JPS5950195A - Regenerating method of cathode - Google Patents

Abstract

PURPOSE:To regenerate easily a cathode having deteriorated performance, by removing mechanically the surface layer part then pickling the cathode and subjecting the pickled cathode alternately to each one time of electroplating using a plating bath consisting essentially of Ni or Co dispersed with fine carbonaceous particles and a sulfur containing Ni plating bath. CONSTITUTION:The surface layer part of a cathode having deteriorated performance is removed by a mechanical means in a stage (a), and the cathode removed of the surface layer is pickled in a stage (b). The pickled cathode is then subjected alternately to at least each one time of electroplating using a plating bath consisting of Ni or Co dispersed therein with fine particles consisting of carbonaceous materials in a 0.01-200g/l range as an essential metallic component in a stage (c) and electroplating using a plating bath prepd. by adding 0.1- 50g/l thiourea, thiocyanate, thiosulfate, etc. to an Ni plating bath in a stage (d) in order of the stages (c), (d) or the stages (d), (c).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for regenerating a cathode, and particularly to a method for advantageously regenerating an active cathode for hydrogen generation whose activity has decreased.

Previously, there was a technology to generate hydrogen gas at the cathode.
4. j (Porous like asbestos (4 with 'hT;
And use 1' (including 4-v) to change your father's secret eyes like a giant.
'fgachi1') J 1. -(ttKiri, torpedo, and solution also fall under this category.

One major problem in hydrogen generation using Hf, )q'() is frost and pressure drop (S1.c
That is, hydrogen is caused by ;y′a electric fE>′F
Various active cathodes have been proposed for the separation of IT, which results in a loss of power efficiency and a loss of power efficiency.

These active cathodes are made of metals with a high degree of electrocatalytic activity, such as platinum, other precious metals, and alloys thereof, and their construction is limited due to economical considerations. Generally, a layer of activated gold with reduced hydrogen overvoltage is placed in front of the 11111 aluminum phosphor group such as iron, carbon dioxide, nickel and alloys containing these, and valve metals. , thermal spraying, pyrolysis, molten U,・
1111'/Ku\'s γ)i': i'l'f, 11\
.

Coloring is done by atmospheric plating, chemical plating, vapor deposition, etc.

The activated 1 (teζ1. East is 1[i1
When placed in the bamboo monk, it effectively contributes to hydrogen generation through electrolysis, but after long-term use, performance deteriorates and the tendency for hydrogen overvoltage to rise gradually becomes noticeable.

The causes of such performance deterioration include erosion and corrosion.
John, or impurities in the solution, e.g. 11g, li”e
, pb, etc. In particular, Fe has 1. It is thought that the leakage comes from the electrode chamber, the pipes attached to the electrolytic cell, the cathode base, etc., but in any case, a cathode that has deteriorated due to these sources will show a high sliding voltage during electrolysis.

The present inventors have investigated the possibility of regenerating cathodes whose performance has deteriorated as described above using simple means and reusing them as active cathodes.
, l L, have completed the present invention as outlined below.

That is, in regenerating a deteriorated active cathode for hydrogen generation, the present invention includes the steps of removing at least the surface layer portion (1i) by mechanical means, and acid-washing the cathode from which the surface layer portion has been removed ( (b)) and then Metskin whose main gold maple component is nickel and/or cobalt in which fine particles of carbon 7-1 are dispersed? 1 to the surface, <1
．． Plating #? qo1:41t(c)doinclude(r'L,
J'', using a nickel plating bath! TI'7. on top.
111i't1?・ of ``≠ (c) (tl or process) (c) without applying Qi Meggi to each process at least once. 1;He (Hei Shinho of Italy, "Puo Koko No. 1" will be explained in detail.

1 (f (bar is Jlt) to which the method of the present invention can be preferably applied
Rigid alkalinity with iron, fl・A, nickel and alloys containing these, pulp gold #fi/, c as already described as l, particularly preferably nickel 15 city 1
It is a former alkaline 444" containing 8% or more, and can be applied to various porous shapes, such as expanded sotonocles, wire gauze, and panbung plates57).ノ (Rigami has 1 (as shown) low hydrogen 7 hin, active metal with river + (fee is ff 1)
, thermal molecule ll'l', melt 190% 1 her,) i'
l;'Hii'j, i! f, "Q, 7' 7ki, chemical plating, vapor deposition, etc."
Activated 'n,'5 frame&j-tl:,f'
+q 1', IIIK IH is used and used for a long period of time, causing gradual deterioration.

In the method of the present invention, such deteriorated cathodes are removed from the electrolytic cell series, and at least surface R4 of the coating with reduced activity is removed (
The above step (a) of removing by mechanical means is performed. As a method of mechanical removal, methods such as 'sand blasting' and 'puffing' are used. The purpose of removing the scratches is to remove deposits on the surface of the deteriorated cathode, to improve the adhesion of electroplating in a later step, and to keep the porosity of the cathode shape constant. Therefore, it is not particularly necessary to remove the entire thickness of the deteriorated coating (although at least the surface layer may be removed).

Next, the l+, ;'r electrodes are sent to a pickling process, and the acids used include hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. concentration,
The time will be selected appropriately.

- For example, when using hydrochloric acid and the base material is SUS 310 S, the preferred pickling conditions for 11f are a temperature of 20 to 90°C.
, Dark Ba I: 5-35%, time 1 minute-180 minutes, J
For FI, preferably a temperature of 50 to 70°C, a concentration of 8 to 20%,
The time is 5 to 60 minutes.

The main purpose of this pickling is to improve adhesion in the subsequent Metsu/V process. , l+9? □Iv, i1-7
Next, the cathode is coated with a plating bath containing nickel and/or cobalt containing fine particles of carbonaceous material as the main gold component. 11. The process of applying air plating (c) and the process of electroplating the surface using a sulfur-containing nickel plating bath are performed, but this process (c) and step) will eventually be σ) Stingray 11! may be performed first, and both steps are repeated at least once.
·return. Also, the final Meggiye back may end in either step (c) or ni), but preferably ends in step).
That is, it is preferable that the final surface layer is a plating layer using a nickel plating bath containing (lflt: M). In step (c), step 71f, air plating, contains fine particles of carbonaceous matter in the plating bath in an amount of about 001 to 2CJO9/A. 2, dispersed in a range
This is VC plating using a Metsu-V bath containing Kel or/and cobalt as the main gold dust components, and R is added to the above components.
Gold 1 of N...Taku ions, such as Co, AC, (Sir,
Sn, l-L+, Zn5AH.

1't, T v-, li, Quality: ~ Determined as appropriate depending on the particle's degree and the force of gravity.

On the other hand, carbon chi 1. Fine particles consisting of charcoal, coal,
- 141 charcoal, graphite, activated carbon, carbon black, coke, etc. can be mentioned, and the particle size thereof is preferably 100μ or less, especially those with an average particle size of 10μ or less.

The plating conditions were current density (11-15 A Alrn2
It is desirable to carry out in the range of p112-6.

The above-mentioned dispersion of the fine particles is preferably carried out by blowing gas into the liquid, pump circulation, tri-stirring (mechanical stirring, etc.).

Through the process (c), the cathode surface has a low hydrogen oxide layer with a large porous surface area. ! ?
, a layer of pressure is formed.

Next, in the sulfur-containing nickel plating process, thiourea, thiocyanate, and diof4j are added to the nickel plating bath.
n'2, thioglycolate, etc. are added, and the concentration thereof is preferably in the range of about 0.1 to 509/13.

The plating current is 0.1 to 15A/12, p
112-6 to be carried out at h1' (2.
T effect 1. (It is also useful for reinforcing the plating with carbon'6 particles that was done in the previous step (c). (It is important to delay deterioration due to unfavorable materials and allow long-term use.

In the method of the present invention, the regeneration of the cathode including each of the steps (a) to (a) above is carried out in step 1 ((with the pole installed in the cathode chamber of a small one-sided tank)) is desirable.

711, including the shade 45 that requires regeneration.
? ! r, from the tank disassembly series, take measures to shield all parts of the Ln pole other than those that require regeneration from the residue, and pickling A.
l,? I! , Key points s3 inside the cell are plated.
1+, perform the work after making i old possible.

This ringing, the removal of the yin 4 and the 11 of the yin (A)'(a) was carried out using a wire brush, etc., and the r and ri8 δ1 of the T culm (b) were 1" ``It is done by pouring an aqueous solution of 1'9I'', Yinmotoshin, To λ (1 bottle; (etc.).
It is strange that it is old, including 4% or more.

For example, if the metal is made of iron, there is a risk that the electrode chamber will be exposed to II', + film and the life of the storage chamber will be shortened.

After this pickling, a reverse current is applied in the acid aqueous solution.
It is also effective to elute impurities in the IF, l, and deterioration r; and γ terms, and this 18th case is particularly low. (f, flow density (I A, / (,11112 or less)) It is desirable to carry out J7 hours. After this operation by flow, pickling ΔIY may be performed again.

The lightning and air plating in the next steps (c) and 2) is performed by filling the cell with a plating solution and using a mating electrode set separately.
lH'r, j'>+ It is preferable to carry out 4jll stirring 1 to 1 times using an aeration tube for stirring/1ζ.

(-1 and 2) may be performed first in any order, but it is desirable that the process (-1 and 2) be the final step, as stated in the bif.

According to the above-mentioned bending method, the present invention includes:
, comparative giant r + i'i, 'l calculation, c-1'' stage, the most desirable hydrogen is
1. c il" J L 1.'l l古↑'l l'
1; 44(wo(',) 71 ko, -kar out 21/
, 7-, Red due to long-term use of the cathode (along with the jt effect, ili, force efficiency improvement' is twice as large as 1''j [f!'
, 5a) The bolted out IJ1 (is).

The present invention will be explained below with reference to Examples-1.

Method JA Vsu1 Nickel-filled Expantomeckle (Ro5SW x 8L
W X 1', L) Turning in the force direction, 1゛ is the thickness, W represents the increments ri.
& Group 14 and [2, its surface 1 (N i -Ae (5
(+: 50 Tlj iii ratio) alloy on both sides about 1
00/l 7", 2 degrees thermal spray L, next iteration Ar residue:
00''(,', 6hv-), then filtered (1% NaUlI), immersed in 1'1Ilv-, immersed in 8U°C, and washed with water.
The pole is welded to a nickel rod (gold rod*, 11゛l).
I was able to ask.

Ka\rul:f Intestine Izun Bunshiro 1fi with i chamber! 75
．． 1□I'f tank (double (; temporary type) to the anode chamber ~J = water 1 (supply, 1st chamber 11 (water 1, r included)) 3 In this case, ll3 i
j7 '1Jji 11741 (L side 132%,)l
', itK, density 30 A/d n12, wet+t
The tank was operated under conditions of Bo℃, and the tank market pressure was maintained at 2.98 V at the beginning of operation, but after one year, the pressure had dropped to 615 ■. At this point, the cathode potential was measured /), jf+'M
The city's 11th floor was found to be rising by approximately 0.1cm, so operations were stopped. Den lIl'I! Dismantle the tank and remove the cathode
F: Take out the persimmon ZT Godo IIV and apply wire brush over the entire surface of the cathode. As a result, the cracked material on the surface was peeled off by ftJ1 ~ +;++t.

Then 6. It was immersed in N-1ick at 50°C for 30 minutes and washed with water. After washing with water, the following bath composition and plating Φ conditions are included (
1.ff Yellow nickel plating was performed, but before this plating, the area other than the cathode surface was bordered in A' color with vinyl tape.
child.

[Plating bath WII formation]

IIW acid = yKel 84g/e dichloride,Kel 0 ammonium chloride 4.5# (, porous potash
6 “Poric acid
3 (] j7 / -e thiourea
2 (l 〃 [Plating item] Opposite pole 1.5 d 1TI22,
Kel board Ti￥, 1iir,
5 A plating time: 3 [) minutes Plating temperature: 40°C pH 3-4 After plating the soil plate, wash thoroughly with water and coat with carbon 7' (
Plating was carried out in a T-joint plating bath of 1+ by placing it in a 1x plating bath containing f cold particles.

Dispersion of charcoal (11) was carried out by pumping the liquid (1n12/IIY-).

[Yukagumi Kiyoku Aisei]

i1i+-: i', j9 Nickel #8
4 g / (3 dichloride, kerosene) Ammonium 4.5 Potassium chloride 6 Boric acid 30 Activated carbon 20 (J Kagaku KV-3) IL
f l″;? 51″I
0.6 [Plating conditions] Opponent 4: frL, 1.5 (I m2=-) Kel plate 1
, f, jn,
5A Plating time: 40 minutes Plating temperature: 40"c pal 3.5~4.5 After performing this plating, wash with water and apply the above-mentioned (+if PC nickel plating - carbon'/'j fine particle content 11 (plating to 61i,
ll!・1′! return,? 1. A self-sustaining active cathode was prepared using sulfur-containing Niakermeggi (111/11 L).

This second 'fl' was assembled into a trading tank and operated under the same conditions as in the previous case. Initially 2.99V 3.0 after 6 months
By adding 1V and adding it to X'4, you can turn the warp into a warp.

Example effective surface) Li't 100 dm'? , JMff1 type cation exchange membrane tun) 1 + 1 "1" is used to prepare an aqueous solution of potassium chloride, about 7.

Kono City, f'i'(t2'l',) l''"4KT
< 8 <C4'4','A,' S U S 3108
wo use '1・;su, 1 included, 1. (1yoS
IJ 8, '+ 1 [1B 'j Pap's Expanded Metal (6,5S~■×ε)1haVxll'xl~■)
Charcoal on the surface of
゛:6、S】Tame,・Kiba nayo~・lkoiIjki metsumetsugiishi Rj? I Nickel Metsu hemorrhoid bath is plated with 1 and 1 filter frost plating.

Potassium chloride water soluble 71 by Karu City, Bu', 'f4:'J
゛''Ij m, jl'f is the current density 25 A /
(11112, humidity 90'?;, K(moon(γ1゛λ11
゛In Section 4-28 lIi↓vJ5. D 6 It was operated by V's Tankungetsu, but while it was in operation, it was 1.1 from the Il'j ring line of KOIT.
0.1 to 2 pp+n, and after 6 months, the tank was removed from the ゛ series. Then, the opposite sides of the anode and cathode chambers were sealed with vinyl sheets.

In addition, using the plate of the anode chamber (the copying surface is 4r'I and Jy3), overturn the entire surface and fix the iron plate with a clamp, P, I5.
: Fill with pure water, acid and plating bath car for 18 people/r
Seal the catholyte thoroughly so that it is l, -9.
A pine pipe with approximately 150 holes made of vinyl chloride wood 1III Jt゛4 and 05 yθ) was inserted into the pipe (1-inch pipe).

To regenerate this active 1'1 degraded cathode, first sandblast the cathode surface. This was done using #80 sand (manufactured by Nippon Kari) for about 10 minutes, leaving a coating layer on the entire surface.

This was immersed in 6N-11C at 50°C for 60 minutes, and then washed with water.

Next, electroplating was performed using the carbonaceous fine particle dispersed plating bath of Example 1 under the following plating conditions. Note that 1', V,
Stirring was performed with air using an aeration pipe, and air was also separately introduced into the shade room through the % inch pipe.

[Plating conditions]

Opposite electrode Ni plate 1.2 dm21 ■U:
? lr, 500A plating time
40 minutes plating temperature 40°C p) 1 3.5-4.5 Next, using the same sulfur-containing nickel plating bath as in Example 1, the following method 5. Sulfur-containing nickel was conducted under the following conditions.

[Meggi 1st person] Opponent Ni 11 anti 1.2 city 112 boxes,
Current: 5 (1 (IA Metsu/V time)
5 (1 minute plating temperature 40℃ Pil 3 ~ 4) I returned the shuttle 6 times to the 2 stone type 1 %j, the kimetsumettsugi ff, but after I died, the yellow nickel meggi 1h
v = went.

After plating, remove the vinyl chloride 11'11 fat sheet for the super 1 edge with JIQ and 'jK Fl? A tank was installed and the system was operated with the same amount of juice.

It showed 3.04 V at the beginning of operation, and after the 6th monthly light 3+94, it was still 3.04 V.
, 06 V, the 6th month's red color shows 5.08 V.
], I made an Iv transfer to Htp.

11 穎′ [11 fields, 11 famous bamboos＼

Claims (1)

[Claims] 1. When regenerating a deteriorated active cathode for hydrogen generation, a step of removing at least the surface layer by mechanical means (a)
, the above cathode from which the surface layer has been removed is subjected to a step (b) of RI evening washing, and then a plating bath containing nickel and/or cobalt as the main component of gold I-1 in which carbonaceous (r.! T (in the process of applying L-air plating (c) and the process of electroplating the surface using a sulfur-containing nickel plating bath) using ] A cathode regeneration method characterized by performing the steps (c) and (c) on two culms alternately at least once each time.