 discloses that a free acid in a pickling bath is recovered using a diffusion dialysis membrane, and on the other hand, an effluent containing a metal component as a main component is used as a reducing neutralizer. Are listed.
However, the nitrate groups contained in the quenched solution are concentrated, separated and collected into free nitric acid and caustic soda for reuse, and the amount of chemicals contained in the discharged water is reduced. No mention is made of the effort.
【０００７】[0007]
【発明が解決しようとする課題】ソルト浴に用いられて
いる薬剤は、高価であると同時に、溶存液より分離して
濃縮するのが難しいという特性を持っている。The chemical used in the salt bath is expensive and has characteristics that it is difficult to separate and concentrate it from the dissolved solution.
【０００８】一方、硝酸系酸処理液における老化酸浴液
は、一般に単独で中和されかつ排出されているが、硝酸
系酸処理液の老化酸浴液中に含まれる鉄分の一部は、6
価クロームの還元に有効に作用する。したがって、これ
らの液を混合することで、使用すべき薬剤の削減のため
の方向づけが可能となる。On the other hand, the aging acid bath solution in the nitric acid-based treatment solution is generally neutralized and discharged alone, but a part of the iron contained in the aging acid bath solution of the nitric acid-based treatment solution is: 6
Effectively acts on reduction of valent chromium. Therefore, by mixing these liquids, it is possible to make an orientation for reducing the amount of the medicine to be used.
【０００９】そこでこの発明は、同じ操作を行っている
工場内の他の発生箇所より、還元機能を有する薬剤を選
びだし、これを、処理液中に含有される有毒かつ可溶性
のクローム化合物に有効に作用させる。そして、資源の
有効な利用を図って、硝酸根含有液系に含有する塩を再
度遊離酸として回収すると同時に、これをアルカリ剤と
して回収し、工程中における利用箇所の応用を図ること
で上述の問題点を解決することを目的とする。Therefore, the present invention selects an agent having a reducing function from other sites in a factory where the same operation is performed, and applies the agent to a toxic and soluble chromium compound contained in a processing solution. To act on. Then, with the aim of effective use of resources, the salt contained in the nitrate-containing liquid system is recovered again as a free acid, and at the same time, this is recovered as an alkali agent, and the above-mentioned application of the used portion in the process is carried out. The purpose is to solve the problem.
【００１０】[0010]
【課題を解決するための手段】上記目的を達成するため
この発明は、硝酸塩化合物または苛性曹達を組成とした
塩浴を用いて鋼材の表面処理を施すに際し、高温溶融炉
に浸漬されて取り出された後の鋼材を水中に浸漬して冷
却を行うことで発生する溢れ液と、この冷却処理を終え
た鋼材に付着したアルカリ剤を中和することで発生する
溢れ液と, 前記塩浴の底に堆積しかつ取り出された鋼滓
に付着した塩浴組成物の除去のための洗浄時に発生する
洗浄液とに含まれる組成薬剤を回収するために、処理鋼
材組成中のクローム金属化合物が塩浴中で６価の水溶性
塩に変化して溶存している前記各溶液の混合液中のこれ
ら化合物を、還元化後に不溶性水酸化物処理し、この処
理のための薬剤として、前記鋼材を浸漬酸洗い処理する
ための少なくとも硝酸を含む浴に溶解する金属イオンを
含有し、かつ遊離酸を残す酸液の一部を、前記混合液の
還元剤として、その中和操作後の液に注入し、この還元
反応の環境を高温かつ酸性を維持したものとして、処理
対象液に含まれている６価の塩を３価に還元させ、その
後、苛性曹達でアルカリ性にすることで、溶解金属物
を、不溶解アルカリ剤の混入なしに、不溶解性金属水酸
化固形物と、可溶性硝酸曹達や苛性曹達などの可溶性塩
液とに分離する。SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for performing a surface treatment of a steel material using a salt bath containing a nitrate compound or caustic soda, which is immersed in a high-temperature melting furnace and taken out. The overflow liquid generated by immersing the steel material after cooling in water and cooling, the overflow liquid generated by neutralizing the alkali agent attached to the steel material after the cooling treatment, and the bottom of the salt bath In order to recover the composition chemicals contained in the cleaning liquid generated during the cleaning for removing the salt bath composition attached to the steel slag removed and removed from the steel slag, the chromium metal compound in the treated steel composition is removed from the salt bath. These compounds in the mixed solution of the above-mentioned solutions, which have been converted to and dissolved in hexavalent water-soluble salts, are subjected to an insoluble hydroxide treatment after reduction, and as a chemical for this treatment, the steel is immersed in acid. At least for the washing process A part of an acid solution containing metal ions dissolved in a bath containing an acid and leaving a free acid is injected as a reducing agent of the mixed solution into the solution after the neutralization operation, and the environment of this reduction reaction is reduced. Assuming that high temperature and acidity are maintained, the hexavalent salt contained in the liquid to be treated is reduced to trivalent, and then alkalized with caustic soda to mix dissolved metal substances with an insoluble alkali agent. Without separation into insoluble metal hydroxide solids and soluble salt solutions such as soluble nitrate and caustic soda.
【００１１】[0011]
【作用】塩浴（ソルト）を構成する組成の持つ特徴は、
次の通りである。 (A) ソルト溶液の組成は苛性曹達と硝酸曹達が主成分で
あり、これらの薬剤は、溶解してきた金属との塩の形で
この金属を溶解させており、含有金属イオン濃度は高
い。 (B) ソルト浴内は 400〜600 ℃と高温なので、溶解クロ
ーム化合物は６価に酸化された安定な化合物に変化して
溶存する。 (C) その他の金属も塩の形で溶解しており、これらの化
合物は、急冷処理のための水に接触すると液系に溶解
し、排水側に移行する。しかし、アルカリ性であって6
価に酸化されたクロームは可溶性であるが、他は不溶性
であり、分散物を分離すると、イ) 可溶性中性塩〜硝酸
曹達と、ロ) アルカリ剤〜苛性曹達と、ハ) 分散微粒子
〜金属の酸化物・水酸化物とに分離される。 (D) 一方、ステンレス鋼の表面処理を目的とする工場
は、同時に硝酸浴を用いた処理浴を持つのが一般的であ
り、その浴での金属の溶解により浴の持つべき機能が無
くなるため、廃棄処理をしなければならない。ところ
で、その浴液には２価の鉄分が含有しており、特に硝酸
酸化された鉄の持つ還元力は強く、効率よく６価クロー
ムを還元してまず毒性を削減させ、さらにクロームの水
酸化物として分離させる機能を持っている。[Action] The characteristics of the composition constituting the salt bath (salt) are as follows:
It is as follows. (A) The composition of the salt solution is mainly composed of caustic soda and nitrate, and these chemicals dissolve this metal in the form of a salt with the dissolved metal, and the contained metal ion concentration is high. (B) Since the temperature in the salt bath is as high as 400 to 600 ° C., the dissolved chromium compound changes to a hexavalent oxidized stable compound and dissolves. (C) Other metals are also dissolved in the form of a salt, and when these compounds come into contact with water for quenching treatment, they dissolve in the liquid system and migrate to the drainage side. However, it is alkaline and 6
The chromium oxidized to a valence is soluble, but the others are insoluble, and when the dispersion is separated, a) soluble neutral salts to sodium nitrate, b) alkaline agents to caustic soda, and c) dispersed fine particles to metal Oxides and hydroxides. (D) On the other hand, factories aiming at surface treatment of stainless steel generally have a treatment bath using a nitric acid bath at the same time, and the function of the bath is lost due to the dissolution of metal in the bath. , Must be disposed of. By the way, the bath solution contains divalent iron, and in particular, nitric acid oxidized iron has a strong reducing power, so that hexavalent chromium can be efficiently reduced to reduce toxicity first, and furthermore, chromium hydroxide It has a function to separate it as an object.
【００１２】また、その他の硝酸酸浴を用いた電解剥離
操作のために利用された酸浴と洗浄水に含まれる排液
も、有効に作用する。また、還元処理を完了した処理液
には、まだ遊離酸が残留するために金属イオンが溶解し
ており、さらにアルカリ剤を添加することで不溶解性に
して金属水酸化物を分離することができる。The acid bath used for the electrolytic stripping operation using the other nitric acid bath and the drainage contained in the washing water also work effectively. Further, in the treatment liquid after the completion of the reduction treatment, the metal ions are dissolved because the free acid still remains, and it is possible to separate the metal hydroxide by making it insoluble by adding an alkali agent. it can.
【００１３】この時に使用するアルカリ剤の選択が重要
である。本発明では、溶解塩を電解分離操作で遊離酸と
アルカリに分離できることを利用するが、アルカリ剤に
て金属の水酸化物を生成させる操作で、添加した過剰の
アルカリ剤が不溶解性の化合物を作り、分離された金属
水酸化物側からみると不純物を増やした形態になって、
分離された金属水酸化物の再利用操作を大きく阻害させ
るものとはならない苛性曹達を再利用することで、この
問題を回避することができることになる。At this time, it is important to select an alkaline agent to be used. The present invention utilizes the fact that a dissolved salt can be separated into a free acid and an alkali by an electrolytic separation operation.However, in the operation of generating a metal hydroxide with an alkali agent, an excess of the added alkali agent is an insoluble compound. From the side of the separated metal hydroxide, it becomes a form with increased impurities,
This problem can be avoided by reusing the caustic soda which does not significantly hinder the operation of reusing the separated metal hydroxide.
【００１４】このことで、多量に含まれる価値ある金属
化合物の再利用が可能となり、しかも還元操作、分離操
作に必要な高価な薬剤を処理工程の中で生み出すので、
コストの削減が図られる。This makes it possible to reuse a valuable metal compound contained in a large amount, and to produce expensive chemicals necessary for the reduction operation and the separation operation in the treatment process.
The cost can be reduced.
【００１５】すなわち、まず上記の可溶性金属塩〜クロ
ーム酸曹達の６価クロームにつき、上記(D) 項に示す酸
浴廃棄液を用いて、クロームの無毒化と不溶解性化処理
を施し、さらに溶液中に溶存する塩を分離回収する。That is, first, hexavalent chromium from the above-mentioned soluble metal salt to chromic acid sodium salt is subjected to detoxification and insolubility treatment of chromium using the acid bath waste solution described in the above item (D). The salts dissolved in the solution are separated and collected.
【００１６】溶存塩の遊離酸根とアルカリ根との分離処
理のための装置としては、円筒状の陽極と陰極とを互い
向かい合わせて設置し、その電極間に、イオン選択分離
機能を持つとともに耐酸化性、低電気抵抗性をも持った
イオン交換膜製の分離膜を必要に応じて複数枚設置した
ものが好適である。この分離膜で隔離された陽極室側に
近い膜室に対象アルカリ液が供給され、また対局の陰極
室には、陽極室より電気泳動分離されてきた苛性曹達が
蓄積する。As an apparatus for separating the free acid radical and the alkaline radical of the dissolved salt, a cylindrical anode and a cathode are installed facing each other, and between the electrodes, an ion-selective separation function and an acid-resistant separation are provided. It is preferable that a plurality of separation membranes made of an ion-exchange membrane, which also have chemical resistance and low electrical resistance, are provided as necessary. The target alkali solution is supplied to a membrane chamber close to the anode chamber side isolated by the separation membrane, and caustic soda separated by electrophoresis from the anode chamber accumulates in the opposite cathode chamber.
【００１７】この陰極に苛性曹達が蓄積することで、陽
極室側には、遊離状態の硝酸が生成される。なお、生成
硝酸濃度が低く、再利用に問題が生じる場合には、陽極
室の前の隔膜の前に置いた隔離膜室にサンプルを供給
し、陽極室に硝酸を拡散させることができるように配置
することで、問題を回避することができる。By accumulating caustic soda at the cathode, free nitric acid is generated on the anode chamber side. If the concentration of the produced nitric acid is low and there is a problem in reusing, the sample is supplied to the membrane chamber placed in front of the diaphragm in front of the anode chamber so that nitric acid can be diffused into the anode chamber. By arranging, the problem can be avoided.
【００１８】こうした場合での電解分離作業の電流効率
は高く、各薬剤を購入するのと変らないコストで処理が
できることで、経済的な面でも大きな省資源が可能であ
るといえる。In such a case, the current efficiency of the electrolytic separation work is high, and the treatment can be carried out at the same cost as the purchase of each chemical, so that it can be said that great resource saving is possible in terms of economy.
【００１９】[0019]
【実施例】(1) 図示の酸洗処理槽１において、ステンレ
ス鋼の酸洗処理に使用した硝酸浴液（2.3N硝酸、0.57N
鉄 (この内70％が3 価であった))２を排酸浴液槽３に貯
溜した。 (2) 他方、ソルト処理槽４の塩５の組成は、重量比で硝
酸曹達: 苛性曹達＝7:3とし、その固形粉末を400 〜600
℃の温度に上昇させて均一な溶液とした。ソルト処理
槽４の塩５中にSUS304ステンレス鋼材６を浸漬したの
ち、この鋼材６を急冷槽７内の冷却液８に浸漬して急冷
し、スケールをポーラスな状態として後酸洗処理におけ
る脱スケールを効果的に行えるようにした。Example (1) In the illustrated pickling tank 1, a nitric acid bath solution (2.3N nitric acid, 0.57N
Iron (70% of which was trivalent) 2 was stored in an acid bath 3. (2) On the other hand, the composition of the salt 5 in the salt treatment tank 4 is such that the weight ratio of nitrate: caustic soda = 7: 3 and the solid powder is 400-600.
The temperature was raised to a uniform solution. After immersing the SUS304 stainless steel material 6 in the salt 5 of the salt treatment tank 4, the steel material 6 is immersed in the cooling liquid 8 in the quenching tank 7 and quenched, and the scale is made porous to remove the scale in the post-pickling treatment. Can be performed effectively.
【００２０】この急冷冷却液８の組成は時間とともに変
化するが、硝酸根は50gr/l、Na塩は34 gr/l であり、ま
たCr6+が2000ppm 溶存し、同時に鉄のヒドロリュウム分
散物5000ppm が共存し、液のpHは約13と強アルカリ性を
示す値になった。 (3) 次いで急冷後のステンレス鋼６を中和処理槽９に浸
漬し、その中和処理槽９には、上述の排酸浴液槽３に貯
溜した酸浴液２を用いて中和処理をした。 (4) この際の中和処理は、従来の水を使用した中和処理
に比べ同等以上に良好に行うことが可能であり、スケー
ルの多孔中にアルカリが存在していないものとすること
が可能となった。The composition of the quenching cooling liquid 8 changes with time, but the nitrate content is 50 gr / l, the Na salt content is 34 gr / l, Cr 6+ is dissolved in 2000 ppm, and at the same time, 5000 ppm coexisted, and the pH of the solution was about 13, which was a value indicating strong alkalinity. (3) Next, the quenched stainless steel 6 is immersed in the neutralization tank 9, and the neutralization tank 9 is subjected to the neutralization treatment using the acid bath solution 2 stored in the above-described acid bath bath 3. Did. (4) The neutralization treatment at this time can be performed as well as or better than the conventional neutralization treatment using water, and the alkali should not be present in the pores of the scale. It has become possible.
【００２１】また、この中和処理槽９より溢れる液10
は、急冷槽７への供給水とした。この液10には、可溶性
の硝酸曹達、苛性曹達を多量に含み、金属水酸化物も多
量に共存していた。 (5) 次に、溢れる液に含有される薬剤を回収すべき操作
に入るために、これら液10を貯溜槽11に貯溜した。The liquid 10 overflowing from the neutralization tank 9
Is water supplied to the quenching tank 7. This liquid 10 contained a large amount of soluble nitrate and caustic soda, and a large amount of metal hydroxide was also present. (5) Next, these liquids 10 were stored in the storage tank 11 in order to start an operation for recovering the drug contained in the overflowing liquids.
【００２２】さらにソルト浴の底部に堆積する不溶解性
金属酸化物や硅砂などの異物12を取り出し、これを洗浄
して、付着した塩と同時に共存するクローム化合物の飛
散を防止し、その洗浄水13をも貯留槽11に流入させて貯
留した。Further, foreign matters 12 such as insoluble metal oxides and silica sand deposited on the bottom of the salt bath are taken out and washed to prevent the chromium compound coexisting simultaneously with the attached salt from being scattered. 13 was also flowed into the storage tank 11 and stored.
【００２３】この貯留槽11の貯溜液を前記の排酸浴液で
まず中和すると同時に、酸性下での酸浴に残留する活性
な３価鉄の添加でクロームを還元させた。この様子は、
反応槽に浸漬した酸化還元電位の測定装置で監視した。
かつ、反応槽液の温度を40〜50℃以上に維持しすること
で、処理の完全を期すことができた。The liquid stored in the storage tank 11 was first neutralized with the above-mentioned waste acid bath solution, and at the same time, chromium was reduced by adding active trivalent iron remaining in the acid bath under acidic conditions. This situation is
The oxidation-reduction potential was immersed in the reaction tank and monitored by a measuring device.
In addition, by maintaining the temperature of the reaction tank solution at 40 to 50 ° C. or higher, complete treatment could be expected.
【００２４】還元処理を終えた液は、再度アルカリ剤の
添加で溶存金属イオンを不溶解化し、これらの分散物を
除去する中和・還元分散物分離器14にて分散物15を分離
した後、清浄濾過液16を得て、これを貯留槽17に貯留し
た。 (6) この貯留された清浄濾過液16をイオン交換膜を隔膜
とする電解分離槽18に供給し、陽極室側の循環槽19の循
環塩液20を電解操作することにより、回収遊離酸液21を
回収するとともに、陰極室側の循環槽22の循環塩液23よ
りアルカリ性苛性曹達24を分離して回収することが可能
であった。 (7) 回収された遊離酸は2.5N硝酸であり、再度酸浴に転
用することが可能であった。The liquid after the reduction treatment is again made insoluble by dissolving the dissolved metal ions by adding an alkali agent, and the dispersion 15 is separated by a neutralization / reduction dispersion separator 14 for removing these dispersions. Then, a clean filtrate 16 was obtained and stored in the storage tank 17. (6) The stored clean filtrate 16 is supplied to an electrolytic separation tank 18 having an ion-exchange membrane as a membrane, and the circulating salt solution 20 in a circulating tank 19 on the anode chamber side is subjected to an electrolytic operation to recover the recovered free acid solution. It was possible to separate and recover the alkaline caustic soda 24 from the circulating salt solution 23 in the circulating tank 22 on the cathode chamber side while collecting 21. (7) The recovered free acid was 2.5N nitric acid, which could be converted to an acid bath again.
【００２５】さらにアルカリ液は2.7Nであり、これは還
元処理を施した液の中和にも再利用された。Further, the alkaline solution was 2.7 N, which was reused for neutralizing the solution subjected to the reduction treatment.
【００２６】[0026]
【発明の効果】以上説明したようにこの発明によると、
ステンレス鋼のソルト処理に伴い発生する濃厚硝酸曹達
を排液として系外に排出せずに回収し, 再度酸浴組成と
して利用することができ、さらに高温ソルト処理ではそ
の発生を抑制し難いい６価クロームの3 価への転換手段
と、液系よりの不溶性分離作業のための薬剤とを、同じ
排液を用いることで、その排液に含まれる薬剤をも同時
に回収でき、このため薬剤資源の削減と有価薬剤の回収
と可溶性窒素源の削減に伴う環境の浄化作用とを合わせ
て達成でき、その効果は多大である。As described above, according to the present invention,
The concentrated nitric acid generated during the salt treatment of stainless steel can be collected as a drainage solution without being discharged out of the system, and can be reused as the acid bath composition. By using the same effluent for the means for converting trivalent chromium to trivalent chromium and the agent for the insoluble separation work from the liquid system, the drug contained in the effluent can be recovered at the same time. It is possible to achieve a combination of the reduction of wastewater, the recovery of valuable chemicals and the purification of the environment accompanying the reduction of the soluble nitrogen source, and the effect is enormous.
【図１】この発明の方法の一実施例の説明図である。FIG. 1 is an explanatory view of one embodiment of the method of the present invention.
１ 酸洗処理槽 ４ ソルト処理槽 ７ 急冷槽 ９ 中和処理槽 10 液 11 貯留槽 13 洗浄水 14 中和・還元分散物分離器 18 電解分解槽 21 回収遊離酸液 24 アルカリ性苛性曹達 1 Pickling tank 4 Salt processing tank 7 Quenching tank 9 Neutralization tank 10 Liquid 11 Storage tank 13 Washing water 14 Neutralizing / reducing dispersion separator 18 Electrolytic decomposition tank 21 Collected free acid solution 24 Alkaline caustic soda
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) C23G 1/32 C23G 1/36 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. 7 , DB name) C23G 1/32 C23G 1/36
Claims (2)
た塩浴を用いて鋼材の表面処理を施すに際し、高温溶融
炉に浸漬されて取り出された後の鋼材を水中に浸漬して
冷却を行うことで発生する溢れ液と、この冷却処理を終
えた鋼材に付着したアルカリ剤を中和することで発生す
る溢れ液と, 前記塩浴の底に堆積しかつ取り出された鋼
滓に付着した塩浴組成物の除去のための洗浄時に発生す
る洗浄液とに含まれる組成薬剤を回収するために、処理
鋼材組成中のクローム金属化合物が塩浴中で６価の水溶
性塩に変化して溶存している前記各溶液の混合液中のこ
れら化合物を、還元化後に不溶性水酸化物処理し、この
処理のための薬剤として、前記鋼材を浸漬酸洗い処理す
るための少なくとも硝酸を含む浴に溶解する金属イオン
を含有し、かつ遊離酸を残す酸液の一部を、前記混合液
の還元剤として、その中和操作後の液に注入し、この還
元反応の環境を高温かつ酸性を維持したものとして、処
理対象液に含まれている６価の塩を３価に還元させ、そ
の後、苛性曹達でアルカリ性にすることで、溶解金属物
を、不溶解アルカリ剤の混入なしに、不溶解性金属水酸
化固形物と、可溶性硝酸曹達や苛性曹達などの可溶性塩
液とに分離することを特徴とする塩浴液の処理方法。When a steel material is subjected to a surface treatment using a salt bath having a composition of a nitrate compound or caustic soda, the steel material taken out by being immersed in a high-temperature melting furnace is cooled by being immersed in water. And the overflow generated by neutralizing the alkaline agent attached to the steel material after the cooling treatment, and the salt bath deposited on the bottom of the salt bath and attached to the removed steel slag. The chromium metal compound in the treated steel composition changes into a hexavalent water-soluble salt in a salt bath and is dissolved in order to recover the composition chemical contained in the cleaning liquid generated during the cleaning for removing the composition. These compounds in a mixture of the above solutions are treated with an insoluble hydroxide after reduction, and as a chemical for this treatment, a metal dissolved in a bath containing at least nitric acid for immersing and pickling the steel material. Contains ions and is free A part of the acid solution which remains is injected into the solution after the neutralization operation as a reducing agent of the mixed solution, and the environment of the reduction reaction is maintained at a high temperature and acidic, and is contained in the solution to be treated. The dissolved hexavalent salt is reduced to trivalent and then alkalized with caustic soda, so that the dissolved metal material can be insoluble metal hydroxide solids and soluble nitric acid sodium salt without mixing insoluble alkali agent. A method for treating a salt bath, wherein the salt bath is separated into a soluble salt solution such as sodium hydroxide and caustic soda.
価物としての遊離酸とアルカリ剤として再度回収するに
際し、円筒状の陽、陰両電極間に陽イオン交換膜をイオ
ン選択分離隔膜として同心状に設置した電解槽に供給
し、かつ両電極間に印荷荷電を供給して、陽極電極室に
近い隔離室より遊離硝酸を回収するとともに、陰極電極
室側より苛性曹達の溶液を回収して鋼材の処理工程に再
度利用することを特徴とする請求項１記載の塩浴液の処
理方法。2. When the chloride contained in the treated solution is recovered again as a free acid and an alkaline agent as valuables, a cation exchange membrane is provided between the cylindrical positive and negative electrodes by an ion selective separation membrane. As well as supplying condensed charge between both electrodes, recovering free nitric acid from the isolation chamber near the anode electrode chamber, and removing the solution of caustic soda from the cathode electrode chamber side. The method for treating a salt bath according to claim 1, wherein the salt bath is collected and reused in a process for treating a steel material.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03068649A JP3100410B2 (en) | 1991-04-02 | 1991-04-02 | Salt bath treatment method |
| DE69117927T DE69117927T2 (en) | 1991-04-02 | 1991-12-23 | Process for treating a molten salt bath |
| US07/812,627 US5348628A (en) | 1991-04-02 | 1991-12-23 | Method of treating salt bath liquid |
| EP91122202A EP0507006B1 (en) | 1991-04-02 | 1991-12-23 | Method of treating salt bath liquid |
| CA002058526A CA2058526A1 (en) | 1991-04-02 | 1991-12-24 | Method of treating salt bath liquid |
| KR1019910024115A KR920019969A (en) | 1991-04-02 | 1991-12-24 | Treatment method of salt bath |
| US08/274,903 US5496449A (en) | 1991-04-02 | 1994-07-14 | Method of treating salt bath liquid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03068649A JP3100410B2 (en) | 1991-04-02 | 1991-04-02 | Salt bath treatment method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04304393A JPH04304393A (en) | 1992-10-27 |
| JP3100410B2 true JP3100410B2 (en) | 2000-10-16 |
Family
ID=13379764
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03068649A Expired - Fee Related JP3100410B2 (en) | 1991-04-02 | 1991-04-02 | Salt bath treatment method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3100410B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0762575A (en) * | 1993-08-27 | 1995-03-07 | Unitika Ltd | Purifying equipment and purifying method for bath liquid |
| CN109563631A (en) * | 2016-09-27 | 2019-04-02 | Posco公司 | Uniform treatment device and acid dip pickle |
-
1991
- 1991-04-02 JP JP03068649A patent/JP3100410B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04304393A (en) | 1992-10-27 |
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