Atmosphere continuous sintering furnace for preparing aluminum oxynitride powder

Abstract

The invention discloses an atmosphere continuous sintering furnace for preparing aluminum oxynitride powder, which comprises an atmosphere continuous sintering furnace body which is sequentially provided with a preheating section, a high-temperature section and a cooling section along a material flowing direction; the feeding vacuum unit is arranged at the feeding end of the atmosphere continuous sintering furnace body and is in sealed connection with the feeding end of the atmosphere continuous sintering furnace body, and the raw materials are isolated through a feeding vacuum chamber and then conveyed into the atmosphere continuous sintering furnace body; and the discharging vacuum unit is arranged at the discharging end of the atmosphere continuous sintering furnace body and is in sealed connection with the discharging end of the atmosphere continuous sintering furnace body, and the finished products processed by the atmosphere continuous sintering furnace body are subjected to isolation treatment through a discharging vacuum chamber and then are conveyed outwards. The device can isolate air and ensure the purity of nitrogen in the furnace body, so that high-purity aluminum oxynitride powder is synthesized, the productivity is improved, and meanwhile, the energy consumption is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparing aluminum oxynitride powder, and particularly relates to an atmosphere continuous sintering furnace for preparing aluminum oxynitride powder. Background Art

[0002] As a material with excellent optical, mechanical, high-temperature resistance and chemical stability properties, aluminum oxynitride shows great potential in both military and civilian fields. Its common preparation method is divided into two steps. First, aluminum oxynitride powder needs to be synthesized, and then the powder is formed and sintered. Currently, the main preparation method of the powder is carbothermal reduction method. By using carbon and alumina as raw materials, a reaction occurs in a high-temperature and high-purity nitrogen environment to generate aluminum oxynitride powder.

[0003] The conventional equipment currently used for preparing aluminum oxynitride powder is a vertical or horizontal atmosphere carbon tube furnace. Such equipment adopts a single-chamber design and cannot achieve continuous feeding and discharging. The materials need to be processed batch by batch, and the single sintering cycle is as long as 8 - 12 hours (including cooling time), and the daily production capacity is less than 10 kg. Moreover, the start and stop of the equipment are required for the sintering of each batch of materials, thus increasing a large amount of energy consumption.

[0004] The traditional continuous furnace adopts a through-kiln design, and there is a certain amount of air inside the furnace body, so it is impossible to isolate the air, and it is impossible to ensure the nitrogen purity inside the furnace body. Therefore, it is impossible to synthesize high-purity aluminum oxynitride powder, which does not meet the preparation conditions of aluminum oxynitride and is not suitable for the preparation of aluminum oxynitride powder. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides an atmosphere continuous sintering furnace for preparing aluminum oxynitride powder, which can isolate the air, ensure the nitrogen purity inside the furnace body, thereby synthesizing high-purity aluminum oxynitride powder, improving the production capacity, and reducing the energy consumption at the same time.

[0006] To achieve the above object, the technical solution adopted by the present invention is: an atmosphere continuous sintering furnace for preparing aluminum oxynitride powder, comprising:

[0007] An atmosphere continuous sintering furnace body, which is sequentially arranged as a preheating section, a high-temperature section and a cooling section along the material flow direction;

[0008] A feeding vacuum unit, which is arranged at the feeding end of the atmosphere continuous sintering furnace body and is hermetically connected, and conveys the raw materials into the atmosphere continuous sintering furnace body after being isolated through the feeding vacuum chamber;

[0009] And a discharging vacuum unit, which is arranged at the discharging end of the atmosphere continuous sintering furnace body and is hermetically connected, and conveys the finished products processed by the atmosphere continuous sintering furnace body outwards after being isolated through the discharging vacuum chamber.

[0010] Furthermore, the atmosphere continuous sintering furnace body is a horizontal structure throughout;

[0011] The furnace body consists of a shell, a heat insulation layer, a heating element, and a channel from the outside to the inside, and a transmission guide rail is arranged in the channel;

[0012] At least one set of dust collection pipelines is arranged on the furnace body at intervals. One end of the dust collection pipeline penetrates the bottom wall of the furnace body and leads to the channel, and the other end of the dust collection pipeline leads to the outside and is connected to a dust collection tank;

[0013] At least one set of nitrogen injection pipelines is arranged on the furnace body at intervals. One end of the nitrogen injection pipeline penetrates the side wall of the furnace body and leads to the channel, and the other end of the nitrogen injection pipeline leads to the outside and is connected to a nitrogen supply device.

[0014] Furthermore, the heat insulation layer is made of graphite felt purified at a high temperature of 2300 °C and is fixed to the shell by graphite bolts.

[0015] Furthermore, the heating element is made of high-purity isostatic graphite with a density ≥ 1.85 g / cm3.

[0016] Furthermore, the furnace body is divided into three sections, including:

[0017] The preheating section includes three temperature zones of 500 °C, 800 °C, and 1200 °C;

[0018] The high-temperature section includes three temperature zones of 1600 °C, 1950 °C, and 1600 °C;

[0019] The cooling section includes a 1200 °C buffer temperature zone, a circulating water cooling zone, and a forced air cooling zone, and no heating element is provided in the cooling section.

[0020] Furthermore, measuring devices are arranged on the furnace body, including a temperature measuring device, a vacuum gauge, and / or a pressure measuring device;

[0021] And / or, a safety valve and / or an exhaust port are also arranged on the furnace body.

[0022] Furthermore, the feeding vacuum unit includes:

[0023] A feeding vacuum chamber, and a feeding side vacuum pump group is connected to the feeding vacuum chamber through a feeding side vacuum pipeline;

[0024] A feeding conveyor belt for carrying materials into the feeding vacuum chamber, and the feeding conveyor belt is close to the feeding vacuum chamber;

[0025] A feeding flap valve, and a feeding flap valve is arranged at the connection between the feeding conveyor belt and the feeding vacuum chamber;

[0026] A furnace inlet conveyor belt, one end of which is close to the feeding vacuum chamber and the other end extends into the furnace body;

[0027] And an inlet furnace gate valve is provided at the connection between the feeding vacuum chamber and the inlet furnace conveyor belt.

[0028] Furthermore, a feeding oil cylinder is provided on the feeding conveyor, a furnace inlet oil cylinder is provided on the furnace inlet conveyor, a feeding proximity switch is provided in the feeding vacuum chamber, and a nitrogen delivery component is provided on the feeding vacuum chamber;

[0029] When the material is placed on the feeding conveyor belt, the inlet furnace gate valve opens, the feeding oil cylinder pushes the material into the feeding vacuum chamber. After the feeding proximity switch touches the material, the feeding oil cylinder retracts, the inlet furnace gate valve closes, and at the same time, the vacuum pump group starts. When the pressure in the feeding vacuum chamber ≤ 5 Pa, the vacuum pump group stops, and nitrogen is filled into the feeding vacuum chamber by the nitrogen delivery component. After the pressure reaches the same as the pressure in the furnace body, the inlet furnace gate valve and the outlet furnace gate valve open; the furnace inlet oil cylinder starts and pushes the material into the furnace body, and the inlet furnace gate valve and the outlet furnace gate valve close.

[0030] Furthermore, the discharge vacuum unit includes:

[0031] A discharge vacuum chamber, and the discharge side vacuum pump group is connected to the discharge vacuum chamber through a discharge side vacuum pipeline;

[0032] An outlet furnace conveyor belt, one end extends into the furnace body, and the other end is close to the discharge vacuum chamber;

[0033] An outlet furnace gate valve is provided at the connection between the discharge vacuum chamber and the outlet furnace conveyor belt;

[0034] A discharge conveyor belt is close to the discharge vacuum chamber and is used to output the finished product;

[0035] And a discharge gate valve is provided at the connection between the discharge conveyor belt and the discharge vacuum chamber.

[0036] Furthermore, a discharge oil cylinder is provided on the opposite side of the discharge conveyor belt, a discharge proximity switch is provided in the discharge vacuum chamber, and a nitrogen delivery component is provided on the feeding vacuum chamber;

[0037] The outlet furnace gate valve opens, the outlet furnace conveyor belt pushes the finished product in the furnace into the discharge vacuum chamber. After the discharge proximity switch touches the material, the outlet furnace gate valve closes, the discharge gate valve closes, the discharge side vacuum pump group starts. When the pressure in the vacuum chamber ≤ 5 Pa, the vacuum pump group stops, and nitrogen is filled into the discharge vacuum chamber until the pressure is the same as that in the furnace. The discharge gate valve opens and the finished product is pushed to the discharge conveyor belt through the discharge oil cylinder.

[0038] The beneficial effects of adopting this technical solution:

[0039] The traditional single-chamber furnace body design has low output and high energy consumption. By using the continuous furnace designed in the present invention, the production capacity can be significantly improved while the energy consumption is reduced. The design of the present invention is adopted to meet the sintering of aluminum oxynitride ceramics.

[0040] By adding a vacuum pump group and improving the inlet and outlet, the present invention ensures the nitrogen purity in the furnace body, thus avoiding the problem of the nitrogen purity in the furnace body decreasing due to air entering the buffer section when the inlet and outlet plug valves are opened and closed. Brief Description of the Drawings

[0041] Figure 1 It is a schematic structural diagram of an atmosphere continuous sintering furnace for preparing aluminum oxynitride powder according to the present invention;

[0042] Figure 2 It is a sectional view of an atmosphere continuous sintering furnace for preparing aluminum oxynitride powder in an embodiment of the present invention;

[0043] Figure 3 It is a sectional view of a partial section of an atmosphere continuous sintering furnace for preparing aluminum oxynitride powder in an embodiment of the present invention;

[0044] Figure 4 It is a schematic structural diagram of a feed vacuum unit in an embodiment of the present invention;

[0045] Figure 5 It is a schematic structural diagram of a discharge vacuum unit in an embodiment of the present invention.

[0046] Among them, 1 is the furnace body, 11 is the shell, 12 is the heat insulation layer, 13 is the heating element, 14 is the channel, 15 is the conveying guide rail, 16 is the dust collection pipeline, 17 is the dust collection tank, 8 is the nitrogen injection pipeline; 21 is the feed vacuum chamber, 22 is the feed side vacuum pump group, 23 is the feed side vacuum pipeline, 24 is the feed conveyor belt, 25 is the feed plug valve, 26 is the furnace inlet conveyor belt, 27 is the furnace inlet plug valve, 28 is the feed oil cylinder, 29 is the feed proximity switch; 31 is the discharge vacuum chamber, 32 is the discharge side vacuum pump group, 33 is the discharge side vacuum pipeline, 34 is the furnace outlet conveyor belt, 35 is the furnace outlet plug valve, 36 is the discharge conveyor belt, 37 is the discharge plug valve, 38 is the discharge oil cylinder, 39 is the discharge proximity switch. Detailed Embodiments

[0047] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described below with reference to the accompanying drawings.

[0048] In this embodiment, as shown in Figure 1 and Figure 2 shown, the present invention provides an atmosphere continuous sintering furnace for preparing aluminum oxynitride powder, including:

[0049] The atmosphere continuous sintering furnace body is successively arranged as a preheating section, a high-temperature section and a cooling section along the material flow direction;

[0050] The feeding vacuum unit is arranged at the feeding end of the atmosphere continuous sintering furnace body and is hermetically connected. After isolating the original material through the feeding vacuum chamber, it is conveyed into the atmosphere continuous sintering furnace body;

[0051] And the discharging vacuum unit is arranged at the discharging end of the atmosphere continuous sintering furnace body and is hermetically connected. After isolating the finished product processed by the atmosphere continuous sintering furnace body through the discharging vacuum chamber, it is conveyed outwards.

[0052] Embodiment 1

[0053] As Figure 2 and Figure 3 shown, the atmosphere continuous sintering furnace body is a horizontal structure throughout;

[0054] The furnace body consists of a shell, a heat insulation layer, a heating element and a channel from outside to inside. A conveying guide rail is arranged in the channel;

[0055] At least one set of dust collection pipelines is arranged on the furnace body at intervals. One end of the dust collection pipeline penetrates the bottom wall of the furnace body and leads to the channel, and the other end of the dust collection pipeline leads to the outside and is connected to a dust collection tank;

[0056] At least one set of nitrogen injection pipelines is arranged on the furnace body at intervals. One end of the nitrogen injection pipeline penetrates the side wall of the furnace body and leads to the channel, and the other end of the nitrogen injection pipeline leads to the outside and is connected to a nitrogen supply device.

[0057] Preferably, the heat insulation layer is made of graphite felt purified at a high temperature of 2300 °C and is fixed to the shell by graphite bolts.

[0058] Preferably, the heating element is made of high-purity isostatic graphite with a density ≥ 1.85 g / cm3 to ensure its service life.

[0059] Preferably, the furnace body is divided into three sections, including:

[0060] The preheating section includes three temperature zones of 500 °C, 800 °C and 1200 °C;

[0061] The high-temperature section includes three temperature zones of 1600 °C, 1950 °C and 1600 °C;

[0062] The cooling section includes a 1200 °C buffer temperature zone, a circulating water cooling zone and a forced air cooling zone. The cooling section is not provided with a heating element.

[0063] Preferably, measuring devices are arranged on the furnace body, including a temperature detector, a vacuum gauge and / or a pressure measuring device;

[0064] And / or, a safety valve and / or an exhaust port are further provided on the furnace body.

[0065] The specific implementation process is as follows:

[0066] The structure of the aluminum oxynitride powder continuous sintering furnace described in the present invention is as Figure 1 shown; the design dimensions of the atmosphere continuous sintering furnace in this embodiment are as Figure 2 shown; the sectional view of the furnace body in this embodiment is as Figure 2 shown; the partial sectional view of the furnace body in this embodiment is as Figure 3 shown. In the figure, (a) is a partial longitudinal sectional view, and (b) is a partial transverse sectional view. The furnace body is a circular horizontal structure as a whole, and a circular double-layer water-cooled jacket structure is adopted. The inner layer and the electrode port are welded with 304 stainless steel plates, and the connecting flange and the outer layer are welded with Q235B carbon steel plates. The overall heating power is 500KW, and all temperature zones can be adjusted according to process requirements.

[0067] Embodiment 2

[0068] As Figure 4 shown, the feeding vacuum unit includes:

[0069] A feeding vacuum chamber, and the feeding side vacuum pump group is connected to the feeding vacuum chamber through a feeding side vacuum pipeline;

[0070] A feeding conveyor belt for carrying materials into the feeding vacuum chamber, and the feeding conveyor belt is close to the feeding vacuum chamber;

[0071] A feeding flap valve is provided at the connection between the feeding conveyor belt and the feeding vacuum chamber;

[0072] A furnace inlet conveyor belt, one end of which is close to the feeding vacuum chamber and the other end extends into the furnace body;

[0073] And a furnace inlet flap valve is provided at the connection between the feeding vacuum chamber and the furnace inlet conveyor belt.

[0074] Preferably, a feeding oil cylinder is provided on the feeding conveyor, a proximity switch is provided in the feeding vacuum chamber, and a nitrogen delivery component is provided on the feeding vacuum chamber.

[0075] When the material is placed on the feeding conveyor belt, the feeding flap valve opens, the feeding oil cylinder pushes the material into the feeding vacuum chamber. After the proximity switch touches the material, the feeding oil cylinder retracts, the feeding flap valve closes, and at the same time the vacuum pump group starts. When the pressure in the feeding vacuum chamber ≤ 5 Pa, the vacuum pump group stops, and nitrogen is filled into the feeding vacuum chamber by the nitrogen delivery component. After the pressure reaches the same as the pressure in the furnace body, the furnace inlet flap valve and the furnace outlet flap valve open, the furnace inlet oil cylinder starts and pushes the material into the furnace body, and the furnace inlet flap valve and the furnace outlet flap valve close.

[0076] AsFigure 5 As shown, the discharging vacuum unit includes:

[0077] A discharging vacuum chamber, and a discharging-side vacuum pump group is connected to the discharging vacuum chamber through a discharging-side vacuum pipeline;

[0078] An out-of-furnace conveyor belt, one end of which extends into the furnace body and the other end is close to the discharging vacuum chamber;

[0079] An out-of-furnace flap valve is arranged at the connection between the discharging vacuum chamber and the out-of-furnace conveyor belt;

[0080] A discharging conveyor belt is close to the discharging vacuum chamber and is used for outputting finished products;

[0081] And a discharging flap valve, and a discharging flap valve is arranged at the connection between the discharging conveyor belt and the discharging vacuum chamber.

[0082] Preferably, a discharging oil cylinder is arranged on the opposite side of the discharging conveyor belt, a proximity switch is arranged in the discharging vacuum chamber, and a nitrogen delivery component is arranged on the feeding vacuum chamber;

[0083] When the out-of-furnace flap valve is opened, the out-of-furnace conveyor belt pushes the finished products in the furnace into the discharging vacuum chamber. After the proximity switch touches the material, the out-of-furnace flap valve closes, the discharging flap valve closes, and the discharging-side vacuum pump group starts. When the pressure in the vacuum chamber ≤ 5 Pa, the vacuum pump group stops, and nitrogen is filled into the discharging vacuum chamber until the pressure is the same as that in the furnace. Then the discharging flap valve is opened and the finished products are pushed to the discharging conveyor belt through the discharging oil cylinder.

[0084] In the specific implementation process:

[0085] The designed dimensions of the atmosphere continuous sintering furnace of the present invention are as Figure 2 shown, and the vacuum chamber of the atmosphere continuous furnace in this embodiment is as Figure 3 shown. It is integrally welded with 304 stainless steel plates, and the connecting flanges and Q235B carbon steel plates are welded. It mainly includes an oil cylinder, a flap valve, a roller conveyor belt and a guide wheel. As Figure 3 shown, the vacuum chamber is mechanically sealed and connected to the vacuum pump group and the furnace body to ensure that the ultimate vacuum degree of the atmosphere continuous furnace of the present invention ≤ 5 Pa. Through two-stage flap valves, the vacuum chamber is a nitrogen purging buffer section between the furnace bodies to realize the oxygen-free transmission of materials.

[0086] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. An atmosphere continuous sintering furnace for preparing aluminum oxynitride powder, characterized in that, Comprising: An atmosphere continuous sintering furnace body, which is successively arranged as a preheating section, a high-temperature section and a cooling section along the material flow direction; A feeding vacuum unit, which is arranged at the feeding end of the atmosphere continuous sintering furnace body and is hermetically connected, and conveys the raw materials into the atmosphere continuous sintering furnace body after being isolated through the feeding vacuum chamber; And a discharging vacuum unit, which is arranged at the discharging end of the atmosphere continuous sintering furnace body and is hermetically connected, and conveys the finished products processed by the atmosphere continuous sintering furnace body outwards after being isolated through the discharging vacuum chamber.

2. The atmosphere continuous sintering furnace for preparing aluminum oxynitride powder according to claim 1, characterized in that, The atmosphere continuous sintering furnace body is of a horizontal structure throughout; The furnace body is composed of a shell, a heat-insulating layer, a heating element and a channel from outside to inside, and a conveying guide rail is arranged in the channel; At least one set of dust collection pipelines are arranged at intervals on the furnace body, one end of the dust collection pipeline penetrates through the bottom wall of the furnace body and leads to the channel, and the other end of the dust collection pipeline leads to the outside and is connected to a dust collection tank; At least one set of nitrogen injection pipelines are arranged at intervals on the furnace body, one end of the nitrogen injection pipeline penetrates through the side wall of the furnace body and leads to the channel, and the other end of the nitrogen injection pipeline leads to the outside and is connected to a nitrogen supply device.

3. The atmosphere continuous sintering furnace for preparing aluminum oxynitride powder according to claim 2, characterized in that, The heat-insulating layer adopts a graphite felt purified at a high temperature of 2300 °C and is fixed to the shell by graphite bolts.

4. The atmosphere continuous sintering furnace for preparing aluminum oxynitride powder according to claim 2, characterized in that, The heating element adopts high-purity isostatic graphite with a density ≥ 1.85 g / cm3.

5. The atmosphere continuous sintering furnace for preparing aluminum oxynitride powder according to claim 1 or 2, characterized in that, The furnace body is divided into three sections in total, including: The preheating section includes three temperature zones of 500 °C, 800 °C and 1200 °C; The high-temperature section includes three temperature zones of 1600 °C, 1950 °C and 1600 °C; The cooling section includes a 1200 °C buffer temperature zone, a circulating water cooling zone and a forced air cooling zone, and no heating element is arranged in the cooling section.

6. The atmosphere continuous sintering furnace for preparing aluminum oxynitride powder according to claim 1 or 2, characterized in that, Measuring devices are arranged on the furnace body, including a temperature measuring device, a vacuum gauge and / or a pressure measuring device; And / or, a safety valve and / or an exhaust port are also arranged on the furnace body.

7. An atmosphere continuous sintering furnace for preparing aluminum oxynitride powder according to claim 1, characterized in that, The feeding vacuum unit includes: A feeding vacuum chamber, and a feeding side vacuum pump group is connected to the feeding vacuum chamber through a feeding side vacuum pipeline; A feeding conveyor belt, which is used to carry the materials into the feeding vacuum chamber, and the feeding conveyor belt is close to the feeding vacuum chamber; A feeding flap valve, and a feeding flap valve is arranged at the connection between the feeding conveyor belt and the feeding vacuum chamber; A furnace feeding conveyor belt, one end of which is close to the feeding vacuum chamber and the other end extends into the furnace body; And a furnace inlet flap valve, and a furnace inlet flap valve is arranged at the connection between the feeding vacuum chamber and the furnace feeding conveyor belt.

8. The atmosphere continuous sintering furnace for preparing aluminum oxynitride powder according to claim 7, characterized in that, A feeding oil cylinder is arranged on the feeding conveyor, a furnace inlet oil cylinder is arranged on the furnace feeding conveyor, a feeding proximity switch is arranged in the feeding vacuum chamber, and a nitrogen conveying component is arranged on the feeding vacuum chamber; When the materials are placed on the feeding conveyor belt, the feeding flap valve opens, the feeding oil cylinder pushes the materials into the feeding vacuum chamber, after the feeding proximity switch touches the materials, the feeding oil cylinder withdraws, the feeding flap valve closes, and at the same time the vacuum pump group starts. When the pressure in the feeding vacuum chamber ≤ 5 Pa, the vacuum pump group stops, and nitrogen is filled into the feeding vacuum chamber by the nitrogen conveying component. After the pressure reaches the same as the pressure in the furnace body, the furnace inlet flap valve and the furnace outlet flap valve open; the furnace inlet oil cylinder starts and pushes the materials into the furnace body, and the furnace inlet flap valve and the furnace outlet flap valve close.

9. The atmosphere continuous sintering furnace for preparing aluminum oxynitride powder according to claim 1, characterized in that, The discharging vacuum unit includes: A discharging vacuum chamber, and a discharging side vacuum pump group is connected to the discharging vacuum chamber through a discharging side vacuum pipeline; The discharging conveyor belt, one end extends into the furnace body, and the other end is close to the discharging vacuum chamber; The discharging flap valve, a discharging flap valve is provided at the connection between the discharging vacuum chamber and the discharging conveyor belt; The discharging conveyor belt, the discharging conveyor belt is close to the discharging vacuum chamber and is used to output the finished product; And the discharging flap valve, a discharging flap valve is provided at the connection between the discharging conveyor belt and the discharging vacuum chamber.

10. The atmosphere continuous sintering furnace for preparing aluminum oxynitride powder according to claim 9, characterized in that, A discharging oil cylinder is provided on the opposite side of the discharging conveyor belt, a discharging proximity switch is provided in the discharging vacuum chamber, and a nitrogen delivery component is provided on the feeding vacuum chamber; The discharging flap valve is opened, the discharging conveyor belt pushes the finished product in the furnace to the discharging vacuum chamber. After the discharging proximity switch touches the material, the discharging flap valve is closed, the discharging flap valve is closed, and the discharging side vacuum pump group is started. When the pressure in the vacuum chamber ≤ 5Pa, the vacuum pump group stops, and nitrogen is filled into the discharging vacuum chamber until the pressure is the same as that in the furnace. The discharging flap valve is opened and the finished product is pushed to the discharging conveyor belt by the discharging oil cylinder.

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