Method, apparatus and means for production of metals in a molten salt electrolyte

Abstract

This invention describes a method of producing a metal, M 1 , in an electrolytic cell consisting of a molten electrolyte, M Z Y-M Z O, at least one anode and at least one cathode, characterised in that the passage of current between said anode(s) and cathode(s) through said electrolyte, produces a metal, M 1 , from a raw material, M 1 X, containing a non-metallic species, X, under conditions such that the potential at the cathode causes the reduction of the M Z cation and the formation of M Z at activities less than one, and the potential at the cathode is insufficient to cause formation of M Z metal as a discrete solid or liquid phase, and the M Z so produced reduces the raw material, M 1 X, at the cathode, to M 1 .

1 . A method of producing a metal, M 1 , in an electrolytic cell consisting of a molten electrolyte, M Z Y-M Z O, at least one anode and at least one cathode, characterised in that the passage of current between said anode(s) and cathode(s) through said electrolyte, produces a metal, M 1 , from a raw material, M 1 X, containing a non-metallic species, X, under conditions such that
 a. the potential at the cathode causes the reduction of the Mz cation and the formation of Mz at activities less than one   b. the potential at the cathode is insufficient to cause formation of Mz metal as a discrete solid or liquid phase   c. and the M Z  so produced reduces the raw material, M 1 X, at the cathode, to M Z .   
   
   
       2 . A method of producing an alloy, M 1 -M 2 - . . . -M n , in an electrolytic cell consisting of a molten electrolyte, M Z Y-M Z O, at least one anode and at least one cathode, characterised in that the passage of current between said anode(s) and cathode(s) through said electrolyte, produces the alloy, M 1 -M 2 - . . . -M Z , from a mixture of raw materials, M 1 X-M 2 X- . . . -M n X, containing non-metallic species, X, under conditions such that
 a. the potential at the cathode causes the reduction of the M Z  cation and the formation of M Z  at activities less than one   b. the potential at the cathode is insufficient to cause formation of M Z  metal as a discrete solid or liquid phase   c. and the M Z  so produced reduces the raw material at the cathode to an alloy M 1 -M 2 - . . . -M n .   
   
   
       3 . A method of producing a composite, M 1 -M 2 A, in an electrolytic cell consisting of a molten electrolyte, M Z Y-M Z O, at least one anode and at least one cathode, characterised in that the passage of current between said anode(s) and cathode(s) through said electrolyte, produces a composite, M 1 -M 2 A, from a raw material, M 1 X-M 2 A, containing non-metallic species, X, and substance, A, under conditions such that
 a. the potential at the cathode causes the reduction of the M Z  cation and the formation of M Z  at activities less than one   b. the potential at the cathode is insufficient to cause formation of M Z  metal as a discrete solid or liquid phase   c. and the M Z  so produced reduces the raw material at the cathode to form a composite, M 1 -M 2 A.   
   
   
       4 . A method in accordance with  claim 1 ,  2 , or  3 , characterised in that the formation of Mz more preferably occurs at an activity between 10 −6  and 5×10 −1 . 
   
   
       5 . A method in accordance with  claim 1 ,  2 , or  3 , characterised in that the formation of M Z  and the reduction of M 1 X occur at the same physical location. 
   
   
       6 . A method in accordance with  claim 1 ,  2 , or  3 , characterised in that the said electrolyte (fused salt) more preferably comprises Ca or Na, or a mixture thereof as the cation(s), M Z . 
   
   
       7 . A method in accordance with  claim 1 ,  2 , or  3 , characterised in that the said electrolyte (fused salt) may also comprise at least one of the following cations: Ba, Li, Sc, Sr or K 
   
   
       8 . A method in accordance with  claim 1 ,  2 , or  3 , characterised in that the said electrolyte (fused salt) more preferably comprises Cl as the anion, Y. 
   
   
       9 . A method in accordance with  claim 1 ,  2 , or  3 , characterised in that the said electrolyte (fused salt) may also comprise F as the anion, Y. 
   
   
       10 . A method in  claim 1 ,  2 , or  3 , where the electrolyte more preferably contains 0.1 to 3 wt % CaO. 
   
   
       11 . A method according to  claim 1 ,  2 , or  3 , in which the raw material contains M 1  and X as constituents of a single phase compound comprised of greater than two elements. 
   
   
       12 . A method according to  claim 1 ,  2 , or  3 , in which the non-metal species, X, comprises at least one of the elements O, S, C or N. 
   
   
       13 . A method according to  claim 1 ,  2 , or  3 , in which the non-metal species, X, more preferably comprises the element O. 
   
   
       14 . A method according to  claim 3 , in which the substance, A, consists of at least one of the following: B, C, O, N, or Si. 
   
   
       15 . A method in accordance with  claim 1 ,  2 , or  3 , characterised in that the metal species, M 1 , M 2  . . . M n , being produced comprises at least one of the following components: Ti, Si, Ge, Zr, Hf, Sm, U, Al, Mg, Nd, Mo, Cr, Nb, V, Ta, Mb, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Be, Sr, Ga, In, Tl, lanthanides or actinides. 
   
   
       16 . An apparatus consisting of an electrolytic cell including an anode, a cathode comprised of a current collector and raw material, and a molten electrolyte, which operates under conditions such that a metal, alloy or composite is formed from said raw material whereby the potential at cathode is sufficient to reduce the M Z  cation and causes the formation of M Z  at activities less than one, and the potential at the cathode is insufficient to cause formation of M Z  metal in either the solid or liquid phase, and the M Z  so produced reduces the raw material, at the cathode, to said metal, alloy or composite. 
   
   
       17 . The anode defined in  claim 15  further comprising either
 a. a carbonaceous material such that CO and CO 2  gas are evolved during electrolysis, or   b. a material such that the anodic electrolysis product is oxygen gas.