Bipolar electrodes with high energy efficiency, and use thereof for synthesising sodium chlorate

Abstract

The invention relates to novel bipolar electrodes with a cathodic coating on one portion of the electrode and an anodic coating on another portion of the same electrode. The anodic coating is preferably a DSA coating and the cathodic coating is an alloy such as Fe 3−x Al- 1+x M y T z . The invention also relates to the use of said novel electrodes for synthesising sodium chlorate.

1 . A bipolar electrode with high energy efficiency, which electrode has a part provided with a cathodic coating and a second part that is distinct from the first one and is provided with an anodic coating. 
     
     
         2 . A bipolar electrode according to  claim 1 , wherein the anodic coating is of the DSA type. 
     
     
         3 . A bipolar electrode according to  claim 1 , wherein the anodic coating is an alloy with the formula:
   Fe 3−x Al 1+x M y T z      in which:   M represents one or several catalytic species selected from Ru, Ir, Pd, Pt, Rh, Os, Re, Ag and Ni;   T represents one or several elements from Mo, Co, Cr, V, Cu, Zn, Nb, W, Zr, Y;   Mn, Cb, Si, B, C, O, N, P, F, S, Cl   x is a number greater than −1 and lower than or equal to +1;   y is a number greater than 0 and lower than or equal to +1; and   z is a number between 0 and +1.   
     
     
         4 . A bipolar electrode according to  claim 1 , wherein the coatings are applied on a substrate of steel or of titanium. 
     
     
         5 . A bipolar module of electrodes, comprising an electrode unit containing a plurality of electrodes in accordance with  claim 1 . 
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . The method of synthesizing sodium chlorate which comprises electrolysis with the bipolar electrode according to  claim 1 . 
     
     
         9 . The method of synthesizing sodium chlorate which comprises electrolysis with the bipolar module of  claim 5 . 
     
     
         10 . A bipolar electrode according to  claim 3 , wherein the coatings are applied on a substrate of steel or of titanium. 
     
     
         11 . A bipolar module of electrodes, comprising an electrode unit containing a plurality of electrodes in accordance with  claim 3 . 
     
     
         12 . A bipolar module of electrodes, comprising an electrode unit containing a plurality of electrodes in accordance with  claim 4 . 
     
     
         13 . A bipolar module of electrodes, comprising an electrode unit containing a plurality of electrodes in accordance with  claim 10 .