noob question on chlorate cell

[nish]

good job guys

 

Turning the adjustment pot on the led power supply from 5V to 4.1 volt got the thing working =)

It's running at 4.7V @22.1A

Edited May 15, 2017 by nish

[MrB]

What is the size of your anode? It's a bit of guessing from the pictures, but if the higher current does increase the wear on the PT anode, then you might be a bit on the high end. I think i read "about" 300mA/cm2 to be the sweet spot.

 

And turning down the voltage on the powersupply should decrease the current, so it should have been running on it all along, just to hot, and to high current.

 

I suppose having a large spacing between the anode and cathodes is good in the way that the salts should fall away easily, and while voltage seams a bit high for chlorate production... I don't know, if it works, and you are happy, go for it.

[nish]

Krohn Platinized Titanium Anode 2" x 3" after warming up,power supply now its now running at 4v @ 28A and power supply is unstable again

 

I have the voltage pot turned all the way down, maybe I can change out the trim pot or use that power resistor I already bought.

 

so I should be running it at 11.6A to keep the anode life good.

 

 

 

The power supply was at overload earlier and would not stay on, not even for a second, that was the problem i was having earlier :$

what's the recommended voltage for chlorate production? how does it effect making Kclo3 in short?

 

 

 

Thanks btw this info saves me time and money from accidentally frying my anode etc

Edited May 15, 2017 by nish

[nish]

Samples of know substances dissolved in hot water then cooled to refrigerator temp.

Kcl is still a clear 100% liquid (left)

Kclo_{3 (middle)} & kclo_{4 (right) ;} most of it has mostly dropped out of solution

I guess this is how people go about separating it from kcl more or less lol

 

Edited May 15, 2017 by nish

[Mumbles]

The fact that you didn't get a precipitate from potassium chloride just means you didn't dissolve enough to begin with. 34g/100mL water will dissolve at 20C, and 56g/100mL with dissolve at 100C. Recrystallization is a good way to purify potassium chlorate though. Potassium chlorate has a similar solubility at 100C, but drops off drastically as it cools down to around 7g/100mL at 20C. Both have even lower solubilities at fridge temperatures.

 

It is my understanding that ripple is worse for Pt electrodes than something like graphite or lead dioxide. I don't know what level is acceptable, but the electrolysis literature has probably investigated it at some point. Someone like WSM may have better insight as well, being much more well versed on the subject than I am.

[nish]

Kcl was from the premixed solution used in the cell, max amount dissolved & stable at room temperature like MadMat suggested,(the solution was heated then let cool down) I stuck the tube in the freezer and a similar amount of crystals precipitated out

[MadMat]

Lloyd, I found some of my old literature on plating. The maximum allowed ripple for chrome plating is 5%. Just in case your interested.

[lloyd]

Mat,

I am! Thanks! Five percent is a LOT of ripple for a modern power supply. A decent (even Chinese) computer supply should be running somewhere around 1-2%.

 

Lloyd

[Arthur]

A modern DC psu should be much better than 5%, but a simple transformer and rectifier ( battery charger!) will be much more than that. Early chlorate plants used six phase motor generator sets to allow rectification to a low ripple DC. Significant ripple causes significant erosion of the platinum electrodes.

[nish]

Just a follow up /summery of my project so far:

 

parts: LED power supply 5V @ 70A $35; make sure to look inside for the switch and select 110 or 220V oops lol add large capacitor for voltage smoothing the bigger the better. TI square rod x2, Ti mesh x2 heavy gauge silicon wire and steel clamps; not copper. use adjustment pot to reduce voltage if PSU is overloaded; power resistor not desirable.

 

 

 

Changes Made:

 

*Higher temperature inside electrolysis cell seems to be required or all that is made is a clorox like stuff*;

cell reached 79C at one point

 

*~8g NaF was added*

*total cathode area increased to 4x anode area*

 

*Anode spot welded to larger conductor to reduce lid melt problem*

*vent Cl --> ptfe tube pending*

 

I use a scrap piece of the TI and spot welded to anode; at high amperage the lid can melt, also the square hole seals up better. (black ultra silicon) Cut holes in lid of Gama seal screw on lid top with heated blade of utility knife. I ran cell at high amperage / temp of 79C at one point; this is probably not ideal but some amount of heat seems to be required. Beware Chlorine gas, it really messes with your eyes, consider putting everything on a steel drum outside and vent Cl out of container; cover with super heavy duty construction garbage bag in inclement weather. I also included a temperature controller and probe tube made from C-pvc filled with mineral oil (to reduce the changes of things melting down if unsupervised ).

 

 

After changes made, one day later product could be seen on bottom of 5 gallon bucket, and water was cloudy now, not clear

 

 

 

[MrB]

Square bar?

I suppose it's easier to drill and such, but round stock lets you use regular compression fittings for the lid, rather then glue. Compression fittings should be possible to find in grades that are largely unaffected by the fluids, and salt.Pretty much has to be slotted, drilled, and then you can bolt the mesh to it, or spot-welded. (most opt for spot-welding if what i've read is correct.) Not sure if i think that is the best bet in the long run. Slotting, drilling, and then just unscrew the Ti bolting bits when you need to replace the mesh, rather then making a whole new anode. But harder, and a larger first investment.

 

Temperature is always a debatable area. Some say the higher the better, others say over temp X is to hot. X being dependent on what anode they are using. Some heat is absolutely necessary it seams.

If it works for you, and you don't burn through anodes. Go with it.

[nish]

Cool =)

 

Would you happen to have the specifics on the Ti tube & type of compression fittings, I'm not very familiar with plumbing fittings myself.

I found that they should be made from "PVDF (or Kynar)" and the Ti tube should be filled with lead free Tin solder and taped for attaching a ring terminal connector

 

Any recommended suppliers for Ti Pb anode? I looked on alibaba but sellers really stick it to you on shipping fees on alibaba for some reason.

[MrB]

I'd go with a solid rod. Just match the size of fitting and rod. WSM made a pretty detailed blogpost including the problems he had closing of one end, trying to seal it, and then cast tin in it. It really wants to crack.

 

eBay has some every now and then, but Ali is probably the best solution regardless of shipping. The idea is, list an item for a low price, and get the profit on the shipping rather then the item it self. eBay was the same way, and to some extent, still is.

[nish]

Good to know, I was looking for Ti tubing lol

 

I found this guys webpage $30 http://store.theamateurchemist.com/lead-dioxide-anode-2-by-3-with-4-stem/ seems cheaper, think quality is ok / ever use this guys anode

[nish]

On the last couple days messing with it, I dumped in 2 bottles of peroxide to break down the hypochlorite.

The next day there were so many crystals I couldn't see the bottom of the container, I figured it was a good stopping point.

 

I plan on using a smaller container next time so maybe it will heat up faster / not need as much current to keep it working making chlorate instead undesirable reactions. I boiled the water a bit at a time and added more h2o2 to finish off most of the hypochlorite chlorine stuff / filtered it

Edited May 30, 2017 by nish

[Mumbles]

I'm curious why you think you need to destroy residual hypochlorite. Boiling the mixture will turn it into 1/3 molecule of chlorate and 2/3 molecule of chloride. Using hydrogen peroxide is rather wasteful and useless as it converts it all back into chloride eventually.

 

I know you don't want to, but I REALLY suggest reading the various chlorate and perchlorate threads in the Chemistry section, as well as Swede and WSM's blogs.

[lloyd]

Thank you Mumbles!

 

Per some 'prior requests', I bit my tongue! <grin>

 

Lloyd

[Arthur]

It's impossible to get a handle on all the intricacies of the electrochemistry of salt solutions without understanding the chemistry. Without experiment and practise it's impossible to convert "understanding" into a working production system.

 

The old geocities site was rehosted recently and linked on this site earlier this week. Swede's blog, WSM's articles, and the huge "making (per)chlorate" thread are essential reading. It's unlikely that anyone will spend hours with you to design your own system if you don't want to research existing literature first.

 

Adding peroxide will also add lots of water which is always the enemy as it makes precipitation less easy and less complete. You are not going to find pure peroxide it's too seriously difficult to handle.

Edited May 30, 2017 by Arthur

[lloyd]

And, Arthur, even at high concentrations, once it's released its oxygen, what's left is 18g/mole of water!

 

Lloyd

[nish]

I've read through these pages, and I found the reference for a way to remove hypochlorite using H2O2 somewhere on that site chlorates.exrockets.com

http://web.archive.org/web/20091026132303/http://geocities.com/CapeCanaveral/Campus/5361/chlorate/chlorate.html. http://www.pyrobin.com/files/perchlorate_1.pdf I also skimmed through the APC section you've referred a couple times, but it's mostly about how to make different anodes and specific situations. It's not a very simple start to finish beginners guide which is what I was attempting to compile in this post.

 

 

I personally do not like playing with bleach( yes I know there's no sodium so it's not technically bleach) and I'd rather get rid of it. Currently I'm adding h2o2, and boiling the additional volume of water away, I'm aware that it would change the solubility making the job harder if I increase the volume of water. Since I received the suggestion from the guy on fireworking to just boil it only 30min, and the similar message mirrored here I'll give that a try!

 

 

This is a Hobby for me; something fun. If I excelled at chemistry, I would go to work for Big Pharma and make some real money.

It's not like I'm paying anyone here, nor begging anyone here to interact with me Arthur, since I posted and received replies I have a better understanding, and maybe someone else that reads this will also have a better understanding for making their own chlorate cell from the things I did right, and the things that could have been done better.

 

Thanks,

-Nishan

[nish]

Arthur, I received a 200,000UF 12V cap; max surge 20v, I'm guessing that will smooth the ripple quite a bit I do listen to your views / opinions. -N

[MrB]

Thing is, unless you intend to run the cell once, and never again, your better of just scavenging what you can, what precipitates, and feed the rest back in to the cell, recharge it with salt, and start producing again. It's going to save you time, money, and hassle.

 

That said... What ever floats your boat, i guess.

[lloyd]

"Since I received the suggestion from the guy on fireworking to just boil it only 30min..."

-------------

Yeah, boy! THAT's the way to ensure you have EXACTLY the same salt concentration as before! Just boil for a pre-determined time, and it'll be perfect!

 

Just for grins... did you ever consider checking the specific-gravity, instead? Naw... didn't think so...

 

(Sorry Mumbles... I just couldn't contain myself! <grin>)

 

Lloyd

Edited May 31, 2017 by lloyd

[nish]

ok thanks MrB, that sounds easier, I'll give try that.

 

Given the info i'm not sure why adding the two bottles of H2O2 made any difference to the amount of crystals visible in the cell.

Maybe when I rebuilt (resoldered high amperage traces) on the power supply something changed that I didn't realise o.o

[nish]

I think he was saying if you boiled it for 30 minutes in that time the hypochlorite would change to a different form.

 

I'm guessing if I mark a line and add x ml of water back I should be good..... if not well its not going to make a world of difference to me.

 

 

If I had that mercury hydrometer handy maybe I would Lloyd