DE102017110815A1 - Process for treating a fiber suspension stream - Google Patents

Abstract

The invention relates to a process for the treatment of a pulp suspension stream formed at least partly from recovered paper, in particular OCC, comprising at least one resolution and a fractionation stage (13) for forming a long fiber fraction stream (2) and a first short fiber fraction stream (3.1), the long fiber fraction stream (2) in The method according to the invention is characterized in that the first short fiber fraction stream (3.1), preferably directly, into a separation stage (14) to form a first particulate filler stream (4.1) and a second short fiber fraction stream (3.2) and that at least a portion of the first particulate filler stream (4.1) in a grinding stage (15.4) and / or at least a portion of the second short fiber fraction stream (3.2) in the grinding stage 15.4) and / or in a further grinding stage (15.3 ) is guided and ground.

Description

The invention relates to a process for the treatment of a pulp suspension stream formed at least partly from recovered paper, in particular OCC, comprising at least one resolution and a fractionation stage to form a long fiber fraction stream and a first short fiber fraction stream, wherein the long fiber fraction stream is passed into a first milling stage and ground.

The invention also relates to a device for carrying out the method.

As is known, pulp suspensions used to make a fibrous web contain not only the actual paper fibers but also a more or less large amount of fine solids. Such fine solids may be mineral fillers, called fillers for short, such as kaolins, carbonates, etc., which are generally needed for paper production. They are also mostly called ashes, as the mineral fillers are incombustible. However, they may also be fiber fragments which are e.g. arise during the grinding of fibers. These are also called fines.

In the processing of waste paper for packaging papers and cardboard, it is customary to fractionate the total pulp flow and treat the resulting fractions separately separately.

In the dissolution stage, the dissolution of the fibers and the waste paper takes place. This is followed by several process steps for the treatment of the pulp suspension until the pulp suspension meets the required property parameters and can be transferred to a machine for producing a fibrous web. In the process, these property parameters should be constant over time in order to achieve properties of the fibrous web produced in the paper machine which are as constant as possible over time, in particular their mechanical properties, in particular their strength parameters. Especially when using wastepaper-containing raw materials in the production of packaging papers, for example, when using the waste paper "Old Corrugated Container" (OCC), large variations in the composition occur. The filler contents vary particularly strongly. These in turn affect the strength and mechanical properties of the fibrous webs produced. To dampen the effects of filler fluctuations in the pulp suspension on the strengths of the fibrous web produced, these are more or less suppressed by the use of starch, both in bulk and by surface sizing. In addition, methods for discharging fillers and fines from the pulp suspension in stock preparation are known in practice. However, this is accompanied by the disadvantage of material losses.

The known solutions are on the one hand complex and on the other hand insufficient in the result.

It is therefore an object of the invention to propose an improved process for the treatment of a pulp suspension stream formed at least partially from waste paper, in particular OCC, and to reduce or even avoid the disadvantages of the known solutions.

The object is solved by features of claim 1. The invention relates to a process for treating a pulp suspension stream formed at least in part from waste paper, in particular OCC, comprising at least one dissolution and a fractionation stage to form a long fiber fraction stream and a first short fiber fraction stream, wherein the long fiber fraction stream is passed into a first milling stage and ground. It is essential to the invention that the first short fiber fraction stream, preferably directly, is passed into a separation stage to form a first particulate filler stream and a second short fiber fraction stream, and at least a portion of the first particulate filler stream enters a milling stage and / or at least a portion of the second short fiber fraction stream the grinding step and / or in a further grinding step is performed and ground.

Among other things, the quality of recovered paper is specified in CEPI's "European List of Standard Grades of Paper and Board for Recycling EN 643" (revised 2013). By Old Corrugated Container OCC, mainly in Europe, waste paper of the variety numbers 1.04.00, 1.04.01, 1.04.02, 1.05.00 and 1.05.01 shall be understood.

By this solution suspension streams are produced with improved strength potential. This has a dampening effect in the subsequent paper machine on the negative effects of fluctuations in the composition of the raw material, in particular the fluctuations in the proportion of mineral fillers from. In addition, the strengths of the fibrous web produced from the suspension streams are increased. This effect can be used, for example, for packaging papers and cardboard, For example, liners, with increased strength values and thus according to the "CEPI Container Board List" higher quality packaging paper or cardboard, such as liners to produce. This has a direct positive economic impact for the papermaker. On the other hand, it is also possible for the papermaker to produce equivalent wrapping paper or equivalent but lower basis weight paperboard. By the resulting saving of fibers manufacturing costs can be reduced.

Also in the production of fresh fiber-based papers can be saved by the inventive method by reducing the fresh fiber content used for reasons of strength manufacturing costs.

The method according to the invention can also be advantageously used in the production of kraftliner, high-performance liners, corrugated medium and flouting. Again, the mechanical properties of the fibrous webs are improved.

The grinding of the second short fiber fraction stream is preferably carried out hochfibrillierend, so that a sufficiently high number of fibrils to achieve the required strength of the fibrous web produced therefrom arises. For this purpose, HC refiner and so-called dispersers, cone refiners and double disc refiners, which are equipped with known, suitable for the fibrillating refining knurls. These can be, for example, basalt sets.

For the first milling stage for the milling of the long fiber fraction stream, cone refiners, double-disc refiner and high-consistency refiner are suitable. The long fiber fraction stream can be used directly after milling for papermaking.

The separation step for forming a first particulate filler stream and a second short fiber fraction stream from the first short fiber fraction stream may comprise a washing step. Suitable scrubbers are known oblique screens, curved screens, drum thickeners, deashing devices (for example the Voith product VarioSplit), screw presses, flotation devices, etc.

For the milling stage and the further milling stage, cone refiners, double-disc refiners and high-consistency refiner (HC refiner) are suitable.

In a practical case, the second short fiber fraction stream is passed to a separation stage to form a short fiber fraction stream and a short fiber fraction fraction stream and the short fiber fraction fraction is ground in the milling stage and / or in the further milling stage. The separation stage can be designed as a fractionation stage. For example, a classifier, such as, for example, the product "Fiber Splitter" of the Applicant, is suitable for this purpose. As a result, the proportion of the second short fiber fraction stream to be ground can be adjusted. The short fiber fraction stream can be fed directly to the paper machine.

In one possible embodiment, the proportion of the second short fiber fraction stream to be ground with the aim of minimizing the effects of fluctuations in the composition of the raw material for producing the pulp suspension stream may also be controlled or regulated

In a further possible embodiment, the short-fiber fraction fraction is ground high-fibrillating in the milling stage or the further milling stage. For this purpose, HC refiner and so-called dispersers, cone refiners and double disc refiners, which are equipped with known, suitable for the fibrillating refining knurls. These can be, for example, basalt sets.

In one possible practical embodiment, the entire first particulate filler stream is passed to the milling stage and ground together with the short fiber fraction fraction to form a particulate filler stream. The co-grinding of the first fines filler stream with the short fiber fraction fraction fibrillating milling is supported, so that the strength potential of the short fiber fraction fraction is increased and thus the mechanical properties of the fibrous web produced therefrom is improved.

Further, the first particulate filler stream may be passed to a further separation stage to form a first particulate filler sub-stream and a second particulate filler sub-stream and the second particulate filler sub-stream may be ground in the mill stage along with the short fiber fraction fraction. The further separation stage can be used as a separator such as a hydrocyclone or classifier be carried out for separation of the first fines filler stream into two partial streams with different density of the particles, preferably wherein the second fines filler partial stream having the higher average density of the particles. This also positively influences the grinding and makes it more efficient. However, it is also conceivable to carry out the further separation stage as a flow divider, wherein both partial streams have approximately the same composition.

Advantageously, the first fine material filler partial stream is subsequently fed again, that is to say after common grinding, to the short-fiber fraction fractionated fraction and to the second fine-substance filler partial stream, with the formation of a fine material filler stream. The fine material filler stream can be fed directly to the paper machine.

In a further embodiment, at least a portion, preferably the entire first fine material filler stream is fed to the milling stage and ground and the short fiber fraction fraction ground in a further milling stage is fed to the milled first particulate filler stream after the milling stage to form a fines filler stream.

In one possible practical embodiment, the second short fiber fraction stream is not ground and forms the short fiber fraction stream which can be fed directly to the paper machine. The milled first fines filler stream forms the fines filler stream.

In one possible development, the first fines filler stream is not ground and forms the fines filler stream. The milled second short fiber fraction stream forms the short fiber fraction stream.

It is also possible that the first short fiber fraction stream is fed into a milling stage and ground. Since the short fiber fraction stream also contains fillers and fines, this variant also has a positive effect on the milling result in terms of increasing the strength potential of the pulp suspension and minimizing the effects of fluctuations in the composition of the raw material for the production of pulp suspension stream.

In a further development, it is also possible to add fresh fibers and / or fillers to influence the grinding result of the first grinding stage and / or the further grinding stage and / or the grinding stage. The virgin fibers and / or fillers may differ from the virgin fibers and / or fillers contained in the pulp suspension stream.

By treating the pulp suspension stream, the fraction streams long fiber fraction stream, short fiber fraction stream, and fines filler stream are formed to feed a paper machine.

It is also possible to add to the long fiber fraction stream or short fiber fraction stream or fines filler stream additional adjuvants from the following group: fillers, highly fibrillated fibers, especially highly fibrillated short fibers, strength enhancing additives, retention aids, virgin fibers.

In a possible further development, the long fiber fraction stream and the short fiber fraction stream and the fines filler stream are mixed and fed to a headbox of a paper machine.

In a particularly advantageous case, the long fiber fraction stream and the short fiber fraction stream are mixed and fed into the outer layers of a multi-layer headbox of a paper machine and the fines filler stream is fed into the intermediate layer of the multi-layer headbox located between the outer layers.

The object is also achieved by a device according to claim 16 for carrying out the method according to claim 1.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings.

• 1 eine erste Ausführungsform des erfindungsgemäßen Verfahrens in schematischer Darstellung;
• 2 eine zweite Ausführungsform des erfindungsgemäßen Verfahrens in schematischer Darstellung;
• 3 eine dritte Ausführungsform des erfindungsgemäßen Verfahrens in schematischer Darstellung;
• 4 eine vierte Ausführungsform des erfindungsgemäßen Verfahrens in schematischer Darstellung;
• 5 eine fünfte Ausführungsform des erfindungsgemäßen Verfahrens in schematischer Darstellung;
• 6 eine Variante des erfindungsgemäßen Verfahrens hinsichtlich der Beschickung einer Papiermaschine in schematischer Darstellung;
• 7 eine weitere Variante des erfindungsgemäßen Verfahrens hinsichtlich der Beschickung einer Papiermaschine in schematischer Darstellung;

Show it

• 1 a first embodiment of the method according to the invention in a schematic representation;
• 2 a second embodiment of the method according to the invention in a schematic representation;
• 3 a third embodiment of the method according to the invention in a schematic representation;
• 4 a fourth embodiment of the method according to the invention in a schematic representation;
• 5 a fifth embodiment of the method according to the invention in a schematic representation;
• 6 a variant of the method according to the invention with regard to the loading of a paper machine in a schematic representation;
• 7 a further variant of the method according to the invention with regard to the feeding of a paper machine in a schematic representation;

In the 1 to 5 Embodiments of the method according to the invention are shown in a schematic representation. In the following, the common features of these five embodiments are described. The method is used, for example, to produce a testliner, a carton, a kraftliner, a high-performance liner, a corrugated medium or a flooding in a paper machine. In the method for treating a pulp suspension stream formed at least partially from waste paper, in particular OCC, the raw material is first of all 1 at least partially containing waste paper, in particular OCC, in one or more treatment stages 5 to a pulp suspension stream prepared by known methods. In a first step, the raw material 1 dissolved in a dissolution step and then coarsely and finely purified by conventional methods using one or more purification steps. Between these process steps, the pulp suspension is buffered in laid paper for buffering fluctuating volume flows. After these treatment stages 5 the pulp suspension becomes a fractionating stage 13 to form a long fiber fraction stream 2 and a first short fiber fraction stream 3.1 guided. While the long fiber fraction stream 2 has a high proportion of long fibers with little fillers and fines is in the short fiber fraction stream 3.1 the proportion of short fibers and fillers and fines high. The long fiber fraction stream 2 may therefore be after one or more treatment stages 6 a first milling stage 15.2 be fed and ground. The milling stage may comprise a cone refiner or a double disc refiner or a high consistency refiner or a disperser. Subsequently, the finished long fiber fraction stream is 2 a paper machine 9 for example for producing a testliner.

The short fiber fraction stream 3.1 becomes the further treatment of a separation step 14 to form a first particulate filler stream 4.1 and a second short fiber fraction stream 3.2 guided. The separation stage 14 includes a washing step. Suitable scrubbers are known inclined screens, curved screens, drum thickeners, deashing devices (for example the Voith product VarioSplit), screw presses, flotation devices, etc. The fine material filler flow 4.1 Contains a high proportion of fillers and fines, and a small proportion of short fibers. This is then in the treatment stage 8th thickened and driven over a buffer chest. The second short fiber fraction stream 3.2 will be in the treatment stage 7 thickened and dehydrated and dispersed and also passed through a chest to buffer fluctuations in the volume flow.

To characterize the properties of the long fiber fraction stream 2 directly after the fractionation stage 13 and after the first grinding step 15.2 , as well as the first short fiber fraction stream 3.1 directly after the fractionation stage 13 and the second short fiber fraction stream 3.2 and the first particulate filler stream 4.1 each directly after the separation stage 14 in the following table the relative values of the filler content (determined after ISO 1762, 2001 ) and the degree of grinding in Schopper-Riegler [° SR] (determined according to SO5267-1) and the average length "L-wt. FM "(determined after ISO 16065-2 with the FiberMaster from L & W). The relative values are based on the values of the pulp suspension before the fractionation stage 13 based. filler freeness L-wt. FM Fibrous suspension before the fraction ierstufe 100% 100% 100% Long fiber fraction stream after the fraction <70% <65% > 120% first short fiber fraction stream > 120% > 160% <90% first fines filler stream after the separation step > 200% > 200% <25% second short fiber fraction stream <20% > 120% > 115% Long fiber fraction stream after the first milling stage <70% <80% > 110%

The long fiber fraction stream 2 thus indicates the fractionation stage 13 a filler content of less than 70% and a freeness of less than 65%, and a mean fiber length greater than 120% of the corresponding values of the pulp suspension prior to the fractionation step 13 on. Similarly, the characteristic values of the other currents can be taken from the table. The treatment stages 6 . 7 . 8th are optional and the process steps carried out therein are adapted to the requirements of the method according to the invention.

The method steps and embodiments described above apply to all in the 1 to 5 shown embodiments.

According to the first embodiment according to 1 is in the second short fiber fraction stream 3.2 after the treatment stage 7 a separation step 13.3 to form a short fiber fraction fraction 3.3 and to form a short fiber fraction stream 3 intended. The separation stage 13.3 may be fractional or merely designed as a flow divider. In the first case, two fractions are produced with different proportions of short short fibers and long short fibers. For example, the short fiber fraction stream 3 the larger proportion of long short fibers and the short fiber fraction fraction 3.3 the larger proportion of short short fibers. However, it is also possible the separation stage 13.3 operate so that the short fiber fraction stream 3 the larger proportion of short short fibers and the short fiber fraction fraction 3.3 the larger proportion of long short fibers leads. As a separation step 13.3 For example, a classifier such as Applicant's "Fiber Splitter" product is suitable. Is the separation level 13.3 designed as a flow divider, so is the composition of the short fiber fraction stream 3 and the short fiber fractional fraction stream 3.3 equal. Through the separation stage 13.3 the proportion of the second short fiber fraction stream to be ground 3.2 be set. The proportion of the second short fiber fraction stream to be ground may also be controlled or controlled by known control and orator devices with the aim of minimizing the effects of fluctuations in the composition of the raw material for the production of pulp suspension stream.

In this embodiment of the invention is a grinding stage 15.4 provided in both the first particulate filler stream 4.1 after the treatment stage 8th as well as the short fiber fraction fraction 3.3 is supplied. For this grinding, milling stages with conical refiner, double-disc refiner or high-consistency refiner (HC refiner) are suitable. The fine material filler stream formed after this milling 4 and the short fiber fraction stream 3 become a paper machine for papermaking 9 continued.

The in the 2 The second embodiment shown differs from the first embodiment in that the first particulate filler stream 4.1 before the grinding stage 15.4 to another separation stage 13.4 to form a first particulate filler partial stream 4.2 and a second particulate filler sub-stream 4.3 to be led. The second particulate filler sub-stream 4.3 is in the grinding stage 15.4 together with the short fiber fraction fraction 3.3 ground. The further separation stage may serve as a separator such as a hydrocyclone or classifier for separating the first particulate filler stream 4.1 be carried out in two partial streams with different densities of the particles, wherein preferably the second fine material filler partial stream 4.3 has the higher average density of the particles. In this case, the second fines filler partial stream 4.3 a higher proportion of fillers. This also positively influences the grinding and makes it more efficient. However, it is also conceivable, the further separation stage 13.4 to perform as a flow divider, wherein both partial streams have approximately the same composition. After the common milling of the short fiber fraction fraction 3.3 and the second particulate filler sub-stream 4.3 becomes the first fines filler partial stream 4.2 forming a fines-filler stream 4 is fed again. The fine material filler stream 4 can be led directly to the paper machine.

The in the 3 The third embodiment shown differs from the first embodiment in that the short fiber fraction partial stream 3.3 not together with the first particulate filler stream 4.1 milled together, but separately in a further grinding step 15.3 ground and then the ground first particulate filler stream 4.1 forming the fines-filler stream 4 is supplied. For the milling stage 15.4 and the further milling stage 15.3 Suitable are cone refiner, double disc refiner and high-consistency refiner (HC refiner).

According to the fourth embodiment 4 becomes the entire first particulate filler stream 4.1 after the treatment stage 8th in a grinding stage 15.4 ground and then as a fine material filler stream 4 a paper machine 9 supplied for producing a fibrous web. The second short fiber fraction stream 3.2 is called short fiber fraction stream 3 a paper machine 9 supplied for producing a fibrous web. For the milling stage 15.4 Suitable are cone refiner, double disc refiner and high-consistency refiner (HC refiner).

According to the fifth embodiment 5 becomes the entire second short fiber fraction stream 3.2 after the treatment stage 7 in another milling stage 15.3 ground and then as a short fiber fraction stream 3 a paper machine 9 supplied for producing a fibrous web. The first particulate filler stream 4.1 is unground as fine material filler stream 4 a paper machine 9 supplied for producing a fibrous web. The milling of the second short fiber fraction stream 3.2 is preferably carried out hochfibrillierend, so that a sufficiently high number of fibrils to achieve the required strength of the fibrous web produced therefrom arises. For this purpose, HC refiner and so-called dispersers, cone refiners and double disc refiners, which are equipped with known, suitable for the fibrillating refining knurls. These can be, for example, basalt sets.

In all five embodiments, in order to positively influence the grinding result of the first grinding stage 15.2 and / or the further milling stage 15.3 and / or the milling stage 15.4 Fresh fibers and / or fillers are added. The virgin fibers and / or fillers may differ from the virgin fibers and / or fillers contained in the pulp suspension stream. It is also possible to add to the respective long fiber fraction stream or short fiber fraction stream or fines filler stream additional adjuvants from the following group: fillers, highly fibrillated fibers, especially highly fibrillated short fibers, strength enhancing additives, retention aids, virgin fibers.

In 6 is a variant of the method according to the invention with regard to the feeding of a paper machine 9 shown in schematic representation. The long fiber fraction stream 2 and the short fiber fraction stream 3 and the fines filler stream 4 be in a chest 12 mixed and a headbox 11 fed to a paper machine. The mixed pulp suspension is placed over the headbox 11 a shaper 10 for forming a fibrous web, for example a Linerbahn supplied.

In 7 is another variant of the method according to the invention with respect to the feed of a paper machine 9 shown in schematic representation. In this example, the long fiber fraction stream becomes 2 and the short fiber fraction stream 3 in a chest 12 mixed and separated from the fines filler stream 4 a headbox 11 fed. This is as a multi-layer casserole 11 with two outer layers and an intermediate middle layer. The one with the long fiber fraction stream 2 mixed short fiber fraction stream 3 is the outer layers and the Feinstoff- filler flow 4 is over a chest 12 supplied to the middle layer. To improve the gap strength of the fibrous web formed, the fine material filler stream can be used 4 a strength-increasing additive, for example starch, may be added. The addition may be before or after the vat 12 or in the chest or inside the headbox 11 into the middle class.

LIST OF REFERENCE NUMBERS

1

raw material

2

Long fiber fraction stream

3

Short fiber fraction stream

3.1

first short fiber fraction stream

3.2

second short fiber fraction stream

3.3

Short fiber fraction partial flow

4

Fine material filler stream

4.1

first fine material filler stream

4.2

first fines filler partial stream

4.3

second particulate filler partial flow

5

treatment stage

6

treatment stage

7

treatment stage

8th

treatment stage

9

paper machine

10

molder

11

headbox

12

vat

13

fractionation

13.3

separation stage

13.4

further separation stage

14

separation stage

15.2

first grinding stage

15.3

further milling stage

15.4

grinding stage

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• ISO 1762, 2001 [0037]
• ISO 16065-2 [0037]

Claims (16)

Process for treating a pulp suspension stream formed at least partly from waste paper, in particular OCC, comprising at least one resolution and a fractionation stage (13) to form a long fiber fraction stream (2) and a first short fiber fraction stream (3.1), the long fiber fraction stream (2) being converted into a first milling stage ( 15.2) is guided and ground, characterized in that the first short fiber fraction stream (3.1), preferably directly, in a separation stage (14) for forming a first fines filler stream (4.1) and a second short fiber fraction stream (3.2) is performed and that at least one Part of the first particulate filler stream (4.1) in a grinding stage (15.4) and / or at least a portion of the second short fiber fraction stream (3.2) in the grinding stage 15.4) and / or in a further grinding stage (15.3) is guided and ground. Method according to Claim 1 , characterized in that the second short fiber fraction stream (3.2) is passed to a separation stage (13.3) to form a short fiber fraction stream (3) and a short fiber fraction fraction stream (3.3) and that the short fiber fraction fraction stream (3.3) in the milling stage (15.4) and / or in the further grinding step (15.3) is ground. Method according to Claim 2 , characterized in that the short fiber fraction fraction (3.3) in the milling stage (15.4) or the further milling stage (15.3) is ground high fibrillating. Method according to Claim 2 or 3 , characterized in that the entire first fines filler stream (4.1) to the grinding stage (15.4) out and milled together with the short fiber fraction fraction (3.3) to form a fines filler stream (4). Method according to Claim 2 or 3 , characterized in that the first fine material filler stream (4.1) leads to a further separation stage (13.4) for forming a first fine material filler partial stream (4.2) and a second fine material filler partial stream (4.3) and the second fine material filler partial stream (4.3) in the milling stage (15.4) together with the short fiber fraction fraction (3.3) is ground. method Claim 5 , characterized in that the first fine material filler partial stream (4.2) is subsequently fed back to the short fiber fraction fractional stream (3.3) and the second fine substance filler partial stream (4.3) to form a fine material filler stream (4). method Claim 2 or 3 , characterized in that at least a portion, preferably the entire first fines filler stream (4.1) to the grinding stage (15.4) is guided and ground and that in a further grinding step (15.3) milled short fiber fraction fraction (3.3) the milled first fines filler stream (4.1) is fed after the grinding step (15.4) to form a fines filler stream (4). Method according to Claim 1 characterized in that the second short fiber fraction stream (3.2) is not ground and forms the short fiber fraction stream (3) and that the milled first particulate filler stream (4.1) forms the particulate filler stream (4). method Claim 1 characterized in that the first particulate filler stream (4.1) is not ground and forms the particulate filler stream (4) and that the ground second short fiber fraction stream (3.2) forms the short fiber fraction stream (3). Method according to one of the preceding claims, characterized in that the first short fiber fraction stream (3.1) is guided in a grinding step and ground. Method according to one of the preceding claims, characterized in that fresh fibers and / or fillers are added to influence the grinding result of the first grinding stage (15.2) and / or the further grinding stage (15.3) and / or the grinding stage (15.4). Method according to one of the preceding claims, characterized in that a long fiber fraction stream (2) and a short fiber fraction stream (3) and a fine material filler stream (4) for feeding a paper machine (9) are formed. Method according to Claim 10 , characterized in that in the long fiber fraction stream (2) or short fiber fraction stream (3) or fine material filler stream (4) additional auxiliaries from the following group to be added: fillers, highly fibrillated fibers, in particular highly-fibrillated short fibers, strength-increasing additives, retention aids, virgin fibers. Method according to one of the preceding claims, characterized in that the paper machine (9) comprises a headbox (11), and that the long fiber fraction stream (2) and the short fiber fraction stream (3) and the fine material filler stream (4) mixed and the headbox (11 ). Method according to one of the preceding claims, characterized in that the paper machine (9) comprises a multilayer headbox (11) with a middle layer arranged between at least two outer layers, and that the long fiber fraction stream (2) and the short fiber fraction stream (3) are mixed and fed into the outer layers and that the fines filler stream (4) is fed to the middle layer. Device for carrying out the method according to Claim 1 comprising a dissolution stage and a fractionation stage (13) for forming a long fiber fraction stream (2) and a first short fiber fraction stream (3.1) and a first milling stage (15.2) for milling the long fiber fraction stream (2), characterized in that a separation stage (14) for dividing the first short-fiber fraction stream (3.1) into a first fine material filler stream (4.1) and a second short fiber fraction stream (3.2), and that a milling stage (15.4) for grinding at least a portion of the first fine material filler stream (4.1) and / or a milling stage (15.4 ) and / or a further grinding stage (15.3) for grinding at least a part of the second short fiber fraction stream (3.2) is provided.

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