CA2099755A1 - Deinking process - Google Patents
Deinking processInfo
- Publication number
- CA2099755A1 CA2099755A1 CA 2099755 CA2099755A CA2099755A1 CA 2099755 A1 CA2099755 A1 CA 2099755A1 CA 2099755 CA2099755 CA 2099755 CA 2099755 A CA2099755 A CA 2099755A CA 2099755 A1 CA2099755 A1 CA 2099755A1
- Authority
- CA
- Canada
- Prior art keywords
- paper
- waste paper
- fibers
- ink particles
- pulp
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/64—Paper recycling
Landscapes
- Paper (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Deinking of recycled waste paper, including magazine and other coated papers and office waste paper, is effected by mechanical action through the application of shear forces to a slurry of water and the waste paper, causing the fibers in the waste paper to form pulp and the ink particles and other solid contaminants to be removed from the fibers and to be sized suitable for flotation separation. The ink particles and other solid contaminants are separated from the pulp fibers by flotation. The procedure provides effective deinking without the necessity for the use of chemicals.
Deinking of recycled waste paper, including magazine and other coated papers and office waste paper, is effected by mechanical action through the application of shear forces to a slurry of water and the waste paper, causing the fibers in the waste paper to form pulp and the ink particles and other solid contaminants to be removed from the fibers and to be sized suitable for flotation separation. The ink particles and other solid contaminants are separated from the pulp fibers by flotation. The procedure provides effective deinking without the necessity for the use of chemicals.
Description
~9~
E~7--109 MIS 472 TITLE OF INVENTION
DEINKING PRgCESS
FIELD OF INVENTION
The present invention relates to the recycling of waste paper and, in particular, to the deinking of paper for recycle.
BACKGROUND TO THE INVENTION
In the recycling o~ paper, it is conventional to ef~ect a d~inking step to remove printing ink from repulped fibers prior to reuse of ths cleaned fibers. In such deinking procedure, the waste paper ~or recycling is mixed with suitable chemicals, including alkali and detergent, in a pulper and, following pulping o~ the waste paper, the resulting fiber slurry or pulp is forwarded to a flotation device where the ink is separated from the fibers.
While this procedure is effective in r~moving the ink from the waste paper and in providing a pulp suitable for further processing, including incorporativn into stock for paper sheet fo~mation, the procedure requires the addition of chemicals, which are costly.
A search has been conducted in the facilities of the United States Patent and Trademark Office with respect to 2 the procedure of the invention and, as a result, the following United States patents have been located as the most relevant to the present invention:
4,215,447 4,288,319 ~,331,53~
4,347,128 4,548l673 4,~22,784 4,749,473 4,977,~43 Of these re~erences, UOS. Patent No. 4,977,943 i5 considered to be the most pertinent. This reference describes a procedure in which waste paper is processed by pulping without chemicals and removing ink and other foreign material. The ink and foreign matter are removed using air bubbles in a vapor~ uid mixing device.
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SUMMARY OF INVENTION
The present invention provides a waste paper recycling procedure in which pulping and ink removal are effected by me hanical action alone. High shear forces are applied to a slurry of water and waste paper to separate the ink from the fibers, while at the same time decreasing the size of the separated ink particles and other solid contaminants, without substantially damaging the wood fibers. The resulting slurry then is subjected t~ conventional flotation to remove the ink particles and other solid contaminants from the clean fibers.
In accordance with the present invention, there is provided a process for the deinking o~ inked paper, which comprises forming a slurry of the inked paper in water in the substantial absence of chemical additives, effecting mechanical shearing of the slurry so as to effect separation of wood fibers in the paper one from another and to remove printing ink from the surface of the fibers to form a contaminated pulp of the wood fibers containing ink particles, and effecting physical separation of the ink particles from the wood fibers to form a clean pulp.
GENERAL_DESCRIPTION OF INVENTION
The present invention relies on the application of shear forces to waste paper to remove ink from the fibers. No chemical additives are involved, thereby eliminating their cost. The procedure differs from that descri~ed in the aforementioned U.S. Patent No.
4,977,943, in that mechanical action is employed herein, while the reference relies on the action of air bubbles.
30The procedure of the present invention has particular application to magazine paper and other coated papers and office waste paper, where the ink~ tend to be hydrophobic and are susceptible to removal from the wood fibers by mechanical action as provided hereinO
35A liquid medium comprising water and khe waste paper, including newsprint, ~irst is provided~ The loading of the waste paper in the water may vary widely, .
, ., ' ' -:
.
. .: : :
. .
- :- - , : , :
- ,':' , :.':' ' , :
~997~
but generally is about 2 to about 35 w~%, preferably about 25 to 30 wt~. This liquid medium is subjected to high shear forces, so as to repulp the fibers in the waste paper so as to provide a slurry.
The high shear forces may be appl ied in any convenient mannar which is able to effect pulping of the waste paper, as well as effecting sepaxation of ink from the fibers and sizing the ink particles and other solid contaminants, such as adhesives and plastics, to a size which permits them to be readily ~loated or otherwise separated from the slurry.
One suitable manner of effecting the high shear operation is to pass the slurry of water and waste paper between closely-spaced rotating ribbed metal surfaces, similar to a pulp refiner.
It is important that the high shear operation be effected so that the ink particles and other solid contaminants removed from the wood fibers are provided with a size distribution which permits them to be separated from the pulp fibers by flotation. In this regard, we have determined that the particle size for optimum separation by flotation is from about 30 to about 150 microns.
It is also important that th~ high shear operation be effected so that the pulp fibers not be damaged or, if there is damage, it is minimal, so as to retain their optimum value for subsequent paper sheet formation.
Once the waste paper has been repulped hy the mechanical action and the ink particles and other contaminants decreased in size to be within the desired range, the resuIting slurry is forwarded to a flotation device of conventional construction, which effects separation of the hydrophobic ink particles and other solid contaminants from the wood fibers, so as to provide a clean pulp, which then may be further processed to provide a material suitable ~or incorporation into a pulp furnish for papermaking.
, .
2~75~
~ 4 --Flotation represents the preferred pxocedure of separ~tion of ~he ink and other particles ~rom the wood fibers. Other suitable procedures may be used, if desired.
EXAMPLE
A mixture comprising approximately 50~ magazine paper and 50% office waste paper was pulped for 10 minutes in water in a laboratory pulper to form a pulp of about 5 wt% consistency. The pulp was diluted with water to about 2.5 wt% consistency and subjected to a shearing action by dispersing the pulp in the laboratory pulper for 5 mins at a blade speed of 17,500 rpm, to remove the ink and other containment from the pulp fibers.
The dispersed mass then was subjected to flotation in a laboratory flotation cell, to separate ink and other contaminant, mainly clay, particles from the wood fibres.
The distribution of particles in the pulp mass before and after flotation was determinad as was the brightness of the pulpo 20The results obtained are as follows:
Brightness (ISO) Before flotation - 53.8%
After flotation - 68.3%
Visible specks after flotation - none Particle size distribution: After dispersion 54% < 40 3g% 40-100 7% 100-200 After flotation 61% ~ 10 34% 10-30 5% > 30~
As may be seen from these results, the flotation operation removed the larger hydrophobic ink particles, resulting in a much enhanced brightness after flotation.
- . .. .
- , . .
,, , . , . :
`'`, `,. ', ~, ' ,`'`' "' "' ' ,' .'", "
, ,. . . .
: ~ '' , ' , :
SUMMARY OF DISCLOSIJRE
In summary of this disclosure, the present invention provides a novel procedure to effect deinXing of recycled paper, including magazine paper and office waste paper, which does not involve the employment of chemicals, but rather mechanical action alone. The procedure is beneficial, since the cost associated with the employment of chemicals is eliminated. Modifications are possible within the scope of this invention.
. ~ . . , ~ .
, ~
E~7--109 MIS 472 TITLE OF INVENTION
DEINKING PRgCESS
FIELD OF INVENTION
The present invention relates to the recycling of waste paper and, in particular, to the deinking of paper for recycle.
BACKGROUND TO THE INVENTION
In the recycling o~ paper, it is conventional to ef~ect a d~inking step to remove printing ink from repulped fibers prior to reuse of ths cleaned fibers. In such deinking procedure, the waste paper ~or recycling is mixed with suitable chemicals, including alkali and detergent, in a pulper and, following pulping o~ the waste paper, the resulting fiber slurry or pulp is forwarded to a flotation device where the ink is separated from the fibers.
While this procedure is effective in r~moving the ink from the waste paper and in providing a pulp suitable for further processing, including incorporativn into stock for paper sheet fo~mation, the procedure requires the addition of chemicals, which are costly.
A search has been conducted in the facilities of the United States Patent and Trademark Office with respect to 2 the procedure of the invention and, as a result, the following United States patents have been located as the most relevant to the present invention:
4,215,447 4,288,319 ~,331,53~
4,347,128 4,548l673 4,~22,784 4,749,473 4,977,~43 Of these re~erences, UOS. Patent No. 4,977,943 i5 considered to be the most pertinent. This reference describes a procedure in which waste paper is processed by pulping without chemicals and removing ink and other foreign material. The ink and foreign matter are removed using air bubbles in a vapor~ uid mixing device.
',:
' ~' ..
',' , . :
.. -:`
SUMMARY OF INVENTION
The present invention provides a waste paper recycling procedure in which pulping and ink removal are effected by me hanical action alone. High shear forces are applied to a slurry of water and waste paper to separate the ink from the fibers, while at the same time decreasing the size of the separated ink particles and other solid contaminants, without substantially damaging the wood fibers. The resulting slurry then is subjected t~ conventional flotation to remove the ink particles and other solid contaminants from the clean fibers.
In accordance with the present invention, there is provided a process for the deinking o~ inked paper, which comprises forming a slurry of the inked paper in water in the substantial absence of chemical additives, effecting mechanical shearing of the slurry so as to effect separation of wood fibers in the paper one from another and to remove printing ink from the surface of the fibers to form a contaminated pulp of the wood fibers containing ink particles, and effecting physical separation of the ink particles from the wood fibers to form a clean pulp.
GENERAL_DESCRIPTION OF INVENTION
The present invention relies on the application of shear forces to waste paper to remove ink from the fibers. No chemical additives are involved, thereby eliminating their cost. The procedure differs from that descri~ed in the aforementioned U.S. Patent No.
4,977,943, in that mechanical action is employed herein, while the reference relies on the action of air bubbles.
30The procedure of the present invention has particular application to magazine paper and other coated papers and office waste paper, where the ink~ tend to be hydrophobic and are susceptible to removal from the wood fibers by mechanical action as provided hereinO
35A liquid medium comprising water and khe waste paper, including newsprint, ~irst is provided~ The loading of the waste paper in the water may vary widely, .
, ., ' ' -:
.
. .: : :
. .
- :- - , : , :
- ,':' , :.':' ' , :
~997~
but generally is about 2 to about 35 w~%, preferably about 25 to 30 wt~. This liquid medium is subjected to high shear forces, so as to repulp the fibers in the waste paper so as to provide a slurry.
The high shear forces may be appl ied in any convenient mannar which is able to effect pulping of the waste paper, as well as effecting sepaxation of ink from the fibers and sizing the ink particles and other solid contaminants, such as adhesives and plastics, to a size which permits them to be readily ~loated or otherwise separated from the slurry.
One suitable manner of effecting the high shear operation is to pass the slurry of water and waste paper between closely-spaced rotating ribbed metal surfaces, similar to a pulp refiner.
It is important that the high shear operation be effected so that the ink particles and other solid contaminants removed from the wood fibers are provided with a size distribution which permits them to be separated from the pulp fibers by flotation. In this regard, we have determined that the particle size for optimum separation by flotation is from about 30 to about 150 microns.
It is also important that th~ high shear operation be effected so that the pulp fibers not be damaged or, if there is damage, it is minimal, so as to retain their optimum value for subsequent paper sheet formation.
Once the waste paper has been repulped hy the mechanical action and the ink particles and other contaminants decreased in size to be within the desired range, the resuIting slurry is forwarded to a flotation device of conventional construction, which effects separation of the hydrophobic ink particles and other solid contaminants from the wood fibers, so as to provide a clean pulp, which then may be further processed to provide a material suitable ~or incorporation into a pulp furnish for papermaking.
, .
2~75~
~ 4 --Flotation represents the preferred pxocedure of separ~tion of ~he ink and other particles ~rom the wood fibers. Other suitable procedures may be used, if desired.
EXAMPLE
A mixture comprising approximately 50~ magazine paper and 50% office waste paper was pulped for 10 minutes in water in a laboratory pulper to form a pulp of about 5 wt% consistency. The pulp was diluted with water to about 2.5 wt% consistency and subjected to a shearing action by dispersing the pulp in the laboratory pulper for 5 mins at a blade speed of 17,500 rpm, to remove the ink and other containment from the pulp fibers.
The dispersed mass then was subjected to flotation in a laboratory flotation cell, to separate ink and other contaminant, mainly clay, particles from the wood fibres.
The distribution of particles in the pulp mass before and after flotation was determinad as was the brightness of the pulpo 20The results obtained are as follows:
Brightness (ISO) Before flotation - 53.8%
After flotation - 68.3%
Visible specks after flotation - none Particle size distribution: After dispersion 54% < 40 3g% 40-100 7% 100-200 After flotation 61% ~ 10 34% 10-30 5% > 30~
As may be seen from these results, the flotation operation removed the larger hydrophobic ink particles, resulting in a much enhanced brightness after flotation.
- . .. .
- , . .
,, , . , . :
`'`, `,. ', ~, ' ,`'`' "' "' ' ,' .'", "
, ,. . . .
: ~ '' , ' , :
SUMMARY OF DISCLOSIJRE
In summary of this disclosure, the present invention provides a novel procedure to effect deinXing of recycled paper, including magazine paper and office waste paper, which does not involve the employment of chemicals, but rather mechanical action alone. The procedure is beneficial, since the cost associated with the employment of chemicals is eliminated. Modifications are possible within the scope of this invention.
. ~ . . , ~ .
, ~
Claims (7)
1. A process for the deinking of inked paper, which comprises:
forming a slurry of said inked paper in water in the substantial absence of chemical additives, effecting mechanical shearing of said slurry so as to effect separation of wood fibers in said paper one from another and to remove printing ink from the surface of said fibers to form a contaminated pulp of said wood fibers containing ink particles, and effecting physical separation of said ink particles from said wood fibers to form a clean pulp.
forming a slurry of said inked paper in water in the substantial absence of chemical additives, effecting mechanical shearing of said slurry so as to effect separation of wood fibers in said paper one from another and to remove printing ink from the surface of said fibers to form a contaminated pulp of said wood fibers containing ink particles, and effecting physical separation of said ink particles from said wood fibers to form a clean pulp.
2. The process of claim 1 wherein said printed paper is waste paper.
3. The process of claim 2 wherein said waste paper comprises magazine paper and/or office waste paper.
4. The process of claim 2 wherein said mechanical shearing is effected by closely-spaced rotating ribbed metal surfaces.
5. The process of claim 2 wherein said mechanical slurry is effected in such manner that said ink particles and any other solid contaminants separated from said paper by said mechanical shearing are sized from about 30 to about 150 microns.
6. The process of claim 5 wherein said mechanical shearing is effected in such manner as to minimize damage to said wood fibers.
7. The process of claim 6 wherein said physical separation of said ink particles from said wood fibers is effected by flotation of said ink particles and any other solid contaminants from said contaminated pulp.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US908,078 | 1986-09-15 | ||
| US90807892A | 1992-07-06 | 1992-07-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2099755A1 true CA2099755A1 (en) | 1994-01-07 |
Family
ID=25425136
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2099755 Abandoned CA2099755A1 (en) | 1992-07-06 | 1993-06-29 | Deinking process |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2099755A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102926259A (en) * | 2012-11-01 | 2013-02-13 | 泉州华祥纸业有限公司 | Method for improving removal effect of ink in office waste paper pulp |
-
1993
- 1993-06-29 CA CA 2099755 patent/CA2099755A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102926259A (en) * | 2012-11-01 | 2013-02-13 | 泉州华祥纸业有限公司 | Method for improving removal effect of ink in office waste paper pulp |
| CN102926259B (en) * | 2012-11-01 | 2015-06-03 | 泉州华祥纸业有限公司 | Method for improving removal effect of ink in office waste paper pulp |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |