Potrooms
 
The Point Henry smelter operates three potlines - the longest measuring 410 m -which house a combined 368 smelting pots. The potrooms are the heart of the smelting process as it is here that the molten aluminium is produced.
 
In the potrooms, the alumina is fed into a large carbon or graphite lined steel smelting cell known as a pot.  The alumina is dissolved in molten cryolite, also known as aluminium fluoride or ‘bath’. 
 
A high electric current is passed through the pot at low voltage via the carbon anodes which enable the alumina solution to split into its components of aluminium and oxygen. The oxygen reacts directly with the carbon anode, which gets consumed to form carbon dioxide that bubbles away and the aluminium collects at the bottom of the pot. The electricity also maintains the temperature of the pot at about 950 degrees Celsius.   The aluminium is then siphoned from the bottom of the pot using a crucible and is then transferred to the Alcoa Australia Rolled Products ingot mill for casting.
 
Each pot at Point Henry produces around 1.4 tonne of aluminium a day.  The pot contains 24 carbon anodes and they are replaced every 22.5 days.

A cruicable siphoning molten aluminium

Click image to enlarge.


Anodes being placed in the smelting pots

Click image to enlarge.