US3876497A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Paper mill waste sludge oxidation and product recovery
Assignee: US Filter Zimpro Inc
•
Filing: 1973-07-16
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Granted: 1975-04-08
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Expires: 1993-07-16
Abstract
Abstract Paper mill waste sludges are subjected to wet air oxidation whereby organic materials are converted to innocuous oxidation products, and the inorganic filler materials, e.g., titanium dioxide, clay and the like, are recovered in a form suitable for reuse.
Inventors
- 👤 Clarence A Hoffman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:33
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/63; D21H17/70; D21F; D21F1/00; D21F1/66; Y; Y10; Y10S; Y10S162/00; Y10S162/09; Y10S210/00; Y10S210/928
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
131 words
THE PROCESS FOR SUBSTANTIALLY COMPLETE RECOVERY OF INORGANIC PAPER MAKING FILLER MATERIALS FROM PAPER MILL WASTE SLUDGE, WHICH COMPRISES HEATING SAID WASTE SLUDGE WITH AN OXYGEN CONTAINING GAS AT A TEMPERATURE BETWEEN 160* AND 375*C, AND AT A CORRESPONDING PRESSURE OF BETWEEN 500 AND 3,500 PSIG WHICH WILL MAINTAIN MOST OF THE WATER CONTENT OF THE SLUDGE IN THE LIQUID PHASE, AND A CORRESPONDING OXIDATION TIME OF BETWEEN 0.25 AND 5 HOURS; SEPARATING THE GAS, LIQUID, AND SOLID PHASES; WASHING AND DEWATERING THE SOLID TO GIVE REGENERATED FILLER MATERIAL, FREE OF CELLULOSE FIBERS AND OTHER ORGANIC CONTAMINANTS HAVING A BRIGHTNESS OF AT LEAST ABOUT 80 PERCENT G.E. AND SUITABLE FOR REUSE AS A FILLER MATERIAL REIN THE PAPER MAKING PROCESS, SO THAT SUBSTANTIALLY COMPLETE RECOVERY OF SAID FILLER MATERIALS IS ACHIEVED.
Claim 2
Dependent Claim
131 words
THE PROCESS FOR SUBSTANTIALLY COMPLETE RECOVERY OF INORGANIC PAPER MAKING FILLER MATERIALS FROM PAPER MILL WASTE SLUDGE, WHICH COMPRISES HEATING SAID WASTE SLUDGE WITH AN OXYGEN CONTAINING GAS AT A TEMPERATURE BETWEEN 160* AND 375*C, AND AT A CORRESPONDING PRESSURE OF BETWEEN 500 AND 3,500 PSIG WHICH WILL MAINTAIN MOST OF THE WATER CONTENT OF THE SLUDGE IN THE LIQUID PHASE, AND A CORRESPONDING OXIDATION TIME OF BETWEEN 0.25 AND 5 HOURS; SEPARATING THE GAS, LIQUID, AND SOLID PHASES; WASHING AND DEWATERING THE SOLID TO GIVE REGENERATED FILLER MATERIAL, FREE OF CELLULOSE FIBERS AND OTHER ORGANIC CONTAMINANTS HAVING A BRIGHTNESS OF AT LEAST ABOUT 80 PERCENT G.E. AND SUITABLE FOR REUSE AS A FILLER MATERIAL REIN THE PAPER MAKING PROCESS, SO THAT SUBSTANTIALLY COMPLETE RECOVERY OF SAID FILLER MATERIALS IS ACHIEVED.
Claim 3
Dependent Claim
16 words
A process according to claim 1 in which the oxidation temperature lies between 200.degree. and 320.degree.C.
References Cited (Backward Citations)
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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) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |