# Copper Nitrate - give away, or stock pot?



## renkenbw (Jun 13, 2019)

Anyone... I have two liters of copper nitrate after cementing out my silver and I am trying to decide if I should pour it into my silver refining stock pot, or find someone to give it to that is refining copper. What is the consensus?


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## g_axelsson (Jun 14, 2019)

Stock pot would probably be the best answer, not that I think there would be a lot of values left.

Not a consensus, just my opinion.

Nice bottles though, I use the same ones for storage of chemicals. Both for dry powders and liquids.

Göran


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## butcher (Jun 14, 2019)

You could also use it to make some nitric acid, or use it for removing base metals higher than copper in the reactivity series.


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## renkenbw (Jun 14, 2019)

Yes. These are very nice bottles! I really like them and will likely get some more. Nice and thick, and no-drip! Good tight lids too. And, "butcher", I'm counting on the stock pot for that. I have copper in there and it is already collecting sludge. I will go ahead and add this to it and let it do it's thing over time.
Thanks guys!


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## dhorne (Sep 9, 2019)

You could add some Al foil and recover the Cu.


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## theitalianhenchman (Nov 15, 2020)

butcher said:


> You could also use it to make some nitric acid, or use it for removing base metals higher than copper in the reactivity series.



I was wondering...how can be nitric acid made from this?


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## FrugalRefiner (Nov 15, 2020)

You can use electrowinning to remove copper from the solution leaving the nitrate ions behind creating nitric acid.

It's an electrolysis process like running a silver cell, but by replacing the impure silver anode material with an inert material like graphite, silver stops dissolving back into the electrolyte while the electrical current forces the metal out of solution and deposits it as a metal on the cathode.

In this case, it's copper that would be forced out of solution, but the result will still be a dilute nitric acid solution with some copper remaining.

I believe lazersteve was the first to mention it here back in 2008, though it's been used in the commercial silver refining industry for some time.

See Processing Sterling Silver without nitric acid

Dave


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## theitalianhenchman (Nov 16, 2020)

Wow..very interesting although not very easy to do for a noobs like me! seems a very good way to reduce the waste created and at the same time cut the cost of the acids..thanks for sharing!


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## butcher (Nov 26, 2020)

Copper nitrate can be reused, in a process to recover the nitric acid with a process of distillation with sulfuric acid.

distilling nitric acid from the copper nitrate solution, and at the same time, I can recover gold foils (from copper-plated pins cut into small pieces), producing a copper sulfate reagent that can be used in copper refining cells or for other uses.

This can be done by distillation of the copper nitrate solution with sulfuric acid, producing copper sulfate, and distilling off of the nitric acid.

Cu(NO3)2 + H2SO4 --> CuSO4 + 2HNO3

reusing copper nitrate waste in a process of recovery of gold, producing usable nitric acid, and making CuSO4 for use in electrolysis or for other uses:
kill two birds one rock, making HNO3, CuSO4, Gold from pins


-----------------------------------------------------------------------------------------------------------------
copper sulfate just like copper nitrate has many uses as a reagent and can be used in different recovery processes, or we can recover the copper from the solution and make a solution of sulfuric acid from this reagent.

If we wish with the use of an electrolytic cell we can also recover the copper from the copper sulfate solution (plating it out of the solution onto a copper cathode, leaving us with the sulfuric acid for reuse.

Using a platinum-coated titanium anode (purchased from a reputable seller on eBay being aware of fakes and shifty dealers).
Using a copper cathode (to plate the copper from the solution onto).
Electrolyte of CuSO4 + H2SO4 + H2O.
The voltage of around 3 volts and with a current density of around 30 milliamps per square centimeter of copper cathode area, or 100 milliamps per square centimeter of the platinum-coated titanium anode, (or whichever is smaller of the two current density).
Anode reaction:
2H2O --> 4H+ + O2 +4e-
Cathode reaction:
Cu2+ + 2e- --> Cu
Overall cell reaction:
2CuSO4 + 2H2O --> 2Cu + 2H2SO4 + O2


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## Goldenrod757 (Mar 11, 2021)

Question for the originator of the post : What/How did you ( use to ) recover your silver and yet leave Copper Nitrate behind?


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## g_axelsson (Mar 11, 2021)

Goldenrod757 said:


> Question for the originator of the post : What/How did you ( use to ) recover your silver and yet leave Copper Nitrate behind?


He cemented the silver on copper.

Göran


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## Goldenrod757 (Mar 12, 2021)

Very well. That makes sense. i havent tried that. Nor have i been particularly careful in even storing silver chloride collected. And therefore havent recovered any silver in any form so far. Except as i hinted, some silver chloride precipitated with HCl was done. Btw the Copper Nitrate mentioned can be evaporated in shallow flat containers and crystalized for easier storage. Or boiled to that state where it would crystalize upon cooling.


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## autumnwillow (Jan 22, 2022)

butcher said:


> Copper nitrate can be reused, in a process to recover the nitric acid with a process of distillation with sulfuric acid.
> 
> distilling nitric acid from the copper nitrate solution, and at the same time, I can recover gold foils (from copper-plated pins cut into small pieces), producing a copper sulfate reagent that can be used in copper refining cells or for other uses.
> 
> ...




If salt or HCl was used to precipitate AgCl from a silver nitrate solution, how can you convert the solution back to nitrate?

Sorry for hi-jacking the thread.


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## Yggdrasil (Jan 22, 2022)

I don't think you can turn AgCl back to AgNO3. But by using HCl to convert Silver nitrate to Silver chloride, you are turning the Silver nitrate back to nitric and some water.
If I understand you correct.


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## FrugalRefiner (Jan 22, 2022)

autumnwillow said:


> If salt or HCl was used to precipitate AgCl from a silver nitrate solution, how can you convert the solution back to nitrate?
> 
> Sorry for hi-jacking the thread.


Let's start with the silver nitrate solution. There are silver cations (Ag+) and nitrate anions (NO3-) floating around in the solution. It's a nitrate solution.

If we add salt (NaCl) or HCl, we're adding either a sodium cation (Na+) or hydrogen (H+), and chloride anions (Cl-). If you're careful, you'll add just enough of the salt or HCl to precipitate almost, but *not quite* all of the silver as AgCl. In this way, all of the chloride ions will precipitate as AgCl, The solution is still a nitrate solution just as it was when you started. Almost all of the silver has precipitated. All of the chloride has precipitated. If you used salt, you now have sodium cations (Na+) instead of the silver cations, so the solution is now a sodium nitrate solution with just a bit of silver nitrate. If you use HCl, you now have hydrogen ions (H+) instead of the silver, so you're back to having a solution of nitric acid (HNO3) with a little bit of silver nitrate.

It was always a nitrate solution. The nitrate anions remain in the solution throughout the process.

Dave


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## autumnwillow (Jan 23, 2022)

How about using silver nitrate as chloride scavenger if excess Cl was added?


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## Yggdrasil (Jan 23, 2022)

You are thinking excess Cl- as in AR?
It can be done, presuming the risk of excess nitrate do not lead to a worse situation than you have. Excess Cl- is usually easily mitigated.
AgNO3 cost usually more than the energy to evaporate the Cl- in the first place

It can be done as far as I see it, but that don't mean you should do it or even want to do it.
Regards Per-Ove


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## autumnwillow (Jan 23, 2022)

Yggdrasil said:


> You are thinking excess Cl- as in AR?
> It can be done, presuming the risk of excess nitrate do not lead to a worse situation than you have. Excess Cl- is usually easily mitigated.
> AgNO3 cost usually more than the energy to evaporate the Cl- in the first place
> 
> ...


I quoted butcher's post. What I'm trying to do is reduce waste, recover copper and recover nitric. But since I use Salt to get my silver from silver nitrate solutions, I don't think that will work for using butcher's method. So there must be a way to get the copper chloride solution back to silver nitrate.

As suggested by FrugalRefiner, adding the Cl slowly would work, then I now have a nitrate solution. I could use copper to cement the minimal silver left, then proceed with butcher's process.

If excess chloride was used, I could use silver nitrate as a scavenger for Cl, then cement the silver again with copper, I would now have a nitrate solution. 

I'm no chemist but correct me if I am wrong.


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## Yggdrasil (Jan 23, 2022)

autumnwillow said:


> I quoted butcher's post. What I'm trying to do is reduce waste, recover copper and recover nitric. But since I use Salt to get my silver from silver nitrate solutions, I don't think that will work for using butcher's method. So there must be a way to get the copper chloride solution back to silver nitrate.
> 
> As suggested by FrugalRefiner, adding the Cl slowly would work, then I now have a nitrate solution. I could use copper to cement the minimal silver left, then proceed with butcher's process.
> 
> ...


You are correct like that.
But the question is how much time and resources you are going to dedicate to chase the last mg of silver/copper out of solution.
When you are done with leaching and have your gold and most of the silver out. 
I guess the nitrate or if you would swap to HCl instead of salt, the Nitric would be the main carrier of value in solution.
Just my 2 centavos.


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