Home/Sitemap  ·    Search   ·   you are here: Forum =>letter 30693 Refining silver from smithing ++++ I do lost wax casting and smithing. I refine gold with nitric acid at home, by mixing scrapgold of different karat with copper and then disolving it in slightly hot nitric acid. That works very well for me. I have never come over a description as how to refine silver scrap, of which I get different amounts now and again. Mixed with solder, (chain links) or too much copper (coin silver) and so I ask if you can tell me how to refine scrap silver in my own workshop to get it (close to) pure again. Alexander Baldal gold and silver smith - Sint Maarten, Dutch West Indies, Netherlands Antilles ++++ I used to dissolve out my silver scraps in Nitric acid (at around 30% strength) This gave me a solution of Silver Nitrate (which is poison and will also burn or mark you or your sink or clothes - it will also burn out a wart or corn with several applications!! It can also be used to purify water (but I do not know what is a safe way to do this.) I assumed that any lead or copper or zinc did not react with nitric and just fell to the bottom as "dirt". I poured this solution into a fresh glass (leaving the "dirt" behind. Then I mixed in a hot fairly strong salt solution and the silver nitrate precipitated out a white substance which you could filter off with a paper towel in a funnel. This white precipitate can be heated with your torch in a crucible and I got what I believed to be pure silver. I used to use it for casting as I suspected it was not as pure as I would have wished. I gave the remaining liquid a second dose of hot saline in case it still contained any silver. My father in law, a chemist (in Aruba!) gave me this procedure. Don O'Keefe - Guatemala ++++++ I have found many different sites telling me how to refine silver with nitric acid. I was wondering if there is any other method I could use at home to refine it? Sean Peter Cake hobbyist - Kutztown, PA, USA +++++++ Not to mess with expensive nitric acid from the pahrmacy I found the cheaper way to refine silver. I put 50 gram of Sodium Nitrate from a garden supply shop, (is a common fertilizer) in half liter Sulphuric acid from a car supply shop (is common lead battery acid) and in it unclean silver, in as small parts as possible, milled flat and cut, and/or filings, in a glass coffee pot that can take a gas flame and boil it for one or two hours, (no need for a lid as the water in the weak acid evaporates and makes it stronger) or until all is dissolved, pour the liquid through a common coffee filter. What undisolved metal stays in the filter goes in the next batch. Then I add very fine common kitchen salt, dissolved in a little hot water or just like that; dry. The white yoghurt like substance (precipite) comes down in the liquid, untill more salt does stay salt. Then pour the liquid through a new coffee filter and rinse with water until clean, to check add a little amoniac (Janitor strength from the hardware store). If the rinse water turns blue, rinse more. Good to rinse last with distilled water (wich I catch from my airconditioner). Put the filter with the white stuff in a crucuble in a burnout oven if you have, heat to 800 celcius, then remove from oven and put the torch, (Propane Oxygene will do) to get 100% pure silver. If you have no oven, let the filter dry , dip in alcohol and heat with torch. Same result. The same procedure for low karat gold, what stays in the filter after 2 hours cooking put in Muriatic Acid [link is to product info at Amazon] with Sodium Nitrate, the gold will dissolve in room temperature, slowly, over night. Filter the liquid, what stays in the filter, rinse well and pour off what is light, any bits and pieces are good for a next time. Disolve some Urea ( also from the garden supply shop) in hot water and pour it slowly in the acid. It will foam and get hot, put your container in a big glass bowl in case it runs over. After the urea solution has gone in sprinkle Metabisulfite (is a salt butchers use to keep meat from turning brown, also used in wine making, water purifying, a common house hold item in a pharmacy) and see it foam and smell it stink, do work upwind. When brown-red particles go down, that is the pure gold. Instead of Metabisulfite you can use common copper, old water tube or electric wire. As long as the copper dissolves the gold is pushed out of the acid. When the copper does not turn black any more the gold is out of the acid. To test for gold in the acid, make test water. That is pure tin, (lead free water tube solder from the plumber department hardware store) dissolved in a little muriatic acid. Put a drop on a paper towel, then add a drop of the liquid to test for gold. If it gets black gold is in, if it does not turn black all the gold is precipitated. Good luck and have baking soda [link is to product info at Amazon] at hand to neutralise any acid spill. Put a bowl with baking soda in water to dip hands and rinse acid tools. Filter, wash and rinse like the white stuff, the pure gold does not turn black after cooling in air. Alexander Baldal Atelier Amador - Sint Maarten Netherlands Antilles Ed. note: Thanks you, Alexander. Readers please remember that the internet is a one-room schoolhouse and that some of the instructions you read on the internet may be totally inappropriate for a home environment or for application except by trained professionals. February 3, 2008 Just a warning, anyone who is using these methods: dissolving the silver in nitric acid works well, be sure not to breath in the toxic fumes. Also, the white powder formed after adding salt to the silver solution is silver chloride. Heating this powder with a torch will give you pure silver, but it also produces pure chlorine gas, so be very careful if you are using this procedure. A safer way to recover the silver is to mix the silver chloride with sodium carbonate (can be bought at pool supply stores), heat to around 1200 degrees C, then pour out the mixture. Products are table salt and pure silver, which will separate in liquid phase due to extreme density differences. If you know anything about chemistry, you can work out the reactions and mass ratios. Cheers, happy refining. Dave Bahn - Penn State, PA, USA July 22, 2008 I am purchasing a high temperature smelting furnace for melting down items that are "pure" as possible and other masterials that have mixtures of gold and silver, silver and copper or a mixture of all three. How am I to seperate these precious metals from one another and how do I make the final outcome the finest grade possible? Duke McNichol metal detector enthusist - Clayton, NC U.S.A. September 10, 2008 assuming your scrap is either .925 or sterling there isn't much need to really refine it and it's impossible to refine to purity without a electrolysis. The purity of anything marked 925 or Sterling is already 92.5% pure silver. One method of reducing some of the impurities would be to dissolve the silver in a 30-35% nitric acid solution. This solution will give off poisonous and acrid fumes so use a hood, vent or do this outdoors. for an ounce of silver scrap (again assuming it's .925) you might want to use about 1.5oz of diluted nitric. when no more silver is present, filter the solution and then you can recover the silver by adding muriatic (HCl) or regular non iodized table salt. Both will precipitate the silver as silver chloride which will have to be reduced to metallic silver by either a calcining process or reducing with zinc. An easier method of recovering silver from silver nitrate is to simply add a piece of clean copper. This will cement your silver as cement silver which will run about 94% pure. Again, to refine the silver to 999 purity, it will require electrolysis Greg Alford - Kansas City, Ks, USA September 28, 2008 Refining Silver From a Mine? I've recently come home from a "Silver Hunting" trip from some past producers. I've found some nice samples of wire and plate silver which I want to keep. I've also found some ore that contains a high content of Cobalt and Arsenic not much visible Silver so I cannot visually remove the Silver. How could I remove the Silver (in small batches 1-2 lbs total ore weight) safely and cost effectively.I want to have a local Jeweller make some silver Crosses for my Wife and Daughters for Christmas. Andy Kerr rock hound and amateur prospector - Queensville, Ontario, Canada August 8, 2009 the simplest way to extract gold from mixed ore after powdered to over 100 microns? right on the mining site, with less complicated resources possible, fast easy and efficient, please any one know how? thank you I always pray for the peace of Jerusalem so you may prosper (that is what the Bible states) I follow! Jose Brienza - Newton Falls, Ohio July 8, 2010 An easy (all disclaimers included) way to separate fine gold from jewelry is an old method called "Parting" I put this site up a few years ago. Some of it is incorrect, like the names of things. But parting is an old method and it works. I wouldn't recommend it to the casual putterer, but if you're not scared of dying, it's fun! custommadesilver.com/Tutorials/Refine.htm Robert Hale the department of redundancy dept. - Powell, Tennessee, USA Dear Reader: please choose what you want to do-- I want to Answer or follow-up on this subject (in non-commercial fashion).   I want to post a new question or inquiry on a different subject.   This is a monitored forum. If you spot broken links or obsolete info, please advise!