Powder, method of producing powder and adsorption apparatus

Patent metadata

Field	Value
Publication number	US-11278864-B2
Application number	US-201916549199-A
Country	US
Kind code	B2
Filing date	Aug 23, 2019
Priority date	Sep 28, 2009
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

The present invention provides that powder is mainly constituted from secondary particles of hydroxyapatite. The secondary particles are obtained by drying a slurry containing primary particles of hydroxyapatite and aggregates thereof and granulating the primary particles and the aggregates. A bulk density of the powder is 0.65 g/mL or more and a specific surface area of the secondary particles is 70 m2/g or more. The powder of the present invention has high strength and is capable of exhibiting superior adsorption capability when it is used for an adsorbent an adsorption apparatus has.

First claim

What is claimed is:

1. A method of producing sintered powder including sintered secondary particles mainly formed of hydroxyapatite, the method comprising:
mixing a first liquid containing a calcium source to be a raw material of the hydroxyapatite with a second liquid containing a phosphoric source to be the raw material of the hydroxyapatite to obtain a mixture;
reacting the calcium source with the phosphoric source with stirring of the mixture to obtain a slurry containing primary particles of the hydroxyapatite and aggregates thereof;
physically crushing the aggregates contained in the slurry such that an average particle size of the crushed aggregates is 1 μm or less to disperse the crushed aggregates in the slurry;
granulating the primary particles and the crushed aggregates by spraying and drying the slurry to obtain secondary particles; and
sintering the secondary particles at a sintering temperature to obtain the sintered powder,
wherein the sintered powder has a compressive particle strength of over about 7.0 MPa.

2. The method as claimed in claim 1 , wherein power for stirring the mixture is in the range of 0.75 W to 2.0 W per 1 L of the mixture.

3. The method as claimed in claim 1 , wherein a content of the calcium source in the first liquid is in the range of 5 wt % to 15 wt % and a content of the phosphoric source in the second liquid is in the range of 10 wt % to 25 wt %.

4. The method as claimed in claim 1 , wherein the mixing the first liquid with the second liquid is performed by dropping the second liquid into the first liquid at a rate of 1 L/hour to 40 L/hour.

5. The method as claimed in claim 4 , wherein a time for dropping the second liquid into the first liquid is in the range of 5 hours to 32 hours.

6. The method as claimed in claim 1 , wherein the physically crushing the aggregates is performed by a wet-type jet mill method in which the slurry is sprayed under a high pressure to obtain droplets of the slurry and the droplets are crashed to each other such that the average particle size of the crushed aggregates is in the range of 0.1 μm to 0.74 μm.

7. The method as claimed in claim 1 , wherein the physically crushing the aggregates is performed such that the average particle size of the crushed aggregates is in the range of 0.1 μm to 0.74 μm.

8. The method as claimed in claim 1 , wherein an average particle size of the secondary particles is in the range of 2 μm to 100 μm.

9. The method as claimed in claim 1 , wherein an average particle size of the secondary particles is in the range of 3 μm to 10 μm.

10. The method as claimed in claim 1 , wherein a bulk density of the powder is 0.65 g/mL or more and a specific surface area of the secondary particles is 70 m 2 /g or more.

11. Powder comprising secondary particles mainly formed of hydroxyapatite, wherein the powder is formed by the method of claim 1 .

12. The method as claimed in claim 1 , wherein the powder has a repose angle of about 22° to about 27°.

13. The method as claimed in claim 1 , wherein the powder has a sphericity of about 0.95 to about 1.00.

14. A method of producing sintered powder including sintered secondary particles mainly formed of hydroxyapatite, the method comprising:
mixing a first liquid containing a calcium source to be a raw material of the hydroxyapatite with a second liquid containing a phosphoric source to be the raw material of the hydroxyapatite to obtain a mixture;
reacting the calcium source with the phosphoric source with stirring the mixture to obtain a slurry containing primary particles of the hydroxyapatite and aggregates thereof;
physically crushing the aggregates contained in the slurry to disperse the crushed aggregates in the slurry;
granulating the primary particles and the crushed aggregates by spraying and drying the slurry to obtain the secondary particles; and
sintering the secondary granulated particles at a sintering temperature to obtain the sintered powder, wherein the sintered powder has a compressive particle strength of over about 7.0 MPa.

15. The method as claimed in claim 14 , wherein the powder has a repose angle of about 22° to about 27°.

16. The method as claimed in claim 14 , wherein the powder has a sphericity of about 0.95 to about 1.00.

Assignees

• Hoya Corp

Inventors

• Kobayashi Shintaro

Classifications

• B01J20/28069

  Pore volume, e.g. total pore volume, mesopore volume, micropore volume · CPC title

• B01J20/3021

  Milling, crushing or grinding · CPC title

• B01J20/28059

  being less than 100 m2/g · CPC title

• B01J20/28057

  Surface area, e.g. B.E.T specific surface area · CPC title

• C01B25/32 Primary

  Phosphates of magnesium, calcium, strontium, or barium · CPC title