Separating Pd and Ag from Tungsten filaments

[Alondro]

I would gladly do something like this - for few minutes, then lose patience But I will very much like to see that under good electron microscope.
THere, it would be probably the one and only place, where having impure and contamined precipitate would be more interesting and preferable - just to observe the few atoms of silver, gold and other PGMs just sitting there alongside with sodium ions from tapwater.

The atoms sue you for spying on them. ;D

 

[anachronism]

This video is only to recover metallic Silver from silver nitrate solution. One could remove dissolved Palladium first using a Dimethylglyoxime process followed by either this process or others depending on how pure you want your Silver.

Apologies I couldn't reply to this earlier because I changed my email and thankfully Frugal sorted this for me (Cheers Dave.)

4metals you're right this isn't the correct video. I'll try to find the one that's applicable.

 

[anarxi]

I would try nitric acid first. Tungsten is relatively stable in nitric solution.

I used to have "scenario" where I refined mixed cut contacts from contactors/relays/switches etc... And some small portion of mixed lots was always sintered tungsten. It never dissolved (like dissolved into the solution), but after longer heating/simmering, they tend to crumble back to powder. I do not know if it was due to some binder metal just dissolving or due to tungsten itself... But it happened. I do not know how would solid tungsten behave as I never had any pure tungsten in my material - always some sintered stuff laced with Mg/Al/whatever other metal.

perhaps it was the so-called “graphite”, silver sintered with graphite, a fairly common thing in automatic electrical switches and contactors...
Tungsten contacts are often found in low-current relays and vibration transducers. After nitric acid they remain quite shiny and can even be confused with platinum contacts.(pt/ir 10)
but after the fire they darken, sometimes a rainbow appears.

 

[FrugalRefiner]

Apologies I couldn't reply to this earlier because I changed my email and thankfully Frugal sorted this for me (Cheers Dave.)

Happy to be able to help.

Dave

 

[orvi]

perhaps it was the so-called “graphite”, silver sintered with graphite, a fairly common thing in automatic electrical switches and contactors...
Tungsten contacts are often found in low-current relays and vibration transducers. After nitric acid they remain quite shiny and can even be confused with platinum contacts.(pt/ir 10)
but after the fire they darken, sometimes a rainbow appears.

I also had sintered tungsten ones. I did XRF of them multiple times - insoluble residue after nitric. And I only seen tungsten + some very minor other elements.
I know about W-Al sintered pieces in diodes (these look like solid tungsten, but if you will do XRF, it will clearly see also Al). But this is different looking and behaving in acid.

But you answered main question and solved the issue - nitric won´t appreciably attack solid tungsten.