Electrolytic reduction cell and collector bar

Abstract

An electrolytic reduction cell for the production of a metal is disclosed. The cell includes a plurality of collector bars ( 21 ). Each collector bar includes an elongated first section ( 27 ) that contacts the cathode ( 15 ) and at least one end section ( 29 ) that extends through one of the cell side walls ( 5 ) and is electrically connected to the electrical current carrier. The cell is characterised in that, for the purpose of controlling current distribution, the first section of each collector bar includes a core ( 31 ) of relatively high electrical conductivity material and an outer housing ( 33 ) of a more mechanically and chemically resistant material than the core material and the end section of each collector bar is formed from relatively low thermal conductivity material.

1 . An electrolytic reduction cell for the production of a metal, which cell includes: an outer shell and an inner lining of insulating material which form a base, side walls and end walls for containing an electrolytic bath; an anode; a cathode located on the base of the cell; and a plurality of collector bars which electrically connect the cathode to an electrical current carrier that is external to the cell, wherein each collector bar includes an elongated first section that contacts the cathode and at least one end section that extends through one of the side walls and is electrically connected to the electrical current carrier, and wherein the cell is characterised in that, for the purpose of controlling current distribution, the first section of each collector bar includes a core of relatively high electrical conductivity material and an outer housing of a more mechanically and chemically resistant material than the core material and the end section of each collector bar is formed from relatively low thermal conductivity material.  
     
     
         2 . The cell defined in  claim 1  wherein the core material is copper.  
     
     
         3 . The cell defined in  claim 1  or  claim 2  wherein the outer housing material is a relatively low electrical conductivity material compared to the core material.  
     
     
         4 . The cell defined in  claim 3  wherein the outer housing material is steel.  
     
     
         5 . The cell defined in any one of the preceding claims wherein the end section material is steel.  
     
     
         6 . The cell defined in any one of the preceding claims wherein the cathode is in the form of a plurality of blocks that are positioned side by side on the base of the cell.  
     
     
         7 . The cell defined in  claim 6  wherein the cathode blocks extend side by side along the length of the cell with the ends of the blocks contiguous with the side walls of the cell.  
     
     
         8 . The cell defined in  claim 7  wherein there is one collector bar per cathode block, with the first section extending along the length of the block and the end sections of the bar being formed from relatively low thermal conductivity material and extending through opposite side walls.  
     
     
         9 . The cell defined in  claim 7  wherein there are two collector bars per block, with the first section of one bar extending substantially half way along the length of the block with an end section extending through one side wall and the first section of the other bar extending substantially half way along the length of the block with an end section extending through the other side wall.  
     
     
         10 . The cell defined in any one of  claims 6  to  9  wherein the undersurface of the block includes a channel which receives the first section of the collector bar.  
     
     
         11 . The cell defined in  claim 10  wherein the first section of the collector bar is cast or glued in the channel.  
     
     
         12 . The cell defined in any one of the preceding claims includes a means for increasing the effective surface area of electrical contact between the cathode and the relatively high electrical conductivity material core of each collector bar.  
     
     
         13 . The cell defined in any one of the preceding claims includes a means for improving both the longitudinal and transverse distribution of current in the cathode.  
     
     
         14 . The cell defined in  claim 10  wherein the electrical contact means includes a plurality of electrical contact plugs mounted in electrical contact to the cathode and to the collector bars.