Production of Aluminium using Bauxite

Bauxite is mainly used for the production of Aluminium. Let's understand why Bauxite is the correct answer and how it is used in the production process.

What is Bauxite?
Bauxite is a sedimentary rock that is primarily composed of aluminum hydroxide minerals along with other minerals such as iron oxides, silica, and clay. It is the main ore of aluminium and is formed through weathering and leaching of aluminum-rich rocks over millions of years.

Extraction of Aluminium from Bauxite
The extraction of aluminium from bauxite involves several steps, including mining, crushing, washing, digestion, precipitation, and calcination.

Mining:
Bauxite is mined from the earth's surface using open-pit mining techniques. The bauxite deposits are usually found near the surface, making them easily accessible for extraction.

Crushing and Washing:
After mining, the bauxite ore is crushed and washed to remove impurities such as clay and silica. This helps in improving the quality of the ore before further processing.

Digestion:
The crushed and washed bauxite ore is then mixed with a hot solution of sodium hydroxide (NaOH) in a process called digestion. This step dissolves the aluminium hydroxide minerals present in the bauxite, while impurities remain insoluble.

Precipitation:
The dissolved aluminium hydroxide is then precipitated out of the solution by cooling and filtering. This process separates the aluminium hydroxide from the impurities.

Calcination:
The precipitated aluminium hydroxide is then heated to high temperatures in a process called calcination. This converts the hydroxide into alumina (Al2O3), which is the main component used for further processing into aluminium metal.

Electrolysis:
After obtaining alumina, it is then subjected to electrolysis in a process called Hall-Héroult process. This process involves passing an electric current through a molten mixture of alumina and cryolite (Na3AlF6) to extract pure aluminium metal.

Conclusion
In conclusion, bauxite is mainly used for the production of aluminium. It is extracted from the earth's surface through mining and undergoes various processing steps to obtain alumina. The alumina is then further processed through electrolysis to obtain pure aluminium metal.