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5
Potline Process Control Failure
Back onsite. The course was a distant memory. Rob was walking into Line
1 and looking at the familiar anode setting and tapping operations. They
seemed to be on time, plenty of anodes and crucibles out on room A, and the
PTM (pot tending machine) busy.
As he was walking through room B West, he noticed that there were some
low temperatures on the risers. These pots carried sludge most of the time
due to the alumina feeding system, and they needed temperatures in the 955
to 965°C range to keep it from solidifying on the cathode. On the way to his
ofce, he counted 26 out of 52 pots below 950°C.
“The guys are seei ...