DE2416251A1 - SELECTIVE RECOVERY OF WASTE PAPER PRODUCTS - Google Patents

Description

Dr. Hans-Heinrich Willrath d- ₆₂ Wiesbaden i. April 1974

Dr. Dieter Weber ** "*" * 1327

T ^ - 1 ΤΛ1 IVI C-CC-j. Gustav-Freytag-Straße K V / Wh

Uipl.-Fhvs. Klaus oeirrert? Λ 1 R? R 1 ® ^{l06121) 3727i0}

* »^ ' ^Υ * - ^' Telegram address: WILLPATENT

PATENT LAWYERS

Docket 5765

The Black Clawson Company, 605 Clark
Street, Middletown, Ohio 45 042, USA

Selective recovery of waste paper products

Priority: Serial No. 348 496 of

April 6, 1973 in USA

The paper industry produces large quantities of corrugated cardboard for them
Packaging, in particular for the bulk packaging of foodstuffs for use in retail sales, and also, for example, cartons for a variety of products. Corrugated cardboard usually consists of a corrugated layer with a layer of laminated cardboard on one or both sides of the corrugated layer, the double-sided cardboard being used almost universally for the manufacture of cardboard.

The corrugated core of the corrugated board usually consists of a web known as 9 point corrugated base paper, which is made of

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Postal check: Frankfurt / Main 67 63-602 Bank: Dresdner Bank AG. Wiesbaden. Account no. 276807

relatively low graded or leveled and short fiber pulp or cellulose is produced. Most commonly used Materials are a neutral sulfide semi-chemical (NSSC) pulp and a short fiber kraft pulp known as "Bogus" (Schrenzpapler, which is supposed to simulate a higher quality) is known. Often one or both of these will be Pulp used along with some waste paper stock. The on However, the liners used in corrugated cardboard are usually made from a good grade of kraft pulp, and on average they consist of of the order of 70% by weight made of conventional three-ply corrugated cardboard.

Containers made from corrugated cardboard are usually used only once and then thrown away, especially in the food industry. The corrugated cardboard bins are therefore a major source of paper waste, and the waste paper represents the Available for reuse at a waste paper mill. If corrugated cardboard in the usual way for use as waste paper stock is ground or digested, the high quality power components become the inserts and the fiber components of relatively low quality of the corrugated base paper intensive mixed, and the resulting filling or the content is no longer suitable as an interlining material. It therefore becomes common used to make lower quality products such as cardboard, filler or other types of cardboard and the Corrugated base paper. Such a degradation in the The high quality strength fiber used in the corrugated liner is economically wasteful, but so far there is none

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A practical method of recovering corrugated cardboard by removing the kraft fiber from the lower quality fibers in the Corrugated base paper could be separated.

It is therefore the object of this invention to provide an effective and economical one To create a process by which used corrugated cardboard can be separated into two fractions, one of which is itself so composed primarily of kraft fiber that it is suitable for reuse as a substitute for raw fuel pulp is. The other fraction contains the majority of the NSSC and other short fiber constituents of the corrugated base paper and is to be reused for purposes such as the production of additional corrugated base paper and cardboard of various types, suitable.

The invention is based on the knowledge that when corrugated board is initially subjected to pulping activity in water suspension becomes, the layer of corrugated base paper, which is formed from short fiber pulp, a higher degree of wettability has as the layers of laminated cardboard made of long fiber pulp, and therefore the corrugated base paper is inclined in addition, to shred oneself considerably faster than power inserts. The invention therefore proposes used corrugated cardboard subjecting the corrugating base paper to a carefully controlled pulp action which is effective to relate the corrugating base paper to an area to shred small particles, while the insert is left with much larger pieces, and then the two types to separate the pulp by sorting it through perforations where the small particles pass through the larger ones Parts mainly of the power curve are retained.

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The invention is applicable to both continuous and batch operation. The continuous Operation can be carried out in a pulper or pulper fitted with a take-off plate with relatively large take-off holes, e.g. of the order of magnitude in diameter from 2.54 to 5.08 cm (1 to 2 inches). If such a pulper is operated at a high throughput rate, the a short dwell time for the corrugated cardboard, namely in the order of 1 minute, the corrugated base paper is on the desired area with the small particles is reduced, while the force input is still in relatively large pieces is located. The withdrawn fabric is then sorted through screen perforations which are sized so that only the relatively small frayed particles, e.g., 0.317 cm (1/8 inch) in diameter, can pass through. The resulting two Fractions can then be treated separately in order to prepare them for use.

Experimentally it was found that the 0.317 cm (1/8 inch) screen perforations, as described, let through Fraction contains the main part of the NSSC and other short shredded components of the corrugated base paper, but also substantially contains more Kraft fibers than the original medium and is therefore not only suitable for reuse Production of additional corrugated base paper, but also suitable for other purposes. The one held back by the sieve Fraction has such predominantly long-fiber kraft pulp that it can be used for many purposes that

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wise require a high quality strength fiber, and it is special suitable for mixing with fuel for many purposes.

The batch operation according to the invention can be carried out by means of a pulper of similar construction with the exception that its trigger plate is provided with relatively small perforations, for example 0.317 cm (1/8 inch) in diameter. In this case, the pulper should only be operated for a brief moment, with the withdrawal starting and maintaining immediately until a substantial part, e.g. 1/3, of the original batch has been removed. The one remaining in the pulper Fraction is then unloaded or dumped separately, and both fractions can, if necessary, be used for processing the the fibers contained therein for reuse are treated.

While the invention with the primary purpose of recycling The maximum size used corrugated cardboard was developed, its principles are also based on the selective fractionation of others Mixtures of sheets of waste paper with different defibering properties applicable, e.g. the following:

1. hardwood and softwood paper sheets,

2. Separation of long fibers from short fibers in paper mixes,

3. Separation of components of high density papers from those of Low density papers,

4. Separation of the wet strength fiber from the fiber with no wet strength in paper mixes.

Further advantages, features and possible uses of the The present invention will become apparent from the following description in conjunction with the drawings. Show it 1 shows a schematic representation of a plant for carrying out the process according to the invention as a continuous one Process and

2 shows a similar view of a plant for carrying out the process according to the invention as a batch process,

In Fig. 1, the pulper 10 is preferably of the construction according to US Pat. No. 3,339,851 and has a rotor 11, which rotates over a trigger plate 12 with perforations therein which are of considerable size, namely one On the order of 2.54 to 5.1 cm (1 to 2 inches) in diameter. These perforations are associated with a Outlet chamber 13 at the bottom of the pulper, from which a discharge line 14 leads to the rest of the plant. As the waste paper usually having different amounts of solid impurities, the pulper 10 is preferably with a device 15 equipped for scrap removal, which at an outlet 16 is connected at the bottom of the pulp trough at a position radially outward from the take-off plate 12, and the Pulper is usually also provided with a cable winch 17.

During operation of the plant, the pulper 10 is continuously fed with used corrugated cardboard, as shown at 20, and the discharge through the plate 12 is carried out continuously by the pump at a sufficiently rapid speed to the dwell time of the cardboard in the pulp trough to a sufficient

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accordingly to limit a short time, which is sufficient for the desired initial dissolution or decomposition of the cardboard as well as the To effect defibration of the corrugated base paper, while the force inserts are left in as large pieces as they are through the openings or perforations in the plate 12 can be peeled off. Tests show that under normal conditions a residence time of the order of 1 minute is sufficient for the purpose according to the invention.

The sludge of the shredded corrugated base paper withdrawn from the container and the piece of force insert is made heavier by the pump 21 in a liquid cyclone 22 for removal Residues and then fed to a sorting station 23, which has one or more sieves that are used to separate the small Particles of the corrugated base paper are suitable from the larger particles of the Kraft sheet. Satisfactory for this purpose Results have been obtained using a vibrating screen with sorting or screening openings in the screen plate about 0.317 cm (1/8 inch) in diameter. The one given through the openings in the sieve or sieves 23 Fabric is sent to a series of process stations which act as a cleaning station 24, a dewatering station 25 and a bale packing station 26 are shown. The structure established at each of these stations can be any conventional one Type used for these purposes in the treatment of recovered waste paper pulp, with the sieve openings round holes, slots or other shaped openings.

Test results show that the transferred from sorting station 23 Fabric approximately 1/3% by weight of the original

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Has batch. The material too large to pass through the sorting station 23 is sent to a second pulper 30, which can be of the same construction as pulper 10 and has a similar rotor 31 and take-off plate 32 with which Except that the holes in the vent plate 32 should be relatively small, e.g., about 0.317 cm (1/8 inch) in diameter The pulper 30 does not require a scrap remover, but is preferably provided with an overflow device 33 for disposal the floating waste, such as plastic sheeting, ribbons and threads. The discharge from the device 33 is than from a pump 34 to a sorting and fiberizing station 35 shown loaded, of which the permeated stock is recycled at 36 and returned to the pulper 30, and the retained Material is discharged as waste at 37. Satisfactory results have been obtained from its use in the Station 35 of an apparatus of the type described in US Pat. No. 3,698,649.

The substance released by the pulper 30 is supplied by a pump 40 a series of cleaning, sorting, and other process stations employing any conventional means that is suitable for removing fine and high weight impurities from the fabric and for other improvement the properties of the substance in a conventional manner in preparation for its reuse. this part The system is accordingly schematically shown as a cleaning station 41, sorting station 42, dewatering station 43 and bale packing station 44 shown. Since the bale packing

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station 26 carried the pulp fraction for the greater part of the shorter Having fibers, it may be practical to increase the retention of that fraction by having the retained fines recycled from sorting station 42 to the other side of the facility as shown by line 45.

As an example of the effectiveness of the practice of the invention in a test run, it would be determined that every 100 tons of waste corrugated cardboard comprised approximately 10 tonnes of light and heavy waste, 16 tonnes of NSSC fiber and 74 tonnes of kraft fiber, and it was also found that the 'paper stock had 60 tons of fibers, which were long enough to remain on a 35-mesh screen and 17 tons Had fines suitable for passage through a 100 mesh screen. Treatment of this material after the process according to the invention, as described, resulted in the following two fractions of 100 t each of the initial one being obtained Batch:

A. A mixture of 21 tons of Kraft fiber and 9 tons of NSSC fiber that would result in a total of 18 tons on the 35 mesh screen and 7 t would pass through the 100-mesh screen.

B. A mixture of 48 t of Kraft fiber and 6 t of NSSC fiber, of which a total of 44 t was retained on the 35-mesh screen and 4 t would pass through the 100-mesh screen.

It can thus be seen that fraction A is the main part of the NSSC fiber that was originally included in the batch, but only a small portion of the Kraft fiber that was originally included was fed to the pulper, and it can also be seen that fraction B by far the greater part of the long pulp and

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contained only a fraction less than 10% fines. Fraction B accordingly has a sufficiently high quality for many uses for which recycled corrugated cardboard would be unsuitable. For example, it can be used with other substances or pulps can be blended or substituted for some fuel for products that are normally made entirely Fuel, such as cardboard. It can be used unmixed as the surface layer of cardboard insert and other multi-layer products, and their quality is such that they guarantee additional finishing process stages, such as classifying and bleaching.

Fraction A is also suitable for many purposes, in particular remember that it has a higher strength content and a higher percentage of long-fiber pulp than the original corrugated base paper. It is therefore particularly suitable for reuse in corrugated base paper, and NSSC fiber can additionally be mixed with it for any purpose. If fraction A is to be used in this way, Minimal cleaning is required as any particles of bark or bark and splinters that may be present in the Corrugated base paper are not undesirable. For other purposes it depends on the extent to which it is cleaned or another Treatment is refined, depending on the appearance that is desired for the final product.

In the plant according to FIG. 2 for batch operation, the pulper 50 has a rotor 51, a take-off plate 52, and an outlet chamber 53, a discharge line 54 and a waste material disposal

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removal device 55 similar to elements 11-15 in 1, but the perforations in the vent plate 52 should be relatively small, e.g., 0.317 cm in diameter (1/8 inch). When operating this plant, the pulper 50 is initially loaded with sufficient water to surround the pulper vessel to fill up to the normal level for conventional pulping or grinding, and while the rotor is working, the load of corrugated cardboard is added as quickly as the unlocking bindings allow. As soon as the unlocking or Grinding begins, the extraction is started to make the particles sufficiently small in size to pass through the small ones Remove holes in the vent plate 52 and add water to maintain an effectively constant level.

Extraction or withdrawal will continue when the charge equilibrium is added along with sufficient water is used to maintain the liquid level in the pulper. When the whole batch has been fed into the pulper, it is used with continued withdrawal until the level in the pulper has dropped as low as possible and about 1/3 of the load has been withdrawn is. During this time interval, water can be added at a reduced rate to avoid clogging the trigger plate to prevent, and the operation of the rotor will also continue. The withdrawn by the plate 52 Sludge is as passed through the drain line 54 and the pump 58 through a liquid cyclone 60 and a shut-off valve 61 to the storage box 62 led, and from there he is shown at 63 too

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shown fed to a process line, which have the same properties as shown in FIG. 1, starting with the cleaning station 24.

After the withdrawal of the briefly shredded material from the pulper 50 has ended, e.g. by closing the valve 61, this requires Equilibrium of the non-defibrated material which was not withdrawn from the pulper 50, a defibration essentially in the same manner as described in connection with the pulper 30 in FIG. This can be done in the pulper 50 after the short-fiber material has been drawn off Part of the load can be carried out by refilling the pulper with water and continuing the Aufschlussbzw. Grinding activity until essentially the entire sheet or sheet in the pulper is sufficient for the withdrawal by the Trigger plate 52 has been frayed. In this case the valve 61 should be a two-way valve with a connection 64, which leads to a box 65 from which the fabric at 66 can be directed to a suitable process line which is the same Properties as shown in FIG. 1 can have, starting with station 41. On the other hand, the balance of contents of the pulper 50 can be discharged through a separate outlet 70 and valve 71 to a feed line 72 and pump 73, which through a liquid cyclone 74 in communication with the storage box 65 stands. In this case the connection 66 should be from the box 65 to a second fiberizing station according to the Lead pulper 30 in FIG.

According to the invention, it can be carried out batchwise or continuously, as desired work. In any case, the application of the

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practice according to the invention, as described above, to an effective Separation of the further shredded sheet or web components from the less easily shredded sheet, even if the Mixture is as intimate as it is with corrugated cardboard. The invention thus enables efficient selective fractionation or separation of the waste paper mixes according to the relative amounts or sizes of the main components of the mix. The invention accordingly is of particular value for the selective recovery of corrugated board waste because of the large quantities of those as waste paper available materials, but is also applicable to other blends of sheets of waste paper that make up a completely have other defibrillability as specified by other blends mentioned above.

Claims (5)

- ♦ " Claims j 1 j Process for the selective recovery of fibrous constituents of waste paper products with different defibrillability properties from a mixture of such products, characterized in that the mixed products are subjected to a first disintegration or grinding activity in a water suspension so that the grinding activity of the suspension is terminated as a whole, as soon as the main part of the more easily frayed products is defibrated sufficiently for passage through sieve openings of certain small size, while the main part of the less easily frayed products has not been defibrated sufficiently for passage through the openings, that the defibrated product from the suspension is thereby selectively is withdrawn so that its passage through the sieve openings of a predetermined size is caused and then the remaining suspension is subjected to a further treatment in order to shred the paper products remaining therein. 2. The method according to claim 1, characterized in that the first grinding or opening activity is carried out at a first station, with the removal at a sorting station takes place separately from the first station, and that the suspension from the first station to the sorting station with sufficient faster speed is transported to complete the unlocking operation at the first station according to claim 1. 409843 / oaii 3. The method according to claim 1, characterized in that it is a batch process, the first breakdown activity in the First station takes place and the withdrawal takes place in that the passage of the defibrated product through the sieve openings predetermined size is effected, which an outlet means from the first station. 4. The method according to claim 1, characterized in that the waste paper products comprise essentially corrugated cardboard with at least one outer layer of a substantially smaller one Degree of friability than its corrugated layer. 5. The method according to claim 1, characterized in that at least subjecting one of the shredded products to further treatment. Α098Λ3 / 0814 Blank page