making potassium (per) chlorate

[WSM]

Glass filters of this size are not all that common, and hardly an affordable item. It looks like $3-5 per sheet! It looks like the common sizes top out around 15cm.

 

That's unfortunate. Glass fiber filters for use in a large (benchtop) Buchner funnel would be very useful.

 

WSM

[WSM]

OK If needed what about the finest glass tissue sometimes used in fine finish GRP layup, or maybe just a Buchner funnel with no paper -ideal for bigger crystals.

 

I always use filter paper in my Buchner funnels. I'm not familiar with the "glass tissue" you're describing; what is it?

 

I like the method pyrojig uses for separation of solid materials using a bucket filter (as Duda Diesel sells) in a common 5 gallon HDPE bucket. There are places in my current experiments where his method works well to separate contaminants from my precious mother liquor.

 

WSM

Edited July 22, 2016 by WSM

[taiwanluthiers]

What about using standard fiberglass cloth as "filter"? You know the kind used for doing auto body work, boats, etc.?

[WSM]

What about using standard fiberglass cloth as "filter"? You know the kind used for doing auto body work, boats, etc.?

I don't think the loose weave of glass fibers usually used, would work.

 

WSM

Edited July 22, 2016 by WSM

[pyrojig]

I second the duda diesel filters !!!! They are a cheap and very effective way to harvest large amounts of crystals . I was pushing the limits with 5-7 # of wet crystals on the screen of kclo3 and they held like a champ !!! I think that the simple and least expensive method wins the cake on filtering the batches ( mostly when it comes to large production on a amateur scale/ )

 

Btw the idea was developed from Swede on the duda diesel screens if im not mistaken . I cant take credit for such a great find. But love the convenience of them .

[taiwanluthiers]

Those crystals are big enough that it doesn't require a very tight weave to filter them out. Any lightweight satin cloth should be sufficient. In fact there are fiberglass mat (that is cheaper than cloth) that will work very well for this.

[WSM]

Those crystals are big enough that it doesn't require a very tight weave to filter them out. Any lightweight satin cloth should be sufficient. In fact there are fiberglass mat (that is cheaper than cloth) that will work very well for this.

It may work just fine, for a while. Since so many things are negatively affected by the liquor (a potent bleach, actually), I've proceeded with the understanding that my filters are temporary in nature (disposable) so I plan to burn them when they're dry and saturated with fine chlorate.

 

If I were more thrifty, I suppose a soak in distilled water would allow me to recover the small portion of sodium chlorate I'm disposing of by burning the dry filter papers and paper towels.

 

WSM

Edited July 22, 2016 by WSM

[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

 

 

The hydrochloric acid testing was for my acid dosing system; everything thus far looks good enough to use with an actual cell. However, I've read in numerous places that chlorine gas is formed when the acid is added, so I'm trying to figure out how to divert that as I don't think my acid system will be well suited for chlorine. The best idea I have come up with is to use CPVC tubing to pass through the lid, the line will then bend past 90 degrees (probably closer to 180 degrees) to trap gases. The line will then bend back upwards and connect to a solenoid valve. Overall, the acid system will resemble a capital letter 'N'. My thoughts are that once the system has settled out, there will be chlorine gas in the line that neither grows or shrinks (significantly). Any thoughts?

I'm also going to try to make my own pinch valve to use instead of a needle valve. A few tests will show if it's consistant enough.

I think I've read through your blogs a year or more ago- but thanks for the reminder: re-reading them has provided valuable insights and reminders! Do you know how well flexible PVC tubing would hold up as a sealing material? I have a slightly different sealing method in mind and I'm wondering if some tubing cut into a narrow strip would last.

Kevin

[WSM]

If you are developing crystals of any size, I'd go for a 600mesh (or near) stainless steel sieve. without any paper. Whatever paper you have used will be the equivalent of super fast touch paper as soon as it dries.

Alternatively look for Whatman GF-A or GF-B filter circles. Work well flat in a Buchner funnel and as they are made from glass fibres there is little chance of a chlorate accelerated fire.

 

I burned a few of the chlorate impregnated paper towels tonight (one or two at a time) in my barbeque. I'd say they burn less like touch paper and more like flash paper.

 

 

The last one (after the video clip) was more like flash! Amazing stuff. I have a new found respect for it !!!

 

WSM

[WSM]

The hydrochloric acid testing was for my acid dosing system; everything thus far looks good enough to use with an actual cell. However, I've read in numerous places that chlorine gas is formed when the acid is added, so I'm trying to figure out how to divert that as I don't think my acid system will be well suited for chlorine. The best idea I have come up with is to use CPVC tubing to pass through the lid, the line will then bend past 90 degrees (probably closer to 180 degrees) to trap gases. The line will then bend back upwards and connect to a solenoid valve. Overall, the acid system will resemble a capital letter 'N'. My thoughts are that once the system has settled out, there will be chlorine gas in the line that neither grows or shrinks (significantly). Any thoughts?

I'm also going to try to make my own pinch valve to use instead of a needle valve. A few tests will show if it's consistant enough.

I think I've read through your blogs a year or more ago- but thanks for the reminder: re-reading them has provided valuable insights and reminders! Do you know how well flexible PVC tubing would hold up as a sealing material? I have a slightly different sealing method in mind and I'm wondering if some tubing cut into a narrow strip would last.

Kevin

 

The best method of acid injection I've seen is shown in Swede's blogs. It involves a PVC or CPVC pipe or tube plunging deep into the electrolyte with several small cross-holes drilled in the lower end of the tube. When the dilute acid is dropped into the tube, it slowly diffuses into the electrolyte and the chlorine tends to stay dissolved in the electrolyte where it'll stay in the liquor and make more chlorate.

 

I've found that flexible vinyl (PVC) tubing doesn't hold up especially well in the chlorate liquor. It will for a while but eventually breaks down. I suspect thin-walled Viton tubing would make a better cell seal than even the silicone tubing does.

 

WSM

Edited July 23, 2016 by WSM

[Arthur]

Chlorine is only released when the pH gets too acid even in small localities in the cell, keeping the pH within the usual range by only adding small amounts and adding then often to a turbulent part of the volume. Conc HCl is 36%, can you dilute it to say 10%? This makes the corrosion problems easier to solve for both the container and the metering and delivery system.

 

As a wild thought can you make the pH correction liquid a solution of conc HCl in saturated brine?

[WSM]

Chlorine is only released when the pH gets too acid even in small localities in the cell, keeping the pH within the usual range by only adding small amounts and adding then often to a turbulent part of the volume. Conc HCl is 36%, can you dilute it to say 10%? This makes the corrosion problems easier to solve for both the container and the metering and delivery system.

 

Many amateur electrochemists have had the surprising and unpleasant experience of adding HCl solution (meaning dilute with distilled water) to their chlorate cell (usually hot liquor with mixed amounts of precursor compounds present), only to be "rewarded" with a noxious puff of free chlorine gas!

 

By setting up a specialized system to safely add measured amounts of dilute hydrochloric acid to the cell liquor, at the right feed rate and the proper location (deep, under the surface of the liquor), and at the correct volume per dose, will it be done safely and to the most efficient effect.

 

If you re-read Swede's blogs of his electrochemical adventures, you can see what he used and how he effectively applied it to his system. He and I have gathered commercial materials (through careful eBay searches) and combined them so as to safely inject the needed HCl to the cell in precise and controlled doses so that the current efficiency (CE) will approach the optimum levels possible.

 

These include compatible needle valves (for precise volume control) and compatible valves (electromechanical fluid flow devices) combined with precision timers to accurately control the exact amount of dilute acid applied at regular intervals, and to the right level in our cells to keep things working safely and properly.

 

 

The attached photo shows an early version I made based on the system Swede developed. It involves Teflon (PTFE) valves and a precision timer to operate them. It also involves Kynar (PVDF) fittings (a less expensive but completely compatible alternative to Teflon) and compatible rubber tubing (not shown) to carry the dilute acid portions to the delivery tube, diffusing the acid doses into the electrolyte, deep under the surface, as the cell is running, where it'll react with the electrolyte instead of releasing free chlorine gas.

 

A modification of this system is what I plan to add to my sodium chlorate experiment, beginning with the third and following runnings of the cell.

 

pH control isn't trivial. It involves a LOT of fine tuning and experimentation to get it right, and the balance changes as the run progresses, so it involves plenty of "hands on" control till it's dialed in properly (and it needs to be dialed in for each different setup it's applied to).

 

Fortunately, all the effort is worth it. Also, getting even close to the ideal pH of 6.8, rewards the operator with greatly improved performance and production from his cell.

 

Beware: practice due diligence to avoid overdosing with acid. Any pH below 6.0 and the cell will pump free chlorine gas out like mad. I suggest it's better to under-dose the acid rather than overdo it, and carefully adjust till it gets closer to the ideal levels. Also, remember to constantly monitor the setup. It's need for the acid is dynamic and not static, and will change over the range of the run, so keep careful track of it by regular pH checks.

 

WSM

Edited July 23, 2016 by WSM

[WSM]

As a wild thought can you make the pH correction liquid a solution of conc HCl in saturated brine?

 

I think this view is very simplistic, but in an ideal world it would work. To get it to work realistically, would involve something like a PLC controlled setup with compatible sensors monitoring all the various aspects of the cell parameters separately. I think it could work, but the complexity of making it work correctly is beyond the scope of most amateur's abilities or will to pursue. It's a nice idea, though.

 

WSM

[WSM]

The hydrochloric acid testing was for my acid dosing system; everything thus far looks good enough to use with an actual cell. However, I've read in numerous places that chlorine gas is formed when the acid is added, so I'm trying to figure out how to divert that as I don't think my acid system will be well suited for chlorine. The best idea I have come up with is to use CPVC tubing to pass through the lid, the line will then bend past 90 degrees (probably closer to 180 degrees) to trap gases. The line will then bend back upwards and connect to a solenoid valve. Overall, the acid system will resemble a capital letter 'N'. My thoughts are that once the system has settled out, there will be chlorine gas in the line that neither grows or shrinks (significantly). Any thoughts?

I'm also going to try to make my own pinch valve to use instead of a needle valve. A few tests will show if it's consistant enough.

I think I've read through your blogs a year or more ago- but thanks for the reminder: re-reading them has provided valuable insights and reminders! Do you know how well flexible PVC tubing would hold up as a sealing material? I have a slightly different sealing method in mind and I'm wondering if some tubing cut into a narrow strip would last. Kevin

 

I should add that regular flexible PVC tubing doesn't hold up well. There are other formulations of flexible vinyl tubing that are highly chemical resistant, which should work out really well. They tend to be hard to find in the surplus market, but they're out there.

 

Study the specs of various manufactures to discover which types will be compatible with your proposed uses, and see what you can find. Also, please share what you learn in your searches here for all of us to benefit from. Thanks.

 

WSM

[WSM]

I have a slightly different sealing method in mind and I'm wondering if some tubing cut into a narrow strip would last. Kevin

 

I don't know. I suppose it depends on what the tubing is made of and the physical parameters of its setup in the cell. I know good sealing usually depends on some compression of the seal itself. If I knew more details of the setup you're thinking of trying, I could offer more useful suggestions.

 

WSM

[WSM]

I have to modify my estimation of the amount of NaClO₃ crystals I expect to harvest from the first run of my sodium chlorate experiment.

 

I've already collected nearly 3 kilos of dry crystals and there's more to come. At this point, I need to scale that figure up to between 5 and 7 kilos; but we'll see for sure as the harvesting completes, later.

 

With subsequent runs, I expect the quantity to increase (Yay!!! ).

 

WSM

Edited July 23, 2016 by WSM

[taiwanluthiers]

I'm just curious has any guests seen your cell setup, and do they think it was some kind of a meth lab?

[WSM]

I'm just curious has any guests seen your cell setup, and do they think it was some kind of a meth lab?

I don't know, does meth smell like bleach?

 

WSM

[taiwanluthiers]

I wouldn't know. I don't usually try to find out how to make meth. But normal people see some chemicals and tubes and they automatically assume meth lab.

[WSM]

I wouldn't know. I don't usually try to find out how to make meth. But normal people see some chemicals and tubes and they automatically assume meth lab.

 

I don't know either (deliberately). If anyone asks, I explain that it's my chlorinator experiment (to satisfy my own scientific curiosity).

 

WSM

Edited July 26, 2016 by WSM

[WSM]

I have two small batches of crystals drying and the already "dry" crystals from previous drying cycles are in PET jars. I've harvested crystals from all but the last jar of electrolyte (my experiment to see if they keep growing or stop at some point of equilibrium), which is going on 11 days in the fridge, so far. The crystals are getting larger and looking quite jewel-like, some are very clear. I'll show photos after I harvest them.

 

WSM

Edited July 26, 2016 by WSM

[WSM]

I've started writing Part Fifteen of the Homegrown Oxidizers series and have gotten three pages filled with text and photographs. It explains the things experienced and learned since starting the first run of the sodium chlorate experiment this past two months.

 

There is more to learn and I can use a lot more sodium chlorate for continuing my perchlorate experiments. I would like to see how well (or how long) the perchlorate electrodes will hold up or last in making sodium perchlorate from sodium chlorate. I think that would be useful information.

 

WSM

[TomasBrod]

Good evening

I wonder what are the failure modes of Mixed Metal Oxide anodes? Did that happen to you, dear members?

Can the few micron thick coating fall off and Ti passivate?

With carbon, one must take care of chlorine levels else the electrode turns to dust. With MMO are there any other dangers?

[Arthur]

MMO has proved to be robust so far, the stumbling blocks are attempting to get the chloride electrolysed to completion.

[WSM]

MMO has proved to be robust so far, the stumbling blocks are attempting to get the chloride electrolysed to completion.

 

Remembering something Swede said, MMO is very chemically and electrically tough, but it can be scratched. If it is scratched or physically damaged, generally the titanium passivates, or self-heals (part of the nature of "valve metals").

 

As Arthur says, "attempting to get the chloride electrolysed to completion" , is a mistake. One should start with as high a chloride level as possible (up to about 16%), but not run it much below 10% or 8% chloride. Trying to run the cell down to 0% chlorides is very hard on the electrodes, and yields less and less chlorate as the run continues (dramatically diminishing returns after a certain point).

 

WSM

Edited July 30, 2016 by WSM