JPH07275608A - Solid-liquid separation apparatus - Google Patents

Abstract

PURPOSE:To produce uniform and tight granular articles in the whole region of a tank without forming a zone of granular articles with uneven granular shapes even in the case the tank diameter is wide. CONSTITUTION:Regarding a solid-liquid separation apparatus for a suspension containing metal hydroxides, cross-type or lattice-like paddle blades 5 to carry out granulation are installed in the upper part of a solid-liquid separation apparatus 1 and turbine blades 9 to generate convection up and down are installed in the lower part of the paddle blades. Further, the solid-liquid separation apparatus is the one in which acute angle parts of the puddle blades and/or the turbine blades are made round, a water passing hole is formed in the puddle blades, the puddle blades are attached to a puddle axis through flange-attached cup rings installed in the puddle axis in the way they can be detached freely, a plurality of mud discharging outlet 11 for granular articles are installed in the circumferential direction of the wall faces of the solid-liquid separation apparatus, and a mud lake is installed in the paddle axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension containing a metal hydroxide, such as zinc and nickel contained in waste water discharged from a metal surface treatment factory such as a plating factory, an electrolytic polishing factory, and an alumite factory. Caustic soda, sodium carbonate, slaked lime, to remove heavy metal ions such as aluminum, tin, etc.
The present invention relates to a solid-liquid separation device for granulating and separating a metal hydroxide from a suspension of a metal hydroxide produced by reacting a neutralizing agent such as lime.

[0002]

2. Description of the Related Art Conventionally, a precipitation separation method, a floating separation method, a filtration separation method, an adsorption separation method and the like have been known as a method for separating a suspended solid substance from a suspension containing a suspended substance. In particular, in the case of containing a metal hydroxide having a relatively large specific gravity and a large amount of waste water, for example, see pages 95 to 98 of "Solid-liquid separation technology" published by Gihodo Publishing Co., Ltd. on November 10, 1979. The precipitation method is generally used because it is the cheapest and the stable treatment can be expected.

In the case of metal hydroxide flocs produced by the reaction of metal ions such as zinc, aluminum, tin and iron with an alkaline neutralizing agent such as caustic soda or slaked lime, solid-liquid separation is difficult as it is. Therefore, a method of adding an organic polymer coagulant to increase the size of flocs to promote sedimentation is adopted.

However, the flock produced by such a method has a large apparent particle size, but the particles are loosely bound to each other, and since a large amount of water is contained inside, the density is low. No increase in sedimentation rate can be expected. Also, the concentration and dehydration are not good. In view of this, Japanese Patent Laid-Open No. 2-174992 discloses that a floc having a dense and strong binding force, which is fundamentally different from the conventional flocculation-precipitation floc, is formed, so that the flocculation rate of the conventional flocculation-precipitation method is higher than that of the flocculation-precipitation method. In addition to increasing the sedimentation speed several times, the efficiency and stability of flocculation and separation can be improved to the extent that the filtration step used as a finishing after the flocculation and precipitation, which was conventionally required, can be omitted, and the concentration and dehydration properties can be improved. A solid-liquid separation method for simultaneously producing good sludge is disclosed.

[0005]

In the apparatus used for carrying out this solid-liquid separation method, cross-shaped and lattice-shaped paddle blades are provided in the center of the tank, and the paddle blades and the flock or flock are rotated by rotating the paddle blades. They collide with each other, release the water in the floc, and make a rolling motion to form round and tight particles.

However, especially when the amount of treated water is large, the tank diameter becomes large, and the peripheral speeds at the tip and the central portion of the paddle blade are significantly different, so that it is difficult to uniformly produce a dense and tight granular material. That is, even if a tight granular material is generated in the outer peripheral portion of the tank having a high peripheral speed, it is difficult to form a compact granular material in the zone of the central portion having a low peripheral speed. Therefore, there is a concern that the light particulate matter in the central portion will roll up due to the upward flow velocity, carry over to the treated water, and deteriorate the water quality.

Therefore, an object of the present invention is to enable the formation of a uniform and high-density compacted particle throughout the tank without forming an uneven zone of the particle shape even when the tank diameter is large. A solid-liquid separator is provided.

[0008]

The above objects can be achieved by the following inventions. That is, according to the present invention, after adding an anionic polymer flocculant, a particulate solid and a cationic polymer flocculant to a suspension containing a metal hydroxide, the suspension is allowed to flow in an upward flow and In a solid-liquid separator for a suspension containing metal hydroxide that granulates and separates a suspension by stirring, a cross-shaped or grid-shaped paddle blade for granulation is placed above the solid-liquid separation tank. The solid-liquid separation device is characterized in that a turbine blade for causing up and down convection is arranged below the paddle blade, and at least one of the following (1) to (5) is provided. Use as a summary. (1) The sharp edges of the paddle blades and / or turbine blades are rounded. (2) Water holes are provided in the paddle blades. (3) The paddle blades are detachably connected by a flanged coupling provided on the paddle shaft. (4) A plurality of mud discharge ports for particulate matter are provided in the circumferential direction of the wall surface of the solid-liquid separation device. (5) A mud rake should be provided on the paddle shaft.

[0009]

According to the present invention, in the solid-liquid separation device in which the turbine blade is provided below the paddle blade, the solid-liquid separation efficiency and the solid-liquid separation efficiency and the solid-liquid separation efficiency can be improved by improving the turbine blade, the paddle blade, the mud discharge port or the mud discharge mechanism. The liquid separation operation is significantly improved.

[0010]

The present invention will be described in more detail with reference to the embodiments shown in the drawings. FIG. 1 is a diagram for explaining an outline of a solid-liquid separation device having a paddle blade and a turbine blade, in which a paddle blade stirring motor 2 and its speed reducer 3 are provided above a solid-liquid separation tank 1.
Is provided with a paddle stirring shaft 4, and a plurality of sets of cross-shaped or lattice-shaped paddle blades 5 are provided below the stirring shaft 4. Further, a turbine blade stirring motor 6 and a speed reducer 7 for the turbine blade are provided below the solid-liquid separation tank 1. A disk 12 and a turbine blade 9 are fixed to the motor 6 via a turbine blade stirring shaft 8. ing.

In the suspension which is the liquid to be treated, since the metal hydroxide in the suspension is positively charged, the action of charge neutralization and adsorptive cross-linking is caused by the addition of the anionic polymer flocculant, and the floc is blocked. Is formed. That is, at the same time as the addition of the anionic polymer flocculant, a granulated solid, for example, blast furnace water slag fine powder is added and rapidly stirred for several minutes, and the cationic polymer flocculant is added before coarse flocs are formed. As a result, the particulate solid matter is incorporated into the flocs that are being formed by the action of the anionic polymer flocculant, and forms a large number of nuclei. Further, by the action of the cationic polymer flocculant, the cationic polymer flocculant is adsorbed and crosslinked with the metal hydroxide and the particulate solid,
At the same time, it creates an anionic polymer flocculant and a complicated network structure. Since the cationic polymer flocculant has many adsorption active sites in the molecular chain, the molecular chain is entangled by gentle stirring to form a dense and dense floc having a strong bonding force.

A liquid to be treated composed of such a floc group is
The solid-liquid separation tank 1 is introduced into the separation tank 1 through an inflow port 10 provided at the bottom of the tank, stirred by a turbine blade 9 and becomes an upward flow. In the solid-liquid separation tank 1, the cross-shaped or lattice-shaped paddle blades 5 are slowly rotating, and here the paddle blades 5 and the flocks or flocs collide with each other to release the water in the flocks and roll. The movement forms a round, tight grain.

The granules thus produced have a diameter of 1 to 1.
Since it is a very fine and compact particle of 0 mm, it has a high density, and it is possible to increase the sedimentation speed as compared with the conventional flocculation-precipitation method flocs. The particulate matter formed in the solid-liquid separation tank 1 is intermittently or continuously discharged as a slurry from the slurry discharge port 11 of the solid-liquid separation 1. Concentration and dehydration of the discharged slurry are much better than those of the conventional method. On the other hand, the clear water from which the granules have been granulated and removed is the discharge port 13 provided at the upper part of the separation tank 1.
It is separated from and discharged.

The solid particles used in the above treatment include:
Basically, any material can be used as long as it is the core of floc, but in the steel industry, granulated fine powder obtained by granulating and classifying granulated slag generated as a by-product from a blast furnace has an appropriate specific gravity. However, it is highly suitable because it can be easily obtained at low cost. Especially, when granulated blast furnace fine powder with an average particle size of about 50 μm is used as a granular solid, the granulated fine powder is easily incorporated into the metal hydroxide. It becomes the core of Flock.
This water granulation has a high specific gravity of 2.9, is effective for increasing the sedimentation rate of the formed flocs, and has good concentration and dehydration properties.

As a method of stirring and flowing in the tank, the paddle blades are slowly rotated, the paddle blades and the flocs and the flocs are made to collide with each other to expel the water in the flocs, and rolling motion is caused to form round particles. The treatment method of forming and promoting dehydration is highly suitable. The paddle blade used here is, for example, one in which four flat plates are combined in a cross shape, or one in which flat plates are combined in a grid-like cross section.

In this treatment system, a great effect can be exerted by providing a compaction filtration section above the stirring flow section, that is, the section that causes turbulent flow and rolling motion in the sludge blanket zone. In other words, in the agitation flow section, the flocs collide with each other and the flocs and the blades collide repeatedly, and the dense granular particles with a strong bond strength of 1 to 10 mm formed by the rolling motion are moved upward by upward flow. Although it is extruded, if this granular material is further fixed to a portion where there is no stirring motion, solid-liquid separation occurs and an interface is formed. Clear water above the interface is discharged as treated water.

By the way, in such a solid-liquid separator as well, when the amount of treated water is large, the tank diameter becomes large, and the peripheral speeds at the tip and the center of the stirring paddle blade are significantly different. Hard to generate uniformly. That is, even if a tight granular material is formed in the outer peripheral portion of the tank having a high peripheral speed, it is difficult to form a compact granular material in the zone of the central portion having a low peripheral speed.
Therefore, the light granular material in the central portion is rolled up by the upward flow velocity and carries over to the treated water to deteriorate the water quality.

Such a problem is solved by providing a turbine blade 9 for causing up and down convection in the separation tank 1 below the paddle blade 5. The turbine blade 9 draws a floc group at the center of the tank into the lower turbine blade 9 and causes a flow to be discharged to the outer peripheral portion of the tank. Therefore, unformed granules in the zone at the center of the tank and light flocs in the middle of the granulation are prevented from rolling up by the flow drawn into the lower part, and are discharged to the outer peripheral zone of the tank so that the outer circumference is In the zone, unformed flocs are also re-granulated into high-density compacted granules. In this manner, the action of vertical convection by the lower turbine blades 9 results in the formation of uniformly compacted particles in the tank.

The turbine blade 9 also has a function of uniformly dispersing the liquid to be treated (suspension) supplied from the bottom of the tank in an upward flow in the tank. That is, when the tank diameter increases as the amount of treated water increases, it is difficult to evenly supply the liquid to be treated supplied from the bottom to the entire area of the tank. However, by installing the turbine blade 9 in the lower part, the liquid to be treated supplied from the bottom once hits the disk plate 12 of the turbine blade 9, and is made uniform around the tank by the rotation of the turbine blade 9. . The dispersed liquid to be treated rises in the tank as a uniform upward flow, causing upper and lower convection.

The rotation speed of the turbine blade 9 is S in the zone.
Although it depends on the S property and the SS concentration, it is necessary to rotate in the range of 1 to 50 rpm in order to cause up and down convection.
On the other hand, the number of rotations of the paddle blade for granulation varies depending on the water quality of the liquid to be treated, the SS property and SS concentration in the zone,
The range is 0.1 to 5 rpm. Therefore, the two types of different rotary blades can rotate at different rotational speeds.

FIG. 2 is a diagram for explaining an embodiment of the improved device of the present invention, which is an example in which the acute-angled portion of the turbine blade 9 shown in FIG. 1 is rounded. FIG. 2A is an enlarged view of the disk-type turbine blade 9, and FIGS. 2B to 2D show a state 15 in which sharp corners of the turbine blade 9 fixed to the disk 12 are rounded.
Is shown. By rounding off the acute-angled portions of the turbine blade 9 in this manner, the chances that the acute-angled portions of the turbine blade 9 break the particulate matter once generated during granulation are reduced.

FIG. 3 is a diagram for explaining another embodiment of the present invention, in which the paddle blade 5 shown in FIG. 1 is provided with a cavity portion (water passage hole) 16 through which the liquid to be treated can pass. Here is an example. Also in this example, by rounding the acute-angled portion of the paddle blade 5, it is possible to reduce the amount of the granules adhering to the paddle blade, and the granular material once generated at the time of granulation of the paddle blade 5 The chance of breaking the sharp corner is further reduced.

FIG. 4 is a view for explaining another embodiment of the present invention, showing a connected state of the paddle rotating shaft 4 and the paddle blades 5 shown in FIG. A coupling 17 with a flange is provided on the paddle shaft 4, and a flange provided on an end of the paddle blade 5 is detachably attached to the flange of the coupling 17 by a conventional connecting means. The coupling 17 is coaxial with the paddle rotation shaft 4 and is vertically slidable. With such a configuration,
It becomes easy to replace the paddle blades, change the interval between the paddle blades, maintain the paddle blades, etc., and appropriately respond to changes in the properties of the liquid to be treated.

FIG. 5 is a diagram for explaining another embodiment of the present invention, in which the sludge discharge port 11 provided in the solid-liquid separation tank 1 shown in FIG.
Regarding the improvement of. As shown in the figure, by providing a plurality of sludge discharge ports 11 at the outer peripheral portion of the paddle blade in the solid-liquid separation tank 1 where the concentration of the particulate matter is high, preferably at equal intervals, the sludge of the particulate matter is made efficient. By further connecting the sludge collecting pipes 18 around the plurality of sludge discharge ports 11, the sludge discharged can be collected in one place and discharged to the outside of the system.

FIG. 6 is a view for explaining another embodiment of the present invention, which relates to the improvement of the sludge discharge mechanism shown in FIG. As shown in the figure, a particulate matter concentration region 19 is provided below the turbine blade 9 in the solid-liquid separation tank 1, and the tip of the liquid inlet 10 to be treated is connected to the turbine blade 9
A mud collecting rake 20 that is opened immediately below and is connected and rotated below the paddle rotation shaft 4 is provided. By doing so, the granular material granulated in the solid-liquid separation tank 1 settles at the bottom of the granular material concentration region 17, and is collected in the central portion of the tank bottom by the mud collecting rake 20 to form a high-concentration slurry. Is discharged.

Next, an example of using the device of the present invention will be described. The apparatus of FIG. 1 with the modification of FIG. 2 is used. The pH of the waste liquid containing zinc ions 300 mg / liter and iron ions 90 mg / liter generated from the electrogalvanizing plant is adjusted to 1 with slaked lime.
To the suspension containing the metal hydroxide formed by neutralization to 1, the polyacrylamide anionic polymer flocculant was added at 4 mg / liter, and the granulated blast furnace slag having an average particle size of 50 μm was added at 300 mg / liter. Rapidly stir for 5 minutes, and then 2 mg of polyacrylamide-based cationic polymer flocculant 4
/ Liter was added, and the solid-liquid separation tank 1 was caused to flow in an upward flow.

In the solid-liquid separation tank 1, a cross-shaped paddle blade 5 was installed at the upper part and rotated at 3 rpm, and a turbine blade 9 was installed at the lower part and rotated at 10 rpm. The solid-liquid separation tank 1 is
A column made of vinyl chloride resin having a column diameter of 500 mm and a height of 2000 mm was used.

The flocs flowing into the solid-liquid separation tank 1 undergo a dehydration phenomenon and a rolling motion in the column, so that the flocs are 1 to 10 mm.
It became a pellet-shaped dense granular material. In addition, a sludge blanket zone was created above the paddle wings. In this sludge blanket zone, it was possible to obtain an OFR of 13 m / Hr.

The clarified water which was solid-liquid separated was discharged from the upper part, and became very good treated water with SS 3 mg / liter and zinc ion 0.1 mg / liter. Further, at this time, in the solid-liquid separation tank, granular particles that were uniformly tightened in the tank by the action of turbine blades were formed.

[0030]

According to the present invention as described above, in the present invention, in the solid-liquid separation device in which the turbine blade is provided under the paddle blade, the turbine blade, the paddle blade, the mud discharge port or the mud discharging mechanism is provided. By improving, the solid-liquid separation efficiency and the solid-liquid separation operation are significantly improved.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an outline of an apparatus before improvement.

FIG. 2 is a diagram showing an embodiment of an improved device of the present invention.

FIG. 3 is a diagram showing another embodiment of the improved device of the present invention.

FIG. 4 is a diagram showing another embodiment of the improved device of the present invention.

FIG. 5 is a diagram showing another embodiment of the improved device of the present invention.

FIG. 6 is a diagram showing another embodiment of the improved device of the present invention.

[Explanation of symbols]

 1 solid-liquid separation tank 2 motor 3 reducer 4 paddle blade rotating shaft 5 paddle blade 6 motor 7 reducer 8 turbine blade rotating shaft 9 turbine blade 10 inlet 11 mud outlet 12 disk 13 drain outlet 14 coupling 15 corner deletion Part 16 Cavity part 17 Coupling 18 Sludge collecting pipe 19 Concentrate of particulate matter 20 Rake

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 18, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

In the suspension which is the liquid to be treated, since the metal hydroxide in the suspension is positively charged, the action of charge neutralization and adsorptive cross-linking is caused by the addition of the anionic polymer flocculant, and the floc is blocked. Is formed. That is, simultaneously with the addition of the anionic polymer flocculant, a granulated solid, for example, granulated blast furnace fine powder is added and rapidly stirred for several minutes, and the cationic polymer flocculant is added before coarse flocs are formed. As a result, the particulate solid matter is incorporated into the flocs that are being formed by the action of the anionic polymer flocculant, and forms a large number of nuclei. Further, by the action of the cationic polymer flocculant, the cationic polymer flocculant is adsorbed and crosslinked with the metal hydroxide and the particulate solid,
At the same time, it creates an anionic polymer flocculant and a complicated network structure. Since the cationic polymer flocculant has many adsorption active sites in the molecular chain, the molecular chain is entangled by gentle stirring to form a dense and dense floc having a strong bonding force.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

The granules thus produced have a diameter of 1 to 1.
Since it is a very fine and compact particle of 0 mm, it has a high density, and it is possible to increase the sedimentation speed as compared with the conventional flocculation-precipitation method flocs. Also, granules which are formed by solid-liquid separation tank 1 is a slurry of the solid-liquid separation 1 slurry
-It is discharged from the sludge discharge port 11 intermittently or continuously. Concentration and dehydration of the discharged slurry are much better than those of the conventional method. On the other hand, the clear water from which granules have been granulated and removed is the drain port 13 provided at the upper part of the separation tank 1.
It is separated from and discharged.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

The solid particles used in the above treatment include:
Basically, any material can be used as long as it is the core of flocs, but in the steel industry, granulated fine powder obtained by crushing and classifying granulated slag generated as a by-product from the blast furnace has an appropriate specific gravity. It is highly suitable because it can be easily obtained at low cost. Especially, when granulated blast furnace fine powder with an average particle size of about 50 μm is used as granular solid, this granulated fine powder is easily incorporated into the metal hydroxide. Becomes the core of Flock.
This water granulation has a high specific gravity of 2.9, is effective for increasing the sedimentation rate of the formed flocs, and has good concentration and dehydration properties.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of symbols] 1 solid-liquid separation tank 2 motor 3 reducer 4 paddle blade rotating shaft 5 paddle blade 6 motor 7 reducer 8 turbine blade rotating shaft 9 turbine blade 10 inlet 11 drainage port 12 disk 13 drainage port 14 cup Ring 15 Corner removal part 16 Cavity part 17 Coupling 18 Sludge collecting pipe 19 Concentrate of particulate matter 20 Rake

[Procedure correction 6]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhisa Fukunaga 20-1 Shintomi, Futtsu City, Chiba Shin Nippon Steel Co., Ltd. Corporate Technology Development Division (72) Inventor Akira Ito 1 Kimitsu, Kimitsu City, Chiba New Nippon Steel Stock Company Kimitsu Works (72) Inventor Toshio Shimooka 2-5-12 Higashi-Kanda, Chiyoda-ku, Tokyo Environmental Engineering Co., Ltd. (72) Hiroyuki Kashiwara 2-5-12 Higashi-Kanda, Chiyoda-ku, Tokyo Environment Inside Engineering Co., Ltd. (72) Inventor Naofumi Yamachi 2-5-12 Higashikanda, Chiyoda-ku, Tokyo Inside Environmental Engineering Co., Ltd.

Claims (5)

[Claims] 1. An anionic polymer flocculant, a granular solid, and a cationic polymer flocculant are added to a suspension containing a metal hydroxide, and then the suspension is flown in and stirred in an upward flow. In a solid-liquid separation device for a suspension containing a metal hydroxide that granulates and separates a suspended material by disposing a cross-shaped or lattice-shaped paddle blade for granulation in the upper part of the solid-liquid separation tank. The solid-liquid separation device is characterized in that a turbine blade for causing up and down convection is arranged below the paddle blade, and an acute angle portion of the paddle blade and / or the turbine blade is rounded. 2. An anionic polymer flocculant, a granular solid and a cationic polymer flocculant are added to a suspension containing a metal hydroxide, and then the suspension is flown in and stirred in an upward flow. In a solid-liquid separator for a suspension containing a metal hydroxide that granulates and separates the suspended solids, a cross-shaped or lattice-shaped paddle blade for granulating is placed above the solid-liquid separation tank. A solid-liquid separation device characterized in that a turbine blade for causing up and down convection is arranged below the paddle blade, and a water passage hole is provided in the paddle blade. 3. An anionic polymer flocculant, a granular solid and a cationic polymer flocculant are added to a suspension containing a metal hydroxide, and then the suspension is flown in and stirred in an upward flow. In a solid-liquid separation device for a suspension containing a metal hydroxide that granulates and separates a suspended material by disposing a cross-shaped or lattice-shaped paddle blade for granulation in the upper part of the solid-liquid separation tank. A turbine blade for causing up and down convection is arranged below the paddle blade, and the paddle blade is detachably connected by a flanged coupling provided on the paddle shaft. Liquid separator. 4. An anionic polymer flocculant, a granular solid, and a cationic polymer flocculant are added to a suspension containing a metal hydroxide, and then the suspension is flown up and stirred. In a solid-liquid separation device for a suspension containing a metal hydroxide that granulates and separates a suspended material by disposing a cross-shaped or lattice-shaped paddle blade for granulation in the upper part of the solid-liquid separation tank. , Characterized in that a turbine blade for causing vertical convection is arranged below the paddle blade, and a plurality of mud discharge ports for particulate matter are provided in a wall circumferential direction of the solid-liquid separator. Solid-liquid separation device. 5. An anionic polymer flocculant, a granular solid and a cationic polymer flocculant are added to a suspension containing a metal hydroxide, and then the suspension is flown in and stirred in an upward flow. In a solid-liquid separation device for a suspension containing a metal hydroxide that granulates and separates a suspended material by disposing a cross-shaped or lattice-shaped paddle blade for granulation in the upper part of the solid-liquid separation tank. A solid-liquid separation device characterized in that a turbine blade for causing up and down convection is arranged below the paddle blade, and a mud collecting rake is provided on the paddle shaft.