Extraction of aluminium can be understood by :

Electrolytric reduction of `Al_(2) O_(3)` :
Electrolysis : `Al_(2) O_(3) + Cryolite + CaF_(2)`
Cathode : Carbon inside the `Fe` container
Anode : Graphite rods.
Coke power is spread over the molten electroltyte to.

Options

A. prevent the heat radiation from the surface
B. prevent the corrsion of graphite anode
C. prevent oxidation of molten aluminium by air
D. both (A) & (B)

Answer

D