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insulation board, carbon sidewall blocks, carbon lining paste,
and various nuts and bolts.
Once it is determined that the cell lining must be replaced,
the cell is shunted from the pot line and the carbon anodes are
removed. The cell is allowed to cool for 20 hours, and then
water is added to further cool the cell and to soften the lining
materials. The steel superstructure and the cell shields are
removed next, and repairs, if required, are made to the
superstructure. The cell lining crew (the crew)4 then removes
the cooled, solidified electrolyte and aluminum metal from the
cell cavity, and the cell is dug with pot diggers to remove the
remaining cell lining. Once the lining has been removed, the
shell and shell cradle are taken to the shell repair area for any
necessary repairs.
A repaired shell and shell cradle are put in the vacant
place in the pot line, and the replacement lining is installed in
layers. First, the bottom of each shell is lined with two layers
of insulating block, and a layer of sheet metal is placed on top
of the insulating block to form a vapor barrier. Next, two
layers of heavy refractory fire brick are added on top of the
metal vapor barrier, and the cathode blocks with embedded steel
connector bars are placed in rows on top of the refractory fire
4Vanalco employs between 22 and 26 workers on the crew.
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Last modified: May 25, 2011