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WO1996016222A1 - Procedes de reduction en pate et de desencrage - Google Patents

Procedes de reduction en pate et de desencrage Download PDF

Info

Publication number
WO1996016222A1
WO1996016222A1 PCT/US1995/015356 US9515356W WO9616222A1 WO 1996016222 A1 WO1996016222 A1 WO 1996016222A1 US 9515356 W US9515356 W US 9515356W WO 9616222 A1 WO9616222 A1 WO 9616222A1
Authority
WO
WIPO (PCT)
Prior art keywords
waste paper
pulping
dispersing
ink
solids
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.)
Ceased
Application number
PCT/US1995/015356
Other languages
English (en)
Inventor
Don R. Scott
William J. Fondow
Albert S. Kelly
David C. Grantz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Black Clawson Co
Original Assignee
Black Clawson Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Black Clawson Co filed Critical Black Clawson Co
Priority to EP95941475A priority Critical patent/EP0793747A4/fr
Priority to JP51708996A priority patent/JP2001500572A/ja
Priority to BR9509797A priority patent/BR9509797A/pt
Publication of WO1996016222A1 publication Critical patent/WO1996016222A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/30—Defibrating by other means
    • D21B1/34—Kneading or mixing; Pulpers
    • D21B1/345—Pulpers
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/30—Defibrating by other means
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/30—Defibrating by other means
    • D21B1/32—Defibrating by other means of waste paper
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/30—Defibrating by other means
    • D21B1/34—Kneading or mixing; Pulpers
    • D21B1/342—Mixing apparatus
    • 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

Definitions

  • the present invention pertains to methods for pulping and deinking cellulosic materials such as office waste paper.
  • Recyclable office waste paper often contains ink and laser jet print particles.
  • the latter actually exist as a multiplicity of particles or carbonized specs along the waste paper surface.
  • the former may be described as comprising a mixture of pigment or organic dye, binder and solvent.
  • the ink, including laser print particles must be removed in order to provide high quality pulp stock for production of high brightness papers .
  • deinking is accomplished with chemical additives and a plurality of mechanical process steps including the sequential steps of thickening the pulp, dispersing the ink particles in the thickened pulp in a kneading machine or the like, followed by diluting the kneaded pulp. Then the pulp is forwarded to a flotation cell where the dispersed ink particles are separated via air froth flotation or the like on the surface of the pulp slurry.
  • wet deinking or cleaning steps may be interposed between this dry shredding and the subsequent pulping of the fibers in an aqueous slurry.
  • the inventive methods pertain to the discovery that raw office waste paper of the type imprinted with ink and laser jet print can be simultaneously pulped and deinked in a high solids content, viscous aqueous mixture.
  • This step of simultaneous pulping and deinking may be carried out without any upstream pretreatment steps.
  • Raw, untreated waste paper such as office waste paper
  • a kneading or shearing action in a viscous aqueous mixture having a solids content of greater than 20 wt.% solids.
  • Use of more water in the mixture than that specified actually retards the mechanical kneading or shearing action of the waste paper as it is frictionally kneaded or sheared by the machine action and action of the high solids waste paper itself rubbing against other waste paper.
  • the high solids viscous mixture may be diluted to a concentration of about 2 to 5% solids for passage through a coarse screen having openings on the order of 0.050" to 0.125" whereby large impurities will be maintained on the screen and accordingly purged from the process stream.
  • the process stream Downstream from the coarse screen, the process stream may be further diluted to about 0.8 to 1.0% solids and forwarded to a centrifugal cleaner wherein high specific gravity impurities are separated from the pulped, process stream.
  • a centrifugal cleaner wherein high specific gravity impurities are separated from the pulped, process stream.
  • separatory devices may be employed downstream from the initial centrifugal cleaning step, ending in a final washing and thickening stage that provides a 5 to 12% solids deinked pulp stock ready for bleaching and/or feed to the paper making fourdrinier or cylinder machine.
  • Figure 1 is a schematic flow diagram illustrating a process in accordance with the invention.
  • Figure 2 is a schematic view partly in side elevation and partly in section of a preferred pulping and kneading apparatus used in the process.
  • raw, untreated office waste paper is fed to pulping and kneading station 2.
  • Water is added to result in a high solids content viscous mixture having greater than about 20 wt.% solids, preferably between about 20-80 wt.% solids.
  • the waste paper is formed into a homogenous mass of substantially discrete fibers and dispersed ink particles, the latter of which are dispersed throughout the homogenous high solids content mixture.
  • the type of device to be used as the simultaneous pulping and kneading station 2 is not critical. A variety of machines will suffice. For example, in addition to the twin screw arrangement shown, conventional ball mill, banbury, Hobart mixers and Lannoye kneader-pulpers and other mixing or kneading devices may also be mentioned.
  • the simultaneous pulping and ink (including laser jet print particles) dispersion step the important criteria are that a high solids content aqueous mixture be mechanically subjected to compression and shearing action. It is thought that the high solids content requirement improves the shearing action especially and, in contrast to the normal low solids (i.e. 5-8%) or medium solids (8-20%) dispersion or kneading processes, imparts a frictional force on the waste paper, thereby improving ink particle dispersion and particle size reduction.
  • the simultaneous pulping and dispersion step at a solids content of 20-80 wt.%. More preferably, the solids content will be 30-70 wt.% with the range most preferably being 40-60 wt.%. Preliminary data suggest that about 50% solids is optimum.
  • the presently preferred apparatus for the step of simultaneous pulping and dispersing is shown in Figure 2.
  • This is a specially designed "Hi-Con” pulper sold by Black Clawson Company, Middletown, Ohio. This pulper is described in detail in U.S. Patent 4,535,943, the disclosure of which is incorporated by reference herein.
  • the pulper includes pulping tub, generally designed 110, having a bottom wall comprising an extraction plate 112 surrounded by tapered wall portion 113 and a generally cylindrical side wall 114 extending upwardly therefrom.
  • annular accepts chamber 115 having a tapered bottom 116 and an outlet pipe 117 having a conventional control valve (not shown) .
  • An additional outlet 118 is provided for reject material too large for passage through the extraction plate 112.
  • a rotor, generally designated 120 is mounted centrally of the bottom wall for rotation about a substantially vertical axis.
  • the rotor 120 is preferably driven by an electric motor (not shown) in a manner well- known in the art and disclosed, for example, in Couture U.S. Patent No. 4,109,872, disclosure of which is incorporated herein by reference.
  • a feed screw 130 Extending upwardly from the rotor hub of the rotor 120 is a feed screw 130 which includes a core section 131 forming an upwardly tapering continuation of the rotor hub.
  • This apparatus provides necessary compressive and shearing forces on the high solids, viscous aqueous mixture so as to effectively transform raw office waste or the like into a mass of substantially discrete fibers with ink and other friable contaminants substantially uniformly dispersed throughout the fibrous mass.
  • U.S. Patent 4,993,649 Another suitable apparatus for station 2 is described in U.S. Patent 4,993,649, the disclosure of which is incorporated herein by reference.
  • This device is a twin screw device in which the screws rotate in opposite directions.
  • Each screw shaft is tapered in its diameter, and, in the preferred embodiment, the tapers are disposed in opposite directions. That is, the taper direction for one of the screws extends from left to right (large o.d. to smaller o.d.) whereas the other screw taper (large o.d. to smaller o.d.) extends from right to left.
  • the ink particles including laser jet ink particles are dispersed and reduced to size whereby about 90% or greater of the particles, after working in the device 2, have particle diameters of about 160 microns or less.
  • the high solids content pulped and dispersed ink mixture 3 is then diluted to a solids concentration of about 2 to 3% and forwarded to purge screen 4 located downstream from device 2.
  • Screen 4 has apertures that are suitably sized to remove larger debris and waste from the process stream so that the slurry can be pumped and processed further.
  • the process slurry After the process slurry is forwarded through the purge screen, it may be diluted to a solids consistency of about 1-1/2 to 2% and is then injected into a liquid cyclonic cleaner 6 of the type well known in the art in which liquids/solids separation is effected via centrifugal action with the higher specific gravity articles "the heavies" exiting at the bottom and the desired, cleaned pulped slurry leaving at the top of the device.
  • a liquid cyclonic cleaner 6 of the type well known in the art in which liquids/solids separation is effected via centrifugal action with the higher specific gravity articles "the heavies" exiting at the bottom and the desired, cleaned pulped slurry leaving at the top of the device.
  • the slurry is then fed to coarse screen 8 and fine screen 10 located downstream from liquid cyclone cleaners 6.
  • the coarse screen may for instance comprise screen openings of about .050 inches to .125 inches and the fine screen having openings of about .004 to .010 inches.
  • a wet separation step namely air froth flotation device 12.
  • This device comprises air inlet 24 which forms bubbles in the vat to aid in floating ink and other floatable contaminants to the surface of the liquid where they are separated via weir 22.
  • the separation efficacy of these machines benefits the formation of small particle sizes and from good separation of the particles from the paper fibers.
  • the slurry may then be further diluted to about
  • liquid cyclonic cleaner stations 14,16 which may comprise, respectively, "X-Clone” and “Ultra-Clone” cyclonic cleaners available from Black Clawson. These, of course, provide further cleaning, removing ink and other contaminants that may remain in the slurry.
  • the slurry exiting cyclone cleaning station 16 is forwarded to washer 18 which may, for instance, be a "D.N.T.” washer available from Black Clawson.
  • washer 18 which may, for instance, be a "D.N.T.” washer available from Black Clawson.
  • the influent slurry is usually fed to the washer at about .5% to 1.0% solids with the resulting washed paper stock 20 exiting the washer being on the order of about 9 to 12% solids.
  • the washed stock 20 is ready for paper forming operations or bleaching and/or neutralizing processes prior to paper formation.
  • the high solids content viscous mixture exiting station 2 may be diluted and then fed through a coarse screen followed by a fine screen. Then, it may be fed through a cyclonic cleaner train similar to 14,16 shown in Fig. 1, followed then by a flotation cell 12 and washer 18.
  • the office waste paper containing secondary fibers is fed to the pulping and dispersion station 2 without any need for pre-pulping whatsoever (i.e. there is no pulping station upstream from station 2) .
  • the waste paper may be fed to station 2 in the form of bales, without any pretreatment, or it may be sorted, shredded or in loose form. If desirable, chemical additives, gases, or steam may be added before or during the step of simultaneous pulping and dispersing at station 2.
  • the invention can be more generally viewed as involving simultaneous pulping and dispersion of other easily friable contaminants.
  • frriable contaminants include such items as thermoplastic coatings, varnishes, sizes, plasticizers, as well as the inks including xerographical and laser print inks as referred to above.
  • use of the simultaneous pulping and dispersion step has proven successful in transforming the waste paper into a homogenous mass of substantially discrete fibers, separating adhering particles from the fibers, and dispersing the friable particles throughout the mass so that a large majority (i.e. about 70% and greater, preferably 90% or greater) of the particles are reduced in size to about 160 microns or less in diameter.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)

Abstract

La présente invention concerne un procédé de recyclage des vieux papiers de bureau tels que ceux qui ont été imprimés à l'encre ou au laser. Le vieux papier subit simultanément une réduction en pulpe et une dispersion des particules d'encre au cours d'une opération de malaxage (2) du papier donnant une boue ou un mélange aqueux à teneur élevée en solides. Après l'opération simultanée de réduction en pâte et de dispersion, il n'y a plus besoin d'opération de dispersion complémentaire pour fabriquer du papier désencré. La boue de mélange aqueux à teneur élevée en solides est diluée et acheminée vers des dispositifs de séparation de désencrage humide tels qu'une unité de flottation par écumage (12) ou similaire. La pâte ainsi traitée subit un lavage (18) puis vient former une pâte liquide de haute qualité (20) prête à subir les opérations de blanchiment et/ou de fabrication du papier.
PCT/US1995/015356 1994-11-21 1995-11-20 Procedes de reduction en pate et de desencrage Ceased WO1996016222A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP95941475A EP0793747A4 (fr) 1994-11-21 1995-11-20 Procedes de reduction en pate et de desencrage
JP51708996A JP2001500572A (ja) 1994-11-21 1995-11-20 パルプ化及び脱インキをする方法
BR9509797A BR9509797A (pt) 1994-11-21 1995-11-20 Processos para tratar fibras secundárias incluindo papel refugado contento tinta e papel refugado que possui sobre si componentes contaminantes friáveis remover a tinta de fibras secundárias e preparar um estoque de polpa para o uso nos processos de fabricação de papel

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US34285294A 1994-11-21 1994-11-21
US08/342,852 1994-11-21

Publications (1)

Publication Number Publication Date
WO1996016222A1 true WO1996016222A1 (fr) 1996-05-30

Family

ID=23343549

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1995/015356 Ceased WO1996016222A1 (fr) 1994-11-21 1995-11-20 Procedes de reduction en pate et de desencrage

Country Status (5)

Country Link
EP (1) EP0793747A4 (fr)
JP (1) JP2001500572A (fr)
BR (1) BR9509797A (fr)
CA (1) CA2203676A1 (fr)
WO (1) WO1996016222A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0931872A1 (fr) * 1998-01-23 1999-07-28 Voith Sulzer Papiertechnik Patent GmbH Procédé pour l'enlèvement d'impurités fines d'une suspension de fibres
EP0967321A1 (fr) * 1998-06-27 1999-12-29 Korea Research Institute Of Chemical Technology Procédé pour le recyclage de boítes en carton ondulé usées en utilisant un traitement de flotation et de pétrissage

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3957572A (en) * 1973-03-19 1976-05-18 Mo Ochs Domsjo Ab Process for the manufacture of paper pulp from waste paper
US4538765A (en) * 1981-12-10 1985-09-03 Escher Wyss Gmbh Method for defiberizing waste paper in a thick stock range

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3439098A1 (de) * 1984-08-30 1986-03-13 Sulzer-Escher Wyss GmbH, 7980 Ravensburg Verfahren und anordnung zur papierstoffaufbereitung
US5302245A (en) * 1991-04-02 1994-04-12 Vps Technology Partnership Integrated wastepaper treatment process

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3957572A (en) * 1973-03-19 1976-05-18 Mo Ochs Domsjo Ab Process for the manufacture of paper pulp from waste paper
US4538765A (en) * 1981-12-10 1985-09-03 Escher Wyss Gmbh Method for defiberizing waste paper in a thick stock range

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PAPER RECYCLING, STRATEGIES, ECONOMICS AND TECHNOLOGY, Chapter 38, issued 1991, GILKEY et al., "Cold Dispersion Unit Boosts Deinking Efficiency at Japanese Tissues Mills", pp. 159-162. *
See also references of EP0793747A4 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0931872A1 (fr) * 1998-01-23 1999-07-28 Voith Sulzer Papiertechnik Patent GmbH Procédé pour l'enlèvement d'impurités fines d'une suspension de fibres
US6277239B1 (en) 1998-01-23 2001-08-21 Voith Sulzer Papiertechnik Patent Gmbh Process for removing fine impurities from a fibrous suspension
US6409880B2 (en) 1998-01-23 2002-06-25 Voith Sulzer Papiertechnik Patent Gmbh Apparatus and process for removing fine impurities from a fibrous suspension
EP0967321A1 (fr) * 1998-06-27 1999-12-29 Korea Research Institute Of Chemical Technology Procédé pour le recyclage de boítes en carton ondulé usées en utilisant un traitement de flotation et de pétrissage

Also Published As

Publication number Publication date
EP0793747A1 (fr) 1997-09-10
JP2001500572A (ja) 2001-01-16
BR9509797A (pt) 1997-09-30
EP0793747A4 (fr) 1999-05-26
CA2203676A1 (fr) 1996-05-30

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