Ag in AR

[mosfetta]

ciao, no, non va bene, soprattutto con le schede dei telefoni cellulari.

I PCB dei telefoni più vecchi contengono molto piombo nelle saldature, quelli più nuovi conformi alla direttiva ROHS contengono molto stagno.

È necessario separare tutto dall'ordinamento PCB e lavorare con ogni materiale separatamente

È necessaria una quantità molto elevata di PCB per recuperare una quantità significativa di PM e l'operazione richiede molta manodopera.

Devi sbarazzarti della saldatura per lavorare tu stesso per recuperare i PM, altrimenti ti ritroverai con un gran pasticcio con ogni spazzatura nella tua soluzione.

La saldatura può essere rimossa con bagno HCl.

Pietro

Thanks

 

[mosfetta]

As advice for a basic recovery system this is sound, however using the correct mix of AR solution there is no re-deposition at all. Also, the losses would be minimal if any at all if done correctly.

"using the correct mixture of AR solution no redeposition occurs"

what do you mean by correct, I do classic AR 1/3

 

[Yggdrasil]

As advice for a basic recovery system this is sound, however using the correct mix of AR solution there is no re-deposition at all. Also, the losses would be minimal if any at all if done correctly.

Hm, interesting.
Can you elaborate a bit?

 

[anachronism]

"using the correct mixture of AR solution no redeposition occurs"

what do you mean by correct, I do classic AR 1/3

"Classic AR" shouldnt be used as a standard for electronics waste. That doesn't apply. Yes there are circumstances when it's used (and in some even stronger) but the classic AR approach fitted carat scrap where you had known quantities of metals.

 

[Yggdrasil]

"using the correct mixture of AR solution no redeposition occurs"

what do you mean by correct, I do classic AR 1/3

We consider any mix of Nitric and HCl as AR.
For small scale projects without time constraints we use High amount of HCl and add just the Nitric needed to accomplish the task.

 

[anachronism]

Hm, interesting.
Can you elaborate a bit?

Certainly Ygg. If you have a good quantity of boards with visible gold on them it's perfectly acceptable to use AR, because provided you keep the oxidiser level up, you can effectively clean the boards without drama because the gold is constantly being oxidised. Dissolve the surface gold and underlying strips, remove the "cleaned" board and rinse in another vessel. Then use the rinse back into your AR or to begin another batch.

The key is to keep your AR live and active.

 

[Yggdrasil]

Certainly Ygg. If you have a good quantity of boards with visible gold on them it's perfectly acceptable to use AR, because provided you keep the oxidiser level up, you can effectively clean the boards without drama because the gold is constantly being oxidised. Dissolve the surface gold and underlying strips, remove the "cleaned" board and rinse in another vessel. Then use the rinse back into your AR or to begin another batch.

The key is to keep your AR live and active.

I guess circulation so the most saturated Gold bearing solution are moved away quickly help too?

 

[goldshark]

Just wondering if there are dissolution rates, for various metals. In other words, does Au dissolve faster then Tin in AR, or does Tin dissolve faster? Same for other metals. I have never seen chart for the reactivity for varying metals in AR, or if they all dissolve at the same rate.

 

[Yggdrasil]

Just wondering if there are dissolution rates, for various metals. In other words, does Au dissolve faster then Tin in AR, or does Tin dissolve faster? Same for other metals. I have never seen chart for the reactivity for varying metals in AR, or if they all dissolve at the same rate.

Slightly bad example since Tin really do not dissolve, but rather converts to our "friend" Metastannic acid.

 

[anachronism]

I guess circulation so the most saturated Gold bearing solution are moved away quickly help too?

If it's hot - which it should be then it recirculates itself quite merrily Ygg.

 

[Yggdrasil]

I just realized that this thread is about Silver in AR, which will almost not happen.

 

[mosfetta]

I notice that in this environment we never stop learning, discussing and learning from you.

 

[mosfetta]

We consider any mix of Nitric and HCl as AR.
For small scale projects without time constraints we use High amount of HCl and add just the Nitric needed to accomplish the task.

 

[oneslade]

You need to study more.
When ever there is Chlorides present, Silver will not dissolve, it just forms Silver Chloride.
So if it is over 7.5% Silver or around there, the Silver Chloride formed will protect the Gold and nothing much will dissolve.

When this happens what's the best plan for correction?

 

[Yggdrasil]

When this happens what's the best plan for correction?

Welcome to us.
When ever the Silver content is too high, we add more Silver or Copper so the amount of Gold goes below 25% (Quart)
hence the term inquarting.
Then the alloy is parted which means we dissolve the non gold part in Nitric.
This leaves us with a solution of Nitrates (Silver, Copper and what not) and some Gold as metal.
The Gold is then dissolved and dropped as powder or melted directly depending on the intent of the one processing it.

Her is something for you to study:

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: https://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=19798
2. Then read the safety section of the forum: https://goldrefiningforum.com/forums/safety.47/
3. And then read about "Dealing with waste" in the forum: https://goldrefiningforum.com/threads/dealing-with-waste.10539/

Suggested reading:
https://goldrefiningforum.com/forums/the-library.101/
https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
https://goldrefiningforum.com/threa...le-read-this-before-you-post-about-ore.33333/


Forum rules is here.
https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/