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Melting is the act of turning a solid into a liquid by adding heat. Not to be confused with smelting, which is producing metals from ore via high temperature and chemical reduction. Melting of metals is usually done in a melting dish with a torch or in a crucible in a furnace. For amounts of up to a few hundred ounces, a melting dish is usually enough.
When melting pure silver it is important to keep oxygen away from it. Molten silver can dissolve up to 10 times it's volume of oxygen (0.3% of it's weight). When the silver solidifies all the oxygen is dispelled and can make the silver spit hot metal.
To minimize the effects of absorbed oxygen in pure silver during a melt there are a few techniques.
- Melting the silver in an inert atmosphere, for example nitrogen or argon gas.
- Using a reducing flame on top of the melt and the mold until the silver solidifies.
- Adding a tiny bit of lithium to the melt, a gram of lithium is enough to treat 1000 of ounces. The lithium creates a Li2O slag that ends up on the crucible walls.
- Ganoksin : Video of melting palladium with a TIG-welder.