Dispersion strengthening type aluminum oxide roasting device and method

Abstract

The invention provides a device and a method for roasting dispersion strengthened aluminum oxide, a blanking pipe of a cyclone separator is connected with a buffer tank, the top of the buffer tank is connected with a feed port of a first-stage cooling cyclone, and an ascending pipe of a second-stage cooling cyclone is connected with the bottom of the buffer tank; an upper fuel nozzle set and a lower fuel nozzle set are arranged on the inner side wall of a combustion chamber of the main roasting furnace in the vertical direction at intervals, and each of the upper fuel nozzle set and the lower fuel nozzle set is composed of a plurality of fuel nozzles evenly distributed in the circumferential direction at intervals. According to the invention, the dispersion effect of the fuel is enhanced, the temperature of the aluminum hydroxide roasting main furnace is reduced to below 1000 DEG C, and the purposes of energy conservation and consumption reduction are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of roasting technology, and more specifically to a dispersion-strengthened alumina roasting device and method. Background Art

[0002] Aluminum hydroxide roasting is the last process in alumina production. Its purpose is to achieve high-temperature removal of aluminum hydroxide attached water and crystal water and partial transformation of the crystal form of aluminum oxide. Only after the roasting process can the aluminum oxide product that meets certain requirements be obtained. Aluminum hydroxide roasting technology can be divided into three types: traditional rotary kiln roasting, modified rotary kiln roasting and fluidized roasting. Fluidized roasting technology has also undergone a development process from dense phase fluidized bed to dense phase-dilute phase combination. Currently, the roasting technologies widely used in alumina production are Alcoa's flash roasting, Germany's circulation roasting, and Denmark's gas suspension roasting. Among them, gas suspension roasting technology started the latest, but it is advanced in technology and is currently the most widely used roasting technology. During roasting, the main furnace temperature generally reaches 1100~1200℃, and the energy consumption is generally between 3.0-3.2GJ / t AO. In the actual production process, in order to ensure that the product quality meets the production standards, the main furnace temperature of the gaseous suspension roasting furnace needs to be higher than the temperature required for the dehydration of aluminum hydroxide and partial crystal transformation, which directly increases the energy consumption of the roasting process.

[0003] The gas suspension roasting furnace is mainly composed of two-stage preheating cyclones, a roasting main furnace and its connected cyclone separator, a four-stage cooling cyclone and a Venturi dryer. During the roasting process, the raw materials enter from the Venturi, and the air enters from the fourth-stage cooling cyclone. The combustion air is preheated by heat exchange with the finished alumina and then reacts with the fuel at the bottom of the main furnace to provide energy for the subsequent dehydration of aluminum hydroxide. During the roasting process, the temperature of the roasting main furnace and its connected cyclone separator is as high as 1100~1200℃, which results in high energy consumption and high costs. Summary of the invention

[0004] One of the purposes of the present invention is to provide a dispersion-strengthened alumina roasting device and method, which can reduce the temperature of the main furnace for roasting aluminum hydroxide to below 1000°C and reduce the fuel consumption during the roasting of aluminum hydroxide, thereby reducing production costs.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a dispersion-enhanced alumina roasting device, in which the feed pipe of the cyclone separator is connected to the buffer tank, the top of the buffer tank is connected to the feed port of the primary cooling cyclone, and the riser of the secondary cooling cyclone is connected to the bottom of the buffer tank; an upper fuel nozzle group and a lower fuel nozzle group are arranged at intervals along the vertical direction on the inner wall of the combustion chamber of the main roasting furnace, and the upper fuel nozzle group and the lower fuel nozzle group are respectively composed of a plurality of fuel nozzles uniformly distributed along the circumferential intervals. This design is intended to ensure that the fuel can be fully burned in the main roasting furnace and provide a uniform and efficient heating environment. The layered fuel nozzle groups can better control the flame morphology and the distribution of the flames, thereby achieving a better roasting effect and reducing nitrogen oxide emissions.

[0006] Furthermore, the discharge port of the cyclone separator is connected to two feed legs through a main pipe, and the two feed legs are respectively connected to the middle of both sides of the buffer tank. The two feed legs ensure that the material is evenly distributed in the buffer tank, and the symmetrical feed port design of the buffer tank can appropriately slow down the speed of the rising airflow and enhance the dispersion effect of the particles entering from the two feed leg inlets in the gas.

[0007] Furthermore, the Venturi dryer is connected to the feed port of the primary preheating cyclone through a riser, and the riser of the secondary preheating cyclone is connected to the bottom of the Venturi dryer; the discharge port of the secondary preheating cyclone is connected to the middle of the main roasting furnace through a material leg; the discharge port of the primary preheating cyclone is connected to the riser of the cyclone separator; and the riser of the cyclone separator is connected to the top of the secondary preheating cyclone. In this process, the materials separated from the cyclone separator will be reintroduced into the secondary preheating cyclone, forming a closed cycle to ensure that all materials reach an ideal preheating state.

[0008] Furthermore, the riser of the primary cooling cyclone is connected to the air inlet of the main combustion furnace; the bottom leg of the primary cooling cyclone is connected to the riser of the third cooling cyclone, the riser of the third cooling cyclone is connected to the feed port of the secondary cooling cyclone, the bottom leg of the secondary cooling cyclone is connected to the riser of the fourth cooling cyclone, the riser of the fourth cooling cyclone is connected to the feed port of the third cooling cyclone, the bottom leg of the third cooling cyclone is connected to the cooling air duct, and the cooling air duct is connected to the feed port of the fourth cooling cyclone. Through the multi-stage cooling cyclone, the material is gradually cooled to a suitable temperature range for subsequent processing or collection.

[0009] Further, the number of fuel nozzles in the upper fuel nozzle group and the lower fuel nozzle group is 4-8.

[0010] Furthermore, the fuel nozzles in the upper fuel nozzle group and the lower fuel nozzle group are arranged radially.

[0011] Furthermore, the angle between the axis of each fuel nozzle of the upper fuel nozzle group and the lower fuel nozzle group and the horizontal plane is an elevation angle θ°, and the elevation angle θ° is 1 to 20°; at the same time, the angle between the axis of each fuel nozzle of the upper fuel nozzle group and the lower fuel nozzle group and the wall normal is a rotation angle γ° in the same clockwise direction, and the rotation angle γ° is 1 to 30°.

[0012] Furthermore, a dispersion-strengthened alumina calcining method is also provided, comprising the following steps: S1. After gas-solid separation in the cyclone separator, the alumina particles are connected to two feed legs through a main pipe and enter the buffer tank from the middle of both sides of the buffer tank through the two feed legs; At the same time, the combustion air delivered by the secondary preheating cyclone enters the buffer tank from the bottom, where the alumina particles and the combustion air are further evenly mixed to fully exchange heat; S2. The mixed gas in the buffer tank is sent to the primary cooling cyclone for gas-solid separation. The preheated air obtained after separation is sent from the bottom to the main roasting furnace, enters the combustion chamber, and mixes with the fuel in it; S3, the upper fuel nozzle group and the lower fuel nozzle group are arranged at intervals in the vertical direction on the inner side wall of the combustion chamber in the main roasting furnace, and the upper fuel nozzle group and the lower fuel nozzle group are alternately pulse-sprayed, and a single group is pulse-sprayed, and the pulse interval t=0.2s; The preheated air is mixed with the fuel and ignited, releasing heat to provide the required energy for the reaction, completing the final dehydration process of aluminum hydroxide and the crystal transformation of part of the aluminum oxide in the main roasting furnace.

[0013] Furthermore, a dispersion-strengthened alumina calcining method is also provided, comprising the following steps: S1. After gas-solid separation in the cyclone separator, the alumina particles are connected to two feed legs through a main pipe and enter the buffer tank from the middle of both sides of the buffer tank through the two feed legs; At the same time, the combustion air transported by the intake pipe enters the buffer tank from the bottom, where the alumina particles and the combustion air are further evenly mixed to fully exchange heat; S2. The mixed gas in the buffer tank is sent to the primary cooling cyclone for gas-solid separation. The preheated air obtained after separation is sent from the bottom to the main roasting furnace, enters the combustion chamber, and mixes with the fuel in it; S3, the included angle between the axis of each fuel nozzle of the upper fuel nozzle group and the lower fuel nozzle group and the horizontal plane is an elevation angle θ°, and the included angle between the axis of each fuel nozzle of the upper fuel nozzle group and the wall normal is a clockwise rotation angle γ°. By adjusting the angles θ° and γ° of the nozzles, the fuel is sprayed at a specific angle to generate an annular flow zone, thereby accelerating mass transfer, heat transfer and reaction; The upper fuel nozzle group and the lower fuel nozzle group perform pulse injection alternately, and a single group performs pulse injection mode, with a pulse interval t=0.2s; The preheated air and fuel mixture is ignited, completing the final dehydration process of aluminum hydroxide and partial crystal transformation of aluminum oxide in the main roasting furnace.

[0014] The beneficial effects of the present invention are as follows: The present invention gradually preheats the material through a multi-stage preheating cyclone, then performs high-temperature treatment in a main roasting furnace, then utilizes a buffer tank to enhance particle dispersion and heat exchange effects, and finally gradually cools the treated material through a multi-stage cooling cyclone. During the whole process, the design of the nozzle fuel ensures efficient combustion and heat transfer, thereby achieving the purpose of energy saving and consumption reduction.

[0015] The preferred embodiment 1 of the present invention adopts a radially arranged nozzle setting structure, which emphasizes the pulse injection of fuel and enhances the fuel dispersion effect by grouped alternating injection.

[0016] The second scheme of the present invention adopts a nozzle setting structure with a specific angle, focusing on the angle adjustment of the fuel nozzle. By setting specific elevation and rotation angles, as well as the position distribution of the fuel nozzle, the fuel injection method is optimized to form an annular flow zone, thereby promoting mass transfer, heat transfer and reaction efficiency.

[0017] The core of these two solutions is to increase and decrease the roasting temperature through improved buffer tank design and optimized fuel injection method, so as to achieve the purpose of energy saving and consumption reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 A schematic diagram of the structure of a dispersion-strengthened alumina roasting device provided by the present invention; Figure 2 A schematic diagram of the structure of a nozzle of a dispersion-enhanced alumina roasting device provided by the present invention; The serial numbers, structures and names of the various parts in the figure are as follows: 1. First-stage preheating cyclone; 2. Second-stage preheating cyclone; 3. Cyclone separator; 4. Main roasting furnace; 5. Buffer tank; 6. First-stage cooling cyclone; 7. Second-stage cooling cyclone; 8. Third-stage cooling cyclone; 9. Fourth-stage cooling cyclone; 10. Venturi dryer; 11. Combustion chamber; 12. Combustion nozzle; 13. Cooling air duct. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Example 1

[0021] See also Figure 1-2 Now, for a dispersion-enhanced alumina roasting device provided by the present invention, the discharge pipe of the cyclone separator 3 is connected to the buffer tank 5, the top of the buffer tank 5 is connected to the feed port of the primary cooling cyclone 6, and the riser of the secondary cooling cyclone 7 is connected to the bottom of the buffer tank 5; an upper fuel nozzle group and a lower fuel nozzle group are arranged on the inner side wall of the combustion chamber 11 of the main roasting furnace 4 at intervals in the vertical direction, and the upper fuel nozzle group and the lower fuel nozzle group are respectively composed of a plurality of fuel nozzles 12 uniformly distributed along the circumferential intervals.

[0022] See also Figure 1 The discharge port of the cyclone separator 3 is connected to two feed legs through a main pipe, and the two feed legs are respectively connected to the middle of both sides of the buffer tank 5.

[0023] See also Figure 1 The venturi dryer 10 is connected to the feed port of the primary preheating cyclone 1 through a riser, and the riser of the secondary preheating cyclone 2 is connected to the bottom of the venturi dryer 10; the discharge port of the secondary preheating cyclone 2 is connected to the middle of the main roasting furnace 4 through a material leg; the discharge port of the primary preheating cyclone 1 is connected to the riser of the cyclone separator 3; the riser of the cyclone separator 3 is connected to the top of the secondary preheating cyclone 2.

[0024] See also Figure 1 The riser of the first-stage cooling cyclone 6 is connected to the air inlet of the main combustion furnace 4; the bottom leg of the first-stage cooling cyclone 6 is connected to the riser of the third-stage cooling cyclone 8, the riser of the third-stage cooling cyclone 8 is connected to the feed port 7 of the second-stage cooling cyclone, the bottom leg of the second-stage cooling cyclone 7 is connected to the riser of the fourth-stage cooling cyclone 9, the riser of the fourth-stage cooling cyclone 9 is connected to the feed port of the third-stage cooling cyclone 8, the bottom leg of the third-stage cooling cyclone 8 is connected to the cooling air duct 13, and the cooling air duct 13 is connected to the feed port of the fourth-stage cooling cyclone 9.

[0025] See also Figure 2 The number of fuel nozzles 12 in the upper fuel nozzle group and the lower fuel nozzle group is 6.

[0026] See also Figure 2 The fuel nozzles 12 in the upper fuel nozzle group and the lower fuel nozzle group are arranged radially. Example 2

[0027] The basic structure is basically the same as that of Example 1, except that the nozzle arrangement of the upper fuel nozzle group and the lower fuel nozzle group is different, as follows: See also Figure 2 The angle between the axis of each fuel nozzle 12 of the upper fuel nozzle group and the lower fuel nozzle group and the horizontal plane is an elevation angle θ°, and the elevation angle θ° is 1 to 20°; at the same time, the angle between the axis of each fuel nozzle 12 of the upper fuel nozzle group and the lower fuel nozzle group and the wall normal is a rotation angle γ° in the same clockwise direction, and the rotation angle γ° is 1 to 30°. Example 3

[0028] Based on the dispersion-strengthened alumina device of Example 1, the dispersion-strengthened alumina roasting method comprises the following complete steps: S1, the aluminum hydroxide raw material containing attached water enters from the Venturi dryer 10, and the attached water is removed in the Venturi dryer 10 and the riser connected to the inlet of the first-stage preheating cyclone 1 by the Venturi dryer 10, and then enters the first-stage preheating cyclone 1 for separation; S2, the particles after dehydration, preheating and gas-solid separation in the first-stage preheating cyclone 1 fall from the feed leg of the first-stage preheating cyclone 1 into the feed port of the second-stage preheating cyclone 2 connected to the feed leg; S3, the particles after dehydration, preheating and gas-solid separation in the secondary preheating cyclone 2 enter the feed port of the roasting main furnace 4 connected to the feed leg through the feed leg of the secondary preheating cyclone 2 for roasting operation; S4, the roasted alumina enters the cyclone separator 3 connected to the top pipeline of the roasting main furnace 4 for gas-solid separation; S5, the alumina particles after gas-solid separation in the cyclone separator 3 are connected to two feed legs through a main pipe, and enter the buffer tank 5 from the middle of both sides of the buffer tank 5 through the two feed legs; At the same time, the combustion air transported by the air intake pipe enters the buffer tank 5 from the bottom, and the alumina particles and the combustion air are further evenly mixed in the buffer tank 5 to fully exchange heat; S6, the mixed gas in the buffer tank 5 is sent to the primary cooling cyclone 6 for gas-solid separation, and the preheated air obtained after separation is sent from the bottom into the roasting main furnace 4, enters the combustion chamber 11, and mixes with the fuel therein; S7, in this embodiment, the nozzle arrangement of scheme 1 is as follows Figure 2 (a), the upper fuel nozzle group and the lower fuel nozzle group are arranged in a vertical direction on the inner side wall of the combustion chamber 11 in the main roasting furnace 4, and the upper fuel nozzle group is grouped as follows: Figure 2 (c) The grouping of the lower fuel nozzle group is as follows Figure 2(d) The upper fuel nozzle group and the lower fuel nozzle group perform pulse injection alternately, and a single group performs pulse injection, with a pulse interval of t = 0.2s; The preheated air and fuel mixture is ignited, and the final dehydration process of aluminum hydroxide and the crystal transformation of part of aluminum oxide are completed in the main roasting furnace 4; S9. The separated particles pass through the material leg of the first-stage cooling cyclone 6 and enter the second-stage cooling cyclone 7 connected to the material leg for cooling and gas-solid separation. The separated particles pass through the material leg of the second-stage cooling cyclone 7 and enter the third-stage cooling cyclone 8 connected to the material leg for cooling and gas-solid separation. The separated particles pass through the material leg of the third-stage cooling cyclone 8 and enter the fourth-stage cooling cyclone 9 connected to the material leg for cooling and gas-solid separation. The separated particles enter the next link to be collected. Example 4

[0029] Based on the dispersion-strengthened alumina device of Example 2, the dispersion-strengthened alumina roasting method comprises the following complete steps: S1, the aluminum hydroxide raw material containing attached water enters from the Venturi dryer 10, and the attached water is removed in the Venturi dryer 10 and the riser connected to the inlet of the first-stage preheating cyclone 1 by the Venturi dryer 10, and then enters the first-stage preheating cyclone 1 for separation; S2, the particles after dehydration, preheating and gas-solid separation in the first-stage preheating cyclone 1 fall from the feed leg of the first-stage preheating cyclone 1 into the feed port of the second-stage preheating cyclone 2 connected to the feed leg; S3, the particles after dehydration, preheating and gas-solid separation in the secondary preheating cyclone 2 enter the feed port of the roasting main furnace 4 connected to the feed leg through the feed leg of the secondary preheating cyclone 2 for roasting operation; S4, the roasted alumina enters the cyclone separator 3 connected to the top pipeline of the roasting main furnace 4 for gas-solid separation; S5, the alumina particles after gas-solid separation in the cyclone separator 3 are connected to two feed legs through a main pipe, and enter the buffer tank 5 from the middle of both sides of the buffer tank 5 through the two feed legs; At the same time, the combustion air transported by the air intake pipe enters the buffer tank 5 from the bottom, and the alumina particles and the combustion air are further evenly mixed in the buffer tank 5 to fully exchange heat; S6, the mixed gas in the buffer tank 5 is sent to the primary cooling cyclone 6 for gas-solid separation, and the preheated air obtained after separation is sent from the bottom into the roasting main furnace 4, enters the combustion chamber 11, and mixes with the fuel therein; S7: The nozzle arrangement of the second embodiment of the present invention is as follows: Figure 2 (b), the angle between the axis of each fuel nozzle 12 of the upper fuel nozzle group and the lower fuel nozzle group and the horizontal plane is an elevation angle θ°, and the upper fuel nozzle group is arranged as follows Figure 2(e) The arrangement of the lower fuel nozzle group is as follows Figure 2 (f) The included angles between the axis of each fuel nozzle 12 of the upper fuel nozzle group and the wall normal of the lower fuel nozzle group are the same clockwise rotation angle γ°. The fuel is injected at a specific angle by adjusting the angles θ° and γ° of the nozzles to generate an annular flow zone, thereby accelerating mass transfer, heat transfer and reaction.

[0030] The preheated air is mixed with the fuel and ignited, releasing heat to provide the required energy for the reaction, completing the final dehydration process of aluminum hydroxide and the crystal transformation of part of the aluminum oxide in the main roasting furnace 4; S8. The separated particles pass through the material leg of the first-stage cooling cyclone 6 and enter the second-stage cooling cyclone 7 connected to the material leg for cooling and gas-solid separation. The separated particles pass through the material leg of the second-stage cooling cyclone 7 and enter the third-stage cooling cyclone 8 connected to the material leg for cooling and gas-solid separation. The separated particles pass through the material leg of the third-stage cooling cyclone 8 and enter the fourth-stage cooling cyclone 9 connected to the material leg for cooling and gas-solid separation. After separation, the particles enter the next link to be collected.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A dispersion-strengthened alumina roasting device, characterized in that: The down pipe of the cyclone separator (3) is connected to the buffer tank (5), the top of the buffer tank (5) is connected to the feed port of the primary cooling cyclone (6), and the riser of the secondary cooling cyclone (7) is connected to the bottom of the buffer tank (5); An upper fuel nozzle group and a lower fuel nozzle group are arranged at intervals along the vertical direction on the inner side wall of the combustion chamber (11) of the main roasting furnace (4), and the upper fuel nozzle group and the lower fuel nozzle group are respectively composed of a plurality of fuel nozzles (12) uniformly distributed at intervals along the circumferential direction.

2. A dispersion-strengthened alumina roasting device as claimed in claim 1, characterized in that: The discharge port of the cyclone separator (3) is connected to two feed legs via a main pipe, and the two feed legs are respectively connected to the middle of both sides of the buffer tank (5).

3. A dispersion-strengthened alumina roasting device as claimed in claim 1, characterized in that: The venturi dryer (10) is connected to the feed port of the first-stage preheating cyclone (1) through a riser, and the riser of the second-stage preheating cyclone (2) is connected to the bottom of the venturi dryer (10); the discharge port of the second-stage preheating cyclone (2) is connected to the middle of the main roasting furnace (4) through a feed leg; The discharge port of the first-stage preheating cyclone (1) is connected to the riser of the cyclone separator (3); and the riser of the cyclone separator (3) is connected to the top of the second-stage preheating cyclone (2).

4. A dispersion-strengthened alumina roasting temperature-reducing and energy-saving technology and device as claimed in claim 1, characterized in that: The riser of the first-stage cooling cyclone (6) is connected to the air inlet of the main combustion furnace (4); the bottom leg of the first-stage cooling cyclone (6) is connected to the riser of the third-stage cooling cyclone (8), the riser of the third-stage cooling cyclone (8) is connected to the feed port (7) of the second-stage cooling cyclone (7), the bottom leg of the second-stage cooling cyclone (7) is connected to the riser of the fourth-stage cooling cyclone (9), the riser of the fourth-stage cooling cyclone (9) is connected to the feed port of the third-stage cooling cyclone (8), the bottom leg of the third-stage cooling cyclone (8) is connected to the cooling air duct (13), and the cooling air duct (13) is connected to the feed port of the fourth-stage cooling cyclone (9).

5. A dispersion-strengthened alumina roasting device as claimed in claim 1, characterized in that: The number of fuel nozzles (12) in the upper fuel nozzle group and the lower fuel nozzle group is 4-8.

6. A dispersion-strengthened alumina roasting device as claimed in claim 1, characterized in that: The fuel nozzles (12) in the upper fuel nozzle group and the lower fuel nozzle group are arranged radially.

7. A dispersion-strengthened alumina roasting device as claimed in claim 1, characterized in that: The included angle between the axis of each fuel nozzle (12) of the upper fuel nozzle group and the lower fuel nozzle group and the horizontal plane is an elevation angle θ°, and the elevation angle θ° is 1-20°; At the same time, the angle between the axis of each fuel nozzle (12) of the upper fuel nozzle group and the lower fuel nozzle group and the normal line of the wall surface is a rotation angle γ° in the same clockwise direction, and the rotation angle γ° is 1 to 30°.

8. A method for calcining dispersion-strengthened alumina, characterized in that: The following steps are involved: S1, the alumina particles after gas-solid separation in the cyclone separator (3) are connected to two feed legs through a main pipe, and enter the buffer tank (5) from the middle of both sides of the buffer tank (5) through the two feed legs; At the same time, the combustion air transported by the riser of the secondary preheating cyclone (2) enters the buffer tank (5) from the bottom, and the alumina particles and the combustion air are further evenly mixed in the buffer tank (5) to fully exchange heat; S2, the mixed gas in the buffer tank (5) is sent to the primary cooling cyclone (6) for gas-solid separation, and the preheated air obtained after separation is sent from the bottom into the roasting main furnace (4), enters the combustion chamber (11), and mixes with the fuel therein; S3, an upper fuel nozzle group and a lower fuel nozzle group are arranged at intervals in the vertical direction on the inner side wall of the combustion chamber (11) in the main roasting furnace (4), and the upper fuel nozzle group and the lower fuel nozzle group perform pulse injection alternately, and a single group performs pulse injection mode, and the pulse interval t=0.2s; The preheated air and fuel mixture is ignited, and the final dehydration process of aluminum hydroxide and the crystal transformation of part of aluminum oxide are completed in the main roasting furnace (4).

9. A method for calcining dispersion-strengthened alumina, characterized in that: The following steps are involved: S1, the alumina particles after gas-solid separation in the cyclone separator (3) are connected to two feed legs through a main pipe, and enter the buffer tank (5) from the middle of both sides of the buffer tank (5) through the two feed legs; At the same time, the combustion air transported by the air intake pipe enters the buffer tank (5) from the bottom, and the alumina particles and the combustion air are further evenly mixed in the buffer tank (5) to fully exchange heat; S2, the mixed gas in the buffer tank (5) is sent to the primary cooling cyclone (6) for gas-solid separation, and the preheated air obtained after separation is sent from the bottom into the roasting main furnace (4), enters the combustion chamber (11), and mixes with the fuel therein; S3, the included angle between the axis of each fuel nozzle (12) of the upper fuel nozzle group and the lower fuel nozzle group and the horizontal plane is an elevation angle θ°, the included angle between the axis of each fuel nozzle (12) of the upper fuel nozzle group and the lower fuel nozzle group and the wall normal is a rotation angle γ° in the same clockwise direction, and the fuel is injected at a specific angle by adjusting the angles θ° and γ° of the nozzles; The upper fuel nozzle group and the lower fuel nozzle group perform pulse injection alternately, and a single group performs pulse injection mode, with a pulse interval t=0.2s; The preheated air and fuel mixture is ignited, and the final dehydration process of aluminum hydroxide and the crystal transformation of part of aluminum oxide are completed in the main roasting furnace (4).

Images