Sciencemadness Discussion Board

More on PbO2 electrodes

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chemoleo - 10-8-2005 at 17:01

Would you like to summarise this here so that it's on record forever, if it is such an easy and effective method?

gilbert pinkston - 11-8-2005 at 02:27

such an easy and effective method?

that possibly implies its a piece of cake and its not but it will get you O4 when you dont have any and all you care to make and it is cheap!!!! some people from what ive read have spent a fortune on this subject i use a $3 power supply or cheap battery charger and homemade Pb(NO3)2 .......i could go on but would just be repeating what ive already posted (with some pix) and should be avaliable

12AX7 - 11-8-2005 at 07:14

Quote:
Originally posted by gilbert pinkstonand homemade Pb(NO3)2 .......


So it's the same old "plate PbO2 out of nitrate solution" trick?

Tim

gilbert pinkston - 11-8-2005 at 12:48

So it's the same old "plate PbO2 out of nitrate solution" trick?

Tim


yep it works for me but it ain't purty

neutrino - 11-8-2005 at 12:58

Could you clarify your last couple of posts? They make no sense.

Plating PbO2 from Pb Acetate

jpsmith123 - 12-8-2005 at 09:18

Well, I'm getting ready to try to plate PbO2 onto a tantalum rod and also onto platinum wire.

I would like to use a lead acetate plating bath, as mentioned here:

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...

Unfortunately this web page doesn't go into too much detail regarding the process and composition of the plating bath. All it says is: "The lead acetate should be at a concentration of 0.5 mol/dm^3, + acetic acid and the current density fairly low".

I wonder about things like optimum temperature, current density, pH, whether stirring is required, cathode materials, additives, etc.

Does anyone have access to the references mentioned on the page: "Journal of Applied Chemistry 16 (1966) p180. See also Metallurgical Transactions, vol 16B, (1985) PP 489 - 496".

I would really like to see the Journal of Applied Chemistry article on the subject before trying it.

BTW, there's a guy selling 12 inches of 0.5 mm diameter pure platinum wire on ebay right now for $33.00. With platinum now being at $921.00 per ounce (and moving steadily upward), this seems like a fairly good deal.

http://cgi.ebay.com/PLATINUM-WIRE-12-inches-99-9-PURE_W0QQit...

vulture - 12-8-2005 at 10:08

Quickie question? Why do you want to coat platinum or tantalum with PbO2? They are both good enough as is for chlorate electrolysis, if that's the intended purpose.

12AX7 - 12-8-2005 at 11:11

Doesn't tantalum kinda anodize in solution?

You didn't mention perchlorate either, cheap graphite can be used all day for chlorate. Most PbO2 goes for perc.

Tim

gilbert pinkston - 12-8-2005 at 14:00

NaClO4 crystals made with graphite then PbO2 from NaCl
http://eseephoto.com/albums/47156/019294_189044.jpg

12AX7 - 12-8-2005 at 18:57

Those are quite large indeed. Wouldn't it be cool if they were colored? :D

jpsmith123 - 13-8-2005 at 07:51

I think platinum is only suitable as an anode for chlorate production in cases where low chloride ion concentration cannot occur, right? This would apparently make platinum not a good choice for a batch process (which is what most of us would probably have, I think).

Regarding tantalum, other than as a substrate for platinum or PbO2, I haven't heard of it being used directly as an anode for chlorate production.

Anyway, I'd like to go directly from Cl to ClO4, which apparently rules out everything but PbO2.

I want to try to build up a robust layer of PbO2, and then mechanically remove the substrate.

Does anyone have access to the article: Journal of Applied Chemistry 16 (1966) p 180? I'd really appreciate any details regarding the Pb Acetate plating bath that might be in this paper.
Quote:
Originally posted by vulture
Quickie question? Why do you want to coat platinum or tantalum with PbO2? They are both good enough as is for chlorate electrolysis, if that's the intended purpose.

PbO2 ceramic substrate anode progress

Cyrus - 14-9-2005 at 15:53

I fired all of the ceramic substrates I described earlier. Some cracked, but that's what you get for firing ceramics in a 6" wide "kiln". But I did make enough that I have plenty. :)

Next, I tried to get lead nitrate to dip the substrates in, after which I would have let them dry and then dipped them in bleach to fill the ceramic with PbO2.

I figured that nitric acid ought to attack lead, since lead nitrate is soluble in water. I stuck about 105 g (IIRC) of lead in a 600 ml beaker, added water until it read at 150 ml, and then slowly added 70 ml of 61-70% nitric acid. It bubbled vigorously at first, probably because of the corroded lead surface, but after a while the reaction seemed so significantly slow down, with little bubbling visible. (20 ml of acid had been added) I added the rest of the nitric acid, and bubbles still formed really slowly. It doesn't make sense that lead would be passivated if lead nitrate is soluble. The bubbles formed were clear and odorless as far as I could tell, but I didn't sniff much.

Cyrus

Twospoons - 14-9-2005 at 18:43

I made my lead nitrate with 60% acid - no dilution at all. The lead dissolved nicely - though there was some NO2 released. You can speed the process by first pouring the molten lead into a bucket of water, slowly, from a height of about 1 metre. The lead drops deform into thin flat 'splats' and freeze in the water, giving you a huge reaction surface.

Fleaker - 15-9-2005 at 13:02

Additionally, lead can easily be pounded/rolled out flat for a higher surface area. Much safer than casting shot.

Believe it or not, casting shot isn't exactly as straightforward as it would seem and I wouldn't recommend doing it without wearing long sleeves/pants, face shield, and a heavy apron. Lead isn't too bad since it's dense and at a reasonably low temperature. Aluminum, however, is not a good metal to pour into water as getting molten aluminum on your skin is worse than molten iron. (Aluminum will stick onto your flesh while iron will pop off because of the water content.)

Why Not Conductive Substrates For PbO2?

jpsmith123 - 12-11-2005 at 15:12

I've read of ceramic substrates being used to avoid the problem of conductor erosion due to pin holes and cracks in the PbO2 coating. But would this still be a problem if the electrical connection was made only to the PbO2 layer?

IOW, what difference would it make if the substrate were a conductor (say almost any convenient metal), or a nonconductor, so long as the electrical connection is made to the PbO2 layer itself and not the conductor?

Cyrus - 12-11-2005 at 23:28

What are you thinking of using? Metals tend to erode in a perchlorate bath, and getting a perfect lead dioxide coating is pretty hard.

Why not ceramic AND conducting? ;)

The lead nitrate is still just sitting in a beaker, and there are lots of fine white crystals on the bottom. I'm betting that after a month or so, the reaction is complete. The ceramic substrates have been fired. I guess I can make PbO2 anodes now... :) I'll just need to find time.

Cyrus

jpsmith123 - 13-11-2005 at 05:58

I was thinking you could use almost any metal that would hold up during the PbO2 plating process; even graphite.

When I eventually get around to it, I plan on using a lead acetate/acetic acid plating bath.

My question is: Would pin holes really matter very much if, during operation of the perchlorate cell the electrical connection is made to the PbO2 itself and not to the conducting substrate?

Pinholes

MadHatter - 13-11-2005 at 09:32

Electricity flows along the surface so any pinholes in contact with the PbO2 would
become part of that surface and be attacked in the process. It's essential that there
be no pinholes or use a non-conducting substrate. I found this to be true even using
graphite. With pinholes it's like telling the chlorine/oxygen - ATTACK HERE !

[Edited on 13-11-2005 by MadHatter]

jpsmith123 - 13-11-2005 at 12:44

Madhatter, when you were using your graphite substrate lead dioxide anodes (GSLD), where did you make your electrical connection, to the graphite or to the PbO2 layer itself?

As I understand it, the problem with pinholes in a conventional GSLD anode is that the substrate will eventually disintegrate, thereby shutting off power to the PbO2 layer. But if you're not depending on the substrate to be an electrical conductor, then I don't see how pinholes would be a problem. Maybe I'm missing something obvious here and if so I apologize.

BromicAcid - 22-11-2005 at 21:15

This usually isn't my style but I haven't gone through all of the posts on PbO<sub>2</sub> and therefore this may already be posted somewhere or be on the FTP. Never the less, here is a link to a review that I found on the lead dioxide electrode, lots and lots of information, it's a pdf, 2.7 megs or so, 25 pages, however only a few are specificaly on making the electrodes, many are on their properties and uses:

http://www.destructve.com/sciencemadness/cr60280a003%5B1%5D....

Lead Dioxide

MadHatter - 22-11-2005 at 23:51

Bromic, Thanks for the link ! I downloaded and pushed a copy to my FTP under
the "CHEMISTRY - INORGANIC" folder.

jpsmith123 - 23-11-2005 at 18:43

Hmmm...unless I've misunderstood, that article apparently claims that you can't plate PbO2-beta from a lead acetate solution; only the less-than-desireable alpha form.

Does anyone have access to the following references: "Journal of Applied Chemistry 16 (1966) p180. See also Metallurgical Transactions, vol 16B, (1985) PP 489 - 496". It would be much appreciated.

installation lead dioxide anodes!

SAM4CH - 10-3-2006 at 04:02

I made few anodes of lead dioxide on Gouging rods "20cm*0.8cm" the thickness of plating layer was "0.9-1.5mm" but I faced many mechanical and electrical problems:

1. high temperature in DC electric connection with the head of anodes.
2. longitudinal cracking in some anodes after the first process and other in the 2nd and 3th...
3. strange brown layer on anodes.

Notes:
Current density was 15-18mA/cm2, and the temperature of solution was 45-50ºC, The cathode was 316 stainless steel, the electrolysis cell was closed and there was an outlet for hose.

I added water "not slaty water" for increasing the level of solution which was evaporating during electrolysis peocess.

I used NaCl "techinical grade" and tape water.

I was test the time for electrolysis by using Methylene blue, and at the end of process I used AgNO3 as indicator for Cl- ions but there was not any precipitate!!?



[Edited on 10-3-2006 by SAM4CH]

jpsmith123 - 10-3-2006 at 22:33

So, how much perchlorate did you get?

Also, I'm wondering, did you get a lot of chlorine gas from your cell during the chloride to chlorate phase?

I turned my pool chlorinator based cell on for the first time yesterday, but it made more chlorine than I expected, and even though I did it outside, I had to turn it off until I can find a better spot for it.

SAM4CH - 11-3-2006 at 15:32

I got about 250g sodium perchlorate from 170g NaCl

I used a buffer "NaF" So, it was not much of chlorine gas but at first 10minutes I noted it was so much.

ClO4

MadHatter - 11-3-2006 at 21:54

SAM4CH, I also found that NaF increases the efficiency of the cell. Dichromates and persulphates
work well although dichromates won't help PbO2 rods. Sorry it took so long to get back to this
thread. BTW, congratulations on your yields !

Jpsmith123, I connected the power supply to the graphite - not the PbO2. The PbO2 layer is
too fragile for my clamps.

jpsmith123 - 12-3-2006 at 01:31

SAM4CH, did you boil and then cool the cell liquor to get the NaClO4 out, or did you add KCl and precipitate out KClO4 and then calculate your equivalent NaClO4 yield?

Also, you're saying, all the PbO2 anodes you made cracked?

SAM4CH - 12-3-2006 at 03:45

No, I recrystalized NaClO4 after add few milliliter of HCl to destroy any chlorate remain and then I boiedl the solution and collected the moisture crystals.
I said PbO2 anode was cracked through electrolysis for more than one electrolyte, e.g. I faced cracking at first electrolyte for one of my anodes, and after 2nd or 3th electrolyte all of my anodes was cracked.
Note: every electrolyte take about 4-5 days.

PbO2 on Steel!!

SAM4CH - 5-5-2006 at 14:48

I'd like to ask about the typical bath for deposition PbO2 on stainless Steel?

and what about making perchlorate with no corrision of lead dioxide electrode within few weeks?!!

SAM4CH - 6-5-2006 at 16:06

What about fluorine modified lead dioxide!!?

st0ne - 30-6-2006 at 05:28

Several days ago my PbO2 anode was complete. I used the method described here: http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...
My plastic substrate is covered with 1mm black PbO2 layer. Its surface is 220 cm^2 but 50 cm^2 are useless because they are conected to two graphite plates which carry the current.
Yesterday I started my chlorate cell with this anode, mild steel cathode and 5V/5A power supply. At the beginning everthing was ok. The current was 3.5A and I left the cell for several hours. When I came back the current was less than 1A. It was 0.08A. I checked everything: power supply, cables, the cathode and the anode. And it seems that the resistance of the anode now is very high. I washed it with water and recreated all connections but with no effect. I really don't know what happened with my anode. I use table salt and tape water. May be this the problem?

12AX7 - 30-6-2006 at 13:13

Don't you need a persulfate or fluoride additive to go with PbO2? (I recall chromates don't work.)

Tim

st0ne - 30-6-2006 at 13:38

Persulfates and fluorides increase the current because it gets lower and lower over time but it doesn't change so fast. From 3.5A to 0.08A in less than 10 hours. And it was so low even in a brand new NaCl solution. In my view something happend with the anode but I don't know what.

12AX7 - 30-6-2006 at 19:40

Yeah no doubt. Seems to me the connection is bad...perhaps the PbO2 layer is fractured, perhaps at the electrolyte level say?

Tim

st0ne - 1-7-2006 at 03:18

I didn't see any cracks but maybe you are right. I will put the anode in the plating solution for several hours to fill any possible cracks.
And is the temperature of the plating solution very important? I ask because I didn't maintain it very well. It was between 20 and 50 centigrade.

[Edited on 1-7-2006 by st0ne]

Rosco Bodine - 14-9-2006 at 09:30

Something which could be worth looking at is the
lead oxychloride materials . I have no idea what
if any may be the usefulness for an electrode or a
substrate , or even if it is conductive , but it would
seem likely that it would be .

I have not looked into this at all , but it could be that
these lead oxychloride compositions may be formed
similarly as are the better known zinc oxychloride cements . There may be some mixture of lead oxides
and lead chloride which could be heated together to
a melt or a fusion and reaction point , which would set up
to an oxychloride cemented composition having usefulness .

Also there is a reaction between glycerine and lead monoxide which is known to form a self-setting cement ,
and this may have some usefulness as a binder or substrate .

Some alloyed perhaps eutectic fusion mixtures of lead chloride , lead chromate , lead phosphate , and lead sulfate in mixture with lead oxides could might also have usefulness as an electrode or a substrate . What I am thinking here is along the lines of something like a ceramic which is formed entirely from lead based compounds . Possibly also a cold formed mixture of these materials could be found useful , something which would mix together as a paste and then set up from reaction , as a cement .

The following page contains a bit of information on the
oxides and oxychlorides .

http://www.1911encyclopedia.org/Lead


[Edited on 14-9-2006 by Rosco Bodine]

Rosco Bodine - 14-9-2006 at 15:58

Adhesive backed Velcro is another material which might have usefulness in some arrangement as a substrate upon which to apply a paste of PbO2 . What I am thinking here is that when secured to a rigid backing like
polycarbonate or plexiglass , perhaps using additional adhesive like a polyurethane varnish painted on the backing and dried till it has a very firm stickiness , that
it should be dimensionally stable after it hardens and cures completely . The open loop texture of the velcro should secuely hold and reenforce the paste rubbed into that textured substrate , and then additional material could be electroplated onto it . Possibly there could even be uses where the lead dioxide paste could be sandwiched in the middle between mated reenfoced velcro substrates like a PbO2 sandwich .

Is nylon attacked in a perchorate cell ?

not_important - 14-9-2006 at 19:36

Some lead oxychloride containing other oxides form glasses that seem to be conductive, no idea what the physical attributes are.

http://www.iop.org/EJ/abstract/0953-8984/6/31/018

http://www.iop.org/EJ/abstract/0953-8984/11/41/304

Rosco Bodine - 14-9-2006 at 21:11

One of the lead oxychloride molten glass compositions is used to fill fissures in flawed diamonds to improve their cosmetic appearance . So evidently it will stick to carbon of the diamond variety , so there's a chance it might stick to graphite or amorphous carbon as well , and could possibly make a good bonding and sealing layer on carbon or graphite for later plating of PbO2 . The melting point is relatively low for that oxychloride used on diamonds and I have no idea what its electrical property
is , or what is the formula ....probably a trade secret .

Rosco Bodine - 15-9-2006 at 10:57

Another idea for a substrate is those perforated epoxy and fiberglass prototyping circuit boards having the holes on 1/10 inch centers , used as a stiff backing for
a thick filter paper blotter or felt or mat or batting material , which could be used as an absorbent for
either a paste of PbO2 physically rollered into the
absorbent mat , or used to absorb Pb(NO3)2 , which
is later chemically converted to precipitate the PbO2
trapped in the absorbent material . Cut lengths of
solid braided rope or cordage lashed to the perfboard
might also make a useful absorbent .

The absorbent felt could be secured to the proto board
backing by lacing it down with fluropolymer fishing line
and a sailmakers sewing needle , using the holes around
the perimeter as anchorage and securing it with parallel
lines as if it was a 1/10 inch mesh window screen being
sewn , adding any loops where desired to firm cinch down the absorbent mat to the perf board backing .

If proto board and filter blotter doesn't hold up to the conditions in the electrolyte , then teflon sheet and fiberglass mat or heavy fiberglass cloth could be substituted .

Another idea for using solid braided cordage or rope as an absorbent substrate is to bring one end through the bore of a teflon tube and begin to wind a tight spiral
around the outside of the tube to its top . Woven fiberglass ribbon or hollow braided sleeve could be used in a similar way .

Another thought .....

Perhaps adding some diatomaceous earth and/or chopped glass whiskers , and or grog to the PbO2
paste used for massive PbO2 anodes which are pressed damp and then baked or fired to cure , would give some
added strength to the finished article .

For a commercial application , there is an idea which
I have had concerning the massive PbO2 electrode . It involves the use of a solid teflon or other
suitable plastic threaded rod as a core substrate ,
but the thread is a dovetail groove spiral routered using a high speed dental bur . The PbO2 paste would then
be securely held by the spiral dovetail groove cut into
the surface of the substrate . Alternately , an Acme
thread , having additional longitudinal parallel spline cuts which have the dovetail profile could work , or simply using lengthwise dovetail spline grooves alone might suffice to provide a mechanical anchorage for the PbO2 paste . The idea is to provide keystone shaped protrusions rising from the substrate which are wider at
their free ends , so that they act as retainers dovetailed
into the PbO2 layer , securing it firmly to the substrate .
A cylindrical anode made this way could then have
an open mesh screen further wrapped around the
outside , and the PbO2 would be so well secured
that it wouldn't be going anywhere anytime soon .

Rosco Bodine - 18-9-2006 at 20:07

I have found what may be the easiest idea yet for for a porous ceramic substrate for PbO2 anodes .

Those sintered ceramic airstones which are used for
aeration of the water in aquariums look like a good candidate .

Here's a couple of links .

http://www.marinedepot.com/md_viewItem.asp?idproduct=AP7255

http://www.wonbrothers.com/product/airstone/airstone.htm

The flat type is interesting also .



[Edited on 19-9-2006 by Rosco Bodine]

FrankRizzo - 13-1-2007 at 22:47

*BUMP*

How about using carbon fiber cloth as a substrate?

FrankRizzo - 26-1-2007 at 15:35

Rosco,

Did you ever get a chance to try impregnating air stones? With the availability/price of perchlorate quickly becoming an issue, this might be a great time to revive the topic.

I just picked up a 12" Sal Chlor anode from the Direct Pool Supplies company in Australia. With postage, it worked out to ~US$85. When it arrives in a week or so, I'm going make a few runs and I'll report back.

A better preparation of a lead dioxide anode

Per - 27-1-2007 at 06:05

I found a side which explains the preparation of a lead dioxide anode by oxidiseing lead of the surface of a graphite rod.

The autor wrote that these anods hadn´t a realy long live because of the wear.
Sorry, I kan´t find the page any more.

I have another idea to produce such a anode with maybe a longer live.
I would oxidise a lead rod with maybe a NaOH solution as anode, it should make PbO2 on the surface which should be stronger against wear because it´s bandaged with the lead in the centre and not just with graphite.

But I´m not sure if these methode would be successfull, what do you think about it?


Sorry for my english I hope you understand me, maybe 100 posts later it would be acceptable.

aam - 27-1-2007 at 17:10

Maybe, PbO2 is unstable in NaOH solution.
"Lead dioxide dissolves in alkali hydroxide solutions to form the corresponding plumbates.

PbO2 + 2 OH– + 2 H2O → Pb(OH)62–

[Pauling, Linus General Chemistry, W.H. Freeman 1947 ed.]

I don't know much. What work do you perpare it for?

Dann - 27-1-2007 at 18:36

Hello Folks,

It is good to see a discussion of this 'old chestnut', ie. Anode
making etc. I'm the guy who has spent far too long in his
garage (as someone here said)!
Back in 99 I put up the page on Chlorates and Perchlorates on 'Yahoo-GeoCities'. It is good to see people are reading the info. I put up the page after alot of discussion with other folks at the time. Most of the page is really a collection of other peoples work but I have spent some time myself making Anodes and (Per)Chlorates and diging out articals from Libraries and the net. The ultimate goal was to be able to make a simply rugged Anode from easily obtainable materials. Me thinks there is still some work to be done.
I think it is fair to say that the Lead Dioxide Anode is still
an elusive beast. It is realitively easy to make an Anode but to make one that willl last for a long time in the (Per)Chlorate cell is another matter. Then there is the matter of all thoses horrible toxic Lead compounds...
I managed to make a ceramic substrate Lead Dioxide Anode that lasted for 3 months in a cell 24/7. It was (alas) a one hit wonder, I could never repeat this. Some Anodes I made since only lasted 10 minutes:mad:
It would be nice if one could make a non toxic Anode like Magnetite or Manganese Dioxide.
There is nothing wrong with using Graphite to make Chlorate, in fack I thing it is oftern forgotton in the rush to reach the 'holy grail' (as someone here put it) of the Lead Dioxide Anode.
If using Graphite, keep solution temp. low (use large vessel), keep current density low, keep Chloride concentration high, too hell with current effeciency. It is better IMO to have a long lasting Anode and to take your time.
It would be nice to experiment with using Graphite to make Perchlorate using pure Chlorate (no Chloride) to see what wear rates on the Anode are like. I have never done this. Always assumes you simply could not get Perchlorate using Graphite.
Magnetite I have used to make Chlorate. It was a rugged Anode that was impossible to wear out even at very high current densities. The Anode was make with a blow torch and ceramic store Black Magnetic Oxide.
Some guy here suggested getting a magnet the shape of a bar, sticking the stuff to it (it will stick itself) and seeing what happened. Seems too good to be true but you never know.
I have also make a magnetite Anode of sorts using a oxy-fuel blow torch and a rod of mild steel, but never got around to trying it out. (shame on me)

I will start this crusade again.............. Hopefully I will get out of the garage at least once a month (for 10 minutes or so!).

Dann

http://www.geocities.com/CapeCanaveral/Campus/5361/basechem....

FrankRizzo - 29-1-2007 at 08:01

Hello Dann!

Your website has been an invaluable resource for many who are looking to make lead dioxide anodes. Thanks for making all of that great information and notes of your experiments available. :-)

[Edited on 29-1-2007 by FrankRizzo]

dann2 - 31-1-2007 at 19:36

Quote:
Originally posted by FrankRizzo
Hello Dann!

Your website has been an invaluable resource for many who are looking to make lead dioxide anodes. Thanks for making all of that great information and notes of your experiments available. :-)

[Edited on 29-1-2007 by FrankRizzo]



Good to see the site is of use.

I have put some more articles in the further reading section.
Someone here was looking for some of them, I cannot find the original post/name, appologies.

They are JES August 1961, July 1957 and March 1958.

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...

I am attempting to construct a kiln of some sort (small) to melt Magnetite or sinter it. There is Kanthal wire being sold on ebay. This stuff goes to 1400C. This is at or above sintering temperature.
Could try gouging rods as elements. Carbon can go way above the melting temperature fo Magnetite.

Any ideas or pointers for home constructed furnaces.

Dann2 (formally Dann)

Rosco Bodine - 31-1-2007 at 21:56

Quote:
Originally posted by FrankRizzo
Rosco,

Did you ever get a chance to try impregnating air stones?


No , but I wish I had more time for experiments because I have a backlog of ideas that need testing :D Anybody feel free to run with any of those ideas that seem like they are worthwhile .

I did get some 3/4" by 14" gouging rods for future use .

And I spent about a month pouring over two dozen pages of schematics and data sheets to come up with what looks like a valid circuit for adapting a computer power supply to a decent precision 40+A regulated laboratory supply .

Every time I think a little project will take an afternoon .....
and soon discover it's not as simple as I first figured , I get
determined not to let it get the better of me ....and then a week or two later cringe and ask myself just what in the hell have I gotten myself into :D But it seems like the damn bureaucrat regulators are always coming up with something new , and as a consequence I seem to stay busy at formulating countermeasures .
Quote:

With the availability/price of perchlorate quickly becoming an issue, this might be a great time to revive the topic.


Yeah , and not just perchlorate ...there's a lot of interesting things you can make using electrolysis .
Quote:

I just picked up a 12" Sal Chlor anode from the Direct Pool Supplies company in Australia. With postage, it worked out to ~US$85. When it arrives in a week or so, I'm going make a few runs and I'll report back.


Yeah ...let us know .

FrankRizzo - 2-2-2007 at 08:02

Quote:
Originally posted by dann2
I have put some more articles in the further reading section.
Someone here was looking for some of them, I cannot find the original post/name, appologies.

They are JES August 1961, July 1957 and March 1958.

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...


That was I looking for those articles. Thanks for posting them up on your page for everyone to access. Someone in the references thread (Solo, I believe) had access to them, and graciously uploaded them for me as well. Although the ideas in them are definitely aimed more toward industrial processes, they're nice reference material.

dann2 - 2-2-2007 at 15:18

Quote:
Originally posted by FrankRizzo
Quote:
Originally posted by dann2
I have put some more articles in the further reading section.
Someone here was looking for some of them, I cannot find the original post/name, appologies.

They are JES August 1961, July 1957 and March 1958.

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...


That was I looking for those articles. Thanks for posting them up on your page for everyone to access. Someone in the references thread (Solo, I believe) had access to them, and graciously uploaded them for me as well. Although the ideas in them are definitely aimed more toward industrial processes, they're nice reference material.




Hello,

It's a pleasure!!!!!

Would the (good) Solo, or indeed yourself have access to

JAE (or is it JES?) Perparation and Behaviours of Magnetite Anodes.
Vol. 8 No. 4 July 1978.

Would like to read it and cannot get my hands on it.

I have some more articles relating to making Manganese Dioxide, Cobolt Oxide Anodes, for Chlorate/Perchlorate making. I will put them up on the site soon.
The Manganese Anodes seem easy to make from simple chemicals (I've said that before ) but will they be a long lasting reliable Anode?????????
Would be good to avoid those's Lead Compounds.


Dann2

Per - 3-2-2007 at 05:32

When oxidation of a lead rod by NaOh solution does not work, then what is about an oxidation with H2O2 or some other oxidators?

Elektrolytical oxidation of a Pb rod shouldn´t be so hard, isn´t it?

FrankRizzo - 3-2-2007 at 09:51

Yep, Solo posted it over in the references section. I'll attach it here as well.
Quote:
Originally posted by dann2
Hello,

It's a pleasure!!!!!

Would the (good) Solo, or indeed yourself have access to

JAE (or is it JES?) Perparation and Behaviours of Magnetite Anodes.
Vol. 8 No. 4 July 1978.

Would like to read it and cannot get my hands on it.

I have some more articles relating to making Manganese Dioxide, Cobolt Oxide Anodes, for Chlorate/Perchlorate making. I will put them up on the site soon.
The Manganese Anodes seem easy to make from simple chemicals (I've said that before ) but will they be a long lasting reliable Anode?????????
Would be good to avoid those's Lead Compounds.


Dann2


Attachment: Magnetite Anodes.pdf (438kB)
This file has been downloaded 1480 times

Eclectic - 3-2-2007 at 10:55

Dann, check your U2U messages for info on 3 missing files on your site...

hashashan - 8-2-2007 at 02:17

Hi,
I had those idea to produce a little bit simpler electrodes:
1)To take any metal ant plate electrochemically PbO2 on it. After that glue with any acid resistant glue a plastic
sheet on the PbO2 side of the "electrode" and then dissolve the metal.
2)Glue magnetite or graphite powder on plastic, electroplate PbO2. glue another plastic on the PbO2 side and
scrape off the plastic/graphite.

This method spares making PbO2( which for me is a pain in the ass).

Do you guys think it can work?

dann2 - 8-2-2007 at 18:51

Quote:
Originally posted by hashashan
Hi,
I had those idea to produce a little bit simpler electrodes:
1)To take any metal ant plate electrochemically PbO2 on it. After that glue with any acid resistant glue a plastic
sheet on the PbO2 side of the "electrode" and then dissolve the metal.
2)Glue magnetite or graphite powder on plastic, electroplate PbO2. glue another plastic on the PbO2 side and
scrape off the plastic/graphite.


Hello,

I will give my 2 cents worth and go for the following answer:

No.! I don't think it would work. The Lead Dioxide will probably crack and it will not be a nice consistent sheet of material for you to stick to the plastic. It needs to be a consistant sheet or you will not be able to get a connection to it when it is to be used in the cell.
You are in fact trying to make a massive Lead Dioxide Anode and then glue a piece of plascti to it. Why bother with the plastic. I suppose it will give it strength but if the Lead Dioxide is going to crack it will crack anyways with or without the plastic.
Try getting Lead Dioxide to plate onto/into a piece of cloth or some other sort of material (Titanium sponge/fine mesh) or something of that nature. You will then have a reinforced 'massive' Anode.
I made one of theses once (using a piece of polyester cloth) and had initial success. The Anode dissolved away. It did not fail cathostrophically (suddenly). I think I did not build up thick enough of a layer of Lead Dioxide. I called it my Cloth Reinforced Lead Dioxide Anode (CRLDA) :-)
Velcro might be interesting. It's Lead Compounds all the way though, it would be good of you could avaid them.
I ran out of enthusiasm (or did I get poisoned!).

Dann2

hashashan - 9-2-2007 at 05:11

actually i didnt mean to create a massive lead dioxide anode. but rather another process to make plastic with PbO2 coated on them.. the reason is that its a pain in the ass to make PbO2 powder and rub it into a plastic. so i thought that if i could first create the coating and then attach the plastic to it so it will gain strength then it would be ok.

FrankRizzo - 9-2-2007 at 08:16

If you have a problem finding PbO2, look no further than your nearest lead-acid battery recycling pile or near dumpsters. If you empty the electrolyte and hacksaw off the top of the battery (a PITA), you'll gain access to the cells inside. The cells are made of alternating layers of pure lead sheet and lead dioxide slurry coated electrodes. Just scrape off the lead dioxide slurry, wash it in a solution of baking soda to neutralize any acid, and then dry the powder. It will probably dry into a hard cake, but it's easily crushed back into a fine powder.

Before I received my chlorinator anode, I toyed with the idea of mixing lead dioxide powder and epoxy adhesive with limited success. I was able to make a solid rod with decent mechanical strength, but the resistance was quite high from end to end (~100-200k ohm). This would mean excessive plating times until that first thin layer had been deposited.

hashashan - 9-2-2007 at 08:35

ok ill try that. i knew it but i kinda worry about cutting a battery .. i really don't want to find myself full with lead dioxide.
btw. is it possible to coat stainless steel with PbO2?

Per - 9-2-2007 at 08:56

I also cut a battery and its not as impossible as vou think of it.
You just have to suck up the sulphuric acid and then wash the inside of the battery with much water. Then it´s very easy to cut the lead and lead dioxide anodes out of the battery.
But be careful, the lead and lead dioxide at the anodes isn´t pure lead, theres a kind of glass fibre mixed with it.

Rosco Bodine - 9-2-2007 at 10:30

Electroless silver plating like is used for silvering mirrors
could be used to lay down a conductive surface on
a ceramic rod , like those alumina rods that are used for sharpening knives . Then the PbO2 could be electroplated onto the silver . Also there are unglazed
terra cotta patio tiles that are a foot square and perhaps 3/8" thick , and maybe a 1" wide strip of that material
could be scored and broken off , or cutoff using a tile saw , and the strip of terra cotta could be used as a
substrate .

dann2 - 9-2-2007 at 19:02

Quote:
Before I received my chlorinator anode, I toyed with the idea of mixing lead dioxide powder and epoxy adhesive with limited success. I was able to make a solid rod with decent mechanical strength, but the resistance was quite high from end to end (~100-200k ohm). This would mean excessive plating times until that first thin layer had been deposited.


Hello,

I am surprised that the rod conducted at all. I tried this a long time ago and it was hopeless. The rod was a good insulator. What epoxy did you use? If you could compress the paste around a conductive rod (carbon) this would eliminate some of the resistance. It would be an easy anode to make. Would it last long???? I suppose there is only one way to find out.

dann2 - 9-2-2007 at 19:13

Quote:
Originally posted by Rosco Bodine
Electroless silver plating like is used for silvering mirrors
could be used to lay down a conductive surface on
a ceramic rod , like those alumina rods that are used for sharpening knives . Then the PbO2 could be electroplated onto the silver . Also there are unglazed
terra cotta patio tiles that are a foot square and perhaps 3/8" thick , and maybe a 1" wide strip of that material
could be scored and broken off , or cutoff using a tile saw , and the strip of terra cotta could be used as a
substrate .



A problem with ceramic substrates is the (Per)Chlorate travelling up the ceramic and corroding the connection when in use. This might not be as bad with terracotta, but terra cotta is fearly smooth and Lead Dioxide may be inclined to fall off. The advantage of a very rough (say Silicon Carbide sharpening stone) was that the Lead Dioxide adhered very well to the substrate. It attached itself to the substrate very tightly as it keyed into the surface roughness. But substrates like this conducted the salt solution very well too which made connections to Anode difficult to maintain.

If one could make Magnetite anodes easily they would be a good substrate to stick/plate Lead Dioxide to. The Magnetite is virtually uneffected by the (Per)Chlorate electrolite. (You wouldent need Lead Dioxide for making Chlorate on the Magnetite.) I don't know if Lead Dioxide will plate onto Magnetite. The Lead Dioxide/epoxy would be easily........if it worked!!!!

Rosco Bodine - 9-2-2007 at 22:25

I was thinking of the ceramic simply as a structural form upon which a massive PbO2 anode might be plated , being used as a cheap substitute rigid substrate for the alternative , which is tantalum rod or barstock .

The silver will convert to silver oxide , which like PbO2
is conductive and adherent ....the advantage for it being
that it is easily laid down chemically on a nonconductor
like a ceramic , or even glass .

Possibly the ceramic could be soaked in silver nitrate ,
then dipped into hydrazine sulfate solution to mirror out
dispersed silver in its pores to make it conductive .
The surface could be roughened , notched , even have
holes drilled in spots to provide anchorage for the
PbO2 layer which will be built up by later plating .

The anode connection can be made directly to the PbO2
using a silver wire or silver strip . Silver oxide corrosion forming at the surface junction will remain conductive . The porosity of the PbO2 could perhaps be reduced in the connection area using a silicone oil or vacuum grease , or perhaps by melted paraffin or fiberglass resin , linseed oil , ect. as a barrier against wicking .

Really when a massive PbO2 anode is the intention ,
the substrate material is somewhat irrelevant so long
as it is something rigid enough to reenforce the fragile
PbO2 and is not chemically attacked by the conditions
presented by the cell in operation , and ideally it would need a thermal expansion property near to the same as the PbO2 so it wouldn't crack and crumble from thermal
stresses during temperature changes .

hashashan - 10-2-2007 at 03:41

Hey,
I am really interested to plate PbO2 on a metal.
Anyone had any luck with Iron,Steel, Aluminum?
I mean a massive anode plated on a metal grid for strength and conductivity. so even if it will crack the metal grid will drive the current on.

Rosco Bodine - 10-2-2007 at 13:22

Quote:
Originally posted by hashashan
Hey,
I am really interested to plate PbO2 on a metal.

Then your choices are few . Tantalum , platinum ,
perhaps titanium ? but no conductive connection there
since the oxide which will form is a blocking diode junction
to current flow which would be in the direction making it the anode . It is the conductivity and the corrosion problems
which limits the choices greatly as to what can be used as a substrate on which to plate the PbO2 .
Quote:

Anyone had any luck with Iron,Steel, Aluminum?

For the PbO2 anode substrate in a perchlorate cell ? No .
Quote:

I mean a massive anode plated on a metal grid for strength and conductivity. so even if it will crack the metal grid will drive the current on.

The lead dioxide layer is not entirely impermeable , so
whatever substrate is used must have some resistance to
corrosion and erosion by the extreme oxidizing effect when
the cell is in operation . For a massive anode of PbO2 , the
electrical contact is made to the PbO2 itself , which carries the current through its mass , regardless of the substrate .
But still , the substrate must be dimensionally stable and
not corroded ....so that the massive structure of PbO2 is not cracked or crumbled away from the substrate reenforcing
it from underneath . So any surface scaling or blistering
or dissolution by chemical attack of the substrate which would change its dimensions would fracture the fragile and
brittle PbO2 layer adhering .....and this must not occur ,
or else the anode coating will disintegrate and fall away
from the substrate . There are *very few* materials which
are chemically inert enough to withstand the *powerful*
oxidizing conditions present upon and inside the anode
structure in a perchlorate cell , and which might then function
as a suitable substrate material .

hashashan - 10-2-2007 at 14:37

ok so gauging rods it is then :)

Rosco Bodine - 10-2-2007 at 15:29

Yeah a good old gouging rod , perhaps soaked in molten paraffin , or linseed oil , then roughened up a bit with
coarse sandpaper and plated with a 3mm layer of PbO2
is a good possibility . One thing extra I thought about
is perhaps winding a spiral around the outside of the
rod using some braided fluoropolymer fly fishing line ,
from bottom to top , and then doing an opposite direction
spiral wrap overlaying the first spiral wrap so as to create a spiral diamond grid sort of pattern . The idea
is that the outer spiral would have a bit of a gap space
under it , around which the PbO2 could buildup many
physical anchorage points , something like the pattern
of spiraling rebar used to reenforce round support columns made of concrete in earthquake areas . The
PbO2 would be embedded with a fluoropolymer webbing
stretched tight across the surface of the graphite substrate , so that even if it cracked in many places ,
it would not fall off in pieces because it is laced to the substrate , all around .

dann2 - 10-2-2007 at 17:46

Quote:
Originally posted by hashashan
Hey,
I am really interested to plate PbO2 on a metal.
Anyone had any luck with Iron,Steel, Aluminum?
I mean a massive anode plated on a metal grid for strength and conductivity. so even if it will crack the metal grid will drive the current on.



Hello,,

See
JES Vol.105, No. 2 (Feb. 1958) page 100.
Lead Dioxide Anode for Commercial Use

at
http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...

They mention plating Lead Dioxide onto Iron or just about any metal. The problem is that the plating solution turns more and more asicid as nitric acid forms. This attacks most metals in the bath. It wont attack the 'Valve' metals, like Ti, Ta, and others. If you want to plate Iron or Nickle, (and theses have been used to make massive Anodes using a wire as the starting point for growing the Anode) you must control the pH of the plating tank. PITB.

BTW what do you guys mean when you say a 'massive' Lead Dioxide Anode?
I use the term to describe an Anode that has no substrate (it will have a substrate when in the plating tank) when it goes into use in the (Per)Chlroate cell. For example, Anodes have been grown on Iron, the Iron then stripped away and the piece of Lead Dioxide left used as a (massive) Anode.

dann2 - 10-2-2007 at 18:01

Quote:
One thing extra I thought about
is perhaps winding a spiral around the outside of the
rod using some braided fluoropolymer fly fishing line ,
from bottom to top , and then doing an opposite direction
spiral wrap overlaying the first spiral wrap so as to create a spiral diamond grid sort of pattern . The idea
is that the outer spiral would have a bit of a gap space
under it , around which the PbO2 could buildup many
physical anchorage points , something like the pattern
of spiraling rebar used to reenforce round support columns made of concrete in earthquake areas . The
PbO2 would be embedded with a fluoropolymer webbing
stretched tight across the surface of the graphite substrate , so that even if it cracked in many places ,
it would not fall off in pieces because it is laced to the substrate , all around .




There is an Anode described in the patents somewhere that describes using a graphite substrate with a cloth sleve slid over the rod. The lead Dioxide than grows onto the Carbon and through the cloth, similar to what you describe. The author claims it wont crack.

Patents are very ofter put onto paper without rigorously testing the idea. It may work, it may not.

As far as I can find out, when plating metals with Lead Dioxide, the only metals that were suffessful in the long term were the 'Valve' metals and in order to make the Anode last a long time in the (Per)Chlorate cell you had to revert to coating the Valve metals with a Platinum group metal so as to stop an oxide layer from starting to form and isolating the metal from the Lead Dioxide when the Anode was used in the ( Per)Chlorate cell.

You could always plate a Platinum wire. Look on the Lead Dioxide layer as being protection for your precious Pt wire!

I have never had success with using a gouging rod as a substrate. The Anode always failed soon after it went into service. (10 minutes some times :mad:)
A piece of carbon that does work, according to a guy who make the Anode and used it many times, is a rod of carbon out of a large low voltage carbon zinc battery. I thing it is about 6 inches long. The battery was one cell only but was about the size of a 4 litre bucket. It might be called a lantern battery (in USA). I could never come accross one of them.

Dann2

Rosco Bodine - 10-2-2007 at 19:12

Graphite or carbon is used as the substrate for the GSLD type anode . I thought that was supposed to be fine and
had even been adopted for commercial use .

Evidently titanium can be used as a permanent rigid metal substrate for PbO2
.....only if it is plated with platinum for protection .

There is a flat braided polyester lacing tape that is used
for securing the electrical windings in motors . It is available
in many thicknesses and widths . An idea I have is along the lines on the cloth reenforced substrate for a carbon anode .
A saw cut slot could be made in the bottom of the carbon
rod , and then it could be plated with a thin layer of PbO2 ,
perhaps a half millimeter or less . Then a knot is tied in the end of the lacing ribbon and the ribbon is slipped into the
sawn slot and then pulled so that the knot seats on the
opposite outside end of the slot and anchors the lower end
of the spiral winding , laid down like a barber pole stripe ,
the edge of each winding abutting the next so that the
entire PbO2 coated carbon is wrapped all the way to the
top and the end cinched down and knotted there as well
to secure the entire winding . The plating on of more PbO2
is continued until the whole spiral wrap is permeated and
then covered completely . A massive structure of PbO2 is
not needed , as the total combined thickness of PbO2 would be perhaps 1.5 to 2 mm down to the carbon and much of that volume of material would be filled with the polyester
fiber substrate . One of these lacing ribbons is made from
a 50/50 blend of polyester and fiberglass which is what I
would recommend . If the polyester doesn't hold up well
in the perchlorate cell then probably the glass will .

http://www.breydenproducts.com/StatorLacingTapesAndCords.htm

[Edited on 11-2-2007 by Rosco Bodine]

Attachment: US4236978 cloth GSLD anode.pdf (372kB)
This file has been downloaded 971 times

dann2 - 11-2-2007 at 14:55

Hello,


The problem with patents is that they seem to make everything very simply and straight forward.
You so X followed by Y, then do Z and low and behold you have a long lasting, better than anything before device. It is not that simple in practice.

You can coat Ti with Lead Dioxide but all commercial Anodes have had (as far as I can make out) a coating of Platinum between the Lead Dioxide and the Ti. Thats not to say that you cannot make a successful Ti substrate Anode. How long will it last???. The commercial people did not seem to think they were lasting long enough and turned to protecting the Ti with Pt first. I know guys that have make Ti substrate anodes but how long they lasted I have never been told.
The commercial Anodes have to work for months and months without trouble, so perhaps I am inclined to aim too high. After going to the trouble of making an Anode it is annoying to see it fail after a forthnight.

The ultimate goal for myself was to try and get a process that would lead to a long lasting Anode that was easy to make from easily available materials. This has proved to be difficult.

Regarding coating Graphite. There are many grades of graphite. EDM Graphtie has many prices and densities. It has been suggested to me that the best types are the hardest and most dense. Gouging rods are (alas) low guality qraphite. I could never get them to last long in a cell. Perhaps it was something I was doing wrong.

There are a hugh amount of parameters like for example, pH'S, Lead Ion concentrations, temperatures, additives, acid concentrations, substrate pretreatments, current densities, power wave shapes, and more that have been suggested as being the best! This is especially true in the patents. It is difficult to sort the whole thing out and get something that worKs for you that is as simple and easy to do as possible.

The cloth around the Graphite seems a good idea to me. Try it an see how it goes.

With plating baths it is good to try and have plating conditions stable. If you decide to go with a 30C temp. try an maintain that temperature. Try and maintain the pH constant. This is not simply especially if you start with a highish pH. If you start with a ph of 3.5 the pH will start to fall rapidly as you plate as Nitric Acid forms. It may be better to start with a pH of say 1 (add Nitric Acid at start) and them the pH will not fall so rapidly. It is not easy to control pH by adding Lead compounds (Lead Carbonate say) as you plate. Addition of the stuff will cause bubbles/foaming and it is difficult to know how much to add. When pH was controlled (in articles that I have read) it was done in a seperate tank with pumps etc. Far too much trouble IMHO.

Dann2

dann2 - 11-2-2007 at 15:08

Quote:
Originally posted by Rosco Bodine
Graphite or carbon is used as the substrate for the GSLD type anode . I thought that was supposed to be fine and
had even been adopted for commercial use .

Evidently titanium can be used as a permanent rigid metal substrate for PbO2
.....only if it is plated with platinum for protection .

There is a flat braided polyester lacing tape that is used
for securing the electrical windings in motors . It is available
in many thicknesses and widths . An idea I have is along the lines on the cloth reenforced substrate for a carbon anode .
A saw cut slot could be made in the bottom of the carbon
rod , and then it could be plated with a thin layer of PbO2 ,
perhaps a half millimeter or less . Then a knot is tied in the end of the lacing ribbon and the ribbon is slipped into the
sawn slot and then pulled so that the knot seats on the
opposite outside end of the slot and anchors the lower end
of the spiral winding , laid down like a barber pole stripe ,
the edge of each winding abutting the next so that the
entire PbO2 coated carbon is wrapped all the way to the
top and the end cinched down and knotted there as well
to secure the entire winding . The plating on of more PbO2
is continued until the whole spiral wrap is permeated and
then covered completely . A massive structure of PbO2 is
not needed , as the total combined thickness of PbO2 would be perhaps 1.5 to 2 mm down to the carbon and much of that volume of material would be filled with the polyester
fiber substrate . One of these lacing ribbons is made from
a 50/50 blend of polyester and fiberglass which is what I
would recommend . If the polyester doesn't hold up well
in the perchlorate cell then probably the glass will .

http://www.breydenproducts.com/StatorLacingTapesAndCords.htm

[Edited on 11-2-2007 by Rosco Bodine]


It is not a good idea to stop the plating process and then start to plate again as there will be a risk of the second coating falling off. ie. not adhering to the first coat. Cannot remember where I read this but it definitely mentioned it in a artical I read. Since you are putting plastic rope into the Anode perhaps this does not apply so much. Polyester plastic will hold up to cell conditions.


http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...

Nylon does not hold up. Will the rope/cord be too thick?
Dann2

dann2 - 11-2-2007 at 15:46

There are some Ta bits for sale here if anyone is interested.

(WWW.TUNGSTEN.COM)

http://www.tungsten.com/mtsprod.html

See the 'orphan bin'

Rosco Bodine - 11-2-2007 at 16:54

The interrupted coating failing to resume is something
I could believe would be caused by oils from the hands
contaminating the surface as it is handled . But I think
probably wearing gloves would stop that problem .
And after the lacing is done , simply dipping the
assembly in acetone and allowing it to dry should
provide a clean and degreased condition ready for
continued plating . A dip in diluted nitric acid would
probably not hurt either before resuming the plating .

As for the resumed plating falling off , that wouldn't be possible having a cloth substrate embedded in the
layer formed during the resumed plating .

Are you using the added nickel and copper nitrate in the lead nitrate plating bath when you are plating your
PbO2 onto your carbons ? IIRC you can improvise this
additive by dissolving US nickel coins in nitric acid ,
since they are actually made of a copper and nickel alloy ,
though I don't recall if the proportions are correct .
Also there was a surfactant supposed to be used and
a very specific rate for the plating .

A threaded tantalum rod would make a good substrate
if you have $75 you would like to spend .

http://cgi.ebay.com/TANTALUM-SOLID-ROUND-THREADED-ROD-5-16-2...

[Edited on 12-2-2007 by Rosco Bodine]

dann2 - 12-2-2007 at 18:05

Quote:
Originally posted by Rosco Bodine



Are you using the added nickel and copper nitrate in the lead nitrate plating bath when you are plating your
PbO2 onto your carbons ? IIRC you can improvise this
additive by dissolving US nickel coins in nitric acid ,
since they are actually made of a copper and nickel alloy ,
though I don't recall if the proportions are correct .
Also there was a surfactant supposed to be used and
a very specific rate for the plating .

A threaded tantalum rod would make a good substrate
if you have $75 you would like to spend .

http://cgi.ebay.com/TANTALUM-SOLID-ROUND-THREADED-ROD-5-16-2...

[Edited on 12-2-2007 by Rosco Bodine]


I have used Cetyltrimethlyammonium bromide (also called Hexadecyltrimethylammonium bromide), quite a jaw breaker!

Some thoughts on surfactants here:

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...

There arel lots of claims made for different surfactants in the journals.

I always use Copper Nitrate. Never used Nickle nitrate.

The idea of the ceramic (or other totally indestructable substrate) substrate was that (hopefully) any old coating of Lead Dioxide would give a workable Anode. This proved not to be the case because of problems of the substrate conducting the salts up to the connections when used in the (Per)Chlorate cell. Also it is difficult to get a good electrical connection to the Anode if the coating is very bad.

I often thought about using Ti sponge (I don't know where to purchase this stuff) as a substrate. The Anode when formed would be treates as a massive Anode. The electrical connection being made to the Lead Dioxide itself. You might end up with problems similar to ceramic substrate though.

Dan

Rosco Bodine - 12-2-2007 at 20:19

That mouthful sounds like "cepacol"antiseptic mouthwash:D

I'd bet that surfactant spreader-sticker wetting agent which is added to water based sprays of fungicides and fertilizers would also work . I think it is a polyoxyethylene
type and is also a non foaming emulsifier .

I don't think titanium will survive unless it is platinum plated .

And the way in which the PbO2 is deposited , the electrolyte additives , the temperature and current
density are all quite specific to obtaining the adherent
type of PbO2 allotropic modification which has structural
integrity ....just any old PbO2 won't cut it and will always
disintegrate . The PbO2 must have a very specific
crystalline structure . That is what the patents on PbO2
anodes are really all about , the art of growing electrodeposited crystals of a specific sort of PbO2 that is dense and durable . The nickel is important I think ,
and fluoride is used too although I am not certain it is essential .

Attachment: US2945791 GSLD anode.pdf (575kB)
This file has been downloaded 947 times

hashashan - 25-3-2007 at 14:03

Well i don't know if thats the best place for it but
i managed to plate PVC with PbO2 using the geocities method. But a weired thing happned
as soon as i started the electrolysis a brown cloud misted the whole vessel. the current is kept on 6A and the voltage is 5V.
Is the cloud something i should worry about or is it there just because the anode is new?
Also can i raise the voltage to 12V, just want to speed up the process, i dont want to wait a month :(


PS. i started my electrolysis from raw NaCl and not chlorate.

hashashan - 26-3-2007 at 07:03

Well my electrode failed .. for some reason it cracked swollowed and disintegrated :(
I will try to make the cloth reinforced eletrode today
also ive seen its possible to use titanium as substrate ... how do you do that?

dann2 - 30-3-2007 at 13:41

Hello,

Sad to see the Anode fail. What did the coating look like. Was it a fearly good coating? Was it continous and hard?
Are you sure you are using a DC voltage connected the right way around in your Chlorate cell?. A brown cloud forming immediatly almost sounds like you had the Lead Dioxide connected to the minus.

Using Ti is not so simple as far as I can make out. You need a coating of Platinum on the Titanium first or the Anode will fail because Ti Oxide will eventually form between the Lead Dioxide and the Ti metal.

These's Lead Dioxide Anodes have not been so simple as it sound to make. I have always though that there was potential for the 'Cloth substrate' Anodes. I make some of them. I use one of them for about two weeks in a cell untill it got eaten away. It was a very thin Anode. It did not crack or fail suddenly, simply slowly got thinnner which I thought was a good sign. I give some of them to another guy to try out but never heard anything back.
They can be difficult to get the plating to start. You will have to run a small current for quite some time before the 'pasted cloth' will be able to carry a good plating current for to build up the Anode.

Keep us posted.

Dann2

hashashan - 1-4-2007 at 02:01

I am currently electrolyzing with a cloth reinforced anode i made.
no signs of erosion at all.
I plated it on scotchbright if there is such a thing where you live. Its a plastic cloth made to rub things in order to clean them.
plated for 3 days on it and now the electrolisys is going well for 3 days already.
however the conection to them is a bitch, i didnt use the silvering method and there is quite a lot of resistance on the conections.

dann2 - 1-4-2007 at 16:11

Quote:
Originally posted by hashashan
I am currently electrolyzing with a cloth reinforced anode i made.
no signs of erosion at all.
I plated it on scotchbright if there is such a thing where you live. Its a plastic cloth made to rub things in order to clean them.
plated for 3 days on it and now the electrolisys is going well for 3 days already.
however the conection to them is a bitch, i didnt use the silvering method and there is quite a lot of resistance on the conections.


Nice one!!

I believe the 'cloth' you are using is familar to me.
It is really a matt of plastic, some mm's thick and very porous?
How thick was the cloth (or pasted cloth) when you started to plate?
How thick was it when you were finished plating?
What did you use as a connection to the cloth as you were plating?


Silver is the best by far connection to Lead Dioxide as this article describes.

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...

The substrate Anodes have their Graphite or (Pt plated) Ti to do the job.

Any chance of some pictures.
Keep up the good work.

Cheers,
Dann2

dann2 - 1-4-2007 at 16:29

Oh dear, I'm answering my own posts!!!!!!!!!

There is silver conductive paint on ebay if you are interested.

http://cgi.ebay.co.uk/Conductive-Silver-Paint-Fix-Repair-Fau...

I used 'silver conductive paint' as the search string.

You should be able to get something similar for mending the heaters on back windscreens of cars in your local car accessory shop.

IF there is alot of heat at the connection the Anode will prematurly fail. IMHO

hashashan - 2-4-2007 at 13:10

Well the cloth was about 3mm thick and it didnt get any thicker however it is now fully coated inside its like a single 3mm thick piece of PbO2... very stiff.
the connection at the moment is just a piece of graphite clamped to the end and i manage to get about 5 amps with this conection.
hoever the weired thing that i already electrolized twice the time needed and no perch formed :(
ill continue for a few days and we'll see.
about the pictures the best thing i can do is with my cell phone.
but ill try to upload some good pics if the whole process will be successfull.
i dont know where to get the silver paint and i ddint understand what youve said about the back windscrrens
she shipment to israel of the paint will cost me like a piece of Pt and i just dont see any reason. i want it to be DIY.
for now no signs of corrosion if i wont count the first brown cloud appearing, I think its just because its the first time and some of the coating wasnt good, but bo signs on the electrode itself.

dann2 - 2-4-2007 at 16:43

Quote:
Originally posted by hashashan
Well the cloth was about 3mm thick and it didnt get any thicker however it is now fully coated inside its like a single 3mm thick piece of PbO2... very stiff.
the connection at the moment is just a piece of graphite clamped to the end and i manage to get about 5 amps with this conection.
hoever the weired thing that i already electrolized twice the time needed and no perch formed :(
ill continue for a few days and we'll see.
about the pictures the best thing i can do is with my cell phone.
but ill try to upload some good pics if the whole process will be successfull.
i dont know where to get the silver paint and i ddint understand what youve said about the back windscrrens


Hello,

The back windows of cars have a heater in them to stop condensation from forming on the window. The heater can be seen as horizontal lines in the glass. Sometimes one of the lines brake and the heater will not work in the area of that line, giving condensation on the window. Silver conductive paint can be used to repair the line in the glass by simply repainting the line in the window. This silver paint is sometimes supplied by car accessory shops (Automotive factors they are sometimes called over here). The paint contains Silver metal.
Picture of box here:

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...


How big is the cell and how much current are you running into it.
Is it NaCl03 or KClO3 you are using.
How do you know that no Perchlorate has formed.
Is your power supply stabalized or is it a more crude device.

Cheers,
Dann2

Alembic - 3-4-2007 at 12:10

Quote:
Originally posted by dann2
<snip>
Using Ti is not so simple as far as I can make out. You need a coating of Platinum on the Titanium first or the Anode will fail because Ti Oxide will eventually form between the Lead Dioxide and the Ti metal.

These's Lead Dioxide Anodes have not been so simple as it sound to make. I have always though that there was potential for the 'Cloth substrate' Anodes. I make some of them. I use one of them for about two weeks in a cell untill it got eaten away. It was a very thin Anode. It did not crack or fail suddenly, simply slowly got thinnner which I thought was a good sign. I give some of them to another guy to try out but never heard anything back.
They can be difficult to get the plating to start. You will have to run a small current for quite some time before the 'pasted cloth' will be able to carry a good plating current for to build up the Anode.

Keep us posted.

Dann2


I have had some success with PbO2 Ti anodes. (Do a search for my old posts if you would like to see a picture). I have tried *many* substrates before that (carbon from batteries, pure graphite as well as ceramic) in the distant past but came to the conclusion that Ti is the most suitable.

BTW, the dimensions of the anode in the picture are 5cm x 30cm.

The process that I finally settled upon is a bit laborious but I have had pretty consistent results:

I used Ti sheet of about 1mm thickness because that is waht I had at the time. A little thicker would probably be better.

The first step involves drilling the solid sheet full of small holes. I used a piece of perforated stainless as a drilling guide/pattern. The holes then need to be de-burred or slightly countersunk to get rid of the ragged edges left by the drilling step; I just used a larger diameter drill bit to do this.

The substrate should then be sandblasted, (to help the PbO2 adhere to it. The holes are needed for the same reason) degreased with dishwashing soap, thoroughly rinsed in clean water and dried.

Next, a semiconducting coat of Sb doped SnO2 was applied by painting on a solution of SnCl4 + SbCl3 in water + butanol, drying, and then heating to 500 degrees Celsius or so in an oxidizing atmosphere i.e. air. This step was repeated five to ten times to give a suitable coating thickness. I will try to find the patent that describes this.

Then a thin (about 0.1mm) layer of alpha PbO2 was plated onto the substrate from a alkaline lead tartrate bath. See pat. GB 850,830 for info.

The final coat of beta PbO2 was then plated over top of this from a lead nitrate bath, also described in GG 850,830
This layer was about 2mm thick.

The anode performed well in a perchlorate cell.

-Alembic

hashashan - 3-4-2007 at 14:06

Quote:
Originally posted by dann2
Quote:
Originally posted by hashashan
Well the cloth was about 3mm thick and it didnt get any thicker however it is now fully coated inside its like a single 3mm thick piece of PbO2... very stiff.
the connection at the moment is just a piece of graphite clamped to the end and i manage to get about 5 amps with this conection.
hoever the weired thing that i already electrolized twice the time needed and no perch formed :(
ill continue for a few days and we'll see.
about the pictures the best thing i can do is with my cell phone.
but ill try to upload some good pics if the whole process will be successfull.
i dont know where to get the silver paint and i ddint understand what youve said about the back windscrrens


Hello,

The back windows of cars have a heater in them to stop condensation from forming on the window. The heater can be seen as horizontal lines in the glass. Sometimes one of the lines brake and the heater will not work in the area of that line, giving condensation on the window. Silver conductive paint can be used to repair the line in the glass by simply repainting the line in the window. This silver paint is sometimes supplied by car accessory shops (Automotive factors they are sometimes called over here). The paint contains Silver metal.
Picture of box here:

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...


How big is the cell and how much current are you running into it.
Is it NaCl03 or KClO3 you are using.
How do you know that no Perchlorate has formed.
Is your power supply stabalized or is it a more crude device.

Cheers,
Dann2


I am running the cell from NaCl and i know that no perch formed because i probed the stuff. I dropped in KCL solution and nothing crystallized.
The cell ran at about 5-12 amps on a PC PSU.
Ill wait a few more days.

BTW, There are a lot of salts climbing up the anode and setteling on the contact. White salts, What are they?

dann2 - 3-4-2007 at 14:52

Hello Alembic,

Anode looks good!!

Some holes are visible at the top of the Anode. Are the size and density of theses holes a representation of all the holes that you put into the Ti.

Anode is here:
http://www.sciencemadness.org/talk/viewthread.php?tid=1425&a...

Have you used the Anode for many hours.

Could it be ok if I put your method on a web page.

You sound a lot like a guy I used to communicate with about Lead Dioxide Anodes etc from Canada. His first initial was J.
Perhaps you ARE that guy :)

Will read patent. The two baths sounds like a lot of trouble, but perhaps I am lazy.
Did you ever try coating with Beta (Lead Nitrate bath) only, on top of Sn/Sb coat?
Perhaps you don't give into cutting corners :D

Cheers,
Dann2

Some info on Alpha and Beta Lead Dioxide here:

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...

dann2 - 3-4-2007 at 15:08

Quote:
Originally posted by hashashan






I am running the cell from NaCl and i know that no perch formed because i probed the stuff. I dropped in KCL solution and nothing crystallized.
The cell ran at about 5-12 amps on a PC PSU.
Ill wait a few more days.

BTW, There are a lot of salts climbing up the anode and setteling on the contact. White salts, What are they?


Hello Hashashan,

You are not measuring the current very accurately
:D
I would be very supprised if you do not get Perchlorate eventually. You probably need to run the cell for longer.

The salts will be a mixture of what is in the cell. NaCl, NaClO3, and NaClO4 when it begins to form. (and some KCl too!)

Are the salts climbing up the Anode on the outside of the Anode or are the salts climbing up the Anode in the interior (inside) of the Anode?
If the Anode is porous (not solid) the salts will climb up inside the Anode and will be very hard to stop.
If the salts are simply climbing up the outside of the Anode this is easy to stop by better sealing the Anode into the lid of the cell.

There is a rant about Anode sealing here:

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...

Posyester {edit: thats Polyester} resin (purchase in car accessory shop) is great for sealing Anode into lid.

How big is the cell.

Cheers,
Dann2

[Edited on 4-4-2007 by dann2]

dann2 - 3-4-2007 at 15:51

pat. GB 850,830 for info.


Hello,

I think the patent number is incorrect.

Dann2

Alembic - 3-4-2007 at 16:00

Quote:
Originally posted by dann2
pat. GB 850,830 for info.


Hello,

I think the patent number is incorrect.

Dann2


Oops! I guess I'm somewhat dyslexic today! :P The right number is GB850380. Sorry for the confusion.

-Alembic

hashashan - 3-4-2007 at 21:46

Quote:
Originally posted by dann2
Quote:
Originally posted by hashashan






I am running the cell from NaCl and i know that no perch formed because i probed the stuff. I dropped in KCL solution and nothing crystallized.
The cell ran at about 5-12 amps on a PC PSU.
Ill wait a few more days.

BTW, There are a lot of salts climbing up the anode and setteling on the contact. White salts, What are they?


Hello Hashashan,

You are not measuring the current very accurately
:D
I would be very supprised if you do not get Perchlorate eventually. You probably need to run the cell for longer.

The salts will be a mixture of what is in the cell. NaCl, NaClO3, and NaClO4 when it begins to form. (and some KCl too!)

Are the salts climbing up the Anode on the outside of the Anode or are the salts climbing up the Anode in the interior (inside) of the Anode?
If the Anode is porous (not solid) the salts will climb up inside the Anode and will be very hard to stop.
If the salts are simply climbing up the outside of the Anode this is easy to stop by better sealing the Anode into the lid of the cell.

There is a rant about Anode sealing here:

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...

Posyester resin (purchase in car accessory shop) is great for sealing Anode into lid.

How big is the cell.

Cheers,
Dann2

The anode is quite small about 4*6 cm, the cell is a 2 mole sell.
And i know im not measuring the current very acurately , thats because the cerll is just experimental to check if the anode will last at all.
The salts are from the outside.
Today a weired thing happned, a chunk of the anode just got eaten away and the curent dropped to 0.6 A,
I rewired the whole thing and now the cell is running at about 3-4 amps(quite a drop)
does the current drop when the NaCl is getting low?
does the current drop at any stage?

Alembic - 4-4-2007 at 03:34

Quote:
Originally posted by dann2
Hello Alembic,

Anode looks good!!

Some holes are visible at the top of the Anode. Are the size and density of theses holes a representation of all the holes that you put into the Ti.

Anode is here:
http://www.sciencemadness.org/talk/viewthread.php?tid=1425&a...

Have you used the Anode for many hours.

Could it be ok if I put your method on a web page.

You sound a lot like a guy I used to communicate with about Lead Dioxide Anodes etc from Canada. His first initial was J.
Perhaps you ARE that guy :)

Will read patent. The two baths sounds like a lot of trouble, but perhaps I am lazy.
Did you ever try coating with Beta (Lead Nitrate bath) only, on top of Sn/Sb coat?
Perhaps you don't give into cutting corners :D

Cheers,
Dann2

Some info on Alpha and Beta Lead Dioxide here:

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...


The holes were about 2.5mm and yes, you can get some idea of the density of those holes from the picture.

That specific anode was only used for two batches of perchlorate, starting from NaClO3, which means that is has seen about 200 hours of use at a current of 35-40 A. It still looks pretty much exactly the same. I have made other anodes (using the same process) that I've used in chlorate cells for hundreds of hours with no visible signs of wear.

You can put my method on your web page if you want. I'm also pretty sure we've communicated before since I just happen to be from Canada and my first initial also happens to be J. ;)

The alpha PbO2 layer was added in order to improve adhesion + uniformity of the final beta PbO2 layer. See US5683567 for a description of a very similar anode.

I used to always try and cut corners but after accumulating a whole lot of hazardous waste from failed attempts I've come to realize that it is easier to do it properly, even if it is more work.

-Alembic

dann2 - 4-4-2007 at 14:19

Quote:



The anode is quite small about 4*6 cm, the cell is a 2 mole sell.
And i know im not measuring the current very acurately , thats because the cerll is just experimental to check if the anode will last at all.
The salts are from the outside.
Today a weired thing happned, a chunk of the anode just got eaten away and the curent dropped to 0.6 A,
I rewired the whole thing and now the cell is running at about 3-4 amps(quite a drop)
does the current drop when the NaCl is getting low?
does the current drop at any stage?


It would be near impossible if not totally impossible to tell the concentration of NaCl in the cell by observing what the current is. IMHO
The Voltage accross Perchlorate cells is generally higher in industry but the main reason why the Voltage is higher is because the Anodes are driven at a higher current density and the cells usually have a lower volume to current ratio when compared to Chlorate cells. The higher current densities and the lower volume to current ratio are decisions made by the manufacturers for economic reasons that don't really concern the home Perhlorate maker.
Higher current densitys and lower volume to current ratio are NOT essential (when compared to Chlorate cells) when making Perchlorate. If you were going to make a few tons per day then it would be very very wise to have cells running at high current densitys etc for economic reasons.

I do not think that the current will drop any significant amount at any stage during the manufacture of Chlorate .....to ....Perchlorate.
It would be an interesting experiment to put an accurate current meter into the circuit, using a voltage stabalized supply (Computer supply would be good) and logging/observing how the current varies as the process proceeded. You would need to keep the cell temperature and the level of electrolite steady.

Cheers,

Dann2

dann2 - 4-4-2007 at 14:38

Quote:
Originally posted by Alembic

The alpha PbO2 layer was added in order to improve adhesion + uniformity of the final beta PbO2 layer. See US5683567 for a description of a very similar anode.

I used to always try and cut corners but after accumulating a whole lot of hazardous waste from failed attempts I've come to realize that it is easier to do it properly, even if it is more work.

-Alembic


Hello Alembic,

The whole "Lead Dioxide Anode thing" is littered with noble but failed attemps at getting long lasting anodes that can be made at the back of a ditch (as we say over here), for next to nothing, with hardware store chemicals :)
The proper way seems to be the only way!

I am experimenting with a Magnetite Anode at the moment. The current effeciency seems to be HOPELESSY low.

Do you recognise this. You wrote method one :-)

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...

It's good to meet and hear from you again. You were always a DAMM GOOD source of information and conversation.

Cheers,
Dann2 (formerly Dann1..... formerly..........)

Bismuth modified , erosion resistant PbO2

Rosco Bodine - 5-4-2007 at 00:31

This could be useful information , and I don't recall seeing it posted before . Evidently the co-plating of a controlled amount of bismuth peroxide with lead peroxide forms a
harder and denser , much more erosion resistant PbO2
anode which also operates at better current efficiency .
This is only useful in a limited thickness because cracking problems develop with heavier layers . It might be possible to build up a thicker anode using cloth wrap or intermediate layer reenforcement as was mentioned earlier in this thread .

The patent also describes an interesting improvised flow through coaxial electrode which was used for one of the experiments , where the electrolyte is pumped through
the electrode assembly .

[Edited on 5-4-2007 by Rosco Bodine]

Attachment: US4101390 Bismuth modified thin layer Lead Dioxide Perchlorate Anode.pdf (977kB)
This file has been downloaded 1858 times

mxy520 - 5-4-2007 at 19:58

hehe ,i am from china
i first in it ..
my please

hashashan - 7-4-2007 at 05:00

dann, i couldn't find any silver paint for a good price since i missed that ebay bid.
So i am looking for other methods.
Can silver be electrodeposited on the PbO2 anode? and how should it be done?
Are there other metals that can be electrodeposited on it (not Pt).
How about a good graphite connection, is it possible? maybe grapite coated with PbO2, it wont be immersed into the electrolyte so it wouldn't corrode away, am i right?

dann2 - 7-4-2007 at 09:31

Hello Hashashan,

You could try very Silver powder mixed with a solvent. Or silver wire wrapped around the anode. You will find a link to Silver plating here:

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...


Below is more silver paint on ebay. It will cost a lot less that starting to electroplate silver.



http://search.ebay.co.uk/search/search.dll?from=R40&sati...

dann2 - 7-4-2007 at 10:15

Quote:
Originally posted by Rosco Bodine
This could be useful information , and I don't recall seeing it posted before . Evidently the co-plating of a controlled amount of bismuth peroxide with lead peroxide forms a
harder and denser , much more erosion resistant PbO2
anode which also operates at better current efficiency .
This is only useful in a limited thickness because cracking problems develop with heavier layers . It might be possible to build up a thicker anode using cloth wrap or intermediate layer reenforcement as was mentioned earlier in this thread .

The patent also describes an interesting improvised flow through coaxial electrode which was used for one of the experiments , where the electrolyte is pumped through
the electrode assembly .

[Edited on 5-4-2007 by Rosco Bodine]


Hello,

It is interesting to note that they only mention in the patent (page 6 lines 10 to 15) very brifely that it may be needed to coat the substrate with Pt or some of its oxides. You would think they were trying to hide the fact................

Cheers,

Dann2
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