Sciencemadness Discussion Board - Ammonium perchlorate without DIY anodes?

Ammonium perchlorate without DIY anodes?

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greenlight - 7-10-2015 at 07:06

It should be Hydrogen coming from the vent tube in the cell.
I lead mine into a sodium hydroxide solution but never noticed any real bubbling.
What temperature is your cell running at?

I ran my 900ml cell for 100 hours total at 5 volt 20 amp and didn't notice any chlorate precipitating on the bottom for the first day or so.
The chlorine cell is normal and was present every time i opened my cell too.

ecos - 7-10-2015 at 14:17

Quote: Originally posted by greenlight

It should be Hydrogen coming from the vent tube in the cell.
I lead mine into a sodium hydroxide solution but never noticed any real bubbling.
What temperature is your cell running at?

I ran my 900ml cell for 100 hours total at 5 volt 20 amp and didn't notice any chlorate precipitating on the bottom for the first day or so.
The chlorine cell is normal and was present every time i opened my cell too.

Thanks Greenlight for your answer, I really appreciate it.

I checked my cell and it is hot but not sure about the temperature. I think it is around 40-60 degrees Celsius.

I use a PC power supply. I used the 5v terminal but noticed that the volts drops till 3.5v when it is connected to the cell. the current is 4A.
The power supply is capable to produce 20A on 5v but not sure why it drops down to 3.5v.

what kind of power supply do you use?

two days of running and there is no sign of any KClO3 in the bottom.

[Edited on 7-10-2015 by ecos]

greenlight - 7-10-2015 at 18:28

I never had a meter to see what voltage or amperage was running through the cell but mine did get hot to about 60 or 70 degrees. I had to use a water bath at times because it would have gone higher.
I used this power supply:

http://www.ebay.com/itm/S-100-5-Super-Stable-Power-supply-un...

Have you been running the cell non-stop or have you let it cool down to see if an chlorate precipitates when the temperature drops back down?

hyfalcon - 8-10-2015 at 02:23

If you are using potassium salts in a concentrated solution to start, you won't have to cool the electrolyte down. Due to it's lower solubility, the potassium chlorate starts falling out of solution on it's own.

greenlight - 8-10-2015 at 03:00

Yes, my cell precipitated chlorate after the first day but when I cooled it down to room temp even more fell out of the solution.
Is it possible that Ecos does have chlorate but so little at the moment that it is staying dissolved while he is running the cell because of the temperature of the electrolyte.

ecos - 8-10-2015 at 03:02

I didnt stop the cell to check the chlorate.
I only had power outage for several hours.would this destroy the chlorate formation?

I cant see any participation in the bottom of the cell and it is running for 3 days.

greenlight - 8-10-2015 at 03:20

That shouldn't make a difference as far as I know.
I ran my cell in 20 hour intervals with a 4 hour rest every day and had no problems.

Only difference was my cell was 900ml and I used MMO anode and Titanium cathode with 5 volt 20 amp power supply.
Maybe yours is taking longer to form chlorate because of lower current through the cell and you have a much larger cell (2.5L if I am correct).

ecos - 8-10-2015 at 06:24

I stopped the circuit now. it looks really ugly and very yellow.
I noticed a lot of yellow particles in the bottom of the cell. I identified they are metal because they could be attracted to magnet ! , seems there is erosion to my electrodes

why the titanium cathode goes dark like this ?

No participation at all for any chlorate ! it is very weird and I am going crazy !

greenlight - 8-10-2015 at 07:49

That is really weird.
My titanium cathode went dark too but that hasn't affected further runs, I just wash it in dilute HCI before use.

specialactivitieSK - 8-10-2015 at 10:09

It is possible by this process to produce copper perchlorate ?

ecos - 13-10-2015 at 16:17

Finally it works. I got some chlorate and I burned it with some sugar and it glow

The connection from the PC power supply to the electrodes were bad and caused voltage drop on each terminal (around 0.8 v) , I also noticed the resistance of the titanium cathode is so high compared to the MMO anode and this also caused voltage drop which made the voltage in the electrolyte very small (< 3v) I think this was the problem.

I used large steel bolt as cathode and fixed the connections between the power supply and the electrode and I started to notice the KClO3 appearing in the second day.

I found some videos on internet on howto make MnO2 anode for chlorate cells : https://www.youtube.com/watch?v=nvMVlhBmv7M

They use Titanium as substrate , is it possible to use SS as substrate instead of Ti ?

[Edited on 14-10-2015 by ecos]

greenlight - 23-10-2015 at 04:22

Nice to see you got it worked out Ecos...

I finally got everything set up for a perc cell except for the electrodes.
Will one of these platinum coated titanium anodes work or should I wait and fork out the extra money for a lead dioxide one:

http://www.ebay.com/itm/PLATINIZED-TITANIUM-ANODE-PLATING-AN...

Also, for a cathode, can I use straight titanium electrode or do I have to use stainless steel?

hyfalcon - 23-10-2015 at 07:45

That should do fine greenlight. I wouldn't let any of my electrodes sit in electrolyte without power running through them.

Titanium is actually the better the the two.

[Edited on 23-10-2015 by hyfalcon]

ecos - 23-10-2015 at 10:49

Quote: Originally posted by greenlight

Nice to see you got it worked out Ecos...

I finally got everything set up for a perc cell except for the electrodes.
Will one of these platinum coated titanium anodes work or should I wait and fork out the extra money for a lead dioxide one:

http://www.ebay.com/itm/PLATINIZED-TITANIUM-ANODE-PLATING-AN...

Also, for a cathode, can I use straight titanium electrode or do I have to use stainless steel?

As a cathode it is not a problem to use any kind of electrode. SS or Titanium would give almost the same result.
per my experience, SS has better conductivity and this will reduce the voltage loss on it. It also cheap compared to titanium.

after doing the electrolysis you will find a dark layer on the cathode which has high resistance. You would need to remove it with HCl or sandpaper for the next round. This would mean losing of the cathode weight by time.

below is the picture of my cathode (it was pretty shinning before, but looks ugly after electrolysis). I used sandpaper to clean it.

My advice :
1-use TWO SS bolts on each side of the anode. this will generate gasses on each side of the anode rather than one side.
2-save the titanium and plate it with MnO2 or PbO2 (I prepare a thread for this but still needs time). you would be able to use it as anode for another cell.

Try to report the current and results

I am waiting for it

[Edited on 23-10-2015 by ecos]

greenlight - 23-10-2015 at 22:31

Thanks guys, I will run it with that Pt coated anode and a titanium cathode and post results and specs when finished.

greenlight - 28-9-2016 at 09:08

I have some experience with making potassium chlorate via electrolysis now and I am ready to attempt a perchlorate cell.
I have a 5v 20 amp power supply from making chlorate and a 5v 40 amp unused power supply. I think I will use the 20 amp power unit as I am only going to use a 1 litre container for the cell as a test unit.

So just to check before I start the cell up:
1# I charge the cell with saturated sodium chloride solution and begin electrolysis with MMO anode and Ti cathode.
2# After the amount of time running that usually gets me a yield of chlorate for this size cell, I change the anode to the platinized one and begin checking samples of the electrolyte with methylene blue for signs of perchlorate.
3# Try and estimate time to near completion using calculations from the various webpages on chlorate and perc manufacture.
4# Double decomp with potassium chloride solution and then recrystallise and wash product until no sign of chlorate left.

Does this sound right?
All help much appreciated

ecos - 29-9-2016 at 03:09

Hi Greenlight,

I don't think there is a need to use two electrode, the Pt is enough

you can check this video for deep details : https://www.youtube.com/watch?v=O1aWzrRBMjk

why don't u use two cells together, one for chlorate and the other for perchlorate ?

greenlight - 29-9-2016 at 03:44

Hey ecos,
I didnt mean use two electrodes, I mean use the MMO anode and titanium cathode and then when the sodium chlorate levels get high I will swap the MMO for the Pt coated anode...
Then it will just have Pt anode and titanium cathode.

I will check the video out when I get home tonight

ecos - 29-9-2016 at 06:53

I totally understand you.

but why to use MMO then Pt if you can use Pt only by converting from NaCl to NaClO4 directly?

hmm let me guess, is it due to that perchlorate will not form till chlorate reach a certain level which is low enough to destroy your Pt anode?

if yes, you can use Pt to get chlorate with certain level then filter them out and use the chlorate to get perchlorate!

it was hard in my cell to change the anode since I used epoxy to fix it.

you will find some basic things that you didn't mention in your steps : 1) boiling water to get over saturated solution .... blah blah

greenlight - 29-9-2016 at 10:28

I thought the least I could use the platinized anode the better in terms of reducing wear on it.
I have heard high chloride levels are hard on it.
I want to go from NaCl to NaClo3 and finally NaCl04 before double decomposition with KCl.

And yes, I forgot to add some small steps like the boiling to attain a saturated solution but I do do that every time I charge the cell electrolyte for my chlorate cell

yobbo II - 29-9-2016 at 12:07

It's SMALL chloride levels that are hard on the Pt anode.

ecos - 29-9-2016 at 23:59

Ref : http://www.oocities.org/capecanaveral/campus/5361/chlorate/a...

I and yaboo are right , for low levels not high levels !

greenlight - 30-9-2016 at 01:28

Whoops, regardless I still want to start with the MMO and then switch over after near conpletion to chlorate.

I am cleaning my titanium cathode in dilute Hcl today and wirebrushing off any buildup of crap on it. The MMO anode was just washed lightly as I don't want to scrape any of the coating off. I am also looking for a larger container for the cell like 2 to 3 litres.

ecos - 30-9-2016 at 11:34

Good luck and looking forward for your result

greenlight - 28-10-2016 at 08:57

I have finally got the cell finished after a few problems and it has been running for 2.5 hours now.
I am using a 2.25 litre container this time with a 5v 20 amp power supply.
The plan is to run the cell as a sodium chloride cell and convert most of the chloride to chlorate, then recharge the cell solution with sodium chloride and electrolyze again then repeat a couple of times to build up the sodium chlorate concentration. Sodium chloride solubility in water is something like 350g/L @ 25C and sodium chlorate is something around 700g/L @ 25C so once it is converted to chlorate, the cell can hold twice as much dissolved in solution.

Then I will convert to sodium perchlorate with a Pt anode. I can either crystallize the sodium chlorate and start a new cell solution or put the original cell solution straight into the perchlorate cell.

I have calculated the run time at 54% efficiency just to be safe and at my cell size it will take 43.80 hours to convert 86% chloride to chlorate. I will run for 40 hours before recharging with sodium chloride again.

[Edited on 28-10-2016 by greenlight]

ecos - 2-11-2016 at 03:28

It looks so nice.

did you try to measure the current? why don't you use a power meter to monitor Voltage, current and power?

from my experience , the voltage and current on the cell will drop after long running time due to different reasons:
1- the temp on the supply rise; voltage will drop down. you can use a small computer fan to solve this prob
2- conc. salts will decrease in electrolyte ; conductivity decrease; current decrease. you can add more salt

just don't get surprised , this is normal.

greenlight - 2-11-2016 at 05:41

Thankyou.
I am looking into purchasing a voltmeter/ampmeter to measure the current flowing through it.
It has been running for 45 hours now and some of the electrolyte was evaporated today and the crystals mixed with sugar. The mixture smoldered and almost maintained deflagration on its own which indicates the presence of chlorate oxidiser.

[Edited on 2-11-2016 by greenlight]

ecos - 2-11-2016 at 08:39

Good news
It is better to buy something like this :

tmp_8840-$_1.JPG(2)-626343887.jpg - 30kB

Ref : http://m.ebay.com/itm/100A-DC-Digital-Watt-KWH-Current-Power...

[Edited on 2-11-2016 by ecos]

yobbo II - 2-11-2016 at 10:17

The cells looks exquisit. It's like a piece of David Bowie art!

If you could purchase a coulumb meter (amper hour meter) that would be great.

Laboratory of Liptakov - 2-11-2016 at 14:46

I see excellent results and work describe from ecos and greenlight about preparation NaCl =O3=O4. Plastic explosive on NaClO4 base will be early ! Thanks behind your work and invention.
Dr...:-)

greenlight - 2-11-2016 at 21:58

Thanks guys

Yes, I will look for and amphour meter voltmeter to meaure the current so I can get an accurate runtime.

ecos - 3-11-2016 at 16:45

If you want to get a better results with easy steps:
1- use stirrer.
2- get the electrodes closer. this will increase the current. you have a very good power supply (20A) so don't get afraid
3- get a 6v power supply.

I don't know why I like to see high currents in the cells.
it is better to calculate the max current that the electrode can operate on and operate at 80% from it.

[Edited on 4-11-2016 by ecos]

greenlight - 4-11-2016 at 04:46

I have heard of using a stirrer before and will consider it if I end up making a 5 litre potassium chlorate cell.

The electrodes are about 1 inch apart in the current cell. I would put them closer but then I would need a cooling bath probably because the electrolyte would get too hot.

My first preference was a 6 volt power supply but I could not find a unit like the one I purchased in 6 volt with an acceptable amperage.

ecos - 4-11-2016 at 15:07

here we go

: http://www.ebay.de/itm/131486861965

greenlight - 5-11-2016 at 02:01

Nice find, you can customise your power supply.
They didn't come up for me when I was looking as they aren't in english I think.

ecos - 25-11-2016 at 14:39

any updates about perchlorate?

greenlight - 26-11-2016 at 01:51

I am awaiting arrival of an lcd display ammeter before running any further so I can get an idea of finish times.
I have done about 100 hours so far.

greenlight - 18-3-2017 at 23:31

I have been busy with work and have only just got around to installing the digital ammeter.
I decided to use an old wooden pallet and some spare pieces of wood sheeting to form a dodgy table for the whole thing with the cell on one side and the electronics on the other with a dividing wall to mount the meter. The attached picture if of the electronic side

The last of the wiring has to be put in and it will be ready to run

[Edited on 19-3-2017 by greenlight]

anodes

Laboratory of Liptakov - 19-3-2017 at 23:40

OK.....devil's device....I am curious..... :cool:

.....LL
Still short questions:
1) For example on 1 liter solution you recommend kathode (-) can be from stainless steel ? For example stainless cup ?
2) As anode (+) for chlorates (xClO3) is best what ? Titanium reactive surface? PbO2 reactive surface ?
3) How large surface anode for 1 liter? 2x3 inch or 2x4 inch ? (5x7,5cm - 5x 10cm) ---sieve mesh type
Thanks..... :cool:

...LL

[Edited on 20-3-2017 by Laboratory of Liptakov]

[Edited on 20-3-2017 by Laboratory of Liptakov]

markx - 23-3-2017 at 05:55

Quote: Originally posted by Laboratory of Liptakov

OK.....devil's device....I am curious..... :cool:

...LL

[Edited on 20-3-2017 by Laboratory of Liptakov]

[Edited on 20-3-2017 by Laboratory of Liptakov]

Cathode material for ClO3- electrosynthesis can be made from stainless steel, titanium or even regular mild steel. If I remember correctly then mild steel (iron) had the lowest overpotential for hydrogen evolution and hence is the most economical option in terms of energy loss, but for amateur use it makes really no difference. I think stainless is the best option for amateur use....widely available and rather cheap. Current density on cathode is not critical.

As for anode the best option is by far MMO. The next best in terms of availability is graphite, but one has to remember that it erodes and wears away in a chlorate cell and contaminates the cell liqour with carbon particles that have to be filtered out in a separate step. Graphite is especially susceptible to erosion under cell liqour temperatures above 40C and excessive current density, but if used in mild conditions it can serve for quite a period of time.
As for the current density on anode...it is a most critical parameter that influences the longevity of the anode directly. For MMO it should be on the order of 0,25A/cm2, but it also depends on the particular MMO composition and there are many. Lower is better in terms of longevity of the anode. For graphite only about 0,1A/cm2 is suggested.

greenlight - 23-3-2017 at 07:22

@ Laboratory of liptakov
1. The cathode I am using is titanium plate.
2. The anode is MMO layer coated in titanium mesh
3. The anodes are both 2x6 inch in size and are fully submerged when the 2.2 liter cell is full.
The power supply is 5 volt 20 amp and I nearly have it all wired up, just need some heat shrink wrap around the connections to the ammeter and fit the cell leads.

yobbo II - 23-3-2017 at 11:36

If you want your graphite to last you must control pH of cell (add HCl acid).

Laboratory of Liptakov - 23-3-2017 at 11:39

Thanks, boys for your experiences.....and for others, of course it are important values......I will using on NaClO3 Two pure titanium flat plate 2 mm thick grade 1 purity. For better counting of current, thus 0,25 A on cm2. In this set is possible reverse polarity. Even is impossible making error in polarity.../huhaha/.....
On 2,2 liter only 20 Amp ? OK...is not voltage much high 5 V ? I read some here even 3,5 - 4,5 Volts max. But higher current. OK, I Believe in your experiences, thanks............ :cool:

..........LL

greenlight - 23-3-2017 at 18:13

20 amp has been fine in the 100 hours the cell has done to raise the temperature to 70 C which is perfect temp for chlorate production.
Once I can work out when all of the chloride has been turned to chlorate using the ammeter , I will switch out the MMO anode with a platinized one to convert to perchlorate.

Laboratory of Liptakov - 24-3-2017 at 00:33

OK, Green, thanks, Cell running only 4 days ? Very good result. It seems on efficiency almost 100%. Thus according this calculator: http://www.vk2zay.net/calculators/?body=chlorates.php
Estimate your cell has 700g NaCl on start procedure. Be that as it wants, NaClO4 is holy grail of all deminers. For next conversions.... :cool:

...LL

markx - 24-3-2017 at 01:10

Quote: Originally posted by Laboratory of Liptakov

Thanks, boys for your experiences.....and for others, of course it are important values......I will using on NaClO3 Two pure titanium flat plate 2 mm thick grade 1 purity. For better counting of current, thus 0,25 A on cm2. In this set is possible reverse polarity. Even is impossible making error in polarity.../huhaha/.....
On 2,2 liter only 20 Amp ? OK...is not voltage much high 5 V ? I read some here even 3,5 - 4,5 Volts max. But higher current. OK, I Believe in your experiences, thanks............ :cool:

..........LL

I hope you are not trying to use titanium metal as the anode for the chlorate cell....this will not work. Titanium will passivate under anodic potential and become unconductive, not to mention that it is unable to convert Cl- to ClO3-. Ti can only be used as the cathode.
Only MMO coated titanium can be used as the anode....or any of the alternatives suggested above: graphite, platinum, lead dioxide and some other oxide based anodes. The only viable options from practical side are MMO and graphite to be honest.
Cell voltage of 5V is plenty enough for most usual electrosynthesis applications, including chlorate conversion. The voltage applied to the cell will only have to overcome the electrochemical potential of the cathodic and anodic reactions plus their overvoltage (depending mostly on electrode material) and for the chlorate synthesis this summary potential lies at about 3,5V. The rest of voltage applied to the cell will be dropped on the negligible ohmic resistance of the electrolyte (and other circuit components) U=I*R and evolve as excessive heat in the electrolyte. So from this it can be seen that a slight increase in the applied voltage will drastically increase the current running through the cell. To avoid excessive current density at the anode one has to have a means to regulate the applied voltage or the distance between electrodes in the cell. Most efficient way of course is to regulate the voltage....most contemporary switching power supplies have a means to regulate the output voltage.
For 2,2l cell under optimum applied voltage a 20A current is quite ok. I run a 5l cell at about 3,7-4,2V 40-50A and the electrolyte temperature will rise to 70-75C under natural cooling. This is quite optimal for a MMO setup, but go any higher with the current and the cell will reach boiling temperature quickly, electrolyte will evaporate, things overheat and it just becomes a huge mess.

Laboratory of Liptakov - 24-3-2017 at 03:16

Fantastic aparatus. Both cathodes thus are stainless plates, between is one titanium sieve with surface from multi metal oxides - MMO. Respectively Iridium oxid and Rhutenium oxid and maybe Titanium oxid are on surface. OK.
I will making almost same construction. Tube /rod output with electric plastic plug is ingenious for replacement - recovery. Well...size cathodes large - surface is not important. Can be 2x or 4x bigger than anode. Or all container can be from stainless steel as kathode. For better cooling. Container is also possible pose in bucket with water and use two 12V fans whiff on level in bucket. After is possible increase current on maximum permission, not voltage of course. OK. It Seems nice. Now still somewhere find MMO. Thanks for important details.............. :cool:

........LL

[Edited on 24-3-2017 by Laboratory of Liptakov]

ecos - 26-3-2017 at 03:57

you can use SS nails/bolts. they also work fine and very cheap.

don't forget to clean them with sand paper every day because something sticks on it from the cell.
I don't know if it is oxidation or what !

metered perc cell update

greenlight - 31-3-2017 at 22:36

I wired the whole system together and ran it but the amps are reading wrong.
With some help from WSM from the apc forum the cause is found to be that the meter is max 200 amp and the shunt is only 20 amp. I need to match the meter amperage with the shunt amperage for the system to be accurate.

[Edited on 1-4-2017 by greenlight]

ecos - 2-4-2017 at 01:13

are u going to drive more than 20 amp in the shunt ?!if yes, the anode will be destroyed with much current.

I advised you in the beginning to use power meter since you just connect its cables and avoid those mismatches

anyway , good luck

greenlight - 2-4-2017 at 21:00

No the power supply is 5 volt 20 amp.

I did purchase a power meter but it requires a shunt to run and the meter is a 1-200 amp meter so it needs to be paired with a 200 max amp shunt for accurate reading.
A replacement shunt is only $5.00 USD so its not too much of a setback.

markx - 3-4-2017 at 14:01

Quote: Originally posted by greenlight

No the power supply is 5 volt 20 amp.

I did purchase a power meter but it requires a shunt to run and the meter is a 1-200 amp meter so it needs to be paired with a 200 max amp shunt for accurate reading.
A replacement shunt is only $5.00 USD so its not too much of a setback.

It is not the ampere range of the shunt that determines the functionality of the setup, but rather the actual ohmic resistance of the shunt. It is essentially a low ohm resistor and the ampmeter is actually a voltmeter that displays the ohmic voltage drop on the shunt as amperes passing through it according to the equation I=U/R. The R in the equation is the resistance that the ampmeter "expects" the shunt that it measures the voltage drop across to have....if the shunt does not have this particular resistance then the reading of the ampmeter is flawed and it does not matter if the shunt is designed to handle 20A or 500A as a maximum.

yobbo II - 3-4-2017 at 15:05

I would imagine that since the same people are selling the range of meters and the range of shunts then the '200 amp' meter goes with the '200 amp' shunt. ie. the resistance of the 200 amp shunt suits that particular meter.

measurement

Laboratory of Liptakov - 4-4-2017 at 05:29

Laboratory of Liptakov - 6-5-2017 at 06:58

Beware of this seller. Sells very low quality platinum anodes.
http://store.theamateurchemist.com/platinum-titanium-anode-2...
All describe here: https://www.youtube.com/watch?v=xV-SaP2iv7s

ecos - 6-5-2017 at 14:54

i tried their MMO anodes and they do great.
it is bad to know that you wasted your money for this Pt anode.
did you contact them for this problem ?

note: are you sure that you must multiply by 2 for both sides ?!
I think 20 A are too much.
usually I use 5-6 A

[Edited on 6-5-2017 by ecos]

Laboratory of Liptakov - 6-5-2017 at 23:14

Of course, that both sides. I putted everywhere minimal 10 question about it. And everybody says, even 2,2x for mesh type, against planar surface. Of course, that without external cooling is possible use only 6 A. I readed before start almost all textes about recommend of current. Current was in toleration, even in his half. In commerce process are use 2x more currents for platinum on cm 2, thus 500mA /cm2. At my was used was current 260 mA/cm2. And it even on only 3 hours. After partially damage was current established12A, thus 160 mA/cm2.

[Edited on 7-5-2017 by Laboratory of Liptakov]

ecos - 7-5-2017 at 02:12

I am not sure but mesh has low surface area. I think you might need to multiply with scaling factor like 0.2 due to the gaps in the mesh.

I am not sure about that but I am thinking with you.

try to send to the website about this problem and understand what was the root cause.
Maybe they will be kind and send you another anode for free.

Laboratory of Liptakov - 7-5-2017 at 02:46

Here is comunication from this forum: Yobbo II say:

yobbo II
Hazard to Others
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Posts: 172
Registered: 28-3-2016
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posted on 28-4-2017 at 07:37 Reply With Quote Report Post to Administrator

Quote: Originally posted by Laboratory of Liptakov
Thanks. Other words 1 cm2 on mesh = 1 cm solid planar surface, counting on one side. Thus, 1cm2 anode (mesh) = 2 cm2 surface as total large for counting of current. Right ?

It is around two times the length x breath of the piece of mesh.

"A major MMO manufacturer told me that their MMO mesh was 2.2 times the basic dimensions."

This quote from here
http://www.amateurpyro.com/forums/topic/3981-the-bucket-cell...

Yob

current to anode

Laboratory of Liptakov - 7-5-2017 at 03:00

rewritte from amateurpyro.com

Firebreather

Donator - HE
PipPipPipPipPip
1,797 posts
Posted 07 December 2009 - 02:27 PM
Arthur, I agree that in the future, it might be easier to simply manually adjust the timer for acid delivery, but it's fun to contemplate designs that do the job for you. A computer would be ideal... I like the notion of a divided vat as well. The DATAQ software has an SDK, and it would be possible to make a dedicated system (probably using Visual Basic, as I am not up on C+) that would be devoted to this particular process. The DATAQ hardware has a pair of outputs that could easily be used to control any hardware desired. Definitely food for thought.

Here is a post I made at Science Madness today: I'm ready to power up the lead dioxide anode made last January for the first time...

The small test cell is completed. I didn't realize initially how small my LD anode really is. It measures 8.9 X 4.6 cm, with a basic surface area of 0.41 dm^2. Given the convolutions, the surface as viewed under a microscope, and the mesh configuration, I am taking a wild guess and multiplying this by 2.4 to determine the functional surface area. A major MMO manufacturer told me that their MMO mesh was 2.2 times the basic dimensions.

This yields a surface area of 98.4 cm^2 or 0.984 dm^2. I'm going to call it 1.0 dm^2 for purposes of current. Literature yields a range of 15 to 35 amps per dm^2, and my thoughts are 20 amps is a good starting point, which can be altered depending upon temperature, with 60 degrees being an upper limit. The fairly small Ti strap is going to limit the current anyhow - this anode was made when my understanding of the limitations of titanium as a conductor was not as good as it is now, and the strap is too small.

The cathode is titanium, and fairly small, yielding a higher current density at the cathode. For the first run, at least, I am not going to add NaF or any other sort of additive. I want to see what sort of CE I can get in the native state.

The only other change I made was the use of viton gasket rather than skived PTFE gasket, with the hope that it will reduce the inevitable salt creep.

Tomorrow, I will mix up the chlorate and power it up.

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