sulfur dioxide

[Anonymous]

Can/would someone tell me the reaction that causes gold to precipate with the sulfur dioxide, I spefically want to know if elemental sulfur is produced along with the gold, or what happens to the sulfur dioxide.

thanks
jim

 

[lazersteve]

Here's a post with some common refining equations:

Refining Equations

Sulfur can be produced by manipulation of the barren solution saturated with SO2 in accordance with reactions outlined in this document:

SO2 Solutions

The one observation that the author made that I would argue with is that the white precipitate observed in the last paragraph on page three is sulfur, I feel it's zinc sulfide.

I have successfully used this overall process to precipitate spent refining solutions using the H2S that is formed in situ.

Be very cautious attempting this type of reaction as H2S gas is deadly and should not be formed unless you are well equipped to deal with it's vapors. H2S initially smells of rotten eggs, but after longer exposure and/or greater concentrations, the smell is not detected due to it's action on the sinus nerve!

The toxicity of H2S is the main reason I have not posted this information in the past. I urge anyone that is not properly equipped to never attempt this reaction.

The sulfides formed are then reacted to produce sulfur as a by product.

It's very interesting to note that hyposulfurous acid affords a route to regenerate sulfites and many other useful reagents 8) .

Be safe everyone and Merry Christmas!

Steve