Chemgineer
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Can a perchlorate cell go wrong?
I have used my PbO2 anodes to go from NaCl to NaClO4 in one step, this takes quite a long time at around 60 days but does work with my bench power
supply.
I experimented a while back of using a 5v 10a LED driver instead of the bench supply and at 60 days I had a feeling it wasn't supplying enough power
because I still had a yellow colour on addition of hcl. I think perhaps the current overload was tripping the power constantly.
I swapped this cell to my bench supply and have run it now for a total of 115 days and i'm still getting chlorine yellow on testing.
Either my LED driver was essentially doing very little and I need the full 60 days (120 total) to reach completion or something else has happened.
Is it possible for a perchlorate cell to go wrong?
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greenlight
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Have you done a test for the presence of perchlorate. I believe methylene blue was the one to use and a purple colour when added to a small sample of
electrolyte was a positive if my memory serves me correctly.
I have a cell and fitted it with a digital amp and volt meter which gives you a readout of the current passing through the cell and is quite handy.
Your doing the conversion from cl to clo3 to clo4 all in one. Have you ever considered running the sodium chloride cell to chlorate with MMO and
titanium electrodes and then using this product this to run in a seperate cell with dioxide to the final perchlorate. Less wear on the electrodes
when the Chloride concentration gets low.
There is a large amount of information on chlorate and perchlorate cells on the amateur pyrotechnics forum (APC) by a member who goes by the Username
WSM. He has some very informative tutorials with pictures on his profile page.
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Chemgineer
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I have done the MMO process previously but have repaired my worn MMO anodes by plating them with PbO2 so now i'm trying this process.
My usual test is to take a sample in a test tube and add some hcl. When there is no more chloride there is no change in colour to yellow.
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Chemgineer
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Quote: Originally posted by greenlight  | Have you done a test for the presence of perchlorate. I believe methylene blue was the one to use and a purple colour when added to a small sample of
electrolyte was a positive if my memory serves me correctly.
I have a cell and fitted it with a digital amp and volt meter which gives you a readout of the current passing through the cell and is quite handy.
Your doing the conversion from cl to clo3 to clo4 all in one. Have you ever considered running the sodium chloride cell to chlorate with MMO and
titanium electrodes and then using this product this to run in a seperate cell with dioxide to the final perchlorate. Less wear on the electrodes
when the Chloride concentration gets low.
There is a large amount of information on chlorate and perchlorate cells on the amateur pyrotechnics forum (APC) by a member who goes by the Username
WSM. He has some very informative tutorials with pictures on his profile page. |
Ok so I added a little 1% methylene blue solution to a sample of the cell and it does indeed turn purple. I guess it just needs more time to
complete.
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greenlight
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Great sign, you got perchlorate
It's always difficult with the perc cell because the product doesn't have a visual precipitate as you run it.
there will be a small amount of chlorate remaining at the end and this is only a major problem if you intend to double decomp into ammonium
perchlorate. There are methods to destroy this residual chlorate in the cell electrolyte and obtain pure perchlorate salts though.
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ManyInterests
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OK, so I am bumping this up because I FINALLY (after almost 3 years) am getting around to making perchlorates. I looked through some videos (but not
all of them) and I did see synthesis that start from chlorate or start from chlorides. I decided to go through the sodium chloride route, and am using
sodium persulfate as a pH modifier.
So far my voltage is 5.4 and amperage is 25 on average. I started with around 500g of sodium chloride with 2 liters of distilled water. I am using a
commercially purchased PbO2 anode and 2 titanium mesh cathodes.
So far it is almost 36 hours run time. I had to replenish the liquid with more persulfate solution and the current is very stable.
I've been looking through documentation on sodium perchlorate synthesis and my old videos, but if possible, can I have a more condensed version?
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Chemgineer
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I used 930g sodium chloride, 1.8l saturated solution plus another 1l of saturated NaCl topped up gradually as the cell evaporated. After that I
allowed the cell to run and topped up with distilled water when needed.
After 60 days @ 10 amps using PbO2 anode and titanium cathode I typically did not get a yellow colour on adding hcl to a test tube sample of the cell.
Then after filtering through a funnel with cotton ball squeezed in the neck to remove any lead compounds you have a sodium perchlorate solution.
Now mix 100ml of the NaCLO4 perchlorate solution with 150ml of saturated KCL potassium chloride solution (you will get an immediate crashing out of
potassium perchlorate, but the cyrstals are very fine and may go through a filter so....) immediately raise the volume to around 800ml with boiling
water and stirring until everything dissolves and the solution goes clear. Now allow to cool, you will get the final product crashing out as it
cools, place in a freezer to get the best yield and then filter off the solid.
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ManyInterests
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| Quote: Originally posted by Chemgineer | I used 930g sodium chloride, 1.8l saturated solution plus another 1l of saturated NaCl topped up gradually as the cell evaporated. After that I
allowed the cell to run and topped up with distilled water when needed.
After 60 days @ 10 amps using PbO2 anode and titanium cathode I typically did not get a yellow colour on adding hcl to a test tube sample of the cell.
Then after filtering through a funnel with cotton ball squeezed in the neck to remove any lead compounds you have a sodium perchlorate solution.
Now mix 100ml of the NaCLO4 perchlorate solution with 150ml of saturated KCL potassium chloride solution (you will get an immediate crashing out of
potassium perchlorate, but the cyrstals are very fine and may go through a filter so....) immediately raise the volume to around 800ml with boiling
water and stirring until everything dissolves and the solution goes clear. Now allow to cool, you will get the final product crashing out as it
cools, place in a freezer to get the best yield and then filter off the solid. |
Maybe the reason why I have so much contamination in my stuff is because I didn't let it run longer? At any rate. I am doing a 2nd synth, 2000ml water
with 4g/l sodium persulfate and 600g of sodium chloride.
and I am doing it with a new step up that had the electrodes be much closer. I am running into problems with my wires burning out, but I think I am
mostly over that... amperage is 30 and over when things are fine. which is more than what I can say for the other stuff.
I was planning on letting my synthesis run for a full week, but after seeing your stuff, I think I'll let it run for 2 weeks. I am replenishing not
with NaCl solution, but more persulfate solution. I'm going to keep doing it with that, we'll see what happens.
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