golddigger2
Well-known member
- Joined
- Sep 25, 2009
- Messages
- 104
Hi all
I had a batch of about 50 nicely plated circuit boards(see photo) I used A/P to de-plate the gold, the gold particles were very very small and after stripping I filtered the A/P the gold was so small that you could not see the granular texture of the gold. I have used the A/P process many times before with good results but i had never attempted these type of boards before. After filtering I was left with a gold coloured powder(unfortunately no photos) I know there was considrable gold in this mix as I saw how much was being washed from the boards. I used HCL/clorox and filtered the, resulting liquid was very green, so I assumed there was copper in the liquid. I added about 60 grams SMB which should have been more than enough to precipitate the gold in solution. The solution turned clear as usual but then the gold didnt drop. I guessed that the chlorine was inhibiting the precipitation process and so left it for a couple of days to see if it would precipitate on its own. I then heated the liquid to see if that would start it. After heating about 6 litres of the solution it began to precipitate. I left it for another 2 days and when i went to siphon off the liquid I noticed a thin brown film floating on top of the liquid so i added a little more SMB but it didnt change much. I filtered some of the liquid and noticed that the water drops falling from the jug when they fell in the bucket of SMB solution that they were giving off a brown stain when they hit the solution. after about a minute I noticed that the filters were turning a cherry pink colour (see photos) I have never seen this before and am not sure what to do next. The SMB solution was still positive for gold but the stain was more brown than purple.
I had a batch of about 50 nicely plated circuit boards(see photo) I used A/P to de-plate the gold, the gold particles were very very small and after stripping I filtered the A/P the gold was so small that you could not see the granular texture of the gold. I have used the A/P process many times before with good results but i had never attempted these type of boards before. After filtering I was left with a gold coloured powder(unfortunately no photos) I know there was considrable gold in this mix as I saw how much was being washed from the boards. I used HCL/clorox and filtered the, resulting liquid was very green, so I assumed there was copper in the liquid. I added about 60 grams SMB which should have been more than enough to precipitate the gold in solution. The solution turned clear as usual but then the gold didnt drop. I guessed that the chlorine was inhibiting the precipitation process and so left it for a couple of days to see if it would precipitate on its own. I then heated the liquid to see if that would start it. After heating about 6 litres of the solution it began to precipitate. I left it for another 2 days and when i went to siphon off the liquid I noticed a thin brown film floating on top of the liquid so i added a little more SMB but it didnt change much. I filtered some of the liquid and noticed that the water drops falling from the jug when they fell in the bucket of SMB solution that they were giving off a brown stain when they hit the solution. after about a minute I noticed that the filters were turning a cherry pink colour (see photos) I have never seen this before and am not sure what to do next. The SMB solution was still positive for gold but the stain was more brown than purple.
