Copper is one of the oldest metals known to man, having been in use for thousands of years. In modern times, copper continues to be used in piping, electrical circuits, coins, and kitchen utensils. Last year 15,400 metric tons of copper content were produced.
Physical properties: Copper is a ductile, reddish metal that is an excellent conductor of heat and electricity. However, pure copper is a pinkish-peach color, and that color can be seen best when a bright light is shone on liquid copper. Without the light, liquid copper is a greenish color, a property similar to gold. Copper is an excellent conductor of both heat and electricity, second only to silver. It melts at 1085C, and boils at 2562C. Copper is moderately dense (8.96 gram/cm3) and quite soft (3 on a 10 point scale).
Chemical properties: Copper turns brown soon after it is placed in air, as it develops a thin layer of oxides. When copper is burned in oxygen, it gives off black oxides.
Many molluscs and arthropods, such as the horseshoe crab use the copper-containing pigment called hemocyanin, instead of the iron-containing haemoglobin. Haemocyanin makes their blood blue, instead of red like that of mammals.
History: Since some copper can be found in its pure form, it has been used for at least 10,000 years. No one knows exactly when copper was first used, but the remains of a copper pendant have been found in Iraq, and is thought to be from 8700 BC. Iron and gold are the only metals likely to have been used before copper. There are signs of copper smelting in Serbia in 5500 BC. In Asia, people were investing in copper over 6000 years ago. It is possible that copper smelting started in Southern Europe, near Greece. It is also thought that copper smelting was learnt by each civilization independently, by Southern Europe in 5500 BC. Ötzi the Iceman, a well preserved European male from 5300 years ago was found with an axe with a head made of 99.7% pure copper. Tests done on his hair showed high levels of arsenic, so he might have been working in smelting copper. A lot of copper was found in the Indus Valley Civilization of 3000 BC. This period was known as the Copper Age of human civilization. China learnt copper smelting in 2800 BC, and it reached the Andes by 2000 BC. Copper smelting began in Central America in 600 AD, and in West Africa in 900 AD.
The discovery of bronze (the alloy formed by tin and copper) came soon after the discovery of copper. We have found bronze artifacts made by the Sumerians in 3000 BC, and a few made by the Egyptians around the same time. In one of the pyramids, there is a 5000 year old plumbing system made of copper. Egyptians discovered that if you added a little tin to copper, it became easier to mould. Because of this reason, the Egyptians started to use bronze very soon after discovering copper. There were very important copper mines modern-day southern Israel and Jordan. By 2000 BC, Europe too was using bronze. It was used so much that a period of time from 2500 BC to 600 BC was named the Bronze Age of human civilization. A copper mine in North Wales at Great Orme, 70 metres deep, is probably 4000 years old. The Greeks then discovered brass, an alloy of copper and zinc, and while they did not use it much as copper or bronze, the Romans after them used brass a lot.
So much copper was found in Cyprus, the metal's name was changed from "chalkos" to "cyprium", then simplified to "cuprum", and finally changed to "copper" by the English. Copper, along with its alloys bronze and brass, has been used throughout the medieval times, and still continues to be in use today.
Production: Copper is mined from large open pit mines as copper sulphide. The impurities are removed through smelting, reduction and through other chemical reactions. In smelting, copper is melted down, and the impurities are taken off the top of the liquid copper. In reduction, oxygen is removed by sending natural gas through molten copper. In other production methods, impurities are reacted with other substances until pure copper is left. The top five producers of copper in the world are Chile, Peru, the United States, China and Australia. Pie Chart of Top 5 Copper Producing Countries...
Uses: Since copper is malleable and ductile, and a good conductor of heat and electricity, it has a variety of uses. Because copper is too soft for some uses, copper alloys like bronze and brass are used. In piping, copper is used since it is easy to mould into the shapes needed. Much copper goes into electronics, to make wires, transformers, and circuit boards. In building and architecture, copper is used to make buildings and ships water proof, and in household uses it is used to make anything from doorknobs to frying pans. Copper has been used to make coins throughout history, and is also used as a coating on zinc pennies to give them a shiny, bronze-like color. There are various other minor uses of copper such as ammunition (jackets for bullets) and glass-making.
Health: Copper is an essential part of plant and animal life. It moves around the body on a plasma protein called ceruloplasmin, and is then absorbed by the liver. Copper is also found in the centre of many enzymes in the body. The recommended daily consumption of copper is three milligrams, and the deficiency of copper in the diet can cause health problems. Since zinc and copper compete for absorption, a diet that has too much of one tends to have too little of the other. However, too much copper in food can cause poisoning: many Indian children got copper poisoning from drinking milk boiled in copper vessels.
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