Copper was known to some of the oldest civilizations on record, and has a history of use that is at least 10,000 years old. Most copper is obtained from sulphide ores. These are found admixed with large quantities of gangue and the initial content of copper may be very low. A concentrate containing 15 to 35% copper is produced by flotation.

For the purpose of eliminating some of the sulphur and certain impurities, the concentrate is usually roasted before smelting. Roasting is carried out in multiple-hearth furnaces, in which oxidizing reactions take place: sulphur is eliminated as the dioxide and metallic sulphides i.e. iron and some copper remain behind as oxides.

Copper is essential for computers to work. Copper is used in building the integrated circuits, chips, and the printed circuit boards of the computer alone. Copper is becoming more and more popular to use in the layers of the build-up of a chip. IBM announced a plan to use copper in its computer chip rather than aluminum. Doing so would make the computer to be cheaper and would allow it to make faster calculations. And one more thing statue of liberty is made of copper. It is green because the copper has combined with carbon dioxide and water in the air.

Copper, as native copper, is one of the few metals to naturally occur as an uncompounded mineral. No one knows exactly when copper was first discovered, but earliest estimates place this event around 9000 BC in the Middle East. A copper pendant was found in what is now northern Iraq that dates to 8700 BC. It is probable that gold and iron were the only metals used by humans before copper.

The mixture calcine contains the sulphides of iron and copper, together with gangue material and impurities. The next step consists in producing a molten artificial sulphide of copper and iron, known as matte, containing all the copper and desired amount of iron. For producing the matte smelting operation is generally carried out in a reverberatory furnace (Fig.2) fired with oil, natural gas or pulverized coal.

The charge is fed through the roof, and molten material collect in a pool at the bottom. Slag, which rises to the top, is tapped off. The matte collects at the bottom of the pool and is discharged through a taphole. The molten matte is fed to a converter (Fig.3) in which the iron and sulphur are removed by oxidation, which is effected by blowing air through the molten mass and is based on the fact that copper has a lower affinity for oxygen than has iron or sulphur.

The reactions in the converter occur in several stages. First the iron oxidizes and forms a slag with silica, which has been added to the charge; this slag is tapped off, the copper then being present as the sulphide. Further oxidation results in the formation of metallic copper with a small amount of copper oxide and other impurities. The converter in which the process is performed is a large revolving refractory-lined drum.

The copper obtained in the converter is subjected to further refining treatment, which consist in fire refining (in furnaces) followed by electrolytic refining. Fire refining is done in small reverberatory furnaces or in revolving furnaces similar to the copper converter. Air is blown through the molten material to oxidize all impurities; the oxides rise to the surface and are skimmed off. This is then followed by a reduction process which is performed by forcing the ends of green logs into the molten metal to form highly reducing gases.

The copper obtained as a result of this treatment is called tough pitch. For further refining, it is cast into anodes for electrolytic refining cells (Fig.4). The system most widely used is known as the multiple system, comprising separate anodes and cathodes; the latter consist of thin sheets of high-purity copper. When an electric current is passed through cells, copper is dissolved from the anodes and is deposited in a very pure form on the cathodes. When these have grown to a thickness of about ½ inch they are replaced by fresh starting sheets.

Ore treatment may, alternatively, be carried out by hydrometallurgical processes in which the ore is treated with a solvent that dissolves the copper and leaves the undesirable material unaffected. This principle is applied more particularly to the oxide ores of copper, or to sulphide ores after suitable roasting, sulphuric acid being used as the leaching solvent. Elaborate washing, filtration and purification of the leach solution are associated treatments.

Copper is essential in all plants and animals. Copper is carried mostly in the bloodstream on a plasma protein called ceruloplasmin. When copper is first absorbed in the gut it is transported to the liver bound to albumin. Copper is found in a variety of enzymes, including the copper centers of cytochrome c oxidase and the enzyme superoxide dismutase (containing copper and zinc). In addition to its enzymatic roles, copper is used for biological electron transport.