Precipitating Gold

[DionSukhram6]

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!

 

[Topher_osAUrus]

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.

 

[patnor1011]

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

 

[nickvc]

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.

 

[FrugalRefiner]

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

 

[lanfear]

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

 

[Hunter2700]

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

 

[FrugalRefiner]

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

 

[g_axelsson]

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

 

[denim]

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?

 

[FrugalRefiner]

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

 

[denim]

Thanks Dave. I did not know that.

 

[prospector_pete]

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 ?

 

[FrugalRefiner]

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

 

[Golddigger1214]

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.

 

[Martijn]

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.

 

[Golddigger1214]

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?

 

[Martijn]

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.

 

[Martijn]

After you filtered the big plasic out with a strainer.

 

[Golddigger1214]

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.