# Electrolysys Sulphuric cell



## Kalf999 (Dec 21, 2009)

About Steve's video about the Sulphuric Cell....

The material for cathode and anode is very well explained.

What I miss on the forum is a table where I can find :
-Volume of the cell
-DC-Voltage
-AMP's
-Quantity of Gold Plated Items ?

In other words , I built 1000 Milliliter (H2SO4) Cell. 
Which Power Supply I should use , at which Voltage and AMP'S?

An electric cell seems so important, that I am suprised that there is not 1 specific topic about it....

Best regards, Frans Kalf


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## samuel-a (Dec 21, 2009)

the volume of the cell is your desire.
with 1000ml you should do just fine with 9-12 volts.

the Amps will change by it self according to the amount of matirial processed each time...
just make sure you have that possibility in your transformer (9-12V , 10 Amp max)

Quantity... well... they say 12-14 hours of net stripping time....
that's a lot of material.... belive me...

Good luck
SAMUEL


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## goldsilverpro (Dec 22, 2009)

The sulfuric cell can be made in many different ways, using many different materials. Rather than giving an exact, cut-and-dried setup, I think it's better to first get an understanding of how it works. Then, you can adapt this knowledge to your particular situation. This subject has been covered many times on the forum in great detail, especially in the early days. I would suggest that you use advanced search. An example of keywords you could use are: sulfuric cell cathode. Where it says Search for Author, type in the name of a person that has been involved in most of the sulfuric cell discussions. Two that come to mind are myself, goldsilverpro, and lazersteve. There are many others that have contributed excellent information to these discussions but, when the subject comes up, one or both of us usually gets involved. In general, this is what you need to know:

(1) Sulfuric acid. The strength should be at least 90%, by weight. Battery acid (about 35-40% H2SO4) won't work unless you first evaporate the water off by heating - the weaker acid will dissolve copper and other base metals very rapidly. If you start with a strength of 95-96%, it helps the stripping speed to add about 5% water, by volume, Always add the acid to the water. Don't add any glycerin - it's not needed.

(2) A container. This can be made of glass, certain types of plastic, or mild steel. Don't use stainless steel.

(3) A Cathode. Steve uses a slab of lead. I always used a mild steel tank to hold the sulfuric and made the tank, itself, the cathode (-).

(4) Anode (+). The parts you are stripping are made the anode. For large pieces, you can clip the parts and put them in the solution. For small parts, such as pins, Steve has designed a copper screen basket. Someone on the forum developed a small tumbler to hold and move the parts around. A tumbler works best.

(5) Amperage. The amperage is what does the stripping. The more amps, the faster the stripping. However, the more amps, the hotter the solution becomes. The hotter the solution, the more attack you will get on the base metals. This can cause big problems. In my opinion, overheating is the cause of most of the problems that people have had with this solution. For this reason, for your small 1 liter bath, I would use a maximum of 2 or 3 amps. I like to keep the solution under 120F and control it by adjusting the amperage. If you use a plastic tank, monitor the temperature closely to keep from melting or softening the plastic. You could use more amps if you keep the solution cool. I haven't done this, but you could probably place the tank in an ice water bath or a large cool water bath.

(6) Voltage. It doesn't make much difference what the voltage is. Control the amperage and let the voltage fall where it may.

(7) What happens. As the gold strips, the amperage drops. When the amps fall to zero, the gold is completely stripped. The gold forms in the solution as a black powder. At the end, when the amps approach zero, I usually increase the voltage. The amps will go up a bit and then finally drop back to zero. With a good setup, normal gold plating should strip in a few minutes.

At some point, there will be so much black powder that it will cause a partial short and the amps won't go to zero. At this point, it is time to harvest the gold. You can remove the electrodes and allow the powder to settle in the form of a sludge. Carefully decant (pour) the solution off of the sludge. The solution can then be re-used. If a little sludge is poured off with the solution, don't worry about it - you'll get it next time.

After decanting, pour the sludge into about 7 to 10 times it's volume of water. Let the gold settle and decant or siphon off the solution. Rinse the sludge a few times. Collect the sludge and dissolve it in a minimum amount of aqua regia and refine as normal.

(8) Safety. Working with strong sulfuric can be very dangerous, since it can quickly and severely burn the skin. Always use rubber gloves and a full face shield. Work slowly and carefully. Think before you do something.


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## samuel-a (Dec 22, 2009)

Great post chris !

just one thing that i belive is missing, incineration before dissolving... i have learnd it the hard way that it's very much needed....


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## goldsilverpro (Dec 22, 2009)

> just one thing that i belive is missing, incineration before dissolving... i have learnd it the hard way that it's very much needed....



You're probably right. I just never did any incineration on anything and really don't think I lost any values in this case. Harold has almost made a believer out of me, however. Were I to refine again, I might try incinerating certain things.


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## goldsilverpro (Dec 22, 2009)

Here's the excellent thread on the tumbler that firewalker made. The links seem to still work. One of the videos locked up firefox - I used the back button while it was still loading, so it was probably my own fault. Maybe Ralph will volunteer to grab all that stuff off of photobucket while it's still available. 

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=40&t=5092&hilit=sulfuric+tumbler


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## samuel-a (Dec 22, 2009)

well, you probably didn't loose any value but i wonder that it's effecting the following dissolving and rinsing later on.

whan i did my first batch that came out of a cell, without incinitarion of the powder, the AuCl3 was very dirty and left me with a very golden/yellow solution after dropping and was negative for gold... at the time i didn't know what happen and thought the i had a problem... but the simple fact was that my AuCl3 was just dirty...

when dealing with the powder from the cell rinse water (where i dipped the pins after stripping), this one i did incinerate, wash well after (water , acid) and the AuCl3 was very very clean and clear after dropping...

whan incinerated, i had to leave my shop for a few minuts dou to the amount of of smoke and smell of sulfur (gun powder like smell).


BTW, i wonder if i could incinerate in a watch glass... will it hold?


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## goldsilverpro (Dec 22, 2009)

> well, you probably didn't loose any value but i wonder that it's effecting the following dissolving and rinsing later on.


I'm not going to get into this in detail because I think most of you are better off following Harold's methods. They involve more steps than mine, but they are more step-by-step and they work every time for most everything, if you follow them. My procedures are different and they can vary slightly depending on certain variables in the makeup of the material. As far as gold from the sulfuric cell is concerned, I have refined many 1000s of ounces from it with a purity of at least 9995 (and often, 9999) without incineration or evaporation. To do this, I had to master the art of raising the purity of slightly off-purity gold by flux melting. Every professional refiner develops his own methods. The end results are the same - at least 9995 gold. The proof is in the pudding and, in this business, there is always more than one way to skin a cat.


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## samuel-a (Dec 22, 2009)

Dear chris

i didn't ment to question you final gold product,i apologize if it seems that way.
i assumed that you have your own methods of reaching >99.95%

but as you say, for small timer like me and a lot of others here, inciniration is the way to go...


SAMUEL


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## Harold_V (Dec 23, 2009)

samuel-a said:


> BTW, i wonder if i could incinerate in a watch glass... will it hold?


Highly unlikely. If you prefer to not use a stainless container, a fused quartz evaporating dish would serve perfectly well. They are not cheap. 

Harold


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## goldsilverpro (Dec 24, 2009)

You definitely can't apply much direct heat to a watchglass without it breaking. I used to occasionally evaporate small 5 ml samples of acid gold solutions on a watchglass and then scrape the residue into a crucible for assaying. I evaporated them on an asbestos sheet on a warm hotplate. If I used too much heat or, if I didn't use the asbestos sheet, they usually broke. You might be able to use indirect heat in an oven, but I doubt it. If I tried that, I would use the thin type watchglass rather than the thick variety. Why would you want to incinerate in a watchglass, anyhow?


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## samuel-a (Dec 24, 2009)

well...
when ever changing a vessel i loose some matirial that is bonding to the bottom...
with watch glass it doesn't.... and if it is, it's vey easy to scrape it of...


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## Palladium (Dec 24, 2009)

goldsilverpro said:


> Maybe Ralph will volunteer to grab all that stuff off of photobucket while it's still available.
> 
> http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=40&t=5092&hilit=sulfuric+tumbler



I've got the video and i'm working on the rest. 8) 

http://www.youtube.com/watch?v=xgVPWmTFGFg


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## Kalf999 (Dec 26, 2009)

Hello GSP, Thanks very much for your explanation..!
I think you listed all items I needed to know ;-)

I have got a new container with 70's & 80's scrap, so the first week I will be depopulate boards en so on .. ;-)
In the mean time I will set up my Sulphuric cell and try them on a small batch to practice a little.

Again, thanks very much !

GSP & all contributors for this topic, Have a nice X-mas and a Happy New Year !


Frans Kalf, The Netherlands


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## Palladium (Dec 30, 2009)

Firewalker pictures :arrow:


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## goldsilverpro (Dec 30, 2009)

Thanks, Ralph


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## plamenppp (Jan 27, 2010)

I have a nice question too. I think to make my own cell tomorow but the temperature outside is -15 C sub zero. I have 96% H2SO4 and an old battery charger - 12V and 3A. The material is about 500 pieces of transitors with removed steel hats/caps and 2 of the 3 legs (only one of the legs is attached to the gold plated "base" with no plastic "eye"). Will it work?


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## goldsilverpro (Jan 27, 2010)

The one leg that's connected will strip. The other 2 probably won't. Sometimes, stuff in the general proximity will strip even though it's not connected. 

Personally, I think this is a very bad idea. You'll end up leaving much of the gold on the part. To get the rest of the gold, you'll have to go through nitric, or one of the other methods, anyhow. Why not just go in nitric to start with? Use the method I outlined to Arthur in the link I gave you.


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## plamenppp (Jan 28, 2010)

It is cold outside - very cold. The nitric will heat the dish and the heat may break it. There are fumes and I will have to use a lot of nitric. Moreover I'll have to collect the gold foils somehow and they are very very thin (they've been made during the era of the "golden breadth"). I'll have to collect the plastic "eyes" as well. There will be a lot of dirty work. I prefer to worl clean. And for the gold that will not strip - I will keep it for better times when the gold price is extremely high. Now I am interested will it work in the sub zero temperatures.


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## goldsilverpro (Jan 28, 2010)

I did notice that, from your last photo, the chips are tiny. Maybe, therefore, you'll get most of the gold in the stripper.


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## plamenppp (Jan 28, 2010)

So, do I have a green light to start?


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## goldsilverpro (Jan 28, 2010)

> So, do I have a green light to start?



Sure. Probably, the only thing you won't get in the sulfuric stripper is that from the 2 legs that don't make contact and the gold underneath that tiny, tiny chip. Although a lot of labor, you could twist the legs together just enough so they all make contact. Considering the size of the chip, I wouldn't expect as much gold as Arthur got from his stuff. The gold is probably fairly thick, though. Were these made in the U.S., I would guess the gold plated area to be worth about $0.08 per square cm, more or less. Are you making contact to the area under the chip or that one live leg? Is that one live leg actually electrically connected to the pad under the chip or is it just connected because of the bonding wire going to the post? Before starting, you might break the bonding wires on one and then use an ohmmeter to see what's actually connected to what. Just some ideas.


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## plamenppp (Jan 28, 2010)

goldsilverpro said:


> > So, do I have a green light to start?
> 
> 
> . Are you making contact to the area under the chip or that one live leg? Is that one live leg actually electrically connected to the pad under the chip or is it just connected because of the bonding wire going to the post?



It is electrically connected to the pad. These transistors are made in Bulgaria. I know there are Russian analogs as well but I can not find any. They've probably been stripped long time ago from someone more experienced.


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## YOYODIDU (Mar 11, 2014)

Hello everyone this is my first time at this wonderful. forum GSP've done a great job and detailed that someone like me can figure out how to do it right. I need some help please. 
After melted the gold over the pins. How can you pick up the black powder from the bottom of the tank with sulfuric acid. Without sprying  acid everywhere. 
Is it possible to collect the powder by electrolyte it???


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## bmgold2 (Mar 11, 2014)

YOYODIDU said:


> Hello everyone this is my first time at this wonderful. forum GSP've done a great job and detailed that someone like me can figure out how to do it right. I need some help please.
> After melted the gold over the pins. How can you pick up the black powder from the bottom of the tank with sulfuric acid. Without sprying  acid everywhere.
> Is it possible to collect the powder by electrolyte it???



If I understand your question, you want to separate the black powder from the sulfuric acid in the stripping cell.

On page 1 of this thread goldsilverpro states,


> At some point, there will be so much black powder that it will cause a partial short and the amps won't go to zero. At this point, it is time to harvest the gold. You can remove the electrodes and allow the powder to settle in the form of a sludge. Carefully decant (pour) the solution off of the sludge. The solution can then be re-used. If a little sludge is poured off with the solution, don't worry about it - you'll get it next time.
> 
> After decanting, pour the sludge into about 7 to 10 times it's volume of water. Let the gold settle and decant or siphon off the solution. Rinse the sludge a few times. Collect the sludge and dissolve it in a minimum amount of aqua regia and refine as normal.



Basically all you need to do is allow the powder to drop to the bottom of the cell (which could take a day or longer) and then carefully pour (decant) off the acid, trying to leave as much powder as possible in the bottom, and then pour off this sludge into 7 to 10 times as much water. *Pour the acid slowly into the water...Never pour water into acid, especially the concentrated sulfuric acid used here.* Once the acid is more dilute, the powder will settle much easier and you should be able to decant that acid off the powder. 

Do some searching on this forum for ways to concentrate the diluted acid to reuse it in the cell and how to clean up the powder you get from it. I personally don't feel comfortable heating the acid to concentrate it so I have just saved it to use for other things. Concentrated sulfuric acid is some dangerous stuff, HOT concentrated sulfuric acid is even worse. Make sure you understand all the possible dangers and wear protective clothing (gloves, eye protecting, etc.) if you attempt this.

You might also want to search for "fiberglass chamin plug" on this forum. That would allow you to filter the concentrated acid without diluting it and then the acid could be reused with no further concentrating and the fiberglass plug can be processed in the acids directly to recover the gold. The plug can even be reused once you are done. Again though, be careful. If you get even a drop of this acid on your skin you will know it.


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## goldsilverpro (Mar 11, 2014)

YOYODIDU said:


> Hello everyone this is my first time at this wonderful. forum GSP've done a great job and detailed that someone like me can figure out how to do it right. I need some help please.
> After melted the gold over the pins. How can you pick up the black powder from the bottom of the tank with sulfuric acid. Without sprying  acid everywhere.
> Is it possible to collect the powder by electrolyte it???


I don't understand what you mean by, "After melted the gold over the pins." I assume you mean, "when the gold on the pins has been removed." 

After the solution is completely settled, I carefully remove as much solution as possible without disturbing the black powder. This can be done by slowly pouring off the solution. If the vessel is too full to safely do this, you can slowly dip as much solution out as possible and then pour off the rest, leaving the powder in the container. The remaining powder/sludge is poured carefullyinto at least 5 or 6 times more water than sludge and stirred. It will get quite hot. After cooling, filter and treat the sludge with AR.

You can't use paper filters to filter the sludge before dilution because the strong sulfuric will destroy the paper. There are posts on the forum that indicate success with other filter media besides paper. It would be desirable to do this, since all the strong sulfuric obtained from pouring off and filtering can be reused in your cell.

I might mention that it's not necessary to collect the gold after each batch of parts. I wait until the gold powder builds up to a point where it causes a partial short. The amps, therefore, do not return to zero after complete stripping. When you see this happening, it is time to stop stripping and harvest the gold.

NOTE: While writing this, bmgold2 made an excellent post that summed up the procedure in more detail than I gave.


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## YOYODIDU (Mar 11, 2014)

bmgold2 said:


> YOYODIDU said:
> 
> 
> > Hello everyone this is my first time at this wonderful. forum GSP've done a great job and detailed that someone like me can figure out how to do it right. I need some help please.
> ...



Thank bmgold2 helped me a lot., I really terrified sulfuric acid.


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## bmgold2 (Mar 11, 2014)

YOYODIDU said:


> Thank bmgold2 helped me a lot., I really terrified sulfuric acid.



Glad it helped. I mentioned on this forum before that sulfuric acid scares me but then decided to call it a healthy respect. Just be careful and wear acid resistant gloves and glasses. It wouldn't hurt to keep some clean water around to quickly wash off any acid that gets on you. You probably already know this but, don't wear good clothes when working around sulfuric acid. You might not even notice it until they go through the washing machine but even weak battery acid can put holes in your clothes.


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## YOYODIDU (Mar 25, 2014)

samuel-a said:


> Great post chris !
> 
> just one thing that i belive is missing, incineration before dissolving... i have learnd it the hard way that it's very much needed....



Hello everyone I have a few questions about "Sulphuric cell"
1 is it possible to reverse the process and collect the gold powder by electrolysis
2 How to make incineration of gold? And at what stage
3 What is black powder floating with gold in sulfuric acid tank


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## nickvc (Mar 25, 2014)

1 I assume you mean can you plate the gold out instead of having to filter it, not in the sulphuric cell, simply allow the powders to settle decant very carefully to remove as much as possible of the acid, slowly dilute the remaining solution and then filter to recover your powders,that's your gold and other base metals.
2 the next stage is incineration, heat your recovered powders to a red heat, allow to cool and then place the incinerated powders in your beaker, add hydrochloric and heat, this removes many of the troublesome base metals, several treatments might be needed until the acid remains clear.
3 I think I answered this question above but gold in small particles rarely looks like gold but as a back to brown powder or particles.

One point make sure you keep your sulphuric covered when not in use it's very water hungry and also keep it concentrated or else it will dissolve a lot more base metals.
Good luck.


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## butcher (Mar 25, 2014)

YOYODIDU,

Remember if you wash the gold sludge powders or dilute the concentrated sulfuric acid, you should do this by slowly pouring them into a volume of water.

Never put water into concentrated sulfuric acid, it can generate so much heat it will boil the water, and can splash or spit concentrated acid back at you.

Acid into water, never pour water into concentrated sulfuric acid.

The better you study a process you plan to use, the better you will understand that process, and the less likely you will have troubles with it, the more success you will have. The less likely you will lose your values in the process, and the easier it is to troubleshoot a problem if one does occur.


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## necromancer (Mar 25, 2014)

safety first please

this link contains photos of a graphic nature.

http://www.dailyecho.co.uk/news/8253292.My_face_melted_when_drain_cleaner_exploded/


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## YOYODIDU (Mar 25, 2014)

thank you all for helping me . i have milion things to ask you .


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## nickvc (Mar 25, 2014)

YOYODIDU said:


> thank you all for helping me . i have milion things to ask you .




No you have a million things to use the search function for, it's the top right of your screen.
Sorry but we don't hold your hand here you read and learn or burn, it's tough love but for a good reason we don't get paid to advise you or anyone else, if you want to pay good money we have members who can help otherwise it's up to you 8)


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## YOYODIDU (Mar 26, 2014)

Thanks again for all the help and generosity 8)


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