# Need some direction on AgCl



## Bushka (Dec 25, 2012)

Wow! What a forum! I've been looking around for a place where people know about small scale refining, and I finally found this place. I've learned so much already!

I need a little advice. I should say that I have a background in chemistry, but not in refining silver. I "acquired" two bottles of AgCl powder in high school lab about 30 years ago. Since then it has remained in the basement. Well finally I got around to refining it into silver, and here I am. I don't have much of the lab equipment I had at one time, only a few small beakers, and I'd like to refine the AgCl with as little investment as possible. I'm not sure I will ever refine again after this batch is gone, but then again I might be getting the bug. If I could find a decent source of silver, I'd probably keep at the refining game. So here's what I've done so far:

1. Took the "dirty" AgCl and washed it first in plain water (and also a little ammonia) to dissolve any copper salts and other misc unknowns. (There were some green flakes in the powder).
2. Washed the AgCl in HCl - muriatic acid, flushed with water, and dried the AgCl. There is still some acid dried in with the AgCl.
3. Not having a mortar and pestle, I pulverized the AgCl as best I could with a plastic sheet and a hammer. I screened this through a kitchen strainer to get a fairly small particle size. I would say most of the AgCl is powdery, while some is small and granular.
4. I recovered both AgCl and silver metal from the various washes performed above.

So that's where I stand now. In the photo, I've got about 800 grams of AgCl (the lumps are just powdery clumps from drying, not hard chunks). Also shown is some silver electrolyzed, plus other silver dropped from copper in the various solutions.

I've got a battery charger which runs at 12v and 2a/10a.

I've read over as much as I could about the difficulties processing AgCl, and so I'm posting here to see if anybody would mind critiquing my plan to move forward.

Here's what I was planning to do:

1. Combine all the silver and dissolve in a minimum of nitric acid, then dilute and drop out with copper. The idea is to clean up the silver of unknown purity.
2. Try to convert the AgCl to AgO with lye and then to silver with Karo syrup. Dissolve the silver with nitric acid in order to separate the silver from unprocessed AgCl.
3. Repeat step 2, possibly pulverizing the AgCl along the way, until all the AgCl is processed.
4. Drop out all silver in solution with copper to purify, then consider electrolysis to get 999's or better (but that's another story).

My thought is that I'm not doing this long term for 1000's of ounces of silver, so I don't mind if it takes a long time to convert the AgCl. I am aware of the problems converting dry AgCl, and am open to suggestions of using other methods like sulfuric acid and iron, for example. In general, though, I don't want to spend $100 on reagents if I can do it for less. Nitric acid is a bit pricey and I don't know exactly how much I would need to dissolve the AgCl in multiple steps as described above. Who knows, it might be easier than I think since much of it is pretty powdery.

I think that about covers it. Thanks for any comments, Merry Christmas and Happy New Year!

Dan


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## philddreamer (Dec 25, 2012)

> ...exactly how much I would need to dissolve the AgCl in multiple steps as described above.


Dan, AgCl does not dissolve in nitric! You might have to place it in a blender, and proceed to convert with lye and sugar, or go the sulphuric way.
You have missed in your reading some important points when it comes to refining silver safely and efficiently. Hold on to your AgCl and continue reading...
Take care and be safe!
Phil


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## Palladium (Dec 26, 2012)

If you washed it with ammonium hydroxide chances are you dissolved some and threw it away with the wash water.


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## butcher (Dec 26, 2012)

Washing silver chloride in ammonia will dissolve the silver chloride, and form an amine complex of silver, this could create a dangerous mix if the silver powders contained resuidual ammonia.

Silver diammine Ag(NH3)2, when dry this is dangerous, a temperature and shock sensitive compound, acidifying with acid destroys the complex and precipitates back the silver chloride.

Silver chloride will not dissolve in HNO3 (silver metal will).

Some of the silver chloride could have converted to silver by light.

Putting this silver in a blender and making it into a fine powder with wetting will help, you need every crystal seperated if possible to react.

There are several methods to convert the silver chloride to metal. 

Sodium hydroxide NaOH (caustic soda, lye) and Karo syrup C6H12O6 (dextrose, sugar).

GSP gave a formula for silver chloride conversion:
31.1g AgCl
15g NaOH
100ml H2O
10ml Karo syrup

2AgCl + 3NaOH + C6H12O6 --> 2Ag + 2NaCl + C6H11O7 + H2O

Dilute sulfuric acid and Iron metal, to convert silver chloride to metal:
2AgCl + H2SO4 + H2O + 2Fe --> 2Ag + FeCl2 + FeSO4 + H2(g) + H2O

HCl and aluminum metal to convert the silver chloride to metal powders:
AgCl + HCl + H2O + Al --> Ag + AlCl2 + H2O + H2(g)

(Formulas not checked for balance).

The other option which I do not like is flux melting, the sodium carbonate in the flux (eats up the melting dishes).


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## Bushka (Dec 26, 2012)

philddreamer said:


> > ...exactly how much I would need to dissolve the AgCl in multiple steps as described above.
> 
> 
> Dan, AgCl does not dissolve in nitric!
> Phil



Hi Phil. Yes, I understand that. What I meant in step 3 when I say "until all the AgCl is processed" is that I could dissolve the trace silver in the AgCl plus any silver converted from AgCl through lye and syrup. Then I would only have AgCl left over. I would then process the AgCl again with lye and syrup, and then with nitric to dissolve any silver formed (thus separating it from the AgCl). I would continue this until all the AgCl was converted to silver. Maybe if I used a blender and took a long time with it, this could be done in one step, maybe...


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## Bushka (Dec 26, 2012)

Palladium said:


> If you washed it with ammonium hydroxide chances are you dissolved some and threw it away with the wash water.



I saved all wash water and either hit it with copper pipe or precipitated out AgCl with salt and/or HCl. I didn't throw anything away. I do have a slop bucket of mostly HCl wash water that I believe has no Ag or AgCl left in it.

Thanks!


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## Bushka (Dec 26, 2012)

butcher said:


> Washing silver chloride in ammonia will dissolve the silver chloride, and form an amine complex of silver, this could create a dangerous mix if the silver powders contained resuidual ammonia.
> 
> ...



Thanks for the thorough reply, butcher. I am aware of the dangers of using ammonia. I got away from that anyway because it didn't dissolve enough to be practical.

I was thinking about using the blender method, but I will have to destroy a blender probably, plus I was concerned that the gasket might leak if it gets very hot.

Do you have a preferred method for converting the AgCl, or would any do fine? I kind of like the lye method because the reagents are cheap, plus you provided a detailed formula.


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## butcher (Dec 26, 2012)

An old blender from a second hand store will hold up fairly well.

You could grind the powder dry with a mortor and pestle, I would the screen (plastic screen) it for clumps to return lumps to the mortor to regrind.

Fine powder without clumps is important to getting the silver crystals exposed, in either of the conversion methods, in the acid and metal (electron replacement reaction) contact of the silver chloride is important for electron exchange, or to get the chloride to form salt water with the NaOH and oxidize the silver, the lumps of silver chloride seem to not get converted inside the lump, the finer the silver crystals the better the mixing and stirring, the better the conversion process works.


I like either the NaOH Karo method, or the iron and dilute sulfuric acid method, they both work well (I do not like dealing with aluminum waste) so I do not have expierience with it much at all ,but it should also work well.

Actually I just do not like dealing with silver chloride if I can help it.


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## Bushka (Dec 26, 2012)

butcher said:


> An old blender from a second hand store will hold up fairly well.
> 
> You could grind the powder dry with a mortor and pestle, I would the screen (plastic screen) it for clumps to return lumps to the mortor to regrind.
> 
> ...



The boss gave me approval to use our blender. It appears she was getting a new one anyway. Like I said, I tried to make due with a hammer and a plastic trash liner as I don't have a mortar and pestle. It actually worked reasonably well.

In the recipe you provided, you show 15 g NaOH. I assume this is solid crystalline NaOH to which 100 ml water is added? I'd like to ask some more questions about the recipe, but I wonder if there is a link to that discussion so that I don't repeat questions that have probably already been answered.

Also, this forum does not appear to have an "instant email notification" option. Am I missing something? I find that feature to be almost necessary in order to keep any sort of timely back and forth going.

Thanks,
Dan


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## butcher (Dec 27, 2012)

http://www.google.com/search?hl=en&as_q=silver+chloride+conversion+&num=1000&ft=i&as_sitesearch=goldrefiningforum.com&as_qdr=all&as_occt=any

http://www.google.com/search?hl=en&as_q=silver+chloride+conversion+31.1+g+AgCl+&num=1000&ft=i&as_sitesearch=goldrefiningforum.com&as_qdr=all&as_occt=any

I have seen GSP's recipe all over the internet, I recognize it as his when see others using his recipee, he has made so many posts, and sometime he will use a little different numbers, I just did a little search and came up with these If you do not find it here try searching other keywords, he has made so many posts on this it should be easy to find what your looking for.

GSP also has a great book on CD, lots of information from his many years of refining, I think Laser Steve’s web site may still has it listed, also Laser Steve’s web site search for the forum works better than the search on the forum.


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## Bushka (Dec 27, 2012)

butcher said:


> http://www.google.com/search?hl=en&as_q=silver+chloride+conversion+&num=1000&ft=i&as_sitesearch=goldrefiningforum.com&as_qdr=all&as_occt=any
> 
> http://www.google.com/search?hl=en&as_q=silver+chloride+conversion+31.1+g+AgCl+&num=1000&ft=i&as_sitesearch=goldrefiningforum.com&as_qdr=all&as_occt=any
> 
> ...



OK, great! I'll spend some time and look through these links.

Regards,
Dan


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## Bushka (Dec 29, 2012)

I was watching one of lazersteve's videos on processing AgCl in lye and karo. I noticed that he seemed to have some large chunks of dry AgCl that he broke up by hand. My AgCl has been pulverized for the most part, but there are some small chunks that were small enough to go through a strainer. It makes me wonder if it really is that difficult to process the AgCl if you give it enough time. I also watched the sulfuric acid/iron video and had a question. If time isn't an issue, will the sulfuric method convert the chunks of AgCl better than the lye method? In the video it looked like the longer he left the steel rod in the powder, the more the silver conversion spread throughout the beaker. I'm wondering if the conversion will occur throughout a chunk of AgCl given enough time. Since I'm only processing one batch for now, I don't care if it takes a week.

Also, where's the best place to purchase lye and nitric acid in the eastern US?


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## butcher (Dec 30, 2012)

Maybe GSP will give us some wisdom here, as he has probably dealt with more silver chloride than I will see in my lifetime.

With iron and sulfuric it is an electron exchange, so the more silver chloride that comes into contact with the iron the better the conversion, I would stir often and crush clumps as much as possible.
surface area of the iron can also come into play.

The better you have the clumps crushed the more silver you will convert, silver chloride in a melt is volatile or will not melt well, so what you do not get converted may not melt back to metal.
I find even silver chloride that was never dried can have clumps that if are not crushed will not melt (here is where that blender and screen come in handy.

Hopefully someone on the east side of USA can help you with the chemicals.


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## Bushka (Dec 31, 2012)

butcher said:


> Maybe GSP will give us some wisdom here, as he has probably dealt with more silver chloride than I will see in my lifetime.
> 
> With iron and sulfuric it is an electron exchange, so the more silver chloride that comes into contact with the iron the better the conversion, I would stir often and crush clumps as much as possible.
> surface area of the iron can also come into play.
> ...



Thanks Butcher. Maybe Steve will post a reply as well. In his video he was breaking up large chunks by hand, and he seemed to get full conversion. My chunks are tiny in comparison.


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