US3998732A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for purifying water of organic compounds not readily biodegradable
Assignee: Feldmuehle Anlagen und Produktion GmbH
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Filing: 1975-10-16
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Granted: 1976-12-21
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Expires: 1995-10-16
Abstract
Abstract The waste water of a sulfite pulp mill containing lignin and lignin derivatives which are not bio-degradable is purified by contact with a fixed bed of granular, porous gamma -alumina having a particle size of 0.5-10 mm and a specific surface area of at least 140 m2/g.
Inventors
- 👤 Hermann Solbach
- 👤 Hans Foerster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:37
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/28; C02F1/281
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
59 words
A method of purifying contaminated waste water, from paper and pulp mills of organic impurities substantially not biodegradable which comprises contacting said waste water with granular, porous γ-alumina until said impurities are adsorbed on said alumina, said alumina having a particle size of 0.5 to 10 mm and a specific surface area of at least 140 m 2 /g.
Claim 2
Independent Claim
59 words
A method of purifying contaminated waste water, from paper and pulp mills of organic impurities substantially not biodegradable which comprises contacting said waste water with granular, porous γ-alumina until said impurities are adsorbed on said alumina, said alumina having a particle size of 0.5 to 10 mm and a specific surface area of at least 140 m 2 /g.
Claim 3
Dependent Claim
18 words
A method as set forth in claim 1, wherein said particle size is between 3 and 6 mm.
Claim 4
Dependent Claim
24 words
A method as set forth in claim 2, wherein the pores in said alumina have a volume of at least 0.35 cm 3 /g.
Claim 5
Dependent Claim
23 words
A method as set forth in claim 3, wherein the particles of said alumina have a breaking strength of at least 2.5 kg.
Claim 6
Dependent Claim
24 words
A method as set forth in claim 4, wherein said alumina contains more than 97% Al 2 O 3 on a bone dry basis.
Claim 7
Dependent Claim
35 words
A method as set forth in claim 1, wherein said waste water is contacted with said alumina by moving said water relative to said alumina at a velocity of 3 to 10 meters per hour.
Claim 8
Dependent Claim
33 words
A method as set forth in claim 1, wherein said alumina is stripped of adsorbed impurities after said contacting by heating in air at 500° to 600° C for 40 to 60 minutes.
Claim 9
Dependent Claim
24 words
A method as set forth in claim 1, wherein said waste water, prior to said contacting, is adjusted to a pH value below 4.5.
Claim 10
Dependent Claim
26 words
A method as set forth in claim 8, wherein said impurities include as a major component derivatives of lignin having a molecular weight greater than 6,000.
References Cited (Backward Citations)
US2758070A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-12-21 | 1980-06-21 | 1980-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-12-21 | 1984-06-21 | 1984-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-12-21 | 1988-06-21 | 1988-12-21 | $7700.00 | Window Closed / Lapsed |