KR19980702189A - Method and apparatus for recovering raw materials from a stream of residue or collection during papermaking - Google Patents

Abstract

The present invention resides during or during the manufacture of paper P in paper mill 1 and / or material processing apparatus 2 and / or paper machine 3 and is discharged therefrom and consists of remaining or collected materials of different materials. A process for recovering raw materials from stream (R) of the present invention, wherein the stream (R) of the remaining or collected material contains at least one fiber fraction contained in the stream (R) through a sieve and black particles. It is sent to the apparatus 4 for separating one re-fraction (A). In order to recover the raw material economically, the present invention is to separate the fiber fraction through a sieve before separating the ash fraction containing black particles (A) according to the above method, and secondly to the fiber fraction according to the predetermined paper size. Is classified into three or more different fibers, preferably long fibers (LF), short fibers (KF), and / or cut fibers (BF) via a sieve system.

Description

Method and apparatus for recovering raw materials from a stream of remaining or collected material during the paper making process

In a paper mill, a material processing apparatus is produced in a paper mill disposed on top of a paper machine, in a paper mill by producing a paper raw material suitable for paper production from new paper fibers or waste paper, or from a mixture of the fibers. It is common to make paper. Depending on the quality of the final product, this paper stock consists of a mixture of fibers of a wide variety of qualities. During the material processing step there is material remaining or collected in the process water stream in the material processing apparatus and the paper machine. Among other ingredients, this residual or collected material includes large contaminants (e.g. plastic and metal parts), fibrous materials, black particles (e.g. soot and printing ink residues), and contains large amounts of kaolin, pigments, calcium carbonate and It contains a filler containing titanium dioxide. Process water streams containing residual or collected material are discharged by paper mills and are hereafter referred to as 'streams of residual or collected material' and are conveyed to a water treatment step. The filtrate thus obtained is recycled to the paper mill and the debris removed in the water treatment step must be discharged. The invention relates in particular to a stream of residual or collected material exiting the paper mill.

In the method of known German patent 40 34 054 C1, the entire remaining or collected material is transferred as a waste water stream to the remaining waste water purification apparatus and optionally subjected to a settling operation with a coagulant. Thin debris was removed from the debris collection portion of the clarifier. The remaining wastewater was mixed with thin debris to produce a precisely determined roughness. Large contaminants contained in the stream of residual or collected material were subsequently removed by sieving. The fractionated production stream was sent to a centrifugal separator with several hydrocyclones to separate the black particles. The material stream discharged from the hydrocyclone was sent to the sieving step to make fractions containing fibers and aggregates as well as pigments and fillers. In subsequent processing steps the pigment and filler were separated from each other. Finally the fibers, pigments and fillers were recycled to the material processing stage of the paper mill.

This known method has several important disadvantages. Purification and centrifugation devices with hydrocyclones are very expensive and increase the manufacturing cost. Moreover, the amount of energy required to operate the purification device, and in particular the energy required to operate the centrifuge device, is very high because relatively high pressure is applied in the hydrocyclone during operation. In addition, precise adjustment of the thin waste stream to the hydrocyclone is expensive but necessary. Because if the thin residue concentration is out of optimum roughness, the hydrocyclone no longer works or only works at low efficiency. It is apparent that this known apparatus is designed for use in the wood pulp processing industry, since the fibers obtained from the wastewater debris are essentially pulp fibers. This known apparatus is not designed for use in the industry of waste paper processing, in which the fiber fraction obtained from the remaining or collected material contains a lot of short fibers and cut fibers, so that the fiber fraction is used. This is because it is difficult and cannot be used for most paper mills.

The invention relates to a method according to the preliminary features sections of claims 1 and 2 (a method for recovering raw materials from a stream of residual or collected materials) and to an apparatus according to the preliminary features sections of claims 9 and 10 (the To recover the raw materials from the stream.

1 is a schematic view of a paper mill 1.

The paper mill 1 comprises an existing material processing apparatus 2 and a paper machine 3. According to the invention the device 4, which is arranged directly below, must be connected with the paper mill 1 and the paper machine 3. The stream R of residual or collected material discharged from the material processing apparatus 2 and the paper making machine 3 is treated in this apparatus 4 and contained in the stream R of residual or collected material. The other materials are thereby separated and at least partially recovered.

Apparatus 4 comprises three useful separation or fractionation stages 5, 6, 7, 8, and 9, where the stream R of remaining or collected material is subsequently passed through these fractionation stages. It should be understood that more or fewer separation or classification steps are possible. The number of separation or sorting steps depends on the specific situation, first depending on the desired product to be manufactured and secondly depending on the desired grade or type of these products. A sieve, in particular a vibrating sieve, is used in each of the separation or sorting steps 5-8. The mesh hole of each sieve (s) in the separation step 5 is about 1-2 mm, and the mesh hole of each sieve (s) in the sorting step 6 is 0.5-0.3 mm. The mesh hole of each sieve (s) in the sorting step 7 is 0.1 to 0.3 mm, and the mesh hole of each sieve (s) in the sorting step 8 is 0.04 to 0.1 mm. If more than one sieve is used in the separation step 9, the smallest mesh hole is about 10 μm. However, instead of using a very fine sieve to separate in the separation step 9, flotation, sedimentation and / or filtration can occur.

The method of the present invention proceeds as follows.

The paper raw material supply source G was transferred to the material processing apparatus 2 of the paper mill 1. This raw material contains waste paper, cellulose and optionally other materials. According to the requirements of each paper to be produced, the paper raw material source G is divided into the paper raw material PR and the stream R of residual or collected material in the material processing apparatus 2 and Stream R is discharged. The paper raw material PR is conveyed to the paper machine 3 and then processed to form the paper P, and discharged out of the paper mill 1 as a product as shown in the figure. The stream R of residual or collected material is conveyed from the material processing apparatus 2 to the apparatus 4. The stream R of residual or collected material is also produced in the paper machine 3 and conveyed to the apparatus 4.

It is true here that it is particularly advantageous if the entire stream R of residual or collected material is transferred to the apparatus 4 after material processing / paper production. However, it should also be understood that portions or portions of the stream R of residual or collected material may be transferred directly to the apparatus 4 without entering the overall material processing / paper manufacturing process. do. However, the illustrated arrangement has proved to be the most advantageous: the stream R of residual or collected material, as in the prior art, is not transferred to the physicochemical purification or wastewater treatment apparatus after the material processing apparatus 2 and the paper machine 3, Transferred directly to the apparatus 4. With regard to the purification, it should be noted, of course, that the purification device is located on top of the device 4 so that the purification device may operate semi- or almost inefficiently by performing or not performing its substantial function. Of course, the scope of protection of the claims includes such embodiments.

In the illustrated embodiment, a significant amount of process water is required for paper production. The method of making paper is therefore carried out wet. Thus, the stream R of residual or collected material is carried by the process water discharged from the material processing apparatus 2, and wet separation or fractionation takes place in the apparatus 4. Depending on the requirements of each, a thin material, a medium thickness material, or a thick material can be separated in the apparatus 4. This may also be described as separation in the range of low roughness, medium roughness or high roughness. When treated in a low roughness range, the content of material in the process water is 0 to 1%. When treated in the intermediate roughness range, the content of the material in the process water is 1 to 6%, and when treated in the high roughness range, the content of the material in the process water is 6 to 18%. The test results indicate that treatment in the low roughness range is particularly advantageous for the sorting and / or separation of the ash and for the removal of black particles, since each species can be easily separated.

In wet separation, the individual steps 5, 6, 7, 8 are arranged in a cascading sequence. The stream (R) of remaining or collected material is sent to the first separation stage (5), where plastics (K) and metals (M) are removed by sieving and other contaminants (eg sand particles, wood chips, etc.). Is also removed. The long fibers LF are also sieved and removed in the second sorting step 6, the short fibers SF are also sieved and removed in the third sorting step 7, and the cut fibers BF are also sorted out in the fourth sorting step ( Removed in 8). The mesh holes of the corresponding sieves of the individual sorting steps 6, 7, 8 are as described above.

Finally, the ash A is separated in the fifth sorting step 9. The ash contains black particles, such as soot and printing ink residues, and includes a filler with a large amount of kaolin along with the pigment. The ash may also additionally contain other materials such as calcium carbonate and titanium dioxide. Ash (A) may be separated into some or all of the material in the fifth step (9) or into the following filtrate. The filtrate F discharged from the fifth step 9 is directly recycled to the material processing apparatus 2. The filtrate stream is optionally at least partially adapted to match the concentration of the stream R of residual or collected material to a predetermined value (thin material) when the stream R of residual or collected material is transferred to the apparatus 4. Can be used or transferred to a paper machine.

Regardless of how wet separation proceeds in the separation or sorting steps (5, 6, 7, 8), it is also possible to further treat the product obtained during the separation. Therefore, large contaminant fractions (KM) containing, for example, plastics and metals and discharged or obtained in the separation step 5 can be separated back into plastics on the one hand and metals on the other hand, or directly discharged. . The long fibers (LF), short fibers (KF) and cut fibers (BF) obtained in the sorting steps 6, 7, 8 can be thickened and / or dried using, for example, presses. These individual types of fibers can later be recycled to the material processing apparatus 2 as part of the paper stock source G or provided for other industrial purposes. The fractionated material containing the ash (A) obtained in the fifth separation step 9 is preferably separated into the aforementioned components. Such separation may occur by flotation, screening, sedimentation, filtration and / or centrifugation.

The treatment of the stream R of material remaining or collected in the apparatus 4 need not necessarily be a wet treatment. Of course, dry separation is also possible. This dry separation is particularly advantageous when the stream R of residual or collected material is discharged in a dry state from the material processing apparatus and / or the paper machine, which is the case where the material processing and / or the paper making itself is dried. It means that it is performed. It is of course also possible to dry the stream R of residual or collected material before it is conveyed to the apparatus 4, whereby the stream R of residual or collected material is derived from the process water from the material processing apparatus or paper machine. It is applied to the separation step as an air conveying stream R of separated, remaining or collected material.

In order to dry separate in the apparatus 4, it is necessary to pulverize the stream R of residual or collected material. This process can be carried out, for example, in a suitable mill. The stream R of pulverized residual or collected material is subsequently classified and the individual materials described above and the kinds of materials described above are obtained. For example, the sorting may take place by means of an air classifier, by centrifugation or by a cyclone or by a sieve or the like. Since the separation is done in a dry state, the material KM or the various fibers LF, KF and BF do not necessarily have to go through subsequent processing. Suspension treatment and / or other forms of treatment may be used only for fraction (A).

The present invention proceeds by a completely new route. Two alternative methods are particularly advantageous when combined, which is shown in the method of claims 1 and 2 and the apparatus of claims 9 and 10. According to the invention, it was first recognized that black particles partially adhere to fibers and large contaminants with very weak adhesion. During the separation process of the fiber fraction, the black particles can be very easily separated from large contaminants and fibers in part by the alternating effect and the sieving process taking place. Therefore, it is not necessary to separate black particles by the above-mentioned expensive method as a whole. If the black particles separate when sieving the fibers, they may cause a higher whitening effect than partly obtained by centrifugation. Expensive processing equipment of the prior art for the preliminary separation of black particles is not necessary in the present invention.

According to the present invention, even if the fiber fraction contains a large amount of short fibers and chopped fibers, the fiber fraction may be divided into different types of fibers (e.g., long fibers, short fibers and / or) depending on the desired fiber size through the corresponding sieve. Chopped fibers), it can be seen that fibrous fractions can be used with little difficulty, especially in economical ways. This suggests that even in the waste fiber processing industry, recovered fibers can be recycled into the production process in a specific way, depending on the different requirements placed on the products produced. A grade or type of fiber that cannot be used by the paper mill may be provided (ie, commercially available) or provided to other industries for the manufacture of paper of the grade where the final product meets other requirements.

Important process simplification if the stream of residual or collected material from the material processing unit and / or paper machine is fed directly or immediately to the device (ie without the intervention of a purification or water treatment device) and especially without preliminary adjustment of roughness. Is achieved. Moreover, only relatively simple processing equipment is required.

In addition, the process of the present invention offers the possibility of separating large contaminant fractions containing plastics and / or metals from the stream of remaining or collected material, for example by fractionation, prior to fractionating the fiber fraction. Fiber fractions are subsequently classified to the desired type of fiber. Finally, the ash fraction can be separated by sieving. Because at least a sifting technique is used to classify or separate large contaminants and fiber types, the corresponding sieves can be separated or classified if arranged in a cascade, so that very different types of fibers can be removed during the action of gravity. It can be recovered. Therefore, the energy consumption required to produce various grades of fiber is limited to a minimum.

In addition, complete treatment of the stream of residual or collected material yields a filtrate of sufficiently high quality that no additional water treatment step is required. Filtrates with a quality that can be adjusted to meet the requirements can be recycled directly to the material processing apparatus and / or to the paper machine, and / or to the top of the residual or collected material stream, and / or to the apparatus, or to the wastewater. .

Claims (13)

A stream of residual or collected material that occurs during and during the manufacture of the paper P in the paper mill 1 and / or the material processing apparatus 2 and / or the paper machine 3 and contains a large number of different materials ( R) is sent to an apparatus 4 for separating the one or more fiber fractions contained in the stream R of the material remaining or collected through the screening operation and the ash fraction A containing the black particles and remaining or A method for recovering raw materials from a stream of collected material (R), A method according to the method of the present invention, wherein the fiber fraction is separated by sieving prior to separation of the ash fraction (A) containing black particles. A stream of residual or collected material that occurs during and during the manufacture of the paper P in the paper mill 1 and / or the material processing apparatus 2 and / or the paper machine 3 and contains a large number of different materials ( R) is sent to an apparatus 4 for separating the one or more fiber fractions contained in the stream R of the material remaining or collected through the screening operation and the ash fraction A containing the black particles and remaining or As a method for recovering raw materials from the stream R of collected material, and in particular in the method of claim 1, Depending on the desired fiber size, in each case the fractionation of the fiber fraction is classified into two or more different fibers, preferably long fibers (LF), short fibers (KF) and / or cut fibers (BF). Characterized in that the method. 3. The stream (R) of residual or collected material discharged from the material processing apparatus (2) and / or the paper machine (3) is transferred directly or immediately to the apparatus (4). , Without the purification or the intervention of the water treatment device), in particular without preliminary adjustment of illuminance. 4. A method according to any one of claims 1 to 3, wherein the fibrous fraction or large contaminant fractions containing, for example, plastics and / or metals, before the separation of the fibrous fractions or the various types of fibers, are retained or collected by specific screening operations. Separated from the stream R of material, the at least one fiber (LF, KF, BF) obtained is preferably thickened and / or dried after fractionation, and preferably the ash fraction (A) is separated by sieving, flotation, sedimentation and And / or by filtration. The pigment according to any one of the preceding claims, wherein at least the pigment, filler and black particles are separated from the ash fraction (A), preferably via flotation and / or hydrocyclone, preferably after the separation. , The filler and / or black particles are classified. The stream (R) of the residual or collected material is conveyed to the apparatus (4) in a wet state and is from 0 to 6% by weight, preferably 0 to 1, in water. And a material content of weight percent. 7. The filtrate (F) according to any one of claims 1 to 6, after separation of the ash fraction (A), the filtrate (F) of the material processing apparatus (2) and / or the paper machine (3) and / or the remaining or collected material. Characterized in that it is sent to the top of the stream (R) and / or to the apparatus (4) or waste water. 8. Process according to any one of the preceding claims, characterized in that the sifting of large contaminants and subsequent sifting of the individual kinds of fibers in the form of a waterfall. In particular in carrying out the method described above it comprises at least one separation step (6,7,8) for each fiber sieve and one re-separation step (9) for the ash fraction (A) containing black particles, the paper mill (1) and / or a stream R of residual or collected material which occurs during and during the manufacture of the paper P in the material processing apparatus 2 and / or the paper machine 3 and which contains a large number of different materials. As an apparatus (4) for recovering raw materials from Apparatus (4), characterized in that the reseparation step (9) is arranged at the bottom of the fiber sieve separation step (6,7,8). In particular in carrying out the method described above it comprises at least one separation step (6,7,8) of the fiber sieves, in the paper mill 1 and / or the material processing apparatus 2 and / or the paper machine 3 Apparatus 4, in particular the apparatus of claim 9, which recovers raw material from a stream R of residual or collected material which occurs during and during the production of paper P and which is discharged therefrom and comprises a large number of different materials. The two or more fiber sieve sorting steps, in particular the long fiber sieve sorting step (6), the short fiber sifting sorting step (7) and / or the cut fiber sifting sorting step (8) are the fiber sifting separating steps (6, 7, 8) Apparatus (4) characterized in that provided within. 11. Device according to claim 9 or 10, characterized in that the device (4) is located directly underneath the material processing device (2) and / or the paper machine (3) (i.e. without the purification or water treatment device). Device. 12. The method according to any one of claims 9 to 11, wherein the large contaminant fractionation step (5) is located at the top of the fiber segmentation steps (6, 7, and 8), and the reseparation step (9) is preferably fractionation. A device configured as a flotation, sedimentation and / or filtration separation step. A material processing apparatus 2 and a paper machine 3 and an apparatus 4 according to any one of the preceding claims, in particular performing the method of any one of the preceding claims, Paper mill (1) for recovering raw materials from stream (R), where paper raw material source (G) is transferred to material processing device (2) and paper raw material source (G) is used for paper raw material in material processing device (2). After dividing the (PR) and the stream (R) of the remaining or collected material, the paper raw material (PR) is transferred to the paper machine (3) and the stream (R) of the remaining or collected material is the material processing apparatus (2) and And / or discharged from the paper machine 3, the apparatus 4 being located at the bottom of the material processing apparatus 2 and / or the paper machine 3.