# piranha and base piranha in refining?.



## HAuCl4 (Sep 28, 2010)

Do any of these have a place in refining precious metals?:

Many different mixture ratios are commonly used, and all are called piranha. A typical mixture is 3:1 concentrated sulfuric acid to 30% hydrogen peroxide solution; other protocols may use a 4:1 or even 7:1 mixture. 

A closely related mixture, sometimes called "base piranha", is a 3:1 mixture of ammonium hydroxide (NH4OH) with hydrogen peroxide. Base piranha is also known under the names of TL1 cleaning and SC1 cleaning and is part of the RCA clean procedure.

http://en.wikipedia.org/wiki/Piranha_solution

What happens if you drop any of these two (not both) on a silver-gold or copper-gold inquart?. On sterling silver?.

At first look, the first one would play as a subtitute for nitric acid, which is hard to come by in some places. Maybe too violent?. Certainly dangerous stuff.


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## texan (Sep 28, 2010)

Like the write up says...it's named Piranha for a reason...about as friendly/easy to work with as Hydrofluoric Acid...

Right now my lab does not even have Nitric.

Texan


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## HAuCl4 (Sep 28, 2010)

texan said:


> Like the write up says...it's named Piranha for a reason...about as friendly/easy to work with as Hydrofluoric Acid...
> 
> Right now my lab does not even have Nitric.
> 
> Texan



Have you used any of the two "preparations" to refine or dissolve inquarts?. I wonder how fast they are, if they work.


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## nickvc (Sep 28, 2010)

HAuCl4 said:


> texan said:
> 
> 
> > Like the write up says...it's named Piranha for a reason...about as friendly/easy to work with as Hydrofluoric Acid...
> ...


Maybe not one for the amateurs to try!
Advice from one of our senior members here is called for I think if it's as nasty as hydrofluoric.


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## HAuCl4 (Sep 28, 2010)

nickvc said:


> HAuCl4 said:
> 
> 
> > texan said:
> ...



Some people have posted videos on using H2O2 with Nitric acid...so it's really not too far fetched to try it with sulfuric...

I haven't tried it, but if I were to try it, I would drip the sulfuric SLOWLY into the mix of metal shot and H2O2 to see what happens. That's for mix1. For mix2 I don't know how I would use it.

I see a nice upside, same as with nitric: No fumes to scrub.


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## lazersteve (Sep 28, 2010)

Here's a previous discussion:

Piranha

Steve


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## Lou (Sep 28, 2010)

No use in anything we do.


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## ChaseDaBase (May 20, 2019)

I'm new to this forum, and to gold recovery in general. I am just doing this more as a hobby and for fun. I just wanted to get a clear answer on what was originally asked in the beginning.

I used a 3:1 ratio 3% hydrogen peroxide and concentrated sulfuric acid mixture to try and liberate gold I had collected from the filter papers it was in. I tested the solution with stannous chloride and it came up looking positive for gold (kind of saw a purple stain). I just want to know if it's even possible for what I did to dissolve gold? And if it can, how do I "drop" the gold?

Any information anyone can give me will help.


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## Lino1406 (May 20, 2019)

To dissolve gold in this environment Cl- ions are needed (e.g. from the filter paper). To drop gold - any dropper. Verify it is gold


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## ChaseDaBase (May 21, 2019)

Lino1406 said:


> To dissolve gold in this environment Cl- ions are needed (e.g. from the filter paper). To drop gold - any dropper. Verify it is gold



The filter papers most likely had hydrochloric acid residue on them. As far as a "dropper" you mean something like sodium metabisulfite?


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## Lino1406 (May 21, 2019)

SMB, Nitrite, copperas, zinc, aluminum, copper, ascorbic acid...


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## ChaseDaBase (May 21, 2019)

Lino1406 said:


> SMB, Nitrite, copperas, zinc, aluminum, copper, ascorbic acid...



Cool. Thanks for the help.


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## g_axelsson (Jun 7, 2019)

Filter papers might also have already dissolved gold chloride in it.
Try to add a drop of stannous on an old filter paper and you will know.

Göran


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