Process for producing inorganic microspheres

• US 5,849,055 A
• Filed: 03/07/1997
• Issued: 12/15/1998
• Est. Priority Date: 04/09/1996
• Status: Expired due to Fees

• Current Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Original Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Inventors: Arai, Kiyotaka, Satoh, Masakuni, Yamada, Kenji, Hirano, Hachiro
• Primary Examiner(s): Chin, Peter
• Assistant Examiner(s): Ruller, Jacqueline A.
• Application Number:
  US08/813,067
• Time in Patent Office: 648 Days
• Field of Search: 65/17.3, 65/17.6, 65/21.1, 65/21.3, 65/21.2, 65/21.4, 264/12, 264/13, 264/14, 264/15, 264/434, 501/33, 501/84, 501/85, 502/527
• US Class Current: 65/17.3
• CPC Class Codes: B01J 2/04 in a gaseous medium if combined with suspending the material in a gas, e.g. fluidised beds B01J2/16
• CPC Class Codes: C01B 13/328 by processes making use of emulsions, e.g. the kerosine process
• CPC Class Codes: C01F 7/308 Thermal decomposition of nitrates
• CPC Class Codes: C01P 2004/32 Spheres
• CPC Class Codes: C01P 2004/34 hollow
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C03B 19/1005 Forming solid beads chemical aspects C03C12/00
• CPC Class Codes: C03B 19/1025 Bead furnaces or burners
• CPC Class Codes: C03B 19/107 Forming hollow beads chemical aspects C03C11/002
• CPC Class Codes: C03B 19/108 Forming porous, sintered or foamed beads chemical aspects C03C11/00
• CPC Class Codes: C03C 11/002 Hollow glass particles
• CPC Class Codes: C03C 12/00 Powdered glass C03C8/02 takes precedence; Bead compositions

Abstract

A process for producing inorganic microspheres (solid spheres or hollow spheres), which comprises pulverizing a material by wet pulverization to an average particle size of at most 5 μm to obtain a slurry of a pulverized powder material, spraying the slurry to form liquid droplets, and heating the liquid droplets to fuse or sinter the powder material to obtain inorganic microspheres.

Claims

1. A process for producing inorganic microspheres, which comprises pulverizing a material by wet pulverization with a flammable liquid to an average particle size of at most 5 μ

m to obtain a slurry of a pulverized powder material, spraying the slurry into a gas to form liquid droplets, and heating the liquid droplets to fuse or sinter the powder material to obtain inorganic microspheres.

2. The process for producing inorganic microspheres according to claim 1, wherein the powder material is fused or sintered by combustion of said flammable liquid.

3. The process for producing inorganic microspheres according to claim 1, wherein the flammable liquid is selected from the group consisting of kerosine, light oil and an alcohol.

4. The process for producing inorganic microspheres according to claim 1, wherein spraying the slurry by a two fluid nozzle.

5. The process for producing inorganic microspheres according to claim 4, wherein the gas to be used for spraying is selected from the group consisting of a non-flammable gas, air, oxygen gas containing a non-flammable gas and mixtures thereof.

6. The process for producing inorganic microspheres according to claim 5, wherein the non-flammable gas is selected from the group consisting of carbon dioxide gas, nitrogen gas and combustion exhaust gas.

7. The process for producing inorganic microspheres according to claim 1, wherein the material is pulverized by wet pulverization to an average particle size of at most 3 μ

m.

8. The process for producing inorganic microspheres according to claim 1, wherein the material is a blended powder material prepared by blending a plurality of powder materials which vitrify under heating.

9. The process for producing inorganic microspheres according to claim 1, wherein the material is quartz or silica sand.

10. The process for producing inorganic microspheres according to claim 1, wherein the material contains a powder of a metal oxide having an ultraviolet ray absorbing function or a precursor of said metal oxide.

11. The process for producing inorganic microspheres according to claim 1, wherein the powder material contains a blowing agent which foams under heating, and the powder material fuses to form microballons.