Electrode for Membrane Electrolysis Cells

Abstract

The invention relates to an electrode for membrane electrolysis cells comprising a grooved metal support favouring the gas release and the electrolyte renewal on its surface. The grooved geometry of the support may be obtained by erosion of a metal sheet with abrasive media in a continuous process.

1 . Electrolysis cell comprising an ion-exchange membrane and at least one electrode in direct contact with said ion-exchange membrane, the electrode comprising a metal substrate having at least one surface equipped with a multiplicity of grooves, the depth of the grooves ranging from 0.001 to 0.1 mm and the distance between adjacent grooves ranging from 0.1 to 0.5 mm. 
   
   
       2 . The electrolysis cell according to  claim 1 , the depth of the grooves ranging from 0.005 to 0.02 mm. 
   
   
       3 . The electrolysis cell according to  claim 1 , the grooves being generally parallel along the whole surface. 
   
   
       4 . The electrolysis cell according to  claim 1 , the locally parallel grooves intersecting one another. 
   
   
       5 . The electrolysis cell according to  claim 1 , the material of the electrode substrate comprising one or more of titanium and alloys thereof, nickel and alloys thereof, or stainless steel. 
   
   
       6 . The electrolysis cell according to  claim 5 , the electrode substrate having a geometry comprising one or more of punched or expanded sheets, meshes and louvered structures. 
   
   
       7 . The electrolysis cell according to  claim 1 , further comprising a catalytic coating applied to the surface provided with grooves. 
   
   
       8 . The electrolysis cell according to  claim 7 , the catalytic coating comprising noble metals or oxides thereof. 
   
   
       9 . The electrolysis cell of  claim 1 , the at least one electrode assembled with the grooves generally parallel along the whole surface oriented in a mostly vertical direction. 
   
   
       10 . Method for manufacturing an electrolysis cell according to  claim 1  comprising the step of forming a multiplicity of grooves on the metal substrate of the electrode by continuous erosion. 
   
   
       11 . The method according to  claim 10 , the erosion carried out continuously by means of at least one device comprising one or more of rollers of abrasive paper or fabric, grindstones or lamellar grinding wheels. 
   
   
       12 . The method according to  claim 10 , the erosion carried out by means of a draw-bench or a rolling mill. 
   
   
       13 . Process of electrolysis of an alkali chloride brine carried out by applying direct electric current in a membrane electrolysis cell comprising an ion-exchange membrane and at least one electrode in direct contact with said ion-exchange membrane, the electrode comprising a metal substrate having at least one surface equipped with a multiplicity of grooves, the depth of the grooves ranging from 0.001 to 0.1 mm and the distance between adjacent grooves ranging from 0.1 to 0.5 mm, the process comprising evolving a gaseous product on the surface of the at least one electrode. 
   
   
       14 . The process according to  claim 13 , the gaseous product comprising anodically-evolved chlorine or cathodically-evolved hydrogen. 
   
   
       15 . The process according to  claim 13 , the density of the direct electric current being at least 5 kA/m 2 . 
   
   
       16 . The process according to  claim 13 , the pressure differential across the membrane of the electrolysis cell being at least 3000 Pa. 
   
   
       17 . The process according to  claim 13 , the concentration of the brine at the anodic compartment outlet being at most 200 g/l. 
   
   
       18 . The process according to  claim 13 , the caustic solution at a weight concentration of at least 33% is produced at the cathodic compartment.