# Help with Silver Refining



## Jackhopper09 (Jul 26, 2011)

Hi, I have been scouring the silver section of the forum, and I have a question for the experts. I am one of the biggest beginners ever on the history of the site, but I will admit I have learned a huge amount of information from all of you and I thank you all for that, especially nickvc, lazersteve, and Harold_V. Now my question. Is refining silver in a cell avoidable? From reading, I'm pretty sure refining by nitric acid makes a 98% or so fineness. Now refining by nitric acid is something that sounds a lot easier than a silver cell, and the silver cell is only to achieve a very very slightly finer silver. Is it necessary to refine by a silver cell or could you put the 98% silver back in nitric acid and repeat that process? Would it reveal a 99% silver cement or will it remain 98% or lower? If that is something you can't do, and you have to refine by a silver cell, do you make your own silver nitrate by dissolving pure silver in nitric acid, or do you buy it? Is the silver in the silver nitrate recoverable? Does the silver in the silver nitrate contribute to the crystals that are grown? This is a learning experience for me, so please tell me if I have a close idea or if I have missed it completely. Don't be overly critical, but if some criticism is needed to help me learn, by all means lay it on me.

Jack


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## goldenchild (Jul 26, 2011)

Jack,

You can certainly avoid the silver cell and get more than satisfactory results. My highest purity to date is .9994 using the silver chloride method. Keep in mind this was the very first time I ever refined silver in an appreciable quantity for the purpose of selling. So I'm confident in saying .9999 is achievable without a silver cell. 

When speaking in terms of silver .999 is acceptable. I'm not sure there is an overwhelming need for .9999 in any industry. I'm not even sure you would get a bonus for that last nine at a refinery like you would for gold. Even then we're talking about bringing in way more than most of us will ever accumulate at one time.


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## Jackhopper09 (Jul 26, 2011)

Thanks for the help, but I don't know what the silver chloride method is. I have so many things I am trying to remember right now, it is hard to know them all. Please respond, I need your help. By the way, I'm pretty sure you're metalicmario on YouTube, my username is SlowinTheMotion, I commented on your channel a few months ago, and I just made the connection.

Jack


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## philddreamer (Jul 26, 2011)

Jack, I, like Mario, use the silver chloride method. If you don't have Lazersteve's video on silver refining I recommend you get a copy. It help me.
There's also plenty of information in the SILVER section.

You would start with 50/50 distilled water/nitric. 
Incinarate your silver; digest silver in acid with heat. After all reaction stops, let cool a bit.
Then you can add table salt (without iodine) or HCl, to precipitate the silver. That "cottage cheese" is silver chloride.
Rinse it good until the water is clear. I like rinsing with hot water a couple of times.
Then cover with cold water, add Lye until the agcl turns dark brown/black. That's silver oxide (elemental silver). CAUTION! Solution will get hot!
After it turns black, add sugar; this will turn the silver into metallic silver. CAUTION! SOLUTION WILL TURN VERY HOT. ADD SUGAR SLOWLY.
Rinse with plenty of water; one rinse with HCl; water again.
Dry & melt.

This is a general description, so to give you an idea. 
Again, do a search & get the whole info in the series of post on refining silver & safety.

Later, you can try the cell if you want to. I'm setting to give it a try myself soon.

Take care!

Phil


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## goldsilverpro (Jul 26, 2011)

Goldenchild,

What analysis method was used to determine that your silver was 999.4 Fine?


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## Jackhopper09 (Jul 26, 2011)

I appreciate that so much Phil, that was the push I needed to get going down the mountain. I appreciate all of everyone's time and patience with the newbies! Thanks


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## goldenchild (Jul 27, 2011)

goldsilverpro said:


> Goldenchild,
> 
> What analysis method was used to determine that your silver was 999.4 Fine?




XRF scanned on mutilple surfaces.


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## goldsilverpro (Jul 27, 2011)

I notice that the published error could be as much as .12%. That could lower the purity to 99.84%. That seems a LITTLE more realistic to me for refining AgCl, but I just don't trust XRF at that purity level. The best method is to analyze for all the impurities using ICP, add them all together, and subtract from 100.


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## 4metals (Jul 27, 2011)

In the overall scheme of things, the silver chloride conversion process takes a huge quantity of rinse water to get the requisite purity. If you are any kind of commercial operation the resulting waste treatment can be a bear. That is the beauty of electrolytic processing, much less waste. If you are doing a nitric digest to get rid of most of the base metals, your cement silver should be 99% and a silver cell will work long and hard for you with that feed stock. Plus the results are more predictable from a cell.


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## goldsilverpro (Jul 27, 2011)

4metals said:


> In the overall scheme of things, the silver chloride conversion process takes a huge quantity of rinse water to get the requisite purity. If you are any kind of commercial operation the resulting waste treatment can be a bear. That is the beauty of electrolytic processing, much less waste. If you are doing a nitric digest to get rid of most of the base metals, your cement silver should be 99% and a silver cell will work long and hard for you with that feed stock. Plus the results are more predictable from a cell.



I agree. From my experience, AgCl is one of the most difficult substances to filter and rinse on the planet, especially if you have a lot of it. That's mainly why I questioned the 999.4 purity. AgCl will stop a vacuum filter in no time. In order to get any speed at all through a filter, I used to dissolve extra silver, add Cl to produce fresh AgCl from it, immediately put it in the vacuum filter, and put the AgCl I was originally trying to filter on top. In other words, I had to use fresh AgCl as a filter aid to filter AgCl. Even then, it would take an entire day, literally, to filter and rinse, and it still wasn't that super clean.

That's only the AgCl. Then you have the converted silver to filter and rinse.

Unless you have pure silver to start with, I think you're fooling yourself to think you have 99.94% Ag converted from the AgCl. No offense but, I just don't believe a word of it.


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## goldenchild (Jul 28, 2011)

goldsilverpro said:


> Unless you have pure silver to start with, I think you're fooling yourself to think you have 99.94% Ag converted from the AgCl. No offense but, I just don't believe a word of it.



GSP, 

Do you believe this refinery is calibrating their xrf to analyze to a higher purity? I know of no place on earth that would do that. And surely they would rectify it in a hurry. It's possible to get 4 nines from wet refining gold so why not silver? 

There is a post somewhere where I talk about getting rid of all the nitric in silver before a melt. It's something to the tune that I pretty much try to avoid using filters to get the nitric all out. I follow the same procedure when dealing with AgCl. Whether the purity was truly 99.94 or 99.84 the bottom line is that I got paid for 99.94.


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## goldsilverpro (Jul 28, 2011)

goldenchild said:


> goldsilverpro said:
> 
> 
> > Unless you have pure silver to start with, I think you're fooling yourself to think you have 99.94% Ag converted from the AgCl. No offense but, I just don't believe a word of it.
> ...



I would have to ask what your starting material was and how much you had of it. I never produced AgCl unless I had to and, when I did, I usually worked with large amounts. I once had a job that contained many 1000s of oz of silver, in the form of silver braze containing a fair amount of copper (but no Pd). After using nitric to dissolve the braze and filtering this solution, I was forced to produce AgCl, but I won't take the time to go into the reason why. I had a 24" vacuum filter, about 12" high, and it was filled to the brim many times with AgCl. The material was rinsed until the addition of some ammonia to a sample of the rinse water coming through the filter showed no blue color against a piece of white paper. The clean AgCl was immediately put into a large plastic vat wet with a big Lightin' mixer and the AgCl was converted to Ag metal with NaOH/formaldehyde (carcinogenic), which, to me, is the cleanest conversion method I have every used. Small samples were taken, rinsed with distilled water, dissolved with dilute nitric, and examined for any AgCl residue, to make sure it was all converted. The moral of this story is that the Ag produced was only 99+% and still had to be run through a silver cell. I had enough silver cells to produce about 5000 oz/day, so this went fast.

In thinking this over, while working with small quantities (say, 25 oz, more or less), it would be easy to produce, in a lab, high purity silver (probably even 999.9 Fine), chemically, from AgCl. You don't have to worry about generating a lot of waste water and can rinse with hot water to your heart's content, whether by decantation or by filtration (or, both). You can afford to dissolve the AgCl in ammonia and reprecipitate it with HCl. You can do everything a second time, if you wish. I can think of other things that could be done, like specific leaches and rinsing it a container with a chopper-type mixer. However, with large quantities, it's a different ball game and you must think about costs and the time that it takes. You've got to turn the metal ASAP. In an industrial situation, it's not whether you can do it, but can you afford to do it and is it necessary to do it?


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## goldenchild (Jul 28, 2011)

goldsilverpro said:


> I would have to ask what your starting material was and how much you had of it.



If I remember correctly I ended up with 908 grams of pure silver. The source material was sterling jewelry. So I'm guessing I processed just shy of 1 kilo of jewelry.



goldsilverpro said:


> The moral of this story is that the Ag produced was only 99+% and still had to be run through a silver cell. I had enough silver cells to produce about 5000 oz/day, so this went fast.



Yes sir. If I was set up for this and got a steady flow of scrap I would surely quit my day job 8) 



goldsilverpro said:


> In thinking this over, while working with small quantities (say, 25 oz, more or less), it would be easy to produce, in a lab, high purity silver (probably even 999.9 Fine), chemically, from AgCl. You don't have to worry about generating a lot of waste water and can rinse with hot water to your heart's content, whether by decantation or by filtration (or, both). You can afford to dissolve the AgCl in ammonia and reprecipitate it with HCl. You can do everything a second time, if you wish. I can think of other things that could be done, like specific leaches and rinsing it a container with a chopper-type mixer. However, with large quantities, it's a different ball game and you must think about costs and the time that it takes. You've got to turn the metal ASAP. In an industrial situation, it's not whether you can do it, but can you afford to do it and is it necessary to do it?



I've mentioned in another post that for most of us on the forum (me included) it's difficult to think of our processes on a larger scale. We are so used to processing such small quantities that this train of thought comes naturally. I suppose that for someone with your background it may be the inverse. I know Harold won't be happy with this (and I'm not promoting it) but... take for instance inquartation. On a large scale it wouldn't be feasible for a few reasons. But for the home refiner to small scale refiner it's an excellent technique.


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## goldsilverpro (Jul 28, 2011)

> I've mentioned in another post that for most of us on the forum (me included) it's difficult to think of our processes on a larger scale. We are so used to processing such small quantities that this train of thought comes naturally. I suppose that for someone with your background it may be the inverse. I know Harold won't be happy with this (and I'm not promoting it) but... take for instance inquartation. On a large scale it wouldn't be feasible for a few reasons. But for the home refiner to small scale refiner it's an excellent technique.



You're right. It is hard for me to think of small quantities, especially with silver. I know it has hampered my communications with other members and our recent discussion is a good example. I do apologize. After I thought about it, I realized that we were essentially talking about different requirements. Even though it was all silver, it was apples and oranges, if you may.

I'm not going to get into the inquartation thing.


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## shgrunewald (Sep 23, 2011)

There is always a depreciation factor when using chemicals to refine silver especially with nitric acid. Once refined, try refining again and you will see what I mean. It is even true with manufacturing.


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