Physical properties and uses of copper

Native copper is an element and a mineral. It is found in the oxidized zones of copper deposits; in hydrothermal veins; in the cavities of basalt that have been in contact with hydrothermal solutions; and as pore fillings and replacements in conglomerates that have been in contact with hydrothermal solutions. It is rarely found in large quantities, thus it is seldom the primary target of a mining operation. Most copper produced is extracted from sulfide deposits.

Physical properties

Native copper has a distinctive reddish/brown color. Its first oxidation state (+1) formscompounds with copper ions named “cuprous,” also referred to as “copper(I),” and these ionsare easily oxidized with elements in group 16 (e.g., oxygen and sulfur) and elements in group17 (the halogens).Copper’s second oxidation state (+2) forms cupric compounds, also referred to as copper(II),which are more stable than copper(I) compounds. For example, copper in both oxidationstates can combine with fluorine: for copper(I) or cuprous fluoride, Cu⁺ + F^- → CuF; and forcopper(II) or cupric fluoride, Cu²⁺ + 2F → CuF₂.Copper’s melting point is 1,083°C, its boiling point is 2,567°C, and its density is 8.94g/cm3.

Occurrence

Copper is the 26th most abundant element on Earth, but it is rare to find pure metallicdeposits. It is found in many different types of mineral ores, many of which are close to thesurface and easy to extract. It is found in two types of ores: (1) sulfide ores, such as covellite,chalcopyrite, bornite, chalcocite, and enargite; and (2) oxidized ores, such as tenorite, malachite, azurite, cuprite, chrysocolla, and brochanite.It is found in most countries of the world, but only a few high-grade deposits are costeffective to mine. Examples of some of its ores are cuprite (CuO2), tenorite (CuO), malachite[CuCO3- Cu(OH)2], chalcocite (Cu2S), covellite (CuS), bornite (Cu6FeS4), and chalcopyrite,also known as copper pyrite.Copper ores are found worldwide, in Russia, Chile, Canada, Zambia, and Zaire and, in theUnited States, in Arizona, Michigan, Montana, Nevada, New Mexico, Tennessee, and Utah.High-grade ores of 99% pure metal were found in the United States (and other countries), butmany of these native ore deposits have been mined over the past hundred years and are nowexhausted. Even so, many low-grade ores with concentrations of 10% to 80% pure copper stillexist and await a technology that will make them more profitable for exploitation.

Uses of Copper

Native copper was probably one of the early metals worked by ancient people. Nuggets of the metal could be found in streams in a few areas, and its properties allowed it to be easily worked without a required processing step. Today most copper is produced from sulfide ores.

Copper is an excellent conductor of electricity. Most copper mined today is used to conduct electricity - mostly as wiring. It is also an excellent conductor of heat and is used in cooking utensils, heat sinks, and heat exchangers. Large amounts are also used to make alloys such as brass (copper and zinc) and bronze (copper, tin, and zinc). Copper is also alloyed with precious metals such as gold and silver.