497
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precious metal refining
http://shorinternational.com/subzeroinstr.htm
interesting stuff, what i want to know is what the "SubZero" stuff is? "nitric acid replacement powder" i take it it must be some kind of nitrate.
also i wonder what the "Storm Precipitant" is. it would be nice to know because i'm sure they're making a healthy profit on common OTC chemicals. i'd
love to try extracting some gold and platinum some time but i'm sure as hell not going to pay $500 or whatever they want or those things.
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12AX7
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Ya, probably one of the common three cations: potassium, ammonium or sodium nitrate. The price appears to be a lot less than $500, but the price per
pound is still silly. "Storm" is probably a lower sulfate, like sulfite, dithionite, etc.
Tim
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497
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hmm thanks, and i was talking about the price of the whole apparatus. I might just have to make some nitric acid and make some real aqua regia.
also does anyone know how much gold/platinum can be dissolved in a liter of aqua regia?
[Edited on 9-12-2007 by 497]
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garage chemist
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Sodium nitrate would make most sense.
Ammonium and potassium ions form very sparingly soluble hexachloroplatinates and hexachloropalladates, so you dont want those in your aqua regia if
you want to dissolve platinum and/or palladium.
That site just exploits people who have no idea of chemistry, as they are common today. If people knew about the chemistry involved, they would never
buy trademarked overpriced salts and just buy the plain chemicals.
Conc. HCl and NaNO3 would make a good and useable aqua regia, just somewhat more dilute than the real thing.
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497
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thank you! i found an interesting patent on the subject also, it talks about extracting the gold from aqua regia with methyl isobutyl ketone. then
converting it to gold hydroxide woth a NaOH solution. the Au(OH)3 is then reconverted to HAuCl4 with HCl and precipitated with sodium sulfite
(probably what their "storm precipitant" is).
the patent also says the scrap gold can be made into chloride by boiling it in 6N HCl. i assume that proceeds much slower than with aqua regia.
it also mentioned using ammonium hydroxide instead of NaOH which is supposed to increase the purity by forming insoluable salts with other metals like
garage chemist said. the problem is it makes fulminating gold, and it doesnt say any more on that subject.
MIBK is not easy to find from what i've seen, but it is available, i don't know if there's an OTC source though. maybe it's not needed, i'm not sure
how much the whole process helps.
ok i found it: United States Patent 4297134
[Edited on 10-12-2007 by 497]
[Edited on 10-12-2007 by 497]
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12AX7
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NaClO3 in small amounts can also be used, forming chloric acid in solution which readily disproportionates to dissolved Cl2 gas. Oh, that reminds me,
I should say something about that in another thread...
Tim
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noxx
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Don't buy the SubZero stuff. You can do the same yourself for much cheaper.
Interested in precious metals refining ? Visit www.goldrefiningforum.com
We have tons of video tutorials and written tutorials as well.
The most beautiful part is that everything is FREE.
I'm the admin, just ask if there's anything.
Knowledge is the Key.
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497
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Thank you very much! And don't worry I wasn't planning on buying any of that SubZero crap.
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BaiHu
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Gold Refining
Please be advised that gold chlorides tend to be volatile!
It is much easier to use potassium cyanide with oxygen bubbled through the solution (or air) to dissolve the gold.
Next recover by electroplating or cementing out with zinc/aluminum dust.
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Arthur Dent
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Maybe KCN is efficient for that purpose but I would never want to work with that stuff, even with a professional fume hood and a gas mask!!!
The Aqua regia / Sodium metabisulfite method might involve strong and corrosive acids, but it's a hell of a lot safer and the yield is quite good. I
would never recommend a hobbyist chemist to work with cyanide to reclaim gold. This process better be left to the industrial mining industry.
Robert
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