It relies on a crust of solid cryolite as thermal insulation. A fluoride is used to lower the melting temperature of molten cryolite beneath the crust. The entire mixture is electrolyzed, and the carbon anode is oxidized to carbon dioxide as the end product collects in liquid form at the bottom of the tank. For 10 points—name this process discovered by an American and a Frenchman at the same time 
It relies on a crust of solid cryolite as thermal insulation. A fluoride is used to lower the melting temperature of molten cryolite beneath the crust. The entire mixture is electrolyzed, and the carbon anode is oxidized to carbon dioxide as the end product collects in liquid form at the bottom of the tank. For 10 points—name this process discovered by an American and a Frenchman at the same time in 1866, the major method for producing aluminum.
It relies on a crust of solid cryolite as thermal insulation.
{Hall-Heroult} process [accept either or both of the names]