Making aluminium

Keywords and big picture starter Bauxite, Aluminium oxide, graphite, cryolite, electricity, molten, malleable, strong, low density and unreactive. Take a look at the bauxite ore and aluminium foil shown on the desk think of 5 facts and uses about aluminium Use the keywords above to help

THE ELECTROLYSIS OF ALUMINIUM FROM ALUMINIUM OXIDE L.O. Explain with diagrams – the extraction of aluminium from bauxite Evaluate the importance of conditions needed for extraction of aluminium

Explain with diagrams – the extraction of aluminium from bauxite Add as much detail to the picture of this electrolytic cell to explain how aluminium is extracted What do the red, grey and black areas represent? What do the yellow areas represent? What is being oxidised? 4. What is being reduced? 5. Which way will electrons flow and why? 6. How can you summarise this process using half equations

start Explain with diagrams – the extraction of aluminium from bauxite What do the red, grey and black areas represent? What do the yellow areas represent? What is being oxidised? 4. What is being reduced? 5. Which way will electrons flow and why? 6. How can you summarise this process using half equations Explain with diagrams – the extraction of aluminium from bauxite start

EXTRACTION OF ALUMINIUM Help 1 THE CELL CONSISTS OF A

EXTRACTION OF ALUMINIUM Help 2 CARBON ANODE THE CELL CONSISTS OF A CARBON ANODE

EXTRACTION OF ALUMINIUM Help 3 STEEL CATHODE CARBON LINING THE CELL CONSISTS OF A CARBON LINED STEEL CATHODE (iron and carbon)

MOLTEN ALUMINA and CRYOLITE EXTRACTION OF ALUMINIUM Help 4 MOLTEN ALUMINA and CRYOLITE ALUMINA IS DISSOLVED IN MOLTEN CRYOLITE Na3AlF6 SAVES ENERGY - the mixture melts at a lower temperature

MOLTEN ALUMINA and CRYOLITE EXTRACTION OF ALUMINIUM Help 5 MOLTEN ALUMINA and CRYOLITE ALUMINA IS DISSOLVED IN MOLTEN CRYOLITE Na3AlF6 aluminium and oxide ions are now free to move

EXTRACTION OF ALUMINIUM Help 6 POSITIVE ALUMINIUM IONS ARE ATTRACTED TO THE NEGATIVE CATHODE CARBON CATHODE Al3+ + 3e- Al EACH ION PICKS UP 3 ELECTRONS AND IS DISCHARGED

O2- O + 2e- NEGATIVE OXIDE IONS ARE ATTRACTED TO THE POSITIVE ANODE EXTRACTION OF ALUMINIUM Help 7 NEGATIVE OXIDE IONS ARE ATTRACTED TO THE POSITIVE ANODE CARBON ANODE O2- O + 2e- EACH ION GIVES UP 2 ELECTRONS AND IS DISCHARGED

Electrons will flow from most reactive to least reactive electrode EXTRACTION OF ALUMINIUM Help 8 ELECTRONS CARBON ANODE CARBON CATHODE Electrons will flow from most reactive to least reactive electrode

EXTRACTION OF ALUMINIUM Help 9 ELECTRONS OXIDATION (LOSS OF ELECTRONS) TAKES PLACE AT THE ANODE CARBON ANODE ANODE OXIDATION

EXTRACTION OF ALUMINIUM Help10 ELECTRONS OXIDATION (LOSS OF ELECTRONS) TAKES PLACE AT THE ANODE REDUCTION (GAIN OF ELECTRONS) TAKES PLACE AT THE CATHODE CARBON CATHODE ANODE OXIDATION CATHODE REDUCTION

Electrons will flow from most reactive to least reactive electrode finish ELECTRONS OXIDATION (LOSS OF ELECTRONS) TAKES PLACE AT THE ANODE CARBON ANODE REDUCTION (GAIN OF ELECTRONS) TAKES PLACE AT THE CATHODE CARBON CATHODE ANODE 2O2- O2 + 4e- OXIDATION CATHODE Al3+ + 3e- Al REDUCTION ALUMINA IS DISSOLVED IN MOLTEN CRYOLITE Na3AlF6 aluminium and oxide ions are now free to move SAVES ENERGY - the mixture melts at a lower temperature

THE CARBON ANODES REACT WITH THE OXYGEN TO PRODUCE CARBON DIOXIDE Evaluate the importance of conditions needed for extraction of aluminium BAUXITE aluminium ore Bauxite contains alumina (Al2O3 aluminium oxide) plus impurities such as iron oxide – it is purified before use. CRYOLITE Aluminium oxide Al2O3 has a very high melting point. Adding cryolite Na3 AlF6 lowers the melting point and saves energy. THE CARBON ANODES REACT WITH THE OXYGEN TO PRODUCE CARBON DIOXIDE THE CARBON ANODES HAVE TO BE REPLACED AT REGULAR INTERVALS, THUS ADDING TO THE COST OF THE EXTRACTION PROCESS

THE IMPORTANCE OF ALUMINIUM USES OF ALUMINIUM THE IMPORTANCE OF ALUMINIUM LOW DENSITY AND OVERHEAD CABLES ELECTRICAL CONDUCTIVITY LOW DENSITY AIRCRAFT BODIES needs to be an alloyed with other metals for extra strength GOOD HEAT CONDUCTIVITY SAUCEPANS

THE IMPORTANCE OF ALUMINIUM USES OF ALUMINIUM THE IMPORTANCE OF ALUMINIUM LOW DENSITY AND OVERHEAD CABLES ELECTRICAL CONDUCTIVITY LOW DENSITY AIRCRAFT BODIES needs to be an alloyed with other metals for extra strength GOOD HEAT CONDUCTIVITY SAUCEPANS Syllabus wants you to quote theses uses and reasons

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