
139Reformulation of Potline Control
Alumina Feeding and Sludge Formation
Sludge buildup in pots can be tracked quite adequately using the auto-
mation system that records every shot of alumina added to each pot over
a long period of time. Over a period, such as three to six months, the total
amount of alumina fed to any pot can be compared with the metal pro-
duction and the measured shot weight to conrm the difference between
the amount of alumina fed and the amount used to make aluminium
(Faraday’s law applies, dictating that 1.90 to 1.92 kg of alumina is used up
for every kg of aluminum produced).
In fact, the CuSum (cumulative sum) of alumi ...