# Mild Carbon Steel Sulphuric Cell



## philddreamer

I started working on a mild carbon steel tank for the sulphuric cell this morning. 
I have a 12" x 7" glass "bowl", but I'll be de-plating dozens of pounds of material, I don't want to take any chances. I hope to start de-plating in the next day or two.

Phil


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## 4metals

Nice tank, it has the ability to run parts in the copper mesh and use the tumbler to hold the parts for stripping as described in this thread. http://goldrefiningforum.com/phpBB3/viewtopic.php?f=85&t=22554

Have you considered brazing on some copper tubing to the exterior of the tank? It isn't too hard to do if you are at all handy and if you put a garden hose adapter on the feed side and a flow control valve on the discharge, you can adjust the flow to keep the sulfuric from getting too hot. The EPA calls this type of cooling non-contact cooling water and it can go right down the drain because it hasn't contacted any chemistry. Then you can crank up the power and not worry about overheating.


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## Barren Realms 007

Very nice looking system.


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## Smack

Phil, if you welded that up, those are some nice beads brother.


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## philddreamer

> Nice tank, it has the ability to run parts in the copper mesh and use the tumbler to hold the parts for stripping as described in this thread. viewtopic.php?f=85&t=22554


Thank you, 4metals! I knew about the post since a read it some time ago, but I wasn't planning on the tumbler since the tank is only 9"W x 18"L x 7"D... I like the idea, though, and will research! 8)



> Have you considered brazing on some copper tubing to the exterior of the tank? It isn't too hard to do if you are at all handy and if you put a garden hose adapter on the feed side and a flow control valve on the discharge, you can adjust the flow to keep the sulfuric from getting too hot. The EPA calls this type of cooling non-contact cooling water and it can go right down the drain because it hasn't contacted any chemistry. Then you can crank up the power and not worry about overheating.


Hummm... you mean, like a radiator? 
I was going to fab and weld onto 3 sides, a "bladder" made of 16ga. ] and run a bilge pump... but it will take me some time, plus I'd have to coat the inside so it won't rust... I'll look into your idea, too! Thanks!



> Very nice looking system.


Thank you, Frank!



> Phil, if you welded that up, those are some nice beads brother.


Thank you Smack! Yes, those are my welds... I've been "practicing" for over 40 years! :lol: 

Phil

edit: correction: the tank is 18" long.


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## philddreamer

Some pic's of the cooling "bladder", (19.5"L x 5"H x 1.5"), added to the steel tank. I need to apply a coat of some type of primer, (inside the bladder), so to keep it from rusting; and then finish with the plumbing. 

Phil


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## FrugalRefiner

Very nice build Phil!

Dave


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## philddreamer

Thank you, Dave!

I'm heading out to buy the hardware... I hope I can have it all hooked up in the next day or two! 8) 

Phil


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## Palladium

I love building things out of steel! That is one fine looking build and i can see the workmanship in it. Very nice!


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## philddreamer

Thank you, Ralph!

Phil


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## Barren Realms 007

Man I don't know Phil. I don't think the thing is going to work to well. I think you need to just pack it up and send it to me. :mrgreen:


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## 4metals

Great job, lots of surface area to keep that sulfuric cool. It will be interesting to see how much power you can apply and maintain an operating temperature under 100 F. You should be able to put a lot of plated pins into 4.9 gallons of sulfuric.


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## philddreamer

> Man I don't know Phil. I don't think the thing is going to work to well. I think you need to just pack it up and send it to me.


NOT!!! :lol: 




> Great job, lots of surface area to keep that sulfuric cool. It will be interesting to see how much power you can apply and maintain an operating temperature under 100 F. You should be able to put a lot of plated pins into 4.9 gallons of sulfuric.


Thank you, 4metals! I can't wait to get going! I added some RUST-OLEUM red oxide primer. After it dries, I'll be adding the protective enamel paint. It should hold the rusting so I can complete the batch. I will check HomeDepot for the proper rubberized rust inhibitor...

Phil


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## philddreamer

Had some free time this afternoon and installed the plumbing. Tried it... and no leaks! :mrgreen: 

I was getting ready to fill the tank with acid and start de-plating, when I realized, that I forgot to install the small valve, so I can drain the acid when I'm done. shazzbat!!!
So I took off to Lowe's, in rush hour traffic; and half way there my wife calls: "I think you forgot something... like your wallet"! :shock: shazzbat! :roll: 
O well, I'lI pick one up tomorrow...

Phil


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## solar_plasma

Very cool :!:


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## philddreamer

Thank you, Solar!
I had to take plumbing off. I need to install a drain valve for when the time comes to drain the 4+ galons of acid.
I've been also researching the tumbler, and I'm putting one together; I happen to have most of the material in my shed. It will speed up the processing of many pounds of the plated material per day...

Phil


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## philddreamer

Drain valve is on and the cell is back together. The buckets will be filled with ice so I'll be running chilled water thru the radiator. I'll be checking both, the acid's and the water's temp...
I plan to test run it tomorrow! 8) 

Phil


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## FrugalRefiner

If you are going to dream... DREAM BIG!!! 8) 

Dave


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## philddreamer

> If you are going to dream... DREAM BIG!!! Dave


INDEED!!! 8) 
Thank you, Dave; I needed to be reminded!

I ran the cell yesterday for 2.75 hours, and de-plated 4.25 pounds of material. I'm happy with the results of the test! I only had 3.5 galons of acid, so I feel it didn't operate to its full capacity. The acid only covered 1/4 inch above the basket. 

The cooler worked!!! I added ice into the buckets and the temp stayed at 70 degrees (+/- 2degrees) in the tank. I had to stir, though, otherwise the temp around the basket would shoot up. 
The current, it would start a 2.7V, then it would run at 5.5V until the de-plating started to end; at this time the volts started to increase. When the voltage reached 9.4V, the deplating was done. The amps 8.8 all the time.

I'll try another run after I get home from work later today.

Thanks!

Phil


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## 4metals

Very nice setup. Looking at the parts you are stripping (or the parts I assume you are stripping because they are on the bench) you can kill 2 birds with one stone by stripping in a tumbler. Agitation comes along for the ride in the tumbler. 

Like all reactions in refining, a constant resupply of fresh solution speeds things up considerably. Probably the most inefficient way of stripping is in that copper basket, sometimes there are no options but by racking parts or tumbling parts you will see an increase in efficiency. 

When you get the entire setup and tumbler running I would appreciate an update with pictures and I will put this in the library so the sulfuric cell threads will have an example of a complete setup when a plan comes together.


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## philddreamer

Thank you, 4metals!
I started the tumbler a couple of days ago, but wanted to work out any bugs on the cooling system before working on the tumbler.
I still need to add some holes in the bowl, glue the pipe in place, set up the anode...

So, the agitation is what speeds things up? When I rotate the tumbler, the items tend to "ride" the bottom... do I need to add a fin? I didn't notice any on the videos of the tumbler. (My PC freezes everytime after a few minutes of trying to look at them).

Indeed! I will share pic's and details of the cell after I finish setting it up.

Thanks to all!

Phil


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## 4metals

Plating barrels of this type are called oblique barrels and the parts stay on the bottom half of the basket as it turns. (gravity has a funny way of being consistent) The dangler which makes electrical contact with the loose parts tends to break them up as they tumble around and make and break contact with the dangler.


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## philddreamer

AHAAAAAA!!! :idea: :mrgreen: 

Thanks!


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## kurtak

Very Cool Phil 8) 8) 8) 

Kurt


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## goldsilverpro

Nice setup, Phil.

In many areas of Washington state, it's quite humid. Strong sulfuric, especially, absorbs moisture from the air. In a non-moving stagnant solution, the lighter water absorbed tends to float, thus diluting the sulfuric, considerably, at the solution level. This diluted sulfuric can attack the steel slowly, creating an etched indentation in the steel at the solution level. Stirring often and covering the tank when not in use can help alleviate this problem. A tumbler would provide constant agitation. Also, keeping the temperature at a low level will reduce the attack. You could also vary the solution level, periodically. Some sort of masking might work, but there are not many things that will stand up to the strong sulfuric - maybe some sort of wax designed for masking in a plating situation. Lead tape would would stand up but the adhesive probably wouldn't. Both lead tape and masking wax are sold by plating suppliers.

You may or may not have etching problems. It's something you should definitely keep your eye on, though. 

When I used a 50 gallon mild steel tank for this purpose, it was in L.A., where the humidity was quite low. After at least 2 years of daily use, there was no visible etching at the surface level.

A few links of a fairly heavy chain might serve well as a dangler contact.


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## Anonymous

Smack said:


> Phil, if you welded that up, those are some nice beads brother.




Smack I am totally with you on this. I'm jealous- my welding looks like ratsh*t.....


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## goldsilverpro

Concerning the possible etching discussed in my previous post, I just thought of something else. You could reinforce the steel at the solution level by welding strips of steel sheet all around the inside of the tank. I'm thinking strips about 1/8" thick X 1" wide, centered at the solution level.


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## geedigity

Good idea! That way it would take a long time to dissolve the "sacrificial" plate, and not the tank itself.


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## Anonymous

goldsilverpro said:


> Concerning the possible etching discussed in my previous post, I just thought of something else. You could reinforce the steel at the solution level by welding strips of steel sheet all around the inside of the tank. I'm thinking strips about 1/8" thick X 1" wide, centered at the solution level.



The same theory as sacrificial anodes on the hull of a warship Chris right?


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## g_axelsson

spaceships said:


> goldsilverpro said:
> 
> 
> 
> Concerning the possible etching discussed in my previous post, I just thought of something else. You could reinforce the steel at the solution level by welding strips of steel sheet all around the inside of the tank. I'm thinking strips about 1/8" thick X 1" wide, centered at the solution level.
> 
> 
> 
> 
> The same theory as sacrificial anodes on the hull of a warship Chris right?
Click to expand...

No, no electrochemical potential here, just making the metal thicker so it would last longer.

Göran


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## philddreamer

> Very Cool Phil . Kurt


Thank you, Kurt!

GSP wrote:


> Nice setup, Phil.


Thank you, Chris!
I did covered the tank with a plastic bag and tied a strap to seal it from the air. It's hot and dry, so a feel moisture shouldn't affect much... I hope!
Thanks for the etching details!!! I'll keep a close eye on the matter.
I'm working on a tumbler, and hope to have it up and running soon. What is the recommended R.P.M's. for the tumbler!?
During the 2.75 hr. test run, the temp stayed below 75 degrees.
I'll be looking into the masking wax.
I'm already looking for some chain!!! :mrgreen: 


> Concerning the possible etching discussed in my previous post, I just thought of something else. You could reinforce the steel at the solution level by welding strips of steel sheet all around the inside of the tank. I'm thinking strips about 1/8" thick X 1" wide, centered at the solution level.


I'm already planning building another tank in the near future, and that will be considered. When I clean this one, I'll add some strips.
Thanks againg, Chris!

spaceships wrote:


> Smack I am totally with you on this. I'm jealous- my welding looks like ratsh*t.....


Practice, practice, practice!!! 8)

I thank you all for your interest and expert advice!!! 8) 

Phil


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## goldsilverpro

You don't want the tumbler turning too fast. Maybe about 5 RPM.


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## philddreamer

Thank you, Chris!

What would be the recommended length of the chain?


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## Anonymous

g_axelsson said:


> spaceships said:
> 
> 
> 
> 
> 
> goldsilverpro said:
> 
> 
> 
> Concerning the possible etching discussed in my previous post, I just thought of something else. You could reinforce the steel at the solution level by welding strips of steel sheet all around the inside of the tank. I'm thinking strips about 1/8" thick X 1" wide, centered at the solution level.
> 
> 
> 
> 
> The same theory as sacrificial anodes on the hull of a warship Chris right?
> 
> Click to expand...
> 
> No, no electrochemical potential here, just making the metal thicker so it would last longer.
> 
> Göran
Click to expand...


You're right Goran clumsy wording on my part. But think around it, what if you could put something on there that effectively took the erosion preferentially over the chassis itself?


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## g_axelsson

I don't think sacrificial anodes inside the sulfuric acid would work. To be working it would have to be active and not passivated by the acid and anything that could be dissolved would go quickly in the acid.

Göran


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## philddreamer

Some pic's showing the progress on the tumbler!

Phil


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## jason_recliner

Looks great. Just an idea for your upcoming patent:
Assuming the lower lip of the colander is below acid level, consider the design idea for some very small angled plastic blades - an impeller of sorts - to help ensure acid in the bowl is continuously replaced. By gently pulling fresh acid in the top, dissolved/powdered gold would flow out the holes more readily.


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## philddreamer

Thanks for the tip, Jason!
There's always fresh acid, as I turn the tumbler...

I also need to tack weld most of the links in the chain, except the bottom one, so it can make better contact.


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## Smack

That stainless chain Phil? Or is it zinc plated? Or maybe just plain, can't tell in the pictures.


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## philddreamer

The chain is just of plain steel...


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## kurtak

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


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## philddreamer

:lol: :lol: :lol: 
Thank you, Kurt!

Mind you... this is the prototype!!! :mrgreen: 

Phil


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## jason_recliner

goldsilverpro said:


> You don't want the tumbler turning too fast. Maybe about 5 RPM.


I just found a couple of microwave turntable motors. Just in case you ever feel like automating, these things run at 5 rpm.


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## MarcoP

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


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## goldsilverpro

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.


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## jason_recliner

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.]


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## 4metals

> 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.


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## 4metals

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.


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## g_axelsson

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


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## 4metals

When Phil gets all of the kinks out he can quit his day job and start selling his units.


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## scrapman1077

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.


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## g_axelsson

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.
Click to expand...

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


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## 4metals

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.


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## philddreamer

Sorry, I'm out of town. Will be back home by the end of the month.

Thanks!
Phil


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## maynman1751

Any updates on your de-plating cell Phil????? Or did I miss them? Great work, sweet cell!!!! 8)


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## beav3r316

maynman1751 said:


> Any updates on your de-plating cell Phil????? Or did I miss them? Great work, sweet cell!!!! 8)



Bump!


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## nickton

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:


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## philddreamer

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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## philddreamer

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


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## philddreamer

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



I'm using some PVC fittings to insulate the tumbler so it doesn't arc while in use.


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.


(For now, I plan to use a small basket, while re-loading the tumbler!)

Thanks!

Phil


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## rickzeien

Have you tried the tumbler yet? It looks like it might make a Faraday's cage.

Sent from my LG-H872 using Tapatalk


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## nickvc

Looking good Phil keep us updated and with your excellent photos 8)


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## philddreamer

Thank you all!
I had a chance today to set up the tank, 


and, started running some batches of TeleCom pins...



First 6 pound batch took 2 hours... I had trouble with my power source; it finally gave up..., so I went to the old battery charger. It took 1 hour to de-plate the second 6 pound batch. Another 34 pounds to go! :mrgreen: 
So far, so good! 8) 

Thanks!

Phil


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## philddreamer

Some pic's of the before and after...


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## philddreamer

I'm de-plating my 4th, 6 pound batch of telecom pins, and my power source keeps shutting off more often... :? 
so it just dawn on me that... my acid might be saturated! :shock: 

What is the maximum grams of gold per gallon in the acid before the process starts to foul!? 
If the expected yield is 1gm /pound x 24# that = 24gm; if 2gm per pound then 48gm... 
would that foul 4 gallons of acid?

Thank you! 
Phil


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## goldsilverpro

Hey, Phil,

I always harvested when the amperage would not fall close to zero, as it should, after all the parts are stripped. When a lot of gold particles float around, the amps will stay pretty high. In the 50 gallon tank I had, stripping 8 hours a day, I harvested about every 3 weeks. I used plating racks that held about 300 all-gold IC packages and I was stripping the very thick Au/Sn and Au.Si brazes plus the 50 microinch gold plating. It took about 20 minutes until the amps were nearly down to zero and everything was stripped.


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## philddreamer

Hi, Chris!
My 3010D DC Power Supply when kaput... so I started using my 12V battery charger @ 2amps, but it gets hot and turns off after constantly running for 5 min. or so. (It doesn't have a fan.) I then ran it for 2 min. at a time, and tumbling the pins in between charges. I was able to do 6 pounds in about 35 minutes.
I've been debating on getting another 3010D or a 6V charger, 2 - 10 amp... but with your comments, I think I'll buy another 3010D. I like the idea of keeping track of the actual amps. 

On another note, I didn't have any issues with the acid overheating... the temp was around 85F. As long as I add ice to the buckets, all is good!
I plan to filter the acid tomorrow...

Thank you!
Phil


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## nickvc

Phil in a sulphuric cell you really don’t want to be adding water, ice, the sulphuric needs to be concentrated for it to work well, this may be causing some of your problems.


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## Yggdrasil

Nick. 
If I'm not fully mistaken, the ice is used in the cooling loop, which is a separate circuit.
See the white PVC tubes in the pic.

Correct me if I'm wrong, Phil.


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## philddreamer

Yggdrasil, you are correct!
Nick, the ice goes into the buckets to keep the water, that goes thru the sealed water jacket around the tank, chilled...


Thank you, gentlemen!
Phil


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## philddreamer

After de-plating 24 pounds of pins, the time came to decant the acid. I had to "brake down" the cooling system in order to tilt the tank and be able to completely drain the acid; so, I added a drain valve at the bottom of the tank, (as previously suggested by a fellow member), for ease draining, without having to disconnect anything...


I also connected a line for vacuum filtering. 
Another 40.5 pounds were de-plated this last week... I tried to vacuum filter, but only 12 hours of settling time is not enough; too much very fine silt clogs the filter in no time!!!

Phil


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## FrugalRefiner

That's a lot of pins! :shock: Looking forward to the melt.

Dave


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## philddreamer

4metals wrote:


> Great job, lots of surface area to keep that sulfuric cool. It will be interesting to see how much power you can apply and maintain an operating temperature under 100 F. You should be able to put a lot of plated pins into 4.9 gallons of sulfuric.]


I checked the temp too early on the first run 2 weeks ago, 85F... last week I checked the temp after an hour of running the cell, and temp was 70F!!!! The trick is the iced water and agitation! 
My power source was my car battery charger... I was running 12v and 10+ amps, lots of "fizzing"! 
I received my 3010D DC POWER SOURCE last Friday... the fizzing wasn't so vigorous, but I could keep better track of the volts and amps.

GSP wrote:


> I always harvested when the amperage would not fall close to zero, as it should, after all the parts are stripped. When a lot of gold particles float around, the amps will stay pretty high. In the 50 gallon tank I had, stripping 8 hours a day, I harvested about every 3 weeks. I used plating racks that held about 300 all-gold IC packages and I was stripping the very thick Au/Sn and Au.Si brazes plus the 50 microinch gold plating. It took about 20 minutes until the amps were nearly down to zero and everything was stripped.


I'm only using 3 gallons of acid... so, after running 40.5# of pins, I started to have a bit of "trouble"; then I remembered that when the amps go to 0, the deplating is done... but while reviewing the previous posts, I understood what happened yesterday, no fizzing and the amps going up and down 1.5 to 2.75 or so...
hummmm… I'll remember next time! 

Thank you gentlemen!
Phil

P.S. 4metals also wrote:


> When Phil gets all of the kinks out he can quit his day job and start selling his units.


Hummmm... I like that idea!!! :mrgreen:


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## archeonist

Is there already a button?


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## philddreamer

The yield from several types of pins that I ran thru the cell was around 10g plus maybe another gram in the filters... those 10g are in one of these buttons. The rest of the buttons are from high yield pins a ran thru PMAR.

Phil


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## bigpagoda

Looks Great Phil! Been waiting to see the results from this project- Really nice.


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## philddreamer

Thank you, Paul!

Phil


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## Bertho

I am looking at building a small version of the cell and was hoping to use PVC and I see some PVC parts in the acid. I looked up a very comprehensive PVC compatibility chart and sulfuric acid was listed as a bad combination. What is your experience with PVC and what alternatives do you suggest? I like the idea of solvent welding PVC.
Bertho


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## philddreamer

Most of the PVC components are used on the water cooling system... but, yes, I've used some PVC on the acid draining spouts. No problems... the acid hasn't affected the PVC at all.

Take care!
Phil


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## rickzeien

How does the solvent welding hold up to the acid?

Sent from my SM-G950U using Tapatalk


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## philddreamer

> How does the solvent welding hold up to the acid?



I haven't used any... for the water lines, I've used threaded couplings; the elbows are just fitted tight. They don't leak. 
For the drain valves, I use threaded valves and Teflon tape, so no "glue" either.

Phil


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## Bertho

Thanks Phil,
Here is the link to the compatibility listing:
https://www.calpaclab.com/pvc-polyvinyl-chloride-chemical-compatibility-chart/

Basically it says it OK as long as not too concentrated (less than 75%) and at low temperature (less than 22C).
Phil's system got good cooling so that is important. How about concentration?
The very old US patent 2,185,858 listed a minimum of 73%


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## FrugalRefiner

You need your sulfuric acid at around 95% give or take a few percent. At 75%, the acid will attack base metals.

Dave


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## rickzeien

philddreamer said:


> How does the solvent welding hold up to the acid?
> 
> 
> 
> 
> I haven't used any... for the water lines, I've used threaded couplings; the elbows are just fitted tight. They don't leak.
> For the drain valves, I use threaded valves and Teflon tape, so no "glue" either.
> 
> Phil
Click to expand...

Sounds like the right way to go. Not sure I would trust the solvant weld.

Sent from my SM-G950U using Tapatalk


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## philddreamer

Thank you, gentlemen!
I use LIQUID FIRE, it's 96% to 98%... I've found it at Ace Hardware, for about $25.00 /gal... they also have ROOTO, I don't recommend it... it has buffers and the acid will foam and makes things messy! 

A WARNING!!! Be very careful when there's foam on top of the acid while de-plating!!! If there's a spark while connecting or disconnecting the terminals and it reaches the foam, it will BANG!!! :shock: 
So use a face shield and safety gear!! 

I once bought some sulphuric from a chemical outfit, $50.00/gal! :? 
Needless to say, I now buy it at Ace! :mrgreen: 

Phil


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## Bertho

A followup on my questions about Sulfuric Acid and PVC compatibility.
I am testing compatibility of PVC and sulfuric acid at room temperature and at 65C.
I got samples of regular white plumbing PVC, gray electrical PVC, and a blue PVC piece from an 8" pipe.

The available sulfuric acid is very old and has absorbed some water. The density measured 1.74 = 81%
Both sample sets have been tested by now for 30 hours without any visible changes.
The acid on the hotplate presumably has been concentrated by now with water being driven off. Unfortunately the testing volume is too low for me to accurately retest the acid. (the test procedure requires 50ml). Regardless, I need to order some 98% acid.


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## kernels

Bertho, this is all secondhand information but . . . 

I have dealt a bit with a company doing E-waste recovery in reasonable volumes, like 6000L reaction chambers. I was surprised to see them using PVC pipes to transfer concentrated Sulfuric Acid around, was told that their chemists had OK'ed it, even though both myself and the guy I was talking to were dubious about it.


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## Bertho

An update to my post from July 21 On PVC testing.
It is now 5 days without any effect.
I bought the suggested Liquid Fire from Ace Hardware and very carefully measured the density @ 25°C = 1.823 That translates to 93%.
How do people measure higher % Acid? Looking at density charts, the highest density is at 97%
100% density,1.8255 is the same as 94% 
I am assuming my acid to be on the low side of the density peak since I doubt I received 100%.


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## snoman701

kernels said:


> Bertho, this is all secondhand information but . . .
> 
> I have dealt a bit with a company doing E-waste recovery in reasonable volumes, like 6000L reaction chambers. I was surprised to see them using PVC pipes to transfer concentrated Sulfuric Acid around, was told that their chemists had OK'ed it, even though both myself and the guy I was talking to were dubious about it.


Moving it around cold is one thing...consistent use at elevated temperature another.




Sent from my iPhone using Tapatalk


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## Bertho

I saw Phil's comment about filtering the acid and fine particles. I do not look forward to that phase. 
Is there an alternative? In my case, with a PVC cell, I will have a separate electrode. Could it be "bagged" to catch the particles? Basically the reverse of the bag for a silver cell. Or maybe a cup or glass under/around it to catch the particles.


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## Outlaw72

I just want to say, this thing is beautiful and I can only hope that one day mine is half as amazing as this. Phil, you did a great job on this, thanks a lot for sharing it with us.


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