Methods for producing solid ceramic particles using a microwave firing process

Patent metadata

Field	Value
Publication number	US-10428267-B2
Application number	US-201715611236-A
Country	US
Kind code	B2
Filing date	Jun 1, 2017
Priority date	Sep 5, 2014
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

Methods for producing solid, substantially round, spherical and sintered particles from a slurry of a raw material having an alumina content of greater than about 40 weight percent. The slurry is processed to prepare green pellets which are sintered in a furnace with microwave energy at a temperature of 1480 to 1520° C. to produce solid, substantially round, spherical and sintered particles having an average particle size greater than about 200 microns, a bulk density of greater than about 1.35 g/cm 3 , and an apparent specific gravity of greater than about 2.60.

First claim

What is claimed is:

1. A method for forming sintered substantially round and spherical pellets, comprising:
forming substantially round and spherical green pellets from raw materials comprising water and kaolin clay; and
sintering the green pellets in a microwave furnace at a temperature of from about 1350° C. to about 1620° C. for a time at peak temperature of from about 20 to about 200 minutes, to form a proppant having a bulk density of from about 1.3 to about 1.6 g/cm 3 and a crush percent at 7500 psi of from about 1.5 to about 3.5.

2. The method of claim 1 , wherein the proppant has an apparent specific gravity of greater than 2.

3. The method of claim 1 , wherein the proppant has an apparent specific gravity of less than 3.1.

4. The method of claim 1 , wherein the proppant has an apparent specific gravity of about 2.6 to about 2.8.

5. The method of claim 1 , wherein the green pellets are sintered in the microwave furnace at a peak temperature of from about 1480° C. to about 1520° C. for about 20 to about 45 minutes.

6. The method of claim 1 , wherein the substantially round and spherical green pellets are prepared from a slurry having a solids content of from about 40 to about 60% by weight and having an alumina content in a range of from about 40 to about 55% by weight.

7. A method for producing sintered particles comprising:
forming green particles having a moisture content of at least about 5% by weight from a slurry having a solids content of from about 40 to about 60% by weight, and comprising water and a raw material having an alumina content in a range of from about 40 to about 55% by weight;
drying the green particles in a microwave furnace to produce dried green particles having a moisture content of less than 5% by weight; and
sintering the dried green particles at a temperature of from about 1480° C. to about 1520° C. for a time at peak temperature of from about 20 to about 45 minutes, to form sintered particles having a bulk density of from about 1.35 to about 1.60 g/cm 3 and a crush percent at 7500 psi of from about 1.5 to about 3.5.

8. The method of claim 7 , wherein the dried green particles are sintered for about 50 to about 200 minutes.

9. The method of claim 7 , further comprising calcining the dried green pellets in the microwave furnace prior to sintering.

10. The method of claim 7 , wherein the sintering is performed in the microwave furnace.

11. The method of claim 7 , wherein the sintered particles have an apparent specific gravity of about 2.6 to about 2.8.

Assignees

• Carbo Ceramics Inc

Inventors

• Cannan Chad
• Wilson Brett A
• Eldred Benjamin T

Classifications

• C09K8/80

  Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open · CPC title

• C09K8/805 Primary

  Coated proppants · CPC title

• H05B2206/046

  Microwave drying of wood, ink, food, ceramic, sintering of ceramic, clothes, hair · CPC title

• H05B6/80

  Apparatus for specific applications (stoves or ranges F24C7/02) · CPC title

• F26B2210/02

  Ceramic articles or ceramic semi-finished articles · CPC title