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extracting silver from galena

Posted by Mark & Linda Mahlum  
extracting silver from galena
August 13, 2008 04:23AM
Does anyone know of a safe way to extract silver from a galena ore? I am in possession of a couple of pounds of high grade (I think) ore.

Mark
avatar Re: extracting silver from galena
August 13, 2008 09:06AM
de    
Hello,

The way used over centuries was:

1. heating the ore to remove the sulphur (Attention: toxic and acidic exhaust fumes, very bad for the environment)
2. oxidizing the lead (heating at maximum contact with air in shallow pans)
3. getting the remaining silver from the bottom (in Germany called Blicksilber ("silver glance").

The three products you will get are sulphuric acid (or just SO2 or SO3 fumes), lead oxide (massicotite) and silver.

Another way would be to solve the galena in acid or a solution, then putting a coal (as cathode pole) and a copper (as anode pole) stick into the solution. If you put the cables at a car battery, the silver will get attracted to the copper stick. This is used as galvanic elements for coatings of e.g. Zinc on iron and for refinement of copper or silver.

Both ways aren't really save.

Regards,

Sebastian Möller
Re: extracting silver from galena
August 20, 2008 10:22PM
Would it be worth the trouble for the amount of silver you might get?

The North Pennine galena from England carried silver values from zero to maybe 40oz per ton but typically 3 to 8. It was worth extracting the silver only because they were dealing in huge tonnages of lead ore and didn't have to worry about environmental health officials breathing down their necks.

As Sebastian pointed out, the process is rather nasty and not the sort of thing to be doing in your back yard
Re: extracting silver from galena
August 21, 2008 02:26AM
There is an old method, called the Parkes process, which was used to separate silver (and gold) from lead. The argentiferous galena is first reduced to metallic lead, Then zinc is added to the molten lead, The silver is much more soluble in the zinc. The zinc rises to the surface, taking most of the silver with it. The silver/zinc alloy is then roasted to recover the silver. I don't think that the investment in the necessary equipment would be justified for treating a small amount of ore.
Re: extracting silver from galena
August 21, 2008 02:47AM
The grades in that old mine were 250-300 Oz of Ag per ton. It's not about the value of the silver, it's the discovery that matters. I won't be building a smelter in my backyard, I just want to recover a small amount of silver for the fun of it. I have a backyard of thousands of Colorado acres, but I don't want to contaminate it.

Mark
Re: extracting silver from galena
August 21, 2008 03:49PM
us    
Hello Mark....There is a process used by collectors here in New Mexico which does not require a great deal of equiptment or dangerous procedures. It'll take me a day or two to find the printout of the process (and I'm a VERY slow typist!!!) so email me at auagte2@comcast.net and I'll return the email with an attachment.

Don S.
avatar Re: extracting silver from galena
August 21, 2008 05:31PM
hi....those vapors are very dangerous...it is probably not worth the risk...Joe
avatar Re: extracting silver from galena
August 21, 2008 06:52PM
Hello,

if you want to do on a small scale use a blow pipe. See:

[www.mindat.org]. The Sulpurdioxide and lead vapours are still unhealty.

The blowpipe was used to essay the silver content od lead ore in the old days.

Volker
Re: extracting silver from galena
August 21, 2008 10:12PM
A reasonably safe method is to precipitate the silver as a chloride from acid solution, then reduce the silver chloride.. Stepwise: Dissolve the specimen in nitric acid. add sodium chloride and collect the white precipitate (a mixture of lead and silver chloride) on a coffee filter. Then add water to the precip and boil. Do this a few times. Hot water dissolves the lead chloride and leaves the silver chloride as an insoluble white material. Then dry the silver chloride and mix it with charcoal and borax. Heat the mix to red heat for several minutes in a crucible. If all goes well, you'll get a nice little button of silver. If the original sample has any mercury in it, this will come off as a vapor when you heat the crucible, so don't sniff it. Have fun.

Aloha,
Jesse
avatar Re: extracting silver from galena
August 23, 2008 03:47PM
gb    
Jesse Crawford Wrote:
-------------------------------------------------------
> A reasonably safe method is to precipitate the
> silver as a chloride from acid solution, then
> reduce the silver chloride.. Stepwise: Dissolve
> the specimen in nitric acid.

Just a reminder that dissolving any sulphide mineral in acit will liberate Hydrogen sulphide (rotten eggs smell). This gas is about 10 times as dangerous as cyanide gas - it is just as toxic with the added problem that at above a few parts per million level in air, it behaves as an anaesthetic, and you can no longer smell it.

This process should be carried out in a fume-cupboard or the open air.

The cupellation process was used to assay silver as well as extract it.

Smelt the lead/silver ore. Continue to heat with zinc (at about 10 of lead to 1 of scrap zinc). Skim off the zinc (if you let the whole lot cool together, you may be able to liberate the zinc using a hammer - the point ofd contact can be quite fragile.

Now heat the zinc in an oxygen-rich flame on a bed of bone ash. He zinc is absorbed by the ash, and at some point the bead of metal will blick, that is suddenly become very bright. This is now pure silver (around 99.98%, if the galena doesn't bear too many other zinc-soluble impurities)

Remember that lead vapour is toxic, and so is the sulphur dioxide liberated in smelting sulphide ores.

You may like to pre-roast your ore outside on a charcoal heatsource to drive off a lot of the sulphur, and any arsenic (smells like garlic, and is, guess what, hightly toxic ;) ).

Good luck with your assay.

When you invited me to see your etchings, I didn't expect to see so much degraded quartz. Really.
avatar Re: extracting silver from galena
September 02, 2008 03:41PM
de    
"Just a reminder that dissolving any sulphide mineral in acit will liberate Hydrogen sulphide."

Not, if nitric acid is used, which will oxidize the sulphide to sulphate.
avatar Re: extracting silver from galena
September 02, 2008 04:11PM
gb    
Peter Haas Wrote:
-------------------------------------------------------
> "Just a reminder that dissolving any sulphide
> mineral in acid will liberate Hydrogen sulphide."
>
> Not, if nitric acid is used, which will oxidize
> the sulphide to sulphate.

True. But there again, most folks use hydrochloric acid because of the easier availability.

By the way (and I know Peter knows better) ....

Don't try to use sulphuric acid on Galena - the reaction is halted almost immediately due to the formation of insoluble lead sulphate. (I remember a friend trying this during a chemistry class, and wondering why the sulphide didn't dissolve).

Using Nitric acid, you do need to be careful as the acid tends to get quite hot, and is liable to boil.
Of course, by dissolving argentiferous galena in nitric acid amd then filtering, the addition of hydrochloric acid to the clear solution will yield a precipitate of silver chloride which can then be filtered, washed, dried and assayed - you can even reduce this to metallic silver (I used to recover silver from laboratory waste using pyrogallic acid and white sugar but there are other approaches.)

Now, how would we proceed with auriferous ore samples, I wonder?

When you invited me to see your etchings, I didn't expect to see so much degraded quartz. Really.
avatar Re: extracting silver from galena
September 03, 2008 03:00PM
After dissolving galena in HNO3, adding HCl will precipitate BOTH silver chloride and lead chloride. Thre lead chloride can be leached out by filtering the precipitate off and boiling it in water and discarding the solution. The remaining precipitate should be boiled a couple of times more, discarding the solution each time. Silver chloride is essentially insoluble in hot water, lead chloride is fairly soluble. The remaining precipitate of silver chloride can be dissolved in ammonium hydroxide, which will leave any mercury I chloride behind, and then the silver can be reprecipitated as a chloride from the clear solution. This is fine for a qualitatve, or even quantitative test, but I doubt it is practical as a method for winning silver.
Re: extracting silver from galena
September 04, 2008 04:13AM
us    
Donald Peck's procedure is the best for seperating small quantities of silver from galena....and the safest!!! You will still have to use heat to reduce the silver chloride to silver

Don S.
Pedro Lavrador
Re: extracting silver from galena
November 07, 2008 07:01PM
May anyone of you kind Sirs/Madams explain to me how to extrac silver from wacth batteries (they contain silver oxide)?
naeem
Re: extracting galena from its ore
March 30, 2012 05:44PM
Dear
I purchased 10 tons of Galena ore (lead ore)
but unfortunately i did nt melt it
I want to use lead for acid battery
Please send me some procedure how i get lead from it ore?
Thnaks
naeemjumani@ymail.com
[email protected]
Re: extracting silver from galena
April 23, 2012 10:33PM
Don Saathoff Wrote:
-------------------------------------------------------
> Hello Mark....There is a process used by
> collectors here in New Mexico which does not
> require a great deal of equiptment or dangerous
> procedures. It'll take me a day or two to find
> the printout of the process (and I'm a VERY slow
> typist!!!) so email me at auagte2@comcast.net and
> I'll return the email with an attachment.
>
Reference to your mexico process if you can send the attachment to me i will be thankful to you.

Regards

Flocini

flocini@yahoo.com
avatar Re: extracting silver from galena
April 24, 2012 06:39AM
at    
Sebastian mentioned the silver glance (Silberblick). That reminded me of a beautiful xylographic I own.
Here`s a pic from it [www.mindat.org].
Hope you like it as I do.
Jkg
Re: extracting silver from galena
June 29, 2012 02:24AM
I have 200lb of ore that has 7.4oz ton Au and 26oz ton Ag. Here is the problem that I have. The ore has lead, zinc, moly, and some copper. I have put it in my furnace with borax, silica, and carbon. The end was a metal button the same size as the Origanle charge. I hit the button with a hammer to brack off the flux and the metal button powdered. My question is 1) how do I get the moly out, and 2) dose any one have a good flux that would help in the separation of the Au and Ag. Please Email with any advice.
Mrexploration@gmail.com
Re: extracting silver from galena
June 29, 2012 09:21AM
gb    
If you put some hydrogen peroxide in with the galena and nitric acid solution it speeds things up quite a bit. Put the nitric acid in first, then the peroxide. Or, fi you could get hold of it, you could use ziconium nitrate in water followed by the addition of hydrogen peroxide. This way, zirconium(IV) nitrate hydrolyses in water to give zirconyl nitrate and nitric acid so nitric acid is generated in situ which makes it a bit safer.

Alan
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