Gold button refining issue (black Layer).

[Shark]

Beat it flat, thinner than a small coin.

 

[Yggdrasil]

The button refuses to dissolve.
Ive scratched its surface and you can see the gold content, it weighs ~ 0.98g now.
View attachment 57329View attachment 57330
Just peeling off the weird layer and re-AR.

Is this after the AR film you made?
If that is the case I think it might be too much silver in it.

And that is strange since the source material you have described do not contain enough Silver to make a button like this.

As a test put it in a container as small as possible and barely cover it in Nitric, after the reaction stops, then take a drop of two of this nitric and add a grain of salt.
If a dense white precipitate forms you have Silver.

Then you have two options, inquart it to have enough Silver to part it.
Or cheat a bit, since this is a thin flake you can let it simmer in Nitric until no reaction, then move it to AR and repeat there until no reaction.
Use the AR you already have.
After it is completely dissolved, deNOx the AR and treat with Ice, filter and precipitate the Gold.
Drop the Silver with Salt to Silver Chloride and convert to Silver with your preferred method.

 

[Martijn]

It sounds like you have a substantial amount of silver in the alloy making a silver chloride crust.

Sounds like some silver may still be in the button.

Hard to say definitely but I suspect you have a bit of silver in there.

If that is the case I think it might be too much silver in it.

Love it

 

[Yggdrasil]

Love it

A good thing can't be repeated too often you know