JPH0593380A - Pulper - Google Patents

Abstract

PURPOSE:To remove metal foils from a vessel made of a paper, accommodating the metal foils of aluminum, etc., by rotating an impeller in a plane parallel to a screen for allowing disaggregated pulp to pass through and discharging residual materials except the pulp. CONSTITUTION:An impeller 24 is rotated in a plane parallel to a screen 26 for allowing disaggregated pulp to pass through to stir raw materials, etc., and a reagent such as NaOH. Only pulp is allowed to pass through the screen and sent to next processes and aluminum fine tips and other residual materials are discharged through a gate valve 28.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a pulper for use in a system for reclaiming pulp from multi-layer paper containing a layer of metal foil such as aluminum.

[0002]

2. Description of the Related Art In recent years, environmental problems on a global scale such as global warming have been highlighted, and it has become an international concern to investigate the cause and take countermeasures. For example, if the amount of paper used increases as it is, the amount of dust will increase accordingly, and by incinerating it, a large amount of carbon dioxide will be emitted. This is also spurring the destruction of the natural environment.

On the other hand, in recent years, the amount of paper used has been increasing due to the popularization of office automation equipment and the development of various paper products, and it is difficult to suppress the amount of pulp used. Therefore, the recycling of used paper is drawing attention, and efforts are being made to recycle used paper into usable paper. Recycled waste paper has been used for many years. However, paper containers, such as milk cartons, use high-quality pulp, and from these, it is possible to recycle paper products for various uses.

By the way, some paper containers are made of multilayer paper having a metal layer such as aluminum foil.
A typical one of such multi-layered paper is five layers of polyethylene and aluminum foil in addition to paper. By providing a layer of aluminum foil inside the container in this way, the contents can be sealed in the same manner as canned goods, so that oxygen and light are completely shielded. Therefore, when the product is sterilized and filled in such a container, it can be stored for a long period of time. Taking advantage of these advantages, this kind of container is widely used as a container for juice, long-life milk, liquor, coffee and the like.

[0005]

However, in the case of the paper container having the aluminum foil layer as described above, the pulp has not been recycled since it contains a large amount of pulp raw material. The reason is that when pulp is regenerated in the same way as a container that does not contain aluminum foil, aluminum crushed in the process of regenerating pulp is mixed with pulp, and the finally obtained paper contains a large amount of aluminum. This is because it will not be practical.

Therefore, the treatment of such a paper container becomes a problem. In the case of such a container, even if incinerated, parts other than aluminum burn, but aluminum does not burn easily,
Forcibly raising the temperature will destroy the incinerator. Further, the method of incineration is not preferable from the viewpoint of releasing carbon dioxide. Furthermore, the method of burying in the ground was also adopted, but since aluminum is not easily decomposed in the ground,
It may lead to new environmental damage. For this reason, in Europe and the United States, there is a movement to ban the use of paper containers containing aluminum.

Therefore, if possible, it is desirable to recycle such a container, but as described above, in the conventional used paper recycling system, in the case of a paper container having a layer of aluminum foil, pulp can be recycled. could not. Pulper is one of the causes. That is, in the pulper used in the conventional used paper recycling system, when removing a metal foil such as aluminum from a multi-layered paper containing a metal foil such as aluminum, clogging occurs and the metal foil is removed. There was a problem that I could not.

The present invention has been made under the above circumstances, and an object thereof is to provide a pulper capable of removing a metal foil from a paper container containing a metal foil such as aluminum. ..

[0009]

A first aspect of the invention for achieving the above object is to provide a screen having a plurality of holes for passing disintegrated pulp inside a tank, and a plane parallel to the screen. Equipped with an impeller for stirring that rotates inside, a certain amount of multi-layered paper containing a predetermined chemical and a metal foil as a raw material is charged, and the impeller is rotated to disintegrate pulp for the certain amount of raw material. After that, only the residual plastic and metal foil other than pulp are discharged.

A second invention for achieving the above object is characterized in that, in the first invention, the interval between the impeller and the screen is set to 2 mm or less.

A third invention for achieving the above object is that in the first or second invention, the diameter of the plurality of holes provided in the screen is set within a range of 1 mm to 5 mm. It is a feature.

[0012]

According to the first aspect of the present invention, the impeller is rotated to stir the raw material and the chemicals so that the aluminum is decomposed into fine pieces of a size that does not pass through the holes of the screen, and the pulp is Disaggregate finely. Thus, aluminum strips and other debris do not pass through the screen, only pulp passes through the screen and is sent to the next step. This removes most of the aluminum. A small amount of aluminum is finely crushed by an impeller so that it can pass through the screen and is carried to the next step together with the pulp, but by lowering the percentage in the pulper, it is possible to completely remove the aluminum in the subsequent steps. Becomes

According to a second aspect of the present invention, by making the gap between the impeller and the screen very narrow, such as 2 mm or less, the strip of aluminum or the like enters the gap and causes clogging. Can be prevented.

According to a third aspect of the present invention, with the above-mentioned structure, by setting the holes of the screen to values within the above range, the disintegrated pulp can easily pass through, and moreover, it becomes difficult for fine particles such as aluminum to pass through. You can

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a flow of a process of regenerating pulp from a used paper container or processing waste by a pulp regenerating system using a pulper which is one embodiment of the present invention, and FIG. 2 is a raw material in this embodiment. FIG. 3 is a schematic sectional view of a pulper which is an embodiment of the present invention, FIG. 4 is an enlarged sectional view of the impeller and the vicinity of the screen shown in FIG. 1, and FIG. 6 is a sectional view of the screen device, and FIG. 6 is a simplified sectional view of the paper making device. In this system, as a raw material, a paper container whose cross section is made of laminated paper of three kinds and five layers including layers of aluminum foil as shown in FIG. 2 is used. As shown in the figure, this laminated paper is
Polyethylene layer 1 of about 15-20 microns from the inside
Aluminum foil layer 12 of about 0,9 microns, polyethylene layer 14 of about 15 microns, 310-340 g /
Each layer consists of a base paper layer 16 of about m ² and a polyethylene layer 18 of about 15 microns.

To the pulper 20 shown in FIG. 3, 5 kg of caustic soda and 20 kg of hypochlorous acid are added to 1 ton of raw material. Here, caustic soda is for disintegrating the pulp, and hypochlorous acid is for bleaching the pulp. What is characteristic of this step is that instead of continuously feeding the raw material to the pulper 20, after the treatment with the pulper has been completed for a given amount of the fed raw material and the raw material is sent to the next step, the residue other than pulp remains. The point is that so-called batch processing is performed, in which only the plastic and metal foil of the product is discharged. In the conventional pulp regenerating method, since the regenerating process is performed only for the raw material containing no aluminum foil, it is possible to continuously convey the raw material by, for example, a conveyor or the like and put it in the pulper. However, in the case of a multi-layered paper including a layer of aluminum foil, it has been clarified that the treatment with the pulper does not proceed smoothly when the raw materials are continuously added because the whole deposition largely swells by absorbing moisture. Therefore, in this embodiment, by adopting the batch type processing method as described above, smooth processing can be performed.

Inside the tank 22 of the pulper 20, as shown in FIG. 3, an impeller (rotary blade) 24 for stirring the stock solution, and a stainless steel plate having a number of holes under the impeller 24 are provided. Screen 26 is provided. As shown in the enlarged view of FIG. 4, the distance between the back side of the impeller 24 and the screen 26 is significantly smaller than that of the conventional pulper and is about 2 mm. This is a result of bringing the rotating impeller and the screen closer to each other as much as possible within a range where they do not collide with each other due to manufacturing error or the like. In the conventional pulper, the gap between the impeller and the screen was larger than this, so there was a disadvantage that the crushed raw material was clogged in this gap. However, as a result of setting this interval to about 2 mm, this problem is solved. Furthermore, by narrowing the gap between the impeller and the screen in this way, turbulent flow is generated in the space between them, and the pulp that has settled on the screen without passing through the screen can be wound up above the impeller, It is possible to promote disaggregation and prevent clogging of the screen.

In the pulper 20, the raw materials and the above chemicals are charged, and the temperature is kept at about 40 ° C. and the mixture is stirred. At this time, while the pulp is disintegrated by stirring, it is desirable that the aluminum foil and polyethylene be made into large pieces so that they can be taken out easily. With this in mind, the impeller 24 is specially shaped so that it does not shatter the aluminum layer into pieces that are too fine and that there is a clear rotation at the top of the impeller. The impeller 24 is rotated by a motor of 150 horsepower, and the raw material and the chemicals are stirred for about 1 hour. This causes the pulp to disaggregate and pass through a screen having a 4 millimeter diameter hole 30 below the impeller. On the other hand, most of the aluminum and polyethylene are taken out as unnecessary substances from the gate valve 28 provided on the side surface of the tank.

By performing the treatment with the pulper 20 in this manner, about 99.1% of aluminum can be removed. However, the finely ground aluminum passes through the holes 30 in the screen along with the pulp. Therefore, too much aluminum is still mixed in to recycle the pulp into usable paper.

The pulp that has passed through the screen of the pulper 20 enters the beating refiner 34 through the porter 32. This beating refiner has a structure similar to that of a stone mill, and makes pulp pulp disintegrated into finer pieces.

The pulp discharged from the beating refiner 34 passes through a porcher 36 and enters a screen device 38 for removing dust. The screen device 38, as shown in FIG.
The impeller 40 is rotated and the pulp raw material supplied from the left side is pressurized to pass through the screen 42 having a slit hole with a diameter of 15/1000 inch. At this time, a large amount of water is supplied from the side of the impeller 40 to dilute the stock solution. This causes large aluminum strips that cannot pass through the screen 42 to be washed off the surface of the screen,
It is pulled out from the side of the screen device and sent to the tail screen 44 as a waste.

The stock solution that has passed through the screen device 38 is sent to the retention porch 48 through the washing machine 46, and the stock solution is retained therein for about 10 hours, for example. The retention porter 48 has a volume of 50 cubic meters, a propeller is provided inside the retention porter 48, and the propeller is rotated during the retention to stir the stock solution. By retaining the stock solution in the retention porter 48, it is possible to adjust the progress of processing by the operation of this system and the working time zone of the worker.

The stock solution that has passed through the staying porch 48 is sent to the screen device 54 through the porch washer 50 and the machine chest 52. The size of the screen hole of the screen device 54 is smaller than that of the screen device 38 in the preceding stage of the retention porch 48.
/ 1000 inch, but other configurations are the same as the screen device 38. Therefore, also in this case, a large amount of water can be used to efficiently remove the unwanted substances attached to the front side of the screen. The removed unwanted matter is sent to the tail screen 56.

The stock solution that has passed through the screen device 54 is sent to the paper making device 58. FIG. 6 is a simplified sectional view of the paper making device 58. The liquid sent from the screen device 54 is supplied from the right side of this drawing.

A vacuum suction unit 62 is provided at the center of the net 60, and the stock liquid 66 is drawn around the net 60 by vacuum suction. At this time 6
By rotating 0 in the direction of the arrow, only pulp fibers are adsorbed along the perimeter of the net. The pulp thus adsorbed is wound up on the couch roll 64 on the upper part of the net 60 to obtain a sheet of paper. Further, in the present embodiment, a so-called overflow method is adopted in which a large amount of water is added to the stock material liquid supplied from the screen device 54 to make paper. That is, the stock solution is diluted by adding about 1/3 of the volume of the original stock solution to water. By rotating the net 60 and vacuum suction in this state, a paper containing almost no aluminum was obtained.

The aluminum is removed and the pulp is regenerated through several steps as described above.
By removing most of the aluminum in
The efficiency of aluminum removal in the subsequent steps was improved, and finally it became possible to recycle the paper that contains practically no aluminum and can be put to practical use.

[0027]

As described above, according to the first invention, pulp can be taken out from a paper container or the like containing a metal foil such as aluminum, and most of the metal foil can be removed. Therefore, this pulper is used. By configuring the pulp recycling system with this method, it becomes easier to completely remove the metal in the steps after the pulper, it becomes possible to recycle the paper container containing the metal, and promote the recycling of used paper. It can respond to the social demand to preserve the natural environment.

According to the second invention, in addition to the above effects,
By making the gap between the impeller and the screen very narrow, such as 2 mm or less, it is possible to prevent fine particles such as aluminum from entering this gap and causing clogging, so that the pulp is disintegrated and the metal is removed. That work can proceed smoothly.

According to the third invention, in addition to the above effects,
By setting the hole of the screen to a value within the above range, the disintegrated pulp is easy to pass, and since it is possible to make it difficult to pass the fine particles of unnecessary materials such as aluminum,
It is possible to provide a pulper that can reduce the percentage of metal strips in the stock solution sent to the next step.

[Brief description of drawings]

FIG. 1 is a diagram showing a flow of a process of regenerating pulp from a used paper container or processing waste by a pulp regenerating system using a pulper according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of laminated paper used as a raw material in an example of the present invention.

FIG. 3 is a schematic cross-sectional view of a pulper that is an embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view showing the impeller and the vicinity of the screen shown in FIG.

FIG. 5 is a cross-sectional view of a screen device.

FIG. 6 is a simplified cross-sectional view of a papermaking device.

[Explanation of symbols]

 10,14,18 Polyethylene layer 12 Aluminum foil 16 Base paper layer 20 Pulper 22 Tank 24 Impeller 26 Screen 28 Gate valve 32,36 Retaining porter 34 Refining refiner 38,54 Screen device 46 Washer 48 Retaining porter 58 Paper machine 60 Circle net

Claims (3)

[Claims] 1. A tank is provided with a screen having a plurality of holes for passing disintegrated pulp and an impeller for stirring which rotates in a plane parallel to the screen, and a predetermined chemical and raw material. A certain amount of multi-layered paper containing metal foil is charged, the impeller is rotated, and the certain amount of raw material is subjected to pulp disintegration treatment, and then only the residual plastic and metal foil other than pulp are discharged. Pulper characterized by that. 2. The pulper according to claim 1, wherein the distance between the impeller and the screen is 2 mm or less. 3. The pulper according to claim 1, wherein the plurality of holes provided in the screen have a diameter within a range of 1 mm to 5 mm.