A method and system for fluidized synthesis of tiniocl powder

Abstract

The application discloses a method and system for synthesizing TiNCl powder in a fluid state. The method comprises the following steps: capturing an agent in a fluidized bed, exposing the surface of the agent to capture TiNCl crystal nuclei generated in a gas phase reaction based on TiCl4 and NH3 in a specific temperature range and depositing and growing the TiNCl crystal nuclei into TiNCl powder, and finally separating the TiNCl powder through grinding or cleaning. The application avoids the problems of long synthesis time, harsh conditions and low efficiency in a traditional precursor conversion method, solves the problem of difficulty in obtaining powder due to small supersaturation of a reaction system, has a simple process flow, is easy to scale up and mass produce, and has good economic and social benefits.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of materials and chemical industry, and relates to powder preparation, in particular to a method and system for fluidized synthesis of TiNCl powder. BACKGROUND

[0002] TiNCl is a metal nitrogen halide with a sandwich layered structure, in which the Ti-N layer has a strong covalent bond and exhibits electronic conductivity, while the Ti-Cl layer is held together by van der Waals forces, forming a polyhedral channel that not only stores hydrogen but also provides a fast channel for the storage and transport of Li + , Na + , Mg + , thereby attracting widespread attention in the fields of superconductivity, energy storage, and photocatalysis. Recently, TiNCl has been considered as a promising new generation of metal-ion battery material (Journal of Energy Storage, 2024, 78, 110105). However, the efficient synthesis of TiNCl still faces great difficulties, hindering the practical application from the laboratory to the industry.

[0003] Currently, TiNCl is mainly synthesized by precursor conversion method based on TiCl4 and NH3, that is, first, gaseous or liquid TiCl4 and NH3 are reacted to generate a primary precursor mixture under the protection of inert gas in a horizontal or vertical reactor (Mater. Res. Bull., 2022, 153, 111896; Sci. China. Mater. 2022, 65(11): 2942-2948; J. Mater. Chem., 2009, 19, 2573-2582). Since the reaction path of TiCl4 and NH3 is very complex, there are many parallel reactions, and it is very sensitive to temperature. In the horizontal and vertical reactors, the heat and mass transfer efficiency is low, resulting in a large number of by-products, including TiCl3(NH2), TiCl2(NH2)2, TiCl(NH2)3, TiCl4 x NH3, TiCl3(NH2), TiCl(NH2)3, (NH4)2TiCl6 and NH4Cl, etc. It is very difficult to synthesize TiNCl directly. In order to remove the by-products, the primary precursor needs to be calcined in flowing NH3 at 400℃ for 3-10h to obtain a secondary precursor mixed powder. Finally, the secondary precursor is mixed with a small amount of NH4Cl and sealed in a high-vacuum quartz tube, and then placed in a horizontal furnace with a temperature gradient and heated for 1-3 weeks (J. Electrochem. Soc., 2004, 151, A843). The powder is purified by chemical vapor transport migration to obtain high crystallinity TiNCl. This method is very time-consuming and has a small yield. The maximum reported laboratory yield is about 200mg (Condens. Matter., 2022, 7, 33). Recently, Tanaka et al (ACS Omega 2022, 7, 6375-6380) proposed to use NaNH2 as a nitrogen source to synthesize TiNCl. First, TiCl4 and NaNH2 are frozen with liquid nitrogen and sealed in a high-vacuum glass tube. Then, the sealed glass tube is gradually heated to 150℃ within 12h and kept for 1-2 days to obtain a primary powder. Then, the primary powder is sealed in a quartz tube and calcined at 400℃-230℃ for 1 day to obtain TiNCl powder. Since the raw materials are flammable and explosive, and the reaction releases a lot of heat, the synthesis conditions are very harsh, and there are still many difficulties in actual production.

[0004] In view of the above problems, the present application provides a method and system for fluidized synthesis of TiNCl powder, a new synthesis temperature range and synthesis path are found, and an efficient synthesis method is developed. The one-step synthesis of TiNCl powder on the surface of the capturing agent in the fluidized bed avoids the problems of long synthesis time, harsh conditions and low efficiency of the traditional precursor conversion method, and solves the problem of difficulty in obtaining powder due to small supersaturation of the reaction system. Moreover, the process flow is simple and easy to scale up. SUMMARY

[0005] The present application aims to provide a method and system for fluidized synthesis of TiNCl powder, and the key problem to be solved is that the reaction path of TiCl4 and NH3 is complex, there are many by-products, and the product composition is sensitive to temperature, which is not matched with the existing reactor and is difficult to efficiently and directionally synthesize TiNCl powder. A new process for efficient and directional synthesis of TiNCl powder by capturing TiNCl crystal nucleus synthesized by one-step gas deposition through a capturing agent in a fluidized bed with high heat and mass transfer efficiency in a specific temperature range is proposed.

[0006] In order to achieve these purposes, the first aspect of the present application provides a method for fluidized synthesis of TiNCl powder, which comprises:

[0007] The capturing agent captures TiNCl crystal nucleus generated based on the reaction of titanium source gas and nitrogen source gas and grows into TiNCl powder in a fluidized state at 400-530 DEG C, and then separates the capturing agent and TiNCl powder through a separation process.

[0008] The second aspect of the present application provides a system for fluidized synthesis of TiNCl powder, which comprises a capturing agent feeding device 1, a deposition fluidized bed 2, a powder collecting device 3, a cyclone separation device 4 and a heat preservation pipeline 5.

[0009] The discharge port of the capturing agent feeding device 1 is connected with the feeding port of the deposition fluidized bed 2 through a pipeline and a material valve; the bottom feeding port of the deposition fluidized bed 2 is connected with titanium source gas, nitrogen source gas and inert gas through a pipeline and a gas valve; the discharge port of the deposition fluidized bed 2 is connected with the feeding port of the powder collecting device 3 through a pipeline and a material valve; the gas outlet of the deposition fluidized bed 2 is connected with the gas inlet of the cyclone separation device 4 through the heat preservation pipeline 5; the discharge port of the cyclone separation device 4 is connected with the feeding port of the deposition fluidized bed 2 through a pipeline; and the gas outlet of the cyclone separation device 4 is connected with a tail gas treatment device.

[0010] The third aspect of the present application further provides a method for fluidized synthesis of TiNCl powder based on the above-mentioned system, which comprises the following steps:

[0011] The capturing agent enters the deposition fluidized bed 2 through the material valve and pipeline in the capturing agent feeding device 1, the inert gas enters the deposition fluidized bed 2 to clean the capturing agent, after reaching the reaction temperature, the titanium source gas titanium tetrachloride and the nitrogen source gas ammonia enter the deposition fluidized bed 2 to directly synthesize TiNCl based on the gas phase reaction and are captured by the capturing agent. The tail gas and part of the fine powder of the deposition fluidized bed 2 enter the cyclone separation device 4 through the heat preservation pipeline 5 to realize the secondary synthesis of TiNCl and the separation of the tail gas and the fine powder. The separated fine powder enters the deposition fluidized bed 2 again through the pipeline, and the tail gas enters the tail gas treatment device through the gas outlet of the cyclone separation device 4. After the reaction is completed, the TiNCl powder synthesized in the deposition fluidized bed 2 enters the powder collecting device 3 through the pipeline and the material valve to obtain the target powder. The target powder is separated from the capturing agent and the TiNCl powder through a separation process, the capturing agent is returned to the capturing agent feeding device 1 for repeated use, and the TiNCl powder is used as a product.

[0012] One of the features of the present application is that the synthesis temperature range of TiNCl is 400-530 DEG C; in the system, the temperature range of the deposition fluidized bed is controlled to be 400-530 DEG C; in the above temperature range, it can be specifically 400 DEG C, 420 DEG C, 430 DEG C, 450 DEG C, 470 DEG C, 480 DEG C, 500 DEG C, 510 DEG C, 530 DEG C and the range between any two of the above values, all of which can realize the present application.

[0013] The capturing agent can be selected from any one or a mixture of at least two of SiO2, Al2O3, LiCl, NaCl, KCl and CaCl2.

[0014] The second feature of the present application is that the separation process includes self-grinding and screening of a ball mill, solution cleaning and filtering or centrifugal separation of a centrifuge. The self-grinding of the ball mill does not need to add the ball milling medium tungsten carbide grinding ball.

[0015] The third feature of the present application is that the temperature of the heat preservation pipeline 5 is controlled to be greater than or equal to 300 DEG C, and the temperature of the heat preservation pipeline 5 is greater than or equal to 300 DEG C, which can realize the purpose of the present application. When the temperature is above 300 DEG C, the higher the temperature, the higher the efficiency, but the energy consumption will increase. If it is necessary to control the energy consumption, the temperature of the heat preservation pipeline 5 can be controlled to be below 600 DEG C. Of course, the temperature of the heat preservation pipeline 5 can be controlled to be 350 DEG C-450 DEG C.

[0016] The fourth feature of the present application is that the molar ratio of the titanium source gas titanium tetrachloride to the nitrogen source gas ammonia is greater than or equal to 1, and preferably the molar ratio is 1-2 and any value between them.

[0017] The fifth feature of the present application is that the carrier gas for the titanium source gas titanium tetrachloride can be an inert gas, and the gas inlet at the bottom of the deposition fluidized bed is an inert gas, and the inert gas includes any one or a mixture of at least two of argon, helium, and nitrogen. The inert gas can be used as a cleaning gas for the capture agent, a fluidizing gas, and a raw material carrier gas, etc. The inert gas can be mixed and used in any molar ratio of the above-mentioned gases.

[0018] In the present application, the synthesis flow state of the titanium source gas titanium tetrachloride and the nitrogen source gas ammonia can be generated by a fluidized bed, and preferably can be generated by a deposition fluidized bed.

[0019] Compared with the prior art, the present application has the following advantages:

[0020] (1) The process flow is simple. In the traditional precursor conversion method, powder can be obtained only after the synthesis of a precursor, the heat treatment of the precursor, and the purification of the precursor. The present application directly synthesizes one step based on the gas phase, which significantly shortens the process flow.

[0021] (2) High synthesis efficiency. The traditional process requires about 3 weeks to synthesize 200 mg of sample at a time, and the synthesis efficiency is about 3.9 x 10 -4 g·h -1 While the present process requires only about 60 minutes (10 g·h -1 ) to synthesize 10 g of powder at a time in a laboratory small-size reactor. The yield is large and the time is short, and the synthesis efficiency is improved by about 5 orders of magnitude.

[0022] (3) Easy to scale up to industrial scale. The traditional precursor conversion method uses horizontal or vertical tube reactors with low heat and mass transfer efficiency, which is difficult to operate continuously and has obvious scale-up effect, making it difficult to scale up to industrial scale. The present application uses a fluidized bed reaction system, which not only solves the problems of temperature sensitivity and complex reaction path of the reaction system, but also solves the problem of difficult homogeneous nucleation of the reaction to obtain powder, and can be continuously produced in batches, which is suitable for industrial scale-up. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings are used to provide further explanation of the present application, and constitute a part of the specification, together with embodiments of the present application, to explain the present application, and do not constitute a limitation of the present application.

[0024] Figure 1 The configuration schematic diagram of the TiNCl powder synthesis system of the present application is shown in Figure 1.

[0025] Figure 2 The XRD pattern of the TiNCl powder obtained in Example 3 is shown in Figure 3.

[0026] Figure 3 The SEM pattern of the TiNCl powder obtained in Example 4 is shown in Figure 4.

[0027] Reference signs:

[0028] 1, capturing agent feeding device; 2, deposition fluidized bed; 3, powder collecting device; 4, cyclone separation device; 5, heat preservation pipeline. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described in detail below in combination with the drawings and examples.

[0030] Example 1

[0031] In combination with Figure 1 , the system for fluidized synthesis of TiNCl powder used in this embodiment includes a capturing agent feeding device 1, a deposition fluidized bed 2, a powder collecting device 3, a cyclone separation device 4, and a heat preservation pipeline 5.

[0032] The discharge port of the capturing agent feeding device 1 is connected to the feed port of the deposition fluidized bed 2 through a pipeline and a material valve; the bottom feed port of the deposition fluidized bed 2 is connected to titanium source gas, nitrogen source gas, and inert gas through a pipeline and a gas valve; the discharge port of the deposition fluidized bed 2 is connected to the feed port of the powder collecting device 3 through a pipeline and a material valve; the gas outlet of the deposition fluidized bed 2 is connected to the gas inlet of the cyclone separation device 4 through the heat preservation pipeline 5; the discharge port of the cyclone separation device 4 is connected to the feed port of the deposition fluidized bed 2 through a pipeline; and the gas outlet of the cyclone separation device 4 is connected to a tail gas treatment device.

[0033] Example 2

[0034] This embodiment uses the method for synthesizing TiNCl powder in the system of Example 1, which specifically includes the following steps:

[0035] The capturing agent enters the deposition fluidized bed 2 through a material valve and a pipeline in the capturing agent feeding device 1, and the inert gas first enters the deposition fluidized bed 2 to clean the capturing agent; after reaching the reaction temperature, the titanium source gas titanium tetrachloride and the nitrogen source gas ammonia enter the deposition fluidized bed 2 to directly synthesize TiNCl based on a gas phase reaction and be captured by the capturing agent. The tail gas and part of the fine powder of the deposition fluidized bed 2 enter the cyclone separation device 4 through the heat preservation pipeline 5 to realize the secondary synthesis of TiNCl and separate the tail gas from the fine powder. The separated fine powder enters the deposition fluidized bed 2 again through a pipeline, and the tail gas enters a tail gas treatment device through the gas outlet of the cyclone separation device 4. After the reaction is completed, the TiNCl powder synthesized in the deposition fluidized bed 2 enters the powder collecting device 3 through a pipeline and a material valve to obtain the target powder. The target powder is separated from the capturing agent and the TiNCl powder through a separation process, the capturing agent is returned to the capturing agent feeding device 1 for repeated use, and the TiNCl powder is used as a product.

[0036] Example 3

[0037] In this example, based on the above-mentioned example 2, the SiO2 powder with an average particle size of about 30 μm was selected as the capturing agent, the reaction temperature of the deposition fluidized bed 2 was 420°C, the inert gas was argon, the molar ratio of the nitrogen source gas titanium tetrachloride to the nitrogen source gas ammonia was 1, the synthesis time was 30 minutes, the temperature of the heat preservation pipeline 5 was 350°C, and the powder collecting device obtained the coated powder, and after self-grinding and screening, the TiNCl powder was obtained. Figure 2 The XRD pattern of the obtained TiNCl powder was shown in the figure, from which it can be seen that the powder was single-phase TiNCl powder, and the elemental composition analysis Ti / N / Cl was about 1 / 0.99 / 1.01.

[0038] Example 4

[0039] In this example, based on the above-mentioned example 2, the NaCl powder with an average particle size of about 60 μm was selected as the capturing agent, the reaction temperature of the deposition fluidized bed 2 was 500°C, the inert gas was nitrogen, the molar ratio of the nitrogen source gas titanium tetrachloride to the nitrogen source gas ammonia was 1.8, the synthesis time was 60 minutes, the temperature of the heat preservation pipeline 5 was 400°C, and the powder collecting device obtained the coated powder, and after water washing and filtration, the TiNCl powder was obtained. Figure 3 The SEM pattern of the obtained TiNCl powder was shown in the figure, from which it can be seen that the hollow powder assembled by the sheet TiNCl was obtained, and the maximum transverse size of the single sheet was about 10 μm.

[0040] Example 5

[0041] In this example, based on the above-mentioned example 2, the Al2O3 powder with an average particle size of about 30 μm, the TiN powder with an average particle size of 40 μm, and the KCl mixture with an average particle size of 10 μm were selected as the capturing agent, the reaction temperature of the deposition fluidized bed 2 was 450°C, the inert gas was helium, the molar ratio of the nitrogen source gas titanium tetrachloride to the nitrogen source gas ammonia was 1.4, the synthesis time was 60 minutes, the temperature of the heat preservation pipeline 5 was 480°C, and the powder collecting device obtained the coated powder, and after self-grinding in the ball mill and water washing and filtration, or centrifugal separation, 10 g of TiNCl powder was obtained, and the average particle size of the powder was about 1.2 μm.

[0042] Example 6

[0043] In this embodiment, on the basis of the above-mentioned embodiment 2, CaCl2 powder with an average particle size of about 100 μm, LiCl powder with an average particle size of 20 μm, and KCl mixture with an average particle size of 35 μm are selected as the capturing agent, the reaction temperature of the deposition fluidized bed 2 is 480℃, the inert gas is a mixture of argon and nitrogen, the molar ratio of the nitrogen source gas titanium tetrachloride to the nitrogen source gas ammonia is 1.6, the synthesis time is 120 minutes, the temperature of the heat preservation pipeline 5 is 410℃, and the powder collecting device obtains coated powder, and after water washing, filtration and centrifugal separation, TiNCl powder with an average particle size of about 10 μm is obtained.

[0044] The upper and lower limits of the process parameters (such as temperature, time, etc.) of the present application and the interval values can all realize the present method, and examples are not listed one by one here.

[0045] The contents not described in detail in the present application can all adopt the conventional technical knowledge in the art.

[0046] Finally, it should be explained that the above examples are only used to illustrate the technical solutions of the present application and are not limited. Although the present application is described in detail with reference to the examples, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and they should all be covered in the scope of the claims of the present application.

Claims

1. A method for fluidized bed synthesis of TiNCl powder, the method comprising: The trapping agent captures TiNCl crystal nuclei generated by the reaction of titanium tetrachloride gas and ammonia gas in a fluidized state at 400-530℃ and grows them into TiNCl powder. The trapping agent and TiNCl powder are then separated through a separation process. The trapping agent is any one or a mixture of at least two of SiO2, Al2O3, LiCl, NaCl, KCl, CaCl2, and TiN.

2. The method according to claim 1, characterized in that, The fluidized state is generated using a fluidized bed.

3. The method according to claim 1, characterized in that, The molar ratio of titanium source gas to nitrogen source gas is ≥1.

4. The method according to claim 1, characterized in that, The separation process includes self-grinding and sieving, solution washing and filtration, or centrifugal separation.

5. A system for fluidized bed synthesis of TiNCl powder, characterized in that, The system includes: The trapping agent feeding device (1), the sedimentation fluidized bed (2), the powder collection device (3), the cyclone separator (4), and the insulated pipe (5); The outlet of the capture agent feeding device (1) is connected to the inlet of the deposition fluidized bed (2) through a pipe and a material valve. The bottom inlet of the deposition fluidized bed (2) is connected to the titanium source gas, nitrogen source gas and inert gas through a pipe and a gas valve. The outlet of the deposition fluidized bed (2) is connected to the inlet of the powder collecting device (3) through a pipe and a material valve. The outlet of the deposition fluidized bed (2) is connected to the inlet of the cyclone separator (4) through a heat-insulating pipe (5). The outlet of the cyclone separator (4) is connected to the inlet of the deposition fluidized bed (2) through a pipe. The outlet of the cyclone separator (4) is connected to the exhaust gas treatment device.

6. The system for fluidized bed synthesis of TiNCl powder according to claim 5, characterized in that, The temperature of the insulated pipe (5) is controlled to be greater than or equal to 300℃.

7. The system for fluidized bed synthesis of TiNCl powder according to claim 5, characterized in that, The inert gas includes any one or a mixture of at least two of argon, helium, and nitrogen.

8. The system for fluidized bed synthesis of TiNCl powder according to claim 5, characterized in that, The temperature of the sedimentation fluidized bed is controlled at 400–530°C.

9. The system for fluidized bed synthesis of TiNCl powder according to claim 5, characterized in that, The exhaust gas and some fine powder generated by the sedimentation fluidized bed (2) are used to achieve secondary synthesis of TiNCl in the cyclone separator (4).

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