Need help with processing GF

[USAgold32]

Hello,
I am needing a little guidance on processing my lot of 12 1/10 12kt GF glasses frames. I have dissolved most of the scrap metals from the frames with dilute nitric. I have filtered the contents a few times but still have quite a bit of black particles mixed in with the foils and gold pieces. I was wondering if these black particles would effect the gold solution once processed with AR. I have roughly 20grams of gold flakes and gold pieces left from the frames. I have worked the frames with dilute nitric three times to dissolve as much scrap metal away from the gold as possible. I was unable to filter off some of these black particles. Should I just process the lot with the black particles or use a pair of tweezers to pick out the foils and gold pieces? Any information would help thank you.

 

[steyr223]

I know very little of gold filled
I guess this thread will teach me cool 8)

What i do know....are the black particle metsl
Is there any base metal left
I guess since your only at the nitric leach stage
The base metals might not be an issue
But it is common practice to get complete dissolution
Any ways if the black pieces are not metal then they'd
Stay solid when the gold was oxidized(dissolved)
And can easily be filtrred out
Even tbough there are certain types of plastic AR
Can make a mess out. Of so i would test a
few pieces in your ar and make sure they dont get gooy

I would wait for better advice from the druids
Here on the form
Hope this helps
Steyr223 rob

 

[MGH]

I think I'm going to disagree with Rob. I don't think your particles could be plastic since you're only processing gold filled material. Actually I think your particles are gold. It's not uncommon for gold plating (or thin parts of gold filled) to turn to bits of powder once the base metals they were attached to are removed. Just keep going through your refining process and keep the powder with your flakes and foils. If the powder is gold, it will behave like gold. If it's something else, it will get filtered out or washed out eventually.

 

[Lino1406]

Use a sample of the black particles with AR
if you get yellow color it probably contains gold

 

[butcher]

If done as above, the material dissolved, nitric was not used in excess and eliminated from the acidic solution, a stannous test could then verify if any gold went into solution.

 

[Eaheisler]

correct me if I'm wrong but, if you go through your nitric wash and are left with particles that are undissolved you should pull them out to find out why they didn't dissolve. If a 2nd wash creates a chemical reaction than your nitric was was incomplete the first time.

 

[vegaswinner]

Eye glasses can I believe be a little more problematic than just standard rolled gold. Did you separate the frames, remove any plastic nose pieces, remove the ear piece as these are usually stainless, remove any obvious solder repairs and incinerate before nitric treatment or did you just process the whole frames in nitric? Lasersteve has commented on eye glass frames saying they contain trace amounts of rhodium. I don't know if it could be this... If you are getting no more reaction to nitric then I would proceed to AR and just digest everything else thats left then test, filter, drop and clean as per usual.

 

[Palladium]

Those black particles are sometimes pieces of stainless that will partly dissolve. Those little black pieces will dissolve in ar on the next go around. Keep all solids from the nitric process except pieces of stainless that can easily be removed and washed and pieces of obvious plastic or something you may need to remove as trash. The ar process will clean it all up and the rest is caught in the filter as trash. When i do the ear pieces with stainless i run them straight in ar. The stainless is fairly thin and springy in the ear pieces. The ar will eat those stainless pieces away, but the trick is a prolonged heating cycle with a high hcl to nitric content. As you add nitric in increments you allow the nitric to be exhausted and the hcl ratio to increase. As the nitric is exhausted in cycles you allow a long break between cycles so the stainless has time to be attacked. The first step in this type of process is not considered refining, but recovery. Refining takes place later.