# Help with reverse electro plating



## Mouchman

so i've decided to try my hand at reverse electroplating to consolidate my scrap gold before purifying with AR, i figured it would be the easiest way next to nitric acid to isolate the gold. Ive been fingering through the forum looking for ideas for setups and procedure and i think i may have something.

i set up an old car battery charger with a 2/10 amp selector with alligator clips, i have a glass casserole dish, a 8 inch stainless steel rod, and im using drain cleaner made of potassium hydroxide (KOH) as an electrolyte solution and my scrap is gold plated copper pins recovered from commercial grade PCB's, with what appears to be either solder or nickel plating underneath the gold.

my procedure was simple, pour the solution in the dish, select the 10 amps, connect the negative lead to the stainless steel cathode, and the positive lead to the pins on the anode.

now my problem is the anode. for my first attempt, i actually used vinegar as a solution just to experiment the setup, and i used a flattened copper pipe as my anode.

after leaving the cell running overnight, i checked it in the morning and it seemed that somthing had worked. the stainless steel rod was covered in black sludge and there was also residue on the bottom of the dish. but upon closer inspection, the pins were untouched and it looked like i had done nothing more then copper plate the rod. so i cleaned the set up and repeated with a new anode and the KOH as the solution.

for my second anode, i took a 2inch x 5 inch x 1/8 inch copper plate and placed the gold pins on that and repeated the process. however the results were similar, copper plated rod.

for my third run, i switched to a stainless steel shower drain cover, so it made a nice little basket for the pins. however, after leaving this one for a only a half hour or so, i checked the progress and the bottom of the drain had been dissolved and the gold remained untouched.

now i also tested clipping the positive lead directly to a pin and after a minute, the gold had reverse plated, so i know that that method works, but i have over 6 coffee cans full of pins and this would be way too time consuming to do each pin.

so my question is, what type of anode setup should i be using to get the biggest batch i can get with out polluting the recovery as much as possible?

any help on the matter would be greatly appreciated


----------



## lazersteve

Get some copper mesh from my webstore and keep the temperature down and water out when using it.

Steve


----------



## Mouchman

is copper mesh the only option? because after my first two attempts, im not too keen on using copper if i can avoid it


----------



## lazersteve

Copper is very resistant to warm concentrated sulfuric acid.

If the acid becomes hot or diluted then the copper will corrode away.

Have you read any of the posts related to keep your sulfuric cell running smoothly? 

Have you been on the Guided Tour?

Steve


----------



## Mouchman

i have read through some of them, but i thought my problem was the anode, not the electrolyte, so i guess i was searching the wrong thing

is H2SO4 better to use then KOH? i thought KOH was a better electrolyte?
and no i haven't been on the tour yet

thank you again for all your help


----------



## ericrm

we pretty much all use concentrated sulfuric here 
sulfuric dont disolve too much copper when you keep it concentrated and cold,also you can reuse the sulfuric acid by just boiling it down ,saving money.....
for KOH i dont know many poeple who use it for gold pin,you might have found a good way to remove copper from pin,but it is more fast to remove gold from pin...
BUT i read a guy who have used table salt....
your probleme is that here anybody know about sulfuric cell but not many about KOH

BY THE WAY KOH IS A REAL DANGEROUS STUFF ,I HAVE WORKED WITH IT AND IT MAKE HOLE IN YOUR SKIN WITHOUT YOU FEEL9ING IT... WEAR A FULL FACE OR MINIMALY GOGGLE ... ONE PIN HEAD DROP IN THE EYE WILL GET YOU IN A REALY BAD POSITION

have fun


----------



## steyr223

Potassium hydroxide 
sodium hydroxide & Sodium hypochlorite are for removing the material that covers the circuit board everywhere except where it is to be soldered known as a solder mask.
The reason for this is to allow your solution to get at the gold trace or gold plating the mask covers when is dissolving your base metals
When running a cell definitely use concentrated sulfuric acid 
Now steve shows the lead anode and the lead cathode in his video this gas changed I take it.could someone explain
thanks steyr223


----------



## lazersteve

Read through the Guided Tour throughly and pay special attention to the Reaction List in the Sulfuric cell section (#6). There is a link near the photo of the dried black powder called 'Cell Information'. While you are there read the link below it titled 'Black Powder from the Cell'.

Steve


----------



## lazersteve

steyr223 said:


> Now steve shows the lead anode and the lead cathode in his video this gas changed I take it.could someone explain
> thanks steyr223



The anode is made of a *steel* rail and whatever type of contactor you want to use to connect to your gold plated material (copper clips or copper mesh). The only *lead *(Pd) electrode is the negative lead (cathode).







Steve


----------



## Franciz

Dear All, 

I am trying to use reverse electro plating cell for gold pin for the first time.
I am using a 6V 7A battery charger, Lead cathod and copper mesh with 98% sulfuric acid in a 1L breaker.
Now i have problem, The problem is the gold strip out from the pin in flake form(not in black powder form) and also copper is dissloving and stick on my lead cathod Acid Turn Green/Blue. The acid is not hot.

I did not saw any black powder but only tiny gold flake, Lead cathod full of copper. What actually did i go wrong?

I have also try out 6V and 12V battery charger but in difference current but the result is still the same.
Please help me out....
Thanks........


----------



## Geo

it sounds like you are using the wrong acid. if you are sure its sulfuric acid then its been diluted and its dissolving copper.


----------



## Barren Realms 007

Franciz said:


> Dear All,
> 
> I am trying to use reverse electro plating cell for gold pin for the first time.
> I am using a 6V 7A battery charger, Lead cathod and copper mesh with 98% sulfuric acid in a 1L breaker.
> Now i have problem, The problem is the gold strip out from the pin in flake form(not in black powder form) and also copper is dissloving and stick on my lead cathod Acid Turn Green/Blue. The acid is not hot.
> 
> I did not saw any black powder but only tiny gold flake, Lead cathod full of copper. What actually did i go wrong?
> 
> I have also try out 6V and 12V battery charger but in difference current but the result is still the same.
> Please help me out....
> Thanks........



I think if you will lower your voltage and current you will solve part of your problem.


----------



## Franciz

Geo said:


> it sounds like you are using the wrong acid. if you are sure its sulfuric acid then its been diluted and its dissolving copper.



I am using sulfuric acid 98%, I brought this in battery store.
How can i tell if it is begin diluted?


----------



## Franciz

Barren Realms 007 said:


> Franciz said:
> 
> 
> 
> Dear All,
> 
> I am trying to use reverse electro plating cell for gold pin for the first time.
> I am using a 6V 7A battery charger, Lead cathod and copper mesh with 98% sulfuric acid in a 1L breaker.
> Now i have problem, The problem is the gold strip out from the pin in flake form(not in black powder form) and also copper is dissloving and stick on my lead cathod Acid Turn Green/Blue. The acid is not hot.
> 
> I did not saw any black powder but only tiny gold flake, Lead cathod full of copper. What actually did i go wrong?
> 
> I have also try out 6V and 12V battery charger but in difference current but the result is still the same.
> Please help me out....
> Thanks........
> 
> 
> 
> 
> I think if you will lower your voltage and current you will solve part of your problem.
Click to expand...


Hi barren, 
I have already lower down the current but it is still the same.
Thanks


----------



## qst42know

Battery acid is usually already diluted when they get it. You might go to the auto parts store or back to the battery store and see if they have cheap specific gravity battery tester.


----------



## Geo

brand new battery acid needs to be evaporated roughly two thirds of its volume to be concentrated. the battery acid i get is about 25%? maybe, ill have to check the box. battery acid is simply diluted sulfuric acid. if you were using the acid straight from the box, you were using diuted sulfuric.


----------



## Franciz

Geo said:


> brand new battery acid needs to be evaporated roughly two thirds of its volume to be concentrated. the battery acid i get is about 25%? maybe, ill have to check the box. battery acid is simply diluted sulfuric acid. if you were using the acid , you were using diuted sulfuric.



Hi Geo, 

Do you mean i need to boil the acid until it evaporated roughly two thirds of its volume?
The battery acid i get is in a normal beer bottle and is written 98% Sulfuric Acid on the bottle and it only cost me about USD50Cents for 450ml.
Maybe all sulfuric acid for new battery is diluted, If so what should i do for 98% sulfuric?

What is the recommend AMP for a 6v or 12v battery charger for reverse electroplating process.

Thanks Everyone for sharing......


----------



## Geo

when you are concentrating sulfuric acid you have to be very careful. WARNING : hot sulfuric acid will cause sever chemical burns and blindness on contact with eyes. i use an old pyrex coffee pot, it has been heated enough to temper it well. be sure it has no cracks or chips missing. set up a hot plate in an area outside a safe distance from, well, everything. place the acid in the pot and the pot on the hot plate. heat in stages (low) (medium) (high) give each stage time to heat up. when the acid begins to boil, water vapor will be released. monitor the process closely. as the volume reduces the boiling will slow down (more water = more vigorous boiling, less water = more gentle boiling). at this stage the vapor escaping is acid vapor (do not breath). when the boiling has all but stopped the acid will heat quickly and the container will fail so the final stage must be monitored very closely. when you observe very little boil but alot of vapor the acid is concentrated to the point where you are losing acid. unplug the power cord, that i forgot to mention using for the hot plate, and let the solution cool where it sits before trying to handle it because it is now at its most dangerous. after it cools you can use a plastic funnel and put it in a thick plastic container with a tight fitting lid. this acid will be suitable for the sulfuric stripping cell.


----------



## qst42know

Franciz 

I see you are in Thailand. I have no idea what concentration is available in your country so you need some other way to test the concentration.

Do you have an accurate scale and measuring cylinder, or a hygrometer?


----------



## Franciz

qst42know said:


> Franciz
> 
> I see you are in Thailand. I have no idea what concentration is available in your country so you need some other way to test the concentration.
> 
> Do you have an accurate scale and measuring cylinder, or a hygrometer?



How are you Qst42know, Hope you are fine.
I have no idea how to test it i am just trying new method for gold recovery.
All i have is 98% concentrate sulfuric acid, Should i boil it?

And also i have access to 98% Sodium hydroxide in flake form can i use this for my new reverse electroplating cell?
How should i start?

Thanks alot.......
Franciz


----------



## qst42know

> All i have is 98% concentrate sulfuric acid, Should i boil it?



Your sulfuric at 98% is as concentrated as it is going to get unless it has been exposed to moisture from the air.

For concentrating it only needs heated, boiling is the wrong idea. Boiling concentrated sulfuric emits a deadly white smoke and it's not necessary to heat to such a high degree to drive out the water.


----------



## Franciz

qst42know said:


> All i have is 98% concentrate sulfuric acid, Should i boil it?
> 
> 
> 
> 
> Your sulfuric at 98% is as concentrated as it is going to get unless it has been exposed to moisture from the air.
> 
> For concentrating it only needs heated, boiling is the wrong idea. Boiling concentrated sulfuric emits a deadly white smoke and it's not necessary to heat to such a high degree to drive out the water.
Click to expand...


Can you teach me what should i need to do with 98% Diluted sulfuric acid before i can use it for my Reverse Electroplating Cell?
And also can i use a 6V 10A battery charger for this?
Thanks alot as you are always begin so helpful..

Best Regs....


----------



## patnor1011

Concentrated sulfuric acid is one of the most dangerous substances used in refining. Do not attempt to proceed if you do not have proper lab equipment and safety gear and procedures. Just google pictures of accidents with hot sulfuric to see what it can do with skin or lungs. One drop of hot sulfuric and your eye is gone, one breath of white vapour and your lungs are burned. 

Invest to proper lab glass and vessels, start slow and small, be safe.


----------



## Franciz

patnor1011 said:


> Concentrated sulfuric acid is one of the most dangerous substances used in refining. Do not attempt to proceed if you do not have proper lab equipment and safety gear and procedures. Just google pictures of accidents with hot sulfuric to see what it can do with skin or lungs. One drop of hot sulfuric and your eye is gone, one breath of white vapour and your lungs are burned.
> 
> Invest to proper lab glass and vessels, start slow and small, be safe.



Yes, I am trying to start small. I have brought a 1L Pyrex breaker, goggle, glove, mask and a 6V adjustable AMP from 2amp to 20amp. First, After i saw Steves viedo i thought i could just simply start with 98% sulfuric acid that i brought from battery store and pour in in the breaker then black wire on lead anode and red wire on copper mesh But end up copper is dissolving and stick to the lead and also gold is not in black powder form, it strip out from the pin in tiny gold flake form and refuse to sink(End up a mess).

I am hoping to get someone who is keen to teach me step by step here and what should i do with my 98% diluted sulfuric for it to be able to use in my Sulfuric gold cell.
Thanks


----------



## qst42know

If the sulfuric is attacking copper it's not concentrated enough. Concentrating battery acid is covered in the forum handbook.

http://goldrefiningforum.com/phpBB3/download/file.php?id=518


----------



## Franciz

qst42know said:


> If the sulfuric is attacking copper it's not concentrated enough. Concentrating battery acid is covered in the forum handbook.
> 
> http://goldrefiningforum.com/phpBB3/download/file.php?id=518



Thanks Qst42know,

I have read it and will try it tomorrow(Page12). So one more question regarding the voltage and Amp for my battery charger please, May i know is 6V 10amp ok for a 1L breaker and normally how long does it takes to strip those pin(10Grams gold pin per batch)?

Thanks again.....


----------



## qst42know

Many here have used a 6 volt 10 amp battery charger with success. 

Making a basket that fits a 1 liter beaker is going to be a bit of a challenge. You want to try to keep 3 inches between the anode and cathode. And the edge of the basket should be as low as possible on the front edge to give a straight line between the pins and the lead strip.

You may not be able to fit 10 grams of pins in a basket that suits these requirements. 

Most pins in a well designed basket should strip in seconds.


----------



## butcher

Franciz,

Have you studied the many posts on the forum discussing this cell?
Have you visited Lazersteve's web site? (See his posts for link).
Have you read the General reaction list? (And have you seen catfish's document on concentrating 32% battery acid?
Have you read the dealing with waste?
Have you read the safety section?

Can you answer these questions with a yes, and then you should have no trouble running your cell.
If your answer is no, spending some time studying these will help you (answering your questions and give you a working knowledge of the process), and (save everyone time answering your questions, many of which you have no clue to ask about), it may also give you some more questions, of steps you have not got to yet).
Without studying first you can expect to make every mistake that is possible, then spend your time asking help to get out of all of these messes, believe me that is not a quick way to learn, reading and studying you will spend far less time learning and be up and running, instead of constantly working to clean up a mess.
You will also discover many other hidden secrets of recovery and refining when you look for your answer to this question by studying, you would miss that information by asking a member a question and getting one answer.

I wish to remind anyone using this cell or concentrated sulfuric acids that if they have to dilute the acid, always pour the acid into the water.

NEVER POUR WATER INTO CONCENTRATED SULFURIC ACID.

The water would steam violently and could splash this acid all over you, at minimum eating holes in your clothing, or worse blinding, or burning you horribly.
If you are new to this make a note in your mind and on your wall.

A whole world of knowledge is just setting there waiting for you to discover it, and use it to recover gold and valuable metals. you will just miss if you do not read it.


----------



## Franciz

qst42know said:


> Many here have used a 6 volt 10 amp battery charger with success.
> 
> Making a basket that fits a 1 liter beaker is going to be a bit of a challenge. You want to try to keep 3 inches between the anode and cathode. And the edge of the basket should be as low as possible on the front edge to give a straight line between the pins and the lead strip.
> 
> You may not be able to fit 10 grams of pins in a basket that suits these requirements.
> 
> Most pins in a well designed basket should strip in seconds.



I will try it again in this few day after concentrating sulfuric acid and i will update here for result if i do have any problem again please allow me to question again

Thank you Qst42Know, 
I really appreciate your help. It seems i got the most direct answer from you. 
May you success in everything you wish.


----------



## Franciz

Dear all, 

May i know how deep is the gold cell used in Steves website. It look great and i am looking to buy 1 on Ebay but it seems most of it got only 2inches deep.
Thanks....


----------



## lazersteve

The sulfuric cell in my video is about 3.5" deep. I sell them on my website (store link below) for $10 plus shipping and they come with a plastic lid. The manufacturer of the dish I use in the video changed to a wider design and slightly shallower (about 3" deep). On the shorter dish mount your anode outside the cell so it does not get in the electrolyte.

Steve


----------



## Franciz

lazersteve said:


> The sulfuric cell in my video is about 3.5" deep. I sell them on my website (store link below) for $10 plus shipping and they come with a plastic lid. The manufacturer of the dish I use in the video changed to a wider design and slightly shallower (about 3" deep). On the shorter dish mount your anode outside the cell so it does not get in the electrolyte.
> 
> Steve



Thanks Steve,

I will try concentrating the sulfuric tomorrow and try a few pin on a breaker to make sure i know how to do it.
If it does works then your dish will be the best for me for few hundreds grams per batch.
I am just afraid if i don't know how to do it then the dish is useless to me.
I am not going to give up for sure for learning new method of recovering GOLD!!!
By the way, you have made a great video and those equipment for sales are all in great price. 
Thanks for sharing...


----------



## Franciz

HELLO ALL,

I have already concentrated the sulfuric from battery acid, I boil it until left 1/3 of the volume. I have also try using lead and also a copper wire to hold a pin using 12v 15A current. Guess what??? I succeed to stripped the gold pin without the acid attacking the copper !!!LOL...SUCCEED!!! Thank you everyone for helping all the time... This is the best forum i ever met, All professional is here helping one and other.
I am contacting Steve to combine shipping for his Dish and his copper mesh for my little gold mine machine... :lol: 
After if i got the dish and copper mesh from Steve and if succeed please allow me to Post a step by step guide with Picture for anyone who know nothing about chemical or found it difficult to understand but willing to try until it succeed no matter what like me.

Personally i wish to thanks Qstknow and Steve for trying their best to make me understand more with their experiences, THANK YOU!!! 
I may still have a long long way to go to master it but this is already a good start for me. Please allow me to ask question if i had problem for gold recovery in future...

Thanks Everyone Here,

WARMEST REGARDS,
Francis


----------



## qst42know

Congratulations. 8)


----------



## Franciz

qst42know said:


> Congratulations. 8)



Thanks Qst, You are always so helpful...


----------



## Franciz

Dear All,
Help needed again, I have stripped about 1.5Kg of gold pin in 2litre of sulfuric cell. 
Now i have problem recovering the black powder, I pour the black liquid slowly to new container with 4litre of water. The problem is those black powder refuse to sink.

Should i add more water?

Franciz


----------



## qst42know

You can clean what did settle quickly and set the remaining dark solution aside. If it doesn't settle in a few days it should when you re-concentrate. You can use this over and over, you will get it eventually.

You can test a small amount of the dark solution with HCL for silver.


----------



## Geo

let everything sit for a day or more, until the liquid at the top is close to clear (you can see light through it). then syphon down to the powder. the liquid syphoned off needs to be in a container with a lid, tightly capped. the powder will have some acid in it. place this in a container that will hold the acid+powder and 3 more equal amounts of water. add the acid+powder SLOWLY to the water checking to see how hot it is getting (too much heat can cause glass to break). when all the acid+powder has been added stir and let powders settle (this may take another day) completely. when settled, decant this liquid to another container to reclaim your acid later. add water back to the powder to the level before and let settle. let this settle and decant to another container, neutralize this liquid and discard. repeat the last step until water remains clear. decant the last time and process powder.


----------



## Franciz

Dear Qstknow and Geo,

Thanks for your advice. I will wait and see if it settle down to the bottom tomorrow since it is only 3Hr since i dilute the cell.

Thank you...
Franciz


----------



## skullsbox01

I friend, i have one question on the process:

After having stripped the gold with the cell, can i recovery gold from sludge, filtering the soltuion and whashing the powder?

Thanks


----------



## Geo

skullsbox01 said:


> I friend, i have one question on the process:
> 
> After having stripped the gold with the cell, can i recovery gold from sludge, filtering the soltuion and whashing the powder?
> 
> Thanks



your gold will actually be the "sludge" precipitate in the cell. citing Hoke on this, the "sludge" should be referred to as "slimes" or "cell slimes". the gold can not stay in solution in the stripping cell environment. from what i understand (if im wrong, someone will correct me) persulfate is formed in the immediate vicinity of the anode dissolving the gold. the gold ions get carried with the current flowing to the cathode. as the gold ions leave the area where the persulfate is being formed, they precipitate out as metallic gold. this precipitate can be very fine and can float for days before settling.

i would like to edit this. im changing the "perchlorate" to "persulfate". sorry about that


----------



## niteliteone

Geo,
You got it right as far as I know.
Might also want to mention the gold that re-forms in the Sulfuric acid will be black and look like soot, but that is the gold.
Good catch on the missed name


----------



## hiscomm

I recently did some experimentation with reverse plating on a small gold plated baby spoon onto a stainless steel 5/8 round. I used a commercial gold stripper that is noncynanide. It seemed to strip the spoon quickly, I had my power 1.5- 2.5 volts but what showed up on my stainless was a black residue coating. I did not see a gold 24 K color which was on the spoon. Also my stainless is not a super high grade it that matters or not. Is that residue the gold?
Please set me straight! thanx!


----------



## goldsilverpro

The commercial stripper is proprietary and the ingredients are a mystery. It might help if you would post a copy of the operating instructions.


----------



## hiscomm

hiscomm said:


> I recently did some experimentation with reverse plating on a small gold plated baby spoon onto a stainless steel 5/8 round. I used a commercial gold stripper that is noncynanide. It seemed to strip the spoon quickly, I had my power 1.5- 2.5 volts but what showed up on my stainless was a black residue coating. I did not see a gold 24 K color which was on the spoon. Also my stainless is not a super high grade if that matters or not. Is that residue the gold?
> Please set me straight! thanx!




Temperature 120-150ºF (49E - 65E C)
Current Density Reverse plate at 3-6 Volts (30-100 ASF)
PH 4-4 2
Beaker Pyrex
Anodes Stainless Steel
Bath Set Up:
1. Fill beaker with Strip-Free™ and heat to 140EF.
2. Check connections from rectifier to anode and work to be sure they are
reversed. Negative (-) and positive (+) wires are connected properly.
The work should be charged positive (+) , and the anode negative (-).
Turn rectifier on.
3. Reverse Plate for 30-90 seconds at 3-6 volts depending on size of part
and thickness of gold which is being stripped.
4. Larger parts require slightly higher voltage, while smaller parts
require lower voltage. If part shows any burning such as dark grey or
rough deposits around the edges, you are burning the part and must
lower the voltage. If part is not stripped after 3- 5 minutes of
stripping, voltage it too low, there increase voltage slightly.
5. After stripping rinse part thoroughly in water and either dry or
replate. If replating: Dip part in Activator-T for 2 minutes, rinse, plate
a mirror finish, rinse, then continue plating process with a Decorative
finish such as gold or silver.
Trouble Shooting:
Pieces not Plating
Plated layer under gold is black or
grey
or
Pieces turn hazy, cloudy, and too
dull
$ Check power supply, make sure
switch is on.
$ If switch is on, check fuse.
$ Check connections from power
supply to anode and part.
$ Voltage too low
$ Anode/ Cathode connections are
reversed to plate not strip.
$ Voltage is too high.
$ Excessive stripping time


----------



## NobleMetalWorks

Geo said:


> brand new battery acid needs to be evaporated roughly two thirds of its volume to be concentrated. the battery acid i get is about 25%? maybe, ill have to check the box. battery acid is simply diluted sulfuric acid. if you were using the acid straight from the box, you were using diuted sulfuric.



Geo is right, battery acid is diluted sulfuric acid. Also, you are going to pay a lot more for it and at least in the State of California, you have to give personal information when you purchase it.

I would try to look for a different source for your sulfuric acid, and make sure it's 95% or better, preferably 98%.

The reason your sulfuric stripping cell doesn't work when you have lower concentrations of sulfuric acid is because it cannot produce persulphuric acid when the electricity is applied. Sulfuric acid doesn't dissolve gold, it's the creation of persulphuric acid at the cathode that dissolves/deplates the gold from the material, and as it changes back to sulfuric acid, then drops the gold out of solution as black sand. But in order to create persulphuric acid, you need to start with a concentrated solution of sulfuric acid.

Scott


----------



## Geo

NobleMetalWorks said:


> it's the creation of persulphuric acid at the cathode that dissolves/deplates the gold from the material



this should be anode, otherwise, nice explanation.


----------



## hiscomm

As per my last post, I reverse plated a gold 24K spoon on to a 5/8 stainless steel round. The spoon was stripped and the stainless area that was in solution had a black soot looking appearance built up on it. I assume that is gold. If so what is the best way to get it off the round?


----------



## Geo

the black "soot" is the gold. it should not be adhered to the stainless too tightly to just rinse off. you might use a a soft brush and gently brush it under water to remove the powder. im accustomed to the sulfuric stripping cell and have never used what you describe but from your description, im sure it didnt redeposit on the stainless steel tightly.


----------



## hiscomm

Geo said:


> the black "soot" is the gold. it should not be adhered to the stainless too tightly to just rinse off. you might use a a soft brush and gently brush it under water to remove the powder. im accustomed to the sulfuric stripping cell and have never used what you describe but from your description, im sure it didnt redeposit on the stainless steel tightly.




Thanx Geo, my theory was to transfer on to stainless, which I thought would replate in the form of gold plate and since I wasn't interested in an actual plate finish, but to just scrape off and when I got enough, melt it into a transferable form. I'm wondering if I can build onto what I have started on the stainless and when builds up more scrape it off, I have other pieces that can be stripped?


----------



## etoxiran

I have question about reverse electroplating:

- how about popular stainless steel (grade 316, or other available in mesh form) as material for anode?

I have already 1dm3 of 98% Analytic grade H2SO4 on shelf, and a lot of 300 or 400 stainless mesh (and other sizes). I don't want to contaminate my acid with other metals. From pdf on links it's look like that any kind of stainless steel should be apropriate for this job. Its look like even it wold be superior than copper mesh. 

Anyone try it? If i don't find answer I will try it, because I have too much plated items to fully dissolving in HNO3, some of them are partially stripped, some of them not. Cyanade leaching looks interesting, but without proper safety setup, I'm not looking this way.

Of course I will submit photos later 

References:

http://www.parrinst.com/wp-content/...1/07/Parr_Stainless-Steels-Corrosion-Info.pdf

http://stainless-steel-world.net/pdf/sswsup1005_duplex_rolledalloys.pdf


----------



## justinhcase

I some time's use an Ammonium and sodium Chloride electrolyte in my stripping cell. U.S. Patent 4895626
It works very much like sulphuric acid but is much easier to handle have never used it with pins only to take off gold plating from flat ware and bangles.


----------



## bmgold2

justinhcase said:


> I some time's use an Ammonium and sodium Chloride electrolyte in my stripping cell. U.S. Patent 4895626
> It works very much like sulphuric acid but is much easier to handle have never used it with pins only to take off gold plating from flat ware and bangles.



Here's that patent http://www.google.com/patents/US4895626


----------



## Geo

Here's what the patent states: "This invention relates to the refining and purification of karat gold to 98% purity." Even though it may dissolve the impurities in karat gold leaving the mostly pure gold, I dont see this working for electronic scrap. For one thing, it dissolves the impurities while leaving the pure gold undissolved in the anode bag. Stripping is the opposite of that where the gold is dissolved and base metal stays intact. As for the second thing, it doesn't self precipitate the base metal as a true stripping cell self precipitates the gold. The base metals stay locked in the ammonia solution. Pins yielding as little as 0.01% or even as high as 0.1% would be impossible to process this way due to chemical cost. Header pins may yield 2g per pound. How much solution would you need to process 15-16 pounds of pins?


----------



## justinhcase

I have not used the Ammonium chloride for pins but if you hang a plated item like a large bangle in it it parts the plate very nicely.
I have tried it with 375 gold but I found the process messy and i could not be sure that I had not lost any fine gold.
Thick Plate comes off in nice flakes and I take the pice out as soon as it has been cleaned, so i though I would suggest it as the chloride's are pennies and are reasonably safe unlike sulphuric acid which is pounds and very hazardous
I like your method of letting pins rust which is what I will try my self next time.


----------



## g_axelsson

Anyone that reads patents should bear in mind that there is no requirement that the process should work. This patent is from our well known Peter Shor.

There is at least one wrong statements in that patent and it just shows how much of an expert Peter is.


Peter Shor about the electrolytic gold cell used in mints said:


> The gold deposited is "mint" grade, 98.5% purity.



And as an example he talks about refining 14k gold...


> The powdered gold was washed from the anode bag and assayed. It was found to be 98.7 to 99.3% gold. The impurities in this refined gold were 0.3 to 1.0% silver, 0.1 to 0.2% silicon and copper and less than 0.005% each of platinum, boron, palladium, manganese, tin, nickel, bismuth and chromium. Thus the recovered gold was considered purer than "mint grade" and suitable for re-use in the jewelry trade.


I don't think anyone on this forum would consider 99% good enough to sell to manufacturers and if they did they would probably lose a customer.

The patent is only referenced in two other parents, both from Shor. If this was working good then we would have seen the patent referenced from later patents and the process implemented in working methods. At best this is a recovery method and not a refining method.

Göran


----------



## necromancer

try this post if you have not seen it already

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=86&t=19971


----------



## leeloo

Is it possible to filter sulfuric acid after R.E.P., without rising, to reuse the acid? And rising remainder into same filter yet different container and at that point let the slime and gold dry completely eventually placing sediment into AR for further dissolution?


----------



## g_axelsson

leeloo said:


> Is it possible to filter sulfuric acid after R.E.P., without rising, to reuse the acid? And rising remainder into same filter yet different container and at that point let the slime and gold dry completely eventually placing sediment into AR for further dissolution?


Welcome to the forum, leeloo. This is a good thread to read
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=17025

And you should take your time to read all the introduction threads and how to search the forum too. Everything is here for you to read. 8) 

Göran


----------



## solar_plasma

Since chlorine would evolve at the anode, why wouldn't it just dissolve the gold? I am sure it will. If this is working at all, all dissolved gold would cement at basemetals or get reduced by reducing chlorides. Though a strong oxidizer like Clnasc would leave all chlorides in there highest oxidation stage. Not that I expect any advantages from Shor's cell, I dislike the idea of adding ammonium to my recovery processes, but just for the curiosity.


----------

