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brick. The crew then installs the carbon sidewall blocks around
the sides of the shell to cover the area from the cathode blocks
to the top of the shell. Finally, the crew rams paste around and
between the cathode blocks to create a smooth, solid cell cavity.
After the lining is replaced, the collector bars are
connected to a ring bus, the steel superstructure is reinstalled
above the cell, new anodes are hung from the superstructure, and
the cell shields are reinstalled over the shell. Finally, the
cell is reconnected to the pot line; however, the relined shell
is not operational until the replacement lining and cathode
blocks have "baked" for 48 hours. The average time for a cell to
be out of service for replacement of its lining is 15 days.
Unless otherwise noted, the 1992 and 1993 replacement costs
(including labor and allocable overhead) for the cell components
and the average useful life in years for each component are as
follows:
Component Cost Average Life
Cell lining 1$17,933 3.0
Cell cradle 5,583 226.4
Shell 10,084 353.8
Carbon anode 1,184 40.0
Anode assembly:
Copper rods 2,240 5.0
Steel stubs 423 1.0
Bolts 249 4.1
Nuts 14 0.5
Cast iron 13 0.3
Cell shield 580 10.4
Anode clamp 197 5.3
Flexible strap 2,166 13.0
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Last modified: May 25, 2011