# Recrystallization of AgNO3



## solar_plasma (Oct 22, 2013)

While I am reading this book http://books.google.de/books?id=eGkvSDAqY9gC&printsec=frontcover&hl=de#v=onepage&q&f=false

I stumbled over that AgNO3 is extremely soluble: 
215g/100ml water at 20°C
910g/100ml water at 100°C

Perfect for recrystallization as a technique of purifying, I would say, - presumed you have maybe 1 kg of AgNO3 .

Everthing has a good reason in refining, I have learned. So, can anybody tell me, why this method isn't used in refining?


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## solar_plasma (Oct 22, 2013)

Ok, I found it:

copper nitrate has an even greater solubility

267g/100ml at 20°C
1270g/100ml at 100°C


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## Lou (Oct 22, 2013)

Typically, already rather pure AgNO3 is melted in stainless steel and held at a high temperature--other metals form their oxides but AgNO3 is rather temperature stable. This is then poured into distilled water, the solids allowed to undergo sedimentation and then the whole mess is recrystallized into very high purity silver nitrate.


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## solar_plasma (Oct 22, 2013)

:shock: THIS is interesting! It melts at 212°C. Sounds like a nice school experiment. Thanks, Lou!


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## Lou (Oct 22, 2013)

Ehh, I wouldn't call anything with silver salts a school experiment. Most schools in the US have gotten rid of it because of RCRA.


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## solar_plasma (Oct 22, 2013)

I still have an old silver quarter I got from my dad when I was around 8 years old, - the first english word I read was "Liberty"

Luckily, it is allowed in schools in germany and denmark. In this case I would call it a demonstration experiment processed by the teacher.


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## solar_plasma (Oct 22, 2013)

"Resource Conservation and Recovery Act"....

none of "my" silver will ever leave the school and especially not as "hazardous *waste*" - it gets recycled in situ. :shock:


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## solar_plasma (Oct 22, 2013)

" Substances with Greater
Hazardous Nature Than Educational Utility"

...so, that's what the colleages over there call it  

I guess a hammer and a screw driver are "Tools with Greater
Hazardous Nature Than Educational Utility" :lol:


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## solar_plasma (Oct 22, 2013)

How do they test on chlorides?? By tasting, because all allowed school chemicals can be eaten?

*have to cool down again* :shock:


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## Lou (Nov 12, 2013)

The main issue is that silver ion is so toxic to microorganisms that are used at the public waste water treatment facility--very little silver has very big consequences!

This is why anyone working with silver must always keep their waste solutions separate and make sure that they are disposed of properly. 


And silver is great at testing for chlorides! ;-)


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