Oxygen gas reacts with the carbon anode (at elevated temperatures) to from carbon monoxide, which escapes as a gas. The liquid aluminum metal (m.p. 660.2 C) sinks to the bottom of the vessel, from which it can be drained from time to time during the procedure.
Aluminum is one of the most versatile metals known. It has a low density (2.7 g/cm3) and high tensile strength (that is, it can be stretched or drawn out). Aluminum is
Charles Martin Hall (1863-1914). American inventor. While Hall was an undergraduate at Oberlin college, he became interested in finding an inexpensive way to extract aluminum.