What did I make???

[Sjmenterprise]

So I've been experimenting to get the process down to refine my silver electrical contacts. I had been doing small batches of about 10g at a time til I felt more comfortable. I finally figured out the do's and don'ts (or so I thought) so I did a few larger quantities of 50-100 grams. All went well and I was getting about a 90-92% yield which is about right. I had the contacts tested before hand and that's about what they read on the checker.

Then today I wanted to try and get the copper back. I read somewhere that putting a piece of steel in the copper nitrate will cause the copper to cement. I got all the silver out (or so I thought once again) and ran it through my filters like always. I then dropped an automotive valve spring in the solution. It immediately started reacting and cementing what looked kind of like silver, but it was floating at first and then sinking. I let it do its thing for about 3 hours and when I came back I found the spring covered in a metallic silver coating. I filtered off the solution and got this strange metallic sludge that looks very different than the silver sludge I got before. I put a pic of the spring and mystery sludge.

What is it? Did I not get all the silver out? I left my copper bar in the silver nitrate til it had no reaction with the solution. It doesn't really look like silver tho. Perhaps the valve spring was an alloy of some sort? Are there any metals that would react with copper nitrate to make something like this? Also, there's probably only less than a dozen grams there compared to the 40+ grams of silver that I got out before from the same solution. Whatever caused the reaction quit reacting fairly quickly. Also it took forever and a Sunday to filter it off. This sludge drains liquid MUCH more slowly than typical silver while filtering which leads me to think it is more dense. Any ideas?

 

[g_axelsson]

I always test my nitric salt solution by taking a drop of it and dropping it into salt water, any silver chloride created means I still have silver in solution.

It looks like silver on the spring. Take a bit of the cemented material, dissolve in a little bit of nitric and test with salt or HCl for the presence of silver.

Also test the solution for palladium with DMG.

Göran

 

[Justincase]

I have a large drum I use for my primary waste pot.
It is loaded with copper and left to sit for weeks, then I add sodium chloride the night before siphon off the top portion of liquor.
I then have a second large drum loaded with iron, I to notice similar deposit's on top of my copper deposit's but there was no way it could have been of interest.
The whole point of using sacrificial iron is that it is one of the most reactive elements and it drop's every metal above it.
Look's like nickel deposition to me.

 

[Sjmenterprise]

I did some reading and some brands of valve springs have nickel in them, roughly .2-.4%. When I calculate the weight of a similar spring that hasn't been touched vs weight of the mystery sludge (that is now dry) it comes out to roughly .2%. Interesting. I'll do the salt test in a bit and see what happens.

 

[FrugalRefiner]

The whole point of using sacrificial iron is that it is one of the most reactive elements and it drop's every metal above it.

Justin, iron cements everything below it, i.e., metals that are lower in reactivity.

Sjmenterprise, since you're processing electrical contacts, it could be a variety of metals. There are many different alloys used, depending on the purpose of the contact. The first (and worst) that comes to mind is cadmium, but it could be many others. Just because it's grey doesn't mean it's silver. Do be careful with it. Cadmium is some nasty stuff.

Dave

 

[Sjmenterprise]

Well I ended up getting busy and didn't have a chance to test it. It is for sure not silver tho. Not as heavy as silver and looks much different side by side. I contacted a friend and he is going to test it with his fancy little $30,000 metal alloy checker.

 

[upcyclist]

Well I ended up getting busy and didn't have a chance to test it. It is for sure not silver tho. Not as heavy as silver and looks much different side by side. I contacted a friend and he is going to test it with his fancy little $30,000 metal alloy checker.

If by "fancy little $30,000 metal alloy checker" you mean an XRF gun, you'll need to see what metals it's tuned to. If it's not made for PMs, it will register them as the nearest equivalent it does know about. Ditto for PM-tuned guns and other metals. So, if you take one tuned for use by a jeweler and show it some tantalum, it might tell you it's platinum, or whatever lies nearest it's own pre-programmed numeric value. Picture a periodic table with only some of the elements on it. "Hmm, I don't have atomic number 81, but I know 80 is mercury and 86 is radon. I'll tell this dude that it's mercury." That's an XRF gun (but they don't use atomic numbers).

I can't get too specific, because I'm repeating things I've learned here, hehe, but some of the other guys might be able to explain it better.

 

[jason_recliner]

How about an analogy of an unsuitably calibrated XRF blind tasting emu, kangaroo, snake, crocodile and duck?

Yeah, I know these. That's chicken, venison, chicken, chicken and chicken. Yep. Definitely.