making potassium (per) chlorate

[WSM]

heres what ive learned within the last 20 pages, mostly answered from swedes blogs

1. that question is unanswerable , we need to know how much chloride will be in the cell, and wheather or not you are using PH control. the best i can tell you is that it took me roughly 60-80 hours to make 400g of chlorate from 320g chloride, at an average of abount 14A, in a 2.6L cell., using no ph control.

A bigger cell with more chloride would work much faster, a large bucket cell ive heard here and there, can make about a quater-half a kilo per day running at about 30-45A

2.MMO is about the best, consiering potential value for money. at cheapest you will be paying about $20 for an anode if you buy online, and thats considering that I am the cheapest (on ebay anyway for an anode ready to use ,anyway). there are other people that sell anode sheet without connections, for about $20, which can potentially make about 250-1000g per day, but dont take my word on that. I cant really answer the other part of your question, sorry.

MMO anodes can be sent in regular letters, so you should widen your search to global, because shipping shouldnt be much of of a problem.

3. Platinum is a good substitute for MMO, but then again isnt. Another which works, OK is manganese dioxide and cobalt oxide, but its use is limited, though it isnt that hard to fix up if you have a bit of nitric acid and/or cobalt nitrate manganese nitrate / oxides, necessary to thicken it up.

Graphite can be used, but it is tricky. ive heard graphite can make chlorate rather efficiently, making about 80g of chlorate per 1g of graphite lost, and considering you can get sausage thick graphite rods about $7ea which are roughly 300-400mm thick at the right wholesalers, its an option, but not a very good one, considering MMO lasts much longer.

4. potassium dichromate helps protect any Iron in solution from eroding, and perhaps helps preserve MMO, but is more useful in continuous cells where the dichromate never really leaves the cell. I did a quick search and found dichromate is a tad expensive.

5. you mean lead dioxide, and they are generally used for making perchlorate, not chlorate, so yes, in that sense they are better, but for chlorate, they are not.

 

Well, yes and no. I always thought MMO was a good substitute for platinum, if your goal is chlorate production. I'm thinking platinum is a Mercedes Benz and MMO is a Ford. Both will get you there but the difference is the cost.

 

WSM

Edited October 17, 2011 by WSM

[Mumbles]

I had a thought on pH control. Do you think that using a buffered electrolyte solution might help to reduce the need to manually adjust the pH? You could probably arrange something to where you may only have to adjust it maybe once a day, and not really have to worry much about it precipitating out with cooling. I'm not sure if you arrange something that is both electrolytically inert and will not contaminate your product too bad.

[pdfbq]

With a more efficient system and electrode spacing, plus in a larger volume cell; I believe the cell can produce over 500g a day; and more with pH control plus using less electrical energy in the process. I believe dichromate use will provide a marginal improvement in efficiency but I choose not to use it so I don't have to deal with the envionmental issues (and yes, it is a carcinogen and mutogenic compound, as well as having a caustic and corrosive effect on tissues; truly nasty stuff). If you don't have to use it, don't.

 

This is my opinion anyway.

 

WSM

This would mean my cell would be at 25% efficiency when the 500g per day cell would be at 100% wich i.m.h.o. is impossilble which means my cell must run at 20% or less. This I do not believe

I believe with the simple approach you can have about 40~50% efficiency.

[WSM]

This would mean my cell would be at 25% efficiency when the 500g per day cell would be at 100% wich i.m.h.o. is impossilble which means my cell must run at 20% or less. This I do not believe

I believe with the simple approach you can have about 40~50% efficiency.

 

There's not enough information presented to make any accurate CE determination. If properly set up, I expect your CE to be between 45% and 60%. If other factors were attended to (pH control plus myriad other little details), your CE could be between 80% and 95%. Nobody gets 100%, even in industry; it just doesn't happen. The Holy Grail for amateurs is breaking 90% CE. Anything approaching this is admirable.

 

The first run of any cell is not the one to judge your CE on. The second or third run will better determine how well things are running. The first run develops the liquor and most of the energy input is used for that purpose. After that things settle, conditions stabilize and additional salt in and yield of oxidizer are more quantifiable, so CE (current efficiency) can more accurately be determined.

 

WSM

Edited October 18, 2011 by WSM

[WSM]

This would mean my cell would be at 25% efficiency when the 500g per day cell would be at 100% wich i.m.h.o. is impossilble which means my cell must run at 20% or less. This I do not believe

I believe with the simple approach you can have about 40~50% efficiency.

 

One more thought... If you can't buy chlorate where you live for any amount of money, does any of this matter? The main point is getting the oxidizers needed to make your fireworks or rockets. If this is your only option and it works, who cares about the cost and effort to achieve it?!

 

With my first successful cell using CP titanium and MMO electrodes, I didn't give any thought to efficiency or expence. I was just thrilled it worked. It was after making many runs and several kilos of KClO₃ that I began to consider improvements and efficiency as well as cost.

 

WSM

[WSM]

I had a thought on pH control. Do you think that using a buffered electrolyte solution might help to reduce the need to manually adjust the pH? You could probably arrange something to where you may only have to adjust it maybe once a day, and not really have to worry much about it precipitating out with cooling. I'm not sure if you arrange something that is both electrolytically inert and will not contaminate your product too bad.

 

Thats an interesting thought. Any suggestions?

 

It may depend on the cost and efficacy of the suggested buffer, as well as availability and other factors. The pH control with dilute pool acid fills the bill quite well and (after the initial outlay for equipment) is easy and inexpensive. Judicious purchasing of essential equipment on eBay can lower the total cost of the acid system to a small fraction of the expense of a commercial unit. Of course the system must be well-built to prevent leaks or other problems.

 

WSM

[Mumbles]

The first two that came to mind were phosphate buffer and acetate buffer, using potassium instead of the standard sodium of course. The acetate buffer should be able to be held closer to the ideal pH, and should be easier to clean up. Both acetic acid and potassium acetate should wash away cleanly with the cold water rinse. Acetic acid is fully oxidized, so in theory it should be relatively inert in the oxidizing environment, but honestly I don't know. Additionally, acetic acid is weaker than chloric acid so it wont form any unstable explosive acids, though this is pretty much a requirement for any buffer, so it's kind of a non-point.

 

This would be a worry of mine: http://en.wikipedia.org/wiki/Kolbe_electrolysis At least the by-products will remove themselves from the system.

[WSM]

The first two that came to mind were phosphate buffer and acetate buffer, using potassium instead of the standard sodium of course. The acetate buffer should be able to be held closer to the ideal pH, and should be easier to clean up. Both acetic acid and potassium acetate should wash away cleanly with the cold water rinse. Acetic acid is fully oxidized, so in theory it should be relatively inert in the oxidizing environment, but honestly I don't know. Additionally, acetic acid is weaker than chloric acid so it wont form any unstable explosive acids, though this is pretty much a requirement for any buffer, so it's kind of a non-point.

This would be a worry of mine: http://en.wikipedia....be_electrolysis At least the by-products will remove themselves from the system.

 

Well, Mumbles, that's an interesting concept. I don't know how it would play out in practice, but the theory sounds intrigueing. The amazing multitude of active species in a working cell may or may not allow the buffer to function as designed. Hopefully the desired reactions would take place and the undesirable ones would not, but there are a lot of variables in play here.

 

The most beautiful (simple) method employs only things that are already in there, or aren't foreign in any respect, so no new variables are added to the soup. That is the beauty of HCl addition; H⁺ and Cl^- are already in there, we're just boosting their parts to offset the tendency of the reactions to run to the alkaline and add steps which use current in a wasteful way. HCl is also readily available and inexpensive, as well as nearly ready-to-use (simple dilution is the only preparation required).

 

I'm inclined to continue to pursue the course I'm already on, but I'll keep an open mind about the buffering option. Let us know if you decide to experiment with it, and the results. In fact, if you need assistance or material support for the effort, I'd be happy to contribute to the cause. I have materials on hand that would make an experimental test cell to use for the effort. Let me know.

 

WSM

[pyrojig]

Yes do keep us posted Mumbles if you have success on the alternate buffering option... It too find that HCl is a great and cheap source of a buffer . It is available at most all hardwares and a gallon lasts quite some time ( if your sys is under 50gal )

 

Well, Mumbles, that's an interesting concept. I don't know how it would play out in practice, but the theory sounds intrigueing. The amazing multitude of active species in a working cell may or may not allow the buffer to function as designed. Hopefully the desired reactions would take place and the undesirable ones would not, but there are a lot of variables in play here.

 

The most beautiful (simple) method employs only things that are already in there, or aren't foreign in any respect, so no new variables are added to the soup. That is the beauty of HCl addition; H⁺ and Cl^- are already in there, we're just boosting their parts to offset the tendency of the reactions to run to the alkaline and add steps which use current in a wasteful way. HCl is also readily available and inexpensive, as well as nearly ready-to-use (simple dilution is the only preparation required).

 

I'm inclined to continue to pursue the course I'm already on, but I'll keep an open mind about the buffering option. Let us know if you decide to experiment with it, and the results. In fact, if you need assistance or material support for the effort, I'd be happy to contribute to the cause. I have materials on hand that would make an experimental test cell to use for the effort. Let me know.

 

WSM

[Mumbles]

The idea came up while thinking about pH control. It's not so much of a cost as it is a convenience issue. Swede and others have developed great ideas for pH control. The issue I was thinking about in my head was the frequency of adjustment. There are clearly several continuous, or relatively frequent dosing options, which is probably ideal. The less often you adjust the pH, the greater the change must be. If you're adding it only once a day, you're likely to get a cloud of chlorine gas. I was thinking of ways one may be able to get away with less manual adjustments, though it may not adjust any chlorine production. The more I think about it, the less viable it probably is. I can't come up with anything that would be inert in the reaction environment. Bleach or hypochlorous acid will react with most anything. The products may be innocuous, but could "eat up" that intermediate reagent. It'd form things like pyrophosphates or peracetates. Unfortunately all the pyros and pers in there may not be beneficial.

[WSM]

The idea came up while thinking about pH control. It's not so much of a cost as it is a convenience issue. Swede and others have developed great ideas for pH control. The issue I was thinking about in my head was the frequency of adjustment. There are clearly several continuous, or relatively frequent dosing options, which is probably ideal. The less often you adjust the pH, the greater the change must be. If you're adding it only once a day, you're likely to get a cloud of chlorine gas. I was thinking of ways one may be able to get away with less manual adjustments, though it may not adjust any chlorine production. The more I think about it, the less viable it probably is. I can't come up with anything that would be inert in the reaction environment. Bleach or hypochlorous acid will react with most anything. The products may be innocuous, but could "eat up" that intermediate reagent. It'd form things like pyrophosphates or peracetates. Unfortunately all the pyros and pers in there may not be beneficial.

 

Thanks for devoting the time and thought to the problem. The simplest method to adjust pH levels is with active pH control. Unfortunately, even though pH controllers are available, the cell environement "poisons" the (expensive) probe used to monitor the pH levels. Without an elaborate means of protecting the probe or prolonging its life, active pH control is impractical. Fortunately, Swede and others have determined that there is a direct correlation between the current used and the required amount of HCl (of known concentration) to use to achieve the higher efficiency sought. I will share that formula later after I cover a safety point.

 

The first time in recent history I added a squirt of pool acid to an active cell, I nearly gassed myself. As soon as the acid hit the cell liquid a greenish yellow puff of chlorine gas formed. Fortunately, it was very little and I avoided getting much, but it was a sobering moment. I quickly realized I needed a better way to handle this. I believe Swede had a similar experience and came up with a system to handle the problem. In his blogs he mentions adding a PVC pipe with cross holes situated below the liquid level in the cell from the cell lid. What he does is add measured amounts of dilute acid into the diffuser tube where the acid mixes with a small amount of the liquor and slowly diffuses into the rest of the cell. This keeps most of the chlorine in solution where it creates the desired chemical species levels needed to reduce the power required to turn KCl to KClO₃ (using 6 moles of electrons per mole of chlorate instead of 9 moles without pH control) so less electrical power is required to produce more chlorate in a shorter time.

 

The formula Swede learned from his study and what he shared with me is:

 

0.057 ml of concentrated (32%) HCl per ampere, per hour, with the HCl delivery volume cut by 33% after the chlorate crystals begin to form.

 

To apply this to our system we need an accurate measurement of the current (Amperes or Amps) used by the cell. A DC ammeter (digital or analog) connected between the power supply and the cell will give us this measurement. Knowing the current demand of our cell we can determine how much acid to add to the system. If we have the equipment we can either pump acid into the cell or use a gravity feed system as Swede did (see his later blogs). It took me a long time to collect the required components but I plan to try the gravity fed system (even though I have the compatible equipment to pump the acid).

 

The thing to do is determine exactly how much liquid our acid system delivers in a period of time. First, we need an accurate and precise electronically controlled timer. Swede comes to the rescue in his blogs with a highly accurate digital timer for less than $40 and shows how to set it up in a project box. The thing is infinitely variable between 10ms and many years (seriously!), and can be set up to cycle hourly and reset itself for continuous operation...perfect! Next, we need compatible valving to convert the timer signal to physically moving a metered amount of acid to the cell. I searched and eBay fills the bill and is where I found similar miniature PFTE solenoid valves to what Swede used for about $22 delivered. The tougher find was the PTFE needle valve to accurately control the feed rate of the acid. I was extremely lucky to find the same model Swede used for a fraction of what he paid. I plumbed all the valving together with compatible tubing and PVDF fittings and when I develop a reservoir tank for the acid, I'll test the volume delivery rate with water into a graduated cylinder and fine tune it for use with the cell.

 

Once the timer and valving are ready we need to find out how much acid is required. Then we'll know what to set our timer duration cycle to. Using the formula Swede gave I realize it is based on concentrated acid. Since I want to use diluted acid, I need to increase the fluid flow to deliver the same weight of acid to achieve the correct pH level. Say I have a system that runs at 50 Amps to start and I'm using acid diluted to 8% (1/4 the original concentration). according to the formula we need 11.4 ml of our dilute acid per hour to maintain the desired pH to START and about 7.6 ml per hour after crystals start to form. The acid added represents 50 times the 0.057ml times 4 to offset the amount of dilution. The added water to our system doesn't hurt since the process consumes water and even more is required as things run.

 

Once all the gear is arranged and the system running, pH control is trivial; but getting there was the challenge. Constant monitoring is still required till everything stabilizes and adjustments should be made as current drops. I believe a continuous system will reach a balance and the acid requirement will stabilize. Then only occasional rate adjustments may be required, if at all. We'll see...

 

WSM

Edited October 18, 2011 by WSM

[WSM]

I believe with all the electronic measuring and control equipment Swede was working with, he was well on the way to having a fully pH controlled system based on accurate digital measurement of the current demand of his system and automated periodic acid injection on the fly. Whether he completed any such system or is even currently active in any such pursuit, we can't know; but that he was headed that way, the blogs show every indication he had the skill set, experience and equipment to do so.

 

Too bad he's not posting here anymore. It was amazing to see how far he had come and how fast.

 

WSM

[Arthur]

While the mathematical approach may be nice, the practical approach seems to favour running the cell for an hour then titrating back to original pH then adding that much every hour. With a less concentrated acid it may be possible to use either a bellows pump or a peristaltic pump on two timers -every hour(ish) the pump runs for so many seconds.

 

http://www.iwakipumpsltd.co.uk/products.php and look at the KB range - it's a bellows pump of selectable stroke and time period. Someone in the USA please look for redundant film processing machinery. A professional E6 machine should have about 20 replenishment pumps, and process E6 is fading into obscurity with the advent of digital so the machines are being scrapped and there may be salvage to be had.

 

Added; This seller may direct you to replenishment pumps salvage in the USA, durst-pro-usa on ebay

Edited October 18, 2011 by Arthur

[WSM]

While the mathematical approach may be nice, the practical approach seems to favour running the cell for an hour then titrating back to original pH then adding that much every hour. With a less concentrated acid it may be possible to use either a bellows pump or a peristaltic pump on two timers -every hour(ish) the pump runs for so many seconds.

http://www.iwakipump...uk/products.php and look at the KB range - it's a bellows pump of selectable stroke and time period. Someone in the USA please look for redundant film processing machinery. A professional E6 machine should have about 20 replenishment pumps, and process E6 is fading into obscurity with the advent of digital so the machines are being scrapped and there may be salvage to be had.

Added; This seller may direct you to replenishment pumps salvage in the USA, durst-pro-usa on ebay

 

Hi Arthur,

 

This approach may work with a conditioned cell, but the first run when you're turning the salt solution into mother liquor (hypochlorite, etc.) wouldn't be the same as when running a recharged cell after the initial run. Yours sounds like a reasonable approach, though. I like it. (and I can finally get around to using that pair of titration columns gathering dust in the shop!)

 

I do have peristaltic pumps and metering pumps I can use. I wanted to try the gravity-fed system first, though. I imagine it will be the most economical to run.

 

I did find a source for the Iwaki KB type bellows pumps from a surplus source. I'm waiting for a return message from the seller before I commit to getting any. Thanks for the heads-up.

 

WSM

[Arthur]

As any fresh solution you would need to develop a method of getting to a reliable process control. So if you start the cell on a morning then with checks at increasing intervals during the day to establish the addition rate then by evening the addition rate should be estimatable for the night, corrections being made next morning. Still, keeping the CE in the 90% range will allow savings in energy cost over letting the efficiency drop off with non-optimal pH

 

With something like the Iwaki pumps it will be easy to make additions in the order of 10ml and these can be every minute or half hour. Usually one allows a small shortfall on additions and adds the rest to analysis periodically.

 

Once the cell has matured then another pump could add brine and displace product loaded solution to a crystalliser.

[oldmanbeefjerky]

Ive been thinking,

what about rather than using hydrochloric acid in liquid form, why not use it in gas form?

 

A small vaporizer or light heat pad could feed a steady supply of hydrochloric acid gas, through a one way valve, and into a bubbler tube already supplying air into the cell ( to churn up the cell liquor ).

The specifics are still cloudy to me, im ill and unable to think properly.

But you understand what im saying?

A steady slow input of hydrochloric acid over a large amount of time roughly matching its consumption in the cell, according to the average amperage.

[WSM]

As any fresh solution you would need to develop a method of getting to a reliable process control. So if you start the cell on a morning then with checks at increasing intervals during the day to establish the addition rate then by evening the addition rate should be estimatable for the night, corrections being made next morning. Still, keeping the CE in the 90% range will allow savings in energy cost over letting the efficiency drop off with non-optimal pH

With something like the Iwaki pumps it will be easy to make additions in the order of 10ml and these can be every minute or half hour. Usually one allows a small shortfall on additions and adds the rest to analysis periodically.

Once the cell has matured then another pump could add brine and displace product loaded solution to a crystalliser.

 

It sounds like a lot of hands-on maintenance.

 

Swede's "rule-of-thumb" method seems less involved to me. I haven't tried it yet but plan to when I run the "experimental cell", since I've already geared up to do so. I really appreciate the information about the Iwaki pumps, though. I'll see if I can get some and try them out.

 

WSM

[WSM]

Ive been thinking,

what about rather than using hydrochloric acid in liquid form, why not use it in gas form?

A small vaporizer or light heat pad could feed a steady supply of hydrochloric acid gas, through a one way valve, and into a bubbler tube already supplying air into the cell ( to churn up the cell liquor ).

The specifics are still cloudy to me, im ill and unable to think properly.

But you understand what im saying?

A steady slow input of hydrochloric acid over a large amount of time roughly matching its consumption in the cell, according to the average amperage.

 

Perhaps in industry the addition of dry HCl from gas bottles is how it's done; but on a small hobbiest scale it seems impractical. I can easily obtain HCl pool acid at a pool supply house or even the Big Box Home Center. If I had the connections to buy from a chemical supplier, I'd already be asking about bulk KCl instead of getting it as water softener salt.

 

Wait, I misunderstood you. You mean to generate HCl gas from the liquid acid and then feed that gas into the cell liquid? I don't see the advantage. Handling the gas is trickier than handling the liquid acid. At least with the liquid acid, One can more easily quantify the dose. Besides, the system needs water repleshment anyway. It's an interesting thought, OMBJ; but not particularly easy to control (let alone that it's potentially hazardous). Keep thinking, though; it never hurts to consider all the options...

 

I hope you get well soon.

 

WSM

[Arthur]

Handling HCl gas has to be a very unfriendly task for amateur chemists, it's all to likely to kill plants or strip paint at home if it gets out.

 

Iwaki is only one maker of photo lab replenishment pumps, others exist and may be available second user. On the Iwaki models the pump stroke is variable and there are several sizes of bellows, then you can adjust the run and pause (mark space) ratios to get a huge range of delivery volumes. IMO the first day would be spent tracking the cell maturing then fine tuning the HCl(aq) addition for long term running. In a mature continuous cell then continuous operation should be possible with little supervision of the pH while maintaining a good cell efficiency.

[oldmanbeefjerky]

What i meant was slowly including HCl as a gas, in the same way you would drip it into the cell, at a constant rate.

Ive been thinking about this because it would be easier for me to do than use a pump to add the acid in liquid form periodically. plus, since my cell will be only about 4-6L, i wont really need much acid, plus refilling the acid being vapourized can be done once every few days as opposed to the alternative which is squirting a few mL's in every 6 hours or so.

I dont see it as dangerous, plus i am already going to scrub the gas escaping the cell anyway.

It will be like at most 50ml of acid being evapourated at a time

and in total i wont use more than the cell will ever use in a single batch.

 

 

-edit-

Its just that i see too much going wrong with using timed pumps which i by the way cannot find as well as just handling the HCl as a liquid in general really.

Besides, vaporizing it rids me of any unwanted contaminants inside the acid, which there are quite a lot of in the only HCl that i can get my hands on.

Edited October 21, 2011 by oldmanbeefjerky

[WSM]

What i meant was slowly including HCl as a gas, in the same way you would drip it into the cell, at a constant rate.

Ive been thinking about this because it would be easier for me to do than use a pump to add the acid in liquid form periodically. plus, since my cell will be only about 4-6L, i wont really need much acid, plus refilling the acid being vapourized can be done once every few days as opposed to the alternative which is squirting a few mL's in every 6 hours or so.

I dont see it as dangerous, plus i am already going to scrub the gas escaping the cell anyway.

It will be like at most 50ml of acid being evapourated at a time

and in total i wont use more than the cell will ever use in a single batch.

-edit-

Its just that i see too much going wrong with using timed pumps which i by the way cannot find as well as just handling the HCl as a liquid in general really.

Besides, vaporizing it rids me of any unwanted contaminants inside the acid, which there are quite a lot of in the only HCl that i can get my hands on.

 

If done the way Swede recommended, the liquid acid isn't pumped, but gravity fed from a resevoir about one meter or less above the cell. It's still using a precision digital timer, but rather than actuating a pump, it's opening a solenoid operated Teflon valve which feeds the acid through a Teflon needle valve for accurate addition of the acid into the cell solution.

 

In my opinion, It'll be much easier to get accurate pH control with the liquid acid solution than with gaseous HCl, especially if generated from impure liquid acid. If I'm proven wrong in this opinion, I'll be the first to admit it, but I don't see how the non-bottled, unpressurized gas would be able to be effectively applied to accurately control the pH of the system. If tried, I hope it will be safely contained so no injury or damage to persons or property results.

 

Also, if you try this method; do keep good notes and share your results. Please keep it safe, also.

 

WSM

[oldmanbeefjerky]

No need, ill admit that it wont be precise, but Ph control to some degree, although not perfect, should improve the CE and yield!

Its all i can do right now with what i have. And obviously its better to have non precise Ph control than none at all.

But i hear you loud and clear, ill be sure to deal with the excess HCl gas to avoid certain doom to all biological life in the general area

[Verge]

So I just finished reading the first 5 pages of this topic and I was wondering if pbo2 ever got phased out because making them is actually pretty simple.

http://www.physicsforums.com/showthread.php?t=253519

Scroll down to production http://en.wikipedia.org/wiki/Lead_dioxide

[WSM]

So I just finished reading the first 5 pages of this topic and I was wondering if pbo2 ever got phased out because making them is actually pretty simple.

http://www.physicsfo...ad.php?t=253519

Scroll down to production http://en.wikipedia....ki/Lead_dioxide

 

The simple lead-acid battery method of making lead dioxide makes the porous alpha form and not the desireable crystalline beta form of LD. If we can get the beta form, then we'll have something.

 

WSM

[Mumbles]

As I understand it lead dioxide electrodes are easy to produce, but not all that easy to produce well. It's unclear what causes the issues, as you have stated, it's not a particularly difficult procedure. To make good lead dioxide electrodes the general procedure is to electrolyze a titanium or platinized titanium substrate from a solution containing copper and lead nitrates. The pH is controlled with a mixture of the respective carbonates. There is some use of surfactants as well that is largely proprietary to the companies that make them.

 

I really don't know if it's the surfactants, stability of the power source, phase of the moon, or what that really makes this less trivial than it should be.