# Silver chloride/nitrate



## maynman1751 (Jul 26, 2012)

I have some silver/copper nitrate. I added a little HCl and got the white cloud, so I added a little more HCl. Now it appears that all of the silver precipitated out!? What do I have....silver chloride or silver nitrate?


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## publius (Jul 26, 2012)

You have silver chloride and copper chloride in the majority, there is still some silver and copper nitrate in solution. The silver will not be worth recovering unless you have tons of solution.

Remember the admonition to reduce AR three or more times to remove the nitric acid? That is why you still have (some of those metals as nitrates.


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## martyn111 (Jul 26, 2012)

maynman1751 said:


> I have some silver/copper nitrate. I added a little HCl and got the white cloud, so I added a little more HCl. Now it appears that all of the silver precipitated out!? What do I have....silver chloride or silver nitrate?



Was there a reason that you wanted to produce silver chloride?
Most of us try to avoid silver chloride because by producing it you increase the number of processes that you need to complete to produce refined silver.

The usual advice would be to cement the silver out of solution as metalic silver using a copper bar, the result would be metalic silver and copper nitrate, the silver being 99%+, which can be melted into an anode and refined through a silver cell or used as is for inquartation.

With the silver chloride you have produced you will need to put it through the sodium hydroxide and sugar process or dilute sulphuric acid and iron process to produce metalic silver for either anodes or inquarting.


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## maynman1751 (Jul 26, 2012)

I actually did not do it on purpose. I had already cemented with copper, but apparently didn't leave it long enough to clear the solution. I just wanted to test for silver with HCl. Once I had put some in, the silver started to drop out of solution. I didn't really know what to do at that point, so I just dropped the rest. There isn't a large amount of silver present, so I'm not too alarmed. Just wanted to know which took precedence.....Nitrate or Chloride.


> Remember the admonition to reduce AR three or more times to remove the nitric acid? That is why you still have (some of those metals as nitrates.


It was straight Nitric not AR. All of the nitric had been used up prior to adding the HCl.
This is the first time that I have had to deal with silver in solution. Now I get to practice getting it back to elemental. I have watched Lazersteves videos and am prepared to try the sulfuric/iron way. Thanks guys for your responses.


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## MysticColby (Jul 26, 2012)

I used to add NaCl to "depleted" silver nitrate solution after cementing all I could using copper (it does the same as HCl - converts silver nitrate to silver chloride). I'd usually get a little silver chloride precipitate, to which I would convert to silver and add to the cemented silver, then cast into bars. After doing this twice I had enough and decided to just have a bucket with all the "depleted" silver nitrate, add copper bar, wait a week, pour off supernatent occasionally.
Copper will eventually precipitate all of the silver, but the last little bit takes longer. Adding a chloride will also precipitate all the silver, just faster and require more work once in silver chloride form.
(of course, when I say 'all', I mean 'reasonably all'', as silver chloride has a solubility of about 2mg/L)

If you have a solution of "depleted" silver nitrate and you add HCl and no cloud appears, all of the silver has been removed. That is a test that has been recommended for seeing if cementing is done.


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## martyn111 (Jul 26, 2012)

maynman1751 said:


> I just wanted to test for silver with HCl.



That explains it. Its good practice to test solutions that you think are barren.
I personally use the same method as MysticColby, a stockpot for spent silver nitrate containing metalic copper to cement out any remaining silver in solution.


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## maynman1751 (Jul 26, 2012)

martyn111 said:


> maynman1751 said:
> 
> 
> > I just wanted to test for silver with HCl.
> ...


Live and learn. Like I said, it was my first experience with silver! Not my first screw up....not my last! Thanks Guys! John.


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## RESET (Jul 27, 2012)

Just curious. If you add HCl to a Silver or Copper Nitrate solution, is the product; Hydrogen gas, Silver/Copper Chloride and Nitric Acid? Might be another way to get Nitric Acid back but Steve's electrolysis way would probably be cheaper.


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## butcher (Jul 27, 2012)

You would form a form of aqua regia, silver chloride which is insoluble would precipitate out and leaving the copper dissolved in the aqua regia solution, a portion of the acid (hydrogen) from the HCl would again form nitric acid in solution from the silver nitrate in solution, as the silver forms a chloride precipitant, the nitric in solution with the free HCl would become a solution of aqua regia (keeping copper in solution).

But if the exact molar ratio of HCl were added to silver nitrate (not considering copper here), the silver chloride would form a precipitated silver chloride, then solution would then become nitric acid (considering there was no free HCl was left in solution).

AgNO3 + HCl --> AgCl + HNO3


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## RESET (Jul 27, 2012)

Thanks Butcher. I knew I was missing something. Some how I thought the Cl would knock the Copper out too. Oh well, was just curious.

So this is false, CuNO3 + HCl --> CuCl + HNO3


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## MysticColby (Jul 27, 2012)

I thought that might be the case that nitric was formed by that reaction!
I was under the impression that copper nitrate also reacted with the HCl to form copper chloride, but that it remained in solution and could also react with silver nitrate to form silver chloride, so it didn't matter if it reacted first. If that is the case, then that should also form new nitric.
I would expect 'copper chloride' in this case to be CuCl2, fyi.
And for the NaCl addition, you get sodium nitrate as a product instead of nitric.


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## lazersteve (Jul 27, 2012)

I routinely use my silver nitrate solutions for dissolving gold once I have added HCl and filtered. I always add additional HCl to the gold foils before adding the filtered leftover precipitated silver solution. You would be surprised how much nitric you can conserve recycling the waste solution this way. 

This method works especially well on ceramic cpus: 

1) Treate the broken cpus without metal (ceramic lids ok after removed) lids with 50/50 nitric acid until no more reaciton occurs and the cpu legs all fall off.
2) Filter free of debris 
3) Add HCl, stir and allow to settle and add a few more drops of HCl after a few minutes to be certain the silver is all out.
4) Alow the silver chloride to settle completely and pour off the colored solution.
5) Filter this colored solution and use for dissolving the loose gold foils and legs from the ceramics with some additional HCl.

Steve


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