# eight lbs of sterling silver



## Anonymous (Sep 2, 2009)

Hello i have been purchasing sterling silver off of craigslist and have been getting a ton of hits. I have now aqquired eight lbs of it. I know that nitric acid is expensive, as i do not have a good source around my parts. What would be the best method for refining. Also all silver is marked 925.


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## lazersteve (Sep 2, 2009)

I've had good results using copper nitrate as an electrolyte to dissolve sterling in anode form.

Of course, you will need some copper nitrate to use for the electrolyte. I use my left over copper nitrate from previous batches of silver that I have refined. 

You could obtain a small amount of nitric (1- 2.5L) and some distilled water. Dissolve a portion of your sterling, cement the silver with copper, then use the copper nitrate as an electrolyte for the rest of the sterling.

I recently dissolved 17 pounds of sterling for a customer. The customer bought the nitric as part of the job, so now I have lots of left over copper nitrate.

Steve


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## Anonymous (Sep 2, 2009)

Steve,
If you dry some of that copper nitrate out, I would be interested in buying around half a pound or so, or if you prefer metric 250 grams.

thanks
Jim


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## Anonymous (Sep 2, 2009)

Hey thanks a bunch. Yeah i live in central Illinois and these people around here don't know what they are getting rid of. I have been buying sterling silver for 100 a lb. But with the copper nitrate do you set it up like you do the cell in your videos. Thanks for the help again.


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## lazersteve (Sep 2, 2009)

James,

It's very difficult to keep copper nitrate dry as it is very hygroscopic (absorbs water from the air). For this reason I store mine in a large drum and pump it out when I need some. 

I dried a liter out once and it was welded to the beaker, I had to moisten it again to get it out of the beaker. Maybe if I try stirring the solution as it dries it won't adhere to the beaker so badly.

Vegas,

You can search the forum for 'copper nitrate' posts made by me and get the general details of the set up. All you need is a sterling bar anode, copper nitrate, battery charger, and a few pieces of hard graphite.

This is one of those projects that is on my lists of things to video, but time has not allowed me to do so yet.

Steve


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## Anonymous (Sep 3, 2009)

Steve,
did it form crystals as the water evaporated? I think that it could be possible to pick them out as it condenses down. No need to go to any great effort though.
I finally got a distillation rig and will just make some nitric, use it, then use the copper nitrate for my perposes.

thanks
jim


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## lazersteve (Sep 3, 2009)

James,

I haven't tried that, but they still absorb water very readily from the air.

I'm thinking I'll need a vacuum desiccator to get them dry.

Steve


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## Lou (Sep 5, 2009)

The best you'll be able to do in a home laboratory is get a hydrated form of the salt, probably the dihydrate. Getting anhydrous copper (II) nitrate is something of a challenge, even for a chemist!

The best way to get the salts is to pour them out into a large Pyrex dish and let them evaporate into a syrup. After that, apply heat with agitation to render them down to a wet crystal mass. This can be further dried with a vacuum pump and some heat, or just put in an oven that *isn't used for food* and the excess water evaporated off at low heat.


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