Question

The electrochemical extraction of aluminum from bauxite ore involves

(A) the reaction of Al₂O₃ with coke (C) at a temperature > 2500 °C.

(B) the neutralization of aluminate solution by passing CO₂ gas to precipitate hydrated alumina (Al₂O₃·3H₂O).

(C) the dissolution of Al₂O₃ in hot aqueous NaOH.

(D) the electrolysis of Al₂O₃ mixed with Na₃AIF₆ to give Al and CO₂.

Answer 1

(B) the neutralization of aluminate solution by passing CO2 gas to precipitate hydrated alumina (Al₂O₃·3H₂O).

(C) the dissolution of Al₂O₃ in hot aqueous NaOH.

(D) the electrolysis of Al₂O₃ mixed with Na₃AIF₆ to give Al and CO₂.

→ During electrolysis of alumina, cryolite (Na₃AlF₆) and fluorspar (CaF₂) are added to decrease the melting point of alumina. 

→ Al metal is obtained at cathode while CO₂ releases at anode.