Making a Chlorate Cell

I finally get set up to try a project which I've wanted to do for a long time, making potassium chlorate by electrolysis.
Starting out with a saturated solution of KCl, we construct a small 50mL chlorate cell from a beaker, a nickel cathode and mixed metal oxide anode.
Running this cell at about an amp for three days (periodically adding chloride to the cell throughout the run time) leaves us with nearly 10g of potassium chlorate to be recovered.

[@professortrog7742]

When you stopped the process it was still running on the same voltage to get 1.05 amps of current. That is an indication that the reaction was not complete, thus partially explaining your yield.

[@ianbuilder]

i love the cardboard enclosures keep it up

[@vetitiscientia7566]

good work bro 🙂👌

[@quantumlab9130]

You could also use a lead dioxide electrode if you don’t mind a slight lead contamination in your product.

[@davemwangi05]

That is dangerous, what if the lead goes to the brain of a leader?

[@GamePro-vc2vq]

@@davemwangi05 what

[@bastianthewatermelonwatile5469]

Were you the leader of one of these projects? it seams that you have got some lead in that brain of yours.

[@anthonyrickardii6198]

Nice! Very interesting! Question can a variable transformer be use for this experiment?

[@ScrapScience]

I suppose, but you'd need to convert the output to a very smooth DC (the process only works with a DC supply), and make sure to keep within the voltage range of 3V-5V (any higher, and your electrodes will easily be ruined).

[@petermaddin5611]

Where did you source your MMO anode (in Australia possibly)?

[@ScrapScience]

I got the one in this particular video from a random seller on Ebay. My other MMO electrode is from electrodesupply.com/ (a company that seems to no longer exist). If you're looking for one, I'm afraid your best bet is to probably just keep an eye on Ebay or other places that might sell one.

[@KAYLEBHD]

I don’t think you picked the mmo anode up enough

[@samivihanto605]

How does a graphite anode and a nickel cathode work?

[@ScrapScience]

It would work perfectly fine. The only issues you might run into are corrosion of the exposed nickel and erosion of the graphite (particles of which can sometimes be very difficult to filter out, leaving your product slightly brown or gray).

[@manofmesopotamia7602]

Since KClO4 solubility is too low in comparison to NaClO4 which highly soluble in water, do you think electrolysis is a perfect method to separate KCl from NaCl by converting them into perchlorates ? 🤔

[@ScrapScience]

It might work in theory, but that’s an extremely energy intensive way of separating the two, and is never going to be a quantitative method. If you want to separate sodium and potassium, it’s likely much easier to precipitate potassium out by adding ammonium perchlorate solution. It still relies on the perchlorate solubilities, but it’s much easier than electrolysis.

[@nunyabisnass1141]

I will say that despite beimg a very interesting process because it is so engaging, its also a pain in arse with tedium, special apparatuses, and being concerned with yeild and purity of both your stsrting reagents and yeild. A double displacement reaction with CaClO isnt much better in terms of yeild, but it has far fewer steps. Ill try it out and compare the two, but that might months to acquire both the tools and motiviation.

[@ScrapScience]

Oh definitely. The process is interesting from a conceptual perspective but it's not very practical or cost-effective unless you wish to make kilogram quantities of material. However, I'm a little confused about what you mean with a double displacement reaction. Using calcium hypochlorite won't give you chlorate unless you convert the anion appropriately (heat or some other oxidation method are both options for this). You can, of course, use calcium chlorate in a double displacement reaction, but I'm not aware of calcium chlorate being commonly available.

[@nunyabisnass1141]

​​@@ScrapScience yes, sorry. It was late when I posted that so my quality wasn't where it should be. However yes I meant to at least imply using CaClO as the statting material for CaClO3, then displace it with KCl. The only advantage is that it's abundant and saves a couple days of work in my 1.5 liter cell. I'm also using graphite electrodes so that's why it takes 1-2 weeks per run because I have to keep the current lower.

[@Cristi0986]

What voltage did you use??

[@ScrapScience]

I used a constant current supply set to a little over an amp. The voltage remained between 4 and 5 volts for the whole time.

[@vetitiscientia7566]

Graphite anode also works and also gives a completely black solution after the reaction complete, by the way ...😛🙂

[@ElectroShotGROUP]

Hello. I have a question. Can I use carbon electrodes for both cathode and anode? And the current at the few first days can rise???

[@ScrapScience]

Yep! Carbon electrodes will work here, though you’ll need to filter the resulting carbon dust before crystallising your final product. I’m not sure what you’re asking about regarding the current. The current can rise for many reasons.

[@ElectroShotGROUP]

Okay I will try it, thanks for response. Your film is very good, I learned a lot of things. 👍🏻

[@rotorrant5867]

Would the electrodes out of a pool chlorinator work?

[@ScrapScience]

Yep! They're perfect for the job.

[@science0074]

And how much did the tiny mmo anode cost?

[@ScrapScience]

It was something like $10 to $15 I think, I got it pretty cheap from an eBay seller. To be fair though, I’d been checking eBay for about a year to find one for a low price like this, they don’t seem to pop up too often.

[@science0074]

Scrap Science, yeah me to i bought one for 35$ actually it was this one: www.ebay.com/itm/MMO-Anode-Ruthenium-Iridium-Oxide-RU-IR-KCLO3/202784113922?hash=item2f36e00502:g:7P0AAOSw95hdhrjc I used it around 4months at 1A around 4.5 volts but got a terrible yield of only 300gramms of KCLO3. And btw from where do you know how to do the math?

[@ScrapScience]

I used this website as a guide for all my calculations: www.chlorates.exrockets.com/chlorate.html That’s where I got all the figures for stuff like the recommended current density, minimum chloride concentration and the expected efficiency of the cell. Looking back at it now, I probably should have read the bit on cathodes which states “using nickel will leave a black mess in the chlorate cell”, whoops.

[@science0074]

Hahaha whoopsie there goes the yield. Thank you very much mate for your answers👍🏻

[@yarakexpress9116]

Where can I find those MMO electrodes ?

[@ScrapScience]

You can often find them being sold on Ebay (just search for 'MMO anode'). High quality ones are also available from electrodesupply.com/

[@mohsenium]

Thank for your informations Do you think using a pbo2 plates is effective ?!

[@ScrapScience]

It depends how it was made. - A battery PbO2 plate will fail nearly instantly, and it not a viable option. - An anodised piece of lead will fail similarly to a battery plate. - A graphite or titanium substrate with PbO2 properly plated on the surface will work to some degree, though this will depend on the quality of the plating. - A professionally made titanium substrate PbO2 anode is ideal here, and will last a long time.

[@mohsenium]

@@ScrapScience ok , thank you

[@Telectronics]

You can use graphite electrodes as your cathode as well with the mmo together as anode. I have not seen any damage to the graphite as cathode side.

[@davemwangi05]

How mash yied did you get while ushing garaphite cathode? Mine chlorate cell is dissapointing at me.

[@Telectronics]

@@davemwangi05 Starting from 350g NaCl and 2A/12V for a Month, both graphite cathode and anode after converting it with K2CO3 and two recrystilizations there was just under 100g KClO3 left. But my setup was basic as hell which is not good for a good yield. Means I had a ton of hypochlorite in there :D I bet If you stay always above 40°C right from the start use 20A/5V or higher and control If the PH is at 6,5-7 it should be better. Well If you begin with that I recommend you an automation setup with PH control and pumps that use liquid from a NaCl container and pump the NaClO3 out in a big recrystalization dish so it can crystalize out. Reuse the rest of the water to resalt it and pump it again back in the NaCl container so the cycle is closed. As a PH buffer I have read chromates which are toxic or persulfates should work well.

[@KClO3]

@@Telectronics 12v is way too much, try using 5

[@Telectronics]

@@KClO3 The problem was the amps get too low even 1cm apart. Is this because my surface of the carbon electrodes were too small ? Salt solution was saturated as well.

[@KClO3]

What kind of carbon electrodes? Where did they come from, how big are they?

[@samivihanto605]

Hi. What is a black elektrode, carbon? I understand english, very little🙂

[@ScrapScience]

The electrode is called a 'mixed metal oxide' anode. It's probably easiest to have a look at these resources if that term doesn't mean anything to you: en.wikipedia.org/wiki/Mixed_metal_oxide_electrode www.chlorates.exrockets.com/leaddiox/dsa.html

[@__djcruzer__8986]

for 2.5 liters cell running with 5.2 Amps on electrolytez...how many days it should percipitate chlorate?

[@igorpadurjan5714]

Depends on your cell temperature. Better to use a smaller cell with that amperage, like 800ml. I doubt 5.2amps are enough to heat 2.5l to 40-70°C needed for chlorate electrolysis, so your cell probably wont make any chlorate, just hypochlorite i think. You can maybe try boiling that down to turn it to chlorate but id say its not worth the effort, make a new proper cell instead. 5.2amp should keep 800ml solution reasonably hot

[@__djcruzer__8986]

@@igorpadurjan5714 i measure the heat it is only 37C

[@igorpadurjan5714]

@@__djcruzer__8986 Forgot to mention it also depends on temp outside cell, so ignore my first recommendation of 800ml. Do some experimentation. In my experience things really dont go right under 40°C. Pour off 200-600ml from your current cell and it should be ok. Time needed for precipitate is hard to calculate without already having done it once because most cells are different. You could try reading "Running time" section on chlorates.exrockets.com

[@davemwangi05]

@@igorpadurjan5714 You mene 40 diegerees can convert into chlorate? I thought 70 is the minimam.

[@oflfishingandhunting457]

Can you use carbon rods?

[@ScrapScience]

You sure can! Keep it in mind that your final product will have a bunch of carbon dust in it though (which you can filter out to some extent, but you'll always be left with some contamination).

[@Taha-hv6yj]

Can you make potassium chlorate by burning wood and then putting the residue in hydrochloric acid?

[@ScrapScience]

Not potassium chlorate, no. It might be feasible to make potassium chloride like that, and then use this process to turn it into the chlorate, but wood ash and HCl alone won't make KClO3

[@Taha-hv6yj]

@@ScrapScience oh sorry i meant potassium chloride

[@Taha-hv6yj]

@@ScrapScience thank you so much

[@Pyrokartoffel]

Ash is very unpure potassium Carbonate

[@hanleypc]

You could revisit this project but use Muriate of Potash fertiliser which is really cheap!

[@ScrapScience]

That would be ideal. However, muriate of potash fertiliser is tricky to find where I live, and I haven't found a source pure enough for a chlorate cell yet. One day I'll hopefully find some and can then build a much bigger cell.

[@science0074]

Hey mate why arent you making GSLD (Graphite Substrate lead Dioxide) anode) I actually tried it with acetates and it worked pretty good. I would love to see how to make an flat sheet anode or mesh because you have to spin the anode or get special chemicals

[@ScrapScience]

Yeah, I'd definitely like to give it a go one day. I don't think I've got the right setup for dealing with soluble lead compounds at the moment though, I try my best not to get poisoned. Hopefully that'll be a project for the future though, then I can make perchlorates too!

[@science0074]

Scrap Science haha yeah that wouldn't be very good. Can't wait for your next project

[@Coticosimo]

Perhaps if vibration from dc haptic motor is work for flat sheet anode plating

[@loquiando6824]

Can the platinum anode be replaced by a titanium anode and a stainless steel cathode? help please thanks

[@kastonmurrell6649]

I've read in a paper that stainless steel is a decent cathode if it gets removed when the electrolysis is done (though titanium was stated to be better). Titanium was stated to do poorly though and I'm thinking that's because it passivates when used as the anode. A cheaper/easier to find substitute for platinum/MMO anodes would be graphite, though it does erode faster than the other two.

[@loquiando6824]

@@kastonmurrell6649 brother is there any chance that it will generate potassium chlorate leaving the titanium anode?

[@kastonmurrell6649]

@@loquiando6824 There's probably a chance it would produce some but I think it's more likely that either anode passivation or straight up erosion would make it a poor choice.

[@loquiando6824]

@@kastonmurrell6649 Today I managed to get a mixed metal oxide titanium mesh that they use for galvanizing processes. Is it possible that it works better for me as an anode?

[@kastonmurrell6649]

@@loquiando6824 Yeah, mixed metal oxide should work. The chlorates.exrockets page has 250 mA/cm^2 as the current density and 70-80 degrees C.

[@user-lm5yo3fy1g]

can i use titanium for anode and graphite for cathode?

[@ScrapScience]

No, but you can do the exact opposite.

[@user-lm5yo3fy1g]

@@ScrapScience but if use graphite as an anode, it will dissolve with chlorine and pollute the electrolyte. Does titanium has corrosive resistance from chlorine?

[@tflowtarik8486]

Ok

[@tomspeed2000]

How much kcl for 1L water pls?

[@ScrapScience]

It depends on how much chlorate you want to make. Regardless, you should aim for a saturated solution to start off with, and add more chloride as you make chlorate until you have enough.

[@robertkeyes258]

I think that if you use compost that has more animal waste in it, you'd have more nitrogen. Of course, poop smells bad, perhaps use horse manure rather than some of the others. I don't know the relative amount of nitrogen in different manures though.

[@chemistryofquestionablequa6252]

Chicken and rabbit manure and urine in the case of rabbits have the highest.

[@amarissimus29]

I'm going to have to go ahead and disagree with you about that cathode... While you demonstrated that nickel is useable, anyone going for a productive cell will quickly realize what a monstrous pain it is to deal with degrading electrodes. Also, if someone goes to to trouble of obtaining the required MMO anode it would be pretty silly not to get a titanium cathode at the same time. Other than the nitpick, nice demo and explanation.