Mild Carbon Steel Sulphuric Cell

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Ok Phil

I already said your cell was very cool --- but it just keeps getting better every time I look at the new pics you post 8) :mrgreen: :lol:

Kurt
 
jason_recliner said:
I just found a couple of microwave turntable motors. Just in case you ever feel like automating, these things run at 5 rpm.
Wondering if the speed could be made variable, say 3-10 rpm range, and how. They have a good torque..

Marco

Edit: clarity
 
Most gold plating strips pretty fast in sulfuric and the tumbler doesn't necessarily need to be motorized. Hand cranking every 15-30 sec, or so, just to change the positions of the parts, would probably work OK.
 
goldsilverpro said:
Most gold plating strips pretty fast in sulfuric and the tumbler doesn't necessarily need to be motorized. Hand cranking every 15-30 sec, or so, just to change the positions of the parts, would probably work OK.
I thought that too. I was just putting it out there since I read the rpm and made a mental connection with something I had read.

Marco, mine are Australian models and therefore built for 240Vac/50Hz. I suppose you could double it to 10rpm just by doubling the input power frequency. That's if you wanted to build a 100Hz 240Vac power supply which, unless you're a power electronics wizard, is probably more trouble than running it through a gearbox. And to slow it you would need a gear reduction. Because if you gave it 240Vac at 30Hz you would get 3/5 the original rpm but would saturate the magnetic core. I would give it 5 minutes before it burns out.

[Edit for spelling.]
 
Most gold plating strips pretty fast in sulfuric and the tumbler doesn't necessarily need to be motorized. Hand cranking every 15-30 sec, or so, just to change the positions of the parts, would probably work OK.

Excellent point, these tumblers are copied from units designed to put plating on the parts, so a nice slow tumbling action assures a good uniform plating job that looks good too. Since your unit is for stripping only, you want the plating off and don't care much if the stripped down parts look pretty or not, so Chris is right (no surprise there!) an occasional hand crank should do the trick.

As far as modifying a tumbler motor for adjustable RPM, I would pass on that. In refining, where you are talking about exposure to corrosive chemicals and corrosive atmosphere, KISS technology wins out every time.
 
Phil,

I think life would be easier if the basket could easily detach from the shaft so you don't need to remove the entire frame to empty and reload. I see the solution sitting on the side of the tank from that process and it's messy. If you were to cut the main shaft leading to the basket just under the tee the shaft spins in and glue on a coupling to one piece of the shaft and slide in the other end and pin it with a small nut and bolt, it should be easier to just remove the basket. You may have to sand the pipe a bit for the slip connection so it comes out easy.

You may have to reconfigure the dangler a bit so it isn't in the way but freeing up just the basket with a short length of shaft will make rinsing and reloading easier, you could even make extra baskets so they can dry out between rinsing and not dilute your acid too much.

Just a thought.

All in all you did a very nice job, thanks for sharing it with us.
 
Another improvement would be to use a wider stand for the tumbler so you don't need to have it in the acid. If it was sitting outside of the tank you don't need to wash of the acid from the stand, only from the basket.

Göran
 
g_axelsson said:
Another improvement would be to use a wider stand for the tumbler so you don't need to have it in the acid. If it was sitting outside of the tank you don't need to wash of the acid from the stand, only from the basket.

Göran


From what I can see, the back end/bottom of the basket is supported by the frame, so that can't be outside the tank.
 
scrapman1077 said:
g_axelsson said:
Another improvement would be to use a wider stand for the tumbler so you don't need to have it in the acid. If it was sitting outside of the tank you don't need to wash of the acid from the stand, only from the basket.

Göran


From what I can see, the back end/bottom of the basket is supported by the frame, so that can't be outside the tank.
You are correct, it's built like that and I didn't see it at first. I was one step ahead and thinking on how to easily load and unload the basket.

Then I suggest welding a steel ring at an angle near the bottom at the short side where the basket can rest, then there is no more reason to put the tubes inside the acid.

Göran
 
This is an oblique plating barrel made by Sterling, the basket and shaft just slip on and off. At $1500 it is pricey but surely seeing this design some of the more mechanical members can figure out a way to do this inexpensively.

oblique plating barrel.jpg
 
does the metal ever contaminate your precipitate? Or is it not a problem? I always thought a glass container would be best for a stripping cell. Also I noticed some plastic dissolves in Sulfuric acid. Obviously not all does since it is sold in plastic bottles. Perhaps pvc is immune? Knowing what kinds won't disintegrate is very useful no doubt.

I wonder if one could coat the interior with some kind of ceramic porceline type paint? Or maybe polyurethane or epoxy? Perhaps that garage floor coating would work. Just a thought. I'd love to know what plastics are most impervious to sulfuric acid. :idea:
 
Howdy! It's been 3 years... :shock: how time flies!
I'm sorry it's taken so long, but lots of issues kept me from updating the cell.

I decided to try putting together a tumbler, made out of 1/2 inch expanded mild steel; the openings are 5/16th of an inch x 7/8th of an inch... so I lined the inside with 1/8 inch copper mesh.


Today I plan to set up the tank / cooling system and hopefully run some pounds of pins and connectors this coming week while we have dry weather!
I'll be posting pic's as I set up...

Thanks!
Phil
 

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nickton wrote:
does the metal ever contaminate your precipitate? Or is it not a problem? I always thought a glass container would be best for a stripping cell. Also I noticed some plastic dissolves in Sulfuric acid. Obviously not all does since it is sold in plastic bottles. Perhaps pvc is immune? Knowing what kinds won't disintegrate is very useful no doubt.
No. Concentrated sulphuric doesn't attack mild steel. It's not a problem. Well, glass can break... that would be a problem. With a steel tank you do NEED to make sure you DON"T arc!!! Yes, some plastics do, but PVC is not affected. I'm re-using the PVC fittings I used 3 years ago!

I wonder if one could coat the interior with some kind of ceramic porceline type paint? Or maybe polyurethane or epoxy? Perhaps that garage floor coating would work. Just a thought. I'd love to know what plastics are most impervious to sulfuric acid.
If you coat a mild steel tank, you defeat the purpose... it works as your cathode, so you don't need to place a lead cathode.

Phil
 
The dimensions of the tumbler are 5in.W x 5in.H x 12in.L.
IMG_2862.JPG

I'm using some PVC fittings to insulate the tumbler so it doesn't arc while in use.
IMG_2861.JPG
I'll be using a couple of bent rods for moving the tumbler from the bottom of the tank, to the top, in order to drain excess acid, before re-loading tumbler.
IMG_2857.JPG
(For now, I plan to use a small basket, while re-loading the tumbler!)

Thanks!

Phil
 
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