Expanded mineral particles and apparatus and method of production

• US 5,002,696 A
• Filed: 08/01/1988
• Issued: 03/26/1991
• Est. Priority Date: 08/01/1988
• Status: Expired due to Term

• Current Assignee: Grefco, Inc. (American Greetings Corporation)
• Original Assignee: Grefco, Inc. (American Greetings Corporation)
• Inventors: White, William R.
• Primary Examiner(s): Straub, Gary P.
• Application Number:
  US07/226,956
• Time in Patent Office: 967 Days
• Field of Search: 252/378 R, 252/378 P, 501/33, 501/34, 106/409, 106/DIG. 2
• US Class Current: 252/378.00R
• CPC Class Codes: B01J 6/008 Pyrolysis reactions of hydrocarbons C10G9/00
• CPC Class Codes: C04B 14/02 Granular materials , e.g. microballoons
• CPC Class Codes: C04B 14/14 Minerals of vulcanic origin granite C04B14/048
• CPC Class Codes: C04B 14/16 porous, e.g. pumice
• CPC Class Codes: C04B 20/002 Hollow or porous granular materials
• CPC Class Codes: C04B 20/06 Expanding clay, perlite, vermiculite or like granular materials
• CPC Class Codes: C04B 20/066 in shaft or vertical furnaces
• CPC Class Codes: C04B 20/10 Coating or impregnating roofing granules E04D7/005
• CPC Class Codes: C08K 7/24 inorganic
• CPC Class Codes: F27B 9/142 the charge moving along a vertical axis
• CPC Class Codes: F27D 3/0033 charging of particulate material
• CPC Class Codes: Y10S 106/02 Perlite

Abstract

A non-porous, substantially hollow, expanded mineral product, such as expanded perlite, is produced by uniformly and indirectly heating ore for about 1 to 30 seconds in an expansion chamber maintained at about 1400° F.-2100° F. to produce uncoated particles which exhibit superior short term and long term density stability characterics in liquid systems, and which may subsequently be coated to provide enhanced density stability characteristics.

Claims

1. An expanded mineral product comprising:

mineral particles made from the group consisting of perlite, pumice, pumicite, pitchstone, obsidian and volcanic ash and which have been expanded to a greater volume then the volume of the particles prior to expansion,

said expanded mineral product particles being uncoated, having a substantially smooth, non-porous surface and a nominal density less than about 2.0 gram/cc. as measured by air comparison pycnometer, and

said particles having the property that when mixed with an emulsion or liquid which is chemically inert to said particles and which has a viscosity in the range of about 25,000 to 100,000 centipoise and at about 2% by weight of said particles to said liquid to form a mixture, said mixture is subjected to a vacuum of about 25" Hg for 10 minutes and then released, the density change of said liquid is less than 10%.

2. The expanded mineral product of claim 1 which when mixed with the liquid or emulsion to form the mixture to which the 10-minute vacuum is applied, results in a mixture density change of less than 5%.

3. The expanded mineral product of claim 1 which, mixed with the liquid or emulsion to form the mixture to which the 10-minute vacuum is applied, results in a mixture density change of between 1% and 8%.

4. The expanded mineral product of claim 1 which, when mixed with the liquid to form the mixture held at a temperature of about 120°

F. for one month, results in a mixture density change of between 1% and 8%.

5. The expanded mineral product of claim 1, said particles having the additional property that

when mixed with a liquid which is chemically inert to said particles and which has a viscosity in the range of 25,000 to 100,000 centipoise and at about 2% by weight of said particles to said liquid to form a mixture and said mixture is held at a temperature of 120°

F. for one month,

results in a mixture density change of less than 10%.

8. The expanded mineral product of any of claims 1, 5 or 6 having a nominal density of about 0.05-2.0 gm/cc as measured by air comparison pycnometer.

9. The expanded mineral product of any of claims 1, 5 or 6 having a nominal density of 0.10-1.0 gm/cc as measured by air comparison pycnometer.

10. The expanded mineral product of any of claims 1, 5 or 6 having a nominal density of 0.15-0.70 gm/cc as measured by air comparison pycnometer.

11. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size below 9520 microns.

12. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size within the range of 5-9520 microns.

13. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles having a particle size below 1000 microns.

14. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles having a particle size within the range 5-1,000 microns.

15. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size below 840 microns.

16. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size within the range 5-840 microns.

17. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size below 210 microns.

18. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size within the range 5-210 microns.

19. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size below 149 microns.

20. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size within 3-149 microns.

21. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size below 105 microns.

22. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size within the range of 3-105 microns.

23. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size below 44 microns.

24. The expanded mineral product of any of claims 1, 5 or 6 wherein the expanded mineral particles have a particle size within the range of 3-53 microns.

25. The expanded mineral product of any of claims 1, 5 or 6, said particles further having

a substantially spherical shape.

26. The expanded mineral product of any of claims 1, 5 or 6, said particles further having

a substantially continuous, spherical surface and a hollow interior.

6. An expanded mineral product comprising:

mineral particles made from the group consisting of perlite, pumice, pumicite, pitchstone, obsidian and volcanic ash and which have been expanded to a greater volume than the volume of the particles prior to expansion,

said particles being uncoated, having a substantially smooth, non-porous surface and a nominal density less than 2.0 gram/cc as measured by air comparison pycnometer, and

said particles having the property that when mixed with a liquid which is chemically inert to said particles and having a viscosity between 25,000 and 100,000 centipoise and at about 2% by weight of said liquid to form a mixture and said mixture is held at a temperature of 120°

F. for one month,

results in a mixture density change of less than 10%.

7. The expanded mineral product of claim 6 which, when mixed with the liquid to form the mixture held at the temperature of about 120°

F. for one month, results in a mixture density change of less than 5%.