mystery chemical in my recent refining

[mls26cwru]

okay, I have run across an oddity. I have been processing a couple lots of fuzz button wire. I dissolved everything with AR with no leftover residue. I denoxed with sulfamic and diluted/filtered the solution. Added SMB to drop the gold with no problems. after this, things get funny.

upon washing the gold, the first acid rinses are fine. after the second water rinse, it appears i dilute the acid enough that the water turns blue upon sitting for a couple minutes with the gold. a couple more water rinses and it is fine and the water clears up. Do you guys have any experience with this, or have an idea what it could be? Oh, and this is not the pretty blue you get from copper dissolved in nitric... this is a darker, almost dirty looking blue.

I have also tested the gold barren solution left over and gotten positive tests for palladium... but after adding DMG, nothing happens... a whitish cloudy precipitate forms but is quickly dissolved. I have tried diluting the solution, but no luck. I have tried cementation (two small beakers of the solution) with wire and copper powder. the one with the wire is just dissolving the wire. the one with copper powder dropped the same blue material from above along with a silver-ish looking precipitate... both get redissolved after sitting for a while giving me a very deep dark blue solution.

I'm kinda at a loss and scratching my head here guys, so any thoughts?

oh, I also tried adding a couple crystals of ammonium chloride to a drop of solution to see if maybe it was Pt, but I got no color change/precipitate.

 

[kurtak]

Tungsten = looks like blue ink when dissolved in solution

Kurt

 

[Lou]

More likely Mo actually--and it stannous tests orange. For everyone's purposes here...Mo goes into nitric and Aqua Regia, W does not.

 

[mls26cwru]

Thank you guys... From the information I can find, I am expecting Mo to be in the mix, but don't 'think' W should be there.

There was no metal left over after the AR digestion so whatever it is has to be in the solution from the start. The solutions are getting darker the longer I try to cement with copper. Maybe it's causing an oxidation state change in the Mo?

 

[mls26cwru]

i did a bit more digging. its very possible that tungston is also in the fuzz wire... but as gold coated wire. the AR got pretty warm during the digestion, maybe it was enough to dissolve it? Regardless of the element, the most confusing thing is why is it staying clear until after the gold drop? I dissolved everything and the solution was orange/yellow. after the smb, it turned redish/orange. Only after putting copper in it did it start turning dark opaque blue.

 

[Lou]

It's Mo.

 

[samuel-a]

It's Mo.

I agree.
I had the pleasure to refine gold from Au/W fuzz wire (rejects on spools). Tungsten does not go in solution to a significant amount...


Etid: An after thought, it might also be Au/NiCr wire.