What is the role of graphite rod in the electromellurgy of aluminium?

Explanation

`rarr` In The electrolytic reduction of alumina `b_(y)`Hall- Heroult process graphite rod acts as anode.
`rarr` At anode , `O_(2)` gas is liberated which reacts with the carbon of anode to from `CO_(2) ` gas . So these graphite rods are consumed slowly and need to be replaced from time to time.
`Al_(2)O_(3)hArr2Al^(+3)+3O^(-2)`
Cathode : `Al^(+3)+3e^(-)rarrAl`
Anode : `3O^(-2)rarr3[O]+6e^(-)`
`C_((s))+O_(2_((g)))rarrCO_(2_((g)))`