Continuous ceramic powder production device and method

Abstract

The invention discloses a continuous ceramic powder production device and method. The continuous ceramic powder production device comprises a gas-powder mixing bin, a molten raw material liquid storage tank, a conveying pipe, a Venturi mixer, a discharged material cooling bin and a discharged material collecting device, the conveying pipe penetrates through the molten raw material liquid storage tank, one end of the conveying pipe is communicated with the gas-powder mixing bin, the other end of the conveying pipe is communicated with the discharging cooling bin, and the discharging cooling bin is communicated with the discharging collecting device; a raw material gas inlet and a seed crystal powder inlet are formed in the gas-powder mixing bin; a molten raw material liquid inlet is formed in the molten raw material liquid storage tank; the venturi mixer is arranged in the conveying pipe, and a liquid suction pipe extending into the molten raw material liquid storage tank is arranged on the venturi mixer. Continuous, particle size-controllable, high-efficiency and high-quality production of the ceramic powder is realized.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic powders, and in particular to a continuous ceramic powder production device and method. Background Art

[0002] Materials are one of the most important pillars of modern science. The development of new materials often brings revolutionary products and processes, provides the necessary tools and conditions for research in other scientific fields, and promotes the progress of the entire industry. With the continuous development of new technologies such as aerospace technology, new energy technology, large-scale integrated circuit technology, and sensor technology, materials are required to have excellent mechanical properties, high insulation, high temperature resistance, and corrosion resistance. Ceramic materials have the characteristics of high melting point, high temperature resistance, high hardness, corrosion resistance, electrical insulation, thermal conductivity, thermal stability, and low expansion coefficient, which perfectly meet the requirements.

[0003] However, traditional methods for preparing ceramic powders, such as aluminum nitride, alumina, and silicon nitride, usually have complex production steps and high costs. At the same time, the ceramic powders produced have coarse particle sizes and insufficient purity, which limits the surface of ceramic powders in high-end applications. In order to solve these problems, researchers have explored a variety of improved technologies aimed at improving the quality of ceramic powders by optimizing synthesis conditions, introducing new additives, or improving sintering technology. These efforts have made some progress in improving material properties, but still face challenges in cost control and environmental sustainability. Therefore, developing a new preparation strategy to achieve efficient, low-cost, and environmentally friendly production of high-quality ceramic powders is of great significance to promoting technological progress in related industries.

[0004] Taking the preparation method of aluminum nitride powder as an example, the preparation methods of aluminum nitride powder mainly include the following:

[0005] Direct nitridation method: Aluminum powder is heated in an ammonia or nitrogen atmosphere to react directly with nitrogen to form aluminum nitride. The reaction equation is:

[0006] 2Al+N2→2AlN

[0007] Although this method is simple, it usually requires high temperature, which easily causes the aluminum powder to melt and agglomerate, and the nitridation is incomplete, and the purity of the obtained aluminum nitride powder is low.

[0008] Carbon thermal reduction method: A carbon source is used to react with aluminum oxide at high temperature in a nitrogen atmosphere to generate aluminum nitride through a carbon thermal reduction process. This method can obtain finer powder particles, but the reaction temperature is high, the energy consumption is large, and it is difficult to control the particle size and shape of the powder. The reaction equation is:

[0009] Al2O3+3C+N2→AlN+3CO

[0010] High-temperature self-propagating synthesis method: By igniting a mixture of aluminum powder and carbon powder, self-propagating high-temperature synthesis is carried out in a nitrogen environment. This method can obtain high-purity aluminum nitride powder in a relatively short time, but it has high requirements for equipment and is difficult to achieve large-scale production.

[0011] Chemical vapor deposition (CVD): Aluminum nitride thin film is deposited on a substrate at high temperature through a gas phase reaction, and then powder is obtained by mechanical grinding. This method can obtain powders with high purity and specific particle size distribution, but the cost is high and is not conducive to large-scale production.

[0012] Sol-gel method: The precursor is prepared by chemical solution reaction, and then aluminum nitride powder is obtained through drying, calcination and other steps. This method can better control the chemical composition and microstructure of the powder, but the process steps are more and the cost is relatively high.

[0013] Carbon thermal reduction-nitridation method: This is a method that combines carbon thermal reduction and nitridation processes. Aluminum nitride powder is prepared by high-temperature treatment of a mixture of carbide and aluminum oxide in a nitrogen atmosphere. This method can prepare high-purity, fine-grained aluminum nitride powder at a lower temperature and is a relatively effective preparation technology. The equation is:

[0014] Al2O3+3C→2Al+3CO (reaction equation without nitrogen in the first step)

[0015] Al+1 / 2N2→AlN (reaction equation in the second step under nitrogen atmosphere)

[0016] It can be seen that the existing preparation methods have the problems of incomplete chemical reaction, high impurity content, and inability to prepare high-purity (above 99.99%) ceramic powders. At the same time, continuous production cannot be achieved. Production is based on each furnace, and there are certain differences in the performance of different batches of powders. In addition, the impurity removal process is complicated and requires many additional equipment. Summary of the invention

[0017] In view of this, the object of the present invention is to provide a continuous ceramic powder production device and method to achieve continuous, size-controllable, high-efficiency and high-quality production of ceramic powder.

[0018] In order to achieve the above object, the present invention provides the following technical solutions:

[0019] A continuous ceramic powder production device comprises an air-powder mixing bin, a molten raw material liquid storage tank, a conveying pipe, a venturi mixer, a discharge cooling bin and a discharge collecting device; the conveying pipe passes through the molten raw material liquid storage tank and one end of the conveying pipe is connected to the air-powder mixing bin, and the other end of the conveying pipe is connected to the discharge cooling bin, and the discharge cooling bin is connected to the discharge collecting device; the air-powder mixing bin is provided with a raw material gas inlet and a seed crystal powder inlet, and the molten raw material liquid storage tank is provided with a molten raw material liquid inlet; the venturi mixer is arranged in the conveying pipe, and the venturi mixer is provided with a suction pipe extending into the molten raw material liquid storage tank.

[0020] As a preferred technical solution, the Venturi mixer includes a conical nozzle, a negative pressure suction chamber, a mixing chamber, a diffusion chamber and a pipette. The conical nozzle is connected to the delivery pipe, and a negative pressure suction chamber is formed around the conical nozzle. The mixing chamber is arranged at the front end of the conical nozzle and the negative pressure suction chamber. The diffusion chamber is connected to the mixing chamber through a throat, and the pipette is connected to the negative pressure suction chamber.

[0021] As a preferred technical solution, one-way valves are respectively provided at the inlet and outlet of the delivery pipe passing through the molten raw material liquid storage tank.

[0022] As a preferred technical solution, a liquid level sensor is provided in the molten raw material liquid storage tank, the molten raw material liquid storage tank is a heating and heat preservation tank, and the conveying pipe is a heat preservation pipe.

[0023] A method for producing ceramic powder using a continuous ceramic powder production device comprises the following steps:

[0024] (1) injecting a molten raw material liquid into a molten raw material liquid storage tank;

[0025] (2) introducing the raw gas and the seed crystal powder into a gas-powder mixing bin for mixing;

[0026] (3) The raw material gas mixed with the seed crystal powder passes through the Venturi mixer. Due to the Venturi effect, the molten raw material liquid in the molten raw material liquid storage tank is sucked into the Venturi mixer. In the Venturi mixer, the raw material gas is broken into bubbles and contacts and reacts with the molten raw material liquid to generate ceramic powder;

[0027] (4) The ceramic powder generated by the reaction enters a discharge cooling bin for cooling under the conveyance of the raw material gas, and then enters a discharge collecting device for collection under the conveyance of the raw material gas.

[0028] As a preferred technical solution, the molten raw material liquid is molten aluminum liquid, molten silicon liquid, molten boron liquid, molten zirconium liquid or molten titanium liquid, and the raw material gas is nitrogen or oxygen.

[0029] As a preferred technical solution, the seed crystal powder is the same ceramic powder as the ceramic powder generated by the reaction.

[0030] The beneficial effects of the present invention are:

[0031] 1. The present invention designs a continuous ceramic powder production device, which uses a venturi mixer to break the raw gas into a uniform bubble flow at the micron or even nanometer level, and sucks the molten raw liquid into the venturi mixer to fully contact and react with the raw gas to generate ceramic powder, thereby realizing the continuous production of micron / nano ceramic powder, preventing the quality difference between different batches caused by multiple batches of production, and effectively reducing the problems of agglomeration, insufficient reaction, etc. in conventional production methods.

[0032] 2. The present invention dopes high-purity ceramic powder into the raw gas as seed crystal powder, which on the one hand promotes the reaction, and at the same time, the doped seed crystal powder can prevent the coarsening and agglomeration of powder particles caused by strong exothermic reaction, further improve the nano-degree of powder, greatly improve the production efficiency, and also prevent the agglomeration of ceramic powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration:

[0034] Figure 1 It is a structural schematic diagram of a continuous ceramic powder production device;

[0035] Figure 2 for Figure 1 Enlarged view of point A in the middle. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0037] like Figure 1A continuous ceramic powder production device is shown, comprising an air-powder mixing bin 1, a molten raw material liquid storage tank 2, a conveying pipe 3, a venturi mixer 4, a discharge cooling bin 5 and a discharge collecting device 6; the conveying pipe 3 passes through the molten raw material liquid storage tank 2 and one end of the conveying pipe 3 is connected to the air-powder mixing bin 1, and the other end of the conveying pipe 3 is connected to the discharge cooling bin 5, and the inlet and outlet of the conveying pipe 3 passing through the molten raw material liquid storage tank 2 are respectively provided with check valves 7 and 8, and the discharge cooling bin 5 is connected to the discharge collecting device 6; the air-powder mixing bin 1 is provided with a raw material liquid storage tank 2, and the discharge cooling bin 5 is connected to the discharge collecting device 6. There are a material gas inlet 9 and a seed crystal powder inlet 10, the molten raw material liquid storage tank 2 is provided with a molten raw material liquid inlet 11, and a liquid level sensor 12 is provided in the molten raw material liquid storage tank 2; the molten raw material liquid storage tank 2 is a heating and insulation box, which has heating and insulation capabilities, and can adjust the temperature in real time, so as to facilitate the melting and insulation of molten raw material liquids with different melting points; the delivery pipe 2 is an insulation pipe; the Venturi mixer 4 is arranged in the delivery pipe 3, and the Venturi mixer 4 is provided with a suction pipe 13 extending into the molten raw material liquid storage tank 2.

[0038] The specific structure of the venturi mixer 4 is as follows: Figure 2 As shown, the Venturi mixer 4 includes a conical nozzle 14, a negative pressure suction chamber 15, a mixing chamber 16, a diffusion chamber 17 and a suction pipe 13. The conical nozzle 14 is connected to the delivery pipe 3. The negative pressure suction chamber 15 is formed around the conical nozzle 14. The mixing chamber 16 is arranged at the front end of the conical nozzle 14 and the negative pressure suction chamber 15. The diffusion chamber 17 is connected to the mixing chamber 16 through a throat, and the suction pipe 13 is connected to the negative pressure suction chamber 15.

[0039] Taking the preparation method of aluminum nitride powder as an example, the method of producing ceramic powder using a continuous ceramic powder production device includes the following steps:

[0040] (1) injecting molten aluminum liquid into the molten raw material liquid storage tank 2 through the molten raw material liquid inlet 11;

[0041] (2) nitrogen and aluminum nitride seed crystal powder (high-purity aluminum nitride powder) are introduced into the gas-powder mixing chamber 1 through the raw gas inlet 9 and the seed crystal powder inlet 10 for mixing;

[0042] (3) Open the one-way valve 7 at the inlet of the delivery pipe 3, and the nitrogen mixed with the aluminum nitride seed crystal powder passes through the venturi mixer 4. Due to the Venturi effect, the aluminum liquid in the molten raw material liquid storage tank 2 is sucked into the venturi mixer 4 by the suction pipe 13. In the venturi mixer 4, the nitrogen is broken into bubbles and reacts with the aluminum liquid to generate aluminum nitride powder; the reaction equation is: 2Al+N2→2AlN;

[0043] (4) The aluminum nitride powder generated by the reaction enters the discharge cooling bin 5 for cooling under the conveyance of nitrogen, and then enters the discharge collecting device 6 for collection under the conveyance of nitrogen.

[0044] Through the above embodiments, those skilled in the art should understand that the molten raw material liquid can be other ceramic raw materials in a molten state, such as molten aluminum liquid, molten silicon liquid, molten boron liquid, molten zirconium liquid or molten titanium liquid, etc.; the raw material gas can be other raw material gases, such as nitrogen or oxygen; and the reaction generates ceramic powders such as silicon nitride, boron nitride, aluminum oxide, zirconium oxide, titanium oxide, etc.

[0045] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A continuous ceramic powder production device, characterized in that: It includes an air-powder mixing bin, a molten raw material liquid storage tank, a conveying pipe, a venturi mixer, a discharge cooling bin and a discharge collecting device; the conveying pipe passes through the molten raw material liquid storage tank and one end of the conveying pipe is connected to the air-powder mixing bin, and the other end of the conveying pipe is connected to the discharge cooling bin, and the discharge cooling bin is connected to the discharge collecting device; the air-powder mixing bin is provided with a raw material gas inlet and a seed crystal powder inlet, and the molten raw material liquid storage tank is provided with a molten raw material liquid inlet; the venturi mixer is arranged in the conveying pipe, and the venturi mixer is provided with a suction pipe extending into the molten raw material liquid storage tank.

2. The continuous ceramic powder production device according to claim 1, characterized in that: The venturi mixer includes a conical nozzle, a negative pressure suction chamber, a mixing chamber, a diffusion chamber and a pipette. The conical nozzle is connected to the delivery pipe. A negative pressure suction chamber is formed around the conical nozzle. The mixing chamber is arranged at the front end of the conical nozzle and the negative pressure suction chamber. The diffusion chamber is connected to the mixing chamber through a throat, and the pipette is connected to the negative pressure suction chamber.

3. The continuous ceramic powder production device according to claim 1, characterized in that: One-way valves are respectively arranged at the inlet and outlet of the delivery pipe passing through the molten raw material liquid storage tank.

4. The continuous ceramic powder production device according to claim 1, characterized in that: A liquid level sensor is arranged in the molten raw material liquid storage tank, the molten raw material liquid storage tank is a heating and heat preservation tank, and the conveying pipe is a heat preservation pipe.

5. A method for producing ceramic powder using a continuous ceramic powder production device, characterized in that: The following steps are involved: (1) injecting a molten raw material liquid into a molten raw material liquid storage tank; (2) introducing the raw gas and the seed crystal powder into a gas-powder mixing bin for mixing; (3) The raw material gas mixed with the seed crystal powder passes through the Venturi mixer. Due to the Venturi effect, the molten raw material liquid in the molten raw material liquid storage tank is sucked into the Venturi mixer. In the Venturi mixer, the raw material gas is broken into bubbles and contacts and reacts with the molten raw material liquid to generate ceramic powder; (4) The ceramic powder generated by the reaction enters a discharge cooling bin for cooling under the conveyance of the raw material gas, and then enters a discharge collecting device for collection under the conveyance of the raw material gas.

6. The method for producing ceramic powder according to claim 1, characterized in that: The molten raw material liquid is molten aluminum liquid, molten silicon liquid, molten boron liquid, molten zirconium liquid or molten titanium liquid, and the raw material gas is nitrogen or oxygen.

7. The method for producing ceramic powder according to claim 1, characterized in that: The seed crystal powder is the same ceramic powder as the ceramic powder generated by the reaction.

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