Electrolysis

Electrolysis is the extraction of metals using a molten composition of a type of ore and its metallic components and a cathode and anode. An electrical current is passed through the solution and the positively charged ions get deposited at the cathode and negatively charged ions get deposited at the anode, leaving the excess amounts of minerals to sink to the bottom to be recycled or made waste of.

Bauxite is the ore that is the main source of aluminium. It consists of the minerals gibbsite, boehmite, diaspore, goethite, haematite, kaolonite, and anatase and few of these contain aluminium. Aluminium is a light weight, ductile, silvery white coloured metal that can resist corrosion. It is the third most common element in the Earth’s crust, making up 8.1%. It is found naturally as bauxite and is later refined into aluminium oxide, then to aluminium. It is used to make air craft, cutlery, packaging, etc. Its scientific symbol is Al, its atomic number is 13, its atomic weight is 26.9815 (4dp), its boiling point is 2520 degrees Celsius and weighs 2.699 grams per cubic cm.

All metals above carbon on the reactive series can only be extracted via electrolysis. Aluminium can only be extracted through electrolysis due to the fact that aluminium is above carbon in the reactivity series and therefore smelting using carbon is not strong enough to reduce the oxide in the ore.

First, bauxite is sent off to alumina refineries to make alumina or aluminium oxide using the bayer process, which includes digesting the bauxite in a 175 degrees Celsius solution of sodium hydroxide under pressure, adding lime to precipitate silica and then heating it at 960 degrees Celsius to decompose the aluminium hydroxide to aluminium oxide and it comes out as a fine white powder. From here it is sent off to a aluminium shelter where it undergoes the hall-heroult process in which the powder is dissolved in molten cryolite to lower its temperature for electrolysis. A mixture of cryolite, alumina and aluminium fluoride are electrolysed and molten aluminium gets deposited at the cathode.

Bauxite is the main ore of aluminium and three places where it can be mined in Australia are Weipa Queensland, Darling Range Western Australia, and Gove Northern Territory.

3 uses for aluminium in the current society include, the construction of aircraft, metal cutlery, and the construction of roofing for houses.

It is estimated that aluminium will run out in Australia in 2110, reason being that aluminium is widely used and Australia is one, if not the largest producer of aluminium on Earth and the metal is quite abundant being the 3^rd most common metal.

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If aluminium were to run out we would have to substitute steel in place of aluminium although it may not carry some of the properties of aluminium such as flexibility and malleability. It would also weigh more than usual but steel is the only thing that can come close to being a substitute for aluminium due to their many similarities.

Bibliographies:
http://en.wikipedia.org/wiki/Bauxite
http://en.wikipedia.org/wiki/Electrolysis
http://en.wikipedia.org/wiki/Aluminium
http://bauxite.world-aluminium.org/refining/process.html
http://en.wikipedia.org/wiki/Bayer_process
http://en.wikipedia.org/wiki/Hall%E2%80%93H%C3%A9roult_process
http://www.ukindemand.ac.uk/research/alternatives-steel-and-aluminium-construction