The mining of copper started in Cyprus in the Roman Era. From there emerged the original name of the metal which was Cyprium that meant ‘metal of Cyprus’. Later this name was shortened and the metal was renamed ‘Cuprum’. This also gives Copper its symbol ‘Cu’.
It is estimated that the discovery of copper took place around 9000 B.C. in the Middle East. It is one of the first metals discovered by man and ever since it has played an important part in the growth and development of mankind. Archaeological discoveries have shown that copper has been utilized by several civilizations for making tools, handicrafts, utensils, weapons and other household articles.
Copper is one of the most durable metals available. The condition of the remnants of the copper articles from archaeological discoveries demonstrates the metal’s durability and its resistance to corrosion. Copper has been ascertained to be the finest metal for supplying water. Copper pipes have been in use since many years and continue to evolve. The modern form of copper piping is strong yet light and highly resistant to corrosion. Copper piping serves all types of residential, commercial and industrial buildings.
Copper is ductile metal that is a very good conductor of heat and electricity and hence is used in many electrical applications. Pure copper is malleable and can be stretched easily. The exposed surface of the metal is in reddish-orange colour.
Chile in South America is the largest producer of Copper in the World. Copper has a wide range of application in Electrical, Transport, Aerospace, Heat exchangers, telecommunications, utensils and glass industry. It is an exceptional conductor of heat and electricity and hence finds wide usage in the power generation, transmission, and electrical applications.
Today, around 400 copper and copper-alloys are used in various applications. They are classified under categories such as copper, high copper alloy, bronze, copper-nickel, copper-nickel-zinc, brass, leaded copper and special alloys. These alloys are created to best suit the design applications. They are some of the basic metals that are used in domestic and industrial sectors.
Name of the Metal: Copper, named after Cyprus
Discovery: Middle East in 9000 B.C. era
Element Category: Transition Metal
Group, Period, Block: 11, 4, d
Electron Configuration: [Ar] 3d10 4s1
Standard Atomic Weight: 63.546(3)
Density (near r.t.):
Liquid density atm.p.:
Melting point: 1357.77 K, 1084.62 °C, 1984.32 °F
Boiling Point: 2835 K, 2562 °C, 4643 °F
Heat of Fusion:
Heat of vaporization:
Molar heat capacity:
Oxidation states: +1, +2, +3, +4?(mildly basic oxide)
Electronegativity: 1.90 (Pauling scale)
Atomic Radius: 128 pm
Covalent Radius: 132±4 pm
Van der Waals radius: 140 pm
COPPER – A METAL USED THROUGH THE AGES
The humans from very early civilizations have used copper. That shows that it is one of the first metals extracted by the human civilizations. Since then, it has made many important contributions to the improvement and sustenance of our society. The initial use of copper was limited to making coins and ornaments. It is estimated that copper was first used in making these articles about 8000 B.C. ago. As the civilizations developed, more uses of the metals were discovered. About 5500 B.C. ago, man started using copper to make tools and weapons. Later it was discovered that copper when alloyed with tin produced bronze. This discovery marks the beginning of Bronze Age at 3000 B.C.
Copper is a malleable metal. It can be stretched and moulded very easily. It is resistant to corrosion and is a good conductor of heat and electricity. For these reasons, copper has been an important metal since ages. Even today, it continues to be one of the best metals for a wide range of domestic, technological and industrial applications.
HOW DO WE USE COPPER TODAY?
Today, copper is used in a wide variety of industrial and domestic application. Construction, electronic product manufacturing, industrial machinery production, transport vehicle production and power generation and transmission are some of the sectors in which copper plays an integral role.
It is estimated that about 65 per cent of the copper produced finds utility in electrical applications. Copper is an exceptional conductor of heat and electricity and hence is greatly used in power generation and transmission and electrical applications. For power generation and transmission, copper is used in manufacturing generators, motors, transformers, cables and busbars. They ensure safety and efficiency of these equipments. In Electrical applications, copper is used to provide circuitry and wiring for electrical equipments.
Copper has also found an increased use in semiconductor manufacturing industry. It is used in making silicon chips and rotors. Copper helps in making these equipments more efficient by making them operate faster with lesser power consumption.
About 25 per cent of the World’s copper is used in construction activities. Copper forms an important part in plumbing, cladding and roofing. Copper is durable and light. These properties help the builders to erect structures that require minimum maintenance and last very long.
Transport is another leading industry that finds substantial copper application. Around 7 per cent of the World’s refined copper is used in trains, cars, trucks and trams. Copper wires are used in these systems to ensure current flow from the battery to equipments such as lights, GPS, chargers and other systems in the vehicle. Copper is the vital component in radiators, wiring, motors, bearings of transport vehicles and brakes. On an average, a car 1.5 km of copper wiring and 20 kg to 45 kg of copper is used in its manufacturing.
The very early usage of copper was limited to making coins and ornaments. Even now, many countries use copper to make coins. However, over the years new uses of the metal have been identified. Using copper in frequently touched surface is a relatively newfound use of the metal. Copper has antimicrobial properties that reduce the likelihood of transfer of germs and allergies. This has made it apt for usage in frequently touched surface such as doorknobs.
Industries in heating and cooling systems, appliances and telecommunication cables have high usage of copper materials.
USEFUL PROPERTIES OF COPPER
Copper has exceptional alloying properties. Copper when alloyed with zinc produces brass and when alloyed with tin produces bronze. It is also alloyed with nickel. Depending upon the composition of these alloys, they have desired characteristics that are then used in specialized applications. For instance, a defined composition of copper-nickel alloy is used in manufacturing of ship’s hull. This is to ensure that the hull does not corrode in sea water and reduction in adhesion to marine life. Use of copper in manufacturing hull also increases its fuel efficiency. Brass is used in musical instruments, as it is easy to stretch and mould and has good acoustic properties.
Copper is created in the Stars and forms a part of other celestial bodies. It is found in Earth’s crust at a concentration level of 50 ppm. It is either found as native copper or in mineral oxides. Some of these oxides are copper sulphides chalcocite and chalcopyrite, copper oxide mineral cuprite, and copper carbonates azurite and malachite. Largest mass of elemental copper was found in Keweenaw peninsula in Michigan in United States. It weighed around 420 tonnes.
TYPES OF COPPER DEPOSITS
Copper is present in many forms depending under the conditions that it is deposited. The metal finds occurrence in many different minerals. The most abundant and cost-effective copper mineral is Chalcopyrite.
Broad classification of copper can be done on the basis of how the deposits are formed. About two-third of world’s copper comes from Porphyry copper deposits. This is the most important type of copper deposit. North and South America contain large Porphyry copper deposits in its mountain regions.
Copper containing sedimentary rocks are another important type of copper deposit. These form one-fourth of the World’s copper resources. They are found in Central Africa and Zechstein Basin of Eastern Europe.
Copper deposits occurring individually contain millions of tonnes of copper. Open pit mining methods are used to commonly develop these deposits. Once the ore is discovered, mining operations last many years to extract the deposits in the area. Over the years, the mining regulations have been made stringent to minimize the impact of mining operations on the environment.
COPPER SUPPLY, DEMAND AND RECYCLING
The supply and consumption of copper have increased significantly in the past 30 years. These years have seen developing countries becoming a part of the global market, thereby increasing the demand for mineral commodities such as copper. Andean Region of South America has emerged as the leading producer of copper in the past 20 years. About 45 per cent of the World’s copper was produced in this region in year 2007.
The disruption of Copper supply is likely to have a severe impact on many industries such as construction and power transmission. However, the supply is expected to remain stable as the metal production is dispersed across the World and not limited to any particular region.
Of all metals, copper is of the widely recycled. It is estimated that around one-third of copper consumed is recycled. Copper and its alloys can be recycled safely for direct use or can be further processed to make refined copper. This does not affect any physical or chemical property of the metal and it remains as efficient as it is in the first use.
TYPES OF COPPER ALLOYS
Many copper alloys exist today having specialized utility. Copper when alloyed with zinc produces brass and when alloyed with tin produces bronze. It is also alloyed with nickel. An alloy of copper and nickel is call cupronickel. Depending upon the composition of these alloys, they have desired characteristics that are then used in specialized applications.
Copper is also an important constituent of carat gold and silver alloys. They are used to modify solidity, melting point and color of these metals.
The alloy of copper and nickel – cupronickel – is used in making coins by some countries. The 90 per cent copper and 10 per cent nickel alloy has great resistance to corrosion and hence are used in manufacturing of sea hulls and other equipments that are constantly exposed to the sea water.
Alloys of copper and aluminium also exist. Alloy consisting copper and about 7 per cent aluminium has a golden colour that is used in creating decorative pieces.
Most of these alloys have exceptional resistance to corrosion and are very good conductors of heat and electricity. The high copper alloys are mostly used in advanced mechanical operations. Various grades of copper exist. They are classified on basis of the impurities they contain. Oxygen free copper is mostly utilized in application that requires ductile metal having good conductivity.
Brass is an alloy of copper and zinc. Alloys with 32 per cent to 39 per cent zinc are display very good hot working characteristics. However, cold workability of these alloys are only limited. The amount of zinc increases the strength and ductility of the metal at room temperature. Alloys that have more than 39 per cent of zinc content have higher strength and ductility than alloys that have lower content of the metal. Depending upon the amount of zinc present in the alloy, the colour of brass ranges from red to a golden-yellow. Some common categorizations of brass depending upon the amount of zinc present in them are Commercial bronze, Red Brass, Jewellery Bronze, Cartridge Brass and Gilding Metal.
Brass is used in making jewellery, fire extinguishers, radiator cores, ammunition, lamp fixtures, gold plate bases and flexible hose. They are very easy to use for fabrication and have exceptional casting ability. They are also used in decorative hardware, low pressure valves, gears and bearings, architectural rims and plumbing fixtures. The alloy also has a very good corrosion resistance. Elements such as lead, phosphorous, manganese, chromium, beryllium and tellurium are also added to brass to further enhance its properties such as strength and durability. Most of these elements have negligible effect on its corrosion resistance properties.
Tin Brass are copper and zinc alloys. The zinc content in this alloy can range from 2 per cent to 40 per cent and tin content from 0.2 per cent to 3 per cent. This alloy is used to make electrical connectors, corrosion resistant mechanical products, springs, marine hardware, corrosion resistant screw machine parts, pump shafts and fasteners.
Tin Brass have a good cold workability and have great casting and fording ability. They are moderate in strength and corrosion resistance. However, it is a good conductor of heat and electricity. Brass is also modified by adding lead, tin and nickel for specialized use in marine applications. This alloy group is known by several names such as ounce metal, composition bronze and valve metal.
Aluminium bronze is an alloy of copper, zinc and aluminium. The alloy exhibits exceptional corrosion resistance characteristics, strength and resistance to wear and tear. They have good casting and forging ability. The corrosion characteristic of the alloy depends on the aluminium content.
Aluminium bronze containing 5 per cent to 12 per cent of aluminium have high corrosion resistance and high temperature oxidation. They are used in manufacturing hardware that comes in constant contact with seawater such as marine hardware and valve components, shafts and pumps for handling sea water, non-oxidising acids, sour mine water and industrial process fluids.
Aluminium bronze have exceptional quality to resist mechanical abrasions and chemical affects of sulphite solutions. Due to these characteristics, this alloy is used for blades and beater bars in wood pulp machines.
Nickel Silvers are also known as Nickel Brasses. They contain copper, zinc and nickel. They are mostly used in making handling equipment for food and beverage products, electroplated tableware, musical instruments, optical and photographic equipment and decorative hardware.
These alloys do not contain silver. However, they get their name from its attractive silver lustre. It has moderate to high strength and have a good resistance to corrosion. C75200 and C77000 are the most common nickel silvers. They have good corrosion resistance in fresh as well as seawater. This is due to high nickel content in these alloys.
Phosphorous Bronze are also known as tin bronze. They are alloys of copper, tin and phosphorous. They contain 0.5 per cent to 11 per cent tin and 0.01 to 0.35 per cent phosphorous. While tin helps in improving the strength and corrosion resistance of the metal, phosphorous improves the stiffness and the resistance to wear. These alloys have good resistance to seawater and most of the non-oxidizing acids with the exception of hydrochloric acid.
Phosphorous Bronze have high corrosion resistance, good soldering ability and formability, fatigue resistance, and exceptional spring qualities. Their prime utilization is in manufacturing of electrical products. Spring washers, bellows and diaphragms also use these alloys.
COPPER NICKEL ALLOYS
Copper nickel alloys have excellent resistance to corrosion. The common copper-nickel alloys are 70/30 and 90/10. These alloys are economical and are widely used in chemical industry. These alloys are superior to copper and its other alloys that resist corrosion and acid attacks. a defined composition of copper-nickel alloy is used in manufacturing of ship’s hull. This is to ensure that the hull does not corrode in seawater and reduction in adhesion to marine life