Copper was introduced to the London Stock Exchange as far back as 1877, i.e. only one year after the birth of the LME. Even then the copper industry had recognized very quickly the London Metal Exchange, as its international evaluation mechanism. This role is still in place and the continued success of the copper futures contract, in fact today about 94% of all copper futures trading is done on the LME.
Specific characteristics of the copper futures contract
Contract: Copper Grade A
Lot Size: 25 tons (with a tolerance of +/-2)
Margin per Lot: $ 11,375
Forms: Grade A cathodes conforms to BSEN 1978: 1998
Quote: USD
The copper is a chemical element with the atomic number 29. Its symbol is CU.
In all likelihood, copper is the metal that mankind uses the longest: objects have been found dated copper 8700 BC. The ancient Greeks called it Chalkos, hence the prefix calco-adopted by modern geologists and chemists to designate certain minerals containing copper. His Italian name instead comes from the Latin spoken aramen (already attested word in 950) for the late aeramen, a derivative of the Latin aes entry which means copper, bronze and is a conserved name in other languages of Indo-European origin.
Only later replaced (Pliny) from the word cuprum = copper, bronze of Cyprus. It is from this word that derives the chemical symbol of the element, because in Roman times the bulk of copper was mined from the island of Cyprus, which was underlined by the term aes Cyprium = copper, bronze of Cyprus.
In Roman times there was no difference between the pure copper and bronze, its most important League.
Features
Copper is a pinkish or reddish metal (copper and gold are the only two coloured metals in nature), to very high electrical and thermal conductivity, exceeded only by those of silver; It is very resistant to corrosion and is not magnetic. Is easily machinable, extremely ductile and malleable; can be easily recycled and scrap have a high salvage value; combined with other metals to form numerous metallic alloys (it is estimated that at least 400), the most common are bronze and brass; among others, the Cupronickel and icuprallumini (also known as aluminum bronzes).
Also copper is bacteriostatic, which fights the proliferation of bacteria on its surface.
The two most common are of oxidation of copper are +1 ( cuprousion, Cu+1) and +2 ( copper (ii)ion, Cu+2).
Applications
For its copper is widely used in plumbing systems in plumbing fixtures, nautical equipment, in electrical engineering and electronics, in body and in architecture, coinage, craft and gift items, transport, construction and many other industries. The most common uses are:
- Electric wires and cables in the windings of electric motors and electromagnets and electromechanical relays.
- Pipes;
- Handles, knobs and other furniture finishes;
- sculpture: the statue of liberty, for example, contains 81.3 tonnes of copper;
- Parts of switches and electric current collectors;
- In alloys for the minting of coins;
- In the kitchen, to make frying pans and other Cookware.
- Most of table cutlery contains a percentage of copper;
- Sterling Silver, if it must be used at the table, must contain a few percent copper.
- As part of ceramics, and in the form of salts for colouring the glass;
- Musical instruments, especially brass instruments;
- In hospitals as bacteriostatic surface
- On submerged ships external parts to prevent marine molluscs and mussels sticking;
- The verdigris (copper (II) sulfate) is used as a poison and to purify the water.
Copper, pure and reduced in wires, finds its major application for the production and use of electricity (but not for the carriage: suspended cables of electrodes at medium and high voltage are not copper but aluminum, due to the increased mechanical resistance offered by this metal) and in the manufacture of printed circuit boards for the electronics.
In architecture by copper is used to make roofs and gutters, flashings, roof downspouts and other metal items. This metal is valued for its color, which changes over time when exposed to atmospheric agents: first darkens, until it becomes dark brown, then gradually becomes green oxidation.
Copper pipes are used to carry drinking water, fuel gases, medical gases, water for heating and air conditioning and refrigeration fluids; in fact copper is impermeable to gas, is easily foldable, resists corrosion and does not age when exposed to solar radiation. Thanks to its excellent thermal conductivity is one of the materials that make more efficient heat exchange: for this you use in heat exchangers, solar panels and wall radiant panels and floors.
Copper is widely used by craftsmen, artists and designers for its color and its easy processability making it suitable for many ornamental uses: you can easily obtain plates, frames, furniture and medals.
Copper is used for minting coins since antiquity: already Servant Tullio (IV century. BC) ordered to Mint copper coins, the "pecuniae". Nowadays the coins of 10, 20 and 50 cents and 1 and 2 euros are copper alloy, while those from 1, 2 and 5 cents are simply coppered steel externally.
An automobile may contain, depending on the model, from 15 to 28 kg of copper, which lie mostly in the cables and electrical equipment.
Copper, together with aluminium and zinc, is also used in advanced applications, as for example in Shape memory alloys, which take two different forms depending on whether they are above or below a certain temperature. Another application is in the field of superconductivity. in high-temperature superconducting materials the superconductivity is often due to the existence of Atomic planes of copper and oxygen.
History
Copper was already known to some of the oldest civilization of which we have evidence, the history of its use it is estimated at least 10,000 years old. Copper jewel dated around 8700 BC was found in the North of Iraq. Signs of copper refining activity from its mineral oxide (malachite and azurite) date back to 5000 BC, a thousand years earlier than those relating to the use of gold.
Copper and bronze artifacts of Sumerian origin were found in city sites dating back to 3000 B.C. and at the same time are pieces produced with copper and tin alloy by the ancient Egyptians. A pyramid has a drain pipe system copper alloy of approximately 5000 years old. The use of copper in ancient China dates back to 2000 BC, whose bronze production reaches excellence around 1200 BC.
Brass, an alloy of copper and zinc, was already known to the ancient Greeks and was used extensively by the Romans.
Copper was associated with the goddess Venus in mythology and Alchemy due to its sleek, its use in the manufacture of mirrors and for its main mining area, the island of Cyprus. The symbol used by alchemists to represent copper is identical to that used by astrologers to represent the planet Venus.
Production
Production processes to switch from pure metal ore, described later, regarding the case of sulfur minerals, which are more available. After miningextraction , minerals are crushed and ground to get a size range suitable for subsequent stages, where they separate the aggregates from the copper-rich fractions. Through the flotation emulsion powders with liquids surfactants are put into large pools from which you remove the foamy copper-rich surface still tied sulfur. You will get then of sludge, which are dried and concentrated in the next steps: first mechanically (concentration) and then thermally (roasting). Into the oven through air or oxygen blowing, you get the formation of gaseous so2 that separates from the liquid metal; at the same time the addition of silicon allows the Elimination of iron: the slag, composed of silicates, floats and is removed. The thermal refining continues through further oxygen or air blowing; Since oxidizes partly also the bathroom, we proceed with the pinaggio, which is to put a green stem that, burning, releases reducing gas and steam. To achieve maximum purity of copper, it is necessary to make an electrolytic refining: copper is dissolved in a tank containing a conductive solution and is selectively deposited on the cathode: less noble metals are present in solution, noble ones fall. The cathodes obtained consist of 99.97% pure copper, slabs of 96 cm x 95 cm x 1 cm, weighing about 100 kg; I am a raw merchantable goods stock exchanges in New York, London and Shanghai. Chemical specification for electrolytic copper is ASTM B 115-00. The electrolytic copper thus obtained is not yet ready to be worked directly, it must be recast into billets, plates or rods, from which plastic manufacturing various semi-finished products such as wires, tubes, rods, strips, plates, etc.
We must add that an increasingly large percentage of copper mines exploit biotechnology. The mineral is fractured and put into tanks where it is pumped water enriched with bacteria, thiobacillus ferroxidans and thiobacillus thiooxidans. These microbes oxidize the copper sulfide (insoluble in water) and transformed into sulphate (soluble), obtaining energy for their vital functions. This system allows considerable energy savings compared to traditional extraction (up to 30%) and non-free gases into the atmosphere.
Precautions
All copper compounds should be considered toxic, unless otherwise specified. Copper metallic, powder is flammable. 30 grams of copper sulfate is potentially lethal for humans. Dissolved in drinking water at concentrations greater than 1 mg/L can stain clothes and items washed with it. The maximum suggested copper in drinking water varies depending on the source, but is typically between 1.5 and 2 mg/L. The total daily dose following from DRI tolerable upper intake level is 10 mg daily.