How do you refine Sterling Silver into Fine Silver

[Rizingfire]

What is involved in cleaning sterling silver so that it is fine silver? I have quite a bite of sterling silverware and jewelry...and am looking into buying a furnace to melt down my scrap but it would be better if I could get the other metals out to have fine silver instead. I suppose I could just pour sterling silver rounds or ingots but I would rather pour fine silver if at all possible.

I have been reading a lot here but it is really confusing and would be a lot easier if the basic processes were pinned at the top of their respective forums. Thank you for your help in advance.

 

[niteliteone]

Rizingfire,
Good luck trying to find a step by step method of doing almost any process here on the forum.

Here the conversation is like at a family dinner table. While one person is saying something a few others always add things not related to the original conversation. And many times the complete story goes untold.

But to try to help you find your answers. Start with Hoke's book. She has a few chapters on processing silver. Also look in the silver section here on the forum. Find all the posts from "kadriver", he covers most of what is needed along with what you learn from Hoke.

Also "lazersteve" sells a DVD from his website that has most of the information in a "how to" video.

Most people here woll get all the basic knowledge available here and experiment with it then follow what works best for them.

Start with reading these few items and come back with questions on anything you don't understand.

Hope this helps
Tom C.

 

[element47]

Rizing, as niteliteone said, kadriver (search for his posts) has posted some truly excellent pictures and descriptions of his cell setup and the processes he uses to refine sterling to .999

Wanting to do exactly this was the reason I wandered to the forum. http://www.youtube.com/watch?v=kq1W-QdMsWQ <<<---is a very condensed video of the process that I believe conforms with the majority of the opinions of the veterans of this process on this board. By "condensed", I mean "condensed" as far as stating the safety gear required, "condensed" as far as how to safely handle the acids, "condensed" as far as dealing with fumes ....well, many other details. For example, I think his use of batteries for the power supply is goofy, but that aside, the video as a whole is a good encapsulation of the whole process, end to end.

Now the question one should probably ask oneself is "why do I wish to do this"? Fun? Profit? Both? Pure curiosity? And at that point, I believe one should carefully tally the "input labor and materials" and compare that number to the "gain in output over just selling the sterling to another refiner". In my case, and speaking only for myself, I could not justify the effort and expense and risk of carrying out the process "here" eg; in my back yard. And I have maybe 250 lbs of sterling forks & spoons, so I have the raw material, but I am not actively working to buy any more at this juncture. My reason: I believe it is cheaper to just buy assayed standard forms of .999 silver and pay the $1. or $1.29 an ounce over spot (or, in the case of junk coins, spot plus almost nothing) and be done with it. I consider sterling forks a very "unpreferred" form, or, at best, "questionable". It's nice that they are assayed, being stamped STERLING. In the real world, sterling allegedly formulated as .925 silver is more like .915 silver, and the process of getting it to .999, whether you do it or someone else does it, is chock full of all kinds of what I call frictions. A civilian will have a tough time getting more than 80% value from a sterling fork. Meaning, a 46 gram fork, gross weight, will yield about 36.8 grams of .999. If YOU get more, it is because YOU paid for chemicals. if YOU can handle kilos and kilos of sterling, then your chem costs will obviously go down. More power to you.

This, then, is all I am trying to say: If you are smart enough to carry out the processes successfully and safely, you should be smart enough to determine whether it is worth it, economically. Me: I couldn't get there.

 

[nickvc]

Element makes some very good points, many on the forum refine as a hobby and if you can source material very cheaply or free as in e scrap or points then refining is the way to go even if you only go as far as dissolving and recovering. I personally can't see the point of refining if I can't get more for the material but then again I have access to cheap fast assays but for those who don't then yes refining makes sense as you know exactly what your selling or hoarding. If you want a hobby and the costs are not important then it's a fascinating hobby that will take years to come to a decent understanding of many of the processes and reactions and with the possibility that you might just find a good profitable source to supplement your regular income or even form the basis of a business. The information you need to make your own decision is here on the forum and with full details you just need to read and study to come to a conclusion of what's right for you.
With regards to sterling silver here in the UK unsoldered hallmarked silver,forks,spoons, salvers castings etc, will be 925 but if it has been soldered it will as Element said be more likely be 915. I'm not sure how much variation to actual assay is allowable elsewhere but the UK rules are very strict.

 

[Rizingfire]

I was just curious because I have about 30-50lbs of silverware. Some is solid, some plated and some that thicker plated stuff that I can't remember the name for...so it was merely out of wanting to turn it into usable round form. I have been stockpiling silver rounds and bars for a while and just figured since I have all this scrap silverware that I got from my grandmothers house after she died that I could make some use of it. I just ordered HCL, SMB and Nitric Acid and hopefully the pound of sim cards I have will yield something decent...not expecting oz but I would be happy with a gram...I have access to as many computers as I am willing to take apart and rip stuff out of so I figured I would like to get into this for a cool hobby as well to maybe add to my stockpile of pm's...and since the boards and stuff are replenished every week it would pretty much be a never ending supply of stuff to strip...since it's just getting trashed anyway I figure why not...I wish I would have known about this when a local PD got rid of all their computers from the 80's...hard to believe the were still using them until several years ago. thanks for the help.

 

[goldsilverpro]

Forget about the silver plate. If I had a semi-load of it - 40,000#, I could probably spend enough money to setup to profit from it. Otherwise, it is basically copper alloy contaminated with silver, no matter how thick the plating is. It's easy and cheap stuff to get and that's why you have it. Have you ever wondered why it's easy and cheap to get? It's because nobody wants it. Nobody wants it because it's a bitch to process at a profit.

 

[Dr. Poe]

Separate the solid from the plated silver. Here is a basic process for the solid silver:
Prepare a 50/50 nitric acid to distilled water solution (acid into water but not reversed).
Wash the solid silver with dish soap and rinse thoroughly.
Rinse again with distilled water.
Under a fume hood, add the diluted nitric acid a little at a time until all has been digested.
Add muriatic acid while stirring with a glass rod until a thick white precipitate is completely formed.
Let it settle then decant the copper nitrate into another container.
Wash the silver chloride with hot water and one or two drops of aqua regia while stirring.
Again let it settle and then decant the water.
Mix zinc powder with the silver chloride to make a gray mass.
Add muriatic acid to dissolve out the zinc as zinc chloride.
Wash the now black silver metallic powder with water and decant the water.
Dry the powder and put in a crucible.
Add soda ash to cap it off the top.
Melt it at 1900F.
Pour the molten metal into a mold pretreated with a release agent like corn oil or professional mold release spray.
This is just a basic way and assumes there is no mercury on the silverware.
Protect yourself and others from the nitric acid fumes. Beware of hydrogen from excess zinc and acid.
I tried to keep this simple. Do you guys think I made it too simple? Regards; Dr. Poe :roll:

 

[4metals]

The only problem with this method is you must be sure the zinc comes in contact with all of the silver chloride to reduce it, this requires good mixing or else you will leave behind un-reduced silver chloride and it will smoke like mad when melting it.

This method works fine just make sure it is mixed. You can't over mix it!

 

[element47]

The two schools of thought in silver refining seem to revolve around the desire / non desire to produce silver chloride. Personally, the method of cementing out the dissolved-in-nitric silver upon a chunk of copper, which avoids any use of HCl, and from there into a silver cell, would be my preference.