# Precipitating Gold



## DionSukhram6 (Jan 6, 2017)

I'm pretty new to gold refining, so I was practicing by trying to dissolve some gold leaf in a mixture of HCl and hydrogen peroxide. I was able to successfully do so and then tried to precipitate it. I dissolved some SMB in water and added it but the solution just turned a lighter yellow and there was no precipitate, so I was wondering why this might happen. Thank you!


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## Topher_osAUrus (Jan 6, 2017)

Hello, welcome yo the forum.

Did you do a stannous test?

The smb is sodium metabisulfite, do you have that or sodium metabisulfAte?
If the former, woft a little of its odor to your nose. Does it smell good? Then its gone bad, if it smells terrible, then its good still.

If you test with stannous after adding smb, the SO2 will give a false positive if you overdosed it, giving brownish result on the test.


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## patnor1011 (Jan 7, 2017)

Was that really a gold leaf? Not just content of one of those ebay vials?


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## nickvc (Jan 7, 2017)

As Patnor stated there is little real gold leaf around most is just brass, the other possibility is you still have excess oxidiser so the gold will not precipitate until you have neutralised it.


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## FrugalRefiner (Jan 7, 2017)

You didn't mention how much gold leaf you dissolved. Since this was practice, I'm guessing you only dissolved a sheet / few sheets. Gold leaf is extraordinary thin. A single ounce of gold can be beaten into 100 square feet of leaf. So if you only dissolved a small amount, and assuming it was true gold leaf, it may be difficult to see the precipitate.

Give us an idea of how much leaf you dissolved and we can give you an idea of what you might expect.

Dave


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## lanfear (Jan 26, 2017)

If that was gold leaf you bougt in vials, there is no gold to drop. I had 5 vials of gold leaf i bougt when I first started to get interested in refining. I figured out right after that it was probably fake, and did not refine it.
I found them again a year ago, and to confirm my suspicion i dropped it all in nitric. The result was pooof!
The gold leaf was gone..

Jon


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## Hunter2700 (Feb 18, 2017)

I added the smb to the solution and it turned blue instantly... What do I do??


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## FrugalRefiner (Feb 18, 2017)

You can start by answering some of the questions members asked you. If you don't, any answers you might receive are just guesses.

Dave


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## g_axelsson (Feb 18, 2017)

Hunter2700 said:


> I added the smb to the solution and it turned blue instantly... What do I do??


Based on the detailed information you gave... something wrong. :wink: 

Göran


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## denim (Feb 18, 2017)

Why did you use HCL and H2O2? Why not one of the more tried and true methods of HCL and bleach, or HCL and small increments of oxidizer like sodium nitrate? I have never intentionally dissolved gold using H2O2. Have I missed something?


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## FrugalRefiner (Feb 18, 2017)

While slower than AR, poor man's AR, or HCl/bleach, HCl/H2O2 can work well on finely divided gold. It's advantage is that the only thing left from the H2O2 after oxidizing the gold is water. 

Dave


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## denim (Feb 19, 2017)

Thanks Dave. I did not know that.


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## prospector_pete (May 4, 2020)

DionSukhram6 said:


> I'm pretty new to gold refining, so I was practicing by trying to dissolve some gold leaf in a mixture of HCl and hydrogen peroxide. I was able to successfully do so and then tried to precipitate it. I dissolved some SMB in water and added it but the solution just turned a lighter yellow and there was no precipitate, so I was wondering why this might happen. Thank you!



how could you have disolved gold in AP ?


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## FrugalRefiner (May 4, 2020)

Gold will dissolve in HCl as long as there is an oxidizer present. In AR, the oxidizer is nitric acid. In AP, the oxidizer is the peroxide. In HCl/bleach, the oxidizer is bleach. Even HCl alone will very slowly dissolve gold from the oxygen from the air. Study the forum. All of this information is here.

Dave


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## Golddigger1214 (Sep 16, 2020)

Ok so question. If one took multiple forms of e scrap and put them all in separate containers with hcl/ h202 mixture to devolve bm how would one then get the gold out of said solution? Here's some facts so as to better help answer this question

1. 2:1ratio hcl/h202 used
2. Escrap = mixed pins, fingers, incinerated ic chips crushed to fine powder with magnetic parts removed 
3. Parts have been in solution for over a week in the heat covered with coffee filter . 

Pins were filtered, rinsed then put back into solution have been in there for 3 days.


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## Martijn (Sep 20, 2020)

Did you put the pins and fingers in a strainer bucket inside the container?
Then just lift the solid parts and wash them in a separate wash bucket, by moving the strainer bucket up and down. You can spray the last bits of with a spray bottle.
Filter the solution and reuse. 
Then filter the washwater in the same filter. 
Your gold is in the filter. Together with small plastic parts and other rubbish.


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## Golddigger1214 (Sep 20, 2020)

I did not put them in a strainer. Also, how do I separate the gold from the plastic parts and rubbish? And how do I get it off the filter once its filtered?


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## Martijn (Sep 23, 2020)

Just put the filter with the plastic in AR or HCL with bleach. You will filter the gold chloride solution after dissolving, thats where you separate the gold (and traces of copper and possibly PGM' s that went into solution) from all the fine trash you can't pick out.


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## Martijn (Sep 23, 2020)

After you filtered the big plasic out with a strainer.


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## Golddigger1214 (Sep 24, 2020)

Ok so once I filter the big particles out and then run the solution through another filter, do I take the filtered solution and do anything with it? I'm asking because I can see that some of the gold is not filtering out of the solution its getting through the filter because its so fine.


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## Martijn (Sep 27, 2020)

A paper (coffee)filter will not let any gold pass through imo. 
The fitered solution goes back in the container for some more plated material. Don' t add anymore H2O2. 

Or it goes in a storage container for later use. 

If you want to get rid of it treat it as waste. 
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=47&t=1300
There should be no visible gold after filtration through a filter. Even some fine precipitated gold dust should be captured by the filter. Something went wrong there.
Double the filter or try other filters? 
You may have not rinsed all the small flakes out of the first container and poured the filtered solution back in?

Martijn.


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## Golddigger1214 (Sep 27, 2020)

I figured out what the issue was. I was using an old dress shirt of my husband's and it wasn't catching the fine God dust. Coffee filters rip too easily so I thought I'd try the shirt and see how it held up, holds up just fine, but let's the gold dust through. Guess its time to invest in some actual filters lol.


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## Martijn (Sep 27, 2020)

I use these types: 


The chemical grade filter on the bottom is from the box and are hardly ever used. 
The coffee filters work fine.
I use the big ones for hydroxides in waste treatment.


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## philddreamer (Sep 27, 2020)

If and when using coffee filters, the brown ones are preferred... the pores are smaller and tighter, thus keeping the fine gold particles from filtering thru!

Take care!

Phil


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## Golddigger1214 (Sep 28, 2020)

Thanks Phil! The image is very much appreciated. I was using the bleached white coffee filters originally. I will try the brown ones.


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