# How to process AgW Contacts?



## razvanflorin (May 10, 2016)

Hi everybody ! I Would need some help on recovery of silver from AgW Contacts :mrgreen: 

That's my idea:

Nitric Dissolve silver, but not Tungsten so i was thinking to crash them in a ball mill, to make it powder then put it in nitric, wait for dissolving silver, decant and filter the solution then percipitate with HCL/SALT/COPPER. It will work ?

Else i have heared about some processes using HOT HCL + Concentrated H2O2 for dissolving Tungsten, then processes with nitric, What is the better way? Please help me !! :mrgreen:

I apologize if i posted in the wrong section


----------



## Lou (May 10, 2016)

Never tried ball milling them, but I imagine the lower silver Elkonites will fracture ok. That'll make them go faster. They're done when yellow tungstic acid is left behind and/or the pieces can be easily snapped with finger strength alone. Then you can filter the silver nitrate solution, do a quick titration to determine free Ag, add HCl sufficient to precipitate 99 percent of the silver contained as its chloride, filter that, and reduce the silver chloride into silver by tumbling for a few hours with dilute sulfuric acid and clean pure iron. That can then be rinsed with borax and dilute nitre solution and melted into bars. Happy trails 

FYI, peroxide will be decomposed by the silver and tungsten dissolves better in neutral peroxide anyways. Sounds nice on paper but in practice it's a fail.


----------



## razvanflorin (May 11, 2016)

Lou said:


> Never tried ball milling them, but I imagine the lower silver Elkonites will fracture ok. That'll make them go faster. They're done when yellow tungstic acid is left behind and/or the pieces can be easily snapped with finger strength alone. Then you can filter the silver nitrate solution, do a quick titration to determine free Ag, add HCl sufficient to precipitate 99 percent of the silver contained as its chloride, filter that, and reduce the silver chloride into silver by tumbling for a few hours with dilute sulfuric acid and clean pure iron. That can then be rinsed with borax and dilute nitre solution and melted into bars. Happy trails
> 
> FYI, peroxide will be decomposed by the silver and tungsten dissolves better in neutral peroxide anyways. Sounds nice on paper but in practice it's a fail.



Thanks you for the answer,but i didn't understood very well.. 

"They're done when yellow tungstic acid is left behind and/or the pieces can be easily snapped with finger strength alone."
I have just to put them in nitric and wait ? it will works without ball miling or do i have to crush them ? :?:


----------



## nickvc (May 11, 2016)

Cover them in nitric and heat the solution, it's not a quick process but it works, if the reaction stops try a little more nitric and keep adding in small amounts until all reaction stops.
The remaining tungsten will look like it's been hollowed out.


----------



## kurtak (May 11, 2016)

I have never tried ball milling them ether but I don't believe milling will work - at least not well - at best it might break corners & edges off but I don't think it will actually "crush" them into a powder

in order to get ALL the silver out of them you have to literally "boil" them in the nitric acid at a "low" boil 

depending on your batch size AND the size of the point figure 8 -10 hours of boiling in the nitric

without boiling you will not get all the silver out of them - it takes the boiling action (motion) for the acid to work "into" the tungsten matrix & dissolve the silver all the way to the core (center) of the point

If you simply heat the acid - but don't bring it to a boil - it would take days to leach ALL the silver out & even then you likely wont get it all the way to the center

You test to see if you have got all the silver out of them by fishing one (or two) of the larger ones out of the acid & break it in half --- if they break very easy & are black in color all the way to the center they are done --- if they are not done you will see a silvery color in the center &/or they will not break easy

Kurt


----------



## razvanflorin (May 11, 2016)

After i crush them or IT doesn't matter ?


----------



## kurtak (May 11, 2016)

I don't think they will crush --- trying to crush them will be a waste of time (in my opinion)

put them in the acid whole & bring them to a "low" boil - let them boil for about 6 hour & then check to see if all the silver is out (by breaking them as I said) if there is still a silvery color in the center let them boil some more

I will look to see if I have some pictures that shows what they look like when done & when not done --- if I have pictures I will post them later

Kurt


----------



## Lou (May 11, 2016)

razvanflorin said:


> Lou said:
> 
> 
> > Never tried ball milling them, but I imagine the lower silver Elkonites will fracture ok. That'll make them go faster. They're done when yellow tungstic acid is left behind and/or the pieces can be easily snapped with finger strength alone. Then you can filter the silver nitrate solution, do a quick titration to determine free Ag, add HCl sufficient to precipitate 99 percent of the silver contained as its chloride, filter that, and reduce the silver chloride into silver by tumbling for a few hours with dilute sulfuric acid and clean pure iron. That can then be rinsed with borax and dilute nitre solution and melted into bars. Happy trails
> ...



If it's just a yellow powder remaining, you can be sure that you have leached 100 percent of the silver. Even the break test isn't a sure indicator that they're done. 

In case you didn't understand...you can also reuse the nitric acid from this operation many, many times.

Lou


----------



## razvanflorin (May 11, 2016)

Thanks you all, i got it  thanks you very much.


----------



## Topher_osAUrus (May 11, 2016)

razvanflorin said:


> Thanks you all, i got it  thanks you very much.




Lou and Kurt know their stuff!

I had a bunch of silver contacts to do recently from a huge HVAC unit out of my brother-in-laws meat packing plant.

I initially thought they were all just silver (coin silver percentage wise)

but then I found out they were Ag/W (more of them that I would have liked to be)

I ended up boiling(I say boil, but I mean **low simmer**) in nitric (45percent/HNO3 45H2O/10H2O2) for like 4 days... the remainder crushed in my fingertips like I was Hercules smashing his foes.

Do you have any pictures?
I love me some pictures!

Thanks
-topher


----------



## razvanflorin (May 11, 2016)

Thanks Topher 

I have just one more question: 
If i will Boil the acid that contains silver, 
Do i need to make a distillation of the vapours ?
i mean.. it is possible to have loss silver in the vapours of boiling ? :mrgreen: :arrow: 

Thanks you in advance.


----------



## nickvc (May 11, 2016)

razvanflorin said:


> Thanks Topher
> 
> I have just one more question:
> If i will Boil the acid that contains silver,
> ...



Probable and possible but silver has such a low value it's not worth worrying about, if you have a decent scrubbing system you will recover it at some point.


----------



## Topher_osAUrus (May 11, 2016)

nickvc said:


> razvanflorin said:
> 
> 
> > Thanks Topher
> ...



/\ -this

I agree with nick. It most certainly will make your values evaporate (in a sense). But, a good reflux/watch glass should keep loses to a minimum. 

Should you have a filtered fume hood or good scrubber system, you should (eventually) be able to reclaim those values some time down the line.

But,.you should only *slightly* boil them... Just barely simmer. But, periodically check to make sure you still have a bit of red fume (NOx gases) coming off to make sure the acid is still working. -the red fume will be minimal if it is diluted adequately, and if you (also) use H2O2, as it helps keep the NOx gases in solution.

A fresh batch of acid after a day or two will help you to asses progress. And, i assume you would be checking the progress of the contacts by crushing them. Whenever you do that, give the contacts more nitric, or a whole new batch of nitric (depending on progress, time allowed/already used,...basically, your discretion).

If i were you, i would search the threads involving kurt, lou, harold, and (i cant remember who else had some great info -sorry)... These gentlemen have given GREAT info about the Ag/W contacts.

Goldsilverpro!

Thats the other... How could i forget him? Afterall, he does have experience dealing in *tons* (literally) of silver, in all shapes and forms. -an abundance of information-

-toph


----------

