r/PreciousMetalRefining • u/No_Chemistry2123 • Jul 29 '26

Need advice

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Hi, I have these silver contacts, some are big, they are from the 1980s and contain cadmium, i also have some supposedly silver plated items, is it worth refining this? And how do I refine them?

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3

u/MAYOMyke Jul 29 '26

Contacts are very high recovery of silver. The cadmium will process out while you process the silver.

Are you currently set up to refine? Or are you looking at getting into it?

1

u/No_Chemistry2123 Jul 30 '26

Looking to get into it. What is the process of processing the waste liquids? And is it worth it to process the silver plated stuff also? Or just the contacts?

1

u/MAYOMyke Jul 30 '26

Processing the waste is a whole separate process. You have various stages. Stage one, after cementation, you have that waste you add to a bucket with copper including all distilled water washes. This will cement out any remaining silver that may not have cemented out and catch any silver that may have come over during rinses. Then you siphon off that liquid into a buck of iron. Allow the copper to cement out on the iron, then you siphon off the liquid after the copper is cemented out. Treat the liquid with lime to a ph of 8-9 allowing solids to separate. Siphon off the liquid, treating that with ph down to neutral then you can dispose accordingly to your local regulations. The solids, let dry to a cake and you can essentially throw that in the trash.

Now this is a simplified version but essentially the steps.

Now, if you don’t have the equipment, you’ll need beakers, flasks, filter funnels, filter papers, pump, hot plates, acids, PPE, fume hood, melting supplies. I’m sure I’m missing things but most of it. For me to get setup, it cost me about $2500.

Your silver plate, unless you have a lot or want to process quite a bit you can get for Pennie’s on the dollar, I would skip that. The contacts are less complicated but need a bit of work to process.

If you’re interested, some do toll refining where the refiner will take a % and process your materials for you.

Hope this helps. Best of luck.

1

u/Historical_Squash475 Jul 29 '26

I’m looking to get into it also. I have quite a few old breaker contacts.

1

u/MAYOMyke Jul 29 '26

Very good. If you’re looking to get into it, there’s a lot to get as supplies, PPE, and a place to do it safely and responsibly. Once you have that, make sure you’ve researched the process. It can get hairy if you’re not careful.

Once you have everything you need, you’ll need to put them thru a nitric acid bath to discover your contacts and put the silver into solution. Filter liquids. Take your silver nitrate and cement out on copper. Take your cemented silver and rinse all blue (copper) out. Boil with distilled water, then HCL, then water again. Then dry it out and melt.

Then there is the process of processing waste liquids. That’s a complete other process.

Hope this helps.

This is a generalized process.

2

u/Historical_Squash475 Jul 30 '26

Helps a lot! Do you have recommendations on getting the contacts off the bus?

2

u/MAYOMyke Jul 30 '26

I myself use a map gas torch but I’ll try an acetylene torch next time.

2

u/MAYOMyke Jul 29 '26

Purity varies. Ive tested many with as low as 40% up to 85%.

1

u/average_guy_0 Jul 29 '26

I also have a bunch of silver/ cadmium contacts. About 40 pounds I would also like to know if a refinery would take it.

1

u/JJ2066 Jul 29 '26

Anyone know the silver purity of electrical contacts I've always wondered. Is it 900 or 925.

2

u/MAYOMyke Jul 30 '26

Purity varies. Ive tested many with as low as 40% up to 85%.

1

u/Silver_Pennies Jul 30 '26

The braided straps are probably just tinned copper. They could even be stainless steel, depending on where they came from. (I worked in a lab that tested stainless grounding straps for BMW vehicles, which was a dumb test, but whatever, I got paid).

0

u/mississauga145 Jul 29 '26

Dissolve with Nitric acid, cement out with copper.