Which among the following statement(s) is(are) true for the extraction of aluminium from bauxite?

A

Hydrated $$Al_2O_3$$ precipitates, when $$CO_2$$ is bubbled through a solution of sodium aluminate.

B

Addition of $$Na_3AlF_6$$ lowers the melting point of alumina.

C

$$CO_2$$ is evolved at the anode during electrolysis.

D

The cathode is a steel vessel with a lining of carbon.