Electrochemical cell for metal production

Abstract

A process for reducing to metallic form metal oxides includes cathodically electrolysing the oxide in the presence of a molten salt electrolyte whilst controlling the potential of the cathode so as to favour oxygen ionisation over deposition of metal from the cations present in the molten salt, and an apparatus for performing the said process. The apparatus is free from bolted or screwed fittings and includes an electrochemical cell that includes a body or housing, a cathode container, and a cathode connector, wherein the body or housing is maintained as the cathode.

1 . An apparatus for performing a process for reducing to metallic form metal oxides, the metal oxides comprising metal oxides present in spent nuclear fuel, wherein the apparatus comprises: 
 an electrochemical cell which comprises: 
 a body or housing;  
 a cathode container; and  
 a cathode connector;  
   wherein said body or housing is maintained as the cathode, and said electrochemical cell is free from bolted or screwed fittings.    
     
     
         2 . An apparatus as claimed in  claim 1  wherein said cathode connector is affixed to an internal surface of the cell.  
     
     
         3 . An apparatus as claimed in  claim 2  wherein said cathode connector is affixed to an internal surface of the cell by means of welding.  
     
     
         4 . An apparatus as claimed in  claim 1  wherein an electrical connection from the cathode container to the body or housing of the cell is provided by means of a cathode connector.  
     
     
         5 . An apparatus as claimed in  claim 4  wherein said electrical connection is provided by means of a press connection.  
     
     
         6 . An apparatus as claimed in  claim 1  wherein said cathode connector comprises a cathode rail.  
     
     
         7 . An apparatus as claimed in  claim 6  wherein said rail is welded to the base of the cell.  
     
     
         8 . An apparatus as claimed in  claim 1  wherein the cathode container comprises a mesh basket or metal oxide retaining vessel.  
     
     
         9 . An apparatus as claimed in  claim 1  wherein the cathode container comprises an assembly of cathode containers.  
     
     
         10 . An apparatus as claimed in  claim 9  wherein said assembly comprises an assembly of mesh baskets or metal oxide retaining vessels.  
     
     
         11 . An apparatus as claimed in  claim 1  wherein the electromechanical cell further comprises a carbon anode.  
     
     
         12 . An apparatus as claimed in  claim 1  wherein the body or housing of the cell is maintained as the cathode by the provision of an electrical connection from a power supply to the body or housing of the cell.  
     
     
         13 . A process for reducing to metallic form metal oxides, said metal oxides comprising metal oxides present in spent nuclear fuel, the process comprising: 
 cathodically electrolysing the oxide in the presence of a molten salt electrolyte in an apparatus, the apparatus comprising: 
 an electrochemical cell which comprises: 
 a body or housing;  
 a cathode container; and  
 a cathode connector;  
 wherein said body or housing is maintained as the cathode, and said electrochemical cell is free from bolted or screwed fittings;  
 
 controlling the potential of the cathode so as to favour oxygen ionisation over deposition of metal from the cations present in the molten salt.  
   
     
     
         14 . A process as claimed in  claim 13  wherein 
 maintaining the body or housing of the cell as the cathode while bringing the body or housing of the cell into contact with the cathode container by means of a press connection between said container and a cathode connector.    
     
     
         15 . A process as claimed in  claim 13  wherein the oxide comprises the oxide of zirconium or hafnium.  
     
     
         16 . A process as claimed in  claim 13  wherein the oxide comprises an actinide oxide.  
     
     
         17 . A process as claimed in  claim 16  wherein the actinide oxide comprises uranium oxide, irradiated uranium oxide and/or mixed uranium/plutonium oxide fuel pellets.  
     
     
         18 . A process as claimed in  claim 17  wherein the uranium oxide comprises uranium dioxide.  
     
     
         19 . A process as claimed in  claim 13  wherein the oxide is located in a mesh basket which forms the cathode.  
     
     
         20 . A process as claimed in  claim 13  wherein the molten salt electrolyte comprises at least one chloride salt.  
     
     
         21 . A process as claimed in  claim 20  wherein chloride salt is CaCl 2  or BaCl 2 .  
     
     
         22 . A process as claimed in  claim 13  wherein the spent nuclear fuel comprises cladding.  
     
     
         23 . A process as claimed in  claim 13 , further comprising: 
 removing the cladding from the fuel prior to cathodically electrolysing the oxide and controlling the potential of the cathode.    
     
     
         24 . A process as claimed in  claim 13  further comprising: 
 using the metal oxides reduced to metallic form as the feed for an electrorefining process.    
     
     
         25 . A process as claimed in claims  24  wherein the electrorefining process is carried out in a same electrolytic cell as cathodically electrolysing the oxide and controlling the potential of the cathode.  
     
     
         26 . (canceled)