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Simoski
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Cool Pinko, thanks
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Simoski
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Good chlorate anode materials?
Yobbo II or anyone else do you think the following materials will make a good anode ...
lanthinum calcium manganate
or
lanthinum strontium manganate?
( the latter being used as a cathode in solid oxide fuel cells (SOFC) )
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Simoski
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Electrolysing scrap steel to make iron oxide has taught me this about steel anodes, cast iron disk brakes last much longer.
Put another way cast iron is far more inert than mild steel.
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Gearhead_Shem_Tov
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Quote: Originally posted by Simoski  | Electrolysing scrap steel to make iron oxide has taught me this about steel anodes, cast iron disk brakes last much longer.
Put another way cast iron is far more inert than mild steel. |
Would that be because of cast iron's much higher carbon content do you suppose? Cast iron has about ten times the carbon content as mild steel.
-Bobby
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Simoski
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| Quote: Originally posted by Gearhead_Shem_Tov | | Quote: Originally posted by Simoski | Electrolysing scrap steel to make iron oxide has taught me this about steel anodes, cast iron disk brakes last much longer.
Put another way cast iron is far more inert than mild steel. |
Would that be because of cast iron's much higher carbon content do you suppose? Cast iron has about ten times the carbon content as mild steel.
-Bobby |
Bobby I am not sure exactly it just seems to me that it is more dense, more solid.
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Simoski
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There is a channel on YouTube where a guy squashes all sorts of things in his industrial press. This got me thinking... what if we took MnO2 powder
and squashed it under immense pressure ( like 50 tons / square inch ) would it fuse into a solid piece that we could use as an anode? Could we do the
same to PbO2 powder?
[Edited on 27-4-2019 by Simoski]
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Simoski
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What about Zirconium as an inert anode for chlorate / perchlorate production, will it passivate like titanium?
Let me answer my own question:
Zirconium is a member of the family of 'valve metals' (an archaic term), which form a strongly passivating oxide film when exposed to air and/or
water. From here:
Owing to their low electrochemical potential the group IVB and VB valve metals Ti, Zr, Hf, V, Nb and Ta readily react with water or oxygen to form a
dense, protecting passive layer.
[Edited on 3-7-2019 by Simoski]
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Simoski
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| Quote: Originally posted by Simoski |
Zirconium is a member of the family of 'valve metals' (an archaic term), which form a strongly passivating oxide film when exposed to air and/or
water. From here:
Owing to their low electrochemical potential the group IVB and VB valve metals Ti, Zr, Hf, V, Nb and Ta readily react with water or oxygen to form a
dense, protecting passive layer.
[Edited on 3-7-2019 by Simoski] |
I now wonder if Zr, Hf, V, Nb and Ta would make as a good a cathode in a chlorate cell as Ti? I wonder because Ti is an excellent Chorate Cell
cathode.
Ti passivates as an anode but makes a very stable cathode.
[Edited on 29-7-2019 by Simoski]
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Simoski
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Electron Well
Since it seems to me to carry these thoughts forward, let me continue by saying thank you to all those before and after.
BUT HEAR ME NOW:
THE ANODE IS AN ELECTRON WELL... a sink for electrons, down you go electrons, down you go!
One can imagine being miniturised to the point where an electron was the size of your head, then standing on or against an anode immersed in an
electrolytic cell. Looking out through the electrolyte one would see these football sized "electrons" moving through the electrolyte and then sinking
into the anode, gone.... ??? no but the appearance of gone, rather absorbed for further transmission.
The cathode is therefore an electron font or spring or source.
[Edited on 29-7-2019 by Simoski]
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mysteriusbhoice
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conductive epoxy will fail because the epoxy actually degrades in solution as the cell runs so you need to impregnate a plastic that wont degrade one
such would be whatever your cell is made of HDPE so that would be a good choice to mix conductive graphite mud/powder into
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Tamerlane
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Here's an interesting article which uses a particle bed anode of lead dioxide to make perchlorate, with an MMO current feed. An amateur-friendly idea could
be to employ a trough or pan with an MMO mesh placed at the bottom and a PbO2 "sand" pressed in above it.
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mysteriusbhoice
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| Quote: Originally posted by Tamerlane | | Here's an interesting article which uses a particle bed anode of lead dioxide to make perchlorate, with an MMO current feed. An amateur-friendly idea could
be to employ a trough or pan with an MMO mesh placed at the bottom and a PbO2 "sand" pressed in above it. |
the thing with this cell is that you need a good diaphragm pump to actually flow liquid through the cell also even if its just standing you would need
tons of PbO2 powder and at that point its way better to use epoxy,acrylic,PVC and PbO2 composite electrodes since those do work just use recyled Ti as
substrate and not graphite!!
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flaminglasrswrd
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| Quote: Originally posted by mysteriusbhoice | | Quote: Originally posted by Tamerlane | | Here's an interesting article which uses a particle bed anode of lead dioxide to make perchlorate, with an MMO current feed. An amateur-friendly idea could
be to employ a trough or pan with an MMO mesh placed at the bottom and a PbO2 "sand" pressed in above it. |
the thing with this cell is that you need a good diaphragm pump to actually flow liquid through the cell also even if its just standing you would need
tons of PbO2 powder and at that point its way better to use epoxy,acrylic,PVC and PbO2 composite electrodes since those do work just use recyled Ti as
substrate and not graphite!!
|
Some quick calculations:
The original article used 5kg of PbO2 in a 5cm layer in a 20cm ID HDPE pipe and 80 amps. That's a current density of about 250ma/cm^2 with PbO2 packed
at a density of about 3 g/cm^3. They achieved 80-90% CE (20-25% higher than conventional parallel plate systems).
At 1/16th scale: 2" PVC pipe packed to 5cm with about 300g of lead dioxide would operate with about 5A. PVC is resistant to chlorinating liquids.
Standard plumbing fittings make assembly easy. Making PbO2 electrochemically from dirt cheap lead metal is also easy if you are actually trying to get
particles.
Flow rates would need some adjusting because the scaling probably isn't linear, but something around 50 ml/min is reasonable. That's achievable with
air-lift pumps which are completely chemical resistant. For better efficiency, a pneumatic ejector pump can be used.
Honestly, I think this is a great option that I'm going to pursue at some point.
STUDY ON AIRLIFT PUMP AS A PUMPING AND AERATION SYSTEM IN AQUACULTURE
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yobbo II
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The Lead Dioxide bed is somewhat similar an Anode make my G. Pinkston long time ago.
http://www.chlorates.exrockets.com/leaddiox/ldslda.html
Changing the subject slightly to DSA, there is an attached article.
Yob
Attachment: denki_anodes.pdf (811kB)
This file has been downloaded 530 times
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yobbo II
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Some more reading.
Yob
Attachment: denki_anodes.pdf (811kB)
This file has been downloaded 437 times
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mysteriusbhoice
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some stainless steel coated with PbO2-CeO2 nanocomposite layer will soon test if its viable.
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B(a)P
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Looking forward to hearing how it goes. Why did you go with a metal ruler as a substrate?
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mysteriusbhoice
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Because its what I had on hand and overall its a really cheap 10 cent steel stick so why not and tho ive established Ti as a viable substrate I really
wanna move onto other substrates which are more accesible like copper for instance.
The main issue I have with stainless steel is adhesion of the PbO2 coating it just doesnt seem to want to stick to stainless steel maybe because its a
flat plate.
It also has issues sticking to Ti plates and seems to only want to stick to mesh type electrodes maybe due to having more surface area to latch onto.
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mysteriusbhoice
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so then I used cerium tin oxide as a coating on HF etched Ti shown in this video series.
part1: substrate preperation.
https://www.youtube.com/watch?v=HG6ZLxmd4MU
part2: painting DTO and baking using blow torch.
https://www.youtube.com/watch?v=cXH1qT3k-9k
Part3: coating of overcoat of PbO2(optional) increases lifetime and improves conductivity TBA
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mysteriusbhoice
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so then I used cerium tin oxide as a coating on HF etched Ti shown in this video series.
part1: substrate preperation.
https://www.youtube.com/watch?v=HG6ZLxmd4MU
part2: painting DTO and baking using blow torch.
https://www.youtube.com/watch?v=cXH1qT3k-9k
Part3: coating of overcoat of PbO2(optional) increases lifetime and improves conductivity TBA
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Sir_Gawain
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For some reason, Ebay has tons of platinized titanium anodes right now like this. I doubt they are real because of the price. Has anyone tested any like this? They ship from the US and have free returns, so I might buy one
and test it.
“Alchemy is trying to turn things yellow; chemistry is trying to avoid things turning yellow.” -Tom deP.
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mysteriusbhoice
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| Quote: Originally posted by Sir_Gawain | For some reason, Ebay has tons of platinized titanium anodes right now like this. I doubt they are real because of the price. Has anyone tested any like this? They ship from the US and have free returns, so I might buy one
and test it.
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Anyhing that looks shiny like that is likely to be a fake because real baked on or plated on Pt shows a rough surface finish because its plated or
baked onto an etched Ti substrate and will never be shiny and smooth in finish.
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Sir_Gawain
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Are you sure plated platinum isn't shiny? This guy made some and they look pretty shiny;https://www.youtube.com/watch?v=TSzgvP0OW-Q. (I still think the Ebay ones are fake though.)
“Alchemy is trying to turn things yellow; chemistry is trying to avoid things turning yellow.” -Tom deP.
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Rainwater
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4 different sellers, all the same thing.
Steel mesh with nickel plating.
None lasted more than a few seconds in a chlorate cell before discoloring.
All where magnetic
None decomposed h2o2.
Full refunds on all of them
Exact same picture and description.
[Edited on 30-3-2023 by Rainwater]
"You can't do that" - challenge accepted
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mysteriusbhoice
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| Quote: Originally posted by Rainwater | 4 different sellers, all the same thing.
Steel mesh with nickel plating.
None lasted more than a few seconds in a chlorate cell before discoloring.
All where magnetic
None decomposed h2o2.
Full refunds on all of them
Exact same picture and description.
[Edited on 30-3-2023 by Rainwater] |
Honestly I have a full guide on making capable electrodes from scratch using only Ti mesh by first plating DTO using an aqueous prep without the need
for dry Cl2. and then plating PbO2 over tht and doing pH non controlled at 11 and temp below 40C so the hypochlorite stays high so that the electrode
doesnt errode.
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