US20120118518A1 - Method for manufacturing papermaking pulp - Google Patents

Method for manufacturing papermaking pulp Download PDF

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US20120118518A1
US20120118518A1 US13/125,466 US200913125466A US2012118518A1 US 20120118518 A1 US20120118518 A1 US 20120118518A1 US 200913125466 A US200913125466 A US 200913125466A US 2012118518 A1 US2012118518 A1 US 2012118518A1
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Prior art keywords
pulp
bleaching
deacidification
composition
contacting
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US13/125,466
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Inventor
Christophe Calais
Jean-Christophe Hostachy
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ITT Manufacturing Enterprises LLC
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Arkema France SA
ITT Manufacturing Enterprises LLC
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Assigned to ARKEMA FRANCE reassignment ARKEMA FRANCE ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HOSTACHY, JEAN-CHRISTOPHE, CALAIS, CHRISTOPHE
Assigned to ARKEMA FRANCE, ITT MANUFACTURING ENTERPRISES, INC. reassignment ARKEMA FRANCE CORRECTIVE ASSIGNMENT TO CORRECT THE INADVERTENTLY OMITTED SECOND ASSIGNEE, ITT MANUFACTURING ENTERPRISES,INC. PREVIOUSLY RECORDED ON REEL 026321 FRAME 0137. ASSIGNOR(S) HEREBY CONFIRMS THE ....ARKEMA FRANCE....AND ITT MANUFACTURING ENTERPRISES,INC.... HEREINAFTER REFERRED AS THE ASSIGNEES.. Assignors: HOSTACHY, JEAN-CHRISTOPHE, CALAIS, CHRISTOPHE
Publication of US20120118518A1 publication Critical patent/US20120118518A1/en
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    • 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
    • D21B1/14—Disintegrating in mills
    • D21B1/16—Disintegrating in mills in the presence of chemical agents
    • 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
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • 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
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
    • 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
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
    • D21C9/153—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications with ozone

Definitions

  • the present invention relates to a paper pulp manufacturing process.
  • Paper pulps called “mechanical pulps” or “high-yield pulps” or “wood pulps” are obtained directly from wood by a series of mechanical (defibering and refining) treatments carried out by means of grinders and/or refiners. The pulp may then undergo a bleaching phase in one or more steps.
  • an ozone treatment during pulp refining helps to improve the quality of the pulp produced, in particular in terms of physical properties (especially the mechanical strength of the pulp) and to reduce the energy consumption of the process.
  • the ozone treatment raises particular problems, namely a reduction in the whiteness of the pulp, a subsequent bleaching difficulty, a loss of yield relative to the wood and an increase in the chemical oxygen demand of the bleaching effluents.
  • Document FR 2329794 also describes an ozone treatment.
  • the treated pulp is mixed with a lye (caustic soda) in order to stabilize the properties conferred on the pulp by the ozone treatment.
  • a lye caustic soda
  • the pulp is then stored and subsequently used directly without being bleached in order to manufacture paper.
  • a mechanical pulp ozone treatment is described in document FR 2406023.
  • the treatment is followed by a maturing step lasting less than 30 minutes, preferably less than 10 minutes, during which the ozonated pulp remains in alkaline medium, optionally being mixed with bleaching chemicals.
  • a maturing step follows the ozonation, in the presence of a lye (caustic soda) and optionally a bleaching agent (hydrogen peroxide), for the purpose of stabilizing the pulp and optionally bleaching it at the same time.
  • a lye caustic soda
  • a bleaching agent hydrogen peroxide
  • Document EP 0276608 provides an illustration of an ozone treatment method.
  • the examples in said document show that the ozone treatment causes a loss of whiteness of the pulp.
  • a first subject of the invention is a process for manufacturing a paper pulp, comprising:
  • the deacidification step is equal to or greater than 1 hour 30 minutes, preferably equal to or greater than 2 hours and ideally equal to or greater than 3 hours.
  • the pH at the end of the deacidification step is between 7 and 8.
  • the pH varies by less than 0.1 units during the last 30 minutes of the deacidification step, preferably by less than 0.05 units.
  • the alkaline agent of the deacidification composition :
  • the bleaching composition comprises a bleaching agent and at least one alkaline agent:
  • the process includes a chelation step, preferably between the deacidification step and the bleaching step, in which the deacidified pulp is brought into contact with a chelation composition comprising a chelating agent, preferably ethylenediaminetetraacetic acid or one of its sodium salts or diethylenetriaminepentaacetic acid or one of its sodium salts.
  • a chelation composition comprising a chelating agent, preferably ethylenediaminetetraacetic acid or one of its sodium salts or diethylenetriaminepentaacetic acid or one of its sodium salts.
  • 20 kg or less but preferably less than 15 kg or less and more particularly preferably 10 kg or less of alkaline agent per tonne of mechanical pulp is used during the deacidification step.
  • the loss of wood yield after the bleaching step is less than or equal to 20%, preferably less than or equal to 16%, ideally less than or equal to 13% or even less than or equal to 10%.
  • the whiteness of the pulp after the bleaching step is equal to or greater than 65%, preferably equal to or greater than 66.3%, ideally equal to or greater than 68% or even equal to or greater than 70%.
  • the process produces effluents having a chemical oxygen demand less than or equal to 210 kg per tonne of pulp, preferably less than or equal to 180 kg per tonne of pulp, or particularly preferably less than or equal to 160 kg per tonne of pulp or even less than or equal to 145 kg per tonne of pulp.
  • the mechanical pulp is an SGW, PGW, RMP, TMP, HTMP or CTMP pulp.
  • the wood is a resinous wood, a deciduous tree wood or a mixture thereof, preferably a resinous wood and more particularly preferably a pinewood or spruce wood.
  • Another subject of the invention is a paper manufacturing process, comprising the manufacture of paper pulp according to the process described above, and the use of this paper pulp for producing paper.
  • the present invention makes it possible to overcome the drawbacks of the prior art. More particularly, it provides a more effective paper pulp bleaching process having a better yield and/or using a small amount of chemicals and/or generating less effluent to be treated.
  • the acids within the fibers tend to be progressively released.
  • the nature and the duration of the deacidification according to the invention are therefore adapted so as to obtain a stable pH before the bleaching step, thereby making it possible to neutralize all the acid species and obtain better bleaching.
  • the invention also has one or more of the advantageous characteristics mentioned below:
  • FIG. 1 shows an example of the variation in pH during a deacidification step according to the invention (experimental measurement), in which the time in minutes is plotted on the x-axis and the pH is plotted on the y-axis.
  • the paper pulp manufacturing process according to the invention comprises four successive steps:
  • the pH varies by less than X units during the last 30 minutes of the deacidification step means that the absolute value of the difference between the measured pH at the end of the deacidification step and the pH measured 30 minutes before the end of the deacidification step is less than X units.
  • the “end of the deacidification step” coincides with the start of the next step.
  • the start of the next step may denote the start of the chelation step or the start of the bleaching step, but it may also denote the start of an intermediate washing step or the start of an intermediate change-of-consistency step.
  • the next step corresponds to a new action that differs from the deacidification action and comes immediately thereafter.
  • the wood refining and ozone treatment are carried out in the manner conventionally employed in the field.
  • the raw material is any kind of suitable wood, especially resinous wood, deciduous tree wood or a mixture of the two. Preferably, it is resinous wood. Examples of appropriate wood essences include pine and spruce.
  • the wood Before refining, the wood may undergo one or more preliminary treatments, for example debarking, removal of wood knots, heat treatment, pressurization, cutting into chips, shives, logs or the like.
  • preliminary treatments for example debarking, removal of wood knots, heat treatment, pressurization, cutting into chips, shives, logs or the like.
  • the refining comprises grinding (defibering) in a grinder (under a stream of water) or in a disk refiner.
  • the refining may comprise several stages. For example, after a first grinding/defibering, the product may be separated into an accepted fraction and a rejected fraction, the rejected fraction then being refined anew before being mixed with the accepted fraction. It is possible to carry out such intermediate separations several times.
  • an ozone treatment (ozonation) is carried out to make it easier to separate the wood fibers.
  • the ozone treatment therefore helps to reduce the specific energy needed to separate the fibers and to increase the mechanical properties of the paper pulp thus treated.
  • the ozone treatment is carried out according to the methods known to those skilled in the art, for example according to the methods described in the documents of the prior art mentioned in the introduction of the present application.
  • the ozone loading is typically 0.5 to 8%, preferably 1 to 4%.
  • the ozone treatment may relate to all of the pulp or only a fraction thereof, for example the rejected fraction from the separation after the first refining step.
  • the pH may be adjusted during the ozonation or before the ozonation, for example by adding an alkaline agent, especially sodium hydroxide.
  • an alkaline agent especially sodium hydroxide.
  • a mechanical pulp is obtained that may be of any of the types known to those skilled in the art, namely in particular:
  • the deacidification preferably takes place after the ozone refining/treatment, that is to say once the ozone refining/treatment has been completed. It consists in neutralizing the acid by-products generated by the action of ozone on the constituents of the wood, which acid by-products accumulate within and on the outside (immediate environment) of the wood fibers. Even if a base were to be used before or during the ozonation, the deacidification involved here is in any case useful in order to neutralize the acid species, since the acids within the fibers are released after the ozonation, and the stock tends to become ever more acid over the course of time.
  • the deacidification comprises, preferably consists of, bringing the mechanical pulp from the first step into contact with a deacidification composition.
  • the contacting operation preferably takes place by simple mixing.
  • the pH lies within a 3 to 5 pH range, depending on the ozone treatment (amount of ozone, optional addition of caustic soda before or during the ozonation).
  • the pH lies in the 6 to 12, preferably 7 to 8, range.
  • the deacidification composition is preferably an aqueous solution comprising an alkaline agent.
  • This alkaline agent may be chosen from the oxides, hydroxides, silicates and carbonates of alkali metals and alkaline-earth metals, ammonia, aqueous ammonia and mixtures thereof.
  • alkaline agent mention may be made of potassium hydroxide, sodium hydroxide, magnesium hydroxide, calcium hydroxide, sodium carbonate, sodium silicate, magnesium carbonate and mixtures thereof.
  • the alkaline agent comprises a mild base.
  • the term “mild base” is understood to mean a base that dissociates only partially in water (pKb>0) and/or has a low solubility.
  • the alkaline agent may comprise a mild base chosen from magnesium hydroxide, calcium hydroxide, sodium carbonate, sodium silicate, magnesium carbonate and mixtures thereof, preferably magnesium hydroxide.
  • the alkaline agent comprises a mild base as mentioned above in combination with another base, for example sodium (or potassium) hydroxide.
  • a mild base for example sodium (or potassium) hydroxide.
  • the deacidification composition it is preferable for the deacidification composition not to contain sodium (or potassium) hydroxide and for the alkaline agent to consist of a mild base as defined above.
  • the use of a mild base such as magnesium hydroxide minimizes the extraction and dissolution of certain oxidized constituents of the wood after the ozone action. Therefore, the loss of yield is smaller and the polluting load resulting from the extraction is reduced.
  • the amount of alkaline agent used during the deacidification step is preferably less than or equal to 20 kg, more particularly preferably less than or equal to 15 kg and ideally less than or equal to 10 kg per tonne of mechanical pulp.
  • the duration of the deacidification step is preferably greater than 1 hour, more particularly preferably greater than or equal to 1 hour 30 minutes, ideally greater than or equal to 2 hours or even greater than or equal to 3 hours, so as to optimize the positive effect of this step on the total yield, on the production of effluents and on the whiteness.
  • the deacidification step is preferably carried out at a temperature between 4 and 95° C., more particularly preferably between 25 and 85° C. and ideally between 35 and 80° C. A temperature of about 70° C. is particularly appropriate.
  • the consistency during the deacidification step is preferably between 0.5 and 10%, more particularly preferably between 1 and 5% and ideally between 2 and 3%.
  • the consistency or dryness value of the pulp corresponds to the percentage of dry matter expressed in relation to water.
  • the consistency is the ratio of the mass of pulp to the mass of stock which comprises the pulp, water and added chemical compounds. In other words, this is the mass concentration of pulp in the aqueous medium.
  • the chelation preferably takes place after the deacidification, i.e. once the deacidification step has been completed.
  • the chelation comprises, preferably consists of, bringing the mechanical pulp from the second step into contact with a chelation composition.
  • the chelation composition is preferably an aqueous solution comprising a chelating agent.
  • the chelating agent may be any chemical compound conventionally used for this purpose in the field. Preferably, it is ethylenediaminetetraacetic acid or one of its sodium salts or diethylenetriaminepentaacetic acid or one of its sodium salts.
  • the chelating agent has a particular affinity for the metal cations present in trace amounts in the paper pulp.
  • the objective of the chelation treatment is to neutralize these cations by sequestering them and removing them from the pulp by washing the latter. Implementing the chelation step helps to improve the performance of the hydrogen peroxide bleaching treatment.
  • the amount of chelating agent used in the chelation step is typically between 0.5 and 30 kg, preferably between 1 and 20 kg, more particularly preferably between 2 and 10 kg and ideally between 3 and 5 kg per tonne of mechanical pulp.
  • the duration of the chelation step is preferably equal to or greater than about 30 minutes.
  • the chelation step is preferably carried out at a temperature between 4 and 95° C., more particularly preferably between 25 and 85° C. and ideally between 35 and 80° C. A temperature of about 70° C. is particularly appropriate.
  • the consistency during the chelation step is preferably between 0.5 and 10%, more particularly preferably between 1 and 5% and ideally between 2 and 3%.
  • the chelation step may also be carried out at the same time as the deacidification (and not thereafter) in order to limit the number and volume of the equipment items necessary for implementing the process. In this case, all that is required is to bring the pulp into contact with the chelating agent at the deacidification stage, either by adding the latter separately or by including it in the deacidification composition, preferably in the amounts indicated above.
  • the bleaching is preferably carried out after the chelation (or after the deacidification if there is no chelation), i.e. once the chelation step (or the deacidification step if there is no chelation) has been completed.
  • the bleaching comprises, preferably consists of, bringing the mechanical pulp from the third step into contact with a bleaching composition.
  • the consistency during the bleaching step is preferably between 5 and 50%, more particularly preferably between 10 and 45% and ideally between 20 and 40%.
  • the bleaching rate is more rapid at high consistency (whereas the chelation rate is rapid even at low consistency).
  • the consistency of the pulp may be increased, for example by pressing it and eliminating filtrates, comprising especially chelated metals.
  • the contacting step takes place by the bleaching composition being simply mixed with the pulp.
  • the type of apparatus used for the mixing operation is adapted according to the consistency of the pulp: direct mixing by means of an injection pump if the consistency is low or moderate (less than 10%), while a mixer is used for higher consistency (up to about 40%).
  • the bleaching composition is preferably an aqueous solution comprising a bleaching agent and an alkaline agent.
  • the bleaching agent may be any chemical compound conventionally used for this purpose in the field. Preferably, it is hydrogen peroxide, but sodium hydrosulphite may also be used.
  • the alkaline agent may comprise (or consist of) a mild base as defined in the second step.
  • the alkaline agent may comprise (or consist of) a base different from a mild base as defined in the second step, for example it may comprise (or consist of) sodium (or potassium) hydroxide.
  • the alkaline agent may comprise (or consist of) a mixture of a mild base, as defined in the second step, and a base different from a mild base (for example sodium or potassium hydroxide).
  • a mild base for example sodium or potassium hydroxide.
  • a mixture of sodium hydroxide and magnesium hydroxide constitutes a preferred alkaline agent in the bleaching composition.
  • the ratio by weight of the mild base to the base different from a mild base is between 0.001 and 1000, preferably between 0.01 and 100, more particularly preferably between 0.1 and 10 and ideally between 0.2 and 5.
  • a mild base in the bleaching composition minimizes the extraction and dissolution of certain oxidized constituents of the wood after the action of the ozone.
  • the use of a mild base makes it possible to further improve the wood yield, to reduce the effluents and the consumption of chemicals or even to improve the whiteness of the pulp.
  • the ratio by weight of the mild base to the base different from a mild base generally results from a compromise between whiteness and yield.
  • the alkaline agent of the bleaching composition comprises sodium silicate.
  • Sodium silicate has the additional function of stabilizing the bleaching agent (especially hydrogen peroxide). It is also possible to provide in the bleaching composition another stabilizing agent in addition to or in place of the sodium silicate. Polyhydroxyacrylate-type compounds constitute possible stabilizing agents.
  • the amount of bleaching agent used is typically between 5 and 100 kg, preferably between 10 and 50 kg and more particularly preferably between 20 and 40 kg per tonne of mechanical pulp.
  • the amount of alkaline agent used is typically between 5 and 100 kg, preferably between 10 and 70 kg per tonne of mechanical pulp.
  • the bleaching composition may also comprise a chelating agent as defined above, especially if the chelation step is absent or has resulted in incomplete chelation.
  • the bleaching composition may be prepared separately and then brought into contact with the pulp, but it may also be prepared directly upon contact with the pulp.
  • the various compounds of the bleaching composition are added in succession directly to the pulp.
  • the duration of the bleaching step varies depending on the type of agent used.
  • this duration is typically between 10 minutes and 8 hours, preferably between 30 minutes and 6 hours and more particularly preferably between 2 hours and 4 hours.
  • the bleaching step is preferably carried out at a temperature between 4 and 95° C., more particularly preferably between 25 and 85° C. and ideally between 35 and 80° C. A temperature of about 70° C. is particularly appropriate.
  • a paper pulp that preferably has one or more of the following characteristics:
  • the whiteness of the pulp is defined according to the ISO 2470 standard.
  • the loss of wood yield of the process is defined as follows: after each step (deacidification, chelation, bleaching), a 25% fraction of the aqueous filtrate is recovered by pressing the stock. The water is evaporated by heating the filtrate at 50° C. until a dry residue of constant mass (corresponding to the residue dissolved in the filtrate and therefore lost) is obtained.
  • the loss of yield of the step in question is calculated in the following manner:
  • Loss of yield step (100/25) ⁇ (mass of residue at the end of the step)/mass of initial pulp [after the refining step].
  • the loss of yield of the process is the sum of the losses of yield observed for each of the deacidification (when implemented), chelation and bleaching steps. This loss of yield does not take into account the ozonation step.
  • the chemical oxygen demand of the effluents is defined according to the ISO 15705 standard, the measurement being carried out using a Hach DR/2000 spectrophotometer.
  • a pine pulp was prepared using the TMP process.
  • the pulp underwent an ozone treatment during the refining phase. More precisely, the reject from the primary refiner was treated with 2% ozone, the pH being adjusted by adding 5 kg of caustic soda per tonne of pulp, and then the ozone-treated reject was mixed with the accepted fraction from the secondary refiner.
  • the whiteness of the pulp after the ozone refining/treatment was 47.3%.
  • a chelation step was provided, during which the pulp was treated with 4 kg of DTPA per tonne of pulp, with a consistency of 4% and at a temperature of 70° C. and a pH of 6-7 for 1 hour.
  • the pulp After the chelation step, the pulp underwent a bleaching step, with a consistency of 20%, at a temperature of 70° C. for a time of 2 hours.
  • pulp A on the one hand and pulp B, C and D on the other, shows that the presence of the deacidification step improves the whiteness of the pulp and the wood yield of the process and reduces the COD.
  • pulp B and pulp C show that the use of magnesium hydroxide in place of sodium hydroxide during the deacidification step, with a reduction of 30% in the amount of chemical necessary, improves the wood yield of the process and reduces the COD, with only a slightly lower whiteness.
  • pulp C and pulp D shows that a reduction of about 75% in the mass of sodium hydroxide used in the bleaching step, and replacing about 41% of this sodium hydroxide with magnesium hydroxide enables the loss of yield and the COB to be reduced by 20%.
  • a pine pulp was prepared using the TMP process.
  • the pulp underwent an ozone treatment during the refining phase. More precisely, the reject from the primary refiner was treated with 2% ozone, the pH not being adjusted, and then the ozone-treated reject was mixed with the accepted fraction from the secondary refiner.
  • the whiteness of the pulp after the ozone refining/treatment was 48.3%.
  • a chelation step was provided, during which the pulp was treated with 4 kg of DTPA per tonne of pulp, with a consistency of 2-3% and at a temperature of 70° C. and a pH of 6-7 for 1 hour.
  • the pulp After the chelation step, the pulp underwent a bleaching step, with a consistency of 20%, at a temperature of 70° C. for a time of 2 hours.
  • Comparing pulp G with pulp H shows that the approximately 75% reduction in the weight of caustic soda used in the bleaching step and the replacement of about 40% of the caustic soda with magnesium hydroxide also markedly improves all the parameters of interest, namely the whiteness of the pulp, the yield and the COD.
  • a spruce pulp was prepared using the TMP process.
  • the pulp underwent an ozone treatment during the refining phase. More precisely, the reject from the primary refiner was treated with 2% ozone, the pH not being adjusted, and then the ozone-treated reject was mixed with the accepted fraction from the secondary refiner. The whiteness of the pulp after the ozone refining/treatment was 51.2%.
  • a chelation step was provided, during which the pulp was treated with 4 kg of DTPA per tonne of pulp, with a consistency of 2-3% and at a temperature of 70° C. and a pH of 6-7 for 1 hour.
  • the pulp After the chelation step, the pulp underwent a bleaching step, with a consistency of 20%, at a temperature of 70° C. and for a time of 2 hours.
  • pulp K (comparative example) the same parameters as for pulp I were used, except that there was no deacidification step and the amount of sodium hydroxide used in the bleaching composition was 37.5 kg/tonne of pulp.
  • pulp L (comparative example), the same parameters as for pulp J were used, except that the duration of the deacidification step was only 30 minutes.
  • pulp M To prepare pulp M, the same parameters as for pulp J were used, except that the duration of the deacidification step was 90 minutes.
  • Comparing pulp I or pulp K on the one hand with pulp J or pulp M on the other shows that by extending the duration of the deacidification step sufficiently to stabilize the pH it is possible to improve the final whiteness while reducing the amount of reagents used in the bleaching step.
  • the test carried out on pulp L compared with the tests on pulps J and M, demonstrate that, for the same amount of reactants, a relatively short deacidification step (lasting 30 minutes) gives a lower whiteness than a long deacidification step (lasting 90 minutes or more) for a similar loss of yield.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
US13/125,466 2008-10-24 2009-10-23 Method for manufacturing papermaking pulp Abandoned US20120118518A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR0805907 2008-10-24
FR0805907A FR2937656B1 (fr) 2008-10-24 2008-10-24 Procede de fabrication de pate a papier
PCT/IB2009/007208 WO2010046768A1 (fr) 2008-10-24 2009-10-23 Procede de fabrication de pate a papier

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US (1) US20120118518A1 (fr)
EP (1) EP2350381B1 (fr)
JP (1) JP5275472B2 (fr)
CN (1) CN102197174B (fr)
CA (1) CA2739694C (fr)
FR (1) FR2937656B1 (fr)
RU (1) RU2445413C1 (fr)
WO (1) WO2010046768A1 (fr)

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US20160130751A1 (en) * 2013-06-13 2016-05-12 L'Air Liquid Societe Anonyme pour L'Etude et Explo itation des Procedes Georges Claude Method for treating chemical pulps by treatment with ozone in the presence of magnesium ions
US9522991B2 (en) 2010-09-24 2016-12-20 Ehime Prefectural Government Cellulose solution manufacturing method, cellulose precipitate manufacturing method, cellulose saccharification method, cellulose solution, and cellulose precipitate

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CN102268842B (zh) * 2011-07-28 2013-03-13 广东工业大学 可溶性四硼酸盐作为纸张脱酸剂用于纸张脱酸的方法
CN105133408A (zh) * 2015-09-01 2015-12-09 安庆市新宜纸业有限公司 一种纸浆的生产工艺
CN113930998B (zh) * 2021-09-15 2022-09-30 华南理工大学 一种臭氧联合过氧化氢的化学机械浆生产方法

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FR2937656A1 (fr) 2010-04-30
WO2010046768A1 (fr) 2010-04-29
CA2739694C (fr) 2013-05-28
JP2012506501A (ja) 2012-03-15
RU2445413C1 (ru) 2012-03-20
EP2350381A1 (fr) 2011-08-03
CN102197174B (zh) 2013-04-24
JP5275472B2 (ja) 2013-08-28
FR2937656B1 (fr) 2010-11-19
CN102197174A (zh) 2011-09-21
CA2739694A1 (fr) 2010-04-29
EP2350381B1 (fr) 2016-08-17

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