An apparatus and method for preparing ultrafine powder

Abstract

This invention relates to the field of rare earth preparation technology, and discloses an apparatus and method for preparing ultrafine powders. The apparatus includes a containment chamber, a mixing chamber, an atomizing component, an incubation chamber, and a driving component. The mixing chamber is located within the containment chamber, and its side wall has multiple first through holes. The atomizing component is located within the mixing chamber, and each atomizing component includes two atomizing nozzles. The outlets of the two atomizing nozzles are arranged vertically opposite each other, and the inlet of each atomizing nozzle is used to inject the reaction liquid. The incubation chamber is installed within the containment chamber and is located below the mixing chamber. The side wall of the incubation chamber has multiple second through holes, and the bottom of the incubation chamber has a water inlet. The driving component includes a rotating shaft, which is vertically arranged and extends downward into the containment chamber, for driving the mixing chamber and the incubation chamber to rotate horizontally. This invention solves the problem that the final product obtained by the traditional precipitation method in the prior art has a large particle size and a wide particle size distribution range.

Description

Technical Field

[0001] This invention relates to the field of rare earth preparation technology, and in particular to an apparatus and method for preparing ultrafine powders. Background Technology

[0002] Currently, ultrafine highly dispersed nano-cerium carbonate, as a rare earth functional material, has advantages such as small particle size, particle dispersion, and narrow particle size distribution range, and has been widely used in multiple technical fields such as automobile exhaust purification, precision polishing, new energy batteries, and biomedicine.

[0003] Existing technology uses a precipitation method to prepare ultrafine, highly dispersed nano-cerium carbonate. This involves first preparing a soluble metal salt into a reaction solution, then slowly adding a precipitant to the reaction solution. The precipitant reacts chemically with the reaction solution to form a precipitate. After the reaction has been going on for a certain period of time, the precipitate is removed and repeatedly washed with deionized water or an organic solvent to remove impurity ions. Finally, the precipitate is dried at a set temperature to obtain the final target powder material.

[0004] However, in the above preparation process, after the precipitant is added to the reaction solution, the precipitant cannot diffuse rapidly, resulting in a high concentration of precipitant in local areas of the reaction solution. The high concentration of precipitant in these local areas reacts violently with the reaction solution to generate a large number of fine crystal nuclei. These fine crystal nuclei collide and aggregate in the reaction solution, forming agglomerated particles of various sizes. This results in a large particle size and a wide particle size distribution range in the final product, which is difficult to meet the requirements of ultrafine highly dispersed nano-cerium carbonate for small particle size and narrow particle size distribution range. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the final product obtained by the traditional precipitation method has a large particle size and a wide particle size distribution range, which is difficult to meet the requirements of ultrafine highly dispersed nano-cerium carbonate for small particle size and narrow particle size distribution range.

[0006] To address the aforementioned technical problems, the present invention provides an apparatus for preparing ultrafine powders, comprising: Reception room; The mixing chamber is located inside the containment chamber, and multiple first through holes are provided on the side wall of the mixing chamber; Atomizing components are located in the mixing chamber. There is at least one atomizing component. Each atomizing component includes two atomizing nozzles. The outlets of the two atomizing nozzles are arranged opposite each other, and the inlet of each atomizing nozzle is used to inject the reaction liquid. The incubation chamber is installed inside the containment chamber and is located below the mixing chamber; The incubation chamber has multiple second through holes on its side walls and a water inlet at its bottom. The drive assembly includes a rotating shaft, which is vertically positioned and extends downward into the housing chamber. Both the mixing chamber and the hatching chamber are mounted on the rotating shaft, which is used to drive the mixing chamber and the hatching chamber to rotate horizontally.

[0007] Preferably, the incubation chamber includes a first cylinder, a plurality of first openings are provided on the side wall of the first cylinder, a first screen is installed at the first opening, the mesh of the first screen forms a second through hole, the water inlet is located at the bottom of the first cylinder, and the rotating shaft is connected to the first cylinder.

[0008] Preferably, the incubation chamber further includes a second cylinder, the side wall of which is provided with a plurality of second openings, and a second screen is installed at each second opening; The bottom of the second cylinder is provided with a mounting hole that extends upwards through the top of the second cylinder. The first cylinder is inserted and fixed in the mounting hole, and the first opening is located inside the second cylinder.

[0009] Preferably, the second cylinder includes a base, a chamber, and a top cover stacked sequentially from bottom to top, with a mounting hole on the base and extending upward through the top cover, and a second opening on the side wall of the chamber.

[0010] Preferably, the first cylinder is inserted into the mounting hole, a stop plate is fixedly installed at the bottom of the first cylinder, the stop plate stops at the bottom surface of the base, the top of the first cylinder extends to the outside of the top cover, a limiting member is installed at the top of the first cylinder, the limiting member and the stop plate are used to position the base, the cylinder and the top cover, and the rotating shaft is connected to the limiting member.

[0011] Preferably, the incubation chamber further includes multiple partition plates disposed between the first cylinder and the chamber. The multiple partition plates are arranged at intervals along the circumference of the first cylinder to divide the space between the first cylinder and the chamber into multiple chambers. Each chamber is used to place packing material, and each partition plate is fixed on the base.

[0012] Preferably, the drive assembly further includes a drive motor connected to the rotating shaft; The drive motor is mounted on the top of the rotating shaft, which extends downward through the top of the containment chamber and the mixing chamber. The containment chamber is rotatably connected to the rotating shaft, the mixing chamber is fixedly connected to the rotating shaft, and the bottom of the rotating shaft is fixedly connected to the incubation chamber.

[0013] Preferably, the apparatus for preparing ultrafine powder further includes a feed pipe for conveying the reaction liquid; The top of the mixing chamber is provided with a first perforation, and the rotating shaft passes through the top of the receiving chamber, the first perforation and the bottom of the mixing chamber, and the bottom of the mixing chamber is fixedly connected to the rotating shaft; The feed pipe passes through the receiving chamber and the first perforation, and is connected to the inlet of the atomizing nozzle.

[0014] Preferably, the feed pipe includes a first rigid pipe and a second rigid pipe; The first rigid tube extends downward and passes through the top of the receiving chamber and the first perforation in sequence. The first rigid tube is fixedly connected to the top of the receiving chamber, and the lower end of the first rigid tube is fixedly connected to the atomizing nozzle located above in the atomizing assembly. The second rigid tube extends downward through the top of the receiving chamber and the first perforation. The second rigid tube is fixedly connected to the top of the receiving chamber. The lower end of the second rigid tube extends downward to the bottom of the atomizing assembly and then bends upward. The lower end of the second rigid tube is fixedly connected to the atomizing nozzle located at the bottom of the atomizing assembly.

[0015] This invention provides a method for preparing ultrafine powder, using the aforementioned apparatus for preparing ultrafine powder, and includes the following steps: S1. The reaction liquid is conveyed to the atomizing component to atomize the reaction liquid, and the atomized reaction liquid is horizontally sprayed onto the side wall of the mixing chamber after being impacted from above and below to form a mixed solution. S2. Drive the mixing chamber to rotate to shear the mixed solution and discharge the sheared mixed solution from the first through hole into the mixing chamber; S3, The mixed solution accumulates at the bottom of the containment chamber; S4. Drive the incubation chamber to rotate so that the mixed solution enters the incubation chamber from the inlet and discharges the mixed solution in the incubation chamber from the second through hole. S5. Repeat step S4 until the preset time is reached, then collect the mixed solution and filter and clean the collected mixed solution.

[0016] Compared with the prior art, the apparatus and method for preparing ultrafine powder of the present invention have the following advantages: The present invention discloses an apparatus and method for preparing ultrafine powder. By using at least one set of atomizing nozzles arranged vertically opposite each other, two streams of reaction liquid are atomized and collide at high speed, generating a strong turbulence effect and instantaneous high pressure. This allows the reaction liquid to complete efficient mixing and energy transfer in a very short time, achieving uniform mixing of the reactants and creating conditions for large-scale and uniform nucleation. This avoids the problem of coarse particles caused by excessively high local concentrations of the reaction liquid.

[0017] Subsequently, the driving component drives the mixing chamber, which has a first through hole on its side wall, to rotate horizontally. The high-speed rotating mixing chamber wall shears the mixed solution at high speed, further enhancing the collision, breakage, and dispersion of substances in the reaction solution. This not only breaks up the initially formed crystal nuclei or micro-aggregates, inhibiting their premature agglomeration and growth, but also further improves the microscopic mixing uniformity of the reactants, effectively increasing the nucleation driving force and nucleation rate. This significantly shortens the nucleation induction period and effectively avoids problems such as uneven nucleation, secondary nucleation, or abnormal grain growth that may be caused by excessively long nucleation time, laying a solid foundation for obtaining fine and uniform initial crystal nuclei.

[0018] Under the centrifugal force of the mixing chamber, the mixed solution, sheared by the mixing chamber, flows out through the first through-hole. Finally, the mixed solution flows to the bottom of the receiving chamber. The driving component drives the incubation chamber to rotate, creating a negative pressure space inside the high-speed rotating incubation chamber. The mixed solution at the bottom of the receiving chamber enters the incubation chamber through the inlet at the bottom of the incubation chamber. Under the centrifugal force of the incubation chamber, the mixed solution flows out through the second through-hole on the incubation chamber wall. At the same time as flowing out, the high-speed rotating incubation chamber wall performs secondary shearing on the mixed solution. The mixed solution flowing out of the incubation chamber re-enters the incubation chamber through the inlet, thus achieving cyclic shearing of the mixed solution. Through the cyclic shearing of the incubation chamber, austenitic ripening is suppressed, which can accelerate the uniform mass transfer of micro-nucleation, improve mass transfer and reaction efficiency, avoid abnormal particle growth, and the grown particles will also be sheared and dispersed again, thereby producing ultrafine powders with small particle size and narrow distribution range.

[0019] Compared to traditional precipitation methods, this invention does not rely on dispersants and solves the problem of large particle size and wide particle size distribution of the final product obtained by traditional precipitation methods through purely physical means. Ultimately, it can stably prepare ultrafine highly dispersed nanoparticles with small particle size and narrow distribution, which meets the stringent requirements of high-end application fields. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 This is a three-dimensional diagram of the incubation chamber according to an embodiment of the present invention; Figure 3 This is an exploded view of the incubation chamber according to an embodiment of the present invention; Figure 4 This is a cross-sectional view of the incubation chamber according to an embodiment of the present invention; Figure 5 This is a cross-sectional view of the mixing chamber according to an embodiment of the present invention; Figure 6 This is a three-dimensional view of the mixing chamber according to an embodiment of the present invention; Figure 7 This is a diagram showing the supply of reaction raw materials according to an embodiment of the present invention; Figure 8 This is the particle size distribution-bulk density curve of ultrafine, highly dispersed cerium carbonate nanoparticles with D50=58nm according to an embodiment of the present invention. Figure 9 This is the particle size distribution-bulk density curve of ultrafine, highly dispersed cerium carbonate nanoparticles with D50=106nm according to an embodiment of the present invention.

[0021] In the diagram, 1 is the containment chamber; 11 is the outlet; 12 is the heat exchange jacket; 2 is the mixing chamber; 21 is the third opening; 22 is the third screen; 23 is the connecting sleeve; 2a is the first perforation; 2b is the second perforation; 3 is the atomizing assembly; 31 is the atomizing nozzle; 4 is the incubation chamber; 41 is the first cylinder; 41a is the first opening; 41b is the first screen; 41c is the water inlet; 411 is the stop plate; 412 is the limiting component; 412a is the mounting screw hole; 413 is the mounting thread; 42 is the second cylinder; 42a is the second opening; 42b is the second screen; 42c is the mounting hole; 421 is the base; 421a is the partition plate; 422 is the chamber; 423 is the top cover. 5. Drive assembly; 51. Rotating shaft; 52. Drive motor; 6. Feed pipe; 61. First rigid pipe; 62. Second rigid pipe; 7. Raw material tank; 8. Collection tank; 9. Adjustment tank; 10. Preparation device. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0023] In the description of this invention, it should be understood that the terms "upper", "lower", "vertical", "horizontal", "bottom", "inner", "outer" and other terms used in this invention to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0024] It should be understood that the terms "first," "second," etc., are used in this invention to describe various types of information, but these terms are not limited to them; they are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, "first" information may also be referred to as "second" information, and similarly, "second" information may also be referred to as "first" information.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] like Figures 1 to 6As shown, a preferred embodiment of the present invention provides an apparatus for preparing ultrafine powder, comprising a receiving chamber 1, a mixing chamber 2, an atomizing component 3, an incubation chamber 4, and a driving component 5. The receiving chamber 1 has an outlet 11 at its bottom. The mixing chamber 2 is located within the receiving chamber 1, and its sidewalls have multiple first through holes. The atomizing component 3 is located within the mixing chamber 2, and there is at least one atomizing component 3. Each atomizing component 3 includes two atomizing nozzles 31, with their outlets arranged vertically opposite each other. The inlet of each atomizing nozzle 31 is used to inject a reaction liquid. The incubation chamber 4 is installed within the receiving chamber 1 and is located below the mixing chamber 2. The sidewalls of the incubation chamber 4 have multiple second through holes, and its bottom has a water inlet 41c. The driving component 5 includes a rotating shaft 51, which is vertically arranged and extends downwards into the receiving chamber 1. Both the mixing chamber 2 and the incubation chamber 4 are mounted on the rotating shaft 51, which drives the mixing chamber 2 and the incubation chamber 4 to rotate horizontally.

[0027] By using at least one set of atomizing nozzles 31 arranged vertically opposite each other, the two reaction liquids are atomized and collide at high speed, generating a strong turbulence effect and instantaneous high pressure. This allows the reaction liquids to complete efficient mixing and energy transfer in a very short time, achieving uniform mixing of the reactants and creating conditions for large-scale, uniform nucleation. This avoids the problem of coarse particles caused by excessively high local concentrations of the reaction liquids.

[0028] Subsequently, the driving component 5 drives the mixing chamber 2, which has a first through hole on its side wall, to rotate horizontally. The high-speed rotating mixing chamber 2 shears the mixed solution at high speed, further enhancing the collision, breakage and dispersion of substances in the reaction liquid. This not only breaks up the initially formed crystal nuclei or micro-aggregates and inhibits their premature agglomeration and growth, but also further improves the microscopic mixing uniformity of the reactants, effectively increasing the nucleation driving force and nucleation rate. This significantly shortens the nucleation induction period and effectively avoids problems such as uneven nucleation, secondary nucleation or abnormal grain growth that may be caused by excessively long nucleation time, laying a solid foundation for obtaining fine and uniform initial crystal nuclei.

[0029] Under the centrifugal force of the mixing chamber 2, the mixed solution, sheared by the mixing chamber 2, flows outward from the first through-hole. Finally, the mixed solution flows to the bottom of the receiving chamber 1. The driving component 5 drives the incubation chamber 4 to rotate. A negative pressure space is formed inside the high-speed rotating incubation chamber 4. The mixed solution at the bottom of the receiving chamber 1 enters the incubation chamber 4 through the water inlet 41c at the bottom of the incubation chamber 4. Under the centrifugal force of the incubation chamber 4, the mixed solution flows out from the second through-hole on the chamber wall of the incubation chamber 4. At the same time as it flows out, the high-speed rotating chamber wall of the incubation chamber 4 performs secondary shearing on the mixed solution. The mixed solution flowing out of the incubation chamber 4 re-enters the incubation chamber 4 through the water inlet 41c, thus achieving cyclic shearing of the mixed solution. Through the cyclic shearing of the incubation chamber 4, austenitic ripening is suppressed, which can accelerate the uniform mass transfer of micro-nucleation, improve the mass transfer and reaction efficiency, avoid abnormal particle growth, and the grown particles will also be sheared and dispersed again, thereby preparing ultrafine powder with small particle size and narrow distribution range.

[0030] Compared to traditional precipitation methods, the embodiments of the present invention do not rely on dispersants. They solve the problem of large particle size and wide particle size distribution of the final product obtained by traditional precipitation methods in the prior art through purely physical means. Ultimately, it is possible to stably prepare ultrafine highly dispersed nanoparticles with small particle size and narrow distribution, which meets the stringent requirements of high-end application fields.

[0031] Furthermore, such as Figures 1 to 4 As shown, the incubation chamber 4 includes a first cylinder 41 and a second cylinder 42. The side wall of the first cylinder 41 is provided with multiple first openings 41a, and a first screen 41b is installed at each first opening 41a. The mesh of the first screen 41b forms a second through hole. The water inlet 41c is located at the bottom of the first cylinder 41, and the rotating shaft 51 is connected to the first cylinder 41. The side wall of the second cylinder 42 is provided with multiple second openings 42a, and a second screen 42b is installed at each second opening 42a. The bottom of the second cylinder 42 is provided with an installation hole 42c, which extends upward through the top of the second cylinder 42. The first cylinder 41 is inserted and fixed in the installation hole 42c, and the first opening 41a is located inside the second cylinder 42.

[0032] The drive assembly 5 drives the first cylinder 41 to rotate, and the first cylinder 41 drives the second cylinder 42 to rotate. A negative pressure space is formed inside the high-speed rotating first cylinder 41. The mixed solution at the bottom of the receiving chamber 1 enters the first cylinder 41 from the water inlet 41c at the bottom of the first cylinder 41. Under the action of centrifugal force, the mixed solution flows out from the mesh of the first screen 41b. At the same time as it flows out, the cylinder wall of the high-speed rotating first cylinder 41 shears the mixed solution. The mixed solution sheared by the first cylinder 41 flows out from the mesh of the second screen 42b under the action of centrifugal force. At the same time as it flows out, the cylinder wall of the high-speed rotating second cylinder 42 shears the mixed solution again. The first cylinder 41 performs initial crushing and dispersion, while the second cylinder 42 further refines the smaller particles after initial screening. This step-by-step processing allows the particles to be finer, resulting in smaller overall particle size and more uniform size. Moreover, the first screen 41b and the second screen 42b act as filtration barriers, allowing only particles smaller than a certain size to pass through, thereby screening out smaller particles. The dual-screen design further narrows the particle distribution range and improves consistency.

[0033] Furthermore, such as Figure 3 and Figure 4 As shown, the second cylindrical body 42 includes a base 421, a chamber 422, and a top cover 423 stacked sequentially from bottom to top. A mounting hole 42c is provided on the base 421, extending upwards through the top cover 423. A second opening 42a is provided on the side wall of the chamber 422. The first cylindrical body 41 is inserted into the mounting hole 42c. A stop plate 411 is fixedly installed at the bottom of the first cylindrical body 41, stopping against the bottom surface of the base 421. The top extends to the outside of the top cover 423. A limiting member 412 is installed on the top of the first cylinder 41. Specifically, the first cylinder 41 extending to the outside of the top cover 423 is provided with an installation thread 413. The bottom of the limiting member 412 is provided with a connecting screw hole. The limiting member 412 is threadedly installed on the top of the first cylinder 41. The limiting member 412 and the stop plate 411 are used to position the base 421, the cylinder 422 and the top cover 423. The rotating shaft 51 is connected to the limiting member 412. Specifically, as shown in the figure... Figure 4 As shown, the top of the limiting member 412 is provided with a mounting screw hole 412a, and the rotating shaft 51 is threadedly fixed in the mounting screw hole 412a, thereby realizing the connection between the rotating shaft 51 and the first cylinder 41.

[0034] Furthermore, such as Figure 3 and Figure 4As shown, the incubation chamber 4 also includes multiple partition plates 421a disposed between the first cylinder 41 and the chamber 422. These partition plates 421a are arranged circumferentially around the first cylinder 41 to divide the space between the first cylinder 41 and the chamber 422 into multiple chambers. Each chamber is used to hold packing material, and each partition plate 421a is fixed to the base 421. In this embodiment of the invention, the packing material is zirconia spheres or alumina spheres. The high-speed rotation of the incubation chamber 4 causes the packing spheres within the chambers to move violently. These hard spheres collide and rub against each other and with the particles at high frequencies, providing the particles with additional and stronger mechanical force. This more effectively breaks down the small agglomerates remaining after primary shearing, further reducing the final powder particle size. Furthermore, the movement of the packing material disturbs the fluid within the chambers, resulting in more thorough mixing of the solution, preventing particle sedimentation or excessively high local concentrations, and ensuring that all particles are subjected to relatively uniform mechanical action, thereby making the particle size distribution more concentrated and narrower.

[0035] Furthermore, such as Figure 1 As shown, the drive assembly 5 also includes a drive motor 52 connected to the rotating shaft 51. The drive motor 52 is mounted on the top of the rotating shaft 51. The rotating shaft 51 extends downward through the top of the housing chamber 1 and the mixing chamber 2. The housing chamber 1 is rotatably connected to the rotating shaft 51, the mixing chamber 2 is fixedly connected to the rotating shaft 51, and the bottom of the rotating shaft 51 is fixedly connected to the incubation chamber 4.

[0036] Furthermore, such as Figure 1 As shown, the apparatus for preparing ultrafine powder also includes a feed pipe 6 for conveying the reaction liquid. The top of the mixing chamber 2 is provided with a first perforation 2a. A rotating shaft 51 passes through the top of the receiving chamber 1, the first perforation 2a, and the bottom of the mixing chamber 2. The bottom of the mixing chamber 2 is fixedly connected to the rotating shaft 51. The feed pipe 6 passes through the receiving chamber 1 and the first perforation 2a, and is connected to the inlet of the atomizing nozzle 31. Specifically, as... Figure 1 As shown, the feed tube 6 includes a first rigid tube 61 and a second rigid tube 62. The first rigid tube 61 extends downward and passes through the top of the receiving chamber 1 and the first through hole 2a in sequence. The first rigid tube 61 is fixedly connected to the top of the receiving chamber 1. The lower end of the first rigid tube 61 is fixedly connected to the atomizing nozzle 31 located at the top in the atomizing assembly 3. The second rigid tube 62 extends downward and passes through the top of the receiving chamber 1 and the first through hole 2a. The second rigid tube 62 is fixedly connected to the top of the receiving chamber 1. The lower end of the second rigid tube 62 extends downward to the bottom of the atomizing assembly 3 and then bends upward. The lower end of the second rigid tube 62 is fixedly connected to the atomizing nozzle 31 located at the bottom in the atomizing assembly 3.

[0037] Furthermore, such as Figure 1 , Figure 5 and Figure 6As shown, the top and bottom of the mixing chamber 2 are respectively provided with a first through hole 2a and a second through hole 2b. A connecting sleeve 23 is fixed in the second through hole 2b. The rotating shaft 51 passes through the first through hole 2a and the connecting sleeve 23 in sequence and is welded and fixed to the connecting sleeve 23, thereby realizing the fixed connection between the mixing chamber 2 and the rotating shaft 51. Moreover, the side wall of the mixing chamber 2 is provided with multiple third openings 21. A third screen 22 is installed at the third opening 21, and the mesh of the third screen 22 forms a first through hole.

[0038] Furthermore, such as Figure 7 As shown, this embodiment of the invention also includes a raw material tank 7, a regulating tank 9, a preparation device 10, and a collection tank 8. The raw material tank 7 stores the reaction raw materials and is connected to the regulating tank 9. The regulating tank 9 is connected to a first rigid pipe 61 or a second rigid pipe 62. The preparation device 10 is the aforementioned ultrafine powder preparation device, and the outlet of the receiving chamber 1 is connected to the collection tank 8. The reaction raw materials are pumped from the raw material tank 7 into the regulating tank 9, where the pH value of the reaction raw materials is adjusted. After adjustment, the raw materials are input into the preparation device for reaction. After the reaction is completed, the mixed solution is output from the outlet and collected in the collection tank 8.

[0039] Furthermore, such as Figure 1 As shown, by adjusting the aperture of the atomizer and the aperture of the third screen 22, this embodiment of the invention can be adapted to cerium sources such as cerium nitrate / cerium chloride and precipitants such as ammonium carbonate / ammonium bicarbonate, and can be extended to the preparation of rare earth oxides such as lanthanum carbonate and cerium hydroxide and general nanomaterials such as calcium carbonate; moreover, the surfactant-free system simplifies the process, avoids the introduction of impurities, and reduces raw material costs by 30%.

[0040] like Figures 1 to 6 As shown, based on the ultrafine powder preparation apparatus of the above-described embodiments of the invention, this embodiment of the invention provides a method for preparing ultrafine powder. Using the ultrafine powder preparation apparatus of the above-described embodiments of the invention, this embodiment of the invention will be described using the preparation of ultrafine, highly dispersed nano-cerium carbonate with a D50 of 58 nm as an example. The method for preparing ultrafine powder of this embodiment of the invention includes the following steps: S1. The reaction liquid is conveyed to the atomizing component 3 to atomize the reaction liquid, and the atomized reaction liquid is horizontally sprayed onto the side wall of the mixing chamber 2 after being impacted from above and below to form a mixed solution. In step S1, the temperature inside the containment chamber 1 is controlled at 50°C by the heat exchange jacket 12. The reaction solution includes a cerium source and a precipitant. The cerium source is a 0.1 mol / L cerium nitrate aqueous solution (without surfactant), which is transported into the mixing chamber 2 through the first rigid pipe 61. The precipitant is a 0.12 mol / L ammonium carbonate aqueous solution (slightly in excess by 10%), which is transported into the mixing chamber 2 through the second rigid pipe 62. The atomizing nozzle is a 0.5 mm aperture atomizer. Both the cerium source and the precipitant are pumped into the mixing chamber 2 by a high-pressure pump at a flow rate of 20 mL / min. The cerium source and the precipitant collide at high speed, achieving uniform mixing of the reactants and shortening the nucleation induction period by more than 50%. This creates conditions for large-scale and uniform nucleation and avoids the coarse particles caused by excessively high local concentrations of the reaction solution from the source.

[0041] S2. Drive the mixing chamber 2 to rotate to shear the mixed solution and discharge the sheared mixed solution from the first through hole into the mixing chamber 2; In step S2, the drive motor 52 drives the mixing chamber 2 to rotate at a high speed of 1200 rpm. The high-speed rotating walls of the mixing chamber 2 shear the mixed solution at high speed. Under the centrifugal force of the mixing chamber 2, the sheared mixed solution flows out from the first through hole.

[0042] The high-speed shearing of the mixing solution by the walls of the mixing chamber 2 breaks up the initially formed crystal nuclei or micro-aggregates, inhibiting their premature agglomeration and growth. At the same time, it further improves the microscopic mixing uniformity of the reactants, increases the nucleation driving force and nucleation rate, significantly shortens the nucleation induction period, and avoids problems such as uneven nucleation, secondary nucleation, or abnormal grain growth that may be caused by excessively long nucleation time.

[0043] S3, The mixed solution accumulates at the bottom of the container 1; In step S3, the mixed solution flowing out of the mixing chamber 2 flows to the bottom of the receiving chamber 1 and accumulates.

[0044] S4. Drive the incubation chamber 4 to rotate so that the mixed solution enters the incubation chamber 4 from the inlet 41c and discharges the mixed solution in the incubation chamber 4 from the second through hole. In step S4, the drive motor 52 drives the first cylinder 41 to rotate, and the first cylinder 41 drives the second cylinder 42 to rotate. Both the first cylinder 41 and the second cylinder 42 rotate at a high speed of 1200 rpm. A negative pressure space is formed inside the high-speed rotating first cylinder 41. The mixed solution at the bottom of the receiving chamber 1 enters the first cylinder 41 through the water inlet 41c at the bottom of the first cylinder 41. Under the action of centrifugal force, the mixed solution flows out from the mesh of the first screen 41b. At the same time as it flows out, the cylinder wall of the high-speed rotating first cylinder 41 shears the mixed solution. The sheared solution... The mixed solution enters between the chamber 422 and the first cylinder 41. The violently moving zirconia or alumina balls and the balls and particles generate high-frequency collisions and friction, which provides the particles with additional and stronger mechanical force, which can more effectively break up the small agglomerates remaining after the primary shearing, and further reduce the final powder particle size. The mixed solution between the chamber 422 and the first cylinder 41 flows out from the mesh of the second screen 42b under the action of centrifugal force. At the same time as it flows out, the cylinder wall of the high-speed rotating second cylinder 42 shears the mixed solution again, further realizing the crushing of particles.

[0045] The incubation chamber 4 regulates the ion concentration gradient around the crystal nucleus through centrifugal shearing, suppressing agglomeration and Austronescent ripening. Under surfactant-free conditions, the product particle size can be controlled from micron to nanometer, with a narrow particle size distribution and 40% better dispersibility than traditional impinging flow technology.

[0046] S5. Repeat step S4 until the preset time is reached, then collect the mixed solution and filter and clean the collected mixed solution.

[0047] In step S5, step S4 is repeated, allowing the mixed liquid to continuously enter, flow out, and enter the incubation chamber 4 to perform multiple shearing operations on the mixed liquid. After 1.5 hours, the mixed solution is discharged and collected from outlet 11, and the collected mixed solution is filtered and washed with deionized water. After washing, it is dried in a vacuum environment at 60°C for 6 hours to obtain the corresponding powder.

[0048] Furthermore, such as Figure 8 As shown, Figure 8 The particle size distribution-bulk density curve obtained from the experiment is... Figure 8 As can be seen, the particle size distribution of the prepared powder is a sharp, narrow, single-peak distribution with no large-particle-size impurities. The median diameter of the powder volume is D50=58nm, with excellent particle size uniformity, low degree of particle hard agglomeration, and excellent dispersibility. It accurately achieves the design goal of preparing ultrafine highly dispersed nanoparticles and verifies the reliability of the preparation of ultrafine highly dispersed nano-cerium carbonate in the embodiments of the present invention.

[0049] Furthermore, this embodiment of the invention also prepared ultrafine, highly dispersed nano-cerium carbonate with a D50 of 106 nm. The temperature inside the containment chamber 1 was controlled at 60 °C by the heat exchange jacket 12. The cerium source was a 0.15 mol / L cerium chloride aqueous solution (without surfactant), and the precipitant was a 0.18 mol / L ammonium bicarbonate aqueous solution (20% excess). A 0.8 mm aperture atomizer was used. Both the cerium source and the precipitant were pumped into the mixing chamber 2 at a flow rate of 50 mL / min using a high-pressure pump. The rotation speed of the mixing chamber 2 and the incubation chamber 4 was 1000 rpm. After 2 hours of circulating shearing in the incubation chamber 4, the mixed solution was discharged and collected from the outlet 11. The collected mixed solution was filtered and washed with deionized water. After washing, it was dried in an air-dried environment at 80 °C for 4 hours to obtain the corresponding powder. At the same time, the corresponding particle size distribution-bulk density-volume accumulation curves were obtained, as shown in the figure. Figure 9 As shown, the particle size distribution of the prepared powder is a sharp, narrow, single-peak distribution with no large-particle-size impurities. The median diameter of the powder volume is D50 = 106 nm, exhibiting excellent particle size uniformity, low degree of particle hard agglomeration, and excellent dispersibility. This precisely achieves the design goal of preparing ultrafine, highly dispersed nanoparticles, verifying the reliability of the preparation of ultrafine, highly dispersed nano-cerium carbonate in the embodiments of this invention.

[0050] In summary, the apparatus and method for preparing ultrafine powder provided by the embodiments of the present invention, through at least one set of atomizing nozzles 31 arranged vertically opposite each other, causes two streams of reaction liquid to collide at high speed after atomization, generating a strong turbulence effect and instantaneous high pressure, enabling the reaction liquid to complete efficient mixing and energy transfer in a very short time, achieving uniform mixing of the reactants, creating conditions for large-scale and uniform nucleation, and avoiding the coarse particles caused by excessively high local concentration of the reaction liquid from the source.

[0051] Subsequently, the driving component 5 drives the mixing chamber 2, which has a first through hole on its side wall, to rotate horizontally. The high-speed rotating mixing chamber 2 shears the mixed solution at high speed, further enhancing the collision, breakage and dispersion of substances in the reaction liquid. This not only breaks up the initially formed crystal nuclei or micro-aggregates and inhibits their premature agglomeration and growth, but also further improves the microscopic mixing uniformity of the reactants, effectively increasing the nucleation driving force and nucleation rate. This significantly shortens the nucleation induction period and effectively avoids problems such as uneven nucleation, secondary nucleation or abnormal grain growth that may be caused by excessively long nucleation time, laying a solid foundation for obtaining fine and uniform initial crystal nuclei.

[0052] Under the centrifugal force of the mixing chamber 2, the mixed solution, sheared by the mixing chamber 2, flows outward from the first through-hole. Finally, the mixed solution flows to the bottom of the receiving chamber 1. The driving component 5 drives the incubation chamber 4 to rotate. A negative pressure space is formed inside the high-speed rotating incubation chamber 4. The mixed solution at the bottom of the receiving chamber 1 enters the incubation chamber 4 through the water inlet 41c at the bottom of the incubation chamber 4. Under the centrifugal force of the incubation chamber 4, the mixed solution flows out from the second through-hole on the chamber wall of the incubation chamber 4. At the same time as it flows out, the high-speed rotating chamber wall of the incubation chamber 4 performs secondary shearing on the mixed solution. The mixed solution flowing out of the incubation chamber 4 re-enters the incubation chamber 4 through the water inlet 41c, thus achieving cyclic shearing of the mixed solution. Through the cyclic shearing of the incubation chamber 4, austenitic ripening is suppressed, which can accelerate the uniform mass transfer of micro-nucleation, improve the mass transfer and reaction efficiency, avoid abnormal particle growth, and the grown particles will also be sheared and dispersed again, thereby preparing ultrafine powder with small particle size and narrow distribution range.

[0053] Compared to traditional precipitation methods, the embodiments of the present invention do not rely on dispersants. They solve the problem of large particle size and wide particle size distribution of the final product obtained by traditional precipitation methods in the prior art through purely physical means. Ultimately, it is possible to stably prepare ultrafine highly dispersed nanoparticles with small particle size and narrow distribution, which meets the stringent requirements of high-end application fields.

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. An apparatus for preparing ultrafine powder, characterized in that, include: Container room (1); A mixing chamber (2) is located inside the receiving chamber (1), and a plurality of first through holes are provided on the side wall of the mixing chamber (2); Atomizing component (3) is provided in the mixing chamber (2). The number of atomizing components (3) is at least one. Each atomizing component (3) includes two atomizing nozzles (31). The outlets of the two atomizing nozzles (31) are arranged opposite each other. The inlet of each atomizing nozzle (31) is used to inject the reaction liquid. An incubation chamber (4) is installed inside the containment chamber (1), and the incubation chamber (4) is located below the mixing chamber (2); The incubation chamber (4) has multiple second through holes on its side wall and a water inlet (41c) at its bottom. The drive assembly (5) includes a rotating shaft (51) which is vertically arranged and extends to the containment chamber (1) at its lower part. The mixing chamber (2) and the incubation chamber (4) are both arranged on the rotating shaft (51). The rotating shaft (51) is used to drive the mixing chamber (2) and the incubation chamber (4) to rotate horizontally.

2. The apparatus for preparing ultrafine powder according to claim 1, characterized in that, The incubation chamber (4) includes a first cylinder (41), a plurality of first openings (41a) are provided on the side wall of the first cylinder (41), a first screen (41b) is installed at the first opening (41a), the mesh of the first screen (41b) forms a second through hole, the water inlet (41c) is located at the bottom of the first cylinder (41), and the rotating shaft (51) is connected to the first cylinder (41).

3. The apparatus for preparing ultrafine powder according to claim 2, characterized in that, The incubation chamber (4) also includes a second cylinder (42), and a plurality of second openings (42a) are provided on the side wall of the second cylinder (42), and a second screen (42b) is installed at each of the second openings (42a). The bottom of the second cylinder (42) is provided with a mounting hole (42c), which extends upward through the top of the second cylinder (42). The first cylinder (41) is inserted and fixed in the mounting hole (42c), and the first opening (41a) is located in the second cylinder (42).

4. The apparatus for preparing ultrafine powder according to claim 3, characterized in that, The second cylindrical body (42) includes a base (421), a chamber (422) and a top cover (423) stacked from bottom to top. The mounting hole (42c) is provided on the base (421) and the mounting hole (42c) extends upward through the top cover (423). The second opening (42a) is provided on the side wall of the chamber (422).

5. The apparatus for preparing ultrafine powder according to claim 4, characterized in that, The first cylindrical body (41) is inserted into the mounting hole (42c). A stop plate (411) is fixedly installed at the bottom of the first cylindrical body (41). The stop plate (411) stops at the bottom surface of the base (421). The top of the first cylindrical body (41) extends to the outside of the top cover (423). A limiting member (412) is installed at the top of the first cylindrical body (41). The limiting member (412) and the stop plate (411) are used to position the base (421), the cylindrical chamber (422) and the top cover (423). The rotating shaft (51) is connected to the limiting member (412).

6. The apparatus for preparing ultrafine powder according to claim 4, characterized in that, The incubation chamber (4) further includes a plurality of partition plates (421a) disposed between the first cylinder (41) and the chamber (422). The plurality of partition plates (421a) are arranged at intervals along the circumference of the first cylinder (41) to divide the space between the first cylinder (41) and the chamber (422) into a plurality of chambers. Each chamber is used to place packing material, and each partition plate (421a) is fixed on the base (421).

7. The apparatus for preparing ultrafine powder according to claim 1, characterized in that, The drive assembly (5) also includes a drive motor (52) connected to the rotating shaft (51); The drive motor (52) is mounted on the top of the rotating shaft (51), which extends downward through the top of the accommodating chamber (1) and the mixing chamber (2). The accommodating chamber (1) is rotatably connected to the rotating shaft (51), the mixing chamber (2) is fixedly connected to the rotating shaft (51), and the bottom of the rotating shaft (51) is fixedly connected to the incubation chamber (4).

8. The apparatus for preparing ultrafine powder according to claim 7, characterized in that, The device for preparing ultrafine powder also includes a feed pipe (6) for conveying the reaction liquid. The top of the mixing chamber (2) is provided with a first perforation (2a), and the rotating shaft (51) passes through the top of the receiving chamber (1), the first perforation (2a) and the bottom of the mixing chamber (2), and the bottom of the mixing chamber (2) is fixedly connected to the rotating shaft (51). The feed pipe (6) passes through the receiving chamber (1) and the first perforation (2a), and the feed pipe (6) is connected to the inlet of the atomizing nozzle (31).

9. The apparatus for preparing ultrafine powder according to claim 8, characterized in that, The feed pipe (6) includes a first rigid pipe (61) and a second rigid pipe (62); The first rigid tube (61) extends downward and passes through the top of the receiving chamber (1) and the first perforation (2a) in sequence. The first rigid tube (61) is fixedly connected to the top of the receiving chamber (1), and the lower end of the first rigid tube (61) is fixedly connected to the atomizing nozzle (31) located above in the atomizing assembly (3). The second rigid tube (62) extends downward through the top of the receiving chamber (1) and the first perforation (2a). The second rigid tube (62) is fixedly connected to the top of the receiving chamber (1). The lower end of the second rigid tube (62) extends downward to the bottom of the atomizing assembly (3) and then bends upward. The lower end of the second rigid tube (62) is fixedly connected to the atomizing nozzle (31) located at the bottom of the atomizing assembly (3).

10. A method for preparing ultrafine powder, characterized in that, The apparatus for preparing ultrafine powder according to any one of claims 1 to 9 includes the following steps: S1. The reaction liquid is conveyed to the atomizing component (3) to atomize the reaction liquid, and the atomized reaction liquid is horizontally sprayed onto the side wall of the mixing chamber (2) after being impacted from above and below to form a mixed solution. S2. Drive the mixing chamber (2) to rotate to shear the mixed solution and discharge the sheared mixed solution from the first through hole into the mixing chamber (2). S3, the mixed solution accumulates at the bottom of the container (1); S4. Drive the incubation chamber (4) to rotate so that the mixed solution enters the incubation chamber (4) from the inlet (41c) and discharges the mixed solution in the incubation chamber (4) from the second through hole. S5. Repeat step S4 until a preset time is reached, then collect the mixed solution and filter and clean the collected mixed solution.

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