# Ultrasonic wash?



## qst42know (Sep 20, 2010)

Has anyone used an ultrasonic cleaner to rinse the copper nitrate from cement silver?

There's no lumps, just a very fine very white sediment. 

I only have a very small jewelery cleaner (40khz.) and placed a beaker of cement silver from a small experiment right in the plastic basket. Some of the bigger units have optional beaker racks. When running the water looks like skim milk but settles fairly fast.

If copper nitrate is mechanically trapped in cement silver this may work to eliminate nearly all of it.

Anyone have a well equipped lab to test the resulting purity?


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## Harold_V (Sep 21, 2010)

I found I got pretty decent results by simply rinsing the material with tap water after removing the copper used for cementation. Stir, allow to settle, decant, and repeat. Once the solution was quite clear, I generally put the recovered silver in a Buchner funnel, where it could be rinsed a final time, and tamped down well so all of the free water was removed. I then force dried the cement silver over a low flame, using a Coors evaporating dish. It's surprising that if your silver nitrate solution had a small amount of free nitric acid present, that the silver will emit traces of brown fumes once you have eliminated all of the water. 

I'm not suggesting that my method is as good as using an ultrasonic, but it did seem to do a satisfactory job. Of course, once melted, a small amount of borax was always added, to remove traces of copper oxide. 

Harold


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## qst42know (Sep 21, 2010)

I wonder if you could reduce the number of rinse cycles using ultrasonics and in turn reduce the waste volume?

I lost track of the number of times I rinsed this. It didn't seem to get any cleaner after about 3 times, but it was quite fascinating watching the sound waves powder the silver sponge like curds. 8) 

4metals what is the going rate for having waste solution hauled away?


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## 4metals (Sep 21, 2010)

If you are a business and have an EPA ID# you're looking at $5/gallon in 3 to 4 55 gallon drum quantities.

I don't see the problem you're having with rinsing. To cement silver I always use slabs of copper so no pieces break off. I do a quick rinse in a buchner and melt it into an anode. If you're trying for higher purity so you don't need the silver cell, drop it as a chloride and go the sugar route. Still uses a lot of rinse water. And the PGM's, if any, are still in the acid.


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