Sodium Bisulfite or Sodium Metabisulfite

[Anonymous]

Hi All,

Great forum, I have learned a lot. I have a question about precipitation of Gold Chloride from Aqua Regia. It seem that people on this forum use Sodium Metabisulfite (Na2S2O5), whereas other sources on the internet (see links below) say to use Sodium Bisulfite (NaHSO3). Any thoughts?

Regards, Slag


http://www.e-goldprospecting.com/html/small_scale_gold_refining_by_z.html
http://www.ganoksin.com/borisat/nenam/ajm-roads-2-recovery.htm

 

[goldsilverpro]

I've never used sodium bisulfite. I have used sodium metabisulfite. My preference is sodium sulfite. They all smell badly of sulfur dioxide in use, but the sodium sulfite seems to smell the least . This may be a subjective judgment, though.

I started out with sodium sulfite and learned how to use it. I get consistently pure gold from it. It's commonly used to process photographs and I buy the photo grade, which is fairly inexpensive but quite pure. The Kodak brand is available in some camera stores in 1# packages. The last time I bought it, it ran about $5. It's much, much cheaper in 50# bags. The photo grade bag brand I used to buy was Stauffer (may not be spelled right). You can buy it from most chemical suppliers.

 

[Harold_V]

Don't lose sight of the fact that it is the SO2 that does the precipitation.

If you've busy enough with refining that you can justify the investment, a cylinder of SO2 works perfectly well, and doesn't increase the volume of your solutions. That can be an issue when you refine large amounts at one time.

Harold

 

[goldsilverpro]

I agree, Harold. I've used it a lot and it works great but, I just never liked having it around. It's too poisonous at full strength. All the big guys use it, though.

 

[AuMINIMayhem]

What about "Iron out".. you can get it at pretty much any Walmart or grocery store.. it contains Sodium Metabisulfite and Sodium Hydrosulfite..

I just happen to have some.. wondering if it's useful for anything other than cleaning rust stains from my toilet ..

 

[lazersteve]

I would be very leary of adding products with other ingredients into the mix.

 

[AuMINIMayhem]

yeah.. I figured as much.. see? that's why I'm glad I got people I can ask rather than just trying stuff out with wreckless abandon.. :lol: