Brown powder composition

[MicheleM]

Hello everyone,
Good morning/afternoon /evening

I followed the CuCl2 process described in the forum to recovery some gold from a small amount (less than 200g) of magnetic and non magnetic pins (not fully plated) (see for example image 1 and 2 ). i tested the solution with stannous and the test was negative. Then i collected all the material that remains after the filtering process (I rinsed with water- HCl- water ) separately for magnetic and non-magnetic pins (figure 3 bottom view , figure 4 top view ). from the Top view is visible a lot of brown/dark brown (not black) material, that is not soluble in 34% HCl.
In my opinion should not be Copper salts (i dissolved Copper 1 chloride during the process adding more HCl) or silver.
I would like to know your opinion on what it could be.

Thank you for your attention,
have a nice day

 

[nickvc]

Probably material from the magnetic pins that won’t dissolve in HCl , I wouldn’t worry to much just dissolve your gold and precipitate it by the method of your choice, if your gold precipitate looks dirty re dissolve and precipitate again.

 

[MicheleM]

Thank you very much for your response nickvc.

Sorry if my question sounds dumb ,but i m very curious about everything I see for which I have not an acceptable response.

Have a good day/night!

 

[ZiegenSauger]

Hello MicheleM,

I am a novice refiner and been through this scenario quite recently. Actually the source material was about 175g of magnetic and non-magnetic material like pins and terminators.

I do not know what the dark blue dirt is, I just filtered, washed well and dumped into Aqua Regia to drop the gold. Part of the brown dirt remained, part dissolved ( I re-dissolved again later to make sure nothing good was left).

Among the many many learnings from the folks and threads here is just not to care much about the uncertainties. Just proceed, put aside whatever left-over liquid or solid you might have, then return to them later when you have time or enough accumulated for processing.

Let me know how it goes, for sure I will learn quite a bit from your experience since I have been collecting a lot of plated pins (a lot means between 100/200 g every other month )

Cheers and good luck

 

[MicheleM]

Dear ZiegenSauger ,
thanks very much for your reply and hints,
i will keep you informed of updates,
Actually I'm planning to process others magnetic pins (a very small quantity) with the same protocol to reproduce the impurities and , if (i hope not ) things will go wrong with the exponential growth of Covid cases , i will have a lot of spare time to try some experiments on it.

Have a good day!

 

[MicheleM]

Dear ZiegenSauger, good morning
some news since october:
Image1 :

the beautiful orange solution comes from the jar shown in the beginning of this thread, the one with unknown "brown stuff" (AP method applied on magnetic, non magnetic pins and 10 RAM stick and then HCl-Cl)

The yellow one comes from full-plated pins ( sulphuric acid cell and then HCl-Cl)

the heavy-copper-contaminated green one is my "training solution" to learn gold refining and re-refining. ( foils from RAM stick and CPU gold plated pins that i dissolved straight with the HCl-Cl method)


Finally i have time to do experiments with potassium metabisulfite and the green solution, as you can see in Image3 and image4, the precipitated powder is still copper contaminated and it waits for re-refining and "Harold washes".

Image3:
image4:

Image5 , on the right side of the picture you can see the yellow solution obtained dissolving the powder of image4 in HCl-Cl, looking to the yellow color the powder was less copper-contaminated than i thought. Left side, the pale blue solution is the former green solution after precipitation.
image5:

 

[MicheleM]

I forgot to say that i add just a little bit of diluited sulphuric acid before precipitation (eventually for lead) , and that i collected all the remaining fraction of the unknown "brown mud" that survived in order to chloridric acid, CuCl2, and then Chlorine, it could be Silver Chloride? i will try concentrated and diluited sulphuric acid, and in case of negative stance i will give up

Good morning/afternoon/evening to all the forum members, have a nice day