Palladium plated onto gold legs from ceramic CPU's ?

[NobleMetalsRecovery]

I processed a lot of older ceramic CPU's, 486, Pentium Pro, etc.

The picture below is the legs that came off of the CPU's by soaking in nitric acid. Later I added some HCL. A lot of silver chloride was formed. When I filtered out the gold legs from the CPU's they were all plated with what I think may be palladium. It's a silver like color, but not as shiny as silver. The legs still stick to a manet.

I'm thinking of doing a dilute nitric soak to remove what I think is palladium Would like to hear some opinions as to what I'm dealing with hear.

 

[NobleMetalsRecovery]

Put some nitric on the pins and the gold color returned. Stannous test seems to indicate palladium.

 

[Martijn]

If the stannous test indicates a possible Pd, then DMG is the prescribed next step, i think.

 

[J.Najam]

Hello,

So I've a new case now. I don't know how these cases are getting to me but I see these as a useful learning curve through someone else's experiences.

This guy from India contacted me that he's trying to precipitate PD out of this solution. Material are pins as shown, although I doubted that it would contain Pd but his results show some sort of positive or false positive I'm not too sure as I'm not experienced with PGM salts. The pins were given a direct nitric bath to recover the foils and no HCl pretreatment was given. There are two tests that were carried out, tests on tissue paper and spot plate are stannous results whereas the small beaker with a foam in the center on top is the Dmg (which he told me after making the mess). What we see is a 1 litre test solution form nearly 10-12 more left to treat

Now the issue : suggested him if DMG is available to you, use it for precipitation. Otherwise IF the solution is PURE then only use copper for cementation. This lad, directly added a copper wire to the solution and reported that a black dust was forming onto the wire. But only a few hours later he reported that he can now see blue crystals and a white precipitate forming. As far as I understood the blue crystals may have been copper nitrate crystals due to too much copper saturation of the solution hence asked him to dilute it down a little and give it gentle heat. Henceforth he reported that they had indeed vanished. We can still see in his photos the grey precipitate on the bottom. Its not silver because I asked him to draw a sample of solution from his main bucket and add some HCl to it and see if he'd see any white cloudiness and the result was negative.

So the questions now :
1, Is this a false positive or a regular positive for PD?

2, what could be this grey matter and what can be done from here on out to recover if he has PD in this?

3, What would have been the best way to treat this given the material (any possible traces of tin\lead after using an air chisel)?

Thanks for your time one this one

 

[Yggdrasil]

Hello,

So I've a new case now. I don't know how these cases are getting to me but I see these as a useful learning curve through someone else's experiences.

This guy from India contacted me that he's trying to precipitate PD out of this solution. Material are pins as shown, although I doubted that it would contain Pd but his results show some sort of positive or false positive I'm not too sure as I'm not experienced with PGM salts. The pins were given a direct nitric bath to recover the foils and no HCl pretreatment was given. There are two tests that were carried out, tests on tissue paper and spot plate are stannous results whereas the small beaker with a foam in the center on top is the Dmg (which he told me after making the mess). What we see is a 1 litre test solution form nearly 10-12 more left to treat

Now the issue : suggested him if DMG is available to you, use it for precipitation. Otherwise IF the solution is PURE then only use copper for cementation. This lad, directly added a copper wire to the solution and reported that a black dust was forming onto the wire. But only a few hours later he reported that he can now see blue crystals and a white precipitate forming. As far as I understood the blue crystals may have been copper nitrate crystals due to too much copper saturation of the solution hence asked him to dilute it down a little and give it gentle heat. Henceforth he reported that they had indeed vanished. We can still see in his photos the grey precipitate on the bottom. Its not silver because I asked him to draw a sample of solution from his main bucket and add some HCl to it and see if he'd see any white cloudiness and the result was negative.

So the questions now :
1, Is this a false positive or a regular positive for PD?

2, what could be this grey matter and what can be done from here on out to recover if he has PD in this?

3, What would have been the best way to treat this given the material (any possible traces of tin\lead after using an air chisel)?

Thanks for your time one this one

First, tell him to get on some gloves or he will need a different kind of help!
The grey sludge will be metastannic acid, my guess at least.
I see no reason to have Pd in there.
Do he have his tests?
Did he drop the Gold first?

 

[J.Najam]

First, tell him to get on some gloves or he will need a different kind of help!

For sure!

The grey sludge will be metastannic acid, my guess at least.

If there is any, it is now mixed with Pd there. The copper did have back dust cemented

Do he have his tests?

Pics as shared above labeled : PD fb 1 and PD fb 2 are stannous tests. And images labeled PD dmg fb 6 and PD dmg fb 7 are dmg results.

Did he drop the Gold first?

This is an only nitrate solution, not AR.

 

[kurtak]

I doubted that it would contain Pd but his results show some sort of positive or false positive

The stannous test is most certainly a "false" positive (a light lime green) --- a true positive for Pd should be a "dark" forest green to even a near black green

whereas the small beaker with a foam in the center on top is the Dmg

The DMG test is also NOT a positive for Pd --- DMG - if Pd is present will precipitate a very distinct "canary yellow" precipitate - you can not mistake it (or yellow/orange if nickel is also in solution) - see attached pics

Kurt

 

[anarxi]

gray matter may be tin.
The contacts themselves are made of bronze.
The palladium underlayer is often found on connectors manufactured in the 1980s. the same as silver can be.
Since it cements the solution with copper.
although the color of the solution is very similar to the presence of palladium

 

[anachronism]

I agree with Kurt on this. The Pd colour is incredibly vibrant.

 

[J.Najam]

The stannous test is most certainly a "false" positive (a light lime green) --- a true positive for Pd should be a "dark" forest green to even a near black green


The DMG test is also NOT a positive for Pd --- DMG - if Pd is present will precipitate a very distinct "canary yellow" precipitate - you can not mistake it (or yellow/orange if nickel is also in solution) - see attached pics

Kurt

Thanks for the response and clarification.

If im not wrong, the image on the left is with nickel and the image on the right is pure Pd?

Also, if there isn't any Pd is solution, what then can be deduced about the black dust cementing onto copper with no silver (tested already) in solution?

 

[J.Najam]

gray matter may be tin.

Right, so we do have metastannic as Ygg has also pointed out

 

[Alondro]

For my Pd tests, I use a tiny white glazed ceramic cup and drop stannous solution into the unknown metal solution. If it's actually Pd, the instant the drop hit the unknown metal solution, it turns DARK black-green, which shows up very starkly against the gleaming white ceramic.

Light green is indicative of NICKEL, which makes sense from these legs since nickel is a) magnetic and b) often used as an under-plating for gold-plated electronics.

 

[J.Najam]

drop stannous solution into the unknown metal solution.

I beg your pardon. What do you mean by this please?

 

[kurtak]

lso, if there isn't any Pd is solution, what then can be deduced about the black dust cementing onto copper with no silver (tested already) in solution?

That is actually the result of the copper "starting" to oxidize when you put the copper in the solution - not necessarily the result of something cementing out

Kurt

 

[kurtak]

If im not wrong, the image on the left is with nickel and the image on the right is pure Pd?

yes that is correct - the bowl at the bottom with the black powder in it is actual Pd after reducing the Pd/DMG to Pd

Kurt

 

[Alondro]

I beg your pardon. What do you mean by this please?

The solution with the dissolved metal that you are trying to identify.

For my test, I put a few drops of the metal solution into the white cup, then drop in the stannous. If palladium is present, it makes a very obvious black cloud at once.

 

[J.Najam]

That is actually the result of the copper "starting" to oxidize when you put the copper in the solution - not necessarily the result of something cementing out

Kurt

Aah, well this can be deceiving if no other tests are carried out either before hand or until next day to check up on any preciptates on the bottom.

This I could understand by this guy's experience as there really was no visual black dust precipitate on the bottom of the beaker the next day. It was a little tough to make him understand and I too can feel how it may have been for him to digest there actually was no Pd.

yes that is correct - the bowl at the bottom with the black powder in it is actual Pd after reducing the Pd/DMG to Pd

Kurt

A perfect visual for a "to the point" understanding.

The solution with the dissolved metal that you are trying to identify.

For my test, I put a few drops of the metal solution into the white cup, then drop in the stannous. If palladium is present, it makes a very obvious black cloud at once.

Oh now it clears it up

Many thanks for all your responses gentlemen

 

[anachronism]

The solution with the dissolved metal that you are trying to identify.

For my test, I put a few drops of the metal solution into the white cup, then drop in the stannous. If palladium is present, it makes a very obvious black cloud at once.

I'm unsure what you mean Alondro. Could you explain please because when gold is present in decent quantities your Stannous goes jet black straight away. In very strong solutions it also instantly plates out solid gold in a metal sheet on top of the test solution.

As an FYI I use white plastic spoons for my tests, so similar to what you use.

 

[Alondro]

I'm unsure what you mean Alondro. Could you explain please because when gold is present in decent quantities your Stannous goes jet black straight away. In very strong solutions it also instantly plates out solid gold in a metal sheet on top of the test solution.

As an FYI I use white plastic spoons for my tests, so similar to what you use.

It's a green that's so dark it looks black when it first hits the palladium solution. Generally, the palladium-containing parts I have don't have the possibility of containing gold, so there's no confusion.

 

[anachronism]

It's a green that's so dark it looks black when it first hits the palladium solution. Generally, the palladium-containing parts I have don't have the possibility of containing gold, so there's no confusion.

Fair enough - I understand where you're coming from now. All good.