Sciencemadness Discussion Board

Can a perchlorate cell go wrong?

Chemgineer - 29-6-2024 at 10:13

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?

greenlight - 29-6-2024 at 10:43

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.

Chemgineer - 29-6-2024 at 11:00

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.

Chemgineer - 29-6-2024 at 12:29

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.

greenlight - 29-6-2024 at 19:44

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.