387 replies to this topic

[sasman]

Alany the temprature of the cell is around 60 centigrade..

Raketpeter.. i have tried to eliminate the wicking problem by screwing in a 4 inch length of 10 mm graphite .. which hopefully make's it harder for the soloution to wick up the graphite?...

Also you are right about Nylon!!!?.. i used plastic nuts and bolts and they are starting to fall apart.. .. i also used several tie wraps which must be nylon because they have also broken ..

I am passing 100 amps through the cell and there is no smell of chlorine.. evaporation losses are very small..

I used a small aquarium pump to agitate the solution but that as also corroded.. it lasted about 4 days..Thje thing is it was not the metal that had corroded it was a tiny plastic propeller? that to must be nylon?...

Lil guppy.. i had 2 Pt /Ti mesh anodes similar to those you mention and in my cell after about 2 weeks the Ti anode connection corroded away from the Pt/Ti mesh?...

Also i hope to get around 75% overall efficiency..from chloride >>>perchlorate.

11kg NaCl in the cell should get out over 20 kg of perc ..

[sasman]

Well i tested my cell this morning and i did the methylene blue test and the purple precipitate confirms my cell is now making perchlorate ..

I am hoping to get chlorate down to 5 to 10 g a litre before i turn off the power..is there any tell tale indication of when all the chlorate as been used up?...I dont want to run my anodes to long with very low ClO3 level as this can corrode them very fast?..or will i have to use the indigo carmine test then from that work backwards to calculate how much ClO3 i have destroyed? via the amount of Bisulphite i have used?

[raketpeter]

Well i tested my cell this morning and i did the methylene blue test and the purple precipitate confirms my cell is now making perchlorate  ..

I am hoping to get chlorate down to 5 to 10 g a litre before i turn off the power..is there any tell tale indication of when all the chlorate as been used up?...I dont want to run my anodes to long with very low ClO3 level as this can corrode them very fast?..or will i have to use the indigo carmine test then from that work backwards to calculate how much ClO3 i have destroyed? via the amount of Bisulphite i have used?

I'm quite interested in this particular question having no hands on experience with GSLD anodes. With Pt anodes I always stop the cell when I can smell the O3. Might seem unpractical (who wants to "smell" their cell all the time ), but actually it's not a problem cause I can calculate when my cell will start smelling to within a cuople of hours out of a batch runtime of eight days.
I seem to remember reading *somewhere* that LD anodes have been used for O3 production in a NaClO4 electrolyte. If this is true you shouldn't have to worry about anode degradation. (Parts of your cell not made of LD, metal or PTFE might die VERY quckly once O3 forms - it's very agressive with many plastics, glues, etc.)
I will be most interested in hearing at what NaClO3 concentration you can start smelling the O3.

Best of luck

[sasman]

Raketpeter you have mentioned that your batch size is 1900ml? ..ifso what concetration do you think you get your ClO3 down to?.. and approx how much chemical do you use to destroy the chlorate?..

I have just tried a test to see how much Sodium bisulphite i needed to destroy all the ClO3.. but obviously there was lots of ClO3 in the test sample..

I added 5 ml of my cell solution to 5 ml Conc HCl + 1 ml of Indigo Carmine solution.. it turned brightyellow and boiled giving of yellowish gas...it left a white Precipitate at the bottom of the test tube..i assume this is NaCl ?

I tried adding a 1g at a time to my cell solution even with 4 g of bisulphite it did'nt destroy all the chlorate?.. so i stopped the experiment ill will leave it until i can smell hopefully ozone.. Then retry the test..

[Arthur Brown]

Two thoughts,
What is the analysis of chlorate weedkiller? If it's chloride/chlorate then you are half way to chlorate already.

Stirrers, in my old lab we had a moulded glass propeller on a glass rod that fitted in a chuck on a motor. Also magnetic stirrers were used a lot. a piece of iron wire sealed into a glass tube and a spinning magnet below the vessel, too fast and the mag stirrer didnt stay spinning for long it was thrown off.

[Lil_Guppy]

I just have a quick question. I have been looking around for some info on treating graphite electrodes with linseed oil. On Wouter's site, he says "They can be treated with linseed oil to reduce corrosion. A practical method for the home experimenter has been devised by Rich Weaver, and is well described on Mike Brown's page. Old battery electrodes do not need to be treated with linseed oil." The links I have managed to find to the said Mike Brown's page seem to be broken. Just wondering if anyone knows the new URL, has mirrored the procedure, or knows of some ways to go about it. Thanks.

Edited by Lil_Guppy, 13 May 2005 - 08:22 AM.

[miniskinny]

I have a question, not quite timed very well, but I'm wondering if any of you yanks found a good place to get nitric acid at a low price? I've been wanting to try some of these chemistry experiments but I sometimes lack nitric acid.

[sasman]

Here is a pic of a Platinum/titanium anode 1 week after it had turned from a chloride>>> to perchlorate..


I had 2 of these Anodes left both of them had totaly corroded this morning

In theory the cell had 1 more day to run (at 80% effieciecy) to turn all the ClO3 into ClO4...At first i thought it may have corroded because at low ClO3 concentrations Pt corrodes more quickly..So basically i had left the cell running to long with all ClO3 converted into ClO4.. so hence the corrosion..

I would not have minded if that was the case at least i would have had 10 kg of Sodium perchlorate.. .
But when i came to destroy the resulting ClO3 instead of small amounts ( i had expected 5 g a litre) there was in excess of 100's of grams per litre?.. ..
This pic is 2.5 ml Conc hydrochloric acid + 2.5 ml of the Cell solution.


Notice the white precipitate at the bottom..this approx 0.5 ml.. Also notice the dark yellow colour.. = lots of ClO3 left ..Also in the other pic notice lots of horrible yellow Chlorine dioxide gas!! ..

Now that white PPTE is a very rough guide to the amount of perc the cell has created..the more white ppte the more perc formed .. at least thats what i think? .. When i first noticed the cell had turned into a ClO4 cell there was no white ppte, the longer the cell runs the more ppte is formed.. does that make sense...

Well i have done the same test on my other 15 litre cell..and got the same results..both cells ran at 25 amps..

Now dont forget 0.5 ml ppte for a cell running for 1 week after perc had first formed..this is with Pt anode.. supposedly the best anode..

Now here is a pic of 2.5 ml hydrochloric acid + 2.5 ml cell solution..same test as above ..but this time cell solution was from the PbO2 cell..



Notice the massive difference there is nearly 2.5 ml of ppte!!! also notice the test sample colour is much lighter yellow which indicates less chlorine dioxide which means less chlorate destroyed..which equals a lower concentration of ClO3..

Now i would love to know why has my PbO2 cell apparently produced 4 times the amount of ppte?.. i assume this ppte is = to the amount of perc produced???. so thats 4 times more perc than the Pt anode cell?.

Anyway i may never know.. but i have been pondering the mystery all day..

Also dont forget !!! people who buy Pt/ti mesh anode beware!!! If you have had as much luck as i have with this project you are wasting your money...Dont forget when you buy these Ti/Pt anodes from these electroplating suppliers they probably dont have a very thick coating of Pt...

I have gone through a total of 4 Pt anodes.. The first 2 pt anodes were used for ClO3 to ClO4 when i first corroded them i did not have any chemicals to test the solutions. so i assumed i had done something wrong...so i wrote that down as experience..But it looks a bit dodgy to me...



I would like to hear from other ClO3/4 producers how low there chlorate concentration is before they chemically destroy it.. and how much sulphite/acids you use to to eliminate all traces of ClO3..

to be continued..

[gilbert pinkston]

from my limited experience i have found it is much easier to run the O4 cell untill the O4 starts crystalizing out in those lovely diamond shaped crystals then when it cools many more crystals of O4 come out.........i did this by continually adding NaClO3 untill the crystals appeared let it run a few days more (actually during those last days i topped it off with liquid from a previous run to make use of it).......if you take those O4 crystals (you will be dazzeled by their appearance) and vacuum filter them they are very pure then you heat them with a minimum amount of water to dissolve them add a few drops of conc HCl slowly to see where things are at then more slowly but it dosen't take much and do the indigo test i use very little HCl since i started doing it this way..........if you keep running the cell to get rid of O3 i think you may waste a lot of time electric and maybe precious life time of the annodes...............now in the case of NaCL to NaClO4 you would have to encourage evaporation to concentrate the solution enough or keep adding NaCl in the early days (but if you add too much NaCl NaClO3 will come out ) then in O3 to O4 encourage evaporation or set some NaClO3 aside to add until crystals appear

Edited by gilbert pinkston, 20 May 2005 - 03:51 AM.

[sasman]

Well today one of my 15 litre Perc cells had started producing an ozone smell...I did a very crude test to find out the chlorate concentration ..and i estimated below 5 g a litre ..

Even though there is nomention on any of the 2 main webpages on Chorate/Perchlorate production..The way i estimate the ClO3 level is simply by adding a few ml of Conc hydrochloric acid to a few ml of cell solution..there was a very very slight yellow tinge to the sample... doing the same test on a 10g per litre ClO3 produces a distinct yellow colour.. I dont know if its accurate way of measuring ClO3 but it works for me...

I added 55 ml of Conc Hydrochloric acid to the cell solution then placed the cell solution into a 19 litre stainless steel stock pot..i used a portable gas ring to boil the solution.. while it was boiling/simmering i started adding 20 g at a time of Sodium metabisulphite...

After each addition i tested a 5 ml sample with the indigo carmine test..after adding a total of 80g there was no discoloration i dont know how far i have over shot with the bisulphite?.. but cant be worse than 19 g..contamination..

i have left it overnight and will test it again tommorrow..all i need do then is add some hydoxide and then some ammonium salt so i can create some Ammonium perchlorate..hopefully the yield should be around 8kg or 9kg after recrystalization

The only problem i ha d to day was the stainless steel stock pot had a small hole develop after about an hour of boiling... .. dead unlucky....again.. then on my Variac transformer the 100+ total amps as taken it's toll and welded the contacts so i cannot vary the current anymore ...On closer examination the 240 v plug socket has totaly disintgrated burnt black burnt both the socket and plug ..

So i had to turn off my big cell ..until i can fix my variac..

Also on close inspection of my 15 liter cell's anode the PbO2 coating has not corroded at all. But were the PbO2 coating ended the graphite had been eaten away even tho i had tried to protect it with silicone sealer..there was no wicking of any kind.. and the electrical connections were as good as new..

There were a few signs of corrosion on the Titanium anode just odd pin pr**ks were the surface had been attacked..

Next time i wil pay more attention to the graphite/PbO2 area with lots more silicon sealer..

too be continued...

[Arthur Brown]

Remember that titanium performs badly in oxidising conditions! Even divers are not recommended to use Ti regulators for high oxygen mixtures.

[Pretty green flames]

Maybe a bit of a noobish question but still.

Recently i found some pool chlorinating tablets on which it says 80% active chlorine.
Is this good to use for small scale production of KClO3

[alany]

Not really, such a high chlorine figure generally means it isn't hypochlorite at all.

I can tell you from personal experence the process with hypochlorite sucks. The yield is pathetic and the process is just a dog. Don't bother, go with electrolysis. Making chlorate is so trivial there's no reason not to give it a go.

[Arthur Brown]

[quote=Pretty green flames,May 30 2005, 11:09 AM]
......Recently i found some pool chlorinating tablets on which it says 80% active chlorine........

That will likely be di-chlor iso cyanuric acid, or a mix of di and tri chlor. Its a heterocyclic six membered ring alternating C and N with a Cl on two or three of the carbons. More likely it would be a chlorine donor, BUT it dissociates so readily that spontaneous reactions could occur

[pyromania]

Where do you get the copper nitrate and lead nitrate required for making the Pbo2 anode from, i have 70% nitric acid in my chem cabinet so i could disolve lead in the nitric and same with the copper but i dont want to do this as nitric acid is expensive. Is there anywhere you can buy it from in powder form. thanks luke. + are there any laws regarding the construction of a kclo4 cell in your garage (sasman i cant view any of your pics about your cell, it comes up with blueyonder have not given you permison to view this file or something like that ) thanks for the help luke