Method for manufacturing metal lithium

Patent metadata

Field	Value
Publication number	US-11280012-B2
Application number	US-201616308079-A
Country	US
Kind code	B2
Filing date	Jun 7, 2016
Priority date	Jun 7, 2016
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

The present invention relates to a method for producing metallic lithium, and specifically a method for preparing lithium metal according to an embodiment of the present invention, comprises: preparing lithium phosphate; preparinge a mixture by adding a chlorine compound to the lithium phosphate; heating the mixture; obtaining lithium chloride by reacting the lithium phosphate and the chloride compound in the mixture; producing molten lithium metal by electrolyzing the lithium chloride; and recovering the molten lithium metal is disclosed.

First claim

The invention claimed is:

1. A method for preparing lithium metal, comprising:
preparing lithium phosphate;
preparing a mixture by adding a chloride compound to the lithium phosphate;
heating the mixture;
obtaining lithium chloride by reacting the lithium phosphate and the chloride compound in the mixture;
producing molten lithium metal by electrolyzing the lithium chloride; and
recovering the molten lithium metal in a molten state,
wherein the recovering includes collecting the molten lithium metal by reciprocating a recovery apparatus up and down,
wherein the chloride compound is calcium chloride (CaCl 2 ) or calcium chloride hydrate, and
wherein the step of heating the mixture is carried out in a temperature range of 500° C. to 900° C.

2. hod of claim 1 , further comprising:
supplying the obtained lithium chloride continuously to a electrolytic bath where electrolysis is performed, after the step of obtaining lithium chloride by reacting the lithium phosphate and the chloride compound in the mixture.

3. The method of claim 1 ,
wherein the step of heating the mixture is carried out for 1 hour or more.

4. The method of claim 1 ,
wherein the step of heating the mixture is carried out in an air atmosphere.

5. The method of claim 1 ,
wherein in the step of heating the mixture, the mixture further comprises lithium chloride, potassium chloride, or a mixture thereof.

6. The method of claim 1 ,
wherein in the step of obtaining lithium chloride by reacting the lithium phosphate and the chloride compound in the mixture, chlorapatite (Ca 5 (PO 4 ) 3 Cl) is produced as a by-product of the reaction.

7. The method of claim 6 , further comprising:
precipitating the chlorapatite (Ca 5 (PO 4 ) 3 Cl); and
obtaining the lithium chloride by separating the precipitated chlorapatite (Ca 5 (PO 4 ) 3 Cl), after the step of obtaining lithium chloride by reacting the lithium phosphate and the chloride compound in the mixture.

8. The method of claim 1 ,
wherein the step of preparing lithium phosphate comprising:
removing impurities including magnesium, boron or calcium contained in a brine by adding a hydroxide anion to the brine to precipitate the impurities; and
precipitating lithium phosphate from lithium contained in the brine by putting a phosphorus supplying material into the filtrate solution in which the impurities are removed.

9. The method of claim 1 ,
wherein the step of producing molten lithium metal by electrolyzing the lithium chloride is carried out in a temperature range of 350° C. to 1,300° C.

10. The method of claim 1 ,
wherein in the step of producing molten lithium metal by electrolyzing the lithium chloride, oxygen and/or moisture is controlled to 50 ppm or less (except for 0 ppm).

11. The method of claim 1 ,
wherein in the step of producing molten lithium metal by electrolyzing the lithium chloride, a electrolyte used in the electrolysis is the lithium chloride which is electrolyzed, other lithium chloride, potassium chloride, or a mixture thereof.

12. The method of claim 1 ,
wherein the step of recovering the molten lithium metal is performed by a difference of specific gravity.

Assignees

• Res Inst Ind Science & Tech

Inventors

• Park Woon Kyoung
• Park Dae Yeob
• Park Kwang Seok
• Jung Woo Chul

Classifications

• C25C3/02 Primary

  of alkali or alkaline earth metals · CPC title

• C25C3/00 Primary

  Electrolytic production, recovery or refining of metals by electrolysis of melts (C25C5/00 takes precedence) · CPC title

• C25C5/04

  from melts · CPC title

• C25C7/08

  Separating of deposited metals from the cathode · CPC title