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axehandle
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NaClO4 production using a Pt clad Ti anode and a Ti cathode.
I'm hesitant to start a new topic regarding chlorate production since there are so many already, but I'm doing so anyway. Moderators, move
this if I'm in error.
I've recently built a chlorate/perchlorate cell with 5 liter capacity, where the anode is a platinum clad titanium mesh and the cathode is pure
titanium.
The power is drawn from an old ATX PSU capable of 30A at +5V.
My goal is to start out with a saturated NaCl solution and end up with (mostly) sodium perchlorate.
I've just turned the cell on, and will report how it goes.
[Edited on 2004-4-28 by axehandle]
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t_Pyro
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I see you've already started using your new-found electrodes to the max! Approximately what is the electrode area of the anode, and what is you
current density at the anode?
Your setup looks interesting, but the cell elements can't be made out too clearly. Would it be possible to post a closeup of the setup?
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Saerynide
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Playing with the new toys already I see
Im guessing you drilled holes in the top of the jar for the electrodes right? Looks kinda like the wires come out the side in the pic.
Edit: Oooooh... the jar's all nicely filled with Cl2
[Edited on 28-4-2004 by Saerynide]
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axehandle
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Upgrades.
Here's a better picture. To answer your questions, I have no idea what the current density at the anode is, but the cathode is a Ti strip
approximately 150x8x1mm.
The electrode interdistance is approximately 20mm, which seems a lot more due to the optical properties of water in a glass cylinder...
After receiving some advice from chemoleo, I decided to heat the vessel. It's therefore now placed in a water bath on a thermostatically
controlled hotplate. The soluability of Cl2 in water rises drastically with temperature as well, I've just read.
Yes, the electrodes and the gas vent pipe go through drilled holes in the jar lid. Those diamond coated hole saws are awesome!
If it seems necessary, I'll buy a current regulated power supply (i.e. a car battery charger) today. I think the voltage drop is quite severe.
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t_Pyro
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If you're having problems with the voltage drop, it may be possible that the salt solution isn't concentrated enough. In fact, when I'm
done concentrating the salt solution, it has a slight milky white look to it (probably due to some fine suspended NaCl). The other possibility could
be that your power supply just isn't delivering. I've seen that before- manufacturer claims it can provide 25A at 5V, but it peaks out at
11A!
About the necessity to heat: The cell effficiency increases at high temperatures, but you shouldn't have to heat it separately. Just leaving it
to run on its own, the cell should reach upto 65<sup>o</sup> to 70<sup>o</sup>C, provided the current is high enough.
If you have a multimeter, you could monitor the current consumption of the cell. That should yield some answers.
[Edited on 29-4-2004 by t_Pyro]
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axehandle
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When I realized
that it would take weeks just to convert 1500g of NaCl into NaClO4, I put the project on hold, pending manufacturing/obtaining a set of HUGE PbO2
anodes, a large (50 liter) stainless steel vat used as a cathode, coolant pipes, a stirring system, and a 100% duty cycle welding transformer.
I gave up, the Pt anode is just too small. I want to produce at least 5kg of NaClO4 per week, and convert it to NH4ClO4.
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Saerynide
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Wow. What are you gonna do with all that?
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darkflame89
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5 kg of sodium chlorate a week!!??
Ignis ubique latet, naturam amplectitur omnem.
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axehandle
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Rocket motor experiments consume lots of fuel..... besides, half of it is for another guy.
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hodges
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Axehandle, how are you going to make sure that you don't have any chlorate (vs. perchlorate) in your product? Ammonium chlorate detonates
spontaneously. I would be scared to make ammonium perchlorate unless I was real sure of the purity of my chlorate.
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rikkitikkitavi
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http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...
you probably know of this site axehandle.
Therer is listed some analytical methods of analysis of chlorate content (which you always will have) in the perchlorate-however I have looked after
the chemicals in question used and they are not possible to get in SE. Not that I know of atleast.
fortunately it is easy to reduce chlorate f e x by SO2.
/rickard
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axehandle
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Thanks for the input. I have considered using magnetite as the anode, make huge amounts of NaClO3, then convert it to NaClO4 + NaCl using thermal
decomposion (keep for several hours at slightly above the MP of NaClO3 (248C)). Then I planned to use FeSO4 or sodium bisulfate (used in wine making
unless I'm mistaken) to destroy residual chlorate, then convert the NaClO4 to KClO4 or NH4ClO4 the usual way.
But where would I get pure magnetite... sigh.
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rikkitikkitavi
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you can use carbon anodes for ClO3-, but they will erode , making filtering of the solution necessary.
/rickard
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axehandle
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That's why I don't want to use graphite. Magnetite looks very promising. I imagine (it being magnetic) that one could construct an electrode
simply as a powerful electromagnet made out of a coiled mild steel 8mm rod, covered with a 20mm thick layer of magnetite. Perhaps mixed with a small
quantity of some inert binder.
Anyways, my trusty pottery supplier claims to have "black iron oxide", but lists it formula as Fe2O3. I've sent them an email pointing
out the impossibility of that. It should probably be "FeO.Fe2O3", but they are (luckily for me) not good at chemistry. The only two iron
oxides I know of that are black are FeO and Fe3O4. FeO is more or less explosive and highly unstable, so it's likely that their web catalogue has
a misprint. But I won't get any reply until Monday. *sniff*
I hate waiting.
[Edited on 2004-5-1 by axehandle]
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t_Pyro
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Er... Don't you think you set your sights a bit too high? 5 Kg of perchlorate a week? You could be rich in no time if you could sell that off!!
You might want to try coating your graphite electrodes with lead dioxide using a lead nitrate electrolyte, as mentioned on Wouter's page.
Graphite electrodes coated with lead dioxide in this manner can be used in place of platinum electrodes in a chlorate/ perchlorate cell.
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axehandle
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Quote: |
Er... Don't you think you set your sights a bit too high? 5 Kg of perchlorate a week? You could be rich in no time if you could sell that off!!
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More like: I'd save alot of money in notime. But you're right, perhaps I should (in the interest of science) turn capitalist on a small
scale. Could be meself a lathe or some other toy.
Quote: |
You might want to try coating your graphite electrodes with lead dioxide using a lead nitrate electrolyte, as mentioned on Wouter's page.
Graphite electrodes coated with lead dioxide in this manner can be used in place of platinum electrodes in a chlorate/ perchlorate cell.
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There's no way I'd get hold of lead nitrate, both lead salts and nitric acid are restricted here. Magnetite is supposed to work fine for
chlorates though, chlorates can be thermally decomposed to perchlorate and chloride, NaCl is cheap...
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chemoleo
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arrgh...
wasnt there another thread pointing out precisely how to get lead dioxide from lead and copper carbonate/acetic acid? Comon!!
You dont HAVE to have the nitrate, the acetate is fine... as shown by my very own experiment... why do I bother?
PS or am I misunderstanding something? It's late here...
[Edited on 2-5-2004 by chemoleo]
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axehandle
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It could be me misunderstanding something, I have a grade 9 hangover.
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axehandle
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Quote: |
arrgh...
wasnt there another thread pointing out precisely how to get lead dioxide from lead and copper carbonate/acetic acid? Comon!!
You dont HAVE to have the nitrate, the acetate is fine... as shown by my very own experiment... why do I bother?
PS or am I misunderstanding something? It's late here...
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Ah. No. I'm not abandoning the PbO2 idea, I'm just speculating idly about using Fe3O4 as an anode in a VERY big chlorate cell. The PbO2
would then be used in a chlorate-->perchlorate cell. Or, I'd build a chloride-->perchlorate cell using a huge PbO2 anode. I know
mind-reading is hard, I don't always explain how I think. The magnetite speculation was actually about trying the substrate-less PbO2 anode
manufacturing process using much more easily obtained Fe3O4 as a replacement, until I find a method that works. Then I would duplicate it using PbO2.
You have not helped me in vain, I just have a tendency to speculate wildly, not explaining why or what I'm speculating about...
Edit: I've just ordered 1kg of copper carbonate to experiment with.
[Edited on 2004-5-3 by axehandle]
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garage chemist
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I will soon purchase some platinum wire
(diameter: 0,3mm length: 45cm price: 30€. Quite a good deal.).
I will also buy a platinum coated Titanium anode when I have the money.
I've read that trace amounts of chloride can dissolve platinum when it's the anode! How severe is this problem? Does my NaClO3 need to be
free of chloride when producing perchlorates? I will use 99% pure NaClO3 (store- bought) as the starting material.
No NaCl, the process would take way too long.
Generally, which ions dissolve platinum when it's the anode?
Another question: axehandle, how did you make a non- corroding electrical connection to the Ti/Pt anode? I've been wondering about that for a
long time.
The Ti/Pt anodes that I sometimes see at Ebay are just Pt coated Ti wire meshes and look exactly like yours. They have no electrical connectors. Did
your anode have connectors, or did you have to make them?
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axehandle
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This was before I abandoned the Pt anode and decided to build a PbO<SUB>2</SUB> anode instead, but here goes: My pesky Pt-ized Ti anode
has a Ti plate with a hole through it welded to the Ti mesh. I made a connection simply by threading a copper wire through the hole in a few loops and
then winding it tight. Corrosion there is a non-problem since the connection will never be subjected to fluid from the cell.
If the connection were to be subjected to cell fluids, the only suitable connection material I know of is silver. The connection will corrode there
too, but the corrosion products are conductive so the connection won't fail.
From what little I've read, corrosion of the Pt is non-negligible when it's used in a chlorate cell and the chloride content gets low. Seems
the corrosion is minimal when used in a pure perchlorate cell. Don't quote me on this though, I could be very wrong.
[Edited on 2004-9-15 by axehandle]
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garage chemist
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I want to share this excellent link on the home production of chlorates and perchlorates, I'm sure that nobody posted it before (at least
I've never seen it before):
http://www.vk2zay.net/article.php/63
Very interesting!
EDIT: OK, it's not that big, I posted it before reading through it... but the rest of the site is also good.
[Edited on 21-6-2005 by garage chemist]
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SAM4CH
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Mjor Factor!!
What is the major factor which is respond of converting chlorate to perchlorate when we try to make perchlorate directly from chloride by
electrolysis, Is it current density at anode or chloride concentration (<10%), and when we use low current density on special anodes like MMO which
has optimum current density=(20A/ft2) and it is stable at low chloride concentration (>3000ppm Chloride) Can I get perchlorate!!?
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SAM4CH
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How can I make perchlorate from NaCl using pure platinum with out corrision? I have platinum plate 10*20 cm with 1mm thickness, it is very expensive
so please advise me!!
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jpsmith123
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In theory, in order to minimize platinum loss, you don't want to do a "batch" type process; rather, you want a "continuous" process.
So in practice you want to do it in two steps, where you first make chlorate (maybe using an immersed polyester bag filled with salt to maintain a
saturated NaCl solution, adding water as necessary), and then take your product chlorate and electrolyze that in the same manner.
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