Bauxite Refining

Just like coal, bauxite is a sedimentary rock; it isn't a mineral but a rock that contains minerals. It is an aluminum ore mostly formed in weathered volcanic rocks. Bauxite is more of a rock and not a mineral because its contents are determined by the location where it is extracted. Bauxite is mostly mined through an open pit mining where the water is removed completely from the ore extracted. This results into aluminum oxide, otherwise known as alumina.

The common uses of bauxite include chemicals, cement, soda cans, face makeup, siding for most houses, dishwashers, and numerous other aluminum products. Being the most crucial aluminum ore, it largely consists of minerals diaspore ?-AlO(OH), boehmite ?-AlO(OH), and gibbsite, as well as iron oxides hematite and goethite, little traces of anatase TiO2 and clay mineral.

Mining and bauxite processing is easy. As mentioned above, mining is mostly through strip mining as it is largely found at the surface. Circa 95% of bauxite production in the world is refined into alumina first and then aluminum. The classification of bauxite is done based on their commercial application - abrasive, metallurgical, refractory, cement, and chemical.

Bauxite refining occurs when bauxite is heated together with sodium hydroxide under 150-200 ?C in pressure vessels. This process dissolves aluminum as aluminate. Red mud (ferruginous residue) is separated through the filtering process, the liquid is allowed to cool, it is seeded using fine grained aluminum hydroxide, and then pure gibbsite is precipitated. Heating ensues which converts the precipitated gibbsite into aluminium oxide. At around 1000?C, it is molten and cryolite is added as flux and reduced to metallic aluminium by an electrolytic process.

The process of conversion of bauxite to aluminum is known as the Bayer process. It is combined with lime, caustic soda, and steam to result into sodium aluminate liquor where the impurities will be filtered or even settled off the liquor and the hydrate will be precipitated off the whole mixture. The bonded water and moisture is removed from the alumina hydrate through calcination and the end product will be ready to be smelt into aluminum.

Note that bauxite refining can take place near the mining site or sometimes shipped as aluminum ore to different parts of the world to be refined. Bauxite is made up of 45-60% of aluminum oxide and 12-30% of water, among other impurities which, once it is refined, pure bauxite is derived.

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said:

Nice article dude

(: said:

helped me a lot with me school project. thanks bro (: (: (:

... said:

hahaah this helped with my school assinment too

:) said:

THANKS ! HELPED A LOT BRO :D lifesaver ! :)

said:

Thanks for poring some insight on bauxite refining. I have been doing a project at my school and this is going to help me build some more information for sure. The refining process seems so tough for sure.

said:

My uncle used to have a bauxite mine in his farmfield. Just recently the government took over the site for some factory requirements. We used to earn a lot selling the ores which is very pure mostly.

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