Essay on the Production of Aluminium

Aluminium is the 3rd most abundant element in the Earth’s crust and is present as 7.3% by mass. In nature it is only stable when bonded to other elements, particularly in the form of silicates and oxides as it is too reactive to occur free in nature. By 1808 its existence was first established and it took many years to release the metal from its ore and many more years to produce a viable, commercial production process. By 1886 Charles Hall discovered a cheap method of extracting aluminium from its ore.

Aluminium Extraction vs. Iron and Zinc Extraction

Aluminium extraction differs from that of other elements such as zinc and iron for a number of reasons, which all relate to its properties. Zinc and iron production is quite a similar process, whereby both procedures employ the use of a blast furnace in the presence of carbon (coke) and other reducing compounds to reduce the prepared ores into the element being purified. Aluminium ores are prepared by treatment with concentrated sodium hydroxide to produce aluminium oxide. This method is used as aluminium is amphoteric (reacts with acids and bases) but not other compounds are not so they remain insoluble (e.g. iron oxide). The blast furnace method is not employed for aluminium extraction because aluminium on its own is very reactive and when it forms compounds like aluminium oxide it is very stable. Therefore it is very difficult to reduce it using standard compounds normally used in extractions, even at very high temperatures. That is why the electrolysis method is used for aluminium extraction.

Aluminium Extraction

Aluminium is produced industrially through the electrolysis of molten aluminium oxide. The chief aluminium ore is termed bauxite and contains aluminium in the form of hydrated oxide (Al2O3.xH2O). Mines have been built all over the world …

Tags: aluminium, aluminium oxide, environment, extraction, greenhouse gas, production

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