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What metal are these contact?
- Thread starter John Tol
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I don't want to be harsh or anything.
But how in the world can we answer this question based on these pictures?
It can be Ag, W, Ag/W, Ag/Pd and so on, based on what they contain at times.
Do you have picture of the breakers, where did they come from?
Do you have access to Nitric or Schwerters solution?
Information is central to answering any kind of question.
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Hi Yggdrasil,
Thanks for your reaction.
I do not have more info or pictures on this. All circuit breakers have been dismantled. They came from a switch board.
The question came up as I can recognise gold or silver contactpoints, but these look weird at the contactpoint. It was more that anyone could recognise these at a first glimps.
I could test with nitric, yes. Can you give a hint how?
Thanks for your reaction.
I do not have more info or pictures on this. All circuit breakers have been dismantled. They came from a switch board.
The question came up as I can recognise gold or silver contactpoints, but these look weird at the contactpoint. It was more that anyone could recognise these at a first glimps.
I could test with nitric, yes. Can you give a hint how?
Try to dissolve a small piece.
If you then drop a few grains of salt into it it will create a white solid, Silver Chloride.
And then you can try a stannous test for Pd.
The stannous is sensitive for Pd, Pt and Au.
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Ok Thanks, I will give it a try and let you know what comes out.
Regards, John
Regards, John
kurtak
Well-known member
They do not look like they came out of "breakers" (at least not to me) they look more like they came out of magnetic disconnects
If they are out of magnetic disconnects - then they are more then likely 90% (plus) silver --- & likely alloyed with 10% (or less) copper &/or cadmium
Your pics are a "top view" only
please provide a pic looking at them from a "side view" & as well a pic looking at the bottom of them
Kurt
If they are out of magnetic disconnects - then they are more then likely 90% (plus) silver --- & likely alloyed with 10% (or less) copper &/or cadmium
Your pics are a "top view" only
please provide a pic looking at them from a "side view" & as well a pic looking at the bottom of them
Kurt
Ohiogoldfever
Well-known member
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I’d touch off an edge with a fine file. Seeing what’s under the oxidation
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Drop one to the nitric. If silver, upon heating it will slowly dissolve. As Yggdrasil said, if silver is in solution, by adding salt water or HCL you get quark-like precipitate of AgCl.
Contacts are often pressed powders or sintered materials of carbon, tungsten , nickel and silver. Various ratios of elements. If you take one with pliers and it crumbles or break to the pieces upon squeezing/pressing, it is this type of contact. If it just deform as metal should, then it is probably AgCd or AgCdO alloy. If it is magnetic, then it is sintered material with Ni or other ferrous element.
Pd will give you colouration depending on other contaminants - but it is usually dirty green due to copper. Pure palladium in solution is orange to reddish brown to brown (depending on concentration). Do not mistake that colour with possible iron. Stannous would be helpful
Contacts are often pressed powders or sintered materials of carbon, tungsten , nickel and silver. Various ratios of elements. If you take one with pliers and it crumbles or break to the pieces upon squeezing/pressing, it is this type of contact. If it just deform as metal should, then it is probably AgCd or AgCdO alloy. If it is magnetic, then it is sintered material with Ni or other ferrous element.
Pd will give you colouration depending on other contaminants - but it is usually dirty green due to copper. Pure palladium in solution is orange to reddish brown to brown (depending on concentration). Do not mistake that colour with possible iron. Stannous would be helpful
kurtak
Well-known member
IMO - those points are not worth the time & chemicals required to process them
You have a very small (plus/minus) 1/2 gram silver cap (point) that is soldered/brazed on top of an iron (alloy) rivet which is larger then the actual silver cap
It takes 4 times more acid to dissolve base metals (copper, iron etc.) then it takes to dissolve the silver
So IF (the BIG IF) you drill the back side of the rivet (to remove the rivet from bus bar) you still have some rivet to dissolve along with the silver cap --- it will cost more in acid to dissolve the rivet plus silver cap then the silver is worth & that does not include your time
If you nip the bus bar close to the point then you have some bus bar + rivet + silver cap to dissolve = even more acid (cost) plus time
As Hokes says in her book --- "the silver - if worth while" --- this is a classic case where the silver is not worth while
IMO - it will cost you more in acid - let alone your time - to process these points - then the value of the silver
As a wild guess - cost of acid will be (plus/minus) two times more then the value of the silver - plus your time AND we have not even talked about the cost dealing with cleaning up the chemical waste when done with the silver recovery part of the process
Kurt
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Ok, Kurt,
I understand completely.
I should just collect (much) more of these to make it worth.
No problem, I had no intentions to stop with my hobby.
Thanks for your advice.
I understand completely.
I should just collect (much) more of these to make it worth.
No problem, I had no intentions to stop with my hobby.
Thanks for your advice.
Depends. You do not need to directly dissolve everything. For beginner, it is rather difficult to put together right setup for melting this material (as Cd could be present in it) - but it is fairly doable to melt it all in one pot and then decant off the melted metals, leaving ferrous carriers in the crucible. Nowhere near quantitative - but you will use no acid to concentrate the values, which will be too costy to process with acids. However, I think the cost of acid won´t be that extreme. If we consider it could be digested in nitric/sulfuric mixture - you will only spend nitric for iron oxidation. Sulfuric will act as counterion to iron.
It is done in a way that you add some lead to the smelt to lower m.p. of silver, and to get appreciable volume of material to begin with. Then, melt is poured off the iron and additional lead is added, process of "stripping" repeated and resulting lead pour is saved for the "stripping" of next batch.
Lead is then cupelled away, and you are left with a compact dore, which can be then acid-refined with your preferred method. Solubility of iron in AgPb melts is quite low, so there would be nice separation.
In the case contact points contain AgCd alloy - you will need to scrubb the toxic CdO fumes with appropriate scrubber. If the material is sintered AgC, then you will need to either properly incinerate the carbon or prolong holding time in the crucible with plenty of stirring to decompose AgC matrix and dissolve the silver into lead.
It is done in a way that you add some lead to the smelt to lower m.p. of silver, and to get appreciable volume of material to begin with. Then, melt is poured off the iron and additional lead is added, process of "stripping" repeated and resulting lead pour is saved for the "stripping" of next batch.
Lead is then cupelled away, and you are left with a compact dore, which can be then acid-refined with your preferred method. Solubility of iron in AgPb melts is quite low, so there would be nice separation.
In the case contact points contain AgCd alloy - you will need to scrubb the toxic CdO fumes with appropriate scrubber. If the material is sintered AgC, then you will need to either properly incinerate the carbon or prolong holding time in the crucible with plenty of stirring to decompose AgC matrix and dissolve the silver into lead.
Sawtooth7
New member
I'm new to the forum but just had a conversation with a guy who's an electrician and scrapper about those exact round contacts. From what he said, the round part alone is "near"pure silver. And though the other parts contain silver they are alloyed with other metals. I have an acid test kit for gold and silver I got off Amazon for like 20-30 bucks. It's not exact but could help you confirm if your looking at silver and approximate the purity level.
Normally, the contacts are alloyed.
It's silver (50 to 90%) mixed with tin oxide (SnO), cadmium, palladium, nickel or whatever in order to increase the durability. Some are gold plated.
The test kits won't tell you what's mixed in.
You might be able to snip off the caps with this tool or something similar....maybe. You'll probably still have some base metals to deal with.
I have something similar but I had to modify mine to get the cutting edge closer to the surface. I had to grind away the flat areas down on a grinder. You'll probably have to do the modification, because I have never found one with the cutting edge close enough.
https://a.co/d/8CUa1ne
I have something similar but I had to modify mine to get the cutting edge closer to the surface. I had to grind away the flat areas down on a grinder. You'll probably have to do the modification, because I have never found one with the cutting edge close enough.
https://a.co/d/8CUa1ne
For the riveted contacts, I'm using a smaller (but heavy duty) side cutter.
I place the tip of the side cutter to the middle of the contact, cut the bus bar and spread the bus bar until the riveted contact comes loose.
I place the tip of the side cutter to the middle of the contact, cut the bus bar and spread the bus bar until the riveted contact comes loose.
Ohiogoldfever
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I’m my opinion it’s all worth collecting. Kept in a safe place waiting for the day when market manipulation allows it to raise enough to be worth while. If that’s never, we’ll I’m only out a bit of time in my efforts.
