JP6689895B2 - Wet atomization method of raw material and wet atomization apparatus - Google Patents

Description

  The present invention relates to a wet atomization method of a raw material and a wet atomization apparatus.

Fine particles, especially nanoparticles, have a very large specific surface area because their size is in the order of nanometers (nm), and exhibit unique physical properties due to the quantum size effect. Therefore, they have been studied and used in various fields. ing. On the other hand, since nanoparticles easily aggregate, in order to effectively utilize the characteristics of the nanoparticles, it is necessary to carry out an appropriate dispersion treatment suitable for the properties of the nanoparticles.
Meanwhile, the safety of chemical substances is being debated. Particularly in the case of cosmetics, pharmaceuticals, and foods, since the fine particles come into direct contact with the human body or are directly administered to the human body, when the fine particles are atomized, impurities adhere to the fine particles, and if impurities are mixed, safety is guaranteed. It becomes a big problem. In addition, in electronic materials, the inclusion of impurities in fine particles has a considerable adverse effect on electrical characteristics and magnetic characteristics.

  As methods for atomizing the particles, generally known are dispersion by ultrasonic vibration, wet mechanical contact pulverization using a pulverizing medium such as a bead mill, or a method by the same friction pulverization (mechanical contact pulverization method). There is. However, in mechanical contact pulverization using a bead mill or the like, the energy density for pulverization becomes too high because the pulverization medium and particles come into point contact, and the structure of the particle itself is easily broken, and the pulverization medium and particles An excessive temperature rise (heat generation) at the point contact point with causes a problem that the desired functionality of the particles is deteriorated. Furthermore, there is a problem that contaminants (contaminants: also called contaminants) generated from a grinding medium such as a bead mill are mixed.

  On the other hand, the wet jet mill using the water jet technology was developed as a fine atomization method that does not destroy the particles themselves by injecting the raw material solution at a high pressure from a high pressure nozzle and does not mix contamination. Promising as a wet atomization method, it is being put to practical use. However, there is a limit to disperse electrical coagulation only by atomization by a high-pressure wet jet atomizer, that is, dispersion by a physical action such as injection or collision, and it is difficult to obtain nano-sized particles. Therefore, in order to disperse the electric aggregates as described above, the surface charge of the aggregates is adjusted by adding an inorganic acid / inorganic base or an organic acid / organic base to the raw material liquid, and a high pressure wet injection type atomizer There is a method of dispersion. Using this method, nano-sized particles can be obtained, but since the addition of the above-mentioned acid / base is necessary, there may be a problem in that the purity of the raw material as a whole is lowered.

  In recent years, methods of dispersing fine particles in water by various plasma treatments have been studied. The atomization of the agglomerate performed by the conventional high pressure wet injection type atomizer is performed by injecting the raw material liquid containing the agglomerate from the chamber nozzle at a high pressure at a high pressure, but in the in-liquid plasma By generating plasma in the raw material liquid containing the agglomerates of fine particles, the positive and negative charges of the particles are adjusted to disperse the agglomerates and modify the surface to create an environment in which the agglomerates are easily dispersed. ing. The applicant of the present application has proposed, as Patent Document 1, a atomization device in which the high-pressure wet jet atomization device and the in-liquid plasma generation device are combined into one device.

  Patent Document 1 describes that "a high-pressure injection processing device 152 for high-pressure injection from a high-pressure nozzle 41 provided in a chamber 40 and a plasma generator are combined, and electrodes 31 and 32 of the plasma generator are arranged to face each other in the chamber 40. The wet atomization apparatus 100 (FIG. 1) having the above-described configuration, which directly injects the raw material solution 10 containing the agglomerate of fine particles at a predetermined pressure from the high-pressure nozzle 41 to perform in-liquid plasma treatment in the chamber 40. Is listed.

  Japanese Patent Application Laid-Open Publication No. 2004-242242 discloses an electrode for in-liquid plasma that generates plasma in a liquid, including a conductive wire 12 and an insulating member 14 that covers the outer periphery of the conductive wire 12, and the insulating member 14 is the insulating member. The tip end surface 14a of the conductive wire 12 is formed so as to project more toward the tip end side than the tip end surface 12a of the conductive wire 12, and between the inner peripheral surface 14b of the insulating member 14 and the outer peripheral surface 12b of the conductive wire 12. Describes an electrode 10A for in-liquid plasma (FIG. 2) in which an interval d is slidable for the conductive wire 12 (see FIG. 2), and "a tip surface 12a of the conductive wire 12 of the electrode for in-liquid plasma 10A" is described. And the front end surface 12a of the conductive wire 12 of the counter electrode 10B are arranged with a predetermined gap L3. This gap L3 is defined as an inter-electrode distance L3. The inter-electrode distance L3 is, for example, 0.5 mm to 3 mm. Is preferred. ” There is a predicate (see the 0026 paragraph).

Patent Document 3 states that "the first electrode 104 has a shape in which both ends are open (more specifically, a tubular shape such as a cylindrical shape), and the gas supply device is provided in the opening at one end. A gas is supplied into the processing bath 109 from the opening at the other end of the first electrode 104 by the pump 105. The gas supplied from the outside of the processing bath 109 is Air, He, Ar, or O ₂ etc. (paragraph 0011) ”or“ in the description of FIG. 6, a part of the second electrode 202 is in contact with the bubble 206, or It is arranged so that a part thereof is located inside the bubble 206 (paragraph 0056). "

Non-Patent Document 1 describes a high-pressure nozzle as "the erosion amount has two peaks near the nozzle (first peak) and on the downstream side (second peak) due to an increase in the standoff distance" (FIG. 14). See).
In Non-Patent Document 2, regarding a high-pressure nozzle, “the standoff distance s is made dimensionless by the nozzle outlet diameter d, the amount s / d is plotted on the horizontal axis, and the amount of mass reduction of the aluminum test piece by the cavitation jet at each standoff distance is measured. Has been performed ”(see FIG. 15).

JP, 2016-107196, A JP, 2014-167880, A Japanese Patent No. 5362934

Hitoshi Iyama, "Governing Factors in Material Testing and Surface Modification by Cavitation Jet", Japan Society of Water Jet, Vol.15, No.2 (1998) 31-37 Ryoji Kobayashi, et al., “Effect of Nozzle Finishing Accuracy on Cavitation Jet Characteristics,” Japan Society for Water Jet, Vol.15, No.3 (1998), pages 4-8.

  However, even with the methods described in Patent Documents 1, 2, 3 and Non-Patent Documents 1, 2, there are still many problems to be solved in order to stably obtain nanoparticles. That is, in a composite atomizer equipped with a high-pressure wet jet atomizer and a submerged plasma generator, the material is dispersed by high-pressure wet jet, and the surface of the material is reformed by submerged plasma, which is effective. Although the particles are atomized, their surface modifying effect and atomizing effect are limited. Further, since the optimum surface condition for dispersion varies depending on the type of material, it is necessary to change the surface modification method accordingly.

  Therefore, in the present invention, the plasma generated by the submerged plasma generator performs surface modification of the agglomerates in the raw material liquid containing the agglomerates of fine particles, and the particle surfaces after the surface modification are electrically repelled. To provide a high-pressure wet atomization device which utilizes a property that makes it easy to perform, and which has been subjected to surface modification by in-liquid plasma.

An object of the present invention is to perform surface modification in an in-liquid plasma chamber mainly using cavitation bubbles by high-pressure wet injection, to efficiently generate in-liquid plasma, to promote material dispersion, and to improve efficiency. It is an object of the present invention to provide a method and an apparatus capable of performing fine atomization.
Another object of the present invention is to provide a method and an apparatus capable of performing atomization more efficiently than before by performing surface modification suitable for dispersion for each material.

  The inventor of the present application, in addition to the generation of plasma only by cavitation bubbles, more plasma is generated by adding air supply from other sources, resulting in the fact that the efficiency of particle dispersion is increased, and thus a high-pressure injection processing device for high-pressure injection is used. Regarding a wet atomization device combined with an in-liquid plasma generator, by increasing gas supply in addition to controlling the distance between electrodes and the temperature of the raw material solution, it is possible to increase the efficiency of in-liquid plasma generation compared to conventional devices. The present invention has been completed by obtaining the knowledge that surface modification suitable for dispersion and improvement of atomization can be achieved for each material.

The wet atomization device of the present invention is a combination of a high-pressure injection processing device for high-pressure injection from a high-pressure nozzle provided in a chamber and a submerged plasma generator, and has a hollow shape of the submerged plasma generator in the chamber. The electrodes are arranged to face each other, and a gas supply means for supplying a gas from the hollow electrode into the chamber is arranged. A high-pressure nozzle of the high-pressure injection processing apparatus injects a raw material solution to generate plasma. While causing cavitation by the high-pressure injection to the generation area, the gas is supplied by the gas supply means to pass through the hollow-shaped electrode, and the gas is injected toward the facing hollow-shaped electrode. To generate a plasma in the liquid by applying a pulse voltage to the hollow-shaped electrode. In a state filled with the raw material solution to the electrode, and comprises a pump for recirculating the solution, and high-pressure injection of high-pressure nozzles of the high-pressure injection apparatus and repeating a plurality of times the task of the liquid during plasma processing.

According to the present invention, in-liquid plasma can be efficiently generated, and efficient atomization can be performed by performing material dispersion and surface modification.
According to the present invention, it is possible to obtain nano-sized particles that cannot be obtained only by atomization with a high-pressure jet atomizer. According to the present invention, the atomization rate can be increased and the production efficiency can be increased.
According to the present invention, in the atomization of cosmetics, foods, and pharmaceutical raw materials, it is possible to expect the inactivation of bacteria and sterilization effect by plasma at the same time as atomization.
In the wet atomization apparatus and method of the present invention, it is preferable that the operation of high-pressure injection and plasma treatment in the liquid is repeated a plurality of times, whereby the above effects can be improved.

The wet atomization apparatus of the present invention is characterized in that the electrodes are hollow tubes.
The wet atomization method of the present invention is a combination of a high-pressure injection processing device for high-pressure injection from a high-pressure nozzle provided in a chamber and a submerged plasma generator, and a hollow electrode of the submerged plasma generator in the chamber. Are opposed to each other, and gas supply means for supplying gas into the chamber from the electrodes are arranged. The raw material solution is injected from the high pressure nozzle of the high pressure injection processing apparatus, and the gas is supplied by the gas supply means. After passing through the inside of the electrode and injecting gas toward the opposing electrode, a pulse voltage is applied to the electrode to generate in-liquid plasma, and cavitation by high-pressure injection can be applied to the plasma generation area. And
The wet atomization method of the present invention is characterized in that the gas is air or nitrogen.

According to the present invention, the electrode is a hollow tube, and the gas passes through the hollow-shaped (pipe-shaped) electrodes that are arranged to face each other. Since a pulse voltage is applied to the substrate to generate in-liquid plasma, the gas can be efficiently supplied to the same site as the plasma generation site, and the surface modification can be efficiently performed.
According to the present invention, the median diameter (particle size) of particles during atomization can be adjusted by changing the type of gas.
According to the present invention, desired surface modification can be performed by changing the type of gas. For example, nitrogen plasma can be formed by using nitrogen as a gas. Nitrogen plasma can be expected to cure the surface of the material by nitriding the surface of the material. In addition, oxygen plasma using oxygen can be expected to have a hydrophilic effect on the surface of the substance. Further, by using a fluorine compound-based gas, it becomes possible to perform plasma treatment containing fluorine, and a hydrophobizing effect on the surface of the substance can be expected.

The wet atomization method of the present invention is characterized by generating plasma with an interelectrode distance of 1 mm or more and 10 mm or less.
The wet atomization method of the present invention is characterized in that the generation amount of each of O radicals and OH radicals is controlled according to the raw material solution by changing the distance between electrodes between 1 mm and 10 mm.

  According to the present invention, the radical species generated by controlling the distance between the electrodes in the plasma generation part are controlled, and the surface modification suitable for dispersion is performed for each material, so that atomization is performed more efficiently than before. be able to.

The wet atomization apparatus of the present invention is characterized by comprising gas supply means for supplying gas from the electrodes on both sides facing each other.
In the wet atomization method of the present invention, the electrodes are coaxially opposed to each other so that the gas passes through the hollow-shaped electrode, and the gases are ejected opposite to each other so that the gas passes coaxially, thereby causing the opposite collision. Therefore, a pulsed voltage is applied to the electrodes to coaxially generate in-liquid plasma, and cavitation due to high-pressure injection is exerted on the plasma generation area.

  According to the present invention, the dispersion effect is improved by supplying the gas from the electrodes on both sides facing each other. In addition, the electrodes are coaxially opposed to each other, and the gas is passed through the hollow-shaped electrode, so that the gas is jetted oppositely so as to pass coaxially and the gas collides with each other, so that the gas is more effectively dispersed. You can Furthermore, since plasma in liquid can be generated coaxially and cavitation due to high-pressure injection can be exerted, the dispersion effect is improved.

According to the present invention, an in-liquid plasma can be efficiently generated in an in-liquid plasma chamber mainly using cavitation bubbles by high pressure wet injection, and efficient atomization can be achieved by performing material dispersion and surface modification. It can be performed.
According to the present invention, surface modification such as nitrogen plasmaization, hydrophilization, and hydrophobization can be performed depending on the supplied gas.
According to the present invention, by controlling the distance between electrodes in the plasma generation part, the generated radical species are controlled, and surface modification suitable for dispersion is performed for each material, resulting in more efficient atomization than in the past. It can be carried out.

It is a block diagram which illustrates the schematic structure of the wet atomization apparatus of embodiment of this invention. FIG. 3 is a structural diagram illustrating a high pressure nozzle and a chamber according to the above embodiment. It is a structural diagram which illustrates the inclination angle of a high pressure nozzle and a chamber concerning the above-mentioned embodiment. It is a principal part enlarged view of the chamber which concerns on the said embodiment. It is a principal part enlarged view explaining the space | interval adjustment means and electrode distance adjustment method which concern on the said embodiment. It is a principal part enlarged view which illustrates the submerged plasma generation location which arises when the submerged plasma generator which concerns on the said embodiment is made of metal. FIG. 6 is a structural diagram illustrating another high pressure nozzle and chamber according to the above embodiment. FIG. 6 is a structural diagram illustrating another high pressure nozzle and chamber according to the above embodiment. It is a manufacturing-process flowchart which illustrates the manufacturing procedure of embodiment of this invention. 5 is a particle size distribution chart of a sample processed under each experimental condition according to Example 2. FIG. 5 is a particle size distribution chart of a sample processed under each experimental condition according to Example 3. FIG. FIG. 9 is a structural diagram illustrating a high pressure nozzle and a chamber in which an electrode pair according to Example 5 is obliquely arranged toward the raw material IN side. FIG. 10 is a structural diagram illustrating a high pressure nozzle and a chamber in which an electrode pair according to Example 5 is obliquely arranged toward the raw material OUT side. It is a graph which shows the relationship between the normalized standoff distance and the amount of erosion. 7 is another graph showing the relationship between the normalized standoff distance and the amount of erosion.

  Modes for carrying out the present invention will be described below.

(Embodiment)
The raw materials of this embodiment will be described. In the present invention, the raw material is an aggregate of fine particles. Examples of the raw material include metal fine particles, metal oxide fine particles, nanofibers, and other known fine particles. Examples of the raw material of the metal oxide include titanium oxide, barium titanate, ferrite, alumina, silica, zirconia, and other known metal oxide fine particle aggregates. Examples of the nanofibers include cellulose, chitin, chitosan, silk, and other known biomass nanofibers, which are biomass raw materials (biologically-derived polymers, particularly water-insoluble polymer raw materials). Other known fine particles include, for example, carbon nanotubes (CNTs). Further, applications of the atomization method and apparatus of the present invention include atomization of raw materials in various material fields such as pharmaceuticals, electronic parts, pigments, cosmetics, foods and agricultural chemicals. For example, examples of the drug raw material include aggregates of phenytoin, magnesium hydroxide, caffeine, calcium carbonate, bidroxypropyl cellulose, magnesium stearate, and acetaminophen. Further, an additive having at least one of an electrostatic repulsion action and a steric hindrance action to the fine particles may be added.
When the raw material is subjected to the high-pressure injection treatment by the high-pressure injection treatment apparatus according to the present invention, for example, the biomass raw material becomes entangled and thinned while keeping the length of the fibers. Then, by changing processing conditions such as the injection pressure of the high-pressure injection processing device and the number of times of processing, it is possible to cut the fibers or reduce the molecular weight. In the present invention, the nanofiber means a fiber having a nanosize width.

  In the present invention, the raw material solution 10 is a liquid containing an aggregate of particles. The solvent of the raw material solution 10 is water, IPA or a known aqueous solution.

  Wet atomization apparatus 100 of the present embodiment will be described. FIG. 1 is a block diagram showing a schematic configuration of a wet atomization apparatus 100 according to an embodiment of the present invention.

  The wet atomization apparatus 100 of the present embodiment includes a high pressure nozzle 41 for high pressure injection of the raw material solution 10 containing an aggregate of particles, and a plasma generator 160 including electrodes 31 and 32. The nozzle 41 is provided in the chamber 40, the electrodes 31 and 32 are arranged to face each other in the chamber 40, and the wet atomization apparatus 100 is arranged at a position where cavitation due to high-pressure injection reaches a plasma generation region between the electrodes 31 and 32. The electrodes 31 and 32 are provided with gas supply means 180 for supplying and injecting gas toward the electrodes 32 and 31 facing each other (FIG. 1). The gas supply unit 180 has a valve 181, and supplies gas from the electrodes 31 and 32 on opposite sides by the opening operation of the valve 181. The gas used is not particularly limited and is, for example, air or nitrogen. Reference numeral 80 is a pump for refluxing the solution subjected to the in-liquid plasma treatment.

  The high-pressure injection processing device 152 includes a hydraulic pressure generation and control unit 101 for hydraulically driving and controlling the high-pressure pump 102, a raw material tank 103 for charging the raw material solution 10, a high pressure pump 102 for pressurizing the raw material solution 10, and a high pressure injection and pressurization. It comprises a chamber 40 for spraying and accelerating the particles 1a in the raw material solution 10 to make the particles 1a fine and to disperse them, and a heat exchanger 105 for cooling the treatment liquid. As the high-pressure injection processing device 152, for example, a water jet developed by Sugino Machine Co., Ltd. is used, the pressure of the high-pressure injection is 100 to 245 MPa, the injection speed is 440 to 700 m / s, and the raw material solution 10 is a high pressure nozzle. It is possible to atomize and disperse by injecting at a higher pressure than 41, but it is not limited to this.

  The plasma generator 160 includes a plasma generating power supply 30 and electrodes 31 and 32. Plasma electrodes 31 and 32 are arranged to face each other in the liquid in the chamber 40, and are electrically connected to the plasma generating power source 30, respectively.

(Wet atomization method of the present embodiment)
In the present embodiment, a chamber 40, a high-pressure injection processing device 152 for high-pressure injection from a high-pressure nozzle 41 provided in the chamber 40, and an in-liquid plasma generation device 160 are combined (FIG. 1). The hollow electrodes 31 and 32 of the submerged plasma generator 160 are arranged opposite to each other in the chamber 40 so that the cavitation due to the high-pressure jet reaches the plasma generation area between the electrodes 31 and 32. The gas supply means 180 for supplying the gas into the chamber 40 is disposed. In the wet atomization method of the present embodiment, the raw material solution 10 is jetted from the high pressure nozzle 41 of the high pressure jet processing apparatus 152, and gas is supplied by the gas supply means 180 to pass through the electrodes 31, 32.

  FIG. 2 is a structural diagram of the high pressure nozzle 41 and the chamber 40 of the wet atomization apparatus 100 according to this embodiment. In-chamber plasma treatment of the raw material solution 10 is performed in the chamber 40.

  The electrodes 31 and 32 are hollow tubes, and the electrodes 31 and 32 are arranged on the same axis A so as to face each other (FIG. 2). The gas supplied from the gas supply means 180 shown in FIG. 1 is divided into two parts so as to pass through the hollow electrodes 31, 32 (FIG. 2). Then, the gas is ejected toward the electrodes 32, 31 facing each other. That is, the gas that has passed through the electrode 31 is supplied into the chamber by being ejected from the hollow tube outlet of the electrode 31 toward the electrode 32, and the gas that has passed through the electrode 32 is the hollow tube outlet of the electrode 32. It is supplied into the chamber by being ejected from the electrode toward the electrode 31. Gases injected oppositely from inside the electrodes 31, 32 are injected so as to pass on the same axis A and collide oppositely in the plasma generation area. Then, a pulse voltage is applied to the electrodes 31 and 32 to generate in-liquid plasma, and cavitation due to the high-pressure injection is exerted on the plasma generation area. In this way, cavitation is caused by high-pressure injection of the raw material solution 10 from the high-pressure nozzle 41, and the raw material solution 10 is subjected to in-liquid plasma treatment by causing the cavitation to reach the plasma generation area supplied with gas. The raw material solution 10 that has been subjected to the in-liquid plasma treatment under the gas supply is received by the jet flow receiver 40 a and then discharged from the outlet 42. The work of high-pressure injection and plasma treatment in liquid is repeated a plurality of times. Note that the symbol P1 schematically shows plasma discharge. Reference numeral C1 is a cavitation bubble, and reference numeral D1 is a supplied gas bubble.

  FIG. 3 is a structural diagram of the high pressure nozzle 41 and the chamber 40 of the wet atomizer 100, and is a diagram for explaining the injection direction of the raw material solution 10 injected from the high pressure nozzle 41.

  The injection direction of the high-pressure nozzle 41 of the wet atomizer 100 is preferably such that the inclination angle α is 5 to 20 degrees, more preferably the inclination angle α is 10 to 15 degrees. The inclination angle α is an angle formed by the horizontal plane L and the jetting direction M, for example, 0 degree when the horizontal plane L and the jetting direction M are the same, and 90 degrees when the horizontal plane L and the jetting direction M are vertical. .

  In the case of a nozzle (orifice flow) such as a cavitation jet, the cavitation coefficient σ, which is the controlling factor of the cavitation jet, is the nozzle upstream pressure (upstream pressure in the chamber 40) Po, the nozzle downstream pressure (in the chamber 40). Downstream pressure) Pa and the saturated vapor pressure Pv of the raw material solution 10 are defined by the following equation 1.

(Equation 1)
σ = ((Pa−Pv) / (Po−Pa)) ≈Pa / Po

  In the cavitation jet, since Po >> Pa >> Pv, cavitation coefficient σ≈nozzle downstream pressure Pa / nozzle upstream pressure Po can be simplified as shown in Equation 1.

  When the jetting direction M is tilted with the tilt angle α set to 90 degrees (vertical direction), the fluid is hard to escape from the chamber, and the pressure is retained. That is, as the inclination angle α increases, the nozzle downstream pressure Pa increases and the cavitation coefficient increases. In this way, cavitation is less likely to occur and bubbles are less likely to occur. On the other hand, when the inclination angle α is 0 degree (horizontal direction), the fluid easily flows, and the bubbles that should be generated in the water atmosphere are less likely to be generated. For the above reasons, the inclination angle α is preferably 5 to 20 degrees, more preferably 10 to 15 degrees.

(Regarding the electrode arrangement of this embodiment)
It is preferable that the wet atomization apparatus 100 of the present invention includes interval adjusting means 33, 34 that can control the inter-electrode distance S1 as shown in FIG. By controlling the inter-electrode distance S1 in the plasma generation part, the generated radical species are controlled, and surface modification suitable for dispersion is performed for each material, whereby atomization can be performed more efficiently than in the past.

  The plasma electrode 31 is provided with a space adjusting means 33, which can adjust the inter-electrode distance S1 between the plasma electrode 31 and the plasma electrode 32 which is arranged oppositely (FIG. 2). Similarly, the plasma electrode 32 is provided with a gap adjusting means, and the inter-electrode distance S1 between the plasma electrode 32 and the plasma electrode 31 oppositely arranged can be adjusted. Thereby, atomization can be performed according to the raw material solution 10.

  The electrode-to-electrode distance S1 is set to 1 mm or more and 10 mm or less to generate electrodes and generate plasma to generate H radicals and OH radicals in the plasma generation area. By changing the inter-electrode distance S1 between 1 mm and 10 mm, the respective amounts of O radicals and OH radicals generated are controlled in accordance with the type of the raw material solution 10 to obtain optimum atomization conditions. It is preferable to control the generation amount of O radicals and OH radicals, which can control the pH of the raw material solution 10 and promote atomization, which has the effect of changing various characteristics of the raw material solution 10. In the cellulose solution, the particle size, viscosity, pH, etc. of the raw material can be changed. With titanium oxide, silica, and carbon nanotubes, the particle size, zeta potential, and pH of the raw material can be changed. Further, for example, even between particles having strong cohesive force or particles having poor wettability, it is possible to make nano-sized particles by stepwise atomizing by repeating the operation of high-pressure jetting and plasma treatment in liquid a plurality of times. It will be easy.

When the raw material solution 10 is cellulose, it is preferable that the distance S1 between the electrodes 31 and 32 is set to 2 mm or more and 10 mm or less to generate OH radicals, and the reaction of the OH radicals causes a lowering of the molecular weight of cellulose to be atomized. .
OH radicals are effective for materials forming polymers by hydrogen bonding such as cellulose (cellulose nanofibers), and therefore the inter-electrode distance S1 of in-liquid plasma is preferably 2 mm or more.

When the raw material solution 10 is titanium oxide, the inter-electrode distance S1 between the electrodes 31 and 32 is set to 1 mm or more and 2 mm or less to generate H radicals, and the pH of the raw material solution 10 is shifted from the isoelectric point of titanium oxide to the acidic side. It is preferable that the particle surface of titanium oxide is changed to a positively charged state, and electrostatic repulsion force is generated between the particles to atomize the particles.
When the raw material solution 10 is silica, the electrode distance S1 between the electrodes 31 and 32 is set to 2 mm or more and 10 mm or less to generate OH radicals, and the pH of the raw material solution 10 is shifted from the isoelectric point of silica to the basic side. It is preferable that the surface of the particles is changed to a state of being negatively charged, and electrostatic repulsive force is generated between the particles to atomize the particles.
Metal oxides such as titanium oxide and silica have different radicals effective for atomization for each isoelectric point peculiar to the material. Since H radicals are effective in atomizing titanium oxide having an isoelectric point of pH 6, the inter-electrode distance S1 of in-liquid plasma is preferably 2 mm or less. Since OH radicals are effective for atomization in silica having an isoelectric point in the vicinity of pH 2 to 3, it is desirable to set the inter-electrode distance S1 of the in-liquid plasma to 2 mm or more.

When the raw material solution 10 is carbon nanotubes (CNT), H radicals are generated by setting the inter-electrode distance S1 of the electrodes 31 and 32 to 1 mm or more and 2 mm or less, and a radical substitution reaction is caused between the H radicals and the carbon nanotubes to form fine particles. Preferably.
In a material such as CNT that does not have polarity on the surface of the material and is not well compatible with water, hydrophilization with H radicals is effective for atomization, and therefore the inter-electrode distance S1 of in-liquid plasma is preferably 2 mm or less.

  FIG. 4 is an enlarged view of a main part of the chamber 40 of this embodiment. The chamber 40 (plasma chamber) is configured to inject the raw material solution 10 into the liquid from the high-pressure nozzle 41 to accelerate particles to generate cavitation C1 and discharge the suspension 20 from the outlet, but is not particularly limited. Preferably, one end of a high-pressure injection processing device 152 having an orifice nozzle as the high-pressure nozzle 41 and a main part of the submerged plasma generation device 160 are combined into a chamber, and an electrode distance S1 of the electrode pair 31, 32 is set. , And an observation window 60 for adjusting the position (FIG. 4).

  FIG. 5 is a diagram showing an example of the inter-electrode distance adjustment procedure of the present embodiment. The inter-electrode distance adjustment procedure is performed by first moving the scale bar 70 from the OUT side of the suspension 20 toward the hollow electrode pair 31, 32 while the high-pressure injection processing device 152 and the submerged plasma generation device 160 are stopped. Insert the (reference rod). Then, while looking through the observation window 60, the scale bar 70 is arranged at an intermediate position between the electrode pairs 31 and 32, and the electrode pairs 31 and 32 are pressed toward the scale bar 70. Then pull out the scale bar. The procedure of adjusting the distance between the electrodes and the distance between the electrodes is not particularly limited to this content. For example, the distance between the electrodes can be adjusted by sliding the electrodes by the distance adjusting means or by using the nozzle as the distance adjusting means. May be adjusted, or in addition to manual operation, a method of electrically driving by a motor to adjust the inter-electrode distance may be used.

  FIG. 6 is a diagram showing in-liquid plasma generated when the in-liquid plasma generator 160 of the present embodiment is made of metal. When the submerged plasma generator 160 is made of metal, particularly when the inter-electrode distance is large, normal plasma P1 is generated and unintentional plasma P2 is generated between the electrode 31 or 32 and the submerged plasma generator 160. May generate plasma (Fig. 6). When energization of the in-liquid plasma generator 160 occurs, there is a risk of electric shock to the operator of the apparatus. Therefore, the in-liquid plasma generator 160 is preferably made of an insulating material, more preferably resin (PTFE) in order to prevent electric shock. The high-pressure nozzle 41 (orifice nozzle) is preferably made of, for example, single crystal diamond in order to withstand high-pressure injection, and the high-pressure injection processing device 152 is preferably made of stainless steel (FIGS. 4 and 5).

  As the chamber 40, a single nozzle chamber, an oblique collision chamber, a ball chamber, or the like is used. As shown in FIGS. 1 and 2, the single nozzle chamber is a type of chamber in which the raw material solution 10 is injected from one nozzle 41 into the liquid to accelerate the particles 1 a and discharge the suspension 20 from the outlet 42. In the single nozzle chamber, atomization and dispersion are performed by the shearing force when the particles pass through the nozzle 41 and the cavitation impact force due to the submerged injection. In the oblique collision chamber, the raw material solution is injected into the liquid from a pair of nozzles that are arranged to face each other so as to obliquely collide, and the particles are accelerated to obliquely collide with each other (face-to-face collision), and the suspension is discharged from the outlet. It is the type to do. The ball chamber is a type in which a raw material solution is injected into a liquid from a nozzle to accelerate particles to collide with a ceramic ball made of silicon nitride or the like, and a suspension is discharged from an outlet.

  In FIG. 7, a plurality of hollow plasma electrodes 31 (31a, 31b, 31c) and a plurality of hollow plasma electrodes 32 (32a, 32b, 32c) are arranged facing each other at a predetermined interval in a chamber 40 to which a high-pressure nozzle 41 is directly connected. The configuration is shown. The single nozzle chamber 40 including the plurality of plasma electrodes 31 and 32 is more efficient than the single nozzle chamber 40 including the single plasma electrode pair of FIG. 2 by disposing the plurality of plasma electrodes 31 and 32 facing each other. To atomize.

  Each plasma electrode 31 (31a, 31b, 31c) is provided with a space adjusting means 33 (33a, 33b, 33c), and a plasma electrode 32 (32a, 32b) paired with each plasma electrode 31 (31a, 31b, 31c). , 32c) also includes the interval adjusting means 34 (34a, 34b, 34c). The inter-electrode distances S1 are adjusted according to the type of the raw material solution 10 to control the generation amount of H radicals and OH radicals according to the type of the raw material solution 10. Therefore, by having a plurality of interval adjusting means 33 (33a, 33b, 33c), 34 (34a, 34b, 34c), it is possible to perform more optimal atomization control than the chamber 40 of FIG. 2 having only one plasma electrode pair. To do.

  For example, when the raw material solution 10 is cellulose or silica, the plurality of inter-electrode distances S1 are all set to 2 mm or more and 10 mm or less to more effectively atomize the particles. Further, in the case of the raw material solution 10 in which a plurality of solutions such as cellulose, titanium oxide, and CNT are mixed, the atomization is efficiently performed by changing the inter-electrode distance S1 for each electrode pair. For example, the inter-electrode distance between the plasma electrodes 31a and 32a is set to 1 mm or more and 2 mm or less, which is the optimum inter-electrode distance for atomizing titanium oxide or CNT, by the space adjusting means 33a and 34a, and the plasma is generated by the space adjusting means 33b and 34b. The distance between the electrodes 31b and 32b is set to 2 mm or more and 10 mm or less, which is the optimum distance between the electrodes of cellulose. The interval adjusting means 33, 34 may drive the electrodes arranged opposite to each other synchronously or independently. Further, the plasma electrodes 31 and 32 may be positioned near the side wall of the chamber 40 to generate plasma, or may not have a space adjusting means.

  FIG. 8 is a structural diagram illustrating another high pressure nozzle and chamber according to the present embodiment, and is a diagram showing the distance between the electrode pair 31 and 32 from the high pressure nozzle injection port and a mechanism for controlling the distance. . The electrode pairs 31 and 32 can be moved along the direction of the jet flow of the raw material solution (direction perpendicular to the axis A of the electrode pair). The lateral movement of the electrode pairs 31 and 32 in FIG. 8 may be performed by the space adjusting means 33 and 34, or may be performed by providing another control mechanism. The distance adjusting means 33, 34 vertically move the electrode pairs 31, 32 to adjust the distance between the electrode pairs 31, 32, and the distance adjusting means 33, 34 also move the electrode pairs 31, 32 laterally. By making it possible, the device can be downsized.

  Non-Patent Document 1 and Non-Patent Document 2 relate to a high-pressure nozzle, and a stand-off distance s (distance from a nozzle injection port to a processed sample) and a nozzle outlet diameter d are used. The relationship between the normalized standoff distance (normalized standoff distance: s / d), which is the normalized amount, and the erosion amount is shown in the form of a graph (see FIGS. 14 and 15). According to these documents, "the erosion amount has two peaks near the nozzle (first peak) and on the downstream side (second peak) due to an increase in the standoff distance". At the first peak, erosion is high mainly due to the energy of jetting, and at the second peak, erosion is caused by the cavitation that has occurred. From this, in the present invention, regarding the arrangement of the high-pressure nozzles, by disposing the plasma electrodes 31 and 32 at positions where these peaks are removed, damage to the electrodes can be suppressed.

  However, since the erosion of the second peak is caused by the generated cavitation, many bubbles are generated at the second peak. Therefore, if the plasma electrodes 31 and 32 are arranged at the position where the second peak is removed, damage to the electrodes 31 and 32 can be suppressed, but the plasma generation efficiency is reduced and the atomization efficiency is reduced.

  Therefore, in consideration of plasma generation efficiency and atomization efficiency, the plasma electrodes 31 and 32 may be arranged at the first peak and the second peak of cavitation. In particular, the electrodes 31 and 32 may be arranged at the position of the second peak to generate plasma. Since many bubbles are generated at the second peak, plasma is generated at the second peak having many bubbles, so that reduction in plasma generation efficiency is suppressed and reduction in atomization efficiency is suppressed.

  Furthermore, when arranging the electrodes 31 and 32 at the second peak, by making the electrodes 31 and 32 into an erosion resistant material or an erosion resistant shape, or by attaching an erosion preventing member to the electrodes 31 and 32, It is possible to provide a wet atomization device that suppresses damage to the plasma electrodes 31 and 32, suppresses a decrease in plasma generation efficiency, and suppresses a decrease in atomization efficiency. The erosion resistant material is an electrode material that suppresses erosion, such as titanium, stainless steel, or tungsten. The erosion resistant shape is an electrode shape that suppresses erosion, such as a columnar shape or a polygonal shape. The erosion prevention member is a member for preventing erosion of the electrodes 31 and 32, and is, for example, cemented carbide, zirconia, or alumina.

  The method for producing the dispersion liquid of the present embodiment will be described. FIG. 9 is a manufacturing process flow chart showing a manufacturing procedure of a dispersion liquid in which fine particles of the embodiment of the present invention are dispersed. The method for producing a dispersion liquid of the present invention includes steps S12 and S20. In the present embodiment, the raw material solution 10 containing the agglomerates of fine particles is high-pressure jetted at a predetermined pressure from the high-pressure nozzle 41 of the high-pressure jetting treatment apparatus 152 shown in FIG. 1, and gas is supplied immediately while causing cavitation in the chamber 40. Plasma treatment in liquid is performed below (step S12). Then, in accordance with the degree of dispersion of the fine particles, the high pressure nozzle 41 of the high pressure injection processing device 152 performs high pressure injection of the raw material solution 10 at a predetermined pressure to perform in-liquid plasma processing in the chamber 40 repeatedly (steps). S20).

  Examples of the present invention will be described below.

  The wet atomization apparatus 100 of this embodiment is as shown in FIGS. As the high-pressure injection processing device 152 (abbreviation: SBS), Starburst HJP25005 (5.5 kw) (manufactured by Sugino Machine Ltd.), which is a method of causing a slurry solution jet flow to collide with a hard sphere, was used. The injection pressure was 245 MPa. As the plasma generating power source 30 (abbreviation: SP), MPP-HV01 for pulse plasma (manufactured by Kurita Manufacturing Co., Ltd.) was used. The maximum voltage was 6 kV, the frequency was 30 kHz, and the pulse width was 1.5 μs. The chamber 40 was a submerged plasma chamber, the high-pressure nozzle 41 provided in the chamber 40 was a single nozzle, and the nozzle diameter was φ0.14 mm. The hollow electrode pair 31, 32 of the chamber 40 is located in the liquid, and the inter-electrode distance S1 is set to 1 mm. The gas supplied to the gas supply means 180 was selected from nitrogen, air, argon and oxygen.

  The wet atomization method and / or the dispersion liquid manufacturing method of the present embodiment are performed by the following procedure. 1) A solvent (ion-exchanged water or the like) and a solute (titanium oxide powder or zirconia powder) are suspended and well stirred to prepare the raw material solution 10. 2) The inter-electrode distance S1 of the plasma chamber 40 is set to an interval of 1 mm. 3) Put the raw material solution 10 in the raw material tank 103 of the star burst 152, and operate the star burst 152 at a predetermined set pressure value. 4) It is visually confirmed that the hollow electrodes 31 and 32 in the chamber 40 are filled with the liquid, gas is supplied (jetted), and the plasma generating power supply 30 is operated at a predetermined set value. During this period, 200 mL of the initial discharge liquid, which is the dead volume in the device, is discarded. 5) After discarding, the processed sample is accumulated in another tank, and at the same time when the raw material tank 103 becomes empty, the sample in another tank is returned to the raw material tank 103. 6) After returning, the processed sample is accumulated, and after reaching the dead volume (about 200 mL), it is judged that the one-pass processing is completed by returning this to the raw material tank. 7) The total time required for the above procedure 5) and procedure 6) is measured, and the number of subsequent passes is managed by time. 8) At the time of 10 passes, sample the treated sample in another container (about 10 mL). 9) Collect raw materials in a separate container on the 30th pass. 10) Using 0-pass, 10-pass, and 30-pass sampling liquids, particle size distribution measurement, median diameter, and pH measurement are performed.

(Example 1)
The submerged plasma chamber 40 is configured so that a gas can be sent from the outside to the plasma generating portion through the hollow electrodes 31 and 32 as shown in FIG. In the present embodiment, the optimum gas for the submerged plasma chamber 40 was selected by investigating how the dispersibility changes depending on the type of gas sent to the plasma generation part. Argon, oxygen, nitrogen, and air were prepared as the gas to be sent, and the dispersion effect was verified using titanium oxide particles and zirconia particles as raw materials. The components of air are nitrogen 78.08%, oxygen 20.95%, argon 0.93%, and carbon dioxide 0.03%.

Table 1 shows the median diameter of each raw material according to the type of gas sent into the submerged plasma chamber 40. As the sampling liquid, the one that was processed 30 times was used for the measurement. As a result, the median diameter changed depending on the type of gas.

(Example 2)
In the in-liquid plasma, various active species are generated by the reaction between the generated plasma and various gases. For example, the reaction between plasma and oxygen produces active oxygen species such as ozone and hydrogen peroxide, and the reaction between plasma, nitrogen and oxygen produces nitric oxide. In this test, it was investigated how various analysis results change by processing while feeding N ₂ into the submerged plasma chamber 40.
As Example 2, atomization of titanium oxide powder was performed. No. 1-No. The raw material solution 10 (atomization material) used in 5 was a titanium oxide solution having a concentration of 1 wt% and a treatment amount of 600 mL, in which 6 g of titanium oxide P25 powder (manufactured by Degussa) was used as a solute and 594 g of ion-exchanged water was used as a solvent. Was used. The processing conditions of in-liquid plasma and high-pressure injection are as follows: injection pressure of 245 MPa, 30 passes (0 pass, 10 passes, 30 passes, sample of processed sample is sampled, measurement is performed using each sampling liquid), electrode The distance was 1 mm, the pulse width was 1.5 μs, the gas flow rate was 2 L / min, and the chamber nozzle diameter was φ0.14 mm. The test circuit is shown in FIG.

  Table 2 shows the results of particle size distribution measurement and pH measurement when the atomization treatment was performed while supplying various gases. The measured values are the median diameter (nm) and pH change of titanium oxide before and after the treatment, and were measured by a dynamic scattering particle size distribution device (Zetasizer Nano ZS, Spectris Co., Ltd.). In the 0 pass, the median diameter is not stable because the particles settle down quickly, and the dispersion occurs between about 400 and 4000 nm.

  No. 1-No. Various gases were supplied to the gas supply means 180 up to 4, and the supplied gas was nitrogen (No. 1), air (No. 2), argon (No. 3), and oxygen (No. 4). The components of air are nitrogen 78.08%, oxygen 20.95%, argon 0.93%, and carbon dioxide 0.03%. No. 1-No. The chamber of No. 4 was an in-liquid plasma chamber. No. No. 5 is a comparative example in which no gas was supplied and only high pressure injection was performed and plasma was not generated. Specifically, this is an example in which the high-pressure injection processing device 152 is used, the plasma generation device 160 is not used as the chamber 40, and a ball chamber is used.

  In the second embodiment, No. 1-No. As shown in FIG. 4, atomization of particles was confirmed with each gas, and it was confirmed that atomization proceeded by gas supply. It was also confirmed that the difference in dispersion effect can be obtained by changing the type of gas supplied to the submerged plasma chamber. From this, it was confirmed that the atomization size can be adjusted by selecting the type of gas to be supplied.

  Further, a particle size distribution chart of the 30-pass sample under each condition is shown in FIG. It is a particle size distribution chart of SBS simple substance processing and SBS-plasma composite processing in a liquid, and the dynamic scattering type particle size distribution meter was used for the measurement. As shown in Table 2 and FIG. 10, in this example, a difference in dispersion effect was confirmed by changing the type of gas fed into the submerged plasma chamber. Atomization of particles was confirmed in each gas.

(Example 3)
As Example 3, zirconia powder was atomized. No. 6-No. The raw material solution 10 (atomization material) used in 10 was a zirconia solution having a concentration of 1 wt% and a treatment amount of 600 mL, in which a solute was suspended as 6 g of zirconia nanopowder and a solvent was suspended as 594 g of ion-exchanged water. The processing conditions of in-liquid plasma and high-pressure injection are as follows: injection pressure of 245 MPa, 30 passes (0 pass, 10 passes, 30 passes, sample of processed sample is sampled, measurement is performed using each sampling liquid), electrode The distance was 1 mm, the pulse width was 1.5 μs, the gas flow rate was 2 L / min, and the chamber nozzle diameter was φ0.14 mm. The test circuit is shown in FIG.

  Table 3 shows the results of particle size distribution measurement and pH measurement when the atomization treatment was performed while supplying various gases. The measured values are the median diameter (nm) of zirconia and the pH change before and after the treatment, and were measured by a dynamic scattering particle size distribution device (Zetasizer Nano ZS, manufactured by Spectris). In the 0 pass, the median diameter is not stable because the particles settle down quickly, and the dispersion occurs between about 400 and 4000 nm.

  No. 6-No. Up to 9, various gases were supplied to the gas supply means 180, and the supplied gases were nitrogen (No. 6), air (No. 7), argon (No. 8), and oxygen (No. 9). The components of air are nitrogen 78.08%, oxygen 20.95%, argon 0.93%, and carbon dioxide 0.03%. No. 6-No. The chamber 9 was an in-liquid plasma chamber. No. No. 10 is a comparative example in which no gas was supplied and only high pressure injection was performed and plasma was not generated. Specifically, this is an example in which the high-pressure injection processing device 152 is used, the plasma generation device 160 is not used as the chamber 40, and a ball chamber is used.

  In Example 3 as well, No. 6-No. As shown in FIG. 9, atomization of particles was confirmed with each gas, and it was confirmed that atomization proceeded by gas supply. It was also confirmed that the difference in dispersion effect can be obtained by changing the type of gas supplied to the submerged plasma chamber. From this, it was confirmed that the atomization size can be adjusted by selecting the type of gas to be supplied. Also in the case of the zirconia powder of Example 3, the same results as in the case of the titanium oxide powder of Example 2 were obtained, so that even if the atomizing material is changed, the atomization promoting effect and the atomizing size adjusting effect can be obtained. It was confirmed.

  Further, FIG. 11 shows a particle size distribution chart of the 30-pass sample under each condition. It is a particle size distribution chart of SBS simple substance processing and SBS-plasma composite processing in a liquid, and the dynamic scattering type particle size distribution meter was used for the measurement. As shown in Table 3 and FIG. 11, in this example, a difference in dispersion effect was confirmed by changing the type of gas fed into the submerged plasma chamber. Atomization of particles was confirmed in each gas.

(Example 4)
As Example 4, atomization was performed by changing the gas supply method and the gas supply amount. In this example, the relationship between the method of using the hollow electrodes 31 and 32 in the submerged plasma chamber 40 and the gas supply amount was confirmed, and the optimum dispersion condition of the submerged plasma chamber 40 was confirmed.

  In the fourth embodiment, No. 11 to No. The high pressure jet processor 152 and plasma generator 160 were used in all 16 samples. The processing conditions for in-liquid plasma and high-pressure injection are as follows: injection pressure 245 MPa, number of passes 30 times (sampling of the processed sample is performed every 10 passes, measurement is performed using each sampling liquid), pulse width 1.5 μs, The nozzle diameter of the chamber was 0.14 mm. The gas supplied to the gas supply means 180 was air. The components of air are nitrogen 78.08%, oxygen 20.95%, argon 0.93%, and carbon dioxide 0.03%. No. 11 to No. The 16 chambers were submerged plasma chambers 40. The test circuit is shown in FIG.

In the case of titanium oxide solution In Table 4, a titanium oxide solution is used as the raw material solution 10 (atomization material), and the atomization treatment by the submerged plasma chamber 40 is performed while changing the gas supply method and the supply amount. The results of particle size distribution measurement and pH measurement are shown. No. 11-No. Specifically, the titanium oxide solution of the raw material solution 10 used in 13 was prepared by suspending 6 g of a solute of titanium oxide P25 powder (manufactured by Degussa) and 594 g of ion-exchanged water as a solvent, a concentration of 1 wt%, and a treatment amount of 600 mL. The titanium oxide solution of was used. The distance between the electrodes was 1 mm. The measured values are the median diameter (nm) and pH change of titanium oxide before and after the treatment, and were measured by a dynamic scattering particle size distribution device (Zetasizer Nano ZS, Spectris Co., Ltd.). In the 0 pass, the median diameter is not stable because the particles settle down quickly, and the dispersion occurs between about 400 and 4000 nm.

  The gas supply method and the gas flow rate are No. 11 to No. Changed with 13. The gas supply method was changed depending on whether the gas supply plasma electrode was one (one of the electrode pairs) or both (electrode pair). In No. 11, gas was supplied only from one electrode (either one of the electrode 31 and the electrode 32), and the gas flow rate was set to 1.5 L / min. No. In No. 12, gas was supplied from both electrodes (both electrodes 31 and 32), and the gas flow rate was 1.5 L / min. No. In No. 13, gas was supplied from both electrodes (both electrodes 31 and 32), and the gas flow rate was 3.0 L / min.

  As shown in Table 4, No. 11 and No. 12, the median diameter is No. 12 regardless of the number of passes. No. 11 rather than No. 12 is smaller. By supplying gas from both electrodes 31, 32, the dispersion effect of the submerged plasma chamber 40 can be improved. No. 12 and No. When comparing No. 13, the median diameter is No. No. 12 13 is smaller. By doubling the gas supply amount, the dispersion effect of the submerged plasma chamber 40 can be further improved. It is considered that by increasing the gas supply amount, the bubbles necessary for the generation of submerged plasma increased, and the generation rate of submerged plasma increased.

In the case of zirconia solution In Table 5, the zirconia solution is used as the raw material solution 10, and the particle size distribution measurement result and the pH measurement are performed when the atomization treatment is performed by the submerged plasma chamber 40 while changing the gas supply method and the supply amount. The results are shown. No. 14-No. Specifically, the zirconia solution of the raw material solution 10 (atomization material) used in 16 is a zirconia having a concentration of 1 wt% and a treatment amount of 600 mL in which the solute is suspended as 6 g of zirconia nanopowder and the solvent is 594 g of ion-exchanged water. The solution was used. The distance between the electrodes was 5 mm. The measured values are the median diameter (nm) of zirconia and the pH change before and after the treatment, and were measured by a dynamic scattering particle size distribution device (Zetasizer Nano ZS, manufactured by Spectris). In the 0 pass, the median diameter is not stable because the particles settle down quickly, and the dispersion occurs between about 400 and 4000 nm.

  The gas supply method and the gas flow rate are No. 14 to No. Changed at 16. The gas supply method was changed depending on whether the gas supply plasma electrode was one (one of the electrode pairs) or both (electrode pair). In No. 14, gas was supplied only from one electrode (either one of the electrode 31 and the electrode 32), and the gas flow rate was set to 1.5 L / min. No. In No. 15, gas was supplied from both electrodes (both electrodes 31 and 32), and the gas flow rate was 1.5 L / min. No. In 16, gas was supplied from both electrodes (both electrodes 31 and 32), and the gas flow rate was 3.0 L / min.

  As shown in Table 5, No. 14 and No. In No. 15, the median diameter is No. No. 14 15 is smaller. By supplying gas from both electrodes 31, 32, the dispersion effect of the submerged plasma chamber 40 can be improved. No. 15 and No. When comparing No. 16, the median diameter is No. No. 15 16 is smaller. By doubling the gas supply amount, the dispersion effect of the submerged plasma chamber 40 can be further improved. Then, it was confirmed that the results obtained in the case of titanium oxide in Table 4 are not a phenomenon specific to titanium oxide. As described above, it is preferable for dispersion to supply gas from both electrodes and increase the supply amount.

(Example 5)
As Example 5, atomization was performed by changing the arrangement angle of the hollow electrodes 31 and 32. In this example, it was confirmed whether the dispersion effect changes depending on the arrangement angle of the hollow electrodes 31 and 32 used in the submerged plasma chamber 40, and the optimum dispersion condition of the submerged plasma chamber 40 was confirmed.

  In the fifth embodiment, No. 17 to No. The high-pressure jet treatment device 152 and the plasma generator 160 were used in all 22 samples. The processing conditions for in-liquid plasma and high-pressure injection are as follows: injection pressure 245 MPa, number of passes 30 times (sampling of the processed sample is performed every 10 passes, measurement is performed using each sampling liquid), pulse width 1.5 μs, The nozzle diameter of the chamber was 0.14 mm. The gas supplied to the gas supply means 180 was air. The components of air are nitrogen 78.08%, oxygen 20.95%, argon 0.93%, and carbon dioxide 0.03%. No. 17-No. The chamber 22 was an in-liquid plasma chamber 40. The test circuit is shown in FIG.

In the case of titanium oxide solution In Table 6, the titanium oxide solution is used as the raw material solution 10 (atomization material), and the particle size when the atomization treatment is performed by the submerged plasma chamber 40 while changing the arrangement of the electrodes 31 and 32. The distribution measurement result and the pH measurement result are shown. No. 17-No. Specifically, the titanium oxide solution of the raw material solution 10 used in 19 was prepared by suspending 6 g of a solute of titanium oxide P25 powder (manufactured by Degussa) and 594 g of ion-exchanged water as a solvent, a concentration of 1 wt%, and a treatment amount of 600 mL. The titanium oxide solution of was used. The distance between the electrodes was 1 mm. The measured values are the median diameter (nm) and pH change of titanium oxide before and after the treatment, and were measured by a dynamic scattering particle size distribution device (Zetasizer Nano ZS, Spectris Co., Ltd.). No. 17-No. In 19, gas was supplied from both electrodes (both electrodes 31 and 32), and the gas flow rate was 3.0 L / min. In the 0 pass, the median diameter is not stable because the particles settle down quickly, and the dispersion occurs between about 400 and 4000 nm.

  The electrodes 31, 32 are arranged in No. 17 to No. Changed at 19. No. 17, the electrode pairs 31 and 32 were obliquely arranged on the raw material IN side at an angle of 10 degrees (FIG. 12). That is, as shown in FIG. 12, with the direction perpendicular to the direction of the jet flow jetted from the high-pressure nozzle 41 being 0 °, the tips of the electrodes 31 and 32 are positioned on the upstream side of the jet flow (of the raw material solution 10 in the chamber 40). It was arranged with an inclination of 10 degrees toward the supply port). No. In FIG. 18, the electrode pairs 31 and 32 are arranged so as to face each other (FIG. 2). No. In FIG. 19, the electrode pairs 31 and 32 were obliquely arranged at an angle of 10 degrees on the raw material OUT side (FIG. 13). That is, as shown in FIG. 13, arranging the material OUT side at an angle of 10 degrees at an angle means that the direction perpendicular to the direction of the jet flow ejected from the high-pressure nozzle 41 is 0 degree, and the tip of the electrode 31. Was inclined 10 degrees toward the downstream side of the jet flow (in the direction of the outlet of the raw material solution 10 in the chamber 40).

  As shown in Table 6, no. 17-No. 19, the median diameter is No. 18 was the minimum. The electrodes 31 and 32 can be effectively dispersed by disposing them facing each other. No. The reason that No. 17 was not effective is that the gas ejection port faces the IN side, so that the injection of the raw material becomes a resistance of the gas injection, and It is considered that this is because the amount of bubbles between the electrodes 31 and 32 was smaller than that of No. 18 and the frequency of generation of in-liquid plasma decreased. In addition, No. The reason why 19 is not effective is that the gas jet is directed toward the OUT side, so that the injection of the raw material accelerates the injection of the gas, and the bubble exits before the bubbles cover the electrodes 31 and 32. It is considered that this is because the frequency of outflow to the plasma increased and the frequency of plasma generation in the liquid decreased.

In the case of zirconia solution In Table 7, the zirconia solution is used as the raw material solution 10 (atomization material), and the particle size distribution is measured when the atomization treatment is performed by the submerged plasma chamber 40 while changing the arrangement of the electrodes 31 and 32. The results and pH measurement results are shown. No. 20-No. Specifically, the titanium oxide solution of the raw material solution 10 used in No. 22 was prepared by suspending a solute of 6 g of titanium oxide P25 powder (manufactured by Degussa) and a solvent of 594 g of ion-exchanged water at a concentration of 1 wt% and a treatment amount of 600 mL. The titanium oxide solution of was used. The distance between the electrodes was 5 mm. The measured values are the median diameter (nm) and pH change of titanium oxide before and after the treatment, and were measured by a dynamic scattering particle size distribution device (Zetasizer Nano ZS, Spectris Co., Ltd.). No. 20-No. In No. 22, gas was supplied from both electrodes (both electrodes 31 and 32), and the gas flow rate was 3.0 L / min. In the 0 pass, the median diameter is not stable because the particles settle down quickly, and the dispersion occurs between about 400 and 4000 nm.

  The electrodes 31 and 32 are arranged in No. 20 to No. 20. Changed at 22. No. In No. 20, the electrode pairs 31 and 32 were obliquely arranged on the raw material IN side at an angle of 10 degrees (FIG. 12). No. 21, the electrode pairs 31 and 32 are arranged so as to face each other (FIG. 2). No. In No. 22, the electrode pairs 31 and 32 were obliquely arranged on the raw material OUT side at an angle of 10 degrees (FIG. 13).

  As shown in Table 7, No. 20-No. 22, the median diameter is No. 21 became the minimum. The electrodes 31 and 32 can be effectively dispersed by disposing them facing each other. No. 1 in which the electrodes were obliquely arranged using a zirconia solution was used. 20 and No. 20. The reason why No. 22 was not effective was that No. 22 in which the electrodes were obliquely arranged using titanium oxide was used. 17 and No. 17 It is considered that 19 was similar to the reason why it was not effective. As described above, it is preferable to dispose the electrodes facing each other for dispersion.

100 wet atomizer,
10 raw material solution,
20 dispersions,
1a particles,
30 plasma generation power supply,
31 (31a, 31b, 31c, 31d), 32 (32a, 32b, 32c, 32d) electrodes,
33 (33a, 33b, 33c), 34 (33a, 33b, 33c) interval adjusting means,
40 chambers,
41 high pressure nozzle,
52 containers,
80 pumps,
152 high pressure injection processing device,
160 liquid plasma generator,
180 gas supply means,
181 valve,
C1 cavitation bubbles,
D1 gas supply means bubble P1 plasma generation location in liquid,
Distance between S1 electrodes

Claims (9)

A high-pressure injection processing device for high-pressure injection from a high-pressure nozzle provided in a chamber and a submerged plasma generator are combined, and hollow electrodes of the submerged plasma generator are arranged to face each other in the chamber. Gas supply means for supplying gas into the chamber from the electrode of No. 2 is arranged, and the pressure of high pressure injection from the high pressure nozzle of the high pressure injection processing device is 100 to 245 MPa and the injection speed is 440 to 700 m / s. By injecting the raw material solution and exerting cavitation by the high-pressure injection on the plasma generation area, the gas is supplied by the gas supply means to pass through the hollow-shaped electrode, and to the opposite hollow-shaped electrode. After injecting the gas toward the hollow electrode, a pulse voltage is applied to the hollow electrode to generate a liquid plasma. A wet atomization method of that raw material,
Regarding the relation between the normalized standoff distance (normalized standoff distance: s / d) and the erosion amount of the electrode, the standoff distance s is defined as the standoff distance s (distance from the nozzle injection port to the processed sample) as the nozzle exit diameter d. Is a dimensionless amount at the nozzle outlet diameter d, and due to the increase in the standoff distance s, it is located at a position excluding two peaks near the nozzle where the erosion amount is the peak and the second peak on the downstream side. Wet particles of a raw material, characterized in that the hollow electrode is arranged, the hollow electrode is moved, or the hollow electrode pair is inclined at an angle to the raw material OUT side. Method. A high-pressure injection processing device for high-pressure injection from a high-pressure nozzle provided in a chamber and a submerged plasma generator are combined, and hollow electrodes of the submerged plasma generator are arranged to face each other in the chamber. Gas supply means for supplying gas into the chamber from the electrode of No. 2 is arranged, and the pressure of high pressure injection from the high pressure nozzle of the high pressure injection processing device is 100 to 245 MPa and the injection speed is 440 to 700 m / s. By injecting the raw material solution and exerting cavitation by the high-pressure injection on the plasma generation area, the gas is supplied by the gas supply means to pass through the hollow-shaped electrode, and to the opposite hollow-shaped electrode. After injecting the gas toward the hollow electrode, a pulse voltage is applied to the hollow electrode to generate a liquid plasma. A wet atomization method of that raw material,
Regarding the relation between the normalized standoff distance (normalized standoff distance: s / d) and the erosion amount of the electrode, the standoff distance s is defined as the standoff distance s (distance from the nozzle injection port to the processed sample) as the nozzle exit diameter d. Is a dimensionless amount at the nozzle outlet diameter d, and by increasing the standoff distance s, the erosion of the second peak of the two peaks of the first peak near the nozzle and the second peak on the downstream side Since many bubbles are generated at the second peak when it is caused by the generated cavitation, the hollow electrode is arranged at the position of the second peak or the hollow electrode is moved. Or, the hollow-shaped electrode pair is obliquely inclined to the raw material OUT side at an angle, and wet atomization of the raw material is performed. Law. The hollow-shaped electrode is filled with the raw material solution in the chamber, and a pump for refluxing the solution is provided, and high-pressure injection of the high-pressure nozzle of the high-pressure injection processing apparatus is performed a plurality of times to perform the plasma treatment in the liquid. The method for wet atomizing a raw material according to claim 1 or 2 , wherein the method is repeated. A high-pressure injection processing device for high-pressure injection from a high-pressure nozzle provided in a chamber and a submerged plasma generator are combined, and hollow electrodes of the submerged plasma generator are arranged to face each other in the chamber. A gas supply means for supplying gas from the electrode of the above into the chamber,
The raw material solution is jetted from the high-pressure nozzle of the high-pressure jet processing device to cause cavitation by the high-pressure jet in the plasma generation area, and the gas is supplied by the gas supply means to pass through the hollow electrode. , Injecting the gas toward the opposing hollow-shaped electrodes, and then applying a pulse voltage to the hollow-shaped electrodes to generate in-liquid plasma,
The hollow-shaped electrode is filled with the raw material solution in the chamber, and a pump for refluxing the solution is provided, and high-pressure injection of the high-pressure nozzle of the high-pressure injection processing apparatus is performed a plurality of times to perform the plasma treatment in the liquid. A wet atomizer for a raw material characterized by repeating. While injecting the raw material solution from the high-pressure nozzle of the high-pressure injection processing device at a high-pressure injection pressure of 100 to 245 MPa and an injection speed of 440 to 700 m / s,
Regarding the relation between the normalized standoff distance (normalized standoff distance: s / d) and the erosion amount of the electrode, the standoff distance s is defined as the standoff distance s (distance from the nozzle injection port to the processed sample) as the nozzle exit diameter d. Is a dimensionless amount at the nozzle outlet diameter d, and due to the increase in the standoff distance s, it is located at a position excluding two peaks near the nozzle where the erosion amount is the peak and the second peak on the downstream side. 5. The hollow-shaped electrode is arranged, the hollow-shaped electrode is moved, or the hollow-shaped electrode pair is inclined at an angle to the raw material OUT side. Wet atomizer for raw materials. While injecting the raw material solution from the high-pressure nozzle of the high-pressure injection processing device at a high-pressure injection pressure of 100 to 245 MPa and an injection speed of 440 to 700 m / s,
Regarding the relation between the normalized standoff distance (normalized standoff distance: s / d) and the erosion amount of the electrode, the standoff distance s is defined as the standoff distance s (distance from the nozzle injection port to the processed sample) as the nozzle exit diameter d. Is a dimensionless amount at the nozzle outlet diameter d, and by increasing the standoff distance s, the erosion of the second peak of the two peaks of the first peak near the nozzle and the second peak on the downstream side Since many bubbles are generated at the second peak when it is caused by the generated cavitation, the hollow electrode is arranged at the position of the second peak or the hollow electrode is moved. 5. The raw material according to claim 4, wherein the hollow electrode pair is inclined at an angle to the raw material OUT side. Wet atomization device.   When arranging the hollow-shaped electrode at the second peak, whether the electrode is titanium, stainless steel, or tungsten as an erosion resistant material, or cemented carbide, zirconia, or alumina as an erosion prevention member. And / or the erosion resistant shape is a columnar shape or a polygonal shape, and the wet atomization apparatus for raw materials according to claim 6.   The control mechanism capable of moving the hollow electrode along the direction of the jet flow of the raw material solution (direction perpendicular to the axis A of the electrode pair) is provided. 7. The wet atomization device for raw materials according to any one of 6 above.   The injection direction of the high-pressure nozzle is adjusted such that an angle (inclination angle α) between the horizontal plane L and the injection direction M is in the range of 5 to 20 degrees, more preferably 10 to 15 degrees. 7. A wet atomization apparatus for raw materials according to any one of 4 to 6.