US3287407A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of urea
Assignee: Montedison SpA
•
Filing: 1962-11-23
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Granted: 1966-11-22
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Expires: 1982-11-23
Abstract
No abstract record available.
Inventors
- 👤 Zardi Umberto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:49
CPC Classifications
C; C05; C05C; C05C9/00; C05C9/005; C07; C07C; C07C273/00; C07C273/02; C07C273/14; C07C273/16
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
96 words
A PROCESS FOR PRODUCING HIGH PURITY UREA, WITH A LOW BIURET AND AMMONIA CONTENT, WHICH COMPRISES MIXING WITH SUBSTANTIALLY ANHYDROUS MOLTEN UREA CONTAINING BIURET AND FREE AMMONIA, 0.5 TO 3 G. DRY AMMONIA PER KILOGRAM OF UREA AT A PRESSURE OF TWO TO FIFTEEN ATMOSPHERES, PASSING SAID MIXTURE THROUGH AN AMMONIATION ZONE AT 120*C. TO 150*C. AND TWO TO FIFTEEN ATMOSPHERES FOR A DWELL TIME OF ABOUT 30 TO 900 SECONDS IN SAID AMMONIATION ZONE AND STRIPPING RESIDUAL AMMONIA BY HOT AIR AT ABOUT ATMOSPHERIC PRESSURE TO GIVE UREA WITH A REDUCED BIURET AND AMMONIA CONTENT.
Claim 2
Dependent Claim
96 words
A PROCESS FOR PRODUCING HIGH PURITY UREA, WITH A LOW BIURET AND AMMONIA CONTENT, WHICH COMPRISES MIXING WITH SUBSTANTIALLY ANHYDROUS MOLTEN UREA CONTAINING BIURET AND FREE AMMONIA, 0.5 TO 3 G. DRY AMMONIA PER KILOGRAM OF UREA AT A PRESSURE OF TWO TO FIFTEEN ATMOSPHERES, PASSING SAID MIXTURE THROUGH AN AMMONIATION ZONE AT 120*C. TO 150*C. AND TWO TO FIFTEEN ATMOSPHERES FOR A DWELL TIME OF ABOUT 30 TO 900 SECONDS IN SAID AMMONIATION ZONE AND STRIPPING RESIDUAL AMMONIA BY HOT AIR AT ABOUT ATMOSPHERIC PRESSURE TO GIVE UREA WITH A REDUCED BIURET AND AMMONIA CONTENT.
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) | 1969-11-21 | 1970-05-23 | 1970-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-11-21 | 1974-05-23 | 1974-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-11-21 | 1978-05-23 | 1978-11-22 | $7700.00 | Window Closed / Lapsed |