US3758266A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Calcining process and installation
Assignee: Individual
•
Filing: 1972-06-23
•
Granted: 1973-09-11
•
Expires: 1992-06-23
Abstract
Abstract A phosphate or like mineral material is calcined in a rotary kiln after having been dried and preheated to a temperature lower than the normal reaction temperature of the material. The preheated material is introduced into the hottest zone of the kiln and passed therethrough in the same direction as hot calcining gases. The calcined material is cooled with a current of fresh air, a portion of the cooling air is mixed with the gases removed from the kiln, and the gas mixture is used to preheat the material.
Inventors
- 👤 R Retali
- 👤 P Pithois
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:03
CPC Classifications
C; C01; C01B; C01B25/00; C01B25/01; F; F27; F27B; F27B7/00; F27B7/20; F27B7/2016; F27B7/2025; F27B7/38; F27B7/383
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
21 words
passing the raw material and hot gases in contact therewith through the kiln in the same direction to calcine the material,
Claim 2
Dependent Claim
23 words
The calcining process of claim 1, wherein a portion of the preheating gas mixture is returned after use for preheating the raw material.
Claim 3
Dependent Claim
4 words
a tubular rotary kiln,
Claim 4
Dependent Claim
66 words
The calcining process of claim 1, wherein the calcined material is first cooled, as it leaves the kiln, by a portion of the preheating gas mixture, this gas mixture portion is then mixed with the gases removed from the kiln, the calcined material is then cooled by the current of air, and a portion of the cooling air is introduced into the kiln as secondary air.
Claim 5
Dependent Claim
10 words
a cyclone cooler for the material calcined in the kiln,
Claim 6
Dependent Claim
10 words
removing the calcined material and the gases from the kiln,
Claim 7
Dependent Claim
13 words
cooling the calcined material removed from the kiln with a current of air,
Claim 8
Dependent Claim
25 words
An installation for calcining a mineral material producing an exothermic reaction at a temperature lower than the maximum temperature of treatment of the material, comprising
Claim 9
Dependent Claim
9 words
an outlet for removing hot gases from the kiln,
Claim 10
Dependent Claim
9 words
an outlet for removing cooling gases from the cooler,
Claim 11
Dependent Claim
40 words
The installation of claim 4, wherein the preheater has a gas inlet and a gas outlEt, and further comprising a return conduit for introducing a portion of the gases removed from the preheater gas outlet to the preheater gas inlet.
Claim 12
Dependent Claim
23 words
mixing a portion of the cooling air with the gases removed from the kiln after the air has cooled the calcined material, and
Claim 13
Dependent Claim
24 words
using the mixture of the cooling air and the removed gases to preheat the raw material before it is introduced into the rotary kiln.
Claim 14
Dependent Claim
37 words
conduit means connecting the kiln outlet and the cooler outlet to the preheater for supplying the hot gases removed from the kiln and a portion of the cooling gases removed from the cooler to the preheater, and
Claim 15
Dependent Claim
31 words
The installation of claim 4, further comprising a drier for the raw material ahead of the preheater, and additional conduit means for supplying gases removed from the preheater to the drier.
Claim 16
Dependent Claim
85 words
The installation of claim 4, wherein the preheater and the cooler each comprises a series of cyclones, and further comprising conduit means for supplying a portion of the gases removed from the preheater to the first one of the cyclones of the cooler which is entered by the calcined material coming from the kiln, said portion of the cooling gases being removed from said first cyclone, and the branch conduit means conducting the cooling gases from the other cyclones of the cooler to the kiln.
Claim 17
Dependent Claim
33 words
a branch conduit means connecting the outlet of the cooler to the kiln for supplying the remainder of the cooling gases removed from the cooler to the kiln for use as secondary air.
References Cited (Backward Citations)
US2663560A
Cited
US3521866A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |