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Author: Subject: Brownish orange powder during gold recovery
Ultimum
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[*] posted on 18-12-2017 at 23:59
Brownish orange powder during gold recovery



During my process of recovering gold from scrap electronics, where I immersed boards of 104 old phones in vinegar and hydrogen peroxide, I separated gold foils from the solution. I suspected that some gold may have dissolved in solution because I used HCl at 10% concentration to stimulate reaction between vinegar and H2O2, and from previous attempts I discovered gold in solution. Anyway, this time I added Soda Bicarbonate to the solution and a bit later added SMB but what precipitated was brownish orange powder. The color of the solution was transparent emerald. When I added SMB, the solution turned brownish and slowly into orange - more of brownish orange. What went wrong? what is this powder? It is not an ore - not a metal because it almost weighed a tenth of what gold weighed for the same amount. This is not my first experiment and I obtained gold from previous attempts following the same steps! Any idea what was that? And thanks in advance.

brown orange powder.jpeg - 1.2MB

[Edited on 19-12-2017 by Ultimum]
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Cezium
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[*] posted on 19-12-2017 at 00:17


This looks like a gold, than it probably is gold. Approx. 2g after melting. Powder is bulky and more fluffy so you couldn't expect same density as solid gold.
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barbs09
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[*] posted on 19-12-2017 at 04:47


Is it conductive (to electricity)?

looks like gold powder as Cezium said.
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NeonPulse
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[*] posted on 19-12-2017 at 05:00


This is your probably gold. It looks like it. Try and Smelt it down in your crucible.

Maybe. I thought you needed nitric acid or cyanide to dissolve gold though. Are you following a known process or just experimenting?

[Edited on 19-12-2017 by NeonPulse]




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Sulaiman
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[*] posted on 19-12-2017 at 06:07


Lead oxides can appear from yellow to brown and lead will drop out of solution with the gold using SMB.

I would re-dissolve your product in a little aqua regia;
add HCl to the powder then DROPWISE add H2SO4 to drop the lead as sulphate without creating excess nitrate.
filter, then use SMB to drop the gold.

Depending upon concentrations of Chloroauric acid and SMB, the gold drops out with different appearances,
your photo looks like you added SMB to a concentrated Chloroauric acid solution, less concentrated and it can look just like a black powder.




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barbs09
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[*] posted on 20-12-2017 at 03:18


Stannous chloride test any use to you? Would involve redissolving a small amount.

https://www.youtube.com/watch?v=Hz8odRIqtuQ
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Sulaiman
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[*] posted on 20-12-2017 at 06:25


Quote: Originally posted by Sulaiman  
Lead oxides can appear from yellow to brown and lead will drop out of solution with the gold using SMB.

I would re-dissolve your product in a little aqua regia;
add HCl to the powder then DROPWISE add H2SO4 to drop the lead as sulphate without creating excess nitrate.
filter, then use SMB to drop the gold.

Depending upon concentrations of Chloroauric acid and SMB, the gold drops out with different appearances,
your photo looks like you added SMB to a concentrated Chloroauric acid solution, less concentrated and it can look just like a black powder.


I don't know how I got that post so messed up :(
should have read:

I would re-dissolve your product in a little aqua regia;

add HCl to the powder then DROPWISE add HNO3 with stirring until the gold dissolves,
this prevents excess nitric acid which would oxidise any heavy metals such as lead, preventing precipitation.

To drop the lead out of solution as lead sulphate add H2SO4 dropwise.
filter, then use SMB to drop the gold.




CAUTION : Hobby Chemist, not Professional or even Amateur
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