Continuous furnace for synthesizing aluminum nitride powder

Abstract

A continuous furnace for synthesizing aluminum nitride powder comprises a buffer section, a heating section, a reaction section and a cooling section, the discharging end of the buffer section is adjacent to the feeding end of the heating section, the discharging end of the heating section is adjacent to the feeding end of the reaction section, the discharging end of the reaction section is adjacent to the feeding end of the cooling section, the buffer section is provided with a first nitrogen inlet and a first nitrogen outlet, and the first nitrogen outlet is provided with a second nitrogen outlet. The first nitrogen inlet is formed in the side, close to the feeding opening, of the sealing valve, and the first nitrogen outlet is formed in the side, close to the heating section, of the sealing valve; the cooling section is provided with a second nitrogen inlet and a second nitrogen outlet, the second nitrogen inlet is formed in the side, close to the discharging opening, of the sealing valve, and the second nitrogen outlet is formed in the side, close to the reaction section, of the sealing valve; a mixed gas outlet is formed in one side, close to the buffer section, of the heating section, and mixed gas of nitrogen and carbon monoxide is discharged from the mixed gas outlet.

Description

Technical Field

[0001] The utility model relates to the technical field of continuous furnaces, in particular to a continuous furnace for synthesizing aluminum nitride powder. Background Art

[0002] Aluminum nitride has high thermal conductivity, high insulation, high strength and a thermal expansion coefficient close to that of silicon. It is a semiconductor packaging material with excellent performance. At present, the main synthesis method of high-performance aluminum nitride powder is carbon thermal reduction nitridation, that is, Al2O3+3C+N2↑→2AlN+3CO↑. This process uses aluminum oxide powder and excess carbon source as raw materials to complete the reaction process in a flowing nitrogen atmosphere. In the prior art, there are two ways to synthesize aluminum nitride powder: 1) intermittent synthesis, which has low uniformity of temperature field in the furnace, poor stability between batches, and requires a long heating and cooling process each time; 2) continuous synthesis, the specific process is that the material boat containing the reaction precursor (aluminum oxide-carbon source) enters the continuous synthesis furnace through the conveying track, and the precursor is gradually heated in the process of entering the continuous furnace until the temperature reaches the reaction conditions, and carbon and aluminum oxide react to form aluminum nitride in a nitrogen atmosphere. The temperature of the reaction zone in the continuous furnace is as high as 1400~1700℃. During the operation of the continuous furnace, the hot air flow will cause thermal shock to the sealing valves at the inlet and outlet of the continuous furnace. Since the sealing valves mainly rely on rubber for sealing, the service life of the sealing valves will be reduced. Summary of the invention

[0003] In view of this, it is necessary to provide a continuous furnace for synthesizing aluminum nitride powder which can prolong the service life of the sealing valve and has low energy consumption.

[0004] A continuous furnace for synthesizing aluminum nitride powder comprises a buffer section, a heating section, a reaction section, and a cooling section, wherein the discharge end of the buffer section is adjacent to the feed end of the heating section, the discharge end of the heating section is adjacent to the feed end of the reaction section, and the discharge end of the reaction section is adjacent to the feed end of the cooling section, the buffer section is provided with a first nitrogen inlet and a first nitrogen outlet, the first nitrogen inlet is arranged on a side of a sealing valve close to the feed port, and the first nitrogen outlet is arranged on a side close to the heating section; the cooling section is provided with a second nitrogen inlet and a second nitrogen outlet, the second nitrogen inlet is arranged on a side of a sealing valve close to the discharge port, and the second nitrogen outlet is arranged on a side close to the reaction section; the heating section is provided with a mixed gas outlet on a side close to the buffer section, and a mixed gas of nitrogen and carbon monoxide is discharged from the mixed gas outlet.

[0005] Preferably, the continuous furnace for synthesizing aluminum nitride powder also includes a feed ventilation bin to reduce the pressure difference between the reaction section and the feed port of the continuous furnace. A first feed sealing valve is provided at the middle end of the feed ventilation bin, a second feed sealing valve is provided between the feed ventilation bin and the buffer section, and a first nitrogen ventilation port is provided on the side wall of the feed ventilation bin.

[0006] Preferably, the material boat conveying direction of the feed ventilation bin is perpendicular to the material boat conveying direction of the continuous furnace, and a first electric push rod is provided on the side wall of the feed ventilation bin, and the pushing direction of the first electric push rod is the same as the material boat conveying direction of the feed ventilation bin, so as to change the moving direction of the material boat by the first electric push rod.

[0007] Preferably, the continuous furnace for synthesizing aluminum nitride powder also includes a discharge ventilation bin to reduce the pressure difference between the reaction section and the discharge port of the continuous furnace, a first discharge sealing valve is provided between the discharge ventilation bin and the cooling section, a second discharge sealing valve is provided at the middle end of the discharge ventilation bin, and a second nitrogen ventilation port is provided on the side wall of the discharge ventilation bin.

[0008] Preferably, the material boat conveying direction of the discharge ventilation bin is perpendicular to the material boat conveying direction of the continuous furnace, and a second electric push rod is provided on the side wall of the discharge ventilation bin, and the pushing direction of the second electric push rod is the same as the material boat conveying direction of the discharge ventilation bin, so as to change the moving direction of the material boat by the second electric push rod.

[0009] Preferably, the length of the buffer section is 1.5-3 m, the length of the heating section is 1-3 m, the length of the reaction section is 15-20 m, and the length of the cooling section is 4-6 m.

[0010] Beneficial effects: Compared with the prior art, the continuous furnace for aluminum nitride powder synthesis of the utility model is provided with a buffer section, and a first nitrogen inlet and a first nitrogen outlet are provided in the buffer section. After the nitrogen is introduced, the air pressure of the buffer section is increased. When the hot air flow of the reaction section passes through the heating section, it is hindered by the air pressure of the buffer section, and the hot air flow is discharged from the mixed gas outlet, thereby preventing the hot air flow from causing thermal shock to the sealing valve at the feeding port of the continuous furnace, and improving the service life of the sealing valve at the feeding port of the continuous furnace. A second nitrogen inlet and a second nitrogen outlet are provided in the cooling section. After the nitrogen is introduced, the air pressure of the cooling section is increased, so that the hot air flow flows in the direction of the mixed gas outlet, thereby preventing the hot air flow from causing thermal shock to the sealing valve at the feeding port of the continuous furnace, and improving the service life of the sealing valve at the feeding port of the continuous furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a top view of the continuous furnace for synthesizing aluminum nitride powder of the utility model.

[0012] Figure 2 It is a front view of the continuous furnace for synthesizing aluminum nitride powder of the utility model.

[0013] In the figure: a continuous furnace 10 for aluminum nitride powder synthesis, a buffer section 20, a first nitrogen inlet 201, a first nitrogen outlet 202, a heating section 30, a mixed gas outlet 301, a reaction section 40, a cooling section 50, a second nitrogen inlet 501, a second nitrogen outlet 502, a feed ventilation bin 60, a first feed sealing valve 601, a second feed sealing valve 602, a first electric push rod 603, a discharge ventilation bin 70, a first discharge sealing valve 701, a second discharge sealing valve 702, and a second electric push rod 703. DETAILED DESCRIPTION

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0015] Please see Figure 1 and Figure 2 A continuous furnace 10 for synthesizing aluminum nitride powder includes a buffer section 20, a heating section 30, a reaction section 40, and a cooling section 50. The discharge end of the buffer section 20 is adjacent to the feed end of the heating section 30, the discharge end of the heating section 30 is adjacent to the feed end of the reaction section 40, and the discharge end of the reaction section 40 is adjacent to the feed end of the cooling section 50. The buffer section 20 is provided with a first nitrogen inlet 201 and a first nitrogen outlet 202. The first nitrogen inlet 201 is arranged in a close proximity to the feed port. On one side of the sealing valve, the first nitrogen outlet 202 is arranged on the side close to the heating section 30; the cooling section 50 is provided with a second nitrogen inlet 501 and a second nitrogen outlet 502, the second nitrogen inlet 501 is arranged on the side of the sealing valve close to the discharge port, and the second nitrogen outlet 502 is arranged on the side close to the reaction section 40; the heating section 30 is provided with a mixed gas outlet 301 on the side close to the buffer section 20, and the mixed gas of nitrogen and carbon monoxide is discharged from the mixed gas outlet 301.

[0016] The buffer section 20 of the utility model is used to reduce the thermal shock of the temperature rising section 30 on the sealing valve of the feed port. Due to the limited space in the continuous furnace, after the material boat enters the continuous furnace, the upper end of the material boat forms a narrow airflow channel with the top of the furnace. The first nitrogen inlet 201 and the first nitrogen outlet 202 are arranged in the first buffer section 20. After nitrogen is introduced into the first nitrogen inlet 201, the airflow channel formed along the direction of the first nitrogen inlet 201 and the direction of the first nitrogen outlet 202 increases the air pressure of the buffer section 20. When the hot air flow formed by carbon monoxide and nitrogen in the reaction section 40 passes through the temperature rising section 30 from the reaction section 40, it meets the nitrogen airflow of the buffer section 20, thereby achieving air pressure balance, thereby avoiding the thermal shock of the heat flow on the sealing valve of the feed port of the continuous furnace, and improving the service life of the sealing valve of the feed port. The nitrogen in the buffer section 20 can circulate, thereby improving the utilization rate of nitrogen.

[0017] The utility model further provides a second nitrogen inlet 501 and a second nitrogen outlet 502 in the cooling section 50. After nitrogen is introduced into the second nitrogen inlet 501, an air flow channel is formed along the direction of the second nitrogen inlet 501 and the direction of the second nitrogen outlet 502, thereby increasing the air pressure of the buffer section 20, so that the hot air flow formed by the carbon monoxide and nitrogen in the reaction section 40 can only flow along the direction of the mixed gas outlet 301, thereby avoiding the thermal shock of the heat flow on the sealing valve of the discharge port of the continuous furnace, and increasing the service life of the sealing valve of the discharge port.

[0018] Since nitrogen is always entering the reaction section 40 and is generated by carbon monoxide, the air pressure of the reaction section 40 is relatively high, so that the air pressure in the continuous furnace is higher than that in the outside world. After the sealing valve of the feed port is opened, the heat flow will flow to the outside world, and at the same time, a small amount of air from the outside world will also enter the continuous furnace. In order to reduce heat loss and prevent air from entering the continuous furnace, affecting the atmosphere in the furnace. In a preferred embodiment, the continuous furnace 10 for aluminum nitride powder synthesis also includes a feed ventilation bin 60 to reduce the pressure difference between the reaction section 40 and the feed port of the continuous furnace, and the middle end of the feed ventilation bin 60 is provided with a first feed sealing valve 601, and a second feed sealing valve 602 is provided between the feed ventilation bin 60 and the buffer section 20, and the side wall of the feed ventilation bin 60 is provided with a first nitrogen ventilation port.

[0019] After the material boat enters the feed ventilation bin 60, the first feed sealing valve 601 and the second feed sealing valve 602 are closed, the feed ventilation bin 60 is evacuated, and then nitrogen is filled into the feed ventilation bin 60 through the first nitrogen ventilation port, so that the air pressure in the feed ventilation bin 60 is slightly greater than the air pressure in the buffer section 20, and then the second feed ventilation bin 60 is opened to allow the material boat to enter the buffer section 20. The high air pressure in the feed ventilation bin 60 can reduce the flow of hot air flow and reduce heat loss. At the same time, the nitrogen atmosphere in the feed ventilation bin 60 can also prevent external air from entering the continuous furnace.

[0020] In a preferred embodiment, the material boat conveying direction of the feed ventilation bin 60 is perpendicular to the material boat conveying direction of the continuous furnace, and a first electric push rod 603 is provided on the side wall of the feed ventilation bin 60. The pushing direction of the first electric push rod 603 is the same as the material boat conveying direction of the feed ventilation bin 60, so as to change the moving direction of the material boat by the first electric push rod 603.

[0021] Similarly, when the material boat is transported out of the continuous furnace, the sealing valve of the discharge port needs to be opened. In order to reduce heat loss and air entering the continuous furnace, in a preferred embodiment, the continuous furnace 10 for aluminum nitride powder synthesis also includes a discharge ventilation bin 70 to reduce the pressure difference between the reaction section 40 and the discharge port of the continuous furnace. A first discharge sealing valve 701 is provided between the discharge ventilation bin 70 and the cooling section 50, a second discharge sealing valve 702 is provided at the middle end of the discharge ventilation bin 70, and a second nitrogen ventilation port is provided on the side wall of the discharge ventilation bin 70.

[0022] After the material boat is moved out of the discharge ventilation bin 70, the second discharge sealing valve 702 is closed, the discharge sealing valve is evacuated and filled with nitrogen from the second nitrogen ventilation port, so that the air pressure in the discharge sealing bin is slightly greater than the air pressure in the cooling section 50, thereby reducing heat loss and allowing air to enter the continuous furnace.

[0023] In a preferred embodiment, the material boat conveying direction of the discharge ventilation bin 70 is perpendicular to the material boat conveying direction of the continuous furnace, and a second electric push rod 703 is provided on the side wall of the discharge ventilation bin 70. The pushing direction of the second electric push rod 703 is the same as the material boat conveying direction of the discharge ventilation bin 70, so as to change the moving direction of the material boat by the second electric push rod 703.

[0024] In a preferred embodiment, the length of the buffer section 20 is 1.5-3 m, the length of the heating section 30 is 1-3 m, the length of the reaction section 40 is 15-20 m, and the length of the cooling section 50 is 4-6 m.

[0025] In a preferred embodiment, the continuous furnace 10 for aluminum nitride powder synthesis also includes a first air pressure control mechanism to control the air pressure balance between the buffer section 20 and the heating section 30. The first air pressure control mechanism includes a first pressure sensor, a first controller, and a first variable frequency induced draft fan. The first pressure sensor is arranged between the first nitrogen outlet 202 and the mixed gas outlet 301 to collect real-time air pressure information between the buffer section 20 and the heating section 30. The first pressure sensor is electrically connected to the first controller to transmit the real-time pressure information to the first controller. The first controller is also electrically connected to the first variable frequency induced draft fan. The first controller is provided with multiple pressure thresholds, and the first controller can convert the real-time pressure information into a real-time pressure value. When the real-time pressure value is within a certain pressure threshold, the first controller correspondingly adjusts the speed of the first variable frequency induced draft fan to balance the air pressure between the buffer section 20 and the heating section 30.

[0026] In a preferred embodiment, the continuous furnace 10 for aluminum nitride powder synthesis further includes a second air pressure control mechanism to control the air pressure balance between the reaction section 40 and the cooling section 50, and the second air pressure control mechanism includes a second pressure sensor, a second controller, and a second variable frequency induced draft fan. The second pressure sensor is arranged between the second nitrogen outlet 502 and the reaction section 40 to collect real-time air pressure information between the reaction section 40 and the cooling section 50, the second pressure sensor is electrically connected to the second controller to transmit the real-time pressure information to the second controller, the second controller is also electrically connected to the second variable frequency induced draft fan, the second controller is provided with a plurality of pressure thresholds, and the second controller can convert the real-time pressure information into a real-time pressure value, when the real-time pressure value is within a certain pressure threshold, the second controller correspondingly adjusts the speed of the second variable frequency induced draft fan to balance the air pressure between the reaction section 40 and the cooling section 50.

[0027] The above disclosure is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope covered by the utility model.

Claims

1. A continuous furnace for synthesizing aluminum nitride powder, characterized in that: The invention comprises a buffer section, a heating section, a reaction section and a cooling section, wherein the discharge end of the buffer section is adjacent to the feed end of the heating section, the discharge end of the heating section is adjacent to the feed end of the reaction section, and the discharge end of the reaction section is adjacent to the feed end of the cooling section. The buffer section is provided with a first nitrogen inlet and a first nitrogen outlet, wherein the first nitrogen inlet is arranged on a side of a sealing valve close to the feed port, and the first nitrogen outlet is arranged on a side close to the heating section; the cooling section is provided with a second nitrogen inlet and a second nitrogen outlet, wherein the second nitrogen inlet is arranged on a side of a sealing valve close to the discharge port, and the second nitrogen outlet is arranged on a side close to the reaction section; the heating section is provided with a mixed gas outlet on a side close to the buffer section, and a mixed gas of nitrogen and carbon monoxide is discharged from the mixed gas outlet.

2. The continuous furnace for synthesizing aluminum nitride powder according to claim 1, characterized in that: The continuous furnace for synthesizing aluminum nitride powder also includes a feed ventilation bin to reduce the pressure difference between the reaction section and the feed port of the continuous furnace. A first feed sealing valve is provided at the middle end of the feed ventilation bin, a second feed sealing valve is provided between the feed ventilation bin and the buffer section, and a first nitrogen ventilation port is provided on the side wall of the feed ventilation bin.

3. The continuous furnace for synthesizing aluminum nitride powder according to claim 2, characterized in that: The material boat conveying direction of the feed ventilation bin is perpendicular to the material boat conveying direction of the continuous furnace. A first electric push rod is provided on the side wall of the feed ventilation bin. The pushing direction of the first electric push rod is the same as the material boat conveying direction of the feed ventilation bin, so as to change the moving direction of the material boat through the first electric push rod.

4. The continuous furnace for synthesizing aluminum nitride powder according to claim 1, characterized in that: The continuous furnace for synthesizing aluminum nitride powder also includes a discharge ventilation bin to reduce the pressure difference between the reaction section and the discharge port of the continuous furnace. A first discharge sealing valve is provided between the discharge ventilation bin and the cooling section, a second discharge sealing valve is provided at the middle end of the discharge ventilation bin, and a second nitrogen ventilation port is provided on the side wall of the discharge ventilation bin.

5. The continuous furnace for synthesizing aluminum nitride powder according to claim 4, characterized in that: The material boat conveying direction of the discharge ventilation bin is perpendicular to the material boat conveying direction of the continuous furnace. A second electric push rod is provided on the side wall of the discharge ventilation bin. The pushing direction of the second electric push rod is the same as the material boat conveying direction of the discharge ventilation bin, so as to change the moving direction of the material boat by the second electric push rod.

6. The continuous furnace for synthesizing aluminum nitride powder according to claim 1, characterized in that: The length of the buffer section is 1.5-3 m, the length of the heating section is 1-3 m, the length of the reaction section is 15-20 m, and the length of the cooling section is 4-6 m.

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