What Went Wrong in My Attempt to Make Potassium Chlorate?

[Letda]

I guess I’m kinda of an unusual person, I’m a psychology major with a weird fascination with astrophysiology and aeronomics, so I guess I’m not trying to make "just" fireworks for the 4th of July but I want to use concepts from these basic principles to further my know how in such matters...

So, when boiling the bleach, do you just boil until no liquid is left or do you get the crystals before that, and are they what I need in pyrotechnics? And I’m totally unfamiliar with electrolytic, is that just like putting a positive charge on one end of the cup and neg. on the other end? As you can see, at 17, I think I'm a little behind, I was too cool to take chem. serious in school... how sad huh!

 

[mrjeffy321]

The bleach boiling method is easiest to understand.
Bleach is a solution NaOCl (sodium hypochlorite), and generally it has a lot of other stuff in there too, I know that clorox bleach is 6% NaOCl, 5.63% NaCl, and .015% NaOH, and the rest it is just inert stuff and/or water. All you are concerned with right now is the NaOCl.
When you boil bleach, the NaOCl decomposes to form NaClO3 and NaCl,
3NaClO --> NaClO3 + 2NaCl
Sodium hypochlorite is very soluble in water (100 g / 100 mL), but sodium Chloride not so much by comparison. So the trick is getting the maximum possible amount of NaClO3 dissolved in the smallest amount of water possible and not have very much "other" stuff in solution, like NaCl.

This page,
http://www.wfvisser.dds.nl/EN/chlorate_EN.html#therm_starting
gives instructions on how to make chlorate both using electrolysis and thermal decomposition of hypochlorites.

You will see in those instructions that you are suppose to boil 1 L of 4% bleach down to 140 mL. If you do the math (and I have), you will find that this is a lot more than is really necesary to hold the amount of NaClO3 you will have left after decomposing the NaOCl. The reason is because there is all that other stuff in solution too. Actually, in practice, if you follow those instructions, there will be NaCl coming out of solution even before your done boiling.

Anyway, so now you have a solution of NaClO3 and some NaCl. But you wanted KClO3, not NaClO3! to turn the sodium chlorate into potassium chlorate, you can use a double replacement reaction between the NaClO3 and KCl. The potassium ion will push the Sodium out of the NaClO3 and replace it, and then the Na ion will join up with the Chlorine ion,
NaClO3 + KCl --> KClO3 + NaCl

After you do this, you should notice a white percipitate forming. This because unlike NaClO3, KClO3 is not nearly as soluble, not even close.
But to maximize yeild, we want to get all the KClO3 out that we can, so we cool the solution down to just around 0 degrees celsius, and then filter out the percipitate, which will be mostly KClO3 and some NaCl.


The Key to the whole reaction is that bleach (NaOCl) will decompose and form NaClO3, which can them be turned into KClO3.

the electrolytic method is much more complex, but is explained in the web page provided above.

 

[Letda]

I understand this a lot better than before, so thnx. But, where do you get potassium chloride, is that the salt substitute? and is the NaCLO3 worth anything in that form or must the Na be replaced with the K?

 

[mrjeffy321]

I buy my Potassium Chloride as a salt substitute, called, "NoSalt", there are also salt substitutes (I think called "LoSalt"), but these also contain a large part sodium chloride, you want to get the one with as much potassium chloride as possible.
Sodium Chlorate is in itself worth something. It will react very similar to KClO3, but because of its high solubility, it is hard to extract. a lot of the time in chemical formulas for pyrotechnic things, KClO3 and NaClO3 are interchangeable.

 

[Letda]

so let me make sure I am understanding this. When you boil the bleach, you get NaClO3 crystals after filtering the liquid, or is the liquide the NaClO3?

 

[mrjeffy321]

by boiling bleach, you make NaClO3 AND NaCl.
Since NaClO3 is so much more soluble than NaCl, most (or all) of the crystals that percipitate out will be NaCl, and the NaClO3 will remain in solution.

Then when you add KCl, you make KClO3 and NaCl. this time NaCl is much more soluble than KClO3, so most of the percipitate is KClO3 and then NaCl remains in solution.

 

[Letda]

Thnx,i just bought everything 10 mins ago so ill be testing everything tomorrow, ill let you knogw how things o. thnx for all of the help.

 

[Letda]

well, my first run was a complete and utter failure...all i got was a bunch of brown and black stuff. I filtered it out, added the KCl and recooked...same thing...and i got no noticable crystals the first time? i guess ill start round two here in a bit...any suggestions?

 

[Letda]

ok, i managed to get KCl pure crystals using the boiling process, but i don't know how the bleach is suppposed to work, i boil and all i get is a bunch of brown and balck crap. no crystals form, I am i boiling to much or not enought or what?

 

[mrjeffy321]

Are you following the instructions in the link I provided a couple posts back,
http://www.wfvisser.dds.nl/EN/chlorate_EN.html#therm_starting
I found if you follow these instructions pretty closely, you will have very good results, although some deviation can be made to see what works best.

You should boil the bleach in a pyrex / heat resistant glass container optinumy, definatly not metal.

 

[Letda]

i was using metal, it said stainless steel on the site if i remeber right. i guess ill get glass then. Ill get back to you when i use the glass.

 

[mrjeffy321]

I used to use stainless steel, and I kept getting some brown stuff in the mix while boiling. At first I thought it was a product from the reaction, although I couldn't explain what it was, and now I realize that it was most likely Iron Oxide being made when the bleach oxidized the Iron in the pan (my first clue is when it ate through the pan and I had a big hole in it).

Glass is definatly best, although you need to be more careful with it. I use a old coffee pot that can take the heat.

 

[Letda]

i just bought some glass bake-ware, hopefuly if i don't heat it up too fast it won't shatter. I mean if all else fails... I have on old coffee pot of my own so i can further follow in the steps of my mentor...lol.

you wouldn't happen to have anymore vidoes would you? I'm curiuos to see what you've been doing with 9 months supply. =)

 

[mrjeffy321]

Any more videos? how did you know about those?...o wait, I remember posting those 2 videos to show the difference in flame color of the two batches of KClO3.
I do have a few more of some interesting stuff I did with the KClO3 (ending dramatically on Febuary 18th), but they are too large to show.

Now, I mostly just use it in small (less than 50 grams) pyrotechnic things. Right now, my stock pile is a little less than 200 grams of KClO3. Hopefully I can get my electrolytic cell up and working again.

 

[redwraith94]

I was going to try the electrolytic cell myself, but after reading one of the links that you posted mrjeffy321, I decided to do the bleach method instead. I have tried the electrolytic methid before w/ Sodium chloride, and never was able to spend money for proper electrodes, so it always ended up something that I wasn't happy with. I just bought a gallon of the cheapest bleach that I could find. I'll keep you guys posted on how it goes.

 

[Letda]

well, i just wanted to let you know the glass worked wonders and i got exactly what i was looking for but...in the midst of all of my happiness, while cooling off...it shattered. i was so disappointed to say the least. Now i can't find anything anywhere to use that's glass and can go on the stove. if you know of anybrand or place to buy it i would be more than happy to hear about it.

OH, and good luck to you redwraith94, its kind of a pain in the butt, but I am sure youll have no promblems once you get going.

 

[mrjeffy321]

but...in the midst of all of my happiness, while cooling off...it shattered.

Oh no, I feel your pain.

Like I said before, I use an old [easily 15 to 20 years old] coffee pot, and as long as I treat it carefully, it works very well. Now-a-days, I don't think they make coffee pots as good as used to, a lot of the ones I see say specifically not to boil water in them, and others NOT FOR STOVETOP USE.
Supposidly, Pyrex brand glassware is good for this type of thing, but even that must be made in different "Grades" of heat resistivity because all the pyrex I see in the store has that "Not For Stovetop Use" warning on them.
there are laboratory glassware peices designed to withstand high temperature conditions, that might be a possibility.

 

[Letda]

My experiments are going to be post-poned for today at least, and probably tomorrow due to an unexpected direct assult from the flu virus...lol. but, not to worry, progress will presume soon enough and you'll know all aoubt it.

 

[redwraith94]

Normal glass is mostly SiO2 (Silicon Dioxide) with a lot of other impurities/color additives as well. Pyrex has B2O3 (Boron Oxide) as an additive.

The thing is that B2O3 expands a lot less than normal glass (SiO2 + whatever...Na...K...Ca...etc.) so the more Boron in the glass, the less it expands when heated, and the less it contracts when cooled. Since the glass moves less it produces much less internal stresses, which is why lab grade pyrex can usually be heated w/ a propane torch, or a bunsen burner w/ no problems @ all.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26237&item=7526217836&rd=1&ssPageName=WDVW

This is one that I will probably buy when I get paid since it will hold an entire gallon of bleach @ one crack. I am not sure if this can be used stove top though, I will have to check w/ the seller first, and you probably should too if you go to buy it.

 

[mrjeffy321]

You want to boil an entire gallon of bleach in one batch?
When I use the boiling method to make chlorate, I usually use 1300 mL of bleach (which is all my coffee pot will hold without overflowing when it boils), and it takes quite a bit of time to boil all the excess water away and process the remains. From when I begin to heat the bleach, until when I put the KClO3 solution into the freezer, it takes about 4 hours. Given most of the time is waiting for the liquid to boil and then cool down, but an entire gallon, WOW, someone is patient.

 

[redwraith94]

Yeah, if you think that is patient, wait till you here how I made my first batch. I actually used a pyrex glass bread pan (not lab grade) and put it in the oven until all of the water boiled off. I had to do six batches for the entire gallon.

 

[mrjeffy321]

So, Letda, have you gotten any results yet, give up, still sick?


A [long] while back in this thread, I think I mentioned something about a program thatr could calculate the run time of an electrolytic chlorate producing cell. The program I am/was referring to is here (at bottom of page),
http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/table54.html
As great as this program may be, I think it leaves a lot to be desired, so I decided to make my own.
Here is the link to a website that you can download (283 KB) my program's install file so you can test it out yourself, I assure you it is safe, there is no virus, spyware or anything bad, it is totally safe.
http://www.geocities.com/platapus453/Chlorate_Cell_Setup.zip
I would like for you all to test it out, tell me what you think of it, and possible give me some sugestions on how to improve it.
I personally think my program is wonderful just as it is, but I am looking at it through the eyes of a programmer and I marvel at some features I added that are taken for granted or expected in programs today.

***please note, since this program was written in Visual Basic .Net, it requres that your computer have the .Net framework (version 1.1) installed on your computer, which can be downloaded free from Microsoft***

 

[Cesium]

Alright, I have joined the quest to make potassium chlorate. I have decided to do the electrolysis of NaCl and then precipitation with KCl. I have a small batch precipitating now and I think it is working. Assuming I get KClO3, what ratios do you suggest for burning it with sugar? Anybody else try any cool things?

And also, How do you "manually" find out the amp-hours? I think I can only measure volts.

Thanks in advance.

 

[mrjeffy321]

I personally like the weight ratio of about 3 parts Chlorate to 1 part sugar (sucrose), or to be more precise, 2.86 KClO3 to 1 C12H22O11.
The more complete of a combustion you set it up to have, the cleaner it will be (ie. less smoke), you don't want too much/any excess sugar because when/if that starts to burn, it makes a lot more smoke and leaves a dark residue behind.
I have tried lots of "cool things" with KClO3, many of which included rocketry [notice the past tense]. Then on Feburary 18, 2005 (a date etched [or rather exploded] into my memory), I found out how dangerous the stuff could be.


Measuring the amp hours through the cell is very critical, it will determine how long you should run the cell and how much Chlorate you can expect to get. There are two basic method of measuing amp hours, either directly with a meter (an amp hour meter, which I tried and failed at building [unless someone with electrical skills wants to help ]), or indirectly through taking measurements and keeping a tally. Since I don't have a meter, I have been forced to do it the hard way, measure the current (amps) through the cell with an ammeter, then from that, I estimate an average current for that period of time, which I then can get my amp hour reading from. It is a hassel if you want to do it correctly. The more readings you can take, the more accurate you will be, and when you have to estimate, round down, not up, it is better to put too many amp hours through the cell than not enough.
I recently had an idea about using a watt hour meter as an amp hour meter substitute. Since power (watts) is equal to Volts * Current, and watt hours is power * time (time being in hours), if you divide watt hours by the average voltage through the cell, you should get amp hours. But I can't find any watt hour meters that will measure DC current in a reasonable price range.

 

[Cesium]

I have a multimeter and it only measures volts and ohms. Guess I need to buy an ammeter now.

I am guessing that the current changes by itself as more chlorate is produced. Otherwise you wouldn't have to keep on recording values. If you have a constant source of power and the cathode-anode spacing remains the same, the current wouldn't remain the same also?

 

[mrjeffy321]

Using Ohms law,
V = R*I
Volts = Resistance * Current, if you can measure volts and ohm, then you can determine the current.
However, I don't trust multimeters to measure resistance for me, ESPECIALLY through an electrolytic cell. I would recommend getting yourself an amp meter (preferable one that can meaure high currents, atleast a couple amps).
In a perfect world, the resistance through the cell would remain the same and that would make things much easier. But in reality, the resistance depends on many things, electrolyte concentrate (the solute and solvent will varry as the cell ran), temperature of the cell, temperature of the wires, ... .
The current will change all the time, atleast in my cell it does, sometimes you'll be lucky and it will stablelize for a while, but most of the time it will fluctuate (not drastically, but enough to make a difference).
What is your power source? Make sure it can handle outputting several amps of current if you don't plan on waiting a month for the cell to be finished, the higher the current, the less time you have to wait.
Side Note:
I ran my cell for the entire month of Febuary (1st through 28th, not continuous mind you), I put 653 amp hours through the cell, and I made a total of 140 grams of NaClO3, which gave me an efficeny of 28.3%, quite pathetic. I hope to hear some better results from you.

 

[Cesium]

Yes I have read extensively about your successes and failures. You sure have stuck with it though!

My power source is a battery charger for a drill. It's great because I get a constant flow going without batteries dying and whatnot. It gives 3.5 volts, no clue how many amps. I read on one of the sites that was linked here that 3-4 volts was recommeded.

What do you think about using several anodes and cathodes? Wouldn't the amperage increase by using 2 or more power sources connected to different sets of electrodes in the same cell?

Also, what color is your solution normally after you have run it for a day or so? On one unsucessful attempt it was brownish-yellow because of all the saturated chlorine and hypochlorous ion (I think). This time it was pretty much clear with particles of graphite flowing around.

Thanks again for all your help!

 

[mrjeffy321]

Yes I have read extensively about your successes and failures. You sure have stuck with it though!

I like when people appreciate my work, it makes all the log taking and number tallying worth while. I seem to have become somewhat of an expert on a certain, specialized, topics here.

The power souce is outputting just the bare minimum need for the reaction to occur,
"The supply must be a DC supply with a current capability of at least what you want to run the cell at and a voltage above 3.5 volts (more if you are making perchlorate)." - source
So technically, it would work. Keep in mind, as I said before, the more amp the better, and current is dependent on voltage (V = R*I), so assuming the resistance in the cell stays roughly the same, the higher the voltage, the higher the current. I use a computer AT power supply, I switch back and forth from using the +5V (gives me about 2.5 amps) and +12V (gives me about 8.0 amps) outputs. In this type of cell, I don't thinking having an over voltage will hurt any (until you get down to less than 10% chloride, then you'll start making per Chlorate).

Using more electrodes will increase the current since the combined surface area on the electrodes is greater. I use carbon-graphite electrodes which erode away slowly through use. It is good to have a very low current to surface area density on the annode (+) in order to slow the erosion, however the cathode (-) doesn't seem to erode at all, or atleat non-noticeable amounts. So using several annodes will help reduce the current density, but it will also help distribute the chlorine production thoughout the cell, thus increasing the amount of chlorine dissolved in solution. With less of the chlorine escaping into the atmoshere (besides making it better for you), it will dramtically increase efficency. I wouldn't recommend using multiple cathodes, I don't see the need, if you have the spare electodes, use the for extra annodes if anything (or spares for when one is used up).
Uisng more than one power source on the same cell is tricky and I don't recommend it. For one, it is easy to burn out a power supply that way (I have done it), also, it doesn't seem to help that much I find. You would only need to have one ground connection to one cathode, but then you could have multiple annodes connected to the outputs of several powers supplies, but this makes the total current harder to measure.

Since I use carbon-graphite electrodes, after a day of running it, my solution is as black as the nigh (especially if I use high current most of the say). If I filter the carbon out, then I am left with a yellowish liquid that looks and smells like bleach, because it is. I can then boil that down to decompose the hypochlorite (which I need to do the take a pH reading with my litmus paper), and then it becomes much cleater - almost transparent.

Have you or anyone else had a chance to look at my program to calculate the running times for a chlorate electrolytic cell (mentioned about 6 post back)? I am eager to get some user feedback on it to see how I can improve it.

 

[Letda]

yeah, iv been gone a while...sorry. I have to admit I've almost given up. I have been through 2 more glass "pots", and they keep shattering on me...its extremely frusturating. I'll try again in a few more days, [i have to work mornings now...:-(...so]. and If i break another glass i think I am going to try the electronic method...

 

[Cesium]

Nice work! I downloaded your program today. It's going to be really useful. There's no way I can really tell yet if it is accurate though. Once I get an ammeter, I am going to test it out. I'm going to see what my yield is and then calculate the efficiency of my cell using that.