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Author: Subject: No KClO3 formation in chlorate cell?
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[*] posted on 26-2-2021 at 15:27
No KClO3 formation in chlorate cell?


So one thing that I have been trying to do is to make potassium chlorate, and I've experimented with making small cells using graphite rod anodes (obtained from batteries) and stainless steel cathodes. It worked. It wasn't very efficient, but I did manage to get a yield of around 35 grams of KClO3 from the 100 grams or so of potassium chloride/distilled water solution. It was black due to graphite contamination, but it still worked.

I then decided to get a small MMO anode and Titanium cathode and a 1.2 liter jar just to see how much I could make. I ran the cell for about a week using around 500 grams of chloride to 600 milliliters water, and left it running at roughly 2.5 amps/3.5 volts for that time. I did have a mishap where the lid popped out due to gas pressure build up, but thankfully nothing happened and I was able to put everything back together again and continue.

It seemed like I had a decent amount of chlorate precipitate at the bottom after about 4 days. I kept it running for a few more days and when I saw no further change I decided to switch it off. I transferred the liquid to another container and the precipitate just vanished into the solution. I figured I would need to cool down the solution to get it to crystalize again as I did in previous times with graphite anodes. There was some contamination due to the corrosion of the lid, but it wasn't too bad.

But after putting it in the fridge and later freezer for several hours. Nothing happened. The liquid smelled of bleach as I expected, but nothing crystallized. When I switched off the cell, the color of the liquid was very clear and it was room temperature.

What did I do wrong? I am still fairly new to home chemistry, but I did watch just about every single video by Nurd Rage and Canadian Chemist on chlorate production and read the articles linked on this site for small chlorate cells. I didn't add any hydrochloric acid to the cell or test the pH level. Did I apply too little current?

Right now I added another 100 grams of chloride into that solution and have the cell running again at 3.5 amps and 4.5 volts.
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[*] posted on 26-2-2021 at 18:42


So I looked through the literature again. I saw that you need 2 amps per 100 milliliters. I am guessing I used too much solution and not enough current? The voltage is sadly low, I am not sure why, but I think it's because my clips a bit more corroded.
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[*] posted on 27-2-2021 at 09:53


First, you have to warm up the cell to at least 40 C, preferably 60 C to catalyze converting of hypochlorite (ClO-, swimming pool smell) to chlorate ClO3-. And adding a knifetip of orange K2Cr2O7 (toxic , so better is an alternative: sodium persulfate Na2S2O8) to control the pH. You cannot measure the pH with pH paper as even minimum amounts of ClO- bleach it.
Current can also be somewhat higher, I use 16 A with a power supply from Amazon with voltage control. You can use an old computer power supply as well.
When you are finished, heat up the contents of the cell till almost boiling to dissolve all KClO3 and let it cool down then. Then put it into the fridge or freezer to let most crystallize out and put a jar / flask of water in the fridge. Then carefully decant off the solution and rinse the crystals with the ice cold water from the fridge and let it dry then.

This document might also help:
https://pdfhost.io/v/0ygp2v~dL_Practical_guide_to_electrolys...
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[*] posted on 27-2-2021 at 10:05


Everything metalresearcher said is correct. I also ran a cell with 1.2L volume and i had 10A of current which kept it at 42C. It worked fantastic, with a tall vessel the KClO3 crystallizes up from below in a very even layer, so you can easily track progress. Also i recommend adding a tea bag of KCl to keep the concentration at maximum all the time .

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[*] posted on 27-2-2021 at 12:00


I weighed the first batch which was 150g KCl and the yield is 129g KClO3, which means an efficiency of just over 50%. Theoretically, 150 * 122.5/74.5 = 246g KClO3 would be formed.

Now I am running a batch of 'diet salt' which I did successfully a few years ago. Diet salt is 2 parts KCl and 1 part NaCl. It has to be filtered out before electrolyzing because it contains 0.5% 'anti-coagulant' MgCO3 which makes the solution cloudy. Making use of the much worse solubility of KClO3 vs. NaClO3, the Na ions can easily be filtered out.

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[*] posted on 27-2-2021 at 12:26


Quote: Originally posted by metalresearcher  
And adding a knifetip of orange K2Cr2O7 (toxic , so better is an alternative: sodium persulfate Na2S2O8) to control the pH.


The chromate or dichromate is not to control pH, but to minimise the side reaction that converts of your hard earned hypochlorite back to chloride at the cathode.
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[*] posted on 27-2-2021 at 12:37


Thank you very much for this information. It seems like my power supply was adequate for the smaller cells I built in the past, but not for my 1.3 liter capacity cell. I ramped up the current as high as I can get it. I will need to get another power supply to go higher.

Temperature is also something else. I initially put it in an icebath, and the temperature was room temp for the rest of the time. Now after putting the electrodes deeper into the solution I did get more heat throughout the cell, but I don't know how warm it is. I don't think it's 60C, which is probably going to be a problem.


Quote:

Now I am running a batch of 'diet salt' which I did successfully a few years ago. Diet salt is 2 parts KCl and 1 part NaCl. It has to be filtered out before electrolyzing because it contains 0.5% 'anti-coagulant' MgCO3 which makes the solution cloudy. Making use of the much worse solubility of KClO3 vs. NaClO3, the Na ions can easily be filtered out.


I used salt substitute. I filtered out the potassium chloride from the other stuff and got a relatively pure product. When I started out my current cell I didn't fully dry my potassium chloride before putting it in. But after restarting my cell, I added around 100 grams of very dry potassium chloride to the solution (but did not heat it) and left a fairly saturated solution before restarting my electrolysis at the highest settings.

Thanks for the PDF. I'll be sure to look into it.


[Edited on 27-2-2021 by ManyInterests]
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[*] posted on 17-5-2022 at 21:14


I've decided to resurrect this thread.

Right now I'm returning to chlorate production. But not potassium chlorate. I am trying to make sodium chlorate. I watched a few of the videos but I was too hasty in my setup and probably should have done more research (as I will do now).

But I am going to report on what I've done... and appear to have the same issues as with potassium chlorate. I need to mention that I concluded my potassium chlorate runs with one run where I got 75 grams of very pure potassium chlorate at the cost of around 350 grams of potassium chloride.

I started my sodium chlorate run 6 days ago. I used a makeshift setup with a cheap french coffee press as a beaker (it is borosilicate glass, so it'll stand up to the heat) and I put a lid from a plastic tupperware over it, as the run I had with the metal lids caused the metal to corrode and get into my chlorates, which resulted in a contaminated producted.

I ran it at around 5.5 volts (it went up to 6.4 for a while) at 4.4 amps for 6 days. The beaker became hot to the touch, but not unbearable. I made my setup outside on my balcony and covered my everything in a large clear plastic box to protect it from rain and any elements. It was 100% sealed so any chlorine/hydrogen gasses generated can escape easily.

My starting reagents were 800ml of distilled water to 205 grams of pickling salt (pure sodium chloride with no iodine or other agents). I did not add anything else to the mix. So far I just halted the run and will let the stuff cool down. The liquid is still clear and I hope some chlorate will precipitate as it cools down. There was some chlorate production creeping up on the anode and cathode. I scraped them off and tried to light them with sugar, but I added too much sugar. They did burn slightly but no real major burn reaction (too much sugar?)

I will boil down the liquid tomorrow and I hope I will end up with some sodium chlorate. Next time I will add some HCl or sulfuric acid to the solution and make a super saturated solution of sodium chloride and do some reading on chlorate production to review.

I have a feeling I might need a new power supply. I've seen some inexpensive ones that deliver 20 amps at 5V max. the power supply I bought originally and am using can only got up to 5 amps in the best of times.

[Edited on 18-5-2022 by ManyInterests]
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[*] posted on 18-5-2022 at 01:47


At 100 percent efficiency you can expect about 0.36 g of chlorate per amp hour.
Let's say you averaged 5 amps of current.
You ran your cell for about 144 h.
So you put about 720 Ah into your cell.
You can assume about 50% efficiency.
So you will be unlikely to have produced more than about 130 g of chlorate, meaning you will need to boil your solution down to less than 100 ml to get much chlorate at all. At this point you will also be precipitating a lot of chloride as well.
The salt creep you are experiencing will likely be mostly chloride.
With all of this in mind it may be worth running your cell a little longer.
If you really want to know if the cell is definitely working, you could boil the solution down to 100 ml and hot filter it to remove the chloride, then chill the solution down as cold as you can and pour the solution off. Retain the liquid as a feed for future runs. Dry the precipitate which will be chlorate with significant chloride contamination, but suitable for testing as an oxidiser.
You could also try taking off say 50 ml of your electrolyte before you boil it down and add some potassium chloride to precipitate potassium chlorate. Assuming you add an excess of potassium chloride you can calculate the chlorate concentration in the electrolyte based on the mass of potassium chlorate that you obtain at a given temperature.
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[*] posted on 18-5-2022 at 05:44


Thanks for the advice. It sounds good. I think what I will do is restart the run (I haven't done anything to the liquid yet) until I get a new power supply. I think it might be better to invest in this thing:

https://www.amazon.ca/gp/product/B07KC55TJF/ref=ox_sc_act_ti...

This should make chlorate/perchlorate production much quicker and easier, and it is cheap, too. The only problem is obviously I will need to splice a power cable to fit it in correctly, but I got lots of spares... and a multimeter so it shouldn't be hard.

My current setup uses a laptop power supply and DROK regulator. I will be using my DROK with this only to make sure that the voltage is around 5v to start (the power supply output can be adjusted) and then let it go full blast with the cell.

The only thing with my cell is that some of the liquid did evaporate off, I will need to lower the anodes/cathodes deeper in to make sure they are fully submerged. I got nothing to lose by letting it run more.

On another note. I don't see any chlorate precipitating. But that's because of the much higher solubility of sodium in water?
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[*] posted on 18-5-2022 at 09:11


You can find that same PSU on eBay in kits if you search for PbO2 or MMO electrodes so I assume it's good.
I even saw 5v 10/20 amps PSU's like this one with an attached module for display and knobs to regulate. I dont know if it was made by the seller but that kind of PSU is what I'd get.

You could also do it yourself but considering the time / materials / learning needed I'd happily pay a few extra bucks. As you said, the PSU itself is quite cheap.




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[*] posted on 18-5-2022 at 09:31


I remember seeing one of those kits on ebay.ca (the Canadian one since I live in Canada) but I cannot find it anymore. I do still see quite a good amount of MMO anodes and Cathodes, some quite larger than the ones I have (I have an MMO anode and a titanium cathode, a 2 x 3 mesh). while having the full on kit would have been easier. at this point I feel I need a more powerful power supply and/or larger anodes/cathodes (which I will use alongside the smaller ones. I have seen people use enter sets of anodes and cathodes in unison).

But if I am going to buy another set, it will be the PbO2 anode for perchlorate production. I'm not quite at the point where I want to shell out the cash just yet. I want to try to make a good amount of sodium chlorate and convert it to perchlorate (so I can use that to make ammonium perchlorate).

I didn't that that much notes on my chlorate production in the past. This time I will. I only know I sorta stopped with the potassium chlorate when I got one good run and figured 'this is enough for now' and moved onto other experiments.
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[*] posted on 18-5-2022 at 10:57


Quote: Originally posted by ManyInterests  


On another note. I don't see any chlorate precipitating. But that's because of the much higher solubility of sodium in water?


Yes, have a look at this link
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[*] posted on 19-5-2022 at 04:54


i dont quite buy into the minimum amperage theory- maybe its amperage per volume? mind you the side facing the cathode is mostly active, so you cant truly consider both sides to be equally active- i got an MMO anode where mostly the facing side is wrecked

i managed to produce perchlorate with a 12V1A PSU and the anode was maybe 30x50mm platinized titanium
the increasing amount of ClO should cause it to naturally break down so temperature isnt the deciding factor- but its ideal to have it decently warm to promote breakdown
running UV-C light on the cell should also help promote this- but might invite the risk of having Cl2+H2 go off
persulfate, pH control and even buffers such as CaCl2/MgCl2 have been advised to boost yields

on a sidenote i have about 6 large titanium electrodes for sale, "electroplating chems" under reagents and acquisition- in case anyone needs titanium




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[*] posted on 20-5-2022 at 01:53


Quote: Originally posted by Antiswat  
i dont quite buy into the minimum amperage theory

It's hardly a "theory".
Current is a measure of the number of electrons per second and what you are doing is essentially removing electrons from Chlorine.
The more of that you do the more chlorate you make.

The minimum current is zero; how good would the yield be?
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[*] posted on 20-5-2022 at 05:38


sure sure- but ive heard it a couple of times that you need a minimum amount of amps to make any kind of electrolytic progress
i believe the actually limiting factor would be voltage, usually 3.3v is considered the minimum and usually people just go with 5v- but this also depends on concentration, temperature and electrode distancing
im just saying ive successfully made perchlorate in enough quantity to confirm its presence by methylene blue using just 1A- i dont believe you addressed this but rather implied that amps define efficiency- true.




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Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
http://www.trimen.pl/witek/calculators/stezenia.html
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[*] posted on 20-5-2022 at 16:33


OK so an update. I just got my brand new power supply and I hooked it up. You know the old joke of people having a million adapters and power cables lying around 'just in case'? Well this was one of those just in case scenarios, so I pull one out, spliced some cables, and looked up what the colors meant for a 3-pronged US power cable (green is neutral, white is live, and black is ground) and I wired it up. I tested it on my DROK and the voltage was a good 5.36. I then topped my liquid with 100 additional grams of sodium chloride and 200 ml of hot distilled water. The overall solution was mildly saturated after a bit of stirring, but I hope it will all turn into sodium chlorate in the next week.

I turned on the power but do not my DROK on since my DROK cannot handle the amperage produced by the new power supply. So I don't know if it is delivering a full 20 amps. I'm going to assume a highly conservative 15 amps just to be on the safe side. Maybe next time I will get a DROK that can handle that much so I can know how much power is being put in.

At the current moment it is running with a lot of very nice white forthing at the top. I hope to get a nice crop of chlorates in the next week.

Quote:
sure sure- but ive heard it a couple of times that you need a minimum amount of amps to make any kind of electrolytic progress
i believe the actually limiting factor would be voltage, usually 3.3v is considered the minimum and usually people just go with 5v- but this also depends on concentration, temperature and electrode distancing
im just saying ive successfully made perchlorate in enough quantity to confirm its presence by methylene blue using just 1A- i dont believe you addressed this but rather implied that amps define efficiency- true.


I did manage to make potassium chlorate with just 1A as well, but that was with graphite rods (salvaged from carbon-zinc batteries) and stainless steel for a cathode I got from a dollar store. I really liked the bric-a-brac setup, but I got around a 30% yield.

I guess you are right. But I also want a touch more efficiency and speed. The more current, the more you make, the faster it is. With my new power supply a 2 week run should be good in 3 or 4 days.

[Edited on 21-5-2022 by ManyInterests]
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[*] posted on 21-5-2022 at 07:00


the easiest method imo is to just add in an excess of NaCl, as the chlorate forms and comes out of solution it will pull in more NaCl to be converted into NaClO
but you wanna break it up every now and then- then you will indeed get NaClO3 crystals forming in there, they can get quite hard

for a quick boost in efficiency you can add in some chromium hydroxide, made from HCl+316 stainless steel or more pure chromium alloy ppt'd with Na2CO3. the Cr(OH)3 with bleach converts into bright yellow NaCrO4 which ends up at cathode preventing chlorate in solution breaking down
the iron and nickel shouldnt be much of a problem to add into the cell




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
http://www.trimen.pl/witek/calculators/stezenia.html
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[*] posted on 21-5-2022 at 07:18


Quote:
the easiest method imo is to just add in an excess of NaCl, as the chlorate forms and comes out of solution it will pull in more NaCl to be converted into NaClO
but you wanna break it up every now and then- then you will indeed get NaClO3 crystals forming in there, they can get quite hard


Yeah I added too little sodium chloride to begin with, hence why I did not see any chlorate formation. After seeing the charts for the solubility of sodium chlorate vs. potassium chlorate I realized just how much more soluble sodium is in water. I will probably need to boil down the stuff once the run is over with in order to get some out of there. I will make sure my next run will have plenty of excess chloride in solution.

For the chromium hydroxide. I have plenty of nichrome wire that I used to make electric matches with. Would that work to make chromium hydroxide? How much wire do I put in how much hydrochloric acid? Do I put in the resulting solution directly into my starting liquid or do I need to do any other processing?

Also what was ppt'd mean? As in "more pure chromium alloy ppt'd with Na2CO3"

https://bit.ly/3wFPVxE

Would this be preferable over nichrome wire or finding 316 grade steel?
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[*] posted on 23-5-2022 at 18:48


OK now almost 80 hours after I restarted, I probably ran as much of this run as I can. I will still leave it until tomorrow to give it a full 4 day (96 hour) run in addition to the time I spent previously on it. So the total time it would be running in amp hours is approximately 2,265.6 amp hours. At 50% efficiency I should have generated 407.8 grams of chlorate from the starting chlorate run of 300 grams of sodium chloride (200 to start, 100 added on the 20th). I hope I will have a good amount now.

I will be doing a second run after this is finished. I will need to boil it down and hot filter as I was recommended to do it. I hope to get a good crop of chlorate.

[Edited on 24-5-2022 by ManyInterests]
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[*] posted on 24-5-2022 at 02:11


@manyinterests
you simply take the metal chloride solution and mix with Na2CO3 until it stops bubbling
filter this, add the sludge to your cell and it should eventually turn into a bright yellow
avoid drinking this solution as its now an extra bit toxic

when boiling out the chlorate you wanna crank it up to high heat, then you simply pour the liquid off, reference solubility curve on solubility table of NaCl vs NaClO3- or just precipitate it as KClO3




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
http://www.trimen.pl/witek/calculators/stezenia.html
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[*] posted on 26-5-2022 at 04:05




If you want simplicity avoid additives of any sore. Chromates etc etc etc. There are a pile of suggestions in the literatyure.

Use a small cathode instead.
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