Next step after cementation

[Marcel]

I have processed various ceramic CPU pins and remains of other goldplated stuff with HCl+Cl.
Before that I soaked the material in HCl + H2O2 three times, every time replaced the solution.
When the solution remained clear, I was certain that there were no more BMs left, so I started the HCL+Cl leach.
The color of the solution turned green which indicated me, that I did not remove all BMs prior to the leach, but anyhow all the gold was dissolved.
Stannous chloride was strongly positive
I added 2 parts of water and some icecubes, waited some hours then tried the SMB drop.
It failed, so I decided to started "mission emercency" and added a copper sheet. Left it over night.
The next morning the copper sheet was covered with what looks like the brown gold powder.
Stannous chloride now is absolutly negative.
Solution color has turned to yellow.
So after all I now have my gold on that 1 mm thick sheet of copper. What is the best way to proceed from here?
I am afraid if I apply HCl+Cl to that sheet, copper will also dissolve as well and mess up my solution again. Any suggestion?

 

[Geo]

use a catch pan (plastic or glass) big enough to for the piece of copper to fit in. add some water, an inch or two, depending on how big it is and how much powder. the bigger the piece the more water. use a soft brush (like a tooth brush) and gently brush the powder into the water. be sure to dip the brush into the water and keep the piece under water or at least within the catch pan to catch any powder that comes off. normally, cemented gold isnt stuck tightly and should be removed easily.

 

[Marcel]

Thank you Geo!
This is pure magic!
I brushed the copper sheet with a toothbrush and let the dust settle for an hour so far.
Now I can already see the golddust building up on the bottom of the plastic vessel. Clean and starting to clump together - fantastic!

 

[Palladium]

Another trick i use is to place it, i use bar stock, in boiling water and allow the scrubbing bubbles to do the job. :mrgreen: