The process was patented by William Hoopes, a chemist of the Aluminum Company of America (ALCOA), in 1925.
The cell used in this process consists of an iron tank lined with carbon at the bottom.
A molten alloy of copper, crude aluminium and silicon is used as the anode.
The middle layer consists of molten mixture of fluorides of sodium, aluminium and barium (cryolite + BaF2).
A set of graphite rods dipped in molten aluminium serve as the cathode.