System and method for continuous liquid phase reaction for ultrafine powder production

Abstract

A system and method for preparing ultrafine powder by liquid phase continuous reaction, comprising: a fast mixer and an aeration reactor connected in sequence, the fast mixer comprising a feeding device and a rotating device, one end of the feeding device having an inlet for liquid phase material to be mixed, the other end extending into the mixing zone of the fast mixer, and a liquid distributor provided on the side of the feeding device, the liquid distributor facing the rotating device to deliver reaction solution, the rotating device being used to shear, rotate and cut the reaction solution to mix the reaction solution sufficiently and to carry out primary reaction to produce primary powder slurry; the reaction zone of the aeration reactor being provided with an aeration device, the aeration device generating a gas film rising from bottom to top to realize gas floating effect on the counter- contacting powder particles, so that the falling speed of the powder particles reaching the bottom of the aeration reactor is consistent with the speed of complete reaction, and continuous preparation is realized. The ultrafine powder has narrow particle size distribution and good dispersibility, the system is simple, practical and easy to use, and is suitable for industrial application under different process conditions.

Description

Technical Field

[0001] This invention belongs to the field of chemical equipment technology, and specifically refers to a system and method for preparing ultrafine powders by continuous liquid-phase reaction. Background Technology

[0002] According to the consensus of my country's mineral processing industry, ultrafine powders are defined as powders with a particle size of 100% less than 30 μm. In recent years, due to the significant differences between ultrafine powders and traditional metallic materials in their optical, magnetic, acoustic, electrical, and mechanical properties, ultrafine powder technology has been widely applied in various fields such as medicine, chemical industry, electronics, energy, and construction. The preparation processes for ultrafine powders include gas-phase methods, liquid-phase methods, and solid-phase methods, among which the liquid-phase method is also widely used to synthesize high-purity ultrafine powders.

[0003] Currently, ultrafine powders produced by the liquid phase method are mostly prepared using conventional batch stirred tank reactors. Liquid materials are directly poured into the reactor or added dropwise through a funnel for stirring and mixing, followed by a reaction to obtain the product powder. Conventional batch stirred tank reactors suffer from problems such as uneven mixing of raw materials, localized supersaturation, a wide particle size distribution in the resulting product, low production efficiency due to the intermittent operation, and difficulty in controlling batch-to-batch stability of the product. Summary of the Invention

[0004] To address the above technical problems, the present invention aims to provide a system and method for preparing ultrafine powders through continuous liquid-phase reaction. A rapid mixer is used to achieve rapid and thorough mixing of the reaction solution, and the generated primary powder slurry is quickly output to an aeration reactor as seed crystals for further growth. Simultaneously, the settling rate of the powder particles is controlled by an upward-flowing gas film generated by the aeration device, ensuring that the powder particles are fully reacted and have uniform particle size when they fall to the bottom of the aeration reactor, thereby achieving continuous preparation of ultrafine powders.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A system for preparing ultrafine powders via continuous liquid-phase reaction includes:

[0007] A rapid mixer and an aeration reactor connected in sequence,

[0008] The rapid mixer includes a feeding device and a rotating device. One end of the feeding device has an inlet for the liquid phase material to be mixed, and the other end extends into the mixing zone of the rapid mixer. A liquid distributor is provided on the side. The liquid distributor feeds the reaction solution to the rotating device. The reaction solution is rapidly and thoroughly mixed by the shearing, rotation and cutting of the rotating device, and a primary reaction is carried out to produce a primary powder slurry.

[0009] The reaction zone of the aeration reactor is equipped with an aeration device. The aeration device generates an air film that rises from the bottom to achieve an air flotation effect on the powder particles in reverse contact. This ensures that the descent rate of the powder particles before they reach the bottom of the aeration reactor and are discharged from the system is consistent with their rate of complete reaction, thus realizing the continuous preparation of ultrafine powders.

[0010] In some technical solutions, the rotating device includes a rotating component and a driving device.

[0011] The rotating component is an impeller, the liquid distributor is arranged adjacent to the impeller, and the driving device drives the impeller to rotate at high speed, so that the reaction solution can be rapidly mixed under strong shearing, impact and dispersion.

[0012] Alternatively, the rotating component is a packed bed, and the driving device drives the packed bed to rotate at high speed to generate a hypergravity field. The liquid distributor is located in the hypergravity field, so that the reaction solution is dispersed and torn into droplets, liquid films or liquid filaments under the strong hypergravity, thereby promoting the micro-mixing and mass transfer process of the materials.

[0013] In some technical solutions, the feeding device is equipped with a hollow distribution pipe. One end of the hollow distribution pipe is connected to a solution storage tank through a feeding pipeline, and the other end is sprayed with the reaction solution into the rotating device area through a liquid distributor.

[0014] In some technical solutions, the hollow fabric tubes are multiple tubes arranged in parallel, and the multiple hollow fabric tubes are evenly distributed along the circumference of the rotating device.

[0015] In some technical solutions, an aeration device is installed at the bottom of the aeration reactor, and a demister is installed at the top.

[0016] The aeration device is equipped with an aeration membrane, which is connected to an external gas source storage tank through an air inlet pipe; the demister is used to remove droplets from the aeration gas before discharging it, and the treated discharged gas flows back to the gas source storage tank.

[0017] In some technical solutions, the upper side of the aeration reactor is provided with a feed inlet, and a perforated plate distributor is installed below the feed inlet to evenly distribute the primary powder slurry into the aeration reactor; and / or,

[0018] Both the rapid mixer and the aeration reactor are equipped with heating and insulation jackets or external heat exchangers.

[0019] In some technical solutions, the aeration reactor is a long and slender reaction tower.

[0020] The upper side of the reaction tower is provided with a feed inlet, a perforated plate distributor is installed below the feed inlet, and a discharge outlet is provided at the bottom of the reaction tower for discharging ultrafine powder slurry from the system.

[0021] The lower part of the reaction tower is equipped with an aeration membrane, which is connected to an external gas source storage tank through an air inlet pipe to produce an air flotation effect. The top of the reaction tower is equipped with a demister to remove liquid droplets from the aeration gas before discharge. The treated discharged gas flows back to the gas source storage tank.

[0022] A method for preparing ultrafine powder by continuous liquid-phase reaction, suitable for the above-mentioned system, includes the following steps:

[0023] The reaction solutions from multiple solution storage tanks are fed into the mixing zone of the rapid mixer in parallel. They are then sprayed into the rotating device area by the liquid distributor. The rotating device uses shearing, rotation and cutting to quickly and thoroughly mix the reaction solutions and carry out the primary reaction to produce a primary powder slurry.

[0024] The primary powder slurry from the rapid mixer is continuously transported to the aeration reactor, where it is evenly distributed from top to bottom. It comes into counter-current contact with the rising air film generated by the aeration device, creating effective buoyancy. When the powder particles fall to the bottom of the aeration reactor, the reaction is complete and the particle size is uniform.

[0025] The ultrafine powder slurry from the aeration reactor is further processed to obtain ultrafine powder.

[0026] In some technical solutions, the aeration gas source is air;

[0027] And / or, the aeration gas source includes a portion of the gas used to adjust the pH of the reaction, or an oxidizing gas used for oxidation, or hydrogen used for the hydrogenation reaction.

[0028] In some technical solutions, the method is applied to the continuous production of ferric phosphate, ferromanganese phosphate, ternary precursors, and sodium ion cathode material precursors.

[0029] The present invention, by employing the above technical solution, has at least the following beneficial effects:

[0030] 1. This invention achieves rapid and thorough mixing of reaction raw materials through a rapid mixer. The residence time of the reactants in the rapid mixer is extremely short. After the primary powder is formed, it immediately leaves the rapid mixer and enters the aeration reactor for further growth. This can effectively control the size of the product particles and improve the uniformity of the product particle size.

[0031] 2. By adjusting the aeration pressure at the bottom of the aeration reactor, this invention can make the falling rate of solid particles consistent with the rate at which the reaction is completed. In conjunction with a rapid mixer, it can achieve continuous preparation of ultrafine powders, improve production efficiency, and shorten the production cycle.

[0032] 3. The system of the present invention is simple, practical, and easy to use. It is suitable for industrial needs under different process conditions and has good industrial application prospects. Its specific application is the continuous production of ultrafine powders prepared by liquid-phase reaction of ferric phosphate, ferromanganese phosphate, ternary precursors, sodium ion cathode material precursors, etc. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings and their markings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the system for preparing ultrafine powders by continuous liquid-phase reaction with an impeller, as described in an embodiment of the present invention.

[0035] Figure 2 This is a schematic diagram of the system for preparing ultrafine powders by continuous liquid-phase reaction with a packed bed, as described in an embodiment of the present invention.

[0036] The meanings of the symbols in the diagram are as follows:

[0037] 1 - Rapid mixer, 101 - First feeding pipe, 102 - Second feeding pipe, 103 - Nozzle, 104 - Motor, 105 - Rotating component;

[0038] 201 – First solution storage tank; 202 – Second solution storage tank;

[0039] 3 - Aeration reactor, 301 - Feed inlet, 302 - Perforated plate distributor, 303 - Aeration membrane, 304 - Air inlet pipe, 305 - Air source storage tank, 306 - Demister, 307 - Discharge outlet. Detailed Implementation

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0041] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0042] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0043] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0045] According to a first aspect of the present invention, a system for preparing ultrafine powders by continuous liquid-phase reaction is provided. (See also...) Figure 1-2 The system includes a rapid mixer 1 and an aeration reactor 3 connected in sequence. The rapid mixer 1 achieves rapid and thorough mixing of the reaction solution, and the resulting primary powder is quickly transferred to the aeration reactor 3 as seed crystals for further growth. At the same time, by adjusting the aeration pressure at the bottom of the aeration reactor 3, the powder particles are completely reacted and have uniform particle size when they fall to the bottom of the aeration reactor 3, thereby realizing the continuous preparation of ultrafine powder.

[0046] In the above embodiments, the rapid mixer 1 is used to rapidly and thoroughly mix at least two reaction solutions and carry out a primary reaction to generate fine primary powder, which acts as a seed crystal.

[0047] In some embodiments, the rapid mixer 1 includes at least two hollow feeding tubes, such as a first feeding tube 101 and a second feeding tube 102, for adding at least two reaction solutions into the rapid mixer 1; one end of each hollow feeding tube is connected to an external solution storage tank, such as a first solution storage tank 201 and a second solution storage tank 202, and the bottom of the other end is sealed, with a liquid distributor, such as a nozzle 103, provided on the side wall; the rapid mixer 1 also includes a rotating device that rotates at high speed, using its shearing, rotation and cutting to quickly and thoroughly mix the reaction solutions and carry out primary reactions to produce primary powder slurry.

[0048] It should be noted that the specific number of the hollow material distribution tubes is not limited, as long as the mixing requirements of the reaction solution are met. The liquid distributors on the hollow material distribution tubes face the rotating device. In the preferred embodiment above, multiple hollow material distribution tubes are arranged in parallel and evenly distributed along the circumference of the rotating device. Multiple streams of liquid-phase reactants are evenly sprayed into the area of ​​the rotating device, and the reaction solution is rapidly and thoroughly mixed through the shearing, rotation, and cutting of the rotating device.

[0049] Specifically, the rotating device includes a rotating component 105 and a motor 104. The rotating component 105 can be as follows: Figure 1 The high-speed rotating impeller in the middle can also be like... Figure 2 The high-speed rotating packed bed in the process involves two or more reaction solutions being sprayed near the impeller through nozzles. Driven by motor 104, the impeller rotates at high speed, and the reaction solutions are rapidly mixed under intense shearing, impact, and dispersion. Similarly, in the case of a high-speed rotating packed bed, two or more reaction solutions are sprayed near the packed bed through nozzles. Driven by motor 104, the packed bed rotates at high speed, generating a supergravity effect. Under this intense supergravity, the reaction solutions are dispersed and torn into droplets, liquid films, or liquid filaments. The large phase interface promotes the microscopic mixing and mass transfer processes of the materials.

[0050] In the above embodiments, the lower part of the rapid mixer 1 is provided with a discharge port, and a pump body is provided on the connecting pipeline between the discharge port and the aeration reactor 3 to provide slurry conveying power; or, the upper part of the rapid mixer 1 is provided with an overflow port, and the primary powder slurry is output to the aeration reactor 3 through the overflow port.

[0051] In the above embodiment, the aeration reactor 3 is a long and slender reaction tower. A feed inlet 301 is provided on the upper side of the reaction tower. A perforated plate distributor 302 is provided below the feed inlet 301 inside the reaction tower to distribute the primary powder slurry in the rapid mixer 1 evenly into the aeration reactor 3. A discharge port 307 for outputting ultrafine powder slurry is provided at the bottom of the aeration reactor 3.

[0052] In some embodiments, an aeration device is provided at the bottom of the aeration reactor 3. The aeration device is equipped with an aeration membrane 303. The aeration membrane 303 is connected to an external air source storage tank 305 through an air inlet pipe 304 to generate an air flotation effect and reduce the settling rate of solid particles. The air film generated by the aeration membrane 303 rising from bottom to top provides effective buoyancy to the solid particles falling from top to bottom, which can achieve the required descent rate of solid particles, that is, the descent rate of solid particles before reaching the bottom of the reactor and being discharged from the system is consistent with the rate at which the reaction is completed.

[0053] In a preferred embodiment, a demister 306 is installed at the top of the aeration reactor 3. The gas generated during aeration is discharged after being de-dropped by the demister 306, and then returned to the gas source storage tank 305 after further treatment for reuse as an aeration gas source. Specifically, the demister 306 is selected as a loose fiber bed demister.

[0054] According to another aspect of the present invention, a method for preparing ultrafine powder by continuous liquid-phase reaction is provided, comprising the following steps:

[0055] S10: The reaction solution from multiple solution storage tanks is fed into the mixing zone of the rapid mixer 1 in parallel. It is then sprayed into the rotating device area by the liquid distributor. The reaction solution is rapidly and thoroughly mixed by the shearing, rotation and cutting of the rotating device, and a primary reaction is carried out to produce a primary powder slurry.

[0056] S20: The primary powder slurry generated by the rapid mixer 1 is continuously transported to the aeration reactor 3, where it is evenly distributed from top to bottom. It forms an effective buoyancy by contacting the rising air film generated by the aeration device in the opposite direction. When the powder particles fall to the bottom of the aeration reactor, the reaction is complete and the particle size is uniform, resulting in an ultrafine powder slurry.

[0057] The aeration gas source is conventional compressed air, but depending on the needs of the reaction, the aeration gas source may also include some gases that participate in the reaction, such as ammonia, carbon dioxide, sulfur dioxide, chlorine, hydrogen sulfide, nitrogen dioxide, hydrogen chloride, etc., used to adjust the pH value of the reaction; oxidizing gases such as oxygen and ozone, used to perform oxidation; and process gases that participate in the reaction, such as hydrogen for hydrogenation reaction.

[0058] S30: The ultrafine powder slurry from the aeration reactor 3 is further processed to obtain ultrafine powder.

[0059] The subsequent processing of ultrafine powder slurry includes, but is not limited to, heat exchange, filtration, washing, drying, and pulverization.

[0060] The system and method described above can be applied to the continuous production of ultrafine powders prepared by liquid-phase reaction of ferric phosphate, ferromanganese phosphate, ternary precursors, sodium ion cathode material precursors, etc. Heating devices can be installed on the outer walls of the rapid mixer 1 and the aeration reactor 3 as needed. Specifically, these devices can be heating and insulation jackets or external heat exchangers to control the temperature required for the reaction. Valves and flow meters can be installed on the corresponding pipelines for on / off control and flow monitoring.

[0061] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A system for preparing ultrafine powders via continuous liquid-phase reaction, characterized in that, include: A rapid mixer and an aeration reactor connected in sequence, The rapid mixer includes a feeding device and a rotating device. One end of the feeding device has an inlet for the liquid phase material to be mixed, and the other end extends into the mixing zone of the rapid mixer. A liquid distributor is provided on the side. The liquid distributor feeds the reaction solution to the rotating device. The reaction solution is rapidly and thoroughly mixed by the shearing, rotation and cutting of the rotating device, and a primary reaction is carried out to produce a primary powder slurry. The feeding device is equipped with a hollow distribution pipe. One end of the hollow distribution pipe is connected to the solution storage tank through the feeding pipeline, and the other end is sprayed into the rotating device area through the liquid distributor. The upper side of the aeration reactor is provided with a feed inlet, and a perforated plate distributor is installed below the feed inlet to evenly distribute the primary powder slurry into the aeration reactor. An aeration device is installed at the bottom of the aeration reactor. The aeration device is equipped with an aeration membrane, which is connected to an external air source storage tank through an air inlet pipe. The reaction zone of the aeration reactor is equipped with an aeration device. The aeration device generates an air film that rises from the bottom to achieve an air flotation effect on the powder particles in reverse contact. This ensures that the descent rate of the powder particles before they reach the bottom of the aeration reactor and are discharged from the system is consistent with their rate of complete reaction, thus realizing the continuous preparation of ultrafine powders.

2. The system according to claim 1, characterized in that, The rotating device includes a rotating component and a driving device. The rotating component is an impeller, the liquid distributor is arranged adjacent to the impeller, and the driving device drives the impeller to rotate at high speed, so that the reaction solution can be rapidly mixed under strong shearing, impact and dispersion. Alternatively, the rotating component is a packed bed, and the driving device drives the packed bed to rotate at high speed to generate a hypergravity field. The liquid distributor is located in the hypergravity field, so that the reaction solution is dispersed and torn into droplets, liquid films or liquid filaments under the strong hypergravity, thereby promoting the micro-mixing and mass transfer process of the materials.

3. The system according to claim 1, characterized in that, The hollow fabric tubes are multiple tubes arranged in parallel, and the multiple hollow fabric tubes are evenly distributed along the circumference of the rotating device.

4. The system according to claim 1, characterized in that, A demister is installed at the top of the aeration reactor. The demister is used to remove droplets from the aeration gas before discharging it, and the treated discharged gas is returned to the gas source storage tank.

5. The system according to claim 1, characterized in that, Both the rapid mixer and the aeration reactor are equipped with heating and insulation jackets or external heat exchangers.

6. The system according to claim 1, characterized in that, The aeration reactor is a long and slender reaction tower. The upper side of the reaction tower is provided with a feed inlet, a perforated plate distributor is installed below the feed inlet, and a discharge outlet is provided at the bottom of the reaction tower for discharging ultrafine powder slurry from the system. The lower part of the reaction tower is equipped with an aeration membrane, which is connected to an external gas source storage tank through an air inlet pipe to produce an air flotation effect. The top of the reaction tower is equipped with a demister to remove liquid droplets from the aeration gas before discharge. The treated discharged gas flows back to the gas source storage tank.

7. A method for preparing ultrafine powder by continuous liquid-phase reaction, characterized in that, The system suitable for any one of claims 1-6 includes the following steps: The reaction solutions from multiple solution storage tanks are fed into the mixing zone of the rapid mixer in parallel. They are then sprayed into the rotating device area by the liquid distributor. The rotating device uses shearing, rotation and cutting to quickly and thoroughly mix the reaction solutions and carry out the primary reaction to produce a primary powder slurry. The primary powder slurry from the rapid mixer is continuously transported to the aeration reactor, where it is evenly distributed from top to bottom. It comes into counter-current contact with the rising air film generated by the aeration device, creating effective buoyancy. When the powder particles fall to the bottom of the aeration reactor, the reaction is complete and the particle size is uniform. The ultrafine powder slurry from the aeration reactor is further processed to obtain ultrafine powder.

8. The method according to claim 7, characterized in that, The aeration source is air; And / or, the aeration gas source includes a portion of the gas used to adjust the pH of the reaction, or an oxidizing gas used for oxidation, or hydrogen used for the hydrogenation reaction.

9. The method as described in claim 8, characterized in that, The method is applied to the continuous production of ferric phosphate, ferromanganese phosphate, ternary precursors, and sodium ion cathode material precursors.

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