Silver has been known since ancient times, but its usage is more recent than that of gold. The cupellation process is believed to have been developed in the 6th or 7th century BC while the metal itself was used as a currency as early as 5000 BC. Use of the word silver as a synonym for money dates back to the Middle Ages. It was during this period that silver mines began to be exploited throughout Europe. The discovery of silver deposits in the ‘New World’ after 1492 had a huge impact on the role of silver throughout the world and mining of silver thereafter dramatically eclipsed anything that had come before.
Between 1500 and 1800, Bolivia, Peru and Mexico accounted for over 85 percent of world production and trade. The name of the metal is derived from the Greek αργυρος, which means shiny. The name of the pound sterling (£) reflects the fact it originally represented the value of one pound weight of sterling silver.
- A shiny white metal, more ductile and malleable than copper, but slightly less so than gold.
- Its electrical and thermal conductivities are higher than those of any other metal; its electrical conductivity is 8% higher than that of copper.
- When solidified in air, the metal presents a blistered surface because of the release of dissolved oxygen.
- The most significant end-use for silver in volume terms is in industrial applications. Unalloyed and alloyed silver contacts are used in electrical applications, and unalloyed silver relays and contacts are used in electronic applications.
- As an alloy it positively influences the properties of brazing alloys that are used for joining miscellaneous metals and ceramics, for example in refrigerators, saw blades, radiators or electrical motors.
- Jewellery and silverware make up about 20% of total world demand.
- Photography remains an application, although this has been largely superseded by digital photography. Silver halides are sensitive to light, which causes them to decompose and form minute nuclei of silver metal, which are grown using an appropriate reductant. The undecomposed halogenide is then removed by means of a fixing agent.
- The metal is used in mirrors (silvering) and in dentistry.
- Silver is also used as a catalyst in the production of ethylene oxide and formaldehyde.
- The oxide Ag2O is used in the manufacture of button batteries.
- In silver plating, use is made of silver cyanide solutions from which silver is electrodeposited. Silver salts have found some applications on account of their bactericidal action.
- Silver is also finding a use for its anti-bacterial properties and is incorporated in clothing such as socks to reduce the smell !
Silver is recovered from the residues of copper, nickel and lead refining processes as silver is mainly found in ore bodies together with these metals. Silver is also recovered from industrial scraps and end-of-life applications like electronic and electrical scrap.