decentdude21
Active member
- Joined
- May 15, 2021
- Messages
- 27
Many chemicals are used for precipitating gold from aquaregia like SMBS, Hydrazine hydrate, hydrogen peroxide and ferrous sulfate. Which is best for precipitating gold with 0 loss?
Yes I agree a lot of Ferrous Sulphate is required to drop the gold from AR.Welcome to the forum.
I like smb. It gets everything out. But you will have tiny losses in processing anyway.
H2O2 is an oxidizer.
Copperas takes a lot to precipitate gold from what I've seen.
Thanks for reply.SMB or any sulfite is a winner for me. Practically non-toxic, cheap and very effective. Also easy to tell when you added enough.
Ferrous sulfate has an disadvantage - it contain iron. So when dropping gold, you inevitably introduce a lot of iron to the solution. If we take it more analytically, iron (II) oxidation is one electron process. So for one auric ion, you need 3 ferrous sulfate molecules. This reaction has very low "atom economy", as it is named these days. Simply said, you produce (alongside the product) lots of unwanted sideproducts. Which could in the end contaminate your gold.
Be aware of hydrazine. I work my life hand in hand hydrazine, because I am in organic chemistry and use it a lot as building block. Very nasty, unforgiving, toxic and explosive stuff. Which will reduce not only gold, but also other junk from the solution.
To the 0 losses... It isn´t possible to have 0 losses. Most efficient way how to precipitate metal in quantitative way is make inslouble compound, which could be filtered (like AgCl). Or you can cement the metal with more reactive metal (gold with copper etc.). You will always lost some values, mainly in washing steps of the gold powder with acid. There is practically always some minor loss, but it could be recovered from washes.
Thank youWelcome to the forum.
I like smb. It gets everything out. But you will have tiny losses in processing anyway.
H2O2 is an oxidizer.
Copperas takes a lot to precipitate gold from what I've seen.
I prefer using vitamin C. It's safe enough to eat & no horrible toxic smell like SMB. I read so many posts regarding gold not dropping, I always refine twice as in vids, dirty then clean solution, & up to nowhave not had that problem.
It is a bit more complicated. Remains of nitric acid are still present, but it does have much with redox potential of liquid vs. redox potential required to dissolve the gold back to the solution.I guess that is what happens when you dilute with water then
Depends on how diligently you do your work. And also it depends on ammount of gold. Working in 100 g batch, and losing 100 mg in the process mean that your efficiency will be 99,9%. And it is all possible to accomplish this number with proper dissolution, nitric killing operation, proper settling and decantation and also with recovery of traces of gold from gold powder acid washes.What is the average loss in gold refining? If we treat Aquaregia with SMBS, Vitamin C, Hydrazine Hydrate, and H2O2.
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