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16th century cupellation furnaces (per Agricola). Cupellation is a refining process in metallurgy in which ores or alloyed metals are treated under very high temperatures and subjected to controlled operations to separate noble metals, like gold and silver, from base metals, like lead, copper, zinc, arsenic, antimony, or bismuth, present in the ore.
Silver mining required large amounts of mercury to extract the metal from ore. In the Andes, the source was the Huancavelica mercury mine; Mexico was dependent on mercury from the Almadén mercury mine in Spain. Mercury had a high adverse environmental impact. [26] Silver was extremely valuable in China, and became a global commodity.
The Scandinavian silver alloy contains 83% pure silver and 17% copper or other metals. [10] German silver will be marked with a millesimal fineness of 800 or 835 (80% or 83.5% pure silver). Any items simply marked "German silver", "nickel silver" or "Alpaca" have no silver content at all, but are mere alloys of other base metals. [citation needed]
The silver is then recovered by volatilizing the zinc. [2] The Parkes process largely replaced the Pattinson process, except where the lead contained insufficient silver. In such a case, the Pattinson process provided a method to enrich it in silver to about 40 to 60 ounces per ton, at which concentration it could be treated using the Parkes ...
Thus, smelting, or refining, is necessary to reduce the compound containing the Ag + cation into metallic Ag and to remove other byproducts to get at pure silver. [1] The process, which uses mercury amalgamation to recover silver from ore, was first used at scale by Bartolomé de Medina in Pachuca, Mexico, in 1554. [2]
Fine silver, which is 99.9% pure silver, is relatively soft, so silver is usually alloyed with copper to increase its hardness and strength.Sterling silver is prone to tarnishing, [1] and elements other than copper can be used in alloys to reduce tarnishing, as well as casting porosity and firescale.
Another method uses Sterling silver instead of copper. One part pure gold is alloyed with three parts Sterling silver (inquarting). The resulting six karat (6K) gold can then be parted with dilute nitric acid (one part 68–70% nitric acid to one part distilled water).
Silver is found in the Earth's crust in the pure, free elemental form ("native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining. Silver is a naturally occurring element.