Vanalco, Inc., a Delaware S Corporation, Richard L. Smith, Tax Matters Person - Page 5




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          The Cell Lining Replacement                                                 
               The voltage of the cells is monitored to ensure that the               
          cells are operating properly.  When the voltage in a cell cannot            
          be maintained at a certain level or within a specified range, it            
          generally indicates that something is wrong with the cell lining.           
          In this circumstance, if all other attempts to restore the proper           
          operation of the cell fail, the cell will be bypassed and removed           
          from service to have its lining replaced.                                   
               When a cell ceases to operate properly and a sample of the             
          molten aluminum shows an iron content above a certain level, it             
          is most likely that the cell lining has eroded to expose the                
          steel collector bars or the shell.  At this point, the lining is            
          burned or eroded to the point where a substantial number of the             
          cathode blocks are no longer recognizable.  If the lining is not            
          replaced in this circumstance, the cell eventually will rupture             
          and molten metal will spill onto the floor.                                 
               The following materials make up the cell lining:  Cathode              
          blocks made of carbon,3 steel collector bars, refractory brick              
          made of silicate material, castable refractory, steel plate,                



               3Cathode blocks make up the bulk of the cell lining.  For              
          instance, each LCD cell requires 8 blocks that are 60 inches by             
          18 inches by 14 inches, 2 blocks that are 60 inches by 15 inches            
          by 14 inches, 1 block that is 60 inches by 17 inches by 14                  
          inches, 2 blocks that are 30 inches by 18 inches by 14 inches,              
          and 2 blocks that are 30 inches by 17 inches by 14 inches.                  




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Last modified: May 25, 2011