Dissolve lead and tin only!

[jaun]

A refiner told me he uses sodium hydroxide (lye) and hydrogen peroxide to dissolve lead and tin only.

Does any one know about this? GSP, Lou, Steve, Harold
Or is he taking me for a ride?

He also spoke about using sulphuric acid and hydrogen peroxide to dissolve base metal????????

If lye and peroxide dissolve lead and tin, that would make things much easier!

 

[Lou]

No, he's serious.

Base with additions of peroxide is effective, giving you plumbate anion.

 

[semi-lucid]

Lou

Is it possible to then recover the tin and lead from the sodium hydroxide? Is this practical?

J

 

[Lou]

Yes, it can be done. Easiest to just precipitate as the hydrous oxide, and calcine with carbon. That ought to give you lead with tin floating on top. Just guessing here!

 

[Buzz]

In respect to the Lye and Peroxide solution
What would be a good ratio mix?

Regards
Buzz

 

[jaun]

He told me you add the peroxide slowly to the lye solution until all the lead is dissolved, I guess the same as hcl-cl where you ad the bleach little by little.

The stronger the peroxide the better.
We’ll have to experiment and see what ratio works best.

I don’t know if there is any danger in this process, so please be careful. 8)

 

[jeneje]

Hello all, I know this is a very old post, but I am having prolbems with lead and tin in my solutions. I have tryed all the standard ways but still come up with lead and tin. Can the senior members here comment on this process and maybe give some insite on the dangers and correct amounts to use.

Thanks
Ken

 

[machiavelli976]

Hello all, I know this is a very old post, but I am having prolbems with lead and tin in my solutions. I have tryed all the standard ways but still come up with lead and tin. Can the senior members here comment on this process and maybe give some insite on the dangers and correct amounts to use.

Thanks
Ken

Hi there !
If I am somehow in a hurry and I have to use nitric acid for digestion , my best catch is to use a stainless steel basket , hanged about one inch above the bottom of the beaker.
This way the SnO2 and fine lead drops leaving the bulk of pins (or whatever else) pretty clean for perpetual digestion.
The net i use for the basket have about 0.3 mm holes and some fine gold is passing thru obviously .
After digestion , only a slight rinsing above the same beaker would give you the gold clean enough to be dissolved further in AR.
The method is good for thick plating mostly. The light yellow pins will give to you very fine gold , easy to escape from the net.
The recovering of the fallen gold is another story and I'm still experimenting .You should try a boiling in HCl , but not before a good rinsing with tap water.

 

[amosfella]

I'm guessing the sodium hydroxide is mixed with water first...

 

[samuel-a]

I'm guessing the sodium hydroxide is mixed with water first...

sure.
This is your catalyst.

a solution of 50% NaOH with small addition of 30% H2O2 really works fast.
Stay safe, this is the most important thing.

 

[eeTHr]

I wonder if someone could use the standard grocery store 3% peroxide, if he didn't use water, but just the peroxide, with it's 97% water, to make the lye solution?

 

[wct0415]

So in the case of sterling silver knives where the stainless steel blade have been soldered in place, removing the blade with heat to melt the solder and allow the blade to fall out and dissolve the tin/lead with a solution of 50% NaOH with small addition of 30% H2O2. Will this solution affect the silver in any way or can the sterling be processed with 50/50 nitric and H2O. I think that I read in Hoke's book that HCL with H2O can be used to dissolve lead into a salt. Sounds like 50% NaOH with small addition of 30% H2O2 could be used to remove both the tin and lead. Any advise as to a better method would be greatly appreciated. Still trying to learn before jumping in with both feet.

 

[solar_plasma]

Those knives are often filled with sand and bee wax. This should be removed first, since bee wax in conc. NaOH especially if warm will make soap after some time. I never got soap from waxes, when I intended to, but shaving soap as an example is made of stearin acid (candles).

 

[Evan2468WDWA]

I was doing a Google search on C. M. HOKE and I found something related to this topic.

http://books.google.com/books?id=oKLmAAAAMAAJ&pg=PA372&dq=C.+M.+HOKE&hl=en&sa=X&ei=owvDU9uYE8XUiwLpkoHoAQ&ved=0CCwQ6AEwAw#v=onepage&q=C.%20M.%20HOKE&f=false

Apparently if you heat up the caustic you don't need hydrogen peroxide.

 

[necromancer]

I was doing a Google search on C. M. HOKE and I found something related to this topic.

http://books.google.com/books?id=oKLmAAAAMAAJ&pg=PA372&dq=C.+M.+HOKE&hl=en&sa=X&ei=owvDU9uYE8XUiwLpkoHoAQ&ved=0CCwQ6AEwAw#v=onepage&q=C.%20M.%20HOKE&f=false

Apparently if you heat up the caustic you don't need hydrogen peroxide.

there are dangers with hot caustic as with hot sulfuric.
it will eat organic matter away fast (skin is organic) best to try other methods or use all necessary personal safety gear.

a quote from Geo:

""Use some calcium hydroxide. It will convert the tin oxide to a hydroxide which is soluble in water. After mixing in the Ca(OH)2 and giving enough time for the conversion (30 minutes or longer) the tin will dissolve in water and can be rinsed out.""

""You can buy calcium hydroxide at most grocery stores. It's called "pickling lime".""

not sure if this will dissolve the lead too ?

EDIT: spelling/grammar.

 

[solar_plasma]

Link please.

This seems to be completely teared out of its context, since this is about tin oxide (which of them?) and not tin. Though it looks interesting.

 

[Geo]

That's a quote from a different forum about tin oxide (metastannic acid).

 

[necromancer]

this post was brought back to life with a response 3 years to the day after it was needed.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=4998#p213131

i took it as an extension of removing tin / lead from solution.

the OP was in 2009, then bumped in 2011, and again in 2014

did i not remember the definition of "Plumbate" correctly ?
and does my quote of geo's method conflict with something ? i did give credit where credit is due !!

 

[solar_plasma]

No, it's just that this is about tin oxides and not metallic tin. So it can't be used to dissolve metallic tin from boards.

Nevertheless, this method is interesting in other contexts. Thanks for mentioning it.

 

[necromancer]

the real thanks goes to geo

not sure how many tin coated / soldered boards you have but a hot sand bed works to get samples off the boards