making potassium (per) chlorate

[WSM]

Attached is the crystalizer for the monster. To allow enough room to harvest on a casual basis (like once a week, rather than constant attention) it had to be huge. This thing holds twenty five gallons when 4.25" full. I was lucky to find a source of affordable clear PVC sheet and have a skilled (plastics) craftsman assemble it for me. The other advantage of having the crystalizer so large and shallow is using passive, rather than active cooling.

 

I'll try to document further progress and developments here so others can benefit from lessons learned in the effort.

 

Edited April 3, 2010 by WSM

[TheSidewinder]

Oh, I am DEFINITELY liking the looks of this......

 

Nice job!

[Fluorescein]

Because it becames hard so get potassium perchlorate I decide to build a perchlorate cell too.

The substrate of the anode is a 1mm titanium plate which is treated in 6n HNO3 and electrolytic coated whith PbO2 in a solution of Pb(NO3)2 and sulfamic acid

German patent:

elektrode.pdf

 

A test preparation of perchlorate is followig, but I don`t like to handle substances like Pb(NO3)2, so my question is if the PbO2 coated anodes from a fresh car battery will work too?

[Bonny]

Because it becames hard so get potassium perchlorate I decide to build a perchlorate cell too.

The substrate of the anode is a 1mm titanium plate which is treated in 6n HNO3 and electrolytic coated whith PbO2 in a solution of Pb(NO3)2 and sulfamic acid

German patent:

elektrode.pdf

 

A test preparation of perchlorate is followig, but I don`t like to handle substances like Pb(NO3)2, so my question is if the PbO2 coated anodes from a fresh car battery will work too?

 

AFAIK battery anodes will not work. Maybe Tentacles or Swede can explian. Take a look at the Science Madness forum, I think there is some info there.

[Arthur]

Getting to that sort of scale you really should consider some safety matters. Consider what would happen if the cell jar split or there was a leak, there would be a hugely inflammable area and nothing would grow in that area and in any of your footprints for years.

 

The cell current efficiency is greatly improved by pH control, the electrical system efficiency is dependent on the quality of the wire and the connectors- and keeping the fumes off them.

 

Read "Swede"'s blog in this forum and also read the posts on the Science Madness forum.

 

Chloride to chlorate works with MMo and Ti electrodes. To go the the Perchlorate stage needs either platinum or Lead dioxide as the anode. The lead dioxide HAS to be plated directly onto a substrate usually MMO, read Swede's method

Edited April 3, 2010 by Arthur

[WSM]

To continue my saga of the monster: My plan for the electrodes is to use MMO mesh obtained from Swede for the anode and titanium plate(s) for the cathode. I've acquired some 1/2" diameter titanium tubing to spot weld to the electrodes and practiced the technique and they came out great (according to Swede; Thanks, buddy!). I filled the tubes with lead-free solder and mounted stainless studs for attaching the lugs on some welding cables connected to a heavy duty DC power source. I need to experiment to see how much current will actually be passed into the salt solution in the reaction chamber. I plan to use PVDF compression fittings to seal the electrode leads into the system (as Swede's excellent blog suggests) to eliminate the pesky and damaging salt creep that has plagued my earlier cells. I am also minimizing salt creep around the reaction cell lid by applying a silicone seal on the lid using aquarium silicone tubing fixed in place with RTV.

 

To facilitate the measuring of current (and potential), I purchased digital volt and amp (with shunt) panel meters on eBay. I tested them and they are nice plus easy to read. I also got some watt-hour meters to measure the total power consumed during the whole process (how much did that chlorate really cost you?!).

 

Because this is an effort to make salts continuously, I plan to automate the system as much as is practical. I am monitoring temperature, pH, power, voltage and current. I plan on pH control and am working on a way to use an aquarium pH controller without poisoning the sensor. My ideas revolve around a small test chamber inside the reaction chamber (to help control the temperature and help eliminate crystal contamination of the test chamber) and then isolate the pH probe from electrical current in the cell by staging the injection and purging of the liquor samples in a way that allows constant sampling without hammering the sensor. I'm still working out the details but hope to ultimately find success. Till I work the bugs out of active pH control, I plan to go ahead with timed acid injection and periodically test pH to see if I can maintain the pH goal of 6.5-6.8. All those using the method have succeeded reasonably well so I'll start there while working on the sensor isolation system (more on that as it develops).

 

The PVC tank and crystallizer (as well as all essential plastic components) are bonded with industrial solvents and binders rather than plumbing glues to overcome the weeping joints I experienced with the plumbing products. Great pains were taken to make very solid tanks to avoid any structural problems. If problems do develop, I plan to drain, clean, dry and reinforce with additional material as needed. I need to put an active vent (possibly by aspiration) on the reaction chamber lid to safely remove unwanted products of the project (hydrogen, chlorine and other hazardous fumes or vapours). Active dilute HCl insertion, make-up water/ salt solution addition are supplied by pumps (either used commercial [metering or peristaltic] pumps c/o eBay or by home-made diaphragm pumps, all to be determined as I assemble the components and run the system).

 

Basic Cell Design.pdf

 

The tubing used will be either PTFE, FEP or silicone through PVDF or PP compression fittings, depending on the application and compatibilities where applied. I have to admit I've spent more time planning and developing than building, till now. I'm starting to assemble the components and getting ready to do some trial runs. For water, I'm using tap water run through an RO system to remove as many dissolved solids as possible, to eliminate as many contaminants as I can without the expense of using bottled distilled water. The reverse osmosis system reduces the dissolved solids in my tap water from 300-400ppm (depending on the time of year) to less than 20ppm (near enough to pure for my purposes ). The salt I'm using is potassium chloride water softener salt (not the best, just the most readily available).

 

I'll try to add more about the monster as I think of it. Sorry about the rambling nature of these posts, but I'll put it all together as a monograph later on.

[pdfbq]

Hi All. I have this problem

My wild guess it its calcium and it does not conduct.

I had the anode submerged for about 10 minutes in HCl but that did not do much.

Does anybody know if for instance submerging in warm HCl or using Nitric or Sulfuric accid is possible without destroying the MMO layer?

Thanks

[WSM]

Hi All. I have this problem

My wild guess it its calcium and it does not conduct.

I had the anode submerged for about 10 minutes in HCl but that did not do much.

Does anybody know if for instance submerging in warm HCl or using Nitric or Sulfuric accid is possible without destroying the MMO layer?

Thanks

 

Hi pdfbq,

 

This is just a wild guess, but soak it in white household vinegar over night (8-12 hrs) then flush it with HCl and see if that helps. Actually, I imagine soaking in HCl alone for a long time shouldn't do any harm to the MMO, if I remember Swede's blogs well. Swede soaked the MMO in HCl to remove an unknown brown smut on the anode materials with no detectable damage to them. It's worth a try. Good luck.

 

WSM

[FrankRizzo]

If it's a calcium salt, the original HCl soak would have removed it immediately. Did the crystals grow on the mesh while submerged in the cell?

[Mumbles]

I think about the only thing that a HCl soak wouldn't remove is PbCl2. I don't think it forms a soluble complex salt. Do you think that the MMO is being slightly corroded by HCl or Cl2? You can make PbCl2 from PbO2 by action of HCl (forming PbCl2, H2O and Cl2). A vinegar (or stronger) soak should hopefully be able to get it off by overpowering the equilibrium.

 

[edit] Nevermind, it does form a soluble complex, [PbCl₄]^2-

[FrankRizzo]

I was thinking maybe the MMO became compromised, and the mesh was growing titanium oxide crystals.

[50AE]

As for my anode, I did a test with an ommeter.

From point A to point B, there were 1-2 oms of R. A to B 4" distance, it was about 6 oms.

Maybe something has got between the MMO and the Ti ?

[ausfire]

Recently i have being trying to get hold of a power supply to upgrade from the computer power supply's i have been using in the past, After daily ebay searches for at least 2 months i managed to pick this beast up.

Anyway its a lambda EMS 13-75-1-D, And will do 0-13 volts at 0-75 amps. One things got me thinking though, All the manufactures markings indicate that this unit is 115VAC, But there is a sticker on the top stating "Attention 220 voltage" so Ive contacted the seller regarding this. I bought this under the understanding that it was 115VAC should it turn out to be 220VAC it will be even easier to wire up.

[pdfbq]

If it's a calcium salt, the original HCl soak would have removed it immediately. Did the crystals grow on the mesh while submerged in the cell?

Yes, while running.

 

I was thinking maybe the MMO became compromised, and the mesh was growing titanium oxide crystals.

Can be. I had some test for 1 hour in 30% HCl 15C. Nothing.

 

I'm no chemist so I have difficulties searching on these subjects on the internet. I find things like this:

 

- TiO2 has various solubility in different acids or acid mixtures depending if it

- is hydrous, anhydrous or calcined. You can try hot sulphuric acid (1M) which

- should dissolve quite well the TiO2. Or if you have calcined oxide it dissolves

- in a mixture of hydrochloric:nitric acids (3:1) also known as aqua regia.

 

But I have the feeling that the MMO coating will be gone as well after an aqua regia bath.

I will try the hot sulphuric acid but tonight i am testing vinegar.

 

edit: Sigh..

200C sulfuric acid did not do more damage than scaring me .

Then I made a solution of 30% HCl and 53% nitric acid in a 3:1 ratio. It disolved some MMO but not the white stuff...

 

Swede, Help!

Edited April 7, 2010 by pdfbq

[Ventsi]

Wow, did you grow diamonds or something..

 

I had some white buildup on my cathode but I easily scrubbed it off with a Brillo pad and some steel wool. Just though I'd say. But I wouldn't scratch the anode, it might damage the MMO.

[gordohigh]

If that was a calcium carbonate film on there it would be immediately disolved by the acid. Vineger would attack it but very slowly, possibly over a 24 hour period but a watered down muriatic acid would fizz and disolve it very quickly.

 

I think Mumbles might be on to something.

[pdfbq]

There is no Pb in the cell i think. In the cell is Ti, NaCl (foodgrade but it has some white contamination, no idea what that is), tap water and the MMO stuff.

I'm testing here on another old anode with the same white stuff. Its not very clear on the picture but below the 'water line' some MMO has disolved in the HCl Nitric acid solution (you can see some Ti shinig through) and the white stuff still there.

I'm reading about calcined oxides. Does anybody know what that means?

 

I think have to switch to distilled water to start with.

[WSM]

There is no Pb in the cell i think. In the cell is Ti, NaCl (foodgrade but it has some white contamination, no idea what that is), tap water and the MMO stuff.

I'm testing here on another old anode with the same white stuff. Its not very clear on the picture but below the 'water line' some MMO has disolved in the HCl Nitric acid solution (you can see some Ti shinig through) and the white stuff still there.

I'm reading about calcined oxides. Does anybody know what that means?

 

I think have to switch to distilled water to start with.

 

If your water is the problem, then starting with distilled water will be a quick fix. If that doesn't do it use another source for the salt. Most salt used for food has other stuff in it. Sea salt will have many other things in there and regular table salt usually has freeflow agents or some form of iodide for health. If you have salt available for swimming pool chlorination or any source for "pure" salt (NaCl), that would be a good place to start if the salt is the culprit. Good luck and let us know what you learn.

Edited April 8, 2010 by WSM

[50AE]

We definitely need an MMO expert

[Mumbles]

Canning salt is pure NaCl (I think), if you guys ever want to do a test.

 

The use of table salt is interesting. It could be Lead (II) Iodide. That shouldn't dissolve in anything but HI solution.

 

[edit] Never mind the lead iodide suggestion. I remembered a key fact, in that it's yellow, and soluble in hot water. Have you tried boiling the anode in water? If it's a lead halide, it should dissolve partially in hot water.

 

I seem to remember Bonny getting a purple solution, which might be due to Titanium (III) Chloride. If you can make that, the white stuff very well could be TiO2.

[bikemaster]

It is sad to say, but you anode seem to be dead...

 

I got the same problem some month ago, you can see some bad pictures there : http://www.sciencemadness.org/talk/viewthread.php?tid=5050&page=30

 

Has I said the quality of the picture is not really good, but we can see that in middle of the anode the black color of the mmo switch to gray (almost white) and this is not over exposition from the camera flash. We can also see a small part of the anode that is totaly erode (on the right). We can also think that it is gray at the weld, but this is only over exposition...

 

That was not the first time that it where some deposit on the anode, but before this time, all was easily wash with a brush or a bath of HCl. Sadly this time it didn't work.

An other observation that I make is that when I start the anode (when it was erode) the SS cathode was rusting really fast (30 min and all the cell was black/red). Usually, even after one month only a small green teint was there.

My dianostic was that the mmo was slowly eroding with time and went I try and new power supply (12V).... The anode was not able to passivate so it start to erode really fast.

 

So if you can tell us what was your cell voltage, electrode spacing, how much time your use anode, it will help to know what is your probleme.

 

I don't want to break you expactation, but if it is tiO, it is not over the mmo, it was the titanium under that create a protection because the mmo is gone...

If you are able to remove all the tiO, you can always use the anode as a cathode or protect the expose ti with a tin oxide coating and use it to make a lead dioxide anode .

 

If you want a really good way to see if it is TiO, just try a resistance test, it will tell you all what you want to know. It you don't have a multi meter, your can always built a small device that tell you the energie that is able to pass into you anode.

How to use : Contact the two wire together (light 100%), touch two untouch place of the anode (light is suppose to light...), touch at least one spot of the anode that have been erode (if the light intensity is lower that the second test, you have good chance of TiO...

 

Good luck

 

cheap and unprecise omh meter.bmp

[TrueBluePyro]

I just made some better connections for my cell. Found some thicker wire and used it as well. It's looking much better now.

Edited April 9, 2010 by TrueBluePyro

[bikemaster]

Wow! This is much better! That will really improve your cell result.

[TrueBluePyro]

Thanks, they look much better as well . Also I can see that it is working alot better now that I have these connections.

[50AE]

No luck with myanode guys. I tried putting in boiling water, boiling vinegar, boiling HNO3 solution, boiling H2SO4 solution, boiling HCl solution and a boiling mix of all.

However, it seems its resistance in electrolyte with the inversed polarities is much lower. I can measure 200 oms inversed, and 200k to megaoms in correct polarities.

 

I'll be using distilled water from now on. I hope the fertilizer grade KCl has nothing to do with hurting my anode.

Edited April 9, 2010 by 50AE