Silver (AKA poor mans Gold), amongst the 8 precious metals (Gold, Silver, Platinum, Palladium, Rhodium, Ruthenium, Iridium,
Osmium) is probably the most used metal in the different industries, e.g. - electronics/electrical/jewelry/photography/printing etc'… and
with good reasons.
Despite Silver's low price, it holds superior physical properties over most other non precious metals. In most applications Silver is used as part of an alloy rather then in pure form (mainly due to its high malleability), it is then when its physical properties are shown in all of their glory, in terms of electrical and thermal conductivity, oxidation resistance, jewelry and jewelry coloration.
Examples: Electrical contact point, high temp' solder, electrodes, green gold and more…
Silver and its compounds have countless other applications in all sorts of fields, Such as: Jewelry, silver plating applications, laboratory usage as catalysts, film and printing (fixer solutions, litho printing), Dental works, Gold and Platinum group metals refining, water purification, cloud seeding, cosmetics… you name it… the sheet is too short to count them all.
As you probably realized by now, Silver is all around us in our daily life and demand is ever growing. Taking this information with some reports on dwindling worldwide Silver natural resources (assumed to be even less availability then gold), one can truly appreciate holding on to Silver Bullion & Silver bearing scrap.
In some cases silver scrap is not worth recovering (due to current low price of Silver) and in others it does. It all depends on Silver availability within the scrap and how straight forward the recovery process is.
In our recovery section, we will present in the following articles some of the main sources of Scrap Silver, propose and demonstrate a recovery method for each source.
Here are a few examples for scrap silver:
- Spent Fixer solutions, Lithographic ink and x-ray films.
- Sterling Silver jewelry and flatware.
- Different Silver alloys.
- The use of Scrap Silver in Gold refining.
- Contact points
Same as any other noble metals, silver, once recovered needs to go thought a refining process, we will also discuss the different refining routs that fits each recovery method and its product. The goal of refining is of course achieving 999.5 fine silver, even though some methods are able to produce 999.9 Fine silver.
Examples for Silver refining methods:
- Metal displacement (using more reactive metals, also called cementing)
- Chemical reduction from Silver bearing solutions.
- Electrochemical deposition of silver bearing solution (i.e. – silver cell)
Dou to Silver's rather unique chemical behavior, most refiners (including the writer) does have some kind of love / hate relationship with Silver and its halides compounds (e.g. – bromide, iodide and chloride).
Why Hate? Silver halides are very insoluble and when formed, they tend to trap with them some dissolved values from main liquor, they are quite inconvenient to handle and conversion methods to elemental silver are usually long and tedious.
Why Love? Scrap silver comes cheap. Silver is sometimes a by product from other precious metals recovery/refining efforts and in most cases is a freebie.