US2772965A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of chemicals in wood pulp preparation
Assignee: Rayonier Inc
•
Filing: 1953-06-02
•
Granted: 1956-12-04
•
Expires: 1973-06-02
Abstract
No abstract record available.
Inventors
- 👤 Gray Kenneth Russell
- 👤 Crosby Hartzell Lance
- 👤 Steinberg John Charles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:27
CPC Classifications
D; D21; D21C; D21C11/00; D21C11/0064; D21C11/0071; Y; Y10; Y10S; Y10S423/00; Y10S423/03
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
97 words
IN THE PROCESS OF PREPARING WOOD PULP WHEREIN AN ALKALINE DIGESTION IS CARRIED OUT WITH A SODIUM SULFIDECONTAINING SOLUTION AND IN WHICH SULFIDE-CONTAINING WASTE BLACK LIQUOR IS EVAPORATED AND BURNED TO PRODUCE A SMELT FOR THE RECOVERY OF CHEMICALS, THE IMPROVEMENT WHICH COMPRISES CARBONATING THE WASTE BLACK LIQUOR WITH CARBON DIOXIDE UNDER PRESSURE AND THEN STRIPPING HYDROGEN SULFIDE FROM THE CARBONATED LIQUOR UNDER A VACUUM REDUCING THE SULFIDE SULFUR CONTENT OF THE LIQUOR SUBSTANTIALLY, THEREBY REDUCING SULFUR LOSSES, RECOVERING CONCENTRATED HYDROGEN SULFIDE, AND MINIMIZING OBNOXIOUS ODORS, AND THEN EVAPORATING THE STRIPPED LIQUOR AND BURNING THE RESULTING CONCENTRATE.
Claim 2
Dependent Claim
97 words
IN THE PROCESS OF PREPARING WOOD PULP WHEREIN AN ALKALINE DIGESTION IS CARRIED OUT WITH A SODIUM SULFIDECONTAINING SOLUTION AND IN WHICH SULFIDE-CONTAINING WASTE BLACK LIQUOR IS EVAPORATED AND BURNED TO PRODUCE A SMELT FOR THE RECOVERY OF CHEMICALS, THE IMPROVEMENT WHICH COMPRISES CARBONATING THE WASTE BLACK LIQUOR WITH CARBON DIOXIDE UNDER PRESSURE AND THEN STRIPPING HYDROGEN SULFIDE FROM THE CARBONATED LIQUOR UNDER A VACUUM REDUCING THE SULFIDE SULFUR CONTENT OF THE LIQUOR SUBSTANTIALLY, THEREBY REDUCING SULFUR LOSSES, RECOVERING CONCENTRATED HYDROGEN SULFIDE, AND MINIMIZING OBNOXIOUS ODORS, AND THEN EVAPORATING THE STRIPPED LIQUOR AND BURNING THE RESULTING CONCENTRATE.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-12-04 | 1960-06-04 | 1960-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-12-04 | 1964-06-04 | 1964-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-12-04 | 1968-06-04 | 1968-12-04 | $7700.00 | Window Closed / Lapsed |