Patent US3888967A successfully refreshed from Google Patents.
US3888967A
Expired / Lapsed
US
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Method and apparatus for oxidizing sulphide-containing aqueous solutions
Assignee: Svenska Cellulosa AB
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Filing: 1973-02-09
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Granted: 1975-06-10
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Expires: 1993-02-09
Abstract
Abstract In oxidizing sulphides contained in alkaline aqueous solutions by an oxygen-containing gas, the unwanted production of hydrogen sulphide is prevented by effecting the oxidation in the presence of finely divided active carbon and with vigorous stirring.
Inventors
- 👤 Per-Erik Andersson
- 👤 Einar Horntvedt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:02
CPC Classifications
C; C01; C01B; C01B17/00; C01B17/64; C01B17/02; C01B17/06; Y; Y10; Y10S; Y10S423/00; Y10S423/03
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
176 words
A METHOD OF CONVERTING TO A NON-VOLATILE REACTION PRODUCT COMPRISING SODIUM THIOSULPHATE THE SODIUM SULPHIDE CONTENT OF SODA SOLUTION CONTAINING FINELY DIVIDED ACTIVE CARBON OBTAINED BY RECOVERING CHEMICALS FROM WASTE LIQUOR FROM THE DIGESTION OF LIGNOCELLULOSIC MATERIAL, IN WHICH RECOVERY PROCESS THE WASTE LIQUOR IS EVAPORATED TO A CONTENT OF SOLID MATERIAL OF AT LEAST 40%, AND THEREAFTER IS PYROLYZED AT A TEMPERATURE OF 700*-800*C. UNDER REDUCING CONDITIONS FOR THE PRODUCTION OF A COMBUSTIBLE GAS AND A SOLID RESIDUE AND CONTAINING ACTIVE CARBON FROM THE PYROLYZING STEP, SODIUM CARBONATE AND SODIUM SULPHIDE, ACCORDING TO WHICH METHOD SAID SOLID RESIDUE IS SEPARATED AND DISPERSED IN WATER, THE DISPERSION IS OXIDIZED BY MEANS OF AN OXYGEN-CONTAINING GAS, UNDER STIRRING, THE AMOUNT OF ACTIVE CARBON IN THE DISPERSION AMOUNTING TO FORM 1 TO 150 GRAMS OF AN OXYGEN-CONTAINING GAS, UNDER STIRRING, THE INTRODUCED INTO THE BODY OF THE SOLUTION, AT A LOCUS ADJACENT THE BOTTOM OF THE BODY, AT A TEMPERATURE OF 10*-90*C, THE GAS BEING MAINTAINED IN INTIMATE CONTACT WITH THE SOLUTION FOR A PERIOD OF 2-40 MINUTES.
Claim 2
Independent Claim
176 words
A METHOD OF CONVERTING TO A NON-VOLATILE REACTION PRODUCT COMPRISING SODIUM THIOSULPHATE THE SODIUM SULPHIDE CONTENT OF SODA SOLUTION CONTAINING FINELY DIVIDED ACTIVE CARBON OBTAINED BY RECOVERING CHEMICALS FROM WASTE LIQUOR FROM THE DIGESTION OF LIGNOCELLULOSIC MATERIAL, IN WHICH RECOVERY PROCESS THE WASTE LIQUOR IS EVAPORATED TO A CONTENT OF SOLID MATERIAL OF AT LEAST 40%, AND THEREAFTER IS PYROLYZED AT A TEMPERATURE OF 700*-800*C. UNDER REDUCING CONDITIONS FOR THE PRODUCTION OF A COMBUSTIBLE GAS AND A SOLID RESIDUE AND CONTAINING ACTIVE CARBON FROM THE PYROLYZING STEP, SODIUM CARBONATE AND SODIUM SULPHIDE, ACCORDING TO WHICH METHOD SAID SOLID RESIDUE IS SEPARATED AND DISPERSED IN WATER, THE DISPERSION IS OXIDIZED BY MEANS OF AN OXYGEN-CONTAINING GAS, UNDER STIRRING, THE AMOUNT OF ACTIVE CARBON IN THE DISPERSION AMOUNTING TO FORM 1 TO 150 GRAMS OF AN OXYGEN-CONTAINING GAS, UNDER STIRRING, THE INTRODUCED INTO THE BODY OF THE SOLUTION, AT A LOCUS ADJACENT THE BOTTOM OF THE BODY, AT A TEMPERATURE OF 10*-90*C, THE GAS BEING MAINTAINED IN INTIMATE CONTACT WITH THE SOLUTION FOR A PERIOD OF 2-40 MINUTES.
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) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |