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Gold, Silver, Copper, and Ores Help

By — McGraw-Hill Professional
Updated on Sep 4, 2011

Gold, Silver, And Copper

Since the first shiny speck caught the eye of early humans, gold, silver, and copper have been used for coins, jewelry, and household serving ware. Resistant to rust and corrosion, they were an excellent choice for coins, while being doubly useful in showing the local king’s face to strangers passing through the country.

Gold, a shiny yellow metal, is a good conductor of heat and electricity. It is the most malleable and ductile metal. The early alchemists based their reputations and lives on providing more of this metal to their patrons.

In the western United States during the Gold Rush days of the 1800s, gold fever affected thousands of people seeking their fortunes and a better life. Miners spent from morning until night hunched over icy mountain streams panning stream gravel and watching for the bright glint of a single gold nugget. Even today, people get excited over flecks of gold (iron sulfide, FeS 2 ) found in rock.

Silver, a brilliant white, lustrous metal, is the best conductor of heat and electricity of all the metals. It was also prized by early peoples for its beauty and uses. Silver, though, is less resistant to corrosion and will tarnish, turning black when it oxidizes in the air. It was thought that the state of Nevada was admitted to the Union in 1864 during the Civil War to provide funds to the Union and easier access to its resources of silver. Silver is used in coins, jewelry, electrical contacts, mirrors, circuitry, photography, and batteries.

Copper has an orange-brown color that is used in pipes, electrical wires, coins, paints, fungicides, and in alloys combined with other metals. In some countries, local artisans use copper for platters, bowls, tools, and jewelry. Pennies though once 100% copper are now (since 1981) only treated on the outside with copper plating to give the United States one cent coin its reddish-brown (copper) color. Many years ago, the badges of policemen were made from copper and so the slang expression “copper” or “cop” was used.

Ores

Unlike gold and silver, which are pure elements, many metals are not found in nature as a single element. Most metals are combined with other elements within ores that must be processed to extract their different parts. Table 9-9 gives examples of different ores and the metals they contain.

Table 9-9 Mineral-rich ores contain a combination of two or more elements.

Element

Ore

Found in

Aluminum

Bauxite

France, Jamaica

Bismuth

Bismite

  • USA

Chromium

Chromite

South Africa, Russia

Cobalt

Cobaltite

Germany, Egypt

Copper

Chalcopyrite

Cyprus, USA, Canada

Iron

Hematit

  • USA, Australia

Lead

Galena

  • USA, Brazil, Canada

Mercury

Cinnabar

Algeria, Spain

Nickel

Pentlandite

Canada

Tin

Cassiterite

Bolivia

Tungsten

Wolframite, Scheelite

Spain, China

Zinc

Sphalerite

Australia, Canada, USA

 

Pure metals are separated from ores primarily by heat. This is done in a high-temperature blast furnace. By adding reactants, like limestone and coke (a carbon residue) to break hydrogen bonding and release the bonded metals, individual metals can be collected.

Lead, though sometimes found as a pure metal in nature, is usually found as the ore galena or lead sulfide. Lead ore is crushed, heated in a blast furnace, and then extracted. Most lead produced in the United States is used for batteries and batteries’ electrodes. Lead solder is used in making connections on computer circuit boards.

Mercury is most often found in nature as the ore, cinnabar . Cinnabar, also called vermillion , is a bright red mineral that was crushed to a powder and used by Renaissance painters to make a deep red paint pigment.

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