making potassium (per) chlorate

[WSM]

oh i wont be worrying about the hose getting jammed. i already know how i am going to tackle thta problem, and that is that if i am going to leave it running continuously , i am going to make sure the tip of the hose is never actually submerged in the water.

i am going to put the tube pointing down, through a fat sealed peice of pvc, and it will catch the air keeping the tube out of water. also, because the air is going from a small tube to a big pipe (figuratively) pressure will be able to build up, in there should the chlorate somehow magically block the pvc pipe section. the pressure will build up and the air will force off the crystals.

WSM, do you actually use a bubbler stone? i was considering getting a new bubbler stone anyway soon, since i need to keep my live bait alive longer when fishing (its a portable aerator) and that i could use it in the cell. but i decided not to since i thought that it would be eaten away by the chlorate cell, or do they work?

If my current plan failes, i do like to have a backup.

 

Hi OMBJ,

 

I don't use an air stone or haven't yet. It occured to me after I posted that suggestion, to use a tube blocked on the end with several tiny holes drilled through the sides for a short space, somewhat like a soaker hose for the garden. The goal was to prevent the big bubbles I saw in my little experiment (pickle jar) run last month. That setup worked but I would have been happier with smaller bubbles which wouldn't splash the salty liquor as much when they broke the surface.

 

The trick with a pickle jar setup is to not let the liquor rise above the shoulder of the jar (or below the top of the electrodes), so the liquid stays in the top space above the liquid and doesn't splash up and leave salt streaks down the outside of the jar. I prefer to keep things inside the cell from making a wet mess outside the cell.

 

I suppose your large pipe idea could work for me if I drilled tiny holes and let that act as a PVC bubble stone. In fact I like the idea; take a short length of PVC pipe, say 50mm, glue a PVC cap on either end, drill several tiny holes around it in no particular pattern then drill and tap a hole on one end to screw a compatible hose barb connection for the air tube, VIOLA!, a PVC bubble stone; genius! Thanks OMBJ

 

WSM

[WSM]

Ambient temperature this morning was only 5C, the cell has cooled to 15C. The buildup on the electrodes has been decreasing since it first started cooling. I assume because the saturated solution, is much less dense, since the cell has cooled by 20C. the weather is supposed to warm up by about 12C over the next couple of days. It will be interesting to see what happens. An insulated cell ma be needed.

 

As I see it there are two possible solutions to the temperature shift problem. 1) Insulate, as you suggest (keep the heat in), or 2) Increase the cell temperature (by an internal or external source).

 

Is it possible to move the electrodes closer to each other? If closer, they may increase the temperature the cell runs at and could keep things in solution till you're ready to cool it at shutdown and then harvest the crystals (unless the cell is saturated and the crystals dump out anyway). Another thought, is there a porous container of some sort we could use to fill with feed stock (course salt), leave it submerged in the cell and let the depleated mother liquor replenish naturally as the chlorate crystalizes out? The cell could almost run continuously with a cell set up like that (if it works, that is...).

 

WSM

[hillbillyreefer]

As I see it there are two possible solutions to the temperature shift problem. 1) Insulate, as you suggest (keep the heat in), or 2) Increase the cell temperature (by an internal or external source).

 

Is it possible to move the electrodes closer to each other? If closer, they may increase the temperature the cell runs at and could keep things in solution till you're ready to cool it at shutdown and then harvest the crystals (unless the cell is saturated and the crystals dump out anyway). Another thought, is there a porous container of some sort we could use to fill with feed stock (course salt), leave it submerged in the cell and let the depleated mother liquor replenish naturally as the chlorate crystalizes out? The cell could almost run continuously with a cell set up like that (if it works, that is...).

 

WSM

 

The electodes are only about 1/2" apart as it is. Any closer together and the crystal buildup may cause trouble.

 

When I setup the cell the kcl didn't all dissolve into the solution. I calculated the amount of kcl the cell would take, dumped it into the pail, then filled it with boiling water. It didn't all dissolve, I'd estimate close to a kg stayed on the bottom of the cell. Rather than scoop it out I just left it, and started the cell up. Most of it has now dissolved, with twice daily stirring, although the big chunks of chlorate at the bottom are making it increasingly difficult to stir. The cell temp has been reasonably constant at between 15 and 18C. For the last 48 hours or so. The electrodes had very little crystal buildup last night, and none this morning. My theory is it has come back into equilibrium, with the salts precipitating out due to cool temps. One other observation, since it has cooled the amount of bubbling around the electrodes has diminished substantially. My theory on is that with the reduced saturation point of the mother liquor the electrodes need to work harder to find friends to react with.

[patsroom]

cell ideals side mount redone.bmp

 

OMBJ

Something that might work for you is a PVC pipe with a good size diameter that is open at the bottom end only. At the top end insert a air tube and allow the pressure to build up till the extra air is expelled out of the bottom. Please look at the drawing to help understand what I am preposing

 

 

HillBillyReefer,

As WSM was saying raise the temp in your cell and keep it above crystallization of the salts. It does not matter how you do it, just get temp up where it will keep the crystalls from forming. And keep the temp from going too high for a cell melt down.

Pat

Edited September 3, 2011 by patsroom

[oldmanbeefjerky]

erm, thats what i said before.

[patsroom]

OMBJ,

I see. It is the same as I said three pages ago, sorry about repeating my self.

Edited September 3, 2011 by patsroom

[oldmanbeefjerky]

funny, i dont recall reading it three pages ago not being sarcastic though.

[WSM]

In fact I like the idea; take a short length of PVC pipe, say 50mm, glue a PVC cap on either end, drill several tiny holes around it in no particular pattern then drill and tap a hole on one end to screw a compatible hose barb connection for the air tube, VIOLA!, a PVC bubble stone; genius! Thanks OMBJ

WSM

 

Actually, this morning I simplified the idea and modified a slip-on 1/2" schedule 40 PVC pipe cap. I turned the OD on a lathe to make the sides parallel and drilled number 60 sized (about 1.1mm in diameter) holes all over it. I drilled and tapped an 1/8" NPT hole to fit a barb fitting for 1/8" air tubing plus cut a disk of grey, 1/8" thick PVC sheet to seal the open end of the pipe cap. When I assemble it with PVC glue and screw in the barb fitting, my new PVC air stone is complete.

 

 

I realize I may have to add an inert weight to keep it from floating in the cell, but it ought to work great.

 

WSM

Edited September 3, 2011 by WSM

[patsroom]

funny, i dont recall reading it three pages ago not being sarcastic though.

 

 

I am sorry about that., as I did not make it clear that it was in the drawing. I find that it helps to draw instead of writing a description sometimes.(A picture is worth a thousand words?)

But after looking at the numbers of downloads of the drawing, I see that few have even looked at them.

Pat

[pyrojig]

Actually, this morning I simplified the idea and modified a slip-on 1/2" schedule 40 PVC pipe cap. I turned the OD on a lathe to make the sides parallel and drilled number 60 sized holes all over it. I drilled and tapped an 1/8" NPT hole to fit a barb fitting for 1/8" air tubing plus cut a disk of grey, 1/8" thick PVC sheet to seal the open end of the pipe cap. When I assemble it with PVC glue and screw in the barb fitting, my new PVC air stone is complete.

 

 

I realize I may have to add an inert weight to keep it from floating in the cell, but it ought to work great.

 

WSM

 

 

 

I love your design. It is simple and looks like it will be a performer. I had one Q. about crystal density and the formation of kclo3 crystals under cell conditions( with ph control).

 

I have harvested rather dense and heavier crystals of kclo3 in this last run with MMO and TI electrodes. My past experience with graphite was decent, but a lot of work to clean the kclo3. I have harvested dense crystals before , but nothing like these. The cell temp is right around 50*c and It shows that it has some effect on the shape and size of these crystals. I have a picture of the last harvest and a comparison of one of my older graphite/Kclo3 crystals to show the diff.

Edited September 3, 2011 by pyrojig

[WSM]

I love your design. It is simple and looks like it will be a performer. I had one Q. about crystal density and the formation of kclo3 crystals under cell conditions( with ph control).

I have harvested rather dense and heavier crystals of kclo3 in this last run with MMO and TI electrodes. My past experience with graphite was decent, but a lot of work to clean the kclo3. I have harvested dense crystals before , but nothing like these. The cell temp is right around 50*c and It shows that it has some effect on the shape and size of these crystals. I have a picture of the last harvest and a comparison of one of my older graphite/Kclo3 crystals to show the diff.

 

I suspect the size of your cell is allowing larger crystals to form (you did say you're using a 5gal bucket, right?) and that may be why they're so dense. That one with graphite left in looks like a lump of coal! I imagine it's quite a bit of work dissolving, filtering and recrystallizing it to get clean chlorate.

 

Thanks for the kind words about the bubbler.

 

WSM

Edited September 3, 2011 by WSM

[oldmanbeefjerky]

I love your design. It is simple and looks like it will be a performer. I had one Q. about crystal density and the formation of kclo3 crystals under cell conditions( with ph control).

 

I have harvested rather dense and heavier crystals of kclo3 in this last run with MMO and TI electrodes. My past experience with graphite was decent, but a lot of work to clean the kclo3. I have harvested dense crystals before , but nothing like these. The cell temp is right around 50*c and It shows that it has some effect on the shape and size of these crystals. I have a picture of the last harvest and a comparison of one of my older graphite/Kclo3 crystals to show the diff.

 

My only explanation as to why the crystals are so big and dense is because they are crystallizing far slower due to the large amounts of water and the heat of the water. it will crystallize slower in a steady temperature than it will in one which is reducing (such as cooling off the cell). the slower it forms i would imagine the denser it becomes. less water would be trapped in the crystals. but i have no idea other than WSM's suggestion as to WHY they are so big.

 

I also agree though, the graphite one does look like a lump of coal! maybe you should try making sodium chlorate. at least you wont have the hastle of needing to add large amounts of water to dissolve all the chlorate! plus if you plan on discarding the mothor liquor after each run, it would be safe to use a pool water filter cartridge to get all the graphite out, it should hold up again the corrosive cell solution for a while, but being fiberglass i would imagin all sorts of problems arising later on.

[Arthur]

The photo processing industry uses air bubble agitation from rigid PVC pipe run to the bottom of the tank and bent along the bottom, with holes drilled. SO rigid PVC pipe about 1/2 in OD is available from somewhere, and it stays where you fix it.

[oldmanbeefjerky]

I wonder, how much the yeild of chlorate could be increased in a non ph controlled cell if the chlorine gas could be recycled, such as by reintroducing the escaping gas multiple times into the liquor before it is allowed to leave the cell?

I have come up with an idea that would allow the gas to pass through the cell multiple times before it is allowed to escape, and it just occurred to me, " is it worth it? "

This means of course i would not start with a neutral or acidic ph to begin with

[WSM]

My only explanation as to why the crystals are so big and dense is because they are crystallizing far slower due to the large amounts of water and the heat of the water. it will crystallize slower in a steady temperature than it will in one which is reducing (such as cooling off the cell). the slower it forms i would imagine the denser it becomes. less water would be trapped in the crystals. but i have no idea other than WSM's suggestion as to WHY they are so big.

 

I agree with OMBJ. Between us I think we're getting to why it happens. Lots of material in solution and slow crystal growth are likely at the heart of it.

 

WSM

[pyrojig]

I agree with OMBJ. Between us I think we're getting to why it happens. Lots of material in solution and slow crystal growth are likely at the heart of it.

 

WSM

 

 

That seems like a reasonable answer... Given a large volume of liquid and a steady hot solution , Im sure that it will have a impact on crystal formation . Ph is another, and Im not sure if it will cause a change on the type of crystal formed. It almost seems like a cubical/pallet/hexagonal shape.. Kind of like quarts crystals grow, in one is a seed crystal and the others grow over it in a stacked fashion. Quite amazing and beautiful crystals !!! LOL..., not like my lump of coal I saved from the graphite cell. I cant tell you how many hours of slaving over a vacuum assisted filter sys. I spent cleaning those guys ..

[WSM]

I wonder, how much the yeild of chlorate could be increased in a non ph controlled cell if the chlorine gas could be recycled, such as by reintroducing the escaping gas multiple times into the liquor before it is allowed to leave the cell?

I have come up with an idea that would allow the gas to pass through the cell multiple times before it is allowed to escape, and it just occurred to me, " is it worth it? "

This means of course i would not start with a neutral or acidic ph to begin with

 

Whether or not this would work, it makes pH control more attractive by its simplicity. By timed addition of dilute HCl according to the current demand of the cell, the most favorable conditions for efficient chlorate production are created and current efficiencies can reach or exceed 90%.

 

There are too many details undiscovered yet with your suggestion and moving the gases to accomplish it would take more energy than the alternative. I'm not saying, "Don't do it", but I do see a couple problems at the outset. If you do try this idea, please share your results. I'm not aware of any work done in that area (unless I've overlooked something).

 

Good Luck .

 

WSM

[Arthur]

Recycling the Chlorine isn't fun!

1/ Chlorine is incredibly toxic and corrosive so materials need to be suitable,

2/ The Chlorine only evolves when the solution is saturated with chlorine so why do you think that bubbling it back through will help?

 

Set up your cell and look carefully at the pH change over time at current. Then from this make an informed guess at the addition of HCl needed to keep the cell within a good pH range and the frequency of additions needed to stay within limits. This way you make small automatic additions often and do a check every day. The cost of power is NOT going to decrease so optimum current efficiency seems like a good idea.

[oldmanbeefjerky]

Recycling the Chlorine isn't fun!

1/ Chlorine is incredibly toxic and corrosive so materials need to be suitable,

2/ The Chlorine only evolves when the solution is saturated with chlorine so why do you think that bubbling it back through will help?

 

Set up your cell and look carefully at the pH change over time at current. Then from this make an informed guess at the addition of HCl needed to keep the cell within a good pH range and the frequency of additions needed to stay within limits. This way you make small automatic additions often and do a check every day. The cost of power is NOT going to decrease so optimum current efficiency seems like a good idea.

 

 

The point of recycling the chlorine is to give the chlorine every opertunity to react with the hydroxides before it leaves the cell.

I do not have the means yet to manage a constant chlorine gas output as asociated with ph control which is why i was considering the idea, but if it doesnt really help then i wont bother.

Edited September 5, 2011 by oldmanbeefjerky

[WSM]

The photo processing industry uses air bubble agitation from rigid PVC pipe run to the bottom of the tank and bent along the bottom, with holes drilled. SO rigid PVC pipe about 1/2 in OD is available from somewhere, and it stays where you fix it.

 

The nature of what we're doing requires us to be able to dissassemble and reassemble components readily. The photo processing industry isn't working with saturated solutions that will jam closed with crystals. Still the idea has merit, and is one we can adapt to our purposes if we take proper precautions to prevent foreseeable problems. Thanks for the suggestion .

 

WSM

[WSM]

The point of recycling the chlorine is to give the chlorine every opertunity to react with the hydroxides before it leaves the cell.

I do not have the means yet to manage a constant chlorine gas output as asociated with ph control which is why i was considering the idea, but if it doesnt really help then i wont bother.

 

Arthur makes a good point. If the system is saturated with chlorine and is venting the surplus, would any extra help? Any OH^- will be reacted as soon as it's formed. If I remember correctly, this happens in our cells because they're not divided cells. Everything is in there, all mixed up, and the end result is we don't have separate chlorine and hydroxides, but chlorate and hydrogen formed.

 

If we design our cell right, there is ample room to allow things to react fully and if the pH is correct we get what industry calls a bulk reaction and the highest CE possible. I take this to mean we get more chlorate faster with less energy used. Sounds like a win-win to me .

 

WSM

[pyrojig]

Here is a interesting find/LOL moment ..

 

I hooked up my electrodes backwards doing a quick test for spacing.. I have never seen this reaction where the cathode gets a oxidized layer in person, but I have to say it is quite pretty ... Happens really fast btw... 15sec. I got my lid turned around and was scratching my head for a sec, not getting why my cell was only producing 1A , and no bubbles .

[oldmanbeefjerky]

how strange......

that metal behind the cathode is clean titanium yes?

strange, titanium dioxide i would have thought is supposed to be whiter that titanium, being the whitest substance there is, or so ive heard.

was it that brown already?

[Mumbles]

http://en.wikipedia.org/wiki/Anodizing#Anodized_titanium

 

Try google in the future.

[oldmanbeefjerky]

DOOM has beffallen my cell

 

This morning i decided to turn off the cooling fan because already i was getting chlorate precipitation, more and earlier than expected, and the fan was apparently keeping the cell at slightly warmer than outside temperature, perhaps 40 Celsius. also the amperage droped by about 4A so i asumed that it was doing what it did last run, so i thought the fan was making little difference, especially since it is focused on the top of the cell mainly cooling the electrode connections, which did help actually.

 

When i arrived home from school , i was shocked

The cell was running at 20A again, so apparently the fan cooling the cell lowered the amperage.

The cell had become, and stayed so hot, that the plastic over time could slowly be stretched and buckled!

 

What i think happened was that the vent tube had become blocked, and so the gas was escaping through the leaky gaps of the cell (it is capable of leaking out all the gas slightly slower than it is generated), but pressure built up, and the heat allowed the cell to balloon up, until the top popped off, at which time it would have likely had deflated due to the weight of the electrodes.

 

 

I couldnt really care less that this has happened. My concern is that this may happen to my pvc cell, which could cost me allot of money to fix .

I am going to have to get much thicker tubing for the pvc cell, and perhaps two fans blowing on it, to both regulate tempurature below 60C which is when pvc begins to become soft and cool the electrode connections and blow away leaking chlorine gas.

 

I am certainly glad i decided not to use the bubbler