JP2814417B2 - Method and apparatus for sedimentation and separation of suspension - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heavy liquid (sedimentation concentrate) having a high concentration of suspended solids (suspended particles) by using a sedimentation tank.
More specifically, the present invention relates to a method and apparatus for sedimentation and separation of a suspension which is separated into a light liquid having a low concentration of suspended solids, and more particularly to a method for continuously suspending particles without depositing suspended particles on the bottom of a sedimentation tank. The present invention relates to a method and apparatus for sedimentation and separation of a suspension that can be separated and classified.

[0002]

2. Description of the Related Art Conventionally, means for separating suspended particles (suspension) contained in a suspension include, for example, a sedimentation tank (including a sedimentation pond), a drag belt classifier, a thickener concentrator, and the like.
A centrifuge, a wet cyclone separator, and the like are known. However, conventional suspension separation means include, for example, that suspended particles are easily deposited on the bottom of a settling tank, separation and classification of a fine particle region are difficult, unsuitable for upsizing, or operation costs are high. Therefore, there is a need for improvement.

On the other hand, the inventor of the present invention applied a centripetal force field by a method of generating a stable swirling flow without causing a short-circuit flow from the liquid surface when the suspension was settled and separated using a settling tank. , By the simultaneous addition of a gravitational field to the suspension,
It was discovered that the suspension could be continuously separated and classified into a heavy liquid with a high concentration of suspended matter and a light liquid with a low concentration of the suspended substance without depositing suspended particles on the bottom of the sedimentation tank. (Japanese Patent Application No. 3-149747, Japanese Patent Application No. 4-204)
No. 46).

That is, in the suspension sedimentation / separation apparatus proposed by the present inventor, the suspension is introduced into the sedimentation tank, the suspended matter is sedimented by gravity, and the suspension is collected at the lower part of the sedimentation tank. The liquid is returned to the lower part of the original settling tank to generate a laminar swirling flow, so that separation and classification can be performed more effectively without depositing suspended matter on the bottom. . However, when the sedimentation separation device is operated for a long time using a suspension containing coarse particles as a liquid to be treated, the sedimentation separation device is installed at a branch point of a pipe (circuit, conduit) for refluxing the suspension at a branch point lower than the branch point. The sedimentation and deposition of suspended particles may occur. Therefore, when a suspension having a miscellaneous particle size composition (for example, industrial waste liquid) is used as the liquid to be treated, the circuit of the device is blocked, and the There is a problem that stable processing is difficult.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sedimentation separation apparatus using both a gravitational field and a centripetal force field.
An object of the present invention is to provide a sedimentation / separation device that prevents the clogging of the device due to sedimentation of coarse particles ranging from 00 μm to 2 mm, and operates stably for a long period of time.

As a result of intensive studies, the present inventor has found that in a sedimentation separation apparatus using both a gravitational field and a centripetal force field,
In generating and maintaining a swirling flow that does not short-circuit with the liquid surface,
The sediment concentrate (suspension at the bottom) collected by the pump means is branched into an upward circuit and a downward circuit, and the upward circuit liquid is returned to the original sedimentation separation layer to be the driving force of the swirling flow. It has been found that the suspension can be continuously separated and classified by preventing the clogging of the circuit by configuring to collect the sedimentation concentrate from the circuit, and based on the knowledge, the present invention has been completed. Was.

[0007]

Thus, according to the present invention, the suspension collected by the pump means from the center of the bottom of the suspension settling tank is branched into an upward circuit and a downward circuit, and The suspension branched into the circuit is returned to the bottom of the sedimentation tank to generate and maintain a swirling flow that does not cause a short-circuit flow from the liquid level to the bottom of the suspension in the tank. A method for settling and separating a suspension is provided, wherein a heavy solution having a high concentration is collected.

Further, according to the present invention, there is provided a sedimentation tank for introducing a suspension and separating the suspension into a heavy liquid having a high concentration of suspended matter and a light liquid having a low concentration of suspended matter. Pump means for collecting the suspension from the center of the bottom of (b), (b) a conduit for guiding the suspension collected by the pump means to a branching device,
(C) a branching device for branching the suspension flowing from the conduit into an upward circuit and a downward circuit, (d) a return circuit for refluxing the suspension branched into the upward circuit to a settling tank, And (e) providing an outlet for a return circuit around the bottom of the settling tank,
Using the flow of the suspension discharged from the discharge port of the return circuit as a driving force, a swirling flow that does not cause a short-circuit flow from the liquid level of the suspension in the tank to the bottom is generated and maintained. An apparatus for settling and separating a suspension is provided, which is configured to collect a liquid.

Hereinafter, the present invention will be described in detail. (Suspension) The suspension which is the liquid to be treated in the present invention is usually a liquid in which water is used as a medium and particles are suspended as a medium. As the medium, an aqueous liquid whose specific gravity is adjusted by adding a solvent compatible with water such as alcohol may be used.
Further, a suspension in which oil is used as a suspension medium and water is dispersed therein can also be treated.

[0010] The size of the suspended particles targeted by the present invention is:
All particles having an upper limit of about 2 mm which can be transferred by a pump. Particles exceeding 2 mm are called gravels and can be easily separated by filtration through a mesh sieve, so that there is no need to apply the method and apparatus of the present invention.

[0011] The suspended particles targeted by the present invention may have any shape, and may be any of organic, inorganic, natural, synthetic and chemical compositions. For example, fine particles in industrial waste and dust, kaolin, pyrophyllite,
Various types of particles such as clay minerals such as talc, organic polymer fine particles such as ion-exchange resin powder, microorganisms such as yeast, and chemical reaction products such as polymers.

(Sedimentation tank) As the sedimentation tank used in the present invention, in addition to the ordinary suspension sedimentation tank, a chemical reaction tank, a washing tank,
Various tanks such as relay and storage tanks can be used. Chemical reactions include heterogeneous chemical reactions such as solids and liquids, suspension polymerization of organic polymers, electrolysis to generate a suspension, electrolytic reactions such as electrodeposition coating using a suspension, and fermentation. Biochemical reactions such as culture can be mentioned. In addition, as a reaction tank in a broad sense, a breeding tank, a fish tank, an appreciation tank, and the like for fish whose suspension is to be prevented can be applied.

[0013] As the washing tank, washing and drainage treatment tanks for mineral products such as metal ore, coal, limestone, silica stone, stone materials, pottery stones, etc .; treatment tanks for powder suspensions obtained by grinding; ion exchange resins; Purification tank for suspension of synthetic polymer resin particles used in powder coatings and toners; suspension of various mixed powders such as metal pieces, plastic pieces, concrete pieces, crushed stone powder, coal ash, various ash, earth and sand, and dust Suspension treatment tank; cleaning tank for cleaning surfaces of various objects such as chemical etching treatment tank for metal surface, metal surface treatment tank, bathtub, etc .;

The relay / storage tank includes a water storage tank, a water supply tank,
A liquid storage tank, a liquid supply tank, and the like are included. For example, in the chemical industry field, tanks for relaying the reaction process and storing raw materials and products are provided at various places, but stirring is performed so that sedimentary sediment does not occur during storage, and the generated sediment is removed. Or need to. The method and apparatus of the present invention are suitable for those fields where it is desired to prevent such sedimentation. Further, the method and apparatus of the present invention can be used for dams, lakes, ponds, and the like for removing sediment and the like.

(Method and Apparatus for Sedimentation and Separation of Suspension) Hereinafter, the method and apparatus of the present invention will be described with reference to specific examples. FIG. 1 is a schematic sectional view showing an example of a sedimentation separation device used in the present invention. In the apparatus of FIG. 1, the suspension to be treated (12) is introduced into the settling tank (1) from the liquid supply discharge port (23). The suspension sediments suspended particles in a settling tank and separates the suspension into a heavy liquid with a high concentration of suspended solids (sedimentation concentrate) and a light liquid with a low concentration of suspended solids. The light liquid is collected by overflowing by an overflow means such as an overflow weir (24) provided in the upper part of the sedimentation tank. In the case of the light liquid from which suspended matter has been sufficiently removed, fresh water is used. It is possible to collect as. In the method and apparatus of the present invention, suspended particles can be settled and classified based on the Stokes settling equation. For example, if a suspension containing clay particles is introduced into a sedimentation tank and treated for a predetermined time, the light liquid is overflowed and collected, whereby particles having a predetermined particle size contained in the light liquid can be obtained.

The bottom shape of the sedimentation tank (1) may be flat, but in practice, a cone shape is preferable even if the inclination is gentle. A conventional chemical reaction tank, storage tank, relay tank, or the like may be used. A part of a water tank such as an irregular pond, lake, or dam may be used. At the center of the bottom of the settling tank (1),
A submersible pump (2) with a structure that prevents direct inflow from above is installed. The liquid discharged from the pump is led from the conduit (3) to the branching device (4), and is branched into an upward circuit (5) and a downward circuit (6). The upward circuit (5) and the downward circuit (6) can use vertical tubes. Conduit (3)
Are usually arranged to flow horizontally into a vertical tube, as shown in FIG. Although a cheese (three-way pipe joint) can be used for the branching device (4), it is preferable to use a deformed cheese having a larger diameter in the vertical direction than a cheese having the same diameter in three directions. The pipe used for the upward circuit (5) is preferably long and high. Further, a cyclone classifier or a centrifugal separator can be used as the branching device (4).

The reason why the suspension was collected by the pump means at the center of the bottom of the sedimentation tank is to collect the sediment concentrate (heavy liquid). The purpose of preventing the inflow of short-circuit is to prevent the occurrence of short-circuit flow from the liquid level in the sedimentation tank and the inability to separate and classify suspended particles. In the submersible pump (2) shown in FIG. 1, the suction port is provided on the lower side surface of the pump, thereby preventing the occurrence of a short-circuit flow.

In the branching device (4), the sedimentable coarse particles in the suspension are distributed more but less in the lower circuit (6) than in the upper circuit (5). In particular, if a cyclone classifier is used as the branching device (4), the coarse particles can be more efficiently distributed to the downward circuit (6). By branching the suspension into the upper circuit and the lower circuit, coarse particles having a particle size of 75 μm or more can be separated from the lower circuit, and the clogging of the piping can be prevented.

The upward circuit (5) includes a flow control valve (7)
The suspension is allowed to flow into the return circuit (10) while adjusting the flow rate with the provision of (1). The leading end of the return circuit (10) is guided to the periphery of the bottom in the settling tank (1) to form a discharge port (11), and discharges the suspension to form a swirling flow. The discharge direction of the discharge port (11) is usually arranged such that the suspension is discharged along the inner wall of the settling tank (1). In this way, the suspension (sedimentation concentrated liquid) collected from the center of the bottom of the settling tank is refluxed, and discharged from the periphery of the bottom into the tank, thereby generating a swirling flow in the suspension in the settling tank. , Let me maintain. In order to prevent a tornado-like short-circuit flow from the liquid level in the sedimentation tank due to this swirling flow, the amount of liquid collected by the submersible pump is adjusted, and the amount of reflux is adjusted by the flow control valves (7) and (8). I do. When the suspended particles are large, the recirculation amount is adjusted so that the swirling flow is set strong, and when the suspended particles are fine, the swirling flow is set weakly. Also,
When the sedimentation tank is large, it is preferable to provide a plurality of discharge ports (11) so that the swirling flow can be smoothly generated and maintained.

When the swirling flow is generated and maintained, the centripetal acceleration overlaps with the gravitational field, and the suspended particles can be selectively and continuously settled at the bottom center of the settling tank and concentrated. That is, the suspended particles gather and concentrate at the center of the centripetal force field while settling. The settling acceleration of the suspended particles follows the Stokes settling equation. When the suspension is refluxed to generate and maintain a swirling flow, even if the suspended particles are concentrated at the bottom, they do not accumulate because they remain in a fluid state. In the case of fresh water, the swirling flow gradually and gradually spreads to the liquid surface, but in the case of a suspension, the viscosity and specific gravity of the suspension are larger than that of water, so that the swirling flow of the suspension hardly spreads to the liquid surface.

The sediment concentrate is collected by a submersible pump, at least a part of which is returned to the original tank, and
A portion is taken from the down circuit (6). The downward circuit (6) includes a flow control valve (8), and controls the collection flow rate of the sedimentation concentrate. The collected sedimentation concentrate is led to a post-processing device (9) such as a dewatering device.

The suspension to be treated may be directly introduced into the settling tank, but may be pretreated or coarse particles may be separated in advance. For example, as shown in FIG. 1, the suspension to be treated (12) is guided to a pretreatment device (13), and filtration, dialysis or ion exchange treatment is performed. The suspension is then led to a branching device (14), where an upward circuit (19) and a downward circuit (1) are provided.
Branch to 5). The upward circuit is provided with a flow control valve (18) to adjust the flow rate, and discharges from a discharge port (23) in a direction forming a swirling flow at a substantially intermediate position of the settling tank (1). The downward circuit (15) is provided with a flow control valve (16) to adjust the flow rate, and is returned to the original state through a restoration circuit.
The downward circuit (15) serves as a bypass circuit for adjusting the flow rate of the suspension to be supplied to the settling tank (1).

When washing, chemical reaction, etc. are performed in the settling tank (1), necessary developing liquid, diluting liquid, reaction liquid, gas, etc. are supplied from the injection liquid tank (27) through the discharge port (28). Discharge. Alternatively, an injection liquid introduction circuit (20) is separately provided in the middle of the pipe reaching the discharge port (23). The discharge port (28) is preferably disposed at a substantially intermediate position of the settling tank, and discharges the injection liquid or the like in a direction contributing to the formation of the swirling flow.

The effective floor area of the settling tank (1), the injection amount of the liquid to be treated, and the collection amount from the downward circuit (6) are adjusted so that an excess liquid (light liquid) overflows the overflow weir (24). Designed to be more discharged. The overflow means is arbitrary such as a circular weir, an overflow pipe, a float provided with an overflow port and a conduit. The collected liquid from the overflow weir (24) can be connected to a processing device such as an ion exchange process and an ultrafiltration.

FIG. 2 is a schematic sectional view showing an example of another apparatus of the present invention. In FIG. 2, instead of the submersible pump in FIG. 1, a baffle plate (29) is arranged at the bottom, and the sediment concentrate is collected by an external pump (31) and injected into the branching device (4). . By disposing the baffle, short-circuit inflow from the liquid level is prevented. Instead of the submersible pump or the baffle plate, a pipe having a downwardly opened sampling port may be arranged at the center of the bottom, and suction may be performed by an external pump.

A flow control valve is usually arranged in each of the upper circuit and the lower circuit. Each flow control valve is adjusted by adjusting the discharge amount of the pump means or the size of each circuit (pipe). The flow rate of the circuit may be controlled, in which case
The flow control valve is not always necessary. Further, the flow control valve may be provided only in one of the circuits.

The device of the present invention can be used by arranging a plurality of devices in series as shown in FIGS. FIG. 3 (Example of collection of suspension medium liquid from suspension) FIG. 3 shows an example in which the sedimentation / separation device having the basic configuration shown in FIG. 2 is combined. Overflow of the settling tank (301)
45) into the settling tank (302), and similarly, the overflow of the settling tank (302) is set in the settling tank (303) and the settling tank (3).
The overflow of 03) is injected into the settling tank (304), respectively. From the overflow means (346) of the settling tank (304), a clean medium liquid can be collected, and from the bottom of the settling tank (301), a concentrated suspension can be collected. The suspension is pumped from the bottom of each tank by a pump means, and each branching device (312, 31)
(3, 314) to branch into an upward circuit and a downward circuit, and discharge the upward circuit liquid to the bottom of the original tank to generate a driving force for the swirling flow, and the downward circuit liquid to the bottom of the previous tank. And preferably one of the driving forces of the swirling flow,
Increase the efficiency of separation between suspension and suspension medium. Reversing the branching not only reduces the separation efficiency, but also results in the deposition of relatively large particles at the bottom of each vessel during long term operation.

The apparatus shown in FIG. 3 can be used in an urban water supply water production plant. In the production of city water supply water, a sulfuric acid band is introduced into a rapid stirring pond, and fresh water is collected through a slow stirring pond and a sedimentation pond. Injection port (3
Raw water is injected from 20), and sulfuric acid band water is injected from the upper left injection port (330). The sedimentation tank (301) corresponds to a chemical reaction tank between the fine suspended matter and colloid particles in the raw water and the sulfate band. The settling tank (304) functions as a filtration tank and also serves as a water storage tank. Settling tank (3
04) Fresh water is collected from the overflow means (346).
The number of devices (sedimentation tanks and the like) connected in series can be appropriately determined according to the quality of the liquid to be treated. In addition, the fresh water from the overflow means (346) is guided to another relay tank or a water storage tank having a branching device, and the downward circuit liquid of the branching device is discharged to discharge a small amount of suspended matter such as rust. You may make it. In this case, it is preferable to use a wet cyclone as a branching device to adjust the amount of discharged water. In addition, the sedimentation / separation operation only under natural conditions can be performed without adding a chemical solution.

On the other hand, the settling mud (heavy liquid) in each settling tank is sent to the preceding settling tank, and thick mud can be collected from the bottom of the settling tank (301) by a pump. This thick mud,
The cake is dehydrated with a filter press. This device does not cause suspended solids to accumulate at the bottom of each tank even during long-term operation.

FIG. 4 (Collection of Suspended Matter from Suspension) FIG. 4 shows a combination of the sedimentation / separation apparatus having the basic structure shown in FIG. The concentrated liquid (heavy liquid) in the settling tank (401) is injected into the settling tank (402) via the branching device (411) and the downward circuit (452). Further, if necessary, another basic device may be connected in series in an appropriate number, and the concentration may be repeated. The concentrated liquid in the settling tank (402)
From the downward circuit of the branching device (412), the drainage device (42)
0) and settled tank (4) from the medium liquid outlet (421).
02), and the concentrated suspension is removed from the collection port (422).

The apparatus shown in FIG. 4 is suitable for collecting suspended solids from a suspension. An example of collecting resources from seawater will be described below. Seawater is injected from the inlet (430) at the left end of FIG. 4, and milk of lime is injected from the inlet (440). When lime milk is added to seawater to make it alkaline, magnesium hydroxide precipitates and becomes a suspension. The suspension is discharged from the discharge port (450) to the settling tank (401) to generate a swirling flow. The clean seawater from which the suspended solids have settled is returned to the sea from the overflow (460). The concentrate in the settling tank (401) is injected into the settling tank (402) through the branching device (411) and the downward circuit (452), and the overflow of the settling tank (402) is returned to the settling tank (401). The magnesium hydroxide suspension collected from the collection port (422) is further washed and concentrated, dehydrated, and dried to obtain a final product.

Conventionally, in order to concentrate magnesium having a content of 1% or less in seawater, a vast thickener device equipped with a scraping machine has been used. However, in order to promote the precipitation of magnesium hydroxide, The use of lime tended to be excessive and calcium was mixed in the product. On the other hand, in the apparatus of the present invention, the sedimentation separation operation is repeated in the sedimentation tank (402), and the sedimentation concentrate can be stored, so that the precipitation reaction of magnesium hydroxide can be appropriately adjusted. Further, by controlling the strength and temperature of the swirling flow, the particle diameter can be made uniform. in this way,
The device of the present invention can also be used as a chemical reaction device. It can also be used to recover resources contained in seawater other than calcium hydroxide.

FIG. 5 (Example of Classification of Suspended Particles) FIG. 5 shows a combination of the sedimentation / separation apparatus having the basic structure shown in FIG. The overflow of the settling tank (501) is injected into the middle of the settling tank (502), and the overflow of the settling tank (502) is injected into the middle of the settling tank (503). If necessary, an appropriate number of additional settling tanks are connected in series, and this operation is repeated.

The concentrated liquid in the settling tank (501) is separated from the branching device (5).
11) and through the downward circuit (537), it is poured into a dewatering device (521) such as a vertical centrifuge, and the suspended solid is taken out as a product from the sampling port (531). Collect in the dissolution tank (540). The liquid in which the powder is suspended is guided to the relay tank (550) and injected into the settling tank (501). When the injection flow rate and the floor area of the sedimentation tank are controlled, particles having a predetermined particle size or more are settled and captured in the sedimentation tank (501). The supplemented particles can be collected as a product from the collection port (531) via the branching device (511) and the liquid removing device (521). The overflow of the sedimentation tank (501) is injected into the middle of the sedimentation tank (502) having a larger floor area, and the sedimentation and separation treatment allows particles having a uniform particle size to be collected as a product (532). The same operation is performed in the settling tanks (502) and (503).
The smaller particles are obtained as a product from the sampling port (533). Settling tank (503)
Shimizu overflows from the overflow outlet (560). In addition, if the number of sedimentation tanks is increased, particles having a small particle size are sequentially obtained.
The distribution of the suspension by the branching devices (511, 512, 513) improves the efficiency of concentration and separation of suspended particles. If the branch is upside down, after long-term operation, a relatively large accumulation of particles will occur in each settling tank.

An example in which the apparatus of FIG. 5 is used for quarrying and processing of quarry powder is shown. The particles (562) of the size of the gravels and coarse sand are removed from the washing device (561) by the sieving operation (561).
Washing is performed in step 0), and the washed gravels (563) are taken out. The drainage is led to the relay tank (550), and the washed coarse sand (551)
Take out. By treating the suspension as described above, sand having a uniform particle size is collected from the concentrated liquid in the settling tank (501) through the collection port (531), and finer sand is further collected in the settling tank (502). Of the dehydrated cake of silt clay fine particles was collected from the concentrated solution of
The sample is collected from the concentrated solution of 3) through the sampling port (533). The apparatus shown in FIG. 5 can be used in many fields such as classification of mineral particles, treatment of washing wastewater, treatment of powder and dust.

In the present invention, a particle size of 5
A suspension having a predetermined particle size can be collected from the overflow port of the sedimentation separation tank by containing clay particles having a particle size of μm or less at a certain concentration in the range of 5% by weight. Fine particles having a particle size of 5 μm or less have a large specific surface area and a high surface activity. Therefore, when suspended in water, the suspension has viscosity due to affinity with water, and the specific gravity of the suspension increases. Therefore, in the suspension containing the clay fine particles, the coarse particles are easily suspended, and the stability of the suspension is increased. In the method and apparatus of the present invention, when transferring a suspension containing coarse particles, it is possible to perform a closed system treatment using recovered water in which clay fine particles are left from fresh water.

[0037]

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

Example 1 Classification of Suspension Kaolin ore was pulverized in an aqueous solution of water glass to prepare a suspension, and the coarse sand and fine sand components were removed using the method and apparatus of the present invention. Separation by settling was performed, and a suspension containing clay mineral fine particles was collected. When the suspension containing the clay mineral fine particles is made acidic, the fine particles aggregate, so that the cake is dehydrated to obtain a cake, and the cake can be further pulverized to a powder.

A suspension obtained by crushing ore in a water glass aqueous solution was introduced into the settling tank (1) from the discharge port (23) of the apparatus shown in FIG. By driving the pump (31), the suspension was led through the gap of the baffle (29) to the conduit (30) and then to the conduit (32), and was injected horizontally into the branching device (4). The injected suspension is branched into an upward circuit (5) and a downward circuit (6), and the suspension in the upward circuit is discharged from a discharge port (11) to a peripheral direction through a return circuit (10). Then, a swirling flow was generated and maintained.

By adjusting the flow regulating valves (7) and (8), a swirling flow is created around the bottom zone of the settling tank,
The short circuit flow from the liquid surface was prevented from occurring. Since the surface of the suspension in the settling tank (1) hardly flows, sedimentation of suspended particles due to gravity occurs without any trouble, and the concentrated liquid collects at the bottom. In the downward circuit below the branching device, a sedimentation concentrate having a high sedimentation velocity and containing fine sand components having a large particle diameter and a large specific gravity is extracted through a flow control valve (8) and a post-treatment device (9). Was done.

When a new suspension was introduced from the liquid supply discharge port (23), a suspension containing clay mineral fine particles could be continuously collected from the overflow weir (24). By adjusting the flow rate of the new suspension and the flow control valves (7) and (8),
When the overflow was adjusted, the operation could be performed without causing the fine sand component to overflow and without accumulating the fine sand component at the bottom of the settling tank.

When a coarse sand component is contained in the suspension to be newly supplied to the settling tank, the coarse sand component is removed by filtration with a filtration device (13), and then the suspension is guided to a branching device (14). ,
Branch into an upper circuit (19) and a lower circuit (15),
If the suspension from the upward circuit (19) is introduced into the settling tank, coarse sand and fine sand can be separated more effectively.

In this embodiment, as the branching devices (4) and (14), a piping material called cheese for connecting a pipe to a vertical pipe from a horizontal direction was used. A thin horizontal pipe was tangentially connected to a thick vertical pipe to form a branching device.

Example 2 Concentration and Separation of Suspended Substance A suspension containing clay mineral fine particles collected from the overflow weir (24) of Example 1 was used to separate suspended matter. When the suspension is made acidic, the fine particles aggregate and separate into a concentrated suspension and clean water. Therefore, this separation operation is p
It is related to the chemical reaction of H adjustment and sedimentation.

A square settling pond having a width of 5 m and a depth of 4 m was used as the settling tank (1) in FIG. A submersible pump (2) having a discharge rate of 4 m ² / hour was disposed substantially at the bottom of the settling pond. The conduit (3) from the submersible pump was led directly above, bent partway in the middle and connected to the branching device (4). Unlike the case of FIG. 1, the return circuit (10) connected to the upward circuit (5) of the branching device leads from the corner of the settling pond to the bottom, and further connects the discharge port (11) to the center of one side of the square. To discharge the suspension in a direction of about 45 °. When the submersible pump is driven, the discharge port (1
From 1), the suspension refluxed into the tank and a swirling flow occurred.
This swirling flow did not reach the liquid level, so that the suspended matter settled by gravity without any trouble, and the suspension separated into fresh water and concentrated suspension. Since the bottom of the settling basin is constantly swirling, suspended solids (particles) do not accumulate and harden.

From the downward circuit (6), a concentrated suspension could be collected at any time via the flow control valve (8). When a new suspension was introduced from the liquid discharge port (23), fresh water could be continuously collected from the overflow weir (24). The flow control valves (7) and (8) were adjusted to control the overflow, to prevent turbidity from overflowing, and to operate so that particles did not accumulate at the bottom of the settling basin. When introducing a new suspension, a chemical solution was injected through a valve (21). In the case of an acidic clay mineral, an acid such as hydrochloric acid, sulfuric acid, phosphoric acid, or hypochlorous acid or an acidic aqueous solution is used as a chemical liquid so that the suspended solids settle.

Example 3 Rinsing of Suspended Water An example of Example 2 in which the concentrated suspension collected from the downward circuit (6) was washed. There is a method using a thickener concentrator to settle and concentrate a dilute suspension diluted with a washing solution for washing with water. However, since this apparatus is expensive, it is inexpensive and efficient. Is desired.

A tank having a diameter of 3 m and a depth of 6 m was used as a settling tank (1) in FIG. A baffle plate (2) is provided at the cone-shaped outlet at the bottom of the tank to prevent direct suction from the liquid level.
9) is arranged, and the suspension in the tank is injected into the branching device (4) by using a pump (31) having a discharge rate of 4 m ² / hour,
The circuit is branched into an upward circuit (5) and a downward circuit (6).
The suspension was returned to the tank bottom through the return circuit (10) from the upward circuit, and the suspension was discharged tangentially from the discharge port (11). It is preferable to provide a plurality of discharge ports (11).

Thus, the swirling flow is formed only at the bottom of the settling tank (1). Since the liquid surface hardly flows, sedimentation of suspended particles due to gravity occurs without any trouble, and the suspension is separated into a sedimentation concentrate and fresh water. At the bottom of the tank, the suspension is flowing by the swirling flow, so that the particles do not accumulate and harden.

From the downward circuit (6), the flow control valve (8)
, A concentrated suspension could be collected at any time. The concentrated suspension was concentrated by a filter press and a continuous centrifuge to such an extent that dehydration treatment was possible, and a large amount could be collected by continuous operation.

When a new suspension was injected from the liquid supply outlet (23), fresh water could be continuously collected from the overflow weir (24). The flow control valves (7) and (8) were adjusted to control the overflow, to prevent turbidity from overflowing, and to operate so that particles did not accumulate at the bottom of the tank.
When a new suspension is injected, the turbid water does not leak from the overflow weir even if the washing liquid is injected and diluted via the valve (21). Injection of deionized water as a washing liquid allows the suspension or suspension to be highly purified.

Example 4 Metal Surface Treatment A phosphate film treatment is performed as a pre-coating treatment for automobiles and electric appliances. The metal surface is etched with phosphoric acid to deposit phosphate crystals on the metal surface. At this time, various sludges are generated, and the processing liquid is suspended, thereby impairing the performance of the coating film. Therefore, this sludge must be removed.

In order to remove the sludge, a settling apparatus shown in FIG. 2 was used. The suspension treatment liquid (12) containing sludge is passed through a filtration device (13) to a branching device (1).
Lead to 4). The liquid in the branched downward circuit (15) is returned to the original processing tank. The liquid of the branched upward circuit (19) passes through the flow control valve (18) and is discharged from the discharge port (23) through the floor area 2
It is led to a settling tank (1) of m ² and used as a driving force for the swirling flow.
The value of the quotient of the flow rate and the floor area of the settling tank is set to the settling speed of the sludge to be removed, for example, 0.5 m / hour.
This value is determined by the size of the sludge and the particle size to be separated. That is, the flow rate is 1 m ³ / hour. Baffle board (29)
The suspension is collected from around the bottom of the sedimentation tank by bypassing, and guided to the branching device (4) by the external pump (31) via the conduit (30). The liquid of the branched upward circuit (5) is discharged from the discharge port (11) in the settling tank through the flow control valve (7), and gives a swirling flow to the bottom part of the settling tank. The suspended particles gathered at the center of the bottom of the settling tank due to centripetal force and gravity, and a swirling flow of the concentrated suspension was formed. When the flow control valve (8) of the branched downward circuit (6) was opened, a thick suspension could be collected. This is a vertical continuous centrifuge (9)
To remove sludge. Sludge with a large specific metal content and large specific gravity can be selectively collected,
The filtrate was returned to the treatment tank. The overflow liquid from the overflow pipe (24) was led to a larger sedimentation separation device, and sludge having a low sedimentation speed was recovered. Sludge with a large content of light metal elements and low specific gravity was selectively collected.

Even if sludge is removed, divalent iron ions generated in the etching treatment of the steel surface dissolve and accumulate in the treatment liquid, and hinder the etching action. Therefore, an oxidizing agent is added to oxidize divalent iron ions to form trivalent iron ion sludge which is not dissolved in water, and removes the sludge.
In this case, if the oxidizing power of the oxidizing agent is too strong, an oxide film is formed on the metal surface to hinder the etching action. Therefore, sodium nitrite is often used as the oxidizing agent. However, sodium nitrite generates and accumulates sodium ions during the oxidation treatment, so that metal surface treatment becomes impossible. Although direct injection of nitrous acid does not produce sodium ions, nitrous acid acts directly on the metal surface to form a mottled oxide film, impairing good phosphate film formation.

In the apparatus of the present invention, when only a required amount of nitrite or oxidizing gas containing no sodium ions is injected from the injection pipe (20) through the flow control valve (21),
The transparent divalent iron ions were oxidized and turned into sludge of water-insoluble trivalent iron ions, which precipitated out in the sedimentation tank, and were quickly separated and removed. As a result, a clean processing liquid could be maintained in the processing tank, and a good phosphate film could be continuously formed. The sludge was washed using the deionized water that replenishes the evaporating water from the treatment tank, and the sludge was washed in the closed system by returning the washing liquid to the treatment layer. The sludge thus washed and purified can be separately recycled as a resource.

When the coating is applied on a phosphate film in which sodium ions remain, if the coating film is damaged, the undercoat film becomes alkaline and the coating film is easily peeled off. Conventionally, it was necessary to wash with a large amount of deionized water in order to prevent sodium ions from remaining. However, since an enormous amount of water was required, it was not always possible to thoroughly wash. For example, a joint portion of a steel plate of an automobile body is likely to be insufficiently cleaned, and rust is likely to occur even after painting. Particularly when performing high-performance cationic electrodeposition coating, ugly scab rust is generated due to sodium ions remaining at the seam and concentrated by electrolysis. Even after painting, a rustproof seal was required.

In the phosphate coating treatment using the apparatus of the present invention, no sodium ions are contained in the phosphate coating because no sodium ions are mixed in the treatment solution. A sealing treatment may be employed in which the substrate is washed with deionized water and the washing solution is returned to the treatment solution. As a result, sodium ions are not brought into the coating step, particularly the cationic electrodeposition coating bath, and the rust prevention performance of the cationic electrodeposition film can be improved.

Example 5 Electrodeposition Coating with Good Finish Electrodeposition coating with excellent throwing power is an ideal coating method capable of uniformly coating every corner of an object to be coated. However, since it is difficult to control the electrodeposition coating solution as a composite suspension, it is used only for large-scale applications. The first cause of impairing the finish of coating is agglomeration of paint, especially coarse particles such as sludge and dust of lead-based pigments, and the second is the accumulation of monovalent ions that cause abnormal electrolysis reactions. Advanced processes such as ion exchange and ultrafiltration are employed for controlling and managing the ion concentration in the electrodeposition coating. Various types of grit shorten the life of these devices and increase running costs. A separation treatment for efficiently removing coarse particles in an electrodeposition coating solution is desired.

A sedimentation / separation apparatus shown in FIG. 2 suitable for separating and removing coarse particles was employed for this separation treatment. Electrodeposition coating liquid (1
2) from the filtration device (13) to the branching device (14).
The branched downward circuit (15) liquid is returned to the original electrodeposition coating tank. The dust-free electrodeposition coating liquid is supplied from the upper circuit (19)
After passing through the flow control valve (18), the discharge port (23) guides the sedimentation tank (1) to give a swirling flow. The liquid drawn from the external pump (31) bypassing the baffle plate (29) is guided from the branching device (4) to the upward circuit (5), and the flow control valve (7)
Through the outlet (11) into the settling tank (1),
A swirling flow is applied to the bottom of the settling tank.

The agglomerated particles generated in the electrodeposition coating process gathered at the center of the bottom of the sedimentation tank by centripetal force and gravity to form a swirling flow of the concentrated suspension. When the flow control valve (8) of the branched downward circuit (6) was opened, a suspension containing a large amount of aggregated particles could be collected. When this was treated with the horizontal continuous centrifugal separator (9), the aggregates generated in the coating liquid could be concentrated and removed. The electrodeposition coating solution was diluted and could not be directly centrifuged, but according to the apparatus of the present invention, it could be carried out effectively on a small model.

The filtrate and the overflow from the overflow pipe (24)
It was returned to the electrodeposition coating tank, and the electrodeposition coating solution was constantly purified, and the finish of the electrodeposition coating film was well maintained. The overflow liquid in the overflow pipe (24) is free of agglomerated particles, and can be easily treated by ultrafiltration, ion exchange resin or the like. Specifically, the life of the filtration cartridge and the life of the ion exchange resin are improved. As a result, the rust prevention is improved with the finish of the coated product. In particular, the ion exchange treatment, which was difficult to directly process the suspension, has become possible by employing the separation apparatus of the present invention.

According to the apparatus of the present invention, aggregates can be effectively removed. In electrodeposition coating using mica-like particles having excellent design properties, it is necessary to strictly control the coating film abnormality caused by agglomeration of the coating particles because it is particularly conspicuous. Electrodeposition coating with various design properties, such as texture, pearl luster, matte, etc., has become possible.

[0063] By classifying purified suspension of Example 6 organic polymer particles, ion exchange resins, powder coatings, adhesives,
Various organic polymer particles used for fillers and the like have been produced.
It is desired to remove and purify unreacted monomers and the like efficiently. A purification step for removing water-soluble components from a synthetic solution of polymer particles used for paints and adhesives will be exemplified. The sedimentation separation device shown in FIG. 2 was employed as the separation device.

The sample suspension (12) is led to the branching device (14) via the sieving device (13). The branched downward circuit (15) liquid is returned and circulated through the sieving device (13).
The liquid in the upward circuit (19) is guided through the flow control valve (18) from the discharge port (23) so as to form a swirling flow in the settling tank (1). The suspension in the sedimentation tank is pumped by an external pump (31) bypassing the baffle plate (29), guided to the upward circuit (5) from the branching device (4), and discharged through the flow control valve (7). It is discharged from the outlet (11) into the settling tank to form a swirling flow. Suspended particles collect and concentrate at the center of the bottom. From the injection pipe (20) through the flow control valve (21),
Pour deionized water into the settling tank (1). Alternatively, deionized water is injected from the chemical inlet (27) through the outlet (28). The injection flow rate is adjusted so that the washing water is discharged from the overflow pipe (24) at a flow rate determined by the product of the floor area of the sedimentation tank and the sedimentation velocity of the particles to be collected. Is removed. Thus, the washed particles having a predetermined particle diameter or more are concentrated only in the bottom portion of the settling tank (1). Since the concentrated suspension had a swirling flow that did not accumulate, the concentrated suspension could be collected by opening the valve (8) of the branch downward circuit. This was treated with a filtration-type dewatering device (9) to recover desired purified particles. In the case of direct filtration without using the apparatus of the present invention, the life of the filtration membrane is short because the fine particles block the filtration membrane. When the piping of the branching device is turned upside down, sedimentation occurs in the settling tank in a long-term operation. When a large number of separation tanks are combined in series or in parallel, particles having various particle sizes can be classified and collected. Chemical inlet (2
When the density of the medium is reduced by injecting alcohol from 7), sedimentation is promoted and the separation effect is enhanced.

According to the method and the apparatus of the present invention, a cleaning treatment can be performed without the accumulation of particles, the ionic components contained in the powder coating particles can be removed and purified, and the electrostatic coating with high insulation resistance and high coating efficiency can be achieved. For paint. In addition, unreacted monomers that impair the water resistance of the adhesive can be removed. further,
Useful refined fine particles and fine particles usable as a filler can be classified and collected from various mixed powders including the treatment of these used particles and dust particles.

[0066]

According to the present invention, the circuit for refluxing the suspension for driving the swirling flow and the circuit for collecting the concentrated suspension are appropriately arranged by the branching device, so that the bottom of the sedimentation tank is provided. Provided is a sedimentation separation apparatus and a sedimentation separation method for separating and classifying a suspension into a dilute suspension and a concentrated suspension without depositing a concentrated suspension on a portion. The device of the present invention operates stably for a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating one embodiment of the method and apparatus of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating one embodiment of the method and apparatus of the present invention.

FIG. 3 is a schematic cross-sectional view showing one specific example in which the devices of the present invention are connected in series to collect a medium liquid and fresh water.

FIG. 4 is a schematic cross-sectional view showing one specific example of collecting suspended solids from a suspension using the apparatus of the present invention, for example, collecting resources from seawater.

FIG. 5 is a schematic cross-sectional view showing one specific example in the case of classifying suspended particles using the apparatus of the present invention.

[Explanation of symbols]

 1: Sedimentation tank 2: Submersible pump 3: Conduit 4: Branch device 5: Upward circuit 6: Downward circuit 7, 8: Flow control valve 9: Post-processing device 10: Return circuit 11: Discharge port 12: Suspension to be processed Suspended liquid 13: Pretreatment device 14: Branching device 15: Downward circuit 16: Flow control valve 17: Posttreatment device 18: Flow control valve 19: Upward circuit 20: Chemical solution injection pipe 21: Flow control valve 22: Conduit 23 : Discharge port 24: overflow pipe 25: conduit 26: post-processing device 27: chemical liquid inlet 28: discharge port 29: baffle plate 30: conduit 31: external pump 32: conduit 301-304: sedimentation tank 311-314: branch Device 320: Suspension to be treated 330: Chemical solution inlet 340: Baffle plate 341: Conduit to external pump 342: Upper circuit 343: Lower circuit 344: Discharge port 345-346: Overflow means 401- 02: sedimentation tank 410-412: branching device 420: post-processing device 421: discharge port 430: inlet for suspension to be treated 440: chemical liquid inlet 450: discharge port 450: conduit to external pump 451: upward circuit 452 : Downward circuit 453: Discharge port 454: Overflow means 456: Discharge port 457: Baffle plate 460: Overflow pipe 501-503: Sedimentation tank 511-513: Branching device 521-523: Post-processing device 531-533: Suspension Suspended particle collection port 540: dissolution tank 541: powder raw material 550: relay tank 560: overflow means (collection of fresh water) 561: cleaning tank 562: object to be cleaned 563: cleaning object 570: submersible pump 571: conduit 572: top Direction circuit 573: Downward circuit 574: Overflow means

Claims (2)

(57) [Claims] 1. A suspension collected by a pump means from a central part of a bottom of a settling tank for a suspension is branched into an upper circuit and a lower circuit, and the suspension branched into an upper circuit is collected at the bottom of the settling tank. To generate and maintain a swirling flow that does not cause a short-circuit flow from the liquid surface to the bottom of the suspension in the tank, and collect heavy liquid with high suspended solid concentration from the downward circuit. Method of sedimentation of suspension to be performed. 2. A sedimentation tank for introducing a suspension and separating the suspension into a heavy liquid having a high concentration of suspended matter and a light liquid having a low concentration of suspended matter,
(A) pump means for collecting the suspension from the center of the bottom of the settling tank, (b) a conduit for guiding the suspension collected by the pump means to a branching device, and (c) inflow from the conduit. A branching device for branching the suspension into an upward circuit and a downward circuit, (d) a return circuit for returning the suspension branched to the upward circuit to the settling tank, and (e) a bottom of the settling tank A return circuit discharge port is provided in the peripheral part, and the swirling flow that does not cause a short-circuit flow from the liquid level of the suspension in the tank to the bottom is used as the driving force with the flow of the suspension discharged from the return circuit discharge port. A suspension sedimentation / separation apparatus characterized in that the suspension is generated and maintained, and heavy liquid is collected from a downward circuit.