making potassium (per) chlorate

[WSM]

I do like the idea of the dispenser/diffuser tube that swede spoke of. I just am not sure how I want to set up a system (one that works like a washer machine timer) . I think that i will use it to operate a simple solenoid, with a dump valve that runs into a drip tube , that essentially goes into the cell. It will slowly drip over a timed period.

 

Swede showed (in his Blog) a highly accurate digital timer which is supremely variable. The cost is less than $40 delivered. The internal contacts can drive a relay which will control a solenoid operated valve and feed through a needle valve to accurately meter out the exact amount of dilute acid needed. The wetted parts should be Teflon (PTFE) or Kynar (PVDF) which can handle the acid indefinately. Come to think of it, even PVC should handle dilute HCl without any problems.

 

 

This is my copy of the system Swede designed. Most of the components were purchased on eBay or locally from a big box home center. You gotta love eBay, but it takes patience and a little skill sometimes, to score the really good deals. Swede lamented that more folks here don't look to eBay as a source.

 

The timer has many possible setups available and one allows you to open and close contacts for a settable time every hour and then reset, so predetermined hourly injections are possible for as long as you want it to run. The timer is a very cool item to add to your arsenal of industrial tools .

 

WSM

Edited August 22, 2011 by WSM

[pdfbq]

Yeah, its a shame that almost all the people who just "get it", are never there to help anymore.

Behave damn it!

People, including me, are worried about Swede. Get a bit more adult before posting your totally irrelevant, non contributing replies.

He was one of the most helpful members. Nobody knows what happened to him and and why he is not here anymore, I fear the worst but hope and pray nothing happened to him or his family.

[Arthur]

IF you have a large cell with a relatively low current then the pH control addition per day would be small, so one or two additions daily would suffice. If the cell were more productive then over time the pH control addition per hour can be determined experimentally, add 11 of these per half day automatically and do a pH test and make the 12th addition by direct determination.

 

If your cell uses 120ml per 12 hours then add 10ml hourly and check the pH and fine tune the rate every so often.

[WSM]

Behave damn it!

People, including me, are worried about Swede. Get a bit more adult before posting your totally irrelevant, non contributing replies.

He was one of the most helpful members. Nobody knows what happened to him and and why he is not here anymore, I fear the worst but hope and pray nothing happened to him or his family.

 

I too was worried about him (I'm still concerned, but less worried), till I got a message from Tentacles saying he ran into a recent posting by him on a different non-pyro site. I don't know what changed in Swede's life, but I hope it wasn't catastrophic. I miss communicating with him; he's very insightful.

 

WSM

Edited August 22, 2011 by WSM

[WSM]

IF you have a large cell with a relatively low current then the pH control addition per day would be small, so one or two additions daily would suffice. If the cell were more productive then over time the pH control addition per hour can be determined experimentally, add 11 of these per half day automatically and do a pH test and make the 12th addition by direct determination.

 

If your cell uses 120ml per 12 hours then add 10ml hourly and check the pH and fine tune the rate every so often.

 

Hi Arthur,

 

It sounds reasonable to me. I'll try Swede's rule-of-thumb first, but your method should work as well. The trick is knowing just where to start. You certainly don't want to over-do it! Under-doing it just means things aren't as efficient as they could be. Over-doing it means watch out for free chlorine coming out !!!

 

WSM

[Arthur]

In an old fashioned factory, the ammeter would have crayon marks at operating currents suggesting different addition rated to control pH, but the "lab" would keep an eye on the pH every few hours. In a modern factory expensive pH and ion selective electrodes would be used to monitor cell parameters and control the computer for the dosing pumps.

Noting the cost of the electrodes and dosing pumps we will continue to use some of the older lab methods I suspect!

[WSM]

To bad Swede has gone AWOL from the forum. But he had his reasons and I believe they were good ones.

WSM I know you been here adding to this forum for a long time (13 September 2009 - 09:09 AM ). And the information you have added has helped many here. That is what this is for and as always we look forward to hear from you.

When Swede was here we were-or I should say "I was" looking for ways to add pH to the cells in a few diferent ways and as I said above that the ideal is dated. But it still stands as a way to control pH level. It is the live and learn thing that we all go thru with the help of our friends. I find that it has help me and I feel that it has helped other as well.

There are afew other areas that information was added in the forums some good some bad but it is there if one is willing to look for it.

 

I always thought it would be best to pump the acid or dilute acid into the cell. I had to agree with Swede's suggestion of diffusing it in when I remember how I practically gassed myself by dumping a shot of acid in an active cell one time !

 

When Swede published his idea to use a gravity feed system, to prevent the pump feed tube from pumping empty for part of its run due to it emptying itself between injection periods (causing inaccurate dosing); I didn't immediately embrace the idea. I had to reconsider the idea when I reallized how energy efficient the concept is. I wondered why I was so concerned about pumping the liquor around and didn't think pumping the make-up water or acid was such a big deal.

 

I admit I was hasty there but have come around (you've seen my opinion recently). We don't always get it when a new idea, or one counter to our thought process appears. It's best not to rush to judgement, but consider each thought on its own merit. We then are open to other avenues of thought and can adapt and grow.

 

You're right, Pat. The idea does have merit. I just feel implimenting it would be more work than I'm willing to invest in it. If there were an off-the-shelf item, compatible with the liquids involved, and at a good value; I'd have to take another look and see if it wouldn't be a better way. Thanks for suggesting it again.

 

WSM

[WSM]

In an old fashioned factory, the ammeter would have crayon marks at operating currents suggesting different addition rated to control pH, but the "lab" would keep an eye on the pH every few hours. In a modern factory expensive pH and ion selective electrodes would be used to monitor cell parameters and control the computer for the dosing pumps.

Noting the cost of the electrodes and dosing pumps we will continue to use some of the older lab methods I suspect!

 

If cost were no object, we'd be using platinum electrodes . Dosing pumps aren't nearly as hard to come by as expensive electrodes or especially chlor/alkali cell resistant pH probes! But still, we have to pay the electric bill. May as well make the system as easy on the pocket book as we can, Right?!

 

WSM

[oldmanbeefjerky]

I already have my own idea for introducing acid into the cell. And although its not completely reliable, it does have the advantage of being extremely simple and in my case almost free.

I just though briefly, why not use a pipette which slowly gets squeezed over time to introduce acid into the cell , since the tube is too small for any acid to drip through into the cell. but of course that would never work, for one reason and that is that the hydrochloric acid would need to be so concentrated that it would either eat through the pipette, or it would evaporate and the gas would force the acid out of the cell too quickly, so i came up with another similar idea.

 

i would use a solenoid, to push down on a pump once every 15 minutesr via a retarded alarm clock triggering a relay which for some reason keeps alarming every hour if i dont manually press the alarm button, which will squirt some dilute hydrochloric acid into the cell through a very thin tube too thin for the liquid to seep through, so keeping it perfectly drip tight wont be an issue, and that should keep the ph of the cell about right. i will though need to make sure that acid being introduced will bring the ph to about neutral, and that the amount of acid introduced must be completely used up over the 15 minutes. as a safety precaution the relay cannot trip if there is current passing between two carbon electrodes which sit at the top of the cell, to ensure it does not overflow if something goes wrong. of course the reservoir of acid that the squeeze pump will be getting acid from will never have more than enough acid in it to completely replenish the needs of the cell, so over acidification will be highly unlikely.

 

First i need to find out how much chlorine is lost in 15 minutes when the cell is run at neutral, and how much water is lost. and that will be how much dilute acid i will add to the cell per pump.

 

The acid is pumped into the cell wit the same kind of mechanism used to prime a petrol engine with fuel, but i will make sure that it is not damaged by the acid.

 

 

WSM, i have established that it takes me 1.8KWH to make 220g of potassium chlorate, how inneficient would you say that this is?

Edited August 23, 2011 by oldmanbeefjerky

[ausfire]

oldmanbeefjerky,

 

From what you have provided and the assumption that your cell is running at 5v your cell efficiency (CE) is 80.1%. The establishments you said you made must be well off their true values as it is impossible from a cell containing no pH control to have a CE greater than 66.6%.

 

-Ausfire

 

 

[oldmanbeefjerky]

whoops, i miscounted, it was 2.4KWh i forgot to include the afternoon i left the cell running before i packed it away. How do i measure the cell efficiency exactly? what is the formula or equation?

 

 

By the way, if anyone was still interested in knowing, i have confirmed, that smearing grease around the electrodes connection plates, does stop the salt climbing up the plate and reaching the connection, ive found however normal water dissipating general purpose lubricant (from a spray can) evaporates away over time, however engine oil ( the kind that goes inside an engine or sticks to the hot parts of an engine without burning) does not. its completely invisible on the electrode right now, the only way to see where i smeared the grease is where the salt has stopped climbing up!

All in all i am no longer bothered by the risk of salt finding its way up to my connections and ruining them! Has anyone else ever actually tried this?

Edited August 23, 2011 by oldmanbeefjerky

[WSM]

whoops, i miscounted, it was 2.4KWh i forgot to include the afternoon i left the cell running before i packed it away. How do i measure the cell efficiency exactly? what is the formula or equation?

 

Swede shared this with me:

 

where mass = grams:

Process Formula for CE in %

Na Chloride to Chlorate 151.08 * mass/Ah

Na Chlorate to Perchlorate 43.78 * mass /Ah

K Chloride to Chlorate 131.22 * mass /Ah

K Chlorate to Perchlorate 38.69 * mass /Ah

Na Chloride to Perchlorate 175.10 * mass /Ah

 

If my math is right, I calculate it at 60.1425% CE. I may be wrong, but I figure 2.4kWh is 2400 watts/hour. I then use Ohm's law and divide by 5 (Volts) and get 480Ah. Now the mass (220 grams) multiplied by the number above (131.22) is: 28868.4 and when you divide by the Ah (480) you get just over 60%CE, presuming you're converting KCl to KClO₃.

 

Now Swede was always careful to include the dissolved chlorate still in the mother liquor. I don't know if it's accurate to extrapolate that from the charts available in the classic texts, but it's at least an educated guess and a corrected CE may be had from that.

 

My head hurts now, I think I'll quit .

 

WSM

[oldmanbeefjerky]

Thanks, this is a massive help!

[Arthur]

Swede's blog and posts contained most of the chemistry, engineering and maths needed to do this perc cell thing. However you really do have to read it all and understand it to get best benefit.

[oldmanbeefjerky]

I am rather sad right now.

i just weighed out the dried chlorate and my estimate was far off. i had exactly 101g of chlorate precipitating out of my cell, which brings my CE to about 30% or so if i include the chlorate still in solution.

as i said before. next batch i will record everything to get a more accurate reading

[WSM]

I am rather sad right now.

i just weighed out the dried chlorate and my estimate was far off. i had exactly 101g of chlorate precipitating out of my cell, which brings my CE to about 30% or so if i include the chlorate still in solution.

as i said before. next batch i will record everything to get a more accurate reading

 

Was this run a first run from salt water or was it run from recharged mother liquor? A great deal of energy is used just getting the mother liquor created. Once generated and recharged with salt, things really pick up and a lot more chlorate is produced.

 

If this run was from a recharged cell, that is a poor yield indeed (27.6% not counting the chlorate still in solution).

 

The more data you observe and accurately record, the better equiped you'll be to analyse the results (plus the more we can help, being armed with good information).

 

By the way, when I first ran my glass pickle jar cell, I didn't record much of anything. I was just thrilled it worked and I wasn't kidding myself about turning saltwater into chlorate. Next I ran it enough to collect a good supply of crystals (a few kilos). THEN, I began to consider how to improve things. Now look where I am... (again, it's amazing how complex a simple idea can get!)

 

WSM

[oldmanbeefjerky]

what do you mean by recharged?

 

am i meant to keep the main liquor and add more chloride then just sieve out the chlorate at the end of each run? i can certainly see how that would improve results, or do you mean recharge by adding enough hydrochloric acid to replace all of the lost chloride? in which case i dont understand how that would help.

technically i havent even finished the run yet, i just removed the chlorate and replaced it with sufficient chloride which i dissolved in, because i had no room to fit the electrodes in which are secured to the lid of the jar, after it precipitated out when it cooled down as a result of being turned off.

 

though my run is nearing to an end. the current minimum is now 8.3, and once it hits 5 or 6 amps i will turn it off (starting current was 16-11A).

 

also, the salt is really starting to build up on my electrode plates, but is stopping right where i smeared the grease, looks like i wont really need to bother myself with tubular connections.

[WSM]

what do you mean by recharged?

am i meant to keep the main liquor and add more chloride then just sieve out the chlorate at the end of each run?

 

Yes, remove the chlorate crystals and recharge the cell with more chloride. If you have two jars, one can be dissolving new salt into the depleated liquor as the other one is running. By alternating the two you can keep a good supply going. If this isn't practical, then some other method can be devised to get new chloride into the depleated solution.

 

Be careful with salt build-up on the electrodes. A salt bridge between them can short out the system and damage the power supply . Perhaps you need a larger container to allow more fluid movement in your cell. Do you have the ability to photograph, or better yet, video the cell running? A few seconds of a clear view of the cell running will tell volumes about what's going on in there. Let us know.

 

WSM

[oldmanbeefjerky]

Yes, remove the chlorate crystals and recharge the cell with more chloride. If you have two jars, one can be dissolving new salt into the depleated liquor as the other one is running. By alternating the two you can keep a good supply going. If this isn't practical, then some other method can be devised to get new chloride into the depleated solution.

 

Be careful with salt build-up on the electrodes. A salt bridge between them can short out the system and damage the power supply . Perhaps you need a larger container to allow more fluid movement in your cell. Do you have the ability to photograph, or better yet, video the cell running? A few seconds of a clear view of the cell running will tell volumes about what's going on in there. Let us know.

 

WSM

 

Inroducing new chloride into the cell wont really be a problem for me. but tomorrow morning i will take a photo a few photo's at different angles of my cell running , the cell is only temporary. the permanent cell i will build in a week or so, once i have the pieces.

The salt build up im talking about is on the outside of the cell, not the inside.

[oldmanbeefjerky]

Here are some pictures ive taken. the amount of chlorate precipitating out at the cells high tempurature is about the same as last time and after the same amount of time. also the grease is still keeping the salt from rising any further as you can see in the photos.

Most of that salt on the base is actually just destroyed rubber which i had hoped would stand up agaisnt the chlorine but didnt. i cant remove it however.

 

 

Edited August 24, 2011 by oldmanbeefjerky

[Bonny]

Here are some pictures ive taken. the amount of chlorate precipitating out at the cells high tempurature is about the same as last time and after the same amount of time. also the grease is still keeping the salt from rising any further as you can see in the photos.

Most of that salt on the base is actually just destroyed rubber which i had hoped would stand up agaisnt the chlorine but didnt. i cant remove it however.

 

That's not a cell, that's a baby toy...

 

I'm just kidding, good start. As WSM noted, you'll get much more chlorate on the next batch(es) using the recharged cell liquor.

[WSM]

That's not a cell, that's a baby toy...

I'm just kidding, good start. As WSM noted, you'll get much more chlorate on the next batch(es) using the recharged cell liquor.

 

A larger cell for those (huge) electrodes isn't a bad idea. If you can place the electrodes lower in a larger cell, a convection-like current can develop (helped by "hydrogen lift") to keep the fluid stirred up and the heat evenly distributed. Just don't let the electrodes reach to the bottom of the cell where the crystals go and salt bridging is possible (shorting the electrodes is a BAD thing).

 

So dissolve more salt in there and run it again !

 

WSM

[frank]

Perhaps one reason for the low current efficiency is that your anode current density is very low. You give dimensions of your anode above somewhere and it was quite big. The amount of current that anode would be capable of handling is quite large, much more that you are sending into it anyways.

Run the Anode at about 0.2 of an amp for every square cm of anode surface that you have. If cell heats up too much put the whole lot sitting into a large container of water.

Forget about power efficiency as it matters little. It's only going to cost a few bob extra if you are wasting power. The power supply will probably be wasting more power that the cell.

Current efficiency is more related to 'time' efficiency. The more chlorate in a given time the better.

Read up on current efficiency. Current efficiency has to do with the ratio of (total amount of electrons that have entered the cell) to (the amount of product you have managed to produce). It's hard to calculate CE when the current is varying thoughout the run. Thats the beauty of a constant current going into the cell.

 

How many times you should add acid to a cell when controlling pH is something that has come up before in various places. Once a day is too little in my opinion. It's not that it 'will not work'. It's better than only doing it once every two days (pretty shitty) but it' not often enough. The pH will have drifted upwards in the 24 hours and will be somewhere in the (rough guess) region of 8 or 9. I am inclined to think that a minimum of four times a day would be getting acceptable. If you have a system set up with a timer and pump or solenoid you might as well do it every hour or so (24 times a day).

Also (with the once per day approach) apart from the fact that the pH will have drifted upwards to 8 or 9 you are faced with the problem of adding quite a lot of acid to the cell in one go ((one days supply), as opposed to (one days supply)/24)). Big dirty blast of Chlorine out of cell as you add acid.

 

How close are the cathodes of the bottom of the cell? If they are only going down half way there will be a large quantity of liquid not taking part in the cell. It will be sitting at the bottom stone cold with the top only circulating (as said by WSM above). It's hard to tell from the picture how low the cathodes go.

Put your hand on the side of the cell when it's running as see if the bottom is cold and the top warm.

The solid chlorate will not short the electrodes even it is is touching both. It' not conducting in itself and a mixture of solid chlorate + electrolyte will not short out electrodes. A large quantity of solid blocking circulation of electrolyte around the electrodes will interfere with cell operation.

 

Frank

Edited August 25, 2011 by frank

[WSM]

Perhaps one reason for the low current efficiency is that your anode current density is very low. You give dimensions of your anode above somewhere and it was quite big. The amount of current that anode would be capable of handling is quite large, much more that you are sending into it anyways.

Run the Anode at about 0.2 of an amp for every square cm of anode surface that you have. If cell heats up too much put the whole lot sitting into a large container of water.

Forget about power efficiency as it matters little. It's only going to cost a few bob extra if you are wasting power. The power supply will probably be wasting more power that the cell.

Current efficiency is more related to 'time' efficiency. The more chlorate in a given time the better.

Read up on current efficiency. Current efficiency has to do with the ratio of (total amount of electrons that have entered the cell) to (the amount of product you have managed to produce). It's hard to calculate CE when the current is varying thoughout the run. Thats the beauty of a constant current going into the cell.

 

How many times you should add acid to a cell when controlling pH is something that has come up before in various places. Once a day is too little in my opinion. It's not that it 'will not work'. It's better than only doing it once every two days (pretty shitty) but it' not often enough. The pH will have drifted upwards in the 24 hours and will be somewhere in the (rough guess) region of 8 or 9. I am inclined to think that a minimum of four times a day would be getting acceptable. If you have a system set up with a timer and pump or solenoid you might as well do it every hour or so (24 times a day).

Also (with the once per day approach) apart from the fact that the pH will have drifted upwards to 8 or 9 you are faced with the problem of adding quite a lot of acid to the cell in one go ((one days supply), as opposed to (one days supply)/24)). Big dirty blast of Chlorine out of cell as you add acid.

 

Frank

 

I plan on hourly additions of dilute acid since I'm mimmicking Swede's pH control method. I feel 4 times a day would be a reasonable minimum, but more times is better (but not more than once an hour). The high accuracy digital timer Swede recommended allows a metered amount hourly for as long as you wish to run it (down to a hundredth of a second!).

 

As for CE, doesn't it average or do you get a curve as it runs? If you meter the Watt/hours of the total run and weigh the dried product, you should be able to get a fairly accurate calculation, no?

 

WSM

[patsroom]

So many things would be clear and understood if a person would read the four (4) areas that are about everything we have talked about for the past few pages. I beleive that number one pages to read would be all of Swede's Blog. And secound one would be about the Chlorate Cell in Random Chats as well as all of this forum and maybe Let's take this outside in the Random Chats. But for any of this to be fully understood you would need to read from start to finish, then as you read take notes. I do it and if I am not mistaken so does WSM and Swede was always refering to his notes too!

As I can only speak for my self- I stand not on the ground but on the shoulders of those who came before me- Swede was of the best. His work was shared so that we all could learn as he grew with his knowledge. I know I would not be as far as soon as I have if it were not from Swede.

Pat