# Sodium Bisulfite vs Sodium MetaBisulfite



## kadriver

Hello all, and thanks for your kind inputs. I have a couple of questions.

I have found that Sodium Bisulfite is much more expensive, comes in liquid for, and is kind of hard to get.

1) can I use Sodium MetaBisulfite for dropping gold out of solution?

2) Is there an advantage to using Sodium Bisulfite over Sodium MetaBisulfite?

3) What is the main difference between the two chemicals with respect to gold refining?

4) can liquid Sodium Bisulfite be used to precipitate gold out of solution?

5) Is ther a source of supply for powdered or crystaline Sodium Bisulfite that someone can suggest? I live in the Southeastern United States - South Carolina.

This is a GREAT forum - you guys are very helpful!

Thanks to all who reply - KLS (kadriver)


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## philddreamer

Hi KLS!
1) can I use Sodium MetaBisulfite for dropping gold out of solution?
Yes, you can drop gold with SMB. 

2) Is there an advantage to using Sodium Bisulfite over Sodium MetaBisulfite?
In essence it's the same.

3) What is the main difference between the two chemicals with respect to gold refining?
They're actually different chemicals. Sodium bisulphite is NaHSO3, and Sodium metabisulphite is Na2S2O5. Both are available in powder form, and incidentally have the foodstuff additive numbers of E222, and E223 respectively.
However, as soon as you dissolve Sodium metabisulphite in water it becomes Sodium bisulphite. The addition product of Na2S2O5 + H2O is 2(NaHSO3).
As you may see, there's a difference in the molecular weights of the bisulphite and metabisulphite. Anhydrous Sodium metabisulphite has a molecular weight of 190 to the bisulphite's 104, but the metabisulphite will form two molecules of bisulphite with the addition of one molecule of water. Therefore 19 gms of anhydrous metabisulphite is equivalent to 20.8 gms of pure bisulphite.
Since pure Sodium bisulphite is almost impossible to obtain, it's easier and cheaper to substitute 91.3% of the weight of bisulphite with metabisulphite. 

-- Pete Andrews ([email protected]), March 11, 20

4) can liquid Sodium Bisulfite be used to precipitate gold out of solution?
As far as know... yes.

5) Is ther a source of supply for powdered or crystaline Sodium Bisulfite that someone can suggest? I live in the Southeastern United States - South Carolina.
I'm sure. Home Depot for one. Its called Stump out, by Bonide. Any Brewery supply store, since SMB is a preservative used in beer & wine

Yes, SMB is cheaper, ussually 4 to 5 us dollars/#.
There're many posts on the subject that elaborate & share more precise information, take some time & check them out, so you stay safe & minimize problems.

May you have a golden day!!! 8) 

Phil


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## kadriver

Fantastic - This is exactly what I needed to know.

Thank you for reponding!
KLS


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## syazwan.salleh

Hi all.

I'm Syazwan from Malaysia. I'm currently using SMB's and Copper Sulphate to reduce cyanides content in our wastewater (INCO process). 

My question; 

Sodium Sulphite is used for removing the dissoved oxygen from cyanide solution before zinc precipitaion(Merril-Crowe). Can SMB's do the same job ?
Is it applicable for precipitation of gold in both gold cyanide solutions or gold chloride solutions ?

Thanks.


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## Lino1406

1. SMB will do whatever sodium sulphite does
2. Gold chloride is a strong oxidizer while gold cyanide, in fact
gold potassium cyanide, is not. So to precipitate gold from it
use zinc or aluminum


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## carcrossguy

I bought 250 grams of metabisulfite for $1.79. Seemed good price to me.

brothers too wine makers
101a 20795 langley bypass
langly bc Canada


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## dmc50

Hello I have been trying to get the gold to drop from the aqua regia acid for days now using Sodium MetaBisulfite it will not drop I have ended up with a big bucket of mixed clear and half a bucket of thick cloudy mix on the bottom,can anybody help me please,I do not want to waist any more gold scrap,Cheer's Darrin from New Zealand.


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## Lino1406

The question is too complex. Please describe in detail processes and quantities of materials and results, from the start


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## goldsilverpro

dmc50 said:


> Hello I have been trying to get the gold to drop from the aqua regia acid for days now using Sodium MetaBisulfite it will not drop I have ended up with a big bucket of mixed clear and half a bucket of thick cloudy mix on the bottom,can anybody help me please,I do not want to waist any more gold scrap,Cheer's Darrin from New Zealand.


Either there was no gold in there to start with or there's a lot of free nitric acid in there. Have you tested the solution for gold using stannous chloride? Can you explain in detail what you've done to this point. What type of material? How much of that material? How did you process it? How much nitric did you use? Etc., etc.


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## anachronism

The question I would ask is this. What physically happens when you add a small amount of SMB to the solution now? What do you see exactly? 

Jon


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