Copper can be found naturally as native metallic copper and was known to some of the oldest civilizations on record.

The history of copper use can be traced back to 9000 BCE in the Middle East; a copper pendant was discovered in northern Iraq that dates to 8700 BCE. Evidence indicates that gold and meteoric iron (but not smelted iron) were the only metals used by mankind before copper.

Discovery of Copper

Copper is present in the Earth’s crust in an average concentration of about 50 ppm. In nature, copper occurs in a large variety of minerals, including native copper (Cu), copper sulfides such as chalcopyrite (CuFeS2), bornite(Cu5FeS4), digenite (Cu9S5), covellite (CuS), and chalcocite (Cu2S), copper sulfosalts such as tetrahedite-tennantite (Cu6[Cu4(Fe,Zn)2]Sb4S13-(Cu,Fe)12As4S13), and enargite (Cu3AsS4), copper carbonates such as azurite(Cu3(CO3)2(OH)2) and malachite (Cu2(CO3)(OH)2), and as copper(I) or copper(II) oxides such as cuprite (Cu2O) and tenorite (CuO), respectively. The largest mass of elemental copper discovered weighed 420 tons and was found in 1857 on the Keweenaw Peninsula in Michigan, United States.

Most copper is mined or extracted as copper sulfides from large open pit mines in porphyry copper deposits that contain 0.4% to 1.0% copper. Sites include Chuquicamata, in Chile, Bingham Canyon Mine, in Utah, United States, and El Chino Mine, in New Mexico, United States. Copper can also be recovered through the in situ leach process.

Major Uses of Copper

Historically, copper was the first metal to be worked by people. The discovery that it could be hardened with a little tin to form the alloy bronze gave name to the Bronze Age. Traditionally it has been one of the metals used to make coins, along with silver and gold. However, it is the most common of the three and therefore the least valued. All United States coins are now Cu alloys.

The major uses of Cu are electrical wire (B60%), roofing and plumbing (B20%), and industrial machinery (B15%). Cu is used typically as the pure metal, but when greater hardness is necessary, it is combined with other metals in alloys such as brass and bronze (5% of total use). For more than 200 years, Cu paint has been used on boat hulls to curb the growth of plants and shellfish. A small portion of the Cu supply is used for nutritional supplements and fungicides in agriculture. Machining of Cu is possible, though alloys are preferred for good machinability in producing intricate parts.

Notwithstanding competition from other materials, Cu is still the preferred electrical conductor in almost all types of electrical wiring with the exception of overhead electric power transmission where Al is frequently preferred.

Cu wire is used in a variety of applications, for example, in power generation, power transmission, power distribution, telecommunications, electronics circuitry, and countless types of electrical equipment. This comprises structural power wiring, power distribution cable, appliance wire, communications cable, automotive wire and cable, and magnet wire. About 50% of all Cu mined is used for electrical wire and cable conductors. Numerous electrical devices depend on Cu wiring due to its characteristic beneficial properties, for example, its high electrical conductivity, tensile strength, ductility, creep (deformation) resistance, corrosion resistance, low thermal expansion, high thermal conductivity, ease of soldering, malleability, and ease of installation. Integrated circuits and printed circuit boards increasingly use Cu instead of Al due to its superior electrical conductivity.