# Silver from Silver Sulfate



## mojojtp (Apr 20, 2011)

Greetings GRF'ers...I'm a newbie looking to tap your vast expertise for a relatively simple method to convert lab grade Silver Sulfate powder to elemental Silver. Beacuse I'm in the small quantity lab chemical disposal business, I have access to reagents not normally available to most consumers, so that part of the equation is not a problem. Any assistance or guidance would be greatly appreciated. Thanks.


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## lazersteve (Apr 21, 2011)

You can melt it with soda ash or you can convert it to silver powder with diluted acid and a base metal like iron, aluminum, or zinc.

I have a video of the wet process on my website.

There is also the lye and sugar method, but I've never tried it on silver sulfate.

Steve


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## mojojtp (May 3, 2011)

Thanks lazersteve...I'll check out your site soon...gotta find myself a small muffle furnace to do the high temp work...I'm not comfortable doing a lot of blowtorch processing, for now...'til next time...mojojtp (Jerry)


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## babytrilly (May 8, 2011)

This is my first attempt at refining. I took sterling silver and dissolved it in HNO3 (50/50 with H2O). I was going to use the sodium formate method to precipitate the silver. In the process of trying to get rid of any Pb, I think I got carried away with using too much H2SO4 and most likely have a lot of silver sulfate. I don't know now how much is silver sulfate vs. lead sulfate. Tomorrow I will drop the silver out of the rest of the solution using the sodium formate. However, I would appreciate some advise on the sulfates I formed. What would you advise I do with them? I would like to eliminate any lead present before dropping the silver. However, if that is not easy, I could re-refine afterwards.

I have rinsed the white (cheesy looking) precipitate but I'm sure there is still some silver nitrate present. I can rinse some more and vacuum filter to get it as clean as possible.
Lazersteve says


> You can melt it with soda ash or you can convert it to silver powder with diluted acid and a base metal like iron, aluminum, or zinc.


. Can you elaborate on the procedure? What acid? How dilute? What conditions, if any, will keep the lead sulfate from going into solution?

There is nothing like messing up something to really make you pay attention. When people advised on using "a little" sulfuric, I think they REALLY meant "a little". I had about 2 gallons of silver nitrate solution, and a mind set that I probably had a lot of lead in my scrap. I got carried away thinking I was dropping only lead!

Thank you in advance for any advise.


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## lazersteve (May 8, 2011)

Wash the salt with hot water several times to remove the lead chloride from the silver chloride.

I have a video of the conversion of silver chloride to silver metal using acid and iron on my website:

http://goldrecovery.us

Steve


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## Harold_V (May 9, 2011)

Lead sulfate, not lead chloride. 

What may work is to dissolve the material in ammonium hydroxide, which will dissolve silver chloride, but not lead sulfate. Filter, then re-precipitate the silver from the ammonium solution by introducing HCl. 

I don't know if ammonium hydroxide will dissolve silver sulfate. If it won't, you may have to reduce the material in a furnace, using the appropriate flux, then cupel the material to eliminate lead. 

Harold


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## Lou (May 9, 2011)

Re-cement the silver sulfate with copper bar.


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## babytrilly (May 9, 2011)

> What may work is to dissolve the material in ammonium hydroxide, which will dissolve silver chloride, but not lead sulfate.



I have no chloride whatsoever. I'm a bit confused by the advise.

Silver sulfate is essentially insoluble in water, so how can I make a solution and cement with Cu?

Thanks


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## lazersteve (May 9, 2011)

You may want to try allowing a sample of your silver compound to sit overnight in a dilute solution of HCl or H2SO4 with a bar of iron in the beaker. It may work the same as the silver chloride conversion I mentioned.

If not you can try reducing the silver compound to metallic silver with soda ash in a furnace.

Sorry for the confusion with the chloride, but some of the same reactions may work the same for various silver compounds.

Steve


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## qst42know (May 9, 2011)

Is the wiki correct that silver sulfate is soluble in nitric? If so you could start over.

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

Or, I think GSP posted something a long while ago from the Philadelphia mint. Silver sulfate from a dilute solution with iron?

It was quite a while ago, a link to an old text. I'm not finding the post as I remember it.


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## Lou (May 25, 2011)

What is soluble in water will cement and more silver sulfate will go into solution until it is all gone and a copper sulfate solution remains.


It's not entirely insoluble in water, especially hot water with some sulfuric present...


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## saadat68 (Nov 13, 2017)

Hi
I have some silver sulfate in my silver cements 
Can I use iron and dilute sulfuric acid to convert them to silver metal ?

Or is it better melt them with some soda ash?


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## butcher (Nov 13, 2017)

Iron and flux in your melt, the iron will reduce the silver, iron will not mix with silver in the melt, iron will take on the sulfides.


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## saadat68 (Nov 13, 2017)

Thanks
What flux? Soda ash ? With some iron swarf?

Can I add iron in my solution with dilute sulfuric acid? (like silver chloride)


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## Lou (Nov 13, 2017)

Just stir silver sulfate with iron pieces.


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## saadat68 (Nov 26, 2017)

Thanks
I converted them to silver completely


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## BSGMiner (Sep 9, 2019)

Is the only reason that the cement silver doesn't convert right back into silver sulfate because the iron is a higher reactivity metal, which keeps taking the sulfides instead of the silver?


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## Lou (Sep 9, 2019)

More or less. 

To make silver sulfate from silver metal would require oxidation of silver and reduction of sulfate in sulfuric acid with production of SO2. Not easily accomplished except for boiling, concentrated acid. Let’s just say nitric acid is the lesser of two evils, in this case...


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## BSGMiner (Sep 9, 2019)

Lou said:


> ...To make silver sulfate from silver metal would require oxidation of silver and reduction of sulfate in sulfuric acid with production of SO2. Not easily accomplished except for boiling, concentrated acid...


That's good to know. I only have 35% H2SO4 (battery acid), which I was going to dilute to 10% (e.g. 250mL H2O + 100mL H2SO4) and stir a few common steel nails around in it (hopefully with a soon-to-be-purchased magnetic stirrer). 8)

Is there any time sensitivity to that process, or should I wait until it seems to be done trying to dissolve the nails?

Also, is there a calculation that could determine whether 350mL of 10% H2SO4 is enough for an inch of silver chloride in the bottom of a mason jar?


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## Lou (Sep 11, 2019)

For me, it was always more empirical...

Usually was done in a few hours but I don't see longer hurting anything. The sulfuric doesn't dissolve nails very fast, it's more the contact with oxidized silver in the presence of the acid that dissolves the iron so quickly.


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## snoman701 (Sep 12, 2019)

Stirring in the presence of iron didn’t work for me. I still had agcl present.

I had to tumble the silver chloride with iron as the grinding media.

You need intimate contact between the agcl and the iron.


Sent from my iPhone using Tapatalk


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## BSGMiner (Sep 12, 2019)

snoman701 said:


> ...You need intimate contact between the agcl and the iron...


Well, I have a magnetic stirrer on the way to my house by tomorrow at 8pm, so we'll see if that works better than just hand-stirring everything around while it's reacting.


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## anachronism (Sep 12, 2019)

BSGMiner said:


> snoman701 said:
> 
> 
> > ...You need intimate contact between the agcl and the iron...
> ...



Yes that's a good start it does work better.

Jon


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## snoman701 (Sep 12, 2019)

BSGMiner said:


> snoman701 said:
> 
> 
> > ...You need intimate contact between the agcl and the iron...
> ...


It didn’t work for me. 

Short of preparing hard to dissolve solids, I do not find magnetic stirrers to be of great use in refining.




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## BSGMiner (Sep 12, 2019)

snoman701 said:


> ...I do not find magnetic stirrers to be of great use in refining...


I'm going to try it for alternating HCl and H2O washes/rinses this weekend to see how that goes first.


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