E Scrap straight to AR ,my biggest mistake.

[GodLiegeman]

If all you're looking for is to recover gold, then the best option is to remove base metal with sulfuric acid. It won't touch gold at all. The foils will be left as solids. Then you wash them and the plastic/ceramics (since some foils will stick to them with several changes of hot distilled water, and then dissolve the gold using whatever method you can work with.

The HCl-bleach method works very well with gold foils, and you just add a tiny amount of bleach to the HCl at a time (no more than 2-3 mls if you don't have a huge mass of foils) and swirl, until the foils are dissolved. Then it's filtering the junk out of the solution, and washing (save the first wash too, it has a relatively high amount of gold in it), heat outside in sun to remove excess chlorine, and then recover gold with SMB. Always let the soln sit overnight to settle, and bring it to a light boil if it refuses to settle.

I did that method with a small test batch of old (1980's) fingers and pins, and got a full gram of gold from 100g starting material. It was nice dense light-brown powder.

I have about 6g total now of powder, and will be starting on a 1/2 pound batch soon of the highest-grade pins I've got and a little over 1lb of fingers.

Going to try to save nickel in addition to copper, since nickel prices are EXPLODING ($12/lb now!). But that's a complex process for later.

Totally out of topic my friend. Read the post description.Everything went to AR by my mistake.Thats what it's about. How to recover from.

 

[GodLiegeman]

So you split them open and inspected the copper traces inside the fiberglass?

The sim like PCBs did they have chips inside/on them, if so there might be gold in there too.

You do not need to see the metal for the cementing to happen. As long as it is wetted by the solution.

Single layer chips,gold contacts and couple of small transistors

 

[orvi]

Doing AR on the bulk is one of the most serious mistakes, worse is only straight nitric.
Time could reverse the mess sometimes. If you soak all the stuff in AR solution for quite a long time, eventually everything will dissolve and gold will be in solution. Sadly, quite a bit of plastic and electronic components start to decay in that oxidating acidic conditions, leaching various junk into the solution.
Sometimes it isn´t a big deal, sometimes it is determinal.
Anyway... You experienced the most expensive depopulation method just joking, I hope you will get your values out

For first, I would personally try to continue with AR if the bad decision was commited already. Decant the spent solution, replenish with fresh HCl, add nitric, let it sit for two-three days, decant... And in the end, pool every gold containing leach together, cement on copper and go from there.

 

[Geo]

Did ALL metal dissolve in the AR solution? If not, any precious metals will still be in the material. If the tiniest bit of metal remained in the material, leach it again in AR and test the resulting solution with stannous chloride. If all metal did dissolve, Filter the solution and dilute it by adding it to 3X the starting volume with water (tap water will work). Add steel wool which will cement all the metal from solution, including copper. After the solution is bare of precious metals proven by a negative stannous chloride test, allow everything to settle and decant the spent solution. Roast the solids to remove any vestiges of acids and organics. Steel itself contains carbon. The carbon will not dissolve and needs to be removed as well. Roasting will remove the carbon left behind, if it's heated hot enough. After roasting, redissolve the solids in the smallest amount of acids needed. Test the solution with stannous chloride. Proceed by dropping gold first with ferrous sulfate. Ferrous sulfate is perfect for dropping gold from contaminated solution that contains many different metal salts.