KR100462073B1 - An ultrasonic spray pyrolysis apparatus for the production of ultrafine particles - Google Patents

Abstract

The present invention relates to an ultrasonic spray pyrolysis apparatus capable of synthesizing a large amount of fine powder, a droplet generator for generating droplets from a reaction solution, a droplet spray container, a reactor for drying and pyrolyzing the sprayed droplets to generate particles, And a collector for collecting the generated particles, wherein the droplet generator comprises an ultrasonic vibrator divided into a plurality of groups, wherein the reactor includes a plurality of reaction tubes therein; The ultrasonic spray pyrolysis apparatus according to the present invention, in which the spray container and the reaction tube are provided in the number corresponding to each of the ultrasonic vibrator groups, is easy to be mass-capable and the optimum operating conditions can be easily grasped, and the optimal operation at the laboratory scale is possible. From the conditions, fine particles having excellent characteristics can be produced in large quantities.

Description

Ultrasonic Spray Pyrolysis Apparatus for Fine Powder Synthesis {AN ULTRASONIC SPRAY PYROLYSIS APPARATUS FOR THE PRODUCTION OF ULTRAFINE PARTICLES}

The present invention relates to an ultrasonic spray pyrolysis apparatus capable of synthesizing a large amount of fine powder, and more specifically, a droplet generator including an ultrasonic vibrator divided into a plurality of groups, and sprays provided with the number of ultrasonic vibrator groups in the droplet generator. An ultrasonic spray pyrolysis device comprising a vessel and a reaction tube.

The spray pyrolysis process is a typical gas phase synthesis method for producing spherical fine particles. The spray pyrolysis apparatus for using the spray pyrolysis process is generally a droplet generator, a reactor for drying / pyrolysis of droplets, and a part for collecting particles. It consists of. In the production of fine particles using the spray pyrolysis process, since the amount of particles generated is proportional to the amount of droplets generated, a large amount of droplet generating apparatus is essential for mass synthesis of the fine particles.

Laboratory-scale spray pyrolysis apparatus including less than 10 oscillators generating droplets can efficiently utilize droplets regardless of the arrangement of the oscillators, but when the number of oscillating droplets is increased to tens or hundreds, And the distribution of the resulting droplets greatly affects the efficiency of the spray pyrolysis apparatus, and also, depending on how the injected droplets are injected into the reactor, optimal operating conditions and properties of the obtained fine particles vary. That is, in the production of fine particles by spray pyrolysis, important variables affecting the physical properties of the produced particles include concentration of solute, flow rate of carrier gas, manufacturing temperature and residence time. In general, the concentration of the reactants affects the size of the particles formed, the flow rate of the carrier gas affects the residence time and drying speed of the droplets in the reactor, thus affecting the shape of the particles. Affects crystallinity and drying rate.

Conventional mass particle production apparatus using the spray pyrolysis method is to use the process of drying and pyrolyzing a large amount of droplets formed by attaching a large amount of droplet generating device to a large diameter reactor using a carrier gas of a large flow rate. to be. However, as the size of the reactor increases, the temperature gradient in the reactor increases, and the amount of carrier gas increases, thereby changing the drying rate and residence time of the particles, which may change the conditions for producing optimized particles on a laboratory scale. Means. Also, when the droplets formed in the bulk droplet generator are transferred to one large diameter reactor, the temperature difference between the reactor wall and the center in the reactor is severe and the collisions between the droplets are severe, thereby reducing the efficiency of the droplet generator. It adversely affects the shape and crystallinity of the final obtained particles.

In addition, the type and combination of the reactor should be different depending on the method of generating the droplets. In the case of the size of the reactor, the most preferable case is that there is no temperature gradient in the reactor in which the droplets are transported, and the residence time is sufficient for the droplets to be dried / pyrolyzed. In order to reduce the diameter of the reaction tube, it is advantageous. However, in order to properly handle the droplets formed in the bulk droplet generator, the flow rate of the carrier gas must be increased. When the diameter of the reaction tube is small, the length of the reaction tube is increased to give sufficient residence time for drying / pyrolysis of the droplets. There is a problem of spatial limitations in the design.

Therefore, the present inventors have developed a large-scale spray pyrolysis system capable of maintaining the conditions for producing optimized particles in a laboratory scale apparatus even when the scale of the apparatus becomes large.

Accordingly, an object of the present invention is to provide a droplet generator including a plurality of ultrasonic vibrators divided into a plurality of groups and the resulting droplets are divided into a plurality of spray containers corresponding to each group and then supplied and dried and pyrolyzed. By using the same number of reaction tubes as the number of groups to be made, it is possible to provide an improved spray pyrolysis apparatus that can be mass-capable and generate a large amount of fine particles under optimum conditions.

1 is a schematic diagram of an ultrasonic spray pyrolysis apparatus according to an embodiment of the present invention;

2 is a schematic diagram of an ultrasonic nebulizer (droplet generator) having 36 vibrators used in the ultrasonic nebulization pyrolysis apparatus according to one embodiment of the present invention;

3 is a schematic diagram of an ultrasonic nebulizer (droplet generator) having 100 vibrators used in the ultrasonic nebulization pyrolysis apparatus according to another embodiment of the present invention;

Figure 4 is a schematic diagram of a spray container for mass droplet generation used in the ultrasonic spray pyrolysis apparatus according to an embodiment of the present invention;

5 is a schematic diagram of an electric furnace having several reaction tubes used in an ultrasonic spray pyrolysis apparatus according to an embodiment of the present invention;

6 is a schematic view of a particle collecting device used in the ultrasonic spray pyrolysis device according to an embodiment of the present invention;

7 is a scanning electron micrograph of the spherical BaMgAl ₁₀ O ₁₇ : Eu blue phosphor particles prepared in Example 1;

8 is a photoluminescence spectrum of the spherical BaMgAl ₁₀ O ₁₇ : Eu blue phosphor particles prepared in Example 1 and a commercial product;

9 is a scanning electron micrograph of the Ni particles prepared in Example 2. FIG.

Description of the main parts of the drawing

1: droplet generator 10: polymer membrane

2: electric furnace 11: distribution means

3: collector 12: carrier gas inlet

4: Spray container 13: Outlet of the spray container

5: reaction tube 14: solution inlet

6: hood 15: filter

7: vibrator 16: vacuum pump

8: cooling water inlet

9: cooling water outlet

In order to achieve the above object, in the present invention, a droplet generator for generating droplets from the reaction solution, a droplet spray container, a reactor for drying and pyrolyzing the sprayed droplets to produce particles, and a collector for collecting the generated particles In the ultrasonic spray pyrolysis apparatus comprising, the droplet generator comprises an ultrasonic vibrator divided into a plurality of groups, the reactor includes a plurality of reaction tubes therein, the spray vessel and the reaction tube is the ultrasonic vibrator, respectively Provided is an ultrasonic spray pyrolysis device, characterized in that provided by the number of groups.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

1 is a schematic diagram of a spray pyrolysis apparatus for synthesizing bulk particles according to an embodiment of the present invention. The apparatus is largely divided into three parts: parts (1, 4) for generating and effectively distributing droplets in bulk, parts (2, 5) for drying and pyrolyzing the droplets (3, 6) It consists of.

In the apparatus shown in FIG. 1, a large amount of droplets generated using the droplet generator 1 is supplied from the spray container 4 to the plurality of reaction tubes 5 located in the electric furnace 2 by the carrier gas. And dried, pyrolyzed and calcined to form fine particles, which are collected in a hood 6 connected to the end of the reaction tube 5 and then collected by the collector 3, and the collector 3 is transported with a carrier gas. A vacuum pump 16 for smoothly discharging may be connected.

Figures 2 and 3 are plan views of an ultrasonic atomizer (drop generator) 1 which can be used in the spray pyrolysis apparatus according to the invention, Figure 2 comprising four zones with nine vibrators in one zone, i.e. 36 3 shows a droplet generator having two vibrators, and FIG. 3 is a variation of the droplet generator illustrated in FIG. 2, which includes 25 vibrators in one zone, that is, includes 100 vibrators divided into four zones. The droplet generator is shown.

That is, the droplet generator 1 used in the apparatus of the present invention may be a plurality of, for example, four (FIG. 2) using a plurality of, for example, 9 to 100 vibrators 7 as a group. ㉱ to ㉱ zone of) to 50 groups. In addition, the droplet generator 1 may be provided with a cooling water inlet 8 and an outlet 9 for supplying cooling water to cool the heat generated when the vibrators 7 operate. In the droplet generator shown in Figs. 2 and 3, to distinguish each group, each group uses a respective container (for example, an acrylic plate container), and spray solution is applied to each container. It will be contained.

4 is a schematic view of the spray container 4 installed connected to the ultrasonic spray device (drop generator) 1 of the present invention. The spray container may be made of an acrylic plate, it is designed to optimize the spraying of the solution, and to effectively supply a large amount of droplets formed into the electric furnace.

The spray container 4 is positioned above the droplet generator 1 with an ultrasonic vibrator 7 and a thin polymer membrane 10 capable of separating the liquid to be sprayed therebetween, and continuously moving the generated droplets. A carrier gas inlet 12 for injecting a carrier gas for dispensing, a dispensing means 11 for efficiently distributing the carrier gas in the container, and a solution inlet 14 for continuously supplying the reaction solution, and As shown, it serves to efficiently droplet and atomize the solution to be injected. At this time, the distribution means 11 is in the form of a blade (blade), it is preferably installed at an angle of 45 ° with respect to the vertical inner wall of the spray container (4), in order to minimize the collision between the droplets generated in the container It is preferable that the outlet portion 13 of the spray container is also inclined at an angle of 45 °. The polymer film 10 may be made of polyacetal, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or the like.

The apparatus of the present invention comprises a reactor, for example an electric furnace 2, for effectively drying and pyrolyzing large quantities of droplets. The electric furnace 2 is composed of the same number of reaction tubes 5 as the number of vibrator groups included in the droplet generator 1, and each reaction tube 5 is designed so that the temperature therein can be controlled. . For example, an electric furnace designed for a droplet generator with four groups of vibrators as shown in FIG. 2 consists of four reaction tubes 5 as shown in FIG. 5. The reaction tube 5 may be a quartz tube or an alumina tube.

According to the present invention, the size of each reaction tube 5 has a minimum size to match the size of one group of vibrators, that is, the diameter of the reaction tube 5 may include ultrasonic vibrators included in one group. It is desirable to be designed to be. Accordingly, even in the case of a large-capacity device including a large droplet generator, it is possible to have the same effect as supplying the droplets generated after spraying the droplets with one spraying device to an electric furnace including one reaction tube therein. In addition, a carrier gas injected into each vibrator group may also be supplied at a flow rate corresponding to the size of one vibrator group.

The droplets respectively fed to the reaction tube 5 typically form particles of several microns as they are dried and pyrolyzed for several seconds at a temperature of 200 to 1500 ° C. The particles formed in the reactor, as shown in FIG. 6, are collected in the hood 6 portion and then collected in the collector 3 and filtered through the filter 15 in the collector. A vacuum pump 16 for smoothly discharging the carrier gas supplied for droplet movement may be connected to the rear of the collector, and the filter 15 may generally be a bag filter, an electrostatic precipitator, a cyclone, or the like. Can be.

Can be prepared in large quantities the particle having a micron-sized or sub-micron size by using a large particle manufacturing apparatus of the present invention, as a specific example, using the production apparatus of the present invention, ZnO, Mn ₃ O _4, TiO _2, SiO Monocomponent oxides selected from ₂ , CuO, PbO and NiO; Metal particles selected from Ag, Ni, Cu, Pd and Au; Multicomponent particles selected from YBa ₂ Cu ₃ O ₇ , BaTiO ₃ , SrTiO ₃ , BST and PZT; Y ₂ O ₃ : Eu, Gd ₂ O ₃ : Eu, (YGd) BO ₃ : Eu, Zn ₂ SiO ₄ : Mn, BaMgAl ₁₀ O ₁₇ : Mn, Sr ₅ (PO ₄ ) ₃ Cl: Eu, (Ba, Oxide based phosphor selected from Sr) SiO ₄ : Eu, Y ₂ SiO ₅ : Tb, YAG: Ce, SrTiO ₃ : Pr, Al and BaAl ₁₂ O ₁₉ : Mn; Alternatively, sulfide-based particles selected from ZnS and CdS may be manufactured in large quantities.

Spray pyrolysis process using the ultrasonic spray pyrolysis apparatus according to the present invention through the process of co-spraying, split feeding and drying / pyrolysis process of the precursor spray solution, the conditions optimized in the lab-scale low-volume particulate generator as it is A large amount of microparticles | fine-particles which do not fall even if it uses can be manufactured. As an embodiment, using the operating conditions of the spray device having nine vibrators, which are conditions that can be experimentally easy to operate and produce fine particles having excellent characteristics, the fine particles of high quality with a large-capacity spray device having 36 vibrators It can be manufactured in large quantities, and thus, the size of the droplet generator can be expanded and applied to a large-scale droplet generator having 100 to 1000 vibrators.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example 1 Preparation of BaMgAl ₁₀ O ₁₇ : Eu Phosphor Particles

As a starting material, a precursor spray solution was prepared to have the same composition as the title compound using 0.09M of barium nitrate solution, 0.1M of magnesium nitrate solution, 0.1M of europium nitrate solution, and 1M of alumina polymer solution. The spray solution thus prepared was placed in an ultrasonic spray apparatus shown in FIG. 1 and generated as droplets of about 10 microns, and the resulting droplets were dried and pyrolyzed at a reactor temperature of 900 ° C. to obtain blue phosphor particles having a title composition. , The electron micrograph of this particle is shown in FIG. As shown in Figure 7, it can be seen that the phosphor prepared by using the spray pyrolysis apparatus according to the present invention is spherical and has a size of several microns.

The photoluminescence spectra of the obtained phosphor particles and commercially available BaMgAl ₁₀ O ₁₇ : Eu phosphor (manufactured by KASEI, Japan) are shown in FIG. 8. As shown in Fig. 8, the phosphor produced by the apparatus of the present invention exhibits better luminescence properties.

Example 2: Preparation of Spherical Ni Metal Powder of Micro Size

As a raw material, a 0.5 M spray solution prepared by dissolving a nickel compound such as NiCl ₂ , NiCO ₃ or Ni (CH ₃ COO) ₂ in water is used, and 5% H ₂ / N ₂ mixed gas is used as a carrier gas. Except for using, Ni metal powder was obtained by the same procedure as in Example 1, and an electron micrograph thereof is shown in FIG. 9. As shown in Figure 9, it can be seen that the Ni metal powder prepared using the spray pyrolysis apparatus according to the present invention is spherical in the micron size.

A process of generating a large amount of droplets from the reaction solution by using a plurality of ultrasonic vibrators divided into a plurality of groups, splitting and supplying these droplets to a plurality of reactors corresponding to each group, and then drying and pyrolyzing to collect powder The large-capacity spray pyrolysis particle generating device according to the present invention can easily find the optimum operating conditions from the optimized conditions in the laboratory-scale low-capacity particle generating device, and can generate a large amount of fine particles that do not degrade in quality even when large-capacity is increased. .

Claims (9)

In the ultrasonic spray pyrolysis apparatus comprising a droplet generator for generating droplets from the reaction solution, a droplet spray container, a reactor for drying and pyrolyzing the sprayed droplets to produce particles, and a collector for collecting the generated particles; The droplet generator includes an ultrasonic vibrator divided into a plurality of groups, the reactor includes a plurality of reaction tubes therein, and the spray container and the reaction tube are each provided with the number of ultrasonic vibrator groups. Ultrasonic spray pyrolysis device. The method of claim 1, Apparatus characterized in that each droplet spray container is connected to the upper portion of each group of ultrasonic vibrators in the droplet generator, each reaction tube is connected to the upper portion of each droplet spray container is installed. The method of claim 2, The droplet spray container includes a solution inlet for continuously supplying a reaction solution, a carrier gas inlet for injecting a carrier gas for continuously moving the generated droplets, and a distribution means for efficiently dispensing the injected carrier gas in the container. And the distributing means is a blade installed at an angle of 45 ° with respect to the vertical inner wall of the spray container. The method of claim 3, And a polymer membrane is formed at the connection portion of the droplet generator and the droplet spray container to separate the ultrasonic vibrator and the reaction solution. The method of claim 2, Wherein the diameter of each reaction tube is designed to have a minimum size that can include ultrasonic vibrators included in the corresponding group of ultrasonic vibrators. The method of claim 1, Wherein the droplet generator comprises 4 to 50 ultrasonic vibrator groups and one ultrasonic vibrator group comprises 9 to 100 vibrators. The method of claim 1, Behind the collector, characterized in that the vacuum pump is connected to be installed so as to smoothly discharge the carrier gas supplied for droplet movement. Micron-sized spherical microparticles produced using the device of claim 1. The method of claim 8, Particles are monocomponent oxides selected from ZnO, Mn ₃ O ₄ , TiO ₂ , SiO ₂ , CuO, PbO, and NiO; Metal particles selected from Ag, Ni, Cu, Pd and Au; Multicomponent particles selected from YBa ₂ Cu ₃ O ₇ , BaTiO ₃ , SrTiO ₃ , BST and PZT; Y ₂ O ₃ : Eu, Gd ₂ O ₃ : Eu, (YGd) BO ₃ : Eu, Zn ₂ SiO ₄ : Mn, BaMgAl ₁₀ O ₁₇ : Mn, Sr ₅ (PO ₄ ) ₃ Cl: Eu, (Ba, Oxide based phosphor selected from Sr) SiO ₄ : Eu, Y ₂ SiO ₅ : Tb, YAG: Ce, SrTiO ₃ : Pr, Al and BaAl ₁₂ O ₁₉ : Mn; Or a sulfide-based particle selected from ZnS and CdS.