JP2016022422A - Solid-liquid separation device and solid-liquid separation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a treatment amount with a simple structure in treatment for separating particle solid material from treatment liquid produced by zirconium type chemical treatment.SOLUTION: A solid-liquid separation device includes: a separation part 13 in which treatment liquid 23 produced by zirconium type chemical treatment is supplied to a separation tank 14, nonwoven fabric 25 is moved in the front and back direction in the treatment liquid 23 in the separation tank 14, thereby, particle solid material is attached, the released particle solid material is sedimented onto a bottom part 47 as concentrated slurry 57 and, at the same time, the treatment liquid from which the particle solid material is reduced is caused to overflow; a reflux part 17 in which the treatment liquid 23 made effluent from the separation part 13 is returned to a waste liquid tank 15; a slurry storage tank 19 which is connected by piping to the separation tank 14 and stores the concentrated slurry 57; and a filtration separator 21 in which a filter 71 is provided on a lower part 105 of the tank, an agitation plate 59 is vertically moved to agitate the concentrated slurry 57, filtration water passing through the filter 71 is discharged to an outer part 91 of the tank from the interior of a filtration chamber 61 and residue is gradually accumulated on the filter 71 to obtain dewatered cake 99.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solid-liquid separation device and a solid-liquid separation method.

  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

Conventionally, a pressure filtration treatment apparatus has been suitably used for removing chemical sludge having a particle diameter of about 20 μm deposited by zinc phosphate treatment.
However, in the chemical sludge generated by the zirconium-based chemical conversion treatment, particles of 0.1 to 5 μm are 61.26%, and particles of 5 to 10 μm are 30.98%. It is included. The treatment liquid containing the 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. That is, when the treatment liquid containing these particulate solids is separated by filtration with a conventional pressure filter, the filtration surface immediately becomes clogged during pressure filtration, and the amount of filtration is rapidly reduced. If it moves to the dehydration process by pressurized air in that state, since the amount of filtration is reducing, in order to process the liquid in a filtration chamber, a very long time is required.

  The present invention has been made in view of the above situation, and the object thereof is a process of separating particulate solids from a treatment liquid containing particulate solids such as fine iron hydroxide generated in a zirconium-based chemical conversion treatment. An object of the present invention is to provide a solid-liquid separation device and a solid-liquid separation method capable of increasing the throughput with a simple structure.

Next, means for solving the above problems will be described with reference to the drawings corresponding to the embodiments.
The solid-liquid separation device 11 according to claim 1 of the present invention stores a treatment liquid 23 containing solid particles having a particle diameter of 0.1 to 10 μm, which is composed of iron hydroxide generated in a zirconium-based chemical conversion treatment, as a liquid. Waste liquid tank 15,
A separation tank 14 to which the treatment liquid 23 is supplied from the waste liquid tank 15 is provided, and as a permeation performance that supports only the upper side portion 41 and is suspended, a planar shape having a bubble point average pore diameter of 30 to 33 μm at a water head pressure of 50 mm. The nonwoven fabric 25 made of short fiber nonwoven fabric is immersed in the treatment liquid 23 in the separation tank 14 in a direction along the vertical direction, and the nonwoven fabric 25 is moved in the front-back direction in a direction of hitting the treatment liquid 23 on the front and back surfaces. The solid particles contained in the treatment liquid 23 are adhered to the fibers constituting the nonwoven fabric 25, and then the bubbles 53 generated in the treatment liquid 23 of the separation tank 14 are caused to collide with the nonwoven fabric 25, and The non-woven fabric 25 is moved up and down with respect to the treatment liquid 23 and the solid particles separated from the treatment liquid 23 are precipitated as a concentrated slurry 57 on the bottom 47 of the separation tank 14. Rutotomoni, a separating portion 13 by overflowing the treatment fluid 23 which particles solids was reduced from the separation vessel 14,
A reflux unit 17 for returning to the waste liquid tank 15 while temporarily storing the treatment liquid 23 that has flowed out due to the overflow of the separation unit 13;
After being piped to the separation tank 14 bottom 47 and returning the treatment liquid 23 to the waste liquid tank 15 in the reflux section 17 for a predetermined time, it is discharged from the bottom 47 together with a part of the treatment liquid 23. A slurry storage tank 19 for storing the concentrated slurry 57;
The lower tank 105 is provided with a sheet-like filter 71 horizontally, and has a filtration chamber 61 to which the concentrated slurry 57 from the slurry storage tank 19 is supplied, and is close to the filtration chamber peripheral wall 107 above the filter 71. A horizontal stirring plate 59 provided with a plurality of through holes 87 having an opening ratio of 10 to 15% arranged with an edge portion 84 is provided in the middle of the height direction of the space 64 above the filter 71 in the filtration chamber. The concentrated slurry 57 is stirred and deposited on the filter 71 by moving it up and down at a speed of 1.8 to 2.1 m / min with a stroke length S at a distance of about half of the height in the space 64. The particle solids are not dispersed in the concentrated slurry so that the particle solids do not immediately settle and deposit on the filtration surface without causing the particle solids to rise. In addition, the inside of the filtration chamber 61 is not pressurized, the diaphragm pump 109 is used to perform suction filtration at a pressure of −500 to −600 mmHg, and the filtered water passing through the filter 71 is discharged to the outside of the tank 91, and gradually. A filter separator 21 for collecting the residue on the filter 71 to obtain a dehydrated cake 99;
It is characterized by including.

In the solid-liquid separator 11, the treatment liquid 23 generated in the zirconium-based chemical conversion treatment is stored in the waste liquid tank 15. The treatment liquid 23 stored in the waste liquid tank 15 is sent to the separation tank 14 of the separation unit 13. The separation unit 13 causes the processing liquid 23 to overflow when the supplied processing liquid 23 reaches a predetermined amount. The overflowed processing solution 23 is temporarily stored in the reflux tank 17. The processing liquid 23 accumulated in the reflux tank 17 is returned again to the waste liquid tank 15.
In the circulation system of the treatment liquid 23, in the separation unit 13, the nonwoven fabric 25 suspended vertically and immersed in the treatment liquid 23 is moved in the front and back direction. When the nonwoven fabric 25 is moved, the treatment liquid 23 hits the nonwoven fabric 25, a part of the treatment liquid 23 permeates the nonwoven fabric 25, and particle solids contained in the treatment liquid 23 adhere to (capture) the fibers of the nonwoven fabric 25. . This permeation and adhesion are repeated, so that the solid particles are deposited on the nonwoven fabric 25, and the solid particles are separated from the treatment liquid 23.
When a predetermined amount of particle solid matter adhering to the nonwoven fabric 25 or the operation time of the nonwoven fabric 25 reaches a predetermined time, bubbles 53 are generated from the lower part in the treatment liquid 23, and the bubbles 53 hit the nonwoven fabric 25, thereby causing the nonwoven fabric 25. The particulate solid adhering to the liquid falls to the bottom 47 of the separation tank 14. At this time, the nonwoven fabric 25 is moved up and down with respect to the treatment liquid 23, thereby more efficiently detaching the solid particles. The fallen solid particles settle on the bottom 47 of the separation tank 14. By repeating the collision of the bubbles 53 and the raising and lowering operation at predetermined intervals, the solid particles separated from the bottom 47 of the separation tank 14 are accumulated. Further, the treatment liquid 23 in which the particulate solids are reduced overflows from the separation tank 14. The overflowed processing liquid 23 is returned to the waste liquid tank 15 in the reflux unit 17, and this is repeated.
When the amount of solid particles deposited on the bottom 47 reaches a predetermined amount, for example, the number of repetitions of the ascending / descending operation, the operation time, or the accumulated amount (height) of the solid particles, the treatment liquid in the separation tank 14 When the turbidity of the liquid reaches a predetermined value, the treatment liquid 23 is discharged from the bottom 47 of the separation tank 14 to the slurry storage tank 19. As the processing liquid 23 is discharged from the bottom 47 of the separation tank 14, the particulate solid deposited on the bottom 47 of the separation tank 14 is preferentially discharged together with the processing liquid 23 as a concentrated slurry 57, thereby storing the slurry. It is sent to the tank 19.
The concentrated slurry 57 is stored in the slurry storage tank 19 and then sent to the filtration chamber 61 of the filtration separator 21. In the filtration chamber 61 to which the concentrated slurry 57 is supplied, the stirring plate 59 is moved up and down above the filter 71. At the same time, the concentrated slurry 57 supplied to the filtration chamber 61 passes through the filter 71 at the bottom 47 and the filtered water is discharged to the outside of the tank 91. This filtered water does not pressurize the filtration chamber on the upstream side of the filter (the side where the stirring plate 59 is disposed), and the filter 71 is filtered by suction filtration at a pressure of −500 to −600 mmHg using the diaphragm pump 109. It passes through and is discharged.
In the filtration chamber 61, the stirring plate 59 is moved up and down in the middle position in the filtration chamber 61 without causing the particle solid matter accumulated on the filter 71 to rise, so that the particle solid matter in the concentrated slurry is filtered. Immediately settles on the surface, making it difficult to deposit. The stirring plate 59 slowly settles on the filter 71 at a stirring speed in the filtration chamber 61 without breaking the solid particles. That is, the filter 71 is prevented from being clogged. Thereby, even if the treatment liquid 23 that passes through the filter 71 is in the state of the concentrated slurry 57, the sharp decrease in the filtration amount is improved by passing through a slight gap between the solid particles of the concentrated slurry 57. The
Further, the concentrated slurry 57 is sucked from the filtered water outflow side with the filter 71 interposed therebetween. Therefore, clogging of the filtration surface of the filter 71 is delayed as compared with pressure filtration in which the filter 71 is sandwiched and the concentrated slurry 57 on the stirring plate side is pressurized and passed through the filter 71. In other words, the concentrated slurry 57 is compressed from above (from a position opposite to the filter 71) to crush the soft and indefinite shape of the particle solids so that the particle solids are not in close contact with each other, and the filterable time of the filtration surface Becomes longer.
When the thickness of the particle solid matter captured on the filter reaches a predetermined thickness, the dry compressed air 119 is sent into the filtration chamber 61, whereby aeration dehydration is performed in which the residual liquid in the filtration chamber 61 is processed. . The aeration dehydration ends when the filtration chamber 61 reaches a set pressure or less and / or reaches a set time. The filtration chamber 61 is opened to the atmosphere by releasing the residual pressure and opening the valve. The dewatering cake 99 is opened in the filtration chamber 61 and discharged to the outside of the filtration chamber together with the filter 71, and the solid-liquid separation process ends.
In the solid-liquid separation device 11, the treatment liquid 23 before being processed by the filtration separator 21 is concentrated in advance by the separation unit 13 to become a concentrated slurry 57. This concentrated slurry 57 is sent to the filtration separator 21. By sending the concentrated slurry 57 to the filtration separator 21, the filtration separator 21 is more efficient in separating particulate solids than the case where the dehydrated cake 99 is obtained from the processing liquid 23 having a normal concentration stored in the waste liquid tank 15. Becomes higher. The processing amount of the processing liquid 23 per unit time increases. Therefore, in the solid-liquid separator 11, the processing time with respect to the processing amount can be shortened as compared with the case where the separation unit 13 and the filtration separator 21 are used alone. Further, the apparatus configuration is simplified as compared with the case where a plurality of filtration separators 21 are arranged in parallel.
Further, in particular, when the concentrated slurry 57 is passed through the filter 71 as in the configuration of the solid-liquid separation device 11, rapid clogging of the filter 71 is suppressed by using the stirring plate 59 in combination. . This increases the amount of processing. In the solid-liquid separator 11, the stirring plate 59 is used for the concentrated slurry 57 having a high concentration, so that the stirring operation by the stirring plate 59 is performed on the filtration surface compared to the case where the stirring plate 59 is used for the low-concentration treatment liquid 23. This is because it works more effectively in suppressing clogging.

The solid-liquid separation method according to claim 2 of the present invention is a waste liquid tank in which a treatment liquid 23 containing solid particles having a particle size of 0.1 to 10 [mu] m, whose component is iron hydroxide generated in a zirconium-based chemical conversion treatment, is contained in a liquid. A treatment liquid storage step to be stored in 15,
The treatment liquid 23 is supplied from the waste liquid tank 15 to the separation tank 14, and as a permeation performance for supporting only the upper side portion 41 and being suspended, a short surface with a bubble point average pore diameter of 30 to 33 μm at a head pressure of 50 mm is provided. The nonwoven fabric 25 made of a fiber nonwoven fabric is immersed in the treatment liquid 23 in the separation tank 14 in a direction along the vertical direction, and the nonwoven fabric 25 is moved in the front and back direction in a direction in which the treatment liquid 23 strikes the front and back surfaces. After the solid particles contained in the treatment liquid 23 are attached to the fibers constituting the nonwoven fabric 25, the bubbles 53 generated in the treatment liquid of the separation tank 14 are caused to collide with the nonwoven fabric 25, and the nonwoven fabric 25. The solid particles separated from the processing liquid 23 by being moved up and down with respect to the processing liquid 23 are precipitated as a concentrated slurry 57 on the bottom 47 of the separation tank 14. , A pre-stage separation step of overflowing the processing solution 23 which reduced the particle solids from the separation vessel 14,
A treatment liquid refluxing step for returning the treatment liquid 23 that has flowed out due to the overflow of the separation tank 14 to the waste liquid tank 15 while temporarily storing the treatment liquid 23 in the reflux tank 18;
A pipe is connected to the bottom 47 of the separation tank 14, and after returning the treatment liquid 23 to the waste liquid tank 15 in the treatment liquid refluxing process for a predetermined time, it is discharged from the bottom 47 together with the treatment liquid 23. A slurry storage step for storing the concentrated slurry 57 in the slurry storage tank 19, and
Using a filtration chamber 61 in which a sheet-like filter 71 is horizontally provided in the tank lower portion 105 and the concentrated slurry 57 from the slurry storage tank 19 is supplied, the filter 71 is close to the filtration chamber peripheral wall 107 above the filter 71. A horizontal stirring plate 59 provided with a plurality of through holes 87 having an opening ratio of 10 to 15% arranged with an edge portion 84 is provided in the height direction of the space 64 above the filter 71 in the filtration chamber 61. The concentrated slurry 57 is stirred by moving up and down at a speed of 1.8 to 2.1 m / min with a stroke length S at a distance of about half of the height in the space 64 at a substantially intermediate position. Disperse the particulate solids in the concentrated slurry so that the particulate solids that are deposited do not rise, and the particulate solids do not immediately settle and deposit on the filtration surface. However, the inside of the filtration chamber 61 is not pressurized, the diaphragm pump 109 is used to perform suction filtration at a pressure of −500 to −600 mmHg, and the filtered water passing through the filter 71 is discharged to the outside 91 of the tank. A filtration separation step of collecting the residue on the filter 71 to obtain a dehydrated cake 99;
It is characterized by comprising.

In this solid-liquid separation method, the treatment liquid 23 generated in the zirconium-based chemical conversion treatment is stored in the waste liquid tank 15 and sent to the separation tank 14 of the separation unit 13. The treatment liquid 23 in the separation tank 14 overflows and is once stored in the reflux tank 18 and then returned to the waste liquid tank 15 again.
In the separation tank 14, the non-woven fabric 25 suspended vertically and immersed in the treatment liquid 23 is moved in the front and back direction, a part of the treatment liquid 23 permeates the non-woven fabric 25, and the solid particles contained in the treatment liquid 23 are non-woven fabric 25. Adheres to (captures) the fibers. This permeation and adhesion are repeated, and the solid particles are separated from the treatment liquid 23. Further, the treatment liquid 23 in which the particulate solids are reduced overflows from the separation tank 14. The overflowed processing liquid 23 is returned to the waste liquid tank 15 in the reflux unit 17, and this is repeated.
The solid particles adhering to the nonwoven fabric 25 are generated by bubbles 53 from below in the treatment liquid, and the nonwoven fabric 25 is moved up and down with respect to the treatment liquid 23, whereby the separation is efficiently promoted. Precipitates at the bottom 47 of the.
The particulate solid deposited on the bottom 47 is preferentially discharged as a concentrated slurry 57 together with the processing liquid 23 as the processing liquid 23 is discharged from the bottom 47 of the separation tank 14, and is discharged to the slurry storage tank 19. Sent.
The concentrated slurry 57 stored in the slurry storage tank 19 is sent to the filtration chamber 61 of the filtration separator 21. In the filtration chamber 61, the stirring plate 59 is moved up and down above the filter 71. At the same time, the filtered water passes through the filter 71 at the bottom 47 and is discharged to the outside of the tank 91. The filtered water is discharged through the filter 71 by performing suction filtration at a pressure of −500 to −600 mmHg using the diaphragm pump 109 without pressurizing the inside of the filtration chamber 61 on the upstream side of the filter 71. In the filtration chamber 61, the concentrated slurry is stirred by the vertical movement of the stirring plate 59, so that the particulate solid deposited on the filter 71 does not rise and does not immediately settle and deposit. Slowly settle while dispersing without breaking.
Thereby, even if the treatment liquid 23 passing through the filter 71 is in the state of the concentrated slurry 57, the rapid decrease in the filtration amount is improved.
The concentrated slurry 57 sandwiches the filter 71 and is sucked from the filtered water outflow side, and the filtration possible time of the filtration surface becomes longer.
In this solid-liquid separation method, the treatment liquid 23 before being treated by the filtration separator 21 is concentrated in advance by the separation tank 14 to become a concentrated slurry 57. This concentrated slurry 57 is sent to the filtration separator 21. By sending the concentrated slurry 57 to the filtration separator 21, the filtration separator 21 increases the separation efficiency of the particle solid matter. The processing amount of the processing liquid 23 per unit time increases.
In particular, when the concentrated slurry 57 is passed through the filter 71, the clogging of the filter 71 is suppressed by using the stirring plate 59 in combination. This increases the amount of processing. In the solid-liquid separation method, the stirring plate 59 is used for the high-concentration concentrated slurry 57, so that the stirring operation by the stirring plate 59 is more effective than the case where the stirring plate 59 is used for the low-concentration treatment liquid 23. This is because it works more effectively in suppressing clogging.

  According to the solid-liquid separation device according to claim 1 of the present invention, in the process of separating the particulate solid from the treatment liquid containing the particulate solid such as fine iron hydroxide generated in the zirconium-based chemical conversion treatment, The amount of processing can be increased with a simple structure.

  According to the solid-liquid separation method of the second aspect of the present invention, it is possible to suppress a sudden clogging of the filtration surface and increase the processing amount.

It is a lineblock diagram showing the whole solid-liquid separation device concerning an embodiment of the present invention roughly. It is a perspective view of the isolation | separation part shown in FIG. (A) is an operation explanatory diagram when the rocking filter is moved front and back, (b) is an operation explanatory diagram of the overflow state of the separation tank, (c) is an operation explanatory diagram when bubbles are generated, and (d) is an oscillation filter rising It is operation | movement explanatory drawing at the time. It is front sectional drawing of the filtration separator shown in FIG. FIG. 5 is a plan sectional view of the filtration chamber shown in FIG. 4 and a plan view of a stirring plate. (A) is operation | movement explanatory drawing at the time of stirring plate lowering, (b) is operation | movement explanatory drawing at the time of stirring plate raising. (A) is operation | movement explanatory drawing at the time of dry air supply, (b) is operation | movement explanatory drawing at the time of filtration chamber opening. It is a graph showing the particle size distribution of a particle | grain solid substance. It is a graph showing the correlation with the throughput and the filtration time in a comparative example and an Example.

Embodiments according to the present invention will be described below with reference to the drawings.
FIG. 1 is a configuration diagram schematically showing the entire solid-liquid separation device 11 according to an embodiment of the present invention, and FIG. 2 is a perspective view of the separation unit 13 shown in FIG.
The solid-liquid separation device 11 according to the present embodiment includes a waste liquid tank 15, a separation tank 14, a reflux tank 18, a slurry storage tank 19, and a filtration separator 21.

  The waste liquid tank 15 stores a treatment liquid 23. This treatment liquid 23 is a liquid (solvent) obtained from a solid particle (solute) having a particle size of 0.1 to 10 μm having iron hydroxide as a component generated in a zirconium-based chemical conversion treatment performed as a pre-painting treatment for automobile bodies and the like. Is included.

  The separation unit 13 has a planar tank having a separation tank 14 to which a treatment liquid 23 is supplied and a non-woven fabric 25 that is immersed in the treatment liquid 23 in the separation tank 14 and adheres solid particles contained in the treatment liquid 23. The filter 27 and the nonwoven fabric rocking mechanism 29 that moves the rocking filter 27 in the direction in which the treatment liquid 23 strikes the front and back surfaces of the nonwoven fabric 25 are included as main components. The separation tank 14 is provided with an overflow outlet 31 through which the treatment liquid 23 (filtrate) in which the amount of solid particles is reduced due to adhesion to the nonwoven fabric 25 is discharged from the separation tank 14.

  The treatment liquid 23 is supplied from the waste liquid tank 15 to the separation tank 14. The processing liquid 23 discharged from the overflow outlet 31 of the separation tank 14 is temporarily stored in the reflux tank 18 of the reflux unit 17. The treatment liquid 23 in the waste liquid tank 15 is supplied to the separation tank 14 by a transfer pump 35 provided in a supply pipe 33 that connects the waste liquid tank 15 and the separation tank 14. In the solid-liquid separator 11, the treatment liquid 23 after separating the solid particles is returned from the reflux tank 18 to the waste liquid tank 15 (arrow 20 in FIG. 1) and reused. Therefore, it is possible to remove particulate solids using only the filter medium (the rocking filter 27) without using diatomaceous earth.

3A is an operation explanatory diagram when the swing filter 27 is moved front and back, FIG. 3B is an operation explanatory diagram of the overflow state of the separation tank 14, FIG. 3C is an operation explanatory diagram when bubbles are generated, and FIG. It is operation | movement explanatory drawing at the time of a rocking | fluctuation filter raising.
The nonwoven fabric 25 is suspended above the separation tank 14 as a filter medium unit. In the present embodiment, a plurality of, for example, seven swing filters 27 as shown in the figure are provided at predetermined intervals in the outflow direction of the processing liquid 23. The swing filter 27 has a support bar 37, and this support bar 37 is connected to the nonwoven fabric swing mechanism 29 via a cam mechanism unit 39. The cam mechanism unit 39 reciprocates the support bar 37 in a horizontal direction (in the direction of arrow a in FIG. 3) perpendicular to the extending direction of the support bar 37.

  The mechanism for moving the filter medium unit 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. May be. Further, the movement of the filter medium unit may be a swing (oscillation) around the oscillation axis, 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 25 is fixed to the support bar 37. Only the upper side portion 41 of the nonwoven fabric 25 is supported by the support bar 37, and the immersed nonwoven fabric 25 is suspended in the treatment liquid. When the support bar 37 is moved in the front and back direction of the nonwoven fabric 25 in this state, the movement transmitted to the upper side portion 41 of the nonwoven fabric 25 is propagated to the lower side portion 43 in a wavy shape while allowing the nonwoven fabric 25 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 processing liquid 23. By shaking (shaking) the nonwoven fabric 25 in a wave shape, the treatment liquid 23 can be applied to the entire surface of the nonwoven fabric 25 with a small driving force, and the solid particles can be uniformly attached to the nonwoven fabric 25.

  In the filter medium unit of the present embodiment, a net material 45 having substantially the same shape and higher rigidity than the nonwoven fabric 25 is integrally fixed in parallel on the front and back sides with the nonwoven fabric 25 interposed therebetween. In the present embodiment, three net members 45 and two non-woven fabrics 25 are alternately arranged. The nonwoven fabric 25 suspended in the treatment liquid is guided between the net members arranged on the front and back sides, and the nonwoven fabric 25 cannot be drowned 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 25, the nonwoven fabric 25 is pinched | interposed into the net material 45 with high rigidity, and generation | occurrence | production of the wrinkle which does not contribute to a filtration area can be prevented.

  The filter medium unit is detachable from the cam mechanism 39. That is, it can be exchanged. Each of the nonwoven fabric 25 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 25 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 that is a measure of the passage rate of the treatment liquid 23 is preferably about 30 to 33 μm.

  Note that the filter medium such as the nonwoven fabric 25 needs to be a material through which the treatment liquid 23 passes an appropriate amount. Further, the net material 45 and the nonwoven fabric 25 are not in close contact with each other, and as shown in FIG.

  The bottom 47 of the separation tank 14 becomes a V-shaped drain pan 49 having a low central portion. In the illustrated example, the V shape is omitted. The bottom 47 is provided with a treatment liquid supply port (not shown) and a residue drain port 51. When the solid particles separated from the nonwoven fabric 25 are excluded, the solid particles are allowed to settle over a predetermined time and the residual drain port 51 is opened to reattach the solid particles deposited on the bottom 47 to the nonwoven fabric 25. It is configured so that it can be discharged efficiently. In the case where discharge remains in the bottom 47, cleaning can be performed by supplying the processing liquid 23 from the processing liquid supply port. Thereby, the chemical conversion sludge collected in the bottom part 47 of the separation tank 14 can be easily and quickly discharged and removed from the residue drain port 51 by the processing liquid 23 supplied from the processing liquid supply port.

  A bubble supply pipe (not shown) is provided at the bottom 47 of the separation tank 14. The bubble supply tube is provided with a plurality of bubble generation holes. An air generator (not shown) is connected to the bubble supply pipe, and the air generator discharges the compressed air supplied from the bubble generation hole, so that the bubbles 53 shown in FIG. Generate from the bottom. By applying the bubbles 53 to the nonwoven fabric 25, the solid particles attached to the nonwoven fabric 25 are dropped onto the bottom 47.

  In addition, it is preferable that the solid-liquid separation apparatus 11 is provided with the unit raising / lowering mechanism 55 which repeats raising / lowering a filter medium unit from the process liquid 23 as shown in FIG.3 (d). Thereby, with the air bubbling described above, it is possible to detach the solid particles from the filter medium unit more efficiently by a quick lifting operation. The unit lifting mechanism 55 can also be used as a means for lifting the rocking filter 27 from the processing liquid 23 when the filter medium unit is replaced.

  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 the drive of the transfer pump 35, the drive motor, and the air generator. The control means controls the driving of the transfer pump 35, the drive motor, 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 25 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 particulate solid. The state of the separation tank 14 may be monitored with a turbidimeter, and the adhesion state of the nonwoven fabric 25 may be grasped to obtain the air bubbling timing, the lifting / lowering timing of the filter medium unit, and the replacement timing.

  As described above, in the separation unit 13, the processing liquid 23 is supplied from the waste liquid tank 15 and overflows, and the planar nonwoven fabric 25 that supports only the upper side 41 and is suspended is treated in the direction along the vertical direction. Immerse in. This non-woven fabric 25 is made of a short fiber non-woven fabric, and has a bubble point average pore diameter of 30 to 33 μm at a water head pressure of 50 mm as permeation performance, and is a multi-layered one of rayon and polyester. The separation tank 14 causes the solid particles contained in the treatment liquid 23 to adhere to the fibers constituting the nonwoven fabric 25 by moving the nonwoven fabric 25 in the direction of hitting the treatment liquid 23 against the front and back surfaces. Then, the separation tank 14 collides the bubbles 53 generated in the treatment liquid with the nonwoven fabric 25 and moves the nonwoven fabric 25 up and down relative to the treatment liquid 23 to remove the solid particles separated from the treatment liquid 23 at the bottom. 47, the concentrated slurry 57 shown in FIG. 3 (d) is precipitated, and the processing liquid with reduced particulate solids is allowed to overflow from the separation tank.

  The reflux unit 17 returns the treatment liquid 23 that has flowed out due to the overflow of the separation tank 14 to the waste liquid tank 15 while temporarily accumulating in the reflux tank 18. By this reflux, the separation process in the separation tank 14 can be performed more reliably, and the concentration of the solid slurry 57 of the solid particle in the treatment liquid 23 is increased.

  The slurry storage tank 19 is connected to the bottom 47 of the separation tank 14 and stores the concentrated slurry 57 that is preferentially discharged from the bottom 47 together with the processing liquid 23.

4 is a front sectional view of the filtration separator 21 shown in FIG. 1, and FIG. 5 is a plan sectional view of the filtration chamber 61 and a plan view of the stirring plate 59 shown in FIG.
In the filtration separator 21, the filtration chamber 61 includes a tray-like upper lid 63 and a lower lid 65, and the lower lid 65 is fixed to a drive shaft 69 of a hydraulic cylinder 67. The filtration chamber 61 is configured so that it can be closed and opened in the up-down direction when the lower lid 65 is moved up and down by a hydraulic cylinder 67, and for example, a paper-like filter 71 as a filter medium is connected to the upper lid 63 of the filtration chamber 61 closed. It is sandwiched from the front and back directions by the lower lid 65. The concentrated slurry 57 containing particulate solids sent to the filtration chamber 61 is sent to the inner filter and filtered.

  A concentrated slurry supply pipe 73 to which the concentrated slurry 57 is supplied is connected to the upper lid 63 of the filtration chamber 61. A first valve 75 for opening and closing the flow path is interposed in the concentrated slurry supply pipe 73. A pressure gauge 77 is connected to the upper lid 63.

  The stirring plate 59 moves up and down by the drive unit, and stirs the concentrated slurry 57 so that the particulate solid does not immediately accumulate on the filtration surface of the filter 71. A cylinder mechanism 79 can be employed as the drive unit of the stirring plate 59. A shaft 81 is fixed to the stirring plate 59, and this shaft 81 is driven up and down by a cylinder mechanism 79.

  The stirring plate 59 drives up and down in the space 64 above the filter 71 on the upper lid 63 side in the filtration chamber 61. In this space 64, the stirring plate 59 is disposed at a substantially intermediate position in the height direction, and moves up and down with a distance of about half the height as the stroke length S, that is, the ceiling surface in the upper lid 63 and the filter 71. Stirring is performed within a range where no contact occurs.

  The stirring plate 59 has substantially the same shape as the internal horizontal sectional shape of the filtration chamber 61, and has a slight gap 83 (see FIG. 5) between the inner surface of the filtration chamber and the edge 84 of the stirring plate 59, for example, It forms in the outer shape which made the clearance gap 83 about 5 mm with respect to the internal horizontal cross-sectional shape of the filtration chamber 61. FIG. Therefore, the stirring surface 85 is formed in the similar shape of the stirring plate 59 having substantially the same area as the filtration surface of the filter 71.

  In the stirring plate 59, a plurality of through holes 87 shown in FIG. The stirring plate 59 is formed with a plurality of through holes 87 so that the opening ratio is 10 to 15% with respect to the internal horizontal cross-sectional area of the filtration chamber 61. The gap 83 is substantially uniform along the edge 84 of the stirring plate 59, that is, the stirring plate 59 is positioned along the center in the filtration chamber 61, and the plurality of through holes 87 are the same. It is preferable to arrange them at regular intervals in the shape.

  The stirring plate 59 allows the concentrated slurry 57 to pass through the through hole 87 and reduces excessive resistance of the concentrated slurry 57 to the stirring plate 59. At the same time, the stirring plate 59 allows the particle solids to pass through the through-holes 87 and efficiently disperse the particle solids throughout the concentrated slurry 57. Thereby, stirring efficiency is improved. In addition, the inner diameter of the through-hole 87 is preferably such that the concentrated slurry 57 can pass smoothly without passing through the solid particles.

  A waste liquid pipe 89 is connected to the lower lid 65 of the filtration chamber 61, and the waste liquid pipe 89 discharges the filtered water in the filtration chamber 61 to the outside of the tank 91.

  In the filtration chamber 61, the lower lid 65 can be moved up and down by a hydraulic cylinder 67. The upper lid 63 and the lower lid 65 have an opening shape of, for example, a substantially square shape. Upper holding members 93 are provided on two parallel sides of the upper lid 63. Further, a lower holding member 95 facing the upper holding member 93 is also provided on two parallel sides of the lower lid 65. The upper holding member 93 and the lower holding member 95 sandwich the filter 71 when the upper lid 63 and the lower lid 65 are closed.

  The filter 71 is supported by a metal mesh in the lower lid and a filter medium support (not shown) made of punching metal.

  A filter moving means 97 is provided in the vicinity of the filtration chamber 61. The filter moving means 97 moves the filter 71 from the filtration chamber 61 when it is opened, and discharges the dehydrated cake 99 (see FIG. 7) from which the filtrate is removed from the concentrated slurry 57 together with the filter 71 to the outside of the tank 91. . The filter moving means 97 includes a filter feeding roll 101 that winds the filter 71 formed in a long band shape, and a filter winding that is provided on the opposite side of the filter feeding roll 101 with the filtration chamber 61 interposed therebetween and winds up the filter 71. A roll 103. The filter moving means 97 may be driven either manually or by motor drive. The filter moving means 97 can supply a new portion of the filter 71 to the filtration chamber 61 by rotating the filter winding roll 103 and the filter feeding roll 101 in synchronization.

  Thus, the filtration separator 21 has the filtration chamber 61 in which the sheet-like filter 71 is horizontally provided in the tank lower part 105 and the concentrated slurry 57 from the slurry storage tank 19 is supplied. The filtration separator 21 is provided with a plurality of through-holes 87 having an opening ratio of 10 to 15% arranged above the filter 71 and provided with an edge 84 adjacent to the peripheral wall 107 (see FIG. 5) of the filtration chamber. The agitating plate 59 is moved up and down in the space 64 above the filter 71 in the filtration chamber 61 at a speed of 1.8 to 2.1 m / min to slowly agitate the concentrated slurry 57. As a result, the particulate solid is dispersed in the concentrated slurry 57 so that the particulate solid does not immediately settle and deposit on the filtration surface. At the same time, the filtration separator 21 does not pressurize the filtration chamber, and uses the diaphragm pump 109 to perform suction filtration at a pressure of −500 to −600 mmHg to pass the filtered water passing through the filter 71 to the outside 91 of the tank. Discharge. The filter separator 21 gradually accumulates the residue (particle solids) on the filter 71 to obtain a dehydrated cake 99.

  The concentrated slurry supply pipe 73 is provided with a first electromagnetic valve 111 in addition to the first valve 75 for opening and closing the flow path. In addition, a pressure tube 113 is connected to the upper lid 63, and the pressure tube 113 is connected to the dry compressed air supply means 115. A second valve 117 for opening and closing the flow path is interposed in the pressurizing pipe 113. The dry compressed air supply means 115 sends the dry compressed air 119 to the filtration chamber 61 in the state where the supply of the concentrated slurry 57 is stopped, that is, the first valve 75 and the first electromagnetic valve 111 are closed. The residue is dehydrated by pressurizing with dry air so that the residue is pressed against the filter 71 and squeezed to obtain a dehydrated cake 99.

  Thus, in the filtration separator 21, the sheet-like filter 71 is provided inside the filtration chamber 61, and the concentrated slurry 57 containing particulate solids is sent, and the diaphragm pump 109 provided on the outlet side performs low-pressure suction. Filtration is performed.

  The filter 71 is sandwiched and stretched between the lower holding member 95 and the upper holding member 93. A scraper 121 is provided in the vicinity of the traveling path on the filter winding roll 103 side of the filter 71, and the scraper 121 scrapes off the dewatered cake 99 on the filter. The dewatered cake 99 that has been scraped off is dropped onto a waste tray 123 that is installed below.

Next, a solid-liquid separation method using the solid-liquid separator 11 will be described.
The solid-liquid separation method according to the present embodiment includes a treatment liquid storage process, a pre-stage separation process, a treatment liquid reflux process, a slurry storage process, and a filtration separation process.

  In the treatment liquid storage step, the treatment liquid 23 containing a solid particle having a particle diameter of 0.1 to 10 μm, which is composed of iron hydroxide generated in the zirconium-based chemical conversion treatment, is stored in the waste liquid tank 15.

  The outline of the preceding stage separation process is that the treatment liquid 23 is supplied from the waste liquid tank 15 to the separation tank 14 and overflows, and the bubble point average pore diameter at a head pressure of 50 mm is the permeation performance that supports only the upper side 41 and is suspended. A non-woven fabric 25 made of a sheet-like short fiber non-woven fabric of 30 to 33 μm is immersed in the treatment liquid 23 in a direction along the vertical direction. By moving the nonwoven fabric 25 in the front and back direction in the direction in which the treatment liquid 23 strikes the front and back surfaces, the solid particles contained in the treatment liquid 23 are attached to the fibers constituting the nonwoven fabric 25. While causing the bubbles 53 generated in the lower part of the processing liquid to collide with the nonwoven fabric 25, the nonwoven fabric 25 is moved up and down with respect to the processing liquid 23. As a result, the particulate solid adhered to the fibers easily falls, and the particulate solid separated from the treatment liquid 23 is precipitated as a concentrated slurry 57 on the bottom 47. Further, the treatment liquid 23 in which the particulate solids are reduced overflows from the separation tank 14. This overflowed processing solution is so-called supernatant.

  In addition, when the nonwoven fabric 25 immersed in the treatment liquid 23 is moved, the treatment liquid 23 hits the nonwoven fabric 25, a part of the treatment liquid 23 permeates the nonwoven fabric 25, and the solid particles contained in the treatment liquid 23 are the nonwoven fabric 25. Adhere to fibers. This permeation and adhesion are repeated, and the solid particles are adhered and separated one after another so that the solid particles are deposited on the nonwoven fabric 25. The treatment liquid 23 in which the particle solids are reduced is discharged from the overflow discharge port 31 by the movement of the non-woven fabric 25, and the liquid surface moves like ripples in the separation tank 14.

  The non-woven fabric 25 from which the solid particles have been separated can adhere to the solid particles again. As described above, in the separation tank 14, the solid particles adhering to the nonwoven fabric 25 can be separated by the bubbles 53 with a simple structure, and the replacement cycle of the nonwoven fabric 25 can be lengthened.

  Further, when supplying the bubbles 53, the nonwoven fabric 25 is pulled up and lowered from the treatment liquid 23. In addition to the collision of the bubbles 53, the impact of moving the nonwoven fabric 25 up and down with respect to the liquid level further enhances the detachability of the solid particles from the nonwoven fabric 25. Thereby, the releasability of the particle solid is further improved.

  Therefore, in the separation part 13, a treatment including a chemical sludge having a particle size of 5 μm or less smaller than the conventional particle size is performed by the non-woven fabric 25 configured by intricately intertwining fibers rather than a filter in which simple holes are formed through. The solid particles can be separated from the liquid 23 with a simple structure, and the non-woven fabric 25 having a bubble point average pore diameter of 30 to 33 μm allows the treatment liquid 23 to easily pass between fibers with a particle size of 0.1. It can be separated from the treatment liquid 23 by adhering a particle solid of 10 μm so as to be caught on the fiber.

  The separation unit 13 stops the reflux unit 17 (described later) and stops the supply of the processing liquid 23 according to the result of the turbidimeter or the elapse of a predetermined time, and stops the supply of the treatment liquid 23 to remove the concentrated slurry 57 remaining in the separation tank 14. Eject all from 51. Thereafter, the inside of the tank is cleaned. After the cleaning, the supply of the treatment liquid 23 is newly started and the treatment is repeated. Also, the cleaning processing liquid 23 discharged from the residue drain port 51 is returned again to the waste liquid tank 15 and repeatedly processed.

  In the solid-liquid separation device 11, the separation unit 13 is used as a pretreatment device for the filtration separator 21. Thereby, the removal capability of the specific particle | grain solid substance which the separation part 13 has can be made effective, and the load of the filtration separator 21 of a back | latter stage can be reduced significantly.

  In the treatment liquid refluxing step, the treatment liquid 23 that has flowed out due to the overflow of the separation part 13 is returned to the waste liquid tank 15 while being temporarily accumulated in the reflux tank 18 at the reflux part 17. Thereby, the continuous production | generation of the concentration slurry 57 by the continuous process of the process liquid 23 is attained, and the separation process in the separation tank 14 can be performed more reliably by repeating this recirculation | reflux, and the particulate solid in the process liquid 23 The concentration of the concentrated slurry 57 is increased, and the separation of the solid particles from the treatment liquid 23 is further enhanced.

  In the slurry storage step, the concentrated slurry 57 that is preferentially discharged together with the treatment liquid 23 from the bottom 47 of the separation tank 14 is stored in the slurry storage tank 19 connected to the bottom 47 of the separation tank 14.

6A is an operation explanatory diagram when the stirring plate is lowered, FIG. 6B is an operation explanatory diagram when the stirring plate is raised, FIG. 7A is an operation explanatory diagram when supplying dry air, and FIG. It is operation | movement explanatory drawing at the time.
The outline of a filtration separation process uses the filtration chamber 61 which equips the tank lower part 105 with the sheet-like filter 71 horizontally, and the concentrated slurry 57 from the slurry storage tank 19 is supplied. In the filtration chamber 61 of the filtration separator 21, a horizontal stirring plate provided with a plurality of through-holes 87 having an opening ratio of 10 to 15% arranged with an edge portion close to the filtration chamber peripheral wall 107 above the filter 71. 59 is moved up and down to slowly stir the concentrated slurry 57. Stirring by the stirring plate 59 is performed at a substantially intermediate position in the height direction of the space 64 above the filter 71 in the filtration chamber 61, and a distance of approximately half of the height in the space 64 is 1.8 to It is considered to move up and down at a speed of 2.1 m / min. The particle solids do not immediately settle on the filtration surface and do not accumulate without causing the particle solids deposited on the filter 71 to rise and without damaging the particle solids with the stirring plate 59. Disperse the particulate solid in the concentrated slurry. At the same time, the filtration separator 21 does not pressurize the inside of the filtration chamber 61, and uses the diaphragm pump 109 to perform suction filtration at a pressure of −500 to −600 mmHg to pass the filtered water passing through the filter 71 to the outside 91 of the tank. Discharge. As a result, the filtration separator 21 gradually accumulates the residue on the filter 71 to obtain a dehydrated cake 99.

  In the filtration method using the filtration separator 21, first, the concentrated slurry 57 containing particulate solids is sent to the sheet-like filter 71 in the filtration chamber 61 by a supply pump. At the same time, low-pressure suction filtration is performed by a diaphragm pump 109 provided on the outlet side of the filtration chamber 61. When the filtration chamber 61 is decompressed, that is, sucked and filtered by the diaphragm pump 109, it is not necessary to send compressed air to the filtration chamber 61. The concentrated slurry 57 is continuously fed into the filtration chamber 61 and simultaneously filtered under reduced pressure through the filter 71 by the diaphragm pump 109. At the time of feeding, the pressure of feeding the concentrated slurry 57 is low. Since the concentrated slurry 57 is continuously fed into the filtration chamber space, the residue gradually accumulates in the filter 71. At this time, as shown in FIG. 6, the stirring plate 59 provided on the inlet side of the filtration chamber 61 is moved up and down by a stroke S, and filtration is performed while slowly stirring so that the particulate solid does not accumulate on the filtration surface. In the up / down stroke of the stirring plate 59, the stirring plate 59 is set to a height that does not touch the residue accumulated on the filter 71 at the lower end of the stroke, that is, only the concentrated slurry 57 is stirred in the filtration chamber 61.

  When a predetermined time or when a predetermined flow rate is reached, or when a change in the suction pressure of the diaphragm pump 109 is observed, liquid feeding is stopped and suction (decompression) is stopped. The stop timing is determined by various sensors in addition to a timer in the case of time, a flow meter provided in the waste liquid pipe 89 in the case of flow rate, and a pressure gauge 90 provided in the waste liquid pipe 89 in the case of pressure. Also good. In this filtration and separation step, the solid particles are crushed by compression and deformed one after another, and the solid particles on the surface side (upstream side) opposite to the filter are in close contact with each other, clogging and flowing the liquid. Compared with the pressure filtration which becomes difficult, the solid particles are not crushed so much, the liquid flows from the gap 83 between the particles to the tank lower portion 105 without resistance.

  In the dehydration step, as shown in FIG. 7A, after the supply pump on the concentrated slurry supply pipe 73 side is stopped, dry compressed air 119 is sent into the filtration chamber 61, and the compressed air pressure is applied to the upper surface of the filter. In addition, moisture is squeezed out. In this dehydration step, the moisture content of the dehydrated cake 99 is reduced, and thereby the adhesiveness is reduced, whereby the dehydrated cake 99 is easily peeled off from the filter 71. When the squeezing out of the water is completed, the lower lid 65 is lowered by the hydraulic cylinder 67 to open the filtration chamber 61 as shown in FIG. After the filtration chamber 61 is opened, the filter 71 is moved by the filter moving means 97, and the dehydrated cake 99 is discharged to the outside of the tank 91 together with the filter 71.

  The dehydrated cake 99 discharged to the outside 91 of the filtration chamber 61 is scraped off by the scraper 121, separated from the filter 71, and dropped onto the waste tray 123. The filter 71 from which the dewatered cake 99 has been removed is taken up by the filter take-up roll 103 and becomes reusable.

Next, the operation of the solid-liquid separation device 11 having the above configuration will be described.
In the solid-liquid separator 11 according to this embodiment, the treatment liquid 23 generated in the zirconium-based chemical conversion treatment is stored in the waste liquid tank 15. The treatment liquid 23 stored in the waste liquid tank 15 is sent to the separation tank 14 of the separation unit 13. The separation unit 13 causes the processing liquid 23 to overflow when the supplied processing liquid 23 reaches a predetermined amount. The overflowed processing solution 23 is temporarily stored in the reflux tank 18. The treatment liquid 23 accumulated in the reflux tank 18 is returned again to the waste liquid tank 15.

  In the circulation system of the treatment liquid 23, in the separation tank 14, the nonwoven fabric 25 immersed in the treatment liquid 23 along the vertical direction is moved in the front and back direction. When the nonwoven fabric 25 is moved, the treatment liquid 23 hits the nonwoven fabric 25, and a part of the treatment liquid 23 permeates the nonwoven fabric 25, and particle solids contained in the treatment liquid 23 adhere to the fibers of the nonwoven fabric 25. This is because the solid particles are indefinite shape and the fibers constituting the non-woven fabric 25 are intertwined, so that the solid particles that float are trapped while the treatment liquid 23 passes between the fibers. It is. That is, as the configuration of the nonwoven fabric 25, the bubble point average pore diameter is set to 30 to 33 μm as described above, but this hole is not a tubular hole that passes straight through the nonwoven fabric, but an indefinite shape that configures the nonwoven fabric 25. The pore diameter value of the bubble point in a state where the fibers are intertwined, and the solid particles are trapped and attached so as to be caught in the gap portion of the irregular shape formed by the fibers. This permeation and adhesion are repeated, and particle solids are deposited on the nonwoven fabric 25, and the particle solids are separated from the treatment liquid 23. Further, the processing liquid 23 in which the particulate solids are reduced is caused to overflow from the separation tank 14.

  When the solid particle adhering to and depositing on the non-woven fabric 25 reaches a predetermined amount or when the non-woven fabric 25 is moved for a predetermined time, bubbles 53 are generated from the lower part in the treatment liquid, and the air bubbles 53 strike the non-woven fabric 25. The particulate solid adhering to 25 falls to the bottom 47 of the separation tank 14. At this time, the non-woven fabric 25 is moved up and down with respect to the treatment liquid 23, whereby the separation of the solid particles is promoted more efficiently. The fallen solid particles settle on the bottom 47 of the separation tank 14. Since the solid particles trapped in the nonwoven fabric 25 are agglomerated to some extent, the specific gravity is increased and the particles are easily settled to the bottom 47. The particle solid matter is only attached to the nonwoven fabric 25, and falls easily due to the impact of air bubbles or lifting operation. At this time, the supply of the treatment liquid 23 to the separation tank 14 may be continued or stopped. By repeating the collision of the bubbles 53 and the raising and lowering operation at predetermined intervals, the solid particles separated from the bottom 47 of the separation tank 14 are accumulated.

  After the refluxing unit 17 repeats the refluxing of the overflowed processing liquid to the waste liquid tank 15 for a predetermined time, when the amount of solid particles deposited on the bottom 47 reaches a predetermined amount, the processing liquid 23 is slurried from the bottom 47 of the separation tank 14. It is discharged to the storage tank 19. As the processing liquid 23 is discharged from the bottom 47 of the separation tank 14, the particulate solid deposited on the bottom 47 of the separation tank 14 becomes the concentrated slurry 57 together with the processing liquid 23 and is discharged preferentially (the discharge flow). It receives resistance and moves downstream) and is sent to the slurry reservoir 19.

  The concentrated slurry 57 is stored in the slurry storage tank 19 and then sent to the filtration chamber 61 of the filtration separator 21. In the filtration chamber 61 to which the concentrated slurry 57 is supplied, the stirring plate 59 is moved up and down above the filter 71. At the same time, the concentrated slurry 57 supplied to the filtration chamber 61 passes through the filter 71 at the bottom 47 and the filtered water is discharged to the outside of the tank 91. This filtered water is filtered by suction filtration at a negative pressure of −500 to −600 mmHg using the diaphragm pump 109 without pressurizing the filtration chamber on the upstream side of the filter (the side where the stirring plate 59 is disposed). It passes through 71 and is discharged.

  In the filtration chamber 61, the stirring plate 59 is moved up and down, so that the solid particles in the concentrated slurry are less likely to settle and accumulate on the filtration surface. That is, the filter 71 is prevented from being clogged. In other words, due to the slow up and down movement of the stirring plate 59, the solid particles are not immediately settled on the filter 71 in the filtration chamber 61, and the solid particles are suspended by the stirring plate 59 having the through holes 87. Therefore, the suction filtration by the filter 71 can be continued, so that the precipitation of the solid particles is delayed and does not accumulate on the filter 71 one after another. Thereby, even if the treatment liquid 23 passing through the filter 71 is in the state of the concentrated slurry 57, the rapid decrease in the filtration amount is improved. This action exerts a remarkable effect particularly in the present configuration in which the concentrated slurry 57 is filtered.

  Further, the concentrated slurry 57 is sucked from the filtered water outflow side with the filter 71 interposed therebetween. Therefore, clogging of the filtration surface of the filter 71 is delayed as compared with pressure filtration in which the filter 71 is sandwiched and the concentrated slurry 57 on the stirring plate side is pressurized and passed through the filter 71. That is, in the pressure filtration, the concentrated slurry 57 on the filter 71 is compressed on the surface side opposite to the filter 71, and the solid particles are brought into close contact with each other. The clogging of the surface and the degree of adhesion of the accumulated concentrated slurry 57 itself will eliminate the passage of filtered water, but this does not occur in the suction filtration through the filter 71, and the filtration time on the filtration surface is long. (The filter 71 lasts longer).

  When the thickness of the solid particles trapped on the filter reaches a predetermined thickness, or when the concentrated slurry 57 hardly passes through the filter 71 and the suction pressure changes, the dry compressed air 119 is sent. The ventilation dehydration is performed in which the residual liquid in the filtration chamber 61 is processed. The aeration dehydration ends when the filtration chamber 61 reaches a set pressure or less and / or reaches a set time. The filtration chamber 61 is opened to the atmosphere by releasing the residual pressure and opening a valve (not shown). The dewatering cake 99 is opened to the filtration chamber 61 and discharged to the outside of the tank 91 together with the filter 71, and the solid-liquid separation process ends.

  As described above, in the solid-liquid separation device 11, the treatment liquid 23 before being processed by the filtration separator 21 is concentrated in advance by the separation unit 13 to be a concentrated slurry 57. The concentrated slurry 57 is sent to the filtration separator 21, so that the filtration separator 21 is more solid than the case where the dehydrated cake 99 is obtained from the normal low-concentration treatment liquid 23 stored in the waste liquid tank 15. The separation efficiency of the is greatly increased. Therefore, the solid-liquid separator 11 can shorten the processing time compared to the case where the separation unit 13 and the filtration separator 21 are used alone. Further, the apparatus configuration is simplified as compared with the case where a plurality of filtration separators 21 are arranged in parallel.

  In particular, when the concentrated slurry 57 is passed through the filter 71 as in the configuration of the solid-liquid separator 11, the filter 71 can be rapidly clogged by using the stirring plate 59 in combination in the filtration chamber 61. It is suppressed. By using the stirring plate 59 for the high concentration concentrated slurry 57, the stirring operation by the stirring plate 59 is more effective in suppressing clogging of the filtration surface than when the stirring plate 59 is used for the low concentration treatment liquid 23. This is because it works effectively.

  In the solid-liquid separation method according to the present embodiment, the treatment liquid 23 generated in the zirconium-based chemical conversion treatment is stored in the waste liquid tank 15 and sent to the separation unit 13. The action and effect described above are low for other processing solutions. That is, the solid-liquid separation device 11 can obtain a great effect by being used for the zirconium-based chemical conversion treatment. This is considered to be due to the fact that iron hydroxide is easily attached to the nonwoven fabric 25 and captured, and the passage of the filter 71 can be improved by stirring the concentrated slurry 57 obtained by the stirring plate 59. .

  Therefore, according to the solid-liquid separation device 11 according to the present embodiment, in the process of separating the particulate solid from the treatment liquid 23 containing the particulate solid such as fine iron hydroxide generated in the zirconium-based chemical conversion treatment, The amount of processing can be increased with a simple structure.

  Moreover, according to the solid-liquid separation method which concerns on this embodiment, the clogging of the filtration surface can be suppressed and a processing amount can be increased.

The treatment test of the cleaning slurry liquid was performed by the actual machine of the solid-liquid separator 11 having the same configuration disclosed in the above embodiment.
[Test purpose]
A sample liquid was prepared by assuming a treatment liquid 23 after the particulate solid was captured by the separation unit 13 having the same configuration as above for the chemical conversion liquid in the zirconium-based chemical conversion treatment line. Using a filtration separator 21 constituting an actual machine (EFC-10S: manufactured by Sankyo Giken Kogyo Co., Ltd.), a method of performing suction filtration with stirring (Example) and a conventional method of performing suction filtration without stirring The difference in the processing time between (Comparative Example 1) and the method of performing pressure filtration while stirring (Comparative Example 2) was verified.

[Test sample]
Test sample name: Zirconium-based chemical conversion treatment liquid Test sample collection date: November 19, 2012 Test sample collection place: Collected from the bottom of the chemical conversion sludge concentration tank.
Solid particle size: 1-5 μm (61.25%), 5-10 μm (30.98%)
FIG. 8 is a graph showing the particle size distribution of the solid particles.
In addition, in the graph of FIG. 8, the total number of white bars from those having a large particle diameter was 100%. The hatched bar represents the frequency between the particles. For example, the particle composition ratio is about 61.25% for particles of 0 to 5 μm and about 30.98% for particles of 5 to 10 μm.

[tank capacity]
It was 500 liters.
[Concentration of cleaning solution]
441.35 g ÷ 500 liters = 0.882 g / liter, where ≈1 g / liter.
[Collecting liquid concentration]
It was 17.4 g / liter.
[Test sample]
A liquid obtained by diluting the collected liquid 17.4 times with clean water was used as a test sample.
[Test date]
December 26-27, 2012 [Test method for filtration separator]
Suction filtration method (using diaphragm pump)
The shape of the filtration chamber 61 is as shown in FIG. 5 described above. The inner dimensions of the upper lid 63 are 260 mm in length and 320 mm in width, four corners are formed with a radius of 60 mm, and the dimensions of the stirring plate 59 are R is formed with a radius of 55 mm and a radius of 55 mm, circular through-holes 87 are arranged at equal intervals, each has a diameter of 20 mm, and 18 holes are drilled. The area of the upper lid 63 is 0.0801 m ^2. The area of the stirring plate 59 is 0.0692453 mm ² , the area of the opening is 0.0108547 m ² , and the opening ratio is 13.55%.
The size of the space 64 in the filtration chamber 61 is such that the distance from the upper surface of the filter 71 to the ceiling surface of the upper lid 63 is 70 mm, the stroke length S of the stirring plate 59 in the space 64 is 30 mm, and the stroke lower limit position of the stirring plate 59. The distance to the filter 71 is 15 mm, and the volume is 0.00637 m ³ .
Filter paper (filter 71): 05TH-100H (average particle size 13.9 μm)
-Filtration area: 0.091 m ²
・ Upper and lower cylinder speed: 2.1m / min (70 times / min)

Comparative Example 1: Suction filtration (−500 to −600 mmHg) was performed with a diaphragm pump, and no stirring was performed.
Comparative Example 2: In addition to performing suction filtration (−500 to −600 mmHg) with a diaphragm pump, pressure filtration (0.04 Mpa) was performed, and stirring in the filtration chamber was performed.
Example: Suction filtration (-500 to -600 mmHg) was performed with a diaphragm pump, and the filtration chamber was stirred without being pressurized.
Table 1 shows the results obtained by performing the test under the above conditions.

As shown in Table 1, in the example, the throughput per unit time was a maximum at 679.9 liters / m ² · Hr. In the example, the filtration / dehydration time until the dewatered cake thickness reached 4.0 mm, which was the same as that in the comparative example, was as long as 160 min. That is, it was found that clogging was suppressed by suction filtration.

[Discussion]
FIG. 9 is a graph showing the correlation between the throughput and the filtration time in the comparative example and the example.
Compared with the conventional filtration method of Comparative Example 1, it was found that the treatment time was reduced by 1.49 times when suction filtration was performed while stirring the filtration chamber of the Example.
From this result, it was found from the results of Comparative Example 2 that the amount of treatment was increased when pressure was not increased in the filtration chamber as much as possible.

DESCRIPTION OF SYMBOLS 11 ... Solid-liquid separator 13 ... Separation part 14 ... Separation tank 15 ... Waste liquid tank 17 ... Recirculation | reflux part 19 ... Slurry storage tank 21 ... Filtration separator 23 ... Treatment liquid 25 ... Nonwoven fabric 41 ... Upper side part 47 ... Bottom part 53 ... Bubble 57 ... Concentrated slurry 59 ... Stirrer plate 61 ... Filtration chamber 64 ... Space 71 ... Filter 84 ... Edge 87 ... Through hole 91 ... Outside the tank 99 ... Dehydrated cake 105 ... Lower tank 107 ... Filtration chamber peripheral wall 109 ... Diaphragm pump S ... Stroke

Claims (2)

A waste liquid tank in which a treatment liquid containing solid particles having a particle size of 0.1 to 10 μm containing iron hydroxide generated in the zirconium-based chemical conversion treatment as a liquid is stored;
A sheet-like short fiber nonwoven fabric comprising a separation tank to which the treatment liquid is supplied from the waste liquid tank, and having a bubble point average pore diameter of 30 to 33 μm at a head pressure of 50 mm as a permeation performance that supports only the upper side and is suspended. The particles contained in the treatment liquid by immersing the non-woven fabric in the treatment liquid in the separation tank in a direction along the vertical direction and moving the nonwoven fabric in the front and back direction in a direction of hitting the treatment liquid on the front and back surfaces. After the solid matter is adhered to the fibers constituting the nonwoven fabric, the bubbles generated in the treatment liquid of the separation tank collide with the nonwoven fabric, and the nonwoven fabric is moved up and down with respect to the treatment liquid to perform the treatment. The solid particles separated from the liquid are precipitated as a concentrated slurry at the bottom of the separation tank, and the treatment liquid with the reduced particle solids overflowed from the separation tank. And a separation unit,
A reflux part for returning to the waste liquid tank while temporarily storing the treatment liquid that has flowed out due to the overflow of the separation part;
Piping is connected to the bottom of the separation tank, and after the treatment liquid is returned to the waste liquid tank at the reflux section for a predetermined time, the concentrated slurry discharged together with a part of the processing liquid from the bottom is stored. A slurry reservoir;
A sheet-like filter is horizontally provided at the lower part of the tank, and has a filtration chamber to which the concentrated slurry from the slurry storage tank is supplied, and is provided with an edge close to the peripheral wall of the filtration chamber above the filter. The horizontal stirring plate provided with a plurality of through holes having an opening ratio of 10 to 15% is approximately half the height in the space at a substantially intermediate position in the height direction of the space above the filter in the filtration chamber. The concentrated slurry is stirred by moving the distance up and down at a speed of 1.8 to 2.1 m / min with a stroke length, and the particle solids deposited on the filter do not rise, Using a diaphragm pump, the solid particles are dispersed in the concentrated slurry so as not to immediately settle and accumulate on the filtration surface, and the filtration chamber is not pressurized. Performing suction filtration at a pressure of 00mmHg to discharge filtered water passing through the filter to Sogaibu, a filtration separator to obtain a dehydrated cake gradually accumulated residue on the filter,
A solid-liquid separation device comprising: A treatment liquid storage step of storing in a waste liquid tank a treatment liquid containing a solid particle having a particle size of 0.1 to 10 μm containing iron hydroxide generated in the zirconium-based chemical conversion treatment as a component;
The treatment liquid is supplied from the waste liquid tank to the separation tank, and is composed of a planar short fiber nonwoven fabric having a bubble point average pore diameter of 30 to 33 μm at a water head pressure of 50 mm as a permeation performance that supports only the upper side and is suspended. The particulate solid contained in the treatment liquid by immersing the nonwoven fabric in the treatment liquid in the separation tank in a direction along the vertical direction and moving the nonwoven fabric in the direction of hitting the treatment liquid on the front and back surfaces. From the treatment liquid by causing bubbles generated in the treatment liquid of the separation tank to collide with the non-woven fabric and moving the nonwoven fabric up and down relative to the treatment liquid. The first stage where the separated solid particles are precipitated as a concentrated slurry at the bottom of the separation tank and the treatment liquid reduced in the solid particles is overflowed from the separation tank And the release process,
A treatment liquid refluxing step for returning to the waste liquid tank while temporarily storing the treatment liquid that has flowed out due to the overflow of the separation tank;
The concentrated slurry that is connected to the bottom of the separation tank and is discharged together with a part of the processing liquid from the bottom after repeating a predetermined time to return the processing liquid to the waste liquid tank in the processing liquid refluxing step. Slurry storing step for storing the slurry in a slurry storage tank;
A filtration chamber in which a sheet-like filter is horizontally provided at the lower part of the tank and the concentrated slurry is supplied from the slurry storage tank is provided with an edge close to the peripheral wall of the filtration chamber above the filter. The horizontal stirring plate provided with a plurality of through holes having an opening ratio of 10 to 15% is approximately half the height in the space at a substantially intermediate position in the height direction of the space above the filter in the filtration chamber. The concentrated slurry is stirred by moving the distance up and down at a speed of 1.8 to 2.1 m / min with a stroke length, and the particle solids deposited on the filter do not rise, Using a diaphragm pump, the solid particles are dispersed in the concentrated slurry so that they do not immediately settle and accumulate on the filtration surface, and the filtration chamber is not pressurized. Performing suction filtration at a pressure of 600mmHg was discharged to Sogaibu filtered water passing through the filter, and filtered off to obtain a dehydrated cake gradually accumulated residue on the filter,
A solid-liquid separation method comprising:

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