US4017589A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of ammonium polyphosphates from melamine phosphates
Assignee: Tennessee Valley Authority
•
Filing: 1976-03-17
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Granted: 1977-04-12
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Expires: 1996-03-17
Abstract
Abstract Ammonium polyphosphates are prepared by a process which comprises heating melamine orthophosphate prepared from impure wet-process phosphoric acid in a stream of gaseous ammonia at a temperature between 150 DEG C and 210 DEG C to produce a mixture of melamine and relatively pure short-chain ammonium polyphosphates. The solid product is extracted with water to remove the ammonium polyphosphates and free the insoluble, crystalline melamine for recycle. Thus, the only starting materials consumed in the process are phosphoric acid and ammonia.
Inventors
- 👤 John F. McCullough
- 👤 Richard C. Sheridan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:14
CPC Classifications
C; C05; C05B; C05B13/00; C05B13/06; C01; C01B; C01B25/00; C01B25/16; C01B25/26; C01B25/28; C01B25/38; C01B25/40; C01B25/405
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
74 words
A process for manufacturing short-chain ammonium polyphosphates, which process comprises the steps of: 1. heating melamine orthosphosphate in an atmosphere of ammonia to a temperature between 150° and 210° C for a predetermined time sufficient to convert said melamine phosphate to crystalline melamine and ammonium polyphosphates; 2. separating said crystals of melamine formed by the reaction of said ammonia with said melamine orthophosphate in step 1, supra, and recovering said ammonium polyphosphates as product.
Claim 2
Dependent Claim
74 words
A process for manufacturing short-chain ammonium polyphosphates, which process comprises the steps of: 1. heating melamine orthosphosphate in an atmosphere of ammonia to a temperature between 150° and 210° C for a predetermined time sufficient to convert said melamine phosphate to crystalline melamine and ammonium polyphosphates; 2. separating said crystals of melamine formed by the reaction of said ammonia with said melamine orthophosphate in step 1, supra, and recovering said ammonium polyphosphates as product.
Claim 3
Dependent Claim
16 words
The process of claim 1 in which the melamine orthophosphate is derived from wet-process phosphoric acid.
Claim 4
Dependent Claim
19 words
The process of claim 1 in which the product is a mixture of short-chain ammonium polyphosphates and ammonium orthophosphate.
Claim 5
Dependent Claim
15 words
The process of claim 1 in which the temperature ranges between 175° and 200° C.
Claim 6
Dependent Claim
18 words
The process of claim 1 in which the time ranges between about 10 minutes and about 90 minutes.
Claim 7
Dependent Claim
39 words
The process of claim 1 wherein said atmosphere of ammonia is maintained over the melamine orthophosphate material by means of continuously sweeping said area with a gas containing about 10 volume percent to about 100 volume percent of ammonia.
References Cited (Backward Citations)
US3912802A
Cited
US3920796A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-11 | 1980-10-11 | 1981-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-11 | 1984-10-11 | 1985-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-11 | 1988-10-11 | 1989-04-12 | $7700.00 | Window Closed / Lapsed |