Fully dissolving plated pins or just enough to remove foils.

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IntelligentEye

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Hey everyone, I’m hoping someone with more experience on the matter can give me some pointers. When refining gold plated pins, do you completely dissolve the base metals or just enough for all the foils to become detached. Secondly, if not fully dissolving the pins, how do you completely separate the foils that are intermingled with the now stripped pins? Thanks for your input!
 
Hey everyone, I’m hoping someone with more experience on the matter can give me some pointers. When refining gold plated pins, do you completely dissolve the base metals or just enough for all the foils to become detached. Secondly, if not fully dissolving the pins, how do you completely separate the foils that are intermingled with the now stripped pins? Thanks for your input!
This is depends on the pins, you and so on.
If you are sure the foils are completely detached and can separate, go for it.
But most of the time it is not possible to ensure it.
So then you choose either prolonged base metal treatment or direct dissolving th Gold.
In the latest case make sure all metals are dissolved.
 
This might sound counter intuitive but with recovery you need to accept that in some cases you will not recover all the values unless you have unlimited free time or want to produce voluminous quantities of toxic waste solutions.
If you watch any of the gold mining programs they have to accept that they will lose some of the material in their sluices if they are working for wages and not for the program.
 
Secondly, if not fully dissolving the pins, how do you completely separate the foils that are intermingled with the now stripped pins?

You kind of answered your own question didn't you

You have two options

1) dissolve all the base metal to get full recovery of the gold foils = more chem = more base metal waste - or ----------

2) use less chem to just "loosen" the foils - BUT - suffer "some" gold lost to foils tied up in the undissolved pin some of which will likely not be fully detached from the pins as well as "some" that just want to stay trapped in the pins - even though they are fully loosened

Kurt
 
Hey everyone, I’m hoping someone with more experience on the matter can give me some pointers. When refining gold plated pins, do you completely dissolve the base metals or just enough for all the foils to become detached. Secondly, if not fully dissolving the pins, how do you completely separate the foils that are intermingled with the now stripped pins? Thanks for your input!
I dissolve all base metals first. I also process pins in plastic which leaves separating the foils. A plastic kitchen strainer with slots big enough for foils to pass through, not pins, will work. Use a spray bottle with water.

Janie
 
I stop trying dissolving pins unless they are really thin. Even then AP may be cheapest process even though it literally take ages.

There are better ways to extract gold from pins without creating buckets of waste solutions which you will need to deal with eventually.
 
Hey everyone, I’m hoping someone with more experience on the matter can give me some pointers. When refining gold plated pins, do you completely dissolve the base metals or just enough for all the foils to become detached. Secondly, if not fully dissolving the pins, how do you completely separate the foils that are intermingled with the now stripped pins? Thanks for your input!
Gold recovery from plated pins (magnetic mostly) is more effective with a sulfuric stripping cell than other methods. Less waste, high recovery rate if done properly, reusable acid with minimal loss (since acid from washwater can be reclaimed as well).

Creating low quantity of waste is the biggest challenge.

Search the forum for sulfuric stripping cell.

Pete
 
Read Hydrometallurgy publication of 1980 on sulfuric acid thiourea gold research. Not expensive fast vary little waste if any. But dont expect to buy a new truck from the gold on the pins.
 
For nonmagnetic pins, I always totally dissolve the pins. But, as time is not an issue for me, I can wait while the AP does its thing. I do it VERY slowly over WEEKS, allowing the solution to warm and cool over and over in my plastic greenhouse, until the reactants are utterly depleted, so my liquid waste is the absolute minimum the process can possibly use.

I then reduce all the copper out with the shorted-galvanic cell method I describe in another post, and after that I let the resulting solution dry to concentrated iron salt brine (with some tin, nickel, and whatever else the pins' cores were composed of).

With this process, all my waste thus far fits into a single 5-gallon container.

Now, if you use sulfuric stripping for all the pins, you can decompose much of the resulting sulfate metal salts in a fairly simple process, especially if you convert most of it into iron sulfate, which has the additional benefit of being pretty much nontoxic.
 
For nonmagnetic pins, I always totally dissolve the pins. But, as time is not an issue for me, I can wait while the AP does its thing. I do it VERY slowly over WEEKS, allowing the solution to warm and cool over and over in my plastic greenhouse, until the reactants are utterly depleted, so my liquid waste is the absolute minimum the process can possibly use.

I then reduce all the copper out with the shorted-galvanic cell method I describe in another post, and after that I let the resulting solution dry to concentrated iron salt brine (with some tin, nickel, and whatever else the pins' cores were composed of).

With this process, all my waste thus far fits into a single 5-gallon container.

Now, if you use sulfuric stripping for all the pins, you can decompose much of the resulting sulfate metal salts in a fairly simple process, especially if you convert most of it into iron sulfate, which has the additional benefit of being pretty much nontoxic.
The Sulfuric stripping cell do not produce much waste at all if operated correctly, since it do not dissolve base metals.
And if you leave the collected Gold to drip off properly in a glass fiber filter practically all the acid can be reused.
 
The Sulfuric stripping cell do not produce much waste at all if operated correctly, since it do not dissolve base metals.
And if you leave the collected Gold to drip off properly in a glass fiber filter practically all the acid can be reused.
I can understand it would work that way for gold-plated kovar or steel, since conc sulfuric will not react with them, but what about brass or copper-core pins? Sulfuric reacts with those metals.
 
I can understand it would work that way for gold-plated kovar or steel, since conc sulfuric will not react with them, but what about brass or copper-core pins? Sulfuric reacts with those metals.
Concentrated Sulfuric at 95%+ will not.
That is why it is important to not let the acid be subjected to air too long.
 
Guys, the brass and SS pins substreate if you dissolve it, it will leave you with metals in solution that are water pollutants if over 0.5 ppm. Zn, Cr, Ni in acidic solution ...and going to electroplating will not work, only waste more $ and is slow process. If you want to play that's a different story, but if you want to make a bit of money thee rule is simple: if a gram of gold is $ 60 and it cost you $60.5 to get it, go and buy pure gold and keep it until is valued at 70+ and sale it.
Simple and effective options are few:
1. Write and balance the reactions of copper, zinc and iron with sodium nitrate assuming the reaction takes place. Calculate how much sodium nitrate you need to use for whatever pounds of pins you have. Add 20+% more to conpensate for the contained water. Take a crucible like porcelan and mix the pins with the powder, cover with some more and put a lead on it. Heat at 350 C (670F) and let it work over night, or up to 24 hours if you have a lot of pins or less if you can heat at 600-700 C. Next day let it cool to under 220 F and dump in water. You'll get the base metals in neutral solution and you'll have "husks" of the gold pins. Rinse and and causting to water to precipitate metal hydroxide and use as fungicide in the garden. What you do with the gold if your fault if you wife finds out.
2. This is a bit of woodo description that follows, but if you want to be scientific you need and ORP to keep the solution potential in check. Prepare a solution of 12-15% sulfuric acid, like drain cleanner, add hydrogen peroxide and for each gram of expected gold add 1.5 g of thiourea, like hair removal (😂). Heat to 77F, pour over pins and stir nicely. You will get the gold off in something like 30-60 seconds and not touch the metal underneath. Very impressive when happens. If you want to undedtand how it works get a copy of 1980 Hydrometallurgy magazin and read it or google for patents and article on the formulation
 
Guys, the brass and SS pins substreate if you dissolve it, it will leave you with metals in solution that are water pollutants if over 0.5 ppm. Zn, Cr, Ni in acidic solution ...and going to electroplating will not work, only waste more $ and is slow process. If you want to play that's a different story, but if you want to make a bit of money thee rule is simple: if a gram of gold is $ 60 and it cost you $60.5 to get it, go and buy pure gold and keep it until is valued at 70+ and sale it.
Simple and effective options are few:
1. Write and balance the reactions of copper, zinc and iron with sodium nitrate assuming the reaction takes place. Calculate how much sodium nitrate you need to use for whatever pounds of pins you have. Add 20+% more to conpensate for the contained water. Take a crucible like porcelan and mix the pins with the powder, cover with some more and put a lead on it. Heat at 350 C (670F) and let it work over night, or up to 24 hours if you have a lot of pins or less if you can heat at 600-700 C. Next day let it cool to under 220 F and dump in water. You'll get the base metals in neutral solution and you'll have "husks" of the gold pins. Rinse and and causting to water to precipitate metal hydroxide and use as fungicide in the garden. What you do with the gold if your fault if you wife finds out.
2. This is a bit of woodo description that follows, but if you want to be scientific you need and ORP to keep the solution potential in check. Prepare a solution of 12-15% sulfuric acid, like drain cleanner, add hydrogen peroxide and for each gram of expected gold add 1.5 g of thiourea, like hair removal (😂). Heat to 77F, pour over pins and stir nicely. You will get the gold off in something like 30-60 seconds and not touch the metal underneath. Very impressive when happens. If you want to undedtand how it works get a copy of 1980 Hydrometallurgy magazin and read it or google for patents and article on the formulation
Bruh with this process I would be afraid of making witchbrew 2.0 😂
 
Guys, the brass and SS pins substreate if you dissolve it, it will leave you with metals in solution that are water pollutants if over 0.5 ppm. Zn, Cr, Ni in acidic solution ...and going to electroplating will not work, only waste more $ and is slow process. If you want to play that's a different story, but if you want to make a bit of money thee rule is simple: if a gram of gold is $ 60 and it cost you $60.5 to get it, go and buy pure gold and keep it until is valued at 70+ and sale it.
Simple and effective options are few:
1. Write and balance the reactions of copper, zinc and iron with sodium nitrate assuming the reaction takes place. Calculate how much sodium nitrate you need to use for whatever pounds of pins you have. Add 20+% more to conpensate for the contained water. Take a crucible like porcelan and mix the pins with the powder, cover with some more and put a lead on it. Heat at 350 C (670F) and let it work over night, or up to 24 hours if you have a lot of pins or less if you can heat at 600-700 C. Next day let it cool to under 220 F and dump in water. You'll get the base metals in neutral solution and you'll have "husks" of the gold pins. Rinse and and causting to water to precipitate metal hydroxide and use as fungicide in the garden. What you do with the gold if your fault if you wife finds out.
2. This is a bit of woodo description that follows, but if you want to be scientific you need and ORP to keep the solution potential in check. Prepare a solution of 12-15% sulfuric acid, like drain cleanner, add hydrogen peroxide and for each gram of expected gold add 1.5 g of thiourea, like hair removal (😂). Heat to 77F, pour over pins and stir nicely. You will get the gold off in something like 30-60 seconds and not touch the metal underneath. Very impressive when happens. If you want to undedtand how it works get a copy of 1980 Hydrometallurgy magazin and read it or google for patents and article on the formulation
Interesting, have you checked our waste treatment thread?
https://goldrefiningforum.com/threads/dealing-with-waste.10539/

Another ironic twist is that after telling us how dangerous our waste is, you recommend a chemical
that may or may not be a powerful carcinogenic substance.

Breathe slowly mate ;)

Edit to add link.
 
I am not sure if this answer Ted or Yaggdrasil....but to keep things straight.
I did not recommend anything. I pointed out a different approach to that particular processing to avoid goo and indicated the source of info. For whever is jolly it should know that world wide annually more people die from H2O poissoning that cyanide which means ignorance kills people more than anything and that his beloved one as well as the hard core Orthodox Jews use that mentioned chemical (thiourea) to remove the growing mustache and body hair to your fancy and after reading the info will find out that the process waste once neutralizer is a bening fertilizer.
Someone is going personal. It works for a smelter?
Interesting, have you checked our waste treatment thread?
https://goldrefiningforum.com/threads/dealing-with-waste.10539/

Another ironic twist is that after telling us how dangerous our waste is, you recommend a chemical
that may or may not be a powerful carcinogenic substance.

Breathe slowly mate ;)

Edit to add link.
Ted
 
😂 i guess if lowes home depot and the cosmetic sections of Walmart sale them for public it doesn't mean you can drink them or expose your skin to it too long before evolution respond to pressure and turns you into a bold monkey or "hairy Man" of Australia. You never know what you get playing.. .
 
I am not sure if this answer Ted or Yaggdrasil....but to keep things straight.
I did not recommend anything. I pointed out a different approach to that particular processing to avoid goo and indicated the source of info. For whever is jolly it should know that world wide annually more people die from H2O poissoning that cyanide which means ignorance kills people more than anything and that his beloved one as well as the hard core Orthodox Jews use that mentioned chemical (thiourea) to remove the growing mustache and body hair to your fancy and after reading the info will find out that the process waste once neutralizer is a bening fertilizer.
Someone is going personal. It works for a smelter?

Ted
Did you read the waste disposal thread?
 
Hey everyone, I’m hoping someone with more experience on the matter can give me some pointers. When refining gold plated pins, do you completely dissolve the base metals or just enough for all the foils to become detached. Secondly, if not fully dissolving the pins, how do you completely separate the foils that are intermingled with the now stripped pins? Thanks

Some pins have a undercoating of some kind of plating wich dissolves first and loosens the foils easily, and for some pins the gold will stick to it to the end..

If you dont want to start a sulfuric cell i would start by dissolving the pins and go from there. If 90% of the foils come off settle with that. You dont want another litre of acid cost/waste to chase the last 10%.

Just do a test with a few pins and you will see what method suits you the best. Try to keep acid waste at a minimum. If you process frequently run a sulfuric cell.
 
Concentrated Sulfuric at 95%+ will not.
That is why it is important to not let the acid be subjected to air too long.
Ah, I've never used sulfuric at a concentration that high before. It's rather hard to get in NJ. The purest I can get is from Rooto, and that has the organic inhibitors in it, so you have to add a little water and heat to make it do much of anything to metal.

I will finally be able to get a gallon of concentrated, so it's good to know this additional detail. So I could use a steel mesh strainer to separate the base metal bits from the gold particles. Hmmm, how does one go about separating the larger pieces of gold foil with this method?
 

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