JP2019136701A - Separation method, recovery method of hydrophilic particle and recovery method of hydrophobic particle - Google Patents

Abstract

To improve a separation rate and separation efficiency when separating a hydrophobic particle and a hydrophilic particle from a mixture in which the hydrophobic particle and the hydrophilic particle are mixed.SOLUTION: A separation method separating a hydrophobic particle 6 and a hydrophilic particle 5 from a mixture in which the hydrophobic particle 6 and the hydrophilic particle 5 are mixed includes: a mixing step (S1) making a slurry by mixing water and a hydrophobic liquid having larger specific gravity than water in the mixture; and a separation step (S2) moving the hydrophilic particle 5 in a water phase 1 while separating the slurry generated in the mixing step to the water phase 1 and a hydrophobic liquid phase 2 and separating the hydrophobic particle 6 from the hydrophilic particle 5 by moving the hydrophobic particle 6 to the hydrophobic liquid phase 2.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a separation method for quickly and efficiently separating hydrophobic particles and hydrophilic particles from a mixture of hydrophobic particles and hydrophilic particles, and hydrophilic particles using the separation method. The present invention relates to a collection method and a method for collecting hydrophobic particles.

Fly ash generated during power generation at a coal-fired thermal power plant or the like is recycled into concrete raw materials, building material raw materials, cement raw materials, and the like. However, fly ash contains unburned carbon, which is a carbon component left unburned, in ash composed of metal oxides such as Al ₂ O ₃ and SiO ₂ . For this reason, in order to improve the quality of the recycled fly ash, it is preferable to separate and remove unburned carbon contained in the fly ash.

  As a method for separating unburned carbon in fly ash, for example, an electrostatic separation method or a flotation method is known. The electrostatic separation method is a method in which fly ash is introduced into parallel plate electrodes in a dry state to attract and separate charged unburned carbon toward the positive electrode side. In addition, the flotation method is to attach unburned carbon particles to micro air generated using a foaming agent in a slurry of fly ash through a scavenger such as kerosene. It is a method of floating and separating.

  For example, Patent Document 1 discloses a method of removing unburned carbon in fly ash by flotation. In the flotation method of Patent Document 1, first, the fly ash that has been slurried by adding water is stirred to generate active energy on the surface of the unburned carbon particles, thereby making the unburned carbon particles oleophilic. (Hydrophobic). Next, a trapping agent such as kerosene and light oil and a foaming agent are added to the slurry containing the oleophilic unburnt carbon, and the trapping agent is attached to the unburned carbon and unburned carbon is generated in the generated bubbles. Flotation with the attached. By such a flotation method, a mixture of unburned carbon (specific gravity: 1.3 to 1.5) which is hydrophobic particles and metal oxide (specific gravity: 2.4 to 2.6) which is hydrophilic particles. Unburnt carbon is separated from some fly ash.

JP 2007-167825 A

  However, the flotation method in which the unburned carbon contained in the fly ash is floated by adhering to the bubbles as described in Patent Document 1 has a problem that the separation speed is slow and the separation efficiency is poor.

  Specifically, in the flotation method described in Patent Document 1, as shown in FIG. 18, water in which many metal oxide 102 particles are floating in a state where water and fly ash are mixed and stirred. In the phase 105, the particles of the unburned carbon 101 adhere to the fine bubbles 103 through the trapping agent 104, and the unburned carbon 101 rises in the aqueous phase 105 together with the bubbles 103. At this time, the unburned carbon 101 may be peeled off from the bubbles 103, and the unburned carbon 101 gradually rises while repeating rising and settling in the aqueous phase 105 and collects in the surface layer portion of the aqueous phase 105. For this reason, since the separation rate of the unburned carbon 101 is slow, in order to separate the unburned carbon 101 from the metal oxide 102 and reduce the content of the unburned carbon 101 to a target value or less, for example, about 1 hour. It will take a long time.

  In the above flotation method, the separation efficiency of the unburned carbon 101 is affected by the particle size of the unburned carbon 101, the degree of hydrophobicity (which depends on the type of coal used), the presence form of the unburned carbon 101, and the like. Receive a lot. For example, if the particles of the unburned carbon 101 are large, not only the unburned carbon 101 becomes difficult to adhere to the bubbles 103 due to the weight of the unburned carbon 101 but also it is difficult to float in the water phase 105. Furthermore, when the unburned carbon 101 is in the form of being bitten into the metal oxide 102, the surface portion of the unburned carbon 101 to which the bubbles 103 can adhere becomes small, so the unburned carbon 101 is difficult to adhere to the bubbles 103. Become. Due to these causes, the separation rate of the unburned carbon 101 is reduced, the separation efficiency of the unburned carbon 101 is deteriorated, the content rate of the unburned carbon 101 in the mixture cannot often be lowered to the target value, and the processing cost is also increased. it was high.

  In the above, the problem in the case of flotation of unburned carbon from fly ash which is a mixture of unburned carbon (hydrophobic particles) and metal oxide (hydrophilic particles) has been described. Similar problems can arise even when separating each particle from a mixture of hydrophilic particles.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to separate the hydrophobic particles and the hydrophilic particles from the mixture of the hydrophobic particles and the hydrophilic particles. It is to improve the separation efficiency.

In order to solve the above problems, according to one aspect of the present invention,
In a separation method for separating hydrophobic particles and hydrophilic particles from a mixture of hydrophobic particles and hydrophilic particles,
A mixing step in which the mixture is mixed with water and a hydrophobic liquid having a specific gravity greater than that of the water to form a slurry; and
While separating the slurry generated in the mixing step into an aqueous phase and a hydrophobic liquid phase, the hydrophilic particles are moved to the aqueous phase, and the hydrophobic particles are moved to the hydrophobic liquid phase. A separation step of separating the hydrophobic particles and the hydrophilic particles;
A separation method is provided comprising:

  In the separation step, the slurry is allowed to stand in a separation device, thereby utilizing the difference in specific gravity so that the slurry includes the aqueous phase containing the hydrophilic particles and the hydrophobic liquid containing the hydrophobic particles. You may make it isolate | separate into a phase.

  You may make it repeat the combination of the said mixing process and the said separation process N steps (N is an integer greater than or equal to 2) by a countercurrent type multistage continuous process.

N is an integer greater than or equal to 3,
In the first stage, the mixture and the water are charged,
The hydrophobic liquid is charged in the mixing step of the Nth stage,
the aqueous phase containing the hydrophilic particles and the remaining hydrophobic particles separated in the separation step in the nth stage (n is an integer of 1 or more and N-2 or less), and the separation process in the (n + 2) th stage. The separated hydrophobic particles and the hydrophobic liquid phase containing the remaining hydrophilic particles may be mixed and slurried in the mixing step of the (n + 1) th stage.

A cleaning step of removing the hydrophilic particles remaining in the hydrophobic liquid phase including the hydrophobic particles separated in the separation step of the first stage;
The washing step includes
A washing mixing step of adding the water to the hydrophobic liquid phase containing the hydrophobic particles separated in the separation step in the first stage and the remaining hydrophilic particles, and mixing to make a slurry;
While separating the slurry produced in the mixing step for washing into an aqueous phase and a hydrophobic liquid phase, the remaining hydrophilic particles are moved to the aqueous phase, whereby the hydrophobic particles and the remaining hydrophilic particles are moved. A separation step for washing to separate the functional particles;
May be included.

  You may make it repeat the combination of the said mixing process for washing | cleaning of the said washing | cleaning process, and the said separation process for washing | cleaning M steps (M is an integer greater than or equal to 2).

A first recovery step of separating the water from the aqueous phase containing the hydrophilic particles separated in the separation step, and collecting the hydrophilic particles;
A second recovery step of separating the hydrophobic liquid from the hydrophobic liquid phase containing the hydrophobic particles separated in the separation step, and collecting the hydrophobic particles;
Further including
The water separated in the first recovery step and the hydrophobic liquid separated in the second recovery step may be reused in the mixing step.

In the first recovery step,
The hydrophobic liquid remaining in the aqueous phase is removed by subjecting the aqueous phase containing the hydrophilic particles separated in the separation step to at least one of heating and decompression. You may do it.

  You may make it further include the magnetic separation process which adsorb | sucks and isolate | separates the magnetic material mixed in the said mixture using a magnet.

The hydrophobic liquid is a hydrophobic organic solvent,
The specific gravity of the hydrophobic organic solvent may be more than 1.05 and smaller than the specific gravity of the hydrophobic particles.

The hydrophobic liquid is a hydrophobic organic solvent,
The boiling point of the hydrophobic organic solvent may be 40 ° C. or higher and 150 ° C. or lower under atmospheric pressure.

The hydrophobic liquid is a hydrophobic organic solvent,
The boiling point of the hydrophobic organic solvent may be 40 ° C. or higher and 95 ° C. or lower under atmospheric pressure.

The hydrophilic particles are metal oxides,
The hydrophobic particles may be coke powder or coal powder.

  The mixture may be fly ash.

  You may make it further include the grinding | pulverization process which performs a grinding | pulverization process with respect to the said fly ash before the said isolation | separation process.

  In the pulverization step, at least one of a hydrophobic liquid and water and the fly ash are mixed to produce a mixed liquid, and the carbon particles as the hydrophobic particles contained in the mixed liquid are pulverized using beads. You may do it.

  The bead may have a diameter of 1 mm or less.

In order to solve the above problem, according to another aspect of the present invention,
There is provided a method for recovering hydrophilic particles, wherein the hydrophilic particles are recovered from the aqueous phase containing the hydrophilic particles separated using the separation method.

In order to solve the above problem, according to another aspect of the present invention,
There is provided a method for recovering hydrophilic particles, which recovers the aqueous phase containing the hydrophilic particles separated by using the separation method.

In order to solve the above problem, according to another aspect of the present invention,
There is provided a method for recovering hydrophobic particles, wherein the hydrophobic particles are recovered from the hydrophobic liquid phase containing the hydrophobic particles separated using the separation method.

  As described above, according to the present invention, it is possible to improve the separation speed and separation efficiency when separating hydrophobic particles and hydrophilic particles from a mixture of hydrophobic particles and hydrophilic particles.

In the separation method which concerns on the 1st Embodiment of this invention, it is a schematic diagram which shows the state of the liquid mixture immediately after mixing and stirring water and a hydrophobic organic solvent to the mixture containing a hydrophobic particle and a hydrophilic particle. In the separation method which concerns on this embodiment, it is a schematic diagram which shows an example of the state after leaving a liquid mixture still for about 1 to 30 seconds. In the separation method which concerns on this embodiment, it is a schematic diagram which shows an example of the state after leaving a liquid mixture still for 30 seconds or more. In the separation method which concerns on this embodiment, it is a schematic diagram which shows another example of the state after leaving a liquid mixture still for 30 seconds or more. Is a graph showing the relationship between the slurry concentration C _S and the slurry specific gravity d _S of the aqueous phase. And particle diameter phi _P of the hydrophilic particle is a graph showing the relationship between the apparent specific gravity d _P water coating particles. It is a schematic diagram which shows the particle separation apparatus which concerns on the same embodiment, and a single stage continuous process using the same. It is a schematic diagram which shows the particle separation apparatus which concerns on the example of a change of the embodiment, and a single stage continuous process using the same. It is a schematic diagram which shows the crossflow type separation apparatus which concerns on the same embodiment. It is a schematic diagram which shows the upflow type separation apparatus which concerns on the example of a change of the embodiment. It is a schematic diagram which shows the countercurrent type two-stage continuous process using the particle | grain separator which concerns on the 2nd Embodiment of this invention. It is process drawing which shows the separation method by the N-stage countercurrent type multistage continuous process which concerns on the same embodiment. It is process drawing which shows the separation method by a countercurrent type multistage continuous process which added the washing | cleaning process which concerns on the embodiment. It is process drawing which shows the separation method by the countercurrent type multistage continuous process which implements the washing | cleaning process which concerns on the same embodiment in multistage. It is a schematic diagram which shows the countercurrent type two-stage continuous process including the magnetic separation process which concerns on the 3rd Embodiment of this invention. It is a graph which shows the change of the content rate of the hydrophobic particle in each step | level of the countercurrent type | mold three-stage continuous process which concerns on the Example of this invention. It is a graph which shows the change of the content rate of the hydrophobic particle in each stage of the countercurrent type | mold four-stage continuous process including the washing | cleaning process which concerns on the Example of this invention. It is a graph which shows the change of the content rate of the hydrophobic particle in each stage of the countercurrent type | mold four-stage continuous process including the washing | cleaning process which concerns on the Example of this invention. It is a schematic diagram which shows the floating principle of the unburned carbon in the conventional flotation method.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[1. Target of separation method]
First, a mixture to be treated by the separation method according to the first embodiment of the present invention, hydrophilic particles, hydrophobic particles, a hydrophobic liquid, and the like will be described.

Table 1 shows an example of a processing object (mixture of hydrophilic particles and hydrophobic particles) of the separation method according to the present embodiment. As shown in Table 1, for example, the fly ash and blast furnace gas ash of the processing object are particles of metal oxide (Al ₂ O ₃ , SiO ₂ , Fe ₂ O _3, etc.) that are hydrophilic particles, and hydrophobic It is a mixture in which unburned carbon particles (coal powder, etc.), which are particles, are mixed. Further, in the coal to be treated, particles of metal oxide (Al ₂ O ₃ , SiO _2, etc.) that are hydrophilic particles are mixed into carbon particles (coke powder, coal powder, etc.) that are hydrophobic particles. It is a mixture.

  More specifically, fly ash often contains about 90 to 95% by mass of oxide particles that are hydrophilic particles and about 5 to 10% by mass of unburned carbon that is hydrophobic particles. The particle size of fly ash is about 1 to 200 μm. Some particles in the fly ash exist as particles in which carbon and metal oxide are integrated.

  Blast furnace gas ash is a collection of raw material dust charged in the blast furnace, dust generated by metallurgical reaction in the blast furnace, in other words, blast furnace dust ash, and 15 to 30% by mass of carbon as a component. Including. The particle size of the blast furnace gas ash is about 1 to 200 μm. Examples of components of blast furnace gas ash are shown in Table 2 below. Blast furnace gas ash contains coke-derived carbon as hydrophobic particles. Moreover, the blast furnace gas ash contains a plurality of types of metal oxides shown in Table 2 as hydrophilic particles. Some particles in the blast furnace gas ash exist as particles in which carbon and metal oxide are integrated.

  In the present embodiment, hydrophilic particles (for example, metal oxide) and hydrophobic particles (for example, carbon) are separated and collected from the mixture of hydrophilic particles and hydrophobic particles as described above. As a result, the metal oxides are reused, for example, as raw materials for concrete (aggregates, admixtures, etc.), raw materials for building materials, etc., and carbon is reused as coal for power generation, iron making, cement clinker, etc. Used. At this time, if the carbon content in the recovered metal oxide can be reduced to, for example, 3% by mass or less, the loss on ignition in the quality stipulation of fly ash type I for concrete described in JIS A6201-2008 ( It is within the range of the unburned carbon content), and by adjusting other quality regulations such as fineness, it becomes possible to recycle metal oxide as a fly ash for concrete for a fee. Also extend.

  Next, the hydrophobic liquid used in the separation method according to this embodiment will be described. The hydrophobic liquid is a liquid having hydrophobicity, that is, a liquid having a property of low affinity for water (difficult to dissolve in water or difficult to mix with water). The hydrophobic liquid is, for example, a liquid having a solubility in water at 20 ° C. of 0 g / L or more and 5.0 g / L or less. In addition, hydrophobicity in this specification is a property including lipophilicity. The hydrophobic liquid may be, for example, a hydrophobic organic solvent (hereinafter referred to as “hydrophobic organic solvent”), various oils, or the like. Hydrophobic liquid has low affinity for water, so when the liquid mixture obtained by mixing and stirring the hydrophobic liquid and water is allowed to stand, an aqueous phase mainly composed of water and a hydrophobic liquid (for example, a hydrophobic organic solvent) are separated. It is separated into two phases of a hydrophobic liquid phase (for example, a hydrophobic organic solvent phase) as a main component.

  Furthermore, in this embodiment, a liquid having a specific gravity greater than that of water, that is, a liquid having a specific gravity greater than 1, is used as the hydrophobic liquid. By using a hydrophobic liquid having a specific gravity greater than that of water, if the mixture of the hydrophobic liquid and water is stirred and left standing, the upper aqueous phase and the lower hydrophobic liquid phase will differ depending on the specific gravity difference between the two liquids. And separated.

  Table 3 shows examples of hydrophobic liquids used in the separation method according to this embodiment. As shown in Table 3, the hydrophobic liquid may be, for example, a fluorine-based, bromine-based or chlorine-based organic solvent, or may be an oil such as silicone oil. All of the hydrophobic liquids exemplified in Table 3 have a specific gravity of more than 1, a solubility in water of 5 g / L or less, and are hydrophobic.

  The specific gravity of the hydrophobic liquid is preferably more than 1.05. As a result, after mixing water (specific gravity 1) and the hydrophobic liquid and allowing to stand, for example, the water phase and the hydrophobic liquid phase can be rapidly separated in a short time of about 1 to 30 seconds. Can be increased. The specific gravity of the hydrophobic liquid is preferably smaller than the specific gravity of the hydrophobic particles (for example, 1.2 to 1.8). As a result, in the process of separating and recovering the hydrophobic particles from the hydrophobic liquid phase containing the hydrophobic particles, the hydrophobic liquid and the hydrophobic particles can be efficiently separated using a solid-liquid separation device. Details thereof will be described later.

  Next, hydrophilic particles and hydrophobic particles will be described. The hydrophilic particles are particles having an affinity for water and have a property of being easily mixed with water as compared with the hydrophobic liquid. On the other hand, the hydrophobic particles are particles having an affinity for the hydrophobic liquid and have a property of being easily mixed in the hydrophobic liquid rather than water. Therefore, in the mixed liquid of water and hydrophobic liquid, the hydrophilic particles move from the hydrophobic liquid phase to the aqueous phase and are mainly dispersed in the aqueous phase. On the other hand, the hydrophobic particles move from the aqueous phase to the hydrophobic liquid phase and are mainly dispersed in the hydrophobic liquid phase.

The hydrophilic particles are, for example, metal oxide particles such as Al ₂ O ₃ , SiO ₂ , and Fe ₂ O ₃ as shown in Table 1 above, but other materials can be used as long as they are hydrophilic particles. The particles may also be On the other hand, the hydrophobic particles are, for example, coal powder such as unburned carbon, coke powder, plastic powder or the like, but may be particles of other materials as long as they are hydrophobic particles. The particle diameter of the hydrophilic particles targeted by the present embodiment is 500 μm or less, and preferably 200 μm or less. The particle diameter of the hydrophobic particles is 500 μm or less. Details will be described later.

The content ratio of the hydrophilic particles and the content ratio of the hydrophobic particles contained in the mixture that is the treatment target are not particularly limited. For example, the content ratio of the hydrophilic particles in the mixture is 5 to 97% by mass. The content of the hydrophobic particles may be about 3 to 95% by mass. However, the total content of the hydrophilic particles and the hydrophobic particles 6 is 100% by mass or less. When the hydrophobic particles are carbon, for example, when the mixture is fly ash or blast furnace gas ash, the ignition loss rate can be measured, and the value can be used as the content of the hydrophobic particles. The ignition loss rate is a mass reduction rate when a sample dried at 105 ° C. is held for 15 minutes or more in an atmosphere atmosphere furnace set at 975 ° C. Further, when the hydrophobic particles are plastic, for example, polyethylene terephthalate powder or vinyl chloride resin powder, the carbon content in the sample is measured by, for example, the combustion-infrared absorption method, and each plastic is determined from the carbon content. In accordance with the composition, it can be converted into the content of hydrophobic particles. Incidentally, the combustion - IR absorption method, a sample covered with a combustion improver (pure iron powder and tungsten powder) is heated and burned in a high frequency furnace, a carbon component in the sample to the CO ₂ is gasified, generated CO _This is a method for measuring the carbon content in a sample from _two quantities.

Moreover, as shown in Table 1, the specific gravity of the hydrophilic particles is, for example, 2.4 to 2.6 (Al ₂ O ₃ , SiO ₂ ), 4 to 5 (Fe ₂ O ₃ ). The specific gravity of the hydrophobic particles is, for example, 1.2 to 1.8. When the hydrophobic particles are carbon particles, the specific gravity of the carbon particles is, for example, 1.3 to 1.5. Thus, even if the specific gravity of the hydrophobic particles is smaller than the specific gravity of the hydrophilic particles, according to the separation method according to this embodiment, the hydrophilic particles are separated from the upper water phase as described later. And the hydrophobic particles are allowed to settle in the lower hydrophobic liquid phase, and both particles can be wet-separated quickly and efficiently. In the present specification, the specific gravity of the particle is the specific gravity (true specific gravity) of the particle itself and not the particle bulk specific gravity.

[2. Overview of separation method]
Next, an outline of a method for separating hydrophilic particles and hydrophobic particles from the mixture according to the present embodiment will be described.

  The separation method according to the present embodiment separates hydrophilic particles and hydrophilic particles from a mixture (for example, fly ash) in which hydrophilic particles (for example, metal oxide) and hydrophobic particles (for example, unburned carbon) are mixed. It is a wet separation method.

  In this separation method, water is used as an extractant for hydrophilic particles, and a hydrophobic liquid having a specific gravity greater than that of water is used as an extractant for hydrophobic particles. And the said water and hydrophobic liquid are mixed and stirred in the mixture (solid content) of a process target, and the liquid mixture (1st slurry) in which the mixture was disperse | distributed is produced | generated (mixing process). Next, the mixed liquid is allowed to stand in a separation apparatus (for example, a settler such as a precipitation tank or a stationary tank), and the above mixed liquid is removed from the upper aqueous phase by utilizing the specific gravity difference between water and the hydrophobic liquid. The hydrophilic particles are moved to the aqueous phase and the hydrophobic particles are moved to the hydrophobic liquid phase (separation step). In the case of processing a small amount of the mixture, the mixed solution may be allowed to stand and be separated into an aqueous phase and a hydrophobic liquid phase by using various containers such as a beaker instead of a settler as a separation device. it can. Further, the hydrophilic particles are separated and recovered from the aqueous phase (second slurry) separated in the separation step (first recovery step), and the hydrophobic liquid phase (third slurry) separated in the separation step is collected. ) To separate and recover the hydrophobic particles (second recovery step). Thereby, hydrophilic particles and hydrophobic particles can be quickly and efficiently separated, and hydrophilic particles and hydrophobic particles having a high content can be recovered and reused. The separation method will be described in detail below.

[2.1. Separation principle and effect]
Here, the principle of the separation method according to the present embodiment will be described with reference to FIGS. 1 and 2. The specific gravity of hydrophobic particles and hydrophilic particles is greater than 1. In addition, a hydrophobic organic solvent is used as the hydrophobic liquid. In the following, “hydrophobic organic solvent” is sometimes referred to as “hydrophobic solvent” or simply “solvent”, and “hydrophobic organic solvent phase” is sometimes referred to as “hydrophobic solvent phase” or simply “solvent phase”. is there.

  FIG. 1 shows that immediately after water and a hydrophobic organic solvent are added to a mixture containing hydrophobic particles and hydrophilic particles and vigorously stirred, the mixture (first slurry) of the mixture, water and hydrophobic organic solvent is on the upper side. The water phase 1 and the lower hydrophobic organic solvent phase 2 are separated. In FIG. 2, the liquid mixture was separated into an aqueous phase 1 containing hydrophilic particles 5 and a hydrophobic organic solvent phase 2 containing hydrophobic particles 6 by standing for about 1 to 30 seconds after the stirring. Indicates the state.

  As shown in FIG. 1, immediately after stirring of the mixed solution, the aqueous phase 1 may be referred to as a hydrophobic organic solvent droplet 3 (hereinafter referred to as “solvent droplet 3” or simply “droplet 3”). )) And water droplets 4 are present in the hydrophobic organic solvent phase 2. Hydrophobic particles 6 are contained inside the solvent droplets 3, and the hydrophobic particles 6 are attached to the surfaces of the solvent droplets 3. On the other hand, hydrophilic particles 5 are contained inside the water droplet 4, and the hydrophilic particles 5 are attached to the surface of the water droplet 4. Although depending on the stirring strength of the mixed liquid, the solvent droplet 3 and the water droplet 4 often have a diameter of 0.5 mm or more, for example.

  The specific gravity of water is 1, and the specific gravity of the hydrophobic organic solvent is 1.05 to 1.8. Although there is an influence of specific gravity and viscosity of water and a hydrophobic organic solvent, the sedimentation speed of the solvent droplet 3 (diameter 0.5 mm) in the aqueous phase 1 is very high, for example, about 0.05 to 0.1 m / sec. The sedimentation rate of the hydrophobic particles 6 adhering to the solvent droplet 3 is also large. Further, although there is an influence of the specific gravity and viscosity of water and the hydrophobic organic solvent, the rising speed of the water droplet 4 (diameter 0.5 mm) in the hydrophobic organic solvent phase 2 is, for example, about 0.1 to 0.2 m / sec, which is very large, and the flying speed of the hydrophilic particles 5 adhering to the water droplet 4 is also high.

  In the aqueous phase 1, most of the hydrophobic particles 6 adhere to the solvent droplet 3 or are taken into the solvent droplet 3. However, there are few hydrophobic particles 6 in the aqueous phase 1 that could not adhere to the solvent droplets 3. A liquid film of a hydrophobic organic solvent having a specific gravity greater than that of water is thinly attached (for example, about 5 to 20 μm) on the surface of the hydrophobic particles 6. For this reason, the apparent specific gravity of the hydrophobic particles 6 to which the liquid film of the hydrophobic organic solvent adheres is an intermediate specific gravity between the specific gravity of the hydrophobic solvent and the specific gravity of the hydrophobic particles 6. Therefore, the apparent particle diameter (including the liquid film thickness) is increased by the liquid film of the hydrophobic organic solvent adhering to the surface of the hydrophobic particles 6. For this reason, in the aqueous phase 1, the hydrophobic particles 6 to which the hydrophobic organic solvent adheres are liable to settle and the sedimentation speed increases.

  On the other hand, the hydrophobic organic solvent phase 2 has a small amount of hydrophilic particles 5 that could not adhere to the water droplets 4. A thin water film (for example, about 5 to 20 μm) is attached to the surface of the hydrophilic particles 5. Since the specific gravity of water is smaller than the specific gravity of the hydrophobic organic solvent, the apparent specific gravity of the hydrophilic particles 5 (hereinafter sometimes referred to as “water-coated particles 5”) coated with the water coating is hydrophilic particles. It is smaller than the specific gravity of 5 itself. For this reason, when the thickness of the attached water film is constant, if the apparent particle diameter of the water film particle 5 (particle diameter obtained by combining the hydrophilic particle 5 and the water film) is small, the water film particle 5 becomes hydrophobic. On the other hand, when the apparent particle diameter is large, the water-coated particles 5 in the hydrophobic organic solvent phase 2 settle in the hydrophobic organic solvent phase 2.

  As described above, in the separation method according to this embodiment, in the aqueous phase 1 shown in FIG. 1, the solvent droplet 3 to which the hydrophobic particles 6 are attached and the hydrophobic particles to which the liquid film of the hydrophobic organic solvent is attached. 6 quickly settles from the aqueous phase 1 to the hydrophobic organic solvent phase 2. Furthermore, in the hydrophobic organic solvent phase 2 shown in FIG. 1, the water droplets 4 to which the hydrophilic particles 5 are adhered and the hydrophilic particles 5 to which the water film is adhered are rapidly transferred from the hydrophobic organic solvent phase 2 to the aqueous phase 1. Surface.

  Therefore, in this embodiment, after mixing and stirring the mixture to be separated, water and the hydrophobic organic solvent, the mixture is allowed to stand, for example, in a short time of about 1 to 30 seconds. As shown in FIG. 2, the mixed solution is separated into an upper aqueous phase 1 and a lower hydrophobic organic solvent phase 2. Accompanying the separation of the upper and lower two liquid phases, the hydrophobic particles 6 settle at a large sedimentation speed and move to the hydrophobic organic solvent phase 2. On the other hand, the hydrophilic particles 5 float at a high flying speed and move quickly to the water phase 1. For this reason, the hydrophilic particles 5 and the hydrophobic particles 6 can be quickly separated.

  Here, in the conventional flotation method described in Patent Document 1 described above, a large amount of a hydrophobic organic solvent is not used as in the present embodiment, but a slightly collecting agent and a foaming agent such as kerosene and light oil are used. The hydrophobic particles (unburned carbon 101) having a relatively small specific gravity were attached to the bubbles 103 and floated (see FIG. 18). At this time, the addition amount of the scavenger and the foaming agent added to the water is as small as several mass% with respect to the mass of the fly ash. However, in such a conventional method, when the particle diameter of the unburned carbon 101 is large, even if the unburned carbon 101 adheres to the bubbles 103, the unburned carbon 101 is easily separated from the bubbles 103. In this conventional method, air bubbles are attached to the unburned carbon 101 to be settled and forced to rise against gravity. For this reason, the ascent rate is very slow, and it takes about 1 hour to reduce the unburned carbon content to a low content (for example, 3% by mass or less), as well as recovered hydrophilic particles (metal There is a problem that the separation efficiency is poor, for example, the content of unburned carbon 101 in the oxide) may not be reduced below the target value (for example, 3% by mass or less).

  In contrast, in the separation method according to the present embodiment, a hydrophobic organic solvent having a specific gravity greater than that of water is used in a large amount as much as water, and the separation action between the hydrophobic organic solvent and water is used. The feature is that the hydrophilic particles 5 and the hydrophobic particles 6 are separated. That is, by reliably bringing a large amount of the hydrophobic organic solvent into contact with the hydrophobic particles 6, the hydrophobic particles 6 having a relatively small specific gravity (for example, specific gravity: 1.3 to 1.5) are removed from the solvent droplet 3. And the like, and is taken into the hydrophobic organic solvent phase 2 (for example, specific gravity: more than 1.05, 1.8 or less). On the other hand, hydrophilic particles 5 having a relatively large specific gravity (for example, specific gravity: 2.4 to 2.6) are levitated together with water droplets 4 and the like, and taken into the upper aqueous phase 1 (specific gravity: 1). Even if the specific gravity of the hydrophobic particles 6 is larger than the specific gravity of the hydrophilic particles 5, the hydrophilic particles 5 and the hydrophobic particles 6 are used by using water and a hydrophobic organic solvent in the same amount as described above. Can be separated.

  Furthermore, in the separation method according to the present embodiment, the hydrophobic organic solvent used in the separation step is recovered by a subsequent recovery step such as solid-liquid separation or distillation treatment as described later, and re-applied to the mixing step and separation step. Use. As a result, a large amount of the hydrophobic organic solvent can be circulated and used in the mixing step and the separation step, and therefore, the contact probability between the hydrophobic particles 6 and the hydrophobic organic solvent is very high in the step. Furthermore, since the hydrophobic particles 6 having a specific gravity of greater than 1 and the hydrophobic organic solvent having a specific gravity of greater than 1 are adhered, the hydrophobic particles 6 can be more easily settled.

  Therefore, the separation method according to the present embodiment efficiently separates the hydrophobic particles 6 (for example, unburned carbon) into the hydrophobic organic solvent phase 2 as compared with the conventional flotation method described in Patent Document 1. And the ability to separate the hydrophobic particles 6 from the mixture is excellent. Therefore, the separation speed of the hydrophobic particles 6 can be greatly increased and the separation efficiency can be improved, so that the content of the hydrophobic particles 6 in the recovered hydrophilic particles 5 can be greatly reduced.

  As described above, as a result of wet separation of the hydrophilic particles 5 and the hydrophobic particles 6 using the aqueous phase 1 and the hydrophobic organic solvent phase 2, finally, as shown in FIG. 6 is hardly contained in the aqueous phase 1. For this reason, the aqueous phase 1 (second slurry containing the hydrophilic particles 5) is extracted from the upper part of the container used in the separation step and dehydrated to recover the hydrophilic particles 5 having a low content of the hydrophobic particles 6. be able to. On the other hand, the hydrophobic organic solvent phase 2 (the third slurry containing the hydrophobic particles 6) is extracted from the lower part of the container, and the hydrophobic organic solvent is subjected to solid-liquid separation, whereby the hydrophobic content of the hydrophilic particles 5 is low. The particles 6 can also be recovered.

  Although not shown in FIGS. 1 and 2, a thin surface layer of the hydrophobic organic solvent is formed above the surface layer of the water phase 1 due to surface tension at the interface between the water phase 1 and the gas phase 9. There is a case. Hydrophobic particles 6 can adhere to the surface layer of the hydrophobic organic solvent. Accordingly, when the aqueous phase 1 (second slurry containing the hydrophilic particles 5) separated in the separation step is extracted from the container, it is collected from the surface layer of the aqueous phase 1, for example, 2 to 2 It is preferable to extract the second slurry containing the hydrophilic particles 5 from a region below about 30 cm. Thereby, the hydrophobic particles 6 floating on the surface layer of the hydrophobic organic solvent formed on the upper side of the aqueous phase 1 can be prevented from being collected. Therefore, the content of the hydrophobic particles 6 in the recovered hydrophilic particles 5 can be further reduced.

[2.2. Relationship between specific gravity of aqueous phase slurry and specific gravity of hydrophobic organic solvent]
Next, referring to FIG. 3A and FIG. 3B (hereinafter sometimes collectively referred to as “FIG. 3”) and FIG. 4, an aqueous phase containing hydrophilic particles 5 suitable for realizing the separation method described above. The relationship between the specific gravity of the slurry No. 1 and the specific gravity of the hydrophobic organic solvent will be described.

  The specific gravity of the hydrophilic particles 5 in the aqueous phase 1 shown in FIG. 3 is usually larger than the specific gravity of the hydrophobic organic solvent. Nevertheless, in most cases, the hydrophilic particles 5 in the aqueous phase 1 stay in the aqueous phase 1 without sinking in the hydrophobic organic solvent phase 2.

  In particular, as shown in FIG. 3, in the separation method, the hydrophilic particles 5 dispersed in the aqueous phase 1 (that is, the slurry of water and hydrophilic particles 5) settle in the aqueous phase 1, and the aqueous phase 1 The concentration part 7 of the hydrophilic particle 5 comes to be formed in the lower part. The concentration part 7 is an area where a large number of hydrophilic particles 5 are densely present in the lower part of the aqueous phase 1. When the specific gravity of the slurry of the concentration part 7 is sufficiently smaller than the specific gravity of the hydrophobic organic solvent, the interface between the aqueous phase 1 and the hydrophobic organic solvent phase 2 becomes horizontal and becomes clear. However, when the specific gravity of the slurry of the concentration unit 7 is substantially equal to or greater than the specific gravity of the hydrophobic organic solvent phase 2, the slurry of the concentration unit 7 settles in the solvent phase 2, and the water phase 1 and the hydrophobic organic solvent phase 2 The interface with becomes unclear.

  For example, when a mixture (fly ash) mainly composed of hydrophilic particles 5 is added to a mixed liquid obtained by mixing trichlorethylene (specific gravity: 1.46) and water (specific gravity: 1) as a hydrophobic organic solvent, trichloroethylene is added. The interface between the phase (solvent phase 2) and the aqueous phase 1 becomes unclear. At this time, the average specific gravity of the slurry of the concentrated portion 7 of fly ash precipitated in the aqueous phase 1 is 1.35, which is close to the specific gravity of trichlorethylene (1.46). In the fly ash concentration section 7, in the vicinity of the interface between the aqueous phase 1 and the trichlorethylene phase, the consolidation proceeds from the interface, so that the specific gravity of the slurry in the concentration section 7 increases and is closer to the specific gravity 1.46 of trichlorethylene. Therefore, it is considered that the interface becomes unclear. In particular, as shown in FIG. 3B, as the number of hydrophobic particles 6 floating in the solvent phase 2 increases, the apparent specific gravity of the concentrated portion 7 ′ of the hydrophobic particles 6 in the solvent phase 2 becomes smaller than the specific gravity of the solvent itself, It becomes close to the apparent specific gravity of the concentrated portion 7 of the hydrophilic particles 5 in the aqueous phase 1. Therefore, the interface between the aqueous phase 1 and the solvent phase 2 becomes unclear.

Figure 4 is a graph showing the relationship between the slurry concentration C _S and the slurry specific gravity d _S of the aqueous phase 1. In FIG. 4, the range of specific gravity of the main hydrophobic organic solvent is also shown.

Here, the slurry concentration C _S [mass%] is a mass ratio of the hydrophilic particles 5 contained in the aqueous phase 1 (a slurry of water and hydrophilic particles 5), and is represented by the following formula (1). The slurry specific gravity d _S is the apparent density ρ _S [g / cm ³ ] of the aqueous phase 1 (slurry of water and hydrophilic particles 5), and the density ρ _w [g / cm ³ ] of water at the same temperature and pressure. The value obtained by division is expressed by the following equation (2).

C _S = m _P / (m _P + m _W ) (1)
d _S = ρ _S / ρ _w = (m _P + m _W ) / (V _P + V _W ) / ρ _w (2)
m _P [g]: Mass of hydrophilic particles 5 contained in aqueous phase 1 m _W [g]: Mass of water contained in aqueous phase 1 V _P [cm ³ ]: Hydrophilic particles 5 contained in aqueous phase 1 Volume V _W [cm ³ ]: volume of water contained in aqueous phase 1 ρ _S [g / cm ³ ]: apparent density of slurry of water and hydrophilic particles 5 in aqueous phase 1 ρ _w [g / cm ³ ] : Water density at the same temperature and pressure

As shown in FIG. 4, when the separation target is fly ash (specific gravity: 2.4) and the hydrophobic solvent is trichlorethylene (specific gravity: 1.46), the slurry concentration _CS becomes 54% by mass or more. The slurry specific gravity d _S becomes 1.46 or more. Therefore, if the slurry concentration _CS is less than 54% by mass, the metal oxide (hydrophilic particles 5) and water slurry (water phase 1) contained in the fly ash are contained in the trichlorethylene phase (solvent phase 2). It can be said that it does not settle. However, when fly ash and water are mixed, if the slurry concentration _CS is 54% by mass, the mixture becomes hard mud and not slurry, so that the mixing property is deteriorated and mixed with trichlorethylene. It ’s difficult.

Therefore, when using fly ash as a separation subject, since this depends on the existence form of unburned carbon in the fly ash, albeit necessary to obtain by experiment, the slurry concentration C _S is to be less than 38 wt% preferable. When the slurry concentration C _S is 38 mass percent, the decrease in the content of unburned carbon in the fly ash after treatment but rarely seen, the slurry concentration C _S, is less than 38% by weight, after treatment When the content of unburned carbon in the fly ash decreases and further becomes less than 27% by mass, the content of unburned carbon in the fly ash after treatment becomes low and constant. Thus, as the slurry concentration C _S of the aqueous phase 1 is less than 38 wt%, or adjusting the mixing ratio of the fly ash and water in the mixing step, or to select a hydrophobic organic solvent suitable density preferable.

In addition, when the separation target is blast furnace gas ash (specific gravity: 4.0) and the hydrophobic solvent is trichlorethylene (specific gravity: 1.46), the slurry concentration _CS is 42% by mass as shown in FIG. If it becomes above, the specific gravity of a slurry will be 1.46 or more. Therefore, if the slurry concentration _CS is less than 42% by mass, the metal oxide (hydrophilic particles 5) and water slurry (water phase 1) contained in the blast furnace gas ash are in the trichlorethylene phase (solvent phase 2). It can be said that does not settle.

Blast furnace gas ash is more likely to concentrate near the interface between the water phase 1 and the trichlorethylene phase (solvent phase 2) than fly ash, and the slurry specific gravity d _S in the concentration section 7 tends to increase. For this reason, since it depends on the form of unburned carbon in the blast furnace gas ash, it is necessary to obtain it by experiments, but in order to reduce the slurry specific gravity d _S in the concentration section 7, the slurry concentration C _S is less than 14% by mass. Preferably there is. When the slurry concentration C _S is 14 mass percent, although reduction of the content of unburned carbon in the blast furnace gas ash hardly seen after treatment, the slurry concentration C _S, when less than 14% by weight, after treatment the content of unburnt carbon in the blast furnace gas ash lowered, and further, the C _S is less than 7 mass%, the content of unburned carbon in the blast furnace gas in the ash after processed is constant at low.

As described above with reference to FIG. 4, the hydrophilic particles 5 settle from the aqueous phase 1 to the solvent phase 2 by selecting a hydrophobic organic solvent having a higher specific gravity as the specific gravity of the hydrophilic particles 5 is larger. And the content (slurry concentration C _S ) of the hydrophilic particles 5 in the aqueous phase 1 can be increased. In addition, when the specific gravity of the hydrophilic particle 5 is small, it is not necessary to dare to select a hydrophobic organic solvent having a small specific gravity, and the range of applicable specific gravity of the hydrophobic organic solvent can be expanded.

[2.3. Relationship between apparent particle size of hydrophilic particles and specific gravity of hydrophobic organic solvent]
Next, referring to FIG. 1 and FIG. 5, hydrophilic particles 5 (also referred to as “water-coated particles 5”) coated with a water film in a hydrophobic organic solvent phase 2 suitable for realizing the separation method described above. The relationship between the apparent particle diameter and the specific gravity of the hydrophobic organic solvent will be explained.

  As shown in FIG. 1, in the hydrophobic organic solvent phase 2, a thin water film (for example, about 5 to 20 μm) may adhere to the surface of the hydrophilic particles 5 that could not adhere to the water droplets 4. The apparent specific gravity of the hydrophilic particles 5 covered with the water film is smaller than the specific gravity of the hydrophilic particles 5 themselves. The amount of water film attached to the hydrophilic particles 5 varies depending on the thickness of the water film, the voids of the hydrophilic particles 5 and the like.

For example, FIG. 5 shows the particle diameter φ _P of the hydrophilic particles 5 and the apparent specific gravity d _P of the water coating particles 5 when a 10 μm thick water coating is attached to spherical fine particles (hydrophilic particles 5) without voids. It is a graph which shows the relationship.

Here, the apparent specific gravity d _P of the water coating particle 5 is obtained by dividing the apparent density ρ _P [g / cm ³ ] of the water coating particle 5 by the density ρ _w [g / cm ³ ] of water at the same temperature and pressure. Which is expressed by the following formula (3).

d _P = ρ _P / ρ _w = (m _P + m _C ) / (V _P + V _C ) / ρ _w (3)
m _P [g]: Mass of the hydrophilic particle 5 m _C [g]: Mass of the water film attached to the hydrophilic particle 5 V _P [cm ³ ]: Volume of the hydrophilic particle 5 V _C [cm ³ ]: Hydrophilic Volume of water coating adhered to conductive particles 5 ρ _P [g / cm ³ ]: Apparent density of water coating particles 5 ρ _w [g / cm ³ ]: Density of water at the same temperature and pressure

As shown in FIG. 5, as the particle diameter phi _P of the hydrophilic particles 5 is small, since the thickness t of the water film increases to the particle diameter phi _P of the hydrophilic particles 5, the apparent specific gravity of the water film particles 5 d _P becomes smaller. When the apparent specific gravity d _P of the water coating particle 5 is smaller than the specific gravity of the hydrophobic organic solvent, the water coating particle 5 floats in the solvent phase 2 and moves to the water phase 1.

Accordingly, a hydrophobic organic solvent having an appropriate specific gravity is selected according to the particle diameter φ _{P of} the hydrophilic particles 5, the thickness t of the water coating, the degree of voids in the hydrophilic particles 5, and the like. it is preferred that the specific gravity d _P is adjusted to be smaller than the specific gravity of the hydrophobic organic solvent. When it is difficult to directly measure the thickness t of the water film, for example, 0.5 to 1 g of the hydrophilic particles 5 is put into a mixed solution composed of 80 ml of water and 20 ml of the hydrophobic organic solvent in a measuring cylinder with a stopper, At that time, it is preferable to select a hydrophobic organic solvent in which most of the hydrophilic particles 5 do not settle in the hydrophobic organic solvent phase 2. Thereby, in the separation step, the water-coated particles 5 can float from the solvent phase 2 to the aqueous phase 1 and can stay in the aqueous phase 1, and the hydrophilic particles 5 can be retained in the hydrophobic organic solvent and the hydrophobic particles 6. Can be separated quickly and efficiently.

[2.4. Preferred range of particle diameter or specific gravity of particles]
Next, the particle diameter or specific gravity range suitable for realizing the separation method will be described with reference to FIG. As shown in FIG. 3, in the state where the hydrophilic particles 5 settle in the aqueous phase 1 and reach the interface between the aqueous phase 1 and the hydrophobic solvent phase 2, the hydrophilic particles 5 have buoyancy and interfacial tension. And gravity act. The interfacial tension acts as an energy barrier that inhibits the hydrophilic particles 5 from moving from one phase 1 to the other phase 2 at the interface. It can be said that the balance of these forces determines which phase the hydrophilic particles 5 move to. When the particle diameter of the hydrophilic particles 5 is large or the specific gravity of the hydrophilic particles 5 is large relative to the specific gravity of water, the gravity exceeds the total of the buoyancy and interfacial tension acting on the hydrophilic particles 5, It is considered that the particles 5 move from the aqueous phase 1 to the solvent phase 2 through the interface. In this case, the separation efficiency between the hydrophilic particles 5 and the hydrophobic particles 6 decreases. From this viewpoint, it is preferable to remove the hydrophilic particles 5 having such a large particle diameter or specific gravity as to pass through the interface and move to the solvent phase 2 before the separation treatment. For example, the particle diameter of the hydrophilic particles 5 contained in the mixture before the separation treatment may be 500 μm or less, and preferably 200 μm or less.

  As shown in FIG. 3B, the same applies to the hydrophobic particles 6 that floated in the hydrophobic solvent phase 2 and reached the interface. The particle diameter of the hydrophobic particles 6 is large to the extent that the buoyancy exceeds the sum of gravity and interfacial tension acting on the hydrophobic particles 6, or is hydrophobic with respect to the specific gravity of the hydrophobic solvent (especially than the specific gravity of water). When the specific gravity of the conductive particles 6 is small, it is considered that the particles 6 move from the solvent phase 2 to the aqueous phase 1 through the interface. From this viewpoint, it is preferable to remove the hydrophobic particles 6 having such a large particle diameter or small specific gravity as to pass through the interface and move to the aqueous phase 1 before the separation treatment. For example, the particle diameter of the hydrophobic particles 6 contained in the mixture before the separation treatment may be 500 μm or less, and preferably 200 μm or less. The maximum particle diameter of the hydrophilic particles 5 or the hydrophobic particles 6 can be controlled by sieving with a sieve or classification with a cyclone.

[3. Improved separation by grinding process]
Some mixtures in which hydrophobic particles and hydrophilic particles coexist partially integrate hydrophobic particles and hydrophilic particles. For example, when the mixture is fly ash, the oxide particles in the fly ash are substantially spherical particles mainly composed of Al ₂ O ₃ and SiO ₂ . Many oxide particles are present outside the unburned carbon particles. However, the unburned carbon particles in the fly ash are porous, and some of the oxide particles have entered the pores in the unburned carbon particles. The ratio of the oxide particles entering the unburned carbon particles may reach the same amount as the mass of the unburned carbon.

  Above [2. Separation of the hydrophobic particles and the hydrophilic particles proceeds only to a certain extent only by the separation method shown in the outline of the separation method], but there are many portions where the hydrophobic particles and the hydrophilic particles are integrated in the mixture. Separation deteriorates. For example, when the mixture is fly ash, the unburned carbon content in the hydrophilic particles separated and recovered is often 3% by mass or less, but sometimes exceeds 3% by mass and varies. The unburned carbon content in the hydrophobic particles separated and recovered is often 50% by mass or more, but the content varies greatly. The cause of these fluctuations is that unburned carbon particles and oxide particles are partially integrated in the fly ash. If there are many integrated parts, the separability deteriorates. Therefore, [2. By separating the target mixture before the separation by the method shown in Outline of Separation Method], the separation property between the hydrophobic particles and the hydrophilic particles is improved.

  As the pulverization method, the slurry-like mixture is pulverized by a mill using a pulverizing medium such as balls and beads, pulverized by colliding with a high-speed shear blade of a high-shear homogenizer, or ultrasonically by an ultrasonic pulverizer. Any one of irradiating and pulverizing may be used. The optimum method may be selected by observing the hardness of each of the hydrophilic particles and the hydrophobic particles in the mixture or the integration state of both particles and finally testing the grinding method.

  For example, when the mixture is fly ash, the unburned carbon particles that are porous are easily pulverized, but the oxide particles are spherical and dense and difficult to pulverize. Therefore, by adopting a grinding process using beads, brittle unburned carbon particles can be efficiently ground in a short time without destroying hard oxide particles contained in fly ash. In order to pulverize unburned carbon particles having a smaller particle diameter between approximately spherical oxide particles, the larger the bead diameter (hereinafter referred to as bead diameter), the harder approximately spherical oxide particles are pulverized. The possibility of collision between the beads and unburned carbon particles with a small particle size must be reduced. On the other hand, the smaller the bead diameter, in other words, the larger the curvature of the bead, the more the bead can come into contact with unburned carbon particles with a smaller particle diameter without colliding with hard, substantially spherical oxide particles. Therefore, it can be said that the bead diameter is preferably 1 mm or less.

  Therefore, when the mixture is fly ash, beads having a diameter of 1 mm or less are used, and pulverization treatment for about 1 second to 5 minutes is performed on the fly ash made into a slurry, so that only unburned carbon particles are mainly used. Can be crushed. At this time, the oxide particles that have entered the pores of the unburned carbon particles are released from the unburned carbon particles. For the fly ash slurry after the pulverization treatment as described above, [2. By applying the separation method shown in the Outline of Separation Method], the unburned carbon content in the separated and recovered hydrophilic particles is stable to 1% by mass or less, and in the separated and collected hydrophobic particles The unburned carbon content is 70% by mass or more and less than 95%, and is stabilized.

[4. Single-stage continuous process]
Next, an embodiment in which the separation method and the recovery method according to the present embodiment are implemented in a single-stage continuous process using a pair of mixing devices (mixing step) and separation device (separation step) will be described. In the separation method according to this embodiment, the mixing step, the separation step, the recovery step, and the like can be performed by batch processing. However, these steps are performed in parallel from the viewpoint of separation / recovery speed and productivity. It is preferable to carry out in a continuous process.

[4.1. Configuration and separation method of particle separator]
First, with reference to FIG. 6, the structure of the particle separation apparatus 8 which concerns on this embodiment, and the separation method and collection | recovery method of the hydrophilic particle 5 and the hydrophobic particle 6 using the said particle separation apparatus 8 are demonstrated. FIG. 6 is a schematic diagram showing the particle separator 8 according to the present embodiment and a single-stage continuous process using the same.

  As shown in FIG. 6, the particle separation device 8 includes a mixer 10 (mixing device), a settler 20 (separation device), a first recovery device 30, and a second recovery device 40.

(1) Mixing step by mixing device (S1)
In the mixing step, a mixture in which the hydrophilic particles 5 and the hydrophobic particles 6 are mixed is mixed with water and a hydrophobic liquid (which will be described below as an example of a hydrophobic organic solvent), and the mixed solution is stirred to form a slurry. To produce a first slurry (S1). Thereby, as shown in FIG. 1, the hydrophilic particles 5 adhere to the surface of the water droplet 4 or are taken into the water droplet 4, and the hydrophobic particles 6 adhere to the surface of the solvent droplet 3, or the solvent liquid. It is taken into the inside of the droplet 3.

  As a mixing apparatus for executing the mixing step (S1), for example, a container equipped with a stirring blade for stirring the mixed solution, a line mixer, or a pump capable of stirring the mixed solution inside can be used. The mixer 10 in the example of FIG. 6 is an example of a container provided with a stirring blade that stirs a mixed solution.

  The mixer 10 is a stirrer having a motor 11 and a stirring blade 12. The mixer 10 is connected to a subsequent setter 20 via a pipe 13. In the container of the mixer 10, a mixture to be separated, water, and a hydrophobic organic solvent having a specific gravity greater than that of water are charged. The mixer 10 rotates the stirring blade 12 by the motor 11 to mix the mixture, water, and the hydrophobic organic solvent, and the first slurry (hydrophilic particles 5, hydrophobic particles 6, water and hydrophobic organic solvent). Solvent mixture) (mixing step).

(2) Separation process by separation device (S2)
The settler 20 is an example of a separation device that performs a separation step. The settler 20 uses the specific gravity difference between water and the hydrophobic organic solvent by allowing the first slurry generated in the mixing step (S1) to stand, and the aqueous phase 1 mainly containing the hydrophilic particles 5; Separation into a hydrophobic organic solvent phase 2 mainly containing hydrophobic particles 6 (S2).

  The settler 20 is an example of a specific gravity separation device that leaves a mixed liquid of a plurality of types of liquid and separates the liquid using a specific gravity difference, and is connected to the mixer 10 via a pipe 13. Further, the settler 20 is connected to the first recovery device 30 at the subsequent stage via a pipe 21, and a pump for sending the aqueous phase 1 (second slurry) containing the hydrophilic particles 5 to the pipe 21. 22 is provided. Further, the settler 20 is also connected to the second recovery device 40 at the subsequent stage via a pipe 23, and the solvent phase 2 (third slurry) containing the hydrophobic particles 6 is sent to the pipe 23. A pump 24 is provided.

  The settler 20 is hydrophilic while separating the first slurry introduced from the mixer 10 through the pipe 13 into an upper phase aqueous phase 1 and a lower phase hydrophobic organic solvent phase 2 by utilizing a specific gravity difference. The hydrophilic particles 5 and the hydrophobic particles 6 are separated by moving the particles 5 to the aqueous phase 1 and moving the hydrophobic particles 6 to the solvent phase 2. This separation principle is as described with reference to FIGS. Thereafter, the aqueous phase 1 (second slurry) containing the hydrophilic particles 5 is discharged from the upper part of the settler 20 to the first recovery device 30 through the pipe 21. On the other hand, the solvent phase 2 (third slurry) containing the hydrophobic particles 6 is discharged from the lower part of the settler 20 to the second recovery device 40 through the pipe 23.

(3) First collection step (S3) by the first collection device 30
The 1st collection | recovery apparatus 30 isolate | separates water from the water phase 1 (2nd slurry) containing the hydrophilic particle 5 isolate | separated by the said separation process (S2), and collect | recovers hydrophilic particles 5 (for example, metal oxide). (S3). The first recovery device 30 includes a centrifuge 31, a drying device 32, and a condenser 33.

  The centrifuge 31 is an example of a solid-liquid separator, and separates the solid suspended from the liquid and the liquid using centrifugal force. The centrifuge 31 is connected to the subsequent drying device 32 via a pipe 34 and is connected to the previous mixer 10 via a pipe 35. The aqueous phase 1 (second slurry) containing the hydrophilic particles 5 is introduced from the settler 20 into the centrifuge 31. The centrifugal separator 31 separates the second slurry into hydrophilic particles 5 and water using a centrifugal force (solid-liquid separation step). The hydrophilic particles 5 dehydrated by the centrifuge 31 are discharged to the drying device 32 through the pipe 34. On the other hand, the water separated by the centrifugal separator 31 is returned to the mixer 10 through the pipe 35 and reused in the mixing step (S1).

  In the present embodiment, the second slurry is solid-liquid separated into water and the hydrophilic particles 5 by centrifugal separation with the centrifuge 31, but instead of this, a solid-liquid separation method such as a filter press or distillation or filtration is used. May be used. However, when the hydrophobic organic solvent has volatility, it is not preferable to use a filter press because the volatilization of the volatilized solvent gas is severe. In order to reduce the leakage of the solvent gas, it is preferable to use, for example, a distillation device, a centrifugal separator, or a filtration device as the solid-liquid separator.

  The drying device 32 dries the hydrophilic particles 5 by heating the hydrophilic particles 5 introduced from the centrifuge 31 and evaporating the remaining water (drying step). The dried hydrophilic particles 5 are discharged from the pipe 36 and collected. The condenser 33 condenses the water vapor sent from the drying device 32 through the pipe 37 and returns it to liquid water (condensing step). The liquid water generated by the condenser 33 is returned to the mixer 10 through the pipe 38 and reused in the mixing step (S1) (first recycling step).

  As described above, in the method for recovering hydrophilic particles 5 according to the present embodiment, in the first recovery step (S3), the aqueous phase 1 (second phase) containing the hydrophilic particles 5 separated in the separation step (S2). The slurry) is separated into hydrophilic particles 5 and water by the centrifuge 31, and then the hydrophilic particles 5 are dried by the drying device 32 to recover the dry powdery hydrophilic particles 5. However, the first recovery step (S3) is not limited to this example, and the solid-liquid separation is performed on the aqueous phase 1 (second slurry) containing the hydrophilic particles 5 separated in the separation step (S2). The hydrophilic particles 5 in the water slurry state may be recovered without performing the step or the drying step. Whether the hydrophilic particles 5 are recovered in a dry powder state or a water slurry state can be appropriately selected according to the recycling application of the hydrophilic particles 5 or the like.

  In the first recovery step (S3), the aqueous phase 1 (second slurry) containing the hydrophilic particles 5 separated in the separation step (S2) is heated to a temperature equal to or higher than the boiling point of the hydrophobic organic solvent. It is preferable to evaporate and remove the hydrophobic organic solvent remaining in the aqueous phase 1 by heating or reducing the pressure to a pressure at which the hydrophobic organic solvent evaporates. Thereby, it can prevent that the hydrophobic organic solvent is contained in the hydrophilic particle | grains 5 collect | recovered, and the quality of the hydrophilic particle | grains 5 can be improved. In the particle separation apparatus 8 according to the present embodiment, the hydrophobic organic solvent remaining in the second slurry is heated and evaporated together with water in the drying process by the drying apparatus 32 shown in FIG. Solvent can be removed. When the hydrophobic organic solvent is volatile, it evaporates at room temperature, but since the specific gravity of the hydrophobic organic solvent is greater than the specific gravity of water, it is often not in direct contact with the gas phase. It is desirable to take measures to prevent the volatilized solvent from scattering.

(4) Second recovery step (S4) by the second recovery device 40
The second recovery device 40 separates the hydrophobic organic solvent from the hydrophobic organic solvent phase 2 (third slurry) containing the hydrophobic particles 6 separated in the separation step (S2), and the hydrophobic particles 6 (for example, Carbon) is collected (S4). The second recovery device 40 includes a centrifuge 41, a drying device 42, and a condenser 43.

  The centrifuge 41 is connected to the subsequent drying device 42 via a pipe 44 and is connected to the previous mixer 10 via a pipe 45. The hydrophobic organic solvent phase 2 (third slurry) containing the hydrophobic particles 6 is introduced from the settler 20 into the centrifuge 41. The centrifuge 41 uses the centrifugal force to separate the third slurry into the hydrophobic particles 6 and the hydrophobic organic solvent (solid-liquid separation step). The hydrophobic particles 6 from which the hydrophobic organic solvent has been separated by the centrifuge 41 are discharged to the drying device 42 through the pipe 44. On the other hand, the hydrophobic organic solvent separated by the centrifugal separator 41 is returned to the mixer 10 through the pipe 45 and reused in the mixing step (S1). In the present embodiment, the third slurry is solid-liquid separated into the hydrophobic organic solvent and the hydrophilic particles 5 by centrifugal separation with the centrifugal separator 41. Instead of this, a solid such as a filter press or distillation or filtration is used. A liquid separation method may be used.

  The drying device 42 heats the hydrophobic particles 6 introduced from the centrifuge 41 and evaporates the remaining hydrophobic organic solvent, thereby drying the hydrophobic particles 6 (drying step). The dried hydrophobic particles 6 are discharged from the pipe 46 and collected. The condenser 43 condenses the hydrophobic organic solvent vapor sent from the drying device 42 through the pipe 47 and returns it to the liquid hydrophobic organic solvent (condensing step). The liquid hydrophobic organic solvent generated in the condenser 43 is returned to the mixer 10 through the pipe 48 and reused in the mixing step (S1) (second recycling step).

  Thus, in the method for recovering hydrophobic particles 6 according to the present embodiment, in the second recovery step (S4), the solvent phase 2 containing the hydrophobic particles 6 separated in the separation step (S2) (third) Slurry) is separated into hydrophobic particles 6 and a hydrophobic organic solvent by a centrifugal separator 41, and then the hydrophobic particles 6 are dried by a drying device 42 to collect dry hydrophobic particles 6 (for example, carbon powder). .

  Heretofore, the steps (S1 to S4) of the separation method according to the present embodiment and the recovery method of the hydrophilic particles 5 or the hydrophobic particles 6 have been described. In this embodiment, since the method is performed in a single-stage continuous process, the mixing step (S1), the separation step (S2), the first recovery step (S3), and the second recovery step (S4) are performed in parallel. . Thereby, the separation efficiency and productivity of the hydrophilic particles 5 and the hydrophobic particles 6 can be improved.

  Further, the water separated from the hydrophilic particles 5 in the first recovery step (S3) is recovered and reused as water charged in the mixing step (S1), and in the second recovery step (S4). The hydrophobic organic solvent separated from the hydrophobic particles 6 is recovered and reused as the hydrophobic organic solvent charged in the mixing step (S1). Thereby, since it is not necessary to make water and a hydrophobic organic solvent disposable, the raw material cost and disposal cost of a hydrophobic organic solvent can be reduced. Further, a large amount of the hydrophobic organic solvent can be repeatedly used in the mixing step (S1) and the separation step (S2), and the chance of the hydrophobic particles 6 coming into contact with the hydrophobic organic solvent can be increased. In the separation step (S2), the hydrophobic particles 6 of the mixture are taken into the hydrophobic particles 6 and the hydrophilic particles 5 are taken into the aqueous phase 1 so that the hydrophilic particles 5 and the hydrophobic particles 6 are highly efficient. Can be separated.

  Therefore, the separation method according to this embodiment can greatly improve the separation speed and separation efficiency of the hydrophilic particles 5 and the hydrophobic particles 6 as compared with the conventional flotation method described in Patent Document 1. For example, by the separation step (S2) according to the present embodiment, the hydrophilic particles 5 and the hydrophobic particles 6 can be quickly separated in a short time of about 1 second to 30 seconds, for example. Further, when the mixture to be separated is, for example, fly ash, the content of the hydrophobic particles 6 contained in the separated and recovered hydrophilic particles 5 can be reduced to 3% by mass or less, and the hydrophilic particles 5 having high purity. Can be recovered. Similarly, when the mixture to be separated is fly ash, for example, the content of the hydrophilic particles 5 contained in the separated and collected hydrophobic particles 6 can be reduced to 50% by mass or less, preferably 20% by mass or less. The hydrophobic particles 6 with high purity can also be recovered.

[4.2. Specific example of separation apparatus]
Next, with reference to FIG. 7 to FIG. 9, a specific example of a separation device (for example, the above-described settler 20) provided in the particle separation device 8 according to the present embodiment will be described.

  As a separation apparatus (settler 20) for performing the separation step (S2) of the separation method according to the present embodiment, for example, the specific gravity of the cross flow separation apparatus 200 shown in FIG. 8 or the upflow separation apparatus 210 shown in FIG. A separation device may be used. Alternatively, a liquid cyclone type separation device (not shown) can be used as the separation device.

  As shown in FIG. 8, in the lateral flow type separation apparatus 200, the mixed liquid is supplied in the horizontal direction from the side surface of the horizontally long container 201, and the mixed liquid is allowed to stand in the container 201. Specific gravity separation is performed in the solvent phase 2. Further, as shown in FIG. 9, in the upward flow type separation device 210, the liquid mixture is supplied upward from the bottom surface of the vertically long container 211, and the liquid mixture is allowed to stand in the container 211. And specific gravity separation into solvent phase 2.

In the case where the mixed liquid is subjected to specific gravity separation using the lateral flow type separation device 200 and the upward flow type separation device 210, the interface between the aqueous phase 1 and the solvent phase 2 has the content of the hydrophilic particles 5 in the aqueous phase 1. since less affected, it is possible to increase the slurry concentration C _S in the aqueous phase 1. In particular, as shown in FIG. 7 and FIG. 9, the upward flow type separation device 210 is a system in which the mixed liquid (first slurry) is supplied upward from the bottom surface of the container 211. sex particles 5 are hardly concentrated, elevated slurry concentration C _S is small. Accordingly, the concentration of the first slurry (that is, the content of the hydrophilic particles 5) supplied to the upward flow separation device 210 can be increased, so that the amount of separation treatment of the hydrophilic particles 5 can be increased and the productivity can be increased. It can be improved.

On the other hand, in the liquid cyclonic separating apparatus, the higher the slurry concentration C _S in the aqueous phase 1, in the vicinity of the interface between the aqueous phase 1 and a solvent phase 2, since the slurry concentration C _S in the aqueous phase 1 is likely to be high, cross flow separation system 200, as compared to the upflow separator 210, it is necessary to lower the slurry concentration C _S in the aqueous phase 1. However, in the liquid cyclone type separation device, centrifugal force is applied along with the rotating flow in the cyclone, so that it is possible to separate the hydrophilic particles 5 having a large particle diameter in the aqueous phase 1.

[4.3. Preferred range of specific gravity of hydrophobic organic solvent]
Next, a preferable range of the specific gravity (liquid specific gravity) of the hydrophobic organic solvent used in the separation method according to the present embodiment will be described in detail.

  The specific gravity of the hydrophobic organic solvent is preferably more than 1.05. When the specific gravity of the hydrophobic organic solvent is 1.05 or less, the specific gravity of the hydrophobic organic solvent and water is close to each other, so that the specific gravity separation rate by the separation device such as the settler 20 is reduced in the separation step (S2). For this reason, since it takes a long time of, for example, 1 minute or more from the time when the liquid mixture (first slurry) is allowed to stand in the separation apparatus to separate into the upper and lower phases of the aqueous phase 1 and the solvent phase 2, the desired Therefore, it is necessary to increase the size of the separation device in order to obtain a large throughput.

Furthermore, when the specific gravity of the hydrophobic organic solvent is 1.05 or less, as shown in FIG. 4, in order to suitably perform phase separation of the aqueous phase 1 and the solvent phase 2, the slurry concentration in the aqueous phase 1 the C _S less than 6 wt%, should be less than 3 wt% some margin, again, separation apparatus is enlarged.

Therefore, by setting the specific gravity of the hydrophobic organic solvent to more than 1.05, after leaving the water and the hydrophobic organic solvent in the separation apparatus, the aqueous phase 1 and the solvent phase can be rapidly obtained in about 1 to 30 seconds, for example. 2 phases can be separated, and the specific gravity separation speed can be improved. Furthermore, since the slurry concentration C _S in the water phase 1 for example at least 3 mass% or more, to enhance the separation process amount per unit time, it is not necessary to use a large separation apparatus.

  Further, the specific gravity of the hydrophobic organic solvent is preferably smaller than the specific gravity of the hydrophobic particles 6 (for example, 1.2 to 1.8), for example, preferably less than 1.8. Thereby, in the said 2nd collection process (S4), the hydrophobic particle 6 can be efficiently isolate | separated from the solvent phase 2 (3rd slurry) containing the hydrophobic particle 6 using the centrifuge 41, and liquid removal Improves. The reason for this will be described below.

  In the separation step (S2), when the aqueous phase 1 and the hydrophobic organic solvent phase 2 are separated in the settler 20, as shown in FIGS. 3A and 3B, due to the difference in specific gravity between the hydrophobic organic solvent and the hydrophobic particles 6, The hydrophobic particles 6 settle or float in the solvent phase 2. Thereafter, in the second recovery step (S4), the hydrophobic particles 6 are separated from the hydrophobic organic solvent phase 2 by solid-liquid separation processing using the centrifuge 41 or the like.

  Since the centrifugal separator 41 performs solid-liquid separation using the specific gravity difference of the object, if “the specific gravity of the hydrophobic particles 6 <the specific gravity of the hydrophobic organic solvent”, the relatively light hydrophobic particles 6 are: Ascend in the centrifuge 41. Then, the hydrophobic particles 6 are concentrated on the surface layer of the hydrophobic organic solvent. However, since the surface layer of the hydrophobic organic solvent fluctuates, the gap between the hydrophobic particles 6 is often not sufficiently small, which is favorable. It becomes difficult to obtain liquid drainage. Therefore, when the centrifuge 41 is used for the solid-liquid separation device in the separation step (S2), the hydrophobic organic solvent is set so that “the specific gravity of the hydrophobic particles 6> the specific gravity of the hydrophobic organic solvent”. Is preferably selected. Even when “the specific gravity of the hydrophobic particles 6 <the specific gravity of the hydrophobic organic solvent”, the centrifuge can be used although the liquid removal property is inferior, or the solid-liquid separation device of the filtration method or the distillation method is adopted. You can also.

  On the other hand, when “the specific gravity of the hydrophobic particles 6> the specific gravity of the hydrophobic organic solvent”, the relatively heavy hydrophobic particles 6 settle in the centrifuge 41 and deposit on the bottom of the centrifuge container. Accordingly, when the hydrophobic particles 6 are recovered, the recovery amount of the extra hydrophobic organic solvent can be reduced, so that the liquid removal property is improved. Therefore, it is preferable to use a hydrophobic organic solvent having a specific gravity smaller than the specific gravity of the hydrophobic particles 6 (for example, 1.2 to 1.8).

[4.4. Preferred range of boiling point of hydrophobic organic solvent]
Next, the preferable range of the boiling point of the hydrophobic organic solvent used in the separation method according to this embodiment will be described.

  In the first recovery step (S3), when the hydrophilic particles 5 are recovered from the aqueous phase 1 containing the hydrophilic particles 5, the hydrophobic organic solvent remaining in the aqueous phase 1 is heated and evaporated. Therefore, it is desirable to remove the hydrophobic organic solvent. Here, the appropriate range of the boiling point of the hydrophobic organic solvent varies depending on whether the recovered hydrophilic particles 5 are cake-like or slurry-like.

  The aqueous phase 1 (second slurry) containing the hydrophilic particles 5 separated by a separation device such as the settler 20 is in the form of a slurry, but when the aqueous phase 1 is dehydrated by the centrifuge 31 or the like, Cake-like hydrophilic particles 5 are obtained. Compared with the 2nd slurry containing the hydrophilic particle 5, the water | moisture content of the cake-like hydrophilic particle 5 is little.

  For this reason, when the hydrophobic organic solvent is removed by heating the cake-like hydrophilic particles 5, less heat is required to evaporate the water, so the hydrophobic organic solvent is heated to evaporate and remove. The amount of heat required for this can be reduced. Therefore, even if a hydrophobic organic solvent having a boiling point exceeding 100 ° C. under atmospheric pressure is used, the cake-like hydrophilic particles 5 can be easily heated to the boiling point or more with a relatively small amount of heat, and the hydrophobic The organic solvent can be removed by evaporation. However, if the boiling point of the hydrophobic organic solvent is higher than 150 ° C., the equipment cost of the heating device and the heat treatment cost increase, so the boiling point of the hydrophobic organic solvent is preferably 150 ° C. or less.

  On the other hand, when removing the hydrophobic organic solvent by heating the slurry-like hydrophilic particles 5, since there is a lot of water, the use of the hydrophobic organic solvent having a boiling point of 100 ° C. or higher not only causes the hydrophobic organic solvent. A large amount of moisture needs to be evaporated, and the amount of heat required for the heat treatment increases. Therefore, it is preferable to use a hydrophobic organic solvent having a boiling point lower than 95 ° C. lower than that of water. Thus, when the slurry-like hydrophilic particles 5 are heated to remove the hydrophobic organic solvent, the heating temperature is set to a temperature lower than 100 ° C. and higher than the boiling point of the hydrophobic organic solvent, thereby suppressing water evaporation. However, the hydrophobic organic solvent can be evaporated. Therefore, the amount of heat required for the heat treatment can be reduced, and the equipment cost and heat treatment cost of the heating device can be suppressed.

  Moreover, when the boiling point of the hydrophobic organic solvent is less than 40 ° C., the amount of solvent volatilized remarkably increases at room temperature and atmospheric pressure, and the amount of solvent that cannot be recovered increases. For this reason, the boiling point of the hydrophobic organic solvent is preferably 40 ° C. or higher so that the hydrophobic organic solvent can be easily handled at room temperature and atmospheric pressure.

  As described above, the boiling point of the hydrophobic organic solvent is preferably 40 ° C. or higher and 150 ° C. or lower under atmospheric pressure. Thereby, the hydrophobic organic solvent can be easily evaporated and removed from the cake-like hydrophilic particles 5 after the solid-liquid separation. Furthermore, the boiling point of the hydrophobic organic solvent is more preferably 40 ° C. or higher and 95 ° C. or lower under atmospheric pressure. Thereby, when the hydrophobic organic solvent is evaporated and removed from the slurry-like hydrophilic particles 5, the evaporation of water can be suppressed, so that the hydrophobic organic solvent is easily evaporated and removed with a small amount of heat. be able to.

[5. Counterflow type multistage continuous process]
Next, a separation method and a recovery method according to the second embodiment of the present invention will be described. The separation method according to the second embodiment employs a countercurrent multistage continuous process in which a plurality of sets of mixing devices and separation devices are installed and the mixing step (S1) and the separation step (S2) are repeated.

As described above, in the separation step (S2) by the separation device (settler 20), after the liquid mixture (first slurry) is allowed to stand, the aqueous phase 1 and the hydrophobic organic solvent phase 2 are converted into the aqueous phase 1 and the hydrophobic organic solvent phase 2 in 1 to 30 seconds, for example. It is preferable to separate. When standing period is too long, the bottom of the slurry concentration C _S of the aqueous phase 1 in the vicinity of the interface between the aqueous phase 1 and a solvent phase 2 is excessively increased, the interface becomes unclear, the separation efficiency of the hydrophobic particles 6 May be reduced. Therefore, the separation method according to the present embodiment is preferably performed in a continuous process, although a batch process is possible.

  Thus, in the separation method according to the present embodiment, the separation speed in the separation step (S2) is fast, and phase separation can be performed in several seconds to several tens of seconds. In this case, as in the second embodiment shown below, the mixing step (S1) using the mixing device (such as the mixer 10) and the separation step (S2) using the separating device (such as the settler 20) are repeatedly applied. A multi-stage continuous process can be employed. From the viewpoint of separation efficiency and quality of the hydrophilic particles 5 and the hydrophobic particles 6, the multi-stage continuous process according to the second embodiment is more than the single-stage continuous process according to the first embodiment (see FIG. 6). Is preferably adopted. As a result, the content of the hydrophobic particles 6 contained in the solid matter recovered from the aqueous phase 1 can be reduced, and the hydrophobic particles 6 contained in the solid matter recovered from the solvent phase 2 can be reduced. The content can be increased.

[5.1. Configuration of particle separator and countercurrent type two-stage continuous process]
Here, with reference to FIG. 10, the configuration of the particle separation apparatus 8A according to the second embodiment and a countercurrent two-stage continuous process using the same will be described. FIG. 10 shows an example of a countercurrent type two-stage continuous process in which the combination of the mixing step (S1) and the separation step (S2) is performed in two stages in the countercurrent type multistage continuous process.

  As shown in FIG. 10, the particle separation device 8A that performs the countercurrent two-stage continuous process according to the second embodiment includes two sets of mixing devices and separation devices (two sets of mixers 10A and 10B and a settler 20A, 20B), a first recovery device 30 and a second recovery device 40. Here, the functions and configurations of the mixers 10A and 10B, the settlers 20A and 20B, the first recovery device 30, and the second recovery device 40 are substantially the same as those of the first embodiment (see FIG. 6 and the like). Since they are the same, detailed description is omitted.

  As shown in FIG. 10, in the particle separation apparatus 8A according to the second embodiment, the first-stage mixer 10A and the settler 20A include the first-stage mixing process (S1_1) and the first-stage separation process (S2_1). Execute. Furthermore, the second-stage mixer 10B and the settler 20B execute the second-stage mixing process (S1_2) and the second-stage separation process (S2_2). And the 1st collection | recovery apparatus 30 collect | recovers the hydrophilic particle | grains 5 and water from the water phase 1 containing the hydrophilic particle | grains 5 isolate | separated by the 2nd separation | separation process (S2_2) (S3). On the other hand, the second recovery device 40 recovers the hydrophobic particles 6 and the hydrophobic organic solvent from the hydrophobic organic solvent phase 2 including the hydrophobic particles 6 separated in the first separation step (S2_1) (S4). ).

  Specifically, first, the solvent phase 2 containing the mixture supplied from the outside, the water recycled in the system, and the hydrophobic particles 6 discharged from the second-stage settler 20B is supplied to the first-stage mixer 10A. It is charged, mixed and stirred (S1_1), and separated into an aqueous phase 1 and a solvent phase 2 (S2_1) by the first-stage settler 20A. Next, the aqueous phase 1 (second slurry) containing the hydrophilic particles 5 discharged from the upper part of the first-stage settler 20A and the remaining hydrophobic particles 6 is introduced into the second-stage mixer 10B through the pipe 21A. Then, it is mixed and stirred with the hydrophobic organic solvent solid-liquid separated by the subsequent centrifugal separator 41 (S1_1), and further separated into the aqueous phase 1 and the solvent phase 2 by the second-stage settler 20B (S2_2). ). Next, the aqueous phase 1 (second slurry) containing the hydrophilic particles 5 discharged from the upper part of the second-stage settler 20B is introduced into the centrifuge 31 of the first recovery device 30 through the pipe 21B, and the solid-liquid The hydrophilic particles 5 are recovered through separation, drying, and the like (S3). The water recovered in the first recovery step (S3) is recycled and input to the first-stage mixer 10A and used for the first-stage mixing step (S1_1).

  On the other hand, the hydrophobic organic solvent is charged into the second-stage mixer 10B and mixed and stirred together with the aqueous phase 1 (second slurry) containing the hydrophilic particles 5 discharged from the upper part of the first-stage settler 20A. (S1_2) Further, the water phase 1 and the solvent phase 2 are separated (S2_2) by the second-stage settler 20B. Next, the solvent phase 2 (third slurry) containing the hydrophobic particles 6 discharged from the lower part of the second-stage settling 20B and the remaining hydrophilic particles 5 is supplied to the first-stage mixer 10A through the pipe 23B. The mixture and the water solid-liquid separated by the subsequent centrifugal separator 31 are mixed and stirred (S1_1), and separated into the aqueous phase 1 and the solvent phase 2 by the first-stage settler 20A (S2_1). . Next, the solvent phase 2 (third slurry) containing the hydrophobic particles 6 discharged from the lower portion of the first-stage settling 20A is introduced into the centrifuge 41 of the second recovery device 40 through the pipe 23A, and the solid-liquid Through separation, drying, etc., the hydrophobic particles 6 are recovered (S4). The hydrophobic organic solvent recovered in the second recovery step (S4) is recycled, charged into the second-stage mixer 10B, and used for the second-stage mixing step (S1_2).

  As described above, in the countercurrent two-stage continuous process according to the second embodiment, the combination of the mixing step (S1) and the separation step (S2) is performed in two stages using two sets of mixing devices and separation devices. Is done. Thereby, since the aqueous phase 1 containing the hydrophilic particles 5 and the solvent phase 2 containing the hydrophobic particles 6 are separated in two stages, the hydrophilic particles are compared with the single-stage continuous process according to the first embodiment. 5 and the separation efficiency of the hydrophobic particles 6 can be further improved. Therefore, the hydrophilic particles 5 having a lower content of the hydrophobic particles 6 and the hydrophobic particles 6 having a lower content of the hydrophilic particles 5 can be recovered. Furthermore, since it is a counter-current type continuous process, the separation rate and productivity are not reduced as compared with the single-stage continuous process according to the first embodiment.

[5.2. Separation method using countercurrent multistage continuous process]
In FIG. 10, the countercurrent type two-stage continuous process has been described. However, the separation method according to the second embodiment can be applied to a countercurrent type multistage continuous process having N stages or more (N is an integer of 3 or more). It is.

  FIG. 11 is a process diagram showing a separation method by an N-stage countercurrent multistage continuous process. As shown in FIG. 11, in the N-stage countercurrent multi-stage continuous process, the combination of the mixing process (S1) and the separation process (S2) is repeated N stages. As the N content increases, the separation efficiency of the hydrophilic particles 5 and the hydrophobic particles 6 is improved, and the contents of the hydrophilic particles 5 and the hydrophobic particles 6 in the collected solid can be increased.

  In the example shown in FIG. 11, for example, in the first stage mixing step (S1_1), the mixture to be separated and water are introduced, and in the second to Nth stage mixing steps (S1_2 to N), water is used alone. It is not thrown in. On the other hand, in the mixing step (S1_N) of the Nth stage, which is the final stage, the hydrophobic organic solvent is introduced, and in the mixing process (S1_1 to N-1) of the 1st to N-1th stages, the hydrophobic organic solvent is used. Is not input alone.

  Then, the aqueous phase 1 including the hydrophilic particles 5 and the remaining hydrophobic particles 6 separated in the separation step (S2_n) of the nth stage (n is an integer of 1 or more and N-2 or less), and the n + 2th stage The solvent phase 2 including the hydrophobic particles 6 separated in the separation step (S2_n + 2) and the remaining hydrophilic particles 5 is mixed and slurried in the n + 1 stage mixing step (S1_n + 1). Next, in the n + 1-stage separation step (S2_n + 1), the aqueous phase 1 mainly containing the hydrophilic particles 5 and the solvent phase 2 mainly containing the hydrophobic particles 6 are separated.

  While the combination of the mixing step (S1) and the separation step (S2) is repeated at each stage, the water phase 1 having a higher content of hydrophilic particles 5 is obtained from the first stage to the N stage. The solvent phase 2 having a higher content of the hydrophobic particles 6 is obtained from the Nth stage toward the first stage. Thereafter, in the first recovery step (S3) in the latter stage of the Nth stage, the hydrophilic particles 5 and the water are separated and recovered from the aqueous phase 1 having a high content of the hydrophilic particles 5, respectively. It is returned to the first stage mixing step (S1_1) and reused. On the other hand, in the second recovery step (S4) in the latter stage of the first stage, the hydrophobic particles 6 and the hydrophobic organic solvent were respectively separated and recovered from the solvent phase 2 having a high content of the hydrophobic particles 6, and recovered. The hydrophobic organic solvent is returned to the N-th mixing step (S1_N) and reused.

  In this way, by performing the countercurrent multistage continuous process in N stages, the separation efficiency of the hydrophilic particles 5 and the hydrophobic particles 6 can be further improved as compared with the single-stage continuous process according to the first embodiment. In addition, the hydrophilic particles 5 having a low content of the hydrophobic particles 6 and the hydrophobic particles 6 having a low content of the hydrophilic particles 5 can be recovered, and the separation rate and productivity are not lowered. .

  In addition, in the example of FIG. 11, although the mixture which is a separation object is thrown in by the mixing process (S1_1) of the 1st stage, the said mixture is thrown in by the mixing process (S1_2-N) of another stage. Also good.

[5.3. Countercurrent multi-stage continuous process with additional cleaning process]
Next, with reference to FIG.12 and FIG.13, the countercurrent type multistage continuous process which added the washing | cleaning process by water is demonstrated.

  FIG. 12 shows a separation method by an N-stage countercurrent multi-stage continuous process in which one-stage washing steps (S5, S6) are added to the N-stage countercurrent multistage continuous process shown in FIG. It is process drawing. As shown in FIG. 12, one-stage cleaning steps (S5, S6) are added before the first-stage mixing step (S1_1) and separation step (S2_1).

  In the washing steps (S5, S6), the trace amount of hydrophilic particles 5 is removed from the solvent phase 2 including the hydrophobic particles 6 separated in the first-stage separation step (S2_1) and the remaining trace amount of hydrophilic particles 5. It is a process for removing. This cleaning step (S5, S6) includes a cleaning mixing step (S5) and a cleaning separation step (S6).

  In the cleaning mixing step (S5), the hydrophobic particles 6 separated in the first separation step (S2_1) and the remaining trace amount of hydrophilic particles using the above-described mixing apparatus (for example, the mixer 10 in FIG. 6). Water is added to the solvent phase 2 (third slurry) containing 5 and mixed and stirred to form a slurry. Next, in the separation step for washing (S6), the slurry generated in the mixing step for washing (S5) is converted into the aqueous phase 1 and the solvent phase 2 using the separation device described above (for example, the settler 20 in FIG. 6). While separating, the hydrophilic particles 5 are separated from the hydrophobic particles 6 by moving a small amount of the hydrophilic particles 5 to the aqueous phase 1.

  Thereafter, the solvent phase 2 containing the hydrophobic particles 6 separated in the separation step for washing (S6) is sent to the second recovery step (S4), and the hydrophobic phase 6 from the solvent phase 2 containing the hydrophobic particles 6 is sent. And the hydrophobic organic solvent are separated and recovered, and the recovered hydrophobic organic solvent is returned to the N-th mixing step (S1_N) and reused. On the other hand, the aqueous phase 1 containing a small amount of hydrophilic particles 5 separated in the separation step for washing (S6) is sent to the first mixing step (S1) and mixed with the mixture and the hydrophobic organic solvent, Thereafter, the same processing as described above is performed.

  As described above, in the washing step (S5, S6), by adding only water to the solvent phase 2 containing the hydrophobic particles 6 and a small amount of the hydrophilic particles 5, and washing the hydrophilic particles 5 with the water, The trace amount of hydrophilic particles 5 remaining in the solvent phase 2 can be taken into the water and removed. Thereby, the content rate of the hydrophobic particles 6 in the solid recovered from the solvent phase 2 in the second recovery step (S4) can be further increased.

  Next, a countercurrent multi-stage continuous process in which the cleaning steps (S5, S6) are performed in multiple stages will be described with reference to FIG. FIG. 13 is a process diagram showing a separation method by a countercurrent multistage continuous process in which an M stage cleaning step (S5, S6) is added to the N stage countercurrent multistage continuous process shown in FIG. is there. As shown in FIG. 13, before the first stage mixing step (S1_1) and separation step (S2_1), M stage (M is an integer of 2 or more) washing steps (S5_1-M, S6_1). ~ -M) has been added.

  As shown in FIG. 13, the combination of the cleaning mixing step (S5) and the cleaning separation step (S6) in the cleaning step may be repeated M stages. As the amount of M increases, a small amount of the hydrophilic particles 5 remaining in the solvent phase 2 can be effectively separated and removed, and the inclusion of the hydrophilic particles 5 in the hydrophobic particles 6 recovered in the second recovery step (S4). The rate can be reduced.

  In the example illustrated in FIG. 13, for example, in the −M-th cleaning mixing step (S5_−M), water is added, and the −M + 1 to −1th cleaning mixing step (S5_−M + 1 to −1). ) And the 1st to Nth stage mixing steps (S1_1 to N), water is not added alone. On the other hand, in the mixing step (S1_N) of the Nth stage which is the final stage, the hydrophobic organic solvent is added, the mixing process (S1_1 to N-1) of the 1st to N-1th stages, and −M to − In the first-stage cleaning mixing step (S5_-M to -1), the hydrophobic organic solvent is not added alone.

  And the solvent phase 2 containing the hydrophobic particles 6 and the remaining hydrophilic particles 5 separated in the separation step for washing (S6_-m) in the -m-th stage (m is an integer of 1 or more and M-2 or less) The aqueous phase 1 containing the hydrophilic particles 5 and the remaining hydrophobic particles 6 separated in the separation step (S6_-m-2) for the -m-2 stage cleaning is the -m-1 stage cleaning. Is mixed and slurried in the mixing step (S5_-m-1). Subsequently, in the -m-1 stage separation step (S6_-m-1), the aqueous phase 1 mainly containing the hydrophilic particles 5 and the solvent phase 2 mainly containing the hydrophobic particles 6 are separated. The

  By repeating the combination of the cleaning mixing step (S5) and the cleaning separation step (S6) at each stage, the solvent having a higher content of the hydrophobic particles 6 from the -1 stage to the -M stage. While the phase 2 is obtained, the water phase 1 having a higher content of the hydrophilic particles 5 is obtained from the −M stage to the −1 stage. Thereafter, in the second recovery step (S4) after the -M stage, the hydrophobic particles 6 and the hydrophobic organic solvent are separated and recovered from the solvent phase 2 having a high content of the hydrophobic particles 6, respectively, and recovered. The hydrophobic organic solvent is returned to the N-th mixing step (S1_N) and reused.

  As described above, in the -M to -1 stage, a small amount of the hydrophilic particles 5 remaining in the solvent phase 2 is removed by adding water, and in the 1 to N stages, the aqueous phase 1 is added by adding the solvent. The remaining hydrophobic particles 6 are removed. As described above, in the countercurrent multistage continuous process, by performing the M-stage cleaning steps (S5, S6), compared with the countercurrent multistage continuous process shown in FIG. The hydrophobic particles 6 can be separated to recover the hydrophobic particles 6 having a low content of the hydrophilic particles 5, and the separation speed and productivity are not lowered.

[5.4. Separation of magnetic deposits]
Next, with reference to FIG. 14, a separation method and a recovery method including a magnetic separation process according to a third embodiment of the present invention will be described.

When the mixture to be separated by the above separation method is fly ash, for example, when fly ash is mixed with a mixed solution of water and a hydrophobic organic solvent and left to stand, the metal oxide (hydrophilic particles 5) containing iron is mainly used. It is separated into an aqueous phase 1 containing and a solvent phase 2 containing unburned carbon (hydrophobic particles 6). Since the specific gravity of iron is large (specific gravity: 4 to 5), if the particle size of iron is larger than 6 μm, the iron is a hydrophilic particle but settles into the solvent phase 2 as explained in FIG. There is also. Thus, the fly ash may contain magnetic deposits such as iron as contamination. In a furnace such as a coal-fired power plant, the oxygen concentration is low and the time that the coal stays in the furnace is short, so a part of iron (Fe ₂ O ₃ ) contained in the coal Is reduced to magnetite (Fe ₃ O ₄ ). Thus, the iron is primarily a magnetite powder (Fe 3 _{O 4),} so that the remaining fly ash.

  In the separation method according to the present embodiment, the magnetic deposit such as magnetite powder is preferably separated and recovered from the hydrophilic particles 5 and the hydrophobic particles 6. In view of this, the third embodiment further includes a magnetic separation step of attracting and separating the magnetized material (for example, magnetite powder) mixed in the mixture to be separated (for example, fly ash) using a magnet.

  FIG. 14 is a schematic diagram showing a particle separation device 8B for performing a separation method including a magnetic separation process according to the third embodiment and a countercurrent multistage continuous process using the particle separation device 8B. In addition, the particle separator 8B (refer FIG. 14) which concerns on 3rd Embodiment is compared with the particle | grain separator 8 (refer FIG. 10) which concerns on the said 2nd Embodiment, and a magnetic separation strainer 51, 52, 53. The other features are the same as those of the second embodiment, and the detailed description thereof is omitted.

  As shown in FIG. 14, for example, magnetic separation strainers 51, 52, and 53 are conceivable as magnetic separation devices for executing the magnetic separation process. In the particle separator 8B that executes a countercurrent multistage continuous process, the installation position of the magnetic separation device varies depending on the purpose of magnetic separation, and may be, for example, the following (1) to (3).

(1) When separating magnetic deposits from the entire mixture to be separated, magnetic separation is performed at the position of the pipe 13A connecting the mixer 10A and the settler 20A in the subsequent stage of the first-stage mixing apparatus (mixer 10A) shown in FIG. A strainer 51 may be installed.
(2) When separating magnetic deposits from solids (mainly hydrophobic particles 6) mixed in the hydrophobic organic solvent phase 2, the latter stage of the first stage separation device (settler 20A) shown in FIG. In this case, the magnetic separation strainer 52 may be installed at the position of the pipe 23A that connects the settler 20A and the second recovery device 40.
(3) When separating magnetic deposits from solids (mainly hydrophilic particles 5) mixed in the aqueous phase 1, the settling is performed in the subsequent stage of the second stage separation apparatus (settler 20B) shown in FIG. What is necessary is just to install the magnetic separation strainer 53 in the position of the piping 21B which connects 20B and the 1st collection | recovery apparatus 30. FIG.

  In the case of using magnetic separation strainers 51, 52, 53 as the magnetic separation device, as a method of collecting magnetic deposits, for example, when magnetic deposits are accumulated to some extent in the electromagnetic strainer, the magnetic deposits are manually taken out from the inside of the strainer and collected. There are a method and a method of automatically taking out and collecting the magnetic deposit. These manual recovery or automatic recovery may be selected in accordance with the content of magnetic deposits and the processing amount.

Here, the magnetic separation method when the mixture to be separated is fly ash will be described in detail. As described above, the magnetized material contained in fly ash is mainly magnetite powder (Fe ₃ O ₄ ). The magnetite powder is oxidized to Fe ₂ O ₃ at a high temperature and turns red. On the other hand, metal oxides such as SiO ₂ and Al ₂ O ₃ constituting fly ash are light gray or white. Here, by removing the magnetic deposits from the fly ash by the magnetic separation process according to the present embodiment, the color unevenness of the recovered metal oxide (hydrophilic particles 5) can be reduced, and the quality can be improved. In this case, it is preferable to install the magnetic separation device at the position of (1) magnetic separation strainer 51 and (3) magnetic separation strainer 53 shown in FIG.

  However, when the fine magnetic deposit powder having a size of less than about 6 μm existing in the water phase 1 is difficult to be transferred to the solvent phase 2 due to the interfacial tension acting at the interface between the water phase 1 and the solvent phase 2. There are many. Therefore, in order to remove the fine magnetic deposit powder contained in the aqueous phase 1, it is preferable to install a magnetic separation device at the position of (3) magnetic separation strainer 53 shown in FIG. Further, in order to increase the carbon content in the unburned carbon and increase the efficiency as a fuel, in order to remove the magnetic deposits contained in the solvent phase 2 together with the unburned carbon (hydrophobic particles 6), FIG. It is preferable to install a magnetic separator at the position of (2) magnetic separator strainer 52 shown in FIG.

  As described above, if the magnetic separation process of the magnetic deposit is performed using fly ash as a separation target in the steel industry, since the fine ash powder is included in the fly ash, (3) the magnetic separation strainer 53 shown in FIG. It is considered that it is preferable to install a magnetic separator at the position, collect the magnetic deposit powder containing iron, and use it in the iron making process together with the unburned carbon concentrate.

In addition, although the example which magnetically selects the iron content in fly ash was demonstrated as the magnetic material isolate | separated by a magnetic separation process above, a magnetic material is not limited to this example. For example, blast furnace gas ash contains spinel ferrite having magnetic spinel crystal structure, AFe ₂ O ₄ (A is Fe, Mn, Ni, Zn, etc.) and the like as magnetic deposits. Therefore, when the mixture to be separated is blast furnace gas ash, it is also possible to separate and collect these magnetic deposits from the blast furnace gas ash by magnetic separation.

  Examples of the present invention will be described in detail below, but the present invention is not limited to these examples.

[Example 1]
First, the test of Example 1 will be described with reference to Table 4. Table 4 shows the test conditions and results of Example 1.

As shown in Table 4, after putting 80 ml of water and 20 ml of various hydrophobic liquids into a 100 ml graduated cylinder with a stopper, the slurry concentration C _S [mass%] in the aqueous phase 1 is the concentration described in Table 4. The mixture was charged so that Next, the mixed solution in the graduated cylinder was vigorously mixed by hand for 10 seconds and then allowed to stand for 10 seconds. Thereafter, a sample was immediately taken from one portion of the aqueous phase, the solid matter in the aqueous phase 1 was recovered, and the content of the recovered solid matter was measured. It was also measured content C _B of the hydrophobic particles 6 solids in that the recovered. Moreover, to calculate the hydrophobic particle separation rate K _A represented by the following formula (4). On the other hand, hydrophilic particles recovery K _B was calculated by the following equation (5).

K _A [mass%] = {(m _A −m _B ) / m _A } × 100 (4)
K _B [mass%] = (m _P / m _Q ) × 100 (5)
m _A [g]: Mass of charged hydrophobic particles 6 m _B [g]: Mass of hydrophobic particles 6 contained in aqueous phase 1 m _Q [g]: Mass of charged hydrophilic particles 5 m _P [g ]: Mass of the hydrophilic particles 5 contained in the aqueous phase 1

Moreover, as shown in Table 4, in the fly ash of Comparative Example 1 and Examples 1-1 to 1-9 used as the mixture to be separated, 1.9% by mass of carbon was contained, and its volume The standard 50% particle size was 19 μm. The fly ash of Examples 1-10 to 1-13 contained 5.3% by mass of carbon, and the volume-based 50% particle size was 21 μm. The blast furnace gas ash of Example 1-14 contained 26% by mass of carbon, and the volume-based 50% particle size was 15 μm. The volume-based 50% particle size of the polyethylene terephthalate powder of Example 1-15 was 94 μm. The volume-based 50% particle size of the vinyl chloride resin powder of Example 1-16 was 87 μm. In Examples 1-15 and 1-16, the volume-based 50% particle diameter of Fe ₂ O ₃ powder (reagent) is 1.2 μm, and the hydrophobicity of the mixture used in Examples 1-15 and 1-16 The particle content was 10% by mass and 10.4% by mass, respectively. In Example 1-17, the mixture obtained by slurrying the fly ash used in Examples 1-10 to 1-13 with water was pulverized with beads having a diameter of 0.3 mm for 5 seconds. Fly ash obtained by drying the mixed solution after such pulverization was used. The volume-based 50% particle size was measured by a wet method in which a sample was slurried with water using a laser diffraction / scattering method and dispersed by stirring and ultrasonic waves.

Results of the above test, as shown in Table 4, the hydrophilic particles recovery _{K B} is any even 73 wt% or more embodiments 1-1 to 1-17, in particular that of Example 1-1 1- In Examples other than 6, it was 92 mass% or more. Therefore, it turns out that the hydrophilic particles 5 can be recovered from the mixture at a high recovery rate by the separation method according to the present embodiment. Hydrophobic particle separation rate _{K A} is an example 1-15,1-16, very high and 96 to 98 wt%, in Examples 1-1 to 1-14 was 42 to 56% by weight. Therefore, by the separation method according to the present embodiment, the content of the hydrophobic particles 6 contained in the recovered hydrophilic particles 5 can be greatly reduced, and the high-quality hydrophilic particles 5 having a high content can be recovered. confirmed. Furthermore, in Example 1-17 in which fly ash was pulverized, the hydrophobic particle separation rate K _A and the hydrophilic particle recovery rate K _B were compared with Example 1-11, which was the same conditions except for pulverization. Both rose and the content rate of the hydrophobic particle 6 contained in the collect | recovered hydrophilic particle 5 also reduced significantly.

The content C _B of the hydrophobic particles 6 in the solid recovered from the aqueous phase 1 was 1.2% by mass in Example 1-1 in which the specific gravity of silicone oil, which is a hydrophobic liquid, was 1.07. It was. On the other hand, in Comparative Example 1 the specific gravity of the silicone oil is 1.03, and the content _{C B} was 1.9 wt%. Therefore, it can be seen that the specific gravity separation rate can be improved by setting the specific gravity of the hydrophobic liquid to more than 1.05. That is, in Comparative Example 1, since the specific gravity of the silicone oil is 1.05 or less, the specific gravity of the aqueous phase 1 is close to the specific gravity of the solvent phase 2 which is a hydrophobic liquid phase, and the phase separation rate is very slow. After mixing, the mixture was allowed to stand for 1 minute, but phase separation hardly proceeded. Therefore, about 20 ml of the upper part of the graduated cylinder was collected, the solid was recovered, and the content of the hydrophobic particles 6 in the recovered product was measured and found to be 1.9% by mass. That is, there was almost no change from the content of the hydrophobic particles 6 in the input fly ash.

Incidentally, when comparing the examples 1-2～1-6 with varying slurry concentration C _S in the aqueous phase 1, the slurry concentration in the aqueous phase 1 is equal to or greater than 38 wt%, was recovered from the aqueous phase 1 solids content C _B of the hydrophobic particles 6 in the object is increased, especially if the slurry concentration is 47 mass% in the aqueous phase 1 (example 1-6), although C _B was 1.7 wt% Compared to the content of hydrophobic particles (1.9% by mass) in the original sliash, it is only slightly reduced. This, too high slurry concentration C _S in the aqueous phase 1, the interface between the aqueous phase 1 and a solvent phase 2 is unclear, the content of the hydrophobic particles 6 in the solid recovered from the aqueous phase 1 C _B is presumed to represent that it did not so much lowered.

[Example 2]
Next, the test of Example 2 will be described. In the test of Example 2, the separation process was performed in a single-stage batch process using the particle separator 8 provided with the mixer 10 and the settler 20 shown in FIG. First, water and a bromine-based organic solvent (1-bromopropane) were added at a rate of 1 L / min and fly ash at 75 g / min in a mixer 10 (capacity 0.3 L) as a mixing device, and vigorously mixed with a stirrer. The mixed liquid was continuously fed into a settling machine 20 (diameter: 40 mm, height: 300 mm) as an upflow separator at a flow rate of 2 L / min. A bromine-based organic solvent phase (solvent phase 2) is formed at the lower portion of the settler 20, an aqueous phase 1 is formed at the upper portion, and a thin film of bromine-based organic solvent phase is formed between the aqueous phase 1 and air. It was. And the water phase 1 was continuously extracted from the surface layer part of the water phase 1 from the location about 3 cm below at 1 L / min, and the sample of the water phase 1 was obtained. On the other hand, the bromine-based organic solvent phase was continuously withdrawn at a rate of 1 L / min from a position about 3 cm from the bottom of the bromine-based organic solvent phase to obtain a sample of solvent phase 2. Each sample was drained by centrifugation (1,700 G × 30 seconds) and then dried in a drying furnace to collect solid matter. Based on the above formulas (4) and (5), the hydrophobic particle separation rate K _A and the hydrophilic particle recovery rate K _B were calculated. The fly ash used contained 13% by mass of carbon, and the volume-based 50% particle size was 21 μm. The volume-based 50% particle size was measured in the same manner as in Example 1.

As a result of the test of Example 2, the hydrophobic particle separation rate K _A was 55% by mass, and the hydrophilic particle recovery rate K _B was 90% by mass. The content C _B of the hydrophobic particles 6 solids which had been recovered from the aqueous phase 1 is 6.9 wt%, the hydrophobic particles solids content of which had been recovered from the brominated organic solvent phase, It was 53 mass%. According to the test results, it was confirmed that the hydrophilic particles 5 and the hydrophobic particles 6 can be separated and recovered with high separation efficiency by the separation method using the particle separation device 8 according to the present embodiment.

[Example 3]
Next, the test of Example 3 will be described with reference to FIG. In addition, FIG. 15 shows the change in the content of the hydrophobic particles 6 in the solid of the aqueous phase 1 or the solvent phase 2 in each stage of the countercurrent three-stage continuous process (see FIG. 11) that does not include a washing step. Show.

  In the test of Example 3, a counter-current type three-stage continuous process (mixing-upflow separation, in FIG. 11) was performed using a particle separator 8A in which three sets of the mixer and separator used in Example 2 were connected. N = 3). Also in Example 3, the test was performed under the same conditions as in Example 2 using the fly ash used in Example 2.

Results of the test of Example 3, a hydrophobic particle separation rate K _A is 81 mass%, hydrophilic particles recovery K _B was 91% by mass. Further, as shown in FIG. 15, the content C _B of the hydrophobic particles 6 in the solid recovered from the aqueous phase 1 is 2.9% by mass, and the solids recovered from the bromine-based organic solvent phase The hydrophobic particle content was 56% by mass. According to the test results, in the countercurrent three-stage continuous process of Example 3, both the hydrophobic particle separation rate K _A and the hydrophilic particle recovery rate K _B are compared to Example 2 which is a single-stage batch process. The content C _B of the hydrophobic particles 6 in the solid recovered from the aqueous phase 1 decreases, and the content of the hydrophobic particles 6 in the solid recovered from the bromine-based organic solvent phase increases. confirmed.

[Example 4]
Next, the test of Example 4 will be described with reference to FIG. FIG. 16 shows hydrophobic particles in the solids of the aqueous phase 1 or the solvent phase 2 in each stage of the countercurrent type four-stage continuous process (see FIG. 13) including the washing steps (S5, S6) and the washing step. 6 shows the change in the content ratio.

  In the test of Example 4, a set of the first-stage mixing device and separation device shown in FIG. 12 was added to the particle separation device 8A used in Example 3 above, and the first-stage cleaning step (S5). , S6) was carried out in a countercurrent type four-stage continuous process (mixing-upflow separation, when N = 4 in FIG. 12). Also in Example 4, tests were performed under the same conditions as in Example 3 using the fly ash used in Example 3.

Results of the test of Example 4, the hydrophobic particle separation rate K _A is 82 mass%, hydrophilic particles recovery K _B was 91% by mass. Moreover, as shown in FIG. 16, the content C _B of the hydrophobic particles 6 in the solid recovered from the aqueous phase 1 is 2.8% by mass, and the solids recovered from the bromine-based organic solvent phase The content rate of the hydrophobic particles 6 was 58% by mass. According to the test results, in the countercurrent type four-stage continuous process of Example 4, as compared with Example 3, the washing process (S5, S6), the fourth mixing process (S1-4), and the separation process. (S2-4) by adding, while the content C _B of the hydrophobic particles 6 solids which had been recovered from the aqueous phase 1 in low, hydrophobic particles of solid material which had been recovered from the brominated organic solvent phase It was confirmed that the content of 6 can be remarkably improved.

[Example 5]
Next, the test of Example 5 will be described with reference to FIG. In addition, FIG. 17 shows the change of the content rate of the hydrophobic particle 6 similar to FIG.

  In the test of Example 5, the fly ash used in Example 3 was slurried with water (slurry concentration 500 g / l). Using a bead mill, the slurry was charged at 1 l / min into a container (1 l) containing 1 kg of zirconia beads having a diameter of 500 μm and stirred at 1500 rpm to obtain a slurry after pulverization. After pulverization, the slurry was dried to obtain fly ash after pulverization as a dry powder. After pulverization, the solid was collected in the same manner as in Example 4 using fly ash, and the results shown in FIG. 17 were obtained.

The results of the tests of Example 5, the hydrophobic particle separation rate K _A is 97 mass%, hydrophilic particles recovery K _B was 97% by mass. Moreover, as shown in FIG. 17, the content C _B of the hydrophobic particles 6 in the solid recovered from the aqueous phase 1 is 0.4% by mass, and the solids recovered from the bromine-based organic solvent phase The content of the hydrophobic particles 6 was 84% by mass. According to the test results, fly ash was pulverized in advance to recover from the bromine-based organic solvent phase while further reducing the content C _B of the hydrophobic particles 6 in the solid recovered from the aqueous phase 1. It was confirmed that the content of the hydrophobic particles 6 in the solid can be remarkably improved.

[Example 6]
Next, a test in which a magnetic separation process using a neodymium magnet is performed on the above-described Example 1-3 (see Table 4) will be described.

The iron content in the fly ash used as the separation object was 5.7% by mass in terms of magnetite. When this fly ash was mixed with water alone to form a water slurry, a neodymium magnet was brought close to the magnetized material, and a magnetized material containing 32% by mass in terms of magnetite could be obtained, and 35% by mass in terms of magnetite. % Iron was recovered. Moreover, when the neodymium magnet was brought close to the water phase 1 separated in Example 1-3 and the magnetized material was separated, a magnetized material containing 34% by mass in terms of magnetite can be obtained, and 37% by mass in terms of magnetite. Iron was recovered. Furthermore, when a neodymium magnet was brought close to the solvent phase 2 separated in Example 1-3 and the magnetized material was separated, a magnetized material of 24% by mass in terms of magnetite could be obtained. In either case, the iron concentration in terms of magnetite was increased, and it was confirmed that the magnetic deposits could be recovered by the magnetic separation process. In the above test, the iron content in fly ash was measured by the ICP method and converted to magnetite (Fe ₃ O ₄ ).

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Aqueous phase 2 Hydrophobic solvent phase 3 Solvent droplet 4 Water droplet 5 Hydrophilic particle 6 Hydrophobic particle 7 Concentrating part 8, 8A, 8B Particle separator 10 Mixer (mixing device)
20 Settler (separator)
DESCRIPTION OF SYMBOLS 30 1st collection apparatus 31 Centrifuge 32 Drying apparatus 33 Condenser 40 2nd collection apparatus 41 Centrifuge 42 Drying apparatus 43 Condenser 51, 52, 53 Magnetic separation strainer 200 Cross-flow type separation apparatus 210 Upflow type separation apparatus S1 Mixing process S2 Separation step S3 First recovery step S4 Second recovery step S5 Cleaning mixing step S6 Cleaning separation step

Claims (20)

In a separation method for separating hydrophobic particles and hydrophilic particles from a mixture of hydrophobic particles and hydrophilic particles,
A mixing step in which the mixture is mixed with water and a hydrophobic liquid having a specific gravity greater than that of the water to form a slurry; and
While separating the slurry generated in the mixing step into an aqueous phase and a hydrophobic liquid phase, the hydrophilic particles are moved to the aqueous phase, and the hydrophobic particles are moved to the hydrophobic liquid phase. A separation step of separating the hydrophobic particles and the hydrophilic particles;
Including a separation method.   In the separation step, the slurry is allowed to stand in a separation device, thereby utilizing the difference in specific gravity so that the slurry includes the aqueous phase containing the hydrophilic particles and the hydrophobic liquid containing the hydrophobic particles. The separation method according to claim 1, wherein the separation is carried out into phases.   The separation method according to claim 1 or 2, wherein a combination of the mixing step and the separation step is repeated N steps (N is an integer of 2 or more) by a countercurrent multi-stage continuous process. N is an integer greater than or equal to 3,
In the first stage, the mixture and the water are charged,
The hydrophobic liquid is charged in the mixing step of the Nth stage,
the aqueous phase containing the hydrophilic particles and the remaining hydrophobic particles separated in the separation step in the nth stage (n is an integer of 1 or more and N-2 or less), and the separation process in the (n + 2) th stage. The separation method according to claim 3, wherein the separated hydrophobic particles and the hydrophobic liquid phase including the remaining hydrophilic particles are mixed and slurried in the mixing step of the (n + 1) th stage. A cleaning step of removing the hydrophilic particles remaining in the hydrophobic liquid phase including the hydrophobic particles separated in the separation step of the first stage;
The washing step includes
A washing mixing step of adding the water to the hydrophobic liquid phase containing the hydrophobic particles separated in the separation step in the first stage and the remaining hydrophilic particles, and mixing to make a slurry;
While separating the slurry produced in the mixing step for washing into an aqueous phase and a hydrophobic liquid phase, the remaining hydrophilic particles are moved to the aqueous phase, whereby the hydrophobic particles and the remaining hydrophilic particles are moved. A separation step for washing to separate the functional particles;
The separation method according to claim 3, comprising:   The separation method according to claim 5, wherein a combination of the washing mixing step and the washing separation step in the washing step is repeated in M stages (M is an integer of 2 or more). A first recovery step of separating the water from the aqueous phase containing the hydrophilic particles separated in the separation step, and collecting the hydrophilic particles;
A second recovery step of separating the hydrophobic liquid from the hydrophobic liquid phase containing the hydrophobic particles separated in the separation step, and collecting the hydrophobic particles;
Further including
The separation according to any one of claims 1 to 6, wherein the water separated in the first recovery step and the hydrophobic liquid separated in the second recovery step are reused in the mixing step. Method. In the first recovery step,
The hydrophobic liquid remaining in the aqueous phase is removed by subjecting the aqueous phase containing the hydrophilic particles separated in the separation step to at least one of heating and decompression. The separation method according to claim 7.   The separation method according to any one of claims 1 to 8, further comprising a magnetic separation step of attracting and separating the magnetic material mixed in the mixture by using a magnet. The hydrophobic liquid is a hydrophobic organic solvent,
The separation method according to any one of claims 1 to 9, wherein the specific gravity of the hydrophobic organic solvent is more than 1.05 and smaller than the specific gravity of the hydrophobic particles. The hydrophobic liquid is a hydrophobic organic solvent,
The separation method according to claim 1, wherein the hydrophobic organic solvent has a boiling point of 40 ° C. or higher and 150 ° C. or lower under atmospheric pressure. The hydrophobic liquid is a hydrophobic organic solvent,
The separation method according to claim 1, wherein the hydrophobic organic solvent has a boiling point of 40 ° C. or higher and 95 ° C. or lower under atmospheric pressure. The hydrophilic particles are metal oxides,
The separation method according to any one of claims 1 to 12, wherein the hydrophobic particles are coke powder or coal powder.   The separation method according to any one of claims 4 to 13, wherein the mixture is fly ash.   The separation method according to claim 14, further comprising a pulverization step of performing a pulverization process on the fly ash prior to the separation step.   In the pulverization step, at least one of a hydrophobic liquid and water and the fly ash are mixed to generate a mixed liquid, and the carbon particles as the hydrophobic particles contained in the mixed liquid are pulverized using beads. The separation method according to claim 15.   The separation method according to claim 16, wherein the diameter of the beads is 1 mm or less.   A method for recovering hydrophilic particles, wherein the hydrophilic particles are recovered from the aqueous phase containing the hydrophilic particles separated using the separation method according to claim 1.   The recovery method of the hydrophilic particle which collect | recovers the said water phase containing the said hydrophilic particle isolate | separated using the separation method as described in any one of Claims 1-17.   A method for recovering hydrophobic particles, wherein the hydrophobic particles are recovered from the hydrophobic liquid phase containing the hydrophobic particles separated by using the separation method according to claim 1.

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