What did I do wrong?

[Bertho]

Thanks!
I kept thinking that there is also iron in the mix but I just realized it is in the solution that gets filtered away.
Bertho

 

[butcher]

Yes, CuCl2 and FeCl3 can be in solution together, as well as CuCl and FeCl2, as well as the other more reactive metals below copper...

In a solution, we can have a very large mix of positive metal ions (cations), and also could contain a mixture of salt ions from different acids (anions) as well as unreacted metal or acids...
Reacting with each other...

 

[Bertho]

I siphoned off the liquid from the precipitate which as expected looked like copper.
I spooned up about 2ml of the wet material and rinsed it. After settling, I poured off as much as possible of the rise water and dried it on a hotplate.
To get rid of any acids I placed it in an electrical oven at 500°C for 20 minutes.
I then added 50% diluted nitric acid and most of it dissolved.
I rinsed the orange/brownish residue. It has very small, slowly setting particles.
After pouring of the rinse water I added HCl and then nitric to dissolve the residue in AR.
Nothing happened!! No reaction at all!
On the spot plate is a sample before and after adding stannous chloride.
The beaker shows the color.

What is the mystery residue?
How do I proceed to find the gold that might be in there?
Bertho

 

[Bertho]

Update: After the liquid has been sitting for 12 hours:
The orange/brown sediment is still there but it has now settled and the liquid is yellowish and clear.
When adding the stannous chloride a dark gray spot is slowly formed over maybe 10-15 seconds.
Bertho

 

[butcher]

I cannot see it, so I do not know.

Iron can form insoluble oxides (like rust) which would look orange-brown, if put into solution would be yellow to green or even brown in solutions depending on the oxidation state of the iron...

Read Hoke's book, around page 100 she gives two methods to test for iron in solution.

 

[Bertho]

I do not have those testing chemicals available described by Hoke.
As a test I wrapped up a sample of the sludge in a piece of assaying lead foil and placed it in an assaying cupel at 1100C. Some of the content was absorbed as expected but there was a bead left, too big to be gold. It was presumably undissolved copper.
I place the bead in muratic acid and it was complacently dissolved.
My conclusion is that there is no gold in the sludge and that the yellowish looking solution is the dissolved iron.
Thank you for helping.
Bertho