Which process is used to extract aluminium from its ore, bauxite?a)Pur...
The process used to extract aluminium from its ore, bauxite, is electrolytic extraction of bauxite.
Which process is used to extract aluminium from its ore, bauxite?a)Pur...
Extraction of Aluminium from Bauxite
Aluminium is primarily extracted from its ore, bauxite, through a process known as electrolytic extraction. This method is essential due to the chemical properties of aluminium, which make it highly reactive and, therefore, difficult to isolate from its compounds.
1. Purification of Bauxite
- The first step involves purifying bauxite to remove impurities such as iron oxides and silica.
- This is achieved through the Bayer process, where bauxite is crushed and treated with a hot solution of sodium hydroxide.
- The sodium hydroxide dissolves the aluminium oxide present in bauxite, forming soluble sodium aluminate, while the impurities remain undissolved.
2. Electrolytic Extraction
- The purified sodium aluminate is then subjected to electrolysis.
- The process occurs in an electrolytic cell where molten aluminium oxide (derived from the purified bauxite) is mixed with cryolite (Na3AlF6) to lower the melting point.
- Direct current electricity is passed through the molten mixture, causing the aluminium ions to migrate to the cathode (negative electrode) and reduce to form aluminium metal.
3. Reduction of Bauxite
- While the term "reduction" is often associated with the extraction of metals, in the context of bauxite extraction, it is specifically the electrolytic process that facilitates this reduction.
- Therefore, while reduction of bauxite does occur, the primary method of extraction utilized is electrolytic.
4. Oxidation of Bauxite
- This option is incorrect as oxidation does not play a role in the extraction of aluminium from bauxite.
In summary, the key process used to extract aluminium from bauxite is the electrolytic extraction, which is crucial for obtaining pure aluminium due to its highly reactive nature.