Electrochemical Method and Apparatus For Removing Oxygen From a Compound or Metal

Abstract

A cathode comprising an oxygen-containing compound, or a metal containing dissolved oxygen, is arranged in contact with a melt comprising a hydroxide of an alkali metal. An inert anode, advantageously comprising nickel, is also arranged in contact with the melt and a potential is applied between the anode and the cathode such that oxygen is removed from the compound or the metal.

1 . A method of removing oxygen from a compound, metal or alloy, comprising the steps of:
 arranging a cathode comprising the compound, metal or alloy in contact with a melt comprising a hydroxide of an alkali metal;   arranging an inert anode in contact with the melt, wherein the anode comprises nickel; and   applying a potential between the anode and the cathode sufficient to remove oxygen from the compound, metal or alloy.   
   
   
       2 - 30 . (canceled) 
   
   
       31 . The method according to  claim 1 , in which the anode comprises nickel, a nickel alloy, an intermetallic compound containing nickel, or a nickel compound, such as a nickel oxide. 
   
   
       32 . The method according to  claim 1 , in which the anode comprises a sufficient proportion of nickel to render the anode substantially inert in the melt. 
   
   
       33 . The method according to  claim 1 , in which the anode is substantially inert with respect to the melt under operating conditions. 
   
   
       34 . The method according to  claim 1 , in which the potential at the cathode is lower than a potential for continuous evolution of hydrogen from the melt;
 and/or in which the potential at the cathode is lower than a potential for continuous deposition of the alkali metal.   
   
   
       35 . The method according to  claim 1 , in which the melt further comprises an oxide of an alkali metal, the oxide preferably being dissolved in the hydroxide;
 and in which the potential between the anode and the cathode is preferably lower than a potential for continuous decomposition of the alkali metal oxide or for continuous removal of the alkali metal oxide from the melt.   
   
   
       36 . The method according to  claim 1 , in which the alkali metal is sodium or potassium;
 and/or in which the metal is iron, cobalt, nickel, copper, zinc, or lead.   
   
   
       37 . The method according to  claim 1 , which has as its product the metal. 
   
   
       38 . The method according to  claim 1 , in which the compound or metal from which oxygen is removed is a solid compound or a solid metal;
 and/or in which the compound from which oxygen is removed comprises a metal and oxygen.   
   
   
       39 . The method according to  claim 1 , in which the compound, metal or alloy forms part of a precursor material at the cathode, the precursor material comprising more than one metal or metal compound;
 the method preferably having as its product an alloy or an intermetallic compound of the metals present in the precursor material.   
   
   
       40 . The method according to  claim 1 , in which the melt is at a temperature of below 650° C. during operation. 
   
   
       41 . The method according to  claim 1 , in which the melt is at a temperature of above 500° C. during operation. 
   
   
       42 . The method according to  claim 1 , comprising the further step of arranging a reference electrode in contact with the melt for controlling the potential of the cathode and/or the anode and/or the potential or voltage applied between the anode and the cathode. 
   
   
       43 . The method according to  claim 1 , in which the potential between the anode and the cathode is lower than a potential for continuous decomposition of the alkali metal hydroxide. 
   
   
       44 . The method according to  claim 1 , in which there is substantially no electronic conductivity in the melt during operation. 
   
   
       45 . The method according to  claim 1 , in which, during operation, substantially no alkali metal dissolves in the melt as a metallic species. 
   
   
       46 . A method of removing oxygen from a compound, metal or alloy, comprising the steps of:
 arranging a cathode comprising the compound, metal or alloy in contact with a melt comprising a hydroxide of an alkali metal;   arranging an inert anode in contact with the melt; and   applying a potential between the anode and the cathode sufficient to remove oxygen from the compound, metal or alloy.   
   
   
       47 . The method according to  claim 46 , in which the inert anode comprises nickel. 
   
   
       48 . The method according to  claim 46 , in which the compound, metal or alloy comprises one or more metals iron, cobalt, nickel, copper, zinc or lead. 
   
   
       49 . The method according to  claim 46 , in which the melt comprises sodium hydroxide and sodium oxide, or comprises potassium hydroxide and potassium oxide. 
   
   
       50 . An apparatus for electro-decomposition, comprising:
 a receptacle for a melt comprising a hydroxide of an alkali metal;   an inert anode; and   a power supply for applying an electro-decomposition voltage between the inert anode and a cathode comprising a solid compound for electro-decomposition.   
   
   
       51 . The apparatus according to  claim 50 , in which the anode comprises nickel. 
   
   
       52 . An anode for an apparatus for electro-decomposition, wherein said apparatus comprises:
 a receptacle for a melt comprising a hydroxide of an alkali metal;   an inert anode; and   a power supply for applying an electro-decomposition voltage between the inert anode and a cathode comprising a solid compound for electro-decomposition.   
   
   
       53 . An anode for use in a method for removing oxygen from a compound, metal or alloy, wherein said method comprises the steps of:
 arranging a cathode comprising the compound, metal or alloy in contact with a melt comprising a hydroxide of an alkali metal;   arranging an inert anode in contact with the melt, wherein the anode comprises nickel; and   applying a potential between the anode and the cathode sufficient to remove oxygen from the compound, metal or alloy.   
   
   
       54 . An intermetallic compound, metal or alloy fabricated using a method for removing oxygen from a compound, metal or alloy, wherein said method comprises the steps of:
 arranging a cathode comprising the compound, metal or alloy in contact with a melt comprising a hydroxide of an alkali metal;   arranging an inert anode in contact with the melt, wherein the anode comprises nickel; and   applying a potential between the anode and the cathode sufficient to remove oxygen from the compound, metal or alloy.