# AgCl to Ag+AlCl3



## David Frederick (Apr 19, 2022)

I’m trying to figure out an effective way to chemically separate Ag from AgCl. Currently I’m experimenting with aluminum. I’m running into an issue with the Ag forming a shell around around untreated AgCl. This is how the boss wants it done but I’m struggling to make it work. 
The current process is removing Ag from nitric acid using HCl, rinsing and collecting the AgCl. Placing 50lbs of the AgCl into a cement mixer and adding water. Once blended slowly adding fine aluminum until roughly 2.5 pounds has been added, always keeping the temperature below 120 F. If anyone has any tips, tricks, or completely new processes I’m open to all suggestions.


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## Martijn (Apr 19, 2022)

Welcome to the forum. 
Agitation is key imo. Try a sharp blade stirrer to cut it all up in the solution. 

Have you considered not converting to AgCl and cementing AgNO3 directly on copper? Or the lye and sugar conversion.
Martijn.


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## snail (Apr 19, 2022)

A method that has received considerable comment here is to use dilute Sulfuric (about 10%) in a cement mixer with heavy iron punchings or short pieces of rebar.

The pieces of iron help break down the pieces of silver chloride. Iron contamination tends to not alloy into the silver when melting.


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## Lino1406 (Apr 19, 2022)

Aluminum has a major drawback, producing aluminum oxide which is hard to get rid of


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## David Frederick (Apr 19, 2022)

Martijn said:


> Welcome to the forum.
> Agitation is key imo. Try a sharp blade stirrer to cut it all up in the solution.
> 
> Have you considered not converting to AgCl and cementing AgNO3 directly on copper? Or the lye and sugar conversion.
> Martijn.


I just did a small sample of the lye and sugar method and it came out really well. About 99.2%, but I’m getting resistance from the boss since we’ve never done it that way before. 
I have not tried the silver nitrate method…would you elaborate on that please? I know nothing about it.


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## David Frederick (Apr 19, 2022)

snail said:


> A method that has received considerable comment here is to use dilute Sulfuric (about 10%) in a cement mixer with heavy iron punchings or short pieces of rebar.
> 
> The pieces of iron help break down the pieces of silver chloride. Iron contamination tends to not alloy into the silver when melting.


The sulfuric and iron method is how we originally processed Ag and I think we may need to go back to that.


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## Alondro (Apr 19, 2022)

David Frederick said:


> I just did a small sample of the lye and sugar method and it came out really well. About 99.2%, but I’m getting resistance from the boss since we’ve never done it that way before.
> I have not tried the silver nitrate method…would you elaborate on that please? I know nothing about it.


The lye + sugar method works phenomenally and is cheap. When the lye is added, warm and agitate it until the powder looks evenly dark brown-black and is only small particles. Clumps that don't stir apart still could have a core of AgCl remaining unconverted. You can use Karo corn syrup for the sugar, which is high-dextrose, the ideal reducing sugar, and very cheap to buy in bulk.

There are no other metal in those reagents, so the only contaminants after the completed reduction and washes will be those found in the AgCl itself.


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## Martijn (Apr 19, 2022)

You have silver nitrate. 
When you make the nitrate, leaving a piece of silver undigested, using up all excess free nitric, filter and put a piece of clean copper in the solution. 
Silver will be displaced from solution as metallic silver, trading electrons with the copper, which goes in solution. The silver can be washed and melted. 
Basically the same as: 









When In Doubt, Cement It Out


When In Doubt, Cement It Out This is advice I often give to new members who find they've created a bit of a mess, and they're wondering how to recover their values (gold, silver, PGMs, etc.). Perhaps they've followed a process they've seen on YouTube that left out some important details...




goldrefiningforum.com




Based on the reactivity series. 

This can result in 99% pure silver or better. 
Further refining can be done in the electroytic silver cell. 
You will be left with copper nitrate with traces of silver, get that last bit out with HCl. 

Martijn.


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## David Frederick (Apr 19, 2022)

I appreciate everyones feedback, I think I’ve got enough information to move forward anyway. I’ve got about 3300 lbs of AgCl to process, but I may come back to you all if I can’t get ratios right or have any other questions. Thank you again!


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## Alondro (Apr 20, 2022)

David Frederick said:


> I appreciate everyones feedback, I think I’ve got enough information to move forward anyway. I’ve got about 3300 lbs of AgCl to process, but I may come back to you all if I can’t get ratios right or have any other questions. Thank you again!


Ah, you're doing true industrial scale refining. Yes, the NaOH and sugar method will work best for such quantities. With any method using a metal to displace the silver from the chlorine, you risk heavy contamination unless it's a process you're innately familiar with and know all the little crucial details to make it work. 

You'll be buying bulk amounts of lye and sugar, which will make those reagents even cheaper per pound than for those of us who just buy a bottle of lye and a bag of sugar/bottle of corn syrup from the store for our few ounces or pounds of silver.


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## snoman701 (Apr 20, 2022)

Are you using a plastic tub cement mixer? I don't understand why the sulfuric iron method was abandoned. 

It's the easiest by far, my biggest issue is the filtration. It's a lot of work.


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## David Frederick (Apr 21, 2022)

snoman701 said:


> Are you using a plastic tub cement mixer? I don't understand why the sulfuric iron method was abandoned.
> 
> It's the easiest by far, my biggest issue is the filtration. It's a lot of work.


I am using a plastic tub cement mixer. Even though the sulfuric and iron method was working for us, my boss is a chemist. We had a ready source of Al and according to his calculations the Al would have been more efficient and save some time. I was having a lot of trouble getting it to work so I got desperate and came here for wisdom.


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## David Frederick (Apr 21, 2022)

Alondro said:


> Ah, you're doing true industrial scale refining. Yes, the NaOH and sugar method will work best for such quantities. With any method using a metal to displace the silver from the chlorine, you risk heavy contamination unless it's a process you're innately familiar with and know all the little crucial details to make it work.
> 
> You'll be buying bulk amounts of lye and sugar, which will make those reagents even cheaper per pound than for those of us who just buy a bottle of lye and a bag of sugar/bottle of corn syrup from the store for our few ounces or pounds of silver.


To make sure I understand what I’m doing with the lye and sugar: I would need to add the AgCl and water, then the lye until I bring the Ph back to neutral then add the sugar until there is no more reaction, rinse and be done? 
I did a very small sample in a five gallon bucket, but I think I added to much caustic soda because the silver turned black, but it was still 99.2% so I didn’t think much of it.


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## Alondro (Apr 21, 2022)

David Frederick said:


> To make sure I understand what I’m doing with the lye and sugar: I would need to add the AgCl and water, then the lye until I bring the Ph back to neutral then add the sugar until there is no more reaction, rinse and be done?
> I did a very small sample in a five gallon bucket, but I think I added to much caustic soda because the silver turned black, but it was still 99.2% so I didn’t think much of it.


Silver chloride is supposed to turn black when lye is added and mixed up well, because it's turning into silver oxide. That's step 1. Then it needs a wash to remove the bulk of the lye, and then add the sugar and mix more. After a little while, it should turn light silvery-grey. That's the reduced and very pure silver.


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## David Frederick (Apr 21, 2022)

Perfect! So my attempt is about half right, I need to rinse it, mix it up well, and then add the sugar. With that being said, if I were to melt the silver oxide would it just burn the oxygen out leaving me with metallic silver? I’m trying to learn this stuff on the fly so I really appreciate all of this information!


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## silver1 (Apr 21, 2022)

David Frederick said:


> Perfect! So my attempt is about half right, I need to rinse it, mix it up well, and then add the sugar. With that being said, if I were to melt the silver oxide would it just burn the oxygen out leaving me with metallic silver? I’m trying to learn this stuff on the fly so I really appreciate all of this information!


Add the _NaOH_ and sugar together. No need to wash the _NaOH_ away before sugar addition. This will lead to more problems. The NaOH helps break down the sugar. Yes you can melt the silver ox straight, but washing and filtering can be a p.i.t.a.. Sugar is cheap and completes the process.


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## silver1 (Apr 21, 2022)

Conversion of AgCl via NaOH and Karo Question


I tried the method for reducing silver chloride using sodium hydroxide and sugar. I really like how fast it works. I would like to understand the process more. I know that sodium exchanges the hydroxide ion for the chloride ion and the silver takes an oxygen molecule to form sodium chloride...




goldrefiningforum.com


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## snoman701 (Apr 21, 2022)

I feel like NaOH and Karo syrup at that scale is just ASKING for an ant infestation!


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## Alondro (Apr 21, 2022)

snoman701 said:


> I feel like NaOH and Karo syrup at that scale is just ASKING for an ant infestation!


Eh, we get swarms of those Argentine ants everywhere even without it. We have BILLIONS of them hiding under every rock, inside every pipe, under bark, under siding, in mailboxes, under leaves... basically any sheltered space with a little slit for an entrance is full of the damned things. 

I actually use a mix of sugar and borax to at least keep the ones that come pouring into the house in spring under control.


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## David Frederick (Apr 22, 2022)

I’m taking it really slow while adding sugar (I only have granulated sugar from the break room because I’ve been told to stop but I’m not giving up on it lol) and I am starting to see the silver in the bottom. Would you happen to have a good starting ratio so when I try a larger batch next time I’m a little closer to my goal? I’m also using caustic soda because I don’t have any dry lye, will that make any difference?


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## kurtak (Apr 22, 2022)

David Frederick said:


> I’ve got about 3300 lbs of AgCl to process


Trust me - with that much AgCl you DO NOT want to use the lye/sugar method !!! (you can ask me why & I will be glad to explain why)

*Hands down & without question* - with that much AgCl - the BEST method (& answer) is to go back to the iron/acid/cement mixer method (though zinc could be used in place of iron)

You need to tell your boss that - though "on paper" aluminum "should" work - so we have tried that - BUT - we have run into problems with that --- so I went in search of why aluminum is giving us problems 

In my search the answer to that problem is ------ (so what Lino said)



Lino1406 said:


> Aluminum has a major drawback, producing aluminum oxide which is hard to get rid of


you need to further tell your boss that this advice is coming from some LARGE scale refiners that work with this stuff EVERYDAY

Tell him (your boss) that based on advice from these "actual" refiners - we need to go back to the iron/acid/cement mixer method - as the BEST method for that much AgCl

I believe that Lou (*who "runs" 4 "large" scale refineries*) will back me up on this

Kurt


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## kurtak (Apr 22, 2022)

David Frederick said:


> I’m getting resistance from the boss





David Frederick said:


> (I only have granulated sugar from the break room because I’ve been told to stop but I’m not giving up on it lol)





David Frederick said:


> my boss is a chemist.


You need to tell him - we have two options - we can continue with a process we "think should" work (aluminum) but isn't working --- or - we can follow the advice of refiners that do this every day for a living 

*go back to the iron/acid/cement mixer method*

Kurt


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## snail (Apr 22, 2022)

Search for posts from goldsilverpro. Unfortunately he has passed away, he posted much info on the sodium hydroxide sugar method. 

If you search for posts with silver chloride authored by him you will find the best information.

He used at one point a 50 gal drum with a lightning mixer to convert.

Gives amounts per oz of silver.


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## Shark (Apr 22, 2022)

I have never worked on as large scale as Kurt and many others but after playing around a bit I would never recommend the lye/sugar method. Iron and sulfuric is a very good way to go for many reasons of which much has already been posted. Unless you have very clean silver chloride use the iron/sulfuric you will be save a lot of headaches.


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## galenrog (Apr 22, 2022)

Both methods are great choices for converting silver chloride. Each has advantages and disadvantages. All has been covered on this forum many times.

It is to the benefit of any refiner calling himself a professional to be intimately familiar with both. Doing so allows the best choice for circumstances at hand.

Both methods require experience and expertise.

Forget using aluminum. More trouble than it is worth. For experience, however, perform a few small scale experiments to demonstrate the pitfalls.

Enjoy.

Time for more coffee.


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## silver1 (Apr 22, 2022)

I do anywhere from 600-800 lbs per month average ...... all sugar processed.


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## orvi (Apr 22, 2022)

When we are talking about *3000lbs of AgCl, most economical method will certainly be Fe/H2SO4*, that is for sure. 
I don´t know how and where you obtained so much silver chloride, but if made in your facility, I will seriously think about other methods. AgCl making is nice and easy, but converting it back to silver isn´t that straightforward. Purity required is key to answer here - if you will be happy with 98%, stick copper bar to the filtered AgNO3 solution and agitate. You will obtain nicely settling silver cement, which is easy to filter from the junk. 
Sticking a iron bar into the filtered solution will recover the copper. 
If you are aiming on higher purity, take this silver and electrorefine it.

Lye/sugar method is also cheap to proceed, but it requires vessel with overhead stirrer, or blender-like vessel to stir and break the precipitate simultaneously. I learned when doing this, there is no need to add every reagent at once. You can do it in controlled way to prevent any runaway.
Conversion of AgCl to silver oxide require some heating, but it can be done in few hours, or even less time, if agitation is strong. Then, you will need thermometer to be present in the mixture and adding the syrup (I use crystal sugar) slowly, and watching the temperature rise. If it climbs too high, stop adding syrup and left it cool down for another addition. When temperature stop rising after addition, reaction is done.
I can imagine this to be scaled up to tens of kilograms at once. With proper equipment, of course.

But all big guys are using Fe/H2SO4 or direct smelting methods.


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## Shark (Apr 22, 2022)

I found the post that made me think the way I do but don’t know how to link it from my phone. I will try again when I get home this evening. I will say galenrog is right about knowing both methods. The way he said it is more along the lines of what I was thinking. Basically if you have a “dirty” silver chloride use the iron/ sulfuric method but if your working with a fairly clean silver chloride use the lye/sugar method.


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## Alondro (Apr 22, 2022)

David Frederick said:


> I’m taking it really slow while adding sugar (I only have granulated sugar from the break room because I’ve been told to stop but I’m not giving up on it lol) and I am starting to see the silver in the bottom. Would you happen to have a good starting ratio so when I try a larger batch next time I’m a little closer to my goal? I’m also using caustic soda because I don’t have any dry lye, will that make any difference?


I actually use a concentrated liquid lye/caustic soda since I warm and mix the silver oxide to make sure all the chloride is converted. 

I've made 6 ounces of silver, one ounce at a time, adjusting the method to get the best result.

You can overload it with sugar. Basically, you can't add too much. You just end up wasting sugar once the silver is reduced, that's all.


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## Alondro (Apr 22, 2022)

orvi said:


> When we are talking about *3000lbs of AgCl, most economical method will certainly be Fe/H2SO4*, that is for sure.
> I don´t know how and where you obtained so much silver chloride, but if made in your facility, I will seriously think about other methods. AgCl making is nice and easy, but converting it back to silver isn´t that straightforward. Purity required is key to answer here - if you will be happy with 98%, stick copper bar to the filtered AgNO3 solution and agitate. You will obtain nicely settling silver cement, which is easy to filter from the junk.
> Sticking a iron bar into the filtered solution will recover the copper.
> If you are aiming on higher purity, take this silver and electrorefine it.
> ...


I've seen a couple people directly smelt silver chloride. Does that actually work well? I had thought it would melt and some would vaporize before reducing, leading to loss. Does a carbon source need to be added?


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## Shark (Apr 22, 2022)

Anyone remember the old E.F. Hutton commercials? Here is all it took for me to decide to go a certain way....









Converted Silver Chloride


I have started working on some silver lately and have been a bit surprised with some of the results. Here is a button (?) that I converted from silver chloride using iron and sulfuric acid. I done this as a test to see how difficult it might be and and to compare it with the lye/karo process. I...




goldrefiningforum.com


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