# Refining silver without nitric



## Anonymous

Hey all

This is my first post so please bear with me if the question has been asked before

I plan on starting buying up scrap silver (probably jewlery since I don't have room for large quantities of stuff containing small amounts of silver)

I have access to casting equipment but I would like to know a little bit more about the refining process before I begin

As far as I can tell everyone refines silver using nitric acid and then further refining the silver nitrate. though if you watch this video http://www.youtube.com/watch?v=zdu5yS5q2so it seems that they are using a process similar to electroplating when removing the silver from the gold. (or is the liquid the metal is submerged into really some sort of acid solution?)

Is it possible to make some sort of setup using a buchet and a power source to electrically refine sterling silver.

Should I even bother refining the 925 silver, or should I just cast it into bars and sell as 925 silver?

Best regards
Henrik Poulsen


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## Oz

ThePoulsen2 said:


> Should I even bother refining the 925 silver, or should I just cast it into bars and sell as 925 silver?



That depends on your buyer. Will they pay you a premium for .9999 silver over that of scrap sterling? For that matter if you are selling it as scrap sterling, melting it to bar form could be a hindrance instead of a help to your end user. Not to mention your labor cost.


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## goldsilverpro

That video doesn't even begin to tell you the whole story and is very, very simplistic. However, it is obvious what they are doing. 

First, to dissolve the copper only from the Cu/Ag/Au alloy and plate it out, there are using a weak sulfuric plating cell. 

Second, they re-melt the silver and gold, which are both undissolved in the sulfuric. The Ag/Au alloy bars are run through a silver cell, which is made up of weak nitric acid, a little copper nitrate, and a lot of silver nitrate. The silver dissolves and plates out in a crystal form. 

Third, the gold that remains (which is contaminated with silver and other things) is re-melted and run through a gold refining cell (called a Wohlwill cell), containing HCl and gold chloride (actually chloroauric acid). The gold plates out in a pure form and is finally melted. They didn't mention the gold cell.

The silver cell must be set up properly with the right ingredients, under the right conditions. It's not something you can just throw into a bucket, using any old solution, and turn the juice on.

To consider your final question. First of all, how much weight of sterling do you have? Is it all marked as Sterling or 925?


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## Anonymous

Thank you for your replies.

I did have a hunch that the video was an oversimplification of the real process, those "how its made" videos often are

At the moment I don't have any scrap metal, as I am still just researching at the moment. I am currently at university here in denmark and plan on posting a number of flyers advertising that I buy scrap silver (someone is bound to call me at the end of the month when their money runs out  
Another idea I have is to advertise on the danish classified websites (Similar to ebay) that i purchase silver scrap. Naturally I am aware of the possibility that what I buy is stolen goods. for that reason I am currently in contact with my local police station for further information. as far as I know they have a register of stolen jewlery that I can compare with.

at university I have access to a furnace etc. but the refining I would have to do at home, which is not the greatest idea since I would have to do it inside, and I understand that the chemicals used are very toxic. thats why I am considering just melting the 925 sterling into bars (Perhaps even thin the bars into sheets of varoius thicknesses and see if I can sell to a jewler or two in town.)

As you can see I haven't got far in my planning yet. and I don't expect I will do much melting etc untill I have at least one or two pounds of silver available.

Henrik


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## nickvc

Dont melt anything marked Georg Jensen its worth far more as a piece of jewellery than its scrap value.


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## Anonymous

Hehe thats true  being from Denmark I know too well that georg jensen silver is wery pricy.

And of course I will try to sell most of the stuff I recieve as jewlery rather than melting. unless its broken or scrap


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## peter i

Nice to have another Dane around ;-)

(There is a couple of us already)

Be very careful about using the University's furnaces, they are not all very well suited for the task (but very expensive if you break them). Furthermore, using university equipment for "personal commercial projects" could get you in trouble.

Bottom line: You will have to precess a relatively large amount before making real money.


maybe we should take the chit-chat over personal messages?

And just to quote HaroldV from another similar thread:


Harold_V said:


> .............
> If you think you can buy sterling and make a profit, make it your hobby, and don't quit your day job. I refined silver as a service to my customers, due to the fact that it was silver I chose to use for inquartation in my gold refining service. I charged 20% for refining silver, and do not consider myself as having made a profit. This was long ago, when silver was far more available, and at a reduced price as compared to today. I also was paying only $4/gallon for nitric acid.
> 
> Said another way, if you think you can make a few fast bucks dealing with silver, I see a dismal outcome for you. It's just not a cash cow the way you may think it to be.
> 
> Harold


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## Juan Manuel Arcos Frank

God!!!!!!!....A young Danish doing what I did when I was young!!!!!!

Look,Henrik,be careful about what you are dreaming because your dreams colud become true.I do not know anythig about jewelry but you can find an urban silver mine in wastes like electronics,batteries,solder,relays,photo processes and so for.

You can use nitric acid to refine silver,toxic fumes can be trated with sodium hydroxide,you can use the hydrogen peroxide process to avoid fume generation.

I have heard that former Denmark coins contained silver,you can get silver from them.

Kindest regards

Manuel


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## Platdigger

You can't say that here Manuel, you might get banned.


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## Palladium

Next thing you know people will be trying to say the Pledge of Allegiance.


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## Juan Manuel Arcos Frank

Platdigger:

Those coins are no legal tender now,so you can do with them whatever you want.

Have a nice day.

Manuel


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## 4metals

Juan Manuel Arcos Frank said;
You can use nitric acid to refine silver,toxic fumes can be trated with sodium hydroxide,you can use the hydrogen peroxide process to avoid fume generation.


While this is very true, why spend cash on peroxide and sodium hydroxide when you can build a fume scrubber to work in a closed system to recover your nitric and use it over. When you're starting out caustic scrubbing is fine because the equipment is more widely available, but after you're making some money, try the closed system approach, your only consumed chemical is O2 after you're up and running.


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## SilverNitrate

Depending on how good your knowledge of chemistry is, you can use sulfuric acid. silver sulfate has a much lower solubility than the nitrate but not like the chloride, so silver sulfate could be rinsed of the copper solution easily. then you can cement out the dissolved silver solution with solid copper. 
The process will have the strong smell of SO2 which you may want to scrub.


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## Anonymous

Great replies everyone  Can't wait to get going, allthough I have to wait a few months before doing all the chemical experiments. I live in student dorms at the moment which unfourtunately does not come supplied with a massive fume hood  

I have to read up on the chemistry though (Its around ten years ago I had high school chemistry) The first hurdle will be getting hold on the nitric though, here in Denmark only 30% nitric acid is legal to sell or buy (Anti terror laws, gotta hate them) and even that seems to be hard to find. 

If I want to refine old coins that is 50% silver. is it just as simple as adding nitric to the coin untill its fully dissolved, filter the acid, and then just add a copperwire to precipitate the silver out of the solution? 
Or am I missing a few steps, I am having difficulty believing that I can refine 50% silver to around 90-99% using this simple method. Mainly since the other 50% in the coin is probably copper, how then will adding more copper make the silver precipitate? is this because the nitric wants to react with the kopper rater than the silver?

Sincerely
Henrik Poulsen


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## Harold_V

ThePoulsen2 said:


> The first hurdle will be getting hold on the nitric though, here in Denmark only 30% nitric acid is legal to sell or buy (Anti terror laws, gotta hate them) and even that seems to be hard to find.


That will work fine. Just reflect the percentage in the work you do. Also, do remember, when you're working with nitric, dissolving metals, you generally dilute 50/50 anyway, so you'll be close enough that you can just use yours without further dilution.



> If I want to refine old coins that is 50% silver. is it just as simple as adding nitric to the coin untill its fully dissolved, filter the acid, and then just add a copperwire to precipitate the silver out of the solution?


That's all that is required. Because the resulting metal isn't generally considered to be pure, but is, instead, processed further in a silver cell, you don't really have to worry much about other contaminants. That's not to say you should work in a poor fashion, using dirty copper for recovery, for example. 



> how then will adding more copper make the silver precipitate? is this because the nitric wants to react with the kopper rater than the silver?


Cementation is not caused by the presence of copper in solution, it's caused by the elemental copper giving up an electron to the silver in solution, permitting it to revert to elemental silver instead of silver nitrate. Copper is used because it is selective, not reducing any of the base metals. In the process, you will dissolve a corresponding amount of copper, adding yet more copper to the solution. While an abundance of free nitric isn't required, it has been my experience that the solution should contain some free nitric, just not enough to permit the unused nitric to dissolve the copper. If, when you are attempting to cement your silver, you get a brown cloud from the reaction, you likely have too much free nitric. 

I generally don't recommend a person use copper wire. As the silver cements, the wire is slowly consumed, not necessarily uniformly. Assuming you don't have an abundance of silver nitrate, and all the wire that is introduced isn't consumed, you often are left with small bits of copper mixed in the cemented silver, making it very difficult to remove them entirely. That defeats, to some degree, the purpose of dissolving and recovering the silver. If you can melt the wire to form a large piece, I recommend that process, otherwise, if you can obtain pieces of copper (buss bar, for example), you'll be far better served. 

About the dissolving process. Chlorinated water will always generate a trace of silver chloride. I wasn't concerned about the minor traces that were created, finding the convenience of using tap water worth the small loss. If you'd prefer to not lose any as silver chloride, distilled or de-ionized water is desirable. 

Harold


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## Toobigfortx

I Have Roughly 5 Pounds Of Scrap Silver 925 Could I Used The Electrochemical Method And Flake Out .9999 Silver? Or Will The Little Bit Of Copper and Steel(Sorry I Meant Nickel) Get In The Wat Of That?


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## Oz

First off why do you have steel in your sterling?

The short answer to your question here is yes, you can use a silver cell to get .9999 purity from .925 sterling. Having said that, it is far from a slam dunk and you will have a lot of learning curve as to testing for impurities in your final products. 

I have run silver cells for some time and to be on the safe side of things I only guarantee .999 with once run sterling after testing for Pd, Ni, and Cu contamination. I also use distilled water and ACS grade nitric (home brew nitric or technical grade is a bad move for high purity results). To say it is 4N it must be run a second time in a cell. 

This also assumes you know how to properly evaluate your feed stock before it even sees a cell. There are also many things you learn to see with experience as to crystal growth before you could confidently claim a certain level of purity.


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## Toobigfortx

Ok Thanks for The Info. Let Me Just Try And Understand A Few Things First. Check To See If This Is Right. I Will Need Silver Cells, AgNO3, .925 Sterling, Time And Acid Tests For Cu And Ni. Is There Anything Else That I Would Have To Learn , Other Than The Electromotive Series? And That Silver Can Be Grown Between .8 Volts And 4 Volts. Can I Use Just 4 Regular Double A Batteries? Wont That Give Me 3VDC? To My Knowledge That Should Be Enough To Grow The Crystals Pretty Fast. If That Will Not Eliminate The Impurities Then Will I Have To Go With The Nitric Acid Route First Then The Electrochemical Way To Completely Purify?


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## Barren Realms 007

Toobigfortx said:


> Ok Thanks for The Info. Let Me Just Try And Understand A Few Things First. Check To See If This Is Right. I Will Need Silver Cells, AgNO3, .925 Sterling, Time And Acid Tests For Cu And Ni. Is There Anything Else That I Would Have To Learn , Other Than The Electromotive Series? And That Silver Can Be Grown Between .8 Volts And 4 Volts. Can I Use Just 4 Regular Double A Batteries? Wont That Give Me 3VDC? To My Knowledge That Should Be Enough To Grow The Crystals Pretty Fast. If That Will Not Eliminate The Impurities Then Will I Have To Go With The Nitric Acid Route First Then The Electrochemical Way To Completely Purify?



Here is a thread that might help you out.

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=1765


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