# Na2S2O3 as a gold precipitant?



## lowg (Apr 2, 2011)

Has anyone tried to precipitate gold from AuCl3 using Na2S2O3, instead of using SMB (Na2S2O5)?


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## Irons (Apr 2, 2011)

If they have, they probably won't admit it. :mrgreen: 


Sodium thiosulfate is one component of an alternative lixiviant to cyanide for extraction of gold.[3] It forms a strong complex with gold(I) ions, [Au(S2O3)2]3-. The advantage of this approach is that thiosulfate is essentially non-toxic and that ore types that are refractory to gold cyanidation (e.g. carbonaceous or Carlin type ores) can be leached by thiosulfate. Some problems with this alternative process include the high consumption of thiosulfate, and the lack of a suitable recovery technique, since [Au(S2O3)2]3- does not adsorb to activated carbon, which is the standard technique used in gold cyanidation to separate the gold complex from the ore slurry.

http://en.wikipedia.org/wiki/Sodium_thiosulfate


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## lowg (Apr 2, 2011)

Irons said:


> If they have, they probably won't admit it. :mrgreen:
> 
> 
> Sodium thiosulfate is one component of an alternative lixiviant to cyanide for extraction of gold.[3] It forms a strong complex with gold(I) ions, [Au(S2O3)2]3-. The advantage of this approach is that thiosulfate is essentially non-toxic and that ore types that are refractory to gold cyanidation (e.g. carbonaceous or Carlin type ores) can be leached by thiosulfate. Some problems with this alternative process include the high consumption of thiosulfate, and the lack of a suitable recovery technique, since [Au(S2O3)2]3- does not adsorb to activated carbon, which is the standard technique used in gold cyanidation to separate the gold complex from the ore slurry.
> ...



Since I had problems getting SMB, I tried this stuff that I got from some communist lab. that is down for about 45 years. :lol:

Nice looking AuCl3, when I added Na2S2O3 precipitated gold into brown form, then turned in red/orange, then the whole solution turned red/orange, when I filtered it became brown again, then dried - and it became solid as rock. And very hardly dissolved in AR.

I hope I'll get some SMB tomorrow 

Thank you very much for your reply!


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## Irons (Apr 2, 2011)

SO2 gas will work as well. If you can find some sulfur, burning it will produce SO2. Bubbling it into the solution of AuCl3 will precipitate the Au.

It's not the best way to go, but if you're in a situation where chemicals are difficult to acquire, it will do the job.

You can make SMB by bubbling SO2 gas into Sodium Hydroxide solution.


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## dtectr (Apr 3, 2011)

On lazersteve's website read the document/patent (sorry I don't remember which it is  ) on sulforous acid. I believe, at 2 a.m. :lol: that its a process for producing SO2 gas for precipitation. After I get some sleep, I'll recheck & edit this, if necessary.


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## butcher (Apr 3, 2011)

Ferrous sulfate will precipitate gold, you can make it with 10% sulfuric acid and pure soft iron (old transformer laminate cut to pieces, little heat or time.


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## lowg (Apr 4, 2011)

dtectr said:


> On lazersteve's website read the document/patent (sorry I don't remember which it is  ) on sulforous acid. I believe, at 2 a.m. :lol: that its a process for producing SO2 gas for precipitation. After I get some sleep, I'll recheck & edit this, if necessary.




Thank you! It is ok by now.


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## lowg (Apr 4, 2011)

Well.. Today I bought Na2S2O5. 
And the sales-guy (some old chemist professor) offered me to try Na2S2O7. for 2$, 1kg and I took it.  

Do you think I am being ripped off? 8) 
If so
Maybe I could find a good use for it. OR maybe I am just totally ripped off.. :roll:


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## Anonymous (Apr 4, 2011)

lowg said:


> Well.. Today I bought Na2S2O5


Straight SMB,Good Job.How much did you pay?


lowg said:


> And the sales-guy (some old chemist professor) offered me to try Na2S2O7. for 2$, 1kg and I took it


I do not suggest using it.Sodium pyrosulfate tends to drag down contaminants upon precipitation,giving you "dirty"gold powder that should be redisolved.


lowg said:


> Maybe I could find a good use for it.


Almost the same as Super Iron Out.


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## lowg (Apr 4, 2011)

mic said:


> lowg said:
> 
> 
> > Well.. Today I bought Na2S2O5
> ...




Thank you , appreciate your answer! But I didn't find anything on your term 'Super Iron Out'. What did you mean?

I bought it 6$ for 1kg. But for 35kg quantity price was about 80 cents/kg and for 5kg qt. it was 2.50$ per kg


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## Anonymous (Apr 4, 2011)

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=6763&p=68712&hilit=super+iron+out#p65145


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## lowg (Apr 4, 2011)

mic said:


> http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=6763&p=68712&hilit=super+iron+out#p65145



Thank you


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