JP2014128777A - Apparatus and method for flocculating, separating and recovering particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for flocculating, separating and recovering particles where impurity solid particles contained in the slurry of a drainage, polluted water and the like are flocculated without applying a direct-current electric field and the floc of the impurity solid particles is continuously recovered from the slurry by performing solid-liquid separation without using a flocculant and a complex device.SOLUTION: An apparatus for flocculating, separating and recovering particles is equipped with a separation vessel and a pair of electrodes applying an electric field to at least a part of the inside of the separation vessel. The separation vessel has a slurry inflow port, a sediment outflow port to flow out the sediment of flocculated particles where the particles are flocculated by applying the electric field, and a supernatant outflow port to flow out separated supernatant. The sediment outflow port is arranged at a lower part of the separation vessel in a vertical direction and the supernatant outflow port is arranged at an upper part of the separation vessel in a vertical direction.

Description

  The present invention relates to a particle aggregation separation and recovery apparatus and a particle aggregation separation and recovery method. In particular, without using a flocculant, impregnated solid particles contained in a slurry such as drainage and sewage are agglomerated by applying a direct current electric field, and the solid agglomerates of the impure solid particles are solid-liquid separated from the slurry. The present invention relates to a particle aggregating and collecting apparatus and a particle aggregating and recovering method.

  In wastewater and sewage treatment, removal of impurity solid particles from wastewater and sewage is carried out by sedimentation, filtration, and the like. Further, in order to facilitate the removal of the impurity solid particles, a flocculant is introduced into the waste water and sewage, and the impurity solid particles are separated and recovered as a high concentration concentrate.

  Examples of such flocculants include inorganic flocculants such as sulfate band (aluminum sulfate), PAC (polyaluminum chloride), polyiron (polyferric sulfate), aluminum chloride, ferric chloride, polyacrylamide, Organic flocculants such as polyamines, DADMAC (diallyldimethylammonium chloride), PDADMAC (polydiallyldimethylammonium chloride) are used.

  However, when such an aggregating agent is used, the aggregate of the impurity solid particles is contaminated by the aggregating agent, and the properties such as pH of the aggregate may deviate from a predetermined value. Moreover, when the flocculant itself is a harmful substance, the aggregate is also harmful. Therefore, when reusing and recycling the impurity solid particles, it is necessary to remove the flocculant, which requires further processing work and cost.

  As a separation method that does not use a flocculant, for example, a technique relating to a two-component separation method and an apparatus therefor has been reported (see Patent Document 1). In this technique, first, an electric field having a magnitude that neutralizes the zeta potential of the impurity liquid particles in the two-component liquid mixture to be treated is applied, and the impurity liquid particles are aggregated and coarsened by intermolecular attractive force. Then, the separated liquid that floats or settles due to the coarsened specific gravity difference is collected and discharged. Thus, it is reported that the above technique efficiently separates two liquids having different specific gravity in a mixed state, such as oil and water, Freon and water, and Freon and oil.

  In addition, research on the promotion of aggregation of particles in oil using an alternating electric field has been reported (see Non-Patent Document 1). In this research, for the purpose of demonstrating the effectiveness of a method for improving the performance of an electrostatic filter, a technique for promoting aggregation by applying an alternating high electric field is described. Furthermore, an experimental result using oil that is an insulating liquid has been reported by an electrostatic filter that captures the aggregated particles.

JP-A-3-77603

Hideki Yanagida, “Study on Aggregation Promotion of Particles in Oil Using AC Electrolysis”, Shinto Technical Report, 21st, November 2003, pp. 70-74

  However, the techniques of Patent Document 1 and Non-Patent Document 1 are specialized for two-liquid separation, and cannot be simply applied to solid-liquid separation of solid particles in a slurry. Moreover, although the technique of patent document 1 and nonpatent literature 1 uses an alternating voltage, when making an impurity solid particle aggregate, it turns out that an impurity solid particle cannot fully aggregate with an alternating voltage. .

  Further, Patent Document 1 and Non-Patent Document 1 do not disclose a technique for continuously agglomerating, separating, and collecting impurity solid particles from a slurry without using a complicated apparatus.

  This invention is made | formed in view of the problem which such a prior art has, and the place made into the subject is contained in slurries, such as drainage and sewage, without using a flocculant and a complicated apparatus. Provided are a particle agglomeration separation and recovery device and a particle agglomeration separation and recovery method for agglomerating impurity solid particles by applying a direct current electric field, solid-liquid separation of the agglomerates of impurity solid particles from a slurry, and continuously recovering There is.

  According to the present invention, the following particle aggregating and collecting apparatus and particle aggregating and recovering method are provided.

[1] A slurry inlet for continuously flowing a slurry containing particles and a dispersion medium, and by applying an electric field to the slurry, a sediment formed by sedimentation of agglomerated particles in which a plurality of the particles are aggregated flows out. And a supernatant outlet for continuously flowing out the dispersion medium separated as a result of aggregation of the particles from the slurry and settling, and the slurry and the dispersion medium. And a pair of electrodes for applying an electric field to at least a part of the inside of the separation container, and the sedimentation outlet is disposed at a lower part in the vertical direction of the separation container. A particle agglomeration separation / recovery device, wherein the supernatant outlet is disposed at an upper part in the vertical direction of the separation container.

[2] The separation container has an elongated shape extending from one end portion to the other end portion, and the pair of electrodes is formed on at least a part of a side surface connecting the one end portion and the other end portion. The particle agglomeration separation and recovery apparatus according to [1], which is provided.

[3] The elongated shape is a rectangular parallelepiped shape having one end surface and the other end surface facing each other at the one end portion and the other end portion, and connects the one end surface and the other end surface. The particle agglomeration separation / recovery device according to [2], wherein the pair of electrodes are disposed on two opposing side surfaces.

[4] The separation container has the elongated shape having a longitudinal direction parallel to a horizontal direction, the slurry inlet on the one end side, and the settling on a lower portion in the vertical direction on the other end side. The particle agglomeration separation / recovery device according to [2] or [3], which has a distribution outlet and has the supernatant outlet at the upper part in the vertical direction on the other end side.

[5] The separation container is inclined so that the one end is higher than the other end, and has the slurry inlet on the one end, and the other end The particle agglomeration separation / recovery device according to [2] or [3], wherein the sedimentation flow outlet is provided at a lower portion in the vertical direction on the side, and the supernatant outlet is provided at an upper portion in the vertical direction on the other end side. .

[6] The particle agglomeration separation and recovery device according to any one of [2] to [5], wherein the sedimentation flow outlet is disposed on the bottom surface on the other end side.

[7] The particle agglomeration separation / recovery device according to any one of [2] to [6], wherein the slurry inlet is disposed at an upper part in the vertical direction of the one end.

[8] The separation container has an outer cylinder in which a central axis parallel to a direction in which the cylinder extends is arranged in parallel with a vertical direction, and the central axis and the central axis of the outer cylinder are common, and at least a lower end portion is the outer cylinder. The particle agglomeration separation and recovery device according to [1], further including an inner cylinder inserted into the cylinder.

[9] At least a part of the peripheral surface of the inner cylinder is provided with one of the pair of electrodes, and is a peripheral surface of the outer cylinder, and the inner cylinder is at least opposite to a portion including the one of the pair of electrodes. The particle agglomeration separation and recovery device according to [8], wherein the part to be provided is provided with the other of the pair of electrodes.

[10] The slurry containing particles and a dispersion medium is continuously allowed to flow into the separation container filled with the dispersion medium, and an electric field is applied to the slurry that has flowed into the separation container. Aggregated particles in which a plurality of the particles in the slurry are aggregated are settled at the bottom of the separation container, and the dispersion medium is continuously discharged as a supernatant, and the aggregated particles are used as a sediment in a separate path from the supernatant. A particle agglomeration separation and recovery method comprising continuously flowing out and solid-liquid separation.

[11] The electric field is applied by applying a voltage to a pair of electrodes that are disposed in at least a part of the separation container and sandwich the slurry flowing into the separation container. The particle agglomeration separation and recovery method according to [10] above.

[12] The particle aggregation separation and recovery method according to [10] or [11], wherein the electric field is applied by a direct current voltage with an electric field strength of 0.25 to 5 V / cm.

[13] The particle agglomeration separation and recovery method according to any one of [10] to [12], wherein an inflow rate of the slurry is larger than an outflow rate of the sediment.

  The particle aggregation separation and recovery apparatus of the present invention and the particle aggregation separation and recovery method of the present invention apply a DC electric field to impurity solid particles contained in a slurry such as drainage and sewage without using a flocculant or a complicated apparatus. Thus, it is possible to agglomerate, to separate solid-liquid aggregates of impurity solid particles from the slurry, and to continuously collect them.

It is a perspective view showing typically one embodiment of the particle aggregation separation recovery device of the present invention. It is a side view showing typically one embodiment of the particle aggregation separation recovery device of the present invention. It is a perspective view which shows typically other embodiment of the particle aggregation separation collection | recovery apparatus of this invention. 4 is a graph showing measurement results of solid particle concentration in Example 1. 4 is a graph showing the measurement results of particle diameter in Example 1. 6 is a graph showing measurement results of solid particle concentration in Example 2.

  Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that modifications, improvements, and the like appropriately added to the embodiments described above fall within the scope of the present invention.

  For convenience of explanation, first, an embodiment of the particle agglomeration separation and recovery method of the present invention will be described, and then an embodiment of the particle agglomeration separation and recovery apparatus of the present invention will be described.

1. Particle aggregation separation and recovery method (first embodiment)
In the particle agglomeration separation and recovery method of the present invention, a slurry containing particles and a dispersion medium is continuously allowed to flow into a separation container filled with the dispersion medium, and an electric field is applied to the slurry that has flowed into the separation container. Is applied to the bottom of the separation vessel, the dispersion medium is continuously discharged as a supernatant, and the aggregated particles are used as a sediment. It is a method including continuously flowing out by a separate path from the supernatant and performing solid-liquid separation.

  By such a particle agglomeration separation and recovery method, impurity solid particles contained in a slurry such as drainage and sewage can be aggregated by applying a direct current electric field without using a flocculant or a complicated device, and the impurity solids from the slurry Particle aggregates can be continuously collected by solid-liquid separation. Hereinafter, an embodiment (first embodiment) of the particle aggregation separation and recovery method of the present invention will be described.

  In this embodiment, by applying an electric field to the solid particles in the slurry, the aggregated particles generated by dielectric polarization of the solid particles are settled and separated. That is, each solid particle to which an electric field is applied has a portion having a positive charge and a portion having a negative charge. A portion having a positive charge of one solid particle and a portion having a negative charge of another solid particle Will be attracted by Coulomb force. By this action, the dielectrically polarized solid particles attract each other and aggregate to form aggregated particles. The aggregated particles settle in the slurry and accumulate at the bottom of the separation container. Then, the agglomerated particles (sediment) that have settled at the bottom of the separation container and the dispersion medium (supernatant) are caused to flow out in separate paths, so that the sediment and the supernatant are separated into solid and liquid and recovered separately. .

  In this embodiment, in addition to the application of the electric field described above, the inside of the separation container is filled with a dispersion medium, and the slurry is allowed to flow into the separation container filled with the dispersion medium. Thus, by filling the separation container with the dispersion medium in advance, the dispersion medium and the aggregated particles can be effectively separated even immediately after the start of the inflow of the slurry. That is, since the inside of the separation container is filled with the dispersion medium, a distance between the upper surface of the dispersion medium and the lower surface of the dispersion medium is secured even immediately after the start of the inflow of the slurry, and settles near the lower surface of the dispersion medium. It is difficult for the agglomerated particles and the dispersion medium in the vicinity of the upper surface to coexist, and it is possible to effectively separate the supernatant and the sediment.

  In this embodiment, since the inflow of the slurry into the separation container, the outflow of the supernatant of the dispersion medium (also referred to as “overflow”), and the outflow of the sediment of the aggregated particles are performed simultaneously, the solid particles are aggregated and separated. The recovery can be performed continuously for a long time. Furthermore, in this embodiment, since a filter or the like is not used for separating the solid particles and the dispersion medium, there is no problem of clogging or deterioration of the filter, and there is no need for replacement or regeneration. In addition, since no filter or the like is used, the configuration of the apparatus can be simplified.

1-1. Slurry In the particle aggregation separation and recovery method of the present invention, the slurry to be treated is not particularly limited as long as it contains particles and a dispersion medium. For example, wastewater or sewage can be treated. Examples of drainage and sewage include drainage discharged from water and sewage systems, sewage, manure discharged from livestock industry, construction sludge, and the like.

In the present embodiment, the solid particles contained in the slurry are not particularly limited as long as they are dielectrically polarized by application of an electric field, and a plurality of solid particles can aggregate to form an aggregate. For example, solid particles such as clay, organic matter, etc. contained in drainage and sewage, alumina, bentonite, barium titanate (BaTiO ₃ ), and the like can be given.

  In this embodiment, for example, solid particles of about 0.01 to 1 μm can be efficiently separated from the slurry. Moreover, as a density | concentration of the solid particle in a slurry, the slurry of about 100 ppm-1 vol% can be processed efficiently, for example.

  In the present embodiment, the dispersion medium contained in the slurry is not particularly limited as long as it can disperse the solid particles and does not inhibit the above-described dielectric polarization. For example, in the case of drainage or sewage, the dispersion medium can be water, and the separation container may be filled with distilled water or the like.

1-2. Separation container The shape of the separation container used in the present embodiment has a slurry inflow port through which slurry flows in, a sediment flow outlet through which sediment of aggregated particles flows out, and a supernatant outflow port through which the supernatant of the dispersion medium flows out. There is no particular limitation as long as the dispersion medium can be filled.

  The material of the separation container is preferably a material that does not easily affect the electric field applied to the slurry inside the separation container. For example, resins such as acrylic and polypropylene, glass, stainless steel treated with an insulating film, and the like can be used.

1-3. Application of electric field In this embodiment, an electric field is applied to the slurry to agglomerate solid particles in the slurry and settle as aggregated particles at the bottom of the separation vessel.

  In order to apply an electric field to the slurry, for example, a pair of electrodes is disposed on at least a part of the separation container, and the slurry in the separation container is sandwiched, and a voltage is applied to the pair of electrodes. Just do it. For example, in the case of a rectangular parallelepiped-shaped separation container, an anode may be disposed on one of two opposing side surfaces, and a cathode may be disposed on the other side. In order to further promote the aggregation of solid particles, It is preferable to be disposed on the entire surface.

  The electrode is not particularly limited. For example, a plate-like or wire mesh-like electrode can be used. The material of the electrode may also be a commonly used material such as stainless steel or carbon.

  The electric field applied to the slurry preferably has an electric field strength of 0.25 to 5 V / cm, more preferably 2.5 to 5 V / cm, and particularly preferably 3.75 to 4 V / cm. . Moreover, it is preferable that the electric field applied to the slurry is a direct current voltage. When the electric field strength of the electric field applied to the slurry is less than 0.25 V / cm, the solid particles in the slurry may not be sufficiently dielectrically polarized and aggregated. On the other hand, if the electric field strength of the electric field applied to the slurry is more than 5 V / cm, not only the energy more than necessary is input, but also the slurry is heated and the dispersion medium evaporates. May occur. In addition, when the electric field applied to the slurry is based on an alternating voltage, it is difficult to obtain the effect of aggregation of solid particles due to dielectric polarization, and the aggregated particles cannot be effectively settled. May be insufficiently separated.

1-4. Inflow of slurry, outflow of sediment and supernatant The means for allowing the slurry to flow into the separation container and outflow of the sediment and supernatant out of the separation container is not particularly limited. For example, it is possible to use a pump that draws up the slurry from a slurry tank that stores the slurry and feeds the slurry from the slurry inlet into the separation container. Further, a stopcock may be provided at the sedimentation outlet, the supernatant outlet, or both to adjust the outflow rate. A small amount of a dispersion medium may be contained in the sediment flowing out from the sediment distribution outlet.

  In this embodiment, by adjusting the inflow speed of the slurry, the outflow speed of the sediment, and the outflow speed of the supernatant into the separation container, the agglomerated particles and the dispersion medium are continuously and continuously from the slurry. And can be separated. Here, the inflow speed of the slurry is equal to the sum of the outflow speed of the sediment in which the aggregated particles settle and concentrate, and the outflow speed of the supernatant. In this embodiment, in order to perform a steady operation (a state in which separation can be continued without changing the interface position between the slurry and the sediment), assuming that no particles are contained in the supernatant, the inflow rate of the slurry and the sedimentation The ratio of the product outflow rate (slurry inflow rate / sediment outflow rate) should be equal to the concentration ratio (sediment concentration / slurry concentration). For example, when separating a sediment containing aggregated particles in which the aggregated particles are concentrated at a concentration of 10 times from the slurry, the inflow rate of the slurry needs to be 10 times the outflow rate of the sediment. If the inflow speed of the slurry is faster than this, the interface between the slurry and the sediment may rise and particles may enter the supernatant. On the other hand, if the inflow rate of the slurry is slower than 10 times the outflow rate of the sediment, the concentration of the sediment may decrease.

2. Particle aggregating and collecting apparatus (second and third embodiments)
The particle aggregation separation and recovery apparatus of the present invention includes a separation container and a pair of electrodes for applying an electric field to at least a part of the inside of the separation container. The separation container is a slurry inflow port through which slurry containing particles and a dispersion medium is continuously flowed in, and an electric field is applied to the slurry to discharge sediment formed by sedimentation of aggregated particles in which a plurality of particles are aggregated. It has a sedimentation outlet and a supernatant outlet through which the dispersion medium separated by aggregation and settling of particles from the slurry is continuously discharged as a supernatant. Furthermore, the sedimentation outlet is disposed in the lower part of the separation container in the vertical direction, and the supernatant outlet is disposed in the upper part of the separation container in the vertical direction. Hereinafter, embodiments (second and third embodiments) of the particle agglomeration separation and recovery apparatus of the present invention for realizing the above-described particle agglomeration separation and recovery method will be described with reference to the drawings.

2-1. Particle aggregating and collecting apparatus (second embodiment)
One embodiment (second embodiment) of the particle agglomeration separation and recovery apparatus of the present invention is an elongated shape in which the separation container extends from one end to the other end in the above-described particle aggregation separation and recovery apparatus, A pair of electrodes is provided on at least a part of the side surface connecting the end of the first end and the other end.

  The particle agglomeration separation and recovery apparatus of the present embodiment can be configured as shown in FIGS. 1 and 2, for example. FIG. 1 is a perspective view schematically showing an embodiment of the particle agglomeration separation and recovery apparatus of the present invention, and FIG. 2 is a side view schematically showing an embodiment of the particle agglomeration separation and recovery apparatus of the present invention. is there.

  1 and 2, the elongated shape is a rectangular parallelepiped shape having one end surface 13 and the other end surface 14 facing each other at one end and the other end, respectively, and one end surface 13 and the other end surface 14. A configuration is shown in which a pair of electrodes 51a and 51b are arranged on two opposing side surfaces 12a and 12b that connect the two. Further, the separation container 10 has an elongated shape whose longitudinal direction is parallel to the horizontal direction, has a slurry inlet 15 on one end (one end face 13) side, and the other end (the other end face 14). The structure which has the sediment distribution outlet 16 and the supernatant outlet 17 in the side is shown.

  In the particle agglomeration separation and recovery apparatus of the present embodiment, the slurry flows into the separation container 10 from the slurry inlet 15 disposed on one end surface 13. The inflowing slurry reaches a region sandwiched between the electrodes 51a and 51b disposed on the side surfaces 12a and 12b of the separation container 10. In this region, the solid particles in the slurry are dielectrically polarized by the electric field generated by the voltage applied to the electrodes 51a and 51b, and aggregated particles are formed. The agglomerated particles formed here cannot float in the slurry, settle, deposit on the bottom of the separation vessel 10, and flow out of the separation vessel 10 from the sedimentation outlet 16 disposed on the bottom surface. And recovered as sediment. On the other hand, the dispersion medium is pushed out by the slurry that sequentially flows from the slurry inlet 15, and flows out as a supernatant from the supernatant outlet 17 disposed on the other end face 14 and is collected.

  By having such a configuration, the particle agglomeration separation and recovery apparatus of the present embodiment can continuously agglomerate, separate, and recover individual particles from the slurry without using a flocculant or a complicated apparatus. is there.

2-1-1. Separation container In this embodiment, the separation container 10 has a rectangular parallelepiped shape. This rectangular parallelepiped shape has one end face 13 and the other end face 14 that face each other in the horizontal direction or the substantially horizontal direction. Moreover, this rectangular parallelepiped shape has a pair of side surface 12 (side surface 12a and side surface 12b) which opposes a horizontal direction and connects one end surface 13 and the other end surface 14. As shown in FIG.

  In the present embodiment, the rectangular parallelepiped shape is preferably long in the axial direction connecting the one end surface 13 and the other end surface 14. By making the shape long in the axial direction, it is possible to widen the region where aggregated particles in which solid particles are aggregated by application of an electric field can settle, and to make solid-liquid separation of sediment and supernatant more effective. Is possible.

  The separation container 10 has a slurry inlet 15 on one end face 13 side in order to allow the slurry to flow into the separation container 10. The slurry inlet 15 can be connected to a pump 8 that pumps the slurry from the slurry tank 9 storing the slurry and sends the slurry from the slurry inlet 15 into the separation container 10.

  The slurry inflow port 15 is preferably formed at the upper part in the vertical direction of the one end face 13. Since the slurry inlet 15 is formed at the upper portion of the one end face 13, when aggregated particles are deposited on the bottom of the separation container 10, the accumulated aggregated particles are caused by the hydraulic pressure of the slurry flowing from the slurry inlet 15. It is possible to suppress re-diffusion of the aggregated particles.

  Since the separation container 10 applies a voltage to the pair of electrodes 51 and applies an electric field to the slurry in the separation container 10, a plurality of the particles are aggregated to flow out the settled sediment. A sediment distribution outlet 16 is provided at the lower end in the vertical direction on the end face 14 side. A stopcock or the like may be connected to the sedimentation outlet 16 in order to adjust the sediment flow rate. The sediment flowing out from the sediment distribution outlet 16 may contain a small amount of a dispersion medium.

  The sedimentation outlet 16 is preferably disposed on the bottom surface in the vicinity of the other end surface 14 of the separation container 10. By configuring in this way, the sediment of aggregated particles can be sequentially flowed out of the separation vessel 10 from the bottom of the region in the separation vessel 10 where sediment is accumulated most. Liquid separation can be made more effective.

  The separation container 10 has a supernatant outlet 17 in the upper part in the vertical direction on the other end face 14 side in order to flow out the supernatant from which particles have settled and separated from the slurry. A stopcock or the like may be connected to the supernatant outlet 17 in order to adjust the outflow speed of the supernatant.

  It is preferable that the supernatant outlet 17 is disposed at the upper part in the vertical direction of the other end face 17 of the separation container 10. By configuring in this way, the most agglomerated particles settle in the separation container 10 and the sediment is sequentially discharged from the sedimentation flow outlet 16 to efficiently remove the supernatant from the region where the agglomerated particles are most separated and removed. Therefore, it is possible to make the solid-liquid separation of the sediment and the supernatant more effective.

  The material of the separation container is preferably a material that does not easily affect the electric field applied to the slurry inside the separation container. For example, resins such as acrylic and polypropylene, glass, stainless steel treated with an insulating film, and the like can be used.

  The separation container 10 is preferably inclined so that one end surface 13 side is higher than the other end surface 14 side. As an inclination angle, it can be set as about 1-15 degrees, for example. By tilting the separation container 10 in this way, it becomes easy to deposit sediment on the bottom of the other end face 14 side.

2-1-2. Electrodes 51 a and 51 b are disposed on at least a part of both side surfaces 12 a and 12 b of the electrode separation container 10. These electrodes 51a and 51b can be connected to a power source 5, for example, in order to apply a voltage.

  The power source 5 is not particularly limited, but it is preferable that an electric field can be applied between the pair of electrodes 51a and 51b with an electric field strength of 0.25 to 5 V / cm. The electric field strength is more preferably 2.5 to 5 V / cm, and particularly preferably 3.75 to 4 V / cm. The power source 5 is preferably one that can be applied with a DC voltage. When the electric field strength of the electric field applied to the slurry is less than 0.25 V / cm, the solid particles in the slurry may not be sufficiently dielectrically polarized and aggregated. On the other hand, if the electric field strength of the electric field applied to the slurry is more than 5 V / cm, not only the energy more than necessary is input, but also the slurry is heated and the dispersion medium evaporates. May occur. In addition, when the electric field applied to the slurry is based on an alternating voltage, it is difficult to obtain the effect of aggregation of solid particles due to dielectric polarization, and the aggregated particles cannot be effectively settled. May be insufficiently separated.

  The polarity of the electrode is not limited, and the electrode 51a may be a positive electrode, the electrode 51b may be a negative electrode, the electrode 51a may be a negative electrode, and the electrode 51b may be a positive electrode. In order to improve the aggregation effect of the solid particles, these electrodes 51a and 51b are preferably disposed on the entire surfaces of the side surfaces 12a and 12b of the separation container 10. By comprising in this way, an electric field is applied by electrode 51a, 51b over the whole region in the separation container 10, and the production | generation of an aggregated particle can be promoted.

  The electrode is not particularly limited. For example, a plate-like or wire mesh-like electrode can be used. The material of the electrode may also be a commonly used material such as stainless steel or carbon.

2-2. Particle aggregating and collecting apparatus (third embodiment)
Another embodiment (third embodiment) of the particle agglomeration separation and recovery apparatus of the present invention is the above-described particle agglomeration separation and recovery apparatus, in which the separation container has a central axis parallel to the direction in which the cylinder extends, arranged parallel to the vertical direction And an inner cylinder in which the central axis and the central axis of the outer cylinder are common and at least the lower end portion is inserted into the outer cylinder. This separation container has a slurry inlet opening at the bottom of the inner cylinder at the lower end of the inner cylinder, a sediment flow outlet at the bottom of the outer cylinder, and a supernatant outlet at the upper end of the outer cylinder. Have.

  The particle agglomeration separation and recovery apparatus of the present embodiment can be configured as shown in FIG. 3, for example. FIG. 3 is a perspective view schematically showing another embodiment of the particle aggregating and collecting apparatus of the present invention.

  In FIG. 3, at least a part of the peripheral surface of the inner cylinder is provided with one of a pair of electrodes arranged in a ring shape, and the outer cylinder is a peripheral surface, and the inner cylinder includes one of the pair of electrodes. A configuration is shown in which the other of the pair of electrodes arranged in a ring shape is provided at least in the facing portion.

  In the particle agglomeration separation and recovery apparatus of this embodiment, the slurry flows into the separation container 20 from the slurry inlet 25 disposed at the lower end of the inner cylinder 23 and diffuses into the separation container 20. A part of the diffused slurry reaches a region sandwiched between the electrodes 52 a and 52 b disposed in the inner cylinder 23 and the outer cylinder 24. In this region, the solid particles in the slurry are dielectrically polarized by the electric field generated by the voltage applied to the electrode 52, and aggregated particles are formed. The agglomerated particles formed here cannot float in the slurry, settle down, and flow out from the sedimentation outlet 26 disposed at the lower end of the outer cylinder 24 to the outside of the separation container 20, Collected as sediment. On the other hand, the dispersion medium is pushed out by the slurry that sequentially flows from the slurry inlet 25, flows out as a supernatant from the supernatant outlet 27 disposed at the upper end of the outer cylinder 24, and is collected. In the present embodiment, the inside of the separation container 20 means a space defined by the outer peripheral surface and the bottom surface of the inner cylinder 23 and the inner peripheral surface, the upper surface, and the bottom surface of the outer cylinder 24.

  By having such a configuration, the particle agglomeration separation and recovery apparatus of the present embodiment can continuously agglomerate, separate, and recover individual particles from the slurry without using a flocculant or a complicated apparatus. is there.

2-2-1. Separation Container In this embodiment, the separation container 20 includes an outer cylinder 24 and an inner cylinder 23 that are coaxial, that is, have a common central axis, and the central axis is parallel to the vertical direction. At least the lower end portion of the inner cylinder 23 is inserted into the outer cylinder 24. That is, in a region where the inner cylinder 23 is inserted into the outer cylinder 24 and is sandwiched between the inner cylinder 23 and the outer cylinder 24, a voltage is applied to the pair of electrodes 52 disposed on the inner cylinder 23 and the outer cylinder 24. As a result, an electric field is generated, and solid particles in the slurry that have entered the region are dielectrically polarized and agglomerate to become aggregated particles and settle to the bottom of the outer cylinder 24.

  A slurry inlet 25 is disposed at the lower end of the inner cylinder 23 of the separation container 20 in order to allow the slurry to flow into the separation container 20. That is, the slurry passes through the inner cylinder 23 from the upper end of the inner cylinder 23 and flows into the separation container 20 from the slurry inlet 25 at the lower end of the inner cylinder 23. A pump 8 can be connected to the upper end of the inner cylinder 23 to pump up the slurry from the slurry tank 9 storing the slurry and send the slurry from the slurry inlet 25 into the separation container 20.

  At the bottom of the outer cylinder 24, a sedimentation flow outlet 26 is provided to allow the sediment of aggregated particles that have been aggregated and settled by applying an electric field to flow out of the separation container 20. A stopcock or the like may be connected to the sedimentation outlet 26 in order to adjust the sediment flow rate. The sediment flowing out from the sediment distribution outlet 26 may contain a small amount of a dispersion medium.

  A supernatant outlet 27 is disposed at the upper end of the outer cylinder 24 in order to flow out the supernatant from which the solid particles have settled and separated from the slurry. The supernatant outlet 27 may be the upper end surface of the cylindrical portion of the outer cylinder 24 and does not require a special covering member or the like. In other words, the slurry may be configured to be pushed out by the slurry flowing in from the slurry inlet 25 and overflow from the supernatant outlet 27 of the upper end portion of the outer cylinder 24. The supernatant overflowing from the supernatant outlet 27 may be collected by flowing down the outer wall surface of the outer cylinder 24 and separating it so as not to be mixed with the agglomerated particles flowing out from the sedimentation outlet 26.

  The lower portion of the outer cylinder 24 may be tapered. That is, as the outer cylinder 24, a thickener can be used.

2-2-2. One of the pair of electrodes 52 (electrode 52 a) disposed in a ring shape on at least a part of the peripheral surface of the outer cylinder 24 of the electrode separation container 20, and arranged in a ring shape on at least a part of the peripheral surface of the inner cylinder 23. The other of the provided pair of electrodes 52 (electrode 52b) is provided, and the pair of electrodes 52 are disposed to face each other so as to sandwich the slurry. These electrodes 52a and 52b can be connected to a power source 5, for example, in order to apply a voltage.

  The power source 5 is not particularly limited, but it is preferable that an electric field can be applied between the pair of electrodes 52a and 52b with an electric field strength of 0.25 to 5 V / cm. The electric field strength is more preferably 2.5 to 5 V / cm, and particularly preferably 3.75 to 4 V / cm. The power source 5 is preferably one that can be applied with a DC voltage. When the electric field strength of the electric field applied to the slurry is less than 0.25 V / cm, the solid particles in the slurry may not be sufficiently dielectrically polarized and aggregated. On the other hand, if the electric field strength of the electric field applied to the slurry is more than 5 V / cm, not only the energy more than necessary is input, but also the slurry is heated and the dispersion medium evaporates. May occur. In addition, when the electric field applied to the slurry is based on an alternating voltage, it is difficult to obtain the effect of aggregation of solid particles due to dielectric polarization, and the aggregated particles cannot be effectively settled. May be insufficiently separated.

  The polarity of the electrode is not limited, and the electrode 52a may be a positive electrode, the electrode 52b may be a negative electrode, the electrode 52a may be a negative electrode, and the electrode 52b may be a positive electrode. In order to improve the agglomeration effect of the solid particles, these electrodes 52a and 52b are disposed on the entire surface in a region where the peripheral surface of the inner cylinder 23 of the separation container 20 and the peripheral surface of the outer cylinder 24 are opposed to each other. It is preferable. By comprising in this way, an electric field is applied by electrode 52a, 52b over the said whole area | region in the separation container 20, and the production | generation of an aggregated particle can be promoted.

  The electrode is not particularly limited. For example, a cylindrical or wire mesh electrode can be used. As long as the material of the electrode can be disposed on the cylindrical peripheral surfaces of the inner cylinder 23 and the outer cylinder 24 of the separation container 20, stainless steel, carbon, or the like may be generally used.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

Example 1
The performance of the particle agglomeration separation and recovery apparatus of the second embodiment of the present invention was evaluated using the apparatus of FIG.

  As a sample to be separated, a slurry obtained by dispersing easily sintered alumina (trade name “AES-12” manufactured by Sumitomo Chemical Co., Ltd., average particle size 0.5 μm) in distilled water at a volume concentration of 300 ppm was used. The pH of the prepared slurry was 7.5. For the pH measurement, a compact pH meter (model “Twin pH B-212”) manufactured by HORIBA, Ltd. was used. Before starting the experiment, the slurry was ultrasonically stirred.

  As a separation container, a rectangular parallelepiped acrylic separation container having a side length of 100 mm and a length between both end faces of 500 mm was used for both end faces (one end face 13 and the other end face 14 in FIG. 1). On both side surfaces of this separation container, a wire mesh-like stainless steel electrode was disposed on the entire surface of each side so that one side surface was a positive electrode and the other side surface was a negative electrode. The inside of the separation container was filled with distilled water as a dispersion medium.

  Next, the slurry was introduced into the separation container from the slurry inlet using a pump, and a DC voltage of 20 V was applied to the electrodes. The slurry inflow rate was 5.8 ml / min and the sediment outflow rate was 2.0 ml / min.

  The solid particle concentration of each of the aggregated particles collected from the sedimentation flow outlet and the supernatant collected from the supernatant outlet was measured. A turbidity meter (model number TR55) manufactured by KRK was used for turbidity measurement. The results are shown in FIG. In FIG. 4, the horizontal axis represents the elapsed time (minutes) from the start of electric field application, and the vertical axis represents the volume concentration (ppm) of the solid particles.

  Moreover, the transition of the particle diameter with respect to time was evaluated about the sediment of the aggregated particle. The results are shown in FIG. In FIG. 5, the horizontal axis represents the elapsed time (minutes) from the start of electric field application, and the vertical axis represents the median diameter (μm) of the individual particles. For measuring the median diameter, a dynamic light scattering particle diameter measuring device (model number LB550NT) manufactured by HORIBA, Ltd. was used.

(Comparative Example 1)
Evaluation was performed in the same manner as in Example 1 except that no voltage was applied to the electrode (the voltage was set to 0 V). The results are shown in FIGS.

  From comparison between Example 1 and Comparative Example 1 shown in FIG. 4 and FIG. 5, by applying an electric field, the solid particle concentration in the supernatant was kept low at 10 ppm or less even after a long period of time. It was shown that the solid particles can be continuously aggregated, separated and recovered from the slurry by the apparatus of the present invention.

(Example 2)
The performance of the particle agglomeration separation and recovery apparatus of the third embodiment of the present invention was evaluated using the apparatus of FIG.

  As a sample to be separated, a slurry prepared by dispersing easily sintered alumina (trade name “AES-12” manufactured by Sumitomo Chemical Co., Ltd., average particle size of 0.5 μm) in distilled water at a volume concentration of 1000 ppm was used. The pH of the prepared slurry was 7.5. For the pH measurement, a compact pH meter (model “Twin pH B-212”) manufactured by HORIBA, Ltd. was used. Before starting the experiment, the slurry was ultrasonically stirred.

  The separation container includes an outer cylinder having an inner diameter of 80 mm at the upper end and a height of 120 mm, and an inner cylinder having a diameter of 40 mm and a height of 150 mm, and is 100 mm from the lower end of the inner cylinder. A separation container having a portion inserted into the outer cylinder was used. The separation container was provided with a metal mesh-like stainless steel electrode so that the outer peripheral surface of the inner cylinder was an anode and the inner peripheral surface of the outer cylinder was a negative electrode. The outer cylinder was filled with distilled water as a dispersion medium.

  Next, the slurry was introduced into the separation container from the slurry inlet using a pump, and a DC voltage of 20 V was applied to the electrodes. The slurry inflow rate was 7.0 ml / min and the sediment outflow rate was 1.5 ml / min.

  The solid particle concentration of each of the aggregated particles collected from the sedimentation flow outlet and the supernatant collected from the supernatant outlet was measured. A turbidity meter (model number TR55) manufactured by KRK was used for turbidity measurement. The results are shown in FIG. In FIG. 6, the horizontal axis represents the elapsed time (minutes) from the start of the electric field, and the vertical axis represents the volume concentration (ppm) of the solid particles.

(Comparative Example 2)
Evaluation was performed in the same manner as in Example 2 except that no voltage was applied to the electrode (the voltage was set to 0 V). The results are shown in FIG.

  From the comparison between Example 2 and Comparative Example 2 shown in FIG. 6, by applying an electric field, the solid particle concentration in the supernatant was kept low at 10 ppm or less even after a long period of time. It was shown that solid particles can be continuously aggregated, separated and recovered from the slurry by the apparatus.

  The particle agglomeration separation and recovery apparatus of the present invention can efficiently concentrate and separate impurity solid particles from waste water, sewage, etc. without using a flocculant, so that the concentrate, supernatant liquid, or both can be reused and recycled. Is possible. Furthermore, since a filter and a complicated apparatus are not required, the operation can be simplified or the efficiency can be improved.

1, 2: Particle aggregation separation and recovery device, 5: Power source, 8: Pump, 9: Slurry tank, 10, 20: Separation container, 12, 12a, 12b: Side surface, 13: One end surface, 14: The other end surface, 15, 25: Slurry inlet, 16, 26: Sediment flow outlet, 17, 27: Supernatant outlet, 23: Inner cylinder, 24: Outer cylinder, 51, 51a, 51b, 52, 52a, 52b: Electrode.

Claims (13)

A slurry inlet for continuously flowing a slurry containing particles and a dispersion medium,
By applying an electric field to the slurry, a sediment flow outlet for discharging sediment formed by sedimentation of aggregated particles in which a plurality of the particles are aggregated, and
A supernatant outlet for continuously flowing out the dispersion medium separated as a result of agglomeration and sedimentation of the particles from the slurry;
A separation container for continuously solid-liquid separating the slurry into the particles and the dispersion medium;
A pair of electrodes for applying an electric field to at least a portion of the interior of the separation vessel;
With
The particle agglomeration separation and recovery device, wherein the sedimentation outlet is disposed at a lower part in the vertical direction of the separation container, and the supernatant outlet is disposed at an upper part in the vertical direction of the separation container. The separation container is
It is an elongated shape that extends from one end to the other end,
The particle agglomeration separation and recovery apparatus according to claim 1, wherein the pair of electrodes are provided on at least a part of a side surface connecting the one end and the other end. The elongated shape is
The one end portion and the other end portion have a rectangular parallelepiped shape each having one end surface and the other end surface facing each other,
The particle agglomeration separation and recovery device according to claim 2, wherein the pair of electrodes are disposed on two opposing side surfaces connecting the one end surface and the other end surface. The separation container is
The longitudinal direction of the elongated shape is parallel to the horizontal direction;
The slurry inlet is provided on the one end side,
The sediment distribution outlet is provided in the lower vertical direction on the other end side,
The particle agglomeration separation and recovery device according to claim 2 or 3, wherein the supernatant outlet is provided in the upper part of the other end side in the vertical direction. The separation container is inclined such that the one end is higher than the other end;
The slurry inlet is provided on the one end side,
The sediment distribution outlet is provided in the lower vertical direction on the other end side,
The particle agglomeration separation and recovery device according to claim 2 or 3, wherein the supernatant outlet is provided in the upper part of the other end side in the vertical direction.   The particle agglomeration separation and recovery device according to any one of claims 2 to 5, wherein the sedimentation outlet is disposed on a bottom surface on the other end side.   The particle agglomeration separation and recovery apparatus according to any one of claims 2 to 6, wherein the slurry inflow port is disposed at an upper part in the vertical direction of the one end portion. The separation container is
An outer cylinder in which a central axis parallel to the direction in which the cylinder extends is arranged parallel to the vertical direction;
An inner cylinder in which the central axis and the central axis of the outer cylinder are common and at least a lower end portion is inserted into the outer cylinder;
The apparatus for aggregating and collecting particles according to claim 1. The separation container is
One of the pair of electrodes is provided on at least a part of the peripheral surface of the inner cylinder,
The particle aggregation according to claim 8, wherein the outer cylinder is provided with the other of the pair of electrodes at a portion at least facing the portion of the outer cylinder that includes the one of the pair of electrodes. Separation and recovery device. A slurry containing particles and a dispersion medium is allowed to flow into a separation container filled with the dispersion medium,
By applying an electric field to the slurry that has flowed into the separation container, the aggregated particles in which the particles in the slurry are aggregated are allowed to settle at the bottom of the separation container, and the dispersion medium and the aggregated particles are , A particle agglomeration separation and recovery method including solid-liquid separation as supernatant and sediment, respectively.   The electric field is applied by applying a voltage to a pair of electrodes disposed in at least a part of the separation container and sandwiching the slurry flowing into the separation container. 10. The particle aggregating and collecting method according to 10.   The particle aggregation separation and recovery method according to claim 10 or 11, wherein the electric field is applied by a DC voltage at an electric field strength of 0.25 to 5 V / cm.   The particle aggregation separation and recovery method according to any one of claims 10 to 12, wherein an inflow rate of the slurry is larger than an outflow rate of the aggregated particles.

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