MarkM
Harmless
Posts: 1
Registered: 27-6-2025
Member Is Offline
Mood: No Mood
|
|
Genius Chemist Needed
So I had some scrap gold laying around ~14k. According to the trusty niton, other ingredients (impurities) in the scrap included Ag, Cu, Zn, Sn, ...
etc.
What I typically do and what I was supposed to do: Melt the scraps into tiny beads to increase surface area. Boil [HCl]. Add the beads. Let that cook
for a day. That results in a solid and a liquid (solution). The resultant solution contains most of the impurities. The solid, for the most part
is Au and Ag. I pour off the liquid at this point and then add the solids to aqua regia (AQR). After the AQR dissolves the gold/silver, I
precipitate the gold with Sodium metabisulfite (SMB).
What I actually did. I melted the scrap into tiny beads. I added the beads to AQR. Everything went into solution. I then quenched with SMB.
Something precipitated out and that precipitate didn't test gold (stannus chloride). It was at this moment, Mark new he F**KED UP.
I left the precipitate in the beaker and allowed the solution to fully desiccate leaving just the mix of SMB, AQR, and impurities in a solid state.
My question: In order to accomplish the same goal (gold purification) how should I proceed? It seems too easy if I can just take the mix, add it to
[HCL] and start the process over again, but maybe it is that easy?
I am all ears. Thank you in advance.
[Edited on 30-6-2025 by MarkM]
|
|
|
Radiums Lab
Hazard to Others
Posts: 299
Registered: 18-3-2025
Location: India
Member Is Offline
Mood: Experiencing the elegance of science.
|
|
Welcome to SM. The ppt. does not respond to SnCl2 , Au needs to be in the solution to show +ve test.
Water is dangerous if you don't know how to handle it, elemental fluorine (F₂) on the other hand is pretty tame if you know what you are doing.
|
|
|
Radiums Lab
Hazard to Others
Posts: 299
Registered: 18-3-2025
Location: India
Member Is Offline
Mood: Experiencing the elegance of science.
|
|
Anyway some images would help.
[Edited on 30-6-2025 by Radiums Lab]
Water is dangerous if you don't know how to handle it, elemental fluorine (F₂) on the other hand is pretty tame if you know what you are doing.
|
|
|
walruslover69
Hazard to Others
Posts: 243
Registered: 21-12-2017
Member Is Offline
Mood: No Mood
|
|
The best thing about inorganic chemistry is that you can dissolve everything back up and try again! Pictures would be useful. do you have 100%
certainty that you starting compound is gold?
|
|
|
zed
International Hazard
Posts: 2316
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
Member Is Offline
Mood: Semi-repentant Sith Lord
|
|
Ummm. You might want to rid the solution of Silver first.
Now, Silver dissolves in concentrated Aqua Regia, but when the solution is diluted, it precipitates out as AgCl. Which tends to display a rather
purplish color.
Here, I suggest hot Aqua Regia be added to hot water. Hopefully, this will increase the size of the AgCl crystals so they can be filtered out of
solution. When AgCl is formed at cooler temperatures, it tends to form a nasty Colloidal Ppt. that must be boiled interminably, in an effort to
enlarge crystal size, and render it filterable.
But then, I don't know a lot about refining gold. Worth a try?
[Edited on 10-7-2025 by zed]
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
