US3798875A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of hydrogen fluoride
Assignee: Imperial Chemical Industries Ltd
•
Filing: 1972-02-22
•
Granted: 1974-03-26
•
Expires: 1992-02-22
Abstract
Abstract Hydrogen fluoride is recovered from a gaseous mixture containing it by passing the gaseous mixture through a mixture of an alkalimetal fluoride in an inert liquid maintained at a temperature at which the hydrogen fluoride is absorbed and thereafter heating the mixture to a temperature sufficient to liberate hydrogen fluoride.
Inventors
- 👤 G Morris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:48
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/14; B01D53/1493; B01D53/34; B01D53/46; B01D53/68
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
66 words
A process according to claim 1 wherein the process is carried out continuously and the gaseous mixture is passed to the suspension in a first stage where the gaseous mixture is absorbed by the suspension, the suspension of the first stage is heated in a second stage to liberate the hydrogen fluoride and regenerate the suspension and the regenerated suspension is recycled to the first stage.
Claim 2
Dependent Claim
14 words
A process according to claim 1 in which the alkali-metal fluoride is sodium fluoride.
Claim 3
Dependent Claim
24 words
A process according to claim 1 in which the alkali-metal fluoride comprises 1 to 50 percent by weight of the mixture with the liquid.
Claim 4
Dependent Claim
21 words
A process according to claim 4 in which the alkali-metal fluoride comprises 15 to 25 percent by weight of the mixture.
Claim 5
Dependent Claim
25 words
A process according to claim 1 in which the mixture is maintained at a temperature of 70* to 180*C whilst the hydrogen fluoride is absorbed.
Claim 6
Dependent Claim
14 words
A process according to claim 6 in which the temperature is 110* to 130*C.
Claim 7
Dependent Claim
25 words
A process according to claim 1 in which the mixture has been heated to a temperature of 240* to 280*C to liberate the hydrogen fluoride.
Claim 8
Dependent Claim
19 words
A process according to claim 1 in which the hydrogen fluoride is recovered from a gaseous mixture containing water.
Claim 9
Dependent Claim
18 words
A process according to claim 9 in which the gaseous mixture is obtained by the pyrohydrolysis of fluorspar.
Claim 10
Dependent Claim
27 words
A process according to claim 1 in which the liquid with which the alkali-metal fluoride is mixed is one which does not appreciably dissolve the alkali-metal fluoride.
Claim 11
Dependent Claim
26 words
A process according to claim 1 in which the liquid with which the alkali metal fluoride is mixed is one which is substantially immiscible with water.
Claim 12
Dependent Claim
22 words
A process according to claim 1 in which the liquid with which the alkali-metal fluoride is mixed is a high-boiling aromatic compound.
Claim 13
Dependent Claim
19 words
A process according to claim 13 in which the liquid is diphenyl, diphenyl ether or a mixture of these.
Claim 14
Dependent Claim
13 words
A process according to claim 13 in which the liquid is chlorinated diphenyl.
Claim 15
Dependent Claim
35 words
A process according to claim 1 in which the liquid with which the alkali-metal fluoride is mixed is di-n-butyl phthalate, polypropylene glycol, mineral oil, oleic acid or a mixture of two or more of these.
References Cited (Backward Citations)
US2426558A
Cited
US2858901A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |