making potassium (per) chlorate

[TomasBrod]

what step am i missing to get sodium perchlorate ?

Memo, It is known that MMO electrodes are not good for making perchlorates. The chlorates and perchlorates site has a list of usable anode types. From what I read here and elsewhere, perchlorates are made with anodes capable of doing so. For example: platinum or lead dioxide. Because presence of chloride ions when making perchlorate can cause failure of anode, perchlorates are made from chlorate salt solution which has been cleaned of chloride salt.

[Arthur]

If you use a lead dioxide electrode then it will make Na chlorate til the Na chloride concentration is running low then Na perc will also be made til the chloride concentration becomes negligible then only perc will form.

 

If you use MMO (DSA) as an anode then production stops at chlorate because of the properties of the anode. Don't waste time or life on MMO and perc.

 

If you use a Platinum anode it will be destroyed in the presence of chloride ions, so first make Na Chlorate with MMO then chill and filter the solids out and finally redissolve the solids (Chlorate) and electrolyse them to perc gently Platinum anode and Titanium cathode. Fortunately making chlorate takes three times the current that making perc from chlorate takes so use a very small current to preserve the platinum (coating).

 

For KClO3 start with MMO and KCl

For KClO4 start with MMO and NaCl make NaClO3 then extract the chlorate and dissolve it into a cell with a Pt anode and run that to perc.

[WSM]

If you use a lead dioxide electrode then it will make Na chlorate til the Na chloride concentration is running low then Na perc will also be made til the chloride concentration becomes negligible then only perc will form.

If you use MMO (DSA) as an anode then production stops at chlorate because of the properties of the anode. Don't waste time or life on MMO and perc.

If you use a Platinum anode it will be destroyed in the presence of chloride ions, so first make Na Chlorate with MMO then chill and filter the solids out and finally redissolve the solids (Chlorate) and electrolyse them to perc gently Platinum anode and Titanium cathode. Fortunately making chlorate takes three times the current that making perc from chlorate takes so use a very small current to preserve the platinum (coating).

For KClO3 start with MMO and KCl

For KClO4 start with MMO and NaCl make NaClO3 then extract the chlorate and dissolve it into a cell with a Pt anode and run that to perc.

 

These comments are correct, but the first part has omitted several crucial details.

 

If you use an LD anode, it can produce perchlorate; BUT, to go directly from chloride all the way to perchlorate takes a particular type of lead dioxide anode, plus a catalyst which is destructive to titanium. This means no LD over titanium electrode will survive.

 

The article Arthur is referring to specifies using LD over graphite (or GSLD as spoken of on APC) which the authors (electrochemists in India) had to make themselves, plus using sodium fluoride as a catalyst. In the article, they describe how as the (sodium chloride based) cell runs, the chlorate increases as the chloride decreases, to a point where the chloride is completely exhausted, and then the chlorate decreases as the perchlorate increases. The perchlorate eventually dominates the cell as the chlorate drops to very low levels.

 

They ran two experimental cells, one smaller and then a larger one, as a proof-of-concept for later possible expansion to industrial levels.

 

If we try this with LD or platinum on titanium, the fluorides will eat the titanium and destroy the cell. Titanium cathodes may survive, so long as the current is applied (cathodic protection), but as soon as the power is off it'll be compromised, probably badly.

 

I would love to try their system, but lacking GSLD anodes, I'm unable to at this time. Perhaps some time in the future, I'll give making GSLD anodes a try (unless I can find one to buy), then see if I can duplicate their experiment. We'll see...

 

WSM

Edited December 24, 2018 by WSM

[WSM]

Memo, It is known that MMO electrodes are not good for making perchlorates. The chlorates and perchlorates site has a list of usable anode types. From what I read here and elsewhere, perchlorates are made with anodes capable of doing so. For example: platinum or lead dioxide. Because presence of chloride ions when making perchlorate can cause failure of anode, perchlorates are made from chlorate salt solution which has been cleaned of chloride salt.

 

True, particularly with platinum anodes.

 

My work in making perchlorates has involved starting with sodium chlorate. Then converted to sodium perchlorate, I've neutralized the residual chlorate, then made potassium perchlorate by double exchange with potassium chloride.

 

My efforts since then have been making enough high purity sodium chlorate, to make (high purity) perchlorate production on an amateur scale viable.

 

It's a great challenge, and very fun; but I'm much too busy with life and other pursuits to devote the time needed to proceed quickly with it. Maybe when I retire?!!

 

WSM

[WSM]

what step am i missing to get sodium perchlorate ?

 

Starting with sodium chlorate (with no chloride contamination). I've done it with both Pt over Ti, and LD on Ti.

 

WSM

Edited December 24, 2018 by WSM

[WSM]

Merry Christmas to All.

 

I hope to make more progress in the coming year (with my electrochemistry experiments), but I have a lot of other things going on at the same time, so we'll see...

 

I'll post my progress here (APC) as things move forward.

 

WSM

Edited December 24, 2018 by WSM

[memo]

hope all had a great holiday

[PTFE]

Hey guys.

A late, but happy new near to all of you.

 

I'm reading again through this thread and I'm at page 104 now.

 

Since some of you, especially WSM mentioned to use IWAKI Pumps taken from the photo-industry some questions came in mind.

The IWAKI MD-10 Is made out of Polypropylene and im courious how long it will last if used to pump ~80°C hot Electrolyte.

Does someone had failures due to corrosion when using this kind of pump?

 

Greetings,

PTFE

 

PS: what has happened to this thread? No replies anymore.

I have moved 2 times in the past months and have to build up my workshop again. so it will take roughly until the end of the year until my next cell is going to be set up.

[Arthur]

The original mention of Iwaki bellows pumps was mine! I worked in photo processing for some years. We never had bellows or valves fail in service unless they were accidentally physically damaged (poked prodded etc). My original suggestion was that they be considered for periodic acid addition in a pH controlled cell. Make a pump run for 1 - 100 seconds in every hour, Or Make a pump run for every so many amphours. Iwaki bellows pumps have selectable bellows diameters AND can be powered from on cycle to 100% duty cycle making the volume flow controllable over a wide range.

 

The bellows pumps are NOT suitable for circulation, except in trivially small containers. With a cell of moderate volume and sufficient current, the natural hydrogen lift causes sufficient agitation for all purposes. If you need to pump cell liquor then several pumps are available, Magnetically coupled pumps usually are resistant to many solutions, but don't always have a long life. But you should consider the time taken to make your annual usage quantity.

[PTFE]

Mh, thank you for your advice. Can you or anyone else too help me with a suitable pump for the use as circulating pump.
Previous I showed my self built 300A Psu and got another two of the 5V/150A Smps.

All combined i have the ability to use 5V/600A smooth DC current and to use it i have to apply an active cooling system. The easiest way will be to pump the electrolyte out of the cell instead of pumping cooling water inside.

To archive high power cooling, i would have to use a large cell to provide a large cooling spiral but instead a small cell could be used and a big cooling tank will be more suitable.

[Arthur]

I'd always consider standing the cell in a large tank of water and keeping that outer tank moving to cool the cell. Pumping water is so much easier than pumping electrolyte.

[WSM]

The Iwaki magnetically coupled pumps may be available with PVDF housings. They wouldn't be cheap but would certainly hold up better than many other polymers.

 

PTFE would likely be best but also cost considerably more.

 

WSM

[Arthur]

The mode of failure in all the magnetically coupled pumps I ever replaced (dozens!) was the failure of the centre spindle and the rotor to properly lubricate with the various chemicals in which they were permanently immersed. The centre spindle was often ceramic, most inert but still needed replacement every few years.

[WSM]

The mode of failure in all the magnetically coupled pumps I ever replaced (dozens!) was the failure of the centre spindle and the rotor to properly lubricate with the various chemicals in which they were permanently immersed. The centre spindle was often ceramic, most inert but still needed replacement every few years.

That's a good point. Since most of us work our systems intermittently, I hope the pumps will last longer. I know I haven't worn one out yet; but, maybe in the future...!

 

WSM

Edited March 1, 2019 by WSM

[Arthur]

Mag coupled pumps need to be clean and dry inside when put into storage. Anything with dissolved solids drops just enough crystals between the rotor and the shaft and is either solid when next turned or the nearly solid bearing grinds itself to and early death on switch on.

[WSM]

Mag coupled pumps need to be clean and dry inside when put into storage. Anything with dissolved solids drops just enough crystals between the rotor and the shaft and is either solid when next turned or the nearly solid bearing grinds itself to and early death on switch on.

 

I HAVE noticed that if Crystal's tend to drop out in the plumbing connected to the magnetically coupled pump, they can jam it, preventing flow.

 

The trick is to design the system to avoid such problems.

 

WSM

[WSM]

I'd always consider standing the cell in a large tank of water and keeping that outer tank moving to cool the cell. Pumping water is so much easier than pumping electrolyte.

 

This is true.

 

If you take this route, you may want to consider a closed loop system, using a pump plus a radiator and fan cooling system to dissipate heat.

 

I'm thinking of something similar to those used to water-cool computers. The various components are available on Ebay and can be had for bargain prices if you shop carefully.

 

Can you show us what you have in mind, either by photo or drawings? It sounds interesting.

 

WSM

[MadMat]

I have created a chlorate cell and am creating NaClO3, which I will convert to KClO3.

 

I am using 2 lead electrodes the anode has a layer of PbO on it, and I am wondering if that will work. In all of my readings I have seen PbO2 used but never PbO.

You can create a lead dioxide anode by electrolyzing lead to form the coating. Generally, 10% sulfuric acid is used as the electrolyte for forming the lead dioxide coating. The main problem with these kind of anodes is that the coating has a tendency to flake off after continued use. I have been experimenting trying to develop a process that produces sound anodes, but with little success, so far. There are so many variables to work with, it may take some time.

Edited May 19, 2019 by MadMat

[WSM]

You can create a lead dioxide anode by electrolyzing lead to form the coating. Generally, 10% sulfuric acid is used as the electrolyte for forming the lead dioxide coating. The main problem with these kind of anodes is that the coating has a tendency to flake off after continued use. I have been experimenting trying to develop a process that produces sound anodes, but with little success, so far. There are so many variables to work with, it may take some time.

 

Making lead dioxide this way makes the spongy ALPHA form, which, as you say, tends to fall apart in use.

 

The preferred form of lead dioxide is the BETA form, which is a hard crystalline material that holds up much better in the perchlorate cells.

 

Swede went to great lengths to coat the MMO/titanium substrate with beta-form lead dioxide, and succeeded!

 

WSM

[memo]

wsm

can you tell use what the process was ?

[WSM]

wsm

can you tell use what the process was ?

Check Swede's blog dated 16 January 2009.

 

WSM

Edited May 21, 2019 by WSM

[Arthur]

Swede did all the necessary research for chlorate cells, perc cells, and all the appropriate electrodes. There is a tremendous amount to be gained from reading his posts and his blog.

[WSM]

Swede did all(?) the necessary research for chlorate cells, perc cells, and all the appropriate electrodes. There is a tremendous amount to be gained from reading his posts and his blog.

Swede definitely did a LOT of research, which fortunately he shared with us here.

 

His research was by no means complete, by his own admission.

 

That said, we owe him a debt of gratitude for all that he did share with us. I, for one, try to share much of my research and thoughts to "pay it forward ", as it were; and I hope we all will, that all may benefit thereby.

 

WSM

Edited May 27, 2019 by WSM

[WSM]

One of the interesting details occurring to me as I've pursued making chlor-alkali salts (oxidizers), is the problem of increasing amounts of contaminants when reusing the electrolyte of former runs.

 

I've considered one possible solution to this problem being the purification of all the materials used.

 

This may seem tedious and unnecessary, but I contend the end results may well be worth the effort.

 

I'll enumerate the details of my thinking on this topic more in future posts...

 

WSM

Edited May 27, 2019 by WSM

[WSM]

One of the interesting details occurring to me as I've pursued making chlor-alkali salts (oxidizers), is the problem of increasing amounts of contaminants when reusing the electrolyte of former runs.

I've considered one possible solution to this problem being the purification of all the materials used.

This may seem tedious and unnecessary, but I contend the end results may well be worth the effort.

I'll enumerate the details of my thinking on this topic more in future posts...

WSM

Consider, if you will, the results of several runs of a potassium chlorate cell, where instead of starting with fresh electrolyte every time, you take the depleted electrolyte solution and "recharge" it with KCl and keep running it over and over.

 

Contamination will accumulate in ever increasing levels with every run.

 

My source of potassium chloride is usually water softener salt, and trust me, it's not as pure as you would hope. For water softening purposes, it doesn't need to be (though your water softener would run much better if it were!).

 

Taking the typical materials available to us into account, I often see dark matter in the nuggets of salt, and those are just the contaminants I can SEE. There is usually more that can't be seen.

 

I'll discuss these contaminaing materials further, plus my thoughts on removing them more later...

 

WSM

Edited May 27, 2019 by WSM