Copper

Neolithic humans first used native copper about 10,000 years ago

Native Copper

Copper is a reddish chemical element, an extremely ductile metal and is second only to silver as a conductor of electricity and heat. It has a pleasing color and luster, it takes a high polish, and it forms alloys readily with almost all metals.

Copper found in the free metallic state in nature is called "native copper." It is found throughout the world as a primary mineral in basaltic lavas. The greatest known deposit of copper is in porphyries formed by volcanic activity in Chile's Andean mountains. Copper was named for the island of Cyprus, where the Romans obtained their supply.

History

Neolithic humans first used native copper about 10,000 years ago as a substitute for stone. The Egyptians and the Sumerians invented metallurgy, first reducing ores with fire and charcoal about 4000 BC. Copper was intentionally alloyed with tin as bronze about 3500 BC, and this harder metal was so universal in early history that one period is known as the Bronze Age.

Copper is easily worked and is remarkably ductile. It can be cold-rolled down to one one-thousandth inch in thickness, and, by cold drawing, its length can be increased as much as 5,000 times. Hence it is an ideal metal for making wire.

Production

Copper-bearing ores fall into two main classes: oxidized ores and sulfide ores. The oxidized ores, such as cuprite and tenorite, can be reduced directly to metallic copper by heating with carbon in a furnace. The sulfide ores, such as chalcopyrite and chalcocite, require a more complex treatment in which low-grade ores must be enriched before smelting begins. Sulfide ores are more important commercially. Half of the world's copper deposits are in the form of chalcopyrite ore.

Ores are removed either by open-pit or by underground mining. Ores containing as little as .15% copper can be mined profitably in open-pit mining, but underground mining is profitable only if an ore contains 6% to 7% copper.

For many years, Chile has been the world's largest producer of copper, followed by Peru, China, the Democratic Republic of Congo and the United States. After Arizona, the leading copper-producing states in the U.S. are Utah, New Mexico, Nevada, Montana and Michigan.

Distribution

Most of the copper produced in the world is used in electrical products. Another third is used in metal products such as pipe, tubing, plumbing fixtures, hardware, and machine tool products. Most is combined with other metals to form more than 1,000 different alloys. Important alloys in which copper is the chief constituent are brasses (copper and zinc), bronzes (copper and tin), and nickel silvers (copper, zinc, and nickel).

Copper is used in nearly all coinage and remained the second most utilized metal (after iron) until the 1960s when cheaper and more plentiful aluminum surpassed it in world production. Copper is also a trace element essential to the healthy life of many plants and animals, in which it usually occurs as part of oxidizing enzymes.

Copper Facts

• Copper is mankind's oldest metal, dating back more than 10,000 years. A copper pendant discovered in what is now northern Iraq dates back to about 8700 BC.
• Archeologists have recovered a portion of a water plumbing system from the Pyramid of Cheops in Egypt. The copper tubing used was found in serviceable condition after more than 5,000 years.
• When Columbus sailed to the Americas, his ships, Nina, Pinta and Santa Maria, had copper skins below the water line. The copper sheathing extended hull life and protected against barnacles and other kinds of biofouling.
• Paul Revere produced the bronze cannon, spikes and pumps for the famous ship, Old Ironsides. Revere was one of the earliest American coppersmiths.
• Each year in the U.S., nearly as much copper is recovered from recycled material as is derived from newly mined ore.
  • An average single family home uses 439 pounds of copper:
  • 195 lbs. building wire
  • 151 lbs. plumbing
  • 24 lbs. brass goods
  • 46 lbs. Built-in appliances
  • 12 lbs. builder hardware
  • 10 lbs. misc wire and tube
• There are more than 50 pounds of copper in an American-built automobile.
• There are about 9,000 pounds of copper in a Boeing 747-200 jet plane.
• The Statue of Liberty contains 179,000 pounds of copper

Physical Properties of Copper

• Atomic number: 29
• Atomic weight: 63.546
• Melting point: 1,083 degrees C
• Boiling point: 2,567 degrees C
• Tensile strength: approx. 19,000 psi
  
  

COPPER CHARACTERISTICS

Chemistry	Crystal System	Hardness
Cu	Face-centered cubic crystal	3 (Mohs' scale)
Cleavage	Fracture	Specific Gravity
None	None	19.3
Color, Transparency & Luster	VARIETIES
- Color reddish - Luster bright, metallic - Streak is uncolored	Native copper: Cu - Red Chalcopyrite: CuFeS(2) - Brass yellow Bornite: FeS.2CU(2)S.CuS - Red brown Enargite: 3Cu(2)S.As(2)S(5) - Gray black Tetrahedrite: 4Cu(2)S.Sb(2)S(3) - Gray black Cuprite: Cu(2)O - Red Malachite: CuCO(3).Cu(OH)2 -Green Azurite: 2CuCO(3).Cu(OH)2 - Blue

 

 

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