# Gold precipitation...



## Ben321 (Apr 30, 2018)

Hello again everybody.

Here's my quandary. I have gold foils, from fingers and circuit boards, they were 1st ran through AP solution to remove base metals and loosen the remaining foils from the boards. I filtered them out of the AP. Rinsed the filters in HCL, Now I have them in HCL and Bleach to dissolve the foils. The question is I have some "Rust Out" which contains Sodium Hydrosulfite and Sodium Metabisulfite. Can I use it to precipitate the gold from the HCL/ Bleach solution or will it mess it up being as there is Hydrosulfite in the mix???


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## FrugalRefiner (Apr 30, 2018)

Since you're at the point of reducing your gold out of solution, do you really want to add more possible contaminants? SMB is cheap. Stump remover from the hardware store or sanitizer from the home brew shop will cost less than $10.00. I cut corners on a lot of things, but rarely on the last step.

Dave


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## Ben321 (Apr 30, 2018)

I guess what i'm asking is Why would the Hydrosulfite mess up this reaction??


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## g_axelsson (Apr 30, 2018)

I have no idea what hydrosulfite would do with the different metals in solution. Maybe nothing, maybe reacting with something that falls out of solution and contaminate your gold.

I bought a kilo of SMB ten years ago and I still have some left after precipitating more than 200 grams of gold. I spent about $20 including postage so I'm paying less than 10 cents per gram of gold and get a clean product. Now I have started to use copperas too (making it myself) and that is even cheaper.

I don't think you will get an answer on your question since no one is using "Rust out", the alternatives are cheap, working well and is easy to get, hard to beat that.

I understand that you might be impatient to get the gold out or maybe you're trying to save a dollar on using stuff you already have at home. But is it really worth the risk of messing up this close to the end? And by the way, what is the SMB concentration in "Rust out"? Using powder it's easy to get the correct amount and not precipitate a lot of copper chloride.

Göran


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## Shark (Apr 30, 2018)

Bonide Stump Out from Home Depot is around $8 a pound. I bought two pounds almost 5 years ago and only opened the second one because I got to lazy to dig it out from the bottom with a short spoon. If I wanted to cut a corner a bit better instead of using an unknown chemical I would have bought a longer spoon.


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## Ben321 (Apr 30, 2018)

Göran its 98% SMB 2% Hydrosulfite. 
And Guys, Yes we would and do cut corners when and where needed. It was posed as more of a question of curiosity than a "cutting corners" question. I was using the stuff to take rust off of some old tools my Granddad had and got to reading the ingredients, and thought I'd possibly use it, but I'd better ask the experts first. Thank you all for your insight and knowledge, I'll be using straight SMB in the final step. Thank you all.


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## Lino1406 (Apr 30, 2018)

No problem with 2% HS, as it reduces stronglier than bisulfite (HS is made by Zn reduction of sulphite)


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## Topher_osAUrus (May 1, 2018)

Shark said:


> Bonide Stump Out from Home Depot is around $8 a pound. I bought two pounds almost 5 years ago and only opened the second one because I got to lazy to dig it out from the bottom with a short spoon. If I wanted to cut a corner a bit better instead of using an unknown chemical I would have bought a longer spoon.



Just add water to the first bottle and use it with a pipette. Works wonderfully. (Hate them short spoons!) :lol:


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## Shark (May 1, 2018)

Lino1406 said:


> No problem with 2% HS, as it reduces stronglier than bisulfite (HS is made by Zn reduction of sulphite)



Would this still produce that awful smell that SMB does?


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## snoman701 (May 1, 2018)

Lino1406 said:


> No problem with 2% HS, as it reduces stronglier than bisulfite (HS is made by Zn reduction of sulphite)



Ok, first question...is stronglier accepted English over yonder? I am entirely serious, I'm intrigued by word use.

Second, any chance of thiosulphate production, that could theoretically keep gold in solution...although I'm not sure at that low of a pH? 



Shark said:


> Would this still produce that awful smell that SMB does?



Sulfur Dioxide?


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## Lino1406 (May 1, 2018)

Snowman yes, the chance of thiosulphate, hence sulfur is almost meaningless at this low concentration. Stonglier - if it is understood then it is OK (both views in my opinion)


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## Jordan1 (May 7, 2018)

Which is the cleanest way to precipitate gold ?

Copperas , smb or so2 ?

Please explain why and how each precipitate reacts differently?


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## FrugalRefiner (May 7, 2018)

Jordan1 said:


> Which is the cleanest way to precipitate gold ?
> 
> Copperas , smb or so2 ?
> 
> Please explain why and how each precipitate reacts differently?


Is this a quiz? Is there a prize if I get the answer right?

Sorry, I know that was a pretty snarky response, but asking the question leads me to believe you need to do some more studying of your own. Which precipitant is best depends on the situation, e.g., what metals might be in solution, in what quantities, etc. SMB produces SO2 in an acidic solution, so the precipitation is similar. 

So there is no, single, right answer. If you want the "cleanest" gold, there are other precipitants that might give you a better result.

Everything is here on the forum, but you'll have to spend some time reading to find it. It's not that we won't help you, but you need to learn enough to formulate a question we can answer.

Dave


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## kernels (May 7, 2018)

Jordan1 said:


> Which is the cleanest way to precipitate gold ?
> 
> Copperas , smb or so2 ?
> 
> Please explain why and how each precipitate reacts differently?



:lol: Great question, transfer $200 in either Bitcoin or Cash to one of the forum elders and they will spell it out for you. Alternatively, study study study, then do small scale experiments, then ask specific questions when you don't get exactly what you expect. If you show the effort that you have put it, you will be amazed by the quality of answers you can get on here.


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