Silver Plated Scrap Processing

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yoyo282

Member
Joined
Jan 25, 2023
Messages
8
Location
India
Hello,

I have approximately 300 kg silver plated scrap (3% silver on copper) from which I am planning on extracting silver. I have read several protocols and the H2SO4 /HNO3 (3 parts H2SO4 and 1 Part 68% HNO3) seems to help me strip the silver from the scrap really well. However, when I dilute the mixture immediately and add HCl or regular noniodized salt, I am not able to get any AgClprecipitate. Can someone please help me with this? What is the actual protocol? Is there an original thread on this where this is discussed in detail? Am I doing this correctly?

Looking forward to getting some suggestions from this awesome community.

Thanks
 
Hello,

I have approximately 300 kg silver plated scrap (3% silver on copper) from which I am planning on extracting silver. I have read several protocols and the H2SO4 /HNO3 (3 parts H2SO4 and 1 Part 68% HNO3) seems to help me strip the silver from the scrap really well. However, when I dilute the mixture immediately and add HCl or regular noniodized salt, I am not able to get any AgClprecipitate. Can someone please help me with this? What is the actual protocol? Is there an original thread on this where this is discussed in detail? Am I doing this correctly?

Looking forward to getting some suggestions from this awesome community.

Thanks
First of all, I think the general consensus is that Plated Silver are very hard to do in an economical viable way.
The only option seem to be the water cell, which has been discussed in length.

Regarding your issue, I will start by asking if you are sure it is Silver in there?
Silver Chloride should form immediately, that is why I'm asking.
 
First of all, I think the general consensus is that Plated Silver are very hard to do in an economical viable way.
The only option seem to be the water cell, which has been discussed in length.

Regarding your issue, I will start by asking if you are sure it is Silver in there?
Silver Chloride should form immediately, that is why I'm asking.
I am positive that there is silver in there! In the place I live, the reagents are pretty cheap, and is probably worth refining it.
 
First of all, I think the general consensus is that Plated Silver are very hard to do in an economical viable way.
The only option seem to be the water cell, which has been discussed in length.

Regarding your issue, I will start by asking if you are sure it is Silver in there?
Silver Chloride should form immediately, that is why I'm asking.
According to this description, the plating can be attacked by HCl too. was this checked?
 
Hello,

I have approximately 300 kg silver plated scrap (3% silver on copper) from which I am planning on extracting silver. I have read several protocols and the H2SO4 /HNO3 (3 parts H2SO4 and 1 Part 68% HNO3) seems to help me strip the silver from the scrap really well. However, when I dilute the mixture immediately and add HCl or regular noniodized salt, I am not able to get any AgClprecipitate. Can someone please help me with this? What is the actual protocol? Is there an original thread on this where this is discussed in detail? Am I doing this correctly?

Looking forward to getting some suggestions from this awesome community.

Thanks
Hi, If i calculate correct , you wish to recover 9Kg of silver from 300Kg of plated material. Using "cheap reagents" may create a magnitude of waste, which has to be dealt with professionally.
IMHO a reverse electroplating cell may help you with your quest if there is really silver on your material.
After recovery, you can choose which method you will use to refine your silver.

In any case download Hoke`s book and study it then visit the safety section then check out the dealing with waste section of the forum.

Pete
 
According to this description, the plating can be attacked by HCl too. was this checked?
I have tried boiling the silver plating directly in HCl and the plating comes off after a point of time. The solution turns black and on addition of water leads to precipitation. This process releases a lot of chlorine gas and takes quite a bit of time to dissolve. Is there a better way to do this without boiling the HCl?
 
I have tried boiling the silver plating directly in HCl and the plating comes off after a point of time. The solution turns black and on addition of water leads to precipitation. This process releases a lot of chlorine gas and takes quite a bit of time to dissolve. Is there a better way to do this without boiling the HCl?
"addition of water leads to precipitation". This is not the way silver reacts. I assume another metal is in the majority (zinc? tin?)
 
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Your method was used by manufacturers of silver plated items. But as I recall, the acid ratios were different. I believe it was more like 95% sulfuric with just 5% nitric. I don't know if that's causing your problem.

The mixture was also used hot, which also increases the hazards.

Still, if you're actually stripping any of the silver, I would expect some precipitate.

How many pieces are you stripping before trying the precipitation? Are you getting complete stripping down to the copper?

We had a member who was familiar with the method named goldsilverpro who wrote a bit about it. You can try a search with him as the author.

Dave
 
Your method was used by manufacturers of silver plated items. But as I recall, the acid ratios were different. I believe it was more like 95% sulfuric with just 5% nitric. I don't know if that's causing your problem.

The mixture was also used hot, which also increases the hazards.

Still, if you're actually stripping any of the silver, I would expect some precipitate.

How many pieces are you stripping before trying the precipitation? Are you getting complete stripping down to the copper?

We had a member who was familiar with the method named goldsilverpro who wrote a bit about it. You can try a search with him as the author.

Dave
I was basically trying 5-10 pieces of silver stripping in H2SO4- HNO3 solution before trying the precipitation. Do you think I should try industrial-grade NaCl instead of kitchen salt to see if this helps with the precipitation?
 
Melt it and recover the copper by electrolysis. Collect the slimes and recover the silver. You find a lot of threads on the subjects here.
That is an interesting idea. Do you know exactly which thread I should read to setup a copper recovery/deposition cell? Would love to give this a try.
 
"addition of water leads to precipitation". This is not the way silver reacts. I assume another metal is in the majority (zinc? tin?)
How should I work with HCl to remove the silver stripping? Has anyone tried HCl in conjunction with H2O2 to strip the silver? There seems to be a thread on this as well but couldn't find the actual protocol.
 
How should I work with HCl to remove the silver stripping? Has anyone tried HCl in conjunction with H2O2 to strip the silver? There seems to be a thread on this as well but couldn't find the actual protocol.
HCl + H2O2 will turn silver to white silver chloride. But - no evidence for silver was shown yet. I wonder if not the 3% refers to the plating film only
 
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yoyo282
You have received the best suggestions on the easiest way(s) to solve your ”situation”(provided there is silver in the material) from some of the most professional members here already.
Did you even read what was in the link @Yggdrasil was kind enough to bring out for you?
Just wondering as you keep going on your own 'track'.
This forum has a search function which is exceptionally good. Try it, you know 😉
Sincerely
/Dennis
 
I was basically trying 5-10 pieces of silver stripping in H2SO4- HNO3 solution before trying the precipitation. Do you think I should try industrial-grade NaCl instead of kitchen salt to see if this helps with the precipitation?
Silver chloride is very insoluble, even in acidic conditions. Only common thing that dissolve AgCl is ammonia. So we need to come back to the very beginning. How does you know it is silver plating, and not dip tin/zinc ? Which tests did you performed ?

There is plethora of metals other than silver, which are plated/dip coated on copper. Namely tin, zinc and nickel. And even more exotic ones. Possibility of having silver plating is real, but just colour of the surface isn´t sufficient proof you have thick silver plating.

To find if there is any Ag, dissolve some few grams of plated stuff completely in nitric acid. If the base metal is copper, you will obtain nice clear blue solution. If the coating is tin, not silver, it will create white/greyish cloudiness in blue solution = metastannic acid. It is very clear and visible sign you have tin in the material.

If there is any silver to be found, it will IMMEDIATELY precipitate upon addition of any soluble chlorides. Take regular salt in water, it does not matter if it is tech grade or food grade NaCl, it will work with any chloride, even KCl, CaCl2 or any other chloride you can imagine. AgCl will precipitate UPON CONTACT with salt solution IMMEDIATELY. If there is little concentration, you will see white cloud, if there is higher concentration, you will see formation of quark-like precipitate, heavy, coagulated and nicely sinking to the bottom, after a good stir.

If this won´t happen, unfortunately, you do not have silver in it. It is very sensitive and even minor silver will create big white cloud. Sensitive, I mean you can very reliably detect below 0,5g/L and even more dilute solutions.
 
I’m no expert, but I’ve tried this method for stripping silver off of plated silverware.

For some reason I found that it starts well, but as more and more material goes through the solution, the stripping doesn’t actually happen at all. For some reason I’ve been experiencing copper plating onto the silver plating!

So it gives a false impression that the silver was removed. Because there is a thin layer copper all over the item, but when I look more carefully and sand down a bit of the surface, the silver is still very much in tact…underneath the copper! I’m not sure why this is happening, because I’ve seen many videos of guys using the 3:1 conc. sulfuric and nitric acid mix, with good success.

But this may be why you’re not getting precipitation of Silver…because most of it is still on the items you processed, underneath the deceptive layer of copper?

Just a thought for you though I might be wrong, but try sanding some of the processed items with fine sand paper, and see if it reveals silver underneath the copper?
 
The most economical use of silver plated copper is as an additive to shredded circuit board. You'll get paid on both the silver and the copper. The caveat here is that you have to get paid on a melt assay, not a sampling of shredded material. The other is that you want to keep it diluted enough that you aren't picking up excess processing fees from the introduction of too much nickel in the melt.
 
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