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WO2007018368A1 - Procede de desencrage par flottation a rendement ameliore pour dechets de papier - Google Patents

Procede de desencrage par flottation a rendement ameliore pour dechets de papier Download PDF

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Publication number
WO2007018368A1
WO2007018368A1 PCT/KR2006/003055 KR2006003055W WO2007018368A1 WO 2007018368 A1 WO2007018368 A1 WO 2007018368A1 KR 2006003055 W KR2006003055 W KR 2006003055W WO 2007018368 A1 WO2007018368 A1 WO 2007018368A1
Authority
WO
WIPO (PCT)
Prior art keywords
paper
flotation
froth
deinking
hydrophobic
Prior art date
Application number
PCT/KR2006/003055
Other languages
English (en)
Inventor
Jeong-Yong Ryu
Yong Hwan Kim
Jae Kwang Song
Bong Keun Song
Original Assignee
Korea Research Institute Of Chemical Technology
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 Korea Research Institute Of Chemical Technology filed Critical Korea Research Institute Of Chemical Technology
Publication of WO2007018368A1 publication Critical patent/WO2007018368A1/fr

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • D21C5/02—Working-up waste paper
    • D21C5/025—De-inking
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • D21C5/005—Treatment of cellulose-containing material with microorganisms or enzymes
    • 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 relates to a method for deinking recovered(waste) paper in high yield by froth flotation. More specifically, the present invention relates to a method for deinking recovered paper in high yield by froth flotation which comprises the steps of a) concentrating hydrophobic materials and b) separating and discharging the concentrated materials wherein an esterase is added to selectively modify paper components adsorbed by hydrophobic contaminants among floating materials into hy- drophilic components.
  • [3] Korea is the eighth ranked country in the world in terms of the production and consumption of paper. 10,147,628 tons of paper and paperboard were produced in Korea in 2003. Korea has many paper companies, including related industrial fields, worth a total of ten trillion won in scale. Korean paper industry has recorded an export value of 1.6 billion US dollars in 2002 and extended from domestic markets to exports. Recycled paper produced through recycling processes accounts for 70% or more of the overall output of paper produced by Korean paper companies. The basic reason why the Korean paper industry has an environmentally friendly structure utilizing recovered paper as a major raw material is that pulp production is limited and industrial paper, which is easy to recycle, is produced in relatively large quantities in Korea. In order to ensure the continuous, sustainable development of paper industry and to promote the production of paper and paperboard in Korea in the future, sufficient supply of raw material, in particular recovered paper with keeping up of adequate quality is inevitably required.
  • recycling yield of recovered paper is usually influenced by two major factors, i.e. the amount of contaminants contained in the recovered paper and the segregation efficiency of the contaminants through cleaning treatment.
  • paper for printing e.g., newspaper, which is recycled from printed recovered paper through ink segregation processes, shows relatively low recycling yield when compared to other industrial paper.
  • Korean Patent Laid-open No. 1998-25354 discloses a method for removing ink particles from recovered paper by adding cellulase or xylanase, which are secreted from Coprinus comatus grown in a medium at pH 9, to an alkaline aqueous solution (pH 8-10) of recovered paper.
  • the weight of the ink that must be removed by froth flotation treatment is below 2% of the total weight of the recovered paper but actual rejects from the deinking method reach 10 to 14%, indicating that the method turns out to be very inefficient.
  • the reason why the froth-flotation rejects are actually discharged in larger quantities than ink printed on newspaper is that pulp fibers and inorganic fillers are also floated and discharged together with the ink.
  • the cellulose fines and fillers, to which hydrophobic contaminants are adsorbed are not contaminants, such as hydrophobic ink or sticky contaminants, to be separated by froth flotation, they are readily adsorbed to air bubbles, trapped, floated, and discharged as rejects.
  • Sizing agents that are intentionally added during production of paper for printing function to impart hydrophobicity to the surface of fibers.
  • the adsorption of sizing agents is proportional to the specific surface area of floating materials among paper components. Accordingly, sizing agents are adsorbed to cellulose fines and inorganic fillers rather than fibers, thus rendering the surfaces of the fines (cellulose fines + inorganic fillers) hydrophobic.
  • the hydrophobic fines are further hardened after collection, storage and transportation of recovered paper. Parts of the hydrophobic fines are introduced into a froth-flotation cell without being hydrated despite alkaline pulping, and discharged as rejects.
  • Froth-flotation rejects are not lost in a state in which recovered paper is collected and stored, but they are discharged after being treated in a pulper for dissociating paper, a screen for filtering contaminants and cleaning equipment (e.g., a cleaner), followed by froth flotation. Accordingly, there is the meaning that costs of water and power necessary for the treatment of the recovered paper are involved. In addition, since the froth-flotation rejects must be buried and incinerated, they cause environmental contamination.
  • the present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for deinking recovered paper in high yield by froth flotation wherein an esterase is added to modify the surfaces of cellulose fines and fillers, which are paper components other than ink, contaminated with hydrophobic additives and contaminants into hydrophilic surfaces without a loss of the cellulose fines and fillers such that the selectivity of froth flotation is improved to increase the deinking yield without a lowering in the removal efficiency of ink, thus achieving increased production efficiency of deinked recycled paper.
  • a method for deinking recovered paper in high yield by froth flotation which comprises the steps of a) concentrating hydrophobic materials and b) separating and discharging the concentrated materials wherein an esterase, acting to cleave ester bonds, is added to selectively modify paper components adsorbed by hydrophobic contaminants among floating materials into hydrophilic components.
  • the esterase is selected from lipases, cutinases, and mixed those enzymes thereof.
  • Lipases and cutinases are enzymes belonging to the esterase class. It is economically advantageous in terms of yield relative to enzyme treatment costs to add the esterase in an amount of 0.01 to 2% by weight, based on the total dry weight of recovered paper.
  • the enzyme is preferably added after step a) and prior to step b).
  • hydrophobic contaminants are functional additives or sticky contaminants
  • the paper components are cellulose fines or inorganic fillers.
  • the deinking method of the present invention hydrophobic paper components are sequentially subjected to selective enzymatic hydrolysis and froth flotation without the addition of any chemical additive. As a result, froth-flotation rejects are reduced, and the brightness and the effective residual ink concentration (ERIC) of froth-flotation accepts are maintained at the same level as those of non- treated groups.
  • the deinking method of the present invention is a new environmentally friendly method for recycling recovered paper.
  • enzymatic treatment is performed on primary froth- flotation rejects only so that the amount of an enzyme added can be reduced. Therefore, the deinking method of the present invention is highly useful in paper industry.
  • Fig. 1 shows the hydrolysis reaction of poly(vinyl acetate) (PVAc) by the action of cutinase and lipase;
  • FIG. 2 shows the hydrolysis reaction of an AKD-cellulose ester by the action of lipase
  • FIG. 3 shows the hydrolysis reaction of an ASA-cellulose ester by the action of lipase.
  • the present invention provides a method for deinking recovered paper in high yield by froth flotation which comprises the steps of a) concentrating hydrophobic materials and b) separating and discharging the concentrated materials wherein an esterase is added to selectively modify paper components adsorbed by hydrophobic contaminants among floating materials into hydrophilic components.
  • any deinking method by froth flotation can be applied so long as it can be used to recycle recovered paper. It is preferred in terms of yield that the deinking method of the present invention is applied to a method for deinking recovered paper by froth flotation which comprises the steps of a) concentrating hydrophobic materials and b) separating and discharging the concentrated materials.
  • the esterase used in the deinking method of the present invention is an enzyme acting to cleave ester bonds. More preferably, the esterase is selected from lipases, cutinases, and mixed those enzymes thereof. Lipases and cutinases are enzymes belonging to the esterase class. The hydrophobic contaminants are functional additives or sticky contaminants, and the paper components are cellulose fines or inorganic fillers.
  • the deinking method of the present invention is not a chemical method using an inorganic salt, but a novel biochemical method using lipase as a hydrolytic enzyme to cleave ester bonds of hydrophobic additives and contaminants.
  • esterases such as lipases and cutinases
  • hydrolyze ester bonds of the surface of hydrophobic floating materials i.e. functional additives (e.g., sizing agents accumulated during deinking recycling) and contaminants
  • they are suitable for the modification of the hydrophobic floating materials into hydrophilic materials.
  • the deinking method of the present invention uses lipase from Thermomyces Lanuginosus or cutinase from Magnaporthe grisea, which is a representative breakdown enzyme of the cuticle layer (Figs. 1 to 3).
  • Fig. 1 shows the mechanism of deacetylation reaction of polyvinyl acetate (PVAc), which is a sticky contaminant and a major material for a pressure-sensitive adhesive, by the action of an enzyme
  • Figs. 2 and 3 show the hydrolytic mechanisms of an alkyl ketene dimer (AKD) and an alkenyl succinic anhydride as neutral sizing agents by the action of enzymes, respectively.
  • a rosin-alum sizing agent can be treated by lipases.
  • the three sizing agents that are most generally used in the papermaking processes are hydrolyzed by lipases.
  • lipases and cutinases belonging to the esterase class are effective for the mod- ification of functional additives and hydrophobic contaminants in the recycling of recovered paper.
  • hydrophobic paper components cellulose fines + fillers
  • the concentrated hydrophobic fines as primary rejects are subjected to effective enzymatic hydrolysis in the deinking method of the present invention, unlike in conventional deinking methods in which all paper components are enzymatically treated, to effectively modify the surface of the hydrophobic paper components into hydrophilic surface without using any chemical additive.
  • lipases and cutinases do not react with ink particles containing no ester bond, they can selectively modify the hydrophobic paper components only.
  • the amount of the enzyme used in the deinking method of the present invention is substantially the same as that of an enzyme used in a general deinking method by froth flotation.
  • the enzyme is added in an amount of 0.01 to 2% by weight, based on the total dry weight of recovered paper. If the enzyme is added in an amount of less than 0.01% by weight, selective surface modification of the hydrophobic paper components is negligible. Meanwhile, if the enzyme is added in an amount exceeding 2% by weight, floating of the hydrophobic components (cellulose fines + inorganic fillers) is excessively inhibited. This inhibited floating causes poor stability of bubbles upon deinking, resulting in a lowering in the brightness of ink-free paper components and an increase in ERIC value. Moreover, the increased amount of the enzyme leads to an increase in production costs.
  • the enzyme is preferably added after step a) of concentrating hydrophobic materials and prior to step b) separating and discharging the concentrated materials.
  • primary froth-flotation rejects are ink and paper components adsorbed by contaminants. Since appreciable amounts of the primary rejects are discharged as secondary froth-flotation rejects, enzymes, such as cellulases, hemicellulases and lipases, which are used in conventional deinking methods, cannot be applied to treat the primary rejects. That is, other enzymes, except lipases and cutinases applied to improve the froth flotation yield, are added to treat the entire paper components.
  • the primary froth- flotation rejects remaining in a concentrated state are treated with an esterase (lipase or cutinase) to make the rejects hydrophilic, followed by subsequent secondary processing to reduce the amount of the final rejects. Since the deinking method of the present invention requires a reduced amount of the enzyme as compared to conventional deinking methods in which an enzyme is added in the initial stage, it is economically advantageous over the conventional deinking methods in terms of enzyme treatment costs. [39]
  • a lipase (Resinas, Novozymes) from Thermomyces Lanuginosus was added in an amount of 0.025% by weight, based on the total dry weight of recovered paper to degrade hydrophobic additives and contaminants adsorbed to the fines, and the mixture was aged in a delta type froth-flotation cell (Voith, Germany) at 45 C with stirring at 1,850 rpm for 15 minutes.
  • Buckman Laboratories which is an enzyme causing breakdown of the cuticle layer, from Magnaporthe grisea, was used in an amount of 0.2% by weight with respect to the total dry weight of recovered paper, instead of the lipase.
  • Example 1 The procedure of Example 1 was repeated, except that no enzyme was added.
  • Comparative Example 1 were measured for froth flotation yield and ash content in a muffle furnace at 400 C. Pursuant to ISO 2470:1977, the flotation accepts and rejects were molded into pads having a basis weight of 200 g/m , and the brightness and ERIC values of the pads were measured. The obtained results are shown in Table 1.
  • ERIC effective residual ink concentration
  • ink is prepared by dispersing carbon black as a pigment in a mixture of an unsaturated oil, e.g., flaxseed oil, and a synthetic resin for crosslinking, it has no ester group on its surface, which can be modified by the enzymes. Accordingly, although the enzymes are added to cleave the ester groups present on the surfaces of the hydrophobic contaminants and to modify the contaminants into hydrophilic components, there was no influence on the ink surface and no change in the separation efficiency of the ink by froth flotation.
  • the brightness of the secondary froth-flotation rejects separated in Example 1 was by 3.5% lower than that of the rejects separated in Comparative Example 1, and the ERIC value of the secondary froth-flotation rejects separated in Example 1 was by 2,000 ppm or more higher than that of the rejects separated in Comparative Example 1.
  • the selectivity of froth flotation is improved upon deinking of recovered paper such that paper components other than ink are not discharged.
  • recycling yield of the recovered paper can be improved, thus contributing to a reduction in the production costs of recycled paper.
  • environmental pollution caused during recycling of the recovered paper can be prevented. Therefore, the deinking method of the present invention is very useful in the recycling of recovered paper.

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  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Biochemistry (AREA)
  • Microbiology (AREA)
  • Paper (AREA)

Abstract

L'invention concerne un procédé de désencrage de papier récupéré à rendement élevé par flottation par mousse. Ce procédé de désencrage comprend les étapes (a) de concentration des matières hydrophobes et (b) de séparation et de décharge des matières concentrées, une estérase étant ajoutée afin de modifier sélectivement des composés de papier adsorbés par des contaminants hydrophobes parmi des matières flottantes dans des composés hydrophiles. Selon ce procédé de désencrage, des composés de papier hydrophobes sont soumis séquentiellement à une hydrolyse enzymatique sélective et à une flottation par mousse sans addition d'un quelconque additif chimique. Par conséquent, des rejets de la flottation par mousse sont moindres et le degré de blancheur et la concentration de l'encre résiduelle efficace de la flottation par mousse sont maintenus au même niveau que celui des groupes non traités. De ce fait, ce procédé de désencrage constitue un nouveau procédé écologique de recyclage du papier récupéré. Par ailleurs, selon ce procédé de désencrage, un traitement enzymatique est réalisé sur des rejets de flottation par mousse uniquement, de telle manière que la quantité de l'enzyme ajouté peut être diminué.
PCT/KR2006/003055 2005-08-05 2006-08-03 Procede de desencrage par flottation a rendement ameliore pour dechets de papier WO2007018368A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR20050071606A KR100644267B1 (ko) 2005-08-05 2005-08-05 수율을 개선한 고지의 부상부유 탈묵방법
KR10-2005-0071606 2005-08-05

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WO2007018368A1 true WO2007018368A1 (fr) 2007-02-15

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011054694A1 (fr) * 2009-10-26 2011-05-12 Basf Se Procédé de recyclage de produits de papier enduits et/ou revêtus de polymères biodégradables
WO2011100530A1 (fr) * 2010-02-12 2011-08-18 Akzo Nobel Chemicals International B.V. Procédé destiné à éliminer l'encre d'un papier

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101863331B1 (ko) 2017-03-02 2018-06-07 주식회사 지에스나노셀 폐지 탈묵 및 셀룰로오스 분리장치

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Publication number Priority date Publication date Assignee Title
JPH02160984A (ja) * 1988-12-09 1990-06-20 Novo Ind As 古紙の脱インキ方法
KR20000003300A (ko) * 1998-06-27 2000-01-15 김충섭 부상부유 및 효소처리를 이용한 골판지 고지의 재생방법
US20020059998A1 (en) * 2000-06-16 2002-05-23 Glover Daniel E. Methods to control organic contaminants in fibers

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JPH03249291A (ja) * 1990-02-22 1991-11-07 Kurita Water Ind Ltd 古紙の脱墨方法
KR920001033A (ko) * 1990-06-08 1992-01-29 김인호 리파아제를 이용한 재생 펄프의 제조방법
JPH09241985A (ja) * 1996-03-06 1997-09-16 Mitsubishi Paper Mills Ltd 古紙の再生処理方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02160984A (ja) * 1988-12-09 1990-06-20 Novo Ind As 古紙の脱インキ方法
KR20000003300A (ko) * 1998-06-27 2000-01-15 김충섭 부상부유 및 효소처리를 이용한 골판지 고지의 재생방법
US20020059998A1 (en) * 2000-06-16 2002-05-23 Glover Daniel E. Methods to control organic contaminants in fibers

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011054694A1 (fr) * 2009-10-26 2011-05-12 Basf Se Procédé de recyclage de produits de papier enduits et/ou revêtus de polymères biodégradables
CN102575423A (zh) * 2009-10-26 2012-07-11 巴斯夫欧洲公司 回收涂胶或涂覆有可生物降解聚合物的纸产品的方法
US20120276619A1 (en) * 2009-10-26 2012-11-01 Basf Se Method for recycling paper products glued and/or coated with biodegradable polymers
US8679826B2 (en) 2009-10-26 2014-03-25 Basf Se Method for recycling paper products coated with polyester polymers
WO2011100530A1 (fr) * 2010-02-12 2011-08-18 Akzo Nobel Chemicals International B.V. Procédé destiné à éliminer l'encre d'un papier
AU2011215742B2 (en) * 2010-02-12 2016-06-02 Kemira Oyj Method for removing ink from paper
US9587350B2 (en) 2010-02-12 2017-03-07 Kemira Oyj Method for removing ink from paper
KR101918638B1 (ko) 2010-02-12 2018-11-14 케미라 오와이제이 종이로부터 잉크를 제거하는 방법

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Publication number Publication date
KR100644267B1 (ko) 2006-11-10

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