Arrangement of anode for utilisation in an electrolysis cell

Abstract

The invention relates to an arrangement of anode for utilisation in an electrolysis cell for production of aluminium metal from an aluminium containing component in a molten salt electrolyte, in which the aluminium containing component mainly is alumina and the molten salt electrolyte is based on mixtures of NaF and AIF 3 and CaF 2 , and possibly alkaline and alkaline earth halides. More specific it relates to improvements of anodes useful for retrofit of existing electrolysis cells, in which the anodes remains inert during operation. The anode is characterised by being shaped in a manner to increase the area of the electroactive surface. Several examples of such designs are shown. The anode is useful for utilisation in retrolit of existing electrolysis cells of Hall-Hèroult design for aluminium production.

1 . Arrangement of anode for use in an electrolysis cell for production of aluminium metal from an aluminium containing component in a molten salt, where the aluminium containing component mainly consist of alumina and the molten salt electrolyte is based on mixtures of NaF and AIF 3  and CaF 2 , and possibly alkaline and alkaline earth halides, in which the anode principally remains inert (non-consumable) in the process; 
 characterised by    that the anode is shaped so that its working surface becomes larger than its cross sectional area.    
     
     
         2 . The arrangement of the anode in  claim 1;   characterised by    that the anode surface is increased by means of forming grooves, saw tooths, peaks and valleys, sinus curves, protruding shapes, pyramids, etc. on the electroactive surface of the anode.    
     
     
         3 . The arrangement of the anode in  claim 1;   characterised by    forming several, and at least one, grooves, saw tooths, peaks and valleys, sinus curves, protruding shapes, pyramids, etc. on the electroactive surface of the anode, where different wave lengths (frequencies) and amplitudes can be used on top of each other (superimposed)    
     
     
         4 . The arrangement of the anode in  claim 1;   characterised by    that the anode is designed so that its electrical conductivity in the outer layer(s) is of the same order of magnitude as in the electrolyte.    
     
     
         5 . The arrangement of the anode in one or more of the above mentioned claims; 
 characterised by    the anode is being prepared for retrofit of existing electrolysis cells of Hall-Hèroult design for aluminium production.