JPS5846554B2 - How to protect an electrolytic cell - Google Patents
How to protect an electrolytic cellInfo
- Publication number
- JPS5846554B2 JPS5846554B2 JP4291782A JP4291782A JPS5846554B2 JP S5846554 B2 JPS5846554 B2 JP S5846554B2 JP 4291782 A JP4291782 A JP 4291782A JP 4291782 A JP4291782 A JP 4291782A JP S5846554 B2 JPS5846554 B2 JP S5846554B2
- Authority
- JP
- Japan
- Prior art keywords
- electrolysis
- electrolytic cell
- electrolytic
- current
- stopped
- 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
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/34—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis
- C25B1/46—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis in diaphragm cells
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
Description
【発明の詳細な説明】
本発明はイオン交換膜法によるアルカリ金属塩水溶液の
電解に関し、詳しくは電解停止時における電解槽の保護
方法を提供するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the electrolysis of an aqueous alkali metal salt solution by an ion exchange membrane method, and specifically provides a method for protecting an electrolytic cell when electrolysis is stopped.
アルカリ金属塩水溶液の電解方法としては、般に水銀法
と隔膜法が工業的に行われてきたが水銀法は公害上の問
題、また隔膜法では高エネルギーを要し取得されるアル
カリ金属水酸化物製品も不純である欠陥を有している。The mercury method and the diaphragm method have generally been used industrially to electrolyze aqueous solutions of alkali metal salts, but the mercury method poses pollution problems, and the diaphragm method requires high energy to obtain alkali metal hydroxide. Goods also have defects that are impure.
したがって、第三の技術としてイオン交換膜法が開発さ
れているが、化学的にデリケートなイオン交換膜を用い
ることもあり高純度、高濃度のアルカリ金属水酸化物を
高電流効率で取得することに種々苦慮されている。Therefore, the ion-exchange membrane method has been developed as a third technology, but it sometimes uses a chemically delicate ion-exchange membrane, making it difficult to obtain high-purity, high-concentration alkali metal hydroxides with high current efficiency. There are various concerns faced.
その１つとして、イオン交換膜法によるアルカリ金属塩
水溶液の電解において、休転時に電解を一旦停止した後
に再開した場合には電圧の上昇ばかりでなく電流効率が
著しく低下する現象がみられることである。One such problem is that in the electrolysis of aqueous alkali metal salt solutions using the ion-exchange membrane method, when electrolysis is restarted after it has been stopped, there is a phenomenon in which not only the voltage increases but also the current efficiency decreases significantly. be.
これらの現象はイオン交換膜の汚染に主として基因する
ものと推測されるが、特に電解の停止時にどのような機
構で生起するのか明確でない。It is assumed that these phenomena are mainly caused by contamination of the ion exchange membrane, but it is not clear what mechanism causes them, especially when electrolysis is stopped.
即ち、これらの現象は通常の電解通電中には殆んど認め
られないのに対して、電解電流の停止時に現れ、しかも
一旦このような現象が生起すると通電しながら酸洗いし
ても全く回復できないのが大きな暗照である。In other words, while these phenomena are hardly observed during normal electrolytic energization, they appear when the electrolytic current is stopped, and once these phenomena occur, they do not recover at all even if pickled while energizing. What I can't do is a big dark light.
本発明者らは上記した電解の停止に伴う問題について種
々検討した結果、電解の停止時に微少電流を通ずること
によってイオン交換膜の汚染が防止され、電解を再開し
ても電圧の上昇がなく電流効率の低下もない知見を得て
本発明を完成したものである。As a result of various studies by the present inventors on the problems associated with stopping electrolysis, we found that contamination of the ion exchange membrane is prevented by passing a small current when electrolysis is stopped, and even when electrolysis is restarted, there is no increase in voltage and the current The present invention was completed based on the knowledge that there was no decrease in efficiency.
即ち本発明はイオン交換膜法によるアルカリ金属塩水溶
液の電解において、電解の停止期間中を通じて電解槽内
に１０ ｍＡ ／ ｒｒｌ〜該アルカリ金属塩水溶液の
分解電圧未満の微少電流を通じることを特徴とする電解
槽の保護方法である。That is, the present invention is characterized in that in the electrolysis of an aqueous alkali metal salt solution using an ion exchange membrane method, a minute current of 10 mA/rrl to less than the decomposition voltage of the aqueous alkali metal salt solution is passed through the electrolytic cell during the stop period of electrolysis. This is a method of protecting electrolytic cells.
本発明は電解槽の陽極室および陰極室に電解液を十分に
入れて電解の停止と同時に且つ停止期間中を通じて微少
電流を通じてやればよい。In the present invention, it is sufficient to fill the anode chamber and the cathode chamber of the electrolytic cell with a sufficient amount of electrolyte, and to apply a small current at the same time as the electrolysis is stopped and throughout the period when the electrolysis is stopped.
この停止期間中を通じて電解槽に通じる電流は１０ｍＡ
／ｄ以上されば電解するアルカリ金属塩水溶液の電解電
圧未満の電流までよいが、一般には１０〜１０００ ｍ
Ａ／ｒｒｉ’好ましくは５０〜５００ｒｒＩＡ／Ｒの微
少電流で十分である。The current flowing through the electrolytic cell during this stop period is 10 mA.
/d or more, the current may be lower than the electrolytic voltage of the aqueous alkali metal salt solution to be electrolyzed, but generally it is 10 to 1000 m
A/rr', preferably a minute current of 50 to 500 rrIA/R is sufficient.
なお、一般の工業用整流器では１０００〜１０，０００
Ａ／７ｒｉ：の電解電流から数１００ｍＡ／ｍ″微少電
流まで落すことは非常に困難であるから、適宜に可能な
回路を含む整流器を使用することが好都合である。In addition, for general industrial rectifiers, it is 1000 to 10,000
Since it is very difficult to reduce the electrolytic current from A/7ri: to a minute current of several 100 mA/m'', it is convenient to use a rectifier including a suitable circuit.
勿論上記停止期間中と言う意味は電解再開後の重臣およ
び電流効率が停止前のそれに影響を与えない程度の短時
間の通電の中断を排除するものではない。Of course, the meaning of "during the stop period" does not exclude interruption of current flow for a short time such that the current efficiency after restarting electrolysis does not affect that before the stop.
上記したように、本発明においては停止時の電解槽に微
少電流を通じることが重要で、イオン交換膜の汚染が防
止され護膜の耐性が長時間に維持できるばかりでなく、
電解を再開しても停止前の重臣および電流効率を維持で
きる効果がある。As mentioned above, in the present invention, it is important to pass a minute current through the electrolytic cell when it is stopped, which not only prevents contamination of the ion exchange membrane and maintains the durability of the protective membrane for a long time.
Even if electrolysis is restarted, it has the effect of maintaining the same level of efficiency and current efficiency as before it was stopped.
本発明は特に陰極として鉄または鉄合金等の金属電極を
用いて、イオン交換膜として例えばＮａｆ−ｉｏｎ （
ｄｕ ｐｏｎｔ社製）等の弗素系陽イオン交換膜を配し
た２室電解槽あるいは炭化水素系陽イオン交換膜と他の
保護膜とから構成した３室電解槽に適用される。In particular, the present invention uses a metal electrode such as iron or an iron alloy as a cathode, and uses, for example, Naf-ion (
It can be applied to a two-chamber electrolytic cell equipped with a fluorine-based cation exchange membrane (manufactured by Du Pont) or a three-chamber electrolytic cell configured with a hydrocarbon-based cation exchange membrane and another protective membrane.
実施例 １
縦１ｍ、横１ｍのラス材金属陽極と鉄製のラス材陰極と
からなるＢｉｐｏｌａｒ電極にＮａｆ ｉｏｎ ３１５
（ｄｕ ｐｏｎｔ社製、陽イオン交換膜）を配して１０
対のＢｉｐｏｌａｒ電槽を２槽（Ａ、Ｂ）を構成した。Example 1 Nafion 315 was used as a bipolar electrode consisting of a lath metal anode and an iron lath cathode measuring 1 m long and 1 m wide.
(manufactured by du Pont, cation exchange membrane)
A pair of Bipolar batteries constituted two tanks (A, B).
この小電槽とＢ電槽を用いて、それぞれ第１表の条件で
食塩水の電解を３ケ月運転した。Using this small container and container B, electrolysis of saline water was operated for three months under the conditions shown in Table 1, respectively.
第１表
陽極液： ＮａＣｌ２５０ ’Ｊ／ｌ
ｐＨ±１
電流密度： ３０Ａ／ｄｉ
電解温度： ８０℃
陰極液： ＮａＯＨ２０％
次いで、各電解槽をそれぞれ次の方法で１週間伴走した
。Table 1 Anolyte: NaCl 250'J/l pH±1 Current density: 30 A/di Electrolysis temperature: 80° C. Catholyte: NaOH 20% Next, each electrolytic cell was run for one week in the following manner.
即ち、Ａ電解槽では陽極室中の有効塩素が無くなる時間
だけアルカリ性塩水を陽極室に流した後に停止した。That is, in the A electrolytic cell, alkaline salt water was allowed to flow into the anode chamber for a period of time until the available chlorine in the anode chamber was exhausted, and then the electrolytic cell was stopped.
Ｂ電解槽では電流値を１００Ａ／ｌから直ちに１００ｍ
Ａ／ｍ”に落して陽極室中の有効塩素が無くなるまでア
ルカリ性塩水を流した。In the B electrolytic tank, the current value is changed from 100 A/l to 100 m immediately.
A/m'' and alkaline salt water was flowed until there was no available chlorine in the anode chamber.
上記の各電解槽を１週間の停止後に再度第１表と同様の
条件で運転した。Each of the electrolytic cells described above was operated again under the same conditions as in Table 1 after being stopped for one week.
その結果、停止の前後における電解性能の比較を第２表
に示す。As a result, Table 2 shows a comparison of the electrolytic performance before and after stopping.
Ａ電解槽では停Ｌｌ：、＠後において電解性能の低下が
みられるのに対して、Ｂ電解槽では電解性能の低下は殆
んど認められない。In the A electrolytic cell, a decrease in electrolytic performance is observed after the stop Ll:,@, whereas in the B electrolytic cell, almost no deterioration in the electrolytic performance is observed.
なお、表中の電流効率は生成苛性が基準であり、電Ｅ／
対とともに平均値である。Note that the current efficiency in the table is based on the generated causticity, and the electric current efficiency is based on the generated causticity.
The average value along with the pair.
以下同じである。また、上記の再運転２週間後に各電解
槽における膜を取り出して、その状態と物性を調べた結
果を第３表に示す。The same applies below. Furthermore, after two weeks of restarting, the membranes in each electrolytic cell were taken out and their condition and physical properties were investigated. Table 3 shows the results.
なお、表中の膜抵抗は５Ｎ−ＮａＣｌ／膜／６Ｎ−Ｎａ
ＯＨ系で１０００サイクル交流ブリッジで測定した。In addition, the membrane resistance in the table is 5N-NaCl/membrane/6N-Na
Measurement was performed using an OH system with a 1000 cycle AC bridge.
実施例 ２
実施例１と同一の電解槽で、１０対のＢｉｐｏｌａｒ電
極間に１０枚のＮａｆ １ｏｒｌ 改質の陽イオン交
換膜を配し３つの電槽（Ａ、Ｂ、Ｃ）電槽を構成し、こ
れらをシリーズに接続して第４表に示す条件で食塩水の
電解を行った。Example 2 In the same electrolytic cell as in Example 1, 10 Naf 1orl modified cation exchange membranes were arranged between 10 pairs of Bipolar electrodes to form three cells (A, B, C). These were connected in series and electrolysis of saline water was carried out under the conditions shown in Table 4.
陽極液：
電流密度：
電解温度：
陰極液：
第４表
ＮａＣＡ ２００９／ｌ
ｐＨ÷３
３０Ａ／ｄｉ
８０°Ｃ
ＮａＯＨ２５％
６ケ月運転後に３電槽とも１ケ月間停止したが、各電槽
について第５表に示す条件下に停止した。Anolyte: Current density: Electrolysis temperature: Cathode: Table 4 NaCA 2009/l pH ÷ 3 30A/di 80°C NaOH 25% After 6 months of operation, all three batteries were stopped for one month, but the It was stopped under the conditions shown in Table 5.
１ケ月の停止後に運転を第４表と同一条件で再開した。After one month of suspension, operation was resumed under the same conditions as in Table 4.
上記の停止前と停止後における電解性能の比較を第６表
Ｉこ示す。A comparison of the electrolytic performance before and after the above-mentioned stop is shown in Table 6.
実施例 ３
縦１ｍ、横０．５ｍのラス材金属陽極と鉄製金鋼（Ｒｏ
ｓｉｅｒ社製）の陰極とを備えた１０対の１３ｉｐｏｌ
ａｒ電極間に１０枚の炭化水素−カルボン酸系陽イオン
交換膜とアスベストを弗素樹脂で補強して製造した中性
多孔質膜とを配して三基電解槽を３槽（Ａ、Ｂ、Ｃ）を
構成した。Example 3 A lath metal anode with a length of 1 m and a width of 0.5 m and a steel metal anode (Ro
10 pairs of 13ipol cathodes (manufactured by Sier)
Three three-unit electrolytic cells (A, B, C) was constructed.
上記の各電解槽を用いて、第７表に示す条件下に食塩水
の電解を行った。Using each of the above electrolytic cells, electrolysis of saline water was performed under the conditions shown in Table 7.
陽極液：
電流密度 ：
電解温度 ：
陰極液：
第７表
ＮａＣ，ｅ ２６０’ｌ／１
ｐＨｆ：１
３０Ａ／ｄ〆
８０°Ｃ
ＮａＯＨ３０％
３ケ月運転後に各電槽について第８表に示す条件下ｌこ
停止し１０日間放置した。Anolyte: Current density: Electrolysis temperature: Cathode: Table 7 NaC,e 260'l/1 pHf: 1 30A/d〆80°C NaOH30% After 3 months of operation, each battery case was tested under the conditions shown in Table 8 It was stopped and left for 10 days.
次いで１０日間の停止後に運転を第７表と同一条件で再
開した。Then, after a 10-day suspension, operation was resumed under the same conditions as in Table 7.
上記の停止前と停止後における電解性能の比較を第９表
に示す。Table 9 shows a comparison of the electrolytic performance before and after the above stop.
なお、Ｃ電槽における膜は電解再開後２０ＢＩこ鉄錆び
の付着部に小孔があき使用不可能になった。In addition, after restarting electrolysis, the membrane in C tank became unusable due to small holes in the part where the iron rust had adhered.
Claims (1)
において、電解の停止期間中を通じて電解槽内に１０
ｍＡ７’ｒｒｊ〜該アルカリ金属塩水溶液の分解電圧未
満の微少電流を通じることを特徴とする電解槽の保護方
法。1. In the electrolysis of aqueous alkali metal salt solutions using the ion exchange membrane method, 10
mA7'rrj~A method for protecting an electrolytic cell, characterized by passing a minute current lower than the decomposition voltage of the aqueous alkali metal salt solution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4291782A JPS5846554B2 (en) | 1982-03-19 | 1982-03-19 | How to protect an electrolytic cell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4291782A JPS5846554B2 (en) | 1982-03-19 | 1982-03-19 | How to protect an electrolytic cell |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6607076A Division JPS52149295A (en) | 1976-06-08 | 1976-06-08 | Protecting method for electrolytic bath |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57169096A JPS57169096A (en) | 1982-10-18 |
| JPS5846554B2 true JPS5846554B2 (en) | 1983-10-17 |
Family
ID=12649365
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4291782A Expired JPS5846554B2 (en) | 1982-03-19 | 1982-03-19 | How to protect an electrolytic cell |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5846554B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4561949A (en) * | 1983-08-29 | 1985-12-31 | Olin Corporation | Apparatus and method for preventing activity loss from electrodes during shutdown |
| JP3408462B2 (en) * | 1999-07-14 | 2003-05-19 | 東亞合成株式会社 | Method for protecting gas diffusion cathode in alkaline chloride electrolytic cell |
-
1982
- 1982-03-19 JP JP4291782A patent/JPS5846554B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57169096A (en) | 1982-10-18 |
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