Grey green and white powder with my gold

[timsiggins]

So I had some computer pins that I got on ebay 140 grams of then that I used diluted nitric acid to break them down after I did that a few time, decanting and just saving the power and liquid and then process the pins in fresh solution I got this powders with my gold flakes I have tried to filter it out and that was no go I even try a fine screen that you use for kcups and it could some gold but let the fine flake pass through it.




How do I get rid of the powder, can I use AR and then drop the gold with SMB help please

 

[lanfear]

Did you use distilled water? It could be a mix of AgCl and other things. Have you tried to boil it in distilled water to see if the goop is soluble? It's possible the goop is metastannic acid. Search the forum for metastannic acid.

Jon

 

[timsiggins]

I only used distilled water and I boiled it in nitric and distilled water

 

[Yggdrasil]

If it was not completely free of tin before the nitric was added, it is likely to be metastannic.
That is why it is wise to dissolve tin in HCl first.
And then AP.
If you are taking the Nitric route, either make sure it is completely clean from Tin (Sn) or soak in HCl and then roast before Nitric.
Now you will have to roast and then HCl to remove metastannic acid.

 

[Lino1406]

Removal of SnO2 - by Zn + HCl combined together

 

[Yggdrasil]

I have never heared about that procedure before, Lino.
Learned something new today, so it is a good day

 

[Martijn]

Is that due to reactivity series in an acidic solution? Tin being less reactive than Zinc? basically cementing out the tin?

 

[timsiggins]

How high temp should I roast it for I have my electric smelter that I can control the temp on

 

[timsiggins]

Also I thought to do a distilled water boil on it to clean all the nitric off 1st, that’s a good idea right?

 

[Lino1406]

The zinc reduces insoluble Sn(+4)O2 to soluble Sn(+2)

 

[g_axelsson]

Removal of SnO2 - by Zn + HCl combined together

Do not add HCl unless you want to dissolve the gold too. To wash away the remaining nitrates is just as hard as filtering off gold chloride from the metastannic goop you have here.

If it was my mess I would probably try to incinerate first and then wash it with HCl to get some tin to dissolve and make it easier to filter. Or maybe just dissolve the gold and use a wick filter to get the most of the gold out of solution.

A lot of pins are made from brass or bronze and can contain a lot of different alloying elements. Too late now, but the next time, do a quick test in a test tube to discover problems before you are standing there with a mess.

Göran

 

[timsiggins]

Sorry to ask a noobie question but I there a thread that talk about finding out base metals

 

[timsiggins]

Also if you dissolve the gold with AR is th gold solution going to sit on the bottom because it heavy. I could totally do that and keep texting my solution until it has no gold

 

[Yggdrasil]

??????
This last post do not make sense.
Please elaborate.

 

[timsiggins]

Wow sorry about that was bad English, I was trying to say if I dissolve the gold with AR, then try to wick it. How does that work would the gold on solution be heavy and sit at the bottom


On another note I roasted it twice and used hcl to get the gold clean now I have this. I’m going t try a third roast but I’m thinking this is a lost cause

 

[FrugalRefiner]

Wow sorry about that was bad English, I was trying to say if I dissolve the gold with AR, then try to wick it. How does that work would the gold on solution be heavy and sit at the bottom

Wicking, as Göran suggested, is a way to separate your gold bearing solution from the difficult to filter sludge. Your wick acts in the same way as a syphon. The wick carries the pregnant solution down to a second, lower vessel. Then you can drop the gold. It doesn't have anything to do with the weight of the gold solution sitting at the bottom. That just doesn't happen.

Dave

 

[Yggdrasil]

The AR solution will go out in the wick filter.
This will need extra fluid to get as much gold as possible.
So it will lead to a need of evaporation.
I would roast/incinerate (heat until dull red), this will remove Nitric and NOx.
Then use zinc and HCl as Lino suggested

 

[timsiggins]

How much zinc can I use and is there an easy source for it or should I just order it

 

[Lino1406]

According to SnO2 + Zn+ 4HCl = ZnCl2 + SnCl2 +2H2O
The amount of Zn required is 65.38 g per 150.7 g SnO2. So, each g of SnO2 requires around 0.43g Zn. Use some excess

 

[timsiggins]

So I dissolved it w AR and, tested it with SC, it tested positive then. Dropped it with SMB, I’m going to keep it like this and add it to my next batch. Thanks for all your help guys, I know its not very much it was only 150g of pins and I might have lost some being inexperienced