# Info on sulphuric deplating/stripping cell



## darinventions (Nov 7, 2015)

Ok ill start off with please only comment if you have good knowledge & or experience with this type on cell..i am working on a new design of a stripping cell...i have a working cell an have been writing all of my info in a log book ...i need outside info to cross reference others experience with my own...my first question is how much run time do you generally get before it gets to hot....question 2 do you find any advantage using sulfuric with or without glycerine... question 3has anyone experimented with different voltages such as 8v/14v /6v&andwhat amperage did you use if you can remember ...i thank you very much for all your info and if anyone has any other good info to share that i didnot cover please post and explain...keep in mind that I'm using all info collected here for a new more efficient design of this cell


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## Geo (Nov 10, 2015)

1. Depends on amps, cell size and distance between anode and cathode. The higher the amps, the more heat is produced.The smaller a cell is, the faster heat builds.The greater the distance between anode and cathode, the less current will pass through the electrolyte.
2. Glycerin is not needed and can be dangerous if nitric acid is accidentally introduced. Glycerin and nitric acid in sulfuric acid makes nitro glycerin when heated. It was believed that the glycerin helped the gold precipitate which is not the case as it will precipitate as soon as the gold leaves the vicinity of the anode.
3. Voltage and amperage is determined by the size of the anode and cathode and distance between them. 12v at 10 amps will heat a 1 liter cell in about 15 minutes of continuous use if you are using an anode basket.


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## darinventions (Nov 15, 2015)

Thank you for the info GEO..the info on glycerine is very important for beginners or the experienced refiner that just didn't find any info about it during his or her search...ill admit i did not know that could happen an I've spent hours researching different random stuff that applies...as for the cell i think most all of them will be of the same size rather if it is a 1liter. or greater....but with my design that I'm working on there will be no need to have a cell that is larger than. 1 liter.... an the run time should increase to one hour +or-...


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## solar_plasma (Nov 15, 2015)

U=I•R

P=U•I

1 Watt over a time of 1 second ist equal to 1 Joule

1 Joule will heat 1g gramm of water 0,239 Kelvin

the heat capacity of water is 4,186 kJ/(kg K)

the heat capacity of H2SO4 is 1,386 kJ/(kg K)

So it will take about 3 times as much energy to warm up H2O compared to H2SO4 (for H2SO4 ~0,72 Kelvin per gramm per Joule)

If we use the cell (1 kg H2SO4) at let us say 40 Watts, it will get 0,0288 K warmer every second, 1,728 K every minute, 51,84 K in a half hour.

this is without calculating the loss of warmth, just as if we would use a thermal isolated container

Quite seldom I have to calculate anything else but water and I wasn't sure, if I could find out, but when I do the plausibility check and compare this result to what I have experienced, it seems to be just fine. 


One advice: everyone who wants to basically understand his cell, should have a look on Ohm's law! Just as Geo already said: The Ampere is always given by the setting of voltage and resistance. The resistance is given by the electrode areal, distance and composition of electrolyte.


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## g_axelsson (Nov 15, 2015)

solar_plasma said:


> One advice: everyone who wants to basically understand his cell, should have a look on Ohm's law! Just as Geo already said: The Ampere is always given by the setting of voltage and resistance. The resistance is given by the electrode areal, distance and composition of electrolyte.


And in the case of a sulfuric cell also of the electrode composition. When the gold is gone the passivation of the electrode surface increases the surface polarization that reduces the current. It can also be seen as the passivisation is decreasing the electrode area.

Göran


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## solar_plasma (Nov 15, 2015)

Göran, I am quite happy, that the severe look of the physicist didn't find any bigger mistakes, than this! :lol: Thank you for adding this important point!


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## darinventions (Dec 9, 2015)

Ok sorry for not posting on this sooner ..I've been waiting on a copper screen to come in that i ordered on ebay ..the dude forgot to ship it an it took twice as long to get it..anyway i did get to run it an it ran for 45 minutes an held a steady temperature of 57°F...i put all kinds of different gold plated items in with different types of base metals including steel ,bronze ,atonamy,bismuth,tin,an even a little ingot of solder that had some gold on the bottom of it... if you where wondering ..yes this unit is water cooled. an sealed ..i use a small water pump an have a little thermometer mounted on it to monitor the temp..i will be posting pictures of it later in the week ..i thank everyone that shared information pertaining to this ..


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## darinventions (Dec 9, 2015)

I forgot to mention that it only dissolved gold..all the base metals came out looking like new minus the gold plating


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## NobleMetalWorks (Dec 9, 2015)

darinventions said:


> Ok sorry for not posting on this sooner ..I've been waiting on a copper screen to come in that i ordered on ebay ..the dude forgot to ship it an it took twice as long to get it..anyway i did get to run it an it ran for 45 minutes an held a steady temperature of 57°F...i put all kinds of different gold plated items in with different types of base metals including steel ,bronze ,atonamy,bismuth,tin,an even a little ingot of solder that had some gold on the bottom of it... if you where wondering ..yes this unit is water cooled. an sealed ..i use a small water pump an have a little thermometer mounted on it to monitor the temp..i will be posting pictures of it later in the week ..i thank everyone that shared information pertaining to this ..



Water cooled and sealed? This type of cell produces hydrogen gas, which is highly explosive (refer to the Hindenburg accident). I hope you mean the water cooling is sealed and not the electrolytic cell. If the electrolytic cell is sealed, and close to any water source, you could not only create an explosion, but that same explosion might cause sulfuric acid to come into contact with water, and that I don't imagine would be a good day for anyone close by.

You are using concentrated sulfuric acid in a sulfuric gold deplating cell. If concentrated sulfuric acid comes into contact with water, it will spatter all over the place. The sulfuric acid evaporates the water so fast, that it will splatter far if it comes into contact. Personally, I would never use any sulfuric acid anywhere near water, regardless of how safe you think it might be. It reacts far too violently with water to take that kind of risk.

This is what happens at the anode when you put an electrical current through concentrated sulfuric acid. You are creating persulfuric-acid, Also called Caro's acid, permonosulfuric acid, etc. Under these conditions gold is soluble and the gold ions migrate into solution, as soon as the gold ions go into solution, the persulfuric acid immediately turns back into sulfuric acid and the gold drops back out of solution, finely divided. Once the gold has been stripped, the persulfuric acid attacks the base metals, creating an oxidizing layer and resistance to electrical current. This is the reason when using a car battery charger, you see a drop in the readings. Under these conditions you should never see base metal that looks like new. Not ever. Not unless you are doing something totally outside inorganic chemistry as we know it.

I have made several sulfuric cells. When I am using them, I will stop using one if it becomes hot, and use another. Switching off like this, I feel, is better than attempting to cool with water. I do use material that strips heat from the sulfuric electrolytic cell however. Jewelers use broken up pumice to quickly strip heat from metal. I took this idea and simply bedded the cells in the pumice to strip heat from the cell so I can run each longer, this also cools the cells down faster after use. In this way I not only can run the cell for longer periods of time, but also am not putting myself at risk.

One last note, I know I am repeating myself but I feel this must be included for those who might be new, reading this post, and wish to create a water cooled sulfuric electrolytic cell. Don't. There is no reason to use water to cool an eletrolytic cell. You can always use more than one cell, it's not worth putting your health at risk, or those near you. If sulfuric acid comes into contact with your eyes, it could blind you for life, or cause other damage as well. And never, ever, seal a sulfuric electrolytic cell, the hydrogen gas that builds up is highly explosive.

Scott


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## Harold_V (Dec 9, 2015)

While the problems of introducing water to sulfuric acid are well known, water cooled stripping cells are not unknown. I personally witnessed one in the mid 70's, operated by the US Government (in New Mexico). Published information of the time indicates that the government had recovered more than 35,000 ounces of gold by this method. The storage yard supported the claim, as there was a huge number of 55 gallon barrels of stripped components stored in the yard. 

The water jacket was open, as was the stripping cell proper, but the height of the water jacket was below that of the stripping portion of the cell. I can see how enclosing the water portion would be safer, but I certainly endorse the idea of a water cooled cell, in particular, if one has access to a respectable amount of material in need of stripping, as the cell can be operated non-stop, until it has accumulated a large volume of value. The cell in question was built accordingly. 

Harold


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## 4metals (Dec 9, 2015)

Phil made one with a closed cooling coil (closed to the sulfuric but open to ambient pressure) and posted great photo's here. http://goldrefiningforum.com/phpBB3/viewtopic.php?f=40&t=22603


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## darinventions (Dec 9, 2015)

Sorry i should have been more discriptive...The cell has a water reservoir that is sealed..the actual cell is set into an sealed to the top of the reservoir...Now i pressure checked it with a water pump that put out twice the volume an pressure than the one that will be used..i let it run for 48 hours straight an had no leaks. then it set for about 10 days full of water an didnot bleed off..meaning it didnot draw air ...As i said eairlier in my post i have a thermometer mounted in it to check temperature regularly ...I COMPLETELY understand the dangers of sulfuric an water..i went through a lot of trial & error to find what would properly bond everthing together .


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## darinventions (Dec 9, 2015)

I was gonna post pictures but they're no good..i will take more an post tomarrow...until then what you will see is a mini fume hood i made that the cell sits in..the platform is set at 5° angle going back to the wall in case of spills , there are two holes in the platform with hoses glued in to drain off any kind of spill into a 5gal. bucket...you'll see two clear hoses coming up from the water bucket into the cooling reservoir...next to the water bucket you'll see a glass jar with two lines..this is to siphon out the cell of all acid ...mounted on the side of the fumehood is a vacuum that operates the siphon...then of coarse no cell would be complete without a 12V-10Amp battery charger


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## darinventions (Dec 11, 2015)

Pics of the cell and fumehood...other items are a measuring cup an plastic tweeser


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## darinventions (Dec 11, 2015)

Well these are all the pictures..the only upgrades i plan to add would be a triple gang box for light switches..one for exhaust fan/one for siphon vacuum /an one for battery charger... I'm gonna get a little LED light to place behind the cell in the hope to be able to monitor saturation of solution


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## Grelko (Dec 11, 2015)

That is a nice compact fume hood you have there. Do you happen to have a diagram of it, or is it on the site? I should make one, but never have the room for it. This size would be perfect after moving a few things around.


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## darinventions (Dec 13, 2015)

Anyone interested in making anything I've made will be able to find it on( build your own equipment ) after the first of the year. I've got lots of NEAT STUFF that will save a lot of money an the best part is it all works very well..i use this stuff all the time ...so keep a watch on that portion of the forum after the first ...


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## darinventions (Dec 13, 2015)

I feel as though i should comment on the exhaust fan. this is a BRUSHLESS FAN from an old computer tower..why brushless? because while using anystripping cell hydrogen gas is created,and hydrogen gas is EXTREMELY FLAMMABLE..while a electric motor that has brushes will make a spark which could ignite this hydrogen gas..a BRUSHLESS MOTOR does not make any spark


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## solar_plasma (Dec 13, 2015)

Though I can hardly imagine that you will reach the LEL of hydrogen (4vol%) in a well ventliated room, this might become possible in your case (as far as I understand your setup). If so, the hazmat squadleader in me is alarmed as your construction is far from beeing explosion prevented. You have a lot of areals that might get charged with static electricity, all the more there are rotating plastic parts (the pc fan). And you have a wonderful ground/earth in your cell. So, there is in fact everything needed to blast this construction - I hope you're wearing ear- and faceprotection :lol: 20% of that volume would be enough to give you a hearing damage. 

Well, you might be lucky all the time, but I would not feel very safe with it.

https://en.wikipedia.org/wiki/Flammability_limit


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## solar_plasma (Dec 13, 2015)

Btw it looks very nice! Good work!


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## darinventions (Dec 14, 2015)

Thanks Bjorn...about the static related discharge..i don't think it will be much of an issue ..i live in Missouri an its very humid here most the time..but i know there's other parts of the world where this would be a issue...so how do you propose you would address a static issue?


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## solar_plasma (Dec 15, 2015)

That would be more a question for Göran or Richard to answer as they know much more about electricity than me. But based on the methods, education and equipment in the hazmat team I can say everything that is a good conductor AND is grounded so everything has the same potential is considered to be safe - well some kind of minimum safety. Plastics have to be anti-static. Electrical equipment has to be marked as being explosion prevented. Now, this is for areas where the LEL might be exeeded for shorter time (like a hazmat operation). Further we measure the concentration of flammable gases all the time using an "ex-warn" that will give an alarm as soon as the LEL is reached based on a toluol standard just to be safe in any case. Areas, where the LEL is exceeded ALL the time are something else!

I think the better and safer way is definitively to prevent to reach the LEL of 4% by blowing lots of air INTO the box and lead it directly to the outside. It has to be secured, that this ventilating is provided at any time, it might make sense to have a redundant system with more than one fan or a security circuit that will cut the cell circuit in case of malfunction.

Much easier just to use it under an open fume hood in a well ventilated area :lol: or not to close the box you have build while operating. And to observe the process, to control temperature all the time and not leaving it unattended.


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## darinventions (Dec 16, 2015)

Ohh...now i see why the concern over hydrogen gas build up...to clear things up i never completely close the lid while in use(its a two piece lid)the lid is really jusr to keep dust and bugs out while its not in use...i also always siphon out the acid when I'm done using it regardless of how much values it may contain..i figure if its sealed in a jar it can't draw moisture from the air or get anything else in it...i try my best to make everything safe ...an just about everything involved in recover an refining_can either hurt you or kill you if you don't keep safety in mind ...with that being said for any new guy's that read this please do your research before just diving in blindly ..there's NO AMOUNT OF GOLD WORTH YOUR LIFE!


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## butcher (Dec 17, 2015)

I would recommend using GFCI outlets in your lab.


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## darinventions (Dec 18, 2015)

Got'em just haven't put them on that side of the room yet...other side of the room is all GFCI receptacles...i also use plug in timers..they'll handle a single burner hot plate with no problem most of the timers I've found are rated for. 1500+ watts.. make sure you check for max amps or watts before buying..if its not rated for at least 15Amps or above 1400Watts don't get it ..


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## darinventions (Jan 9, 2016)

I probably should have waited an ran some more plated material before recovering the gold from the sulfuric solution but anyway here's my first bar from this cell..weighs 16 grams ..


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## colt45gto (Jan 9, 2016)

nice setup great result. how much of what did you strip for that beauty?


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## darinventions (Jan 17, 2016)

In the last picture you'll see a French Onion Dip can on top of a Coffee can..dip can was full of magnetic an nonmagnetic jewelry(none containing silver ) but all was gold tone ,plated,clad,1/10th,filledor in some way had gold on it...the coffee can was full of gold plated spoons ,forks ,knives ,a zippo,a few tea or coffee stir sticks,&a 24k plated air plane i bought at flee market for $1.00(it was 5"long ,6"wide,3.5"tall)had to cut it up..it took me about 1.5hours to run it all through the cell... then i dissolved it in hcl+bleach&precipitated with SMB..then melted it. if you want to know how much i couldn't tell ya i forgot to weigh it or take any pictures ...SORRY guys..


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## Rachello (Jul 24, 2018)

Hey guys!

I just wanted to add that I think this is a great thread!! Although I haven’t checked the math I really think this tidbit is very informative. I have read so many questions from people asking this exact same thing. It’s good to see the facts behind the answers!



solar_plasma said:


> U=I•R
> 
> P=U•I
> 
> ...



But in reality the whole thread & it’s posts are really informative & straight to the point  

Rachel


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## nickvc (Jul 25, 2018)

Rachel it’s almost impossible to post false information here on the forum as we have far too many clever chemists and refiners that can spot it in an instant, thank you all, and most threads get fully dissected by one expert or several if it doesn’t sound right, we try to keep fantasy and dreaming off the forum for the safety of all.
As for the sulphuric cell in my opinion one of the most dangerous pieces of kit we use, I hate sulphuric as much as I do hydrofluoric, I’d rather use cyanide but for those that cannot source it the cell offers a workable alternative but please always work with your own safety in mind.


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## anachronism (Jul 25, 2018)

Yeah- if Solar Plasma posted that it will have been triple checked before he even hit the submit button. Bjorn's like that 8) 8)


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## bengie84 (Jul 22, 2019)

I what to do a cell for all my pins and plated scrap however all I see is sulphuric acid being used here in England that’s a BIG no no and is a criminal offence to even try to buy it let alone be in possession of it.

So how or what else could be used in its place I played around with salted water but far to slow and have kilos of pins to get through 

Any thoughts or info would be greatly appreciated


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## kernels (Jul 22, 2019)

There are some things in life that are just not meant to be. Looking around for ways to do recovery and refining with stuff you can find in the pantry is pretty much a waste of time. 

It is technically possible to evaporate battery acid down to get concentrated Sulfuric.


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## rickbb (Jul 24, 2019)

bengie84 said:


> I what to do a cell for all my pins and plated scrap however all I see is sulphuric acid being used here in England that’s a BIG no no and is a criminal offence to even try to buy it let alone be in possession of it.
> 
> So how or what else could be used in its place I played around with salted water but far to slow and have kilos of pins to get through
> 
> Any thoughts or info would be greatly appreciated



So everyone in England that owns a car is hauling around a half liter of banned substance called a battery?


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## bengie84 (Jul 24, 2019)

Pretty much yeah we can’t even buy diluted to top batteries up all because some women had it thrown in her face but now big celeb so her plan worked but screwed the rest of us responsible Englishmen


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## anachronism (Jul 24, 2019)

bengie84 said:


> Pretty much yeah we can’t even buy diluted to top batteries up all because some women had it thrown in her face but now big celeb so her plan worked but screwed the rest of us responsible Englishmen



Chucking the baby out with the bathwater by enshrining knee jerk reactionary laws has been a trademark of recent UK governments.


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## FrugalRefiner (Jul 24, 2019)

While I'm more in tune with comments regarding U.S. politics, we should probably avoid posts about the politics of other countries as well. I'm sure there are those on both sides, and we don't want to discuss issues that might divide our members.

Dave


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## kernels (Jul 24, 2019)

bengie84 said:


> Pretty much yeah we can’t even buy diluted to top batteries up all because some women had it thrown in her face but now big celeb so her plan worked but screwed the rest of us responsible Englishmen



You don't have to buy diluted Sulfuric for topping up batteries, just buy a few oldish batteries and empty them out. Obviously look for ones that have the little access holes on top where you can just unscrew a plug and drain them. 

Obviously you still then have to concentrate it down, which I would't say is trivial, but certainly achievable if you have no other choice.

The empty batteries can then obviously be filled up with water and sold on to the scrap metal guys (who buy them for the Lead anyway)


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## anachronism (Jul 25, 2019)

FrugalRefiner said:


> While I'm more in tune with comments regarding U.S. politics, we should probably avoid posts about the politics of other countries as well. I'm sure there are those on both sides, and we don't want to discuss issues that might divide our members.
> 
> Dave



Thanks for the input Dave noted and understood. That given, it's a general observation rather than a partisan one. Benji and I would probably agree on it even if we were diametrically opposed in political beliefs. There's a very big movement of "they're all as bad as one another" here. 8) 8) 

Onto refining.


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## bengie84 (Jul 30, 2019)

I agree also and not many ppl like there gov no matter where they live but yes I do have a few all batteries that tried to drain just don’t have a distiller but I’ll keep trying and hopefully sort it


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## kernels (Jul 30, 2019)

Do some more research, I don't think you 'need' a distiller, my (untested) understanding is that all you have to do is evaporate off the water, H2SO4 boils at a very high temperature. You want to do the opposite of distillation.


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## FrugalRefiner (Jul 30, 2019)

I question the idea of using the electrolyte from old batteries. As I understand it, a new battery starts out dry, and the sulfuric (sulphuric) acid is added as the electrolyte. It produces power by the reaction between the plates and the acid, and in that process the acid is "consumed", though it is a somewhat reversible reaction when the battery is charged during operation of the vehicle.

So "oldish" batteries that are no longer useful to start our cars don't really have much sulfuric acid left that can be reclaimed for a stripping cell.

At least, that's the way I understand it.

Dave


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## butcher (Jul 30, 2019)

when the battery plates are in good shape, and the cell is charged, most of the sulfuric acid is in solution with the water, as the cell discharges, the plates sulfate leaving a higher water content, a dead cell will just be mostly water, lead sulfate, and lead sulfites.


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## bengie84 (Aug 3, 2019)

Hey guys after draining one battery and doing a bit of research yes you can just boil of the water.
I tested the acid with a ph meter reading .2 so this battery was a good one others have been upto 5.0 so next step to boil if the water and see what happens 
Nothing ventured nothing gained


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## butcher (Aug 3, 2019)

Have you measured the specific gravity of the acid? specific gravity of the acid would be more of an indicator of concentration.


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## bengie84 (Aug 4, 2019)

butcher said:


> Have you measured the specific gravity of the acid? specific gravity of the acid would be more of an indicator of concentration.



After a lot of research trial and error trying to weigh one g/ml (massive ball ache) I got the weight upto 1.458g per mil so heading in the right direction to achieve the 1.8g per mill for Concentrated solution but trying to measure out and exact amount blood hard lol


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## anachronism (Aug 4, 2019)

https://pksafetyuk.com/sulphuric-acid-drain-cleaner-1-litre


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