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dann2
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@Vikascoder
How long has the Anode worked in a Perchlorate cell.
What size is the Anode.
What current do you drive into it.
Have you a camera that you know how to operate or do you have any friends with cameras that know how to operate them.
Attached is some more blow by blow by blow by blow stuff from running my LD Anode.
It is starting to show it's age at the bottom by crumbling away. I thought it would last much longer.
The messing around with the Chloride/HCl acid did not help I guess. I often wonder how Platinum would hold up in a Perchlorate cell under similar
conditions.
Dann2
Attachment: ld_130.zip (193kB)
This file has been downloaded 843 times
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quicksilver
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Quote: Originally posted by Griffin  | Hello,
Sorry if this is a stupid question. Are there companies that manufacture PbO2 anodes?
Many thanks |
This has only been MY experience....
If you do a search, you'll find a few. They are seriously expensive. One company is in Ireland & they mfg a professional quality set. There was a
company in China that had them but someone I know gambled & was very disappointed with it (it appeared homemade and was simply not worth the money
in terms of it's performance or quality).
The only seriously real method is to join a "business to business" contact site (and actually HAVE a business license) & go in with someone or
several more people and buy some. Buying as an individual is like buy chemicals from United Nuclear: it's not a very good deal....
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dann2
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Hello,
Been runnin me ould Anode for close to 6 months now. It's getting rather delapidated looking but still going strong (at a much reduced surface area
and current).
Added some more details to the end of this page:
http://www.oxidizing.110mb.com/chlorate/leaddiox/mmold.html
I obtained some very nice looking Sodium Perchlorate crystals on run 8 when the cell cooled down. I got similar shards on previous cell runs too.
Dann2
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dann2
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Anode has reached the end of it's life.
Added some more to the file.
http://oxidizing.110mb.com/chlorate/leaddiox/mmold.html
Going to wake..........
BLESSED BE THE DIAMOND SHAMROCK PATENTS AND ALL THEIR WORKS!!!!!!!!!!!
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Swede
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Hi dann2, I finally caught up with your research. You've done some excellent work. I wanted to thank you for adding so much to the body of
knowledge.
I find it very interesting that your LD anode exhibited nearly identical edge warts to mine, and that the failure mode was also nearly identical...
the warts fell off where the LD was plated over bare edge Ti, no MMO.
The conclusions that I took from that page you posted was that additions of acid seemed pointless, and that HCl may actually be harmful. Chlorides =
erosion? So the optimum bath for LD would consist of chlorates with minimal chloride. The notion of taking a 100% chloride solution to perchlorate
via LD seems to be a pipe dream.
One other thought - thick LD coatings may actually be LESS desirable than thin. The anode seemed to self-destruct in chunks, with the thicker
sections simply being shed in their entirety. Perhaps a thin LD coating will have less internal stresses, and would last longer.
Once a LD plating bath is set up, maybe the way to go would be to plate multiple anodes at a time (or sequentially) with a lighter coat, and when the
smoke clears, the user would have half a dozen (or more) LD anodes.
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dann2
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Hello Swede,
Accounts of making and using homemade LD Anodes for making Perchlorates (and Chlorates ) are not too plentiful.
Accounts of using LD Anodes, made by companies (professionally made Anodes) are practically non existent. The only account I know of is on APF with
only some very sketchy details + no pictures that you can actually see anything useful in. So I wonder do those professionally (Chinese) made Anodes
last for months in a cell?
When running my last LD Anode, I decided to spent quite a bit of time (perhaps too much) running Sodium Perchlorate cells with only small amounts of
Chlorate in them as I wanted to get some knowledge of how the Anode performed in this region. This region is interesting from an Amateurs point of
view as it is really a Perchlorate purification process that circumvents a re-crystallizing step. This way gives very very low CE.
If large amounts of Perchlorate are the target, then a higher CE route would be much better by keeping cells at a high Chlorate concentration (and a
very high Perchlorate concentration) and taking solid Sodium Perchlorate from the cell. If I had run the MMO substrate Anode at a high Chlorate
concentration a total of approx. 33KG of Perchlorate (from Chlorate) would have been produced over
the lifetime of the Anode. This particular MMO substrate Anode give very low CE even when Chlorate concentration was high. I blamed having Red Lead in
the plating tank though that’s only a guess.
Making K Perchlorate directly from K Chlorate is interesting is it avoids the Na contamination. Your own account is the only one that I know of.
As you stated when you have gone to the trouble of setting up an LD plating rig it would be wise to make a number of Anodes. But then again you have
to ask yourself just how much Perchlorate do you want/need.
There is still much to be learned. I wonder how the original poster of the LD on Titanium Anode managed to get such a smooth, well defined coating of
LD (picture below). I think perhaps surfactant may help.
I have bailed out of the Anode scene for a while.
Dann2
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plante1999
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I finally make a working PbO2 anode!!!
I made a working PbO2 anode! To make it I took about 13g of lead II oxide and some ammonium nitrate (The lead oxide was in excess) And added about
40ml of water and boiled the solution to make lead nitrate and ammonia. Then I filtered in 3 coffee filter and I got a clear-yellowish sol., I tested
for lead by pouring some of the sol. in sodium sulphate, the test was positive.
2NH4NO3 + PbO -) H2O + Pb(NO3)2 + 2NH3
Then I took a clean mmo mesh of 1inch by 4 and a similar titanium cathode and added them in the lead nitrate sol. (mmo mesh as the anode). I
electrolysed it with 3.3V dc (1 inch by 1 inch surface area each) for an hour, There was a lot of spongy lead at the cathode but then I attempted to
clean the anode(The plating on the anode was really black, much more than the gray mmo coating.) with conc. HCl but I destroyed about 3/8 inch by 1/4
of the plating making insoluble lead chloride and chlorine gas... Then I attempted to repair my fault by running the anode again in the lead nitrate
bath but only a very thin layer formed and the electrolyte was not conductive anymore. Then I run it at 3.5V in conc. NaCl sol. for 2 hour, there was
some lead oxide in the solution and the destroyed plating which I repaired was destroyed again (I suppose the plating was too thin). I poured some
clean electrolyte and cleaned the cell/electrodes and I tested it again for 10 hour, there was not lead oxide precipitate and the very black coating
was still there, success! Now I'm testing its durability by electrolising it at 6V 9 amp for 10hour, if the anode is still intact it will prove that
the coating is very good, and that you don't need fancy salt to make lead dioxide anode. only lead nitrate and mmo mesh and you could make lead
dioxide anode.
I never asked for this.
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dann2
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I love the idea of making Lead Nitrate from Lead Oxide (Litharge) and Ammonium Nitrate!
Would boiling Lead Dioxide (from an old car battery) and Ammonium Nitrate convert the Dioxide to Lead Nitrate if you were to boil for long enough I
wonder.
Lead Dioxide is insoluble but if you boiled for long enough (simmer for a few days perhaps) the Lead might eventually all leach out with Lead Nitrate
becoming the only thing left in solution.
Perhaps adding some Hydrogen Peroxide might help. I do know that Hydrogen Peroxide + Nitric acid will dissolve (react) with Lead Dioixide.
Dann2
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plante1999
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| Quote: Originally posted by dann2 |
I love the idea of making Lead Nitrate from Lead Oxide (Litharge) and Ammonium Nitrate!
Would boiling Lead Dioxide (from an old car battery) and Ammonium Nitrate convert the Dioxide to Lead Nitrate if you were to boil for long enough I
wonder.
Lead Dioxide is insoluble but if you boiled for long enough (simmer for a few days perhaps) the Lead might eventually all leach out with Lead Nitrate
becoming the only thing left in solution.
Perhaps adding some Hydrogen Peroxide might help. I do know that Hydrogen Peroxide + Nitric acid will dissolve (react) with Lead Dioixide.
Dann2 |
In fact my PbO was from calcined car battery PbO2, heated to 400 degree C PbO2 will decompose prety fast to PbO, I recommend to do this in a steel
container. It was prety easy to make. My anode plating still look nice and does not passivate. I will run it from chloride to perchlorate. I will test
with methylene blue after.
[Edited on 31-5-2012 by plante1999]
I never asked for this.
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Swede
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@dann2 - I've used surfactants, and I think they may help. I still have that LD anode I made long ago, and except for the edge nodules shedding, it
still looks as good as the day I made it. But I have not subjected it to the intense testing you did to your own. I really need to push it a bit to
see if the process does in fact make a durable LD over MMO anode.
In the picture you posted, if I were to guess, the substrate has a pattern of holes drilled in it. See how the LD coating has those regular dimples?
When I plated my mesh, I was hoping to close the mesh holes, but that proved overly optimistic. With smaller holes, the lead dioxide would fill the
holes and mechanically join both sides. Passivation of the substrate may be inevitable, but if slow enough, there may be enough contact between
substrate and coating to allow the anode to last a very long time.
plante, I'm glad you are seeing some success. The big question (as always) is the durability of the anode when producing perchlorate. Any trials
yet?
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dann2
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Hello Swede,
Yes, the dimples are where the holes were in the Ti.
Its a fairly thin piece of Ti that was used.
The original post for the Anode is here:
http://www.sciencemadness.org/talk/viewthread.php?tid=1425#p...
With a description thus: (I think I got this by U2U)
(In relation to the Anode)
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 what 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 dish-washing 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°C or so in an oxidizing atmosphere i.e. air. This step was repeated five to ten times to give a suitable coating thickness.
Then a thin (about 0.1mm) layer of Alpha PbO2 was plated onto the substrate from an alkaline lead tartrate bath.
The final coat of beta PbO2 was then plated over top of this from a lead nitrate bath. This layer was about 2mm thick.
The Anode performed well in a perchlorate cell.
The Anode above was only used for two batches of perchlorate, starting from NaClO3, which means that it 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.
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.
I chose the SnO2/Sb2O3 system because it is easy to apply and the raw materials are easy to come by and above all cheap. SnO2 also has a higher Oxygen
overvoltage than PbO2 which supposedly means that any exposed SnO2 will not interfere with the Anodic formation of Perchlorate.
____________________________________________________-
In relation to passivation of the substrate it may not be that serious after all.
I guy on a different forum has simply bolted a piece of Ti to a platinum anode and put the anode + connection into a cell and it workes OK. I have
done the same thing with MMO and a Titanium runner (connection) and it seems to work OK. It's as if the current is able to 'jump' a small gap + the
Ti Oxide once the connection is under the surface of the electrolyte. The surface of the connection where it matters (beside the Anode material
proper) seems to act almost like a cathode and the surface layer of Ti Oxide which is usually a good electrical insulator becomes conductive (by the
hydrogen released in the vincity) just like when Ti is used as a cathode.
It's described in a paper posted here somewhere or other. The released hydrogen dopes the normally insluating Ti Oxide and it becomes conductive.
Some of the Anode pictures that I posted show pieces of LD literally hanging off the substrate yet they seem to go on working (passing current into
the electrolyte) until they fall off completely.
Dann2
[Edited on 15-6-2012 by dann2]
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Swede
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I know we've flogged this to death in various threads. We repeat ourselves over the years and go in circles, but it's hard not to.
I think the answer (for garage PbO2) will ultimately be a simple one, and I suspect it'll involve unique anode geometries, moreso than polymers or
other compounds designed to give the correct PbO2 both structural integrity AND continuous conductivity with a suitable substrate. That is where I
was going with the holes.
Perhaps a Ti substrate can be constructed such that the PbO2 is not hanging on for dear life, but is instead compacted into chambers or holes. Like a
honeycomb... the Ti is the wax, and the PbO2 is the honey. Simplistic, but you get the idea. Of course, when you plate something like that, the
fastest buildup is in areas where you wouldn't ultimately want it, rather than the voids.
Maybe mechanical intervention during the plate process? A scraper periodically over the horizontal surface... buildup is allowed only/primarily in
the voids.
Of course, correct prep of the substrate will always be a factor, and if not done, it'll simply shed or passivate so badly that no current will flow.
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Swede
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Follow up thought - start with a sheet of Ti, 6mm thick or so. Spray the sheet with some sort of resist... a lacquer of some sort, so as to prevent
electrical contact with the lead salts bath. Drill a pattern of holes in the sheet to form the honeycomb chambers. Chemically prep/etch the chambers
so as to receive the plating. Plate away... the voids fill with PbO2, the faces do not, and you end up with an anode that is mechanically sound, at a
minimum. If the Ti / PbO2 junction does not passivate, then it might be practical.
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dann2
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It is difficult to get PbO2 to plate into deep (ish) holes or into (inside) corners. The outside rim of the hole will plate first and plug the hole
IMO.
I think myself the garage PbO2 Anode HAS arrived. Its PbO2 on MMO!!!
The original poster of the Ti substrate anode (pictured above) said that the anode has done many many hours. It may not look so good after many
months?
I am not knocking his Anode saying this. These things only have a certain life time.
Perhaps an improvement can be made by incorporating a fine reinforcing mesh, like the guys doing the massive anode, wrapped around the MMO mesh.
Hashashan used stuff for domestic pot cleaning. PVC I presume it was made from.
BTW the anodes I made last time had very low CE for some reason or other. I am not too sure why.
Dann2
[Edited on 15-6-2012 by dann2]
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Swede
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It is interesting... quite a few PbO2 anodes being offered from China on Alibaba and similar sites look very similar to those we have produced in our
labs.
These vendors also discuss some of the technical aspects of PbO2, such as recommended current density, conductivity, and application notes.
PbO2 anodes on Alibaba
Check out some of the pictures... edge warts and all. I wonder if these commercial anodes are truly superior to those we have made, or if they are
simply used as a replaceable commodity with a fixed life?
In retrospect, the challenging part of plating PbO2 is in the setup. As I believe I mentioned earlier, once a respectable plating system is set up,
the way to go would be to plate a half dozen anodes in succession, obviously keeping track of the bath constituents. A plating bath of respectable
volume would be more expensive and troublesome, but would be chemically more stable, and capable of generating multiple anodes over the course of a
plating session.
[Edited on 26-6-2012 by Swede]
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dann2
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Hello Swede,
They don't seem too warty to me, but then again the photos are not up real close.
This one (its one with six connections going to the same anode or is it two anodes on top of one another?)
http://baojichangli.en.alibaba.com/productshowimg/494839933-...
seem to have pieces of thread coming out of it. I wonder what that is. fIber reinforcing perhaps?
Regarding tank size, you can work with quite modest tank volumes and use a pump to keep pumping in neutral Lead Nitrate. A simply peristaltic pump is
OK.
Tank size I used last time was about 1 liters and one liter in neutral tank with the solution and could go on for ever IMO. Just keep adding Lead
Carbonate and some Copper carbonate if blue colour gets weak.
I will look up an article on Graphite substrate anodes. I think they lasted an average of X months (5mm thick PbO2 coat).
edit:
Looking at some articles here and here
The first link states:
The anodes gave satisfactory service for 24 months
with 50% of the anodes still in good condition. A current
efficiency of 70-80% was obtained while depletin
See table 4 in the second link.
To make a long story short LD anode don't last for ever. Though if I made some with Graphite substrates and they lasted that long I would be happy.
But you might always got a bad one.
Thats the advantage with Ti. Even if you get a 'bad' one it will run and run.
The guys in china probable have access to custom pieces of Ti coated with MMO all over. They are not cutting MMO and having problems with the 'ends'
not being coated with MMO. They even seem to have end edges of some of the anodes reinforced with flat Ti strips or some such.
[Edited on 27-6-2012 by dann2]
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tomasbrod
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Anode
I have a problem with plating PbO2 on graphite substrate. I started with lead copper vinegar sodium bicarbonate lathern batteries 500uF capacitor
diode and 4-6V AC power supply. I made sodium acetate solution put lead and copper strips in it and connected lead to positive and copper to negative
4-6V 300mA. Gray precipitate of Pb(OH)2 filtered after a day. Repeated until half of lead strip eroded. Some lead plated on copper so my Pb(OH)2 was
contaminated with lead(0). Then i replaced remainder of lead strip with copper wire. Again repeated until anode eroded out. I neutralised Pb hydroxide
with vhite vinegar and it bubbled. Light blue copper hydroxide not bubled when neutralising, but dissolved after a while. Both acetates crystalised on
sun. Lead acetate - nice cristals. Copper acetate - samll crystals with white and brown contamination. I put coiled copper wire in a beaker. Then
dissolved 1:3 by volume of both acetates in the beaker. I opened a lathern battery and get graphite electrode 7mm in diameter. I sanded the electrode.
I attached a copper wire on top and put in centre of the beaker. Hooked wires and turn on power. Set current to 15mA. Added drop of dish
soap(surphacant). A bit plated but then bubbles started forming on anode. No bubbles on cathode instead nice small lead crystals formed. Is there any
way to prevent the bubbles?
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hissingnoise
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Preparation of graphite-substrate lead dioxide anodes, improved method!
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Swede
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This is weird... I was browsing yet again for PbO2/perchlorate info and ran into a paper published in an Iraqi science journal. As I read it, I'm
thinking "I've read this before. I'm positive."
I found the article it in the "Diyala Journal of Engineering Sciences", vol 2, No. 1, June 09. Does the following ring a bell with anybody? I
believe the real author to be a member here...
Here is the text, supposedly by one Ahmed D. Wiheeb. The article (a PDF) can be found Here.
From "Mr. Wahib's" paper:
| Quote: |
DSA stands for Dimensionally Stable Anode. This is the common term used to refer to anodes consisting of a layer of noble metal oxides (usually RuO2
and TiO2) coated onto a substrate, usually titanium. This type of anode is finding increased use in industrial cells because of its comparatively low
cost when compared to platinum and its resistance to corrosion. The chemicals required to manufacture these anodes are expensive and difficult to
handle. However, if the chemicals can be obtained and suitable equipment is available, the procedure to make the anode seems fairly straightforward
and may be an option
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The exact same text, as well as the bulk of the guy's "paper", can be found here.
| Quote: |
DSA: DSA stands for Dimensionally Stable Anode. This is the common term used torefer to anodes consisting of a layer of noble metal oxides (usually
RuO 2 and TiO 2 )coated onto a substrate, usually titanium. This type of anode is finding increased use inindustrial cells because of its
comparatively low cost when compared to platinum and itsresistance to corrosion. The chemicals required to manufacture these anodes areexpensive and
difficult to handle. However, if the chemicals can be obtained and suitableequipment is available, the procedure to make the anode seems fairly
straightforward andmay be an option. For the preparation of these, the reader is referenced to the literature.Again, I'd be most interested in
anyone’s experiences with this type of anode
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Again, didn't someone here write this stuff? Dann2, is this your text? The guy ripped someone off with a blatant cut and paste job for the "theory"
section of his article. Wow...
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Swede
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Follow up: In an attempt to get back on topic, I did find an excellent article that explained one question that had been bothering me for quite some
time.
In my perchlorate cells, both platinum and lead dioxide, I reported here the distinct odor of ozone (O3) being generated at the anode, and thought
perhaps that it might have been part of the reaction mechanism. It's not. It CAN and does form, but only with the incorrect setup and operation of a
cell.
Quote, from the excellent paper...
| Quote: |
Only oxygen and perchlorate are formed at the anode during electrolysis under the conditions used in this investigation [5]... The formation of ozone
can only take place under extreme electrolysis conditions like high current density and low chlorate concentration.
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Thus, high (excess) current densities, and/or low chlorate concentration, can result in O3 generation. Since I noticed ozone immediately upon power
up, I can only surmise that my current density was too high.
This can possibly be a tool... if the distinct odor of ozone is emanating from the vent port, dial the current back a bit.
The paper is a good one. I am going to spend a bit of time and try to absorb some of the theory.
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dann2
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Hello Folks,
@ tomasbrod
My advice regarding Lead Dioxide anodes is to STAY CLEAR of graphite as a substrate. You are going to need a perfectly formed coating of Lead Dioxide
and a fairly thick coat. You will not achieve this perfect coating in the set up that you have no matter how hard you try.
If you cannot get DSA try to coat some Titanium with Tin Oxide and start from there. If you cannot obtain Ti then start with a massive anode with
fiber reinforcing in it (grow it on Iron or a flat piece of Graphite.
The Graphite substrate is going to let you down, waste your time and your chemicals.
The text you are referring to Swede sounds alot like stuff I wrote. I wonder did the Iraq guy do all those experiments with a graphite substrate
Anode? It would take months and months. He certainly did not do it with one anode IMO.
Anyhow in the stuff that you copied and pasted he is actually claiming that :
"This type of anode [DSA] is finding increased use in industrial cells because of its comparatively low cost when co mpared to platinum and its
resistance to corrosion." [for perchlorate production].
This is nonsense. It is not and will not (in any sensible fashion) make Perk.
He also states that Magnetite has been used in industry for Perchlorate production which is more nonsense.
None of the references he gives in relation to DSA and Magnetite state that they can be used for Perchlorate production. He is mixing up Chlorate and
Perchlorte production.
(The myths continue)
Perhaps MMO made from Platinum Oxide (as suggested by JP Smith) will make Perchlorate. I don't know myself. I have never seen the stuff or don't know
if it is made commercially.
MMO made from Platinum Oxide should make Perchlorate because its Platinum Oxide that actually makes Perchlorate when using a Pt anode. (If you read an
article from Johnston Mattey). A very thin layer of Pt oxide forms on the Anode.
At the end of the day you are back to a Pt anode.
Dann2
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hyfalcon
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I don't know if anyone is still interested in this topic or not but I just found an interesting patent.
Attachment: insoluble anode of porous lead dioxide for electrosynthesis-preparation and characterization.pdf (869kB)
This file has been downloaded 1137 times
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tomasbrod
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| Quote: Originally posted by dann2 |
@ tomasbrod
You are going to need a perfectly formed coating of Lead Dioxide and a fairly thick coat. You will not achieve this perfect coating in the set up that
you have no matter how hard you try.
If you cannot get DSA try to coat some Titanium with Tin Oxide and start from there.
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Yes, you hav had true.
I let plating run for more than month on current as low as 10mA and got about 1.5mm coating. I mounted small phone vibrator (20x5x5mm) and set it on
timer to vibrate every half minute. Vibrations had not stoped bubbles forming and after three weeks vibrator felt from anode because strong acetic
acid vapours. I was lazy to set up NaCl electrolysis until now. Anode lasted two days on 0.3A and then cracked on two sides from top to bottom. Now i
have even more PbO2 powder and clean graphite rod. Now i have again some free time so I dissolved polistirene in turpentine. To paste I added MnO2
powder from batteries. I will put the paste in sharpe, let it dry and try to plate PbO2 ower it. If it fails I will try aluminium tin Zn and iron. My
method of preparation lead acetate is very fast and cheep on chemicals.
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Vikascoder
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There are lots of questions arising in my mind about Pb02 anodes
1 can battery anodes that is lead coated with lead dioxide be used directly in chlorate or perchlorate cell if no then why it can't be used
2 what is the best way of coating titanium with Pb02 so that it works for maximum time
Girls break promises like a small child breaks pencil tips so don't trust girl bcoz no girl=no tension
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IrC
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http://www.freepatentsonline.com/6248221.html
Since lead sheet is really easy to roll into cylinders this patent might be something to consider, as far as the cell geometry is concerned.
Attachment: US6248221.pdf (264kB)
This file has been downloaded 796 times
"Science is the belief in the ignorance of the experts" Richard Feynman
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