Potrooms
The potrooms house 480 pots altogether, and in those pots the aluminum is produced. The pots contain a liquid cryolite, called electrolyte, from which aluminium is produced by electrolysis. The alumina is disolved in the electrolyte and for electrolysis to take place, an electric current must be sent through the pot. Carbon anodes conduct electricity to the pot, where the current runs through the electrolyte and leaves the pot through cathodes at the bottom. When the current is sent through the electrolyte, the alumina molecule breaks down into its elements: - aluminium and oxygen (see picture). The aluminium settles at the bottom of the pot, whereas the oxygen moves up toward the anodes, oxidizes their carbon and creates CO2. The anodes have to be replaced about every 30 days. Remains of used anodes are sent abroad for recycling into new anodes.Every two days, aluminium is tapped from the pots. An employee in a tapping vehicle opens the pot, puts a suction pipe down to the bottom and sucks molten aluminium into a tapping crucible. The molten aluminium is thus transported to the casthouse.