US4407967A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing spheroidal ceramics
Assignee: FRENCHTOWN AMERICAN Corp A CORP OF NJ
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Filing: 1981-03-05
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Granted: 1983-10-04
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Expires: 2001-03-05
Abstract
Abstract Spray dried spheroidal ceramic particles are fired at about 100° to 150° (C.) less than the optimum firing temperature, so as to achieve about 95% of theoretical density while avoiding more than nominal co-sintering (e.g. sticking together). The fired spheroidal ceramics are useful as such in a variety of applications, and can also be pressed into shapes and re-fired to form porous ceramic filter elements of closely controlled permeability.
Inventors
- 👤 Daniel W. Luks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:46
CPC Classifications
C; C04; C04B; C04B38/00; C04B38/0038; B; B01; B01D; B01D39/00; B01D39/14; B01D39/20; B01D39/2068; B01D39/2072; B01D39/2075; C04B14/00; C04B14/02; C04B14/04; C04B14/10; C04B2111/00; C04B2111/00474; C04B2111/00793
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
85 words
The method of producing spheroidal ceramic particles comprising: preparing a ceramic slip including particles of a particular composition and known curing temperature; forming green, spheroidal ceramic particles by spray drying said slip; firing said green particles at about 100° to 150° C. below the optimum curing temperature to produce spheroidal particles of less than maximum bulk density and to avoid any substantial sintering together of said particles; and agitating the fired particles to separate particles that have sintered together during firing into individual spheroidal particles.
Claim 2
Independent Claim
85 words
The method of producing spheroidal ceramic particles comprising: preparing a ceramic slip including particles of a particular composition and known curing temperature; forming green, spheroidal ceramic particles by spray drying said slip; firing said green particles at about 100° to 150° C. below the optimum curing temperature to produce spheroidal particles of less than maximum bulk density and to avoid any substantial sintering together of said particles; and agitating the fired particles to separate particles that have sintered together during firing into individual spheroidal particles.
Claim 3
Dependent Claim
19 words
The method as claimed in claim 1, wherein said agitation and separation of particles is carried out by mulling.
Claim 4
Dependent Claim
10 words
Spheroidal ceramic particles produced by the method of claim 1.
Claim 5
Independent Claim
129 words
The method of producing porous ceramic bodies comprising: preparing a ceramic slip including particles of a particular composition and known curing temperature; forming green, spheroidal ceramic particles by spray drying said slip; firing said green particles at about 100° to 150° C., below the optimum curcing temperature to produce particles of less than maximum bulk density and to avoid any substantial sintering together of said particles; and agitating the fired particles to separate particles that have sintered together during firing into individual spheroidal particles; classifying the separated, fired particles into size fractions; mixing a fraction of the fired particles with a binder material; forming the particle-binder mixture into a body of desired shape; and firing the shaped body at the optimum curing temperature to produce a porous ceramic body.
Claim 6
Independent Claim
129 words
The method of producing porous ceramic bodies comprising: preparing a ceramic slip including particles of a particular composition and known curing temperature; forming green, spheroidal ceramic particles by spray drying said slip; firing said green particles at about 100° to 150° C., below the optimum curcing temperature to produce particles of less than maximum bulk density and to avoid any substantial sintering together of said particles; and agitating the fired particles to separate particles that have sintered together during firing into individual spheroidal particles; classifying the separated, fired particles into size fractions; mixing a fraction of the fired particles with a binder material; forming the particle-binder mixture into a body of desired shape; and firing the shaped body at the optimum curing temperature to produce a porous ceramic body.
Claim 7
Dependent Claim
14 words
The method as claimed in claim 4, wherein said binder is a wax emulsion.
Claim 8
Dependent Claim
12 words
The method as claimed in claim 4, wherein said binder is wax.
Claim 9
Dependent Claim
43 words
The method as claimed in claim 4, and additionally comprising: adding a controlled amount of green particles of a smaller size fraction and the same composition as said fired particles to said fired-particle-binder mixture, whereby porosity of said ceramic body is controllably reduced.
Claim 10
Dependent Claim
10 words
Porous ceramic bodies produced by the method of claim 4.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-03 | 1987-04-04 | 1987-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-03 | 1991-04-04 | 1991-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-03 | 1995-04-04 | 1995-10-04 | $7700.00 | Window Closed / Lapsed |