Bauxite is an ore which is used for the extraction of aluminium. Bauxite has provided almost all of the aluminium that has ever been produced. Although the United States has a few small bauxite deposits, it imports at least 99 per cent of the bauxite it uses. Aluminium metal is also a major imported commodity in the United States. Bauxite is not a mineral, it is a rock that is mostly made up of aluminium-bearing minerals. It is formed in a moist tropical or subtropical environment when laterite soils are extensively leached of silica and other soluble minerals.

What is bauxite?

The major material from which we obtain aluminium is bauxite. However, the process is complicated since it contains other components such as iron. Bauxite is an ore of aluminium; the bauxite formula is:

The ore is first crushed and then mixed with chemicals. These chemicals make the aluminium float to the top so that it can get drawn off from there. This aluminium goes through a drying process and gets collected as a powder. But, it is still an impure aluminium form so it goes into a furnace and is melted down; after that, the final impurities come to the top, floating as slag and get taken off from there, which leave the pure aluminium behind. This pure aluminium is then poured into moulds to produce ingots. Bauxite can be found around the equator easily.  Australia is one of the largest suppliers of bauxite in the world.

Why is bauxite used?

Bauxite is predominantly a metallic mineral with certain industrial uses. It is the only resource that can be utilised to make massive amounts of aluminium. Even though aluminium is the most prevalent metallic element in Earth’s crust, accounting for around 8%, it is frequently found in clays, soils, and rocks that cannot be extracted. Bauxite is a sedimentary rock that is the main source of the widely used metal aluminium.

Bauxite is a residual deposit formed by atmospheric agents from rocks containing aluminium. In tropical conditions, it contains hydrated alumina,  iron and titanium oxides, and small amounts of silica. Limestone and bauxite are the raw materials for high alumina cement. HA Cement contains 40% Al and lime each and 15 % iron oxides.

Main uses of bauxite

Metallurgy

1. Bauxite is the best material for making aluminium, and it is the only material used for the same purpose.
2. Several processes, such as the Bayer process and the Hall Heroult process, are involved in the extraction of aluminium from bauxite.
3. Once mined, aluminium and aluminium-based alloys are widely used in electronics, construction, vehicles, and even tools.

Industries

1. Bauxite is used in many industrial sectors. These are the chemical, refractory, abrasive, cement, steel and oil industries.
2. In chemicals: Alumina and bauxite are used to manufacture aluminium chemicals.
3. In refractory: Bauxite is used as a raw material for making several products.
4. Bauxite is the main constituent material in the aeroplane, electric, machinery, and civil tool-making industries.
5. It is also used as an adsorbent, a catalyst in various processes, as a desiccating agent, and in the manufacturing of dental cement.
6. In road aggregates and building materials: Lateritic bauxite is often used as a construction material when other materials are unavailable. Construction companies use calcined bauxite as an anti-skid road aggregate used in selected areas to prevent accidents.

Other Uses

1. Bauxite has limited uses but wide applications in papermaking, water purifying, and petroleum refining.
2. Additionally, bauxite is used in other sectors like the cosmetic industry. It is also used in the paint industry,  rubber, and plastic industries and so on.

Bauxite physical properties

Bauxite is typically a soft material with a Mohs hardness of 1 to 3. It has a pisolitic structure, an earthy sheen, and a specific gravity of 2.0 to 2.5 and ranges in colour from white to grey to reddish-brown. These properties aid in identifying bauxite, but they do not influence its value or application. This is because bauxite is almost always processed into a material with different physical properties than bauxite.

Conclusion

Bauxite is the main ore source of aluminium and is quite plentiful in Earth’s crust. Australia has large reserves and is one of the major exporters of bauxite. Over time, the reserves may be depleted as more is recycled worldwide, as it is cheap to produce new aluminium from waste. 

Many products are made from aluminium and may not yet have met their full potential. The world’s bauxite resources are adequate for decades of production at current rates. Instead of bauxite, other resources might be used to manufacture alumina. Using alternative techniques, clay minerals, alunite, anorthosite, power plant waste, and oil shale might create alumina at a greater cost.