making potassium (per) chlorate

[pdfbq]

1339090057[/url]' post='96234']

I'm not as familiar with the details of how all this works as the rest of you, but perhaps running at a more dilute concentration of chlorate could prevent excessive perchlorate crystallization near the electrodes.

I do not know if the Pt anode likes this.

 

I think the only reason one would use KClO3 as a starting point for perc is the Na pollution.The double displacement from NaClO4 to Kperc is fast and easy.

My experience is that the removal of the NaCl is easy as well. This because the high solubility of the NaCl and the low solubility of Kperc. Recristallize 2 times is enough. I test with silver nitrate.

 

If you would make Kperc the Kchlorate way you have to chemically destroy the leftover chlorate and the need to recristallize anyway to remove the K2SO4 OR recristallize several times to get rid of the KClO3.

 

To harvest a big crop of perc the Kchlorate way you need a huge cell due to the not so high solubility of Kchlorate and all the problems that come with a big cell like keeping it hot, keeping it mixed and not have the anode coverd with Kperc.

 

To harvest a big crop of perc the Nachlorate way a 2 liter cell can already give you 1.5 kilo of perc in some days.

Edited June 17, 2012 by pdfbq

[WSM]

I do not know if the Pt anode likes this.

I think the only reason one would use KClO3 as a starting point for perc is the Na pollution.The double displacement from NaClO4 to Kperc is fast and easy.

My experience is that the removal of the NaCl is easy as well. This because the high solubility of the NaCl and the low solubility of Kperc. Recristallize 2 times is enough. I test with silver nitrate.

If you would make Kperc the Kchlorate way you have to chemically destroy the leftover chlorate and the need to recristallize anyway to remove the K2SO4 OR recristallize several times to get rid of the KClO3.

To harvest a big crop of perc the Kchlorate way you need a huge cell due to the not so high solubility of Kchlorate and all the problems that come with a big cell like keeping it hot, keeping it mixed and not have the anode coverd with Kperc.

To harvest a big crop of perc the Nachlorate way a 2 liter cell can already give you 1.5 kilo of perc in some days.

 

The home remodel is slowing down so I'm starting to catch up with my reading of these posts.

 

For potassium perchlorate:

 

A "big cell" doesn't need to be more than 20 liters (about 5 gallons). "Keeping it hot" is the job of the electrodes, and if they're sized properly and matched well to the power supply, it's almost automatic.

 

As to "keeping it mixed", there are several methods and any one or a combination of them will assist in making this happen. There is natural heat flow with convection currents, mechanical stirring (of several types) and bubbling air has been suggested. With the bubbling air approach, a delicate balance must be made between enough air flow to discourage crystals from forming in the electrodes but not enough to interfere with the function of the electrodes by keeping the solution away from them.

 

Bubbling air (in a potassium chlorate cell) would probably be better at stirring things if the air were heated so it doesn't cause crystals to jam the air tube. I've experienced this problem first hand and I think Swede has recorded a similar experience in his blogs.

 

Thanks for the thoughts, pdfbq.

 

WSM

[pdfbq]

You will not heat a 20 liter cell with a $35 pt anode. So extra heating and extra stiring with its own problems.

I would say keep it simple. It is difficult enough!

 

 

[WSM]

You will not heat a 20 liter cell with a $35 pt anode. So extra heating and extra stiring with its own problems.

I would say keep it simple. It is difficult enough!

 

I'm hoping I can even heat 2 liters with a $35 Pt anode! I wonder if it can do anything at all (which still has to be proven), and why I call it a $35 gamble.

 

Certainly a 20 liter chlorate cell with an MMO anode and titanium cathodes will heat by itself just fine (given they're a proper match with all the other equipment needed to do the job).

 

WSM

[mikemortar]

has anyone tried using aluminum as anodes?, Ive tried it and it did start bubbling and steaming quickly there was no smell of chlorine

 

I have indeed synthesized chlorate and perchlorate. buy mmo anodes and cathodes they actually stand up better then platinum and they are cheaper. i will post a link the the seller i used. the inside is made from ti. when you cut you plates try not to scratch off the coating, as it will no longer conduct electricity. the ti exposed to the chloride solution will turn to an oxide and no longer conduct but it also will to dissolve or oxidize further. here is the link to mmo plate http://www.ebay.com/itm/EXPANDED-TITANIUM-MESH-STRETCHED-SCREEN-MMO-COATING-/330752793032?_trksid=m7&_trkparms=algo%3DLVI%26itu%3DUCI%26otn%3D3%26po%3DLVI%26ps%3D63%26clkid%3D166376498534528116&_qi=RTM1084480. you want to use as high amperage power supply as possible. i will post a link to a calculator if possible. what you tried to light was most likely just a chloride not chlorate. if you potassium chloride is white it is most likely pure enough to use. if it is red or you don't fell it is as pure as you want just do a simple recrystallization. if you don't know how to do that here is a link to the basics.http://www.youtube.com/watch?v=uVA0rK_VITY , and chlorate calculator http://www.vk2zay.net/calculators/chlorates.php. to prepare the solution heat up water preferably distilled water to a boil and dissolve the most chloride into the boiling water let cool to about 125f to 150F stain through filter to remove solids put remaining liquid in you chlorate cell. run for recommend time for weight of chloride used. to get wright of chloride used subtract the weight of the dry solid you got from straining it through the filter from you first weight. the reaction takes place best at 140F. the gasses given off by this reaction are corrosive and flammable. so bubble the resulting gasses through water to react with chlorine and to prevent a flash back. make sure the gasses are vented away from people animals and open flames or sparks. once reacted take the solution and filter it through filter paper and run cold water over it to wash off any chloride or hydrochloride. make sure that the water is almost freezing to not wash away the chlorate. you will be left with potassium chlorate kclo3. you most likely want perchlorate chlo4 so dissolve in h202 and recrystallize from you cell you will have some perchlorate too but in order to make sure it is all perchlorate you must react the chlorate. you will want to look up the specifics on the chlorate to perchlorate as i have not done it in a while. oh yea and ph you chloride solution with hcl make sure it is no higher that 8 and no lower then 6. this prevent the formation of hydrochloride. as for you cell design do some thing like this http://wn.com/%5BHD%5D_Potassium_Chlorate_Cell find a good power supply and then tell me it's specs in a pm i will tell you the spacing for you electrodes they should go about 2/3 of the way into you solution. the contestant has to be non conductive non reactive and preferred clear and it has to be air tight. you can get those jars a wallmart it is what i use the tubing for you blubber can be bought at wallmart the electrodes ebay power supply ebay or you might have one mine is 12v dc 5 amps. any other question just send me a pm or find me in the chat room. i do not own any of those links.

[pdfbq]

1340642701[/url]' post='96936']

I'm hoping I can even heat 2 liters with a $35 Pt anode! I wonder if it can do anything at all (which still has to be proven), and why I call it a $35 gamble.

You dont need to heat a NaClO3 cell to keep the NaClO3 in solution.

 

I do not have exactly that $35 anode, I have those from Ebay that shipped from Bangkok but they are the same type, for gold plating. I have 3cm by 5cm and they pulled IIRC about 7 amps over 5.2v.They made my cell unisolated warm and I made a lot of perc with it. I would call that proven .

 

The only challenge left for me is how to avoid as much as possible erosion of the Pt.

 

Personally I have two NaClO3 -> NaClO4 questions.

1. Is some NaCl pollution at the start harmfull?

2. When to stop and how to detect when to stop?

 

My experience so far says that it is not that harmfull for your anode if there is a little bit NaCl around at the start. When to stop is the challange i believe. My cell had the strange behaviour at the end that the current went up dramatically. As with chlorate the current slowly decreases when a cell is running but in my perc cell the current rose at the end. Almost no chlorate left then but I believe I run them too long.

Edited June 26, 2012 by pdfbq

[Mumbles]

... you most likely want perchlorate chlo4 so dissolve in h202 and recrystallize from you cell you will have some perchlorate too but in order to make sure it is all perchlorate you must react the chlorate. ....

 

Have you actually tried and confirmed this works? I've been under the impression that H2O2 isn't strong enough to do the final oxidation.

[Potassiumchlorate]

Also at least here in Europe H₂O₂ is a hard-to-get chemical in many places. Where I live I think you can theoretically buy 50% or even 60%, but nothing stronger than 17.5% is available for private citizens. That means that 50% or 60% is legal but that the suppliers themselves put restrictions on what they sell.

[mikemortar]

Have you actually tried and confirmed this works? I've been under the impression that H2O2 isn't strong enough to do the final oxidation.

yes it does work i have done it before i might post a how to on it. as of the heat even if there is some pottasium chloride that has not dissolved as the reaction continues and forms Kclo3, Kclo4 it will allow for more chloride to dissolve because the solution is not as saturated. ans from what i have done the best way is not to start with table salt. because if you do you use almost as much KCl but you have to do an other synthesis and recrystallization to get the same purity. i would recommend not starting with NaCl. i see i spelled kclo4 chlo4 sorry. if you do the electrolysis right most of it will be kclo4 but you will always have some kclo3 you can tell by the shapes of the crystals. you can use 3% h2o2 and get it work it is just a little harder i tend to use between 20% and 35%. i get it from hydroponics stores. Make a solution of 1/2 strength of water and Kclo4(if you are using 3% do this with strait 3% h202) then add the same volume of h202 (if you use 3% do this again or make it 1/4 maximum solution.). gently boil this down to 1/4 the size of the size. you do not want to see many bubbles. let sit for about 2 hours at room temp to let any reaction to complete. cool strain and wash then dry you Kclo4 crystals. they should be upwards of 98% you can recrystallize it if you are not happy with your purity. i would recommend to do so at every step at least with a little of you chemicals so you know what each one looks like. for example your KCL should look like little cubes i have seen them as large as 10mm cubes. hope this helps. i have done this lots of times i have been doing this way before i was even into pyro. it is actually rely simple. again if you want me to do a complete how to i can and will just say so. i also see my most important link did not work so here it is again http://www.vk2zay.net/calculators/?body=chlorates.php

Edited June 26, 2012 by mikemortar

[Swede]

Hi guys - I've read the last few pages. It's great to see how many people are interested in this process, and how far it has come from the common salt-encrusted pickle jars with corroded copper wires with 75 grams of chlorate after 3 weeks of electrolysis.

 

With MMO, a decent cell, and an adequate power supply, output can be measured in kilograms per week, easily, especially when a decent attempt is made to control pH. More on that in a bit...

 

Is Tentacles still active? He and I did a lot of brainstorming, and came to some good conclusions. First, it's great to see all of the PVC being used in construction. So far, my solvent-welded PVC tank has been bullet-proof. The interior dye has been leached, the plastic a bit bleached, but the integrity is perfect. Something to remember and possibly consider - CPVC is preferable, as it is engineered to handle higher heat, but it is sooo much more expensive than PVC. PVC pipe is rated for performance WHILE PRESSURIZED, and the reality is, our cells see no real pressure, so my gut feel is that standard PVC heavy-wall will in fact withstand high temps without mechanical failure.

 

After gluing that 25 liter square cell together from sheet PVC, I swore I'd never do it again. Total PITA. Thus came the notion of using sections of large diameter PVC pipe as a vertical tank, which I think is a superb idea. It's great seeing it done here.

 

I still like the notion of a "bucket cell adapter", and the example I have, kind of a test rig, works really nicely. We know HDPE is NOT the best material, but the common and cheap 5 gallon HDPE buckets + lids will last for several runs at least, and with a bucket cell adapter, all you need to do is jig-saw a rough rectangular cutout on the lid, mount the bucket cell adapter, which uses titanium hardware, fill the bucket, put the lid on, and apply power.

 

http://www.5bears.com/perc/bca04.jpg

 

http://www.5bears.com/perc/bca10.jpg

 

http://www.5bears.com/perc/bca12.jpg

 

The seal is a length of viton cord. Note the built-in tube fittings of PVDF, which (along with PTFE & PVC) are the only materials suitable for intimate contact with electrolyte.

 

Agreed that the flat straps traditionally used suck. They are very hard to mount. Any future electrodes I make will be of the tubular-shanked variety, filled with tin or lead. Better current capability, and ridiculously easy to mount.

 

Acid: My original setup used a lab-grade dosing pump and an electronic timer. Total overkill. I've been looking at simple gravity-fed systems for drip, like a hospital IV. There are gadgets called "IV regulators" that allow the user to simply "dial-a-drip" and are calibrated for rates that would be perfect for our work. I just picked up a few and will take some pictures. After tons of experiments, we have determined what acid delivery works, based upon current flow, so the need to tediously check pH 8 times a day is generally gone, thank goodness.

 

Oh boy, I've got a lot of ideas I want to toss out. Of course, the process to perchlorate is still not as refined at our level as is MMO --> chlorate. It'd be simple if we all had $2,000 for a nice Pt anode, but that's out of reach for most people. And even Pt erodes - perchlorate factories have to recover it chemically to be economically viable.

[pyrojig]

I too love the idea of the tubular shanks. It is pure genius!!

The ease of adjustment , mounting ,conductivity, and sealed qualities, make it a winner.

 

Im gonna work on taking from your IV drip idea and build a ph controlled sys like that. One question of concern though: when the system hits the efficient stage where acid is no longer needed in such volumes ,how would you go about adjusting a "dialed in " drip setup? My runs needed near to none acid at the 2/3 run mark. It seemed when the chlorides where all in solution and converted to strong bleach , the need for acid / ph control is minimal .There where days where a whole 24h period went safely w/o acid, while maintaining a "7" ph.

 

You where saying in your blogs that the Pb anode you coated did in fact work for perch. production..What was the final outcome of that? If a amateur could coat his own mmo electrodes with this plating process , it would save the need to spend large $ on perch electrodes.

[Swede]

We went in circles over pH control, from none, to theoretical closed-loop systems using a pH probe to monitor. The problem is the inevitable poisoning of the probe in a closed loop. Even a high-grade probe will drift badly in less than a day, and potentially be ruined in short order.

 

How do the factories do it? I don't know. Since they make TONS per run, the loss of a $200 probe might not be a big deal, financially. Or they may use a special probe that is immune to poisoning. I know they exist, but they approach $1,000. My guess is that they simply KNOW exactly how much HCl they need, over time, to maintain 6.8

 

For several runs, I checked pH several times a day, which was a real pain, and like you, saw that the acid demand dropped significantly at a certain point in the run. The rule of thumb became to reduce acid delivery by 1/3 when crystals form in a chlorate cell, and even then, that may be too much acid.

 

For a reasonable current-based pH control, add to the cell 0.057 ml of concentrated (32%) HCl per ampere, per hour, with the HCl delivery reduced by 33% after the chlorate crystals begin to form.

 

Given these numbers, a cell at 20 amps will need 1.14ml/hour of conc. HCl, and numbers like this are smack in the range of what a patient needs using IV meds in a hospital. And we can always dilute the HCl, add chloride ions to it, and turn it into a combined acid delivery/top-off system.

 

Anyway, my thought with a simple drip is to manually intervene at an appropriate point. We know the current necessary to convert a given batch; we have the math. And given current, we can derive the HCl needed.

 

I think we can refine the above rule of thumb quite a bit more, and also create a rules set for 100% aqueous sodium cells.

 

I'll get some pics of that IV stuff I snagged on eBay. It's really cheap and should be 100% compatible with HCl.

Edited July 18, 2012 by Swede

[WSM]

I too love the idea of the tubular shanks. It is pure genius!!

The ease of adjustment , mounting ,conductivity, and sealed qualities, make it a winner.

 

Im gonna work on taking from your IV drip idea and build a ph controlled sys like that. One question of concern though: when the system hits the efficient stage where acid is no longer needed in such volumes ,how would you go about adjusting a "dialed in " drip setup? My runs needed near to none acid at the 2/3 run mark. It seemed when the chlorides where all in solution and converted to strong bleach , the need for acid / ph control is minimal .There where days where a whole 24h period went safely w/o acid, while maintaining a "7" ph.

 

You where saying in your blogs that the Pb anode you coated did in fact work for perch. production..What was the final outcome of that? If a amateur could coat his own mmo electrodes with this plating process , it would save the need to spend large $ on perch electrodes.

 

Hi pyrojig,

 

One idea that comes to mind regarding the changing demands for acid in a pH controlled system is to feed the acid dispersing tube from two ports; one with the minimum flow, running continually; and the second one with a higher rate of flow but dialed down (to zero) as the demand is reduced.

 

I think this may work with the IV and other systems as well.

 

Any thoughts... ?

 

WSM

Edited July 20, 2012 by WSM

[pyrojig]

Hi pyrojig,

 

One idea that comes to mind regarding the changing demands for acid in a pH controlled system is to feed the acid dispersing tube from two ports; one with the minimum flow, running continually; and the second one with a higher rate of flow but dialed down (to zero) as the demand is reduced.

 

I think this may work with the IV and other systems as well.

 

Any thoughts... ?

 

WSM

 

My thoughts .........>>>>>> Lets build it!!!!! I think it would be a fantastic / simple setup , and well worth the efforts .

[WSM]

My thoughts .........>>>>>> Lets build it!!!!! I think it would be a fantastic / simple setup , and well worth the efforts .

 

Well, alright then...

 

I just got the first few IV drip control units today. I'll see what I can do to make this happen.

 

More later...

 

WSM

[WSM]

I've done some spot-welding tests on 0.050" titanium sheet and 0.375" blocks of titanium. The purpose is to build a solid structure for "boxing" the cathodes around the anode for the fullest use of the anode surface.

 

In testing the welding of two plates to a pillar, the first weld broke right apart. The second attempt was a longer duration weld, but it still wasn't strong enough. On the third try, I welded the two plates to the solid pillar, flipped it over and welded them again. This time I got a solid weld that is holding very well.

 

An unusual thing I noticed is that the thicker the piece of titanium, the hotter it gets when spot welding. In retrospect it makes sense because of the highly resistive nature of titanium (if copper has a conductivity rating of 100, titanium's conductivity is 3.1 by comparison). So the thicker piece has more resistance than the thinner sheet metal and it heats more than the sheet. Also under pressure it deforms more, so the pressure should be regulated while spot-welding.

 

WSM

[dagabu]

When does the RTR kit come out? I'm in for one.

 

-dag

[WSM]

When does the RTR kit come out? I'm in for one.

-dag

 

Well dag, I'll tell ya,

the first one I'm making is spoken for; but the next one I make, I'll give you the first crack at it.

 

WSM

[dagabu]

Well dag, I'll tell ya,

the first one I'm making is spoken for; but the next one I make, I'll give you the first crack at it.

 

WSM

 

I'll settle for one once you get it all straightened out and its ready for prime time. I am in no hurry, its going to be for the Zombie-gedden.

 

-dag

[pyrojig]

I'll settle for one once you get it all straightened out and its ready for prime time. I am in no hurry, its going to be for the Zombie-gedden.

 

-dag

 

Uh oh, another Zombie killer loose!!!! Will there be blood involved ?

Maybe a reactive Zombie ?

 

 

@WSM

HMMM, wonder who that lucky fellow is ....

Edited July 24, 2012 by pyrojig

[Swede]

H2O2 does not make perchlorate... Shamelessly stolen from somewhere, I don't remember, might have been SM.

 

Some research that should completely put to rest any questions about the reaction between potassium perchlorate and hydrogen peroxide:

 

Chlorates, when heated to moderate temperatures, disproportionate into perchlorate and chloride.

4NaClO4 --> NaCl + 3NaClO4

Fowler and Grant found that on heating chlorate with silver oxide that the chlorate was completely converted to perchlorate without loss of oxygen, metallic silver also forming.

J. Chem. Soc. 57, 272 (year 1890)

 

A solution containing one gram sodium chlorate, 1 cc sulfuric acid (specific gravity 1.82), and one gram potassium permanganate in 100 cc water was boiled for 30 minutes. The solution showed no perchlorate present.

 

Hydrogen peroxide failed to oxidize chlorate to perchlorate under alkaline, neutral, or acidic conditions, although minute traces of perchlorate did form under acidic conditions.

“Electrolytic Formation of Perchlorate” C. W. Bennett, E.L. Mack. Chemical Engineer, volume 23, p206

 

Alkaline

A boiling solution of sodium peroxide failed to oxidize chlorate to perchlorate.

 

A solution containing one gram sodium chlorate and 1cc ammonium hydroxide (specific gravity 0.90) in 15 cc hydrogen peroxide (30%) was boiled for 30 minutes. Analysis of the solution failed to show any traces of perchlorate, thus showing that alkaline hydrogen peroxide is not a sufficiently powerful oxidizer to convert chlorates to perchlorates.

 

Oxidizing Power of Alkaline Hydrogen Peroxide

Although alkaline solutions of peroxide failed to oxidize chlorate, it is nevertheless worth mentioning the high oxidizing power of such solutions. Although alkaline peroxides (such as CaO2) are stable in the absence of water, hydogen peroxide slowly decomposes in aqueous alkaline solution. A mixture of hydrogen peroxide and ammonium hydroxide (in a 1:3 ratio) acts as a reactive oxidizer, which can attack organic compounds and elemental carbon. The reaction rate is negligible at room temperature, but when heated to 60°C the reaction becomes vigorous and self-sustaining. Such solutions are sometimes known as "base piranha". With a 1:1:5 volume ratio of NH4OH, H2O2, and H2O, respectively, the half-life times of peroxide were 4 hours at 50°C and 40 minutes at 80°C. "Reaction of Ozone and H2O2 in NH4OH Solutions and Their Reaction with Silicon Wafers" Japanese Journal Applied Physics. 43 (2004) pp. 3335-3339. Magnesium hydroxide inhibits the formation or reactive radicals in alkaline solutions of hydrogen peroxide, interrupting the free radical chain reactions by catching the superoxide anion radicals. Zeronian SH & Inglesby MK (1995) "Bleaching of cellulose by hydrogen peroxide". Cellulose 2: 265-272.

 

Nuetral

One gram of sodium chlorate was dissolved in 15 cc hydrogen peroxide (30%) and the solution evaporated to dryness on the water bath. The residue was dissolved in a second 15 cc portion of hydrogen peroxide and again brought to dryness. After dissolving in water, and analysis was performed. This experiment showed that chlorate in neutral solutions is not oxidized to perchlorate by 30% hydrogen peroxide.

 

Acidified

One gram sodium chlorate was dissolved in 25 cc of hydrogen peroxide (30%) which had previously been acidified wih 1 cc sulfuric acid (specific gravity 1.82). The solution was boiled for one hour. Soon after the solution had reached he boiling point a yellow gas was evolved. This was at first thought to be chlorine but more careful examination showed it to be a mixture of chlorine dioxide and chlorine. Analysis showed small traces of perchlorate had formed. This experiment showed that chlorate, through the action of acidic solutions of hydrogen peroxide, is largely converted to chloride. A considerable amount of chlorine and chlorine dioxide is evolved at the same time. Acidic solutions of 3% hydrogen peroxide also were shown to reduce chlorate to chloride.

 

It has been suggested that in the above reaction the intermediate formation of small amounts of hydrogen chloride interferes with the reaction, catalytically causing decomposition of the chlorate. Chlorine is known to react with hydrogen peroxide to form hydrochloric acid and oxygen gas. The hydrochloric acid thus formed would attack the remaining chlorate, the products of the reaction being chlorine and chlorine dioxide, the chlorine then reacting with more hydrogen peroxide to again form hydrogen chloride.

 

Reaction of concentrated sulfuric acid with sodium chlorate did not produce any perchlorate, but it has been reported by other sources that perchlorate is indeed produced. This may be due to different acid concentrations and ratios of reactants.

 

The reaction between solutions of chloric acid (HClO3) and hydrogen peroxide does not have any appreciable reaction rate until a temperatures above 70degC. (note that perchlorate is not a reaction product in the decomposition reaction, although it may be likely that traces are formed). experiments conducted by Sand, published in Zelt phys. Chem.,50, 465 (year 1904)

 

I've tried a couple of oxidizing methodologies to chemically convert chlorate to perchlorate. The only one which made any perchlorate at all was O3. A continuous bubbling of ozone from an ozone generator, through a 100ml or so sample of saturated KClO3, produced traces of perchlorate xtals in the end of the bubbler tube. That setup would have taken months to make a couple of grams of KClO4.

 

In the end, if there IS a chemical process, it's probably going to be not economical at all. It makes little sense to pursue any other method besides electrolytic or thermal decomp.

[Swede]

I was doing a bit of back reading today. There are some great thoughts and some excellent experimentation going on... it's great to see!

 

One of the ?? that seems to appear repeatedly is temperature. For a chlorate cell, higher temps generally improve efficiency. But if a cell is massive and the power supply modest, the entire system will probably stabilize at a lower than desirable temperature. What to do?

 

Remember there are two pathways to chlorate. Direct oxidation at the anode, and the more prevalent bulk reaction that takes place chemically away from the electrodes. If high temps favor the former, then a PVC sleeve - picture a section of pipe, open top and bottom, surrounding the electrodes - would definitely create a favorable higher temperature around the electrodes. This would have the added benefit of creating a circulation pipe. As the gases evolve, they'll draw liquor from below and pipe it up and out. However, my gut feel is that high temps also help the overall bulk reaction. If that is the case, then the entire cell should be maintained at a higher temp.

 

It all depends upon the power, the cell volume, and the cell materials. Normally, I've found that even larger cells with modest current get nice and warm. So much so, that my old tower cell got TOO hot, and I immersed the entire thing in a big tub of water. Let me put it this way - I've never worried about my cell being too cool... I was always working to cool them off a bit.

 

If someone DID need to warm up a cell, I think the easiest way to do it would be to insulate it. Wrap some foam rubber or fiberglass insulation around it, and I think even 10 amps in 5 gallons would eventually take it up to a good temperature.

 

Power supplies... if a guy can find a power supply capable of CC (constant current) operation, that'd be the way to go. The ideal PS would be 0 to 12 V, with CC/CV operating modes. But they can be expensive and/or hard to find. Be careful with eBay and similar... I'd NEVER EVER buy a PS that is not guaranteed to work. Don't take the chance. But if a CC unit cannot be found, surplus industrial 5V supplies are super common, and reasonably cheap. Look for one that has a voltage trimmer potentiometer - these can allow one to tweak the voltage a tiny bit, usually in a small range, say 4.6 to 5.4V, and this is good, a 1/2 V can make a big difference in current, and allow one to tweak for best operation.

 

5V 50A trimmable PS $38

 

5V 100A Switcher $130

 

5V 75A $99

 

Here's a nice one, the guy has 10 available, NOS

5V 100A

 

Doing a modest bit of eBay browsing, it seems that prices are jacked up a bit from 2008 or so. I got those 0-10V 100A CC jobs for less than $100 each.

 

Finally, want to make a kilo a day?

5V 300A monster, looks new, $180

 

Anyway, just some thoughts on a slow day.

Edited July 25, 2012 by Swede

[WSM]

I was doing a bit of back reading today. There are some great thoughts and some excellent experimentation going on... it's great to see!

One of the ?? that seems to appear repeatedly is temperature. For a chlorate cell, higher temps generally improve efficiency. But if a cell is massive and the power supply modest, the entire system will probably stabilize at a lower than desirable temperature. What to do?

Remember there are two pathways to chlorate. Direct oxidation at the anode, and the more prevalent bulk reaction that takes place chemically away from the electrodes. If high temps favor the former, then a PVC sleeve - picture a section of pipe, open top and bottom, surrounding the electrodes - would definitely create a favorable higher temperature around the electrodes. This would have the added benefit of creating a circulation pipe. As the gases evolve, they'll draw liquor from below and pipe it up and out. However, my gut feel is that high temps also help the overall bulk reaction. If that is the case, then the entire cell should be maintained at a higher temp.

 

It all depends upon the power, the cell volume, and the cell materials. Normally, I've found that even larger cells with modest current get nice and warm. So much so, that my old tower cell got TOO hot, and I immersed the entire thing in a big tub of water. Let me put it this way - I've never worried about my cell being too cool... I was always working to cool them off a bit.

 

If someone DID need to warm up a cell, I think the easiest way to do it would be to insulate it. Wrap some foam rubber or fiberglass insulation around it, and I think even 10 amps in 5 gallons would eventually take it up to a good temperature.

 

Hi Swede,

 

If you're serious about using a vertical polymer tube to promote heat around the electrodes and fluid drafting, have I got a deal for you. A year or two ago I acquired a length of PVDF tube 90mm OD with a 2.8mm wall.

 

I believe it would be ideal in that application. Please PM me for more details.

 

WSM

Edited July 26, 2012 by WSM

[WSM]

Hi Swede,

If you're serious about using a vertical polymer tube to promote heat around the electrodes and fluid drafting, have I got a deal for you. A year or two ago I acquired a length of PVDF tube 90mm OD with a 2.8mm wall.

I believe it would be ideal in that application. Please PM me for more details.

WSM

 

Here are two photos of a piece about 13" long:

 

 

The OD is a bit over 3.5" and the ID over 3.25" and it would work admirably in the application Swede mentioned . The inside surface is very smooth but the outside surface shows minor striations along the length, making me think this tube was formed by an extrusion process. The whole piece of PVDF tubing is very rigid and high purity.

 

WSM

[WSM]

I've done some spot-welding tests on 0.050" titanium sheet and 0.375" blocks of titanium. The purpose is to build a solid structure for "boxing" the cathodes around the anode for the fullest use of the anode surface.

In testing the welding of two plates to a pillar, the first weld broke right apart. The second attempt was a longer duration weld, but it still wasn't strong enough. On the third try, I welded the two plates to the solid pillar, flipped it over and welded them again. This time I got a solid weld that is holding very well.

An unusual thing I noticed is that the thicker the piece of titanium, the hotter it gets when spot welding. In retrospect it makes sense because of the highly resistive nature of titanium (if copper has a conductivity rating of 100, titanium's conductivity is 3.1 by comparison). So the thicker piece has more resistance than the thinner sheet metal and it heats more than the sheet. Also under pressure it deforms more, so the pressure should be regulated while spot-welding.

WSM

 

Here is a photo of the piece I used for the test.

 

 

I used scrap CP titanium sheet metal, 0.050" thick and a solid CP titanium pillar about 0.375" thick. During the spot-welding process the sheet metal got about orange hot and the pillar got about yellow-orange hot. The thicker the piece (in the stack) the hotter it gets, apparently.

 

This ability to spot-weld various thicknesses of CP titanium together will greatly facilitate "boxing" the cathodes around the anode, let alone attaching tubular leads to the electrodes. This is very exciting as it allows us to fabricate higher efficiency electrodes that will fit in smaller spaces in our cells (If you can get a good spot-welder [i got mine at Harbor Freight Tools, on sale for $150]).

 

WSM