Added SMB and instead of brown I got grey mud. Please help

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MattttyD

Member
Joined
Aug 7, 2016
Messages
7
So I've used this same material before and it yielded gold before. I used the same stuff from the same batch of material only substantially more and when I added SMB I got this grey mud instead of the brown like before. I tried melting it and just got some hard black crap. Any thoughts or how to correct it?
 
You will have to give quite a lot more detail to get a reasonable answer. What is the source material, what did you dissolve it in, how did you get rid of the excess nitric / bleach / whatever. etc.
 
I had a grey mud looking stuff once and when I tried to melt it. It turned black crust. The only thing was I wasn't trying to recover gold. It was keyboard mylars and the grayish mud was silver chloride it turned into a black crust when I tried to melt it. Then I switched to a hotter torch, and got a nice little piece of silver.
Hope these guys can help you it sucks to loose gold. Always read as much as you can, cross reference everything and weed out the trash. These guys here a really good and helping bag it up and get it on the curb for pick up. (Trash that is)
 
Sounds like he had a little bit of gold and just kept adding more smb thinking more would drop. If you saturate the solution with smb it will produce white crystals which when mixed with small amounts of gold will look grey. He tried to melt it and that's where the black crust came from. Just a guess of course!
 
kernels said:
You will have to give quite a lot more detail to get a reasonable answer. What is the source material, what did you dissolve it in, how did you get rid of the excess nitric / bleach / whatever. etc.

So I used gold commutator material from a defense company that they were throwing away. It's something that I can't find or look up. I used Aqua Regia to dissolve the material and urea to neutralize the acids. The only thing I did differently was filter the urea out this time. Then added smb. When I was trying to melt this grey mud parts of it were turning blue which I've never seen either. I crushed some of this hard black crust and there was some color but looked more like copper or rose goldish.
 
Palladium said:
Sounds like he had a little bit of gold and just kept adding more smb thinking more would drop. If you saturate the solution with smb it will produce white crystals which when mixed with small amounts of gold will look grey. He tried to melt it and that's where the black crust came from. Just a guess of course!

Yeah that seems likely. Do you think I could attempt to dissolve everything again in AR To recover the gold?
 
Id try rinsing out the white crystals with hot water washes first.

Then ammonia (if AgCl)
-then hcl the ammonia

Then see what you have left
 
You could wash it out, but were it me i would wash it and ar it again. Use as little solution as possible so it's concentrated so you get a good particle size when you drop it and it will be easier to handle. Plus doing it over again at this stage is easy and gives you more experience at where you went wrong. My first oz of gold i bet i dissolved and precipitated it at least a dozen times!
 
The white crystals that form from an over addition of metabisulfite are copper (1) chloride. Cuprous chloride. The white crystals are not soluble in water but are very soluble in warm hydrochloric acid.

When dropping gold from solutions with metabisulfite, there is a definite color change when you have dropped all of the gold. With experience you can tell when it is done by just looking at it as you add the SMB. However always test to be sure. You just over did it.
 

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