JP4937389B2 - Solid-liquid separation method and solid-liquid separation device - Google Patents

Description

  The present invention relates to a solid-liquid separation method and solid-liquid separation apparatus that remove fine solids from a processing liquid.

  As pre-painting treatment for automobile bodies and the like, chemical conversion treatment (zinc phosphate treatment) for forming a zinc phosphate film on a metal surface is performed (see, for example, Patent Document 1). Zinc phosphate treatment is effective not only for zinc-based plating materials and aluminum alloy materials, but also for steel materials, and is suitable as a base treatment for various coatings, particularly cationic electrodeposition coating. In the zinc phosphate treatment, a large amount of chemical sludge mainly composed of zinc phosphate compound is deposited at the bottom of the chemical conversion treatment tank. Zinc phosphate compounds are being shunned from an environmental point of view because they contain phosphorus, a eutrophic element.

  On the other hand, the zirconium-based chemical conversion treatment can form a necessary amount of coating on various materials, can improve corrosion resistance, coating adhesion, and the like, and can also reduce the burden on the environment.

JP 2002-52399 A

  However, a conventional pressure filtration apparatus is preferably used for removing chemical sludge having a particle diameter of about 20 μm deposited by zinc phosphate treatment, but the chemical sludge generated by zirconium-based chemical conversion treatment has a particle diameter of 3 μm. The following very fine iron hydroxides are included. The treatment liquid containing this chemical sludge has a slow sedimentation and poor filterability, and there is a problem that a large amount cannot be treated with a conventional pressure filtration treatment apparatus. There is also a physical pressure filtration method that removes the finer particles of chemical sludge by pre-coating filter media (filter paper) such as diatomaceous earth and discarding the diatomaceous earth together with the chemical sludge. Disposal with chemical sludge has the disadvantage of increasing the amount of waste.

  The present invention has been made in view of the above circumstances, and the object thereof is a solid-liquid separation method and solid-liquid separation capable of separating solids with a simple structure from a treatment liquid containing chemical sludge having a particle size smaller than that of a conventional particle size. To provide an apparatus.

Next, means for solving the above problems will be described with reference to the drawings corresponding to the embodiments.
In the solid-liquid separation method according to claim 1 of the present invention, the planar nonwoven fabric 17 that is supported and suspended only in the upper side is immersed in the treatment liquid 15 of the solid-liquid separation tank 13,
The solid material contained in the treatment liquid 15 is attached to the nonwoven fabric 17 by moving the nonwoven fabric 17 in the front and back direction in the direction of hitting the treatment liquid 15 on the front and back surfaces,
The filtrate in which the solid matter is reduced by the adhesion is discharged from the solid-liquid separation tank 13.

  In this solid-liquid separation method, when the nonwoven fabric 17 immersed in the treatment liquid in a suspended state is moved in the front and back direction, the treatment liquid 15 hits the nonwoven fabric 17 and a part of the treatment liquid 15 passes through the nonwoven fabric 17 and is treated. Solid matter contained in the liquid 15 adheres to the nonwoven fabric 17. This permeation and adhesion are repeated, so that the solid matter is deposited on the nonwoven fabric 17 and the solid matter is separated from the treatment liquid 15.

The solid-liquid separation method according to claim 2 is the solid-liquid separation method according to claim 1,
Stop draining the filtrate,
It is characterized in that air bubbles supplied from the bottom 47 of the solid-liquid separation tank 13 are applied to the nonwoven fabric 17 to release the solid matter attached thereto.

  In this solid-liquid separation method, the supply of the treatment liquid 15 is stopped, bubbles are generated at the bottom 47 in a state in which the treatment liquid 15 is stored, and the bubbles rising due to buoyancy are collided with the nonwoven fabric 17, thereby adhering solids. Objects can be detached from the nonwoven fabric 17. The non-woven fabric 17 from which the solid matter has been separated becomes capable of attaching the solid matter again.

The solid-liquid separation method according to claim 3 is the solid-liquid separation method according to claim 2,
Along with the supply of the bubbles, the nonwoven fabric 17 is lifted and lowered from the treatment liquid 15 so as to be raised and lowered with respect to the liquid surface.

  In this solid-liquid separation method, in addition to the collision of bubbles, the detachability of the solid matter from the nonwoven fabric 17 is further enhanced by the impact of the nonwoven fabric 17 being raised and lowered relative to the liquid surface.

The solid-liquid separation device 11 according to claim 4 is a solid-liquid separation tank 13;
A sheet-like nonwoven fabric 17 that is supported in the treatment liquid 15 of the solid-liquid separation tank 13 only and is immersed in a suspended state;
Non-woven fabric moving means 19 for moving the non-woven fabric 17 in the front and back direction in the direction of hitting the treatment liquid 15 on the front and back surfaces of the non-woven fabric 17;
An overflow outlet 21 for discharging the filtrate from which the solid matter has been reduced due to adhesion to the nonwoven fabric 17 from the solid-liquid separation tank 13;
It is characterized by comprising.

  While immersing the planar nonwoven fabric 17 in the treatment liquid 15 of the solid-liquid separation tank 13 and moving the nonwoven fabric 17 in a direction in which the treatment liquid 15 strikes the front and back surfaces, a portion of the treatment liquid 15 permeates the nonwoven fabric 17. The solid matter contained in the treatment liquid 15 is attached to the nonwoven fabric 17, and the filtrate from which the solid matter has been reduced by the attachment is discharged from the solid-liquid separation tank 13. This permeation and adhesion are repeated, so that the solid matter is deposited on the nonwoven fabric 17 and the solid matter is separated from the treatment liquid 15.

The solid-liquid separation device 11 according to claim 5 is the solid-liquid separation device 11 according to claim 4,
The nonwoven fabric 17 is characterized in that only the upper side portion 41 is fixed to the support bar 37.

  In this solid-liquid separator 11, only the upper side portion 41 of the nonwoven fabric 17 is supported by the support bar 37, and the immersed nonwoven fabric 17 is suspended in the processing liquid. When the support bar 37 is moved in the front and back direction of the nonwoven fabric 17 in this state, the movement transmitted to the upper side portion 41 of the nonwoven fabric 17 propagates to the lower side portion 43 in a wavy shape while allowing the nonwoven fabric 17 to be flexed. The entire front and back surfaces from the portion 41 to the lower side portion 43 can be uniformly applied to the treatment liquid 15.

The solid-liquid separation device 11 according to claim 6 is the solid-liquid separation device 11 according to claim 4 or 5,
A treatment liquid supply port 51 and a residue drain port 53 are provided at the bottom 47 of the solid-liquid separation tank 13.

  In this solid-liquid separation device 11, when removing the solid separated from the nonwoven fabric 17, the solid is settled over a predetermined time, and the residue drain port 53 is opened so that the solid deposited on the bottom 47 is removed from the nonwoven fabric 17. It is possible to discharge efficiently without reattaching. In the case where discharge remains in the bottom 47, cleaning can be performed by supplying the processing liquid 15 from the processing liquid supply port 51.

The solid-liquid separation device 11 according to claim 7 is the solid-liquid separation device 11 according to any one of claims 4, 5 and 6,
The non-woven fabric 17 is not in close contact with the front and back surfaces, has a space through which the treatment liquid 15 can pass, and is disposed on the front and back sides with the non-woven fabric 17 interposed therebetween. The net material 45 that is high and prevents the nonwoven fabric 17 from curling and guides the movement in the front and back direction is integrally fixed in a suspended state at the upper side in parallel.

  In this solid-liquid separator 11, the nonwoven fabric 17 suspended in the processing liquid is guided between the highly rigid net members 45 arranged on the front and back sides, and the net member 45 is in close contact with the front and back surfaces of the nonwoven fabric 17. The treatment liquid 15 has a space through which the non-woven fabric 17 is sandwiched and disposed on the front and back sides, so that the non-woven fabric 17 cannot be swollen by buoyancy or water flow. Further, the moving force transmitted to the upper side portion 41 is efficiently propagated to the lower side portion 43.

  According to the solid-liquid separation method of the first aspect of the present invention, solids can be separated with a simple structure from a treatment liquid containing chemical conversion sludge having a particle size smaller than that of the conventional particle size.

  According to the solid-liquid separation method of the second aspect, the solid matter adhering to the non-woven fabric can be detached with bubbles with a simple structure, and the replacement cycle of the non-woven fabric can be lengthened.

  According to the solid-liquid separation method of the third aspect, the detachability of the solid matter can be further enhanced by the impact when passing through the liquid level in addition to the bubbles.

  According to the solid-liquid separation device of the fourth aspect, it is possible to separate the solid matter with a simple structure from the processing liquid containing the chemical conversion sludge having a particle diameter finer than the conventional particle diameter.

  According to the solid-liquid separation device of claim 5, the nonwoven fabric immersed in a planar shape in the treatment liquid can be propagated to the lower side portion and shaken by the moving force transmitted to the upper side portion, with a small driving force. The treatment liquid can be applied to the entire surface of the nonwoven fabric to allow the solid matter to adhere uniformly to the nonwoven fabric.

  According to the solid-liquid separation device of the sixth aspect, the chemical conversion sludge accumulated at the bottom of the solid-liquid separation tank can be discharged and removed from the residue drain port by the processing liquid supplied from the processing liquid supply port.

  According to the solid-liquid separation device of the seventh aspect, when the nonwoven fabric is moved, the nonwoven fabric is sandwiched between the net materials having high rigidity, thereby preventing the occurrence of wrinkling that does not contribute to the filtration area.

It is a lineblock diagram showing notionally a solid-liquid separation device concerning the present invention. It is a side view of the filter medium unit which provided the nonwoven fabric and the net material alternately.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram conceptually showing a solid-liquid separation device according to the present invention, and FIG. 2 is a side view of a filter medium unit in which a nonwoven fabric and a net material are alternately provided.
The solid-liquid separation device 11 according to the present embodiment includes a solid-liquid separation tank 13, a planar nonwoven fabric 17 that is immersed in the treatment liquid 15 of the solid-liquid separation tank 13 and adheres solids contained in the treatment liquid 15, A nonwoven fabric moving means 19 for moving the nonwoven fabric 17 in a direction in which the treatment liquid 15 is hit against the front and back surfaces of the nonwoven fabric 17 is provided as a main configuration. The solid-liquid separation tank 13 is provided with an overflow discharge port 21 through which the filtrate whose solid matter is reduced due to adhesion to the nonwoven fabric 17 is discharged from the solid-liquid separation tank 13.

  In addition, the solid-liquid separation device 11 temporarily stores the sewage tank 23 for storing the processing liquid 15 supplied to the solid-liquid separation tank 13 and the processing liquid 15 discharged from the overflow discharge port 21 to form a chemical conversion (not shown). And a reflux tank 25 that returns to the treatment tank. The treatment liquid 15 in the sewage tank 23 is supplied to the solid-liquid separation tank 13 by a transfer pump 29 provided in a supply pipe 27 that connects the sewage tank 23 and the solid-liquid separation tank 13. In the solid-liquid separator 11, the processing liquid 15 after separating the solid is reused. Therefore, it is possible to remove solids only with filter media without using diatomaceous earth.

  The nonwoven fabric 17 is suspended above the solid-liquid separation tank 13 as a filter medium unit 31. In the present embodiment, a drive shaft 33 in a direction along the flow direction indicated by an arrow a in the drawing is rotatably supported, and the drive shaft 33 is rotated by the drive motor 35. The drive shaft 33 is provided with a plurality of, for example, three filter media units 31 as shown in the figure at predetermined intervals in the flow direction. The filter medium unit 31 has a support bar 37, and this support bar 37 is connected to the drive shaft 33 via the cam mechanism unit 39. The cam mechanism 39 reciprocates the support bar 37 in the direction along the drive shaft 33 when the drive shaft 33 is rotated.

  Note that the mechanism for moving the filter medium unit 31 in the same direction is not limited to this, and other mechanisms such as a cylinder mechanism, a link mechanism, and a pinion rack mechanism may be used as long as they can move in the same direction. There may be. Further, the movement of the filter medium unit 31 may be a swing (swinging) around a swinging shaft, a slide (a parallel movement in a direction perpendicular to the front and back surfaces), and the like.

  Only the upper side 41 of the nonwoven fabric 17 is fixed to the support bar 37. Only the upper side 41 of the nonwoven fabric 17 is supported by the support bar 37, and the immersed nonwoven fabric 17 is suspended in the treatment liquid. When the support bar 37 is moved in the front and back direction of the nonwoven fabric 17 in this state, the movement transmitted to the upper side portion 41 of the nonwoven fabric 17 propagates to the lower side portion 43 in a wavy shape while allowing the nonwoven fabric 17 to be flexed. The entire front and back surfaces from the portion 41 to the lower side portion 43 can be uniformly applied to the treatment liquid 15. By shaking (shaking) the nonwoven fabric 17 in a wave shape, the treatment liquid 15 can be applied to the entire surface of the nonwoven fabric 17 with a small driving force, and the solid matter can be uniformly attached to the nonwoven fabric 17.

  As shown in FIG. 2, in the filter medium unit 31, a net material 45 having substantially the same shape and higher rigidity than the nonwoven fabric 17 is integrally fixed in parallel on both sides of the nonwoven fabric 17. In the present embodiment, three net members 45 and two non-woven fabrics 17 are alternately arranged. The nonwoven fabric 17 suspended in the treatment liquid is guided between the net members arranged on the front and back sides, and the nonwoven fabric 17 cannot be swollen by buoyancy or water flow. Further, the moving force transmitted to the upper side portion 41 is efficiently propagated to the lower side portion 43. Thereby, at the time of the movement of the nonwoven fabric 17, the nonwoven fabric 17 is pinched | interposed into the highly rigid net | network material 45, and generation | occurrence | production of the wrinkle which does not contribute to a filtration area can be prevented.

  The filter medium unit 31 is detachable from the cam mechanism 39. That is, it can be exchanged. Further, each of the nonwoven fabric 17 and the net material 45 may be detachable from the support bar 37 and can be individually replaced.

More specifically, as will be described later, the nonwoven fabric 17 is preferably made of multiple layers of rayon and polyester in addition to using rayon alone as a material. Further, the thickness of the rayon nonwoven fabric is preferably 0.7 mm, and the basis weight is preferably about 150 g / m ² . The bubble point is preferably about 30 to 33 μm.

  The filter medium such as the nonwoven fabric 17 needs to be made of a material that allows the treatment liquid 15 to pass through to some extent. Further, the net material 45 and the nonwoven fabric 17 are not in close contact with each other, and it is preferable that there is a space through which the treatment liquid 15 can pass through the nonwoven fabric 17.

  The bottom 47 of the solid-liquid separation tank 13 is a V-shaped drain pan 49 having a low central portion. The bottom 47 is provided with a treatment liquid supply port 51 and a residue drain port 53. When removing the solids separated from the nonwoven fabric 17, the solids are allowed to settle for a predetermined time, and the residue drain port 53 is opened so that the solids deposited on the bottom portion 47 can be efficiently reattached to the nonwoven fabric 17. It is configured to discharge well. In the case where discharge remains in the bottom 47, cleaning can be performed by supplying the processing liquid 15 from the processing liquid supply port 51. Thereby, the chemical sludge collected in the bottom 47 of the solid-liquid separation tank 13 can be easily and quickly discharged and removed from the residue drain port 53 by the processing liquid 15 supplied from the processing liquid supply port 51.

  In addition, a bubble supply pipe 55 is provided at the bottom 47 of the solid-liquid separation tank 13 in a direction along the drive shaft 33. The bubble supply pipe 55 is provided with a plurality of bubble generation holes 57. An air generator (not shown) is connected to the bubble supply pipe 55, and the air generator generates bubbles in the processing liquid by releasing the compressed air supplied from the bubble generation holes 57. By applying the bubbles to the nonwoven fabric 17, the solid matter attached to the nonwoven fabric 17 is dropped to the bottom 47.

  In addition, although illustration is abbreviate | omitted, it is preferable that the solid-liquid separator 11 is equipped with the unit raising / lowering mechanism which pulls up the filter medium unit 31 from the process liquid 15, and repeats a fall. Thereby, the solid substance can be more efficiently detached by the quick raising / lowering operation together with the air bubbling. In addition, when the filter medium unit 31 is replaced, a unit lifting mechanism can be used.

  The solid-liquid separator 11 is provided with a control means (not shown). As the control means, a computer having an input / output interface, a programmable sequencer, or the like can be used. The control means controls driving of the transfer pump 29, driving of the driving motor 35, and driving of the air generator. Further, a turbidimeter provided in the solid-liquid separation tank 13 can be connected to the control means. Further, the control means controls the driving of the transfer pump 29, the drive motor 35, and the air generator by a built-in timer. Thereby, continuous operation is possible by repeating adhesion and dropping. Moreover, you may make it notify the replacement | exchange time of the nonwoven fabric 17 with a timer. By performing such repeated processing, the removal efficiency can be increased.

  Furthermore, a turbidimeter may be connected to the control means. The turbidimeter detects the timing of dropping the solids. A turbidimeter may be used to monitor the state of the solid-liquid separation tank 13 and grasp the state of adhesion of the nonwoven fabric 17 to obtain the air bubbling timing, the lifting / lowering timing of the filter medium unit 31, and the replacement timing. .

Next, a solid-liquid separation method using the solid-liquid separation device 11 will be described.
In the solid-liquid separation method according to the present embodiment, an example will be described in which solids are separated from the treatment liquid 15 generated in a chemical conversion treatment (zirconium chemical conversion treatment or phosphate coating treatment) before coating a metal. The basic operation is to place the treatment liquid 15 containing fine solid particles in the solid-liquid separation tank 13, soak the filter medium unit 31 on which the planar nonwoven fabric 17 is overlapped in the solid-liquid separation tank 13, and always process the filter medium unit 31. An operation of hitting the liquid 15 is performed, the treatment liquid 15 is brought into contact with the surface of the nonwoven fabric 17, and a solid matter is adhered to the separation treatment.

  The filtrate from which the solid matter has been reduced by the adhesion is discharged from the solid-liquid separation tank 13. When the nonwoven fabric 17 immersed in the treatment liquid is moved, the treatment liquid 15 hits the nonwoven fabric 17, a part of the treatment liquid 15 permeates the nonwoven fabric 17, and a solid substance contained in the treatment liquid 15 adheres to the nonwoven fabric 17. This permeation and adhesion is repeated, and solid matter is deposited and separated on the nonwoven fabric 17.

  After the elapse of a predetermined operation time, the transfer pump 29 is stopped, the discharge of the filtrate is stopped, the bubbles supplied from the bottom 47 of the solid-liquid separation tank 13 are applied to the nonwoven fabric 17 and the attached solid matter is released. The supply of the treatment liquid 15 is stopped, bubbles are generated at the bottom 47 in a state where the treatment liquid 15 is stored, and the bubbles rising due to buoyancy are caused to collide with the nonwoven fabric 17, thereby separating the attached solid matter from the nonwoven fabric 17. be able to. The non-woven fabric 17 from which the solid matter has been separated becomes capable of attaching the solid matter again. Thus, in the solid-liquid separator 11, the solid matter adhering to the non-woven fabric 17 can be separated with bubbles with a simple structure, and the replacement cycle of the non-woven fabric 17 can be lengthened.

  Further, when supplying the bubbles, the nonwoven fabric 17 is preferably pulled up and lowered from the treatment liquid 15. In addition to the collision of bubbles, the impact of moving the nonwoven fabric 17 up and down with respect to the liquid level further improves the detachability of the solid matter from the nonwoven fabric 17. Thereby, the detachability of the solid matter can be further improved.

  Therefore, according to the solid-liquid separation method and the solid-liquid separation apparatus 11 according to the present embodiment, solids are separated with a simple structure from the treatment liquid 15 containing chemical sludge having a particle diameter of 5 μm or less, which is smaller than the conventional particle diameter. it can.

  The solid-liquid separator 11 stops the supply of the processing liquid 15 to the solid-liquid separation tank 13 according to the result of the turbidimeter, and removes all of the processing liquid remaining in the solid-liquid separation tank 13 from the residue drain port 53. The tank is discharged, the inside of the tank is cleaned, the supply of the processing liquid 15 is newly started, and the processing is repeated. Further, the processing liquid 15 discharged from the residue drain port 53 may be returned to the sewage tank 23 again and repeatedly processed, or may be supplied to a separate solid-liquid separator and processed. Good. By performing discharge processing according to such turbidity, it is possible to improve the speed of the processing cycle. Further, after the solid matter was collected at the bottom of the solid-liquid separation tank 13 by supplying the bubbles as described above, that is, according to the result of the turbidimeter, the supply of the processing liquid 15 to the solid-liquid separation tank 13 was stopped and separated. After waiting for the solid matter to settle, the solid matter may be discharged from the residue drain port 53. By performing such repeated treatment (filtration), more solid matter can be separated.

  Further, the solid-liquid separation device 11 may be used as a pretreatment device for an existing solid-liquid separation (filtration) device. This makes it possible to make effective the removal capability of the solid particles having a specific particle size possessed by the present solid-liquid separation device, thereby reducing the load on the existing solid-liquid separation device in the subsequent stage.

  Furthermore, this solid-liquid separation device can also be configured in multiple stages. High purification can be realized by gradually reducing the solid content.

  Moreover, although the said embodiment demonstrated the example which isolate | separates a solid substance from the process liquid 15 which arises in the chemical conversion treatment before performing metal coating, the solid-liquid separation apparatus 11 concerning this invention is zirconium or phosphoric acid. It can also be suitably used when separating solids from this other treatment liquid 15 containing zinc compound sludge.

  Table 1 shows the results of putting each type of non-woven fabric into the zirconium coating solution and examining whether solid matter adheres to each non-woven fabric. Nine types of test pieces SP1 to SP9 were used. The size of the test piece was a strip shape having a width of 4 cm and a length of 14 cm. Other conditions such as the thickness of each test piece were as shown in Table 1 below.

As can be seen from Table 1, it was found that solid matter having a high basis weight and a small bubble point had poor adhesion of solid matter. In the case of the test piece SP7 and the test piece SP9, since the “strain” of the fiber was weak, it was difficult for the solid matter to adhere. It was found that the test pieces SP1 and SP2 having the rayon material, the thickness of 0.7 mm, and the basis weight of 150 g / m ² are optimal as the nonwoven fabric material.

DESCRIPTION OF SYMBOLS 11 ... Solid-liquid separator 13 ... Solid-liquid separation tank 15 ... Processing liquid 17 ... Nonwoven fabric 19 ... Nonwoven fabric moving means 21 ... Overflow discharge port 37 ... Supporting bar 41 ... Top side 45 ... Net material 47 ... Bottom 51 ... Processing liquid supply port 53. Residual drain port

Claims (7)

In the treatment liquid of the solid-liquid separation tank, only the upper side portion is supported and the planar nonwoven fabric in a suspended state is immersed,
The solids contained in the treatment liquid are attached to the nonwoven fabric by moving the nonwoven fabric in the front and back direction in the direction of hitting the treatment liquid on the front and back surfaces,
A solid-liquid separation method, wherein the filtrate in which the solid matter has been reduced by the adhesion is discharged from the solid-liquid separation tank. The solid-liquid separation method according to claim 1,
Stop draining the filtrate,
A solid-liquid separation method characterized in that air bubbles supplied from the bottom of the solid-liquid separation tank are applied to the non-woven fabric to remove the solid matter attached thereto. A solid-liquid separation method according to claim 2,
A solid-liquid separation method, wherein the nonwoven fabric is lifted and lowered so as to be lifted and lowered from the treatment liquid with the supply of the bubbles. A solid-liquid separation tank;
A sheet- like non-woven fabric supported only in the upper side and immersed in a suspended state in the treatment liquid of the solid-liquid separation tank,
Nonwoven fabric moving means for moving the nonwoven fabric in the front and back direction in the direction of hitting the treatment liquid on the front and back surfaces of the nonwoven fabric,
An overflow outlet for discharging the filtrate in which the solid matter is reduced due to adhesion to the nonwoven fabric from the solid-liquid separation tank;
A solid-liquid separation device comprising: The solid-liquid separator according to claim 4,
The non-woven fabric is a solid-liquid separator, wherein only the upper side is fixed to a support bar. The solid-liquid separator according to claim 4 or 5,
A solid-liquid separation apparatus, wherein a treatment liquid supply port and a residue drain port are provided at the bottom of the solid-liquid separation tank. The solid-liquid separation device according to any one of claims 4, 5, and 6,
The nonwoven fabric has a space through which the treatment liquid can pass without being in close contact with the nonwoven fabric, and is disposed on the front and back sides of the nonwoven fabric. The nonwoven fabric is substantially the same shape and has higher rigidity than the nonwoven fabric. A solid-liquid separation device characterized in that a net member that prevents dripping and guides the movement in the front and back direction is integrally fixed in a suspended state at the upper side in parallel.

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