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tentacles
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I finally got around to welding up a round shank anode- noone will remember but I was trying to use solid Ti rod (.625") with a flat milled on it. I
had very good success today spot welding the mesh to the rod after preheating the rod with a torch. Not sure precisely how hot I got the rod, but I
saw good penetration under the spots I welded.
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Swede
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Good deal Tentacles. Because Ti is slow to transmit heat, a lot like stainless, you can get a nice localized heating that definitely helps with the
welds. I've been using an area of slightly greater than 1 square inch for attachment of the mesh to the shank, and I think that should be adequate
for anything up to 100 amps.
Got any pics? 
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Bikemaster
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For the people who miss the really cheap mmo!!! laserred is now alive
http://cgi.ebay.com/EXPANDED-TITANIUM-MESH-STRETCHED-SCREEN-...
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bbartlog
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Would it be possible to use an electrically conducting ferrofluid as an anode (see for example US patent 4604229 for a description of how to
manufacture such a fluid)? It seems like the resistance might be too high (in the patent the example they give has a resistance of 100 Ohms/cm), but I
imagine that anode geometry, like the use of a thin layer floating at the bottom of a cell, could address that. Just seems like certain problems of
anode wear and/or blockage by oxidation products might solvable if a fluid anode could be used (like mercury, but in this case a magnetite/graphite
particle mix).
Of course it's possible that the surfactants, fluidizers and so on would be too vulnerable to chemical oxidation in this situation.
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watson.fawkes
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Quote: Originally posted by bbartlog  | | Of course it's possible that the surfactants, fluidizers and so on would be too vulnerable to chemical oxidation in this situation.
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Even the magnetite might be subject to oxidation. It's in a mixed +2/+3 crystal structure. I can't imagine
that the +2 iron wouldn't get oxidized to +3.
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hissingnoise
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Magnetite was used, and may be still, as anodes for the production of perchlorates.
It's rate of disintegration is higher than that for LD and its conductivity is on the low side but it was, at one time found to be fairly economical
on the large scale. . .
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dann2
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Hello and good afternoon Sir Hiss,
| Quote: Originally posted by hissingnoise | Magnetite was used, and may be still, as anodes for the production of perchlorates.
It's rate of disintegration is higher than that for LD and its conductivity is on the low side but it was, at one time found to be fairly economical
on the large scale. . . |
Where did you read that piece of (totally erroneous) information?
Dann2
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hissingnoise
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Well, Well! If it isn't our "little chlorates uber genius" from down-under!
Just for you, here's the appropriately titled; "Idiot's Guide"!
http://www.warezwally.com/files/Potassium%20Chlorate%20Guide...
And in case you can't find the word magnetite there. . .
http://www.pyroguide.com/index.php?title=Preparing_chlorates
[Edited on 21-11-2009 by hissingnoise]
[Edited on 22-11-2009 by hissingnoise]
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bbartlog
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Just searching Google Books for 'magnetite anode' will give some results that should (in aggregate) be pretty compelling, if for some reason you don't
find Wally and Wikipedia convincing (which would be understandable).
Anyway, I suspect that the relative difficulty of making ferrofluid compared to making a solid magnetite anode the size of a brick means that a liquid
anode of this type would be merely a curio -
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bbartlog
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Just searching Google Books for 'magnetite anode' will give some results that should (in aggregate) be pretty compelling, if for some reason you don't
find Wally and Wikipedia convincing (which would be understandable).
Anyway, I suspect that the relative difficulty of making ferrofluid compared to making a solid magnetite anode the size of a brick means that a liquid
anode of this type would be merely a curio -
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dann2
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All you need is Magnetite (me foot)!!!!!!
Hello,
Tutt Tutt!!
Terrible language.
Have you any references that show Magnetite was ever used "fairly economically on a large scale" to make Perchlorate, as you stated?
The refs. you give are a verbatim copy of the Geocities site (no mention of making Perchlorate in any sensible fashion with Magnetite), and the other
ref. is a verbatim copy of Wouter Vissers site on Chlorates/Perchlorates. He simply states that you can make Perchlorate with Magnetite. As we all
know you can make the stuff (Perchlorate) with DSA, Graphite, IRON!, Lead metal, Cobalt Oxide, Tin Oxide, ............but in a fashion that is of
little or no use to us.
Some info. here if anyone is interested in Magnetite Anodes.
See also GB 850,380 where it states that Magnetite will make Perchlorate at a current efficiency of 4 to 5%. Not very economical me thinks!!!!!!!!!
Primary refs. would be nice, in fact they would be fecken great. I think I speak for lots of folks in here when I say that we are all very interested
in making Perchlorate, with Magnetite, in a fashion that could be described as economical (thats economical for us, a much easier target to hit than
what industry would demand).
You need to calm down Hissing noise. If you continue to yield that sword Seaside Windmill in your usual wild and
frothing-at-the-mouth manner, y'll put yer own eye out.
Stop sending me U2U's as I don't read them (when coming from the 'Hissingnoise' instance anyways) as they are inclined to be a bit rude 
Dann2
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Xenoid
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Hissingnoise (what an appropriate moniker) - quit the bad language and abuse and put up or shut up with regard to the magnetite anode for perchlorate!
The "references" you quote above are nothing more than abbreviated rehashing of information on Visser's and Dann2's sites.
A perusal of the "Perchlorate Monograph" (Perchlorates their preparation, manufacture and use, Ed. Schumacher, 1960) reveals the only mention of
magnetite anodes for perchlorate to be a study by Ullmann in 1929 in which it is found to be unsatisfactory and only lead dioxide (with the exception
of various forms of platinum) was the only suitable alternative to pure platinum.
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hissingnoise
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Ok! So you guys think magnetite was never used successfully to manufacture perchlorates---is that it???
You really think that every manufacturer went out and bought sheets of polished platinum every time they wanted perchlorate?
And I apologise dann2, for the rudeness---next time I'll be less rude.
And Xenoid (strange name for a silly goose?), consider my puff-adder behaviour under reconstruction. . .
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dann2
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Hello,
| Quote: Originally posted by hissingnoise | | Ok! You really think that every manufacturer went out and bought sheets of polished platinum every time they wanted perchlorate?
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No, we don't. We know they also used Platinised Ti, alloys of Pt + Ir and Lead Dioxide. | Quote: Originally posted by hissingnoise | | And I apologise dann2, for the rudeness---next time I'll be less rude. And Xenoid (strange name for a silly goose?), consider my puff-adder
behaviour under reconstruction. . . |
You don't actually think I take it seriously?  It IS noisy though. If you
could make an effort at being less pre-teen so as to lessen said noise.
Where are the ref's, or do we take the statement, "Perchlorate's were made fairly economically on a large scale with Magnetite", as just some more
Hogwash.
Dann2
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hissingnoise
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Magnetite anodes were big (large-scale)!
I never said perchlorates were produced in large quantity. . .
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dann2
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Hello,
| Quote: Originally posted by hissingnoise | Magnetite was used, and may be still, as anodes for the production of perchlorates.
It's rate of disintegration is higher than that for LD and its conductivity is on the low side but it was, at one time found to be fairly economical
on the large scale. . . |
Have you any refs. to back up the claim above irrespective of the interpretation put on it.
Refs. please (ie. get a move on).
How big were the Anodes, who/where were they made and used. Where did you find out or learn of these 'facts'. If you don't have any refs. to back up
the claim (irrespective of the interpretation) I, (and I suspect others too!) will be presuming that both the claims that:
1)Perchlorate was made on a large scale with small scale Magnetite Anodes and found to be fairly economic or
2)Perchlorate was made on a small scale with large scale Magnetite Anodes and found to be fairly economic
(ROFL)
are indeed more Hogwash.
If you have no independent refs. you can always simply state that you have no independent refs. to back up the claim. I don't believe you, your taking
the piss.
Dann2
Lord help us all if the Perskovites appear 
[Edited on 22-11-2009 by dann2]
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hissingnoise
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I don't have a lot of free time since I've seen off a harmless but persistent rhinovirus, but when I find irrefutable evidence you'll be one of the
first to know---rest assured. . . !
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dann2
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Hello,
From above:
_________________________________________________________________
1)Perchlorate was made on a large scale with small scale Magnetite Anodes and found to be fairly economic or
2)Perchlorate was made on a small scale with large scale Magnetite Anodes and found to be fairly economic
__________________________________________________________________
Whatever you do, don't forget you are looking for info. on option 2 (as stated by yourself). Large scale Anodes (great big monster Magnetite Anodes
or a large amount of smaller ones) employed in a cell for small scale Perchlorate production. (LOL)
I'd wheel out the rolleye's but since you battleing with the common cold I will make an exception.
Good Afternoon.
Dann2
[Edited on 23-11-2009 by dann2]
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dann2
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Hello,
@Swede. There is a Bi Oxide + SnO2 Anode in the patent below (example three). It claims that it is useful for Chlorate and Perchlorate production. It
has not been tried before (patent was posted elsewhere on the board at some time or other). It would definately be worth a try. It's a no Lead, baked
only, possible Perchlorate Anode.
You will need hot HCl to etch Ti, SnCl4 (liquid) and Bismuth Nitrate.
You could probably use SnCl4:5H2O (a solid) and dissolve it in Alcohol + some conc. HCl. You could perhaps use Bismuth Chloride if you cannot get the
Nitrate.
You just brush on the solution to the Ti and bake. Put on about 6 coats (or whatever you wish).
Might be a break through!
SnCl4 (liquid) or SnCl4:5H2O (solid) can be had easily enough on ebay.com. You only need small amounts.
I tried using a Tin Oxide + Antimony Oxide Anode in a Perchlorate cell (pure Na Chlorate dissolved in water) for approx. 19 days. The solid extracted
after that time contained 69% Chlorate the rest was Perchlorate. Not a useful Anode but the Tin Oxide held up well for the 19 days. It would have
lasted much longer IMO but I put it into a Lithium cell and the Lithium cell seemed to erode it rapidly in approx. 24 hours. I was not really trying
to make a Perchlorate Anode from Tin Oxide + Antimony Oxide Anode just testing my coating/coating method to see how well it held up in a Perchlorate
cell as I was going to use it as an undercoat between Ti and LD.
There is a thread here on the Anode I was testing: Tin Oxide + Antimony Oxide Anode.
If you have an oven (you have) it is quite simple to do.
Keep it KISS. Don't be tempted to go down the 'Johnny Fortycoats + half the elements in the Perodic Table' road! (sorry about that )
Good Luck
Dann2
[Edited on 16-12-2009 by dann2]
Attachment: US 4272354 Bismuth_DTO perchlorate anode.pdf (253kB)
This file has been downloaded 807 times
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Rosco Bodine
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DuPont Elvanol 71-30 100% hydrolyzed PVA thickener
http://www.chemicalstore.com/navigation/detail.asp?id=PVOH2
You could actually use a very small amount of the antimonate
for example 1 or 2% of the total weight of the principally Bi doped DTO composition. Sb reportedly functions to decrease the grain size and densify
and toughen the coating as well as to increase the oxygen overvoltage, which are desirable and should enhance the anode coating durability. The
hydrosol precursor should yield a much higher quality DTO baked film than what is gotten from other precursor schemes, and it should build thickness
faster for a series of baked coats. For the first several coats it would probably be best to stick to the lower ~10% doping levels which result in an
optical quality pore free sealing film, in order to create a dense barrier layer protecting the substrate. A higher doped but less mechanically
perfect, yet more catalytically active coating can subsequently be applied as the working coating. The additional doping could be achieved by using
the higher levels of needed Bi in the form of a soluble complex of Bi added to the hydrosol, if indeed it is not practical to simply raise the
percentage of Bi in the described hydrosol.
This is a higher art for producing tougher baked coatings
than is likely to be achieved using chlorides precursors.
Oxalic acid is going to be a superior etchant for bare Ti.
There are a couple of reasons why oxalic acid is the preferred etchant. The surface effect has a physical property which enhances adhesion of
coatings. And there is a trace residue of Ti oxalate at the interface which on baking supplies carbon from charring and has a reducing effect upon the
TiO2 formed at high temperature, resulting in a conductive mixed Ti oxide at the interface which is also more capable of adsorption of dopants. For
these reasons, it is
justified to prefer oxalic acid as the etchant.
And a Co spinel or a mixed Co/Ni spinel would probably make a superior interface coat as the first baked primer coat,
one or two coats only, followed by the DTO.
In the famous words of Yogi Berra,
"This is like deja vu all over again"
Attachment: US6777477 Bi2O3 doped SnO2 via ammonia soluble derivative.pdf (67kB)
This file has been downloaded 687 times
[Edited on 17-12-2009 by Rosco Bodine]
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Xenoid
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Here's a neat pool chlorinator MMO electrode assembly I recently acquired. It is notable for its unusual design which I haven't come across before.
Firstly it uses solid plate electrodes (140 mm x 47.5 mm) these comprise two monopolar anodes and two monopolar cathodes. Each set of these is
connected by a strap at the bottom of the assembly. Between each anode and cathode there are two unconnected bipolar electrodes. There are ten
electrodes in total and the total thickness is about 3.5 cm giving an inter-electrode distance of less than 3.5 mm.
All the electrodes are MMO coated and there is no polarity marked on the connectors, this suggests it was run in an automatic polarity switching
"bipolar" chlorinator. I thought the design was perhaps quite old but in fact it is date marked 11 - 1 - 2005.
There is a little erosion of the MMO around the edges, but it still appears quite serviceable, I think I will pop it in a chlorate cell and see how it
performs. That's about 660 cm^2 of MMO anode in a very compact unit
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tentacles
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Looks like it may have been removed from service because of that short or near short from one of the plates warping?
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Xenoid
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| Quote: Originally posted by tentacles | | Looks like it may have been removed from service because of that short or near short from one of the plates warping? |
Hi tentacles - when I saw how the photo had come out I thought someone might mention that! In fact, none of the plates are touching, I don't think
that plate is warped from use either. That near 1 mm thick plate is really tough and I think the corner was bent during a sloppy guillotining process
- probably made on a Friday afternoon.
Many of these units are removed during routine servicing or for some other problem with the pool other than the chlorinator. The pool contractor makes
a nice little profit when they are replaced. Most of the ones I have obtained still have usable MMO. That said, I did come across one that was
virtually held together with "salt" encrustations and crumbled in my hands.
I have discovered a slight problem with the one above, the Ti strap is cracked on one side where it is spot welded to the Ti bolt. This damage was
caused by the service guy's rough handling when removing the bolts from the plastic lid - which he wanted to retain. I need to get a spot welder to
fix it otherwise current handling will be somewhat limited.
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dann2
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Hello,
Another gem from the dustbin Xenoid!
At 200mA per square cm of actual Anode area in a Chlorate cell, thats 660/2 x 0.20 = 66 Amps for this Anode. You will need to put more connections
going to it to carry all that current. When used as a pool chlorinator it carries damn all.
Would perhaps an AC have been applied to it when it was used as a pool Chlorinator?
Dann2
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Swede
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Nice find! Xenoid, if the crack you mention is simply from the bolt hole to the periphery, I doubt it would limit current, especially if you used a
washer of Ti or 316 stainless to compress and form a nice connection. If that's not where the crack is, then ignore!
If the crack is elsewhere in the strap, a doubler of Ti could be spot or TIG welded on to carry the current. It is hard to do much work with
electrochemistry without some sort of welding apparatus.
When I was corresponding with deNora, they specifically asked if I wanted bipolar mesh; AC capable MMO that is used to self-clean the structure. I
said "No, the cheaper DC only stuff is fine for my needs." It lends support to the notion that most of the advanced pool chlorinators made these
days, especially those controlled by advanced microprocessor power supplies, are bipolar. I don't know why one would want or need bipolar material
for what we do, but it is interesting anyhow.
If you wanted to, it shouldn't be hard to straighten that little warp with a pair of fine pliers.
[Edited on 20-12-2009 by Swede]
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