A/P problem acid wont remove copper

[lunar4772]

My problem is I had three seperate AP batches going and stripped the gold from them all I was doing Pins / fingers / and a few chips. I mixed the foils, pins and cpu gold together before doing the acid wash and now the acid does not seem to want to strip the remaining copper at all. I can actually see copper color in the mix. The acid looks murky and is extremely slow to filter.
The filters plug quickly. So far I have tried acid washes, lots of water washes and filtering but I can't get rid of whatever I have gotten into my soup that seems to stop the acid from working. Any suggestions anyone?

 

[lazersteve]

Mixing unknowns in AP is a hit and miss proposition.

I would guess you have either formed a saturated solution of copper I chloride or you have included too much iron or tin in the mix and fouled the solution.

Too much copper I chloride can be solved with more HCl and small additions of air or peroxide until the solution turns a very light green or blue-green. You can test for copper I saturation with a splash of tap water, if the addition of a little water forms a white cloud in the dark sludge it's saturated with copper I chloride.


If you fouled your AP with iron then you'll need to start with a free batch. You can use HCl and water to thin the thick fouled solution and filter out and foils or gold powder.

Steve

 

[lunar4772]

The problem was me I was trying to hurry things along too much. I have added more hcl and some peroxide and it seems to be working fine again. Its my last batch for a while and I was trying to get things cleaned up.
Frank