Trimanganese tetraoxide and its production process

Patent metadata

Field	Value
Publication number	US-9487883-B2
Application number	US-201314395191-A
Country	US
Kind code	B2
Filing date	Apr 17, 2013
Priority date	Apr 20, 2012
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

Trimanganese tetraoxide has high reactivity with a lithium compound, is excellent in handling efficiency, and is suitable as a manganese material of a lithium manganese oxide, and its production process. Trimanganese tetraoxide particles including trimanganese tetraoxide primary particles having an average primary particle size of at most 2 μm agglomerated, the pore volume of pores being at least 0.4 mL/g. The most frequent pores are preferably pores having a diameter of at most 5 μm. The trimanganese tetraoxide particles can be obtained by producing trimanganese tetraoxide particles, which includes directly crystallizing trimanganese tetraoxide from a manganese salt aqueous solution, wherein the manganese salt aqueous solution and an alkali aqueous solution are mixed so that the oxidation-reduction potential is at least 0 mV and OH − /Mn 2+ (mol/mol) is at most 0.55, to obtain a slurry, and the solid content concentration of the slurry is adjusted to be at most 2 wt %.

First claim

The invention claimed is:

1. Trimanganese tetraoxide particles comprising trimanganese tetraoxide primary particles which have an average primary particle size of at most 2 μm and which are agglomerated, the pore volume of pores being at least 0.5 mL/g,
wherein the pore volume ratio of pores having a diameter of at least 10 μm as measured by a mercury intrusion technique is at most 20%.

2. The trimanganese tetraoxide particles according to claim 1 , wherein the most frequent pores are pores having a diameter of at most 5 μm.

3. The trimanganese tetraoxide particles according to claim 1 , wherein the average particle size is at least 5 μm and at most 50 μm.

4. The trimanganese tetraoxide particles according to claim 1 , wherein the modal particle size is larger than the average particle size.

5. The trimanganese tetraoxide particles according to claim 1 , wherein the content of sulfate radicals is at most 0.5 wt %.

6. The trimanganese tetraoxide particles according to claim 1 , wherein the average primary particle size is at least 0.2 μm and at most 0.5 μm.

7. The trimanganese tetraoxide particles according to claim 1 , wherein the pore volume of pores is at most 2 mL/g.

8. A process for producing the trimanganese tetraoxide particles as defined in claim 1 , which comprises a crystallization step of directly crystallizing trimanganese tetraoxide from a manganese salt aqueous solution, wherein in the crystallization step, the manganese salt aqueous solution and an alkali aqueous solution are mixed so that the oxidation-reduction potential is at least 0 mV and OH − /Mn 2+ (mol/mol) is at most 0.55, to obtain a slurry, and the solid content concentration of the slurry is adjusted to be at most 2 wt %.

9. The production process according to claim 8 , wherein the oxidation-reduction potential is at least 60 mV and at most 200 mV.

10. The production process according to claim 8 , wherein in the crystallization step, the slurry having a solid content concentration of at most 2 wt % is aged for at least 10 minutes.

11. The production process according to claim 8 , wherein the temperature of the manganese salt aqueous solution is at least 60° C. and at most 95° C.

12. The production process according to claim 8 , wherein OH − /Mn 2+ (mol/mol) is at least 0.35.

13. A process for producing a lithium oxide, which comprises a mixing step of mixing the trimanganese tetraoxide particles as defined in claim 1 with a lithium compound, and a heating step of subjecting the mixture to heat treatment.

Assignees

• Tosoh Corp

Inventors

• Iwata Eiichi
• Yamashita Miki
• Doi Masaharu

Classifications

• C01P2006/12

  Surface area · CPC title

• C30B7/12 Primary

  by electrolysis · CPC title

• Y10T428/2982

  Particulate matter [e.g., sphere, flake, etc.] · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• C01P2006/16

  Pore diameter · CPC title