making potassium (per) chlorate

[WSM]

I'm planning to use a 1" x 5" anode with two titanium cathodes starting at approximately 18 amps and run until the current drops to about 9 amps.

I really like the looks of your threaded electrodes, however I'm planning to cast/ machine small aluminum blocks into which I can drill and tap two holes for bolts. The bolts will be used to fix the unit on the titanium tubing and to squish the copper wire in the electrode to the wire from the power supply- hopefully resulting in extremely low resistance.

I do have 3/8" and 1/2" tubing on hand as well which I'm hoping to save for my eventual scale-up to a larger chlorate cell and hopefully someday a perchlorate cell.

Kevin

 

Sounds excellent, Kevin. Take some photos of your setup as it comes together and later while it's running, and post them here. We'd love to see that.

 

WSM

[WSM]

Monday, I shut down the sodium chlorate experiment for maintenance and recharging. I drained the cell through a bucket filter into a couple 5 gallon buckets.

 

I've noticed some dark flakes coming out with the electrolyte as I've drained some for harvesting. I didn't know what it was, but when I inspected the electrodes (after running over 1000 hours), I saw some flaking on the cathode plates facing the anode which resembles the flakes I see in the bottom of the cell. I'm not certain but it may be titanium hydride. I need to try to collect some of the dark flakes and see if I can analyze them to be sure.

 

I'll also see if an HCl wash will remove the scale (It can't hurt).

 

Part of the reason I shut the system down is also I was seeing diminished current demand (from as high as 53 Amps, it dropped down to the lower-mid 30 Amp ranges). A friend I'm collaborating with suggested it was time to shut it down and restart, possibly because the chloride levels were getting low. I'm not sure but we'll see after I get it running again, probably this weekend.

 

I intend to continue harvesting the chlorate and replenish the electrolyte with sodium chloride before it goes back to work in the cell.

 

WSM

Edited July 14, 2016 by WSM

[WSM]

Considering the time I have left before the PGI Convention (Yes, I'm going), I'm thinking I'll take my time cleaning up and adjusting the sodium chlorate experimental system. If I start it up soon, I'll be gone for a week in the middle of the run, and the thing could run amok in my absence, without anyone watching it or able to know how to handle it and how to properly shut it down (definitely NOT a good idea) !!!

 

In the time I have before I leave, I'll continue to harvest the chlorate without boiling the electrolyte. This is because I don't want to destroy the hypochlorite and hypochlorous ions, but keep them for the next run of the system. Also I'm not worried about the (presumably) large amounts of dissolved chlorate left in the liquor, because it'll be harvested later when the next batch will concentrate the chlorate solution, and the chlorate already there will add to the process.

 

I'm considering purifying another bag of the water softener salt for the next few runs, so I'll have a fresh, new batch of purified brine to use (besides the replenished electrolyte I'll start the next batch with). I've also wondered about trying to purify the potassium chloride water softener salt chunks. I noticed some rusty metal scale in some of them, too; and it makes me think I should see if I can purify it, similar to the sodium chloride brine preparation steps I took before the sodium chlorate cell was run. It might be interesting to see the results, if I do attempt to purify my KCl. We'll see...

 

To be continued...

 

WSM

Edited July 14, 2016 by WSM

[WSM]

I do have 3/8" and 1/2" tubing on hand as well which I'm hoping to save for my eventual scale-up to a larger chlorate cell and hopefully someday a perchlorate cell.

 

What is the wall thickness of those two tubing sizes? I have some as well, but unfortunately I have more of the thin wall 1/2" than the thick wall.

 

WSM

[WSM]

I'm planning to use a 1" x 5" anode with two titanium cathodes starting at approximately 18 amps and run until the current drops to about 9 amps.

That ought to work. Let us know how it goes.

 

WSM

[WSM]

I really like the looks of your threaded electrodes, however I'm planning to cast/ machine small aluminum blocks into which I can drill and tap two holes for bolts. The bolts will be used to fix the unit on the titanium tubing and to squish the copper wire in the electrode to the wire from the power supply- hopefully resulting in extremely low resistance.

----------------------------------------

I like this idea, plus it'll require less time to prepare than the methods I'm using. I'd like to see a photo or drawing of your design.

I recommend machining solid blocks rather than cast aluminum. I think it'll work better (cast aluminum doesn't have the structural integrity that drawn or extruded aluminum does).

 

This idea looks like a hybrid between what Swede and I have done for connecting electric power to the electrode leads, but Swede's and your idea seems more versatile (adaptable for many different sizes of cable and connectors).

WSM

Edited July 15, 2016 by WSM

[WSM]

I'm continuing to harvest sodium chlorate from the mass of electrolyte drained from the cell.

 

I was thinking that some chlorate crystals would drop out in the 5 gallon buckets I'm storing the electrolyte in (at ambient temperature), but I see none. It's only when I pull out a gallon (one jar full) and put it in the refrigerator at between 0^o-5^oC, that I see crystals of chlorate drop out. They form slowly over the two or three days I leave it at the cooler temperatures.

 

I wonder if the crystals would continue to form if I leave them at about 0^oC or will the crystallization stop at some point. I'm leaning toward the crystallization reaching equilibrium and the process stopping. I don't know; I may have to leave one for a longer time and see...

 

WSM

Edited July 15, 2016 by WSM

[dagabu]

Only one way to find out.

[Arthur]

If you want to harvest ALL the chlorate you need to add KCl and ppt out as K Chlorate, -for which there are uses for smokes and some colours. BUT for this you mustn't have added extra chloride, or the surplus NaCl will drop out, giving you a mix of crystals for which we have NO use.

 

To get crystaline NaChlorate then you can only extract the difference between the cell temperature content and the fridge temperature content, but as long as the ingredients are pure enough you should be able to take some chlorate out for each electrolysis cycle.

[Arthur]

Is there any issue with running large electrodes with small currents?

[WSM]

Is there any issue with running large electrodes with small currents?

 

If run in CC (constant current) mode, no.

 

An unregulated or uncontrolled power supply (like a modified computer PS) might burn itself out trying to keep up with the current demand of large electrodes.

 

WSM

Edited July 16, 2016 by WSM

[WSM]

If you want to harvest ALL the chlorate you need to add KCl and ppt out as K Chlorate, -for which there are uses for smokes and some colours. BUT for this you mustn't have added extra chloride, or the surplus NaCl will drop out, giving you a mix of crystals for which we have NO use.

To get crystaline NaChlorate then you can only extract the difference between the cell temperature content and the fridge temperature content, but as long as the ingredients are pure enough you should be able to take some chlorate out for each electrolysis cycle.

 

I don't want all the chlorate out. I want whatever will drop out by refrigerating the electrolyte. I know that whatever chlorate is left over after harvesting isn't wasted, but will be harvested in later runs after recharging the depleted liquor with purified sodium chloride.

 

If I want potassium chlorate, I'll electrolyze potassium chloride solution. I can't see wasting my hard won sodium chlorate on making potassium chlorate when it's nearly trivial to make it directly from KCl.

 

My idea is to use the sodium chlorate as feedstock for making sodium perchlorate (for conversion to potassium perchlorate) or specialty chlorates (such as barium chlorate). The main reason I started on the quest to make sodium chlorate is because I exhausted my meager supply making sodium perchlorate about a year ago (plus the current high cost of commercial sodium chlorate is a real motivation).

 

WSM

[memo]

are you going to do a test run on making sodium perchlorate ? I would like to see how it turns out.

 

memo

[WSM]

Only one way to find out.

 

Okay, so I will .

 

WSM

[WSM]

are you going to do a test run on making sodium perchlorate? I would like to see how it turns out.

memo

 

Actually, I did.

 

It was about June, 2015, when I was running sodium perchlorate cells (2) using platinized titanium and PbO₂ as anodes in two different cells, one at a time. I was able to make sodium perchlorate solution, which I purified (destroyed residual chlorate) and then converted samples of it into potassium perchlorate with KCl solution.

 

It worked very well, but alas, I quickly ran out of sodium chlorate (hence my efforts since then to make my own since the cost of sodium chlorate is too high). If you look at my posts from about April to June last year, you should be able to follow what I was doing.

 

When I'm able to make up a large supply of sodium chlorate, I intend to resume my perchlorate experiments .

 

WSM

Edited July 16, 2016 by WSM

[TomasBrod]

I don't want all the chlorate out. I want whatever will drop out by refrigerating the electrolyte. I know that whatever chlorate is left over after harvesting isn't wasted, but will be harvested in later runs after recharging the depleted liquor with purified sodium chloride.

 

This is the state of mind one must reach to manufacture sodium chlorate efficiently.

Congratulations on the first run of this large cell. Please post pictures of the harvest before you leave

[WSM]

This is the state of mind one must reach to manufacture sodium chlorate efficiently.

Congratulations on the first run of this large cell. Please post pictures of the harvest before you leave

 

I think so, too.

 

I can't imagine going to all the trouble and time to make a large batch of electrolyte, full of precursors and dissolved chlorate, just to destroy it and start all over again. That is false economy. Better to collect what NaClO₃ you can, recharge the electrolyte and run some more; improving your yield as you go by concentrating the chlorates in the electrolyte.

 

I think the yield will naturally improve with subsequent runs, even without pH control; but even better with pH control, which I intend to do after the next run. My plan is:

• do an initial run w/o pH control (build precursors and establish the NaClO₃ cell) (done!)
• do a second run with recharged electrolyte, w/o pH control, to see (record) the difference
• do a third run with recharged electrolyte, add the pH control and see (record) the difference
• continue thereafter, fine tuning the system as I go

The ultimate goal is to build a good stock of sodium chlorate to feed my sodium perchlorate experiments and also to experiment with making specialty chlorates. If the specialty chlorates don't work out, making useful perchlorates is an excellent use for all the NaClO₃ produced.

 

Thank you. I have some photos of the crystals harvested so far, but I haven't processed half the electrolyte yet. I'll have some nice pictures to show later.

 

WSM

Edited July 16, 2016 by WSM

[Arthur]

Electrolysis will have created lots of chlorate which remains soluble at 5C so this will always be there and chloride added and electrolysed should be 100% turned to chlorate that can be precipitated out.

[pyrojig]

http://i918.photobucket.com/albums/ad24/pyrojig/Chlorate%20Designs%20and%20related%20materials/SNC01235.jpgHere is the pic of the kclo3 crystals you where interested in WSM:

[WSM]

Here is the pic of the kclo3 crystals you where interested in WSM:

 

Nice! Thanks, pyrojig. What size are they?

 

WSM

Edited July 16, 2016 by WSM

[pyrojig]

It is a old picture , I really cant give a accurate size . I would say they averaged on the large side( about 1/2" wide by 1" long)

and normally about a 1/4" wide x 1/2-3/4" long. They had a distinct quarts like shape and seemed to layer platelets as they formed.

[WSM]

So far, I've dried several batches (from one gallon [3.785 liter] jars of electrolyte in the fridge) of NaClO₃ crystals and the total weight is ~1.5 Kilos (over 3 lbs):

 

 

Several more jars full of saturated electrolyte are in the fridge and will drop out as much sodium chlorate as possible at 0^oC over three days time:

 

 

At this rate, I anticipate all the electrolyte (about 27 liters [~7 gallons]) will be processed within a week. I've reserved one jar to stay in the fridge for MUCH longer to test whether the crystals will continue to grow or if they'll reach equilibrium at some point.

 

This is going well, but I plan to continue my exploration of the sodium system till it's much more complete. I'm just beginning my research, but it's getting more exciting as time goes on... and there's a lot more to learn.

 

WSM

Edited July 18, 2016 by WSM

[Kevin]

I like this idea, plus it'll require less time to prepare than the methods I'm using. I'd like to see a photo or drawing of your design.

 

I recommend machining solid blocks rather than cast aluminum. I think it'll work better (cast aluminum doesn't have the structural integrity that drawn or extruded aluminum does).

 

This idea looks like a hybrid between what Swede and I have done for connecting electric power to the electrode leads, but Swede's and your idea seems more versatile (adaptable for many different sizes of cable and connectors).

 

WSM

 

I should have elaborated.. My plan is to cast a couple aluminum blocks into which I'll drill the required holes for the wires/ mounting bolts. The best picture I currently have is of the pieces that I cast for my spot welder. I drilled/ tapped the aluminum to thread the copper tips into it and then the copper wires are pressed against the tips by the bolts entering in from the top and bottom respectively. (The wires have since been upgraded to 00 gauge)

I'm currently working on figuring out my lid (particularly how to seal it) and my acid delivery system. I have some plastic and rubber kicking around of unknown types which I hope to be able to use- a few samples have been soaking in full strength muriatic acid for about a week to see how they hold up. I also salvaged a solenoid valve from an old dishwasher; I looked it up a while ago and I think its body is polypropylene, but I couldn't find the datasheets for it again to verify that. I'll test the solenoid valve with diluted HCl when I have the free time for it.

Kevin

Edited July 19, 2016 by Kevin

[WSM]

I should have elaborated.. My plan is to cast a couple aluminum blocks into which I'll drill the required holes for the wires/ mounting bolts. The best picture I currently have is of the pieces that I cast for my spot welder. I drilled/ tapped the aluminum to thread the copper tips into it and then the copper wires are pressed against the tips by the bolts entering in from the top and bottom respectively. (The wires have since been upgraded to 00 gauge)

I'm currently working on figuring out my lid (particularly how to seal it) and my acid delivery system. I have some plastic and rubber kicking around of unknown types which I hope to be able to use- a few samples have been soaking in full strength muriatic acid for about a week to see how they hold up. I also salvaged a solenoid valve from an old dishwasher; I looked it up a while ago and I think its body is polypropylene, but I couldn't find the datasheets for it again to verify that. I'll test the solenoid valve with diluted HCl when I have the free time for it.

Kevin

 

Hi Kevin,

 

Nice job on the spot welder.

 

HCl might not be the best test for plastics (polymers) or rubber (elastomers) for use in the cell. The electrolyte is more hot bleach (hypochlorite), than acid. My research has shown that PVC will hold up better than PP (polypropylene). Polyethylene seems to be better suited as well, but PVC or CPVC are better.

 

For compatibility of materials, several polymer and elastomer sellers have compatibility charts which list various materials and their product compatibility with those materials.

 

Check my blogs (Homegrown Oxidizers) for ideas as to how you might want to seal your cell lid. There's a photo of the silicone seal I am using on home made PVC cell lids. There are many ways to solve a problem, and some work better than others.

 

WSM

[WSM]

A few days ago I found a few small square crystals on the bottom of one of the buckets I'm storing saturated cell liquor in. I did a small flame test on a few and I believe they're NaClO₃. They crystallized at room temperature, which I think is significant.

 

WSM