Method for separating metal components

Patent metadata

Field	Value
Publication number	US-11066724-B2
Application number	US-201616066737-A
Country	US
Kind code	B2
Filing date	Dec 27, 2016
Priority date	Jan 5, 2016
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

A method for separating metal components from a treatment material containing a silicate and metal elements includes: a reaction step of reacting the treatment material and a molten alkali hydroxide in which bubbles due to water vapor derived from water are generated by heating a hydroxide of an alkali metal or an alkaline-earth metal and the water in a state where the hydroxide and the water coexist, to obtain a reaction product; and a first precipitation step of dissolving the reaction product of the treatment material and the molten alkali hydroxide after the reaction step in water, thereby generating a precipitate containing the metal elements.

First claim

The invention claimed is:

1. A method for separating metal components derived from metal elements, from a treatment material containing a silicate and the metal elements, the method comprising:
a reaction step of reacting the treatment material and a molten alkali hydroxide in which bubbles due to water vapor derived from water are generated by heating a hydroxide of an alkali metal or an alkaline-earth metal and the water in a state where the hydroxide of the alkali metal or the alkaline-earth metal and the water coexist, to obtain a reaction product; and
a first precipitation step of dissolving the reaction product of the treatment material and the molten alkali hydroxide after the reaction step in water to generate a precipitate containing the metal elements in an obtained solution,
wherein the hydroxide of the alkali metal or the alkaline-earth metal and the water are heated at a heating rate of 7° C./min or higher in the reaction step.

2. The method for separating the metal components according to claim 1 , wherein the hydroxide of the alkali metal or the alkaline-earth metal and the water are heated at a heating rate of 15° C./min or higher in the reaction step.

3. The method for separating the metal components according to claim 1 , wherein the hydroxide of the alkali metal or the alkaline-earth metal and the water are heated at a heating rate of 100° C./min or higher in the reaction step.

4. The method for separating the metal components according to claim 1 , wherein
in the first precipitation step,
all or part of the silicate ions in the reaction product of the treatment material and the molten alkali hydroxide are contained in a liquid component of the solution in which the precipitate is generated.

5. The method for separating the metal components according to claim 1 , wherein the treatment material is a silicate ore.

6. The method for separating the metal components according to claim 1 , wherein the treatment material is eudialyte or zircon.

7. The method for separating the metal components according to claim 1 , wherein the hydroxide of the alkali metal or the alkaline-earth metal is NaOH, KOH, or Ca(OH) 2 .

8. The method for separating the metal components according to claim 1 , wherein the metal element contained in the treatment material is a rare earth element.

9. The method for separating the metal components according to claim 1 , wherein the metal element contained in the treatment material is Mn, Zr, or a combination of Mn and Zr.

10. The method for separating the metal components according to claim 1 , wherein the temperature of the molten alkali hydroxide in the reaction step is not lower than 100° C. and not higher than 600° C.

11. The method for separating the metal components according to claim 1 , wherein an amount of the molten alkali hydroxide in the reaction step is not less than 0.1 times and not greater than 10 times with respect to the treatment material on a mass basis.

12. The method for separating the metal components according to claim 1 , further comprising
after the reaction step and before the first precipitation step,
a keeping step of keeping the molten alkali hydroxide in which the generation of the bubbles stops and the treatment material in a state where the molten alkali hydroxide and the treatment material are heated.

13. The method for separating the metal components according to claim 1 , further comprising
after the first precipitation step,
an acid leaching step of leaching out the metal elements contained in the precipitate obtained in the first precipitation step into an acid, thereby separating the metal elements from the precipitate.

14. The method for separating the metal components according to claim 1 , further comprising
after the first precipitation step:
a roasting step of roasting the precipitate obtained in the first precipitation step; and
an acid leaching step of leaching out the metal elements contained in the precipitate after the roasting step into an acid, thereby separating the metal elements from the precipitate.

15. The method for separating the metal components according to claim 13 , wherein a hydrochloric acid solution is used as the acid.

16. The method for separating the metal components according to claim 13 , further comprising
after the acid leaching step,
a first solvent extraction step of separating the metal elements contained in an acid leachate obtained in the acid leaching step from the acid leachate by solvent extraction to obtain a solvent extraction solution containing the metal elements.

17. The method for separating the metal components according to claim 16 , further comprising
after the first solvent extraction step:
a second precipitation step of mixing a precipitant and a loaded/pregnant strip obtained by stripping the metal elements from the solvent extraction solution obtained in the first solvent extraction step into an aqueous solution, to generate a precipitate containing the metal elements; and
a molten salt electrolysis step of dissolving the precipitate obtained in the second precipitation step in a molten salt and then performing molten salt electrolysis, thereby electrowinning the metal components derived from the metal elements contained in the precipitate.

18. The method for separating the metal components according to claim 13 , further comprising
after the acid leaching step,
an ion exchange step of separating the metal elements contained in an acid leachate obtained in the acid leaching step from the acid leachate by an ion exchange method to obtain an eluate containing the metal elements.

19. The method for separating the metal components according to claim 18 , further comprising
after the ion exchange step,
a second solvent extraction step of separating the metal elements contained in the eluate, from the eluate by solvent extraction to obtain a solvent extraction solution containing the metals element.

20. The method for separating the metal components according to claim 19 , further comprising
after the second solvent extraction step:
a third precipitation step of mixing a precipitant and a loaded/pregnant strip obtained by stripping the metal elements from the solvent extraction solution obtained in the second solvent extraction step into an aqueous solution, to generate a precipitate containing the metal elements; and
a molten salt electrolysis step of dissolving the precipitate obtained in the third precipitation step in a molten salt and then performing molten salt electrolysis, thereby electrowinning the metal components derived from the metal elements contained in the solvent extraction solution.

21. The method for separating the metal components according to claim 1 , further comprising
after the first precipitation step,
a silicon dioxide generation step of generating silicon dioxide from a supernatant liquid obtained by separating the precipitate from the solution in the first precipitation step.

22. The method for separating the metal components according to claim 1 , wherein
the treatment material is eudialyte,
NaOH as the hydroxide of the alkali metal and the water are heated at a heating rate of 100° C./min or higher in the reaction step, and
a rare earth metal is separated as the metal components from the treatment material.

Assignees

• Sumitomo Electric Industries
• Aist

Inventors

• Awazu Tomoyuki
• Majima Masatoshi
• Tsubokura Mitsutaka
• Oishi Tetsuo

Classifications

• Y02P10/20

  Recycling · CPC title

• C22B34/10

  Obtaining titanium, zirconium or hafnium · CPC title

• C25C3/30

  of manganese · CPC title

• C22B3/12 Primary

  in inorganic alkaline solutions · CPC title

• C25C3/26

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