MXPA97006216A - A process to recover raw materials from a current of ordinated residual material originated daping to the manufacture of depapel and an installation of the m - Google Patents

Abstract

The present invention relates to a process for recovering raw materials from a stream of waste or collected material, which comprises a plurality of different materials and which originate during the manufacture of paper in a paper mill and / or in a facility that processes material and / or in a paper machine and which is discharged therefrom, wherein the stream of waste or collected material is fed to a facility to separate at least a fraction of fibers contained in the waste material stream or collected by means of a sieving operation and for separating an ash fraction comprising black particles, wherein the separation of the fiber fraction by means of the screening operation is carried out, according to the process, before the separation of the particles. the ash fraction containing black particles, characterized in that the fiber fraction is classified, depending on the fiber size This is done in at least two different kinds of fiber, preferably in long fibers, short fibers and / or broken fibers, by a screening operation in each case, wherein a step of sorting by screening the fibers is provided respectively for each fibr class

Description

A PROCESS TO RECOVER RAW MATERIALS FROM ONE CURRENT OF RESIDUAL OR COLLECTED MATERIAL ORIGINATED DURING THE MANUFACTURE OF PAPER AND AN INSTALLATION OF THE SAME DESCRIPTION OF THE INVENTION This invention relates to a process according to the pre-characterization clauses of claim 1 and 2, and to an installation according to the pre-characterization clauses of claims 9 and 10. The. Papermaking in a paper mill is usually affected in such a way that a suitable paper raw material for the production of important paper is produced from waste or fresh paper fibers or from a mixture of the fibers in a processing facility. material from the paper mill, in which the plant that processes material is disposed upstream of the paper machine. Depending on the quality of the final product, this paper raw material consists of a mixture of fibers of very different qualities. The collected or residual material originates in the process water stream, both in the facility that processes material during the material processing stage, and in the paper machine. Among other constituents, this waste or collected material contains coarse contaminants such as plastic and metal parts, fibrous material, black particles such as soot and printing ink residues, and contains fillers comprising a large proportion of kaolin, pigments, calcium carbonate and • titanium dioxide. The stream of the process water which contains the waste or collected material and which is discharged by the paper mill, and which is hereinafter referred to as the stream of the waste or collected material, is usually fed to the moment a stage of water treatment. The filtrate obtained therein is then recycled to the paper mill, while the slurry removed from the water treatment stage is for disposal. The present invention relates exclusively to the stream of the material collected or residual or discharged from the paper mill. In the process which is known from DE 40 34 054 Cl, the residual or total collected material is fed as a stream of waste water to a waste water clarification facility and is subject to a settling operation, optionally with the assistance of flocculants. A light substance is separated from the slurry that is collected by the chamber of the clarification facility. The residual waste water is mixed with the light suspension in order to obtain a precisely determined consistency. The coarse contaminants contained in the stream of the residual or collected material are subsequently removed by sieving. The sieving put through the stream is fed to a centrifugation facility having a plurality of hydrocyclones to separate black particles. The stream of the material which is discharged from the hydrocyclones is then fed to a sieving stage in which fractions comprising fibers and agglomerates are produced, as well as pigments and fillers. The pigment and fillers are separated from one another in a subsequent process step. Finally, the fibers, pigments and fillers are recycled to the processing stage of the papermaking material. This known process has several significant disadvantages. The clarification facility and the centrifugation facility with its hydrocyclones are very expensive. Moreover, the energy requirement to operate the clarification facility, and particularly to operate the centrifugation facility, is very high since there is a comparatively high pressure drop in the hydrocyclones during operation. In addition, the exact adjustment of the light suspension stream fed to the hydrocyclones is first expensive and secondly essential, since if the concentration of the light suspension moves away from the optimum consistency, the hydrocyclones can not be operated greatly or can only be operated with low efficiency. This known installation is explicitly designed for use in the wood pulp processing industry, since the fibers obtained from the slurry of the waste water are essentially pulp fibers. This known installation is not designed for use in an industry which also processes waste paper, where the fraction of fiber obtained from the waste or collected material contains very short and broken fibers, which makes the use of this fraction difficult. fibers and makes it impossible for most paper mills. This invention proceeds by a completely new route. The two alternative processes, which are advantageous particularly in combination, are given in the processes of claims 1 and 2 and in the device of claims 9 and 10. With the present invention, it has first been recognized for the first time that the particles Blacks adhere only partially to fibers and coarse contaminants with adhesion forces which are very weak. During the separation of the fiber fraction, the black particles can be separated in part very easily from the coarse contaminant and the fibers, due to the turbulence effects that occur, and by means of the sieving operation. Therefore it is not necessary to separate the black particles as a whole in a expensive way, handled previously. The separation of the black particles when the fibers are screened, still partly results in a greater degree of whiteness than that achieved by the centrifugation. The technology of expensive plants of the prior art for the preliminary separation of the black particles is not necessary with the present invention. It has also been recognized according to the invention that the. Fiber fraction can be used without difficulty in a particularly economical way, even if it contains large proportions of short and broken fibers, and the fiber fraction is classified by the corresponding sieves, which depend on the desired fiber size, in classes different fibers, for example, in long fibers, short fibers and / or broken fibers. This gives the possibility, even in the waste fiber processing industry, of recycling the fibers recovered for the production operation in a manner which is very specific, which depends on the demands imposed on the product to be produced. The grades or classes of fibers which can not be used by the major paper mill can be supplied, that is, sold, to other paper mills for the manufacture of grades of paper where the final product is subject to different requirements, or to other branches of industry.

An important simplification of the process is carried out if the stream of the residual or collected material, discharged from the material processing facility and / or from the paper machine, is fed directly or immediately to the installation - that is, without inter-location of a clarification or waste treatment facility - and in particles without the presetting of the consistency. Moreover, only relatively simple plant technology is required. In addition, the process provides the possibility of first separating, by a sieving operation, a contaminant fraction, coarse which contains plastics and / or metals, for example, from the waste material stream or collected before the classification of the fraction of fiber. The fiber fraction is subsequently classified into the desired fiber classes. Finally, the separation of the ash fraction can also be effected by means of the sieving operation. Due to the use of the sieving technique, at least to separate or classify coarse contaminants and fiber classes, it is possible, if the corresponding sieves are cascaded, to perform the separation or classification and in this way to effect the recovery of many different kinds of fiber, eustancialmente under the action of the force of gravity. The energy consumption required to produce the various grades of fiber is thus restricted to a minimum. Moreover, the total treatment of the stream of the residual or collected material results in filtering of sufficiently high quality, such that an additional waste treatment step is not necessary. The filtrate, the quality of which can be bet according to the requirements, can be recycled directly to the material processing facility and / or to the paper machine, and / or to the stream of waste material or collected upstream of and / or in the installation, or to waste water. The single figure is a schematic illustration of a paper mill 1. The paper mill 1 has a material processing facility 2 and a paper mill 3. It is very essential according to the invention that an installation 4 which is arranged directly or immediately downstream is associated with the paper mill 1 and with the paper mill 3 as well. The treatment of a stream of waste or collected material R which is discharged from the material processing facility 2 and the paper making facility 3 is carried out in facility 4, and the different materials contained in the stream of the waste material or collected R are therefore separated and are at least partially recovered. The installation 4 comprises three separation or classification steps available 5, 6, 7, 8, 9, through which the stream of the residual or collected material R passes in succession. It should be understood that a large or small number of separation or classification steps is possible as well. The number of stages of separation or classification depends on the particular situation, and 'is oriented first towards the desired products to be produced and second to the desired grades or classes of these products. The sieves, particularly sieves that vibrate, are used in each of the separation or sorting steps 5 to 8. The mesh opening of the respective sieve or screens in the separation step 5 is approximately 1 to 2 mm. The mesh aperture of the respective sieve or screens in sorting step 6 is between 0.5 and 0.3 mm, and is between 0.1 mm and 0.3 mm in the sorting stage 7 and between 0.04 and 0.1 mm in the sorting step 8. If At least one screen is also used in the separation stage 9, the smallest screen opening here is approximately 10 μm. However, the flotation, sedimentation and / or filtration can also be carried out in the preparation step 9, instead of the separation using a very fine sieve.

The process according to the invention proceeds as follows: A supply of raw material feed G is fed to the facility that processes the material 2 of the paper mill 1. This raw material comprises waste paper, cellulose and optional m ' among other materials. According to the requirements imposed on the respective paper to be manufactured, the supply of paper raw material G is divided into the facility that processes the material 2 into a PR paper raw material and a stream of residual or collected material R which It is to be downloaded. The PR paper raw material is fed to the paper machine 3 and processed to form the paper P, which then leaves the paper mill as a product, as indicated in the drawing. The stream of the residual or collected material R leaves the process installation of the material 2 which is fed into the installation 4. A stream of waste or collected material R also originates in the paper machine 3, and is fed to the installation 4 At this point, it should be mentioned that it is particularly advantageous if the total stream of the residual or collected material R is fed to the etching 4 which follows the material / papermaking process. However, it is to be understood of course that any partial stream or partial amounts of the stream of residual or collected material R may be originated, which have not yet been subjected to the total paper material / manufacturing process but will contain a plurality of different materials. , can also be fed directly to the inetalación 4. However the illustrated arrangement has proved to be the most advantageous, where following the installation of the process of the material 2, and the paper machine 3, the current of the residual material or collected R is not fed to a wastewater treatment plant or physical-chemical clarification as in the prior art, but is fed directly to the facility 4. With respect to clarification, it should be mentioned that it is of course possible for a clarifying installation, be arranged upstream of installation 4, where the installation of arification does not perform its current function or which only performs it to an insufficient degree, and which is thus semi-inefficiently or substantially inefficiently operated. The scope of protection of the claims also covers, of course, the modalities such as these. In the illustrated embodiment, a considerable amount of process water is necessary for papermaking. The papermaking process is therefore carried out in "wet". Accordingly, the stream of the residual or collected material R is also carried along the process water discharged from the process plant of the material 2, and a wet separation or sorting is carried out in the installation 4. According to the respective requirements. , the separation of thin matter, medium matter or coarse material can be carried out in the installation 4; This can also be described as separation in the range of low, medium or high consistency. When the treatment is carried out in the range of low consistency, the content of material in the process water is between 0 and 1%. In the range of medium consistency is between 1 and 6%, and in the range of high consistency is between 6 and 18%. Tests have shown that it is particularly advantageous for the classification of the fibers and / or separation of the ash and for the removal of black particles and the treatment is carried out in the range of low consistency, since easy separation of the particles is possible. the individual classes. In the wet separation, the individual stages 5, 6, 7, 8 are arranged in succession in cascade. The stream of the residual or collected material R is fed first to the first separation stage 5, where K plastics and M metals are removed by sieving, as well as other contaminants such as grains of sand, clays and the like. The long fibers LF are separated by sieve in the next second stage of classification 6, the short fibers KF are eliminated by sieve in the third stage of classification 7, and the broken fibers BF are separated by sieve in the fourth stage of classification 8. The mesh openings of the screens corresponding to the individual classification stages 6, 7, 8 are given above. Finally, the ash A is separated in the fifth separation stage 9. The ash contains black particles such as soot and impregnation ink residue, and also contains filling agent with a high content of kaolin, aei as well as pigment, and can additionally contain other materials such as calcium carbonate and titanium dioxide. Ash A can be separated into some or all of the materials in the fifth stage 9 or following the latter. The filtrate F leaving the fifth stage 9 is recycled directly to the installation that processes the material 2. The filtrate stream can optionally, at least in part, be used to adjust the concentration of the waste material stream or collected R to the desired value (thin matter) when it is fed to the installation 4, or it can be fed to the paper machine. It is possible, completely irrespective of the way in which the wet separation process in the separation or classification stage 5, 6, 7, 8, carry out the additional treatment of the products obtained during the separation. In this way, for example, the coarse contaminant fraction KM which comprises plastics and metals and which is discharged or obtained from the separation step 5, may be subject to separation in plastics in one way and metals in another way, or they can be arranged directly. The long fibers LF, short fibers KF and broken fibers BF obtained in the classification steps 6, 7 and 8 can be thickened using a press and / or dryer, for example. These individual fiber types can be subsequently recycled as part of the supply of feed G of paper stock to the facility that processes the material 2 or can be supplied for another industrial purpose. The sifted material, which comprises the ash A which is obtained in the fifth separation step 9, is preferably separated in the constituents mentioned above.; This can be effected by flotation, sieving, sedimentation, filtration and / or centrifugation. It should be understood that the treatment of the stream of the residual or collected material R in the installation 4 does not necessarily have to be a wet treatment. A dry separation operation is also possible, of course. It is particularly advantageous if the stream of the residual or collected material R comes from the process installation of the material and / or the paper machine in a dry state, which means that the process of the material and / or manufacture of the paper is carried out. out in a dry state. It is possible, of course, to dry the stream of the residual or collected material R before it is fed to the installation 4, therefore it is separated from the process water from the plant that processes the material or the paper machine and is subject to separation as a stream suspended in air from the residual or collected material R. In order to allow dry separation to be carried out in the installation 4, it is necessary that the stream of the residual or collected material R be pulverized. This can be carried out in an appropriate factory, for example. The pulverized stream of the residual or collected material R is subsequently classified, in the separate materials mentioned above and the kinds of materials, are obtained. Classification can be effected, for example, via air sorter, centrifugation, or by cyclones, sieves or the like. Since the separation is carried out dry it should be understood that the KM materials or the fiber classes LF, KF and BF do not necessarily require subsequent treatment. A flotation treatment and / or another form of treatment can be used simply for fraction A.

Claims (15)

1. A process for recovering raw materials from a stream of waste or collected material, characterized in that it comprises a plurality of different materials and which originate during the manufacture of paper in a paper mill and / or in a facility that processes material and / or in a paper machine and which is discharged therefrom, wherein the stream of waste or collected material is fed to a facility to separate into at least a fraction of fibers contained in the stream of waste material or collected via an operation of sieving and to separate a fraction of ash comprising black particles, wherein the separation of the fiber fraction, via the screening operation is carried out, according to the process, before the separation of the ash fraction containing particles black, characterized because the stream of residual material collected, discharged from the facility that processes materi to and / or from the paper machine is fed directly or immediately to the installation - that is without the interposition of a water clarification or treatment facility - and in particular without the presetting of the consistency.

2. The process according to claim 1, characterized in that the fiber fraction is classified, depending on the desired fiber size, into at least two different kinds of fiber, preferably long fibers, short fibers and / or fibers broken by a fiber. sieving operation in each case.

3. A process for recovering raw materials from a stream of waste or collected material comprising a plurality of different materials and which originate during the manufacture of the paper in a paper mill and / or in a facility that processes material and / or in a paper machine and which is unloaded from loe miemos, where the stream of waste or collected material is fed to a facility to separate at least a fraction of fiber contained in the waste material stream or collected by means of an operation of sieving and separating a fraction of ash comprising black particles, wherein the separation of the fiber fraction via the screening operation is carried out, according to the process, before the separation of the ash fraction containing black particles, characterized because the fiber fraction is classified, depending on the desired fiber size, into at least two different kinds of fiber, preferably in long fibers, short fibers and / or broken fibers, by a screening operation in each case, wherein the stage of screening by fibers is provided respectively for each class of fibers.

4. The process according to claim 3, characterized in that the separation of the fiber fraction, via the screening operation is carried out, according to the process, before the separation of the ash fraction containing black particles.

5. The process according to any of the preceding claims, characterized in that a coarse contaminant fraction, which contains plastics and / or metals, for example, is separated from the stream of the residual or collected material, particularly by a screening operation, before of the separation of the fiber fraction or fiber classes, in which at least one of the fiber classes obtained is preferably thickened and / or dried after sorting, and that the separation of the fraction of. The ash is preferably effected by a sieving, flotation, sedimentation and / or filtration operation.

6. The process according to any of the preceding claims, characterized in that the pigments, fillers and black particles are at least separated from the ash fraction, preferably by a flotation operation and / or via hydrocyclones, and because the pigments, fillers and / or black particles are preferably classified after separation.

7. The process according to any of the preceding claims, characterized in that the stream of waste or collected material is fed in a wet stage to the installation and has a material content of 0 to 6% by weight in water, preferably 0 to 1% by weight.

8. The process according to any of the preceding claims, characterized in that after the separation of the ash fraction the filtrate is fed to the facility that processes the material and / or the paper machine and / or to the stream of waste or collected material upstream of and / or in the installation, or to waste water.

9. The process according to any of the preceding claims, characterized in that the screening of the coarse contaminant and the subsequent screening of the separated fiber classes are effected in cascade.

10. An installation for recovering raw materials from a stream of waste or collected material, which comprises a plurality of different materials and which originate during the manufacture of paper in a paper mill and / or in a facility that processes material and / or in a paper machine and which is discharged therefrom, wherein the installation comprises at least one fiber screening stage and an ash separation stage for a fraction of ash comprising black particles, where the ash separation stage is disposed downstream of the fiber screening stage especially for carrying out the aforementioned process, characterized in that the installation is located downstream of the installation that processes the material and / or the paper machine without the interposition of a clarification or water treatment installation.

11. The installation according to claim 10, characterized in that at least two stages of. fiber screening, particularly a long fiber screening stage, a short fiber screening stage and / or a broken fiber screening stage are provided in the fiber screening stage .

12. An installation for recovering raw materials from a stream of waste or collected material, which comprises a plurality of different materials and which originate during the manufacture of paper in a paper mill and / or in a facility that processes material and / or in a paper machine and which is discharged therefrom, wherein the installation comprises at least one step of separating by fiber screening, in particular to carry out the aforementioned process, characterized in that at least two Fiber screening stages, particularly a long fiber screening stage, a short fiber screening stage and / or a broken fiber screening stage, are provided in the screening stage of the fiber. fiber.

13. The installation according to claim 12 ,. characterized in that the ash separation stage is disposed downstream of the fiber screening stage.

14. The installation according to any of claims 10 to 13, characterized in that a screening step of coarse contaminant is provided upstream of the fiber screening stage, and that the ash separation step is preferably constructed as a separation step by sieving, flotation, sedimentation and / or filtration.

15. A paper mill, particularly for carrying out the process according to any of the preceding claims, characterized in that it has an installation that processes material and that has a paper machine, wherein a supply of paper feedstock is fed to the facility that processes material to supply raw material feed, it is divided into the facility that processes material, raw material of paper which is fed to the paper machine and into a stream of residual or collected material which is discharged from the facility that processes material and / or the paper machine and having an installation according to any of claims 10 to 14, which is placed downstream of the plant processing material and / or the paper machine.