Aluminum

Aluminum is a silvery white member of boron group of chemical elements. It has Al as a symbol, and its atomic number is 13. Aluminum is not soluble in water under normal circumstances.
Aluminum considered as the third most abundant element, and the most abundant metal. It makes up about 8% by weight of the Earth's solid surface. Aluminum metal is a very reactive metal .It is found combined in 270 different minerals. Aluminum History
In 1761, Guyton de Morveau suggested calling the base alum alumina. In 1808, Humphry Davy identifies the existence of a metal base of alum.
The metal was first produced in 1825 in an impure form by physicist and chemist Hans Christian Ørsted. He react anhydrous aluminum chloride with potassium amalgam, yielding a lump of metal looking similar to tin. Friedrich Wöhler was aware of these experiments and cited them, but after redoing the experiments of Ørsted he concluded that the metal was pure potassium. He conducted a similar experiment in 1827 by mixing anhydrous aluminum chloride with potassium and yielded aluminum. Aluminum Characteristics
There are many characteristics of aluminum, and here i will talk about two types of aluminum characteristics:-

1- Physical characteristics:
Aluminum is a soft, durable, lightweight, and malleable metal with appearance ranging from silvery to dull gray, depending on the surface roughness. A fresh film of aluminum film serves as a good of visible light and an excellent reflector of medium and far infrared radiation. The yield strength of pure aluminum is between 7 and 11 MPa. Aluminum has 1/3 the density of steel. Aluminum atoms are arranged in a face-centered cubic structure.
Aluminum is one of the few metals that retain full silvery reflectance in powdered form, making it an important component of silver-colored paints.
Aluminum is a good thermal and electrical conductor, having 59% the conductivity of copper, both thermal and electrical.

2- Natural occurrence:
Aluminum is the most abundant metallic element and the third most abundant of all elements because of its strong affinity to oxygen, it is almost never found in the elemental state; instead it is found in oxides or silicates. Feldspars, the most common group of minerals in the Earth's crust, are aluminosilicates. It also occurs in the minerals beryl, cryolite, garnet, spinel and turquoise. Impurities in Al2O3, such as chromium or iron yield the gemstones ruby and sapphire.
Although aluminum is a common and widespread element, the common aluminum minerals are not economic sources of the metal. Almost all metallic aluminum is produced from the ore bauxite. Bauxite occurs as a weathering product of low iron in tropical climatic conditions. Large deposits of bauxite occur in Australia, Brazil, Guinea and Jamaica and the primary mining areas for the ore are in Australia, Brazil, China, India, Guinea, Indonesia, Jamaica, Russia and Surinam.

Production and refinement of aluminum

Aluminum forms strong chemical bonds with oxygen. Compared to most other metals, it is difficult to extract from ore, such as bauxite, due to the energy required to reduce aluminum oxide (Al2O3). For example, direct reduction with carbon, as is used to produce iron, is not chemically possible because aluminum is a stronger reducing agent than carbon. Hall-Héroult process, the major industrial process for aluminum extraction. Because of the high melting point of aluminum oxide (2,000 °C) the pure metal is extracted by electrolysis. In this process, aluminum oxide is dissolved in molten cryolite with calcium fluoride and then reduced to aluminium at a temperature between 950 and 980 °C. Cryolite is a chemical compound of aluminum and sodium fluorides. The Wöhler process is replaced by the electrolyte process. Both of the electrodes used in the electrolysis of aluminum oxide are made of carbon. Once the refined alumina is dissolved in the electrolyte, the ions are free to move around. The reaction at the cathode is: Al3+ + 3 e− → Al
Here the aluminum ion is being reduced. The aluminum metal then sinks to the bottom and tapped off.
At the anode, oxygen is formed:
2 O2− → O2 + 4 e−
The anodes in a reduction cell must be replaced regularly. The cathodes do erode, mainly to electrochemical processes and metal movement.
The Hall-Héroult process consumes a lot of energy by aluminum electrolysis. The Hall-Heroult process produces aluminum with a purity of 99%. Electric power represents about 20% to 40% of the cost of producing aluminum. Smelters try to search for a place where electric power is both plentiful and inexpensive. The world's largest smelters of alumina are People's Republic of China, Russia, and Quebec and British Columbia in Canada. Aluminum Applications (General Use)
There are many applications and general uses of aluminum and i will mention some of it.
Aluminum is the most widely used non-ferrous metal. Aluminum is almost always alloyed, which markedly improves its mechanical properties, especially when tempered. For example, the common aluminum foils and cans are alloys of 92% to 99% aluminum.
Some of the many uses for aluminum metal are in:
- Transportation (automobiles, aircraft, trucks, railway cars, marine vessels, bicycles).
- Packaging (cans, foil,).
- Construction (windows, doors, siding, building wire,).
- Street lighting poles, sailing ship masts, walking poles.
- Heat sinks for electronic appliances such as transistors and CPUs.
- Powdered aluminum is used in paint.
- Aluminum can be reacted with hydrochloric acid or with sodium hydroxide to produce hydrogen gas.
- Some guitar models sports aluminum diamond plates on the surface of the instruments.

Aluminum Health Concerns
Aluminum has no known function in biology. The extremely low acute toxicity, the health effects of aluminum are of interest in view of the widespread occurrence of the element in the environment and in commerce.
Some toxicity can be traced to deposition in bone and the central nervous system, which is particularly increased in patients with reduced renal function. Because aluminum competes with calcium for absorption, increased amounts of aluminum may reduce skeletal mineralization observed in preterm infants and infants with growth retardation. In very high doses, aluminum can cause neurotoxicity, and is associated with altered function of the blood-brain barrier. A small percentage of people are allergic to aluminum and experience contact dermatitis, digestive disorders, vomiting or other symptoms upon contact or ingestion of products containing aluminum. In those without allergies, aluminum is not as toxic as heavy metals, but there is evidence of some toxicity if it is consumed in excessive amounts. Resources:- 1- en.wikipedia.org/wiki/aluminum 2- www.world-aluminum.org 3- www.aluminum-dubai.com