WO2006009700B1

WO2006009700B1 - Low temperature refining and formation of refractory metals

Info

Publication number: WO2006009700B1
Application number: PCT/US2005/020994
Authority: WO
Inventors: William E O'grady; Graham T Cheek
Original assignee: US Naval Research Laboratory NRL; Government of the United States of America
Current assignee: US Naval Research Laboratory NRL; Government of the United States of America
Priority date: 2004-06-16
Filing date: 2005-06-15
Publication date: 2006-11-23
Anticipated expiration: 2006-12-16
Also published as: WO2006009700A3; WO2006009700A2

Abstract

A low temperature method for reducing and purifying refractory metals, metal compounds, and semi-metals using a catalyst. Using this invention, TiO2 can be reduced directly to Ti metal at room temperature. The catalyst is an ion in an electrolyte that catalyzes the rate of the reduction of a compound MX to M, wherein M is a metal or a semi-metal; MX is a metal compound, a semi-metal compound, or a metal or semi-metal dissolved as an impurity in M; and X is an element chemically combined with or dissolved in M.

Claims

AMENDED CLAIMS received by the International Bureau on 08 August 2006 (08.08.2006)ClaimsWhat is claimed:

1. A low temperature electrochemical method for removing specie X from compound MX, comprising the steps of:

A. forming an electrolysis system comprising a MX cathode, an anode, and an electrolyte that includes at least one catalyst, wherein said electrolyte is a non-aqueous ionic-liquid electrolyte and wherein said catalyst is selected from the group of materials which are reduced at less negative reducing potentials than M in MX;

B. passing a current through said system at a voltage determined to remove X from MX; and

C. isolating the reaction product resulting from removal of X from MX.

2. (canceled)

3. The method according to claim ) , where M is selected from the group consisting of metals, metal compounds, semi-metal compounds, and any combination thereof.

4. The method according to claim 1 , where M is selected from the group consisting of Ti, Si, Ge, Zr, Hf, Sm, U, Al, Mg, Nd₁ Mo, Cr, Li, La, Ce, Y, Sc, Be, V, Nb, any alloy thereof, and any combination thereof.

5. The method of claim 1, wherein X is selected from the group consisting of O, C, N, S, and halides.

6. The method according to claim 1, wherein X is O.

7. A low temperature electrochemical method for removing O from TiO₂, comprising the steps of:

A. forming an electrolysis system comprising a TiO₂ cathode, an anode, and an electrolyte ⁽hat includes at least one catalyst, wherein said electrolyte is a non-aqueous ionic-liqujd electrolyte aad wherein said catalyst is selected from the group of materials which arc reduced at less negative reducing potentials than Ti;

B. passing a current through said system at a voltage selected to remove O from said TiO₂; and

C. isolating the reaction product resulting from the removal of O from TiO₂.

8. The method according to claim 1 or 7, wherein said electrolyte is a non-aqueous chloroaluminate system based on nitrogen heterocyclic cations or the functional equivalent thereof.

9. The method according to claim 1 or 7, wherein said electrolyte is a non-aqueous solvent selected from the group consisting of mono and dialkylimidazolium salts.

10. The method according to claim 1 or 7, wherein said electrolyte is a non-aqueous solvent mixture of 1 -ethyI-3-methylimidazolium chloride and aluminum chloride.

11. The method according to claim 1 oτ 7, wherein said electrolyte is 1-ethyl-3- methylimidazolium tetrafluoroborate.

12. The method according to claim 1 or 7, wherein said electrolyte is selected from the group consisting of nitriles, ethers, sulfones, sulfoxides, and amides together with a salt selected from die group consisting of tetraalkylammonium salts, triflouromethanesulfonate salts and tetraflouroborate salts.

13. (canceled)

14. The method according to claim 1 or 7, wherein said catalyst is a metal ton selected from the group of metals which are reduced at less negative reducing potentials than M in MX in claim 1 or Ti in claim 7.

15. The method according to claim 1 or 7, wherein said catalyst is a metal ion added to the electrolyte as a compound containing the desired metal ion or a metal or alloy that produces the desired metal ion in the electrolyte with said metal ion being selected from the group of metals which are reduced at less negative reducing potentials than M in MX in claim 1 or Ti in claim 7.

16. The method according to claim 1 or 7, wherein said catalyst is a metal ion added to the electrolyte by adding a soluble salt containing the metal ion, wherein said metal ion is selected from the group of metals which are reduced at less negative reducing potentials than M in MX in claim 1 or Ti in claim 7.

17. The method according to claim 7, wherein said catalyst is Ag.

18. The method according to claim 1 or 7, wherein said electrolysis occurs in a fluidized bed reactor or a packed bed reactor.

19. A method of adding at least one catalyst to an electrolyte system, comprising depositing the catalyst onto the surface of a material being reduced regardless of the temperature or nature of the electrolyte, wherein said catalyst acts to reduce the supporting material.

20. The method of claim 19, wherein the electrolyte is selected from the group consisting of molten salts, ionic liquids, aqueous solutions, and any combination thereof.