# Rinsing silver chloride



## Hartbar (May 11, 2021)

Hi all, thanks in advance.
I’m starting out with silver refining from sterling silver holloware.
Start with distilled water/nitric acid 50/50 mix.
Clean sterling, rinsed in DW, on heat plate seems to dissolve in about 2 hrs. 12/14 oz.
I precipitate with sea salt, let settle.
The issue I’m having is rinsing the sil chloride prior to adding the lye and sugar to go to oxide.
I rinse with dist water, but have to rinse so many times, I’ve tried hot distilled water, helps a bit.
Is there any way I can help my rinsing process?
I’ve read about rinsing with hydrochloride acid and also with ammonia? 
Any tips on the rinse process both at chloride stage and oxide stage would be great.
Thanks


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## Lino1406 (May 11, 2021)

Some points:
1.Your product is silver chloride, hence distilled water can be replaced with tap water
2. Consider use of AP which will give you AgCl directly
3. Lye by itself gives the oxide, sugar gives metallic silver


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## FrugalRefiner (May 11, 2021)

To add to Lino's comments, if you rinse silver chloride with ammonia, you will dissolve some or all of the silver chloride, depending on how much ammonia you use. This can form an explosive mixture, so any time silver chloride is dissolved in ammonia, it must be re-acidified promptly.

Dave


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## snoman701 (May 11, 2021)

Silver chloride is best rinsed by using water with enough HCl added to it to keep it acidic. I prefer to resuspend the AgCl multiple times, filtering off the water to get back to just a AgCl. 

If you are doing soldered sterling, you may want to use HOT water rinses so you can get rid of the lead chloride that precipitates when you add chloride as well. 

And to reiterate...no ammonia. 

But I do ask, what is the purpose of AgCl precipitation. Most like to avoid AgCl, and there are only select instances where it is worthwhile to create it.


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## Hartbar (May 13, 2021)

Thank you all again for your input.
So, I can avoid the salt precipitation by doing AP instead?
I think AP involves copper in some way?
Would the chloride from AP be different than the chloride from salt? Still rinse?
Is it the same method when rinsing the oxide created after the lye/sugar process?


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## au-artifax (Apr 4, 2022)

FrugalRefiner said:


> To add to Lino's comments, if you rinse silver chloride with ammonia, you will dissolve some or all of the silver chloride, depending on how much ammonia you use. This can form an explosive mixture, so any time silver chloride is dissolved in ammonia, it must be re-acidified promptly.
> 
> Dave


This is not true regarding the dissolution of AgCl with NH3 making an explosive compound. It is when you add NH3 to Ag20 or straight AgNO3 that will produce silver nitride. Adding ammonium hydroxide to silver chloride will not produce an explosive mixture..... ever. The real reason not to use it is because it dissolves your product and has to be reclaimed... wasting resources and time by creating additional steps in your refining efforts.


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## snoman701 (Apr 4, 2022)

au-artifax said:


> This is not true regarding the dissolution of AgCl with NH3 making an explosive compound. It is when you add NH3 to Ag20 or straight AgNO3 that will produce silver nitride. Adding ammonium hydroxide to silver chloride will not produce an explosive mixture..... ever. The real reason not to use it is because it dissolves your product and has to be reclaimed... wasting resources and time by creating additional steps in your refining efforts.



Until you let it dry.


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## Helian (Apr 5, 2022)

"But I do ask, what is the purpose of AgCl precipitation. Most like to avoid AgCl, and there are only select instances where it is worthwhile to create it."

I use AgCl precipitation to separate Ag from other metals when purifying, for example, bits of sterling silver in forms that are both difficult to clean and unsalable to most sterling buyers, such as the thin, sterling arms of triple candelabra that are filled with cement, pitch, lead, copper, etc. I melt this stuff, dissolve the metal in nitric, and then drop the AgCl with HCl. I find reducing AgCl to silver to be quite easy. If there's a better way, I'd be glad to hear about it.


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## cejohnsonsr1 (Apr 6, 2022)

Helian said:


> "But I do ask, what is the purpose of AgCl precipitation. Most like to avoid AgCl, and there are only select instances where it is worthwhile to create it."
> 
> I use AgCl precipitation to separate Ag from other metals when purifying, for example, bits of sterling silver in forms that are both difficult to clean and unsalable to most sterling buyers, such as the thin, sterling arms of triple candelabra that are filled with cement, pitch, lead, copper, etc. I melt this stuff, dissolve the metal in nitric, and then drop the AgCl with HCl. I find reducing AgCl to silver to be quite easy. If there's a better way, I'd be glad to hear about it.


You could just cement the silver out on copper. Same result with 2 less steps.


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## orvi (Apr 6, 2022)

cejohnsonsr1 said:


> You could just cement the silver out on copper. Same result with 2 less steps.


Quicker, but less pure. Most of us go through the cell anyway, but from AgCl 99,9% purity is quite easy to achieve, if washed throughly. My average from Cu cementation is 98,5%.
When refining pure material, cementation is certainly a way for me. But from complicated junky mixtures of dissolved contact points with lots of lead and possibly palladium - I selectively precipitate AgCl and then deal with the rest.


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## snoman701 (Apr 6, 2022)

Lead is the pain with chloride precipitation. Just one more step to heat it then filter it hot.


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## cejohnsonsr1 (Apr 7, 2022)

orvi said:


> Quicker, but less pure. Most of us go through the cell anyway, but from AgCl 99,9% purity is quite easy to achieve, if washed throughly. My average from Cu cementation is 98,5%.
> When refining pure material, cementation is certainly a way for me. But from complicated junky mixtures of dissolved contact points with lots of lead and possibly palladium - I selectively precipitate AgCl and then deal with the rest.





orvi said:


> Quicker, but less pure. Most of us go through the cell anyway, but from AgCl 99,9% purity is quite easy to achieve, if washed throughly. My average from Cu cementation is 98,5%.
> When refining pure material, cementation is certainly a way for me. But from complicated junky mixtures of dissolved contact points with lots of lead and possibly palladium - I selectively precipitate AgCl and then deal with the rest.


Lead is above copper on the reactivity series, so it shouldn’t cement out on copper. I could see going this way if there was a definite significant quantity of PGMs, but most scrap only contains very small amounts of gold and PGMs, which get captured in the slimes from the cell. For most purposes, I just don’t see any benefit to this method. Especially if the product is going to be run through a cell anyway. Copper is relatively cheap and cementing is straight forward and pretty quick.


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## orvi (Apr 7, 2022)

cejohnsonsr1 said:


> Lead is above copper on the reactivity series, so it shouldn’t cement out on copper. I could see going this way if there was a definite significant quantity of PGMs, but most scrap only contains very small amounts of gold and PGMs, which get captured in the slimes from the cell. For most purposes, I just don’t see any benefit to this method. Especially if the product is going to be run through a cell anyway. Copper is relatively cheap and cementing is straight forward and pretty quick.


Yep. There aren´t many situations when you benefit from using lye/sugar. If you are running it through the cell. Because cell has it´s own difficulties arising from running it. Replacing electrolyte, keeping eye on copper concentration, keeping eye on whiskers, anode bag replacements, preparing pure silver for electrolyte, difficult elimination of palladium from crystals (if Pd is present in more than ppm quantity - it always co-deposit with Ag) etc... Looking to the other side, NaCl is practically no cost, washing take only hot water, and then the only cost is NaOH and bit of sugar. Very low-tech and it could be very effective for preparing pure silver of 99.9% purity, if done correctly. This is often more than enough for sale or use. So with lye/sugar you can very effectively and completely eliminate whole purifying procedure. And you can easily run 1 kg batches in regular PP bucket. In 5 gallon bucket, I wouldn´t be afraid of 1,5-2 kg at once - so 1-1,5 kg of silver took somwhere near 2 hours of work if you have it optimized. 6-7 kg of refined silver in a day easily.

Additionally, you can use caustic and oxidizing flux to wash remaining impurities from the metal - espetially copper. Using Na2CO3 with small addition of nitrate could eliminate practically all copper from the melt to the slag.

Cell is a standard, but I can imagine using only lye/sugar, Fe/H2SO4 tumbling or more "chemically correct and tame" formate reduction methods, and having customer who is perfectly OK with 99,9% purity. Premium is on the crystal, that´s for sure. But for many purposes, these very basic and simple methods could bring you to the desired product, omitting one whole procedure and setup.


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## billgold (Apr 8, 2022)

Why are you using sea salt? You are introducing a lot of minerals that pure sodium chloride does not contain. That cannot be optimal for obtaining the purest product possible.


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