History of Copper

Copper gets its chemical symbol Cu from its Latin name, cuprum. It got that name from the island of Cyprus, the source of much of the ancient Mediterranean world's supply of copper.

Native copper was mined and used in the Tigris-Euphrates valley (modern Iraq) as long as 7,000 years ago. Copper ores have been mined for at least 5000 years because it is fairly easy to get the copper out of them. For example, if a copper oxide ore (CuO) is heated in a wood fire, the carbon in charcoal can reduce the oxide to metal.

Copper is created in volcanic areas high in concentrations of hot sulfuric solutions. While copper is found worldwide, 90% of reserves are located in four areas: the Great Basin of the western United States, Zambia, central Canada, and the Andes regions of Peru and Chile. Antarctica too has copper ore deposits in many locations, but a moratorium on mining was established in 1991 to last for 50 years to preserve the vast land. To obtain the rare, pure copper requires smelting, leaching, or electrolysis. The most familiar forms of copper are pure copper, brasses (copper-zinc alloys) and bronze (copper-tin alloys). Found in nature mostly in impure mineral form (e.g. azurite, malachite, chalcopyrite, copper can also be produced by a biochemical process using the bacterium Thiobacillus ferrooxidans.

No one knows exactly when copper was first discovered, but earliest estimates place this event around 9000 B.C. in the Middle East. Present-day Israel, Egypt and Jordan were some of the earliest locations of copper smelting sites, dating back to about 4500 B.C. Located in southern Jordan, 30 miles south of the Dead Sea, the 70-room, 5000-year old Kirbat Hamra Ifdan foundry housed such copper artifacts as hammers and axes. Investment casting was realized in 4500-4000 B.C. in SE Asia (4000 B.C. in Thailand) and 3000 B.C. in Turkey. In India, artisans created copper alloy products such as icons and lamps. An Iron Age smelting site, Agia Varvara-Almyras, in Cyprus, had its complete operations recorded in written documents, which has contributed to much of our knowledge of ancient techniques. Metallurgical processes with copper alloys, most notably brass and bronze, were performed soon after an area's discovery of pure copper. The Egyptians had found that adding tin produce bronze makes casting easier, and they realized that an alloyed object is harder than copper alone. Tempering of copper was most likely discovered by accident, as was its malleability. Arsenic bronze objects were created in the Black Sea/North Caucasus area using the lost wax process.

One of the more amazing historical uses for copper, illustrating its staying power, was the copper tubing in ancient Egypt. It appeared to be constructed like today's plumbing fixtures. Found in the tombs and temples of rulers, much of this tubing remains in an excellent, even functional, state more than 5000 years after its first use. This is because the very malleable copper is not as susceptible to corrosion as other metals, which is why it is still used today for pipes. Unlike plastic, copper does not give off fumes, melt, or burn. In addition, copper has antibacterial properties that help to ward off microorganisms like those that cause Legionnaire's disease.

In the early 1800s, it was discovered that copper wire could be used as an insulator, but it wasn't until 1990 that copper, in oxide form, was discovered for use as a superconducting material. The German scientist Osann invented powder metallurgy of copper in 1830 while determining the metal's atomic weight. It was also discovered that the amount and type of alloying element (e.g. tin) would affect the tones of bells, allowing for a variety of rich sounds, leading to bell casting, another common use for copper and its alloys.

As we have seen, copper has been a major factor in nearly all aspects of history, technology, medicine, and culture. It remains crucial in a variety of technologies we are all familiar with today, such as the wire used to access the World Wide Web and chips in Pentium processors. Its importance will most likely continue with the rapid growth of the computer industry, relying on copper chips and copper-based solar power collectors, and with the massive quantities of copper used in the Space Shuttle (approximately 10,000 pounds!). Copper can also be recycled almost indefinitely without losing its form. In myriad shapes and for innumerable uses, it will be with us for a long time.