Class 10 Exam  >  Class 10 Notes  >  Chemistry for GCSE/IGCSE  >  Extraction of Aluminium from Bauxite

Extraction of Aluminium from Bauxite | Chemistry for GCSE/IGCSE - Class 10 PDF Download

Extraction of Aluminium from Bauxite

  • Aluminium is a reactive metal, positioned above carbon in the reactivity series.
  • Bauxite is the primary ore, containing aluminum oxide.
  • Due to aluminum's higher reactivity compared to carbon, it cannot be extracted by carbon reduction.
  • Instead, the extraction of aluminum is achieved through electrolysis.

Diagram showing the extraction of aluminium by electrolysis:
Extraction of Aluminium from Bauxite | Chemistry for GCSE/IGCSE - Class 10

Question for Extraction of Aluminium from Bauxite
Try yourself:
How is aluminium extracted from bauxite?
View Solution

The Process of Aluminium Extraction by Electrolysis

  • Bauxite undergoes a purification process to yield aluminium oxide (Al2O3)

Dissolving Aluminium Oxide in Molten Cryolite

  • Aluminium oxide is dissolved in molten cryolite due to its high melting point above 2000°C, which is energy-intensive and costly
  • The resulting mixture with cryolite lowers the overall melting point without affecting the reaction

Electrolysis Process

  • The mixture is placed in an electrolysis cell constructed from steel and lined with graphite
  • Graphite acts as the negative electrode while large graphite blocks serve as the positive electrodes
  • At the cathode, aluminium ions undergo reduction, forming molten aluminium at the cell's base
  • Periodically, the molten aluminium is extracted, and fresh aluminium oxide is introduced into the cell

Aluminium Extraction Process

  • Aluminium ions undergo reduction by gaining electrons.
  • Molten aluminium is formed at the bottom of the cell.
  • The molten aluminium is periodically siphoned off, and fresh aluminium oxide is introduced into the cell.

Reduction Process at the Anode

  • At the anode (positive electrode), oxide ions lose electrons through oxidation.
  • Oxygen is generated at the anode:
    Al3+ + 3e- → Al

Overall Reaction Equation

  • The overall reaction is represented as: 2Al2O3 → 4Al + 3O2

Role of Graphite Anodes

  • The carbon in the graphite anodes reacts with the oxygen produced, forming CO2.
    C(s) + O2(g) → CO2(g)
  • As a consequence, the anode gradually wears out and necessitates regular replacement.
  • This extraction process demands a substantial amount of electricity, leading to significant expenses.
The document Extraction of Aluminium from Bauxite | Chemistry for GCSE/IGCSE - Class 10 is a part of the Class 10 Course Chemistry for GCSE/IGCSE.
All you need of Class 10 at this link: Class 10
71 videos|147 docs|61 tests

FAQs on Extraction of Aluminium from Bauxite - Chemistry for GCSE/IGCSE - Class 10

1. How is aluminium extracted from bauxite?
Ans. Aluminium is extracted from bauxite through a process called electrolysis. First, bauxite ore is purified to produce alumina. Then, alumina is dissolved in molten cryolite and electrolyzed to extract aluminium metal.
2. What is the role of electrolysis in the extraction of aluminium from bauxite?
Ans. Electrolysis is used in the extraction of aluminium from bauxite to break down the alumina into aluminium and oxygen. This process requires a large amount of electricity and is conducted in a specialized electrolytic cell.
3. Why is bauxite the main source of aluminium extraction?
Ans. Bauxite is the main source of aluminium extraction because it contains a high concentration of alumina (aluminium oxide). This makes it an economically viable source for obtaining aluminium metal.
4. What are the environmental impacts of extracting aluminium from bauxite?
Ans. The extraction of aluminium from bauxite can have environmental impacts such as deforestation, habitat destruction, and water pollution. The process also requires a significant amount of energy, leading to greenhouse gas emissions.
5. How is the quality of extracted aluminium from bauxite ensured?
Ans. The quality of extracted aluminium from bauxite is ensured through rigorous refining processes to remove impurities. Quality control measures are in place throughout the extraction and purification process to ensure the final product meets industry standards.
Related Searches

Objective type Questions

,

Extra Questions

,

past year papers

,

Summary

,

mock tests for examination

,

MCQs

,

Extraction of Aluminium from Bauxite | Chemistry for GCSE/IGCSE - Class 10

,

study material

,

practice quizzes

,

shortcuts and tricks

,

Extraction of Aluminium from Bauxite | Chemistry for GCSE/IGCSE - Class 10

,

Sample Paper

,

Extraction of Aluminium from Bauxite | Chemistry for GCSE/IGCSE - Class 10

,

video lectures

,

ppt

,

pdf

,

Free

,

Semester Notes

,

Exam

,

Viva Questions

,

Previous Year Questions with Solutions

,

Important questions

;