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Na2S2O5 is smb. Hydrosulfite, Na2S2O4 if formed, reduces gold in alkaline environment if at all formed. (To produce it zinc is needed)

You didn't understand my topic correctly :)

Na2S2O4 is sodium hypodisulfite. It cannot be formed here.

Hydrosulfite has this formula: NaHSO3. In English, it is also called: Sodium bisulfite.
Slightly different meaning, mea culpa :)

Three ways of reactions :
(a)SO2-inducted Au reduction, (b)forming hydrosulfite (bisulfite), and (c) direct SMB (Na2S2O5 + HCl) reaction, NOT with hydrosulfite. I didn't call SMB as "hydrosulfite". I thought that Na2S2O5 is obviously SMB for readers.

All these reactions go at different speeds that's why can shift acidity unpredictably fast.
 
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You didn't understand my topic correctly :)

Na2S2O4 is sodium hypodisulfite. It cannot be formed here.

Hydrosulfite has this formula: NaHSO3. In English, it is also called: Sodium bisulfite.
Slightly different meaning, mea culpa :)

Three ways of reactions :
(a)SO2-inducted Au reduction, (b)forming hydrosulfite (bisulfite), and (c) direct SMB (Na2S2O5 + HCl) reaction, NOT with hydrosulfite. I didn't call SMB as "hydrosulfite". I thought that Na2S2O5 is obviously SMB for readers.

All these reactions go at different speeds that's why can shift acidity unpredictably fast.
Ok thanks for clarifying. My misunderstanding because more accepted names for hypodisulfite, are hydrosulfite, dithionite
 
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In Ukrainian/Russian languages, chemists often use the prefix "hydro" when OH(-) is present in the formula.
For example:

Na2SO4 - sodium sulfate, but NaHSO4 - sodium hydrosulfate,
Na2CO3 - sodium carbonate, but NaHCO3 - sodium hydrocarbonate,
Na2SO3 - sodium sulfite, but NaHSO3 - sodium hydrosulfite,

So I will try to use just international formulas to avoid misunderstanding :)
 
I mistakenly added SMB thinking I was adding Sulfamic. 150ml of Aqua regia. “Maybe 1.8g” of eWaste gold bond wires dissolved. 1.8g was my guess before beginning to process. Went through all the accepted standard processes. I’d boiled in HCl for two weeks (multiple acid changes) to clean out as much base metal as possible. Was going beautifully until my goof. I am not sure how I could goof so badly. I added about 3 tablespoons of SMB before I gave up on it because the results I was seeing didn’t meet my expectations (thinking I was adding Sulfamic). I added my water (doubled volume to 300ml) and the volume of fluid in the beaker instantly became a cloudy grey poupon mustard color, then began to form a gradient like pattern exactly like when the normal black gold drop happens and the water becomes clear like a curtain being lowered. Exact same thing here except the curtain was grey poupon colored. But I goofed so I found this thread and Ultrax comments. Terrified am I. Before and after stannous testing performed, pictures attached. What do I have here? Is it a gold drop? I’ve never had a gold drop this color.

Edit— meant to add also. Since I thought this was the Sulfamic stage of processing I’d not filtered yet. So there’s die bits mixed with the substrate.
 

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I don't think that your situation is the same as the OP.
Smb will use up all of the free nitric unless you have way over used your nitric.
I'm thinking that you should be able to pour off the liquid and wash the excess smb out with hot water.
It will take several washings to get it all out .

Then you can dissolve your gold
Again just enough nitric acid to dissolve, filter your solution until it is clear and precipitate your gold with smb .
 
I hope that’s the case Golddigger76. I was reacting to Ultrax very detailed explanation of what happens … “If SMB is over-poured (without pre-hydrolysis)…. “. Which is exactly how it went down for me since I thought I was pouring Sulfamic.
 
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