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garage chemist
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I found a supplier for RuCl3, it costs 159€ per gram which is ridiculous. Also, 5g would be the minimum amount to buy.
I'll look for Ru- free alternatives. I probably will make my own recipe using Pd, of which I already have some.
I know that MMO/DSA anodes dont make perchlorates.
Platinum is the optimal anode for chlorate ---> perchlorate, I have much experience with this (essentially zero platinum erosion when the chlorate
is pure and dichromate is used according to my experiments).
What is needed is a good non-eroding anode for chloride ----> chlorate.
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dann2
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| Quote: | Originally posted by garage chemist
I found a supplier for RuCl3, it costs 159€ per gram which is ridiculous. Also, 5g would be the minimum amount to buy.
I'll look for Ru- free alternatives. I probably will make my own recipe using Pd, of which I already have some.
I know that MMO/DSA anodes dont make perchlorates.
Platinum is the optimal anode for chlorate ---> perchlorate, I have much experience with this (essentially zero platinum erosion when the chlorate
is pure and dichromate is used according to my experiments).
What is needed is a good non-eroding anode for chloride ----> chlorate. |
Hello,
Have you ever tested your Perchlorate cell when for the presence of Chloride using Silver Nitrate. It would be interesting to see if any Chloride
shows up that is visually detectable using the Ag Nitrate.
According to Schumacher, The Perchlorates (book) some Chloride is produced in a Perchlorate cell from dissociation of Perchlorate (or is it reduction
at the cathode, I cannot remember).
If, say, all or most Perchlorate cells run with one or two percent Chloride in them due to the above there is little point in trying to recrystallize
Chlorate so that you get to the 100.000% Chlorate, 0.000% Chloride point.
Perhaps the amounts of Chloride generated in a Perchlorate cell are tiny when you use Chromate to stop reduction at the Cathode.
Regarding MMO for perchlorate I have run an mmo cell with Chlorate only (there was a few % Chloride in it too) for about three weeks, one amp into a
half liter cell. Current density about 130mA per cm squared. No Perchlorate formed.
In fact I was convinced the Chloride level increased somewhat at the start of the cell run. Ag Nitrate as a visual test was used for the Chloride.
NaF was used in cell. The MMO was an anti corrosion wire anode.
Ir + Ta Oxides on Ti rod AFAIK.
According to a patent I have read Lithium seems to form into the Perchlorate very easily (easier than the other more usual metals). Perhaps it may be
possible to get Li Perchlorate to form at MMO.
I guess there is only one way to find out.
Cheers,
DANN2
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jpsmith123
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It's confusing to me since a few people have in the past claimed to make perchlorate with pool chlorinator anodes.
I suppose it probably depends on the exact MMO composition and process details. From what I've read, PdO would be better than RuO2, for example.
Right now I'm having a discussion with someone on rec.pyrotechnics about it. He's already made chlorate, and is now attempting to make perchlorate. I
don't think he knows the composition of his MMO coating, however.
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Rosco Bodine
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Some interesting patents
These few should probably be added to the collection
of patents having possible usefulness with regards to perchlorate anodes .
US4422917 Describes a substoichiometric titanium dioxide
which is formed by high firing the normal stoichiometric material in the presence of a reducing material admixed
with the clay , or firing in a reducing atmosphere . The resulting vitrified ceramic has extreme corrosion resistance
and electrical conductivity similar to graphite , and high
oxygen and hydrogen overvoltages which allow for its use as either anode or cathode or both .
US5126218 gives more information on the ceramic material
which is / was commercially produced and called Ebonex
by Lambertville ? More information on this I have not searched , but here is a page link for a manufacturer
http://www.atraverda.com/Ebonex_tech.htm
There is a hundred page book on the material by the inventor available from RSC publications
http://www.rsc.org/publishing/ebooks/2001/9780854049844.asp
US2994649 Describes a method for plating beta PbO2 on a stainless steel substrate , maintaining current efficiency by
a concurrent addition of hydrogen peroxide to the nitrate plating bath . This might have usefulness for the production
of massive PbO2 anodes on a cheaper more readily available substrate from which the finished part may be stripped .
US3033908 Appears to be the original patent concerning
alpha PbO2 , and describes a bath which is a combination of lead acetate with sodium nitrate , operated at room temperature and a slightly acid pH .
This patent is of particular interest to me anyway , as it produces the alpha
PbO2 under conditions which are close enough to those for
the nitrate bath used for deposition of the beta PbO2 , that
it seems possible to devise a plating mixture which could concurrently precipitate both alpha and beta PbO2 in a blended structure which would be
inherently stable by
virtue of being internally stress relieved at a microstructural level . Also interesting is that this bath for alpha PbO2 produces a deposit which is
not so strongly adherent to the substrate as is the deposit from the alkaline tartarate bath
of US4064035 , and this could be an advantage in the easier
separation of a massive anode from a substrate , where the
alpha PbO2 is used as a priming layer . Also , it would seem
that because this alpha PbO2 bath is acidic , that it may allow for use of a graphite substrate .
[Edited on 24-6-2007 by Rosco Bodine]
Attachment: US2994649 _LEAD_DIOXIDE on stainless steel substrate.pdf (112kB)
This file has been downloaded 948 times
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garage chemist
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My Perchlorate cell does not produce any chloride, I've tested it with AgNO3 before and after the run.
I use dichromate and commercial 99% NaClO3.
Once I ran it without dichromate, and then it definately produced some chloride. The platinum anode was also visibly attacked, which did never happen
before when I used dichromate.
So it is probably cathodic reduction which forms chloride, and this is prevented by dichromate addition.
Can dichromate be used with MMO anodes in a chlorate cell? I'm unsure about that.
Does anyone have patents concerning manufacture of chlorine- resistant MMO anodes using PdO/PdO2 and TiO2 as the conducting oxide? If I cant find any,
I'll use one of the Ru based recipes (butanol, butyl titanate) and substitute RuCl3 by H2PdCl4.
Who knows what butyl titanate is supposed to be? Can it be made from TiCl4 and butanol?
[Edited on 31-5-2007 by garage chemist]
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Rosco Bodine
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Hmmm...aluminum is a listed "valve metal" !
Maybe this has been mentioned before , I don't think so .
If the combined tin and antimony oxides which are baked onto a "valve metal" as a semiconducting "anodization" , and upon which can be plated PbO2
......then aluminum
could certainly be useful as a cheap and easily removable
substrate for a massive PbO2 anode .
The idea would be to first produce the aluminum sheet with
the combined oxides and place it in a plexiglass baffle ,
a sort of picture frame which would blank off the backside
and edges from the plating on of the PbO2 . So the PbO2
could be built up into a 3/8" - 1/2" thick layer on the front side only . The completed anode could be separated from
the substrate by simply scratching through the oxides layer
on the unplated backside , using a rotary stone or file to
expose naked aluminum . Paint on some HgCl2 in dilute HCl
and immerse the whole assembly in dilute HCl or any other
dilute acid and the aluminum substrate would be etched away completely , leaving the massive PbO2 in one piece ,
no chance of breakage from otherwise having to pry it away
from a metal substrate . And no expensive titanium required .
Along the same line of thinking , a massive PbO2 anode
could similarly be plated onto one side only of a thin graphite
sheet , and then not even attempted to be pryed from
the thin graphite substrate .....but put into use in the cell
where the corrosive action of the cell itself erodes away the
graphite substrate , leaving the massive PbO2 anode to
continue working just fine ( hopefully ) after having been
relieved of its graphite .
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alancj
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Does strong alkali attack PbO2? Considering that some plating baths are alkaline, I'm thinking it should be inert to it. If it is, then a solution of
sodium hydroxide would easily dissolve the aluminum right off.
-Alan
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Rosco Bodine
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IIRC there is better resistance of PbO2 to acid than to alkali , and the etching away of amalgamated aluminum
is a whole lot more rapid in dilute HCl than in alkali .
Another possibility for using aluminum as a substrate
is to plate onto it 20 microns or so of nickel or cobalt ,
and then plate on the lead dioxide . Of course this
nickel plated aluminum would never hold up in a chlorate cell , but it would hold up in the lead dioxide plating process . And then similarly , by
scratching through the
thin plating , and loosing upon the aluminum the HgCl2 ,
the same disappearing of the aluminum would occur .
But really , the more I think about the graphite idea ,
the more it seems like the simplest idea to just let the
cell itself eat away the graphite . The substrate of course
is expendable for either of these approaches ....it is a one
use substrate , which is the only down side that I can see about this idea .
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dann2
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Pt or MMO Pool Chlorinator Anode
| Quote: | Originally posted by jpsmith123
It's confusing to me since a few people have in the past claimed to make perchlorate with pool chlorinator anodes.
I suppose it probably depends on the exact MMO composition and process details. From what I've read, PdO would be better than RuO2, for example.
Right now I'm having a discussion with someone on rec.pyrotechnics about it. He's already made chlorate, and is now attempting to make perchlorate. I
don't think he knows the composition of his MMO coating, however. |
I think some of the Pool chlorination anodes are Pt based. They have a coating of Pt on them (not the shiney variety but the black variety). They are
described as bipolar. Think that means you can put an ac to them. It also means you can reverse the DC (if using dc) to clean them.
There was a guy here using a 'sachlor' anode to make Perchlorate. A fellow contributor said this anode was a Pt based anode. The user thought/said it
was MMO.
Thread can be got from here:
http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...
EDIT:
Sorry JP it was yourself that uploaded the pool anode image
Cheers,
Dann2
[Edited on 31-5-2007 by dann2]
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dann2
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| Quote: | Originally posted by Rosco Bodine
Maybe this has been mentioned before , I don't think so .
Along the same line of thinking , a massive PbO2 anode
could similarly be plated onto one side only of a thin graphite
sheet , and then not even attempted to be pryed from
the thin graphite substrate .....but put into use in the cell
where the corrosive action of the cell itself erodes away the
graphite substrate , leaving the massive PbO2 anode to
continue working just fine ( hopefully ) after having been
relieved of its graphite . |
The whole problem (as I see it) with the massive anodes is that you are going to need very good plating conditions. Well controlled temp.,
concentrations, etc. It is difficult to get one big piece of Lead Dioxide to stay together. It is also VERY fragile. Let it fall and it's goodnight
anode.
The substrate (if we can get one) is essential reinforcing.
Dann2
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hashashan
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i have dropped my anode (very thick anode on fabric) several times from about 1.5 meters and it didnt crack. So this PbO2 is not so fragile as one
might think. As soon as it gets above 3mm thick its quite strong/
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jpsmith123
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Garage Chemist, several of Beer's patents have examples that use PdO (from PdCl2). I think the main reason PdO is not used commercially is because Ru
and Ir are significantly cheaper.
As far as I can tell, the processes are basically the same regardless of which PGM oxide is used; IOW, the PdO/TiO2 coating can be put on
electrolytically or by thermodecomposable salt solution.
I think I posted the "recipe" for electrodeposition of a RuO2/TiO2 coating somewhere here before. I can post it again if you can't find it.
BTW there are a few Japanese patents that exclusively use PdO. Supposedly it has a very high oxygen evolution overpotential, thus I think it would be
a good candidate to make perchlorate.
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garage chemist
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I just looked for Beer's patents, and found one where Pd is used:
US3711385
But no TiO2 is used here, so the electrode obtained in that way most likely wont be as resistant as one with TiO2 and PGM oxide.
I keep looking for a patent which describes a TiO2/PdO anode.
Pd seems to be much cheaper than Ru, but the prices of all those metals have changed very much over the years, so what once was cheap can today be
very expensive. Pd is currently much cheaper than Pt.
EDIT: Another one which uses Pd, but again without TiO2: US4052271
Maybe I'll try one of those when I get my titanium, and see how well they hold up. Maybe it is not necessary to purchase TiCl4 in order to make a
functional DSA coating.
If it doesnt hold up, Ru and TiCl4 will probably have to be purchased, with Ru from a supplier who has decent prices.
[Edited on 31-5-2007 by garage chemist]
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jpsmith123
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There used to be someone selling RuCl3 on ebay, although I don't see it there anymore. I think PdCl2 is easier to find and cheaper because Pd has more
industrial/commercial uses.
Here's 5 grams of RuCl3 for sale for $72.60:
https://new.fishersci.com/wps/portal/PRODUCTDETAIL?LBCID=856...
With regard to a PdO/TiO2 coating, I will have to look for it. In the mean time, in Beer's patent# 3632498, on page 4, there is a table where he
qualitatively compares the various "coprecipitated oxides", and Pd/Ti is among the contestants.
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Rosco Bodine
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| Quote: | Originally posted by dann2
The whole problem (as I see it) with the massive anodes is that you are going to need very good plating conditions. Well controlled temp.,
concentrations, etc. It is difficult to get one big piece of Lead Dioxide to stay together. It is also VERY fragile. Let it fall and it's goodnight
anode.
The substrate (if we can get one) is essential reinforcing.
Dann2 |
I think you folks are so in love with the idea of titanium substrates and elegant semiconductor coatings that you can't see the forest for the trees .
There are several different sources which indicate that the massive PbO2
anode is technically superior and much easier to make .
And in terms of technical difficulty and need for exotic materials and labor intensive high temperature lamination of doped oxides onto titanium ,
......for all that work on a substrate , it is still the PbO2 which is the working surface ,
and the only real advantage gained it would seem is not
needing to silver plate for the connection when a conductive
permanent internal substrate is being used . Given the costs
of titanium and the other materials and labor ....I just don't see how the doped titanium substrate is superior except in terms of bragging rights for
having the product of exotic materials and methods and a whole lot of work , which may
not even last as long as a massive PbO2 anode more easily and cheaply made .
Aside from the previously mentioned possiblility of coplating
alpha and beta PbO2 from a mixed bath , it may also be possible to add the barium dioxide component as a third component , all being blended and
layered either as distinct
plys simply by stepwise variation of the plating current , or
as a continuous composite laid down by a varied intensity
waveform of direct current as may come from rectified AC .
The possibilities of using common and economical substrate materials which are temporary substrates only used in the
anode deposition process and then stripped from the massive anode which serves as the working part are obviously superior economically and technically
simpler ....
if the service life of the end result is acceptable .
Bottom line is that no matter how exotic the substrate ,
even if pure platinum , the working layer of PbO2 will
separate eventually if it fractures exposing the substrate ,
whether the substrate corrodes away or not ....the anode
will fail some time after fracturing , even if it takes a considerable time after the working coating fractures .
This will hold true for the oxide treated titanium substrate ,
as the poor mans platinum substitute will fare no better
than the real thing . It will most definitely eventually fail in a similar way , worse than would a platinum substrate , though to a lesser extent
even the platinum will erode .
Therefore it would seem that the very best substrate is no substrate at all . Because any substrate which isn't truly inert in the cell will
eventually compromise the anode .
Attached is one patent for the massive PbO2 electrode ,
although there are many variations on the theme described in other patents . The drawings are not very good really , and they are showing a scheme
where both sides of the substrate are used for making a pair of massive anodes simultaneously . This is in contrast to my idea of blocking off the
backside and forming one massive anode only on the front surface of a substrate . This one side plating of a substrate , including a graphite
substrate , has been described in other patents . What I am suggesting has in some forms been done already . But I don't know of any
references where various refinements have been combined
to try to optimize the massive PbO2 design .
Attachment: US2846378 Massive PbO2 Anode method.pdf (388kB)
This file has been downloaded 1363 times
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12AX7
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How about this: take a sheet of, say, copper, apply duct tape to the narrow sides, and plate PbO2 over it. Now, peel off the tape and copper (or
dissolve it in nitric). Voila, two massive anodes, pure PbO2!
Nevermind that it'll take ages to plate, but still...
Tim
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dann2
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| Quote: | Originally posted by 12AX7
How about this: take a sheet of, say, copper, apply duct tape to the narrow sides, and plate PbO2 over it. Now, peel off the tape and copper (or
dissolve it in nitric). Voila, two massive anodes, pure PbO2!
Nevermind that it'll take ages to plate, but still...
Tim |
I hate to be a party pooper (read: I love being a party pooper:-)) but the massive Lead Dioxide anode is not an easy thing to achive. Have you ever
heard of anyone, having made a substrate anode, had it fall apart, being left behind with a quantity of usable massive anodes at the bottom of the
Chlorate tank.
It is my opinin that when you have plated on your perfect (and it had better be perfect) coating of Lead Dioxide on your removable substrate, that you
will be very lucky to have a usable anode left after you remove said substarte. Perhaps I have gone Ti mad.
A lot of the literature I have read (not patents) that have mentioned massive anode have always said that they were problamatic or that the yield was
low. ie. expect a large failure rate when making them.
The Lead Dioxide that most amateurs will plate (at least like myself) will not be of A1 standard. When substrate is removed (intentionally as when
making a massive anode or unintentionally as when a substrate anode gives up the ghost) you will be left with only small pieces of Lead Dioxide.
Perhaps I am too pessimestic.
The cloth substrate anode is really a massive anode with some reinforcing in it. The cloth (or whatever) hopefully holding the whole lot together. I
would suggest of anyone is making massive anode would be to try and incorporate some sore of cloth/mesh material into the anode to help hold it
together.
I once had a massive anode. It was a piece that came off the side of a ceramic substrate anode and was about 1.5cm
by 7cm by 3mm thick. Not a very big anode by any standards.
It was the only piece of Lead Dioxide that I ever got that was usable out of all the anodes that fell appart.
Most of the patents make anode making sound very very straight forward always adding some new device/process/chemical that allegedly transforms the
whole process.
I noticed that the patent that Rosco put up here yesterday? (thank you) used a 300 gallon!!!!!! tank of Lead Nitrate.
They did not mention what size the anode was but a tank
that size (unless the anode was being lifted in and out of the tank with a crane) would give a very stable pH, Ion concentration and temperature
during the course of the plating process.
Few are willing to invest in a two or three gallon tank per smaller anode.
Dann2
(wasp chewing)
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dann2
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| Quote: | Originally posted by hashashan
i have dropped my anode (very thick anode on fabric) several times from about 1.5 meters and it didnt crack. So this PbO2 is not so fragile as one
might think. As soon as it gets above 3mm thick its quite strong/ |
Hello Hashashan,
Did you do this on purpose to test the ande or was it an accident?. If you did it as a test you are a much braver man than myself (and most others too
I guess  )
Dann2
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Rosco Bodine
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Industry patents have in general proven to be sources of good information for me anyway , although there are a few
exceptions ...some of which can be debunked with a little effort . Several of the PbO2 deposition method patents test the particular process for its
value in producing a massive anode , since a quality strain relieved thick layer is stable as a massive anode , whereas a stressed deposit indeed
will crack and crumble . It is sort of a litmus test for the stability of the plating which will then be also stable in much thinner platings on
anodes which do have a substrate .....if that is the interest instead .
I don't have a problem with setting up the equipment necessary to test some of these ideas , as I already have
most of the needed materials and equipment on hand for
other uses . It is simply a matter of finding time , clearing my bench , and setting it up and running the process . I can pretty closely duplicate
the controlled conditions described by the patents .
If you look at the example 3 in patent US4064035 ,
there is an example of one side of a graphite substrate being
plated with a thick layer of PbO2 . But it seems like they are using an overly thick graphite which must then be separated
with some difficulty . This is one of those points where it appears they simply used the material which they had on hand , which was not ideal
....but the focus of interest was the massive anode produced succesfully . IMO a thinner substrate plate could have functioned just as well .
Anyway , as for the complexity of the anode production setup required , unless you are doing some really thin buildups of PbO2 , then you are going to
need the same equipment for making a massive anode , it simply has to run for longer time to build the added thickness . I see no difference there in
the technical requirement except for the longer time for the plating run , and of course more lead salts for replenishing the bath .
@12AX7
Copper can be used as a temporary substrate for PbO2 as can aluminum , if it is first plated with nickel . Of course since copper would be more
difficult to etch away , as compared with amalgamated aluminum , copper would seem to offer no advantage over say stainless steel which could be used
directly without plating , in a bath containing hydrogen peroxide . Physically prying off the deposited anode would be required for the stainless
steel substrate , and that is likely to be the case also for the copper . It would seem that
a concentrated enough nitric acid for etching away the copper would likely also attack the PbO2 . So copper would
seem not to be a good candidate as a substrate due to these complications , even with the use of super duper duct tape around the edges , and several
hopeful alchemists chants and amulet waving ....it just doesn't seem likely
Aluminum however , with nickel plating is another matter .
Attached is a patent US2492206 which describes construction
of a special type of battery capable of producing high current even when operated in extremely low temperatures where conventional batteries
deactivate . The patent , although
it relates to production of a primary cell , makes use of a lead dioxide anode , and some details of its preparation are pertinent to PbO2 anodes in a
more general sense , including the production of perchlorate cell anodes .
For example the same plating bath could be used for our purposes , and a drawing shows the setup , which includes
a small recirculation pump and filtration arrangement perfectly applicable to our needs . An aquarium power filter
would seem perfect to fit the function of maintaining the pH
and Pb content of the plating bath . The patent also mentions the usefulness of basic lead salts for buffering the
pH , which is something I have mentioned also would be preferable to the use of lead carbonate or oxide .
@dann2
The important detail to learn from the patent US2994649 which described the usefulness of hydrogen peroxide for
control of nitrite levels which destroy the efficiency and quality of a plating bath , is not that it only works in a 300 gallon government facility
plating tank ....but that it likely solves the same problem the same way in a laboratory scale plating bath . The problem of increasing levels of
nitrites has a simple solution , and if that solution improves the performance of a bath enough that plating onto a stainless steel substrate becomes
efficient , as well as improving the plating onto nickel and even platinum , then it is a worthwhile additive which very probably results also in a
better quality of PbO2 deposit . Increased cell efficiency means less waste heat from IR loss and side reactions which
should translate to a cleaner purer and denser PbO2 deposit which is laid down at a faster rate . These are good things , ......not problems .
BTW , on your website there is an interesting
article , JES Vol.104, No. 7 (July 1957) page 448
Electrolytic Production of Bromates , which describes
the deposition of massive PbO2 anode material on *iron*
substrate from a *neutral* pH lead nitrate bath . It would hardly get any simpler than that , if a piece of low carbon soft steel would work as well
. I am thinking cold rolled bar stock could do the trick as a substrate . or possibly even a soft cast iron , or mild steel .
http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...
[Edited on 1-6-2007 by Rosco Bodine]
Attachment: US2492206 Nickel Plated Aluminum PbO2 Electrode.pdf (213kB)
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hashashan
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| Quote: | Originally posted by dann2
| Quote: | Originally posted by hashashan
i have dropped my anode (very thick anode on fabric) several times from about 1.5 meters and it didnt crack. So this PbO2 is not so fragile as one
might think. As soon as it gets above 3mm thick its quite strong/ |
Hello Hashashan,
Did you do this on purpose to test the ande or was it an accident?. If you did it as a test you are a much braver man than myself (and most others too
I guess )
It was an accident ... however it did occur several times.
And i see you are offering to plate PbO2 on metals and then ermove the metals .. I CANT BELIEVE IT .... look about 3 or 4 pages back .. i offered it
and you all told me that its a waste of time.
Dann2 |
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garage chemist
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OK, found curent price of ruthenium: about 850$ per ounce.
Thats only slightly cheaper than platinum, while Palladium is very much cheaper than platinum. So you see, recipes using Pd are to be looked for.
I also found a source for Ru powder close to market price (but thats still about twice the price of palladium).
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Eclectic
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Industrial Bullion Prices
I see $540/troy oz. It was $67 or so a few years ago when Pd was $180. Ir was $70!
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dann2
International Hazard
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| Quote: | Originally posted by Rosco Bodine
Industry patents have in general proven to be sources of good information for me anyway , although there are a few
exceptions ...some of which can be debunked with a little effort .
BTW , on your website there is an interesting
article , JES Vol.104, No. 7 (July 1957) page 448
Electrolytic Production of Bromates , which describes
the deposition of massive PbO2 anode material on *iron*
substrate from a *neutral* pH lead nitrate bath . It would hardly get any simpler than that , if a piece of low carbon soft steel would work as well
. I am thinking cold rolled bar stock could do the trick as a substrate . or possibly even a soft cast iron , or mild steel .
http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...
[Edited on 1-6-2007 by Rosco Bodine] |
This set up uses 5 tanks, two stirrers, a pump and constant pH monitoring. Not impossible but not too simple either.
Most people only want to bother with one tank. Perhaps thats the problem.
If you are going to plate any substrate that is attackable by nitric acid from a nitrate bath you must plate with a neutral or near neutral bath. This
will require two tanks. It is difficult to keep pH close to neutral as it will drop rapidly as plating commences due to formation of nitric acid.
You cannot do it in a one tank set up IMHO.
Dann2
[Edited on 1-6-2007 by dann2]
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garage chemist
chemical wizard
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Hmm, then our sources are contradicting- dont know my source though, it was some website.
Anyway, I cant get it for market price at such small amounts. Its damn hard to find a supplier for this, I called up Degussa and Chemetall and none
had Ruthenium or Ru compounds among their products.
My supplier wants 25€ a gram, which is acceptable.
Palladium is still cheaper, and I already have several grams of it.
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Rosco Bodine
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| Quote: | Originally posted by dann2
And i see you are offering to plate PbO2 on metals and then ermove the metals .. I CANT BELIEVE IT .... look about 3 or 4 pages back .. i offered it
and you all told me that its a waste of time.
Dann2 |
Just now also replying belatedly to a message from four pages back .....WTF happened to dann2's current post ? Don't be shy and then delete  When you have a mouthful of lead salts and iron filings ....spit it out !
| Quote: | Originally posted by dann2
If you are going to get into the business of growing massive Lead Dioxide anode (like growing an anode by starting with 2 cm of Pt.) you will need a
well contolled set up. Good pH control, fearly steady Lead Ion concentration, steady temp. etc etc. |
A well controlled setup is really what is needed in any case ,
unless you have a relatively huge volume plating bath for
the size of the anode being made , so that its composition changes but very little from the decreasing lead ion and changing pH .
| Quote: |
Lead Dioxide can be deposited on Pt. It has been done many times when Ti was plated with Lead Dioxide. A thin coating of Pt was deposited first to
protect the Ti from the Lead Dioxide.
I was flicking through a library book today and read that Lead Dioxide was known as the 'Poor man's Platinum'. HUH.
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Yeah PbO2 was probably used as a protective oxide for preventing the erosion of platinum anodes ....cheaper to have PbO2 eroding away and replace it
as needed by replating the platinum with a fresh coat , than to have
platinum steadily eroding as the unavoidable cost of production . That could become costly for huge production facilities making tons of material .
| Quote: |
You can grow massive anodeS on Iron, Nickle and other wires. It has been done in the journals. The maker started with a close to neutral Lead Nitrate
bath and kept plating solution treated with Lead Carbonate etc to neutralize the nitric acid as it was produced to stop it from attacking the Iron,
Nickle etc. Well controlled set up. |
I can see a problem with growing a coaxial deposit having a wire as its core . The wire limits the amount of current which
can be delivered , while maintaining the same current density
for plating upon an exponentially expanding outer surface would require ramping the voltage to overcome the IR loss in the wire . It would be
entirely better from an electrical supply side perspective to be depositing the plating upon a planar substrate whose surface area of accumulating
deposit is relatively constant .
But the truly interesting aspect of the massive PbO2 anode
capability is that it may be deposited from a neutral pH bath
of lead nitrate , ( and perhaps from other neutral salts ) upon
an ordinary *iron* substrate . It would seem that exploiting
this cheap *iron* material as a temporary substrate , would make available a lot of money which might otherwise be spent upon exotic and expensive
substrates , which could be much better spent on the apparatus for closely controlling the quality of the plating bath itself to produce massive
anodes which have a service life of longer than one year while being made of only cheap material .
[Edited on 1-6-2007 by Rosco Bodine]
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