Refining silver nitrate into silver.

[JordanReas]

Hello all. I respect and revere all of your opinions and knowledge. I am a small refiner learning my way.

I have refined only gold filled jewelry for some time now, my process is as follows; gf jewelry in beaker, add 50/50 nitric until no brown fumes come from new solution. This nitric wash goes into my larger tanks. Then I refine the gold as hoke recommends via aqua regia.

With my silver nitrate, along with a bunch of other metal nitrates, I put copper tubes into the pots. They've been in there for about a week now. I am wondering what should my next steps be to retrieve this silver, or silver compound. It is now settled on the bottom of my tanks, kind of cloudy, kind of solid.

Any references to another thread would help, I can't seem to find any that fit my need. Also references to hoke's book, I don't think refining silver from gf jewelry is a common occurrence. Or some straight up advice would be welcome!

The gold filled jewelry I'm working with is mostly marked 1/20 12k gold filled, I also work with watch cases, pocket watches, and old Victorian gold plated items.

I have been successful in refining gold from this, thanks greatly to you guys, and hoke's book.

 

[FrugalRefiner]

With my silver nitrate, along with a bunch of other metal nitrates, I put copper tubes into the pots. They've been in there for about a week now. I am wondering what should my next steps be to retrieve this silver, or silver compound. It is now settled on the bottom of my tanks, kind of cloudy, kind of solid.

You can decant the solution leaving the solids behind. I would probably do a couple of boiling water washes, decanting those as well to remove any soluble nitrate residues. Assuming your solution was clear with no solids when you started cementing, you should have pretty clean silver. If you want to purify it further, melt it into an anode for a silver cell.

I don't think refining silver from gf jewelry is a common occurrence.

Silver and copper are commonly used in creating yellow gold alloys. The outer surface of true gold filled is alloyed gold, and will often contain small amounts of silver.

Dave

 

[JordanReas]

Thank you Dave for your reply. Remember, I am only working with gold filled, so my nitrate solution is filled with copper nitrate and many other metal nitrates along with silver nitrate. After decanting, you advise boiling water rinse, repeat decant, repeat. I will try that.

Should I stay with adding copper tube to my original nitrate solution, or is there a more efficient way to start with?

In doing the copper tube in my dirty silver nitrate, am I correct in assuming, the silver I get will not be pure? Would anyone know around the purity I will get? When I left the nitrate solution, from the gold filled acid bath, sit and settle for a while, it looked like there might have been some gold powder color. Keep in mind that I filter my used nitrate through a coffee filter into a tank.
What I had in mind is;
-put copper tubes into my used nitrate, let sit for a week
-decant, boiling water rinse. Repeat 2 more times
-force dry over a hot plate
-melt remaining powder and pour into water making shot
-nitric bath
-Aqua regia any gold remaining
-copper tubes into the cleaner silver nitrate solution
-decant, boiling water rinse. Repeat 2 times
-force dry
-melt powder into bars

Does this process make sense to anyone? Does it seem like overkill? Will the purer silver and gold pulled be worth the work? Or will I be better off pouring the powder the first time and selling as is?

I absolutely love metallurgy, and again appreciate all of your suggestions.

 

[maynman1751]

One thing that I would advise is splitting the copper tube and flatten it. The cemented silver is more difficult to remove from an intact tube shape.
If I were you, I would re-filter the nitrate solution and try and 'capture' the suspected gold powder. Filtering several times will help the filter to 'clog' and be more likely to catch the gold powder. Then cement your silver and do the hot washes. If you do catch any gold in the filter you can add that to your recovered gold or process separately.

 

[FrugalRefiner]

Thank you Dave for your reply. Remember, I am only working with gold filled, so my nitrate solution is filled with copper nitrate and many other metal nitrates along with silver nitrate. After decanting, you advise boiling water rinse, repeat decant, repeat. I will try that.

Should I stay with adding copper tube to my original nitrate solution, or is there a more efficient way to start with?

In doing the copper tube in my dirty silver nitrate, am I correct in assuming, the silver I get will not be pure? Would anyone know around the purity I will get? When I left the nitrate solution, from the gold filled acid bath, sit and settle for a while, it looked like there might have been some gold powder color. Keep in mind that I filter my used nitrate through a coffee filter into a tank.
What I had in mind is;
-put copper tubes into my used nitrate, let sit for a week
-decant, boiling water rinse. Repeat 2 more times
-force dry over a hot plate
-melt remaining powder and pour into water making shot
-nitric bath
-Aqua regia any gold remaining
-copper tubes into the cleaner silver nitrate solution
-decant, boiling water rinse. Repeat 2 times
-force dry
-melt powder into bars

Does this process make sense to anyone? Does it seem like overkill? Will the purer silver and gold pulled be worth the work? Or will I be better off pouring the powder the first time and selling as is?

I absolutely love metallurgy, and again appreciate all of your suggestions.

Where do I start?...

Yes, washes because you're cementing your silver from a very dirty solution.

Cementing on copper is good because it does not add volume to your waste stream and drops only precious metals. Cemented silver is usually 98 - 99% pure, assuming silver is the only PM in solution.

Then you start to lose me. Why do you believe you had gold dissolved in your nitric solution? If your cement is off color, it's likely base metals from the dirty solution.

Once you've cemented the silver, I'd dry it, melt it into an anode, and run it through a silver cell. Any gold will be recovered in the slimes.

Dave

 

[maynman1751]

Why do you believe you had gold dissolved in your nitric solution?

Dave, I believe that he's saying that when he decanted, some of the powdered gold got poured off. That's why I suggested filtering the nitrate before cementing. At least that's what I understood. :?:

 

[4metals]

The one thing it seems you have omitted is agitation of the solution while cementing on the copper. The reaction only takes place when the metals in solution come into contact with the copper bar. (or flattened copper tube)

One thing you can do is make a basket out of PVC pipe with a screen on the bottom to support the copper and bubble air through it to move the solution in the tank up past the copper inside the basket. The bottom needs to be open for solids to fall through and a few holes on the bottom to allow solution to flow into the tube and at the liquid level at the top to allow the liquid out.

The basket is not designed to catch the solids that drop out of solution, just to expose the copper to more solution. The more you expose the copper to fresh metal in solution, the faster it works.

 

[Palladium]

If he's using coffee filters with gold filled then some of the particles are indeed passing through and mixing with the cemented silver. You will have both foils and fine particulate with gf.

 

[kadriver]

I have refined only gold filled jewelry for some time now, my process is as follows; gf jewelry in beaker, add 50/50 nitric until no brown fumes come from new solution. This nitric wash goes into my larger tanks. Then I refine the gold as hoke recommends via aqua regia.

It might be helpful to incinerate the GF items before you commit them to 50/50 nitric treatment.

Just heat the GF material with a propane torch (or other heat source) just until it quits smoking. Try not to melt it.

By incinerating in this fashion you will burn off any residues and oils - these oils can cause problems later on.

After the nitric treatment I pour everything through a filter to capture all the foils and any gold powder.

If some powders make it through, then just pour it back through the SAME filter until the solution is crystal clear.

Then carefully remove the filter and put it in a small Corning ware casserole and burn the whole thing foils and filter until it all has been heated to redness.

Allow the dish to cool to room temp then add HCl. This makes it easier to transfer to a beaker for further processing.

Transfer this slurry to a beaker and add small amounts of nitric with low heat.

Once all the foils and powders have dissolved then pour through a filter.

The clear blue/green liquid has silver, just add copper and cement out, stirring often.

Once it's all cemented, pass it through a filter and rinse with boiling distilled water until the rinse water runs clear.

Dry and melt the cement silver and pour the molten silver into a large metal container half full of tap water.

I put a large chunk of ice made in a round cottage cheese container and let it float in the water.

I pour the molten silver onto the side of the ice chunk and it makes some nice silver shot.

kadriver