US4080249A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Delignification and bleaching of a lignocellulosic pulp slurry with ozone
Assignee: International Paper Co
•
Filing: 1976-07-16
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Granted: 1978-03-21
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Expires: 1996-07-16
Abstract
Abstract A process for the delignification and bleaching of a lignocellulosic pulp slurry, having a consistency between about 1% and 10%, by weight of oven-dried pulp, and a pH between about 1 and 7, while at a temperature between about 0° C. and 70° C., with a gaseous mixture selected from the group consisting of ozone/oxygen, ozone/air, and a mixture thereof. The ozone containing gaseous mixture, which has an ozone concentration of from about 0.1% to about 20%, by weight of oxygen or air, is bubbled into the pulp slurry, while agitating the pulp slurry at a rate of about 0.01 to 5.0 horsepower-days per ton of pulp.
Inventors
- 👤 Arthur W. Kempf
- 👤 Richard B. Phillips
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:34
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/1073
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
133 words
A process for delignifying and bleaching lignocellulosic pulp, which comprises reacting a lignocellulosic pulp slurry, having a consistency of from about 1% to about 10%, by weight of oven-dried pulp, and a pH within the range of from about 1 to about 7 and a temperature between about 0° C. and about 70° C., with a gaseous mixture selected from the group consisting of ozone/oxygen, ozone/air, and a mixture thereof, in a reaction vessel, said gaseous mixture being in the form of bubbles substantially all of which are about 1/8 inch or less in diameter and having an ozone concentration of from about 0.1% to about 20%, by weight of oxygen or air, while agitating the pulp slurry at a rate of from about 0.01 to about 5.0 horsepower-days per ton of pulp.
Claim 2
Dependent Claim
133 words
A process for delignifying and bleaching lignocellulosic pulp, which comprises reacting a lignocellulosic pulp slurry, having a consistency of from about 1% to about 10%, by weight of oven-dried pulp, and a pH within the range of from about 1 to about 7 and a temperature between about 0° C. and about 70° C., with a gaseous mixture selected from the group consisting of ozone/oxygen, ozone/air, and a mixture thereof, in a reaction vessel, said gaseous mixture being in the form of bubbles substantially all of which are about 1/8 inch or less in diameter and having an ozone concentration of from about 0.1% to about 20%, by weight of oxygen or air, while agitating the pulp slurry at a rate of from about 0.01 to about 5.0 horsepower-days per ton of pulp.
Claim 3
Dependent Claim
26 words
A process of accordance with claim 1 wherein the concentration of the ozone is from about 2.0% to about 3.0%, by weight of oxygen or air.
Claim 4
Dependent Claim
26 words
A process in accordance with claim 1 wherein from about 0.1% to about 5.0% ozone, by weight of oven-dried pulp, is applied to the pulp slurry.
Claim 5
Dependent Claim
21 words
A process in accordance with claim 1 wherein the time of reaction is from about 1 minute to about 60 minutes.
Claim 6
Dependent Claim
24 words
A process in accordance with claim 1 wherein the agitation utilizes between about 0.1 horsepower-days to about 1.0 horsepower-days per ton of lignocellulosic pulp.
Claim 7
Dependent Claim
23 words
A process in accordance with claim 1 wherein the pulp consistency is from about 2% to about 3%, by weight of oven-dried pulp.
Claim 8
Dependent Claim
22 words
A process in accordance with claim 1 wherein the temperature of the slurry is from about 20° C to about 30° C.
Claim 9
Dependent Claim
20 words
A process in accordance with claim 1 wherein the pH of the pulp slurry is between about 3 and 5.
Claim 10
Dependent Claim
27 words
A process in accordance with claim 1 wherein said pulp slurry is subjected to oxygen bleaching in the presence of alkali prior to said reaction with ozone.
Claim 11
Dependent Claim
17 words
A process in accordance with claim 1 wherein said pulp slurry is subsequently bleached with peracetic acid.
Claim 12
Dependent Claim
18 words
A process in accordance with claim 1 wherein said pulp slurry is subsequently bleached with a peroxide compound.
Claim 13
Dependent Claim
47 words
A process in accordance with claim 1 wherein said pulp slurry, subsequent to said zone reacting, is subjected to the following bleaching sequence: extraction with sodium hydroxide or water, bleaching with an ozone containing gaseous mixture in accordance with claim 1 and then bleaching with peracetic acid.
Claim 14
Dependent Claim
48 words
A process in accordance with claim 1 wherein said pulp slurry, subsequent to said ozone reacting, is subjected to the following bleaching sequence: extraction with sodium hydroxide or water, bleaching with an ozone containing gaseous mixture in accordance with claim 1 and then bleaching with a peroxide compound.
Claim 15
Dependent Claim
47 words
A process in accordance with claim 1 wherein said pulp slurry, subsequent to said ozone reacting, is subjected to the following bleaching sequence: extraction with sodium hydroxide or water, bleaching with an ozone containing gaseous mixture in accordance with claim 1 and then bleaching with chlorine dioxide.
Claim 16
Dependent Claim
48 words
A process in accordance with claim 1 wherein said pulp slurry, subsequent to said ozone reacting, is subjected to the following bleaching sequence: extraction with sodium hydroxide or water, bleaching with an ozone containing gaseous mixture in accordance with claim 1 and then bleaching with a hypochlorite compound.
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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) | 1981-03-20 | 1981-09-19 | 1982-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-20 | 1985-09-19 | 1986-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-20 | 1989-09-19 | 1990-03-21 | $7700.00 | Window Closed / Lapsed |