JPH0527712B2 - - Google Patents
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- Publication number
- JPH0527712B2 JPH0527712B2 JP16835287A JP16835287A JPH0527712B2 JP H0527712 B2 JPH0527712 B2 JP H0527712B2 JP 16835287 A JP16835287 A JP 16835287A JP 16835287 A JP16835287 A JP 16835287A JP H0527712 B2 JPH0527712 B2 JP H0527712B2
- Authority
- JP
- Japan
- Prior art keywords
- cathode
- hydrogen overvoltage
- low hydrogen
- platinum group
- alkali metal
- 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 - Lifetime
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- Electrodes For Compound Or Non-Metal Manufacture (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
Description
【発明の詳細な説明】
「産業上の利用分野」
本発明は、ハロゲン化アルカリ金属水溶液又は
水酸化アルカリ金属水溶液の電気分解で使用する
低水素過電圧陰極が劣化した際に、性能を回復す
る方法に関する。Detailed Description of the Invention "Field of Industrial Application" The present invention provides a method for restoring the performance of a low hydrogen overvoltage cathode used in the electrolysis of an aqueous alkali metal halide solution or an aqueous alkali metal hydroxide solution when the cathode deteriorates. Regarding.
「従来技術と問題点」
ハロゲン化アルカリ金属水溶液又は水酸化アル
カリ金属水溶液の電気分解に使用する陰極として
は、従来軟鉄が主に使用されていたが、軟鉄は水
素過電圧が高いため、水素過電圧の低い陰極が
種々提案されている。低水素過電圧陰極は、陰極
芯体上にニツケル、コバルトもしくは白金族元素
の単体もしくは混合物又はそれら合金の金属もし
くは酸化物等を分散メツキ法、電気メツキ法、無
電解メツキ法、溶射法、浸漬法、溶接法等で低水
素過電圧コーテイング層として取り付けたものが
一般に用いられている。"Prior art and problems" Conventionally, soft iron has been mainly used as a cathode for electrolysis of aqueous alkali metal halides or alkali metal hydroxide solutions, but soft iron has a high hydrogen overvoltage. Various low cathodes have been proposed. Low hydrogen overvoltage cathodes can be produced using a plating method, an electroplating method, an electroless plating method, a thermal spraying method, or a dipping method in which nickel, cobalt, or a mixture of platinum group elements or metals or oxides of these alloys are dispersed on a cathode core. A low hydrogen overvoltage coating layer attached by welding or the like is generally used.
ところで、低水素過電圧陰極は種々の原因で劣
化し、水素過電圧が上昇することが知られてい
る。例えば、陰極の表面に水銀、鉛、鉄等の水素
過電圧が高い物質が付着又は電着するとか、陰極
活性部が金属であればセル停止又は解体時等にお
ける酸化により、また、金属酸化物であれば還元
により活性点を失うとか、活性部が内部応力又は
ガス等によるエロージヨン、コロージヨンを受
け、裂け目が入るとかの場合である。従来、この
ような原因で劣化した陰極の活性を回復する方法
はなく、セルを停止して陰極を分解し、低水素過
電圧処理を再び行うというのが常法であつた。 By the way, it is known that a low hydrogen overvoltage cathode deteriorates due to various causes and the hydrogen overvoltage increases. For example, substances with high hydrogen overvoltage such as mercury, lead, and iron may adhere or electrodeposit on the cathode surface, or if the cathode active part is metal, it may be oxidized when the cell is stopped or dismantled, or metal oxides may If so, active sites may be lost due to reduction, or cracks may occur in active areas due to erosion or corrosion due to internal stress or gas. Conventionally, there has been no method to restore the activity of the cathode that has deteriorated due to such causes, and the usual method has been to stop the cell, decompose the cathode, and perform the low hydrogen overvoltage treatment again.
「問題点を解決するための手段」
本発明者らはかかる実情に鑑み、劣化した低水
素過電圧陰極をセルから取り外すことなく活性を
回復させる方法を鋭意研究した結果本発明に到達
したものである。"Means for Solving the Problem" In view of the above circumstances, the inventors of the present invention have arrived at the present invention as a result of intensive research into a method for restoring the activity of a degraded low hydrogen overvoltage cathode without removing it from the cell. .
即ち、本発明はハロゲン化アルカリ金属水溶液
又は水酸化アルカリ金属水溶液の電気分解に使用
する低水素過電圧陰極が劣化した場合において、
該低水素過電圧陰極をセルから取り外すことな
く、陰極室内に可溶性白金族化合物を添加するこ
とを特徴とする劣化した低水素過電圧陰極の活性
回復方法を内容とするものである。 That is, the present invention provides a method for reducing hydrogen overvoltage when a low hydrogen overvoltage cathode used for electrolysis of an aqueous alkali metal halide solution or an aqueous alkali metal hydroxide solution deteriorates.
The subject matter is a method for restoring the activity of a deteriorated low hydrogen overvoltage cathode, which is characterized by adding a soluble platinum group compound into the cathode chamber without removing the low hydrogen overvoltage cathode from the cell.
電解中の低水素過電圧陰極はその表面において
最も活発に電解反応が行われており、電流密度が
高くなる程、コーテイング層の表面から深い位置
まで陰極として作用している。そして陰極として
作用している表面が酸化又は高水素過電圧物質の
付着により劣化すると水素過電圧が上昇するとの
知見を得た。 Low hydrogen overvoltage during electrolysis The cathode undergoes the most active electrolytic reaction on its surface, and the higher the current density, the deeper the coating layer acts as a cathode from the surface. We have also found that when the surface acting as a cathode deteriorates due to oxidation or adhesion of high hydrogen overvoltage substances, the hydrogen overvoltage increases.
そして、劣化している低水素過電圧陰極の表面
は発生期の水素による還元性が高くなつており、
陰極室に低水素過電圧の金属イオンを添加すれば
選択的に該陰極の表面に付着し、水素過電圧が下
がるとの知見に基づき、本発明が完成された。 The surface of the degraded low hydrogen overvoltage cathode is highly reducible to hydrogen during its nascent stage.
The present invention was completed based on the knowledge that if metal ions with a low hydrogen overvoltage are added to the cathode chamber, they will selectively adhere to the surface of the cathode, thereby lowering the hydrogen overvoltage.
陰極室に添加する可溶性白金族化合物は、水又
は水酸化アルカリ金属水溶液に可溶な白金族化合
物であれば何でもよく、特に限定されない。可溶
性白金族化合物の例としては、塩化パラジウム、
臭化パラジウム、硝酸パラジウム、過塩素酸ロジ
ウム、硝酸ロジウム、硫酸ロジウム、三塩化ロジ
ウム、三臭化ロジウム、三塩化イリジウム、三臭
化イリジウム、三塩化ルテニウム、三臭化ルテニ
ウム、ルテニウム酸カリウム、四塩化オスミウ
ム、オスミウム酸カリウム、ヘキサフルオロ白金
酸塩、テトラクロロ白金酸塩、ヘキサヒドロキソ
白金酸塩、ビスオキサラト白金酸塩、ヘキサアン
ミン白金酸塩、ジクロロジアンミン白金、テトラ
クロロジアンミン白金、ビスグリシナト白金、ジ
クロロビス（エチレンジアミン）白金塩、ジアン
ミンジニトロ白金、テトラニトロ白金酸塩、テト
ラクロロパラジウム酸塩、ヘキサクロロパラジウ
ム酸塩、テトラアンミンパラジウム塩、ジクロロ
エチレンジアミンパラジウム、ジアンミンジニト
ロパラジウム、ヘキサフルオロロジウム酸塩、ヘ
キサアンミンロジウム塩、クロロペンタアンミン
ロジウム塩、ヒドリドペンタアンミンロジウム硫
酸塩、ジクロロビス（エチレンジアミン）ロジウ
ム塩、トリス（オキサラト）ロジウム酸カリウ
ム、ヘキサシアノロジウム酸カリウム、ヘキサク
ロロイリジウム酸塩、ヘキサクロロイリジウム酸
塩、ヘキサアンミンイリジウム塩、クロロペンタ
アンミンイリジウム塩、ペンタアンミンアクアイ
リジウム塩、トリス（２、2′−ビピリジン）ルテ
ニウム塩、μ−オキソ−ビス（ペンタクロロルテ
ニウム）酸カリウム、ヘキサシアノルテニウム酸
塩、ペンタクロロアクアルテニウム酸塩、ペンタ
クロロニトロシルルテニウム酸塩、ヘキサクロロ
オスミウム酸塩、ペンタクロロニトリドオスミウ
ム酸塩等が挙げられる。本発明でいう可溶性と
は、白金族化合物の溶解度が10-6モル／以上の
ものをいう。上記白金族化合物は単独又は２種以
上混合して使用してもよい。 The soluble platinum group compound added to the cathode chamber is not particularly limited and may be any platinum group compound that is soluble in water or an aqueous alkali metal hydroxide solution. Examples of soluble platinum group compounds include palladium chloride,
Palladium bromide, palladium nitrate, rhodium perchlorate, rhodium nitrate, rhodium sulfate, rhodium trichloride, rhodium tribromide, iridium trichloride, iridium tribromide, ruthenium trichloride, ruthenium tribromide, potassium ruthenate, tetrabromide Osmium chloride, potassium osmate, hexafluoroplatinate, tetrachloroplatinate, hexahydroxoplatinate, bisoxalatoplatinate, hexaammineplatinate, dichlorodiammineplatinum, tetrachlorodiammineplatinum, bisglycinate platinum, dichlorobis( Ethylenediamine) platinum salt, diammine dinitroplatinum, tetranitroplatinate, tetrachloropalladate, hexachloropalladate, tetraamminepalladium salt, dichloroethylenediamine palladium, diamminedinitropalladium, hexafluororhodate, hexaamminerhodium salt, chloropenta Ammine rhodium salt, hydridopentaammine rhodium sulfate, dichlorobis(ethylenediamine) rhodium salt, potassium tris(oxalato)rhodate, potassium hexacyanorhodate, hexachloroiridate, hexachloroiridate, hexaammine iridium salt, chloropentaammine iridium salt, pentaamine aqua iridium salt, tris(2,2'-bipyridine) ruthenium salt, μ-oxo-bis(pentachlororuthenate) potassium, hexacyanoruthenate, pentachloroaquarthenate, pentachloronitrosylruthenate salt, hexachloroosmate, pentachloronitride osmate, and the like. Solubility as used in the present invention means that the solubility of the platinum group compound is 10 -6 mol/or more. The above platinum group compounds may be used alone or in combination of two or more.
陰極室に添加する可溶性白金族化合物は固体状
態であつてもよいし、水溶液状態であつてもよ
い。また陰極室への可溶性白金族化合物の添加方
法は連続法でもよいし、間歇法でもよい。 The soluble platinum group compound added to the cathode chamber may be in a solid state or in an aqueous solution state. Further, the method of adding the soluble platinum group compound to the cathode chamber may be a continuous method or an intermittent method.
陰極室へ添加する可溶性白金族化合物の量は、
陰極投影面積１平方メートル当たり毎時10-8モル
以上10-5モル以下がよい。10-8モルより少ないと
白金族添加による水素過電圧回復は不十分であ
り、10-5モルより多いと水素過電圧の回復による
電力メリツトより添加する白金族化合物の価格の
法が高くなり、経済的でなくなる。陰極室への白
金族化合物の添加は電解中に行うのが一番効果的
であり好ましい。 The amount of soluble platinum group compound added to the cathode chamber is
It is preferable that the amount is 10 -8 mol or more and 10 -5 mol or less per hour per square meter of cathode projected area. If it is less than 10 -8 mol, hydrogen overvoltage recovery due to platinum group addition is insufficient, and if it is more than 10 -5 mol, the price of the platinum group compound to be added will be higher than the power benefit from recovery of hydrogen overvoltage, making it economical. It will no longer be. It is most effective and preferable to add the platinum group compound to the cathode chamber during electrolysis.
「作用・効果」
本発明によれば、従来法の如くセルを長期間停
止させ、煩雑な低水素過電圧処理を施すことな
く、通常の運転を続け乍ら、劣化した低水素過電
圧陰極の活性を回復させることが可能となり、そ
の産業上の有用性は甚大である。"Operation/Effect" According to the present invention, the activity of the deteriorated low hydrogen overvoltage cathode can be suppressed while continuing normal operation without stopping the cell for a long period of time and performing complicated low hydrogen overvoltage treatment as in conventional methods. It is now possible to recover, and its industrial usefulness is enormous.
「実施例」
以下、実施例に基づき本発明を説明するが、こ
れらにより本発明は限定されるものではない。"Examples" The present invention will be described below based on Examples, but the present invention is not limited by these.
実施例 １
４cm×10cmの投影寸法を有する鉄製エキスパン
ドメタルの表面を無電解ニツケルメツキし、更に
その上にニツケル50wt％、アルミニウム50wt％
の組成を有する200メツシユアンダーの粉をニツ
ケルメツキ浴中で分散メツキし、低水素過電圧陰
極を製作した。該陰極を20％NaOH、50℃18時
間処理し、デユポン社「ナフイオン（登録商標）」
膜を用いて温度90℃、NaOH32％、NaCl200
ｇ／、電流密度23.5A／ｄm2の条件で電解し
た。この時の陰極の水素過電圧は0.10Vであつ
た。Example 1 Electroless nickel plating was applied to the surface of expanded iron metal with projected dimensions of 4 cm x 10 cm, and 50 wt% nickel and 50 wt% aluminum were further applied on top of it.
A low hydrogen overvoltage cathode was fabricated by dispersing and plating 200 mesh powder having the composition in a nickel plating bath. The cathode was treated with 20% NaOH at 50°C for 18 hours and treated with Dupont's "Nafion (registered trademark)".
Temperature 90℃, NaOH32%, NaCl200 using membrane
Electrolysis was carried out under conditions of a current density of 23.5 A/dm 2 and a current density of 23.5 A/dm 2 . At this time, the hydrogen overvoltage at the cathode was 0.10V.
このセルを解体し、陰極を軽く水洗後、室温で
相対湿度50％の空気中に１週間放置し、再び前記
と同一条件で電解した。この時の陰極の水素過電
圧は0.15Vであつた。水素過電圧の上昇したセル
を停止することなく、陰極室に塩化白金酸６水塩
水溶液を５×10-7モル／m2陰極・Hrの量を連続
的に添加した。セルの電圧は徐々に下がりはじ
め、約３日で一定電圧となり、その値が連続し
た。その時の陰極の水素過電圧は0.10Vであり、
劣化する前の値に回復した。 This cell was disassembled, the cathode was lightly washed with water, and then left in air at room temperature and relative humidity of 50% for one week, and electrolysis was performed again under the same conditions as above. At this time, the hydrogen overvoltage at the cathode was 0.15V. Without stopping the cell in which the hydrogen overvoltage had increased, an aqueous solution of chloroplatinic acid hexahydrate was continuously added to the cathode chamber in an amount of 5×10 −7 mol/m 2 cathode·Hr. The voltage of the cell gradually began to decrease, and after about 3 days it reached a constant voltage, which remained constant. At that time, the hydrogen overvoltage of the cathode was 0.10V,
It has recovered to the value before deterioration.
実施例 ２
実施例１と同一の条件で製作、電解、劣化させ
た低水素過電圧陰極を有するセルに、塩化白金酸
６水塩水溶液を３時間毎に間歇的に1.5×10-6モ
ル／m2陰極の量を添加した。塩化白金酸水溶液を
加えるたびに電圧は徐々に低下し、約３日で一定
電圧となり、その値が連続した。陰極の水素過電
圧変化は次の通りであつた。Example 2 A chloroplatinic acid hexahydrate aqueous solution was intermittently added at 1.5×10 -6 mol/m every 3 hours to a cell having a low hydrogen overvoltage cathode manufactured, electrolyzed, and deteriorated under the same conditions as in Example 1. Added an amount of 2 cathodes. Each time an aqueous chloroplatinic acid solution was added, the voltage gradually decreased, reaching a constant voltage in about 3 days and remaining at that value continuously. The hydrogen overvoltage change at the cathode was as follows.
水素過電圧 劣化処理前 0.11V 劣化処理後 0.16V 白金添加後 0.11V hydrogen overvoltage Before deterioration treatment 0.11V 0.16V after deterioration treatment 0.11V after platinum addition
Claims (1)
ルカリ金属水溶液の電気分解に使用する低水素過
電圧陰極が劣化した場合において、該低水素過電
圧陰極をセルから取り外すことなく、陰極室内に
可溶性白金族化合物を添加することを特徴とする
劣化した低水素過電圧陰極の活性回復方法。1. When a low hydrogen overvoltage cathode used for electrolysis of an alkali metal halide aqueous solution or an alkali metal hydroxide aqueous solution has deteriorated, a soluble platinum group compound is added into the cathode chamber without removing the low hydrogen overvoltage cathode from the cell. A method for restoring the activity of a degraded low hydrogen overvoltage cathode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16835287A JPS6411988A (en) | 1987-07-06 | 1987-07-06 | Method for recovering activity of deteriorated cathode having low hydrogen overvoltage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16835287A JPS6411988A (en) | 1987-07-06 | 1987-07-06 | Method for recovering activity of deteriorated cathode having low hydrogen overvoltage |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6411988A JPS6411988A (en) | 1989-01-17 |
| JPH0527712B2 true JPH0527712B2 (en) | 1993-04-22 |
Family
ID=15866476
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16835287A Granted JPS6411988A (en) | 1987-07-06 | 1987-07-06 | Method for recovering activity of deteriorated cathode having low hydrogen overvoltage |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6411988A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006183113A (en) * | 2004-12-28 | 2006-07-13 | Kaneka Corp | Method for recovering performance in salt water electrolytic cell, method for manufacturing produced caustic soda solution using cathode treated by the method and method for manufacturing chlorine |
| DE102007003554A1 (en) | 2007-01-24 | 2008-07-31 | Bayer Materialscience Ag | Method for improving the performance of nickel electrodes used in sodium chloride electrolysis comprises adding a platinum compound soluble in water or in alkali during the electrolysis |
| JP6397396B2 (en) | 2015-12-28 | 2018-09-26 | デノラ・ペルメレック株式会社 | Alkaline water electrolysis method |
| EP3597791B1 (en) * | 2018-07-20 | 2021-11-17 | Covestro Deutschland AG | Method for improving the performance of nickel electrodes |
-
1987
- 1987-07-06 JP JP16835287A patent/JPS6411988A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6411988A (en) | 1989-01-17 |
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