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Author: Subject: Thoughts On Anodes
Simoski
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[*] posted on 2-1-2019 at 08:19


Quote: Originally posted by pinko  
Here is a description of my experience making Pt anodes. It took some time mastering the process but the results are excellent.

http://www.blog.exrockets.com/blog/making-platinum-foil-and-...

Welding Pt-Pt and Ti-Pt for the home scientists is not difficult. Pt-Pt welds are done with graphite and Ti-Pt welds using DIY spot welder.

http://www.blog.exrockets.com/blog/diy-spot-welder/

Hope the information will be helpful.


Cool Pinko, thanks




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Simoski
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[*] posted on 2-1-2019 at 08:30
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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[*] posted on 16-2-2019 at 14:45


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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[*] posted on 16-2-2019 at 16:20


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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[*] posted on 30-3-2019 at 11:14


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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[*] posted on 26-4-2019 at 21:47


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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[*] posted on 2-7-2019 at 22:44


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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[*] posted on 29-7-2019 at 07:39


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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[*] posted on 29-7-2019 at 07:54
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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[*] posted on 26-4-2020 at 01:38


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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[*] posted on 31-7-2020 at 14:09


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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[*] posted on 7-12-2020 at 22:40


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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[*] posted on 7-3-2021 at 20:03


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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[*] posted on 25-3-2021 at 12:12


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 271 times

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yobbo II
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[*] posted on 11-11-2021 at 15:10


Some more reading.

Yob

Attachment: denki_anodes.pdf (811kB)
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mysteriusbhoice
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[*] posted on 23-1-2022 at 23:54


some stainless steel coated with PbO2-CeO2 nanocomposite layer will soon test if its viable.

PbO2 on SS.jpg - 22kB
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B(a)P
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[*] posted on 24-1-2022 at 01:02


Quote: Originally posted by mysteriusbhoice  
some stainless steel coated with PbO2-CeO2 nanocomposite layer will soon test if its viable.



Looking forward to hearing how it goes. Why did you go with a metal ruler as a substrate?
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[*] posted on 24-1-2022 at 08:15


Quote: Originally posted by B(a)P  


Looking forward to hearing how it goes. Why did you go with a metal ruler as a substrate?


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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[*] posted on 6-11-2022 at 06:47


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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[*] posted on 6-11-2022 at 06:47


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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