US5332474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Conversion of pulp and paper mill waste solids to a papermaking filler product
Assignee: NewPage Wisconsin System Inc
•
Filing: 1993-01-19
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Granted: 1994-07-26
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Expires: 2013-01-19
Abstract
Abstract A process for the production of a papermaking filler product from the fiber fines/clay fraction of a pulp, paper, paperboard, or deinking mill waste solids such process comprising the reaction of said solids with sufficient acid to lower and maintain a pH of less than 5.0. Such process yields improvement in the drainage characteristics of the material. Bleach can be added or the pH raised back to neutral to further improve the specific resistance and/or brightness of the material.
Inventors
- 👤 John V. Maxham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:17
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/001; D21C9/002; D21C9/004; D21H; D21H17/00; D21H17/01; Y; Y10; Y10S; Y10S162/00; Y10S162/09
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
95 words
A process for improving the drainage characteristics of the fiber fines/clay fraction of waste solids generated by a pulp, paper, paperboard or deinking mill such that it is more suitable as a filler for paper, paperboard, and other fibrous product manufacture. said process comprising the steps of: a. separating the fiber fines/clay fraction of the waste solids from the other solids; b. concentrating the fiber fines/clay fraction; and, c. reacting the fiber fines/clay concentrate with sufficient acid to maintain a Ph not more than 5.0 to improve the drainage characteristics of the fiber fines/clay fraction.
Claim 2
Dependent Claim
95 words
A process for improving the drainage characteristics of the fiber fines/clay fraction of waste solids generated by a pulp, paper, paperboard or deinking mill such that it is more suitable as a filler for paper, paperboard, and other fibrous product manufacture. said process comprising the steps of: a. separating the fiber fines/clay fraction of the waste solids from the other solids; b. concentrating the fiber fines/clay fraction; and, c. reacting the fiber fines/clay concentrate with sufficient acid to maintain a Ph not more than 5.0 to improve the drainage characteristics of the fiber fines/clay fraction.
Claim 3
Dependent Claim
19 words
The process according to claim 1 wherein the pH is maintained in the range of about 3.0 to 5.0.
Claim 4
Dependent Claim
20 words
The process according to claim 1 wherein the consistency of the fiber fines/clay concentrate is greater than 3.0% by weight.
Claim 5
Dependent Claim
19 words
The process according to claim 1 wherein the temperature is in the range of 20° C. to 90° C.
Claim 6
Dependent Claim
22 words
The process according to claim 1 wherein substantially all the fiber fines/clay fraction 5solids are able to pass a 100 mesh screen.
Claim 7
Dependent Claim
22 words
The process according to claim 1 wherein bleach is added with the acid to further improve drainage characteristics and to increase brightness.
Claim 8
Dependent Claim
21 words
The process according to claim 6 wherein said bleach is selected from the group consisting of hypochlorite, hydrosulfite, and peroxide bleaches.
Claim 9
Dependent Claim
19 words
The process according to claim 7 wherein said bleach is added in an amount less than 1% by volume.
Claim 10
Dependent Claim
24 words
The process according to claim 1 wherein the pH is raised to a neutral regime after reacting at a Ph of not more 5.
Claim 11
Dependent Claim
17 words
The process according to claim 1 wherein said separating step is carried out with a screening device.
Claim 12
Dependent Claim
28 words
The process according to claim 1 wherein said concentrating step is carried out with a device selected from the group consisting of sedimentation, flotation, and centrifugal separation equipment.
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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) | 1997-07-25 | 1998-01-24 | 1998-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-07-25 | 2002-01-24 | 2002-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-07-25 | 2006-01-24 | 2006-07-26 | $7700.00 | Window Closed / Lapsed |