Photo AI
Aluminium is extracted from bauxite - Leaving Cert Chemistry - Question B - 2002
Question B
Aluminium is extracted from bauxite. (i) Where in Ireland is bauxite purified to produce alumina? (4) (ii) Outline the steps involved in the extraction of aluminum... show full transcript
Worked Solution & Example Answer:Aluminium is extracted from bauxite - Leaving Cert Chemistry - Question B - 2002
Step 1
Where in Ireland is bauxite purified to produce alumina?
Answer
Bauxite is purified to produce alumina in various locations in Ireland, including Aughinish, Shannon estuary, Limerick, Askeaton, and Foynes. These areas are known for processing bauxite to extract alumina, which is an important step in aluminum production.
Step 2
Outline the steps involved in the extraction of aluminum from bauxite, giving balanced chemical equations where relevant.
Answer
- Digestion: Bauxite, primarily composed of , is treated with sodium hydroxide ( ext{NaOH}) at high temperatures to create sodium aluminate:
ightarrow 2 ext{NaAlO}_2 + 4 ext{H}_2 ext{O}$$
- Clarification: The solution undergoes filtration to remove impurities, producing clear sodium aluminate:
ightarrow ext{Al(OH)}_3 + 2 ext{NaOH}$$
-
Separation: The aluminum hydroxide, ext{Al(OH)}_3, is recovered.
-
Calcination: This hydroxide is then heated (roasted) to remove water at approximately :
ightarrow 2 ext{NaOH} + ext{Al}_2 ext{O}_3 + 3 ext{H}_2 ext{O}$$
- Electrolysis: Finally, aluminum oxide, ext{Al}_2 ext{O}_3, is subjected to electrolysis in a molten electrolyte to produce aluminum metal.
Step 3
Give two reasons why it is preferable to produce aluminum by recycling rather than by extracting it from its ore.
Answer
-
Saves Energy: Recycling aluminum requires significantly less energy compared to extracting aluminum from bauxite, leading to lower carbon emissions and environmental impact.
-
Conservation of Resources: Recycling helps conserve natural resources by reducing the need for extensive mining and limits environmental damage associated with ore extraction.