flatpacks dmg brown

[solar_plasma]

Have run flatpacks:
incenerated
washed
HCl
NaOH
incenerated
4M HNO3 (a little H2O2 3% after some days)
filtered

Now I have tested the filtrate for pgm with dmg and for Ag with NaCl.
Ag was negative. No wonder, since I have found a lot of copperparts which have not dissolved yet.
DMG was positive, the CuNO3-typical blue solution turned immediately brown. edit: I was confused about testing, when I wrote this. DMG should be used in spotplate or a maybe a test tube and would give yellow pricipitate with Pd. It is also used to test Ni
I have to give the flatpacks a new round HNO3 in order to dissolve the remaining copper, but why do I get a brown reaction(from blue) with DMG. All pgm's should have cementated back. What is it? Palladium? Or an artefact?

 

[vegaswinner]

DMG also reacts with nickel, I don't know but it could be that. If it was palladium it would be orange and platinum would take some days a week to react

 

[solar_plasma]

maybe an artefact...a piece of copper for eventually cementation will show it..

Since I have another kg of flatpacks now and maybe soon one more kg flatpacks and s/n-bridges again, I guess, I will wait for the next batch to be ready for HNO3-step and process those all together.

 

[samuel-a]

Solar

Try testing with dmg in a tesf tube. Might help you better identification of the ppt colors.
Make sure your test sample is acidic too.

 

[solar_plasma]

Solar

Try testing with dmg in a tesf tube. Might help you better identification of the ppt colors.
Make sure your test sample is acidic too.

In a tube it turns from blue to dark brown-green without precipitate so far. I guess I have to make an alkaline DMG-solution. I read before, that the alcoholic solution is sub-optimal.

Thank you, Sam!

 

[patnor1011]

DMG also reacts with nickel, I don't know but it could be that. If it was palladium it would be orange and platinum would take some days a week to react

This is simply not truth.

*edited
Ah OK, my bad, I had orange fixed with stannous and Pt.
So he is correct in a way but I would say that Pt in DMG will show up as yellow.