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dann2
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Tin Oxide + Antimony Oxide Anode
Hello,
During a discussion regarding (Per)Chlroate Anode making someone here asked about a patent (and give a number) which described making a Ti substrate
anode which involved Tin and Antimony Oxides only. No Lead Dioxide or anything else.
Can anyone here tell me where the post is, I cannot find it for the life of me.
Hope description is accurate.
TIA,
Dann2
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12AX7
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For reference:
http://www.sciencemadness.org/talk/viewthread.php?tid=2465&a...
"...a semiconducting coat of Sb doped SnO2..."
"...Then a thin (about 0.1mm) layer of alpha PbO2..."
"...The final coat of beta PbO2 was then plated..."
The SnO2 sounds like a primer as it were, perhaps to improve conductivity (Ti is almost impossible to plate as it anodizes readily).
I wonder if the more popular indium tin oxide would work even better.
Tim
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dann2
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Thanks for reply,
The thread was about two months ago. The anode the guy mentioned did not involve any lead dioxide, only (I think) tin and Antimony oxide. Perhaps I am
mistaken.
Cheers,
Dann2
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dann2
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Hello,
I found the patent (or one similar). It used a doped Tin oxide on its own an
an anode for brine electrolysis.
Part below.
_________________________________________________________
US Patent No. 3,627,669
Example 1 only. The electrode was used without any coating over the Doped Tin.
EXAMPLE 1
A composition suitable for coating on to an electrode support was prepared by boiling under a reflux condenser for 12 hours a mixture of 15 g. of
stannic chloride, 0.4 g. of water and 55 g. of n-amyl alcohol and then stirring into 5.8 g. of the resultant mixture 0.125 g. of antimony trichloride.
Twelve coats of this composition were painted on to a strip of titanium which had been immersed overnight in hot oxalic acid solution to etch the
surface, then washed and dried. Each coating was dried in an oven at 200.degree. C. before the next coat was applied and after each third coat the
structure was heated in air in a furnace at 450.degree. C. to convert the coating substantially to the oxides of antimony and tin. The total weight of
the finished coating was 11.0 g./m squared of the titanium surface. The theoretical composition of the finished coating was SnO2 90 percent, oxides of
antimony (calculated as Sb2O3) 10 percent by weight.
The coated titanium was operated successfully as an anode in chlorinated brine containing 21.5 percent w/w NaCl at pH 3 and 65.degree. C. with a
current density of 8 kA/m squared. The chlorine overpotential was initially 470 mv. and had risen to 480 mv. after 5 days.
________________________________________________________-
Dann2
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jpsmith123
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Here's another patent I just found.
In this patent, a layer of tin and antimony oxides is used as an intermediate layer between the titanium substrate and an outer coating of MnO2.
But there is also an example where the MnO2 is put on directly over the titanium without using any SnO2.
In some examples, the MnO2 is electroplated on from an aqueous MnSO4 solution (and then baked) and in other examples, it is formed by thermal
decomposition of a manganese nitrate solution.
Since a 5 lb bag of manganese sulfate can be bought for under $10 from a garden store, and if the MnO2 can be easily electrodeposited onto titanium or
graphite (as the literature implies) and if it can be easily converted to the beta form at kitchen stove temperatures, and being that it is relatively
non-toxic and environmentally friendly...then it may be the ideal material for an anode for small scale perchlorate production.
It may be a little less efficient than PbO2 or platinum, but if the above advantages can be realized, that's a small price to pay, IMO.
And even if it only lasts a few hundred hours, so what? You can just make another one.
Attachment: 4028215.pdf (702kB)
This file has been downloaded 847 times
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dann2
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Hello,
Sounds like a good find.
Manganese sulphate in the Garden store? is use as a trace metal supply for plants? or did you mean ceramic store.
Did not read the patent yet (downloading slow connection), but perhaps the anode with no Sn02 undercoat was/is a massive anode as such. The electrical
connection NOT being made to the Ti but to the MnO2 directly. The Ti just being used a physical thing to hold the MnO2.
Seen a Lead Dioxide anode patent done that way.
Good find.
Cheers
Dann2
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jpsmith123
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Here's a 5 lb. bag of manganese sulfate for sale on ebay. I guess you could call it "fertilizer".
http://cgi.ebay.com/Manganese-Sulfate-for-Palms-Trees-Shrubs...
BTW "Example 8" of the patent is the case without the intermediate layer. It seems the electrical connection was made to the titanium as they mention
a somewhat higher voltage on the electrode compared to those with the intermediate layer.
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hashashan
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but what will you do whith an anode that cant go from chloride to perchlorate directly.
the removal of chloride from the chlorate is quite a mess
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alancj
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Well, there ARE other uses for good anodes... one could use it to produce a myriad of other products from electrolysis. Of course they're all boring
except for the (per)chlorates 
I have MnO2, any ideas on turning that into the sulfate?
-Alan
edit: wait, I think there is a thread on that already...
[Edited on 28-5-2007 by alancj]
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12AX7
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| Quote: | Originally posted by hashashan
but what will you do whith an anode that cant go from chloride to perchlorate directly.
the removal of chloride from the chlorate is quite a mess |
How do you figure? I find it quite simple. I don't have silver nitrate on hand, but I do have lead acetate on hand and I can quite easily wash
potassium chlorate to that extent (less than 0.1% Cl, say).
Tim
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dann2
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| Quote: | Originally posted by alancj
Well, there ARE other uses for good anodes... one could use it to produce a myriad of other products from electrolysis. Of course they're all boring
except for the (per)chlorates
[Edited on 28-5-2007 by alancj] |
Hello,
The Perchlorates seem to be where everyone is trying to get to.
All anode materials that can make Perchlorate will go from Chloride to Perchlorate without stopping as far as the chemistry is concerned (AFAIK).
It is the wear excessive wear rate that makes it not a great way to go. Perhaps I am too obsessed with wear rates but even graphite costs money and
then there is the horrible mess........
There are three types of MnO2, Alpha, Beta and Gamma.
Alpha you do not want, Beta is best, Gamma is OK. (AFAIK)
Beta is what you get with thermal decomposition methods.
Gamma with electrodeposition methods.
There are other oxides you do not want which you get if you
heat too much.
Mn02 does not alloy into Ti oxide (like the way Ru Oxide does).
I pulled the following from a book.
From Electrodes of Conductive Metallic Oxides (Book)
In the case of Mn(NO3)2 the decomposition takes place at relatively low temperatures, practically
already at 100C. The choice of the pyrolyzing temperature is very critical in this case in that at higher
temperatures (above 400C) MnO2 decomposes to Mn2O3. The closeness of the two temperature ranges is such that
mixed oxides or MnO2 with a surface layer of Mn2O3 are often obtained. Such a surface film strongly decreases
the conductivity of the entire layer.
The pyrolysis of Mn(NO3)2 gives the Beta form of MnO2 (but below
150C other varieties of MnO2 may be obtained), whereas the electrochemical deposition and chemical
methods give rise to Gamma MnO2 (at room temperature Alpha MnO2 may be obtained). The relationship
between Beta and Gamma is one of stoichiometry and lattice order. The transition from one form to
the other occures by simply heating. The Gamma form loses water progressively and becomes increasingly
stoichoimetric until the Beta form developes. Above 400C decomposition to Mn2O3 takes place and at
higher temperatures Mn3O4 is formed. Beta MnO2 losses water at 110C which is however not bound to
the lattice. As a matter of fact, electrodes are sometimes prepared with a pyrolythic layer covered
by electrolythic MnO2.
MnO2 has also been prepared from the Carbonate by pyrolysis.
Beta MnO2 has higher conductivity than Gamma MnO2
_______________________________________________________
Dann2
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alancj
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| Quote: | Originally posted by 12AX7
| Quote: | Originally posted by hashashan
but what will you do whith an anode that cant go from chloride to perchlorate directly.
the removal of chloride from the chlorate is quite a mess |
How do you figure? I find it quite simple. I don't have silver nitrate on hand, but I do have lead acetate on hand and I can quite easily wash
potassium chlorate to that extent (less than 0.1% Cl, say).
Tim |
I think what hashashan meant was that it is hard to separate out sodium chlorate from the chloride present in a chlorate cell in order to prepare it
for a perchlorate cell. This is an issue if your anode can't be used to go all the way from chloride to perchlorate non-stop. The potassium salt
can’t be used to make perchlorate since both are not very soluble.
-Alan
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hashashan
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Of course you can purify the chlorade from the chloride. I did it once, but it is a reall mess.
Either you recristalyze several times(if you have about 3 liters it can take you all day to do so) or you can go to potassium, recrystalize once and
then return to sodium using sodiumn sulfate (which is also not a very good method because you do have to wait quite a lot time before all the
potassium sulfate settles.
Anyway i call a perfect anode an anode that i can just stick into a bucket and go to a trip for 2 weeks, come back and get perch.
if you have to purify it somewhere in the middle its not very good, too mesy for me.
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jpsmith123
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Dann2, there are several MnO2 anode patents assigned to "Diamond Shamrock". They seem to be saying in all these that Mn(NO3)2 generally makes a better
MnO2 anode than any other precursor compound such as MnSO4.
According to them, this is true whether the coating is put on by electroplating or by way of painted-on thermodecomposable salt solution.
They also claim that anode quality is dependant on baking temperature and impurities.
As I see it, a significant part of this effect must be mediated by changes in crystal size and/or structure.
And if this is the case, then who knows, maybe a MnSO4 solution with the right additive might be just as good a precursor as Mn(NO3)2.
I'm attaching a paper which discusses making MnO2 by electrodeposition from MnSO4, using a TiSO4 dopant. (Although this particular paper was concerned
with making MnO2 for cathode material in an alkaline cell it is an interesting read).
(BTW I wonder if MnO2 anode subject matter shoud be under its own seperate heading?)
Attachment: Electrodeposition of Manganese Dioxide technical report.doc (102kB)
This file has been downloaded 1750 times
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dann2
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Hello,
@Roscoe
Do you have any Anode patents involving DTO that have a low Sb content in the DTO coating that do not substitute something else (Nobels) for the
Antimony.
You stated that they were posted to the board. I am unable to find any.
Dann2
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Rosco Bodine
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I'm trying to find it just for you 
Here's one but I'm not sure it is the one I had in mind so I will add to the list as I can .
US3917518
US3865703
US3793164
The noble metals were for doping the TiO2 more than the SnO2 . As they would use thicker layers of SnO2 the Sb was substituted because it was cheaper
, and did a fine job of
making the SnO2 conductive , even though it didn't do much for the TiO2 . As for the nobles being substituted for the
Sb , you have it backwards what they were doing .
You don't need to use more Sb to account for the lower
use of nobles . Because even at very low levels of Sb ,
a couple of percent to perhaps 5% , the job of making the SnO2 conductive is accomplished and then some , and the conductivity worsens from there with
increasing Sb , while the physical integrity of the layer suffers also .
[Edited on 18-12-2007 by Rosco Bodine]
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jpsmith123
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Just wondering, has anyone been able to use OTC 95/5 solder to make a suitable precursor for a pyrolytic DTO coating?
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Xenoid
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| Quote: | Originally posted by jpsmith123
Just wondering, has anyone been able to use OTC 95/5 solder to make a suitable precursor for a pyrolytic DTO coating? |
I thought that's what everyone was already using, there are plenty of references
http://www.sciencemadness.org/talk/viewthread.php?tid=8592&a...
better speak to Eclectic about it!
I gather Dann2 doesn't have access to 95/5 lead free solder, thats why he's working with the separate elements - AFAIK.....
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Rosco Bodine
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Sheesh it is beginning to look like a bismuth containing
solder alloy could be desirable as well ,
if indications this may be the case are confirmed .
It may take the Sb working together with the Bi ,
At this juncture though, both appear to possibly , probably , be needed together . Wish I could be more specific .
[Edited on 18-12-2007 by Rosco Bodine]
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dann2
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Hello,
| Quote: | Originally posted by jpsmith123
Just wondering, has anyone been able to use OTC 95/5 solder to make a suitable precursor for a pyrolytic DTO coating? |
I have failed in all attempts. Perhaps someone more skilled in the art, eh. But on a serious note SnCl2 (<strike>the Stannate</strike>
sorry Stannous Chloride!!!) has not been used in any patent that I have seen. I have been using ebay Tin and Sb metal at above 15% Sb. Also used
SnCl2:2H20 (solid out of a jar) + SbClx (Sb metal dissolved with HCl + H2O2).
Then there is the 'upping the oxidation state to Stannic (SnCl4) thing'. I was not able to make any headway with that either.
One problem I had was when you added the Sb Trichloride to the SnCl2 + H2O2 mix, it ppt'ed as Sb Oxide (or is it Hydrated Oxide).
If some of you guys could come up with a plan for to get solid SnCl4:5H2O from the SnCl2 + H2O2 then it may be possible to proceed with the solid
SnCl4:5H2O (as per the patents).
You should not need to go to the solid admittedly but when you have the solid you (sort of ) know where you stand.
(The SnCl2 coming originally from Tin + HCl, ie.OTC.)
I have since obtained a jar of SnCl4:H2O
Sorry for not posting for a whole day but the divorce papers arrived today and I had to look through them..... (OJ'ing )
Dann2
[Edited on 19-12-2007 by dann2]
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jpsmith123
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Well Dann2 today I tried to buy some 95/5 solder locally, and I couldn't find any; Lowe's didn't have it, Home Depot didn't have it (and I know they
used to carry it), and I didn't see it at Sears, either.
Maybe tomorrow if I get a chance I'll try some smaller hardware stores.
After all the work you've done in trying to use the metals...to no avail...well I don't think I'll even attempt to retrace your footsteps. What I'm
curious about is whether or not the 95/5 solder can be anodically dissolved in NH4OH and deposited from that solution, as per the process described in
the patent Rosco recently uploaded.
| Quote: |
Sorry for not posting for a whole day but the divorce papers arrived today and I had to look through them..... (OJ'ing )
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Yes I've found that women for some reason don't like to play second fiddle to things like perchlorate anodes.
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chloric1
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| Quote: |
Yes I've found that women for some reason don't like to play second fiddle to things like perchlorate anodes. |
Well, AFAIK from my experience is that is situations such this, it shows the true intelligence and neediness of certain women. Some can be
supportive, many not. There is the art of compromise( I call appeasement) if you are lucky enough to get a woman that even slightly submissive, then
you can show them how you could make money or hep your fellow man. But then again some women are just not reasonable enough to let a man breathe a
little.
[Edited on 12/19/2007 by chloric1]
Fellow molecular manipulator
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jpsmith123
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Well being that Christmas is coming, I think Dann2 just needs to get her something special...like maybe some nice titanium jewelry...heck he could
even coat it with DTO! How many women this year do you think will be getting earrings that can also make perchlorate?
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Twospoons
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The ones in the know will be demanding Pt earrings - none of this cheapskate DTO-Ti rubbish.
Helicopter: "helico" -> spiral, "pter" -> with wings
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Xenoid
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| Quote: | Originally posted by jpsmith123
Well Dann2 today I tried to buy some 95/5 solder locally, and I couldn't find any; Lowe's didn't have it, Home Depot didn't have it (and I know they
used to carry it), and I didn't see it at Sears, either.
Maybe tomorrow if I get a chance I'll try some smaller hardware stores.
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@ jpsmith123
I've just been discussing the situation here in NZ with Twospoons. The only place we have found here is an online electronics parts company. I think
this type of solder is mainly used in electronics, and will be the .8 - 1.0 mm dia. resin cored wire type!
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