387 replies to this topic

[Frozentech]

I got my chlorate cell running about 6 hours ago and it is working a lot faster than I expected! After 6 hours I have about a one inch layer of chlorate on the bottom of the container (coolwhip container) I am very excited for when I get my strontium and barium carbonate.

Are you going to be making some Barium Chlorate ? Do be even more cautious than you would with Potassium Chlorate. Barium Chlorate is an actual documented master pyro killer, having done in a PGI Grand Master ( and officer of the Guild ) along with his wife when a batch of Barium Chlorate stars went spontaneously combusted. Oddly I just saw the repost on the history of this accident on rec.pyrotechnics today.

[completebeginner]

No I am far too scared to make barium chlorate I am excited because I will be able to make green and red stars in time for christmas

Edited by completebeginner, 21 November 2005 - 02:07 AM.

[completebeginner]

so iput nacl through the cell for 3 days and tried to get kclo3 from the naclo3 formed and i didnt get anything, nothing at all, i had a graphite anode and a stainless steal cathode, all that i got out of it was a large amount of black carbon water. any ideas on what went wrong

Edited by completebeginner, 29 November 2005 - 06:43 AM.

[alany]

At 54% efficiency it takes over 3 hours to make 1 gram of Chlorate at a 1 Amp cell current. For 3 days you are looking at about 25 grams per Ampere. Your efficiency may have been far worse, especially if the cell was running overheated with carbon electrodes.

[evilgecko]

I was wondering I you could use gasket sealant between the electrodes and container? It is basically dissolved rubber which sets into a harder structure than silicone sealant. Or would chlorine attack it?

[pkhow]

Can anyone help with a link for info on practical PH control of a chlorate cell. Any idea of how much HCL per Litre would be required to get PH down at the end of cell run time? Also what would be the best indicator/method for measuring PH.
PNK

[alany]

I tried liquid gasket once, it didn't last long, especially submerged. Epoxy is the best, some kinds are better than others. Some crappy two-part I got from a discount store seems quite resistant.

No gasket at all, while annoying with creeping crusts (especially with KCl cells), is probably the easiest, just wash down the crust every few days, I use a wash bottle and give it a squirt when it starts getting bad.

I've done a bit of thought about pH control. I suspect a commercial pH electrode would have osmotic problems with continous operation in the strong nasty cell liquor. An syringe infusor pump would be an elegant solution, it may even be possible to run open-loop if your cell is large and the conditions change slowly. A simple gravity feed with a solenoid valve and a PC controller would be ideal, it could monitor other cell parameters too, like current and temperature.

[gilbert pinkston]

last year i converted a 40# bag of NaCl to NaClO3 to NaClO4 in gallon pickel jars
in making the chlorate i used graphite annodes and both annode and cathode were about four inches below the surface of the liquid to which about 2 g/l dichromate was added
when the cell was started the color went from orange to yellow to green
using a funnel and tube that reached the bottom of the jar i added HCl VERY SLOWLY (this can give you a blast of chlorine and worse) until the original yellow or orange started to appear this was my pH indicator but i did this every day not just at the end i used a total of about one gallon HCl
pH control is supposed to help the graphite and efficency i think
the worst thing by far for graphite is to let the cell go into the perchlorate mode

[pkhow]

I am going to try a PH sensor I have and a small peristaltic pump which is used commercially for the delivery of HCL. I don't hold out a lot of hope for the probe! I also get a blast of chlorine when HCL is added and are having a lot of trouble with the indicator I am using. Any idea's on what HCL demand is likely to be as it seems far too high.
PNK

[gilbert pinkston]

i saved a web page on industrial manufacture and it seems a gallon of HCl per 50 pounds of NaCl is about right and thats what i used with the dichromate pH indicator method (if thats what its doing)
it may help to do as i did and get your annodes under the surface of the solution as far as possible if you are not already....chlorine released close to the surface probably has little chance of being absorbed
in my next cell i will use my funnel and tube to the bottom HCl feed method and add a sepratory funnel slowly dripping a solution of NaCl and weak HCl
how much HCl have you been using?

[pkhow]

My electrodes DSA(MMO) type are in a closed horizontal 1.2 ltr chamber plumbed to circulate through another vertical chamber mounted above the electrode cell. My electrolyte of 1kg NaCl in 3Ltr and after 16 days it should now be mostly chlorate. I have been adding 5ml HCL at a time which now it looks like is way too little. The 1Gal to 50lbs (approx 150ml to 1Kg) is this over the complete run time?
PNK

[gilbert pinkston]

wow DSA well i know nothing about that i used graphite because it was cheap off e-bay and if your good to it it preforms well and lasts a long time
i used almost a gallon of HCl for the 40 pounds that was adding a little each day i had four to six gallon jars going at a time and it took six to eight weeks to convert it all.....i lost very little graphite and did no filtering just boiled and let the graphite settle out
graphite shouldnt go over fourty degrees C because of erosion they say....when i ran it hotter i dont know about erosion but because of evaporation concentrating the electrolyte i could keep adding brine and remove crystalized NaClO3 directly from the cell
if DSA is like platinum and can be run hotter chlorate may be dropped out the same way that would be nice but like i say i have no experience
and very important does chloride concentration effect DSA?
does HCL help preserve the DSA or do you want to add it to increase the efficiency?

[pkhow]

My cell runs at 60~70 degC and in 2 weeks I have had very little loss from evaporation. I will have to give some thought to passing air over the top as evaporation like you are having sounds a lot simpler than having to boil it down. I don't know what the max temp is but I have had it running close to 90deg but I think it should be kept under 80deg if I want a long life. I want to get the PH correct before crystalizing out the chlorate as this is what I have read you should do.
Are you adjusting the PH before you take out any chlorate?
I am trying to get active PH working just to see if I can and from what I have read it should increase the efficiency up from just over 50% closer to 80%.

[gilbert pinkston]

i added HCl every morning and evening because of effiency and its supposed to preserve graphite
at higher temps my NaClO3 crystalized out in the bottom of the jars and on the annode and cathode
i don't think it was much trouble to remove but you may want to be carefull and not scratch or even touch your annodes with the graphite i didnt care
if you could get some evaporation but keep that nasty mist down, and keep the temperature up and possibly top off with saturated brine you might be able to empty the cell place the electrolyte in the freezer and get enough NaClO3 out then heat it back up with more NaCl and start the cycle over again. you could be running two batches continuosly
you would have to work out the details if you wanted to fool with it
NaClO4 is so much better because you can keep adding dissolved NaClO3 and after a while the perchlorate drops out in big diamond shaped crystals
if you can please tell me about those annodes i may want to try them

[pkhow]

ou can scrape MMO material with plastic or wood as long as it is not a metal scraper. I believe that commercially most chlorate cells now are this type of anode but not for perchlorate as they do not like it when the chloride reaches low levels. This newer material is supposes to be able to with stand chloride below 0.3% so may survive the change into a perchlorate cell. I must try and get the evaporation up because a continuos crop of chlorate is what I am trying to get but the run time is complete with only a very small amount of extra chloride having been added. The only way to get any out is by evaporation so if this was happening during running it is a definite advantage.