Safety of evaporating depleted silver/copper nitrate

[rightmirem]

I had a silver refining cell running using 50g/L silver nitrate. The solution got very corrupted with coper and silver chloride - so I decided to start afresh with new silver nitrate. This is regarding the corrupted solution.

The solution certainly had a lot of copper in it (I'm assuming copper nitrate) because I processed some sterling silver. The solution went very blue.
It also developed some silver chloride, probably from water contamination.

I precipitated out the silver by adding 1 part NaCL and 2 part KCl salt, let it settle, and decanted the remaining (still blue) solution off. The silver chloride will be processed later.

I tried to precipitate out the copper by adding sodium bicarbonate, but it did nothing. So at this point, I just want to evaporate the solution to powder in a disposable vessel, and dispose of the copper (and whatever else) properly as solid waste.

---

QUESTION: Assuming the solution remains below 100c, my understanding is that evaporating the solution produces no airborne nitrates, nor NO2. Just water vapor. Is this correct?

I'm currently evaporating it in a closed, well ventilated room, but I don't have a hood.

Can someone confirm I'm not putting airborne contaminants into the air with this method?

 

[Yggdrasil]

I had a silver refining cell running using 50g/L silver nitrate. The solution got very corrupted with coper and silver chloride - so I decided to start afresh with new silver nitrate. This is regarding the corrupted solution.

The solution certainly had a lot of copper in it (I'm assuming copper nitrate) because I processed some sterling silver. The solution went very blue.
It also developed some silver chloride, probably from water contamination.

I precipitated out the silver by adding 1 part NaCL and 2 part KCl salt, let it settle, and decanted the remaining (still blue) solution off. The silver chloride will be processed later.

I tried to precipitate out the copper by adding sodium bicarbonate, but it did nothing. So at this point, I just want to evaporate the solution to powder in a disposable vessel, and dispose of the copper (and whatever else) properly as solid waste.

---

QUESTION: Assuming the solution remains below 100c, my understanding is that evaporating the solution produces no airborne nitrates, nor NO2. Just water vapor. Is this correct?

I'm currently evaporating it in a closed, well ventilated room, but I don't have a hood.

Can someone confirm I'm not putting airborne contaminants into the air with this method?

I'm a bit puzzled.
Why did you use KCl??
NaCl, HCl or any Chloride will do.

Have you read the thread dealing with waste?
You can cement out any Copper using Iron.

 

[rightmirem]

I'm a bit puzzled.
Why did you use KCl??

Honestly, because that's what I had on hand I'm just a "kitchen lab."
LoSalt

NaCl, HCl or any Chloride will do.

Have you read the thread dealing with waste?

I have not. Where can I find it?

You can cement out any Copper using Iron.

I will try that. I have some iron powder. Can I use that, or is an iron plate better?

Google tells me this will create Iron(II) nitrate (Fe(NO₃)₂), Iron(III) nitrate (Fe(NO₃)₃), and NO3- in solution. All of these have specific requirements for disposal in Germany, and solid waste disposal is easier. Which brings me back to my original question...

Does evaporation below 100c keep the nitrates in solution, or do they become airborne?

 

[4metals]

The iron cements copper from chloride solutions not nitrate solutions. You can raise the pH to 10 and drop copper hydroxide but this is usually done with liquid caustic, not normally in kitchen labs.

 

[rightmirem]

The iron cements copper from chloride solutions not nitrate solutions. You can raise the pH to 10 and drop copper hydroxide but this is usually done with liquid caustic, not normally in kitchen labs.

Good to know.

Again, honestly, I have no desire to collect the copper for use. My only goal here is disposal.

I can't dispose the solution as a liquid, so I want to dehydrate it, so I can dispose of it as a solid.

Is it safe to evaporate the solution, or am I putting nitrates or NO2 into the air?

 

[Martijn]

Good to know.

Again, honestly, I have no desire to collect the copper for use. My only goal here is disposal.

I can't dispose the solution as a liquid, so I want to dehydrate it, so I can dispose of it as a solid.

Is it safe to evaporate the solution, or am I putting nitrates or NO2 into the air?

Butcher would have said: nitrates are not waste!

Copper nitrate decomposes at about 80 degrees. So keep it under that temperature to evaporate and end up with copper nitrate crystals in between the other stuff you've added.

If you want to dispose of it, neutralize it so that the nitrates bond to sodium or something else.

i don't know if adding potassium chloride has changed the copper nitrate into copper chloride and potassium nitrate, but that's a possibility i think. If you keep adding soda ash or lye to raise pH, you will bind the nitrates to sodium and the copper will form hydroxides.

Treat it as waste as Yggdrasil said?

 

[Yggdrasil]

Honestly, because that's what I had on hand I'm just a "kitchen lab."
LoSalt




I have not. Where can I find it?

I will try that. I have some iron powder. Can I use that, or is an iron plate better?

Google tells me this will create Iron(II) nitrate (Fe(NO₃)₂), Iron(III) nitrate (Fe(NO₃)₃), and NO3- in solution. All of these have specific requirements for disposal in Germany, and solid waste disposal is easier. Which brings me back to my original question...

Does evaporation below 100c keep the nitrates in solution, or do they become airborne?

Hmm, I see you slipped through the cracks and did not get my welcome post with the links to study.

Anyway here they are and the link in question is one of them:

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: https://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=19798
2. Then read the safety section of the forum: https://goldrefiningforum.com/forums/safety.47/
3. And then read about "Dealing with waste" in the forum: https://goldrefiningforum.com/threads/dealing-with-waste.10539/

Suggested reading:
https://goldrefiningforum.com/forums/the-library.101/
https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
https://goldrefiningforum.com/threa...le-read-this-before-you-post-about-ore.33333/


Forum rules is here.
https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/

 

[rightmirem]

Hmm, I see you slipped through the cracks and did not get my welcome post with the links to study.

Anyway here they are and the link in question is one of them:

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: https://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=19798
2. Then read the safety section of the forum: https://goldrefiningforum.com/forums/safety.47/
3. And then read about "Dealing with waste" in the forum: https://goldrefiningforum.com/threads/dealing-with-waste.10539/

Suggested reading:
https://goldrefiningforum.com/forums/the-library.101/
https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
https://goldrefiningforum.com/threa...le-read-this-before-you-post-about-ore.33333/


Forum rules is here.
https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/

Thank you!

 

[kurtak]

The iron cements copper from chloride solutions not nitrate solutions

I am going to have to disagree with this as I have cemented LOTS of copper from nitrate solutions with iron

In fact iron is all I have ever used to cement copper from nitrate solutions - mostly the copper nitrate solutions I end up with after cementing silver out of silver nitrate solutions with copper

It works best if you use fine iron like steel wool or thin sheet iron like the sheet iron mounting brackets/cages used to mount components (floppy drives CD/DVD reader/writers etc. etc.) inside of computer towers &/or vegetable/soup cans rather then heavier/thicker pieces of iron like "slabs" of iron or rebar

It does create "some" iron oxide (rust like goo) mixed in with the copper cement but that can ether be washed out with a cold HCl wash &/or will slag off in a smelt off the copper cement --- I say "some" iron oxide (rust) as much of the iron will go/stay in solution which can then be removed from the "dissolved" iron nitrate with sodium hydroxide &/or carbonate (baking soda) to clean up the (dissolved) iron nitrate solution for safe disposal

I save all of my vegetable/soup cans just for this very purpose

Aluminum on the other hand will not cement copper from copper nitrate

Kurt

 

[4metals]

In fact iron is all I have ever used to cement copper from nitrate solutions - mostly the copper nitrate solutions I end up with after cementing silver out of silver nitrate solutions with copper

I have tried this unsuccessfully with rebar and iron slabs for spent Silver electrolyte and it never worked. The original waste treatment method I posted years back works well for spent aqua regia but not for Silver electrolyte. I always saw this process as working best for smaller processors and most of my experience is with larger refiners using classic destruct waste treatment techniques.

Lazersteve has posted about removing copper from nitrate solutions but I never found the posts and I suspect they are on his server and not accessible to us here.

Since you have experience with this using thin sheet iron, and I trust your knowledge on the matter, I would appreciate it if you would post your method, step by step, so more members can try it.

 

[rightmirem]

I am going to have to disagree with this as I have cemented LOTS of copper from nitrate solutions with iron

In fact iron is all I have ever used to cement copper from nitrate solutions - mostly the copper nitrate solutions I end up with after cementing silver out of silver nitrate solutions with copper

It works best if you use fine iron like steel wool or thin sheet iron like the sheet iron mounting brackets/cages used to mount components (floppy drives CD/DVD reader/writers etc. etc.) inside of computer towers &/or vegetable/soup cans rather then heavier/thicker pieces of iron like "slabs" of iron or rebar

It does create "some" iron oxide (rust like goo) mixed in with the copper cement but that can ether be washed out with a cold HCl wash &/or will slag off in a smelt off the copper cement --- I say "some" iron oxide (rust) as much of the iron will go/stay in solution which can then be removed from the "dissolved" iron nitrate with sodium hydroxide &/or carbonate (baking soda) to clean up the (dissolved) iron nitrate solution for safe disposal

I save all of my vegetable/soup cans just for this very purpose

Aluminum on the other hand will not cement copper from copper nitrate

Kurt

Thats good to know.

Question...

By using iron to cement the copper nitrate to copper metal, you (in theory) end up with a solution of iron nitrate (presumably equal moles to the copper nitrate.) You then mention cementing the iron nitrate with Sodium Bicarbnate.

I'm assuming that this then leaves you with a molar equivalent solution of Sodium Nitrate. It that correct?

 

[Yggdrasil]

Thats good to know.

Question...

By using iron to cement the copper nitrate to copper metal, you (in theory) end up with a solution of iron nitrate (presumably equal moles to the copper nitrate.) You then mention cementing the iron nitrate with Sodium Bicarbnate.

I'm assuming that this then leaves you with a molar equivalent solution of Sodium Nitrate. It that correct?

No not cementing, dropping it out of solution as Hydroxides.
If done right, one can a liquid solution that is "safe" to dispose of.
And all contaminants as solids.
It is outlined in dealing with waste.

 

[FrugalRefiner]

Lazersteve has posted about removing copper from nitrate solutions but I never found the posts and I suspect they are on his server and not accessible to us here.

Is this the one? Processing Sterling Silver without nitric acid

Dave