Method of controlling aluminum reduction cell with prebaked anodes

Abstract

In the method of controlling an aluminum reduction cell with prebaked anodes an area of reduced alumina concentration is defined in the cell by measuring the present electrical current values in at least one anode of the cell independently of other anodes. Upon detection of the electric current reduction in this anode, the rate of alumina feeding is increased into a bath of the cell at the area of reduced alumina concentration.

1 . A method of controlling an aluminum reduction cell with prebaked anodes, said method comprising the steps of: 
 measuring present electrical current values;    comparing said present electrical current values with predetermined values thereof;    maintaining said present electrical current values within preset limits by regulating amount of alumina charged into the cell;    wherein an area of reduced alumina concentration is defined in the cell by measuring the present electrical current values associated with at least one anode of the cell independently of other anodes; and    upon detection of electric current reduction at said at least one anode the rate of alumina feeding is increased into a bath of the cell at said area of reduced alumina concentration.    
   
   
       2 . A method of  claim 1 , wherein said electric current reduction in said at least one anode is determined by comparing the electric current in said at least one anode with the electric current in other anodes of said cell.  
   
   
       3 . A method of  claim 1 , wherein said area of reduced alumina concentration is identified by verifying the rate of increase of back EMF value in each said anode.  
   
   
       4 . A method of  claim 2 , wherein said value of the back EMF is determined by reviewing changes of the total electric current passing through all said anodes of the cell.  
   
   
       5 . The method of  claim 1 , wherein said at least one anode comprises a group of neighboring anodes, and said group of neighboring anodes is associated with a respective alumina feeder.  
   
   
       6 . The method of  claim 1 , wherein said increased rate of feeding of alumina into the bath of the cell is terminated upon elimination of said area having reduced alumna concentration.