Method for manufacturing zirconium metal and hafnium metal

Patent metadata

Field	Value
Publication number	US-9315915-B2
Application number	US-200913001870-A
Country	US
Kind code	B2
Filing date	Jun 29, 2009
Priority date	Jun 30, 2008
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

An object of the present invention is to provide a method of producing metal zirconium, the method having a fewer steps and a smaller amount of secondary wastes generated, wherein the metal zirconium is obtained from a zirconium compound containing hafnium. A method of producing metal zirconium according to the present invention includes: a separation step of separating a hafnium oxychloride from a first substance containing a zirconium oxychloride and a hafnium oxychloride to obtain a second substance having a higher content of the zirconium oxychloride; a calcination step of calcining the second substance to obtain a third substance containing at least any of a zirconium oxychloride and a zirconium oxide; and a direct reduction step of holding the third substance in a molten salt with the third substance brought into contact with a cathode and applying a voltage between the cathode and an anode to directly reduce the third substance to obtain metal zirconium.

First claim

The invention claimed is:

1. A method of producing zirconium metal and hafnium metal, comprising:
a separation step of separating a hafnium oxychloride from a first substance containing a zirconium oxychloride and a hafnium oxychloride to obtain a second substance having a higher content of the zirconium oxychloride;
a calcination step of calcining the second substance in an inert gas atmosphere to remove a moisture content and to obtain a third substance containing at least one of a zirconium oxychloride or a zirconium oxide;
a direct reduction step of holding the third substance in a molten salt with the third substance brought into contact with a cathode and applying a voltage between the cathode and an anode to directly reduce the third substance as it is to obtain zirconium metal;
a calcination step of calcining a sixth substance under an inert gas atmosphere, the sixth substance being separated from the first substance in the separation step and having a higher content of the hafnium oxychloride to obtain a seventh substance containing at least one of a hafnium oxychloride or a hafnium oxide; and
a direct reduction step of holding the seventh substance in a molten salt with the seventh substance brought into contact with a cathode and applying a voltage between the cathode and an anode to directly reduce the seventh substance as it is to obtain hafnium metal;
wherein said method does not comprise carbothermal reduction of ZrO 2 to ZrCl 4 .

2. The method of producing zirconium metal and hafnium metal according to claim 1 , wherein in the direct reduction step, the third substance is held in a solid state in a basket connected to the cathode and is directly reduced as in a solid state.

3. The method of producing zirconium metal and hafnium metal according to claim 1 , wherein the molten salt contains a chloride of any of an alkali metal and an alkaline earth metal and an oxide of the same metal element as the metal element constituting the chloride.

4. The method of producing zirconium metal and hafnium metal according to claim 3 , wherein the molten salt is a molten salt obtained by melting, in a molten salt of any chloride of LiCl, MgCl 2 and CaCl 2 , an oxide of the same metal element as the metal element constituting the chloride.

5. The method of producing zirconium metal and hafnium metal according to claim 4 , further comprising a molten salt regeneration step of electrolyzing a chloride of at least any of Li, Mg and Ca present in the molten salt used in the direct reduction step to regenerate at least one of Li metal, Mg metal or Ca metal.

6. The method of producing zirconium metal and hafnium metal according to claim 1 , wherein in the direct reduction step, the seventh substance is held in a solid state in a basket connected to the cathode and is directly reduced as in a solid state.

7. The method of producing zirconium metal and hafnium metal according to claim 1 , wherein the molten salt contains a chloride of at least one of an alkali metal, an alkaline earth metal, or an oxide of the same metal element as the metal element constituting the chloride.

8. The method of producing zirconium metal and hafnium metal according to claim 7 , wherein the molten salt comprises at least one of LiCl, MgCl 2 or CaCl 2 , or at least one of Li 2 O, MgO or CaO.

9. A method of producing zirconium metal and hafnium metal comprising:
(A) a separation step of separating a hafnium oxychloride from a first substance containing a zirconium oxychloride and a hafnium oxychloride and recovering a second substance having a higher content of the zirconium oxychloride and lower content of hafnium oxychloride than said first substance;
a calcination step of calcining the second substance in an inert gas atmosphere to remove a moisture content and to obtain a third substance containing at least one of a zirconium oxychloride and a zirconium oxide;
a direct reduction step of holding the third substance in a molten salt with the third substance brought into contact with a cathode and applying a voltage between the cathode and an anode to directly reduce the third substance as it is to obtain zirconium metal; and
(B) a separation step of separating a zirconium oxychloride from a first substance containing a zirconium oxychloride and a hafnium oxychloride to obtain and recovering a sixth substance having a higher content of the hafnium oxychloride and lower content of zirconium oxychloride than said first substance;
a hydroxide precipitation step of adding a hydroxide to a sixth substance to obtain an eighth substance containing a hafnium hydroxide;
a calcination step of calcining the eighth substance in an inert as atmosphere to obtain a ninth substance containing a hafnium oxide; and
a direct reduction step of holding the ninth substance in a molten salt with the ninth substance brought into contact with a cathode and applying a voltage between the cathode and an anode to directly reduce the ninth substance as it is to obtain metal hafnium;
wherein said method does not comprise carbothermal reduction of ZrO 2 to ZrCl 4 .

10. The method of claim 9 , further comprising extracting ZrSiO 4 -containing ore that also contains hafnium to generate zirconium and hafnium oxychlorides prior to the separation step.

11. The method of claim 1 , further comprising extracting ZrSiO 4 -containing ore that also contains hafnium to generate zirconium and hafnium oxychlorides prior to the separation step.

12. The method of claim 1 , wherein an amount of chloride-containing secondary wastes is reduced compared to an otherwise similar method that employs chlorination-volatilization or that employs the Kroll process to produce zirconium metal and hafnium metal.

Assignees

• Fujita Reiko
• Mizuguchi Koji
• Nakamura Hitoshi
• Fuse Kouki
• Kawamoto Mitsuru
• Ito Masaru
• Toshiba Kk

Inventors

• Fujita Reiko
• Mizuguchi Koji
• Nakamura Hitoshi
• Fuse Kouki
• Kawamoto Mitsuru
• Ito Masaru

Classifications

• C22B34/14

  Obtaining zirconium or hafnium {(treatment or purification of solutions by liquid-liquid extraction, by ion exchange or by adsorption C22B3/00, C01G25/003, C01G27/003)} · CPC title

• Y02P10/23

  Cross-Sectional Technologies · mapped topic

• C25C3/26 Primary

  of titanium, zirconium, hafnium, tantalum or vanadium · CPC title

• C22B34/1222

  using a halogen containing agent · CPC title

• C22B34/129

  obtaining metallic titanium from titanium compounds by dissociation, e.g. thermic dissociation of titanium tetraiodide, or by electrolysis or with the use of an electric arc · CPC title